DE102023110708A1 - energy storage element and battery - Google Patents

Abstract

A secondary energy storage element (100) comprises a cathode (108) and an anode (105) as electrodes, which are parts of a composite body (104) in which they are separated by a separator or solid electrolyte layer (116) in the sequence cathode (108) / separator or solid electrolyte layer (116) / anode (105). The cathode (108) comprises a cathode current collector (109) and a positive electrode material (110), the anode (105) comprises an anode current collector (106) and a negative electrode material (107). The cathode current collector (109) has a main region which is loaded on both sides with a layer of the positive electrode material (110), as well as a free edge strip (109b) which extends along an edge of the cathode current collector (109) and which is not loaded with the positive electrode material (110). Alternatively or simultaneously, the anode current collector (106) has a main region which is loaded on both sides with a layer of the negative electrode material (107), as well as a free edge strip (106b) which extends along an edge of the anode current collector (106) and which is not loaded with the negative electrode material (107). The cathode (108) and the anode (105) are designed and/or arranged relative to one another within the composite body (104) in such a way that the free edge strip (109b) of the cathode current collector (109) emerges from one side (104b) of the composite body (104) and/or the free edge strip (106b) of the anode current collector (106) emerges from another side (104a) of the composite body (104). The energy storage element comprises a first contact metal sheet (112) which is in direct contact with one of the free edge strips (106b) and/or a second contact metal sheet (109a) which is in direct contact with the other of the free edge strips (109b). The electrodes (105, 108) comprise at least one ion type from the group consisting of sodium ions, potassium ions, calcium ions, magnesium ions and aluminum ions, which are exchanged between the cathode (108) and the anode (105) during charging and discharging of the secondary energy storage element (100).

Description

The invention relates to an energy storage element which is suitable for providing very high currents, as well as a method for producing such an energy storage element.

field of application and state of the art

Electrochemical energy storage elements are able to convert stored chemical energy into electrical energy through a redox reaction. One of the simplest forms of an electrochemical energy storage element is the electrochemical cell. It comprises a positive and a negative electrode, which are separated from each other by a separator, for example. During a discharge, electrons are released at the negative electrode through an oxidation process. This results in an electron current that can be tapped by an external electrical consumer for which the electrochemical cell serves as an energy supplier. At the same time, an ion current corresponding to the electrode reaction occurs within the cell. This ion current passes through the separator and is usually made possible by an ion-conducting electrolyte.

If the discharge is reversible, i.e. if it is possible to reverse the conversion of chemical energy into electrical energy during the discharge and recharge the cell, then the cell is called a secondary cell. The common designation of the negative electrode as anode and the designation of the positive electrode as cathode in secondary cells refers to the discharge function of the electrochemical cell.

Secondary lithium-ion cells are now used as energy storage elements for many applications, as they can provide high currents and are characterized by a comparatively high energy density. They are based on the use of lithium, which can migrate back and forth between the cell's electrodes in the form of ions. The negative electrode and the positive electrode of a lithium-ion cell are usually formed by so-called composite electrodes, which include electrochemically active components as well as electrochemically inactive components.

In principle, all materials that can absorb and release lithium ions can be used as electrochemically active components (active materials) for secondary lithium-ion cells. For example, carbon-based particles such as graphitic carbon are used for the negative electrode. Lithium cobalt oxide (LiCoO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ), lithium iron phosphate (LiFePO ₄ ) or derivatives thereof can be used as active materials for the positive electrode. The electrochemically active materials are usually contained in the electrodes in particle form.

As electrochemically inactive components, the composite electrodes generally comprise a flat and/or strip-shaped current collector, for example a metallic foil, which serves as a carrier for the respective active material. The current collector for the negative electrode (anode current collector) can be made of copper or nickel, for example, and the current collector for the positive electrode (cathode current collector) can be made of aluminum, for example. Furthermore, the electrodes can comprise an electrode binder (e.g. polyvinylidene fluoride (PVDF) or another polymer, for example carboxymethyl cellulose), conductivity-improving additives and other additives as electrochemically inactive components. The electrode binder ensures the mechanical stability of the electrodes and often also the adhesion of the active material to the current collectors.

Lithium-ion cells typically contain electrolytes consisting of solutions of lithium salts such as lithium hexafluorophosphate (LiPF6) in organic solvents (e.g. ethers and esters of carbonic acid).

When manufacturing a lithium-ion cell, the composite electrodes are combined with one or more separators to form a composite body. The electrodes and separators are usually combined under pressure, possibly also by lamination or by gluing. The basic functionality of the cell can then be achieved by impregnating the composite with the electrolyte.

In many embodiments, the composite body is formed in the form of a coil or processed into a coil. Alternatively, the composite body can also be a stack of electrodes.

Analogous to lithium-ion cells, sodium-ion cells, which use the alkali metal sodium in the form of Na ions, potassium-ion cells, which use the alkali metal potassium in the form of potassium ions, calcium-ion cells, which use the alkaline earth metal calcium in the form of calcium ions, magnesium-ion cells, which use the alkaline earth metal magnesium in the form of magnesium ions, and aluminum-ion cells, which use aluminum in the form of aluminum ions, can also be produced. The structure of the composite electrodes and their further processing can basically be adopted 1:1 for cells with these alternative cell chemistries, whereby current collector materials, electrode materials, electrolytes and separators tailored to the respective cell chemistry are used.

Sodium-ion cells in particular have now become practical. In comparison to lithium-ion technology, the production of sodium-ion cells is not limited by scarce resources. However, on average they have a lower energy density than lithium-ion cells.

Due to their high energy density, lithium-ion cells are particularly suitable as an energy source for electric motors in the automotive sector, but also for e-bikes or other applications with high energy requirements, e.g. power tools. This requires lithium-ion cells that are optimized to be loaded with high currents during charging and discharging.

Traditionally, the electrodes, especially of wound composite bodies, are contacted via metal strips (tabs) that are connected to the current collectors by welding and protrude from the front of the wound composite bodies, as is the case, for example, in the 1 and 2 the US 2005/0277019 A1 This can be disadvantageous when high currents occur. Both the tabs mentioned and the electrochemically active components of conventional lithium-ion cells have a limited high-current capability, especially in the charging direction and at low temperatures (< 10 °C). Both electrical and thermal gradients occur. Wound composite bodies are also mechanically disturbed by the tabs, which can lead to unfavorable pressure conditions.

From the WO 2017/215900 A1 Cylindrical lithium-ion cells are known in which a composite body is formed from strip-shaped electrodes and is in the form of a coil. The electrodes each have current collectors loaded with electrode material. Oppositely polarized electrodes are arranged offset from one another within the composite body, so that the longitudinal edges of the current collectors of the positive electrodes emerge from the coil on one side and the longitudinal edges of the current collectors of the negative electrodes emerge from the coil on another side. To electrically contact the current collectors, the cell has contact plates instead of tabs, which sit on the front sides of the coil and are connected to the longitudinal edges of the current collectors by welding. This makes it possible to electrically contact the current collectors and thus also the associated electrodes over their entire length. This significantly reduces the internal resistance within the cell described. The occurrence of large currents can therefore be absorbed much better and heat can also be better dissipated from the coil.

Similar cell constructions can be found in the EP 3916841 A1 , the EP 3916828 A1 , the EP 3916827 A1 , the EP 3916829 A1 , the EP 3916870 A1 , the EP 3916869 A1 , the EP 3916877 A1 , the EP 3965196 A1 and the EP 3916868 A1 .

Lithium-ion cells have not yet been able to establish themselves on the market as starter batteries for vehicles with combustion engines and for some other special applications. Lead batteries are still mostly used for these applications, with the electrodes made of lead or lead dioxide and the electrolyte made of diluted sulfuric acid. Lead batteries can deliver strong currents for short periods of time and are also efficient at low temperatures. In addition, they are comparatively inexpensive to produce.

For environmental reasons, however, a replacement is urgently needed, as lead is extremely toxic. Although an efficient deposit system for batteries exists in many countries, the release of lead during lead ore mining and subsequent processing, as well as during lead recycling, is sometimes difficult to avoid.

task and solution

The object of the present invention was to provide energy storage elements which are not inferior to lead-acid batteries in their performance at low temperatures, but are cheaper than lithium-ion cells and can absorb high currents when charging and release them when discharging.

This object is achieved by the energy storage element with the features of independent claim 1. The battery with the features of claim 13 also contributes to solving the object. Preferred embodiments of the invention are defined in the dependent claims.

Energy storage element according to the invention

1. a. Es umfasst als Elektroden eine Kathode und eine Anode, die Teile eines Verbundkörpers sind, in dem sie, getrennt durch eine Separator- oder Festelektrolytschicht, in der Sequenz Kathode / Separator- oder Festelektrolytschicht / Anode vorliegen,
2. b. die Kathode umfasst einen Kathodenstromkollektor und ein positives Elektrodenmaterial,
3. c. die Anode umfasst einen Anodenstromkollektor und ein negatives Elektrodenmaterial,
4. d. der Kathodenstromkollektor weist
   • - einen Hauptbereich, der beidseitig mit einer Schicht aus dem positiven Elektrodenmaterial beladen ist, sowie
   • - einen freien Randstreifen, der sich entlang eines Rands des Kathodenstromkollektors erstreckt und der nicht mit dem positiven Elektrodenmaterial beladen ist, auf, und/oder der Anodenstromkollektor weist
   • - einen Hauptbereich, der beidseitig mit einer Schicht aus dem negativen Elektrodenmaterial beladen ist, sowie
   • - einen freien Randstreifen, der sich entlang eines Rands des Anodenstromkollektors erstreckt und der nicht mit dem negativen Elektrodenmaterial beladen ist, auf,
5. e. die Kathode und die Anode sind derart ausgebildet und/oder innerhalb des Verbundkörpers derart zueinander angeordnet, dass der freie Randstreifen des Kathodenstromkollektors aus einer Seite des Verbundkörpers und/oder der freie Randstreifen des Anodenstromkollektors aus einer anderen Seite des Verbundkörpers austritt, und
6. f. das Energiespeicherelement umfasst ein erstes Kontaktmetallblech, das mit einem der freien Randstreifen in unmittelbarem Kontakt steht, und/oder ein zweites Kontaktmetallblech, das mit dem anderen der freien Randstreifen in unmittelbarem Kontakt steht, wobei
7. g. die Elektroden mindestens einen lonentyp aus der Gruppe mit Natriumionen, Kaliumionen, Calciumionen, Magnesiumionen und Aluminiumionen umfassen, welche beim Laden und Entladen des sekundären Energiespeicherelements zwischen der Kathode und der Anode ausgetauscht werden.

The energy storage element according to the invention always has the following features a. to g.:

1. a. It comprises as electrodes a cathode and an anode, which are parts of a composite body in which they are separated by a separator or solid electrolyte layer in the sequence cathode / separator or solid electrolyte layer / anode,
2. b. the cathode comprises a cathode current collector and a positive electrode material,
3. c. the anode comprises an anode current collector and a negative electrode material,
4. d. the cathode current collector has
   • - a main area which is loaded on both sides with a layer of the positive electrode material, and
   • - a free edge strip extending along an edge of the cathode current collector and which is not loaded with the positive electrode material, and/or the anode current collector has
   • - a main area which is loaded on both sides with a layer of the negative electrode material, and
   • - a free edge strip extending along an edge of the anode current collector and which is not loaded with the negative electrode material,
5. e. the cathode and the anode are designed and/or arranged relative to one another within the composite body such that the free edge strip of the cathode current collector emerges from one side of the composite body and/or the free edge strip of the anode current collector emerges from another side of the composite body, and
6. f. the energy storage element comprises a first contact metal sheet which is in direct contact with one of the free edge strips and/or a second contact metal sheet which is in direct contact with the other of the free edge strips, wherein
7. g. the electrodes comprise at least one ion type from the group consisting of sodium ions, potassium ions, calcium ions, magnesium ions and aluminium ions, which are exchanged between the cathode and the anode during charging and discharging of the secondary energy storage element.

In its simplest embodiment, the energy storage element according to the invention is a sodium ion cell, a potassium ion cell, a calcium ion cell, a magnesium ion cell or an aluminum ion cell. Among these variants, energy storage elements with sodium ion cell chemistry are particularly preferred according to the invention.

When very high currents and/or low temperatures occur, it is essential to minimize any electrical, thermal and ionic gradients in all electrochemically active components of a cell. Avoiding ohmic losses plays a crucial role. Gradients that are as low as possible across the entire composite body, including the electrolyte space, are crucial for service life and current carrying capacity.

The first and/or the second contact metal sheet ensures a homogeneous electrical and thermal connection of the electrodes of the composite body, in the case of a wound composite body over their entire length, and thus leads to an improvement in performance and an increase in service life. The contact metal sheet makes it possible to dispense with tabs for electrode contact. Accordingly, no mechanical disturbances occur within wound composite bodies that could lead to problems under thermomechanical stress.

Surprisingly, it has been found that the design of the energy storage element according to the invention enables a particularly efficient connection of the electrodes, particularly for the Na-ion system (but also for the other post-lithium systems such as the systems mentioned based on sodium ions, potassium ions, calcium ions, magnesium ions and aluminum ions). High-performance Na-ion materials can thus be charged and discharged at a rate of up to 100 C. In addition, sodium-ion systems in particular can also be built to be resistant to deep discharges.

Energy storage element with wound composite body

1. a. Die Elektroden und die Stromkollektoren sowie die Schichten aus den Elektrodenmaterialien sind bandförmig ausgebildet,
2. b. Es umfasst mindestens einen bandförmigen Separator oder mindestens eine bandförmige Festelektrolytschicht,

1. c. der Verbundkörper liegt in Form eines Wickels vor, in dem die Elektroden und der mindestens eine Separator um eine Wickelachse herum aufgewickelt vorliegen, wobei der Verbundkörper eine erste und eine zweite endständige Stirnseite und einen Wickelmantel umfasst und der freie Randstreifen des Kathodenstromkollektors aus der ersten Stirnseite und/oder der freie Randstreifen des Anodenstromkollektors aus der zweiten Stirnseite austritt,
2. d. Es umfasst ein Gehäuse, insbesondere ein Metallgehäuse, umfassend einen Gehäusemantel oder Seitenwände und an den Stirnseiten einen Boden und einen Deckel, und
3. e. In dem Gehäuse ist der als Wickel ausgebildete Verbundkörper derart ausgerichtet, so dass der Wickelmantel an der Innenseite des Gehäusemantels oder den Seitenwänden anliegt.

The composite body of the energy storage element according to the invention can be designed as a coil or as a stack of electrodes. In the wound variant, it has the following features a. to e.:

1. a. The electrodes and the current collectors as well as the layers of the electrode materials are band-shaped,
2. b. It comprises at least one band-shaped separator or at least one band-shaped solid electrolyte layer,

1. c. the composite body is in the form of a coil in which the electrodes and the at least one separator are wound around a winding axis, wherein the composite body comprises a first and a second terminal end face and a winding jacket and the free edge strip of the cathode current collector emerges from the first end face and/or the free edge strip of the anode current collector emerges from the second end face,
2. d. It comprises a housing, in particular a metal housing, comprising a housing shell or side walls and a base and a cover on the front sides, and
3. e. In the housing, the composite body designed as a winding is aligned such that the winding jacket rests on the inside of the housing jacket or the side walls.

The band-shaped separator forms the separator layer in the composite body.

In this embodiment, the composite body preferably comprises a band-shaped separator or two band-shaped separators, each having a first and a second longitudinal edge and two end pieces.

The winding and the housing are particularly preferably cylindrical. The housing then preferably has a circumferential housing shell and a circular base and cover. In the cylindrical housing, the composite body designed as a cylindrical winding is preferably axially aligned.

Preferably, the electrodes and the at least one separator are wound spirally around the winding axis.

Symmetrical and asymmetrical winding contact

The composite body in the form of the winding can be contacted both symmetrically and asymmetrically.

• - die Kathode und die Anode des Energiespeicherelement derart ausgebildet und/oder innerhalb des Verbundkörpers derart zueinander angeordnet sind, dass der freie Randstreifen des Kathodenstromkollektors aus einer der Stirnseiten des Verbundkörpers und der freie Randstreifen des Anodenstromkollektors aus der anderen der Stirnseiten des Verbundkörpers austritt, und
• - das Energiespeicherelement ein erstes Kontaktmetallblech, das mit einem der freien Randstreifen in unmittelbarem Kontakt steht, und ein zweites Kontaktmetallblech, das mit dem anderen der freien Randstreifen in unmittelbarem Kontakt steht, umfasst.

Symmetrical contacting means that

• - the cathode and the anode of the energy storage element are designed and/or arranged relative to one another within the composite body in such a way that the free edge strip of the cathode current collector emerges from one of the end faces of the composite body and the free edge strip of the anode current collector emerges from the other of the end faces of the composite body, and
• - the energy storage element comprises a first contact metal sheet which is in direct contact with one of the free edge strips and a second contact metal sheet which is in direct contact with the other of the free edge strips.

Both electrodes are thus contacted via contact metal sheets on the two end faces of the winding.

• - die Kathode und die Anode des Energiespeicherelement derart ausgebildet und/oder innerhalb des Verbundkörpers derart zueinander angeordnet sind, dass entweder nur der freie Randstreifen des Kathodenstromkollektors oder nur der freie Randstreifen des Anodenstromkollektors aus einer der Stirnseiten des Verbundkörpers austritt, und
• - das Energiespeicherelement nur ein Kontaktmetallblech umfasst, das mit dem aus dem Verbundkörper austretenden freien Randstreifen des Kathodenstromkollektors oder des Anodenstromkollektors in unmittelbarem Kontakt steht.

Asymmetrical contacting means that

• - the cathode and the anode of the energy storage element are designed and/or arranged relative to one another within the composite body in such a way that either only the free edge strip of the cathode current collector or only the free edge strip of the anode current collector emerges from one of the end faces of the composite body, and
• - the energy storage element comprises only one contact metal sheet which is in direct contact with the free edge strip of the cathode current collector or the anode current collector emerging from the composite body.

In this embodiment, only one of the electrodes is contacted via a contact metal sheet on one of the two end faces of the composite body. At least one metallic conductor strip (tab) is preferably fixed to the current collector of the other electrode, which emerges from the other of the terminal end faces of the composite body.

1. a. Der mindestens eine metallische Ableiterstreifen ist durch Verschweißung mit dem Deckel oder einem durch den Deckel geführten metallischen Pol verbunden, während der aus einer der Stirnseiten austretende freie Randstreifen an den Boden oder an ein unmittelbar auf dem Boden des Gehäuses aufsitzendes Metallblech geschweißt ist (Variante A), oder
2. b. der mindestens eine metallische Ableiterstreifen ist an den Boden geschweißt, während der aus einer der Stirnseiten austretende freie Randstreifen durch Verschweißung mit dem Deckel oder einem durch den Deckel geführten Pol verbunden ist (Variante B). oder

1. c. der mindestens eine metallische Ableiterstreifen ist an den Boden geschweißt, während der aus einer der Stirnseiten austretende freie Randstreifen durch Verschweißung mit einem durch den Deckel geführten Pol oder einem auf dem freien Randstreifen aufsitzenden Metallblech, das elektrisch an den Deckel oder den Pol gekoppelt ist, verbunden ist (Variante C).

In the case of asymmetrical contacting, the energy storage element according to the invention is characterized by one of the following features a. to c.:

1. a. The at least one metallic conductor strip is connected by welding to the cover or to a metallic pole passing through the cover, while the free edge strip emerging from one of the end faces is welded to the base or to a metal sheet sitting directly on the base of the housing (variant A), or
2. b. the at least one metallic conductor strip is welded to the base, while the free edge strip emerging from one of the end faces is connected by welding to the cover or to a pole passing through the cover (variant B). or

1. c. the at least one metallic conductor strip is welded to the base, while the free edge strip emerging from one of the end faces is connected by welding to a pole passed through the cover or to a metal sheet resting on the free edge strip which is electrically coupled to the cover or the pole (variant C).

In variant B, the bottom of the housing acts as a contact metal sheet, which can be particularly advantageous since this embodiment allows optimal heat dissipation of the electrode coupled via the free edge strip.

It is particularly advantageous if the anode current collector is connected directly to the base according to variant B, while the cathode current collector is connected via the tab. The use of the conductor strip on the front side of the winding facing the cover, while simultaneously connecting the anode over the ideally entire longitudinal edge of its current collector, can offer volumetric advantages that are particularly evident in energy-optimized cells. At the same time, positive effects result from the excellent connection of the anode and thus improved performance and service life of the cell according to the invention. The most homogeneous electrical and thermal connection of the anode is particularly advantageous for improved fast charging capability. It should be specifically mentioned in this context that sodium-ion electrolytes generally have higher conductivities than lithium counterparts and therefore have advantages in terms of thick or highly loaded electrodes, fast charging (> 2 C) and performance at low temperatures (< 0 °C).

Preferred developments of the energy storage element with wound composite body

In the case of energy storage elements with a wound composite body, the contact metal sheet(s) preferably lie flat on the end face(s), preferably in such a way that the free edge(s) strips are in contact with the contact metal sheets over their entire length. In practice, however, this is often not achievable.

• a. Das Metallgehäuse umfasst ein becherförmiges, zylindrisch ausgebildetes Gehäuseteil mit einer endständigen, bevorzugt kreisförmige Öffnung und einen Deckel, der die endständige Öffnung des becherförmig ausgebildeten Gehäuseteils verschließt.

Particularly preferably, the energy storage element according to the invention with a wound composite body is characterized by the immediately following feature a.:

• a. The metal housing comprises a cup-shaped, cylindrical housing part with a terminal, preferably circular opening and a cover which closes the terminal opening of the cup-shaped housing part.

In many preferred embodiments, the lid is a lid component made up of several components. For example, the lid can comprise a bursting membrane and/or be equipped with a CID function (CID = Current Interrupt Device).

The cover preferably has a circular circumference and is arranged in the circular opening of the cup-shaped housing part in such a way that the edge rests against the inside of the cup-shaped housing part along a circumferential contact zone, with the edge of the cover being connected to the cup-shaped housing part via a circumferential weld seam. In this case, the two housing parts preferably have the same polarity, i.e. are electrically coupled to either a positive or a negative electrode. In this case, the housing also comprises a pole feedthrough, which serves to electrically contact the electrode that is not electrically connected to the housing.

In an alternative embodiment, an electrically insulating seal is applied to the edge of the lid, which electrically separates the lid from the cup-shaped housing part. In this case, the housing is usually sealed by a crimp closure.

The height of energy storage elements designed as cylindrical round cells is preferably in the range from 50 mm to 150 mm. The diameter of the cylindrical round cells is preferably in the range from 15 mm to 100 mm.

• - Eine Länge im Bereich von 0,3 m bis 25 m
• - Eine Breite im Bereich 30 mm bis 145 mm

The anode current collector, the cathode current collector and the separator or separators or the solid electrolyte layer preferably have the following dimensions in embodiments in which the energy storage element according to the invention is a cylindrical round cell:

• - A length in the range of 0.3 m to 25 m
• - A width in the range 30 mm to 145 mm

In this embodiment, the contact metal sheets preferably have a circular basic shape.

Prismatic design

1. a. Der Verbundkörper liegt in Form eines prismatischen Stapels vor, in dem die Kathode und die Anode gemeinsam mit weiteren Kathoden und Anoden gestapelt vorliegen.
2. b. Die Elektroden und die Stromkollektoren sowie die Schichten aus den Elektrodenmaterialien sind polygonal, insbesondere rechteckig, ausgebildet.
3. c. Es umfasst mindestens einen bandförmigen oder polygonalen, insbesondere rechteckigen, Separator oder mindestens einen bandförmigen oder polygonalen, insbesondere rechteckigen, Festelektrolyten,
4. d. Der Stapel ist von einem prismatischen Gehäuse umschlossen.

In the prismatic embodiment, the energy storage element according to the invention is characterized by the immediately following features a. to c., particularly preferably by the immediately following features a. to d.:

1. a. The composite body is in the form of a prismatic stack in which the cathode and the anode are stacked together with other cathodes and anodes.
2. b. The electrodes and the current collectors as well as the layers of the electrode materials are polygonal, in particular rectangular.
3. c. It comprises at least one band-shaped or polygonal, in particular rectangular, separator or at least one band-shaped or polygonal, in particular rectangular, solid electrolyte,
4. d. The stack is enclosed in a prismatic housing.

In the stack, adjacent oppositely polarized electrodes are always separated from each other by a separator or solid electrolyte layer.

The prismatic housing preferably consists of a cup-shaped housing part with an opening at the end and a cover. The bottom of the cup-shaped housing part and the In this embodiment, lids preferably have a polygonal, particularly preferably a rectangular base. The shape of the terminal opening of the cup-shaped housing part corresponds to the shape of the base and the lid. In addition, the housing comprises several, preferably four, rectangular side parts that connect the base and the lid to one another.

Prismatic shaped cells can also be built as so-called pouch cells. Instead of the metal housing parts, composite films are used, which are formed into the appropriate shape using a deep-drawing process. The current conductors are led outwards via the areas in which the composite films are thermally welded/sealed.

The separator layers can be formed by several separators, each of which is arranged between adjacent electrodes. However, it is also possible for a band-shaped separator to separate the electrodes of the stack from one another. In the case of several separators between the anodes and cathodes, the separators preferably also have a polygonal, in particular rectangular, base area.

In this embodiment, the contact metal sheets preferably have a rectangular basic shape.

1. a. Die freien Randstreifen der Kathodenstromkollektoren der Kathoden des Stapels treten aus einer Seite des Stapels aus und stehen mit dem ersten Kontaktmetallblech in unmittelbarem Kontakt.
2. b. Die freien Randstreifen der Anodenstromkollektoren der Anoden des Stapels treten aus einer anderen Seite des Stapels aus und stehen mit dem zweiten Kontaktmetallblech in unmittelbarem Kontakt.

In some preferred variants of the prismatic embodiment, the energy storage element according to the invention is characterized by at least one of the following features a. and b.:

1. a. The free edge strips of the cathode current collectors of the cathodes of the stack emerge from one side of the stack and are in direct contact with the first contact metal sheet.
2. b. The free edge strips of the anode current collectors of the anodes of the stack emerge from another side of the stack and are in direct contact with the second contact metal sheet.

Preferably, the immediately preceding features a. and b. are implemented in combination with one another.

1. a. Die freien Randstreifen der Kathodenstromkollektoren sind parallel zueinander angeordnet.
2. b. Die freien Randstreifen der Anodenstromkollektoren sind parallel zueinander angeordnet.

In further preferred variants of the prismatic embodiment, the energy storage element according to the invention is characterized by at least one of the immediately following features a. and b.:

1. a. The free edge strips of the cathode current collectors are arranged parallel to each other.
2. b. The free edge strips of the anode current collectors are arranged parallel to each other.

Preferably, the immediately preceding features a. and b. are implemented in combination with one another.

Preferred electrochemical embodiment and electrolyte

1. a. Das Energiespeicherelement ist eine Natrium-Ionen-Zelle.
2. b. Das Energiespeicherelement umfasst eine Natrium-Ionen-Zelle.
3. c. Das Energiespeicherelement umfasst einen der folgenden Elektrolyten:
   • - NaClO₄ gelöst in mindestens einem organischen Lösungsmittel, insbesondere in PC oder in einer Carbonatmischung aus der Gruppe mit EC/DEC/FEC und PC/FEC. Die Konzentration des NaClO₄ im Elektrolyten beträgt bevorzugt 0,3 - 5 M, besonders bevorzugt 0,7 M - 1,7 M. Bei einer Mischung EC/DEC/FEC sind die drei Komponenten bevorzugt in einem Volumenverhältnis im Bereich von 1:2 bis 2:1, insbesondere von 1 : 1 : 0.5, im Elektrolyten enthalten. Im Falle einer Mischung umfassend EC/DEC sind die Komponenten bevorzugt in einem Volumenverhältnis im Bereich von 1:2 bis 2:1 im Elektrolyten enthalten.
   • - NaPF₆ und/oder NaTFSI (Natrium-bis(trifluoromethansulfonyl)imid) gelöst in mindestens einem organischen Lösungsmittel, insbesondere in PC oder in einer Carbonatmischung aus der Gruppe mit EC/DEC/FEC, EC/PC, EC/DEC, FEC/EMC und PC/FEC oder in einer Ethermischung wie THF/mTHF. Die Konzentration des NaPF₆ und/oder des NaTFSI im Elektrolyten beträgt bevorzugt 0,3 - 5 M, besonders bevorzugt 0,7 M - 1,7 M. Bei einer Mischung EC/PC sind die zwei Komponenten bevorzugt in einem Volumenverhältnis im Bereich von 1:2 bis 2:1 im Elektrolyten enthalten. Bei einer Mischung EC/DEC sind die zwei Komponenten bevorzugt in einem Volumenverhältnis im Bereich von 1:2 bis 2:1 im Elektrolyten enthalten. Bei einer Mischung FEC/EMC sind die zwei Komponenten bevorzugt in einem Volumenverhältnis im Bereich von 1:2 bis 2:1, insbesondere in einem Verhältnis von 3:7, im Elektrolyten enthalten. Gegebenenfalls ist im Elektrolyten ein Zusatz von bis zu 10 % FEC enthalten.
   • - NaFSI und/oder NaTFSI und/oder NaTDI gelöst in mindestens einem organischen Lösungsmittel, insbesondere in 1,4-Dioxan (DX) und/oder 1,3-Dioxolan (DOL) und/oder Dimethylether (DME). Die Konzentration des NaFSI und/oder des NaTFSI und/oder des NaTDI im Elektrolyten beträgt bevorzugt 0,3 - 5 M, besonders bevorzugt 0,7 M - 1,7 M.
   • - NaFSI und/oder NaTFSI und/oder NaTDI gelöst in mindestens einem organischen Lösungsmittel, insbesondere in Dimethylcarbonat (DX) und/oder Tris(2,2,2-trifluoroethyl)phosphat (TFP). Die Konzentration des des NaFSI und/oder des NaTFSI und/oder des NaTDI im Elektrolyten beträgt bevorzugt 0,5 - 2,5 M, besonders bevorzugt 1 M - 2 M. Bei einer Mischung EC/PC sind die Komponenten bevorzugt in einem Volumenverhältnis im Bereich von 1:2 bis 2:1 im Elektrolyten enthalten. Besonders bevorzugt sind die flüssigen Komponenten bevorzugt in einem Volumenverhältnis im Bereich von 1:2 bis 2:1 im Elektrolyten enthalten.
   • - NaN(SO₂F)₂ gelöst in mindestens einem organischen Lösungsmittel, insbesondere in 1,4-Dioxan (DX) und/oder 1,3-Dioxolan (DOL) und/oder Dimethylether (DME). Die Konzentration des NaN(SO₂F)₂ im Elektrolyten beträgt bevorzugt 0,3 - 5 M, besonders bevorzugt 0,7 M - 1,7 M. Bei einer Mischung DX/DOL sind die Komponenten bevorzugt in einem Volumenverhältnis im Bereich von 1:2 bis 2:1 im Elektrolyten enthalten.
   • - NaBF₄ gelöst in mindestens einem organischen Lösungsmittel, insbesondere in Tetraethylenglykoldimethylether (TEGDME) und/oder in ACN und/oder in PC und/oder GBL. Die Konzentration des NaBF₄ im Elektrolyten beträgt bevorzugt 0,3 - 5 M, besonders bevorzugt 0,7 M - 1,7 M. Ein Elektrolyt mit NaBF₄ in TEGDME eignet sich insbesondere für Zellen mit Na-Metallanode (siehe unten).

In a further particularly preferred embodiment of the invention, the energy storage element according to the invention is characterized by one of the following features:

1. a. The energy storage element is a sodium ion cell.
2. b. The energy storage element comprises a sodium ion cell.
3. c. The energy storage element comprises one of the following electrolytes:
   • - NaClO ₄ dissolved in at least one organic solvent, in particular in PC or in a carbonate mixture from the group with EC/DEC/FEC and PC/FEC. The concentration of NaClO ₄ in the electrolyte is preferably 0.3 - 5 M, particularly preferably 0.7 M - 1.7 M. In an EC/DEC/FEC mixture, the three components are preferably contained in the electrolyte in a volume ratio in the range from 1:2 to 2:1, in particular 1:1:0.5. In the case of a mixture comprising EC/DEC, the components are preferably contained in the electrolyte in a volume ratio in the range from 1:2 to 2:1.
   • - NaPF ₆ and/or NaTFSI (sodium bis(trifluoromethanesulfonyl)imide) dissolved in at least one organic solvent, in particular in PC or in a carbonate mixture from the group consisting of EC/DEC/FEC, EC/PC, EC/DEC, FEC/EMC and PC/FEC or in an ether mixture such as THF/mTHF. The concentration of NaPF ₆ and/or NaTFSI in the electrolyte is preferably 0.3 - 5 M, particularly preferably 0.7 M - 1.7 M. In an EC/PC mixture, the two components are preferably contained in the electrolyte in a volume ratio in the range of 1:2 to 2:1. In an EC/DEC mixture, the two components are preferably contained in the electrolyte in a volume ratio in the range of 1:2 to 2:1. In an FEC/EMC mixture, the two components are preferably contained in the electrolyte in a volume ratio in the range of 1:2 to 2:1, in particular in a ratio of 3:7. If appropriate, the electrolyte contains an addition of up to 10% FEC.
   • - NaFSI and/or NaTFSI and/or NaTDI dissolved in at least one organic solvent, in particular in 1,4-dioxane (DX) and/or 1,3-dioxolane (DOL) and/or dimethyl ether (DME). The concentration of the NaFSI and/or the NaTFSI and/or the NaTDI in the electrolyte is preferably 0.3 - 5 M, particularly preferably 0.7 M - 1.7 M.
   • - NaFSI and/or NaTFSI and/or NaTDI dissolved in at least one organic solvent, in particular in dimethyl carbonate (DX) and/or tris(2,2,2-trifluoroethyl)phosphate (TFP). The concentration of the NaFSI and/or the NaTFSI and/or the NaTDI in the electrolyte is preferably 0.5 - 2.5 M, particularly preferably 1 M - 2 M. In an EC/PC mixture, the components are preferably contained in the electrolyte in a volume ratio in the range of 1:2 to 2:1. The liquid components are particularly preferably contained in the electrolyte in a volume ratio in the range of 1:2 to 2:1.
   • - NaN(SO ₂ F) ₂ dissolved in at least one organic solvent, in particular in 1,4-dioxane (DX) and/or 1,3-dioxolane (DOL) and/or dimethyl ether (DME). The concentration of NaN(SO ₂ F) ₂ in the electrolyte is preferably 0.3 - 5 M, particularly preferably 0.7 M - 1.7 M. In a DX/DOL mixture, the components are preferably contained in the electrolyte in a volume ratio in the range from 1:2 to 2:1.
   • - NaBF ₄ dissolved in at least one organic solvent, in particular in tetraethylene glycol dimethyl ether (TEGDME) and/or in ACN and/or in PC and/or GBL. The concentration of NaBF ₄ in the electrolyte is preferably 0.3 - 5 M, particularly preferably 0.7 M - 1.7 M. An electrolyte with NaBF ₄ in TEGDME is particularly suitable for cells with a Na metal anode (see below).

Particularly preferably, features a. and c. as well as b. and c. are implemented in combination with one another.

Feature a. relates in particular to the described embodiment of the energy storage element according to the invention as a cylindrical round cell. In this embodiment, the energy storage element preferably comprises exactly one electrochemical cell.

Feature b. relates in particular to the described prismatic embodiment of the energy storage element according to the invention. In this embodiment, the energy storage element can also comprise more than one electrochemical cell.

• Bevorzugte Lösungsmittel sind:
  • - Carbonate: Propylencarbonat (PC), Ethylencarbonat-Propylencarbonat (EC-PC), Propylencarbonat-Dimethylcarbonat-Ethylmethylcarbonat (PC-DMC-EMC), Ethylencarbonat-Diethylcarbonat (EC-DEC), Ethylencarbonat-Dimethylcarbonat (EC-DMC), Ethylencarbonat-Ethylmethylcarbonat (EC-EMC), Ethylencarbonat-Dimethylcarbonat-Ethylmethylcarbonat (EC-DMC-EMC), Ethylencarbonat-Dimethylcarbonat-Diethylcarbonat (EC-DMC-DEC)
  • - Ether: Tetrahydrofuran (THE), 2-Methyltetrahydrofuran, Dimethylether (DME), 1,4-dioxane (DX), 1,3-dioxolane (DOL), Diethylenglykoldimethylether (DEGDME), Tetraethylenglykoldimethylether (TEGDME)
  • - Nitrile: Acetonitril (ACN), Adiponitril (AON), y-Butyrolactone (GBL)

Preferably, the energy storage element according to the invention based on sodium ions further comprises an electrolyte which comprises at least one of the following solvents and at least one of the following conductive salts:

• Preferred solvents are:
  • - Carbonates: Propylene Carbonate (PC), Ethylene Carbonate-Propylene Carbonate (EC-PC), Propylene Carbonate-Dimethyl Carbonate-Ethyl Methyl Carbonate (PC-DMC-EMC), Ethylene Carbonate-Diethyl Carbonate (EC-DEC), Ethylene Carbonate-Dimethyl Carbonate (EC-DMC), Ethylene Carbonate-Ethyl Methyl Carbonate (EC-EMC), Ethylene Carbonate-Dimethyl Carbonate-Ethyl Methyl Carbonate (EC-DMC-EMC), Ethylene Carbonate-Dimethyl Carbonate -Diethyl carbonate (EC-DMC-DEC)
  • - Ethers: Tetrahydrofuran (THE), 2-methyltetrahydrofuran, dimethyl ether (DME), 1,4-dioxane (DX), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether (DEGDME), tetraethylene glycol dimethyl ether (TEGDME)
  • - Nitriles: Acetonitrile (ACN), Adiponitrile (AON), y-Butyrolactone (GBL)

Trimethyl phosphate (TMP) and tris(2,2,2-trifluoroethyl) phosphate (TFP) are also possible.

• NaPF₆, Natrium-difluoro(oxalato)borat (NaBOB), NaBF₄, Natriumbis(fluorosulfonyl)imid (NaFSI), Natrium-2-trifluoromethyl-4,5-dicyanoimidazol (NaTDI), Natrium-bis(trifluoromethan-sulfonyl)imid (NaTFSI), NaAsF₆, NaBF₄, NaClO₄, NaB(C₂O₄)₂, NaP(C₆H₄O₂)₃; NaCF₃SO₃, Natriumtriflat (NaTf) und Et₄NBF₄.

Preferred conductive salts are:

• NaPF ₆ , sodium difluoro(oxalato)borate (NaBOB), NaBF ₄ , sodium bis(fluorosulfonyl)imide (NaFSI), sodium 2-trifluoromethyl-4,5-dicyanoimidazole (NaTDI), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), NaAsF ₆ , NaBF ₄ , NaClO ₄ , NaB(C ₂ O ₄ ) ₂ , NaP(C ₆ H ₄ O ₂ ) ₃ ; NaCF ₃ SO ₃ , sodium triflate (NaTf) and Et ₄ NBF ₄ .

Like the solvents, the conductive salts can also be used as a mixture of two or more conductive salts.

• Fluoroethylencarbonat (FEC), Transdifluoroethylencarbonat (DFEC), Ethylensulfit (ES), Vinylencarbonat (VC), Bis(2,2,2-trifluoroethyl)ether (BTFE), Natrium-2-trifluoromethyl-4,5-dicya-noimidazol (NaTDI), Natriumbis(fluorosulfonyl)imide (NaFSI), Aluminumchlorid (AlCl₃), Ethylensulfat (DTD), Natriumdifluorophosphat (NaPO₂F₂), Natriumdifluoro(oxalato)borat (NaODFB), Natriumdifluorobisoxalatophosphat (NaDFOP) und Tris(trimethylsilyl)borat (TMSB).

In preferred embodiments, additives can be added to the electrolyte. Examples of preferred additives, particularly for stabilization, are the following:

• Fluoroethylene carbonate (FEC), transdifluoroethylene carbonate (DFEC), ethylene sulfite (ES), vinylene carbonate (VC), bis(2,2,2-trifluoroethyl)ether (BTFE), sodium 2-trifluoromethyl-4,5-dicya-noimidazole (NaTDI), sodium bis(fluorosulfonyl)imide (NaFSI), aluminum chloride (AlCl ₃ ), ethylene sulfate (DTD), sodium difluorophosphate (NaPO ₂ F. ₂ ), sodium difluoro(oxalato)borate (NaODFB), sodium difluorobisoxalatophosphate (NaDFOP) and tris(trimethylsilyl)borate (TMSB).

Instead of liquid electrolytes with the aforementioned conducting salts, ionic liquids can also be used, e.g. 0.8 mol/l sodium bis(fluorosulfonyl)imide (Na-TFSI) in 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide (PMPyrr-TFSI).

Sodium polymer electrolytes are also possible as an alternative, for example polymer electrolytes based on polyethylene oxide (PEO) or on polyvinylidene difluoride-cohexafluoropropylene, such as P(EO) ₈ NaCF ₃ SO ₃ or hydroxyethylcellulose-polyethylene oxide.

Instead of liquid electrolytes based on organic solvents, aqueous sodium electrolytes with anions from the group OH ^- , NO ₃ ^- , Cl ^- and SO ₄ ^2- can be used in special applications, or aqueous solutions of NaFSI, NaTDI or NaTFSI.

Preferred embodiments of the electrode materials

• - Kohlenstoff, besonders präferiert Hardcarbon (rein oder mit Stickstoff- und/oder Phosphor-Dotierung) oder Softcarbon oder Graphene-basierte Materialien (mit N-dotierung); Kohlenstoffnanotubes, Graphit
• - Phosphor oder Schwefel (Konversionsanode)
• - Polyanionen: Na₂Ti₃O₇, Na₃Ti₂(PO₄)₃, TiP₂O₇, TiNb₂O₇, Na-Ti-(PO₄)₃, Na-V-(PO₄)₃ oder Na-M-PO₄-P₂O₇ mit M= V, Ti, Fe, Co, Ni, Mn, oder Mischungen aus 3d-Übergangsmetallen und zugesetzten Dotierelementen wie z.B. Al, Cu, Zn
• - Na₄M₃(PO₄)₂(P₂O₇) mit M= Na, Zn, Al, Mg, oder Ca
• - Sn- oder Sb-basierte Materialien wie Sn(Na₁₅Sn₄), Sb(Na₃Sb), SnO₂, Sb₂O₃
• - Preussisch Blau: Na-arme Variante (für Systeme mit wässrigem Elektrolyt)
• - Übergangsmetalloxide: V₂O₃, MnO₂, TiO₂, Nb₂O₃, Fe₂O₃, Na₂Ti₃O₇, NaCrTiO₄, Na₄Ti₅O₁₂
• - MXene mit M= Ti, V, Cr, Mo oder Nb und A = Al, Si, und Ga sowie X= C und/oder N, z.B. Ti₃C₂
• - Organisch: z.B. Na-Terephthalate (Na₂C₈H₂O₄)

The negative electrode material of an energy storage element according to the invention based on sodium ions is preferably at least one of the following materials:

• - Carbon, especially preferred hard carbon (pure or with nitrogen and/or phosphorus doping) or soft carbon or graphene-based materials (with N-doping); carbon nanotubes, graphite
• - Phosphorus or sulfur (conversion anode)
• - Polyanions: Na ₂ Ti ₃ O ₇ , Na ₃ Ti ₂ (PO ₄ ) ₃ , TiP ₂ O ₇ , TiNb ₂ O ₇ , Na-Ti-(PO ₄ ) ₃ , Na-V-(PO ₄ ) ₃ or Na-M-PO ₄ -P ₂ O ₇ with M= V, Ti, Fe, Co, Ni, Mn, or mixtures of 3d transition metals and added doping elements such as Al, Cu, Zn
• - Na ₄ M ₃ (PO ₄ ) ₂ (P ₂ O ₇ ) with M = Na, Zn, Al, Mg, or Ca
• - Sn- or Sb-based materials such as Sn(Na ₁₅ Sn ₄ ), Sb(Na ₃ Sb), SnO ₂ , Sb ₂ O ₃
• - Prussian Blue: Na-poor variant (for systems with aqueous electrolyte)
• - Transition metal oxides: V ₂ O ₃ , MnO ₂ , TiO ₂ , Nb ₂ O ₃ , Fe ₂ O ₃ , Na ₂ Ti ₃ O ₇ , NaCrTiO ₄ , Na ₄ Ti ₅ O ₁₂
• - MXene with M= Ti, V, Cr, Mo or Nb and A = Al, Si, and Ga and X= C and/or N, e.g. Ti ₃ C ₂
• - Organic: e.g. Na terephthalates (Na ₂ C ₈ H ₂ O ₄ )

An exemplary overview of suitable anode materials can also be found in the publication by Zhang et al., “SODIUM-ION BATTERY ANODES: STATUS AND FUTURE TRENDS”, EnergyChem 1 , 100012 (2019) from 2019 in Table 2 on page 19.

Alternatively, a Na metal anode can also be used on the anode side. The metallic sodium is preferably embedded in a porous, electrically conductive matrix structure with good Na wettability. Of great importance here are minimal electrical, thermal and mechanical gradients, which are made possible in the cell according to the invention by the design with front-side contacting of the electrode winding.

• - Polyanionen: NaFePO₄ (Triphylit-Typ), Na₂Fe-(P₂O₇), Na₄Fe₃(PO₄)₂(P₂O₇), Na₂FePO₄F, Na/Na₂[Fe_1/2Mn_1/2]PO₄F, Na₃V₂(PO₄)₂F₃, Na₃V₂(PO₄)₃, Na₄(CoM-nNi)₃(PO₄)₂P₂O7, NaCoPO₄, Na₂CoPO₄F
• - Silikate: Na₂MnSiO₄, Na₂FeSiO₄
• - Preussisch Blau / Weiss: Preussisch Blau (PB) existiert in Form von A_xFe[Fe(CN)₆]_1-y*nH₂O mit A = Alkalimetall und 0 < x < 2 und y < 1; Preussisch Weiss (Na ~ 2) in Form von Na₂Fe[Fe(CN)₆], KFe₂(CN)₆, MnFe(CN)₆ und Fe₂(CN)₆
• - Schichtoxide: NaCoO₂, NaFeO₂, NaNiO₂, NaCrO₂, NaVO₂, NaTiO₂, Na(FeCo)O₂, Na(NiFeCo)₃O₂, Na(NiFeMn)O₂, and Na(NiFeCoMn)O₂, Na(NiMnCo)O₂

The positive electrode material of an energy storage element according to the invention based on sodium ions is preferably at least one of the following materials:

• - Polyanions: NaFePO ₄ (triphylite type), Na ₂ Fe-(P ₂ O ₇ ), Na ₄ Fe ₃ (PO ₄ ) ₂ (P ₂ O ₇ ), Na ₂ FePO ₄ F, Na/Na ₂ [Fe _1/2 Mn _1/2 ]PO ₄ F, Na ₃ V ₂ (PO ₄ ) ₂ F ₃ , Na ₃ V ₂ (PO ₄ ) ₃ , Na ₄ (CoM-nNi) ₃ (PO ₄ ) ₂ P ₂ O7, NaCoPO ₄ , Na ₂ CoPO ₄ F
• - Silicates: Na ₂ MnSiO ₄ , Na ₂ FeSiO ₄
• - Prussian Blue / White: Prussian Blue (PB) exists in the form of A _x Fe[Fe(CN) ₆ ] _1-y *nH ₂ O with A = alkali metal and 0 < x < 2 and y <1; Prussian White (Na ~ 2) in the form of Na ₂ Fe[Fe(CN) ₆ ], KFe ₂ (CN) ₆ , MnFe(CN) ₆ and Fe ₂ (CN) ₆
• - Layered oxides: NaCoO ₂ , NaFeO ₂ , NaNiO ₂ , NaCrO ₂ , NaVO ₂ , NaTiO ₂ , Na(FeCo)O ₂ , Na(NiFeCo) ₃ O ₂ , Na(NiFeMn)O ₂ , and Na(NiFeCoMn)O ₂ , Na(NiMnCo)O ₂

Blends of the above-mentioned positive electrode materials can also be used.

In addition, the electrodes of an energy storage element according to the invention preferably contain an electrode binder and/or an additive to improve the electrical conductivity. The active materials are preferably embedded in a matrix made of the electrode binder, with the active materials preferably being used in particulate form and neighboring particles in the matrix preferably being in direct contact with one another. Conductive agents serve to increase the electrical conductivity of the electrodes. Common electrode binders are based, for example, on polyvinylidene fluoride (PVDF), (Na) polyacrylate, styrene-butadiene rubber, (Na) alginate or carboxymethyl cellulose or mixtures of different binders. Common conductive agents are carbon black, fine graphite, carbon fibers, carbon nanotubes and metal powder.

The following material combinations are particularly preferred for sodium ion-based energy storage elements - Positive electrode: Na ₃ V ₂ (PO ₄ ) ₃ Negative electrode: Hard Carbon Electrolyte: Preferably NaPF ₆ in EC:PC:DMC (45:45:10 vol.-%) - Positive electrode: Na _2/3 (Ni _1/3 Mn _2/3 )O ₂ Negative electrode: Hard Carbon - Positive electrode: Na ₂ Fe[Fe(CN) ₆ ] Negative electrode: Hard Carbon Electrolyte: Preferably NaPF ₆ in EC:PC

ion depot

The function of a sodium, potassium, calcium, magnesium or aluminum ion cell is based on there being enough mobile ions (in the case of a sodium ion cell, for example, mobile sodium ions) available to balance out the electrical current drawn by migrating between the anode and the cathode or the negative electrode and the positive electrode. In the context of this application, mobile ions are understood to mean that the ions are available for storage and removal processes in the electrodes during the discharge and charge processes of the energy storage element according to the invention or can be activated for this purpose. In the course of the discharge and charge processes, e.g. of a sodium ion cell, losses of mobile sodium occur over time. These losses occur as a result of various, usually unavoidable side reactions. Losses of mobile sodium occur as early as the first charge and discharge cycle of a sodium ion cell. During this first charge and discharge cycle, a coating layer usually forms on the surface of the electrochemically active components on the negative electrode. This coating layer is called Solid Elect rolyte interphase (SEI) and usually consists mainly of electrolyte decomposition products and a certain amount of sodium that is firmly bound in this layer.

1. a. Das Energiespeicherelement umfasst ein nicht von der positiven und/oder der negativen Elektrode umfasstes Depot an Natrium oder einem natriumhaltigen Material, mit dem Verluste an mobilem Natrium während des Betriebs ausgeglichen werden können.
2. b. Das Depot steht in Kontakt mit dem Elektrolyten des Energiespeicherelements.

In order to compensate for these losses, the sodium ion-based energy storage element according to the invention is characterized in preferred embodiments by at least one of the following features a. and b.:

1. a. The energy storage element comprises a reservoir of sodium or a sodium-containing material not included in the positive and/or negative electrodes, which can compensate for losses of mobile sodium during operation.
2. b. The depot is in contact with the electrolyte of the energy storage element.

It is particularly preferred that the immediately preceding features a. and b. are implemented in combination with one another.

Particularly suitable as sodium-containing materials are, for example, Na ₃ N, Na ₂ C ₂ O ₄ , Na ₂ S, Na ₂ C ₄ O ₄ , Na ₂ C ₆ O ₆ , EDTA-4Na, DPTA-5Na, Na ₃ P or C ₁₂ H ₉ Na (sodium biphenyl). These materials can, for example, be added to the electrode active material. An additional Na source leads to higher capacity or longer cycle life.

It is also conceivable that the electrodes are precharged with an excess of sodium ions.

The same applies to embodiments of the energy storage element according to the invention based on potassium, calcium, magnesium or aluminum ions.

Preferred embodiment of a sodium metal anode

As mentioned above, a Na-metal anode can also be used on the anode side, in which the metallic sodium is preferably embedded in an electrically conductive matrix structure.

1. a. Die Anode umfasst eine Matrix mit Vertiefungen und/oder Poren, in die metallisches Natrium eingelagert ist.
2. b. Die Matrix haftet auf der Oberfläche des Anodenstromkollektors.
3. c. Die Matrix umfasst Kohlenstoffpartikel und einen Binder.
4. d. Die Matrix umfasst Leitmittel und/oder Füllstoffe.
5. e. Bei der Matrix handelt es sich um eine aufgeraute Oberfläche des Anodenstromkollektors.

In a further development, it may be preferred that the energy storage element according to the invention is characterized by at least one of the following features:

1. a. The anode comprises a matrix with depressions and/or pores in which metallic sodium is embedded.
2. b. The matrix adheres to the surface of the anode current collector.
3. c. The matrix comprises carbon particles and a binder.
4. d. The matrix comprises conductive agents and/or fillers.
5. e. The matrix is a roughened surface of the anode current collector.

It is particularly preferred that the immediately preceding features a. to d. or a. and d. are implemented in combination with one another.

The carbon particles, conductive agents or fillers are, for example, hard carbon, activated carbon, conductive graphite, soot, carbon nanotubes, graphene or graphene oxide, or finely dispersed metals such as Ag, Cu, Al, Ni or Pt. For example, the carbon particles can comprise 20-80 wt.% hard carbon and 80-20 wt.% soot as well as 0-10 wt.% silver, whereby it is preferred that the weight proportions of the components add up to 100 wt.%.

The binder can basically be any binder that is also suitable for the production of composite electrodes for lithium-ion batteries. Examples of suitable binders are polyvinylidene fluoride (PVDF) or another polymer, such as carboxymethyl cellulose or a derivative based on it.

The carbon-based matrix may comprise doping elements such as boron, oxygen, fluorine or nitrogen.

The carbon-based matrix is preferably 500 nm to 250 µm thick.

The surface of the anode current collector can be roughened, for example, by laser treatment.

1. a. Die Anode umfasst an Stelle der Matrix eine Nukleationsschicht, in die metallisches Natrium eingelagert ist und/oder auf der metallisches Natrium abgeschieden ist.
2. b. Die Nukleationsschicht besteht im Wesentlichen aus mindestens einem Material aus der Gruppe mit Zinn, Silber, Gold, Germanium, Kohlenstoff, Platin, Zink, Aluminium, Magnesium und Silizium.
3. c. Die Nukleationsschicht wurde mittels PVD (physical vapor deposition) oder CVD (chemical vapor deposition) auf der Oberfläche des Anodenstromkollektors abgeschieden.

Furthermore, it may be preferred that the energy storage element according to the invention is characterized by at least one of the following features:

1. a. Instead of the matrix, the anode comprises a nucleation layer in which metallic sodium is embedded and/or on which metallic sodium is deposited.
2. b. The nucleation layer consists essentially of at least one material from the group consisting of tin, silver, gold, germanium, carbon, platinum, zinc, aluminium, magnesium and silicon.
3. c. The nucleation layer was deposited on the surface of the anode current collector by PVD (physical vapor deposition) or CVD (chemical vapor deposition).

The nucleation layer of tin, silver, gold, germanium and/or carbon facilitates the deposition of sodium. Carbon, silver, gold, platinum, zinc, aluminum, magnesium, tin and silicon reduce the overvoltage.

The nucleation layer can also contain doping elements, such as boron, oxygen, fluorine or nitrogen.

The nucleation layer is preferably 100 nm to 50 µm thick.

It is preferred that the matrix and/or the nucleation layer account for less than 30% by weight, preferably less than 5% by weight, of the dry weight of the negative electrode.

To manufacture an electrode with the matrix or the nucleation layer, an anode current collector with the matrix or the nucleation layer is preferably provided, but free of metallic sodium. The sodium is preferably deposited in and/or on the matrix or the nucleation layer during a first charging process. The required sodium is preferably supplied via the cathode. For example, Na ₃ V ₂ (PO ₄ ) ₃ can be used as the positive electrode material. Alternatively, the sodium deposition can also be carried out by pre-sodium deposition. This procedure prevents dendritic growth. It also ensures that there is no undesirable excess of sodium in the electrodes.

It may be expedient to provide a degassing option during the first charging process so that no excessive pressure builds up in the housing of the energy storage element according to the invention.

Particularly preferably, a ratio of anode capacity to cathode capacity is set in the range of 0.7 to 1.2.

• Besonders bevorzugt ist die Nukleationsschicht und/oder die Matrix mit einer Deckschicht abgedeckt. Die negative Elektrode umfasst somit bevorzugt die folgende Schichtsequenz:
  • - Metallischer Stromkollektor
  • - Matrix oder Nukleationsschicht
  • - Deckschicht

The energy storage element according to the invention is particularly preferably characterized by at least one of the following features:

• Particularly preferably, the nucleation layer and/or the matrix is covered with a cover layer. The negative electrode thus preferably comprises the following layer sequence:
  • - Metallic current collector
  • - matrix or nucleation layer
  • - top layer

The matrix or nucleation layer is thus arranged between the cover layer and the current collector.

The cover layer preferably has a thickness in the range of 300 nm to 30 µm.

The cover layer is preferably formed from a ceramic material or comprises such a ceramic material. The ceramic material is preferably aluminum oxide (Al ₂ O ₃ ), aluminum hydroxide or aluminum oxide hydroxide (AIOOH), silicon oxide (SiO _x with x in the range of >1 and ≤ 2), titanium oxide (TiO ₂ ), titanium nitride (TiN), titanium aluminum nitride (TiAIN) or titanium carbonitride (TiCN).

In further possible preferred embodiments, the cover layer is formed from a super ion conductor of the chemical formula Na _1+x Zr ₂ Si _x P _3-x O ₁₂ (where 0 < x < 3) or comprises such an ion conductor.

In further possible preferred embodiments, the cover layer is formed from a polymer, in particular a polysiloxane, a polyethylene oxide, a perfluoropolyether or a polyacrylonitrile, or comprises such a polymer.

If the cover layer comprises the ceramic material, in preferred embodiments it also comprises a binder. This binder can basically be a binder that is also suitable as a binder for the active material, for example carboxymethyl cellulose.

Preferred embodiments of the separator and the solid electrolyte

The separator or separators are preferably made of electrically insulating plastic films. It is preferred that the separators can be penetrated by the electrolyte. For this purpose, the plastic films used can have micropores, for example. The film can consist of a polyolefin or a polyether ketone, for example. Nonwovens and fabrics made of plastic materials or other electrically insulating surface structures can also be used as separators. Separators that have a thickness in the range of 5 µm to 50 µm are preferably used.

Separators made of cellulose-based materials can also be used. These offer good wettability and high temperature stability.

In particular in the case of prismatic embodiments of the energy storage element, the separator or separators of the composite may also be one or more layers of a solid electrolyte.

The solid electrolyte can, for example, be a polymer solid electrolyte based on a polymer-conducting salt complex that is present in a single phase without any liquid component. A polymer solid electrolyte can have, for example, polyacrylic acid (PAA), polyethylene glycol (PEG) or polymethyl methacrylate (PMMA), in particular polyethylene oxide (PEO) as a polymer matrix. In the case of a sodium ion cell, sodium conducting salts such as sodium bis(trifluoromethane)sulfonylimide (NaTFSI), sodium hexafluorophosphate (NaPF ₆ ) and sodium tetrafluoroborate (NaBF ₄ ) can be dissolved in these.

Ceramic reinforcement of the separator

1. a. Die Seite des Verbundkörpers, aus der der freie Randstreifen des Kathodenstromkollektors oder der freie Randstreifen des Anodenstromkollektors austritt, wird von einem Rand des Separators, bei einem Energiespeicherelement mit gewickeltem Verbundkörper insbesondere einem Längsrand des Separators, gebildet.
2. b. Der Rand oder Längsrand des Separators, der die Seite, insbesondere die Stirnseite, bildet, ist keramisch verstärkt.

Further preferred embodiments of the separator may be useful in individual cases. The energy storage element according to the invention is preferably further characterized by at least one of the immediately following features a. and b.:

1. a. The side of the composite body from which the free edge strip of the cathode current collector or the free edge strip of the anode current collector emerges is formed by an edge of the separator, in the case of an energy storage element with a wound composite body, in particular a longitudinal edge of the separator.
2. b. The edge or longitudinal edge of the separator forming the side, in particular the front side, is ceramically reinforced.

1. a. Die keramische Verstärkung wird durch mindestens ein partikuläres keramisches Material, insbesondere mindestens ein partikuläres keramisches Füllmaterial in dem Separator, bewirkt.

In a preferred development, the energy storage element according to the invention is characterized by the immediately following feature a.:

1. a. The ceramic reinforcement is effected by at least one particulate ceramic material, in particular at least one particulate ceramic filler material in the separator.

The separator can therefore preferably be an electrically insulating plastic film in which the particulate filling material is embedded. It is preferred that the plastic film can be penetrated by the electrolyte, for example because it has micropores. The film can be made of a polyolefin or a polyether ketone, for example. As mentioned, fleeces and Fabrics made of such plastic materials can be used. These can also be preferred in individual cases.

The proportion of particulate filler material in the separator is preferably at least 40% by weight, particularly preferably at least 60% by weight.

1. a. Die keramische Verstärkung wird durch mindestens ein partikuläres keramisches Material bewirkt, das als Beschichtung auf einer Oberfläche des oder der Separatoren vorliegt.

In a further preferred development, the energy storage element according to the invention is characterized by the immediately following feature a.:

1. a. The ceramic reinforcement is provided by at least one particulate ceramic material present as a coating on a surface of the separator(s).

The separator can therefore preferably also be a plastic film or a fleece or a fabric or another electrically insulating surface structure which is coated with a ceramic material.

In some embodiments, only one side of the sheet-like structure, in particular the plastic film, is coated with the ceramic material. In further embodiments, the sheet-like structure, in particular the plastic film, is preferably coated on both sides with the ceramic material.

Optionally, it may also be preferred that the separators used comprise a ceramic material as a filler material and the same or a different ceramic material as a coating.

1. a. Das mindestens eine keramische Material / Füllmaterial ist oder umfasst ein elektrisch isolierendes Material.
2. b. Das mindestens eine keramische Material / Füllmaterial ist oder umfasst mindestens ein Material aus der Gruppe mit glaskeramischem Material und Glas.
3. c. Das mindestens eine keramische Material / Füllmaterial ist oder umfasst ein Natriumionen leitendes keramisches Material, beispielsweise Na₃AlO₄*Na₄SiO₄ oder NaAlSi₂O₆. oder β-Al₂O₃ oder ein NASICON-Material wie z.B. Na₃Zr₂Si₂PO₁₂.
4. d. Das mindestens eine keramische Material / Füllmaterial ist oder umfasst ein oxidisches Material, insbesondere ein Metalloxid.
5. e. Bei dem keramischen oder dem oxidischen Material handelt es sich um Aluminiumoxid (Al₂O₃), um Siliziumoxid (SiO_x), insbesondere um Siliziumdioxid (SiO₂), um Titanoxid (TiO₂), um Titannitrid (TiN), um Titanaluminiumnitrid (TiAIN), um ein Siliziumoxid, insbesondere Siliziumdioxid (SiO₂) oder um Titancarbonitrid (TiCN).

In further possible preferred developments, the energy storage element according to the invention is characterized by at least one of the following features a. to e.:

1. a. The at least one ceramic material/filler material is or comprises an electrically insulating material.
2. b. The at least one ceramic material/filling material is or comprises at least one material from the group consisting of glass-ceramic material and glass.
3. c. The at least one ceramic material / filler material is or comprises a sodium ion conductive ceramic material, for example Na ₃ AlO ₄ *Na ₄ SiO ₄ or NaAlSi ₂ O ₆ . or β-Al ₂ O ₃ or a NASICON material such as Na ₃ Zr ₂ Si ₂ PO ₁₂ .
4. d. The at least one ceramic material/filler material is or comprises an oxidic material, in particular a metal oxide.
5. e. The ceramic or oxide material is aluminium oxide (Al ₂ O ₃ ), silicon oxide (SiO _x ), in particular silicon dioxide (SiO ₂ ), titanium oxide (TiO ₂ ), titanium nitride (TiN), titanium aluminium nitride (TiAIN), a silicon oxide, in particular silicon dioxide (SiO ₂ ) or titanium carbonitride (TiCN).

It is particularly preferred that the immediately preceding features a. to c. or the immediately preceding features a. and b. and d. or the immediately preceding features a. and b. and e. are implemented in combination with one another.

Among the materials mentioned, aluminum oxide (Al ₂ O ₃ ), aluminum hydroxide (Al(OH) _{3 )} , aluminum oxide hydroxide (AIOOH), titanium oxide (TiO ₂ ) and silicon dioxide (SiO ₂ ) are particularly preferred as coating materials.

1. a. Der Separator oder die Separatoren umfassen das mindestens eine keramische Material lediglich bereichsweise.
2. b. Der Separator oder die Separatoren weisen entlang des die erste Seite, insbesondere die erste Stirnseite, bildenden Rands einen Randstreifen auf, in dem sie das mindestens eine keramische Material als Beschichtung und/oder als partikuläres Füllmaterial umfassen.

In further possible preferred developments, the energy storage element according to the invention is characterized by at least one of the immediately following features a. and b.:

1. a. The separator or separators comprise the at least one ceramic material only in regions.
2. b. The separator or separators have an edge strip along the edge forming the first side, in particular the first end face, in which they comprise the at least one ceramic material as a coating and/or as a particulate filler material.

It is particularly preferred that the immediately preceding features a. and b. are implemented in combination with one another.

It is by no means absolutely necessary for the separator to comprise the ceramic material in a homogeneous distribution or to be evenly and everywhere coated with the material. Rather, it may even be preferred for the separator to be free of the ceramic material in certain areas, for example in the main area mentioned. In this area, increased thermal resistance of the separator is not as necessary as at the edges of the separator. In addition, the ceramic material, particularly in this area, can contribute to an unwanted increase in the internal resistance of the energy storage element according to the invention.

In many embodiments, however, the separator is preferably reinforced or coated with the ceramic material over its entire surface - i.e. also between the anode and cathode.

The frontal electrode areas without active material coating could be completely or partially coated with ceramic materials in order to reduce the risk of short circuits.

Further details on coatings of separators with ceramic materials are available in the WO 2021/255238 A1 to be taken.

Preferred embodiments of the current collectors

The current collectors of the electrodes of the energy storage element according to the invention serve to electrically contact electrochemically active components contained in the respective electrode material over as large an area as possible. The current collectors preferably consist of a metal or are at least metallized on the surface.

Particularly in the case of an energy storage element according to the invention based on sodium ions, aluminum or an aluminum alloy are suitable as metallic materials for both the anode current collector and the cathode current collector. Sodium ion systems that have current collectors made of aluminum or an aluminum alloy on both the anode and cathode sides have proven to be particularly resistant to the effects of deep discharges.

Suitable aluminum alloys for the cathode current collector are, for example, Al alloys of type 1235, 1050, 1060, 1070, 3003, 5052, Mg3, Mg212 (series 3000) and GM55. Also suitable are AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, Al-CuTiMg and AlMg. The aluminum content of said alloys is preferably above 99.5%.

Preferably, the anode current collector and/or the cathode current collector are each a strip-shaped metal foil with a thickness in the range of 4 µm to 30 µm.

In addition to films, other strip-shaped substrates such as metallic or metallized fleeces or open-pored metallic foams or expanded metals can also be used as current collectors.

The current collectors are preferably loaded on both sides with the respective electrode material.

Edge reinforcement of the current collector(s)

1. a. In dem freien Randstreifen des Kathodenstromkollektors und/oder in dem freien Randstreifen des Anodenstromkollektors ist die Oberfläche des Kathodenstromkollektors und/oder des Anodenstromkollektors mit einem Stützmaterial beschichtet, das thermisch beständiger als die damit beschichtete Oberfläche ist.
2. b. Bei dem nichtmetallischen Material handelt es sich um ein keramisches Material, ein glaskeramisches Material oder um ein Glas.
3. c. Bei dem keramischen Material handelt es sich um Aluminiumoxid (Al₂O₃), um Aluminiumhydroxid (Al(OH)₃), um Aluminiumoxidhydroxid (AIOOH), um Titanoxid (TiO₂), um Titannitrid (TiN), um Titanaluminiumnitrid (TiAIN) oder um Titancarbonitrid (TiCN).

Preferably, the energy storage element according to the invention is further characterized by at least one of the immediately following features a. to c.:

1. a. In the free edge strip of the cathode current collector and/or in the free edge strip of the anode current collector, the surface of the cathode current collector and/or the anode current collector is coated with a supporting material which is more thermally stable than the surface coated therewith.
2. b. The non-metallic material is a ceramic material, a glass-ceramic material or a glass.
3. c. The ceramic material is aluminium oxide (Al ₂ O ₃ ), aluminium hydroxide (Al(OH) ₃ ), aluminium oxide hydroxide (AIOOH), titanium oxide (TiO ₂ ), titanium nitride (TiN), titanium aluminium nitride (TiAIN) or titanium carbonitride (TiCN).

“Thermally more stable” means that the support material remains solid at a temperature at which the surface melts. It therefore has either a higher melting point than the surface or it sublimates or decomposes only at a temperature at which the surface has already melted.

Preferably, both the free edge strip of the cathode current collector and the free edge strip of the anode current collector are coated with the support material. Particularly preferably, the same support material is used in each case.

The contact metal sheets that are in direct contact with the free edge strip(s) are preferably connected to the edge strips by welding. This can lead to problems, namely accidental pressing down or melting of the edge strips of the current collectors. The support material counteracts these problems. It mechanically supports the edge strips of the current collectors and prevents the edges from melting, especially if the edge strips are coated on both sides with the support material. Furthermore, the support material also prevents short circuits that result from the melting of separators of the composite body mentioned at the beginning. The support material electrically insulates the free areas covered by it. In preferred embodiments, it is therefore designed to be electrically insulating.

Further details on suitable support materials are available in the WO 2020/239512 A1 to be taken.

In particularly preferred embodiments, the support material covers not only the edge strip or part of the edge strip of the anode current collector, but also the electrode material arranged on the anode current collector in the main area. The layer of the support material can thus simultaneously also function as a cover layer, which covers, for example, the matrix described above or the nucleation layer described above. This preferably applies when the support material is one of the ceramic materials mentioned.

The support layer can also comprise a binder which, for example, holds ceramic particles of the support layer together.

Preferred embodiments of the composite body

In order to prevent direct contact between oppositely polarized electrodes at the axial ends of a coil or stack, separators are preferably used that are somewhat wider than the electrodes to be separated. In an energy storage element with a wound composite body, the composite body thus ends at its axial ends in preferred embodiments with a separator projection, which accordingly forms the end faces.

In the case of the prismatic configuration described, it is preferred that the edges of the separator(s) form the sides of the stack from which the free edge strips of the current collectors emerge.

It is further preferred that the free edge strips of the current collectors emerging from the terminal end faces of the coil or sides of the stack do not protrude more than 5500 µm, preferably not more than 4000 µm, from the end faces or the sides.

Particularly preferably, the free edge strip of the anode current collector protrudes from the side of the stack or the front side of the coil by no more than 3000 µm, particularly preferably no more than 2000 µm. Particularly preferably, the free edge strip of the cathode current collector protrudes from the side of the stack or the front side of the coil by no more than 4000 µm, particularly preferably no more than 3000 µm.

In the composite body designed as a coil, the strip-shaped anode, the strip-shaped cathode and the strip-shaped separator(s) are preferably wound spirally. To produce the composite body, the strip-shaped electrodes are preferably fed together with the strip-shaped separator(s) to a winding device and are preferably wound spirally around a winding axis in this device. In some embodiments, the electrodes and the separator(s) are wound onto a cylindrical or hollow-cylindrical winding core, which sits on a winding mandrel and remains in the coil after winding.

The winding jacket can be formed, for example, by a plastic film or an adhesive tape. It is also possible for the winding jacket to be formed by one or more separator windings.

Preferred embodiments of the first and/or second contact metal sheet

The contact metal sheet or sheets are preferably connected by welding to the respective current collectors with which they are in direct contact. It is particularly preferably connected directly by welding to the free edge strip of the anode current collector.

In preferred embodiments, the contact metal sheets are made of the same material as the current collectors to which they are connected by welding.

In particularly preferred embodiments, the contact metal sheets, in particular in the case of sodium ion-based energy storage elements according to the invention, consist of aluminum or an aluminum alloy.

The same alloys that were mentioned in connection with current collectors made of an aluminum alloy can be used as aluminum alloy.

In other preferred embodiments, the contact metal sheets consist, for example, of nickel or copper or titanium or a nickel or copper or titanium alloy or of stainless steel.

1. a. Das Kontaktmetallblech weist eine bevorzugt gleichmäßige Dicke im Bereich von 50 µm bis 600 µm, bevorzugt im Bereich von 150 µm bis 350 µm, auf.
2. b. Das Kontaktmetallblech weist zwei sich gegenüberliegenden Flachseiten auf und erstreckt sich im Wesentlichen nur in einer Dimension.
3. c. Das Kontaktmetallblech ist eine Scheibe oder eine bevorzugt rechteckige Platte.
4. d. Das Kontaktmetallblech ist derart dimensioniert, dass es mindestens 60 %, bevorzugt mindestens 70 %, besonders bevorzugt mindestens 80 %, der Seite oder Stirnseite, aus der der mit ihm verbundene freie Randstreifen des jeweiligen Stromkollektors heraustritt, abdeckt.
5. e. Das Kontaktmetallblech weist mindestens eine Durchbrechung, insbesondere mindestens ein Loch und/oder mindestens einen Schlitz, auf.
6. f. Das Kontaktmetallblech weist mindestens eine Sicke auf, die auf einer Flachseite des Kontaktmetallblechs als längliche Vertiefung und auf der gegenüberliegenden Flachseite als längliche Erhöhung zu Tage tritt, wobei das Kontaktmetallblech mit der Flachseite, welche die längliche Erhöhung trägt, auf dem freien Randstreifen des jeweiligen Stromkollektors aufsitzt.
7. g. Das Kontaktmetallblech ist im Bereich der Sicke mit dem freien Randstreifen des Stromkollektors verschweißt, insbesondere über eine oder mehrere in der Sicke angeordnete Schweißnähte und/oder Schweißpunkte.

In a further particularly preferred embodiment of the invention, the first contact metal sheet is characterized by at least one of the immediately following features a. to g.:

1. a. The contact metal sheet preferably has a uniform thickness in the range of 50 µm to 600 µm, preferably in the range of 150 µm to 350 µm.
2. b. The contact metal sheet has two opposing flat sides and extends essentially only in one dimension.
3. c. The contact metal sheet is a disk or a preferably rectangular plate.
4. d. The contact metal sheet is dimensioned such that it covers at least 60%, preferably at least 70%, particularly preferably at least 80%, of the side or front side from which the free edge strip of the respective current collector connected to it protrudes.
5. e. The contact metal sheet has at least one opening, in particular at least one hole and/or at least one slot.
6. f. The contact metal sheet has at least one bead which appears as an elongated depression on one flat side of the contact metal sheet and as an elongated elevation on the opposite flat side, wherein the contact metal sheet sits with the flat side which bears the elongated elevation on the free edge strip of the respective current collector.
7. g. The contact metal sheet is welded to the free edge strip of the current collector in the area of the bead, in particular via one or more weld seams and/or weld points arranged in the bead.

It is particularly preferred that the immediately above features a. and b. and d. are implemented in combination with one another. In a preferred embodiment, the features a. and b. and d. are implemented in combination with one of the features c. or e. or the features f. and g. It is particularly preferred that all features a. to g. are implemented in combination with one another.

Covering the front side as extensively as possible is important for the thermal management of the energy storage element according to the invention. The larger the cover, the more likely it is to be able to contact the first edge of the current collector over its entire length. Heat generated in the composite body can thus be easily dissipated via the contact metal sheet.

It is particularly advantageous if the contact metal sheet is in direct contact with all turns of a winding, including the innermost and outermost turns of the winding.

The at least one opening in the contact metal sheet can be useful, for example, to enable the composite body to be impregnated with an electrolyte.

Electrical connection of the contact metal sheet(s)

• - entweder mit dem Gehäuse elektrisch verbunden oder
• - mit einem Kontaktpol, der durch das Gehäuse geführt und gegenüber dem Gehäuse elektrisch isoliert ist, verbunden, oder
• - das Kontaktmetallblech ist ein Teil des Gehäuses, beispielsweise der Boden eines becherförmig ausgebildeten Gehäuseteils oder der Deckel für ein solches becherförmig ausgebildetes Gehäuseteil.

The contact metal sheet is

• - either electrically connected to the housing or
• - connected to a contact pole which passes through the housing and is electrically insulated from the housing, or
• - the contact metal sheet is a part of the housing, for example the bottom of a cup-shaped housing part or the cover for such a cup-shaped housing part.

The electrical contact to the housing or the contact pole can be realized in particular by welding or a mechanical connection. If necessary, the electrical connection can also be made via a separate electrical conductor.

For optimal connection of the contact metal sheet(s) to the current collectors, it may be preferable to subject the sides or front sides to a mechanical pre-treatment. For example, the current collector edges emerging from the front sides of an electrode coil can be deformed in order to create a suitable receptacle for the elevations of a contact metal sheet with at least one bead, as described above.

Preferred design of the housing parts

Regardless of its shape (e.g. prismatic or cylindrical), the housing of an energy storage element according to the invention is preferably a metal housing. It particularly preferably comprises a cup-shaped housing part and a cover.

1. a. Das becherförmig ausgebildete Gehäuseteil besteht aus Aluminium, einer Aluminiumlegierung, Nickel, Kupfer, Edelstahl oder einem vernickelten Stahl.
2. b. Der Deckel besteht aus Aluminium, einer Aluminiumlegierung, Nickel, Kupfer, Edelstahl oder einem vernickelten Stahl.

In a preferred embodiment of the invention, the energy storage element according to the invention is characterized by at least one of the immediately following features a. and b.:

1. a. The cup-shaped housing part is made of aluminum, an aluminum alloy, nickel, copper, stainless steel or nickel-plated steel.
2. b. The lid is made of aluminum, an aluminum alloy, nickel, copper, stainless steel or nickel-plated steel.

Particularly preferably, the immediately preceding features a. and b. are implemented in combination.

In some embodiments, a direct connection of the free edge strip of one of the current collectors to the housing is desirable. For this purpose, the free edge strip of this current collector can be welded, for example by means of a laser, to the bottom of a cup-shaped housing part. In this case, this bottom serves as a contact plate.

Conversely, in some embodiments it may be provided that a contact plate serves as a cover, i.e. as part of the housing.

Particularly in the case of sodium-ion cells, it can be provided in particularly preferred embodiments that both the cup-shaped housing part and the lid are made of aluminum or an aluminum alloy.

Suitable aluminum alloys for the cup-shaped housing part are, for example, Al alloys of type 1235, 1050, 1060, 1070, 3003, 5052, Mg3, Mg212 (series 3000) and GM55. Also suitable are AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, AlCuTiMg and AlMg. The aluminum content of said alloys is preferably above 99.5%.

In some embodiments, the bottom of the cup-shaped housing part is welded in, i.e. it is manufactured separately and connected to the side wall or walls by welding. In most cases, however, the cup-shaped housing part is manufactured by deep drawing.

Preferred nominal capacity of the energy storage element

The nominal capacity of a sodium ion-based energy storage element according to the invention designed as a cylindrical round cell is preferably up to 10,000 mAh. With a form factor of 21 x 70, the energy storage element in one embodiment as a sodium ion cell preferably has a nominal capacity in the range of 1,000 mAh to 5,000 mAh.

insulation of internal arresters

1. a. Es umfasst ein luft- und flüssigkeitsdicht verschlossenes Gehäuse, das ein metallisches becherförmig ausgebildetes Gehäuseteil mit dem Boden und einer endständigen kreisförmigen Öffnung sowie einen Deckel mit einem kreisförmigen Rand, welche die endständige kreisförmige Öffnung verschließt, aufweist.
2. b. In dem becherförmig ausgebildeten Gehäuseteil ist der Verbundkörper in axialer Ausrichtung angeordnet, wobei die erste Stirnseite in Richtung des Deckels und die zweite Stirnseite in Richtung des Bodens weist, gegebenenfalls unmittelbar mit dem Boden in Kontakt steht.
3. c. Es umfasst eine ringförmige Dichtung aus einem elektrisch isolierenden Material, die den kreisförmigen Rand des Deckels umschließt und das becherförmig ausgebildete Gehäuseteil und den Deckel elektrisch voneinander isoliert.
4. d. Das becherförmig ausgebildete Gehäuseteil umfasst eine Innenseite und eine Außenseite und in axialer Abfolge den Boden, einen Zentralabschnitt und einen Verschlussabschnitt, wobei
   • - der Zentralabschnitt zylindrisch ausgebildet ist und in dem Zentralabschnitt der Wickelmantel des als Wickel ausgebildeten Verbundkörpers mit der Innenseite des becherförmig ausgebildeten Gehäuseteils in Kontakt steht, und
   • - in dem Verschlussabschnitt die ringförmige Dichtung in einem Presskontakt mit dem Deckel und der Innenseite des becherförmig ausgebildeten Gehäuseteils steht.
5. e. Der Zentralabschnitt und der Verschlussabschnitt sind durch eine Einbuchtung, welche die Außenseite des becherförmig ausgebildeten Gehäuseteils ringförmig umläuft, getrennt.
6. f. Das Kontaktmetallblech ist mit dem freien Randstreifen des aus der ersten endständigen Stirnseite austretenden Stromkollektors durch Verschweißung und mit dem Deckel elektrisch, bevorzugt ebenfalls durch Verschweißung, verbunden.
7. g. Das Energiespeicherelement umfasst mindestens ein Isolierelement aus einem elektrisch isolierenden Material, das das Kontaktmetallblech und/oder den ersten Längsrand des aus der ersten endständigen Stirnseite austretenden Stromkollektors und/oder einen an dem Kontaktmetallblech fixierten separaten elektrischen Leiter vor einem unmittelbaren Kontakt mit der Innenseite des becherförmig ausgebildeten Gehäuseteils schützt, insbesondere im Bereich der Einbuchtung.

In particularly preferred embodiments, the energy storage element according to the invention is characterized by the following features a. to g.:

1. a. It comprises an air- and liquid-tight housing which has a metallic cup-shaped housing part with the base and a terminal circular opening and a lid with a circular edge which closes the terminal circular opening.
2. b. In the cup-shaped housing part, the composite body is arranged in an axial orientation, with the first end face pointing towards the lid and the second end face pointing towards the bottom, optionally being in direct contact with the bottom.
3. c. It comprises an annular seal made of an electrically insulating material which encloses the circular edge of the lid and electrically insulates the cup-shaped housing part and the lid from each other.
4. d. The cup-shaped housing part comprises an inner side and an outer side and in axial sequence the base, a central section and a closure section, wherein
   • - the central section is cylindrical and in the central section the winding jacket of the composite body designed as a winding is in contact with the inside of the cup-shaped housing part, and
   • - in the closure section, the annular seal is in press contact with the lid and the inside of the cup-shaped housing part.
5. e. The central section and the closure section are separated by a recess which runs in a ring around the outside of the cup-shaped housing part.
6. f. The contact metal sheet is connected to the free edge strip of the current collector emerging from the first terminal face by welding and is electrically connected to the cover, preferably also by welding.
7. g. The energy storage element comprises at least one insulating element made of an electrically insulating material which protects the contact metal sheet and/or the first longitudinal edge of the current collector emerging from the first terminal end face and/or a separate electrical conductor fixed to the contact metal sheet from direct contact with the inside of the cup-shaped housing part, in particular in the region of the indentation.

This measure ensures that the risk of a short circuit in the cell-internal contact area is reduced. Axial forces that occur, for example, in connection with height calibration, generally no longer lead to direct contact between cell components with opposite polarity. This is prevented by at least one insulating element.

1. a. Das mindestens eine Isolierelement ist oder umfasst ein Isolierband, das auf die Kante, welche die Stirnseite begrenzt, aufgebracht ist und diese vor einem unmittelbaren Kontakt mit der Innenseite schützt.
2. b. Das mindestens eine Isolierelement ist oder umfasst ringförmiges Formteil aus Kunststoff mit bevorzugt L-förmigem Querschnitt, das auf die Kante, welche die Stirnseite begrenzt, aufgebracht ist und diese vor einem unmittelbaren Kontakt mit der Innenseite schützt.
3. c. Das Isolierband oder das ringförmige Formteil aus Kunststoff weist eine Dicke im Bereich von 10 µm bis 200 µm auf.

In a first preferred development of this preferred embodiment, the energy storage element according to the invention is characterized by at least one of the immediately following features a. to c.:

1. a. The at least one insulating element is or comprises an insulating tape which is applied to the edge which delimits the front side and protects it from direct contact with the inner side.
2. b. The at least one insulating element is or comprises an annular molded part made of plastic with a preferably L-shaped cross-section, which is applied to the edge which delimits the front side and protects it from direct contact with the inner side.
3. c. The insulating tape or the ring-shaped plastic molded part has a thickness in the range of 10 µm to 200 µm.

It is preferred that the immediately preceding features a. and c. as well as b. and c. are realized in combination.

The insulating tape can, for example, be a Kapton/polyimide adhesive tape.

The ring-shaped plastic part, preferably with an L-shaped cross-section, can be manufactured by injection molding, for example, and pushed onto the edge to be protected. It can be made of Teflon or polyamide, for example.

1. a. Das mindestens eine Isolierelement ist oder umfasst ein ringförmiges Isolierelement aus Kunststoff, das an der Innenseite des becherförmig ausgebildeten Gehäuseteils im Bereich der Einbuchtung anliegt und diese vor einem unmittelbaren Kontakt mit dem Kontaktmetallblech schützt.
2. b. Das ringförmige Isolierelement ist ein Teilabschnitt der ringförmigen Dichtung.
3. c. Das ringförmige Isolierelement aus Kunststoff weist eine Dicke im Bereich von 20 µm bis 400 µm auf.

In a second preferred development of this preferred embodiment, the energy storage element according to the invention is characterized by at least one of the immediately following features a. to c.:

1. a. The at least one insulating element is or comprises an annular insulating element made of plastic, which rests on the inside of the cup-shaped housing part in the region of the indentation and protects it from direct contact with the contact metal sheet.
2. b. The annular insulating element is a partial section of the annular seal.
3. c. The ring-shaped plastic insulating element has a thickness in the range of 20 µm to 400 µm.

It is preferred that the immediately above features a. and b. are implemented in combination. Particularly preferably, features a. to c. are implemented in combination.

The ring-shaped insulating element can also be an injection-molded part, as can the ring-shaped seal. The thickness of the insulating element is preferably in a range from 20 µm to 400 µm.

The ring-shaped insulating element can, for example, consist of Teflon, polyamide, polybutylene terephthalate or a perfluoroalkoxy polymer.

1. a. Das mindestens eine Isolierelement ist oder umfasst ein ringförmiges Kunststoffteil, das das Kontaktmetallblech umschließt und dieses vor einem unmittelbaren Kontakt mit der Innenseite des becherförmig ausgebildeten Gehäuseteils im Bereich der Einbuchtung schützt.
2. b. Das ringförmige Kunststoffteil ist hohlzylindrisch ausgebildet, umfasst einen Mantel und wird stirnseitig durch je einen umlaufenden Rand begrenzt.
3. c. Das ringförmige Kunststoffteil ist hohlzylindrisch ausgebildet, umfasst einen Mantel und wird stirnseitig durch je einen umlaufenden Rand begrenzt, wobei einer der Ränder auf als nach außen gerichteter ringförmiger Kragen ausgebildet ist und auf dem Kontaktmetallblech aufsitzt.
4. d. Das ringförmige Kunststoffteil weist eine Dicke im Bereich von 20 µm bis 600 µm auf.

In a third preferred development of this preferred embodiment, the energy storage element according to the invention is characterized by at least one of the immediately following features a. to d.:

1. a. The at least one insulating element is or comprises an annular plastic part which encloses the contact metal sheet and protects it from direct contact with the inside of the cup-shaped housing part in the region of the indentation.
2. b. The ring-shaped plastic part is hollow-cylindrical, comprises a casing and is limited on each end by a circumferential edge.
3. c. The ring-shaped plastic part is hollow-cylindrical, comprises a casing and is delimited at the front by a circumferential edge, whereby one of the edges is designed as an outward-facing ring-shaped collar and sits on the contact metal sheet.
4. d. The ring-shaped plastic part has a thickness in the range of 20 µm to 600 µm.

It is preferred that the immediately preceding features a. and b., particularly preferably the features a. and b. and d., are implemented in combination. Particularly preferably the immediately preceding features a. and c. and d. are implemented in combination.

The ring-shaped plastic part can also be an injection-molded part. The thickness of the plastic part is preferably in a range of 20 µm to 600 µm.

The plastic part can, for example, be made of Teflon, polyamide, polybutylene terephthalate or a perfluoroalkoxy polymer.

1. a. Das mindestens eine Isolierelement ist oder umfasst eine elektrisch isolierende Kunststoffbeschichtung, die einen Rand des Kontaktmetallblechs umschließt und diesen vor einem unmittelbaren Kontakt mit der Innenseite des becherförmig ausgebildeten Gehäuseteils, insbesondere im Bereich der Einbuchtung, schützt.
2. b. Die elektrisch isolierende Beschichtung ist durch Umspritzen des Randes des Kontaktmetallblechs gebildet.

In a fourth preferred development of this preferred embodiment, the energy storage element according to the invention is characterized by at least one of the immediately following features a. to d.:

1. a. The at least one insulating element is or comprises an electrically insulating plastic coating which encloses an edge of the contact metal sheet and protects it from direct contact with the inside of the cup-shaped housing part, in particular in the region of the indentation.
2. b. The electrically insulating coating is formed by overmolding the edge of the contact metal sheet.

It is preferred that the immediately preceding features a. and b. are realized in combination.

Basically, all thermoplastics with electrically insulating properties are suitable for overmolding the edge of the contact metal sheet. Polyamide, for example, is suitable.

1. a. Das mindestens eine Isolierelement umfasst ein Isolierband oder ringförmiges Formteil aus Kunststoff, das auf die Kante, welche die Stirnseite begrenzt, aufgebracht ist und diese vor einem unmittelbaren Kontakt mit der Innenseite schützt, also ein Isolierband oder ein ringförmiges Formteil gemäß der ersten besonders bevorzugten Ausführungsform, und/oder
2. b. das mindestens eine Isolierelement umfasst ein ringförmiges Isolierelement, das an der Innenseite des becherförmig ausgebildeten Gehäuseteils im Bereich der Einbuchtung anliegt und diese vor einem unmittelbaren Kontakt mit dem Kontaktmetallblech schützt, also ein ringförmiges Isolierelement gemäß der zweiten besonders bevorzugten Ausführungsform, und/oder
3. c. das mindestens eine Isolierelement umfasst ein ringförmiges Kunststoffteil, das das Kontaktmetallblech umschließt und dieses vor einem unmittelbaren Kontakt mit der Innenseite des becherförmig ausgebildeten Gehäuseteils im Bereich der Einbuchtung schützt, also ein ringförmiges Kunststoffteil gemäß der dritten besonders bevorzugten Ausführungsform, und/oder
4. d. das mindestens eine Isolierelement ist oder umfasst eine elektrisch isolierende Kunststoffbeschichtung, die einen Rand des Kontaktmetallblechs umschließt und diesen vor einem unmittelbaren Kontakt mit der Innenseite des becherförmig ausgebildeten Gehäuseteils, insbesondere im Bereich der Einbuchtung, schützt, also eine Kunststoffbeschichtung gemäß der vierten besonders bevorzugten Ausführungsform.

Combinations of the four particularly preferred embodiments described are also in accordance with the invention. The energy storage element is particularly preferably characterized by a combination of two or more of the four immediately following features a. to d.:

1. a. The at least one insulating element comprises an insulating tape or annular molded part made of plastic, which is applied to the edge which delimits the front side and protects it from direct contact with the inner side, i.e. an insulating tape or annular molded part according to the first particularly preferred embodiment, and/or
2. b. the at least one insulating element comprises an annular insulating element which rests on the inside of the cup-shaped housing part in the region of the indentation and protects it from direct contact with the contact metal sheet, i.e. an annular insulating element according to the second particularly preferred embodiment, and/or
3. c. the at least one insulating element comprises an annular plastic part which encloses the contact metal sheet and protects it from direct contact with the inside of the cup-shaped housing part in the region of the indentation, i.e. an annular plastic part according to the third particularly preferred embodiment, and/or
4. d. the at least one insulating element is or comprises an electrically insulating plastic coating which encloses an edge of the contact metal sheet and protects it from direct contact with the inside of the cup-shaped housing part, in particular in the region of the indentation, i.e. a plastic coating according to the fourth particularly preferred embodiment.

1. a. Das becherförmig ausgebildete Gehäuseteil weist in dem Zentralabschnitt und dem Verschlussabschnitt einen identischen maximalen Außendurchmesser auf.
2. b. Im Bereich der Einbuchtung ist der Außendurchmesser des becherförmig ausgebildeten Gehäuseteils um das 4- bis 20-fache der Wandstärke des becherförmig ausgebildeten Gehäuseteils in diesem Bereich reduziert.

It is preferred that the energy storage element according to the invention is characterized by at least one of the following features a. to c.:

1. a. The cup-shaped housing part has an identical maximum outer diameter in the central section and the closure section.
2. b. In the area of the indentation, the outer diameter of the cup-shaped housing part is reduced by 4 to 20 times the wall thickness of the cup-shaped housing part in this area.

It is preferred that the immediately preceding features a. and b. are realized in combination.

cell closure by potting compound

1. a. Es umfasst ein luft- und flüssigkeitsdicht verschlossenes Gehäuse, das ein metallisches, becherförmig ausgebildetes Gehäuseteil mit einem Boden und einer endständigen Öffnung sowie einen Deckel, welche die endständige Öffnung verschließt, aufweist.
2. b. Der Deckel umfasst eine metallische Deckelplatte und einen Anschlusspol, der durch eine Durchbrechung in der Deckelplatte geführt und gegenüber der Deckelplatte elektrisch isoliert ist,
3. c. In dem becherförmig ausgebildeten Gehäuseteil ist der Verbundkörper angeordnet, wobei dieser mit einer Seite in Richtung des Deckels und mit einer zweiten Seite in Richtung des Bodens weist, gegebenenfalls unmittelbar mit dem Boden in Kontakt steht.
4. d. Der die Kathode und die Anode sind derart ausgebildet und/oder innerhalb des Verbundkörpers derart zueinander angeordnet, dass der freie Randstreifen des Kathodenstromkollektors aus der Seite des Verbundkörpers und der freie Randstreifen des Anodenstromkollektors aus einer Seite des Verbundkörpers austritt, und
5. e. Das Kontaktmetallblech sitzt unmittelbar auf dem freien Randstreifen eines der aus einer der Seiten des Verbundkörpers austretenden Stromkollektoren auf und ist mit diesem durch Verschweißung verbunden.
6. f. Das Kontaktmetallblech ist entweder mit dem durch die Durchbrechung in der Deckelplatte geführten Anschlusspol elektrisch verbunden, vorzugsweise unmittelbar mit dem Anschlusspol unmittelbar verschweißt, oder der Anschlusspol ist ein Teil des Kontaktmetallblechs.
7. g. Der Anschlusspol ist durch eine ausgehärtete Vergussmasse aus einem elektrisch isolierenden Kunststoffmaterial von der Deckelplatte elektrisch isoliert.

In a particularly preferred embodiment, the energy storage element according to the invention is characterized by the following features a. to g.:

1. a. It comprises an air- and liquid-tight housing which has a metallic, cup-shaped housing part with a base and an end opening as well as a lid which closes the end opening.
2. b. The cover comprises a metallic cover plate and a connection pole which is guided through an opening in the cover plate and is electrically insulated from the cover plate,
3. c. The composite body is arranged in the cup-shaped housing part, with one side pointing towards the lid and a second side pointing towards the bottom, possibly being in direct contact with the bottom.
4. d. The cathode and the anode are designed and/or arranged relative to one another within the composite body in such a way that the free edge strip of the cathode current collector emerges from the side of the composite body and the free edge strip of the anode current collector emerges from one side of the composite body, and
5. e. The contact metal sheet sits directly on the free edge strip of one of the current collectors emerging from one of the sides of the composite body and is connected to it by welding.
6. f. The contact metal sheet is either electrically connected to the connection pole passing through the opening in the cover plate, preferably directly welded to the connection pole, or the connection pole is part of the contact metal sheet.
7. g. The connection pole is electrically insulated from the cover plate by a hardened potting compound made of an electrically insulating plastic material.

A cover of this design ensures that there is essentially no dead volume between the composite body and the metal cover plate. Any space between the contact metal sheet, the connection pole and the cover plate can be filled with the potting compound. A cover with the features mentioned can be built very compactly.

Furthermore, an energy storage element with the immediately above features a. to g. has the advantage that it is possible to electrically contact both the anode and the cathode via the cover.

1. a. Der nicht mit dem Kontaktmetallblech in unmittelbarem Kontakt stehende Randstreifen des Kathodenstromkollektors oder des Anodenstromkollektors ist elektrisch mit dem Gehäuseboden verbunden, bevorzugt unmittelbar an den Gehäuseboden geschweißt.

In a preferred development of this embodiment, the energy storage element according to the invention is characterized by the immediately following feature a.:

1. a. The edge strip of the cathode current collector or the anode current collector which is not in direct contact with the contact metal sheet is electrically connected to the housing base, preferably welded directly to the housing base.

1. a. Das becherförmig ausgebildete Gehäuseteil ist elektrisch mit der Kathode verbunden.
2. b. Das becherförmig ausgebildete Gehäuseteil besteht aus Aluminium oder einer Aluminiumlegierung.
3. c. Die Deckelplatte besteht aus Aluminium oder einer Aluminiumlegierung.

In many cases, it is preferred in this embodiment that the cup-shaped housing part is positively polarized and the connection pole is a negative connection pole. In these cases, the energy storage element according to the invention is characterized by the immediately following feature a., optionally in combination with at least one further of the immediately following features b. and c.:

1. a. The cup-shaped housing part is electrically connected to the cathode.
2. b. The cup-shaped housing part is made of aluminum or an aluminum alloy.
3. c. The cover plate is made of aluminum or an aluminum alloy.

Particularly preferably, the immediately preceding features a. to c. are implemented in combination.

In this embodiment, the housing of the energy storage element consists essentially of aluminum or an aluminum alloy. This has various advantages. The formation of local elements when the outside of the cell comes into contact with moisture is excluded. The housing itself can basically serve as a positive connection pole on all of its sides. However, it is particularly preferred that the cell is contacted exclusively via the cover, where the negative connection pole is also located. For this purpose, a current conductor can be welded directly to the cover plate or alternatively fixed to the separate connection pole, for example by welding.

1. a. Das becherförmig ausgebildete Gehäuseteil ist elektrisch mit der Anode verbunden.
2. b. Das becherförmig ausgebildete Gehäuseteil besteht aus Aluminium oder einer Aluminiumlegierung.
3. c. Die Deckelplatte besteht aus Aluminium oder einer Aluminiumlegierung.

In other cases, it may be preferred that the cup-shaped housing part is negatively polarized and the connection pole is a positive connection pole. In these cases, the energy storage element according to the invention is characterized by the immediately following feature a., optionally in combination with at least one further of the immediately following features b. and c.:

1. a. The cup-shaped housing part is electrically connected to the anode.
2. b. The cup-shaped housing part is made of aluminum or an aluminum alloy.
3. c. The cover plate is made of aluminum or an aluminum alloy.

Particularly preferably, the immediately preceding features a. to c. are implemented in combination.

1. a. Zwischen der Deckelplatte und dem Kontaktmetallblech befindet sich ein ringförmiger Spalt, der mit der Vergussmasse befüllt ist.
2. b. Der ringförmige Spalt wird radial nach außen durch eine O-Ring-förmige Isolierscheibe aus einem elektrisch isolierenden Kunststoffmaterial begrenzt.

In preferred embodiments, the energy storage element according to the invention is characterized by at least one of the following features a. and b.:

1. a. Between the cover plate and the contact metal sheet there is an annular gap which is filled with the potting compound.
2. b. The annular gap is limited radially outwards by an O-ring-shaped insulating disc made of an electrically insulating plastic material.

1. a. Das Kontaktmetallblech besteht aus Aluminium oder aus einer Aluminiumlegierung.
2. b. Der Anschlusspol besteht aus Aluminium oder einer Aluminiumlegierung.
3. c. Das Kontaktmetallblech und der Anschlusspol und Kathodenstromkollektor bestehen aus dem gleichen Material.

In further particularly preferred embodiments, the energy storage element according to the invention is characterized by at least one of the immediately following features a. to c.:

1. a. The contact metal sheet is made of aluminum or an aluminum alloy.
2. b. The connecting pole is made of aluminum or an aluminum alloy.
3. c. The contact metal sheet and the terminal pole and cathode current collector are made of the same material.

In embodiments in which the connection pole is part of the contact metal sheet, the contact metal sheet serves simultaneously as a conductor for the current from the anode or cathode current collector and as a pole. Accordingly, no separate electrical conductor is required, as is known from the prior art, and there usually between a cover or a cover assembly and a contact plate, as in the WO 2017/215900 A1 described.

In this embodiment, the contact metal sheet preferably comprises a flat region which sits directly on the free edge strip of one of the current collectors emerging from one of the sides of the composite body and is connected to it by welding, and a projection pointing away from this side. The projection serves as the connection pole and is preferably guided through the opening in the cover plate.

1. a. Der von der ersten endständigen Stirnseite weg weisende Vorsprung des Metallteils ist napfförmig ausgebildet.
2. b. Das Kontaktmetallblech einschließlich des Vorsprungs ist einstückig ausgebildet.

Preferably, the contact metal sheet is characterized by at least one of the following features a. and b.:

1. a. The projection of the metal part pointing away from the first terminal face is cup-shaped.
2. b. The contact metal sheet including the projection is formed in one piece.

It is preferred that the immediately preceding features a. and b. are realized in combination.

The contact metal sheet with the cup-shaped projection can be produced, for example, in a deep-drawing process, and is then preferably formed in one piece. However, it can also be manufactured, for example, by a forming or machining production step from a metallic workpiece or by means of 3D printing.

1. a. der Gehäuseboden des becherförmig ausgebildeten Gehäuseteils weist eine Primärsicherung gegen internen Überdruck in Form einer Durchbrechung, die mittels einer metallischen Membran verschlossen ist, auf.
2. b. der Gehäuseboden des becherförmig ausgebildeten Gehäuseteils weist eine Sekundärsicherung gegen internen Überdruck in Form mindestens einer Nut auf seiner Innenseite oder seiner Außenseite auf.

In a particularly preferred embodiment of the invention, the energy storage element according to the invention is characterized by the following features a. and b.:

1. a. the housing base of the cup-shaped housing part has a primary protection against internal overpressure in the form of an opening which is closed by means of a metallic membrane.
2. b. the housing base of the cup-shaped housing part has a secondary protection against internal overpressure in the form of at least one groove on its inside or outside.

The primary safety device has the function of bringing about a controlled pressure equalization when an inadmissible overpressure above a defined threshold occurs. In this case, the membrane is If the case is burst open or blown off by pressure, gas formed inside the case can escape through the hole in the case bottom.

The secondary fuse is intended for cases where pressure equalization via the primary fuse does not occur quickly enough. In this case, the housing base can rupture due to the excess pressure along the groove, which represents nothing more than a weakening of the structure of the housing base, so that an outlet opening with a comparatively large cross-section is created through which gas formed inside the housing can escape.

Such safety solutions are already known. By appropriately designing the groove and the membrane, the pressure at which the safety devices are triggered can be precisely adjusted.

Since the safety functions mentioned are not integrated into the lid - as is the case with many classic cells - but instead into the housing base, it is possible to build the lid extremely compactly. Pre-assembly of the lid is also not absolutely necessary. The lid can instead be manufactured during housing assembly.

1. a. Die Deckelplatte ist in die endständige Öffnung des becherförmig ausgebildeten Gehäuseteils eingeschweißt.
2. b. Das Kontaktmetallblech ist mit dem Kontaktmetallblech des Anodenstromkollektors oder dem freien Randstreifen des Kathodenstromkollektors durch Verschweißung verbunden.
3. c. Der nicht mit dem Kontaktmetallblech in unmittelbarem Kontakt stehende freie Randstreifen sitzt unmittelbar auf dem Gehäuseboden auf.
4. d. Der nicht mit dem Kontaktmetallblech in unmittelbarem Kontakt stehende freie Randstreifen ist durch Verschweißung mit dem Gehäuseboden verbunden.
5. e. Die mindestens eine Nut findet sich auf der Innenseite des Gehäusebodens.

In particularly preferred embodiments, the energy storage element according to the invention is characterized by at least one of the following features a. to e.:

1. a. The cover plate is welded into the terminal opening of the cup-shaped housing part.
2. b. The contact metal sheet is connected to the contact metal sheet of the anode current collector or the free edge strip of the cathode current collector by welding.
3. c. The free edge strip not in direct contact with the contact metal sheet sits directly on the housing base.
4. d. The free edge strip not in direct contact with the contact metal sheet is connected to the housing base by welding.
5. e. At least one groove is located on the inside of the housing base.

Preferably, the immediately preceding features a. to d. are implemented in combination, particularly preferably the immediately preceding features a. to e.

1. a. Die metallische Membran ist durch Verschweißung am Boden des becherförmig ausgebildeten Gehäuseteils fixiert.

In a further particularly preferred embodiment of the invention, the energy storage element according to the invention is characterized by the following feature a.:

1. a. The metallic membrane is fixed by welding to the bottom of the cup-shaped housing part.

The base of the cup-shaped housing part can have a shallow recess into which the membrane is placed so that it does not add bulk. It is preferably connected to the base via a circular weld seam that runs around the opening in the base.

The thickness of the membrane can be adjusted to the pressure at which the fuse should trigger.

1. a. Der Gehäuseboden weist mindestens eine Sicke auf, die auf seiner Außenseite als längliche Vertiefung und auf seiner Innenseite als längliche Erhöhung zu Tage tritt, wobei der nicht mit dem Kontaktmetallblech in unmittelbarem Kontakt stehende Randstreifen des Kathodenstromkollektors oder des Anodenstromkollektors auf der Innenseite aufsitzt.
2. b. Der nicht mit dem Kontaktmetallblech in unmittelbarem Kontakt stehende Randstreifen des Kathodenstromkollektors oder des Anodenstromkollektors ist elektrisch mit dem Gehäuseboden verbunden, bevorzugt unmittelbar an den Gehäuseboden geschweißt.
3. c. Der Gehäuseboden ist im Bereich der Sicke mit dem freien Randstreifen des Anodenstromkollektors oder dem freien Randstreifen des Kathodenstromkollektors verschweißt.
4. d. Die Durchbrechung ist im Zentrum des Gehäusebodens positioniert.
5. e. Die mindestens eine Sicke umfasst mehrere lineare Sicken, insbesondere drei Sicken, die in sternförmiger Anordnung um die Durchbrechung herum angeordnet sind.
6. f. Die mindestens eine Sicke umfasst mehrere lineare Teilabschnitte, die in sternförmiger Anordnung um die Durchbrechung herum angeordnet sind.
7. g. Die mindestens eine Sicke umfasst einen um die Durchbrechung herumlaufenden Teilabschnitt, der die sternförmig angeordneten linearen Teilabschnitte miteinander verbindet.

In preferred embodiments, the energy storage element according to the invention is characterized by at least one of the following features a. to g.:

1. a. The housing base has at least one bead which appears on its outer side as an elongated depression and on its inner side as an elongated elevation, with the edge strip of the cathode current collector or the anode current collector which is not in direct contact with the contact metal sheet resting on the inner side.
2. b. The edge strip of the cathode current collector or the anode current collector which is not in direct contact with the contact metal sheet is electrically connected to the housing base, preferably welded directly to the housing base.
3. c. The housing base is welded in the area of the bead to the free edge strip of the anode current collector or the free edge strip of the cathode current collector.
4. d. The opening is positioned in the center of the case back.
5. e. The at least one bead comprises a plurality of linear beads, in particular three beads, which are arranged in a star-shaped arrangement around the opening.
6. f. The at least one bead comprises a plurality of linear sections arranged in a star-shaped arrangement around the opening.
7. g. The at least one bead comprises a section running around the opening, which connects the star-shaped linear sections to one another.

Preferably, the immediately preceding features a. and b., c. and d. as well as c. and e. and f. are implemented in combination. Particularly preferably, the immediately preceding features a. to g. are implemented in combination.

As a result of the welding in the area of the bead, one or more weld seams are preferably found in this area. The star-shaped beads and the star-shaped linear sections of the groove preferably each enclose an angle of 120°.

In some embodiments, it has proven advantageous to subject the free edge strip of the current collector, which sits on the inside of the housing base, to a pretreatment so that the contact between the housing base and the current collector is improved. In particular, at least one recess can be folded into the edge, which corresponds to the at least one bead.

The edge of the current collector can also have been subjected to a directional deformation through pretreatment. For example, it can be bent in a defined direction.

Battery according to the invention

Energy storage elements of the type according to the invention, in particular based on sodium ion technology, not only offer high power densities, they are also capable of rapid charging, perform well at low temperatures and offer excellent cycle stability. In addition, sodium, for example, is available in practically unlimited quantities.

For all these reasons, energy storage elements according to the invention, in particular those based on sodium ion technology, are excellently suited for use in starter batteries, which can serve as a replacement for lead accumulators, for example in motor vehicles.

• - jede Batterie, die zwei oder mehr in Serie und/oder parallel miteinander verschaltete erfindungsgemäße Energiespeicherelement, insbesondere solche auf Basis von Natrium-lonen-Technologie, aufweist.

The invention described here comprises accordingly

• - any battery which has two or more energy storage elements according to the invention connected in series and/or parallel, in particular those based on sodium ion technology.

Particularly preferably, the battery according to the invention comprises a plurality of energy storage elements according to the invention, which are interconnected in such a way that the battery supplies a voltage of 12 volts or 24 volts.

Typically, an energy storage element according to the invention based on sodium ion technology delivers a nominal voltage in the range from 1.5 volts to 4.8 volts, preferably from 2.4 volts to 4 volts. Accordingly, a battery according to the invention with a nominal voltage of 12 V preferably comprises 3 to 5 energy storage elements according to the invention connected in series.

Further features and advantages of the invention emerge from the claims and from the following description of preferred embodiments of the invention in conjunction with the drawings. The individual features can be implemented individually or in combination with one another.

Short description of the drawings

• - 1 eine erste Ausführungsform eines erfindungsgemäßen Energiespeicherelements des Natrium-Ionen-Typs (Querschnittsdarstellung),
• - 2 eine zweite Ausführungsform einer erfindungsgemäßen Energiespeicherelements des Natrium-lonen-Typs,
• - 3 eine dritte Ausführungsform eines erfindungsgemäßen Energiespeicherelements des Natrium-Ionen-Typs (Querschnittsdarstellung),
• - 4 mehrere Ausführungsformen eines Kontaktmetallblechs, das sich zur Kontaktierung des ersten Längsrands des aus der ersten endständigen Stirnseite austretenden Stromkollektors eines erfindungsgemäßen Energiespeicherelements des Natrium-Ionen-Typs eignet (perspektivische Darstellung),
• - 5 einen Verbundkörper, der Bestandteil eines erfindungsgemäßen Energiespeicherelements des Natrium-Ionen-Typs ist, sowie dessen Komponenten (Draufsicht bzw. perspektivische Darstellung),
• - 6 weitere Ausführungsformen des Kontaktmetallblechs, das sich zur Kontaktierung des ersten Längsrands des aus der ersten endständigen Stirnseite austretenden Stromkollektors eines erfindungsgemäßen Energiespeicherelements des Natrium-Ionen-Typs eignet (perspektivische Darstellung),
• - 7 Darstellungen einer Ausführungsform eines erfindungsgemäßen Energiespeicherelements von außen und in einem Längsschnitt,
• - 8 Detaildarstellungen des oberen und des unteren stirnseitigen Bereichs einer Ausführungsform eines erfindungsgemäßen Energiespeicherelements in einem Längsschnitt,
• - 9A, B Detaildarstellungen eines Anschlusspols für eine bevorzugte Ausführungsform eines erfindungsgemäßen Energiespeicherelements in einer Ansicht schräg von oben und in einer Schnittansicht,
• - 10A, B Detaildarstellungen einer Isolierscheibe für eine bevorzugte Ausführungsform eines erfindungsgemäßen Energiespeicherelements gemäß einer der 7 bis 9 in einer Ansicht schräg von oben und in einer Schnittansicht,
• - 11A, B Detaildarstellungen eines Kontaktmetallblechs für die in 7 dargestellte bevorzugte Ausführungsform eines erfindungsgemäßen Energiespeicherelements in einer Ansicht schräg von oben und in einer Schnittansicht schräg von unten,
• - 12 Detaildarstellung des Gehäusebodens einer bevorzugten Ausführungsform eines erfindungsgemäßen Energiespeicherelements gemäß 7,
• - 13A-C Darstellungen der verschiedenen Komponenten einer bevorzugten Ausführungsform eines erfindungsgemäßen Energiespeicherelements gemäß 7 in Explosionsansichten,
• - 14A,B Detaildarstellungen aus dem oberen stirnseitigen Bereich einer bevorzugten Ausführungsform eines erfindungsgemäßen Energiespeicherelements gemäß zur IIlustrierung eines möglichen Verfahrens zur Herstellung des Energiespeicherelements,
• - 15 Darstellung einer bevorzugten Ausführungsform eines erfindungsgemäßen Energiespeicherelements schräg von oben auf den Gehäuseboden zur Illustrierung eines Verfahrens zur Herstellung des Energiespeicherelements,
• - 16A,B Alternative Ausführungsform eines Kontaktmetallblechs mit daran angefügtem Anschlusspol und deren Einbau in eine bevorzugte Ausführungsform eines erfindungsgemäßen Energiespeicherelements in Schnittansichten, und
• - 17 Beispiel einer Deckelbaugruppe, die beispielsweise als Deckel bei einem erfindungsgemäßen Energiespeicherelement gemäß 1 oder 2 oder 3 verbaut werden kann.

The drawings show schematically

• - 1 a first embodiment of an energy storage element of the sodium ion type according to the invention (cross-sectional view),
• - 2 a second embodiment of an energy storage element of the sodium ion type according to the invention,
• - 3 a third embodiment of an energy storage element of the sodium ion type according to the invention (cross-sectional view),
• - 4 several embodiments of a contact metal sheet which is suitable for contacting the first longitudinal edge of the current collector emerging from the first terminal end face of an energy storage element of the sodium ion type according to the invention (perspective representation),
• - 5 a composite body which is part of an energy storage element of the sodium ion type according to the invention, as well as its components (top view or perspective view),
• - 6 further embodiments of the contact metal sheet which is suitable for contacting the first longitudinal edge of the current collector emerging from the first terminal end face of an energy storage element of the sodium ion type according to the invention (perspective representation),
• - 7 Representations of an embodiment of an energy storage element according to the invention from the outside and in a longitudinal section,
• - 8 Detailed representations of the upper and lower frontal area of an embodiment of an energy storage element according to the invention in a longitudinal section,
• - 9A , B Detailed representations of a connection pole for a preferred embodiment of an energy storage element according to the invention in a view obliquely from above and in a sectional view,
• - 10A , B Detailed representations of an insulating disk for a preferred embodiment of an energy storage element according to the invention according to one of the 7 to 9 in a view obliquely from above and in a sectional view,
• - 11A , B Detailed representations of a contact metal sheet for the 7 illustrated preferred embodiment of an energy storage element according to the invention in a view obliquely from above and in a sectional view obliquely from below,
• - 12 Detailed view of the housing base of a preferred embodiment of an energy storage element according to the invention according to 7 ,
• - 13A-C Representations of the various components of a preferred embodiment of an energy storage element according to the invention according to 7 in exploded views,
• - 14A ,B Detailed representations from the upper front area of a preferred embodiment of an energy storage element according to the invention according to the illustration of a possible method for producing the energy storage element,
• - 15 Representation of a preferred embodiment of an energy storage element according to the invention obliquely from above onto the housing base to illustrate a method for producing the energy storage element,
• - 16A ,B Alternative embodiment of a contact metal sheet with a connecting pole attached thereto and its installation in a preferred embodiment of an energy storage element according to the invention in sectional views, and
• - 17 Example of a cover assembly which, for example, serves as a cover in an energy storage element according to the invention according to 1 or 2 or 3 can be installed.

Detailed description of the embodiments

1 shows an energy storage element 100 according to the invention with an air- and liquid-tight housing, which comprises a metallic, cup-shaped housing part 101 with a circular opening at the end and a cover 102 with a circular edge 102a, which closes the circular opening. The energy storage element further comprises an annular seal 103 made of an electrically insulating material, which encloses the circular edge 102a of the cover 102 and electrically insulates the cup-shaped housing part 101 and the cover 102 from one another.

The lid is shown in the form of a disc. However, multi-part lid assemblies are regularly used as lids, for example the ones in 17 depicted.

The cup-shaped housing part 101 comprises, in axial sequence, a base 101a, a central section 101b and a closure section 101c, wherein the central section 101b is cylindrical and in the central section 101b the winding jacket 104c of the composite body 104 designed as a winding is in contact with the inner side 101d of the cup-shaped housing part 101, and in the closure section 101c the annular seal 103 is in press contact with the cover 102 and the inner side of the cup-shaped housing part 101. The central section 101b and the closure section 101c are separated by an indentation 111 which runs annularly around the outer side 101e of the cup-shaped housing part 101.

The composite body 104 in the form of a cylindrical winding with the sequence anode/separator/cathode is not shown in detail here. Only the longitudinal edge 106a of the anode current collector 106, which emerges from the front side 104a of the composite body 104, and the longitudinal edge 109a of the cathode current collector 109, which emerges from the front side 104b of the composite body 104, can be seen. The longitudinal edge 109a is welded directly to the housing base 101a, preferably over its entire length. The longitudinal edge 106a is welded directly to the contact metal sheet 112, preferably over its entire length. The contact metal sheet 112 is in turn connected to the cover 102 via the electrical conductor 133.

The energy storage element 100 preferably has a height in the range of 60 mm to 100 mm, and its diameter is preferably in the range of 20 mm to 50 mm. The cup-shaped housing part 101 typically has a wall thickness in the range of 0.1 mm to 0.3 mm in the central section 101b.

The energy storage element comprises an electrically insulating plastic coating 180 as an insulating element, which surrounds the edge of the contact metal sheet 112 and protects it from direct contact with the inner side 101d of the cup-shaped housing part 101, in particular in the area of the indentation 111. The electrically insulating coating 180 is formed by overmolding the edge of the contact metal sheet 112. The energy storage element 100 also comprises an annular plastic part 170 as an insulating element, which surrounds the separate electrical conductor 133 fixed to the contact metal sheet and protects it from direct contact with the inner side 101d of the cup-shaped housing part 101 in the area of the indentation 111.

As a result, the energy storage element 100 is excellently protected against short circuits even in the event of deformation of the housing as a result of an external mechanical force.

2 shows an energy storage element 100 according to the invention with an air- and liquid-tight housing, which comprises a metallic, cup-shaped housing part 101 with a circular opening at the end and a cover 102 with a circular edge 102a, which closes the circular opening. The energy storage element further comprises an annular seal 103 made of an electrically insulating material, which encloses the circular edge 102a of the cover 102 and electrically insulates the cup-shaped housing part 101 and the cover 102 from one another.

The lid is shown in the form of a disc. However, multi-part lid assemblies are regularly used as lids, for example the ones in 17 depicted.

The cup-shaped housing part 101 comprises, in axial sequence, a base 101a, a central section 101b and a closure section 101c, wherein the central section 101b is cylindrical and in the central section 101b the winding jacket 104c of the composite body 104 designed as a winding is in contact with the inner side 101d of the cup-shaped housing part 101 (Attention: For reasons of clarity only, the composite body 104 is shown spaced apart from the inner side 101d, but in fact it presses against it, as is the case, for example, in 1 shown), and in the closure section 101c the annular seal 103 is in press contact with the cover 102 and the inside of the cup-shaped housing part 101. The central section 101b and the closure section 101c are separated by an indentation 111 which runs annularly around the outside 101e of the cup-shaped housing part 101.

The composite body 104 in the form of a cylindrical coil with the sequence anode / separator / cathode is not shown in detail here. Only the longitudinal edge 106a of the anode current collector 106, which emerges from the front side 104a of the composite body 104, and the longitudinal edge 109a of the Cathode current collector 109, which emerges from the front side 104b of the composite body 104. The longitudinal edge 109a is welded directly to the housing base 101a, preferably over its entire length. The longitudinal edge 106a is welded directly to the contact metal sheet 112, preferably over its entire length. The contact metal sheet 112 is in turn connected to the cover 102 via the electrical conductor 133.

The energy storage element 100 preferably has a height in the range of 60 mm to 100 mm, and its diameter is preferably in the range of 20 mm to 50 mm. The cup-shaped housing part 101 typically has a wall thickness in the range of 0.1 mm to 0.3 mm in the central section 101b.

The energy storage element comprises an insulating element, an annular molded part made of plastic 150 with an L-shaped cross-section, which is applied to the edge that delimits the front side 104a and protects it from direct contact with the inner side 101d of the cup-shaped housing part 101. The energy storage element also comprises an annular insulating element 160 made of plastic, which rests on the inner side 101d of the cup-shaped housing part 101 in the area of the indentation 111 and protects it from direct contact with the electrical conductor 133. This can also be a partial section of the annular seal 103, which can be sufficiently high to also cover the indentation 111 from the inside.

As a result, the energy storage element 100 is excellently protected against short circuits even in the event of deformation of the housing as a result of an external mechanical force.

Instead of the ring-shaped molded part made of plastic 150 with an L-shaped cross-section, the edge which delimits the front side 104a can also be covered with an insulating tape, for example a Kapton tape 150. Ideally, this can already be applied to the edge when the winding is formed and protects the edge just as efficiently from direct contact with the inner side 101d.

3 shows an energy storage element 100 according to the invention with an air- and liquid-tight housing, which comprises a metallic, cup-shaped housing part 101 with a circular opening at the end and a cover 102 with a circular edge 102a, which closes the circular opening. The energy storage element further comprises an annular seal 103 made of an electrically insulating material, which encloses the circular edge 102a of the cover 102 and electrically insulates the cup-shaped housing part 101 and the cover 102 from one another.

The lid is shown in the form of a disc. However, multi-part lid assemblies are regularly used as lids, for example the ones in 17 depicted.

The cup-shaped housing part 101 comprises, in axial sequence, a base 101a, a central section 101b and a closure section 101c, wherein the central section 101b is cylindrical and in the central section 101b the winding jacket 104c of the composite body 104 designed as a winding is in contact with the inner side 101d of the cup-shaped housing part 101 and in the closure section 101c the annular seal 103 is in press contact with the cover 102 and the inner side of the cup-shaped housing part 101. The central section 101b and the closure section 101c are separated by an indentation 111 which runs annularly around the outer side 101e of the cup-shaped housing part 101.

The composite body 104 in the form of a cylindrical winding with the sequence anode/separator/cathode is not shown in detail here. Only the longitudinal edge 106a of the anode current collector 106, which emerges from the front side 104a of the composite body 104, and the longitudinal edge 109a of the cathode current collector 109, which emerges from the front side 104b of the composite body 104, can be seen. The longitudinal edge 109a is welded directly to the contact metal sheet 134, preferably over its entire length. The contact metal sheet 134 is in turn connected to the base 101a by welding. The longitudinal edge 106a is welded directly to the contact metal sheet 112, preferably over its entire length. The contact metal sheet 112 is in turn connected to the cover 102 via the electrical conductor 133.

The energy storage element 100 preferably has a height in the range of 60 mm to 100 mm, its diameter is preferably in the range of 20 mm to 50 mm. The cup-shaped housing part 101 typically has a wall thickness in the range of 0.1 mm to 0.3 mm in the central section 101b.

The energy storage element comprises an annular plastic part 170 as an insulating element, which laterally encloses the electrical conductor 133 and protects it from direct contact with the inner side 101d of the cup-shaped housing part 101 in the region of the indentation 111. The annular plastic part 170 is hollow-cylindrical and comprises a jacket 171 that is perpendicular to the contact metal sheet 112. One of its edges is designed as an outwardly directed annular collar 171 and sits on the contact metal sheet 112.

As a result, the energy storage element 100 is excellently protected against short circuits even in the event of deformation of the housing as a result of an external mechanical force.

4 shows several embodiments of a contact metal sheet 112 which is suitable for contacting the first longitudinal edge 106a of the current collector 106 of an energy storage element 100 according to the invention, said current collector emerging from the first terminal end face 104a.

Embodiment A shows a circular and essentially flat metal disk with a peripheral edge 102a as the contact metal sheet 112. This is characterized by a central hole 142 and three offset beads 141. Such a component can be used in the energy storage elements according to the 1 to 3 each for electrical contacting of the edge 106a of the anode current collector 106. However, it is also suitable for use as contact metal sheet 134 in the energy storage element according to 3 When using such a metal disk to contact the longitudinal edge 106a, the 1 to 3 The separate conductor 133 shown is absolutely necessary to bridge the distance to the contact metal sheet 102.

This is different in embodiment B. Here, the contact metal sheet 112 comprises a first section 112a, which can sit flat on the first longitudinal edge of the current collector emerging from the first terminal end face 104a and which then extends parallel to the end face 104a. In addition, however, it also comprises a second section 112b, which adjoins the first section 112a at an angle and via which the first section 112a is electrically connected to the cover 102. When using such a contact metal sheet, no separate conductor 133 is required. The contact metal sheet 112 is also characterized by a hole 142 and two beads 141. The contact metal sheet is preferably welded to the longitudinal edge of the respective current collector in these beads.

Embodiments C and D differ from embodiment B in that section 112a comprises three or four strips, respectively, which extend in different directions. Each of the strips has a bead 141. In addition, the sheet metal parts each have two holes 142.

The structure of the composite body 104 is based on 5 illustrated. The composite body 104 comprises the band-shaped anode 105 with the band-shaped anode current collector 106, which has a first longitudinal edge 106a and a second longitudinal edge parallel thereto. The anode current collector 106 is a foil made of aluminum. This comprises a band-shaped main region which is loaded with a layer of negative electrode material 107, and a free edge strip 106b which extends along its first longitudinal edge 106a and which is not loaded with the electrode material 107. The composite body 104 also comprises the band-shaped cathode 108 with the band-shaped cathode current collector 109, which has a first longitudinal edge 109a and a second longitudinal edge parallel thereto. The cathode current collector 109 is also an aluminum foil. It comprises a band-shaped main region which is loaded with a layer of positive electrode material 110, as well as a free edge strip 109b which extends along its first longitudinal edge 109a and which is not loaded with the electrode material 110. Both electrodes are shown individually in an unwound state.

The anode 105 and the cathode 108 are arranged offset from one another within the composite body 104, so that the first longitudinal edge 106a of the anode current collector 106 emerges from the first terminal face 104a and the first longitudinal edge 109a of the cathode current collector 109 emerges from the second terminal face 104b of the composite body 104. The offset arrangement is evident from the illustration at the bottom left. The two band-shaped separators 116 and 117 are also shown there, which separate the electrodes 105 and 108 from one another in the winding.

In the illustration at the bottom right, the composite body 104 is shown in wound form, as it is used in an energy storage element according to one of the 1 to 4 can be used. The electrode edges 106a and 109a emerging from the end faces 104a and 104b are clearly visible. The winding jacket 104c is formed by a plastic film.

6 shows further embodiments of the contact metal sheet 112, which is suitable for contacting the first longitudinal edge 106a of the current collector 106 of an energy storage element 100 according to the invention, which emerges from the first terminal end face 104a.

Of the designs BD of the 4 The embodiments BD shown here differ essentially only in that the section 112b is not folded in a Z-shape but is bent in a U-shape. Such contact metal sheets can be used in the energy storage elements according to the 1 to 3 Replace the contact metal sheet 112 and the electrical conductor 133.

7A-C shows a preferred embodiment of an energy storage cell according to the invention in a view obliquely from above ( 7A) , in a longitudinal section ( 7B) and in a view obliquely from below ( 7C ). The energy storage cell 100 has the shape of a cylindrical round cell. The housing of the energy storage cell 100 is formed by a cup-shaped housing part 101 and a cover. The cover comprises a cover plate 102a, which has the shape of a perforated plate, and a connection pole 102b in the center of the cover component.

As shown in the sectional view in 2B As can be seen, the winding-shaped composite body 104 is located inside the energy storage cell 100, which is formed from the wound electrode strips with separator strips in between.

In 2C the underside of the energy storage cell 100 is shown, which is formed by the housing base 101a. In the housing base 101a, three star-shaped weld impressions in the form of beads 161 are arranged, which appear as a depression on the outside and as an elongated elevation on the inside. The longitudinal edge of the respective current collector sits on the inside of these beads 161 and in the area of these beads the current collector is preferably welded directly to the housing base.

The preferred material for the housing base 101a and the entire cup-shaped housing part 101 is aluminum.

In the present example, two safety functions are integrated into the housing base 101a. Firstly, there is an opening in the center of the housing base 101a that is closed with a metallic membrane 114. In the event of excess pressure occurring due to a malfunction of the cell, this membrane 114 is used to equalize the pressure by either bursting the membrane open or blowing it off due to the pressure. In this way, any gas that may have formed inside the cell can escape through the opening in the housing base 101a (primary safety).

In addition, a further safety function is provided in the housing base 101a, which is implemented by three star-shaped grooves 166. These grooves 166 represent weakenings in the structure of the housing base 101a and thus form predetermined breaking points in the event of excess pressure occurring inside the cell (secondary safety). In this embodiment, the grooves 166 are located on the inner side of the housing base 101a and are therefore in 7C shown as dashed lines. The grooves 166 can be implemented, for example, as three scoring lines. The star-shaped arrangement of the scoring lines is further developed by a part-circular connection of the scoring lines or the grooves 166. In the event of a correspondingly high overpressure, the housing base 101a tears open along the grooves 166 and the part-circular connection of these grooves, so that an outlet opening with a comparatively large cross-section is created, through which any gas formed inside the housing can quickly escape.

8A ,B shows an enlarged view of the frontal areas of the embodiment of the energy storage cell 100 according to 7 . Out of 8A details of the front side with the cover 102 are shown. The cover 102 comprises the cover plate 102a with a central opening and with the connection pole 102b arranged in the center of the cover plate 102a. In this embodiment, for example, the connection pole 102b can form the negative pole and the surrounding cover plate 102a can form the positive pole of the energy storage cell 100.

Below the connection pole 102b is the contact metal sheet 112, which sits on the free edge strip 106b of the spirally arranged anode current collector of the negative electrode and is welded to it. The contact metal sheet 112 is electrically connected to the connection pole 102b, which is formed from two metallic components, in particular by welding. The cover plate 102a is electrically insulated from the contact metal sheet 112 by an O-ring-shaped insulating disk 177. Furthermore, an electrically insulating casting compound 113 is located in a gap between the connection pole 102b and the cover plate 102a.

8B shows details of the opposite end face of the energy storage cell 100. The free edge strip 109b of the cathode current collector is directly electrically connected, in particular welded, to the housing base 101a on this end face of the energy storage cell 100. The jacket of the cup-shaped housing part 101 provides electrical contact with the metallic cover plate 102a on the opposite end face, so that the positive potential of the cell can also be tapped on the upper end face of the energy storage cell 100.

At the 8B The preferred safety functions of the cell against excess pressure according to the invention can be seen on the lower front side of the energy storage cell 100 shown. The primary safety is formed by the metallic membrane 114, which closes a central circular opening 155 in the housing base 101a. The secondary safety is formed by the grooves 166, whereby in this illustration one of the three star-shaped grooves 166 can be seen in section. The grooves 166, which are located on the inside of the housing base 101a, represent a defined weakening structure of the housing base, so that when a relatively high excess pressure develops inside the cell, these structures open and gas can escape.

The 8 The preferred design of an energy storage cell 100 according to the invention illustrated allows a reduced number of parts in the upper region of the energy storage cell ( 8A) , with the negative and positive terminals of the cell being arranged in this upper area. In particular, this design eliminates the need for additional arresters due to the one-piece construction of the connection pole 102b.

The direct contact of the longitudinal edge of one of the electrode strips on the side of the housing base ( 8B) serves to ensure the particularly compact design of the cell, so that no dead volumes are required for the various functions of the cell.

Furthermore, the direct contact between the longitudinal edges of the electrode strips results in improved heat dissipation and a reduction in internal resistance.

In addition, the design of this cell generally allows for the formation of longer coils and thus a greater energy density of the resulting energy storage cell.

In this embodiment, the upper front side of the energy storage cell 100 is designed to be as compact as possible. If gases are formed inside the cell and lead to an increase in pressure, these gases are inevitably directed into the lower area of the cell, in which the safety functions for pressure equalization are arranged. Overall, such a cell therefore has a very good level of safety.

9A ,B shows a detailed view of the connection pole 102b from the 7 and 8 in a view obliquely from above ( 9A) and in a sectional view ( 9B) . The connection pole 102b can be composed of two metallic components. The upper area (pole upper part) 1020 does not necessarily have to be made of the same metal as the lower area (pole lower part) 1021. The upper area 1020 has a beveled, circumferential upper edge. As shown in the sectional view according to 4B As can be seen, an externally circumferential welding shoulder 1021a and a central, downwardly projecting pin 1021b are provided in the lower region 1021. The pin 1021b expediently engages in a correspondingly provided recess in the center of the contact metal sheet 112 and thus ensures a good fit of the connection pole 102b.

10A ,B shows the O-ring-shaped insulating disc 177 in a complete view obliquely from above ( 10A) and in a cut view ( 10B) . The insulating disk 177 has the function of electrically insulating the preferably positively polarized cover plate 102a from the components components of the energy storage cell 100 with reversed polarity. In addition, the insulating disk 177 also ensures a liquid-tight and airtight closure of the housing.

In the preferred embodiment of the insulating disk 177 shown here, the insulating disk is made of two different materials. The outer region 177a of the insulating disk 177 is preferably made of a particularly strong plastic material, for example PBT (polybutylene terephthalate). The inner region 177b is preferably made of a somewhat more flexible and, above all, particularly heat-resistant plastic, for example PET (polyethylene terephthalate). The outer region 177a thus ensures particular mechanical stability. The inner region 177b ensures flexibility and is particularly resistant to the hot-applied potting compound 13 when assembling the energy storage cell.

It is particularly advantageous if the inner circumference of the O-ring-shaped insulating disk 177 has a circumferential thickening, which further supports the stability of the components in the front area of the mounted energy storage cell.

When assembling the energy storage cell, the cell is initially temporarily sealed by inserting the insulating disk 177 in the cover area of the cell until the subsequently introduced potting compound 113 has hardened to completely seal the cell. Furthermore, the insulating disk 177's special shape allows axial support of the coil-shaped composite body 104, for example when testing the cell. If the cell is deformed laterally, the shape of the insulating disk 177 also offers space for any deformation of the contact metal sheet 112 that may occur. Finally, the shape of the insulating disk 177 makes it possible to reduce the volume of the potting compound 113 and the amount of air bubbles that may be trapped during the potting when assembling the energy storage cell.

As a possible alternative to such an insulating disk, an insulating sealing bead, comparable to a silicone bead, can be added. This can also ensure a tight seal. The insulating disk 177, in particular in the embodiment illustrated here, offers the various advantages mentioned.

11A ,B shows a preferred embodiment of the contact metal sheet 112, which is provided for contacting the free edge of the current collector of the respective electrode in the upper region of the energy storage cell. 11A shows a top view of the disc-shaped contact metal sheet 112. 11B shows a section through the contact metal sheet 112 in a view from below, i.e. on the side of the contact metal sheet that faces the composite body 104 inside the energy storage cell.

Comparable to the beads 161 of the housing base 101a, the contact metal sheet 112 also has three star-shaped beads 112d, which extend outwards ( 11A) as a depression and inwards ( 11B) appear as an elongated elevation. The beads 112d can be embossed, for example, and have a depth of 0.25 mm, for example. When the cell is assembled, the beads 112d are in contact with the respective longitudinal edge of an electrode strip of the composite body to be contacted via them. The contact metal sheet 112 is preferably welded to the respective longitudinal edge of the electrode strip via the beads 112d.

In the center of the contact metal sheet 112 there is a recess 112e. The recess 112e serves to accommodate the connection pole 102b, in that the central pin 1021b of the connection pole 102b engages in the recess 112e. In this way, the connection pole 102b can be easily positioned and fixed on the contact metal sheet 112, so that the connection pole 102b can be welded on without any problems.

Furthermore, in the particularly preferred embodiment of the contact metal sheet 112 shown here, further star-shaped narrow depressions 112f are provided, which are located on the inward-facing side of the contact metal sheet 112. In this exemplary embodiment, a total of nine of these depressions 112f are provided as narrow grooves arranged in a star shape. The grooves can have a depth of 0.1 mm, for example. The depressions 112f serve to better distribute the electrolyte within the cell.

Furthermore, in this preferred embodiment, the contact metal sheet 112 has an embossed peripheral edge 112g, which is arranged as a predetermined bending point, in particular with the ridge pointing downwards. This predetermined bending point facilitates the assembly of the housing of the energy storage cell.

In preferred embodiments, the contact metal sheet 112 is made of aluminum, for example from an aluminum sheet with a material thickness of 0.3 mm.

12 shows a detailed view of the housing base 101a of the energy storage cell with the star-shaped, inwardly projecting beads 161, which are designed in particular as welded impressions for contacting the coil-shaped composite body. The star-shaped arrangement with three beads 161 is particularly advantageous for the assembly of the cell due to its rotational symmetry.

The central opening 155 in the housing base 101a is covered by a metallic membrane 114 and serves as primary protection for the cell in the event of excess pressure occurring. In particular, it is intended that the opening 155 is initially used to fill the cell with electrolyte during the manufacture of the cell before the opening 155 is closed with the metallic membrane 114.

For a precise fit of the metallic membrane 114 for closing the central opening 155, a circumferential recess 1010b is preferably provided which surrounds the central opening 155.

Furthermore, in this embodiment, three weakening structures arranged in a star shape are provided in the form of the inwardly open grooves 166, which are connected to one another by a partially circular connecting line 1010c. These weakening structures 166 and 1010c serve as secondary protection against internal overpressure. As an alternative to attaching the weakening structures from the inside to the housing base, such weakening structures, for example scoring lines, can also be attached from the outside.

On the outside of the housing base 101a, one or more labeling fields 1010a can also be provided, which can be used for the attachment of various written information.

13A-C shows in exploded views the various components of a preferred embodiment of an energy storage cell according to the invention. 13A The components of the housing are shown with the housing cup 101, the connection pole 102b, the O-ring-shaped insulating disk 177, the cover plate 102 with the central recess into which the connection pole 102b engages, and the potting compound 113. Below the housing cup 101, the closure for the energy storage cell in the form of the metallic membrane 114 is shown, whereby this closure is attached after the assembled cell has been filled with the electrolyte 115 shown schematically here.

13B shows the coil-shaped electrode-separator composite body 104 and the contact metal sheet 112 to be attached to it. The composite body 104 can be produced in a manner known per se by winding the electrode strips and the separators, in particular on a winding machine. To complete the winding shape, the outermost winding turn can preferably be bent inwards by, for example, 30° to 45° using a conical pressure piece, so that the winding shape is stabilized. An adhesive tape 118 ( 13C ), for example made of polypropylene, which, in addition to the stabilizing function, may also perform an electrically insulating function in the cell. After this stabilization of the wound composite body 104, the disk-shaped contact metal sheet 112, which is made of aluminum, for example, can be placed loosely on the upper end face of the coil and fixed with a particularly stable adhesive tape 119 made of polyimide, for example. A tape made of Kapton® with a thickness of 50 µm can be used for this, for example.

The composite body 104 with the attached contact metal sheet 112 can then be inserted into the cup-shaped housing part 101. After an alignment of the beads in the housing base and in the contact metal sheet, possibly with the aid of a camera, the arrangement can be pressed together using suitable pressing tools and can be laser-welded simultaneously or sequentially from above and below to contact the longitudinal edges of the electrode strips with the respective beads. The connection pole 102b can then be placed on the contact metal sheet 112 and welded on.

14A ,B shows details of the manufacturing of the cover assembly of the cell. From 14A shows a detailed view of the welding of the connection pole 102b onto the contact metal sheet 112, whereby the laser can act obliquely or vertically, in particular in the area of the circumferential welding shoulder 1021a of the connection pole 102b. In 14B it is shown how the insulating disk 177 can then be inserted and pressed to the correct height before the cover plate 102a is placed on top and welded from an angle, vertically or horizontally to the cup-shaped housing part (not shown here). The connection pole 102b can now be pressed to the correct height in relation to the cell shoulder, which is formed by the upper side of the cover plate 102a. The distance provided for this can be, for example, 1 mm between the top of the connection pole 102b and the top of the cover plate 102a. The gap between the cover plate 102a and the connection pole 102b is filled with a potting compound 113 in order to seal this part of the energy storage cell in an airtight and liquid-tight manner.

The energy storage cell can then be transferred to an oven to set the potting compound 113 and to bake out the residual moisture of the coil-shaped composite body.

15 illustrates the final filling with electrolyte 115, which is filled from the underside of the energy storage cell 100 (in this illustration at the top) through the opening 101b in the housing base 101a. Finally, the metallic membrane 114 is applied as a closure on the opening in the housing base 101a or as a closure on the central opening 155. For this purpose, for example, a vertical laser beam can be used.

16 illustrates an alternative way to mount the cover assembly. 16A shows the contact metal sheet 112 with the connection pole 102b attached to it in a sectional view obliquely from below. 16B shows the upper front side area of the cell in a longitudinal section.

In this alternative manufacturing process, the connection pole 102b is welded in advance to the contact metal sheet 112. Friction welding or friction stir welding can be used for this purpose.

When designing the contact metal sheet 112 in this embodiment, the star-shaped beads 112d of the contact metal sheet 112 can be shortened if necessary, since they are covered by the connection pole 102b during the subsequent welding of the electrode-separator composite body. Overall, therefore, somewhat less welding surface is available for contacting the longitudinal edge of the respective electrode strip with the contact metal sheet 112. However, this design can offer advantages for assembly.

Since it may be easier to attach the connection pole 102b directly to the contact metal sheet 112 outside the housing cup assembly, a central recess in the contact metal sheet and a corresponding pin on the connection pole 102b may be dispensed with.

The further assembly of the energy storage cell with the connection pole 102b, which is already welded directly onto the contact metal sheet 112, does not differ in principle from the previously described manufacturing process for the energy storage cell 100.

17 shows an example of a cover assembly 202 which can be used as a cover in an energy storage element according to the invention according to 1 or 2 or 3 can be installed.

This includes the metal disk 213 with the metallic membrane 214, which bulges outwards or bursts in the event of excess pressure within the housing. The metal disk 213 with the membrane 214 is in electrical and direct contact with the metallic pole cap 217, which closes off the cover assembly 202 from the outside. It is also in electrical contact with an inner metallic contact disk 215, but only via the metallic membrane 214. Otherwise, the metal disk 213 and the contact disk 215 are electrically insulated from one another by the ring-shaped insulator 216. If the membrane 214 bulges outwards as a result of excess pressure, which can act directly on the membrane via the opening 215a, the electrical contact between the metal disk 213 and the contact disk 215 breaks off. At high pressures, the membrane can also burst. The arresters 113 of the 1 to 3 The cells shown can be welded to the contact disk 213.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• US 20050277019 A1 [0013]
• WO 2017215900 A1 [0014, 0197]
• EP 3916841 A1 [0015]
• EP 3916828 A1 [0015]
• EP 3916827 A1 [0015]
• EP 3916829 A1 [0015]
• EP 3916870 A1 [0015]
• EP 3916869 A1 [0015]
• EP 3916877 A1 [0015]
• EP 3965196 A1 [0015]
• EP 3916868 A1 [0015]
• WO 2021255238 A1 [0124]
• WO 2020239512 A1 [0135]

Cited non-patent literature

• Zhang et al., “SODIUM-ION BATTERY ANODES: STATUS AND FUTURE TRENDS”, EnergyChem 1 , 100012 (2019) from 2019 in [0069]

Claims (14)

Secondary energy storage element (100) with the following features: a. It comprises a cathode (108) and an anode (105) as electrodes, which are parts of a composite body (104) in which they are present in the sequence cathode (108) / separator or solid electrolyte layer (116) / anode (105), separated by a separator or solid electrolyte layer (116), b. the cathode (108) comprises a cathode current collector (109) and a positive electrode material (110), c. the anode (105) comprises an anode current collector (106) and a negative electrode material (107), d. the cathode current collector (109) has - a main region which is loaded on both sides with a layer of the positive electrode material (110), and - a free edge strip (109b) which extends along an edge (109a) of the cathode current collector (109) and which is not loaded with the positive electrode material (110), and/or the anode current collector (106) has - a main region which is loaded on both sides with a layer of the negative electrode material (107), and - a free edge strip (106b) which extends along an edge (106a) of the anode current collector (106) and which is not loaded with the negative electrode material (107), e. the cathode (108) and the anode (105) are designed and/or arranged relative to one another within the composite body (104) such that the free edge strip (109b) of the cathode current collector (109) emerges from one side (104b) of the composite body (104) and/or the free edge strip (106b) of the anode current collector (106) emerges from another side (104a) of the composite body (104), and f. the energy storage element comprises a first contact metal sheet (112) which is in direct contact with one of the free edge strips (106b) and/or a second contact metal sheet (101a) which is in direct contact with the other of the free edge strips (109b), wherein g. the electrodes (105, 108) comprise at least one ion type from the group consisting of sodium ions, potassium ions, calcium ions, magnesium ions and aluminum ions, which are exchanged between the cathode (108) and the anode (105) during charging and discharging of the secondary energy storage element (100). Energy storage element according to claim 1 with the following additional features: a. The electrodes (105, 108) and the current collectors (106, 109) as well as the layers of the electrode materials (107, 110) are band-shaped, b. It comprises at least one band-shaped separator (116) or at least one band-shaped solid electrolyte layer, c. the composite body (104) is in the form of a coil in which the electrodes (105, 108) and the at least one separator (116) are wound around a winding axis, the composite body (104) comprising a first and a second terminal end face (104a, 104b) and a winding casing (104c) and the free edge strip (109b) of the cathode current collector (109) emerges from the first end face (104b) and/or the free edge strip (106b) of the anode current collector (106) emerges from the second end face (104a), d. It comprises a housing, in particular a metal housing, comprising a housing casing or side walls and a base (101a) and a cover (102) on the end faces, and e. In the housing, the composite body (104) designed as a winding is aligned such that the winding jacket (104c) rests against the inner side (101d) of the housing jacket or the side walls. Energy storage element according to claim 1 with the following additional features: a. The composite body (104) is in the form of a prismatic stack in which the cathode (108) and the anode (105) are stacked together with further cathodes (108) and anodes (105). b. The electrodes (105, 108) and the current collectors (106, 109) as well as the layers made of the electrode materials are polygonal, in particular rectangular. c. It comprises at least one band-shaped or polygonal, in particular rectangular, separator (116) or at least one band-shaped or polygonal, in particular rectangular, solid electrolyte, d. The stack is enclosed by a prismatic housing. Energy storage element according to one of the preceding claims with at least one of the following additional features: a. The energy storage element (100) is a sodium ion cell. b. The energy storage element comprises a sodium ion cell. c. The energy storage element comprises one of the following electrolytes: - NaClO ₄ dissolved in at least one organic solvent, in particular in PC or in a carbonate mixture from the group containing EC/DEC/FEC and PC/FEC; - NaPF ₆ and/or NaTFSI dissolved in at least one organic solvent, in particular in PC or in a carbonate mixture from the group containing EC/DEC/FEC, EC/PC, EC/DEC, FEC/EMC and PC/FEC or in an ether mixture such as THF/mTHF; - NaFSI and/or NaTFSI and/or NaTDI dissolved in at least one organic solvent, in particular in 1,4-dioxane (DX) and/or 1,3-dioxolane (DOL) and/or dimethyl ether (DME); - NaFSI and/or NaTFSI and/or NaTDI dissolved in at least one organic solvent, in particular in dimethyl carbonate (DX) and/or tris(2,2,2-trifluoroethyl)phosphate (TFP); - NaN(SO ₂ F) ₂ dissolved in at least one organic solvent, in particular in 1,4-dioxane (DX) and/or 1,3-dioxolane (DOL) and/or dimethyl ether (DME); - NaBF ₄ dissolved in at least one organic solvent, in particular in tetraethylene glycol dimethyl ether (TEGDME) and/or in ACN and/or in PC and/or GBL. Energy storage element according to one of the preceding claims with at least one of the following additional features: a. The side of the composite body (104a, 104b) from which the free edge strip (109b) of the cathode current collector (109) or the free edge strip (106b) of the anode current collector (106) emerges is formed by an edge of the separator (116), in the case of an energy storage element with a wound composite body (104) in particular a longitudinal edge of the separator (116). b. The edge or longitudinal edge of the separator (116) which forms the side, in particular the front side, is ceramically reinforced. Energy storage element according to one of the preceding claims with the following additional feature: a. The anode current collector (106) and/or cathode current collector (109) consists of aluminum or an aluminum alloy. Energy storage element according to one of the preceding claims with at least one of the following additional features: a. In the free edge strip (109b) of the cathode current collector (109) and/or in the free edge strip (106b) of the anode current collector (106), the surface of the cathode current collector (109) and/or of the anode current collector (106) is coated with a supporting material which is more thermally stable than the surface coated therewith. b. The non-metallic material is a ceramic material, a glass-ceramic material or a glass. c. The ceramic material is aluminum oxide (Al ₂ O ₃ ), aluminum hydroxide (Al(OH) ₃ ), aluminum oxide hydroxide (AlOOH), silicon oxide, in particular silicon dioxide (SiO ₂ ), titanium oxide (TiO ₂ ), titanium nitride (TiN), titanium aluminum nitride (TiAlN) or titanium carbonitride (TiCN). Energy storage element according to one of the Claims 2 or 4 - 7 with at least one of the following additional features: a. It comprises an air- and liquid-tight housing which has a metallic, cup-shaped housing part (101) with the base (101a) and a terminal circular opening and a lid (102) with a circular edge (102a) which closes the terminal circular opening. b. The composite body (104) is arranged in an axial orientation in the cup-shaped housing part, with the first end face (104a) pointing in the direction of the lid (102) and the second end face (104b) pointing in the direction of the base (101a), optionally being in direct contact with the base (101a). c. It comprises an annular seal (103) made of an electrically insulating material, which encloses the circular edge (102a) of the cover (102) and electrically insulates the cup-shaped housing part (101) and the cover (102) from one another. d. The cup-shaped housing part (101) comprises an inner side (101d) and an outer side (101e) and, in axial sequence, the base (101a), a central section (101b) and a closure section (101c), wherein - the central section (101b) is cylindrical and in the central section (101b) the winding jacket (104c) of the composite body (104) designed as a winding is in contact with the inner side (101d) of the cup-shaped housing part (101), and - in the closure section (101c) the annular seal (103) is in press contact with the cover (102) and the inside of the cup-shaped housing part (101). e. The central section (101b) and the closure section (101c) are separated by an indentation (111) which runs in a ring around the outside (101e) of the cup-shaped housing part (101). f. The contact metal sheet (112) is connected to the free edge strip (106b) of the current collector emerging from the first terminal end face (104a) by welding and is electrically connected to the cover (102), preferably also by welding. g. It comprises at least one insulating element (150; 160; 170; 180) made of an electrically insulating material which protects the contact metal sheet (112) and/or the free edge strip (106b, 109b) of the current collector (106, 109) emerging from the end face (104a) and/or a separate electrical conductor (133) fixed to the contact metal sheet (112) from direct contact with the inner side (101d) of the cup-shaped housing part (101), in particular in the region of the indentation (111). Energy storage element according to one of the Claims 1 until 7 with at least one of the following additional features: a. It comprises an air- and liquid-tight housing which has a metallic, cup-shaped housing part (101) with a base (101a) and an end opening, as well as a lid (102) which closes the end opening. b. The lid (102) comprises a metallic cover plate (102a) and a connection pole (102b) which is guided through an opening in the cover plate (102) and is electrically insulated from the cover plate (102). c. The composite body (104) is arranged in the cup-shaped housing part, with one side (104a) of the composite body pointing in the direction of the cover (102) and a second side (104b) in the direction of the base (101a), optionally being in direct contact with the base (101a). d. The cathode (108) and the anode (105) are designed and/or arranged relative to one another within the composite body (104) in such a way that the free edge strip (109b) of the cathode current collector (109) emerges from the side (104b) of the composite body (104) and the free edge strip (106b) of the anode current collector (106) emerges from one side (104a) of the composite body (104), and e. The contact metal sheet (112) sits directly on the free edge strip of one of the current collectors emerging from one of the sides of the composite body and is connected to it by welding. f. The contact metal sheet (112) is either electrically connected to the connection pole (102b) guided through the opening in the cover plate (102a), preferably directly welded to the connection pole (102b), or the connection pole (102b) is part of the contact metal sheet (112). g. The connection pole (102b) is electrically insulated from the cover plate (102) by a hardened casting compound (113) made of an electrically insulating plastic material. Energy storage element according to claim 9 with the following additional feature: a. The edge strip of the cathode current collector (109) or the anode current collector (106) which is not in direct contact with the contact metal sheet (112) is electrically connected to the housing base (101a), preferably welded directly to the housing base (101a). Energy storage element according to one of the Claims 9 or 10 with at least one of the following additional features: a. Between the cover plate (102) and the contact metal sheet (112) there is an annular gap which is filled with the casting compound (113). b. The annular gap is limited radially outwards by an O-ring-shaped insulating disk (177) made of an electrically insulating plastic material. Energy storage element according to one of the Claims 9 until 11 with the following additional features: a. the housing base (101a) of the cup-shaped housing part (101) has a primary protection against internal overpressure in the form of an opening (155) which is closed by means of a metallic membrane (114), b. the housing base (101a) of the cup-shaped housing part (101) has a secondary protection against internal overpressure in the form of at least one groove (166) on its inside or its outside. Battery comprising at least two energy storage elements according to one of the preceding claims, which are connected in parallel and/or in series. battery after claim 13 , characterized in that it has a nominal voltage of 12V or 24V.

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