DE102022210846A1 - Battery for an electrically powered motor vehicle - Google Patents

Abstract

The invention relates to a battery (2) for an electrically powered motor vehicle. This comprises a battery housing (4) with a housing base (6) and with a housing cover (8), as well as a battery cell (10) arranged in the battery housing (4), wherein the battery cell (10) is connected to the housing base (8) by means of a first Velcro connection (12) and/or to the housing cover (8) by means of a second Velcro connection (14), and wherein a thermally conductive colloid, a thermally conductive gel (24), and/or a thermally conductive paste is introduced between Velcro units (16) of the first Velcro connection (12) and/or between Velcro units (16) of the second Velcro connection (14). Furthermore, the invention relates to an electrically powered motor vehicle with such a battery (2).

Description

The invention relates to a battery, in particular a traction battery, for an electrically powered motor vehicle, which has a battery housing with a housing base and a housing cover, as well as a battery cell arranged in the battery housing.

An electrically powered motor vehicle typically has a traction battery (high-voltage battery, HV battery) which supplies an electric motor with energy to drive the motor vehicle. An electrically powered motor vehicle is understood to mean in particular an electric vehicle which stores the energy required for propulsion only in the traction battery (BEV, battery electric vehicle), an electric vehicle with a range extender (REEV, range extended electric vehicle), a hybrid vehicle (HEV, hybrid electric vehicle), a plug-in hybrid vehicle (PHEV, plug-in hybrid electric vehicle) and/or a fuel cell vehicle (FCEV, fuel cell electric vehicle), which temporarily stores the electrical energy generated by a fuel cell in the traction battery.

Such a traction battery typically comprises a large number of battery cells that are connected in series and/or parallel to one another. For example, the battery cells are combined in modules, with the battery cells only being connected to one another within the module, and the modules being connected to one another in series and/or parallel to one another. Alternatively, in the so-called Cell2Pack or Cell2Car design, the battery cells are connected directly together, i.e. not combined into modules in advance.

For example, the individual battery cells are glued together with adhesives or gap fillers during assembly in a module or pack. Furthermore, a so-called gap pad is typically arranged between adjacent battery cells as an intermediate element, which compensates for the volume changes of the battery cell stack during charging and discharging (so-called cell breathing). The gap pads also compensate for the age-related increase in thickness of the battery cells over their service life (so-called cell swelling). Furthermore, the battery cells can be glued to a cooling connection side with a gap filler.

Due to the way the battery cells or modules are attached, for example by welding or using a bearing, cooling is disadvantageously difficult.

From the US 2007/0224498 A1 It is known to provide the mutually facing front sides of the battery cells with Velcro surfaces and to stack them to form a Velcro-connected cell stack.

In the WO 2020/192196 A1 It is disclosed that a cooling gel can be introduced between a cooling plate and the battery cells.

The invention is based on the object of specifying a particularly suitable battery for an electrically powered motor vehicle, which enables the battery cells to be cooled as effectively as possible and/or which is as stable and crash-proof as possible. Furthermore, an electrically powered motor vehicle with such a battery is to be specified.

With regard to the battery, the object is achieved according to the invention by the features of claim 1. With regard to the electrically powered motor vehicle, the object is achieved according to the invention by the features of claim 8. Advantageous embodiments and further developments are the subject of the subclaims. The statements in connection with the battery also apply mutatis mutandis to the motor vehicle and vice versa.

The battery is intended and designed for an electrically powered motor vehicle. In particular, the battery is a traction battery of the motor vehicle. The battery therefore supplies a (traction) electric motor to drive the motor vehicle with electrical energy. The battery is suitably a secondary battery.

The battery has a battery housing, also referred to as a housing for short, with a housing base and a housing cover opposite the housing base, in particular extending parallel to it. A battery cell, in particular a lithium-ion battery cell, is arranged in the battery housing, thus between the housing base and the housing cover. Several such battery cells are expediently arranged in the battery housing between the housing base and the housing cover. In particular, the battery cell or cells are inserted directly into the battery housing according to the Cell2Pack or Cell2Car design, with the battery cells preferably being arranged next to one another in a row.

Here and in the following, the side of the respective battery cell facing the housing cover is referred to as the top side and the side facing the housing bottom is referred to as the bottom side.

The battery cell is (or each battery cell is) connected to the housing base using a first Velcro connection. The battery cell is therefore fixed and held on the housing base using the first Velcro connection. The first Velcro connection is formed using two mutually complementary Velcro units, in particular using two Velcro strips, one of which is attached, in particular glued, to the underside of the battery cell and the other is attached, in particular glued, to the side of the housing base facing the battery cell.

Alternatively or preferably in addition to this, the battery cell (or each battery cell) is connected to the housing cover using a second Velcro connection. The battery cell is therefore fixed and held on the housing cover using the second Velcro connection. The second Velcro connection is formed in an analogous manner using two (further) Velcro units that complement each other, in particular using two (further) Velcro strips, one of which is attached, in particular glued, to the top of the battery cell and the other is attached, in particular glued, to the side of the housing cover facing the battery cell.

Here and in the following, "Velcro-connected" or "Velcro connection" is to be understood as a reversibly detachable positive and/or non-positive connection between the Velcro units. The Velcro connection (the Velcro fastener) is based on the principle of Velcro fruits. The Velcro units therefore have Velcro fastener elements that complement each other and are held together in a positive and/or non-positive manner in the Velcro connection. The complementary Velcro units can, for example, be designed as a hook and loop tape (felt tape, velour tape), or as a mushroom head tape and loop tape, or a mushroom head tape and mushroom head tape, or as a hook tape and mushroom head tape.

Furthermore, a thermally conductive colloid is introduced between the two Velcro units of the first Velcro connection and/or between the two Velcro units of the second Velcro connection. A colloid is a mixture of particles, in particular solid particles, or drops in a dispersion medium, whereby the dispersion medium can be in the form of a solid, a gas or a liquid. The particles or drops are distributed in the dispersion medium, in particular homogeneously. The particles or drops preferably have a diameter between 1 nm and 1000 nm, particularly preferably a diameter between 10 nm and 500 nm.

Alternatively or in addition to the colloid, a thermally conductive gel (thermally conductive gel, thermally conductive gel, cooling gel) and/or a, in particular non-flowable, thermally conductive paste is introduced between the two Velcro units of the first Velcro connection and/or between the two Velcro units of the second Velcro connection.

In summary, thermally conductive colloid, thermally conductive gel or thermal paste or a mixture thereof is introduced into the first Velcro connection and/or the second Velcro connection. In other words, the gel, colloid or thermal paste is arranged in an (intermediate) space which is formed between the complementary Velcro units in the assembled state. In particular, this intermediate space is filled with the gel, colloid or thermal paste.

For example, the thermal paste is hardened so that the connection of the Velcro units is comparatively safe and stable. In contrast, with a paste-like thermal paste, i.e. a non-hardened thermal paste, as well as with gel, a non-destructive opening (release) of the first or second Velcro connection is advantageously possible, so that maintenance, in which the housing cover and/or the housing base is released from the battery cell, is simplified.

In summary, the first and/or second Velcro connection allows the battery cell to be joined to the housing in a comparatively simple manner. The (housing) cover or the (housing) base is held relatively securely in place by the first or second Velcro connection. The space formed by the Velcro units is also advantageously used for the thermally conductive colloid, for the (heat-conducting) gel or for the thermal paste. The gel or the thermal paste improves heat transfer from the battery cell to the housing base or to the housing cover.

In an expedient embodiment, the thermal conductivity of the colloid, the gel and/or the thermal paste is greater than 4 W/(m K), in particular greater than 7 W/(m · K). Preferably, the thermal conductivity of the gel is between 4 W/(m · K) and 20 W/(m K), in particular between 7 W/(m · K) and 13 W/(m · K).

The gel is, for example, a polymer-solvent mixture. In particular, the gel is a viscoelastic fluid, whereby the polymer, in particular a solid one, is expediently a sponge-like, forms a three-dimensional network in whose pores the solvent is absorbed. For example, a gel with macromolecular polymers is used. In particular, these polymers have an extension or diameter that is greater than 1000 nm.

For example, a block polymer, in particular a styrene block copolymer or an ester block copolymer, is used for the polymer of the gel. Oils or organic solvents are suitably used as solvents or swelling agents for producing the gel. As a concrete example, styrene-butadiene-styrene is used as a block copolymer with mineral oil as a plasticizer. The proportion of oil is selected according to a desired or specified viscosity and is between 30 vol.% and 85 vol.%.

According to a suitable embodiment, the thermally conductive gel has a viscosity which - based on room temperature (20°C) - is between 150,000 mPa·s (millipascal second) and 5,000,000 mPa·s, in particular between 500,000 mPa·s and 2,000,000 mPa·s, preferably between 500,000 mPa·s and 1,000,000 mPa·s. Preferably, the colloid also has a viscosity - based on room temperature (20°C) - which is between 150,000 mPa·s (millipascal second) and 5,000,000 mPa·s, in particular between 500,000 mPa·s and 2,000,000 mPa·s, preferably between 500,000 mPa·s and 1,000,000 mPa·s.

Even when a device containing the battery is in operation, particularly an electrically powered motor vehicle, and vibrations or shocks may occur, the thermally conductive colloid, the gel (and similarly the more viscous thermal paste) is held relatively securely in the spaces between the Velcro units. This means that the gel or colloid is prevented from escaping from the Velcro area due to such viscosity, or the risk of this is at least reduced.

According to an advantageous embodiment, the first and/or the second Velcro connection is designed such that a head tensile load for opening the first Velcro connection, i.e. for releasing the connection of the battery cell from the housing base due to the first Velcro connection, or for opening the second Velcro connection, i.e. for releasing the connection of the battery cell from the housing cover due to the second Velcro connection, is in each case greater than 5 MPa (megapascals). In other words, a tensile load must be applied in a direction perpendicular to the Velcro units of the first or second Velcro connection, which is greater than 5 MPa, so that the first and/or the second Velcro connection is opened. In this way, a particularly operational and crash-safe as well as stable battery is realized, in particular for an electrically powered motor vehicle.

Preferably, the first and/or the second Velcro connection is further designed such that its shear strength is in each case greater than 5 MPa. The pressures and line loads for dissolving the Velcro connection by means of a peeling movement are preferably dimensioned to be significantly smaller than the head tensile load and/or shear strength.

Suitably, the Velcro unit of the first and/or the Velcro units of the second Velcro connection are each made of or comprise a polymer, in particular polypropylene, polyamide, polyaramide, polyester and polyolefin. This variant of the Velcro units is advantageously comparatively weight- and cost-saving.

Alternatively, the Velcro unit of the first and/or the Velcro units of the second Velcro connection are each made of or comprise a metal or an alloy, such as steel. Due to the metal or the alloy, the Velcro units each have a comparatively high thermal conductivity, so that cooling of the battery cell is further improved. In addition, with Velcro units made of or with metal or made of or with an alloy, it is comparatively easy to achieve high tensile and/or shear strengths, in particular greater than 5 MPa in each case.

In a practical embodiment, the housing base and/or the housing cover can be cooled. Preferably, the housing base and/or the housing cover can be actively cooled using a cooling device. In particular, the housing base and/or the housing cover each have a cooling channel for a cooling medium. In other words, a cooling channel for controlling the temperature of the battery cell is preferably integrated into the housing base and/or the housing cover. The housing base or the housing cover therefore serves as a heat sink for the heat conducted away from the battery cell using the (cooling) gel, the colloid or the thermal paste and/or the Velcro units.

A further aspect of the invention relates to an electrically powered motor vehicle with a battery that is designed according to one of the variants presented above. In particular, the battery is a traction battery of the motor vehicle, which provides electrical energy for driving the motor vehicle.

• 1 schematisch und ausschnittsweise eine Batterie mit einem Gehäuse und mit Batteriezellen, wobei die Batteriezellen anhand einer ersten Klettverbindung mit einem Gehäuseboden des Gehäuses und anhand einer zweiten Klettverbindung mit einem Gehäusedeckel des Gehäuses verbunden sind,
• 2a schematisch und ausschnittsweise die erste Klettverbindung, wobei zwischen deren Klettbändern ein thermisch leitendes Gel und/oder eine Wärmeleitpaste angeordnet ist, und
• 2b schematisch und ausschnittsweise die zweite Klettverbindung, wobei zwischen deren Klettbändern ein thermisch leitendes Gel und/oder eine Wärmeleitpaste angeordnet ist.

In the following, embodiments of the invention are explained in more detail with reference to a drawing. In the drawing:

• 1 schematically and in detail a battery with a housing and with battery cells, wherein the battery cells are connected to a housing base of the housing by means of a first Velcro connection and to a housing cover of the housing by means of a second Velcro connection,
• 2a schematically and in detail the first Velcro connection, with a thermally conductive gel and/or a thermally conductive paste arranged between the Velcro strips, and
• 2 B schematically and in detail the second Velcro connection, wherein a thermally conductive gel and/or a thermal paste is arranged between the Velcro strips.

Corresponding parts and sizes are always provided with the same reference symbols in all figures.

In the 1 a battery 2 is shown schematically. This comprises a battery housing 4 (housing 4), whereby only its housing base 6 (base 6) and its housing cover 8 are shown. The housing base 6 and the housing cover 8 are arranged opposite one another, whereby they are oriented parallel to one another.

A number of battery cells 10 are arranged in the battery housing 4 between the housing base 6 and the housing cover 8, of which only three are shown for the sake of better clarity. The battery cells 10 are arranged next to one another in a row direction R, which runs parallel to the housing base. The battery cells 10 form a so-called cell pack.

In particular, the battery 2 is designed according to a Cell2Pack or Cell2Car design, so that the battery cells 10 are inserted directly into the battery housing 4, i.e. are not combined into modules.

Each of the battery cells 10 is connected to the housing base 6 by means of a first Velcro connection 12 and to the housing cover 8 by means of a second Velcro connection 14. In other words, each of the battery cells 10 is joined to the housing base 6 by means of the first Velcro connection 12 and to the housing cover 8 by means of a second Velcro connection 14.

As in the 2a and 2 B As shown in more detail, the first Velcro connection 12 is formed by two Velcro units 16, each designed as a Velcro strip. These Velcro units 16 comprise a base body 18 glued to the battery cell 10 or to the housing base 6, on which a plurality of Velcro fastening elements 20 are arranged, which protrude from the base body 18. Accordingly, the second Velcro connection 14 is formed by two Velcro units 16, each designed as a Velcro strip. These comprise a base body 18 glued to the battery cell 10 or to the housing cover 8, on which a plurality of Velcro fastening elements 20 are arranged, which protrude from the base body 18.

The Velcro fastener elements 20 have according to the 2a and 2 B shown embodiment has a mushroom head shape. In other words, the Velcro units 16 are designed as mushroom head bands that complement each other.

According to alternatives not shown in more detail, the Velcro units 16 are designed in an otherwise analogous manner as a hook tape and a loop tape complementary thereto, as a mushroom head tape and a loop tape complementary thereto, or as a hook tape and a mushroom head tape complementary thereto.

When the battery 2 is assembled, a gap 22 is formed between the Velcro units 16 of the first Velcro connection 12, in particular between their base bodies 18 and/or between their Velcro elements 20. To improve heat conduction from the respective battery cell 10 to the housing base 6, a thermally conductive gel 24 is introduced into this gap 22. According to an alternative not shown in more detail, a colloid or, according to a further alternative, a thermally conductive paste is introduced into this gap 22. In particular, the gap 22 is filled with the colloid, with the gel 24 or with the thermally conductive paste.

In an analogous manner, in the assembled state of the battery 2, a (further) intermediate space 22 is formed between the Velcro units 16 of the second Velcro connection 14, in particular between their base bodies 18 and/or between their Velcro elements 20. To improve heat conduction from the respective battery cell 10 to the housing cover 8, thermally conductive gel 24 or, according to an alternative not shown, thermally conductive paste is introduced into this (further) intermediate space 22. In particular, the intermediate space 22 is filled with the gel 24 or with the thermally conductive paste.

In summary, a thermally conductive gel 24 and/or a thermally conductive paste is inserted between the Velcro units 16 of the first Velcro connection 12 and between the Velcro units 16 of the second Velcro connection 14. In the 2a and 2 B is Gel 24 is shown hatched for better visibility.

In particular, the thermal conductivity of the gel 18 and/or the thermal paste is greater than 4 W/(m · K), in particular greater than 7 W/(m · K). Preferably, the thermal conductivity of the gel is between 4 W/(m · K) and 20 W/(m · K), in particular between 7 W/(m · K) and 13 W/(m K). The gel 18 also has a viscosity that is greater than 150,000 mPa s and less than 5,000,000 mPa s.

The Velcro units 16, i.e. their base body 18 and their Velcro fastener elements 20, of the first Velcro connection 12 and the Velcro units 16 of the second Velcro connection 14 are each made of a polymer, such as polypropylene, polyamide, polyaramide, polyester and polyolefin. Alternatively, the Velcro units 16, i.e. their base body 18 and their Velcro fastener elements 20, are made of a metal such as aluminum or an alloy such as steel. If the Velcro units 16 are made of metal or an alloy, they are coated, for example, so that electrical conductivity is reduced.

Due to such an arrangement of the battery cells 10 and their Velcro connections 12, 14 with the housing 4, the battery 2 has a structure which is essentially comparable to a double-T beam or a sandwich sheet. The arrangement and orientation of the battery cells 10 and the Velcro connections thus increases the stability and rigidity of the battery 2, which increases safety in the event of a crash. A head tensile load for releasing the first and/or second Velcro connections is dimensioned to be greater than 5 MPa.

As particularly in the 1 As can be seen, the battery cells 10 are furthermore each reversibly connected to one another and in particular can be detached from one another without tools using a further, third Velcro connection 26. The battery cells 10 are preferably electrically insulated from one another using the third Velcro connection 26.

Optional is, as further in the 1 As can be seen, the housing base 6 and the housing cover 8 can be cooled. For this purpose, the housing base 6 and the housing cover 8 each have a cooling channel 28 through which a cooling medium can flow.

In a manner not shown in detail, an electrically powered motor vehicle has the battery 2 as a traction battery. The battery 2 therefore serves to provide electrical energy for an electric motor to drive the motor vehicle.

The invention is not limited to the embodiments described above. Rather, other variants of the invention can be derived from this by a person skilled in the art within the scope of the claims without departing from the subject matter of the invention. In particular, all individual features described in connection with the embodiments and/or in the claims can also be combined with one another in other ways without departing from the subject matter of the invention.

List of reference symbols

2

battery

4

Battery housing

6

Case back

8th

Housing cover

10

Battery cell

12

first velcro connection

14

second velcro connection

16

Velcro unit

18

Base body

20

Velcro fastening element

22

Space

24

gel

26

third velcro connection

28

Cooling channel

R

Row direction

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 2007/0224498 A1 [0006]
• WO 2020/192196 A1 [0007]

Claims (8)

Battery (2) for an electrically powered motor vehicle, comprising - a battery housing (4) with a housing base (6) and with a housing cover (8), and - a battery cell (10) arranged in the battery housing (4), - wherein the battery cell (10) is connected to the housing base (6) by means of a first Velcro connection (12) and/or to the housing cover (8) by means of a second Velcro connection (14), and - wherein a thermally conductive colloid (24), a thermally conductive gel (24), and/or a thermally conductive paste is introduced between Velcro units (16) of the first Velcro connection (12) and/or between Velcro units (16) of the second Velcro connection (14). Battery (2) after Claim 1 , characterized in that the thermal conductivity of the gel (24), the colloid (24), and/or the thermal paste is greater than 4 W/(m · K), in particular greater than 7 W/(m · K). Battery (2) after Claim 1 or 2 , characterized in that the viscosity of the gel (24) is between 150000 mPa·s and 5000000 mPa·s. Battery (2) according to one of the Claims 1 until 3 , characterized in that a head tensile load for opening the first Velcro connection (12) and/or the second Velcro connection (14) is greater than 5 MPa. Battery (2) according to claim one of the Claims 1 until 4 , characterized in that the Velcro units (16) of the first Velcro connection (12) and/or the Velcro units (16) of the second Velcro connection are each formed from a polymer. Battery (2) according to one of the Claims 1 until 4 , characterized in that the Velcro units (16) of the first Velcro connection (12) and/or the Velcro units (16) of the second Velcro connection are each made of metal or an alloy. Battery (2) according to one of the Claims 1 until 6 , characterized in that the housing base (6) and/or the housing cover (8) can be cooled. Electrically powered motor vehicle with a battery (2) according to one of the Claims 1 until 7 .

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