KR20240159459A - An Electrode Assembly Including An Anode With An Insulating Coating Layer And A Manufacturing Method Thereof - Google Patents

Abstract

The present invention relates to an electrode assembly including an anode having an insulating coating layer and a method for manufacturing the same, and more particularly, to an electrode assembly including an anode having an insulating coating layer, and a method for manufacturing the same, wherein the electrode assembly comprises: at least one first monocell; and a second monocell laminated on the uppermost part of the first monocell; wherein the second monocell is characterized in that it has an insulating coating layer.

Description

{An Electrode Assembly Including An Anode With An Insulating Coating Layer And A Manufacturing Method Thereof}

The present invention relates to an electrode assembly including an anode having an insulating coating layer and a method for manufacturing the same, and more particularly, to an electrode assembly including an anode having an insulating coating layer capable of increasing energy density while enabling a stable manufacturing process, and a method for manufacturing the same.

Recently, due to the development of alternative energy sources to address air pollution and energy depletion caused by the use of fossil fuels, the demand for secondary batteries that can store the generated electric energy has increased. Secondary batteries that can be recharged and discharged are closely used in everyday life, such as in mobile devices, electric vehicles, and hybrid electric vehicles.

Secondary batteries, which are used as energy sources for various electronic devices that are indispensable in modern society, are seeing an increase in capacity requirements due to the increase in the use and complexity of mobile devices and the development of electric vehicles. In order to meet user demands, a large number of battery cells are placed in small devices, but in automobiles, battery modules that electrically connect a large number of battery cells or battery packs equipped with a large number of such battery modules are used.

Meanwhile, as shown in Fig. 1, which is a cross-sectional view of an electrode stack according to the prior art, an electrode assembly housed in a cell case is generally configured by sequentially stacking a plurality of monocells (M) arranged in the order of a separator (30), a cathode (20), a separator (30), and an anode (10), and one half-cell (H) arranged in the order of a separator (30), a cathode (20), and a separator (30).

However, the half-cell located at the top of the electrode assembly is composed of a separator, cathode, and separator, and is thinner than the mono-cell, making it difficult to transport or stack, which is likely to lead to reduced efficiency in the production process or defective products.

In addition, after stacking multiple monocells and one half-cell, a process must be followed to wrap the electrode assembly with a separate insulating material, such as a separator, to ensure insulation with the cell case.

Korean Patent Publication No. 2015-0100017

In order to solve the above problems, the present invention aims to provide an electrode assembly including an anode having an insulating coating layer capable of a stable production process and a method for manufacturing the same.

In addition, the present invention aims to provide an electrode assembly including an anode having an insulating coating layer capable of increasing production efficiency by reducing unit production processes, and a method for manufacturing the same.

In order to achieve the above-described purpose, an electrode assembly according to the present invention comprises: at least one first monocell; and a second monocell laminated on the uppermost part of the first monocell; wherein the second monocell is characterized in that it has an insulating coating layer.

In addition, in the electrode assembly according to the present invention, the insulating coating layer is characterized by being made of at least one of polyethylene terephthalate (PET), polypropylene (PP), and ceramic.

In addition, in the electrode assembly according to the present invention, the insulating coating layer is characterized by being made of ceramic.

In addition, in the electrode assembly according to the present invention, the second monocell is characterized in that it is laminated in the order of a second separator, a second cathode, a second separator, and a second anode from below, and the insulating coating layer is provided on the second anode.

In addition, in the electrode assembly according to the present invention, the second positive electrode is characterized in that the second positive electrode active material, the second positive electrode current collector, and the insulating coating layer are laminated in this order from below.

In addition, in the electrode assembly according to the present invention, the thickness of the second monocell is characterized by being in the range of 150 to 250 μm.

In addition, in the electrode assembly according to the present invention, the thickness of the insulating coating layer is characterized by being in the range of 10 to 20 μm.

In addition, in the electrode assembly according to the present invention, the first monocell is laminated in the order of a first separator, a first cathode, a first separator, and a first cathode from below, and at least one of the first cathode and the second cathode for lithium ion storage is characterized in that it includes silicon.

In addition, in the electrode assembly according to the present invention, the silicon is characterized in that it is 95 wt% or more based on the negative electrode active material.

In addition, in the electrode assembly according to the present invention, the thickness of the first monocell is characterized by being in the range of 150 to 250 μm.

In addition, in the electrode assembly according to the present invention, the thickness of the first monocell is characterized by being in the range of 150 to 200 μm.

Additionally, the present invention may be a battery cell including the electrode assembly described above.

In addition, a method for manufacturing an electrode assembly according to the present invention includes a first step of preparing at least one first mono-cell and a second mono-cell; and a second step of sequentially stacking at least one first mono-cell and one second mono-cell from below, wherein the first mono-cell is stacked in the order of a first separator, a first cathode, a first separator, and a first anode from below, and the second mono-cell is stacked in the order of a second separator, a second cathode, a second separator, and a second anode from below, and the second anode is characterized in that it comprises a second cathode current collector, a second cathode active material on a lower surface of the second cathode current collector, and an insulating coating layer on an upper surface of the second cathode current collector.

In addition, in the electrode assembly manufacturing method according to the present invention, the insulating coating layer is characterized in that it is ceramic.

In addition, in the electrode assembly manufacturing method according to the present invention, at least one of the first cathode and the second cathode is characterized in that it includes silicon.

As described above, an insulating coating layer is positioned on the uppermost part of the second cathode constituting the second monocell of the electrode assembly according to the present invention, which has the advantage of being able to maintain an insulating state between the electrode assembly and the battery case without a separate separator covering the entire electrode assembly, thereby contributing to simplification of the production process and reduction of manufacturing costs.

In addition, when the insulating coating layer on the uppermost part of the second anode constituting the second monocell of the electrode assembly according to the present invention is made of ceramic, the phenomenon of the second anode or the second monocell being bent or sagging can be minimized, so there is an advantage in that the transport or stacking of the second anode or the second monocell is very easy.

In addition, since the negative electrode active material of the electrode assembly according to the present invention is centered on a silicon-based negative electrode active material, there is an advantage in that the storage capacity of lithium ions can be increased, thereby improving the energy density.

Figure 1 is a cross-sectional view of an electrode stack according to conventional technology.
Figure 2 is an exploded cross-sectional view of an electrode assembly according to a preferred embodiment of the present invention.
Figure 3 is an enlarged cross-sectional view of a first monocell according to a preferred embodiment of the present invention.
Figure 4 is an enlarged cross-sectional view of a second monocell according to a preferred embodiment of the present invention.

Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those with ordinary skill in the art can easily implement the present invention. However, when describing the operating principles of preferred embodiments of the present invention in detail, if it is determined that a specific description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

Also, the same drawing symbols are used for parts that have similar functions and actions throughout the drawings. Throughout the specification, when a part is said to be connected to another part, this includes not only cases where it is directly connected, but also cases where it is indirectly connected with other elements in between. Also, including a certain component does not mean excluding other components unless specifically stated otherwise, but rather means that other components can be included.

Hereinafter, an electrode assembly including an anode having an insulating coating layer according to the present invention and a manufacturing method thereof will be described with reference to the attached drawings.

FIG. 2 is an exploded cross-sectional view of an electrode assembly according to a preferred embodiment of the present invention, FIG. 3 is an enlarged cross-sectional view of a first monocell according to a preferred embodiment of the present invention, and FIG. 4 is an enlarged cross-sectional view of a second monocell according to a preferred embodiment of the present invention.

Referring to FIGS. 2 to 4, the electrode assembly according to the present invention is configured to include one or more first monocells (100) and one second monocell (200), wherein the first monocell (100) is positioned below and the second monocell (200) is positioned at the upper outermost portion.

First, the first monocell (100) has a configuration substantially identical to that of a generally known monocell consisting of two separators, one cathode, and one anode. That is, the first separator (110), the first cathode (120), the first separator (110), and the first anode (130) are stacked in that order from the bottom.

The first separator (110) is positioned on the lower surface of the first negative electrode (120) and between the upper surface of the first negative electrode (120) and the lower surface of the first positive electrode (130), respectively, to prevent short circuiting between the first negative electrode (120) and the first positive electrode (130) and to allow only the movement of lithium ions.

The material of the first separation membrane (110) is preferably one selected from among polyethylene, polypropylene, polyethylene/polypropylene double layer, polyethylene/polypropylene/polyethylene triple layer, polypropylene/polyethylene/polypropylene triple layer, and organic fiber filter paper, but is not limited thereto.

The first negative electrode (120) is configured to include a first negative electrode current collector (121), and a first negative electrode active material (122) applied to the lower and upper surfaces of the first negative electrode current collector (121), respectively.

The first negative electrode collector (121) is generally made with a thickness of 3 to 500 ㎛. The first negative electrode collector (121) is not particularly limited as long as it is conductive and does not cause a chemical change in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, charcoal, silver, etc., aluminum-cadmium alloy, etc. can be used.

In addition, the bonding strength of the negative electrode active material can be strengthened by forming fine roughness on the surface, and it can be used in various forms such as a film, sheet, foil, net, porous body, foam, and non-woven fabric.

The first negative electrode active material (122) for lithium ion storage may include graphite, silicon, and/or lithium metal, or the negative electrode active material may be mostly composed of silicon. For example, it is preferable that silicon is 95 wt% or more based on the negative electrode active material, and more preferably 99 wt%.

The silicon-based negative electrode active material may be at least one of Si, SiO, SiO _2, and a nano silicon composite, and the nano silicon composite may be any one of a silicon alloy, and the metal element contained in the silicon alloy may be at least one of Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, Se, Te, and Po.

Of course, a conductive material and a binder may be additionally mixed into the first negative electrode active material (122) and coated on the first negative electrode current collector (121).

The conductive agent is a component for further improving the conductivity of the negative electrode active material, and may be used in a certain ratio, including carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers or metal fibers; metal powders such as fluorinated carbon, aluminum, and nickel powder; conductive whiskies such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives.

The binder is a component that assists in the binding of the negative electrode active material and the conductive material and the binding to the current collector, and may include at least one selected from the group consisting of styrene butadiene rubber (SBR), acrylonitrile butadiene rubber, acrylic rubber, butyl rubber, fluoro rubber, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl alcohol (PVA), polyacrylic acid (PAA), polyethylene glycol (PEG), polyacrylonitrile (PAN), and polyacryl amide (PAM).

In this way, when a silicon-based negative electrode active material is used for lithium ion storage, more lithium ions can be stored per unit area than the graphite-based negative electrode active material used in the past, which improves the energy density and can contribute to reducing the overall volume of the electrode assembly.

The first positive electrode (130) is configured to include a first positive electrode current collector (131) and a first positive electrode active material (132) applied to the upper and lower surfaces of the first positive electrode current collector (131), respectively.

The first cathode current collector (131) can generally have a thickness of 3 to 500 ㎛. There is no particular limitation as long as it has high conductivity without causing chemical changes in the battery, and for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. can be used. In addition, in order to increase the adhesive strength of the cathode active material, the surface can be formed with fine unevenness, or various shapes such as a film, sheet, foil, net, porous body, foam, or non-woven fabric are possible.

The first cathode active material (132) is a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with a transition metal of a higher order; lithium manganese oxides such as Li _1+x Mn _2-x O ₄ (wherein, x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , LiMnO ₂ ; lithium copper oxide (Li ₂ CuO ₂ ); vanadium oxides such as LiV ₃ O ₈ , V ₂ O ₅ , Cu ₂ V ₂ O ₇ ; Ni-site type lithium nickel oxide expressed by the chemical formula LiNi _1-x M _x O ₂ (wherein, M = Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x = 0.01 to 0.3); Lithium manganese composite oxides represented by the chemical formula LiMn _2-x M _x O ₂ (wherein, M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1) or Li ₂ Mn ₃ MO ₈ (wherein, M = Fe, Co, Ni, Cu or Zn); LiMn ₂ O ₄ in which a part of the Li in the chemical formula is replaced with an alkaline earth metal ion; disulfide compounds; Fe ₂ (MoO ₄ ) ₃ , LiNi _x Mn _2-x O ₄ (0.01≤x≤0.6), etc. can be used.

Meanwhile, a conductive material and a binder may be mixed into the first cathode active material (132), and a filler may be further added as needed.

The conductive agent is typically added in an amount of 1 to 50 wt% based on the total weight of the mixture including the first cathode active material (132). The conductive agent is not particularly limited as long as it has conductivity without causing a chemical change in the battery, and for example, graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black; conductive fibers such as carbon fiber or metal fiber; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskey such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives, etc. can be used.

The binder is a component that assists in the bonding of the first cathode active material (132) and the conductive material, etc., and the bonding to the current collector, and is typically added in an amount of 1 to 50 wt% based on the total weight of the mixture including the first cathode active material (132). Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluororubber, various copolymers, etc.

The thickness of the first monocell (100) including the aforementioned configurations may be 400 ㎛ or less, preferably 150 to 250 ㎛, and more preferably 150 to 200 ㎛.

The second monocell (200) has a similar structure to the first monocell (100), and is laminated in the following order from the bottom: the second separator (210), the second cathode (220), the second separator (210), and the second anode (230).

Here, the second separator (210) may be identical to the first separator (110) of the first monocell (100) described above, and the second cathode (220) may have the same configuration as the first cathode (120) described above, so redundant descriptions will be omitted.

The second positive electrode (230) is configured to include a second positive electrode collector (231), a second positive electrode active material (232) applied to the lower surface of the second positive electrode collector (231), and an insulating coating layer (233) positioned on the upper surface of the second positive electrode collector (231).

The second cathode current collector (231) and the second cathode active material (232) may each have the same configuration as the first cathode current collector (131) and the first cathode active material (132) described above.

The insulating coating layer (233) located on the upper surface of the second cathode current collector (231), that is, the outermost upper portion of the electrode assembly, may be made of an insulating material.

As the material of the insulating coating layer (233), it is preferable to select at least one of polyethylene terephthalate (PET), polypropylene (PP), and ceramic, and polypropylene (PP) or ceramic is more preferable.

In particular, ceramic is most preferable as a material for the insulating coating layer (233), because the mechanical strength of the second anode (230) is improved due to the formation of the ceramic coating layer, and furthermore, it can maintain a certain degree of stiffness, making it easy to transport or stack the second anode (230).

Here, the thickness of the insulating coating layer (233) is preferably in the range of 10 to 20 μm.

When the surface exposed to the outside and located at the uppermost outer surface of the electrode assembly is formed with an insulating coating layer (233) in this way, the insulation state between the electrode assembly and the battery case can be maintained without a separate separator covering the entire electrode assembly.

In addition, while a half-cell composed of a separator, a cathode, and a separator is positioned at the top of a conventional electrode assembly, in the present invention, a second cathode having a second cathode active material applied to the second cathode current collector and an insulating coating layer formed on the upper surface is additionally provided on the upper surface of the separator. Accordingly, the thickness is increased compared to a conventional half-cell, and this has the advantage of allowing stabilization of processes such as transport and lamination of the half-cell.

Meanwhile, the thickness of the second monocell (200) including the aforementioned configurations may be 400 ㎛ or less, preferably 150 to 250 ㎛, and more preferably in the range of 150 ㎛ or more and less than 200 ㎛.

The method for manufacturing an electrode assembly according to the present invention having the above-described configuration comprises a first step of preparing one or more first mono cells (100) and second mono cells (200), and a second step of sequentially stacking one or more first mono cells (100) and second mono cells (200) from below.

As described above, the first monocell (100) has a structure in which the first separator (110), the first cathode (120), the first separator (110), and the first anode (130) are laminated in that order from the bottom, and the second monocell (200) has a structure in which the second separator (210), the second cathode (220), the second separator (210), and the second anode (230) are laminated in that order from the bottom.

The detailed configurations of the first separator (110), the first cathode (120), the first separator (110) and the first anode (130) constituting the first monocell (100), and the second separator (210), the second cathode (220), the second separator (210) and the second anode (230) constituting the second monocell (200) are as described above, so redundant descriptions will be omitted.

The present invention may be a pouch-type secondary battery storing the aforementioned electrode assembly, and may also be a battery module or battery pack including the aforementioned secondary battery.

Anyone with ordinary skill in the art will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

100: 1st Monocell
110: 1st separation membrane
120: First cathode
121: First negative electrode collector 122: First negative electrode active material
130: First Anode
131: First cathode current collector 132: First cathode active material
200: 2nd Monocell
210: Second Separator
220: Second cathode
221: Second negative electrode collector 222: Second negative electrode active material
230: Second Anode
231: Second positive electrode collector 232: Second positive electrode active material
233: Insulating coating layer

Claims (15)

one or more first monocells; and
A second monocell stacked on the top of the first monocell; including:
An electrode assembly characterized in that the second monocell is provided with an insulating coating layer. In the first paragraph,
An electrode assembly characterized in that the insulating coating layer is made of at least one of polyethylene terephthalate (PET), polypropylene (PP), and ceramic. In the second paragraph,
An electrode assembly characterized in that the insulating coating layer is made of ceramic. In the second paragraph,
An electrode assembly characterized in that the second monocell is laminated in the order of a second separator, a second cathode, a second separator, and a second anode from below, and the insulating coating layer is provided on the second anode. In paragraph 4,
An electrode assembly characterized in that the second positive electrode is laminated in the following order: a second positive electrode active material, a second positive electrode current collector, and an insulating coating layer from below. In the third paragraph,
An electrode assembly, characterized in that the thickness of the second monocell is in the range of 150 to 250 μm. In Article 6,
An electrode assembly characterized in that the thickness of the insulating coating layer is in the range of 10 to 20 μm. In paragraph 4,
An electrode assembly characterized in that the first monocell is laminated in the order of a first separator, a first cathode, a first separator, and a first cathode from below, and at least one of the first cathode and the second cathode for lithium ion storage includes silicon. In Article 8,
An electrode assembly characterized in that the silicon is 95 wt% or more based on the negative electrode active material. In Article 8,
An electrode assembly, characterized in that the thickness of the first monocell is in the range of 150 to 250 μm. In Article 10,
An electrode assembly, characterized in that the thickness of the first monocell is in the range of 150 to 200 μm. A battery cell comprising an electrode assembly according to any one of claims 1 to 11. A first step of preparing one or more first monocells and second monocells; and
A second step of sequentially stacking one or more first monocells and one second monocell from below;
The above first monocell is laminated in the order of the first separator, the first cathode, the first separator, and the first anode from below,
The above second monocell is laminated in the order of the second separator, the second cathode, the second separator, and the second anode from below.
A method for manufacturing an electrode assembly, characterized in that the second positive electrode is composed of a second positive electrode collector, a second positive electrode active material on the lower surface of the second positive electrode collector, and an insulating coating layer on the upper surface of the second positive electrode collector. In Article 13,
A method for manufacturing an electrode assembly, characterized in that the insulating coating layer is made of ceramic. In Article 14,
A method for manufacturing an electrode assembly, characterized in that at least one of the first cathode and the second cathode comprises silicon.

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