KR102070907B1 - Battery Cell Comprising Non-coating Portion Accommodating Gas Generated During Charge and Discharge - Google Patents

Abstract

The present invention is a battery cell in which an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode is embedded in a battery case together with an electrolyte, wherein the battery case is a laminate sheet comprising a resin layer and a metal layer. Consists of a pouch-shaped case, the positive electrode and the negative electrode are coated with an electrode active material on the surface of the current collector, respectively, and a gas receiving portion for receiving gas generated during charging and discharging of the battery cell to prevent expansion of the battery case, positive and negative electrodes. It provides a battery cell, characterized in that formed in at least one of the.

Description

Battery Cell Comprising Non-coating Portion Accommodating Gas Generated During Charge and Discharge}

The present invention relates to a battery cell characterized in that the gas receiving portion for preventing the expansion of the battery case by receiving the gas generated during charging and discharging of the battery cell is formed on at least one of the positive electrode and the negative electrode.

Due to the rapid increase in the use of fossil fuels, the demand for the use of alternative energy or clean energy is increasing, and as a part, the most actively researched field is the field of electricity generation and electricity storage using electrochemistry.

Currently, a representative example of an electrochemical device using such electrochemical energy is a secondary battery, and its use area is gradually expanding.

Secondary batteries are classified into cylindrical batteries and rectangular batteries in which the electrode assembly is embedded in a cylindrical or square metal can, and pouch-shaped batteries in which the electrode assembly is embedded in a pouch-shaped case of an aluminum laminate sheet, depending on the shape of the battery case. .

The electrode assembly embedded in the battery case is a power generator capable of charging and discharging consisting of a stacked structure of anode / separator / cathode, and a jelly-roll type wound through a separator between a long sheet-type anode and a cathode coated with an active material, and a predetermined It is classified into a stack type in which a plurality of anodes and cathodes of a size are sequentially stacked with a separator interposed therebetween.

As an electrode assembly having an advanced structure, which is a mixed form of a jelly-roll type and a stack type, a full cell or a cathode (cathode) / separator / cathode (anode) / separator / A stack / folding electrode assembly having a structure in which a bicell having an anode (cathode) structure is folded using a long continuous membrane film has been developed.

In addition, in order to improve the processability of the existing stacked electrode assembly and to meet the demands of various types of secondary batteries, the lamination / stacked electrode having a structure in which unit cells in which electrodes and separators are alternately laminated and laminated are stacked. Assembly was also developed.

In particular, in the case of a pouch-type battery in which the electrode assembly is embedded in a pouch-shaped case together with an electrolyte, the voltage rises during charging and discharging of the battery, and the electrolyte inside the battery decomposes due to overheating, thereby generating combustible gas. The swelling phenomenon of swelling occurs.

In order to solve this problem, a technology for chemically preventing overcharge by using a composition such as a non-aqueous electrolyte and a compound that decomposes when overcharge is used as an electrolyte, and a circuit for blocking electrical flow when overheating, overcurrent, or overvoltage occurs, or Various techniques have been developed to prevent an overcharge by electrically causing the fuse to blow due to overheating.

However, in the case of such chemical overcharge prevention technology, there is a disadvantage that performance is remarkably deteriorated compared to the electrolyte currently used, and in the case of electrical overcharge prevention technology, an independent circuit must be formed and attached to the battery, so the manufacturing process is complicated. There are problems such as losing and rising costs.

Therefore, there is a high need for a technology that can overcome the above problems.

The present invention aims to solve the problems of the prior art as described above and the technical problems requested from the past.

The inventors of the present application have repeatedly conducted various experiments and in-depth studies, and the battery cell is formed in at least one of the positive electrode and the negative electrode to receive gas generated during charging and discharging of the battery cell to prevent expansion of the battery case. It was developed, and when using such a battery cell, it was confirmed that a desired effect can be achieved, and the present invention has been completed.

Accordingly, the present invention is a battery cell in which an electrode assembly including an anode, a cathode, and a separator interposed between the anode and the cathode is embedded in a battery case together with an electrolyte, wherein the battery case includes a resin layer and a metal layer. It consists of a pouch-shaped case of a laminate sheet, and the positive electrode and the negative electrode are each coated with an electrode active material on the surface of the current collector, and a gas receiving portion that receives gas generated during charging and discharging of the battery cell to prevent expansion of the battery case. It consists of a structure formed on at least one of the anode and the cathode.

That is, according to the present invention, the battery cell is to prevent the expansion of the battery case according to the swelling phenomenon without the need for separate electrical and chemical methods are bars, above which is formed in the gas receiving portion electrode for receiving the gas that occur during the charge and discharge Can be.

The electrode assembly may include a plurality of bicells and / or full cells described above in consideration of the required capacity and output of the battery, and may be stacked, or stacked / folded, or lamination / stacked. It may be made of a structure.

In this structure, the positive electrode terminal and the negative electrode terminal may be formed at opposite ends of the electrode assembly, respectively, and may be formed together at one end of the electrode assembly while facing the same direction.

In one specific example, the gas receiving portion is formed in the form of an active material uncoated portion that is not coated with an electrode active material, and a structure in which an active material coating portion having an electrode active material coated on a current collector is positioned around the active material uncoated portion It can be made of. Therefore, since the uncoated portion of the active material remains as a surplus site in the electrode assembly, it is possible to properly accommodate the gas generated during charging and discharging of the battery cell.

The gas accommodating part is not particularly limited as long as the gas generated inside the battery cell can be effectively received without affecting the required capacity and output of the battery, but in one example, it crosses the center of the electrode assembly in a plane. It can be formed in a stripping shape. In this structure, the gas receiving portion may be formed in a structure that extends linearly by performing an end (a) at which the electrode terminal is located from an end (b) opposite the end (a) at which the electrode terminal is located.

Further, at least a part of the current collector in the gas receiving portion may be formed in a structure in which cutouts are removed so as to secure an additional space for receiving gas and to implement various shapes of the electrodes. In such a structure, 30% to 80% of the current collector may be cut off from the gas receiving portion. If the area to be cut out outside the above range is less than 30%, it may be difficult to achieve an effect of accommodating more gas generated inside the battery, and when it exceeds 80%, excessive current may be applied to the part where the current collector is not removed. It is not preferable because it may cause problems in battery stability, such as overheating caused by current flow.

In some cases, the gas receiving portion extends linearly from the end (b) opposite the end (a) where the electrode terminal is located toward the end (a) where the electrode terminal is located, adjacent to the end (a). A current collector to which the electrode active material is not applied may be positioned at a site, and at least a portion of the current collector may be cut off from the gas receiving part at a site adjacent to the end portion b. Furthermore, in order to further secure an additional space to accommodate gas and to form various shapes of the electrode assembly, the current collector may be formed in a structure in which the separation membrane is cut out in correspondence with the cut-off portion.

In another specific example, the gas receiving portion may be formed in various shapes on a central portion of the electrode assembly in a planar shape, and preferably may be formed in a polygonal or circular or oval shape. The shape and position of the gas receiving portion may be determined in consideration of the main generating portion of gas generated during operation of the battery cell and the maximum stretching portion of the pouch-shaped case due to such gas generation (here, stretching means that the case is stretched) box).

In one example, in the case of a plate-shaped pouch-shaped case, when gas is generated, the case is most inflated in a central portion of the case, so that the gas receiving portion is located in the central portion of the electrode assembly to receive this gas, thereby It is desirable to prevent expansion as much as possible. Further, at least a part of the current collector in the gas receiving portion may be formed in a structure in which cutouts are removed so as to secure an additional space for receiving gas and to implement various shapes of the electrodes. At this time, 50% to 100% of the current collector may be cut off from the gas receiving portion. Furthermore, the separator may be formed in a structure in which the separator is cut out in correspondence to the part where the current collector is cut out.

In another specific example of the battery cell according to the present invention, the gas receiving portion is formed on each of the positive electrode and the negative electrode, and the position of the gas receiving portion formed on the positive electrode corresponds to the structure of the gas receiving portion formed on the negative electrode. It can be formed of. Such a structure makes it possible to more easily form the gas receiving portion in the electrode assembly, thereby simplifying the manufacturing process and providing an effect of providing a relatively large volume of gas receiving portion. However, it goes without saying that the position of the gas receiving portion formed on the anode may be inconsistent with the position of the gas receiving portion formed on the cathode.

Other components included in the battery cell of the present invention will be described below.

The positive electrode is prepared by applying a mixture of a positive electrode active material, a conductive material, and a binder on a current collector for a positive electrode, followed by drying and pressing, and if necessary, a filler is further added to the mixture.

The positive electrode current collector is generally made to a thickness of 3 to 500 μm. The current collector for the positive electrode is not particularly limited as long as it has high conductivity without causing a chemical change in the battery. For example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel Surfaces made of carbon, nickel, titanium, silver, etc. may be used on the surface of the steel. The current collector may also increase the adhesion of the positive electrode active material by forming fine irregularities on its surface, and various forms such as a film, sheet, foil, net, porous body, foam, and nonwoven fabric are possible.

The positive electrode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ) or lithium nickel oxide (LiNiO ₂ ) or a compound substituted with one or more transition metals; Lithium manganese oxides such as the formula Li _{1 + x} Mn _2-x O ₄ (where x = 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , and LiMnO ₂ ; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ and Cu ₂ V ₂ O ₇ ; A Ni-site type lithium nickel oxide represented by the formula LiNi _1-x M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3); Formula LiMn _2-x M _x O ₂ (where M = Co, Ni, Fe, Cr, Zn or Ta, x = 0.01 to 0.1) or Li ₂ Mn ₃ MO ₈ (where M = Fe, Co, Lithium manganese composite oxide represented by Ni, Cu or Zn); A lithium manganese composite oxide having a spinel structure represented by LiNi _x Mn _2-x O ₄ (where 0≤x <1); LiMn ₂ O _{4 in} which part of Li in the formula is substituted with alkaline earth metal ions; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ and the like, but are not limited to these.

The conductive material is usually added in 1 to 30% by weight based on the total weight of the mixture containing the positive electrode active material. The conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the battery. 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, and summer black; Conductive fibers such as carbon fibers and metal fibers; Metal powders such as carbon fluoride powder, aluminum powder, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives may be used.

The binder is a component that assists in bonding the active material and the conductive material and the like to the current collector, and is usually added at 1 to 30% by weight based on the total weight of the mixture containing the positive electrode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropyl cellulose, recycled cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated EPDM, styrene styrene rubber, fluorine rubber, and various copolymers.

The filler is optionally used as a component that inhibits the expansion of the positive electrode, and is not particularly limited as long as it is a fibrous material without causing chemical changes in the battery, and includes, for example, an olefinic polymer such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

The negative electrode is prepared by applying, drying, and pressing the negative electrode active material on the negative electrode current collector, and optionally, a conductive material, a binder, a filler, and the like, as described above, may be further included.

The current collector for the negative electrode is generally made of a thickness of 3 ~ 500 ㎛. The current collector for the negative electrode is not particularly limited as long as it has conductivity without causing a chemical change in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel Surface-treated with carbon, nickel, titanium, silver, or the like, aluminum-cadmium alloy, or the like may be used. In addition, like the positive electrode current collector, it is also possible to form a fine unevenness on the surface to enhance the bonding force of the negative electrode active material, and may be used in various forms such as films, sheets, foils, nets, porous bodies, foams, and nonwoven fabrics.

The negative active material includes, for example, carbon such as non-graphitized carbon and graphite-based carbon; Li _x Fe ₂ O ₃ (0≤x≤1), Li _x WO ₂ (0≤x≤1), Sn _x Me _1-x Me ' _y O _z (Me: Mn, Fe, Pb, Ge; Me' : Al, B, P, Si, group 1, group 2, group 3 elements of the periodic table, halogen; metal composite oxides such as 0 <x≤1;1≤y≤3;1≤z≤8); Lithium metal; Lithium alloys; Silicon-based alloys; Tin-based alloys; SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , GeO, GeO ₂ , Bi ₂ O ₃ , Bi ₂ O ₄ , and Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni based materials and the like can be used.

The separator is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 μm, and the thickness is generally 5 to 300 μm. Examples of the separator include olefin-based polymers such as polypropylene, which are chemically resistant and hydrophobic; Sheets or non-woven fabrics made of glass fiber or polyethylene are used. When a solid electrolyte such as a polymer is used as the electrolyte, the solid electrolyte may also serve as a separator.

The electrolyte solution accommodated in the battery case together with the electrode assembly may be a non-aqueous electrolyte solution containing a lithium salt composed of a non-aqueous electrolyte solution and a lithium salt, and the non-aqueous electrolyte solution includes a non-aqueous organic solvent, an organic solid electrolyte, and an inorganic solid electrolyte. Used but not limited to these.

Examples of the non-aqueous organic solvent include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, and gamma. -Butyl lactone, 1,2-dimethoxy ethane, tetrahydroxy franc, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxorun, formamide, dimethylformamide, dioxol , Acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxy methane, dioxon derivative, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbohydrate Aprotic organic solvents such as nate derivatives, tetrahydrofuran derivatives, ethers, methyl pyropionate and ethyl propionate can be used.

Examples of the organic solid electrolyte include polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, poly agitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, A polymerization agent or the like containing an ionic dissociating group may be used.

Examples of the inorganic solid electrolyte include Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO ₄ -LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Li ₄ nitrides such as SiO ₄ -LiI-LiOH, Li ₃ PO ₄ -Li ₂ S-SiS ₂ , halides, sulfates, and the like can be used.

The lithium salt is a material soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO ₄ , LiBF ₄ , LiB ₁₀ Cl ₁₀ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF _{6, LiSbF 6, LiAlCl 4,} CH 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide.

In addition, the electrolyte is for the purpose of improving charge and discharge characteristics, flame retardancy, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme (glyme), hexaphosphate triamide, Nitrobenzene derivatives, sulfur, quinone imine dye, N-substituted oxazolidinone, N, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxy ethanol, aluminum trichloride, etc. may be added. have. In some cases, in order to impart non-flammability, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further included, or carbon dioxide gas may be further included to improve high temperature storage characteristics, and FEC (Fluoro-Ethylene) Carbonate), PRS (Propene sultone), etc. may be further included.

For example, lithium salts such as LiPF ₆ , LiClO ₄ , LiBF ₄ , and LiN (SO ₂ CF ₃ ) ₂ are cyclic carbonates of EC or PC, which are highly dielectric solvents, and linear carbonates of DEC, DMC, or EMC, which are low-viscosity solvents. It can be added to a mixed solvent of to prepare an electrolytic solution.

The present invention also provides a battery cell in which the electrode assembly is embedded in a battery case together with an electrolyte.

In one specific example, the battery case is a pouch-shaped case, and the positive electrode terminal and the negative electrode terminal may have a structure that is directly connected to respective terminal connection portions of a protective circuit member mounted on the outside of the pouch-shaped case. In particular, the pouch-type battery case may be made of a laminate sheet including a metal layer and a resin layer, and in detail, may be made of an aluminum laminate sheet in which the metal layer is Al.

The present invention also provides a device using a battery pack including the battery cell as a power source.

Specific examples of the device include: a mobile device, a wearable device, and a power tool moving under power by an omnidirectional motor; Electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs); Electric two-wheeled vehicles including electric bicycles (E-bikes) and electric scooters (E-scooters); Electric golf carts; It may be a power storage device (Energy Storage System).

The manufacturing method of the device is known in the art, and thus description is omitted here.

As described above, it was confirmed that the battery cell according to the present invention can prevent expansion of the battery case by receiving gas generated during charging and discharging of the battery cell.

1 is an exploded view of an electrode assembly according to the prior art;
2 is a schematic view of an anode according to an embodiment of the present invention;
3 is a schematic view of an anode according to another embodiment of the present invention;
4 is a schematic view of an electrode assembly according to another embodiment of the present invention;
5 is a schematic view of an electrode assembly according to another embodiment of the present invention;

Hereinafter, with reference to the drawings according to an embodiment of the present invention, it is for easier understanding of the present invention, and the scope of the present invention is not limited thereto. For reference, for simplicity and ease of understanding of the drawings, only some components of the electrode assembly are shown in the drawings. For example, in FIG. 1, an electrode assembly has been described by expressing only one bicell among a plurality of heterogeneous bicells constituting the electrode assembly.

1 is an exploded view of an electrode assembly 100 according to the prior art.

Referring to FIG. 1, the electrode assembly 100 includes a bicell structure in which a cathode 110 / a separator 140 / a cathode 120 / a separator 150 / a cathode 130 are sequentially stacked. The negative electrodes 110 and 130 include negative electrode active material coating parts 112 and 132 on both sides of the plate-shaped current collector, and negative electrode tabs 111 and 131 without active material coated on one end of the current collector are formed. Similarly, the positive electrode 120 includes a positive electrode active material coating unit 122 on both sides of a plate-shaped current collector, and a positive electrode tab 121 on which an active material is not coated is formed on one end of the current collector. In addition, the positive electrode tab 121 and the negative electrode tabs 111 and 131 face each other in the same direction and are formed at one end of the electrode assembly 100.

2 is a schematic diagram of an anode 200 according to an embodiment of the present invention.

Referring to FIG. 2, the positive electrode 200 includes a positive electrode active material coating part 212 on both sides of a plate-shaped current collector, and a positive electrode tab 211 without an active material coated on one end of the current collector is formed. The gas accommodating part 220 is formed in the form of an uncoated active material that is not coated with a positive electrode active material. Around the active material uncoated portion, a positive electrode active material coating portion 212 on which an electrode active material is coated on a current collector is located. The gas receiving portion 220 is formed in a strip shape across the center of the electrode assembly in a planar shape, and an electrode terminal is positioned from an end (b) opposite the end (a) where the anode tab (211) is located. It extends linearly toward (a).

In this way, the structure of the gas receiving portion formed in the form of an uncoated active material without an electrode active material coated may be applied to the negative electrode (not shown).

3 is a schematic diagram of an anode 300 according to another embodiment of the present invention.

Referring to FIG. 3, the positive electrode 300 includes a positive electrode active material coating part 312 on both surfaces of a plate-shaped current collector, and a positive electrode tab 311 without an active material coated on one end of the current collector is formed. The gas accommodating part 320 is formed in the form of an uncoated active material that is not coated with a positive electrode active material. Around the positive electrode active material uncoated portion, a positive electrode active material coating portion 312 having an electrode active material coated thereon is positioned. The gas receiving portion 320 is formed in a strip shape across the center of the electrode assembly in a planar shape, and an electrode terminal is positioned from an end (b) opposite to an end (a) where the anode tab (311) is located. It extends linearly toward (a). In this structure, at least a portion 321 of the current collector in the gas receiving portion 320 is cut off.

As described above, a structure in which at least a part of the current collector is cut off from the structure of the gas receiving portion formed in the form of an uncoated active material without an electrode active material coated may be applied to the negative electrode (not shown).

4 is a schematic diagram of an electrode assembly 400 according to an embodiment of the present invention.

Referring to FIG. 4, the electrode assembly 400 has the first cathode 401 / the first separator 430 / the anode 440 / the second separator / the second cathode as shown in FIG. 1 from the front of the drawing. It includes a bi-cell structure stacked in the rear direction (the second separator and the second cathode positioned on the rear side of the drawing are not shown). The positive electrode tab 441 and the negative electrode tab 411 of the electrode assembly 400 face the same direction and are formed at one end (a) of the electrode assembly 400.

The first negative electrode 401 includes a negative electrode active material coating part 412 on both sides of a plate-shaped current collector, and a negative electrode tab 441 having no active material coated on one end (a) of the current collector is formed. The gas receiving portion 420 is formed in the form of an active material uncoated portion not coated with a negative electrode active material. A cathode active material coating unit 412 on which an electrode active material is coated on a current collector is positioned around the active material uncoated unit. The gas accommodating portion 420 is formed in a strip shape across the center of the electrode assembly in a plane, and the electrode terminal is positioned from the end (b) opposite the end (a) where the electrode tabs (411, 441) are located. The current collector is linearly extended toward the end portion a, and at least a part of the current collector is cut off from the gas receiving portion 420, and a current collector without an electrode active material is applied to a portion adjacent to the end portion a. do. In this structure, the first separation membrane 430 and the second separation membrane are cut out in correspondence to the portion where the current collector is cut off. Also, the second cathode has the same structure as the first cathode.

The anode 440 has a structure in which a gas receiving portion having the same structure as the first cathode and at least a part of the current collector are cut off from the gas receiving portion. In addition, the position of the gas receiving portion formed in the anode 440 coincides with the position of the gas receiving portion 420 formed in the cathodes.

5 is a schematic diagram of an electrode assembly 500 according to another embodiment of the present invention.

Referring to FIG. 5, the electrode assembly 500 is a full cell of a positive electrode 510 / separator 530 / negative electrode 520 structure, and the gas receiving portion 540 of the positive electrode 510 is a flat electrode assembly 500 ) Is formed in a circular shape in the central portion, and the position of the gas receiving portion (not shown) formed in the cathode 520 coincides with the location of the gas receiving portion 540 of the anode 510. In addition, 100% of the current collector is cut off from the gas receiving portion 540, and the separation membrane 530 is cut off in correspondence to the cut-off portion.

Those skilled in the art to which the present invention pertains will be able to apply various applications and modifications within the scope of the present invention based on the above.

Claims (20)

An electrode assembly comprising a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, wherein the battery cell is embedded in a battery case together with an electrolyte,
The electrode assembly is a bicell structure in which a first cathode, a first separator, an anode, a second separator, and a second cathode are stacked, and the electrode assembly is a stack type, or a stack / folding type, or a lamination / stack type structure. ,
The battery case consists of a pouch-shaped case of a laminate sheet comprising a resin layer and a metal layer;
The positive electrode and the negative electrode are each coated with an electrode active material on the surface of the current collector;
A gas accommodating portion that receives gas generated during charging and discharging of the battery cell to prevent expansion of the battery case is formed on the positive electrode and the negative electrode in a polygonal or circular or elliptical shape on the central portion of the electrode assembly in a flat shape,
30% to 80% of the current collector is cut off from the gas receiving portion,
The current collector is cut off in correspondence to the part where the current collector is cut off,
The first separator 430 and the second separator are cut off in correspondence to the part where the current collector has been cut off,
A battery cell characterized in that the position of the gas accommodating portion formed in the anode is inconsistent with the position of the gas accommodating portion formed in the cathode. delete delete The battery cell according to claim 1, wherein the gas accommodating part is formed in the form of an uncoated part of an active material that is not coated with an electrode active material. The battery cell according to claim 4, wherein an active material coating part coated with an electrode active material is disposed on the current collector around the active material uncoated part. delete delete delete delete delete delete delete delete delete delete delete delete delete A battery pack comprising the battery cell according to any one of claims 1, 4 and 5 . A device comprising the battery pack according to claim 19 as a power source.

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