Battery cell for secondary battery

Abstract

The present invention relates to a battery for a secondary battery, and includes a battery cell for a secondary battery, the battery cell comprising, inside a case,: an electrode assembly having a negative electrode current collector, a negative electrode, an electrolyte, a positive electrode, and a positive electrode current collector; and a first compression pad and a second compression pad making contact with one outermost surface of the electrode assembly.

Description

Battery cells for secondary batteries

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0146550, filed October 30, 2023, and Korean Patent Application No. 10-2024-0122509, filed September 9, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a battery cell for a secondary battery, and more particularly, to a battery cell for a secondary battery including a compression pad inside a case.

[0003] As technological development and demand for mobile devices increase, rechargeable secondary batteries are being widely used as a power source for various mobile devices. Furthermore, secondary batteries are also attracting attention as an energy source for electric and hybrid vehicles, which are being proposed as a solution to address air pollution caused by existing gasoline and diesel vehicles.

[0004] Secondary batteries are classified into coin-type batteries, cylindrical batteries, square batteries, and pouch-type batteries depending on the shape of the battery case. Among these, pouch-type batteries are garnering much attention because their exterior is constructed using a pouch outer material composed of a multilayer film of a metal layer (foil) and synthetic resin layers coated on the upper and lower surfaces of the metal layer. This significantly reduces the weight of the battery compared to cylindrical or square batteries that use metal cans, enabling lightweight batteries and allowing for various changes in shape.

[0005] Pouch-type batteries are typically manufactured by activating the battery cells after the battery assembly process. This activation process typically involves pressing the battery cells with a jig and applying current to the cells to a predetermined voltage, charging and discharging them.

[0006] In the manufacture of pouch-type batteries, it is crucial that the battery cells are pressurized with uniform pressure during the cell assembly process. However, due to volume changes in the active material during charging and discharging, contact between solid particles deteriorates, resulting in uneven pressure applied to the battery cells. This deteriorates cell lifespan and impacts battery performance.

[0007] Therefore, in order to achieve excellent performance of all-solid-state batteries, development of a battery cell that can apply uniform pressure to the battery cell is necessary.

[0008] [Previous literature]

[0009] (Patent Document 1) Republic of Korea Patent Publication No. 10-2022-0052032 (April 27, 2022)

[0010] One of the objects of the present invention is to provide a battery cell that allows uniform pressure to be applied during charging and discharging in battery manufacturing.

[0011] Another object of the present invention is to provide a battery cell that absorbs changes in the volume of an electrode when pressurizing a battery cell, thereby suppressing changes in the volume of the entire cell, thereby applying uniform pressure to the battery cell, thereby improving excellent battery life performance and charge / discharge cycles.

[0012] As one embodiment of the present invention, a secondary battery cell is provided, which includes an electrode assembly having a negative electrode current collector, a negative electrode, an electrolyte, a positive electrode, and a positive electrode current collector inside a case, and a first compression pad and a second compression pad that contact an outermost surface of the electrode assembly.

[0013] As one embodiment of the present invention, a secondary battery cell is provided in which the first compression pad and the second compression pad are disposed inside a case.

[0014] As one embodiment of the present invention, a secondary battery cell is provided in which the first compression pad is in contact with one surface of the positive electrode collector and is disposed between the positive electrode collector and one surface of the case.

[0015] As one embodiment of the present invention, a secondary battery cell is provided in which the second compression pad is in contact with one surface of the negative electrode current collector and is disposed between the negative electrode current collector and one surface of the case.

[0016] As one embodiment of the present invention, a secondary battery cell is provided in which the elastic modulus of the first compression pad and the second compression pad is 0.1 GPa to 3.0 GPa.

[0017] As one embodiment of the present invention, a secondary battery cell is provided in which the first compression pad and the second compression pad have a thickness of 0.1 mm to 2.0 mm.

[0018] As one embodiment of the present invention, a secondary battery cell is provided in which the first compression pad and the second compression pad are made of an elastic material.

[0019] As one embodiment of the present invention, a battery cell for a secondary battery is provided, wherein the elastic material includes at least one selected from the group consisting of polytetrafluoroethylene (PTFE), fluoroethylene propylene (FEP), polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), spandex, elastomer, polybutadiene, nitrile rubber, silicone rubber, ethylene-propylene-diene rubber, and ethylene vinyl acetate.

[0020] As one embodiment of the present invention, a secondary battery battery cell is provided, wherein the electrode assembly includes a first negative electrode current collector, a first negative electrode, a first electrolyte, a first positive electrode, a positive electrode current collector, a second positive electrode, a second electrolyte, a second negative electrode, and a second negative electrode current collector, and wherein the first compression pad is disposed between one surface of the first negative electrode current collector and one surface of a case, and the second compression pad is disposed between one surface of the second negative electrode current collector and one surface of the case.

[0021] As one embodiment of the present invention, a secondary battery cell is provided in which the elastic modulus of the first compression pad and the second compression pad is 1.0 GPa to 5.0 GPa.

[0022] As one embodiment of the present invention, a secondary battery cell is provided in which the first compression pad and the second compression pad have a thickness of 0.01 mm to 2.0 mm.

[0023] As one embodiment of the present invention, a secondary battery battery cell is provided in which the thickness of the first compression pad and the second compression pad is 1 / 30 to 1 / 2 of the thickness of the battery cell.

[0024] As one embodiment of the present invention, a battery cell for a secondary battery is provided, wherein the electrode assembly comprises a plurality of electrode assemblies and further includes an intermediate pad disposed between the electrode assemblies.

[0025] As one embodiment of the present invention, a secondary battery cell is provided in which the elastic modulus of the intermediate pad is 1.0 GPa to 3.0 GPa.

[0026] As one embodiment of the present invention, a secondary battery cell is provided in which the thickness of the intermediate pad is 0.01 mm to 0.3 mm.

[0027] As one embodiment of the present invention, a secondary battery cell is provided in which the thickness of the intermediate pad is 1 / 30 to 1 / 3 of the thickness of the battery cell.

[0028] As one embodiment of the present invention, a secondary battery cell is provided in which the electrolyte includes a solid electrolyte.

[0029] As one embodiment of the present invention, a secondary battery cell is provided in which the solid electrolyte includes a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a polymer-based solid electrolyte.

[0030] The battery cell according to the present invention can ensure that uniform pressure is applied to the battery cell during charging and discharging.

[0031] The battery cell according to the present invention can produce an all-solid-state battery with improved life performance.

[0032] The battery cell according to the present invention can improve charge / discharge cycle performance.

[0033] FIG. 1 is a diagram schematically illustrating the structure of a battery cell for a secondary battery according to one embodiment of the present invention.

[0034] FIG. 2 is a diagram schematically illustrating the structure of a battery cell for a secondary battery according to another embodiment of the present invention.

[0035] FIG. 3 is a diagram schematically illustrating the structure of a stack-type secondary battery cell according to another embodiment of the present invention.

[0036] FIG. 4 is a diagram showing the capacity retention rate according to the charge / discharge rate (C-rate) of a battery cell according to Example 1 of the present invention and a battery cell according to Comparative Examples 2 and 4.

[0037] FIG. 5 is a diagram showing the capacity retention rate according to cycle of a battery cell according to Example 1 of the present invention and a battery cell according to Comparative Examples 2 and 4.

[0038] FIG. 6 is a diagram showing the capacity retention rate according to the charge / discharge rate (C-rate) of a battery cell according to Example 2 of the present invention and battery cells according to Comparative Examples 6, 7, and 8.

[0039] FIG. 7 is a diagram showing the capacity retention rate according to cycles of a battery cell according to Example 2 of the present invention and battery cells according to Comparative Examples 6, 7, and 8.

[0040] FIG. 8 is a diagram showing the capacity retention rate according to the charge / discharge rate (C-rate) of battery cells according to Examples 3 and 4 of the present invention and battery cells according to Comparative Examples 9 and 10.

[0041] FIG. 9 is a diagram showing the capacity retention rate according to the cycle of the battery cells according to Examples 3 and 4 of the present invention and the battery cells according to Comparative Examples 9 and 10.

[0042] FIG. 10 is a diagram showing the electrostatic capacity and coulombic efficiency according to the cycle of a battery cell according to Example 5 of the present invention and a battery cell according to Comparative Examples 11 and 12.

[0043] FIG. 11 is a diagram showing the electrostatic capacity and coulombic efficiency according to the cycle of a battery cell according to Example 5 of the present invention and a battery cell according to Comparative Examples 13 and 14.

[0044] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. For convenience of explanation, the drawings may show exaggerated representations of all or part of the components.

[0045] In addition, it will be apparent to those skilled in the art that the present invention is not limited to the attached drawings or the contents described in this specification, and that the present invention can be implemented in various forms without departing from the technical spirit of the present invention.

[0046]

[0047] In the battery cell manufacturing process, contact between solid particles within the electrode composite layer is important for improving battery life performance and charge / discharge cycles, and a process of pressurizing the battery cell at high pressure is necessary to ensure contact between solid particles within the electrode active material.

[0048] However, due to the change in volume of the electrode active material during charging and discharging of the battery cell, the contact between solid particles in the electrode active material is reduced, causing a change in volume of the entire cell, which makes it difficult to apply uniform pressure.

[0049] To solve this problem, the inventors of the present invention have completed a battery cell that absorbs the change in volume of the electrode during the pressurizing process, thereby suppressing the change in volume of the entire cell, thereby applying uniform pressure to the battery cell, thereby improving excellent battery life performance and charge / discharge cycles.

[0050] Referring to the drawings below, the configuration of a secondary battery cell according to one embodiment of the present invention will be described in detail.

[0051] FIG. 1 is a diagram schematically illustrating the structure of a secondary battery cell (100) according to one embodiment of the present invention.

[0052] Referring to FIG. 1, a secondary battery cell (100) includes an electrode assembly (110) having a negative electrode current collector (111), a negative electrode (112), an electrolyte (113), a positive electrode (114), and a positive electrode current collector (115) inside a case (101), and may include a first compression pad (121) in contact with one surface of the positive electrode current collector (115) and a second compression pad (122) in contact with one surface of the negative electrode current collector (111).

[0053] The first compression pad (121) and the second compression pad (122) can be placed on the outermost side of the electrode assembly (110).

[0054] The above first compression pad (121) and second compression pad (122) can be placed inside the case (101).

[0055] The above first compression pad (121) can be placed between the positive electrode collector (115) and one side of the case (101).

[0056] The above second compression pad (122) can be placed between the negative electrode collector (111) and one side of the case (101).

[0057] Conventionally, when pressurizing a battery cell, a compression pad is placed outside the case containing the electrode assembly, and then pressurized using a jig. However, when the compression pad is placed outside the case as described above, when pressurizing the battery cell, the electrodes inside the case and the aluminum pouch come into direct contact, resulting in poor contact between particles due to changes in the electrode volume.

[0058] On the other hand, the secondary battery battery cell (100) according to one embodiment of the present invention includes a compression pad (121, 122) inside the case (101), and in particular, by arranging the compression pad (121, 122) between the electrode (111, 115) inside the case (101) and the aluminum pouch (101), the volume change of the electrode can be absorbed to uniformly apply pressure to the battery cell (100). As a result, the secondary battery battery cell (100) can improve contact between solid particles in the electrode composite layer, and can improve excellent battery life performance and charge / discharge cycles.

[0059] According to one embodiment of the present invention, the modulus of elasticity of the first compression pad (121) and the second compression pad (122) may be 0.1 GPa to 3.0 GPa. More specifically, the elastic modulus of the first compression pad (121) and the second compression pad (122) may be 0.1 GPa or more, 0.2 GPa or more, 0.3 GPa or more, 0.4 GPa or more, 0.5 GPa or more, 0.6 GPa or more, 0.7 GPa or more, 0.8 GPa or more, 0.9 GPa or more, 1.0 GPa or more, or 3.0 GPa or less, 2.9 GPa or less, 2.8 GPa or less, 2.7 GPa or less, 2.6 GPa or less, 2.5 GPa or less, 2.4 GPa or less, 2.3 GPa or less, 2.2 GPa or less, 2.1 GPa or less, or 2.0 GPa or less.

[0060] If the elastic modulus of the first compression pad (121) and the second compression pad (122) is less than 0.1 GPa or more than 3.0 GPa, there is a problem that the battery life is reduced because the volume change of the electrode cannot be absorbed.

[0061] According to one embodiment of the present invention, the first compression pad (121) and the second compression pad (122) may be made of an elastic material. The elastic material may include at least one selected from the group consisting of polytetrafluoroethylene (PTFE), fluoroethylene propylene (FEP), polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), spandex, elastomer, polybutadiene, nitrile rubber, silicone rubber, ethylene-propylene-diene rubber, and ethylene vinyl acetate, but is not limited thereto.

[0062] According to one embodiment of the present invention, the thickness of the first compression pad (121) and the second compression pad (122) may be 0.1 mm to 2.0 mm. More specifically, the thickness of the first compression pad (121) and the second compression pad (122) is 0.1 mm or more, 0.15 mm or more, 0.2 mm or more, 0.25 mm or more, 0.3 mm or more, 0.35 mm or more, 0.4 mm or more, 0.45 mm or more, 0.5 mm or more, 0.55 mm or more, 0.6 mm or more, 0.65 mm or more, 0.7 mm or more, 0.75 mm or more, 0.8 mm or more, 0.85 mm or more, 0.9 mm or more, 0.95 mm or more, 1.0 mm or more, or 2.0 mm or less, 1.95 mm or less, 1.9 mm or less, 1.85 mm or less, 1.8 mm or less, 1.75 mm or less, 1.7 mm or less, 1.65 mm or less, 1.6 mm or less, 1.55 mm It may be less than, 1.5 mm or less, 1.45 mm or less, 1.4 mm or less, 1.35 mm or less, 1.3 mm or less, 1.25 mm or less, 1.2 mm or less, 1.15 mm or less, 1.1 mm or less, 1.05 mm or less, or 1.0 mm or less.

[0063] According to one embodiment of the present invention, the electrolyte may include a solid electrolyte. The solid electrolyte may include a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a polymer-based solid electrolyte. The solid electrolyte may be in the form of particles.

[0064] The above sulfide-based solid electrolyte contains sulfur (S) and has the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and may include Li-PS-based glass or Li-PS-based glass ceramic.

[0065] Specifically, the sulfide-based solid electrolyte may include at least one selected from the group consisting of Li6PS5Cl, Li6PS5Br, Li6PS5I, Li2S-P2S5, Li2S-LiI-P2S5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2S-Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2S5, Li2S-P2S5-SiS2, Li2S-P2S5-SnS, Li2S-P2S5-Al2S3, Li2S-GeS2, and Li2S-GeS2-ZnS, and preferably may include at least one selected from the group consisting of Li6PS5Cl, Li6PS5Br, and Li6PS5I. The above Li6PS5Cl, Li6PS5Br, and Li6PS5I may be argyrodite type solid electrolytes. In addition, the sulfide-based solid electrolyte may be in a form doped with trace elements, for example, Li6PS5Cl may be additionally doped with bromine (Br).

[0066] The above oxide-based solid electrolyte may contain oxygen (O) and have the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table. For example, an LLTO-based compound, Li6La2CaTa2O 12 , Li6La2ANb2O 12 (A is Ca or Sr), Li2Nd3TeSbO 12 , Li3BO 2.5 N 0.5 , Li9SiAlO8, LAGP compounds, LATP compounds, Li1 +x Ti 2-x Al x Si y (PO4) 3-y (where, 0≤x≤1, 0≤y≤1), LiAl x Zr 2-x (PO4)3(where, 0≤x≤1, 0≤y≤1), LiTi x Zr 2-x(PO4)3 (wherein, 0≤x≤1, 0≤y≤1), may include at least one selected from among LISICON compounds, LIPON compounds, perovskite compounds, NASICON compounds, and LLZO compounds.

[0067] The above polymer-based solid electrolyte is a polymer electrolyte material formed by adding a polymer resin to a composite of a lithium salt and a polymer resin, that is, a solvated lithium salt, and is about 1x10 -7 S / cm or more, preferably about 1x10 -5 It can exhibit ionic conductivity of S / cm or more.

[0068] Non-limiting examples of the polymer resin include polyether polymers, polycarbonate polymers, acrylate polymers, polysiloxane polymers, phosphazene polymers, polyethylene derivatives, alkylene oxide derivatives such as polyethylene oxide, phosphate ester polymers, polyagitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, polymers containing ionic dissociation groups, etc., and may include one or more of these. In addition, the polymer electrolyte may include, as a polymer resin, a branched copolymer in which an amorphous polymer such as PMMA, polycarbonate, polysiloxane (PDMS) and / or phosphazene is copolymerized as a comonomer in a polyethylene oxide (PEO) main chain, a comb-like polymer, and a cross-linked polymer resin, and may include one or more of these.

[0069] In the electrolyte of the present invention, the lithium salt mentioned above is an ionizable lithium salt and is Li + X - It can be expressed as . There is no particular limitation on the anion of these lithium salts, but F - , Cl - , Br - , I - , NO3 -, N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - , (CF3CF2SO2)2N - Examples include:

[0070] The battery cell (100) according to the present invention includes the first compression pad (121) and the second compression pad (122) of the present invention described above in the case (101), thereby absorbing the change in volume of the electrode, thereby improving poor contact between solid particles in the electrode active material, and exhibiting excellent battery performance.

[0071] The above positive electrode (114) may have a structure in which a positive electrode composite layer containing a positive electrode active material is formed on a positive electrode current collector (115).

[0072] The above-mentioned positive electrode current collector (115) is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and may include, for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc.

[0073] In addition, the positive electrode composite layer contains a positive electrode active material, a conductive material, a binder, and a solid electrolyte, and may further contain additives in some cases.

[0074] In addition, the conductive material is not particularly limited as long as it is conductive without causing a chemical change in the battery, and specifically, graphite, a carbon-based material, a metal powder or metal fiber, a needle-shaped or branch-shaped conductive whisker, a conductive metal oxide, a conductive polymer, and any one of these or a mixture thereof may be used. More specifically, graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black, and carbon fiber; metal powder or metal fiber such as copper, nickel, aluminum, and silver; Examples of conductive whiskers include needle- or branch-shaped whiskers such as zinc oxide whiskers, calcium carbonate whiskers, titanium dioxide whiskers, silicon oxide whiskers, silicon carbide whiskers, aluminum borate whiskers, magnesium borate whiskers, potassium titanate whiskers, silicon nitride whiskers, silicon carbide whiskers, and alumina whiskers; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives; and any one of these or a mixture of two or more thereof may be used.

[0075] In addition, the binder for the positive electrode is one selected from the group consisting of N,N-bis[3-(triethoxysilyl)propyl]urea, polyethylene oxide (PEO), poly(vinylidene fluoride) (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP), or a mixture of two or more thereof, N,N-bis[3-(triethoxysilyl)propyl]urea, polyethylene oxide (PEO), poly(vinylidene fluoride) (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP), acrylonitrile-based styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), methyl methacrylate butadiene rubber (MBR), butadiene rubber (BR), and the like, conjugated diene rubber latex, It may be any one selected from the group consisting of carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene (PTFE), polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluoroelastomer, various copolymers, etc., or a mixture of two or more thereof.

[0076] In addition, the negative electrode (112) may have a structure in which a negative electrode composite layer containing a negative electrode active material is formed on a negative electrode current collector (111).

[0077] The above negative electrode current collector (111) is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and may include, for example, stainless steel, copper, nickel, titanium, calcined carbon, or stainless steel surface-treated with carbon, nickel, titanium, silver, etc.

[0078] In addition, the negative electrode composite layer contains a negative electrode active material, a conductive material, a binder, and a solid electrolyte, and may further contain additives in some cases.

[0079] At this time, the negative electrode active material may be one selected from the group consisting of lithium metal, lithium alloy, lithium metal composite oxide, lithium-containing titanium composite oxide (LTO), and combinations thereof. Here, the lithium alloy may be an alloy composed of lithium and at least one metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al, and Sn. In addition, the lithium metal composite oxide is an oxide (MeOx) of any one metal (Me) selected from the group consisting of lithium and Si, Sn, Zn, Mg, Cd, Ce, Ni, and Fe, and for example, Li x Fe2O3(0 <x≤1) 또는 Li x WO2(0 <x≤1)일 수 있다.

[0080] In addition, the negative electrode active material is Sn x Me 1-x Me' y O z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, elements of group 1, 2, and 3 of the periodic table, halogens; 0 <x≤1; 1≤y≤3; 1≤z≤8) 등의 금속 복합 산화물; SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4및 Bi2O5등의 산화물 등을 사용할 수 있고, 결정질 탄소, 비정질 탄소 또는 탄소 복합체와 같은 탄소계 음극활물질이 단독으로 또는 2종 이상이 혼용되어 사용될 수 있다.

[0081] In addition, examples of the conductive material include nickel powder, cobalt oxide, titanium oxide, carbon, etc. As for the carbon, any one or more selected from the group consisting of Ketjen black, acetylene black, furnace black, graphite, carbon fiber, and fullerene may be mentioned.

[0082] In addition, the binder for the negative electrode is one selected from the group consisting of N,N-bis[3-(triethoxysilyl)propyl]urea, polyethylene oxide (PEO), poly(vinylidene fluoride) (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) or a mixture of two or more thereof, N,N-bis[3-(triethoxysilyl)propyl]urea, polyethylene oxide (PEO), poly(vinylidene fluoride) (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP), conjugated diene rubber latex such as styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), methyl methacrylate butadiene rubber (MBR), butadiene rubber (BR), carboxymethyl cellulose (CMC), It may be one selected from the group consisting of starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluororubber, various copolymers, etc., or a mixture of two or more thereof.

[0083] FIG. 2 is a schematic diagram illustrating the structure of a secondary battery cell (200) according to another embodiment of the present invention. While the case is not depicted separately in FIG. 2 for convenience, the present invention is not limited to the omission of the case. Furthermore, in the embodiment of FIG. 2, any overlapping content described in FIG. 1 is omitted, but this does not necessarily exclude such content.

[0084] Referring to Fig. 2, a secondary battery cell (200) may be configured in a bi-cell form. In this case, the bi-cell may be a C-type bi-cell.

[0085] A secondary battery cell (200) according to one embodiment of the present invention may include an electrode assembly (210) having a first negative electrode current collector (211), a first negative electrode (212), a first electrolyte (213), a first positive electrode (214), a positive electrode current collector (215), a second positive electrode (216), a second electrolyte (217), a second negative electrode (218), and a second negative electrode current collector (219) inside a case.

[0086] At this time, the electrode assembly (210) can be manufactured as follows. In one embodiment, a first negative electrode current collector (211), a first negative electrode (212), and a first electrolyte (213) are transferred to form a first assembly, and similarly, a second negative electrode current collector (219), a second negative electrode (218), and a second electrolyte (217) are transferred to form a second assembly identical to the first assembly, and then a frame (230) is placed between the first assembly and the second assembly. Then, each frame (230) is combined to form a third assembly, and then a first positive electrode (214), a positive electrode current collector (215), and a second positive electrode (216) are placed in the space formed by the frame (230) of the third assembly, thereby manufacturing the electrode assembly (210).

[0087] Additionally, it may include a first compression pad (221) in contact with one surface of the first negative electrode collector (211) and a second compression pad (122) in contact with one surface of the second negative electrode collector (219).

[0088] In one embodiment, the first compression pad (221) and the second compression pad (222) may be placed on the outermost surface of the electrode assembly (200).

[0089] The above first compression pad (221) and second compression pad (222) can be placed inside the case.

[0090] The above first compression pad (221) can be placed between one side of the first negative electrode collector (211) and one side of the case.

[0091] The second compression pad (222) may be placed between one surface of the second negative electrode collector (219) and one surface of the case. According to one embodiment of the present invention, the elastic modulus of the first compression pad (221) and the second compression pad (222) may be 1.0 GPa to 5.0 GPa. More specifically, the elastic modulus of the first compression pad (221) and the second compression pad (222) may be 1.0 GPa or more, 1.1 GPa or more, 1.2 GPa or more, 1.3 GPa or more, 1.4 GPa or more, 1.5 GPa or more, 1.6 GPa or more, 1.7 GPa or more, 1.8 GPa or more, 1.9 GPa or more, 2.0 GPa or more, or 5.0 GPa or less, 4.9 GPa or less, 4.8 GPa or less, 4.7 GPa or less, 4.6 GPa or less, 4.5 GPa or less, 4.4 GPa or less, 4.3 GPa or less, 4.2 GPa or less, 4.1 GPa or less, 4.0 GPa or less. Preferably, the elastic modulus of the first compression pad (221) and the second compression pad (222) may be 1.0 GPa or more and 3.0 GPa or less.

[0092] According to one embodiment of the present invention, the thickness of the first compression pad (221) and the second compression pad (222) may be 0.01 mm to 2.0 mm. More specifically, the thickness of the first compression pad (221) and the second compression pad (222) is 0.01 mm or more, 0.02 mm or more, 0.03 mm or more, 0.04 mm or more, 0.05 mm or more, 0.06 mm or more, 0.07 mm or more, 0.08 mm or more, 0.09 mm or more, 0.1 mm or more, 0.15 mm or more, 0.2 mm or more, 0.25 mm or more, 0.3 mm or more, 0.35 mm or more, 0.4 mm or more, 0.45 mm or more, 0.5 mm or more, 0.55 mm or more, 0.6 mm or more, 0.65 mm or more, 0.7 mm or more, 0.75 mm or more, 0.8 mm or more, 0.85 mm or more, 0.9 mm or more, 0.95 mm or more, 1.0 mm or more, It may be 2.0 mm or less, 1.95 mm or less, 1.9 mm or less, 1.85 mm or less, 1.8 mm or less, 1.75 mm or less, 1.7 mm or less, 1.65 mm or less, 1.6 mm or less, 1.55 mm or less, 1.5 mm or less, 1.45 mm or less, 1.4 mm or less, 1.35 mm or less, 1.3 mm or less, 1.25 mm or less, 1.2 mm or less, 1.15 mm or less, 1.1 mm or less, 1.05 mm or less, or 1.0 mm or less.

[0093] Alternatively, according to one embodiment of the present invention, the thickness of the first compression pad (221) and the second compression pad (222) may have a ratio of 1 / 30 to 1 / 2 of the thickness of the battery cell (200). More specifically, the thickness of the first compression pad (221) and the second compression pad (222) may be 1 / 30 or more, 1 / 25 or more, 1 / 20 or more, 1 / 15 or more, 1 / 10 or more, 1 / 5 or more, 1 / 4 or more, 1 / 3 or more, and 1 / 2 or less of the thickness of the battery cell (200), respectively.

[0094] FIG. 3 is a schematic diagram illustrating the structure of a stack-type secondary battery cell (300) according to another embodiment of the present invention. Although the case is not separately illustrated in FIG. 3 , it is not omitted during implementation. Furthermore, in the embodiment of FIG. 3 , any content overlapping with that described in FIGS. 1 and 2 is omitted, but this does not necessarily exclude it.

[0095] Referring to FIG. 3, one embodiment of the present invention may include a plurality of electrode assemblies (310-1 to 310-n) configured in a stack form, and may further include an intermediate pad (340) disposed between the plurality of electrode assemblies (310-1 to 310-n). At this time, the configuration of the individual electrode assemblies (310-1 to 310-n) may be configured with a first negative electrode current collector, a first negative electrode, a first electrolyte, a first positive electrode, a positive electrode current collector, a second positive electrode, a second electrolyte, a second negative electrode, and a second negative electrode current collector, as described in FIG. 2. Meanwhile, in the drawing of FIG. 3, for convenience, the intermediate pad (340) is illustrated as being separated from each electrode assembly (310-1 to 310-n), but in reality, it is implemented so as to be in contact with each other during the stacking process.

[0096] As an example, FIG. 3 illustrates a form in which at least four electrode assemblies (310-1 to 310-n) are stacked, and in this case, at least three intermediate pads (340) are included between each electrode assembly (310-1 to 310-n). First and second compression pads (321, 322) may be arranged on the outermost surface of the battery cell (300).

[0097] According to one embodiment of the present invention, the elastic modulus of the intermediate pad (340) may be 1.0 GPa to 3.0 GPa. More specifically, the elastic modulus of the intermediate pad (340) may be 1.0 GPa or more, 1.1 GPa or more, 1.2 GPa or more, 1.3 GPa or more, 1.4 GPa or more, 1.5 GPa or more, 1.6 GPa or more, 1.7 GPa or more, 1.8 GPa or more, 1.9 GPa or more, 2.0 GPa or more, or 3.0 GPa or less, 2.9 GPa or less, 2.8 GPa or less, 2.7 GPa or less, 2.6 GPa or less, 2.5 GPa or less, 2.4 GPa or less, 2.3 GPa or less, 2.2 GPa or less, 2.1 GPa or less, 2.0 GPa or less.

[0098] In addition, according to one embodiment of the present invention, the thickness of the intermediate pad (340) may be 0.01 mm to 0.3 mm. More specifically, the thickness of the intermediate pad (340) may be 0.01 mm or more, 0.02 mm or more, 0.03 mm or more, 0.04 mm or more, 0.05 mm or more, 0.06 mm or more, 0.07 mm or more, 0.08 mm or more, 0.09 mm or more, 0.1 mm or more, or 0.3 mm or less, 0.29 mm or less, 0.28 mm or less, 0.27 mm or less, 0.26 mm or less, 0.25 mm or less, 0.24 mm or less, 0.23 mm or less, 0.22 mm or less, 0.21 mm or less, 0.2 mm or less.

[0099] Alternatively, according to one embodiment of the present invention, the thickness of the intermediate pad (340) may have a ratio of 1 / 30 to 1 / 3 of the thickness of the battery cell (300). More specifically, the thickness of the intermediate pad (340) may be 1 / 30 or more, 1 / 25 or more, 1 / 20 or more, 1 / 15 or more, 1 / 10 or more, 1 / 5 or more, 1 / 4 or more, and 1 / 3 or less of the thickness of the battery cell (300), respectively.

[0100] Meanwhile, the thickness and elastic modulus of the first compression pad (321) and the second compression pad (322) are as described in FIG. 2.

[0101] Hereinafter, the present invention will be described in more detail through examples and experimental examples.

[0102] However, the following examples and experimental examples are only illustrative of the present invention, and the content of the present invention is not limited to the following examples and experimental examples.

[0103] Example 1

[0104] As shown in Fig. 1, an electrode assembly was manufactured by sequentially stacking a negative electrode current collector, a negative electrode, a solid electrolyte, a positive electrode, and a positive electrode current collector. Thereafter, the electrode assembly was pressed using warm isostatic pressure (WIP).

[0105] In the sintered electrode assembly, a first compression pad and a second compression pad were attached to the outermost surfaces of the negative current collector and the positive current collector, respectively, and sealed with a pouch to manufacture a battery cell.

[0106] Example 2

[0107] As shown in Fig. 2, two assemblies were manufactured by transferring a negative electrode current collector, a negative electrode, and a solid electrolyte, and a frame was placed on the two assemblies and then joined. An electrode assembly was manufactured by sequentially stacking a positive electrode, a positive electrode current collector, and a positive electrode in the interstitial space created by the frame of the joined assembly.

[0108] Afterwards, the electrode assembly was heated by warm isostatic pressing, and the first and second compression pads were attached to the outermost surface of each negative current collector in the sintered electrode assembly, and sealed in a pouch to manufacture a battery cell.

[0109] Example 3

[0110] In the above Example 2, a battery cell was manufactured using the same method as in the above Example 2, except that the elastic modulus of the first and second compression pads was each configured to be 1 GPa.

[0111] Example 4

[0112] In the above Example 2, a battery cell was manufactured using the same method as in the above Example 2, except that the elastic modulus of the first and second compression pads was each configured to be 2 GPa.

[0113] Example 5

[0114] As shown in Fig. 3, a plurality of electrode assemblies were configured in a stack form, and the plurality of electrode assemblies are the same as Example 2 of Fig. 2. An intermediate pad having an elastic modulus of 2 GPa and a thickness of 0.2 mm was placed between the plurality of electrode assemblies, and a first compression pad and a second compression pad having an elastic modulus of 3 GPa and a thickness of 0.3 mm were placed on the outermost surface of the battery cell, respectively.

[0115]

[0116] Comparative Example 1

[0117] In the electrode assembly according to Example 1, a battery cell for a secondary battery was manufactured using the same method as in Example 1, except that the battery cell did not include both the first and second compression pads.

[0118] Comparative Example 2

[0119] In the electrode assembly according to Example 1, a battery cell was manufactured using the same method as in Example 1, except that a first compression pad was laminated on the outermost surface of the positive electrode current collector and then bonded to manufacture the battery cell.

[0120] Comparative Example 3

[0121] In the electrode assembly according to Example 1, a battery cell was manufactured using the same method as in Example 1, except that a second compression pad was laminated on the outermost surface of the negative electrode current collector and then bonded to manufacture the battery cell.

[0122] Comparative Example 4

[0123] A battery cell including an electrode assembly according to Example 1 was manufactured using the same method as in Example 1, except that the first compression pad was placed outside the pouch in contact with the positive electrode current collector and the second compression pad was placed outside the pouch in contact with the negative electrode current collector.

[0124] Comparative Example 5

[0125] In the electrode assembly according to Example 2, a battery cell was manufactured using the same method as in Example 2, except that a secondary battery battery cell was manufactured without including both the first and second compression pads.

[0126] Comparative Example 6

[0127] In the electrode assembly according to Example 2, a battery cell was manufactured using the same method as in Example 2, except that a second compression pad was laminated on the outermost surface of the second negative electrode collector and then bonded to manufacture the battery cell.

[0128] Comparative Example 7

[0129] In the electrode assembly according to Example 2, a battery cell was manufactured using the same method as in Example 2, except that a first compression pad was laminated on the outermost surface of the first negative electrode collector and then bonded to manufacture a battery cell.

[0130] Comparative Example 8

[0131] A battery cell including an electrode assembly according to Example 2 was manufactured using the same method as in Example 2, except that a first compression pad was placed outside the pouch in contact with the first negative electrode current collector, and a second compression pad was placed outside the pouch in contact with the second negative electrode current collector.

[0132] Comparative Example 9

[0133] In Example 2, a battery cell was manufactured using the same method as in Example 2, except that the elastic moduli of the first and second compression pads were each configured to be 3 GPa.

[0134] Comparative Example 10

[0135] In Example 2, a battery cell was manufactured using the same method as in Example 2, except that the elastic moduli of the first and second compression pads were each configured to be 4 GPa.

[0136] Comparative Example 11

[0137] In a stack type battery cell according to Example 5, an intermediate pad having an elastic modulus of 2 GPa and a thickness of 0.2 mm was placed between a plurality of electrode assemblies, and a first compression pad and a second compression pad having an elastic modulus of 4 GPa and a thickness of 0.3 mm were placed on the outermost surface of the stack cell, respectively.

[0138] Comparative Example 12

[0139] In a stack type battery cell according to Example 5, an intermediate pad having an elastic modulus of 2 GPa and a thickness of 0.2 mm was placed between a plurality of electrode assemblies, and a first compression pad and a second compression pad having an elastic modulus of 5 GPa and a thickness of 0.3 mm were placed on the outermost surface of the stack cell, respectively.

[0140] Comparative Example 13

[0141] In a stack type battery cell according to Example 5, an intermediate pad having an elastic modulus of 2 GPa and a thickness of 0.2 mm was placed between a plurality of electrode assemblies, and a first compression pad and a second compression pad having an elastic modulus of 3 GPa and a thickness of 0.2 mm were placed on the outermost surface of the stack cell, respectively.

[0142] Comparative Example 14

[0143] In a stack type battery cell according to Example 5, an intermediate pad having an elastic modulus of 2 GPa and a thickness of 0.2 mm was placed between a plurality of electrode assemblies, and a first compression pad and a second compression pad having an elastic modulus of 3 GPa and a thickness of 0.4 mm were placed on the outermost surface of the stack cell, respectively.

[0144]

[0145] Experimental Example 1: Battery Performance Evaluation 1

[0146] FIG. 4 is a diagram showing the capacity retention rate according to the charge / discharge rate (C-rate) of a battery cell according to Example 1 of the present invention and a battery cell according to Comparative Examples 2 and 4.

[0147] FIG. 5 is a diagram showing the capacity retention rate according to cycle of a battery cell according to Example 1 of the present invention and a battery cell according to Comparative Examples 2 and 4.

[0148] Referring to FIGS. 4 and 5, the battery cell manufactured by Example 1 includes first and second compression pads on the outermost surface of the electrode assembly, respectively, and was confirmed to have superior charge / discharge rates and capacity retention rates over multiple cycles compared to the battery cell manufactured by Comparative Example 2, which includes the first compression pad only on the outermost surface of the positive electrode current collector, or Comparative Example 4, which includes the first and second compression pads on the outside of the cell in contact with the positive electrode current collector and the negative electrode current collector.

[0149] In particular, at a C-rate of 1.0C, Comparative Example 2 showed a capacity retention rate of about 95%, while Comparative Example 4 showed a capacity retention rate of about 92.75%, while Example 1 showed a higher capacity retention rate of about 95.5%. In addition, at 92 cycles, Comparative Example 2 showed a capacity retention rate of about 95.75%, while Comparative Example 4 showed a capacity retention rate of about 96%, while Example 1 showed a higher capacity retention rate of about 96.75%.

[0150] Although not shown in the drawing, the battery cell manufactured by Comparative Example 1, which does not include a compression pad inside or outside the cell, and the battery cell manufactured by Comparative Example 3, which includes a second compression pad only on the outermost surface of the negative electrode current collector, had a short circuit at the beginning of the charging process, making comparison of experimental data impossible.

[0151]

[0152] Experimental Example 2: Battery Performance Evaluation 2

[0153] FIG. 6 is a diagram showing the capacity retention rate according to the charge / discharge rate (C-rate) of a battery cell according to Example 2 of the present invention and battery cells according to Comparative Examples 6, 7, and 8.

[0154] FIG. 7 is a diagram showing the capacity retention rate according to cycles of a battery cell according to Example 2 of the present invention and battery cells according to Comparative Examples 6, 7, and 8.

[0155] Referring to FIGS. 6 and 7, the battery cell manufactured by Example 2 includes first and second compression pads on the outermost surface of the electrode assembly, respectively, and was confirmed to have superior charge / discharge rate and capacity retention rate over multiple cycles compared to the battery cell manufactured by Comparative Example 6, which includes the second compression pad only on the outermost surface of the second negative current collector, Comparative Example 7, which includes the first compression pad only on the outermost surface of the first negative current collector, or Comparative Example 8, which includes the first and second compression pads on the outside of the cell in contact with the first and second negative current collectors.

[0156] In particular, at a C-rate of 1.0C, Comparative Example 6, Comparative Example 7, and Comparative Example 8 showed capacity retention rates of about 90%, about 89%, and about 91.75%, respectively, while Example 2 was confirmed to have a higher capacity retention rate of about 92.25%. In addition, at 200 cycles, Comparative Example 6 showed capacity retention rates of about 87.5%, Comparative Example 7 showed capacity retention rates of about 87%, and Comparative Example 8 showed capacity retention rates of about 89%, respectively, while Example 2 was confirmed to have a higher capacity retention rate of about 90%.

[0157] Although not shown in the drawing, the battery cell manufactured by Comparative Example 5, which did not include compression pads inside and outside the cell, had a short circuit at the beginning of the charging process, making comparison of experimental data impossible.

[0158]

[0159] Experimental Example 3: Battery Performance Evaluation 3

[0160] FIG. 8 is a diagram showing the capacity retention rate according to the charge / discharge rate (C-rate) of battery cells according to Examples 3 and 4 of the present invention and battery cells according to Comparative Examples 9 and 10.

[0161] FIG. 9 is a diagram showing the capacity retention rate according to the cycle of the battery cells according to Examples 3 and 4 of the present invention and the battery cells according to Comparative Examples 9 and 10.

[0162] Referring to FIGS. 8 and 9, the battery cell manufactured by Example 3, which includes first and second compression pads each having an elastic modulus of 1 GPa at the outermost portion of the electrode assembly, was confirmed to have superior charge / discharge rate and capacity retention rate over multiple cycles compared to the battery cell manufactured by Example 4 having an elastic modulus of 2 GPa at the outermost portion of the electrode assembly, Comparative Example 9 having an elastic modulus of 3 GPa at the outermost portion of the electrode assembly, or Comparative Example 10 having an elastic modulus of 3 GPa at the outermost portion of the electrode assembly.

[0163] In particular, at a C-rate of 1.0C, Example 4 showed a capacity retention rate of about 89%, Comparative Example 9 showed a capacity retention rate of about 89%, and Comparative Example 10 showed a capacity retention rate of about 84.5%, while Example 3 showed a higher capacity retention rate of about 89.5%. In addition, at 200 cycles, Example 4 showed a capacity retention rate of about 89.5%, Comparative Example 9 showed a capacity retention rate of about 89%, and Comparative Example 10 showed a capacity retention rate of about 88.5%, while Example 3 showed a higher capacity retention rate of about 90%.

[0164] Through this, it was confirmed that when the elastic modulus of the first and second compression pads exceeds 3 GPa, the hardness of the compression pads becomes excessively high, which is likely to reduce the uniformity of the driving pressure. It was confirmed that this is suspected to be because the internal resistance of the battery cell increases due to the uneven pressure applied inside the battery cell, which consequently hinders smooth ion movement, thereby reducing the charge / discharge performance of the battery.

[0165] Although not shown in the drawing, the battery cell manufactured by Comparative Example 5, which did not include compression pads inside and outside the cell, had a short circuit at the beginning of the charging process, making comparison of experimental data impossible.

[0166]

[0167] Experimental Example 4: Battery Performance Evaluation 4 (Comparison of Cell Performance by Elastic Modulus)

[0168] FIG. 10 is a diagram showing the electrostatic capacity and coulombic efficiency according to the cycle of a battery cell according to Example 5 of the present invention and a battery cell according to Comparative Examples 11 and 12.

[0169] Referring to FIG. 10, the battery cell manufactured according to Example 5 includes an intermediate pad having the same thickness (0.2 mm) and elastic modulus (2 GPa) as the battery cells according to Comparative Examples 11 and 12. In addition, Example 5 includes first and second compression pads having the same thickness (0.3 mm) as those of Comparative Examples 11 and 12. However, the elastic moduli of the first and second compression pads of Example 5 and Comparative Examples 11 and 12 are configured to be different, respectively.

[0170] Under these conditions, it was confirmed that the battery cell of Example 5 having an elastic modulus of 3 GPa had equal or superior electrostatic capacity and coulombic efficiency according to cycle of the battery cell compared to Comparative Examples 11 and 12 having elastic moduli of 4 GPa and 5 GPa, respectively.

[0171] In particular, it was confirmed that Example 5 had a higher capacitance of about 180 mAh / g, while Comparative Example 11 and Comparative Example 12 had capacitances of about 177 mAh / g and about 173 mAh / g, respectively, around the 60th cycle.

[0172]

[0173] Experimental Example 5: Battery Performance Evaluation 5 (Cell Performance Comparison by Outermost Pad Thickness)

[0174] FIG. 11 is a diagram showing the electrostatic capacity and coulombic efficiency according to the cycle of a battery cell according to Example 5 of the present invention and a battery cell according to Comparative Examples 13 and 14.

[0175] Referring to FIG. 11, the battery cell manufactured according to Example 5 includes an intermediate pad having the same thickness (0.2 mm) and elastic modulus (2 GPa) as the battery cells according to Comparative Examples 13 and 14. In addition, Example 5 includes first and second compression pads having the same elastic modulus (3 GPa) as those of Comparative Examples 14 and 15. However, the thicknesses of the first and second compression pads of Example 5 and Comparative Examples 13 and 14 were configured to be different, respectively.

[0176] Under these conditions, it was confirmed that the battery cell of Example 5, in which the first and second compression pads have a thickness of 0.3 mm, has a cycle-dependent capacitance and coulombic efficiency that are equal to or superior to those of Comparative Examples 14 and 15, in which the first and second compression pads have a thickness of 0.2 mm and 0.4 mm, respectively.

[0177] In particular, it was confirmed that Example 5 had a higher capacitance of about 178 mAh / g, while Comparative Example 13 and Comparative Example 14 had capacitances of about 176 mAh / g and about 174 mAh / g, respectively, around 100 cycles.

[0178] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0179] [Explanation of symbols]

[0180] 100: Secondary battery

[0181] 101: Case

[0182] 110: Electrode assembly

[0183] 111: Negative current collector

[0184] 112: Cathode

[0185] 113: Electrolyte

[0186] 114: Bipolar

[0187] 115: Positive current collector

[0188] 121: Pad 1

[0189] 122: Second Pad

Claims

1. An electrode assembly comprising a negative electrode current collector, a negative electrode, an electrolyte, a positive electrode, and a positive electrode current collector inside a case, A secondary battery cell comprising a first compression pad and a second compression pad that are in contact with the outermost surface of the electrode assembly.

2. In paragraph 1, A secondary battery cell, wherein the first compression pad and the second compression pad are placed inside the case.

3. In paragraph 1, A secondary battery cell, wherein the first compression pad is in contact with one surface of the positive electrode collector and is positioned between the positive electrode collector and one surface of the case.

4. In paragraph 1, A secondary battery cell, wherein the second compression pad is in contact with one surface of the negative electrode collector and is positioned between the negative electrode collector and one surface of the case.

5. In paragraph 1, A secondary battery cell, wherein the elastic modulus of the first compression pad and the second compression pad is 0.1 GPa to 3.0 GPa.

6. In paragraph 1, A secondary battery cell, wherein the thickness of the first compression pad and the second compression pad is 0.1 mm to 2.0 mm.

7. In paragraph 1, A secondary battery cell, wherein the first compression pad and the second compression pad are made of an elastic material.

8. In paragraph 7, A secondary battery cell, wherein the elastic material comprises at least one selected from the group consisting of polytetrafluoroethylene (PTFE), fluoroethylene propylene (FEP), polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), spandex, elastomer, polybutadiene, nitrile rubber, silicone rubber, ethylene-propylene-diene rubber, and ethylene vinyl acetate.

9. In paragraph 1, The electrode assembly includes a first negative electrode collector, a first negative electrode, a first electrolyte, a first positive electrode, a positive electrode collector, a second positive electrode, a second electrolyte, a second negative electrode, and a second negative electrode collector, The above first compression pad is placed between one side of the first negative electrode collector and one side of the case, A secondary battery cell, wherein the second compression pad is disposed between one side of the second negative electrode collector and one side of the case.

10. In paragraph 9, A secondary battery cell, wherein the elastic modulus of the first compression pad and the second compression pad is 1.0 GPa to 5.0 GPa.

11. In paragraph 9, A secondary battery cell, wherein the thickness of the first compression pad and the second compression pad is 0.01 mm to 2.0 mm.

12. In paragraph 9, A secondary battery cell, wherein the thickness of the first compression pad and the second compression pad is 1 / 30 to 1 / 2 of the thickness of the battery cell.

13. In paragraph 9, The above electrode assembly comprises a plurality of electrode assemblies, A secondary battery cell further comprising an intermediate pad disposed between the electrode assemblies.

14. In paragraph 13, A secondary battery cell, wherein the elastic modulus of the above intermediate pad is 1.0 GPa to 3.0 GPa.

15. In paragraph 13, A secondary battery cell, wherein the thickness of the above intermediate pad is 0.01 mm to 0.3 mm.

16. In paragraph 13, A secondary battery cell, wherein the thickness of the intermediate pad is 1 / 30 to 1 / 3 of the thickness of the battery cell.

17. In paragraph 1, A secondary battery cell, wherein the electrolyte comprises a solid electrolyte.

18. In paragraph 17, A secondary battery cell, wherein the solid electrolyte comprises a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a polymer-based solid electrolyte.

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