KR102026292B1 - Electrode Assembly Comprising Electrode Having Gradient in Loading Amount of Active Material - Google Patents

Abstract

The present invention provides an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, wherein the positive electrode and the negative electrode includes an active material coating on one side or both sides of the plate-shaped current collector, at one end of the current collector The electrode tab is not coated with the electrode active material, and at least one electrode of the positive electrode and the negative electrode provides an electrode assembly, characterized in that the loading amount of the active material coating portion increases toward the electrode tab.

Description

Electrode Assembly Comprising Electrode Having Gradient in Loading Amount of Active Material}

The present invention relates to an electrode assembly, characterized in that at least one electrode of the positive electrode and the negative electrode is made of a structure in which a loading amount of the active material coating portion increases toward the electrode tab.

Due to the rapid increase in the use of fossil fuels, the demand for the use of alternative energy or clean energy is increasing. As a part of this, the most actively researched fields are power generation and storage using electrochemistry.

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

According to the shape of the battery case, secondary batteries are classified into cylindrical batteries and rectangular batteries in which the electrode assembly is embedded in a cylindrical or rectangular metal can, and pouch-type batteries in which the electrode assembly is embedded in a pouch type case of an aluminum laminate sheet. .

The electrode assembly embedded in the battery case is a power generator capable of charging and discharging composed of a laminated structure of a cathode, a separator, and a cathode, and has a jelly-roll type wound between a long sheet-type anode and an anode coated with an active material through a separator, A plurality of positive and negative electrodes of size are classified into a stack type in which a plurality of positive and negative electrodes are sequentially stacked in a state where a separator is interposed.

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

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, a lamination / stack type electrode having a structure in which electrode cells and separators are alternately stacked and laminated unit cells are laminated. Assembly was also developed.

These secondary batteries are attracting attention as a power source that requires high power, such as electric vehicle (EV), hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (Plug-In HEV), and in response to this trend, the specifications of the battery It is expanding.

In particular, in the case of a medium-large secondary battery requiring high output, a rectangular plate-shaped battery is mainly used in consideration of an internal space of a device in which the battery is mounted, and at this time, plate-type battery cells having an increased length to width are mainly used.

In general, in the manufacture of such a plate-shaped battery cell, the electrode active material is uniformly coated on the plate-shaped current collector, the electrode tab is not coated with the electrode active material is connected to the electrode lead. In the battery cell manufactured as described above, since active current flows in the electrode tab region having low resistance during charging and discharging, the electrode active material near the electrode tab is used more than the electrode active material far from the electrode tab. The biased use of the electrode active material causes premature degradation of the electrode, shortening the lifespan, and acting as a factor that inhibits stable output. As battery cells increase in capacity and energy density increases, this becomes a more serious problem.

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 that have been requested from the past.

After various experiments and in-depth studies, the inventors of the present application have developed an electrode assembly having a structure in which an amount of loading of an active material coating portion on a collector increases toward an electrode tab, and when using such an electrode assembly, a desired effect is obtained. It was confirmed that can be achieved, and came to complete the present invention.

Accordingly, the present invention, the electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, the positive electrode and the negative electrode includes an active material coating on one or both sides of the plate-shaped current collector, An electrode tab on which one electrode end is not coated is formed; At least one electrode of the positive electrode and the negative electrode has a structure in which the loading amount of the active material coating portion increases toward the electrode tab.

That is, the electrode assembly according to the present invention has a structure in which the loading amount of the active material coating portion is increased toward the electrode tab, thereby preventing the biased use of the electrode and partially deteriorating the electrode tab portion where the active current is moved. It can be minimized.

The electrode tab of the positive electrode and the electrode tab of the negative electrode may be formed at both ends of the electrode assembly facing each other. However, depending on the shape and manufacturing purpose of the battery case, the electrode tab of the positive electrode and the electrode tab of the negative electrode may be formed together at one end of the electrode assembly to face the same direction.

The loading amount of the active material may be variously controlled by the thickness and density of the coating. In one specific example, the density of the coating is the same at any position of the active material coating portion, the coating thickness may be formed differently depending on the loading amount. In such a structure, the coating thickness may be formed to be the same in the width direction of the current collector at any position relative to the electrode tab and to increase toward the electrode tab.

In this case, the coating thickness at the adjacent portion of the electrode tab, the output of the battery, when the operation of the battery cell, may be determined in consideration of the resistance generated by the flow of current in the electrode tab region, the volume of the battery, etc. It may range from 110% to 300%, specifically 130% to 200%, with respect to the coating thickness of the end portion.

If the thickness is less than 110% outside the above range, during the operation of the battery, the electrode active material is used more adjacent to the electrode tab than the electrode active material distant from the electrode tab may cause premature degradation of the electrode, 300 If it exceeds%, it is not preferable because the shape of the electrode assembly due to the excessive thickness difference is asymmetric and the manufacturing process may not be easy. Similarly, the width of the negative electrode terminal may be 1% to 10% of the winding length of the negative electrode.

In another specific example, the coating thickness is the same at any position of the active material coating portion, and may be formed to have a different coating density according to the loading amount, specifically, the coating density may be formed to increase toward the electrode tab.

In this case, the coating density at the adjacent portion of the electrode tab, may be determined in consideration of the output of the battery, the resistance generated by the flow of electrons to the electrode tab portion during operation of the battery cell, the volume of the battery, etc. It may range from 110% to 300%, specifically 130% to 200%, with respect to the coating density of the site.

Outside the above range, when the density is less than 110%, the electrode active material is used more in the adjacent region of the electrode tab than the electrode active material far from the electrode tab during operation of the battery cell may cause premature degradation of the electrode, If it exceeds 300%, there is a risk of explosion due to excessive resistance of electrons generated in the adjacent area of the electrode tab due to excessive density difference during operation of the battery cell, and there is a risk of explosion, and an additional process of compressing the active material to high density And costs are undesirable.

In another specific example, the electrode assembly may have the same loading amount at the same distance from the electrode tab, based on the electrode tab. In one example, the coating thickness or coating density according to the loading amount may be formed in a radial contour structure with respect to the electrode tab to increase or decrease. In the case of a high-output battery, as described above, the specification of the plate-shaped battery is expanded, so that partial premature degradation due to the biased use of the electrode occurring in the longitudinal direction of the plate-shaped battery also occurs in the width direction, so as to minimize such a problem. The coating thickness or coating density can vary with a radial contour structure with respect to the electrode tab.

In another specific example of the electrode assembly according to the present invention, each of the positive electrode and the negative electrode has a structure in which the loading amount of the active material coating portion increases toward the electrode tab, and the loading amount of the negative electrode active material coating portion at any position is the loading of the positive electrode active material coating portion. It may be formed equal to or greater than the amount. By such a structure, the possibility of the short circuit by lithium precipitation in a negative electrode can be minimized.

Other components contained 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, then drying and pressing, and optionally, a filler is further added to the mixture.

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

The positive electrode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with one or more transition metals; Lithium manganese oxides such as Li _{1 + x} Mn _2-x O ₄ , wherein 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 , Cu ₂ V ₂ O ₇ and the like; Ni-site type lithium nickel oxide represented by the 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; 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, Lithium manganese composite oxide represented by Ni, Cu or Zn); Spinel-structure lithium manganese composite oxides represented by LiNi _x Mn _2-x O ₄ ; LiMn ₂ O _{4 in} which a 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 typically added in an amount of 1 to 30 wt% based on the total weight of the mixture including the positive electrode active material. Such a conductive material is not particularly limited as long as it has conductivity without causing chemical change in the battery, and examples thereof include graphite such as natural graphite and artificial graphite; Carbon blacks 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 whiskeys such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is a component that assists the bonding of the active material and the conductive material to the current collector, and is generally added in an amount of 1 to 30 wt% based on the total weight of the mixture including the positive electrode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers and the like.

The filler is optionally used as a component for inhibiting expansion of the positive electrode, and is not particularly limited as long as it is a fibrous material without causing chemical change in the battery. Examples of the filler include olefinic polymers such as polyethylene and polypropylene; Fibrous materials, such as glass fiber and carbon fiber, are used.

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

The negative electrode current collector is generally made of a thickness of 3 ~ 500 ㎛. Such a negative electrode current collector is not particularly limited as long as it has conductivity without causing 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 and the like on the surface, aluminum-cadmium alloy and the like can be used. In addition, like the positive electrode current collector, fine concavities and convexities may be formed on the surface to enhance the bonding strength of the negative electrode active material, and may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric.

The negative electrode active material may be, for example, carbon such as hardly graphitized carbon or graphite 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' Metal complex oxides such as Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen, 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 metal oxides such as 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 from 0.01 to 10 ㎛ ㎛, thickness is generally 5 ~ 300 ㎛. As such a separator, for example, olefin polymers such as chemical resistance and hydrophobic polypropylene; Sheets or non-woven fabrics made of glass fibers 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 contained in the battery case together with the electrode assembly may be a lithium salt-containing nonaqueous electrolyte consisting of a nonaqueous electrolyte and a lithium salt. In this case, the nonaqueous electrolyte may include a non-aqueous organic solvent, an organic solid electrolyte, an inorganic solid electrolyte, and the like. 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-dioxorone, formamide, dimethylformamide, dioxolon , Acetonitrile, nitromethane, methyl formate, methyl acetate, phosphate triester, trimethoxy methane, dioxorone derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbo Aprotic organic solvents such as nate derivatives, tetrahydrofuran derivatives, ethers, methyl pyroionate and ethyl propionate can be used.

Examples of the organic solid electrolyte include polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, polyedgetion lysine, polyester sulfides, polyvinyl alcohols, polyvinylidene fluorides, Polymerizers containing ionic dissociating groups and the like can 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 , Nitrides, halides, sulfates and the like of Li, such as Li ₄ SiO ₄ -LiI-LiOH, Li ₃ PO ₄ -Li ₂ S-SiS ₂ , and the like, may be used.

The lithium salt is a good material to be dissolved 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, for the purpose of improving the charge and discharge characteristics, flame retardancy, etc., the electrolyte solution, for example, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, hexa phosphate triamide, Nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrroles, 2-methoxy ethanol, aluminum trichloride and the like may be added. have. In some cases, in order to impart nonflammability, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further included, and carbon dioxide gas may be further included to improve high temperature storage characteristics, and FEC (Fluoro-Ethylene) may be further included. Carbonate), PRS (Propene sultone) may be further included.

For example, lithium salts such as LiPF ₆ , LiClO ₄ , LiBF ₄ , LiN (SO ₂ CF ₃ ) _2, and the like 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 electrolyte solution.

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

In one specific example, the battery case is a cylindrical case, the positive electrode terminal may be directly connected to the cap assembly mounted on the open top of the cylindrical case, the negative electrode terminal may be a structure connected directly to the inner surface of the cylindrical case.

In another specific example, the battery case may be a rectangular case, and the positive electrode terminal and the negative electrode terminal may be directly connected to respective terminal connection portions of the top plate mounted on the open upper end of the cylindrical case.

In some cases, the battery case may be a pouch type case, and the positive electrode terminal and the negative electrode terminal may be directly connected to respective terminal connection portions of a protective circuit member mounted outside the pouch type 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 having a metal layer of Al.

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

Specific examples of such a device may include a mobile device, a wearable device, a power tool that is powered by an electric motor; Electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and the like; Electric motorcycles including electric bicycles (E-bikes) and electric scooters (E-scooters); Electric golf carts; It may be an energy storage system.

Method for manufacturing the device is well known in the art, the description is omitted herein.

As described above, it is confirmed that the electrode assembly according to the present invention can solve the imbalance in the use of the active material in the same electrode to prevent the biased use of the electrode, thereby achieving stable output and prolonging the battery life. Could

1 is a schematic diagram of an electrode assembly according to one embodiment of the present invention;
2 is a schematic view of an electrode assembly according to another embodiment of the present invention;
3 is a schematic view of an electrode assembly according to another embodiment of the present invention;
4 is a schematic diagram of a positive electrode according to another embodiment of the present invention.

Hereinafter, although described with reference to the drawings according to an embodiment of the present invention, this is for easier understanding of the present invention, the scope of the present invention is not limited thereto.

1 is a schematic diagram of an electrode assembly 100 according to an embodiment of the present invention.

Referring to FIG. 1, the electrode tab 113 of the positive electrode 110 and the electrode tab 123 of the negative electrode 120 are formed at both ends of the electrode assembly 100 to face each other. The positive electrode 110 includes a positive electrode active material coating part 112 on both sides of the plate-shaped current collector 111, the electrode tab 113 is not formed on the active material is coated on one end of the current collector 111. In addition, the coating density is the same at any position of the active material coating portion 112, the coating thickness is the width direction of the current collector 111 at any position relative to the electrode tab 113 (see FIG. 1, In the direction of interconnecting the front and back of the figure), and the coating thickness increases toward the electrode tab 113. Therefore, the loading amount of the positive electrode active material coating portion 112 increases toward the electrode tab 113.

Similarly, the negative electrode 120 includes negative electrode active material coating portions 122 on both sides of the plate-shaped current collector 121, and electrode tabs 123 on which one end of the current collector 121 is not coated with an active material are formed. . In addition, the coating density is the same at any position of the active material coating portion 122, the coating thickness is the same in the width direction of the current collector 121 at any position relative to the electrode tab 123, the coating thickness Increases toward electrode tab 123. Therefore, the loading amount of the negative electrode active material coating part 122 increases toward the electrode tab 123.

In addition, the thickness of the coating at adjacent portions of the electrode tabs 113, 123 ranges from 110% to 300% relative to the thickness of the coating at the opposite end.

2 is a schematic view of an electrode assembly 200 according to another embodiment of the present invention.

Referring to FIG. 2, the electrode tab 213 of the anode 210 and the electrode tab 223 of the cathode 220 are formed at both ends of the electrode assembly 200 to face each other. The positive electrode 210 includes a positive electrode active material coating part 212 on both sides of the plate-shaped current collector 211, and the electrode tab 213 is formed on one end of the current collector 211 without the active material coated. In addition, the coating thickness is the same at any position of the active material coating portion 212, the coating thickness is the same in the width direction of the current collector 211 at any position relative to the electrode tab 213, the coating density is Increases toward electrode tab 213. Therefore, the loading amount of the positive electrode active material coating portion 212 increases toward the electrode tab 213.

Similarly, the negative electrode 220 includes a negative electrode active material coating part 222 on both sides of the plate-shaped current collector 221, the electrode tab 223 is not formed in the active material is coated on one end of the current collector 221. . In addition, the coating thickness is the same at any position of the active material coating portion 222, the coating thickness is the same in the width direction of the current collector 221 at any position relative to the electrode tab 223, the coating density is Increases toward electrode tab 223. Therefore, the loading amount of the negative electrode active material coating portion 222 increases toward the electrode tab 223.

In addition, the density of the coating at adjacent portions of the electrode tabs 213 and 223 ranges from 110% to 300% relative to the thickness of the coating at the opposite end.

3 is a schematic view of an electrode assembly according to another embodiment of the present invention.

Referring to FIG. 3, the electrode tab 313 of the anode 310 and the electrode tab 323 of the cathode 320 are formed at both ends of the electrode assembly 300 to face each other. The positive electrode 310 includes a positive electrode active material coating 312 on both sides of the plate-shaped current collector 311, and an electrode tab 313 having no active material coated thereon is formed at one end of the current collector 311. In addition, the coating density is the same at any position of the active material coating portion 312, the coating thickness is the same in the width direction of the current collector 311 at any position based on the electrode tab 313_, the coating thickness It increases toward the electrode tab 313. Therefore, the loading amount of the positive electrode active material coating portion 312 increases toward the electrode tab 313.

Similarly, the negative electrode 320 includes a negative electrode active material coating part 322 on both sides of the plate-shaped current collector 321, the electrode tab 323 is not formed on one side of the current collector 321 is not coated with the active material. . In addition, the coating density is the same at any position of the active material coating portion 322, the coating thickness is the same in the width direction of the current collector 321 at any position relative to the electrode tab 323, the coating thickness is Increases toward electrode tab 323. Therefore, the loading amount of the negative electrode active material coating part 322 increases toward the electrode tab 323.

In addition, the thickness of the coating at the adjacent portions of the electrode tabs 313 and 323 is in the range of 110% to 300% with respect to the thickness of the coating at the opposite end, and the loading amount of the negative electrode active material coating portion 322 at any position is It is equal to or greater than the loading amount of the positive electrode active material coating portion 312.

As such, the configuration in which the loading amount of the negative electrode active material coating part is equal to or greater than the loading amount of the positive electrode active material coating part may be applied to the embodiment shown in FIG. 2.

4 is a schematic diagram of a positive electrode according to another embodiment of the present invention.

Referring to FIG. 4, the positive electrode 410 includes a positive electrode active material coating part 412 on both sides of a plate-shaped current collector, and an electrode tab 413 having no active material coated thereon is formed at one end of the current collector. In addition, with respect to the electrode tab 413, the loading amount is the same at the same distance from the electrode tab 413, and the coating thickness or the coating density according to the loading amount is the radial contour line 420 based on the electrode tab 413. 421, 422, 423, and 424 and increase in a gentle gradient toward the electrode tab 413. In addition, the loading amount of the adjacent portion of the electrode tab 413 corresponds to the range of 110% to 300% with respect to the loading amount of the opposite end portion.

As such, the coating thickness or coating density depending on the loading amount forms a radial contour structure with respect to the electrode tab and forms a gentle gradient toward the electrode tab, and the increasing structure is also applied to the cathode (not shown).

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

Claims (17)

In the electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, the structure of laminating them ,
The positive electrode and the negative electrode includes an active material coating on one or both sides of the plate-shaped current collector, the electrode tab is not coated on the electrode active material at one end of the current collector;
At least one of the positive electrode and the negative electrode has a structure in which the loading amount of the active material coating portion increases toward the electrode tab in a gentle radial contour structure at the same separation distance based on the electrode tab .
The loading amount of the negative electrode active material coating portion at any position is the same as or larger than the loading amount of the positive electrode active material coating portion,
The electrode assembly, characterized in that the coating thickness and / or coating density of the active material coating portion increases closer to the electrode tab side . The electrode assembly of claim 1, wherein the electrode tab of the positive electrode and the electrode tab of the negative electrode are formed at opposite ends of the electrode assembly, respectively. The electrode assembly of claim 1, wherein the electrode tab of the positive electrode and the electrode tab of the negative electrode face the same direction and are formed together at one end of the electrode assembly. The electrode assembly of claim 1, wherein the coating density is the same at any position of the active material coating part, and the coating thickness is different according to the loading amount. delete The electrode assembly of claim 4, wherein the coating thickness increases toward the electrode tab. 7. The electrode assembly of claim 6, wherein the coating thickness at adjacent portions of the electrode tab ranges from 110% to 300% relative to the coating thickness of the opposite end portion. 7. The electrode assembly of claim 6, wherein the coating thickness at adjacent portions of the electrode tab ranges from 130% to 200% relative to the coating thickness at the opposite end. The electrode assembly according to claim 1, wherein the coating thickness is the same at any position of the active material coating portion, and the coating density is different according to the loading amount. The electrode assembly of claim 9, wherein the coating density of the active material coating increases toward the electrode tab. 11. The electrode assembly of claim 10, wherein the coating density at adjacent portions of the electrode tab ranges from 110% to 300% relative to the coating density at the opposite end portion. 11. The electrode assembly of claim 10, wherein the coating density at adjacent portions of the electrode tab ranges from 130% to 200% relative to the coating density at the opposite end portion. delete delete delete The battery cell according to claim 1 or 1 2 , wherein the electrode assembly according to claim 1 is embedded in a battery case together with an electrolyte solution. A device comprising a battery cell according to claim 16 as a power source.

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