Cathode for lithium secondary battery, and lithium secondary battery comprising same

Abstract

The present invention relates to a cathode for a lithium secondary battery and a lithium secondary battery comprising same and, more particularly, to a cathode for a lithium secondary battery and a lithium secondary battery comprising same, in which the cathode is formed such that the area of a cathode mixture layer is smaller than that of a cathode current collector.

Description

Anode for lithium secondary battery and lithium secondary battery containing same

[0001] The present invention relates to a positive electrode for a lithium secondary battery and a lithium secondary battery including the same, and more specifically, to a positive electrode for a lithium secondary battery configured such that the area of ​​the positive electrode mixture layer is smaller than that of the positive electrode current collector, and a lithium secondary battery including the same.

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0146522, dated October 30, 2023, the entire contents of which are incorporated herein by reference.

[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 through a process of 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 charge and discharge them to a predetermined voltage.

[0006] In the manufacture of pouch-type batteries, a process of applying high pressure to the battery cell under high temperature conditions may be included during the cell assembly process. In particular, the process of manufacturing an all-solid-state battery may include a Warm Isostatic Pressure (WIP) process by assembling a positive electrode and a positive electrode collector. At this time, when the isostatic pressure process is performed, the positive electrode mixture layer expands in the area direction, and the area of ​​the positive electrode mixture layer becomes larger than that of the positive electrode collector. The expanded area of ​​the positive electrode mixture layer protrudes beyond the perimeter of the positive electrode collector and curves along the surface of the positive electrode collector, which causes a problem in that cracks occur. When the generated crack is assembled with the negative electrode to manufacture a cell, a short circuit occurs, which causes a problem in that the performance of the battery cell is reduced.

[0007] Therefore, in order to achieve excellent performance of all-solid-state batteries, it is necessary to develop a cathode that prevents cracking of the electrode even after the isotropic pressing process.

[0008] [Previous literature]

[0009] (Patent Document 1) Republic of Korea Publication No. 10-2023-0084872 (June 13, 2023)

[0010] One of the objects of the present invention is to provide a positive electrode for a lithium secondary battery that prevents cracking of an electrode during a process of applying high temperature and high pressure during the manufacture of a lithium secondary battery.

[0011] Another object of the present invention is to provide a positive electrode for a lithium secondary battery that can prevent degradation of the performance and lifespan of a battery cell.

[0012] In one embodiment of the present invention, a positive electrode for a lithium secondary battery is provided, comprising a positive electrode current collector and a positive electrode mixture layer laminated on the positive electrode current collector, wherein the positive electrode mixture layer is configured to have a smaller area than the positive electrode current collector.

[0013] In one embodiment of the present invention, a positive electrode for a lithium secondary battery is provided, wherein the area of ​​the positive electrode mixture layer is a small area of ​​more than 0% and less than 30% of the area of ​​the positive electrode current collector.

[0014] In one embodiment of the present invention, a positive electrode for a lithium secondary battery is provided, wherein the positive electrode composite layer is arranged spaced inward from at least one periphery of the positive electrode current collector.

[0015] In one embodiment of the present invention, the positive electrode current collector provides a positive electrode for a lithium secondary battery including a laminated region where the positive electrode mixture layer is laminated and a surplus region where the positive electrode mixture layer is not laminated.

[0016] In one embodiment of the present invention, a positive electrode for a lithium secondary battery is provided, wherein the excess region is arranged along at least a portion of the periphery of the laminated region.

[0017] In one embodiment of the present invention, a positive electrode for a lithium secondary battery is provided, wherein the positive electrode current collector includes a first side on which a positive electrode terminal portion is arranged, a second side formed on the other side of the first side, and a third side and a fourth side connecting the first side and the second side, and the excess area is formed to include at least one side of the first side to the fourth side.

[0018] In one embodiment of the present invention, a positive electrode for a lithium secondary battery is provided in which the positive electrode mixture layer is arranged so that the center point of the positive electrode current collector and the center point of the positive electrode mixture layer are aligned.

[0019] In one embodiment of the present invention, the positive electrode mixture layer provides a positive electrode for a lithium secondary battery including a positive electrode active material, a conductive material, and a binder.

[0020] In one embodiment of the present invention, a positive electrode for a lithium secondary battery is provided, wherein the positive electrode current collector is any one metal selected from the group consisting of copper, aluminum, stainless steel, titanium, silver, palladium, nickel, alloys thereof, and combinations thereof.

[0021] In one embodiment of the present invention, a lithium secondary battery including the positive electrode, negative electrode, and solid electrolyte is provided.

[0022] The present invention can provide a positive electrode for a lithium secondary battery that prevents the occurrence of cracks in an electrode during a process of applying high temperature and high pressure during the manufacture of a lithium secondary battery.

[0023] Another object of the present invention is to provide a positive electrode for a lithium secondary battery that can prevent degradation of the performance and lifespan of a battery cell.

[0024] FIG. 1 and FIG. 2 are drawings showing a cathode assembly of a cathode for a lithium secondary battery according to one embodiment of the present invention.

[0025] FIG. 3 is a drawing showing a positive electrode for a lithium secondary battery according to one embodiment of the present invention.

[0026] FIGS. 4 to 7 are drawings showing the arrangement of a positive electrode mixture layer in a positive electrode for a lithium secondary battery according to one embodiment of the present invention.

[0027] 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.

[0028] 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.

[0029]

[0030] The manufacturing process of lithium secondary batteries, particularly the manufacturing process of all-solid-state batteries, may include a warm isostatic pressing (WIP) process. In the conventional manufacturing of positive electrodes, when the areas of the positive electrode mixture layer and the positive electrode collector are the same and the positive electrode mixture layer and the positive electrode collector are subjected to the warm isostatic pressing process, the positive electrode mixture layer increases in the area direction, and the area of ​​the positive electrode mixture layer becomes larger than the area of ​​the positive electrode collector. The enlarged area of ​​the positive electrode mixture layer protrudes beyond the perimeter of the positive electrode collector and curves along the surface of the positive electrode collector, which causes a problem in that cracks occur. When the generated crack is assembled with the negative electrode to manufacture a cell, a short circuit may occur, which may lead to a decrease in the performance and lifespan of the battery cell.

[0031] To solve these problems, the inventors of the present invention have completed a positive electrode for a lithium secondary battery that can prevent cracking of the positive electrode even after a high-temperature and high-pressure process.

[0032]

[0033] Referring to the drawings below, before going into a detailed description of the configuration of a positive electrode for a lithium secondary battery according to one embodiment of the present invention, the positive electrode assembly of the positive electrode for a lithium secondary battery will first be briefly described.

[0034] FIG. 1 and FIG. 2 are drawings showing a cathode assembly of a cathode for a lithium secondary battery according to one embodiment of the present invention.

[0035] The above-mentioned positive electrode for a lithium secondary battery may include a positive electrode current collector (100) and a positive electrode composite layer (200) laminated on the positive electrode current collector.

[0036] The above-described positive electrode current collector may further include a positive electrode terminal portion (110) on one side. In FIG. 1, the positive electrode terminal portion (110) is depicted as being connected to an end of one side of the positive electrode current collector, but is not limited thereto, and the position of the positive electrode terminal portion may be connected to any one position on one side of the positive electrode current collector.

[0037] The above positive electrode composite layer (200) can be laminated on one surface of the positive electrode current collector (100).

[0038] FIG. 3 is a drawing showing a positive electrode for a lithium secondary battery according to one embodiment of the present invention.

[0039] In one embodiment of the present invention, a positive electrode for a lithium secondary battery includes a positive electrode current collector and a positive electrode mixture layer laminated on the positive electrode current collector, and the positive electrode mixture layer may be configured to have a smaller area than the positive electrode current collector.

[0040] The area of ​​the positive electrode mixture layer may have a small area of ​​more than 0% to less than 30% of the area of ​​the positive electrode current collector. More specifically, the area of ​​the positive electrode mixture layer may be 0.1% to less than 30%, 0.5% to less than 30%, 1.0% to less than 30%, 1.5% to less than 30%, 2.0% to less than 30%, 2.5% to less than 30%, 3.0% to less than 30%, 3.5% to less than 30%, 4.0% to less than 30%, 4.5% to less than 30%, 5.0% to less than 30% of the area of ​​the positive electrode current collector.

[0041] 0.1% to 29.0% or less, 0.5% to 29.0% or less, 1.0% to 29.0% or less, 1.5% to 29.0% or less, 2.0% to 29.0% or less, 2.5% to 29.0% or less, 3.0% to 29.0% or less, 3.5% to 29.0% or less, 4.0% to 29.0% or less, 4.5% to 29.0% or less, 5.0% to 29.0% or less,

[0042] 0.1% to 28.0% or less, 0.5% to 28.0% or less, 1.0% to 28.0% or less, 1.5% to 28.0% or less, 2.0% to 28.0% or less, 2.5% to 28.0% or less, 3.0% to 28.0% or less, 3.5% to 28.0% or less, 4.0% to 28.0% or less, 4.5% to 28.0% or less, 5.0% to 28.0% or less,

[0043] 0.1% to 27.0% or less, 0.5% to 27.0% or less, 1.0% to 27.0% or less, 1.5% to 27.0% or less, 2.0% to 27.0% or less, 2.5% to 27.0% or less, 3.0% to 27.0% or less, 3.5% to 27.0% or less, 4.0% to 27.0% or less, 4.5% to 27.0% or less, 5.0% to 27.0% or less,

[0044] 0.1% to 26.0% or less, 0.5% to 26.0% or less, 1.0% to 26.0% or less, 1.5% to 26.0% or less, 2.0% to 26.0% or less, 2.5% to 26.0% or less, 3.0% to 26.0% or less, 3.5% to 26.0% or less, 4.0% to 26.0% or less, 4.5% to 26.0% or less, 5.0% to 26.0% or less,

[0045] 0.1% to 25.0% or less, 0.5% to 25.0% or less, 1.0% to 25.0% or less, 1.5% to 25.0% or less, 2.0% to 25.0% or less, 2.5% to 25.0% or less, 3.0% to 25.0% or less, 3.5% to 25.0% or less, 4.0% to 25.0% or less, 4.5% to 25.0% or less, 5.0% to 25.0% or less,

[0046] 0.1% to 24.0% or less, 0.5% to 24.0% or less, 1.0% to 24.0% or less, 1.5% to 24.0% or less, 2.0% to 24.0% or less, 2.5% to 24.0% or less, 3.0% to 24.0% or less, 3.5% to 24.0% or less, 4.0% to 24.0% or less, 4.5% to 24.0% or less, 5.0% to 24.0% or less,

[0047] 0.1% to 23.0% or less, 0.5% to 23.0% or less, 1.0% to 23.0% or less, 1.5% to 23.0% or less, 2.0% to 23.0% or less, 2.5% to 23.0% or less, 3.0% to 23.0% or less, 3.5% to 23.0% or less, 4.0% to 23.0% or less, 4.5% to 23.0% or less, 5.0% to 23.0% or less,

[0048] It may have a small area of ​​0.1% to 22.0% or less, 0.5% to 22.0% or less, 1.0% to 22.0% or less, 1.5% to 22.0% or less, 2.0% to 22.0% or less, 2.5% to 22.0% or less, 3.0% to 22.0% or less, 3.5% to 22.0% or less, 4.0% to 22.0% or less, 4.5% to 22.0% or less, 5.0% to 22.0% or less, but is not limited to these ranges.

[0049] In one embodiment of the present invention, a positive electrode for a lithium secondary battery may have a positive electrode composite layer arranged inwardly from at least one circumference of the positive electrode current collector.

[0050] In one embodiment of the present invention, the positive electrode current collector may include a laminated region (300) where the positive electrode mixture layer is laminated and a surplus region (400) where the positive electrode mixture layer is not laminated.

[0051] The above surplus area (400) may be arranged along at least a portion of the perimeter of the above laminated area (300).

[0052] The above-described positive electrode collector includes a first side on which a positive electrode terminal portion is arranged, a second side formed on the other side of the first side, a third side connecting the first side and the second side, and a fourth side, and the surplus area can be formed to include at least one side among the first side to the fourth side.

[0053] FIGS. 4 to 7 are drawings showing the arrangement of a positive electrode mixture layer in a positive electrode for a lithium secondary battery according to one embodiment of the present invention.

[0054] The above-described positive electrode collector may include a first excess area (410) formed to include a first side on which a positive electrode terminal portion (110) is arranged.

[0055] The above-described positive electrode collector may include a second excess region (420) formed to include a second side formed on the other side of the first side.

[0056] The above-described positive electrode collector may include a third excess region (430) formed to include a third side connecting the first side and the second side.

[0057] The above-described positive electrode collector may include a fourth excess region (440) formed to connect the first side and the second side and include a fourth side formed on the other side of the third side.

[0058] The above surplus area (400) may include at least one of a first surplus area (410), a second surplus area (420), a third surplus area (430), and a fourth surplus area (440).

[0059] In one embodiment of the present invention, the surplus area (400) may include any one of a first surplus area (410), a second surplus area (420), a third surplus area (430), and a fourth surplus area (440).

[0060] Although not illustrated, in one embodiment of the present invention, the surplus area (400) may include two surplus areas. For example, the surplus area (400) may include a first surplus area (410) and a second surplus area (420); a first surplus area (410) and a third surplus area (430); a first surplus area (410) and a fourth surplus area (440); a second surplus area (420) and a third surplus area (430); a second surplus area (420) and a fourth surplus area (440); or a third surplus area (430) and a fourth surplus area (440).

[0061] Although not illustrated, in one embodiment of the present invention, the surplus area (400) may include three surplus areas. For example, the surplus area (400) may include a first surplus area (410), a second surplus area (420), and a third surplus area (430); a first surplus area (410), a second surplus area (420), and a fourth surplus area (440); a first surplus area (410), a third surplus area (430), and a fourth surplus area (440); or a second surplus area (420), a third surplus area (430), and a fourth surplus area (440).

[0062] Although not illustrated, in one embodiment of the present invention, the surplus area (400) may include four surplus areas. That is, the surplus area (400) may include a first surplus area (410), a second surplus area (420), a third surplus area (430), and a fourth surplus area (440).

[0063] In one embodiment of the present invention, the positive electrode mixture layer may be arranged so that the center point of the positive electrode current collector and the center point of the positive electrode mixture layer are aligned.

[0064] In one embodiment of the present invention, the positive electrode composite layer may include a positive electrode current collector and a positive electrode active material applied to one or both sides of the positive electrode current collector.

[0065] The above positive electrode current collector is intended to support the positive electrode active material, and is not particularly limited as long as it has excellent conductivity and is electrochemically stable in the voltage range of the lithium secondary battery. For example, the positive electrode current collector may be any one metal selected from the group consisting of copper, aluminum, stainless steel, titanium, silver, palladium, nickel, alloys thereof, and combinations thereof. The stainless steel may be surface-treated with carbon, nickel, titanium, or silver. As the alloy, an aluminum-cadmium alloy may be preferably used. In addition, calcined carbon, a non-conductive polymer surface-treated with a conductive material, or a conductive polymer may be used.

[0066] The above positive electrode current collector can form fine irregularities on its surface to strengthen the bonding strength with the positive electrode active material, and can be used in various forms such as a film, sheet, foil, mesh, net, porous body, foam, and non-woven fabric.

[0067] The above positive electrode active material may optionally include a conductive material and a binder.

[0068] The above positive electrode active material may vary depending on the type of all-solid-state battery. For example, the positive electrode active material may be a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with a transition metal of higher order; chemical formula Li 1+x Mn 2-x Lithium manganese oxides such as O4(0≤x≤0.33), LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5, Cu2V2O7; chemical formula LiNi 1-x M x Ni-site lithium nickel oxide represented by O2 (M = Co, Mn, Al, Cu, Fe, Mg, B or Ga; 0.01≤x≤0.3); chemical formula LiMn 2-x M x Lithium manganese composite oxides expressed as O2 (M = Co, Ni, Fe, Cr, Zn or Ta; 0.01≤x≤0.1) or Li2Mn3MO8 (M = Fe, Co, Ni, Cu or Zn); LiNi x Mn 2-x Lithium manganese composite oxides with spinel structure represented by O4; LiCoPO4; LiFePO4; Elemental sulfur (S8); Li2Sn(n=1), organosulfur compounds or carbon-sulfur polymers (C2S x )n: x=2.5 ~ 50, n=2) may include sulfur series compounds, but is not limited to these.

[0069] The above conductive material is a material that electrically connects the electrolyte and the positive electrode active material and serves as a path for electrons to move from the current collector to the positive electrode active material. Any material that does not cause chemical changes in a lithium secondary battery and has porosity and conductivity can be used without restriction.

[0070] For example, the conductive material may be a porous carbon-based material, such as carbon black, graphite, graphene, activated carbon, carbon fiber, etc.; metallic fibers such as metal mesh; metallic powders such as copper, silver, nickel, aluminum, etc.; or organic conductive materials such as polyphenylene derivatives. The conductive materials may be used alone or in combination.

[0071] Current commercially available products include acetylene black series (such as those from Chevron Chemical Company or Gulf Oil Company), Ketjen Black EC series (from Armak Company), Vulcan XC-72 (from Cabot Company), and Super P (from MMM). Examples include acetylene black, carbon black, and graphite.

[0072] In addition, the positive electrode composite layer may additionally include a binder, and the binder increases the bonding strength between the components constituting the positive electrode composite layer and between them and the current collector, and any binder known in the art may be used.

[0073] For example, the binder may be a fluororesin binder including polyvinylidene fluoride (PVdF) or polytetrafluoroethylene (PTFE); a rubber binder including styrene butadiene rubber (SBR), acrylonitrile-butidiene rubber, and styrene-isoprene rubber; a cellulose binder including carboxyl methyl cellulose (CMC), starch, hydroxy propyl cellulose, and regenerated cellulose; a polyalcohol binder; a polyolefin binder including polyethylene and polypropylene; a polyimide binder; a polyester binder; and a silane binder. One, two or more mixtures or copolymers selected from the group consisting of may be used.

[0074] In one embodiment of the present invention, a lithium secondary battery may include a positive electrode, a negative electrode, and a solid electrolyte interposed therebetween, and the positive electrode may be the positive electrode for a lithium secondary battery of the present invention described above.

[0075] The above-mentioned negative electrode may include a negative electrode current collector and a negative electrode active material positioned on the negative electrode current collector. In addition, the negative electrode, like the positive electrode, may include a conductive material and a binder as needed. In this case, the negative electrode current collector, conductive material, and binder are as described above.

[0076] The above negative electrode active material may be any material that can reversibly intercalate or deintercalate lithium ions (Li+), or any material that can reversibly form a lithium-containing compound by reacting with lithium ions.

[0077] The above solid electrolyte may include at least one selected from the group consisting of a sulfide-based solid electrolyte, a polymer-based solid electrolyte, and an oxide-based solid electrolyte, and preferably may include a sulfide-based solid electrolyte. The above solid electrolyte may be in the form of particles.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] Hereinafter, preferred examples are presented to help understand the present invention, but the following examples are only illustrative of the present invention, and it is obvious to those skilled in the art that various changes and modifications are possible within the scope and technical idea of ​​the present invention, and it is also natural that such changes and modifications fall within the scope of the appended patent claims.

[0082]

[0083] Example 1

[0084] An aluminum current collector was used as a positive electrode collector, and a 142 ㎛ thick positive electrode composite layer was laminated on the positive electrode collector. The positive electrode collector had an area of ​​400 ㎟ and the positive electrode composite layer had an area of ​​360 ㎟. The laminate was subjected to isostatic pressing (WIP) at 5000 bar and 80 ℃ to manufacture a positive electrode.

[0085] Example 2

[0086] The positive electrode was manufactured in the same manner as in Example 1, except that the area of ​​the positive electrode composite layer was 320 ㎟.

[0087] Comparative Example 1

[0088] A positive electrode was manufactured using the same method as in Example 1, except that the area of ​​the positive electrode collector was 400 ㎟ and the area of ​​the positive electrode composite layer was 400 ㎟.

[0089] Comparative Example 2

[0090] The positive electrode was manufactured in the same manner as in Example 1, except that the area of ​​the positive electrode composite layer was 280 ㎟.

[0091]

[0092] Experimental Example 1: Comparison of the length and area of ​​the anode composite layer before and after isotropic pressing.

[0093] The change in length or width of the positive electrode mixture layer in the positive electrode of Example 1 and Comparative Example 1 before and after isotropic pressing was measured. The results are shown in Table 1 below.

[0094] Isotropic pressurization Before Isotropic pressurization After length ratio (%) Area ratio (%) Length ratio (%) Area ratio (%) Example 1100100100.5101.1 Comparative example 1100100101.5103.0

[0095] As shown in Table 1 above, it was confirmed that the positive electrode mixture layer of the positive electrodes manufactured in Example 1 and Comparative Example 1 both increased after the isotropic pressing process. After isotropic pressing, the positive electrode mixture layer increased within the range of 0.1 to 2.0% compared to the length before isotropic pressing, and increased within the range of 1.0 to 4.0% compared to the area before isotropic pressing.

[0096] Experimental Example 2: Cell Performance Data According to Area Ratio

[0097] The area and capacity retention rate of the positive electrode mixture layer after isotropic pressing of the positive electrode mixture layer in Examples 1 and 2 and Comparative Examples 1 and 2 were measured. The results are shown in Table 2 below.

[0098] Area (㎟) of the positive electrode composite layer after isotropic pressing Capacity retention rate (%) Example 1364.0150 Example 2323.8150 Comparative example 1412.0100 Comparative example 2283.150

[0099] As shown in Table 2 above, in the case of Examples 1 and 2, where the area of ​​the positive electrode mixture layer was small, exceeding 0% and less than 30% of the area of ​​the positive electrode current collector, it was confirmed that the capacity retention rate was excellent. On the other hand, in the case of Comparative Examples 1 and 2, where the area of ​​the positive electrode mixture layer was the same as the area of ​​the positive electrode current collector or 30% smaller than the area of ​​the positive electrode current collector, it was confirmed that the capacity retention rate was significantly lower than in Examples 1 and 2.

[0100] While one embodiment of the present invention has been exemplified above, it is not intended to limit the scope of the present invention to the aforementioned embodiments. Those skilled in the art will be able to appropriately modify one embodiment of the present invention, including omitting, modifying, or replacing all or part of the configuration of the present invention, or adding other configurations, without departing from the technical spirit of the present invention, by referring to this specification and the attached drawings.

[0101]

[0102] The terms and expressions in this specification are to be interpreted broadly and not in a restrictive sense. As used herein, the word "comprises" does not exclude the presence or addition of one or more other components other than the components mentioned.

[0103] In this specification, expressions in the singular include the plural unless explicitly excluded by context.

[0104] Each of the embodiments exemplarily described herein can be combined with one another, and unless contradictory, the content described in a specific embodiment can be equally applied to other embodiments even if not described in the other embodiments.

[0105] [Explanation of symbols]

[0106] 100: Positive current collector

[0107] 110: Positive terminal

[0108] 200: Bipolar composite layer

[0109] 300: Stacking area

[0110] 400: Surplus area

[0111] 410: First Surplus Area

[0112] 420: Second Surplus Area

[0113] 430: Third Surplus Area

[0114] 440: Fourth Surplus Area

Claims

1. Bipolar collector; A positive electrode composite layer laminated on the positive electrode current collector; The above positive electrode composite layer is, A positive electrode for a lithium secondary battery, configured to have a smaller area than the positive electrode current collector.

2. In paragraph 1, A positive electrode for a lithium secondary battery, wherein the area of ​​the positive electrode composite layer has a small area of ​​more than 0% and less than 30% of the area of ​​the positive electrode current collector.

3. In paragraph 1, A positive electrode for a lithium secondary battery, wherein the positive electrode composite layer is arranged spaced inward from at least one periphery of the positive electrode current collector.

4. In paragraph 1, The above positive electrode collector, A laminated region where the above-mentioned positive electrode composite layer is laminated; and A positive electrode for a lithium secondary battery, comprising an excess area in which the positive electrode composite layer is not laminated.

5. In paragraph 4, The above surplus area is, A positive electrode for a lithium secondary battery, wherein the positive electrode is arranged along at least a portion of the periphery of the above-mentioned laminated region.

6. In paragraph 4, The above positive electrode collector, It includes a first side on which a positive terminal portion is arranged, a second side formed on the other side of the first side, and a third side and a fourth side connecting the first side and the second side, The above surplus area is, A positive electrode for a lithium secondary battery, formed to include at least one side among the first to fourth sides.

7. In paragraph 1, A positive electrode for a lithium secondary battery, wherein the positive electrode composite layer can be arranged so that the center point of the positive electrode current collector and the center point of the positive electrode composite layer are aligned.

8. In paragraph 1, A positive electrode for a lithium secondary battery, wherein the positive electrode composite layer comprises a positive electrode active material, a conductive material, and a binder.

9. In paragraph 1, A positive electrode for a lithium secondary battery, wherein the positive electrode current collector is any one metal selected from the group consisting of copper, aluminum, stainless steel, titanium, silver, palladium, nickel, alloys thereof, and combinations thereof.

10. A positive electrode for a lithium secondary battery according to any one of claims 1 to 9; cathode; and A lithium secondary battery comprising a solid electrolyte interposed between them.

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