Electrode for secondary battery, method for manufacturing the same, electrode assembly comprising the same, battery cell comprising the same

Abstract

According to exemplary embodiments of the present invention, a method for manufacturing an electrode for a secondary battery may be provided. The method for manufacturing an electrode for a secondary battery comprises the steps of: applying a first slurry on a first surface of a first sublayer; applying a second slurry on a first surface of a second sublayer; and bonding a second surface opposite to the first surface of the first sublayer and a second surface opposite to the first surface of the second sublayer, wherein the first slurry and the second slurry may be electrode slurries of the same type.

Description

Technology Field

[0001] The present invention relates to an electrode for a secondary battery, a method for manufacturing the same, an electrode assembly including the same, and a battery cell including the same. Background Technology

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as energy sources for various wireless devices such as handsets, laptops, and cordless vacuum cleaners. Recently, as the manufacturing cost per unit capacity of secondary batteries has decreased dramatically due to improved energy density and economies of scale, and as the driving range of BEVs (battery electric vehicles) has increased to a level equivalent to that of fuel vehicles, the primary use of secondary batteries is shifting from mobile devices to mobility.

[0003] The trend in the technological development of rechargeable batteries for mobility is the improvement of energy density and safety. The safety of rechargeable batteries is critical as it is directly linked to the lives of passengers. The safety of rechargeable batteries can be achieved through mechanical robustness, the reliability of electrical insulation, and the delay of heat transfer in the event of a thermal runaway event. The problem to be solved

[0004] The problem that the technical concept of the present invention aims to solve is to provide a method for manufacturing an electrode for a secondary battery with improved performance and reliability.

[0005] The problem that the technical concept of the present invention aims to solve is to provide an electrode for a secondary battery with improved performance and reliability.

[0006] The problem that the technical concept of the present invention aims to solve is to provide an electrode assembly with improved performance and reliability.

[0007] The problem that the technical concept of the present invention aims to solve is to provide a battery cell with improved performance and reliability. means of solving the problem

[0008] According to exemplary embodiments of the present invention for solving the above-described problem, a method for manufacturing an electrode for a secondary battery may be provided. The method for manufacturing an electrode for a secondary battery comprises the steps of: applying a first slurry on a first surface of a first sublayer; applying a second slurry on a first surface of a second sublayer; and bonding a second surface opposite to the first surface of the first sublayer to a second surface opposite to the first surface of the second sublayer, wherein the first slurry and the second slurry may be electrode slurries of the same type.

[0009] The step of applying the first slurry and the step of applying the second slurry can be performed using the same coater.

[0010] The step of applying the first slurry and the step of applying the second slurry can be performed simultaneously.

[0011] After the step of applying the first slurry and the step of applying the second slurry, and before the step of bonding, the method may further include the step of drying the first slurry; and the step of drying the second slurry.

[0012] The step of drying the first slurry and the step of drying the second slurry can be performed using the same oven.

[0013] The step of drying the first slurry and the step of drying the second slurry can be performed simultaneously.

[0014] The first slurry and the second slurry may each be an anode slurry containing an anode active material.

[0015] The first slurry and the second slurry may each be a cathode slurry containing a cathode active material.

[0016] The first slurry and the second slurry may not be applied on the second surface of the first sublayer and the second surface of the second sublayer.

[0017] The above bonding step may include the step of bringing the second surface of the first sublayer and the second surface of the first sublayer face each other.

[0018] According to exemplary embodiments of the present invention for solving the above-described problem, an electrode for a secondary battery may be provided. The electrode for a secondary battery comprises a first active material layer, a second active material layer, and a current collector between them, wherein the current collector comprises a first sub-layer in contact with the first active material layer; a second sub-layer in contact with the second active material layer; and an adhesive layer between the first sub-layer and the second sub-layer, and the first active material layer and the second active material layer may comprise the same type of electrode active material.

[0019] According to exemplary embodiments of the present invention for solving the above-described problem, an electrode assembly may be provided. The electrode assembly comprises a positive electrode, a negative electrode, and a separator between them. The positive electrode comprises a positive current collector, a first positive active material layer, and a second positive active material layer spaced apart from the first positive active material layer with the positive current collector in between. The positive current collector may comprise a first sub-layer on which the first positive active material layer is disposed, a second sub-layer on which the second positive active material layer is disposed, and an adhesive layer between the first sub-layer and the second sub-layer.

[0020] According to exemplary embodiments of the present invention for solving the above-described problem, an electrode assembly may be provided. The electrode assembly comprises an anode, a cathode, and a separator between them, wherein the cathode comprises a cathode current collector, a first cathode active material layer, and a second cathode active material layer spaced apart from the first cathode active material layer with the cathode current collector in between, and the cathode current collector may comprise a first sub-layer on which the first cathode active material layer is disposed, a second sub-layer on which the second cathode active material layer is disposed, and an adhesive layer between the first sub-layer and the second sub-layer. Effects of the invention

[0021] According to exemplary embodiments of the present invention, an electrode for a secondary battery can be manufactured by applying an electrode slurry onto two current collector layers and bonding them together. By doing so, an electrode for a secondary battery with improved uniformity can be manufactured.

[0022] According to exemplary embodiments of the present invention, a method for manufacturing an electrode for a secondary battery with improved performance and reliability can be provided.

[0023] According to exemplary embodiments of the present invention, an electrode for a secondary battery with improved performance and reliability can be provided.

[0024] According to exemplary embodiments of the present invention, an electrode assembly with improved performance and reliability can be provided.

[0025] According to exemplary embodiments of the present invention, a battery cell with improved performance and reliability can be provided.

[0026] The effects obtainable from the exemplary embodiments of the present invention are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure belong from the following description. That is, unintended effects resulting from the implementation of the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure. Brief explanation of the drawing

[0027] FIG. 1 is a flowchart illustrating a method for manufacturing an electrode for a secondary battery according to exemplary embodiments based on the technical concept of the present invention. FIG. 2 is a flowchart illustrating a method for manufacturing an electrode for a secondary battery according to exemplary embodiments based on the technical concept of the present invention. FIG. 3 is a drawing for explaining a method for manufacturing an electrode for a secondary battery according to exemplary embodiments based on the technical concept of the present invention. FIG. 4 is a drawing for explaining a method for manufacturing an electrode for a secondary battery according to exemplary embodiments based on the technical concept of the present invention. FIG. 5 is a drawing for explaining a method for manufacturing an electrode for a secondary battery according to exemplary embodiments based on the technical concept of the present invention. FIG. 6 is a drawing of an electrode for a secondary battery according to exemplary embodiments based on the technical concept of the present invention. FIG. 7 is a drawing of an electrode for a secondary battery according to exemplary embodiments based on the technical concept of the present invention. FIG. 8 is a drawing of an electrode assembly according to exemplary embodiments based on the technical concept of the present invention. FIG. 9 is a drawing of an electrode assembly according to exemplary embodiments based on the technical concept of the present invention. FIG. 10 is a drawing of an electrode assembly according to exemplary embodiments based on the technical concept of the present invention. FIG. 11 is an exploded perspective view of a battery cell including an electrode assembly according to exemplary embodiments of the technical concept of the present invention. Specific details for implementing the invention

[0028] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor can appropriately define the concepts of terms to best describe his invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention.

[0029] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0030] In addition, in describing the present invention, if it is determined that a detailed description of related known components or functions may obscure the essence of the invention, such detailed description is omitted.

[0031] Since embodiments of the present invention are provided to more fully explain the invention to those skilled in the art, the shapes and sizes of the components in the drawings may be exaggerated, omitted, or schematically depicted for clearer explanation. Accordingly, the size or proportion of each component does not entirely reflect the actual size or proportion.

[0033] (1st embodiment)

[0034] FIG. 1 is a flowchart for explaining a method (S100) for manufacturing an electrode for a secondary battery according to exemplary embodiments based on the technical concept of the present invention.

[0035] FIG. 2 is a flowchart for explaining a method (S100) for manufacturing an electrode for a secondary battery according to exemplary embodiments based on the technical concept of the present invention.

[0036] FIG. 3 is a drawing for explaining a method (S100) for manufacturing an electrode for a secondary battery according to exemplary embodiments based on the technical concept of the present invention.

[0037] FIG. 4 is a drawing for explaining a method (S100) for manufacturing an electrode for a secondary battery according to exemplary embodiments based on the technical concept of the present invention.

[0038] FIG. 5 is a drawing for explaining a method (S100) for manufacturing an electrode for a secondary battery according to exemplary embodiments based on the technical concept of the present invention.

[0040] Referring to FIGS. 1 to 5, a method (S100) for manufacturing an electrode for a secondary battery may be provided.

[0041] Specifically, a step (S110) of applying a first slurry on a first sublayer and applying a second slurry on a second sublayer may be provided.

[0042] As illustrated in FIG. 3, a first slurry (21) can be applied on a first sublayer (11). A second slurry (22) can be applied on a second sublayer (12). The first sublayer (11) and the second sublayer (12) may be current collector layers. The first slurry (21) and the second slurry (22) may be electrode slurries of the same type.

[0043] In the embodiments, a first slurry (21) may be applied on a first surface (11_1) of the first sublayer (11). A second slurry (22) may be applied on a first surface (12_1) of the second sublayer (12). The first slurry (21) may not be applied on a second surface (11_2) of the first sublayer (11). The second slurry (22) may not be applied on a second surface (11_2) of the first sublayer (11). The second surface (11_2) of the first sublayer (11) may be opposite to the first surface (11_1). The first surface (11_1) and the second surface (11_2) may intersect with a first direction (D1) and extend in a second direction (D2). The second slurry (22) may not be applied on the second surface (12_2) of the second sublayer (12). The first slurry (21) may not be applied on the second surface (12_2) of the second sublayer (12). The second surface (12_2) of the second sublayer (12) may be opposite to the first surface (12_1). The first surface (12_1) and the second surface (12_2) may intersect the first direction (D1) and extend into the second direction (D2).

[0044] In the embodiments, applying the first slurry (21) on the first sublayer (11) and applying the second slurry (22) on the second sublayer (12) may be performed simultaneously. Applying the first slurry (21) on the first sublayer (11) and applying the second slurry (22) on the second sublayer (12) may be performed using the same coater. For example, the first slurry (21) and the second slurry (22) may be applied simultaneously using the same coater. Applying the first slurry (21) on the first sublayer (11) and applying the second slurry (22) on the second sublayer (12) may each involve applying the same amount of electrode slurry.

[0045] In one embodiment, the first slurry (21) and the second slurry (22) may be positive slurries. Both the first slurry (21) and the second slurry (22) may contain positive active materials. In this case, the first sublayer (11) and the second sublayer (12) may each be positive current collectors.

[0046] In another embodiment, the first slurry (21) and the second slurry (22) may be cathode slurries. Both the first slurry (21) and the second slurry (22) may contain a cathode active material. In this case, the first sublayer (11) and the second sublayer (12) may each be a cathode current collector layer.

[0048] Next, a step (S120) of drying the first slurry and the second slurry may be provided.

[0049] As illustrated in FIG. 4, a first active material layer (31) can be formed by drying a first slurry (21) on a first sub-layer (11). A second active material layer (32) can be formed by drying a second slurry (22) on a second sub-layer (12).

[0050] In the embodiments, drying the first slurry (21) on the first sublayer (11) and drying the second slurry (22) on the second sublayer (12) can be performed simultaneously. Drying the first slurry (21) on the first sublayer (11) and drying the second slurry (22) on the second sublayer (12) can be performed using the same oven. For example, the first slurry (21) and the second slurry (22) can be dried simultaneously using the same oven.

[0052] Next, a step (S130) of bonding the first sublayer and the second sublayer may be provided.

[0053] As illustrated in FIG. 5, the first sublayer (11) and the second sublayer (12) can be bonded by an adhesive layer (13) disposed between the first sublayer (11) and the second sublayer (12).

[0054] Specifically, referring to FIG. 2, a step (S131) ​​of bringing the adhesive surfaces of the first sublayer (11) and the second sublayer (12) respectively to face each other can be performed to bond the first sublayer (11) and the second sublayer (12). As described above, an electrode slurry may be applied to the first surface of each of the first sublayer (11) and the second sublayer (12), and the electrode slurry may not be applied to the second surface. The second surface of each of the first sublayer (11) and the second sublayer (12) may be an adhesive surface. For example, the second surface (11_2) of the first sublayer (11) and the second surface (12_2) of the second sublayer (12) may be adhesive surfaces. In step (S131), the second surface (11_2) of the first sublayer (11) and the second surface (12_2) of the second sublayer (12) may be brought to face each other.

[0055] Following step (S131), step (S132) of applying an adhesive to the bonding surfaces of the first sublayer (11) and the second sublayer (12) may be performed. For example, the adhesive may be applied to the second surface (11_2) of the first sublayer (11) and the second surface (12_2) of the second sublayer (12). In other embodiments, the adhesive may be applied to only one of the second surface (11_2) of the first sublayer (11) and the second surface (12_2) of the second sublayer (12). In other embodiments, after applying the adhesive to the second surface (11_2) of the first sublayer (11) and the second surface (12_2) of the second sublayer (12), the second surface (11_2) of the first sublayer (11) and the second surface (12_2) of the second sublayer (12) may be brought to face each other.

[0056] Following step (S132), the adhesive surfaces of the first sub-layer (11) and the second sub-layer (12) can be bonded together. By doing so, an adhesive layer can be formed between the first sub-layer (11) and the second sub-layer (12) as illustrated in FIG. 5. For example, an adhesive layer (13) can be formed that is in direct contact with the second surface (11_2) of the first sub-layer (11) and the second surface (12_2) of the second sub-layer (12). By doing so, a current collector (10) composed of the first sub-layer (11), the adhesive layer (13), and the second sub-layer (12) arranged in the first direction (D1) can be formed.

[0058] A secondary battery electrode (10E) comprising a first active material layer (31), a second active material layer (32), and a current collector (10) between them can be manufactured by the method for manufacturing a secondary battery electrode (S100) described with reference to FIGS. 1 to 5.

[0059] According to the method for manufacturing an electrode for a secondary battery (S100) described with reference to FIGS. 1 to 5, an electrode slurry can be applied simultaneously to a first sub-layer (11) and a second sub-layer (12) using the same coater and dried simultaneously using the same oven. By doing so, non-uniformity and mismatch that may occur when the electrode slurry is applied sequentially to both sides of a current collector and dried can be improved. By the method for manufacturing an electrode for a secondary battery (S100), an electrode for a secondary battery with improved uniformity can be manufactured.

[0060] According to embodiments based on the technical concept of the present invention, a method (S100) for manufacturing an electrode for a secondary battery with improved performance and reliability can be provided.

[0062] (2nd Example)

[0063] FIG. 6 is a drawing of an electrode (110A) for a secondary battery according to exemplary embodiments based on the technical concept of the present invention.

[0064] Referring to FIG. 6, the electrode (110A) for the secondary battery may be a positive electrode.

[0065] In the embodiments, the electrode (110A) for a secondary battery may include a first positive active material layer (111A), a second positive active material layer (112A), and a positive current collector (113A) between them. The first positive active material layer (111A), the second positive active material layer (112A), and the positive current collector (113A) may be arranged in a first direction (D1). The first positive active material layer (111A) and the second positive active material layer (112A) may each include a positive active material, a conductive material, and a binder.

[0066] In the embodiments, the positive current collector (113A) may include a first sublayer (113_S1), a second sublayer (113_S2), and an adhesive layer (113_AL) between them. The first sublayer (113_S1), the second sublayer (113_S2), and the adhesive layer (113_AL) may be arranged in a first direction (D1). A first positive active material layer (111A) may be disposed on the first sublayer (113_S1). The first sublayer (113_S1) may be in direct contact with the first positive active material layer (111A). A second positive active material layer (112A) may be disposed on the second sublayer (113_S2). The second sublayer (113_S2) may be in direct contact with the second positive active material layer (112A).

[0067] The thickness of the positive current collector (113A) may be in the range from about 3 μm to about 500 μm. The positive current collector (113A) may not cause chemical changes in the secondary battery that is finally manufactured and may have high conductivity. For example, the first sublayer (113_S1) and / or the second sublayer (113_S2) of the positive current collector (113A) may each comprise any one of stainless steel, aluminum, nickel, titanium, calcined carbon, and aluminum. The first sublayer (113_S1) and / or the second sublayer (113_S2) of the positive current collector (113A) may each comprise stainless steel surface-treated with carbon, nickel, titanium, silver, etc. The surface of each of the first sublayer (113_S1) and / or second sublayer (113_S2) of the positive current collector (113A) may include a micro-irregular structure to increase the adhesion of the active material. The shape of each of the first sublayer (113_S1) and / or second sublayer (113_S2) of the positive current collector (113A) may include any one of a film, sheet, foil, net, porous material, foam, and nonwoven fabric.

[0068] The positive electrode active material is a material capable of causing an electrochemical reaction. The positive electrode active material may be a lithium transition metal oxide. The positive electrode active material may be, for example, a layered compound such as lithium cobalt oxide (LiCoO2) and lithium nickel oxide (LiNiO2) substituted with one or more transition metals; lithium manganese oxide substituted with one or more transition metals; or a material with the chemical formula LiNi 1-y M y Lithium nickel-based oxide represented by O2 (where M is any one of Co, Mn, Al, Cu, Fe, Mg, B, Cr, Zn, and Ga, and 0.01≤y≤0.7); Li 1+z Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O2, Li 1+zN i0.4 Mn 0.4 Co 0.2 Li like O2 1+z Ni b Mn c Co 1-(b+c+d) M d O (2-e) A e A lithium nickel cobalt manganese composite oxide represented by (where -0.5≤z≤0.5, 0.1≤b≤0.8, 0.1≤c≤0.8, 0≤d≤0.2, 0≤e≤0.2, b+c+d<1, M is any one of Al, Mg, Cr, Ti, Si and Y, and A is any one of F, P and Cl); and chemical formula Li 1+x M 1-y M' y PO 4-z X z It may include any one of the olivine-based lithium metal phosphates represented by (wherein M is a transition metal, more specifically one of Fe, Mn, Co and Ni, M' is one of Al, Mg and Ti, X is one of F, S and N, -0.5≤x≤+0.5, 0≤y≤0.5, and 0≤z≤0.1).

[0069] The conductive material can provide conductivity without causing chemical changes in the secondary battery ultimately manufactured. The conductive material may include, for example, graphite such as natural graphite or synthetic graphite; carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers or metal fibers; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskey such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; polyphenylene derivatives, etc.

[0070] The binder can enhance the bonding between the active material and the conductive material and the bonding strength to the electrode plate. The binder may include, for example, polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butylene rubber, fluororubber, various copolymers, etc.

[0071] According to embodiments based on the technical concept of the present invention, an electrode (110A) for a secondary battery with improved performance and reliability can be provided.

[0073] (3rd Example)

[0074] FIG. 7 is a drawing of an electrode (120A) for a secondary battery according to exemplary embodiments based on the technical concept of the present invention.

[0075] Referring to FIG. 7, the electrode (120A) for the secondary battery may be a negative electrode.

[0076] In the embodiments, the electrode (120A) for the secondary battery may include a first negative active material layer (121A), a second negative active material layer (122A), and a negative current collector (123A) between them. The first negative active material layer (121A), the second negative active material layer (122A), and the negative current collector (123A) may be arranged in a first direction (D1). The first negative active material layer (121A) and the second negative active material layer (122A) may each include a negative active material, a conductive material, and a binder.

[0077] In the embodiments, the negative current collector (123A) may include a first sublayer (123_S1), a second sublayer (123_S2), and an adhesive layer (123_AL) between them. The first sublayer (123_S1), the second sublayer (123_S2), and the adhesive layer (123_AL) may be arranged in a first direction (D1). A first negative active material layer (121A) may be disposed on the first sublayer (123_S1). The first sublayer (123_S1) may be in direct contact with the first negative active material layer (121A). A second negative active material layer (122A) may be disposed on the second sublayer (123_S2). The second sublayer (123_S2) may be in direct contact with the second negative active material layer (122A).

[0078] The thickness of the negative current collector (123A) may be in the range of about 3 μm to about 500 μm. The negative current collector may not cause chemical changes in the secondary battery that is finally manufactured and may have high conductivity. The negative current collector (123A) may comprise any one of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, and aluminum-cadmium alloy. Each of the first sublayer (123_S1) and / or second sublayer (123_S2) of the negative current collector (123A) may comprise stainless steel surface-treated with carbon, nickel, titanium, silver, etc. Each of the first sublayer (123_S1) and / or second sublayer (123_S2) of the negative current collector (123A) may include a micro-roughness structure to increase the adhesion of the active material. Each of the first sublayer (123_S1) and / or second sublayer (123_S2) of the negative current collector (123A) may include any one of a film, sheet, foil, net, porous material, foam, and nonwoven fabric.

[0079] The negative electrode active material may include carbon, for example, non-graphitizable carbon, graphite-based carbon, etc. The negative electrode active material is, for example, Li xFe2O3(0≤x≤1), LixWO2(0≤x≤1), Sn x Me 1-x Me y O z (wherein Me is any one of Mn, Fe, Pb, and Ge, and Me' is any one of Al, B, P, Si, Group 1, Group 2, and Group 3 elements of the periodic table, and halogens; 0 <x≤1 이고; 1≤y≤3 이며; 1≤z≤8) 등의 금속 복합 산화물을 포함할 수 있다. 음극 활물질은, 예컨대, 리튬 금속; 리튬 합금; 규소계 합금; 및 주석계 합금 중 어느 하나를 포함할 수 있다. 음극 활물질은, 예컨대, SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4및 Bi2O5등의 금속 산화물을 포함할 수 있다. 음극 활물질은, 예컨대, 폴리아세틸렌 등의 도전성 고분자; Li-Co-Ni 계 재료 등을 포함할 수도 있다.

[0080] According to embodiments based on the technical concept of the present invention, an electrode (120A) for a secondary battery with improved performance and reliability can be provided.

[0082] (Fourth Example)

[0083] FIG. 8 is a drawing of an electrode assembly (100_1) according to exemplary embodiments based on the technical concept of the present invention.

[0084] Referring to FIG. 8, the electrode assembly (100_1) may include a positive electrode (110A), a negative electrode (120), and a separator (130). The positive electrode (110A), the negative electrode (120), and the separator (130) may be stacked in a first direction (D1). The positive electrode (110A) may be the electrode (110A) for a secondary battery described with reference to FIG. 6. The negative electrode (120) may include a negative electrode current collector (123) and a negative electrode active material layer (122) on the negative electrode current collector (123).

[0085] In the embodiments, the positive electrode (110A) may include a positive electrode current collector (113A) and active material layers (111A, 112A) spaced apart therefrom. Specifically, the first positive electrode active material layer (111A) and the second positive electrode active material layer (112A) may be spaced apart with the positive electrode current collector (113A) in between. The first positive electrode active material layer (111A), the positive electrode current collector (113A), and the second positive electrode active material layer (112A) may be arranged in a first direction (D1).

[0086] Referring together with FIG. 6, the positive current collector (113A) may be composed of a first sublayer (113_S1), a second sublayer (113_S2), and an adhesive layer (113_AL). A first positive active material layer (111A) may be disposed on the first sublayer (113_S1). A second positive active material layer (112A) may be disposed on the second sublayer (113_S2). The first sublayer (113_S1) and the second sublayer (113_S2) may be bonded by the adhesive layer (113_AL) to form the positive current collector (113A).

[0087] As described above with reference to FIGS. 1 to 5, in order to form a positive electrode (110A) with a positive active material coated on both sides of a current collector (113A), a positive slurry is applied on each of the two sub-layers to form a positive active material layer (111A, 112A), and then the two layers can be bonded together.

[0088] Accordingly, the uniformity between the first positive active material layer (111A) and the second positive active material layer (112A) is improved, and an electrode assembly (100_1) with improved performance and reliability can be provided.

[0090] (5th Example)

[0091] FIG. 9 is a drawing of an electrode assembly (100_2) according to exemplary embodiments based on the technical concept of the present invention.

[0092] Referring to FIG. 9, the electrode assembly (100_2) may include a positive electrode (110), a negative electrode (120A), and a separator (130). The positive electrode (110), the negative electrode (120A), and the separator (130) may be stacked in a first direction (D1). The negative electrode (120A) may be the electrode (120A) for a secondary battery described with reference to FIG. 7. The positive electrode (110) may include a positive current collector (113) and a positive active material layer (111) on the positive current collector (113).

[0093] In the embodiments, the cathode (120A) may include a cathode current collector (123A) and active material layers (121A, 122A) spaced apart therefrom. Specifically, the first cathode active material layer (121A) and the second cathode active material layer (122A) may be spaced apart with the cathode current collector (123A) in between. The first cathode active material layer (121A), the cathode current collector (123A), and the second cathode active material layer (122A) may be arranged in a first direction (D1).

[0094] Referring to FIG. 7, the negative current collector (123A) may be composed of a first sublayer (123_S1), a second sublayer (123_S2), and an adhesive layer (123_AL). A first negative active material layer (121A) may be disposed on the first sublayer (123_S1). A second negative active material layer (122A) may be disposed on the second sublayer (123_S2). The first sublayer (123_S1) and the second sublayer (123_S2) may be bonded by the adhesive layer (123_AL) to form the negative current collector (123A).

[0095] As described above with reference to FIGS. 1 to 5, in order to form a negative electrode (120A) with a negative active material coated on both sides of a current collector (123A), a negative slurry is applied on each of the two sub-layers to form a negative active material layer (121A, 122A), and then the two layers can be bonded.

[0096] Accordingly, the uniformity between the first negative electrode active material layer (121A) and the second negative electrode active material layer (122A) is improved, and an electrode assembly (100_2) with improved performance and reliability can be provided.

[0098] (6th Example)

[0099] FIG. 10 is a drawing of an electrode assembly (100_3) according to exemplary embodiments of the technical concept of the present invention.

[0100] Referring to FIG. 10, the electrode assembly (100_3) may include a positive electrode (110A), a negative electrode (120A), and a separator (130). The positive electrode (110A), the negative electrode (120A), and the separator (130) may be stacked in a first direction (D1). The positive electrode (110A) may be the electrode (110A) for a secondary battery described with reference to FIG. 6. The negative electrode (120A) may be the electrode (120A) for a secondary battery described with reference to FIG. 7. The electrode assembly (110_3) may further include a negative electrode (120) spaced apart from the positive electrode (110A) with the separator (130) in between, and a positive electrode (110) spaced apart from the negative electrode (120A) with the separator (130) in between. The negative electrode (120) may include a negative electrode current collector (123) and a negative electrode active material layer (122) on the negative electrode current collector (123). The positive electrode (110) may include a positive electrode current collector (113) and a positive electrode active material layer (111) on the positive electrode current collector (113).

[0101] In the embodiments, the positive electrode (110A) may include a positive electrode current collector (113A) arranged in a first direction (D1) and active material layers (111A, 112A) spaced apart therefrom. Specifically, the positive electrode current collector (113A) may be composed of two sub-layers in which a first positive electrode active material layer (111A) and a second positive electrode active material layer (112A) are arranged and which are bonded by an adhesive layer.

[0102] In the embodiments, the cathode (120A) may include a cathode current collector (123A) positioned in a first direction (D1) and active material layers (121A, 122A) spaced apart therefrom. Specifically, the cathode current collector (123A) may be composed of two sub-layers in which a first cathode active material layer (121A) and a second cathode active material layer (122A) are positioned and bonded by an adhesive layer.

[0103] By doing so, an electrode assembly (100_3) with improved performance and reliability can be provided.

[0105] (7th Example)

[0106] FIG. 11 is an exploded perspective view of a battery cell (121) including an electrode assembly according to exemplary embodiments of the technical concept of the present invention.

[0107] Referring to FIG. 11, the battery cell (121) may include a case (121C), an electrode assembly (100), a positive terminal (121P), and a negative terminal (121N). The battery cell (121) may further include an electrolyte.

[0108] According to exemplary embodiments, the battery cell (121) may include one of a cylindrical secondary battery, a prismatic secondary battery, and a pouch-type secondary battery. The electrode assembly of the cylindrical secondary battery is embedded in a cylindrical metal can. The electrode assembly of the prismatic secondary battery is embedded in a prismatic metal can. The electrode assembly of the pouch-type secondary battery is embedded in a pouch case comprising an aluminum laminate sheet. Hereinafter, the technical concept of the present invention is described based on an example in which the battery cell (121) includes a pouch-type secondary battery, but a person skilled in the art will be able to easily arrive at an example in which the battery cell (121) includes one of a cylindrical secondary battery and a prismatic secondary battery based on what is described herein.

[0109] The electrode assembly (100) may include an electrode assembly for a secondary battery (100_1, 100_2, or 100_3) described with reference to FIGS. 8 to 10. For example, the electrode assembly (100) may include a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. The electrode assembly (100) may include an electrode for a secondary battery (110A) described with reference to FIG. 6. The electrode assembly (100) may include an electrode for a secondary battery (120A) described with reference to FIG. 7. The electrode of the electrode assembly (100) may be manufactured by the method for manufacturing an electrode for a secondary battery (S100) described with reference to FIGS. 1 to 5.

[0110] The electrode assembly (100) may be either a jelly-roll type or a stack type. The jelly-roll type electrode assembly (100) may include a wound structure of an anode, a cathode, and a separator interposed between them. The stack type electrode assembly (100) may include a plurality of anodes, a plurality of cathodes, and a plurality of separators interposed between them that are sequentially stacked.

[0111] In a stack-type electrode assembly (100), a plurality of positive electrodes and a plurality of negative electrodes may be arranged in a first direction (D1). In a stack-type electrode assembly (100), a plurality of positive electrodes and a plurality of negative electrodes may be stacked in a first direction (D1).

[0112] Each of the plurality of positives of the electrode assembly (100) may include a positive tab (not shown). Each positive tab of the plurality of positives of the electrode assembly (100) may be short-circuited with a positive terminal (121P). Each positive tab of the plurality of positives of the electrode assembly (100) may be welded with a positive terminal (121P).

[0113] Each of the plurality of cathodes of the electrode assembly (100) may include a cathode tab (121NT). Each of the cathode tabs (121NT) of the plurality of cathodes of the electrode assembly (100) may be short-circuited with a cathode terminal (121N). Each of the cathode tabs (121NT) of the plurality of cathodes of the electrode assembly (100) may be welded with a cathode terminal (121N).

[0114] The case (121C) may include an inner resin layer, a metal layer, and an outer resin layer. An adhesive and an anti-corrosion layer may be further provided between the inner resin layer and the metal layer and between the outer resin layer and the metal layer.

[0115] The inner resin layer may have heat-sealability and may be referred to as a sealant layer. The inner resin layer enables sealing of the case (121C). The inner resin layer may include polyolefin-based resins such as polypropylene (PP) and polyethylene (PE), for example. The metal layer may include any one of an alloy of iron, carbon, chromium, and manganese, an alloy of iron, chromium, and nickel, and aluminum. The metal layer may be a gas barrier. The metal layer may block the entry and exit of gas through the case (121C). The outer resin layer may be a surface protection layer. The outer resin layer may include a material having wear resistance and heat resistance, such as nylon resin.

[0116] The case (121C) may be provided by joining the first case (121C1) and the second case (121C2). In this example, the first case (121C1) may be substantially flat. The first case (121C1) may not include a receiving portion. The second case (121C2) may include a receiving portion (121R). The terrace (121T) of the second case (121C2) may surround the receiving portion (121R).

[0117] An insulating tape (121I) may be applied to the positive terminal (121P) and the negative terminal (121N). The positive terminal (121P) and the negative terminal (121N) may protrude outside the case (121C). The positive terminal (121P) and the negative terminal (121N) may protrude from the case (121C) in a second direction (D2). Accordingly, the resulting voltage and current of the battery cell (121) may be output through the positive terminal (121P) and the negative terminal (121N). The positive terminal (121P) may be a positive lead. The negative terminal (121N) may be a negative lead.

[0118] The positive terminal (121P) and the negative terminal (121N) may be spaced apart in a second direction (D2). The second direction (D2) may be substantially parallel to each of the plurality of positives of the electrode assembly (100) and each of the plurality of negatives of the electrode assembly (100).

[0119] According to embodiments of the technical concept of the present invention, the uniformity of the active material layer can be improved, and thereby a battery cell (121) with improved performance and reliability can be provided.

[0121] The present invention has been described in more detail above through drawings and embodiments. However, the configurations described in the drawings or embodiments described in this specification are merely one embodiment of the present invention and do not represent all technical concepts of the present invention; therefore, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application. Explanation of the symbols

[0122] 11: 1st sub-layer 12: Second sub-layer 13: Adhesive layer 21: 1st slurry 22: Second slurry 31: First active material layer 32: Second active material layer 100, 100_1, 100_2, 100_3: Electrode assembly 121: Battery cell 110, 110A: Anode 111A: First positive active material layer 112A: Second positive active material layer 113A: Positive current collector 120, 120A: Cathode 121A: First negative electrode active material layer 122A: Second negative electrode active material layer 123A: Cathode current collector 130: Separator

Claims

Claim 1 A method for manufacturing an electrode for a secondary battery, comprising: a step of applying a first slurry on a first surface of a first sublayer; a step of applying a second slurry on a first surface of a second sublayer; and a step of bonding a second surface opposite to the first surface of the first sublayer and a second surface opposite to the first surface of the second sublayer, wherein the first slurry and the second slurry are electrode slurries of the same type. Claim 2 A method for manufacturing an electrode for a secondary battery according to claim 1, characterized in that the step of applying the first slurry and the step of applying the second slurry are performed using the same coater. Claim 3 A method for manufacturing an electrode for a secondary battery according to claim 1, characterized in that the step of applying the first slurry and the step of applying the second slurry are performed simultaneously. Claim 4 A method for manufacturing an electrode for a secondary battery according to claim 1, further comprising: a step of drying the first slurry after the step of applying the first slurry and the step of applying the second slurry, and before the step of bonding; and a step of drying the second slurry. Claim 5 A method for manufacturing an electrode for a secondary battery according to claim 4, characterized in that the step of drying the first slurry and the step of drying the second slurry are performed using the same oven. Claim 6 A method for manufacturing an electrode for a secondary battery according to claim 4, characterized in that the step of drying the first slurry and the step of drying the second slurry are performed simultaneously. Claim 7 A method for manufacturing an electrode for a secondary battery according to claim 1, wherein the first slurry and the second slurry are each a positive slurry containing a positive active material. Claim 8 A method for manufacturing an electrode for a secondary battery according to claim 1, wherein the first slurry and the second slurry are each a negative electrode slurry containing a negative electrode active material. Claim 9 A method for manufacturing an electrode for a secondary battery according to claim 1, characterized in that the first slurry and the second slurry are not applied on the second surface of the first sublayer and the second surface of the second sublayer. Claim 10 A method for manufacturing an electrode for a secondary battery according to claim 1, wherein the bonding step comprises the step of bringing the second surface of the first sublayer and the second surface of the first sublayer to face each other. Claim 11 An electrode for a secondary battery comprising a first active material layer, a second active material layer, and a current collector between them, wherein the current collector comprises a first sub-layer in contact with the first active material layer; a second sub-layer in contact with the second active material layer; and an adhesive layer between the first sub-layer and the second sub-layer, wherein the first active material layer and the second active material layer comprise the same type of electrode active material. Claim 12 An electrode assembly comprising an anode, a cathode, and a separator between them, wherein the anode comprises an anode current collector, a first anode active material layer, and a second anode active material layer spaced apart from the first anode active material layer with the anode current collector in between, and the anode current collector comprises a first sublayer on which the first anode active material layer is disposed, a second sublayer on which the second anode active material layer is disposed, and an adhesive layer between the first sublayer and the second sublayer. Claim 13 An electrode assembly comprising an anode, a cathode, and a separator between them, wherein the cathode comprises a cathode current collector, a first cathode active material layer, and a second cathode active material layer spaced apart from the first cathode active material layer with the cathode current collector in between, and the cathode current collector comprises a first sub-layer on which the first cathode active material layer is disposed, a second sub-layer on which the second cathode active material layer is disposed, and an adhesive layer between the first sub-layer and the second sub-layer.

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