Positive electrode for secondary battery, electrode assembly for secondary battery comprising same, and secondary battery comprising same

Abstract

A positive electrode for a secondary battery according to exemplary embodiments of the present invention is provided. The positive electrode for a secondary battery comprises: a positive electrode current collector; a positive electrode active material layer on the positive electrode current collector; and a sacrificial positive electrode material, wherein the sacrificial positive electrode material may comprise a buried portion in the positive electrode current collector and a contact portion in contact with the positive electrode active material layer.

Description

A positive electrode for a secondary battery, an electrode assembly for a secondary battery including the same, and a secondary battery including the same

[0001] The present invention relates to a positive electrode for a secondary battery, an electrode assembly for a secondary battery including the same, and a secondary battery including the same. Specifically, the present invention relates to a positive electrode for a secondary battery including a sacrificial positive electrode material, an electrode assembly for a secondary battery including the same, and a secondary battery including the same.

[0002] This application claims the benefit of Korean application No. 10-2024-0132713, filed on September 30, 2024, which is incorporated herein by reference in its entirety.

[0003] 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.

[0004] 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.

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

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

[0008] According to exemplary embodiments of the present invention for solving the above-described problem, a positive electrode for a secondary battery is provided. The positive electrode for a secondary battery comprises a positive current collector; a positive active material layer on the positive current collector; and a sacrificial positive electrode material, wherein the sacrificial positive electrode material may include a buried portion within the positive current collector and a contact portion in contact with the positive active material layer.

[0009] The above positive current collector comprises a metal foil layer; and a carbon coating layer between the metal foil layer and the positive active material layer, and the buried portion of the sacrificial positive material may include a first portion surrounded by the carbon coating layer.

[0010] The buried portion of the sacrificial anode material may further include a second portion within the metal foil layer.

[0011] The contact portion of the sacrificial anode material may not be buried within the anode current collector.

[0012] The positive current collector and the positive active material layer are stacked in a first direction, the buried portion of the sacrificial positive material overlaps the positive current collector in a second direction intersecting the first direction, and the contact portion of the sacrificial positive material may not overlap the positive current collector in the second direction.

[0013] The above sacrificial cathode material can be configured to provide lithium ions to the above cathode active material layer.

[0014] The above positive active material layer comprises a positive active material, and the content ratio of the sacrificial positive material may be 1 wt% to 5 wt% of the positive active material.

[0015] According to exemplary embodiments of the present invention for solving the above-described problem, an electrode assembly for a secondary battery is provided. The electrode assembly for a secondary battery comprises: a negative electrode including a negative current collector and a negative active material layer on the negative current collector; a positive electrode including a positive current collector, a positive active material layer on the positive current collector, and a sacrificial positive electrode material; and a separator between the negative electrode and the positive electrode, wherein the sacrificial positive electrode material may include a buried portion within the positive current collector and a contact portion in contact with the positive active material layer.

[0016] The above positive current collector comprises a metal foil layer; and a carbon coating layer between the metal foil layer and the positive active material layer, and the buried portion of the sacrificial positive material may comprise a first portion surrounded by the carbon coating layer; and a second portion within the metal foil layer.

[0017] The above cathode, the above separator, and the above anode are stacked in a first direction, the buried portion of the sacrificial anode material overlaps the anode current collector in a second direction intersecting the first direction, and the contact portion of the sacrificial anode material may not overlap the anode current collector in the second direction.

[0018] The above sacrificial cathode material can be configured to provide lithium ions to the above cathode.

[0019] According to exemplary embodiments of the present invention, a cathode for a secondary battery may include a sacrificial cathode material. Accordingly, lithium ions (Li + Can supply ).

[0020] According to exemplary embodiments of the present invention, a positive electrode for a secondary battery with improved performance and reliability can be provided.

[0021] According to exemplary embodiments of the present invention, an electrode assembly for a secondary battery comprises a cathode for a secondary battery including a sacrificial cathode material, wherein lithium ions (Li) in a cathode active material layer+ It can supply ). Lithium ions (Li + ) can be delivered to the negative electrode for a secondary battery to increase the capacity of a secondary battery including an electrode assembly for a secondary battery.

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

[0023] According to exemplary embodiments of the present invention, a secondary battery may include a cathode comprising a sacrificial cathode material. The sacrificial cathode material comprises lithium ions (Li) in a cathode active material layer. + It supplies ), which is delivered to the negative electrode to increase the capacity of the secondary battery. In particular, during the initial charging phase of the secondary battery's activation, lithium ions (Li) are delivered to the negative electrode. + By providing ), the irreversible capacity of the negative electrode can be eliminated, thereby increasing the capacity of the secondary battery.

[0024] According to exemplary embodiments of the present invention, a secondary battery with improved performance and reliability can be provided.

[0025] 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.

[0026] FIG. 1 is a drawing of a positive electrode for a secondary battery according to embodiments of the technical concept of the present invention.

[0027] FIG. 2 is an enlarged view of a positive electrode for a secondary battery according to embodiments of the technical concept of the present invention.

[0028] FIG. 3 is a drawing for explaining a positive electrode for a secondary battery according to embodiments of the technical concept of the present invention.

[0029] FIG. 4 is a drawing of an electrode assembly for a secondary battery according to embodiments of the technical concept of the present invention.

[0030] FIG. 5 is a drawing for explaining an electrode assembly for a secondary battery according to embodiments of the technical concept of the present invention.

[0031] FIG. 6 is an exploded perspective view for explaining a secondary battery according to embodiments of the technical concept of the present invention.

[0032] 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, but should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0033] 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.

[0034] 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.

[0035] 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.

[0036]

[0037] (1st embodiment)

[0038] FIG. 1 is a drawing of a positive electrode (120) for a secondary battery according to embodiments of the technical concept of the present invention.

[0039] FIG. 2 is an enlarged view of a positive electrode (120) for a secondary battery according to embodiments of the technical concept of the present invention. Specifically, FIG. 2 is an enlarged view of the EX1 region of FIG. 1.

[0040] FIG. 3 is a drawing for explaining a positive electrode (120) for a secondary battery according to embodiments of the technical concept of the present invention.

[0041]

[0042] Referring to FIGS. 1 and 2, a positive electrode (120) for a secondary battery may include a positive electrode current collector (121) and a positive electrode active material layer (122). The positive electrode active material layer (122) may be disposed on the positive electrode current collector (121). The positive electrode active material layer (122) may be formed by coating a positive electrode active material on the positive electrode current collector (121). The positive electrode current collector (121) and the positive electrode active material layer (122) may be stacked in a first direction (X direction).

[0043] The positive current collector (121) may not cause chemical changes in the secondary battery that is finally manufactured and may have high conductivity. The positive current collector (121) may include, for example, any one of stainless steel, aluminum, nickel, titanium, calcined carbon, and aluminum. The positive current collector (121) may include stainless steel surface-treated with carbon, nickel, titanium, silver, etc. The surface of the positive current collector (121) may include a micro-irregular structure to increase the adhesion of the active material. The shape of the positive current collector (121) may include any one of a film, sheet, foil, net, porous material, foam, and non-woven fabric. The thickness of the positive current collector (121) may be in the range of about 3 μm to about 500 μm.

[0044] Specifically, the positive current collector (121) may include a metal foil layer (121_1) and a carbon coating layer (121_2). For example, the positive current collector (121) may include PCAF (Primer Coated Aluminum Foil). The positive current collector (121) may include a carbon-containing primer material coated on a metal foil. The metal foil layer (121_1) may include the metal foil, and the carbon coating layer (121_2) may include a coating layer of the carbon-containing primer material.

[0045] A carbon coating layer (121_2) may be disposed between a metal foil layer (121_1) and an anode active material layer (122). The carbon coating layer (121_2) may overlap the metal foil layer (121_1) in a first direction (X direction). The carbon coating layer (121_2) may contain carbon. The thickness of the carbon coating layer (121_2) may be smaller than the thickness of the metal foil layer (121_1). The thickness of the carbon coating layer (121_2) in the first direction (X direction) may be smaller than the thickness of the metal foil layer (121_1).

[0046] The positive active material layer (122) may include a positive active material. The positive active material is a material capable of causing an electrochemical reaction. The positive active material may be a lithium transition metal oxide. The positive 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 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 i 0.4 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 zIt 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).

[0047] The positive active material layer (122) may further include a conductive material and a binder.

[0048] 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.

[0049] 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.

[0050]

[0051] The cathode (120) for a secondary battery may further include a sacrificial cathode material (123). The sacrificial cathode material (123) may be embedded within the cathode (120) for a secondary battery. For example, the sacrificial cathode material (123) may include a portion embedded in the cathode current collector (121). The sacrificial cathode material (123) may come into contact with the cathode active material layer (122). The sacrificial cathode material (123) may include a portion in contact with the cathode active material layer (122).

[0052] Specifically, as illustrated in FIG. 2, the sacrificial cathode material (123) may include a buried portion (123B) embedded in the cathode current collector (121). For example, the buried portion (123B) may be surrounded by the cathode current collector (121). The buried portion (123B) may be surrounded by the cathode current collector (121) in a second direction (Y direction). The second direction (Y direction) may intersect with the first direction (X direction). The buried portion (123B) may be surrounded by the cathode current collector (121) in a third direction (Z direction). The third direction (Z direction) may intersect with the first direction (X direction) and the second direction (Y direction). The buried portion (123B) may overlap with the cathode current collector (121) in the first direction (X direction). The buried portion (123B) can overlap with the positive current collector (121) in the second direction (Y direction) and the third direction (Z direction).

[0053] The sacrificial cathode material (123) may include a portion surrounded by a carbon coating layer (121_2). For example, the buried portion (123B) may include a portion surrounded by a carbon coating layer (121_2). For example, the sacrificial cathode material (123) may include a first portion (123B_1) surrounded by a carbon coating layer (121_2). The first portion (123B_1) may be surrounded by the carbon coating layer (121_2) in a second direction (Y direction) and a third direction (Z direction). The first portion (123B_1) may overlap with the carbon coating layer (121_2) in the second direction (Y direction) and the third direction (Z direction).

[0054] The sacrificial cathode material (123) may include a portion embedded in the metal foil layer (121_1). For example, the embedded portion (123B) may include a portion embedded in the metal foil layer (121_1). For example, the embedded portion (123B) may include a second portion (123B_2) embedded in the metal foil layer (121_1). The second portion (123B_2) may be surrounded by the metal foil layer (121_1) in a second direction (Y direction) and a third direction (Z direction). The second portion (123B_2) may overlap the metal foil layer (121_1) in a first direction (X direction). The second portion (123B_2) may overlap the metal foil layer (121_1) in a second direction (Y direction) and a third direction (Z direction).

[0055] Specifically, the sacrificial cathode material (123) may include a contact portion (123C) that contacts the cathode active material layer (122). For example, the contact portion (123C) may be surrounded by the cathode active material layer (122). The contact portion (123C) may not be embedded within the cathode current collector (121). The contact portion (123C) may not overlap with the cathode current collector (121) in a second direction (Y direction) and a third direction (Z direction).

[0056] In the embodiments, the content ratio of the sacrificial cathode material (123) may be about 1 wt% to about 5 wt% of the cathode active material. For example, the content ratio of the sacrificial cathode material (123) may be about 1 wt% to about 5 wt% of the cathode active material in the cathode active material layer (122). For example, the content ratio of the sacrificial cathode material (123) may be about 3 wt% to about 5 wt% of the cathode active material in the cathode active material layer (122).

[0057]

[0058] Referring to FIG. 3, the sacrificial cathode material (123) is a lithium ion (Li) in the cathode active material layer (122). +) can be provided. The sacrificial cathode material (123) may contain lithium. For example, the sacrificial cathode material (123) may include LCO (Li-Co-O; lithium cobalt oxide), LNO (Li-Ni-O; lithium nickel oxide), LCZO (Li-Co-Zn-O; lithium cobalt zinc oxide), LCZAO (Li-Co-Zn-Al-O; lithium cobalt zinc aluminum oxide), L5F (Li5FeO4; lithium iron oxide) and / or LTFO (Li-Ti-Fe-O; lithium titanium iron oxide). The sacrificial cathode material (123) may provide lithium ions (Li) to the cathode active material layer (122) in contact with it. + Can supply ).

[0059] Unlike the embodiments according to the technical concept of the present invention, in a comparative example in which a sacrificial cathode material (123) is mixed or embedded within the positive active material layer (122), the sacrificial cathode material (123) contains lithium ions (Li) in the positive active material layer (122). + After supplying ) it acts as a resistor, and can increase the resistance of the positive active material layer (122). That is, in the embodiments according to the technical concept of the present invention, the resistance of the positive active material layer (122) can be reduced compared to the comparative example.

[0060]

[0061] The positive electrode (120) for a secondary battery described with reference to FIGS. 1 to 3 may include a sacrificial positive electrode material (123) embedded in a positive electrode current collector (121) and in contact with a positive electrode active material layer (122). Accordingly, lithium ions (Li + ) can be supplied, and the capacity of the battery including the positive electrode (120) for the secondary battery can be improved. That is, the performance and reliability of the positive electrode (120) for the secondary battery can be improved.

[0062] According to embodiments of the technical concept of the present invention, a positive electrode (120) for a secondary battery with improved performance and reliability can be provided.

[0063]

[0064] (2nd Example)

[0065] FIG. 4 is a drawing of an electrode assembly (100EA) for a secondary battery according to embodiments of the technical concept of the present invention.

[0066] FIG. 5 is a drawing for explaining an electrode assembly (100EA) for a secondary battery according to embodiments of the technical concept of the present invention.

[0067]

[0068]

[0069] Referring to FIG. 4, the electrode assembly (100EA) for a secondary battery may include a negative electrode (110) for a secondary battery, a positive electrode (120) for a secondary battery, and a separator (130). The positive electrode (120) for a secondary battery in FIG. 4 may be the positive electrode (120) for a secondary battery described with reference to FIG. 1 to FIG. 3.

[0070] The negative electrode (110) for the secondary battery, the positive electrode (120) for the secondary battery, and the separator (130) can be stacked in a first direction (X direction). The separator (130) can be placed between the negative electrode (110) for the secondary battery and the positive electrode (120) for the secondary battery.

[0071] The negative electrode (110) for a secondary battery may include a negative electrode current collector (111) and a negative electrode active material layer (112). The negative electrode active material layer (112) may be disposed on the negative electrode current collector (111). The negative electrode active material layer (112) may be a negative electrode active material coated on the negative electrode current collector (111). The negative electrode current collector (111) and the negative electrode active material layer (112) may be stacked in a first direction (X direction).

[0072] The negative current collector (111) may not cause chemical changes in the secondary battery that is finally manufactured and may have high conductivity. The negative current collector (111) may include any one of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, and aluminum-cadmium alloy. The negative current collector (111) may also include stainless steel surface-treated with carbon, nickel, titanium, silver, etc. The surface of the negative current collector (111) may include a micro-irregular structure to increase the adhesion of the active material. The shape of the negative current collector (111) may include any one of a film, sheet, foil, net, porous material, foam, and non-woven fabric. The thickness of the negative current collector (111) may be in the range of about 3 μm to about 500 μm.

[0073] The negative electrode active material layer (112) may include a negative electrode active material. 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 x Fe2O3(0≤x≤1), Li x WO2(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.

[0074] The negative electrode active material layer (112) may further include a conductive material and a binder. Regarding the conductive material and binder of the negative electrode active material layer (112), one may refer to the description regarding the conductive material and binder of the positive electrode active material layer (122) described with reference to FIGS. 1 to 3.

[0075]

[0076] Referring to FIG. 5, the sacrificial cathode material (123) is a lithium ion (Li) in the cathode active material layer (122). + ) can be provided. The sacrificial cathode material (123) can provide lithium ions (Li) to the cathode active material layer (122) in contact with it. + ) supplies, and lithium ions (Li + ) can pass through the separator (130) and be delivered to the negative electrode (110) for the secondary battery.

[0077]

[0078] The electrode assembly (100EA) for a secondary battery described with reference to FIGS. 4 and 5 may include a sacrificial cathode material (123) embedded in a positive current collector (121) and in contact with a positive active material layer (122). By doing so, lithium ions (Li) in the positive active material layer (122)+ It can supply ). Lithium ions (Li + ) can be delivered to the negative electrode (110) for the secondary battery to increase the capacity of the secondary battery including the electrode assembly (100EA) for the secondary battery. That is, the performance and reliability of the electrode assembly (100EA) for the secondary battery can be improved.

[0079] According to embodiments based on the technical concept of the present invention, an electrode assembly (100EA) for a secondary battery with improved performance and reliability can be provided.

[0080]

[0081] (3rd Example)

[0082] FIG. 6 is an exploded perspective view for explaining a secondary battery (100) according to embodiments of the technical concept of the present invention.

[0083] Referring to FIG. 6, the secondary battery (100) may include a case (100C), an electrode assembly (100EA), a positive terminal (100P), and a negative terminal (100N). The secondary battery (100) may further include an electrolyte.

[0084] According to exemplary embodiments, the secondary battery (100) 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 secondary battery (100) 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 secondary battery (100) includes one of a cylindrical secondary battery and a prismatic secondary battery based on what is described herein.

[0085] The electrode assembly (100EA) may include the electrode assembly (100EA) for a secondary battery described with reference to FIGS. 4 and 5. For example, the electrode assembly (100EA) may include a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. The electrode assembly (100EA) may include a positive electrode (120) for a secondary battery described with reference to FIGS. 1 to 3. For example, the electrode assembly (100EA) may include a positive electrode (120) for a secondary battery comprising a sacrificial positive electrode material (123) embedded in a positive current collector (121) and in contact with a positive active material layer (122).

[0086] The electrode assembly (100EA) may be either a jelly-roll type or a stack type. The jelly-roll type electrode assembly (100EA) may include a wound structure of an anode, a cathode, and a separator interposed between them. The stack type electrode assembly (100EA) may include a plurality of anodes, a plurality of cathodes, and a plurality of separators interposed between them that are sequentially stacked.

[0087] In a stack-type electrode assembly (100EA), a plurality of positive electrodes and a plurality of negative electrodes may be arranged in a first direction (X direction). In a stack-type electrode assembly (100EA), a plurality of positive electrodes and a plurality of negative electrodes may be stacked in a first direction (X direction).

[0088] Each of the plurality of positives of the electrode assembly (100EA) may include a positive tab (not shown). The positive tab of each of the plurality of positives of the electrode assembly (100EA) may be short-circuited with a positive terminal (100P). The positive tab of each of the plurality of positives of the electrode assembly (100EA) may be welded with a positive terminal (100P).

[0089] Each of the plurality of cathodes of the electrode assembly (100EA) may include a cathode tab (100NT). Each of the cathode tabs (100NT) of the plurality of cathodes of the electrode assembly (100EA) may be short-circuited with a cathode terminal (100N). Each of the cathode tabs (100NT) of the plurality of cathodes of the electrode assembly (100EA) may be welded with a cathode terminal (100N).

[0090] The case (100C) 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.

[0091] 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 (100C). The inner resin layer may include a polyolefin-based resin, 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 (100C). 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.

[0092] The case (100C) may be provided by joining a first case (100C1) and a second case (100C2). In this example, the first case (100C1) may be substantially flat. The first case (100C1) may not include a receiving portion. The second case (100C2) may include a receiving portion (100R). The receiving portion (100R) may be formed by a pouch forming process. The receiving portion (100R) is a part of the second case (100C2) formed into a bowl shape for receiving an electrode assembly (100EA).

[0093] The terrace (100T) of the second case (100C2) can surround the receiving portion (100R). The terrace (100T) of the second case (100C2) can be joined to the edge of the first case (100C1), and accordingly, the case (100C) can be provided.

[0094] An insulating tape (100I) may be applied to the positive terminal (100P) and the negative terminal (100N). The positive terminal (100P) and the negative terminal (100N) may protrude outside the case (100C). The positive terminal (100P) and the negative terminal (100N) may protrude from the case (100C) in a second direction (Y direction). Accordingly, the resulting voltage and current of the secondary battery (100) may be output through the positive terminal (100P) and the negative terminal (100N). The positive terminal (100P) may be a positive lead. The negative terminal (100N) may be a negative lead.

[0095] The positive terminal (100P) and the negative terminal (100N) may be spaced apart in a second direction (Y direction). The second direction (Y direction) may be substantially parallel to each of the plurality of positives of the electrode assembly (100EA) and each of the plurality of negatives of the electrode assembly (100EA).

[0096]

[0097] The secondary battery (100) described with reference to FIG. 6 may include a positive electrode (120) for a secondary battery comprising a sacrificial positive electrode material (123) embedded in a positive electrode current collector (121) and in contact with a positive electrode active material layer (122). As described with reference to FIG. 1 to 3, the sacrificial positive electrode material (123) contains lithium ions (Li) in the positive electrode active material layer (122). + It can supply ). Lithium ions (Li + As described with reference to FIGS. 4 and 5, ) can be delivered to the negative electrode (110) for the secondary battery to increase the capacity of the secondary battery (100). In particular, during the initial charging in the activation stage of the secondary battery (100), lithium ions (Li) are delivered to the negative electrode.+ By providing ) the irreversible capacity of the negative electrode, the capacity of the secondary battery (100) can be increased. That is, the performance and reliability of the secondary battery (100) can be improved.

[0098] According to embodiments of the technical concept of the present invention, a secondary battery (100) with improved performance and reliability can be provided.

[0099]

[0100] 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.

Claims

1. Positive current collector; A positive active material layer on the positive current collector above; and Includes a sacrificial cathode material, The above sacrificial cathode material comprises a buried portion within the cathode current collector and a contact portion in contact with the cathode active material layer, for a cathode for a secondary battery.

2. In Paragraph 1, The above positive current collector comprises a metal foil layer; and a carbon coating layer between the metal foil layer and the positive active material layer, A cathode for a secondary battery, wherein the buried portion of the sacrificial cathode material comprises a first portion surrounded by the carbon coating layer.

3. In Paragraph 2, The above-mentioned buried portion of the sacrificial cathode material further comprises a second portion within the metal foil layer, a cathode for a secondary battery.

4. In Paragraph 1, The contact portion of the sacrificial anode material is not embedded within the anode current collector, for a secondary battery anode.

5. In Paragraph 1, The above positive current collector and the above positive active material layer are stacked in a first direction, and The buried portion of the sacrificial anode material overlaps the anode current collector in a second direction intersecting the first direction, and The contact portion of the sacrificial cathode material does not overlap with the cathode current collector in the second direction, for a cathode for a secondary battery.

6. In Paragraph 1, The above sacrificial cathode material is a cathode for a secondary battery configured to provide lithium ions to the above cathode active material layer.

7. In Paragraph 1, The above positive active material layer comprises a positive active material, and A cathode for a secondary battery, wherein the content ratio of the sacrificial cathode material is 1 wt% to 5 wt% of the cathode active material.

8. A cathode comprising a cathode current collector and a layer of cathode active material on the cathode current collector; Anode comprising a positive current collector, a positive active material layer on the positive current collector, and a sacrificial positive material; and It includes a separator between the above-mentioned cathode and the above-mentioned anode, and The above sacrificial cathode material comprises a buried portion within the cathode current collector and a contact portion in contact with the cathode active material layer, forming an electrode assembly for a secondary battery.

9. In Paragraph 8, The above positive current collector comprises a metal foil layer; and a carbon coating layer between the metal foil layer and the positive active material layer, An electrode assembly for a secondary battery, comprising: a first portion surrounded by the carbon coating layer; and a second portion within the metal foil layer, wherein the buried portion of the sacrificial cathode material.

10. In Paragraph 8, The above cathode, the above separator, and the above anode are stacked in a first direction, and The buried portion of the sacrificial anode material overlaps the anode current collector in a second direction intersecting the first direction, and An electrode assembly for a secondary battery, wherein the contact portion of the sacrificial anode material does not overlap with the anode current collector in the second direction.

11. In Paragraph 8, The above sacrificial cathode is configured to provide lithium ions to the above negative electrode, an electrode assembly for a secondary battery.

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