Anode sheet and method of manufacturing the same, battery and vehicle

Abstract

A positive electrode sheet (100), a method for manufacturing the same, a battery, and a vehicle are disclosed. The positive electrode sheet (100) comprises a current collector (11), a first positive electrode active material layer (12), and a second positive electrode active material layer (13). The first positive electrode active material layer (12) is installed on at least one side of the current collector (11). The first positive electrode active material layer (12) comprises a first positive electrode active material. The first positive electrode active material comprises LiNixCoyMn1-x-yO2, and 0.6 ≤ x ≤ 0.95, 0.03 ≤ y ≤ 0.1, 0 <x+y<1이고; 제2 양극 활물질층(13)은 제1 양극 활물질층(12)의 집전체(11)와 반대되는 일측에 설치되고, 제2 양극 활물질층(13)은 제2 양극 활물질을 포함하고, 제2 양극 활물질의 전기화학적 전위 윈도우는 제1 양극 활물질의 전기화학적 전위 윈도우보다 크다.

Description

Technology Field

[0001] The present application is submitted based on a Chinese patent application with application number 202410157406.4 and a filing date of February 4, 2024, and claims priority to said Chinese patent application, the entire contents of said Chinese patent application are incorporated into the present application by reference.

[0002] This application relates to the field of battery technology, but is not limited thereto. Specifically, it relates to a positive electrode sheet and a method for manufacturing the same, as well as to a battery and a vehicle. Background Technology

[0003] As the new energy vehicle market continues to expand, the capacity of lithium-ion batteries is increasing year by year, and the demand for lithium-ion batteries is also rising, requiring features such as higher energy density, faster charging speeds, and longer cycle life.

[0004] Ternary cathode material (LiNi x CoyMn 1-x-y O2, 0 <x, y<1, NCM)는 비교적 높은 에너지 밀도를 가져, 신에너지 자동차 동력 배터리에 널리 사용되고 있다. 하지만 시장의 주류인 다른 양극재료 리튬인산철(LiFePO4)에 비해 NCM의 사이클 수명은 개선이 필요하다. NCM 리튬 이온 배터리의 양극 측 사이클 열화 원인에는 심각한 탈리튬 상태에서 NCM 재료 내부 구조의 변화, NCM 입자 표면에서의 부반응 발생 및 고전압에서 산소 발생에 따른 전해액 분해 등이 포함된다.

[0005] Current mainstream improvement measures all originate from the NCM material itself, enhancing structural and interfacial stability through means such as doping and coating; however, it is difficult to clearly identify the fundamental cause of the improvement, and problems such as increased material costs and reduced consistency exist.

[0006] At the sheet level, voltage varies depending on the internal location of the electrode, and this phenomenon is particularly evident when considering the problem of lithium deposition in the negative electrode sheet. In fact, during the charging and discharging process of a lithium-ion battery, there is also a problem where voltage varies depending on the location on the positive electrode sheet side; however, what is actually measured is only the voltage on the current collector side, not the voltage on the side closer to the separator of the positive electrode sheet. However, after the positive electrode sheet undergoes a long cycle, the voltage difference between the two ends of the positive electrode sheet can increase to 100mV to 150mV. As a result, the positive electrode material closer to the separator side receives a higher voltage, causing degradation behavior to occur preferentially in the positive electrode active material closer to the separator side, thereby affecting the cycle performance of the lithium-ion battery.

[0007] The following is an overview of the subject matter described in detail in this specification. This overview is not intended to limit the scope of protection of the claims.

[0008] One objective of the present application is to propose an anode sheet, the anode sheet of the present application having excellent voltage withstand performance and can improve the cycle performance of a battery.

[0009] Another objective of the present application is to propose a manufacturing method.

[0010] Another objective of the present application is to propose a battery.

[0011] Another objective of the present application is to propose a vehicle.

[0012] According to a first aspect of the present application, the present application proposes an anode sheet, and according to an embodiment of the present application, the anode sheet comprises a current collector, a first anode active material layer, and a second anode active material layer, wherein the first anode active material layer is installed on at least one side of the current collector, and the first anode active material layer comprises a first anode active material, and the first anode active material is LiNi x Co y Mn 1-x-yIncludes O2, 0.6≤x≤0.95, 0.03≤y≤0.1, 0 <x+y<1이고; 상기 제2 양극 활물질층은 상기 제1 양극 활물질층의 상기 집전체와 반대되는 일측에 설치되며, 상기 제2 양극 활물질층은 제2 양극 활물질을 포함하고, 상기 제2 양극 활물질의 전기화학적 전위 윈도우는 제1 양극 활물질의 전기화학적 전위 윈도우보다 크다.

[0013] According to the positive electrode sheet of the above embodiment of the present application, it comprises a current collector, a first positive electrode active material layer, and a second positive electrode active material layer, wherein the first positive electrode active material layer and the second positive electrode active material layer are sequentially formed on the current collector, that is, the first positive electrode active material layer is located between the current collector and the second positive electrode active material layer, and the electrochemical potential window of the second positive electrode active material within the second positive electrode active material layer is larger than the electrochemical potential window of the first positive electrode active material within the first positive electrode active material layer, thereby the voltage withstand performance of the second positive electrode active material layer is superior to that of the first positive electrode active material layer, so the voltage withstand performance of the positive electrode sheet can be improved and is advantageous for suppressing changes in the internal structure of the second positive electrode active material. Furthermore, the installation of the second positive electrode active material layer can also protect the first positive electrode active material and reduce damage to its structure caused by high voltage, thereby improving the cycle performance of the battery. In addition, the first positive electrode active material is LiNi x Co y Mn 1-x-y O2, 0.6≤x≤0.95, 0.03≤y≤0.1, 0 <x+y<1을 포함하고, 상기 재료는 다양한 활물질(예를 들어 Ni, Co, Mn)을 포함하여, 배터리 충방전 과정에서 양호한 화학적 안정성을 가지며, 배터리의 사이클 성능을 효과적으로 연장할 수 있는 바, 즉 상기 화학식을 만족하는 제1 양극 활물질을 제1 양극 활물질층에 적용함으로써, 배터리의 높은 사이클 성능을 유지할 수 있다. 이를 통해, 본 출원의 양극시트는 우수한 내고전압 성능을 가지고, 배터리의 사이클 성능을 향상시킬 수 있다.

[0014] According to a second aspect of the present application, the present application proposes a method for manufacturing the anode sheet, and according to an embodiment of the present application, the method comprises the steps of: forming a first anode active material layer comprising a first anode active material on at least one side of a current collector; and forming a second anode active material layer comprising a second anode active material on one side of the first anode active material layer far from the current collector to obtain an anode sheet.

[0015] According to the method for manufacturing the anode sheet of the above embodiment of the present application, the cycle performance of the battery can be improved by forming a first anode active material layer containing a first anode active material on at least one side of the current collector. By forming a second anode active material layer containing a second anode active material on the first anode active material layer, that is, the first anode active material layer is located between the current collector and the second anode active material layer, and the electrochemical potential window of the second anode active material is larger than the electrochemical potential window of the first anode active material, thereby making the voltage withstand performance of the second anode active material layer superior to that of the first anode active material layer, the voltage difference between the separator side and the current collector side of the anode sheet can be reduced during the charge-discharge cycle, and furthermore, changes in the internal structure of the anode active material can be suppressed, thereby improving the cycle performance of the battery.

[0016] According to a third aspect of the present application, the present application proposes a battery, and according to an embodiment of the present application, the battery comprises the positive electrode sheet or the positive electrode sheet manufactured by the above method.

[0017] According to the battery of the above embodiment of the present application, the overall performance of the battery is excellent, and at the same time, it can have excellent cycle performance.

[0018] According to a fourth aspect of the present application, the present application proposes a vehicle, and according to an embodiment of the present application, the vehicle includes the battery.

[0019] According to the vehicle of the above embodiment of the present application, the stability of the vehicle is excellent and market satisfaction is high.

[0020] Additional aspects and advantages of the present application are presented in part in the following description, and some will become clear from the description below or will be understood through the practice of the present application.

[0021] Other aspects will become clear after reading and understanding the drawings and detailed descriptions. Brief explanation of the drawing

[0022] FIG. 1 shows a schematic diagram of the structure of an anode sheet according to an embodiment of the present application date; FIG. 2 shows a schematic flowchart for manufacturing an anode sheet according to an embodiment of the present application date. Specific details for implementing the invention

[0023] The embodiments of the present application are described in detail below. Examples of the embodiments are illustrated in the drawings, and identical or similar reference numerals indicate identical or similar components or components having identical or similar functions. The embodiments described below are illustrative and are merely for the purpose of interpreting the present application and should not be understood as limiting the present application.

[0024] According to the first aspect of the present application, the present application proposes an anode sheet (100), and according to an embodiment of the present application, with reference to FIG. 1, the anode sheet (100) comprises a current collector (11), a first anode active material layer (12), and a second anode active material layer (13).

[0025] The current collector (11) can load and support the positive active material as a carrier of the positive active material and ensure stability during the battery charging and discharging process. As an example, the current collector (11) includes at least one of pure aluminum foil and composite aluminum foil, but is not limited thereto.

[0026] According to an embodiment of the present application, with reference to FIG. 1, the first positive active material layer (12) is installed on at least one side of the current collector (11), and the first positive active material layer (12) includes a first positive active material, and the first positive active material is LiNi x Co y Mn 1-x-y Includes O2, 0.6≤x≤0.95, 0.03≤y≤0.1, 0 <x+y<1이다. 예를 들어, x는 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95 등일 수 있고; y는 0.03, 0.05, 0.08, 0.1 등일 수 있다. 니켈 원소 함량을 상기 범위로 한정함으로써, 제1 양극 활물질의 방전 비용량을 높일 수 있으며, 나아가 리튬 배터리의 사이클 성능을 향상시킬 수 있고; 코발트 원소 함량을 상기 범위로 한정함으로써, 제1 양극 활물질 층상 구조의 형성에 유리하고, 제1 양극 활물질 내 Li / Ni 혼합 배열을 억제하여, 제1 양극 활물질 전기화학적 성능을 최적화하고; 망간 원소 함량을 상기 범위로 한정함으로써, 제1 양극 활물질 구조를 안정화하고, 제1 양극 활물질의 안정성을 향상시킬 수 있다. 이를 통해, 상기 화학식을 만족하는 제1 양극 활물질을 제1 양극 활물질층(12)에 적용함으로써, 배터리의 사이클 안정성을 더욱 향상시킬 수 있다.

[0027] According to some specific embodiments of the present application, the first positive active material comprises at least one of material A, material B, and material C, wherein material A is a single-crystal material and has the chemical formula LiNi x1 Co y1 Mn 1-x1-y1 O2, 0.6≤x1<0.8, 0.03≤y1≤0.1, 0 <x1+y1<1이다. 예를 들어 x1은 0.6, 0.65, 0.7, 0.75, 0.78 등일 수 있고, y1은 0.03, 0.05, 0.08, 0.1 등일 수 있고; 상기 재료 B는 단결정 재료이고, 화학식은 LiNi x2Co y2 Mn 1-x2-y2 O2, and 0.8≤x2≤0.95, 0.03≤y2≤0.1, 0 <x2+y2<1이다. 예를 들어 x2는 0.8, 0.84, 0.88, 0.9, 0.95 등일 수 있고; y2는 0.03, 0.05, 0.08, 0.1 등일 수 있고; 상기 재료 C는 다결정 재료이고, 화학식은 LiNi x3 Co y3 Mn 1-x3-y3 O2, and 0.8≤x3≤0.95, 0.03≤y3≤0.1, 0 <x3+y3<1이다. 예를 들어 x3은 0.8, 0.84, 0.88, 0.9, 0.95 등일 수 있고, y3은 0.03, 0.05, 0.08, 0.1 등일 수 있다. 재료 A, 재료 B 및 재료 C의 니켈 원소 함량에 따라, 재료 A는 단결정 중니켈 재료이며, 1차 입자로 구성된다. 재료 B는 단결정 고니켈 재료이며, 1차 입자로 구성된다. 재료 C는 다결정 고니켈 재료이며, 1차 입자가 응집되어 형성된 2차 입자로 구성된다. 한편, 상기 제1 양극 활물질은 다양한 활물질(예를 들어 Ni, Co, Mn)을 포함하여, 배터리가 동일한 부피에서 더 많은 전기 에너지를 저장할 수 있어, 양극시트(100)의 용량 발휘를 확보할 수 있고, 배터리의 에너지 밀도 향상에 유리하다. 다른 한편으로 안정적인 구조를 제공하여 부반응 발생을 줄이고, 사이클 과정에서 제1 양극 활물질의 가스 발생을 억제할 수 있으며, 배터리의 사이클 성능 향상에 유리하다.

[0028] As would be known to those skilled in the art, fine single crystal grains are generally referred to as primary particles, and particles formed by aggregation are referred to as secondary particles. The particle size of primary particles refers to the average particle size of primary particles and can be measured using a scanning electron microscope, while the average particle size of secondary particles is a term known in the art and can be measured using instruments and methods known in the art. For example, the average particle size of secondary particles can be measured using laser diffraction particle size analysis. Specifically, the average particle size of secondary particles can be measured using a laser particle size analyzer (e.g., Malvern Master Size 3000) by referring to the GB / T 19077-2016 standard.

[0029] It needs to be explained that medium nickel refers to the molar ratio A of nickel elements in the transition metal elements within the medium nickel material, where 60%≤A<80%, and high nickel refers to the molar ratio of nickel elements in the transition metal elements within the high nickel material being 80% or more.

[0030] According to some specific embodiments of the present application, the average particle size of the primary particles of material A is 2 μm to 6 μm. For example, the average particle size of the primary particles may be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, etc. By limiting the average particle size of the primary particles of material A to the above range, the contact area between the single-crystal medium nickel material and the electrolyte can be appropriately adjusted, and the lithium ion diffusion path can be shortened, thereby reducing capacity decay and thereby improving the cycle performance of the battery.

[0031] According to some specific embodiments of the present application, the volume average particle size Dv50 of the material A is 1 μm to 6 μm. For example, the volume average particle size Dv50 may be 1 μm, 2 μm, 3 μm, 5 μm, 6 μm, etc. By controlling the volume average particle size Dv50 of the material A to the above range, the pore structure and distribution of the first positive electrode active material can be controlled, the impregnation performance of the electrolyte and lithium ion transport efficiency can be improved, which is advantageous for improving the rate performance of the battery and furthermore, the cycle performance of the battery can be improved.

[0032] It needs to be explained that the volume average particle size Dv50 refers to the particle size at which the cumulative distribution of material A particles is 50%. In other words, the volume content of material A particles smaller than that particle size accounts for 50% of the total positive active material particles, and the volume content of material A particles larger than that particle size also accounts for 50% of the total positive active material particles. The size of the volume average particle size Dv50 is measured using a laser particle size analyzer.

[0033] According to some specific embodiments of the present application, the BET specific surface area of ​​material A is 0.5 m 2 / g to 1.5m 2 It is / g. For example, 0.5m 2 / g, 1m 2 / g, 1.5m 2 It may be / g, etc. By limiting the BET specific surface area of ​​material A to the above range, on the one hand, the electrochemical reaction activity of the first positive active material can be controlled, and it is advantageous to increase the energy density of the positive sheet (100). On the other hand, interfacial side reactions can be reduced and gas generation can be reduced, and furthermore, the cycle performance of the battery can be improved.

[0034] Specifically, the BET specific surface area of ​​material A can be measured by the following method. The BET specific surface area of ​​a solid material is measured using the gas adsorption BET method, utilizing nitrogen gas as the adsorbent. The BET specific surface area of ​​the sample is expressed as the number of nitrogen molecules densely coated (adsorbed) on the surface and the maximum cross-sectional area of ​​the molecules. By actually measuring the equilibrium saturated adsorption amount (V) of nitrogen molecules on the sample surface, calculating the monolayer saturated adsorption amount (Vm) using different theoretical models to obtain the number of molecules, and calculating the equivalent maximum cross-sectional area (Am) of nitrogen molecules using a surface close-packed hexagonal model, the BET specific surface area of ​​the sample to be measured can be determined. The calculation formula is S g =V m NA m / 22400W, and here S g is the BET specific surface area (m²) of the sample being measured 2 / g), V m ε is the saturated monolayer adsorption capacity (mL) of nitrogen molecules under standard conditions, A m The maximum equivalent cross-sectional area of ​​a nitrogen molecule (theoretical value A of close-packed hexagons) m =0.162 nm 2 ), W is the mass of the sample to be measured (g), and N is Avogadro's constant (6.02×10⁻⁶). 23 )am.

[0035] According to some specific embodiments of the present application, the average particle size of the primary particles of the material B is 1 μm to 3 μm. For example, it may be 1 μm, 2 μm, 3 μm, etc. By limiting the average particle size of the primary particles of the material B to the above range, the contact area between the material B and the electrolyte can be appropriately adjusted, and the lithium ion diffusion path can be shortened, thereby reducing capacity decay and thereby improving the cycle performance of the battery.

[0036] According to some specific embodiments of the present application, the volume average particle size Dv50 of the material B is 1 μm to 5 μm. For example, it may be 1 μm, 3 μm, 4 μm, 5 μm, etc. By controlling the Dv50 of the material B to the above range, the pore structure and distribution of the first positive electrode active material can be controlled, and the impregnation performance of the electrolyte and lithium ion transport efficiency can be improved, which is advantageous for improving the rate performance of the battery and furthermore, the cycle performance of the battery can be improved.

[0037] According to some specific embodiments of the present application, the BET specific surface area of ​​material B is 0.5 m 2 / g to 1.5m 2 It is / g. For example, 0.5m 2 / g, 1m 2 / g, 1.5m 2 It may be / g, etc. By limiting the BET specific surface area of ​​material B to the above range, on the one hand, the electrochemical reaction activity of the first positive active material can be controlled, and it is advantageous to increase the energy density of the positive sheet (100). On the other hand, interfacial side reactions can be reduced and gas generation can be reduced, and furthermore, the cycle performance of the battery can be improved.

[0038] According to some specific embodiments of the present application, the average particle size of the primary particles of the material C is 50 nm to 1000 nm. For example, it may be 50 nm, 100 nm, 300 nm, 600 nm, 800 nm, 1000 nm, etc. The material C is a polycrystalline material, that is, composed of secondary particles formed by the aggregation of primary particles, and by limiting the average particle size of the primary particles of the material C to the above range, structural parameters such as the pore size and BET specific surface area of ​​the material C can be controlled, and the ion diffusion path can be shortened and the ion conductivity increased, thereby improving the rate performance of the battery.

[0039] According to some specific embodiments of the present application, the average particle size of the secondary particles of the material C is 5 μm to 20 μm. For example, it may be 5 μm, 10 μm, 15 μm, 20 μm, etc. By limiting the average particle size of the secondary particles of the material C to the above range, the contact area between the material C and the electrolyte can be appropriately adjusted, and the lithium ion diffusion path can be shortened, thereby reducing capacity decay and thereby improving the cycle performance of the battery.

[0040] According to some specific embodiments of the present application, the volume average particle size Dv50 of the material C is 7 μm to 18 μm. For example, it may be 7 μm, 10 μm, 15 μm, 18 μm, etc. By limiting the volume average particle size Dv50 of the material C to the above range, the pore structure and distribution of the first positive electrode active material can be controlled, and the impregnation performance of the electrolyte and lithium ion transport efficiency can be improved, which is advantageous for improving the rate performance of the battery and furthermore, the cycle performance of the battery can be improved.

[0041] According to some specific embodiments of the present application, the BET specific surface area of ​​material C is 0.2 m 2 / g to 1m 2 It is / g. For example, 0.2m 2 / g, 0.5m 2 / g, 0.8m 2 / g, 1m 2 It may be / g, etc. By limiting the BET specific surface area of ​​material C to the above range, on the one hand, the electrochemical reaction activity of the first positive active material can be controlled, and it is advantageous to increase the energy density of the positive sheet (100). On the other hand, interfacial side reactions can be reduced and gas generation can be reduced, and furthermore, the cycle performance of the battery can be improved.

[0042] According to some specific embodiments of the present application, the first positive electrode active material comprises material B and material C. Material B is a single-crystal high-nickel material, and material C is a polycrystalline high-nickel material. By mixing the single-crystal high-nickel material and the polycrystalline high-nickel material and using them as the first positive electrode active material, on the one hand, the polycrystalline material has excellent processing fluidity and the single-crystal material has excellent mechanical strength, and by using a mixture of these two materials, even better processing performance can be obtained. On the other hand, the polycrystalline material has high energy density and good cycle stability, and the single-crystal material has excellent cycle performance and high-speed charge / discharge capability. By using a mixture of these two materials, the advantages of these materials can be comprehensively utilized to improve the cycle performance of the battery.

[0043] According to some specific embodiments of the present application, the mass ratio of material B and material C is (2 - 3):(7 - 8). For example, it may be 2:8, 3:7, etc. By limiting the mass ratio of material B and material C to the above range, the ratio of material B and material C within the first positive active material layer (12) can be controlled, which is advantageous for improving the cycle performance of the battery.

[0044] According to some specific embodiments of the present application, when the first positive active material comprises material B and material C, the volume average particle size Dv50 of the first positive active material is 5 μm to 15 μm. For example, it may be 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, etc. By limiting the volume average particle size Dv50 of the mixture of material B and material C to the above range, the contact area between the first positive active material and the electrolyte can be appropriately adjusted, and the lithium ion diffusion path can be shortened, thereby reducing capacity decay and thereby improving the cycle performance of the battery.

[0045] According to an embodiment of the present application, with reference to FIG. 1, a second positive active material layer (13) is installed on one side opposite to the current collector (11) of the first positive active material layer (12), and the second positive active material layer (13) includes a second positive active material, and the electrochemical potential window of the second positive active material is larger than the electrochemical potential window of the first positive active material. By forming a second positive active material layer (13) containing a second positive active material on the first positive active material layer (12), that is, the first positive active material layer (12) is located between the current collector (11) and the second positive active material layer (13), and the electrochemical potential window of the second positive active material is larger than the electrochemical potential window of the first positive active material, thereby making the voltage withstand performance of the second positive active material layer (13) superior to that of the first positive active material layer (12), and during the charge / discharge cycle process, the second positive active material layer (13) can withstand the high voltage on the separator side, and furthermore, the voltage difference between the separator side and the current collector (11) side of the positive sheet (100) can be reduced, and it is advantageous to suppress changes in the internal structure of the second positive active material, and the installation of the second positive active material layer protects the first positive active material and reduces damage to its structure caused by high voltage, thereby improving the cycle performance of the battery.

[0046] An electrochemical potential window refers to the range between a single positive potential and a single negative potential that an electrode material exists stably without decomposing.

[0047] According to some specific embodiments of the present application, the second positive active material comprises at least one of a lithium-rich manganese-based material and a lithium manganese iron phosphate, wherein the chemical formula of the lithium-rich manganese-based material is aLi2MnO3·(1-a)LiNi x4 Co y4 Mn 1-x4-y4O2, and 0≤a≤1, 0.2≤x4≤1, 0≤y4≤0.5, 0 <x4+y4<1이고, 예를 들어 a는 0.2, 0.5, 0.8 등일 수 있고, x4는 0.33, 0.5, 0.6, 0.7, 0.8 등일 수 있고, y4는 0, 0.1, 0.2, 0.3, 0.33, 0.4 등일 수 있고; 상기 리튬 망간 철 인산염의 화학식은 LiMn x5 Fe 1-x5 PO4, 0.2≤x5≤0.8, and for example, x5 can be 0.2, 0.4, 0.5, 0.6, 0.8, etc. The second positive active material has a high electrochemical potential window, so it can effectively withstand a situation where the voltage on the separator side is high during charging and discharging of the positive sheet, and improves the structural stability of the side of the positive sheet close to the separator and the structural stability inside the positive active material, which is advantageous for improving the cycle performance of the battery.

[0048] According to some specific embodiments of the present application, the first positive active material comprises material A, and the second positive active material comprises a lithium-rich manganese-based material. When a medium nickel material A is selected as the first positive active material, a lithium-rich manganese-based material can be selected as the second positive active material. In this case, the medium nickel material may include various active materials (e.g., Ni, Co, Mn), allowing the battery to store more electrical energy in the same volume, thereby ensuring the capacity of the positive sheet (100) and being advantageous for improving the energy density of the battery. Additionally, Ni, Co, and Mn possess excellent chemical stability during the battery charging and discharging process, which can effectively extend the cycle performance of the battery. The lithium-rich manganese-based material has a high electrochemical potential window (4.6V), which can effectively withstand high voltage on the separator side during positive sheet charging and discharging. It also improves structural stability on the side of the positive sheet close to the separator and structural stability within the positive active material, which is advantageous for improving the cycle performance of the battery.

[0049] According to some specific embodiments of the present application, the first positive active material comprises at least one of material B and material C, and the second positive active material comprises lithium manganese iron phosphate. When a high-nickel material is selected as the first positive active material, lithium manganese iron phosphate can be selected as the second positive active material. Here, the high-nickel material includes various active materials (e.g., Ni, Co, Mn), so that the battery can store more electrical energy in the same volume, thereby ensuring the capacity of the positive sheet (100). Furthermore, Ni, Co, and Mn have excellent chemical stability during the battery charging and discharging process, which can effectively extend the cycle performance of the battery. Lithium manganese iron phosphate has a high electrochemical potential window (greater than 4.2V), which can effectively withstand situations where the voltage on the separator side is high during the charging and discharging of the positive sheet. It improves the structural stability of the side of the positive sheet near the separator and the structural stability within the positive active material, which is advantageous for improving the cycle performance of the battery.

[0050] According to some specific embodiments of the present application, the average particle size of the primary particles of the lithium-rich manganese-based material is 50 nm to 800 nm. For example, it may be 50 nm, 100 nm, 300 nm, 500 nm, 800 nm, etc. The lithium-rich manganese-based material is a polycrystalline material composed of secondary particles formed by the aggregation of primary particles. By limiting the average particle size of the primary particles of the lithium-rich manganese-based material to the above range, on the one hand, structural parameters such as the pore size and BET specific surface area of ​​the polycrystalline material can be controlled, and the lithium ion diffusion path can be shortened and ion conductivity increased, thereby improving the charge / discharge performance of the battery. On the other hand, the mechanical strength and thermal stability of the second cathode active material can be improved, thereby improving the cycle performance of the battery.

[0051] According to some specific embodiments of the present application, the average particle size of the secondary particles of the lithium-rich manganese-based material is 10 μm to 20 μm. For example, it may be 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, etc. By limiting the average particle size of the secondary particles of the lithium-rich manganese-based material to the above range, the contact area between the lithium-rich manganese-based material and the electrolyte can be appropriately adjusted, and the lithium ion diffusion path can be shortened, thereby reducing capacity decay and thereby improving the cycle performance of the battery.

[0052] According to some specific embodiments of the present application, the volume average particle size Dv50 of the lithium-rich manganese-based material is 10 μm to 20 μm. For example, it may be 10 μm, 12 μm, 15 μm, 17 μm, 20 μm, etc. By limiting the volume average particle size Dv50 of the lithium-rich manganese-based material to the above range, the pore structure and distribution of the second cathode active material can be controlled, the impregnation performance of the electrolyte and lithium ion transport efficiency can be improved, which is advantageous for improving the rate performance of the battery and furthermore, the cycle performance of the battery can be improved.

[0053] According to some specific embodiments of the present application, the BET specific surface area of ​​the lithium-rich manganese-based material is 0.2 m 2 / g to 1m 2 It is / g. For example, 0.2m 2 / g, 0.5m 2 / g, 0.7m 2 / g, 0.9m 2 / g, 1m 2 It may be / g, etc. By limiting the BET specific surface area of ​​the lithium-rich manganese-based material to the above range, on the one hand, the electrochemical reaction activity of the second cathode active material can be controlled, and it is advantageous to increase the energy density of the cathode sheet (100). On the other hand, interfacial side reactions can be reduced and gas generation can be reduced, and furthermore, the cycle performance of the battery can be improved.

[0054] According to some specific embodiments of the present application, the average particle size of the primary particles of the lithium manganese iron phosphate is 20 nm to 300 nm. For example, it may be 20 nm, 50 nm, 100 nm, 200 nm, 300 nm, etc. On the one hand, structural parameters such as the pore size and BET specific surface area of ​​the lithium manganese iron phosphate can be controlled, and the lithium ion diffusion path can be shortened and the ion conductivity increased, thereby improving the charge / discharge performance of the battery. On the other hand, the mechanical strength and thermal stability of the second cathode active material can be increased, thereby improving the cycle performance of the battery.

[0055] According to some specific embodiments of the present application, the volume average particle size Dv50 of the lithium manganese iron phosphate is 0.2 μm to 1.5 μm. For example, it may be 0.2 μm, 0.5 μm, 1 μm, 1.5 μm, etc. By controlling the Dv50 of the lithium manganese iron phosphate to the above range, the pore structure and distribution of the second cathode active material can be controlled, and the impregnation performance of the electrolyte and lithium ion transport efficiency can be improved, which is advantageous for improving the rate performance of the battery and furthermore, the cycle performance of the battery can be improved.

[0056] According to some specific embodiments of the present application, the BET specific surface area of ​​the lithium manganese iron phosphate is 10 m² 2 / g to 30m 2 It is / g. For example, 10m 2 / g, 20m 2 / g, 30m 2 It may be / g, etc. By limiting the BET specific surface area of ​​lithium manganese iron phosphate to the above range, on the one hand, the electrochemical reaction activity of the second positive active material can be controlled, and it is advantageous to increase the energy density of the positive sheet (100). On the other hand, interfacial side reactions can be reduced and gas generation can be reduced, and furthermore, the cycle performance of the battery can be improved.

[0057] According to some specific embodiments of the present application, the lithium manganese iron phosphate further comprises a carbon coating layer, wherein the carbon coating layer covers at least a portion of the surface of the lithium manganese iron phosphate. By forming a carbon coating layer on at least a portion of the surface of the lithium manganese iron phosphate, on the one hand, the lithium manganese iron phosphate is prevented from coming into direct contact with the electrolyte, thereby reducing the occurrence of side reactions and the amount of gas generated, and further improving the cycle stability of the battery. On the other hand, the conductivity of the material is improved, thereby further improving the rate performance of the battery.

[0058] According to some specific embodiments of the present application, the mass ratio of the carbon coating layer is 0.2% to 3% based on the total mass of the lithium manganese iron phosphate. For example, it may be 0.2%, 0.5%, 1%, 2%, 3%, etc. By limiting the mass ratio of the carbon coating layer to the above range, direct contact between the lithium manganese iron phosphate and the electrolyte is prevented, thereby reducing the occurrence of side reactions and the amount of gas generated, and further improving the cycle stability of the battery.

[0059] According to some specific embodiments of the present application, the mass ratio of the first positive active material layer (12) is 70% to 90% based on the total mass of the first positive active material layer (12) and the second positive active material layer (13). For example, it may be 70%, 80%, 90%, etc. By limiting the mass ratio of the first positive active material layer (12) to the above range, the first positive active material layer (12) can be secured to satisfy high energy density and stability requirements, and at the same time, the second positive active material layer (13) can have high voltage resistance performance, allowing it to withstand a situation where the separator side voltage is high during charging and discharging of the positive sheet (100), which is advantageous for improving the cycle performance of the battery.

[0060] According to some specific embodiments of the present application, the compression density of the positive active material layer in the positive sheet (100) is 3.2 g / cm³ to 3.7 g / cm³, and may be, for example, 3.2 g / cm³, 3.5 g / cm³, 3.7 g / cm³, etc. By limiting the compression density of the positive active material layer of the positive sheet (100) to the above range, the insertion and extraction of lithium ions can be facilitated more smoothly, which is advantageous for increasing the discharge capacity of the battery, reducing internal resistance and polarization losses, and improving the cycle performance of the battery.

[0061] It needs to be explained that the positive active material layer is a collective term for the first positive active material layer (12) and the second positive active material layer (13).

[0062] According to some specific embodiments of the present application, the areal density of the positive active material layer in the positive sheet (100) is 100 g / m² 2 Up to 400g / m² 2 It can be, for example, 100g / m² 2 , 250g / m 2 , 400g / m 2 It can be done by controlling the areal density of the positive electrode active material layer. This optimizes the lithium ion transport path and reduces internal resistance, which is advantageous for improving the battery's cycle performance.

[0063] It should be explained that a first positive active material layer (12) may be formed on one side of the current collector (11), or a first positive active material layer (12) may be formed on both sides of the current collector (11), and a person skilled in the art may choose according to actual needs.

[0064] According to a second aspect of the present application, the present application proposes a method for manufacturing the anode sheet (100). According to an embodiment of the present application, with reference to FIG. 2, the method comprises the following steps.

[0065] S1. A first positive active material layer (12) containing a first positive active material is formed on at least one side of the current collector (11).

[0066] In the above step, a first positive active material layer (12) is formed on at least one side of the current collector (11) using a first positive active material. By forming a first positive active material layer (12) containing the first positive active material on at least one side of the current collector (11), the cycle performance of the battery can be improved.

[0067] According to one specific embodiment of the present application, the step of forming a first positive active material layer (12) comprising a first positive active material on at least one side of a current collector (11) is performed according to the following step.

[0068] S11. A first slurry is prepared by mixing a first positive active material, a first conductive agent, and a first solvent.

[0069] In the above step, a first positive active material, a first conductive agent, and a first solvent can be mixed and stirred to obtain a first slurry.

[0070] According to some specific embodiments of the present application, the first slurry further comprises a first binder, and the mass ratio of the first positive active material, the first binder, and the first conductive agent is (0.95 - 0.98):(0 - 0.3):(0.02 - 0.05). For example, it may be 0.95:0.1:0.02, 0.98:0.3:0.05, 0.96:0.2:0.04, etc. The first positive active material can improve the cycle performance of the battery, and the first binder and the first conductive agent perform the role of connecting the first positive active material in the positive sheet (100) and reinforcing the electrode structure, and by limiting the mass ratio of the first positive active material, the first binder, and the first conductive agent to the above range, a high energy density of the battery can be secured, and at the same time, the cycle performance of the battery can be improved.

[0071] As an example, the first binder comprises, but is not limited to, polyvinylidene fluoride. The first conductive agent comprises, but is not limited to, at least one of conductive carbon black, carbon nanotubes, and carbon nanofibers. The first solvent comprises, but is not limited to, N-methylpyrrolidone.

[0072] S12. The first slurry is applied to at least one side of the current collector (11) and dried to obtain the first positive active material layer (12).

[0073] In this step, the first slurry is applied to at least one side of the current collector (11) and a first drying is performed to obtain the first positive active material layer (12).

[0074] According to some specific embodiments of the present application, the temperature of the first drying is 60°C to 80°C. For example, it may be 60°C, 70°C, 80°C, etc. By limiting the temperature of the first drying to the above range, on the one hand, the rate of moisture evaporation can be controlled to prevent cracks from forming on the surface of the material. On the other hand, the curing process of the binder is accelerated so that the anode sheet (100) has good mechanical strength and stability.

[0075] According to some specific embodiments of the present application, the time for the first drying is 3 min to 10 min. For example, it may be 3 min, 5 min, 7 min, etc. By limiting the time for the first drying to the above range, the curing of the anode sheet (100) structure can be promoted, and the stability and consistency of the anode sheet (100) can be improved.

[0076] S2. A second positive active material layer (13) containing a second positive active material is formed on one side of the first positive active material layer (12) that is far from the current collector (11).

[0077] In this step, a second positive active material layer (13) containing a second positive active material is formed on the first positive active material layer (12), that is, the first positive active material layer (12) is located between the current collector (11) and the second positive active material layer (13), and the electrochemical potential window of the second positive active material is larger than the electrochemical potential window of the first positive active material, thereby making the voltage withstand performance of the second positive active material layer (13) superior to that of the first positive active material layer (12), and during the charge / discharge cycle process, the voltage difference between the separator side of the positive sheet (100) and the current collector (11) side can be reduced, and furthermore, changes in the internal structure of the positive active material can be suppressed, thereby improving the cycle performance of the battery.

[0078] According to one specific embodiment of the present application, the step of forming a second positive active material layer (13) containing a second positive active material on one side of the first positive active material layer (12) far from the current collector (11) is performed according to the following step.

[0079] S21. A second positive active material, a second conductive agent, and a second solvent are mixed to obtain a second slurry.

[0080] In this step, a second slurry can be obtained by mixing and stirring the second positive active material, the second conductive agent, and the second solvent.

[0081] According to some specific embodiments of the present application, the second slurry further comprises a second binder, and the mass ratio of the second positive active material, the second binder, and the second conductive agent is (0.95 - 0.98):(0 - 0.3):(0.02 - 0.05). For example, it may be 0.95:0.1:0.02, 0.98:0.3:0.05, 0.96:0.2:0.04, etc. The second positive active material can improve the voltage resistance and cycle performance of the positive sheet (100), and the second binder and second conductive agent perform the role of connecting the second positive active material in the positive sheet (100) and reinforcing the structure of the positive sheet (100). By limiting the mass ratio of the second positive active material, the second binder, and the second conductive agent to the above range, it can withstand a situation where the separator side voltage is high during charging and discharging of the positive sheet (100), and is advantageous for improving the cycle performance of the battery.

[0082] As an example, the second binder comprises, but is not limited to, polyvinylidene fluoride. The second conductive agent comprises, but is not limited to, at least one of conductive carbon black, carbon nanotubes, and carbon nanofibers. The second solvent comprises, but is not limited to, N-methylpyrrolidone.

[0083] S22. The second slurry is applied to one side of the first positive active material layer (12) far from the current collector (11) and dried a second time to obtain the second positive active material layer (13).

[0084] In this step, the second slurry is applied to one side of the first positive active material layer (12) far from the current collector (11), and a second drying is performed. After drying, the second positive active material layer (13) is rolled to obtain, that is, a positive sheet (100).

[0085] According to some specific embodiments of the present application, the temperature of the secondary drying is 110°C to 130°C. For example, it may be 110°C, 120°C, 130°C, etc. By limiting the temperature of the secondary drying to the above range, on the one hand, the rate of moisture evaporation can be controlled to prevent cracks from forming on the surface of the material. On the other hand, the curing process of the binder is accelerated so that the anode sheet (100) has good mechanical strength and stability.

[0086] According to some specific embodiments of the present application, the time for the secondary drying is 5 min to 20 min. For example, it may be 5 min, 10 min, 20 min, etc. By limiting the time for the secondary drying to the above range, the curing of the structure of the anode sheet (100) can be promoted, and the stability and consistency of the anode sheet (100) can be improved.

[0087] According to a third aspect of the present application, the present application proposes a battery. According to an embodiment of the present application, the battery comprises the anode sheet (100) described above or an anode sheet (100) manufactured by the method described above, and the anode sheet (100) has excellent cycle performance, so that the overall performance of the battery is excellent and can simultaneously have excellent cycle performance.

[0088] A battery refers to a battery that can be used continuously by activating the active material through a charging method after discharge.

[0089] Generally, a battery includes a positive electrode sheet (100), a negative electrode sheet, a separator, and an electrolyte. During the battery charging and discharging process, active ions (lithium ions) reciprocate between the positive electrode sheet (100) and the negative electrode sheet, being inserted and removed. The separator is installed between the positive electrode sheet (100) and the negative electrode sheet and serves to separate them. The electrolyte serves to conduct ions between the positive electrode sheet (100) and the negative electrode sheet.

[0090] According to some specific embodiments of the present application, the battery may be a lithium-ion secondary battery.

[0091] In the embodiments of the present application, the shape of the battery is not specifically limited and may be cylindrical, prismatic, or any other shape.

[0092] According to a fourth aspect of the present application, the present application proposes a vehicle. According to an embodiment of the present application, the vehicle comprises the battery described above, and the battery has excellent cycle performance, thereby, compared to the prior art, the vehicle has superior stability and high market satisfaction. For example, the vehicle may include, but is not limited to, a pure electric vehicle, a hybrid electric vehicle, etc.

[0093] The methods of the present disclosure are described below by combining examples. Those skilled in the art will understand that the following examples are for illustrative purposes only and should not be construed as limiting the scope of the present disclosure. Where specific technical or conditional details are not specified in the examples, the process shall be carried out in accordance with technical or conditional details or product descriptions found in literature of the art. Unless otherwise specified, the reagents and equipment used are all commercially available products.

[0094] Example 1

[0095] 1. Preparation of the first positive electrode active material layer

[0096] (1) Selection of raw materials: The first positive active material is material A (single-crystal medium nickel material), and its chemical formula is LiNi 0.68 Co 0.07 Mn 0.25 It is O2, the average particle size of the primary particles of Material A is 5 μm, the volume average particle size Dv50 of Material A is 3.52 μm, and the BET specific surface area of ​​Material A is 0.85 m² 2 / g; the first binder is polyvinylidene fluoride; the first conductive agent is conductive carbon black and carbon nanotubes, and the first solvent is N-methylpyrrolidone.

[0097] (2) Preparation of the first slurry: Material A, conductive carbon black, carbon nanotubes and polyvinylidene fluoride are mixed in a mass ratio of 97.3:1.2:0.5:1, then mixed with an appropriate amount of N-methylpyrrolidone and stirred uniformly to obtain the first slurry.

[0098] (3) The first slurry is uniformly applied to a composite aluminum current collector, and the composite aluminum current collector is composed of two layers of aluminum foil with a thickness of 1.5 μm and a polypropylene intermediate layer with a thickness of 10 μm, and then dried at a temperature of 60°C for 10 min to obtain a first positive active material layer.

[0099] 2. Preparation of the second positive electrode active material layer

[0100] (1) Selection of raw materials: The second cathode active material is a lithium-rich manganese-based material, and its chemical formula is 0.5Li2MnO3·0.5LiNi 0.33 Co 0.34 Mn 0.33 It is O2, the average particle size of the primary particles of the lithium-rich manganese-based material is 400 nm, the average particle size of the lithium-rich manganese-based material is 14 μm, the volume average particle size Dv50 of the lithium-rich manganese-based material is 13.38 μm, and the BET specific surface area of ​​the lithium-rich manganese-based material is 0.44 m² 2 / g; the second binder is polyvinylidene fluoride; the second conductive agent is conductive carbon black and carbon nanotubes, and the second solvent is N-methylpyrrolidone.

[0101] (2) Preparation of the second slurry: A lithium-rich manganese-based material, conductive carbon black, carbon nanotubes, and polyvinylidene fluoride are mixed in a mass ratio of 97.3:1.2:0.5:1, then mixed with an appropriate amount of N-methylpyrrolidone and stirred uniformly to obtain the second slurry.

[0102] (3) The second slurry is uniformly applied onto the dried first positive active material layer, dried at a temperature of 110°C for 15 minutes, and then rolled to obtain the second positive active material layer, i.e., the positive sheet. Here, the mass ratio of the first positive active material layer to the second positive active material layer is 7:3.

[0103] 3. Manufacturing of the battery: The above-manufactured positive electrode sheet is assembled with a graphite negative electrode sheet, a separator, and an electrolyte to form a pouch-type battery, and then a subsequent performance test is performed, wherein the separator is a PP / PE composite thin film material, the electrolyte is a mixed solvent with a mass ratio of EC:DEC:DMC = 1:1:1, and the electrolyte is 1M lithium hexafluorophosphate.

[0104] The batteries of Examples 2 to 8 and Comparative Examples 1 to 4 are identical to Example 1 except that the parameters of the positive electrode sheet are different (see Table 1).

[0105] The experimental parameters of the anode sheets of Examples 1 to 8 and Comparative Examples 1 to 4 of the present application are shown in Table 1.

[0106] First positive active material layer Second positive active material layer First positive active material Chemical formula of the first positive electrode active material Dv50 / μm of the first positive electrode active material BET specific surface area of ​​the first positive active material / m² 2 ·g -1 Chemical formula of the second positive electrode active material Dv50 / μm of the second positive electrode active material BET specific surface area / m² of the second positive active material 2 ·g -1 Example 1 Material A LiNi 0.68 Co 0.07 Mr 0.25 O2 3.52 0.85 0.5Li2MnO3·0.5LiNi 0.33 Co 0.34 Mn 0.33 O2 13.38 0.44 Example 2 Material A LiNi 0.75 Co 0.1 Mr 0.15 O2 3.43 0.80 0.5Li2MnO3·0.5LiNi 0.33 Co 0.34 Mn 0.33 O2 13.38 0.44 Example 3 Material A LiNi 0.68 Co 0.07 Mr 0.25 O2 3.52 0.85 0.5Li2MnO3·0.5LiNi 0.5 Co 0.1 Mn 0.4 O2 12.43 0.45 Example 4 Material A LiNi 0.75 Co 0.1 Mr 0.15 O2 3.43 0.80 0.5Li2MnO3·0.5LiNi 0.5 Co 0.1 Mn 0.4 O2 12.43 0.45 Example 5 Material B, Material C LiNi 0.9 Co 0.07 Mr 0.03 O2 10.72 0.43 LiMn 0.6 Feb 0.4 PO4 0.602 18.756 Example 6 Material B, Material C LiNi 0.8 Co 0.1 Mr 0.1 O2 11.553 0.37 LiMn 0.6 Feb 0.4 PO4 0.602 18.756 Example 7 Material B, Material C LiNi 0.9 Co 0.07 Mr 0.03 O2 10.72 0.43 LiMn 0.4 Feb 0.6 PO4 0.549 16.066 Example 8 Material B, Material C LiNi 0.8 Co 0.1 Mr 0.1 O2 11.553 0.37 LiMn 0.4 Feb 0.6 PO4 0.549 16.066 Comparative Example 1 Material A LiNi 0.68 Co 0.07 Mr 0.25 O2 3.52 0.85 / Comparative Example 2 Material A LiNi 0.75 Co 0.1 Mr 0.15 O2 3.43 0.80 / Comparative Example 3 Material B, Material C LiNi 0.9 Co 0.07 Mr 0.03 O2 10.72 0.43 / Comparative Example 4 Material B, Material C LiNi 0.8 Co 0.1 Mr 0.1 O2 11.553 0.37 /

[0107] " / " means none. Test and Analysis

[0108] Cycle performance was tested for the pouch-type batteries prepared in Examples 1 to 8 and Comparative Examples 1 to 4 under the same conditions. The specific test method is as follows.

[0109] When the first positive active material in the first positive active material layer is material A, the electrochemical test voltage is 2.8V to 4.4V; when the first positive active material in the first positive active material layer is a mixture of material B and material C, the electrochemical test voltage is 2.8V to 4.25V.

[0110] Cycle performance test: In the charge / discharge cycle, the charge / discharge rate is set to 0.33C and the test temperature to 25℃, and the capacity retention rate after 1000 cycles is calculated, and the capacity retention rate after 1000 cycles (%) = capacity after 1000 cycles / initial capacity.

[0111] The test results are shown in Table 2.

[0112] Initial capacity (Ah) Dose retention rate (%) after 1,000 cycles Example 1 3.612 88.9 Example 2 3.729 88.2 Example 3 3.621 87.3 Example 4 3.735 87.1 Example 5 3.764 85.1 Example 6 3.659 86.2 Example 7 3.789 85.4 Example 8 3.672 86.8 Comparative Example 1 3.628 82.4 Comparative Example 2 3.737 81.7 Comparative Example 3 3.844 80.3 Comparative Example 4 3.782 80.9

[0113] Referring to Tables 1 and 2 together, the batteries obtained in Examples 1 to 8 have superior cycle performance compared to the batteries obtained in Comparative Examples 1 to 4, wherein Example 1 comprises a first positive active material layer comprising material A and a second positive active material layer comprising a lithium-rich manganese-based material, the mass fraction ratio of the first positive active material layer to the second positive active material layer is 7:3, the charge / discharge voltage window is 2.8V to 4.4V, and since the voltage at the end of charging is relatively high, a lithium-rich manganese-based material, which is a high voltage withstand material, was used as the second positive active material layer; Comparative Example 1 is a pouch-type battery manufactured using an anode sheet made solely of material A, and since there is no surface voltage withstand layer, in the later stages of the charge-discharge cycle, the voltage at a point near the separator of the anode sheet is higher than at a point near the current collector; consequently, structural changes in the anode material at the point near the separator of the anode sheet occur preferentially, and side reactions occur more easily, thereby affecting the cycle performance of the battery. Example 1 has a surface voltage withstand layer, so the discharge capacity of the pouch-type battery is slightly reduced compared to Comparative Example 1, which is because the lithium-rich manganese-based material does not fully exhibit its own capacity in the charge-discharge voltage range (2.8V to 4.4V) of material A; The capacity retention rate after 1,000 cycles of Example 1 is much higher than that of Comparative Example 1, because the lithium-rich manganese-based material of the second positive active material layer can withstand a higher voltage and exhibit a higher capacity in the later stages of the cycle. Through the capacity replenishment method, the capacity decay of the pouch-type battery is suppressed and excellent cycle performance is exhibited. At the same time, the lithium-rich manganese-based material is a polycrystalline large particle, which can form relatively large pores in the second positive active material layer. Since the curvature of the pores is relatively low, it can provide a high-speed transport pathway for lithium ions, which is advantageous for improving the rate performance of the battery.

[0114] In this way, the present application separates the positive active material coating layer of the positive sheet into a first positive active material layer and a second positive active material layer, prepares slurries with different mass fractions for each, and then applies, dries, and rolls them layer by layer on a current collector to produce a positive sheet having excellent cycle performance, thereby achieving the voltage resistance of the positive active material layer and simultaneously optimizing the internal pore structure of the positive sheet to further improve the cycle performance of the battery.

[0115] In the description of this specification, expressions such as the reference terms “one embodiment,” “some embodiment,” “example,” “specific example,” “some embodiment,” or “some example” mean that specific features, structures, materials, or properties described in combination with said embodiment or example are included in at least one embodiment or example of this application. In this specification, exemplary expressions of said terms are not necessarily intended for the same embodiment or example. Furthermore, the described specific features, structures, materials, or properties may be combined in an appropriate manner in any one or more embodiments or examples. Meanwhile, unless there is a mutual contradiction, a person skilled in the art may combine and combine different embodiments or examples and features of each embodiment or example described in this specification.

[0116] Although embodiments of the present application have been illustrated and described above, as can be understood, the above-described embodiments are merely illustrative and should not be understood as limiting the present application, and a person skilled in the art may make changes, modifications, substitutions, and variations to the above-described embodiments within the scope of the present application.

Claims

Claim 1 Current collector; a first positive active material layer installed on at least one side of the current collector - the first positive active material layer comprises a first positive active material, and the first positive active material is LiNi x Co y Mn 1-x-y Includes O2, 0.6≤x≤0.95, 0.03≤y≤0.1, 0 <x+y<1임 - ;상기 제1 양극 활물질층의 상기 집전체와 반대되는 일측에 설치되는 제2 양극 활물질층 - 상기 제2 양극 활물질층은 제2 양극 활물질을 포함하고, 상기 제2 양극 활물질의 전기화학적 전위 윈도우는 제1 양극 활물질의 전기화학적 전위 윈도우보다 큼 - 을 포함하는 양극시트. Claim 2 In claim 1, the first positive active material comprises at least one of material A, material B, and material C, wherein material A is a single-crystal material and has the chemical formula LiNi x1 Co y1 Mn 1-x1-y1 O2, 0.6≤x1<0.8, 0.03≤y1≤0.1, 0 <x1+y1<1이고;상기 재료 B는 단결정 재료이고, 화학식은 LiNi x2 Co y2 Mn 1-x2-y2 O2, and 0.8≤x2≤0.95, 0.03≤y2≤0.1, 0 <x2+y2<1이고;상기 재료 C는 다결정 재료이고, 화학식은 LiNi x3 Co y3 Mn 1-x3-y3 O2, and 0.8≤x3≤0.95, 0.03≤y3≤0.1, 0 <x3+y3<1인 양극시트. Claim 3 In paragraph 2, the volume average particle size Dv50 of the material A is 1 μm to 6 μm; and / or, the BET specific surface area of ​​the material A is 0.5 m 2 / g to 1.5m 2 Anode sheet with a g content. Claim 4 In paragraph 2, the volume average particle size Dv50 of the material B is 1 μm to 5 μm; and / or, the BET specific surface area of ​​the material B is 0.5 m 2 / g to 1.5m 2 Anode sheet with a g content. Claim 5 In paragraph 2, the volume average particle size Dv50 of the material C is 7 μm to 18 μm; and / or, the BET specific surface area of ​​the material C is 0.2 m 2 / g to 1m 2 Anode sheet with a g content. Claim 6 In claim 1, the second positive active material comprises at least one of a lithium-rich manganese-based material and a lithium manganese iron phosphate, wherein the chemical formula of the lithium-rich manganese-based material is aLi2MnO3·(1-a)LiNi x4 Co y4 Mn 1-x4-y4 O2, and 0≤a≤1, 0.2≤x4≤1, 0≤y4≤0.5, 0 <x4+y4<1이고;상기 리튬 망간 철 인산염의 화학식은 LiMn x5 Fe 1-x5 A positive sheet that is PO4 and has 0.2≤x5≤0.

8. Claim 7 In claim 6, the first positive electrode active material comprises material A, and the second positive electrode active material comprises a lithium-rich manganese-based material, forming a positive electrode sheet. Claim 8 In claim 6, the first positive active material comprises at least one of material B and material C, and the second positive active material comprises a positive sheet comprising lithium manganese iron phosphate. Claim 9 In claim 6, the volume average particle size Dv50 of the lithium-rich manganese-based material is 10 μm to 20 μm; and / or, the BET specific surface area of ​​the lithium-rich manganese-based material is 0.2 m 2 / g to 1m 2 Anode sheet with a g content. Claim 10 In claim 6, the volume average particle size Dv50 of the lithium manganese iron phosphate is 0.2 μm to 1.5 μm; and / or, the BET specific surface area of ​​the lithium manganese iron phosphate is 10 m² 2 / g to 30m 2 Anode sheet with a g content. Claim 11 A method for manufacturing an anode sheet according to claim 1, comprising the steps of: forming a first anode active material layer containing a first anode active material on at least one side of a current collector; and forming a second anode active material layer containing a second anode active material on one side of the first anode active material layer far from the current collector to obtain an anode sheet. Claim 12 A battery comprising an anode sheet according to any one of claims 1 to 10 or an anode sheet manufactured by the method according to claim 11. Claim 13 A vehicle including a battery pursuant to Paragraph 12.

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