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CN-121983510-A - Positive plate, preparation method thereof and battery

CN121983510ACN 121983510 ACN121983510 ACN 121983510ACN-121983510-A

Abstract

The embodiment of the application discloses a positive plate, a preparation method thereof and a battery, and belongs to the technical field of batteries. The heat conduction layer is arranged on at least one side of the positive current collector, and comprises a first electric conduction agent and a heat conduction adhesive, wherein the heat conduction adhesive comprises boron nitride modified polyacrylic acid. The positive electrode active layer is arranged on one side of the heat conduction layer, which is away from the positive electrode current collector. According to the positive plate provided by the application, the first conductive agent and the heat-conductive adhesive in the heat-conductive layer are cooperatively matched, so that on the basis of ensuring good bonding performance and electric conductivity between the positive electrode active layer and the current collector, the heat-conductive capability of the positive plate is obviously improved, the local and whole temperature rise of the battery in the charge and discharge process is reduced, and the quick charge performance and safety of the lithium ion battery are ensured.

Inventors

  • Kuang Kunbin
  • HONG SIFAN
  • LIU RONGJIANG
  • WU YONGXUAN

Assignees

  • 惠州亿纬锂能股份有限公司

Dates

Publication Date
20260505
Application Date
20251224

Claims (10)

  1. 1. A positive electrode sheet, comprising: A positive electrode current collector (10); The heat conduction layer (20) is arranged on at least one side of the positive electrode current collector (10), the heat conduction layer (20) comprises a first electric conduction agent and a heat conduction adhesive, and the heat conduction adhesive comprises boron nitride modified polyacrylic acid; and the positive electrode active layer (30), wherein the positive electrode active layer (30) is arranged on one side of the heat conduction layer (20) away from the positive electrode current collector (10).
  2. 2. Positive plate according to claim 1, characterized in that the thickness of the positive current collector (10) is 8-15 μm; and/or the thickness of the heat conducting layer (20) is 1-5 μm; and/or the positive electrode active layer (30) has a thickness of 30 μm to 100 μm.
  3. 3. The positive plate according to claim 1, wherein in the boron nitride modified polyacrylic acid, the mass percentage of boron nitride is 1% -15%; And/or the number average molecular weight of the boron nitride modified polyacrylic acid is 100000-300000; And/or, the boron nitride in the boron nitride modified polyacrylic acid comprises at least one of hexagonal boron nitride, cubic boron nitride and spherical boron nitride; And/or the grain diameter D50 of the boron nitride is less than or equal to 3 mu m.
  4. 4. The positive electrode sheet according to claim 1, wherein the heat conductive layer (20) further includes therein a heat conductive filler including at least one of graphene and carbon nanotubes.
  5. 5. The positive plate according to claim 4, wherein the mass ratio of the thermally conductive adhesive, the thermally conductive filler, and the first electrically conductive agent in the thermally conductive layer (20) is (60% -70%) (10% -15%) (15% -30%); And/or the heat-conducting filler comprises graphene and carbon nano tubes, wherein the mass ratio of the graphene to the carbon nano tubes in the heat-conducting filler is (1-2); And/or the first conductive agent includes at least one of carbon black, acetylene black, ketjen black, and graphite.
  6. 6. The positive electrode sheet according to any one of claims 1 to 5, wherein the positive electrode active layer (30) includes therein a positive electrode active material, a binder, and a second conductive agent; The positive electrode active material includes at least one of lithium cobaltate and ternary material; and/or the binder comprises at least one of polyvinylidene fluoride, sodium carboxymethyl cellulose, styrene-butadiene rubber and polyacrylic acid; and/or the second conductive agent includes at least one of carbon black and carbon nanotubes.
  7. 7. The positive electrode sheet according to claim 6, wherein in the positive electrode active layer (30), the mass ratio of the positive electrode active material, the binder, and the second conductive agent is (92% -96%) (2% -4%); And/or, in the second conductive agent, the mass ratio of the carbon black to the carbon nano tube is (3-5): 1.
  8. 8. The preparation method of the positive plate is characterized by comprising the following steps: Providing a positive electrode current collector (10); Providing a heat conduction layer (20) slurry comprising a first electric conduction agent and a heat conduction binder, and coating the heat conduction layer (20) slurry on at least one side surface of the positive electrode current collector (10) to form a heat conduction layer (20), wherein the heat conduction binder comprises boron nitride modified polyacrylic acid; Providing positive electrode active layer (30) slurry, coating the positive electrode active layer (30) slurry on one side surface of the heat conduction layer (20) away from the positive electrode current collector (10) to form a positive electrode active layer (30), and obtaining a positive electrode plate.
  9. 9. The method for preparing a positive electrode sheet according to claim 8, characterized in that the method for preparing a boron nitride modified polyacrylic acid comprises: Performing amination modification on boron nitride to obtain aminated boron nitride; Mixing a part of acrylate monomers, an oxidant, an emulsifier and water to obtain a first solution; adding another part of the acrylic ester monomer and the aminated boron nitride into a solvent to obtain a second solution; And mixing the first solution and the second solution, and reacting and drying to obtain the boron nitride modified polyacrylic acid.
  10. 10. A battery comprising the positive electrode sheet according to any one of claims 1 to 7, and/or the positive electrode sheet produced by the positive electrode sheet production method according to any one of claims 8 to 9.

Description

Positive plate, preparation method thereof and battery Technical Field The application relates to the technical field of batteries, in particular to a positive plate, a preparation method thereof and a battery. Background The lithium ion battery is widely applied to the fields of power and consumption, and along with the increasing requirements of the market on the quick charge performance of the battery, the charge rate of most lithium ion batteries reaches more than 3C, and even the average charge speed reaches 6C. The high-rate charging scene provides higher requirements on the heat dissipation performance of the lithium ion battery. In lithium ion batteries, graphite materials are generally used as the negative electrode and metal oxides as the positive electrode. In the battery operation process, the heat conduction capacity of the negative electrode plate is strong, and the heat conduction capacity of the positive electrode plate is weak, so that the heat dissipation performance of the positive electrode plate becomes a bottleneck for limiting the quick charge heat dissipation performance, a mode capable of effectively improving the heat conduction coefficient of the positive electrode plate is required to be sought, so that the local and whole temperature rise of the battery in the charge and discharge process is reduced, and the quick charge performance and the safety of the lithium ion battery are ensured. Disclosure of Invention The application provides a positive plate, a preparation method thereof and a battery, which can obviously improve the heat conduction capacity of the positive plate, reduce the local and whole temperature rise of the battery in the charge and discharge process and ensure the quick charge performance and the safety of the lithium ion battery on the basis of ensuring the good bonding performance and the electric conduction capacity between a positive active layer and a current collector in the positive plate. According to a first aspect of the present application, there is provided a positive electrode sheet comprising: A positive electrode current collector; The heat conduction layer is arranged on at least one side of the positive current collector, and comprises a first electric conduction agent and a heat conduction adhesive, wherein the heat conduction adhesive comprises boron nitride modified polyacrylic acid; and the positive electrode active layer is arranged on one side of the heat conduction layer, which is away from the positive electrode current collector. The positive plate provided by the application comprises a positive current collector, a heat conducting layer and a positive active layer, wherein the heat conducting layer is arranged between the positive current collector and the positive active layer, the heat conducting layer comprises a first electric conduction agent and a heat conducting adhesive, and the heat conducting adhesive comprises polyacrylic acid modified by boron nitride, so that the heat conducting layer can obviously increase the heat conducting capacity of the positive plate, ensure the bonding performance between the positive active layer and the positive current collector, and ensure good electric conduction performance between the positive active layer and the positive current collector. Namely, the positive plate provided by the application can obviously improve the heat conduction capacity of the positive plate, reduce the local and whole temperature rise of the battery in the charging and discharging process and ensure the quick charging performance and the safety of the lithium ion battery on the basis of ensuring the good bonding performance and the electric conduction capacity between the positive electrode active layer and the current collector through the cooperative matching of the first electric conduction agent and the heat conduction adhesive in the heat conduction layer. Alternatively, the thickness of the positive electrode current collector is 8 μm to 15 μm; and/or the thickness of the heat conducting layer is 1 μm-5 μm; and/or the thickness of the positive electrode active layer is 30 μm to 100 μm. The thickness of the positive electrode current collector is within the above range, so that good mechanical strength and high conductivity can be ensured, and a lightweight design is ensured, thereby contributing to the improvement of energy density. Through the thickness of heat conduction layer in above-mentioned within range, can form high-efficient heat conduction passageway between positive electrode active layer and positive electrode current collector, derive the heat in the charge and discharge process fast, avoid the circumstances such as thermal runaway that local overheated leads to, and the heat conduction layer of thickness is thinner can avoid introducing too much inactive substance in the positive plate, reduce the influence to energy density, the heat conduction layer of thickness is thinner can also reduce t