CN-122025546-A - Pole piece, battery and pole piece preparation process

Abstract

The application relates to a pole piece, a battery and a pole piece preparation process, and relates to the technical field of lithium ion batteries. The pole piece includes a current collector and an active layer. The current collector is used for charge collection conduction. The active layer comprises a double conductivity additive comprising a matrix layer and a cladding layer, wherein the matrix layer is provided as a lithium-containing compound and the cladding layer is provided as an electronically conductive material. The pole piece provided by the application can improve the performance of the battery in a low-temperature environment, slow down the capacity attenuation rate of the battery in the low-temperature environment, and improve the multiplying power and the recycling service life of the battery.

Inventors

• ZHAO DUAN
• CHEN BINHUA
• ZHANG BIN
• HUANG HAINING

Assignees

• 兰钧新能源科技有限公司

Dates

Publication Date

20260512

Application Date

20260317

Claims (10)

1. 1. A pole piece, the pole piece comprising: A current collector for charge collection conduction; An active layer comprising a double conductivity additive comprising a matrix layer and a cladding layer, wherein the matrix layer is provided as a lithium-containing compound and the cladding layer is provided as an electronically conductive material.
2. 2. The pole piece of claim 1, wherein the lithium-containing compound is provided as porous lithium metaaluminate.
3. 3. The pole piece of claim 1, wherein the electronically conductive material is provided as any one of carbon nanotubes, porous graphene, and conductive carbon black.
4. 4. A pole piece according to any of claims 1-3, characterized in that the mass ratio of the lithium containing compound and the electronically conductive material is 200:1.
5. 5. A pole piece according to any of claims 1-3, characterized in that the active layer further comprises an active substance, a binder and a dispersing agent.
6. 6. A pole piece according to any of claims 1-3, characterized in that the pole piece is a positive pole piece or a negative pole piece.
7. 7. A battery, the battery comprising: A housing, and A pole piece according to any of claims 1-6, being processed to form a winding core structure, the winding core structure being disposed within the housing.
8. 8. A pole piece manufacturing process suitable for manufacturing a pole piece according to any of claims 2-6, characterized in that the pole piece manufacturing process comprises the steps of: Preparing a lithium-containing compound, namely dissolving lithium nitrate serving as a raw material in deionized water, adding porous alumina, stirring, standing and freezing the material, and sintering the frozen material to obtain porous lithium metaaluminate; Preparing a double-conductivity additive, namely mixing and stirring porous lithium metaaluminate and carbon nano tubes according to the mass ratio of 200:1, standing, removing supernatant fluid, washing, dispersing a washed sample in a solution, and then freeze-drying to obtain the double-conductivity additive of the carbon nano tube coated porous lithium metaaluminate; The preparation of the pole piece comprises the steps of mixing a double-conductivity additive, an active substance, an adhesive and a dispersing agent in proportion to prepare active slurry, coating the active slurry on a current collector to form an active layer, and rolling, slitting and die cutting to prepare the pole piece.
9. 9. The process for preparing a pole piece according to claim 8, wherein the porous alumina is prepared by adding a solution from boehmite as a raw material to obtain a hydrated alumina solution, adding chitin and pluronic 123 into isopropanol according to a weight ratio of 4:1, stirring and dissolving, adding urea and stirring to obtain an intermediate solution, adding the hydrated alumina solution into the intermediate solution and heating for reaction, cooling the product to room temperature, removing the supernatant, washing and drying, and finally calcining at 700 ℃ to obtain the porous alumina.
10. 10. The process for preparing a pole piece according to claim 8, wherein in the step of preparing the double conductivity additive, before mixing the porous lithium metaaluminate and the carbon nanotubes, the carbon nanotubes and the dispersing agent are mixed and placed in deionized water to obtain a carbon nanotube dispersion, and then the carbon nanotube dispersion is mixed with the porous lithium metaaluminate.

Description

Pole piece, battery and pole piece preparation process Technical Field The application relates to the technical field of lithium ion batteries, in particular to a pole piece, a battery and a pole piece preparation process. Background As the application of lithium ion batteries is becoming wider, different performance requirements are also being put forward for lithium ion batteries for different use environments. When the lithium ion battery is applied to a low-temperature environment, the viscosity of the electrolyte is increased due to low temperature, meanwhile, the conductivity is reduced, so that the impedance of the lithium ion battery is increased, the migration rate of lithium ions in an active substance is reduced, and further, the lithium ions are difficult to deintercalate, so that the internal resistance is increased, and the capacity is rapidly reduced. In addition, the deintercalation rate of lithium ion reduces, still probably leads to the inhomogeneous deposition of lithium ion at the pole piece, and then takes place pole piece surface and deposit lithium, not only can reduce the security of battery, can also seriously influence the performance and the life of battery. In the prior art, in order to solve the above problems, improvements are generally made from the aspects of improving the conductivity of the electrolyte, improving the dynamic performance of the active material, or reducing the impedance. The improvement of the low-temperature conductivity of the electrolyte can affect the cycle life, multiplying power and other performances of the lithium ion battery, and the improvement of the dynamic performance of the active material is optimized for the active material, so that the process is complex and the adaptability is single. The alternative scheme for reducing the impedance is to increase the lithium ion conductivity or the electron conductivity of the pole piece by adding the conductive material during the preparation of the pole piece, but the problem of single function improvement exists, and the improvement of the conductivity of lithium ions and electrons cannot be considered. Therefore, it is desirable to provide a lithium ion battery, which can solve the above problems, improve the performance of the battery in a low-temperature environment, slow down the capacity fade rate of the battery in a low-temperature environment, and improve the multiplying power and the cycle life of the battery. Disclosure of Invention The application aims to provide a pole piece, a battery and a pole piece preparation process, which can solve the problems, improve the performance of the battery in a low-temperature environment, slow down the capacity attenuation rate of the battery in the low-temperature environment and improve the multiplying power and the recycling service life of the battery. In order to achieve the above object, the present application provides, in a first aspect, a pole piece. The pole piece includes a current collector and an active layer. The current collector is used for charge collection conduction. The active layer comprises a double conductivity additive comprising a matrix layer and a cladding layer, wherein the matrix layer is provided as a lithium-containing compound and the cladding layer is provided as an electronically conductive material. Based on the above embodiment of the present application, when the battery is applied to a low-temperature environment, the low-temperature environment affects the performance of the battery, and on one hand, the low temperature can cause the viscosity of the electrolyte to increase, thereby causing the migration rate of lithium ions to decrease and the internal resistance of the battery to increase. On the other hand, in the anode and cathode materials, the temperature drop results in a slow diffusion rate of lithium ions, and at the same time, the impedance at the electrode/electrolyte interface increases, resulting in a more difficult crossing of lithium ions across the interface. With the above arrangement of the present application, by adding a double conductivity additive in the active layer of the pole piece, it specifically comprises a lithium-containing compound as a matrix layer and an electron conductivity material as a cladding layer. Wherein the lithium-containing compound has good lithium ion conductivity. The electron conductive material has good electron conductivity. By compounding the two additives, a double-conductivity additive having both good lithium ion conductivity and electron conductivity is obtained. The bipolar conductive additive is added into the active layer of the pole piece, so that the electron conductivity and lithium ion conductivity of the pole piece are improved, the interface film impedance and the charge transfer impedance are effectively reduced, and the lithium ion and electron conductivity under the low-temperature condition is enhanced, so that the performance of the battery under th