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Lithium ion battery positive pole piece and preparation method thereof

A lithium-ion battery and cathode electrode technology, which is applied to battery electrodes, non-aqueous electrolyte battery electrodes, batteries, etc., can solve the problems of low PTC effect and reduce the rate performance of lithium-ion batteries, and achieve the improvement of crystallinity and room temperature conductivity. performance, contact-promoting effect

Inactive Publication Date: 2021-04-23
SHENZHEN GPC ENERGY GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, at this stage, the PTC coating used on the positive electrode sheet has a low PTC effect and reduces the rate performance of lithium-ion batteries. Therefore, it is urgent to develop a method that can improve the PTC effect without affecting the rate performance of lithium-ion batteries. Break the internal short-circuit reaction of the battery to improve the safety performance of lithium-ion batteries

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0022] The preparation method of the lithium-ion battery positive pole piece comprises the following steps:

[0023] S1: Dissolve the organic polymer in the solvent, then add the conductive agent, stir evenly, add the adhesive, stir and disperse evenly to obtain the PTC slurry;

[0024] S2: Coat the PTC slurry prepared in S1 on the surface of the current collector, and then dry it at 50-100°C, then heat-press the dried PTC sheet at a certain temperature, and then cold-press it to obtain PTC film;

[0025] S3: Stir the positive electrode active material, conductive agent, and binder evenly, coat the surface of the PTC sheet prepared in S2, and dry to obtain a positive electrode sheet with a PTC effect.

Embodiment 1

[0027] S1: Dissolve maleic anhydride-grafted polyethylene in a solvent, then add to carbon nanotubes, stir evenly, add polyacrylonitrile, stir and disperse evenly to obtain PTC slurry;

[0028] S2: Coat the PTC slurry prepared in S1 on the surface of the current collector, and then dry it at 60°C, and then heat-press the dried PTC sheet at 120°C at a pressure of 2Mpa for 10min, and then dry it at 20°C. PTC sheets can be obtained by cold pressing at a pressure of 2Mpa for 10 minutes at a temperature of ℃;

[0029] S3: Stir the positive electrode active material, conductive agent, and binder evenly, coat the surface of the PTC sheet prepared in S2, and dry to obtain a positive electrode sheet with a PTC effect.

Embodiment 2

[0031] S1: Dissolve maleic anhydride-grafted polyethylene in a solvent, then add to carbon nanotubes, stir evenly, add polyacrylonitrile, stir and disperse evenly to obtain PTC slurry;

[0032] S2: Coat the PTC slurry prepared in S1 on the surface of the current collector, and then dry it at 60°C, and then heat-press the dried PTC sheet at 120°C at a pressure of 5Mpa for 10min, and then dry it at 20°C. PTC sheets can be obtained by cold pressing at a pressure of 5Mpa for 10 minutes at a temperature of ℃;

[0033] S3: Stir the positive electrode active material, conductive agent, and binder evenly, coat the surface of the PTC sheet prepared in S2, and dry to obtain a positive electrode sheet with a PTC effect.

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PUM

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Abstract

The invention discloses a lithium ion battery positive pole piece and a preparation method thereof. The lithium ion battery positive pole piece comprises a current collector, a PTC coating and a positive coating; the PTC coating comprises an organic polymer material, a conductive agent and an adhesive. The organic polymer material, the conductive agent, the adhesive and other materials with positive temperature coefficients are adopted to prepare the PTC coating; contact of conductive particles of the coating is promoted through hot pressing and cold pressing, the room-temperature conductivity of the coating is improved, meanwhile, the crystallinity of the materials in the PTC coating is improved, and the PTC effect is improved; and when a lithium ion battery passes overcharging, puncturing, and short-circuit security detection, and when the temperature rises to 80-100 DEG C, the PTC coating is changed into an insulator from a conductor, so that the positive electrode active material is disconnected from a current collector, the short-circuit reaction in the battery is effectively cut off, and the safety performance of the lithium ion battery is improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery positive pole piece and a preparation method thereof. Background technique [0002] Lithium-ion battery is a new generation of high-energy "green" energy after lead-acid, cadmium-nickel, and metal hydride nickel batteries, and its application range is becoming more and more extensive. Especially at the present stage, the development of high-energy-density lithium-ion batteries has become a research and development hotspot of major enterprises. But security has always been a difficult problem to solve. At present, it is mainly to add additives to the electrolyte, such as adding overcharge additives to pass the overcharge test, but the common disadvantage of overcharge protection additives is that their overcharge protection is one-time, and cannot protect the battery for a long time. In addition, ceramic diaphragms are also used to...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/13H01M4/62H01M4/139H01M10/0525
CPCH01M4/13H01M4/139H01M4/628H01M10/0525H01M2004/028H01M2200/30Y02E60/10
Inventor 崔日俊李国敏
Owner SHENZHEN GPC ENERGY GRP CO LTD
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