High-voltage positive pole piece and lithium ion secondary battery comprising same

A technology of positive electrode and positive current collector, which is applied in the field of high-voltage positive electrode and lithium ion secondary battery containing the positive electrode, can solve the problems of battery fire, combustion, battery thermal runaway, etc., and improve the stability of performance. , improve safety performance, improve the effect of cycle performance

Inactive Publication Date: 2021-05-28
ZHUHAI COSMX BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the mainstream positive active materials for high-voltage lithium-ion secondary batteries cannot avoid safety accidents in the case of battery abuse. If the temperature rises, the battery is likely to catch fire, burn and other safety accidents
At the same time, higher energy density will also increase the risk of thermal runaway of the battery

Method used

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  • High-voltage positive pole piece and lithium ion secondary battery comprising same
  • High-voltage positive pole piece and lithium ion secondary battery comprising same
  • High-voltage positive pole piece and lithium ion secondary battery comprising same

Examples

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preparation example Construction

[0056] As previously mentioned, the present invention also provides a method for preparing the above-mentioned positive electrode sheet for lithium-ion secondary batteries, comprising the following steps:

[0057] (1) Prepare the following mixed slurry:

[0058] Mix and disperse lithium cobaltate, conductive agent and binder in an organic solvent uniformly to obtain mixed slurry S1; or,

[0059] Mix and disperse uniformly lithium iron manganese phosphate, a conductive agent and a binder in an organic solvent to obtain a mixed slurry S2; or,

[0060] Mix lithium iron manganese phosphate, lithium cobaltate, conductive agent and binder in an organic solvent and disperse uniformly to obtain mixed slurry S3;

[0061] (2) Prepare the following positive pole pieces:

[0062] Coating the mixed slurry S1 on both sides of the positive electrode current collector to make the positive electrode sheet P1; or,

[0063] Coating the mixed slurry S2 on both sides of the positive electrode c...

preparation example 1

[0093] Mix the positive electrode active material LCO, the binder PVDF, and the conductive agent according to the mass ratio of 97wt%: 1.5wt%: 1.5wt%, and disperse them in N-methylpyrrolidone to make the positive electrode active material slurry S1, the slurry The solid content in is 70wt%. Apply the slurry S1 evenly on both sides of the aluminum foil, dry it under high temperature and vacuum at 100-120°C for 14 hours, and compact it with a roller press to 4.05g / cm 3 , the obtained positive pole piece is denoted as P1, and the thickness of the positive pole piece is 0.100mm.

preparation example 2

[0095] Mix the positive electrode active material LMFP, the binder PVDF, and conductive carbon black according to the mass ratio of 93.5wt%: 3.5wt%: 3.0wt%, and disperse them in N-methylpyrrolidone to make the positive electrode active material slurry S2 , the solid content in the slurry was 48wt%. Apply the slurry S2 evenly on both sides of the aluminum foil, dry it in vacuum at a high temperature of 100-120°C for 14 hours, and compact it with a roller press to 3.2g / cm 3 , the obtained positive pole piece is denoted as P2, and the thickness of the positive pole piece is 0.124 mm.

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Abstract

The invention relates to a high-voltage positive pole piece and a lithium ion secondary battery comprising the same. A positive active material in the positive pole piece comprises lithium ferric manganese phosphate (LMFP) and lithium cobalt oxide (LCO), and the lithium ferric manganese phosphate accounts for more than 10 wt% and less than or equal to 65 wt% of the positive active material. The lithium cobalt oxide and the lithium iron manganese phosphate are mixed, so that the stability of the lithium cobalt oxide in a high-voltage system can be effectively improved, and the safety performance of a battery can be improved; although the lithium ferric manganese phosphate has relatively low compaction density and gram volume, the lithium ferric manganese phosphate is mixed with the high-voltage lithium cobalt oxide, and the energy density of the system is not lost; besides, lithium ferric manganese phosphate has excellent cycle performance and is slow in attenuation, so that the cycle performance of the lithium ferric manganese phosphate can be effectively improved by doping the lithium ferric manganese phosphate into a high-voltage system.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion secondary batteries, and in particular relates to a high-voltage positive pole piece and a lithium-ion secondary battery containing the positive pole piece. Background technique [0002] In recent years, with the rapid development of science and technology, lithium-ion secondary batteries have been widely used in mobile communication tools, cameras, notebooks and other portable batteries due to their advantages such as high energy density, long cycle life, no memory effect, clean and pollution-free In electronic equipment, however, with the continuous improvement of human demand for batteries, the safety performance and thermal stability of batteries have gradually become the biggest obstacle affecting the development of batteries to higher energy densities. [0003] At present, the polymer lithium-ion secondary batteries commonly seen on the market are mainly composed of positive electrodes, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/525H01M4/58H01M4/131H01M4/136H01M4/1391H01M4/1397H01M10/0525
CPCH01M4/131H01M4/136H01M4/1391H01M4/1397H01M4/364H01M4/525H01M4/5825H01M10/0525H01M2004/028Y02E60/10
Inventor 樊亚楠李素丽李俊义徐延铭
Owner ZHUHAI COSMX BATTERY CO LTD
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