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Preparation method of negative electrode slurry capable of reducing expansion of lithium ion battery

A lithium-ion battery and negative electrode slurry technology, which is applied to battery electrodes, secondary batteries, circuits, etc., can solve the problems of easy subsidence of slurry, achieve the effects of reducing bridging phenomenon, improving capacity and safety, and inhibiting subsidence

Active Publication Date: 2016-11-23
南京国轩新能源有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, for isotropic artificial graphite, due to the bridging between particles, the slurry is easy to settle, and it is difficult to solve the problem by using traditional binders and slurry mixing methods.

Method used

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  • Preparation method of negative electrode slurry capable of reducing expansion of lithium ion battery
  • Preparation method of negative electrode slurry capable of reducing expansion of lithium ion battery
  • Preparation method of negative electrode slurry capable of reducing expansion of lithium ion battery

Examples

Experimental program
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Effect test

Embodiment 1

[0025] The negative electrode active material is made of isotropic pure artificial graphite through secondary granulation, the binder is modified SBR binder, the conductive agent is conductive carbon black Sp, the glue is CMC aqueous solution, and the modified SBR binder is in The mass percent content in the negative electrode slurry is 3%.

[0026] Negative electrode slurry preparation comprises the following steps: (1) pre-dry mixing artificial graphite and conductive carbon black Sp; (2) sodium carboxymethylcellulose is dissolved in deionized water to obtain a CMC glue solution with a concentration of 1.0%; (3) ) Add 10% of the CMC glue prepared in (2) into the mixture, set the rotation speed at 4000rpm, the revolution speed at 64rpm, and stir for 0.5h; (4) add the remaining 90% of the CMC glue, and set the rotation speed at 4000rpm , revolution speed 64rpm, stirring for 3h; (5) Add modified SBR binder, set rotation speed 2000rpm, revolution speed 40rpm, stir for 0.3h; (6) ...

Embodiment 2

[0040] In this embodiment, the negative electrode active material is made of isotropic pure artificial graphite through secondary granulation, the binder is modified SBR, the mass percentage content of modified SBR in the negative electrode slurry is 1%, and the conductive agent is conductive carbon. Black, glue solution is CMC aqueous solution.

[0041]The negative electrode slurry preparation comprises the following steps: (1) pre-dry mixing artificial graphite and conductive carbon black; (2) dissolving sodium carboxymethyl cellulose in deionized water to obtain a CMC glue solution with a concentration of 2.0%; (3) Add 35% of the CMC glue prepared in (2) into the mixture, set the rotation speed at 4000rpm, the revolution speed at 64rpm, and stir for 1h; (4) add the remaining 65% of the glue, set the rotation speed at 2500rpm, and the revolution speed 40rpm, stir for 1h; (5) Add hydroxylated SBR, stir at a medium speed, set the rotation speed at 2000rpm, revolution speed at ...

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Abstract

The invention discloses a preparation method of negative electrode slurry capable of reducing the expansion of a lithium ion battery. The preparation method comprises the following steps of: carrying out dry blending on a negative electrode active substance and a conducting agent in advance; dissolving sodium carboxymethyl cellulose into de-ionized water to obtain a CMC (Carboxyl Methyl Cellulose) gel solution with the concentration of 1.0%-2.0%; adding one part of the CMC gel solution into a mixture of the negative electrode active substance and the conducting agent and stirring at a high speed for 0.5-1h; adding the balance of CMC gel solution and stirring at a high speed for 1-3h; adding a modified SBR (Styrene Butadiene Rubber) binding agent and stirring at a middle speed for 0.3-1h; and adjusting the viscosity. By adopting the method of carrying out the dry blending on artificial graphite and the conducting agent in advance, adding the glue solution by two times and utilizing modified SBR as the binding agent, a bridge phenomenon of the artificial graphite is reduced, a pole piece structure is changed, the binding force between grains is improved and the expansion of a negative electrode is reduced; meanwhile, the slurry sedimentation of the artificial graphite is inhibited. The preparation method of the negative electrode slurry capable of reducing the expansion of the lithium ion battery has important meanings on ternary lithium ion batteries and improvement of machinability, capacity and safety of high-capacity power batteries.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a method for preparing negative electrode slurry for reducing the expansion of lithium ion batteries. Background technique [0002] High-capacity ternary batteries have higher requirements for negative electrode materials, such as high capacity, high compaction, and low rebound. The high rebound rate of the negative electrode material makes the square aluminum shell battery hard and swollen, resulting in the appearance of the battery product not meeting the standard, which has become one of the problems that the lithium battery industry needs to solve urgently. [0003] Square aluminum shell batteries on the market often bulge after high-temperature storage and cycling, and the thickness increases by 6-20%. Among them, the expansion rate of the positive electrode is 4%, and the expansion rate of the negative electrode is more than 20%. Therefore, it is believed that...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/583H01M4/62H01M10/0525
CPCH01M4/583H01M4/621H01M4/625H01M10/0525Y02E60/10
Inventor 贺雨雨冯德圣陈炜张宏立
Owner 南京国轩新能源有限公司
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