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A kind of negative electrode composite thickener, negative electrode sheet and preparation method

A technology of composite thickener and negative electrode sheet, which is applied in the direction of negative electrodes, electrode manufacturing, battery electrodes, etc., can solve the problems of negative electrode slurry floating blue, negative electrode rolling surface sticking rolls, etc., to improve the negative electrode adhesion, The effect of improving the problem of sticking rollers and alleviating the problem of SBR floating

Active Publication Date: 2022-03-18
WANXIANG 123 CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the problems of negative electrode slurry floating blue and negative electrode rolling surface sticking rollers in the preparation process of water system CMC-SBR mixed adhesive negative electrode sheet, the present invention provides a method that can alleviate the floating of SBR and effectively improve the negative electrode sheet. Negative composite thickener for sticky rolls during rolling

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] (1) According to the following proportions, based on the total mass of the negative electrode sheet, the negative electrode sheet includes the following components in mass percentage: 95wt% of negative electrode material, 2wt% of conductive carbon black, 3% of negative electrode composite thickener, and Negative electrode material, conductive agent, and negative electrode composite thickener were added to the homogenization tank and stirred once for 1.0h for preliminary mixing, then added deionized water and stirred for a second time for 5 hours to obtain negative electrode slurry; the negative electrode composite thickener was made of carboxymethyl fiber It is prepared by mixing plain sodium and highly substituted guar gum with a substitution degree of 1.6 at a mass ratio of 1:3; (2) adding deionized water and SBR emulsion to the negative electrode slurry and stirring for 1.5 hours for three times, and then coating on the metal copper The surface of the foil was dried a...

Embodiment 2

[0025] (1) According to the following proportioning, based on the total mass of the negative electrode sheet, the negative electrode sheet includes the following components in mass percentage: negative electrode material 94wt%, super conductive carbon black 1.5wt%, carbon nanotube 1.5wt%, Negative electrode composite thickener 3.5%, add the negative electrode material, conductive agent, and negative electrode composite thickener into the homogenization tank and stir for 0.5h for a preliminary mixing, then add deionized water and stir for 6 hours for the second time to obtain the negative electrode slurry; The compound thickener is made by mixing sodium carboxymethyl cellulose and highly substituted guar gum with a substitution degree of 1.2 at a mass ratio of 1:5;

[0026] (2) Add deionized water and SBR emulsion to the negative electrode slurry and stir for 2 hours three times, then coat the surface of metal copper foil and dry at 90°C to obtain the negative electrode sheet. ...

Embodiment 3

[0028] (1) According to the following proportions, based on the total mass of the negative electrode sheet, the negative electrode sheet includes the following components in mass percentages: 94-97wt% of negative electrode material, 0.5wt% of carbon fiber, 1.5% of negative electrode composite thickener, Add the negative electrode material, conductive agent, and negative electrode composite thickener into the homogenization tank and stir for 1.5 hours for a preliminary mixing, then add deionized water and stir for a second time to obtain the negative electrode slurry; the negative electrode composite thickener is composed of carboxymethyl Sodium cellulose is mixed with highly substituted guar gum with a substitution degree of 1.8 at a mass ratio of 1:0.2;

[0029] (2) Add deionized water and SBR emulsion to the negative electrode slurry and stir for three times for 1 hour, then coat the surface of metal copper foil and dry at 140°C to obtain the negative electrode sheet.

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Abstract

The invention relates to the technical field of lithium-ion batteries. In order to solve the problems of negative electrode slurry floating blue and negative electrode rolling surface sticking rollers in the preparation process of water-based CMC‑SBR mixed adhesive negative electrode sheets, a negative electrode composite booster is provided. Thickener, negative electrode sheet and preparation method, the negative electrode composite thickener is prepared by mixing sodium carboxymethyl cellulose and high-substituted guar gum according to the mass ratio of 1: (0.2-5). The invention prepares the negative electrode composite thickener by introducing high-substituted guar gum, and when preparing the negative electrode sheet, it is compounded with SBR emulsion, and utilizes the electropositive cationic group of the high-substituted guar gum and the electronegative carboxyl group on the surface of the SBR The affinity of the group anchors SBR on the thickener, thereby alleviating the problem of SBR floating in the current CMC-SBR adhesive system, improving the problem of sticking rolls when the negative electrode sheet is rolled, and improving the negative electrode adhesion. Improve the electrochemical performance of lithium batteries.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a negative electrode composite thickener, a negative electrode sheet and a preparation method. Background technique [0002] According to the properties of the dispersion medium, negative electrode binders can be divided into oily binders using organic solvents as dispersants and water-based binders using water as dispersants. Traditional oil-based binders have strong rigidity and relatively high production costs, so they are gradually eliminated; compared with oil-based binders, water-based binders are environmentally friendly, cheap and safer to use, so they are now widely used as negative electrode binders The most common water-based negative electrode binder in the current industrial production is the CMC-SBR-based binder. Among them, CMC mainly acts as a thickener, and SBR mainly acts as a bonding agent. [0003] In the prior art, in the process of preparing ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/62H01M4/13H01M4/04H01M4/139H01M10/0525
CPCH01M4/622H01M4/13H01M4/139H01M4/0404H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 赵星星张鹏韩笑李凡群
Owner WANXIANG 123 CO LTD