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Lithium ion battery negative plate, preparation method thereof and lithium ion battery

A lithium-ion battery and negative electrode technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of unfavorable cell rate discharge performance, low-temperature charge-discharge performance and long-term cycle performance, weak affinity with electrolyte, The problem of poor liquid absorption effect of the pole piece can achieve the effect of improving the rate charge and discharge performance, reducing the conductivity and increasing the affinity.

Active Publication Date: 2020-02-21
东莞维科电池有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, SBR is a small molecular linear chain emulsion, which is easily dispersed in water and polar solvents, while the lithium-ion battery electrolyte is a non-aqueous organic solvent, so the chemical structure and properties of SBR itself determine its affinity with the electrolyte It is not strong, which leads to poor liquid absorption effect of the pole piece and small liquid storage in the battery cell, which is not conducive to the rate discharge performance, low temperature charge and discharge performance and long-term cycle performance of the battery cell.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] (1) Negative plate preparation: According to the solid weight ratio, graphite (C): conductive agent (SP): acrylic acid polymer is mixed according to the ratio of 96.9%: 0.5%: 2.6%, and a uniformly dispersed negative electrode slurry is obtained by high-speed stirring , the negative electrode slurry is evenly coated on both sides of the copper foil, and the negative electrode sheet is obtained through drying, rolling and cutting. The negative electrode slurry is evenly coated on both sides of the copper foil, and the negative electrode sheet is obtained after drying, rolling, and cutting. Among them, the relative molecular mass of the dispersant is 500-5000, the relative molecular mass of the binder is 5000-1,000,000, the relative molecular mass of the thickener is greater than 1,000,000, the dispersant acrylic polymer, the binder acrylic polymer and the thickener The mass percent of the agent acrylic acid polymer is 0.3%: 1.3%: 1.0%.

[0022] (2) Positive plate prepara...

Embodiment 2

[0026] Different from Example 1 is the preparation of negative electrode sheet:

[0027] According to the solid weight ratio, graphite (C): conductive agent (SP): acrylic acid polymer is mixed according to the ratio of 96.9%: 0.5%: 2.6%, and a uniformly dispersed negative electrode slurry is obtained by high-speed stirring, and the negative electrode slurry is evenly coated. On both sides of the copper foil, the negative electrode sheet is obtained through drying, rolling, and slitting. The negative electrode slurry is evenly coated on both sides of the copper foil, and the negative electrode sheet is obtained after drying, rolling, and cutting. Among them, the relative molecular mass of the dispersant is 500-5000, the relative molecular mass of the binder is 5000-1,000,000, the relative molecular mass of the thickener is greater than 1,000,000, the dispersant acrylic polymer, the binder acrylic polymer and the thickener The mass percentage of the agent acrylic acid polymer i...

Embodiment 3

[0030] Different from Example 1 is the preparation of negative electrode sheet:

[0031] According to the solid weight ratio, graphite (C): conductive agent (SP): acrylic acid polymer is mixed according to the ratio of 96.9%: 0.5%: 2.6%, and a uniformly dispersed negative electrode slurry is obtained by high-speed stirring, and the negative electrode slurry is evenly coated. On both sides of the copper foil, the negative electrode sheet is obtained through drying, rolling, and slitting. The negative electrode slurry is evenly coated on both sides of the copper foil, and the negative electrode sheet is obtained after drying, rolling, and cutting. Wherein, the mass percent of dispersant acrylic polymer, binder acrylic polymer and thickener acrylic polymer is 0.5%: 1.3%: 0.8%.

[0032] The rest are the same as in Embodiment 1, and will not be repeated here.

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PUM

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Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a lithium ion battery negative plate. The lithium ion battery negative plate comprises a negative current collector and a negative active material layer coated on the surface of the negative current collector. The negative active material layer comprises a negative active material, a conductive agent, a dispersing agent, a binding agent and a thickening agent. The dispersing agent, the binding agent and the thickening agent are acrylic polymers of which the relative molecular masses are sequentially increased respectively. According to the invention, the dispersing agent sodium carboxymethyl cellulose, the binding agent styrene butadiene rubber and the thickening agent sodium carboxymethyl cellulose are changed into acrylic polymers with sequentially increased relative molecular mass respectively; the affinity of the negative active material layer to an electrolyte is improved, which facilitates the conduction of metal ions, and promotes the transmission of lithium ions in an electrode-electrolyte interface; the rate charge-discharge performance of the lithium ion battery is improved;besides, under a low-temperature condition, the acrylic polymers can accelerate the transmission of lithium ions by improving the affinity to the electrolyte; and the low-temperature 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 negative plate, a preparation method thereof, and a lithium ion battery. Background technique [0002] Lithium-ion batteries have gradually conquered the application market of various energy storage batteries due to their excellent performance such as high energy density, high working voltage, and long cycle life, and have changed people's lives. The traditional 3C field has shown that the lithium-ion battery is the only one, and the emerging fields such as electric vehicles, smart grids, and distributed energy storage have provided new opportunities and challenges for the development of lithium-ion batteries. [0003] A lithium-ion battery is mainly composed of a positive electrode, a negative electrode, a separator, and an electrolyte solution between them. The positive electrode and the negative electrode include materials that c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/133H01M4/62H01M4/1393H01M10/0525
CPCH01M4/133H01M4/62H01M4/622H01M4/1393H01M10/0525Y02P70/50
Inventor 葛鸽付奥张爱莲孙梦婷朱坤庆计阳夏小勇陶德瑜
Owner 东莞维科电池有限公司
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