Preparation method of lithium-ion battery diaphragm and lithium-ion battery diaphragm

A technology of lithium-ion batteries and diaphragms, which is applied to battery components, circuits, electrical components, etc., can solve the problems of not being able to meet high-rate rapid discharge, decrease in porosity and air permeability, and increase in coating and drying costs. Good through hole, high porosity, avoiding the effect of process and equipment

Active Publication Date: 2015-07-08
SHENZHEN ZHONGXING NEW MATERIAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

On this basis, many patents at home and abroad disclose that the surface of single-layer PP and PE is coated with high-temperature-resistant inorganic coating or high-temperature-resistant organic matter, which in turn will cause some micropores to be blocked and cause porosity and air permeability to decrease, satisfying There is no need for high-rate rapid discharge, and more coating and drying processes and equipment lead to increased costs, and, during processing and use, some inorganic particles will fall off from the base film, resulting in a series of safety issues

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0021] The preparation method of the new lithium-ion battery diaphragm provided by the application solves this technical problem well. In this method, the inorganic particles are first added to the organic solvent and stirred to make a suspension of the inorganic particles, and then the inorganic particles are added Add extrusion-grade PVDF resin to the suspension, stir and mix to make a mixed slurry, directly extrude the mixed slurry into a base film, and then use conventional heat treatment, stretching and other steps to stretch the base film into a porous film , namely the lithium-ion battery separator of the present application. Wherein the stirring speed is 100-300rpm / min, and the stirring speed is carried out from slow to fast.

[0022] It should be noted that the stirring speed is carried out from slow to fast, which means in this application that the stirring speed when adding inorganic particles is lower than the stirring speed after adding PVDF resin, that is to say,...

Embodiment 1

[0026] Weigh 30 parts of dimethylacetamide organic solvent, 50 parts of extrusion-grade PVDF resin, 19 parts of silica particles, and 1 part of silane-based 550 dispersant; first add the organic solvent and 550 dispersant to the stirring tank and mix for 30 minutes , the stirring speed is 200rpm / min; then add the silica particles into the stirring tank, and stir and mix at 200rpm / min for 30 minutes; then add extrusion-grade PVDF resin, and stir and mix at 300rpm / min for 1 hour to prepare the mixed slurry; The mixed slurry was extruded and casted at 200°C to obtain the base film; then the base film was heat-treated in an oven at 120°C for 1 hour, and finally cold-drawn, hot-drawn and heat-set at high temperature to obtain a microporous film, which is the lithium-ion battery in this example diaphragm. In this example, during the high-temperature heat setting stage, the volatilized organic solvent can also be condensed and recycled.

[0027] The lithium-ion battery separator pre...

Embodiment 2

[0029] Weigh 40 parts of N,N-dimethylformamide organic solvent, 40 parts of extrusion-grade PVDF resin, 19 parts of silica particles, and 1 part of silane-based 550 dispersant; first add the organic solvent and 550 dispersant and stir Kettle, stirring and mixing at 150rpm / min for 30 minutes; then adding silica particles into the stirring tank, stirring and mixing at 150rpm / min for 30 minutes; then adding PVDF resin, stirring and mixing at 250rpm / min for 1 hour to obtain a mixed slurry; The slurry was extruded and casted at 180°C to obtain a base film, and then the base film was heat-treated in an oven at 120°C for 1 hour, and finally cold-drawn, hot-drawn, and heat-set at a high temperature to obtain a microporous film, that is, the lithium ion film of this example. battery separator. In the high-temperature heat setting stage, the volatilized organic solvent can be condensed and recycled.

[0030] The lithium-ion battery separator prepared in this example not only has a high...

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Abstract

The invention discloses a preparation method of a lithium-ion battery diaphragm and the lithium-ion battery diaphragm prepared by the preparation method. The preparation method of the lithium-ion battery diaphragm comprises the following steps: adding inorganic particles and extruded-grade PVDF (Polyvinylidene Fluoride) resin into an organic solvent in sequence; and agitating uniformly to prepare mixed slurry and extruding the mixed slurry to form a base film, wherein the agitating speed is 100-300rpm / min and the agitating speed is carried out from slow to fast. The lithium-ion battery diaphragm prepared by the method disclosed by the invention not only can reach higher high-temperature-resisting performance, but also does not influence the porosity and does not influence the diaphragm forming performance and the machining performance of the diaphragm. The preparation method disclosed by the invention is simple and convenient to operate; and compared with a method for coating an inorganic particle layer on the surface of the battery diaphragm, the preparation method has the advantages that extra procedures and equipment are not needed, and a series of safety problems caused by the falling of the inorganic particles of a coating are avoided.

Description

technical field [0001] The present application relates to the field of battery separators, in particular to a method for preparing a lithium-ion battery separator and a lithium-ion battery separator prepared by the method. Background technique [0002] With the continuous development of lithium-ion batteries and the diversification of battery technology, especially power vehicles and large-capacity energy storage batteries have put forward high requirements for lithium battery separators in order to achieve high-rate rapid discharge. The high porosity and through-holes also put forward high requirements for high temperature resistance, so traditional single-layer polyolefin battery separators, such as PP film and PE film, cannot meet the high temperature resistance performance. On this basis, many patents at home and abroad disclose that the surface of single-layer PP and PE is coated with high-temperature-resistant inorganic coating or high-temperature-resistant organic mat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B29D7/01H01M2/16
CPCY02E60/10
Inventor 于长溥张羽标
Owner SHENZHEN ZHONGXING NEW MATERIAL TECH CO LTD
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