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A kind of preparation method of lithium battery diaphragm

A lithium battery separator and base film technology, applied in battery pack parts, circuits, electrical components, etc., can solve problems such as reducing battery performance, and achieve the effects of improving stability, improving bonding strength, and reducing thermal shrinkage.

Active Publication Date: 2019-08-20
杨晓丽
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although increasing the amount of glue can increase the adhesion between the coating and the base film, excessive glue will cause the original pores of the base film to be blocked, thereby reducing the performance of the battery.

Method used

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  • A kind of preparation method of lithium battery diaphragm
  • A kind of preparation method of lithium battery diaphragm
  • A kind of preparation method of lithium battery diaphragm

Examples

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Effect test

preparation example Construction

[0034] In order to illustrate the preparation method of the present invention more clearly, the preparation process of the lithium battery separator provided by the present invention is briefly described below in conjunction with specific examples. However, it should be noted that the specific examples provided in the present invention are only preferred examples of the preparation process claimed in the present invention, and will not form any limitation on the scope of protection claimed in the present invention.

[0035] 1. Preparation of lithium battery separator

Embodiment 1

[0037] Step 1, preparing base film and coating slurry.

[0038] 30 parts by weight of ultra-high molecular weight polyethylene with a molecular weight of 1.5 million, paraffin oil of 70 parts by weight, tetrakis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] of 0.3 parts by weight The pentaerythritol ester was fully mixed and then extruded through a twin-screw extruder at an extrusion temperature of 200° C. and a cooling roll temperature of 20° C. to obtain a base film body with a thickness of 1400 μm. Then use a stretching machine to stretch 5 times longitudinally, and the temperature of the longitudinal stretching machine is a gradient change. Then it was stretched 8 times in the transverse direction, and the temperature of the transverse stretching machine was 125°C. The stretched base film is introduced into the extraction tank, fully contacted with the extractant dichloromethane in the extraction tank to extract the pore-forming agent, and the wet base film is ob...

Embodiment 2

[0047] Step 1, preparing base film and coating slurry.

[0048] 25 parts by weight of ultra-high molecular weight polyethylene with a molecular weight of 1.5 million, paraffin oil of 75 parts by weight, tetrakis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] of 0.3 parts by weight The pentaerythritol ester was fully mixed and then extruded through a twin-screw extruder at an extrusion temperature of 200° C. and a cooling roll temperature of 20° C. to obtain a base film body with a thickness of 1400 μm. Then use a stretching machine to stretch 5 times longitudinally, and the temperature of the longitudinal stretching machine is a gradient change. Then it was stretched 8 times in the transverse direction, and the temperature of the transverse stretching machine was 125°C. The stretched base film is introduced into the extraction tank, fully contacted with the extractant dichloromethane in the extraction tank to extract the pore-forming agent, and the wet base film is obt...

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Abstract

The invention provides a method for preparing a lithium battery separator, the method for preparing the lithium battery separator comprises preparing aqueous slurry in two steps; coating a base film with the prepared aqueous slurry, and drying at a low temperature to a constant weight; and obtaining the lithium battery separator after high temperature treatment and crosslinking. The peeling strength of the lithium battery separator is greatly improved, the adhesion between a coating layer and the base film is improved, the heat resistance of the lithium battery separator is effectively improved, the heat shrinkage rate of the lithium battery separator is reduced, and the safety problem due to the heat shrinkage of the lithium battery separator during use can be avoided. Moreover, the gas permeability of the lithium battery separator is not affected, and even slightly improved, and the smooth passage of ions during the use of a lithium battery can be ensured.

Description

Technical field [0001] The invention belongs to the field of lithium battery separators, and relates to a method for preparing a lithium battery separator, and in particular to a method for preparing a lithium battery separator that can improve the adhesion between a base film and a coating. Background technique [0002] In the structure of lithium batteries, the separator is one of its key internal components. The main function of the separator is to separate the positive and negative electrodes of the battery and prevent the two poles from contacting and causing a short circuit. In addition, it also serves as an electrolyte ion channel. Therefore, the performance of the separator determines the interface structure and internal resistance of the lithium battery, and directly affects the battery's capacity, cycle times, safety performance and other characteristics. [0003] Since the electrolyte in the lithium battery structure is an organic system, separator materials that ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/14
CPCH01M50/403Y02E60/10
Inventor 杨晓丽
Owner 杨晓丽
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