Coating slurry for lithium battery diaphragm and coating process

Abstract

The invention relates to a coating slurry for a lithium battery diaphragm and a coating process. The coating slurry is prepared from the following components, by weight, 35 to 55 parts of copolymerization emulsion, 25 to 40 parts of a titanium dioxide dispersion liquid, 3 to 6 parts of a dispersing agent, 3 to 5 parts of chlorinated polypropylene and 1 to 4 parts of an adhesive, wherein the copolymerization emulsion is the copolymerization emulsion of tetrahydrofuran acrylate and butyl methacrylate. The coating process comprises the following steps: S1, adding the copolymerization emulsion, the titanium dioxide dispersion liquid and the chlorinated polypropylene into a magnetic stirrer, stirring for 8 to 10min, then adding the dispersing agent, continuing to stir for 45 to 55min, and finally adding the adhesive, and stirring for 25 to 35min so as to prepare a coating primary slurry; S2, carrying out ball milling treatment on the coating primary slurry to prepare a slurry finished product; S3, placing a diaphragm on a coating machine, and coating the surface of the diaphragm with the slurry finished product at a normal temperature; S4, placing the diaphragm in an environment of 42-45 DEG C for vacuum drying treatment to obtain a coating modified microporous membrane; and S5, winding the coating modified microporous membrane to obtain a finished product. Good adhesiveness is achieved between the coating slurry and the diaphragm.

Description

technical field [0001] The invention relates to the technical field of processing lithium-ion battery diaphragm coating materials, in particular to a coating slurry and a coating process for lithium-ion battery diaphragms. Background technique [0002] Lithium-ion battery is a representative of modern high-performance batteries, consisting of four main parts: positive electrode material, negative electrode material, separator, and electrolyte. Among them, the diaphragm is a thin film with a microporous structure, which is a key inner component with technical barriers in the lithium-ion battery industry chain. The performance of the diaphragm determines the interface structure and internal resistance of the battery, which directly affects the capacity and cycle of the battery. As well as safety performance and other characteristics, the separator with excellent performance plays an important role in improving the overall performance of the battery. It plays the following two ...

AI Technical Summary

Problems solved by technology

[0003] The polyolefin microporous membrane has the following defects: the surface is hydrophobic, and the infiltration effect on the electrolyte is not good; the heat shrinkage temperature is not high, and when the temperature reaches above 130°C, there will be different degrees of volume shrinkage and cause internal short circuit

However, as the ceramic particle material is an inorganic material, there is no stress conduction between the particles, which seriously reduces the mechanical strength of the ceramic coating diaphragm, and its compatibility with the organic diaphragm is poor, resulting in a decrease in the adhesion between the ceramic particles and the organic diaphragm, resulting in The material falls off and the powder falls off, which reduces the high temperature resistance of the separator and affects the performance of the battery

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