Preparation method of inorganic and organic composite coating diaphragm

Abstract

The invention relates to a preparation method of an inorganic and organic composite coating diaphragm, and belongs to the technical field of lithium ion batteries. The preparation method comprises thefollowing steps: (1) preparing slurry: mixing 20-25 parts by weight of PVDF, 30-35 parts by weight of polyvinyl alcohol solution, 20-25 parts by weight of deionized water and 10-15 parts by weight ofa 1-1.5% CMC aqueous solution, adding 1-5 parts by weight of dispersants, 10-15 parts by weight of 1-1.5% CMC aqueous solution, 20-25 parts by weight of deionized water and 5-15 parts by weight of alumina powders, then, adding 1-3 parts by weight of coagulants and 0.5-1 part by weight of wetting agents, and carrying out stirring to obtain composite slurry; and (2) coating the composite slurry ona PE diaphragm, and carrying out drying in a drying oven at the temperature of 40-80 DEG C to obtain the inorganic and organic composite coating diaphragm. The diaphragm prepared by adopting the preparation method has excellent heat resistance, good mechanical tensile property and higher anti-stripping strength; and the method is simple and low in cost and meets use requirements of the lithium ionbattery.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a method for preparing an inorganic-organic composite coating diaphragm Background technique [0002] Lithium-ion batteries have become a hot spot in power technology research in recent years because of their high specific energy, long cycle life, no memory effect, safety, reliability, and ability to carry rapid redischarge. Lithium-ion batteries play an irreplaceable role in widely used devices such as mobile phones, laptop computers, and now emerging electric and hybrid vehicles. [0003] The main structure of lithium-ion batteries includes positive / negative electrode materials, electrolytes, battery separators, and battery casing packaging materials. The battery separator is an important part of the lithium-ion battery. It plays a role in directly separating the positive and negative electrodes and preventing the battery from short circuiting. In the process of...

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Problems solved by technology

[0005] The surface of the above-mentioned battery separator is coated with a separator slurry. Because the separator slurry uses polyimide as the main body, the heat resistance of the separator can be significantly improved. Because the molecular chains of the aromatic polyamide and the polyimide interpenetrate each other, an interconnected structure is formed. Wearing polymers can significantly improve the mechanical properties of the diaphragm. However, the polyimide material itself has the disadvantages of not being easy to bond and difficult to cure at room temperature, resulting in low peel strength between the slurry coating and the surface of the diaphragm. The coating is easy to peel off the surface of the diaphragm

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