High-tortuosity lithium ion battery film and preparation method thereof

Abstract

The invention discloses a high-tortuosity lithium ion battery film and a preparation method thereof, and the battery film is prepared from the following raw materials in percentage by weight: 67%-74% of a pore-foaming agent, 25%-30% of ultra-high molecular weight polyethylene, 0.1%-0.2% of polycarbonate, 0.1%-2% of polypropylene random copolymer, 0.1%-0.2% of chlorinated polyethylene, 0.1%-0.2% of polymethyl methacrylate, 0.1%-0.2% of a dispersing agent, 0.1%-0.2% of reinforced fiber, 0.1%-0.2% of colloidal silicon dioxide, 0.1%-0.2% of compatilizer and 0.1%-0.2% of cross-linking agent, wherein the dispersing agent is prepared from polyvinylpyrrolidone and methylnaphthalene. When ultra-high molecular weight polyethylene and white oil are selected to be mixed, polycarbonate, polypropylene random copolymer, chlorinated polyethylene, polymethyl methacrylate, polyvinylpyrrolidone, reinforced fibers, colloidal silicon dioxide, a compatilizer and a cross-linking agent are added at the same time to be mixed, and then longitudinal and transverse stretching is carried out, and finally, the lithium battery diaphragm which is obvious in crosslinking, complex in three-dimensional space structure and high in tortuosity pore structure is obtained.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a lithium-ion battery film with high tortuosity and a preparation method thereof. Background technique [0002] Lithium-ion batteries are composed of four parts: positive electrode material, negative electrode material, separator and electrolyte. Among them, the diaphragm is an important part of the lithium battery, which separates the positive and negative electrodes of the battery and prevents the short circuit caused by the contact between the two electrodes. In addition, it also has the function of allowing electrolyte ions to pass freely between the positive and negative electrodes. Function, and when the battery is overheated, the "closed cell function" is used to prevent the conduction of current in the battery. If the tortuosity of the micropores of the diaphragm is too small, the pores of the diaphragm will be close to the ideal parallel net post channel, the ...

AI Technical Summary

Problems solved by technology

If the tortuosity of the micropores of the diaphragm is too small, the pores of the diaphragm will be close to the ideal parallel net column channel, the puncture strength of the diaphragm will be greatly reduced, and the risk of short circuit due to positive and negative contact will be increased. It is difficult to fuse and close, which reduces the safety performance of lithium batteries. Therefore, it is particularly important to invent a high-tortuosity lithium-ion battery film and its preparation method

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