Lithium ion battery diaphragm, lithium ion battery and preparation method of lithium ion battery diaphragm

Abstract

The invention provides a lithium ion battery diaphragm, a lithium ion battery and a preparation method of the lithium ion battery diaphragm. The lithium ion battery diaphragm comprises a base membrane and a ceramic coating covering the surface of the base membrane, and the ceramic coating comprises the following raw materials in parts by weight: 1 part of aluminum oxide; 0.01 to 0.02 part of a thickening agent; 0.008 to 0.012 part of a solution type water-based adhesive; 0.03 to 0.05 part of an emulsion type water-based adhesive; 0.001 to 0.01 part of a dispersing agent; and 0.0001 to 0.0005 part of a wetting agent. The lithium ion battery diaphragm disclosed by the invention has relatively good thermal shrinkage performance and puncture strength, and the safety of the battery is improved.

Description

technical field [0001] The invention belongs to the field of lithium battery separators, and relates to a lithium ion battery separator, a lithium ion battery and a preparation method of the lithium ion battery separator, in particular to a safer lithium ion battery separator and a preparation method thereof. Background technique [0002] Lithium-ion battery separators are mainly porous polyolefins. At present, polyethylene or polypropylene is widely used, which can maintain thermal stability (-20°C to 60°C) during battery use. At the same time, the separator plays a role in the positive and negative electrodes of the battery. Electronic insulation also provides channels for the free migration of ions in the electrolyte. [0003] With the advancement of science and technology, people have higher and higher requirements for high-power and portable electronic equipment, especially for high-current, high-rate discharge, high heat resistance, and good ability to absorb and maint...

AI Technical Summary

Problems solved by technology

[0004] At present, the main problems of the ceramic diaphragm are: 1. During the use of the battery, due to the high heat release temperature, the diaphragm will close the pores by itself, but as the temperature rises further, the thermal shrinkage of the diaphragm will cause the positive and negative poles of the battery to 2. During the repeated charging and discharging process, the dendrites generated on the surface of the electrode will cause the diaphragm to be damaged and cause a short circuit; at the same time, due to the uneven surface of the electrode and the technological level in the assembly process, the diaphragm will be stabbed 3. During the battery manufacturing process, the peeling strength between the coating and the base film is too small, which will firstly cause the powder to fall from the separator during the winding process of the battery; At the end of the battery cycle, the internal impedance of the battery will increase and the cycle performance of the battery will be reduced.

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