The main function is to isolate the positive and negative poles to prevent self-discharging of the battery and short-circuit at both poles. 

The main materials are porous polymer membranes, including dry separator, ceramic coating separator and PET non-woven separator.

 Because the separator's safety, permeability, porosity, and film thickness will affect ionic conductivity and mechanical strength, different products must be manufactured using different design methods, such as single-layer, double-layer and three-layer film. 

For different processes and raw materials, we can develop different applications of Li-ion battery separator, and have stable mass production experience to improve product performance and quality.