MULTI-LAYERED COMPOSITE FUNCTIONAL SEPARATOR FOR LITHIUM-ION BATTERY

A multi-layer composite functional separator for lithium ion battery includes four layers. Layer A is a base separator. Layer B is a porous structural layer composed of insulating inorganic compounds or high temperature resistant polymers. Layer C is a porous layer composed of polymer microspheres with temperature-induced expansion characteristics. Layer D is a thermoplastic resin with a melting point of 80-110° C. and a crystallinity of