The production process of lithium iron battery separator is mainly divided into dry drawing method and wet drawing method. Lithium-ion battery separators must have many characteristics and put forward special requirements for their production process. The production process includes raw material formula and rapid formula adjustment, micropore preparation process, and complete equipment independent design process.

　　The unidirectional dry drawing process is to produce highly oriented polypropylene or polyethylene film with low crystallinity by producing hard elastic fibers. The film is stretched at low temperature to form micro-defects, and then pulled open at high temperature to form micro-pores. At present, more than one-third of my country's production capacity adopts the dry double-drawing process, and products occupy a large proportion in the low-end market.

　　It is produced by wet method, also called phase separation or thermally induced phase separation method, wet method liquid hydrocarbon or small molecule substance is mixed with polyolefin resin, after melting, it is heated to form a homogeneous mixture, then the phase separation is cooled, the diaphragm is inhibited, and then heated to The melting point temperature near the diaphragm and the orientation of the biaxially stretched molecular chains, the holding time, and the residual volatile substances in the eluting solvent can be prepared by microporous membrane materials.

　　The wet method can not only prepare interpenetrating microporous membrane materials, but also can prepare lithium ion battery separators with higher longitudinal and lateral strength. At present, the wet process is mainly used to produce single-layer lithium ion battery separators.

　　Feeding: Pre-treat PE, PP and other raw materials and additives according to the formula and transport them to the extrusion system.

　　Fluidization: The pretreated raw materials are melted and plasticized in the extrusion system and then extruded from the die. The melt fluidizes to form a base film with a specific crystal structure.

　　Heat treatment: heat treatment of the base film to obtain a hard elastic film.

　　Stretching: stretch the hard elastic film through cold and heat to form a nanoporous film.

　　Slitting: According to customer requirements, cut nanoporous membranes into finished membranes.