Multilayer porous membrane production method, lithium ion battery separator and lithium ion battery

摘要

PPROBLEM TO BE SOLVED: To provide a manufacturing method capable of efficiently manufacturing a multilayer porous membrane having high uniformity; a separator for an electrochemical element made of the multilayer porous membrane; and the electrochemical device having the multilayer porous membrane as the separator. PSOLUTION: A method manufacturing the multilayer porous membrane having a resin porous membrane containing thermoplastic resin as the main component and a heat-resistant porous layer containing heat-resistant fine particles as the main component has a process surface-treating the resin porous membrane and a process forming the heat-resistant porous layer by applying a heat-resistant porous layer forming composition to the surface of the surface-treated resin porous membrane, wherein the relation between the surface tension (A) of the heat-resistant porous layer forming composition and the critical surface tension (B) at the room temperature of the resin porous membrane before surface treatment is set to (A)-(B)10 mN/m, and the relation between the surface tension (A) and the critical surface tension (B') at the room temperature of the resin porous membrane after surface treatment is set to (A)-(B')0 mN/m. PCOPYRIGHT: (C)2009,JPO&INPIT