LAMINATE POROUS FILM, SEPARATOR FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERY, AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a laminate porous film to be suitably used as a separator for an on-vehicle battery, the film which has safety in an overcharged state without decreasing air permeability.SOLUTION: The laminate porous film includes a polyolefin resin porous layer 2 having at least a polypropylene resin porous layer 2B having &bgr;-crystal activity, and a conductive layer 4 having a thickness of 0.1 nm to 50 nm layered via an easy adhesion treatment surface 3 applied on a surface of the polypropylene resin porous layer. A difference ratio of the air permeability of the laminate porous film to the air permeability of the polyolefin resin porous layer not laminated with the conductive layer is 1% or more and 30% or less.