SEPARATOR FOR NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY AND NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY USING THE SAME

摘要

Disclosed is a separator for a non-aqueous electrolyte secondary battery, the separator including a biaxially-oriented polyolefin porous film including extended-chain crystals and folded-chain crystals, wherein the extended-chain crystals and the folded-chain crystals form a shish-kebab structure. The average distance between the extended-chain crystals adjacent to each other is 1.5μm or more and less than 11μm, and the average distance between the folded-chain crystals adjacent to each other is 0.3μm or more and less than 0.9μm. A heat resistant porous film may be laminated on the polyolefin porous film. The heat resistant porous film includes a resin having heat resistance or a melting point higher than a melting point of the polyolefin porous film.