Separator for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery using the same

Abstract

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 1.5 μm or more and less than 11 μm, and the average distance between the folded-chain crystals adjacent to each other is 0.3 μm or more and less than 0.9 μm. 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.

Dependencies are inferred from the claim text.