摘要:
It is intended to enhance the battery performance, such as load characteristics, of nonaqueous electrolyte secondary battery wherein use is made of a separator constituted of a thermoplastic resin porous membrane containing a filler. In particular, a separator for nonaqueous electrolyte secondary battery, comprised of a porous membrane having a filler contained in a thermoplastic resin, wherein the ratio of average pore diameter (μm) to maximum pore diameter (μm) as determined in accordance with ASTM F316-86 is 0.6 or greater; and a nonaqueous electrolyte secondary battery including the separator.