SEPARATOR FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERY AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY INCLUDING THE SAME

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 (mum) to maximum pore diameter (mum) as determined in accordance with ASTM F316-86 is 0.6 or greater; and a nonaqueous electrolyte secondary battery including the separator.