Shutdown, trilayer battery separator and process of manufacture

摘要

The present invention is directed to a shutdown, trilayer battery separator comprising a first and third microporous polypropylene membrane sandwiching a microporous polyethylene membrane. The separator has a first and a third microporous membranes sandwiching a second microporous membrane. The first and the third membranes have a greater puncture strength than the second membrane. The second membrane has a lower melting temperature than either the first or the third membranes.