Battery separator and method of making same

摘要

A battery separator comprises a multi-layered film, individual layers of film having been bonded together by heat and pressure, having a peel strength of greater than or equal to 40 grams per inch (1.6 g/mm) and a thickness of ≦25 microns. A method for making a battery separator comprises the steps of: extruding and winding up a first precursor film, extruding and winding up a second precursor film, unwinding the first and second precursor films, stacking up the first and second precursor films to form a single stacked precursor, laminating the single stacked precursor film, winding up the laminated single stacked precursor film, stacking up a plurality of laminated single stacked precursor films, and making microporous the stacked plurality of laminated single stacked precursor films.

主权项

1. A method of making a battery separator for a lithium battery, the battery separator being a multi-layered microporous film, individual layers of said film having been bonded together by heat and pressure, having a peel strength of greater than 60 grams per inch (2.4 g/mm) and a thickness of ≦25 microns, comprising the steps of:
extruding and winding up a first precursor film; extruding and winding up a second precursor film; unwinding the first and second precursor film; stacking up the first and second precursor films to form a single, nonporous stacked precursor film; laminating only the single stacked precursor film at speeds greater than 125 ft/min (38.1 m/min) between heated nip rollers having a temperature ranging from 145° C. to 170° C. thereby bonding the stacked first and second precursor films to one another; cooling the laminated, single nonporous stacked precursor film; winding up the laminated, single nonporous stacked precursor film; stacking up a plurality of laminated, single nonporous stacked precursor films; and making microporous said stack of plurality of laminated single stacked precursor films.