Abstract: Disclosed herein are novel or improved microporous battery separator membranes, separators, batteries including such separators, methods of making such membranes, separators, and/or batteries, and/or methods of using such membranes, separators and/or batteries. Further disclosed are laminated multilayer polyolefin membranes with exterior layers comprising one or more polyethylenes, which exterior layers are designed to provide an exterior surface that has a low pin removal force. Further disclosed are battery separator membranes having increased electrolyte absorption capacity at the separator/electrode interface region, which may improve cycling. Further disclosed are battery separator membranes having improved adhesion to any number of coatings. Also described are battery separator membranes having a tunable thermal shutdown where the onset temperature of thermal shutdown may be raised or lowered and the rate of thermal shutdown may be changed or increased.

Abstract: The present invention relates in at least selected embodiments to novel or improved microporous battery separators for lithium rechargeable batteries and/or related methods of making and/or using such separators. A particular inventive dry process battery separator or membrane separator exhibits a thickness that is less than about 14 ?m and has increased strength performance as defined by reduced splittiness. The mode of splitting failure has been investigated, and the improvement in splittiness quantified by a novel test method known as the Composite Splittiness Index (CSI).

Abstract: A method for removing a pin from a battery assembly by the step of providing a separator comprising: a microporous membrane having an exterior surface portion of polypropylene, the polypropylene including at least 50 ppm of metallic stearate, preferably calcium stearate Static and being adapted to exhibit a pin removal force ≦7100 g.

Abstract: A method for removing a pin from a battery assembly by the step of providing a separator comprising: a microporous membrane having an exterior surface portion of polypropylene, the polypropylene including at least 50 ppm of metallic stearate, preferably calcium stearate Static and being adapted to exhibit a pin removal force ≦7100 g.