MICROLAYER MEMBRANES, IMPROVED BATTERY SEPARATORS, AND METHODS OF MANUFACTURE AND USE

In accordance with at least selected embodiments, a battery separator or separator membrane comprises one or more co-extruded multi-microlayer membranes optionally laminated or adhered to another polymer membrane. The separators described herein may provide improved strength, for example, improved puncture strength, particularly at a certain thickness, and may exhibit improved shutdown and/or a reduced propensity to split.