Improved microporous membrane separators for lithium ion rechargeable batteries and related methods

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 suchseparators. A particular inventive dry process battery separator or membrane separator exhibits a thickness that is less than about 14 mum and has increased strength performance as defined by reducedsplittiness. 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). 在至少选定的实施方式中，本发明涉及用于锂充电电池的新的或改进的微孔电池隔板和/或涉及制造和/或使用这种隔板的方法。特别的本发明的干法工艺电池隔板或膜隔板表现出小于约14μm的厚度并具有由降低的开裂性定义的强度性能。研究了开裂失效的方式，并用被称为复合开裂指数(CSI)的新测试方法量化了开裂性的改进。