In accordance with at least selected aspects, objects or embodiments, optimized, novel or improved membranes, battery separators, batteries, and/or systems and/or related methods of manufacture, use and/or optimization are provided. In accordance with at least selected embodiments, the present invention is related to novel or improved battery separators that prevent dendrite growth, prevent internal shorts due to dendrite growth, or both, batteries incorporating such separators, systems incorporating such batteries, and/or related methods of manufacture, use and/or optimization thereof. In accordance with at least certain embodiments, the present invention is related to novel or improved ultra thin or super thin membranes or battery separators, and/or lithium primary batteries, cells or packs incorporating such separators, and/or systems incorporating such batteries, cells or packs. In accordance with at least particular certain embodiments, the present invention is related to shutdown membranes or battery separators, and/or lithium primary batteries, cells or packs incorporating such separators, and/or systems incorporating such batteries, cells or packs.