. . "The composite polymer electrolyte layer 12 may include an electrically non-conductive ribbon net 12A of expanded or perforated plastic film material, which is inert to the battery components and is preferably of polypropylene, but other materials such as polyethylene, polyester, ethylenetetrafluoroethylene, polyetetrafluoroethylene, polyvinylchloride, and their variations are also suitable as desc" . .