The present subject matter relates to a method which includes positioning a bottom and top polymeric separator sheet on a working surface, with a substantially planar battery anode disposed therebetween; applying a pressure and an electrical current to a cutting and welding tool such that top and bottom polymeric separator sheets are welded into a bag and such that the bag is excised from the top and bottom separator sheets, with the battery anode disposed in the bag; stacking the battery anode and at least one cathode into a battery stack; and disposing the battery stack into a battery case having at least one feedthrough, with a first terminal connected to the battery stack through the at least one feedthrough, and with the battery case filled with an electrolyte, wherein the protrusion is defined by laser cutting the cutting and welding tool, machining the cutting and welding tool, or photochemical etching the cutting and welding tool.