Abstract: A lithium battery and process of making same involves employing alternate layers of a lithium anode and an aluminum foil or NiAl expanded metal supported cathode assembly with a gel electrolyte contacting the alternate layers. The electrolyte includes a quantity of N-methyl-2-pyrrollidone and lithium contained within a polyimide matrix and the entire assembly is contained within a sealed polyimide casing. Separate electrical contacts are provided for each of the lithium anode assembly and the aluminum foil or NiAl supported cathode assembly. An out-gassing vent tube extends from the sealed polyimide casing and is sealed a predetermined time after battery construction.