Method to fabricate a reliable electrical storage device and the device thereof

An improved method to produce a dry preunit of an electrical storage device for storage of electrical charge in a condition to have the electrode surfaces contacted with a non-aqueous or aqueous electrolyte to operate in a double layer manner, which method comprises:

• (a) obtaining a thin flat metal sheet support wherein the metal is selected from titanium, zirconium, iron, copper, lead, tin, nickel, zinc or combinations thereof said support, having a thickness of between about 0.1 and 10 mil and coated on each flat surface with a thin layer of at least one metal oxide having a porous high surface area independently selected from metal oxides of the group consisting of tin, lead, vanadium, titanium, ruthenium, tantalum, rhodium, osmium, iridium, iron, cobalt, nickel, copper, molybdenum, niobium, chromium, manganese, lanthanum or lanthanum series metals or alloys or combinations thereof, possibly containing a small percentage of additives to enhance electrical conductivity, wherein the thin metal oxide layer has a thickness of between about 0.1 and 100 microns, optionally with the provision that both flat surfaces of the electrically conducting sheet have the perimeter edge surfaces devoid of metal oxide;
• (b) creating an ion permeable space separator which is chemically stable to said aqueous or non-aqueous electrolyte selected from:
• (i) depositing a substantially uniform in height array of electrically insulating microprotrusions which are stable to an aqueous or non-aqueous electrolyte, said microprotrusions having a height of between about 0.1 and 10 mil on the surface of one or both sides of the thin layer of porous metal oxide,
• (ii) placing a thin precut ion permeable electrically insulating separator having a thickness of between about 0.1 and 10 mil on one flat surface of the metal oxide layer;
• (iii) casting an ion permeable or semipermeable separator having a thickness of between about 0.1 and 10 mil on at least one surface of the second electrically conducting material;
• or
• (iv) creating a thin air space as a separator;
• (c) contacting the perimeter edge surface of one or both sides of the thin electrically conducting sheet of step (b) with one or more thin layers of synthetic organic polymer as a gasket material wherein the polymer is selected from the group consisting of polyimides, polyethylenes, polypropylenes, polyolefins, polysulfone, fluorinated polymers partly fluorinated polymers and combinations thereof;
• (d) placing on or within the gasket material and optionally across the thin flat sheet at least one thin cord of a different material in which the has a higher melting temperature (T.sub.m) than the polymeric gasket material, which cord does not melt, flow or adhere to the gasket material under the processing conditions described herein;
• (e) assembling a repeating layered stack of the thin flat articles of sheet coated with metal oxide and separator produced in step (d) optionally having end sheets having only one side coated and/or being made of thicker support material;
• (f) heating the layered stack of step (e) at 0.degree. to 100.degree. C. greater than the T.sub.m causing the gasket material to flow, to adhere to, and to seal the edges of the layered stack creating a solid integral layered stack of sheet and separator optionally enclosing the stack in an integral polymer enclosure;
• (g) cooling to ambient temperature the solid integral stack of step (f) in an inert environment;
• and
• (h) removing the at least one thin cord between each layer creating at least one small opening between the electrode layers.