Patent ID: 6842330

Claim:
A long life double layer capacitor comprising: a case; a first terminal; an electrically insulating hermetic seal interposed between the first terminal and the case; a first current collector foil electrically coupled to an interior portion of the first terminal; a first electrode, wherein the first electrode comprises carbon, the first electrode being juxtaposed against one side of the first current collector foil; a porous separator juxtaposed against another side of the first electrode; a second electrode, wherein the second electrode comprises carbon, one side of the second electrode being juxtaposed against the porous separator, wherein the porous separator is interposed between the first electrode and the second electrode; a second current collector foil, the second current collector foil being juxtaposed against another side of the second electrode; a second terminal electrically coupled to the second current collector foil; and an electrolyte solution saturating the first electrode and the second electrode, wherein the electrolyte solution is substantially contained by the case and the electrically insulating hermetic seal, and wherein influx of impurities into the electrolyte solution is substantially inhibited by the case and the electrically insulating hermetic seal.