Abstract: A method for production of porous electrodes and separators in polymer type electrochemical cells and batteries wherein electrodes and separator elements are mixed with polymeric filler materials such as dibutyl phthalate (DBP). The polymeric filler material is then removed to provide the requisite porosity for the electrodes and separator. The polymeric filler material, normally removed by use of volatile solvents, is instead removed by extraction with supercritical fluids, such as CO.sub.2, which do not result in any hazardous residue or gases.

Abstract: A low pressure vented battery structure comprised of lithium ion polymer cells contained within a flexible container. The flexible container is punctured to provide a venting aperture. The venting aperture is externally sealingly covered with a vent structure comprising a first chemically inert plastic film layer having a central aperture which is adhered to the flexible container around the periphery of the central aperture, with the central aperture being in registration with the venting aperture. A second film chemically inert layer membrane is partially adhered to the first layer, whereby the membrane is stretched and anchored in a position covering the central aperture and the venting aperture, and partially separated from the first layer to provide a venting pathway from the venting aperture to the ambient atmosphere.

Abstract: Internal intercell and terminal cell electrical connector elements in an electrochemical battery are protected from corrosion and build-up of high internal resistance by coating the electrical connector elements with a layer of a protective preferably non-conductive viscous material such as silicone, prior to pressure contacting or welding of the electrical connector elements. The silicone is removed only at the point of contact between the connector elements while retaining a surrounding protective barrier against the corrosive effects of the cell components and particularly corrosive fluid organic electrolyte materials in high energy density cells.