Abstract: Porous electrodes are provided for lead-acid storage batteries without supporting plates or grids. The electrodes are porous, self-supporting, structurally integral and electrically continuous. Lead-acid batteries incorporating such electrodes exhibit improved performance characteristics as compared to conventional lead-acid batteries. The electrodes are made by forming a molten mixture of a metal (e.g. lead) and a pore forming component (e.g. cadmium), cooling and forming the molten mixture into a solid electrode with the pore forming component distributed therethrough, removing the pore forming component from the solid electrode to leave a network of voids defining the pores, and oxidizing the metallic walls within the pores to form a coating of electrochemically active material (e.g., lead dioxide) on the walls within the pores.

Abstract: A complex electrochemical heat-generating element characterized by a two-surfaced anode layer, two separator layers of porous, absorbent material, one on either surface of the anode layer, two cathode layers, one in contact with each of the separator layers, and electrically conductive connectors extending through the cathode layers, separator layers and anode layer to conduct an electric heating current between the anode and cathode layers. Preferred embodiments relate to specific arrangements of connectors.

Abstract: A self-contained warming pad characterized by a heating element, an adjacent dose of activating liquid within a frangible container, and a substantially liquid-impervious cover enclosing the element and frangible container and having at least one tortuous air passage therethrough. Features include a cover having thermal insulating qualities, and a frangible container made of a meltable substance having a melting point chosen to control the upper temperatures of the pad. Other features relate to a cover configuration which provides an annular breathing passage, and a porous resilient mass within the pad which provides a substantial breathing capacity. The heating element is preferably an electrochemical element, and most preferably a complex electrochemical element having two cathode layers and one anode layer in a sandwich-like structure.

Abstract: An improvement in the separator layer of an electrochemical heating element having two electrode layers, a separator layer of porous, absorbent material therebetween, and electrically conductive connector means extending through the electrode and separator layers. The improved device includes structural spacing means interposed between one of the electrode layers and at least a portion of the other electrode layer to limit compression of the separator layer material. In one embodiment, discrete mechanical spacers are placed immediately adjacent to the connector means. In another embodiment, a recessed surface portion is formed in one of the electrode layers and the adjacent separator layer has a mating portion on one side which is received into the recessed surface portion.BACKGROUND OF THE INVENTIONThis invention relates to electrochemical heat-generating elements, and, in particular, to improvements in uniformity and performance reproducibility in such elements.The prior art as taught by Kober in U.S. Pat.