Abstract: The present invention provides a sealed battery having a large capacity by using a thin safety valve device so as to increase a volume of a cell element. The sealed battery has a high safety owing to the thin safety valve device having an elastic valve element comprising an ethylene-propylene elastomer and thermoplastic resin particles dispersed in the ethylene-propylene elastomer. The elastic valve element is produced by mixing thermoplastic resin particles with an ethylene-propylene elastomer material, molding the mixture into a predetermined shape and, at the same time, crosslinking the ethylene-propylene elastomer material.

Abstract: A hydrogen storage alloy electrode comprising, an electrically conductive support made of a punched or perforated metal sheet, a mixture supported on said conductive support and a water-repellent agent for giving a water-repellent property on the surface of the electrode, said mixture including; a hydrogen storage alloy powder, a styrene-butadiene copolymer having a styrene to butadiene weight ratio in a range of 100:30 to 100:100 as a binder, a polymeric material for giving a hydrophilic property inside the electrode, and carbon black for giving a hydrophobic property inside the electrode.