Abstract: A fuel cell is formed by laminating a plurality of cells. Each cell includes a membrane electrode assembly and two separators, which hold the membrane electrode assembly in between. Each separator includes a base member made of a metal material. A first layer is provided on the surface of the base member. The first layer includes a resin film and conductive particles that have greater hardness than the oxide film of the base member. Between the separators that are adjacent to each other, the first layers are in contact with each other.

Abstract: A fuel cell is formed by laminating a plurality of cells. Each cell includes a membrane electrode assembly and two separators, which hold the membrane electrode assembly in between. Each separator includes a base member made of a metal material. A first layer is provided on the surface of the base member. The first layer includes a resin film and conductive particles that have greater hardness than the oxide film of the base member. Between the separators that are adjacent to each other, the first layers are in contact with each other.

Abstract: A fuel cell stack includes a plurality of cells each including an MEA 10 sandwiched by separators 20. A hydrogen gas supply pipe 31 and an air supply pipe 32 for externally supplying gas, and a hydrogen gas discharge pipe 35 and an air discharge pipe 36 for discharging unreacted gas are connected to the stack. Gas-supply-side valves 33 and 34 are installed in the pipes 31 and 32, respectively. Gas-discharge-side valves 37 and 38 are installed in the pipes 35 and 36, respectively. The valves 33 and 37 close an anode-electrode-layer-side space including an anode electrode layer. The valves 34 and 38 close a cathode-electrode-layer-side space including a cathode electrode layer. This structure prevents introduction of new air, thereby suppressing an increase in the concentration of nitrogen gas in the anode-electrode-layer-side space.

Abstract: An MEA includes an electrolyte membrane permeable to hydroxide ions. A catalyst layer formed of a hydrogen storage alloy is provided on one surface of the membrane facing the anode electrode layer. Another catalyst layer formed of platinum-on carbon is provided on the opposite surface of the membrane facing the cathode electrode layer. The catalyst layer on the anode-electrode-layer side dissociates hydrogen gas into atomic hydrogen, diffuses the atomic hydrogen by way of solid phase diffusion, and absorbs/desorbs atomic hydrogen. The catalyst layer on the cathode-electrode-layer side forms hydroxide ions from air, humidifying water, and electrons. The membrane allows movement of the hydroxide ions to the catalyst layer on the anode-electrode-layer side. This leads to formation of water on the anode-electrode-layer side, whereby occurrence of dry-up can be prevented. Even when flooding arises from formed water, atomic hydrogen can smoothly move through solid-phase diffusion.