Abstract: A separator includes a base including projections. The base is made of a metal plate. The separator includes a conductive layer arranged on a top surface of each of the projections of the base. The conductive layer includes conductive carbon materials, conductive particles, and a thermosetting resin. The conductive carbon materials and the conductive particles are dispersed in the resin and are in contact with each other over an entirety of the conductive layer in a thickness direction of the conductive layer.

Abstract: A separator includes a base material made of metal plate and a first layer made of corrosion-resistant material and arranged on the entirety of one surface of the base material. The base material includes extending projections and extending recesses. The projections and the recesses are alternately arranged. The separator includes a second layer including a conductive particle and a binder that is made of plastic material, the second layer being arranged only on a part of a surface of the first layer corresponding to a top surface of the projections of the base material. The conductive particle is contained only in the second layer.

Abstract: A separator includes a base material made of metal plate and a first layer made of corrosion-resistant material and arranged on the entirety of one surface of the base material. The base material includes extending projections and extending recesses. The projections and the recesses are alternately arranged. The separator includes a second layer including a conductive particle and a binder that is made of plastic material, the second layer being arranged only on a part of a surface of the first layer corresponding to a top surface of the projections of the base material. The conductive particle is contained only in the second layer.

Abstract: A separator assembly for a fuel cell includes a first separator, a second separator, and a joined portion. In the joined portion, the first separator and the second separator are joined to each other through laser welding. The first separator includes a first surface that is intended to be opposed to the membrane electrode assembly. The first surface of the first separator includes an exposed portion where the base of the first separator is exposed. The second separator includes a second surface that is intended to be opposed to the membrane electrode assembly. A film including conductive particles is arranged on the entire second surface of the second separator. The joined portion is formed by irradiating the exposed portion of the first separator with laser.

Abstract: A fuel cell stack includes a plurality of power generation cells stacked and connected in series and coolant passages configured to circulate coolant. The power generation cells each include a membrane electrode assembly and two separators sandwiching the membrane electrode assembly. The separators are each formed by a metal plate. The coolant passages include through-holes extending through the separators and aligned in a stacking direction of the power generation cells. A method for manufacturing a fuel cell stack includes forming a coating of electrodeposition paint on surfaces of ones of the separators having a high electric potential in the fuel cell stack by operating the fuel cell stack and using the coolant that contains electrodeposition paint particles.

Abstract: A separator assembly for a fuel cell includes a first separator, a second separator, and a joined portion. In the joined portion, the first separator and the second separator are joined to each other through laser welding. The first separator includes a first surface that is intended to be opposed to the membrane electrode assembly. The first surface of the first separator includes an exposed portion where the base of the first separator is exposed. The second separator includes a second surface that is intended to be opposed to the membrane electrode assembly. A film including conductive particles is arranged on the entire second surface of the second separator. The joined portion is formed by irradiating the exposed portion of the first separator with laser.

Abstract: A fuel cell stack includes a plurality of power generation cells stacked and connected in series and coolant passages configured to circulate coolant. The power generation cells each include a membrane electrode assembly and two separators sandwiching the membrane electrode assembly. The separators are each formed by a metal plate. The coolant passages include through-holes extending through the separators and aligned in a stacking direction of the power generation cells. A method for manufacturing a fuel cell stack includes forming a coating of electrodeposition paint on surfaces of ones of the separators having a high electric potential in the fuel cell stack by operating the fuel cell stack and using the coolant that contains electrodeposition paint particles.

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.