Abstract: A membrane electrode assembly for the fuel cell includes a solid polymer electrolyte membrane, an anode catalyst layer assembled to one surface of the solid polymer electrolyte membrane, and a cathode catalyst layer assembled to another surface of the solid polymer electrolyte membrane. The membrane electrode assembly contains cerium ions. The membrane electrode assembly includes a power-generation region and a non-power-generation region. The power-generation region includes the catalyst layers on both surfaces of the solid polymer electrolyte membrane in a center portion. The non-power-generation region is without the catalyst layer on at least one surface of the solid polymer electrolyte membrane in an outer periphery portion. A cerium ion content per area in the power-generation region is larger than a cerium ion content per area in the non-power-generation region.

Abstract: A membrane electrode assembly for the fuel cell includes a solid polymer electrolyte membrane, an anode catalyst layer assembled to one surface of the solid polymer electrolyte membrane, and a cathode catalyst layer assembled to another surface of the solid polymer electrolyte membrane. The membrane electrode assembly contains cerium ions. The membrane electrode assembly includes a power-generation region and a non-power-generation region. The power-generation region includes the catalyst layers on both surfaces of the solid polymer electrolyte membrane in a center portion. The non-power-generation region is without the catalyst layer on at least one surface of the solid polymer electrolyte membrane in an outer periphery portion. A cerium ion content per area in the power-generation region is larger than a cerium ion content per area in the non-power-generation region.

Abstract: There is provided a method of manufacturing a membrane electrode assembly that has an electrode catalyst layer formed on a surface of an electrolyte membrane. The electrode catalyst layer formed in the membrane electrode assembly is produced by a drying process that dries a catalyst ink which includes catalyst-supported particles having a catalyst metal supported thereon, a solvent and an ionomer, at a predetermined temperature. The catalyst ink includes a plurality of different solvents having different boiling points. The predetermined temperature is set to be lower than the boiling point of the solvent having the lowest boiling point among the plurality of different solvents.

Abstract: There is provided a method of manufacturing an electrode catalyst layer for fuel cell. This manufacturing method comprises: (a) separating an ionomer solution by centrifugation into a supernatant that includes only an ionomer as a low molecular-weight component in the ionomer solution and a sediment including an ionomer as a high molecular-weight component having a higher molecular weight than that of the low molecular-weight component included in the supernatant; (b) using the ionomer included in the sediment as an ionomer for electrode catalyst layer and producing a catalyst ink that includes catalyst-supported particles with a catalyst metal supported thereon, a solvent and the ionomer for electrode catalyst layer; and (c) using the catalyst ink to form an electrode catalyst layer.

Abstract: A catalyst electrode layer is configured to be disposed in contact with an electrolyte membrane of a fuel cell. A content of Fe per unit area of the catalyst electrode layer is equal to or larger than 0 ?g/cm2 and equal to or smaller than 0.14 ?g/cm2, and a water absorption rate of the catalyst electrode layer is equal to or higher than 11% and equal to or lower than 30%.

Abstract: The method of manufacturing a membrane electrode assembly that has an electrode catalyst layer formed on a surface of an electrolyte membrane comprises (a) producing an electrode catalyst layer by drying a catalyst ink that includes catalyst-supported particles having a catalyst metal supported thereon, a solvent and an ionomer; and (b) selecting a produced electrode catalyst layer that contains an amount of sulfate ion equal to or less than a specified reference value, and manufacturing the membrane electrode assembly by using the selected electrode catalyst layer.

Abstract: An object is to prevent an increase in overall thickness of a membrane electrode assembly. There is provided a membrane electrode assembly. The membrane electrode assembly comprises an electrolyte membrane; a catalyst layer that is formed on a surface of the electrolyte membrane and includes a catalyst and an ionomer; and a gas diffusion layer that is formed on a surface of the catalyst layer on an opposite side to the electrolyte membrane. The catalyst layer includes a first layer that is in contact with the electrolyte membrane and a second layer that is in contact with the gas diffusion layer. An amount of the ionomer in a first portion of the first layer that is in contact with the electrolyte membrane is larger than an amount of the ionomer in a second portion of the first layer that is in contact with the second layer. An amount of the ionomer in a third portion of the second layer that is in contact with the gas diffusion layer is larger than the amount of the ionomer in the first portion.

Abstract: A membrane electrode assembly for use in a fuel cell battery includes: an electrolyte membrane; an anode catalyst layer formed on a first surface of the electrolyte membrane; a cathode catalyst layer formed on a second surface of the electrolyte membrane; an anode gas diffusion layer stacked on the anode catalyst layer; and a cathode gas diffusion layer stacked on the cathode catalyst layer. The anode catalyst layer, the cathode catalyst layer, the anode gas diffusion layer, and the cathode gas diffusion layer have the same thermal insulation performance per thickness. The membrane electrode assembly satisfies all relations of T1+T3<T2+T4, T1<T2, and T3>T4 where thicknesses of the anode catalyst layer, the cathode catalyst layer, the anode gas diffusion layer, and the cathode gas diffusion layer in a stacking direction are defined as T1, T2, T3, and T4, respectively.

Abstract: An object is to prevent an increase in overall thickness of a membrane electrode assembly. There is provided a membrane electrode assembly. The membrane electrode assembly comprises an electrolyte membrane; a catalyst layer that is formed on a surface of the electrolyte membrane and includes a catalyst and an ionomer; and a gas diffusion layer that is formed on a surface of the catalyst layer on an opposite side to the electrolyte membrane. The catalyst layer includes a first layer that is in contact with the electrolyte membrane and a second layer that is in contact with the gas diffusion layer. An amount of the ionomer in a first portion of the first layer that is in contact with the electrolyte membrane is larger than an amount of the ionomer in a second portion of the first layer that is in contact with the second layer. An amount of the ionomer in a third portion of the second layer that is in contact with the gas diffusion layer is larger than the amount of the ionomer in the first portion.

Abstract: The method of manufacturing a membrane electrode assembly that has an electrode catalyst layer formed on a surface of an electrolyte membrane comprises (a) producing an electrode catalyst layer by drying a catalyst ink that includes catalyst-supported particles having a catalyst metal supported thereon, a solvent and an ionomer; and (b) selecting a produced electrode catalyst layer that contains an amount of sulfate ion equal to or less than a specified reference value, and manufacturing the membrane electrode assembly by using the selected electrode catalyst layer.

Abstract: There is provided a method of manufacturing a membrane electrode assembly that has an electrode catalyst layer formed on a surface of an electrolyte membrane. The electrode catalyst layer formed in the membrane electrode assembly is produced by a drying process that dries a catalyst ink which includes catalyst-supported particles having a catalyst metal supported thereon, a solvent and an ionomer, at a predetermined temperature. The catalyst ink includes a plurality of different solvents having different boiling points. The predetermined temperature is set to be lower than the boiling point of the solvent having the lowest boiling point among the plurality of different solvents.

Abstract: A catalyst electrode layer is configured to be disposed in contact with an electrolyte membrane of a fuel cell. A content of Fe per unit area of the catalyst electrode layer is equal to or larger than 0 ?g/cm2 and equal to or smaller than 0.14 ?g/cm2, and a water absorption rate of the catalyst electrode layer is equal to or higher than 11% and equal to or lower than 30%.

Abstract: A membrane electrode assembly for use in a fuel cell battery includes: an electrolyte membrane; an anode catalyst layer formed on a first surface of the electrolyte membrane; a cathode catalyst layer formed on a second surface of the electrolyte membrane; an anode gas diffusion layer stacked on the anode catalyst layer; and a cathode gas diffusion layer stacked on the cathode catalyst layer. The anode catalyst layer, the cathode catalyst layer, the anode gas diffusion layer, and the cathode gas diffusion layer have the same thermal insulation performance per thickness. The membrane electrode assembly satisfies all relations of T1+T3<T2+T4, T1<T2, and T3>T4 where thicknesses of the anode catalyst layer, the cathode catalyst layer, the anode gas diffusion layer, and the cathode gas diffusion layer in a stacking direction are defined as T1, T2, T3, and T4, respectively.

Abstract: There is provided a method of manufacturing an electrode catalyst layer for fuel cell. This manufacturing method comprises: (a) separating an ionomer solution by centrifugation into a supernatant that includes only an ionomer as a low molecular-weight component in the ionomer solution and a sediment including an ionomer as a high molecular-weight component having a higher molecular weight than that of the low molecular-weight component included in the supernatant; (b) using the ionomer included in the sediment as an ionomer for electrode catalyst layer and producing a catalyst ink that includes catalyst-supported particles with a catalyst metal supported thereon, a solvent and the ionomer for electrode catalyst layer; and (c) using the catalyst ink to form an electrode catalyst layer.

Abstract: In a fuel cell having a separator in which main cooling water channels are formed, a separator for another unit cell stacked on the cooling water channel formation surface side of the separator, and a second sealing member interposed between the separators and to seal a cooling medium flowing in the main cooling water channels, an outer peripheral rib for regulating the flow of cooling water to the second sealing member side is provided inside relative to the second sealing member in the separator surface direction in order to improve the efficiency of cooling with the cooling medium.

Abstract: A fuel cell includes a separator and a power generating body. The separator and power generating body are laminated each other. The power generating body is equipped at least with an electrolyte membrane. The fuel cell comprises: a sealing part that seals reaction gas supplied for electrochemical reactions at the fuel cell between the power generating body and the separator at an outer circumference part of the fuel cell, wherein a convex part and a recess are fit together in the sealing part. The convex part is formed projecting in the lamination direction on one of the power generating body and the separator, and the recess is formed recessed in the lamination direction on the other of the power generating body and the separator. At least one of the convex part and the recess is formed with a polymer material that expands with moisture absorption.

Abstract: A fuel cell includes a separator and a power generating body. The separator and power generating body are laminated each other. The power generating body is equipped at least with an electrolyte membrane. The fuel cell comprises: a sealing part that seals reaction gas supplied for electrochemical reactions at the fuel cell between the power generating body and the separator at an outer circumference part of the fuel cell, wherein a convex part and a recess are fit together in the sealing part. The convex part is formed projecting in the lamination direction on one of the power generating body and the separator, and the recess is formed recessed in the lamination direction on the other of the power generating body and the separator. At least one of the convex part and the recess is formed with a polymer material that expands with moisture absorption.

Abstract: A fuel cell system includes a fuel cell, anode gas pressure adjusting means that adjusts the pressure of an anode gas supplied to the fuel cell, and cathode gas pressure adjusting means that adjusts the pressure of a cathode gas supplied to the fuel cell. The system further includes pressure control means that sets the pressure of the anode gas that is supplied when starting the fuel cell higher than the pressure of the anode gas that is supplied during power generation in the fuel cell, and controls the anode gas pressure adjusting means and the cathode gas pressure adjusting means so that a cathode gas pressure increase is started in accordance with the start of an anode gas pressure increase when the pressure of the anode gas is increased to the set pressure.

Abstract: A fuel cell including separators opposing each other and squeezing a power generating reaction portion. Each of the separators includes a gas passage, a gas passage dividing rib, and a protrusion formed in the gas passage. In a first separator, which is an at least one separator of the separators opposing each other via the power generating reaction portion, at a region of the first separator opposing a gas passage dividing rib of a second separator, which is a separator opposing the first separator, a squeezing rib is formed and replaces the protrusion. The squeezing rib and the gas passage dividing rib of the second separator squeezes the power generating reaction portion. At the region of the first separator, a contact area of the squeezing rib with the power generating reaction portion is adapted to be larger than a contact area of the protrusion of the first separator with the power generating reaction portion in a case where the protrusion were formed without forming the squeezing rib.

Abstract: A fuel cell system includes a fuel cell, anode gas pressure adjusting means that adjusts the pressure of an anode gas supplied to the fuel cell, and cathode gas pressure adjusting means that adjusts the pressure of a cathode gas supplied to the fuel cell. The system further includes pressure control means that sets the pressure of the anode gas that is supplied when starting the fuel cell higher than the pressure of the anode gas that is supplied during power generation in the fuel cell, and controls the anode gas pressure adjusting means and the cathode gas pressure adjusting means so that a cathode gas pressure increase is started in accordance with the start of an anode gas pressure increase when the pressure of the anode gas is increased to the set pressure.