Abstract: A polymer electrolyte fuel cell system is disclosed, comprising a fuel cell having a predetermined power generation portion configured to operate at a predetermined temperature to generate an electric power using a fuel gas and an oxidizing gas supplied to said fuel cell, and a humidifier configured to humidify the fuel gas and the oxidizing gas, wherein the humidifier is configured to humidify the fuel gas and the oxidizing gas to allow the fuel gas and the oxidizing gas to have dew points higher than the predetermined temperature, the humidified fuel gas and oxidizing gas having the dew points higher than the operating temperature being supplied to the fuel cell.

Abstract: A polymer electrolyte fuel cell has an MEA-gasket assembly including an MEA having a polymer electrolyte membrane, a pair of catalyst layers, and a pair of gas diffusion electrodes, and a pair of gaskets provided on peripheral portions of surfaces on both sides of the MEA with gaps between the respectively adjacent gaskets and gas diffusion electrodes. A pair of electrically conductive separators is disposed to sandwich the MEA-gasket assembly with groove-shaped cell reaction gas passages on inner surfaces of the separators, each of the cell reaction gas passages running sequentially across a first portion of a respective gasket of the pair of gaskets, a first portion of a respective gap of the gaps, a respective gas diffusion electrode of the pair of gas diffusion electrodes, a second portion of the respective gap, and a second portion of the respective gasket. Each of the gaps is at least partially closed by a closure.

Abstract: A configuration of an electrolyte membrane for a fuel cell is provided, which can be sealed reliably and easily between the separators. The sealing configuration is between the separators and between a peripheral portion of the electrolyte membrane and the respective separators. The sealing configuration includes a frame having an elastic modulus of greater than about 2,000 MPa and less than about 2,000,000 MPa and an elastic body having an elastic modulus of greater than 0 MPa and less than about 200 MPa. In one embodiment, the separators or portions thereof may themselves constitute the at least one elastic body. In another embodiment, the electrolyte membrane may be held by two frames lying on opposite sides of the electrolyte membrane, with the at least one elastic body arranged between the first and second frames sandwiching the membrane and also between the frames and the respective separators.

Abstract: A separator plate for a polymer electrolyte fuel cell having excellent conductivity and moldability is provided. The separator plate is injection molded, using different compounds for molding the portion that requires conductivity and the portion that does not require conductivity. The separator plate comprises: an electronic conductor portion containing conductive carbon; and an insulating portion surrounding the electronic conductor portion. The electronic conductor portion has a first flow channel of a gas or cooling water on one side and has a second flow channel of a gas or cooling water on the other side.

Abstract: A fuel cell having high operation performance and reliability is provided by optimizing the shape and properties of a gas diffusion layer and the dimensions of a gas flow channel. The fuel cell evenly supplies a reaction gas to the catalyst of a catalyst layer and promptly discharges excessive water generated therein. The gas diffusion layer of the MEA comprises a first section having a surface A coming in direct contact with a separator plate and a second section having a surface B facing the gas flow channel of the separator plate. The porosity of the first section is lower than the porosity of the second section, and the second section protrudes into the gas flow channel, which has sufficient width and depth for the protrusion of the gas diffusion layer, and the width of a rib formed by the gas flow channel is sufficiently narrow.

Abstract: A polymer electrolyte fuel cell has an MEA-gasket assembly including an MEA having a polymer electrolyte membrane, a pair of catalyst layers, and a pair of gas diffusion electrodes, and a pair of gaskets provided on peripheral portions of surfaces on both sides of the MEA with gaps between the respectively adjacent gaskets and gas diffusion electrodes. A pair of electrically conductive separators is disposed to sandwich the MEA-gasket assembly with groove-shaped cell reaction gas passages on inner surfaces of the separators, each of the cell reaction gas passages running sequentially across a first portion of a respective gasket of the pair of gaskets, a first portion of a respective gap of the gaps, a respective gas diffusion electrode of the pair of gas diffusion electrodes, a second portion of the respective gap, and a second portion of the respective gasket. Each of the gaps is at least partially closed by a closure.

Abstract: A polymer electrolyte fuel cell system is disclosed, comprising a fuel cell having a predetermined power generation portion configured to operate at a predetermined temperature to generate an electric power using a fuel gas and an oxidizing gas supplied to said fuel cell, and a humidifier configured to humidify the fuel gas and the oxidizing gas, wherein the humidifier is configured to humidify the fuel gas and the oxidizing gas to allow the fuel gas and the oxidizing gas to have dew points higher than the predetermined temperature, the humidified fuel gas and oxidizing gas having the dew points higher than the operating temperature being supplied to the fuel cell.

Abstract: A configuration of an electrolyte membrane for a fuel cell is provided, which can be sealed reliably and easily between the separators. The sealing configuration is between the separators and between a peripheral portion of the electrolyte membrane and the respective separators. The sealing configuration includes a frame having an elastic modulus of greater than about 2,000 MPa and less than about 2,000,000 MPa and an elastic body having an elastic modulus of greater than 0 MPa and less than about 200 MPa. In one embodiment, the separators or portions thereof may themselves constitute the at least one elastic body. In another embodiment, the electrolyte membrane may be held by two frames lying on opposite sides of the electrolyte membrane, with the at least one elastic body arranged between the first and second frames sandwiching the membrane and also between the frames and the respective separators.

Abstract: A polymer electrolyte fuel cell stack includes cells having separators that can be supplied fuel or oxidant either in series or in parallel is disclosed. At high power loads the cells are operated in parallel, and at low power load the cells are operated in series. Advantageously, operating the cells in series at low power loading allows high gas flows thereby minimizing water condensation and improving the stability and performance of the cell stack during low load operation. Individual cells include a polymer electrolyte membrane sandwiched by a pair of electrodes, which in turn are sandwiched by a pair of electrically conductive separators. The separators have gas channels on their surfaces to supply oxidant gas and fuel gas to the cathode and anode, respectively, that can be manipulated to operate in parallel or series.

Abstract: A separator plate for a polymer electrolyte fuel cell having excellent conductivity and moldability is provided. The separator plate is injection molded, using different compounds for molding the portion that requires conductivity and the portion that does not require conductivity. The separator plate comprises: an electronic conductor portion containing conductive carbon; and an insulating portion surrounding the electronic conductor portion. The electronic conductor portion has a first flow channel of a gas or cooling water on one side and has a second flow channel of a gas or cooling water on the other side.

Abstract: A fuel cell having high operation performance and reliability is provided by optimizing the shape and properties of a gas diffusion layer and the dimensions of a gas flow channel. The fuel cell is capable of evenly supplying a reaction gas to the catalyst of a catalyst layer and promptly discharging excessive water generated therein. The gas diffusion layer of the MEA of this fuel cell comprises a first section having a surface A that comes in direct contact with a separator plate and a second section having a surface B that faces the gas flow channel of the separator plate. The porosity of the first section is lower than the porosity of the second section, and the second section protrudes into the gas flow channel. The gas flow channel has sufficient width and depth for the protrusion of the gas diffusion layer, and the width of a rib formed by the gas flow channel is sufficiently narrow.