Abstract: A polymer electrolyte fuel cell is provided comprising: a hydrogen ion conductive polymer electrolyte membrane; an anode and a cathode sandwiching the hydrogen ion conductive polymer electrolyte membrane; an anode side electroconductive separator having a gas channel for supplying a fuel gas to the anode; a cathode side electroconductive separator having a gas channel for supplying an oxidant gas to the cathode; characterized in that the anode and the cathode comprise a gas diffusion layer and a catalyst layer formed on the gas diffusion layer at the side in contact with the hydrogen ion conductive polymer electrolyte membrane, the catalyst layer has catalyst particles and a hydrogen ion conductive polymer electrolyte, and at least either of hydrogen ion conductivity and gas permeability of at least either of the anode and the cathode varies in a thickness direction of the anode or the cathode.

Abstract: To provide a gas diffusion layer excellent in micro short-circuit resistance and anti-flooding characteristics by optimizing the surface shape of a gas diffusion layer. In a gas diffusion layer for a gas diffusion electrode including at least a catalyst layer containing an electrode catalyst and a gas diffusion layer having electron conductivity and gas diffusibility, a second surface of the gas diffusion layer, which is positioned opposite to a first surface thereof to be in contact with the catalyst layer, is made rougher than the first surface. The first surface has a maximum height Ry1 of 10 to 50 determined by JIS B 0601 surface roughness measurement method, and the second surface has a maximum height Ry2 of 100 to 500 determined by JIS B 0601 surface roughness measurement method.

Abstract: The present invention provides a gas diffusion layer for a fuel cell which has proper rigidity, is easy to handle and contributes to the improvement of the productivity of fuel cells. A method for producing a gas diffusion layer for a fuel cell including a first step of: impregnating a conductive porous substrate made of a conductive carbon fiber cloth or conductive carbon fiber felt with a first dispersion containing a first fluorocarbon resin having thermoplasticity; and baking the first conductive porous substrate at a first baking temperature of not less than the melting point of the first fluorocarbon resin and less than the decomposition temperature of the first fluorocarbon resin to enhance the rigidity of the conductive porous substrate.

Abstract: By using a gas diffusion layer for a fuel cell comprising a fabric comprising a warp thread and a weft thread which are made of carbon fiber, wherein the distance X between adjacent intersections where the warp and weft threads cross each other and the thickness Y of the fabric satisfy the equation: 1.4?X/Y?3.5, the present invention reduces the surface asperities of the substrate and prevents a micro short-circuit resulting from the piercing of the polymer electrolyte membrane of the fuel cell by the carbon fibers of the fabric so as to improve the characteristics of the fuel cell.

Abstract: The present invention restores the performance of a fuel cell by: operating the cell in a loaded current mode different from that of a normal operation for a predetermined time; supplying an oxidant gas and a fuel gas to an anode and a cathode respectively and outputting a current from a cell body with the polarity being inverted; supplying a pressurized gas to at least one of the cathode and anode in an amount not less than 1.5 times as much as that in the normal operation or supplying oxygen to the cathode; or injecting a cleaning solution into the cathode and anode through a gas flow path. Consequently, it is possible to effectively restore a degraded performance of a polymer electrolyte fuel cell caused by a long operation.

Abstract: A fuel cell system is disclosed, including a fuel cell configured to generate an electric power using a fuel gas and an oxidizing gas supplied to the fuel cell, and a total enthalpy heat exchanger configured to heat and humidify the oxidizing gas using heat and water exhausted from the fuel cell, wherein the total enthalpy heat exchanger is capable of removing impurities contained in the oxidizing gas from the oxidizing gas.

Abstract: A polymer electrolyte fuel cell stack that includes a cell laminate having a plurality of unit cells, which are laid one upon another and each of which includes a polymer electrolyte membrane, a pair of electrodes arranged across the polymer electrolyte membrane and having respective catalytic reaction layers, a separator having means for feeding a supply of fuel gas containing hydrogen gas to one of the electrodes, another separator having means for feeding a supply of oxidant gas to the other of the electrodes, and a manifold for feeding the supply of fuel gas or the supply of oxidant gas to the respective electrode and disposed on a side face of each unit cell. In the polymer electrolyte fuel cell stack, a sealing portion is disposed at least in the vicinity of each electrode. The polymer electrolyte fuel cell stack has excellent durability and productivity.

Abstract: An electrolyte fuel system, its operation and program and a recording medium associated with the program is disclosed. Embodiments include a fuel cell system having a load electric current changing means for changing an amount of load electric current that runs in one ore more fuel cells which are operated to generate electricity, a measurement means for measuring voltage responses to the change in said load electric current, a calculating means for calculating impedance of said one or more fuel cells based on said voltage responses measured, and a fuel cell control means for controlling condition for operation of said one or more fuel cells by utilizing calculation results retrieved by said calculating means.

Abstract: The present invention provides a gas-permeable hollow fiber membrane having an inner diameter of 50 to 500 ?m and a membrane thickness of 10 to 150 ?m, which is preferably a composite hollow fiber membrane having a three-layer structure consisting of a nonporous layer having porous layers disposed on both sides thereof. Dissolved gases present in an ink can be removed by passing the ink through the bores of hollow fibers comprising such a hollow fiber membrane, and evacuating the outer surface side of the hollow fibers. This method makes it possible not only to degas inks with a slight pressure loss, but also to degas inks stably even if pressure changes occur during degassing.

Abstract: The present invention provides a gas-permeable hollow fiber membrane having an inner diameter of 50 to 500 ?m and a membrane thickness of 10 to 150 ?m, which is preferably a composite hollow fiber membrane having a three-layer structure consisting of a nonporous layer having porous layers disposed on both sides thereof. Dissolved gases present in an ink can be removed by passing the ink through the bores of hollow fibers comprising such a hollow fiber membrane, and evacuating the outer surface side of the hollow fibers. This method makes it possible not only to degas inks with a slight pressure loss, but also to degas inks stably even if pressure changes occur during degassing.

Abstract: A method for producing a membrane electrode assembly 1 for solid polymer electrolyte fuel cell, the membrane electrode assembly 1 including a solid polymer electrolyte membrane 2 comprising an ion exchange membrane, a first electrode 3 having a first catalyst layer 31, and a second electrode 4 having a second catalyst layer 41, the first electrode 3 and the second electrode 4 being disposed so as to be opposed to each other via the ion exchange membrane, the method including: applying a coating solution containing a catalyst onto a base film 101 to form a first catalyst layer 31; applying a coating solution containing an ion exchange resin dissolved or dispersed in a liquid onto the first catalyst layer 31 to form an ion exchange membrane; then applying a coating solution containing a catalyst onto the ion exchange membrane to form a second catalyst layer 41; and finally, peeling off the base film 101 from a resulting laminate.

Abstract: A polymer electrolyte fuel cell stack that includes a cell laminate having a plurality of unit cells, which are laid one upon another and each of which includes a polymer electrolyte membrane, a pair of electrodes arranged across the polymer electrolyte membrane and having respective catalytic reaction layers, a separator having means for feeding a supply of fuel gas containing hydrogen gas to one of the electrodes, another separator having means for feeding a supply of oxidant gas to the other of the electrodes, and a manifold for feeding the supply of fuel gas or the supply of oxidant gas to the respective electrode and disposed on a side face of each unit cell. In the polymer electrolyte fuel cell stack, a sealing portion is disposed at least in the vicinity of each electrode. The polymer electrolyte fuel cell stack has excellent durability and productivity.

Abstract: A fuel cell is disclosed having a separator that can minimize damage to a membrane electrode assembly. The separator advantageously has a groove therein approximately positioned over an outer edge of an electrode of the fuel cell to reduce any pressure between the separator and the outer edge of the electrode upon assembly and during use thereafter.

Abstract: An air purifying apparatus for a fuel cell is provided on a flow route of air supplied to the fuel cell. The air purifying apparatus includes a first pollutant-removing means that oxidizes a pollutant in the air and a second pollutant-removing means that adsorbs and removes the pollutant. The first pollutant-removing means includes a catalyst that oxidizes the pollutant by means of oxygen in the air, and the catalyst has an oxidizing activity with respect to at least one selected from the group consisting of organic substances, nitrogen oxides, sulfur oxides, ammonia, hydrogen sulfide, and carbon monoxide. The first pollutant-removing means may include an ozone generator. The second pollutant-removing means adsorbs and removes the pollutant by means of a porous material carrying at least one selected from the group consisting of permanganates, alkali salts, alkaline hydroxides, and alkaline oxides.

Abstract: The present invention provides a gas-permeable hollow fiber membrane having an inner diameter of 50 to 500 &mgr;m and a membrane thickness of 10 to 150 &mgr;m, which is, preferably a composite hollow fiber membrane having a three-layer structure consisting of a nonporous layer having porous layers disposed on both sides thereof. Dissolved gases present in an ink can be removed by passing the ink through the bores of hollow fibers comprising such a hollow fiber membrane, and evacuating the outer surface side of the hollow fibers. This method makes it possible not only to degas inks with a slight pressure loss, but also to degas inks stably even if pressure changes occur during degassing.

Abstract: The present specification discloses a polymer electrolyte fuel cell characterized in that each of the cathode and the anode comprises catalyst particles, a hydrogen ion-conductive polymer electrode, a conductive porous base material and a water repellent agent, and water repellency of at least one of the cathode and the anode varies in a direction of thickness or in a plane direction. As such, by varying the degree of the water repellency of the cathode and the anode on the basis of a position, an excellent polymer electrolyte fuel cell having a high discharge characteristic or more specifically a high current-voltage characteristic in a high current density range.

Abstract: An electrolyte membrane-electrode assembly for a fuel cell includes a polymer electrolyte membrane and a pair of electrodes sandwiching the electrolyte membrane. Each of the electrodes includes a catalyst layer in contact with the polymer electrolyte membrane and a gas diffusion layer in contact with the catalyst layer, and the polymer electrolyte membrane includes electronically insulating particles, which serve as spacers for separating the gas diffusion layers of the electrodes, in a region sandwiched between the electrodes.

Abstract: A coke oven and a method of operating the same, capable not only of achieving a uniform combustion temperature heightwise within a combustion chamber when a rich gas or a lean gas is burnt, but also of reducing NOx content in the waste gas, while eliminating localized high-temperature combustion. The combustion chamber of the coke oven comprises a rich-gas port 2 located near an oven wall 6 bordering a carbonization chamber in the bottom 5 of combustion chamber, and the midpoint P3, connecting the center P2 of a lean-gas port 7 and the center P of an air port 3, is on the side opposite to the rich-gas port 2 relative to the center line CL of the combustion chamber. (See FIG.

Abstract: A polymer electrolyte fuel cell exhibits an excellent performance with an efficient electrode reaction: by providing a layer containing an electroconductive fine particle between the catalytic reaction layer and the gas diffusion layer in the electrodes; by providing a hydrogen ion diffusion layer on at least either surface of the catalyst particle or the carrier, which carries the catalyst particle in the catalytic reaction layer; or by constituting the catalytic reaction layer with at least a catalyst comprising a hydrophilic carbon material with catalyst particles carried thereon and a water repellent carbon material.

Abstract: The invention relates to methods of operating a fuel cell capable of suppressing degradation of a fuel cell caused by starting and stopping of the fuel cell, and to fuel cell systems for carrying out the method.