Abstract: A direct oxidation fuel cell of this invention has at least one unit cell including: a membrane-electrode assembly comprising an electrolyte membrane sandwiched between an anode and a cathode, each of the anode and the cathode including a catalyst layer and a diffusion layer; an anode-side separator with a fuel flow channel for supplying a fuel to the anode; and a cathode-side separator with an oxidant flow channel for supplying an oxidant containing oxygen gas to the cathode. The fuel flow channel and the oxidant flow channel are so structured that the concentration of the oxygen gas in the oxidant flow channel is higher at a part opposing an upstream part of the fuel flow channel than at a part opposing a downstream part of the fuel flow channel.

Abstract: A membrane electrode assembly for a fuel cell includes an anode, a cathode, and an electrolyte membrane disposed between the anode and the cathode. The cathode includes a cathode catalyst layer and a cathode diffusion layer disposed on the cathode catalyst layer. The cathode diffusion layer includes a conductive porous substrate and a porous composite layer disposed on a surface of the conductive porous substrate. The porous composite layer includes conductive carbon particles and a water-repellent binding material. The cathode diffusion layer has a plurality of through pores having a largest pore diameter of 15 to 20.5 ?m and a mean flow pore diameter of 3 to 10.5 ?m in pore throat size distribution determined by a half dry/bubble point method.

Abstract: A method for operating a fuel cell system including a fuel cell stack composed of a plurality of cells connected in series. The method includes the steps of: (a) supplying a fuel and an oxidant to anodes and cathodes of the cells, respectively, depending on a load to generate power at a constant voltage under constant voltage control; (b) temporarily suspending the supply of the oxidant with the fuel being supplied; and (c) lowering the constant voltage to a predetermined voltage simultaneously with or immediately before the suspension of the supply of the oxidant. According to this operation method, when the supply of the oxidant is suspended, a platinum catalyst in the cathodes can be reduced and reactivated in all the cells.

Abstract: A direct oxidation fuel cell of this invention has at least one unit cell including: a membrane-electrode assembly including an electrolyte membrane sandwiched between an anode and a cathode, each of the anode and the cathode including a catalyst layer and a diffusion layer; an anode-side separator with a fuel flow channel for supplying a fuel to the anode; and a cathode-side separator with an oxidant flow channel for supplying an oxidant to the cathode. The catalyst layer of at least one of the anode and the cathode includes high-porosity regions and low-porosity regions, and the high-porosity regions and the low-porosity regions are arranged in a mixed configuration.

Abstract: A library control device to controls a library device includes a designated-information acquisition section, a loading control section, a transfer control section and a medium storage control section. The transfer control section that orders, when a storage location indicated by the loading control section to a library device and a storage location designated by storage-location designating information are different from each other, the library device to transfer a storage medium from the storage location designated by the storage-location designating information to a storage location different from the storage location designated by the storage-location designating information.

Abstract: A fuel container for storing a fuel liquid for a fuel cell has a double wall structure including an inner container for storing a fuel liquid and an outer container for housing the inner container, and a material capable of retaining the fuel between the inner container and the outer container. A fuel cell pack includes a fuel cell and a fuel container for storing a fuel liquid for the fuel cell. The fuel cell pack includes a double wall exterior casing having an inner casing for housing the fuel cell and the fuel container and an outer casing for housing the inner casing, and a material capable of retaining the fuel between the inner casing and the outer casing.

Abstract: A fuel cell system includes a fuel cell including at least one unit cell having an anode, an anode-side flow channel for supplying a fuel to the anode, a cathode, and a cathode-side flow channel for supplying an oxidant to the cathode. The fuel cell system further includes a gas-liquid separator for catalytically purifying the effluent from the anode and the effluent from the cathode to collect liquid. The gas-liquid separator is connected to an anode-side discharge path for the effluent and a cathode-side discharge path for the effluent, which are in fluid communication with a fuel outlet of the anode-side flow channel and an oxidant outlet of the cathode-side flow channel, respectively.

Abstract: A direct methanol fuel cell has at least one cell including a membrane electrode assembly. The membrane electrode assembly includes an anode, a cathode, and a polymer electrolyte membrane disposed between the anode and the cathode. The cathode includes a cathode catalyst layer in contact with the polymer electrolyte membrane, and a cathode diffusion layer in contact with the cathode catalyst layer. The cathode catalyst layer includes a cathode catalyst, a catalyst support on which the cathode catalyst is supported, and a polymer electrolyte. The weight ratio of the polymer electrolyte to the catalyst support is from 0.2 to 0.55. The cathode catalyst layer in a dry state has a porosity of 50% to 85%.

Abstract: An anode electrode for use in a fuel cell comprises a stacked structure including, in sequence: a catalyst layer, a hydrophobic, microporous layer (“MPL”), a porous gas diffusion layer (“GDL”), and an anode plate with at least one recessed fuel supply-fuel/gas exhaust channel formed in a surface thereof facing the GDL, wherein the stacked structure further comprises at least one hydrophobic region aligned with the at least one recessed channel. The electrode is useful in direct oxidation fuel cells and systems, such as direct methanol fuel cells operating with highly concentrated liquid fuel.

Abstract: A membrane electrode assembly for a direct oxidation fuel cell includes an electrolyte membrane, an anode disposed on one face of the electrolyte membrane, and a cathode disposed on the other face of the electrolyte membrane. The cathode includes a cathode catalyst layer with a first main surface and a second main surface, and the cathode catalyst layer includes a cathode catalyst and a polymer electrolyte. The cathode catalyst layer includes a plurality of first regions and a plurality of second regions, and the first regions and the second regions are different in polymer electrolyte content. The polymer electrolyte content in each of the second regions is lower than the polymer electrolyte content in each of the first regions. The second regions are continuous from the first main surface of the cathode catalyst layer to the second main surface.

Abstract: A direct methanol fuel cell of the present invention includes a unit cell having an electrolyte membrane, an anode on one surface of the electrolyte membrane, and a cathode on the other surface of the electrolyte membrane. The anode includes an anode catalyst layer and an anode diffusion layer. The anode catalyst layer is in contact with a surface of the electrolyte membrane. The anode diffusion layer is in contact with a surface of the anode catalyst layer opposite to the surface of the anode catalyst layer in contact with the electrolyte membrane. A methanol flux value JGDL of the anode diffusion layer and a methanol flux value JPEM of the electrolyte membrane satisfy the following relations: JGDL=1×10?5 to 5×10?4 mol/(cm2·min.),??(i) and JPEM×JGDL?1×10?8 [mol/(cm2·min.)]2.

Abstract: The fuel cell of this invention includes at least one unit cell that includes: a membrane-electrode assembly including an electrolyte membrane sandwiched between an anode and a cathode; an anode-side separator in contact with the anode and having a fuel flow path for supplying a fuel to the anode; and a cathode-side separator in contact with the cathode and having an oxidant flow path for supplying an oxidant to the cathode. The fuel flow path has a first flow channel and a second flow channel, and each of the first flow channel and the second flow channel has a fuel inlet and a fuel outlet. The first flow channel and the second flow channel are adjacent to each other, and the direction of the flow of fuel through the first flow channel is opposite to the direction of the flow of fuel through the second flow channel.

Abstract: To prevent the flooding phenomenon at the cathode in a unit cell where the temperature is relatively low or the supply of air is small, a fuel cell stack includes at least three flat unit cells stacked with separators interposed therebetween, the unit cells comprising an anode, a cathode and an electrolyte membrane sandwiched therebetween, and having an oxidant channel formed on the surface of the separator adjacent to the cathode, and the anode and the cathode comprising a catalyst layer attached to the electrolyte membrane and a diffusion layer, wherein the cross-sectional area of the inlet side of the oxidant channel, the area of the cathode catalyst layer, the thickness of the electrolyte membrane or the amount of a water repellent contained in the combination of the cathode and the oxidant channel is the largest in at least one of the unit cells at the ends of the stack.

Abstract: A direct oxidation fuel cell includes at least one unit cell. The unit cell includes: a membrane electrode assembly including an anode, a cathode, and an electrolyte membrane sandwiched therebetween; an anode-side separator having a fuel flow channel for supplying a fuel to the anode; and a cathode-side separator having an oxidant flow channel for supplying an oxidant to the cathode. The cathode includes a cathode catalyst layer in contact with the electrolyte membrane, and a cathode diffusion layer in contact with the cathode-side separator. The cathode catalyst layer includes a cathode catalyst and a polymer electrolyte, and the amount of the polymer electrolyte contained in a portion of the cathode catalyst layer facing an upstream portion of the fuel flow channel is smaller than that contained in a portion of the cathode catalyst layer facing a downstream portion of the fuel flow channel.

Abstract: A fuel cell system includes: a fuel cell including an anode, a cathode, and an electrolyte interposed between the anode and the cathode; and a purifying apparatus including a catalyst layer that purifies an effluent discharged from the anode. The purifying apparatus has a porous sheet including the catalyst layer and two flow paths disposed on both sides thereof. One of the flow paths has an inlet into which the effluent discharged from the anode is introduced, and the other flow path has an inlet into which air is introduced and an outlet. The effluent discharged from the anode is passed through the porous sheet for purification and then discharged from the outlet.

Abstract: The direct oxidation fuel cell of the present invention is provided with: a membrane electrode assembly including an anode, a cathode, and an electrolyte membrane interposed between the anode and the cathode; an anode-side separator having a fuel flow channel for supplying fuel to the anode; and a cathode-side separator having an oxidant flow channel for supplying oxidant to the cathode, in which the anode includes an anode catalyst layer disposed at the side of the electrolyte membrane and an anode diffusion layer disposed at the side of the anode-side separator. The anode diffusion layer includes a water repellent layer disposed at the side of the anode catalyst layer and including a first conductive agent and a first water repellent agent; and a substrate layer disposed at the side of the anode-side separator, and the porosity of the substrate layer is higher at the downstream side than at the upstream side of the fuel flow.

Abstract: A fuel cell system includes a fuel cell stack for generating power and power generation control means. The fuel cell stack has at least one cell that includes a cathode to which an oxidant is supplied, an anode to which a fuel is supplied, and a polymer electrolyte membrane sandwiched between the cathode and the anode. The power generation control means has dryness degree determination means for determining the degree of dryness of the fuel cell stack based on shut-down period. When the shut-down period is shorter than a predetermined period of time, the power generation control means supplies a gas for drying to the cathode for a predetermined period of time, to remove water remaining in the cathode. When the shut-down period is equal to or longer than the predetermined period of time, such a drying operation is not performed.

Abstract: The direct oxidation fuel cell of the invention includes at least one unit cell, the unit cell including: a membrane-electrode assembly including an anode, a cathode, and an electrolyte membrane interposed therebetween; an anode-side separator; and a cathode-side separator. The cathode includes a first cathode catalyst layer, a diffusion layer being in contact with the cathode-side separator, and an intermediate layer disposed therebetween. The intermediate layer includes a second cathode catalyst layer and a porous composite layer, the porous composite layer containing a hydrophobic material and an electron-conductive material. The anode-side separator has a fuel flow channel, and the cathode-side separator has an oxidant flow channel.

Abstract: A fuel cell system includes: a dilute tank that stores an aqueous solution of liquid fuel and supplies the solution to the anode of a fuel cell; a fuel tank connected to the dilute tank via a first controlling section; a water tank connected to the dilute tank via a second controlling section; and controlling means including a current detector which measures the amount of the fuel consumed by the fuel cell from the amount of power generation. The controlling means controls the first controlling section based on the measured amount of fuel consumption and further includes correcting means for measuring a component of a gas discharged from the cathode, calculating the amount of the fuel which has crossed over from the anode to the cathode based on the measured component, and correcting the measured amount of fuel consumption based on the calculated amount of fuel crossover.

Abstract: A membrane-electrode assembly for a direct oxidation fuel cell includes an electrolyte membrane, and an anode and a cathode sandwiching said electrolyte membrane. The cathode includes a catalyst layer in contact with the electrolyte membrane and a diffusion layer formed on the catalyst layer, and the catalyst layer contains 2 to 20% by volume of pores. A direct oxidation fuel cell including this membrane-electrode assembly has excellent power generating performance and durability.