An object of the present invention is to provide a nonwoven carbon fiber fabric suitable as a gas diffusion electrode, which achieves good water discharge performance and maintains high gas diffusibility even when electricity is generated in humid conditions. The present invention provides a nonwoven carbon fiber fabric which has ridges on at least one surface thereof and which is provided with a water repellent, the ridges having a pitch that is less than 500 μm.

In a fuel cell separator comprising gas flow channels composed of a plurality of concavoconvex parts in the center region and flat parts on the periphery of the gas flow channels, the fuel cell separator provided with the first bent parts that bend approximately vertically to the same direction respectively at both edge parts at least in one direction among on flat parts in both directions of gas flow channels, and the second bent parts between gas flow channel-side flat parts and edge-side flat parts on the flat parts in the inward from the first bent parts on both sides with a smoothly curved cross-sectional shape of the gas flow channel-side bent ends of the second bent parts, and the production method thereof.

In a fuel cell separator comprising gas flow channels composed of a plurality of concavoconvex parts in the center region and flat parts on the periphery of the gas flow channels, the fuel cell separator provided with the first bent parts that bend approximately vertically to the same direction respectively at both edge parts at least in one direction among on flat parts in both directions of gas flow channels, and the second bent parts between gas flow channel-side flat parts and edge-side flat parts on the flat parts in the inward from the first bent parts on both sides with a smoothly curved cross-sectional shape of the gas flow channel-side bent ends of the second bent parts, and the production method thereof.

A fuel cell includes a resin-framed membrane electrode assembly, first and second separators, and a resin frame member. The resin frame member is provided to surround an outer periphery of a solid polymer electrolyte membrane. The first and second separators sandwich the resin-framed membrane electrode assembly therebetween in a stacking direction to define a reactant gas flow channel between each of the first and second separators and the resin-framed membrane electrode assembly. The first and second separators include a reactant gas manifold hole which passes through the first and second separators in the stacking direction. The resin frame member includes a bridge portion having connecting flow channels connecting the reactant gas flow channel and the reactant gas manifold hole. At least one of the connecting flow channels has a sloped surface.

A fuel cell includes a resin-framed membrane electrode assembly, first and second separators, and a resin frame member. The resin frame member is provided to surround an outer periphery of a solid polymer electrolyte membrane. The first and second separators sandwich the resin-framed membrane electrode assembly therebetween in a stacking direction to define a reactant gas flow channel between each of the first and second separators and the resin-framed membrane electrode assembly. The first and second separators include a reactant gas manifold hole which passes through the first and second separators in the stacking direction. The resin frame member includes a bridge portion having connecting flow channels connecting the reactant gas flow channel and the reactant gas manifold hole. At least one of the connecting flow channels has a sloped surface.

A flow field plate comprises a first flow field; an opposing second flow field; and at least one flow channel formed in the first flow field, the at least one flow channel comprising: a first side and an opposing second side separated by an open-faced top and a bottom; and a first side channel formed in a portion of the open-faced top and in a portion of the first side along a continuous length of the at least one flow channel, the first side channel comprising a first side wall and a first bottom wall; wherein the first side wall of the first side channel and the first bottom wall of the first side channel form an obtuse angle in cross-section; and a depth of the bottom of the at least one flow channel is greater than a depth of the bottom wall of the first side channel.

A flow field plate comprises a first flow field; an opposing second flow field; and at least one flow channel formed in the first flow field, the at least one flow channel comprising: a first side and an opposing second side separated by an open-faced top and a bottom; and a first side channel formed in a portion of the open-faced top and in a portion of the first side along a continuous length of the at least one flow channel, the first side channel comprising a first side wall and a first bottom wall; wherein the first side wall of the first side channel and the first bottom wall of the first side channel form an obtuse angle in cross-section; and a depth of the bottom of the at least one flow channel is greater than a depth of the bottom wall of the first side channel.

A separator for a fuel cell includes a thin metal plate, protrusions that are formed on the metal plate to be close to each other, and gas passages formed by the protrusions. Each gas passage has a first opening corresponding to an inlet and a second opening corresponding to an outlet. The gas passages include a first gas passage, which has a relatively low pressure loss of gas flow, and a second gas passage, which has a relatively high pressure loss of gas flow. The area of the first opening of the first gas passage is set to be smaller than the area of the first opening of the second gas passage.

An electrochemical device includes: an electrolyte membrane; an anode disposed on a first main surface of the electrolyte membrane; a cathode disposed on a second main surface of the electrolyte membrane; an anode separator disposed on the anode; and a cathode separator disposed on the cathode and including a first conductive layer on a surface adjacent to the cathode. The cathode includes a cathode gas diffusion layer. The cathode separator has a recess for storing the cathode gas diffusion layer. The first conductive layer is disposed only on a bottom surface of the recess.

An electrochemical device includes: an electrolyte membrane; an anode disposed on a first main surface of the electrolyte membrane; a cathode disposed on a second main surface of the electrolyte membrane; an anode separator disposed on the anode; and a cathode separator disposed on the cathode and including a first conductive layer on a surface adjacent to the cathode. The cathode includes a cathode gas diffusion layer. The cathode separator has a recess for storing the cathode gas diffusion layer. The first conductive layer is disposed only on a bottom surface of the recess.