Abstract: A fuel cell includes a membrane electrode assembly interposed between a cathode-side separator and an anode-side separator. A first gas diffusion layer included in a cathode is designed to have a planar size larger than a planar size of a second gas diffusion layer included in an anode. The anode-side separator has a thin clearance part in a portion that faces an outer peripheral portion of the second gas diffusion layer.

Abstract: A resin-framed stepped membrane electrode assembly for a fuel cell, includes a stepped membrane electrode assembly and a resin frame member. The resin frame member surrounds a membrane outer periphery end of a solid polymer electrolyte membrane and includes an inner protruding portion protruding from the membrane outer periphery end toward a second electrode and is joined to the stepped membrane electrode assembly with an adhesive. The inner protruding portion includes a bank portion, a groove portion, and a ledge portion. The roughness of the bank surface is smaller than a roughness of the groove surface.

Abstract: A cell unit constituting a fuel cell is provided with a first electrolyte membrane/electrode structure, a first separator, a second electrolyte membrane/electrode structure, and a second separator. The first and second electrolyte membrane/electrode structures respectively have a frame section on the outer periphery, and the frame sections are formed with a fluid communicating hole extending in the stacking direction. The first and second separators are disposed towards the inside of the fluid communication hole and are respectively provided with two metal plates which have the same shape and which are stacked on one another.

Abstract: An oxidant gas conduit communicating with both an oxidant gas inlet communication hole and an oxidant gas outlet communication hole is formed in a surface of a cathode-side metallic separator which forms a fuel cell. Continuous linear guide ridges which protrude from intermediate height sections to the oxidant gas conduit side and form continuous guide conduits are provided on the cathode-side metallic separator. The linear guide ridges are continuously connected to ends of rectilinear conduit ridges which form rectilinear conduits, are provided with bend portions, and are set to lengths which are different from each other in a step-like manner.

Abstract: In a power generation unit of a fuel cell stack, bosses of a first metal separator and bosses of a second metal separator are provided to sandwich a first membrane electrode assembly at first sandwiching positions on both sides of the first membrane electrode assembly, oppositely to each other in a stacking direction. Bosses of a second metal separator and bosses of a third metal separator are provided to sandwich a second membrane electrode assembly at second sandwiching positions on both sides of the second membrane electrode assembly, oppositely to each other in the stacking direction. Bosses of the first metal separator and bosses of the third metal separator protrude toward a coolant flow field, and contact each other at positions offset from the first and second sandwiching positions.

Abstract: A solid polymer electrolyte membrane is made from a solid polymer electrolyte membrane roll in which a solid polymer electrolyte membrane sheet is wound in a winding direction. A first electrode is disposed on a first surface of the solid polymer electrolyte membrane in a stacking direction. A second electrode is disposed on a second surface of the solid polymer electrolyte membrane in the stacking direction and has a size smaller than a size of the first electrode viewed in the stacking direction. A resin frame member has a rectangular peripheral shape and a rectangular window therein viewed in the stacking direction. The rectangular stepped membrane electrode assembly is provided in the rectangular window so that the outer peripheral surface of the solid polymer electrolyte membrane is surrounded by the resin frame member. The rectangular peripheral shape has a longitudinal side which extends in the winding direction.

Abstract: Disclosed is a fuel cell in which an electrolyte membrane-electrode structure is held between the first separator and a second separator. The electrolyte membrane-electrode structure comprises a solid polymer electrolyte membrane, a cathode-side electrode and an anode-side electrode. An end portion of the solid polymer electrolyte membrane projects outwardly beyond end portions of gas diffusion layers, and the both surfaces of the end portion of the solid polymer electrolyte membrane are held between the first protective film and a second protective film. The thickness of the first protective film is set to be thinner than the thickness of the second protective film.

Abstract: A resin frame member of a resin frame equipped membrane electrode assembly includes a recess where adhesive is provided. An inner protrusion on an inner side of the recess abuts against an electrode catalyst layer protruding outward beyond a gas diffusion layer of a membrane electrode assembly. An outer protrusion on an outer side of the recess abuts against the outermost portion of a gas diffusion layer of the membrane electrode assembly such that a solid polymer electrolyte membrane is interposed between the outer protrusion and the gas diffusion layer.

Abstract: A resin frame equipped membrane electrode assembly includes an MEA having different sizes of components and a resin frame member. A clearance is formed between an outer end of a second gas diffusion layer and an inner expansion. The second electrode layer has a frame shaped outer marginal portion provided at the clearance. The crack density of cracks of the frame shaped outer marginal portion is 30 cracks/mm2 or less, and the interval between the cracks is 0.06 mm or more.

Abstract: A fuel cell stack includes a first power generation unit and a second power generation unit. Wave-like first fuel gas flow passages of the first power generation unit and wave-like first fuel gas flow passages of the second power generation unit are set to mutually different phases. The ends of the first fuel gas flow passages form linear flow passage grooves that linearly extend in the wavelength direction from the center of the width of the wave-form amplitude.

Abstract: A power generation unit of a fuel cell includes a first metal separator, a first membrane electrode assembly, a second metal separator, a second membrane electrode assembly, and a third metal separator. A bypass limiting section is provided at an end of the coolant flow field for preventing a coolant from bypassing the coolant flow field. The bypass limiting section includes a corrugated section formed integrally with the first metal separator and a corrugated section formed integrally with the third metal separator adjacent to the first metal separator, and contacting the corrugated section.

Abstract: A fuel cell includes a membrane electrode assembly, separators, and a second separator among the separators. The membrane electrode assembly includes an electrolyte membrane, a first electrode and a second electrode, and a resin frame member. A first separator among the separators facing the first electrode includes a fuel gas channel, a fuel gas manifold, and a fuel gas buffer. The second separator among the separators facing the second electrode includes an oxidant gas channel, an oxidant gas manifold, and an oxidant gas buffer. The fuel gas buffer includes a first fuel gas buffer region and a second fuel gas buffer region. The second fuel gas buffer region is more deeply grooved than the first fuel gas buffer region in a stacking direction. The oxidant gas buffer includes a first oxidant gas buffer region and a second oxidant gas buffer region.

Abstract: A first sealing member includes a first flat sealing portion facing a first electrode, a second flat sealing portion, and a first protruding sealing portion. The second flat sealing portion is opposite to the first electrode in the stacking direction. The first protruding sealing portion protrudes from the second flat sealing portion in the stacking direction and includes a crossing portion at which the first protruding sealing portion diverges. A second sealing member includes a third flat sealing portion facing a second electrode, a second protruding sealing portion, and a block-shaped seal. The second protruding sealing portion protrudes from the third flat sealing portion in the stacking direction. The block-shaped seal is disposed in a region corresponding to the crossing portion viewed in a stacking direction and protruding from the third flat sealing portion apart from the second protruding sealing portion.

Abstract: A fuel cell stack includes a first power generation unit and a second power generation unit. Wave-like first fuel gas flow passages of the first power generation unit and wave-like first fuel gas flow passages of the second power generation unit are set to mutually different phases. The ends of the first fuel gas flow passages form linear flow passage grooves that linearly extend in the wavelength direction from the center of the width of the wave-form amplitude.

Abstract: A unit cell of a fuel cell stack includes separators. Load receivers provided in the separators include projections, for example. The proximal ends of the projections are depressed to form inner curves. In the structure, sufficient flexibility of the projection is achieved. That is, when a force in a direction perpendicular to a stacking direction of fuel cell stack is applied to the projection, the projection is deformed in the direction perpendicular to the stacking direction.

Abstract: A resin-framed membrane-electrode assembly for a fuel cell includes a stepped membrane-electrode assembly and a resin frame member. The stepped membrane-electrode assembly includes a polymer electrolyte membrane, a first electrode, and a second electrode. The resin frame member surrounds an outer perimeter of the polymer electrolyte membrane and includes an inner perimeter base end and an inner protruding portion. The inner protruding portion includes a flat surface portion which extends to face an outer perimeter surface portion of a second surface of the polymer electrolyte membrane and on which an adhesive layer is provided so that the adhesive layer lies at least between the flat surface portion and the outer perimeter surface portion. The adhesive layer has a tapered shape in which a thickness of the adhesive layer increases from a tip of the inner protruding portion toward the inner perimeter base end.

Abstract: A fuel cell includes a membrane electrode assembly, a first separator, and a second separator. The second separator has a fuel gas flow field connected to a fuel gas supply passage and a fuel gas discharge passage. The fuel gas flow field includes a plurality of corrugated flow grooves and a flat flow field. The corrugated flow grooves extend in the horizontal direction, respectively, and are arranged in the direction of the gravity. The flat flow field is provided within a power generation area, at the lowermost position in the direction of the gravity, and extends in the horizontal direction.

Abstract: A fuel cell includes a cell unit. The cell unit includes a first separator, a second separator, and an electrolyte-electrode assembly. The electrolyte-electrode assembly is sandwiched between the first separator and the second separator in a stacking direction. The outer periphery of the electrolyte-electrode assembly is integrally provided with frame members composed of a polymer material. Fluid communication holes are provided as through holes in the stacking direction in each of the frame members. The seal member is sandwiched between the frame members that are adjacent to each other in the stacking direction. The first and second separators each have two plates with an identical outer shape. Each of the frame members has a rib projecting in a thickness direction of the frame member, at least around one of an outermost periphery of the frame member and the fluid communication holes.

Abstract: A fuel cell is formed by sandwiching a membrane electrode assembly between a first separator and a second separator. A fuel gas flow field is formed in the second separator. An inlet buffer is connected to the inlet of the fuel gas flow field, and an outlet buffer is connected to an outlet of the fuel gas flow field. The inlet buffer is deeper than the outlet buffer. Therefore, the pressure loss in the inlet buffer is smaller than the pressure loss in the outlet buffer.

Abstract: A power generation unit of a fuel cell includes a first metal separator, a first membrane electrode assembly, a second metal separator, a second membrane electrode assembly, and a third metal separator. A bypass limiting section is provided at an end of the coolant flow field for preventing a coolant from bypassing the coolant flow field. The bypass limiting section includes a corrugated section formed integrally with the first metal separator and a corrugated section formed integrally with the third metal separator adjacent to the first metal separator, and contacting the corrugated section.