Abstract: A fuel cell includes a membrane electrode assembly and a separator. The separator includes a water accumulation portion including at least one of a buffer portion, a lowermost channel groove, a channel junction portion, and a bypass channel. The buffer portion is connected to a reactant gas channel through which a reactant gas is to flow along a power generation surface of the membrane electrode assembly. The channel groove is provided in the reactant gas channel and located at a lowest position in the reactant gas channel in a direction of gravity when the membrane electrode assembly and the separator are in an upright position. Channel grooves of the reactant gas channel are joined in the channel junction portion. The membrane electrode assembly includes a water impermeable layer which is disposed outside of a power generation region and which faces the water accumulation portion.

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 an electrolyte-electrode assembly, a frame member, a first separator, and a second separator. The frame member is provided to face a first surface of the second separator and includes a resin wall which forms a periphery of a first reactant gas passage. The resin wall has a thin-walled portion which overlaps with a cooling medium connecting portion in a stacking direction and which protrudes toward the first reactant gas passage in the stacking direction by a first dimension from a surface of the frame member. Another portion of the resin wall protrudes toward the second separator in the stacking direction by a second dimension from the surface of the frame member. The first dimension is smaller than the second dimension.

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 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 solid polymer electrolyte membrane, an anode electrode, and a cathode electrode. The resin frame member surrounds an outer periphery of the solid polymer electrolyte membrane and includes an inner protruding portion that protrudes from an inner peripheral base portion toward the cathode electrode and that has a thickness. The inner protruding portion has an adhesive application portion to which an adhesive is applied so as to surround a part of the inner protruding portion. The part is in contact with the stepped membrane electrode assembly. A thickness of a cathode diffusion layer is larger than a thickness of an anode diffusion layer.

Abstract: A fuel cell stack comprising a second metal separator set to have an external dimension larger than a first metal separator, wherein the second metal separator comprises, formed integrally, a first seal member in contact with the peripheral edge of a first electrolyte membrane/electrode structure, a second seal member in contact with the peripheral edge of the first metal separator, and a third seal member in contact with the peripheral edge of an adjoining fourth metal separator. Since the first seal member, the second seal member and the third seal member are integrally formed on one surface of the second separator or one surface of the first separator, a seal-forming step can be carried out at one effort, simply and economically. In addition, use of a triple seal structure containing the first through the third seal members can favorably improve the sealing feature of reaction gas and minimize reaction gas leakage.

Abstract: A fuel cell includes a membrane electrode assembly and separators, an inner sealing member and an outer sealing member, a coolant channel, a base seal, an inner protrusion and an outer protrusion, and a middle protrusion. The membrane electrode assembly and the separators are stacked in a stacking direction. The inner sealing member and the outer sealing member are disposed between a first separator and a second separator. The base seal is disposed on at least one of separator surfaces between the second separator and a third separator. The inner protrusion and the outer protrusion are provided on the base seal so as to respectively overlap the inner sealing member and the outer sealing member when viewed in the stacking direction and so as to protrude between the second separator and the third separator in the stacking direction.

Abstract: A fuel cell includes a membrane electrode assembly, a first separator, and a second separator. The membrane electrode assembly includes a solid polymer electrolyte membrane, a first electrode, a second electrode, and a resin frame member. The membrane electrode assembly includes a power generation section and a stepped section. The power generation section is located in an interior space of the resin frame member. The solid polymer electrolyte membrane is provided between the first electrode and the second electrode in the power generation section. The stepped section is located on an outer side of the first electrode. The solid polymer electrolyte membrane is provided between the second electrode and the resin frame member in the stepped section. A magnitude of an interference in the stepped section is set to be smaller than a magnitude of an interference in the power generation section.

Abstract: A resin frame equipped membrane electrode assembly includes a membrane electrode assembly and a resin frame member. The membrane electrode assembly includes a solid polymer electrolyte membrane and an anode, and a cathode sandwiching the solid polymer electrolyte membrane. The resin frame member is formed around the solid polymer electrolyte membrane. The outer end of an electrode catalyst layer of the cathode protrudes beyond the outer end of a gas diffusion layer, and the resin frame member includes an inner extension protruding toward the outer periphery of the cathode to contact the outer end of the solid polymer electrolyte membrane. The inner extension of the resin frame member has an overlapped portion overlapped with the outer end of the electrode catalyst layer.

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 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 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 fuel cell stack comprising a second metal separator set to have an external dimension larger than a first metal separator, wherein the second metal separator comprises, formed integrally, a first seal member in contact with the peripheral edge of a first electrolyte membrane/electrode structure, a second seal member in contact with the peripheral edge of the first metal separator, and a third seal member in contact with the peripheral edge of an adjoining fourth metal separator. Since the first seal member, the second seal member and the third seal member are integrally formed on one surface of the second separator or one surface of the first separator, a seal-forming step can be carried out at one effort, simply and economically. In addition, use of a triple seal structure containing the first through the third seal members can favorably improve the sealing feature of reaction gas and minimize reaction gas leakage.

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 an electrolyte-electrode assembly, a frame member, a first separator, and a second separator. The frame member is provided to face a first surface of the second separator and includes a resin wall which forms a periphery of a first reactant gas passage. The resin wall has a thin-walled portion which overlaps with a cooling medium connecting portion in a stacking direction and which protrudes toward the first reactant gas passage in the stacking direction by a first dimension from a surface of the frame member. Another portion of the resin wall protrudes toward the second separator in the stacking direction by a second dimension from the surface of the frame member. The first dimension is smaller than the second dimension.

Abstract: A unit cell of a fuel cell is formed by stacking a membrane electrode assembly between a first metal separator and a second metal separator in a stacking direction. A frame is provided in an outer end of the membrane electrode assembly. A seal member is formed on the frame. The seal member includes a first seal as a fuel gas seal, a second seal as a coolant seal, and a third seal as an oxygen-containing gas seal. The first seal, the second seal, and the third seal are offset from each other in the stacking direction.

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 and a separator. The separator includes a water accumulation portion including at least one of a buffer portion, a lowermost channel groove, a channel junction portion, and a bypass channel. The buffer portion is connected to a reactant gas channel through which a reactant gas is to flow along a power generation surface of the membrane electrode assembly. The channel groove is provided in the reactant gas channel and located at a lowest position in the reactant gas channel in a direction of gravity when the membrane electrode assembly and the separator are in an upright position. Channel grooves of the reactant gas channel are joined in the channel junction portion. The membrane electrode assembly includes a water impermeable layer which is disposed outside of a power generation region and which faces the water accumulation portion.

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: A fuel cell stack comprising a second metal separator set to have an external dimension larger than a first metal separator, wherein the second metal separator comprises, formed integrally, a first seal member in contact with the peripheral edge of a first electrolyte membrane/electrode structure, a second seal member in contact with the peripheral edge of the first metal separator, and a third seal member in contact with the peripheral edge of an adjoining fourth metal separator. Since the first seal member, the second seal member and the third seal member are integrally formed on one surface of the second separator or one surface of the first separator, a seal-forming step can be carried out at one effort, simply and economically. In addition, use of a triple seal structure containing the first through the third seal members can favorably improve the sealing feature of reaction gas and minimize reaction gas leakage.