Abstract: A fuel cell is formed by stacking a plurality of unit cells. Each of the unit cells includes a membrane electrode assembly, and an anode side metal separator and a cathode side metal separator sandwiching the membrane electrode assembly therebetween. In a surface of the cathode side metal separator, metal portions are exposed in at least part of a second flat portion in an area surrounded by seal lines SL of the anode side metal separator. Cutouts are formed on a surface of the cathode side metal separator by cutting at least part of the second flat portion up to the metal portions thereby to expose the metal portions through the cutouts.

Abstract: A method of manufacturing a metal separator for a fuel cell includes providing an opening in a metal plate which is to be a part of the metal separator for the fuel cell, integrally molding a sealing member on both sides of an outer peripheral edge of the metal plate to cover the opening, and trimming the sealing member to remove a covering portion of the sealing member that covers the opening and to provide a fluid communication hole, at least one of a fuel gas, an oxidant gas, and a cooling medium being to pass through the fluid communication hole in the fuel cell.

Abstract: A fuel cell includes a frame equipped membrane electrode assembly and a metal separator. The frame equipped membrane electrode assembly includes a membrane electrode assembly and a frame shaped insulating member connected to the membrane electrode assembly. The frame shaped insulating member is provided around the membrane electrode assembly. The metal separator includes a first bipolar plate and a second bipolar plate joined together, and the frame shaped insulating member includes a welding portion welded to the first bipolar plate by resistance welding.

Abstract: A fuel cell stack and a method of assembling a fuel cell stack includes compressing fuel cells along their stacking axis. A compression retention device made up of an enclosure may be used with one or more optional insertable shims to correct for any stack height variations. Significantly, the enclosure is formed to allow the stack to be loaded in compression by a press such that the cells that make up the stack are placed into and maintained in a substantially compressed state while the compression force is not imparted to the enclosure. By resolving any stack height variances while the cells of the stack are maintained in their substantially compressed state, assembly operations are simplified in that repeated compression and decompression of the stack is avoided while trying to ensure that the stack and enclosure are joined into their final assembly form.

Abstract: A cell unit of a fuel cell includes a second separator. A first oxygen-containing gas flow field is formed on a surface of the second separator. An inlet buffer is connected to an inlet of the oxygen-containing gas flow field, and an outlet buffer is connected to an outlet of the first oxygen-containing gas flow field. The inlet buffer includes a first inlet buffer area having a deep groove and a second inlet buffer area, and the outlet buffer includes a first outlet buffer area having a deep groove and a second outlet buffer area. The first inlet buffer area and the first outlet buffer area have different surface areas.

Abstract: Coolant supply passages and coolant discharge passages, for example, two respectively thereof, are disposed on upper and lower side portions of a first end plate of a fuel cell stack. Grooves are formed on a surface of the first end plate for establishing communication between each of the coolant supply passages and the coolant discharge passages. Air, which is introduced upwardly of the coolant discharge passages, is discharged to the coolant supply passages.

Abstract: A fuel cell includes a membrane electrode assembly and a metal separator. The metal separator is stacked with the membrane electrode assembly. A reactant gas passage is provided between the membrane electrode assembly and the metal separator to supply a reactant gas along an electrode surface. The metal separator includes a reactant gas communication hole to communicate with the reactant gas passage. The metal separator further includes a plurality of groove groups each having a plurality of grooves press-formed to allow the reactant gas communication hole to communicate with the reactant gas passage. The grooves adjacent to each other are spaced apart by a first distance. The groove groups adjacent to each other are spaced apart by a second distance larger than the first distance.

Abstract: A fuel cell according to the present invention includes a power generation unit. The power generation unit is formed by stacking a first metal separator, a first membrane electrode assembly, a second metal separator, a second membrane electrode assembly, and a third metal separator. The number of flow grooves in a first oxygen-containing gas flow field is different from the number of flow grooves in a second oxygen-containing gas flow field. The first oxygen-containing gas flow field and the second oxygen-containing gas flow field have the same length, and the flow grooves in the first oxygen-containing gas flow field and the flow grooves in the second oxygen-containing gas flow field have the same depth.

Abstract: A fuel cell includes a membrane electrode assembly and a first separator. The first separator includes a first reactant gas channel, a first reactant gas manifold, and a first buffer portion. The first buffer portion is located outside of a power generation region of an electrode catalyst layer of the first electrode. The first buffer portion connects the first reactant gas channel to the first reactant gas manifold. A gas diffusion layer of the first electrode extends along a surface of the first separator to a first buffer region facing the first buffer portion. An intermediate layer of the first electrode covers a portion of the gas diffusion layer of the first electrode in the first buffer region.

Abstract: There has been a problem that the cell units cannot bear the load exerted on the units while being stacked since a fuel cell stack including a refrigerant channel formed between cell units each having an even number of electrolyte/electrode structures (MEA) and metal separators which are alternated does not have any structure supporting the separators forming the refrigerant channel in a stacking direction. In order to solve the above problem, in each of a first power generating unit and a second power generating unit, projections formed at the buffer portions of the separators are disposed in the same positions in the stacking direction with the MEA interposed therebetween. Since between the first and second power generating units, the projections of the buffer portions are staggered, the projections of the first and second power generating units are thereby disposed in the same positions in the stacking direction.

Abstract: A method of manufacturing a metal separator for a fuel cell includes providing an opening in a metal plate which is to be a part of the metal separator for the fuel cell, integrally molding a sealing member on both sides of an outer peripheral edge of the metal plate to cover the opening, and trimming the sealing member to remove a covering portion of the sealing member that covers the opening and to provide a fluid communication hole, at least one of a fuel gas, an oxidant gas, and a cooling medium being to pass through the fluid communication hole in the fuel cell.

Abstract: A fuel cell is formed by stacking first cell units and second cell units alternately. An inlet buffer and an outlet buffer are formed on a surface of a first metal separator of the first cell unit. Bosses are provided in the inlet buffer and the outlet buffer of the first metal separator. An inlet buffer and an outlet buffer are formed on a surface of the second metal separator of the first cell unit. Continuous guide ridges are formed in the inlet buffer and the outlet buffer of the second metal separator. The bosses and the continuous guide ridges are provided at positions overlapped with each other in the stacking direction.

Abstract: A fuel cell is formed by stacking a plurality of unit cells. Each of the unit cells includes a membrane electrode assembly, and an anode side metal separator and a cathode side metal separator sandwiching the membrane electrode assembly therebetween. In a surface of the cathode side metal separator, metal portions are exposed in at least part of a second flat portion in an area surrounded by seal lines SL of the anode side metal separator. Cutouts are formed on a surface of the cathode side metal separator by cutting at least part of the second flat portion up to the metal portions thereby to expose the metal portions through the cutouts.

Abstract: A fuel cell includes a membrane electrode assembly and a metal separator. The metal separator is stacked with the membrane electrode assembly. A reactant gas passage is provided between the membrane electrode assembly and the metal separator to supply a reactant gas along an electrode surface. The metal separator includes a reactant gas communication hole to communicate with the reactant gas passage. The metal separator further includes a plurality of groove groups each having a plurality of grooves press-formed to allow the reactant gas communication hole to communicate with the reactant gas passage. The grooves adjacent to each other are spaced apart by a first distance. The groove groups adjacent to each other are spaced apart by a second distance larger than the first distance.

Abstract: A cell unit of a fuel cell includes a second separator. A first oxygen-containing gas flow field is formed on a surface of the second separator. An inlet buffer is connected to an inlet of the oxygen-containing gas flow field, and an outlet buffer is connected to an outlet of the first oxygen-containing gas flow field. The inlet buffer includes a first inlet buffer area having a deep groove and a second inlet buffer area, and the outlet buffer includes a first outlet buffer area having a deep groove and a second outlet buffer area. The first inlet buffer area and the first outlet buffer area have different surface areas.

Abstract: A first metal separator of one of adjacent power generation cells and a second metal separator of the other of the adjacent power generation cells are directly stacked together to form a coolant flow field. The first metal separator has a press line protruding toward the coolant flow field, between a fuel gas flow field and an inlet buffer. The second metal separator has a press line protruding toward the coolant flow field, between an oxygen-containing gas flow field and an inlet buffer. The press lines contact each other to limit flow of the coolant into a back surface buffer.

Abstract: Auxiliary seals are provided on a surface of a first metal separator, between load receivers and an oxygen-containing gas supply passage, a fuel gas supply passage, an oxygen-containing gas discharge passage, and a fuel gas discharge passage, in relatively wide areas. The cross sectional shape of the auxiliary seal is the same as those of a flow field seal and ring-like seals, and the auxiliary seals are formed independently from the flow field seal and the ring-like seals.

Abstract: Each of the fuel cell units making up a fuel cell stack includes a first separator, a second separator, and a third separator. A predetermined number of load receivers are provided integrally on outer ends of the first separator, the second separator, and the third separator. The load receivers of the second separator protrude toward the casing beyond the other load receivers. Resin clips are inserted into the load receivers, such that the first separator, the second separator, and the third separator are fixed together by the resin clips.

Abstract: There has been a problem that the cell units cannot bear the load exerted on the units while being stacked since a fuel cell stack including a refrigerant channel formed between cell units each having an even number of electrolyte/electrode structures (MEA) and metal separators which are alternated does not have any structure supporting the separators forming the refrigerant channel in a stacking direction. In order to solve the above problem, in each of a first power generating unit and a second power generating unit, projections formed at the buffer portions of the separators are disposed in the same positions in the stacking direction with the MEA interposed therebetween. Since between the first and second power generating units, the projections of the buffer portions are staggered, the projections of the first and second power generating units are thereby disposed in the same positions in the stacking direction.

Abstract: A fuel cell is formed by sandwiching a membrane electrode assembly between a first separator and a second separator. The membrane electrode assembly includes a cathode, an anode, and a solid polymer electrolyte membrane interposed between the cathode and the anode. In the membrane electrode assembly, a catalyst area of an electrode catalyst layer of the cathode and an electrode catalyst layer of the anode terminates at a position spaced upwardly from lower ends of an oxygen-containing gas flow field and a fuel gas flow field.