A fuel cell stack structure in which unit cells are stacked includes first window frames and second window frame. The second window frames each have an area larger than an area of a first window frame and are periodically disposed at a predetermined interval in a direction in which the unit cells are stacked. Heat movement is promoted, a temperature deviation in the fuel cell stack structure is mitigated, and a temperature distribution is uniformized.

A fuel cell sub-assembly (100) comprising; a gasket (101) comprising a peripheral seal (102) for a fuel cell assembly, the peripheral seal defining a central aperture (103) of the gasket; a gas diffusion layer (104) for providing diffused gases to a proton exchange membrane (503) of a fuel cell, the gas diffusion layer (104) located within the central aperture; wherein at at least one convection point (105, 106), an inside facing surface (107) of the peripheral seal of the gasket is welded to a corresponding outward facing surface (108) of the gas diffusion layer (104).

A fuel cell sub-assembly (100) comprising; a gasket (101) comprising a peripheral seal (102) for a fuel cell assembly, the peripheral seal defining a central aperture (103) of the gasket; a gas diffusion layer (104) for providing diffused gases to a proton exchange membrane (503) of a fuel cell, the gas diffusion layer (104) located within the central aperture; wherein at at least one convection point (105, 106), an inside facing surface (107) of the peripheral seal of the gasket is welded to a corresponding outward facing surface (108) of the gas diffusion layer (104).

An electrode of an embodiment includes a catalyst layer having pores. A mode diameter of the pores is 10 μm or more and 100 μm or less. The catalyst layer may have a thickness of 0.05 μm or more and 3.0 μm or less. A value of the mode diameter of the pores may three times or more a value of a thickness of the catalyst layer.

An electrode of an embodiment includes a catalyst layer having pores. A mode diameter of the pores is 10 μm or more and 100 μm or less. The catalyst layer may have a thickness of 0.05 μm or more and 3.0 μm or less. A value of the mode diameter of the pores may three times or more a value of a thickness of the catalyst layer.

A hybrid bipolar plate assembly for a fuel cell includes a formed cathode half plate and a stamped metal anode half plate. The stamped metal anode half plate is nested with and affixed to the formed cathode half plate. Each of the half plates has a reactant side and a coolant side, a feed region, and a header with a plurality of header apertures. The coolant side of the formed cathode half plate has support features that can be different from and need not correspond with cathode flow channels formed on the opposite reactant side. The coolant side of the stamped metal anode half plate has lands corresponding with anode channels formed on the opposite oxidant side. The lands define a plurality of coolant channels on the coolant side of the stamped metal anode half plate and abut the coolant side of the formed cathode half plate.

A hybrid bipolar plate assembly for a fuel cell includes a formed cathode half plate and a stamped metal anode half plate. The stamped metal anode half plate is nested with and affixed to the formed cathode half plate. Each of the half plates has a reactant side and a coolant side, a feed region, and a header with a plurality of header apertures. The coolant side of the formed cathode half plate has support features that can be different from and need not correspond with cathode flow channels formed on the opposite reactant side. The coolant side of the stamped metal anode half plate has lands corresponding with anode channels formed on the opposite oxidant side. The lands define a plurality of coolant channels on the coolant side of the stamped metal anode half plate and abut the coolant side of the formed cathode half plate.

A cell unit CU includes a cell structure 1, a metal support plate 2 disposed on one side surface of the cell structure 1, and a frame 3 holding an outer peripheral part of the support plate 2. The cell structure 1 has a lamination of an anode electrode layer 4, an electrolyte layer 5, and a cathode electrode layer 6, in this order. The frame 3 includes a displacement guide 7 at least on one side surface of the frame 3. The displacement guide 7 has a coefficient of thermal expansion that is different from that of the frame 3 and is configured to make the frame 3 curve so that the cell structure 1 is concaved in accompany with thermal expansion. In the cell unit CU, a risk of concentration of tensile stress on the electrolyte layer 5 at the time of thermal expansion during operation is removed without reducing the strength of the frame 3, whereby occurrence of a crack and the like in the electrolyte layer 5 can be prevented beforehand.

A cell unit CU includes a cell structure 1, a metal support plate 2 disposed on one side surface of the cell structure 1, and a frame 3 holding an outer peripheral part of the support plate 2. The cell structure 1 has a lamination of an anode electrode layer 4, an electrolyte layer 5, and a cathode electrode layer 6, in this order. The frame 3 includes a displacement guide 7 at least on one side surface of the frame 3. The displacement guide 7 has a coefficient of thermal expansion that is different from that of the frame 3 and is configured to make the frame 3 curve so that the cell structure 1 is concaved in accompany with thermal expansion. In the cell unit CU, a risk of concentration of tensile stress on the electrolyte layer 5 at the time of thermal expansion during operation is removed without reducing the strength of the frame 3, whereby occurrence of a crack and the like in the electrolyte layer 5 can be prevented beforehand.

A fuel cell stack includes a stack body of power generation cells stacked in a horizontal direction. An oxygen-containing gas flow field is formed in the fuel cell stack, for allowing an oxygen-containing gas to flow along an electrode surface of a membrane electrode assembly. A plurality of oxygen-containing gas discharge passages for discharging the oxygen-containing gas as a reactant gas pass through the fuel cell stack in a stacking direction of the power generation cells. Each of the oxygen-containing gas discharge passages is connected to an outlet. The plurality of oxygen-containing gas discharge passages are connected together by a first connection channel at an end opposite to the outlet.