Abstract: Provided is a fuel cell system which is capable of suppressing deterioration in the performance and durability of a fuel cell stack or restoring deterioration in performance of the fuel cell stack. In addition, provided is a method of operating the fuel cell system. The fuel cell system includes a fuel cell stack in which a gas passage for an anode and a cathode and a heat transmission medium passage have a structure in which inlet-side regions of each of the passages substantially overlap with each other. Outlet-side regions of the anode gas passage, the cathode gas passage, and the heat transmission medium passage substantially overlap with each other as viewed from a direction in which the unit cells are stacked. The fuel cell system also includes at least one anode gas flow inverting device and a cathode gas flow inverting device.

Abstract: Provided is a method of preserving a PEFC stack, which is capable of controlling degradation of performance of the PEFC stack during a time period that elapses from when the stack is placed in an uninstalled state until it is placed in an installation position and is practically used. Provided is a preservation assembly of the PEFC stack which is capable of sufficiently inhibiting degradation of performance of the PEFC stack particularly during a time period that elapses from when the stack is placed in the uninstalled state until it is placed in the installation position and is practically used.

Abstract: Even if reaction gas flows into a substantially rectangular anode-side and cathode-side gaps formed between an annular main body portion and a membrane electrode assembly in an anode side and a cathode side of a fuel cell, the reaction gas is prevented from flowing out from an outlet without passing through an electrode to cause degradation of power generation efficiency. At least one of anode-side gasket and cathode-side gasket in the fuel cell is provided with an extra sealing portion connected to an annular main body portion in such a manner that, among two pairs of gap portions opposing to each other in the anode-side gap and the cathode-side gap, the extra sealing portion intersects with one pair of gap portions having a larger pressure gradient of fuel gas and oxidant gas in a direction from an upstream side to a downstream side of a fuel gas flow channel and an oxidant gas flow channel.

Abstract: A fuel cell comprising: a membrane electrolyte assembly having a polymer electrolyte membrane and a pair of catalyst electrodes, namely an air electrode and a fuel electrode sandwiching the polymer electrolyte membrane; a pair of separators, namely an air electrode separator and a fuel electrode separator sandwiching the membrane electrolyte assembly; two or more oxidizing gas channels running in a certain direction for the purpose of supplying an oxidizing gas to the air electrode; and two or more linear fuel gas channels arranged parallel to the certain direction for the purpose of supplying a fuel gas to the fuel electrode. Large gaps and small gaps are provided alternately between adjacent two oxidizing gas channels along the certain direction, and the fuel gas channels do not overlap portions of the oxidizing gas channels, that are parallel to the fuel gas channels.

Abstract: A preservation assembly of a polymer electrolyte fuel cell stack is provided. The assembly includes an uninstalled polymer electrolyte fuel cell stack and sealing units. The uninstalled polymer electrolyte fuel cell stack is provided with an oxidizing agent passage having an inlet and an outlet and extending through a cathode and a reducing agent passage having an inlet and an outlet and extending through an anode. The sealing units include sealing plugs or containers and are configured to seal the inlet and the outlet of the oxidizing agent passage within which an oxygen concentration has been decreased and to seal the inlet and the outlet of the reducing agent passage within which the oxygen concentration has been decreased. The uninstalled polymer electrolyte fuel cell stack is in a state before an assembled polymer electrolyte fuel cell stack is incorporated into a fuel cell system.

Abstract: The durability of a polymer electrolyte fuel cell is very significantly improved by using a tightening pressure of about 2 to 4 kgf/cm2 of area of electrode; or a tightening pressure of about 4 to 8 kgf/cm2 of contact area between electrode and separator plate; or by selecting a value not exceeding about 1.5 mS/cm2 for the short-circuit conductivity attributed to the DC resistance component in each unit cell; or by selecting a value not exceeding about 3 mA/cm2 for the hydrogen leak current per area of electrode of each MEA. Further, in a method of manufacturing or an inspection method for a polymer electrolyte fuel cell stack, fuel cells having high durability can be efficiently manufactured by removing such MEAs or unit cells using such MEAs or such cell stacks having short-circuit conductivity values and/or hydrogen leak current values exceeding predetermined values, respectively.

Abstract: A fuel cell comprising: a membrane electrolyte assembly having a polymer electrolyte membrane and a pair of catalyst electrodes, namely an air electrode and a fuel electrode sandwiching the polymer electrolyte membrane; a pair of separators, namely an air electrode separator and a fuel electrode separator sandwiching the membrane electrolyte assembly; two or more oxidizing gas channels running in a certain direction for the purpose of supplying an oxidizing gas to the air electrode; and two or more linear fuel gas channels arranged parallel to the certain direction for the purpose of supplying a fuel gas to the fuel electrode. Large gaps and small gaps are provided alternately between adjacent two oxidizing gas channels along the certain direction, and the fuel gas channels do not overlap portions of the oxidizing gas channels, that are parallel to the fuel gas channels.

Abstract: Provided is a method of preserving a PEFC stack, which is capable of controlling degradation of performance of the PEFC stack during a time period that elapses from when the stack is placed in an uninstalled state until it is placed in an installation position and is practically used. Provided is a preservation assembly of the PEFC stack which is capable of sufficiently inhibiting degradation of performance of the PEFC stack particularly during a time period that elapses from when the stack is placed in the uninstalled state until it is placed in the installation position and is practically used.

Abstract: A method of preserving a PEFC stack of the present invention is a method of preserving a PEFC stack that is provided with an oxidizing agent passage having an inlet and an outlet and extending through a cathode and a reducing agent passage having an inlet and an outlet and extending through an anode. The method comprises preserving the polymer electrolyte fuel cell stack in an uninstalled state under a condition in which an oxygen concentration within the oxidizing agent passage and within the reducing agent passage is lower than an oxygen concentration in atmospheric air.

Abstract: Provided is a method of preserving a PEFC stack, which is capable of controlling degradation of performance of the PEFC stack during a time period that elapses from when the stack is placed in an uninstalled state until it is placed in an installation position and is practically used. Provided is a preservation assembly of the PEFC stack which is capable of sufficiently inhibiting degradation of performance of the PEFC stack particularly during a time period that elapses from when the stack is placed in the uninstalled state until it is placed in the installation position and is practically used.

Abstract: A polymer electrolyte fuel cell of the present invention includes a membrane electrode assembly (5) having a pair of electrodes (4a, 4b) sandwiching a portion of a polymer electrolyte membrane (1) which is inward relative to a peripheral portion thereof, a first separator (6a), and a second separator (6b), the first separator (6a) is provided with a first reaction gas channel (8) on one main surface, the second separator (6b) is provided with a second reaction gas channel (9) on one main surface such that the second reaction gas channel (9) has a second rib portion (12), the first reaction gas channel (8) is formed such that a ratio of a first reaction gas channel width of an upstream portion (18b) to the second rib portion (12) is set larger than a ratio of a first reaction gas channel width of a downstream portion (18c) to the second rib portion (12), and the ratio of the first reaction gas channel width of the upstream portion (18b) to the second rib portion (12) is a predetermined ratio.

Abstract: A fuel cell separator of the present invention is a plate-shaped fuel cell separator including a reaction gas supply manifold hole 21, a reactant gas discharge manifold hole 22, a groove-shaped first reactant gas channel 131, and one or more groove-shaped second reaction gas channels 132 and 133, wherein the first reactant gas channel 131 includes a first portion 41 and a second portion 51 located upstream of the first portion 41, and a cross-sectional area of a first specified portion 81 which is a continuous portion including at least the first portion of the first reactant gas channel 131 and/or a cross-sectional area of a second specified portion 82 which extends continuously from at least a downstream end of the first reactant gas channel 131 is/are smaller than cross-sectional areas of the second reactant gas channels 132 and 133.

Abstract: A preservation assembly of a polymer electrolyte fuel cell stack is provided. The assembly includes an uninstalled polymer electrolyte fuel cell stack and sealing units. The uninstalled polymer electrolyte fuel cell stack is provided with an oxidizing agent passage having an inlet and an outlet and extending through a cathode and a reducing agent passage having an inlet and an outlet and extending through an anode. The sealing units include sealing plugs or containers and are configured to seal the inlet and the outlet of the oxidizing agent passage within which an oxygen concentration has been decreased and to seal the inlet and the outlet of the reducing agent passage within which the oxygen concentration has been decreased. The uninstalled polymer electrolyte fuel cell stack is in a state before an assembled polymer electrolyte fuel cell stack is incorporated into a fuel cell system.

Abstract: A polymer electrolyte fuel cell system of the present invention comprises cells 10, a stack 100, a temperature control device (160, 140, 40, 41), an anode gas supplier 110, a cathode gas supplier 120, and a controller 300. When a power generation output of the stack 100 is reduced, the controller 300 controls the anode gas supplier 110 and the cathode gas supplier 120 to reduce a supply amount of the anode gas and a supply amount of the cathode gas, and controls at least one of the anode gas supplier 110, the cathode gas supplier 120, and the temperature control device 100 to cause a dew point temperature of a gas supplied to at least one of the anode gas channels and the cathode gas channels to be higher relative the temperature of the stack 100 so that the gas becomes supersaturated or more supersaturated than prior to causing the dew point temperature of the gas to be higher.

Abstract: Disclosed is a fuel cell including: a membrane electrolyte assembly which includes a polymer electrolyte membrane and a pair of catalyst electrodes between which the polymer electrolyte membrane is held; and separators A and B between which the membrane electrolyte assembly is held, wherein the separator A includes first gas flow channels a1 and second gas flow channels a2 which are placed adjacent to the first gas flow channels al, the first and second gas flow channels a1 and a2 supplying an oxidizing gas or a fuel gas to the membrane electrolyte assembly, the first and second gas flow channels a1 and a2 run in parallel to each other and are alternately arranged, the first gas flow channels a1 are larger in cross sectional area than the second gas flow channels a2; wherein the separator B includes first gas flow channels b1 which run in parallel to the first and second gas flow channels a1 and a2, and second gas flow channels b2 which are placed adjacent to the first gas flow channels b1, the first and seco

Abstract: A separator for use in a fuel cell of the present disclosure includes: a plate; a first gas manifold hole (51) for supplying a reactant gas, formed to penetrate said plate in a thickness direction thereof; a second gas manifold hole (52) for discharging the reactant gas, formed to penetrate said plate in a thickness direction thereof; one or more groove-like first main gas channels (18) formed on a surface of said plate to have one end connected to said first gas manifold hole (51) and the other end connected to said second gas manifold hole; a groove-like first sub-gas channel (28) formed on the surface of said plate to have one end connected to at least one of said first gas manifold hole (51) and said second gas manifold hole (52); and a groove-like second sub-gas channel (38) formed on the surface of said plate to have one end branching from said first sub-gas channel (28) and the other end being closed.

Abstract: Provided is a fuel cell system which is capable of well preventing deterioration of performance of a fuel cell stack or well restoring deteriorated performance of the fuel cell stack and of suppressing deterioration of durability of the fuel cell stack, and a method of operating the fuel cell system.

Abstract: The invention provides a fuel cell separator wherein a first reaction gas channel 131 has a first portion 41 and a second portion 51 located upstream of the first portion 41, the first portion 41 lying closest to the upstream end of the first reaction gas channel 131 among portions located between the second portion 51 and the downstream end of the first reaction gas channel 131, the second portion 51 lying closest to the downstream end among portions located between the upstream end and the first portion 41 of the first reaction gas channel 131. Second reaction gas channels 132, 133 do not exist between the first portion 41 and the upstream end but exist between the second portion 51 and the downstream end. The first reaction gas channel 131 is communicated with at least one (hereinafter referred to as the “specific channel”) of the second reaction gas channels 132, 133 in a portion (hereinafter referred to as the “specific portion”) between the first portion 41 and the downstream end.

Abstract: A polymer electrolyte fuel cell includes: a membrane-electrode assembly (10) having a polymer electrolyte membrane (1) and a pair of electrodes (4, 8) sandwiching a portion of the polymer electrolyte membrane (1) which portion is located inwardly of a peripheral portion of the polymer electrolyte membrane (1); an electrically-conductive first separator (30) disposed to contact the membrane-electrode assembly (10) and formed such that a groove-like first reactant gas channel (37) is formed on one main surface thereof so as to bend; and an electrically-conductive second separator (20) disposed to contact the membrane-electrode assembly (10) and formed such that a groove-like second reactant gas channel (27) is formed on one main surface thereof so as to bend, wherein the first reactant gas channel (27) is formed such that a width of a portion of the first reactant gas channel (27) which portion is formed at least a portion (hereinafter referred to as an uppermost stream portion 8C of the first separator 30) loc

Abstract: A polymer electrolyte fuel cell is provided with a conductive separator having one or more gas flow channels for supplying and exhausting a gas to and from an electrode of the fuel cell. The gas flow channels are connected to and in fluid communication with an inlet manifold on the separator. The cell also includes a gas supply connection in fluid communication with the inlet manifold of the separator. Water accumulation in the cell can be advantageously reduced by configuring the connections to the inlet manifold so that the lowermost part of any gas flow channel connections with the inlet manifold is above the uppermost part of the gas supply connection to the inlet manifold.