Abstract: A fuel cell stack comprising multiple arrays of one or more fuel cells, each comprising an electrolyte layer, an anode layer and a cathode layer; gas separator plates between adjacent fuel cells; and oxidant gas distribution passages and fuel gas distribution passages between adjacent fuel cells; and gas separators opening to the cathode layers and the anode layers, respectively, of the fuel cells. The fuel cell arrays comprise at least first stage fuel cell arrays having associated first fuel gas distribution passages to receive fuel gas from one or more fuel gas supply manifolds and second stage fuel cell arrays having associated second fuel gas distribution passages which receive fuel exhaust from the fuel cells of the first stage fuel cell arrays. The second stage fuel cell arrays are interleaved in the stack between first stage fuel cell arrays to improve thermal gradients. Other interleaving arrangements are possible.

Abstract: Collector plates made of bulk-solidifying amorphous alloys, the bulk-solidifying amorphous alloys providing ruggedness, lightweight structure, excellent resistance to chemical and environmental effects, and low-cost manufacturing, and methods of making such collector plates from such bulk-solidifying amorphous alloys are provided.

Abstract: An interconnect for a fuel cell stack includes a first set of gas flow channels in a first portion of the interconnect, and a second set of gas flow channels in second portion of the interconnect. The channels of the first set have a larger cross sectional area than the channels of the second set.

Abstract: A fuel cell assembly is disclosed that utilizes a water transport structure extending from fuel cell plates of the assembly into fuel cell assembly manifolds, wherein the water transport structure facilitates the transport of liquid water from the fuel cell plates thereby minimizing the accumulation of liquid water and ice in the fuel cell stack.

Abstract: A cell stack comprising an electrochemical cell, or a plurality of axially arranged electrochemical cells, with an end plate at each end of the stack, each cell comprising an active area surrounded by a peripheral area, wherein the active area comprises the membrane electrode assembly, and the peripheral area includes one or more channels for reactants, and wherein the stack comprises means for applying pressure axially to the active area to contact the membrane and electrodes, and separate means for applying pressure axially to the peripheral area. Further, a method of performing an electrochemical reaction in a cell comprising an active area surrounded by a peripheral area, comprises applying pressure to the active area, and varying the pressure during operation of the cell, wherein the active area includes the membrane electrode assembly and is the area where the cell reaction occurs.

Abstract: A fuel cell system with reduced volume through decreasing the thickness of a stack comprises: a stack which comprises a plurality of membrane electrode assemblies stacked so that the cathode electrodes face each other and the anode electrodes face each other, and separators that are interposed between the membrane electrode assemblies, and which have a flow path passing through from a first face to a second face on a region corresponding to a region where each cathode electrode or anode electrode is formed.

Abstract: Fuel cells and related assemblies involving directionally independent channels are provided. In this regard, a representative fuel cell stack (100) includes: a first fuel cell (102) having channels (116, 216, 316; 156, 256, 356) associated with an anode; and a second fuel cell (101), located adjacent the first fuel cell, having channels (128, 228, 328; 158, 258, 358) associated with a cathode, the channels associated with the cathode exhibiting directional independence (344) with respect to the channels associated with the anode. A ribbed, three plate (111, 211, 311; 121, 221, 321; 150, 250, 350), assembly (152, 252) may provide fuel reactant and anode coolant flow channels having a first parallel orientation (342) and oxidant reactant and cathode coolant flow channels having a second parallel orientation independent of and different (344) than the first orientation.

Abstract: A fuel cell stack configured to alleviate pressure and decrease the flow rate of at least one of a fuel and an oxidant is disclosed. The fuel cell stack includes a membrane-electrode assembly, an anode separator, a cathode separator and a filing member. The membrane-electrode assembly may include an electrolyte membrane, an anode formed on a first surface of the electrolyte membrane, and a cathode formed on a second surface of the electrolyte membrane. The anode separator may include a fuel channel, a fuel inlet manifold in fluid communication with the fuel channel, and a fuel outlet manifold in fluid communication with the fuel channel. The cathode separator may include an oxidant channel, an oxidant inlet manifold in fluid communication with the oxidant channel, and an oxidant outlet manifold in fluid communication with the oxidant channel. The filling member may be positioned within at least one of the fuel inlet manifold and the oxidant inlet manifold.

Abstract: A fuel cell assembly and method of forming the same is disclosed, the fuel cell assembly including a membrane electrode assembly, a plurality of diffusion media, and a plurality of bipolar plates, wherein the diffusion media are adhered to the bipolar plates with an adhesive layer adapted to minimize an electrical resistance within the fuel cell assembly.

Abstract: A process for molding a composite unipolar plate for a fuel cell stack that increases the strength of a header region of the plate. High strength, non-conductive prepeg inserts are positioned within the mold that are shaped to the configuration of the header region, including the openings that define the various inlet and outlet manifolds. A bulk molding compound charge is positioned in the mold and pressed under high heat so that the bulk molding compound disperses in the mold, and covers the prepeg inserts so that the prepeg inserts are cured to the bulk molding compound.

Abstract: A fuel cell system that employs a surface active agent that reduces the surface tension of the water in the flow field channels. The fuel cell system includes humidifiers that humidify the cathode inlet airflow and the hydrogen anode gas. The surface active agent is mixed with the humidifying water in the humidifiers so that the surface active agent enters the flow field channels to reduce the surface tension of the water therein, thus allowing the water to wick the channels. In one non-limiting embodiment, the surface active agent is ethanol. Ruthenium can be added to the platinum in the catalyst layers of the fuel cells to mitigate the poisoning of platinum by carbon monoxide, which is one of the oxidation products of ethanol on the cathode side of the fuel cell.

Abstract: Collector plates made of bulk-solidifying amorphous alloys, the bulk-solidifying amorphous alloys providing ruggedness, lightweight structure, excellent resistance to chemical and environmental effects, and low-cost manufacturing, and methods of making such collector plates from such bulk-solidifying amorphous alloys are provided.

Abstract: A fuel cell includes a membrane electrode assembly (MEA), a fuel delivery system distributing fuel to an anode side of the MEA, and a flow distributor delivering an oxidizer to a cathode side of the MEA. The flow distributor includes at least one serpentine channel through which the oxidizer is delivered to the cathode side of the MEA. Each portion of the serpentine channel delivers oxidizer to a portion of the cathode side of the MEA in contact, directly or through a porous diffuser, with the channel portion. The channel portion transfers water with the portion of the MEA in contact with the channel portion and also transfers water between adjacent channel portions via a water-permeable, gas impermeable material that defines at least a portion of the channel.

Abstract: The present invention relates to a sealing structure for polymer electrolyte fuel cell, which comprises a bipolar plate with sealing groove to be filled with rubber using a dispenser, and a gasket interposed between the bipolar plate and a membrane electrode assembly. That is, according to the present invention, the thickness deviation in a gasket can be softened by interposing a gasket between a rubber ands a membrane electrode assembly after filling rubber in a sealing groove formed on a bipolar plate using a dispenser. Also, nonuniform stress distribution can be resolved because a gasket covers with a pressure despite the height deviation of rubber, and a stress is not directly transmitted to a membrane electrode assembly and dispersed by a gasket despite nonuniform stress distribution.

Abstract: Flow field plate constructions for bipolar plates are disclosed for use in fuel cell stacks that are subject to freezing temperatures. In designs having internal coolant flow fields and reactant backfeed ports, relief ducts are provided in the supporting walls surrounding the backfeed ports in order to allow for ice formation and thus prevent cracking of the plates.

Abstract: A metal halogen electrochemical energy cell system that generates an electrical potential. One embodiment of the system includes at least one cell including at least one positive electrode and at least one negative electrode, at least one electrolyte, a mixing venturi that mixes the electrolyte with a halogen reactant, and a circulation pump that conveys the electrolyte mixed with the halogen reactant through the positive electrode and across the metal electrode. Preferably, the positive electrode comprises porous carbonaceous material, the negative electrode comprises zinc, the metal comprises zinc, the halogen comprises chlorine, the electrolyte comprises an aqueous zinc-chloride electrolyte, and the halogen reactant comprises a chlorine reactant. Also, variations of the system and a method of operation for the systems.

Abstract: A coolant supply passage, a coolant discharge passage, and an air-releasing passage extend through first and second metal plates of a metal separator in a stacking direction of the first and second metal plates. The coolant supply passage and the coolant discharge passage are provided at vertically middle positions of opposite horizontal ends of the separator. A coolant flow field is connected between the coolant supply passage and the coolant discharge passage. The air-releasing passage for releasing air from the coolant flow field is formed above the coolant discharge passage. At least part of the air-releasing passage is positioned above the top of the coolant flow field.

Abstract: An oxygen-containing gas flow field is formed on a surface of a cathode side metal separator of a fuel cell. The oxygen-containing gas flow field is connected between an oxygen-containing gas supply passage and an oxygen-containing gas discharge passage. A coolant flow field is formed on the other surface of the cathode side metal separator, on the back of the oxygen-containing gas flow field. The cathode side metal separator has linear guide ridges protruding from an intermediate height area toward the oxygen-containing gas flow field to form a continuous guide flow field, and bosses protruding from the intermediate height area toward the coolant flow field to form an embossed flow field.

Abstract: A channel plate assembly of a stack for a fuel cell and a method of manufacturing the channel plate assembly. The channel plate assembly of a stack for a fuel cell includes a bridge piece disposed on a channel plate to entirely surround a manifold, and a gasket disposed on the channel plate to cover the bridge piece, wherein the channel plate assembly is manufactured in an integrated fashion.

Abstract: A seal structure is disclosed for forming a substantially fluid tight seal between a UEA and a plate of a fuel cell system, the seal structure including a sealing member formed in one fuel cell plate, a seal support adapted to span feed area channels in an adjacent fuel cell plate, and a seal adapted to cooperate with a UEA disposed between the fuel cell plates, the sealing member, and the seal support to form a substantially fluid tight seal between the UEA and the one fuel cell plate. The seal structure militates against a leakage of fluids from the fuel cell system, facilitates the maintenance of a velocity of a reactant flow in the fuel cell system, and a cost thereof is minimized.

Abstract: A fuel cell assembly is disclosed that utilizes a water transport structure extending from fuel cell plates of the assembly into fuel cell assembly manifolds, wherein the water transport structure facilitates the transport of liquid water from the fuel cell plates thereby minimizing the accumulation of liquid water and ice in the fuel cell stack.

Abstract: An electricity generator includes a membrane electrode assembly; a separator coupled to the membrane electrode assembly and including a first region and a second region; and a thermal conductor on one of the first region and the second region.

Abstract: A bipolar plate assembly is described. The coolant passage on either the anode side or the cathode side includes a material having a low thermal conductivity. Fuel cells containing the bipolar plate assembly and methods of making the bipolar plate assembly are also described.

Abstract: A flow field plate or bipolar plate for a fuel cell that includes a conductive coating having formed nanopores that make the coating hydrophilic. Any suitable process can be used to form the nanopores in the coating. One process includes co-depositing a conductive material and a relatively unstable element on the plate, and then subsequently dissolving the element to remove it from the coating and create the nanopores. Another process includes using low energy ion beams for ion beam lithography to make the nanopores.

Abstract: A fuel cell includes at least one fuel cell element, which includes an anode, a cathode, a proton exchange membrane sandwiched between the anode and the cathode, a first flow guide plate, and a second flow guide plate. Each of the anode and the cathode includes a catalyst layer including a number of tube carriers having electron conductibility, a number of catalyst particles uniformly adsorbed on an inner wall of each of the tube carriers, and a proton conductor filled in each of the plurality of tube carriers. A first end of each of the tube carriers connects with the proton exchange membrane. The first flow guide plate is disposed on a surface of the anode away from the proton exchange membrane. The second flow guide plate is disposed on a surface of the cathode away from the proton exchange membrane.

Abstract: The invention relates to a contact arrangement for a fuel cell stack, especially for an SOFC fuel cell stack, comprising an interconnector arrangement which is arranged to establish an electrically conducting connection via at least one contact element on the anode side and at least one such element on the cathode side between an anode of a first membrane electrode assembly and a cathode of a second membrane electrode assembly. The invention is characterized in that at least one component to be sintered is provided on only one side of the interconnector arrangement, on the side of the interconnector arrangement facing the anode or the one facing the cathode, the component being coupled to the first or second membrane electrode assembly in such a manner that the electrically conducting connection can be established via the contact element on the anode side or via that on the cathode side by sintering the component to be sintered.

Abstract: A fuel cell separator plate having a planar substrate having a main body with first and second opposed major surfaces, a first open channel reactant flow field recessed in the first major surface, and a first segment extending from the main body, and a thermally and electrically conductive first current collector layer having a flow field portion on the first major surface of the main body and a heat exchange portion extending from the flow field portion onto the first segment such that heat in the flow field portion conducts to the heat exchange portion during fuel cell use.

Abstract: A fuel cell having a pair of bipolar plates is provided. Each of the bipolar plates has a nested active area and a non-nested feed area which also may serve as active area. An electrolyte membrane is disposed between a pair of electrodes and a pair of diffusion medium layers. Each of the diffusion medium layers is disposed adjacent the nested active areas and non-nested feed areas of the bipolar plates. A porous, electrically conductive spacer is disposed between one of the diffusion medium layers and one of the bipolar plates. A fuel cell stack having the fuel cell is also provided.

Abstract: Provided is a fuel battery including: a fuel battery cell assembly having at least two fuel battery cells coplanarly disposed, the fuel battery cell including a membrane electrode assembly having an anode, an electrolytic membrane, and a cathode stacked on one another in this order, and a flow channel plate provided on an anode side and having on an anode-side surface thereof an in-cell fuel flow channel through which liquid fuel flows; and a fuel distributor having an out-cell fuel flow channel connected to each of the in-cell fuel flow channels to distribute the liquid fuel to the fuel battery cells.

Abstract: A fuel cell comprising anode and cathode flow field plates having a multitude of flow channels separated by land features wherein the land features of the anode side are wider than the land features of the cathode side is disclosed. In fuel cells, the flow field plate arrangement of the present invention provides higher power (lower cost per kW), improved durability, and less stringent assembly alignment.

Abstract: A separator unit inserted into a fuel cell having an electrolyte layer interposed between a fuel electrode and an oxygen electrode is provided with a plate like separator that separates fuel gas supplied to the fuel electrode from oxidizing gas supplied to the oxygen electrode, and a mesh like collector having an opening that forms one of a passage through which the fuel gas flows and a passage through which the oxidizing gas flows. The collector is provided to at least one side of the separator base in abutment against one of the fuel electrode and the oxygen electrode. The separator base has a coolant passage formed therein, through which a coolant is allowed to flow, and an electrode abutment portion of the collector, which abuts against one of the fuel electrode and the oxygen electrode, has an aperture ratio higher than those of other portions of the collector.

Abstract: A fuel cell with multiple independent reaction regions comprises multiple fuel cell units. Each fuel cell unit comprises bipolar plates and a membrane electrode assembly located between the bipolar plates. The membrane electrode assembly comprises a proton exchange membrane and catalyst layers located at both sides of the proton exchange membrane, and the catalyst layers at least at one side of the proton exchange membrane are formed with multiple mutually independent catalyst sublayers. Different from the prior design concepts of striving to distribute reactants as uniformly as possible in the whole reaction area, the whole cell in this invention is divided into multiple independent reaction regions, and relevance of the reaction regions is eliminated. Therefore, by partitioning and reducing the amplitude of possible voltage difference, this invention is able to reduce electrochemical corrosion and maximize performance of each independent region and the whole fuel cell.

Abstract: The invention relates to a fuel cell, having a first electrode, a second electrode, and a membrane element, in which the membrane element is disposed between the first electrode and the second electrode. At least one of the electrodes has a flow field plate and at least one flow conduit, through which a reactant can be conducted, extends in at least one outer surface of the flow field plate. According to the invention, it is provided that the flow field plate has at least one microreaction chamber, and the microreaction chamber is disposed in the outer surface and on the flow conduit. A catalyst is disposed on at least a part of the microreaction chamber in such a way that the catalyst has contact simultaneously with the membrane element and the inflowing reactant.

Abstract: A multi-layer diffusion medium substrate having improved mechanical properties is disclosed. The diffusion medium substrate includes at least one stiff layer and at least one compressible layer. The at least one stiff layer has a greater stiffness in the x-y direction as compared to the at least one compressible layer. The at least one compressible layer has a greater compressibility in the z direction. A method of fabricating a multi-layer diffusion medium substrate is also disclosed.

Abstract: Disclosed is a direct oxidation fuel cell including at least one cell, each cell comprising a stack of: a membrane electrode assembly including an anode, a cathode, and an electrolyte membrane interposed between the anode and the cathode; an anode-side separator facing the anode; and a cathode-side separator facing the cathode. The anode-side separator has a serpentine fuel flow channel on a surface thereof facing the anode, a fuel is supplied from upstream of the fuel flow channel, and the serpentine fuel flow channel has a cross-sectional area that increases stepwise from upstream toward downstream of the fuel flow channel.

Abstract: A method of coating a surface of a fuel cell plate is disclosed herein, and involves forming a sol gel mixture by mixing a weak acid and a composition including at least two metal oxide precursors. One of the metal oxide precursors is configured to be hydrolyzed by the weak acid to form a mixed metal oxide framework with an other of the metal oxide precursors having at least one organic functional group that is not hydrolyzed by the weak acid. The mixture is applied to the surface, and is condensed by exposure to air at least one predetermined temperature and for a predetermined time. The sol gel mixture is immersed in water at a predetermined temperature and for a predetermined time to form a porous, hydrophilic, and conductive film on the surface.

Abstract: A fuel cell with a gas chamber, arranged between two plate elements, is provided. One of the plate elements includes bosses for supporting the plate element on the other plate element in a regular grid structure. Between the bosses runs a network of gas channels passing through the gas chamber, the bosses being at most three times longer than wide. The bosses form between themselves first gas channels in a first region of the gas chamber and larger-volume second gas channels in a second region of the gas chamber.

Abstract: A microfluidic system through which a solution of at least an oxidable compound is fed to a feed manifold of an energy converting electrochemical device includes a flow connector. The flow connector includes a silicon platform having a bottom side and an opposing top side, and through holes extending therethough. The silicon platform includes first and second channels defined on the bottom side for communicating with the through holes. The second channel forms an inlet for the feed manifold of the energy converting electrochemical device when the bottom side of the silicon platform is coupled to a flat coupling area of the device. A micropump module is coupled to the top side of the silicon platform for communicating with the through holes in the first and second channels. First and second supply cartridges are coupled to the top side of the silicon platform for communicating with the through holes in the first channel.

Abstract: The present invention is a solid oxide fuel cell configuration which equalizes gas volume distributed into each power generation cell to stabilize fuel cell output and improve the output efficiency. In the present invention, a flat plate laminating type solid oxide fuel cell has a reactant gas supply manifold extending through a fuel cell stack in the laminating direction, for supplying reactant gas to each of power generation cells through gas passages of separators which are communicated with the manifold. The manifold and the passages of the separators are in communication with each other through a gas-flow throttle mechanisms.

Abstract: There is provided a separator for a fuel cell having a very good anticorrosiveness and electrical conductivity. A separator for a fuel cell according to the present invention includes: a base 1 formed of a steel which contains 10.5 mass % or more of Cr; a metal film 3 formed on the surface of the base 1; and an intermediate layer 2 formed between the base 1 and the metal film 3, the intermediate layer 2 containing oxygen. The metal film 3 is composed of at least one metallic element selected from the group consisting of Ta, Nb, and Ti, and the intermediate layer 2 contains Fe and Cr which are contained in the steel and at least one metallic element selected from the group consisting of Ta, Nb, and Ti composing the metal film 3.

Abstract: In a proton exchange membrane fuel cell power plant (9) in which each fuel cell (11) employs reactant gas flow field channels (51) extending inwardly from a surface of a conductive, hydrophilic reactant gas flow field plate (50), for at least one of the reactants of the fuel cell, a region (63) of the reactant gas flow field channels is substantially shallower than the remaining portion (60) of the flow field channels thereby decreasing resistance to a gas phase mass transfer from the wetted walls of the flow field plate to the gas in the region (63); the resulting increase in thickness of the web (58) adjacent the region (63) reduces the resistance to liquid water transport from the first coolant channel (52) to the inlet edge (55) of the plate (50) providing a higher evaporation rate into the reactant gas in the shallow region (63).

Abstract: In a fuel cell, an elastic body provides first protrusion T10 that encompasses the perimeter of the passage hole at plate member 40 and the leading edge of which spans the entire region and tightly adheres to plate member 40, provides second protrusion S20 that is disposed within the placement region of reaction membrane 10 so as to encompass the perimeter of the gas diffusion layer, and provides third protrusion S30 that is disposed to encompass the region at which first protrusion T10 is disposed and the region at which second protrusion S20 is disposed, and is disposed outside the placement region for the reaction membrane, and the leading edge of which spans the entire region and tightly adheres to a separator 30.

Abstract: A bipolar plate and regenerative fuel cell stacks including the bipolar plates and membrane electrode assemblies (MEAs) alternately stacked. The bipolar plate comprises a plate main body formed of an electrically conductive material. The plate main body has a first surface and a second surface opposite the first surface. Each surface has reaction flow channels through which fluids pass. The reaction flow channels on the first surface have a plurality of ribs therebetween forming an interdigitate flow field pattern. The reaction flow channels on the second surface have a plurality of ribs therebetween forming an interdigitate flow field pattern or a flow field pattern different from an interdigitate flow field pattern, e.g., a serpentine flow field pattern.

Abstract: A bipolar separator assembly for use with a fuel cell comprising: a plate member having opposing first and second surfaces compatible with fuel gas and oxidant gas, respectively, the plate member having first and second opposing end segments and third and fourth opposing end segments which are transverse to the first and second opposing end segments; first and second pocket members situated adjacent the first and second end segments and extending outward of the first surface, the first and second pocket members being adapted to enclose opposing ends of an anode current collector, and third and fourth pocket members situated adjacent the third and fourth end segments and extending outward of the second surface, the third and fourth pocket members being adapted to enclose opposing ends of a cathode current collector, wherein at least a portion of each of the first, second, third and fourth pocket members is formed separately from the plate member and is releasably positioned relative to the plate member.

Abstract: A fuel cell comprising a membrane-electrode assembly having an anode electrode face; an anode plate adjacent said membrane-electrode assembly electrode face and coupled thereto by a sealing gasket. The sealing gasket, electrode face and anode plate together define a fluid containment volume for delivery of anode fluid to the electrode face. A sheet of porous diffuser material is situated in the fluid containment volume and having at least one plenum defined between at least one lateral edge of the sheet of diffuser material and the sealing gasket. Fluid for delivery to an active surface of the membrane-electrode assembly may be delivered by the plenum and by diffusion through the diffuser material to such an extent that fluid flow channels in the anode plate are not required.

Abstract: A separator includes a first fuel gas supply unit, a second fuel gas supply unit, first sandwiching sections, second sandwiching sections, a first case unit and a second case unit. The first and second sandwiching sections are connected to the first fuel gas supply unit and the second fuel gas supply unit, respectively, through first bridges. The first case unit and the second case unit are connected to the first sandwiching sections and the second sandwiching sections through second bridges. A first surface pressure F1 generated near a fuel gas supply passage, a second surface pressure F2 generated near an oxygen-containing gas supply passage, and a third surface pressure F3 generated near electrolyte electrode assemblies have different values.

Abstract: A fuel cell separator capable of improving stack performance by reducing the deviation in cell performance and diminishing dead space, and a fuel cell stack using the same are disclosed. The fuel cell separator may include a base member, a first channel group disposed on a surface of the base member and a second channel group disposed on the surface of the base member. The first channel group may include at least one channel and the second channel group may include at least one channel. The first channel group and the second channel group may extend parallel to each other in a first region of the surface and independent from each other in a second region of the surface.

Abstract: The pressure drop associated with the coolant flow in the coolant transition regions of a typical high power density, solid polymer electrolyte fuel cell stack can be significant. This pressure drop can be reduced by enlarging the height of the coolant ducts in this region of the associated flow field plate so that the ducts extend beyond the plane of the plate. The height change can be accommodated by offsetting the ducts in adjacent cells in the stack and by employing non planar MEAs in this region. By reducing the pressure drop, improved coolant flow sharing is obtained.

Abstract: A bipolar plate (30) for use in a fuel cell stack (10) includes one or more first metal layers (40a) having a tendency to grow an electrically passive layer in the presence of a fuel cell reactant gas and one or more second metal layers (40b) directly adjacent the one or more first metal layers (40a). The second metal layer has a tendency to resist growing any oxide layer in the presence of the fuel cell reactant gas to maintain a threshold electrical conductivity. The second metal layer also has a section for contacting an electrode (12, 14) and providing an electrically conductive path between the electrode (12, 14) and the first metal layer.

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