Abstract: Reactant gas supply streams for solid polymer fuel cells may be heated and humidified using heat generated by the fuel cell and water vapor from the fuel cell exhaust. The heat and water vapor in the oxidant exhaust stream are sufficient to heat and humidify a reactant gas supply stream, preferably the oxidant supply stream. The heating and humidifying can be accomplished by flowing a reactant gas supply stream and a fuel cell exhaust gas stream on opposite sides of a water permeable membrane in a combined heat and humidity exchange apparatus. The method and apparatus are particularly suitable for use with air-cooled fuel cell systems and systems which employ near ambient pressure air as the oxidant gas supply.

Abstract: A flow field plate assembly for an electrochemical fuel cell comprises two flow field plates, each of which has channels formed on an inner surface of the plate. The plates are alignable with and engage each other such that their cooperating inner surfaces form at least one inner coolant fluid channel. The coolant channel has an essentially constant cross-sectional perimeter along its length, which is defined by the perimeters of the channels of the two plates and their difference in width at the cooperating plate surfaces. Additionally, a flow field plate assembly, which comprises a corrugated flow field plate and a staggered flow field plate, is structurally stronger under compressive load during the fuel cell operation.

Abstract: An aqueous ionomer gel having a high viscosity, particularly a proton conducting ionomer, as well as to related products incorporating such gels. Such aqueous ionomer gels are suitable for suspending catalysts for formation of catalyst inks, which in turn are suitable for screen printing on a variety of surfaces. Representative surfaces are the electrode or membrane surfaces in an electrochemical fuel cell. Methods for making aqueous ionomer gels are also disclosed.

Abstract: Apparatus, systems, and methods for bonding one element of an electrochemical cell or cell stack to another wherein a sealing grove with a complex cross-sectional shape receives and retains a bead of adhesive prior to being assembled. The complex cross-sectional shape has a raised portion sized to receive and retain the bead of adhesive, and at least one depressed portion to receive adhesive displaced from the raised portion during assembly. Embodiments of the invention incorporate raised portions with straight, beveled, curved, and rough surfaces to increase the strength of the bond between the respective elements.

Abstract: Low temperature fuel cells, e.g. solid polymer fuel cells, can operate directly on a fuel comprising dimethyl ether with dimethyl ether being oxidized at the fuel cell anode. Being highly soluble in water, dimethyl ether can be supplied as a liquid aqueous fuel solution. As a fuel, dimethyl ether provides similar power characteristics as methanol but typically with a greater Faradaic efficiency in liquid feed solid polymer fuel cells.

Abstract: An electrochemical fuel cell stack with improved reactant man folding and sealing includes a pair of separator plates interposed between adjacent membrane electrode assemblies. Passageways fluidly interconnecting the anodes to a fuel manifold and interconnecting the cathodes to an oxidant manifold are formed between adjoining non-active surfaces of the pairs of separator plates. The passageways extend through one or more ports penetrating the thickness of one of the plates thereby fluidly connecting the manifold to the opposite active surface of that plate, and the contacted electrode. The non-active surfaces of adjoining separator plates in a fuel cell stack cooperate to provide passageways for directing both reactants from respective stack fuel and oxidant supply manifolds to the appropriate electrodes. The fuel and oxidant reactant streams passageways are fluidly isolated from each other, although they both traverse adjoining non-active surfaces of the same pair of plates.

Abstract: Ion-exchange materials comprising a polymeric backbone and a plurality of pendent styrenic or fluoridated styrenic macromonomers covalently bonded thereto, wherein the plurality of pendent styrenic or fluorinated styrenic macromonomers comprise a uniform number of styrenic or fluoridated styrenic monomer repeat units, and wherein predominantly all of the styrenic or fluoridated styrenic monomer repeat units have at least one charged group. Processes for making such material, as well as products related thereto, are also disclosed. In a representative embodiment, the ion-exchange material is utilized as a proton-exchange membrane (PEM) for use in a PEM fuel cell.

Abstract: A method and apparatus increase the temperature of a fuel cell via reactant starvation at one or both electrodes. Reactant starvation at an electrode results in increased internal heat generation under load. Starvation conditions can be prolonged or intermittent and can be obtained, for example, by suitably reducing the supply rate of a reactant or by operating the fuel cell at sufficiently high current density so as to consume reactant faster than it is supplied. The method can allow for some generation of useful power by the fuel cell during start-up. The method is particularly suitable for starting up a solid polymer electrolyte fuel cell from temperatures below 0° C.

Abstract: A fuel cell system comprising a passive end cell heater for heating an end cell or cells within a fuel cell stack is disclosed. The fuel cell system comprises a fuel cell stack and a resistive heatable element connected in parallel to the fuel cell stack, wherein the resistive heatable element is adapted to heat an end cell of the fuel cell stack. A method for heating an end cell in a fuel cell stack is also disclosed.

Abstract: Disclosed are reactant feed apparatus for liquid-fueled direct feed fuel cells, including miniaturized versions thereof. More specifically, disclosed is a fuel flow device for delivering liquid fuel to such direct feed fuel cells. The fuel flow device comprises a fuel flow-routing device and an enclosure/partition assembly containing the liquid fuel to be delivered. When the fuel flow device is fluidly connected to the fuel cell, it operates to deliver the liquid fuel to an anode flow field thereof by using the pressurized anodic exhaust gases exiting therefrom as the source of power for pumping the liquid fuel from the enclosure into the fuel cell.

Abstract: A compact, multitube steam reformer converts a fuel into a reformate stream comprising hydrogen. In one embodiment, the reformer comprises a closed vessel and a burner disposed within the vessel. The burner comprises a start fuel manifold for receiving and distributing a start fuel stream, an oxidant manifold for receiving and distributing an oxidant stream, and a burner fuel manifold for receiving and distributing a burner fuel stream. The oxidant manifold comprises a plurality of oxidant distribution tubes, each having an inlet end and an outlet end, disposed in a separator member. The burner fuel manifold comprises a plurality of burner fuel distribution tubes, each having an inlet end and an outlet end. The burner fuel distribution tubes extend through the start fuel manifold and the oxidant manifold and are fluidly isolated therefrom.

Abstract: Fuel cell system comprising at least one fuel cell which includes an anode compartment and a cathode compartment which are separated from one another by a proton-conducting membrane, further comprising a cathode feeder for delivering oxygen-containing gas to the cathode compartment, an anode feeder for delivering a liquid coolant/fuel mixture to the anode compartment, the anode compartment being disposed in an anode circuit which comprises a gas separator and a pump, and cooling of the coolant/fuel mixture circulating in the anode circuit is effected by the fuel cell which is designed for operation involving water break-through from the anode compartment into the cathode compartment. The evaporation cooling thus achieved in the fuel cell results in cooling of the coolant/fuel mixture at a steady-state operating temperature which is established in the fuel cell as a function of the membrane properties and the speed of the pump, thus obviating the need for any additional cooler in the anode circuit itself.

Abstract: An electric power plant includes an array of fuel cell systems. The fuel cell systems are electrically couplable in series and/or parallel combinations to provide a variety of output powers, output current and/or output voltages. The fuel cell systems are “hot swappable” and redundant fuel cell systems may automatically replace faulty fuel cell systems to maintain output power, current and/or voltage.

Abstract: An electrochemical fuel cell having reactant flow passages with a non-uniform design to increase reactant access to an adjacent fluid distribution layer at the outlet region as compared to the inlet region. In an embodiment, at least one reactant flow passage is narrower at the inlet than at the outlet, with a substantially constant cross-sectional area maintained along its length. Coolant channels may optionally be incorporated in the fluid flow plate to provide increased cooling at the reactant inlet. The plates may vary in thickness and run in counter-flow to improve efficient stacking of the fuel cells in a fuel cell stack with reactant passages of varying depth. In another embodiment, electrically conductive, masking foil covers a portion of at least one reactant flow passage in the inlet region, but does not extend the length of the passage.

Abstract: A method and apparatus are provided for distributing water produced by the electrochemical reaction to ion-exchange membranes in an array comprising a plurality of electrochemical fuel cell stacks. Water distribution within individual fuel cell stacks within the array is improved to reduce membrane dryness near the oxidant stream inlet and to also reduce saturation of the oxidant stream near the oxidant stream outlet, thereby reducing electrode flooding. The method comprises periodically reversing the oxidant stream flow direction within at least one of the plurality of fuel cell stacks. The apparatus comprises an oxidant stream flow switching device for periodically switching the flow direction of an oxidant stream through an individual fuel cell stack. In one embodiment the apparatus further comprises a water recycler for capturing water from the oxidant exhaust stream and returning the captured water to the oxidant stream when the flow direction is reversed.

Abstract: A quick connect fitting is provided for connecting a pressure fluid container to an intake port of a consumer system, such as a fuel cell stack. The fitting includes a solenoid-activated valve for controlling outflow of fluid from the pressure fluid container. The valve is biased to a closed position when no electrical power is supplied to the solenoid. In one embodiment the fitting incorporates a coupling mechanism for removable attachment to the intake part of the consumer system.

Abstract: Non-noble metal transition metal catalysts can replace platinum in the oxidation reduction reaction (ORR) used in electrochemical fuel cells. A RuxSe catalyst is prepared with comparable catalytic activity to platinum. An environmentally friendly aqueous synthetic pathway to this catalyst is also presented. Using the same aqueous methodology, ORR catalysts can be prepared where Ru is replaced by Mo, Fe, Co, Cr, Ni and/or W. Similarly Se can be replaced by S.

Abstract: The present invention is generally directed to systems and methods for distributing a non-odorized gas. In one embodiment, an inner pipe containing a non-odorized gas at a first pressure is routed through an outer pipe adapted to contain an odorized fluid at a second pressure less than the first pressure. As a result of the pressure differential, a leak in the inner pipe will not permit the odorized fluid in the outer pipe to flow into the inner pipe. When the non-odorized gas is hydrogen, this prevents a stream of hydrogen gas that is possibly contaminated with odorants from reaching a fuel cell. Furthermore, a leak in the outer pipe or a leak in both the inner and outer pipes will result in the release of the odorized fluid into the environment, allowing leaks to be detected before dangerous or harmful levels are reached.

Abstract: A method for coating an ion-exchange membrane with a catalyst layer by first heating a surface of the membrane to thereby soften the surface, followed by deposition of a catalyst composition and compaction into the ion-exchange membrane to produce a catalyst-coated membrane. Heating of the ion-exchange membrane may be at a temperature between 20° C. and 50° C., typically between 30° C. and 40° C., above the glass transition temperature of the dry ion-exchange membrane. In one embodiment, the catalyst composition is fluidized in a fluidized bed reactor prior to being deposited on the membrane surface. A system for coating the ion-exchange membrane is also provided. The catalyst-coated membrane is particularly useful in electrochemical fuel cells.

Abstract: An electrical contacting device for a fuel cell assembly comprises a printed circuit board comprising electrically conductive regions for providing reliable electrical contact with fuel cell components of the fuel cell assembly. Preferably the printed circuit board is flexible. The contacting device may be used, for example, for monitoring cell operating parameters like current or voltage, for short circuiting or by-passing individual cells or for directing signals to the stack.