Abstract: A diffusion medium for use in a PEM fuel cell comprising a thin perforated layer having variable size and frequency of perforation patterns incorporated into a microporous layer on a first side of a porous substrate layer, wherein the diffusion medium is adapted to improve water management and performance of the fuel cell.

Abstract: Fuel cells contain diffusion media having vapor-deposited fluorocarbon polymers on a conductive substrate. A diffusion medium for use in a PEM fuel cell contains hydrophobic and hydrophilic areas for improved water management.

Abstract: Diffusion media for fuel cell is made by preparing an aqueous dispersion comprising a powder resin, a binder material, and a fiber material comprising carbon fibers, of these; forming a layer of the dispersion on a support; removing water from the layer to form a fiber layer; molding the fiber layer; and carbonizing or graphitizing the molded layer.

Abstract: A gas diffusion media for a fuel cell, such as a proton exchange membrane fuel cell, is provided. The gas diffusion media includes carbonizable acrylic pulp fibers instead of conventional phenolic resin as a binder material. The acrylic fibers are mixed with the carbon fiber dispersion during the papermaking step, thus eliminating the phenolic resin impregnation step typically associated with conventional gas diffusion media manufacturing processes. The mat is then cured and carbonized to produce gas diffusion media.

Abstract: A method for enabling consumers to push funds from a traditional open loop account to a closed loop account, and back. At the request of a consumer, funds are transferred to an open loop account of an intermediary payment system that holds or keeps track of virtual closed loop accounts for each consumer and virtual closed loop accounts for individual merchants or service providers. The consumer may use an associated closed loop card to make a purchase at the merchant or service provider that will cause funds to be transferred from the consumer's virtual closed loop account to the merchant or service provider's closed loop account. Thereafter, the funds are transferred from the intermediary payment system to an open loop account belonging to the merchant or service provider.

Abstract: A method for enabling consumers in a gaming context to push funds from a traditional open loop account to a closed loop account, and back. At the request of a consumer, funds are transferred to an open loop account of an intermediary payment system that holds or keeps track of virtual closed loop accounts for each consumer and virtual closed loop accounts for individual games, casinos or gaming establishments. The consumer may use an associated closed loop card to place a bet at the gaming establishment that will cause funds to be transferred from the consumer's virtual closed loop account to the gaming establishment's closed loop account. Thereafter, the funds are transferred from the intermediary payment system to an open loop account belonging to the gaming establishment.

Abstract: A fuel cell stack that includes an actuating device or devices for selectively providing interdigitated reactant gas flow and straight reactant gas flow through reactant gas flow channels to reduce water accumulation in the diffusing media layers of the stack. In one embodiment, the fuel cell stack employs internal actuators that selectively close the inlet end of every other flow channel and the outlet end of every other opposite flow channel to provide the interdigitated flow. In another embodiment, the interdigitated flow is provided by external actuation where two inlet manifolds and two outlet manifolds are provided. One input manifold is closed to close the input ends of every other flow channel and one outlet manifold is closed to close the output ends of every other opposite flow channel.

Abstract: Systems and methods for remotely causing a request for authorization to charge a card, that is otherwise active, to be denied. In one embodiment, an access controller receives a call from a card holder and analyzes ANI and DNIS data received during call setup for the call to select a card account and an action (e.g., turn account OFF) to be taken with respect to the card account. The access controller formulates and sends a message to an account authorization processing system to cause the account authorization processing system to thereafter deny requests for authorization to charge the card account. A subsequent call to the access controller from the same caller (i.e., a same ANI) will reverse account closure and allow card authorization to proceed. Feedback, in the form of an Instant Message (IM), email, or audible signal (busy, ringing) when making the call, may be provided to indicate the success of a change to the state of the account.

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: A fuel cell system with a proton exchange membrane. There is a cathode catalyst layer overlying the first face of the proton exchange membrane, and a cathode diffusion layer overlying the cathode catalyst layer. There is an anode catalyst layer overlying the second face of the proton exchange membrane, and an anode diffusion layer overlying the anode catalyst layer. The cathode diffusion layer has a water vapor permeance of less than about 3×10?4 g/(Pa s m2) at 80° C. and 1 atmosphere. The invention also relates to cathode diffusion layers for fuel cell systems.

Abstract: A fuel cell system that employs a diode electrically coupled between bipolar plates in a fuel cell of a fuel cell stack for preventing the fuel cell between the plates from reversing its polarity. The diode is a thin-sheet p-n diode including doped semiconductor layers and has a thickness relative to the thickness of the MEA in the fuel cell so that the overall stack thickness does not increase. When the fuel cell is operating properly the diode does not conduct and all of the current through the fuel cell goes through the MEA. If the electric load on the stack increases to a level beyond the capability of the fuel cell, where the potential across the fuel cell goes significantly below zero, the diode will begin to conduct so that any current that cannot travel through the MEA with the cell voltage less than one negative forward diode voltage drop is able to go around the MEA through the diode.

Abstract: Specially prepared gas diffusion media improve the performance of PEM fuel cells. The media are made by first dipping an electrically conductive porous material such as carbon fiber paper into a suspension of hydrophobic polymer and drying the paper to create a desired deposition pattern of hydrophobic polymer on the substrate. Then a paste containing a fluorocarbon polymer and carbon particles is applied to a desired side of the substrate, and thereafter the paste and hydrophobic polymer are sintered together at high temperature on the paper. In particular, nonionic surfactants remain on the carbon fiber paper after the initial hydrophobic polymer is applied to the electrically conductive porous material. When the paste is coated on the dried paper, the paste is in contact with a hydrophilic surface.

Abstract: Gas diffusion media for use in fuel cells are provided that contain a pattern of deposited hydrophobic polymer such that less than 100% of the surface of the diffusion media is covered with hydrophobic polymer. The media are made by first wetting a sheet of carbon fiber paper in an aqueous emulsion of the hydrophobic polymer. The wetted sheet is contacted with a pattern member containing one or more openings oriented to correspond to a predetermined or desired pattern of hydrophobic polymer deposition. While still in contact with the pattern member, the sheet is heated or otherwise treated to cause evaporation of the water from the sheet. Evaporation while in contact with the pattern member takes place in such a way that hydrophobic polymer is concentrated in the sheet at the openings of the pattern member by the process of evaporation.

Abstract: The present invention is directed to an electroconductive element within an electrochemical cell that improves water management. The electroconductive element comprises an impermeable electrically conductive element and a porous liquid distribution media disposed along a major surface of the conductive element. Preferably, the liquid distribution media is in direct contact and fluid communication with a fluid distribution layer disposed between the membrane electrode assembly (MEA) and the liquid distribution media, so that liquids are drawn from the MEA through the fluid distribution layer to and through the liquid distribution media. The liquid distribution media transports liquids away from the MEA in the fuel cell. Methods of fabricating and operating fuel cells and electroconductive elements according to the present invention are also contemplated.

Abstract: A fuel cell system with a proton exchange membrane. There is a cathode catalyst layer overlying the first face of the proton exchange membrane, and a cathode diffusion layer overlying the cathode catalyst layer. There is an anode catalyst layer overlying the second face of the proton exchange membrane, and an anode diffusion layer overlying the anode catalyst layer. The cathode diffusion layer has a water vapor permeance of less than about 3×10?4 g/(Pa s m2) at 80° C. and 1 atmosphere. The invention also relates to cathode diffusion layers for fuel cell systems.

Abstract: An electrically conductive fluid distribution element for use in a fuel cell having a conductive metal substrate and a layer of conductive non-metallic porous media. The conductive non-metallic porous media has an electrically conductive metal deposited along a surface in one or more metallized regions. The metallized regions improve electrical conductance at contact regions between the metal substrate and the fluid distribution media.

Abstract: Favorable performance of diffusion media in fuel cells has found to be correlated to a parameter (the C/F ratio) that relates to a spatial and thickness distribution of the hydrophobic fluoropolymer on the carbon fiber substrate structure of the medium. Suitable diffusion media may be chosen from among commercially coated diffusion media by measuring the C/F ratio by means of energy dispersive spectroscopy, and choosing the diffusion media if the value of the C/F ratio is within the preferred range. Alternatively, the diffusion media may be manufactured with an improved process that consistently yields values of C/F ratio in the desired range.

Abstract: A gas diffusion media and method of making are provided including the formation of a carbon fiber paper which is heated to a carbonization temperature without exceeding a graphitization temperature. The discovery that a final high temperature heat treatment step in the graphitization temperature zone is not necessary to make effective gas diffusion media for PEM fuel cells greatly reduces the cost associated with the high temperature final heat treatment and also allows for the processing of the diffusion media in a roll.

Abstract: A diffusion media is provided for implementation with a PEM fuel cell. The diffusion media is a permeable sheet that is rigid along a transverse axis, flexible along a lateral axis and has a substantially incompressible thickness. The diffusion media is able to be mass produced in large sheets and rolled along the lateral axis for transport and storage. The rigidity of the transverse axis is provided by either inclusion of larger fibers or metallic strips aligned in the transverse direction and prevents tenting of the diffusion media into flow channels of the PEM fuel cell. The diffusion media is water and gas permeable and electrically conductive.