Abstract: A method of manufacturing a plate for a fuel cell includes the steps of providing flow channels in a fuel cell plate. Multiple fuel cell plates are joined into a cell stack assembly. A blocking plate is affixed to the fuel cell plate and at least partially obstructs the flow channels. The blocking plate is affixed to the fuel cell plate after the plates have been arranged into the cell stack assembly. The resulting fuel cell provides a fuel cell plate having a perimeter with an edge. The fuel cell plate includes flow channels extending to the edge. The blocking plate is affixed to the fuel cell plate at the edge to at least partially block the flow channel. In this manner, an inexpensive fuel cell plate may be used, and the blocking plate can be configured to create terminated flow channels, which may be used to provide an interdigitated flow field.

Abstract: An example method of controlling a fuel cell power plant based on provided power includes selectively varying an electrical resistance of the variable resistive device responsive to at least one of a power provided by the fuel cell power plant, a current provided by the fuel cell power plant, or a voltage decay rate.

Abstract: An example fuel cell assembly includes a plate having channels configured to facilitate movement of a fuel cell fluid near an area of active flow of fuel cell. The channels include portions having a varying depth that extend laterally outside of the area of active flow.

Abstract: A fuel cell power plant (36) has vertical fuel cells (102) each sharing a half of a hybrid separator plate (100) which includes a solid fuel flow plate (105) having horizontal fuel flow channels (106) on one surface and coolant channels (108) on an upper portion of the opposite surface, bonded to a plain rear side of a porous, hydrophilic oxidant flow field plate (115) having vertical oxidant flow channels (118). Coolant permeates through the upper portion of the porous, hydrophilic oxidant flow field plates and enters the oxidant flow channels, where it evaporates as the water trickles downward through the oxidant flow field channels, thereby cooling the fuel cell.

Abstract: An example seal assembly includes a first seal that is configured to be placed between a fuel cell manifold and a fuel cell stack. The first seal establishes a recessed area within a side of the first seal that faces the fuel cell stack. The fuel cell seal assembly further includes a second seal that is configured to be placed between the first seal and the fuel cell stack within the recessed area. An example method of sealing a fuel cell interface includes holding a first seal within a groove established within a manifold and holding a second seal within a recessed area established within the second seal. The method limits flow of a fuel cell fluid using a first seal and the second seal.

Abstract: An example method of operating a fuel cell system includes calculating the rate of water produced in the fuel cell stack, determining the rate of water exiting the system, and controlling the condenser temperature to maintain the cathode gas exit temperature from the condenser below the temperature required to maintain water balance in the fuel cell system. The method collects the condensed vapor as water and purges a portion of the collected water containing contaminants from the system.

Abstract: The invention is a hydrogen passivation shut down system for a fuel cell power plant (10, 200). During shut down of the plant (10, 200), hydrogen fuel is permitted to transfer between an anode flow path (24, 24?) and a cathode flow path (38, 38?) while a low-pressure hydrogen generator (202) selectively generates an adequate amount of hydrogen and directs flow of the low-pressure hydrogen into the fuel cell (12?) downstream from a hydrogen inlet valve (52?) to maintain the fuel cell (12?) in a passive state.

Abstract: The invention is a hydrogen passivation shut down system for a fuel cell power plant (10, 200). During shut down of the plant (10, 200), hydrogen fuel is permitted to transfer between an anode flow path (24, 24?) and a cathode flow path (38, 38?). A passive hydrogen bleed line (202) permits passage of a smallest amount of hydrogen into the fuel cell (12?) necessary to maintain the fuel cell (12?) in a passive state. A diffusion media (204) may be secured in fluid communication with the bleed line (202) to maintain a constant, slow rate of diffusion of the hydrogen into the fuel cell (12?) despite varying pressure differentials between the shutdown fuel cell (12?) and ambient atmosphere adjacent the cell (12?).

Abstract: A method of controlling an amount of liquid in a fuel cell includes increasing the oxygen utilization within the fuel cell to increase heat. The heat reduces the amount of liquid in the fuel cell. A disclosed example method includes decreasing a supply of air to the fuel cell to lower a fuel cell voltage by increasing the oxygen utilization. The example method includes maintaining an essentially electrical current density while decreasing the supply of air.

Abstract: A fuel cell is disclosed that includes an electrode assembly arranged between a cathode and an anode. The anode and cathode have lateral surfaces adjoining lateral surface of the electrode assembly and respectively include fuel and oxidant flow fields. Interfacial seals are not arranged between the lateral surfaces. Instead, a sealant is applied to the anode, the cathode and the electrode assembly to fluidly separate the fuel and oxidant flow fields. In one example, the adjoining lateral surfaces are in abutting engagement with one another. The sealant is applied in a liquid, uncured state to perimeter surfaces of the electrode assembly, the anode and the cathode that surround the lateral surfaces.

Abstract: Fuel cell systems (100, 400) and related methods involving accumulators (106, 200, 300, 406) with multiple regions (R1, R2; R1?, R2?) of differing water fill rates are provided. At least one accumulator region with a relatively more-rapid fill rate (R2; R2?) than another accumulator region (R1; R1?) is drained of water at shutdown under freezing conditions to allow at least that region to be free of water and ice. That region is then available to receive water from and supply water to, a fuel cell (102; 402) nominally upon start-up. The region having the relatively more-rapid fill rate (R2; R2?) may typically be of relatively lesser volume, and may be positioned either relatively below or relatively above the other region(s).

Abstract: A method for making a membrane electrode assembly includes the steps of providing a membrane electrode assembly including an anode including a hydrogen oxidation catalyst; a cathode; a membrane disposed between the anode and the cathode; and depositing a peroxide decomposition catalyst in at least one position selected from the group consisting of the anode, the cathode, a layer between the anode and the membrane and a layer between the cathode and the membrane wherein the peroxide decomposition catalyst has selectivity when exposed to hydrogen peroxide toward reactions which form benign products from the hydrogen peroxide. The peroxide decomposition catalyst can also be positioned within the membrane. Also disclosed is a power-generating fuel cell system including such a membrane electrode assembly, and a process for operating such a fuel cell system.

Abstract: The fuel cell device includes an electrode assembly. A gas diffusion layer is on each side of the electrode assembly. A solid, non-porous plate is adjacent each of the gas diffusion layers. A hydrophilic soak up region is near an inlet portion of at least one of the gas diffusion layers. The hydrophilic soak up region is configured to absorb liquid water from the electrode assembly when the fuel cell device is shutdown.

Abstract: The oxidant inlets of the reactant gas flow field grooves (41) of a fuel cell (11) which suffers a crossover between the fuel and oxidant flow fields, due to a leak in the seals, the maxtrix or the membrane of the fuel cell, are blocked with a liquid (50) which cures in place, hot glue, two-part epoxy, or fluoroelastomers. This prevents heating as a result of combusting fuel with oxygen near the site, which avoids excessive heating and damaging of successive fuel cells. As a result, a fuel cell power plant (8) can continue to operate with only a minor loss of voltage and power, thereby avoiding the need to tear down the stack by loosening the tie-bolts. Voltage and hydrogen levels may be used to detect the crossover. The particular cell (11) with the leak can be determined by voltage or hydrogen monitoring, or by immersing the stack in a liquid while applying gas to the fuel inlet of the stack.

Abstract: An exemplary fuel cell device includes an electrode assembly. A hydrophobic gas diffusion layer is on a first side of the electrode assembly. A first, solid, non-porous plate is adjacent the hydrophobic gas diffusion layer. A hydrophilic gas diffusion layer is on a second side of the electrode assembly. A second flow field plate is adjacent the hydrophilic gas diffusion layer. The second flow field plate has a porous portion facing the hydrophilic gas diffusion layer. The porous portion is configured to absorb liquid water from the electrode assembly when the fuel assembly device is shutdown.

Abstract: A fuel cell stack (31) includes a plurality of fuel cells (9) each having an electrolyte such as a PEM (10), anode and cathode catalyst layers (13, 14), anode and cathode gas diffusion layers (16, 17), and water transport plates (21, 28) adjacent the gas diffusion layers. The cathode diffusion layer of cells near the cathode end (36) of the stack have a high water permeability, such as greater than 3×10?4 g/(Pa s m) at about 80° C. and about 1 atmosphere, whereas the cathode gas diffusion layer in cells near the anode end (35) have water vapor permeance greater than 3×10?4 g/(Pa s m) at about 80° C. and about 1 atmosphere. In one embodiment, the anode gas diffusion layer of cells near the anode end (35) of the stack have a higher liquid water permeability than the anode gas diffusion layer in cells near the cathode end; a second embodiment reverses that relationship.

Abstract: A fuel cell power plant (10) includes a fuel cell (12) having a membrane electrode assembly (MEA) (16), disposed between an anode support plate (14) and a cathode support plate (18), the anode and/or cathode support plates include a hydrophilic substrate layer (80, 82) having a predetermined pore size. The pressure of the reactant gas streams (22, 24) is greater than the pressure of the coolant stream (26), such that a greater percentage of the pores within the hydrophilic substrate layer contain reactant gas rather than water. Any water that forms on the cathode side of the MEA will migrate through the cathode support plate and away from the MEA. Controlling the pressure also ensures that the coolant water will continually migrate from the coolant stream toward the anode side of the MEA, thereby preventing the membrane from becoming dry. Proper pore size and a pressure differential between coolant and reactants improves the electrical efficiency of the fuel cell.

Abstract: A membrane electrode assembly is provided which includes an anode; a cathode; a membrane between the anode and the cathode; and a protective layer between the membrane and at least one electrode of the anode and the cathode, the protective layer having a layer of ionomer material containing a catalyst, the layer having a porosity of between 0 and 10%, an ionomer content of between 50 and 80% vol., a catalyst content of between 10 and 50% vol., and an electrical connectivity between catalyst particles of between 35 and 75%. A configuration using a precipitation layer to prevent migration of catalyst ions is also provided.

Abstract: A method of controlling an amount of liquid in a fuel cell includes increasing the oxygen utilization within the fuel cell to increase heat. The heat reduces the amount of liquid in the fuel cell. A disclosed example method includes decreasing a supply of air to the fuel cell to lower a fuel cell voltage by increasing the oxygen utilization. The example method includes maintaining an essentially electrical current density while decreasing the supply of air.

Abstract: The invention is a hydrogen passivation shut down system for a fuel cell power plant (10, 200). During shut down of the plant (10, 200), hydrogen fuel is permitted to transfer between an anode flow path (24, 24?) and a cathode flow path (38, 38?). A passive hydrogen bleed line (202) permits passage of a smallest amount of hydrogen into the fuel cell (12?) necessary to maintain the fuel cell (12?) in a passive state. A diffusion media (204) may be secured in fluid communication with the bleed line (202) to maintain a constant, slow rate of diffusion of the hydrogen into the fuel cell (12?) despite varying pressure differentials between the shutdown fuel cell (12?) and ambient atmosphere adjacent the cell (12?).