Abstract: A fuel cell assembly provides for direct water delivery to water injection points in the active area of fluid flow field plates of the assembly. The fluid flow field plate has a plurality of channels formed in the surface thereof which extend across the surface of the plate in a predetermined pattern, defining the active areas of the plate. A distribution foil has a plurality of channels formed in a surface thereof which channels extend from a first edge of the distribution foil to a second edge of the distribution foil. The channels terminate at the second edge at positions substantially coincident with respective ones of the field plate channels at water injection points. A cover foil extends over the distribution foil to enclosed the distribution foil channels and thereby form conduits for the water between the two foils.

Abstract: An electrochemical fuel cell having an anode, an ion transfer membrane and a cathode has liquid water delivered to the fluid flow channels within the cathode so as to maintain a relative humidity of 100% throughout the fluid flow channels. A calibration method and apparatus is described for determining an optimum quantity or range of quantities of liquid water to be delivered to the cathode fluid flow channels under varying operating conditions. An operating method and apparatus is described that ensures an optimum quantity of liquid water is delivered to the cathode fluid flow channels under varying operating conditions.

Abstract: An electrochemical fuel cell having an anode, an ion transfer membrane and a cathode has liquid water delivered to the fluid flow channels within the cathode so as to maintain a relative humidity of 100% throughout the fluid flow channels. A calibration method and apparatus is described for determining an optimum quantity or range of quantities of liquid water to be delivered to the cathode fluid flow channels under varying operating conditions. An operating method and apparatus is described that ensures an optimum quantity of liquid water is delivered to the cathode fluid flow channels under varying operating conditions.

Abstract: A bipolar fluid flow flied plate for a fuel cell delivers fuel to a porous anode electrode and oxidant to an adjacent porous cathode electrode. The flow field plate comprises an electrically conductive, non-porous sheet into which fluid flow conduits are formed. A first fluid flow channel is patterned into a first face of the sheet and a second fluid flow channel patterned into the opposite face of the sheet. The pattern of the first channel comprises an interdigitated comb that co-operates with a pattern of the second channel comprising a continous serpentine path, so that no portion of the first channel directly overlies the pattern of the second channel over a substantial active area of the sheet. This allows the channels to be formed with combined depths that exceed the total plate thickness, thereby increasing fluid flow volumes.

Abstract: An electrochemical fuel cell having an anode, an ion transfer membrane and a cathode has liquid water delivered to the fluid flow channels within the cathode so as to maintain a relative humidity of 100% throughout the fluid flow channels. A calibration method and apparatus is described for determining an optimum quantity or range of quantities of liquid water to be delivered to the cathode fluid flow channels under varying operating conditions. An operating method and apparatus is described that ensures an optimum quantity of liquid water is delivered to the cathode fluid flow channels under varying operating conditions.

Abstract: A fuel cell having an anode, a cathode and an ion exchange membrane is supplied by hydrogen fuel through an anode fuel delivery conduit. A recirculation loop is provided to recycle gases in the fuel delivery conduit to a mixing point where a controlled flow rate of fuel is supplied and mixed therewith. Any oxidant species remaining in the fuel delivery conduit are thereby combusted in a controlled manner to avoid damage to the fuel cell membrane-electrode assembly. Small quantities of oxidant may be deliberately introduced into the fuel delivery conduit to generate water vapor and heat to pre-condition the fuel delivered to the anode. Such preconditioning assists in hydration control of the membrane, and temperature control of the membrane-electrode assembly for optimum fuel cell performance.

Abstract: An electrochemical fuel cell having an anode, an ion transfer membrane and a cathode has liquid water delivered to the fluid flow channels within the cathode so as to maintain a relative humidity of 100% throughout the fluid flow channels. A calibration method and apparatus is described for determining an optimum quantity or range of quantities of liquid water to be delivered to the cathode fluid flow channels under varying operating conditions. An operating method and apparatus is described that ensures an optimum quantity of liquid water is delivered to the cathode fluid flow channels under varying operating conditions.