Henry H. Voss

Anode water removal: A water management and diagnostic technique for solid polymer fuel cells

Abstract A water management technique has been developed for solid polymer electrolyte fuel cells which demonstrates both performance and diagnostic benefits. Through this technique a substantial proportion of the water in the cathode can be removed via the anode fuel stream. This is accomplished by imparting a water concentration gradient through the polymer membrane, thereby increasing the back diffusion rate of water. A reduction in cathode overpotential is observed without noticeable increase in membrane resistance. The technique can be used to remove mass transport limitations at both high current densities and low oxidant stoichiometries.

Water management and stack design for solid polymer fuel cells

Abstract Water management has a major impact in the solid polymer fuel cell on overall system power, cost and efficiency. Single cell and stack performance may be adversely affected by the formation of liquid water, the dilution of reactant gases by water vapour, or by the dehydration of the solid polymer membrane. Peak fuel cell power is achieved typically at current densities at which performance is limited by mass transport. Improved water management at higher current densities not only increases peak power and efficiency but changes the profile of the power curve resulting in improved stability near the peak power operating point. Fuel cell water management can be accomplished by a number of approaches which include system design, stack operating conditions, stack hardware and membrane electrode assembly design. A number of these techniques have been successfully applied to both single cells and stacks. However, the options available for water management have to be assessed from an overall engineered system point of view.

Portable fuel cell power generator

The proliferation of electronic equipment in the market-place is driving the growth of portable power generators. The ability to store a sufficient amount of energy is the key issue for applications requiring high power levels or extended operation. The source of this energy, measured in watt-hours, can be either batteries or fuel for energy conversion systems. This paper compares energy storage methods and shows that fuel cell systems are well suited for portable power applications due to their use of high energy density storage capabilities.