Fan the flame with water: Operating PEM fuel cells with dry feeds

To simplify the vexing water-management problem in polymer electrolyte (PEM) fuel cell, the fuel delivery system was reengineered and the water produced used to autohumidify the membrane. The standard serpentine flow pattern was replaced by an open plenum - creating the equivalent of a stirred tank reactor (STR). The STR PEM fuel cell current is ignited by a one-time injection of water into the fuel cell to hydrate the membrane; after current ignition, the autohumidified fuel cell operates for thousands of hours. Autohumidifed fuel cells have multiple steady states analogous to a flame. The STR design could exploit gravity to facilitate the removal of liquid water. Orienting the fuel cell vertically and eliminating concave surfaces creates a channel-less self-draining PEM fuel cell that operates with dry feeds and does not flood. The channel-less gravity-assisted flow design could control power output independent of temperature (no temperature control would be required) with 100% fuel utilization.