PEM fuel cell stack with dead-ended anode for electric aviation: Measurement, simulation, and optimization of purge strategy

Polymer electrolyte membrane fuel cell (PEMFC) systems for electric aircraft require high fault tolerance on a system level. Operating a PEMFC with a dead-ended anode ( DEA ) instead of an anode gas recirculation loop reduces the number of components in the system and can therefore increase the fault tolerance. With a DEA , the anode gas is not recirculated, and the purge valve remains predominantly closed. However, because nitrogen or liquid water can accumulate at the anode outlet and lead to hydrogen starvation, the purge valve is periodically opened. In this work, a simulation model of a PEMFC stack is validated using 137 operating points measured with a PEMFC stack and a DEA . The simulated and measured data agree well under both steady-state and transient conditions. Mass flows and pressure drops fell within sensor uncertainty, and the average cell voltage error was below 9 m V . The purge strategy is optimized by adjusting the purge duration and the purge interval to increase the efficiency of the PEMFC stack up to an overall efficiency of 57 % for the operating point investigated. A time span between two purge events below 30 s was found to be optimal for the operating point investigated. • Simulation model of a PEMFC stack with water separator and purge valve is described. • Good agreement to 137 measured operating points with a dead-ended anode was achieved. • Optimizing purge strategy significantly increases efficiency and reduces degradation. • A time span between two purge events below 30 s was found to be optimal.