• In open-cathode fuel cells, membrane dehydration dominates at low currents, while anode flooding dominates at high currents. • SCU control is effective below 0.3 A/cm², increasing voltage by up to 0.024 V with a 15% efficiency loss. • Purge control is applied over the entire range, improving voltage by up to 0.034 V with 14% reduced fuel efficiency. • Optimized SCU and purge control maintains cell performance while improving fuel efficiency by up to 20%. • The proposed strategy provides practical guidelines for efficient open-cathode fuel cell operation. In this study, the effects of short-circuit unit (SCU) and purge control on the performance and fuel efficiency of open-cathode fuel cells are investigated by considering internal water distribution. First, the effect of SCU control on fuel cell performance is investigated in the low current density region. SCU control effectively supplies additional water to the membrane, thereby reducing ohmic overpotential and enhancing cell voltage by approximately 0.024 V at a current density of 0.1 A/cm². Next, the effect of purge control on liquid water accumulation in the anode channel is examined at high current density conditions. Purge control successfully mitigates flooding and improves cell voltage by up to 0.034 V at 0.7 A/cm²; however, excessive SCU and purging leads to increased hydrogen loss, reducing fuel efficiency. Finally, an optimized water management control strategy is proposed by coordinating SCU and purge control according to operating conditions. The proposed strategy improves fuel efficiency by approximately 5.7% at high current densities while maintaining comparable cell voltage, providing practical guidelines for efficient and robust operation of open-cathode fuel cells.
Han et al. (Fri,) studied this question.