Novel closed anode pressure-swing system for proton exchange membrane fuel cells

To overcome the low system efficiency and fuel efficiency in conventional recirculation systems and purging systems, a new anode closed pressure-swing system for proton exchange membrane fuel cells (PEMFCs) is proposed in this paper. Only two pressure regulators set at different pressures and a buffer tank are applied to produce pressure-swing inside the anode through the process of hydrogen feed and reaction, thereby achieving the anode-dead-end (ADE) operation (no purging). This system was successfully tested on a 20-cell open-cathode stack. The results indicate that the performance of the stack with the developed system is stable and efficient over 13,000 s, while its performance in ADE mode without purging deteriorates rapidly because of active area reduction. It can be concluded that the pressure swing system provides the following advantages: close to 100% hydrogen utilization; improved stack performance of around 12.5% for the power compare to the ADE mode with intermittent purging at 12 V load; improved humidification of the anode and membrane; and ease of implementation as there are no extra pumps.