Evaluation of fin structure effects on a heated air-breathing polymer electrolyte membrane (PEM) fuel cell

• Schlieren/infrared imaging for visualization of airflow/temperature above fuel cell.
• Fins increase airflow at high temperature and result in improved performance.
• EIS data show less mass transport losses with fins at high temperature.

The impact of fin structures and temperature variations on the performance of air-breathing, polymer electrolyte membrane (ABPEM) fuel cells is investigated using polarization testing, electrochemical impedance spectroscopy, and imaging diagnostics (infrared pyrometry and Schlieren). The fuel cell body is designed to have a large thermal mass compared to an active area size of 10 cm2, which prevents self-heating and enables accurate temperature control of the fuel cell using an external heater. The fuel cell is tested using three different fin structures and at four different temperatures (Room, 30 °C, 40 °C, 50 °C). At higher temperatures, significant enhancement of performance is observed. From the Schlieren images and calculated Nusselt numbers, it is determined that at higher temperatures, the fin structures increase convective heat transfer rate or vertical air velocity, which provides oxygen to the fuel cell at a faster rate, resulting in enhancement of the fuel cell performance. The insight into the use of fin structures to enhance the effects of convection at various temperatures presented here can provide optimized design parameters for new air-breathing fuel cells in the future.