Dynamic performance of a high-temperature PEM fuel cell - An experimental study

The dynamic behaviour of a fuel cell under varying of load is important for control and optimization. Experimental study on dynamic voltage of a HT-PEMFC (high-temperature PEM fuel cell) was conducted under 5 different currents operating on an anodic flow-through mode, dead-end mode with fixed purging intervals and dead-end mode with varying purging intervals after obtaining their forward and backward polarization curves. The results revealed that the hydration/dehydration processes of phosphoric acid used in HT-PEMFC would affect the dynamic behaviour of the fuel cell, and can be concluded by a few observations: (1) Hysteresis phenomenon was captured in the polarization study when cell current is swept from low to high (forward sweeping), then high to low (backward sweeping); (2) Under anodic flow-through mode, the magnitudes of voltage undershoots and overshoots were less severe at high current than those at the low current operation; (3) The peak performance of HT-PEMFC under anodic dead-end mode operation outperformed that under anodic flow-through mode. However, the performance of HT-PEMFC reduced gradually after the purging and the shape of the dynamic voltage curve under the longest purging interval overlapped with that under shorter purging intervals. (C) 2015 Elsevier Ltd. All rights reserved.