The Effect of Temperature and Load as a Stressor for Proton Exchange Membrane Fuel Cells Durability

Abstract

To improve the Proton Exchange Membrane Fuel Cells (PEMFCs) suitability for heavy-duty vehicles a higher operating temperature is required. However, a higher operating temperature is often associated with higher degradation rates. In this work we investigate the effects of temperature and load on the degradation of PEMFCs operating at temperatures between 80 and 120 °C. The measurements are done with commercial state-of-the-art membrane electrode assemblies (MEAs), and the ageing is achieved through galvanostatic holds. The results show that an increased operating temperature causes a more rapid decrease in performance. The main loss in performance is linked to changes in the membrane and ionomer in the membrane electrode assembly. The increased operating temperature causes accelerated membrane failure, resulting in higher hydrogen crossover due to pinhole formation. It is also seen that the ionomer in the cathode degrades faster at elevated temperatures, and that a lower applied load reduces the rate. Further analysis shows small and similar changes in the electrode thickness and particle sizes for all temperatures. Overall, it is concluded that while an elevated temperature reduces the lifetime of a fuel cell, operating at elevated temperatures for shorter durations can be feasible.

Keywords: PEMFC, Intermediate temperature, Degradation