Proton exchange membrane fuel cells are promised to be the future choice for transportation power systems. Start-up procedure has significant impacts on fuel cell degradation. Most damages induced by start-up procedure relate to the hydrogen/air interface inside fuel cell. Studying on hydrogen/air interface is crucial for start-up degradation mitigation. It is difficult to monitor the internal distribution and transfer of hydrogen and oxygen by experiments. Therefore, this paper establishes a three-dimensional two-phase fuel cell model to simulate the gas concentration distribution in anode compartment, and proposes a start-up purging strategy by injecting hydrogen into the anode. The hydrogen/air interface removal process is simulated and visualized. Subsequently, the impacts of initial residual oxygen concentration and hydrogen flow rate on air removal in anode compartment are studied. It is proved that decrease initial oxygen concentration and increase hydrogen injection flow rate can significantly shorten the purge time. However, small flow rate of hydrogen injection is more economical for start-up purging when residual oxygen concentration is small. The results found in this paper can guide the experimental study of start-up purging strategy, and enrich high-performing and long-lasting design application theory of fuel cell.
Keywords Proton exchange membrane fuel cell, hydrogen/air interface, start-up purging strategy