Analysis of CO gas continuous purging strategy for high-temperature proton exchange membrane fuel cells in dead-end anode mode

High-temperature proton exchange membrane fuel cells (HT-PEMFC) typically function in either dead-end anode (DEA) mode or anode recirculation mode, which may lead to the build-up of internal impurity gases, notably CO. To address this issue, purging is employed. However, this approach not only induces periodic voltage fluctuations and diminishes longevity, but it also potentially reduces hydrogen utilization and energy efficiency. This paper first analyzes the appropriate range of values for the continuous purge time (Tpv) and introduces a novel CO continuous purge strategy that enhances hydrogen utilization, energy efficiency, and minimizes voltage fluctuations. Subsequently, a theoretical model for the continuous purging strategy is developed, and the flow rates of the inlet and outlet valves are derived based on this model. Finally, theoretical formulas for hydrogen utilization and energy efficiency under the continuous purge strategy are derived. The results show that when the CO molar fraction threshold is 3 %, the utilization rate and energy efficiency of hydrogen under the continuous purge strategy achieve maximum values. The approach presented in this study not only addresses the issue of voltage fluctuation and high purging frequency during CO purging in DEA mode, but also theoretically improves the utilization of hydrogen and energy efficiency.