A comprehensive system-level model for performance evaluation of proton exchange membrane fuel cell system with dead-ended anode mode

In this study, a comprehensive system-level model was developed for a proton exchange membrane fuel cell (PEMFC) system with a dead-ended anode (DEA) mode. The global system model consisted of a series of local component models, including PEMFC stack, manifolds, air compressor, humidifier and valves. Membrane water conversion and N2 crossover were simultaneously considered in the stack component model. Based on the system-level model, the output voltage and water content of the PEMFC and the compressor power consumption at various currents and ambient pressures were investigated. Additionally, the dynamic behaviors of the cell voltage, its water content, and system hydrogen utilization rate were predicted for two legislated driving cycles-the New European Driving Cycle (NEDC) and the Worldwide Harmonized Light Vehicle Test Procedure (WLTP). The fuel cell voltage fluctuation owing to the anode purge occurred with an increase in the load current. Increasing the ambient pressure increased decay rate and recovery rate of the cell voltage, improved membrane hydration, and lowered the compressor power consumption. For the variable loads of the NEDC and WLTP, the fuel cell voltage and power fluctuated significantly. The membrane water content was controlled by the current in the low-current zone (i < 0.5 A cm-2) and was dominated by the high airflow in the high-current zone (i > 0.9 A cm-2). In the medium-current zone (0.5 A cm-2 < i < 0.9 A cm-2), the membrane water was saturated. The water vapor exhibited a dynamic behavior similar to that of the membrane water; the behavior fluctuated in low and high current zones and stabilized in the medium current zone. The liquid water fluctuated significantly in each current zone of the NEDC and WLTP. Additionally, the H2 utilization rates under NEDC and WLTP were greater than 99%. The developed global system model helps to understand the transient behaviors of a DEAmode PEMFC system and improves the system responsibility for fuel cell system design and development.