Hydrogen starvation mitigation strategies during the start-up of proton exchange membrane fuel cell stack

Hydrogen starvation during start-up loading and rapid load change is a severe threat to the life and durability of proton exchange membrane fuel cell. To mitigate and eliminate hydrogen starvation during start-up loading, a dual-path hydrogen supply strategy is proposed to improve hydrogen diffusion within the stack. Based on constant loading rate continuous loading, two optimized start-up strategies with variable loading rates are presented. Stack voltage, stack average temperature, and single-cell temperature uniformity under different start-up loading strategies are discussed in detail. Experimental results show that at the end of continuous loading with a loading rate of 0.67 A/s, the peak voltage uniformity rate of dual-path hydrogen supply mode is 12.67% lower than that of dead-ended anode mode. In start-up loading from open-circuit state (0 A) to nominal state (40 A), single-cell temperature uniformity index has a maximum reduction of 0.136 °C compared to dead-ended anode mode. Besides, the combination of dual-path hydrogen supply and gradual-decreasing loading rate eliminates voltage overshoot during start-up loading, and reduces the single-cell temperature uniformity index by a maximum of 15.8%. Results indicate that the proposed strategies can mitigate hydrogen starvation, and improve the stability of stack voltage and the temperature uniformity of single cells.