Performance improvement of proton exchange membrane fuel cell stack by dual-path hydrogen supply

Abstract

Proton exchange fuel cell stack typically operates in dead-ended anode mode to achieve high fuel utilization, but this can cause issues such as flooding and fuel starvation. To mitigate these problems, this study proposes a dual-path hydrogen supply strategy with simultaneous isostatic hydrogen supply from the stack inlet and outlet. When applied in a water-cooled stack containing 20 single cells, the split ratio of the two branches is maintained at about 1.0, which means that hydrogen supplied from the two paths is equal. Both dead-ended anode mode and dual-path hydrogen supply mode are tested under two different cathode back-pressure conditions to verify the effectiveness of the proposed strategy, and parameters such as pressure drop, voltage change, and fuel utilization are discussed in detail. Results show that the proposed strategy provides more hydrogen downstream of anode flow channels and promotes water redistribution, thus effectively improving the stack performance. Compared with dead-ended anode mode, dual-path hydrogen supply mode increases the stack voltage by 4.28% at 0.9 A/cm2. Furthermore, the effect of different purge periods is also probed on the proposed strategy.