Sensitivity analysis of operating parameters on a 65 kW proton exchange membrane fuel cell stack performances

Abstract

It is widely acknowledged that the operating parameters of fuel cell stack have significant influences on the output performances. However, there is still a lack of relevant research on the parameter sensitivity test for high-power vehicular stacks. In the study, the orthogonal test method is adopted for a 65 kW fuel cell stack. Effects of operating temperature, relative humidity, stoichiometric ratio, and inlet pressure are quantitatively investigated. It is found that the stack voltage increases significantly when the operating temperature rises from 60 °C to 70 °C while no remarkable performance differences are observed when the temperature further rises from 75 °C to 80 °C. With the increase of reactant relative humidity, the change of voltage change ratio is more obvious in the low current density regions. It is also inferred that the stack performance enhancement caused by better hydration level will be less effective once the inlet relative humidity reaches a certain degree. Increasing the inlet reactant pressure promotes the mass transfer capacity. Besides, the performance is improved more significantly in the high current density regions, which may be attributed to the improvement of concentration polarization. When the stoichiometric ratio increases, the stack output voltage does not increase significantly at lower current regions, but there exists significant performance optimization at higher current regions. The paper contributes to the deeper understanding of transport phenomena as well as better performance enhancement suggestions for vehicular fuel cell stacks.