New criterion for achieving efficient flow fields in PEM fuel cells

Due to the needs of industries for clean and environmentally friendly fuels today, new energy sources such as fuel cells are at the center of attention. Polymer fuel cells, meanwhile, require a short start-up time due to low operating temperature, high power density, no emission and very low noise, making them the best option for vehicles as an alternative to internal combustion engines. One of the most important reasons for fuel cell loss is the uneven distribution of reactants on the active area, which causes non-uniform reactions. Therefore, the use of an optimal flow field to improve the durability and performance of PEM fuel cells seems necessary. Although different studies introduced novel designs, a study comparing different patterns comprehensively to introduce the best ones is not performed yet. In this study, first, a numerical validation was performed with an experimental test that showed good accuracy. Then, to achieve efficient patterns, several flow field designs were inspired by previous effective designs and others were selected as superior designs from the literature. The effects of presented geometries on the performance of a PEMFC were investigated to improve its performance. In addition, efficient evaluation criteria from the literature were employed to better analyze the performance of such systems, and the ones consistent with the I-V performance were introduced. By surveying the criteria, a novel performance factor was introduced that showed the best agreement with the I-V performance. The results were obtained in single-phase and two-phase approaches, which lead to remarkable findings. The two-phase study revealed that the waved serpentine case has the highest electrical performance with the highest mass fraction of oxygen.

Keywords:

PEM fuel cell , water management , gas flow field , Performance evaluation criteria