The effects of different flow field patterns on polymer electrolyte membrane fuel cell performance

Abstract

The flow fields of bipolar plates are among the important factors that direct reaction, heat, pressure, and mass transfer by distributing the reactants on the electrode surfaces, and thus determine the cell's electrical performance. Hence, a convenient flow field distribution in polymer electrolyte membrane fuel cells (PEMFC) lowers both mass and charge transfer resistance, improves water discharge, and increases maximum power density. The serpentine flow field among different flow fields draws attention, but it is known that this design has some disadvantages such as high pressure drop. In this study, five flow fields were designed as an alternative to the serpentine flow field. The flow fields were had an active area of 50 cm2 and channel sizes of 1, 1.5, and 2 mm. The three-dimensional flow fields were simulated on the ANSYS software using computational fluid dynamics (CFD) method. Reaction heat source, temperature, pressure, mass fractions, and current density distributions were all taken into consideration in the analysis of the results. In addition, the electrical performances of different flow fields were compared on a polarization curve. The results demonstrated that Parallel M-type had the highest power density, whilst Stair type had the lowest power density. The Parallel M-type reached a current density of 1.31A/cm2 at 0.4 V and displayed a power density 7.4% higher than the serpentine flow field. In contrast to the serpentine flow field at 0.4 V, Parallel M-type also showed a 6.7% larger reaction area on the electrode surface, a 2% higher temperature value, a 62.7% lower pressure drop, a 17.1% higher current density, and heightened reactant activity.