Investigation of bipolar plate geometry on direct methanol fuel cell performance

The effect of bipolar plate (BPP) channel width on the performance of a single-cell direct methanol fuel cell (DMFC) stack was investigated. Three BPPs with a single-channel serpentine configuration were fabricated with three different channel widths having the same effective flow areas. Experimental tests showed that the fuel cell with the narrowest channel width had the best overall performance while the one with the widest channel width had the worst overall performance. A computational fluid dynamics (CFD) model was developed and simulated to investigate and understand the reasons for this change in performance. The CFD simulation showed that in the narrower channel the diffusion of the fuel within the diffusion layer was higher and the fuel distribution was more uniform. However, the pressure drop across the inlet and outlet was higher in the narrower channel, which increased the pumping power requirements.