Performance enhancement of fuel cells using bipolar plate duct indentations

In this paper, a method called “bipolar plate duct indentation” is introduced, in which some partial blocks (indents) are recommended to be placed along the fluid delivery channels being machined in bipolar plates (BPPs) of fuel cells (FCs). The indents are to enhance the over-rib convections and the kinetics of reactions in catalyst layers to improve the cell performance. As an initial step to numerically model this problem, a partially porous channel of BPP of a Direct Methanol FC (DMFC) is taken as the model geometry, and the level of heat exchange enhancement due to channel indentation is examined in this geometry. The performed parametric studies show that channel indentation enhances the heat exchange by 40%; with some minor increases in fluid delivery pumping power. From the analogy between the heat and mass transfer problems in dynamically similar problems, it is believed that the mass exchanges between the core channel and the catalyst layer in FC will enhance the same order as that in the pure heat transfer problem. The present work provides helpful guidelines to the bipolar plate manufactures of low-temperature FCs to considerably alleviate the losses on the side(s) of slow reaction electrodes.