Flow field plates with trap-shape channels to enhance power density of polymer electrolyte membrane fuel cells

Power density of proton exchange membrane fuel cells (PEMFCs) can be enhanced by optimal design of the shape and dimensions of bipolar plate channels. By introducing a novel, trap-shape channel design, the present work investigates the impact of having smaller land widths at different cross-sections of each bipolar plate on the PEMFC performance. The possible capabilities of this trap-form channel are investigated through a three-dimensional non-isothermal model in ANSYS Fluent. It is found that having narrower lands at a number of plate cross-sections enhances the current density per unit active area. However, there are critical (optimum) values for both length and number of these traps where the PEMFC performance is maximized. The results show that channels with two 8-mm-long traps provide considerably higher current densities. These two-trap channels also improve the distribution of oxygen and water over the cathode catalyst, which consequently results in less cathodic overpotential across the cell. As a result, the proposed trap-shape channel significantly enhances the power density while being as simple and inexpensive as the conventional/classical straight (no-trap) channels for fabrication. This new, trap shape of channels can therefore be considered one of the promising channel designs for the next generation of PEMFCs. (C) 2018 Elsevier Ltd. All rights reserved.