Impact of metallic bipolar plates on cold-start behaviors of Polymer Electrolyte Fuel Cells (PEFCs)

To meet the target of DOE for bipolar plate, a metallic bipolar plate has been considered as a replacement for a conventional graphite bipolar plate for automotive fuel cells mainly owing to its cheaper fabrication cost. In this work, a multi-dimensional, multi-phase, transient cold-start fuel cell model is applied to polymer electrolyte fuel cell (PEFC) geometries with metallic bipolar plate (BP) and conventional graphite BP to precisely examine the effect of metallic BP on cold-start behaviors of PEFC. The cold-start model predictions indicate that different cold-start behaviors between metallic BP and graphite BP based fuel cells indeed exist and emphasize that using metallic BP improves fuel cell cold-start performance by increasing the cell temperature more quickly during cold-start. ► We studied cold-start behaviors of metallic and graphite BP based PEFCs. ► Use of metallic BP is beneficial to improve PEFC cold-start performance. ► Ice growth rate in the metallic BP is prevented and effectively suppressed. ► Graphite based fuel cell failed to start up because of its large thermal mass. ► Cold-start situation is worsened by the presence of coolant in the cooling channels.