Net Water Drag Coefficient during High Temperature Operation of Polymer Electrolyte Fuel Cells

Abstract

For polymer electrolyte fuel cell (PEFC) systems in vehicle applications, net water drag coefficient () is an essential index and must be negative for system operation. The feasibility of PEFC operation at temperatures over 100 °C was examined here by measuring and comparing the current density (j)— characteristics using PEFCs with either an Aquivion or Nafion membrane. The effect of cell temperature () on was evaluated at range from 80 °C to 120 °C. Results clearly demonstrated that, for both membrane types, significantly increased with increasing Results also confirmed that, at a constant flow rate of H2 at the anode, decreased with decreasing stoichiometric ratio of air (), although the effect of on was relatively small. Finally, the effect of relative humidity (RH) balance of supplied gases in both sides (anode/cathode) on water transport at temperature up to 120 °C was examined for the Aquivion cell. Results revealed that could be significantly decreased by decreasing the RH of hydrogen supplied to the anode (RHA) and that the control of RHA is an effective method for lowering at elevated temperature operation.