Two-Dimensional Property Distributions, Ohmic Losses, and Power Consumption within a Fuel Cell Polymer Electrolyte Membrane

The average and localized water content, current, ohmic loss, and power consumption distributions within a Nafion 117 polymer electrolyte membrane (PEM) were modeled in two dimensions to determine the influence of the cathodic flowfield plate on the properties and performance of a fuel cell. The membrane model was decoupled from the cathode and anode by using fixed, assumed anodic boundary conditions and cathodic boundary conditions from literature indicative of operation at three channel:land configurations (1:1, 2:1, and 4:1) and three nominal cathode overpotentials (NCOs) (0.3, 0.5, and 0.7 V). The results suggested that a 1:1 configuration maintained the membrane in a more-hydrated state that was better able to moderate changes in ohmic loss and power consumption due to changes in the NCO. Detailed distributions within the membrane showed complex anisotropy, including the existence of localized maxima along anodic boundaries, cathodic boundaries, and even along both anodic and cathodic boundaries under the same operating conditions.