Computational modeling of PEM fuel cells with PBI membranes

A parametric model of a proton exchange membrane fuel cell (PEMFC) operating with a polybenzimidazole (PBI) membrane is presented. The model is three dimensional and applicable for PEMFCs operating,at intermediate temperatures (120-150 degrees C). It accounts for all transport and polarization phenomena, and the results compare well with published experimental data for equivalent operating conditions. Results for oxygen concentration and temperature variations are presented. The model predicts the oxygen depletion, which occurs in the catalyst area under the fibs, and which gives an indication of the catalyst utilization. Results also predict that for an output power density of 1 kW m(-2), a cell temperature rise of up to 30 K can be expected for typical laboratory operating conditions. Parametric analyses indicate that significant gain in fuel cell performance can be expected by increasing the conductivity of the PBI membrane. Further, results demonstrate that when the catalyst region is well utilized, increasing the catalyst activity results in only a small improvement in performance.