Prediction and experimental validation of in-plane current distribution between channel and land in a PEFC

A nonisothermal, two-phase model for polymer electrolyte fuel cells is validated against the experimental data of in-plane current density profiles. Overall, good agreement is achieved between predicted and measured current density distributions between the channel and land with submillimeter resolution. Numerical simulations clearly show that the in-plane current profile results from the interplay between the ohmic control and mass transport control, both of which depend strongly on the two-phase water transport along the in-plane direction. Under relatively dry and large stoichiometric conditions, the current density peak is seen to shift from under the land to under the channel with increasing average current density, signifying control by membrane resistance at low current densities but by oxygen diffusion at high current densities. Finally, the validated model reveals the dramatic influence of the channel/land width and gas diffusion layer compression on the in-plane current density profile, thus underscoring the necessity to match these two key parameters in experimental measurements of in-plane current distribution. (c) 2007 The Electrochemical Society.