Electrical Contact Resistance Between Gas Diffusion Layers and Bipolar Plates for Applications to PEM Fuel Cells

The electrical contact resistance between gas diffusion layers and bi-polar flow channel plates is one of the important factors contributing to the operational voltage loss in fuel cells. Effective analysis and design of fuel cells therefore need to account for the contact resistance in deriving the polarization curve for the cell. Despite its significance, relatively scant work is reported in the open literature on the measurement and modeling of the contact resistance in fuel cell systems, and the present work aims to fill this void. Experimental data are reported for the first time to show the effects of different gas diffusion layer materials and contact pressure on the electrical contact resistance. A fractal asperity based model is adopted to predict the contact resistance as a function of pressure, material properties, and surface geometry. Good agreement is observed between the data and the model predictions for a wide range of contacting pressures and materials.