Impedance as a Diagnostic Tool for Studying Fuel Cells
Friday, May 2, 2003 - 10:10am - 1:00pm
Daniel Baker (General Motors Corporation)
We will start by showing some CFD simulations of current distribution on a fuel cell. The current distribution behaves differently under different operating conditions and we will try to explain this behavior. This will lead us to consider impedance spectroscopy as a tool to investigate some of the critical effects that impact current distribution. A short explanation of impedance methods will be given along with a discussion of how to interpret impedance data in the context of current distribution. Special emphasis will be given to the high frequency resistance (HFR) as a tool for understanding membrane humidification. Other impedance applications include assessing proton resistance in the porous cathode, kinetic resistance of the cathode electrode, and the relative contribution of gas transport resistance to voltage losses.