MONITORING AN ELECTRODE FLOODING THROUGH THE BACK PRESSURE IN A PROTON EXCHANGE MEMBRANE (PEM) FUEL CELL

For proton exchange membrane (PEM) fuel cells, proper water management is important to obtain maximum performance. In understanding the water process within the fuel cell, the exhaust back pressure was found to be a useful indicator of the water content within the cell. Measured back pressure at the exhaust is an indication of how much water content is in the membrane during the electrochemical reaction. From these experiments, the measured back pressure shows when the fuel cell suffered from flooding because of generated water. When humidified inlet gases are supplied to the fuel cell, maintaining back pressure at the exhaust is an indication that the produced water is removed properly by the supplying gas. For the cases of dry operation, the average back pressure at the anode side continued to increase due to the back diffusion. This back diffusion was a result of the water concentration gradient between the anode and the cathode.