Implementation and evaluation for anode purging of a fuel cell based on nitrogen concentration

When a proton exchange membrane fuel cell is operated in a dead-ended anode mode, its performance gradually decreases due to accumulation of nitrogen and liquid water. Many experimental studies show that nitrogen accumulation is mainly responsible for the performance drop. In this study, a dynamic mathematical model developed in our previous work is employed to predict the nitrogen accumulation in the anode and its corresponding cell voltage. The model is calibrated and validated using experimental data. A purge strategy based on nitrogen concentration in the anode is developed by the calibrated model and implemented into the controller for anode gas management. The performance variations of the single cell operated at a varying-current condition and purged at three nitrogen molar fractions are compared and discussed. Results show that simulated voltage variation agrees with experimental data. When the anode is purged at the nitrogen molar fraction of 0.15, the cell performance shows a dramatic variation. At the end of this study, anode purge based on current-integration with time is also evaluated. (C) 2013 Elsevier Ltd. All rights reserved.