This section contains work related to the modeling of voltage degradation in a 24 cell PEM fuel cell stack with 300 cm2 cross-sectional area. The experimental hardware used to validate the model consists of a computer controlled system that coordinates air, hydrogen, cooling, and electrical subsystems to operate the stack. Dry hydrogen is pressure regulated for full utilization in the dead ended anode. Using a solenoid valve, the anode is periodically purged to recover the gradual degradation in voltage. A membrane based humidifier controls the vapor content of the cathode gas stream while a mass flow controller is used to regulate the flow to a desired stoichiometry. A schematic of the experimental setup is shown below.
The average voltage of the experimentally measured 24 individual cells is used to calibrate the model output voltage. The estimated cell voltage was bounded by the maximum and minimum individual cell voltages during all experiments, and the measured cell to cell variation was larger than the average estimation error.
A publication featuring this model can be found in the Journal of Power Sources. See the ‘Publications’ tab for a full citation.