Transient CFD Analysis of 1 kW Air-Cooled PEM Fuel Cell Stack During Startup

Start-up and variable load operation of a 1 kW air-cooled stack is investigated via computational fluid dynamics (CFD) analysis. The results of the transient analysis indicate that the temperatures inside the air-cooled stack are up to 27 °C higher when compared to the temperatures on the outside walls of the bipolar plates and this indicates a requirement for development of a new method for PEM fuel cell operation to increase the relative humidity of the reactants internally and prevent membrane dehydration. The novelty of this work is the method for increasing the relative humidity along the active area of the cell by intentionally increasing the pressure drop across the flow field, resulting in higher performance of the cell. The CFD model also investigates the influence of altering the bipolar plate material on the overall heat transfer inside the cell in order to achieve a similar effect with success in both cases