Transient response modeling of reactant concentration in polymer electrolyte membrane fuel cells during load change

This paper outlines a semi-empirical model to account for the transient response of Polymer Electrolyte Membrane Fuel Cells (PEMFC) during load changes. In this work, we investigated the voltage undershoots of the PEMFC system with a current step-up given as the input. The dynamic response of PEMFC during stepwise load changes is a vital factor that indicates cell performance. We present a model based on mass balance equations, various transport phenomena, and experimental conditions for these voltage undershoots. This model's response highlights the impact of reactant starvation inside the fuel cell stack during step increase in current. A single fuel cell is divided into two domains to analyze the availability of reactant gases. The model can anticipate the impact of different operating conditions on the magnitude of voltage undershoots. Validation of the model with experimental data resulted in a maximum relative error of 4.59%, with the goodness of fit in the range of 0.96 to 0.99, making the model statistically significant.