Operation-relevant modeling of an experimental proton exchange membrane fuel cell

A current–voltage (I–V) curve, also known as a polarization curve, is generally used to express the characteristics of a proton exchange membrane (PEM) fuel cell system. The behavior of a PEM fuel cell is highly nonlinear and it is important to incorporate process nonlinearity for control system design and process optimization. Therefore, it is essential to generate the I–V curve from the model as the operating condition changes. A first principle one-dimensional water and thermal management model is developed to generate the I–V curve. The model considers the effects of water transport across the membrane, activation overpotential, ohmic overpotential, concentration overpotential, pressure drops, and current density distribution along the channel of a PEM fuel cell. Design and modeling parameters are obtained via regression from four sets of experimental data. They are further validated as operating conditions (e.g., fuel cell temperature, anode pressure, cathode pressure, hydrogen stoichiometric ratio, air stoichiometric ratio, hydrogen humidification temperature, and air humidification temperature) change. A sensitivity analysis example is used to illustrate the usefulness of the predictive model.