Numerical Modeling of the Proton Exchange Membrane Fuel Cell for Thermal Management

A thermal model of the Proton Exchange Membrane Fuel Cell (PEMFC) was developed to investigate the performance of a large active area fuel cell with the water cooling thermal management system. The model includes three sub-models: water transport model, electrochemical reaction model and heat transfer model. The water transport model calculates water distribution and the electric resistance of the membrane electrolyte. The electrochemical reaction model for the agglomerate structure cathode catalyst layer predicts the cathode overpotentials including mass transport limitation effect at high current density region. Two-dimensional heat transfer model incorporated with coolant and gas channels predicts the temperature distribution within the fuel cell. By integrating those sub-models, local electric resistance and overpotentials depending on the water and temperature distribution can be predicted. The model was calibrated with published experimental data and sensitivity studies were performed. The effects of the inlet gas temperature and humidity on the fuel cell performance were explored. In addition, the effect of the temperature distribution, and accordingly the electric resistance distribution within the fuel cell depending on the coolant temperature and flowrate was investigated. The results shows that the change in the local electric resistance due to temperature distribution eventually causes fuel cell power decrease and it is also concluded that the coolant temperature and flowrate should be controlled properly depending on the operating conditions in order to minimize the temperature distribution while maximizing power output of the fuel cell.