Thermal modeling of the proton exchange membrane fuel cell

This dissertation presents a systematic approach for the study of the performance of the proton exchange membrane fuel cell (PEMFC). This work includes two simulation models: a comprehensive multi-dimensional thermal model and a lumped transient model of the PEMFC system.;The comprehensive multi-dimensional thermal model has been developed to study the performance of the large active area unit PEMFC with a water-cooled thermal management system. The comprehensive multi-dimensional thermal model has three sub models to capture the multidisciplinary physics of the PEMFC: a water transport model in the membrane electrolyte for the electric resistance, an agglomerate structure electrochemical reaction model for the cathode overpotentials, and a two-dimensional heat transfer model for the thermal management. A sensitivity study shows that the performance of the PEMFC changes with the inlet gas stoichiometry flow rate, the inlet gas humidity and temperature, and the degree of the temperature distribution on the fuel cell.;A lumped transient system model has been developed for the system level study. The model includes the transient PEMFC stack model and the transient cooling system model. A systematic approach has been suggested to boost the analysis capability via combination of two simulation models. The thermal management criteria have been determined by the unit PEMFC model. First, a proper fuel cell operating temperature was determined considering the durability and the safety margin during transient operation. Second, the temperature distribution on the fuel cell has been optimized to achieve higher performance with lower parasitic loss of the cooling pump. As a part of the systematic approach, the lumped transient system model has been used to determine the proper control algorithms to support the thermal management strategy. A feedback control algorithm has been compared to the conventional on/off control algorithm. The result shows that the feedback control algorithm is more efficient than the conventional control algorithm for the reduction of parasitic loss in the thermal management system. Moreover, the feedback control algorithm with the thermal management strategy also improves the net power of the PEMFC system.