Thermal Modelling of a Fuel Cell System for an Electric Vehicle

In the current global situation, organizations are required to achieve decarbonization. To reach this goal in the transportation field, one possible solution could be the electrification of vehicles. Fuel cells represent an optimal solution to pursue this goal. This dissertation aims at developing a thermal model of a Proton Exchange Membrane Fuel Cell in a Simulink environment that will be later integrated into the hybrid powertrain of a heavy-duty vehicle. Thermal management is crucial for a fuel cell system, particularly in automotive applications. In fact, during load variations, temperature changes impact negatively the efficiency of the fuel cell to the extent that at high temperatures the functioning can be irreversibly compromised. It has been implemented a lumped parameter approach for modeling the stack and the cooling system. The heat dissipated by the fuel cell allows to compute its temperature by solving the thermal circuit. To not overheat the fuel cell, a cooling system is integrated and it is composed mainly of pipes, a centrifugal pump and a radiator that releases a fraction of the heat into the surrounding environment. The model is tested in dynamic conditions through a driving cycle and it is validated using the results obtained in a Siemens software, namely AMESim. The outcomes show similar trends in temperature between the two models with low error on the estimated thermal behaviour.