Definition of The Optimal Battery Capacity of a Fuel Cell Vehicle

The polymer electrolyte membrane fuel cell system is subject to dynamic requirements in mobile applications in vehicles, which are in conflict with the lifetime of the fuel cell. Therefore, a battery is installed as an electrical intermediate storage for the operation of the system. An iterative inversion was performed to determine the optimal capacity of this battery and to derivate the dynamic requirements of the PEM fuel cell. For this purpose, a reference vehicle with polymer electrolyte membrane fuel cell was implemented in the simulation environment Matlab / Simulink. The model is based on a PEM fuel cell model, which describes the physical and electrochemical interactions within the cell. In the next step this model was integrated into a complete vehicle model, whose parameters within the simulation model were adjusted according to the comparison vehicle. The legal driving cycles NEDC (“New European Driving Cycle”) and WLTP (“Worldwide harmonized Light Vehicles Test Procedure”) were used for the calculation. The ascertained and evaluated data sets provide information about the maximum and minimum required battery capacity of a fuel cell vehicle system while stationary and dynamic operation. In the future, the dynamic requirements – for the fuel cell and the associated system components – can be scaled generically for any vehicle taking into account the battery capacity with the simulation model.