Initial assessment of component sizing and power-split for fuel cell hybrid electric heavy-duty trucks

Official URL: https://dx.doi.org/10.4271/2025-01-8550

This work presents a computationally inexpensive but effective method for an initial assessment of component sizing and power-split for fuel cell hybrid electric heavy-duty trucks. As a first step, the proposed method employs a prototypical longitudinal vehicle model to generate power demand at every instant of a representative drive cycle. Subsequently, six fuel cell and battery sizing combinations, each providing a peak continuous system power of 400 kW, are identified based on drive cycle power demands, commercially available fuel cell sizes, and Department of Energy (DOE) sizing targets. Ultimately, for each sizing combination, a proportional-integral (PI) controller with anti-windup is implemented to split power between the fuel cell and battery. In this study, the controller is tuned to reduce hydrogen consumption while meeting the instantaneous power demand and maintaining the battery state-of-charge (SOC) between 0.3 and 0.7. The results indicate that increasing the fuel cell size up to a certain threshold reduces hydrogen consumption, beyond which the trend reverses due to regenerative braking power limits and SOC sensitivity of the reduced battery size. This study finds that the combination with a 300 kW fuel cell and a 100 kW (50 kWh) battery achieves the lowest hydrogen consumption, yielding a fuel economy of 7.5 miles/kg, and attaining an 8.4% improvement over the least economical sizing combination.