Better integrating battery and fuel cells in electric vehicles

Abstract

This paper presents an innovative approach to enhancing the range of battery electric vehicles (BEVs) through the integration of a hydrogen fuel cell range extender. By combining the high energy efficiency of BEVs with the rapid refueling capability and extended range of hydrogen fuel cells, this hybrid system addresses the limitations of current electric vehicles in scenarios demanding longer driving ranges or quicker refueling options. Our study encompasses both experimental and theoretical analyses, leading to the proposal of a BEV configuration that includes a smaller battery complemented by a fuel cell range extender. The conventional fuel cell electric vehicle (FCV) examined relies exclusively on hydrogen fuel and features a minimal battery without plug-in functionality, resulting in suboptimal energy economy. In contrast, our proposed BEV with a fuel cell range extender employs a larger battery capacity of 12 to 16 kWh alongside a downsized fuel cell stack and reduced hydrogen tank size. This configuration significantly improves energy recovery during braking and extends electric operation, thereby doubling the vehicle's energy economy. The proposed system not only enhances energy efficiency but also reduces the weight and volume of the overall energy storage system. Preliminary estimates suggest that the miles-per-gallon equivalent (MPGe) of this hybrid solution could exceed 140 over the US EPA certification cycle, outperforming existing PHEVs, BEVs, and FCVs.