On the Trade‐Off between Battery Size and Sustainability for a Fuel Cell Hybrid Electric Vehicle

Fuel cell vehicles (FCVs) offer a promising route to decarbonization of the transport sector. Since all FCVs benefit from hybridization with a small battery pack, understanding the impact and limitations of the fuel cell and battery sizing regarding the vehicle's energy efficiency and environmental aspects is needed to support the development of these technologies. Herein, fuel cell hybrid vehicles with different battery sizes concerning the impact on energy efficiency and carbon emissions for three different drive cycles are investigated. Results suggest that increasing the battery capacity (up to 5 kWh) can considerably lower the hydrogen consumption. The fuel consumption saving can balance the carbon emissions for the extra battery size, up to 50 000 km driven, if gray hydrogen is used as a fuel. In the case of green hydrogen fuel, the extra battery size is mostly justified only if speed‐aggressive driving is frequently used and/or if the green hydrogen production generates close to 5 kg‐CO 2 /kg‐H 2 .