Fuel Cell-Battery Hybrid Calculator for Initial Assessment of Component Sizing and Power-Split

Fuel cell-battery hybrid powertrains could provide a sustainable alternative to conventional internal combustion engine powertrains for several automotive applications. However, their total cost of ownership based on their upfront capital costs, operational costs, and component degradation costs should be thoroughly investigated before adopting them for a given application. Determining these costs is a problem directly dependent on the component sizes picked and the power-split strategy applied. Hence, this work presents a simple calculator that provides approximate component sizes and an associated power-split strategy for an initial assessment of the total cost of ownership based on user-defined inputs. At the minimum, these inputs are a drive cycle, longitudinal vehicle parameters, and an expected vehicle lifespan but the user could also define the fuel cell and battery plant parameters. The proposed calculator, based on the user’s selection from a library of drive cycles, determines all feasible combinations of fuel cell and battery sizes. Subsequently, for each sizing combination, the total cost of ownership over the vehicle’s lifespan is minimized by computing optimal gains for a SOC-maintaining PI controller. Ultimately, the sizing combination with the lowest total cost of ownership and its associated controller gains are provided as primary outputs from the calculator. The calculator also provides additional information regarding the weight and volume implications of the optimal sizing combination, further aiding the feasibility assessment. To evaluate the effectiveness of the calculator, an example sizing exercise for a heavy-duty truck is carried out for different sets of user-defined inputs and the results are discussed. Lastly, the implementation of the calculator is open-source, enabling vehicle owners and small businesses to make an initial assessment of transitioning to a fuel-cell hybrid powertrain.