Multi-objective Optimization Study for Sizing and Optimal Control for an Integrated Fuel Cell-Battery System for Commercial Airliners

As the contribution of the global aviation industry to CO2 and non-CO2 emissions has been increasing at the rate of 4.5% per year, it has been raising an urgency in the industry for developing and implementing sustainable solutions to reduce the environmental impact and meet global climate goals. Standalone battery electric and hydrogen fuel cell systems though attracting significant attention as alternative sustainable aviation powertrains, the current state of these systems is still insufficient to meet the requirements of commercial missions. Hybrid fuel cell-battery powertrain systems, given the high specific power of fuel cells and the stronger dynamic performance of batteries, present a promising alternative for decarbonizing the aviation sector. However, integrating these systems into commercial aircraft requires precise sizing within operational volume and weight constraints and effective power distribution control to meet the varying power demands throughout the aircraft’s mission profile. While previous works have focused on mass minimised sizing for powertrain components in terms of maximum take-off weight limitations for an aircraft, differing volumetric densities of fuel cell and battery systems, compared to conventional propulsion systems, also necessitate careful component volume-sizing within the aircraft’s constrained fuselage and or wing volume. In this study, we aim to determine the optimum sizing for a hybrid fuel cell-battery system, using a multi-objective volume and mass optimization framework developed using Dymos and OpenMDAO, to meet the continuous power requirement profile for a commercial regional airliner. As a part of the project, optimization studies were performed for the propulsive power time series of the A320 aircraft for two operating ranges, 300 and 900 nautical miles, at different constraints for the battery and fuel-cell systems, like gravimetric efficiencies of the hydrogen storage tank, specific powers and volumetric power densities of the fuel cell stack, and volumetric and mass energy densities of the battery system. The study then provides a comparative analysis of the optimization results and evaluates the integrated powertrain system’s suitability, for different combinations of fuel cell and battery system properties, in terms of retained passenger capacity.

In AIAA SCITECH FORUM 2026