System-Level Implications of Fast Battery Charging During the Turnaround of Hybrid-Electric Aircraft

High aircraft utilization is essential for economically viable operation, making turnaround time an important metric. For hybrid-electric aircraft, battery charging forms part of the turnaround process and may become a design driver when the available charging time is limited. This study investigates this challenge by integrating an electrical battery model with a heat-generation model into an iterative aircraft design framework to account for turnaround-driven charging requirements in battery sizing and aircraft design. Charging time and battery heat generation are determined from battery-cell characteristics and operational boundary conditions and linked to the in-flight energy and power requirements. The results show that a battery sized only according to the in-flight energy and discharge-power requirements has a charging time of approximately 90min under the reference assumptions. Reducing the effective charging time to 25min requires a maximum charging rate of approximately 2.7 A/Ah. Charging-constrained sizing shifts the battery design toward higher mass-specific power and lower mass-specific energy, increasing aircraft mass and reducing the energy-specific air range by up to approximately 5%. In addition, battery heat generation during charging can exceed 20 times the maximum in-flight battery heat load. Fast charging should therefore be treated as an aircraft-sizing constraint and jointly considered in preliminary aircraft design, turnaround planning, thermal management, and airport infrastructure considerations.