Integrated Analysis of Electric Aircraft Performance and Battery Design Through Coupled Modeling of Flight, Battery, and Thermal Dynamics

Abstract

Electronic Thesis or DissertationElectric aviation has emerged as a focus of research in recent years with significant progress in electric aircraft development. One of the greatest hinderances to the wider adoption of electric aircraft is the inability of current battery technology to simultaneously provide high gravimetric energy density and power density over a wide range of operating conditions while ensuring safety and reliability. In this work, a coupled framework consisting of longitudinal flight dynamics for a fixed-wing aircraft, high-fidelity electrochemical battery physics, and battery heat generation is developed to analyze battery performance characteristics and understand performance limitations under dynamic loads representative of an aircraft propulsion system. Using this framework, simulations are conducted to analyze and understand the interplay between electrode design parameters and material properties, flight control variables, and operating temperature of the battery system. The results show that cruise velocity has the largest impact on the aircraft range with the range 30% higher at the optimal velocity compared to the lowest range at highest cruise velocity considered. The range and cell-level limiting current are found to drop by as much as 15% and 50% at 0°C compared to their respective values at 30°C. For the range of values considered, electrode design parameters have been found to increase the aircraft range and the limiting current by approximately 15% and 150%, respectively, compared to the reference design parameters values representative of actual cell considered in this study. After taking into account all the key energy loses occurring at the cell level, we found each kWh of pack energy to translate to about 6.5km of air travel distance. Additionally, battery heat generation modeling was incorporated and compared to experimental data. Peak battery temperature during the climb phase vary between 7 and 20°C depending on ambient temperature, the amount of cooling, power requirement, and battery electrode design. Finally, atmospheric variations' effect on air density and battery performance are analyzed leading to aircraft range differences of up to 21% between locations at the same time of year and up to 11% at the same location at different times of year