Understanding the Interplay of Battery and Flight Dynamics Using Coupled Battery and Flight Physics Simulations for Electric Aircraft

Abstract

Electric aviation has been a major focus of research in recent years as the aviation industry has seen significant growth in electric aircraft development. Most of the current literature related to electric aircraft modeling focuses on aircraft design and optimization with less focus given to battery analysis. Many studies utilize battery simplifications such as linear voltage profiles1 or the use of equivalent circuit models2. Similarly, in the emerging field of electric vertical takeoff and landing (eVTOL) aircraft, battery analysis is often reduced to considering just weight and empirical power parameters, failing to capture physical and electrochemical battery behavior and its effect on battery performance characteristics3. These simplifications can often lead to inaccurate battery state estimations and performance prediction. Moreover, the battery packs used for both electric conventional take-off and landing (eCTOL) aircraft and eVTOLs see unique operating requirements that are often significantly more demanding than those seen in electric vehicles (EVs)4. This suggests the need to analyze aircraft battery pack performance limitations in greater detail. However, only a few such studies have been reported in the literature5-6.In this work, we perform coupled simulation studies of longitudinal flight dynamics and physics-based battery dynamics. For modeling battery dynamics, we use the well-known single particle model7. This coupling enables more reliable estimation of battery states and can better inform battery pack design for electric aircraft. The simulations are performed to understand the interplay between battery cell dynamics governed by its design parameters and parameters associated with fixed-wing flight dynamics, such as cruise altitude, flight path angle, and velocity. Additionally, the simulations show how varying these parameters and operating temperature effects the range and endurance of electric aircraft which can be used to determine the optimal aircraft operating parameters for a desired mission profile. Results from this simulation study are compared against an equivalent circuit battery model to highlight the importance of detailed battery analysis in electric aviation. This work will be extended to develop similar coupled physics-based battery models with the state-of-the-art aircraft configurations emerging in the eVTOL field.References M. Kaptsov and L. Rodrigues, Journal of Guidance, Control, and Dynamics, 41, 288 (2018).N. Biju and H. Fang, Applied Energy, 339, 120905 (2023).L. Kiesewetter, K. H. Shakib, P. Singh, M. Rahman, B. Khandelwal, S. Kumar and K. Shah, Progress in Aerospace Sciences, 142, 100949 (2023).X.-G. Yang, T. Liu, S. Ge, E. Rountree and C.-Y. Wang, Joule, 5, 1644 (2021).A. Ayyaswamy, B. S. Vishnugopi and P. P. Mukherjee, Joule, 7, 2016 (2023).M. Wang, S. Kolluri, K. Shah, V. R. Subramanian and M. Mesbahi, IEEE Transactions on Aerospace and Electronic Systems, 59, 1084 (2022).S. Santhanagopalan, Q. Guo, P. Ramadass and R. E. White, Journal of power sources, 156, 620 (2006).