Modeling and optimization of power battery for hybrid aircraft

Abstract

Aiming at the dual requirements of modeling accuracy and computational efficiency for power battery systems in the conceptual design of hybrid electric aircraft (HEA), this paper proposes a system-level trade-off-oriented battery modeling and design framework. Firstly, a grey-box equivalent circuit model (ECM) with physical interpretability and computational robustness is established based on rate discharge experimental data of Molicel high-performance cells. The model adopts nonlinear charge transfer and first-order diffusion dynamics to accurately capture polarization voltage drop under high discharge rates. Subsequently, a continuous battery family surrogate model is constructed via piecewise cubic Hermite interpolation (PCHIP) and multi-cell convex combination, expanding the energy-power trade-off design space. This paper integrates a dynamic mass evaluation model into mission profile analysis and reveals the switching mechanism between power-limited and energy-limited conditions by comparing competitive battery mass constraints in different mission segments. The results verify that the proposed method can effectively support rapid type selection and scheme decision-making of propulsion systems for hybrid electric aircraft.