Dynamic topology optimization of battery packs for eVTOL aircraft under time-dependent loading

View Video Presentation: https://doi.org/10.2514/6.2021-3068.vid Electric air taxis are envisioned to enable a new form of aviation in dense, urban locations. One of the feasibility barriers is the limited range due to the much lower energy densities that batteries have compared to fuel. A promising research direction to overcome this bottleneck is the use of multi-functional battery packs that dissipate heat but also carry structural loads. Here, we propose a scalable approach with automated derivative computation to design a battery pack of an eVTOL aircraft considering the power profile in takeoff, which is presumed to be the sizing condition. The problem uses a multi-fidelity submodel consisting of an equivalent circuit model to represent battery cells and a high-fidelity dynamic thermoelastic submodel of the battery pack. First, a steady-state topology optimization problem is solved based on the maximum heat output of the battery cells, computed from the aircraft power profile. Second, a dynamic topology optimization problem is solved based on the transient portion of the transition from liftoff to forward flight. Compared to the steady-state topology optimization, a 9.94% reduction in time-averaged compliance is obtained with the dynamic topology optimization.