Multi-Material Topology Optimization of an Urban Air Mobility Vehicle Battery Pack

Urban air mobility (UAM) has been presented as an alternative form of transport for intra and inter-city travel in urban centers where there are significant limitations to ground travel due to traffic. Lithium-ion battery packs are used in these aircraft to provide power to the electric motors during both cruise and vertical takeoff and landing (VTOL). These battery packs contribute significantly to the overall weight of the UAM vehicle. Therefore, minimizing the mass of the battery packs contributes to the performance. The objective of this work is to create an optimized lightweight design for the battery pack housing while still meeting the structural requirements needed to protect the battery pack. A finite element model for the battery pack is used to determine the nodal forces applied on an individual battery module due to acceleration loads and the interactions with the other battery modules. Several different material combinations are tested and compared based on the minimization of both mass and compliance of the structure. Multi-material topology optimization is then performed on the individual battery module with the objective to minimize the compliance and mass of the structure subject to structural constraints. The optimized design is then evaluated using finite element analysis to ensure the structural, thermal, and material considerations are met. This work presents the final optimized design for the lightweight battery housing.