  A persistent challenge with the development of electric vertical take-off and
landing vehicles (eVTOL) to meet flight power and energy demands is the mass of
the load and thermal management systems for batteries. One possible strategy to
overcome this problem is to employ optimization techniques to obtain a
lightweight battery pack while satisfying structural and thermal requirements.
In this work, a structural battery pack with high-energy-density cylindrical
cells is optimized using the level-set topology optimization method. The heat
generated by the batteries is predicted using a high-fidelity electrochemical
model for a given eVTOL flight profile. The worst-case scenario for the
battery's heat generation is then considered as a source term in the weakly
coupled steady-state thermomechanical finite element model used for
optimization. The objective of the optimization problem is to minimize the
weighted sum of thermal compliance and structural compliance subjected to a
volume constraint. The methodology is demonstrated with numerical examples for
different sets of weights. The optimized results due to different weights are
compared, discussed, and evaluated with thermal and structural performance
indicators. The optimized pack topologies are subjected to a transient thermal
finite element analysis to assess the battery pack's thermal response.
