Design of a compact phase change material-integrated battery thermal management system for electric aircraft via topology optimization

Lithium-ion batteries in electric vertical takeoff and landing aircraft experience high and rapidly varying heat loads during power-intensive maneuvers. Cooling systems using phase-change materials provide valuable thermal buffering, but their poor thermal conductivity necessitates high-conductivity fins for effective heat removal. These fins must also add minimal mass, as thermal-management systems in electric aircraft are subject to strict weight constraints. This study introduces the first topology-optimization framework for transient heat conduction tailored to battery thermal-management systems in electric aircraft. Two representative aircraft configurations—Tilt-Wing and Lift-and-Cruise—are examined, and parametric studies quantify how phase-change-material and thermal-enhancer volume fractions, system size, and cooling boundaries shape optimized fin structures and their thermal performance. The optimal design maintains battery temperature below 41 °C under room-temperature and conservative natural convection while keeping the thermal-management-system mass below 33.3% of the battery-pack mass. Computational fluid dynamics simulations of selected designs show excellent agreement with topology-optimization predictions (≤ 1 K deviation), confirming that conduction-dominant optimization reliably captures the governing heat-transfer mechanisms. The framework enables lightweight, thermally efficient thermal-management solutions and offers a predictive design tool for next-generation electric aircraft.