Topology-Optimized Indirect Cooling System for Thermal Management of Cylindrical Li-Ion Battery Packs

This study introduces an innovative thermal management system for cylindrical Li-ion battery packs, designed to control temperature rise during standard operation while maintaining a uniform temperature distribution. The proposed system employs an indirect cooling approach, utilizing channels that circulate water as the heat transfer fluid. These channels are thermally coupled to the batteries via an aluminium cold plate, which serves as both thermal spreader and structural support. Notably, the metal support integrates the cooling channels without direct battery contact, serving as conductive path for heat dissipation. The analysis focuses on a Sony 18650 cylindrical battery, with a nominal capacity of 2.7 Ah and a voltage of 3.6 V. Heat transfer performance is evaluated using Bernardi's thermal model at a C-rate of 10. To address the high weight of the metallic cold plate, a topology optimization (TO) approach is implemented to identify the material distribution that allows the battery to effectively dissipate thermal power into the heat transfer fluid while reducing the system's weight. This redesigned component achieves an 80% weight reduction compared to the baseline metal spreader, with a minimal trade-off of a 1°C increase in temperature rise. The results underscore the potential of topology optimization to generate practical designs that facilitate efficient battery thermal management systems.