Numerical Simulation of the Thermal Behavior of a Lithium-ion Cell Pack with Various Thermal Dissipation Structure and the Addition of Phase Change Materials

Abstract

This study presents a transformative approach to passive thermal management in lithium iron phosphate (LiFePO₄) battery packs through geometrically optimized aluminum cooling structures. We investigate four distinct configurations - baseline (uncooled), unilateral side plate, inter-cell plates, and molded enclosure using experimentally validated COMSOL Multiphysics simulations under extreme 20C discharge conditions (50 A per cell). The most advanced design, featuring an aluminum mold surrounding 90% of each cell's height, achieves an unprecedented 11 °C reduction in peak temperature (from 66 °C to 55 °C) compared to conventional uncooled packs, while maintaining 99.1% of original power output (1107 W vs. 1118 W). This performance surpasses existing passive cooling methods and rivals many active systems, accomplished through three key innovations: 1. a patented snap-fit aluminum geometry that enhances heat transfer while simplifying assembly, 2. strategic material distribution that reduces thermal gradients by 32% compared to baseline, and 3. a cost-effective solution adding less than $1 per pack in material expenses. Furthermore, when combined with paraffin phase change material, the system demonstrates additional thermal buffering capacity, delaying critical temperature thresholds by 4.2 minutes during overload conditions. These findings provide battery designers with validated, scalable solutions that address the critical trade-offs between cooling performance, power output, and manufacturing complexity in next-generation energy storage systems.