Effect of finned networks on PCM based battery thermal management system for cylindrical Li-ion batteries

The present numerical work investigates the effect of finned structures on the passive thermal management of cylindrical Lithium-ion batteries. Novel hexagonal thermal conduction networks using metal fins are proposed. The electrochemical-thermal coupling for the numerical modeling is achieved using the Newman-Tiedemann-Gu-Kim (NTGK) semi-empirical method extended with the enthalpy model to incorporate phase change materials. Firstly, the effect of the different structures on the thermal behavior and the delivered capacity for a high discharge rate of 4 C is analyzed. The addition of base PCM (phase change materials) decreases the overall increase in temperature by about 71.9 %, and up to 75.58% for the optimal thermal conduction network. The finned structures also show more temperature uniformity in the battery module. Next, the effect of the ambient temperature on the thermal performance of the proposed designs is shown. Further, the behavior of the enhanced system is studied under a stressed discharge rate of 6 C and an abuse discharge rate of 8 C. The study is further extended to examine the viability of the proposed battery thermal management system (BTMS) when the cell arrangement is externally shorted with a small resistance of 0.5 ohm. Based on the numerical analysis the proposed designs perform well.