Thermal management and cycle life enhancement of Lithium-ion Battery packs using low-fin tubes: Electrochemical-thermal-aging modelling and geometric optimization

Air cooling remains the most widely adopted thermal management strategy for lithium battery packs due to its simplicity and reliability. Thus, improving cooling efficiency and temperature homogeneity remains critical for such methods. Herein, this study proposes a low fin tube (LFT) enhanced air-cooling strategy, where the aluminum tubes with integral low-profile external fins serve as extended heat exchange surfaces around cylindrical cells. A lumped battery electrochemical-thermal-aging model was developed in COMSOL Multiphysics environment and validated with the experimental data. Subsequently, the baseline LFT geometry was evaluated and optimized through a systematic parametric study to achieve an ideal balance between thermal performance and system weight. An optimized configuration was identified, realizing a mass reduction of 6 g and an energy density increment of 10.6 Wh/kg. It was found that the optimized LFT reduced the required volumetric flow rate by 42.7% compared to direct cooling while maintaining temperatures below 40 °C at 4C. At the pack level, the LFT system significantly enhances thermal uniformity during 3C discharge-charge cycle, lowering the maximum pack temperature by 9.1 °C and reducing the temperature difference by 7.2 °C. Furthermore, LFT retains a 0.6% higher SOH after 50 cycles than direct cooling, and such retention advantage becomes more significant with cyclic operation.