Numerical and experimental investigation on extreme optimization of thermal behavior for large-capacity battery modules with rear-inlet air cooling

Abstract

The performance and lifetime of batteries are significantly affected by temperature. Therefore, a novel airflow channel with synergistic cooling enhancement is proposed for typical rear-inlet air-cooled lithium iron phosphate (LFP) energy storage battery modules to explore the cooling mechanisms. Initially, considering the feasibility of structural adjustment, a novel rectification structure is proposed. Both simulations and experiments yield considerable improvements, demonstrating the rationality of optimization. Subsequently, two novel structures are proposed: harmonica pipe and heat exchange fin plate. Simulation studies show that among the three novel structures, the rectification structure can achieve the greatest improvement under any circumstances. The harmonica pipe and heat exchange fin plate structure exhibit their inherent superior heat exchange capabilities only when the rectification structure is present, revealing the enabling synergistic amplification effect of rectification structure on auxiliary structures. In addition, the optimal balance between the heat exchange area of the harmonica pipe and the wind speed is achieved, thereby maximizing the overall cooling effect. After extreme optimization, the cooling efficiency increases to 0.61 (64.9 %), and the maximum temperature rise decreases by 8.6 °C (36.9 %). Both temperature differences are less than 1 °C, with respective decreases of 5.4 °C (88.5 %) and 1.3 °C (56.5 %). The optimized flow channel achieves near extreme cooling efficiency and performance. Meanwhile, the cooling performance of final optimization is significantly improved under different ambient temperatures and charging rates, demonstrating its excellent universal applicability. The results of this study provide substantial and effective guidance not only for the rear air inlet method but also for other airflow methods and other domains such as the thermal management design of power batteries.