Experimental and numerical investigation of the effect of forced air-cooling parameters on temperature distribution at lithium-ion battery module

Abstract The air-cooling system is an advantageous cooling method for battery modules due to its low cost, light weight, simple design, and no sealing required. In this study, the thermal performance of an air-cooled lithium-ion battery module was investigated through both numerical and experimental approaches, considering the influence of various design and operating parameters. The experimental investigation was conducted to examine the thermal behavior of an air-cooled lithium-ion battery module under specific operating conditions, providing temperature distribution data to validate the numerical model. Distinguishing itself from previous studies, this research replaces simplified assumptions with a high-accuracy approach by employing the mesh motion technique for dynamic airflow generation and an Equivalent Circuit Model (ECM) validated with experimental HPPC data. After the numerical model was validated against experimental data in terms of battery cell temperature, demonstrating high statistical reliability with an average R 2 of 0.979, comprehensive numerical analyses were conducted to investigate the effects of six critical design and operating parameters: fan speed, ambient temperature, discharge rate, air outlet and fan positions, and inter-cell spacing. The battery cells’ temperature inside the module decreased as the fan speed increased up to 4000 rpm, but no significant change in temperature was observed after this speed value. As the ambient temperature increased, cell temperatures and module voltage increased, and the maximum temperature difference between cells decreased. It was revealed that the cooling capacity of the system was insufficient for the 7C discharge rate. As the distance between cells increased, cell temperatures decreased, and a more homogeneous temperature distribution occurred. Lower cell temperatures and homogeneous temperature distributions occurred in the front-dual-side and top-dual-side fan positions, where three-dimensional air flow was provided with multiple fan placements. Among all configurations, when T ₘₐₓ and Δ T ₘₐₓ are evaluated together, the best thermal performance was achieved in the top-outlet configuration, with values of 36.75 °C and 6.78 °C, respectively. These findings provide significant contributions to the design optimization of air-cooled lithium-ion battery systems.