Thermal optimization of an air-cooling system of 2 kAh battery module for energy storage systems

Abstract

Effective thermal management is crucial for ensuring the safety and longevity of lithium-ion battery energy storage systems (ESSs) by preventing localized heat accumulation and thermal runaway. In this study, an optimized air-cooling strategy was investigated for a 2 kAh commercial ESS tray comprising twenty 100-Ah prismatic LiFePO 4 (LFP) cells. Cell-level heat generation during 1C charge–discharge cycles was experimentally quantified (5,000–7,500 W/m 3 , cycle-averaged) and utilized as the thermal boundary condition for a three-dimensional computational fluid dynamics (CFD) model, which was validated against experimental tray temperature measurements (standard deviation of 1.3°C between simulation and measurement). Eight design variants, incorporating aligned/staggered heatsinks with four flow-guide configurations, were compared. The best-performing configuration reduced the average cell temperature by 3.9°C (from 43.4°C to 39.5°C) and the cell-to-cell temperature standard deviation by 0.6°C decrease relative to the validated baseline, corresponding to an approximately ≈30% improvement in temperature uniformity. These performance figures show the simulation results obtained using the model validated against tray-level measurements. Parametric studies across thermal loads of 100–150% and airflow rates of 50–125% confirmed the robustness of the proposed design. Even under a 150% thermal load, the average cell temperature was maintained below 46°C, well within the safe operating window of LFP cells. These quantitative results provide practical design guidelines for the air-cooled thermal management of large-scale, high-capacity ESS trays.