Investigation of the immersion cooling system for 280Ah LiFePO4 batteries: Effects of flow layouts and fluid types

Abstract

The widespread use of high-capacity LiFePO4 batteries (LFPB) is crucial for meeting the growing demand for energy storage systems (ESSs). This requires effective thermal management systems, and single-phase immersion cooling (SPIC) is emerging as a promising option due to its superior cooling capability. This paper investigates the effects of flow layout and fluid type on 280 Ah LFPB under SPIC through experimental and numerical analyses. Three flow layouts (opposite sides, same side, and jet impingement) are proposed, and six fluids are used for simulations. Results show that the jet impingement achieves the lowest temperature and pressure drop. During 1P discharge with DF1 flowing at 0.006 m/s, the maximum temperature, temperature difference, and pressure drop are 317.67 °C, 4.71 °C, and 0.09 Pa, respectively. Varying flow velocities within 0.006–0.053 m/s significantly impact battery temperature in the same-side layout. The volatility due to different fluid types, including CV,ΔP (pressure drop), CV,Tmax (maximum temperature) and CV,ΔT (temperature difference) are presented. As the flow velocity increases, CV,ΔP decrease by 35.9 %, 39.4 %, and 36.2 % for opposite sides, jet impingement, and same side, respectively. CV,Tmax increases with the P-rate, and the same-side layout has the lowest CV,Tmax, below 0.9 % at 0.5P and 0.6 % at 1P. This study emphasizes that the effect of fluid type should be considered in the design of flow layouts, especially at low flow rates. Experimental observation indicates that no ignition or explosion occurred during battery thermal runaway under SPIC. The maximum battery temperature during thermal runaway is 241.9 °C. This research provides valuable insights into SPIC application and fluid selection for ESS.