Enhanced immersion cooling using laser-induced graphene for Li-ion battery thermal management

Abstract

Efforts to mitigate environmental pollution from the use of petroleum-based energy sources have promoted research on rechargeable secondary batteries for applications such as electric vehicles and energy storage systems. In this context, Li-ion batteries have attracted significant interest. Notably, the thermal management of such batteries is crucial for achieving a stable output and long lifespan and reducing the risk of thermal runaway. Despite extensive exploration of various cooling schemes, thermal management techniques for Li-ion batteries continue to face challenges due to the high thermal resistance resulting from low thermal conductivity of thermal interfacial materials and inadequate convective heat transfer. Therefore, this study is aimed at using laser-induced graphene (LIG) to enhance the heat transfer characteristics and battery thermal management. LIG is applied through direct laser irradiation on the polyimide substrate of a LiFePO4 battery. Thermal tests conducted under a discharge rate of 5C demonstrate that immersion cooling using HFE-7000 on the LIG surface substantially reduces the temperature increase by up to 84.3% compared with conventional air cooling. In addition, immersion cooling with LIG surfaces results in outstanding cooling performance through nucleate boiling, attaining a maximum temperature of 37.5 °C, which is lower than that (43.5 °C) on a pristine polyimide surface. Overall, this research provides valuable insights into the thermal management of high-performance batteries operating under extreme conditions, such as high-speed charging, high-power discharging, and high-temperature conditions, with significant implications for future applications.