A novel spray-based immersion cooling for Li-ion batteries: An experimental comparison with flow immersion

• Experimental comparison of spray- and flow-based immersion cooling is presented. • Effect of immersion depth on thermal performance and uniformity is analyzed. • Reduced-fluid spray cooling is proposed for lightweight battery management Lithium-ion batteries have become the backbone of electrical vehicles, and managing their thermal behavior under high charge–discharge rates is increasingly important. This study introduces a novel spray-based immersion cooling method and experimentally compares its three partial submersion configurations against a conventional fully submerged flow-based immersion cooling system, using a 9S7P battery pack. The battery is operated under demanding charge and discharge rates ranging from 1C to 4C, while coolant flow rates are varied between 2 and 4 L/min. The results indicate that spray-based immersion cooling with minimal submersion achieves the lowest maximum cell temperatures and smallest temperature difference across the pack. This configuration reduces the dielectric liquid usage by up to 85 % compared to the flow-based approach. When subjected to high flow rates, this configuration delivers up to 19 % reduction in peak temperature, limiting it around 34 °C at 4C discharge rate. These results show that spray-based immersion cooling with low liquid volume and precise nozzle placement offers a highly promising direction for efficient, lightweight, and scalable battery thermal management system.