Immersion cooling innovations and critical hurdles in Li-ion battery cooling for future electric vehicles

Battery electric vehicles are pivotal in advancing the circular economy by reducing carbon footprints through their sustainable design and low-emission operations. The growing demand for electric vehicles with fastcharging capabilities and high-energy-density Li-Ion batteries has significantly intensified the importance of effective battery thermal management systems, as elevated temperatures can lead to rapid battery degradation and thermal runaway. The study of typical battery cooling techniques seems insufficient to attain temperature homogeneity in the battery pack during fast-charging applications. Therefore, to address this significant challenge, a holistic analysis of immersion cooling technology for battery thermal management is provided, which has the heat transfer rate in the order of magnitudes compared to a typical battery cooling mechanism. In immersion cooling, the battery is submerged in a dielectric coolant, establishing direct contact between the coolant and the heat source. The current state-of-the-art immersion-cooled battery thermal management systems with single-phase and two-phase techniques are comprehensively reviewed. The performance of available immersion coolants is analyzed, and a suitable coolant selection strategy is formulated for battery immersion cooling applications. Besides, critical issues like suppression of thermal runaway, nucleate boiling, immersion coolant effects on battery, and fluid flow optimization with future directions have been discussed comprehensively. A detailed discussion on the economics of battery immersion cooling as a cost-effective solution is included. This study offers an up-to-date review of battery immersion cooling, fostering an improved understanding of advancement in thermal management systems in the context of promoting a circular economy and zero emissions.