Thermal management of high-energy lithium titanate oxide batteries using an effective channeled dielectric fluid immersion cooling system.

• Lithium titanate oxide batteries are analyzed using the equivalent circuit model. • An effective channeled dielectric fluid immersion cooling system is introduced. • Performance is evaluated considering battery aging and dynamic loading. • The cooling system performs well even at high road gradeability conditions. Lithium titanate oxide is becoming a prominent alternative to graphite as an anode in lithium-ion batteries due to its long cycle life, fast charging/discharging, and ability to function at low ambient temperatures. However, lithium-ion batteries are susceptible to catastrophic thermal runaway under extreme and abusive conditions. The present study proposes a novel channeled dielectric fluid immersion cooling system for the 23Ah lithium titanate oxide batteries modeled using an equivalent circuit model within a multi-scale, multi-domain framework using the commercial solver ANSYS. The novel cooling system reduced maximum temperature and improved temperature uniformity with less immersion fluid requirement than the generic designs. Hydrofluoroether HFE-6120 turned out to be the most effective coolant, and 0.5LPM is the optimum flow rate. When subjected to dynamic loading, the proposed cooling system restricted the maximum temperature to 299.2 K in the aged battery pack with 3972 cycles. Further, the reduced order model is utilized in lieu of the equivalent circuit model to reduce computational time for analyzing the battery pack. Compared to the full-order equivalent circuit model, the reduced order model efficiently captures the battery dynamics with minimal deviations of 1 % and 1.5 % in voltage and temperature, respectively. The computational time is reduced by 26 % with the reduced order model. The proposed cooling system limits the maximum temperature and non-uniformity in the battery pack to 302 K and 1 K under aggressive scaled-down US06 loading conditions with continuous 9° gradeability. This research will be helpful for the future development and understanding of immersion cooling systems for high-energy LTO-based batteries under the impact of aging and gradeability. [ABSTRACT FROM AUTHOR]