A novel dielectric fluid immersion cooling technology for Li-ion battery thermal management

The objective of this study is to investigate direct cooling performance characteristics of Li-ion battery and battery pack for electric vehicles using dielectric fluid immersion cooling (DFIC) technology. The experimental results showed that Li-ion pouch cell immersed in flowing dielectric fluid assisted with tab cooling showed better cooling performance with 46.8% reduction in the maximum temperature at the positive tab compared to natural convection at 3C discharge rate. The electrochemical-thermal model of Li-ion pouch cell immersed in flowing dielectric fluid assisted with tab cooling was developed using Multi-Scale Multi-Domain (MSMD) approach with Newman, Tiedemann, Gu, and Kim (NTGK) model. A good agreement within +/- 5% was found between the results of numerical study and experimental data. The 50 V battery pack maximum temperature was maintained below 40 degrees C for 5C discharge at the ideal pumping power of 81.7 W. With the application of the proposed DFIC assisted with tab cooling technology, the maximum battery pack temperature was 9.3% lower than the indirect cooling method, confirming the improved cooling performance compared to the conventional cooling method. Under thermal abuse condition with internal short circuit, the peak temperature of 341.7 degrees C was observed for the battery pack and thermal runaway of battery pack was prevented except the affected cell. This study demonstrated the DFIC assisted with tab cooling as a safe and efficient thermal management technology for high-density and high capacity Li-ion battery application in electric vehicles.

Automated summary

This study investigated the direct cooling performance of Li-ion batteries and battery packs for electric vehicles using dielectric fluid immersion cooling technology. Experimental results showed improved cooling performance with a 46.8% reduction in temperature using flowing dielectric fluid assisted with tab cooling. The development of an electrochemical-thermal model and its validation through numerical study and experimental data demonstrated the effectiveness of this cooling technology.