Numerical study on thermal behavior and a liquid cooling strategy for lithium-ion battery

Investigation on the thermal behavior of the lithium-ion battery which includes the temperature response, heat contribution and generation, is of vital importance for their performance and safety. In this study, an electrochemical-thermal cycling model is presented for a 4 Ah 21700 type cylindrical single cell and 3x3 battery pack and the model is validated by experiment on a single cell. Thermal behavior on a single cell is first analyzed, the results show that the heat generated in the charge is smaller than the discharge, and the polarization heat contributes the most to total heat, especially under higher rate. It can also be concluded from the battery pack that the temperature of the cell inside the battery pack is significantly greater than the external battery, while the temperature difference exists the opposite regular due to the worst heat dissipation of the central cell. Finally, after taking the enhanced liquid cooling strategy, the maximum temperature is 320.6 K that is reduced by 9.38%, and the maximum temperature difference is 4.9 K which is reduced by 69.6% at 2C, meeting the requirements of battery thermal management system.