Thermal Simulation of Power Lithium-ion Battery Under Low Temperature and Preheating Condition

Low temperature preheating technology is very important for improving battery performance and preventing battery accidents. In this paper, external preheating method by using of electrothermal plate at the bottom of the battery is adopted to study the temperature field distribution of it. Firstly, the transient heating model of prismatic power lithium ion battery is established, and the segmented thermal resistance model of its jelly roll(JR) is proposed firstly, furthermore, The thermal conductivity of each part of JR is calculated based on the series and parallel thermal resistance formula, respectively. Finally, based on the finite element model, the temperature distribution during battery heating is simulated by using the software Fluent Ansys. The simulation results show that when the battery JR temperature increases from -30 degrees C to the maximum temperature of 60 degrees C, the heating time is 1035s, at this time, the temperature at the its geometric center is only 2.5 degrees C, so the temperature inside and outside the battery is not uniform and an local temperature is high.