Active temperature control of Li-ion batteries in electric vehicles

Due to the high reliability and cost-effectiveness, Lithium-ion (Li-ion) batteries find their wide-spread use in electric vehicle applications. However, EV batteries operate in harsh environments and the body temperature of each cell in a battery pack tends to be largely different, significantly reducing life expectancy of the batteries. The final aim of this work is to propose an active temperature control method to equalize the temperature distribution of the batteries. However, the first step at the present stage attempts to improve the unbalanced thermal problem existing in current battery packs by optimally arranging battery cells and controlling the coolant flow rate. The results show that all cells within the battery pack can be maintained within a few °C of each other during operation. Therefore, unbalanced electrical properties can be significantly alleviated between different cells so that the overall performance and maintenance of the battery pack is improved.