Thermal Management of Li-ion Batteries by using Active and Passive Cooling Techniques /

Abstract

To enhance the safety of Li-ion batteries, it is crucial to understand their behavior when exposed to high temperature. The structural arrangement and identical cell spacing with use of proper thermal management system are key aspects related to safety of Li-ion batteries. In this study a battery pack was constructed by using nine 26650 Li-ion cells, which are discharged on 1C rated and series of experiments conducted on different battery pack thermal management systems including air cooling and PCM based thermal management of battery pack to evaluate the effects of thermal management on the performance of the battery pack. Inorganic phase change material sodium sulphate decahydrate was used to evaluate the thermal management of battery pack. The results show the hike in temperature of battery pack of about 10 ℃ in normal air-cooling operation of battery when discharged at 1C rate, as in comparison with forced air cooling the maximum temperature hike was about 7 ℃ and in PCM based thermal management system was the temperature hike was up to 4.4 ℃. each monitored cell temperature was also analyzed for each thermal management system. With the help of simple modeling, it shows the maximum temperature hike on normal operation for the battery can be reduced up to about 4.2 ℃ and by 6.4 ℃ by using forced air cooling and PCM based thermal management system respectively. It was also analyzed that PCM based thermal management systems does not show any sharp hike in temperature of battery pack cell, which indicated that PCM used properly thermally managing the battery heat. On comparison between these three systems, it clearly shows that PCM based thermal management system having sodium sulphate decahydrate as PCM shows the best result in thermal management of battery pack which can be the potential candidate for future electric vehicles battery pack.