THERMAL MANAGEMENT OF LITHIUM-ION BATTERY PACK USING PCM

Abstract

Environmental issues caused using conventional vehicles are serious concerns nowadays and are dealt with utmost care by the government. Electric Vehicles are one of the most promising solutions in the present era but the fundamental challenge in this shift is the development of proper energy storage that includes a well-designed Lithium-ion battery pack for high-energy applications. The objective of this research is to look for an optimum thermal management technique which limit the maximum temperature within the battery pack. Here we primarily focus on passive cooling technique to control the maximum temperature within the pack. The study illustrates the time-dependent variation of temperature within the module. Initial simulation is carried out at a 3C rate, without the application of PCM, it was observed that the maximum temperature during the charging case reached around 42°C after 1000s which is above the optimal temperature range of 15 to 40 °C for general Lithium-ion cells. Then for the same configuration, simulation is carried out by using Paraffin as Phase Change Material (PCM) within the cells and at the top and bottom where series and parallel connectors are installed. The graph recorded a maximum temperature of 34°C which is approximately equal to the melting temperature of Paraffin. The temperature contours for both cases suggested how PCM is effective in reducing hot-spot regions within the battery pack. The study is further extended to charging rates of 1.5C and 2C. It is observed that with an increase in the C rate the temperature within the pack increases. Without PCM the peak temperature difference between 1.5C and 3C case is 11°C whereas with PCM the difference is reduced to 3.5°C. The study is further extended to find an optimum PCM material for this case. Same study is carried out using Paraffin RT42, Paraffin RT35, Paraffin RT27 and Capric acid. The study shows Paraffin RT27 to be most suitable material for our case as it limit the maximum temperature to 29.5 °C. From mathematical calculations we found that nearly 75% of Paraffin RT27 has changed its state from solid to liquid within time interval of 1000s.