The Indian market for battery-powered electric vehicles (xEV) is growing exponentially in the coming years, fueled by tumbling lithium-ion battery prices and favorable government policies. Lithium-ion battery is leading in clean mobility ecosystem for electric vehicles. LiBs efficient and safe performance for tropical climatic conditions is one of the primary requirements for xEV to succeed in India.
The performance of LiBs, however, is impacted due to ambient temperature as well as the heat generated within cell due to the load cycle electrochemical reaction. The acceptable operating temperature region for LiBs normally is between 20 °C to 45 °C and anything outside of this region will lead to degradation of performance and irreversible damages. Therefore, understanding the thermal behavior is very crucial for an efficient battery thermal management.
In this study the authors have focused on battery module thermal management by incorporating the thermal interface material (TIM) considering the target application of 2W & 3W EVs. A 3X3 battery module of 3s3p configuration were made with 21700 cylindrical form factor cells. The role of thermally conductive & electrically insulating silicone encapsulant for the thermal benefit and better thermal management was studied whose conductivity ranges from 0.48 W/mK to 2.7 W/mK. The experiments were carried out in two ambient temperature i.e. 25 °C & 45 °C. The discharging of the module was carried out at 1C. To analyze the thermal profile of the cells in the module, temperature measurements were acquired at eight locations with thermistors. It was observed that there is significant drop of Maximum temperature (Tmax) of greater than 10°C with TIM and the temperature uniformity (ΔT) is observed to be within 3 °C along with TIM. All the experiment was first carried out through virtual simulation. Equivalent circuit model of the cell was modelled from HPPC test and electro thermal virtual simulation of the experiments were carried out at cell and module level. Good correlation is observed and used for optimization of the BTMS design. Based on the output, authors conclude that the silicone-based TIM have greater role to play for the efficient battery thermal management in the battery pack.