2019 - 2021
Dr. Samarjeet Chanda
SERB - Start-Up Research Grant (SRG)
Electric vehicles (EVs) have the potential capability to minimize the severe threats posed by environmental pollution and energy crisis to humankind. Energy storage systems made of lithium-ion batteries are widely used to power these vehicles. Thermal-degradation of batteries caused by temperature change significantly reduces the battery life and imposes a potential safety threat in the form of battery explosion. Increase in cell temperature over and above the threshold leads to thermal runaway which can lead to a terrible catastrophe. Therefore, to ascertain a safe operation environment, rapid dissipation of the heat generated in the battery packs of EVs is required. This necessitates the design and development of effective battery thermal management systems and is the key focus of this research initiative. To this extent, it is proposed to design and develop a composite heat sink comprising of porous metal foam saturated with phase change material for the thermal management of lithium ion battery packs. A numerical thermo-chemical modeling of the battery module at the cell level shall be carried out. Temperature distribution in the battery shall be obtained by solving the energy equation along with the heat generation rate derived from a chemical thermodynamics perspective. The effect of different cooling strategies viz. only air (natural convection), only metal foam/mesh, only PCM and metal foam infiltrated with different percentages of PCM, shall be brought in through the boundary conditions and each cooling strategy shall be critically evaluated. Heat transfer experiments shall be carried out by subjecting the battery module to different charging and discharging cycles, and the cooling strategies as mentioned above shall be evaluated based on its ability to maintain temperature uniformity and prevent thermal runaway. Effect of ambient temperature and relative humidity appropriate to Indian conditions, on the heat removal capacity of the composite heat sink shall be studied. Correlations to predict the geometrical, hydrological parameters and thermal properties of the porous metal foam used in the composite heat sink for maximizing the rate of heat transfer from battery packs shall be developed. Furthermore, a passive auxiliary heat sink based on liquid/two-phase flow in micro/mini channels to extract heat from the molten PCM and solidify it back shall be designed and integrated with the composite heat sink. The effect of thermal contact resistance between the heat sinks and the battery pack on the heat removal effectiveness shall be also studied and suitableengineering materials to minimize the thermal contact resistance shall be proposed. This study, at an application level would lead to the development of an indigenous battery thermal management system capable of operating in Indian conditions and at a fundamental level would improve the understanding of phase change heat transfer in porous media.