Performance Evaluation of Phase Change Materials for Effective Battery Thermal Management

Lithium-ion batteries (LIBs), over other rechargeable batteries, are being extensively used in Electric Vehicles due to their inherent good and suitable characteristics. However, its performance is sensitive majorly to temperature variations, leading to thermal runaway-related issues. Thermal management is felt essential to protect them from the associated catastrophic issues. Among different thermal management strategies, using phase change materials is energy-effective and works as a passive system. The present work focuses on the use of organic Phase Change Material (PCM) with varying thicknesses (1, 3, 5, 8, and 10mm). The performance of PCMs is studied using Computational Fluid Dynamics (CFD) analysis through ANSYS 2023 R2 platform on two different geometries of LIBs. With the validated model, extensive simulations are performed. Performance is studied regarding peak temperatures at three high discharge rates 5C, 6C and 8C. A comparison is made between two prismatic LIBs. For the shorter duration of working. The temperatures are modestly lower in the case of a larger battery volume than in a smaller one. PCM use helped in achieving uniform temperature across the surface of LIBs; temperatures have drastically decreased with the increase in the thickness of PCM. Different PCM materials, such as RT-40, n-octadecane, capric acid, n-eicosane, lauric acid, and sodium sulphate hexahydrate, are used to observe the efficacy of PCM materials. The thermal conductivity of PCM has played a vital role in achieving safe temperatures. A 52K difference was observed for sodium sulphate hexahydrate compared to the difference without PCM for 6 cells. Simulations were also carried out for 9 cells. The inorganic PCM has shown superior performance, and the battery temperatures are even more sensitive to ambient temperature. It is noted that choosing higher thermal conductivity phase change materials facilitates better thermal management, and also it is suggested that battery operation at lower discharges when ambient temperatures are high.