Analysis of BTMS for Thermal Performance with Varying Casing Thickness

Over the last few decades, renewable energy technologies have picked up pace with fears of exhausting non-renewable resources and environmental degradation. Batteries made with lithium-ion (Li-ion) are the foundation of electric vehicles (EVs) and are essential for high density energy storage. Lithium-ion (Li-ion) batteries are a key to energy storage with high energy density and are now the backbone of electric vehicles (EVs). Safe and efficient thermal regulation of lithium-ion battery assemblies is absolutely essential. Liquid cooling has been one of the promising Battery Thermal Management System (BTMS) solutions among many others. This work explores the thermal efficiency of lithium-ion battery arrays with various cylindrical casing thicknesses between 20 mm and 28 mm. A two-dimensional numerical model is established for 20 Li-ion 18650 cylindrical cells in staggered and in-line configurations. Simulations are conducted for 1C to 5C discharge rates under a constant coolant flow rate. Results are compared with a constant thickness case and exhibit good agreement within +7% error. Results show improvement in temperature uniformity towards the cooling fluid flow route with varying casing thickness. The maximum temperature gradient between the first and last cell is decreased to 0.1 K at 1C and 1.8 K at 5C. In contrast, the new design increases the heat transfer by 10-15% compared to constant thickness casings.