Lithium-ion batteries (LIB) are widely being used in the field of electric vehicles, their high-power density, low resistance, compactness and low self-discharge rate. These make LIBs an ideal choice for use in electric vehicles (EV). To increase the reliability of LIBs, a proper battery thermal management system is required. This thesis presents a finite volume based Computational Fluid Dynamics (CFD) aero-thermal analysis for a pack of high energy density cylindrical lithium-ion batteries. This study presents first the development of a CFD framework required for a comprehensive aero-thermal investigation. This includes investigations on the effectiveness of turbulence modeling approaches in capturing local hot-spots developed for a range of inlet velocities and configurations of the lithium-ion battery pack. Turbulence models investigated include Mentors SST k-ω, Launder and Spalding standard k-ε, realizable k-ε and elliptic blending k-ε. The results from these simulations are compared against published experimental wind-tunnel data. Simcenter Battery Design Studio (BDS) is used to generate a detailed and in-dept model of the LG INR 18650 MJ1 (LiNiCoMnO2) cell. The cell from BDS is imported in Simcenter Starccm+ 2020.2 where the simulation is set-up to monitor voltage variation, discharge rate current, temperature distribution within the pack, maximum temperature of aligned, staggered, and cross configuration for various inlet velocities. The results of these simulations are compared, and it is found that, in spite of all its short comings, the standard k-ε model is the most accurate model for such analysis. It is also observed that the dependency of heat generation on discharge current is significant, the battery performance is affected by the ambient temperature, and the aligned arrangement has the best temperature uniformity and cooling effectiveness. Lastly, there is significant effect on the stability of the simulation depending on the way the boundary condition is modeled is projected.