Experimental Analysis of Thermal Behavior of a Lithium-Ion Battery using Constant Voltage under Different Cooling Conditions

Lithium-Ion Battery (LiB) plays a vital role in the applications from smart phone to Electric Vehicles (EV). In general, LiB is used as the main resource for primary as well as secondary applications because they have advantages such as long cycle life, slow self-discharge, high capacity, and low maintenance. In spite of its advantages, few factors such as protection circuit, efficient thermal management systems, battery material, cost and safety, degrade the performance of the LiB. So, to analyze the thermal behavior of the Lithium-ion battery, it is tested under air, water and oil cooling methods. A LiFeO4 LiB with 3.2 V/ 6Ah capacity is used for the analysis. The nominal voltage and capacity are 24 V and 48mAh respectively. The temperature profile of the battery is tested under different temperature-cooling environments. The experimental results are validated using MATLAB and Minitab software. In MATLAB, the Simulink model is designed to operate a 5HP/240V/1750 RPM DC motor. In this analysis, charging / discharging characteristics, State of Charge (SOC) under different ambient temperatures and motor torque characteristics are obtained. The temperature influences under various cooling methods have to be analyzed using Minitab-2017 software. It is interpreted by Response Surface Methodology (RSM) and contour plot graphical analysis. It gives a very clear picture about the relationship between different factors such as charging / discharging voltage, various temperature points, temperature control with cooling and without cooling. Also, this analysis helps to identify thermal influence on the battery performance where the minimum temperature is very clearly visible. The safe operating temperature can easily be identified for various applications. This analysis aids in the prediction of extreme temperature conditions and provides solutions to protect the system. So, through this analysis, it is possible to identify the optimum operating temperature range of a Lithium-ion battery.