Lithium-ion batteries, which are common nowadays in laptops, cell phones, toys, and other portable electronic devices, are also viewed as a most promising advanced technology for electric and hybrid electric vehicles (EVs and HEVs), but the battery manufacturers and automakers must understand the performance of these batteries when they are scaled up to the large sizes needed for the propulsion of the vehicle. The performance, life cycle cost, and safety of EVs and HEVs strongly depend on their energy storage system and a major challenge in the development of next generation EV and HEV technology is the management and control of operating temperatures and heat generation. In addition, accurate thermo-physical property input is crucial to thermal modeling. Therefore, a designer must study the thermal characteristics of batteries for the improvement in the design of a thermal management system and also for thermal modeling. This work presents a purely experimental thermal characterization in terms of the measurement of temperature gradient and temperature response of a lithium-ion battery utilizing a promising electrode material, LiFePO4, in a prismatic pouch configuration. The experiment was designed to obtain the thermal images of LiFePO4 cell to qualitatively evaluate the thermal behaviour and temperature distribution with IR (Infrared Radiation) imaging technique at different discharge rates of 1C, 2C, 3C, and 4C. A “FLIR System” Therma CAM model S60 IR camera is used in this work to obtain thermal images. The measurements of temperature rate of change (dT/dt) and temperature gradient (dT/dy) were performed along lines traced (one near the anode, second near the cathode, and third at the center of the cell along the height of the cell) across the battery surface. The results were compared in magnitude to literature values and provided confirmation that the non-uniform heat generation leads to non-uniform temperature distribution.