EVs (Electric vehicles) have garnered much of attention over the past few decades as a promising solution to greenhouse gases in transportation. In this paper, a feasibility study is performed applying a TE (thermoelectric) device to the energy storage system of an electric vehicle. By applying a TE device to the Li-family battery system, the effectiveness of the TE device for possible cooling or pre-heating of the battery, or to recover the electrical energy from the waste heat are investigated. Based on the simulated flow field and temperature distribution, the effective locations of thermoelectric devices are identified and installed, and their performances in view of heat recovery or pre-heating during winter and cooling performance during summer are evaluated by simulation. In addition, the results are verified through an experimental setup under a controlled environment of air flow and temperature. Based on the simulation and experiment, the overall effectiveness of cooling or heating, and waste heat recovery quantity is evaluated. It is found that, though the cooling or pre-heating energy is small, the functional benefit to the efficiency and charging/discharging performance of battery system can contribute significantly to sound battery operation, hence to the reliability and overall performance of EVs.