Measurements and Modeling of the Temperature of a Li-polymer Battery Provided with Different Coatings for Heat Dissipation

The battery efficiency is strongly affected by the operating temperature, granting the best performance in a limited range. Great attention is given to the design and the testing of materials for the battery heat dissipation. In the present study, the thermal behavior of a Li-polymer cell, which is part of a battery pack for electric vehicles, is investigated. The cell is provided with different coatings of carbon, graphene, and silicone, used in turn, to dissipate the heat generated during the operation in natural convection. The coating is placed only on one side of the battery while the other one is inspected via thermal imaging. Optical diagnostics in the infrared band are used to evaluate the bi-dimensional distribution of the battery surface temperature and the effect of the coatings. Different operating conditions are tested by varying the current demand. Part of the experimental results is used to set up and tune a thermal model of the battery, also estimating the thermal parameters as convective heat transfer coefficient and specific heat capacity. Then, the remaining data are used to validate the model predictions. The results of this work present the potential benefits and drawbacks of different coatings for battery cooling and provide a simple theoretical model for the support in the design.