Finite Element Thermal Model and Simulation for a Cylindrical Li-Ion Battery

Due to the advantages of high energy density, no memory effect, and long cycle life, Li-ion batteries are being widely studied and proverbially used as power sources for electric vehicles. The performance of Li-ion battery systems is largely dependent on the thermal conditions and the temperature gradient uniformity inside. In order to tackle with the inconsistency problems of temperature distribution among battery cells in a battery pack, a thermal model for a cylindrical battery based on the finite-element method was developed. Physical structure and electrochemical reactions were both considered, and the initial conditions, boundary conditions, and thermal characteristic parameters of the battery components were determined through theoretical calculation and experiments. The discharge thermal characteristics were further investigated. In addition, the experiments were conducted to verify the accuracy of the presented model. Comparing the theoretical analysis with experimental results, it shows that the relative errors between the simulation and the tests are small at varied ambient temperatures and discharge rates. Therefore, the model can be efficiently applied to predicting the thermal behaviors of Li-ion batteries in practical applications.