A Temperature and Current Rate Adaptive Model for High-Power Lithium-Titanate Batteries Used in Electric Vehicles

Lithium-titanate batteries with Li4Ti5O12 anodes, which show excellent power characteristics and cycle life, are promising candidates for electric vehicle applications. However, the conventional equivalent circuit model (ECM) becomes insufficient when the temperature and current rate range widely. In this article, a novel battery model is established by rederiving and simplifying the Butler-Volmer equation carefully, and then, embedding it in the ECM along with the Nernst equation to adapt the model to the variation of the temperature and current rate. Furthermore, the non-Arrhenius behavior of the ohmic resistance is considered in this article and corrected by a quadratic polynomial method. The proposed model is thoroughly validated at different temperatures with both constant current tests and dynamic current tests, and the verification results show satisfying accuracy. Through the comparison with the conventional ECM, significant improvement on model performance is exhibited.