(Invited) Fully-Coupled 3D Electrochemical-Thermal Modeling of Cylindrical Lithium-Ion Batteries

A rigorous three-dimensional electrochemical-thermal model is developed without having to make dimension-reduction approximations to the electrochemical model. The fully-coupled model is developed for the spiral battery in the unwound form taking advantage of the coordinate-transformation technique published in Ref. 1. Key thermal model parameters such as heat capacity, entropy coefficient and hysteresis heating are obtained by direct measurements or by fitting simplified versions of the model to a host of experimental data. The thermodynamics software package – Advanced Electrolyte Model (AEM) – is used to obtain electrolyte transport parameters as functions of concentration and temperature. Exothermic chemical reactions that are triggered under high temperatures are included following Ref. 2-3. The chief safety feature of separator shutdown is modeled and its effects studied under a range of conditions. Model predictions for normal operations as well as under abuse such as internal and external shorts are presented. Comparisons between predictions and data are shown for some external short conditions, demonstrating the accuracy of the model. References M. Gomadam, R.E. White, and J.W. Weidner, J. Electrochem. Soc. , 150 , A1339 (2003). G-H.Kim, A.Pesaran, and R.Spotnitz, Power Sources , 170 , 476 (2007). F.Lopez, J.A.Jeevarajan, and P.P.Mukherjee, J. Electrochem. Soc., 162 , A2163 (2015). Fig. 1. Predicted temperature profile along before separator shutdown during an external short condition. Figure 1