Analysis of the Thermal Behavior of Li-Ion Pouch Battery Cell - Part I: Finite Element Simulations Including the Entropic Coefficient

Nowadays, accurately predicting the operating temperature field in Li-Ion batteries is fundamental to properly design thermal management solutions to avoid phenomena like aging or thermal runaway. Specific approaches to describe the thermal behavior of Li-ion pouch battery cells have been investigated and the findings have been organized as a two-part manuscript. In particular, in this paper, corresponding to the Part I of the study, finite element simulations will be performed, based on the solution of 2D Laplace equation for potential field, and on 3D transient heat conduction equation to predict the temperature accounting for heat source term for the multiphysics coupling. In order to perform an exhaustive parametric analysis, correlations between some parameters like resistances or entropy coefficients, are mandatory. In this contribution, heat transfer predictions on a Li-Ion pouch cell are presented. Various regressions have been performed to obtain electric resistance evolution with SOC, while for the entropy coefficient different regressions have been compared too. Results are shown to be in excellent agreement with available literature data, highlighting that temperatures are generally much higher close to the tabs mainly due to the local increase in the current density. Finally, a parametric analysis for the exterior heat transfer coefficient has been carried out to underline the importance of an appropriate thermal management in such applications. The presented approach will be used to validate the SPICE-compatible battery model described in Part II.