Does the electrolyte flow in a lithium-ion battery? A perspective from the electrochemical–thermal–hydraulic–mechanical coupling in porous media

Abstract

This paper presents an electrochemical–thermal–hydraulic–mechanical (ETHM) coupling model by introducing the electrolyte flow field into the model of lithium-ion batteries (LIBs). First, the ETHM coupling model is established on the basis of the electrochemical–thermal–mechanical (ETM) coupling model and poroelasticity model. Then, the ETHM coupling model for the discharge of LIBs is numerically resolved and verified against the ETM coupling model using the commercial 11.5 Ah LiMn2O4 battery as an example. Subsequently, the flow and deformation characteristics (such as the Darcy's velocity, the pore pressure, the Péclet number, and the volumetric strain) are analyzed. The results suggest that the electrolyte does flow during the operation of LIBs. Furthermore, the electrolyte flow is governed by the internal pore pressure gradient induced by the poroelastic effect. The electrolyte flow behavior is also influenced by the boundary conditions. The findings in this study are of benefit to obtain in-depth understanding of the coupling mechanisms among the electrolyte flow field and the stress (strain) field, the temperature field, and the electrochemical field.