A 3D Electrochemical-Thermal Coupled Model for Pouch-Type Lithium-ion Batteries with Counter-Tab Configuration

Abstract

Lithium-ion batteries (LIBs) are the dominant energy source for electric vehicles (EVs) and battery energy storage systems (BESS) owing to their superior performance compared to other storage technologies. However, thermal management remains a critical challenge, as LIBs must operate within a tight temperature range (typically 25-40ºC) and maintain spatial temperature uniformity (ideally <5ºC). Emerging large-format (>50 Ah) LIB pouch cells are particularly susceptible to spatially non-uniform heat generation driven by higher current densities near their tabs, resulting in significant temperature gradients that compromise both performance and lifetime. This work presents a three-dimensional electrochemical-thermal (ECT) coupled model that addresses the limitations of existing ECT models in accurately predicting spatial temperature gradients across different C-rates, particularly in large-format pouch cells with counter-tab configurations that exhibit two hot spots near the cell’s opposite tabs. By incorporating a heat-generation distribution factor, this work’s ECT model captures non-uniform Joule heating arising from distributed current density in the cell’s metal current collectors, in turn enabling accurate predictions of spatio-temporal temperatures in these large-format pouch cells. Experimental validation through voltage and temperature measurements confirms the accuracy and robustness of the proposed model, demonstrating its ability to predict the thermal characteristics of large-format pouch cells, which are increasingly adopted in EVs and BESS. The validated model is employed to conduct a comprehensive sensitivity analysis to examine how variations in electrode layer properties influence the magnitude of volumetric heat generation rate, and the role of tab geometry in controlling its spatial distribution.