A 3D distributed circuit-electrochemical model for the inner inhomogeneity of lithium-ion battery

Performance degradation and operational safety are vital issues for lithium-ion batteries. After summarizing each battery failure accident, it is found that local defects caused by the inconsistency within the battery are one of the critical reasons for battery failure. To study the influence of the internal inconsistency of the battery on its safety performance, a 3D distributed circuit and electrochemical coupling model that can reflect the internal structure of the battery are established. Moreover, the model's solid-phase potential and liquid -phase lithium ion concentration are corrected to improve the simulation accuracy. The RMSE of the model is less than 10 mV under 1.0 C constant current charging condition and dynamic discharge condition. Based on the proposed distributed model, this paper investigates the influence of the cell size, tab position, and other structural parameters on the internal inconsistency of the cell. And the phenomenon of current reversaland the possible local lithium deposition away from the tab position is discovered. The model's correctness and efficacy in simulating internal inconsistencies are further illustrated by reproducing the local lithium deposition of a homemade LFP cell and a commercial NCM cell by controlling the charging current.

Automated summary

This paper investigates the impact of internal inconsistency of lithium-ion batteries on their safety performance, using a 3D distributed circuit and electrochemical coupling model that reflects the internal structure. The model is corrected to improve simulation accuracy, and it is found that cell size, tab position, and other structural parameters affect the internal inconsistency. Phenomena like current reversal and local lithium deposition away from the tab position are discovered. The model's correctness and efficacy are further illustrated by reproducing local lithium deposition using controlled charging current.