Visualization Analysis and Impedance Analysis for the Aging Behavior Assessment of 18650 Cells

This work presents a comprehensive study on the aging behavior of 18650‐type lithium‐ion batteries, focusing on the uneven intercalation of lithium ions during fast charging processes. It introduces a novel approach using color visual recognition technology to analyze color changes in the graphite anode, indicative of lithiation levels. The study employs X‐ray diffraction (XRD) and distribution of relaxation time (DRT) techniques to validate and analyze the observations. The study emphasizes the significance of electrode impedance, the positioning of battery tabs, and electrolyte distribution in influencing the aging dynamics of lithium‐ion batteries. Furthermore, the paper presents an innovative impedance Transport‐Line Model, specifically developed to capture the evolution of polarization impedance over time. This model offers a deeper understanding of the internal mechanisms driving battery aging, providing valuable insights for the design and optimization of lithium‐ion batteries. The research represents a significant contribution to the field, shedding light on the complex aging processes in lithium‐ion batteries, particularly under the conditions of fast charging. This could lead to improved battery performance, longevity, and safety, which are critical for the wide range of applications that depend on these energy storage systems.