Electrode structural evolution-based assessment of Li-ion battery safety and lifespan characteristics

Lithium-ion batteries simultaneously face capacity degradation and the accumulation of safety risks during cycling. Current research on State of Health (SOH) primarily focuses on evaluating capacity and internal resistance parameters during battery ageing. However, existing evaluation methods cannot distinguish the independent evolution patterns of these two phenomena, leading to mutual interference between safety monitoring and lifetime prediction. This study, by establishing an electrochemical mechanism model and integrating Incremental Capacity Curve (ICV) analysis, systematically elucidated the evolution characteristics of five degradation modes. Key findings indicate that thermal runaway risk and capacity aging follow distinct structural degradation pathways. Specifically, an increase in q Li reflects safety deterioration caused by cathode structural instability (indicating thermal runaway propensity), while the accumulation of q p signifies capacity degradation resulting from anode active material loss (accelerated aging). Based on this mechanistic distinction, the study achieved a decoupled quantitative assessment of safety status and aging status, thereby providing a technical solution and theoretical basis for power battery management systems to synchronously monitor these dual health indicators.