Lithium‐Ion Battery Safety Evaluation by Quantifying Lithium Plating Degree Based on Pressure Signals

ABSTRACT Lithium (Li) plating poses a major challenge to the thermal safety of lithium‐ion batteries (LIBs). In this work, low N/P LIBs are constructed to induce controllable Li‐plating, and thermal response tests are performed to correlate Li‐plating degree with thermal safety characteristics. A quantitative descriptor of Li‐plating degree ( D Li ) is established, and post‐mortem characterizations show that increasing D Li is accompanied by the accumulation of Li‐plating and side‐reaction products, along with aggravated interfacial degradation. Based on the evolution of pressure signals during calibration, a non‐destructive diagnostic model for D Li is further developed. Accelerating rate calorimeter (ARC) results show that the first detectable self‐heating temperature of low N/P cells decreases monotonically with increasing D Li , indicating a progressively reduced thermal safety margin. Accordingly, D Li thresholds of 20% and 30% are identified, and a thermal safety grading and battery management framework is established. Cross‐scale validation in commercial 12 Ah cells shows that the predicted D Li values and safety grades agree well with the observed thermal runaway behaviors. Overall, this work advances Li‐plating assessment from occurrence identification to the quantitative diagnosis of Li‐plating degree and the corresponding thermal safety grading. The proposed framework provides a basis for Li‐plating risk assessment and safety evaluation of LIBs.