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

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Lithium (Li) plating is a critical safety issue in lithium-ion batteries (LIBs).
• Understanding the correlation between Li plating and thermal safety is crucial for battery management.
• Existing methods often focus on Li plating occurrence rather than its degree.

Purpose of the Study:

• To develop a quantitative method for assessing the degree of Li plating (D_Li) in LIBs.
• To establish a link between D_Li and the thermal safety characteristics of LIBs.
• To create a framework for Li-plating risk assessment and thermal safety grading.

Main Methods:

• Construction of low N/P LIBs to induce controllable Li plating.
• Thermal response tests and post-mortem characterizations to analyze Li plating and interfacial degradation.
• Development of a non-destructive diagnostic model based on pressure signal evolution.
• Accelerating Rate Calorimetry (ARC) to evaluate thermal safety characteristics.

Main Results:

• A quantitative descriptor (D_Li) for Li plating degree was established.
• Increasing D_Li correlates with increased Li plating, side-reaction products, and interfacial degradation.
• A non-destructive model accurately predicts D_Li based on pressure signals.
• ARC results show a monotonic decrease in self-heating temperature with increasing D_Li.
• Identified D_Li thresholds (20% and 30%) for thermal safety grading.

Conclusions:

• The study successfully quantifies Li plating degree and its impact on LIB thermal safety.
• A novel framework for D_Li diagnosis and safety grading was developed and validated.
• The proposed approach advances LIB safety assessment from identification to quantitative risk evaluation.