Detection of the knee point in lithium- ion battery degradation using a state- of- charge- dependent parameter

• 成果类型: Article
• 署名作者: Kim, Hyunjae; Kim, Inwoo; Kim, Minsoo; An, Seongha; Ahn, Hyo Chul; Park, Dongmin; Lee, Jun Hee; Kang, Chun Yong; Choi, Jang Wook
• 署名单位: Seoul National University (SNU); Seoul National University (SNU); Seoul National University (SNU); Hyundai Motors
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-10343
• DOI: 10.1073/pnas.2424838122
• 发表日期: 2025-06-10
• 关键词: lifetime prediction; modes; cells; capacity

摘要

The rapidly expanding lithium- ion battery (LIB) market has heightened the demand for efficient diagnostics for in- use cells and the reliable grading of used cells. Various purpose- built analysis tools and statistical algorithms have been developed, but often rely on redundant instrumentation and computationally intensive procedures. Here, we propose using the variance of the capacity difference between 0.2C and 1C, Var(Delta Q0.2C- 1C(V)), based on the strong correlation between the interfacial state of the anode and mode of capacity degradation, as a measure of the health state of individual cells. A single- point off- board measurement of Var(Delta Q0.2C- 1C(V)) indicates whether a particular cell is experiencing self- limiting or accelerating degradation and is thus near a knee point in its cycle life. This assessment additionally provides a quantitative criterion for differentiating used cells for reuse or recycling. Our findings suggest that utilizing state- of- charge- dependent key electrochemical properties enables the cell health to be accurately monitored, thereby promoting sustainability in the expanding battery market.