Coupling Effect of State-of-Health and State-of-Charge on the Mechanical Integrity of Lithium-Ion Batteries

• Published in: Experimental mechanics Vol. 58; no. 4; pp. 633 - 643
• Main Authors: Xu, J., Jia, Y., Liu, B., Zhao, H., Yu, H., Li, J., Yin, S.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-04-2018; Springer Nature B.V
• Subjects: Biomedical Engineering and Bioengineering; Characterization and Evaluation of Materials; Control; Dynamical Systems; Electric vehicles; Engineering; Failure; Integrity; Lasers; Lithium; Lithium-ion batteries; Optical Devices; Optics; Photonics; Rechargeable batteries; Short circuits; Solid Mechanics; State of charge; Stiffness; Strain; Vibration; Lithium-ion batteries; State of charge; State of health; Mechanical integrity; Coupling effect
• ISSN: 0014-4851; 1741-2765
• DOI: 10.1007/s11340-018-0380-9

Two governing factors that influence the electrochemical behaviors of lithium-ion batteries (LIBs), namely, state of charge (SOC) and state of health (SOH), are constantly interchanged, thus hindering the understanding of the mechanical integrity of LIBs. This study investigates the electrochemical failure of LIBs with various SOHs and SOCs subjected to abusive mechanical loading. Comprehensive experiments on LiNi
0.8
CoO
15
Al
0.05
O
2
(NCA) LIB show that SOH reduction leads to structural stiffness and that the change trend varies with SOC value. Low SOH, however, may mitigate this phenomenon. Electrochemical failure strain at short circuit has no relationship with SOC or SOH, whereas failure stress increases with the increase of SOC value. Experiments on three types of batteries, namely, NCA, LiCoO
2
(LCO), and LiFePO
4
(LFP) batteries, indicate that their mechanical behaviors share similar SOH-dependency properties. SOH also significantly influences failure stress, temperature increase, and stiffness, whereas its effect on failure strain is minimal. Results may provide valuable insights for the fundamental understanding of the electrochemically and mechanically coupled integrity of LIBs and establish a solid foundation for LIB crash-safety design in electric vehicles.