Abstract:

IIn recent years, accidents caused by thermal runaway of lithium-ion batteries have occurred frequently. Timely warning and effective intervention before thermal runaway are of great significance for ensuring personnel safety and reducing property losses. As a non-destructive and rapid characterization method, electrochemical impedance spectroscopy technology has received widespread attention in the field of lithium-ion battery thermal runaway warning. Firstly, the measurement principle and equivalent circuit model of electrochemical impedance spectroscopy were introduced, and the principle and characteristics of using electrochemical impedance spectroscopy for monitoring and early warning of thermal runaway in lithium-ion batteries were analyzed; Secondly, the current application of electrochemical impedance spectroscopy in early warning of thermal runaway in lithium-ion batteries was summarized, including direct methods and indirect methods such as internal temperature monitoring, internal short circuit monitoring, and lithium deposition detection, as well as thermal runaway warning methods combined with temperature sensors, gas sensors, and other methods. The practical application effects of various methods were discussed from the aspects of parameter selection, characteristic frequency determination, and warning index establishment, and the advantages and disadvantages of each method were summarized; Finally, the future development direction and trend of electrochemical impedance spectroscopy technology for early warning of thermal runaway in lithium-ion batteries were discussed, providing reference for establishing accurate and universal warning methods and improving the safety of lithium-ion batteries.

Key words: lithium-ion battery, thermal runaway, electrochemical impedance spectroscopy, early warning methods