A novel ultrasonic transmission coefficient spectrums approach to detecting lithium deposition of lithium-ion batteries

Abstract

According to the movement of lithium-ions between the positive electrode and the negative electrode, the alternate transformation of the state of charge of the lithium-ion battery was realized, which was the charge-discharge cycle. Under the low temperature and high current charging conditions, some lithium ions were deposited on the surface of the anode in the form of lithium metal, resulting in the lithium deposition phenomenon. In this research, an alternate detection method was proposed to probe the lithium deposition based on the ultrasonic transmission characteristics. Firstly, combined with the Biot theory and the transfer matrix method, the theoretical model of ultrasonic reflection/transmission characteristics of multi-layered porous lithium-ion batteries was established. The effect of the state of charge and the lithium deposition layer thickness on the frequency spectrum of the ultrasonic reflection/transmission coefficient was numerically analyzed. Then, the ultrasonic transmission characteristic test system was built, and the relationship between the resonant frequency point and state of charge was investigated experimentally. Finally, the lithium deposition battery was prepared in high-rate and low-temperature conditions. Through the analysis of the experimental measurement results of the shift characteristics of the frequency spectrum of the ultrasonic transmission coefficient, the influence of lithium deposition on the characteristic points of the ultrasonic frequency spectrum was explored. Through Scanning Electron Microscope investigations it can be suspected that the anode sheet showed significant lithium deposition, which was a great extension of the application scope of the non-destructive lithium deposition detection methods.