How a Li-Ion Battery Talks: Electrochemical and Mechanical Behaviors of the Battery Using in-Operando Acoustic Emission

Abstract

Degradation of a Li-ion battery involves multiple mechanisms that are strongly coupled with each other. Th highly coupled nature of degradation mechanisms makes it complex to understand dynamic electrochemical and mechanical behaviors of the battery. In-operando acoustic emission (AE) technique can provide fundamental insights into the dynamic behaviors of the battery during operation. However, it remains unclear how different types of AE signals are linked to electrochemical and mechanical events occurring inside the battery. Here, we show our efforts to develop an in-depth acoustic analysis to correlate different types of AE waveforms with electrochemical and mechanical phenomena of the battery using a commercial, used battery pouch cell. The hits from the AE phenomena were analyzed using the waveforms and their Fast Fourier Transform (FFT) to get the frequency spectra of the AE sources. Our results show how particle- and electrolyte-level fracture, gas generation, intercalation-induced stress processes are linked to different types of AE hits.