Probing layer interface behavior in Lithium-ion batteries via concurrent ultrasonic and modal measurements

Lithium-ion batteries are pivotal in various technological applications, from powering electric vehicles to supporting renewable energy storage systems. Understanding and monitoring the intricate chemo-mechanics within lithium-ion cells is imperative for ensuring their reliability and performance over time. Previous research has shown that both ultrasonic and vibrational measurements provide a measure of a cell’s state of charge (SOC) and state of health (SOH) and provide indications of existing or previous thermal or electrical abuse. Recent work suggests that ultrasonic and modal analysis may provide complementary insights into the evolution of layer interfaces during early-life aging due to charge-discharge cycling J. Acoust. Soc. Am., 154, A284 (2023). This work presents the results of concurrent ultrasonic and modal measurements over multiple charge-discharge cycles. Namely, we monitor concurrent changes in the ultrasonic time-of-flight and signal amplitude and the resonance frequency of a clamped-clamped 10 Ah Nickel–Manganese–Cobalt pouch cell as a function of electrical cycling. The evolution of these metrics paired with analytical and numerical models of the cell will be used to understand changes in the material properties at layer interfaces and potential structural alterations within the battery which may be important indicators of SOC and early-life aging mechanisms.