Ultrasonic testing leverages high-frequency sound waves, well beyond the range of human hearing. When deployed for monitoring lithium-ion batteries, these ultrasonic waves engage with the battery's internal structures. The reflections of these waves, specifically the time-of-flight (TOF) and amplitude of the first echo peak (PA), carry invaluable data about the battery's health.
Lithium-ion batteries (LIBs) have become an integral part of EVs and energy storage applications. Ensuring their safety and longevity through effective health monitoring is of paramount importance. Traditional assessment methods often lack the ability to provide real-time state-of-health (SOH) insights. Addressing this challenge, Wu Y et. al. introduced an innovative ultrasonic testing methodology in their recent study.
✔️Results from Ultrasonic Cycling Tests:
The researchers conducted a cycling test, a standard procedure in battery health studies where the battery undergoes successive charging and discharging. The results yielded significant insights. For instance, a Battery showed a consistent decline in SOH with the progression of cycles. The TOF readings, in particular, demonstrated a robust correlation with battery degradation, showcasing their potential as a primary SOH metric. However, the PA readings were less predictable, thus highlighting the need for cautious interpretation.
Under abusive testing conditions, where the battery experienced intentional overcharging, the shifts were even more pronounced. There was a marked increase in temperature, visible swelling, and an abrupt rise in the TOF. Such findings suggest the onset of gas generation and increased layer thickness within the battery are red flags for deteriorating battery health.
While the TOF emerges as a standout metric, it becomes evident that its full potential is realized when ultrasonic data is harmoniously amalgamated with other monitoring parameters, such as temperature. As our reliance on LIBs intensifies, pioneering monitoring methodologies like this will be pivotal in assuring both efficiency and safety.
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