Decoding Sounds of Lithium-Ion Battery Failures

Understanding Acoustic Emissions in Lithium-Ion Batteries

Lithium-ion batteries produce faint sounds as they charge, discharge, and degrade. But until recently, nobody could interpret these sounds to predict battery performance issues such as power loss, failure, or even fire hazards.

Breakthrough at MIT

Engineers from MIT have developed a method to decode these acoustic emissions, even amid noisy data environments. The findings lay the groundwork for developing simple, passive, nondestructive devices capable of continuously monitoring battery health across various applications, including electric vehicles and large-scale grid storage.

Key Mechanisms of Battery Degradation

As noted by Martin Z. Bazant, professor of chemical engineering and mathematics, "Through some careful scientific work, our team has managed to decode the acoustic emissions." The team classified these sounds, which originate from gas bubbles created by side reactions or fractures from the expansion and contraction of active materials—two primary mechanisms leading to degradation and failure.

Research Methodology

The research team coupled electrochemical testing of operational batteries with recordings of their acoustic emissions. They utilized advanced signal processing techniques to correlate sound characteristics with voltage and current metrics. Subsequently, they dismantled the batteries to examine them under an electron microscope for fracturing.

Early Warning Signals for Safety

In collaboration with Oak Ridge National Laboratory, the researchers demonstrated that acoustic emissions can serve as an early warning system for gas generation, a precursor to thermal runaway events that can result in fires. Bazant likened this to "seeing the first tiny bubbles in a pot of heated water, long before it boils."