Real Time Ultrasonic Monitoring of Solid-State Lithium-Ion Cells in the Frequency Domain

The widespread use of lithium-ion battery technology for energy storage has created a need for accurate, real-time, state of charge and health monitoring. Most existing methodologies cannot access the electrochemical processes directly, often relying on inference into the internal states through proxy measurements, leading to increased predictive errors in remaining cell life and capacity. The proposed research uses noninvasive ultrasound applied to solid-state cells over a range of frequencies in the low megahertz to infer the intercalaction levels of the electrodes, bypassing the need for terminal voltage or current measurements. The preliminary experiments have shown a correlation between the charge state and acoustic phase changes with fixed distance transducers bonded to the battery surface.