Development of a Non-Destructive Ultrasonic Technique for In-Situ Battery Health Monitoring

An in-situ structural health monitoring technique for the safe operation of Lithium-Ion Battery (LIB) using Rayleigh-Lamb wave is reported herein. While the LIBs are important because of their high energy density, long cycle life, fast charging, low self-discharge rate, and environmental friendliness, they also come with safety concerns. Even though LIBs are electrochemical devices, their structural integrity must be maintained for its safe operation. Whenever a LIB operates outside of its safe operating limits, the structural integrity gets disrupted, and its performance drops significantly. This can lead to challenges such as a rise in internal resistance or temperature which may eventually lead to thermal runway. While the battery management systems (BMS) can take care of some preventive measures, such as overcharge/discharge protection, an effective in-situ sensing system to monitor battery internal structures is currently non-existent. While X-ray tomography, Neutron imaging or Electron microscopy can provide internal images, these off-situ techniques are nonconventional to integrate with the BMS. To circumvent these issues, a non-destructive ultrasonic guided wave-based acoustic technique is experimentally developed herein. In particular, the battery state of charge (SoC) in terms of voltage level is determined by analyzing ultrasonic transmission (UT). Also, the correlation between surface temperature and UT is established.