Meaning
Non-destructive evaluation techniques use high frequency sound waves to visualize the internal structure and electrolyte distribution within a finished battery cell. Using ultrasonic transmission mapping allows technicians to see through the opaque casing and identify hidden defects like gas bubbles or delaminated layers. The method is effective for flat pouch or prismatic cells but is more difficult to apply to complex curved geometries.
Wave Propagation
Sound energy travels at different speeds through the solid and liquid phases of a battery. During ultrasonic transmission mapping, a transducer sends a signal through the cell while a receiver captures the attenuated wave on the other side.
Defect Identification
Voids and dry spots reflect the sound waves and create dark areas on the resulting image. Analyzing the data from ultrasonic transmission mapping reveals whether the electrolyte has fully wetted the separator and the electrode surfaces. Early detection of these wetting issues prevents the assembly of cells that would fail prematurely.
Production Integration
Automated scanning systems can inspect hundreds of cells per hour on a high volume line. Implementing ultrasonic transmission mapping provides a real time feedback loop for adjusting the electrolyte filling and vacuum sealing processes. High resolution maps help researchers study how the internal structure of the cell changes during hundreds of charge and discharge cycles.
This imaging technique is a powerful tool for improving the consistency and reliability of advanced energy storage systems.
