Quality inspection of battery slurries

Eddy-current and ultrasound technology can be applied to liquid materials, too. An example for this is the monitoring of quality properties of battery slurries during mixing and formation in a ballmill. For this application, the high-frequency EddyCus® eddy-current and PCUS® ultrasonic technology of Fraunhofer IKTS was customized for the Korean partner NANOINTECH Co. Ltd. 

For this purpose, a new sensor with integrated eddy current coils and ultrasonic transducers was developed and assembled into a robust probe for harsh environmental conditions. The system can then be installed directly in the process flow of a ballmill or in an offline device.

Experiments within a ballmill show the huge potential of the non-destructive inspection system. Time-dependent sensor parameters in the eddy-current and ultrasonic domain correlate well with the material properties. The combination of both techniques extends the capability from low conductive to isolating materials. Mechanical properties can be analyzed by the use of reflection and transmission ultrasound. At high frequencies above 20 MHz, the EddyCus® technology can recognize material deviations even in isolator materials, such as Al₂O₃ slurries. Changes in the speed of sound and frequency spectrum of the ultrasonic signal over time correlate with slurry density and particle size distribution.

The combined technology can either be installed inline into existing mixing machinery, or it can be used offline in laboratory environment. It gives customers the ability to control the quality of their liquid products. Fraunhofer IKTS is currently setting up an anonymized data room, which collects the data of all installed systems. This dataset will be used to train a model based on machine learning methods, with the aim to develop universal inspection recipes for unknown materials.

Services offered

• Evaluation of unknown battery slurries
• Offline monitoring of existing battery slurry mixing processes
• Integration of the measuring system into existing mixing machinery