High-Throughput Terahertz Scanning for Quality Assessment of Battery Electrode Manufacturing

Laboratory and the University of California, Irvine (UCI) Zenyuk Laboratory, is pioneering a transformative solution to address a critical need in lithium-ion battery (LIB) manufacturing: an in-line, real-time, non-contact, non-destructive evaluation (NDE) instrument for LIB electrodes. This instrument aims to revolutionize the quality control (QC) process by detecting defects in LIB electrodes during the early stages of production. The demand for LIBs has experienced exponential growth, especially in the electric vehicle (EV) market, owing to their high energy capacity and density. Despite the rising demand, the cost of LIBs remains a significant obstacle to widespread adoption. Efforts to reduce costs and improve quality have been ongoing for decades. One major challenge is the current scrap rate during production, leading to increased manufacturing costs. Flaw detection is critical to prevent flawed electrodes from being integrated into battery cells, as defects can result in diminished performance, safety hazards, and higher costs. Several NDE techniques have been explored for in-line QC of LIB electrodes, including X-ray fluorescence, X-ray computed tomography, infrared thermography, and optical imaging. However, these techniques have limitations such as slow scanning speed, limited field of view, and safety hazards. Electrical testing and ultrasound imaging can only detect defects at late manufacturing stages. Therefore, there is a critical need for a practical NDE instrument that can evaluate electrode integrity at early production stages. The proposed solution from Lookin, Inc. addresses these shortcomings by employing terahertz technology, which offers unique advantages for QC applications. Terahertz waves can penetrate opaque materials and interact with hidden structural features without posing health hazards. Pulsed terahertz imaging systems are particularly promising for QC applications, offering time-of-flight imaging to identify defects and coating thickness variations. However, conventional terahertz imaging systems face limitations such as limited signal-to-noise ratio (SNR) and slow scanning speed. Lookin, Inc. aims to overcome these limitations through three key innovations: the use of plasmonic terahertz source and detector technology to enhance SNR, terahertz focal-plane array technology to increase field of view and scan throughput, and an advanced data analysis framework empowered by machine learning to improve defect detection capabilities. During the Phase I program, a laboratory prototype of the terahertz scanner was developed and successfully tested for defect detection on LIB electrodes. Encouraged by these results, Lookin, Inc. proposes to continue development in Phase II by building a field prototype and testing it at LIB manufacturing facilities. Integration into the prototype line of battery manufacturing facilities at General Motors and LG Energy Solution will demonstrate the system's field feasibility and provide data to further improve data analysis algorithms. By enabling in-line detection of LIB electrode defects during production, Lookinĺs terahertz scanners can be an invaluable instrument for LIB manufacturers.