Optically-Coupled X-Ray Computed Laminography System for High-Speed Inspection of Lithium-Ion Batteries

Conventional X-ray computed tomography systems for microstructure inspection typically employ a geometrically magnified imaging setup, requiring a micro-focus X-ray source to mitigate image blurring caused by a finite focal spot size. However, due to its low output power, the micro-focus X-ray source results in prolonged image acquisition times. This study presents a novel optically-coupled X-ray computed laminography system for high-speed inspection. In the proposed system, a scintillator is placed in contact with an object, effectively minimizing image blurring despite the use of an X-ray source with a large focal spot. Consequently, a high-power X-ray tube can be employed without compromising spatial resolution, leading to a significant reduction in scan time. Modulation transfer function analysis confirms that a spatial resolution of 38 µm is achieved using a high-power (400 W) X-ray tube with a 400 µm focal spot. In addition, high-quality 3D imaging of lithium-ion batteries (LIBs) is demonstrated with a scan time as low as 2 s and a contrast-to-noise ratio exceeding 3. By overcoming the trade-off between the spatial resolution and the scan time in X-ray imaging, the proposed system enables high-throughput in-line inspection of mass-produced LIBs.