The pre-stacking vision inspection station, a critical in-line quality control unit integrated into a fully automatic lithium-ion battery electrode stacking production line. This station is purpose-engineered to perform comprehensive, high-speed quality validation of individual battery electrode sheets before they enter the core lamination process, effectively preventing defective components from flowing downstream and safeguarding the final battery cell’s dimensional consistency, electrical performance and long-term safety.
At the center of the station lies a precision inspection platform fitted with a uniform high-brightness white LED backlight system. When a thin, precision-cut electrode sheet is positioned on this backlit surface, the transmitted light sharply defines the full outer contour of the electrode and its attached electrode tabs, creating high-contrast, shadow-free imaging conditions that maximize the accuracy of machine vision detection. Mounted directly above the inspection zone are two high-resolution industrial area-scan cameras, paired with precision optical lenses to capture fine-grained images of the entire electrode sheet at production-line speeds. Powered by dedicated machine vision processing algorithms, the system performs real-time, pixel-level analysis on the captured imagery: it identifies a full spectrum of appearance and geometric defects including edge chipping, material loss, micro burrs, dimensional deviations and overall shape incompleteness on the electrode body, as well as tab-related abnormalities such as missing tabs, positional offset, bending, folding, tearing and surface damage.
Beneath the backlight inspection platform, an ultrasonic detection sensor is embedded to verify the exact number of electrode sheets present on the station. Leveraging the measurable difference in ultrasonic wave penetration and reflection across single and multiple stacked layers of electrode foil and coating material, the sensor can accurately distinguish between a single qualified sheet and accidental multi-sheet overlapping. This function eliminates the risk of double-sheet or multi-sheet misfeeding into the stacking process, which would otherwise cause out-of-tolerance cell thickness, internal short circuits or other severe hidden quality hazards in the finished battery cell.
The entire inspection workflow operates fully automatically and in tight synchronization with the line’s material handling system — the vacuum suction pickup mechanism visible in the upper portion of the image is responsible for loading and transferring electrode sheets to and from the inspection station. Only when an electrode sheet passes all inspection criteria — including appearance integrity, tab geometry quality and single-sheet verification — will the central control system issue a clearance signal, and the handling mechanism will transfer the qualified sheet onward to the subsequent automatic Z-stacking process for cell assembly. Any electrode sheet that fails any inspection item will be automatically sorted into a dedicated rejection bin as non-conforming product.
This integrated optical and ultrasonic pre-inspection design significantly improves the overall first-pass yield of the electrode stacking process, reduces scrap costs in downstream assembly steps, and has become a standard quality control configuration for high-automation lithium-ion battery production lines serving consumer electronics, power tools and new energy mobility applications.