The full inspection of misalignment of the core and pole pieces is a key quality inspection process for lithium-ion batteries after winding, aiming to detect 100% of defective cells caused by winding process deviations where the negative electrode piece fails to completely wrap around the positive electrode piece (i.e. "misalignment"), fundamentally eliminating the risk of internal short circuits caused by hair piercing through the separator.

The standard automated testing process includes the following three core steps:

Automatic feeding and positioning: The robotic arm accurately grasps the core to be inspected from the conveyor belt and places it in the rotating fixture. The fixture fixes the core and drives it to rotate precisely through a servo motor, so that the entire circumferential side of the core enters the field of view of the visual inspection system in sequence.

Image acquisition and intelligent analysis: A high-resolution CCD camera, combined with a specific angle of light source (such as backlight), takes high-speed continuous photos of the rotating core side to obtain clear images of the edge of the polarizer stack. The image processing system uses advanced algorithms to accurately identify and measure the edge positions of the positive electrode, negative electrode, and separator, and calculates the alignment degree (Δ value) between the two electrodes in real time.

Automatic discrimination and sorting: The system compares the real-time measured misalignment with the preset process tolerance range. The core judged as "qualified" is grasped by a robotic arm and flows into the next process; And the cores judged as "unqualified" (misaligned and out of tolerance) are automatically removed to the waste bin, achieving fully automatic online sorting.

The core value of this process lies in replacing inefficient and easily missed manual visual inspection with non-contact, fully automated visual inspection, achieving objectivity, standardization, and dataization of quality judgment. It can intercept all misplaced defective products from the source, which is a key quality barrier to improve battery safety and production yield.