After laser cutting the pole piece, through the rotation of the needle, the pole piece is rolled into a layer on layer covering the core shape, the normal way of covering the diaphragm, positive electrode, diaphragm, negative electrode. Generally, there are round and oval needles. Theoretically, the rounder the needle is, the better the coil core fits, but the round needle makes the pole ear turn over seriously. In the process of winding, CCD is used to detect and correct the distance between positive and negative electrodes, and the distance between positive and negative electrodes and diaphragm.
The diaphragm plays the role of separating the positive and negative electrodes, preventing the internal short circuit of the battery, allowing the free passage of electrolyte ions, and completing the electrochemical charge and discharge process.