Winding is the method for forming the cells of cylindrical batteries and prismatic aluminum-shell batteries. A wound cell refers to a battery core in which positive and negative electrode sheets, in the form of material rolls or long sheets with a layer of separator sandwiched between them, are wound together into a cylindrical or prismatic battery core. It is one of the key processes in completing lithium-ion battery manufacturing. Winding control is further divided into circular winding and prismatic winding according to the shape of the winding needle.