Winding Process 1. Principle and Process Principle: The winding process involves the use of a fixed winding needle to wind and compress the pre-processed anode sheets, separator, and cathode sheets in sequence to form a cylindrical or elliptical shape. Process: The raw materials are stacked in the sequence of anode, separator, cathode, separator. Then, they are wound into cylindrical or elliptical shapes and placed into metal casings, either square or cylindrical. Specific steps include the unwinding of the anode and cathode sheets and separators, automatic alignment, automatic tension detection and control. The anode and cathode sheets are fed into the winding section by a clamp feeding mechanism, which, together with the separator , undergoes automatic winding according to specified process requirements. After the winding is completed, the machine automatically switches workstations, cuts the separator, attaches the end seal tape, and the finished bare cell is automatically dis...
Preface Formation is a critical step in the production process of lithium-ion batteries. The primary purpose of formation is to generate a solid electrolyte interphase (SEI) on the surface of the anode, which serves to isolate electrons while allowing ion conduction. The quality of the SEI formation directly affects the subsequent cycling performance of the battery. Therefore, controlling appropriate formation conditions (such as formation temperature, charging rate, applied pressure, etc.) is a crucial production step. The SEI formation process is accompanied by an increase in the volume of the battery. This increase is attributable to two main factors: the gaseous byproducts generated during the film formation reaction and the expansion of the anode structure as lithium ions are extracted from the cathode and intercalate into the anode. In this study, in-situ volume monitoring instruments (GVM) are employed to conduct in-situ volume testing of NCM523/graphite cells (theoretic...