Lithium battery pack manufacturers analyze the thermal shaping process of soft pack lithium-ion batteries

In the production of lithium-ion batteries, after the production of the pole pieces is completed, the positive and negative plates and the separator of the lithium-ion battery will be assembled into batteries by a winding or lamination process, and then the batteries will be hot-pressed to form the lithium battery. PACK factory briefly introduces the main points and purpose of these processes. 1. The purpose of the process, whether it is winding or Z-type lamination, the diaphragm will generate tension, and the tape will be elongated during the process, resulting in an increase in the shrinkage of the diaphragm in the tape direction, and the diaphragm will be squeezed at this time The pole piece, the battery cell will be deformed, the appearance of the deformed battery cell will be poor, and there will be wrinkle defects inside the diaphragm, and the finished lithium-ion battery will have low capacity, poor cycle performance, and unqualified self-discharge. This phenomenon is particularly obvious in the winding process, and the consistency of the battery core will also deteriorate. It will also increase the difficulty of the battery core into the shell. Hot pressing has two main purposes: 　　1) Improve the flatness of the surface of the lithium ion battery, improve the quality of the cell, and make the cell size and other parameters highly consistent; 　　2) Eliminate the wrinkles of the diaphragm and squeeze out the internal gas , Make the diaphragm and the positive and negative pole pieces close together, shorten the lithium ion diffusion distance, and reduce the internal resistance of the battery.　　 2. The hot pressing and shaping process of the electric core is as follows: Put the electric core to be processed on the template, set the pressure of the booster cylinder and the temperature of the template, so that the electric core is formed under a certain temperature and pressure.　　 During the hot pressing and shaping of the cell, the insulation withstand voltage test is performed on the cell at the same time to detect whether there is a micro short circuit inside the cell.　　3. Process points 　　The main process parameters of the hot-pressing and shaping of the electric core are pressurizing pressure, pressurizing time and template temperature. Under appropriate process parameters, there is almost no air inside the thick battery cell, the diaphragm and the pole piece are tightly bonded together, and the loose battery core can become a hard block. The diaphragm is the core component of the battery. It isolates the electron conduction between the positive and negative electrodes of the lithium battery, and at the same time allows lithium ions to pass back and forth between the two electrodes. The microporous structure on the diaphragm is an important channel for these ions to travel between the positive and negative electrodes. The air permeability will directly affect the performance of the battery. If the air permeability of the separator is not good, it will affect the conduction of lithium ions between the positive and negative electrodes and affect the charge and discharge of the lithium battery. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Can the ER34615 lithium battery be recharged after it runs out?