Post manufacturing process and control points of 18650 battery.

Post manufacturing process and control points of 18650 lithium battery.

The post manufacturing process of batteries includes liquid injection, welding, sealing, cleaning, and film coating. Liquid injection refers to the process of injecting electrolyte into the baked core with qualified moisture requirements through a liquid injection machine. After the liquid injection is completed, the four main materials of the lithium battery are all applied to the core. The key to the liquid injection process is to precisely control the amount of liquid injection, humidity control, temperature control, and waterproofing, and to achieve the effect of good infiltration and penetration of electrolyte into the positive and negative electrode pieces. The amount of electrolyte directly affects the safety performance and capacity of the battery. If the injection volume is too high, the internal gas production of the battery will be large, and the safety valve of the cylindrical battery will often open prematurely; If the injection volume is too small, the battery capacity will be low and lithium will precipitate, which is more likely to cause thermal runaway or even explosion. Then weld the cover plate and the positive electrode ear together, and the entire cover plate becomes the positive electrode of the battery. The control point of welding is to prevent virtual welding, deviation welding, and poor appearance of the cap.

The next process is sealing, which seals the steel shell and cover plate, isolating the entire core from the external environment. The entire core is a sealed electrochemical system. The sealing process is the last crucial step in the entire battery cell manufacturing process, and the stability of its pressure forming technology determines whether the battery's sealing is intact and reliable. Completing the sealing process means that the manufacturing of a fully formed battery cell has been completed. The purpose of the cleaning process is to remove the residual electrolyte on the surface of the battery steel shell, prevent the electrolyte from corroding the steel shell, while the coating process is to ensure that the positive and negative terminals of the battery cell are separated, prevent external circuit short circuits, and give the battery a certain degree of aesthetics. These two processes also require screening for batteries with poor appearance.