How is the battery made

1. (Positive and negative electrode) dry mixing → wet mixing → rolling paste on conductive substrate → 3 step drying → winding → trimming (cut to a certain width) → rolling → winding (standby) dry mixing using ball mill , The grinding ball is a glass ball or a zirconia ceramic ball; it is used for wet mixing. The planetary powder mixer, the blades are installed on 2-3 shafts, and the mixing effect is better. The amount of solvent in the wet mixing should be appropriate to form a proper rheological state to obtain a smooth coating. Roll-coated electrode paste must ensure a certain viscosity. The paste is applied to both sides of aluminum foil or copper foil, and the thickness of the coating depends on the battery model. Then it passes through 3 heating zones for drying. NMP (or water) volatilizes from the coating with the flow of hot air or dry nitrogen, and the solvent can be recycled and reused. Rolling is to increase the density of the coating and to make the electrode thickness meet the size of the battery assembly. The pressure in the rolling stage should be moderate to prevent the powder from scattering during winding. 2. The assembly process of the battery. The assembly process of the cylindrical battery: the insulating bottom ring into the barrel → winding the cell into the barrel → inserting the mandrel → welding the negative current collector to the steel barrel → inserting the insulating ring → rolling the steel barrel → vacuum drying → Injecting liquid→welding the combined cap (PTC element, etc.) to the positive electrode lead→sealing→X-ray inspection→number→formation→circulation→ageing. Square battery assembly process: insulating bottom into the steel box → sheet-shaped combined cell into the barrel → negative current collector welded to the steel box → upper sealing gasket → positive current collector welded to the pole lead → combined cover (PTC components, etc.) Weld to the screw lead → position the combined cover → laser welding → vacuum drying → liquid injection → sealing → X-ray inspection → numbering → formation → circulation → aging. Assembly process description: Take a cylindrical battery as an example (the basic process of a square battery is the same). Before winding the core into the barrel, the aluminum strip (0.080.15 mm thick, 3 mm wide) and nickel strip (0.040.10 mm thick, 3 mm wide) are ultrasonically welded to the designated places of the positive and negative conductive substrates as a set. Flow priming. The battery diaphragm is generally composed of PE/PP2 layer or PP/PE/PP3 layer, and the diaphragm is heat-treated at 120°C to increase its resistance and improve its safety. The positive electrode, the separator, and the negative electrode are wound into the cylinder after being superimposed. Because the paste electrode is used, the paste material must be well combined with the substrate to form a high-density electrode. In particular, it is necessary to prevent the powder from falling to prevent it from penetrating the separator. This causes a short circuit inside the battery. Before the winding cell is inserted into the steel cylinder, put an insulating bottom into the bottom of the steel cylinder to prevent the internal short circuit of the battery. This is the same for general batteries. Electrolytes generally use LiPF6 and non-aqueous organic solvents. Before vacuum injection, the battery should be vacuum dried for 24/h to remove water and moisture in the battery components, so as to prevent LiPF6 from reacting with water to form HF and shorten the life. The battery sealing adopts the process of applying sealant, inserting the gasket, crimping and shrinking the section. The basic principle is the same as that of an alkaline rechargeable battery. After sealing, the battery should use a mixture of isopropanol and water to remove oily dirt and spilled electrolyte, and then dry. Use an odor sensor or sniffer element to check for battery leakage. After the entire battery assembly is completed, the battery should use X-rays to identify whether the internal structure of the battery is normal. Check for abnormal battery cores, cracks in the steel shell, solder joints, and short circuits to eliminate the above-mentioned defective batteries to ensure the quality of the battery. The last process is formation. The battery is charged for the first time, and a protective film is formed on the anode, which is called a solid electrolyte interphase layer (SEI). It can prevent the anode from reacting with the electrolyte and is the key to safe operation, high capacity, and long life of the battery. Elements. After several charge-discharge cycles, the battery is aged for 23 weeks, the micro-short-circuit battery is removed, and the capacity is sorted and packaged, and then it becomes a commodity. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: What are the requirements for the packaging of the customer’s battery?