3.7v 18650 lithium battery

　　18650 lithium-ion battery pack production process

　　(1) Baking

　　Bake for 12 hours under the condition of constant temperature and vacuum degree of -0.09MPa. The main purpose is to dry the moisture of the battery cell.

　　(2) Injection

　　Inject the battery cell after vacuum baking into the electrolyte solution in the glove box filled with Ar gas. The amount of liquid injection is different according to the design of the lithium-ion battery pack. Use this to judge whether the injection volume is appropriate or not.

　　(3) Welding tabs Weld the positive tab (aluminum strip) and the negative tab (nickel strip) to the scraper positions of the positive and negative tabs with an ultrasonic welding machine. Pay attention to prevent welding deviation, welding dislocation, and false welding.

　　(4) Bottom welding. First put the insulating gasket into the steel shell, then put the wound battery core into the steel shell, and weld the negative tab to the bottom of the steel shell with a spot welder. Check the outer surface of the bottom of the steel shell, pick out yellow spots, black spots, defects, fires and other poor appearances, and try to pull the tabs, pick out 18650 lithium-ion battery packs that are not firmly spot welded, such as fires, weak welding, and desoldering.

　　(5) sealing

　　First spot weld the steel shell and cap of the 18650 lithium-ion battery pack with a spot welder, and then continue laser welding with a laser welder. Laser welding should ensure accurate positioning, and the welded parts are clean. It is strictly forbidden to cause deformation or damage to the battery. Check after welding, and repair welding for defective batteries such as welding holes and explosions.

　　(6) Winding

　　Put the ion-exchange membrane on the winding needle evenly, and the front end protrudes 2-5mm from the winding needle. There should be no wrinkles at the four corners of the pole piece. If the adhesive tape is misaligned left and right, the adhesive tape does not cover the solder joints and other defects, the positive electrode material must hug the negative electrode material, the electrode sheet cannot be rolled, and the front end of the electrode sheet must be inserted to the top.

　　18650 lithium-ion battery assembly method

　　1. The 18650 lithium-ion battery packs are neatly arranged, which is convenient for maintenance in the future. It is best to use a standard 18650 battery card tray;

　　2. The welding is good. The most common welding method on the market is spot welding with a nickel welding machine. An electric soldering iron can also be used, and the solder joints are in good contact;

　　3. After welding, the lines of each battery group must be clear;

　　4. Do a good job of waterproofing and insulation. It is best to cut a piece of highland barley paper or use asbestos material;

　　5. The most important point is that the internal resistance of the battery before welding, and the current voltage error should not exceed 0.05V! If conditions permit, a special protection board for 18650 lithium-ion battery pack must be added to prevent overcharging and over-discharging;

　　6. After welding, measure whether the voltage of each circuit is good;

　　7. After the newly assembled lithium-ion battery pack has been used for a period of time, it is necessary to check the voltage of the battery in groups.