18650 Lithium Battery Manufacturing Process.

Electrode lug

Weld the positive electrode lug (aluminum bar) and negative electrode lug (nickel bar) on the scraper of positive and negative electrodes with ultrasonic welding machine. Pay attention to prevent welding deviation, misplacement and false welding.

Winding

Place the ion-exchange membrane flat on the winding needle, and the front end protrudes 2-5mm from the winding needle. The four corners of the electrode sheet shall be free of wrinkles, the electrode sheet shall not fall off, the adhesive tape shall be inclined, the single-sided adhesive tape shall be too long, the double-sided adhesive tape shall be staggered left and right, the adhesive tape shall not cover the solder joint and other defects. The positive material must hold the negative electrode material, the electrode sheet shall not be rolled off, and the front end of the electrode sheet must be inserted to the top.

Check the winding defects: the ion exchange membrane is not complete, that is, the positive and negative poles exceed the exchange membrane; High slice and low slice; The pole piece is not put in place, the positive end of the outer ring does not hold the negative end, and the positive and negative pole pieces of the inner ring do not overlap with the top of the exchange membrane, there is still a distance; The negative electrode tail of the exchange membrane shoe is too tight; The positive aluminum strip and negative nickel strip are longer and shorter; Poor adhesive tape at the end of battery cell; The battery cell is not rolled in place: the distance between the positive and negative electrode lugs is too wide or narrow; The exchange membrane is not flattened and wrinkled; Positive crimping; The positive plate has no curled angle or missing angle; The exchange membrane does not fully embrace the negative electrode tail; The inner and outer electrode plates are misaligned.

Underwelding

First put the insulating gasket into the steel shell, then put the wound electric core into the steel shell, and use the spot welder to weld the negative lug at the bottom of the steel shell. Check the external surface of the bottom of the steel shell, pick out the cells with poor appearance such as yellow spots, black spots, defects and explosion, and try to pull the lug, pick up the batteries with unstable spot welding such as explosion, faulty welding and desoldering.

Sealing

First, spot weld the steel shell and cap of the battery with a spot welder, and then use a laser welding machine for continuous laser welding. Laser welding shall ensure accurate positioning, clean parts to be welded, and it is strictly prohibited to cause deformation or damage to the battery. Check after welding, and repair welding shall be carried out for bad batteries such as welding holes and explosions.

Baking

Bake for 12 hours under the condition of constant temperature and vacuum degree of -0.09MPa, mainly to dry the moisture of the cell.

Liquid injection

Inject electrolyte into the glove box filled with Ar gas after vacuum baking. The liquid injection amount varies according to the battery design. Weigh the battery before and after liquid injection. The weight difference is the liquid injection amount to judge whether the liquid injection amount is appropriate.

Shenzhen Topband Battery Co., Ltd.，established in 2006, is a wholly-owned subsidiary of Shenzhen Topband Co., Ltd. (002139.SZ). We focus on lithium iron phosphate batteries,with independent research and development in cells and BMS. With the ability to integrate the entire industry chain, we are committed to providing customers with one-stop lithium battery solutions and services. Our quality products are widely used in energy storage and light power.