1. Welding of battery explosion-proof valve

The explosion-proof valve of the battery is a thin-walled valve body on the battery sealing plate. When the internal pressure of the battery exceeds the specified value, the valve body of the explosion-proof valve ruptures to prevent the battery from bursting. The safety valve has an ingenious structure, and this process requires extremely strict laser welding technology. Continuous laser welding can achieve high-speed and high-quality welding, and welding stability, welding efficiency and yield can be guaranteed.

2. Welding of battery tabs

The tabs are usually divided into three materials. The positive electrode of the battery uses aluminum material, and the negative electrode uses nickel material or copper nickel-plated material. In the manufacturing process of power batteries, one of the steps is to weld the battery tabs and poles together. In the production of the secondary battery, it needs to be welded with another aluminum safety valve. Welding must not only ensure the reliable connection between the tab and the pole, but also requires a smooth and beautiful weld.

3. Spot welding of battery poles

The materials used for the battery poles include pure aluminum tape, nickel tape, aluminum-nickel composite tape, and a small amount of copper tape. The welding of battery electrode strips generally uses pulse welding machines. Due to its good beam quality and small welding spot, Modulated CW lasers or QCW quasi-continuous lasers are suitable for high reflectivity aluminum strips, copper strips and narrow-band battery strips (polar strip width (Under 1.5mm) welding has unique advantages.

4. The power battery shell and the cover plate are sealed and welded

The shell materials of the power battery are aluminum alloy and stainless steel (stainless and acid-resistant steel). Among them, aluminum alloy is mostly used, generally 3003 aluminum alloy, and a few use pure aluminum. Stainless steel is a laser weldable material, especially 304 stainless steel, whether it is pulsed or continuous laser, it can obtain welds with good appearance and performance.

5. Power battery module and pack welding

The series and parallel connections between power batteries are generally completed by welding the connecting piece and the single battery. The positive and negative electrodes are made of different materials. Generally, there are two kinds of materials: copper and aluminum. Ultrasonic welding was usually used before, but its being replaced by laserwelding due to the regulary mechanical damage in the battery resulting from the ultrasonic vibrations. Copper and copper, aluminum and aluminum are generally used. Using laser welding. Both copper and aluminum conduct heat very quickly and have a very high reflectivity to the laser. The relatively large thickness of the connecting piece requires a higher power laser welding.