Why do rechargeable steel button batteries use laser welding technology?

In recent years, with the explosion of TWS earphones, new rechargeable button batteries with advantages such as high endurance, high security and personalization have been unprecedentedly popular in various small wearable devices such as TWS earphones, smart watches, smart glasses and smart speakers.

Button cell, also known as button cell, has the greatest advantage of good consistency and will not bulge during the charging and discharging cycle. It can set a larger battery capacity and directly attach to the PCB. The new rechargeable button battery realizes fast charging technology and meets the needs of some special application equipment. It is not only environmentally friendly, but also can be recharged repeatedly.

With the in-depth development of 3C electronic industry, customers put forward higher requirements on battery safety, followed by higher requirements on production process and production line equipment. Therefore, most rechargeable steel shell button batteries on the market are produced using laser welding technology. Why should rechargeable steel shell button batteries use laser welding technology

First of all, let's learn about the application processes of button battery laser welding?

1. Shell and cover plate: laser etching of button steel shell;

2. Electric core section: welding the positive and negative poles of the coil core with the shell cover, laser welding the shell cover with the shell, and welding the sealing nails;

3. PACK section of module: electric core screening, side pasting, positive and negative electrode welding, post welding inspection, size inspection, upper and lower adhesive tapes, air tightness inspection, blanking sorting, etc.

Why do rechargeable steel button batteries use laser welding technology?

1. It is difficult for traditional welding processing technology to meet the high standard welding indicators of the new rechargeable button battery. In contrast, laser welding technology can meet the diversity of button battery processing technologies, such as welding of different materials (stainless steel, aluminum alloy, copper, nickel, etc.), irregular welding tracks, more detailed welding points, and more accurate positioning welding areas, which not only improve the product welding consistency, It also reduces the damage to the battery during welding, and is the best welding process for button battery at present.

2. When the positive and negative electrodes of the electric core are welded with the shell cover, the copper material has good conductivity, but the high reflective material has very low laser absorption rate. In addition, the material is extremely thin, which can easily deform when the heating area is too large, the heating time is too long, or the laser power density is not enough, resulting in poor welding.

When the top cover is sealed and welded, the thickness of the connection between the button battery shell and the cover plate after processing is only 0.1mm, which cannot be realized by traditional welding. If the laser welding power is too high, the battery shell will be directly broken down, and the internal electric core will be damaged, and the material is very easy to deform. If the power is low, the welding pool cannot be formed to achieve the purpose of welding.

Pin and finished battery are usually realized by overlapping penetration welding. During this welding process, the battery has been sealed and filled with electrolyte. If the welding process is unstable, it is easy to cause internal diaphragm welding damage and short circuit, or the battery shell is welded through, resulting in electrolyte outflow, faulty welding, over welding and other undesirable phenomena.

3. Laser welding technology is applicable to the automatic assembly, welding and manufacturing of steel shell button battery; Modular design, compatible with 8-16mm button battery cell assembly and manufacturing, to achieve traceability of production line data.

4. The laser welding technology equipment can upload the data from the electric core screening to the whole set of processes such as the fitting accuracy control and welding energy detection in the welding process, so as to realize the fully automatic assembly welding and ensure the efficient output of products; High precision laser fit welding technology, real-time monitoring technology in welding, and visual size sorting technology ensure high-quality welding while giving consideration to high-precision size control, with higher reliability and stability, and the welding excellence rate reaches 99.5%.