In recent years, with the popularity of TWS earphones, the new rechargeable button battery with the advantages of high endurance, high security, and personalization has become unprecedentedly popular and has been widely used in various small wearable devices such as TWS earphones, smart watches, smart glasses, and smart speakers.

The button cell is also called the button battery. The biggest advantage is that it has good consistency and will not bulge during the charge-discharge cycle. It can set a larger battery capacity and directly fit to the PCB. The new rechargeable button battery can realize fast charging technology and meet the needs of applications for some special equipment. It is not only environmentally friendly, but also can be recharged and used repeatedly.

With the in-depth development of the consumer electronics industry, customers have put forward higher requirements for battery safety, and subsequently put forward higher requirements on production technology and production line equipment. It is difficult for traditional welding processing technology to achieve the high standard welding index of new button batteries. In contrast, laser welding technology can meet the processing technology diversity of button batteries.

For example,  it can fulfill the welding of dissimilar materials (stainless steel, aluminum alloy, copper, nickel, etc.) with irregular welding trajectories, more detailed welding spots, and more precise positioning of welding areas. It can improve the welding consistency of products and reduce the damage caused to the battery during the welding process. And it is the best welding process for button batteries at present.

Button Battery Laser Application Process

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

2. Cell section: welding the positive and negative electrodes of the winding core and the shell cover, laser welding of the shell cover and shell, and welding of seal pins;

3. Module PACK section: cell screening, side gluing, positive and negative electrode welding, post-weld inspection, dimensional inspection, upper and lower tapes, air tightness inspection, unloading and sorting, etc.

Difficulties in Welding and Assembly of Button Batteries

When the positive and negative electrodes of the winding core are welded to the shell cover, the copper material has good conductivity. But the high reflective material has a low laser absorption rate, and the material is extremely thin. The heating area is too large, the heating time is too long, or the laser power density is small, which is easy to deform and result in poor welding.

When the top cover is sealed and welded, the thickness of the connection between the button battery case and the cover plate is only 0.1mm after processing, which cannot be achieved by traditional welding. If the laser welding power is too large, it will directly break down the battery case, damage the internal cells, and the material will be easily deformed.

The lead and the finished battery are usually achieved by penetrating welding in a superimposed manner. When this welding process is performed, the battery is encapsulated and filled with electrolytes. If the welding process is unstable, it is easy to cause the internal diaphragm to be damaged and cause a short circuit or the battery shell to be welded through, resulting in electrolyte outflow and virtual welding. , over-welding, and other undesirable phenomena.

Aiming at the above-mentioned dilemmas of button battery welding and intelligent manufacturing, UW Laser is positioned as a world-class provider of laser welding equipment and intelligent manufacturing solutions and has carried out a series of positive technological upgrades following the trend. It has also explored the industry-leading intelligent manufacturing of button battery equipment and solutions that been applied and appreciated by many customers.

UW Button Battery Cell Assembly Line

►Suitable for fully automatic assembly and welding manufacturing of steel shell button batteries;

►Modular design, compatible with 8-16mm cell assembly and manufacturing, and realize the traceability of production line data;

►Coaxial laser positioning welding, the equipment welding excellent rate reaches 99.5%;

UW Button Battery Pack Automatic Assembly Line

►From the uploading of cell screening data, to the full set of processes such as lamination accuracy control and welding energy detection during the welding process, fully automatic assembly welding is realized to ensure efficient product output;

►Equipped with high-precision laser bonding welding technology, real-time monitoring technology during welding, and visual size sorting technology to ensure high-quality welding while taking into account high-precision size control, with higher reliability and stability, and the welding excellence rate is 99.5 %;

►It has the function of data traceability to ensure the accurate tracking and binding of the product production process, and the relevant data can be retrieved for viewing later.