Batteries may have been around much, much earlier than we remember, even dating back to the Parthian kingdom in the Middle East more than 2,000 years ago. At that time, people used an earthenware jar filled with vinegar, in which an iron rod wrapped in copper was fixed to produce a few volts, making this the earliest recorded invention of the battery. Nowadays, there are various types of batteries, including lithium batteries, storage batteries, 5 or 7 batteries, etc. Today, Zichen Laser is going to introduce a new type of button battery laser welding applications.
In recent years, the most popular consumer electronics products TWS (true wireless bluetooth) headphones, smart watches, smart speakers, etc., as a representative, the button battery is generally composed of the main control chip, battery, flexible circuit boards, and controllers, etc., of which the cost of the battery accounted for about 10% to 20%. Airpods Pro, for example, its whole contains a total of three batteries: two headphones and charging compartment in each one, the battery in its headphones for the new rechargeable button battery. Compared to other electronic products, the button battery in TWS headphones has a higher value because it is a new type of rechargeable, and its processing technology is more difficult than that of traditional disposable button batteries.
The traditional button battery processing technology is to use the thermal effect of resistance to fuse the solder pads with the battery case to form a resistance welding. This welding technology is convenient, low cost, but the shortcomings are obvious, such as can only be used for a single material welding, weld marks are not beautiful, weld size is not accurate and easy to oxidize black, Phi Feng, and other issues, and in the process of operation by the equipment and personnel operation of the influence of factors is greater, easy to weld tabs fall off, weld foot battery voltage drop and other security issues. Therefore, resistance welding is no longer applicable to the processing of new button cell with high quality requirements.
New button cell in the process is generally applied to the circuit board, the need to weld pins on its surface. For the needs of different circuit boards, the form of welding pins are often a variety of forms, at the same time, the new button cell welding pins are more complex, resistance welding process is not strong, for the existing resistance welding technology can not meet the high quality of the new button cell welding requirements, a number of button cell producers will look to laser welding technology.
Laser welding technology can meet the button battery processing technology diversity, such as heterogeneous materials (stainless steel, aluminum alloy, nickel, etc.) welding, irregular welding trajectory, excellent welding appearance, solid weld, more detailed welding points and more accurate positioning of the welding area. Not only that, laser welding can also make the product consistency is high and reduce the damage to the battery, to avoid the waste of raw materials. Since its establishment in 2014, Zichen Laser has made remarkable achievements in the field of non-metallic material welding, and as the first manufacturer of laser soldering equipment in China, it has made remarkable achievements in the research and development of laser welding process for button batteries.
The advantages of the new button battery's laser welding process are as follows:
- Higher energy density, easier to reach the material absorption threshold (especially high anti-material, the advantage is more obvious);
- A variety of welding trajectory graphics can be realized. Such as sinusoidal line shape, spiral line shape, spiral point shape and so on;
- Smaller weld spot, larger weld depth-to-width ratio, larger contact area for the same weld spot size, and greater weld strength and tensile strength;
- Higher power density. Its welding principle is different from the traditional welding principle based on the large molten pool, more similar to the inlay welding effect, can obtain higher weld strength, especially in the heterogeneous materials welding more advantageous, can reduce the generation of brittle compounds.
