SHINHOP laser

The characteristics of power batteries themselves are that they output large currents, have relatively high voltages, and have relatively large capacities. The output power can meet the power supply needs of various electric vehicle drives. The battery modules we commonly see on the market are mostly PACK power batteries composed of lithium battery modules, filled with various battery cells. However, the types of battery cells in the same PACK need to be unified, including the size specifications, capacity, current voltage, and the components that need to be welded, which are numerous, leading to an increase in the manufacturing process. Commonly used component areas for laser welding include: explosion-proof valve sealing welding, tab welding, connection piece welding, safety cap welding, shell sealing welding, module welding, PACK package welding, busbar welding, electrode pole welding, protection board welding, flip plate welding, tab aluminum to nickel transition, etc. The battery materials include copper, aluminum and aluminum alloys, nickel and nickel alloys, stainless steel, etc.
1000W-2000W welding solution:
The material thickness of components such as explosion-proof valves, tabs, safety caps, shell sealing, and electrode poles is generally small, usually between 0.2 to 2mm. These components mainly require sealing or have low strength requirements for the weld seam. The laser power used for welding these components is generally relatively small, and using 1000W, 1500W, or 2000W lasers can basically meet the requirements.
4000W-6000W welding solution:
The weld seam depth of the module side plate and busbar is generally between 2 to 4mm, with higher strength requirements for the weld seam. If a relatively low power laser is used for welding, it will lead to excessively slow welding speeds, and the weld seam's melting depth and strength may not meet the requirements. At this time, we need to choose a higher power laser, such as 4000W or 6000W lasers:
1. Can ensure the melting depth of the weld seam;
2. Can ensure relatively fast welding speed, improving production efficiency;
3. With appropriate welding heads, it can effectively enhance the bridging capability of the weld seam, allowing for a larger assembly gap tolerance;
4. Has a large window for welding process parameters, which can more stably ensure product quality.
Power battery module side plate welding:
In terms of module side plate welding, power battery packs commonly use aluminum alloy profiles and plates as the structural components of the module's outer frame. The quality of the welding determines the rigidity of the overall structure of the module.
Welding requirements:
The weld seam should be uniform, with a melting depth of more than 2mm, and the weld seam strength should be high, with no breakage in the weld area during strength testing.
Basic equipment: 4000W fiber laser, remote scanning welding head.
Welding platform: Robot.
Welding requirements: Welding power 3600W, welding speed 3.6m/min.
Welding effect

Partially enlarged weld seam appearance

Weld seam dissection, performing metallographic inspection of the weld seam cross-section

From the above image, it can be seen that the weld seam width is 2.93mm, the melting depth is 2.38mm, and there are basically no air holes or cracks inside the weld seam. The weld seam formation meets the requirements.
Tensile test

A tensile test was conducted on a weld seam of 70mm in length, with the maximum tensile force of the weld seam being 17.8KN. The joint broke in the heat-affected zone of the base material, indicating good welding results.
From the above example, I can conclude that the advantages of the 4000W fiber multi-mode laser welding are as follows:
1. The output optical system uses a reinforced output fiber, with the output connector being QBH. The beam quality is good, and it can be configured with welding heads from mainstream manufacturers at home and abroad;
2. It has multiple control modes and good high-reflection resistance performance;
3. It has strong advantages for welding materials such as aluminum and copper in the power battery industry and has been widely applied in the power battery industry.
With the continuous development and maturity of laser welding technology, applications suitable for the new energy vehicle power battery field are also continuously expanding.
Finally, the author notes:
Now many power battery module welding manufacturers are starting to use domestic lasers. The main domestic laser manufacturing companies include Ruike Laser and other domestic major manufacturers. In terms of cost performance, they have begun to achieve a lead over imported IPG fiber lasers. The entire power battery welding system relies heavily on the technology and quality of fiber lasers, just like the role of a car engine. If it stops working or encounters any problems, it will paralyze the entire system. Of course, other compatible subsystems are also indispensable. The stronger the compatibility of the entire system, the smoother the system application will be. Therefore, we say that the application of domestic lasers has begun to achieve "overtaking" because their compatibility with other domestic supporting product systems has become stronger.
[This article is compiled and written by "SHINHOP Laser", with some images sourced from the internet for reference and learning purposes only. Please do not reprint/copy. If there is any infringement, please notify for deletion!]