As a highly precise welding process, laser welding is widely used in lithium batteries, particularly in battery cell assembly, where laser welding battery cells technology plays a crucial role in laser welding batterys cell assembly.
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This article will first explore the basic principles of laser welding. Next, we will introduce the advantages of laser welding in lithium battery production. Then, we will delve into the specific application areas of laser welding in lithium battery manufacturing. Finally, we will focus on how to use laser welding to assemble battery cells, which we call laser welding battery cells.
This article uses vivid examples and practical experiences from HANTENCNC to showcase the innovative applications of laser welding in lithium battery production. Before we know how is laser welding battery cells in lithium battery production, lets' learn about the working principle of laser welding battery cells.
1. Working Principle of Laser Welding Battery Cells
Laser welding is a highly precise welding technique that utilizes a laser beam to heat the material to a molten or semi-molten state. By controlling the position and intensity of the laser beam, the materials can precisely join together. Laser welding is typically used in welding tasks that require high precision and complex structures, such as in the field of lithium batteries.
During the laser welding process, the laser beam is focused on a small area of the workpiece surface, raising the temperature to the point where the material melts or reaches a semi-molten state. Moving the laser beam can fuse the welding materials together. Laser welding concentrates energy highly, enabling high-temperature, high-speed, and deep welding while minimizing the heat impact on the surrounding materials.
Laser welding is widely used in the manufacturing of lithium battery applications such as laser welding battery cells etc. For instance, in the electrode manufacturing process of lithium batteries, laser welding is used to connect electrode sheets and electrode wires, ensuring the internal conductivity of the battery. During the battery sealing process, laser welding is employed to weld sealing materials, providing the integrity of the battery casing and preventing leakage of the internal liquid electrolyte.
Through its highly precise characteristics, laser welding technology provides an efficient, stable, and reliable welding solution for lithium battery manufacturing, driving the development and application of lithium battery technology.
2. Advantages of Laser Welding in Lithium Battery Production
Laser welding technology in lithium battery production has many advantages, such as high accuracy, welding stability, non-destructiveness to surrounding materials, scalability for mass production, and high controllability. The advantages are as follows:
2.1 Ensuring High Accuracy and Stability of Welding Points
Laser welding provides a highly precise welding process to control the welding position and depth. This precision is crucial for small and densely packed battery components, ensuring the stability and reliability of welding points.
Laser welding enables the rapid fusion of two materials, which can be identical or different, such as welding aluminum and copper. The high precision and efficiency of laser welding technology ensure the stability and reliability of battery cell components, offering an efficient, stable, and reliable welding solution for lithium battery manufacturing. This, in turn, promotes the development and application of lithium battery technology.
2.2 Ensuring Integrity of Welding Locations and Structural Integrity
Laser welding is a non-contact welding method, involving no physical contact during the welding process. The heat generated by laser welding is relatively low, reducing the thermal impact on surrounding materials. This is crucial for sensitive components and materials within lithium battery assemblies, avoiding potential issues related to contamination and damage that might occur in traditional welding methods. This aspect is particularly important for delicate battery materials and components.
2.3 Suitable for Mass Production
Laser welding is a rapid and highly efficient welding method. It is characterized by high efficiency and speed, allowing the welding process to be completed in an extremely short time.
The high efficiency of laser welding is advantageous for the high production demands of mass manufacturing. It enhances production efficiency and reduces production costs significantly.
2.4 High Controllability
Laser welding offers high controllability, as welding parameters can be adjusted according to different materials and requirements during the laser welding process. This flexibility allows meeting the specifications and designs of various battery packs.
In summary, the application of laser welding battery cells or other components provides manufacturers with high-quality, efficient, and reliable welding solutions.
3. Applications of Laser Welding in Lithium Battery Production
In the manufacturing of lithium batteries, laser welding technology is primarily applied in six areas: electrode manufacturing, battery encapsulation, battery module assembly, sealing welding of cylindrical batteries, sealing pin welding, and battery management systems.
Lithium batteries constitute vast and intricate systems, comprising various components and layers. Each part may use laser welding technology. The battery cell, the core component of a lithium battery, consists of positive and negative electrodes, electrolytes, and separators. These components are stacked together, forming an electrochemical reaction unit, which serves as the fundamental operational unit of a lithium battery.
In the realm of lithium battery applications, the crucial production steps of 'electrode manufacturing' and 'battery module assembly' involving the laser welding battery cells. This article focuses on detailing the laser welding battery cells.
So, how is laser welding battery cells in lithium battery production? The following provides an overview of the assembly of battery cells using laser welding in lithium battery manufacturing:
4. Guide to Laser Welding Battery Cells
In the assembly process of lithium battery cells, laser welding plays a vital role and is utilized for four crucial components: sealing the battery case, connecting the top cover and case, welding the explosion-proof valve, and attaching the tab.
Let's explore how laser welding battery cells'
4.1 Sealing the Lithium Battery Case with Laser Welding
The purpose of employing laser welding in sealing the lithium battery casing is to ensure the integrity and tightness of the battery shell, preventing electrolyte leakage.
Sealing the lithium battery casing with laser welding is mainly applied to early small-sized lithium batteries with a wall thickness of approximately 0.3mm. It requires sealing welding on all sides, and stainless steel is the primary material.
When welding such products, it is necessary to use the battery laser welding machine produced by HANTENCNC.
Demonstration Video of HANTENCNC's battery laser welder
HANTENCNC's newly launched gantry-type Galvo laser welder, which is particularly ideal for precise laser welding battery cells and other components.
A battery laser welding machine, typically ranging from to watts, is used for this process. A recommended specification for casing sealing is a -watt laser power with an output frequency of Hz.
Inert gases such as argon and nitrogen are utilized during welding to achieve a complete seal on the casing. After welding, the assembled case undergoes a gas filling and discharge test in a water tank.
Want more information on Lithium Battery Explosion Valve Laser Welding Machine solution? Feel free to contact us.
The welding machine utilizes WSX's industrial dual swing welding head, allowing a weld seam width of up to 5mm with an effective width of 3mm. Combined with a high-resolution CCD camera, real-time monitoring of the welding position and quality is ensured.
HANTENCNC's newly launched gantry-type Galvo laser welder uses WSX's industrial dual-axis welding head, capable of achieving a weld seam width of 5mm with an effective width of 3mm. Coupled with a high-definition CCD, it enables real-time monitoring of welding position and welding quality in laser welding applications for lithium batteries.
4.2 Laser Welding for Sealing Lithium Battery Lid and Casing
Using laser welding to connect lithium batteries' lid and casing is important to ensure the battery structure is strong and the inner components stay stable.
For lithium batteries with aluminum casing, the casing is shaped by pressing, and the lid is precisely made using CNC machines. After filling the casing with battery materials, the lid and casing must be sealed by laser welding.
Welding Spot for the Lid
To seal the lid and casing, it is necessary to use a battery laser welding machine. The lid welding involves welding all four sides to ensure complete sealing. This means the casing might break even under a gas pressure of 4 kg, but the welded part should stay intact, showing the welding was successful.
Typically, we use the HANTEN CNC -watt battery laser welding machine. We can also design special fixtures for production, making it convenient for our customers.
4.3 Laser Welding for Lithium Battery Safety Valve
Laser welding is used for attaching the safety valve to lithium batteries. This ensures that the battery can safely release internal pressure in emergencies, making the battery safer.
Lithium batteries contain a lot of energy and can explode if punctured or squeezed. So, a safety valve is welded onto the battery's top cover. This valve helps release pressure safely, preventing the battery casing from breaking and causing bigger dangers.
The safety valve is usually placed on the battery's top cover. It's made from thinner material and is welded to the casing, as shown in the picture.
For welding these parts, both platform welding and galvanometer laser welding can be used. We suggest using a -watt platform battery laser welding machine with side blowing to control heat and improve the appearance of the weld.
4.4 Laser Welding for Battery Tab Welding in Lithium Battery Production
4.4 Laser Welding for Battery Tab Welding in Lithium Battery Production
Laser welding for battery tab welding in the lithium battery production process ensures stable energy conductivity.
Tab welding is common in soft-pack lithium batteries. The tabs, connected to the battery's positive and negative electrodes, are conductive materials like metal, such as copper, brass, or aluminum. Welding requirements include no overlap of materials and precise control of laser energy.
Laser Welding
VS Traditional Ultrasonic Welding
When welding tabs, we recommend using a laser galvanometer welding machine with a maximum swing speed of mm/s, combined with a - watt laser. This setup can weld aluminum or copper tabs ranging from 1-2.5mm.
Compared to traditional ultrasonic welding, the key advantage of laser galvanometer welding machines is that they require no consumables and produce minimal or no waste gases or smoke, ensuring high processing efficiency.
HANTENCNC offer platform welding machines and galvanometer welding machines with various stroke lengths. if you interest at laser welding battery cells or our battery laser welding machines, feel free to contact us.
Conclusion
Lithium batteries are a large and complex system. We've covered laser welding battery cells. Still, there are many other laser welding applications we haven't discussed, such as sealing welding for cylindrical batteries, welding of sealing pins, and more.
As lithium battery technology advances, I believe there will be even more laser welding applications. Laser welding, an environmentally friendly method, will become more widely accepted.
Application of laser welding in the field of lithium batteries
Lithium-ion batteries are widely used in various electronic devices (such as mobile phones, laptops, PDAs, digital cameras and digital video cameras, etc.) and transportation vehicles (patrol cars, electric bicycles, electric cars, etc.) due to the advantages of high specific energy, long cycle life, small self-discharge, no memory effect and no pollution, and have become a high-tech industry supported by China's energy sector.
Power batteries refer to batteries used in electric vehicles, which are secondary batteries with larger capacity and output power relative to small capacity batteries (e.g. mobile , laptop batteries, etc.) that can be used in electric vehicle drive power and large mobile power applications. Lithium-ion batteries or battery packs are made in a very large number of processes, and several of these processes, such as explosion-proof valve seal welding, lug welding, flexible connection welding, battery case seal welding, module and PACK welding all use laser welding as the best process. The main materials used for welding power batteries are pure copper, aluminium and aluminium alloy, stainless steel, etc.
batter pack
1'Battery explosion-proof valve welding
The explosion-proof valve of the battery is a thin-walled valve body on the sealing plate of the battery, when the internal pressure of the battery exceeds the specified value, the explosion-proof valve body ruptures to prevent the battery from bursting. The safety valve structure is ingenious and this process is extremely demanding on the laser welding process. Prior to continuous laser welding, battery explosion-proof valves were welded using pulsed lasers, which overlapped and covered joints to achieve continuous seal welding, but the welding efficiency was low and the seal was relatively poor. The use of continuous laser welding can achieve high speed and high quality welding, welding stability, welding efficiency and yield can be guaranteed.
2'Battery lug welding
The positive electrode of the battery is made of aluminium (Al) and the negative electrode is made of nickel (Ni) or nickel-plated copper (Ni-Cu). One part of the manufacturing process for power cells is the welding of the lugs to the poles. In the manufacture of secondary cells it is necessary to weld them together with an additional aluminium safety valve. The welding should not only ensure a reliable connection between the pole lug and the pole post, but also require a smooth and beautiful weld.
3'Battery pole strip spot welding
The materials used for the battery pole strip include pure aluminium strip, nickel strip, aluminium-nickel composite strip and a small amount of copper strip. With the emergence of the QCW quasi-continuous laser from IPG, it has been widely used in the welding of battery strips. At the same time, due to its good beam quality and small welding spot, it has unique advantages in dealing with the welding of highly reflective aluminium strips, copper strips and narrow strip battery strips (strip width below 1.5 mm).
4, power battery shell and cover plate sealing welding
Power battery shell materials are aluminum alloy and stainless steel, of which the use of aluminum alloy is the most, generally aluminum alloy, there are also a few pure aluminum. Stainless steel is the best material for laser welding, especially 304 stainless steel, either pulse or continuous laser are able to obtain the appearance and performance of good weld.
The laser welding performance of aluminium and aluminium alloys varies slightly depending on the welding method used. With the exception of pure aluminium and 3-series aluminium alloys, for which both pulsed and continuous welding is not a problem, continuous laser welding is the preferred method to reduce crack sensitivity. At the same time, according to the thickness of the power battery shell to choose the appropriate power of the laser, the general shell thickness of 1mm or less, can be considered to use a single-mode laser within W, the thickness of more than 1mm need to use more than W single-mode or multi-mode lasers.
Small capacity lithium batteries often use a relatively thin aluminum case (thickness of 0.25mm or so), there are also and so on using the steel case. Due to the thickness of the case, the welding of such batteries is generally done with a lower power laser. The use of continuous lasers for welding thin-case lithium batteries can increase efficiency by a factor of 5 to 10, and the appearance and sealing is better. Therefore there is a trend to gradually replace pulsed lasers in this application area.
5, power battery module and pack welding
Series and parallel connection between the power battery is generally completed by connecting the piece with the single battery welding, positive and negative pole materials are different, there are generally copper and aluminum 2 materials, due to the formation of brittle compounds between copper and aluminum after laser welding, can not meet the use of requirements, usually using ultrasonic welding outside, copper and copper, aluminum and aluminum are generally used laser welding. At the same time, as both copper and aluminium transfer heat very quickly and have a very high reflectivity to the laser, the thickness of the connection piece is relatively large, so a higher power laser is required to achieve welding.
Features of laser welded lithium batteries
From the manufacture of lithium battery cells to the formation of battery packs, welding is a very important manufacturing process. The conductivity, strength, gas tightness, metal fatigue and corrosion resistance of lithium batteries are typical criteria for evaluating the quality of battery welding. The choice of welding method and welding process will directly affect the cost, quality, safety and consistency of the battery. Laser welding has become the preferred solution for many welding tasks due to the advantages of safe and reliable welding, process precision and environmental protection.
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