What Additional Factors Should I Consider When Choosing the Lithium Battery Laser Welding Machine?

As a key process in the manufacture of lithium-ion batteries, the selection of laser welding equipment directly affects the safety and consistency of battery products. This type of equipment realizes the fusion of metal materials at the molecular level by means of a high-energy laser beam, which is especially suitable for the connection of battery components that are sensitive to heat input. The working principle can be briefly described as follows: when the high-density laser beam is focused on the surface of the workpiece, the material instantly absorbs the light energy and converts it into heat, forming a localized melting pool under precise control, and forming a metallurgically bonded weld as the beam moves.

Pulse Laser Welding Machine

• Characteristics: Pulse laser welding machines emit laser energy in discrete pulses. Adopting intermittent energy output working mode, it has the characteristics of high instantaneous power and small heat accumulation. A brand 200W pulse welder, for example, its single pulse energy up to 10J, repeat frequency in 1-20kHz adjustable, especially suitable for 0.1mm lug welding.

Continuous Laser Welding Machine

• Characteristics: Continuous laser welding machines provide a continuous output of laser energy. The power range of 1-6kW is characterized by stable and continuous energy output, typically in the form of fiber lasers.They have a relatively high average power, which allows for a continuous and stable heat input during the welding process. This results in a faster welding speed compared to pulse laser welding machines.

• Advantages:
  • High – speed welding: Suitable for large – scale production of lithium – ion batteries, especially in the manufacturing of electric vehicle battery packs. The continuous laser beam can quickly weld long seams, significantly increasing the production efficiency.
  • Deep – penetration welding: Can achieve deeper penetration depths, which is necessary for welding thicker components in battery packs, such as the connection between the battery modules and the busbars.
• Applicable Scenarios:
  • Mass production lines of electric vehicle battery packs. For example, in a large – scale electric vehicle manufacturing plant, continuous laser welding machines can be used to weld the battery modules together to form a complete battery pack at a high production rate.
  • Welding of large – capacity energy storage battery systems, where the high – speed and deep – penetration welding capabilities can meet the requirements of large – scale production and reliable connections.

Phosphoric Acid Iron Lithium Batteries

• Pulse Laser Welding: Phosphoric acid iron lithium batteries have relatively stable electrochemical properties. However, their electrode materials are sensitive to excessive heat. Pulse laser welding is suitable for these batteries because it can precisely control the heat input, reducing the risk of overheating and degradation of the electrode materials. When welding the electrode tabs of phosphoric acid iron lithium batteries, the short – duration high – energy pulses can quickly melt the metal without causing significant thermal damage to the adjacent electrode materials.
• Continuous Laser Welding: In some cases where high – speed production is required and the heat – affected zone can be effectively controlled, continuous laser welding can also be used. For example, when welding the connections between the battery modules in a large – scale energy storage system using phosphoric acid iron lithium batteries, continuous laser welding can improve the production efficiency while ensuring the reliability of the connections. But strict control over the welding parameters, such as the welding speed and laser power, is necessary to prevent overheating.

Ternary Lithium Batteries

• Pulse Laser Welding: Ternary lithium batteries have a higher energy density compared to phosphoric acid iron lithium batteries. Their electrode materials are more complex and sensitive to heat. Pulse laser welding is often preferred for welding the internal components of ternary lithium batteries, especially in high – end applications such as electric vehicle batteries. The precise heat control of pulse laser welding can ensure the integrity of the complex electrode structures and prevent the formation of defects that could affect the battery’s performance and safety.
• Continuous Laser Welding: For large – scale production of ternary lithium – ion battery packs for electric vehicles, continuous laser welding can be a viable option. However, due to the high energy density and the sensitivity of ternary materials to heat, advanced cooling systems and real – time monitoring of the welding process are often required. This helps to maintain the quality of the welds and the performance of the battery cells.

Power

• Pulse Laser Welding Machine: The power of a pulse laser welding machine is mainly determined by the peak power and the pulse repetition rate. For thin – walled components in lithium – ion batteries, a relatively low – peak – power but high – repetition – rate pulse laser can be sufficient. For example, when welding electrode tabs with a thickness of 0.1 – 0.2 mm, a pulse laser with a peak power of 100 – 300 W and a repetition rate of 1 – 10 kHz may be suitable.
• Continuous Laser Welding Machine: The power of a continuous laser welding machine directly affects its welding speed and penetration depth. For welding thick – walled components in battery packs, such as busbars with a thickness of 1 – 3 mm, a continuous laser with a power of 1 – 3 kW may be required. In large – scale production, a higher – power continuous laser can increase the production efficiency, but it also needs to be matched with appropriate cooling and control systems.In general the principle of power adaptation is as follows:

1. Lug welding: pulse power 100-300W (0.1-0.3mm material)
2. Shell sealing: continuous power 1.5-3kW (1-2mm aluminum)
3. Attention should be paid to the design of power redundancy, it is recommended that the actual power used does not exceed 80% of the nominal value of the equipment.

Spot Size

• Pulse Laser Welding Machine: A smaller spot size is beneficial for high – precision welding in lithium – ion batteries. For example, when welding micro – components inside the battery cells, a spot size of 0.05 – 0.2 mm can ensure accurate melting and joining of the small parts. The small spot size allows for precise control of the heat input area, reducing the risk of thermal damage to the surrounding materials.
• Continuous Laser Welding Machine: The spot size of a continuous laser welding machine affects the width of the weld seam and the heat – affected zone. For high – speed welding of large – scale battery packs, a slightly larger spot size may be acceptable as long as the welding quality can be maintained. However, for critical connections that require high – strength and low – heat – affected – zone welding, a smaller spot size should be selected.

Welding Quality

• Pulse Laser Welding Machine: Pulse laser welding is often favored when high – quality and high – precision welding is required. The precise control of the heat input and the small heat – affected zone can ensure the integrity of the welded joints and the performance of the battery components. For example, in the production of aerospace – grade lithium – ion batteries, where the reliability and performance requirements are extremely high, pulse laser welding can meet these strict standards.
• Continuous Laser Welding Machine: To ensure high – quality welding with a continuous laser welding machine, advanced monitoring and control systems are necessary. Real – time monitoring of the welding process, such as the temperature distribution and the quality of the weld seam, can help to detect and correct any potential defects immediately. In addition, proper selection of the welding parameters, such as the laser power, welding speed, and focal position, is crucial for achieving high – quality welds.

Efficiency

• Pulse Laser Welding Machine: Although the welding speed of a pulse laser welding machine is generally lower than that of a continuous laser welding machine, it can be optimized for high – precision applications. By adjusting the pulse repetition rate and the welding path, the overall production efficiency can be improved. For example, in the production of small – scale battery packs, multi – axis motion control systems can be used to move the workpiece quickly between welding points, reducing the idle time of the laser.
• Continuous Laser Welding Machine: Continuous laser welding machines are designed for high – speed production. In large – scale battery manufacturing plants, the high – speed continuous welding can significantly reduce the production cycle. For example, in the production of electric vehicle battery packs, a continuous laser welding machine can weld multiple seams simultaneously, increasing the production capacity by several times compared to traditional welding methods.

Cost

• Pulse Laser Welding Machine: The initial investment cost of a pulse laser welding machine is relatively high due to its complex optical and control systems. However, in the long run, its lower power consumption and the ability to reduce the scrap rate due to high – precision welding can offset some of the costs. For small – scale production or high – value – added applications, the cost – effectiveness of pulse laser welding can be relatively high.
• Continuous Laser Welding Machine: Continuous laser welding machines are suitable for large – scale production. Although the initial investment may be high, the high – speed production and the relatively simple operation can reduce the unit production cost. In addition, the long – term reliability and durability of continuous laser welding machines can also contribute to cost savings in the long – term production process.

In conclusion, when choosing a lithium – battery laser welding machine, one must consider multiple factors, including the type of the welding machine, the requirements of different types of lithium – ion batteries, basic parameters such as power and spot size, as well as welding quality, efficiency, and cost. It is recommended that no less than three equipment sampling comparison, focusing on: weld depth to width ratio (preferably > 1.5), the degree of surface oxidation (color difference ΔE < 2), tensile strength (up to 90% of the base material). At the same time pay attention to the equipment scalability, such as whether to reserve the blue welding module interface to adapt to the future processing needs of composite materials.