The MOPA pulsed fiber laser has adjustable pulse width, wide frequency range, and more adjustable parameters during its processing. Therefore, more materials can be processed, the processing effect is better, the application is more extensive, and the market demand is growing every year. MOPA is a high-end product in pulsed fiber lasers, and the market application has gradually developed to the high-end industry field, which also puts forward higher requirements for laser power and performance parameters.

Part 1 Unique processing advantages guaranteed by leading technology

The newly launched high-power MOPA laser solution adopts the self-developed MOPA 500-2000W pulsed single-mode laser, which is the first high-performance MOPA laser using a single-cavity high-energy mode in China. The maximum average power can reach 1000W, 2000W, and the maximum single pulse energy can reach 100mJ. The MOPA laser has multiple power options and is compact. Due to its overall maintenance-free, it is easy to operate and can be directly integrated into user equipment, making it an ideal laser source for applications such as precision material processing for lithium batteries.

1.1 High beam quality

The excellent beam quality makes it have a smaller divergence Angle compared with similar models, and can adapt to the use of high-speed galvanometer.

1.2 High Energy

Single pulse energy can be customized, the maximum single pulse energy up to 100mJ.

1.3 Peak power

The higher peak power can improve the efficiency of cutting, cleaning and other applications, so that the processing speed is fast, the heat affected zone is small, and the maximum peak power can reach MW class.

1.4 Adjustable pulse width, optional energy distribution

There are square and round options, using different energy distributions and shapes to adapt to different application scenarios.

 

Part 2 Meet the new energy industry a variety of processing applications

2.1 Cutting application

The cutting process of high power MOPA laser in the lithium industry can be applied to pole cutting, pole cutting, battery module disassembly, etc., and the pole ear and the lead piece are welded after cutting. With the development of long cell battery technology, the electrode length of the cell is basically greater than 300mm, which can ensure the cutting effect and the uniformity of the overall length, and the role of high-power MOPA is particularly obvious in this respect.

2.2 Welding application

MOPA 500-2000W pulsed single-mode laser with its excellent beam quality, wide pulse width selection range, high single pulse energy and fear of high reaction and other advantages, suitable for the combination from thin to thick of any two materials overlap welding of copper, aluminum, nickel, steel and other materials, especially in dissimilar material welding, high heat impact requirements, high back mark requirements or penetration risk welding scenarios.

2.3 Cleaning application

In terms of cleaning and surface treatment, MOPA 500-2000W pulsed single-mode laser shows a unique advantage, it can be used for pole cleaning, blue film (paint) cleaning, battery pole/injection hole cleaning and battery aluminum shell cleaning. No matter which process has strict requirements for the application of laser technology, the laser has carried out in-depth research and repeated trials on each material and process, targeted development of each process, and obtained certification:

a. Remove the dirt on the surface of the aluminum shell of the battery cell and the particles generated by the laser treatment process;

b. The surface roughness of the core is consistent, no sharp burrs, easy to tape and attach;

c. The surface appearance of the battery cell is consistent, without local yellowing and blackening;

d. Surface tension ≥50000dyn/cm after treatment, attenuation ≥36000dyn/cm after 30min;

e. After three times of damage depth treatment, the cleaning depth of the aluminum shell substrate is less than 10μm;

f. Roughness Ra≤2, preferably 0.5~1.6;

g. Laser continuous treatment for three times, the temperature rise of aluminum shell substrate during the treatment process is less than 10℃;

h. Laser treatment process without particle secondary pollution.

2.4 Woolen application

The high power MOPA laser is constantly exploring and trying in the process of treating the cell shell coating. In the research process, it is concluded that the high energy and high repetition frequency laser pulse acts on the material surface. The material absorbs light energy, and the light energy is converted into the heat energy of the material, which causes the temperature of the material to rise, and the local melting and gasification. 

The high energy density laser input even ionizes the material, melting the material to create a melt pool. The molten pool is the key to the formation of the woolen point. The heat energy converted by the absorption of light energy by the material is transferred around and inside the molten pool, and temperature gradients are generated horizontally and longitudinally in the molten pool. The directivity of the temperature gradient affects the directivity of the surface tension and determines whether the molten material in the molten pool flows from the periphery to the center or from the center to the periphery. The laser pulse width is in the order of nanoseconds, and the action time on the surface of the material is short. After the pulse action, the deformation molten pool is cooled and solidified quickly to form a woolen point. In the process of laser coating, the adjustable process parameters mainly include pulse frequency, pulse waveform, pulse energy, pulse width, protective gas, spot size, defocusing amount, etc. 

The pulse frequency is large, the wool speed is fast, and the wool efficiency is high. Other parameters regulate the form and size of the energy input, and the following verification results are obtained:

a. Full spot coverage, overlapping rate 30%-60%;

b. Surface tension > 50000dyn/cm;

c. Surface roughness: can reach Rz1-10 range;

d. Reflection Angle 60±40.

The continuous progress of fiber technology, optics and laser control technology has promoted the product innovation and development of MOPA pulsed fiber lasers. Efficient optical fiber amplification technology, intelligent laser control system and the maturity of precision optical devices also provide strong technical support for the research and production of MOPA lasers.