Laser welding has many advantages such as deep melting, fast speed, small deformation, etc., which can greatly improve the safety of power battery. Laser welding on the welding environment requirements are not high, high power density, not affected by the magnetic field, is not limited to conductive materials, does not require vacuum working conditions and welding process does not produce X-rays and other advantages, is widely used in new energy vehicles and power battery manufacturing field. Laser welding technology can greatly improve the processing efficiency of power battery, welding precision, to ensure safety, reliability, consistency, reduce costs and extend service life.
In the production of power batteries, laser welding is used in the cell assembly and battery PACK link.
The core assembly section - section: laser welding process used in the shell, top cover, sealing nails, lugs and other welding links
Core assembly section specifically includes core winding, stacking, lug welding, core into the shell, shell top cover welding, liquid injection, liquid injection port packaging. The electric core is the smallest unit of the power battery, and the quality of the electric core determines the performance of the battery module, which in turn affects the reliability of the entire power battery system.
Compared with the traditional argon arc welding and resistance welding, laser welding has significant advantages:
- Narrow heat-affected zone, welding deformation is small, especially suitable for welding of micro-pieces;
- Through the optical fiber guidance or prismatic deflection, can be long-distance welding;
- Very high energy density;
- Does not need vacuum protection and X-ray protection, and is not affected by magnetic field.
Post-processing section - back section: laser automation system to replace the traditional manual assembly methods used in module PACK
The specific links of post-processing section include chemical composition, testing and classification, and PACK module, and the main equipment includes chemical composition machine, capacity separation and testing device, process storage and logistics automation, and PACK automation equipment. Among them, the laser automation system is commonly used in the module PACK assembly line to weld the connecting pieces in the battery PACK module.
In addition, the laser can also be used for welding explosion-proof valves on the cover plate after the module. The explosion-proof valve is usually two aluminum metal pieces laser welded into a certain shape with grooves designed to rupture and relieve pressure when the battery pressure is too high. Due to the explosion-proof valve and the cover with a small gap, it is difficult to accurately put into position, and thus the laser welding process requirements are extremely strict, requiring weld sealing, strict control of heat input, to ensure that the weld destructive pressure value stabilized within a certain range, otherwise it will have a greater impact on the safety of the battery. Explosion-proof valves usually use splicing welding, composite welding. As the laser welding process continues to go up, laser welding penetration rate is expected to go up.
Laser cutting
Laser cutting technology can be applied to lithium battery manufacturing process in the pole lug cutting and molding, pole slitting and diaphragm slitting and other processes, compared to die-cutting, laser cutting has a higher degree of accuracy, lower operating costs and other advantages, which will help the battery production efficiency and cost reduction. Compared with traditional mechanical cutting, laser cutting has the advantages of no physical wear and tear, flexible cutting shape, edge quality control, higher accuracy and lower operating costs, which is conducive to reducing manufacturing costs, improving production efficiency and significantly shortening the cycle of die-cutting new products.
Polar ear cutting
Laser pole ear molding is currently the mainstream technology, process parameters, control systems, cutting station design determines the speed and quality of cutting. Traditionally, the main use of mechanical die-cutting process. Mechanical die-cutting process has the limitations of fast mold loss, long time to change the mold, poor flexibility and low production efficiency, and has been increasingly unable to meet the development requirements of lithium battery manufacturing. Due to the many advantages of laser cutting technology, with the high-power, high-beam quality nanosecond lasers, single-mode continuous fiber technology maturity, the current laser auricle cutting has gradually become the mainstream of auricle forming technology. Laser lug molding is generally used for roll-to-roll continuous cutting, and its main process flow is as follows: unwinding, tension control, deskew control, laser cutting, secondary de-dusting, winding.
Pole piece cutting
Pole piece cutting disc slitting and die-cutting, laser cutting three ways, disc slitting and die-cutting there is a tool wear problem, which is likely to cause process instability, resulting in poor quality of the pole piece cutting, resulting in a decline in the performance of the battery; laser energy and cutting speed are the two main parameters of the process, the cutting quality of the impact is huge. When the laser power is too low or moving too fast, the pole piece can not be completely cut, and when the power is too high or moving too low, the laser on the material role of the area becomes larger, the size of the slit is larger.
Diaphragm cutting
The laser cutting module cuts the diaphragm wound by the turning roller alternately switching two diaphragm curling components, realizing the function of automated uniform cutting of the diaphragm, avoiding the phenomena of powder removal, picking silk, broken film, and non-stop cutting during the cutting process, which is convenient for the practical use in the batch production line.
Laser Cleaning
Laser cleaning before pole coating can effectively avoid the damage caused by the original wet ethanol cleaning; laser cleaning before battery welding using a pulsed laser to make the substrate heat vibration expansion of pollutants to overcome the surface adsorption force from the substrate to achieve decontamination; battery assembly process laser cleaning can be insulating plate, end plate laser cleaning, cleaning the surface dirt of the battery cell, coarsening the surface of the battery cell, to improve the adhesion of the adhesive or adhesive coating.
Before coating the pole piece
Positive and negative electrode sheet of lithium battery is coated with lithium battery positive and negative materials on the metal thin strip, metal thin strip in the coating of electrode materials, the need for metal thin strip cleaning, metal thin strip is generally aluminum thin or copper thin, the original wet ethanol cleaning, easy to damage other parts of the lithium battery, the laser dry cleaning machine can effectively solve the above problem.
Battery welding before
The use of pulsed laser direct radiation decontamination, so that the surface temperature rises and thermal expansion occurs, thermal expansion of pollutants or substrate vibration, so that the pollutants to overcome the surface adsorption from the substrate surface so as to achieve the purpose of removing surface stains on the object. This way can effectively remove the dirt, dust, etc. on the end surface of the pole pole of the electric core, and prepare for the battery welding in advance, in order to reduce the defective products of welding.
Battery assembly process
In order to prevent lithium battery safety accidents, generally need to lithium battery cell external adhesive treatment, in order to play the role of insulation, to prevent the occurrence of short-circuit, as well as to protect the line, to prevent scratching. Insulation plate, end plate laser cleaning, cleaning the surface of the battery cell dirt, roughening the surface of the battery cell, to improve the adhesion of the adhesive or glue, and cleaning will not produce harmful pollutants, belonging to the green cleaning method.
Laser marking
In order to better control the quality of products and trace the whole production information of lithium batteries, including raw material information, production process and technology, product batch, manufacturer and date, etc., it is necessary to store the key information in the two-dimensional code and mark it on the battery. Laser marking is characterized by strong permanence, high anti-counterfeiting, high precision, high abrasion resistance, safety and reliability, which can provide the best solution for product quality tracking.
Wavelength Optoelectronics is deeply engaged in the field of laser optics, and is a major supplier of precision optical components and assemblies in China, providing laser optical components for many well-known laser equipment manufacturers, and its products include scanning lenses, beam expanding mirrors, collimating mirrors, focusing mirrors, cutting heads, and welding heads, etc., which are used in the field of lasers. The laser welding, cutting, cleaning and marking technologies involved in the manufacture of power batteries, Wavelength Optoelectronics is dedicated to researching and deepening the layout to provide competitive products and services for laser processing and manufacturing enterprises, and to help the global new energy field of high-end equipment, efficient and intelligent.
- New Energy Power Battery Module
- Optical components all quartz design with water cooling
- D30 high power water-cooled galvanometer
- With imaging vision system
- Suitable for 6KW laser power
