How do laser welding machines enable highly reliable connections between supercapacitors and cylindrical batteries with micron-level precision?
Publish Time: 2025-11-19
n fields such as new energy vehicles, energy storage systems, consumer electronics, and rail transportation, supercapacitors and cylindrical lithium-ion batteries (such as 18650 and 21700) serve as core energy units. The reliability of their internal connections and casing seals directly determines the safety, cycle life, and internal resistance consistency of the entire module. Traditional resistance welding or ultrasonic welding is prone to problems such as spatter, excessive heat-affected zones, or insufficient connection strength, making it difficult to meet the stringent process requirements of high-energy-density devices. Dedicated laser welding machines, with their non-contact processing, precise and controllable heat input, and automated integration capabilities, have become the preferred equipment for achieving high-quality connections in key components such as tabs-end caps, casing-seales, and busbars-cells, constructing the "lifeline" of the electrochemical system in microseconds.
The core advantage of laser welding machines lies first in their extreme control over the thermal process. Employing either a fiber laser (1070nm wavelength) or a green laser (532nm), the output power is adjustable from 50–500W, with pulse widths flexibly switching between millisecond and continuous modes. For highly reflective materials such as aluminum and copper, energy coupling efficiency is effectively improved through optimization of defocusing, scanning trajectory, and pulse waveform. The weld heat-affected zone is controlled within 0.2mm, preventing separator melting or electrolyte decomposition. Weld joints/seams are uniformly formed, free of porosity, cracks, or spatter, with tensile strength exceeding 85% of the base material. For multi-layer tab stacking in supercapacitors, laser technology enables a combined "penetration welding + cladding welding" process, ensuring low contact resistance (<0.5mΩ) and high mechanical strength.
The structural design is deeply adapted to battery manufacturing scenarios. The equipment integrates a high-precision CCD vision positioning system, which can automatically identify cell QR codes, tab positions, or sealing grooves with a positioning accuracy of ±0.02mm. Equipped with a multi-station rotary platform or linear module, it supports fully automated flow of loading, welding, inspection, and unloading. With an IP54 protection rating, it features built-in fume extraction and inert gas protection (Ar/N₂) to prevent welding oxidation and dust explosion risks. Some high-end models further incorporate online quality monitoring—analyzing the molten pool status in real time through plasma spectroscopy or infrared thermal imaging to automatically reject defective products with poor welds or misaligned welds.
The flexible process meets diverse product requirements. The same equipment can be compatible with various cylindrical battery specifications from 14500 to 4680, as well as button and square supercapacitors, by changing fixtures and calling programs. It supports various trajectories such as spot welding, wire welding, circumferential welding, and spiral welding; welding speeds can reach 200mm/s, and sealing welding of a single cell end cap takes only 3–5 seconds, matching the cycle time of high-speed production lines. The software interface provides parameter database management, supports SPC statistics and MES system integration, and enables process traceability.
Safety and compliance are ensured throughout the entire lifecycle. The equipment complies with CE, UL, and GB/T 18871 radiation safety standards. The laser chamber door is equipped with dual-loop interlocks, eliminating operator exposure risk. Multiple safety mechanisms, including emergency stop, light curtain, and anti-misassembly, guarantee human-machine collaborative safety. All welding parameters are encrypted and stored to prevent unauthorized modification, meeting IATF 16949 automotive industry process control requirements.
Ultimately, the value of a laser welding machine lies not only in "fusion of metal," but also in its ability to stitch together the intricate circuits of the electrochemical world at the micrometer scale, using a laser beam as a needle and energy as a thread. When an electric vehicle stably outputs power at high speed, or when an energy storage system maintains its performance after tens of thousands of charge-discharge cycles, these invisible weld points silently bear the torrent of current. As energy devices move towards high safety, long lifespan, and intelligent manufacturing, high-performance laser welding machines, with their comprehensive advantages of precision, cleanliness, and intelligence, continue to solidify the technological foundation of electrochemical connections.
