Cylindrical lithium batteries such as 18650, 21700, 26650, 32650, 32140 etc. are widely used in new energy storage, electric bicycles, digital electronics and other products. And because the voltage and capacity of a single cell is limited, multiple cells need to be put together in series and parallel to form a battery module for practical applications.
CHEEBO has developed spot welders for cylindrical lithium batteries, which are dedicated welding devices that make reliable connections between cylindrical battery cells and nickel strips or busbars, and play an integral part in lithium battery module assembly. Compared with traditional soldering, spot welding has a shorter heat-affected zone, enabling stronger solder joints and higher consistency, effectively avoiding safety issues such as overheating, leaking electrolyte, or swelling cells. Spot welders for cylindrical lithium batteries are suitable for small-scale DIY production or medium-sized workshops, as well as fully automated production lines for mass production.
I. Core Working Principle
The mainstream cylindrical lithium battery spot welders as of today mainly adopt the principle of precision resistance pulse welding. The principle is based on Joule heating: When the cell pole approaches the nickel strip, a high current pulse is discharged through the welding electrode onto the contact area. The resultant contact resistance at the metal interface causes a high-temperature spot, melting the surface of the nickel strip and cell pole and causing them to fuse. Once the current stops, the molten metal forms instantly, completing the bond.This process occurs in just milliseconds. The zone affected by heat is extremely small. The heat does not reach very deep into the battery itself, and thus the internal electrolyte, diaphragm, and other core materials is protected from burn-through, resulting in possible thermal damage, degraded performance and other safety issues.
II. Intonation and Classifications:
Cylindrical lithium battery spot welders can be classified into these three main categories based on automation, structural design and intended scenarios of use:
1. Portable Lithium Battery Spot Welder description: Hand-held, light-weight weighing less than a kilogram, it needs no external high power supply thanks to an internal energy storage battery. Applications: DIY use for personal projects, experiments, and small-batch productions of samples to be given out for testing. Capabilities: Can weld 0.1mm pure nickel strips and 0.15mm nickel plated steel strips together, and span a range of 18650 and 21700 cells. Advantages: Compact, cheap and easy to operate. Limitations: Very little welding power, unsuitable for thick strips, and of course cannot be used to weld large packs together in modules.
2. Desktop type Semi-Automatic Lithium Battery Spot Welder description: Foot-operated Widespread in medium and small workshops. A multi pulse or transistor sourced power supply is usually used, and the welder has a stable output. Applications: Used where medium production volumes must be generated, and high quality welding is a requirement. Capabilities: Can be drilled to handle welds for 0.1-0.3mm nickel strips, and can weld all sizes of cylindrical lithium batteries. Usually has pulse regulating features, and a voltage stabilizing feature. Advantages: Stable welding results, evenly spaced solder points, and an alarm for abnormal or cold positions in the tube. Limitations: Requires someone operating the machine to guide the cell being welded into place correctly, and thus is not as fast as an automatically operated machine.
3. Automatic Cylindrical Battery Spot Welder description: High quality industrial equipment employing many axes, relatively high-speed servo positioning. Computers on the machine help user position the machine accurately. Applications: Mass production and assembling of battery packs for electric bicycles, trimmers, power tools, drones, etc. Capabilities: Meet or exceed a ± 0.01mm accuracy, and have a throughput or output on the order of 4000 cells per hour, depending on size of cell. Automatic alarms in case of false welds or if a cell happened to be missing from the guidance. Advantages: High efficiency, the welding is precise, very little variability in results, and not much requires help from a human.
III. Core Advantages of CHEEBO Technology Spot Welders 1. High Safety, No Cell Damage: The explosive high temperature, heated spot with little diffusion allows for the cell to not overheat, bulge, or have electrolyte leaking to the outside during the spot this spot welding. The cells retain their original performance level, and provided no safety issues during the actual welding process.
2. Firm Solder Joints and Strong Stability: Excellent pulling strength and good conductivity of the cell and module. The current being transmitted in a uniform manner, and does not locally heat the cell and cause too much voltage drop.
3. Wide Adaptability and Flexibility: CHEEBO welders can handle all nerds of the mainstream 18650/21700/26650/32650 cells. Upon the same footing they work with both pure nickel strips, nickel-plated steel strips, and meet the series-parallel welding requirements for most different modules of batteries.
4. Balanced Efficiency and Precision: Small models: Excellent for DIY persons/facilities and flexible small batch processing. Simple operation, and requires no special skills to run. Automatic models: Large industrial production use, with visual positioning, intelligent detection, and good consistency and yield.
