Cylindrical Cell Assembly Guide: 300 PPM Speed for 4680/21700
Release time:
2025-12-03
High-Speed Cylindrical Battery Assembly refers to the automated production of battery packs utilizing 21700 or 4680 cells, with throughput requirements exceeding 300 PPM. Key technologies used include Rotary OCV/IR Sorting for rapid grading and Galvo Laser Welding as means to connect thousands of cells without experiencing mechanical stress during traditional wire bonding processes.
High-Speed Cylindrical Battery Assembly refers to the automated production of battery packs utilizing 21700 or 4680 cells, with throughput requirements exceeding 300 PPM. Key technologies used include Rotary OCV/IR Sorting for rapid grading and Galvo Laser Welding as means to connect thousands of cells without experiencing mechanical stress during traditional wire bonding processes.
Tesla's 4680 and 21700 cells have become the standard in high-performance EV manufacturing. But for manufacturing engineers, cylindrical forms present a unique math problem - volume.
A standard electric vehicle (EV) pack could contain as few as 300 prismatic cells but as many as 4,000+ cylindrical cells, so your production line needs to be fast enough and productive enough. For your line to meet its targets and meet production targets successfully, its speed alone won't do; productivity needs to be "gatling gun".
Here is how we designed Cylindrical Module Lines that reach 300+ Parts Per Minute without compromising on quality.
1. The Sorting Bottleneck: OCV/IR at Speed
Before assembly, each and every one of those 4,000 cells must first be graded.
The Challenge: Manual sorting is infeasible while standard pick-and-place sorting methods take too much time to work effectively.
Solution: At our facility, we utilize Rotary High-Speed Test Stations. Rather than stopping-and-going, cells are examined while moving on a rotary dial.
Data: Our system measures OCV (Voltage) and IR (Resistance) quickly in milliseconds, sorting cells into 10+ grades with 99.9% accuracy at speeds exceeding 300 PPM.
2. Connection Tech: Wire Bonding vs. Laser Welding
How do you connect 4,000 cells to a busbar efficiently?
| Feature | Wire Bonding (Ultrasonic) | Laser Welding (Galvo) |
| Speed | Slow (Point-to-Point) | Fast (Scanning) |
| Consumables | High (Aluminum Wire) | Zero (Direct Fusion) |
| Resistance | Higher | Lower (Solid Metal) |
| Durability | Risk of vibration fatigue | High Strength |
3. 4680 Special: The Tabless Challenge
The new large-format 4680 cells feature "tabless" designs which require intricate multi-point welding on their end caps.
Precision: Our vision systems recognize the precise "flower pattern" of current collectors, dynamically adjusting weld paths until 100% connectivity without burning separators is reached.
Scale Your Cylindrical Line
Whether you are packing 18650s for power tools or 4680s for EVs, speed is your currency.
See our high-speed solution: EV Cylindrical Battery Assembly Line
AUTHOR: The Huiyao Laser Engineering Team
A collective of solution architects and process engineers at Huiyao Laser, 100% dedicated to solving the core bottlenecks in EV and ESS battery manufacturing.
© 2025 Huiyao Laser Technology Co., Ltd. All Rights Reserved.
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