Turnkey Cylindrical Battery Module Assembly Line

Cylindrical Battery Module Assembly Line – High‑Efficiency Turnkey Cylindrical Battery Production Line for 18650/21700 Cells

What Is a Cylindrical Battery Module Assembly Line?

A cylindrical battery module assembly line is designed to assemble 18650 and 21700 cylindrical cells into battery modules for EV and ESS applications. Our semi‑automatic line balances automation with manual flexibility, featuring an automatic cell sorter, bracket loading stations, CCD vision inspection, dual‑side spot welding, and a conveyor‑based backend assembly section. It is built around the M179D6 module (78 cells per module) and supports quick changeover between cell types.

Side view rendering of the belt conveyor line

Key Process Description of the Entire Line

The entire line is divided into the following 6 sections:

1. Automatic cell sorter (including automatic picking, kraft paper cutting & pasting, primary barcode scanning, sorting, counting into boxes)

2. Manual bracket loading, module code printing & pasting, nickel strip loading

3. CCD vision inspection

4. Double‑side spot welding

5. Post‑weld CCD appearance inspection (manual fixture removal, fixture return)

6. Backend assembly line

1. Automatic Cell Sorter

Automatic Cell Sorter Process Flow Description:

1. Manually place carton cells onto the belt conveyor or bulk cells into the hopper. (Separate for 18650 and 21700; operators must open carton lids and remove any obstructions in advance.)

2. The module automatically picks cells from the carton and flips them from vertical to horizontal onto the line. (Loading channel is shared; picking is separate for 18650 and 21700.)

3. Apply kraft paper onto the positive terminal of the cell. (Separate for 18650 and 21700.)

4. Barcode scanning of the cell. (18650 and 21700 share the same scanner.)

5. OCV test of the cell. (18650 and 21700 share the same tester.)

6. Sort the cell into 6+1 channels: NG cells are moved to the NG discharge channel; OK cells enter the channel slots. (18650 and 21700 share the same channels.)

7. Transfer and count OK cells to the buffer conveyor; operators manually take cells from the belt into fixtures.

8. Generate a module code; manually print and apply the module code.

Automatic Sorter Parameters

2.Process Flow Description:

1. The 18/21 independent mechanical gripper picks cells (with counting) from the sorting channels and places them into storage boxes.

2. The storage boxes are automatically transferred to the buffer conveyors on both sides; operators manually remove the storage boxes.

3. Operators manually take cells from the storage boxes, load them into brackets and fixtures, then print and apply the module code (one module code can be generated per storage box).

4. The bracket or fixture is moved to the manual nickel strip loading position; operators manually place the fixture onto the CCD polarity inspection infeed channel.

5. Operators manually place empty storage boxes onto the middle buffer conveyor; the storage boxes are automatically transferred to the cell loading position.

3. CCD Vision Inspection

Process Flow Description:

1. Manually place the module with the upper fixture onto the belt conveyor.

2. The module is automatically transported to the CCD inspection station, where vision inspects the positive and negative terminals (poles) of the cells.

3. The module flows out. Good modules proceed to the next process; NG (No Good) triggers an alarm.

CCD image processing effect

>Lighting effect diagram

> Visual Processing Diagram

Configuration and Standards

4. Double-Side Spot Welding Machine

Process Flow Description:

1. Manually place the module fixture onto the conveyor belt; the conveyor belt automatically feeds it into the double-side spot welding machine.

2. Automatic welding.

3. The fixture automatically exits and is merged and conveyed to the manual fixture removal station.

4. Manually remove the fixture, place the fixtures onto the return conveyor belt, and the removed module is automatically conveyed to the next process. NG (No Good) triggers an alarm.

Partial Structural Description of the Automatic Spot Welding Machine:

Automatic spot welding machine configuration and related parameters:

4. Functional Features of the Automatic Spot Welding Machine

1. The left/right X‑axis, Y‑axis, and Z‑axis are independently controlled by motors. Fixture transmission uses a three‑section speed‑adjustable motor; fixture pressing down is also motor‑driven.

2. The equipment uses a PLC with a touchscreen, which displays welding parameters and abnormal weld spot identification in real time. An optional industrial PC can collect welding results via RS‑485 communication, and an interface program can be provided to enable MES communication according to customer requirements.

3. The welding head can be used with either round pins or pointed pins (only one type can be selected per battery pack). The welding head is rotatable, allowing multi‑angle welding.

4. The welding head is controlled by a servo motor, eliminating pressure fluctuations caused by unstable air supply. It also provides automatic compensation of the welding pins within a certain range.

5. The equipment is equipped with a control handle, facilitating machine adjustment, program writing, and teaching.

6. The equipment can be fitted with a barcode scanner; the QR code information on the battery pack can be used as the file name for all welding results (current, voltage, power, time, error codes, etc.) for easy traceability.

7. The equipment includes a fixture detection function to prevent incorrect placement of the fixture (upside down or reversed) or double welding of a battery pack (starting welding again without unloading a completed pack).

8. The equipment has direct air blowing to continuously cool the welding pins, preventing overheating that could affect weld quality, making welding more efficient and stable.

9. Automation programs are saved as Excel files, and coordinate parameters can be modified within the Excel file. As long as the hard drive has sufficient capacity, there is no limit to the number of processing programs. Programs can also be shared between multiple machines via USB drive.

10. The programming for positioning and welding parameter calling is simple, with an easy‑to‑operate interface. It features self‑learning for positioning, supports dual‑array calculation, and automatically calculates shapes including squares, rectangles, staggered arrays, and parallelograms. Setup is simple and convenient – just set the coordinates of a few points, and the coordinates of all weld spots are automatically generated.

11. It supports importing weld coordinates from CAD drawings (more convenient for automatic calculation of regular battery packs). When changing to a different product, only one working origin needs to be set.

12. The equipment supports programming of multiple motion trajectories, allowing welding either horizontally first then vertically, or vertically first then horizontally.

13. The equipment supports local operation functions, including batch operations such as coordinate correction, coordinate overlay, coordinate setting, energy setting, and coordinate copy/delete.

14. Welding at certain points in an array can be quickly canceled without deleting the point coordinates – simply set the left/right energy of that point to zero. This makes it easy to add welding at that point later.

15. The equipment can set multiple weld spots per location and supports different numbers of welds on each side (e.g., two welds on the positive electrode and three on the negative electrode).

16. The equipment supports up to 8 groups of energy switching on one side, accommodating multiple welding parameters within the same battery pack (e.g., different welding energies for positive and negative, or various connector thicknesses/materials). Parameters are automatically called during welding to achieve perfect weld strength and appearance.

17. It has functions for start‑position welding and breakpoint resumption. If the welding process stops due to an abnormal issue, you can choose to return to the origin or continue welding from the breakpoint.

18. The equipment uses three levels of access rights (operator, maintenance, engineer) to prevent unauthorized modification of system parameters.

19. The welding power supply can be set to constant current, constant voltage, or constant power welding modes, improving weld quality. Current monitoring enables bad‑part alarms and no‑current alarms, among others.

20. The equipment includes a welding pin wear alarm. When the pin usage count reaches the set value, the equipment alarms and stops, waiting for manual pin dressing. After dressing, manual confirmation is required before welding can resume, further improving welding stability.

21. The software includes built‑in operation manuals, maintenance manuals, and troubleshooting guides.

5.CCD post-weld inspection

Process Flow Description:

1. Manually remove the fixture, take out the battery module, and place it at the designated inspection position.

2. Press the start button; the CCD takes an image for inspection.

3. Manually flip the battery 180°, then start the inspection.

Configuration and Standards

6 Backend Assembly Line

1. The assembly belt line consists of a middle belt conveyor (40 cm wide) and two side workbenches (30 cm wide).

2. The assembly belt line is equipped with ESOP displays, with 8 workstations on each side, totaling 16 ESOP units.

3. CCD solder joint inspection allows small adjustments of the inspection position and supports fixed-position inspection. The specific inspection method will be determined based on actual results.

4. The testing + marking platform has independent power and an independent ESOP.

Configuration and Standards

urnkey Cylindrical Battery Production Line – Process Overview

Our turnkey cylindrical battery production line follows a structured workflow:

1. Automatic Cell Sorting 

• Manual loading of bulk cells or cartons.

• Automatic kraft paper pasting on positive terminal.

• Barcode scanning and OCV testing

• 6+1 channel sorting (6 OK bins + 1 NG bin).

• Counted cell transfer to buffer conveyor.

2. Manual Bracket Loading & Module Code Printing 

• Independent mechanical gripper picks cells into storage boxes.

• Operators load cells into brackets, print and apply module code (one code per box).

• Manual loading of nickel strips and fixture placement for CCD inspection.

3. CCD Polarity Inspection 

• Fixture automatically moves to CCD inspection station.

• Inspects cell reverse, missing, or misaligned placement.

• Detection range 600×500mm, processing time ≤2s, NG alarm.

4. Double‑Side Spot Welding

• Automatic feeding into double‑side spot welder (model ST‑DW‑600500).

• Styler PDC5000B transistor welding power supply, 220V/50Hz, 3KW.

• Welding efficiency: 3000 cells/hour (0.1mm nickel steel); 3600 cells/hour for 0.2mm slotted nickel steel.

• Welding pressure: 1.5‑3.0kg for pointed pins, 3.0‑5.0kg for convex‑point welding.

• Servo‑controlled welding heads with air cooling and automatic wear alert.

5. Post‑Weld CCD Inspection

• Manual fixture removal, battery module placed under CCD camera.

• 180° flip inspection, detection range 600×500mm, ≤2s per side.

6. Backend Assembly Line 

• 12m conveyor belt with 16 ESOP workstations (21” wireless).

• CCD solder joint inspection (movable).

• Protection board testing + marking station (customer‑supplied tester).

All key production data (OCV, module code, CCD results, welding parameters) are uploaded to the database and linked to a final barcode on each module for full traceability.

Performance Metrics & Quality Assurance

• First‑pass yield (FPY) ≥98% – calculated as (passing modules on first inspection ÷ total modules) ×100%.

• Final yield ≥99.5% – includes rework.

• Equipment uptime ≥98% – excludes material and manual operation delays.

• Welding quality – 0.15mm nickel‑plated steel to 18650 cell: pull force >3kgf, false weld rate ≤0.3%.

• Electrode life – Tungsten‑copper welding pins: 10,000‑20,000 welds per pin with regular maintenance.

📥 Download the Detailed Technical Brochure to explore full specifications and integration guides.

📞 Contact Our Engineering Team for a provide confidential consulting and customized performance analysis for your specific yield goals.