Battery lines are often described as one line, but the process is a series of environments: dry room for cell handling, clean zone for module assembly, and a controlled area for pack assembly and testing. The conveyor has to move between them without carrying contamination.
Key takeaways
- Separate cell, module and pack zones by cleanliness and humidity.
- Cell grading is a data-intensive process; plan the IT and buffer capacity.
- Busbar welding needs a stable fixture and a fume extraction path.
- Pack testing is a bottleneck; size the test area before the line.
Zone 1: cell receiving and grading
Cells arrive in trays or cartons and are graded by capacity, internal resistance and voltage. The grading station reads the cell ID and writes the result to the database. The cells are then sorted into groups for module assembly.
The conveyor for cells should be ESD-safe and should not generate particles. Belt conveyors with low-dust belting or roller conveyors with sealed bearings are common. The cell trays should be designed to prevent short circuits and to protect the terminals.
Zone 2: module assembly
Module assembly includes cell stacking, busbar welding, sense wire connection and module test. The zone usually requires a clean environment and a controlled temperature. The conveyor should be enclosed or covered to protect the modules from dust.
The stacking fixture must align the cells within a tight tolerance, because the busbar welding depends on it. The fixture should be designed for the module size and should allow quick change for different module formats.
| Zone | Environment | Conveyor type | Key control |
|---|---|---|---|
| Cell grading | Dry room, 1–5% RH | Belt or roller, ESD | Cell ID, short-circuit protection |
| Module assembly | Clean, 20–25 °C | Belt or roller, covered | Alignment, particle control |
| Busbar welding | Local extraction | Indexing table | Fume, weld quality |
| Pack assembly | Clean, controlled | Roller or chain plate | Weight, insulation |
| Pack test | Controlled | Roller or AGV | Test time, safety |
Zone 3: pack assembly
Pack assembly includes module installation, busbar connection, BMS wiring, thermal interface and enclosure sealing. The pack is heavy, often 300–600 kg, so the conveyor must be designed for the load and the lifting equipment.
Use a roller conveyor or a chain plate conveyor with a pallet. The pallet should locate the pack and should be compatible with the lifting equipment. The conveyor should have a smooth transition to the test station to avoid shock loads.
Zone 4: test and dispatch
Pack testing includes insulation resistance, capacity, communication and leak tests. The test time can be long, so the test area needs multiple stations or a buffer. The test station should have a safety barrier and a fire suppression plan.
After test, the pack goes to dispatch or storage. The conveyor should not leave the pack in a queue without a defined time limit; some tests require the pack to be tested within a window after filling or sealing.
Traceability and data
Every cell, module and pack needs an ID and a record. The data volume is large, so the line controller should store locally and forward to MES. The record should include the cell grading result, the welding parameters, the torque results and the test results.
For automotive battery packs, the traceability requirement is often 15 years. Design the storage and backup accordingly.
Frequently asked questions
Does the whole line need a dry room?
Usually only the cell handling and module assembly areas need low humidity. Pack assembly and test can be in a controlled but less dry environment.
What conveyor is best for packs?
A roller conveyor with a pallet, or a chain plate conveyor for heavy packs. The transfer gaps and the pallet location are critical.
How long does pack testing take?
It depends on the test protocol, but it is often 20–60 minutes per pack. Size the test area accordingly.
Send your cell format, module size and pack weight to our engineers through the contact page; we will help lay out the zones and select the conveyors.
