The Art of "Final Sealing": Stopping Pouch Cell Swelling
Release time:
2026-01-14
When clients visit our factory, they often ask one question first: "Can you guarantee no leakage?"
When clients visit our factory, they often ask one question first: "Can you guarantee no leakage?"
For Pouch Cells, the Final Sealing (Degassing) process is the most critical step. If the vacuum isn't deep enough, the cell will swell (gas buildup). If the seal isn't tight, electrolyte will leak.
Here is how our Pouch Cell Finishing Line handles it differently from standard machines.
1. The "3-Stage" Vacuum Strategy
Standard machines just "suck and seal" in one go. This often causes electrolytes to boil over, contaminating the sealing edge.
We use a Step-Down Vacuum Process:
Stage 1 (Low Vacuum): Gently removes bulk air (-50kPa) without disturbing the liquid.
Stage 2 (High Vacuum): Ramps up to -95kPa to pull trapped gas bubbles from the electrode layers.
Stage 3 (Sealing): The heat bar seals the pouch while under vacuum, locking in the pressure state.
2. Pierce-and-Seal Technology
The Challenge: Before final sealing, you must pierce the airbag (gas pocket) to let gas out.
Our Solution: Our automated piercing mechanism is integrated inside the vacuum chamber. It ensures zero exposure to ambient air during the transition.
3. The "Vacuum Fingerprint": MES Traceability (New Section)
How do you prove to your customer that a specific cell was sealed correctly 5 years from now? You need data.
Vacuum Curves: Our system records the Pressure vs. Time curvefor every single sealing cycle.
Intelligent Monitoring: If the vacuum drops too fast (indicating a micro-leak in the chamber) or takes too long (blocked needle), the system automatically marks that cell as "NG".
The Result: Every battery gets a digital passport stored in your MES system.
4. Seal Quality Check (QC)
We don't just hope it's sealed. We verify every cell.
Thickness Check: Laser sensors measure the seal thickness (Accuracy ±0.01mm).
Hi-Pot Test: Ensures no insulation damage to the aluminum plastic film.
Visual Check: CCD cameras inspect for wrinkles or electrolyte contamination.
Summary
A perfect seal is the difference between a 10-year battery and a fire hazard.
Upgrade to our Precision Vacuum Sealing Station for zero-defect production.
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.
© 2026 Huiyao Laser Technology Co., Ltd. All Rights Reserved.
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