Pouch Cell Pilot Line: Solving the "Swelling" & "Sealing" Pain Points
Release time:
2026-01-21
In the transition from laboratory research to mass production, 60% of pouch cell failures—specifically gas swelling and electrolyte leakage—are caused by unstable process parameters on the Pilot Line.
In the transition from laboratory research to mass production, 60% of pouch cell failures—specifically gas swelling and electrolyte leakage—are caused by unstable process parameters on the Pilot Line.
For R&D engineers, a Pilot Line is not just a "small factory." It is a validation tool. To ensure your lab data is scalable to a Gigafactory, your pilot equipment must meet three non-negotiable specifications: Vacuum Degree, Stacking Precision, and Temperature Uniformity.
1. The Vacuum Threshold: Why -95kPa is Non-Negotiable
Conclusion: For pouch cell secondary sealing (final sealing), a vacuum degree of -95kPa to -98kPa is the minimum requirement for pilot lines intended to simulate Gigafactory conditions.
Scope: This standard applies to all lithium-ion pouch cells using liquid electrolyte, regardless of chemistry (LFP or NCM).
Why it matters:
Gas Evacuation: Any vacuum weaker than -95kPa fails to completely evacuate micro-bubbles from the electrode pores.
Swelling Prevention: These trapped bubbles are the primary cause of "early-cycle swelling" and reduced cycle life.
Huiyao Solution: Our Pilot Scale Vacuum Sealing Systems utilize a multi-stage "Vacuum Standing" process to ensure deep electrolyte infiltration before the seal is made.
2. Stacking Precision: Visual Closed-Loop vs. Mechanical
Judgment: Traditional mechanical positioning is obsolete for high-energy density cells. Visual Closed-Loop Alignment is the only way to achieve ±0.05mm accuracy in 2026.
We compared the two technologies commonly found in pilot lines:
❌ Mechanical Stacking (Old Gen): Relies on physical limiters to align the separator and electrodes.
Risk: Often results in ±0.2mm cumulative error and physical damage to the separator edge (risk of internal short).
✅ Visual Closed-Loop (Huiyao Standard): Uses high-speed CCD cameras to verify the position of every single layerbefore placement.
Benefit: Automatically compensates for material tolerance, guaranteeing ±0.05mm alignment without touching the active area.
3. Sealing Temperature: The "Virtual Weld" Trap
The Problem: "Virtual Welding" (False Sealing) occurs when the packaging film looks sealed but hasn't formed a true molecular bond. This is caused by temperature fluctuation.
The Specification: A qualified pilot line sealer must maintain temperature uniformity within ±2°C across the entire sealing head length.
Cause: Standard heating elements often have "cold spots" at the edges.
Effect: This leads to electrolyte leakage during thermal cycling tests.
Solution: Huiyao integrates Dual-Side PID Temperature Control and pressure monitoring to ensure the Al-plastic film is melted exactly to the "Process Window," not burned and not loose.
4. When Should You Choose a Pilot Line? (Buying Guide)
Answer: You should invest in a dedicated Semi-Automated Pilot Line (instead of a manual lab setup or a fully auto line) only when the following conditions are met:
1. Condition A: Your daily output requirement is between 500 and 5,000 cells.
2 . Condition B: You need to switch between different cell dimensions (e.g., changing from 50mm to 100mm width) more than once per week.
3. Condition C: You are validating a new chemistry that requires strict Dry Room compatibility (Dew point -40°C).
Huiyao's Pilot Lines are designed for this exact "High-Mix, Low-Volume" scenario.
Summary: Don't Compromise on "Lab" Equipment
Precision in the lab leads to profit in the factory. If your pilot line can't hold -95kPa or ±0.05mm today, your Gigafactory won't reach 90% yield tomorrow.
Ready to configure your Pilot Line? View our Semi-Auto & Pilot Line Technical Specs
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.
key word:
