Prismatic Cell Blue Film Wrapping: Solving the Bubble & Wrinkle Challenge
Release time:
2026-01-26
In the assembly of prismatic battery modules, electrical insulation is non-negotiable. While Blue Film Wrapping has become the industry standard for insulating large prismatic cells (replacing UV coating and PET film), manufacturers often face a critical yield killer: Air Bubbles and Wrinkles.
In the assembly of prismatic battery modules, electrical insulation is non-negotiable. While Blue Film Wrapping has become the industry standard for insulating large prismatic cells (replacing UV coating and PET film), manufacturers often face a critical yield killer: Air Bubbles and Wrinkles.
For Tier-1 EV battery manufacturers, a bubble is not just a cosmetic defect—it is a potential point of dielectric breakdown during Hi-Pot testing.
This guide explores the root causes of these defects and how Huiyao Laser's Multi-Axis Servo Tension System solves them, ensuring a 99.8% yield rate.
Why Do Bubbles and Wrinkles Occur?
The wrapping process involves applying a thin layer of adhesive blue film (usually PET or PI based) onto the aluminum housing of the cell. Common failure modes include:
Uneven Tension: If the film tension fluctuates during the high-speed wrapping process (12-15 PPM), the film will either stretch (causing white stress marks) or slacken (causing wrinkles).
Trapped Air: When the film is applied too quickly without proper roller pressure sequencing, air gets trapped between the film and the cell can, forming bubbles.
Static Electricity: A high static charge can cause the film to pre-adhere to the cell before the rollers engage, leading to misalignment.
The Huiyao Solution: Multi-Axis Servo Tension Control
Unlike traditional "passive tension" systems that rely on mechanical springs, Huiyao’s Blue Film Wrapping Machine utilizes a fully digital Active Servo Tension System.
Real-time Adjustment: Servo motors monitor the film tension 1,000 times per second. If the roll diameter changes or speed fluctuates, the motor adjusts torque instantly to maintain constant tension (±0.5N).
Precision Roller Mechanism: Our proprietary roller design applies pressure progressively from the center outward, effectively "squeezing" air out to the edges, ensuring a zero-bubble finish.
Vision Correction: Before wrapping, a CCD camera detects the cell's position. If the cell is slightly skewed, the robot arm compensates automatically, ensuring the film edge alignment is within ±0.1mm.
Blue Film vs. UV Coating: Why Film Wins?
We are often asked: "Why not use UV spray coating?"While UV coating is faster, Blue Film offers superior mechanical protection.
Puncture Resistance: The physical film layer provides a robust barrier against vibration and friction inside the module.
Uniformity: Film thickness is manufactured to be exact (e.g., 0.15mm), whereas spray coating thickness can vary due to nozzle clogging or viscosity changes.
Conclusion
Achieving a bubble-free wrap is the first step toward a safe battery module. Don't let insulation defects compromise your pack's safety.
Struggling with insulation yield rates?
Upload your Prismatic Cell drawing today. Our engineers will provide a free feasibility simulation and a layout proposal for a Bubble-Free Wrapping 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.
© 2026 Huiyao Laser Technology Co., Ltd. All Rights Reserved.
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