Battery Cover Adhesive Groove Grid for Bubble-Free 3D Film Lamination

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Solution Overview

Problem

Non-metallic battery covers in electronic devices, particularly 3D battery covers, are prone to wrinkles and bubbles when an anti-shattering film is attached, leading to IPX8 waterproof failure and increased maintenance costs due to film separation during removal.

Innovation Solution

An anti-shattering film with a back adhesive featuring an exhaust groove grid and optionally arc-shaped grooves is used, allowing air discharge during high-pressure debubbling to reduce wrinkles and bubbles, ensuring secure attachment and preventing film separation during maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If an anti-shattering film is attached to a 3D battery cover using conventional methods, then the battery cover gains shatter resistance, but wrinkles and bubbles occur due to surface shape changes

Engineering Contradiction:
Improveshatter resistanceVSAvoidsurface flatness
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The back adhesive is divided into multiple regions by exhaust groove grids, creating segmented adhesive zones that can independently conform to the 3D surface while allowing trapped air to escape through the groove channels, preventing bubble formation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The exhaust groove grid creates local variations in adhesive thickness and structure, with grooves positioned at specific locations to facilitate air discharge while maintaining adhesive bonding in other areas, adapting the adhesive properties to local surface geometry requirements

Inventive Principle:
Principle #3Local quality

2Strength

If an anti-shattering film is attached to a 3D battery cover, then shatter resistance is improved, but the risk of IPX8 waterproof failure increases due to bubbles and wrinkles

Engineering Contradiction:
Improveshatter resistanceVSAvoidwaterproof performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The exhaust groove grid segments the adhesive layer into multiple zones, allowing controlled air discharge paths that prevent bubble accumulation and maintain a flat, bubble-free surface essential for IPX8 waterproof certification

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The exhaust groove grid converts the harmful trapped air into a beneficial controlled discharge mechanism, where air is intentionally channeled through grooves during the lamination process, eliminating bubbles that would otherwise compromise waterproof performance

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Strength

If a conventional anti-shattering film is used on a battery cover, then shatter protection is provided, but the film is easy to separate during maintenance

Engineering Contradiction:
Improveshatter protectionVSAvoidfilm attachment stability
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The exhaust groove grid creates local variations in adhesive distribution and bonding characteristics, with grooves positioned to allow controlled air escape while maintaining strong adhesive coverage in bonding zones, resulting in enhanced overall attachment stability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The exhaust groove grid is pre-formed in the back adhesive before lamination, establishing predetermined air discharge pathways that ensure complete adhesive contact with the battery cover surface during the bonding process, creating a robust permanent attachment that resists separation during maintenance

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively reduces wrinkles and bubbles, maintaining IPX8 waterproof integrity and minimizing maintenance costs by ensuring the film remains securely attached to the battery cover.

Implementation Method 1

When a high pressure such as a 13 kg force and debubbling by heating such as at 50°C are applied, air can be discharged through the exhaust groove grid on the back adhesive

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

debubbling by heating such as at 50°C are applied

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP4277249B1Electronic device
Publication Date: 2025.11.05 HONOR DEVICE CO LTD
  • EP4277249B1 patent drawingFigure 1~2
  • EP4277249B1 patent drawingFigure 3~4
  • EP4277249B1 patent drawingFigure 5~6

AI summary

Embodiments of this application provide an electronic device, including a battery cover. The battery cover includes a battery cover body. An inner surface of the battery cover body has an anti-shattering film. The anti-shattering film includes a plastic substrate. A back adhesive is provided on the plastic substrate. The back adhesive is adhered to the inner surface of the battery cover body. A surface of the back adhesive that is adhered to the inner surface of the battery cover body is provided with an exhaust groove grid. In this application, the anti-shattering film with the exhaust groove grid on its back adhesive is closely attached on the non-metallic battery cover body. When a high pressure such as a 13 kg force and debubbling by heating such as 50°C are applied, air can be discharged through the exhaust groove grid on the back adhesive, thereby reducing bubbles and wrinkles and lowering the risk of the IPX8 waterproof failure of the mobile phone. When the battery cover of the mobile phone is removed for maintenance, the anti-shattering film fits well and is not easy to fall off, which will not increase the maintenance cost of the mobile phone.