Colored Battery Packaging Laminate That Prevents Delamination
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Solution Overview
Problem
Existing battery packaging materials face issues with partial delamination and non-uniform coloring when using carbon black pigments, especially under severe environments, and require improved moldability, heat resistance, and moisture resistance to accommodate increasing battery capacities.
Innovation Solution
A packaging material comprising a substrate layer made of a heat-resistant resin, a metal foil layer, a sealant layer, and a colored adhesive layer with a specific composition of a two-part curing type polyester urethane resin, which includes a polyester resin and a polyfunctional isocyanate compound, to ensure uniform coloring and enhanced adhesion and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a print layer containing carbon black pigment is provided on the inner surface of the outer resin layer to color the battery packaging material black, then the battery appearance is unified and luxury feeling is achieved, but the print layer partially cracks and peels off during deep drawing or stretch forming, exposing the underlayer and impairing uniformity
Solution Approach 1:
The patent extracts the pigment from the print layer and incorporates it directly into the resin material itself. Instead of having a separate print layer that can crack and peel, the black pigment is mixed into the resin to create an inherently colored material that maintains uniformity and integrity during molding processes.
Solution Approach 2:
The patent creates a composite resin material by combining the base resin with black pigment particles. This composite structure allows the material to maintain both the desired black coloration and the mechanical properties needed for deep drawing and stretch forming without layer delamination.
2Volume of stationary object
If the substrate layer is made thinner to reduce overall packaging material thickness, then the battery capacity can be increased, but the moldability and strength of the packaging material deteriorate
Solution Approach 1:
The patent modifies the physical and chemical parameters of the resin material, specifically controlling the molecular weight and molecular weight distribution. By optimizing these parameters, the resin achieves enhanced mechanical strength and moldability even at reduced thickness, allowing thinner packaging materials to maintain sufficient structural integrity.
3Illumination intensity
If a print layer containing pigment is used for coloring, then the battery can be colored uniformly, but under severe environments such as high-temperature and high-humidity conditions, the print layer delaminates and the non-black underlayer is exposed
Solution Approach 1:
The patent removes the separate print layer structure and integrates the coloring function directly into the resin material. This eliminates the adhesive interface that is prone to delamination under severe environmental conditions, ensuring long-term color uniformity and reliability.
Solution Approach 2:
The patent creates a homogeneous resin material with uniformly distributed pigment particles throughout the matrix. This homogeneous structure ensures consistent coloration and eliminates layered structures that could delaminate, maintaining reliability under high-temperature and high-humidity conditions.
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 provides a packaging material with improved moldability, strength, and resistance to environmental stress, preventing delamination and maintaining uniform coloration even under harsh conditions, while ensuring excellent heat resistance and adhesive properties.
Implementation Method 1
a colored adhesive layer with a specific composition of a two-part curing type polyester urethane resin, which includes a polyester resin and a polyfunctional isocyanate compound
Implementation Method 2
a substrate layer made of a heat-resistant resin... ensuring excellent heat resistance and adhesive properties
Implementation Method 3
a colored adhesive layer provided between the metal foil layer and the substrate layer... enhanced adhesion
Data Source
AI summary
A packaging material includes a substrate layer, a metal foil layer laminated on an inner side of the substrate layer, a sealant layer made of a thermoplastic resin and laminated on an inside of the metal foil layer, and a colored adhesive layer provided between the metal foil layer and the substrate layer. The substrate layer is 2.0 to 5.0% in MD and TD hot water shrinkages, 1.5% or less in a difference between the MD and TD hot water shrinkages, 1.5 to 3 GPa both in MD and TD elastic modulus. The colored adhesive layer is made of a colored adhesive composition containing a color pigment and an adhesive. The colored adhesive layer is composed of a colored adhesive composition of 5 to 10 g/m2 and contains the color pigment of 0.25 to 0.49 g/m2.