Oriented Polyamide Film for Battery Cases
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Solution Overview
Problem
Existing packaging materials for battery cases face challenges in productivity due to the need for coating slip characteristics imparting components, which evaporate and adhere to equipment, and in achieving sufficient volumetric energy density by increasing the thickness of the outer layer film.
Innovation Solution
A packaging material comprising a heat resistant resin oriented film layer, a thermoplastic resin non-oriented film layer, and an aluminum foil layer, where the heat resistant resin oriented film has a shrinkage percentage of 2 to 20%, allowing for excellent formability without coating slip characteristics and maintaining sufficient volumetric energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fatty acid amide series slip characteristics imparting components are coated on the surface of the outer layer film to enhance slipping, then formability is improved, but productivity decreases due to additional coating steps and equipment cleaning requirements
Solution Approach 1:
The invention extracts and eliminates the unnecessary coating step by discovering that the base film material itself possesses inherent slip characteristics through its molecular structure and surface properties. The oriented polyamide film's crystal structure and surface energy provide sufficient slip during forming without requiring additional fatty acid amide coatings, thereby removing the productivity-damaging coating and cleaning steps while maintaining formability.
Solution Approach 2:
The oriented polyamide film layer serves itself by providing the necessary slip characteristics through its own material properties rather than requiring external coatings. The film's molecular orientation and surface characteristics naturally facilitate slipping during the forming process, making the system self-sufficient and eliminating dependency on additional processing steps.
2Manufacturing precision
If the thickness of the outer layer film is increased to improve formability, then formability is improved, but volumetric energy density deteriorates
Solution Approach 1:
The invention changes the parameters of the outer layer film by optimizing its thickness to 3-10 μm and controlling the shrinkage percentage within 5-20% through biaxial orientation processing. These parameter adjustments enable the film to achieve excellent formability and deep drawing characteristics without increasing thickness, thereby maintaining high volumetric energy density of the battery.
Solution Approach 2:
The invention introduces dynamic shrinkage characteristics to the outer layer film by applying biaxial orientation and controlling the shrinkage percentage. This dynamic property allows the film to actively adapt and conform during the forming process, providing excellent formability and deep drawing capability without requiring increased thickness, thus preserving battery energy density.
3Ease of operation
If slip characteristics imparting components are coated on the outer layer film, then slipping performance is improved, but equipment contamination increases requiring cleaning operations
Solution Approach 1:
The invention converts the potential harm of using slip agents into a benefit by utilizing the natural surface properties of the oriented polyamide film. Instead of applying external slip agents that contaminate equipment, the film's inherent low surface energy and molecular structure provide the necessary slipping performance, transforming the problem of equipment contamination into a benefit of clean, maintenance-free operation.
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
This configuration enhances productivity by eliminating the need for slip characteristics coating and maintains high volumetric energy density, enabling sharp and deep configuration forming while preventing pinhole generation and reducing costs.
Implementation Method 1
a shrinkage percentage of a heat resistant resin oriented film layer constituting an outer layer of a packaging material affects formability of a packaging material
Data Source
AI summary
A packaging material for battery cases according to the present invention including a heat resistant resin oriented film layer 2 constituting an outer layer, a thermoplastic resin non-oriented film layer 3 constituting an inner layer, and an aluminum foil layer 4 disposed between both the film layers is characterized in that as the heat resistant resin oriented film, a heat resistant resin oriented film having a shrinkage percentage of 2 to 20% is used. With this packaging material, excellent formability can be secured without coating slip characteristics imparting components and sufficient volumetric energy density can be obtained.