Battery Packaging Laminate Resists Curling via Stress-Thickness Control
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Solution Overview
Problem
Existing battery packaging materials face curling issues during molding due to stress concentration, which can lead to positioning and gripping failures, and increasing the thickness of the barrier layer to suppress curling results in increased weight and cost without improving capacitance, while thinning the resin layer compromises sealing and insulation properties.
Innovation Solution
A battery packaging material with a laminate structure comprising a substrate layer, a barrier layer, and a heat fusible resin layer, where the total thickness is between 60 µm to 220 µm, the product of the stress value and thickness of the heat fusible resin layer at 10% stretching is 1,200 Pa·m or more, and a lubricant is applied to the surface to reduce stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the thickness of the barrier layer is increased to suppress curling, then curling suppression is improved, but weight and cost increase
Solution Approach 1:
The invention changes the parameter of heat fusible resin layer thickness to 40 μm or more, which provides sufficient weight and stress resistance to suppress curling during molding without requiring an excessively thick barrier layer, thus balancing curling suppression with weight control
Solution Approach 2:
The invention uses a composite laminate structure combining metal foil barrier layer with heat fusible resin layer, where each layer contributes different properties - the metal foil provides barrier function while the resin layer provides weight and stress resistance to suppress curling
2Stability of the object's composition
If the thickness of the resin layer is increased to suppress curling, then curling suppression is improved, but sealing and insulation properties deteriorate
Solution Approach 1:
The invention optimizes the resin layer thickness to a specific range (40-120 μm) that provides sufficient weight for curling suppression while maintaining adequate sealing and insulation properties, preventing both curling and reliability degradation
3Stability of the object's composition
If the total thickness of the laminate is increased to suppress curling, then curling suppression is improved, but formability deteriorates
Solution Approach 1:
The invention sets the total laminate thickness within 60-220 μm, which provides sufficient weight to suppress curling while remaining thin enough to maintain good formability during the molding process
Solution Approach 2:
The invention applies local quality by concentrating the necessary thickness and weight in the heat fusible resin layer (40 μm or more) rather than uniformly distributing thickness, which suppresses curling at critical areas while maintaining overall formability
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 effectively suppresses curling while maintaining formability and strength, ensuring good sealing and insulation properties without increasing the weight or cost of the packaging material.
Implementation Method 1
the product of a stress value and a thickness of the heat fusible resin layer at a time of 10% stretching is 1,200 Pa·m or more
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
A battery packaging material is formed of a laminate. The laminate is composed of an outer layer including a substrate layer, a barrier layer as an intermediate layer, and a heat fusible resin layer as an innermost layer. The total thickness of the laminate is 60 pm to 220 µm. The barrier layer is formed of a metal foil. The product of a stress value and a thickness of the heat fusible resin layer at a time of 10% stretching is 1,200 Pa·m or more.