Battery Packaging Material Anti-Curling Laminate Design
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Solution Overview
Problem
Battery packaging materials with reduced thickness face challenges in maintaining moldability, preventing pinholes and cracks, and avoiding curling, which affects the productivity and energy density of batteries, especially in large secondary batteries.
Innovation Solution
A battery packaging material with a laminate structure comprising a base material layer, adhesive layer, metal layer, and heat-sealable resin layer, where the base material layer has a tensile elastic modulus of 400 N/15 mm or more and 1000 N/15 mm or less in both directions, and a small absolute difference in moduli, ensuring excellent moldability and inhibiting curling after molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the thickness of the battery packaging material is reduced to achieve thinning and weight reduction, then weight reduction and thickness reduction are achieved, but pinholes and cracks are easily generated during molding and curling occurs after molding
Solution Approach 1:
The patent employs a multi-layer composite structure consisting of a base material layer, metal layer, and heat-sealable resin layer. This composite structure combines the advantages of different materials: the base material provides dimensional stability and prevents curling, the metal layer provides barrier properties and strength, and the heat-sealable resin layer provides sealing capability. This resolves the contradiction by maintaining structural integrity while enabling thinning.
Solution Approach 2:
The patent specifies precise parameter ranges for the base material layer, including tensile elastic modulus (300-1000 N/15mm in machine direction, 200-800 N/15mm in transverse direction) and thickness (5-30 μm). By optimizing these parameters, the base material layer maintains sufficient rigidity to prevent curling and pinhole formation during molding, while enabling overall thinning of the packaging material.
2Length of stationary object
If the thickness of the battery packaging material is reduced to achieve thinning, then thickness reduction is achieved, but the peripheral edge of concave portion curls and heat-welding is hindered
Solution Approach 1:
The patent optimizes the tensile elastic modulus of the base material layer within specific ranges (300-1000 N/15mm in machine direction, 200-800 N/15mm in transverse direction) and controls thickness (5-30 μm). These parameter changes ensure the material maintains sufficient rigidity to prevent edge curling during molding, creating flat surfaces that enable proper heat-welding contact and processability.
Solution Approach 2:
The patent applies different material properties to different layers: the base material layer provides dimensional stability and anti-curling properties, while the heat-sealable resin layer provides sealing functionality. This local differentiation of material qualities ensures that each layer performs its specific function optimally, with the base layer preventing curling to enable proper heat-welding of the resin layer.
3Length of stationary object
If the thickness of the battery packaging material is reduced to achieve thinning and weight reduction, then thickness and weight are reduced, but pinholes and cracks are easily generated during molding
Solution Approach 1:
The multi-layer composite structure with base material layer (5-30 μm), metal layer, and heat-sealable resin layer provides distributed structural support. The base material layer's optimized tensile elastic modulus prevents stress concentration during molding, eliminating pinholes and cracks while enabling thinning. The composite structure maintains manufacturing precision despite reduced thickness.
Solution Approach 2:
By controlling the tensile elastic modulus of the base material layer within specific ranges and optimizing its thickness (5-30 μm), the patent ensures the material has sufficient rigidity to maintain structural integrity during molding operations. This prevents pinhole and crack formation while achieving overall thinning of the packaging material.
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 suppresses the generation of pinholes and cracks during molding and prevents curling, enhancing the productivity and energy density of batteries while maintaining a thin, lightweight design.
Implementation Method 1
a tensile elastic modulus of the base material layer in each of one direction and other direction orthogonal to the one direction on the same plane is 400 N/15 mm or more and 1000 N/15 mm or less, and an absolute value of a difference between the tensile elastic moduli of the base material layer in the one direction and the other direction is 150 N/15 mm or less
Implementation Method 2
a battery packaging material including a laminate including at least a base material layer, an adhesive layer, a metal layer and a heat-sealable resin layer
Implementation Method 3
heat-sealable resin layers are heat-welded to obtain a battery with battery elements stored in the battery packaging material
Data Source
AI summary
A packaging material for batteries, which is not susceptible to the formation of a pinhole or cracking during the forming, while having excellent formability, and is effectively suppressed in curling after the forming, which is formed of a laminate with at least a base layer, an adhesive layer, a metal layer and a thermally fusible resin layer in this order, and wherein: the tensile modulus of elasticity of the base layer in one direction and the tensile modulus of elasticity of the base layer in a perpendicular direction in the same plane are both within the range of from 400 N/15 mm to 1,000 N/15 mm (inclusive); and the absolute value of the difference between the tensile modulus of elasticity of the base layer in the one direction and the tensile modulus of elasticity of the base layer in the other is 150 N/15 mm or less.