Aluminum Alloy Foil Texture Control for Crack-Resistant Battery Packaging
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Solution Overview
Problem
Existing aluminum alloy foils used in battery packaging materials suffer from pinhole and crack formation during molding, despite having small average grain diameters, failing to meet the required high moldability standards.
Innovation Solution
An aluminum alloy foil with a specific crystal plane proportion and grain diameter relationship, where the {111} plane area is 10% or more and the number average grain diameter satisfies the equation number average grain diameter R≤0.056X+2.0, where X is the foil thickness, is used to enhance moldability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a film-shaped battery packaging material with aluminum alloy foil is used to reduce thickness and weight, then weight reduction is achieved, but pinholes and cracks develop during molding
Solution Approach 1:
The invention changes the crystallographic parameters of the aluminum alloy foil by controlling the proportion of {111} crystal planes (orientational parameter) and adjusting the grain diameter according to a specific formula. This parameter transformation enables the material to maintain high reliability during molding while achieving weight reduction through thinner foil gauge.
2Length of moving object
If the aluminum alloy foil thickness is reduced to achieve thinner packaging, then weight and thickness reduction are achieved, but moldability deteriorates with increased pinhole and crack formation
Solution Approach 1:
The invention applies parameter changes by establishing a specific relationship between grain diameter and thickness (R≤0.056X+2.0), and controlling the {111} crystal plane proportion. This allows the foil to be made thinner while maintaining excellent moldability through optimized crystal structure that prevents defect formation during forming.
3Stability of the object's composition
If conventional aluminum alloy foil with small average grain diameter is used, then grain refinement is achieved, but high moldability is not attained and pinholes and cracks still form
Solution Approach 1:
The invention transforms the material properties by changing not just the grain size but specifically the crystallographic orientation distribution, controlling the proportion of {111} planes. This orientational parameter change, combined with grain diameter control according to the specified formula, achieves high moldability that conventional grain refinement alone cannot provide.
Data Source
AI summary
Aluminum alloy foil that, when used for battery packaging material, unlikely to develop pinholes or cracks even during molding of battery packaging material, and can exhibit excellent moldability. Aluminum alloy foil, which is for use in battery packaging material, wherein, with respect to cross section obtained by cutting aluminum alloy foil in vertical direction to rolling direction of aluminum alloy foil, which is a vertical direction to surface of aluminum alloy foil, proportion of total area of a {111} plane in total area of crystal planes of face-centered cubic structure, obtained by performing crystal analysis using EBSD method, is 10% or more; and with respect to cross section, a number average grain diameter R (μm) of crystals in face-centered cubic structure, obtained by performing crystal analysis using EBSD method, satisfies following equation: number average grain diameter R≤0.056X+2.0, where X=thickness (μm) of aluminum alloy foil.