Aluminum Alloy Foil Texture Control for Crack-Free Battery Packaging
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Solution Overview
Problem
Aluminum alloy foils with small average grain diameters, as previously developed, fail to exhibit high moldability required for modern battery packaging materials, often resulting in pinholes and cracks during molding.
Innovation Solution
An aluminum alloy foil with a cross-sectional proportion of the {111} plane of 10% or more in a face-centered cubic structure and a number average grain diameter satisfying the equation R≤0.056X+2.0, where X is the thickness of the foil, is used to enhance moldability and prevent pinholes or cracks during battery packaging material molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the aluminum alloy foil thickness is reduced to achieve lighter weight and thinner battery packaging, then weight reduction and thickness reduction are achieved, but pinholes and cracks develop during molding
Solution Approach 1:
The patent applies parameter changes by precisely controlling the aluminum alloy composition parameters (Fe: 0.01-1.0 wt%, Si: 0.01-1.0 wt%, Mn: 0.01-1.0 wt%, Mg: 0.01-0.5 wt%) and the critical crystal orientation parameter ({111} plane proportion ≥10%). By changing these material parameters, the foil achieves improved moldability and reliability at reduced thickness, preventing pinholes and cracks while maintaining weight reduction benefits.
2Manufacturing precision
If the average grain diameter is reduced to improve moldability, then grain refinement is achieved, but pinholes and cracks still occur during molding
Solution Approach 1:
The patent applies parameter changes by controlling the grain diameter within a specific range (0.003-0.06X+2.0 μm) and, more importantly, by changing the crystal orientation parameter ({111} plane proportion ≥10%). This dual parameter control ensures high moldability while preventing pinholes and cracks during molding, resolving the contradiction between manufacturing precision and reliability.
Solution Approach 2:
The patent creates a composite microstructure by combining multiple alloying elements (Fe, Si, Mn, Mg) in specific proportions with controlled grain size and crystal orientation. This composite approach at the microstructural level enhances the material's overall performance, achieving both good moldability and reliability by preventing defect formation during molding.
3Ease of manufacture
If conventional aluminum alloy compositions are used to simplify manufacturing, then manufacturing simplicity is maintained, but moldability is insufficient and pinholes/cracks occur
Solution Approach 1:
The patent applies parameter changes by optimizing the alloy composition parameters (Fe, Si, Mn, Mg contents) and crystal orientation parameter ({111} plane proportion) within specific ranges. These controlled parameter changes improve moldability while maintaining manufacturing feasibility, as the parameters can be controlled through standard metallurgical processes without requiring complex manufacturing steps.
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.