Fuel Cell Separator Aluminum Sheet Texture for Thin-Gauge Formability
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Solution Overview
Problem
Aluminum sheet materials for fuel cell separators face challenges in achieving sufficient yield strength and elongation while maintaining a thickness of 0.5 mm or less, which affects their formability and corrosion resistance.
Innovation Solution
An aluminum sheet material with a composition of 9-10 wt% Mg, balanced with Al and inevitable impurities, and optionally including up to 0.12 wt% Mn and Cr, is manufactured using a process involving casting, extrusion, cold rolling, and thermal treatment to achieve a cube texture and rotated cube texture, resulting in improved yield strength and elongation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a separator is made of aluminum substance to achieve weight reduction, then corrosion resistance is improved, but yield strength and elongation deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the aluminum alloy by precisely controlling the content of alloying elements (Mg: 9-10 wt%, Mn: 0.05-0.12 wt%, Cr: 0.05-0.12 wt%, Si: 0.05-0.15 wt%, Fe: 0.05-0.15 wt%, Ti: 0.02-0.05 wt%, B: 0.001-0.005 wt%) to achieve the desired balance between corrosion resistance and mechanical properties
Solution Approach 2:
The patent creates a composite microstructure within the aluminum alloy by forming specific precipitate phases (Al3Mg2, Al6Mn, Al7Cr3Si2, Al-Fe-Si intermetallic compounds, and TiB2 particles) that work together to simultaneously provide corrosion resistance and enhanced mechanical strength
2Strength
If aluminum sheet material fails to meet necessary yield strength and elongation, then formability deteriorates, but thickness requirement of 0.5 mm or less remains
Solution Approach 1:
The patent optimizes processing parameters including casting temperature, rolling reduction rate, and thermal treatment conditions (heating to 350-450°C and holding for 5-30 minutes) to control the formation of cube and rotated cube textures, which dramatically improve formability while maintaining high strength
Solution Approach 2:
The patent creates local variations in microstructure by controlling the distribution and size of precipitate phases throughout the material, with fine dispersoid particles providing local strengthening without compromising overall ductility and formability
3Weight of moving object
If separator thickness is reduced to 0.5 mm or less, then weight reduction is achieved, but formability and mechanical properties deteriorate
Solution Approach 1:
The patent applies specific thermal treatment parameters (heating to 350-450°C and holding for 5-30 minutes) that promote the formation of cube and rotated cube crystal orientations, which are known to dramatically improve formability and enable successful processing of thin sheets at 0.5 mm or less thickness
Solution Approach 2:
The patent performs preliminary thermal treatment and texture control during manufacturing to pre-establish the optimal crystal orientation and microstructure before the actual forming operations, ensuring that the thin material can be successfully formed without defects
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 aluminum sheet material exhibits yield strength of 150 MPa or higher and elongation of 28% or more, enabling effective formability and corrosion resistance, thus suitable for lightweight fuel cell separators.
Implementation Method 1
cold-pack rolling the rolled plate to prepare a sheet material, with multiple copies of the rolled plate being stacked; and thermally treating the sheet material
Implementation Method 2
the aluminum sheet material may have Al3Mg2 formed as a precipitation phase therein
Data Source
AI summary
According to an embodiment, the aluminum sheet material for a separator of a fuel cell is used for forming a separator applied to a fuel cell stack and comprises 9-10 wt % of Mg; and the balance of Al and inevitable impurities, wherein the aluminum sheet material has cube texture and an R-cube texture formed therein. An aluminum sheet material for a separator in a fuel cell retains a thickness of 0.5 mm or less and exhibits excellent yield strength and elongation, and a manufacturing method therefor.