Fe-Ni Diffusion Layer Control for Corrosion-Resistant Battery Containers
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Solution Overview
Problem
As battery capacity increases, the potential of the Fe-Ni diffusion layer in traditional surface-treated steel sheets becomes close to the positive electrode potential, leading to iron elution into the electrolyte solution and corrosion of the battery container during overdischarge, necessitating a steel sheet with higher electrolyte solution resistance.
Innovation Solution
A surface-treated steel sheet with an Fe-Ni diffusion layer is developed, where the ratio of maximum diffraction intensities at specific angles is controlled through thin film X-ray diffractometry, and the thickness and composition of the diffusion layer are optimized to suppress iron elution and enhance electrolyte solution resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional Fe-Ni diffusion layer is used in surface-treated steel sheets, then pitting corrosion and solution leakage are prevented, but iron elution occurs during overdischarge when battery capacity increases
Solution Approach 1:
The invention changes the crystallographic parameters of the Fe-Ni diffusion layer by controlling the ratio of maximum diffraction intensities (Ib/Ia) at specific angles within 0.01 to 0.37, and adjusting the full width at half maximum (FWHM) of peak A to 0.35 or more. These parameter changes modify the diffusion layer's structure to reduce iron elution during overdischarge while maintaining corrosion resistance
Solution Approach 2:
The invention creates a composite surface structure consisting of the steel sheet substrate and the Fe-Ni diffusion layer with specific crystallographic characteristics. The diffusion layer acts as a protective barrier that combines the benefits of corrosion prevention with reduced iron elution, forming a composite material system with enhanced overall performance
2Quantity of substance
If the positive electrode potential increases with battery capacity, then battery energy storage improves, but the potential difference between the Fe-Ni diffusion layer and positive electrode decreases, causing iron elution
Solution Approach 1:
The invention modifies the physical and chemical parameters of the Fe-Ni diffusion layer, specifically the crystallographic orientation indicated by the diffraction intensity ratio (Ib/Ia) and peak broadening (FWHM). These parameter changes enhance the diffusion layer's stability and electrolyte solution resistance, allowing it to withstand higher positive electrode potentials without iron elution even as battery capacity increases
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 iron elution and enhances electrolyte solution resistance during overdischarge, ensuring the integrity and performance of the battery container.
Implementation Method 1
an Fe-Ni diffusion layer formed on the topmost surface of at least one surface of the steel sheet
Data Source
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AI summary
Provided is a surface-treated steel sheet comprising a steel sheet, and an Fe-Ni diffusion layer formed on the topmost surface of at least one surface of the steel sheet, wherein when a maximum diffraction intensity IA at a diffraction angle 2θ of 43.00° or more and 44.30° or less and a maximum diffraction intensity IB at a diffraction angle 2θ of 44.51° or more and 45.00° or less are obtained by thin film X-ray diffractometry performed on the surface of the Fe-Ni diffusion layer, the ratio IB/IA is 0.01 ≤ IB/IA ≤ 0.37.