Battery Can Steel Sheet With Fe-Ni Diffusion Layer for Corrosion Resistance
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Solution Overview
Problem
Conventional surface-treated steel sheets for battery containers face issues with corrosion resistance when the thickness of the can wall is reduced, leading to increased iron dissolution and decreased corrosion resistance, especially when the nickel plating layer is thin or the heat treatment conditions are severe.
Innovation Solution
A surface-treated steel sheet with an iron-nickel diffusion layer and a nickel layer, where the thickness of the iron-nickel diffusion layer is between 0.04 to 0.31 μm and the total nickel content is 10.8 to 26.7 g/m², formed through a nickel plating step followed by a heat treatment at 450 to 600°C for 30 seconds to 2 minutes, enhancing corrosion resistance while allowing for thinner can walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the can wall is reduced to improve volume percentage, then the volume percentage is improved, but the corrosion resistance is decreased due to increased iron dissolution
Solution Approach 1:
The invention changes the parameters of the surface treatment layer, specifically controlling the thickness of the iron-nickel diffusion layer (0.03 to 0.30 μm) and the total nickel content (10.8 to 26.7 g/m²), to maintain corrosion resistance even when the can wall thickness is reduced
Solution Approach 2:
The invention uses a composite surface treatment structure consisting of multiple layers (nickel plating layer, iron-nickel diffusion layer, and nickel layer) to achieve both reduced can wall thickness and maintained corrosion resistance through the synergistic effect of different material layers
2Stability of the object's composition
If conventional heat treatment conditions (high temperature or long time) are used to form the iron-nickel diffusion layer, then the diffusion layer is formed, but the inter-diffusion between iron and nickel increases excessively, leading to increased iron dissolution and decreased corrosion resistance
Solution Approach 1:
The invention optimizes the heat treatment parameters (temperature and time) to control the diffusion process, achieving the desired iron-nickel diffusion layer thickness (0.03 to 0.30 μm) without excessive inter-diffusion that would compromise corrosion resistance
Solution Approach 2:
The invention applies a controlled amount of heat treatment (not excessive) to achieve the necessary diffusion layer formation while avoiding over-diffusion that would lead to increased iron dissolution
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 provides a surface-treated steel sheet with improved corrosion resistance and processability, even when the can wall thickness is reduced, by controlling the iron-nickel diffusion layer thickness and nickel content, thereby balancing volume percentage and corrosion resistance in battery containers.
Implementation Method 1
forming an iron-nickel diffusion layer by applying a heat treatment to the nickel plated steel sheet
Implementation Method 2
when the Fe intensity and the Ni intensity are continuously measured along the depth direction from the surface of the surface-treated steel sheet for a battery container, by using a high frequency glow discharge optical emission spectrometric analyzer
Data Source
AI summary
A surface-treated steel sheet for a battery container includes a steel sheet, an iron-nickel diffusion layer formed on the steel sheet, and a nickel layer formed on the iron-nickel diffusion layer and constituting the outermost layer. When the Fe intensity and the Ni intensity are continuously measured from the surface of the surface-treated steel sheet for a battery container along the depth direction with a high frequency glow discharge optical emission spectrometric analyzer, the thickness of the iron-nickel diffusion layer being the difference (D2−D1) between the depth (D1) at which the Fe intensity exhibits a first predetermined value and the depth (D2) at which the Ni intensity exhibits a second predetermined value is 0.04 to 0.31 μm; and the total amount of the nickel contained in the iron-nickel diffusion layer and the nickel contained in the nickel layer is 10.8 to 26.7 g/m2.