Iron-Nickel Diffusion Layer for Battery Container Corrosion
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Solution Overview
Problem
Lithium-ion battery containers face issues with corrosion resistance and nickel plating layer durability due to pitting corrosion and nickel dissolution into nonaqueous electrolytic solutions, leading to potential leakage and battery characteristic deterioration.
Innovation Solution
A surface-treated steel sheet with an iron-nickel diffusion layer formed through thermal diffusion treatment, having a molar ratio of Ni/Fe of 7.5 or less and a thickness of 0.6 μm or more, is used to prevent iron and nickel dissolution into the electrolyte, enhancing corrosion resistance and weldability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the nickel plating layer is increased to improve corrosion resistance, then the dissolution of iron into the nonaqueous electrolytic solution is suppressed, but the cost increases and the nickel plating layer drops out of the steel sheet due to the difference in ductility between iron and nickel
Solution Approach 1:
The invention changes the chemical composition parameters of the nickel plating layer by controlling the atomic percentages of specific alloying elements (Co: 3-15 at%, Cu: 3-15 at%, Zn: 3-15 at%, Al: 3-15 at%, Si: 3-15 at%, B: 3-15 at%) to achieve optimal corrosion resistance while maintaining adhesion and reducing cost
Solution Approach 2:
The invention creates a composite nickel plating layer containing multiple alloying elements (Co, Cu, Zn, Al, Si, B) combined with nickel, forming a multi-element composite structure that provides enhanced corrosion resistance and improved ductility matching with the steel substrate
2Reliability
If the thickness of the nickel plating layer is increased to prevent pitting corrosion and solution leakage, then the battery container integrity is improved, but the nickel itself may dissolve into the nonaqueous electrolytic solution depending on the type of electrolyte, thereby deteriorating the battery characteristics
Solution Approach 1:
The invention modifies the chemical composition parameters by incorporating multiple alloying elements (Co, Cu, Zn, Al, Si, B) in controlled atomic percentages to create a more stable plating layer that resists both pitting corrosion and nickel dissolution into the electrolyte
Solution Approach 2:
The invention uses alternative alloying elements that provide corrosion protection without the drawback of nickel dissolution, creating a more sustainable and chemically stable protective layer
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 the dissolution of iron and nickel, preventing pitting corrosion and leakage, while maintaining battery performance and reducing costs by ensuring the nickel plating layer does not drop off the steel sheet.
Implementation Method 1
an iron-nickel diffusion layer which is formed by performing thermal diffusion treatment after forming a nickel plating layer at least on a surface of a steel sheet to be located at an inner surface side of the battery container
Implementation Method 2
performing thermal diffusion treatment after forming a nickel plating layer... an iron-nickel diffusion layer that has an outermost layer of which the molar ratio of Ni/Fe is 7.5 or less
Data Source
AI summary
A surface-treated steel sheet for battery containers is provided. The surface-treated sheet is used to form a battery container for a battery. The battery uses a nonaqueous electrolytic solution as an electrolytic solution. The surface-treated steel sheet includes a base material made of steel and an iron-nickel diffusion layer formed by performing thermal diffusion treatment after forming a nickel plating layer at least on a surface of the base material to be located at the inner surface side of the battery container. The iron-nickel diffusion layer has an outermost layer of which a ratio of Ni and Fe is 7.5 or less as a molar ratio of Ni/Fe. The iron-nickel diffusion layer has a thickness of 0.6 μm or more.