Battery Sealing Plate Coating for Adhesion and Corrosion Resistance
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Solution Overview
Problem
The adhesion strength between the base material containing Fe as a main component and the coating layer containing Al in hermetically sealed batteries is low, leading to potential cracking and exposure of the base material when the sealing plate is pressed into shape or subjected to increased internal pressure.
Innovation Solution
A hermetically sealed battery design that incorporates a sealing plate with a base material containing Fe as a main component and a coating layer containing Al and Si, which is formed on the battery inner surface of the base material to enhance adhesion strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating layer containing Al is formed on a base material containing Fe as a main component, then corrosion resistance against the electrolyte is improved, but adhesion strength between the base material and the coating layer is low
Solution Approach 1:
The patent applies composite material principle by creating a multi-layer coating structure consisting of an Al-Si alloy coating layer and an Al-Fe-Si intermetallic compound layer. This composite structure combines the corrosion resistance of Al with the adhesion benefits of Fe-Si intermetallic compounds, resolving the contradiction between corrosion resistance and adhesion strength.
Solution Approach 2:
The patent changes the chemical composition parameters of the coating layer by adding Si element and controlling the Al:Si ratio within 95:5 to 80:20 by mass. This parameter change transforms the coating from a simple Al layer with poor adhesion to an Al-Si alloy layer with improved adhesion while maintaining corrosion resistance.
2Reliability
If Al material is used for the sealing plate, then corrosion resistance against the electrolyte is achieved, but mechanical strength and pressure resistance are low
Solution Approach 1:
The patent uses composite material principle by forming a sealing plate that combines Fe base material with Al-Si coating layer. The Fe base material provides high mechanical strength and pressure resistance, while the Al-Si coating layer provides corrosion resistance, thus resolving the contradiction between corrosion resistance and mechanical strength.
3Shape
If the sealing plate is pressed into a predetermined shape, then the sealing structure is formed, but the interface between the base material and the coating layer cracks due to low adhesion strength
Solution Approach 1:
The patent applies composite material principle by creating an Al-Fe-Si intermetallic compound layer at the interface between the Fe base material and Al-Si coating layer. This intermetallic compound layer acts as a bonding layer that maintains interface integrity during the pressing process, preventing cracks while allowing the sealing structure to be formed.
Data Source
AI summary
Provided is a hermetically sealed battery comprising a sealing plate having improved adhesion strength between an Al-containing coating layer and a substrate containing Fe as a main component. The hermetically sealed battery comprises a bottomed cylindrical outer can having an opening and containing an electrode assembly and an electrolyte; and a sealing plate blocking the opening of the outer can, wherein the sealing plate has a substrate containing Fe as a main component, and an Al- and Si-containing coating layer formed on the battery inner surface of the substrate.