Coated Battery Terminal for Stable Welding
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Solution Overview
Problem
Lithium-ion batteries face challenges in assembly and mechanical stability due to the use of different metals for positive and negative terminals, leading to connection difficulties and potential failure under operational stresses.
Innovation Solution
Coating terminals with the same metal as the terminal they connect, such as copper, nickel, or stainless steel, to ensure stable connections and weight savings, which increases energy density, using methods like galvanic, sputtering, or ion beam coating to apply the thin metal layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different metals are used for positive and negative terminals (aluminum for positive, copper/nickel for negative), then electrical conductivity and electrochemical compatibility are improved, but assembly difficulty and mechanical stability deteriorate due to welding difficulties and connection loosening under mechanical stress
Solution Approach 1:
The terminal is designed with different material properties at different locations: the core maintains the original material (aluminum or copper) for electrochemical compatibility, while the surface coating provides the matching metal material for easy welding and mechanical connection. This local differentiation resolves the contradiction between electrochemical requirements and manufacturing ease.
Solution Approach 2:
The terminal consists of a composite structure with an inner core material and an outer coating material. For example, an aluminum core with copper coating, or a copper core with nickel coating. This composite structure combines the advantages of different materials, providing both electrochemical compatibility and ease of assembly.
2Reliability
If different metals are used for positive and negative terminals, then electrochemical compatibility is improved, but mechanical stability deteriorates as connections become loose under operational stresses like oscillation
Solution Approach 1:
The terminal surface is locally modified with a coating of the same metal used for connectors, ensuring that the connection interface has optimal mechanical stability while the core material maintains electrochemical compatibility. This resolves the contradiction between electrochemical requirements and mechanical stability.
Solution Approach 2:
The metal coating acts as an intermediary layer between the terminal core and the connector. It provides a stable, matching metal surface for mechanical connection while allowing the core material to maintain its electrochemical properties, thus resolving the contradiction between electrochemical compatibility and mechanical stability.
3Reliability
If terminal coating thickness is increased to prevent defects during welding/soldering, then manufacturing reliability is improved, but weight increases which reduces energy density
Solution Approach 1:
The coating thickness is optimized to a specific range (5-20 μm) that is sufficient to prevent defects during welding and soldering while minimizing weight increase. This parameter optimization resolves the contradiction between manufacturing reliability and weight/energy density.
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 coated terminals provide improved mechanical stability and maintain electrical performance, preventing increased internal resistance and detachment issues during cycling and storage, outperforming conventional systems in mechanical tests.
Implementation Method 1
using methods like galvanic, sputtering, or ion beam coating to apply the thin metal layer
Implementation Method 2
using methods like galvanic, sputtering, or ion beam coating to apply the thin metal layer
Implementation Method 3
using methods like galvanic, sputtering, or ion beam coating to apply the thin metal layer
Data Source
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AI summary
The invention relates to an accumulator cell (20) comprising two terminals (10, 21). One terminal (10) is provided with a coating (12) made of a metal. The metal is identical to the metal of which the second terminal (21) consists, or each terminal (10, 21) is coated with a coating (12) made of the same metal. The invention further relates to an accumulator and a motor vehicle with an accumulator.