Power Cable Intermetallic Layer Thickness Control
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Solution Overview
Problem
The challenge is to prevent brittle fracture in the connecting parts of power cables due to tensile forces, particularly in the interface between copper and aluminum conductors, where an intermetallic compound layer forms, which can lead to mechanical and electrical property degradation, especially under conditions of direct current transmission and dynamic submarine power applications.
Innovation Solution
A power cable system is developed where the average thickness of the intermetallic compound layer at the bonding surfaces of copper and aluminum conductors is maintained at or below 10 μm, using resistance welding to bond the conductors, ensuring the layer does not exceed a critical thickness that causes brittle fracture, and the conductors are processed to minimize voids and oxide films for improved bonding quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resistance welding is used to bond copper and aluminum conductors, then electrical connectivity is achieved, but an intermetallic compound layer forms that can cause brittle fracture
Solution Approach 1:
The patent applies parameter changes by controlling the thickness of the intermetallic compound layer to be less than or equal to 10 μm through resistance welding process optimization. This thickness control prevents the layer from reaching critical thickness that causes brittle fracture, while still maintaining adequate electrical connectivity between copper and aluminum conductors.
2Strength
If the intermetallic compound layer thickness increases, then bonding strength initially improves, but brittle fracture risk increases when thickness exceeds critical value
Solution Approach 1:
The patent identifies and controls the critical parameter of intermetallic compound layer thickness, setting it to be less than or equal to 10 μm. This parameter control optimizes the balance between bonding strength and brittle fracture resistance by preventing the layer from exceeding the critical thickness that triggers brittle fracture.
3Loss of energy
If direct current transmission is used to reduce transmission losses, then energy efficiency improves, but electromigration accelerates intermetallic compound layer growth
Solution Approach 1:
The patent applies preliminary anti-action by pre-controlling the intermetallic compound layer thickness to be less than or equal to 10 μm before electromigration can significantly accelerate its growth. This preventive approach counteracts the harmful effect of electromigration-induced layer thickening that would otherwise occur during direct current transmission.
4Ease of manufacture
If aluminum conductors are used instead of copper to reduce cost, then material cost decreases, but electrical conductivity and mechanical properties are reduced
Solution Approach 1:
The patent uses a composite material approach by bonding aluminum and copper conductors together through resistance welding with controlled intermetallic compound layer formation. This composite structure combines the cost advantage of aluminum with the superior electrical and mechanical properties of copper, achieving a balance between material cost and performance reliability.
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
This approach effectively determines the risk of brittle fracture and minimizes unnecessary costs and design changes by maintaining the intermetallic compound layer thickness below the critical threshold, ensuring the power cable's durability and stability, even in harsh environments like submarine applications.
Implementation Method 1
bonded by resistance welding
Implementation Method 2
bonded by resistance welding
Implementation Method 3
intermetallic compound layer formed as a result of a material migration phenomenon at bonding surfaces
Implementation Method 4
electromigration effect, a phenomenon of material movement due to the continuous movement of ions in the conductor that occurs due to the transfer of momentum between conduction electrons and scattered atomic nuclei in the metal under the condition of direct current electrical application
Data Source
AI summary
The present disclosure relates to a power cable system capable of determining the possibility of brittle fracturing of a different conductor connecting part of power cables due to tensile force applied to the different conductor connecting part, the power cable system comprising: a first conductor constituting a first power cable; a second conductor constituting a second power cable; and the different conductor connecting part formed by bonding the first conductor and the second conductor by means of resistance welding, wherein the average thickness of an intermetallic compound layer formed on the bonding surface of the different conductor connecting part is 10 μm or less, which is the critical average thickness at which a brittle fracture occurs during a tensile test.