Shielded Connector Galvanic Corrosion Insulation
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Solution Overview
Problem
Shielded connectors in hybrid electric vehicles and electric vehicles face a risk of galvanic corrosion at the bimetallic contact between copper or copper alloy braided conductors and stainless steel shield rings, which can reduce the shielding effect.
Innovation Solution
Incorporating an insulation layer, specifically an acetate tape formed of semisynthetic fibers made of acetylcellulose, between the braided conductor and the shield ring to prevent direct contact and thus galvanic corrosion, ensuring the braided conductor and shield ring remain insulated and electrically connected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a shield ring made of stainless steel is used to clamp the braided conductor to the shield shell, then the mechanical strength and clamping force are improved, but galvanic corrosion occurs due to bimetallic contact between the stainless steel shield ring and copper braided conductor, reducing the shielding effect
Solution Approach 1:
An insulation layer made of resin or rubber is introduced as an intermediary between the stainless steel shield ring and copper braided conductor. This intermediate layer prevents direct contact between the dissimilar metals, eliminating the galvanic corrosion pathway while allowing the shield ring to maintain its clamping function on the braided conductor.
Solution Approach 2:
The insulation layer, which initially might seem to reduce clamping effectiveness by adding a barrier, actually converts the harmful galvanic corrosion into a beneficial protective measure. The insulating material prevents electrochemical reactions while the swaging process deforms the shield ring to achieve sufficient mechanical attachment force through the insulation layer.
2Reliability
If the shield ring is swaged directly to the braided conductor without an insulation layer, then the electrical conductivity and mechanical connection are improved, but galvanic corrosion occurs between different metal materials, reducing long-term reliability
Solution Approach 1:
The insulation layer serves as a mediator that separates the dissimilar metals (stainless steel shield ring and copper braided conductor) to prevent galvanic corrosion. This intermediate layer allows the connection to maintain its integrity over time by eliminating the electrochemical reaction pathway that would otherwise degrade the connection.
Solution Approach 2:
The insulation layer is applied beforehand to the braided conductor before the shield ring is swaged onto it. This pre-application of protective insulation cushions against the harmful effect of galvanic corrosion before it can occur, ensuring long-term durability of the electrical connection.
3Duration of action of stationary object
If an insulation layer is added between the braided conductor and shield ring, then galvanic corrosion is prevented and long-term reliability is improved, but the device complexity and manufacturing steps increase
Solution Approach 1:
The insulation layer application and shield ring installation processes are merged into a single operational step. The insulation layer is applied to the braided conductor, and then the shield ring is immediately swaged onto it in sequence, combining what could be separate operations into an integrated manufacturing process that minimizes additional complexity.
Solution Approach 2:
The insulation layer serves multiple functions simultaneously: it provides electrical insulation, prevents galvanic corrosion between dissimilar metals, and acts as a bonding interface for the swaging process. This multi-functionality reduces the need for additional separate components or processes.
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 configuration effectively maintains an excellent shielding effect by preventing galvanic corrosion, ensuring high performance and quality over a long period by insulating the braided conductor and shield ring from each other, even when made of different metals.
Implementation Method 1
the portion where the braided conductor is in contact with the shield ring has a bimetallic contact, and there is a possibility that galvanic corrosion may occur
Implementation Method 2
an insulation layer is provided between the braided conductor and the shield ring
Data Source
AI summary
The male shielded connector of the invention includes terminals which are connected to end portions of electric wires, a housing which contains the terminals, a shield shell which covers the housing, a braided conductor which is externally provided to the wire and is covered on the shield shell, and a shield ring which is swaged to the outer circumference of the braided conductor to fix the braided conductor in a state that the braided conductor is electrically connected to the shield shell, the shield ring being made of a metal material. An insulation layer is provided between the braided conductor and the shield ring.