Dissimilar Metal Grounding Device Prevents Galvanic Corrosion

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Solution Overview

Problem

Existing methods for coupling dissimilar metal vehicle components, such as aluminum and steel, using bonding straps often result in galvanic corrosion due to the incompatibility of the materials, leading to destructive reactions and reduced electrical contact.

Innovation Solution

An electrical grounding device comprising adjacent plate portions made from dissimilar metals, where one surface is fabricated from aluminum and the other from steel, are folded together to create a corrosion-free bond, ensuring each surface contacts a component of the same metal type, thereby preventing galvanic reactions and facilitating electrical connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If bonding straps with dissimilar metal lugs are used to couple different metal components, then electrical conductivity is optimized, but galvanic corrosion occurs at the lug interfaces

Engineering Contradiction:

Improveelectrical conductivityVSAvoidcorrosion resistance

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The bonding strap is designed with different metal materials at different locations: copper cable for optimal electrical conductivity in the central region, and aluminum or steel lugs at the ends for metallurgical compatibility with specific components. This local differentiation allows the strap to simultaneously achieve high electrical conductivity where needed and corrosion resistance at the component interfaces.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The bonding strap employs a composite structure combining copper cable with aluminum or steel lugs. This composite material approach allows the strap to leverage the high electrical conductivity of copper while using corrosion-resistant aluminum or steel at the interfaces with dissimilar metal components, thereby resolving the contradiction between conductivity and corrosion resistance.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If lugs of different metal types are attached to ends of copper cable, then metallurgical compatibility with different components is achieved, but crevices and interstices are created that accelerate corrosion

Engineering Contradiction:

Improvemetallurgical compatibilityVSAvoidlocalized corrosion

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

3Reliability

If conventional welding is used to join different metals in the bonding strap, then strong electrical connection is achieved, but welding difficulty increases due to dissimilar metals

Engineering Contradiction:

Improveelectrical connection strengthVSAvoidwelding difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The copper cable acts as an intermediary element between aluminum and steel components. Rather than directly welding dissimilar metals (aluminum to steel), the copper cable provides a intermediate connection point that can be separately joined to each metal type using appropriate welding or bonding methods, thereby simplifying the manufacturing process while maintaining strong electrical connections.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 reduces or prevents galvanic corrosion and maintains electrical contact between dissimilar metal components, providing a reliable grounding path with improved conductance and reduced resistance, thus minimizing the need for extensive copper wiring and preventing corrosion at connection points.

Implementation Method 1

The first plate portion is folded onto the second plate portion such that a portion of the first surface of the first plate portion contacts a portion of the first surface of the second plate portion

Methodology Applied

Scientific EffectFolding: Folding

Implementation Method 2

the body electrically coupling the first component and the second component to facilitate electrically connecting the first and second components

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS9083089B2Electrical grounding and structural device for dissimilar metal components

Publication Date: 2015.07.14 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

In one exemplary embodiment of the invention, an electrical grounding device for dissimilar metals is provided. The device includes a body comprising adjacent first and second plate portions, the body including a first surface formed from a first metal and an opposite second surface formed from a second metal. The first plate portion is folded onto the second plate portion such that a portion of the first surface of the first plate portion contacts a portion of the first surface of the second plate portion. The first surface of the first plate portion is configured to couple to a first component formed from the first metal and the second surface of the second plate portion is configured to couple to a second component formed from the second metal, the body electrically coupling the first component and the second component to facilitate electrically connecting the first and second components.