Conductive Connector with Nickel Alloy Layer for Glass Substrates

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Solution Overview

Problem

Establishing reliable electrically conductive connections between metal and glass is challenging due to differences in thermal coefficients of expansion, which can cause glass to break or crack during soldering, especially in applications like vehicle windows exposed to extreme temperatures.

Innovation Solution

A method involving a two-layer connector with a copper layer and a nickel alloy layer, where the nickel alloy has a thermal expansion coefficient closer to glass, reducing stress and using a solder with high indium content to minimize cracking, and applying pressure and heat for bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a soldered connection is established between metal and glass, then electrical conductivity is achieved, but the glass is likely to break or crack due to thermal expansion differences

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidglass cracking
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs a composite connector structure consisting of a copper base layer providing electrical conductivity and a nickel alloy overlay layer with matched thermal expansion properties. This composite material approach allows the connector to simultaneously achieve excellent electrical conductivity while accommodating thermal expansion differences between the metal and glass, thereby preventing glass cracking during soldering and under thermal stress.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the thermal expansion parameter of the connector by selecting a nickel alloy with specific compositional ratios (8-15% nickel, 0.5-2.0% manganese, 0.5-2.0% zinc, balance copper) that provide thermal expansion characteristics intermediate between copper and glass. This parameter adjustment enables the connector to bridge the thermal expansion gap, reducing stress on the glass substrate during temperature variations.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If extreme temperatures are applied to the glass-metal connection, then electrical connection is maintained, but stress on the glass increases due to thermal expansion differences

Engineering Contradiction:
Improveconnection stabilityVSAvoidthermal stress on glass
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The composite connector structure with copper base and nickel alloy overlay provides a gradual transition in thermal expansion coefficients, reducing the abrupt stress concentration at the glass-metal interface. The nickel alloy layer acts as a buffer that accommodates differential thermal expansion, thereby maintaining connection stability while minimizing thermal stress transmission to the glass during extreme temperature conditions.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent explicitly utilizes thermal expansion principles by selecting materials with complementary thermal expansion properties. The nickel alloy overlay layer has thermal expansion characteristics that are intermediate between copper and glass, allowing it to expand and contract at rates that reduce the differential stress between the metal connector and glass substrate during temperature cycling, thereby preventing glass failure.

Inventive Principle:
Principle #37Thermal expansion

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 allows for a reliable electrical connection while significantly reducing the likelihood of glass cracking during soldering and under temperature exposure, maintaining the conductivity of copper while minimizing stress on the glass substrate.

Implementation Method 1

The first material has a first coefficient of thermal expansion and the second material has a second coefficient of thermal expansion that is different than the first coefficient of thermal expansion

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

bonding the first and second layers together

Methodology Applied
Scientific EffectBonding:

Implementation Method 3

applying pressure and heat for bonding

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 4

A layer of solder is applied to the first and second layers such that the layer of solder covers the second layer and portions of the first layer that are exposed

Methodology Applied
Scientific EffectSoldering: Soldering

Data Source

PatentEP3709767B1Electrically conductive connector
Publication Date: 2023.02.08 APTIV TECHNOLOGIES LTD
  • EP3709767B1 patent drawingFigure 1
  • EP3709767B1 patent drawingFigure 2~3
  • EP3709767B1 patent drawingFigure 4

AI summary

An illustrative example method of making an electrically conductive connector (20) comprising a first material and a second material, includes situating a layer (42) comprising the second material at least partially within at least one layer (40) comprising the first material and bonding the layers together. The first material has a first coefficient of thermal expansion and the second material has a second coefficient of thermal expansion that is different than the first coefficient of thermal expansion.