Heating Element Busbar Contact Resistance Reduction

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Solution Overview

Problem

Existing heating elements face issues with high surface resistance and local heat generation due to the placement of busbars on heating patterns, leading to increased resistance values and inefficient heat distribution.

Innovation Solution

The busbar is positioned on a conductive layer area with a higher pattern density than the heating pattern, using an adhesive layer with conductive materials to minimize contact resistance and prevent local heat generation, while maintaining high aperture ratios for efficient heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If busbars are positioned on heating pattern areas to connect heating elements, then electrical connection is achieved, but contact resistance increases and local heat generation occurs

Engineering Contradiction:
Improveelectrical connectionVSAvoidcontact resistance and local heat
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a conductive layer as an intermediary between the busbar and the heating pattern. This conductive layer has higher conductivity than the heating pattern material, serving as a mediator that reduces contact resistance and prevents local heat generation at the connection interface while maintaining reliable electrical connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies different material properties to different regions: the conductive layer is specifically positioned at the busbar connection areas with high conductivity, while the heating pattern areas maintain their original heating properties. This local differentiation optimizes both connection reliability and heating performance without compromising either function.

Inventive Principle:
Principle #3Local quality

2Power

If transparent conductive materials like ITO or Ag thin film are used to form heating layers, then heating function is achieved, but surface resistance becomes high preventing low voltage operation

Engineering Contradiction:
Improveheating functionVSAvoidsurface resistance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent uses composite material structures combining transparent conductive materials (ITO or Ag thin film) with additional conductive layers. This composite approach maintains the transparency and heating function of the original materials while adding layers that reduce overall surface resistance, enabling low voltage operation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the electrical parameters of the heating layer by adding conductive layers, changing the surface resistance from high to low values. This parameter change enables the system to operate at low voltages while maintaining adequate heating function through adjusted current characteristics.

Inventive Principle:
Principle #35Parameter changes

3Power

If metal wire is used for heating at low voltage with increased current, then heating power is achieved, but contact resistance and heat generation in busbar become critical problems

Engineering Contradiction:
Improveheating powerVSAvoidheat loss in busbar and contact resistance
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The conductive layer acts as an intermediary that reduces contact resistance between the busbar and metal wire heating element. By providing a low-resistance interface, it minimizes energy loss at the connection point, allowing high current operation without excessive heat generation in the busbar.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the electrical parameters at the connection interface by introducing the conductive layer, reducing contact resistance and thereby reducing I²R losses. This enables efficient high-current operation necessary for low-voltage heating applications.

Inventive Principle:
Principle #35Parameter changes

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 reduces resistance values between busbars and prevents local heat generation, enabling effective heat distribution and efficient operation at lower voltages, suitable for applications in vehicles and display devices.

Implementation Method 1

the conductive layer area, and the busbar positioned on the conductive layer area

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

heat is generated from a heating wire by applying electricity to both terminals of the heating wire

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

a temperature of the glass surface is increased by the generated heat

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Data Source

PatentEP2928264B1Heating element and method for manufacturing same
Publication Date: 2019.07.24 LG CHEM LTD
  • EP2928264B1 patent drawingFigure 1
  • EP2928264B1 patent drawingFigure 2
  • EP2928264B1 patent drawingFigure 3

AI summary

Provided are a heating element including: a substrate; a conductive heating unit provided on the substrate; and two busbars provided to apply voltages to both ends of the conductive heating unit, respectively, in which the conductive heating unit includes a conductive heating pattern area and two conductive layer areas provided at both ends of the conductive heating pattern area, and the two busbars are provided on the conductive layer areas, respectively, and a method of preparing the same.