Flat Flexible Harness Circuits for Heat Dissipation and Low Profile

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Solution Overview

Problem

Conventional electrical harnesses using round wires are bulky, heavy, and expensive due to resistive heating and thermal dissipation issues, making them unsuitable for applications requiring smaller, lighter, and less expensive components.

Innovation Solution

The use of flat conductor traces formed from a sheet of metal with a high width-to-thickness ratio, allowing for flexible and thermally coupled harnesses that can be conformal to various surfaces, with connections formed through crimping, welding, and folding techniques to maintain a low thickness profile.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If round wires with larger cross-sectional sizes are used to transmit electrical power, then resistive heating and thermal dissipation are improved, but the harness becomes bulkier and heavier

Engineering Contradiction:
Improvethermal dissipationVSAvoidharness weight
Core Design Contradiction:
TemperatureVSWeight of stationary object

Solution Approach 1:

The patent changes the geometric parameters of the conductor from round cross-section to flat ribbon cross-section. This parameter change allows the same electrical current capacity to be achieved with a thinner profile, improving thermal dissipation to the environment while reducing overall harness thickness and weight.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention transitions from one-dimensional wire thickness to two-dimensional flat ribbon geometry. By spreading the conductor in the width dimension rather than increasing thickness, the harness achieves better thermal dissipation surface area without proportionally increasing weight or volume.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Temperature

If round wires with larger cross-sectional sizes are used to transmit electrical power, then resistive heating and thermal dissipation are improved, but the harness becomes bulkier

Engineering Contradiction:
Improvethermal dissipationVSAvoidharness volume
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The patent changes the geometric parameters of the conductor from round cross-section to flat ribbon cross-section. This parameter change allows the same electrical current capacity to be achieved with a thinner profile, improving thermal dissipation to the environment while reducing overall harness thickness and weight.

Inventive Principle:
Principle #35Parameter changes

3Power

If conventional round wires are used in harnesses, then electrical power transmission is achieved, but the harnesses become expensive to manufacture

Engineering Contradiction:
Improveelectrical power transmissionVSAvoidmanufacturing cost
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The patent changes the geometric parameters of the conductor from round cross-section to flat ribbon cross-section. This parameter change allows the same electrical current capacity to be achieved with a thinner profile, improving thermal dissipation to the environment while reducing overall harness thickness and weight.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention merges multiple conductor functions into a single flat ribbon structure that provides both electrical conduction and thermal management. This integration reduces the number of separate components needed, simplifying assembly and reducing manufacturing costs.

Inventive Principle:
Principle #5Merging (Combining)

4Temperature

If flat conductor traces with high width-to-thickness ratio are used, then thermal dissipation and conformality are improved, but connection to connectors becomes more difficult

Engineering Contradiction:
Improveheat transferVSAvoidconnection ease
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The patent applies different geometric properties to different parts of the conductor. The main conductor trace has a high width-to-thickness ratio for optimal thermal dissipation and conformality, while the connecting end is formed with a lower width-to-thickness ratio and different geometry to facilitate easy connection to conventional round-wire connectors.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The conductor is segmented into distinct functional zones: a long conductor trace portion optimized for thermal dissipation with high width-to-thickness ratio, and a separate connecting end portion optimized for connector attachment with lower width-to-thickness ratio. This segmentation allows each portion to be optimized for its specific function.

Inventive Principle:
Principle #1Segmentation

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 flexible and thermally coupled harnesses reduce weight, size, and cost by using smaller cross-sectional areas, enabling conformality and efficient heat dissipation, while maintaining robust electrical connections.

Implementation Method 1

enhances heat transfer from the harness to the environment

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

enhances heat transfer from the harness to the environment

Methodology Applied
Scientific EffectThermal convection: Convection

Data Source

PatentEP3580097B1Flexible circuits for electrical harnesses
Publication Date: 2025.11.12 CELLINK CORP
  • EP3580097B1 patent drawingFigure 1A~1B
  • EP3580097B1 patent drawingFigure 2A~3C
  • EP3580097B1 patent drawingFigure 4A~4B

AI summary

Provided are electrical harness assemblies and methods of forming such harness assemblies. A harness assembly comprises a conductor trace, comprising a conductor lead with a width-to-thickness ratio of at least 2. This ratio provides for a lower thickness profile and enhances heat transfer from the harness to the environment. In some examples, a conductor trace may be formed from a thin sheet of metal. The same sheet may be used to form other components of the harness. The conductor trace also comprises a connecting end, monolithic with the conductor lead. The width-to-thickness ratio of the connecting end may be less than that of the conductor trace, allowing for the connecting end to be directly mechanically and electrically connected to a connector of the harness assembly. The connecting end may be folded, shaped, slit-rearranged, and the like to reduce its width-to-thickness ratio, which may be close to 1.