Variable Thermal Resistance Heat Sink for Overheat Protection

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Solution Overview

Problem

Conventional heat sink devices pose risks when the cold source is not suitable for all temperature and thermal power conditions, particularly when it is made of combustible materials or sensitive to temperature rises, leading to potential overheating and electrical hazards such as electric arcs.

Innovation Solution

A heat sink device that uses a thermally conductive element whose properties change under excessive thermal conditions, increasing its thermal resistance to insulate the equipment and cold source, preventing heat and electrical energy transfer, and potentially losing contact to interrupt the thermal path.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a thermally conductive element is used to evacuate heat from equipment to a cold part, then heat evacuation efficiency is improved, but the risk of overheating the cold part increases when thermal conditions are exceeded

Engineering Contradiction:
Improveheat evacuation efficiencyVSAvoidoverheating risk of cold part
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The thermal resistance of the conductive element is made variable rather than fixed. The element dynamically adjusts its thermal resistance based on temperature conditions: low thermal resistance during normal operation for efficient heat evacuation, and high thermal resistance when thermal conditions are exceeded to prevent overheating of the cold part.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the thermal parameter (thermal resistance) of the conductive element in response to changing thermal conditions. When the temperature or thermal power exceeds predetermined thresholds, the thermal resistance increases significantly, transforming the element from a heat conductor to a thermal insulator and protecting the cold part from overheating.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the equipment and cold part are connected by a conductive element, then heat transfer is improved, but electrical insulation is compromised allowing electric arc propagation

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidelectric arc propagation
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The conductive element acts as an intermediary between the equipment and cold part. Under normal conditions, it mediates heat transfer efficiently. Under excessive thermal conditions, it transforms into a thermal insulator that also provides electrical insulation, blocking both heat and electric arc propagation while maintaining the structural connection between equipment and cold part.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the thermal resistance of the conductive element is increased to prevent overheating, then protection of the cold part is improved, but heat evacuation capability deteriorates

Engineering Contradiction:
Improveprotection of cold part from overheatingVSAvoidheat evacuation capability
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The thermal resistance is made dynamic, automatically adjusting to system conditions. During normal operation, the element maintains low thermal resistance for optimal heat evacuation. When thermal conditions exceed predetermined thresholds, the thermal resistance increases to protect the cold part, creating a self-regulating system that optimizes both heat evacuation and protection.

Inventive Principle:
Principle #15Dynamics

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

Effectively evacuates heat from equipment while preventing overheating and electrical hazards by modifying the thermal conduction properties of the element, ensuring safe operation even when thermal conditions are exceeded.

Implementation Method 1

its thermal resistance is capable of increasing under said thermal conditions so that the element becomes essentially insulating

Methodology Applied
Scientific EffectThermal resistance change: Thermal Insulation

Implementation Method 2

the element comprises at least one component of which a change of state (for example a passage from the liquid state to the gaseous state) under said thermal conditions causes said thermal resistance to increase

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 3

a passage from the liquid state to the gaseous state

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 4

the change in a mechanical property of the component during its change of state can lead to a movement of part of the element, thus causing said loss of contact

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 5

The change of state then makes it possible not only to interrupt the thermal path, but also to avoid the propagation of electrical phenomena

Methodology Applied
Scientific EffectThermal insulation by gas layer: Thermal Insulation

Data Source

PatentEP2047201B1Heat flow device
Publication Date: 2021.09.01 AIRBUS OPERATIONS (SAS)
  • EP2047201B1 patent drawingFigure 1A~3C
  • EP2047201B1 patent drawingFigure 4A~4C

AI summary

A device comprises equipment (101) with a heat source, a cold part (102) relative to the equipment, and a thermal conductor element (103) capable of conducting the heat from the equipment to the cold part. The element (103) is such that, under certain thermal conditions above a given thermal condition, the equipment and the cold part are essentially thermally isolated.