Carbon Nanotube Thin Film Resistive Heater

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Solution Overview

Problem

Existing laminated resistive heating devices face challenges in achieving high reliability and durability, especially in harsh environments, due to issues with adhesion and interference from bulky copper leads, and the impact of solvents on carbon nanotube electrical properties.

Innovation Solution

A laminated resistive heater with a substantially polymer-free carbon nanotube layer, applied to a grooved substrate with a solventless polyurethane protective coating, and electrical leads integrated directly onto the substrate, enhancing adhesion and durability while maintaining low electrical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a polymer-based resistive heating layer with carbon nanotube filler is used, then the heater can be manufactured using conventional coating processes, but the polymer matrix interferes with the electrical properties of carbon nanotubes and reduces reliability in harsh environments

Engineering Contradiction:
ImprovemanufacturabilityVSAvoidreliability in harsh environments
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent extracts and removes the polymer matrix from the carbon nanotube heating layer, leaving a substantially polymer-free CNT network. This extraction eliminates the harmful interference of polymer on CNT electrical properties while maintaining the manufacturability through direct deposition of CNT networks onto substrates using techniques like chemical vapor deposition or screen printing of CNT pastes.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a composite structure where a carbon nanotube network is integrated directly with the substrate, eliminating the need for a polymer matrix. The CNTs form a conductive network that provides both structural integrity and heating function, with the substrate serving as the mechanical support rather than a polymer binder.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If conventional laminated heater structures with multiple layers and adhesives are used, then the heater can be applied to various surfaces, but the bulky copper leads interfere with the heating performance and the adhesive layers reduce overall reliability

Engineering Contradiction:
Improveapplicability to various surfacesVSAvoidheating performance and durability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent merges the electrical leads directly with the carbon nanotube heating layer and substrate, eliminating separate adhesive layers and intermediate components. The CNT network serves as both the heating element and the electrical conductor, with leads attached directly to the CNT layer or substrate, reducing interface points of failure and improving overall reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs thin-film carbon nanotube networks deposited directly onto flexible or rigid substrates, creating a lightweight, conformable heating element that can be applied to various surfaces without bulky copper leads. The thin-film CNT structure provides flexibility and adaptability while maintaining excellent electrical and thermal performance.

Inventive Principle:
Principle #30Flexible shells and thin films

3Ease of manufacture

If solvents are used in the carbon nanotube dispersion or adhesive layers, then the carbon nanotubes can be properly dispersed and applied, but the solvents degrade the electrical properties of carbon nanotubes and reduce durability

Engineering Contradiction:
Improvedispersion and application processVSAvoiddurability and electrical stability
Core Design Contradiction:
Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The patent changes the processing parameters by using solvent-free or water-based CNT dispersions instead of organic solvents. The CNTs are dispersed in water or applied from the vapor phase, and the dispersion is subsequently dried to leave a pure CNT network. This parameter change eliminates solvent-induced degradation of CNT electrical properties while maintaining effective dispersion and application processes.

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

The solution provides improved adhesion, durability, and resistance to environmental hazards, maintaining low electrical resistance and effective heating performance even under harsh conditions, such as ice formation on aircraft surfaces.

Implementation Method 1

laminated resistive heater... carbon nanotube layer... electrical leads integrated directly onto the substrate, enhancing adhesion and durability while maintaining low electrical resistance

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Implementation Method 2

applied to a grooved substrate with a solventless polyurethane protective coating, enhancing adhesion and durability

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2641451B1Carbon nanotube thin film laminate resistive heater
Publication Date: 2019.03.06 BATTELLE MEMORIAL INST
  • EP2641451B1 patent drawingFigure 1~2
  • EP2641451B1 patent drawingFigure 3
  • EP2641451B1 patent drawingFigure 4

AI summary

Laminated resistive heaters comprising a carbon nanotube layer are described. The invention also includes methods of making laminated resistive heaters and applications using the resistive heaters.