Perforated CNT Sheet Resistivity Tuning for Ice Protection

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Solution Overview

Problem

Commercially available carbon nanotube materials do not offer adjustable electrical resistivities suitable for ice protection applications, limiting their use in technologies where tailored heating is required.

Innovation Solution

Creating a heating element with perforated carbon nanotube layers, where the perforation density and distribution alter the electrical resistivity, allowing for customized heating and ice protection by varying the resistivity of the CNT layers through the use of perforated and non-perforated regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If commercially available CNT materials are used, then ease of manufacture is improved, but adaptability to different ice protection applications deteriorates due to fixed electrical resistivity

Engineering Contradiction:
Improveease of manufactureVSAvoidadaptability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by modifying the electrical resistivity of CNT materials through controlled perforation. By varying the perforation density (number of holes per unit area) in different regions of the CNT sheet, the electrical resistivity is tuned to match specific ice protection application requirements. This allows a single base material to adapt to multiple applications with different heating requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements local quality by creating different perforation densities in different regions of the CNT sheet. Areas with higher perforation density have higher electrical resistivity and generate more heat, while areas with lower perforation density have lower resistivity and generate less heat. This spatial variation in properties enables tailored heating patterns for different ice protection zones on aircraft surfaces.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If perforated CNT layers are used to adjust resistivity, then adaptability to different applications is improved, but device complexity increases due to multiple perforated and non-perforated regions

Engineering Contradiction:
ImproveadaptabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the CNT sheet into distinct regions with different perforation densities. The sheet is segmented into first perforated regions with higher resistivity and second perforated regions with lower resistivity. This segmentation allows each region to be optimized for specific heating requirements while maintaining overall system functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamics by creating an adjustable and reconfigurable heating system. The perforation pattern can be designed with varying densities to dynamically tune the electrical resistivity and heat generation characteristics. This dynamic adjustability allows the same CNT sheet to serve different applications by modifying the perforation configuration rather than requiring multiple specialized materials.

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

Enables tailored electrical resistivity in carbon nanotube heating elements for specific applications, enhancing their suitability for aerospace, aviation, and wind turbine technologies by providing selective heating and ice protection.

Implementation Method 1

When current is passed through the CNT layer(s), the CNTs within the layer(s) emit heat energy (i.e. Joule heating)

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

CNT particles are attached to one another via Van der Waals forces

Methodology Applied
Scientific EffectVan der Waals forces: Van der Waals Force

Data Source

PatentEP3334240B1Adjusting CNT resistance using perforated CNT sheets
Publication Date: 2021.08.18 GOODRICH CORP
  • EP3334240B1 patent drawingFigure 1~2
  • EP3334240B1 patent drawingFigure 3~4

AI summary

The invention provides a heating element comprising a perforated CNT sheet or layer. One example of a heating element includes a first carbon nanotube (CNT) layer and a second CNT layer. At least a portion of the first CNT layer overlaps at least a portion of the second CNT layer, and the first CNT layer includes a first perforated region having a plurality of perforations. Another heating element includes a CNT sheet with a first perforated region having a plurality of perforations and a first perforation density and a second perforated region having a plurality of perforations and a second perforation density different from the first perforation density. A method of forming a heating element includes perforating a first CNT layer so that it includes a perforated region and stacking the first CNT layer with a second CNT layer such that at least a portion of the first CNT layer overlaps at least a portion of the second CNT layer.