CNT Yarn Heater Structure for Low-Resistance Conductive Heating
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Solution Overview
Problem
Carbon nanotube yarns incorporated into films for heating elements suffer from increased electrical resistivity due to air voids and random orientation of carbon nanotubes, limiting their suitability for aerospace applications requiring low-resistance heating.
Innovation Solution
Directly incorporating carbon nanotube yarn into heating elements as strands or woven structures without films, allowing for alignment of nanotubes in the direction of current flow to reduce electrical resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carbon nanotube yarn is incorporated into a substrate film for heating elements, then the structural support and flexibility are improved, but the electrical conductivity deteriorates due to air voids and random orientation of carbon nanotubes
Solution Approach 1:
The patent removes the substrate film from the heating element structure, extracting the problematic component that caused air voids and random nanotube orientation. The CNT yarn is now directly incorporated into the heating element without being embedded in a film, eliminating the source of conductivity deterioration while maintaining structural integrity through the yarn's inherent properties
Solution Approach 2:
The patent changes the structural parameter from 'CNT yarn embedded in substrate film' to 'CNT yarn directly in heating element'. This parameter change eliminates the interface between yarn and film that created air voids, and allows for controlled alignment of nanotubes in the direction of current flow, thereby improving electrical conductivity
2Strength
If carbon nanotubes are spun into long fibers and plied together to form yarn, then the mechanical properties and flexibility are improved, but the electrical resistivity increases when incorporated into films
Solution Approach 1:
The patent applies preliminary alignment of carbon nanotubes in the direction of current flow before incorporating the yarn into the heating element. This preliminary action ensures that the nanotubes are optimally oriented for electrical conductivity before the final assembly, preventing the resistivity increase that occurs when yarn is randomly embedded in films
Solution Approach 2:
The patent uses the CNT yarn itself as the primary conductive material in a direct composite structure with the heating element, rather than using it as an embedded component within a film composite. This approach maintains the beneficial mechanical properties of the plied yarn while achieving the desired electrical conductivity through direct integration
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 direct incorporation of carbon nanotube yarns in heating elements eliminates air voids and enables better conductivity, providing effective low-resistance heating suitable for aerospace applications.
Implementation Method 1
Carbon nanotubes are spun into long fibers and can be plied together or stretched to provide the desired length and mechanical properties
Implementation Method 2
some CNTs can have high thermal and electrical conductivity, making them suitable for replacing metal heating elements
Data Source
Figure 1A~1D
Figure 2~3B
AI summary
A heating element (10) includes a bottom layer (12), a web (18A) consisting of a carbon nanotube (CNT) yarn (14) wherein the web is affixed to a first side of the bottom layer (12), and an encapsulating layer positioned on the web (18A) and the first side of the bottom layer (12). A method for making a heating element (10) includes providing a bottom layer (12), inserting a plurality of pegs (20) into the bottom layer (12) such that a portion of each peg (20) protrudes from the bottom layer (12), weaving a CNT yarn (14) around the protruding portions of the plurality of pegs to form a CNT web, affixing the CNT web (18A) to the bottom layer, and encapsulating the CNT web and the bottom layer to form the heating element.