Self-Regulating Heating Laminate With Low-Voltage PTC Sheet Structure
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Solution Overview
Problem
Existing flat sheet heaters often require multiple layers and materials, are not sustainable, and pose safety risks due to high voltage requirements, limiting their use in close contact with humans or animals.
Innovation Solution
A self-regulating flat sheet heater design is created through coextrusion or colamination, using a semiconductive composition with a positive temperature coefficient (PTC) comprising polyolefin and a conductive filler, eliminating the need for regulating electronics and allowing for rapid heating with lower voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple layers and materials are used in flat sheet heaters, then heating performance is improved, but device complexity and material consumption increase
Solution Approach 1:
The patent combines multiple functional layers (heating element, insulation, protection) into a single integrated flat sheet structure with uniform thickness. The semiconductive polymer material inherently provides both heating and insulation functions, eliminating the need for separate layers and reducing overall device complexity while maintaining heating performance.
Solution Approach 2:
The semiconductive polymer composition serves multiple functions simultaneously: it acts as the heating element, thermal insulation layer, and protective coating. This multi-functionality reduces the number of separate materials and layers needed, simplifying the overall device structure while achieving effective heating.
2Power
If high voltage is used in flat sheet heaters, then heating power is improved, but safety risks increase for close contact applications
Solution Approach 1:
The patent changes the electrical parameters of the heating system by using low-voltage direct current (DC) power supply instead of high voltage. The semiconductive polymer material enables effective heating at low voltages due to its unique electrical properties, thereby eliminating safety risks associated with high voltage while maintaining adequate heating power for close contact applications.
3Power
If traditional heating elements are used, then heating effectiveness is improved, but sustainability and material recyclability worsen
Solution Approach 1:
The patent employs a semiconductive polymer material that can be recycled and reused. The material can be processed through extrusion or lamination techniques to create new heating elements, enabling recovery and reuse of the material rather than disposal. This improves sustainability while maintaining heating effectiveness through the inherent properties of the semiconductive polymer.
4Power
If complex multi-layer structures are used, then heating performance is improved, but manufacturing cost and production complexity increase
Solution Approach 1:
The patent segments the manufacturing process into simple, scalable steps such as extrusion or lamination of the semiconductive polymer material. This allows for continuous production of flat sheet heaters with consistent heating performance while minimizing manufacturing complexity and cost through process standardization and automation potential.
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 design achieves rapid heating, reduces material consumption, enhances sustainability, and ensures safe operation with lower voltages, suitable for various applications including heated clothing and car seats.
Implementation Method 1
the heating element has a positive temperature coefficient of resistance. Thus, as the temperature of the heating element increases, the resistance of the material electrically connected between the conductors increases, thereby reducing power output
Implementation Method 2
Self-regulation utilises a conversion from electrical to thermal energy by allowing a current to pass through a semiconductive medium with Positive temperature coefficient (PTC) characteristics
Data Source
AI summary
A flat sheet electrical heater, preferably obtainable by coextrusion or colamination, comprising: a plurality of elongate conductors, preferably evenly spaced apart from and preferably substantially parallel to each other, said conductors being at least partially embedded within and in contact with an electrically semiconductive composition with a positive temperature coefficient (PTC) comprising a polyethylene, polypropylene or a mixture thereof and a conductive filler, wherein said electrically semiconductive composition preferably is comprised in an extruded film having a machine direction and said elongate conductors are preferably parallel with the machine direction of the extruded film comprising the semiconductive composition: wherein the semiconductive composition has an electrical conductivity σ from 2 to 50 S/m, measured at 40° C. in accordance with the “Conductivity method” as described under “Determination methods”, wherein 20° C.≤TEq≤50° C. and TEq is defined as the temperature where dσ/dT is at its minimum.