Polymer PTC Element on Layered Support for Rapid Thermal Detection
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Solution Overview
Problem
Ceramic PTC elements fail to rapidly interrupt current when the substrate temperature exceeds a critical value due to insufficient increase in resistance value over time, leading to potential overheating in electrical apparatuses.
Innovation Solution
A PTC device comprising a polymer PTC element supported on a layered heat transfer medium, molded in resin to enhance thermal conductivity and protect against environmental factors, allowing for rapid temperature detection and intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceramic PTC element is used to detect substrate temperature, then the substrate can be prevented from reaching extraordinary high temperature, but the resistance value does not sharply increase in a short time causing delayed current interruption
Solution Approach 1:
The patent changes the material parameter of the PTC element from ceramic to polymer, which fundamentally alters the temperature-resistance characteristic. The polymer PTC element exhibits a sharp resistance increase at the critical temperature point, enabling rapid current interruption while maintaining reliable temperature detection functionality.
Solution Approach 2:
The invention uses a polymer PTC element that replicates the temperature detection function of ceramic PTC elements but with improved temporal characteristics. The polymer material copies the essential PTC effect while achieving faster response due to its material properties.
2Speed
If the PTC element is exposed to the environment, then it can directly detect temperature, but it is adversely affected by moisture, oxygen and other environmental factors
Solution Approach 1:
The patent introduces a resin coating as an intermediary layer between the polymer PTC element and the external environment. This coating acts as a barrier that prevents direct contact with moisture and oxygen while allowing thermal energy to pass through, thus protecting the element without isolating it from temperature changes.
Solution Approach 2:
The invention creates a composite structure by coating the polymer PTC element with resin material. This composite provides both the thermal sensitivity of the polymer and the environmental protection of the resin, combining the beneficial properties of different materials.
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 polymer PTC element with a layered support structure effectively detects and responds to temperature increases, providing a sharper resistance increase and faster intervention to prevent overheating, outperforming ceramic PTC elements in terms of sensitivity and response time.
Implementation Method 1
the layered support functions as a heat transfer medium... heat is rapidly conducted from the object to the exposed surface of the layered support
Implementation Method 2
a polymer PTC element having a property of rapidly increasing in its resistance value... when the temperature of the PTC element exceeds a given critical value
Implementation Method 3
the molded resin has a barrier function against moisture, oxygen and the like
Data Source
AI summary
There is provided a PTC device having a sufficient function to detect the possibility of the substrate reaching an extraordinary high temperature more rapidly, and prevent the substrate from reaching such an extraordinary high temperature beforehand. The PTC device 10 includes a layered support 14 that functions as a heat transfer medium and a polymer PTC element 12 disposed thereon wherein the polymer PTC element is disposed on one surface 15 of the layered support (in a thermally connected condition) and the polymer PTC element and the layered support are molded in a resin such that the other surface 15′ of the layered support is exposed.