PTC heating element and method for its production
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Solution Overview
Problem
PTC heating elements for high-voltage applications in electric vehicles face challenges in achieving high heat extraction and efficient heat dissipation while maintaining cost-effective production and scalability.
Innovation Solution
The PTC heating element design features electrical contact via end faces, eliminating the need for conductor tracks on main side surfaces, allowing for direct heat dissipation through an insulating layer and improved heat density, with conductor tracks formed by metal strips and contact springs that are easily producible and securely connected using insulating bridge elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conductor tracks are placed on the main side surfaces of the PTC element, then electrical contact is established, but heat extraction is reduced due to the insulating layer blocking heat dissipation
Solution Approach 1:
The patent moves the electrical contact from the main side surfaces (2D plane) to the end faces (3D terminal surfaces) of the PTC element. This dimensional shift allows the main side surfaces to be fully dedicated to heat dissipation without conductor tracks, while electrical contact is maintained through the end faces where the insulating layer extends to form contact surfaces.
Solution Approach 2:
The insulating layer serves as a dual-function intermediary: it provides electrical insulation between conductor tracks and the PTC element, and simultaneously acts as a heat transfer medium. By extending the insulating layer to the end faces and providing conductor tracks on these faces, the patent enables thermal contact through the insulating material while maintaining electrical isolation.
2Temperature
If conductor tracks are placed on the main side surfaces, then electrical contact is made, but the PTC element becomes thicker and heat density decreases
Solution Approach 1:
The patent relocates conductor tracks from the main side surfaces to the end faces of the PTC element. This repositioning eliminates the need for thick insulating layers on the main surfaces, reducing overall element thickness and increasing heat density, while electrical contact is maintained through the end face configuration.
3Loss of energy
If insulating layer is placed on conductor tracks, then electrical insulation is provided, but heat transfer efficiency is reduced
Solution Approach 1:
The insulating layer is repositioned to extend to the end faces of the PTC element, where it serves as both an electrical insulator and a thermal contact surface. Conductor tracks are placed on these end faces, allowing heat to transfer efficiently through the insulating material to the medium being heated, while electrical insulation is maintained between the tracks and the PTC element body.
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
This design enhances heat extraction and efficiency by allowing direct heat transfer from the PTC element's main side surfaces, improving heat density and scalability, while maintaining reliable and cost-effective production.
Implementation Method 1
This contact spring bears elastically against an end face of the PTC element
Implementation Method 2
The heat is usually introduced directly into an insulating layer and transferred via this to its outer surface by means of heat conduction
Implementation Method 3
The outer surface of the insulating sheet is usually exposed in the flow of fluid to be heated
Data Source
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AI summary
The present invention relates to a PTC heating element with a PTC element (12) which is electrically conductively contacted with electrical conductor tracks (2, 32) with different polarities. In order to improve heat decoupling and efficiency, the present invention proposes forming at least one of the conductor tracks by a metal strip (2, 32) which forms a contact spring (8) which presses elastically against an end face (34) of the PTC element (12 ) is present. In the manufacturing method according to the invention, a PTC element (12) is first arranged between two conductor tracks, of which at least one conductor track is formed by a metal strip (2, 32), this metal strip (2, 32) forming a contact spring (8). The conductor tracks are then brought closer together until the contact spring 8 is prestressed against an end face (34) of the PTC element (12). Then the conductor tracks (2, 32) are fixed to secure the electrical contact thus produced.