Electric heating device and a method for manufacturing the same
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Solution Overview
Problem
Existing electrical heating devices for motor vehicles face inefficiencies in heat transfer due to contact resistances at phase boundaries, hindering effective decoupling of heat from PTC elements.
Innovation Solution
An electric heating device design where an electrically insulating mass bridges the distance between the heat-emitting element and the PTC element, with the insulating mass being filled in a positioning frame to create a thermally conductive coupling between the heat-emitting and heat-generating elements, using a two-component polymer with high thermal conductivity fillers like aluminum oxide, and a curing process that ensures secure bonding without bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact sheets or insulation layers are used to connect heat-emitting elements to PTC elements, then electrical insulation is provided, but contact resistances at phase boundaries impair heat transfer efficiency
Solution Approach 1:
The patent introduces an electrically insulating mass as an intermediary substance that fills the space between the heat-emitting element and the PTC element. This mass serves dual functions: providing electrical insulation while maintaining thermal conduction. The insulating mass eliminates harmful air gaps and contact resistances at phase boundaries, creating a continuous thermal path without compromising electrical isolation.
Solution Approach 2:
The patent employs composite material structure where the electrically insulating mass combines electrical insulation properties with thermal conduction properties. This composite approach allows the material to simultaneously fulfill both insulation and heat transfer requirements, resolving the contradiction between electrical safety and thermal efficiency.
2Loss of energy
If conventional contact sheets rest on main side surfaces of PTC elements, then electrical connection is established, but heat decoupling is not achieved effectively
Solution Approach 1:
Instead of having the contact sheet rest on the main side surface of the PTC element (conventional approach), the patent inverts the arrangement by having the heat-emitting element contact the insulating mass which then contacts the PTC element. This inversion allows the heat-emitting surface to be at least partially exposed within the frame opening, enabling effective heat extraction while maintaining good thermal coupling through the insulating mass.
Solution Approach 2:
The patent applies local quality by allowing the heat-emitting surface to be partially exposed within the frame opening while other portions are covered by the insulating mass. This localized exposure optimizes heat extraction at critical areas while maintaining thermal coupling through the insulating mass at other areas, achieving effective heat decoupling without compromising heat extraction effectiveness.
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 configuration enhances heat transfer efficiency by minimizing contact resistances and ensuring a strong, thermally conductive bond between the heat-emitting and heat-generating elements, improving the overall performance and reliability of the heating device.
Implementation Method 1
an electrically insulating mass bridges the distance between the heat-emitting element and the PTC element... ensuring a strong, thermally conductive bond between the heat-emitting and heat-generating elements
Implementation Method 2
a curing process that ensures secure bonding without bubble formation
Data Source
Figure 1~3
AI summary
The present invention relates to an electric heating device, in particular for a motor vehicle, with heat-emitting elements (26) and a heat-generating element (30) and heat-emitting elements (26) that are thermally conductively connected to opposite sides thereof, wherein the heat-generating element (30) has a position frame (2) and at least one PTC element (10) which is provided in the position frame (2), has main side surfaces (14) for heat extraction and is connected to contact plates (18) of different polarity, wherein main side surfaces (24) of the position frame (2) are provided with a frame opening (16) leading to the PTC element (10).The present invention further relates to a method for manufacturing an electric heating device in which at least one PTC element (10) is arranged in a positioning frame (2) at a distance from the main side surfaces (24) of the positioning frame (2), an electrically insulating mass (22) with good thermal conductivity is introduced into a frame opening (16) which bridges the distance between one of the main side surfaces (24) and the PTC element (10), a heat-emitting element (26) is placed against the mass (22) and the mass (22) is pressed and cured between the heat-emitting element (26) and the PTC element (10).