PTC Heating Device with Insulating Elements to Prevent Short Circuits
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Solution Overview
Problem
Existing electrical heating devices with PTC elements for motor vehicles are prone to short circuits due to deformations in contact plates, which compromises their reliability and effectiveness.
Innovation Solution
Incorporating electrically insulating elements between contact plates, which are designed to match or exceed the dimensions of the PTC elements, and using a combination of adhesive and structural features such as roughened surfaces, projections, and elastic connections to enhance stability and prevent short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact plates are used for electrical contacting without additional insulating elements, then the device structure is simpler, but short circuits occur due to deformations in contact plates
Solution Approach 1:
Electrically insulating elements are introduced as intermediary components between the contact plates and PTC heating elements. These insulating elements prevent direct electrical contact between opposing contact plates, thereby eliminating short circuit risks while maintaining the structural framework of the heating device.
Solution Approach 2:
The contact plate assembly is segmented by inserting insulating elements at specific intervals between the contact plates. This segmentation divides the continuous conductive path into isolated sections, preventing deformation-induced short circuits while preserving the overall structural integrity and heating functionality.
2Reliability
If PTC elements are arranged between contact plates without insulating elements, then the heat transfer path is more direct, but deformations cause short circuits
Solution Approach 1:
Insulating elements serve as mediators positioned between the conductive contact plates and the PTC heating elements. They provide electrical isolation without interfering with the thermal coupling, as heat transfers through conduction and convection while electrical current is blocked by the insulating material.
3Strength
If adhesive connections are used to join contact plates and PTC elements, then the assembly is simpler, but the connection strength is insufficient
Solution Approach 1:
The connection system uses a composite approach combining adhesive materials with mechanically interlocking features. The insulating elements incorporate protrusions that fit into corresponding recesses in the contact plates, creating a hybrid connection that leverages both chemical bonding (adhesive) and mechanical engagement for enhanced strength.
Solution Approach 2:
The insulating elements feature curved or rounded protrusions that complement the recesses in the contact plates. This geometric design allows for tolerant assembly while maintaining strong mechanical interlocking, as the curved surfaces distribute contact stresses and facilitate easier insertion compared to sharp-edged features.
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 solution significantly reduces the risk of short circuits by creating a stronger, more stable connection between contact plates and PTC elements, ensuring reliable heat transfer and operation.
Implementation Method 1
PTC elements or plastic PTC elements, provided, and at least one electrically insulating element is arranged between two contact plates
Implementation Method 2
The insulating element is preferably glued directly between the contact plates
Data Source
Figure 1~2
Figure 3
Figure 4a~4f
AI summary
The device (1) has a heat transfer section for transferring heat to a fluid that flows through the device, where a set of positive temperature coefficient (PTC)-units (3) arranged between contact plates (5) is provided in the heat transfer section. An insulating unit (4) is arranged between two contact plates next to the PTC-unit, and is connected with one of the contact plates in a positive and non-positive manner.