PTC heating device and method for producing same

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Solution Overview

Problem

Current PTC heating devices for motor vehicles face challenges in ensuring electrical safety and efficient manufacturing, particularly when operated at higher voltages and requiring precise insulation and creepage distances, while also needing to reduce production time and material usage.

Innovation Solution

A PTC heating device with a ceramic PTC element and metallization contact surfaces, using a sparse frame with an electrically insulating mass between the frame and heating cell, and discrete dosages of hardened silicone mass to secure the heating cell, creating a circumferential edge for electrical safety and minimizing material usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the heating cell is completely surrounded with electrically insulating mass, then electrical safety is improved, but material usage and production time increase

Engineering Contradiction:
Improveelectrical safetyVSAvoidinsulating mass
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies electrically insulating mass selectively only in critical areas where electrical insulation is required, rather than completely surrounding the heating cell. The insulating mass is positioned specifically between the frame and heating cell at locations where electrical isolation is necessary, reducing overall material usage while maintaining electrical safety.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent divides the insulation approach into discrete segments or dosages of insulating mass placed at specific locations, rather than using a continuous complete enclosure. This segmented approach allows insulation to be applied only where needed, reducing total material quantity while maintaining electrical safety.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the compound is heated to accelerate curing, then production time is reduced, but energy consumption increases

Engineering Contradiction:
Improvecuring timeVSAvoidenergy for heating
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent utilizes the heat generated by the PTC element itself during its normal operation to cure the electrically insulating mass, rather than requiring external heating equipment. The PTC element's self-heating property is leveraged to perform the curing function, eliminating the need for separate energy-consuming heating processes.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The PTC element serves dual functions: it provides the heating function for the device's primary purpose and simultaneously acts as a heat source for curing the insulating mass during manufacturing. This multi-functionality reduces the need for additional dedicated curing equipment and energy input.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If air gaps are maintained in the frame, then manufacturing simplicity is improved, but electrical insulation performance deteriorates

Engineering Contradiction:
Improveframe constructionVSAvoidelectrical insulation
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces electrically insulating mass as an intermediary material between the frame and heating cell. This intermediary fills the gaps and spaces in the frame structure, providing the necessary electrical insulation without requiring a completely solid or complex frame design. The insulating mass acts as a mediator that maintains both manufacturing simplicity and insulation performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enhances electrical safety by preventing direct contact between the insulating mass and metallization, reduces material usage, and shortens the curing time, ensuring reliable and economic production of PTC heating devices for motor vehicles.

Implementation Method 1

a heating cell (24) comprising at least one PTC element (14) made of a ceramic material

Methodology Applied
Scientific EffectPTC (Positive Temperature Coefficient) effect: Electrical Resistance

Implementation Method 2

Contact elements (16.1; 16.2) rest in an electrically conductive manner against the regularly opposite contact surfaces (40) formed by the metallization (38), which serve to supply the power current to the PTC element (14)

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

an electrically insulating mass (46) is located between the inner circumference of the frame (22) and the outer circumference of the heating cell (24)

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 4

This is usually created by sputtering an electrically conductive material onto the ceramic surface of the PTC element (14)

Methodology Applied
Scientific EffectSputtering: Sputtering

Implementation Method 5

The mass is cured and therefore dimensionally stable. The mass serves to secure the heating cell (24) within the frame (22)

Methodology Applied
Scientific EffectCuring:

Data Source

PatentEP4351273A1PTC heating device and method for producing same
Publication Date: 2024.04.10 EBERSPACHER CATEM GMBH & CO KG
  • EP4351273A1 patent drawingFigure 1
  • EP4351273A1 patent drawingFigure 2~5
  • EP4351273A1 patent drawing

AI summary

The present invention relates to a PTC heating device (12) and a method for its manufacture with a frame (22) in which a heating cell (24) comprising at least one PTC element (14) made of a ceramic material and contact elements (16.1; 16.2) of different polarity are accommodated, wherein the PTC element (14) has contact surfaces (40) formed by a metallization (38) and the contact elements (16.1; 16.2) are each electrically contacted with one of the contact surfaces (40).An economically producible and electrically safe PTC heating device (14) according to the present invention has an electrically insulating cured compound (46) arranged between the outer circumference of the heating cell (24) and the inner circumference of the frame (22), which secures the heating cell (24) in the frame (22), wherein a rim (44) formed by the ceramic material of the PTC element (14) is provided between the compound (46) and the contact surface (40). In the method according to the invention, after the PTC element (14) is inserted into the frame (22), an electrically insulating compound (46) is applied at the level of the rim (44), by which the PTC element (14) is secured after the frame (22) has cured.