PTC Heating Element Thermal Coupling Using Heat-Conductive Compound

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Solution Overview

Problem

Existing electrical heating devices for motor vehicles, which rely on PTC heating elements, face challenges in thermal optimization, leading to inadequate heat dissipation and reduced heat output due to suboptimal contact and decoupling of heat generated by PTC elements.

Innovation Solution

A method involving a U-shaped recess in a heater housing with a heat-conductive compound, such as a silicone-based mass with high thermal conductivity, is used to enhance heat dissipation by filling the gap between the PTC heating element and the recess, ensuring comprehensive contact and efficient heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a PTC heating element is inserted into a U-shaped recess with conventional contact methods, then the device structure is simple, but heat dissipation is insufficient and thermal optimization is inadequate

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidproduction process complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

A wedge element is introduced as an intermediary component between the PTC heating element and the U-shaped recess. This wedge element provides both mechanical clamping force for electrical contact and thermal conduction path for heat dissipation, resolving the contradiction by adding a single component that addresses both electrical and thermal requirements simultaneously

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs composite material strategies by combining different materials with complementary properties - the wedge element uses materials with both electrical insulation and thermal conduction characteristics, while the housing integrates regions with different thermal conductivities to optimize heat dissipation paths without requiring complex multi-component assembly

Inventive Principle:
Principle #40Composite materials

2Reliability

If the PTC element is clamped tightly to ensure good electrical contact, then electrical contact reliability is improved, but thermal decoupling is reduced and heat output decreases

Engineering Contradiction:
Improveelectrical contact reliabilityVSAvoidheat output
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The housing is designed with locally differentiated thermal properties - the U-shaped recess region provides high thermal conductivity for heat dissipation, while the wedge element contact region provides electrical insulation. This spatial differentiation of material properties allows simultaneous optimization of electrical contact and thermal decoupling without compromising either function

Inventive Principle:
Principle #3Local quality

3Use of energy by moving object

If conventional heating methods are used in electric vehicles, then energy consumption is reduced, but process heat generation is insufficient for heating the passenger compartment

Engineering Contradiction:
Improveenergy consumptionVSAvoidprocess heat generation
Core Design Contradiction:
Use of energy by moving objectVSPower

Solution Approach 1:

The patent utilizes the temperature-dependent electrical resistance characteristic of PTC materials. As the PTC element heats up, its resistance increases automatically, regulating the current flow and heat generation. This self-regulating parameter change allows efficient energy conversion to heat while preventing excessive energy consumption, directly addressing the contradiction between energy efficiency and heat generation capability

Inventive Principle:
Principle #35Parameter changes

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 results in improved heat dissipation on all sides of the heating rib, allowing for effective thermal coupling of the PTC heating element with the heater housing, enhancing the heating performance and reliability of the electrical heating device.

Implementation Method 1

a heat-conducting mass is introduced into the U-shaped recess. This heat-conducting compound is preferably an electrically insulating compound

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

PTC elements are also known as PTC thermistor elements because the electrical resistance of the PTC element increases with increasing temperature

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3101365B1Method for producing an electrical heating device
Publication Date: 2019.12.04 EBERSPACHER CATEM GMBH & CO KG
  • EP3101365B1 patent drawingFigure 1~4
  • EP3101365B1 patent drawingFigure 2~5
  • EP3101365B1 patent drawingFigure 6~8

AI summary

The present invention relates to an electric heating device with a heater housing in which a partition separates a circulation chamber (Z) through which a medium to be heated flows from a connection chamber (A), in which electrical connections (6.1) of a PTC heating element (2) with at least one PTC element (4) and conductor tracks (6) on both sides thereof are exposed and which is inserted into a U-shaped recess (18) of a heating fin (14.2) projecting from the partition into the circulation chamber (Z), and a method for its manufacture. For thermal optimization in the method according to the invention, a thermally conductive mass (26) is introduced into the U-shaped recess (18) after the PTC heating element (2) has been inserted.