Variable Thickness Heating Conductor Track for Homogeneous Temperature

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Solution Overview

Problem

Existing electrical heating devices for mobile applications, particularly in electric vehicles, face challenges in achieving a homogeneous temperature profile while avoiding local hot spots that can reduce service life and require additional space or complex designs.

Innovation Solution

The electrical heating device features a heating conductor track with a curved section where the thickness is reduced in the inner curve compared to the outer curve, minimizing local heating and ensuring a more even current distribution, achieved through structured material removal, such as laser processing, to prevent hot spots and optimize space usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the heating conductor track is made with uniform thickness, then the manufacturing process is simple, but local hot spots form in curved sections reducing service life

Engineering Contradiction:
Improveservice lifeVSAvoidheating conductor track structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The heating conductor track is designed with variable thickness: thicker in outer curve regions and thinner in inner curve regions. This local variation in geometry compensates for the shorter current path in inner curves, equalizing electrical resistance across different sections and eliminating hot spots that would reduce service life.

Inventive Principle:
Principle #3Local quality

2Reliability

If additional insulation areas are provided in curved sections, then current distribution is improved, but additional space is required in the main plane

Engineering Contradiction:
Improvecurrent distributionVSAvoidspace in main plane
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

Instead of adding insulation areas in the planar dimension (which would increase the footprint), the invention modifies the thickness dimension of the heating conductor track itself. By varying the thickness in the Z-direction, the patent achieves improved current distribution without requiring additional space in the X-Y plane, thus optimizing space utilization.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If the heating conductor track thickness is reduced in inner curve regions, then current distribution becomes more homogeneous, but manufacturing precision requirements increase

Engineering Contradiction:
Improvetemperature profileVSAvoidthickness control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention changes the geometric parameter of the heating conductor track from uniform thickness to variable thickness. Specifically, the thickness is reduced in inner curve regions compared to outer curve regions. This parameter change creates more homogeneous current distribution and temperature profile, accepting that manufacturing precision requirements increase but delivering superior thermal performance.

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 a significantly more homogeneous temperature profile, reduced risk of premature failure, increased heating power per unit area, and efficient use of space, while being cost-effective and simple to implement.

Implementation Method 1

a heating conductor layer (4) which is formed on the substrate (2) and has at least one heating conductor (5) extending in a main plane on the substrate

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3305017B1Electrical heating means for mobile application
Publication Date: 2021.07.14 WEBASTO AG
  • EP3305017B1 patent drawingFigure 1~2
  • EP3305017B1 patent drawingFigure 3~4
  • EP3305017B1 patent drawingFigure 5~6

AI summary

The invention relates to an electrical heating device (1) for mobile applications, comprising a substrate (2) and a heat-conductor layer (4) formed on the substrate (2). The heat-conductor layer (4) has at least one heat-conductor path (5) that extends in a main plane on the substrate (2). The heat-conductor path (5) is structured in such a way that a plurality of path sections (6) are formed, said path sections running next to one another and being separated from one another by insulating interruptions (7). The heat-conductor path has at least one curved section (8) at which the heat-conductor path (5) is diverted in the main plane, and the heat-conductor path (5) is formed in the curved section (8) in such a way that, in the region of the inner curve (10a), it has a smaller thickness in the direction perpendicular to the main plane than in the region of the outer curve (10b).