Thermally Conductive Covered Component for Crack-Resistant Heat Dissipation

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Solution Overview

Problem

Existing thermally conductive encapsulants used in power electronics and electrical machines often detach or crack during thermal cycling due to mismatched thermal expansion coefficients, impairing heat dissipation.

Innovation Solution

A thermally conductive encased component comprising a coil pot with multiple openings filled with a thermally conductive encapsulating compound containing at least 25% ceramic particles, which maintains contact with the element and ensures effective heat transfer through thermal cycling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a thermally conductive encapsulant is used to encapsulate electrically conductive elements, then heat dissipation is improved, but the encapsulant detaches or cracks during thermal cycling due to mismatched thermal expansion coefficients

Engineering Contradiction:
Improveheat dissipationVSAvoidencapsulant integrity during thermal cycling
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent modifies the physical-chemical parameters of the encapsulating compound by incorporating ceramic particles (aluminum oxide, aluminum nitride, boron nitride, silicon nitride) with specific thermal expansion properties. This changes the overall thermal expansion coefficient of the encapsulant to better match that of the copper elements, preventing detachment and cracking during thermal cycling while maintaining thermal conductivity of at least 1 W/mK

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite encapsulating material consisting of a polymer or cement matrix combined with ceramic particles. This composite structure combines the thermal conductivity benefits of ceramics with the flexibility and adhesion properties of the matrix material, achieving both improved heat dissipation and maintained structural integrity during thermal expansion/contraction cycles

Inventive Principle:
Principle #40Composite materials

2Loss of energy

If the encapsulating compound contains high ceramic particle content to ensure thermal conductivity, then heat transfer is improved, but the compound may become more brittle and prone to cracking

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidcompound brittleness
Core Design Contradiction:
Loss of energyVSStrength

Solution Approach 1:

The patent formulates a composite where ceramic particles (providing thermal conductivity) are embedded in a polymer or cement matrix (providing flexibility and crack resistance). This composite structure allows the material to maintain both high thermal conductivity (≥1 W/mK) and adequate mechanical strength to prevent brittleness-induced cracking during thermal cycling

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the particle size distribution and concentration of ceramic particles within the matrix, ensuring adequate spacing between particles to prevent stress concentration. This parameter optimization allows high ceramic content for thermal conductivity while maintaining matrix continuity for structural integrity

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

The solution prevents detachment and cracking of the encapsulant, ensuring reliable heat transfer and improved heat dissipation performance during thermal cycling.

Implementation Method 1

Heat can then be transferred from a heat source via the encapsulating compound to the element for heat dissipation

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

These encapsulants typically have a different coefficient of thermal expansion than the heated elements they encapsulate, which may be made of copper, for example. This can lead to detachment of the encapsulant from the electrically conductive elements or to cracks during thermal cycling

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3987556B1Covered component and method for producing same
Publication Date: 2025.06.04 ROBERT BOSCH GMBH
  • EP3987556B1 patent drawingFigure 1~2
  • EP3987556B1 patent drawingFigure 3~4
  • EP3987556B1 patent drawingFigure 5

AI summary

The invention relates to a covered component (10) having a thermally conductive element (20) and a thermally conductive covering material (30) which is filled into an inner region of the element (20). The element (20) has multiple openings (21) which connect the inner region to an outer region of the element (20), wherein the covering material (30) fills the openings (21). The invention additionally relates to a method for producing the covered component (10) in that an inner region of a thermally conductive element (20) which has multiple openings (21) is filled with a covering material (30) such that the material enters the openings (21).