Capacitive Block Heat Sink for Thermal Dissipation

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Solution Overview

Problem

Capacitors in electrical equipment, such as those in electric or hybrid vehicles, face challenges with heat dissipation due to the limited thermal conductivity of polymerizable resins used for sealing, which can lead to inefficient heat dissipation and potential damage from high-intensity electric currents.

Innovation Solution

A capacitive block design featuring a housing with a capacitive element in direct contact with a heat sink, where the heat sink has higher thermal conductivity than the filling substance, and a free face that forms an external surface devoid of the filling substance, allowing direct heat dissipation to a cooling circuit without air pockets, and utilizing a thermally conductive and dielectric interface layer to prevent short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the capacitive element is surrounded by polymerizable resin for sealing, then watertight protection is achieved, but thermal conductivity is insufficient leading to poor heat dissipation

Engineering Contradiction:
Improvewatertight protectionVSAvoidheat dissipation efficiency
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The sealing system is segmented into two functional zones: the polymerizable resin provides watertight sealing around the capacitive element, while a dedicated heat sink component provides thermal conduction path. This segmentation allows each material to optimize its primary function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A thermally conductive and dielectric interface layer is introduced as an intermediary between the capacitive element and the heat sink. This intermediate layer facilitates efficient thermal transfer while maintaining electrical insulation, resolving the contradiction between sealing requirements and heat dissipation needs.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If thermally conductive material is used for heat dissipation, then heat transfer efficiency improves, but electrical insulation is compromised increasing short circuit risk

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidelectrical insulation
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The heat sink employs composite material structure combining thermally conductive materials with dielectric properties. This composite approach enables simultaneous achievement of high thermal conductivity for efficient heat dissipation and sufficient electrical insulation to prevent short circuits between the capacitive element and heat sink.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The thermally conductive and dielectric interface layer serves as a mediator that reconciles the conflicting requirements of thermal conduction and electrical insulation. This intermediate layer allows heat to flow efficiently from the capacitive element to the heat sink while blocking electrical current paths.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If filling substance completely surrounds the capacitive element, then sealing is maximized, but heat dissipation path is blocked

Engineering Contradiction:
Improvesealing effectivenessVSAvoidheat dissipation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The space around the capacitive element is segmented into a sealing zone filled with polymerizable resin and a thermal conduction zone occupied by the heat sink. This spatial segmentation creates distinct functional regions where sealing and heat dissipation occur simultaneously without interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heat sink extends in the dimensional space to create a dedicated thermal conduction pathway that does not compromise the sealing volume. By utilizing available three-dimensional space efficiently, the heat sink establishes a direct thermal path from the capacitive element to the external environment.

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

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 design enhances heat dissipation efficiency by leveraging the higher thermal conductivity of the heat sink, effectively guiding heat to a cooling circuit and preventing humidity infiltration while ensuring electrical safety through dielectric insulation.

Implementation Method 1

heat dissipation does not take place through the filling substance, but through a heat sink directly in contact with the capacitive element

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the capacity is embedded in a polymerizable resin. Such a resin is cast in a fluid state around the capacity and then polymerized to take a solid state

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Implementation Method 3

The generation of heat by the Joule effect can then become significant with the risk of damaging the capacity

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3621093B1Capacitive block comprising a heat sink
Publication Date: 2022.04.27 VALEO SIEMENS EAUTOMOTIVE FRANCE SAS
  • EP3621093B1 patent drawingFigure 1~2
  • EP3621093B1 patent drawingFigure 3

AI summary

The invention relates to a capacitive block 1, particularly for electrical equipment, comprising a housing 2, a capacitive element housed within the housing 2, a substance 4 filling the space between the housing 2 and the capacitive element so as to seal the capacitive element, and a heat sink 5 against which the capacitive element is in direct contact. In the capacitive block 1, the heat sink 5 is distinct from the filling substance 4, one face of said heat sink 5, referred to as the free face 6, forming an external face of the capacitive block 1 and being devoid of said filling substance 4.