Divided Heatsink Isolates Electrical Potentials in Power Modules

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Solution Overview

Problem

Existing power modules in electric vehicles and hybrid vehicles face challenges in efficiently cooling power components while preventing electrical corrosion and ground loops, as conventional heat sinks do not adequately isolate different electrical potentials and can lead to corrosion due to mass flow.

Innovation Solution

A heat sink design with multiple parts connected via an electrical insulator allows fluid flow for cooling while maintaining electrical insulation, preventing corrosion and ground loops by using aluminum or copper parts with an insulating layer, and employing a fluid-tight connection with a small passage opening for limited electrical contact resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional heat sinks are used to cool power components, then cooling efficiency is improved, but electrical corrosion and ground loops occur due to lack of isolation between different electrical potentials

Engineering Contradiction:
Improvecooling efficiencyVSAvoidelectrical corrosion
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The heat sink is divided into multiple electrically insulated parts (first heat sink part and second heat sink part) that are thermally connected but electrically isolated from each other. This segmentation allows each part to be connected to different electrical potentials (e.g., inverter ground and motor ground) without causing electrical corrosion or ground loops, while maintaining effective cooling through the thermally conductive connection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An electrical insulator is introduced as an intermediary element between the first and second heat sink parts. This insulator prevents electrical current flow between the parts while allowing thermal energy to be transferred, thus eliminating electrical corrosion risks while preserving cooling efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If aluminum heat sink parts are used for thermal conduction, then cooling performance is improved, but mass flow causes electrocorrosion through electrolysis

Engineering Contradiction:
Improvethermal conductivityVSAvoidelectrocorrosion
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The heat sink is segmented into electrically isolated parts, which prevents mass flow (electrocorrosion) from occurring within the heat sink structure itself. Each part can be made of aluminum for optimal thermal conductivity, but the electrical insulation between parts eliminates the electrolysis process that would otherwise cause corrosion.

Inventive Principle:
Principle #1Segmentation

3Temperature

If power components are thermally connected to a common heat sink, then cooling efficiency is improved, but ground loops cause electrocorrosion

Engineering Contradiction:
Improvecooling efficiencyVSAvoidground loops
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The common heat sink is segmented into electrically insulated parts that can be connected to different ground potentials. The first heat sink part connects to the inverter ground while the second heat sink part connects to the motor ground, eliminating ground loops while maintaining thermal connection for efficient cooling of both power components.

Inventive Principle:
Principle #1Segmentation

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 effectively isolates electrical potentials, prevents corrosion, and maintains high thermal conductivity, ensuring efficient cooling and reliable operation of power components in electric vehicles and hybrid vehicles.

Implementation Method 1

the parts are electrically insulated from one another by means of an electrical insulator such that a fluid flow cooling both parts can flow through the parts, wherein the parts are electrically insulated from one another such that the electrical potentials of the power components are separated from one another within the heat sink

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

The heat sink comprises at least or only two parts, in particular one part and another part, which each have a cavity for conducting a fluid flow

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

designed for fluid conduction... a fluid flow cooling both parts can flow through the parts

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

a fluid flow cooling both parts can flow through the parts

Methodology Applied
Scientific EffectHeat absorption: Absorption (physical)

Data Source

PatentEP4252497B1Power module with an insulated, divided heatsink, and vehicle with a power module
Publication Date: 2024.07.24 ROBERT BOSCH GMBH
  • EP4252497B1 patent drawingFigure 1
  • EP4252497B1 patent drawingFigure 2

AI summary

The invention relates to a power module, in particular a drive module. The power module has a heatsink, which is designed for conducting fluid and acts in particular as a cooling element, and at least two power components, which are different from one another. The power components are each connected thermally conductively, and in some cases also electrically conductively, to the heatsink, in particular to a part of the heatsink. According to the invention, the power components are each designed to carry electric potentials, in particular earth potentials, which are different from one another. The heatsink comprises at least two parts or just two parts, in particular one part and a further part which each have a cavity for conducting a stream of fluid and which are connected to one another by means of an electrical insulator in such a way that each of the parts can be flowed through by a stream of fluid that cools both of the parts, wherein the parts are electrically insulated from one another in such a way that the electric potentials of the power components are separated from one another within the heatsink.