PCB Power Module Liquid Cooling for Switch-Capacitor Heat Control

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Solution Overview

Problem

Electronic power devices in vehicles face temperature-related damage due to environmental and operational heating, and switching losses from inductive loops between capacitors and transistors, leading to increased transistor temperatures.

Innovation Solution

An electronic power device with a substrate carrying controllable switches and capacitive components, featuring a cooling liquid circulation channel that extends to face both components, forming a heat sink and reducing inductive loop effects by limiting the distance between them.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If power components are cooled using conventional air cooling with fins, then the cooling structure is simple, but the heat evacuation efficiency is insufficient and component temperatures exceed operating limits

Engineering Contradiction:
Improvecomponent temperatureVSAvoidoperating reliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent replaces conventional air cooling with liquid cooling by introducing circulation channels that allow coolant flow directly across the power components. The coolant (liquid) circulates through channels positioned to contact or closely approach the capacitors and transistors, providing superior heat transfer efficiency compared to air cooling with fins.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The cooling approach transitions from three-dimensional fin structures extending into air to a planar two-dimensional channel system integrated onto the substrate surface. The channels are arranged in a plane that allows direct thermal contact with multiple power components simultaneously, improving heat evacuation efficiency through enhanced surface area contact.

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

2Loss of energy

If capacitors and transistors are positioned close together to reduce inductive loops, then switching losses are reduced, but heat accumulation increases due to proximity

Engineering Contradiction:
Improveswitching lossVSAvoidtransistor temperature
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The patent merges the cooling function with the structural support function by integrating circulation channels directly onto the substrate that carries both the capacitors and transistors. This unified structure allows close positioning of power components for reduced inductive loops while the integrated channels provide distributed cooling across all components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The channel cross-sectional height varies along the direction perpendicular to the substrate, creating different cooling intensities at different locations. Areas with higher heat generation (such as near transistors) receive enhanced cooling through taller channel sections, while areas with lower heat generation have shorter channel sections, optimizing heat evacuation locally.

Inventive Principle:
Principle #3Local quality

3Temperature

If a cooling channel is positioned to cool both capacitors and transistors, then heat evacuation efficiency is improved, but the device structure becomes more complex

Engineering Contradiction:
Improveheat evacuation efficiencyVSAvoidcooling structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The substrate serves multiple functions: it provides mechanical support for the power components, acts as the base for the cooling channels, and facilitates thermal management. The circulation channels are integrated into the substrate structure itself, allowing a single component to perform both structural and thermal management functions, thereby reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Efficient cooling of power components with a higher heat capacity liquid reduces temperature rises and minimizes inductive loop-induced heating, enhancing the reliability and performance of power devices in vehicles.

Implementation Method 1

the cooling liquid flowing in this section can cool said controllable switch and said capacitive component

Methodology Applied
Scientific EffectHeat transfer: Convection

Implementation Method 2

the capacitive component and the controllable switch are efficiently cooled by said section of the cooling liquid circulation channel forming a heat sink

Methodology Applied
Scientific EffectHeat sink: Heat Sink

Implementation Method 3

These power components can be heated not only by the variation in temperature of the environment external to the vehicle, but also by Joule effect when they are in operation

Methodology Applied
Scientific EffectJoule effect: Joule Heating

Data Source

PatentEP4391756A1Power electronic device
Publication Date: 2024.06.26 VALEO ELECTRIFICATION
  • EP4391756A1 patent drawingFigure 1
  • EP4391756A1 patent drawingFigure 2
  • EP4391756A1 patent drawingFigure 3

AI summary

The invention relates to a power electronic device (2), particularly for vehicles. Said device (2) comprises: - a substrate (4), in particular a printed circuit board, said substrate (4) carrying: o at least one controllable switch (6); and o at least one capacitive component (8). Said device (2) further comprises: - at least one coolant circulation channel (10). When said device (2) is viewed along an axis (A) perpendicular to the substrate (4), the circulation channel (10) extends, at least along a section of said channel (10), opposite both the controllable switch (6) and the capacitive component (8), such that the coolant flowing in this section can cool said controllable switch (6) and said capacitive component (8).