Millichannel Cooling Device for Power Module Thermal Management

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Solution Overview

Problem

Conventional power module cooling devices face limitations due to large thermal gradients, high-pressure drops, and high thermal resistance, which restrict the operational levels of power modules, especially when using microchannels that compromise mechanical and electrical properties.

Innovation Solution

A cooling device with a heat sink plate and base plate configuration that incorporates millichannels, allowing for a larger flow area with constant flow velocity and low pressure drop, minimizing thermal gradients and reducing thermal resistance by directing the cooling medium through inlet and outlet manifold channels with a tapered cross-section and orthogonal millichannel arrangement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If microchannels are used in conventional cooling devices, then cooling efficiency is improved, but mechanical and electrical properties are compromised

Engineering Contradiction:
Improvecooling efficiencyVSAvoidmechanical and electrical properties
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent transitions from microchannels to millichannels, changing the dimensional parameters of the cooling channels. This parameter change allows for larger cross-sectional areas that improve cooling efficiency while maintaining structural integrity and not compromising mechanical and electrical properties of the power module

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a multi-layered substrate structure with millichannels distributed across different layers (first substrate layer, second substrate layer, and intermediate layer). This dimensional distribution allows the cooling system to achieve better thermal management without concentrating stress or damage in a single location, thereby preserving mechanical and electrical reliability

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

2Temperature

If conventional cooling devices with large thermal gradients are used, then heat removal is achieved, but thermal resistance increases and limits operation levels

Engineering Contradiction:
Improveheat removal capabilityVSAvoidoperation levels
Core Design Contradiction:
TemperatureVSPower

Solution Approach 1:

The cooling system is segmented into multiple independent millichannel layers distributed across different substrate layers. This segmentation creates multiple parallel heat removal paths, reducing thermal gradients within each channel while collectively achieving superior heat removal capability. The segmented structure lowers overall thermal resistance and enables higher operation levels

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The millichannels are nested within the multi-layered substrate structure, with channels in the first substrate layer, second substrate layer, and intermediate layer working together in a nested configuration. This nested arrangement optimizes heat flow paths and reduces thermal resistance, enabling the power module to operate at higher power levels

Inventive Principle:
Principle #7Nested doll (Nesting)

3Temperature

If cooling channels extend through the electrically isolating layer, then heat exchange is improved, but mechanical and electrical properties are reduced

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidmechanical and electrical properties
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The cooling channels are segmented and confined to specific substrate layers (first and second substrate layers) rather than extending continuously through the electrically isolating layer. This segmentation maintains heat exchange efficiency within each layer while preserving the integrity and functionality of the electrically isolating layer, thereby maintaining mechanical and electrical properties

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 configuration enables higher power levels and lower thermal resistance, allowing the power module to operate effectively at increased temperatures with improved mechanical and electrical properties.

Implementation Method 1

heat generated in the electronic power devices is exchanged between the substrate resp. the electronic power devices and the base plate

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

A cooling medium such as water is passed through the tubes to cool the power module

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

The heat sink is typically coupled to the power module base with a thermal interface material (TIM) dispersed there between

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

Heat sinks operate by transferring the heat away from the heat source of the power module, thereby maintaining the heat source at a lower relative temperature

Methodology Applied
Scientific EffectHeat sink: Heat Sink

Data Source

PatentEP2538440B1Cooling device for a power module, and a related method thereof
Publication Date: 2020.05.06 GENERAL ELECTRIC CO
  • EP2538440B1 patent drawingFigure 1~2
  • EP2538440B1 patent drawingFigure 3~4
  • EP2538440B1 patent drawing

AI summary

A cooling device for a power module having an electronic module disposed on a base plate via a substrate is disclosed. The cooling device includes a heat sink plate having at least one cooling segment. The cooling segment includes an inlet plenum for entry of a cooling medium, a plurality of inlet manifold channels, a plurality of outlet manifold channels, and an outlet plenum. The plurality of inlet manifold channels are coupled orthogonally to the inlet plenum for receiving the cooling medium from the inlet plenum. The plurality of outlet manifold channels are disposed parallel to the inlet manifold channels. The outlet plenum is coupled orthogonally to the plurality of outlet manifold channels for exhaust of the cooling medium. A plurality of millichannels are disposed in the base plate orthogonally to the inlet and the outlet manifold channels. The plurality ofmilli channels direct the cooling medium from the plurality of inlet manifold channels to the plurality of outlet manifold channels.