Embedded PCB Cooling Path for Direct Hot-Spot Heat Removal

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional cooling methods for heat-generating components on printed circuit boards (PCBs) face challenges due to high thermal resistance from intervening layers, making it difficult to maintain proper case or package temperature, especially for high-power electronics like GaN transistors.

Innovation Solution

An embedded PCB with a micro immersion cooling channel that uses a cryogenic coolant and non-conductive fluid, where a lid defines the cooling path and is sealed to the PCB with Indium, allowing direct fluid communication with heat-generating components, eliminating the need for intervening thermal interface materials and providing efficient heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional cold plate cooling methods are used, then cooling coverage is provided, but high thermal resistance from intervening layers prevents effective heat dissipation

Engineering Contradiction:
Improvecase or package temperatureVSAvoidthermal performance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent removes the cold plate intermediary component entirely, replacing it with direct immersion cooling where coolant flows directly through channels formed in the PCB substrate, eliminating thermal interface materials and intervening layers that cause high thermal resistance

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The cooling channels are nested directly within the PCB substrate layers, with heat-generating components positioned to conduct heat directly into the coolant channels, creating a integrated thermal management structure that eliminates separate cooling components

Inventive Principle:
Principle #7Nested doll (Nesting)

2Temperature

If 3D printing is used to create microfluidic channels, then direct cooling is achieved, but fabrication complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvecooling efficiencyVSAvoidfabrication technique
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent transitions from additive manufacturing (3D printing) to subtractive manufacturing (laser drilling and routing) parameters, using standard PCB fabrication techniques to create cooling channels that match the form factor and material properties of conventional PCBs

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The PCB substrate serves multiple functions simultaneously: electrical circuit board, structural support, and cooling channel conduit, eliminating the need for separate 3D-printed cooling components and integrating thermal management into the existing PCB manufacturing ecosystem

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

3Ease of manufacture

If conventional embedded PCB designs are used, then manufacturing is simplified, but thermal performance is insufficient for high power electronics

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidthermal performance
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent transitions from surface-mounted or top-side embedded cooling to through-substrate cooling channels that extend through the entire PCB thickness, allowing direct thermal contact between heat-generating components and coolant while maintaining standard PCB manufacturing processes

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

Solution Approach 2:

The patent uses copper-lined cooling channels within the PCB substrate, combining the electrical and thermal conductivity of copper with the structural and insulating properties of the PCB material, achieving superior thermal performance while maintaining manufacturing compatibility

Inventive Principle:
Principle #40Composite materials

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 solution achieves effective heat dissipation with reduced thermal cross-talk and temperature differential, enabling increased power density and faster temperature control without requiring conventional cold plates or thermal insulation, thus addressing the limitations of existing cooling methods.

Implementation Method 1

A cooling path extends in a coolant flow direction from an inlet end of the cooling path to an outlet end of the cooling path. The cooling path is in fluid communication with the at least one heat generating component.

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

The at least one heat generating component can include a die embedded in the first PCB

Methodology Applied
Scientific EffectConduction (thermal): Conduction (thermal)

Implementation Method 3

The seal element can include Indium

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4326012A1Immersion cooling electronic devices
Publication Date: 2024.02.21 HAMILTON SUNDSTRAND CORP
  • EP4326012A1 patent drawingFigure 1~2
  • EP4326012A1 patent drawingFigure 3~4
  • EP4326012A1 patent drawingFigure 5~6

AI summary

Embodiments have two approaches as follows: (1) Embedded PCB-based fabrication and (2) PCB assembly-based fabrication. An embedded printed circuit board (PCB) type approach involves the creation of a space of coolant direct interconnection, using immersion cooling to link on any type of power semiconductor device hot spots to convectively and evaporatively cool directly. This means fabricating PCB embedded channels, to utilize the microgap between die and PCB as the cooling channel. A printed circuit board (PCB) assembly embodiment includes a PCB having at least one heat generating component (104). A lid (106) is mounted to the PCB, wherein the lid (106) defines a cooling path (108) therein extending in a coolant flow direction from an inlet end of the cooling path (108) to an outlet end of the cooling path (108).