Microporous Wick Cooling for High-Power Thermal Management

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Solution Overview

Problem

Existing cooling systems for high-power electronic devices on direct-bonded copper substrates face limitations in thermal dissipation due to restricted back-side cooling surface area and thermal resistance, particularly with liquid impingement flow rates, and are often bulky and costly.

Innovation Solution

A cooling apparatus featuring a microporous wick formation thermally coupled to a metallic substrate, utilizing active liquid pumping and passive capillary action for enhanced heat removal through liquid-to-vapor phase-change, with a liquid delivery head directing microjets onto the substrate to facilitate improved heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If macro-scale fins are attached to DBC substrates to increase cooling surface area, then thermal dissipation capability is improved, but the liquid impingement path is blocked and system cost increases

Engineering Contradiction:

Improvethermal dissipation capabilityVSAvoidliquid impingement path blockage

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The patent transitions from macro-scale two-dimensional fin structures to micro-scale three-dimensional porous wick structures. The microporous wicks provide extensive internal surface area through their porous network, achieving enhanced heat transfer without blocking the liquid impingement path from above, thus resolving the contradiction between thermal dissipation and liquid flow accessibility.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent employs microporous wick materials with controlled pore structures to create extensive internal surface area for heat transfer. These porous structures allow liquid to penetrate and distribute throughout the volume, providing efficient capillary wicking and evaporation surfaces without the geometric constraints of traditional fins, thereby improving thermal dissipation while maintaining liquid impingement access.

Inventive Principle:

Principle #31Porous materials

2Temperature

If no-fin DBC solutions with direct liquid impingement are used, then thermal resistance over the base plate is reduced, but back-side cooling surface area is substantially lost

Engineering Contradiction:

Improvethermal resistance over base plateVSAvoidback-side cooling surface area

Core Design Contradiction:

TemperatureVSArea of stationary object

Solution Approach 1:

The microporous wick formation attached to the DBC substrate provides extensive internal surface area through its porous structure. This allows the system to maintain direct liquid impingement benefits while recovering cooling surface area through the wick's internal porosity, effectively resolving the trade-off between thermal resistance reduction and cooling surface area preservation.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent creates a composite structure combining the DBC substrate with microporous wick material. This composite approach integrates the thermal conductivity benefits of the metal substrate with the high surface area-to-volume ratio of the porous wick, achieving both low thermal resistance and sufficient cooling surface area simultaneously.

Inventive Principle:

Principle #40Composite materials

3Temperature

If evaporative spray cooling with custom base plates is used, then heat transfer is enhanced, but system bulk and cost increase

Engineering Contradiction:

Improveheat transfer enhancementVSAvoidsystem bulk

Core Design Contradiction:

TemperatureVSWeight of stationary object

Solution Approach 1:

The microporous wick structure provides evaporative cooling functionality within a compact form factor. The porous material's capillary action and internal surface area enable efficient heat transfer without requiring the bulky custom base plate structures traditional spray cooling systems need, thus achieving heat transfer enhancement with reduced system bulk.

Inventive Principle:

Principle #31Porous 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

The solution effectively increases power dissipation for high-power devices by leveraging microporous wick structures and active liquid pumping, enhancing thermal management while reducing system bulk and cost.

Implementation Method 1

drawing a portion of the liquid through a microporous wick structure that is thermally coupled to the thermally conductive substrate using capillary action

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

removing heat from the thermally conductive substrate using liquid-to-vapor phase-change of the portion of liquid

Methodology Applied

Scientific EffectLiquid-to-vapor phase-change: Phase Change

Implementation Method 3

at least one microporous wick formation in thermal communication with the metallic face

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS10006720B2System for using active and passive cooling for high power thermal management

Publication Date: 2018.06.26 TELEDYNE SCIENTIFIC & IMAGING LLC

AI summary

A cooling system that includes a substrate having a metallic face, at least one microporous wick formation in thermal communication with the metallic face, and a liquid delivery head positioned in complementary opposition to the metallic face, the liquid delivery head having at least one nozzle for directing a liquid towards the metallic face.