Double-Sided Liquid Cooling for Semiconductor Power Modules

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Solution Overview

Problem

Conventional semiconductor power modules face limitations in heat dissipation, primarily due to thermal paths being comparably long and inefficient, which restricts their current capability and increases the number of modules required in applications, especially in high-voltage scenarios.

Innovation Solution

A semiconductor power device with a double-sided liquid cooling system, featuring upper and lower flow sections with distinct flow directions, allowing coolant to flow through both sections to provide effective heat dissipation from both the top and bottom sides of the power module, reducing thermal resistance and enhancing cooling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional single-sided cooling is used, then the structure is simple, but the heat dissipation efficiency is insufficient leading to long thermal paths

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

Solution Approach 1:

The cooling system is segmented into two independent flow sections: an upper flow section with inlet 12 and outlet 13, and a lower flow section with inlet 22 and outlet 23. Each section has its own coolant flow path (upper flow path 15 and lower flow path 25 respectively), allowing separate cooling of different regions of the power module 3 to reduce thermal paths and improve heat dissipation efficiency

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cooling system transitions from single-sided to double-sided cooling by adding the upper flow section above the power module 3 and the lower flow section below it. This three-dimensional arrangement with coolant flowing in opposite directions (effective upper flow direction 11 and effective lower flow direction 21) creates multiple thermal dissipation pathways, significantly reducing thermal resistance

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

2Productivity

If the number of power modules is increased to achieve required current capability, then the current capability is sufficient, but the cost and system complexity increase

Engineering Contradiction:
Improvecurrent capabilityVSAvoidnumber of power modules
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention changes the thermal management parameters by implementing double-sided liquid cooling with optimized flow paths and opposite flow directions. This improves the heat dissipation capacity of each individual power module 3, allowing fewer modules to achieve the same total current capability, thereby reducing system complexity and cost

Inventive Principle:
Principle #35Parameter changes

3Temperature

If coolant flow paths are optimized for single-sided cooling, then the cooling system is simple, but temperature homogeneity across chips is poor

Engineering Contradiction:
Improvetemperature homogeneityVSAvoidflow path configuration
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling system divides the thermal management into segmented flow paths: upper flow path 15 for cooling the upper surface of power module 3, and lower flow path 25 for cooling the lower surface. This segmentation allows independent optimization of each cooling zone, improving temperature homogeneity across all chips by addressing thermal hotspots from multiple directions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention inverts the conventional single-direction cooling approach by implementing counter-flow cooling where the effective upper flow direction 11 and effective lower flow direction 21 are opposite to each other. This counter-flow configuration optimizes heat extraction efficiency and promotes more uniform temperature distribution across the power module 3

Inventive Principle:
Principle #13The other way round (Inversion)

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 significantly improves heat dissipation, allowing for a higher current capability at a given maximum chip temperature, reducing the number of power modules needed and lowering costs, while ensuring more homogeneous chip temperatures across multiple modules, thereby increasing reliability and reducing temperature differences.

Implementation Method 1

The semiconductor power device is configured such that during operation a coolant flows through the upper and the lower flow section providing a double-sided liquid cooling of the power module

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a coolant flows through the upper and the lower flow section providing a double-sided liquid cooling of the power module

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4266365A1Semiconductor power device, semiconductor power system and method for cooling a semiconductor power device
Publication Date: 2023.10.25 HITACHI ENERGY LTD
  • EP4266365A1 patent drawingFigure 1
  • EP4266365A1 patent drawingFigure 2
  • EP4266365A1 patent drawingFigure 3

AI summary

A effective lower flow direction comprises power module (3) and a housing (2) that is arranged on an upper surface (9) of the power module (3) defining an upper flow section (10) for liquid cooling of the power module (3) in between. The upper flow section (10) comprises an inlet (12), an outlet (13) and a given upper flow path (15) in between defining an effective upper flow direction (11). Further, a cooling unit (5) is arranged on the lower surface (9) of the power module (3) defining a lower flow section (20) for liquid cooling of the power module (3) in between. The lower flow section (20) comprises an inlet (22), an outlet (23) and a given lower flow path (25) in between defining an effective lower flow direction (21), such that during operation a coolant flows through the upper and the lower flow section (10, 20) providing a double-sided liquid cooling of the power module (3). The effective upper flow direction (11) is different from the effective lower flow direction (21), and the inlet (12) of the upper flow section (10) and the outlet (23) of the lower flow section (20) are fluidically connected with each other.