Power Module Baseplate Cooling Surface for Lower Thermal Resistance

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Solution Overview

Problem

Conventional baseplates for power modules lack effective heat dissipation mechanisms, leading to excessive temperature issues due to inefficient thermal management, especially in high heat generation scenarios like automotive applications.

Innovation Solution

A baseplate with a modified cooling structure featuring a surface roughness of Ra > 1 µm and protrusions with a height of 2 µm or more, comprising pin-fins or ribs, which enhances heat transfer efficiency by promoting turbulent flow and increasing the thermal interface area, formed through methods like etching, grinding, or coating with materials like nickel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional smooth cooling structures are used, then manufacturing is simpler, but heat dissipation efficiency is insufficient

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidsurface structure complexity
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent changes the surface roughness parameter from conventional smooth surfaces (Ra < 1 μm) to specifically engineered rough surfaces (Ra ≥ 1 μm). This parameter change increases the heat transfer coefficient by promoting turbulent flow and enhancing thermal convection, thereby improving heat dissipation efficiency while maintaining manufacturing feasibility through established processes like sandblasting, chemical etching, or mechanical grinding.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a micro-rough surface structure that functions similarly to porous materials, increasing the effective heat transfer surface area. The protrusions and valleys on the cooling structure surface enhance fluid turbulence and extend the thermal interaction path between the coolant and cooling structure, improving heat dissipation without significantly increasing manufacturing complexity.

Inventive Principle:
Principle #31Porous materials

2Reliability

If cooling structure surface is modified with protrusions and roughness, then heat transfer coefficient increases, but manufacturing complexity increases

Engineering Contradiction:
Improveheat transfer coefficientVSAvoidcooling structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent modifies the surface roughness parameter (Ra ≥ 1 μm) and introduces controlled protrusions (height ≥ 2 μm) on the cooling structure. These parameter changes enhance the heat transfer coefficient by promoting turbulent flow and increasing thermal convection efficiency, while the modifications can be achieved through conventional manufacturing processes, limiting the increase in device complexity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies surface modifications (protrusions and roughness) specifically to the cooling structure surface that contacts the coolant, while other parts of the device maintain conventional designs. This localized application of complexity ensures that the heat transfer coefficient is improved without unnecessarily complicating the entire device structure.

Inventive Principle:
Principle #3Local quality

3Temperature

If conventional baseplates are used, then design is simpler, but thermal resistance is too high

Engineering Contradiction:
Improvethermal resistanceVSAvoidbaseplate structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent changes the baseplate cooling structure from conventional smooth surfaces to rough surfaces with protrusions (Ra ≥ 1 μm, height ≥ 2 μm). This parameter change reduces thermal resistance by enhancing convective heat transfer and increasing the effective heat transfer area, while the modifications can be integrated into existing baseplate manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent adds surface dimensionality through protrusions and roughness features on the cooling structure. This transforms the traditionally two-dimensional heat transfer surface into a three-dimensional micro-structured surface, increasing the heat transfer area and reducing thermal resistance without significantly increasing overall device complexity.

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

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 significantly improves heat dissipation, enabling higher current capability, reduced size, and increased reliability by enhancing the heat transfer coefficient and reducing thermal resistance, while also providing corrosion protection.

Implementation Method 1

enhances heat transfer efficiency by promoting turbulent flow

Methodology Applied
Scientific EffectTurbulent flow: Turbulence

Implementation Method 2

heat transfer coefficient

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 3

heat dissipation

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4187591B1Baseplate and method for manufacturing a baseplate for a power module and semiconductor device
Publication Date: 2025.01.01 HITACHI ENERGY LTD
  • EP4187591B1 patent drawingFigure 1
  • EP4187591B1 patent drawingFigure 2
  • EP4187591B1 patent drawingFigure 3

AI summary

A baseplate (1) for a power module (30) comprises a lower part (10) and an upper part (20). The lower part (10) comprises a cooling structure (11) configured to be in contact with a coolant during operation of the power module (30). The upper part (20) is coupled to the lower part (10). The cooling structure (11) faces away from the upper part (20) and comprises a surface (12) with a given surface structure (13, 14) including at least one of a mean roughness Ra &gt; 1 µm and a plurality of protrusions with a respective height (H) of 2 µm or more with respect to a surface normal (A) perpendicular to the surface (12) of the cooling structure (11).