Cooling Plate Bubble Reservoir for Low-Flow Power Conversion Cooling

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Solution Overview

Problem

Existing power conversion devices face inefficiencies in cooling due to bubbles staying on the upper wall surface of the cooling case, particularly at low refrigerant flow speeds, which reduces the cooling efficiency of semiconductor modules.

Innovation Solution

A power conversion device with a cooling plate configuration that includes a first flow path for cooling a first cooling target and a second flow path with a bubble reservoir positioned above the first flow path, allowing bubbles to be stored while coolant flows, ensuring effective cooling of both targets even at low flow speeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the refrigerant inlet pipe and outlet pipe are positioned above the upper wall surface of the cooling case, then bubbles can be less likely to stay in the cooling case, but when the flow speed of the refrigerant is low, bubbles may still stay on the upper wall surface and cooling efficiency is reduced

Engineering Contradiction:
Improvecooling efficiencyVSAvoidbubble accumulation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The cooling case is divided into distinct functional zones: a first flow path for coolant flow, a second flow path downstream, and a bubble reservoir positioned above the first flow path. This segmentation separates the bubble accumulation zone from the coolant flow zones, allowing bubbles to be contained in the reservoir while maintaining efficient cooling in the flow paths.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bubble reservoir acts as an intermediary zone between the coolant inlet and outlet areas. It provides a designated space where bubbles can accumulate without interfering with the coolant flow paths, effectively mediating between the need for continuous coolant circulation and the need to manage bubble presence.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If bubbles are mixed in the coolant at low flow speed, then bubbles may stay on the upper wall surface of the flow path, but increasing flow speed may increase energy consumption

Engineering Contradiction:
Improvecooling efficiencyVSAvoidcoolant circulation energy
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The bubble reservoir converts the harmful effect of bubble accumulation into a beneficial by providing a designated storage zone. Instead of bubbles interfering with cooling by staying on upper surfaces, they are channeled into the reservoir where they can accumulate without harming the cooling process, effectively turning a problem into a solution.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

Different regions of the cooling case are given different functional qualities: the first and second flow paths are optimized for coolant flow and heat transfer, while the bubble reservoir is optimized for bubble accumulation. This local differentiation allows each zone to perform its specific function efficiently without compromising the other.

Inventive Principle:
Principle #3Local quality

3Reliability

If the bubble reservoir is positioned above the first flow path, then bubbles can be stored while coolant flows, but the structure becomes more complex

Engineering Contradiction:
Improvecooling efficiencyVSAvoidcooling plate structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bubble reservoir is merged with the cooling plate structure rather than being a separate component. The reservoir is formed as an integrated cavity within the cooling plate, combining the cooling function and bubble management function into a single unified structure, thereby reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bubble reservoir is positioned in the vertical dimension above the first flow path, utilizing the third dimension (height) to create storage space without interfering with the horizontal coolant flow paths. This dimensional arrangement allows bubble storage and coolant flow to coexist without requiring additional horizontal space or complex routing.

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 configuration effectively prevents bubbles from hindering coolant flow, ensuring reliable cooling of electronic components by separating bubble presence areas and facilitating efficient discharge of bubbles, thereby maintaining optimal cooling efficiency.

Implementation Method 1

a bubble reservoir positioned above the first flow path and configured to store a bubble while causing the coolant to flow

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

a cooling plate configured to allow a coolant for cooling the plurality of electronic components to flow therein

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP4597820A1Power conversion device
Publication Date: 2025.08.06 AISIN CORP
  • EP4597820A1 patent drawingFigure 1
  • EP4597820A1 patent drawingFigure 2
  • EP4597820A1 patent drawingFigure 3

AI summary

A power conversion device (B) includes: a plurality of electronic components (66a, 70a); and a cooling plate (11, 12) configured to allow a coolant for cooling the plurality of electronic components to flow therein. The plurality of electronic components include at least a first cooling target and a second cooling target. The cooling plate includes a first flow path (11C) formed in a horizontal direction and configured to cool the first cooling target, and a second flow path (11D) disposed downstream of the first flow path and configured to cool the second cooling target. The second flow path includes a bubble reservoir (80) positioned above the first flow path and configured to store a bubble while causing the coolant to flow.