Split Refrigerant Path in Power Converters for Lower-Cost Cooling

Solution Overview

Problem

Conventional power conversion devices for electric vehicles face increased manufacturing costs due to complex cooling flow paths, which complicate the cooling of various components and raise costs.

Innovation Solution

A power conversion device design featuring a housing with a refrigerant flow path that includes a first flow path portion outside the accommodation space to cool a capacitor module and a second flow path portion inside the space to cool a power module, optimizing cooling based on each module's calorific value, with the refrigerant flow path structured to efficiently cool both components while minimizing manufacturing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the entire cooling flow path is disposed in the housing to cool various parts, then the cooling coverage is improved, but the flow path becomes complicated and manufacturing cost increases

Engineering Contradiction:

Improvecooling coverageVSAvoidflow path complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The cooling flow path is divided into two separate parts: a first flow path portion disposed outside the accommodation space and a second flow path portion disposed inside the accommodation space. This segmentation allows each part to be optimized independently, reducing overall complexity while maintaining comprehensive cooling coverage for different modules.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first flow path portion is extracted from the accommodation space and disposed outside the housing. This extraction simplifies the internal structure by removing complex routing requirements from inside the accommodation space, while still enabling cooling of modules through the lid.

Inventive Principle:

Principle #2Taking out (Extraction)

2Temperature

If the entire cooling flow path is disposed in the housing to cool various parts, then the cooling coverage is improved, but the manufacturing cost increases

Engineering Contradiction:

Improvecooling coverageVSAvoidmanufacturing cost

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The cooling flow path is divided into two separate parts: a first flow path portion disposed outside the accommodation space and a second flow path portion disposed inside the accommodation space. This segmentation allows each part to be optimized independently, reducing overall complexity while maintaining comprehensive cooling coverage for different modules.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first flow path portion is extracted from the accommodation space and disposed outside the housing. This extraction simplifies the internal structure by removing complex routing requirements from inside the accommodation space, while still enabling cooling of modules through the lid.

Inventive Principle:

Principle #2Taking out (Extraction)

3Temperature

If a complex cooling flow path is used to cool various parts, then the heat management effectiveness is improved, but the device size and weight increase

Engineering Contradiction:

Improveheat management effectivenessVSAvoiddevice weight

Core Design Contradiction:

TemperatureVSWeight of stationary object

Solution Approach 1:

The cooling flow path is divided into two separate parts: a first flow path portion disposed outside the accommodation space and a second flow path portion disposed inside the accommodation space. This segmentation allows each part to be optimized independently, reducing overall complexity while maintaining comprehensive cooling coverage for different modules.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first flow path portion utilizes the external surface of the lid as a cooling interface, transitioning the cooling approach from internal three-dimensional routing to external two-dimensional heat transfer. This dimensional change reduces the space and material required for the cooling system while maintaining effective heat dissipation.

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

This design efficiently cools both the capacitor and power modules, reducing the overall manufacturing cost and maintaining effective heat management, while also minimizing the device's size and weight, thus preserving vehicle boarding space.

Implementation Method 1

a first flow path portion that is disposed outside the accommodation space and cools the first module via the lid

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a second flow path portion that is disposed inside the accommodation space and cools the second module

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS20240373603A1Power conversion device and drive device

Publication Date: 2024.11.07 NIDEC CORP(JP)

AI summary

A power conversion device includes a first module that is a heating element, a second module that is a heating element having a larger calorific value than the first module, a housing having an accommodation space for accommodating the first module and the second module, and a refrigerant flow path through which a refrigerant flows. The housing has a lid that covers the accommodation space. The refrigerant flow path includes a first flow path portion that is disposed outside the accommodation space and cools the first module via the lid, and a second flow path portion that is disposed inside the accommodation space and cools the second module.