Electric Drivetrain Cooling With Condensation Return Flow

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Solution Overview

Problem

Existing cooling devices for electric drive train components are not efficient in controlling temperature and ensuring a reliable coolant supply, leading to suboptimal performance and lifespan of these components.

Innovation Solution

A cooling device with a heat exchanger that transforms gaseous coolant into liquid coolant, using a coolant collection channel oriented below the heat exchanger to create a suction effect, ensuring continuous coolant flow and efficient heat extraction, and optionally integrating with the electric machine or transmission for enhanced compactness and cooling performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a conventional cooling device uses liquid coolant circulation, then the cooling device can remove heat from the electric drive train component, but the cooling efficiency is limited and a large amount of coolant is required to achieve sufficient cooling

Engineering Contradiction:
Improvecooling efficiencyVSAvoidcoolant amount
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent utilizes phase transition of coolant from liquid to gas state during evaporation to absorb large amounts of heat from the electric drive train component, and then condenses the gas back to liquid in the heat exchanger. This phase change mechanism enables high cooling efficiency with a smaller quantity of coolant compared to conventional liquid-only cooling systems.

Inventive Principle:
Principle #36Phase transitions

2Volume of moving object

If the cooling device uses a compact design, then the device size is reduced, but the heat exchanger may not effectively condense the gaseous coolant into liquid coolant

Engineering Contradiction:
Improvecooling device sizeVSAvoidcoolant condensation effectiveness
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent positions the end of the coolant collection channel at a lower vertical level than the heat exchanger, utilizing gravitational force in the vertical dimension to create a suction effect. This dimensional arrangement ensures reliable coolant condensation and continuous circulation while maintaining a compact overall device structure.

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

3Device complexity

If the coolant collection channel is arranged horizontally, then the device structure is simplified, but the condensed coolant cannot be effectively collected and returned to the heat exchanger

Engineering Contradiction:
Improvecoolant collection channel structureVSAvoidcoolant circulation efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent transitions from a horizontal to a vertical arrangement of the coolant collection channel, utilizing the vertical dimension and gravitational force to create a suction effect that draws condensed coolant back to the heat exchanger. This vertical configuration enhances coolant circulation efficiency while maintaining structural simplicity.

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

4Device complexity

If the cooling device operates without a suction effect, then the system is simpler, but the continuous supply of liquid coolant to the electric drive train component cannot be ensured

Engineering Contradiction:
Improvecooling device structureVSAvoidcoolant supply continuity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent employs a self-service mechanism where the phase change of coolant from gas to liquid in the heat exchanger naturally creates a suction effect due to density difference and gravitational force. This self-generated suction ensures continuous circulation and supply of liquid coolant without requiring additional active pumping components.

Inventive Principle:
Principle #25Self-service

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 controls the temperature of electric drive train components by efficiently extracting heat and providing a consistent supply of liquid coolant, enhancing performance and lifespan while maintaining a compact design.

Implementation Method 1

a heat exchanger (26) being configured to extract heat from the gaseous coolant such that the gaseous coolant is at least partially transformed into liquid coolant

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 2

at least a portion of the coolant is gasified or vaporized when being in contact with hot or warm parts of the electric drivetrain component

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

Since the condensed coolant is driven at least partially along the vertical direction by gravity, it creates a suction effect moving additional gaseous coolant into the heat exchanger

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP4371795A1Cooling device for an electric drive train component, electric drive train assembly, method for operating a cooling device, method for cooling an electric drive train component, and vehicle
Publication Date: 2024.05.22 VOLVO CAR CORP
  • EP4371795A1 patent drawingFigure 1~2
  • EP4371795A1 patent drawingFigure 3~4
  • EP4371795A1 patent drawingFigure 5~6

AI summary

The disclosure relates to a cooling device (24) for an electric drive train component (21). The cooling device (24) comprises a coolant inlet port (32) being configured to receive gaseous coolant (G) from the electric drive train component (21) and a coolant outlet port (34) being configured to deliver liquid coolant (L) to the electric drive train component (21). Moreover, the cooling device (24) comprises a heat exchanger (26) being configured to extract heat from the gaseous coolant (G) such that the gaseous coolant (G) is at least partially transformed into liquid coolant (L). The cooling device (24) also comprises a coolant collection channel (40). An end of the coolant collection channel (40) being arranged adjacent to the coolant outlet port (34) is located on a lower vertical level than the heat exchanger (26). Furthermore, an electric drive train assembly (12) comprising an electric machine (18) and such a cooling device (24) is explained. Also, a method for operating a cooling device (24) for an electric drive train component (21) and a method for cooling an electric drive train component (21) are presented. Moreover, a vehicle (10) comprising an electric drive train assembly (12) is shown.