PAG Lubricant Composition for EV Motor Cooling and Insulation

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Solution Overview

Problem

Current cooling methods for electric vehicle motors and batteries are inadequate, as air cooling is insufficient for high-power engines, water cooling is hindered by electrical conductivity issues, and existing lubricating compositions face oxidation instability, compatibility problems, and environmental concerns.

Innovation Solution

A lubricating composition comprising 70-99% polyalkylene glycol (PAG) obtained by polymerization or copolymerization of alkylene oxides with 2-8 carbon atoms, providing effective cooling and lubrication while maintaining stability, deaeration, anti-corrosion, and environmental safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If water cooling is used for electric motors, then cooling efficiency is improved, but electrical conductivity issues prevent direct contact with motor components

Engineering Contradiction:
Improvecooling efficiencyVSAvoidelectrical conductivity
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent uses an electrically insulating cooling fluid as an intermediary substance between the cooling system and the motor components. This fluid provides efficient heat transfer while maintaining electrical insulation, allowing direct contact with motor parts without the conductivity problems of water.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical and chemical parameters of the cooling fluid by using compounds with specific properties: high heat capacity for efficient cooling, low electrical conductivity for insulation, and appropriate viscosity for heat transfer. This transforms the cooling medium from conductive water to insulating synthetic fluids.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If esters are used in lubricating composition, then lubrication properties are improved, but oxidation instability and compatibility problems with varnishes and seals worsen

Engineering Contradiction:
Improvelubrication propertiesVSAvoidoxidation stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent employs composite lubricating compositions combining multiple base oils (synthetic hydrocarbon oils, esters, and/or ethers) with specific additives. This composite approach achieves reliable lubrication while maintaining oxidation stability and compatibility with motor varnishes and seals through careful formulation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters of the lubricating fluid by selecting base oils with appropriate viscosity grades and stability characteristics, and by formulating specific additive packages that enhance oxidation resistance and material compatibility while maintaining lubrication performance.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If fluorinated compounds are used in lubricating composition, then cooling and lubrication properties are improved, but environmental harm to the ozone layer and greenhouse gas effects worsen

Engineering Contradiction:
Improvecooling propertiesVSAvoidozone layer damage
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and eliminates harmful fluorinated compounds (HCFCs) from the lubricating composition while retaining the essential cooling and lubrication functions through alternative environmentally benign fluids based on synthetic hydrocarbons, esters, and ethers.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the requirement for effective cooling and lubrication into a benefit by using environmentally friendly base oils that naturally provide these functions without the harmful environmental side effects of fluorinated compounds, turning an environmental constraint into a sustainable solution.

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

4Device complexity

If air cooling is used for electric motors, then device complexity is reduced, but cooling efficiency becomes insufficient for high-power motors

Engineering Contradiction:
Improvecooling system complexityVSAvoidcooling efficiency
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The patent transitions from air cooling to liquid hydraulic cooling using electrically insulating fluids. This enables more efficient heat removal through direct liquid contact with motor components via jet cooling systems, while the insulating properties eliminate the need for additional protective casings.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 PAG-based composition offers superior cooling and lubrication properties for electric vehicle motors and batteries, enhancing heat management, reducing the risk of damage, and being environmentally friendly.

Implementation Method 1

a lubricating composition comprising at least one polyalkylene glycol (PAG) obtained by polymerization or copolymerization of alkylene oxides comprising 2 to 8 carbon atoms, preferably 2 to 4 carbon atoms, in an electric vehicle, in which the composition comprises 70 to 99% by weight of PAG relative to the total weight of the composition

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The invention relates to the use of a lubricating composition for cooling and/or lubricating an electric vehicle motor and its various moving parts

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3532577B1Use of a composition for an electric vehicle
Publication Date: 2024.05.08 TOTALENERGIES ONETECH
  • EP3532577B1 patent drawingFigure 1

AI summary

The invention relates to the use of a lubricant composition in order to cool and/or lubricate the engine of an electric vehicle and the different parts thereof, particularly moving parts. In particular, the invention relates to the use of a lubricant composition comprising at least one polyalkylene glycol.