Dielectric Oleaginous Coolant for EV Battery Pack Isolation

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Solution Overview

Problem

Traditional heat transfer fluids used in electric vehicle battery packs are prone to freezing, exhibit high electrical conductivity leading to corrosion and short-circuiting, and have increased flammability when aerosolized, necessitating a more effective and safer alternative.

Innovation Solution

A dielectric oleaginous heat transfer fluid comprising a non-conductive, non-aqueous, and non-water miscible oil component combined with a high molecular weight polymer additive, which reduces electrical conductivity and flammability while maintaining effective heat transfer properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If traditional water-glycol heat transfer fluids are used, then heat transfer effectiveness is improved, but electrical conductivity increases leading to corrosion and short-circuiting

Engineering Contradiction:
Improveheat transfer effectivenessVSAvoidelectrical conductivity
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent changes the fundamental parameter of the heat transfer fluid from aqueous (water-based) to oleaginous (oil-based). This parameter change transforms the fluid from electrically conductive to electrically insulating, while maintaining heat transfer capability through the oil medium. The dielectric oil serves as both the heat transfer medium and electrical insulator, resolving the contradiction between heat transfer effectiveness and electrical conductivity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite heat transfer system by combining dielectric oil with specialized additives including viscosity modifiers, corrosion inhibitors, and anti-foaming agents. This composite formulation achieves both effective heat transfer and electrical insulation properties, while the water-immiscible nature prevents electrolysis and corrosion issues associated with traditional conductive fluids.

Inventive Principle:
Principle #40Composite materials

2Reliability

If oil based fluids are used for heat transfer, then electrical conductivity is reduced, but flammability increases when aerosolized

Engineering Contradiction:
Improveelectrical conductivityVSAvoidflammability
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical parameters of the oil-based fluid by selecting specific dielectric oils with high flash points and incorporating flame retardant additives. This parameter modification reduces the flammability hazard while maintaining the electrical insulation properties and heat transfer effectiveness of the oleaginous base fluid.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent acknowledges the flammability risk of oil-based fluids but converts this potential harm into a benefit by carefully selecting oils with appropriate viscosity and flash point characteristics. The water-immiscible property that could lead to aerosolization is managed through viscosity modification and operational controls, transforming a potential hazard into a manageable parameter.

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

3Reliability

If water-immiscible oil component is used, then flammability and electrical conductivity are reduced, but viscosity may increase affecting fluid flow

Engineering Contradiction:
Improveflammability and electrical conductivityVSAvoidfluid flow properties
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent carefully selects and formulates the dielectric oil to achieve optimal viscosity parameters. By controlling the molecular weight, saturation level, and additive package, the oil maintains low enough viscosity for effective fluid flow and heat transfer while preserving the electrical insulation and flammability reduction benefits of the water-immiscible oleaginous base.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different functional properties to different aspects of the fluid: the base oil provides electrical insulation and flammability resistance, while viscosity modifiers and additives are added in specific concentrations to optimize fluid flow characteristics. This local quality approach ensures each property is optimized without compromising the others.

Inventive Principle:
Principle #3Local quality

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 dielectric oleaginous heat transfer fluid effectively cools electrical components, reduces the risk of corrosion and short-circuiting, and decreases flammability, making it suitable for use in electric vehicle battery packs and other electrical systems.

Implementation Method 1

a heat transfer fluid that facilitates absorbing and dissipating the heat from the power source

Methodology Applied
Scientific EffectHeat absorption: Absorption (EM radiation)

Implementation Method 2

The dielectric oleaginous heat transfer fluid effectively cools electrical components

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

a heat transfer fluid that facilitates absorbing and dissipating the heat from the power source

Methodology Applied
Scientific EffectHeat dissipation: Convection

Implementation Method 4

a dielectric oleaginous heat transfer fluid with low electrical conductivity and low flammability

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 5

If the coolant is electrically conductive, it can bridge terminals having relatively large potential differences. That bridging may start an electrolysis process

Methodology Applied
Scientific EffectElectrolysis prevention: Electrolysis

Data Source

PatentUS20240047778A1Organic heat transfer system, method, and fluid
Publication Date: 2024.02.08 THE LUBRIZOL CORP

AI summary

The disclosed technology relates to a dielectric oleaginous heat transfer system, method, and fluid comprising a) a non-conductive, non-aqueous and non-water miscible dielectric oleaginous fluid and b) at least one high molecular weight. In particular, the technology relates to a dielectric oleaginous heat transfer system, method, and fluid with low electrical conductivity, low shear viscosity, and low flammability, that provides temperature reduction in a heat transfer system, such as that for cooling a battery pack or a power system of an electric vehicle.