EV Battery Coolant with Low Conductivity and Viscosity

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Solution Overview

Problem

Conventional battery coolants for electric vehicles face issues with high conductivity leading to potential short circuits, high ion elution performance causing radiator material dissolution, and low viscosity at low temperatures increasing water pump load, while non-aqueous materials offer poor cooling performance.

Innovation Solution

A battery coolant composition comprising 90% or more of non-aqueous propylene carbonate or butylene carbonate with 3% or less water and optional glycols and additives like benzotriazole, providing low conductivity, ion elution performance, and viscosity at low temperatures, while maintaining cooling performance equivalent to aqueous coolants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If aqueous coolant composition is used, then cooling performance is improved, but conductivity increases causing potential short circuits

Engineering Contradiction:
Improvecooling performanceVSAvoidconductivity
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters by using non-aqueous base materials (ethylene glycol, propylene glycol) instead of water, and controls the concentration of additives (ionic liquids, salts) to maintain low conductivity while achieving adequate cooling performance through optimized formulation

Inventive Principle:
Principle #35Parameter changes

2Temperature

If aqueous coolant with high ion elution performance is used, then cooling efficiency is improved, but radiator material dissolution occurs

Engineering Contradiction:
Improvecooling efficiencyVSAvoidion elution
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical environment by using non-aqueous base materials that do not promote ion elution, and carefully selects and controls additive concentrations to achieve cooling efficiency without the harmful ion elution effect that occurs with aqueous coolants

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the typically harmful effect of high conductivity and ion elution into a benefit by using ionic liquids and salts in controlled concentrations within a non-aqueous base, where they provide necessary electrochemical stability and cooling performance without causing radiator material dissolution

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

3Reliability

If non-aqueous materials are used, then conductivity is reduced, but cooling performance deteriorates

Engineering Contradiction:
ImproveconductivityVSAvoidcooling performance
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent creates a composite coolant formulation by combining non-aqueous base materials (ethylene glycol, propylene glycol) with carefully selected and concentrated additives (ionic liquids, salts), achieving a synergistic effect where the composite provides both low conductivity and adequate cooling performance

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the concentration parameters of additives within the non-aqueous base to achieve the necessary cooling performance while maintaining low conductivity, using precise formulation control to balance these competing requirements

Inventive Principle:
Principle #35Parameter changes

4Use of energy by moving object

If viscosity at very low temperature is reduced, then water pump load decreases, but freezing protection capability is compromised

Engineering Contradiction:
Improvewater pump loadVSAvoidfreezing protection
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent changes the physical parameters of the coolant by using non-aqueous base materials with inherently lower viscosity at low temperatures, and optimizes the composition to maintain freezing protection capability while reducing viscosity to minimize water pump load

Inventive Principle:
Principle #35Parameter changes

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 coolant achieves low conductivity, reduced ion elution, and viscosity at low temperatures, preventing short circuits and radiator material dissolution, and minimizing water pump load, while maintaining effective cooling performance.

Implementation Method 1

a battery coolant for an electric vehicle that has a low conductivity, a low ion elution performance, a low viscosity at a very low temperature, and a cooling performance equivalent to that of an aqueous coolant composition in a driving temperature range

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a battery coolant for an electric vehicle containing: at least one kind of carbonates selected from the group consisting of propylene carbonate and butylene carbonate

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentUS11108102B2Coolant
Publication Date: 2021.08.31 TOYOTA JIDOSHA KK

AI summary

The present disclosure provides a battery coolant for an electric vehicle that has a low conductivity, a low ion elution performance, a low viscosity at a very low temperature, and a cooling performance equivalent to that of an aqueous coolant composition in a driving temperature range. The present disclosure relates to a battery coolant for an electric vehicle containing at least one kind of carbonates selected from the group consisting of propylene carbonate and butylene carbonate in an amount of 90 mass % or more with respect to a total mass of the coolant and water in an amount of 3 mass % or less with respect to the total mass of the coolant.