EV Battery Cooling via Dielectric Fluid Spray and Condenser

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Solution Overview

Problem

Existing heat treatment devices for electric vehicle batteries suffer from inhomogeneous cooling, leading to reduced performance and shortened service life due to high thermal resistance and inefficient heat exchange between the cooling fluid and battery cells.

Innovation Solution

A cooling device with a stepped stack configuration of battery cells, each equipped with a condenser and dielectric fluid circuit, where a common dielectric fluid recovery tank and pump recirculate the fluid to ensure uniform cooling by spraying dielectric fluid onto the cells, optimizing heat exchange and reducing thermal resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If heat exchangers with cooling fluid circulation are used to cool battery cells, then cooling capability is provided, but inhomogeneous cooling occurs and thermal resistance increases

Engineering Contradiction:
Improvebattery cell temperatureVSAvoidcooling uniformity
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The battery cooling system is divided into multiple independent cooling channels, each equipped with separate nozzles and flow control mechanisms. This segmentation allows each channel to be optimized independently, ensuring uniform cooling distribution across all battery cells while reducing thermal resistance through targeted cooling zones.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the battery pack are provided with customized cooling characteristics through locally adapted nozzle designs and flow rates. High-heat-generation areas receive intensified cooling while lower-heat areas receive proportionally reduced cooling, achieving homogeneous temperature distribution across the entire battery system.

Inventive Principle:
Principle #3Local quality

2Strength

If cooling plates with thick material are used between cooling fluid and battery cells, then structural strength is provided, but thermal resistance increases

Engineering Contradiction:
Improvecooling plate strengthVSAvoidheat exchange efficiency
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The cooling plate is constructed using composite material structures combining high-strength, low-thermal-resistance materials. This allows the plate to maintain sufficient mechanical strength for structural support while minimizing thermal resistance to improve heat exchange efficiency between the cooling fluid and battery cells.

Inventive Principle:
Principle #40Composite materials

3Temperature

If immersion cooling with two-phase fluid is used, then cooling capability is enhanced, but uniform cooling of cells is not achieved

Engineering Contradiction:
Improvecooling effectivenessVSAvoidcooling uniformity
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

Dielectric fluid is introduced as an intermediary substance between the cooling system and battery cells. This fluid provides excellent thermal contact and heat transfer properties while maintaining electrical insulation, enabling uniform cooling distribution without the shortcomings of direct two-phase fluid immersion.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 provides homogeneous cooling and extended service life by optimizing the heat exchange process, improving the performance and longevity of electric vehicle batteries.

Implementation Method 1

a dielectric fluid circuit (5) which is arranged to spray a dielectric fluid (1) onto a stage (106a, 106b) of battery cells (103)

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

a condenser (3) housing a circuit of cooling fluid (4) which is provided to change from a vapor state to a liquid state the dielectric fluid (1) sprayed on the battery cells (103)

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

a condenser (3) housing a circuit of cooling fluid (4)

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3970227B1Cooling device of an electrical storage system and method using the cooling device
Publication Date: 2023.06.07 VALEO SYST THERMIQUES SAS
  • EP3970227B1 patent drawingFigure 1
  • EP3970227B1 patent drawingFigure 2
  • EP3970227B1 patent drawingFigure 3~4

AI summary

The invention relates to a cooling device (2) of a plurality of battery elements (103) of a motor vehicle, wherein the cooling device (2) comprises a first housing accommodating a plurality of battery element stages (103), each battery element stage (103) being equipped with a condenser (3) provided with a cooling fluid circuit (4), the condenser (3) being associated with at least one dielectric fluid circuit (5) that is configured to project a dielectric fluid onto the battery elements (103) of a same stage and a recovery tank (108) of the dielectric fluid that is common to the plurality of battery element stages (103), the cooling device (2) comprising recirculation means (117) of the dielectric fluid, which are provided with a pump (115) and which connect the recovery tank (108) to a dielectric fluid inlet (23) which the dielectric fluid circuit (5) comprises.