Dual-Circuit Battery Cooling With Dielectric Immersion for Fast Charging

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Solution Overview

Problem

Existing cooling systems for battery-electric vehicles are inadequate for efficiently managing the heat generated during fast charging and high-power operation, leading to increased contact resistance, wear, and potential damage to charging components, while also posing safety risks due to complex fluid-electrical separation requirements.

Innovation Solution

A dual cooling system with a first coolant circuit for general vehicle components and a second coolant circuit for high-voltage components, utilizing a dielectric coolant for direct contact immersion cooling of battery cells and integrating thermal management modules to regulate temperature independently in separate sub-circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If fast charging is implemented to reduce charging time, then charging speed is improved, but heat generation increases causing temperature rise and contact resistance

Engineering Contradiction:
Improvecharging speedVSAvoidtemperature of charging components
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The cooling system is divided into two separate circuits: a first cooling circuit for low-voltage components and a second cooling circuit for high-voltage components. This segmentation allows independent temperature control for different components, enabling effective cooling of charging components during fast charging without compromising other vehicle systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A dielectric coolant is introduced as an intermediary substance in the second cooling circuit. This coolant provides both cooling functionality and electrical insulation, allowing direct contact with high-voltage charging components while preventing electrical hazards. The dielectric coolant enables efficient heat transfer from charging components without compromising safety.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If a single cooling circuit is used to cool all components, then system complexity is reduced, but temperature control precision for high-voltage components deteriorates

Engineering Contradiction:
Improvecooling system structureVSAvoidtemperature control precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The cooling system is divided into two separate circuits: a first cooling circuit for low-voltage components and a second cooling circuit for high-voltage components. This segmentation allows independent temperature control for different components, enabling effective cooling of charging components during fast charging without compromising other vehicle systems.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If fluid and electrical connections are integrated at the charging port, then connection complexity is reduced, but safety risks increase due to potential leaks and contamination

Engineering Contradiction:
Improveconnection structureVSAvoidsafety of charging port
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The cooling system is divided into two separate circuits: a first cooling circuit for low-voltage components and a second cooling circuit for high-voltage components. This segmentation allows independent temperature control for different components, enabling effective cooling of charging components during fast charging without compromising other vehicle systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A dielectric coolant is introduced as an intermediary substance in the second cooling circuit. This coolant provides both cooling functionality and electrical insulation, allowing direct contact with high-voltage charging components while preventing electrical hazards. The dielectric coolant enables efficient heat transfer from charging components without compromising safety.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Stress or pressure

If contact pins are made loose to accommodate thermal expansion, then thermal stress is reduced, but contact resistance increases

Engineering Contradiction:
Improvethermal stress on contact pinsVSAvoidcontact resistance
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The cooling system actively removes heat from charging components before thermal expansion can significantly increase contact resistance. By maintaining lower operating temperatures through the second cooling circuit, the contact pins remain closer to their intended position, minimizing play and maintaining low contact resistance throughout the charging process.

Inventive Principle:
Principle #10Preliminary action

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

Enables efficient cooling of energy storage devices and other high-voltage components during fast charging and high-power operation, reducing thermal expansion and contact resistance, and ensuring safe, cost-effective operation by separating fluid and electrical connections.

Implementation Method 1

the at least one second coolant is designed for temperature control of high-voltage vehicle components

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

Temperatures well above 90 °C cause thermal expansion of the contact pins and thus increased contact resistance

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

the at least one first cooling circuit, the at least one second cooling circuit, and a refrigerant circuit are coupled or connected to each other for heat exchange

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4678462A1Cooling system for cooling vehicle components of a battery- electrically operated vehicle, and vehicle having at least one such cooling system
Publication Date: 2026.01.14 VOSS AUTOMOTIVE GMBH
  • EP4678462A1 patent drawingFigure 1~2
  • EP4678462A1 patent drawingFigure 3~4
  • EP4678462A1 patent drawingFigure 5~6

AI summary

In a cooling system (1) for cooling vehicle components, in particular an energy storage device (30), of a battery-electric vehicle, wherein the cooling system (1) comprises at least a first cooling circuit (10) with at least a first coolant and at least a second cooling circuit (20) with at least a second coolant, and wherein the at least one second coolant is designed for temperature control of high-voltage vehicle components, the at least one second cooling circuit (20) serves to temperature control at least two vehicle components (30, 31, 32, 33, 34, 38), one of which is the energy storage device (30) of the battery-electric vehicle, and/or the at least one first cooling circuit (10), the at least one second cooling circuit (20) and a refrigerant circuit (50) are coupled or connected to each other for heat exchange.