Direct Cooling Cable Using Conductive Fluid for EV Fast Charging

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Solution Overview

Problem

Charging cables for electric vehicles generate excessive heat due to high current flow, leading to potential damage and handling difficulties, and traditional cooling methods using non-conductive fluids are limited by fluid properties and result in bulky designs.

Innovation Solution

A direct cooling system using a water-based conductive fluid with ethylene glycol and water mixture, combined with a feedback loop and ion filters, to manage electrical resistance and mitigate arc and hydrogen generation, allowing for thinner and more flexible cables.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If larger conductors are used to match higher current draws, then heat generation is managed, but cable bulk, cost, and handling difficulty increase

Engineering Contradiction:
Improveheat generationVSAvoidcable bulk
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The patent introduces dielectric fluid as an intermediary cooling medium that flows through channels surrounding the conductors. This fluid acts as a heat transfer intermediary, absorbing heat from the conductors and carrying it away, thereby managing heat generation without requiring larger conductor cross-sections, thus avoiding increased cable bulk

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs hydraulic cooling by circulating dielectric fluid through dedicated cooling channels. This hydraulic system efficiently removes heat from high-current conductors through forced convection, enabling the cable to handle higher currents without increasing conductor size and cable bulk

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Temperature

If traditional non-conductive cooling fluids are used, then heat dissipation is achieved, but fluid properties limit cooling effectiveness and increase cable bulk

Engineering Contradiction:
Improveheat dissipationVSAvoidcable design complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent changes the key parameter of cooling fluid from non-conductive to conductive dielectric fluid. This parameter change enables more effective heat dissipation through enhanced thermal conductivity while maintaining electrical insulation properties, thereby improving cooling effectiveness without requiring bulkier cable designs

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite structures combining conductors, dielectric fluid, and cooling channels. The dielectric fluid itself acts as a functional composite material that provides both cooling and electrical insulation, eliminating the need for separate insulation layers and reducing overall cable complexity

Inventive Principle:
Principle #40Composite materials

3Temperature

If water-based conductive fluid is used for direct cooling, then heat dissipation efficiency increases, but risk of arc and hydrogen generation increases

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidarc and hydrogen generation risk
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potential harm of using conductive fluid (arc and hydrogen generation risk) into a benefit by carefully selecting dielectric fluids with appropriate properties. The system exploits the high thermal conductivity of conductive fluids for superior cooling while the feedback loop detects and mitigates any harmful effects, thereby achieving efficient heat dissipation without compromising safety

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

Solution Approach 2:

The patent incorporates a feedback loop with sensors that continuously monitor the cooling fluid for signs of arcing, hydrogen generation, or other harmful conditions. When anomalies are detected, the system responds by adjusting operating parameters or alerting operators, thereby preventing harmful effects while maintaining efficient heat dissipation

Inventive Principle:
Principle #23Feedback

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 system effectively dissipates heat while minimizing the risk of arc and hydrogen generation, enabling higher current capacity without increasing cable bulk, thus enhancing safety and usability.

Implementation Method 1

A direct cooling system using a water-based conductive fluid with ethylene glycol and water mixture... effectively dissipates heat

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

A direct cooling system using a water-based conductive fluid... combined with a feedback loop... to manage electrical resistance and mitigate arc and hydrogen generation

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

combined with a feedback loop and ion filters, to manage electrical resistance and mitigate arc and hydrogen generation

Methodology Applied
Scientific EffectIon filtration: Ion Exchange

Data Source

PatentEP4320007B1Charging system with cooling system
Publication Date: 2026.03.25 TESLA INC
  • EP4320007B1 patent drawingFigure 1
  • EP4320007B1 patent drawingFigure 2
  • EP4320007B1 patent drawingFigure 3

AI summary

A direct cooling method and system in charging system utilizing a water-based conductive fluid. The charging system includes a conductive fluid reservoir that provides conductive fluid to charging system components. The charging system further defines conductive fluid return paths for the conductive fluid. The length of a fluid path is specified to exceed a minimal resistance threshold based on the product of the resistivity and return path length. The system can include the incorporation of feedback loop into the charging system that can measure the electrical resistance of the conductive fluid.