Ionic Liquid Battery Extinguishing for Thermal Runaway Discharge

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Solution Overview

Problem

Conventional methods for extinguishing electrochemical generators like Li-ion batteries during thermal runaway, such as flooding with water, can lead to the production of dihydrogen gas, which may ignite, and react violently with active materials, posing explosion risks and increasing safety concerns as manufacturers use more exothermic materials.

Innovation Solution

The method involves using an ionic liquid solution that covers the electrochemical generator, containing an active species with extinguishing and flame retardant properties, which avoids the generation of oxygen and hydrogen, providing effective cooling and discharge without risking inflammation or explosion, and includes a redox species to safely unload the generator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If water-based extinguishing agent is used to cool and discharge the electrochemical generator, then cooling efficiency and electrical discharge are improved, but hydrogen gas production and explosion risk increase

Engineering Contradiction:
Improvecooling efficiencyVSAvoidhydrogen gas production and explosion risk
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameter of the extinguishing agent from water-based to ionic liquid-based. This parameter change maintains the cooling capability while eliminating hydrogen gas production, as ionic liquids do not undergo the same electrochemical reactions that produce hydrogen when in contact with battery materials.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs an ionic liquid solution that can be used as a disposable extinguishing medium. The solution is applied to the battery, performs its cooling and discharge function, and then can be safely disposed of without concern for residual hydrogen generation or long-term stability issues.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Use of energy by moving object

If water is sprayed on the electrochemical generator during thermal runaway, then the electrical energy is discharged through conductive aqueous medium, but violent reaction with active materials produces intense heat and hydrogen gas

Engineering Contradiction:
Improveelectrical energy dischargeVSAvoidintense heat and hydrogen gas from violent reaction
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical properties of the liquid medium from water to ionic liquid. This parameter change allows the medium to conduct electricity for discharge while being chemically inert toward the battery's active materials, preventing violent reactions and hydrogen gas generation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The ionic liquid acts as an intermediary substance that facilitates electrical discharge without directly reacting with the battery components. It provides the conductive pathway needed for energy dissipation while remaining chemically stable and non-reactive with the active materials.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If manufacturers increase battery energy using more exothermic materials, then energy density is improved, but thermal runaway risk and fire intensity increase

Engineering Contradiction:
Improveenergy densityVSAvoidthermal runaway risk and fire intensity
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful exothermic nature of the battery materials into a manageable condition by using an ionic liquid extinguishing agent that can safely handle high-temperature reactions. The ionic liquid's high thermal stability allows it to absorb and dissipate the intense heat from exothermic materials without itself decomposing or contributing to fire.

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

Solution Approach 2:

The ionic liquid creates a chemically inert environment around the high-energy battery materials. This inert atmosphere prevents unwanted chemical reactions between the exothermic materials and ambient air or moisture, thereby reducing thermal runaway risk while allowing the battery to maintain its high energy density.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

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

This approach prevents the formation of explosive air/vapor mixtures, ensures safe cooling and discharge, and is economically viable as the ionic liquid solution is non-volatile and chemically stable at high temperatures, reducing the risk of thermal runaway and maintaining safety even with structural deterioration.

Implementation Method 1

the electrochemical generator is cooled and/or discharged with a solution containing an ionic liquid

Methodology Applied
Scientific EffectThermal energy absorption: Heat Sink

Implementation Method 2

the ionic liquid solution comprising an ionic liquid and an active species having extinguishing and/or flame-retardant properties

Methodology Applied
Scientific EffectRedox reactions: Redox Reactions

Data Source

PatentEP3970225B1Method for extinguishing an electrochemical generator in the event of of thermal runaway
Publication Date: 2023.09.13 COMMISSARIAT A LENERGIE ATOMIQUE & AUX ENERGIESALTERNATIVES FR
  • EP3970225B1 patent drawingFigure 1~2
  • EP3970225B1 patent drawingFigure 3~4

AI summary

Disclosed is a method for extinguishing an electrochemical generator (10), in particular in the event of thermal runaway, the electrochemical generator (10) comprising a first electrode and a second electrode, the first electrode being connected to a first terminal (22) and the second electrode being connected to a second terminal (32) or to the ground of the electrochemical generator, the method comprising a step in which the electrochemical generator (10) is covered by an ionic liquid solution (100), the ionic liquid solution (100) continuously covering the electrochemical generator (10) from the first terminal (22) to the second terminal (32) or from the first terminal (22) to the ground, the ionic liquid solution comprising an ionic liquid and an active species having flame-extinguishing and/or flame-retardant properties.