Battery Module Nebulizer for Thermal Runaway Mitigation

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Solution Overview

Problem

Conventional battery pack cooling solutions fail to effectively mitigate thermal runaway in lithium-ion batteries, allowing energy propagation to other accumulators, which can lead to further thermal runaway and safety issues, particularly in public applications where misuse and poor management are common.

Innovation Solution

A battery module incorporating a nebulizer device with a reservoir, piezoelectric element, and temperature sensor that atomizes a liquid into microdroplets when a thermal runaway threshold is reached, absorbing energy and preventing its transmission to other accumulators, thereby controlling temperature and preventing secondary runaways.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional cooling solutions are used, then the battery module can maintain basic cooling function, but the energy of thermal runaway propagates to other accumulators causing safety issues

Engineering Contradiction:
Improvethermal runaway preventionVSAvoidthermal energy propagation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by pre-positioning a fire suppressant reservoir and nebulizing device within the battery module structure. The device is prepared in advance with suppressant material ready for rapid deployment when thermal runaway is detected, eliminating the need for complex active cooling systems while effectively preventing thermal energy propagation to adjacent accumulators.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediary approach by introducing a fire suppressant substance as a mediator between the thermal runaway source and adjacent accumulators. The suppressant material, when nebulized, forms a barrier that intercepts and absorbs thermal energy, preventing its propagation to other battery cells without requiring direct contact or complex thermal management systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If advanced thermal runaway mitigation systems are implemented, then safety is improved, but device complexity and weight increase

Engineering Contradiction:
Improvethermal runaway mitigationVSAvoidcooling system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential safety function from complex active cooling systems by isolating and implementing only the critical components: a fire suppressant reservoir, a simple nebulizing mechanism, and temperature sensing. This extraction eliminates unnecessary complexity while maintaining effective thermal runaway mitigation through passive suppressant deployment.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs disposable short-living objects by using a single-use fire suppressant reservoir that is depleted after one thermal runaway event. The reservoir is designed for simple replacement rather than complex maintenance or active control systems, reducing overall device complexity while providing reliable safety protection.

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

3Temperature

If active cooling systems are used, then temperature control is improved, but the system fails to prevent thermal runaway propagation

Engineering Contradiction:
Improvetemperature controlVSAvoidthermal runaway containment
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent converts harm into benefit by using the thermal runaway event itself as the trigger for suppressant deployment. The temperature rise that indicates thermal runaway also activates the nebulizing device, automatically deploying the fire suppressant precisely when needed. This transforms the harmful thermal signal into a beneficial activation mechanism, eliminating the need for separate active cooling control systems.

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

Solution Approach 2:

The patent utilizes phase transitions by nebulizing the fire suppressant from liquid to aerosol form, dramatically increasing its surface area and heat absorption capacity. This phase transition enables the suppressant to rapidly absorb thermal energy from the runaway cell and adjacent cells, providing effective thermal containment without requiring complex active cooling infrastructure.

Inventive Principle:
Principle #36Phase transitions

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 a lightweight, easy-to-implement safety mechanism that effectively limits thermal runaway propagation within the module, maintaining pack performance and safety without significant weight or size penalties, suitable for on-board applications.

Implementation Method 1

at least one piezoelectric element arranged in contact with a surface of the reservoir, the piezoelectric element(s) being suitable for vibrating the surface of the reservoir when supplied with electricity

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the latter(s) cause(s) to vibrate the surface of the reservoir in order to nebulize the liquid in microdroplets projected into the module... absorbing energy and preventing its transmission to other accumulators

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4011676A1Battery module with a plurality of electrochemical accumulators, comprising a nebuliser device for spraying microdroplets in the event of thermal runaway of at least one of the accumulators
Publication Date: 2022.06.15 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4011676A1 patent drawingFigure 1~3
  • EP4011676A1 patent drawingFigure 4~5
  • EP4011676A1 patent drawingFigure 6

AI summary

The invention essentially consists of integrating within a battery module (M) a nebulizer (10) configured to atomize a liquid, preferably water, contained in a reservoir beyond a threshold temperature characteristic of a thermal runaway, the microdroplets thus created being projected within the module to absorb the energy created by the thermal runaway.