Battery Module Absorption Barrier for Thermal Runaway Isolation

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Solution Overview

Problem

Conventional battery packs face risks of secondary ignition and explosion due to heat transfer from one cell assembly to adjacent assemblies during thermal runaway, and there is a need to prevent such propagation and reduce side reactions.

Innovation Solution

A battery module with an absorption member made of synthetic fiber that absorbs fire extinguishing liquid, forming an insulation barrier between cell assemblies, and a pressing member to prevent expansion, combined with a fire extinguishing unit that supplies liquid to the module upon thermal runaway.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional battery packs use multiple battery modules without additional safety structures, then device complexity is reduced and manufacturing cost is lowered, but heat transfer occurs during thermal runaway causing secondary ignition or explosion

Engineering Contradiction:
Improveprevention of secondary ignitionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

An absorption member is introduced as an intermediary component positioned between adjacent battery modules. This member absorbs fire extinguishing liquid and forms a barrier that prevents heat transfer during thermal runaway, thereby preventing secondary ignition without requiring complex active monitoring or control systems

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The absorption member is pre-filled with fire extinguishing liquid before thermal runaway occurs. When thermal runaway happens, the liquid is already in place to absorb heat and suppress flames, enabling immediate response without requiring active detection or deployment mechanisms

Inventive Principle:
Principle #10Preliminary action

2Reliability

If fire extinguishing liquid is supplied into the battery module during thermal runaway, then heat transfer is blocked and secondary ignition is prevented, but the absorption member requires sufficient liquid absorption capacity

Engineering Contradiction:
Improveheat blocking capabilityVSAvoidfire extinguishing liquid volume
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The absorption member utilizes porous material structure that can absorb and retain large volumes of fire extinguishing liquid within its internal pore network. This porous structure enables the member to hold sufficient extinguishing liquid to block heat transfer effectively without requiring excessive external liquid reservoirs

Inventive Principle:
Principle #31Porous materials

3Duration of action of stationary object

If the absorption member is positioned between pressing plates, then the cell assembly expansion is prevented and service life is increased, but the absorption member may be compressed reducing its liquid absorption capability

Engineering Contradiction:
Improveservice lifeVSAvoidliquid absorption capacity
Core Design Contradiction:
Duration of action of stationary objectVSQuantity of substance

Solution Approach 1:

The pressing plates apply sufficient compression to prevent cell assembly expansion and maintain structural stability, while the absorption member is designed with excess absorption capacity to maintain adequate liquid retention even under compression. The compression is optimized to be just enough to prevent expansion without completely eliminating absorption capability

Inventive Principle:
Principle #16Partial or excessive 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

The solution effectively blocks heat transfer and prevents thermal runaway propagation, enhancing safety by absorbing fire extinguishing liquid and stabilizing cell assemblies, thereby increasing the service life of the battery module.

Implementation Method 1

an absorption member interposed between the at least two cell assemblies and configured to absorb the fire extinguishing liquid when contacting the fire extinguishing liquid supplied into the module housing

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

the absorption member may include a synthetic fiber configured to absorb the fire extinguishing liquid

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 3

the absorption member may form an insulation barrier capable of blocking the transfer of heat between the cell assemblies

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4044349B1Battery module comprising absorption member, battery rack comprising same, and power storage system
Publication Date: 2025.11.12 LG ENERGY SOLUTION LTD
  • EP4044349B1 patent drawingFigure 1
  • EP4044349B1 patent drawingFigure 2
  • EP4044349B1 patent drawingFigure 3~4

AI summary

Disclosed is a battery pack that reduces the risk of secondary ignition or explosion. The battery module includes at least two cell assemblies, each having a plurality of secondary batteries; a module housing having an inner space formed to accommodate the at least two cell assemblies therein; and an absorption member interposed between the at least two cell assemblies and configured to absorb a fire extinguishing liquid when contacting the fire extinguishing liquid supplied into the module housing.