Battery Assembly Thermal Delay Structure for Runaway Containment

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Solution Overview

Problem

Lithium secondary batteries are prone to thermal runaway, leading to fires that can spread through empty spaces in battery modules, posing a significant safety risk, especially in electric vehicles.

Innovation Solution

Incorporating a thermal delay assembly with a fire-extinguishing member and a housing member into the void between busbar assemblies and cell tabs, which generates fire-extinguishing gas at a predetermined temperature and includes a fire-resistant material to contain and block heat and flames.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If empty spaces are left in battery modules for energy source accommodation, then battery cell placement flexibility is improved, but flame spread risk increases

Engineering Contradiction:

Improvebattery cell placement flexibilityVSAvoidflame spread risk

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

A thermal delay assembly is introduced as an intermediary substance filling the empty spaces between battery cells. This assembly includes fire-extinguishing members containing fire-retardant materials that act as mediators to prevent direct flame propagation through empty spaces, while still allowing the battery module structure to accommodate cells flexibly.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The fire-extinguishing members in the thermal delay assembly create an inert or non-combustible environment in the empty spaces between battery cells. By filling these spaces with fire-retardant materials, the atmosphere in previously empty spaces becomes incapable of supporting flame propagation, thus preventing fire spread while maintaining structural flexibility.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Reliability

If thermal delay assembly is inserted into void between busbar assembly and cell tabs, then fire resistance is improved, but assembly process complexity increases

Engineering Contradiction:

Improvefire resistanceVSAvoidassembly process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The thermal delay assembly is designed to be pre-formed with specific shapes and sizes that match the void spaces between busbar assemblies and cell tabs. This preliminary preparation allows the assembly to be easily inserted into predetermined locations during the battery module assembly process, improving fire resistance without significantly complicating the overall assembly procedure.

Inventive Principle:

Principle #10Preliminary action

3Object-affected harmful factors

If fire-extinguishing member generates gas at high temperature, then fire suppression effectiveness is improved, but thermal stability requirements increase

Engineering Contradiction:

Improvefire suppression effectivenessVSAvoidthermal stability requirement

Core Design Contradiction:

Object-affected harmful factorsVSTemperature

Solution Approach 1:

The fire-extinguishing members are designed to undergo phase transitions at specific temperature thresholds. When exposed to fire temperatures, these materials transition from solid to gas phase, releasing fire-extinguishing gases that suppress flames. The phase transition occurs at controlled temperatures to ensure effectiveness while managing thermal stability requirements of the overall battery module.

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 assembly effectively prevents the spread of high-temperature gas and flames, enhancing the thermal stability and safety of battery assemblies by mitigating thermal runaway events.

Implementation Method 1

the fire-extinguishing member may comprise one or more of a potassium compound, a phosphoric acid compound, or any combination thereof, which are pyrolyzed at the first temperature to generate the fire-extinguishing gas

Methodology Applied

Scientific EffectPyrolysis: Pyrolysis

Implementation Method 2

the housing member may begin to melt at a predetermined second temperature

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 3

provides to the stability of the battery assembly can be improved by increasing heat resistance or fire resistance

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS20250349957A1Battery assemble and assembling method of the same

Publication Date: 2025.11.13 SK ON CO LTD

AI summary

The present disclosure relates to a battery assembly comprising: a plurality of battery cells stacked and arranged in a predetermined stacking direction; an accommodation case housing the plurality of battery cells; an insertion space formed between the plurality of battery cells and the accommodation case along the stacking direction; and a thermal delay assembly located in the insertion space, the thermal delay assembly including: a fire-extinguishing member; and a columnar housing member housing the fire-extinguishing members therein and extending along a height direction of the accommodation case; and an assembly method thereof.