Battery Cell Assembly Bonding Structure for Thermal Runaway Venting

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Solution Overview

Problem

The rapid rise in temperature and potential for thermal runaway in battery modules due to inadequate heat dissipation leads to accelerated deterioration and increased risk of explosion or ignition, especially in high-temperature conditions and when thermal runaway occurs in one battery module, it can propagate to neighboring modules.

Innovation Solution

A cell assembly design featuring a first bonding body made of polymer foam with lower hardness and a second bonding body made of synthetic resin, where the polymer foam foams under heat to induce a vent and prevent flame propagation by applying to the electrode leads' protruding portions, while the resin contacts non-protruding portions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple battery cells are densely stacked to increase power output, then capacity and power output are improved, but heat dissipation becomes difficult and temperature rises rapidly

Engineering Contradiction:
Improvepower outputVSAvoidtemperature rise
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The bonding bodies are divided into multiple separate components (first bonding body and second bonding body) that are disposed between individual battery cells. This segmentation allows each bonding body to independently manage thermal conditions for adjacent cells, creating thermal zones that prevent rapid temperature propagation while maintaining dense cell stacking for high power output.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bonding bodies serve as intermediary elements between adjacent battery cells. These intermediaries provide thermal isolation and heat dissipation pathways, mediating the thermal interaction between cells to prevent rapid temperature rise while allowing dense stacking for high power output.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If bonding bodies with high hardness are used to secure battery cells, then structural stability is improved, but thermal propagation is accelerated due to efficient heat conduction

Engineering Contradiction:
Improvestructural stabilityVSAvoidthermal propagation
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The bonding bodies are constructed from composite materials that combine structural stability with thermal isolation properties. These composite materials provide the mechanical strength needed to secure battery cells while simultaneously resisting thermal propagation, resolving the contradiction between stability and thermal protection.

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If bonding bodies with low hardness are used to provide thermal isolation, then thermal propagation is delayed, but structural support and cell securing are insufficient

Engineering Contradiction:
Improvethermal propagationVSAvoidstructural support
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The bonding structure is segmented into multiple bonding bodies distributed between different battery cells. Each bonding body can be optimized for its specific function, and collectively they provide both thermal isolation and structural support, resolving the contradiction between thermal protection and mechanical strength.

Inventive Principle:
Principle #1Segmentation

4Ease of manufacture

If a single uniform bonding material is used for all battery cells, then manufacturing simplicity is maintained, but thermal isolation effectiveness is reduced due to lack of optimization for different positions

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidthermal isolation effectiveness
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

Different bonding bodies are assigned different properties or configurations based on their local requirements. This local quality optimization allows each bonding body to be tailored for maximum thermal isolation effectiveness at its specific position, while the overall multi-component structure can still be manufactured using standardized processes.

Inventive Principle:
Principle #3Local quality

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 design effectively delays and prevents flame propagation between battery cells by inducing a vent at the electrode lead protruding portions, maintaining the integrity of the cell assembly and minimizing the risk of explosion.

Implementation Method 1

the polymer foam foams under heat to induce a vent and prevent flame propagation

Methodology Applied
Scientific EffectFoaming under heat: Intumescent Materials

Implementation Method 2

the polymer foam foams under heat to induce a vent

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4708502A1Cell assembly, battery module including same, and method for manufacturing cell assembly
Publication Date: 2026.03.11 LG ENERGY SOLUTION LTD
  • EP4708502A1 patent drawingFigure 1
  • EP4708502A1 patent drawingFigure 2
  • EP4708502A1 patent drawingFigure 3

AI summary

A cell assembly according to an embodiment of the present disclosure may include a plurality of battery cells stacked on each other and each having an electrode lead; a first bonding body formed to contact the electrode leads of the plurality of battery cells; and a second bonding body formed to contact the plurality of battery cells and non-overlapped with the first bonding body, wherein the first bonding body may be made of a material having lower hardness than the second bonding body.