Flame-Retardant Electrode Layering for Battery Thermal Runaway

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Solution Overview

Problem

Lithium secondary batteries are prone to external impacts and internal deterioration, leading to thermal runaway and ignition due to heat transfer among battery cells, which can cause chain-like exothermic reactions and spread fires throughout the battery pack.

Innovation Solution

An electrode design with a functional layer containing a flame-retardant binder having a limiting oxygen index of 30% or more is interposed between the current collector and the electrode active material layer, using materials like phenolic resin and polybenzoxazole resin to block heat transfer and thermal runaway.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional electrode structure without flame-retardant layer is used, then manufacturing simplicity is maintained, but thermal runaway prevention capability is insufficient

Engineering Contradiction:

Improvethermal runaway preventionVSAvoidelectrode structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The electrode is segmented into multiple functional layers: current collector, flame-retardant binder layer, and active material layer. This segmentation allows the flame-retardant layer to independently perform thermal protection while other layers handle electrochemical functions, resolving the contradiction between reliability improvement and structural complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flame-retardant binder layer is pre-installed between the current collector and active material layer before battery operation. This preliminary protective action ensures that thermal runaway is prevented before it can occur, adding reliability without requiring complex active control systems.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If flame-retardant electrolytes are used to prevent thermal runaway, then thermal safety is improved, but cost increases and side reactions are suppressed less effectively

Engineering Contradiction:

Improvethermal safetyVSAvoidcost and processing

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The flame-retardant function is extracted from the electrolyte and relocated to the electrode structure itself. By placing the flame-retardant binder layer within the electrode, the electrolyte can remain simple and cost-effective while the electrode provides thermal protection, reducing overall manufacturing cost and simplifying processing.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The flame-retardant binder layer acts as an intermediary between the current collector and active material, providing thermal protection at the source of heat generation. This intermediary approach is more effective than adding flame retardants to the electrolyte, as it directly addresses thermal runaway at the electrode level while being more cost-effective.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the limiting oxygen index of the binder is increased to 30% or more, then combustion resistance is improved, but material selection becomes more restricted

Engineering Contradiction:

Improvecombustion resistanceVSAvoidmaterial selection

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The flame-retardant binder is used specifically in the layer where thermal protection is most critical - between the current collector and active material. This localized application with high combustion resistance (LOI ≥ 30%) optimizes protection where needed most, while allowing other electrode components to use more versatile materials.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The electrode uses a composite structure combining the flame-retardant binder layer with conventional electrode materials. This composite approach allows the system to achieve high combustion resistance through the specialized binder layer while maintaining the electrochemical performance of standard active materials, balancing safety requirements with material versatility.

Inventive Principle:

Principle #40Composite materials

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 electrode design effectively prevents self-combustion and delays thermal runaway, maintaining battery characteristics while being cost-effective and easier to apply, compared to flame-retardant electrolytes, and suppresses side reactions.

Implementation Method 1

the functional layer includes a flame-retardant binder having a limiting oxygen index of 30% or more

Methodology Applied

Scientific EffectFlame retardation:

Implementation Method 2

interposes a functional layer... between a current collector and an electrode active material layer... to block heat transfer and thermal runaway

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4697445A1Electrode, and lithium secondary battery and battery pack comprising same

Publication Date: 2026.02.18 LG ENERGY SOLUTION LTD

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AI summary

The present specification relates to an electrode including an electrode current collector layer; an electrode active material layer; and a functional layer interposed between the electrode current collector layer and the electrode active material layer, in which the functional layer includes a specific type of flameretardant binder and has a limiting oxygen index of 30% or more, and also relates to a lithium secondary battery including the same and a battery pack. The electrode according to the exemplary embodiment can prevent thermal runaway while ensuring battery characteristics.