Flexible Graphite Fire Retardancy Element for Battery Packs

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Solution Overview

Problem

Lithium ion batteries pose a fire and explosion risk due to their flammable electrolytes, which can lead to hazardous incidents in devices such as electric vehicles and consumer electronics.

Innovation Solution

A battery pack design incorporating a fire retardancy element with flexible graphite outer layers and a foam core, where the flexible graphite layers are separated by a fire retardant material like expandable graphite, to reduce fire propagation and enhance safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If lithium ion batteries are used to generate large amounts of energy, then energy output is improved, but fire and explosion risk increases

Engineering Contradiction:

Improveenergy outputVSAvoidfire and explosion risk

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

A fire retardancy element is introduced as an intermediary component between battery cells to prevent fire propagation. This element includes flexible graphite outer layers and a foam core with fire retardant materials, acting as a barrier that blocks the spread of flames and hot gases while allowing the battery system to maintain its high energy output capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The fire retardancy element utilizes composite material construction combining flexible graphite sheets with foam core materials containing fire retardant additives. This composite structure provides both mechanical integrity and fire resistance, creating a multi-functional barrier that addresses the fire risk without compromising the battery's energy generation capability

Inventive Principle:

Principle #40Composite materials

2Reliability

If fire retardant materials are added to the battery pack, then fire resistance is improved, but device complexity increases

Engineering Contradiction:

Improvefire resistanceVSAvoidstructural complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The fire retardancy element is designed to perform multiple functions simultaneously: it acts as a fire barrier, provides thermal insulation, and serves as a structural separator between battery cells. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving improved fire resistance

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The use of flexible graphite outer layers provides a thin-film solution that delivers effective fire protection without requiring thick or bulky materials. This approach maintains a compact battery pack design and avoids excessive structural complexity while ensuring reliable fire resistance

Inventive Principle:

Principle #30Flexible shells and thin films

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 inhibits fire propagation, providing up to 50 minutes of fire resistance at temperatures up to 350°C, significantly reducing the risk of battery-related fires and explosions.

Implementation Method 1

1st and 2nd flexible graphite sheets, each flexible graphite sheet having a thickness of at least 0.25 mm and a thermal conductivity of at least 300 W/mK

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The foam core may include one or more fire retardant elements. One such fire retardant element may include an intumescent element such as expandable graphite

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS20230253673A1A shielding article

Publication Date: 2023.08.10 NEOGRAF SOLUTIONS LLC

AI summary

Shielding articles are disclosed. One shielding article includes a fire retardancy element/fire propagation reduction element, which includes a pair of flexible graphite outer layers and a core, where the flexible graphite outer layers are on opposing sides of the core. The core may include one or more fire retardant elements or insulation materials. Also disclosed are battery packs that include the shielding articles. The shielding articles can be applied in any system that reduced fire propagation would be desirable.