Lithium Battery Heat-Resistant Spacer Layer for Thermal Runaway Prevention

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Solution Overview

Problem

Lithium metal batteries face issues with dendrite formation leading to internal shorting and thermal runaway, while lithium-ion batteries have safety concerns due to flammable solvents and low energy density, hindering their widespread commercialization for electric vehicles and portable devices.

Innovation Solution

A lithium secondary battery design incorporating a cathode-protecting or anode-protecting layer made of a lithium ion-conducting polymer matrix with inorganic material particles, which prevents massive internal shorting by maintaining a gap between electrodes even when the separator fails, and is used in conjunction with a non-flammable electrolyte to enhance safety and energy density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If lithium metal is used as anode active material to achieve high energy density, then energy density is improved, but dendrite formation occurs leading to internal shorting and thermal runaway

Engineering Contradiction:

Improveenergy densityVSAvoidsafety

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

A protective layer comprising a lithium ion-conducting polymer matrix and inorganic material particles is introduced as an intermediary between the lithium metal anode and the electrolyte. This protective layer mediates the interaction by allowing lithium ion transport while preventing direct contact between the lithium metal and electrolyte, thereby eliminating dendrite formation and thermal runaway risks while maintaining high energy density benefits

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If flammable organic liquid solvents are used in electrolyte to achieve good ion conductivity, then ion conductivity is improved, but thermal runaway and explosion risks increase

Engineering Contradiction:

Improveion conductivityVSAvoidflammability

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention replaces flammable organic liquid solvents with water as the electrolyte solvent. By combining water with the protective layer containing lithium ion-conducting polymer and inorganic particles, the system achieves both safety (non-flammability) and good ion conductivity, converting the harmful flammability characteristic into a safe water-based system

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If carbonaceous materials are used as anode to prevent dendrites, then safety is improved, but energy density decreases significantly

Engineering Contradiction:

ImprovesafetyVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

Instead of using carbonaceous materials that prevent dendrites but reduce energy density, the invention inverts the approach by using lithium metal (which provides high energy density) but protecting it with a protective layer that prevents dendrite formation. This allows the system to achieve both high safety and high energy density simultaneously

Inventive Principle:

Principle #13The other way round (Inversion)

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 prevents thermal runaway and explosion, achieving high energy density and long cycle life, making lithium batteries safer and more suitable for electric vehicles and portable devices.

Implementation Method 1

a lithium ion-conducting polymer matrix with inorganic material particles

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

particles of a thermally stable material having a heat-induced degradation temperature or melting point higher than 400 C. The heat-resistant spacer layer acts to space apart the anode and the cathode when the porous separator fails

Methodology Applied

Scientific EffectThermal expansion resistance: Thermal Expansion

Data Source

PatentUS20190372174A1Method of improving fire-resistance of a lithium battery

Publication Date: 2019.12.05 HONEYCOMB BATTERY CO

AI summary

A method of improving fire resistance of a lithium battery, the method comprising disposing a heat-resistant spacer layer between a porous separator and a cathode layer or anode layer, wherein the heat-resistant spacer layer contains a distribution of particles of a thermally stable material having a heat-induced degradation temperature or melting point higher than 400° C. (up to 3,500° C.) and wherein the heat-resistant spacer layer acts to space apart the anode and the cathode when the porous separator of the battery fails. Such a heat-resistant spacer layer prevents massive internal shorting from occurring when the porous separator gets melted, contracted, or collapsed under extreme temperature conditions induced by, for instance, dendrite or nail penetration.