Encapsulated Flame-Retardant Additives for Li-Ion Thermal Runaway

Solution Overview

Problem

Lithium-ion batteries face challenges with electrolyte additives that provide thermal runaway resistance but often result in poor cell performance and increased cell resistance, necessitating a non-invasive solution that balances non-flammability and high performance.

Innovation Solution

A thermal runaway-inhibiting composition comprising particles with an encapsulant melting at temperatures greater than 70°C, encapsulating a flame retardant additive, which can be introduced into the electrolytic solution or electrode, releasing a passivating agent at high temperatures to prevent further thermal reactions without interfering with battery function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrolyte additives such as phosphates are used to improve thermal runaway resistance, then thermal runaway resistance is improved, but cell performance deteriorates and cell resistance increases

Engineering Contradiction:

Improvethermal runaway resistanceVSAvoidcell performance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The flame retardant additive is pre-encapsulated within a shell that remains intact during normal battery operation. The encapsulation protects the additive from interfering with battery performance while positioning it to activate automatically when thermal runaway conditions occur, releasing the additive only when needed to suppress thermal runaway

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the release parameter of the flame retardant additive by using temperature-dependent shell breakdown. The shell is designed to remain stable at normal operating temperatures but decompose or melt at elevated temperatures (above 100°C), thereby controlling when the additive becomes active based on temperature conditions

Inventive Principle:

Principle #35Parameter changes

2Reliability

If electrolyte additives such as phosphates are used to improve thermal runaway resistance, then thermal runaway resistance is improved, but cell resistance increases

Engineering Contradiction:

Improvethermal runaway resistanceVSAvoidcell resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The flame retardant additive is pre-encapsulated within a shell that remains intact during normal battery operation. The encapsulation protects the additive from interfering with battery performance while positioning it to activate automatically when thermal runaway conditions occur, releasing the additive only when needed to suppress thermal runaway

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The encapsulation shell acts as an intermediary between the flame retardant additive and the electrolyte. It prevents direct contact between the additive and electrolyte during normal operation, avoiding increased cell resistance, while allowing the additive to be released when thermal runaway conditions occur

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If a non-invasive solution is used to maintain high performance, then cell performance is maintained, but thermal runaway resistance is reduced

Engineering Contradiction:

Improvecell performanceVSAvoidthermal runaway resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The flame retardant additive is pre-encapsulated within a shell that remains intact during normal battery operation. The encapsulation protects the additive from interfering with battery performance while positioning it to activate automatically when thermal runaway conditions occur, releasing the additive only when needed to suppress thermal runaway

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the release parameter of the flame retardant additive by using temperature-dependent shell breakdown. The shell is designed to remain stable at normal operating temperatures but decompose or melt at elevated temperatures (above 100°C), thereby controlling when the additive becomes active based on temperature conditions

Inventive Principle:

Principle #35Parameter changes

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 thermal runaway in lithium-ion batteries by releasing a passivating agent at high temperatures, maintaining battery performance and safety while preventing flammability, thus addressing the limitations of existing additives.

Implementation Method 1

the encapsulant can melt or dissolve and release a quick passivating agent that can stifle further thermal reaction

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS20240030500A1Slow-release additive for abuse tolerant lithium-ion battery cell

Publication Date: 2024.01.25 FORD GLOBAL TECH LLC

AI summary

A thermal runaway inhibiting composition for a battery includes a plurality of particles. Each particle includes an encapsulant configured to melt at a temperature greater than 70° C. and a flame retardant additive encapsulated by the encapsulant. Characteristically, the plurality of particles having a size distribution to inhibit thermal runaway when the thermal runaway-inhibiting composition is included in a battery cell.