Gel Polymer Electrolyte for Lithium Battery High-Temperature Stability

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Solution Overview

Problem

Lithium secondary batteries face issues with electrode degradation, volatility of organic solvents, and safety concerns due to gas generation, leading to performance decline and safety risks, especially at high temperatures, which are exacerbated by the use of liquid electrolytes.

Innovation Solution

A gel polymer electrolyte composition is developed, comprising a liquid electrolyte solvent, a lithium salt, a polymerization initiator, and a mixed compound of an amine-based compound with polyethylene glycol and an epoxy-based compound, which enhances ion mobility and stability, reducing battery thickness increase during high temperature storage and improving cycle properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If liquid electrolyte is used, then battery capacity is achieved, but electrode degradation and safety issues occur due to gas generation and organic solvent decomposition

Engineering Contradiction:

Improvebattery capacityVSAvoidelectrode stability and safety

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the physical state of the electrolyte from liquid to gel polymer form. This parameter change maintains ion conductivity necessary for battery capacity while eliminating the volatility and decomposition issues of liquid organic solvents, thereby improving electrode stability and safety

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite gel polymer electrolyte system combining polymer matrix with gel components. This composite structure provides both the ion conductivity needed for battery capacity and the structural stability required to prevent electrode degradation and gas generation

Inventive Principle:

Principle #40Composite materials

2Speed

If liquid electrolyte is used, then ion conduction is achieved, but battery thickness increases during charge and discharge due to gas generation

Engineering Contradiction:

Improveion conduction speedVSAvoidbattery thickness

Core Design Contradiction:

SpeedVSLength of moving object

Solution Approach 1:

The patent changes the electrolyte from liquid to gel polymer form, which maintains sufficient ion conduction speed while eliminating gas generation. This prevents battery thickness increase during charge and discharge cycles

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If liquid electrolyte is used, then electrochemical reaction is enabled, but combustion risk increases at high temperature due to organic solvent volatility

Engineering Contradiction:

Improveelectrochemical reaction efficiencyVSAvoidcombustion risk and volatility

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent changes the electrolyte physical state from liquid to gel polymer, which maintains electrochemical reaction efficiency while eliminating the volatility and combustion risks associated with liquid organic solvents at high temperatures

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The gel polymer electrolyte creates a more stable, less reactive environment compared to liquid organic solvents, effectively reducing the combustion risk and harmful thermal effects at high operating temperatures

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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 gel polymer electrolyte composition improves battery lifespan, high-temperature storability, and capacity, while reducing metal precipitation and enhancing charge/discharge efficiency, thereby stabilizing the battery and maintaining performance.

Implementation Method 1

Methodology Applied

Scientific EffectIon mobility enhancement:

Implementation Method 2

A gel polymer electrolyte composition is developed, comprising a liquid electrolyte solvent, a lithium salt, a polymerization initiator

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentUS10276893B2Gel polymer electrolyte and lithium secondary battery comprising the same

Publication Date: 2019.04.30 LG ENERGY SOLUTION LTD

AI summary

The present invention relates to a composition for a gel polymer electrolyte comprising a liquid electrolyte solvent, a lithium salt, a polymerization initiator, and a mixed compound of a first compound and a second compound, and a lithium secondary battery comprising a positive electrode, a negative electrode, a separator, and a gel polymer electrolyte, wherein the gel polymer electrolyte is formed by polymerizing the composition for a gel polymer electrolyte. By comprising a mixed compound of a first compound and a second compound in which the first compound is an amine-based compound comprising polyethylene glycol as a functional group and the second compound is an epoxy-based compound, a composition for a gel polymer electrolyte of the present invention exhibits, when used in a lithium secondary battery, enhanced battery lifespan, excellent high temperature storability, and enhanced battery capacity property by readily inducing a hopping phenomenon.