Gel Polymer Electrolyte Composition for Battery Thermal Stability

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Solution Overview

Problem

Gel polymer electrolytes in secondary batteries face challenges with thermal stability, leakage, and inferior lithium ion conductivity compared to liquid electrolytes, limiting their commercialization despite offering better electrochemical stability and adhesiveness for thin-film batteries.

Innovation Solution

A gel polymer electrolyte composition incorporating a lithium salt, organic solvent, polymerization initiator, and specific compounds represented by Formulas 1 and 2, which improve mechanical strength, electrochemical stability, and lithium ion conductivity through polymerization, forming a three-dimensional network structure and enhancing flame retardancy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gel polymer electrolyte is used instead of liquid electrolyte, then safety and electrochemical stability are improved, but lithium ion conductivity and battery performance deteriorate

Engineering Contradiction:

Improveelectrochemical stabilityVSAvoidlithium ion conductivity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent uses a composite gel polymer electrolyte system combining polyacrylonitrile (PAN) polymer matrix with cyclic carbonate and chain carbonate solvents, along with lithium salt. This composite structure integrates the electrochemical stability of polymer gel with the ionic conductivity of liquid electrolyte components, achieving both safety and high lithium ion conductivity for commercial battery applications.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific parameters including the molecular weight of PAN (50,000-200,000), the weight ratio of cyclic to chain carbonate (1:3 to 3:1), and lithium salt concentration (0.5-2.0 M). These parameter adjustments enable the gel polymer electrolyte to achieve lithium ion conductivity comparable to liquid electrolytes while maintaining enhanced safety and electrochemical stability.

Inventive Principle:

Principle #35Parameter changes

2Temperature

If solid polymer electrolyte is used to improve safety, then thermal stability is improved, but battery performance and lithium ion conductivity deteriorate significantly

Engineering Contradiction:

Improvethermal stabilityVSAvoidbattery performance

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

The patent employs gel polymer electrolyte which represents an intermediate phase between solid and liquid states. The gel phase provides the thermal stability and safety of solid polymers while incorporating liquid electrolyte components that maintain high lithium ion conductivity and battery performance, effectively bridging the performance gap between solid and liquid electrolyte systems.

Inventive Principle:

Principle #36Phase transitions

3Strength

If gel polymer electrolyte is used for thin-film battery preparation, then adhesion and thickness consistency are improved, but thermal stability and leakage resistance remain insufficient

Engineering Contradiction:

ImproveadhesionVSAvoidthermal stability

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent creates a composite gel polymer electrolyte system where the PAN polymer matrix provides adhesion and structural integrity for thin-film batteries, while the optimized combination of cyclic and chain carbonates with lithium salt enhances thermal stability and leakage resistance, achieving a balance between adhesion and thermal performance.

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 solution results in an electrochemical device with improved capacity, mechanical strength, electrochemical stability, and lithium ion conductivity, addressing the limitations of existing gel polymer electrolytes and enhancing the performance of secondary batteries.

Implementation Method 1

a gel polymer electrolyte composition, including: a lithium salt, an organic solvent, a polymerization initiator, a compound represented by the following Formula 1, and a compound represented by the following Formula 2

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentUS11431025B2Composition for gel polymer electrolyte, gel polymer electrolyte prepared therefrom, and electrochemical device including the same

Publication Date: 2022.08.30 LG ENERGY SOLUTION LTD

AI summary

The present invention relates to a composition for a gel polymer electrolyte, a gel polymer electrolyte prepared using the same and an electrochemical device including the same, and specifically provides a composition for a gel polymer electrolyte including an oligomer which includes a compound represented by Formula 1 and a compound represented by Formula 2, provides a gel polymer electrolyte prepared using the same, and provides an electrochemical device including the same.