Gel Electrolyte Peeling Index Control for Optical Strain Prevention

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Solution Overview

Problem

Gel electrolytes tend to peel from non-adhesive protective films during conveyance and storage, leading to optical strain and deformation, which is not addressed by existing methods that compromise ionic conductivity or require specific environmental conditions.

Innovation Solution

A gel electrolyte with a peeling index of 5.5 mm^-1 to 7.5 mm^-1, achieved by a cured product of an electrolyte composition containing a binder resin and supporting electrolyte, ensuring self-adhesiveness and easy peelability, measured through a probe tack test.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a gel electrolyte is used, then high ionic conductivity is achieved, but the electrolyte peels from protective films during conveyance and storage

Engineering Contradiction:
Improveionic conductivityVSAvoidadhesiveness
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent changes the physical and chemical parameters of the gel electrolyte by controlling the crosslinking degree of the polymer network and the composition ratio of liquid electrolyte to polymer. By adjusting these parameters, the gel electrolyte achieves optimal balance between adhesiveness (to prevent peeling) and ionic conductivity (for electrochemical performance), resolving the contradiction between these two properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The gel electrolyte is formulated as a composite material consisting of a polymer matrix (such as polyacrylonitrile, carboxymethyl cellulose, or starch) combined with liquid electrolyte. This composite structure provides both the mechanical strength needed for adhesiveness and the ionic conductivity required for electrochemical function, simultaneously addressing both requirements.

Inventive Principle:
Principle #40Composite materials

2Strength

If the gel electrolyte has high self-adhesiveness, then peeling is prevented during conveyance and storage, but the electrolyte becomes difficult to peel for use

Engineering Contradiction:
ImproveadhesivenessVSAvoidpeelability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent carefully controls the adhesiveness parameters of the gel electrolyte by adjusting polymer concentration, crosslinking degree, and liquid electrolyte content. This creates an optimal adhesiveness level that is sufficient to prevent peeling during conveyance and storage but remains low enough to allow easy peeling when needed for device assembly or replacement.

Inventive Principle:
Principle #35Parameter changes

3Strength

If protective films with adhesive layers are used, then peeling is prevented, but the films migrate into the electrolyte and cause instability

Engineering Contradiction:
ImproveadhesivenessVSAvoidelectrolyte stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The gel electrolyte itself acts as an intermediary layer between the protective films and the electrochemical elements. The gel's controlled adhesiveness provides sufficient bonding to prevent peeling during handling, while its composition is optimized to prevent migration of protective film materials into the electrolyte, thus maintaining electrolyte stability and preventing performance degradation.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Prevents peeling during conveyance and storage while maintaining ionic conductivity, allowing easy peeling from protective films without deformation or damage, thus preventing optical strain.

Implementation Method 1

The gel electrolyte is produced as a polymer swelled with a liquid electrolyte through a polymerization reaction in the liquid electrolyte mixed with a monomer

Methodology Applied
Scientific EffectPolymerization:

Implementation Method 2

produced through swelling of a polymer by immersion of a polymer matrix, which has been prepared previously by polymerization, in a liquid electrolyte

Methodology Applied
Scientific EffectSwelling:

Implementation Method 3

the liquid electrolyte in the polymer matrix mainly takes charge in ionic conduction

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 4

liquid electrolytes obtained by dissolving supporting electrolytes in water or organic solvents

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 5

a gel electrolyte having self-adhesiveness that prevents the gel electrolyte from peeling from non-adhesive protective films

Methodology Applied
Scientific EffectCrosslinking:

Data Source

PatentEP4305491B1Gel electrolyte and electrochromic element
Publication Date: 2025.04.02 RICOH CO LTD
  • EP4305491B1 patent drawingFigure 1~2
  • EP4305491B1 patent drawingFigure 3~4
  • EP4305491B1 patent drawing

AI summary

A gel electrolyte includes a cured product of an electrolyte composition containing a binder resin and a supporting electrolyte. The gel electrolyte has a peeling index of 5.5 mm-1 or greater but 7.5 mm-1 or less. The peeling index is obtained by dividing a maximum stress by an integral value obtained by integrating stress based on peeling distance, where the stress, peeling distance, and maximum stress are measured by probe tack test performed at environmental condition of 25°C by bringing stainless steel probe having diameter of 5 mm into contact with the gel electrolyte having average thickness of 700 micrometers from above the gel electrolyte at a speed of 120 mm/second, keeping the stainless steel probe under pressing load of 40 gf for a pressing load retention time of 5 seconds, and peeling the stainless steel probe in perpendicular direction at speed of 400 mm/second.