Battery Washer Adhesive With Fat-Soluble Leak Indicator

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Solution Overview

Problem

Existing washers for secondary batteries face issues with contamination and malfunction due to reduced cohesion force among adhesive components, especially when using water-soluble indicators, leading to manufacturing facility contamination and battery exterior defects.

Innovation Solution

A washer with a fat-soluble indicator component and adhesive layer, manufactured using organic solvents, to enhance cohesion force and prevent contamination, allowing easy identification of electrolyte leakage through color change.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a water-soluble indicator is used in the adhesive layer, then the indicator can be easily dissolved and applied, but the cohesion force among adhesive components is reduced causing contamination and malfunction

Engineering Contradiction:
Improveease of indicator applicationVSAvoidcohesion force of adhesive
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the solubility parameter of the indicator from water-soluble to fat-soluble, allowing it to be dissolved in organic solvents instead of water. This parameter change enables the indicator to be applied while maintaining adhesive cohesion force, as organic solvents do not interfere with the adhesive bonding mechanism.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces organic solvents as an intermediary medium to dissolve the fat-soluble indicator. This intermediary allows the indicator to be incorporated into the adhesive layer without using water, thereby preventing the reduction of adhesive cohesion force while still achieving easy indicator application.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the washer covers the electrolyte injection inlet, then the battery structure is sealed and protected, but electrolyte leakage cannot be easily detected

Engineering Contradiction:
Improvesealing protectionVSAvoidelectrolyte leakage detection
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent incorporates an indicator component in the adhesive layer that undergoes color change when it comes into contact with leaked electrolyte. This allows visual detection of electrolyte leakage through the washer material, maintaining sealing protection while enabling leakage detection.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The patent replaces the need for mechanical disassembly (removing the washer to check for leakage) with a chemical/optical detection method. The color-changing indicator provides visual information about electrolyte leakage without requiring physical access to the injection inlet.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 washer prevents manufacturing facility contamination and battery exterior defects while enabling easy visual detection of electrolyte leakage, ensuring improved adhesion and longevity.

Implementation Method 1

the color of which changes in a specific acidic region formed by gas generated by an electrolyte and/or an electrolyte side reaction

Methodology Applied
Scientific EffectColor change of indicator in acidic region: Thermochromism

Implementation Method 2

an adhesive component for coupling with a crimping portion of a can of the washer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3703150B1Washer for secondary battery, secondary battery including same, and method for manufacturing washer for secondary battery
Publication Date: 2025.08.20 LG ENERGY SOLUTION LTD
  • EP3703150B1 patent drawingFigure 1~3
  • EP3703150B1 patent drawingFigure 4
  • EP3703150B1 patent drawingFigure 5(a)~6

AI summary

The present invention relates to a washer for a secondary battery including a film layer and an adhesive layer disposed on at least one surface of the film layer, wherein the adhesive layer includes an adhesive component and an indicator component, and the indicator component is fat-soluble, a secondary battery including the same, and a method for manufacturing the washer.