Electrolyte sealing material

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Solution Overview

Problem

Existing electrolyte sealing materials for batteries and capacitors fail to provide high gas shielding properties, excellent electrical insulation, and resistance to electrolytes, leading to compound extraction and potential adverse effects on battery operation, particularly in high-temperature environments.

Innovation Solution

An electrolyte sealing material composed of ethylene/propylene-based copolymer rubber compounded with PTFE and/or titanium dioxide as fillers, ensuring a minimum 10 wt.% ratio, along with MT carbon black, to achieve desired insulation and electrolyte resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If silica is used as an insulating filler in rubber, then electrical insulation properties are improved, but chemical stability deteriorates because silica is dissolved by hydrogen fluoride from the electrolyte

Engineering Contradiction:
Improveelectrical insulation propertiesVSAvoidchemical stability
Core Design Contradiction:
Area of moving objectVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the filler material from silica to PTFE and/or titanium dioxide. These materials have different chemical properties that provide both high electrical insulation (volume resistivity ≥10^14 Ω·cm) and resistance to dissolution by hydrogen fluoride in the electrolyte, thus resolving the contradiction between insulation and chemical stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite filler systems combining PTFE and/or titanium dioxide with ethylene/propylene-based copolymer rubber. This composite material approach achieves synergistic effects where the filler provides insulation properties while the rubber matrix provides chemical stability and elasticity, solving both the insulation and chemical resistance requirements simultaneously.

Inventive Principle:
Principle #40Composite materials

2Loss of substance

If conventional rubber materials are used for electrolyte sealing, then gas shielding properties are improved, but compound extraction by electrolyte increases leading to adverse effects on battery operation

Engineering Contradiction:
Improvegas shielding propertiesVSAvoidcompound extraction
Core Design Contradiction:
Loss of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the rubber material by incorporating PTFE and/or titanium dioxide fillers at specific ratios (5-50 wt% of total filler content). This modification reduces the extraction of rubber compounds by the electrolyte to extremely low levels (≤5 ppm) while maintaining excellent gas shielding properties, thus resolving the contradiction between gas shielding and compound extraction.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If MT carbon black is used as the only filler to prevent compound extraction, then chemical stability is improved, but electrical insulation properties may be insufficient

Engineering Contradiction:
Improvechemical stabilityVSAvoidelectrical insulation properties
Core Design Contradiction:
ReliabilityVSArea of moving object

Solution Approach 1:

The patent creates a composite filler system combining MT carbon black with PTFE and/or titanium dioxide. The PTFE and titanium dioxide provide high electrical insulation properties, while MT carbon black maintains chemical stability and prevents compound extraction. This composite approach achieves both requirements simultaneously that cannot be met by MT carbon black alone.

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 material maintains excellent insulation properties and prevents compound extraction by electrolytes, ensuring stable battery operation and extended lifespan.

Implementation Method 1

PTFE and/or titanium dioxide having electrical insulation properties... insulation properties with a volume resistivity of 10^14 (2·cm or higher are required

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

they cannot be used for electrolyte sealing materials because they are dissolved by hydrogen fluoride generated from the electrolyte and have poor chemical stability

Methodology Applied
Scientific EffectChemical stability:

Data Source

PatentUS20250239701A1Electrolyte sealing material
Publication Date: 2025.07.24 NOK CORP

AI summary

An electrolyte sealing material that is an ethylene/propylene-based copolymer rubber composition obtained by compounding PTFE and/or titanium dioxide in ethylene/propylene-based copolymer rubber, wherein the amount of PTFE and/or titanium dioxide compounded in the total amount of fillers is 10 wt. % or more. The electrolyte sealing material has high gas shielding properties, excellent electrical insulation properties, and resistance to electrolytes, and that compounds in rubber are not extracted by the electrolyte, that can be suitably used as a sealing material for various batteries such as lithium ion batteries and nickel metal hydride batteries, electrolytic capacitors, electric double layer capacitors, and the like.