Aqueous Battery Sealant Composition for Strength and Flexibility

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Solution Overview

Problem

Existing aqueous sealant compositions for nonaqueous electrolyte batteries lack sufficient sealant layer properties, particularly in terms of strength and flexibility, and often use volatile organic compounds (VOCs), which are environmentally harmful.

Innovation Solution

An aqueous sealant composition comprising an olefinic polymer dispersion, specifically a partial copolymer of polyethylene, polypropylene, or ethylene-propylene polymers with polymerizable unsaturated organic acids, combined with polyvinyl alcohol, providing a self-emulsified modified olefinic polymer for enhanced viscosity and solid content concentration, forming a robust and flexible sealant layer without VOCs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If an aqueous sealant composition is used to eliminate VOCs, then environmental friendliness is improved, but the strength and flexibility of the sealant layer deteriorate

Engineering Contradiction:
ImproveVOC emissionsVSAvoidsealant layer strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent uses a composite system combining water-soluble polymer (polyvinyl alcohol) and water-dispersible polymer (olefinic polymer modified with carboxylic acid groups). This composite approach allows the aqueous sealant to achieve both environmental friendliness and sufficient mechanical strength by leveraging the complementary properties of the two polymer systems.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific parameters including the molecular weight of polyvinyl alcohol (10,000-200,000), the content of carboxylic acid groups in the olefinic polymer (0.1-10 mmol/g), and the ratio between the two polymers. These parameter adjustments enable the aqueous sealant to form a sealant layer with adequate strength and flexibility without using organic solvents.

Inventive Principle:
Principle #35Parameter changes

2Strength

If pitch-based materials or conventional sealants are used, then sealant layer strength is improved, but VOC usage increases causing environmental harm

Engineering Contradiction:
Improvesealant layer strengthVSAvoidVOC emissions
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent fundamentally changes the solvent parameter from organic to aqueous, eliminating VOC emissions. To compensate for the typically lower strength of aqueous systems, it carefully selects and optimizes the polymer components and their ratios, achieving a balance between environmental friendliness and performance.

Inventive Principle:
Principle #35Parameter changes

3Strength

If the solid content concentration of the aqueous dispersion is increased to improve sealant layer properties, then viscosity increases making application difficult

Engineering Contradiction:
Improvesealant layer propertiesVSAvoidapplication ease
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent optimizes the solid content concentration of the aqueous dispersion within a specific range (5-60%) to balance two opposing requirements: higher solid content provides better sealant layer properties, while lower solid content ensures easier application. This parameter optimization allows the sealant to be both effective and easy to apply.

Inventive Principle:
Principle #35Parameter changes

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 composition achieves a sealant layer with excellent wettability, film strength, flexibility, and sealability, effectively preventing electrolyte leakage and moisture intrusion while being environmentally friendly by eliminating VOCs.

Implementation Method 1

a sealant layer having excellent properties can be obtained

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3444863B1Aqueous sealant composition for nonaqueous electrolyte battery
Publication Date: 2024.05.01 ZEON CORP

AI summary

Disclosed is an aqueous sealant composition for a nonaqueous electrolyte battery by which a sealant layer having excellent properties can be obtained. An aqueous sealant composition for a nonaqueous electrolyte battery of the present disclosure comprises an aqueous dispersion in an amount of 70 mass% or more and 97 mass% or less by mass of solid content, wherein the aqueous dispersion comprises an olefinic polymer as a main component.