Core-Shell Battery Binder for Adhesion and Low Resistance

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Solution Overview

Problem

Existing binders for rechargeable lithium batteries face a trade-off between adhesive strength and electrical resistance, with high adhesive strength often leading to high resistance, which affects battery performance.

Innovation Solution

A binder with a core-shell structure, comprising a (meth)acrylic acid-based monomer, a (C1-C10) alkylene glycol-based monomer, and a zwitterionic vinyl- or (meth)acryl-based monomer, which enhances adhesive strength while reducing electrical resistance by improving lithium ion conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If binders with high adhesive strength are used, then adhesive strength is improved, but electrical resistance increases

Engineering Contradiction:
Improveadhesive strengthVSAvoidelectrical resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The binder is designed as a composite material comprising three distinct structural units: (meth)acrylic acid-based units for adhesion, alkylene glycol-based units for flexibility and ion transport, and zwitterionic vinyl/methacryl-based units for enhanced ionic conductivity. This composite structure allows simultaneous achievement of high adhesive strength and low electrical resistance by combining materials with complementary properties.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different regions of the binder molecule are assigned specific functions: the (meth)acrylic acid-based structural units provide localized adhesive properties for bonding electrode materials, while the zwitterionic vinyl/methacryl-based units create localized high-ion-conductivity pathways. This spatial differentiation of functional properties within the binder structure enables optimization of both adhesion and electrical resistance independently.

Inventive Principle:
Principle #3Local quality

2Strength

If high adhesive strength binders are used, then bonding performance is improved, but battery performance deteriorates due to high resistance

Engineering Contradiction:
Improvebonding performanceVSAvoidbattery performance
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The binder combines three types of structural units in specific proportions to achieve both strong bonding and high productivity. The alkylene glycol-based units with flexible chains facilitate rapid lithium ion diffusion, directly improving charging/discharging rates and overall battery productivity, while maintaining strong adhesion through the acrylic acid units.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The introduction of zwitterionic vinyl/methacryl-based structural units fundamentally changes the ionic conductivity parameter of the binder. These units create highly conductive pathways for lithium ions, reducing resistance and enabling faster ion transport, which directly enhances battery productivity during rapid charging and discharging operations.

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 binder improves the performance of rechargeable lithium batteries by balancing adhesive strength and resistance, facilitating better manufacturing and reducing side effects during rapid charging.

Implementation Method 1

a third structural unit derived from a zwitterionic vinyl-based monomer or a zwitterionic (meth)acryl-based monomer

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentEP4700960A1Binder for rechargeable lithium battery, electrode including the same and rechargeable lithium battery including the same
Publication Date: 2026.02.25 SAMSUNG SDI CO LTD
  • EP4700960A1 patent drawingFigure 1
  • EP4700960A1 patent drawingFigure 2
  • EP4700960A1 patent drawingFigure 3

AI summary

The present invention relates to a binder for a rechargeable lithium battery having a core-shell structure. The shell includes a first structural unit derived from a (meth)acrylic acid-based monomer; a second structural unit derived from a (C1-C10) alkylene glycol-based monomer; and a third structural unit derived from a zwitterionic vinyl-based monomer or a zwitterionic (meth)acryl-based monomer. The binder for a rechargeable lithium battery has high adhesive strength and low resistance, and thus can contribute to improving the performance of a rechargeable lithium battery.