Hydrophilic Binder Copolymer for Water-Based Lithium Battery Electrodes

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Solution Overview

Problem

Existing lithium ion battery binders, such as polyvinylidene fluoride, suffer from low bonding strength, poor high-temperature electrochemical stability, and require flammable, explosive, and toxic organic solvents, necessitating a water-based binder with improved adhesive properties and processability.

Innovation Solution

A hydrophilic polymer is developed by copolymerizing a conjugated diene, a monoolefin, and a hydrophilic monomer, enhancing adhesiveness and affinity with electrode materials, thereby reducing floating and roll sticking issues during the battery manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polyvinylidene fluoride is used as a binder material, then high dielectric constant and strong corrosion resistance are achieved, but low bonding strength and poor high-temperature electrochemical stability occur

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidbonding strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent uses a composite binder system comprising carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR) in a mass ratio of 9:1 to 1:9. This composite approach combines the water solubility and corrosion resistance of CMC with the elasticity and adhesion of SBR, achieving both high bonding strength and excellent corrosion resistance that neither material can achieve alone.

Inventive Principle:

Principle #40Composite materials

2Reliability

If polyvinylidene fluoride is used as a binder material, then strong corrosion resistance is achieved, but poor high-temperature electrochemical stability occurs

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidhigh-temperature electrochemical stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent modifies the binder composition by incorporating SBR, which introduces elastic properties and improved adhesion to the active material particles. This compositional parameter change enhances high-temperature electrochemical stability while maintaining the corrosion resistance provided by the CMC base material.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If organic dispersion medium such as N-NMP is used as a dispersant, then good processability is achieved, but flammability, explosiveness, volatility, and toxicity occur

Engineering Contradiction:

ImproveprocessabilityVSAvoidflammability and toxicity

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the expensive and hazardous organic dispersant N-NMP with water, which is non-flammable, non-toxic, and environmentally friendly. The binder system is specifically designed to be water-soluble, allowing water to serve as an effective dispersant medium that eliminates all the harmful properties associated with organic solvents while maintaining good processability.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Ease of manufacture

If organic dispersion medium such as N-NMP is used as a dispersant, then good processability is achieved, but high recovery cost occurs

Engineering Contradiction:

ImproveprocessabilityVSAvoidrecovery cost

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent eliminates the need for expensive organic dispersant recovery processes by using water as the dispersant medium. Water can be easily removed through drying without requiring complex recovery systems, significantly reducing manufacturing costs and energy consumption associated with solvent recovery.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 hydrophilic polymer improves the adhesive force and stability of the binder, leading to enhanced performance and longevity of lithium ion secondary batteries by preventing floating and roll sticking, resulting in a longer battery life.

Implementation Method 1

by copolymerizing a conjugated diene, a monoolefin, and a hydrophilic monomer having a structure represented by the following formula I

Methodology Applied

Scientific EffectCopolymerization: Chemical Bonding

Implementation Method 2

at least one of R1, R2, and R3 represents the same or different hydrophilic groups, and the others of which represent hydrogen atoms or, a linear or branched alkyl or alkoxy with 1-4 carbon atoms

Methodology Applied

Scientific EffectHydrophilic interaction: Hydrophile

Data Source

PatentUS12590175B2Hydrophilic polymer, method of preparing the same, and lithium secondary battery containing the hydrophilic polymer

Publication Date: 2026.03.31 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

AI summary

The present disclosure relates to a hydrophilic polymer and a method for preparing the same. The hydrophilic polymer is characterized in that it is a copolymer of a conjugated diene, a monoolefin and a hydrophilic monomer represented by Formula I. In the Formula I, X1, X2 and X3 are each independently selected from hydrogen atoms, or a linear or branched alkyl with 1-4 carbon atoms. At least one of R1, R2 and R3 is hydrophilic group; and the others are each independently selected from hydrogen atoms or, an alkyl or alkoxy with 1-4 carbon atoms.