Fluorinated Battery Binder Composition for Stable Electrode Slurries

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Solution Overview

Problem

Existing secondary battery compositions face challenges with binders having low solubility in solvents, leading to inadequate slurry formation and electrode performance, particularly with sulfide-based solid electrolyte particles, where gelation issues occur, affecting the homogeneity and functionality of the electrode.

Innovation Solution

A fluorine-containing polymer with a structural unit derived from 1,2-difluoroethylene is used as a binder, offering excellent solubility and stability, which improves the dispersibility and viscosity of the electrode composition, allowing for the use of low-boiling point solvents and reduced drying temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional binders are used, then electrode structure is maintained, but solubility in solvent is low leading to inadequate slurry formation

Engineering Contradiction:

Improveelectrode structureVSAvoidslurry formation

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical structure parameters of the binder by introducing fluorine-containing polymer units with specific molecular weights and compositions. This modifies the solubility parameters of the binder to achieve optimal dissolution in the solvent, resolving the contradiction between maintaining electrode structure and enabling adequate slurry formation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite binder system comprising fluorine-containing polymer units combined with specific additives and solvents. This composite material approach enhances both the structural integrity of the electrode and the slurry formation characteristics by leveraging the synergistic effects of different components.

Inventive Principle:

Principle #40Composite materials

2Reliability

If conventional binders are used, then electrode structure is maintained, but gelation occurs affecting homogeneity

Engineering Contradiction:

Improveelectrode structureVSAvoidslurry homogeneity

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent modifies the chemical and physical parameters of the binder by using fluorine-containing polymers with specific molecular weights and functional groups. These parameter changes prevent gelation by optimizing the interaction between binder, solvent, and solid electrolyte particles, thereby maintaining slurry homogeneity while preserving electrode structure.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The fluorine-containing binder acts as an intermediary substance that mediates between the solvent and sulfide-based solid electrolyte particles. It prevents direct harmful interactions that cause gelation while maintaining proper adhesion and structural integrity of the electrode.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If high-boiling point solvents are used, then solubility is improved, but drying time increases

Engineering Contradiction:

ImprovesolubilityVSAvoiddrying time

Core Design Contradiction:

Ease of manufactureVSLoss of time

Solution Approach 1:

The patent changes the solvent parameters by selecting specific low-boiling point solvents that are compatible with the fluorine-containing binder. This parameter change allows the use of volatile solvents without sacrificing solubility, as the fluorine-containing polymer maintains excellent dissolution in these lighter solvents, thereby reducing drying time.

Inventive Principle:

Principle #35Parameter changes

4Use of energy by stationary object

If drying temperature is reduced, then energy consumption is lowered, but solubility and dispersibility are affected

Engineering Contradiction:

Improvedrying energyVSAvoiddispersibility

Core Design Contradiction:

Use of energy by stationary objectVSStability of the object's composition

Solution Approach 1:

The patent optimizes the chemical parameters of the binder-solvent system by using fluorine-containing polymers with specific functional groups and molecular weights. This creates a system with enhanced solubility and dispersibility that remains stable even at reduced drying temperatures, allowing energy-efficient processing without compromising composition stability.

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 fluorine-containing polymer enhances the solubility and stability of the secondary battery composition, resulting in improved electrode performance with better dispersibility and viscosity, and lower resistivity, while enabling the use of low-boiling point solvents to shorten the drying process.

Implementation Method 1

A fluorine-containing polymer with a structural unit derived from 1,2-difluoroethylene is used as a binder, offering excellent solubility and stability

Methodology Applied

Scientific EffectSolubility: Solvation

Implementation Method 2

allowing for the use of low-boiling point solvents and reduced drying temperatures

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS20250023055A1Secondary battery composition

Publication Date: 2025.01.16 DAIKIN INDUSTRIES LTD

AI summary

Provided is a secondary battery composition that uses a polymer having a structure originated from 1,2-difluoroethylene. A secondary battery composition comprising a fluorine-containing polymer and a solvent, wherein the fluorine-containing polymer is the polymer comprising a structural unit represented by formula (1):