VDF-TFE Fluoropolymer Binder for Metal-Adhering Dry Electrodes

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Solution Overview

Problem

Existing fluoropolymers like PTFE exhibit poor adhesion to metal current collectors in electrode manufacturing, making them unsuitable for efficient dry electrode processes, and existing VDF/TFE copolymers do not provide sufficient adhesion and processability for low-temperature extrusion.

Innovation Solution

Development of VDF-based copolymers with specific melting points, allowing for improved adhesion to metals and suitable for dry electrode preparation processes, including a composition comprising recurring units of VDF and TFE with at least two melting points, one below 220°C and one above 250°C, enabling extrusion at low temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If VDF/TFE copolymers are used for binder application, then processability is improved, but adhesion to metal deteriorates

Engineering Contradiction:

ImproveprocessabilityVSAvoidadhesion to metal

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The invention optimizes the compositional parameters of VDF/TFE copolymers by controlling the VDF content within 50-80 mol% and ensuring specific melting point characteristics. This precise parameter control enables the copolymer to maintain good processability for extrusion while simultaneously achieving outstanding adhesion to metal current collectors, resolving the contradiction between ease of manufacture and adhesion strength.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If wet process is used for electrode manufacturing, then good dispersion of materials is achieved, but drying time and cost increase

Engineering Contradiction:

Improvedispersion of materialsVSAvoiddrying time

Core Design Contradiction:

Stability of the object's compositionVSLoss of time

Solution Approach 1:

The invention replaces the wet process (which relies on liquid medium for dispersion followed by drying) with a dry process using VDF-based copolymer binders. The copolymer's specific melting point characteristics enable direct dry mixing and hot pressing of electrode materials without requiring solvent dispersion and subsequent drying, thereby eliminating drying time and cost while maintaining good material dispersion through the binder's cohesive properties.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 VDF-based copolymers demonstrate enhanced adhesion to metal current collectors, facilitating efficient electrode production by dry processes and maintaining good electrical properties.

Implementation Method 1

polymer (A) has at least two melting points, one melting point lower than 220 °C and one melting point higher than 250 °C

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentEP4441805B1TFE-based fluoropolymers with outstanding metal-adhesion properties

Publication Date: 2026.02.25 SOLVAY SPECIALTY POLYMERS ITALY SPA

AI summary

The present invention relates to VDF-based fluoropolymers with outstanding metal-adhesion properties for use as a binding agent for electrodes for batteries.