Battery Electrode Binder Composition for Stable Slurry Viscosity
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Solution Overview
Problem
Conventional binder compositions for non-aqueous secondary battery electrodes face challenges in maintaining viscosity stability and achieving high peel strength, particularly during long-term storage and electrode formation.
Innovation Solution
A binder composition incorporating a particulate polymer with specific chemical composition and particle properties, including aromatic vinyl, conjugated diene, and acidic group-containing monomer units, with acidic groups partially in the form of salts, and controlled particle diameters, is used to enhance viscosity stability and peel strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a conventional binder composition is used, then the slurry composition can be produced, but the viscosity stability deteriorates during long-term storage
Solution Approach 1:
The invention changes the particle size parameters of the particulate polymer (average particle diameter X: 140-300 nm, particle diameter ratio X/Y: 1.05-2.00) to achieve optimal viscosity stability. By controlling these physical parameters within specific ranges, the binder composition maintains stable viscosity during long-term storage while ensuring proper adhesion and processing characteristics.
2Strength
If a binder composition with strong adhesion is used, then peel strength increases, but viscosity stability may deteriorate
Solution Approach 1:
The invention optimizes the chemical composition parameters of the particulate polymer, specifically controlling the content of aromatic vinyl monomer units (5-40 mass%), conjugated diene monomer units (20-70 mass%), and acidic group-containing monomer units (0.1-10 mass%). This parameter optimization achieves a balance between adhesion strength and viscosity stability.
Solution Approach 2:
The invention uses a composite particulate polymer structure combining multiple monomer units with different functions: aromatic vinyl units for structural backbone, conjugated diene units for flexibility and adhesion, and acidic group-containing units for polarity and bonding. This composite structure enables simultaneous achievement of high peel strength and viscosity stability.
3Strength
If the particle size of the particulate polymer is reduced, then the adhesion improves, but the viscosity control becomes difficult
Solution Approach 1:
The invention precisely controls the particle size parameters (average diameter X: 140-300 nm, ratio X/Y: 1.05-2.00) to achieve optimal balance between adhesion and viscosity control. This specific particle size range provides sufficient surface area for adhesion while maintaining appropriate flow characteristics.
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 proposed binder composition achieves excellent viscosity stability and peel strength for non-aqueous secondary battery electrodes, ensuring effective adhesion and performance over time.
Implementation Method 1
a binder composition containing a binder does not cause the viscosity of a slurry composition produced used the binder composition to significantly increase or decrease from designed viscosity straight after production even in a situation in which the slurry composition is stored for a long time
Implementation Method 2
it is desirable that a binder composition containing a binder does not cause the viscosity of a slurry composition produced used the binder composition to significantly increase or decrease from designed viscosity straight after production even in a situation in which the slurry composition is stored for a long time
Data Source
AI summary
Provided is a binder composition for a non-aqueous secondary battery electrode with which it is possible to produce a slurry composition that has excellent viscosity stability and is capable of producing an electrode having excellent peel strength. The binder composition contains a particulate polymer and water. The particulate polymer includes an aromatic vinyl monomer unit, a conjugated diene monomer unit, and an acidic group-containing monomer unit, wherein an acidic group of the acidic group-containing monomer unit is at least partially in a form of a salt. The particulate polymer has an average particle diameter X according to cumulant method analysis as measured by dynamic light scattering of 140 nm to 300 nm. A particle diameter ratio X/Y calculated as a ratio of the average particle diameter X relative to a volume-average particle diameter Y of the particulate polymer measured by laser diffraction/scattering is 1.05 to 2.00.