Battery Electrode Binder Composition for Tackiness and Peel Strength
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Solution Overview
Problem
Conventional binder compositions for non-aqueous secondary batteries face challenges in maintaining good tackiness while increasing peel strength, particularly during high-speed slurry composition coating, which affects electrode production efficiency and quality.
Innovation Solution
A binder composition for non-aqueous secondary battery electrodes is formulated with specific ratios of average particle diameter and viscosity increase rates, utilizing particulate binders with core-shell structures and tailored monomer unit compositions to enhance tackiness and peel strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional binder compositions are used to improve tackiness, then binder production efficiency is improved, but peel strength of the electrode is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the binder by incorporating specific monomer units (aromatic vinyl, aliphatic conjugated diene, and carboxyl group-containing monomer units) in controlled ratios. This compositional parameter change enables the binder to achieve both good tackiness for production efficiency and high peel strength for electrode adhesion
Solution Approach 2:
The patent creates a composite binder material by combining multiple types of monomer units with different functional properties. The aromatic vinyl monomer provides structural backbone, the aliphatic conjugated diene monomer enhances flexibility and tackiness, and the carboxyl group-containing monomer improves adhesion to the current collector, achieving synergistic effects that resolve the contradiction between tackiness and peel strength
2Productivity
If high-speed slurry composition coating is performed to increase productivity, then electrode production speed is improved, but peel strength of the electrode decreases
Solution Approach 1:
The patent performs preliminary action by pre-forming particulate binder particles with specific surface properties and compositional structure before the coating process. These pre-engineered particles maintain stable tackiness during high-speed coating, ensuring that even when slurry is applied rapidly, the binder can still provide sufficient adhesion force to achieve high peel strength in the final electrode product
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 composition achieves excellent tackiness and peel strength, enabling high-speed electrode production with improved battery performance, including reduced internal resistance and enhanced cycle characteristics.
Implementation Method 1
ensure sufficiently high close adherence between an electrode mixed material layer and a current collector (i.e., peel strength of an electrode)
Data Source
AI summary
Provided is a binder composition for a non-aqueous secondary battery electrode that has good tackiness and that enables the formation of an electrode for a non-aqueous secondary battery having excellent peel strength. The binder composition for a non-aqueous secondary battery electrode contains a particulate binder and water. A ratio of an average particle diameter Da of the particulate binder measured by dynamic light scattering at pH 8.0 relative to a volume-average particle diameter Db of the particulate binder measured by laser diffraction/scattering is within a specific range. When viscosity of the binder composition at pH 6.0 and viscosity of the binder composition at pH 8.0 as measured under specific conditions are respectively taken to be η1 and η2, a viscosity increase rate, which is calculated by formula (I): viscosity increase rate={(η2−η1)/η1}, is within a specific range.