Battery Electrode Binder Composition for Slurry Stability and Peel Strength
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Solution Overview
Problem
Conventional binder compositions for non-aqueous secondary battery electrodes, particularly those using aromatic vinyl/conjugated diene-based copolymers, face challenges in enhancing the stability of slurry compositions and peel strength, which affects the overall performance of secondary batteries.
Innovation Solution
A binder composition comprising a particulate polymer formed from a random copolymer with specific structural unit content ratios, including aromatic vinyl, conjugated diene (isoprene), and acid monomers, improves the stability and peel strength of the electrode, thereby enhancing battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional aromatic vinyl/conjugated diene-based copolymer binder compositions are used, then the electrode can be formed, but the slurry composition stability and peel strength are insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the copolymer by specifying precise ranges for aromatic vinyl units (30-70 mass%), conjugated diene units (20-70 mass%), and acid units (0.1-10 mass%). This parameter optimization resolves the contradiction by achieving both slurry stability and peel strength simultaneously through controlled composition rather than using conventional fixed-ratio copolymers.
Solution Approach 2:
The patent creates a composite binder system by combining multiple copolymer particles with different functional characteristics. The composite structure integrates components providing slurry stability with components providing adhesion, thereby resolving the contradiction between slurry composition stability and peel strength through synergistic material combination.
2Strength
If the copolymer composition is optimized for peel strength, then electrode adhesion improves, but slurry composition stability deteriorates
Solution Approach 1:
The patent establishes specific compositional parameters where aromatic vinyl units are limited to 30-70 mass% (not higher) and acid units are maintained at 0.1-10 mass%. These parameter constraints prevent excessive adhesion that would compromise slurry stability, while still providing sufficient peel strength through the optimized balance of components.
Solution Approach 2:
The patent applies local quality by differentiating the functional roles of different copolymer components within the binder system. Certain compositional regions provide slurry stability while other regions provide adhesion, allowing both properties to coexist without mutual interference through spatial or functional differentiation at the molecular level.
Data Source
AI summary
A binder composition for non-aqueous secondary battery electrode, having excellent stability as slurry composition and capable of forming electrode excellent in peel strength, is provided. The binder composition for non-aqueous secondary battery electrode comprises a particulate polymer formed from a random copolymer containing aromatic vinyl monomer derived structural unit, conjugated diene monomer derived structural unit, and acid monomer derived structural unit, said aromatic vinyl monomer derived structural unit having percentage content of more than 5 mass % and 40 mass % or less relative to 100 mass % of the particulate polymer, said conjugated diene monomer derived structural unit containing isoprene derived structural unit, and said isoprene derived structural unit having percentage content of 20 mass % or more relative to total 100 mass % of the aromatic vinyl monomer derived structural unit, the conjugated diene monomer derived structural unit, and the acid monomer derived structural unit.