Battery Electrode Binder Composition for Peel Strength and Slurry Viscosity
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Solution Overview
Problem
Conventional binder compositions for non-aqueous secondary battery electrodes face challenges in maintaining good viscousness while achieving high peel strength, which is essential for efficient electrode formation and performance.
Innovation Solution
A binder composition with a particulate polymer containing specific proportions of aromatic vinyl, aliphatic conjugated diene, and carboxyl group-containing monomer units, along with a controlled particle diameter ratio and pH, is developed to enhance both viscousness and peel strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional binder compositions are used, then good viscousness is maintained, but peel strength of the electrode is insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the proportions of aromatic vinyl monomer units (5-65 mass%), aliphatic conjugated diene monomer units (30-90 mass%), and carboxyl group-containing monomer units (2-9 mass%) in the particulate polymer. Additionally, the particle diameter ratio (Da/Db) is controlled within 1.05-2.0, and volume-average particle diameter (Db) within 100-170 nm. These parameter optimizations enable the binder composition to achieve both good viscousness for manufacturing and high peel strength for electrode performance.
2Reliability
If high peel strength is achieved, then electrode performance improves, but viscousness of the binder composition deteriorates
Solution Approach 1:
The patent employs composite materials by creating a multi-component particulate polymer system that combines aromatic vinyl, aliphatic conjugated diene, and carboxyl group-containing monomer units in specific proportions. This composite structure within the binder composition allows simultaneous achievement of appropriate viscousness for manufacturing processes and high peel strength for reliable electrode performance.
Data Source
AI summary
A binder composition for a non-aqueous secondary battery electrode contains a particulate polymer that includes an aromatic vinyl monomer unit in a proportion of not less than 5 mass % and not more than 65 mass %, an aliphatic conjugated diene monomer unit in a proportion of not less than 30 mass % and not more than 90 mass %, and a carboxyl group-containing monomer unit in a proportion of not less than 2 mass % and not more than 9 mass %. A ratio (Da/Db) of an average particle diameter Da of the particulate polymer measured by dynamic light scattering and a volume-average particle diameter Db of the particulate polymer measured by laser diffraction/scattering is not less than 1.05 and not more than 2.0. The volume-average particle diameter Db of the particulate polymer is not less than 100 nm and not more than 170 nm.