Electrode Binder Composition for Low-Viscosity High-Adhesion Slurries
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Solution Overview
Problem
The viscosity of electrode mixture slurries increases when using active materials with small particle sizes in non-aqueous electrolyte secondary batteries, affecting the adhesion and performance of the electrodes.
Innovation Solution
A binder composition containing a combination of vinylidene fluoride homopolymers with specific solution viscosities and ratios, along with an electroconductive auxiliary agent, is used to maintain high adhesion and prevent viscosity increases in the electrode mixture slurry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If active materials with small particle sizes are used, then energy density is improved, but slurry viscosity increases
Solution Approach 1:
The patent applies parameter changes by carefully controlling the molecular weight distribution and composition of the vinylidene fluoride polymer binder. By adjusting the polymer's inherent viscosity and molecular weight parameters, the slurry maintains appropriate flow characteristics even with small particle size active materials, preventing excessive viscosity increase while preserving high energy density
Solution Approach 2:
The patent uses composite materials by combining vinylidene fluoride polymer with specific additives and dispersants. This composite binder system works synergistically to reduce slurry viscosity while maintaining adhesion, allowing the use of small particle size active materials without suffering from excessive viscosity
2Strength
If vinylidene fluoride-based polymer is used as binder, then adhesion is improved, but slurry viscosity increases
Solution Approach 1:
The patent optimizes the inherent viscosity parameter of the vinylidene fluoride polymer within a specific range (0.3-1.5 dl/g). This parameter control ensures the polymer provides sufficient adhesion strength while maintaining slurry processability and preventing excessive viscosity increase
Solution Approach 2:
The patent applies local quality by using different polymer components with different functions: one component provides adhesion to the active material and current collector, while another component controls slurry viscosity. This functional differentiation within the binder system resolves the contradiction between adhesion and viscosity
Data Source
AI summary
Provided is a binder composition in which viscosity increases of an electrode mixture slurry is prevented or reduced while a high peel strength between a current collector and an electrode mixture layer is maintained.