Binder Composition Monomer Oligomer Control for Electrode Slurry Stability
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Solution Overview
Problem
Nonaqueous electrolyte secondary batteries, such as lithium ion batteries, face issues with electrode slurry stability and uniformity, leading to variability in charging and discharging capacities, which affects battery lifetime due to aggregation and depression of active materials during preservation and coating.
Innovation Solution
A binder composition with a monomer and oligomer content ratio of 300 ppm or less, where the oligomer has a weight-average molecular weight of 3,000 or less, is used to stabilize the slurry by preventing monomer and oligomer adsorption on active materials, ensuring homogeneous dispersion and improved electrode thickness and density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If monomer and oligomer are present in the binder composition, then the binder can provide binding function, but the slurry stability deteriorates due to adsorption on active material surfaces
Solution Approach 1:
The patent applies parameter changes by strictly controlling the content of monomer and oligomer in the binder composition to 300 ppm or less. This quantitative parameter control prevents the adsorption of monomer and oligomer on active material surfaces, thereby maintaining slurry stability while preserving the necessary binding function through the polymer component.
2Stability of the object's composition
If polymer adsorbs onto active material surface, then dispersion stability improves, but monomer and oligomer adsorption inhibits this process
Solution Approach 1:
The patent applies preliminary anti-action by pre-controlling the monomer and oligomer content in the binder composition to 300 ppm or less before the slurry preparation process. This preliminary control prevents the harmful adsorption of monomer and oligomer on active material surfaces, ensuring that the polymer can adsorb effectively and provide stable dispersion without competition from lower molecular weight components.
3Manufacturing precision
If slurry aggregation occurs during preservation, then electrode thickness and density become ununiform, but this can be prevented by optimizing binder composition
Solution Approach 1:
The patent applies parameter changes by optimizing the binder composition parameters, specifically controlling monomer and oligomer content to 300 ppm or less. This parameter optimization prevents slurry aggregation during preservation, ensuring uniform electrode thickness and density while maintaining slurry homogeneity throughout the manufacturing process.
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 solution provides a slurry with enhanced homogeneity and stability, resulting in electrodes with consistent thickness and density, and nonaqueous electrolyte secondary batteries with reduced variability in battery properties, suitable for small electronics and automotive applications.
Implementation Method 1
an active material can be stably dispersed by polymer which adsorbs onto a surface of the active material
Implementation Method 2
adsorption of the polymer is inhibited due to their adsorption onto the surfaces of active material
Data Source
AI summary
The present invention aims at providing slurry for electrodes having advantageous homogeneity and stability, an electrode having advantageous homogeneous thickness and density, and further, a nonaqueous electrolyte secondary battery having small variability in battery properties.In the present invention, slurry for electrodes is produced by using the binder composition used for manufacturing a nonaqueous electrolyte secondary battery wherein polymers for binding active materials are dissolved or dispersed in organic solvent or water, and a total sum of content ratios of monomer and oligomer is 300 ppm or less.