Modified Graphite Anodes With Bound Binder to Prevent SBR Floating
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Solution Overview
Problem
The uneven distribution of binders in the negative electrode of secondary batteries, particularly styrene-butadiene rubber (SBR), leads to performance deterioration due to floating issues during the drying process.
Innovation Solution
A modified graphite is developed by covalently linking a binder moiety with a specific functional group to the graphite moiety, eliminating the need for free-state binders and enhancing dispersity and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a binder (SBR) is used in the negative electrode, then adhesion is improved, but uneven distribution and floating occur leading to performance deterioration
Solution Approach 1:
The patent combines the binder and graphite particles into a single integrated structure by covalently linking SBR binder molecules to the graphite surface. This merging eliminates the separation between binder and active material, preventing binder floating while maintaining adhesion functionality.
Solution Approach 2:
The binder is pre-attached to the graphite particles before electrode fabrication. This preliminary action ensures uniform distribution of binder throughout the electrode structure from the outset, preventing subsequent floating issues during drying and assembly processes.
2Manufacturing precision
If coating and drying processes are adjusted to alleviate binder floating, then binder distribution is improved, but production efficiency is reduced
Solution Approach 1:
The binder is pre-attached to the graphite particles before electrode fabrication. This preliminary action ensures uniform distribution of binder throughout the electrode structure from the outset, preventing subsequent floating issues during drying and assembly processes.
Solution Approach 2:
The patent extracts the binder floating problem by chemically binding the binder to graphite particles, removing the independent binder phase that causes floating. This eliminates the need for complex process adjustments while maintaining uniform distribution.
3Strength
If more binder is added to improve adhesion, then binding force is enhanced, but binder floating and uneven distribution worsen
Solution Approach 1:
The patent combines the binder and graphite particles into a single integrated structure by covalently linking SBR binder molecules to the graphite surface. This merging eliminates the separation between binder and active material, preventing binder floating while maintaining adhesion functionality.
Solution Approach 2:
The patent changes the fundamental parameter of binder-state from free-state to covalently-bound state. This parameter change allows the binder to maintain strong adhesion through chemical bonds while being uniformly distributed throughout the electrode structure.
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 modified graphite achieves even binder distribution, enhances the binding force of the film layer, and improves the storage and cycle performance of the battery without reducing production efficiency.
Implementation Method 1
a binder moiety covalently linked to the graphite moiety
Implementation Method 2
leaving a binder compound to react with graphite in a solvent in the presence of a catalyst
Implementation Method 3
a binder moiety covalently linked to the graphite moiety
Implementation Method 4
help alleviate the problem of floating of the binder in a subsequent process of preparing a negative electrode plate, and in turn, effectively enhance electronic conductivity and adhesion of a film layer
Data Source
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AI summary
This application provides modified graphite and a preparation method thereof, a secondary battery containing the modified graphite, a battery module, a battery pack, and an electrical device. In particular, the modified graphite according to this application includes a graphite moiety and a binder moiety covalently linked to the graphite moiety. The binder moiety possesses a structure expressed as Formula (IV'). The modified graphite according to this application solves the problem that the binder floats up during the preparation of the negative electrode plate of the secondary battery.