Electrode Coating With Electrostatic Induction for Binder Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The adhesive force between the active material and the electrode decreases as the loading of the active material increases, leading to a decrease in capacity and cycle lifetime due to solvent volatilization causing binders to concentrate on the surface, affecting uniform chemical reactions and structural stability.
Innovation Solution
An electrode coating apparatus that induces static electricity on the back surface of the electrode current collector with an electrostatic induction unit, using materials like ebonite or nylon, to counteract the charge of the ionic binder in the slurry, preventing binder concentration during drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the amount of polymer binder is increased to improve adhesive force, then the binding strength between active material and current collector increases, but the electrical resistance of the negative electrode increases due to electrical insulation of the binders
Solution Approach 1:
The invention changes the physical state of the binder from a bulk polymer to ultrafine particles (1-100 nm diameter), fundamentally altering its electrical properties while maintaining adhesive functionality. This particle size transformation allows the binder to conduct electricity like active material particles while retaining binding capabilities.
Solution Approach 2:
The invention creates a composite structure where ultrafine binder particles are dispersed among active material particles, forming a conductive network. This composite approach allows both binder and active material to coexist in a manner that maintains electrical continuity while providing mechanical adhesion.
2Quantity of substance
If the loading of active material is increased to achieve higher energy density, then the capacity of the battery increases, but the adhesive force between active material and current collector decreases
Solution Approach 1:
By transforming the binder into ultrafine particles with dimensions comparable to active material particles, the invention enables the binder to be uniformly distributed throughout the electrode structure even at high active material loadings, maintaining adhesive force throughout the electrode thickness.
Solution Approach 2:
The ultrafine binder particles are distributed locally throughout the electrode structure, with each particle providing adhesion at its specific location. This local distribution ensures uniform adhesive force across the entire electrode, preventing delamination even when active material loading is high.
3Stability of the object's composition
If the amount of polymer binder is increased to prevent detachment of active material, then the structural stability improves, but the capacity decreases due to relative decrease in amount of active material
Solution Approach 1:
The invention changes the binder from a continuous phase (consuming significant volume) to a dispersed phase of ultrafine particles (occupying minimal volume). This allows the binder to provide structural stability while occupying such small space that it does not significantly reduce the active material content.
Solution Approach 2:
The invention replaces the traditional mechanical interlocking mechanism of bulk polymer binders with a surface-area-based adhesion mechanism using ultrafine particles. The enormous surface area of nanoscale particles provides strong adhesion through surface forces rather than bulk mechanical properties.
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
Enhances adhesive force and structural stability by maintaining the ionic binders near the electrode surface, improving the electrode's performance and capacity retention.
Implementation Method 1
an electrostatic induction unit to induce static electricity on a back surface of the electrode current collector of which a surface is coated with the electrode slurry
Implementation Method 2
it may induce static electricity by contact charging by coming into contact with the back surface of the electrode current collector of which the surface is coated with the electrode slurry and an electrostatic induction material
Data Source
Figure 1~2(b)
Figure 3
AI summary
The present invention relates to an electrode drying apparatus and a method of manufacturing an electrode using the same, and in the electrode drying apparatus, by inducing static electricity onto a back side of an electrode current collector of which a surface is coated with an electrode slurry so that the electrode slurry has an electric charge opposite to an electric charge of an ionic binder contained in the electrode slurry as a binder, even when solvent volatilization occurs during a drying process of the electrode slurry, it is possible to prevent binders from being moved to a surface of the electrode slurry, and thus it is possible to improve an adhesive force between an electrode mixture layer formed by drying the electrode slurry and the electrode current collector.