Porous Electrode Coating for Uniform Aerosol Charging
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Solution Overview
Problem
Existing electrode production methods via electrostatic coating face low coating efficiency due to non-uniform electric fields and inconsistent powder charging, leading to inefficient adhesion of active material powders onto substrates.
Innovation Solution
A method involving the preparation of an aerosol containing active material powder, binder, and gas, which is electrically charged as it passes through a porous electrode, creating a uniform electric field for enhanced adhesion and using gas flow to select particle size, combined with applying pressure and heat to fix the active material layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If corona discharge is used to charge powder in a non-uniform electric field, then powder adhesion to substrate occurs, but coating efficiency remains low due to non-uniform charging
Solution Approach 1:
Instead of charging powder particles in air using corona discharge, the patent inverts the approach by having particles charge through contact with a porous electrode that has been pre-charged to a specific potential. This reversal of the charging mechanism enables uniform charge distribution across all particles regardless of their position in the electric field.
Solution Approach 2:
The porous electrode serves as an intermediary between the power supply and the powder particles. It receives electrical potential from the power supply and transfers charge to particles through direct contact as they pass through its pores, ensuring uniform charging without requiring uniform electric field distribution in the coating space.
2Productivity
If needle electrode is used to form electric field, then powder can be charged and adhered, but electric field uniformity is poor
Solution Approach 1:
The patent replaces the needle electrode with a porous electrode having numerous through-pores. This porous structure allows powder particles to contact the electrode surface at multiple points while passing through, ensuring uniform charging. The porous geometry also creates a more uniform electric field distribution compared to the concentrated field of a needle electrode.
3Productivity
If powder is sprayed into non-uniform electric field, then adhesion occurs, but coating efficiency is low due to powder loss
Solution Approach 1:
The patent applies preliminary charging action by passing powder particles through the porous electrode before they enter the coating space. This pre-charging ensures that all particles acquire sufficient charge for adhesion before being sprayed, eliminating the need for corona discharge in the coating space and reducing powder loss from inadequate charging.
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
This approach significantly improves coating efficiency by ensuring uniform electrical charging and adhesion of the aerosol particles, resulting in a high-quality active material layer with enhanced peel strength and productivity.
Implementation Method 1
At the time of the aerosol passing through the porous electrode, the aerosol comes into contact with the porous electrode and thereby the aerosol is electrically charged
Implementation Method 2
In the electric field, the aerosol after the electrically charging flies toward the substrate due to electrostatic force. The aerosol adheres to a surface of the substrate
Data Source
AI summary
An aerosol including an active material powder, a binder, and a gas is prepared. An electric field is formed between a substrate and a porous electrode. The aerosol is electrically charged. The aerosol after the electrically charging is introduced into the electric field. The aerosol passes through the porous electrode and thereby the aerosol is introduced into the electric field. At the time of the aerosol passing through the porous electrode, the aerosol comes into contact with the porous electrode and thereby the aerosol is electrically charged. In the electric field, the aerosol after the electrically charging flies toward the substrate due to electrostatic force. The aerosol adheres to a surface of the substrate and thereby an active material layer is formed.