Dry Electrode Classification With Mesh Breakage Detection
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Solution Overview
Problem
Existing methods for manufacturing electrodes using slurry-based processes are inefficient in removing specific foreign matter such as magnetic matter and copper, which can adversely affect battery performance, particularly when using powder paints, and the separation efficiency of magnetic separation is not high enough.
Innovation Solution
A method involving dry classification of electrode material using a classifier with a mesh screen, blade, and motor, where breakage of the mesh screen is detected by monitoring operation sound and torque to separate coarse particles effectively, allowing for the production of electrodes with reduced specific foreign matter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If magnetic separation is used to remove magnetic matter from active material powder, then magnetic matter is reduced, but separation efficiency is not high enough because active material particles are also magnetic
Solution Approach 1:
The patent extracts and removes only the non-magnetic foreign matter (such as copper particles) from the active material powder using eddy current separation, while leaving the magnetic active material particles intact. This selective extraction resolves the contradiction by achieving high separation efficiency without affecting the magnetic properties of the desired active material.
Solution Approach 2:
The patent introduces an intermediary substance (conductive liquid or conductive gas) that enables eddy current to be generated in the non-magnetic foreign matter particles. This intermediary facilitates the separation process by allowing electromagnetic interaction with non-magnetic particles without affecting the magnetic active material, thereby achieving high separation efficiency.
2Ease of manufacture
If slurry-based processes are used for electrode manufacturing, then coating can be performed, but specific foreign matter such as magnetic matter and copper cannot be effectively removed
Solution Approach 1:
The patent performs eddy current separation of foreign matter from the active material powder before the coating process. By removing specific foreign matter in advance, the subsequent slurry preparation and coating processes can proceed without contamination, achieving both effective foreign matter removal and proper coating processability.
Solution Approach 2:
The patent segments the electrode manufacturing process into distinct stages: (1) eddy current separation to remove foreign matter from active material powder, (2) slurry preparation using the purified powder, and (3) coating. This segmentation allows each process to be optimized independently, achieving both foreign matter removal and coating quality.
3Loss of substance
If powder paint is used instead of slurry to reduce solvent usage, then manufacturing cost and environmental loads are reduced, but foreign matter separation becomes difficult
Solution Approach 1:
The patent performs eddy current separation to remove foreign matter from the active material powder before mixing it with binder to create powder paint. By eliminating foreign matter in advance, the powder paint can be used without solvent while maintaining low foreign matter content, achieving both reduced solvent usage and effective foreign matter removal.
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 method achieves high separation efficiency of specific foreign matter, stabilizing electrode quality by detecting mesh screen breakage even when the electrode material contains electrically conductive components, resulting in electrodes with low magnetic matter and copper content.
Implementation Method 1
The blade is configured to press the electrode material against the mesh screen
Implementation Method 2
The motor is configured to rotate the blade along an inner peripheral surface of the mesh screen
Implementation Method 3
breakage of the mesh screen is detected by monitoring operation sound and torque
Implementation Method 4
breakage of the mesh screen is detected by monitoring operation sound and torque
Data Source
AI summary
An electrode material containing active material powder is prepared. Dry classification of the electrode material is performed by a classifier. An electrode is manufactured by using the electrode material subjected to the dry classification. The classifier includes a mesh screen, a blade, and a motor. Breakage of the mesh screen is detected by monitoring either or both of an operation sound of the classifier and torque of the motor. The electrode material contained in the classifier will no longer be used for manufacturing of the electrode when breakage of the mesh screen is detected.