Kneading Process for Lithium Ion Battery Electrodes
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Solution Overview
Problem
Existing kneading devices for lithium ion secondary battery electrodes are inadequate for continuous processing and easily damage powders with low wettability due to batch processing and cumbersome condition changes.
Innovation Solution
A process involving a preliminary kneading device that agitates powder and liquid to create a preslurry, followed by a main kneading device with adjustable conical surfaces to uniformly disperse the powder, allowing for stable and continuous kneading with adjustable conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If batch processing is used in existing kneading devices, then all materials can be processed together, but the powder of active material may be damaged and continuous processing is difficult
Solution Approach 1:
The kneading process is divided into two distinct stages: a preliminary kneading stage where thickener and solvent are mixed to form a uniform solution, and a main kneading stage where active material powder is added and processed. This segmentation allows each stage to be optimized independently, enabling continuous processing while protecting the powder from damage by introducing it after the solvent is already prepared.
Solution Approach 2:
The thickener and solvent are mixed and dissolved in advance in the preliminary kneading device before the active material powder is introduced in the main kneading device. This preliminary action ensures that the solvent is ready to properly wet and disperse the powder, preventing powder damage and enabling continuous processing operations.
2Manufacturing precision
If kneading conditions are changed by replacing components, then accurate control is achieved, but the changeover operation becomes cumbersome
Solution Approach 1:
The main kneading device employs an adjustable gap mechanism between the rotor and stator, allowing the kneading conditions to be dynamically changed by adjusting the gap size rather than replacing entire components. This provides precise control over kneading intensity while maintaining ease of operation through simple adjustment procedures.
Solution Approach 2:
Instead of changing physical components to alter kneading conditions, the invention allows modification of operational parameters such as the gap between rotor and stator, rotation speed, and material feed rates. These parameter changes enable precise control of kneading conditions without cumbersome component replacement.
3Device complexity
If thickener, solvent and powder are introduced at once, then processing is simplified, but the powder of active material may be damaged due to low wettability
Solution Approach 1:
The introduction and mixing process is segmented into two stages: first mixing thickener and solvent to create a uniform solution, then separately introducing the active material powder for kneading. This prevents powder damage by ensuring proper wetting conditions exist before powder contact, while the two-stage design remains relatively simple to operate.
Solution Approach 2:
The thickener solution acts as an intermediary between the solvent and the active material powder. By first creating a uniform thickener solution, the system ensures that the powder is properly wetted and dispersed without direct harsh contact with pure solvent, thereby preventing powder damage while maintaining processing simplicity.
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 method prevents powder damage, enables continuous processing, and facilitates easy adjustment of kneading conditions by adjusting the gap between conical surfaces, ensuring thorough wetting and uniform dispersion of the active material with the thickener solution.
Implementation Method 1
adding a thickener to a solvent so as to dissolve the thickener in the solvent by a dissolution device so as to obtain a solution of the thickener as a liquid
Implementation Method 2
passing the preslurry supplied from the preliminary kneading device through the gap so that the powder is uniformly dispersed in the preslurry, the two conical surfaces rotating relative to each other
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A kneading device (1) includes: a preliminary kneading device (4) that produces a preslurry by agitating a powder and a liquid introduced and transferring them while wetting the powder with the liquid; and a main kneading device (5) that causes the powder to be uniformly dispersed in the preslurry supplied from the preliminary kneading device (4) to produce a slurry. The main kneading device (5) includes a gap (G) defined by two conical surfaces that face each other with a predetermined distance therebetween and trotate relative to each other about their central axes. The slurry is produced by passing the preslurry through the gap. With the preliminary kneading device (4), the powder is dispersed in the liquid after conforming to the liquid, which suppress damage to the powder. The conditions of main kneading can be changed only by adjusting the gap (G), which facilitates the operation of changing the conditions of the main kneading.