Slurry Filter Clogging Prediction via Rheological Shear Analysis
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Solution Overview
Problem
The increasing use of artificial graphite in lithium secondary battery manufacturing leads to filter clogging issues during the coating process due to shear-induced gelation, causing processability problems and a lack of effective methods for evaluation and prevention.
Innovation Solution
A method to evaluate filter clogging by calculating shear rate, measuring phase angle (δ) and crossover frequency before and after applying shear to the slurry, determining filter clogging based on significant changes in these rheological properties, allowing for prediction and prevention of coagulation and clogging without direct filtration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If artificial graphite is used as negative electrode active material to prevent swelling, then electrode stability is improved, but filter clogging occurs due to shear-induced gelation
Solution Approach 1:
The patent applies preliminary shear treatment to the slurry before filtration to induce gelation in advance. By pre-applying shear stress equivalent to what would occur during filtration, the slurry's gelation behavior is activated beforehand, allowing the formation of a stable gel structure that prevents clogging during actual filter operation
Solution Approach 2:
The patent changes the rheological parameters of the slurry by applying controlled shear stress. This transforms the slurry from a non-gelated state to a gelated state with modified viscosity and flow properties, enabling it to pass through filters without clogging while maintaining electrode stability
2Manufacturing precision
If artificial graphite slurry is filtered to remove large particles, then coating quality is improved, but processability deteriorates due to shear-induced gelation
Solution Approach 1:
The patent performs preliminary shear treatment before filtration to pre-activate the gelation mechanism. This allows the slurry to maintain proper flow characteristics during filtration and coating processes, preventing the deterioration of processability that would otherwise occur due to shear-induced gelation
Solution Approach 2:
The patent enables the slurry to rapidly pass through the filter by pre-modifying its rheological properties. The controlled shear treatment creates a gel structure that allows the slurry to flow more easily through the filter medium, skipping the clogging issue that would normally occur
3Quantity of substance
If slurry is directly filtered during coating, then particle removal is achieved, but evaluation of clogging tendency is not possible
Solution Approach 1:
The patent replaces direct mechanical filtration with a rheological evaluation method. By measuring viscosity changes and gelation behavior under controlled shear conditions, the system can predict clogging tendency without actually performing filtration, thus enabling evaluation while maintaining particle removal capability
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 improves the efficiency of battery manufacturing by predicting and evaluating filter clogging, enhancing process control and reducing the likelihood of clogging, thus maintaining consistent production.
Implementation Method 1
the occurrence of the filter clogging issue is caused by shear-induced gelation of the artificial graphite
Implementation Method 2
measuring rheological properties, for example, viscosity, phase angle (δ) and crossover frequency, of slurry
Data Source
AI summary
A method for predicting the likelihood of coagulation of active material particles contained in a slurry for electrode preparation includes measuring rheological properties before and after the slurry is subjected to a shear. The estimation method enables a prediction of filter clogging with a slurry, and thus makes it possible to estimate the likelihood of filter clogging with a slurry without passing the slurry directly through the filter, thereby improving the efficiency of a battery manufacturing process.