Positive Electrode Slurry Mixing to Suppress Dilatancy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for producing positive electrode mixture slurry in non-aqueous electrolyte secondary batteries fail to effectively suppress dilatancy, leading to issues such as poor applicability, filter clogging, and stagnation in pipelines, while increasing solids concentration is hindered by the likelihood of dilatancy.
Innovation Solution
A method involving three steps of kneading, where greater kinetic energy is applied in the second step after adding a conductive agent and dispersant, and the solids concentration is adjusted to at least 80% in the third step, enhancing the dispersion of the conductive agent and suppressing dilatancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the solids concentration of the slurry is increased to improve producibility, then the productivity is improved, but dilatancy occurs more likely causing poor applicability and pipeline stagnation
Solution Approach 1:
The patent applies parameter changes by controlling the temperature of the slurry during the first kneading step to be between 5°C and 15°C, and by specifying the sequence and conditions of adding materials (dispersant first, then conductive agent). These parameter changes modify the rheological properties of the slurry to suppress dilatancy while maintaining high solids concentration, thereby resolving the contradiction between improved productivity and maintained applicability.
2Productivity
If the solids concentration is increased, then the producibility is improved, but the viscosity increases due to dilatancy causing filter clogging
Solution Approach 1:
The patent applies preliminary action by adding the dispersant to the slurry before adding the conductive agent in the second kneading step. This preliminary action ensures that the dispersant is already present to prevent aggregation of particles when the conductive agent is added, thereby suppressing dilatancy and preventing filter clogging even at high solids concentrations, enabling improved productivity without harmful effects.
3Device complexity
If conventional kneading methods are used, then the production process is simple, but dilatancy occurs leading to stagnation in pipeline
Solution Approach 1:
The patent applies dynamics by specifying different kinetic energy levels for different kneading steps. The second kneading step (after adding conductive agent and dispersant) uses greater kinetic energy compared to the first kneading step. This dynamic adjustment of energy input optimizes the dispersion of conductive agent and suppresses dilatancy, ensuring reliable pipeline flow without significantly complicating the production process.
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 a positive electrode mixture slurry with high solids concentration while effectively suppressing dilatancy, improving producibility and reducing issues like filter clogging and coating defects.
Implementation Method 1
a second kneading step of adding a conductive agent and a dispersant to the first slurry and kneading the mixture
Data Source
AI summary
One example of the method for producing a positive electrode mixture slurry according to the present invention comprises: a first step in which a first slurry is prepared by kneading a positive electrode active material, a binder and a dispersion medium; and a second step in which a second slurry is prepared by adding a conductive agent and a dispersant to the first slurry and kneading the resulting mixture. In the second step, the kinetic energy applied to the slurry is set higher than those in the other steps. The production process of the positive electrode mixture slurry may comprise a third step in which a dispersant is added to the second slurry and the resulting mixture is kneaded.