Precipitation Process for Narrow Particle Distribution
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Solution Overview
Problem
Current processes for producing lithium ion battery cathode materials result in broad particle diameter distributions, which can limit the power rating of lithium ion batteries, and require significant volumes of solvents for precipitation.
Innovation Solution
A process involving the combination of at least two aqueous solutions of salts in a stirred vessel to form sparingly soluble solids, with specific conditions for stirring, separation, and recirculation of mother liquor to achieve a narrow particle diameter distribution of the precipitated solids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional precipitation processes are used to produce cathode materials, then production volume is achieved, but particle diameter distribution becomes broad which limits battery power rating
Solution Approach 1:
The precipitation process is divided into multiple stages with different stirring speeds. A first stirring speed is applied during initial precipitation, then a second, lower stirring speed is applied during subsequent precipitation. This segmentation of the precipitation process into distinct phases with different mechanical conditions enables narrow particle diameter distribution while maintaining high productivity.
Solution Approach 2:
The stirring speed is dynamically adjusted during the precipitation process. The process transitions from a first stirring speed to a second stirring speed, creating varying mechanical conditions that control particle formation. This dynamic adjustment of process parameters enables simultaneous achievement of narrow particle distribution and high production volume.
2Productivity
If conventional precipitation processes are used, then cathode materials can be produced, but significant volumes of solvents are required
Solution Approach 1:
The process utilizes parameter changes in the precipitation environment, specifically pH adjustment through controlled addition of alkali metal hydroxide or ammonium hydroxide. By precisely controlling pH parameters and using recirculation of mother liquor, the process achieves high productivity while minimizing solvent volume requirements.
Solution Approach 2:
The mother liquor from the precipitation process is recirculated back into the precipitation step. This recovery and reuse of mother liquor reduces the total volume of fresh solvent required while maintaining production efficiency, directly addressing the contradiction between productivity and solvent quantity.
3Productivity
If broad particle diameter distribution is accepted, then production volume is maintained, but cathode material properties and battery performance deteriorate
Solution Approach 1:
The precipitation is segmented into multiple steps with varying stirring conditions. The first precipitation step uses one stirring speed while the second precipitation step uses a different stirring speed. This segmentation allows control over particle formation kinetics, achieving narrow particle diameter distribution that maintains both production volume and cathode material properties.
Solution Approach 2:
The precipitation process employs periodic action through controlled addition of precipitating agents and alternating stirring conditions. This periodic variation in process parameters during precipitation enables consistent narrow particle distribution across the entire production batch, maintaining both productivity and material quality.
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 process produces solids with a narrow particle diameter distribution, enhancing the properties of cathode materials and reducing solvent usage, thereby improving the power rating and efficiency of lithium ion batteries.
Implementation Method 1
combining at least two aqueous solutions of salts with one another in a stirred vessel so as to form a sparingly soluble solid
Implementation Method 2
gas is separated off in a first separation apparatus which is selected from liquid-gaseous separation apparatuses
Implementation Method 3
mother liquor is separated off from precipitated sparingly soluble solid in a second separation apparatus selected from solid-liquid separation apparatuses
Data Source
AI summary
Process for producing a suspension by precipitation of a solid from a solution, wherein at least two solutions of salts are combined with one another in a stirred vessel so as to form a sparingly soluble solid, whereportions of suspension are taken off continuously or discontinuously,the portions taken off in this way are processed in a combination of two separation apparatuses, wheregas is separated off in a first separation apparatus which is selected from liquid-gaseous separation apparatuses,and mother liquor is separated off from precipitated sparingly soluble solid in a second separation apparatus selected from solid-liquid separation apparatuses, and the mother liquor is taken off,and the solid which has been separated off or enriched in this way is returned to the reaction mixture.