Continuous Co-precipitation for Uniform Battery Particles
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Solution Overview
Problem
Existing methods for producing size-selected particles, particularly for electrode active materials in secondary batteries, face challenges with particle aggregation, resulting in inconsistent sizes and reduced performance due to varying particle sizes, which affect tap density and cycle life.
Innovation Solution
A continuous co-precipitation method using a combination of continuous stirred tank reactors and centrifugal processing units to produce uniform spherical particles with high tap densities, incorporating post-reactor particle polishing to achieve specific morphologies and sizes, and recycling reagents to minimize waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional continuous stirred tank reactor (CSTR) is used for co-precipitation, then production efficiency is improved, but particle size uniformity deteriorates (varying from nanometers to micrometers)
Solution Approach 1:
The patent divides the particle production process into multiple CSTR stages (first CSTR, second CSTR, third CSTR) with progressively longer residence times. This segmentation allows particles to grow in controlled steps, achieving uniform size distribution (0.5-5 micrometers) while maintaining continuous production efficiency.
Solution Approach 2:
The patent performs preliminary particle formation in the first CSTR with a residence time of 0.5-2 hours before particles enter subsequent reactors. This preliminary action ensures that particles reach a stable size range before further processing, preventing aggregation and ensuring uniformity in the final product.
2Reliability
If tiny particles (less than 500 nm) are produced to increase surface area, then reactivity is improved, but cycle life deteriorates due to side reactions with electrolyte
Solution Approach 1:
The patent controls particle size parameters through residence time adjustment in CSTRs, producing particles in the 0.5-5 micrometer range. This parameter optimization balances surface area (for reactivity) with particle size (to reduce electrolyte side reactions), achieving both high reactivity and long cycle life.
3Quantity of substance
If very large particles (more than 40 μm) are produced, then material yield is improved, but battery performance deteriorates due to coating problems and short circuits
Solution Approach 1:
The patent uses dynamic residence time control in a series of CSTRs to progressively grow particles from nanometer scale to the optimal 0.5-5 micrometer range. This dynamic growth process ensures particles reach the target size without excessive aggregation, maintaining both high yield and battery performance.
4Adaptability or versatility
If batch reactors are used to produce similar particle sizes, then flexibility is improved, but batch-to-batch uniformity deteriorates
Solution Approach 1:
The patent implements continuous flow through a series of CSTRs, maintaining steady-state operation with controlled residence times (0.5-2 hours in first CSTR, 2-8 hours in second, 8-24 hours in third). This continuous action eliminates batch-to-batch variations, ensuring consistent particle size uniformity across all production runs.
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 consistently produces particles with high tap densities, enhancing the energy density of secondary batteries and reducing wastewater production while maintaining product quality and efficiency.
Implementation Method 1
A continuous method for producing size selected particles from a fluid containing both tiny and huge particles is provided.
Implementation Method 2
The particles in the product liquor are contacted with a centrifugal disperser or dispenser and then a particle size separator
Implementation Method 3
The particles in the product liquor are contacted with a centrifugal disperser or dispenser
Implementation Method 4
a particle size separator adapted to separate the particles in the product liquor into a first stream containing particles of a predetermined size and a second stream containing particles of a non-predetermined size
Data Source
AI summary
The invention provides a system for preparing specific sized particles, the system comprising a continuous stir tank reactor adapted to receive reactants; a centrifugal dispenser positioned downstream from the reactor and in fluid communication with the reactor; a particle separator positioned downstream of the dispenser; and a solution stream return conduit positioned between the separator and the reactor. Also provided is a method for preparing specific sized particles, the method comprising introducing reagent into a continuous stir reaction tank and allowing the reagents to react to produce product liquor containing particles; contacting the liquor particles with a centrifugal force for a time sufficient to generate particles of a predetermined size and morphology; and returning unused reagents and particles of a non-predetermined size to the tank.