Cathode Precursor Filtration for Uniform Lithium Battery Particles
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Solution Overview
Problem
Existing methods for preparing positive electrode active material precursors for lithium secondary batteries face challenges in achieving uniform particle diameter, shape, and size distribution while maintaining high productivity.
Innovation Solution
A method involving the use of a reactor with a filtration device to continuously concentrate the reaction solution, adding a transition metal-containing solution, an ammonium ion-containing solution, and a basic aqueous solution, while continuously discharging a portion of the reaction solution to maintain a constant increase in solid content concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a continuous stirred tank reactor (CSTR) is used to prepare positive electrode active material precursor, then productivity is improved, but particle size uniformity and shape consistency deteriorate
Solution Approach 1:
The patent applies dynamics by continuously adjusting the solid content concentration during the reaction process. The concentration of solid content is increased at a constant rate from 10% to 60% over time, transforming the static batch process into a dynamic continuous process that maintains optimal reaction conditions throughout, thereby achieving both high productivity and uniform particle characteristics
Solution Approach 2:
The patent changes the parameter of solid content concentration from a fixed value to a continuously varying parameter. By increasing the solid content concentration at a constant rate during the reaction, the system optimizes particle formation dynamics, resulting in uniform particle size distribution and shape while maintaining high productivity
2Manufacturing precision
If a batch-type reactor is used to prepare positive electrode active material precursor, then particle size uniformity is improved, but productivity deteriorates
Solution Approach 1:
The patent implements continuity of useful action by maintaining continuous reaction and continuous discharge of reaction solution throughout the process. The solid content concentration is continuously increased while reaction solution is continuously discharged, eliminating idle time between batches and maintaining productive action throughout the entire process, thereby achieving both high productivity and particle uniformity
3Manufacturing precision
If solid content concentration is continuously increased in the reactor, then particle strength and uniformity are improved, but reaction solution viscosity increases
Solution Approach 1:
The patent applies the extraction principle by continuously removing reaction solution from the reactor as solid content concentration increases. This prevents excessive buildup of viscous reaction solution, maintaining optimal fluidity and mixing conditions throughout the process while still achieving the desired increase in solid content concentration for improved particle characteristics
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 approach results in a positive electrode active material precursor with improved particle strength, uniform particle size distribution, and increased productivity, addressing the limitations of conventional batch-type and continuous stirred tank reactor methods.
Implementation Method 1
a filtration device for separating a reaction solution from the positive electrode active material precursor particles
Implementation Method 2
raw materials are added and co-precipitated
Data Source
AI summary
A method of preparing a positive electrode active material precursor includes forming positive electrode active material precursor particles while adding a reaction solution including a transition metal-containing solution, an ammonium ion-containing solution, and a basic aqueous solution to a reactor with a filtration device installed therein. The method further includes performing continuous concentration in which the reaction solution is added while continuously discharging a portion of the reaction solution in the reactor out of the reactor using the filtration device when the reactor is full, wherein a concentration of a solid content in the reactor is increased at a constant rate.