Cathode Precursor Coprecipitation With Two-Stage Stirring
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Solution Overview
Problem
Conventional batch-type reactors for manufacturing lithium secondary battery positive electrode active material precursors face limitations in reactor size due to motor overload and vibration during high-speed stirring, leading to reduced productivity and issues such as cracks, fines, and abrasion.
Innovation Solution
A two-step coprecipitation process is employed, utilizing a first reactor for high-speed stirring and a second reactor for low-speed stirring, allowing for increased reactor volume and reducing the occurrence of cracks, fines, and abrasion, while maintaining control over reaction conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If a conventional batch-type reactor is used for coprecipitation reaction, then the reactor size is limited, but productivity is significantly reduced
Solution Approach 1:
The coprecipitation reaction process is divided into two distinct stages: a first coprecipitation step in a first reactor and a second coprecipitation step in a second reactor. This segmentation allows each reactor to be optimized for its specific function, enabling the second reactor to be larger in volume for increased productivity while the first reactor handles the initial reaction phase.
2Speed
If high-speed stirring is applied during coprecipitation reaction, then mixing efficiency is improved, but motor overload and vibration occur
Solution Approach 1:
The stirring process is segmented into two stages with different speed requirements. The first coprecipitation step uses high-speed stirring (first stirring speed) for efficient mixing and nucleation, while the second coprecipitation step uses lower-speed stirring (second stirring speed) to avoid motor overload and vibration while still maintaining adequate mixing.
Solution Approach 2:
The stirring speed is dynamically adjusted according to the reaction stage. The system transitions from high-speed stirring in the first reactor to lower-speed stirring in the second reactor, optimizing power consumption and avoiding mechanical limitations while maintaining process effectiveness.
3Productivity
If continuous high-speed stirring is applied during coprecipitation process, then reaction efficiency is improved, but cracks and particle breakage occur
Solution Approach 1:
The coprecipitation process is segmented into two stages with different stirring intensities. The first stage uses high-speed stirring to achieve rapid nucleation and initial particle formation, while the second stage uses lower-speed stirring to complete the coprecipitation without causing excessive mechanical stress that would lead to particle breakage and fines generation.
Solution Approach 2:
The stirring speed is dynamically controlled to match the reaction progress. High-speed stirring is applied only during the initial nucleation phase, then reduced during the growth phase to preserve particle integrity and minimize cracks and abrasion.
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 significantly enhances precursor productivity and improves physical properties by minimizing defects in the precursor, facilitating higher yields and better sphericity and orientation of particles.
Implementation Method 1
a first coprecipitation step of introducing a first transition metal-containing solution, a first chelating agent-containing solution, and a first pH-adjusting agent-containing solution into a first reactor to form a first reaction solution, and performing a coprecipitation reaction
Implementation Method 2
performing a coprecipitation reaction at a first stirring speed; and a second coprecipitation step of transferring the first reaction solution to a second reactor, introducing a second transition metal-containing solution, a second chelating agent-containing solution, and a second pH-adjusting agent-containing solution to form a second reaction solution, and performing a coprecipitation reaction
Data Source
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AI summary
The present invention relates to a method for manufacturing a positive electrode active material precursor for a lithium secondary battery, the method comprising: a first coprecipitation step of introducing a first transition metal-containing solution, a first chelating agent-containing solution, and a first pH-adjusting agent-containing solution into a first reactor to form a first reaction solution, and performing a coprecipitation reaction at a first stirring speed; and a second coprecipitation step of transferring the first reaction solution to a second reactor, introducing a second transition metal-containing solution, a second chelating agent-containing solution, and a second pH-adjusting agent-containing solution to form a second reaction solution, and performing a coprecipitation reaction at a second stirring speed to form a positive electrode active material precursor, wherein the second stirring speed is lower than the first stirring speed.