Positive Electrode Precursor Co-Precipitation for Uniform Particle Size
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Solution Overview
Problem
Conventional batch methods for manufacturing positive electrode active material precursors result in uneven particle size distribution and reduced performance due to continuous nucleation during precursor growth, necessitating additional processes that increase costs and decrease production efficiency.
Innovation Solution
Control the co-precipitation reaction conditions by adjusting the feed rate and stirring speed in a batch reactor, specifically using transition metal compound solutions with controlled pH and ammonia concentration, to minimize microparticle formation and achieve uniform particle size distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional batch methods are used for manufacturing positive electrode active material precursor, then the precursor particles can be formed through co-precipitation reaction, but new nucleation reactions continue to occur during growth leading to small-sized precursor particles and uneven particle size distribution
Solution Approach 1:
The patent applies preliminary action by pre-forming a specific number of nuclei before initiating the growth phase. The method involves a two-stage process: first creating a controlled number of nuclei through initial co-precipitation, then adding transition metal compound solution to allow these pre-formed nuclei to grow. This prevents continuous nucleation during growth because the supersaturation is controlled and nuclei are already established, resulting in uniform particle size distribution without sacrificing production efficiency.
2Manufacturing precision
If additional processes such as Air Classifier Mill or cyclone facility are used to remove microparticles, then particle size uniformity can be improved, but costs and total process time increase
Solution Approach 1:
The patent converts the harmful continuous nucleation phenomenon into a beneficial controlled process. Instead of trying to remove microparticles formed during uncontrolled nucleation, the method controls nucleation to form a specific number of nuclei initially, then uses the same co-precipitation reaction conditions to facilitate growth of these pre-formed nuclei. This transforms the problematic continuous nucleation into a controlled two-stage process (nucleation phase followed by growth phase), eliminating the need for additional removal processes and reducing total process time.
3Manufacturing precision
If additional processes such as Air Classifier Mill or cyclone facility are used to remove microparticles, then particle size uniformity can be improved, but equipment complexity and costs increase
Solution Approach 1:
The patent extracts and separates the nucleation and growth phases into distinct sequential steps. By taking out the nucleation phase as a separate initial step where a controlled number of nuclei are formed, and then proceeding to the growth phase where these nuclei are allowed to grow without new nucleation, the method eliminates the need for complex external equipment like Air Classifier Mills or cyclone facilities. The entire process is achieved within the batch reactor through controlled addition of transition metal compound solution.
4Length of moving object
If co-precipitation reaction time is extended to allow microparticle growth, then precursor particles of certain size can be formed, but continuous nucleation occurs leading to smaller particles and uneven distribution
Solution Approach 1:
The patent applies periodic action by dividing the co-precipitation reaction into two distinct periods or stages. The first period involves creating a controlled number of nuclei through initial co-precipitation. The second period involves adding transition metal compound solution and continuing the reaction under controlled conditions to allow growth of the pre-formed nuclei. This periodic approach ensures that nucleation occurs only in the first stage, while the second stage is dedicated to growth, preventing continuous nucleation during the growth period and achieving both desired particle size and uniform distribution.
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 method allows for the rapid production of precursors with targeted particle size and uniform distribution, reducing process time and cost without additional steps, thereby improving production efficiency and battery performance.
Implementation Method 1
there are typically continuous methods using a continuous stirred-tank reactor (CSTR) and batch methods using a batch reactor. The continuous method includes co-precipitating raw materials and simultaneously discharging the particles formed as precursors
Implementation Method 2
as the co-precipitation reaction time progresses, microparticles of the precursor are formed. To form precursor particles of a certain size, it is necessary for the microparticles formed through initial nucleation reactions to continue growing
Data Source
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AI summary
A method for manufacturing a positive electrode active material precursor according the the present disclosure, comprises a first step of creating the nucleus of the precursor; and a second step of growing the nucleus formed in the first step, wherein a transition metal compound solution is fed at a flow rate of 15 mL/min to 55 mL/min into a batch-type reactor during the first step and the second step, wherein a stirring speed inside the reactor during the first step is between 200 rpm and 875 rpm, and a stirring speed inside the reactor during the second step is 475 rpm or less.