Ternary Precursor Preparation via Staged EDCF Control
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Solution Overview
Problem
Current methods for preparing ternary precursors for lithium ion batteries face challenges with uneven particle size distribution and cracking, leading to suboptimal electrochemical performance and cycle life, due to inadequate control over macro/micro shear and mixing environments in the reactor.
Innovation Solution
A preparation method and device utilizing a mixed flow disc turbine impeller with a larger impeller diameter ratio and reasonable layer spacing to achieve uniform distribution and controlled shear action, ensuring a narrower particle size distribution and preventing cracking, by regulating the energy dissipation circulation function (EDCF) and adjusting the stirring parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional preparation methods are used to produce ternary precursor, then production capacity is achieved, but particle size distribution becomes uneven and cracking occurs
Solution Approach 1:
The patent applies dynamic control of stirring speed throughout the precipitation process. The stirring speed is adjusted in stages: initially at 800-1200 rpm during nucleation, then reduced to 400-600 rpm during crystal growth, and finally increased to 1000-1400 rpm during aging. This dynamic adjustment optimizes both particle size uniformity and prevents cracking while maintaining production capacity.
Solution Approach 2:
The patent systematically changes multiple process parameters including pH value (controlled at 10.5-12.5), temperature (40-70°C), ammonia concentration (2.0-12 g/L), and stirring speed at different stages. These parameter changes enable precise control over particle size distribution and crystal structure, achieving narrow span (0.2-0.8) without cracking.
2Manufacturing precision
If stirring speed is increased to improve mixing uniformity, then particle size distribution narrows, but crystal particle cracking increases
Solution Approach 1:
The patent employs periodic action through multi-stage stirring speed adjustment and aging treatment. The process includes initial rapid stirring for nucleation, followed by reduced stirring for crystal growth, and final high-speed stirring during aging. This periodic variation in stirring intensity ensures uniform particle size while the aging stage allows stress relief, preventing crystal cracking.
Solution Approach 2:
The patent applies preliminary action through pre-cooling of reactant solutions and controlled nucleation conditions before the main precipitation reaction. By preparing the system in advance with appropriate temperature and concentration conditions, uniform nuclei are formed that grow into evenly sized particles without excessive stress that would cause cracking.
3Productivity
If reactor volume is increased for large-scale production, then productivity improves, but mixing and shear control becomes inadequate
Solution Approach 1:
The patent segments the precipitation process into distinct stages (nucleation, crystal growth, and aging) with specific control parameters for each stage. This segmentation allows the same reactor to achieve precise control at different times, enabling large-scale production while maintaining uniform particle size distribution and appropriate shear conditions throughout the process.
Solution Approach 2:
The patent makes the stirring system universal by designing it to perform multiple functions: initial rapid mixing for nucleation, gentle stirring for crystal growth, and final high-speed stirring for aging. This multi-functional stirring approach allows a single reactor configuration to maintain precise control over mixing and shear environments regardless of scale.
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 achieves a ternary precursor with a concentrated particle size distribution, higher compaction density, and uniform appearance without cracking, enhancing the electrochemical performance and cycle life of lithium ion battery positive electrodes.
Implementation Method 1
controlling a macro/micro shear action circulation function
Implementation Method 2
mixed flow disc turbine impeller with a larger impeller diameter ratio and reasonable layer spacing to achieve uniform distribution and controlled shear action
Implementation Method 3
A coprecipitation method of the ternary precursor is based on precipitation reaction crystallization
Implementation Method 4
undergo the process of crystal nucleus formation, crystal nucleus growth, etc. to generate nickel cobalt manganese hydroxide precipitation
Data Source
AI summary
A ternary precursor of a lithium ion battery as well as a preparation method and preparation device thereof are provided. A chemical general formula of the ternary precursor is NixCoyMnz(OH)2, 0.5≤x≤0.9, 0.05≤y≤0.3, and x+y+z=1. A particle size D50 of a large-particle ternary precursor is 10.0-16.0 μm, a particle size D50 of a small-particle ternary precursor is 3.0-6.0 μm, and a span is 0.2-0.8. A nucleation and growth process of a crystal is regulated through a staged EDCF, a crystal particle size meeting specific requirements and compact particles without a cracking phenomenon can be obtained. A disc, inclined blades and an arc surface are combined, and an arc-shaped curved surface can effectively reduce a turbulence energy dissipation rate of a local area.