Nickel Composite Hydroxide Crystallization for High Tap Density
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Solution Overview
Problem
Current methods for producing nickel composite hydroxide as a precursor for cathode active materials in non-aqueous electrolyte secondary batteries face challenges in achieving uniform particle size and high packing density, leading to suboptimal battery capacity and coulomb efficiency, while also being inefficient in terms of productivity.
Innovation Solution
A method involving a two-stage crystallization process is employed, where the initial particle size is controlled in the primary crystallization stage, and further growth occurs in the secondary stage with continuous removal of the liquid component, using a cross-flow filtering apparatus to maintain slurry concentration and achieve particles with a narrow size distribution and high tap density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If particle size is increased to improve packing density, then battery capacity increases, but particles larger than 50 μm cause filter clogging and lineation defects
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size distribution parameters (D10, D50, D90 values) to achieve optimal packing density while avoiding the harmful effects of oversized particles. The particle size distribution is controlled within specific ranges to resolve the contradiction between maximizing packing and preventing defects.
2Quantity of substance
If particle size distribution is widened to improve packing characteristic, then packing density increases, but voltage becomes uneven and minute particles deteriorate selectively
Solution Approach 1:
The patent controls the particle size distribution parameters (D10, D50, D90) within specific ranges to achieve optimal packing while maintaining voltage uniformity and preventing selective deterioration of minute particles during charging and discharging cycles.
3Manufacturing precision
If batch crystallization is used to achieve sharp particle size distribution, then particle uniformity improves, but productivity decreases compared to continuous method
Solution Approach 1:
The patent segments the crystallization process into two distinct stages: primary crystallization to control particle size distribution and secondary crystallization to achieve final particle characteristics. This segmentation allows each stage to be optimized independently, resolving the contradiction between precision and productivity.
Solution Approach 2:
The primary crystallization stage performs preliminary action by establishing the particle size distribution early in the process, creating a foundation for the secondary stage to refine and finalize the particle characteristics without starting from scratch.
4Quantity of substance
If particle size is made moderately large with sharp distribution for high capacity, then battery capacity improves, but achieving this requires complex control of crystallization parameters
Solution Approach 1:
The crystallization process is divided into two stages with distinct objectives and control parameters, making the complex task of achieving moderate large particle size with sharp distribution more manageable through systematic breakdown of control requirements.
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 nickel composite hydroxide with uniform particle size and high packing density, enhancing battery capacity and coulomb efficiency while maintaining high productivity, making it suitable for industrial production.
Implementation Method 1
a cross-flow filtering apparatus to maintain slurry concentration
Implementation Method 2
a two-stage crystallization process is employed
Implementation Method 3
performing a crystallization reaction
Data Source
Figure 1~2
Figure 3~4
AI summary
Provided is a cathode active material for a non-aqueous electrolyte secondary battery that has a uniform particle size and high packing density, and that is capable of increased battery capacity and improved coulomb efficiency. When producing a nickel composite hydroxide that is a precursor to the cathode active material by supplying an aqueous solution that includes at least a nickel salt, a neutralizing agent and a complexing agent into a reaction vessel while stirring and performing a crystallization reaction, a nickel composite hydroxide slurry is obtained while controlling the ratio of the average particle size per volume of secondary particles of nickel composite hydroxide that is generated inside the reaction vessel with respect to the average particle size per volume of secondary particles of nickel composite hydroxide that is finally obtained so as to be 0.2 to 0.6, after which, while keeping the amount of slurry constant and continuously removing only the liquid component, the crystallization reaction is continued until the average particle size per volume of secondary particles of the nickel composite hydroxide becomes 8.0 µm to 50.0 µm.