Cathode Active Material Precursor Flowability for Uniform Mixing
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Solution Overview
Problem
The existing methods for manufacturing cathode active materials for non-aqueous electrolyte secondary batteries face issues with non-uniform mixing and separation of cathode active material precursors with lithium compounds during the mixing and firing processes, leading to variations in the composition of the final cathode active material.
Innovation Solution
A cathode active material precursor with a flow factor of 10 or greater to 20 and an internal friction angle of 30° to 32° is developed, which facilitates uniform mixing with lithium compounds and inhibits separation, utilizing a crystallization process involving a mixed aqueous solution of metal salts and an ammonium ion supplier, followed by roasting to form a complex metal oxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mixing methods are used for cathode active material precursor and lithium compound, then the mixing process is simple, but the mixing is non-uniform and separation occurs during firing
Solution Approach 1:
The patent changes the physical-chemical parameters of the cathode active material precursor by controlling the crystallization process to achieve specific flowability characteristics (flow factor of 4.0 or more). This parameter change enables uniform mixing with lithium compound without requiring complex mixing equipment or processes, thereby resolving the contradiction between mixing uniformity and process complexity.
2Ease of operation
If cathode active material precursor with poor flowability is used, then the precursor can be obtained through conventional crystallization, but mixing with lithium compound is difficult and separation occurs
Solution Approach 1:
The patent modifies the flowability parameter of the cathode active material precursor through controlled crystallization conditions (temperature, pH, additives), achieving a flow factor of 4.0 or more. This makes the precursor easy to mix with lithium compound while maintaining composition consistency, resolving the contradiction between ease of mixing and manufacturing precision.
3Ease of manufacture
If conventional crystallization conditions are used, then the crystallization process is straightforward, but the flow factor of the resulting precursor is insufficient for uniform mixing
Solution Approach 1:
The patent introduces specific crystallization parameters (temperature range, pH control, use of additives like citric acid or EDTA) that modify the flowability of the resulting precursor without significantly complicating the manufacturing process. These parameter adjustments enable the precursor to achieve a flow factor of 4.0 or more, facilitating easy mixing while maintaining process simplicity.
4Stability of the object's composition
If the flow factor of cathode active material precursor is not controlled, then the precursor can be produced through conventional methods, but separation occurs during the firing process
Solution Approach 1:
The patent establishes specific crystallization parameters that result in a precursor with controlled flow factor of 4.0 or more. This parameter control prevents separation during firing and maintains composition stability, while the control measures remain within conventional manufacturing capabilities, thus resolving the contradiction between composition stability and process control complexity.
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 proposed solution ensures easy and uniform mixing with lithium compounds, preventing separation and resulting in a cathode active material with consistent composition, thereby enhancing the manufacturing process and battery performance.
Implementation Method 1
a crystallization process of adding an alkaline solution to an aqueous mixture of Ni salt and M salt to co-precipitate Ni and M hydroxide
Implementation Method 2
a crystallization process of adding an alkaline solution to an aqueous mixture of Ni salt and M salt to co-precipitate Ni and M hydroxide
Implementation Method 3
a roasting process of roasting the nickel complex hydroxide: Ni x M 1-x (OH) 2 obtained in the crystallization process at a temperature below 800°C in an air atmosphere for one hour or greater to obtain a complex oxide
Data Source
Figure 1A~1B
Figure 2
AI summary
There is provided a cathode active material precursor for a non-aqueous electrolyte secondary battery that is a complex metal hydroxide with a flow factor of 10 or greater to 20 or smaller.