Nickel Hydroxide Precursor Particle Sizing for Initial Battery Efficiency
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Solution Overview
Problem
Existing cathode active materials for non-aqueous electrolyte secondary batteries, such as those described in International Publication No. WO 2018-020845, do not achieve optimal initial charge-discharge efficiency, necessitating further improvements.
Innovation Solution
A nickel-containing hydroxide is produced as secondary particles formed by agglomerating primary particles with an average area of 0.035 μm² or more, and a method involving controlled flow rates of metal-containing aqueous solutions in the production process to adjust primary particle size, resulting in a cathode active material with enhanced initial charge-discharge efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the primary particles are made smaller to increase surface area, then the battery capacity may improve, but the initial charge-discharge efficiency deteriorates
Solution Approach 1:
The patent changes the critical parameter of primary particle area from being small (comparative example with 0.030 μm²) to being 0.035 μm² or more. This parameter change resolves the contradiction by finding the optimal size threshold that maintains high initial charge-discharge efficiency while still providing sufficient surface area for battery capacity.
Solution Approach 2:
The patent establishes a dynamic lower bound (0.035 μm²) rather than a fixed small size, allowing flexibility in particle size optimization. This enables the system to adapt between surface area benefits and efficiency requirements by adjusting particle size within the specified range.
2Productivity
If the flow rate of metal-containing aqueous solution is increased to improve productivity, then the production efficiency improves, but the primary particle area decreases below the optimal range
Solution Approach 1:
The patent identifies flow rate as a critical process parameter that directly affects primary particle area. By establishing the threshold of 0.25 m/s or less, the patent changes the operating parameter to simultaneously achieve acceptable productivity while maintaining primary particle area at 0.035 μm² or more for high initial charge-discharge efficiency.
Solution Approach 2:
The patent establishes a feedback mechanism where the flow rate is controlled based on its impact on primary particle area, which in turn affects initial charge-discharge efficiency. This closed-loop control ensures that productivity improvements do not compromise the critical particle size requirement.
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 produces a cathode active material that enhances the initial charge-discharge efficiency of non-aqueous electrolyte secondary batteries, improving their performance in devices requiring high energy density and rapid charging capabilities.
Implementation Method 1
the nickel-containing hydroxide is secondary particles formed by agglomeration of a plurality of primary particles
Implementation Method 2
a flow rate of the metal-containing aqueous solution containing nickel supplied to the reaction tank in the reaction step is 0.25 m/s or less
Data Source
AI summary
Provided is a nickel-containing hydroxide as a precursor of a cathode active material for a non-aqueous electrolyte secondary battery, wherein the nickel-containing hydroxide is secondary particles formed by agglomeration of a plurality of primary particles, and the primary particles have an average area of 0.035 μm2 or more.