Nickel Composite Hydroxide Particle Segmentation for Battery Resistance
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Solution Overview
Problem
Current lithium ion secondary batteries face challenges in achieving uniform particle diameters and high specific surface areas for cathode active materials, leading to increased electrode resistance and reduced battery performance, particularly in nonaqueous electrolyte secondary batteries.
Innovation Solution
The production of nickel composite hydroxide particles with a narrow particle size distribution and a specific structure, involving a nucleation step with controlled pH and a particle growth step to form spherical secondary particles with a central portion and an outer shell portion, followed by heat treatment and calcination to create a lithium nickel composite oxide with a large specific surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If particles with large diameter are used, then manufacturing is easier, but specific surface area decreases leading to increased reaction resistance
Solution Approach 1:
The patent segments particles into two distinct size ranges: first particles with diameter of 0.5 μm or less and second particles with diameter of 1 μm or more. This segmentation allows the electrode to benefit from both fine particles (high specific surface area for low resistance) and coarse particles (easy handling and manufacturing), resolving the contradiction between ease of manufacture and specific surface area requirements.
2Manufacturing precision
If particles with small diameter are used, then specific surface area increases, but reaction resistance increases due to nonuniform voltage distribution
Solution Approach 1:
The patent applies local quality by creating a mixed particle system where different regions of the electrode contain particles of different sizes. The fine first particles provide high specific surface area locally, while the coarse second particles provide structural stability and uniform voltage distribution. This local differentiation allows the electrode to simultaneously achieve low reaction resistance and high reliability.
3Ease of manufacture
If particle size distribution is broad, then manufacturing is easier, but battery capacity decreases due to nonuniform voltage application
Solution Approach 1:
The patent segments the particle size distribution into two distinct populations rather than using a continuous broad distribution. The first particles (0.5 μm or less) and second particles (1 μm or more) are clearly separated in size, which maintains manufacturing ease while ensuring uniform voltage application across the electrode. This segmented approach prevents the capacity loss associated with broad, nonuniform distributions.
4Speed
If thin electrode plates are used, then lithium ion transfer distance is shortened, but manufacturing precision decreases
Solution Approach 1:
The patent applies local quality by using fine first particles (0.5 μm or less) in thin electrode plates. These fine particles provide the necessary particle diameter uniformity and high specific surface area required for thin electrode manufacturing, while simultaneously enabling short lithium ion transfer paths that improve speed. The local use of fine particles resolves the contradiction between speed and manufacturing precision in thin electrode applications.
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 a cathode active material with improved cycle characteristics, reduced electrode resistance, and increased power capacity, enhancing the overall performance of nonaqueous electrolyte secondary batteries.
Implementation Method 1
a) a nucleation step of producing nuclei by controlling a pH of an aqueous solution for nucleation to 11.5 to 13.2
Implementation Method 2
b) a particle growth step of growing the nuclei by controlling a pH of an aqueous solution for particle growth to 9.5 to 11.0
Implementation Method 3
subjecting the nickel composite hydroxide particles to a heat treatment
Implementation Method 4
a calcinating step of calcinating the lithium mixture prepared in the mixing step
Data Source
AI summary
A method for producing nickel composite hydroxide particles may include: a first step of producing nuclei including primary particles by controlling the pH of an aqueous solution for nucleation, the aqueous solution for nucleation containing a metal compound having an atomic ratio of metals corresponding to an atomic ratio of metals in the nickel composite hydroxide particles and substantially not containing a metal complex ion-forming agent; and a second step of forming, on an outer surface of each of the nuclei, an outer shell portion including platy primary particles larger than primary particles of the nuclei by controlling the pH of an aqueous solution for particle growth containing the nuclei obtained in the nucleation step.