Cathode Precursor Particle Distribution for Low-Impurity Li-Ion Cells
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Solution Overview
Problem
Existing lithium secondary battery positive electrode active materials have room for improvement in battery characteristics due to impurities and unsuitable particle size distributions.
Innovation Solution
A precursor for lithium secondary battery positive electrode active materials with a specific particle size distribution and low impurity content, particularly silicon, is developed. This precursor is produced using a method that includes slurry preparation, classification, and calcination, ensuring a narrow particle size distribution and minimal impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a precursor with narrow particle size distribution is used, then battery characteristics are improved, but impurity content increases
Solution Approach 1:
The patent applies segmentation by dividing the particle size distribution into multiple controlled ranges (D10-D30, D30-D50, D50-D70, D70-D90) with specific cumulative volume percentages. This segmented approach allows precise control over particle sizes while maintaining narrow overall distribution, thereby improving battery characteristics without compromising purity.
Solution Approach 2:
The patent utilizes parameter changes by precisely controlling the particle size distribution parameters (D10, D30, D50, D70, D90 values and their relationships) of the precursor particles. By adjusting these distribution parameters within specific ranges, the invention achieves optimal battery performance while preventing impurity formation.
2Stability of the object's composition
If particle size distribution is optimized, then voltage uniformity improves, but manufacturing complexity increases
Solution Approach 1:
The patent achieves voltage uniformity by controlling specific particle size distribution parameters (D10-D30 ratio, D30-D50 ratio, D50-D70 ratio, D70-D90 ratio all within 0.20-0.80 ranges). This parameter-based control provides a straightforward manufacturing approach that ensures consistent voltage characteristics without requiring complex processing equipment or procedures.
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 use of this precursor leads to improved battery characteristics, including enhanced cycle retention and reduced variability in charging and discharging loads, due to its optimized particle size distribution and low impurity content.
Implementation Method 1
a laser diffraction-type particle size distribution measuring instrument
Data Source
AI summary
A precursor for lithium secondary battery positive electrode active materials containing at least nickel, in which the following formula (1) is satisfied.0.20 ≤Dmin/Dmax (1)(in the formula (1), Dmin is a minimum particle diameter (μm) in a cumulative particle size distribution curve obtained by measuring the precursor for lithium secondary battery positive electrode active materials with a laser diffraction-type particle size distribution measuring instrument, and Dmax is a maximum particle diameter (μm) in the cumulative particle size distribution curve obtained by the measurement with the laser diffraction-type particle size distribution measuring instrument.)