Carbon Black Electroconductive Agent for Secondary Cell Surface Coverage
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Solution Overview
Problem
Conventional carbon blacks, such as acetylene black, have large particle diameters that limit their ability to uniformly cover electrode active materials, resulting in inadequate electroconductivity and increased production costs due to excessive solvent absorption and poor dispersion characteristics.
Innovation Solution
A carbon black with primary particle diameters of 15 nm or less and a ratio of primary particles to diameter (PPA/d) between 8 and 12, enhancing the electroconductive effect by optimizing the shape and dispersion of carbon black aggregates for efficient surface coverage of electrode active materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional carbon black with large particle diameter is used, then it is easier to manufacture, but the surface coverage of electrode active material is insufficient and electroconductivity is low
Solution Approach 1:
The invention segments the carbon black aggregate into smaller primary particles (15 nm or less) while maintaining a controlled aggregate structure (PPA/d ratio of 8-12). This segmentation enables better surface coverage of electrode active material particles while preserving the aggregate's ability to disperse uniformly during manufacturing.
Solution Approach 2:
The invention changes the critical parameter of primary particle diameter to 15 nm or less, while controlling the aggregate structure through the PPA/d ratio parameter. This parameter optimization achieves both improved surface coverage and maintained ease of manufacture by balancing particle size with aggregate morphology.
2Reliability
If carbon black with small primary particle diameter is used to improve surface coverage, then electroconductivity improves, but solvent absorption increases and dispersion becomes difficult
Solution Approach 1:
The invention employs a nested structure where small primary particles (15 nm or less) are contained within larger aggregate structures. This nested architecture allows the small particles to provide high electroconductivity and surface coverage while the outer aggregate structure limits excessive solvent absorption and improves dispersion characteristics.
Solution Approach 2:
The carbon black aggregate functions as a composite material combining small primary particles with a controlled aggregate structure. This composite approach enables simultaneous achievement of high electroconductivity (from small particles) and reduced solvent absorption (from aggregate structure).
3Manufacturing precision
If carbon black aggregate with high PPA/d ratio is used, then surface coverage improves, but the aggregate shape becomes less optimal for covering
Solution Approach 1:
The invention optimizes the PPA/d ratio parameter to a specific range (8-12) that balances two competing requirements: high enough to ensure sufficient surface coverage through multiple primary particles, but not so high as to create excessive aggregate complexity that would hinder effective covering of electrode active material.
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 optimized carbon black significantly improves the electric current collection effect, leading to higher energy and output densities, faster charge/discharge capabilities, and reduced production costs, while maintaining high electroconductivity and stability in secondary cells.
Implementation Method 1
The electroconductive agent enhances electroconductivity in an electrode by forming an electroconductive path between individual electrode active material particles
Implementation Method 2
covering the surface of the electrode active material to enhance the electric current collection effect
Data Source
AI summary
The purpose of the present invention is to provide a carbon black capable of efficiently covering the surface of an electrode active material and enhancing the electric current collection effect as an electroconductive agent of a secondary cell. A carbon black comprising carbon black aggregates (2) in which the ratio PPA/d of the number of primary particles (1) (PPA) and the diameter d (nm) of the primary particles (1) is 8 or higher.