Carbon Black Composition for Dispersible Low-Viscosity Battery Slurries

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Solution Overview

Problem

Lithium ion secondary batteries face challenges in achieving high conductivity and capacity due to aggregation of conductive agents, leading to poor battery characteristics, particularly when the proportion of conductive agents decreases, resulting in increased slurry viscosity and difficulty in uniform dispersion.

Innovation Solution

Development of carbon black with a specific surface area of 150-400 m2/g and a DBP/CDBP ratio of 2.0 or less, which reduces slurry viscosity and enhances dispersion, allowing for improved conductivity and battery performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the particle size of the conductive agent is decreased to increase the number of particles per unit mass, then the conductivity is improved, but the viscosity of the mixture slurry increases significantly making uniform dispersion difficult

Engineering Contradiction:
ImproveconductivityVSAvoiduniform dispersion
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the structural parameters of carbon black by controlling the DBP absorption ratio (DBP/CDBP ≤ 2.0) and specific surface area (150-400 m²/g), which fundamentally alters how the particles interact in the slurry. This parameter optimization allows small particles to maintain low slurry viscosity while providing sufficient conductivity, resolving the contradiction between improved conductivity and manufacturable dispersion uniformity

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If the proportion of the conductive agent is decreased to increase the proportion of active material, then the capacity is improved, but it becomes difficult to form a conductive path in the electrode

Engineering Contradiction:
Improveactive material proportionVSAvoidconductive path formation
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

By optimizing the carbon black structure parameters (specific surface area and DBP absorption ratio), the patent enhances the conductivity efficiency per unit mass. This allows the conductive agent to form effective conductive paths at lower proportions, enabling higher active material content while maintaining reliable conductivity throughout the electrode

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the structure of carbon black is developed to efficiently form a conductive path, then the conductivity is improved, but the dispersion state deteriorates if the particle size decreases

Engineering Contradiction:
Improveconductive path formationVSAvoiddispersion state
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent optimizes the structural development of carbon black by controlling the DBP absorption ratio and specific surface area, creating a balanced structure that provides both conductive path formation capability and good dispersion stability. The controlled structural development prevents excessive entanglement while maintaining conductivity efficiency

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20240021834A1Carbon black, slurry, and lithium ion secondary battery
Publication Date: 2024.01.18 DENKA CO LTD

AI summary

Carbon black having a specific surface area of 150 m2/g or more and 400 m2/g or less, and a ratio (DBP/CDBP) of a DBP absorption (DBP) to a compressed DBP absorption (CDBP) of 2.0 or less.