Positive Electrode Composition Using Carbon Black Aggregate Control
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Solution Overview
Problem
Existing lithium ion secondary batteries face challenges in achieving low internal resistance and excellent discharge rate and cycle characteristics.
Innovation Solution
A positive electrode composition comprising carbon black, carbon nanotubes, and a binding material, where the carbon black is divided into specific primary aggregates with defined ratios, and the carbon nanotubes have a controlled average diameter and specific surface area, forming a positive electrode with a mixture layer on a current collector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional carbon black is used as conductive material in positive electrode paste, then the manufacturing process is simple, but the battery exhibits high internal resistance and poor discharge rate characteristics
Solution Approach 1:
The invention changes the morphological parameters of carbon black by controlling the formation of primary aggregates with specific X, Y, and Z values. This parameter control transforms conventional carbon black into a structured conductive material that forms efficient conduction networks, thereby reducing internal resistance and improving discharge rate characteristics without complicating the manufacturing process
Solution Approach 2:
The invention creates a composite conductive structure by combining carbon black with specific aggregate morphology (controlled X, Y, Z values) and carbon nanotubes. This composite approach synergistically enhances electrical conductivity and forms a three-dimensional conduction network, resolving the contradiction between simple manufacturing and improved battery performance
2Reliability
If carbon nanotubes with small diameter are used to enhance conductivity, then the electrical conductivity improves, but the manufacturing precision requirements increase
Solution Approach 1:
The invention specifies a particular diameter range for carbon nanotubes (5-15 nm) that optimizes the balance between electrical conductivity and manufacturability. This parameter selection ensures sufficient conductivity enhancement while maintaining feasible manufacturing precision, avoiding the need for ultra-precise control of smaller diameter nanotubes
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 composition results in a battery with low internal resistance and superior discharge rate and cycle characteristics, enhancing conductivity and stability.
Implementation Method 1
a positive electrode composition containing: carbon black; a carbon nanotube... capable of realizing a battery having low internal resistance and excellent discharge rate characteristics
Data Source
AI summary
A positive electrode composition contains carbon black, a carbon nanotube, a binding material, and an active material, in which when the carbon black is divided into a first primary aggregate having an X value of more than 1.7, a second primary aggregate having a Y value of 1.2 or less, a third primary aggregate having a Z value of 2.0 or less, and a fourth primary aggregate having an X value of 1.7 or less, a Y value of more than 1.2, and a Z value of more than 2.0, the number ratio of the total number of the second and third primary aggregates is 22% or more.X=L/WY=P2/4πAZ=(L×W)/AThe primary aggregate has a Feret diameter in the minor axis direction of W (μm), a Feret diameter in the major axis direction of L (μm), a perimeter length of P (μm), and a projected area of A (μm2).