Artificial Graphite Anode Particles for Adhesion and Fast Charging
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Solution Overview
Problem
Existing artificial graphite-based negative electrode materials for lithium secondary batteries suffer from poor adhesion and degradation of processability due to irregular shapes, leading to deterioration of long-term cycle characteristics and poor quick charging performance.
Innovation Solution
A method involving the mixing of green coke particles with larger average particle diameters and calcined coke particles with smaller diameters, along with a binder, followed by heat treatment to form bonded secondary particles, enhancing both adhesion and quick charging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sintering is performed in a conventional atmosphere (air or inert gas), then the sintering process can be carried out, but the sintered density becomes insufficient and micro-pores remain in the sintered body
Solution Approach 1:
The patent changes the chemical composition parameter of the sintering atmosphere from conventional air or inert gas to a specific reducing atmosphere containing CO, H2, and N2 in controlled proportions. This parameter change enables sufficient sintered density while removing micro-pores, resolving the contradiction between achieving high density and maintaining process simplicity.
2Reliability
If a specific reducing atmosphere with controlled CO, H2, and N2 proportions is used for sintering, then sintered density and crystalline structure improve, but the sintering process becomes more complex
Solution Approach 1:
The patent uses a reducing atmosphere as an intermediary medium during sintering, which facilitates the formation of a stable crystalline structure and prevents degradation of the negative electrode material. This intermediary atmosphere acts as a mediator between the material particles, enabling reliable crystalline structure formation without requiring overly complex processing equipment.
3Productivity
If sintering is performed without proper atmosphere control, then the process is simple, but Li-ion battery capacity deteriorates and output characteristics worsen
Solution Approach 1:
The patent optimizes the compositional parameters of the sintering atmosphere (CO: 10-50 vol%, H2: 10-50 vol%, N2: 50-80 vol%) to achieve high Li-ion battery capacity and output characteristics. This precise parameter control of the atmosphere composition enables superior battery performance while maintaining a relatively simple sintering system.
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 resulting negative electrode active material exhibits improved adhesion and quick charging capabilities, addressing the limitations of existing materials by optimizing particle size and structure.
Implementation Method 1
a sintering step of sintering the negative electrode mixture
Implementation Method 2
the sintering is performed in a reducing atmosphere
Data Source
AI summary
The present invention relates to a method for preparing a negative electrode active material, which includes mixing green coke particles, calcined coke particles, and a binder, and graphitizing the mixture through heat treatment to form an artificial graphite particle in the form of a secondary particle in which primary artificial graphite particles are bonded to each other, wherein an average particle diameter (D50) of the green coke particles is greater than an average particle diameter (D50) of the calcined coke particles.