Graphite Negative Electrode Material With Uniform Particle Size
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Solution Overview
Problem
Lithium ion secondary batteries face challenges in achieving quick charging performance due to variations in particle size distribution of negative electrode materials, leading to uneven resistance and reduced battery efficiency.
Innovation Solution
A method of manufacturing a negative electrode material involving a mixture of graphitizable aggregate and binder, with a standard deviation of particle size distribution less than 0.20, using coke as the aggregate and pitch, tar, thermoplastic, or thermosetting resin as the binder, and incorporating a dispersant like fatty acid or hydrocarbon to ensure uniform particle size and improved binding properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to manufacture negative electrode material, then production can proceed with standard materials, but the particle size distribution varies significantly leading to uneven resistance and poor quick charging performance
Solution Approach 1:
The patent applies parameter changes by strictly controlling the standard deviation of particle size distribution to be 0.20 or less, and optimizing the binder content to 10-30 parts by mass per 100 parts of aggregate. This precise parameter control ensures uniform particle size and resistance distribution, directly improving quick charging performance while maintaining manufacturing feasibility
Solution Approach 2:
The patent uses composite materials by combining graphitizable aggregate with specific graphitizable binders (pitch, tar, thermoplastic resin, or thermosetting resin) in optimized ratios. This composite approach creates a negative electrode material with improved binding properties and uniform electrical characteristics, resolving the contradiction between manufacturing precision and battery performance reliability
2Strength
If binder content is increased to improve binding properties, then particle adhesion improves, but particle size distribution uniformity deteriorates
Solution Approach 1:
The patent optimizes the binder content parameter to a specific range (10-30 parts by mass per 100 parts of aggregate) to achieve the best balance between binding properties and particle size uniformity. This optimized parameter range ensures sufficient adhesion while maintaining tight particle size distribution control
Solution Approach 2:
The patent introduces dispersants as intermediary substances to facilitate uniform distribution of binder among aggregate particles. The dispersant acts as a mediator that improves binding properties without causing particle size variation, resolving the trade-off between strength and precision
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 method results in a lithium ion secondary battery with enhanced quick charging performance and improved initial charge and discharge efficiency, as well as increased battery life retention, by ensuring uniform resistance distribution and reduced particle size variation.
Implementation Method 1
a step of obtaining a mixture containing a graphitizable aggregate and a graphitizable binder
Implementation Method 2
a step of obtaining a molded product by molding the mixture
Implementation Method 3
a step of obtaining a graphitized product by graphitizing the molded product
Implementation Method 4
a step of obtaining a ground product by grinding the graphitized product
Implementation Method 5
the dispersant includes a hydrocarbon, a fatty acid, a fatty acid metal salt, a fatty acid amide, a fatty acid ester, or a higher alcohol
Data Source
AI summary
A method of manufacturing a negative electrode material for a lithium ion secondary battery, the method includes (a) a step of obtaining a mixture containing a graphitizable aggregate and a graphitizable binder; (b) a step of obtaining a molded product by molding the mixture; (c) a step of obtaining a graphitized product by graphitizing the molded product; and (d) a step of obtaining a ground product by grinding the graphitized product, and a standard deviation of particle size distribution of the aggregate is less than 0.20.