Artificial Graphite Anode Material With Controlled Thermal Expansion
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Solution Overview
Problem
Existing carbon-based negative electrode materials, particularly artificial graphite, face issues with poor electrode adhesion, reduced processability, and degradation of long-term cycle characteristics due to irregular shape and exfoliation, limiting their performance in lithium secondary batteries.
Innovation Solution
A negative electrode active material comprising artificial graphite particles in the form of secondary particles, with a thermal expansion coefficient ranging from 108 × 10 -6< /K to 150 × 10 -6< /K, is developed by bonding primary particles with a pitch binder, optimizing the thermal expansion coefficient through a specific method to improve adhesion and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If artificial graphite is assembled into secondary particles to improve output characteristics, then output characteristics are improved, but electrode adhesion deteriorates and long-term cycle characteristics degrade
Solution Approach 1:
The invention controls the thermal expansion coefficient of artificial graphite particles within a specific range (10-15 × 10^-6/K to 20-15 × 10^-6/K) to resolve the contradiction between output characteristics and electrode adhesion. By adjusting this physical parameter, the graphite particles maintain both high output performance and strong adhesion to the current collector during battery operation.
Solution Approach 2:
The invention uses composite artificial graphite particles formed by aggregating multiple primary particles into secondary particles with controlled structure. This composite structure enables the material to achieve both improved output characteristics through porosity and maintained electrode adhesion through controlled thermal expansion properties.
2Use of energy by moving object
If artificial graphite particles are used to ensure reversibility and high discharge voltage, then energy density is improved, but electrode adhesion and processability deteriorate due to irregular shape
Solution Approach 1:
The invention controls the thermal expansion coefficient of artificial graphite particles within a specific range (10-15 × 10^-6/K to 20-15 × 10^-6/K) to resolve the contradiction between energy density and electrode adhesion. By adjusting this physical parameter, the graphite particles maintain both high energy density performance and strong adhesion to the current collector during battery operation.
3Power
If primary artificial graphite particles are aggregated into secondary particles, then pores are formed to improve output, but shape becomes irregular causing poor adhesion
Solution Approach 1:
The invention controls the thermal expansion coefficient of artificial graphite particles within a specific range (10-15 × 10^-6/K to 20-15 × 10^-6/K) to resolve the contradiction between output characteristics and particle shape regularity. By adjusting this physical parameter, the graphite particles maintain both high output performance through porosity and regular shape for good adhesion.
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 artificial graphite particles enhance electrode adhesion, processability, and initial efficiency while maintaining high capacity and cycle life characteristics, addressing the limitations of conventional carbon-based materials.
Implementation Method 1
a thermal expansion coefficient measured in a temperature range of 30°C to 100°C by a method including the following steps is in a range of 108 × 10^-6/K to 150 × 10^-6/K: (a) mixing the negative electrode active material and a pitch binder in a weight ratio of 90:10
Data Source
AI summary
The present invention provides a negative electrode active material including artificial graphite particle, wherein a thermal expansion coefficient measured by a specific method is in a range of 108 × 10-6/K to 150 × 10-6/K. The negative electrode active material of the present invention has excellent adhesion to an electrode, and has excellent processability and long-term cycle life characteristics accordingly, and the negative electrode including the negative electrode active material has high capacity and excellent initial efficiency.