Negative Electrode Plate with Oriented Flake Graphite
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Solution Overview
Problem
The conventional method for manufacturing negative electrode plates for lithium-ion batteries results in increased internal resistance and higher costs due to the use of a disperse medium, which requires a heating and drying process, and leads to flake graphite particles being predominantly laid sideways, hindering lithium ion insertion and release.
Innovation Solution
A negative electrode plate is formed using a heat-melted binder resin to bind flake graphite particles and the current collecting foil, eliminating the need for a disperse medium and achieving a peak intensity ratio of 130 or less through XRD analysis, allowing for better orientation of graphite particles for improved lithium ion insertion and release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a disperse medium is used in the active material paste, then the flake graphite particles can be easily dispersed and applied, but a heating and drying process is required which lowers productivity and increases cost
Solution Approach 1:
The invention extracts and removes the disperse medium from the active material paste formulation. By using a solvent-free paste composed of flake graphite particles, binder particles, and conductive particles, the patent eliminates the need for heating and drying processes, thereby improving productivity while maintaining ease of application through direct coating methods
Solution Approach 2:
The invention changes the physical and chemical parameters of the paste formulation by removing the disperse medium component. The paste is formulated with specific particle size distributions and compositional ratios that enable direct application without solvents, transforming the manufacturing process from a multi-step drying process to a single-step application process
2Ease of manufacture
If flake graphite particles are placed with basal faces parallel to the current collecting foil, then the active material layer is easy to form, but lithium ion insertion and release are hindered increasing internal resistance
Solution Approach 1:
The invention introduces asymmetry in the orientation distribution of flake graphite particles. Rather than uniform parallel alignment, the paste formulation and application process create a preferential orientation where edge faces are raised at angles, breaking the symmetric parallel arrangement and enabling effective lithium ion pathways while maintaining manufacturability
Solution Approach 2:
The invention changes the orientation parameters of flake graphite particles through controlled paste formulation and application. By adjusting particle size distribution, binder characteristics, and application conditions, the patent achieves a specific orientation state where edge faces are raised, transforming the particle arrangement from a manufactured convenience state to a performance-optimized state
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
This approach enhances productivity, reduces costs, and lowers the internal resistance of lithium-ion batteries by ensuring more edge faces of the flake graphite particles face the surface, facilitating easier lithium ion insertion and release.
Implementation Method 1
the flake graphite particles being bound to one another and the flake graphite particles and the current collecting foil being bound by the heat-melted binder resin
Implementation Method 2
a peak intensity ratio obtained by an XRD analysis being set to be 130 or less
Data Source
AI summary
A negative electrode plate is provided with a current collecting foil and an active material layer. The active material layer formed on the current collecting foil includes flake graphite particles and a binder resin in a manner that the flake graphite particles are bound to one another and the flake graphite particles and the current collecting foil are bound by the heat-melted binder resin, and a peak intensity ratio by an XRD analysis of the active material layer is 130 or less.