Natural Graphite Negative Electrode for Higher Initial Charge Power
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Solution Overview
Problem
Energy storage devices require higher initial input power during charging, which is not adequately addressed by existing negative electrode materials and configurations.
Innovation Solution
A negative electrode for energy storage devices is designed with natural graphite particles having an internal porosity of not greater than 2%, an average particle diameter of 6 µm to 10 µm, and a binder content of 0.1% to 2.0% by mass, with a specific particle diameter ratio, ensuring effective binding and conductivity between particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional negative electrode materials are used, then the energy storage device can be manufactured with standard specifications, but the initial input power during charging remains insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle diameter of natural graphite particles (6-10 μm) and the binder content (0.1-2.0% by mass) to optimize the negative electrode structure. These parameter adjustments enable improved initial input power while maintaining manufacturing feasibility, resolving the contradiction between power output and charging rate.
Solution Approach 2:
The patent uses composite materials by combining natural graphite particles with specific binders in optimized ratios. This composite structure enhances both the initial input power and charging rate performance, allowing the negative electrode to simultaneously achieve high power output and high productivity during charging operations.
2Strength
If the binder content is increased to improve particle binding, then the structural integrity of the negative electrode improves, but the initial input power decreases due to reduced conductivity
Solution Approach 1:
The patent applies parameter changes by optimizing the binder content to a specific range (0.1-2.0% by mass). This precise parameter control ensures sufficient binding strength while maintaining adequate conductivity for high initial input power, resolving the contradiction between structural integrity and power output.
Solution Approach 2:
The patent uses natural graphite particles with specific characteristics (particle diameter 6-10 μm, internal porosity not greater than 2%) that naturally provide both binding capability and conductivity. This approach copies the optimal structure from natural graphite to achieve both strong binding and high power output without excessive binder addition.
3Quantity of substance
If larger graphite particles are used to increase capacity, then the energy density improves, but the charging speed decreases due to slower ion diffusion
Solution Approach 1:
The patent applies parameter changes by selecting a specific particle diameter range (6-10 μm) that balances capacity and charging speed. This optimized parameter ensures sufficient ion diffusion rate while maintaining high graphite content for capacity, resolving the contradiction between energy density and charging speed.
Solution Approach 2:
The patent uses natural graphite particles with internal porosity not greater than 2%, which provides sufficient capacity while the controlled porosity allows adequate ion diffusion. This partial optimization of particle structure enables both high capacity and fast charging without requiring excessive particle size reduction.
Data Source
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AI summary
A negative electrode for an energy storage device according to an aspect of the present invention includes a negative electrode active material layer containing natural graphite particles and a binder, wherein the natural graphite particles have an internal porosity of not greater than 2%, the natural graphite particles have an average particle diameter of not less than 6 µm and not greater than 10 µm, the binder in the negative electrode active material layer has a content of not less than 0.1% by mass and not greater than 2.0% by mass, the binder is particulate, and a ratio (B/A) of an average particle diameter B of the binder to an average particle diameter A of the natural graphite particles is not less than 0.015 and not greater than 0.0375.