Graphite Negative Electrode Structure for Low-Temperature Input Performance
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Solution Overview
Problem
Energy storage devices face challenges in maintaining high input performance, especially under low temperature environments, due to insufficient charge transport ions and increased reaction resistance caused by high filling rates of negative active material layers in solid graphite electrodes.
Innovation Solution
A negative electrode with a negative active material layer containing solid graphite and carbon fine particles, where the solid graphite has an average circularity of 0.7 or less, enhancing electrolyte retention and reducing side reactions, thereby improving input performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the filling rate of the negative active material layer is increased to improve energy density, then the energy density is improved, but the input performance under low temperature environment deteriorates due to insufficient charge transport ions
Solution Approach 1:
The patent utilizes solid graphite particles with controlled porosity and surface characteristics to create a negative active material layer that maintains both high filling rate and sufficient electrolyte retention. The porous structure of the solid graphite allows electrolyte penetration while maintaining high particle density, resolving the contradiction between energy density and input performance.
Solution Approach 2:
The patent changes the physical and chemical parameters of the carbon fine particles, including particle size distribution, surface area, and surface treatment, to optimize both electrolyte retention and charge transport. By adjusting these parameters, the invention achieves high energy density while maintaining good input performance under low temperature conditions.
2Quantity of substance
If solid graphite with high filling rate is used to improve energy density, then the energy density is improved, but the reaction resistance increases due to insufficient electrolyte supply
Solution Approach 1:
The solid graphite particles are selected and treated to have optimal porosity that allows electrolyte penetration deep into the particle structure. This porous structure ensures sufficient electrolyte supply to the active material even at high filling rates, reducing reaction resistance while maintaining high energy density.
Solution Approach 2:
The patent introduces carbon fine particles as an intermediary material that facilitates electrolyte distribution and charge transport between the solid graphite particles and the electrolyte. This intermediary layer improves electrolyte access to the active material, reducing reaction resistance without compromising energy density.
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 inclusion of carbon fine particles in the negative active material layer ensures sufficient electrolyte retention and reduced reaction resistance, leading to enhanced input performance of energy storage devices even at low temperatures.
Implementation Method 1
the carbon fine particles form a structure, an electrolyte retention property of the negative active material layer can be enhanced
Implementation Method 2
a contact area with the electrolyte is small, so that side reactions and film formation during charging and discharging hardly occur
Implementation Method 3
supply of charge transport ions tends to be insufficient
Data Source
AI summary
A negative electrode according to one aspect of the present invention is a negative electrode for an energy storage device including a negative active material layer containing solid graphite, in which the solid graphite has an average circularity of 0.7 or less, and the negative active material layer further contains carbon fine particles.