Negative Electrode Plate Optimizing Charge Speed and Energy Density
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Solution Overview
Problem
Current lithium ion secondary batteries face limitations in achieving both high energy density and fast charge capability, often requiring a trade-off between the two, which affects the performance and practicality of new energy vehicles.
Innovation Solution
The design of a lithium ion secondary battery with a negative electrode active material that meets specific conditions regarding particle diameter, orientation index, and degree of graphitization, optimizing the kinetic and energy density parameters to balance fast charge performance and cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the negative electrode active material parameters (particle diameter, orientation index, degree of graphitization) are optimized according to the patent specifications, then fast charge capability is improved, but energy density may be compromised
Solution Approach 1:
The patent applies parameter changes by precisely controlling three key parameters of the negative electrode active material: particle diameter (D50 between 3-15 μm), orientation index (VOI between 5-20), and degree of graphitization (G between 0.85-0.98). By optimizing these parameters within specific ranges, the patent achieves a balance between fast charge capability (improved by smaller particles and higher orientation) and energy density (maintained by controlled particle size and graphitization degree), resolving the technical contradiction between charging speed and energy storage capacity.
2Loss of time
If fast charge capability is enhanced through parameter optimization, then charging time is reduced, but service life may deteriorate
Solution Approach 1:
The patent uses parameter changes to resolve the contradiction between charging time and service life by controlling the particle diameter (D50: 3-15 μm) to prevent both aggregation (which would reduce fast charge capability) and excessive fineness (which would reduce mechanical strength and cycle life). The orientation index (VOI: 5-20) and graphitization degree (G: 0.85-0.98) are also optimized to ensure structural stability during rapid charging cycles, thereby maintaining service life while achieving fast charge capability.
3Quantity of substance
If the negative electrode active material is optimized for high energy density, then energy storage capacity is improved, but fast charge capability is reduced
Solution Approach 1:
The patent resolves this contradiction through parameter changes by establishing specific ranges for particle diameter (D50: 3-15 μm), orientation index (VOI: 5-20), and graphitization degree (G: 0.85-0.98). These parameter optimizations ensure that the negative electrode material has sufficient surface area and structural order for fast ion transport (enabling fast charge) while maintaining adequate material quantity and density (ensuring high energy density), thus achieving both high energy storage capacity and fast charge capability simultaneously.
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 battery achieves improved energy density, fast charge capability, and extended cycle life, ensuring better performance and safety without compromising on energy storage or charging speed.
Implementation Method 1
a negative electrode active material and a negative electrode layer, wherein the negative electrode active material comprises a graphite material
Data Source
AI summary
The disclosure relates to a negative electrode plate and a secondary battery comprising the same. Specifically, the present disclosure provides a negative electrode plate comprising a negative electrode current collector and a negative electrode layer coated on at least one surface of the negative electrode current collector, the negative electrode layer comprising a negative electrode active material, wherein the negative electrode active material comprises a graphite material, and the negative electrode layer fulfills the condition: 0.45 ≤ 7.8/D50 + 1.9*D50/(VOI)2 ≤ 3.1, wherein D50 represents a volume distribution average particle diameter of particles of the negative electrode active material in micron; VOI represents the OI value of the negative electrode layer. The negative electrode plate can allow that a secondary battery containing the same has the combination of high energy density, fast charge, and long cycle life.