Negative Electrode Active Material Structure for Flash Charging
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Solution Overview
Problem
Existing lithium-ion batteries have long charging times, which hinder fast charging performance and meet increasing societal demands for quicker charging capabilities.
Innovation Solution
A negative electrode active material with a secondary particle structure formed by binding particulates of specific size and sphericity distributions, achieving a higher sphericity degree and isotropy, thereby shortening lithium ion migration paths for faster intercalation and deintercalation, and utilizing a coating layer to enhance electrical conductivity and binding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional negative electrode materials are used, then the battery structure is simple and easy to manufacture, but the charging time is long and fast charging performance is poor
Solution Approach 1:
The negative electrode active material is segmented into secondary particles, each comprising multiple particulates bound together. This segmentation creates a hierarchical structure where smaller particulates (0.5-5 μm) are grouped into larger secondary particles (5-50 μm), increasing the surface area available for lithium ion intercalation while maintaining manageable particle sizes, thereby reducing charging time without excessive structural complexity
Solution Approach 2:
The patent applies spheroidality by controlling the particulates to have high sphericity (greater than 0.5). Spherical shapes provide isotropic properties that facilitate uniform lithium ion distribution and reduce migration path lengths in all directions. The spherical morphology also improves packing density and electrical contact between particulates, enhancing fast charging performance while maintaining structural simplicity
2Quantity of substance
If larger particle size materials are used, then the electrode density and energy density improve, but the lithium ion migration path becomes longer and charging speed decreases
Solution Approach 1:
The segmentation principle resolves this contradiction by creating secondary particles with controlled internal structure. Each secondary particle contains multiple smaller particulates (0.5-5 μm) that provide short lithium ion migration paths, while the collection of secondary particles (5-50 μm) achieves the desired electrode density. The hierarchical segmentation allows simultaneous optimization of both density and ion transport speed
Solution Approach 2:
Local quality is applied by ensuring that within each secondary particle, the individual particulates maintain specific properties (sphericity > 0.5, size 0.5-5 μm) that optimize lithium ion transport. This local optimization at the particulate level, combined with the overall secondary particle structure, creates regions of high ion conductivity throughout the electrode, enabling fast charging while maintaining high electrode 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 solution enables lithium-ion batteries to achieve fast charging capabilities, known as a 'flash charge' effect, with improved charging rates and energy density, while maintaining discharge capacity and initial efficiency.
Implementation Method 1
the particulates in the secondary particle make a migration path of lithium ions relatively short, so that the lithium ions may be intercalated and deintercalated quickly
Implementation Method 2
utilizing a coating layer to enhance electrical conductivity and binding efficiency
Data Source
AI summary
Disclosed are a negative electrode active material, and a negative electrode plate and a battery including the negative electrode active material. The negative electrode active material of the present disclosure is a secondary particle having a larger particle size and a higher sphericity degree formed from several particulates having smaller particle sizes and lower sphericity degrees. Isotropy of the negative electrode active material is relatively high, and the particulates in the secondary particle make a migration path of lithium ions relatively short, so that the lithium ions can be intercalated and deintercalated quickly, implementing fast charging performance of the battery.