Dual-Layer Negative Electrode for Fast-Charging Secondary Batteries
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Solution Overview
Problem
Existing secondary batteries face a challenge in achieving high energy density while maintaining good quick charging performance, as high energy density designs often compromise quick charging capabilities.
Innovation Solution
The secondary battery design incorporates a negative electrode plate with a first negative electrode film and a second negative electrode film, where the first film contains graphite with a particle size uniformity of 0.4 to 0.6, and the second film contains artificial graphite with a particle size uniformity of 0.25 to 0.45, optimizing ion transmission paths and reducing impedance for improved charging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high energy density design is implemented, then energy density is improved, but quick charging performance deteriorates
Solution Approach 1:
The negative electrode film is divided into two distinct layers: a first negative electrode film containing graphite particles with 0.4 to 0.6 uniformity and a second negative electrode film containing artificial graphite particles with 0.25 to 0.45 uniformity. This segmentation allows each layer to serve different functions - the first layer provides high capacity for energy density while the second layer with smaller, more uniform particles facilitates rapid ion transport for quick charging
Solution Approach 2:
Different regions of the negative electrode are assigned different particle size uniformities optimized for their specific functions. The first negative electrode film uses graphite with higher particle size uniformity (0.4-0.6) for capacity, while the second negative electrode film uses artificial graphite with lower particle size uniformity (0.25-0.45) near the collector for rapid charging. This local optimization resolves the contradiction between energy density and quick charging performance
Data Source
AI summary
This application relates to a secondary battery, a process for preparing the same and an apparatus containing the secondary battery. In particular, the negative electrode plate comprises a negative current collector and a negative electrode film, wherein the negative electrode film comprises a first negative electrode film and a second negative electrode film, the first negative electrode film is comprises a first negative electrode active material, and the particle size uniformity of the first negative electrode active material is from 0.4 to 0.6; the second negative electrode film comprises a second negative electrode active material, and the particle size uniformity of the second negative electrode active material is from 0.25 to 0.45, and a ratio of the particle size uniformity of the first negative electrode active material to the particle size uniformity of the second negative electrode active material is from 1.05 to 1.9.