Dual-Coated Graphite Negative Electrode for Fast Charging and Cycle Life
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Solution Overview
Problem
Secondary batteries face challenges in achieving both high energy density and good quick charging performance and cycle life, as increasing energy density often compromises power performance and service life.
Innovation Solution
A secondary battery design featuring a negative electrode plate with a dual coating structure, where the first negative electrode film comprises primary particles of artificial graphite with a percentage ≥50% and the second film comprises secondary particles of artificial graphite with a percentage ≥30%, enhancing contact area and electron conduction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the energy density of secondary battery is increased, then the energy storage capacity is improved, but the power performance and service life deteriorate
Solution Approach 1:
The negative electrode film is divided into two distinct layers: a first negative electrode film containing primary particles and a second negative electrode film containing secondary particles. This segmentation allows each layer to perform specialized functions - the first layer provides high capacity while the second layer ensures good contact and conductivity, thus resolving the contradiction between energy density and power performance
Solution Approach 2:
Different regions of the negative electrode are given different properties through the dual-layer structure. The first negative electrode film is designed with primary particles for high capacity storage, while the second negative electrode film uses secondary particles to ensure good contact area and electron conduction. This local differentiation allows the battery to achieve both high energy density and good power performance simultaneously
Data Source
AI summary
The present application relates to a secondary battery, a process for preparing the same and an apparatus containing the secondary battery. Particularly, the secondary battery comprises a negative electrode plate, wherein the negative electrode plate comprises a negative electrode current collector and a negative electrode film, and the negative electrode film comprises a first negative electrode film and a second negative electrode film; the first negative electrode film is disposed on at least one surface of the negative electrode current collector and comprises a first negative electrode active material; and the second negative electrode film is disposed on the first negative electrode film and comprises a second negative electrode active material; the first and second negative electrode active materials both comprise artificial graphite; the first negative electrode active material comprises primary particles, and a number percentage of the primary particles in the first negative electrode active material A satisfies A≥50%.