Double-Coated Battery Anode for Fast Charging and Cycle Stability
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Solution Overview
Problem
Existing secondary batteries face challenges in achieving good electrochemical performance and safety performance while maintaining high energy density.
Innovation Solution
A secondary battery design featuring a negative electrode plate with a double-coating structure, where both the first and second negative electrode coating layers include specific active materials, including graphite and artificial graphite with controlled silicon-based material percentages, optimizing the electrode structure for improved ion transmission and volume stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer negative electrode coating structure is used, then the device complexity is low, but the fast charging capability and cycle performance are insufficient
Solution Approach 1:
The negative electrode coating is divided into two distinct layers: a first negative electrode coating layer containing graphite and silicon-based material, and a second negative electrode coating layer containing artificial graphite and silicon-based material. This segmentation allows each layer to perform specific functions, improving fast charging capability and cycle performance while managing the complexity through a systematic multi-layer architecture.
Solution Approach 2:
Different regions of the negative electrode are assigned different material compositions and silicon-based material percentages. The first coating layer has a specific silicon-based material content, while the second coating layer has a different silicon-based material content, creating local quality variations that optimize performance for specific functions such as initial lithium insertion and overall structural stability.
2Quantity of substance
If high silicon-based material content is used to increase energy density, then the energy density improves, but lithium precipitation and safety issues worsen
Solution Approach 1:
The silicon-based material is distributed non-uniformly across the two coating layers, with different percentages in each layer. This local quality approach allows high silicon content in specific regions to boost energy density while maintaining lower silicon content in other regions to prevent lithium precipitation and ensure safety.
Solution Approach 2:
The negative electrode uses composite material structures combining graphite, artificial graphite, and silicon-based materials in specific ratios within each coating layer. This composite approach balances energy density enhancement from silicon with the structural stability and safety provided by graphite components.
3Quantity of substance
If high energy density is pursued, then the energy capacity increases, but electrochemical performance and safety performance deteriorate
Solution Approach 1:
The electrode structure is segmented into two coating layers with different material compositions, allowing the system to achieve high energy capacity through silicon-based materials while maintaining good electrochemical performance through the distributed architecture that facilitates ion transport and electron conduction.
Solution Approach 2:
Composite materials comprising graphite, artificial graphite, and silicon-based materials are used in specific combinations within each coating layer. This composite material strategy enables the simultaneous achievement of high energy capacity and good electrochemical performance by balancing the high-capacity silicon with the conductive and stable graphite components.
Data Source
AI summary
The present application discloses a secondary battery, a process for preparing the same, and an apparatus including the secondary battery. The secondary battery includes a negative electrode plate, and the negative electrode plate includes a negative electrode current collector and a negative electrode film; the negative electrode film includes a first negative electrode coating layer and a second negative electrode coating layer; the first negative electrode coating layer is disposed on at least one surface of the negative electrode current collector and includes a first negative electrode active material, the first negative electrode active material includes graphite; the second negative electrode coating layer is disposed on a surface of the first negative electrode coating layer and includes a second negative electrode active material, and the second negative electrode active material includes artificial graphite and a silicon-based material.