Negative Electrode Active Surface Area Control for Fast Charging
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Solution Overview
Problem
Current fast-charging batteries face limitations in energy density and dynamics performance due to the use of lithium titanate and amorphous carbon as negative active materials, which hinder rapid charging capabilities and cycle life.
Innovation Solution
A battery design featuring a negative electrode plate with a specific surface area of 1-15 cm^2/g, porosity of 25-40%, and a coating weight of 6.8-9.2 mg/cm^2, utilizing graphite as the negative active material, along with a testing method using cyclic voltammetry to determine active specific surface area, optimizing the electrode structure for enhanced charge exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If lithium titanate and amorphous carbon are used as negative active materials to improve fast charging capability, then rate performance is improved, but energy density decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the active specific surface area of the negative electrode plate within 1-15 cm²/g, porosity within 25-40%, and coating weight within 6.8-9.2 mg/cm². These parameter optimizations enable graphite to achieve both fast charging capability and high energy density, resolving the contradiction between charging speed and energy density
Solution Approach 2:
The patent uses graphite as the negative active material with optimized composite structure including specific porosity and coating weight parameters. This composite material approach allows the negative electrode to achieve both high rate performance and high energy density, overcoming the limitations of single-material solutions like lithium titanate or amorphous carbon
2Speed
If high current charging is applied to improve charging rate, then charging speed is improved, but lithium metal precipitation occurs on the negative electrode plate
Solution Approach 1:
The patent controls the active specific surface area of the negative electrode plate within 1-15 cm²/g, which optimizes the charge exchange speed and prevents lithium metal precipitation during high current charging. This parameter optimization allows the battery to achieve fast charging capability while maintaining cycle life and safety performance
Solution Approach 2:
The patent employs a testing method using cyclic voltammetry to measure the active specific surface area of the negative electrode plate. This feedback mechanism allows for precise control and optimization of the electrode structure to prevent lithium precipitation while maintaining fast charging capability
3Speed
If high current charging is applied to improve charging rate, then charging speed is improved, but side-products are generated on the surface of the negative electrode plate
Solution Approach 1:
The patent optimizes the active specific surface area of the negative electrode plate within 1-15 cm²/g and porosity within 25-40%, which harmonizes the chemical system and reduces side reactions during fast charging. These parameter changes minimize side-product generation while maintaining high charging rates
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 battery achieves high energy density and excellent dynamics performance by controlling the active specific surface area of the negative electrode plate, enabling faster charge exchange and reducing side reactions, thus improving the lithium-ion battery's charging speed and cycle life.
Implementation Method 1
a core of the fast charging technology of the battery is how to improve the tranferring speed of the lithium ions between the positive electrode plate and the negative electrode plate by harmonizing the chemical system
Implementation Method 2
a testing method of an active specific surface area of an electrode plate... step (2) a series of cyclic voltammetry curves under a series of scanning rates v of the button half battery are obtained on an electrochemical workstation
Data Source
AI summary
The present invention provides a battery and a testing method of an active specific surface area of an electrode plate. The battery comprises a positive electrode plate, a negative electrode plate, a separator and an electrolyte, the negative electrode plate comprises a negative current collector and a negative film, the negative film is provided on at least one surface of the negative current collector and comprises a negative active material, the negative active material comprises graphite, and an active specific surface area of the negative electrode plate is 1 cm2/g∼15 cm2/g. In the present invention, by reasonably controlling the active specific surface area of the negative electrode plate can make the battery have the characteristics of high energy density and excellent dynamics performance at the same time.