Negative Electrode Surface Layer for Rapid Lithium Charging
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Solution Overview
Problem
Lithium secondary batteries for electric vehicles face challenges in achieving rapid charging without compromising energy density or increasing manufacturing costs, as existing methods often lead to electrode deterioration and inefficient rapid discharging.
Innovation Solution
A negative electrode with a surface layer of insulating particles, such as Al2O3 or ZnO, applied using vapor deposition or coating, which shields the electrode material and reduces electric field concentration, thereby enhancing charging speed while maintaining energy density and reducing manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the electrode plate is made thin or loading level is reduced to achieve rapid charging, then rapid charging characteristics are improved, but energy density decreases
Solution Approach 1:
The invention applies a surface layer with insulating particles specifically on the negative electrode material layer surface, creating local functional differentiation. This allows the bulk electrode to maintain high loading for energy density while the surface provides rapid charging capability through controlled ion distribution, resolving the contradiction between thin electrode requirements for fast charging and high loading requirements for energy density.
2Speed
If surface treatment or porous structure is introduced to enhance rapid charging, then rapid charging characteristics are improved, but initial efficiency deteriorates or energy density decreases
Solution Approach 1:
The invention creates a composite structure by combining the negative electrode active material particles with a surface layer containing insulating particles. This composite approach allows the core active material to maintain high initial efficiency while the insulating particle-containing surface layer enhances rapid charging characteristics, avoiding the efficiency loss associated with conventional surface treatments.
3Speed
If conventional surface treatment methods are used to improve rapid charging, then rapid charging is enhanced, but manufacturing cost increases due to complicated process
Solution Approach 1:
The invention changes the key parameter of the electrode surface by introducing insulating particles into the surface layer, rather than using complex chemical surface treatments or porous structure modifications. This parameter change approach achieves rapid charging enhancement through a simpler manufacturing process, reducing both process complexity and manufacturing cost while maintaining the desired rapid charging performance.
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 high-speed charging without lifetime degradation, improves cycle lifetime, and maintains energy density, while simplifying the manufacturing process and reducing costs.
Implementation Method 1
A surface layer which is formed on the surface of the negative electrode material layer, is formed of insulating particles that are inert with respect to lithium, and partially shields the negative electrode material layer
Data Source
AI summary
Disclosed is a rapidly rechargeable lithium secondary battery. The present invention provides a negative electrode for a lithium secondary battery, the negative electrode being characterized by including: a current collector; a negative electrode material layer which is formed on the current collector and includes negative electrode active material particles, conductive material particles, and a binder; and a surface layer which is formed on the surface of the negative electrode material layer, is formed of insulating particles that are inert with respect to lithium, and partially shields the negative electrode material layer. According to the present invention, a negative electrode for a lithium secondary battery having a high charging speed without lifetime degradation can be provided.