Core-Shell Electrode Material for High-Rate Battery Resistance
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Solution Overview
Problem
Non-aqueous electrolyte secondary batteries face an increase in internal resistance, particularly in high-rate applications like in-vehicle batteries, due to insulating thin films from binders hindering electron and ion conduction networks.
Innovation Solution
A core-shell electrode material is developed where a conductive material coats the electrode active material, and a gel-forming polymer with high tensile elongation forms a flexible shell, ensuring stable electron and ion conduction paths despite expansion and shrinkage during charge and discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a binder is used to bind electrode active materials and current collector, then electrode structural stability is improved, but internal resistance increases due to insulating thin films
Solution Approach 1:
The patent introduces a conductive coating layer as an intermediary substance between the binder and the electrode active material. This conductive layer mediates the interaction by providing a conductive pathway that bypasses the insulating binder, thus reducing internal resistance while maintaining the structural binding function. The conductive coating acts as a mediator that connects the active material to the conductive network without direct contact with the insulating binder.
Solution Approach 2:
The patent applies a thin conductive film or coating on the surface of the electrode active material particles. This thin conductive film forms a flexible shell that maintains structural integrity while providing continuous electrical conductivity. The thin film structure allows the electrode to maintain stability during volume changes while minimizing resistance increase from binder materials.
2Reliability
If conventional binders are used to secure electrode structure, then electrode integrity is improved, but electron and ion conduction networks are hindered
Solution Approach 1:
The patent applies different functional properties to different regions of the electrode structure. The bulk binder material provides structural integrity in the matrix, while the conductive coating on the particle surfaces provides localized conductivity pathways. This local differentiation allows the electrode to maintain integrity overall while having specific conductive regions that enable fast electron and ion transport.
Solution Approach 2:
The patent creates a composite electrode structure combining binder materials with conductive coating materials on electrode active material particles. This composite structure integrates the structural binding function of the binder with the conductive function of the coating, achieving both electrode integrity and enhanced conductivity for improved charge-discharge rates.
3Power
If high current charge and discharge is performed, then power density is improved, but internal resistance increases significantly
Solution Approach 1:
The patent applies conductive coatings to electrode active material particles in advance, before electrode assembly and battery operation. This preliminary conductive treatment ensures that conductivity pathways are pre-established, allowing the electrode to immediately handle high current loads without developing resistance issues during operation. The conductive network is prepared beforehand to accommodate high power demands.
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
This configuration effectively minimizes internal resistance, enhancing the power density and rate characteristics of non-aqueous electrolyte secondary batteries by maintaining a stable conduction network and preventing shell breakage.
Implementation Method 1
a gel-forming polymer having a tensile elongation at break of 10% or more in a gel state
Implementation Method 2
a core part in which at least a part of a surface of an electrode active material is coated with a first conductive material
Implementation Method 3
Charging and discharging reactions of a battery occur by absorption and desorption of ions such as lithium ions on electrode active materials
Data Source
AI summary
A core-shell-type electrode material is used as an electrode active material layer of a non-aqueous electrolyte secondary battery, the core-shell-type electrode material having a core part in which at least a part of a surface of an electrode active material is coated with a first conductive material and a shell part in which a second conductive material is contained in a base material formed by a gel-forming polymer having a tensile elongation at break of 10% or more in a gel state.