Lithium Electrode Conductive Fiber Frame for Press Integrity
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Solution Overview
Problem
The roll press process in lithium battery electrode fabrication leads to breakage of active materials, reducing electronic conductivity and resulting in poor long lifespan and high-rate charge and discharge characteristics.
Innovation Solution
A fabricating method involving the formation of a conductive fiber structure layer in a frame form on the active material layer before pressing, using a slurry with fibrous conductive materials like carbon nanotubes or carbon nanofibers, to prevent breakage and maintain electronic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a roll press process is applied to increase electronic conductivity among active materials, then electronic conductivity is improved, but active material particles are broken and electrode deterioration occurs
Solution Approach 1:
A conductive fiber structure layer is formed on the surface of the active material layer before the roll press process. This preliminary action creates a protective framework that prevents active material particles from breaking during subsequent pressing, while still allowing the press process to improve electronic conductivity among particles.
Solution Approach 2:
The conductive fiber structure layer acts as a cushioning layer that absorbs and distributes the pressure applied during the roll press process. This beforehand cushioning prevents direct transmission of crushing forces to the active material particles, thereby preventing particle breakage while maintaining the effectiveness of the press process for improving conductivity.
2Quantity of substance
If active material particles are broken by roll press, then pressure is delivered to inner side for densification, but particle destruction reduces electronic conductivity and causes lithium deposition
Solution Approach 1:
The conductive fiber structure layer is formed before pressing to create a protective network that allows densification to proceed without particle breakage. This preliminary protective action ensures that particles remain intact while still achieving the desired density increase through the press process.
Solution Approach 2:
The conductive fiber structure layer serves as an intermediary between the pressing mechanism and the active material particles. It mediates the pressure transmission, allowing sufficient force for densification while preventing direct contact and breakage of particles, thereby maintaining electronic conductivity.
3Reliability
If roll press is applied to maintain electronic conductivity among inner active materials, then conductivity is improved, but surface active materials are damaged
Solution Approach 1:
The conductive fiber structure layer is formed on the surface before the roll press process as a preliminary protective measure. This layer shields surface active materials from direct mechanical damage during pressing, while still allowing the press process to effectively improve conductivity among inner active materials.
Solution Approach 2:
The conductive fiber structure layer provides localized protection specifically to the surface region where active materials are most vulnerable to damage. This local quality approach allows the surface to be protected while the inner regions still receive the beneficial densification and conductivity improvement from the press process.
Data Source
AI summary
The present invention provides a fabricating method of a lithium electrode, a lithium electrode, and a lithium secondary battery including the same, the fabricating method including: a) forming an active material layer on one surface or active material layers on both surfaces of a current collector; b) forming a conductive fiber structure layer in a frame form on a surface of the active material layer; and c) pressing the current collector on which the conductive fiber structure layer in a frame form is formed. Since breakage of the active materials caused by pressing is prevented by the conductive fiber structure layer in a frame form, the present invention provides a lithium electrode capable of maintaining electronic conductivity between active material particles and having a long lifespan and high-rate charge and discharge characteristics.