Graphene-Coated Current Collector for Lithium Foil Lamination
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Solution Overview
Problem
Lithium metal batteries face challenges with lithium foil sticking during manufacturing, leading to defects and reduced productivity, along with issues of weak adhesion and increased resistance at the interface between the substrate and lithium foil, which affect the battery's performance and efficiency.
Innovation Solution
A method involving pretreating a current collector substrate foil with graphene using wet or dry methods to enhance adhesion and conductivity, followed by laminating lithium metal foils onto both sides of the graphene-treated substrate, utilizing an in-line roll-to-roll manufacturing apparatus in a vacuum configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lithium metal foil is pressed onto copper foil current collector using steel rolls, then the anode material is formed, but the lithium foil sticks to the rolls causing defects and reduced productivity
Solution Approach 1:
A release film is introduced as an intermediary layer between the lithium foil and the steel press rolls. This release film prevents direct contact and adhesion between the lithium foil and rolls, eliminating sticking issues while maintaining the pressing function. The release film acts as a mediator that allows the pressing operation to proceed without the harmful sticking effect.
2Strength
If strong pressing force is applied to laminate lithium foil onto substrate, then adhesion is improved, but lithium foil sticks to press rolls
Solution Approach 1:
The release film serves as a mediator that decouples the pressing force transmission from direct contact. It allows sufficient pressing force to be applied for good adhesion between lithium foil and substrate while preventing the lithium foil from adhering to the press rolls. The release film transmits the necessary mechanical pressure without creating harmful adhesion to the rolls.
3Ease of operation
If notching process is performed on lithium metal, then individual pieces are separated, but sticking to molds occurs during punching
Solution Approach 1:
The release film acts as a protective intermediary during the notching process. It prevents the lithium metal from directly contacting and sticking to the mold surfaces during punching and notching operations. This allows clean separation of individual pieces without mold contamination, maintaining ease of operation while eliminating the harmful sticking effect.
4Productivity
If magazine storage is used for notched lithium pieces, then pieces are stored for later use, but pressure from weight causes pieces to stick together
Solution Approach 1:
The release film serves as a separation intermediary during magazine storage. It prevents direct contact between stacked lithium pieces, eliminating the sticking caused by weight pressure. This maintains piece separation and structural stability during batch storage while preserving the productivity benefits of magazine-based batch processing.
5Quantity of substance
If thin lithium foil with thickness less than 100 μm is produced, then energy density is improved, but sticking phenomena increase during manufacturing
Solution Approach 1:
The release film acts as a protective intermediary that enables the manufacturing of thin lithium foil (less than 100 μm). By preventing direct contact between the thin, soft lithium foil and the press rolls or molds, it eliminates sticking phenomena that would otherwise be exacerbated by the reduced thickness, allowing production of high-energy-density thin foils.
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 method improves adhesion and electrical conductivity, enhancing the quality and productivity of lithium metal anode materials, thereby addressing sticking issues and improving the battery's performance.
Implementation Method 1
pretreating a current collector substrate foil with graphene to enhance the adhesion between a substrate and a lithium layer
Implementation Method 2
pretreating a current collector substrate foil with graphene to enhance binding between the substrate and the lithium foil, as well as to improve electrical conductivity
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The method for manufacturing anode materials of a lithium metal battery according to the present invention includes the steps of preparing a current collector substrate foil; pretreating the first surface of the current collector substrate foil by coating graphene thereon using a wet or dry method; pretreating the second surface, which is the opposite side of the current collector substrate foil, by coating graphene thereon using a wet or dry method; forming an anode material by laminating a lithium metal foil onto both sides of the graphene-pretreated substrate using a press roll; and winding the laminated anode material.