Roll Anode Alkaliation to Prevent Edge Lithium Plating
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Solution Overview
Problem
Lithium ion batteries face issues with irreversible capacity loss due to lithium metal plating and dendrite buildup on bare substrate areas during electrochemical lithiation, especially in anode rolls coated on both sides, which complicates mass production and cell assembly processes.
Innovation Solution
The use of electrochemical processes involving forward/reverse current methods, rest period methods, and edge guard techniques to prevent lithium or alkali metal plating and dendrite formation on bare substrate areas, utilizing non-aqueous electrolyte solutions and specific coatings like graphite or silicon, and employing dielectric edge guards to manage lithium deposition and intercalation effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrochemical lithiation is performed on anode rolls with bare substrate areas, then lithium ion batteries can be produced efficiently, but lithium metal plating and dendrite buildup occur on bare substrate areas causing safety issues and capacity loss
Solution Approach 1:
The patent removes the harmful bare substrate areas from the anode structure by providing full coating coverage, thereby extracting the source of lithium plating and dendrite formation while maintaining production efficiency
Solution Approach 2:
The patent applies different coating materials or compositions to different regions of the anode substrate to optimize local properties, preventing lithium plating in specific areas while maintaining overall battery performance
2Reliability
If anode rolls are coated on both sides to eliminate bare substrate areas, then lithium plating is prevented, but it complicates cell assembly processes such as tab welding and slitting
Solution Approach 1:
The patent applies coating selectively to specific regions of the anode substrate rather than uniform full coverage, preventing lithium plating in critical areas while leaving other areas accessible for cell assembly operations
Solution Approach 2:
The patent divides the anode coating into functional zones with different properties, separating the lithium-plating prevention function from the cell assembly accessibility requirement
3Quantity of substance
If higher capacity anode materials like amorphous silicon are used, then specific capacity increases significantly, but irreversible capacity loss increases to 25%
Solution Approach 1:
The patent combines amorphous silicon with other materials to create a composite anode structure that maintains the high capacity benefits of silicon while reducing irreversible capacity loss through synergistic effects
Solution Approach 2:
The patent modifies the physical or chemical parameters of the anode material, such as particle size, morphology, or composition ratios, to optimize the balance between capacity and cyclability
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
These methods enable the production of alkaliated anodes with controlled lithium distribution, reducing irreversible capacity loss and ensuring safe, practical cell assembly by maintaining lithium-free areas, thus enhancing the efficiency and safety of lithium ion battery production.
Implementation Method 1
adding lithium to the anode active material by electrolysis in a non-aqueous and dry environment
Implementation Method 2
electrochemical processes involving forward/reverse current methods, rest period methods, and edge guard techniques to prevent lithium or alkali metal plating
Implementation Method 3
Graphite offers a reversible capacity of about 370 mAh/gram
Implementation Method 4
employing dielectric edge guards to manage lithium deposition and intercalation effectively
Data Source
AI summary
The present invention relates to processes that may be used singly or in combination to prevent lithium (or alkali metal) plating or dendrite buildup on bare substrate areas or edges of electrode rolls during alkaliation of a battery or electrochemical cell anode composed of a conductive substrate and coatings, in which the electrode rolls may be coated on one or both sides and may have exposed substrate on edges, or on continuous or discontinuous portions of either or both substrate surfaces.