Alkaliating Roll Anodes Preventing 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 double-sided anode rolls, which are not effectively addressed by existing methods.
Innovation Solution
The use of a forward/reverse current method, rest period method, and edge guard method to prevent lithium or alkali metal plating and dendrite buildup on bare substrate areas, involving a conductive substrate coated with active materials like graphite or silicon, and applying forward/reducing currents with periodic reversal or using dielectric edge guards to manage lithium deposition and intercalation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electrochemical lithiation is applied to anode rolls with bare substrate areas, then lithium intercalation into active material occurs, but lithium metal plating and dendrite buildup occur on bare substrate areas
Solution Approach 1:
The patent applies preliminary action by conducting electrochemical lithiation before cell assembly to pre-intercalate lithium into the active material and form SEI layers, thereby compensating for irreversible capacity loss and preventing subsequent lithium plating on bare substrate areas during battery operation
Solution Approach 2:
The patent applies local quality by selectively controlling lithium deposition in different areas of the anode roll - promoting lithium intercalation in coated active material areas while preventing lithium plating on bare substrate areas through controlled electrochemical processing, thus creating spatially differentiated lithium distribution
2Productivity
If double-sided anode rolls are used to increase production efficiency, then productivity improves, but lithium plating occurs on both coated and bare substrate areas including edges
Solution Approach 1:
The patent applies local quality by implementing spatially selective protection - using dielectric edge guards specifically at edges and bare substrate areas while allowing lithium intercalation in coated areas, thus enabling double-sided processing without uniform lithium deposition throughout the entire anode roll
Solution Approach 2:
The patent introduces dielectric edge guards as intermediary elements that physically block and electrically insulate edges and bare substrate areas from direct lithium deposition, serving as a mediator between the electrolyte and vulnerable anode regions to prevent plating while allowing productive lithiation elsewhere
3Reliability
If reference electrodes are used to detect bare copper areas and turn off current, then lithium plating on detected areas is prevented, but the method is impractical for double-sided anode rolls and does not protect edges
Solution Approach 1:
The patent applies segmentation by dividing the anode roll into distinct functional zones - coated areas that receive lithium intercalation and bare substrate areas/edges that receive protection through dielectric guards, allowing independent control of lithium deposition in different spatial segments without requiring complex detection systems
Solution Approach 2:
The patent replaces complex reference electrode detection systems with simpler dielectric edge guards that passively prevent lithium plating through physical and electrical isolation, serving as an intermediary barrier that eliminates the need for active detection and control systems while providing universal protection
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 effectively prevent lithium metal deposition on bare substrate areas, allowing for controlled lithium compensation and safe cell assembly by ensuring clean, lithium-free surfaces for welding and other processes, thereby enhancing the efficiency and practicality of anode production.
Implementation Method 1
applying forward/reducing currents with periodic reversal
Implementation Method 2
forward/reverse current method
Implementation Method 3
edge guard method... using dielectric edge guards to manage lithium deposition
Implementation Method 4
conductive substrate coated with active materials like graphite or silicon... controlled lithium compensation
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.