Web Edge Metrology for Closed-Loop Lithium Anode Deposition
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Solution Overview
Problem
Current roll-to-roll deposition systems face challenges in accurately monitoring and controlling material deposition on flexible substrates, leading to issues with internal resistance, surface roughness, and consistency in energy storage devices like lithium-ion batteries, due to uncontrolled web material alignment and positioning.
Innovation Solution
A flexible substrate coating system with a processing module and metrology module, featuring non-contact sensors such as spectrographic, eddy current, and optical profilometers, which guide the substrate through a series of deposition units while monitoring thickness, surface roughness, and web flutter, ensuring precise lithium metal film deposition and protection layer application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional contact-based sensors are used for monitoring deposition, then measurement capability is provided, but web flutter and surface roughness cause measurement errors and reduced precision
Solution Approach 1:
The patent replaces contact-based mechanical sensors with non-contact optical sensors (laser triangulation sensors, spectrographic sensors) to measure deposition thickness and web position. This eliminates mechanical contact that causes web flutter and measurement errors, allowing accurate measurement without physical interference with the moving flexible substrate
Solution Approach 2:
The patent introduces optical fields (laser beams, spectrographic light) as intermediaries to transmit measurement information from the substrate to sensors without direct contact. The optical intermediary allows measurement through air gap, avoiding mechanical contact issues while maintaining measurement capability
2Productivity
If web material is not precisely aligned with deposition source, then processing speed is maintained, but deposition uniformity and manufacturing precision deteriorate
Solution Approach 1:
The patent implements real-time feedback control using non-contact sensors to continuously monitor web position and deposition thickness. The sensor data feeds back to control systems that adjust deposition source positioning or web tension dynamically, maintaining precise alignment and uniform deposition without reducing processing speed
Solution Approach 2:
The patent employs dynamic adjustment mechanisms that respond in real-time to web position variations. The system transitions from static alignment to dynamic control, where deposition parameters and web positioning are continuously adjusted during operation to maintain precision at high speeds
3Reliability
If multiple sensors are positioned along transverse direction, then comprehensive monitoring is achieved, but device complexity increases
Solution Approach 1:
The patent designs multi-functional sensor units that perform multiple measurement tasks simultaneously. For example, a single sensor array can measure both web position and deposition thickness using different optical wavelengths or measurement modes, reducing the total number of separate sensor systems needed while maintaining comprehensive monitoring capability
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 system achieves high-quality, consistent lithium metal film deposition and protection layer application, reducing internal resistance and improving the performance and yield of energy storage devices by providing real-time feedback for process adjustments.
Implementation Method 1
The plurality of non-contact sensors include a spectrographic sensor assembly operable to capture spectrographic images of coated and uncoated portions of the continuous sheet of flexible material
Implementation Method 2
The plurality of non-contact sensors includes a first eddy current sensor operable to measure a thickness of a coated portion of the continuous sheet of flexible material
Implementation Method 3
The coating system further includes an optical profilometer operable to measure web flutter of the continuous sheet of flexible material
Implementation Method 4
The plurality of non-contact sensors include a web roughness sensor operable to measure surface roughness of a coated portion of the continuous sheet of flexible material and an uncoated portion of the continuous sheet of flexible material. The web roughness sensor includes an argon laser and a CMOS camera
Implementation Method 5
guiding the continuous sheet of flexible material past a plurality of deposition units while depositing a lithium metal film on the flexible substrate via the plurality of deposition units
Data Source
AI summary
Metrology systems and processing methods for continuous lithium ion battery (LIB) anode pre-lithiation and solid metal anode protection are provided. In some embodiments, the metrology system integrates at least one complementary non-contact sensor to measure at least one of surface composition, coating thickness, and nanoscale roughness. The metrology system and processing methods can be used to address anode edge quality. The metrology system and methods can facilitate high quality and high yield closed loop anode pre-lithiation and anode protection layer deposition, alloy-type anode pre-lithiation stage control improves LIB coulombic efficiency, and anode coating with pinhole free and electrochemically active protection layers resist dendrite formation.