Lithium Metal Foil Laser Cutting With Sublimation-Dominant Edges
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Solution Overview
Problem
Existing methods for cutting lithium metal foils, particularly for battery applications, face challenges such as the formation of bead structures and spatters due to local melting, which can lead to critical current peaks, dendrite formation, and increased risk of short circuits, compromising the electrical performance and long-term stability of batteries.
Innovation Solution
A method and device utilizing pulsed laser radiation with controlled pulse intervals and parameters to minimize metal melting, primarily sublimating the metal instead of melting it, thereby reducing the formation of bead structures and spatters, ensuring a cleaner cutting edge suitable for battery components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a continuous wave laser is used to cut lithium foil, then the cutting process is efficient and fast, but bead structures and metal splashes form due to local melting
Solution Approach 1:
The patent applies periodic pulsed laser radiation instead of continuous wave laser. The laser emits pulses with specific duty cycles (1% to 50%, preferably 10% to 30%) and frequencies (1 Hz to 100 kHz, preferably 1 kHz to 10 kHz), creating periodic heating and cooling cycles that prevent continuous melting while maintaining efficient material removal through sublimation.
Solution Approach 2:
The patent changes the temporal parameters of laser radiation from continuous to pulsed mode. By adjusting pulse duration, frequency, and duty cycle, the energy delivery is optimized to achieve sublimation-dominated material removal rather than melting, thereby eliminating bead and splash formation while preserving cutting efficiency.
2Productivity
If punching is used to cut lithium foil, then the process is simple and fast, but the foil sticks to the punching tool causing downtime and high scrap rates
Solution Approach 1:
The patent replaces the mechanical punching system with a non-contact laser-based cutting system. This substitution eliminates direct physical contact between the cutting tool and the lithium foil, preventing adhesion and sticking issues that cause downtime and scrap in mechanical punching processes.
Solution Approach 2:
The laser beam acts as an intermediary between the power source and the lithium foil, transferring energy without physical contact. This intermediary approach allows cutting to occur through energy deposition and material sublimation rather than mechanical force, avoiding the sticking problem inherent in direct mechanical contact methods.
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 approach effectively reduces the risk of critical side reactions, dendrite formation, and electrical short circuits, enhancing the long-term stability and safety of batteries by preventing the formation of defects at the cutting edge.
Implementation Method 1
pulsed laser radiation, which the laser radiates in the direction of a foil positioned by the means for positioning a foil, cuts through the at least one layer of metal of the foil in such a way that the metal of the foil mainly sublimates and hardly melts
Implementation Method 2
a laser for cutting the foil and/or a means for positioning a foil are controlled such that pulsed laser radiation, which the laser radiates in the direction of a foil positioned by the means for positioning a foil
Data Source
AI summary
The invention relates to a device for cutting a foil which contains or consists of at least one layer of metal (in particular lithium). The method and the device are characterized in that a laser for cutting the foil and/or a means for positioning the foil is controlled such that pulsed laser radiation, which the laser emits in the direction of a foil positioned by the means for positioning a foil, cuts through at least one layer of metal of the foil in such a manner that the metal of the foil is mostly sublimated and scarcely melts. By virtue of the method and the device, it is possible to provide a laser-cut foil which does not have bead structures and/or metal splashes of solidified metal in the cut region or only has very small bead structures and/or metal splashes of solidified metal in the cut region. When the foil is used as part of the battery, the electric performance and durability of the battery is greater and the risk of a short circuit in the battery cell is lower.