Facile slitting or cutting of flexible substrate containing reactive metal or alloy film

Abstract

Systems and methods for cutting substrates including metals, for example, lithium metals, which can be used in energy storage devices. In one aspect, a system for slitting a flexible support layer stack is provided. The system includes a laser source configured to generate a laser beam, the laser beam directed toward a first surface of a flexible support layer stack. The system further includes an optical scanner configured to direct the laser beam toward the first surface of the flexible support layer stack. The system further includes a pickup roller positioned opposite the laser beam, the pickup roller positioned to contact a second surface of the flexible support layer stack, the second surface opposite the first surface. The system further includes a cutting assembly positioned downstream of the laser beam.

Description

FACILE SLITTING OR CUTTING OF FLEXIBLE SUBSTRATE CONTAINING REACTIVE METAL OR ALLOY FILMBACKGROUNDField

[0001] The present disclosure generally relates to systems and methods for cutting substrates including metals, for example, lithium metals, which can be used in energy storage devices.Description of the Related Art

[0002] Rechargeable electrochemical storage systems are increasing in importance for many fields of everyday life. High-capacity energy storage devices, such as lithium-ion (Li-ion) batteries and capacitors, are used in a growing number of applications, including portable electronics, medical, transportation, grid-connected large energy storage, renewable energy storage, and uninterruptible power supply (UPS). In each of these applications, the charge / discharge time and capacity of energy storage devices are fundamental parameters. In addition, the size, weight, and / or cost of such energy storage devices are also fundamental parameters. Further, low internal resistance is integral for high performance. The lower the resistance, the less restriction the energy storage device encounters in delivering electrical energy. For example, in the case of a battery, internal resistance affects performance by reducing the total amount of useful energy stored by the battery as well as the ability of the battery to deliver high current.

[0003] One method for manufacturing energy storage devices is roll-to-roll processing. An effective roll-to-roll deposition process not only provides a high deposition rate, but also provides a film surface, which lacks small-scale roughness, contains minimal defects, and is flat, for example, lacks large scale topography. In addition, an effective roll-to-roll deposition process also provides consistent deposition results or “repeatability.”

[0004] Thin film lithium energy storage devices typically employ a lithium deposition process where a thin film of lithium is deposited on or over a substrate or web before being laminated with an anode. Roll-to-roll processing often involves a certain roll width to be economical, even if the targeted roll width is smaller. The rolls coated with lithium may be cut to achieve the targeted roll width.

[0005] Therefore, there is a need for improved apparatus and methods for cutting of substrate including lithium thin films for energy storage devices.SUMMARY

[0006] The present disclosure generally relates to systems and methods for cutting substrates including metals, for example, lithium metals, which can be used in energy storage devices.

[0007] In one aspect, a system for slitting a flexible support layer stack is provided. The system includes a laser source configured to generate a laser beam, the laser beam directed toward a first surface of a flexible support layer stack. The system further includes an optical scanner configured to direct the laser beam toward the first surface of the flexible support layer stack. The system further includes a pickup roller positioned opposite the laser beam, the pickup roller positioned to contact a second surface of the flexible support layer stack, the second surface opposite the first surface. The system further includes a cutting assembly positioned downstream of the laser beam.

[0008] Implementations may include one or more of the following. The laser source is an infrared laser source. The flexible support layer stack has an alkali metal film formed on the first surface. The flexible support layer stack includes a polymer material selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), poly(methyl methacrylate) (PMMA), cellulose tri-acetate (TAC), polypropylene (PP), polyethylene (PE), polycarbonates (PC), multilayers thereof, or a combination thereof. The cutting assembly includes a rotary blade. The cutting assembly further includes a blade stage. The cutting assembly includes a second optical scanner configured to direct a second laser beam toward the flexible support layer stack. The system further includes a supply roller for supplying the flexible support layer stack and a take-up roller for collecting the cut flexible support layer stack. The pickup roller includes stainless steel.

[0009] In another aspect, a slitting apparatus is provided. The slitting apparatus includes a laser unit. The laser unit includes an optical assembly, a laser source coupled to the optical assembly, and a controller coupled to the optical assembly. The slitting apparatus further includes a blade assembly positioned downstream of thelaser unit and a pickup roller positioned upstream from the blade assembly and opposite the optical assembly.

[0010] Implementations may include one or more of the following. The laser source is a solid-state laser configured to produce a continuous laser beam. The laser source is a solid-state laser configured to produce a pulsed laser beam. The blade assembly includes a rotary blade. The pickup roller includes stainless steel.

[0011] In yet another aspect, a method of slitting a coated substrate is provided. The method includes feeding a coated substrate including at least one coating layer and a substrate layer to a laser unit, exposing a blade cutting area on the coated substrate by activating a section of the at least one coating layer from the substrate layer of the coated substrate, removing the activated section of the at least one coating layer, subsequently feeding the coated substrate to a blade assembly, and slitting the coated substrate using the blade assembly within the blade cutting area.

[0012] Implementations may include one or more of the following. The laser unit includes an optical assembly, a laser source coupled to the optical assembly, an optical bench positioned opposite the optical assembly, and a controller coupled to the optical assembly. The coating layer includes lithium. The substrate layer includes a flexible substrate further comprising polyethylene terephthalate, polyimide, polyphenylene sulfide, alloys thereof, or combinations thereof. The substrate layer includes a flexible conductive substrate further comprising copper, nickel, aluminum, zinc, cobalt, tin, silicon, manganese, magnesium, alloys thereof, or combinations thereof. The blade cutting area is at least one longitudinal section of the coated substrate configured to produce at least two slit coated substrates.

[0013] In another aspect, a non-transitory computer readable medium has stored thereon instructions, which, when executed by a processor, causes the process to perform operations of the above apparatus and / or method.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description of the aspects, briefly summarized above, may be had by reference to implementations, some of which are illustrated in the appended drawings. It is to be noted, however, that theappended drawings illustrate only typical implementations of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective implementations.

[0015] FIG. 1A illustrates a schematic diagram of an exemplary system for cutting or slitting metals in accordance with one or more implementations of the present disclosure.

[0016] FIG. 1 B illustrates a schematic diagram of another exemplary system for cutting or slitting metals in accordance with one or more implementations of the present disclosure.

[0017] FIG. 2 illustrates a top plan view of a flexible support layer stack in accordance with one or more implementations of the present disclosure.

[0018] FIG. 3A illustrates a cross-sectional side view of the flexible support layer stack taken along line 3A-3A of FIG. 2 in accordance with one or more implementations of the present disclosure.

[0019] FIG. 3B illustrates a cross-sectional side view of the flexible support layer stack taken along line 3B-3B of FIG. 2 in accordance with one or more implementations of the present disclosure.

[0020] FIG. 3C illustrates a cross-sectional side view of the flexible support layer stack taken along line 3C-3C of FIG. 2 in accordance with one or more implementations of the present disclosure.

[0021] FIG. 3D illustrates a cross-sectional view of the flexible support layer stack taken along line 3D-3D of FIG. 2 in accordance with one or more implementations of the present disclosure.

[0022] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one implementation may be beneficially incorporated in other implementations without further recitation.DETAILED DESCRIPTION

[0023] The present disclosure generally relates to systems and methods for cutting substrates including metals, for example, lithium metals, which can be used in energy storage devices.

[0024] Soft metals, such as lithium metal can function as electrode materials in electrochemical cells and batteries. Bulk lithium can be purchased commercially as a solid suspension in oil or as a foil. It can also be deposited on to a substrate using a variety of techniques, such as vapor deposition, vacuum deposition, or molecular beam epitaxy techniques. In order to fit the dimensions for a particular electrochemical application, the bulk lithium may involve cutting.

[0025] However, cutting metals, such as lithium metal, can present several challenges. For example, lithium metal is soft and malleable such that when it is cut, it may be sticky and adhere to the cutting instrument (e.g., a knife, a blade, a die). This can present difficulties when cutting multiple pieces of lithium metal in succession with a cutting instrument because cleaning the cutting instrument in between each cut can slow down the process of preparing electrodes and can also dull the cutting instrument. Cutting lithium metal can also produce excess waste because each cut can accumulate lithium metal on the cutting instrument that, therefore, cannot be used in battery fabrication. Certain existing lithium metal cutting systems attempt to circumvent this issue by positioning the lithium metal between interleafs so that the lithium metal does not directly contact the cutting instrument. However, even in such existing systems, the lithium can still undesirably adhere to the interleaf materials, making subsequent removal of the lithium from the interleaf materials difficult. Other existing lithium metal cutting systems utilize ultrasonic cutting techniques. However, for high volume manufacturing, periodic maintenance is often used to eliminate particle debris build-up on the blade and long slitting of the web without changing the blade becomes challenging.

[0026] In one or more implementations, which can be combined with other implementations, systems and methods for slitting and cutting substrates by first removing reactive metal or alloy film from the substrate to be cut by a laser lift-off process. The laser lift-off process creates cutting lanes that are free from the reactive metal or alloy film. The blades can then cut the substrate along the cutting lanes,which eliminates or reduces the accumulation of the reactive metal or alloy film on the blade. This elimination or reduction of the accumulation of reactive metal or alloy film on the blade increases cutting blade lifetime, which increases the time between maintenance cycles. Cutting the substrate directly rather than the reactive metal or alloy directly provides for a cleaner cut of the substrate when compared to cutting the reactive metal or alloy directly with a blade. A cleaner cut reduces the amount of reactive metal or alloy film that may adhere to the blade after cutting. Additionally, a cleaner cut, as provided by the system and methods described, may allow for multiple, repeated cuts in succession while reducing the amount of metal waste produced when compared to a currently available systems blade that cut the metal directly. Furthermore, the edges of the metal can be smoother and less jagged than metals cut with existing systems, which can reduce tearing and / or damaging other components (e.g., a polymeric layer, a battery separator) of an electrochemical cell.

[0027] In one or more implementations, which can be combined with other implementations, systems and methods for patterned lithium removal from a flexible support layer utilizing a laser are provided. The patterned removal of lithium creates cutting lanes on the flexible support layer that are free or substantially free from lithium allowing the cutting blade to cut the flexible support layer along the cutting lanes without lithium build-up on the cutting blade. In one or more implementations, an IR fiber laser is used to activate the flexible support layer-Li interface, for example, the PET-Li interface, from the flexible support layer side. Lithium at the activated flexible support layer-Li interface may be subsequently removed using a pickup roller and / or a sacrificial film, for example, a plastic film, to expose the underlying flexible support layer creating the cutting lanes for the blade.

[0028] In one or more implementations, which can be combined with other implementations, the laser lift-off process or laser activation process described can be incorporated into a roll-to-roll tool and used in a roll-to-roll process. The laser activation process enables transfer of patterned lithium from a plastic substrate onto a pickup roller or sacrificial film, for example, a plastic film, by exposing an interface between the lithium metal layer and the flexible support layer, for example, the Li-PET interface, to a laser which induces lithium transfer at the interface. This interface between the lithium metal layer and the flexible support layer may also include a release layer as described.

[0029] In one or more implementations, which can be combined with other implementations, the laser activation process enables the patterning of the flexible support layer stack (e.g., the flexible support layer and lithium metal layer). For example, the lithium can be patterned to match the pattern of the anode material in a pre-lithiation process, such as lane coating, skip coating, and also directly onto a current collector. Any suitable pattern may be achieved, for example, a square, a triangle, a circle, etc.

[0030] In one or more implementations, which can be combined with other implementations, the laser activation process can use a laser source to create an interface reaction with either a release layer, an interface layer, or both the release layer and the interface layer between the lithium metal layer and the flexible support layer, for example, PET, to enable subsequent removal of the lithium metal layer at the activated interface.

[0031] In one or more implementations, which can be combined with other implementations, an IR fiber laser is used for laser activation and lift-off from a PET substrate with a lithium layer, for example, a 20 urn lithium layer, and a silicone release layer. In one example, the IR fiber laser is a 1064-nm laser with a pulse width of 5 to 500 nanoseconds, for example, a 30 nanosecond pulse width, a Gaussian profile, ~150 urn spot size, 2 m / sec scan speed, and a line distance of 70 urn generating a wobble pattern or hatch pattern. The wobble pattern can be used for narrow width lane cleaning and the hatch pattern can be used for wide width lane cleaning.

[0032] In one or more implementations, which can be combined with other implementations, a flexible support layer stack is provided. The flexible support layer stack can include a plastic containing substrate, for example, a polyethylene terephthalate (PET) substrate. The flexible support layer stack can further include a release layer, for example, silicone or other deposited release layers, formed on the flexible support layer stack. An alkali metal-containing layer, for example, a lithium metal layer is formed over the flexible support layer stack. In implementations where the release layer is not present, the lithium metal layer can be formed directly on the plastic containing substrate. In implementations where the release layer is present, the lithium metal layer can be formed directly on the release layer. The flexible support layer having the lithium metal layer formed thereon is exposed to a laser activationprocess. In one or more implementations, during the laser activation process, a laser is directed through the flexible support layer to activate the interface of the lithium metal layer and the flexible support layer, for example, at the Li-PET interface. The laser can be directed through the backside of the flexible support layer stack, for example, from the plastic containing substrate or PET side. Exposure to the laser can induce a lithium removal process creating a void volume between the lithium metal layer and the flexible support layer. This void volume can make subsequent separation of the lithium metal layer from the flexible support layer easier during removal of the lithium metal layer from the flexible support layer stack by the pickup roller to create the cutting lanes. In addition, precise laser beam position control enables the selective removal of lithium metal to form various shapes of the lithium metal layer on the flexible support layer. Further, exposure to the laser can be used to pattern the lithium metal layer such that a precise pattern of lithium metal is removed from the flexible support layer stack.

[0033] As described, the cutting systems can be used to cut or slit substrates including a metal. Accordingly, systems and methods described herein can include a metal (e.g., a metal foil, a metal alloy). In some implementations, the metal is a soft metal. Some non-limiting examples of soft metals include lithium metal and other alkali metals, such as sodium (Na), potassium (K), cesium (Cs), and rubidium (Rb). The lithium metal can be a lithium metal alloy and / or can comprise vacuum deposited lithium metal. In some implementations, the soft metal may be or may include indium. In some implementations, systems and methods described may be suitable for cutting metals harder than the alkali metals, such as metal foils of aluminum. Other metals are possible. In some implementations, the metal foil has a thickness of less than or equal to 50 microns.

[0034] It is noted that while the particular substrate on which some implementations described herein can be practiced is not limited, it is particularly beneficial to practice the implementations on flexible substrates, including for example, web-based substrates, panels and discrete sheets. The flexible substrate can also be in the form of a foil, a polymer film, or a thin plate.

[0035] It is also noted here that a flexible substrate or web as used within the implementations described herein can typically be characterized in that it is bendable.The term “web” can be synonymously used to the term “strip,” the term “flexible substrate,” or the term “flexible conductive substrate.” For example, the web as described in implementations herein can be a polymer material.

[0036] It is further noted that the methods and systems described may be used in forming single-sided electrode structures and double-sided electrode structures.

[0037] FIG. 1 A illustrates a schematic diagram of an exemplary cutting system 100 that can be utilized to form targeted cuts in a flexible support layer stack 140, such as a thin film lithium energy storage device. The cutting system 100 is configured to accurately remove lithium films and cut underlying substrates to produce slit rolls 122 from larger source rolls 120. The cutting system 100 generally includes at least one of a laser source 102, an optical source assembly 106, a pickup roller 108, a cutting assembly, for example, a blade 118, and a controller 110 for controlling the operation of the cutting system 100. Although FIG. 1 A depicts one optical source assembly 106 producing a single laser beam 130 and a single blade 118, the cutting system 100 may include one or more optical assemblies 106 producing multiple laser beams 130 and a corresponding number of blades 118 for cutting the flexible support layer stack 140 into multiple strips.

[0038] The cutting system 100 includes a supply roller 101 or unwinder for supplying the source roll 120 of the flexible support layer stack 140 and a take-up roller 104 or winder for collecting the slit rolls 122 of the flexible support layer stack 140. The flexible support layer stack 140 moves in a travel direction shown by arrow 103 from the supply roller 101 to the take-up roller 104. The cutting system 100 may include other rollers or intermediate rollers, which are not shown for the sake of brevity.

[0039] The flexible support layer stack 140 has a frontside or front surface 140f and a backside or back surface 140b opposite the front surface 140f. Referring to FIGS. 3A-3D, the flexible support layer stack includes a flexible support layer 212. The flexible support layer 212 has a frontside 212f (also referred to as a front surface) and a backside 212r (also referred to as a back surface) opposite the frontside 212f. The flexible support layer 212 may include any suitable material that is compatible with the targeted processing conditions. In some implementations, the flexible support layer 212 includes a plurality of sub-layers. In one or more implementations, whichcan be combined with other implementations, the flexible support layer 212 can be or include, one or more layers selected from plastic, polymer materials, metallized plastic, metals, paper, multilayers thereof, or a combination thereof. Suitable polymer materials include polymer materials that are transparent to laser light and have low to no photon absorption to prevent overheating and fire incidents. Examples of suitable polymer materials include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), poly(methyl methacrylate) (PMMA), cellulose tri-acetate (TAC), polypropylene (PP), polyethylene (PE), polycarbonates (PC), multilayers thereof, or a combination thereof. In one or more implementations, which can be combined with other implementations, the flexible support layer 212 is a web-based substrate as is shown in FIG. 1A.

[0040] The flexible support layer stack 140 may further include a release layer (not shown). The release layer may be formed on the frontside 212f of the flexible support layer 212. The release layer may be or include any material suitable for releasing the subsequently formed materials from the flexible support layer 212 during, for example, a substrate independent direct transfer (SIDT) process.

[0041] The flexible support layer stack 140 further includes an alkali metal film, for example a lithium film 214. Referring to FIG. 3A, an alkali metal film, for example a lithium film 214 is formed over the frontside 212f of the flexible support layer 212 or the release layer (if present). The lithium film 214 includes a frontside 214f (also referred to as a front surface) and a backside 214r (also referred to as a back surface) opposite the frontside 214f. In one or more implementations, where the release layer is present, the lithium film 214 may be formed directly on the release layer. In one or more implementations, as shown in FIG. 3A, the lithium film 214 is formed directly on the frontside 212f of the flexible support layer 212. The lithium film 214 may be or include lithium. The lithium film 214 may be deposited under vacuum. The lithium film 214 may be deposited under vacuum in a roll-to-roll deposition system, for example, via a physical vapor deposition process, for example, an evaporation process or a sputtering process. The evaporation process may be an electron beam evaporation process or a thermal evaporation process.

[0042] The cutting system 100 further includes at least one of the laser source 102 and an optical source assembly 106. The laser source 102 is configured to generatea laser beam 130 and the optical source assembly 106 is configured to direct the laser beam 130 toward the back surface 140b of the flexible support layer stack 140, for example, the backside 212r of the flexible support layer 212.

[0043] Generally, the laser source 102 may be a solid-state laser, such as a diode- pumped solid-state laser having a fiber, a rod, or slab gain medium, configured to generate the laser beam 130 to irradiate the flexible support layer stack 140 for forming one or more cuts therein. The laser beam 130 may be a continuous or pulsed laser beam. The laser fiber, rod, or slab may be formed of any suitable laser crystal materials, including neodymium-doped yttrium aluminum garnet (Nd:YAG; Nd:Y3AI5O12), ytterbium-doped YAG (Yb:YAG), neodymium-doped yttrium orthovanadate (Nd:YVO; Nd:YVO4), and alexandrite. In particular implementations, the laser rod or slab has a face pumping geometry. In particular implementations, the laser slab has an edge pumping geometry. Other types of lasers can be used such as a fiber laser or a gas laser.

[0044] In particular implementations, the laser source 102 is an infrared laser source configured to operate at infrared (IR) wavelengths for removing sections of lithium on lithium coated substrates. The laser source 102 may generate a pulsed laser beam 130. In the implementations described herein, frequency, pulse width, and pulse energy of the laser beam 130 generated by the laser source 102 are tunable (e.g., adjustable) depending on the material being removed, targeted lateral dimensions of the sections being removed, as well as a depth of the removal. Additionally, the movement speed of the laser beam 130, number of pulses, and beam profile and focused spot size may be tuned.

[0045] In any form, the laser beam 130 produced by the laser source 102 is projected (e.g., transmitted) towards the flexible support layer stack 140 via the optical source assembly 106. The optical source assembly 106 is optically coupled with the laser source 102 and includes any suitable image projection devices for directing the laser beam 130 towards the flexible support layer stack 140 for laser activation. In particular implementations, the optical source assembly 106 includes a scanner 132, such as a single- or multi-axis large angle galvanometer optical scanner (i.e., galvanometer scanner). The term “galvanometer scanner” refers to any device that responds to an electronic signal from the controller 110 to change a projection orreflection angle of the laser beam 130 to sweep the laser beam 130 across the flexible support layer stack 140. Scanner 132 may also be a polygon scanner, an electrooptic scanner, an acousto-optic, or a combination thereof. Utilization of the scanner 132 enables activation of multiple sections of lithium on the flexible support layer stack 140 simultaneously via the laser lift-off process, in addition to scanning of the laser beam 130 across a surface of the flexible support layer stack 140 without mechanical translation of the flexible support layer stack 140 itself. The scanner 132 may further include any suitable features to facilitate activation of the materials and structures described herein, such as digital servo feedback, low drift, fast dynamic response, and precise calibration capability.

[0046] In one or more implementations, which can be combined with other implementations, the optical source assembly 106 further includes one or more scan lenses 134 having a large field of view that encompasses the entirety of the flexible support layer stack 140. In one or more implementations, which can be combined with other implementations, two or more scan lenses 134 may be utilized for laser removal of different types of materials, each scan lens of the scan lenses 134 specific to a wavelength range of the laser source 102. The scan lenses 134 may be telecentric lenses, F-theta lenses, or a combination thereof. During operation, the laser beam 130 projected by the optical source assembly 106 is directed towards the back surface 140b of the flexible support layer stack 140.

[0047] The cutting system 100 further includes the pickup roller 108 for removing lithium metal from the lithium film 214 that has been exposed to the laser beam 130 from the flexible support layer 212. The pickup roller 108 is positioned to contact the lithium film 214 on the front surface 140f of the flexible support layer stack 140. The pickup roller 108 may be positioned opposite the optical source assembly 106, which produces the laser beam 130. Although the pickup roller 108 is shown as being aligned with the optical source assembly 106, the pickup roller 108 may be positioned downstream from the optical source assembly 106 and on the opposite side of the flexible support layer 212. The pickup roller 108 can be or include any suitable material that can adhere to and remove lithium metal. The material of pickup roller 108 can be selected from any suitable metallic or polymer material. In one example, the pickup roller 108 can be or include stainless steel.

[0048] In one or more implementations, which can be combined with other implementations, the cutting system further includes a scraping tool, for example, a doctor blade 170. The doctor blade 170 is positioned to remove lithium metal film present on the pickup roller 108. As the pickup roller 108 removes activated lithium metal from the lithium film 214, the removed lithium metal film accumulates on the surface of the pickup roller 108. The doctor blade 170 removes the accumulated lithium metal film from the surface of the pickup roller 108 providing a clean surface form additional lithium metal to adhere to.

[0049] In one or more implementations, which can be combined with other implementations, the cutting system 100 further includes a sacrificial film 113, for example, a plastic film, for removing lithium metal from the lithium film 214 that has been exposed to the laser beam 130 from the flexible support layer 212. Referring to FIG. 1A, the pickup roller 108 pushes the sacrificial film 113 against the activated lithium metal of the lithium film 214, and the activated lithium metal adheres to the sacrificial film 113 and is removed from the flexible support layer 212. In some implementations, as depicted in FIG. 1A, the cutting system 100 further includes a sacrificial film supply roller 109 for supplying the sacrificial film 113 and a sacrificial film collection roller 111 for collecting the sacrificial film 113. As depicted in FIG. 1A, the sacrificial film 113 winds around the pickup roller 108 and the pickup roller 108 pushes the sacrificial film 113 against the activated lithium metal film, the activated lithium metal film adheres to the sacrificial film 113, and the sacrificial film 113 with the lithium metal adhered thereto is collected by the sacrificial film collection roller 111. In some implementations, the activated lithium metal is contacted by the pickup roller 108 without the sacrificial film 113 and adheres directly to the pickup roller 108.

[0050] The cutting system 100 further includes the blade 118. The blade 118 is positioned to cut or slit portions of the flexible support layer along a targeted path, for example, a portion of the flexible support layer 212 that has been exposed by removal of lithium metal from the lithium film 214. The blade 118 is positioned downstream from the optical source assembly 106 and the pickup roller 108. The blade 118 may be any blade suitable for cutting or slitting the flexible support layer 212. The blade 118 may be a stationary blade, a rotary blade, a reciprocating blade, or other suitable mechanical cutting mechanism. The blade 118 may be in the form of a die. The die can be configured to cut the flexible support layer 212 in a closed shape. In one ormore implementations, which can be combined with other implementations, the blade 118 is positioned on a blade stage 116 or other support structure. The blade stage 116 may be coupled to an optical bench 114. The blade 118 may be positioned such that the flexible support layer stack 140 reaches the blade 118 after removal of the lithium metal from the lithium film 214 by the optical source assembly 106 and pickup roller 108. For example, the blade 118 can cut the flexible support layer 212 parallel to the travel direction shown by arrow 103 of the flexible support layer stack 140. The blade 118 can cut the flexible support layer 212 across the width of the flexible support layer 212 for example, perpendicular to the travel direction shown by arrow 103 of the flexible support layer stack 140. In one or more implementations, which can be combined with other implementations, the blade 118 can move along the z-axis, the x-axis, and the y-axis.

[0051] The blade 118 can be or include any suitable material for cutting the flexible support layer 212. In one or more implementations, which can be combined with other implementations, the blade 118 can be or include a metal such as titanium, aluminum, steel, or a combination thereof. In one or more implementations, which can be combined with other implementations, the blade 118 can be or include a polymer, for example, a hard polymer. In one or more implementations, which can be combined with other implementations, the blade 118 can be or include a ceramic material. Other materials are possible. In some implementations, the blade 118 can be serrated. However, in other implementations, the blade 118 is free of serrations.

[0052] The cutting system 100 can further include the controller 110. The controller 110 can include a central processing unit (CPU) (not shown), memory (not shown), and support circuits (or I / O) (not shown). The CPU may be one of any form of computer processors that are used in industrial settings for controlling various processing and hardware (e.g., laser sources, optical assemblies, scanners, stage motors, and other hardware) and monitor the processes (e.g., processing time, stage and / or wafer nest position, and substrate position). The memory (not shown) is connected to the CPU, and may be one or more of readily available memory, such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or any other form of digital storage, local or remote. Software instructions and data can be coded and stored within the memory for instructing the CPU. The support circuits (not shown) are also connected to the CPU for supporting the processor in aconventional manner. The support circuits may include conventional cache, power supplies, clock circuits, input / out circuitry, subsystems, and the like. A program (or computer instructions) readable by the controller 110 determines which tasks are performable on the flexible support layer stack 140. The program may be software readable by the controller 110 and may include code to monitor and control (e.g., switch between), for example, the laser beam 130 characteristics (frequency, pulse width, and pulse energy) and movement of the scanner 132.

[0053] FIG. 1 B illustrates a schematic diagram of another exemplary cutting system 160 for cutting or slitting metals in accordance with one or more implementations of the present disclosure. The cutting system 160 is similar to the cutting system 100. However, the cutting system 160 replaces the blade 118 shown in FIG. 1 A with a second optical source assembly 152 and a second laser source 150. The laser source 150 is configured to generate a laser beam 154 and the optical source assembly 152 is configured to direct the laser beam 154 toward the front surface 140f of the flexible support layer stack 140, for example, the frontside 212f of the flexible support layer 212. The second laser source 150 is configured to generate a second laser beam 154 for cutting or slitting portions of the flexible support layer 212 along a targeted path, for example, a portion of the flexible support layer 212 that has been exposed by removal of lithium metal from the lithium film 214.

[0054] The cutting system 160 may further include the second optical source assembly 152. The second optical source assembly 152 may include a scanner 156 and a scan lens 158. Although the second optical source assembly 152 is shown in FIG. 1 B as positioned to direct the second laser beam 154 toward the front surface 140f of the flexible support layer stack 140, the second optical source assembly 152 may be positioned to direct the laser beam toward the back surface 140b of the flexible support layer stack 140.

[0055] The second optical source assembly 152 may be positioned such that the flexible support layer stack 140 reaches the second laser beam 154 after removal of the lithium metal from the lithium film 214 by the optical source assembly 106 and the pickup roller 108. For example, the second laser beam 154 can cut the flexible support layer 212 parallel to the travel direction shown by arrow 103 of the flexible support layer stack 140. The second laser beam 154 can cut the flexible support layer212 across the width of the flexible support layer 212 for example, perpendicular to the travel direction shown by arrow 103 of the flexible support layer stack 140.

[0056] The second laser source 150 may generates the second laser beam 154. In the implementations described herein, frequency, pulse width, and pulse energy of the second laser beam 154 generated by the second laser source 150 are tunable (e.g., adjustable) depending on the material being cut, targeted lateral dimensions of the sections being cut, as well as a depth of the cut. Additionally, the movement speed of the second laser beam 154, number of pulses, and beam profile and focused spot size may be tuned.

[0057] In any form, the second laser beam 154 produced by the second laser source 150 is projected (e.g., transmitted) towards the flexible support layer stack 140 via the second optical source assembly 152. The second optical source assembly 152 is optically coupled with the second laser source 150 and includes any suitable image projection devices for directing the second laser beam 154 towards the flexible support layer stack 140 for laser activation. In particular implementations, the second optical source assembly 152 includes the scanner 156, such as a single- or multi-axis large angle galvanometer optical scanner (i.e., galvanometer scanner). The term “galvanometer scanner” refers to any device that responds to an electronic signal from the controller 110 to change a projection or reflection angle of the second laser beam 154 to sweep the second laser beam 154 across the flexible support layer stack 140. The scanner 156 may also be a polygon scanner, an electro-optic scanner, an acousto-optic, or a combination thereof. Utilization of the scanner 156 enables cutting of multiple sections of the flexible support layer 212 of the flexible support layer stack 140 simultaneously via the laser cutting, in addition to scanning of the second laser beam 154 across a surface of the flexible support layer stack 140 without mechanical translation of the flexible support layer stack 140 itself. The scanner 156 may further include any suitable features to facilitate cutting of the materials and structures described herein, such as digital servo feedback, low drift, fast dynamic response, and precise calibration capability.

[0058] In one or more implementations, which can be combined with other implementations, the second optical source assembly 152 further includes one or more scan lenses 158 having a large field of view that encompasses the entirety ofthe flexible support layer stack 140. In one or more implementations, which can be combined with other implementations, two or more scan lenses 158 may be utilized for laser cutting of different types of materials, each scan lens 158 specific to a wavelength range of the second laser source 150. The scan lenses 158 may be telecentric lenses, F-theta lenses, or a combination thereof. During operation, the second laser beam 154 projected by the second optical source assembly 152 is directed towards either the back surface 140b of the flexible support layer stack 140 or the front surface 140f of the flexible support layer stack 140.

[0059] In one or more implementations, which can be combined with other implementations, the second laser source 150 produces a CO2 laser. The CO2 laser has a wavelength suitable for cutting polymer materials. In some implementations, the CO2 laser has a wavelength of 10.6 micrometers or less, for example, 9.4 micrometers or 9.6 micrometers.

[0060] In one or more implementations, which can be combined with other implementations, the second laser source 150 produces a CO laser. The CO laser has a wavelength suitable for cutting polymer materials. In some implementations, the CO laser has a wavelength of 6 micrometers or less, for example in a range from about 5 micrometers to about 6 micrometers.

[0061] FIG. 2 illustrates a top plan view of a flexible support layer stack, for example, the flexible support layer stack 140, being processed in a cutting system, for example, the cutting system 100 in accordance with one or more implementations of the present disclosure. The flexible support layer stack 140 can be formed by any suitable deposition process. The flexible support layer stack 140 includes the flexible support layer 212. The flexible support layer stack 140 further includes the lithium film 214. The lithium film 214 can be formed on the frontside 212f, the backside 212r, or both the frontside 212f and the backside 212r of the flexible support layer 212.

[0062] The flexible support layer stack 140 shown in FIG. 2 can be, for example, a negative electrode for a secondary cell, such as a negative electrode or anode for a lithium battery. According to some examples described herein, a flexible negative electrode for a lithium battery includes the flexible support layer 212 that can be a current collector including copper and having a thickness of equal to or less than 10 pm, typically equal to or less than 8 pm, beneficially equal to or less than 7 pm,specifically equal to or less than 6 pm, in particular equal to or less than 5 pm. The flexible support layer stack 140 further includes a lithium film stack including lithium and having a thickness of equal to or more than 5 pm and / or equal to or less than 15 pm.

[0063] In one or more implementations, which can be combined with other implementations, the flexible support layer 212 may be a flexible conductive substrate which comprises, consists of, or consists essentially of a metal, such as copper (Cu) or nickel (Ni). Furthermore, the flexible support layer 212 can include one or more sub-layers. Examples of metals that the current collectors can be comprised of include aluminum (Al), copper (Cu), zinc (Zn), nickel (Ni), cobalt (Co), tin (Sn), silicon (Si), manganese (Mn), magnesium (Mg), alloys thereof, or combinations thereof. In particular implementations, the web or flexible support layer 212 may be or include a polymer material. The polymer material can be a resin film selected from a polypropylene film, a polyethylene terephthalate (PET) film, a polyphenylene sulfide (PPS) film, and a polyimide (PI) film.

[0064] In one or more implementations, which can be combined with other implementations, the flexible support layer 212 has a thickness equal to or less than about 25 pm, or equal to or less than 20 pm, or equal to or less than 15 pm, or equal to or greater than 3 pm, or equal to or greater than 5 pm. In one example, the flexible support layer 212 has a thickness in a range from about 4.5 pm to about 10 pm. The flexible support layer 212 can be thick enough to provide the intended function and can be thin enough to be flexible. Specifically, the flexible support layer 212 can be as thin as possible so that the flexible support layer 212 can still provide its intended function. The flexible support layer 212 can have a width equal to or less than about 3000 millimeters, for example, in a range from about 100 millimeters to about 2400 millimeters, or in a range from about 1200 millimeters to about 2000 millimeters. The flexible support layer 212 can have a width equal to or less than about 1200 millimeters, for example, in a range from about 100 millimeters to about 1200 millimeters.

[0065] In one or more implementations, which can be combined with other implementations, the lithium film 214 can have a thickness of equal to or less than 20 pm, or equal to or less than 8 pm, or equal to or less than 7 pm, or equal to or lessthan 6 pm, or equal to or less than 5 pm. In one example, the lithium film 214 has a thickness in a range from about 1 pm to about 20 pm.

[0066] The flexible support layer stack 140 can be cut or slit using the combination laser and blade systems and methods described herein, for example, the cutting system 100. The flexible support layer stack 140 can be a lithium metal anode structure, for example, a lithium film formed on a PET substrate. The flexible support layer stack 140 can be a lithiated or pre-lithiated anode structure. The flexible support layer stack 140 shown in FIGS. 2 and 3A-3C includes the flexible support layer 212 or web having a lithium film stack or lithium film 214 formed thereon. During processing, the flexible support layer 212 is transported in the travel direction shown by arrow 103. In one implementation, which can be combined with other implementations, the lithium film stack or lithium film 214 is a lithium metal film. In another implementation, which can be combined with other implementations, the lithium film stack includes a lithium metal film and additional films, for example, an anode film such as a graphite film with the lithium metal film formed thereon.

[0067] Each lithium film 214 includes a lithium film and optionally additional films. Although the lithium film 214 in FIG. 2 and FIGS. 3A-3C is shown as a single layer on the frontside 212f of the flexible support layer 212, it should be understood by those of ordinary skill in the art that the lithium film 214 can be a lithium film stack can including a greater number of layers, which can be provided over, under and / or between the flexible support layer 212 and the lithium film 214. Although shown as a single-sided structure, it should be understood by those of ordinary skill in the art that the flexible support layer stack 140 can also be a double-sided structure with the lithium film 214 formed on the frontside 212f of the flexible support layer 212 and a second lithium metal film stack (not shown) formed on the backside 212r of the flexible support layer 212.

[0068] The source roll 120 including the flexible support layer stack 140 may be placed on the supply roller 101. The flexible support layer stack 140 may be fed to the cutting system 100. A laser beam 130 activates one or more portions of the lithium film 214 followed by removal of the one or more activated portions of the lithium film 214 from the flexible support layer 212 using the pickup rollers 108a-b (collectively 108) to produce at least one blade cutting zone 216a-b of width “L1” between two ormore segments 214a, 214b, 214c of each of the one or more lithium films 214. The at least one blade cutting zones 216a-b are shown in FIG. 2 as being located at one- third of the width of the flexible support layer stack 140 from an edge of the lithium film 214, but may be located at any targeted position on the flexible support layer stack 140. For example, the at least one blade cutting zone 216a-b may be located along a longitudinal centerline of the flexible support layer stack 140. The width “L” created by the laser beam 130 and the pickup rollers 108a-b should be greater than a width of the blade 118a-b, such as about 5 mm or less, such as about 3 mm or less, such as about 1 mm or less, such as about 0.1 mm or less. After removal of the portion of the activated lithium metal, the flexible support layer stack 140 undergoes blade cutting at the blade 118a-b. The blade 118a-b cuts the flexible support layer 212 within the at least one blade cutting zone 216a-b. Preferably, the blade 118a-b cuts the flexible support layer 212 on a centerline of the blade cutting zone 216a-b. The blade cutting produces two or more slit rolls 122a-c, such as a first slit roll 122a, a second slit roll 122b, and a third slit roll 122c.

[0069] FIG. 3A illustrates a cross-sectional side view of the flexible support layer stack 140 taken along line 3A-3A of FIG. 2 before laser activation, lithium removal, and blade cutting, in accordance with one or more implementations of the present disclosure. The flexible support layer stack 140 includes the lithium film 214 formed on the frontside 212f of the flexible support layer 212. Although a single lithium film is shown in FIG 3A, additional lithium metal films are contemplated, for example, a second lithium metal film positioned on the backside 212r of the flexible support layer 212.

[0070] FIG. 3B illustrates a cross-sectional side view of the flexible support layer stack 140 taken along line 3B-3B of FIG. 2 after a laser activation process but before removal of the activated lithium metal. As shown in FIG. 3B, one or more portions of the one or more lithium films 214 is activated by the laser beam to form activated lithium metal portions 302a-b.

[0071] FIG. 3C illustrates a cross-sectional side view of the flexible support layer stack 140 taken along line 3C-3C of FIG. 2 after removal of the activated lithium metal from the flexible support layer stack 140 and prior to blade cutting. As shown in FIG. 3C, a portion of each of the one or more lithium films 214 are removed by the pickuprollers 108-b from the frontside 212f of the flexible support layer 212, creating the blade cutting zones 216a-b in each of the one or more lithium films 214. The blade cutting zone 216a separates a segment 214a from a segment 214b by a width “L” and the blade cutting zone 216b separates the segment 214b from a segment 214c by a width “L”.

[0072] FIG. 3D illustrates a cross-sectional view of the flexible support layer stack 140 taken along line 3D-3D of FIG. 2 after the blade cutting process. The blades 118a-b slits the flexible support layer 212 into three substrate segments 212a-c that are rolled into a first slit roll 122a, a second slit roll 122b, and a third slit roll 122c.

[0073] Laser parameters selection, such as pulse width, can be integral to developing a successful combination laser lift-off and blade cutting process that minimizes damage to the underlying substrate during the laser lift-off process while achieving clean blade cutting lanes. A high frequency nanosecond-pulsed IR laser or picosecond-pulsed IR laser can be used based on laser-material interaction specific to lithium material stacks. Lithium is very unique in that its melting temperature is only 453.65 K (180.50 °C) while the boiling temperature is 1603 K (1330 °C), which is still very high. In comparison, PET has a melting temperature of 523 K (250 °C), and a boiling temperature 623 K (350 °C). For a conductive substrate such as copper, it has a much lower absorption to IR laser than to green (~520 — 540 ns) or UV laser (< 360 nanometer). For example, at ambient temperature, a 1064 nanometer laser has less than 5% optical absorption in copper, while a 532 nanometer Green laser has about 40% optical absorption in copper. The 1064 nanometer laser in a melted copper liquid still has about 5% optical absorption. From the aspect of avoiding copper damage, the 1 pm IR laser wavelength is more advantageous than a Green or UV laser wavelength. In addition, at the same average power level and with the same type of laser, an IR laser is more reliable and cost-effective.

[0074] An IR nanosecond laser with a pulse duration of less than 30 nanoseconds and a near-infrared wavelength of 1064 nanometer is more suitable for this LLO process. However, ultrashort pulsed lasers may be used for some purposes like quality improvement. The laser with a longer pulse duration generates a higher density plasma resulting in a greater gas pressure to release the interface between PET and lithium. However, pulse duration longer than 50 nanosecond involves muchhigher pulse energy (or laser power) due to a low peak power. On the contrary, a shorter pulse duration can process precisely so that it can achieve a cleaner lithium edge.

[0075] Laser parameters can be selected with benefits and advantages such as providing sufficiently high laser intensity to achieve removal of lithium and to minimize damage to the underlying substrate. Also, parameters can be selected to provide meaningful process throughput for industrial applications with precisely controlled ablation width (e.g., kerf width) and depth. As described above, an ultrashort pulse (USP) laser (e.g., a laser with a pulse duration of, at most, in a femtosecond range) such as a femtosecond or picosecond pulse laser is suitable for providing such advantages. Such pulse width ranges for UPS may be 5 fs to 999 fs, preferably 10 fs to 999 fs for a femtosecond pulse laser and 1 ps to 10 ps for a picosecond pulse laser. Regarding USPs, a shorter pulse width results in higher peak power and fewer thermal effects. This increases the control over the removal rate. For example, a 10 fs pulse has 1000 times higher peak power than 10 ps pulse of the same pulse energy. Therefore, the wavelength range is of less importance as ablation may be ceased at a precise depth, removing the specific amount or thickness of lithium without thermally damaging the underlying substrate.

[0076] However, nanosecond-pulse laser lift-off is also suitable, as pulses longer than a few tens of picoseconds will start having more pronounced thermal effects. Nanosecond pulse lasers are also more cost-effective, although certain wavelengths may provide better performance than others. For a PET substrate, a wavelength range of about 450 nm to about 1600 nm, or from about 450 nm to about 1550 nm, will facilitate laser lift-off of lithium with nanosecond pulses such that the PET film is highly transparent to light. A wavelength of less than 450 nm, or less than 355 nm, will result in scribing or cutting of the PET substrate. For a polyimide (PI) substrate, a wavelength in a range from about 700 nm to about 1700 nm, or in a range from about 750 nm to about 1600 nm, will provide laser lift-off of lithium using nanosecond pulses. Similarly, a wavelength of less than 450 nm will scribe or cut the PI substrate.

[0077] The nanosecond pulses may range in a range from about 1 ns to about 200 ns, or in a range from about 1 ns to about 50 ns, or in a range from about 1 ns to about 10 ns. For example, in one implementation, a nanosecond-pulse laser process havinga wavelength closer to or in the IR range provides a cleaner ablation process than a nanosecond-pulse laser process having a wavelength closer to or in the UV range. In a specific such implementation, a femtosecond-pulse laser process suitable for semiconductor wafer or substrate scribing is based on a laser having a wavelength of approximately greater than or equal to one micrometer. In a particular such implementation, pulses of approximately less than or equal to 15 nanoseconds of the laser having the wavelength of approximately greater than or equal to one micrometer are used. However, in an alternative implementation, dual laser wavelengths (e.g., a combination of an IR laser and a UV laser) can be used.

[0078] The previously described implementations of the present disclosure have many advantages, including decreased slitting defects where the cutting blade is not collecting reactive metal or alloy films. Safe removal of sticky reactive metal or alloy before slitting or cutting increases the cutting blade lifetime and increases the time between maintenance cycles. Reduces or eliminates the periodic maintenance often used to eliminate particle debris build-up on the cutting blade enabling long slitting of the web without periodic maintenance. However, the present disclosure does not necessitate that all the advantageous features and all the advantages need to be incorporated into every implementation of the present disclosure.

[0079] In the Summary and in the Detailed Description, and the Claims, and in the accompanying drawings, reference is made to particular features (including method operations) of the present disclosure. It is to be understood that the disclosure in this specification includes all possible combinations of such particular features. For example, where a particular feature is disclosed in the context of a particular aspect, implementation, or example of the present disclosure, or a particular claim, that feature can also be used, to the extent possible in combination with and / or in the context of other particular aspects and implementations of the present disclosure, and in the present disclosure generally.

[0080] Implementations and all of the functional operations described in this specification can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structural means disclosed in this specification and structural equivalents thereof, or in combinations of them. Implementations described herein can be implemented as one or more non-transitorycomputer program products, i.e. , one or more computer programs tangibly embodied in a machine readable storage device, for execution by, or to control the operation of, data processing apparatus, e.g., a programmable processor, a computer, or multiple processors or computers.

[0081] The processes and logic flows described in this specification can be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).

[0082] The term "data processing apparatus" encompasses all apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, or multiple processors or computers. The apparatus can include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer.

[0083] Computer readable media suitable for storing computer program instructions and data include all forms of nonvolatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto optical disks; and CD ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

[0084] The term “comprises” and grammatical equivalents thereof are used herein to mean that other components, ingredients, operations, etc. are optionally present. For example, an article “comprising” (or “which comprises”) components A, B, and C can consist of (i.e., contain only) components A, B, and C, or can contain not only components A, B, and C but also one or more other components. In addition, whenever a composition, an element or a group of elements is preceded with thetransitional phrase “comprising” or grammatical equivalents thereof, it is understood that it is contemplated that the same composition or group of elements may be preceded with transitional phrases “consisting essentially of,” “consisting of,” “selected from the group of consisting of,” or “is” preceding the recitation of the composition, element, or elements and vice versa.

[0085] Where reference is made herein to a method comprising two or more defined operations, the defined operations can be carried out in any order or simultaneously (except where the context excludes that possibility), and the method can include one or more other operations which are carried out before any of the defined operations, between two of the defined operations, or after all of the defined operations (except where the context excludes that possibility).

[0086] When introducing elements of the present disclosure or exemplary aspects or implementation(s) thereof, the articles “a,” “an,” “the” and “said” are intended to mean that there are one or more of the elements.

[0087] While the foregoing is directed to implementations of the present disclosure, other and further implementations of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

What is claimed is:1 . A system for slitting a flexible support layer stack, comprising: a laser source configured to generate a laser beam, the laser beam directed toward a first surface of a flexible support layer stack; an optical scanner configured to direct the laser beam toward the first surface of the flexible support layer stack; a pickup roller positioned opposite the laser beam, the pickup roller positioned to contact a second surface of the flexible support layer stack, the second surface opposite the first surface; and a cutting assembly positioned downstream of the laser beam.

2. The system of claim 1 , wherein the laser source is an infrared laser source.

3. The system of claim 1 , wherein the flexible support layer stack has an alkali metal film formed on the first surface.

4. The system of claim 3, wherein the flexible support layer stack comprises a polymer material selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), poly(methyl methacrylate) (PMMA), cellulose triacetate (TAC), polypropylene (PP), polyethylene (PE), polycarbonates (PC), multilayers thereof, or a combination thereof.

5. The system of claim 1 , wherein the cutting assembly comprises a rotary blade.

6. The system of claim 5, wherein the cutting assembly further comprises a blade stage.

7. The system of claim 1 , wherein the cutting assembly comprises: a second optical scanner configured to direct a second laser beam toward the flexible support layer stack.

8. The system of claim 1 , further comprising a supply roller for supplying the flexible support layer stack and a take-up roller for collecting the cut flexible support layer stack.

9. The system of claim 1 , wherein the pickup roller comprises stainless steel.

10. A slitting apparatus comprising: a laser unit comprising; an optical assembly; a laser source coupled to the optical assembly; and a controller coupled to the optical assembly; a blade assembly positioned downstream of the laser unit; and a pickup roller positioned upstream from the blade assembly and opposite the optical assembly.11 . The slitting apparatus of claim 10, wherein the laser source is a solid-state laser configured to produce a continuous laser beam.

12. The slitting apparatus of claim 10, wherein the laser source is a solid-state laser configured to produce a pulsed laser beam.

13. The slitting apparatus of claim 10, wherein the blade assembly comprises a rotary blade.

14. The slitting apparatus of claim 13, wherein the pickup roller comprises stainless steel.

15. A method of slitting a coated substrate, comprising: feeding a coated substrate comprising of at least one coating layer and a substrate layer to a laser unit; exposing a blade cutting area on the coated substrate by activating a section of the at least one coating layer from the substrate layer of the coated substrate; removing the activated section of the at least one coating layer; subsequently feeding the coated substrate to a blade assembly; andslitting the coated substrate using the blade assembly within the blade cutting area.

16. The method of claim 15, wherein the laser unit comprises: an optical assembly; a laser source coupled to the optical assembly; an optical bench positioned opposite the optical assembly; and a controller coupled to the optical assembly.

17. The method of claim 15, wherein the coating layer comprises lithium.

18. The method of claim 15, wherein the substrate layer comprises a flexible substrate further comprising polyethylene terephthalate, polyimide, polyphenylene sulfide, alloys thereof, or combinations thereof.

19. The method of claim 15, wherein the substrate layer comprises a flexible conductive substrate further comprising copper, nickel, aluminum, zinc, cobalt, tin, silicon, manganese, magnesium, alloys thereof, or combinations thereof.

20. The method of claim 15, wherein the blade cutting area is at least one longitudinal section of the coated substrate configured to produce at least two slit coated substrates.

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