Coiled material coating method and ventilation cooling drum with integrated electrostatic adsorption

Abstract

A rotatable drum is provided to support a substrate. The rotatable drum includes a curved drum surface for supporting a substrate. The curved drum surface includes a dielectric portion and an electrode connected to a power source. The electrodes are electrically connected to the curved drum surface and can adsorb and release the substrate in one or more circumferential sections of the curved drum surface.

Description

Technical Field

[0001]

[0014] Embodiments described herein generally relate to apparatus and methods for making metal electrodes, more particularly lithium-containing anodes, and high-performance electrochemical devices, such as primary and secondary electrochemical devices, including such lithium-containing electrodes. Background Art

[0002] Lithium (Li)-ion batteries have played a vital role in the development of the current generation of mobile devices, microelectronics, and electric vehicles. A typical Li-ion battery consists of a positive electrode (cathode), a negative electrode (anode), an electrolyte for electrical conductivity, a porous separator (electrical insulator) between the two electrodes to keep them physically separated, and packaging.

[0003] Methods for depositing lithium on substrates, such as large, flexible substrates, can be temperature sensitive and lead to the formation of wrinkles and other defects. The substrate can be guided and supported on a rotatable coating drum with a curved drum surface. Vapor can be deposited on the substrate as the substrate moves over the curved surface of the rotatable drum, passing over an evaporation source. The drum can be used to maintain and control the temperature of the substrate by cooling and pressurizing the back of the substrate, using high pressure to maintain a uniform gap height between the substrate and the curved drum surface. Low pressure can be used for wide film substrates because wrinkles in the machine direction can be caused by particles, film stress, or misalignment.

[0004] Therefore, it is desirable to provide apparatus and methods to maintain low pressure and enhance substrate cooling to improve throughput. Summary of the Invention

[0005] In one aspect, a rotatable drum is provided for supporting a substrate. The rotatable drum includes a curved drum surface for supporting the substrate and a dielectric portion. The rotatable drum also includes electrodes connected to a power source, the electrodes being electrically connected to the curved drum surface and capable of attracting and releasing the substrate in one or more circumferential segments of the curved drum surface.

[0006] Embodiments may include one or more of the following. The dielectric portion comprises a material selected from the group consisting of diamond-like carbon, aluminum oxide, boron nitride, polyimide, and combinations thereof. The electrode is a fixed electrode spaced radially inward from the curved drum surface and electrically connected to the curved drum surface via a plurality of movable electrode spokes. The electrode comprises a first hemisphere connected to ground and a second hemisphere connected to a power source. Each of the one or more circumferential segments comprises at least one cooling channel and one or more gas channels extending from the inner surface of the circumferential segment to the curved drum surface. The dielectric portion on the curved drum surface comprises a first polyimide layer, a pattern electrode disposed on the first polyimide layer, and a second polyimide layer disposed on the pattern electrode. The pattern electrode comprises copper. The pattern electrode comprises a plurality of mesas. The mesas are polygonal in shape. The mesas are arranged in rows extending from one edge of the rotatable drum to the opposite edge of the rotatable drum. The rotatable drum further comprises surface channels disposed between adjacent rows of pattern electrodes. The rows are arranged alternately, with the first row connected to the power source and the second row connected to ground. The rotatable drum further includes a heat sink disposed radially inside the curved drum surface and radially outside the electrode. A vapor deposition device includes the rotatable drum and an evaporation source configured to deposit material onto a substrate disposed on the curved surface of the rotatable drum.

[0007] In another aspect, an electrode assembly for electrostatically adsorbing a substrate to a rotatable drum is provided. The electrode assembly includes a first protective layer in contact with the rotatable drum, an electrode disposed on the first protective layer, and a second protective layer disposed on the electrode, the protective layer including a curved surface for supporting the substrate.

[0008] Embodiments may include one or more of the following: The first and second protective layers comprise aluminum oxide, and the electrodes comprise aluminum or an aluminum alloy. The electrodes are arranged in a plurality of rows that are generally parallel to one another and extend from one edge of the rotatable drum to an opposite edge of the rotatable drum. The rows are arranged alternately, with one row connected to power and the other to ground, and channels are provided between the rows.

[0009] In another aspect, a method for coating a substrate in a vacuum chamber is provided. The method includes conveying the substrate onto a curved surface of a rotatable drum, where the substrate is electrostatically attached to a portion of the curved surface of the rotatable drum. The method further includes evaporating a material in an evaporation crucible. The method further includes directing the evaporated material from the evaporation crucible toward the substrate.

[0010] Embodiments may include one or more of the following. Transporting the substrate further includes holding the substrate on the curved surface of the rotatable drum so that a gap is formed between the substrate and the curved surface of the rotatable drum. The method further includes supplying gas into the gap between the back of the substrate and the curved surface of the rotatable drum. The substrate is transported in a machine direction, extending from an inlet side to an outlet side of the rotatable drum, with the substrate being attracted at the inlet side and released at the outlet side.

[0011] In another aspect, a non-transitory computer-readable medium stores instructions that, when executed by a processor, cause the process to perform the operations of the apparatus and / or method described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to provide a more detailed understanding of the features disclosed above, the disclosure briefly summarized above will be described in more detail with reference to exemplary embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of the scope thereof, which may include other equally effective embodiments.

[0013] Figure 1 A schematic cross-sectional view of an energy storage device including an anode electrode structure is shown according to certain embodiments described herein.

[0014] Figure 2 A cross-sectional view of a double-sided anode electrode structure according to certain embodiments described herein is shown.

[0015] Figure 3 A schematic cross-sectional view of an evaporation source for depositing evaporated material on a substrate according to certain embodiments described herein is shown.

[0016] Figure 4 A schematic cross-sectional view of a vapor deposition apparatus according to certain embodiments described herein is shown.

[0017] Figure 5A shows a schematic diagram according to some embodiments described herein. Figure 4 Schematic diagram of a vapor deposition apparatus viewed along the rotation axis of a rotatable drum.

[0018] Figure 5B A cross-sectional end view of a rotatable drum transporting a substrate is shown according to certain embodiments described herein.

[0019] Figure 6 A cross-sectional view of a portion of a dielectric portion of a rotatable drum is shown, according to certain embodiments described herein.

[0020] Figure 7 A top view of a dielectric portion of a rotatable drum is shown, according to certain embodiments described herein.

[0021] Figure 8 A cross-sectional end view of a dielectric portion coupled to a main body of a drum is shown, according to certain embodiments described herein.

[0022] Figure 9 Shown is an interior view of a drum according to certain embodiments described herein.

[0023] Figure 10 A flow chart illustrating a method of coating a substrate according to certain embodiments described herein is shown.

[0024] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements in the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. DETAILED DESCRIPTION

[0025] The present disclosure relates generally to apparatus and methods for making metal electrodes, and more particularly, lithium-containing anodes, high performance electrochemical devices, such as primary and secondary electrochemical devices, including such lithium-containing electrodes.

[0026] Evaporation systems used to coat a web-like substrate guided on a rotatable coating drum are referred to herein as roll-to-roll (R2R) deposition systems. As used herein, flexible substrates may include films, foils, webs, strips of plastic material, metal, paper, or other materials. In general, the terms "web," "foil," "strip," and "substrate" are used interchangeably.

[0027] Energy storage devices, such as lithium-ion batteries, typically include a positive electrode, such as a cathode, and a negative electrode, such as an anode, separated by a polymer separator and a liquid electrolyte. Solid-state batteries also typically include a positive electrode and a negative electrode, but the polymer separator and the liquid electrolyte are replaced by ion-conducting materials. Lithium is deposited on a substrate, such as graphite coated copper foil or copper foil, by evaporating molten lithium or lithium vapor. When lithium is deposited on the front side of the substrate, the substrate is maintained below a certain temperature. Maintaining the temperature can include cooling the back of the substrate by ventilating a gas between the drum surface supporting the substrate and the substrate. The deposition rate of lithium on the substrate is limited by the cooling rate of the back of the substrate. The cooling gas should be selected so that it does not react with lithium. In some embodiments, the cooling gas can be or include argon, helium, or a combination thereof.

[0028] In addition to providing cooling air to the backside of the substrate, a uniform gap distance is typically maintained between the substrate and the drum surface. Traditional substrate retention solutions include mechanical solutions, such as retaining rollers placed around the drum to hold the substrate against the drum to prevent it from bulging out of the drum due to thermal expansion when air is applied. These solutions can lead to edge damage and peeling. It has been discovered that using electrostatic adsorption can retain the substrate on the drum while also maintaining a uniform gap between the substrate and the drum surface.

[0029] Figure 1 A schematic cross-sectional view of one embodiment of an energy storage device 100 is shown, the device including an anode electrode structure 110 formed according to the embodiments described herein. The anode electrode structure 110 includes an anode film 170 having one or more protective films 180 formed thereon. The energy storage device 100 can be a solid-state energy storage device or a lithium-ion based energy storage device. Although the energy storage device 100 is shown as a planar structure, it can also be formed into a cylindrical shape by rolling up a stack of layers; in addition, other unit configurations can also be formed, such as a prismatic unit, a button unit, or a laminated electrode unit. The energy storage device 100 includes an anode electrode structure 110 and a cathode electrode structure 120, optionally with an electrolyte or polymer separator 130 disposed therebetween. The cathode electrode structure 120 includes a cathode current collector 140 and a cathode film 150.

[0030] In one or more embodiments, which may be combined with other embodiments, the one or more protection films 180 include one or more ceramic materials. The ceramic material may be an oxide. In one embodiment, the protective films 180 include a material selected from the following materials, for example, aluminum oxide (Al2O3), aluminum oxynitride, aluminum nitride (AlN, aluminum deposited in a nitrogen environment), aluminum hydroxide ((AlO(OH))) (for example, amorphous ((α-AlO(OH))), diamond (γ-AlO(OH)) or catalite (5Al2O3·H2O)), calcium carbonate (CaCO3), titanium dioxide (TiO2), SiS2, SiPO4, silicon oxide (SiO2), zirconium oxide (ZrO2), hafnium oxide (HfO2), MgO, TiO2, Ta2O5, Nb2O5, LiAlO2, BaTiO3, boron nitride (BN), ion-conducting garnet, ion-conducting perovskite, ion-conducting antiperovskite, porous glass ceramics, etc., or a combination thereof. In a specific embodiment, the protective films 180 are deposited using the evaporation techniques described herein.

[0031] In one or more embodiments, which can be combined with other embodiments, each layer of the one or more protective films 180 is a coating or an independent film having a thickness of about 1 nm to about 3,000 nm (e.g., in the range of about 10 nm to about 600 nm; in the range of about 50 nm to about 100 nm; in the range of about 50 nm to about 200 nm; in the range of about 100 nm to about 150 nm).

[0032] The cathode electrode structure 120 includes a cathode current collector 140 with a cathode film 150 formed on the cathode current collector 140. It should be understood that the cathode electrode structure 120 may include other components or films.

[0033] The current collectors 140, 160 on the cathode film 150 and the anode film 170 can be the same or different electron conductors. In a specific embodiment, at least one of the current collectors 140, 160 is a flexible substrate. The flexible substrate can be or include one or more layers selected from plastic, polymer material, metallized plastic, metal, paper, multilayer material or a combination thereof. The flexible substrate can be or include cast polypropylene ("CPP") film, oriented polypropylene ("OPP") film or polyethylene terephthalate ("PET") film. Alternatively, the flexible substrate can be pre-coated paper, polypropylene (PP) film, polyethylene naphthalate (PEN) film, polylactic acid (PLA) film, polyimide (PI) film, poly(methyl methacrylate) (PMMA) film, triacetyl cellulose (TAC) film, polypropylene (PP) film, polyethylene (PE) film, polycarbonate (PC) film or PVC film. Examples of metals that the current collectors 140 and 160 may include include aluminum (Al), copper (Cu), zinc (Zn), nickel (Ni), cobalt (Co), manganese (Mn), chromium (Cr), stainless steel, cladding materials, alloys thereof, and combinations thereof. In one or more embodiments, which may be combined with other embodiments, at least one of the current collectors 140 and 160 is perforated. In one or more embodiments, which may be combined with other embodiments, at least one of the current collectors 140 and 160 includes a polymer substrate (e.g., polyethylene terephthalate ("PET") coated with a metal material). In one or more embodiments, which may be combined with other embodiments, the anode current collector 160 is a polymer substrate (e.g., a PET film) coated with copper. In another embodiment, the anode current collector 160 is a multi-metal layer located on a polymer substrate. The multi-metal layer may be or include copper, chromium, nickel, alloys thereof, or any combination thereof. In one embodiment, the anode current collector 160 is a multi-layer structure including a copper-nickel cladding material. In one embodiment, the multilayer structure includes a layer of nickel or chromium, a layer of copper formed on the first layer, and a layer of nickel, chromium, or both formed on the second layer. In one or more embodiments, which can be combined with other embodiments, the anode current collector 160 is nickel-coated copper. In one or more embodiments, which can be combined with other embodiments, the anode current collector 160 is graphite-coated copper. Furthermore, the current collector can have any physical dimensions (e.g., metal foil, sheet, or plate), shape, and micro / macro structure.

[0034] In one or more embodiments, which can be combined with other embodiments, the cathode current collector 140 can be or include aluminum. The cathode current collector 140 can be or include aluminum deposited on a polymer substrate, such as a PET film. The thickness of the cathode current collector 140 can be less than 50 μm, more specifically, 5 μm, or more specifically, 2 μm. The thickness of the cathode current collector 140 can be between about 0.5 μm and about 20 μm, for example, from about 1 μm to about 10 μm; from about 2 μm to about 8 μm; or from about 5 μm to about 10 μm. The anode current collector 160 can be or include copper. The anode current collector 160 can be or include stainless steel. In one or more embodiments, which can be combined with other embodiments, the thickness of the anode current collector 160 is less than 50 μm, more specifically, less than or about 5 μm, or more specifically less than or about 2 μm. In one or more embodiments, which can be combined with other embodiments, the anode current collector 160 has a thickness between about 0.5 μm and about 20 μm, for example, from about 1 μm to about 10 μm; from about 2 μm to about 8 μm; from about 6 μm to about 12 μm; or from about 5 μm to about 10 μm.

[0035] The cathode film 150 or cathode can be any material that is compatible with the anode and may include intercalation compounds, insertion compounds, or electrochemically active polymers.

[0036] The anode electrode structure 110 includes an anode current collector 160 , and an anode film 170 is formed on the anode current collector 160 . The anode electrode structure 110 may further include one or more protective films 180 .

[0037] In one or more embodiments, which can be used in combination with other embodiments, the anode film 170 is made of lithium metal, lithium metal foil, or lithium alloy foil (e.g., lithium aluminum alloy), or a mixture of lithium metal and / or lithium alloy with carbon (e.g., coke, graphite), nickel, copper, tin, indium, silicon, their oxides, or any combination thereof. The anode film 170 can be or include one or more lithium-containing intercalation compounds or lithium-containing insertion compounds. In specific embodiments, the anode film is a lithium metal film. In certain embodiments, when the anode film 170 is or includes lithium metal, the methods described herein can be used to deposit the lithium metal.

[0038] In one or more embodiments, which may be used in combination with other embodiments, the anode film 170 may be or include graphite, silicon, or any combination thereof. The anode film 170 may be or include one or more carbonaceous materials, such as natural or artificial graphite, partially graphitized or amorphous carbon, petroleum, coke, needle coke, and various intermediate phases, silicon-containing graphite, silicon, nickel, copper, tin, indium, aluminum, silicon, their oxides, combinations thereof, or mixtures of lithium metal and / or lithium alloys with carbon, such as coke or graphite, nickel, copper, tin, indium, aluminum, silicon, their oxides, or combinations thereof. In one embodiment, the anode film 170 may be or include silicon-graphite. In another embodiment, the anode film 170 may be or include graphite.

[0039] In one or more embodiments, which can be used in combination with other embodiments, when the anode film 170 is or includes graphite, silicon, or silicon-graphite, a layer of lithium is formed on the surface of the anode film 170. The thickness of this lithium metal layer is between about 20 μm and about 50 μm. This lithium layer can be a pre-lithiation layer.

[0040] In one or more embodiments (which may be combined with other embodiments), the thickness of the anode film 170 is from about 10 μm to about 200 μm, for example, from about 1 μm to about 100 μm; from about 10 μm to about 30 μm; from about 20 μm to about 30 μm; from about 1 μm to about 20 μm; or from about 50 μm to about 100 μm.

[0041] In one or more embodiments (which may be combined with other embodiments), the polymer membrane 130 is a porous polymer ion-conducting polymer substrate. The porous polymer substrate may be a multilayer polymer substrate. In a specific embodiment, the porosity of the porous polymer substrate ranges from about 20% to about 80% (e.g., between about 28% and about 60%). The average pore size range of the porous polymer substrate may be between about 0.02 μm and about 5 μm (e.g., about 0.08 μm to about 2 μm). In a specific embodiment, the Gurley number of the porous polymer substrate ranges from about 15 seconds to about 150 seconds. The porous polymer substrate may be or include one or more polyolefin polymers. Examples of suitable polyolefin polymers include polypropylene, polyethylene, or a combination thereof. In one or more embodiments, which may be combined with other embodiments, the porous polymer substrate is a polyolefin membrane. In one or more embodiments, which may be combined with other embodiments, the polyolefin membrane is a polyethylene membrane or a polypropylene membrane.

[0042] In one or more embodiments (which may be combined with other embodiments), the porous polymer substrate has a thickness ranging from about 1 μm to about 50 μm, for example, from about 3 μm to about 25 μm; from about 7 μm to about 12 μm; or from about 14 μm to about 18 μm.

[0043] Figure 2 A cross-sectional view of a double-sided anode electrode structure 210 formed according to one or more embodiments described herein is shown. The double-sided anode electrode structure 210 includes an anode current collector 160 having anode films 170a, 170b (collectively, 170) formed on opposite sides of the anode current collector 160. The double-sided anode electrode structure 210 further includes one or more protective films 180a, 180b (collectively, 180) formed on the anode films 170a, 170b, respectively.

[0044] Figure 3 FIG2 is a schematic cross-sectional view of an evaporation source 300 for depositing evaporated material onto a substrate 310 according to an embodiment described herein. The substrate 310 can be supported by a substrate support 313, such as the surface of a drum. The evaporation source 300 includes an evaporation crucible 330 for heating a source material 312 to a temperature above the evaporation or sublimation temperature of the source material 312, thereby evaporating the source material 312. The source material 312 can be a solid or liquid source material. The evaporation crucible 330 defines an interior volume 331, serving as a material reservoir, for accommodating the solid and / or liquid source material 312, and includes a first heater 335 for heating the interior volume 331 of the evaporation crucible 330, thereby evaporating the source material 312. For example, the source material 312 can be a metal, such as an alkali metal such as lithium or sodium, and the first heater 335 can be configured to heat the interior volume 331 of the evaporation crucible 330 to a temperature of approximately 600° C. or higher, particularly approximately 700° C. or higher, or approximately 800° C. or higher.

[0045] The evaporation source 300 further includes a vapor distributor 320 having a plurality of nozzles 321 for directing material evaporated in the evaporation crucible 330 toward the substrate 310, thereby depositing a coating 311 on the substrate 310. The vapor distributor 320 may include an interior volume 323 in fluid communication with the interior volume 331 of the evaporation crucible 330, such that the evaporated material can flow from the interior volume 331 of the evaporation crucible 330 to the interior volume 323 of the vapor distributor 320 via a vapor conduit 340, for example, along a linear connecting tube or channel. The plurality of nozzles 321 are configured to direct the evaporated material from the interior volume 323 of the vapor distributor 320 toward the substrate 310.

[0046] In some embodiments, the vapor distributor 320 may be a vapor distribution showerhead having a plurality of nozzles 321 arranged in a one-dimensional or two-dimensional pattern for directing the vaporized material toward the substrate 310 .

[0047] The evaporation crucible 330 is fluidically connected to the steam distributor 320 via a steam conduit 340 extending from the evaporation crucible 330 to the steam distributor 320 , with the conduit having a length direction A. During the evaporation process, the steam distributor 320 is typically set at a second temperature higher than the first temperature inside the evaporation crucible 330 to prevent condensation of material on the inner wall surface of the steam distributor 320 .

[0048] The evaporation source 300 may further include a first heater 335 for heating and evaporating the source material 312 in the interior volume 331 of the evaporation crucible 330, and a second heater 325 for heating the interior volume 323 of the vapor distributor 320. The first heater 335 and the second heater 325 may be independently controlled. For example, the first heater 335 may be configured to heat the evaporation crucible 330 to a first temperature, while the second heater 325 may be configured to heat the vapor distributor 320 to a second temperature that is different from the first temperature, particularly higher than the first temperature. During the vapor deposition process, the interior volume 323 of the vapor distributor 320 is typically hotter than the interior volume 331 of the evaporation crucible 330 to prevent condensation of the evaporated material on the inner walls of the vapor distributor 320. On the other hand, the majority of the interior volume 331 of the evaporation crucible 330 should be maintained near the evaporation temperature of the source material 312, for example, slightly below or slightly above the evaporation temperature, to allow the source material 312 to gradually evaporate at a predetermined evaporation rate.

[0049] The evaporation source 300 may further include a system controller 336 for controlling various aspects of the evaporation source and the evaporation device. The system controller 336 facilitates the control and automation of the evaporation source and the evaporation device and may include a central processing unit (CPU), memory, and support circuits (or I / O). Software instructions and data may be encoded and stored in the memory to guide the CPU. The system controller 336 may communicate with one or more components of the evaporation device via, for example, a system bus. A program (or computer instruction) may be read by the system controller 336, which determines which tasks may be performed on the substrate. In some aspects, the program is software that can be read by the system controller 336 and may include code for monitoring chamber conditions, including independent temperature control of one or more evaporation sources 300. Although only a single system controller 336 is shown, it should be understood that the aspects described herein may use multiple system controllers.

[0050] Figure 4 A schematic cross-sectional view of an evaporation device 400 according to an embodiment of the present disclosure is shown. Figure 5A A schematic diagram of an evaporation device 400 is shown, viewed along the axis of rotation of a rotatable drum 410. The evaporation device 400 may include an evaporation source 300 or several evaporation sources according to any embodiment described herein, for example, with Figure 3Related evaporation source 300.

[0051] The evaporation apparatus 400 includes a substrate support in the form of a rotatable drum 410 having a curved drum surface 411 to support the substrate 310 during the deposition process. The plurality of nozzles 321 of the evaporation source 300 are oriented toward the curved drum surface 411, and the evaporation apparatus 400 is configured to move the substrate 310 past the evaporation source 300 on the curved drum surface 411. In some embodiments, several evaporation sources 300, as described herein, can be arranged sequentially in a circumferential direction T around the rotatable drum 410 so that the substrate 310 can be coated by several evaporation sources 300 at a time. Different coating materials can be deposited on the substrate 310, or a thicker coating of the same coating material can be deposited on the substrate 310 by the evaporation source 300.

[0052] like Figure 4 and Figure 5A As shown, the evaporation source 300 includes an evaporation crucible 330 for evaporating material, a vapor distributor 320 with a plurality of nozzles 321 for directing the evaporated material toward a substrate 310 supported on a rotatable drum 410, and a vapor conduit 340 extending from the evaporation crucible 330 to the vapor distributor 320, which provides a fluid connection between the evaporation crucible 330 and the vapor distributor 320. At least one nozzle or all of the plurality of nozzles 321 may have their nozzle axes extending in or substantially parallel to the conduit length direction "A". Figure 4 As shown, the conduit length direction “A” may substantially correspond to the radial direction of the rotatable drum 410 .

[0053] In one or more embodiments, which may be combined with other embodiments described herein, the plurality of nozzles 321 may be arranged into a plurality of nozzle rows extending along a row direction "L" and adjacent to one another in a circumferential direction "T," wherein the row direction "L" substantially corresponds to the axial direction of the rotatable drum 410. Thus, the steam distributor 320 provides an area showerhead having a plurality of nozzles arranged in a two-dimensional array to reduce the heat load per unit area of the substrate 310 supported on the curved drum surface 411.

[0054] like Figure 5AAs shown, three, four or more evaporation sources 300A-300C described herein can be arranged sequentially in the circumferential direction "T" of the rotatable drum 410. Each evaporation source 300A-300C can define a coating window on the curved drum surface 411, and the angular range (a) covered by the window is 10° or greater and 45° or less. The conduit length direction "A" of adjacent evaporation sources 300 can respectively enclose an angle of 10° or greater and an angle not exceeding 45°. Therefore, the curved drum surface 411 of the rotatable drum 410 is very suitable for vapor deposition on flexible substrates, such as metal foils or plastic substrates, and can reduce the risk of substrate damage because the heat load per unit substrate area can be kept low while maintaining a high deposition rate.

[0055] In one or more embodiments, which can be combined with other embodiments described herein, the evaporation sources 300A-300C further include an edge exclusion shield 430 extending from the evaporation source 300 to the curved drum surface 411. Figure 4 The edge exclusion mask 430 may include an edge exclusion portion 431 for shielding areas on the substrate 310 that do not need to be coated, such as shielding side edge areas of the substrate 310 to keep them free of coating material. For example, the edge exclusion portion 431 may be designed to shield two opposing side edges of the substrate 310.

[0056] The edge exclusion portion 431 can extend along the curved drum surface 411 of the rotatable drum 410 in the circumferential direction "T", following the curvature of the curved drum surface 411. Therefore, the width of the gap "D" between the curved drum surface 411 and the edge exclusion portion 431 can be kept small (e.g., 2 mm or less) and substantially constant in the circumferential direction T, which can improve the accuracy of edge exclusion and deposit a sharp and well-defined edge of the coating layer on the substrate.

[0057] As used herein, the circumferential direction "T" is understood to refer to the circumferential direction of the rotatable drum 410, corresponding to the direction of movement of the curved drum surface 411 as the rotatable drum 410 rotates about its axis. The circumferential direction "T" corresponds to the direction of transport of the substrate 310 as it passes over the evaporation source 300 on the curved drum surface 411. In certain embodiments, the diameter of the rotatable drum 410 ranges from approximately 300 mm to approximately 1400 mm or greater. Reliably shielding the vapor 315 downstream of the plurality of nozzles 321 to confine the vapor 315 within the vapor propagation volume 432 and provide well-defined and sharp coating edges is particularly challenging when coating a flexible substrate moving on the curved drum surface 411, where the vapor propagation volume 432 and coating window may have complex shapes. The embodiments described herein enable reliable and accurate edge exclusion and material shielding in an evaporative deposition apparatus configured to coat a web-based substrate provided on the curved drum surface 411. Specifically, the edge exclusion shield 430 may partially surround a steam propagation volume 432 downstream of the plurality of nozzles 321 , confine the steam 315 in the steam propagation volume 432 , and provide accurate edge exclusion through the edge exclusion portion 431 .

[0058] In one or more embodiments, these embodiments can be combined with other embodiments described herein to provide a heating device for actively or passively heating the edge exclusion hood 430. For example, the edge exclusion hood 430 can be heated to a temperature above the condensation temperature of the evaporated material to reduce or prevent condensation of the material on the edge exclusion hood 430. This can reduce the frequency of cleaning operations and improve the quality of the coating edge. For example, during the vapor deposition process, the edge exclusion hood 430 can be heated to a temperature of approximately 500° C. or higher.

[0059] The edge exclusion cover 430 does not contact the rotatable drum 410 , so that a substrate supported on the rotatable drum 410 can pass through the evaporation source 300 and the edge exclusion cover 430 during the vapor deposition process.

[0060] The evaporation device 400 can be a roll-to-roll deposition system for coating a flexible substrate, such as a foil or a plastic substrate. The thickness of the substrate 310 to be coated can be 50 μm or less, in particular 20 μm or less, or even 6 μm or less. For example, a metal foil, a flexible metal-plated foil, a polymer substrate, or a flexible polymer substrate can be coated in the evaporation device 400. In some embodiments, the substrate 310 is a thin copper foil or a thin aluminum foil with a thickness of less than 30 μm, for example 6 μm or less. The substrate 310 can also be a thin metal foil (e.g., a copper foil) or a polymer substrate (e.g., a PET substrate) coated with graphite, silicon, silicon oxide, or any combination thereof, for example, with a thickness of 150 μm or less, in particular 100 μm or less, which can even be reduced to 50 μm or less. According to some embodiments, this roll can further contain graphite, silicon, silicon oxide, or any combination thereof. For example, lithium can pre-lithiate a layer containing graphite, silicon, silicon oxide, or any combination thereof.

[0061] In a roll-to-roll deposition system, the substrate 310 can be unwound from a storage roll while at least one or more material layers are deposited on the substrate 310, and the deposition is performed as the substrate 310 is guided along the curved drum surface 411 of a rotatable drum 410, and the deposited substrate can then be rolled up on a take-up roll and / or can be coated in a further deposition device.

[0062] The substrate 310 is held on the curved drum surface 411 using an electrostatic chuck device built into the rotatable drum 410. Depending on the type or material of the substrate, the electrostatic chuck device can be integrated in the rotatable drum 410 in different embodiments, such as Figure 5B 、 Figure 6 and Figure 7 ,or Figure 8 and Figure 9 The configuration shown in .

[0063] Figure 5BA cross-sectional end view of a rotatable drum 500 conveying a substrate 310 is shown. The rotatable drum 500 guides the substrate 310 with the assistance of a plurality of rollers 503. The rotatable drum 500 has a drum shaft 502 at its center. An electrode 504 at least partially surrounds the drum shaft 502. In some embodiments, the electrode 504 is a powered electrode that completely surrounds the drum shaft 502, referred to herein as a monopolar configuration. In some embodiments, the electrode 504 includes a first hemisphere 514A and a second hemisphere 514B. In some embodiments, a DC power of approximately -1300V to approximately -1200V is supplied to the electrode 504 from the power supply 501. The first hemisphere 514A is powered, while the second hemisphere 514B is grounded, referred to herein as a bipolar configuration. The first hemisphere 514A and the second hemisphere 514B can be electrically isolated using dielectric isolators 520A-B. In some embodiments, the electrode 504 is fixed and electrically connected to the curved surface 518 of the rotatable drum 500.

[0064] The electrode 504 is electrically connected to the curved surface 518 via a plurality of movable electrode spokes 506 extending from the electrode 504 to the curved surface 518. In certain embodiments, the spokes 506 extend through the body 512 of the rotatable drum 500. The spokes 506 are electrically isolated from the body 512 of the rotatable drum 500 by dielectric insulators 508. The spokes 506 are electrically connected to the electrode 504 at connection points 510, which can be engaged or disengaged depending on the desired attraction or release. The body 512 of the rotatable drum 500 is made of metal, such as stainless steel or a material containing copper. The body 512 of the rotatable drum 500 is water-cooled and includes a plurality of gas channels 516. These gas channels 516 form a heat sink for maintaining the substrate temperature at approximately 200°C or less, for example, from approximately 60°C to approximately 180°C, or from approximately 100°C to approximately 160°C, or from approximately 120°C to approximately 140°C. In certain embodiments, the substrate is copper and has a thickness of about 4 μm to about 6 μm. Without being limited by theory, it is believed that thin substrates are more sensitive to thermal expansion, which may lead to substrate defects. Polymer adhesives are commonly used for substrates used in battery anodes, and when exposed to high temperatures (e.g., hot lithium), the adhesives may melt, degrade, or lose their adhesive properties. It has been found that using the apparatus and methods provided herein to effectively maintain substrate temperature can improve production without affecting substrate performance.

[0065] The body 512 is surrounded by a dielectric portion 519, such as a dielectric coating, such as a spray coating. The dielectric portion 519 can be implemented in a variety of ways, depending on the characteristics of the substrate to be retained on the rotatable drum 500. In some embodiments, the dielectric portion 519 includes a patterned electrode structure. In some embodiments, the dielectric portion 519 includes diamond-like carbon, aluminum oxide, boron nitride, polyimide, or a combination thereof.

[0066] Figure 6A cross-sectional view of a dielectric portion 600 is shown, which may be used as Figure 5B The dielectric portion 519 in the dielectric portion 600 includes a base layer 602, such as a copper layer, a first protective layer 604A disposed on the base layer 602, a second protective layer 604B disposed on the first protective layer 604A, and a pattern electrode 700 (e.g., as shown in FIG. Figure 7 ), the electrode includes a plurality of mesa structures 606 formed on the second protective layer 604B. The third protective layer 604C is formed on the plurality of mesa structures 606, and the substrate 310 can be maintained on the third protective layer 604C. Each protective layer 604A, 604B, 604C can independently be an adhesive layer, such as one or more polyimide layers. In one or more embodiments, the first protective layer 604A can be or include a first polyimide layer, the second protective layer 604B can be or include a second polyimide layer, and the third protective layer 604C can be or include a third polyimide layer. In certain embodiments, the protective layers 604A-C can be or include aluminum oxide, and the patterned electrode 700, for example, the mesa structure 606 can be or include a material containing aluminum, such as aluminum or an aluminum alloy. In certain embodiments, the patterned electrode 700 covers the entire surface of the drumhead.

[0067] In some embodiments, the height "M" of the mesa structure 606 is about 100 μm to about 300 μm, for example, about 120 μm to about 200 μm. In some embodiments, the stacking height "H1" of the first protection layer 604A, the second protection layer 604B, the third protection layer 604C, and the mesa structure 606 may be about 100 μm to about 400 μm, for example, about 200 μm to about 250 μm. Figure 7 In some embodiments, channels 706 are formed between adjacent mesa structures 606. Figure 6 In some embodiments, the height "H3" of the channel 706 formed between adjacent mesa structures 606 is about 100 μm to about 300 μm. In some embodiments, the gap height "H2" between the substrate 310 and the surface 608 of the protective layer 604C is about 0.5 μm to 10 μm, for example, about 1 μm to about 8 μm, or about 2 μm to about 6 μm.

[0068] Figure 7A top view of dielectric portion 600 is shown. A plurality of mesa structures 606 can be arranged in rows 702, 704. Each mesa structure 606 in each row can be connected in series (e.g., connection 708) and connected to a power source 710 or ground. In some embodiments, each charged row 702 alternates with a grounded row 704. This alternating arrangement of charged and grounded electrode rows is referred to herein as a bipolar configuration and enables adsorption to substrates made of a variety of different materials, such as paper and plastics, such as PET. Alternatively, all rows 702, 704 can be charged, while the substrate is grounded foil, which is referred to herein as a monopolar configuration. The mesa structures 606 in each row are separated by channels 706, allowing gas to flow between the mesa structures 606. The gas can flow generally parallel to the surface 608 of dielectric portion 600 to form a gap, such as the gap defined by "H2," between the surface 608 and the back side of substrate 310. In some embodiments, the electrodes, instead of mesas 606, are elongated, continuous strips extending from one edge of the dielectric portion 600 to the opposite edge. Each electrode strip can be powered in a monopolar configuration or alternate between powered and grounded in a bipolar configuration. In some embodiments, argon gas is supplied through a gas nozzle parallel to the drum surface to maintain the gap. The nozzle has a diameter of about 200 μm to about 1000 μm, for example, about 300 μm to about 500 μm.

[0069] Figure 8 1 shows a cross-sectional end view of a dielectric portion 600 connected to a drum body according to some embodiments. The dielectric portion 600 may be as follows Figure 8 , is connected to the drum body 800. The rotatable drum body 800 may include multiple segments 802, such as one or more circumferential segments. The multiple segments 802 may include gas channels 810, such as cooling channels for cooling. In certain embodiments, the diameter of the drum is about 200 mm to about 700 mm, such as about 300 mm to about 600 mm, or about 400 mm to about 500 mm. In certain embodiments, the body 800 may include about 10 to about 40 segments, such as about 22 to about 32 segments. The arc angle 804 of a segment in the multiple segments 802 may be about 10 degrees to about 40 degrees, such as about 15 degrees to about 20 degrees, depending on the number of segments. In certain embodiments, the body 800 may include a gas nozzle 808 extending from an inner surface 814 of the body 800 to an outer surface 816 of the body 800. Figure 9 An interior view of the gas passage 810 and gas nozzle 808 of segment 802 is shown.

[0070] Figure 10 is a flow chart illustrating a method 1000 for coating a substrate according to embodiments described herein.

[0071] In operation 1002, a substrate, such as substrate 310, is conveyed onto a curved surface of a rotatable drum, such as curved surface 518 of rotatable drum 500. In certain embodiments, the substrate is secured to the curved surface using a low tension force, such as approximately 20 N / m or less, such as approximately 5 N / m to approximately 15 N / m, or approximately 10 N / m to approximately 12 N / m. This tension force creates a uniform gap between the substrate and the curved surface before the substrate is attached. The gap varies by approximately 75 μm or less. The rotatable drum includes one or more electrodes that allow the substrate to be electrostatically attached to at least a portion of the curved surface of the rotatable drum. After electrostatic attachment is applied, the gap variation is reduced to approximately 10 μm or less.

[0072] In operation 1004, a material is evaporated in an evaporation crucible. For example, a metal such as lithium is evaporated in an evaporation crucible, such as evaporation crucible 330. The temperature of the evaporation crucible can be heated to about 500° C. or higher, such as about 600° C. to about 1200° C., such as about 700° C. to about 1000° C.

[0073] In operation 1006, evaporated material is directed from the evaporation crucible toward the substrate. As the evaporated material is directed toward the substrate, the substrate is held on the curved surface of the rotatable drum, forming a gap between the substrate and the curved surface of the rotatable drum. A gas, for example a non-reactive gas such as argon, is supplied into the gap between the back surface of the substrate and the curved surface of the rotatable drum. In certain embodiments, the gap is approximately 0.5 μm to 10 μm, for example, approximately 1 μm to approximately 8 μm, for example, approximately 2 μm to approximately 6 μm. As the evaporated material is deposited onto the substrate, the substrate is continuously transported in the machine direction, extending from the inlet side to the outlet side of the rotatable drum. The substrate is attracted at the inlet side and released at the outlet side to release the substrate from the drum surface.

[0074] In some embodiments, the substrate is a flexible substrate supported on the curved surface of a rotatable drum during the deposition process. Specifically, the substrate can pass through a plurality of nozzles to deposit the material on the substrate on the curved surface of the rotatable drum.

[0075] The substrate may be a flexible film, particularly a flexible metal film, in particular a copper film or a copper-loaded film, for example, a film coated with copper on one or both sides. The substrate may have a thickness of 50 μm or less, particularly 20 μm or less, for example, approximately 8 μm. In certain embodiments, the substrate may be a thin copper film having a thickness of less than 20 μm.

[0076] According to certain embodiments, a battery anode can be fabricated in combination with other embodiments described herein, and the flexible substrate includes or consists of a polymer, copper, or a copper alloy. According to certain embodiments, the coil can also include graphite, silicon, silicon oxide, or any combination thereof. For example, lithium can pre-lithiate a layer including graphite, silicon, and / or silicon oxide.

[0077] Depositing metals (e.g., lithium) by evaporation onto flexible substrates, such as copper substrates, can be used to manufacture batteries, such as lithium batteries. For example, a lithium layer can be deposited onto a thin, flexible substrate to produce a battery anode. After assembling a stack of anode and cathode layers, optionally with an electrolyte and / or separator between them, the resulting layer arrangement can be rolled or otherwise stacked to produce a lithium battery.

[0078] The embodiments described above offer numerous advantages, including the ability to improve vapor deposition on flexible substrates. The rotatable drum can rotate during deposition to expose different areas of the substrate to the deposition environment while maintaining a uniform gap height across the web, which improves heat transfer across the substrate. Electrostatic adsorption resists "swelling" or "web slip" at high gap pressures and maximizes thermal conductivity, enabling web coating at low thermal budgets, such as below 80 degrees Celsius, to increase throughput. However, the present disclosure does not require that all advantageous features and advantages be incorporated into every embodiment of the present disclosure.

[0079] Reference is made to specific features (including process operations) of the present disclosure in the abstract, detailed description, claims, and drawings. It should be understood that the disclosure herein includes all possible combinations of these specific features. For example, a specific feature disclosed in the context of a particular aspect, embodiment, or example may also be used in combination with other specific aspects and embodiments of the present disclosure, to the extent possible, and will apply generally throughout the present disclosure.

[0080] The embodiments and all functional operations described in this specification can be implemented in digital electronic circuits, computer software, firmware, or hardware, including the structural methods disclosed in this specification and their structural equivalents, or a combination thereof. The embodiments described herein can be implemented as one or more non-transitory computer program products, i.e., one or more computer programs embodied in a machine-readable storage device, for execution or control of the operation of a data processing device, such as 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. These processes and logic flows can also be performed by, and devices can be implemented in, special-purpose logic circuits, for example, FPGAs (field programmable gate arrays) or ASICs (application-specific integrated circuits).

[0082] The term "data processing apparatus" encompasses all equipment, devices, and machines for processing data, including, for example, a programmable processor, a computer, or multiple processors or computers. In addition to hardware, the apparatus may also include program code that creates an environment for executing the computer program, such as program code forming processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of these. Processors suitable for executing a computer program include, for example, general-purpose and special-purpose microprocessors, and any one or more processors of any type of digital computer.

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

[0084] The term "comprising" and its grammatical equivalents are used herein to indicate that other components, ingredients, operations, etc. are optional. For example, an article that "comprising" (or "includes") components A, B, and C may consist of (i.e., contain only) components A, B, and C, or may contain not only components A, B, and C, but also one or more other components. Furthermore, whenever a combination, an element, or a group of elements is preceded by the transition phrase "comprising" or its grammatical equivalents, it is understood that the same combination or group of elements is also intended to include the meaning of the transition phrase "consisting essentially of," "consisting of," "selected from the group consisting of," or "is" preceding the listing of the combination, element, or group of elements, and vice versa.

[0085] Where reference is made herein to methods comprising two or more defined operations, these defined operations may be performed in any order or concurrently (unless the context excludes such possibility), and the method may include one or more additional operations performed before any defined operation, between two defined operations, or after all defined operations (unless the context excludes such possibility).

[0086] While the foregoing is directed to certain embodiments, other further embodiments may be devised without departing from the basic scope, which is determined by the following claims.

Claims

1. A rotatable drum for supporting a substrate, comprising: a curved drum surface for supporting the substrate and comprising a dielectric portion; as well as An electrode connected to a power source is electrically connected to the curved drum surface and can attract and release the substrate in one or more circumferential sections of the curved drum surface.

2. The rotatable drum of claim 1, wherein the dielectric portion comprises a material selected from the group consisting of diamond-like carbon, aluminum oxide, boron nitride, polyimide, and combinations thereof.

3. The rotatable drum of claim 1, wherein the electrode is a fixed electrode spaced radially inwardly of the curved drum surface and electrically connected to the curved drum surface via a plurality of movable electrode spokes.

4. The rotatable drum of claim 1, wherein the electrode comprises a first hemisphere that is grounded and a second hemisphere that is connected to the power source.

5. The rotatable drum of claim 1 , wherein each of the one or more circumferential segments includes at least one cooling channel and one or more gas channels extending from an inner surface of the circumferential segment to the curved drum surface.

6. The rotatable drum of claim 1 , wherein the dielectric portion of the curved drum surface comprises: a first polyimide layer; a pattern electrode disposed on the first polyimide layer; as well as A second polyimide layer is disposed on the pattern electrode. The rotatable drum according to claim 6 , wherein the pattern electrode comprises copper.

8. The rotatable drum of claim 6, wherein the pattern electrode comprises a plurality of mesas.

9. A rotatable drum according to claim 8, wherein the lands are polygonal in shape.

10. The rotatable drum of claim 8, wherein the lands are arranged in rows extending from one edge of the rotatable drum to an opposite edge of the rotatable drum.

11. The rotatable drum of claim 8, further comprising surface channels disposed between adjacent rows of the pattern electrodes, wherein the rows alternate between a first row being connected to a power source and a second row being connected to ground. 12 . The rotatable drum according to claim 1 , further comprising a heat sink, wherein the heat sink is disposed radially inside the curved drum surface and radially outside the electrode.

13. A vapor deposition device comprising: The rotatable drum according to claim 1; as well as An evaporation source is configured to deposit material onto a substrate disposed on the curved surface of the rotatable drum.

14. An electrode assembly for electrostatically adsorbing a substrate onto a rotatable drum, comprising: a first protective layer in contact with the rotatable drum; an electrode disposed on the first protective layer; as well as A second protective layer is disposed on the electrode, and the second protective layer includes a curved surface for supporting the substrate. 15 . The electrode assembly of claim 14 , wherein the first protective layer and the second protective layer comprise aluminum oxide, and the electrode comprises aluminum or an alloy of aluminum.

16. The electrode assembly of claim 14, wherein the electrodes are arranged in a plurality of rows extending generally parallel to one another and extending from an edge of the rotatable drum to an opposite edge of the rotatable drum.

17. A rotatable drum according to claim 16, wherein the rows alternate between a first row connected to a power source and a second row connected to ground, with channels provided between the rows.

18. A method of coating a substrate in a vacuum chamber, comprising: conveying a substrate onto a curved surface of a rotatable drum, wherein the substrate is electrostatically attached to at least a portion of the curved surface of the rotatable drum; evaporating material in an evaporation crucible; and The evaporated material is directed from the evaporation crucible toward the substrate.

19. The method of claim 18, wherein conveying the substrate further comprises holding the substrate on the curved surface of the rotatable drum with a gap formed between the substrate and the curved surface of the rotatable drum.

20. The method of claim 19, further comprising providing a gas to the gap between the back surface of the substrate and the curved surface of the rotatable drum.

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