System for powder coating with ultrasonic application

Abstract

A system for powder coating is provided. The system includes a powder deposition unit configured to deposit powder particles onto a web. The system includes at least one ultrasonic source configured to apply ultrasonic waves to at least a portion of the powder particles deposited on the web.

Description

Attorney Docket No. 137174.00101SYSTEM FOR POWDER COATING WITH ULTRASONIC APPLICATIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 699,573, filed on September 26, 2024. The entire content of the foregoing provisional application is incorporated herein by reference in its entirety.BACKGROUND

[0002] A variety of batteries are available in the industry for different uses. Lithium- ion (Li-ion) batteries have generally become the predominant type of battery used in portable consumer electronics and electric vehicles. Fabrication of Li-ion batteries involves numerous steps, each of which can affect the quality of the battery itself, as well as the cost involved in manufacturing the battery. A conventional manufacturing process generally includes formation of an electrode slurry having an active material, a conductive additive, and a binder, mixed in an organic solvent, and the electrode slurry is applied to a metal foil material. Once applied to the foil material, the solvent is dried out or evaporated while the active electrode mixture remains attached to the metal foil material surface. In some instances, the solvent may be toxic and can necessitate additional steps for handling / discarding that increase the overall cost of the manufacturing process. The cost of removing the solvent from the coated material on the metal foil therefore involves an additional step that also increases the overall cost of the manufacturing process.

[0003] An alternative manufacturing technique used in the industry is electrostatic deposition (ESD), which is a solvent-free manufacturing process for electrode coating for Li-ion batteries. (See, e.g., B. Ludwig et al., Solvent-Free Manufacturing of Electrodes for Lithium-ion Batteries, Sci. Rep. 6, Article No. 23150, doi: 10.1038 / srep23150 (2016); M. Wang et al., The Influence of Polyvinylidene Fluoride (PVDF) Binder Properties on LiNio.33Coo.33Mno.33O2 (NMC) Electrodes Made by a Dry-Powder-Coating Process, J. Electrochem. Soc., Vol. 166, No. 10, A2151 (2019); H. Abe et al., Electrostatic Spray Deposition for Fabrication of Li-ion Batteries, Transactions of JWRI, Vol. 44, No. 2 (2015); and U.S. Patent No. 10,547,044). Rather than relying on a solvent mixture, the ESD process uses a dry powder of the active electrode mixture which is applied to the metal foil material. By removing the solvent from the mixture and the drying step from the manufacturing process, the overall process is simplified and becomes more economical, resulting in a viable alternative for large-scale manufacturing. In particular, the solvent-1MEl\58063819.vlAttorney Docket No. 137174.00101 free electrode coating technology is an attractive alternative to traditional manufacturing since it can significantly reduce energy consumption in the manufacturing process and thus significantly reduces the manufacturing cost of batteries.

[0004] In a conventional continuous dry powder ESD coating system, a web (e.g., a grounded electrically conductive substrate) passes continuously through a coating chamber while the dry powder mixture is fluidized and pneumatically conveyed from a hopper to an electrostatic spray gun. The electrostatic spray gun electrostatically charges the powders using tribo-charging or corona charging, and sprays the charged powders onto the web where they are deposited.

[0005] Another conventional manufacturing process for coating of a web is referred to as “spreader roller coating”. A spreader roller coating system generally includes a reservoir that receives and dispenses powder particles onto a moving web. The web is passed through a pair of spreading rollers to spread and distribute the powder particles uniformly on the surface of the web to achieve a uniform coating on the web. The web is subsequently passed through a pair of calender rollers which compress and densify the powder particles. Such compression and densification causing the powder particles to adhere to each other and the web. Compression and densification performed by the calender rollers with or without heating promotes cohesion and adhesion of the powder particles to the web, and after such process, a dry electrode is produced. Such spreader roller coating technology is described in, e.g., International Patent Application No. PCT / US23 / 69175, which is incorporated herein by reference in its entirety.

[0006] In some instances, the ESD coating method and the spreading roller coating method can be used in conjunction where first an ESD coated layer is produced on the web and then is subsequently refined by a spreading roller (or vice versa), as is described in International Patent Application No. PCT / US24 / 48849, filed on September 27, 2024, which is incorporated herein by reference in its entirety.

[0007] In both ESD coating and spreader roller technology, uniformity of the powder coating is essential for achieving a high performance battery electrode. However, during the powder application and / or deposition process, agglomeration or clumping of powder particles may occur, resulting in a non-uniform coating of the substrate prior to further processing. Such agglomeration can also affect the fusion success of particles at the compaction and / or heating stages. In some instances, uneven coating of the powder2MEl\58063819.vlAttorney Docket No. 137174.00101 particles at initial stages of the process can result in improper compaction. If a high level of uniformity of the powder coating cannot be achieved, the resulting battery electrode may have operational deficiencies.SUMMARY

[0008] Embodiments of the present disclosure provide an exemplary system for powder coating including an ultrasonic application stage. The system incorporates application of ultrasonic vibration in one or more stages of the powder coating process. According to the various embodiments discussed herein, application of ultrasonic vibration may result in and impart various characteristics of a powder coated in the powder coating process. Application of ultrasonic vibration to the deposited dry powder layer on the substrate enables deagglomeration, resettling and / or leveling, compaction, and eventual fusing of loose powder on the moving substrate. In particular, the ultrasonic vibration can break up clumps or grouping of particles to ensure uniform distribution of powder particles can be achieved. The ultrasonic vibration can further induce settling of particles relative to each other to achieve a level coating on the substrate. The ultrasonic vibration further results in an increased resistance to layer separation during high-speed compaction / calendering due to improved cohesive and adhesive forces on the coating. An increased and optimized level of uniformity in the powder coating can therefore be achieved by application of the ultrasonic vibration to the powder particles at one or more stages of the coating process.

[0009] In accordance with embodiments of the present disclosure, an exemplary system for powder coating including an ultrasonic application stage is provided. The system includes a powder deposition unit configured to deposit powder particles onto a web. The system includes at least one ultrasonic source configured to apply ultrasonic waves to at least a portion of the powder particles deposited on the web.

[0010] Application of the ultrasonic waves to at least the portion of the powder particles deposited on the web results in at least one of (i) deagglomeration, (ii) resettling, (iii) compaction, or (iv) fusion of the powder particles (e.g., fusion among the powder particles, between the powder particles, and the surface of the web). In some embodiments, a distance of the at least one ultrasonic source relative to the powder particles can be adjustable and selected to achieve at least one of the (i) deagglomeration, (ii) resettling, (iii) compaction, or (iv) fusion of the powder particles. In some embodiments, an amplitude of the at least one ultrasonic source can be adjustable and selected to achieve at least one of3MEl\58063819.vlAttorney Docket No. 137174.00101 the (i) deagglomeration, (ii) resettling, (iii) compaction, or (iv) fusion of the powder particles.

[0011] The system can include a coating chamber through which the web moves from an upstream direction to a downstream direction. The powder deposition unit can be disposed within the coating chamber. The powder particles can include a mixture of an anode, a cathode, and a binder material.

[0012] In some embodiments, the at least one ultrasonic source can be a sonotrode disposed over a top surface of the web onto which the powder particles are deposited to apply the ultrasonic waves directly to at least the portion of the powder particles. In some embodiments, the at least one ultrasonic source can be a sonotrode disposed directly beneath and in contact with a bottom surface of the web to apply the ultrasonic waves to at least the portion of the powder particles through the web. In some embodiments, the at least one ultrasonic source can be disposed at a distance spaced from the powder particles to apply the ultrasonic waves directly to at least the portion of the powder particles in a spaced manner without physical contact between the at least one ultrasonic source and the powder particles.

[0013] In some embodiments, an amplitude of the ultrasonic waves applied by the at least one ultrasonic source can be varied based on a speed of the web. In some embodiments, a closed-loop feedback system including a controller and one or more sensors can be used to detect the speed of the web and adjust (in real-time or substantially real-time) the amplitude of the ultrasonic waves applied to the powder particles. In some embodiments, the controller can regulate both the amplitude of the ultrasonic waves and the speed of the web to achieve the desired effect on the powder particles. In some embodiments, the system can include a first tension support element disposed upstream of the at least one ultrasonic source and a second tension support element disposed downstream of the at least one ultrasonic source, with the first and second tension support elements configured to maintain a uniform tension of the web during passage through or near the at least one ultrasonic source.

[0014] The system can include a conditioning assembly disposed downstream of the powder deposition unit and configured to condition the powder particles deposited on the web. The at least one ultrasonic source can be disposed between the powder deposition unit and the conditioning assembly. The at least one ultrasonic source can be disposed4MEl\58063819.vlAttorney Docket No. 137174.00101 between components of the conditioning assembly with the ultrasonic waves applied to at least the portion of the powder particles as part of a conditioning operation.

[0015] The system can include a calendering assembly disposed downstream of the conditioning assembly. In some embodiments, the ultrasonic waves applied by the at least one ultrasonic source can prepare the powder particles for calendering in the calendering assembly via, e.g., densification, or the like. The at least one ultrasonic source can be disposed between the conditioning assembly and the calendering assembly. The at least one ultrasonic source can be disposed between components of the calendering assembly with the ultrasonic waves applied to at least the portion of the powder particles as part of a calendering operation. In some embodiments, the at least one ultrasonic source can be configured to apply the ultrasonic waves to the powder particles during passage of the web and the powder particles through the calendering assembly to reduce a mobility of the powder particles during a calendering process.

[0016] The system can include a sensor configured to detect a characteristic of the powder particles after application of the ultrasonic waves. The system can include a controller in communication with the sensor and configured to adjust operation of the at least one ultrasonic source based on signals from the sensor indicative of the detected characteristic of the powder particles, thereby forming a feedback control loop. In some embodiments, the controller can be used to adjust at least one of (i) a speed of the web, or (ii) an amplitude of the ultrasonic waves generated by the at least one ultrasonic source, based on signals from the sensor indicative of the detected characteristic of the powder particles. In some embodiments, the web can be a metallic foil including at least one of Al, Cu, TI, or a composite polymer film (such as polyethylene terephthalate (PET)) with metallized surfaces, or the like.

[0017] In accordance with embodiments of the present disclosure, an exemplary system for powder coating is provided. The system includes a powder deposition unit configured to deposit powder particles onto a moving web. The system includes a first ultrasonic source disposed over the moving web and configured to apply a first set of ultrasonic waves to at least a first portion of the powder particles deposited on the moving web. The system includes a second ultrasonic source disposed below the moving web and configured to apply a second set of ultrasonic waves through the moving web to at least a second portion of the powder particles deposited on the moving web.5MEl\58063819.vlAttorney Docket No. 137174.00101

[0018] In accordance with embodiments of the present disclosure, an exemplary method of powder coating is provided. The method includes depositing powder particles onto a web with a powder deposition unit. The method includes applying ultrasonic waves to at least a portion of the powder particles deposited on the web with at least one ultrasonic source.

[0019] In some embodiments, the method can include detecting a characteristic of the powder particles after application of the ultrasonic waves with a sensor. The method can include transmitting a signal from the sensor to a controller indicative of the detected characteristic. The method can include adjusting operation of the at least one ultrasonic source to change the detected characteristic.

[0020] Any combination and / or permutation of embodiments is envisioned. Other objects and features will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the present disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] To assist those of skill in the art in making and using the system for powder coating with ultrasonic application, reference is made to the accompanying figures, wherein:

[0022] FIG. 1 is a diagrammatic side view of an exemplary system for powder coating in accordance with embodiments of the present disclosure.

[0023] FIG. 2 is a diagrammatic side view of an exemplary system for powder coating with ultrasonic application in accordance with embodiments of the present disclosure, including an ultrasonic source disposed below a moving substrate.

[0024] FIG. 3 is a diagrammatic side view of an exemplary system for powder coating with ultrasonic application in accordance with embodiments of the present disclosure, including an ultrasonic source disposed above a moving substrate.

[0025] FIG. 4 is a table of adjustable parameters for an ultrasonic source of an exemplary system for powder coating with ultrasonic application.6MEl\58063819.vlAttorney Docket No. 137174.00101

[0026] FIG. 5 is a diagrammatic side view of an exemplary system for powder coating with ultrasonic application in accordance with embodiments of the present disclosure, including an ultrasonic source disposed below a moving substrate.

[0027] FIG. 6 is a graphical representation of a function achieved by ultrasonic vibrations for a static web based on exposure time and amplitude, including deagglomeration, resettling, fusing, and compaction as compared to no ultrasonic vibration application.DETAILED DESCRIPTION

[0028] An exemplary system for powder coating is provided. The system includes one or more ultrasonic sources positioned above and / or below the moving substrate, and configured to apply ultrasonic vibration to the powder particles coated onto the substrate. The system allows for high-speed processing of dry powder coating for battery electrodes, while ensuring a uniform distribution of the powder coating. Operational parameters of the ultrasonic source(s) can be controlled via a processor / controller in communication with the ultrasonic source(s). Such operational parameters can include the amplitude of the ultrasonic source(s), and the distance of the ultrasonic source(s) relative to the powder particles. In some embodiments, the system can include a feedback control loop including one or more sensors configured to detect the uniformity of powder particles on the substrate, and in communication with the controller. Based on the received signals from the sensors, the controller can regulate operation of the ultrasonic source(s) to achieve an optimized uniformity of the powder coating.

[0029] The dry powder coating applied to the web can be sensitive to disas sociation / separation during high-speed calendering (e.g., compression or compaction) steps due to the lack of cohesive forces between neighboring loose particles and adhesive forces to the web (i.e., the current collector). Agglomerates present in the deposited powder layer can create thickness variation in the calender nip leading into various defects in the calendered electrode. The exemplary system applies controlled ultrasonic vibrational energy that induces in-situ particle interactions in the deposited loose powder, resulting in deagglomeration, resettling, compaction and / or fusing of the powder.

[0030] Materials used for the web may be selected for a variety of reasons, including, but not limited to, a range or minimum amount of electrical conductivity, an ability to form the material in a thin sheet (e.g., in the range between about 5 and 20 microns inclusive, for7MEl\58063819.vlAttorney Docket No. 137174.00101 example), a density of the material, an electrochemical compatibility of the material with the active material, the voltage range over which the active material must operate, cost, or combinations thereof, for example. According to some embodiments, the web material may include a metal (such as copper, an alloy of copper, aluminum, an alloy of aluminum, titanium, an alloy of titanium, or the like), a conductive polymer (such as poly (pyrrole), poly(acetylene), poly(vinylene), poly (thiophene), poly (aniline), poly(phenylene sulfide), or the like), a composite of a polymer (conductive or not), and / or a metal (where a non- conductive polymer may include at least one of an olefinic polymer, a poly (propylene), a poly (ethylene), a poly(styrene), a poly (aery lie), a fluorinated polymer (such as a poly(vinylidene fluoride), or a poly(tetrafluoroethylene), for example), a thermoset polymer, or a thermoplastic polymer, for example. According to some embodiments, a web may also include a laminate structure include a metal and a polymer, for example.

[0031] In particular, by regulating operational parameters of the ultrasonic source in the vicinity of the deposited dry powder layer on the substrate, the system enables deagglomeration, resettling / levelling, compaction and eventual fusing of loose powder on a moving web / substrate. Each of these functions in combination assist in realizing a highspeed processing of dry electrode manufacturing on a roll-to-roll system. By tuning the amplitude of an ultrasonic frequency (e.g., a fixed frequency) and the position of application of the ultrasonic waves near the loose powder coating, the advantageous effects on coating can be achieved individually or in a series of combinations. For example, the advantageous effects can be achieved at a single stage of ultrasonic application, or two of more ultrasonic application stages can be used to independently achieve one or more of the advantageous effects.

[0032] FIG. 1 is a diagrammatic view of an exemplary system 100 for powder coating for purposes of battery electrode fabrication (hereinafter “system 100”). The system 100 can be used to manufacture a coated substrate usable in, e.g., Ei-ion batteries, solid state batteries, or the like. The system 100 can be incorporated into a containment enclosure (e.g., a containment chamber, a coating chamber, or the like) for deposition of the powder coating onto a substrate or web 102, e.g., a continuously moving substrate or web 102. It should be understood that the enclosure or coating chamber includes a housing / structure positioned at least partially over the components illustrated in FIG. 1. The web 102 includes a top surface 104 configured to be coated, and an opposing bottom surface. In some embodiments, both surfaces of the web 104 can be coated. The powder coating8MEl\58063819.vlAttorney Docket No. 137174.00101 includes at least a cathode material or an anode material, e.g., for rechargeable lithium batteries, or the like. In some embodiments, a binder material can be included in the powder coating mixture.

[0033] At a starting point or upstream side, the system 100 includes a roller or spool 106 from which an uncoated web 102 is fed through the coating chamber. The spool 106 can maintain tension on the web 102 as it passes through the system 100 in combination with one or more rollers (omitted for clarity). The web 102 travels in a web direction 108 as it leaves the spool 106, and passes through or under a powder deposition unit 110. The deposition unit 110 can be any type of dry powder coating assembly known in the industry, such as ESD coating, spreader roller coating, or the like. For example, the deposition unit 110 can include a reservoir that receives a mixture of the powder particles for dispersion onto the web 102.

[0034] In some embodiments, the deposition unit 110 can include one or more powder dispersion systems, e.g., nozzles, rollers, dispensing tubes, mechanical feeders, electrostatic powder feeders, dispersion based on gravimetric or volumetric meter basis, vibratory and / or acoustic dispersion systems, or the like, and any one or combination of the following charging mechanisms, e.g., corona discharge (positive or negative), tribocharging, direct conduction charging, induction charging, dielectric barrier discharges, other non-thermal plasmas, or the like. In some embodiments, deposition unit 110 can include one or more features of those disclosed in International Patent Application No. PCT / US23 / 26276, filed on June 27, 2023; International Patent Application No. PCT / US23 / 82635, filed on December 6, 2023; and International Patent Application No. PCT / US24 / 18424, filed on March 4, 2024, each of which is incorporated herein by reference. In some embodiments, the deposition unit 110 can include one or more scattering rollers, one or more spreader rollers, and one or more calendering rollers.

[0035] Downstream of the deposition unit 110, the system 100 includes a conditioning assembly 112 with one or more pairs of rollers (e.g., rollers 114, 116, 118, 120, 122, 124) disposed above and below the web 102. The conditioning assembly 112 can alter the powder particles deposited onto the web 102 by, e.g., spreading, smoothening, compaction, combinations thereof, or the like. The conditioning assembly 112 ensures uniformity in the powder coating layer on the web 102.

[0036] After the powder particles have been conditioned, the web 102 moves further9MEl\58063819.vlAttorney Docket No. 137174.00101 downstream to a calendering assembly 126 in which compaction of the powder particles onto the top surface 104 of the web 102 is performed. Although only a single pair of calendering rollers 128, 130 is shown in FIG. 1, it should be understood that one or more pairs of calendering rollers could be used for compaction of the powder particle coating. In some embodiments, heat can be applied before, during and / or after the compaction steps.

[0037] In some embodiments, the compressive force applied by the calendering assembly 126 to form the coating layer can be about, e.g., 10-4000 N / mm inclusive, 10- 3900 N / mm inclusive, 10-3800 N / mm inclusive, 10-3700 N / mm inclusive, 10-3600 N / mm inclusive, 10-3500 N / mm inclusive, 10-3400 N / mm inclusive, 10-3300 N / mm inclusive, 10-3200 N / mm inclusive, 10-3100 N / mm inclusive, 10-3000 N / mm inclusive, 10-2900N / mm inclusive, 10-2800 N / mm inclusive, 10-2700 N / mm inclusive, 10-2600 N / mm inclusive, 10-2500 N / mm inclusive, 10-2400 N / mm inclusive, 10-2300 N / mm inclusive, 10-2200 N / mm inclusive, 10-2100 N / mm inclusive, 10-2000 N / mm inclusive, 10-1900 N / mm inclusive, 10-1800 N / mm inclusive, 10-1700 N / mm inclusive, 10-1600 N / mm inclusive, 10-1500 N / mm inclusive, 10-1400 N / mm inclusive, 10-1300 N / mm inclusive, 10-1200 N / mm inclusive, 10-1100 N / mm inclusive, 10-1000 N / mm inclusive, 10-900 N / mm inclusive, 10-800 N / mm inclusive, 10-700 N / mm inclusive, 10-600 N / mm inclusive, 10-500 N / mm inclusive, 10-400 N / mm inclusive, 10-300 N / mm inclusive, 10-200 N / mm inclusive, 10-100 N / mm inclusive, 10-50 N / mm inclusive, 10-20 N / mm inclusive, 20-4000 N / mm inclusive, 30-4000 N / mm inclusive, 40-4000 N / mm inclusive, 50-4000 N / mm inclusive, 100-4000 N / mm inclusive, 200-4000 N / mm inclusive, 300-4000 N / mm inclusive, 400-4000 N / mm inclusive, 500-4000 N / mm inclusive, 600-4000 N / mm inclusive, 700-4000 N / mm inclusive, 800-4000 N / mm inclusive, 900-4000 N / mm inclusive, 1000-4000 N / mm inclusive, 1100-4000 N / mm inclusive, 1200-4000 N / mm inclusive, 1300-4000 N / mm inclusive, 1400-4000 N / mm inclusive, 1500-4000 N / mm inclusive, 1600-4000 N / mm inclusive, 1700-4000 N / mm inclusive, 1800-4000 N / mm inclusive, 1900-4000 N / mm inclusive, 2000-4000 N / mm inclusive, 2100-4000 N / mm inclusive, 2200-4000 N / mm inclusive, 2300-4000 N / mm inclusive, 2400-4000 N / mm inclusive, 2500-4000 N / mm inclusive, 2600-4000 N / mm inclusive, 2700-4000 N / mm inclusive, 2800-4000 N / mm inclusive, 2900-4000 N / mm inclusive, 3000-4000 N / mm inclusive, 3100-4000 N / mm inclusive, 3200-4000 N / mm inclusive, 3300-4000 N / mm inclusive, 3400-4000 N / mm inclusive, 3500-4000 N / mm inclusive, 3600-4000 N / mm inclusive, 3700-4000 N / mm inclusive, 3800-4000 N / mm inclusive, 3900-4000 N / mm10MEl\58063819.vlAttorney Docket No. 137174.00101 inclusive, 20-1500 N / mm inclusive, 20-1000 N / mm inclusive, 20-500 N / mm inclusive, 20- 300 N / mm inclusive, 1000-3000 N / mm inclusive, 1500-2500 N / mm inclusive, 10 N / mm, 20 N / mm, 30 N / mm, 40 N / mm, 50 N / mm, 60 N / mm, 70 N / mm, 80 N / mm, 90 N / mm, 100 N / mm, 200 N / mm, 300 N / mm, 400 N / mm, 500 N / mm, 600 N / mm, 700 N / mm, 800 N / mm, 900 N / mm, 1000 N / mm, 1100 N / mm, 1200 N / mm, 1300 N / mm, 1400 N / mm, 1500 N / mm, 1600 N / mm, 1700 N / mm, 1800 N / mm, 1900 N / mm, 2000 N / mm, 2100 N / mm, 2200 N / mm, 2300 N / mm, 2400 N / mm, 2500 N / mm, 2600 N / mm, 2700 N / mm, 2800 N / mm, 2900 N / mm, 3000 N / mm, 3100 N / mm, 3200 N / mm, 3300 N / mm, 3400 N / mm, 3500 N / mm, 3600 N / mm, 3700 N / mm, 3800 N / mm, 3900 N / mm, 4000 N / mm, or the like, depending on the desired thickness, the type of powder particles used, or the like.

[0038] After compression by the calendering unit 126, the web 102 can be fed to a distal end of the system 100 (e.g., the downstream end) at which the web 102 is collected at a roller and / or spool 132. As will be discussed in greater detail below, the system 100 can incorporate one or more ultrasonic sources to apply ultrasonic vibration to the powder particles on the web 102. Such ultrasonic wave application to the powder particles assists with deagglomeration and settling / leveling of the powder particles, ensuring uniformity in the power particle layer. The ultrasonic wave application can also assist with improved compaction and fusion of the particles relative to each other, thereby optimizing the resulting battery electrode structure and functionality.

[0039] FIG. 2 is a diagrammatic view of an exemplary system 100 including an ultrasonic source 140 disposed below the web 102, and FIG. 3 is a diagrammatic view of an exemplary system 100 including an ultrasonic source 142 disposed above the web 102. In some embodiments, the system 100 can include an ultrasonic source 140, 142 both below and above the web 102, depending on the desired effect on the powder particles 144. In some embodiments, the system 100 can include ultrasonic sources 140, 142 at one or more stages of the conditioning assembly 112 and / or at one or more stages of the calendering assembly 126, and the ultrasonic sources 140, 142 can be selectively turned on and off depending on the desired end result of the powder coating and / or the electrode. In some embodiments, the ultrasonic sources 140, 142 can be positioned after the respective conditioning assembly 112 and / or the calendering assembly 126.

[0040] In some embodiments, the system 100 can include a feedback loop formed by one or more sensors 146 and a processor or controller 148 in communication with the sensors 146 and the ultrasonic sources 140, 142. The sensors 146 can be positioned over11MEl\58063819.vlAttorney Docket No. 137174.00101 the web 102 and are configured to detect one or more characteristics of the powder coating on the web 102 surface, e.g., uniformity, agglomeration, unevenness, compaction between particles, loose particles, combinations thereof, or the like. Based on the detected characteristics, signals from the sensors 146 can be transmitted to the controller 148 which, in turn, regulates on / off operation of the ultrasonic sources 140, 142, or regulates a respective positioning system 150, 152 for the ultrasonic source 140, 142 to reposition the ultrasonic sources 140, 142 relative to the web 102 and the powder particles 144. Such repositioning, as discussed herein, can affect the resulting function (or degree of function) from the ultrasonic wave application for purposes of deagglomeration, resettling / leveling, compaction and fusing. In some embodiments, one ultrasonic source 140, 142 can be used to achieve one of the desired functions, i.e., deagglomeration, resettling / leveling, compaction, or fusing. In some embodiments, one ultrasonic source 140, 142 can be used to achieve two or more functions.

[0041] In some embodiments, the positioning system 150, 152 can include, e.g., tracks 154, 156 and a support 158 coupled to the ultrasonic source 140, 142, or the like, such that the ultrasonic source 140, 142 can be moved along and perpendicular to the web direction 108. Although tracks 154, 156 and a support 158 are illustrated, it should be understood that any controllable positioning system can be used. The positioning systems 150, 152 can be used to adjust the distance 160 of the ultrasonic source 140 relative to the powder particles 144, and to adjust the distance and / or height 162 of the ultrasonic source 142 relative to the powder particles 144. The feedback control loop therefore allows for realtime adjustability of the system 100 operation to optimize the resulting uniformity in the powder particle layer.

[0042] In some embodiments, the ultrasonic source 140, 142 can be in the form of a sonotrode. A sonotrode is a tool typically used for ultrasonic machining and welding that creates and applies ultrasonic vibrational energy to a solid, liquid or gas. The sonotrode “horn” or probe can be of a specific geometry (including and not limited to rectangular or square block with sharp edges, rectangular or square block with profiled or rounded edges, circular roller, or the like) depending on the material and application types. For example, the ultrasonic source 140 can define a substantially rectangular configuration extending along some or the entire width of the web 102. As another example, the ultrasonic source 142 can define a “horn” or endpoint with rounded edges 164 (e.g., gradual transition edges). In some embodiments, the ultrasonic source 140, 142 can be configured to apply ultrasonic12MEl\58063819.vlAttorney Docket No. 137174.00101 waves to a specific, predefined area at which the waves are directed, with the area having a diameter less than the width of the web 102 (as measured perpendicular to the web direction 108). In some embodiments, the ultrasonic source 140, 142 can be configured to apply ultrasonic waves across the entire width of the web 102. In some embodiments, the ultrasonic waves are applied across the entire width of the web 102 with a predefined strip of the web 102 receiving the waves, e.g., with a predetermined limit to the length or depth of the wave application as measured along the web 102 direction).

[0043] The ultrasonic vibrational energy can be applied onto the loose powder (or partially compacted powder) using one or both of the “top-down” configuration (FIG. 3) or the “bottom-up” configuration (FIGS. 2 and 3). In the “top-down” configuration, the sonotrode is positioned above the deposited powder layer. In the “bottom-up” configuration, the sonotrode is positioned directly underneath the web 102. As shown in FIGS. 2 and 3, for a “bottom-up” configuration, the sonotrode (i.e., the ultrasonic source 140) producing ultrasonic vibrations is carefully placed underneath the moving web 102, ensuring contact with the tensioned web 102, which is coated with dry loose powder particles 144 thereon. In particular, the ultrasonic source 140 is positioned to be in direct and constant contact with the bottom surface of the web 102, such that ultrasonic waves can pass into the powder particles 144 through the web 102 (e.g., perpendicularly through the web 102). Although positioning the ultrasonic source 140 offset from the web 102 is envisioned, for optimal operation, the ultrasonic source 140 should remain in contact with the web 102. In some embodiments, only the ultrasonic source 140 can be used, only the ultrasonic source 142 can be used, or both ultrasonic sources 140, 142 can be used. In some embodiments, each of the ultrasonic sources 140, 142 can be used to achieve one or more of the four functions discussed herein. In some embodiments, the ultrasonic source 140 can be used for fusion purposes, and the ultrasonic source 142 can be used for the remaining functions discussed herein. In some embodiments, the ultrasonic sources 140, 142 can be used to achieve the four functions together.

[0044] In some embodiments, ultrasonic vibration normal to the web 102 can be applied to the coated layer (e.g., the powder particles 144) for successful processing of the mentioned functions, such as deagglomeration, resettling, and / or fusing. For a static web 102, when the ultrasonic horn (i.e., the ultrasonic source 140) is brought into contact with the web 102 from below (normal to the web 102), particle motion starts from the edges of the coated layer. Depending on the amplitude of the ultrasonic vibrations provided by the13MEl\58063819.vlAttorney Docket No. 137174.00101 ultrasonic source 140, and the exposure time and the position of the ultrasonic source 140 with respect to the coating layer, powder resettling and powder fusing to the web 102 can be observed.

[0045] FIG. 5 illustrates an embodiment of an exemplary system 200 for powder coating with ultrasonic application. The system 200 can be substantially similar to the system 100, except for the distinctions noted herein. Therefore, the same reference numbers are used to refer to the same structures. The system 200 illustrates a moving web 102 for a roll-to-roll process of manufacturing. As shown in FIG. 5, the powder deposition unit 110 deposits a powder coating layer 202 on the web 102, and the coated web 102 is subsequently moved in direction 108 towards a conditioning assembly 112. Prior to the conditioning assembly 112, the system 200 includes an ultrasonic source 204 (e.g., a sonotrode) disposed below the web 102. In particular, the ultrasonic source 204 is positioned adjacent to a surface of the web 102 opposing the coated top surface 104. The ultrasonic source 204 can define a wrap to ensure good contact with the tensioned web 102, and is movable along a direction 208 perpendicular to the direction 108. As used herein, the term “wrap” refers to the degree to which the web 102 makes contact with the surface (e.g., the top surface) of the ultrasonic source 204. In some embodiments, the wrap for the ultrasonic source 204 can be about, e.g., 0-10 degrees, inclusive.

[0046] Due to the speed of the moving web 102, the exposure time with the ultrasonic vibration from the ultrasonic source 204 is limited and can be tuned to achieve a resettling and / or fusing function of the process by changing the amplitude of the sonotrode. In some embodiments, the shape of the ultrasonic source 204 can be cylindrical for linear vibrational direction. The ultrasonic source 204 can be placed normal to the web 102 (perpendicular relative to the bottom surface) to allow the vibration direction to act normal to the coated material from below the web 102, i.e., along direction 208.

[0047] For a moving web 102, the web 102 speed typically has an impact on the ultrasonic vibration process parameters. For slower web 102 speeds, due to relatively longer exposure time of the ultrasonic vibration, the amplitude can be tuned to lower values with the help of a controller 210. For faster web 102 speeds, the ultrasonic vibration exposure time is relatively shorter and hence the amplitude of the ultrasonic vibration can be tuned up with the controller 210 to allow for the minimum exposure time needed. In some embodiments, “lower values” can refer to a web speed of about, e.g., 10 m / min, and an amplitude for the sonotrode of about, e.g., 1.8 um (0 to peak, sinusoidal wave). In some14MEl\58063819.vlAttorney Docket No. 137174.00101 embodiments, “higher values” can refer to a web speed of about, e.g., 20 m / min, and an amplitude for the sonotrode of about, e.g., 3 um (0 to peak, sinusoidal wave). In some embodiments, once the working amplitude range for a certain web speed is achieved, the amplitude of the sonotrode can be tuned with gradual increments to match the operability for faster web speeds. In some embodiments, the ultrasonic amplitude can be about, e.g., 0-10 um inclusive, for web speeds up to 20 m / min.

[0048] In some embodiments, the controller 210 can be in communication with the ultrasonic source 204 and with a sensor detecting the speed of the web 102, such that the controller 210 can automatically and independently regulate the amplitude of the ultrasonic vibration generated by the ultrasonic source 204 based on the web 102 speed. To successfully incorporate the ultrasonic source 204 in the process, the web 102 tensioning is an important factor as it ensures uniform contact with the sonotrode. In some embodiments, the system 200 can include idler rollers 212, 214 upstream and downstream of the ultrasonic source 204 to ensure the desired web tensioning can be achieved. In some embodiments, the web tension can be about, e.g., 40-100 N inclusive, or the like, to ensure sufficient contact between the web and the sonotrode is maintained. In some embodiments, the web tension can be about, e.g., 10-200 N inclusive, 10-180 N inclusive, 10-160 N inclusive, 10-140 N inclusive, 10-120 N inclusive, 10-100 N inclusive, 10-80 N inclusive, 10-60 N inclusive, 10-40 N inclusive, 10-20 N inclusive, 20-200 N inclusive, 40-200 N inclusive, 60-200 N inclusive, 80-200 N inclusive, 100-200 N inclusive, 120-200 N inclusive, 140-200 N inclusive, 160-200 N inclusive, 180-200 N inclusive, 40-160 N inclusive, 60-140 N inclusive, 80-120 N inclusive, or the like, to ensure sufficient contact between the web and the sonotrode is maintained.

[0049] According to some embodiments, an ultrasonic source disposed over the web 102 may be configured to contact a free surface of the powder coating layer 202 on first surface 104 of the web 102, with an opposing surface of the web 102 contacting a backing object. As used herein, “free surface” refers to the surface of the coating not in contact with the web 102. For example, an ultrasonic source 142 (see FIG. 3) disposed over the web 102 can be used to contact the free surface of the coating layer 202. In such embodiments, rather than another ultrasonic source 140, the source 140 can represent the backing object disposed on the opposing side of the web 102. When an ultrasonic source contacts a free surface of the battery electrode powder layer, the backing object can provide a mechanical ground for the web 102, such that powder moves relative to the web 10215MEl\58063819.vlAttorney Docket No. 137174.00101 surface. Motion of the battery electrode powder along the web 102 surface may induce interactions including, e.g., deagglomeration, resettling, compaction, and / or fusing of the powder particles. In some embodiments, the backing object can be, e.g., an idler roller, a driven roller, a circular section, a plane, a sharp corner of a parallelepiped, a bullnose comer of a parallelepiped, a chamfered edge of a parallelepiped, a radiused edge chamfered edge of a parallelepiped, or another object.

[0050] According to some embodiments, the opposing surface of the web 102 (i.e., opposing the coated top surface 104) may be a bare surface (such as a surface of aluminum, copper, or other suitable alloy or material for a current collector), a surface at least partially coated with a primer layer (which may include a mixture of binder components, conductive additives, or the like), and / or a surface at least partially coated with battery electrode powder in a state of preparation sufficient to enable handling on the bottom surface of a conveying web (as may be achieved, for example, by conditioning, pre-compression, compression, ultrasonic treatment, or combinations thereof). In some embodiments, a backing object may be driven to carry, drive, convey, or otherwise move in substantially the same direction of the web 102 at positions of contact between the backing object and the web 102.

[0051] With reference again to FIGS. 2-3, the distance 160, 162 of the powder coating layer from the sonotrode edge and the amplitude (referred to as parameter “a”) of the ultrasonic vibration are two critical parameters controlled by the system 100 to dictate the degree of perturbation into the loose powder particles 144. In some embodiments, for the bottom up configuration with a stationary web 102, the distance 160 can be set to a value discussed herein. In some embodiments, for a moving web 102, the distance 160 can be zero with ultrasonic waves applied through the web 102 and to the powder particles passing directly (or substantially directly) above the ultrasonic source 140. In such embodiment, the ultrasonic waves can be directed substantially perpendicularly relative to the web 102. Such control results in selective deagglomeration (powder becomes finer), resettling and levelling due to increased particle mobility ranging from micro to mesoscale, increased compaction (particle density), and increased resistance to layer separation during highspeed calendering due to improved cohesive and adhesive forces in the coating. In some embodiments, the ultrasonic source 140, 142 can be used before the conditioning assembly 112, or between elements / stages of the conditioning assembly 112, to ensure uniformity in the powder particle 144 layer before calendering. In some embodiments, the ultrasonic16MEl\58063819.vlAttorney Docket No. 137174.00101 source 140, 142 can be used before, during and / or after the calendering assembly 126 to assist with compaction and fusion.

[0052] Ultrasonic vibrations from the ultrasonic sources discussed herein can be used to excite the powder particles in the coated material with mechanical vibrations which initiate particle motion (e.g., re-arrangement and / or resettling). The binder material present in the coated layer may be at least partially fused due to the mechanical energy imparted by ultrasonic vibration onto the powder particles. FIG. 6 illustrates the different functions achieved by ultrasonic vibrations based on the amplitude vs. exposure time for a static web 102. With shorter amplitude and lesser exposure time, the resettling function can be achieved. Deagglomeration can be achieved with higher amplitude with shorter exposure time. With an increase in exposure time, the compaction function can be achieved for lower amplitudes and lastly, fusing can be achieved with both high amplitude and high exposure time. It is understood that FIG. 6 provides a generalized representation for achieving the noted functionalities, and the amount of powder particles (e.g., the thickness of the powder particle coating on the web 102) may affect the exposure time needed to achieve the desired functionality.

[0053] For a moving web 102, a combination of the functions can be achieved by tuning the ultrasonic vibrations generated from below the web 102 and / or from above the coating layer 202. In some embodiment (see, e.g., FIG. 5), with an ultrasonic horn positioned below the web 102, a 2 um amplitude and 35 kHz ultrasonic vibration can enable a combination of particle deagglomeration, resettling and fusing. The coating area with and without ultrasonic activation can be observed clearly for the deagglomeration and resettling functionalities. The fusing function can be realized by vacuuming off the powder from the layer 202 on the web 102 and observing the residual layer (e.g., with loose powder particles being removed during vacuuming).

[0054] In some embodiments, the properties of the binder in the powder particle coating layer 202 can contribute to achieving the desired functionalities through ultrasonic vibration application. For example, in some embodiments, the amplitude and exposure time requirement of the ultrasonic vibrations may be dependent on the crystallinity and / or morphological characteristics of the binder material. For example, lower amplitude (e.g., about 30 micron, or the like) may be used for amorphous materials and relatively higher amplitude (e.g., about 60 micron, or the like) may be used for semi-crystalline materials. However, it should be understood that the amplitude can be adjusted as needed depending17MEl\58063819.vlAttorney Docket No. 137174.00101 on the polymer state (e.g., amorphous, crystallinity, or the like) and the resolution of sensitivity of the mixed powder system. As another example, the PVDF binder used in the battery electrode material is semi-crystalline in nature and relatively higher amplitude (e.g., about 1-10 um, or the like) may be used to fuse the material. Higher crystallinity content in the binder material generally indicates higher melt temperature, which may necessitate longer exposure or higher amplitude of the ultrasonic vibrations.

[0055] According to some embodiments, an amplitude of ultrasonic excitation may be, e.g., less than about 2 micrometers, between about 2 and about 5 micrometers (inclusive), between about 5 and about 10 micrometers (inclusive), between about 10 and about 25 micrometers (inclusive), between about 25 and about 50 micrometers (inclusive), greater than about 50 micrometers, or the like.

[0056] Achieving different degrees of the four functions individually and their combinations can be realized by fine tuning the two parameters of distance 160, 162 and amplitude, as illustrated in the Table of FIG. 4. In particular, the position or spacing of the sonotrode relative to the web coating can be fine-tuned to achieve different degrees of the four functions. In some embodiments, the distance 160, 162 can be about, e.g., 0-100 mm inclusive, 0-80 mm inclusive, 0-60 mm inclusive, 0-40 mm inclusive, 0-20 mm inclusive, 20-100 mm inclusive, 40-100 mm inclusive, 60-100 mm inclusive, 80-100 mm inclusive, 20-80 mm inclusive, 40-60 mm inclusive, 0 mm, 20 mm, 40 mm, 60 mm, 80 mm, 100 mm, or the like. In some embodiments, the distance 162 can be about, e.g., 0-500 um inclusive, 0-450 um inclusive, 0-400 um inclusive, 0-350 um inclusive, 0-300 um inclusive, 0-250 um inclusive, 0-200 um inclusive, 0-150 um inclusive, 0-100 um inclusive, 0-50 um inclusive, 50-500 um inclusive, 100-500 um inclusive, 150-500 um inclusive, 200-500 um inclusive, 250-500 um inclusive, 300-500 um inclusive, 350-500 um inclusive, 400-500 um inclusive, 450-500 um inclusive, 100-400 um inclusive, 200-300 um inclusive, 0 um, 50 um, 100 um, 150 um, 200 um, 250 um, 300 um, 350 um, 400 um, 450 um, 500 um, or the like. In some embodiments, for a moving web 102, the distance 160 can be substantially zero um.

[0057] In some embodiments, the amplitude for the ultrasonic sources 140, 142 can be about, e.g., 1-10 um inclusive, 1-9 um inclusive, 1-8 um inclusive, 1-7 um inclusive, 1-6 um inclusive, 1-5 um inclusive, 1-4 um inclusive, 1-3 um inclusive, 1-2 um inclusive, 2-10 um inclusive, 3-10 um inclusive, 4-10 um inclusive, 5-10 um inclusive, 6-10 um inclusive, 7-10 um inclusive, 8-10 um inclusive, 9-10 um inclusive, 2-8 um inclusive, 4-6 um18MEl\58063819.vlAttorney Docket No. 137174.00101 inclusive, 1 um, 2 um, 3 um, 4 um, 5 um, 6 um, 7 um, 8 um, 9 um, 10 um, or the like. In some embodiments, the amplitude for the ultrasonic sources 140, 142 can be about, e.g., 1- 100 um inclusive, 1-90 um inclusive, 1-80 um inclusive, 1-70 um inclusive, 1-60 um inclusive, 1-50 um inclusive, 1-40 um inclusive, 1-30 um inclusive, 1-20 um inclusive, 1- 20 um inclusive, 10-100 um inclusive, 20-100 um inclusive, 30-100 um inclusive, 40-100 um inclusive, 50-100 um inclusive, 60-100 um inclusive, 70-100 um inclusive, 80-100 um inclusive, 90-100 um inclusive, 20-80 um inclusive, 40-60 um inclusive, 1 um, 10 um, 20 um, 30 um, 40 um, 50 um, 60 um, 70 um, 80 um, 90 um, 100 um, or the like. In some embodiments, for achieving fusing functionality with the bottom up configuration, higher amplitudes in the 10-100 um inclusive range may be used. In some embodiments, for achieving the other functions discussed herein with the bottom up configuration, amplitudes in the 1-10 um inclusive range can be used. In some embodiments, an amplitude of greater than 10 um can be used to fuse PVDF material with the bottom up configuration, and the other functions can be achieved with PVDF material using the top down configuration with an amplitude of 10 um or less.

[0058] In some embodiments, the distance 160, 162 can be about 0 mm for a moving web 102 as the powder layer moves over the sonotrode horn (e.g., the edge 164). The powder particles 144 can thereby be in direct contact with the ultrasonic source 142. The “high” values in the table of FIG. 4 can refer to conditions where the web 102 is stationary or the sonotrode horn is applied consistently at a distance away from the deposited powder layer. In some embodiments, for both top down and bottom up configurations and for both moving and stationary web 102, the “high” value for the fusing function can be for an amplitude of about 11-100 um inclusive, the “low” value for the other functions (deagglomeration, resettling / leveling, compaction) can be for an amplitude of about 1-4 um inclusive, and the “high” value for the other functions can be for an amplitude of about 5- 10 um inclusive. In some embodiments, for distance in a top down configuration, “low” can refer to about 0-100 um inclusive, and “high” can refer to about 101-500 um inclusive, for all functions. In some embodiments, for distance in a bottom up configuration, “low” can refer to about 0 um for all functions and a moving web, “low” can refer to about 1-49 mm inclusive for all functions and a stationary web, and “high” can refer to about 50-100 mm inclusive for all functions and a stationary web. The processing time to achieve these functions can vary in the range of tens to hundreds of milliseconds depending on the amplitude “a” and distance 160, 162 values. Deagglomeration and resettling / levelling19MEl\58063819.vlAttorney Docket No. 137174.00101 functions may be important for layer thickness variation and quality, whereas compaction and fusing functions may be needed for high-speed calendering and processing capability of the dry powder coating.

[0059] According to some embodiments, the interaction between the ultrasonic source (or other means of applying ultrasonic energy, displacement, and / or motion to the battery powder on the conveying web) may prepare the electrode and coated powder for calendering. Preparation for calendering may involve, according to some embodiments, a rearrangement of the powder particles in the coating layer to deagglomerate, resettle, fuse, compact, densify, and / or otherwise modify the battery electrode powder after interaction between the ultrasonic source and the powder particles. The interaction between the ultrasonic source and the powder particles may cause one or more of these changes, and these changes may, e.g., cause an increase in cohesion within the battery electrode powder particles, cause an increase in adhesion between the battery electrode powder particles and the conveying web, cause an increase in uniformity of the packing of battery electrode powder particles on the web, or combinations thereof.

[0060] According to some embodiments, it may be desirable to reduce the mobility of the battery electrode powder during the calendering process, such that interactions between calender rollers and the battery electrode powder are substantially limited to compression of the battery electrode powder. The compression of the battery electrode powder during calendering is, according to some embodiments, substantially parallel to a line segment connecting the central axes of the calender rollers through which a coated web is directed for calendering. In particular, compression of the powder particles is performed by a force imparted on the powder particles by the calendering rollers substantially perpendicular to the web surface (and the web travel direction). In embodiments having top and bottom calendering rollers, the compression force occurs in-line with the central longitudinal axes of the respective calendering rollers.

[0061] During compression, the compressed battery electrode powder may expand in directions fore and aft of the distance of closest approaches of the calender rollers (also known as a calender nip), and this dilation of the powder particles may result in failure if the powder lacks sufficient strength to resist stresses generated by the dilation. According to some embodiments, the interaction between the ultrasonic source and the powder, and, specifically, the (alone or jointly) increases in adhesion, cohesion, and / or uniformity can reduce the appearance of imperfections such as, e.g., surface flaws, bare patches, regions20MEl\58063819.vlAttorney Docket No. 137174.00101 of variable sheen of the battery powder surface (such as regions which appear glossy or matte) or the like, which may occur during a calendering process.

[0062] The settings selected for operation of the ultrasonic sources 140, 142 can be made based on the type of material used in the powder particles 144. For example, in ultrasonic applications, a lower amplitude can be used for amorphous thermoplastics and a higher amplitude can be used for semi-crystalline thermoplastics. The polymer binder used in the mixed powder particles 144 for dry electrodes can generally be poly vinylidene fluoride (PVDF) materials, which are semi-crystalline in nature. Therefore, in some embodiments, higher amplitude (>=10 um and up to 100 um) can be used to achieve the fusing function for the bottom-up configuration for a fast-moving web 102 (e.g., a web 102 speed of greater than 1 m / min).

[0063] Such higher amplitude operation can advantageously improve traditional heating methods to melt or fuse the binder in the dry electrodes due to the operating temporal range. In particular, for a fast-moving web 102, traditional heated calender rollers generally cannot raise the coating temperature to the desired fusing or melting temperature of the binder. Similarly, a heating tunnel or oven can have larger footprint and energy cost to achieve the desired coating temperature at fast web 102 speeds. Conversely, higher amplitude ultrasonic vibrational energy provided by the ultrasonic source(s) 140, 142 can be applied from the bottom and / or top of the web 102 to effectively fuse or melt the binder in the powder layer at sub-second or hundreds of millisecond timescale, thereby enabling faster line speeds.

[0064] For the top-down configuration (FIG. 3), the sonotrode horn (with rounded edges 164) can be applied from the top of the deposited powder layer. In some embodiments, the central longitudinal axis of the ultrasonic device 142 can be oriented at an angle relative to the web 102 (e.g., 5-10 degrees inclusive, 5-9 degrees inclusive, 5-8 degrees inclusive, 5-7 degrees inclusive, 5-6 degrees inclusive, 6-10 degrees inclusive, 7- 10 degrees inclusive, 8-10 degrees inclusive, 9-10 degrees inclusive, 5 degrees, 6 degrees, 7 degrees, 8 degrees, 9 degrees, 10 degrees, or the like) to achieve an individual or a combination of the four functions (i.e., deagglomeration, resettling / leveling, compaction, fusion).

[0065] In some embodiments, a circular roller type sonotrode horn can be applied directly from the top (e.g., 90 degrees and perpendicular to the web 102) to achieve the21MEl\58063819.vlAttorney Docket No. 137174.00101 individual or combined functions. The distance 162 for such top-down configuration can be maintained at 0 or substantially close to 0. For example, in some embodiments, the edge 164 of the ultrasonic source 142 horn can be set at the same height or about, e.g., 10-50 um inclusive, 10-40 um inclusive, 10-30 um inclusive, 10-20 um inclusive, 20-50 um inclusive, 30-50 um inclusive, 40-50 um inclusive, 20-40 um inclusive, 10 um, 20 um, 30 um, 40 um, 50 um, or the like, lower than the incoming powder layer thickness 166 to ensure that the rounded or circular sonotrode horn touches the top surface of the deposited powder layer.

[0066] In some embodiments, a lower amplitude (e.g., less than about 5 um) for the ultrasonic vibrational energy can be applied in the top-down configuration to achieve the deagglomeration, resettling and compaction function together. However, low amplitude ultrasonic vibration may be ineffective in fusing and / or melting the PVDF binder. Therefore, the system 100 can include multiple sonotrode horns (i.e., ultrasonic sources 140, 142) with different geometries and application configuration in the dry powder processing lines to achieve customized on-demand and in-situ degrees of the four functions. For example, top-down for deagglomeration, resettling and compaction using one low amplitude sonotrode horn, and bottom-up for fusing using a second high amplitude sonotrode horn). In some embodiments, multiple ultrasonic sources 140, 142 can be used in each configuration and before / after / during respectively conditioning and calendering stages to achieve the desired functions in an optimized manner. The feedback control loop can assist with adjusting operation of the respective ultrasonic sources 140, 142 to optimize uniformity in the powder coating layer. The system 100 configuration can thereby be adjusted to ensure the desired deagglomeration, resettling / leveling, compaction and fusion functions are achieved to output a uniformly coated substrate.

[0067] While exemplary embodiments have been described herein, it is expressly noted that these embodiments should not be construed as limiting, but rather that additions and modifications to what is expressly described herein also are included within the scope of the invention. Moreover, it is to be understood that the features of the various embodiments described herein are not mutually exclusive and can exist in various combinations and permutations, even if such combinations or permutations are not made express herein, without departing from the spirit and scope of the invention.22MEl\58063819.vl

Claims

Attorney Docket No. 137174.00101CLAIMS:

1. A system for powder coating, comprising: a powder deposition unit configured to deposit powder particles onto a web; and at least one ultrasonic source configured to apply ultrasonic waves to at least a portion of the powder particles deposited on the web.

2. The system of claim 1, wherein application of the ultrasonic waves to at least the portion of the powder particles deposited on the web results in at least one of (i) deagglomeration, (ii) resettling, (iii) compaction, or (iv) fusion of the powder particles.

3. The system of claim 2, wherein a distance of the at least one ultrasonic source relative to the powder particles is adjustable and selected to achieve at least one of the (i) deagglomeration, (ii) resettling, (iii) compaction, or (iv) fusion of the powder particles.

4. The system of claim 2, wherein an amplitude of the at least one ultrasonic source is adjustable and selected to achieve at least one of the (i) deagglomeration, (ii) resettling, (iii) compaction, or (iv) fusion of the powder particles.

5. The system of claim 1, comprising a coating chamber through which the web moves from an upstream direction to a downstream direction, wherein the powder deposition unit is disposed within the coating chamber.

6. The system of claim 1, wherein the at least one ultrasonic source is a sonotrode disposed over a top surface of the web onto which the powder particles are deposited to apply the ultrasonic waves directly to at least the portion of the powder particles.

7. The system of claim 7, wherein the at least one ultrasonic source is disposed at a distance spaced from the powder particles to apply the ultrasonic waves directly to at least the portion of the powder particles in a spaced manner without physical contact between the at least one ultrasonic source and the powder particles.

8. The system of claim 1, wherein the at least one ultrasonic source is a sonotrode23MEl\58063819.vlAttorney Docket No. 137174.00101 disposed directly beneath and in contact with a bottom surface of the web to apply the ultrasonic waves to at least the portion of the powder particles through the web.

9. The system of claim 1, wherein an amplitude of the ultrasonic waves applied by the at least one ultrasonic source is varied based on a speed of the web.

10. The system of claim 1, comprising a first tension support element disposed upstream of the at least one ultrasonic source and a second tension support element disposed downstream of the at least one ultrasonic source, wherein the first and second tension support elements are configured to maintain a uniform tension of the web during passage through or near the at least one ultrasonic source.

11. The system of claim 1, comprising a conditioning assembly disposed downstream of the powder deposition unit and configured to condition the powder particles deposited on the web.

12. The system of claim 11, comprising a calendering assembly disposed downstream of the conditioning assembly, and wherein the ultrasonic waves applied by the at least one ultrasonic source prepares the powder particles for calendering in the calendering assembly via densification.

13. The system of claim 12, wherein the at least one ultrasonic source is configured to apply the ultrasonic waves to the powder particles during passage of the web and the powder particles through the calendering assembly to reduce a mobility of the powder particles during a calendering process.

14. The system of claim 12, wherein the at least one ultrasonic source is disposed between the conditioning assembly and the calendering assembly.

15. The system of claim 12, wherein the at least one ultrasonic source is disposed between components of the calendering assembly with the ultrasonic waves applied to at least the portion of the powder particles as part of a calendering operation.

16. The system of claim 11, wherein the at least one ultrasonic source is disposed24MEl\58063819.vlAttorney Docket No. 137174.00101 between the powder deposition unit and the conditioning assembly.

17. The system of claim 11, wherein the at least one ultrasonic source is disposed between components of the conditioning assembly with the ultrasonic waves applied to at least the portion of the powder particles as part of a conditioning operation.

18. The system of claim 1, comprising a sensor configured to detect a characteristic of the powder particles after application of the ultrasonic waves.

19. The system of claim 18, comprising a controller in communication with the sensor and configured to adjust at least one of (i) a speed of the web, or (ii) an amplitude of the ultrasonic waves generated by the at least one ultrasonic source, based on signals from the sensor indicative of the detected characteristic of the powder particles.

20. The system of claim 1, wherein the web is a metallic foil including at least one of Al, Cu, Ti, or a composite polymer film with metallized surfaces.

21. A system for powder coating, comprising: a powder deposition unit configured to deposit powder particles onto a moving web; a first ultrasonic source disposed over the moving web and configured to apply a first set of ultrasonic waves to at least a first portion of the powder particles deposited on the moving web; and a second ultrasonic source disposed below the moving web and configured to apply a second set of ultrasonic waves through the moving web to at least a second portion of the powder particles deposited on the moving web.

22. A method of powder coating, comprising: depositing powder particles onto a web with a powder deposition unit; and applying ultrasonic waves to at least a portion of the powder particles deposited on the web with at least one ultrasonic source.25MEl\58063819.vl

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