Coating system for formation of dry powder electrode

Abstract

An example coating system for formation of a dry powder electrode is provided. The system includes a coating chamber configured to receive a dry powder mixture, and further configured to receive a web including a top surface and an opposing bottom surface that travels through the coating chamber. The system includes an airflow system configured to control airflow passing through the coating chamber.

Description

Attorney Docket No. 137174.00100COATING SYSTEM FOR FORMATION OF DRY POWDER ELECTRODECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 700,423, filed on September 27, 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 spray 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 the1MEl\58073023.vlAttorney Docket No. 137174.00100 drying step from the manufacturing process, the overall process is simplified and becomes more economic, resulting in a viable alternative for large-scale manufacturing. In particular, the solvent-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 reduce the manufacturing cost of batteries.

[0004] In a conventional dry powder ESD coating system, a target substrate (e.g., a grounded electrically conductive substrate or web) passes continuously through a coating chamber while the dry powder mixture is dispensed from a hopper. An air supply system provides a high velocity air stream into the coating chamber to fluidize the dispensed powder and carry the fluidized powder particles to the electric field for electrostatically charging and to deposit on the web for distribution and coating. However, the use of high velocity air leads to an inherent kinetic energy of the power particles in the air stream as being a dominant force during deposition, which diminishes the ESD capability to produce a highly uniform coating of the powder particles on the web. Moreover, the flow pattern within the air stream in a chamber is not typically controlled and may result in non-uniform, irregular, or otherwise poorly controlled deposited thickness and loading (mass per area) attributes of the powder on the target material.

[0005] This lack of uniform coating is typically because the entire mass of powder particles must be diluted and carried in the air stream, which requires a high velocity to obtain a reasonable mass flow rate for production needs. In many systems, sufficient coating quality may only be achieved because of the insulative nature of the deposited powder particles which may hinder deposition in regions where powder particles are already deposited owing to electrostatic repulsion. Electrostatic repulsion based control is not typically realized when conductive particles are deposited, as charge on the electrically conductive particles conducts to the grounded target substrate. As such, conventional ESD coating systems, particularly those involving the deposition of conductive particles, are unable to offer a high degree of controlled uniformity of the powder particles on the web at high mass flow rates.SUMMARY

[0006] Embodiments of the present disclosure provide an electrostatic coating system capable of being used for coating a substrate or web with dry powder. The coating system includes a gas supply (e.g., an air supply, or the like) configured to direct laminar or2MEl\58073023.vlAttorney Docket No. 137174.00100 controlled turbulent air into the coating chamber to disperse and convey dry powder supplied from a powder metering unit. The coating system may optionally include an electrostatic system, to form an electrostatic coating system, to further direct the application of powder onto the substrate or web.

[0007] Embodiments of the present disclosure are directed to exemplary systems and methods for battery manufacturing. In certain embodiments, a substrate (as the term is used herein) can be a current collector. Current collectors are typically foil (thin sheets) of conductive metals such as aluminum, copper, or the like (including alloys thereof). These current collectors are often referred to as ’’webs” or a ”web” in the singular. In some embodiments, the web can range in thickness from between about, e.g., 5 and 20 um, inclusive, but in some instances can be between about 10 and 25 um, inclusive, and in other instances can be equal to or exceed about 25 um. The range of width of the web is also variable. Typical web widths are between about, e.g., 200 and 500 mm, inclusive, but may also be between about 300 and 600 mm, inclusive, 500 mm to 1 m, inclusive, 750 mm to 1.5 m, inclusive, or can exceed 1.5 m. The length of the web is also variable, and may exceed many thousands of meters.

[0008] The electrostatic coating system includes corona discharge producing electrodes positioned within the coating chamber configured to both electrostatically charge the dry powder particles within the coating chamber and also provide a guiding function to guide or direct the electrostatically charged powder particles towards the substrate or web. Thus, rather than relying solely on the high air flow for distribution of powder on the substrate or web (as done in conventional ESD systems), the exemplary coating system uses at least some of the electrodes within the coating chamber to guide the electrostatically charged powder particles, by controlling the airflow to a tight degree, thereby achieving a more uniform and operationally efficient distribution / coating of particles on the substrate or web.

[0009] In accordance with embodiments of the present disclosure, an exemplary electrostatic coating system is provided. The system includes a coating chamber configured to receive a dry powder mixture. The coating chamber is configured to receive a web including a top surface and an opposing bottom surface that travels through the coating chamber. The system includes electrodes disposed within the coating chamber. The electrodes operate as dual function electrodes by electrostatically charging particles of the3MEl\58073023.vlAttorney Docket No. 137174.00100 dry powder mixture introduced into the coating chamber, and once the particles of the dry powder mixture have been electrostatically charged, guiding the electrostatically charged particles towards the web. The created electric field between the electrodes and the web guides the charged powder particles to travel in the electric field towards the web.

[0010] In some embodiments, the system, via the inlet gas control device, can include an air supply means for directing air flow into the coating chamber to disperse the dry powder mixture over the web. In some embodiments, a turbulence control structure can be disposed upstream of the coating chamber and configured to control turbulence in the air flow to achieve laminar or turbulently controlled air flow prior to entry of the laminar air flow into the coating chamber.

[0011] The electrodes can be positioned in a narrowing configuration with a distance between adjacently positioned electrodes and the web gradually reducing in a downstream direction of the coating chamber. The narrowing configuration can be an arc configuration or a linear configuration shifting downwardly towards the web in the downstream direction of the coating chamber to guide the electrostatically charged particles towards the web for coating. Each of the electrodes in the narrowing configuration can be physically spaced from each other by both a vertical and horizontal distance relative to the web. Each of the electrodes can be capable of electrostatically charging the particles and guiding the electrostatically charged particles. In some embodiments, rather than (or in combination with) narrowing the distance between electrodes and the web, the position of the electrodes relative to the web can be uniform for adjacent electrodes and the field strength generated by each electrode can be changed by the applied voltage to each wire. For example, the electrode closest to the dispersion mechanism can have the smallest field strength and the subsequent electrodes can incrementally increase the field strength, thereby guiding the electrostatically charged particles towards the web surface.

[0012] In some embodiments, the system can include a deflection shield disposed within the coating chamber to control and limit the mobility of ions and charged particles formed by the corona discharge. The deflection shield can include at least one of a first section disposed at least partially below a dispensing roller to prevent return of the particles to the dispensing roller, a curved section (e.g., an electrode section) disposed above the narrowing configuration of the electrodes, combinations thereof, or the like. The electrode section of the deflection shield can define a geometry which follows the configuration of4MEl\58073023.vlAttorney Docket No. 137174.00100 the electrodes. An example of such is a curvature complementary to the narrowing configuration of the electrodes, with a distance of a first end of the electrode section further from the web than a distance of an opposing second end of the electrode section. In some embodiments, the electrode section can assist with guiding the electrostatically charged particles towards the web. In some embodiments, such guiding functionality can be achieved using a straight / linear configuration of the deflection shield, or other configurations.

[0013] In some embodiments, the system can include an exhaust assembly with negative pressure air to remove fugitive particles that have not coated the web. In some embodiments, the system can include a diffuser disposed upstream of the exhaust assembly. The diffuser can include a narrow opening oriented directly above the web.

[0014] In accordance with embodiments of the present disclosure, an exemplary electrostatic coating system is provided. The system includes a coating chamber configured to receive a dry powder mixture. The coating chamber is configured to receive a web including a top surface and an opposing bottom surface that travels through the coating chamber. The system includes electrodes disposed within the coating chamber in a narrowing configuration with a distance between adjacently positioned electrodes and the web gradually reducing in a downstream direction of the coating chamber. The electrodes operate as dual function electrodes by electrostatically charging particles of the dry powder mixture introduced into the coating chamber, the created electric field between the electrodes and the substrate guides the charged powder particles to travel in the electric field towards the substrate.

[0015] In accordance with embodiments of the present disclosure, an exemplary method of dry powder coating is provided. The method includes passing a web through a coating chamber of a coating system. The web includes a top surface and an opposing bottom surface. The method includes introducing a dry powder mixture into the coating chamber. The method may further include electrostatically charging particles of the dry powder mixture with electrodes disposed within the coating chamber. The method may include guiding the electrostatically charged particles towards the web with an electric field created between the web and the electrodes.

[0016] In accordance with embodiments of the present disclosure, an exemplary electrostatic coating system is provided. The system includes a coating chamber configured5MEl\58073023.vlAttorney Docket No. 137174.00100 to receive a dry powder mixture, and further configured to receive a web including a top surface and an opposing bottom surface that travels through the coating chamber. The system includes a dispensing assembly configured to dispense the dry powder mixture into the coating chamber. The system includes a charging assembly associated with the coating chamber. The system includes an airflow system configured to control airflow passing through the coating chamber.

[0017] In some embodiments, the charging assembly can include electrodes disposed within the coating chamber. The electrodes can operate as dual function electrodes by (i) electrostatically charging particles of the dry powder mixture introduced into the coating chamber, and (ii) once the particles of the dry powder mixture have been electrostatically charged, guiding the electrostatically charged particles towards the web.

[0018] The dry powder mixture includes active materials, binder, and conductive additives. In some embodiments, the dispensing assembly can include a hopper positioned over the coating chamber. The hopper can be configured to receive the dry powder mixture and introduce the dry powder mixture into the coating chamber. In some embodiments, the dispensing assembly can include a dispensing roller disposed below the hopper, the dispensing roller rotating to initially disperse the dry powder mixture into the coating chamber.

[0019] In some embodiments, the airflow system can include an air supply means for directing air flow into the coating chamber to disperse the dry powder mixture over the web. In some embodiments, the airflow system can maintain an air velocity of about 25- 750 fpm, inclusive, through the coating chamber. In some embodiments, the airflow system can include a turbulence controlling structure disposed upstream of the coating chamber and configured to control turbulence in the air flow. The turbulence controlling structure can be configured to control the turbulence in the air flow to achieve laminar air flow prior to entry of the laminar air flow into the coating chamber. The turbulence controlling structure can include an array of openings through which the air flow passes. In some embodiments, the openings of the array can each define a honeycomb configuration. In some embodiments, the turbulence controlling structure can define an open cross-sectional area between about 50-90%, inclusive. In some embodiments, the airflow system can include an air supply means for directing air flow into the coating chamber to guide the dry powder mixture introduced into the chamber towards the charging assembly.6MEl\58073023.vlAttorney Docket No. 137174.00100

[0020] In some embodiments, the electrodes can be positioned in a narrowing configuration with a distance between adjacently positioned electrodes and the web gradually reducing in a downstream direction of the coating chamber. In some embodiments, the narrowing configuration can be an arc configuration or a linear configuration shifting downwardly towards the web in the downstream direction of the coating chamber to guide the electrostatically charged particles towards the web for coating. Each of the electrodes in the narrowing configuration can be physically spaced from each other by both a vertical and horizontal distance relative to the web. Each of the electrodes can be capable of electrostatically charging the particles and guiding the electrostatically charged particles.

[0021] In some embodiments, the system can include a deflection shield disposed within the coating chamber to control mobility of ions and charged particles created by corona discharge. The deflection shield can include at least one of (i) a first section disposed at least partially below a dispensing roller to prevent return of the particles to the dispensing roller, and (ii) a curved section disposed above the narrowing configuration of the electrodes. The curved section can define a curvature complementary to the narrowing configuration of the electrodes, with a distance of a first end of the curved section further from the web than a distance of an opposing second end of the curved section. The curved section can assist with guiding the electrostatically charged particles towards the web. The airflow system includes an exhaust assembly with negative pressure air to remove fugitive particles that have not coated the web.

[0022] In accordance with embodiments of the present disclosure, an exemplary method of electrostatic dry powder coating is provided. The method includes passing a web through a coating chamber of an electrostatic coating system. The web includes a top surface and an opposing bottom surface. The method includes dispensing a dry powder mixture into the coating chamber with a dispensing assembly. The method includes controlling airflow passing through the coating chamber with an airflow system. The method includes charging particles of the dry powder mixture with a charging assembly.

[0023] Charging the particles of the dry powder mixture with the charging assembly can include electrostatically charging the particles of the dry powder mixture with electrodes of the charging assembly. In some embodiments, the method can include7MEl\58073023.vlAttorney Docket No. 137174.00100 guiding the electrostatically charged particles towards the web with the electrodes of the charging assembly.

[0024] In accordance with embodiments of the present disclosure, an exemplary coating system for formation of a dry powder electrode is provided. The system includes a coating chamber configured to receive a dry powder mixture, and further configured to receive a web including a top surface and an opposing bottom surface that travels through the coating chamber. The system includes an airflow system configured to control airflow passing through the coating chamber.

[0025] In some embodiments, the airflow system can include an air supply disposed at or near an inlet of the coating chamber to flow air through the coating chamber, the air supply creating a controlled pressure within the coating chamber. In some embodiments, the airflow system can include an air exhaust disposed at or near an outlet of the coating chamber to pull air through the coating chamber, the air exhaust creating a negative pressure within the coating chamber. In some embodiments, the airflow system can include both an air supply disposed at or near an inlet of the coating chamber to push air through the coating chamber, and an air exhaust disposed at or near an outlet of the coating chamber to pull air through the coating chamber, a combination of the air supply and the air exhaust creating a balanced draft system having a controlled pressure and velocity within the coating chamber.

[0026] In some embodiments, the air supply system can maintain an air velocity of about 25-750 fpm, inclusive, through the coating chamber. In some embodiments, the air supply system can maintain a static pressure of about -0.0001 to about -0.020 inches of water, inclusive, within the coating chamber. In some embodiments, the system can include one or more sensors disposed within the coating chamber to detect airflow and pressure measurements within the coating chamber. The system can include a controller configured to automatically adjust in real-time operation of the airflow system to maintain airflow and pressure within the coating chamber at desired levels (e.g., via a feedback control loop with the sensors).

[0027] In some embodiments, an inlet of the coating chamber can define a bell-mouth configuration with a decreasing cross-section. In some embodiments, the system can include a settling screen disposed at or near an inlet of the coating chamber to generate a controlled velocity profile through the coating chamber. In some embodiments, the air8MEl\58073023.vlAttorney Docket No. 137174.00100 supply system can be connected to an inlet of the coating chamber by an expansion section, the expansion section defining a gradual cross-sectional increase at an angle of about 5-9°, inclusive.

[0028] In some embodiments, the system can include a dispensing mechanism disposed over the coating chamber and configured to dispense the dry powder mixture from an outlet of the dispensing mechanism into the coating chamber. The airflow system can include means for directing airflow towards the outlet of the dispensing mechanism to disperse the dry powder mixture. In some embodiments, the means for directing airflow towards the outlet can include vanes or baffles angled upward relative to horizontal by an angle of about 5-50°, inclusive.

[0029] In some embodiments, the system can include a dispersion mechanism disposed at or near the outlet of the dispensing mechanism. The dispersion mechanism can be configured to act on the dry powder mixture to disperse the dry powder mixture. In some embodiments, the dispersion mechanism can include a tube with a hollow interior and holes formed therein. The tube can be configured to receive airflow through the hollow interior such that air is forced out of the holes to apply a force on the dry powder mixture. In some embodiments, the dispersion mechanism can include a screen with openings. The screen can be moved, translated, rotated or vibrated to disperse the dry powder mixture on and through the screen.

[0030] In some embodiments, the system can include a turbulence controlling structure disposed at or near an inlet of the coating chamber. The turbulence controlling structure can include an array of honeycomb openings configured to control turbulence in the airflow introduced into the coating chamber by the airflow system. In some embodiments, the system can include one or more turbulence controlling structures disposed at or near an inlet of the coating chamber. The one or more turbulence controlling structures can be configured to control turbulence in airflow introduced into the coating chamber by the airflow system such that lateral uniformity is less than about + / -5% root mean square (RMS) from a target.

[0031] In some embodiments, a distance between edges of the web and interior surfaces of the coating chamber can be at least about 0.1-6 inches, inclusive. In some embodiments, the system can include electrodes disposed within the coating chamber or within an electrode assembly with an interior in fluid communication with the coating chamber. At9MEl\58073023.vlAttorney Docket No. 137174.00100 least some of the electrodes can be configured to electrostatically charge the dry powder mixture introduced into the coating chamber. At least some of the electrodes can be configured to guide the electrostatically charged dry powder mixture towards the web for coating. In some embodiments, the system can include a powder reclaim system disposed adjacent to a proximal end of the web within the coating chamber. The powder reclaim system can be configured to capture the dry powder mixture that fails to coat the web.

[0032] In some embodiments, the dry powder mixture can include at least one of an active material, a conductive additive, or a binder. In some embodiments, the system can include a calendering assembly configured to compress the dry powder mixture on at least one of the top surface or the opposing bottom surface of the web to form a dry powder coating on the web.

[0033] In accordance with embodiments of the present disclosure, an exemplary method of coating for formation of a dry powder electrode is provided. The method includes passing a web through a coating chamber of a coating system, the web including a top surface and an opposing bottom surface. The method includes introducing a dry powder mixture into the coating chamber. In some embodiments, the method includes operating an airflow system to control airflow passing through the coating chamber. In some embodiments, the method includes controlling airflow passing through the coating chamber with an airflow system to guide electrostatically charged particles of the dry powder mixture.

[0034] In accordance with embodiments of the present disclosure, an exemplary coating system for formation of a dry powder electrode is provided. The system includes a coating chamber configured to receive a dry powder mixture, and further configured to receive a web including a top surface and an opposing bottom surface that travels through the coating chamber. The system includes an airflow system configured to control airflow passing through the coating chamber. The airflow system includes an air supply disposed at or near an inlet of the coating chamber to flow air through the coating chamber, the air supply creating a controlled pressure within the coating chamber. The airflow system includes an air exhaust disposed at or near an outlet of the coating chamber to pull air through the coating chamber, the air exhaust creating a negative pressure within the coating chamber. The system includes one or more sensors disposed within the coating chamber to detect airflow and pressure measurements within the coating chamber. The system10MEl\58073023.vlAttorney Docket No. 137174.00100 includes a controller configured to automatically adjust in real-time operation of the air supply and the air exhaust of the airflow system to maintain airflow and pressure within the coating chamber at desired levels.

[0035] In accordance with embodiments of the present disclosure, an exemplary electrostatic coating system is provided for formation of a dry powder electrode. The system includes a coating chamber configured to receive a dry powder mixture, and further configured to receive a web including a top surface and an opposing bottom surface that travels through the coating chamber. The system includes a charging assembly disposed within or adjacent to the coating chamber. The charging assembly is configured to electrostatically charge particles of the dry powder mixture introduced into the coating chamber, and guide the electrostatically charged particles towards the web.

[0036] In some embodiments, the system can include an airflow system configured to control airflow passing through the coating chamber. The airflow system can control the airflow to guide the dry powder mixture introduced into the chamber towards the charging assembly. In some embodiments, the airflow system can control the airflow to guide the electrostatically charged particles towards the web. In some embodiments, the airflow system can disperse the dry powder mixture within the coating chamber.

[0037] In some embodiments, the charging assembly can be disposed over the coating chamber and includes an opening in a bottom side such that an interior of the charging assembly is fluidly and aerodynamic ally open to an interior of the coating chamber. In some embodiments, the charging assembly can include a housing formed at least partially from a deflection shield to enclose an interior of the charging assembly, and prevent escape of the particles of the dry powder mixture and / or powder charging ions.

[0038] In some embodiments, the charging assembly can include a housing, a first set of electrodes disposed within an interior of the housing, and a second set of electrodes disposed within the interior of the housing. The second set of electrodes can be positioned offset from the first set of electrodes and in electrical isolation from the first set of electrodes. The first set of electrodes can be configured to electrostatically charge the particles of the dry powder mixture introduced into the coating chamber. In some embodiments, the first set of electrodes can be biased to provide an electric field strength of about 0.1-25 kV / cm, inclusive. The second set of electrodes can be configured to guide the electrostatically charged particles towards the web. In some embodiments, the first set11MEl\58073023.vlAttorney Docket No. 137174.00100 of electrodes can include charged wires positioned in a spaced manner along the same plane and extending a width of the charging assembly. In some embodiments, the second set of electrodes can include linear rod electrodes extending a width of the charging assembly.

[0039] The second set of electrodes can produce an electric field of varying strength and geometry to create a directed potential gradient for guiding the electrostatically charged particles towards the web. In some embodiments, the second set of electrodes can be in a form of a grid, a mesh, or plates. A distance between the second set of electrodes of the charging assembly relative to each other can be selected to increase an electric field uniformity generated by the electrodes. In some embodiments, the distance between electrodes relative to each other can be between about 1-20 cm, inclusive.

[0040] The dry powder mixture includes active materials, binder, and conductive additives. In some embodiments, an average powder velocity immediately downstream of the charging assembly can be between about 25-750 feet per minute, inclusive. In some embodiments, the system can include a dispensing mechanism disposed over the coating chamber and configured to dispense the dry powder mixture from an outlet of the dispensing mechanism into the coating chamber. In some embodiments, the system can include a dispersion mechanism disposed at or near the outlet of the dispensing mechanism, the dispersion mechanism configured to act on the dry powder mixture to disperse the dry powder mixture. In some embodiments, the dispersion mechanism can include a tube with a hollow interior and holes formed therein. The tube can be configured to receive airflow through the hollow interior such that air is forced out of the holes to apply a force on the dry powder mixture. In some embodiments, the dispersion mechanism can include a screen with openings. The screen is moved, translated, rotated or vibrated to disperse the dry powder mixture on and through the screen.

[0041] In some embodiments, electrodes of the charging assembly can create a varying electric field strength between the electrodes and the web in a downstream direction of the coating chamber to charge and guide the electrostatically charged particles towards the web. In some embodiments, electrodes of the charging assembly can create a varying electric field strength between the electrodes and the web which increase in strength in a downstream direction of the coating chamber. In some embodiments, electrodes of the charging assembly can create a varying electric field strength between the electrodes and the web which decreases in strength in a downstream direction of the coating chamber.12MEl\58073023.vlAttorney Docket No. 137174.00100

[0042] In some embodiments, electrodes of the charging assembly can produce a varying electric field strength relative to the web at equal vertical positions to the web and with varying potentials at individual electrode surfaces. In some embodiments, electrodes of the charging assembly can produce a varying electric field strength relative to the web at equal potentials at individual electrode surfaces and varying vertical and horizontal positions relative to the web. In some embodiments, electrodes of the charging assembly can be in a narrowing configuration which is an arc configuration or a linear configuration shifting downwardly towards the web in a downstream direction of the coating chamber to guide the electrostatically charged particles towards the web. In some embodiments, the charging assembly can include a corona charging mechanism. In some embodiments, the charging assembly can include a tribo-charging assembly.

[0043] In accordance with embodiments of the present disclosure, an exemplary method of electrostatic dry powder coating is provided. The method includes passing a web through a coating chamber of an electrostatic coating system, the web including a top surface and an opposing bottom surface. The method includes introducing a dry powder mixture into the coating chamber. The method includes electrostatically charging particles of the dry powder mixture with a charging assembly disposed within or adjacent to the coating chamber. The method includes guiding the electrostatically charged particles towards the web with the charging assembly.

[0044] In accordance with embodiments of the present disclosure, an exemplary system for manufacturing battery electrodes from a dry powder is provided. The system includes a web handling apparatus. The web handling apparatus can be configured to control a speed and tension of a web as the web is conveyed through a coating chamber. The system includes a dry battery electrode powder metering system. The system includes the coating chamber, which defines an internal cavity, the internal cavity is in gaseous communication with an upstream air supply device via a gas inlet and a downstream air exhaust device via a gas outlet. The coating chamber includes a web inlet and a web exit, and can be configured to accept the metered dry battery electrode powder for deposition of the dry battery electrode powder onto the web. The system includes an inlet gas control device disposed upstream of the coating chamber. The system includes an outlet gas control device disposed downstream of the coating chamber.13MEl\58073023.vlAttorney Docket No. 137174.00100

[0045] In some embodiments, the inlet gas control device can include a blower. In some embodiments, the inlet gas control device can include a turbulence control device including an inlet section and an outlet section. In some embodiments, the turbulence control device can include a series of parallel ducts. In some embodiments, the turbulence control device can produce a flow of gas at the outlet section with greater spatial uniformity as compared to a flow of gas at the inlet section. In some embodiments, the series of parallel ducts can be characterized by a length with characteristic size between about 2 and 50 mm, inclusive, and a wetted diameter with a characteristic size between about 5 and 100 mm, inclusive.

[0046] At least one of the coating chamber, the inlet gas control device, or the outlet gas control device can include a sensor configured to measure a mass flow of gas. At least one of the coating chamber, the inlet gas control device, or the outlet gas control device can include a sensor configured to measure a static pressure of gas. In some embodiments, the outlet gas control device can include a dust collector configured to apply a negative pressure at the gas outlet. In some embodiments, the inlet gas control device can include a blower configured to direct an amount of gas into the coating chamber via the gas inlet. In some embodiments, the application of the negative pressure can be controlled by a sensor located within at least one of (a) the coating chamber, (b) the inlet gas control device, or (c) the outlet gas control device.

[0047] In some embodiments, the coating chamber can include a series of rolling elements configured to handle or support the web. In some embodiments, the coating chamber can include one or more electrodes spaced a distance away from a free surface of the web to permit conveyance of the dry battery electrode powder between the web and the electrodes. In some embodiments, the electrodes can be biased at a first voltage relative to a second voltage on the web. In some embodiments, the second voltage can be held at a ground voltage. In some embodiments, the first voltage can be between about 5 and 100 kV, inclusive, relative to a ground voltage. In some embodiments, the first voltage can be between about -5 and -100 kV, inclusive, relative to a ground voltage.

[0048] In some embodiments, a wire can include the electrodes. In some embodiments, the wire can exhibit an average diameter of greater than about 10 um and less than about 200 um. In some embodiments, the first voltage can be a constant voltage. In some embodiments, the first voltage can be time-varying. In some embodiments, the time-14MEl\58073023.vlAttorney Docket No. 137174.00100 varying voltage can be at least one of a pulsed voltage, a cyclic full-wave voltage, or a cyclic half-wave voltage.

[0049] 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

[0050] To assist those of skill in the art in making and using the powder coating system, reference is made to the accompanying figures, wherein:

[0051] FIG. 1 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, with the electrostatic coating system in a horizontal orientation and electrodes in an arc configuration;

[0052] FIG. 2 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, with the electrostatic coating system in a vertical orientation and electrodes in an arc configuration;

[0053] FIG. 3 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, with a dual-sided simultaneous coating configuration and electrodes in an arc configuration;

[0054] FIG. 4 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, with a dual-sided offset coating configuration and electrodes in an arc configuration;

[0055] FIG. 5 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, with a single-sided in series coating configuration and electrodes in an arc configuration;

[0056] FIG. 6 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, with the electrostatic coating system in a horizontal orientation and electrodes in a linear configuration;15MEl\58073023.vlAttorney Docket No. 137174.00100

[0057] FIG. 7 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, including mechanical dispersion means;

[0058] FIG. 8 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, including gravity dispersion means;

[0059] FIG. 9 is a diagrammatic side view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, with an electrostatic charging assembly;

[0060] FIGS. 10A-D are diagrammatic perspective (FIG. 10A), side (FIG. 10B), top (FIG. 10C), and exploded (FIG. 10D) views of an exemplary electrostatic charging assembly of an exemplary electrostatic coating system of FIG. 9;

[0061] FIGS. 11A-C are diagrammatic views of electric field lines generated by an electrode of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, including a single electrode (FIG. 11 A), two adjacent electrodes (FIG. 1 IB), and a single elongated electrode (FIG. 11C);

[0062] FIGS. 12 is a diagrammatic view of airflow in an exemplary coating system in accordance with embodiments of the present disclosure, including additional air inlets;

[0063] FIG. 13 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, including an air supply system in a push configuration;

[0064] FIG. 14 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, including an air supply system in a pull configuration;

[0065] FIG. 15 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, including an air supply system in a balanced draft (push and pull) configuration;

[0066] FIG. 16 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, including an expansion inlet for a push or balance draft system;16MEl\58073023.vlAttorney Docket No. 137174.00100

[0067] FIG. 17 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, including an angle of inclination of inlet air flow;

[0068] FIG. 18 is a diagram of reference angles for an exemplary electrostatic coating system of FIG. 17 including an angle of inclination of inlet air flow;

[0069] FIG. 19 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, including inlet airflow for inducing particle dispersion;

[0070] FIG. 20 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, including a vibrating sieve for inducing particle dispersion;

[0071] FIG. 21 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, including a multi-rod surface for inducing particle dispersion;

[0072] FIG. 22 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, including an air injection tube for inducing particle dispersion;

[0073] FIGS. 23A-C are diagrammatic views of powder dispersion devices for an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, including a single airflow tube (FIG. 23A), multiple airflow tubes (FIG. 23B), and an airfoil- shaped tube (FIG. 23C);

[0074] FIG. 24 is a perspective view of an inlet section for a coating chamber of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure;

[0075] FIG. 25 is a perspective view of a powder reclaim system of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure;

[0076] FIG. 26 is a diagrammatic view of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure, including a tribo-charging configuration; and17MEl\58073023.vlAttorney Docket No. 137174.00100

[0077] FIG. 27 is a block diagram of an exemplary electrostatic coating system in accordance with embodiments of the present disclosure.DETAILED DESCRIPTION

[0078] The exemplary electrostatic coating system includes air dispersion of a dispensed powder stream for a continuous moving web, and further includes electrodes configured to electrostatically charge the powder particles by means of corona discharge and provide a guiding force to the electrostatically charged particles to direct the particles as a uniform coating on the web with high uniformity and high first pass transfer efficiencies. In some embodiments, all electrodes of the system can be configured to provide both a charging functionality and a guiding functionality. In some embodiments, some electrodes can be used exclusively to provide a charging functionality and some electrodes can be used exclusively to provide a guiding functionality. In some embodiments, the type of functionality of the electrodes can be dependent on a distance of the electrode position relative to the powder dispensing machine output, with electrodes closest to the output providing more of the charging functionality, electrodes furthest to the output providing more of the guiding functionality, and electrodes in-between providing both the charging and guiding functionality. The position and / or spacing of the electrodes within the coating and / or electrostatic charging chamber is described herein as only exemplary, and it should be understood that alternative positions of the electrodes could be used, e.g., the electrode positioning described in International Patent Application No. PCT / US23 / 26276, filed on June 27, 2023, which is incorporated herein by reference in its entirety.

[0079] The system decouples the powder carrying / conveying process (e.g., dispensing) from the dispersion air stream by using a powder dispensing mechanism (e.g., a roller and / or brush in some non-limiting embodiments) to dispense the powder along the width of the web and includes an air supply that provides a uniform laminar air stream to disperse the powder stream longitudinally down the web direction. The dispersion of the powder stream reduces the powder cloud density (e.g., powder stream) coming out of the powder dispensing roll feeding the ESD charging zones to ensure that there is efficient powder charging with the number and / or location of wire electrodes disposed within the chamber. Although discussed with respect to a horizontal orientation and a vertical orientation of the system, it should be understood that the system can be used in any orientation (e.g., any18MEl\58073023.vlAttorney Docket No. 137174.00100 angle between the horizontal or 0° orientation and the vertical or 90° orientation). The system can therefore be orientation agnostic, with appropriate adjustment of the air stream generation position / direction and the direction of flow of the powder. In some embodiments, the system can be used to provide simultaneous dual-sided coating of the web.

[0080] In some embodiments, the system allows for the use of highly laminar or highly controlled turbulent, uniform air as a down-web dispersion mechanism for a dense dispensed powder stream into an electrostatic charging zone. The air supply assembly or system can be any type known in the industry, e.g., a cyclone vacuum, a positive pressure blower, a negative pressure blower, combinations thereof, or the like. The air supply system can provide filtered and diffused air into the coating chamber. The air source can either be a “push” system or “pull” system, or a combination of both, to create a balanced draft.

[0081] In some embodiments, in an effort to reduce the effective Reynolds number where the air carries the powder particles, specific air inlet designs can be utilized alone or in combination. Such specific air inlet designs can be referred to herein as “turbulence reducing devices” or “turbulent controlling devices”, and can enable a shorter development length to reduce the overall footprint of the system. In some embodiments, the air intakes can incorporate individually or in combination the following features: bell mouth shaped intakes, diffusion meshes, vanes which can be dynamic or stationary, converging and / or diverging sections, or the like. In some embodiments, the Reynolds number can be increased at the injection point, while still obtaining a controlled and uniform velocity entering the coating chamber which will allow for coating uniformity. The diffusion meshes can take the form of, but are not limited to, honeycomb opening arrays and perforated plates of potentially varying widths. There diffusion meshes are typically between about, e.g., 50- 90% inclusive, 50-80% inclusive, 50-70% inclusive, 50-60% inclusive, 60-90% inclusive, 70-90% inclusive, 80-90% inclusive, 60-80% inclusive, 50%, 60%, 70%, 80%, 90%, or the like, open area. Each of these features can be specifically calculated based on the coating chamber cross-sectional area and the target conveying velocity to ensure an effective result / operation. In some embodiments, the target conveying velocity can be between about e.g., 25-750 FPM inclusive, 100-750 FPM inclusive, 200-750 FPM inclusive, 300-750 FPM inclusive, 400-750 FPM inclusive, 500-750 FPM inclusive, 600-750 FPM inclusive, 25-700 FPM inclusive, 25-600 FPM inclusive, 25-500 FPM inclusive, 25-400 FPM inclusive, 25-300 FPM inclusive, 25-200 FPM inclusive, 25-100 FPM inclusive, 200-60019MEl\58073023.vlAttorney Docket No. 137174.00100FPM inclusive, 300-500 FPM inclusive, 25 FPM, 100 FPM, 200 FPM, 300 FPM, 400 FPM, 500 FPM, 600 FPM, 700 FPM, 750 FPM, or the like, in the machine direction. In some embodiments, the velocity range can be about, e.g., 50-500 FPM inclusive, or the like. The required volumetric flow rate can be calculated based on the target velocity, the chamber cross sectional area, and the pressure drops within the system.

[0082] To enable a high degree of coating uniformity, the air steam should have a certain uniformity. The uniformity of the air is most important in regards to the cross-web direction. The lateral uniformity should be less than about + / -5% root mean square (RMS). The air velocity uniformity in the z direction (height) can have a gradient as long as the lateral uniformity is maintained. It should be noted that these target air uniformities are required when the powder dispensing stream is uniform to the coating requirements. There can be non-uniformities induced into the air conveying stream to compensate for nonuniformities in the powder dispensing stream to achieve a target coating uniformity. As such, means for inducing turbulence or other means to compensate for non-uniformities in the powder dispensing stream can be incorporated into the system. In some embodiments, turbulence can be induced by, e.g., providing cross flow air streams, increasing the velocity, increasing the characteristic length of the system, creating geometric non-uniformities in the air diffusion meshes, mechanical oscillation, generally any disturbance to the air stream in a controlled manner, combinations thereof, or the like. The system includes a tail pipe configured to remove the fugitive powder via vacuum without disturbing the air stream (in the case of a push system) or enable the air stream (in the case of a pull system) within the coating chamber, ensuring a uniform coating of the web. In the case of a pull system, the air stream creation vacuum and the powder collection vacuum could be configured as one unit. To achieve a target static pressure within the coating chamber, a combination of a push and pull system can be utilized for finer control and tunability of the system performance. In some embodiments, a target static pressure of about- 0.001 - -0.020 inches of water column, inclusive, allows for optimal control ranges ( + / -0.002 or less In.WC).

[0083] According to some embodiments, the coating system can utilize, and as described herein, may prepare a coating of dry powder for a subsequent step, such as a calendering operation. A calendering operation may be utilized to planarize, set, compress, densify, or otherwise apply a pinching force to a powder on a continuously moving web. A calendering operation is typically performed by a calendering machine. A calendering machine may include a pair of rollers which may form a nip at the location of closest20MEl\58073023.vlAttorney Docket No. 137174.00100 approach of the surfaces of the pair of rollers. A conveying web coated with a dry powder may be configured to pass through the nip, and the calendering rollers may be controlled at a fixed gap and / or compressing pressure (or force) such that a material, such as a dry powder coated web, may interact with the calendering rollers to compress the dry powder and the web. During compression, the dry powder may density and decrease in thickness, such that an input density of the dry powder and an input height of the dry powder may be modified by the calendering operation. After the calendering operation, the dry powder may exhibit an output density which is greater than the input density and an output height which is lower than the input height (with input referring to before passage through the calendering operation, and output referring to after passage through the calendering operation). Moreover, any variation in the height of the powder may be modified in the calendering operation, such that an output height variation (such as a stand deviation in the input height) may be smaller as compared to the output height variation (such as a standard deviation in the output height).

[0084] In some embodiments, as illustrated in FIG. 12, the coating system 1250 can utilize one or more additional inlets 1264, 1268 to provide air to the coating chamber 1252. The system 1250 generally includes an inlet 1256 that receives the bulk of the inlet air 1260 from a fan or other source, and outlet 1258 from which air is exhausted, and a web 1254 that travels through at least a portion of the coating chamber 1252. The system 1250 includes a powder inlet 1266 for introducing powder particles into the coating chamber 1252. In some embodiments, an additional air inlet 1264 can be located at the top of the coating chamber 1252 adjacent to the powder inlet 1266, and can introduce air perpendicularly or at an angle relative to the top of the coating chamber 1252. In some embodiments, the powder inlet 1266 can be located near or at the bottom of the inlet 1256 instead of the top of the coating chamber 1252. For example, in some embodiments, the additional inlet air 1264 can be introduced at an angle 1262. In some embodiments, an additional air inlet 1268 can be located downstream of the powder inlet 1266, and can also introduce air perpendicularly or at an angle relative to the top of the coating chamber 1252. Flow velocity and / or pressure can be controlled for each of the additional air inlets 1264, 1268. It should be understood that one or more additional air inlets 1264, 1268 could be incorporated into the system 1250. These additional air inlets 1264, 1268 can be arranged such that the powder particles can be guided and / or dispersed in addition to the original guidance and dispersion provided by the main air inlet 1256 for the coating chamber 1252.21MEl\58073023.vlAttorney Docket No. 137174.00100Additional air inlets 1264, 1268 can incorporate the previously described features to control turbulence such as: bell mouth shaped intakes, diffusion meshes, vanes which can be dynamic or stationary, converging and / or diverging sections, combinations thereof, or the like. In some embodiments, the angle 1262 of approach and location of the additional inlets 1264, 1268 can be set to guide the particle powder path in a desired direction, e.g., towards the electrode assembly or towards the web 1254. Further, additional air inlets 1264, 1268 can be arranged at the powder dispensing zone to disperse the powder in a controlled manner to better enable subsequent deposition. In some embodiments, these additional air inlets 1264, 1268 can be arranged to passively flow air over the electrodes to prevent powder buildup which could critically amass and fall onto the web 1254 as clumps, creating a defect in the uniform coating. For the described additional air inlets 1264, 1268, the airflow and pressure of each inlet can be controlled to achieve the desired function, powder guidance, dispersion, cleaning, or the like, while not disrupting the controlled airflow from the coating chamber’s main air intake and exhaust.

[0085] The system includes multi-functional wire electrodes strategically disposed within the coating chamber to charge and direct / guide the powder path within the coating chamber, thereby ensuring a uniform coating of the web. Such dual function of the electrodes increases transfer efficiency and improves the system reliability by minimizing or eliminating powder build up on the electrode (e.g., wire electrode) surfaces and the chamber walls. The system includes wire electrodes with two different functions. A first set of electrodes can be the traditional “corona discharge powder charging wire electrodes”. The second set of electrodes are the “guiding electrodes” (e.g., guiding wire electrodes, or the like). The charging wire electrodes are positioned in locations within the coating chamber based on the powder dispensing stream and initial dispersion area from the uniform air stream, such that the majority of the powder is charged.

[0086] The charged particle cloud continues to be conveyed by the air stream, but now travels in the direction of the electric field lines formed between the multi-functional electrodes and the target coating substrate due to the charge on the powder particles. The guiding function of the electrodes assist with directing or guiding the powder cloud to the desired areas of the web. The guiding electrodes can produce similar plasma zones (e.g., corona discharge, or the like), which effectively produce zones of charged ions, modifying the electric field line vectors which impart forces on the charged powder particles in the desired location, e.g., towards the web. In some embodiments, the guiding electrodes can22MEl\58073023.vlAttorney Docket No. 137174.00100 function to reduce the magnitude of the powder velocity vector in the machine direction by imparting vectors of electric field forces on the charged particle towards the web, enabling the electrostatic forces to be the dominant force during deposition. The guiding electrodes can be placed in strategic locations relative to the general charged powder particle flow such that the flow of the charged powder particle cloud is further directed towards the web.

[0087] In some embodiments, the guiding wire electrodes can be disposed in a downward arc or downward linear direction towards the web (see, e.g., FIG. 1), guiding / conditioning the powder path. The downward direction of the electrodes is referred to herein as a “narrowing configuration”, and is intended to describe the gradually narrower or reduced distance between the electrodes and the surface of the web in the downstream direction to direct / guide the powder path towards the surface of the web. Although an arc and linear configuration are illustrated, it should be understood that alternative narrowing configurations / positions of the electrodes are also envisioned. In some embodiments, the guiding wire electrodes can be disposed in a rightward or leftward arc towards the web (see, e.g., FIG. 2), guiding / conditioning the powder path. As noted herein, the position and / or spacing of the electrodes within the coating chamber is described herein as only exemplary, and it should be understood that alternative positions of the electrodes could be used, e.g., the electrode positioning described in International Patent Application No. PCT / US23 / 26276, filed on June 27, 2023, which is incorporated herein by reference in its entirety. In general, the charging wire electrodes should maintain a minimum spacing between other conductive elements, such as other wire electrodes or the grounded web, to minimize / eliminate electrical breakdown in the form of arcing (e.g., based on a function of the applied voltage to the wire). Typically, for voltages used in the ESD application, the spacing can be at least about 1 cm. In some embodiments, the wire electrodes can be, e.g., less than about 45 cm from each other and / or from the web, e.g., less than about 30 cm from each other and / or from the web, or the like.

[0088] The system can include a plasma deflection shield within the coating chamber to limit the mobility of the ionized air out of the “guiding zone”, e.g., the zone in which the guiding wire electrodes direct the powder towards the web. The shield can be to isolate the charged powder path from attracting towards the dispensing roll. When charging is first occurring, the powders are highly likely to be closer to the dispensing machine than the web, influencing the flow direction. As such, the shield can be used to prevent attraction of the charged powder path towards the dispensing roll. In some embodiments, the23MEl\58073023.vlAttorney Docket No. 137174.00100 dispensing roll can be fully insulated to eliminate risks of powder coating onto the roll or any other conductive surfaces in the system. This can provide additional protection over the deflection shield.

[0089] In some embodiments, the system can incorporate integrated one or more powder reclaim systems for any over sprayed powder which is not collected by the fugitive powder collection vacuum. The power reclaim system can be in the form of one or more configurations that can be implemented individually or in combination. When integrated with the coating system, the powder reclaim system can be configured to prevent inducement of non-uniformities in the air carrying stream, which can be carefully catered to the function of uniform deposition. Some embodiments of this system can include: a belt conveyor, a screw feeder, a vacuum system, combinations thereof, or the like. Depending on the orientation of the coating chamber, the additional features of the system can be adjusted to maximize their operation effectiveness.

[0090] Although the system discussed herein is described as a single coating module, it should be understood that in some embodiments, the coating modules can be combined in a variety of forms and / or configurations. In some embodiments, the coating modules can be situated vertically on a single side or mirrored onto the second side of the web to achieve a dual-sided simultaneous coating processes (see, e.g., FIG. 3). In some embodiments, the coating modules can be offset (see, e.g., FIG. 4). In some embodiments, the coating modules can be placed in series such that the output of one module is fed as input to be the subsequent module, with each coating module applying a coating to the web. In some embodiments, any number of coating modules can be combined in series to achieve the desired coating outcome. FIG. 5 shows such in series configuration for a horizontal orientation of the system, although a similar arrangement could be incorporated into a vertical orientation of the system.

[0091] FIG. 1 is a diagrammatic view of an exemplary electrostatic coating system 100 (hereinafter “system 100”) in a horizontal orientation. The system 100 includes an electrostatic coating chamber 102 that receives a continuously moving substrate or web 104. The web 104 travels through the chamber 102 along a direction 106, referred to as a machine direction (MD), and the orthogonal direction can be referred to as the cross direction (CD). The horizontal orientation refers to a chamber 102 that allows the web 104 to move in a left-to-right or right-to-left direction, e.g., substantially parallel to horizontal.24MEl\58073023.vlAttorney Docket No. 137174.00100

[0092] At a top section, the system 100 includes a hopper 108 configured to receive a dry powder mixture 110. In some embodiments, the walls of the hopper 108 can angle inwardly towards each other and the bottom space of the hopper 108 to maintain a substantially constant level of the powder mixture 110 along the width and / or length of the hopper 108. For example, the hopper 108 can define a substantially V-shaped crosssection. The top of the hopper 108 can be open to receive the powder mixture 110, and the opposing end defines an outlet opening 112 that is disposed directly above a powder dispensing roller 114 (e.g., a roller that allows for dispensing and / or scattering of powder). The roller 114 rotates along an axis 116 that extends along the cross direction over the width of the web 104. As the powder mixture 110 drops on the roller 114, the roller 114 begins to initially disperse the powder mixture 110 in an initial dispersion zone 118 relying on the force of gravity.

[0093] The system 100 includes an air supply system 120 disposed outside of the chamber 102 and directing air (laminar and / or controlled turbulent) into the chamber 102. In some embodiments, laminar air flow can be used to more effectively disperse the powder cloud. Laminar air flow can be used to disperse the powder cloud in a controlled manner that enables the electrostatics of the system 100 to be the dominant force during disposition. However, in some embodiments, the system 100 can be used with turbulent air flow and the electrodes can provide the same charging and guiding effect, as discussed herein. In a system 100 having turbulent air flow, the position of the electrodes may be adjusted to ensure proper charging and guiding can be achieved even with the faster movement of particles within the coating chamber 102.

[0094] Therefore, in some embodiments, the system 100 can operate with only laminar air flow (as compared to conventional systems), but could also be incorporated into a turbulent air flow system if needed. The system 100 can include a turbulence controlling structure 122 disposed outside of the chamber 102 with multiple openings 124 through which the supplied air passes in horizontal direction 126 before entry into the chamber 102. In some embodiments, the openings 124 can be in the form of a honeycomb pattern, although alternative opening 124 configurations are envisioned. Air that has passed through the structure 122 is filtered and diffused before passage into the chamber 102. The configuration of the structure 122 can also serve to control turbulence in the air flow introduced into the chamber 102. The air introduced into the chamber 102 is directed at the powder mixture 110 dropping towards the web 104 from the initial dispersion zone 118.25MEl\58073023.vlAttorney Docket No. 137174.00100Such interaction with the air results in the powder mixture 110 being further dispersed over the web 104 within a main dispersion zone 128 (e.g., a dispersed powder cloud).

[0095] The system 100 includes multiple electrodes 130-142 (e.g., corona discharge electrodes, guiding electrodes, an electrode web or net, or the like) selectively positioned within the chamber 102. In some embodiments, electrodes 130, 132 can be disposed within the chamber 102 adjacent to the wall associated with the air input. The electrodes 130, 132 can be vertically spaced from each other, and provide an electrostatic charge to the particles of the powder mixture 110 within the initial dispersion zone 118 and the main dispersion zone 128. In some embodiments, the electrodes 130, 132 can also act as guiding electrodes for guiding the electrostatically charged particles towards the web 104. However, most of the guidance to the particles at the location of the electrodes 130, 132 can be provided by the air flow introduced into the chamber 102.

[0096] The electrode 134 can be disposed on the opposing side of the roller 114 and horizontally spaced from the electrode 130. In some embodiments, the height of the electrode 134 within the chamber 102 can be substantially similar to the height of the electrode 130. The electrodes 136-142 can be incrementally spaced / offset from each other (both horizontally and vertically relative to the web 104), starting from the electrode 134, both horizontally and vertically to define a downward arc 174 in the direction of the web 104. The position of the electrodes 136-142 therefore moves further from the air supply intake and further down towards the web 104 (e.g., a narrowing configuration). The distance of the electrodes 134-142 from the top surface 144 of the web 104 (e.g., or the web 104 in general) therefore decreases in the downstream direction of the coating chamber 102. The electrodes 136-142 can provide both an electrostatic charging function and a guiding function, depending on whether the particles within the zone 128 have been charged. In general, the electrodes 134-142 furthest from the roller 114 can provide more of the guiding functionality, while electrodes 134-142 closest to the roller 114 can provide more of the charging functionality. However, the transition between charging and guiding can be gradual, and can be shared by one or more electrodes.

[0097] For example, electrode 134 can primarily provide a charging functionality to the powder cloud. As the powder cloud moves further within the zone 128, more particles become electrostatically charged. Therefore, while electrode 136 can still provide a charging functionality (less than electrode 134), electrode 136 can begin to provide a26MEl\58073023.vlAttorney Docket No. 137174.00100 guiding functionality as well for guiding the charged particles downward towards the web 104. Electrode 138 can provide less charging functionality and more guiding functionality than electrode 136. Electrode 140 can provide less charging functionality and more guiding functionality than electrode 138. Electrode 142 can provide less charging functionality and more guiding functionality than electrode 140.

[0098] The web 104 includes a substantially planar top surface 144 and a substantially planar bottom surface 146. Although discussed herein as being used to coat the top surface 144, the system 100 could be configured to similarly coat the top and bottom surfaces 144, 146. Upon initial entry into the chamber 102, the top surface 144 is uncoated. As the web 104 travels in direction 106 within the chamber 102, the dispersed particles begin to drop onto and coat the top surface 144. While the air flow into the chamber 102 disperses the particles, the electrodes 130, 132, 134 (and optionally electrodes 136-142) can electrostatically charge the particles. The electrodes 136-142 (and optionally electrodes 130-134) providing a guiding function for directing the electrostatically charged particles downward towards the top surface 144 of the web 104, ensuring a uniform coating. The electrodes 130-142 of the system 100 can therefore provide simultaneous charging and guiding to the particles. In particular, the electrostatically charged particles are repelled by similar charges and the associated electric fields. The electrodes 136-142 (and optionally electrodes 130-134) produce similar plasma zones (e.g., corona discharge, or the like), which effectively produce a wall of negatively charged ions, repelling the charged powder particles in the desired location, e.g., towards the top surface 144 of the web 104. The electrodes 130-142 of the system 100 therefore serve a dual functionality, which advantageously results in a uniform coating of the web 104 at coated web section 148. In some embodiments, the voltage for the electrodes 130-142 can be varied or different depending on the type of function being performed. For example, electrodes 130-142 performing primarily a charging function can have a different voltage from electrodes ISO- 142 that primarily perform a guiding function. Electrodes 130-142 that are configured to serve both a charging and guiding function in a substantially equal manner can have the same or substantially same voltage.

[0099] In some embodiments, the system 100 can include a plasma deflection shield 150 disposed within the chamber 102. The shield 150 can be formed to limit the mobility of charged particles within the guiding zone, although the shield 150 can provide protection in other areas of the chamber 102 as well. For example, one section 152 of the shield 15027MEl\58073023.vlAttorney Docket No. 137174.00100 can define a substantially semicircular shape complementary to the curvature of the roller 114, and is disposed immediately below the roller 114. The section 152 is offset from the zone 118 to allow for the powder particles to drop from the roller 114 and into the zones 118, 128. The section 152 can prevent or reduce passage of powder particles towards the roller 114, thereby eliminating the risk of powder coating onto the roller.

[0100] The shield 150 includes a curved section 154 that extends from a first end 156 at the end of the section 152 to a second end 158 downstream of the electrode 142. The curved section 154 of the shield 150 is disposed above the electrodes 134-142 and can generally mimic or be complementary to the curved positioning of the electrodes 134-142. The curved section 154 therefore curves downwardly from an area near the roller 114 towards the web 104. The curved section 154 deflects any particles that may pass between the electrodes 134-142 back towards the web 104. Although illustrated with two electrodes 130-132 at the air intake and five electrodes 134-142 above the zone 128, it should be understood that more or less electrodes could be used to ensure sufficient electrostatic charging and to achieve the desired guidance effect.

[0101] At the downstream end of the chamber 102, the system 100 includes an exhaust assembly 160 for removing any unused powder particles 162 and recycling such particles 162 for future use. The exhaust assembly 160 can include a diffuser 164 with an opening 166 in the walls disposed directly above the top surface 144 of the coated web 104 such that any loose particles 162 can be captured. The inner walls of the diffuser 164 can include one or more diffuser / distributor flanges 168. The diffuser 164 connects to an exhaust duct 170 that has negative pressure air forced in direction 172 for exhaust of the fugitive powder from the chamber 102. The exhausted powder can be collected and reused (e.g., reintroduced into the hopper 108) for coating of the web 104. The system 100 therefore provides an efficient and effective way of dispersing a dry powder cloud over the web 104 for electrostatic charging, and uses electrodes in a dual function manner to provide guidance to the electrostatically charged particles to direct such particles to the top surface 144 of the web 104. The combination of charging and guiding functionalities of the electrodes ensures a high uniformity of the coating at high mass flow rates of the powder.

[0102] In some embodiments, rather than an electrode-based corona charging system, the system can include a tribo-charging configuration. For example, FIG. 26 illustrates a system 1200 that is substantially similar in structure and function to the system 100, except28MEl\58073023.vlAttorney Docket No. 137174.00100 for the distinctions noted herein. The coating chamber 102 can include one or more tribocharging mechanisms 1202. The tribo-charging mechanisms 1202 can be distributed within the coating chamber 102 in areas in which the mechanism 1202 will interact with powder particles introduced into the coating chamber 102. In some embodiments, the tribo- charging mechanism 1202 can be incorporated into the system 1200 as, e.g., the dispensing roller 114, one or more units arranged along the powder travel path within the coating chamber 102, rods along the powder travel path, plates along the powder travel path, or the like. The tribo charge mechanism 1202 includes a material, e.g., PTFE, PVDF, glass, combinations thereof, or the like, that interact with the powder particles to transfer a charge to the powder particles. Thus, the tribo-charging process can occur where powder particles interact with the material of the mechanism 1202 (and / or the dispensing roller 114 having such material). It should be understood that the tribo-charging configuration can be incorporated into any of the systems discussed herein, such that the system relies on either tribo-charging, electrode (corona) charging, or a combination of both.

[0103] FIG. 2 is a diagrammatic view of an exemplary electrostatic coating system 200 (hereinafter “system 200”) in a vertical orientation. The system 200 can be substantially similar in structure and / or function to the system 100, except for the distinctions noted herein. The system 200 includes an electrostatic coating chamber 202 that receives a continuously moving substrate or web 204. The chamber 202 is oriented vertically such that the web 204 travels from an upper position to a lower position, e.g., substantially perpendicular to horizontal. The machine direction 206 of the system 200 is therefore downward rather than side-to-side. The systems discussed herein can be orientation agnostic, e.g., oriented at any angle between the horizontal orientation of system 100 and the vertical orientation of system 200.

[0104] The system 200 also includes a hopper 208 that receives a dry powder mixture 210 for output through a bottom opening 212. The hopper 208 defines a V-shaped configuration with tapered walls to guide the powder mixture 210 towards the opening 212. The opening 212 is positioned directly above a powder dispensing roller 114 that rotates along axis 216 to initially disperse the powder mixture 210 in the initial dispersion zone 218 relying on the force of gravity.

[0105] The system 200 also includes an air supply system 220 disposed outside of the chamber 202. Rather than supplying air into the chamber 202 in a direction substantially29MEl\58073023.vlAttorney Docket No. 137174.00100 parallel to the machine direction (as done in the system 100 of FIG. 1), the system 220 supplies air into the chamber 202 in a direction perpendicular to the machine direction 206. Air from the system 220 travels along direction 226 through a filtration and / or diffusion structure 222 having an array of openings 224 (e.g., honeycomb openings, or the like) before entry into the chamber 202. Air entering into the chamber 202 further disperses the powder mixture 210 towards the web 204 at a main dispersion zone 228 (e.g., a dispersed powder cloud).

[0106] The system 200 includes multiple electrodes 230-240 (e.g., corona discharge electrodes, guiding electrodes, an electrode web or net, or the like) selectively positioned within the chamber 202. One electrode 230 can be positioned adjacent to the wall associated with the air input, and electrode 232 can be positioned further below the roller 214 or on the opposing side of the roller 214 from electrode 230. The electrodes 230, 232 are therefore horizontally spaced from each other within the chamber 202, and provide an electrostatic charge to the particles dispersed by the air stream. Although the electrodes 230, 232 can also provide a guiding function to the charged particles, in this area of the chamber 202, the guidance can be primarily provided by the air flow introduced into the chamber 202.

[0107] The electrodes 234-240 can be incrementally spaced / offset from each other, starting from the electrode 230, both horizontally and vertically to define a rightward arc in the direction of the web 204. The position of the electrodes 234-240 therefore moves further from the air supply intake and further right towards the web 204. The electrodes 234-240 can provide both an electrostatic charging function and a guiding function, depending on whether the particles within the zone 228 were previously charged. Out of the electrodes 234-240, the electrodes furthest from the roller 214 (e.g., electrodes 238, 240) can provide more of the guiding functionality, while electrodes closest to the roller 214 (e.g., electrodes 234, 236) can provide more of the charging functionality. However, the transition between charging and guiding can be gradual, and can be shared by one or more electrodes. Once the particles have been charged, the remaining downstream electrodes can guide the particles rightward towards the web 204. The web 204 includes a planar top surface 244 and a planar bottom surface 226. The web 204 enters the chamber 202 with the top surface 244 uncoated, and as the web travels in the direction 206, the electrodes 230-240 electrostatically charge the particles and guide them towards the top surface 244 to coat the web 204.30MEl\58073023.vlAttorney Docket No. 137174.00100

[0108] In some embodiments, the system 200 can include a plasma deflection shield 252 disposed within the chamber. The shield 252 limits the mobility of charged particles within the guiding zone and other areas of the chamber 202. The shield 252 can be disposed directly below the roller 214 and defines a substantially semicircular, complementary shape. The shield 252 prevents or reduces passage of powder particles towards the roller 214. In some embodiments, the system 200 can include a second shield formed either integrally or separately from the shield 252 to deflect and direct particles towards the web 204 without interfering with the airflow input into the system 200.

[0109] At the downstream end of the chamber 202, the system 200 includes an exhaust assembly 260 for removing any unused powder particles 262 and recycling such particles 262 for future use. The assembly 260 can include inwardly tapered duct walls 264 that extend towards an exhaust duct 266 for exhausting fugitive powder from the chamber 202 in direction 268. The exhausted powder can be collected and reused (e.g., reintroduced into the hopper 208) for coating of the web 204. In some embodiments, the system 200 can include a diffuser before the walls 264 (similar to diffuser 164 of the system 100 of FIG. 1). The system 200 therefore provides an efficient and effective way of dispersing a dry powder cloud towards the web 204 for electrostatic charging, and uses electrodes in a dual function manner to provide guidance to the electrostatically charged particles to direct such particles to the top surface 244 of the web 204. The combination of charging and guiding functionalities of the electrodes ensures a high uniformity of the coating at high mass flow rates of the powder.

[0110] As discussed herein, the system can be in a variety of configurations. For example, in some embodiments, the system 300 can be in the form of a dual-sided simultaneous coating configuration, as illustrated in FIG. 3. The system 300 includes a coating system 200a and a coating system 200b disposed on opposing sides of the web 204 (e.g., a mirrored layout). Each of systems 200a, 200b can be substantially similar to system 200 of FIG. 2. In the configuration of FIG. 3, the web 204 passes in-between the systems 200a, 200b such that the system 200a coats the top surface 244 and the system 200b simultaneously coats the bottom surface 246.

[0111] As another example, in some embodiments, the system 400 can be in the form of a dual-sided offset coating configuration, as illustrated in FIG. 4. The system 400 includes a coating system 200a and a coating system 200b disposed on opposing sides of31MEl\58073023.vlAttorney Docket No. 137174.00100 the web 204 and offset from each other in the machine direction. Each of systems 200a, 200b can be substantially similar to system 200 of FIG. 2. In the configuration of FIG. 4, the web 204 passes first through system 200a such that the bottom surface 246 of the web 204 is coated, and the web 204 continues to system 200b such that the top surface 244 of the web 204 is subsequently coated. Both surfaces 244, 246 of the web 204 can thereby be coated at different times.

[0112] As another example, in some embodiments, the system 500 can be in the form of a single-sided in series coating configuration, as illustrated in FIG. 5. The system 500 includes a coating system 100a and a coating system 100b disposed on the same side of the web 104 and offset from each other in the machine direction. Each of systems 100a, 100b can be substantially similar to system 100 of FIG. 1. In the configuration of FIG. 5, the web 104 passes first through system 100a such that the top surface 144 of the web 104 is coated with a first layer at a coated web section 148. The web 104 subsequently travels through system 100b where the coated web section 148 is further coated to achieve an updated coated web section 502 which has a thickness greater than the thickness of coated web section 148. Multiple systems can be positioned in series to achieve the desired final coated web thickness. In addition, multiple configurations for single and / or double-sided coating systems can be combined to achieve the desired coated web.

[0113] In some embodiments, the narrowing configuration of the electrodes within the coating chamber can be in a configuration other than an arc configuration. For example, FIG. 6 illustrates an exemplary electrostatic coating system 600 with electrodes 134-140 disposed along a narrowing configuration defined by a substantially linear line 602. In the narrowing configuration of FIG. 6, the distance of the adjacently positioned electrodes 134- 140 relative to the web 104 incrementally decreases such that the electrodes 134-140 are closer to the web 104 downstream than upstream along the moving web 104. Such narrowing configuration allows the electrodes 134-140 to charge the powder particles while simultaneously (or subsequently) guiding the particles towards the web 104. The narrowing configuration used in the exemplary systems discussed herein can therefore be in the arc configuration of FIG. 1, the linear line configuration of FIG. 6, or any other configuration in which the distance of the electrodes relative to the web is incrementally decreased in the downstream direction to provide guidance of the powder particles towards the surface of the web for even coating of the web. Other than the positioning of the electrodes 134-140, the system 600 can be substantially similar in structure and function to32MEl\58073023.vlAttorney Docket No. 137174.00100 the system 100. In some embodiments, the shield 150 can still define a curved extension even if the electrodes 134-140 are disposed in the linear line 602 configuration. In some embodiments, the shield 150 can define a substantially linear extension complementary to the linear line 602 of the electrodes 134-140.

[0114] In some embodiments, rather than an arc or linear narrowing configuration, the electrodes can be positioned the same distance from the web and the voltage applied to the electrodes can be varied to modify the electric field strength generated by the electrodes. In such embodiments, the electric field strength can gradually increase in the direction of movement of the web to guide the electrostatically charged electrodes towards the web surface. In some embodiments, the electric field strength can gradually decrease in the desired direction to guide the electrostatically charged electrodes towards the web surface. For example, the system would be substantially similar to the system 600 of FIG. 6, but the electrodes 134, 136, 138, 140 would be positioned an equal vertical distance from the web 104.

[0115] In some embodiments, the systems discussed herein can incorporate a variety of dispersion means. For example, the system 600 of FIG. 6 can incorporate air supply means that provide laminar or controlled turbulent air flow air flow to the chamber for uniformly dispersing the powder particles. After dispersion, the electrodes can charge and guide the powder particles towards the surface of the web.

[0116] In some embodiments, as illustrated in the system 700 of FIG. 7, the roller 114 can include a textured outer surface, brushes and / or bristles (e.g., mechanical means) to direct the powder particles into the coating chamber while simultaneously at least partially dispersing the powder particles. In some embodiments, the system 700 can include a guiding plate 702 defining a curvature substantially complementary to the curvature of the roller 114 to assist with directing the dispersed particles from an outlet 704 between the electrodes. Once partially dispersed, the electrodes can charge and guide the power particles towards the surface of the web. In some embodiments, the mechanical dispersion means can be in the form of one or more nozzles configured to direct and at least partially disperse the powder particles within the coating chamber.

[0117] In some embodiments, as illustrated in the system 800 of FIG. 8, the roller 114 can generally direct the power particles 802 along its surface to drop the particles 802 into the coating chamber with only the assistance of gravity. In particular, the system 800 does33MEl\58073023.vlAttorney Docket No. 137174.00100 not use an air flow or mechanical means for dispersing the particles 802, and instead relies on the particles 802 to disperse and they drop with the assistance of gravity towards the web. In such embodiments, the electrodes 804-814 can be positioned on opposing sides of the power particle stream to charge and guide the particles 802 towards the surface of the web. In some embodiments, the distance between the roller 114 and the web can be increased to allow for the particles 802 falling with the assistance of gravity to disperse sufficiently for charging and guiding of the particles 802 to occur before reaching the web surface.

[0118] Electrostatic Charging Assembly

[0119] FIG. 9 is a diagrammatic view of an exemplary electrostatic coating system 900 including an electrostatic charging assembly 902. Although discussed with respect to the system 900, it should be understood that the electrostatic charging assembly 902 could be incorporated into any of the systems discussed herein. In addition, although discussed as a “charging” assembly, it should be understood that the assembly can perform the charging function, the guiding function, or a combination of both.

[0120] The system 900 generally includes an air inlet 904 at the proximal end, including a fan or blower 906 for introducing and pushing air through a connecting duct 908, through a coating chamber 910, and out of an exhaust duct 912. In some embodiments, the system 900 can include an exhaust fan associated with the duct 912 to create a “pull” airflow, allowing for a balanced push / pull configuration that allows for selective balancing of pressure and airflow (see System Parameters below). The system 900 can include a tapering duct section 914 between the inlet 904 and the connecting duct 908.

[0121] The outlet of the connecting duct 908 leads directly into the inlet of the coating chamber 910. A hopper 916 or other mixing and / or storage container can be positioned above the coating chamber 910 and receives a powder particle mixture 918. A dispensing device 920 can be disposed at or near the outlet of the hopper 916, and dispenses powder particles 922 into the airflow stream within the coating chamber 910. The substrate or web 924 is introduced into the coating chamber 910 either at the proximal end of the coating chamber 910, or at an area of the coating chamber 910 substantially aligned with the dispensing device 910 (or electrode assembly 902). Rollers 926, 928, 930 can be used to move or support the web 924 through and out of the coating chamber 910.34MEl\58073023.vlAttorney Docket No. 137174.00100

[0122] Rather than being disposed within the coating chamber 910, the charging assembly 902 can be positioned on top of the coating chamber 910 such that the bottom of the charging assembly 902 is fluidly and aerodynamically open to the interior of the coating chamber 910. The charging assembly 902 includes a housing formed from a deflection shield 932 that prevents passage of charged particles 922 (e.g., charged ions) out of the charging assembly 902. The charging assembly 902 includes a first set of electrodes (i.e., charging electrodes 934) disposed in an array and surrounded on the sides by the deflection shield 932. In some embodiments, the charging electrodes 934 can be in the form of wires. The charging assembly 902 includes a second set of electrodes (i.e., guiding electrodes 936) disposed below the charging electrodes 934 and also surrounded on the sides by the deflection shield 932. In some embodiments, the guiding electrodes 936 can be in the form of rod electrodes, e.g., linear rod electrodes, a grid of rod electrodes, or the like. In this configuration, the guiding electrodes 936 separate the charging electrodes 934 from the interior of the coating chamber 910. As discussed herein, the powder particles 922 introduced into the coating chamber 910, are charged by the charging electrodes 934, and are subsequently guided downward toward the web 924 by the guiding electrodes 936. Powder particles 922 which do not coat the web can be reclaimed in a powder reclaim system 935 positioned below the web 924. The powder reclaim system 935 can feed powder continuously into a feed line with a reclaim mechanism 937 which conveys the powder to a central collection reservoir.

[0123] In some embodiments, the deflector shield 932 can be formed from five main surfaces, which define a volume of air where corona ions are formed. The five surfaces form a substantially rectangular box or housing, with the bottom surface removed. This removed surface leaves the defined volume open to the volume of the coating chamber 910. In the horizontal embodiment, electrodes 934 are positioned above guiding devices 936. The electrodes 934 can be charging electrodes and / or guiding electrodes. The ions formed by the electrodes 934 in the defined volume are filtered and made uniform by the guiding devices 936 as the ions flow from the defined volume into the coating chamber 910, towards the grounded web 924.

[0124] FIGS. 10A-D are detailed views of the charging assembly 902. The assembly 902 can include a housing formed by opposing walls 940, 941. The deflection shield 932 extends between the walls 940, 941 along the top surface, and the side surfaces, such that only the bottom surface is exposed to the coating chamber 910. Each of the charging35MEl\58073023.vlAttorney Docket No. 137174.00100 electrodes 934 can be releasably coupled to complementary sockets 942 secured to mounting blocks 943. In some embodiments, the charging electrodes 934 can be grouped in two or more electrode assemblies that can be simultaneously removed or added to the housing as needed. The charging electrodes 934 are therefore positioned in a spaced manner relative to each other, and extend substantially parallel to the walls 940, 941 of the housing.

[0125] The guiding electrodes 936 can be similarly coupled to complementary sockets 944 secured to mounting blocks 945. The mounting blocks 945 can be releasably secured to the walls 940, 941 of the housing. Guiding devices (e.g., guiding electrodes 936 or other guiding devices) are positioned in separate modules from the electrodes and are positioned such that the guiding devices are positioned below the electrodes 934. The guiding electrodes 936 act as guiding devices that, once the powder particles 922 are charged by the charging electrodes 934, guide the charged powder particles out of the charging assembly 902 and towards the web 924 surface.

[0126] In some embodiments, all electrodes of the system 900 can be configured to provide both a charging functionality and a guiding functionality. In some embodiments, some electrodes can be used exclusively to provide a charging functionality (e.g., electrodes 934), and some electrodes can be used exclusively to provide a guiding functionality (e.g., guiding electrodes 936). In some embodiments, additional guiding functionality can be provided by non-electrode elements, referred to herein as “guiding devices”. In some embodiments, the guiding devices can be in the form of, e.g., control rods, a grid, or the like (discussed below). In some embodiments, guiding devices can minimize ion discharge from a corona source and also filter corona ions so they flow uniformly from the charging electrodes to the grounded web.

[0127] Uniform ion flow contributes greatly to the uniformity of the coating. In some embodiments, the type of functionality of the charging electrodes can be dependent on a distance of the electrode position relative to the powder dispensing machine output (e.g., the hopper 916 output and / or the output at the dispensing apparatus 920), with charging electrodes closest to the output providing more of the charging functionality, electrodes furthest to the output providing more of the guiding functionality, and electrodes inbetween providing both the charging and guiding functionality. In some embodiments, the functionality of an element being an electrode or guiding device can be dependent on the36MEl\58073023.vlAttorney Docket No. 137174.00100 electrode geometry and operating condition, where electrodes can be traditional “corona discharge powder charging electrodes” and guiding devices can be any geometric and operative condition that minimizes ion discharge from corona discharge. The distinction of electrodes being traditional “corona discharge powder charging electrodes” does not inhibit them from the dual functionality of charging and guiding. In some embodiments, a combined use of the charging / guiding electrodes and guiding devices can be used to improve powder charging, deposition uniformity, and system reliability. The position and / or spacing of the electrodes and devices within the coating and / or electrostatic charging chamber is described herein as only exemplary, and it should be understood that alternative positions of the electrodes could be used, e.g., the electrode positioning described in International Patent Application No. PCT / US23 / 26276, filed on June 27, 2023, which is incorporated herein by reference in its entirety.

[0128] Particle Cloud Guiding: Overview

[0129] After the powder particles have been charged, the charged particle cloud continues to be conveyed by the air stream within the coating chamber. However, after charging, the powder particles now have an affinity to flow towards the grounded web due to the electrostatic charge on the particles and the presence of an electric field from the charging electrodes to the grounded substrate. The electric fields created by the charging electrodes (e.g., fine wires or points, typically less than about 0.2 mm in diameter) can create a non-uniform electric field to the grounded substrate.

[0130] A description of Peek’s law for purposes of corona onset principles and how they relate to design of the system is provided. The factors to determine if an electrode or guiding device will produce corona ions are the electrode’s radius, distance to the nearest equipotential surface (such as the grounded web), surface roughness, and (to a lesser extent) the density of air around the electrode. Each of these factors is used in Peek’s law, which defines the needed applied potential to generate corona discharge from the electrode. Peek’s law can be represented by Equation 1 below:where Vcrepresents the critical onset potential applied to the electrode; r represents the electrode radius; L represents the distance between the electrode and nearest equipotential conductor (typically ground); mvrepresents a roughness / irregularity factor for the electrodes (perfectly smooth electrodes have values of 1, while rough surface electrodes37MEl\58073023.vlAttorney Docket No. 137174.00100 are less than 1); g0represents the disruptive electric field (i.e., the electric field strength before air becomes conductive, typically 30-32 kV / cm in air); 8 = — - — is the air density PSATP factor relative to the air density at standard temperature and pressure (approximately 1 for most temperatures and pressures); and c represents an empirical constant whose value is 0.301 cml / 2.

[0131] To prevent the onset of corona discharge, Vc should be maximized for the electrode / conductor. Assuming a fixed distance relative to ground, this can be done by making the conductor surface smooth by polishing and removing sharp points, and / or by increasing the radius of the conductor. Conversely, to better enable the wire electrodes to produce charging ions, the electrodes should be small in radius, have some irregularities but not enough to disrupt the electric field, and be as close as possible to the grounded substrate.

[0132] As discussed, a uniform electric field can be used to improve deposition uniformity of the charged powder particles. The guiding principles to achieve electric field uniformity are highly dependent upon the geometry between the objects with applied potentials and a grounded substrate, such as the web. To illustrate this dependence, FIGS. 11A-C are provided, which show the electric field distribution of a side view of an exemplary point electrode located above a grounded plate. In particular, FIG. 11 A shows a single point electrode 980 with electric field line 982 distribution towards the grounded plate 984. FIG. 11B shows two point charges 986, 988 adjacently positioned to create electric field line 990, 992 distribution towards the grounded plate 984. FIG. 11C shows a single elongated point electrode 994 with electric field line 996 distribution towards the grounded plate 984. The point electrode can be thought of as a conductor with irregular geometry in the coating chamber, such as the wire electrode from a side view or a point electrode. Although the positive charge convention is adopted for illustration only, it should be understood that the system can be mirrored for the negative charge case.

[0133] With respect to FIG. 11A, the field lines 982 extending immediately underneath the point electrode 980 are relatively uniform. However, moving further to the left or right of the electrode 980 reveals that the field lines 982 begin to curve with decreasing uniformity. Thus, a positively charged powder particle encountering this electric field distribution would experience varying field strengths that could transport the powder in non-ideal directions or undesirably deposit the powder particle.38MEl\58073023.vlAttorney Docket No. 137174.00100

[0134] With respect to FIG. 11B, in order to increase the electric field uniformity, a second point electrode 988 can be added close to and in-line with the original point electrode 986 above the grounded plate 984. The electric field directly underneath the combined dual electrode system increases in uniformity as the individual charge’s electric fields overlap. By adding multiple irregular conductors in a specific orientation, the electric field uniformity can be greatly increased. The position of the point electrode 986, 988 relative to each other can be selected to ensure optimized uniformity in the resulting electric fields.

[0135] With respect to FIG. 11C, rather than multiple point electrodes, the electrode 994 can be elongated along at least a portion of the grounded plate 984. In some embodiments, multiple charges 994 can be positioned adjacent to each other (similarly to FIG. 1 IB). The electric field line 996 uniformity underneath the elongated point electrode 994 is significantly more uniform than the original point electrode 980 system. Now, a positively charged powder particle in this zone would experience a uniform electric field of constant strength directing it towards the grounded plate 984. This principle can be used in the electrode design of the disclosed systems to precisely influence the charged powder particle path in three dimensional space. Such electric fields can be used to direct the powder particles towards one location, e.g., the grounded web, or repelling the powder particles from another location, e.g., the chamber side walls, depending upon the designed form factor of the object, such as guiding electrodes or guiding devices, and the applied potential to said object.

[0136] Due to the electric field non-uniformities of corona generating wire and point electrodes as described, guiding electrodes with specific geometries and configurations can be utilized to improve the electric field uniformity which drives the charged particles in a more controlled and uniform manner towards the substrate. The guiding electrodes and devices are referred to herein as the “guiding system” or “guiding device(s)”. The guiding system produces an electric field of varying strength and geometry, which effectively creates a directed potential gradient for the charged powder particles to follow to a desired location, e.g., towards the web. In some embodiments, the guiding wire electrodes produce plasma zones (e.g., corona discharge, or the like) in addition to the electric field, which effectively produce a zone of charged ions, creating an electric field from the ion space charge which supports guiding of the charged powder particles in the desired location, e.g., towards the web. In some embodiments, the guiding system can function to reduce the39MEl\58073023.vlAttorney Docket No. 137174.00100 magnitude of the powder velocity vector in the machine direction by imparting a vector of electric force on the charged particle, enabling the electrodynamic forces to be the dominant force during deposition. The guiding system can be placed in strategic locations relative to the general charged powder particle flow such that the flow of the charged powder particle cloud is further directed towards the web.

[0137] Particle Cloud. Guiding: Device and. Functionality

[0138] In some embodiments, the guiding devices can be arranged to shield the charging electrodes from the powder particles. This works to smooth the ion production from the charging electrodes to promote a uniform stream of corona ions towards the particle charging zone and web. Such arrangement and functionality improves deposition uniformity and system reliability as a more uniform charge distribution on the particles can be obtained. In some embodiments, the horizontal spacing in the machine direction between guiding devices can be used to control the number of ions and the electric field uniformity in the powder particle charging zone, with further spacing leading to a higher number of ions and a less uniform electric field.

[0139] For the ESD application, the spacing can be at least 1 cm and generally less than 20 cm. In some embodiments, the spacing can be about, e.g., 1-20 cm inclusive, 1-19 cm inclusive, 1-18 cm inclusive, 1-17 cm inclusive, 1-16 cm inclusive, 1-15 cm inclusive, 1- 14 cm inclusive, 1-13 cm inclusive, 1-12 cm inclusive, 1-11 cm inclusive, 1-10 cm inclusive, 1-9 cm inclusive, 1-8 cm inclusive, 1-7 cm inclusive, 1-6 cm inclusive, 1-5 cm inclusive, 1-4 cm inclusive, 1-3 cm inclusive, 1-2 cm inclusive, 2-20 cm inclusive, 3-20 cm inclusive, 4-20 cm inclusive, 5-20 cm inclusive, 6-20 cm inclusive, 7-20 cm inclusive, 8- 20 cm inclusive, 9-20 cm inclusive, 10-20 cm inclusive, 11-20 cm inclusive, 12-20 cm inclusive, 13-20 cm inclusive, 14-20 cm inclusive, 15-20 cm inclusive, 16-20 cm inclusive, 17-20 cm inclusive, 18-20 cm inclusive, 19-20 cm inclusive, 2-18 cm inclusive, 5-15 cm inclusive, 8-12 cm inclusive, 2-9 cm inclusive, 3-8 cm inclusive, 4-7 cm inclusive, 1 cm, 2 cm, 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 11 cm, 12 cm, 13 cm, 14 cm, 15 cm, 16 cm, 17 cm, 18 cm, 19 cm, 20 cm, or the like. In some embodiments, the guiding devices can be connected to ground via a high resistance circuit which can also be used to control the number of ions and the electric field uniformity in the powder particle charging zone where higher resistance leads to more ions and electric field uniformity. Due to the resistance to ground, corona ions can build up on the guiding electrodes and a potential to40MEl\58073023.vlAttorney Docket No. 137174.00100 ground will be realized. Once the guiding system is “saturated” with corona ions, the remaining ions can travel past the guiding system and into the “powder charging zone” with a more uniform spatial distribution compared to a charging wire electrode alone.

[0140] Another means to control the potential at the guiding devices can be to directly apply a bias potential using a power supply . In some embodiments, the vertical distance between charging electrodes and guiding devices can be used to increase or decrease the number of ions in the particle charging zone, with a closer distance yielding more ions. In some embodiments, the horizontal distance between charging electrodes can be set to provide a uniform number of ions per charging area in the machine direction, with further spacing leading to less uniformity. As for the charging electrodes to guiding devices alignment, this can be set to provide symmetry from the machine side view to promote ion and consequently, deposition uniformity.

[0141] In general, the electrodes and guiding devices, particularly charging electrodes, should maintain a minimum spacing between other conductive elements, such as other electrodes or the grounded web, to minimize / eliminate electrical breakdown in the form of arcing (e.g., based on a function of the applied voltage to the wire). Typically, for voltages used in the ESD application, the spacing can be at least about 1 cm. In some embodiments, the wire electrodes can be, e.g., less than about 45 cm from each other and / or from the web, e.g., less than about 30 cm from each other and / or from the web, or the like. In some embodiments, the spacing can be about, e.g., 1-45 cm inclusive, 1-40 cm inclusive, 1-35 cm inclusive, 1-30 cm inclusive, 1-25 cm inclusive, 1-20 cm inclusive, 1-15 cm inclusive, 1-10 cm inclusive, 1-5 cm inclusive, , 5-45 cm inclusive, 10-45 cm inclusive, 15-45 cm inclusive, 20-45 cm inclusive, 25-45 cm inclusive, 30-45 cm inclusive, 35-45 cm inclusive, 40-45 cm inclusive, 5-40 cm inclusive, 10-35 cm inclusive, 15-30 cm inclusive, 20-25 cm inclusive, 1 cm, 5 cm, 10 cm, 15 cm, 20 cm, 25 cm, 30 cm, 35 cm, 40 cm, 45 cm, or the like. In some embodiments, the guiding system can be in the form of a grid.

[0142] In some embodiments, the guiding system can include polished rods of at least 0.01 in diameter spaced at regular intervals of less than 45 cm from each other. In some embodiments the guiding system can be polished, rounded plates spaced at intervals less than 45 cm from each other. In some embodiments the guiding system can be a rounded grid or mesh plate covering up to the entire deflection shield surface.41MEl\58073023.vlAttorney Docket No. 137174.00100

[0143] In some embodiments, the guiding system and charging electrodes can be arranged further from the web than the powder dispensing mechanism, removed from the bulk airstream. In some embodiments, the guiding system and charging electrodes can be a similar distance from the web as the powder dispensing mechanism. In some embodiments, the guiding system and charging electrodes can be closer to the web than the powder dispensing system, situated in the bulk airstream.

[0144] Particle Cloud Guiding: Deflection Shield

[0145] The system can include a deflection shield within the coating chamber to limit the mobility of the ionized air out of the “guiding zone”, e.g., the zone in which the guiding system directs the powder towards the web. In some embodiments, the deflection shield can be fabricated using the electric fields from guiding devices, the plasma from charging electrodes, and the ion barrier from insulative objects, which will concentrate ions similar to the guiding electrode plasma shield, or a combination thereof of all three methods. The shield can be used to isolate the charged powder path from attracting towards the dispensing roller or alternative mechanism. When charging is first occurring, the powders are highly likely to be closer to the dispensing machine than the web, influencing the flow direction. As such, the shield can be used to prevent attraction of the charged powder path towards the dispensing roller. In some embodiments, the dispensing roller can be fully insulated to eliminate risks of powder coating onto the roller or any other conductive surfaces in the system. This can provide additional protection over the deflection shield. This deflection shield can be incorporated into any of the systems discussed herein.

[0146] Particle Cloud Guiding: Narrowing Configuration

[0147] In some embodiments, the guiding electrodes can be disposed in a downward arc or downward linear direction towards the web (see, e.g., FIG. 1), guiding / conditioning the powder path. The downward direction of the electrodes is referred to herein as a “narrowing configuration”, and is intended to describe the gradually narrower or reduced distance between the electrodes and the surface of the web in the downstream direction to direct / guide the powder path towards the surface of the web. Although an arc and linear configuration are illustrated, it should be understood that alternative narrowing configurations / positions of the electrodes are also envisioned.

[0148] In some embodiments, the guiding electrodes can be disposed in a rightward or leftward arc towards the web (see, e.g., FIG. 2), guiding / conditioning the powder path. In42MEl\58073023.vlAttorney Docket No. 137174.00100 some embodiments, the effective electric field created by a narrowing configuration at an equal and fixed voltage for each electrode can be created by keeping the electrodes at an equal distance and changing the applied voltage to each electrode since the electric field strength is a function of distance to “ground” and the applied voltage. In such embodiments, the electric field strength can be incrementally increased at adjacently positioned electrodes using an increase in the applied voltage to gradually guide the charged powder particles towards the web. As noted herein, the position and / or spacing of the electrodes within the coating chamber is described herein as only exemplary, and it should be understood that alternative positions of the electrodes could be used, e.g., the electrode positioning described in International Patent Application No. PCT / US23 / 26276, filed on June 27, 2023, which is incorporated herein by reference in its entirety. In general, the charging electrodes should maintain a minimum spacing between other conductive elements, such as other electrodes or the grounded web, to minimize / eliminate electrical breakdown in the form of arcing (e.g., based on a function of the applied voltage to the wire) and electric field deflection. Typically, for voltages used in the ESD application, the spacing can be at least about 1 cm. In some embodiments, the electrodes can be, e.g., less than about 45 cm from each other and / or from the web, e.g., less than about 30 cm from each other and / or from the web, or the like.

[0149] Particle Cloud Guiding: Increasing Potential Configuration

[0150] In some embodiments, as an alternative or in conjunction with the narrowing configuration, the operating voltage on each guiding electrode and device can be set to create a varying potential in the machine direction, such as from left to right (see, e.g., FIG 1), and referred to herein as the "increasing potential configuration”. As in the narrowing configuration, the increasing potential configuration is intended to direct / guide the powder path towards the direction of the web. Guidance occurs because increasing the potential of an electrode at a fixed distance to the web will increase the electric field strength from that electrode. Subsequent electrodes after the leading electrodes with higher applied potentials result in an increasing electric field strength resulting in an increased electric force directing charged powder particles to the web. In some embodiments, the potential configuration can be set such that the potential of each electrode decreases in the machine direction, or in a “decreasing potential configuration” to direct the charged powder particles early in the coating chamber and gradually reduces as the number of particles in the coating chamber reduces in the machine direction. Although an increasing and decreasing potential43MEl\58073023.vlAttorney Docket No. 137174.00100 configuration is described, it should be understood that alternative potential configurations of the electrodes are also envisioned.

[0151] Particle Cloud Guiding Operating Considerations

[0152] In order to enable the charging and guiding mechanism described, it is highly beneficial to enable the Coulombic forces during deposition of the dry powder. These electrical forces are in competition with other forces in the coating system, e.g., gravitational forces, drag forces, and any momentum the powder particles have. Consequently, in some embodiments, the particle velocity magnitude and turbulence can be controlled to present the dry powder for charging and guidance; thus, enabling the electrostatic forces to direct deposition. The airflow, dispensing, and dispersion can be set such that the particle velocity magnitude be about, e.g., 25-750 fpm inclusive, 25-700 fpm inclusive, 25-650 fpm inclusive, 25-600 fpm inclusive, 25-550 fpm inclusive, 25-500 fpm inclusive, 25-450 fpm inclusive, 25-400 fpm inclusive, 25-350 fpm inclusive, 25-300 fpm inclusive, 25-250 fpm inclusive, 25-200 fpm inclusive, 25-150 fpm inclusive, 25-100 fpm inclusive, 25-50 fpm inclusive, 50-750 fpm inclusive, 100-750 fpm inclusive, 150-750 fpm inclusive, 200-750 fpm inclusive, 250-750 fpm inclusive, 300-750 fpm inclusive, 350-750 fpm inclusive, 400-750 fpm inclusive, 450-750 fpm inclusive, 500-750 fpm inclusive, 550- 750 fpm inclusive, 600-750 fpm inclusive, 650-750 fpm inclusive, 700-750 fpm inclusive, 150-650 fpm inclusive, 300-500 fpm inclusive, 25 fpm, 50 fpm, 100 fpm, 150 fpm, 200 fpm, 250 fpm, 300 fpm, 350 fpm, 400 fpm, 450 fpm, 500 fpm, 550 fpm, 600 fpm, 650 fpm, 700 fpm, 750 fpm, or the like, in the coating chamber. By limiting the powder speed and controlling the surrounding turbulence, the charging assembly can create the dominant force vector in achieving the target uniformity and transfer efficiency for the system.

[0153] Varying Powder Charging

[0154] In some embodiments, the potential on each electrode can be set to create a non- uniform distribution of ions. This can be used to selectively charge different regions of the powder path within the coating chamber to different degrees, e.g., providing more ions, via increased electrode voltage, to densely packed regions of the powder cloud to increase each particle’s charge. Having this functionality improves transfer efficiency and deposition uniformity.

[0155] For the ESD application, charging electrode potentials can be set to provide electric field strengths between about, e.g., 0.1-25 kV / cm inclusive, 0.5-25 kV / cm44MEl\58073023.vlAttorney Docket No. 137174.00100 inclusive, 1-25 kV / cm inclusive, 5-25 kV / cm inclusive, 10-25 kV / cm inclusive, 15-25 kV / cm inclusive, 20-25 kV / cm inclusive, 0.1-20 kV / cm inclusive, 0.1-15 kV / cm inclusive, 0.1-10 kV / cm inclusive, 0.1-5 kV / cm inclusive, 0.1-1 kV / cm inclusive, 0.1-0.5 kV / cm inclusive, 0.1 kV / cm, 0.5 kV / cm, 1 kV / cm, 5 kV / cm, 10 kV / cm, 15 kV / cm, 20 kV / cm, 25 kV / cm, or the like. In some embodiments, the guiding devices can be used to generate non- uniform regions of ions. The horizontal spacing in the machine direction between each guiding device, the resistance of the guiding device’s circuit, and / or the charging electrode to guiding device spacing can all be varied to control the amount of ions in a given region, achieving the desired functionality. Though these conditions to provide a higher number of ions for denser regions is described, other operating arrangements could be used to achieve the desired influence on the powder cloud.

[0156] System Parameters

[0157] A variety of operational parameters, settings and / or configurations for the electrostatic coating systems discussed herein can be designed, monitored, and controlled via one or more sensors disposed within the system. As an example, one or more coating chamber configurations and components can be designed and selected based on the variations discussed herein. As another example, one or more sensors within or around the coating chamber can be used to detect various conditions within the system, and transmit the detected conditions to a central controller. The central controller can use the detected conditions to vary one or more operating parameters of the system to optimize the overall operation of the system. As such, a control feedback loop can be incorporated into any of the systems discussed here. It should be understood that one or more of the operating parameters and designs / configurations can be selected to optimize powder particle dispersion, settling and coating of the web.

[0158] One such operating parameter involves airflow conditions within the coating chamber and how such airflow conditions affect the powder particles during dispersion, charging, and guidance onto the web surface. Because the powder particles used in the systems are very small (e.g., about 5-20 micron diameter, or the like), the path that the particles follow from the feeder, through the dispersion zone, and to the web surface is highly influenced by even the most subtle velocity variations, in both magnitude and direction. As discussed herein, “dispersion zone” refers to the area within the coating chamber in which the powder particles disperse after introduction into the coating chamber.45MEl\58073023.vlAttorney Docket No. 137174.00100It is thus critical to control the velocity carefully as the air flow approaches and travels through the main dispersion zone of the coating chamber. This can be accomplished through detailed attention to fluid dynamic parameters and influences (e.g., via preset operating conditions, sensors to monitor and vary the operating conditions, combinations thereof, or the like). The operating parameters and influences are discussed below.

[0159] Fans: Number and. Arrangement

[0160] As discussed herein, the systems generally include an air supply system at the inlet of the coating chamber, and generally include an air exhaust system at the outlet of the coating chamber. In some embodiments, the system can use highly laminar or controlled turbulence, uniform air as a down-web dispersion mechanism for a dense dispensed powder stream into an electrostatic charging zone. In such embodiments, the airflow is used to disperse the powder particles and (in some instances) break apart clumps of powder particles dropping into the coating chamber. The air supply assembly or system can be any type known in the industry, e.g., a centrifugal or axial fan, cyclone vacuum, a positive pressure blower, a negative pressure blower, combinations thereof, or the like. The air supply system can provide filtered and diffused air into the coating chamber.

[0161] In some embodiments, as illustrated in FIG. 13, the air source 1000 can be a “push” system, with the air supply 1000 at the inlet being pushed into the coating chamber 1002, resulting in positive pressure within the coating zone. As the powder particles 1004 are fed or dropped into the coating chamber 1002, the air flow from the air source 1000 breaks apart and / or disperses the powder particles 1004 within the coating chamber 1002 and onto the surface of the web 1006.

[0162] In some embodiments, as illustrated in FIG. 14, an opposite configuration of the air flow can be used in the system. In particular, the system of FIG. 14 illustrates a “pull” system, with the air supply 1010 at the outlet of the coating chamber 1002. Having the air supply 1010 at the outlet of the coating chamber 1002 draws air flow through the coating chamber 1002 under negative pressure, instead of pushing air through the coating chamber 1002. Such pulling system can still break apart and / or disperse the powder particles 1004 as they are introduced into the coating chamber 1002. In some embodiments, ductwork from the air supply 1010 can include a cyclone 1012 section below the air supply 1010 to collect powder particles in a collection housing 1014 for reuse in subsequent coating46MEl\58073023.vlAttorney Docket No. 137174.00100 applications. In some embodiments, additional ductwork can lead from the air supply 1010 to a dust filter 1016 for filtering the air passing out of the system.

[0163] In some embodiments, as illustrated in FIG. 15, the air supply devices 1000, 1010 can be incorporated at both the inlet and outlet of the coating chamber 1002. Such configuration can result in a “balanced draft” system, where two or more fans and / or blowers work together to provide the desired flow rate through the coating chamber 1002. With both a push and pull configuration, the ability to maintain a specific pressure set point balance in the coating zone is provided. For example, in this configuration, one fan can be controlled to provide the desired flow rate (via a velocity measurement from a sensor disposed within the coating chamber 1002), while the other fan / blower is controlled to maintain the desired pressure inside the dispersion chamber 1002.

[0164] Coating Chamber Configurations

[0165] In some embodiments, the configuration (e.g., cross-section) of the inlet and / or outlet sections of the coating chamber can be varied to affect the air flow through the coating chamber. In some embodiments, as illustrated in FIGS. 14 and 15, the inlet section 1001 to the dispersion zone can define a smooth contracting bell-mouth configuration / cross-section. In some embodiments, an inlet filter 1005 can be disposed at the proximal end of the inlet section 1001. In some embodiments, one or more settling screens 1003 can be disposed at the distal end of the inlet section 1001 (e.g., immediately adjacent to the coating chamber 1002 to generate a more uniform velocity profile. The settling screens 1003 can therefore be used for velocity and / or turbulence control of the air introduced into the coating chamber 1002.

[0166] Such bell-mouth configuration can work well in the pull version of the system, operating at a negative pressure in the main dispersion zone. For the push or the balanced draft systems, a fan or blower can be situated at or near the inlet to the system (upstream of the inlet section 1001), and thus a carefully designed expansion section 1007 can be used to reach the full cross-sectional area of the main dispersion zone (see, e.g., FIG. 16). The expansion section 1007 can be smallest in cross-section at or near the air supply system 1000, and can gradually taper and expand up to the cross-sectional area complementary to the coating chamber 1002. This expansion can be based on fluid dynamic practice with a gradual expansion angle of about, e.g., 5-9° inclusive, 6-8° inclusive, 5°, 6°, 7°, 8°, 9°, or the like, in order to avoid flow separation.47MEl\58073023.vlAttorney Docket No. 137174.00100

[0167] However, for some geometries, this can create a very long inlet section 1007 that may not be suitable for all equipment packaging and / or dimensional constraints. For limited environment constraints, the inlet section can be formed from one or more elbows with a steeper expansion angle and with guide vanes to maintain flow control. For example, FIG. 24 provides an inlet section arrangement that includes a gradual expansion section 1100 with an angle of about, e.g., e.g., 5-9° inclusive, 6-8° inclusive, 5°, 6°, 7°, 8°, 9°, or the like, to increase the cross-sectional area. The expansion section 1100 connects to a first 90° elbow 1102 which, in turn, connects to a second 90° elbow 1104, both of which can include internal guide vanes. Adjacent to the elbow 1104, the duct arrangement can include a filter 1106 (e.g., a HEPA filter, or the like), which connects to a smooth, contracting bellmouth section 1108. Airflow from the fan enters the expansion section 1100 at its inlet 1110, passes through the ducting arrangement, and exists through the outlet 1112 which is coupled to the coating chamber inlet. Such arrangement reduces footprint requirements for the inlet section while maintaining the desired air flow entering the coating chamber. This arrangement can also incorporate an inlet air filter to avoid any contaminants entering the system (such as the filter of FIGS. 14 and 15). The additional pressure loss provided by the filter can further smooth out the velocity profile at the dispersion zone inlet (i.e., the inlet of the coating chamber) by insulating the system from variations of non-uniformities (either spatial or temporal) in fan outlet conditions or upstream flow devices / vanes.

[0168] Coating Chamber Conditions: Velocity Magnitude and. Uniformity

[0169] The air velocity at the point of powder particle introduction into the coating chamber and through the dispersion zone within the coating chamber can be critical for conveying and diluting the concentrated stream of powder to allow electrostatic charging of individual particles which then collect on the web. In some embodiments, the system can use an air velocity of about, e.g., 25-750 feet per minute (fpm) inclusive, 25-700 fpm inclusive, 25-650 fpm inclusive, 25-600 fpm inclusive, 25-550 fpm inclusive, 25-500 fpm inclusive, 25-450 fpm inclusive, 25-400 fpm inclusive, 25-350 fpm inclusive, 25-300 fpm inclusive, 25-250 fpm inclusive, 25-200 fpm inclusive, 25-150 fpm inclusive, 25-100 fpm inclusive, 25-50 fpm inclusive, 50-750 fpm inclusive, 100-750 fpm inclusive, 150-750 fpm inclusive, 200-750 fpm inclusive, 250-750 fpm inclusive, 300-750 fpm inclusive, 350-750 fpm inclusive, 400-750 fpm inclusive, 450-750 fpm inclusive, 500-750 fpm inclusive, 550- 750 fpm inclusive, 600-750 fpm inclusive, 650-750 fpm inclusive, 700-750 fpm inclusive, 100-600 fpm inclusive, 200-500 fpm inclusive, 300-400 fpm inclusive, 50-300 fpm48MEl\58073023.vlAttorney Docket No. 137174.00100 inclusive, 50-350 fpm inclusive, 50-400 fpm inclusive, 50-450 fpm inclusive, 50-500 fpm inclusive, 50-250 fpm inclusive, 50-200 fpm inclusive, 50-150 fpm inclusive, 50-100 fpm inclusive, 100-300 fpm inclusive, 150-300 fpm inclusive, 200-300 fpm inclusive, 250-300 fpm inclusive, 100-250 fpm inclusive, 150-200 fpm inclusive, 100-200 fpm inclusive, 25 fpm, 50 fpm, 100 fpm, 150 fpm, 200 fpm, 250 fpm, 300 fpm, 350 fpm, 400 fpm, 450 fpm, 500 fpm, 550 fpm, 600 fpm, 650 fpm, 700 fpm, 750 fpm, or the like, to smoothly accelerate the powder.

[0170] These values were determined based on extensive laboratory testing that considered the density, drag coefficient, and initial velocity of the powder particles as they leave the roller and pass through the initial dispersion zone within the coating chamber. The specified velocity range takes into consideration trade-offs between the powder deposition quality and the ability of the air to adequately transport the powder from the injection point onto the web. Lower velocities produce a smoother quality deposition pattern, but can result in greater fall-out of powder particles upstream of the web. In contrast, while higher velocities transport the powder particles more efficiently to the web, such higher velocities can produce a coarser deposition pattern. As such, the specified ranges produce optimal results in both smooth quality deposition patterns and transport of powder particles along the web surface.

[0171] In some embodiments, for horizontal orientation of the web, a velocity range of about, e.g., 100-200 fpm inclusive, 100-175 fpm inclusive, 100-150 fpm inclusive, 100- 125 fpm inclusive, 125-200 fpm inclusive, 150-200 fpm inclusive, 175-200 fpm inclusive, 125-175 fpm inclusive, 100 fpm, 125 fpm, 150 fpm, 175 fpm, 200 fpm, or the like, provided optimal results for deposition pattern quality and transport of particles along the web surface based on laboratory experimentation. In vertical web orientations, a slightly lower air velocity range (about e.g., 15-200 fpm inclusive, 15-175 fpm inclusive, 15-150 fpm inclusive, 15-125 fpm inclusive, 15-100 fpm inclusive, 15-75 fpm inclusive, 15-50 fpm inclusive, 15-25 fpm inclusive, 25-200 fpm inclusive, 50-200 fpm inclusive, 75-200 fpm inclusive, 100-200 fpm inclusive, 125-200 fpm inclusive, 150-200 fpm inclusive, 175-200 fpm inclusive, 50-175 fpm inclusive, 50-125 fpm inclusive, 50-100 fpm inclusive, 50-75 fpm inclusive, 75-150 fpm inclusive, 100-150 fpm inclusive, 125-150 fpm inclusive, 75- 125 fpm inclusive, 15 fpm, 25 fpm, 50 fpm, 75 fpm, 100 fpm, 125 fpm, 150 fpm, 175 fpm, 200 fpm, or the like) can be more effective since the powder particles will also accelerate due to gravity.49MEl\58073023.vlAttorney Docket No. 137174.00100

[0172] Coating Chamber Conditions: Pressure Control, In-leakage, and ParticulateBehavior Control

[0173] In some embodiments, control of the static pressure in the main dispersion zone can be of critical importance for powder particle dispersion and control. This determination was made based on prototype development and extensive research tests. Because of the small size of the powder particles, even subtle variations to local velocities can impact particle transport behavior. In particular, any irregular wafting of flow either cross-web or down-web can cause powder uniformity imbalances on the surface coating of the web. Inleakage, where outside air is drawn into the coating chamber (e.g., tunnel), or out-leakage, where flow exits the coating chamber, can occur through small gaps (such as the web infeed / outfeed slots and the powder feed system connection to the dispersion zone). A “pull” system is generally susceptible to in-leakage, while a “push” system is generally susceptible to out-leakage (see, e.g., arrows in FIG. 13 for push system showing out- leakage). Any such leakage can result in detrimental velocity disturbances, off-axial particle flow vectors, and swirling / rotational flow regions that can result in non-uniform powder collection on the web. As such, the push or pull configurations of the system can be less effective than the balanced draft configuration of the system, which provides a highly uniform, well-controlled velocity through the dispersion zone.

[0174] Balanced draft operation uses fans / blowers at both the inlet and outlet sections of the coating chamber such that the dispersion zone static pressure within the coating chamber (relative to ambient pressure external to the system) can be maintained at a specified set point. In some embodiments, the fans can be controlled with a proper control logic and feedback (e.g., one or more sensors disposed along the coating chamber), such that a nearly zero, slightly negative static pressure exists within the main dispersion zone of the coating chamber. In some embodiments, the static pressure can be about, e.g., -0.001 to -0.020 inches of water inclusive, -0.001 to -0.019 inches of water inclusive, -0.001 to - 0.018 inches of water inclusive, -0.001 to -0.017 inches of water inclusive, -0.001 to -0.016 inches of water inclusive, -0.001 to -0.015 inches of water inclusive, -0.001 to -0.014 inches of water inclusive, -0.001 to -0.013 inches of water inclusive, -0.001 to -0.012 inches of water inclusive, -0.001 to -0.011 inches of water inclusive, -0.001 to -0.01 inches of water inclusive, -0.001 to -0.009 inches of water inclusive, -0.001 to -0.008 inches of water inclusive, -0.001 to -0.007 inches of water inclusive, -0.001 to -0.006 inches of water inclusive, -0.001 to -0.005 inches of water inclusive, -0.001 to -0.004 inches of water50MEl\58073023.vlAttorney Docket No. 137174.00100 inclusive, -0.001 to -0.003 inches of water inclusive, -0.001 to -0.002 inches of water inclusive, -0.002 to -0.020 inches of water inclusive, -0.003 to -0.020 inches of water inclusive, -0.004 to -0.020 inches of water inclusive, -0.005 to -0.020 inches of water inclusive, -0.006 to -0.020 inches of water inclusive, -0.007 to -0.020 inches of water inclusive, -0.008 to -0.020 inches of water inclusive, -0.009 to -0.020 inches of water inclusive, -0.01 to -0.020 inches of water inclusive, -0.011 to -0.020 inches of water inclusive, -0.012 to -0.020 inches of water inclusive, -0.013 to -0.020 inches of water inclusive, -0.014 to -0.020 inches of water inclusive, -0.015 to -0.020 inches of water inclusive, -0.016 to -0.020 inches of water inclusive, -0.017 to -0.020 inches of water inclusive, -0.018 to -0.020 inches of water inclusive, -0.019 to -0.020 inches of water inclusive, -0.005 to -0.015 inches of water inclusive, -0.005 to -0.01 inches of water inclusive, -0.002 to -0.005 inches of water inclusive, -0.003 to -0.005 inches of water inclusive, -0.004 to -0.005 inches of water inclusive, -0.002 to -0.004 inches of water inclusive, -0.001 inches of water, -0.002 inches of water, -0.003 inches of water, -0.004 inches of water, -0.005 inches of water, -0.006 inches of water, -0.007 inches of water, - 0.008 inches of water, -0.009 inches of water, -0.01 inches of water, -0.011 inches of water,-0.012 inches of water, -0.013 inches of water, -0.014 inches of water, -0.015 inches of water, -0.016 inches of water, -0.017 inches of water, -0.018 inches of water, -0.019 inches of water, -0.02 inches of water, or the like, (compared to the external of the coater system) can be used.

[0175] By keeping the static pressure just slightly negative, there is no out-leakage, and only a minimum amount of in-leakage occurs, to adversely influence the flow vectors of the air and powder in the dispersion zone. The control system can be used to automatically adjusts the fans, in real-time, using feedback from static pressure measurements taken at strategically located pressure taps 1009 (e.g., sensors) in the sidewalls of the dispersion zone of the coating chamber. The pressure taps 1009 can be located downstream of and as close as possible to the particle injection location (see, e.g., FIG. 15). By controlling the static pressure to just slightly negative at this location, optimal performance and uniformity of powder coating on the web can be achieved.

[0176] Coating Chamber Conditions: Turbulence

[0177] As discussed herein, in some embodiments, a turbulence controlling structure can be disposed upstream of the coating chamber and configured to reduce turbulence in51MEl\58073023.vlAttorney Docket No. 137174.00100 the air flow to achieve laminar or controlled turbulence air flow prior to entry of the powder into the coating chamber. In some embodiments, the turbulence control structure can include an array of openings through which the air flow passes. In some embodiments, the openings of the array can each define a honeycomb configuration. In some embodiments, the honeycomb configuration can be combined with one or more thin structures or screens with an array of openings through which the air flow passes. In some embodiments, these screens can be defined as settling screens (see, e.g., settling screens 1003 of FIGS. 14 and 15). In some embodiments, these thin structures can be perforated plates, with specified percent open area and hole size to control downstream flow patterns and size of turbulent eddies. Generally, the open area can be in the range of about, e.g., 1-85% open inclusive, 1-75% open inclusive, 1-65% open inclusive, 1-55% open inclusive, 1-45% open inclusive, 1-35% open inclusive, 1-30% open inclusive, 1-25% open inclusive, 1-20% open inclusive, 1-10% open inclusive, 20-35% open inclusive, 35-55% open inclusive, 35-75% open inclusive, 35-85% open inclusive, 55-75% open inclusive, 1% open, 5% open, 10% open, 20% open, 30% open, 35% open, 45% open, 55% open, 65% open, 75% open, 85% open, or the like.

[0178] Coating Chamber Conditions: Angle of Inclination of Flow

[0179] In some embodiments, a slight angle of the airflow away from the web at the inlet can be used, instead of airflow traveling parallel to the web (see, e.g., FIGS. 17-19). Such configuration is illustrated in FIG. 17, showing a coating chamber 1020 with a dispensing roller 1022 introducing powder particles 1024 into the coating chamber 1020 for dispersion onto the web 1026. Vanes or baffles 1028 at the inlet of the coating chamber 1020 can be used to change the angle of the input airflow introduced into the coating chamber 1020.

[0180] For a horizontally oriented system, the angle of inclination is an upwards angle, i.e., away from the web 1026 and towards the ceiling of the dispersion zone of the coating chamber 1020. For a vertically oriented system, the angle of inclination is a downward angle, towards the web and air exhaust.(see, e.g., system 200). In some embodiments, an angle in the range of about, e.g., 5-50° inclusive, 5-45° inclusive, 4-40° inclusive, 5-35° inclusive, 5-30° inclusive, 5-25° inclusive, 5-20° inclusive, 5-15° inclusive, 5-10° inclusive, 10-50° inclusive, 15-50° inclusive, 20-50° inclusive, 25-50° inclusive, 30-50° inclusive, 35-50° inclusive, 40-50° inclusive, 45-50° inclusive, 10-45° inclusive, 15-40°52MEl\58073023.vlAttorney Docket No. 137174.00100 inclusive, 15-35° inclusive, 15-30° inclusive, 15-25° inclusive, 15-20° inclusive, 20-40° inclusive, 25-40° inclusive, 30-40° inclusive, 35-40° inclusive, 20-35° inclusive, 25-30° inclusive, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, or the like, relative to horizontal can be used based on experimental testing optimal conditions. Such angled airflow provides an additional vertical vector / lifting force on the powder particles for the horizontal system configuration and a sideward force on the powder particles for the vertical system configuration, allowing the powder particles to better disperse into the flow stream and encourages attachment of the particles to the moving web. In some embodiments, the change in flow direction from the initial incoming direction can be accomplished with small, angled baffles or vanes 1028 in the flow stream just upstream of the particulate inlet. In some embodiments, such change in flow direction can be achieved with a fabricated honeycomb structure with a prescribed upward angle of the channels that induce the desired component of velocity (see, e.g., channels within vanes 1028 of FIG. 17).

[0181] FIGS. 17 and 18 provide references and angles for input air flow, including VaMow for the vector of airflow at the inlet, Vo_Powder for the vector of power dispersion, and Vweb for the vector of web direction. The frame of reference encompassing the airflow direction relative to the web (angle a in FIG. 18), can be rotated 9 degrees with respect to a gravitational frame of reference (e.g., horizontal). In some embodiments, it may be advantageous based on best web handling practices, for the web to incline through the coating chamber of a horizontal system. Since the behavior of the powder particles as they collide with the web is affected by the direction of gravity and the particles’ initial velocity vector relative to the web (angle P in FIG. 18), the angle of these vectors is critical in optimizing final uniformity of the coating and also in encouraging attachment of the particles to the moving web.

[0182] In some embodiments, the angle a in FIG. 18 can be about, e.g., 15-40° inclusive, 15-35° inclusive, 15-30° inclusive, 15-25° inclusive, 15-20° inclusive, 20-40° inclusive, 25-40° inclusive, 30-40° inclusive, 35-40° inclusive, 20-35° inclusive, 25-30° inclusive, 15°, 20°, 25°, 30°, 35°, 40°, or the like. In some embodiments, the angle P in FIG. 18 can be about, e.g., 45-90° inclusive, 45-85° inclusive, 45-80° inclusive, 45-75° inclusive, 45-70° inclusive, 45-65° inclusive, 45-60° inclusive, 45-55° inclusive, 45-50° inclusive, 50-90° inclusive, 55-90° inclusive, 60-90° inclusive, 65-90° inclusive, 70-90° inclusive, 75-90° inclusive, 80-90° inclusive, 85-90° inclusive, 50-85° inclusive, 55-70° inclusive, 60-65° inclusive, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 90°, or the like. Inn53MEl\58073023.vlAttorney Docket No. 137174.00100 some embodiments, the angle 9 in FIG. 18 can be about, e.g., 0-10° inclusive, 0-9° inclusive, 0-8° inclusive, 0-7° inclusive, 0-6° inclusive, 0-5° inclusive, 0-4° inclusive, 0-3° inclusive, 0-2° inclusive, 0-1° inclusive, 1-9° inclusive, 2-8° inclusive, 3-7° inclusive, 4-6° inclusive, 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, or the like.

[0183] Coating Chamber Conditions: Cross-Section Dimensions (width / depth / side wall gap / feed hopper width}

[0184] Another important consideration in the design of the system is the relationship between the desired width of coated web, the width of the powder injection stream, and the width of the internal walls of the main deposition zone. In some embodiments, the width of the powder injection stream should be at least as wide as the width of the corresponding web, and in general it is necessary to inject powder with a powder injection device (e.g., a dispensing roller) over a wider span than the web to ensure a uniform distribution of powder entering the main deposition zone. A minimum distance is required between the edge of the coated web and the walls of the system to ensure that build-up of powder on the edges does not occur, and to ensure that the web is properly isolated both mechanically and electrically from the walls. This distance should be at least about, e.g., 0.1-6 inches inclusive, 0.5-6 inches inclusive, 1-6 inches inclusive, 1.5-6 inches inclusive, 2-6 inches inclusive, 2.5-6 inches inclusive, 3-6 inches inclusive, 3.5-6 inches inclusive, 4-6 inches inclusive, 4.5-6 inches inclusive, 5-6 inches inclusive, 5.5-6 inches inclusive, 0.1-5.5 inches inclusive, 0.1-5 inches inclusive, 0.1-4.5 inches inclusive, 0.1-4 inches inclusive, 0.1-3.5 inches inclusive, 0.1-3 inches inclusive, 0.1-2.5 inches inclusive, 0.1-2 inches inclusive, 0.1-1.5 inches inclusive, 0.1-1 inches inclusive, 0.1-0.5 inches inclusive, 0.5-5 inches inclusive, 1-4 inches inclusive, 1-3 inches inclusive, 0.5-2.5 inches inclusive, 0.5-2 inches inclusive, 0.5-1.5 inches inclusive, 0.5-1 inch inclusive, 1-2.5 inches inclusive, 1.5-2.5 inches inclusive, 2-2.5 inches inclusive, 0.1 inches, 0.5 inches, 1 inch, 1.5 inches, 2 inches, 2.5 inches, 3 inches, 3.5 inches, 4 inches, 4.5 inches, 5 inches, 5.5 inches, 6 inches, or the like, and can increase as needed based on the dimensional constraints of the system and its packaging.

[0185] Coating Chamber Conditions: Specific Attention to Start Point of Particulate Impact With Web

[0186] In some embodiments, the moving web can be positioned axially downstream of the powder injection inlet. For example, when the system uses a dispensing roller, the54MEl\58073023.vlAttorney Docket No. 137174.00100 web can enter the coating chamber and be positioned in the desired orientation downstream of the plane aligned with the dispensing roller. This ensures that only powder particles which have been aerodynamically carried by and dispersed into the air stream will deposit on the web, and any larger particles or agglomerated / undispersed portions of the injected powder particles will fall directly downward to be captured by one or more powder reclaim systems. In such embodiments, the powder reclaim system would be positioned upstream of the web within the coating chamber (e.g., directly below the dispensing roller).

[0187] In some embodiments, the system can include an upstream reclaim system, which can include, e.g., a collection hopper, a vacuum system, a belt conveyor, combinations thereof, or the like. In some embodiments, the upstream reclaim system can include a belt conveyor that moves across the width of the system underneath the powder feeder (e.g., under the dispensing roller). Such design of the conveyor can permit it to be nested against the inlet of the web as it enters the main deposition zone, providing a smooth transition between the powder particles that are reclaimed and the powder particles that deposit on the web. Adjacent positioning of the reclaim conveyor (or other system) and the web ensures that larger powder particles are captured on the conveyor and dispersed powder particles coat the web surface, while minimizing loss of powder particles inbetween the conveyor and the web. The speed of the conveyor can be variable such that depth of the reclaim pile is controllable. For example, FIG. 25 illustrates a powder reclaim system 1120 positioned adjacent to a proximal end of the web 1122 (e.g., immediately adjacent to the section of the web 1122 oriented horizontally and ready to receive powder particles for coating). The powder reclaim system 1120 can include multiple rollers 1124, 1126, 1128, 1130 that maintain movement and positioning of a conveyor 1132. As powder particles are dispersed over the web 1122 surface, any particles that miss the web 1122 can land on the conveyor 1132, which transports the particles around the rollers 1124-1130 and into a reclaim container 1134. The reclaimed powder particles can subsequently be reused for dry powder mixtures.

[0188] In some embodiments, the upstream reclaim system can include a collection hopper positioned underneath the particle injection location. In such embodiment, the web can be routed underneath the collection hopper and enters the system along a rotating roller bearing (e.g., a nose roller, or the like) which is mounted in close proximity to the collection hopper. In some embodiments, a baffle with an aerodynamic shape can be positioned on the upstream side of the nose roller to serve a dual purpose of guiding the airflow and55MEl\58073023.vlAttorney Docket No. 137174.00100 powder smoothly to the web and shielding the upstream portion of the web from collecting stray agglomerated powder particles.

[0189] Particulate Feeder: Angled Air, Sieve / Shaker Particulate Dispersion System

[0190] In some embodiments, the initial dispersion zone (i.e., the area directly below the powder particle injection site) can include one or more dispersion assemblies to achieve optimal uniform dispersion of the powder particles into the air stream. FIGS. 19-21 provide different views of such dispersion assemblies incorporated into the electrostatic coating system. The system generally includes a coating chamber 1030 with an inlet upstream of the outlet, and the web 1032 entering the coating chamber 1030 downstream of the inlet.

[0191] In some embodiments, as illustrated in FIG. 19, the powder dispensing apparatus 1034 (e.g., a hopper) can be recessed into an opening 1036 in the top surface of the coating chamber 1030, and dispenses powder particles 1038 into the coating chamber 1030. The dispersion zone is defined as directly below the dispensing apparatus 1034 and downstream of same. The dispensing apparatus 1034 discharges a controlled mass flow or volume flow of powder particles 1038 into the coating chamber 1030. A secondary mechanical device - a dispersion device 1040 - can be positioned upstream of the dispensing apparatus 1034 and within the coating chamber 1030. The dispersion device 1040 can include vanes or an array of honeycomb-shaped openings to induce angled air flow upward towards the immediate dispersion area from the dispensing apparatus 1034. Such upward air flow can break up clumps of powder particles to assist with optimized dispersion and uniform coating of the web.

[0192] In some embodiments, as illustrated in FIG. 20, the powder dispensing apparatus 1034 can be positioned above the coating chamber 1030 within a duct 1042 leading into the coating chamber 1030, such that powder particles 1038 first pass through the duct 1042 before dropping into the coating chamber 1030. The powder dispersion device 1044 can be positioned directly below the duct 1042 opening into the coating chamber 1030. The dispersion device 1044 can be in the form of one or more screens with an array of openings placed at the outlet of the duct 1042 and is actuated to move in a translational, rotational, and / or vibrational manner such that the powder stream is more finely dispersed into the air stream, and any agglomerates or non-uniformities in the powder discharge are minimized. In particular, as the powder particles 1038 drop onto the dispersion device 1044, the dispersion device 1044 acts as a sieve with shaking, oscillation56MEl\58073023.vlAttorney Docket No. 137174.00100 and / or vibration to break up agglomerates or non-uniformities in the powder particles 1038 before dispensing the powder particles 1038 into the air flow stream of the coating chamber 1030. Such operation also assists with optimized dispersion and uniform coating of the web.

[0193] In some embodiments, as illustrated in FIG. 21, the dispersion device 1044 can be replaced with a platform 1046 including multiple pins or rods 1048 formed therein. The array of rods 1048 defines a rough surface in a plinko-style arrangement through which the powder particles must navigate before being released into the coating chamber. The passage between the rods 1048 breaks up and spreads any non-uniformities in the powder particle mixture, smoothing the particulates falling across the web surface. The powder dispensing apparatus 1050 of FIG. 21 is illustrated as a dispensing roller.

[0194] Particulate Feeder: Air Injection / particulate Aeration System at FeederDischarge

[0195] In some embodiments, as illustrated in FIG. 22, another type of secondary mechanical device (i.e., a powder dispersion device 1060) can be included to disperse the powder stream. The dispersion device 1060 can be positioned directly below the duct 1042 serving as the outlet of the dispensing apparatus 1034. The device 1060 can include a separate volume of airflow, injected into the coating chamber at the outlet of the powder dispensing apparatus 1034 through one or more nozzles or continuous slots, or through a perforated plate with small holes, such that the turbulent energy of the introduced air acts on the powder stream to disperse agglomerates or non-uniformities. The arrangement of the nozzles, slots, and / or holes can be in various configurations, including but not limited to, e.g., one or more pipes, one or more flat plates or baffles, one or more airfoil shapes, an air knife, combinations thereof, or the like.

[0196] FIGS. 23A-C provide illustrations of different configurations of the dispersion device 1060. In FIG. 23 A, the dispersion device 1062 can be in the form of a single tube spanning the width and / or length of the duct 1042 with an airflow stream passing through the tube. Although illustrated in a horizontal orientation, in some embodiments, the tube could be vertically oriented (e.g., parallel to the gravitational pull on the particles). The tube includes multiple openings formed therein around the entire circumference which pushes the air stream through the openings and assists with dispersion of agglomerates or non-uniformities in the powder particles 1038 falling through or out of the duct 1042. In57MEl\58073023.vlAttorney Docket No. 137174.00100 some embodiments, the openings can direct air only in specific directions, e.g., upward towards the apparatus 1034, at an upward, non-perpendicular angle, in a sideways direction, or downward.

[0197] In FIG. 23B, the dispersion device 1064, 166 can be in the form of two or more tubes similar to the tube of FIG. 23A. Different orientations of the tubes can be used in parallel or in perpendicular positions relative to each other. The tubes include multiple openings that create airflow streams passing outward and into the powder particles 1038 falling from the dispensing apparatus 1034.

[0198] In FIG. 23C, the dispersion device 1068 can be in the form of an airfoil- shaped tube. In such embodiment, the trailing bottom edge of the tube can include openings that create airflow streams passing outward and into the powder particles 1038 falling from the dispensing apparatus 1034. The leading edge of the airfoil- shaped tube can act as one means to break up agglomerates or non-uniformities, and the airflow stream can assist with such breaking up of powder particles that remain grouped together after passing around the tube. In some embodiments, the sides and / or leading edge of the tube can also include openings for creation of airflow streams.

[0199] In some embodiments, one or more design features of the powder system can be varied to adjust the powder coating process of the substrate. For example, the geometry of the tunnel in the coating chamber can be modified or selected based upon, e.g., the path of the web traveling through the tunnel, the speed of the gas in the tunnel (characterized, for example, by the Reynolds number), aspects of powder management (e.g., drop out zones, maintaining regions beyond the tunnel free of powder), combinations thereof, or the like. In some embodiments, the uniformity of the air flow within the tunnel can be adjusted by, e.g., controlling the velocity profile and / or intermittency of the air flow. In some embodiments, the range of pressure and flow within, across and / or along the tunnel can be varies.

[0200] In some embodiments, aspects related to introduction of powder within the tunnel can be adjusted / controlled, e.g., the location of introduction, the rate of powder relative to rate of airflow, the method of powder introduction, or the like. For example, with respect to location, the system design can consider, e.g., location relative to tunnel walls, location relative to web (e.g., position of web, entrance of web, exist of web), or the like. In some embodiments, the method of powder introduction can include considerations58MEl\58073023.vlAttorney Docket No. 137174.00100 of, e.g., roll geometry, brush geometry, roll rotation rate, brush actuation and rates relative to roll, or the like.

[0201] In some embodiments, the system design can consider the electrostatic powder deposition approaches, e.g., DC field, AC field (pulsing, half-wave), positive corona, negative corona, corona generating electrodes (e.g., wires, pins / needles, knife edges / wavy), or the like. In some embodiments, the system design can consider the powder management, e.g., controlled points of effluence (inlets and / or outlets), pressure within the coating chamber held at particular pressures to reduce the amount of loose powder which may exit the coating chamber when the powder is not adhered to the moving web, maintaining the pressure below atmospheric (pressure surrounding the chamber), controlling the variation of the pressure within the coating chamber, limiting the variation below some threshold amount, reporting excursions in measured pressure from a range of acceptable pressures, taking a corrective action based upon the measured excursion (e.g., stopping the process), or the like. In some embodiments, the system design can consider other environmental factors, e.g., controlling the composition of gas species, air with controlled humidity, gas mixtures with and without water vapor, gas mixtures with and without water vapor, or the like.

[0202] In some embodiments, the dry powder mixture can include various components. Components can include, e.g., active materials, binder, and conductive additives, and the components can be provided in a powdered, or discrete, form. The components can be characterized by an average size, typically by volume, which can range from between about, e.g., 0.2 and 2 nm, inclusive, 1 and 10 nm, inclusive, 5 and 600 nm, inclusive, 0.5 and 5 um, inclusive, 2.5 and 10 um, inclusive, 5 and 50 um, inclusive, 25 to 200 um, inclusive, and in excess of 150 um, or the like, but most likely less than 2 mm. In some embodiments, the average particle size (on a volume basis) is between about, e.g., 5 and 15 um, inclusive.

[0203] In some embodiments, the coating system can include a coating chamber, a powder metering apparatus, a web handling system, an inlet gas control device, an outlet gas control device, and an electrostatic coating apparatus / assembly.

[0204] The coating system can, according to some embodiments, define an internal cavity (e.g., chamber 910) with a variety of openings and interfaces. The internal cavity may be in gaseous communication with an inlet gas control device via a gas inlet (e.g., air59MEl\58073023.vlAttorney Docket No. 137174.00100 inlet 904), and may be in gaseous communication with an outlet gas control device via a gas outlet (e.g., duct 912). The cavity may have further openings to permit the passage of the web through the coating chamber 910, such as a web inlet and a web exit. In some embodiments, the various entrances and exits of gas and web into and out of the coating system may be shared or dual purposed. For example, according to some embodiments, a gas inlet and web inlet may be the same or different; a gas inlet and web exit may be the same or different; a gas outlet and web inlet may be the same or different; a gas outlet and a web outlet may be the same or different. Further, the direction of a flow of gas and of the motion of a web may be the same or different; according to certain embodiments, the direction of gas flow and the direction of passage of the web may be in the same direction (e.g., both of the web and the gas move from left to right); according to certain embodiments, the flow of gas the motion of the web may be constructed and run in a counterflow configuration, where, for example, a motion of the web may be counter to the direction of motion of the gas (e.g., the web moves right to left and the flow of gas moves from left to right).

[0205] The coating chamber and cavity may be further configured to accept an amount, mass flow, or stream of dry battery electrode powder (e.g., particles 922). Various means of powder metering, dispensing, and conveying may be installed, arranged, or otherwise configured with the coating chamber to deposit desired amounts of battery electrode powder in the coating chamber. The configuration of the coating chamber may include a metering device connection that may comprise a flanged connection, joint, tube, pipe, or other orifice connecting a region outside of the coating chamber to the cavity formed by the coating chamber. Depending upon the type and manner of operation of the powder metering apparatus, the metering device connection may be located at various positions relative to the direction of motion of the web, gas inlet, gas outlet, web inlet, and web outlet. According to some embodiments, a means of powder metering may deliver both powder and gas to the coating chamber. According to some embodiments, a means of powder metering may deliver powder and remove some amount of gas from the coating chamber.

[0206] A powder metering apparatus may be configured in a variety of different ways. According to some embodiments, a powder metering apparatus may include a rotating roller (e.g., dispensing device 920) in communication with a reservoir (such as a storage hopper, bin, container, and the like) containing an amount of powdered battery electrode material to uptake an amount of battery electrode material onto a surface of the rotating60MEl\58073023.vlAttorney Docket No. 137174.00100 roller. According to some embodiments, the rotating roller may be embellished with a variety of surface textures, pockets, patterns, features, roughnesses, and the like, to capture defined amounts of battery electrode powder when in contact with a reservoir. The battery electrode powder deposited on such a roller may have excess material removed in a skimming operation, according to certain embodiments, with a skimming element (such as a doctor blade or similar precisely-positioned object) to admit and exclude amounts of dry battery electrode powder depending upon the position of the dry battery electrode powder relative to the roller and skimming element. In some embodiments, the skimming element may exhibit a cross section which is pointed, sharp, circular, a circular sector, wedge- shaped, or blunt.

[0207] In some embodiments, the system can include a hopper (e.g., hopper 916) positioned over the coating chamber. The hopper can be configured to receive the dry powder mixture and introduce the dry powder mixture into the coating chamber. In some embodiments, the system can include a dispensing roller (e.g., mechanical dispersion means) disposed below the hopper (e.g., dispensing device 920). The dispensing roller can rotate to initially disperse the dry powder mixture into the coating chamber.

[0208] The gas supply and gas exhaust devices configured in gaseous connection to the coating system contribute critically to the powder deposition process. According to some embodiments, the inlet gas control device may include a blower (e.g., blower 906) to impart momentum to an amount of gas and direct said gas into the coating chamber. According to some embodiments, the inlet gas control device may control a source of gas (such as a pressurized source of gas, a displacement pump, or other source) to direct an amount of gas into the coating chamber. In some embodiments, the inlet gas control device may include a sensor to sense a property of a gas or gas flow, including, for example, an amount of gas flow (on a mass or volume basis), a temperature of a gas flow, a humidity of a gas flow, a composition of species of a gas flow, a pressure of a gas flow (relative to another reference point of interest, and / or on an absolute basis), or any other relevant process measurement.

[0209] An outlet gas control device, located downstream of the coating chamber, may be configured in a variety of ways to improve and enable a successful deposition of dry battery electrode powder within a coating chamber. According to some embodiments, a gas outlet control device may include a dust collector, blower, fan, pump, or other device capable of accomplishing the motion of gas from the coating chamber through a gas outlet.61MEl\58073023.vlAttorney Docket No. 137174.00100According to some embodiments, the outlet control device may, while accomplishing the motion of gas from the coating chamber through a gas outlet, also apply a negative pressure, relative to the environment surrounding the coating chamber. According to some embodiments, the negative pressure applied may be between about 0 and 100 Torr, inclusive, lower than the pressure relative to the environment surrounding the coating chamber.

[0210] According to some embodiments, a pressure of a gas flow may be controlled about atmospheric pressure (e.g., 760 Torr) by 100 Torr. That is, the pressure may be controlled to any value between 660 Torr and 860 Torr. According to some embodiments, it may be desirable to control any value of atmospheric pressure with a high degree of fidelity, such that the pressure may be permitted to vary by less than 0.001 Torr, for example. In such embodiments, the inlet and / or outlet gas components can be regulated by, e.g., a central controller or processing device, to maintain the pressure within the coating chamber at the desired level or range.

[0211] According to some embodiments, it may be desirable to control the temperature of a gas within the coating chamber, e.g., with a controller and / or processing device associated with the system. For example, and according to some embodiments, depending upon the materials to be processed, a range of temperature may be required or preferred which is different than a standard value of room temperature commonly found in a manufacturing setting (e.g., any temperature above 10 °C and lower than 40 °C). Moreover, and according to some embodiments, it may be required or preferred to maintain a temperature at a specific value even if that value is within the range of room temperatures normally found within manufacturing environments, with an additional stipulation that the temperature not be permitted to vary beyond predefined temperature bounds. Such predefined temperature bounds may be within the range of + / - 1 °C, + / - 2 °C, + / - 5 °C or + / - 10 °C. Without being bound by theory, the set temperature and range of temperature bounds may be selected based upon temperatures at which properties of any components in the dry battery electrode powder material exhibit transitions in behavior. For example, and according to some embodiments, a set temperature and range of temperature bounds may be determined by at least one of (1) a softening point of a polymer binder (such as a Vicat softening point, for example), (2) a glass transition temperature of a polymer binder, (3) a melting point of a polymer binder, (4) a phase transition temperature of a component (such as a binder, for example), (5) a temperature at which the surface chemistry of a component62MEl\58073023.vlAttorney Docket No. 137174.00100 in the dry battery electrode powder material changes (such as an evolution of water, oxidation of a surface group, or reduction of a surface group, for example), or any other property which may feasibly vary in the range of temperatures in which a coating chamber may be controlled.

[0212] According to some embodiments, it may be desirable to control a humidity of the gas within the coating chamber. The powdered materials (such as dry battery electrode powdered materials) are, at least owing to their fine size and high surface area relative to their volume, sensitive to moisture in ways which may, according to certain embodiments, cause a change in the ability of an assemblage of dry battery electrode powdered materials to flow in response to stimuli (including gravity, gas flow, electric fields, and the like). According to some embodiments, it may be desirable to maintain a level of humidity to less than 40% relative humidity at 20 °C, less than 30% relative humidity at 20 °C, or less than 10% relative humidity at 20 °C. According to some embodiments, it may be desirable to specify a level of humidity of a gas within the coating chamber using a dewpoint, where the dewpoint may be between 10 and 0 °C, 0 and -10 °C, -10 and -20 °C, -20 and -40 °C, or less than -40 °C. In some embodiments, the humidity level within the coating chamber can be regulated to maintain within the desired range or at the desired value with a controller and / or processing device.

[0213] According to some embodiments, it may be advantageous to supply a specific type of gas, or mixture of types of gas, to the coating chamber. For example, and according to some embodiments, a type of gas may be air. According to some embodiments, a type of gas may be free of oxygen, such as nitrogen, argon, or mixtures thereof. According to some embodiments, a type of gas may be oxygen. According to some embodiments, a type of gas may be any mixture of hydrogen, helium, argon, oxygen, nitrogen, methane, carbon dioxide, carbon monoxide, or water.

[0214] In some embodiments, the inlet gas control device may report a sensor value to a separate system component. For example, and according to some embodiments, the inlet gas control device may sense a pressure at a location within the inlet gas control device and report a value corresponding to the pressure to a separate component of the overall coating system; the inlet gas control device may also, instead of or in addition to, accept the value of a sensor located in a separate component of the coating system and use at least the value of the sensor to configure a parameter of the inlet gas control device. According to some63MEl\58073023.vlAttorney Docket No. 137174.00100 embodiments, the parameter configured may include any parameters which control a source of gas supplied by the inlet gas control device to the coating chamber, such as a mass flow of gas, gas flow velocity, volumetric gas flow, and the like. In some embodiments, the sensors can be in communication with a central processing device and / or controller, which is configured to communicate with components of the system to regulate the chamber pressure, chamber and / or gas temperature, chamber and / or gas humidity, gas speed, gas volume, a gas type, combinations thereof, or the like.

[0215] For example, FIG. 27 is a block diagram of an exemplary powder system in accordance with embodiments of the present disclosure. The system can include an air supply device, a gas inlet, and an inlet gas control device, each of which can be in communication with or includes one or more pressure sensors, flow sensors, speed sensors, or the like. The system includes a coating chamber connected to a powder metering system, the coating chamber also including or in communication with a pressure sensor, a flow sensor, and / or a speed sensor. The system can include a gas outlet and an exhaust device, each of which can be in communication with or includes one or more pressure sensors, flow sensors, speed sensors, or the like.

[0216] The spatial and temporal of gas flow within the coating chamber can be important to assure repeatability and uniformity of deposited dry battery electrode powder. According to certain embodiments, turbulence control structures (e.g., screens 1003, or the like) may be included across a flow path of the gas through the inlet gas control device. The turbulence control structures may be configured to increase the uniformity (in space and time) of characteristics of the turbulent flow after the flow interacts with the turbulence control structures, where the measurement of the turbulence characteristics is compared to the same characteristics of the flow prior to interaction with the turbulence control structures. Further to this point and for the removal of doubt, uniformity characteristics of the flow incident to the turbulence control structures are desired to be enhanced, according to some embodiments. Characteristics of the flow may include fluctuations in speed, velocity in various directions (e.g., with respect to any orthogonal coordinate system), acceleration in various directions, askew of a flow velocity (or speed), a kurtosis of a flow velocity (or speed), or any other statistical measurement or moment of the flow. According to some embodiments, a characteristic of the flow may future include a standard deviation of a flow velocity (or speed).64MEl\58073023.vlAttorney Docket No. 137174.00100

[0217] In some embodiments, the turbulence control structure can include an array of openings through which the air flow passes. In some embodiments, the openings of the array can each define a honeycomb configuration. In some embodiments, the openings of the array may be circular, ellipsoidal, square, triangular, or other geometric form. Typically, the turbulence controlling structure is between about, e.g., 50-90% inclusive, 50-80% inclusive, 50-70% inclusive, 50-60% inclusive, 60-90% inclusive, 70-90% inclusive, 80- 90% inclusive, 60-80% inclusive, 50%, 60%, 70%, 80%, 90%, or the like, open from an area cross-section perspective.

[0218] Various sizes of a turbulence controlling structure may be utilized to achieve a desired amount of turbulence control and uniformity. According to some embodiments, the turbulence controlling structure may be characterized by a length and a wetted diameter. For example, and according to some embodiments, a length of the turbulence control structure (aligned with the direction of the gas flow) may be varied to impart more (longer) or less (shorter) regularization to the flow. In certain embodiments, the length may be between about, e.g., 2 and 50 mm, inclusive, 25 and 100 mm, inclusive, 50 and 200 mm, inclusive, 150 and 500 mm, inclusive, 250 mm and 1 m, inclusive, or the like. According to some embodiments, a wetted diameter (four times the cross-sectional area of the structure opening divided by the perimeter of the structure opening) may be configured to be smaller or larger depending upon the degree and type of turbulence control desired. For example, and according to some embodiments, the wetted diameter may be between about, e.g., 1 and 5 mm, inclusive, 2 and 50 mm, inclusive, 25 and 100 mm, inclusive, in excess of 50 mm, or the like.

[0219] The layout, configuration, and geometry of coating chamber may impact the performance of the coating quality. According to some embodiments, the extents of the coating chamber should be designed in recognition of the width of the web, the desired length of the web to residing at any point within the coating chamber, the speed at which the web transits the coating chamber, the mass flux of the metered dry battery electrode powder into the coating chamber, any loss of material metered into the coating chamber but not captured by the web (which, with the mass flux metered may be used to compute at transfer efficiency of coating), the desired rate and properties of the flowing gas within the coating chamber, and / or other properties and variables may affect the design of the chamber geometry.65MEl\58073023.vlAttorney Docket No. 137174.00100

[0220] According to some embodiments, it may be generally desired to maintain a uniform flow of gas in regions where a powdered battery electrode material is carried in a gas and may subsequently interact with a surface of the web desired to be coated. For example, powdered battery electrode material metered into a coating chamber and conveyed, at least, by a flow of gas moving relative to the web is generally desired to be uniformly distributed such that any amount of material depositing onto the moving web will deposit evenly (or substantially evenly) in the transverse direction at positions along the web (or, equivalently, at positions along the coating chamber aligned with the direction of motion of the web). According to some embodiments, a uniform concentration of dry battery electrode powder carried in a gas stream and maintained at positions beyond a free surface of the web may enable a uniform deposition of dry battery electrode powder as a uniform difference in particulate concentration (set in the gas phase by the amount of metered powder and the flow properties of the vs. zero gas phase) may then drive a uniform flux of powdered battery electrode material toward the surface of the web to be coated. According to some embodiments, the geometric configuration of the coating chamber may directly affect a primary flow of the gas carrying the powdered battery electrode material through the coating chamber.

[0221] Further to the geometric configuration of the coating chamber, it may be desirable, according to some embodiments, to size the coating chamber depending upon the web width and web position to account for flow effects imparted by the coating chamber walls. For example, the flow of a gas through a conduit, as the coating chamber may be reckoned, may exhibit a variety of different flow regions depending upon the balance of forces imposed upon the gas (e.g., inertial, viscous, electric, gravitational, and the like) and the distance of the web and / or a desired region of gas flow from a wall of the internal cavity defined by the coating chamber. A flow of gas will sense the presence of walls of the internal cavity differently depending upon the location of the wall, the inertial forces in the flow of the gas, and the viscous forces in the flow of the gas. Typically, the amount of communication may be estimated using scalings associated with boundary layer flow within ducts and over plates. Specifically, this requires computation or estimation of a Reynolds number (a ratio of inertial to viscous forces) along with an indication of a length scale along the flow. Using these two parameters, a thickness of a boundary layer (a layer in which viscous effects are present in the flow, as compared to a region beyond the boundary layer where inertial effects are dominant). Various estimates of a boundary layer66MEl\58073023.vlAttorney Docket No. 137174.00100 thickness may be concocted, which generally follow the form 8 «rr where 5 is the Re lx estimated boundary layer thickness, f is a length along the flow (distance along the coating chamber from the gas inlet), a and x are constants depending upon the form of the boundary layer thickness estimate, and Re is a Reynolds number of the flow providing an estimate ofthe ratio of inertial to viscous forces provided by Re = where p is the density of theflowing gas, u is an average velocity of the flowing gas (defined, for example, by the volumetric flow divided by the cross-sectional area of the coating chamber), L is a characteristic length scale of the flow (for example, the hydraulic diameter of the internal cavity), and q is a dynamic viscosity of the flowing gas. It should be pointed out that such estimates are generally regarded as minimum requirements, according to certain embodiments. Typical values of the constant a may be between 0.1 and 0.5, and typical values of the constant x may be between 5 and 7.

[0222] In certain embodiments, and in recognition of the above, it will be desired to set the distance between an edge of the web and a point of closest approach to the wall (e.g., the wall of the coating chamber positioned immediately adjacent to the edge of the web) to be large as compared to a boundary layer thickness at the wall. In setting such distances, factors of 10, 100, and 1000 may be desired; for example, if the boundary layer thickness is determined to be about 1 mm, a factor of 10 will require a distance of about 10 mm, a factor of 100 will require a distance of about 100 mm, and a factor of 1000 will require a distance of about 1 m. According to some embodiments, factors between 10 and 100, 50 and 200, 100 and 500, or greater than 500 may be employed.

[0223] Additional considerations may also be utilized to size the coating chamber. According to some embodiments, it may be desirable to provide a vertical spacing between the upper surface of the web (above which a gas and suspension of dry battery electrode powder is flowing) sufficient to maintain a characteristic of the gas flow (e.g., the vertical distance as measured between the top surface of the web and the inner surface of the coating chamber top wall, or any chamber wall positioned directly above the top surface of the web). For example, the characteristic may be an average velocity, a property of a turbulent flow (e.g., a standard deviation of a flow velocity, a skew of a flow velocity, a kurtosis of a flow velocity, for example), a stagnation pressure, a mass flux of gas, or any other characteristic that may be used to differentiate a first gas flow from a second gas flow. In67MEl\58073023.vlAttorney Docket No. 137174.00100 such embodiments, it may be desired to maintain, generally, a cross-sectional area of the coating chamber along the direction of the web motion.

[0224] Further, and according to some embodiments, the tunnel cross-section may be configured to provide an acceleration of the flow along the motion of the flow. For example, the coating chamber may be desired to converge toward the gas outlet via a taper. A taper may be configured in at least one or in several directions (e.g., on a cavity surface above a web, below a web, to a side of a web, or on all surfaces surrounding the web, for example). In the cases where the coating chamber cavity is cylindrical or substantially cylindrical, a taper may be present in a cone shape. In the cases where the coating chamber is square, rectangular, or otherwise rectilinear the chamber may taper as a pyramid or other acumination.

[0225] According to some embodiments, the coating chamber may be configured with a gas inlet and a gas outlet. The gas inlet may enable gaseous communication between the coating chamber and an inlet gas control device, and the gas outlet may enable gaseous communication between the coating chamber and an outlet gas control device. The gas inlet and gas outlet (collectively referred to as ’’outlets”) may take the form of ducts, pipes, and the like to convey gas or otherwise permit the transport of gas and / or dry battery electrode powder. The outlets may include a flange, mount, joint, thread, seal, or other interface to accommodate a connection between gas control devices and the coating chamber.

[0226] The web upon which the dry battery electrode powder is deposited travels through the coating chamber. The configuration of the path which the web follows is an important design consideration. According to some embodiments, the web path may be controlled, guided, or otherwise directed by rolling elements (e.g., rollers 926, 928, 930), such as idler rollers (rollers configured to exert no or minimal tangential force), driven rollers (rollers which rotate at a determined rate of rotation, which may be the same or different than the speed of the web, and which may also exert a tangential force on the web), exhibiting various amounts of web wrap around the rollers (i.e., the amount of contact, typically an angular measurement with units of radians, degrees, and the like) between the web and roller.

[0227] According to some embodiments, the coating chamber may be configured to house at least one roller within the cavity of the coating chamber. According to some embodiments, the at least one roller may be an idler roller or a driven roller. According to68MEl\58073023.vlAttorney Docket No. 137174.00100 some embodiments, the at least one roller may be coupled to a drive mechanism (such as a motor, driveshaft, chain, belt, gear, or the like) to impart a motion to the at least one roller which may be the same or different than the motion of the web at a point where the web and the at least one roller contact. According to some embodiments, at least a pair of rollers may be coupled with a chain, belt, gear, or other motion element to drive the at least one pair of rollers in a simultaneous, concerted, or deterministic motion.

[0228] The at least one roller may be configured in a variety of paths or geometric configurations with respect to other guiding elements (such as rollers, nips, the like) at regions outside of the coating chamber. According to some embodiments, at least one roller may guide the web in a meandering path where the web undulates, including alternating contact between the roller and surface of the web (such that for a first and second roller which a web traverses, the first roller contacts a first side of the web, and the second roller contacts a second side of the web, where the first and second sides of the web are different, for example). According to some embodiments, at least one roller may be configured to direct the web at a constant slope or angle within the coating chamber. According to some embodiments, the at least one roller may be configured to direct the web at a varying slope, such that the web is guided along a path at a first slope, and subsequently guided along a path at a second slope different than the first slope. According to some embodiments, the web path may be arched. According to some embodiments, the web path may be vertical (relative to horizontal) for at least some length between a pair of rollers. According to some embodiments, the web path may be of similar length to the length of the coating chamber. According to some embodiments, the web path within the coating chamber may be greater than the length of the coating chamber (for example, by an amount between and equivalent to 1 and 1.2 times the length of the coating chamber). According to some embodiments, the web path within the coating chamber may be substantially greater than the length of the coating chamber (for example, by an amount exceeding 1.2 times the length of the coating chamber).

[0229] The path of gas flow may be regulated for the overall performance of the coating chamber, and the deposition of the dry battery electrode powder on a web more generally. According to some embodiments, a gas path may be configured to follow the path of the web as the web travels through the coating chamber. According to some embodiments, the gas path may be configured to intersect, or attempt to intersect, the web as the web travels through the coating chamber. Intersection of gas forming a gas path and the web may imply69MEl\58073023.vlAttorney Docket No. 137174.00100 that streamlines of the gas flow would intersect with the geometric location of the web were the web absent from its location (as the web is generally impermeable to gas flow).

[0230] According to some embodiments, a specific gas flow, or rate of flow of gas, may be desired. A gas flow or rate of flow of gas may be a volumetric flow, described, for example, with units of volume per time (or standard volume per time, specified at a reference pressure and temperature) such as cubic meters per second, cubic feet per minute, or any other measure of volume per time. According to some embodiments, it may be desired to specify a mass flow or rate of mass flow. A mass flow or rate of mass flow may be specified in units of mass per time, such as kilograms per second, or pounds per minute, for example. The product of an average velocity and a cross-sectional area of a coating chamber (or cavity formed thereby), where the cross-section corresponds to any area crosssection normal to the direction of the flow, may be used to determine a rate of flow of gas, and further, multiplying a rate of flow of gas by a density of the flowing gas may be used to compute a rate of mass flow of the gas within the chamber. A controller can be used to regulate the gas inlet component and / or the gas outlet component to ensure the desired gas flow or rate of flow (or range of same) is achieved and maintained.

[0231] According to some embodiments, a flow of gas within a coating chamber may be determined using a desired Reynolds number, geometric parameters of the coating (such as a coating chamber cross-sectional area), physicochemical properties of the flowing gas (such as a density and kinematic viscosity), and a characteristic length of the flow (such as a hydraulic diameter of the coating chamber cross-sectional area). According to some embodiments, a flow of gas within a coating chamber may be in a range between about, e.g., 10 and 100 cubic feet per minute, inclusive, 50 to 200 cubic feet per minute, inclusive, 100 to 500 cubic feet per minute, inclusive, 250 to 1000 cubic feet per minute, inclusive, above 1000 cubic feet per minute, or the like.

[0232] There are a variety of electrostatic coating configurations which may be utilized to accomplish the electrostatic coating, or electrostatically augmented coating, of dry battery electrode powder onto a moving web. These configurations may include an electrode assembly arrayed around, above, near, or otherwise in the vicinity of a moving web, according to some embodiments. These configurations may further include specification of a voltage or current applied to an electrode assembly.70MEl\58073023.vlAttorney Docket No. 137174.00100

[0233] According to some embodiments, an electrostatic coating configuration may include at least one electrode. According to some embodiments, the at least one electrode may be a wire, pin, sheet, edge, or other structure which is of high curvature (or tapers to a region of high curvature), is pointed, or otherwise sharp edged. According to some embodiments, the electrode may include an object with regions of high and low curvature, the regions of high curvature appearing at least as prominent features.

[0234] Polarity: According to some embodiments, a positive polarity may be applied to an electrode with respect to a ground potential. According to some embodiments, a negative polarity may be applied to an electrode with respect to a ground potential. According to some embodiments, a moving web (or current collector, such as a foil) may be held at a ground (e.g., grounded).

[0235] Electric field control - DC: According to some embodiments, a potential applied to an electrode may be configured, maintained, or otherwise held at a constant voltage, sometimes known as a DC voltage. According to some embodiments, a potential applied to an electrode may be maintained at a voltage which exhibits variations small as compared to an average voltage over an averaging time period; an averaging time period may be in the range of between about, e.g., 1 and 10 seconds, inclusive, 10 and 100 seconds, inclusive, 100 and 300 seconds, inclusive, or any other time period sufficient to compute a stable average voltage. According to some embodiments, a polarity of an electrode may exhibit a magnitude of between about, e.g., 1 and 10 kilovolts, inclusive, 5 and 25 kilovolts, inclusive, 20 and 50 kilovolts, inclusive, 30 and 120 kilovolts, inclusive.

[0236] Electric field control - AC: According to some embodiments, a time-varying potential may be applied to at least create a time-varying field between the at least one electrode and the web (or current collector or foil). A time-varying potential may also include a waveform such as a sine, cosine, chirp, ramp, triangle, square, triangle, pulse, or other time-varying waveform. A time-varying potential may include a periodic waveform. A periodic waveform may include a sine or cosine wave at a single frequency or at a variety of frequencies, a triangle wave, a square wave, a sawtooth, or any other periodic wave. A periodic waveform may also be truncated, such as, for the purposes of providing a nonlimiting example, a half-wave sine or cosine wave. A time-varying potential may include a modulated waveform. A modulated waveform may include a frequency or amplitude modulated waveform.71MEl\58073023.vlAttorney Docket No. 137174.00100

[0237] According to some embodiments, a specific output of current or current density may be desired from at least one electrode.

[0238] Current control - DC: According to some embodiments, a desired current output may be maintained, controlled, or otherwise configured for supply for at least one electrode. A desired current output may be specified via a total amperage desired to the at least one electrode, and / or by a specification of a current density, on an area basis, to the at least one electrode. According to some embodiments, the current or current density may be configured, maintained, or otherwise held at a constant current, sometimes known as a DC current. According to some embodiments, a current or current density desired at an electrode may be maintained at a current or current density which exhibits variations small as compared to an average current or current density over an averaging time period; an averaging time period may be in the range of between about, e.g., 1 and 10 seconds, inclusive, 10 and 100 seconds, inclusive, 100 and 300 seconds, inclusive, or any other time period sufficient to compute a stable average current or current density. According to some embodiments, a current of an electrode may exhibit a magnitude of between about, e.g., 0.01 and 0.1 microamperes, inclusive, 0.1 and 10 microamperes, inclusive, 10 and 100 microamperes, inclusive, 0.1 and 1 milliamperes, inclusive, 1 and 10 milliamperes, inclusive, above 10 milliamperes, or the like.

[0239] Current control - AC: According to some embodiments, a time-varying current output from at least one electrode may be desired. A time-varying current output may include a waveform such as a sine, cosine, chirp, ramp, triangle, square, triangle, pulse, or other time-varying waveform. A time-varying current output may include a periodic waveform. A periodic waveform may include a sine or cosine wave at a single frequency or at a variety of frequencies, a triangle wave, a square wave, a sawtooth, or any other periodic wave. A periodic waveform may also be truncated, such as, for the purposes of providing a non-limiting example, a half-wave sine or cosine wave. A time-varying current output may include a modulated waveform. A modulated waveform may include a frequency or amplitude modulated waveform.

[0240] Reporting of controlled and uncontrolled variables: According to some embodiments, the realized current, current density, and / or potential from or at the at least one electrode may be measured and / or recorded. According to some embodiments, any of the measured and / or recorded values may reported to a control system, data acquisition72MEl\58073023.vlAttorney Docket No. 137174.00100 system, display, human-machine interface, or other apparatus configured to provide immediate or latent communication.

[0241] Details on electrodes - wires dimension: According to some embodiments, an electrode may include a wire determined at least by a length and a diameter. According to some embodiments, a length may exceed the diameter by a factor in a range of between about 10 to 100. According to some embodiments, a length may exceed the diameter by a factor in a range of between about 100 to 1000. According to some embodiments, a length may exceed the diameter by a factor of greater than about 1000. According to some embodiments, a diameter of a wire may be in a range between about, e.g., 10 and 30 micrometer, inclusive, 25 to 100 micrometers, inclusive, 50 to 250 micrometers, inclusive, or the like.

[0242] Details on electrodes - wire composition: According to some embodiments, a wire may include of a metal or metal alloy. According to some embodiments, the metal or metal alloy may include tungsten, molybdenum, niobium, tantalum, rhenium, platinum, palladium, gold, silver, nickel, chrome, iron, or aluminum. According to some embodiments, a wire may be coated with a coating. According to some embodiments, a coating may include a refractory metal (such as tungsten, tantalum, molybdenum, rhenium, niobium, and the like) . According to some embodiments, a coating may include a precious metal (such as gold, silver, platinum, and the like).

[0243] In accordance with embodiments of the present disclosure, an exemplary system for powder coating is provided that includes a tunnel, uniform air, and powder deposition. The system can be for manufacturing battery electrodes, and can include a web handling apparatus. The web handling apparatus can be configured to control the speed and tension of a web as the web is conveyed through the system / chamber. The system includes a dry battery electrode powder metering system. The system includes a coating chamber defining an internal cavity in gaseous communication with an upstream air supply device via a gas inlet and a downstream air exhaust device via a gas outlet. The coating chamber includes a web inlet and a web exit. The coating chamber is configured to accept dry battery electrode powder for deposition of the dry battery electrode powder onto the web. The system includes an inlet gas control device upstream of the coating chamber. The system includes an outlet gas control device downstream of the coating chamber.73MEl\58073023.vlAttorney Docket No. 137174.00100

[0244] The inlet gas control device can include a blower. The inlet gas control device can include a turbulence control device having an inlet section and an outlet section. The turbulence control device can include a series of parallel ducts. The turbulence control device can produce a flow of gas at the outlet section with greater spatial uniformity as compared to a flow of gas at the inlet section. The series of parallel ducts can be characterized by a length with characteristic size between about 2 and 50 mm, and a wetted diameter with a characteristic size between about 5 and 100 mm.

[0245] At least one of the coating chamber, inlet control device, and outlet gas control device can include a sensor to measure a mass flow of gas. At least one of the coating chamber, inlet gas control device, and outlet gas control device can include a sensor to measure a static pressure of gas. the outlet gas control device can include a dust collector configured to apply a negative pressure at the gas outlet. The inlet gas control device can include a blower to direct an amount of gas into the coating chamber via the gas inlet. The application of the negative pressure can be controlled by a sensor located within at least one of (a) the coating chamber, (b) inlet gas control device, or (c) outlet gas control device. The application of the negative pressure can be controlled by a sensor located within at least one of (a) the coating chamber, (b) inlet gas control device, or (c) outlet gas control device.

[0246] The coating chamber can include a series of rolling elements to handle the web, The coating chamber can include an electrode spaced a distance away from a free surface of the web to permit the conveyance of dry battery electrode powder between the web and the electrodes. The electrode can be biased at a first voltage relative to a second voltage on the web. The second voltage can be held at a ground voltage. The first voltage can be between about 5 and 100 kV relative to a ground voltage. The first voltage can be between about -5 and -100 kV relative to a ground voltage.

[0247] In some embodiments, a wire can include the electrodes. The wire can exhibit an average diameter of greater than about 10 um and less than about 200 um. The first voltage can be a constant voltage. The first voltage can be time-varying. The time-varying voltage can be at least one of a pulsed voltage, a cyclic full-wave voltage, or a cyclic halfwave voltage.74MEl\58073023.vlAttorney Docket No. 137174.00100

[0248] In some embodiments, the system can include a tunnel and means for controlling the pressure within the tunnel below atmospheric pressure. The system can include a web entry and exist with respect to the tunnel and a scattering system.

[0249] 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.75MEl\58073023.vl

Claims

Attorney Docket No. 137174.00100CLAIMS:

1. A coating system for formation of a dry powder electrode, the coating system comprising: a coating chamber configured to receive a dry powder mixture, and further configured to receive a web including a top surface and an opposing bottom surface that travels through the coating chamber; and an airflow system configured to control airflow passing through the coating chamber.

2. The coating system of claim 1, wherein the airflow system includes an air supply disposed at or near an inlet of the coating chamber to flow air through the coating chamber, the air supply creating a controlled pressure within the coating chamber.

3. The coating system of claim 2, wherein the airflow system includes an air exhaust disposed at or near an outlet of the coating chamber to pull air through the coating chamber, the air exhaust creating a negative pressure within the coating chamber.

4. The coating system of claim 1, wherein the airflow system includes both an air supply disposed at or near an inlet of the coating chamber to push air through the coating chamber, and an air exhaust disposed at or near an outlet of the coating chamber to pull air through the coating chamber, a combination of the air supply and the air exhaust creating a balanced draft system having a controlled pressure and velocity within the coating chamber.

5. The coating system of claim 1, wherein the air supply system maintains an air velocity of about 25-750 fpm, inclusive, through the coating chamber.

6. The coating system of claim 1, wherein the air supply system maintains a static pressure of about -0.0001 to about -0.020 inches of water, inclusive, within the coating chamber.

7. The coating system of claim 3, comprising one or more sensors disposed within the coating chamber to detect airflow and pressure measurements within the coating chamber, and comprising a controller configured to automatically adjust in real-time operation of the air supply and the air exhaust of the airflow system to76MEl\58073023.vlAttorney Docket No. 137174.00100 maintain airflow and pressure within the coating chamber at desired levels.

8. The coating system of claim 1, wherein an inlet of the coating chamber defines a bell-mouth configuration with a decreasing cross- section.

9. The coating system of claim 1, comprising a settling screen disposed at or near an inlet of the coating chamber to generate a controlled velocity profile through the coating chamber.

10. The coating system of claim 1, wherein the air supply system is connected to an inlet of the coating chamber by an expansion section, the expansion section defining a gradual cross-sectional increase at an angle of about 5-9°, inclusive.

11. The coating system of claim 1, comprising a dispensing mechanism disposed over the coating chamber and configured to dispense the dry powder mixture from an outlet of the dispensing mechanism into the coating chamber.

12. The coating system of claim 11, wherein the airflow system includes means for directing airflow towards the outlet of the dispensing mechanism to disperse the dry powder mixture.

13. The coating system of claim 12, wherein the means for directing airflow towards the outlet comprises vanes or baffles angled upward relative to horizontal by an angle of about 5-50°, inclusive.

14. The coating system of claim 11, comprising a dispersion mechanism disposed at or near the outlet of the dispensing mechanism, wherein the dispersion mechanism is configured to act on the dry powder mixture to disperse the dry powder mixture.

15. The coating system of claim 14, wherein the dispersion mechanism includes a tube with a hollow interior and holes formed therein, wherein the tube is configured to receive airflow through the hollow interior such that air is forced out of the holes to apply a force on the dry powder mixture.

16. The coating system of claim 14, wherein the dispersion mechanism includes a screen with openings, wherein the screen is moved, translated, rotated or vibrated to disperse the dry powder mixture on and through the screen.77MEl\58073023.vlAttorney Docket No. 137174.0010017. The coating system of claim 1, comprising a turbulence controlling structure disposed at or near an inlet of the coating chamber, the turbulence controlling structure including an array of honeycomb openings configured to control turbulence in the airflow introduced into the coating chamber by the airflow system.

18. The coating system of claim 1, comprising one or more turbulence controlling structures disposed at or near an inlet of the coating chamber, wherein the one or more turbulence controlling structures are configured to control turbulence in airflow introduced into the coating chamber by the airflow system such that lateral uniformity is less than about + / -5% root mean square (RMS) from a target.

19. The coating system of claim 1, wherein a distance between edges of the web and interior surfaces of the coating chamber is at least about 0.1-6 inches, inclusive.

20. The coating system of claim 1, comprising electrodes disposed within the coating chamber or within an electrode assembly with an interior in fluid communication with the coating chamber.

21. The coating system of claim 20, wherein at least some of the electrodes are configured to electrostatically charge the dry powder mixture introduced into the coating chamber.

22. The coating system of claim 21, wherein at least some of the electrodes are configured to guide the electrostatically charged dry powder mixture towards the web for coating.

23. The coating system of claim 1, comprising a powder reclaim system disposed adjacent to a proximal end of the web within the coating chamber, wherein the powder reclaim system is configured to capture the dry powder mixture that fails to coat the web.

24. The coating system of claim 1, wherein the dry powder mixture comprises at least one of an active material, a conductive additive, or a binder.

25. The coating system of claim 1, comprising a calendering assembly configured to compress the dry powder mixture on at least one of the top surface or the78MEl\58073023.vlAttorney Docket No. 137174.00100 opposing bottom surface of the web to form a dry powder coating on the web.

26. A method of coating for formation of a dry powder electrode, the method comprising: passing a web through a coating chamber of a coating system, the web including a top surface and an opposing bottom surface; introducing a dry powder mixture into the coating chamber; and operating an airflow system to control airflow passing through the coating chamber.

27. A coating system for formation of a dry powder electrode, the coating system comprising: a coating chamber configured to receive a dry powder mixture, and further configured to receive a web including a top surface and an opposing bottom surface that travels through the coating chamber; an airflow system configured to control airflow passing through the coating chamber, wherein (i) the airflow system includes an air supply disposed at or near an inlet of the coating chamber to flow air through the coating chamber, the air supply creating a controlled pressure within the coating chamber, and (ii) the airflow system includes an air exhaust disposed at or near an outlet of the coating chamber to pull air through the coating chamber, the air exhaust creating a negative pressure within the coating chamber; one or more sensors disposed within the coating chamber to detect airflow and pressure measurements within the coating chamber; and a controller configured to automatically adjust in real-time operation of the air supply and the air exhaust of the airflow system to maintain airflow and pressure within the coating chamber at desired levels.

28. A coating system for formation of a dry powder electrode, the coating system comprising: a coating chamber configured to receive a dry powder mixture, and further configured to receive a web including a top surface and an opposing bottom surface that travels through the coating chamber; and a charging assembly disposed within or adjacent to the coating chamber; wherein the charging assembly is configured to charge particles of the dry79MEl\58073023.vlAttorney Docket No. 137174.00100 powder mixture introduced into the coating chamber, and guide the charged particles towards the web.

29. The coating system of claim 28, wherein the charting assembly is configured to electrostatically charge the particles of the dry powder mixture, and guide the electrostatically charged particles towards the web.

30. The coating system of claim 28, comprising an airflow system configured to control airflow passing through the coating chamber.

31. The coating system of claim 30, wherein the airflow system controls the airflow to guide the dry powder mixture introduced into the chamber towards the charging assembly.

32. The coating system of claim 30, wherein the airflow system controls the airflow to guide the charged particles towards the web.

33. The coating system of claim 30, wherein the airflow system disperses the dry powder mixture within the coating chamber.

34. The coating system of claim 28, wherein the charging assembly is disposed over the coating chamber and includes an opening in a bottom side such that an interior of the charging assembly is fluidly and aerodynamic ally open to an interior of the coating chamber.

35. The coating system of claim 28, wherein the charging assembly includes a housing formed at least partially from a deflection shield to enclose an interior of the charging assembly, and prevent escape of the particles of the dry powder mixture and / or powder charging ions.

36. The coating system of claim 28, wherein the charging assembly includes a housing, a first set of electrodes disposed within an interior of the housing, and a second set of electrodes disposed within the interior of the housing.

37. The coating system of claim 36, wherein the second set of electrodes is positioned offset from the first set of electrodes and in electrical isolation from the first set of electrodes.80MEl\58073023.vlAttorney Docket No. 137174.0010038. The coating system of claim 36, wherein the first set of electrodes is configured to electrostatically charge the particles of the dry powder mixture introduced into the coating chamber.

39. The coating system of claim 38, wherein the first set of electrodes is biased to provide an electric field strength of about 0.1-25 kV / cm, inclusive.

40. The coating system of claim 36, wherein the second set of electrodes is configured to guide the charged particles towards the web.

41. The coating system of claim 36, wherein the first set of electrodes includes charged wires positioned in a spaced manner along the same plane and extending a width of the charging assembly.

42. The coating system of claim 36, wherein the second set of electrodes includes linear rod electrodes extending a width of the charging assembly.

43. The coating system of claim 36, wherein the second set of electrodes produces an electric field of varying strength and geometry to create a directed potential gradient for guiding the charged particles towards the web.

44. The coating system of claim 35, wherein the second set of electrodes is in a form of a grid, a mesh, or plates.

45. The coating system of claim 36, wherein a distance between the second set of electrodes of the charging assembly relative to each other is selected to increase an electric field uniformity generated by the electrodes.

46. The coating system of claim 45, wherein the distance between electrodes relative to each other is between about 1-20 cm, inclusive.

47. The coating system of claim 28, wherein the dry powder mixture includes active materials, binder, and conductive additives.

48. The coating system of claim 28, wherein an average powder velocity immediately downstream of the charging assembly is between 25-750 feet per minute, inclusive.81MEl\58073023.vlAttorney Docket No. 137174.0010049. The coating system of claim 28, comprising a dispensing mechanism disposed over the coating chamber and configured to dispense the dry powder mixture from an outlet of the dispensing mechanism into the coating chamber.

50. The coating system of claim 28, comprising a dispersion mechanism disposed at or near the outlet of the dispensing mechanism, wherein the dispersion mechanism is configured to act on the dry powder mixture to disperse the dry powder mixture.

51. The coating system of claim 50, wherein the dispersion mechanism includes a tube with a hollow interior and holes formed therein, wherein the tube is configured to receive airflow through the hollow interior such that air is forced out of the holes to apply a force on the dry powder mixture.

52. The coating system of claim 50, wherein the dispersion mechanism includes a screen with openings, wherein the screen is moved, translated, rotated or vibrated to disperse the dry powder mixture on and through the screen.

53. The coating system of claim 28, wherein electrodes of the charging assembly create a varying electric field strength between the electrodes and the web in a downstream direction of the coating chamber to charge and guide the charged particles towards the web.

54. The coating system of claim 28, wherein electrodes of the charging assembly create a varying electric field strength between the electrodes and the web which increase in strength in a downstream direction of the coating chamber.

55. The coating system of claim 28, wherein electrodes of the charging assembly create a varying electric field strength between the electrodes and the web which decreases in strength in a downstream direction of the coating chamber.

56. The coating system of claim 28, wherein electrodes of the charging assembly produce a varying electric field strength relative to the web at equal vertical positions to the web and with varying potentials at individual electrode surfaces.

57. The coating system of claim 28, wherein electrodes of the charging assembly produce a varying electric field strength relative to the web at equal potentials at individual electrode surfaces and varying vertical and horizontal positions relative82MEl\58073023.vlAttorney Docket No. 137174.00100 to the web.

58. The coating system of claim 28, wherein electrodes of the charging assembly are in a narrowing configuration which is an arc configuration or a linear configuration shifting downwardly towards the web in a downstream direction of the coating chamber to guide the electrostatically charged particles towards the web.

59. The coating system of claim 28, wherein the charging assembly includes a corona charging mechanism.

60. The coating system of claim 28, wherein the charging assembly includes a tribocharging assembly.

61. A method of coating for formation of a dry powder electrode, the method comprising: passing a web through a coating chamber of a coating system, the web including a top surface and an opposing bottom surface; introducing a dry powder mixture into the coating chamber; charging particles of the dry powder mixture with a charging assembly disposed within or adjacent to the coating chamber; and guiding the charged particles towards the web with the charging assembly.

62. A system for manufacturing battery electrodes from a dry powder, the system comprising: a web handling apparatus, the web handling apparatus is configured to control a speed and tension of a web as the web is conveyed through a coating chamber; a dry battery electrode powder metering system; the coating chamber, wherein the coating chamber: defines an internal cavity, the internal cavity is in gaseous communication with an upstream air supply device via a gas inlet and a downstream air exhaust device via a gas outlet; includes a web inlet and a web exit; and is configured to accept the metered dry battery electrode powder for deposition of the dry battery electrode powder onto the web;83MEl\58073023.vlAttorney Docket No. 137174.00100 an inlet gas control device disposed upstream of the coating chamber; and an outlet gas control device disposed downstream of the coating chamber.

63. The system of claim 62, wherein the inlet gas control device includes a blower.

64. The system of claim 62, wherein the inlet gas control device includes a turbulence control device including an inlet section and an outlet section.

65. The system of claim 64, wherein the turbulence control device includes a series of parallel ducts.

66. The system of claim 65, wherein the turbulence control device produces a flow of gas at the outlet section with greater spatial uniformity as compared to a flow of gas at the inlet section.

67. The system of claim 65, wherein the series of parallel ducts are characterized by a length with characteristic size between about 2 and 50 mm, inclusive, and a wetted diameter with a characteristic size between about 5 and 100 mm, inclusive.

68. The system of claim 62, wherein at least one of the coating chamber, the inlet gas control device, or the outlet gas control device include a sensor configured to measure a mass flow of gas.

69. The system of claim 62, wherein at least one of the coating chamber, the inlet gas control device, or the outlet gas control device include a sensor configured to measure a static pressure of gas.

70. The system of claim 62, wherein the outlet gas control device includes a dust collector configured to apply a negative pressure at the gas outlet.

71. The system of claim 62, wherein the inlet gas control device includes a blower configured to direct an amount of gas into the coating chamber via the gas inlet.

72. The system of claim 70, wherein the application of the negative pressure is controlled by a sensor located within at least one of (a) the coating chamber, (b) the inlet gas control device, or (c) the outlet gas control device.

73. The system of claim 62, wherein the coating chamber further includes a series of84MEl\58073023.vlAttorney Docket No. 137174.00100 rolling elements configured to handle or support the web.

74. The system of claim 62, wherein the coating chamber further includes one or more electrodes spaced a distance away from a free surface of the web to permit conveyance of the dry battery electrode powder between the web and the electrodes.

75. The system of claim 74, wherein the electrodes are biased at a first voltage relative to a second voltage on the web.

76. The system of claim 74, wherein the second voltage is held at a ground voltage.

77. The system of claim 74, wherein the first voltage is between about 5 and 100 kV, inclusive, relative to a ground voltage.

78. The system of claim 75, wherein the first voltage is between about -5 and -100 kV, inclusive, relative to a ground voltage.

79. The system of claim 74, wherein a wire comprises the electrodes.

80. The system of claim 79, wherein the wire exhibits an average diameter of greater than about 10 um and less than about 200 um.

81. The system of claim 75, wherein the first voltage is a constant voltage.

82. The system of claim 75, wherein the first voltage is time-varying.

83. The system of claim 82, wherein the time-varying voltage is at least one of a pulsed voltage, a cyclic full-wave voltage, or a cyclic half-wave voltage.85MEl\58073023.vl

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