Sensor system for forming dry powder electrodes and method of use thereof

Abstract

A system and method for feeding powder is disclosed. The system includes a powder hopper, one or more sensors, a feeder hopper, and a processor in operative communication with the one or more sensors and the feeder hopper. The powder hopper is configured to feed powder to the roller pair. Each of the one or more sensors is configured to determine a characteristic of powder in the powder hopper. The feeder hopper is configured to feed powder to the powder hopper. The processor is configured to cause the feeder hopper to feed powder to the powder hopper in response to the characteristic of powder in the powder hopper being less than a threshold value.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 275,863, filed November 4, 2021, the entire contents of which are incorporated herein by reference.

[0002] SYSTEMS AND METHODS FOR MANUFACTURING ELECTRODES FROM DRY POWDER FIELD OF THE DISCLOSURE The present disclosure relates to systems and methods for manufacturing electrodes from dry powder, and more particularly, to systems and methods for controlling the supply of dry powder to a calendering system used in the manufacture of electrodes. [Background technology]

[0003] An electrode is a conductor through which charge passes to and from an object. An electrode can be implemented as part of an electrical energy storage cell, which is widely used to power electronic, electromechanical, electrochemical, and other useful devices. Energy storage cells include batteries, such as primary chemical cells and secondary (rechargeable) cells, fuel cells, and various types of capacitors, including ultracapacitors.

[0004] Electrodes have traditionally been manufactured using a wet process in which the active material, binder, and conductive agent are mixed together in a slurry. The slurry is then applied to a current collector substrate and allowed to dry. The solvent is recovered after the initial drying process. The substrate is passed through a calendering system to compress it and is dried again. The substrate is cut to form the electrodes.

[0005] One problem with traditional "wet" electrode production is that solvent recovery is an expensive, environmentally-sensitive, and potentially hazardous process. The solvents used are toxic chemicals and can be harmful to workers. Additionally, the drying operation that results in the evaporation of the solvent also requires the consumption of significant amounts of energy. To prevent harm to the environment or operational personnel, the solvent must be recovered and properly disposed of.

[0006] More recently, "dry" (i.e., solvent-free) electrode manufacturing processes have been explored. Dry electrode manufacturing processes eliminate the need for solvents. Instead, such processes place dry powder material on a substrate and use a calendaring process to press the powder into an electrode. Because dry electrode manufacturing processes do not use solvents, the cost of solvents and their associated toxicity are eliminated. Additionally, the drying processes used to recover the solvent from the substrate are no longer needed.

[0007] However, the tight tolerances of the electrodes necessitate a consistent manufacturing process. To achieve this goal, the powders used to form the electrodes must be applied uniformly. Summary of the Invention

[0008] In some embodiments, the system includes a first powder hopper, one or more first sensors, a first feeder hopper, and a processor in operative communication with the one or more first sensors and the first feeder hopper. The first powder hopper is configured to feed a first powder to the first roller pair. Each of the one or more first sensors is configured to determine a characteristic of the first powder of the first powder hopper. The first feeder hopper is configured to feed the first powder to the first powder hopper. The processor is configured to cause the first feeder hopper to feed the first powder to the first powder hopper in response to the characteristic of the first powder of the first powder hopper being less than a first threshold.

[0009] In some embodiments, the first powder hopper is disposed adjacent to the first pair of rollers.

[0010] In some embodiments, the one or more first sensors include a level sensor and the characteristic of the first powder includes a height of the first powder within the first powder hopper.

[0011] In some embodiments, the one or more first sensors include a weight sensor, and the property of the first powder includes a weight of the first powder within the first powder hopper.

[0012] In some embodiments, the system further includes a second powder hopper, one or more second sensors, and a second feeder hopper. The second powder hopper is configured to feed the second powder to the second pair of rollers. Each of the one or more second sensors is configured to determine a characteristic of the second powder in the second powder hopper. The second feeder hopper is configured to feed the second powder to the second powder hopper. The processor is also in operative communication with the one or more second sensors and the second feeder hopper, and is further configured for the second feeder hopper to feed the second powder to the second powder hopper in response to the characteristic of the second powder in the second powder hopper being less than a second threshold.

[0013] In some embodiments, a second powder hopper is disposed adjacent to the second pair of rollers.

[0014] In some embodiments, the one or more second sensors include a level sensor and the characteristic of the second powder includes a height of the second powder within the second powder hopper.

[0015] In some embodiments, the one or more second sensors include a weight sensor and the property of the second powder includes a weight of the second powder within the second powder hopper.

[0016] In some embodiments, the first powder is the same as the second powder. In alternative embodiments, the first powder is different from the second powder.

[0017] In some embodiments, the first feeder hopper is connected to a second feeder hopper.

[0018] In some embodiments, the method includes feeding a first powder from a first powder hopper to a first roller pair, determining, by at least one first sensor, a characteristic of the first powder within the first powder hopper, and in response to the characteristic of the first powder being less than a first threshold, delivering the first powder from the first feeder hopper to the first powder hopper.

[0019] In some embodiments, the first powder hopper is disposed adjacent to the first pair of rollers.

[0020] In some embodiments, the at least one first sensor includes a level sensor and the characteristic of the first powder includes a height of the first powder within the first powder hopper.

[0021] In some embodiments, the at least one first sensor includes a weight sensor, and the property of the first powder includes a weight of the first powder within the first powder hopper.

[0022] In some embodiments, the method further includes feeding a second powder from a second powder hopper to a second pair of rollers, determining, by at least one second sensor, a characteristic of the second powder within the second powder hopper, and in response to the characteristic of the second powder being less than a second threshold, delivering the second powder from the second feeder hopper to the second powder hopper.

[0023] In some embodiments, a second powder hopper is disposed adjacent to the second pair of rollers.

[0024] In some embodiments, the at least one second sensor includes a level sensor and the characteristic of the second powder includes a height of the second powder within the second powder hopper.

[0025] In some embodiments, the at least one second sensor includes a weight sensor and the property of the second powder includes a weight of the second powder within the second powder hopper. [Brief description of the drawings]

[0026] Aspects, features, benefits, and advantages of the embodiments described herein will become apparent with reference to the following description, the appended claims, and the accompanying drawings.

[0027] [Figure 1] FIG. 1 shows a schematic diagram of an exemplary multi-roll calendering system according to an embodiment.

[0028] [Diagram 2] According to an embodiment, a combined calendar / laminator system is shown configured to fabricate two dry electrode films and laminate each dry electrode film to a current collector to form a double-sided electrode.

[0029] [Diagram 3] 1 illustrates a calendering system having a hopper according to an embodiment.

[0030] [Figure 4] 1 illustrates an exemplary feeder hopper configured to feed powder to a powder hopper according to an embodiment.

[0031] [Diagram 5] 1 illustrates a block diagram of an exemplary computing device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The disclosure is not limited to the particular systems, devices, and methods described, which may vary, and the terminology used herein is for the purpose of describing particular variations or embodiments only, and is not intended to limit the scope.

[0033] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Nothing in this disclosure should be construed as an admission that the embodiments described in this disclosure are not entitled to antedate such disclosure by virtue of prior invention. As used in this document, the term "including" means "including, but not limited to."

[0034] Energy storage cells or devices, such as lithium-ion batteries, have been relied upon as power sources in many commercial and industrial applications, including, but not limited to, consumer devices, productivity devices, and battery-powered vehicles. The demand for energy storage devices continues to grow. For example, the automotive industry is developing vehicles that rely on compact and efficient energy storage, such as plug-in hybrid vehicles and pure electric vehicles. Lithium-ion batteries are well-suited to meet future demands.

[0035] Electrodes are important components in determining and / or improving the storage potential of an energy storage device. The electromechanical capabilities of an electrode, such as the capacity and efficiency of a battery electrode, depend on a variety of factors. These factors include, but are not limited to, the distribution of the active material, binder, and one or more additives, the physical properties of the active material, binder, and additives, such as the particle size and surface area of ​​the active material, the surface properties of the active material, and the physical properties of the electrode film, such as the density, porosity, and cohesiveness of the film, and the adhesion of the film to the conductive element.

[0036] Dry electrode manufacturing systems and methods traditionally use high shear and / or high pressure processing steps to break down and mix electrode film materials. Such systems and methods may offer structural advantages over electrode films manufactured using wet processes. However, the high processing pressures and large amounts of equipment (and therefore large footprints) used to form dry free-standing electrode films and dry electrodes leave room for improvement.

[0037] The systems and methods provided herein can be implemented to manufacture dry electrode films and electrodes for various energy storage devices. As defined herein, the energy storage device can be a capacitor, a lithium ion capacitor (LIC), an ultracapacitor, a battery such as a lithium ion battery, or a hybrid energy storage device that combines two or more of the foregoing aspects.

[0038] Various embodiments described herein provide improved methods of manufacturing dry electrode films and dry electrodes for use in energy storage devices. The disclosed embodiments can provide a simplified, cost-effective procedure for manufacturing energy storage devices.

[0039] Embodiments of the systems and methods for forming dry electrode films disclosed herein may provide one or more advantages over conventional systems and methods. Some embodiments allow for the production of electrodes with uniform thickness in wide-format, high-precision, low-tolerance films. In some embodiments, multi-layer functional webs can be enabled by using one or more dry electrode material delivery systems, such as powder delivery hoppers. In some embodiments, a consistent amount of dry powder can be fed into the production of films to produce a consistent end product. Additional features or advantages provided by embodiments herein will be apparent to those skilled in the relevant art.

[0040] In some embodiments, the calendering system includes a hopper configured to receive the powder, the hopper configured to deliver the powder to rollers of the calendering system to ensure that a film of uniform thickness is formed, in some embodiments, the film may be used to form a dry electrode.

[0041] FIG. 1 shows a schematic diagram of an exemplary multi-roll calendering system according to an embodiment. The calendering system shown in FIG. 1 includes six rollers, although more or fewer rollers may be used. The calendering system may include one or more dry electrode material delivery systems, such as powder delivery hoppers. For illustrative purposes, the system in FIG. 1 includes two powder hoppers 101 and 102, although more or fewer powder hoppers may be used within the scope of the present disclosure. In some embodiments, the particle size, density, porosity and / or material type and / or other material properties of the powder in powder hopper 101 and the powder in powder hopper 102 may differ from each other. In alternative embodiments, the material properties of the powder in powder hopper 101 and 102 may be the same.

[0042] FIG. 2 illustrates a combined calendar / laminator system 200 configured to fabricate two dry electrode films and laminate each dry electrode film to a current collector to form a double-sided electrode. As shown in FIG. 2, a first powder hopper 202 can be configured to supply powder to a first set of rollers 204 and 205, and a second powder hopper 203 can be configured to supply powder to a second set of rollers 206 and 207. A current collector 210 can be provided from a current collector source 208. A first dry electrode film 220 can be formed by calendaring particles from the first powder hopper 202 through a first nip formed from the first set of rollers 204 and 205. A second dry electrode film 221 can be formed by calendaring particles from the second powder hopper 203 through a second nip formed between the second set of rollers 206 and 207. The first and second dry electrode films 220 and 221 may be laminated to opposing first and second sides, respectively, of the current collector 210. In some embodiments, the lamination may be provided by compressing (e.g., calendering) the first and second dry electrode films 220 and 221 and the current collector 210 between a third nip formed, for example, between rolls 205 and 206. In some embodiments, the third nip may also provide additional calendering and film thickness adjustment of the first and second dry electrode films 220 and 221. After laminating the electrode films 220 and 221 and the current collector 210, the double-sided electrode may be collected for further processing, for example, via an unwinding station 209.

[0043] By placing the roll nips consecutively and closely together as shown in FIG. 2, continuous calendering and reduction of the thickness of the film can be achieved. This can reduce or completely eliminate the need for idler or dancer rollers in the calendering system. Each of the rollers 204-207 may be speed and / or acceleration controlled. For example, subsequent rollers such as 205 and 206 may rotate slightly faster than previous rollers such as 204 and 207, respectively, to move the film along the rollers to the last section, where the film is unwound from the last roll and wound into the unwind station 209.

[0044] In alternative embodiments, the system shown in FIG. 2 may be implemented to produce a single-sided electrode, for example, but not limited to, by eliminating roll 207 and second powder hopper 203. Such a system does not produce electrode film 221. In some embodiments, rollers 204 and 207 may be part of a belt calendering system, where the belt provides additional support and surface area for applying the dry electrode material thereon. One or more belt systems, such as rollers 204 and 207, or one or more non-belt systems, such as 205 and 206, or combinations thereof, may be implemented according to the knowledge of one of ordinary skill in the relevant art.

[0045] Figure 3 illustrates a calendering system having a hopper according to an embodiment. As shown in Figure 3, powder hopper 301 may contain a quantity of powder 302 during operation. Powder hopper 301 may include one or more sensors, such as 303 and 304, configured to sense properties of powder 302 and / or the powder hopper.

[0046] In some embodiments, the first sensor 303 may be configured to determine a weight of the powder 302 inside the powder hopper 301. In some embodiments, the first sensor 303 may be configured to determine a weight of the powder hopper 301. In such embodiments, the first sensor 303 may be used to initially determine a first weight of the powder hopper 301 when there is no powder 302 and a second weight of the hopper when there is powder in the powder hopper. In such embodiments, multiple second weights of the powder hopper 301 may be determined by the first sensor 303 at periodic or aperiodic intervals. In some embodiments, the processor may use the second weight to determine the weight of the powder 302 in the powder hopper 301 at the time the second weight is sensed by subtracting the first weight from the second weight.

[0047] In some embodiments, the second sensor 304 may be configured to determine the level of powder 302 within the powder hopper 301. For example, the second sensor 304 may determine if the powder 302 within the powder hopper 301 exceeds a height threshold, such as the distance from a location 310 where the powder is configured to be released from the powder hopper to a peak 311 of the powder within the powder hopper. In some embodiments, if the peak 311 of the powder 302 is below the threshold, a light beam may be emitted from a light source (not shown) and received by the second sensor 304. If the peak 311 of the powder 302 exceeds the threshold, the light beam may be blocked and not received by the second sensor 304. The location of the light source and / or second sensor 304 may be determined based on an expected amount of powder 302 present in the powder hopper 301 during normal operation.

[0048] Alternative and / or additional embodiments of the system used to sense the amount of powder in the powder hopper will be apparent to those of ordinary skill in the relevant art based on the teachings of the present disclosure.

[0049] In some embodiments, one or more sensors may be spaced along the width of the hopper to determine the peak, height, density, weight, or other property(ies) of the powder at various points throughout the hopper. The locations of such peak, height, density, and weight sensors are not limited to the location of the first sensor 303 to the second sensor 304 of FIG. 3. For example, weight sensors or pressure (load) sensors may be placed along the sides of the powder hopper 301, either alone or in combination with sensors 304 configured to detect peaks or heights.

[0050] Figure 4 illustrates an exemplary feeder hopper configured to feed powder to a powder hopper according to an embodiment. As shown in Figure 4, the feeder hopper 401 is configured to feed a predetermined amount of powder 402 to the powder hopper 403 or at a predetermined rate over time. The feeder hopper 401 may include a variable feed rate to control the amount or rate at which the powder 402 is fed to the powder hopper 403.

[0051] In some embodiments, multiple feeder hoppers may be used to feed multiple powder hoppers. In some embodiments, the multiple feeder hoppers may be interconnected. In other words, the multiple feeder hoppers may house a common reservoir containing powder. In such embodiments, each feeder hopper may have a different discharge point from which the powder is discharged into the corresponding powder hopper.

[0052] Loading the powder hopper with a precise amount of powder allows the calendering system to achieve precise deposition and formation of the electrode. In particular, loading the powder hopper with a precise amount of powder can provide a uniform supply of powder to the calendering system. By keeping the amount of powder in the powder hopper constant, the density of the powder entering the nip can be uniform throughout the formation of a film, such as a dry electrode film. Thus, the amount of film variation can be significantly reduced.

[0053] FIG. 5 illustrates a block diagram of exemplary internal hardware that may be used to store or implement program instructions, such as process steps described herein, according to various embodiments. Bus 500 may serve as the primary information highway interconnecting the other illustrated components of the hardware. CPU 505 is the central processing unit of the system, performing the calculations and logical operations necessary to execute the programs. CPU 505, alone or in combination with one or more of the other elements disclosed in FIG. 5, is an exemplary processing device, computing device, or processor, as such terms are used in this disclosure. Read-only memory (ROM) 510 and random access memory (RAM) 515 constitute exemplary memory devices (i.e., processor-readable non-transitory storage media).

[0054] The controller 520 interfaces to the system bus 500 one or more optional memory devices 525. These memory devices 525 may include, for example, external or internal DVD drives, CD-ROM drives, hard drives, flash memory, USB drives, etc. As previously mentioned, these various drives and controllers are optional devices.

[0055] Program instructions, software, or interactive modules for providing an interface and performing any queries or analyses related to one or more data sets may be stored in ROM 510 and / or RAM 515. Optionally, the program instructions may be stored on a tangible computer readable medium, such as a compact disc, a digital disc, a flash memory, a memory card, a USB drive, an optical disc storage medium such as a Blu-ray™ disc, and / or other non-transitory storage medium.

[0056] An optional display interface 530 may allow information from the bus 500 to be displayed on a display 535 in audio, visual, graphic, or alphanumeric form, such as interfaces previously described herein. Communication with external devices, such as a printing device, may occur using various communication ports 540. An exemplary communication port 540 may be connected to a communication network, such as the Internet, an intranet, or the like.

[0057] The hardware may also include an interface 545 that enables receiving data from input devices such as a keyboard 550 or other input devices 555 such as a mouse, joystick, touch screen, remote control, pointing device, video input device, and / or audio input device.

[0058] The hardware may also include storage devices 560, such as, for example, connected storage devices, servers, and off-site remote storage devices. Exemplary off-site remote storage devices may include hard disk drives, optical drives, tape drives, cloud storage drives, and the like. Storage devices 560 are configured to store data as described herein, which may optionally be stored in database 565. Database 565 may be configured to store information in a manner that allows for indexing and searching, as described herein.

[0059] The computing device of FIG. 5 and / or its components may be used to perform various processes described herein.

[0060] In the above detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, like symbols typically identify like components unless otherwise indicated by context. The illustrative embodiments described in the detailed description, drawings, and claims are not intended to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings, can be arranged, substituted, combined, separated, and designed in a wide variety of configurations, as expressly contemplated herein.

[0061] The present disclosure is not limited to the specific embodiments described in this application, but is intended as an illustration of various aspects. As will be apparent to those skilled in the art, many modifications and variations can be made without departing from the spirit and scope thereof. Functionally equivalent methods and apparatuses that are within the scope of the present disclosure, as well as those recited herein, will be apparent to those skilled in the art from the above description. Such modifications and alterations are intended to be included within the scope of the appended claims. The present disclosure is limited only by the terms of the appended claims, and the full scope of equivalents to which such claims are entitled. It is to be understood that the present disclosure is not limited to specific methods, reagents, compounds, compositions, or biological systems, which can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of merely describing specific embodiments, and is not intended to be limiting.

[0062] With respect to the use of substantially any plural and / or singular term herein, those skilled in the art can convert from plural to singular and / or from singular to plural as appropriate to the context and / or application. For clarity, various singular / plural permutations may be explicitly set forth herein.

[0063] Those skilled in the art will understand that the terms used in the specification, in general, and in the claims, in particular (e.g., the body of the claims), are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "including" should be interpreted as "including but not limited to," etc.). While various components, methods, and devices are described in terms of "comprising" (interpreted as meaning "including but not limited to") various components or steps, compositions, methods, and devices may also "essentially comprise" or "consist of" various components and steps, and such terms should be interpreted as defining an essentially closed collection of elements. Those skilled in the art will further understand that if a specific number of claim recitations are intended to be introduced, such intent will be explicitly recited in the claim, and the absence of such recitation is not an indication that such intent is not presented.

[0064] For example, as an aid to understanding, the following appended claims may include the use of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed as implying that introducing a claim recitation with the indefinite article "a" or "an" limits any particular statement that includes such an introduced claim recitation to embodiments that include only one such statement, even when that same claim includes the introductory phrases "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should be construed to mean "at least one" or "one or more"); the same applies to the use of definite articles used to introduce claim recitations.

[0065] In addition, when a specific number of claim recitations is explicitly recited, one of ordinary skill in the art will understand that such recitation should be interpreted to mean at least the recited number (e.g., a minimum recitation of "two recitations" without other modifiers means at least two recitations, or two or more recitations). Furthermore, when a rule similar to "at least one of A, B, and C, etc." is used, such an interpretation is generally intended in the sense that one of ordinary skill in the art would understand the rule (e.g., "a system including at least one of A, B, and C" includes, but is not limited to, systems having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). In cases where a rule similar to "at least one of A, B, or C, etc." is used, such an interpretation is generally intended in the sense that one of skill in the art would understand the rule (e.g., "a system including at least one of A, B, C" includes, but is not limited to, systems having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). Furthermore, one of skill in the art will appreciate that virtually any disjunction and / or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibility of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" is understood to include the possibilities of "A" or "B" or "A and B."

[0066] Additionally, when features or aspects of the disclosure are described in a Markush group, one of skill in the art will understand that the disclosure is also thereby described in terms of any individual component or subgroup of components of that Markush group.

[0067] It will be appreciated by those of skill in the art that for any and all purposes, particularly in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges of that range. Any range listed can be readily recognized as fully descriptive and capable of dividing the same range into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range described herein can be easily broken down into a lower third, middle third, upper third, etc. Also, as will be appreciated by those of skill in the art, all terms such as "up to," "at least," etc. can refer to ranges that include the recited numbers and can then be subdivided into subranges as described above. Finally, it will be appreciated by those of skill in the art that a range includes each of the individual elements. Thus, for example, a population having 1-3 cells refers to a population having 1, 2, or 3 cells. Similarly, a population having 1-5 cells refers to a population having 1, 2, 3, 4, or 5 cells.

[0068] Various of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements thereof, each of which are intended to be encompassed by the disclosed embodiments, may subsequently be made by those skilled in the art.

Claims

1. 1. A system comprising: a first powder hopper configured to supply a first powder to the first pair of rollers; one or more first sensors, each first sensor configured to determine a characteristic of the first powder in the first powder hopper; a first feeder hopper configured to supply the first powder to the first powder hopper; and a processor in operative communication with the one or more first sensors and the first feeder hopper, the processor being configured to cause the first feeder hopper to feed the first powder to the first powder hopper in response to the characteristic of the first powder in the first powder hopper being less than a first threshold.

2. 2. The system of claim 1, wherein the first powder hopper is disposed adjacent to the first pair of rollers.

3. the one or more first sensors include a level sensor; 2. The system of claim 1, wherein the characteristic of the first powder comprises a height of the first powder within the first powder hopper.

4. the one or more first sensors include a weight sensor; The system of claim 1 , wherein the characteristic of the first powder comprises a weight of the first powder within the first powder hopper.

5. a second powder hopper configured to supply a second powder to the second pair of rollers; one or more second sensors, each second sensor configured to determine a characteristic of the second powder in the second powder hopper; and a second feeder hopper configured to feed the second powder to the second powder hopper. the processor is in operative communication with the one or more second sensors and the second feeder hopper; 2. The system of claim 1, wherein the processor is further configured to, in response to the characteristic of the second powder in the second powder hopper being less than a second threshold, cause the second feeder hopper to feed the second powder to a second powder hopper.

6. 6. The system of claim 5, wherein the second powder hopper is disposed adjacent to the second pair of rollers.

7. the one or more second sensors include a level sensor; 6. The system of claim 5, wherein the characteristic of the second powder comprises a height of the second powder within the second powder hopper.

8. the one or more second sensors include a weight sensor; The system of claim 5 , wherein the characteristic of the second powder comprises a weight of the second powder within the second powder hopper.

9. The system of claim 5 , wherein the first powder is the same as the second powder.

10. The system of claim 5 , wherein the first powder is different from the second powder.

11. The system of claim 5 , wherein the first feeder hopper is connected to the second feeder hopper.

12. 1. A method comprising: supplying a first powder from a first powder hopper to a first pair of rollers; determining a characteristic of the first powder within the first powder hopper by at least one first sensor; and in response to the characteristic of the first powder being less than a first threshold, delivering a first powder from a first feeder hopper to the first powder hopper.

13. The method of claim 12 , wherein the first powder hopper is disposed adjacent to the first pair of rollers.

14. the at least one first sensor includes a level sensor; The method of claim 12 , wherein the characteristic of the first powder comprises a height of the first powder within the first powder hopper.

15. the at least one first sensor includes a weight sensor; The method of claim 12 , wherein the characteristic of the first powder comprises a weight of the first powder within the first powder hopper.

16. supplying a second powder from a second powder hopper to a second pair of rollers; determining a characteristic of the second powder within the second powder hopper by at least one second sensor; and 13. The method of claim 12, further comprising: in response to the characteristic of the second powder being less than a second threshold, delivering a second powder from the second feeder hopper to the second powder hopper.

17. 17. The method of claim 16, wherein the second powder hopper is disposed adjacent to the second pair of rollers.

18. the at least one second sensor includes a level sensor; 17. The method of claim 16, wherein the characteristic of the second powder comprises a height of the second powder within the second powder hopper.

19. the at least one second sensor includes a weight sensor; 17. The method of claim 16, wherein the characteristic of the second powder comprises a weight of the second powder within the second powder hopper.

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