Continuous dry powder mixing system

Abstract

A continuous dry powder mixing system is provided that continuously mixes dry powder materials for dispensing a homogenous dry powder onto a surface of the web. The system includes a dry powder mixer that deagglomerates the dry powder particles and continuously mixes the dry powder particles to bind particles together in preparation for dispensing onto the surface of the web.

Description

CONTINUOUS DRY POWDER MIXING SYSTEMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 657,364, filed on June 7, 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.

[0003] One 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.

[0004] Another conventional manufacturing process used in the industry is dry powder mixing. The conventional dry powder coating system generally includes a reservoir or chamber that receives and dispenses powder particles onto a moving substrate (e.g., a current collector foil). Such dry powder coating technology can be, e.g., spreader roller coating, electrostatic deposition (ESD) coating, or the like. Commonly, dry powder mixing in these systems is performed as a batch process, which results in long mixing times.SUMMARY

[0005] In accordance with embodiments of the present disclosure, an exemplary continuous dry powder mixing system is provided. The system includes a dry powder mixer associated with a web passing through a coating chamber. The system includes afirst dry powder material introduced into the dry powder mixer. The first dry powder material includes agglomerated particles. The system includes a second dry powder material introduced into the dry powder mixer. The dry powder mixer is configured to deagglomerate the agglomerated particles of the first dry powder material into a deagglomerated dry powder. The dry powder mixer is configured to continuously mix the deagglomerated dry powder and the second dry powder material to bind the deagglomerated dry powder with the second dry powder material to produce a composite dry powder.

[0006] The dry powder mixer can be configured to transfer the composite dry powder to a dispenser for dispensing the composite dry powder onto a surface of the web passing through the coating chamber. The system can include a first dispenser and a second dispenser configured to dispense the first and second dry powder materials, respectively, into the dry powder mixer in a metered or controlled manner. The first dispenser can be configured to dispense more of the first dry powder material into the dry powder mixer than the second dry powder material dispensed by the second dispenser into the dry powder mixer.

[0007] The first dispenser can be configured to dispense a proportional amount of the first dry powder material into the dry powder mixer as the second dry powder material is dispensed by the second dispenser into the dry powder mixer. For example, a ratio of 2- to-1 can be used for dispensing the first dry powder material relative to the second dry powder material. However, it should be understood that any ratio or proportional relationship of the dry powder materials can be used. The first dry powder material and the second dry powder material can be different.

[0008] In some embodiments, the system can include one or more calendering rollers configured to densify and / or compress the composite dry powder onto the surface of the web. In some embodiments, the system can include an electrostatic coating system for directing the composite dry powder onto the surface of the web. In some embodiments, the dry powder mixer can be at least one of an acoustic mixer, a high frequency vibratory mixer, or a twin screw mixer.

[0009] In some embodiments, the system can include a third powder dispenser configured to dispense a third dry powder material into the dry powder mixer in a metered or controlled manner. The dry powder mixer can be configured to continuously mix thecomposite dry powder with the third dry powder material to produce a homogenous composite dry powder.

[0010] In some embodiments, the dry powder mixer can include multiple mixing compartments, e.g., one mixer having different mixing zones that perform either the same or different functions. For example, in some embodiments, the dry powder mixer can include multiple mixing compartments in the form of one or more twin screw mixers and / or multi-plate acoustic mixers, or a combination of different mixers, such as high impact mixer(s) and mixer(s). In some embodiments, the dry powder mixer can be a single mixer having different mixing zones, or different mixers. In some embodiments, the dry powder mixer can include at least a high impact mixing compartment and a blending or mixing compartment. The high impact mixer can be configured to deagglomerate the agglomerated particles. The mixer can be configured to continuously mix the deagglomerated dry powder and the second dry powder material to bind the deagglomerated powder with the second dry powder material to produce the composite dry powder. The system can include a pneumatic conveying system configured to transfer the composite dry powder from the mixer to a powder coating system configured to dispense the composite dry powder into the coating chamber.

[0011] In some embodiments, the high impact mixer can be a jet mill mixer. In some embodiments, the mixer can be configured to receive a third dry powder material, and the mixer can be configured to continuously mix the deagglomerated dry powder, the second dry powder material, and the third dry powder material to produce a homogenous composite dry powder. In some embodiments, the system can include high pressure air introduced into the high impact mixer to deagglomerate the agglomerated particles. The mixer can be disposed downstream of the high impact mixer.

[0012] In accordance with embodiments of the present disclosure, an exemplary method of continuous dry powder mixing is provided. The method includes introducing a first dry powder material into a dry powder mixer associated with a web passing through a coating chamber. The first dry powder material includes agglomerated particles. The method includes introducing a second dry powder material into the dry powder mixer. The method includes deagglomerating the agglomerated particles of the first dry powder material into a deagglomerated dry powder with the dry powder mixer. The method includes continuously mixing the deagglomerated dry powder and the second dry powdermaterial with the dry powder mixer to bind the deagglomerated dry powder with the second dry powder material to produce a composite dry powder.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] To assist those of skill in the art in making and using the continuous dry powder mixing system, reference is made to the accompanying figures, wherein:

[0014] FIG. 1 is a diagrammatic view of an exemplary continuous dry powder mixing system in accordance with embodiments of the present disclosure, including an acoustic style mixer;

[0015] FIG. 2 is a diagrammatic view of an exemplary continuous dry powder mixing system in accordance with embodiments of the present disclosure, including a high impact style mixer; and

[0016] FIG. 3 is a block diagram for a control system for regulating characteristics of a resulting powder of an exemplary continuous mixing and direct dry powder deposition system in accordance with embodiments of the present disclosure.

[0017] FIG. 4 shows examples of composite material after mixing as formed by an exemplary continuous dry powder mixing system in accordance with embodiments of the present disclosure.DETAILED DESCRIPTION

[0018] The process of engineering the material is key to a dry powder mixing system. In order to prepare the material using the exemplary system, the powder is first deagglomerated and subsequently continuously mixed. Agglomerations of particles often occur with bulk granular materials, including electrochemical active materials, binder materials, and conductive materials associated with manufacture of electrochemical energy storage devices according to the present disclosure. All of these materials take the form of particles, which may be in the form of agglomerates, meaning multiple primary particles interacting through relatively weak forces broken through agitation and mixing. Common nomenclature denotes the agglomerates as secondary particles and, once agitated, broken into primary particles, or sub-particles.

[0019] While processes and methods discussed herein generally function to form discrete primary particles from the sub particles of broken, stirred or agitated agglomerates, a particle as defined herein includes primary particles, secondary particles, sub particles of agglomerates, and any interaction or bonding between particles of a particular type. Stateddifferently, although clusters of primary particles, often called secondary particles or agglomerates, are generally expected to disassociate into smaller particles upon agitation, certain agglomerations may remain and nonetheless define a particle of the respective active material, binder, or conductive material, meaning particles and / or any form of sub particles thereof. A particle may therefore be broken into multiple sub particles, each of which is still a particle, nonetheless. In addition, the force applied during the agitation process may be sufficient to pulverize the agglomerated particles.

[0020] Deagglomeration can be performed in various different ways, with nonlimiting examples provided herein. For example, the powder preparation can be performed by using an acoustic mixer, as well as a high impact mixer. In the examples discussed herein, the preparation and mixing of the materials is shown. An example plating technique is shown; however there are other plating techniques that could be used. The importance of the material preparation is so that the entire operation may be achieved in a continuous manner. Plating may be achieved using calender rollers or an electrostatic deposition coating method (ESD). However, in both instances, mixing the material is performed in a continuous process after deagglomeration is achieved. A variety of materials can be used for mixing the dry powder, including but not limited to, the materials discussed in U.S. Patent Application No. 17 / 885,066, filed on August 10, 2022, which is incorporated by reference its entirety.

[0021] FIG. 1 is a diagrammatic view of an exemplary continuous mixing and direct dry powder deposition system 100 including a mixer 116. In some embodiments, the mixer 116 can be, e.g., an acoustic style mixer, a continuous style mixer (such as a twin-screw mixer), or the like. Although illustrated as a single mixer 116, it should be understood that two or more mixers could be used in series. The continuous mixing system 100 includes a dry powder mixer 116 disposed above the surface of the web 130 to be coated. Feedstock enters into the system 100 and is introduced into the mixer 116 via feedstock dispensers 102, 104 and 106 and, after mixing, is introduced onto the web 130. Although three dispensers 102-106 are shown, in some embodiments, the system 100 can include only two dispensers, or three or more dispensers, depending on the number of materials being mixed for the dry powder mixture.

[0022] Material entering feedstock dispenser 102 is material 108 (e.g., material A). Material entering feedstock dispenser 104 is material 110 (e.g., material B). Material entering feedstock dispenser 106 is material 112 (e.g., material C). Material A, material B,and material C enter the mixer 116 as powder. In some embodiments, material A can be, e.g., an electrochemically active material, such as material(s) from a family of lithium metal oxides and / or sodium metal oxides, or combinations thereof. For example, material A can be, but is not limited to, lithium nickelcobaltmanaganese oxide (LiNMCCh), sodium chromium oxide (NaCrCF), or the like. In some embodiments, material B can be, e.g., an electronically conductive material, such as material(s) from a family of carbons and / or conducting polymers. For example, material B can be, but is not limited to, carbon black, polyaniline, or the like. In some embodiments, material C can be, e.g., a binder, such as material(s) from a family of polymers. For example, material C can be, but is not limited to, polyvinylidene fluoride, polyvinylacetateester, or the like.

[0023] The substrate or web 130 is continuously passed or moved through a coating chamber 120 along web direction 132. The uncoated web 130 can be fed into the system 100 using an unwind roller 124, and one or more optional idler rollers 126, 128. As the web 130 is moved through the chamber 120, the composite powder 118 is deposited onto the web 130 to generate a dry powder coating 122 on at least one surface (e.g., the top surface) of the web 130. After coating of the web 130, the web 130 is fed by one or more idler rollers 134, 140 through calendering rollers 136, 138 for compression (with or without heat) to bind the coating onto the surface of the web 130. In some embodiments, one or more spreader rollers can be used upstream of the calendering rollers 136, 138 to evenly spread the dry powder coating 122 on the surface of the web 130 prior to compression with the calendering rollers 136, 138. A rewind roller 142 can be used to gather the coated web 130 for storage and further use.

[0024] Although illustrated as a spreader roller system, it should be understood that the dry powder mixture could similarly be fed to an electrostatic deposition (ESD) coating system. The material is continuously added via metered dispensers 102, 104 and 106 to control the amount of material to form the composite powder 118. The output of the metered dispensers 102, 104, 106 ensures that material is continuously flowing into the mixer 116. In some embodiments, the same amount of material can be added into the mixer 1 16 from each dispenser 102, 104, 106. In some embodiments, the dispensers 102, 104 and 106 can regulate or meter the amount of material being added to the mixer 116 such that different amounts of material (e.g., different volume, different weight, different rates, or the like) are added from one or more dispensers 102, 104, 106. In some embodiments, the amount of material added from each dispenser 102, 104, 106 can be continuous. Insome embodiments, the amount of material added from each dispenser 102, 104, 106 can be varied with time. In some embodiments, addition of material by each dispenser 102, 104, 106 can be simultaneous. In some embodiments, addition of materials by each dispenser 102, 104, 106 can be staggered in time. The dispensers 102, 104, 106 and mixer 116 therefore allow for a customized creation of dry powder to be mixed and dispensed onto the web 130, depending on desired specifications for the dry powder mixture and / or the web 130 coating.

[0025] The unmixed powder is initially fed or introduced to the mixer 116. In some embodiments, the mixer 116 can be, e.g., a multi-plate acoustic mixer (e.g., manufactured by Resodyn Corporation, or the like), a twin screw mixer (e.g., manufactured by Buhler, or the like), combinations thereof, or the like. The mixer 116 is continuously fed material from the dispensers 102, 104, 106 and itself continuously mixes the materials. The mixing process first (or simultaneously) deagglomerates the powder and subsequently continuously mixes the materials 114 together so that the particles can interact as desired. The mixer continuously outputs a homogenous, composite material 118 onto the web 130. Characteristics of the mixer 116 may be varied in order to optimize the requirements for the composite material 118 and ultimately the material requirements for the battery cells being produced. The ultimate structure of the composite material 118 may also be controlled by the mixer 116 characteristics as will be shown.

[0026] In some embodiments, while the mixer deagglomerates the powder particles, it may be desirable for the materials 114 to mix homogenously without adhering to each other. In some embodiments, it may be desirable for particles of one material 108 to adhere to particles of a second material 110. Particles of a third material 112 may be interstitially mixed in between the first and second material 108, 110. In some embodiments, materials 108, 110 can initially be mixed into a homogenous mixture using a first mixer 116, the homogenous mixture can be fed into a second mixer substantially similar to mixer 116 along with the material 112, and a final homogenous mixture of materials 108, 110, 112 can be formed in stages. It should be understood that for efficiency and clarify, only a single mixer 1 16 is illustrated. In some embodiments, the amplitude, frequency, and / or number of plates within the mixer 116 can be controlled or varied to achieve the desired mixture characteristics. While FIG. 1 shows that raw material 108, 110, 112 is dispersed from the top into the mixer 116, in some embodiments, material 110, 112 can be introduced in subsequent plates such that the materials 108, 1 10, 112 are mixed in stages orsequentially. In its final form, the composite powder 118 is a uniform, homogeneous mixture of the three materials 108, 110, 112. The entire mixing process (including the dispensing steps via dispensers 102, 104, 106 and the mixer 1 16) is performed continuously, resulting in a significantly faster mixing process and significantly lower energy consumption (as compared to conventional fibrilization).

[0027] The composite powder 118 is continuously deposited onto the foil web 130 such that a uniform amount of powder 118 is deposited and dispersed on the web 130. The web 130 remains in constant motion traveling in the direction 132. The foil web 130 is unwound from an unwind roller 124. The web 130 can be tensioned by idler rollers 126, 128 as it moves through and across the dry powder coating chamber 120. After the powder 118 is deposited onto the foil web 130, the coating 122 is densified by the calendering rollers 136, 138 via compression with or without heat. Compression of the powder 118 onto the web 130 with the calendering rollers 136, 138 binds the particles to each other and to the surface of the web 130. In some embodiments, prior to the calendering rollers 136, 138, one or more spreader rollers (e.g., conditioning rollers) can be used to spread and distribute the powder 118 evenly across the entire surface of the web 130 to ensure a uniform coating is creating before passage through the calendering rollers 136, 138. In some embodiments, rather than spreader roller technology, an ESD coating system can receive the mixed dry powder as input.

[0028] In some embodiments, the system 100 can include a single mixer 116 for dispensing a single homogenous composite powder 118 onto the web 130. In some embodiments, the system 100 can include duplicates of the mixer 116 to allow for different homogenous composite powders 118 to be dispensed onto the web 130 (and the underlying coating), thereby resulting in a multi-layer coating. In some embodiments, the secondary mixer can be positioned immediately after or downstream of the mixer 116 (or after spreader rollers). In some embodiments, the secondary mixer can be positioned immediately after or downstream of the calendering rollers 136, 138, and a second set of spreader rollers and calendering rollers can be used to create the second layer of coating over the underlying coating layer. The materials in the secondary mixer can be the same or different from the materials of the first mixer 116.

[0029] In some embodiments, an idler roller 134 can aid in feeding the calendering rollers 136, 138. The calendering rollers 136, 138 produce a calendered electrode 144 having a compressed dry powder coating layer. In some embodiments, another idler roller140 can aid in feeding the rewind roll 142. Continuous mixing allows the foil to be coated with dry powder without performing the mixing and deposition using the convention batch process. The amount of material compressed onto the foil web is controllable by how much material the feedstock dispensers feed into the mixer and / or the speed at which the foil web travels. The mixture itself can be determined by the relative feed rates for each feed stock dispenser. The feedstock dispenser rates may be adjusted to vary the mixture of the composited material. Customization of the dry powder coating layer is therefore permitted by the exemplary system 100.

[0030] Prior to densification, the powder coating layer 122 sits on the foil web 130 without adhering to the web 130. After densification with the calendering rollers 136, 138, the dry powder coating is adhered to the web 130 and composite powder particles 118 are bonded together via mechanical force between the coating layers and the web 130 due to the compressive forces applied to the powder coating layer 122. In some embodiments, the system 100 can include a twin screw high speed mixer in place of or supplementing the acoustic mixer 116. Like the acoustic mixer 116, material continuously enters the twin screw high speed mixer, dispenses material continuously, and deposits the compounded material onto the foil web. The twin screw high speed mixer also deagglomerates the particles before continuously mixing them. Additionally, in this example three materials are mixed to form the composite power, but it should be understood that there may be more or less materials used such that additional feedstock dispensers may be used to meter in a larger number of materials. As noted herein, these embodiments are not limited to calender roller plating of an electrode (e.g., spreader roller technology), and instead the system can be used in conjunction with an electrostatic coating system.

[0031] FIG. 2 is a diagrammatic view of a continuous mixing and direct dry powder deposition system 200 including multi-stage mixing systems. In some embodiments, the system 200 can include two or more stages of mixing. In some embodiments, the continuous mixing systems discussed herein can include multiple compartments, with each compartment performing different mixing functions. The first stage is a mixing compartment 202 which performs a high impact mixing function. In some embodiments, the mixing compartment 202 can be, e.g., a high impact mixer, or the like. As in the system of 100, system 200 can receive three materials (Material A, Material B and Material C), and continuously mixes them to produce a homogenous composite material that is delivered to a hopper 214 of the powder coating system 216. It should be understood that the system200 can mix more or less materials. In some embodiments, the system 200 can include more mixing stages, depending on the number of materials being mixed and the desired specifications for the resulting composite material. First, a high impact mixing compartment 202 is used to deagglomerate the powder material. The mixing compartment 202 then transfers the deagglomerated material to a second mixing compartment 210 (e.g., a high shear mixer) performing mixing via piping or conveyor 208. The mixing compartment 210 transfers the mixed material to the powder coating hopper 214 via a material handling system 212. In some embodiments, the material handling system 212 can be a pneumatic transfer system.

[0032] In some embodiments, the mixing compartment 202 can be a jet mill. Material A, Material B and Material C enter the high impact mixing compartment 202 via the material input feeder 204. High pressure air enters through inlet 206. The jet mill deagglomerates or disperses the powder and transfers it to the high shear mixing compartment 210. The deagglomeration and / or dispersing of the materials in the mixing compartment 202 is performed continuously. In some embodiments, Material A, B and C can enter the mixing compartment 202 together (i.e., simultaneously). In some embodiments, Material B and C can enter the mixing compartment 202 for deagglomeration / dispersion, and the homogenous mixture of Materials B and C can be subsequently transferred to the high shear mixing compartment 210 where Material A is introduced for mixing with the previously mixed composite of Materials B and C. In such embodiments, an inlet (similar to input feeder 204) can be used for the mixing compartment 210 for introduction of one or more materials. In some embodiments, the mixing compartment 202 can mix each material separately such as one after the other (or sequentially), or can mix one material with all materials at the same time (or concurrently). It is understood that more mixing compartments can be included in system 200 to achieve the desired mixed composite characteristics.

[0033] In some embodiments, one or both of the high shear mixing compartments 202, 210 can be, e.g., a longitudinally oriented twin screw mixer, or the like. In some embodiments, one or both of the high shear mixing compartments 202, 210 can be, e.g., a horizontally configured flight mixing element, to mix the dry powder ingredients in a continuous fashion. In some embodiments, the horizontally configured flight mixing element can be, e.g., a Horizontal Kneading Machine available from IKA-Werke GmbH & Co. KG (https : / / www.ikaprocess.com / en / Products / Kneading-machines-Kneaders-cph-17 / Continuous-kneader-csb-KoKn / ). In some embodiments, one or both of the mixing compartments 202, 210 can be, e.g., a continuous resonance mixer coupled with a dry powder scatterer in-between to facilitate mixed dry powder dosing into the dry powder coater. Although two mixing compartments 202, 210 are illustrated, it should be understood that the system 200 can include two or more such mixing compartments as needed to achieve the desired dispersion and / or mixing of materials.

[0034] In some embodiments, material may be introduced sequentially into the mixing compartment 202 such that the mixing compartment 202 first disperses Material A. Once dispersed, Material B can be introduced into the mixing compartment 202 to disperse and mix Material B with Material A. Finally, Material C can be introduced into the mixing compartment 202 to disperse and mix Material C with the mixture of Materials A and B. In some embodiments, all materials can be dispersed in mixing compartment 202 simultaneously. In some embodiments, the amount of each material introduced into the mixing compartment 202 can be metered to allow for customization of the resulting homogenous mixture for dry powder coating.

[0035] Thus, the system 200 can also disperse powder components (Material B and Material C) either together (concurrently) or separately (sequentially) using a high impact mixer, such as an air jet mill of mixing compartment 202. Components or Materials B and C enter the air jet mill though the input feeder 204. High pressure air enters the jet mill via inlet 206. The jet mill directly discharges the components or Materials B and C into an intensive mixing compartment 210 that already contains powder component or Material A, and mixes all three components until a homogeneous mixture is achieved. The mixing compartment 202 applies high impact mixing for deagglomerating the particles, whereas the intensive mixing compartment 210 applies high shear mixing continuously to mix the particles. Both the mixing compartments 202, 210 operate continuously to generate the resulting mixture. The high shear mixer (mixing compartment 210) breaks the particles into small parts. In some embodiments, the smaller particles may coat the larger particles.

[0036] The mixture produced in the intensive mixing compartment 210 is transferred via material handling system 212 to the input hopper 214, which dispenses the dry powder mixture onto the web 224 via a coating system 216. In some embodiments, the material handling system 212 can be a pneumatic conveying system. The homogenous dry power mixture is dispensed from the hopper 214 into the coating system 216. The powder is dispensed from the system 216 to uniformly coat a foil web 224, and the powder coating isimpressed onto the foil web 224 with a calendering roller system (not shown, but similar to the calendering unit of FIG. 1). The continuous mixing operation of the system 200 allows for a significantly faster mixing process and significantly lower energy consumption as compared to conventional mixing processes.

[0037] The system 200 generally uses a substrate or web 224 that is continuously passed through a coating chamber 218. The web 224 is fed into the system 200 using an unwind roller 220 and a dry powder coating 222 is applied. The powder coating 222 is densified and passes through calendering rollers (not shown) and wound back onto a rewind spool (not shown). The densification process can be substantially similar to the one discussed with respect to system 100, including the use of spreader and calendering rollers. The powder material is dispensed onto the foil web 224 by a powder coating system 216. The powder coating system 216 lays down or dispenses a uniform layer of powder onto the foil web 224 substrate. The powder to be coated onto the foil web 224 is a homogenous composite of two or more materials. The two or more powders are mixed by a series of mixers and then transferred to the powder coating system 216. As in other examples, an electrostatic deposition coating method can be used for plating the foil in combination with the system 200.

[0038] FIG. 3 shows a block diagram for a control system 300 for regulating characteristics of a resulting dry powder of the continuous mixing and direct dry powder deposition system discussed herein. Controlling the material and preparing it for mixing and ultimate plating is an important part of the process. One or more mixers 302 are used to mix the materials and to deagglomerate the powder. The mixer outputs material that is then evaluated for its characteristics 304. For example, the system can include a control feedback loop that evaluates one or more properties or characteristics 304 of the dry powder mixture with sensors to determine if adjustments to the mixing process are needed. In some embodiments, the control system can be automated and can operate substantially in realtime, such that regulation of the mixing process can be performed in substantially real-time based on the results of the evaluation.

[0039] The powder characteristics that can be evaluated by the control system to ensure powder mixing effectiveness are as follows: bulk density 320, TAP density 322, cohesive index 324, angle of repose 326, morphology SEM analysis 328, particle size distribution 330, powder conductivity 332, combinations thereof, or the like. These characteristics are analyzed and fed into a computer system (e.g., a processing device) that automaticallyadjusts the mixer operational characteristics to achieve the desired target characteristics of the mixture. For an acoustic style mixer, the computer can control mixer settings, e.g., the acoustic frequency 310, the acoustic force 312, vibration length 314, mixing time 316, combinations thereof, or the like. For a twin screw style mixer, the computer can control mixer settings, e.g., the mass flow, temperature, screw speed, combinations thereof, or the like. The evaluation can be performed under real-time control or can be used to evaluate material preproduction. The mixer 302 shown may be the mixer 116 in FIG. 1 , or may be the mixing compartment 202 from FIG. 2, or the mixing compartment 210 from FIG. 2.

[0040] FIG. 4 show examples of a composite material after mixing. In particular, FIG. 4 illustrates several dispersion patterns of particles 401 A, 40 IB, 401 C of ingredient particles in a well-mixed composite electrode powder mixture through dry mixing. Ingredient particles include active material (AM) particles, binder, and conductive particles; however in some configurations, conductive material is not needed in the composite electrode, as will be apparent in the discussion below. In general, AM particles 411 are the largest, binder particles 412 are smaller but varied, and conductive particles 413 being of the smallest range. However, in particular implementations, sizes and size relationships may vary widely.

[0041] In particle 401 A, the binder 412 either has a large sub particle size or is in the form of agglomerates. The active material particles 411 keep their original morphology during dry mixing. In the static powder form, all particles are well dispersed but there exist no strong interactions between AM particles 411, binder 412, and CB (conductive) particles 413.

[0042] Particle 40 IB shows that the binder 412 agglomerates are broken in the mixing process and the sub particle size is smaller than the active material particles 411. The active material particles 411 keep their original morphology during dry mixing. As with 401 A, at the static powder form, the particles 411, 412 and 413 may be well dispersed but there exist no strong interaction forces between AM, binder, and CB particles.

[0043] Particle 401C depicts a composite particle where the binder agglomerates are broken in the mixing process and the sub particle 412 size is smaller than the active material particles 411. The active material particles 411 remain in their original morphology during mixing. In the static powder form, binder 412 particles and conductive particles 413 are discretely coated on the surface of active material particles 411 via surface fusion, Van DerWaal attraction forces, or a variety of potential physical interactions and chemical bonds. The composite particles 401C are adapted for electrostatic deposition onto a current collector substrate based on the sub particles of the binder, agitated to break down agglomerates, and the interaction forces are sufficient to withstand separation forces induced from material handling, electrostatic deposition and post-deposition handling, onto a substrate for maintaining the morphology of the composite particle 401C.

[0044] A variety of AM particle and composite particle formulations may be achieved using the exemplary systems and methods. It should be noted of the distinction between the ingredient particles of AM, binder and conductive materials, generally obtained as a homogenous bulk granular material, and the formed composite particle formed from particle to particle interaction forces for electrostatic deposition. In an example arrangement, the active material is formed from transition metal oxides for an electrochemical energy storage device as cathode material.

[0045] 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.

Claims

CLAIMS:

1. A continuous dry powder mixing system, comprising: a dry powder mixer associated with a web passing through a coating chamber; a first dry powder material introduced into the dry powder mixer, wherein the first dry powder material includes agglomerated particles; and a second dry powder material introduced into the dry powder mixer; wherein the dry powder mixer is configured to deagglomerate the agglomerated particles of the first dry powder material into a deagglomerated dry powder; and wherein the dry powder mixer is configured to continuously mix the deagglomerated dry powder and the second dry powder material to bind the deagglomerated dry powder with the second dry powder material to produce a composite dry powder.

2. The continuous dry powder mixing system of claim 1, wherein the dry powder mixer is configured to transfer the composite dry powder to a dispenser for dispensing the composite dry powder onto a surface of the web passing through the coating chamber.

3. The continuous dry powder mixing system of claim 1, comprising a first dispenser and a second dispenser configured to dispense the first and second dry powder materials, respectively, into the dry powder mixer in a metered or controlled manner.

4. The continuous dry powder mixing system of claim 3, wherein the first dispenser is configured to dispense more of the first dry powder material into the dry powder mixer than the second dry powder material dispensed by the second dispenser into the dry powder mixer.

5. The continuous dry powder mixing system of claim 3, wherein the first dispenser is configured to dispense a proportional amount of the first dry powder material into the dry powder mixer as the second dry powder material is dispensed by the second dispenser into the dry powder mixer.

6. The continuous dry powder mixing system of claim 1, wherein the dry powder mixer includes multiple mixing compartments.

7. The continuous dry powder mixing system of claim 2, comprising a calenderingroller configured to densify and / or compress the composite dry powder onto the surface of the web.

8. The continuous dry powder mixing system of claim 2, comprising an electrostatic coating system for directing the composite dry powder onto the surface of the web.

9. The continuous dry powder mixing system of claim 1 , wherein the dry powder mixer is at least one of an acoustic mixer, a high frequency vibratory mixer, or a twin screw mixer.

10. The continuous dry powder mixing system of claim 1, comprising a third powder dispenser configured to dispense a third dry powder material into the dry powder mixer in a metered or controlled manner.

11. The continuous dry powder mixing system of claim 10, wherein the dry powder mixer is configured to continuously mix the composite dry powder with the third dry powder material to produce a homogenous composite dry powder.

12. The continuous dry powder mixing system of claim 1, wherein the dry powder mixer includes a high impact mixer and a mixer.

13. The continuous dry powder mixing system of claim 12, wherein the high impact mixer is configured to deagglomerate the agglomerated particles.

14. The continuous dry powder mixing system of claim 13, wherein the mixer is configured to continuously mix the deagglomerated dry powder and the second dry powder material to bind the deagglomerated powder with the second dry powder material to produce the composite dry powder.

15. The continuous dry powder mixing system of claim 12, comprising a pneumatic conveying system configured to transfer the composite dry powder from the mixer to a powder coating system configured to dispense the composite dry powder into the coating chamber.

16. The continuous dry powder mixing system of claim 12, wherein the high impact mixer is a jet mill mixer.

17. The continuous dry powder mixing system of claim 12, wherein the mixer is configured to receive a third dry powder material, and wherein the mixer is configured to continuously mix the deagglomerated dry powder, the second dry powder material, and the third dry powder material to produce a homogenous composite dry powder.

18. The continuous dry powder mixing system of claim 12, comprising high pressureair introduced into the high impact mixer to deagglomerate the agglomerated particles.

19. The continuous dry powder mixing system of claim 12, wherein the mixer is disposed downstream of the high impact mixer.

20. A method of continuous dry powder mixing, the method comprising: introducing a first dry powder material into a dry powder mixer associated with a web passing through a coating chamber, wherein the first dry powder material includes agglomerated particles; introducing a second dry powder material into the dry powder mixer; deagglomerating the agglomerated particles of the first dry powder material into a deagglomerated dry powder with the dry powder mixer; and continuously mixing the deagglomerated dry powder and the second dry powder material with the dry powder mixer to bind the deagglomerated dry powder with the second dry powder material to produce a composite dry powder.

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