Method and apparatus for the dry, solvent free manufacture of electrodes using powders

Abstract

A system for dry manufacturing an electrode for an energy storage device includes a substrate configured to move in a feed direction. The system also includes a powder delivery system configured to deposit a dry powder onto a surface of the substrate. The powder delivery system or a patterning roller is configured to form a plurality of laterally adjacent lanes of the dry powder on the surface of the substrate. In addition, the system includes an upper spreading roller positioned downstream of the powder delivery system relative to the feed direction. The upper spreading roller has a central axis and a radially outer cylindrical surface. The radially outer cylindrical surface of the upper spreading roller is configured to directly contact and spread the plurality of laterally adjacent lanes of the dry powder on the substrate to form a spread layer of the dry powder on the substrate.

Description

METHOD AND APPARATUS FOR THE DRY, SOLVENT FREE MANUFACTURE OF ELECTRODES USING POWDERSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit of U.S. provisional patent application Serial No. 63 / 636,246 filed April 19, 2024, and entitled "Methods and Apparatus for the Dry, Solvent Free Manufacture of Electrodes Using Powders," which is hereby incorporated herein by reference in its entirety for all purposes.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.BACKGROUND

[0003] The disclosure relates generally to manufacturing methods and apparatus. More particularly, the disclosure relates to methods and apparatus for dry manufacturing electrodes for energy storage devices such as batteries (e.g., lithium ion batteries, sodium ion batteries, solid state batteries, etc.).

[0004] Li-ion battery (LIB) production capacity is projected to grow significantly in the coming years. Consequently, it is anticipated that about a 4x increase of manufacturing capacity will need to be added over the next decade to meet the demand for Li-ion batteries. Argonne National Lab has estimated that the battery electrode manufacturing equipment alone may cost about $66 million for each 5 GWh plant. To build up 1 ,000 GWh of new capacity, 200 such plants need to be constructed.

[0005] The rapid growth in battery manufacturing imposes significant impacts on energy consumption and greenhouse gas emissions. For example, a current 5GWh Li-ion battery plant consumes about 565 GWh / year of electricity. In particular, conventional methods for manufacturing electrodes for Li-ion batteries utilize slurry casting techniques that require energy intensive drying, environmentally hazardous solvents, and a relatively large footprint.BRIEF SUMMARY OF THE DISCLOSURE

[0006] Embodiments of systems for dry manufacturing electrodes for energy storage devices are disclosed herein. In one embodiment, a system for dry manufacturing an electrode for an energy storage device comprises a substrate configured to move in afeed direction. The system also comprises a powder delivery system configured to deposit a dry powder onto a surface of the substrate. The powder delivery system or a patterning roller is configured to form a plurality of laterally adjacent lanes of the dry powder on the surface of the substrate. In addition, the system comprises an upper spreading roller positioned downstream of the powder delivery system relative to the feed direction. The upper spreading roller has a central axis and a radially outer cylindrical surface. The radially outer cylindrical surface of the upper spreading roller is configured to directly contact and spread the plurality of laterally adjacent lanes of the dry powder on the substrate to form a spread layer of the dry powder on the substrate. Further, the system comprises a pair of compaction rollers comprising an upper compaction roller and a lower compaction roller positioned below the upper compaction roller. The upper compaction roller and the lower compaction roller are positioned downstream of the upper spreading roller relative to the feed direction. Each compaction roller has a central axis and a radially outer cylindrical surface. The radially outer cylindrical surface of the upper compaction roller is configured to directly contact and compress the spread layer of the dry powder on the substrate to form the electrode on the surface of the substrate.

[0007] In another embodiment, a system for dry manufacturing an electrode for an energy storage device comprises a substrate configured to move in a feed direction. The system also comprises a powder delivery system configured to deposit a dry powder onto a surface of the substrate. In addition, the system comprises a spreading roller positioned downstream of the powder delivery system relative to the feed direction. The spreading roller has a central axis and a radially outer cylindrical surface. The radially outer cylindrical surface of the spreading roller is configured to directly contact and spread the dry powder on the substrate to form a spread layer of the dry powder on the substrate. A coefficient of friction pSubstrate-Powder between the substrate and the dry powder is greater than a coefficient of friction pSroiier-Powder between the spreading roller and the dry powder. Further, the system comprises a compaction roller positioned downstream of the spreading roller relative to the feed direction. The compaction roller has a central axis and a radially outer cylindrical surface. The radially outer cylindrical surface of the compaction roller is configured to directly contact and compress the spread layer of the dry powder on the substrate to form the electrode on the surface of the substrate.

[0008] Embodiments of methods for dry manufacturing electrodes for energy storage devices are disclosed herein. In one embodiment, a method for dry manufacturing an electrode for an energy storage device comprises (a) depositing a dry powder onto a surface of a substrate moving in a feed direction. The method also comprises (b) transporting the dry powder on the substrate beneath a spreading roller to spread the dry powder into a spread layer of the dry powder on the substrate after (a). A relative speed Vrei between the substrate and the upper spreading roller at a point of contact of the upper spreading roller with the dry powder is greater than or equal to 0 m / min and less than or equal to 50.0 m / min. In addition, the method comprises (c) transporting the spread layer of the dry powder on the substrate beneath a compaction roller to compress the spread layer of the dry powder into the electrode on the surface of the substrate after (b).

[0009] In another embodiment, a method for dry manufacturing an electrode for an energy storage device comprises (a) depositing a dry powder onto a surface of a substrate moving in a feed direction. The method also comprises (b) forming at least one void in the dry powder on the surface of the substrate during or after (a). Each void is devoid of the dry powder. In addition, the method comprises (c) contacting and spreading the dry powder on the surface of the substrate with a spreading roller after (b) to move at least some of the dry powder laterally into each void and form a spread layer of the dry powder on the surface of the substrate. Further, the method comprises (d) compressing the spread layer of the dry powder into the electrode on the surface of the substrate after (c).

[0010] Embodiments described herein comprise a combination of features and characteristics intended to address various shortcomings associated with certain prior devices, systems, and methods. The foregoing has outlined rather broadly the features and technical characteristics of the disclosed embodiments in order that the detailed description that follows may be better understood. The various characteristics and features described above, as well as others, will be readily apparent to those skilled in the art upon reading the following detailed description, and by referring to the accompanying drawings. It should be appreciated that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes as the disclosed embodiments. It should also be realized that such equivalent constructions do not depart from the spirit and scope of the principles disclosed herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] For a detailed description of various exemplary embodiments, reference will now be made to the accompanying drawings in which:

[0012] FIG. 1 is a schematic side view an embodiment of a system for drymanufacturing electrodes for energy storage devices in accordance with principles described herein;

[0013] FIG. 2 is an enlarged schematic partial perspective view of the system of FIG.1 illustrating the substrate, the powder delivery system, the pre-shaping roller, and the patterning roller of FIG. 1 ;

[0014] FIG. 3A is a schematic view of an exemplary micro-particle and a plurality of exemplary nano-particles that can be used to form the dry powder of FIG. 1 ;

[0015] FIG. 3B is a schematic view of an exemplary nano-particle coated micro-particle formed from the exemplary micro-particle and exemplary nano-particles of FIG. 3A;

[0016] FIG. 3C is a schematic view of an exemplary pair of nano-particle coated microparticles formed from the exemplary micro-particle and exemplary nano-particles of FIG. 3A;

[0017] FIG. 4 is an enlarged schematic partial front view of the system of FIG. 1 illustrating the patterning roller of FIG. 1 forming a plurality of discrete laterally adjacent, shaped lanes of the dry powder and a plurality of voids laterally positioned between each pair of laterally adjacent lanes;

[0018] FIG. 5 is an enlarged schematic partial front view of the plurality of discrete laterally adjacent, shaped lanes of the dry powder and the plurality of voids formed by the patterning roller of FIG. 4;

[0019] FIG. 6 is an enlarged schematic partial front view of the patterning roller of FIG. 4 spaced apart from the substrate to form a plurality of laterally adjacent, shaped lanes of the dry powder and a plurality of voids on an upper portion of a pre-spread layer of the dry powder;

[0020] FIG. 7 is an enlarged schematic partial front view of the plurality of laterally adjacent, shaped lanes of the dry powder and a plurality of voids laterally positioned between each pair of laterally adjacent lanes formed on the upper portion of the prespread layer of the dry powder by the patterning roller of FIG. 6;

[0021] FIGS. 8-10 are schematic partial front views of alternative embodiments of patterning rollers in accordance with principles described herein for forming laterallyadjacent, shaped lanes of the dry powder and a plurality of voids laterally positioned between each pair of laterally adjacent lanes;

[0022] FIG. 11 is an enlarged schematic partial perspective view of an embodiment of a system for dry-manufacturing electrodes for energy storage devices in accordance with principles described herein illustrating the substrate, the powder delivery system, and the pre-shaping roller;

[0023] FIG. 12 is a schematic side view of an embodiment of a spreading roller in accordance with the principles described herein;

[0024] FIG. 13 is a schematic view of an embodiment of a method for drying manufacturing electrodes for energy storage devices in accordance with principles described herein;

[0025] FIG. 14 is a schematic side view of an embodiment of a system for drymanufacturing electrodes for energy storage devices in accordance with principles described herein;

[0026] FIG. 15 is a schematic side view of an embodiment of a system for drymanufacturing electrodes for energy storage devices in accordance with principles described herein;

[0027] FIG. 16 is a schematic partial side view of the system of FIG. 1 illustrating the spreading rollers and the substrate;

[0028] FIG. 17 is a graph of the spread dry powder uniformity as a function of relative speed for the tests performed in accordance with Example 1 ;

[0029] FIG. 18 is a graph illustrating the quality of the spread dry powder uniformity at various combinations of the speed of the upper spreading roller and the speed of the substrate for the tests performed in accordance with Example 1 ;

[0030] FIGS. 19A and 19B illustrate the spread powder uniformity after the pre-shaping roller and after the spreading roller, respectively, for the tests performed in accordance with Example 2 without the patterning roller; and

[0031] FIGS. 20A and 20B illustrate the spread powder uniformity after the pre-shaping roller and the patterning roller, and after the spreading roller, respectively, for the tests performed in accordance with Example 2 with the patterning roller.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The following discussion is directed to various exemplary embodiments. However, one skilled in the art will understand that the examples disclosed herein havebroad application, and that the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment.

[0033] Certain terms are used throughout the following description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function. The drawing FIGS, are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness.

[0034] Unless the context dictates the contrary, all ranges set forth herein should be interpreted as being inclusive of their endpoints, and open-ended ranges should be interpreted to include only commercially practical values. Similarly, all lists of values should be considered as inclusive of intermediate values unless the context indicates the contrary.

[0035] In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to... .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct engagement between the two devices, or through an indirect connection that is established via other devices, components, nodes, and connections. In addition, as used herein, the terms “axial” and “axially” generally mean along or parallel to a particular axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to a particular axis. For instance, an axial distance refers to a distance measured along or parallel to the axis, and a radial distance means a distance measured perpendicular to the axis. As used herein, the terms “approximately,” “about,” “substantially,” and the like mean within 10% (i.e., plus or minus 10%) of the recited value. Thus, for example, a recited angle of “about 80 degrees” refers to an angle ranging from 72 degrees to 88 degrees.

[0036] As described above, conventional methods for manufacturing electrodes for energy storage devices (e.g., Li-ion batteries, sodium ion batteries, all solid state batteries, etc.) typically have high energy demands, rely on environmentally hazardous solvents, may require a relatively large footprint, and may not be scalable for large scaleproduction. Accordingly, embodiments of systems and methods disclosed herein for manufacturing electrodes for energy storage devices are directed to solvent free (or “dry”) techniques that are environmentally friendly, and that offer the potential to reduce energy consumption and greenhouse gas emissions. For example, it is estimated that dry electrode manufacturing systems and methods disclosed herein may offer up to about a 40% reduction in electricity consumption as compared to the conventional slurry casting technology for manufacturing electrodes for Li-ion batteries. In particular, switching from the conventional slurry casting techniques to embodiments of dry electrode manufacturing systems and methods as described herein offers the potential to reduce the annual electricity consumption by 226GWh and CO2 emission of 94,000 tons for a 5GWh Li-ion battery plant. Based on the projected Li-ion battery production of 1 ,300GWh in 2030, the annual reduction of electricity consumption and CO2 emissions may be 58,760 GWh and 24,440,00 tons, respectively, via switching to dry, solvent free electrode manufacture systems and methods as described herein. Much of these reductions are due to reduced energy usage by eliminating requirements for solvent drying and solvent recovery. Although these estimates are based on Li-ion battery manufacturing, it is expected that the manufacturing of all solid-state batteries will follow a similar trend.

[0037] Referring now to FIG. 1 , an embodiment of a system 100 for dry manufacturing electrodes for energy storage devices such as batteries (e.g., Li-ion batteries, solid-state batteries, etc.) is shown. More specifically, system 100 produces a continuous sheet or layer of electrode material 101 on a web or substrate 105. The electrode material 101 is formed from a dry powder 135 that is deposited directly onto the substrate 105 and mechanically processed by system 100. It is to be understood that powder 135 is “dry,” meaning it does not include any solvent. The electrode material 101 and substrate 105 can be cut as desired to produce a plurality of individual electrodes for use in energy storage devices. Accordingly, for purposes of clarity and further explanation, electrode material 101 may also be referred to herein as electrode 101.

[0038] In this embodiment, system 100 includes an unwinding or supply roller 110, a winding or receiving roller 120 horizontally spaced from the supply roller 110, a powder supply or delivery system 130, a pre-shaping roller 140, a patterning roller 150 horizontally spaced from the pre-shaping roller 140, a pair of vertically arranged spreading rollers 160, 161 horizontally spaced from patterning roller 150, a pair of vertically arranged compaction rollers 170, 171 horizontally spaced from the spreadingrollers 160, 161 , and a plurality of horizontally spaced web-stabilizing devices 180. Supply roller 110 generally provides a continuous sheet of substrate 105 on which electrode 101 is formed with system 100. In general, substrate 105 can be unwound from supply roller 110, or provided by another roller (not shown) and passed over supply roller 110 to the remainder of system 100. Supply roller 110 rotates in a rotational direction 111 about a central axis 115 to supply substrate 105 in a generally horizontal feed direction 106 through system 100. As shown in the side view of FIG. 1 , rotational direction 111 is counterclockwise and feed direction 106 is to the left. In embodiments described herein, substrate 105 is fed from supply roller 110 and moved in feed direction 106 at a feed rate or speed greater than 0.0 m / min and less than or equal to 120.0 m / min. For purposes of clarity and further explanation, the terms “upstream” and “downstream” are used to refer to positions of different components of system 100 relative to feed direction 106.

[0039] Receiving roller 120 is downstream of supply roller 110 and generally receives the continuous sheet of substrate 105 and electrode 101 formed thereon. Substrate 105 and electrode 101 can be wound onto receiving roller 120, or passed over receiving roller 120 to another roller (not shown). Receiving roller 120 rotates in a rotational direction 121 about a central axis 125 to receive substrate 105 and electrode 101 along the generally horizontal feed direction 106. As shown in FIG. 1 , rotational direction 121 is counterclockwise, and thus, rotational directions 111 , 121 of supply roller 110 and receiving roller 120, respectively, are the same. As previously described, in embodiments described herein, substrate 105 is moved in feed direction 106 at a feed rate or speed ranging greater than 0.0 m / min and less than or equal to 120.0 m / min, and thus, substrate 105 and electrode 101 formed thereon are received by receiving roller 120 at that same rate.

[0040] Referring still to FIG. 1 , powder delivery system 130, pre-shaping roller 140, patterning roller 150, spreading rollers 160, 161 , compaction rollers 170, 171 , and webstabilizing devices 180 are positioned between supply roller 110 and receiving roller 120. These components of system 100 are generally horizontally arranged side-by- side. More specifically, powder delivery system 130 is horizontally positioned between supply roller 110 and pre-shaping roller 140, patterning roller 150 is horizontally positioned between pre-shaping roller 140 and spreading rollers 160, 161 , spreading rollers 160, 161 are horizontally positioned between compaction rollers 170, 171 and patterning roller 150, and compaction rollers 170, 171 are horizontally positionedbetween winding roller 120 and spreading rollers 160, 161. Thus, powder delivery system 130 is downstream of supply roller 110, pre-shaping roller 140 is downstream of powder delivery system 130, patterning roller 150 is downstream of pre-shaping roller 140, spreading rollers 160, 161 are downstream of patterning roller 150, compaction rollers 170, 171 are downstream of spreading rollers 160, 161 , and receiving roller 120 is downstream of compaction rollers 170, 171. In this embodiment, one web-stabilizing device 180 is horizontally positioned between supply roller 110 and spreading rollers 160, 161 , and the other web-stabilizing device 180 is horizontally positioned between spreading rollers 160, 161 and compaction rollers 170, 171.

[0041] Although one pre-shaping roller 140, one patterning roller 150, one pair of spreading rollers 160, 161 , and one pair of compaction rollers 170, 171 are shown in system 100 of FIG. 1 , it should be appreciated that in other embodiments, multiple preshaping rollers 140, one or more pairs of pre-shaping rollers 140, one or more patterning roller(s) 150, two or more pairs of serially spreading rollers (e.g., spreading rollers 160, 161 ), two or more pairs of serially arranged compaction rollers (e.g., compaction rollers 170, 171 ), or combinations thereof may be provided with each spreading roller positioned downstream of each patterning roller (e.g., one or more patterning rollers 150) and each pre-shaping roller(s) (e.g., one or more pre-shaping rollers 140); and with each compaction roller (e.g., compaction rollers 170, 171) positioned downstream of each spreading roller (e.g., one or more pairs of spreading rollers 160, 161 ). In addition, system 100 shown in FIG. 1 includes the same number of pre-shaping roller(s) 140, patterning roller(s) 150, pairs of spreading rollers 160, 161 , and pairs of compaction rollers 170, 171 (one pre-shaping roller 140, one patterning roller 150, one pair of spreading rollers 160, 161 , and one pair of compaction rollers 170, 171), however, in other embodiments, the number of pre-shaping rollers (e.g., pre-shaping rollers 140), the number of patterning rollers (e.g. patterning rollers 150), the number of pairs of spreading rollers (e.g., spreading rollers 160, 161 ), and the number of pairs of compaction rollers (e.g., compaction rollers 170, 171) may be different (e.g., one preshaping rollers 140, one pair of spreading rollers 160, 161 and multiple pairs of compaction rollers 170, 171 , etc.). Although only one powder delivery system 130 is shown in FIG. 1 , multiple powder delivery systems may be provided before or after any of the pre-shaping rollers, patterning rollers, spreading rollers, and compaction rollers. Still further, although patterning roller 150 is downstream of pre-shaping roller 140 in the embodiment shown in FIG. 1 , in other embodiments, pre-shaping roller 140 may bepositioned downstream of patterning roller 150 relative to feed direction 106 with the understanding both rollers 140, 150 are positioned between powder delivery system 130 and spreading rollers 160, 161. Still further, in some embodiments, patterning roller 150 is not provided.

[0042] As schematically shown in FIG. 1 , in this embodiment, substrate 105 comprises a conductive base 107 in the form of a sheet of conductive material and a friction enhancing treatment 108 applied to the surface of base 107 onto which electrode 101 is formed (e.g., the upper surface of base 107 as shown in FIG. 1 ). In general, base107 can be a sheet of any suitable conductive material including, without limitation, a sheet of aluminum foil or a sheet of copper foil. In general, friction enhancing treatment108 on the surface of base 107 can be a material coating or texture applied to the surface of base 107. In embodiments where friction enhancing treatment 108 is a coating applied to the surface of base 107, the coating can be any suitable material for (i) increasing the coefficient of friction between the surface of substrate 105 and dry powder 135 deposited thereon, and (ii) increasing the adhesion between electrode 101 (formed from dry powder 135) and substrate 105 including, without limitation, a carbonbased coating or a polyvinylidene fluoride (PVDF) coating. Examples of carbon-based materials that can be used for a carbon-based coating include, without limitation, carbon black, layered graphite, carbon nanotubes, graphene, graphene oxide, reduced graphene oxide, amorphous carbon, doped carbon, carbon-metal composite, etc. In one exemplary embodiment, base 107 is aluminum foil and friction enhancing treatment 108 is a carbon-based coating. In embodiments where friction enhancing treatment 108 is a texture applied to the surface of base 107, the texture can be any suitable texture for (i) increasing the coefficient of friction between the surface of substrate 105 and dry powder 135, (ii) increasing the adhesion between electrode 101 (formed from dry powder 135) and substrate 105, and (iii) increasing the interaction between the surface of substrate 105 and dry powder 135 including, without limitation, a laser etched, laser induced texture, or the like.

[0043] Substrate 105 has a thickness T s measured perpendicularly between its upper and lower surfaces. In embodiments, described herein, the thickness T s of substrate 105 ranges from 1.0 micron to 200.0 micron, and alternatively ranges from 1.0 micron to 30.0 micron. As best shown in FIG. 2, substrate 105 has a uniform width W105 measured perpendicular to feed direction 106 between the parallel, lateral sides or edges of substrate 105.

[0044] Referring now to FIGS. 1 and 2, powder delivery system 130 includes a powder feeder 131 and a powder de-lumping device 134 positioned below powder feeder 131. Powder feeder 131 generally feeds or delivers a dry powder 135 that is used to form electrode 101 on substrate 105. In general, powder feeder 131 can be any suitable device for controllably feeding a dry powder such as a volumetric feeder (e.g., as screw feeder), a vibratory feeder, a gravimetric feeder (e.g., as loss-in-weight feeders), a hopper-based gravity feeder, or the like. Powder feeder 131 deposits dry powder 135 onto the upper surface of substrate 105, which carries and moves dry powder 135 in feed direction 106 to pre-shaping roller 140, patterning roller 150, spreading rollers 160, 161 and then compaction rollers 170, 171. As best shown in FIG. 2, in this embodiment, powder feeder 131 includes a hopper or receptacle 132 and an output nozzle 133 extending downward from hopper 132. Hopper 132 generally holds a batch or load of dry powder 135, and output nozzle 133 receives dry powder 135 held by hopper 132 and supplies dry powder 135 to substrate 105 at a desired feed rate (e.g., mass feed rate). For most electrode manufacturing operations, the mass feed rate of dry powder 135 onto substrate 105 by powder delivery system 130 is greater than 0.0 gram / s and less than or equal to 300.0 gram / s per 100 mm of width Wws of substrate 105.

[0045] De-lumping device 134 is positioned between output nozzle 133 of powder feeder 131 and substrate 105 to break-up any clumps in dry powder 135 before it is deposited onto substrate 105. In this embodiment, de-lumping device 134 is an ultrasonic sieve, and more specifically, an ultrasonic sieve that vibrates at a frequency of 33-37 kHz and has a sieve mesh size ranging from 200 pm to 40 pm. Thus, dry powder 135 exits nozzle 133 and passes through de-lumping device 134, which breaks up any clumps of dry powder 135 before dry powder 135 is deposited on substrate 105. As will be described in more detail below, although powder delivery system 130 includes a single output nozzle 133 in the embodiment shown in FIG. 2, in other embodiments, the powder delivery system (e.g., delivery system 130) includes a plurality of laterallyspaced output nozzles (e.g., output nozzles 133).

[0046] As shown in FIGS. 1 and 2 and described in more detail below, pre-shaping roller 140 flattens and spreads dry powder 135 deposited on substrate 105 by powder delivery system 130 into a pre-spread layer 136 upstream of patterning roller 150. Next, patterning roller 150 receives the pre-spread layer 136 of dry powder 135, and converts at least a portion of the pre-spread layer 136 of dry powder 135 into a plurality of shaped parallel lanes 137 of dry powder 135 downstream of pre-shaping roller 140. Then,spreading rollers 160, 161 receive the shaped parallel lanes 137 of dry powder 135 (which may be discrete lanes 137 or lanes 137 disposed along the upper portion of prespread layer 136) downstream of patterning roller 150 and uniformly spreads the lanes 137 (and any underlying pre-spread layer 136 of dry powder 135) to form a continuous spread layer 139 of dry powder 135 on substrate 105. Next, compaction rollers 170, 171 compact the spread layer 139 of dry powder 135 on substrate 105 downstream of spreading rollers 160, 161 to form electrode 101 on substrate 105.

[0047] In embodiments in which electrode 101 is manufactured for use in Li-ion batteries, dry powder 135 includes an active material, a binder, and a conductive additive (each in a powder form). Optionally, one or more solid state electrolytes (also in a powder form) can be included in dry powder 135 when electrode 101 is manufactured for use in solid state Li-ion batteries. The active material can include, without limitation, cathode materials such as lithium transition metal oxides, lithium transition metal sulfides, lithium transition metal phosphates (e.g., lithium nickel-cobalt- manganese oxide (NMC), lithium iron phosphate (LFP), lithium cobalt oxide (LCO)), sodium manganese oxide, sodium cobalt phosphate, sodium nickel phosphate, sodium iron phosphate, sodium manganese phosphate, sodium iron hexacyanoferrate, sodium manganese hexacyanoferrate, or combinations thereof; and anode materials such as graphite, carbonaceous anode materials (e.g., graphite, graphene, disordered carbon, and the like), lithium transition metal oxides, Si-based composites, or combinations thereof. The binder can include, without limitation, a polymeric material, one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid (PAA), polyethylene oxide (PEO), poly(methyl methacrylate) (PM MA), carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polyurethanes, ethylene vinyl acetate (EVA), acrylic polymers, and polyethylene (PE). The conductive additive can include, without limitation, one or more of carbon black, carbon nanotubes, carbon fibers, graphene, or the like. The one or more solid state electrolytes can include, without limitation, solid polymer electrolyte PEO / LiTFSI, lithium lanthanum zirconium oxide (LLZO), lithium lanthanum titanate (LLTO), LisInCle, LiePSsCI, silica nanofillers, AI2O3 nanofillers, LLZO nanofillers, or combinations thereof. In some embodiments, the solid-state electrolyte can function as a binder, in which case the binder may be described as comprising a solid-state electrolyte. In some embodiments, the solid-state electrolyte can function as an active material, in which case the active material may be described as comprising a solid-state electrolyte.

[0048] In embodiments in which electrode 101 is manufactured for use in all-solid-state batteries, dry powder 135 includes an active material (same as described above for use in Li-ion batteries), a solid-state electrolyte (same as described above for use in Li-ion batteries), and an additive (each in a powder form). The additive can include, without limitation, a binder (same as described above for use in Li-ion batteries), a conductive additive (same as described above for use in Li-ion batteries), or combinations thereof.

[0049] Regardless of whether electrode 101 is manufactured for use in a Li-ion battery or all-solid-state battery, dry powder 135 comprises at least 70 wt% active material and less than 30 wt% other components. In addition, dry powder 135 preferably comprises a plurality of micro-particles at least partially coated in a plurality of nano-particles (i.e. , each micro-particle is at least partially coated in a plurality of nano-particles). As used herein, the term “micro-particle” refers to a single, individual particle, which may comprise, without limitation, a single crystal particle, a polycrystal particle, a partial crystalline particle, a composite particle, or an aggregate or agglomeration of a plurality of smaller particles (e.g., a plurality of smaller single crystal particles, a plurality of polycrystal particles, a particle of an amorphous material, a plurality of nano-particles, or combinations thereof), having a size (e.g., diameter or average diameter) greater than or equal to 1 .0 micron; and the term “nano-particle” refers to a single, individual particle, which may comprise, without limitation, a single crystal particle, a polycrystal particle, a particle of an amorphous material, or a partial crystalline particle having a size (e.g., diameter or average diameter) less than 1.0 micron. Thus, in embodiments described herein, the micro-particles in dry powder 135 have sizes that are preferably at least 10x the size of the nano-particles. For example, referring briefly to FIG. 3A, a single microparticle 190 comprising a first material (e.g., an active material), a first plurality of nanoparticles 191 comprising a second material (e.g., conductive additive), and a second plurality of nano-particles 192 comprising a third material (e.g., binder) are shown. The micro-particle 190 has a size that is at least 10x the size of the first plurality of nanoparticles 191 and the second plurality of nano-particles 192. In FIG. 3B, the microparticle 190 is shown coated in the nano-particles 191 and the nano-particles 192 to form one nano-particle coated micro-particle 193. A plurality of such nano-particle coated micro-particles 193 can be used as dry powder 135.

[0050] In general, the sizes of the various components in dry powder 135 (e.g., active material, binder, conductive additive, solid state electrolytes, etc.) can range from nanometers (e.g., nano-particles) to tens of microns (e.g., micro-particles). Forexample, the active materials may have sizes ranging from 0.5 micron to 40 microns, whereas the conductive additives and some of the solid polymer electrolyte (e.g., nanofillers) can have sizes less than 1 micron. In general, any one or more of the individual components in dry powder 135 (e.g., active material, binder, conductive additive, solid state electrolytes, etc.) can serve as and define the micro-particles, and any one or more of the individual components in dry powder 135 (e.g., active material, binder, conductive additive, solid state electrolytes, etc.) can serve as and define the nano-particles. For example, in FIGS. 3A and 3B, the micro-particle 190 may comprise an active material, the first plurality of nano- particles 191 may comprise conductive additives, and the second plurality of nano-particles 192 may comprise binder.

[0051] The surface area coverage of the nano-particles (e.g., nano-particles 191 , 192) on the outer surface of each micro-particle (e.g., micro-particle 190) is preferably larger than the critical surface area coverage value to ensure the micro-particles are separated by a minimum distance di93as shown in FIG. 3C. The typical value of critical surface area coverage value is 0.08% (i.e., 0.08% of the outer surface area of each microparticle is coated with the nano-particles).

[0052] Without being limited to this or any particular theory, the nano-particle coated micro-particles 193 in dry powder 135 advantageously exhibit reduced cohesiveness within dry powder 135, which enhances the flowability of dry powder 135 during spreading and compaction on substrate 105 to advantageously allow for the dry-cast, continuous and uniform formation of electrode 101 on substrate 105. In particular, it is believed that such nano-particle coated micro-particles (e.g., nano-particle coated micro-particles 193) exhibit shear thinning effects that enhance the flowability under increasing shear rates. In some embodiments, each micro-particle (e.g., each microparticle 190) preferably has a size ranging from 1.0 micron to 30.0 microns and each nano-particle preferably has a size ranging from 1.0 nm to 500.0 nm to advantageously enhance flowability of dry powder 135. In general, the nano-particle coated microparticles forming dry powder 135 can be prepared by any suitable means known in the art (e.g., intensive dry mixing) and then added to powder feeder 131 for controlled deposition on substrate 105.

[0053] In addition to the active material, the binder, the conductive additive, and other optional components described above (e.g., solid state electrolytes for solid state Li-ion batteries), the dry powder 135 can optionally include other types of nano-particles as functional additives to fine-tune particular aspects of battery performance such assafety, energy density, integrity, rate performance, and cycle life. For instance, TiC>2 nano-particles can be added in graphite (micro-particle) anode to improve rate capability and thermal stability. Further, particles or units of nanomaterials such as nanowires and / or nanotubes can be used in conjunction with nano-particles or as an alternative to nano-particles to coat the micro-particles to achieve similar effects. Examples of such other nanomaterials include hollow nano-particles, core-shell nano-particles, nano-dots, nano-tubes, nano-rods, nano-wires, nano-sheets, (graphene quantum dots, silicon nano-wires, carbon nano-tubes, silicon nano-tubes, nano-sized carbon fiber, mesoporous carbon, graphene, etc.). Any such particles or units of nanomaterials preferably have at least one dimension less than 1.0 micron, and more preferably at least one dimension less than 100 nm.

[0054] Referring again to FIGS. 1 and 2, pre-shaping roller 140 pre-shapes and spreads dry powder 135 on the upper surface of substrate 105. More specifically, pre-shaping roller 140 generally flattens and spreads the continuous pile of dry powder 135 deposited on substrate 105 to form pre-spread layer 136 having a substantially uniform thickness. Pre-shaping roller 140 is vertically positioned above substrate 105 and has a central axis 145 about which it may rotate and a radially outer cylindrical surface 142 extending axially between the ends of roller 140. Pre-shaping roller 140 is positioned such that (i) central axis 145 is oriented perpendicular to feed direction 106 in top view (i.e. , looking downward perpendicular to substrate 105) and (ii) outer surface 142 directly contacts dry powder 135 deposited on substrate 105 by powder delivery system 130. In general, pre-shaping roller 140 may rotate about axis 145 in a first direction (e.g., counterclockwise in FIG. 1), may rotate about axis 145 in a second direction that is opposite the first direction (e.g., clockwise in FIG. 1 ), or not rotate about axis 145.

[0055] As previously described, pre-shaping roller 140 is positioned to directly contact and spread dry powder 135 on substrate 105 to form pre-spread layer 136. In particular, pre-shaping roller 140 is positioned at a minimum distance from substrate 105 to define a gap Gp(FIG. 1 ) measured from the upper surface of substrate 105 to outer surface 142 of pre-shaping roller 140. Thus, pre-spread layer 136 of dry powder 135 formed by pre-shaping roller 140 has a substantially uniform thickness the same as or substantially the same as the gap Gp. In some embodiments described herein, the gap Gpbetween pre-shaping roller 140 and substrate 105 ranges from 0.0 microns to 5000.0 microns, and alternatively ranges from 300.0 microns to 1000.0 microns. Pre-shaping roller 140 preferably has an outer diameter ranging from 1.0 to 100.0 cm.

[0056] In embodiments described herein, outer cylindrical surface 142 of pre-shaping roller 140 that directly contacts dry powder 135 is preferably a low friction surface to reduce friction between pre-shaping roller 140 and dry powder 135. The low friction surface preferably exhibits an average surface roughness Ra less than 0.05 micron, and alternatively less than 0.02 micron. In general, the low friction surface can be defined by a surface treatment or a coating. Examples of surface treatments and coatings include, without limitation, a polished surface, a carbide coating, a ceramic coating, chrome-plating, a PTFE coating, and a graphite coating (or the entire roller 160 can be made of a graphite material). The material selected for the outer cylindrical surface 142 of pre-shaping roller 140 that directly contacts dry powder 135 is preferably selected to reduce and / or prevent electrostatic charging or attachment of dry powder 135. Examples of suitable materials include conductive materials such as steel or chrome, which are preferably grounded.

[0057] As previously described, pre-shaping roller 140 that contacts dry powder 135 preferably has a friction reducing outer surface 142, and the upper surface of substrate 105 that directly contacts dry powder 135 preferably comprises a friction enhancing treatment 108. More specifically, the coefficient of friction (pSubstrate-Powder) between substrate 105 and dry powder 135 is preferably greater than the coefficient of friction (Mproiier-powder) between pre-shaping roller 140 and dry powder 135. The combination of these features advantageously offers the potential to ensure continuous dry-casting of dry powder 135.

[0058] Referring now to FIGS. 1 , 2, and 4, in this embodiment, patterning roller 150 is provided to divide the substantially uniform pre-spread layer 136 of powder 135 into a plurality of laterally adjacent, shaped lanes 137 of dry powder 135 on the upper surface of substrate 105. Voids or gaps 138 devoid or free of dry powder 135 are laterally positioned between lanes 137 of dry powder 135. Namely, one void 138 is laterally positioned between each pair of laterally adjacent lanes 137. As will be described in more detail below, the presence of voids 138 enhances the spreadability of dry powder 135 by spreading roller 160, thereby offering the potential for improved quality and uniformity of thickness of spread layer 139 of dry powder 135 formed by spreading roller 160.

[0059] Patterning roller 150 is vertically positioned above substrate 105 and has a central axis 155 about which it may rotate and a radially outer surface 152 extending axially between the ends of roller 150. Patterning roller 150 is positioned such thatcentral axis 155 is oriented perpendicular to feed direction 106 in top view (i.e., looking downward perpendicular to substrate 105), and thus, extends laterally across substrate 105. In general, patterning roller 150 may rotate about axis 155 in a first direction (e.g., counterclockwise in FIG. 1), may rotate about axis 155 in a second direction that is opposite the first direction (e.g., clockwise in FIG. 1 ), or not rotate about axis 155.

[0060] As best shown in FIG. 4, outer surface 152 of patterning roller 150 includes a plurality of axially-spaced annular grooves or recesses 153 separated by a plurality of axially-spaced annular projections or peaks 154. In other words, recesses 153 and peaks 154 are arranged in an alternating manner moving axially along outer surface 152. Each annular peak 154 preferably extends to an outer radius R154 measured from central axis 155 to the radially outermost portion or point along the peak 154, and each recess 153 extends radially inward from the radially outermost portions or points along the axially adjacent peaks 154 to the same radial depth D153.

[0061] The cross-sectional geometries of recesses 153 and peaks 154 in a reference plane containing central axis 155 and oriented perpendicular to feed direction 106 generally define the geometry, shape, and spacing of lanes 137 of dry powder 135 and voids 138 positioned between lanes 137. Namely, as pre-spread layer 136 of dry powder 135 passes under patterning roller 150, annular peaks 154 generally urge portions of dry powder 135 into adjacent recesses 153. Consequently, dry powder 135 in recesses 153 generally takes the cross-sectional form and shape of recesses 153, and voids 138 devoid of dry powder 135 generally take the cross-sectional form and shape of peaks 154. For example, in this embodiment, each recess 153 has the same rectangular cross-sectional geometry and each peak 154 has the same rectangular cross-sectional geometry. Consequently, lanes 137 of dry powder 135 have rectangular cross-sectional geometries and voids 138 have rectangular cross-sectional geometries as shown in FIG. 5.

[0062] As previously described, patterning roller 150 is positioned to directly contact prespread layer 136 and convert pre-spread layer 136 of dry powder 135 into lanes 137 of dry powder 135 and voids 138 devoid of dry powder 135. In this embodiment, patterning roller 150 is positioned with central axis 155 radially spaced a uniform distance from substrate 105 equal to the radius R154, and thus, each peak 154 cuts or moves entirely through the entire thickness of pre-spread layer 136 (defined by gap Gp) and directly contacts substrate 105. As a result, discrete, laterally adjacent lanes 137 of dry powder 135 are formed and voids 138 extending to substrate 105 between lanes 137 are formedas shown in FIG. 5. As used herein, the term “discrete” is used to describe lanes 137 of dry powder 135 that are not connected or coupled by an underlying portion of prespread layer 136 as results from peaks 154 contacting substrate 105 and voids 138 extending to substrate 105. This is in contrast to lanes 137 of dry powder 135 and voids 138 devoid of dry powder 135 formed in an upper portion of pre-spread layer 136 such that lanes 137 are connected or coupled by the remaining, underlying portion of prespread layer 136 and voids 138 do not extend completely to substrate 105 as results from peaks 154 being spaced apart form substrate 105 but cutting or moving through a portion of the thickness of pre-spread layer 136 as is shown in FIGS. 6 and 7 described in more detail below.

[0063] Referring still to FIG. 5, in a reference plane oriented perpendicular to feed direction 106 (also oriented perpendicular to substrate 105), the cross-section of each lane 137 has a maximum width W137 measured laterally between the sides of the lane 137 and a maximum height H137 measured from the top of the lane 137 to the bottom of the lane 137. In addition, in the reference plane oriented perpendicular to feed direction 106, the cross-sections of each pair of laterally adjacent lanes 137 are laterally spaced apart a maximum distance D137 measured laterally between the adjacent sides of each pair of adjacent lanes 137. In the reference plane oriented perpendicular to feed direction 106, the cross-section of each void 138 has a maximum width W138 measured laterally between the adjacent sides of the pair of laterally adjacent lanes 137 (and equal to the maximum distance D137), and a maximum depth or height H138 measured from the tops of the laterally adjacent lanes 137 to the bottoms of the laterally adjacent lanes 137 (and equal to height H137). In addition, in the reference plane oriented perpendicular to feed direction 106, the cross-sections of each pair of laterally adjacent voids 138 are laterally spaced apart a maximum distance D138 measured laterally between the sides of the adjacent lane 137 disposed therebetween (and equal to the width W137). It should be appreciated that the maximum width W137 of each lane 137 (and the maximum distance D138 between laterally adjacent voids 138) is equal to the maximum distance between the axially adjacent peaks 154, the maximum height H137 of each lane 137 (and the maximum height H138 of each void 138) is equal to the radial depth D153 of the corresponding recess 153, and the maximum distance D137 (and the maximum width W138 of each void 138) is equal to the maximum distance between axially adjacent peaks 154. In embodiments described herein, the maximum width W137 of each lane 137 preferably ranges from 0.01 mm to 200.0 mm, the maximum height H137 of each lane137 preferably ranges from 0.02 mm to 3.0 mm, and the maximum distance D137 between lanes 137 is preferably greater than 0.0 mm and less than or equal to 200.0 mm. Accordingly, in embodiments described herein, the maximum distance D138 between each pair of laterally adjacent voids 138 preferably ranges from 0.01 mm to 200.0 mm, the maximum height H s of each void 138 preferably ranges from 0.02 mm to 3.0 mm, and the maximum width W138 of each void 138 is preferably greater than 0.0 mm and less than or equal to 200.0 mm.

[0064] In general, the dimensions of lanes 137 (e.g., the maximum height H137, the maximum width W137, and the maximum distance D137) and voids 138 (e.g., the maximum height H138, the maximum width W138, and the maximum distance D138) are chosen such that spread layer 139 of dry powder 135 covers the desired width of substrate 105 to a substantially uniform thickness (defined by a gap Gsdescribed below) following processing by spreading roller 160. More specifically, lanes 137 of dry powder 135 and voids 138 laterally adjacent lanes 137 having the preferred dimensions described above offer the potential to improve the consistency and quality (e.g., uniformity of thickness) of the spread of the dry powder 135 on substrate 105 by spreading roller 160 and the resulting electrode 101 formed by system 100. Although patterning roller 150 is shown and described as being downstream of pre-shaping roller 140 in the embodiment shown in FIGS. 1 and 2, in other embodiments, patterning roller 150 can be positioned upstream of pre-shaping roller 140 (i.e., between powder delivery system 130 and pre-shaping roller 140) and still offer the potential for similar benefits in terms of enhancing the consistency and quality of the spread of the dry powder 135 on substrate 105 by spreading rollers 160, 161 and the resulting electrode 101.

[0065] As previously described and shown in FIG. 4, peaks 154 of patterning roller 150 directly contact pre-spread layer 136 and convert pre-spread layer 136 of dry powder135 into discrete, laterally adjacent lanes 137 of dry powder 135 laterally spaced apart by voids 138 as shown in FIG. 5. However, in other embodiments, the peaks of the patterning roller (e.g., peaks 154 of patterning roller 150) may be spaced from the substrate (e.g., substrate 105) such that the peaks do not contact the substrate. In such embodiments, a portion of the pre-spread layer of dry powder (e.g., pre-spread layer136 of dry powder 135) remains below the laterally adjacent lanes (e.g., lanes 137) of dry powder and voids (e.g., voids 138), thereby connecting or coupling the laterally adjacent lanes of dry powder below the voids. In other words, the lanes and the voids are formed along an upper portion of the layer of dry powder. For example, FIG. 6illustrates patterning roller 150 positioned such that peaks 154 are radially spaced from substrate 105 (relative to axis 155) such that peaks 154 do not contact substrate 105. As a result and as shown in FIG. 7, a portion of pre-spread layer 136 of dry powder 135 remains below lanes 137 of dry powder 135 and voids 138. The portion of pre-spread Iayer136 below voids 138 connects or couples the laterally adjacent lanes 137 of dry powder 135. In other words, lanes 137 and voids 138 are formed along an upper portion of pre-spread layer 136 of dry powder 135. Each such lane 137 formed along the upper portion of pre-spread layer 136 of dry powder 135 preferably has a maximum width Wi37and a maximum height H137 as previously described, and further, the maximum distance D137 between such lanes 137 formed along the upper portion of pre-spread layer 136 of dry powder 135 is preferably as previously described. Likewise, each such void 138 formed along an upper portion of pre-spread layer 136 of dry powder 135 preferably a maximum height H138 and a maximum width W138 as previously described, and further, the maximum distance D138 between each pair of laterally adjacent voids 138 along the upper portion of pre-spread layer 136 of dry powder 135 is preferably as previously described.

[0066] Although a plurality of voids 138 are described and shown in FIGS. 4 and 5, in general, one or more voids (e.g., voids 138) can be formed and provided in the reference plane oriented perpendicular to the feed direction. In addition, as previously described and shown in FIGS. 4 and 5, recesses 153 and corresponding lanes 137, and peaks 154 and corresponding voids 138 have rectangular cross-sectional geometries in the reference plane oriented perpendicular to feed direction 106, and further, each recess 153 is the same, each peak 154 is the same, each lane 137 is the same, and each void 138 is the same. However, in other embodiments, the recesses (e.g., recesses 153), the peaks (e.g., peaks 154), the lanes (e.g., lanes 137), the voids (e.g., voids 138), or combinations thereof may have other cross-sectional geometries including, without limitation, semi-circular, triangular, trapezoidal, etc. In addition, one or more recesses may have may have cross-sectional geometries and / or sizes different from one or more other recesses, one or more peaks may have different cross-sectional geometries and / or sizes than one or more other peaks, one or more lanes may have different cross- sectional geometries and / or sizes than one or more other lanes, one or more voids may have different cross-sectional geometries and / or sizes than one or more other voids, or combinations thereof. Examples of alternative embodiments of patterning rollers 150’, 150”, 150”’ having recesses 153’, 153”, 153’”, respectively, peaks 154’, 154”, 154’”,respectively, resulting lanes 137’, 137”, 137”’, respectively, of dry powder 135, and resulting voids 138’, 138”, 138’”, respectively, having alternative cross-sectional geometries are shown in FIGS. 8, 9, 10.

[0067] As described above and shown in FIGS 1 and 2, patterning roller 150 is used to form laterally adjacent, shaped lanes 137 of dry powder 135 and voids 138 devoid of dry powder 138 laterally between lanes 137. However, in other embodiments, lanes of dry powder (e.g., lanes 137 of dry powder 135) and / or voids devoid of dry powder (e.g., voids 138) can be formed by other techniques such as via the powder delivery system, via vacuum or other powder removal technique, other mechanical techniques, or combinations thereof. For example, in some embodiments, the powder delivery system can be used to form lanes 137 and voids 138. In such embodiments, the function of the patterning roller (e.g., patterning roller 150) may be replaced by the powder delivery system, and thus, the patterning roller may be eliminated. Referring now to FIG. 11 , an alternative embodiment of a powder deliver system 130’ that can be used in system 100 in the place of powder delivery system 130 is shown. Powder delivery system 130’ includes a powder feeder 131’ and a powder de-lumping device 134 as previously described positioned below powder feeder 131’. Similar to powder feeder 131 previously described, powder feeder 131’ generally feeds or delivers dry powder 135 onto the upper surface of substrate 105, which carries and moves dry powder 135 in feed direction 106 through the remainder of the system. In general, powder feeder 131’ can be any suitable device for controllably feeding a dry powder such as a volumetric feeder (e.g., as screw feeder), a vibratory feeder, a gravimetric feeder (e.g., as loss-in- weight feeders), a hopper-based gravity feeder, or the like. In this embodiment, powder feeder 13T includes a hopper 132 as previously described and a plurality of laterallyspaced output nozzles 133’ extending downward from hopper 132. Hopper 132 generally holds a batch or load of dry powder 135, and output nozzles 133’ receive dry powder 135 held by hopper 132 and supplies dry powder 135 to substrate 105 at a desired feed rate (e.g., mass feed rate). The feed rate of dry powder 135 from each output nozzle 133’ is preferably the same. As output nozzles 133’ are laterally-spaced, dry powder 135 delivered by nozzles 133’ onto substrate 105 is deposited in a plurality of laterally adjacent lanes 137 with voids 138 positioned between each pair of laterally adjacent lanes 137. In this embodiment, nozzles 133’ are sufficiently laterally spaced such that lanes 137 are discrete. In general, the lateral spacing between laterally adjacent output nozzles 133’ and the number of output nozzles 133’ are chosen tocontrol the spacing between lanes 137 of dry powder 135 that are deposited on substrate 105, thereby defining the widths W s of voids 138.

[0068] Lanes 137 formed by nozzles 133’ and voids 138 therebetween preferably have the same geometric parameters as previously described (i.e., maximum width W137, maximum height H137, and maximum lateral spacing distance D137; and maximum height H138, maximum width W138 and maximum lateral spacing D138). In general, the maximum width W137 and maximum height H137 of each lane 137 (and hence maximum lateral spacing D138 between voids 138 and maximum height H138 of voids 138) can be controlled and adjusted by changing feed rate (e.g., mass feed rate) through each nozzle 133’ and the profile of the opening at the lower end of each nozzle 133’, and the maximum lateral spacing distance D137 (and hence maximum width W138 of voids 138) can be controlled and adjusted by changing the lateral spacing of the nozzles 133’. For most applications, outlet nozzles 133’ preferably have an outlet diameter ranging from 0.1 mm to 50.0 mm.

[0069] Referring again to FIG. 1 , spreading rollers 160, 161 uniformly spread lanes 137 of dry powder 135 (which may be discrete lanes 137 or lanes 137 disposed along the upper portion of pre-spread layer 136) on the upper surface of substrate 105 to form spread layer 139 of dry powder on substrate 105. Spreading rollers 160, 161 are vertically arranged one-above-the-other, and thus, may be described as an upper spreading roller 160 and a lower spreading roller 161. Each spreading roller 160, 161 has a central axis 165 about which it may rotate, a radially outer cylindrical surface 162, and an outer diameter Ds. In this embodiment, spreading rollers 160, 161 are positioned such that central axes 165 are disposed in a common vertical plane. Consequently, the uppermost portion of outer surface 162 of lower roller 161 is directly, vertically opposed to the lowermost potion of outer surface 162 of upper roller 160. The lower portion of upper roller 160 directly contacts and spreads dry powder 135 on substrate 105, while the upper portion of lower roller 161 directly contacts and supports the lower surface of substrate 105. In this embodiment, the upper portion of lower spreading roller 161 is positioned slightly above the upper portion of supply roller 110 such that substrate 105 slopes slightly upward as it moves from supply roller 110 to spreading rollers 160, 161 . More specifically, in some embodiments, substrate 105 slopes upward moving from supply roller 110 to spreading rollers 160, 161 at an angle greater than 0.0° and less than or equal to 45.0° relative to horizontal. In other embodiments, substrate 105 maynot slope upward moving from supply roller 110 to spreading rollers 160, 161 , but rather, may be horizontally oriented therebetween.

[0070] Outer diameter Dsof each spreading roller 160, 161 ranges from 5.0 mm to 500.0 mm. In this embodiment, the outer diameters Dsof spreading rollers 160, 161 are the same, however, in other embodiments, the outer diameters Dsof spreading rollers 160, 161 may be different.

[0071] In embodiments described herein, upper spreading roller 160 can rotate in a direction 166 about axis 165 (counterclockwise in FIG. 1), rotate in a direction 166’ about axis 165 that is opposite direction 166 (clockwise in FIG. 1), or not rotate about axis 165. In addition, in embodiments described herein, lower spreading roller 161 rotates in direction 166 about its axis 165 (counterclockwise in FIG. 1 ). Lower spreading roller 161 rotates at a uniform rotational speed, and upper spreading roller 160 (if it rotates) also rotates at a uniform speed. In embodiments described herein, the rotational speed of lower spreading roller 161 (and upper spreading roller 160 if it rotates) preferably ranges from 0 to 600.0 RPM. In some embodiments, both spreading rollers 160, 161 have the same rotational speed, however, in other embodiments, the rotational speeds of spreading rollers 160, 161 can be different.

[0072] Spreading rollers 160, 161 are vertically-spaced apart a sufficient distance to provide a gap Gsmeasured vertically from the upper surface of substrate 105 to the lowermost portion of outer surface 162 of upper spreading roller 160. Thus, the vertical distance between spreading rollers 160, 161 is equal to the thickness Tws plus gap Gs. It should be appreciated that gap Gsdefines the vertical thickness to which dry powder 135 is spread on substrate 105 by spreading rollers 160, 161. In embodiments described herein, gap Gs, and hence the vertical thickness of dry powder 135 after passing between spreading rollers 160, 161 , ranges from 0 to 3,000 micron, and alternatively ranges from 20.0 micron to 500.0 micron. In embodiments described herein, the ratio of the gap Gp defined by pre-shaping roller 140 to the gap Gs defined by upper spreading roller 160 (i.e., gap Gp / gap Gs) preferably ranges from 1 .1 to 20.0.

[0073] In embodiments described herein, outer cylindrical surface 162 of spreading roller 160 that directly contacts dry powder 135 is preferably a low friction surface to reduce friction between spreading roller 160 and dry powder 135. The low friction surface preferably exhibits an average surface roughness Ra less than 0.05 micron, and alternatively less than 0.02 micron. In general, the low friction surface can be defined by a surface treatment or a coating. Examples of surface treatments andcoatings include, without limitation, a polished surface, a carbide coating, a ceramic coating, chrome-plating, a PTFE coating, and a graphite coating (or the entire roller 160 can be made of a graphite material). The material selected for the outer cylindrical surface 162 of spreading roller 160 that directly contacts dry powder 135 is preferably selected to reduce and / or prevent electrostatic charging or attachment of dry powder 135. Examples of suitable materials include conductive materials such as steel or chrome, which are preferably grounded.

[0074] As previously described, upper spreading roller 160 that contacts dry powder 135 preferably has a friction reducing outer surface 162, and the upper surface of substrate 105 that directly contacts dry powder 135 preferably comprises a friction enhancing treatment 108. More specifically, the coefficient of friction (Msubstrate-powder) between substrate 105 and dry powder 135 is preferably greater than the coefficient of friction (Msroiier-powder) between upper spreading roller 160 and dry powder 135. The combination of these features advantageously offers the potential to ensure continuous dry-casting of dry powder 135.

[0075] To achieve the desired uniformity in the thickness of dry powder 135 after passing between spreading rollers 160, 161 (i.e., uniformity in gap Gsalong both the length and the width of substrate 105), spreading rollers 160, 161 are preferably manufactured and oriented relative to each other with relatively tight tolerances. More specifically, each spreading roller 160, 161 preferably has a radial run-out error after manufacture and assembly less than or equal to 10.0 micron, and alternatively less than or equal to 3.0 micron, and alternatively less or equal to 1.0 micron; and spreading rollers 160, 161 are preferably oriented such rollers 160, 161 exhibit a roller parallelism less than or equal to 10.0 micron, and alternatively less than or equal to 5.0 micron, and alternatively less than or equal to 1 .0 micron. As used herein, the terms “radial run-out error” and “roller parallelism” have meanings as are known in the art. Specifically, the term “radial run-out error” refers to the variation in the outer radius (difference between the maximum and minimum radius) of a roller; and the term “roller parallelism” refers to the variation in the distance (difference between the maximum and minimum distances) between the central axes of roller oriented substantially parallel to each other. The term “roller parallelism” can also refer to the variation in the closest gap distance between two rollers that are oriented substantially parallel to each other.

[0076] In some embodiments, upper spreading roller 160 and / or lower spreading roller 161 are heated to a temperature up to 300° C. Without being limited by this or anyparticular theory, heating one or more of the spreading rollers (e.g., spreading rollers 160, 161 ) offers the potential to enhance the consistency and quality (e.g., uniformity of thickness) of the spread layer of the dry powder on substrate (e.g., spread layer 139).

[0077] As shown in FIG. 1 and described above, the pair of spreading rollers 160, 161 are positioned such that central axes 165 are disposed in a common vertical plane. However, in other embodiments, only an upper spreading roller 160 as previously described may be provided. For example, as shown in FIG. 12, in some embodiments, the pair of spreading rollers 160, 161 of system 100 can be replaced with an upper spreading roller 160 as previously described and a pair of lower idler rollers 163 that are staggered or offset relative to upper spreading roller 160. Each idler roller 163 has a central axis 165 about which it rotates in a direction 166 (counterclockwise in FIG. 12) in response to direct engagement with the lower surface of substrate 105 moving in feed direction 106 and a radially outer cylindrical surface 162. The upper portion of each idler roller 163 directly contacts and supports the lower surface of substrate 105. However, in this embodiment, the uppermost portion of outer surface 162 of idler rollers 163 are not directly, vertically opposed to the lowermost potion of outer surface 162 of upper roller 160. Rather, one idler roller 163 (on the right in FIG. 12) is positioned proximal but upstream of upper spreading roller 161 and the other idler roller 163 (on the left in FIG. 12) is positioned proximal but downstream of the upper spreading roller 161.

[0078] Referring again to FIG. 1 , compaction rollers 170, 171 uniformly compact the spread layer 139 of dry powder 135 (after it has passed through spreading rollers 160, 161 ) on the upper surface of substrate 105. Compaction rollers 170, 171 are vertically arranged one-above-the-other, and thus, may be described as an upper compaction roller 170 and a lower compaction roller 171. Each compaction roller 170, 171 has a central axis 175 about which it rotates in a rotational direction 176, a radially outer cylindrical surface 172, and an outer diameter Dc. Compaction rollers 170, 171 are positioned such that central axes 175 are disposed in a common vertical plane. However, in other embodiments, the central axes of the compaction rollers (e.g., central axes 175 of compaction rollers 170, 171) may not lie in a common vertical plane. Consequently, the uppermost portion of outer surface 172 of lower roller 171 is directly, vertically opposed the lowermost potion of outer surface 172 of upper roller 170. The lower portion of upper roller 170 directly contacts and compacts dry powder 135 on substrate 105, while the upper portion of lower roller 171 directly contacts and supportsthe lower surface of substrate 105. In embodiments described herein, compaction rollers 170, 171 can apply a compaction load of up to about 3.5 tons / cm to compress dry powder 135 (along a line contact between roller 170 and dry powder 135), and more preferably apply a compaction load ranging from 0.01 to 1.5 tons / cm to compress dry powder 135 (along a line contact between roller 170 and dry powder 135).

[0079] Outer diameter Dcof each compaction roller 170, 171 ranges from 100.0 mm to 500.0 mm. In this embodiment, the outer diameters Dcof compaction rollers 170, 171 are the same, however, in other embodiments, the outer diameters Dcof compaction rollers 170, 171 may be different. Each compaction roller 170, 171 rotates about its corresponding axis 175 at a uniform rotational speed. In embodiments described herein, the rotational speed of each compaction roller 170, 171 is preferably greater than 0 RPM and less than or equal to 200.0 RPM. In this embodiment, both compaction rollers 170, 171 have the same rotational speed, however, in other embodiments, the rotational speed of compaction rollers 170, 171 may be different.

[0080] Rotational directions 176 of compaction rollers 170, 171 are opposite to each other. For example, in FIG. 1 , rotational direction 176 of upper compaction roller 170 is clockwise, whereas rotational direction 176 of lower compaction roller 171 is counterclockwise. However, due to the positioning of compaction rollers 170, 171 above and below, respectively, substrate 105 and dry powder 135, rotational directions 176 are generally in the same direction as feed direction 106 proximal substrate 105 and dry powder 135. In particular, due to the rotational direction 176 of upper compaction roller 170, the lower portion of outer surface 172 of upper compaction roller 170 contacting dry powder 135 moves in the same direction as feed direction 106; and due to the rotational direction 176 of lower compaction roller 171 , the upper portion of outer surface 172 of lower compaction roller 171 contacting substrate 105 moves in the same direction as feed direction 106. For example, as shown in FIG. 1 , at the point of engagement of outer surface 172 of upper compaction roller 170 with dry powder 135, outer surface 172 of upper compaction roller 170 is generally moving to the left while feed direction 106 is also to the left; and at the point of engagement of outer surface 172 of lower compaction roller 171 with substrate 105, outer surface 172 of lower compaction roller 171 is generally moving to the left while feed direction 106 is also to the left.

[0081] Compaction rollers 170, 171 are vertically-spaced apart a sufficient distance to provide a gap Gcmeasured vertically from the upper surface of substrate 105 to the lowermost portion of outer surface 172 of upper compaction roller 170. Thus, the verticaldistance between compaction rollers 170, 171 is equal to the thickness T s plus gap Gc. It should be appreciated that gap Gcdefines the vertical thickness to which dry powder 135 is compacted on substrate 105 by compaction rollers 170, 171 to form electrode 101. Thus, gap Gcdefines the thickness of electrode 101. In embodiments described herein, gap Gc, and hence the vertical thickness of dry powder 135 after passing between compaction rollers 170, 171 and the thickness of electrode 101 , ranges from 0.0 to 3,000.0 micron, and alternatively ranges from 0.0 micron to 500.0 micron.

[0082] In some embodiments, upper compaction roller 170 and / or lower compaction roller 171 are heated to a temperature up to 300° C. Without being limited by this or any particular theory, heating one or more of the compaction rollers (e.g., compaction rollers 170, 171) offers the potential to enhance the consistency and quality (e.g., uniformity of thickness) of the compacted and compressed layer of the dry powder on substrate that forms the electrode (e.g., electrode 101 ). In some embodiments, the upper compaction roller and / or the lower compaction roller are heated up to the melting point of the binder in the dry powder (e.g., dry powder 135).

[0083] Referring still to FIG. 1 , supply roller 110, receiving roller 120, lower spreading roller 161 , and lower compaction roller 171 support substrate 105 (and the components disposed thereon such as dry powder 135 and electrode 101 ) via direct contact with substrate 105. In this embodiment, web-stabilizing devices 180 are also provided to support to substrate 105 (and the components disposed thereon such as dry powder 135). In general, each web-stabilizing device 180 can be any suitable device for supporting substrate 105 (and the components disposed thereon such as dry powder 135) including, without limitation, an idler roller, an air bearing, etc. It should be appreciated that an air bearing offers the potential to support substrate 105, as well as reduce vertical vibrations of substrate 105 to allow a more precise transport of substrate 105 (and the components thereon). For example, an air bearing can be configured to apply both a positive pressure air cushion (above ambient atmospheric pressure) and a negative pressure suction (below ambient atmospheric pressure) to substrate 105 to allow frictionless support of substrate 105 while simultaneously reducing vibrations of substrate 105 for relatively high speed production operations. In embodiments including air bearings for web-stabilizing device(s) 180, the air bearings preferably minimize vertical vibrations of the portions of substrate 105 horizontally positioned between rollers110, 120, 160, 161 , 170, 171 to less than 3.0 micron (measured vertically from the lowest point of substrate 105 to the highest point of substrate 105).

[0084] Referring now to FIG. 13, an embodiment of a method 200 for manufacturing electrode 101 on substrate 105 is shown. Method 200 is performed with system 100 previously described and shown in FIG. 1 , and thus, will be described with reference to system 100.

[0085] In this embodiment, method 200 begins in block 201 in which dry powder 135 is prepared. As described above, dry powder 135 comprises a plurality of nano-particle coated micro-particles (e.g., nano-particle coated micro-particles 193) and is “dry” (i.e., does not include any solvent and is not prepared using any solvent). Next, in block 202, powder feeder 131 is loaded with dry powder 135, and in block 203, substrate 105 is moved in feed direction 106 via rollers 110, 120. Moving now to block 204, dry powder 135 is deposited on substrate 105 via powder feeder 131. As previously described, dry powder 135 passes through de-lumping device 134 in route to substrate 105 to break up any clumps in dry powder 135 before it lands on substrate 105. Dry powder 135 may be deposited as a single lane or as multiple lanes on substrate 105. Substrate 105 (moving in feed direction 106) transports dry powder 135 through the remainder of system 100. In particular, substrate 105 transports dry powder 135 in feed direction 106 from powder feeder 131 and de-lumping device 134 to pre-shaping roller 140 to form pre-spread layer 136 in block 205, then to patterning roller 150 to form voids 138 and lanes 137 (discrete lanes 137 or lanes 137 disposed along the upper portion of prespread layer 136) in block 206, then to spreading rollers 160, 161 to form spread layer 139 in block 207, then from spreading rollers 160, 161 to compaction rollers 170, 171 to form electrode 101 in block 208, and then from compaction rollers 170, 171 to receiving roller 120. During the transport of dry powder 135 through system 100, substrate 105 is vertically supported by rollers 161 , 171 and web-stabilizing device 180. In addition, web-stabilizing device 180 may function to reduce vibration of substrate 105 as previously described (i.e., when one or more web-stabilizing device(s) is an air bearing or idler rollers).

[0086] Referring still to FIG. 13, substrate 105 transports dry powder 135 between spreading rollers 160, 161 , which spread dry powder 135 over substrate 105. Several features of system 100 are specifically designed and configured to ensure a relatively high quality, substantially uniform spreading of dry powder 135 to the desired thickness defined by gap Gs. Without being limited by this or any particular theory, such featuresgenerally facilitate or enable enhanced lateral movement of dry powder 135 (i.e., the ability and ease by which the particles of dry powder 135 can move laterally relative to each other, particularly during spreading in block 207). Such features include, without limitation, inclusion of friction enhancing treatment 108 on substrate 105 that contacts dry powder 135, use of pre-shaping roller 140 to perform an initial or pre-spread of dry powder 135, formation of voids 138 in pre-spread layer 136 of dry powder 135 (e.g., discrete lanes 137 or lanes 137 disposed along the upper portion of pre-spread layer 136 formed by patterning roller 150), inclusion of low friction outer surface 162 on upper spreading roller 160 that contacts dry powder 135, and use of high precision spreading rollers 160, 161 (manufactured and oriented relative to each other with relatively tight tolerances with respect to radial run-out error and roller parallelism) to ensure an even, uniform spreading of dry powder 135 to the desired thickness defined by gap Gs. As will be described in more detail below, the relative velocity Vreibetween upper spreading roller 160 and substrate 105 can also contribute to facilitation or enablement of enhanced lateral movement of dry powder 135.

[0087] It should be appreciated that the position and location of the lateral edges of friction enhancing treatment 108 of substrate 105 can be used to define the positions and of the lateral edges of electrode 101. In particular, electrode 101 will have a width equal to the width of friction enhancing treatment 108 as dry powder deposited on substrate 105 outside of friction enhancing treatment 108 will generally fall away following manufacturing. The uncoated areas of substrate 105 (i.e., the areas of substrate 105 on which electrode 101 is not formed) can be used for placement of tabs. The area or shape of the friction enhancing treatment 108 can be defined by coating or laser induced texturing or patterning.

[0088] In the embodiment of system 100 shown in FIG. 1 and described above, electrode 101 is formed on one side of substrate 105. However, in other embodiments, an electrode (e.g., electrode 101 ) can be formed on both sides of the substrate (e.g., substrate 105). For example, referring now to FIG. 14, an embodiment of a system 100’ for dry manufacturing electrodes for energy storage devices such as Li-ion batteries and all solid-state batteries is shown. System 100’ is substantially the same as system 100 previously described with the exception that system 100’ produces a continuous sheet or layer of electrode material 101 on both sides of a substrate 105’. Accordingly, features of system 100’ that are the same as system 100 are given the same reference numerals, and for purposes of clarity and conciseness will not be described in detail withthe understanding such common features are the same as previously described with respect to system 100. The electrode material 101 and substrate 105’ can be cut as desired to produce a plurality of individual electrodes for use in energy storage devices, and thus, for purposes of clarity and further explanation, each layer of electrode material 101 may also be referred to herein as an electrode 101.

[0089] Referring still to FIG. 5, in this embodiment, system 100’ includes a supply roller 110, a receiving roller 120 horizontally spaced from the supply roller 110, a powder delivery system 130, a pre-shaping roller 140, a patterning roller 150, a pair of spreading rollers 160, 161 , a pair of compaction rollers 170, 171 , and a plurality of web-stabilizing device 180, each as previously described. Supply roller 110 generally provides a continuous sheet of substrate 105’ on which electrodes 101 are formed with system 100’, and receiving roller 120 generally receives the continuous sheet of substrate 105’ and electrode(s) 101 formed thereon.

[0090] Substrate 105’ is similar to substrate 105 previously described. In particular, substrate 105’ comprises a conductive base 107 in the form of a sheet of conductive material and a friction enhancing treatment 108 applied to the upper surface of base 107. However, in this embodiment, a friction enhancing treatment 108 is also applied to the lower surface of base 107. To manufacture electrodes 101 on both sides of substrate 105’, substrate 105’ is passed through system 100’ twice. More specifically, substrate 105’ is passed through system 100’ a first time to form electrode 101 on the upper surface of substrate 105’, and then substrate 105 is flipped over and passed through system 100’ a second time to form electrode 101 on the upper surface of substrate 105’, which was the lower surface of substrate 105’ on the first pass through system 100’. The first pass of substrate 105’ through system 100’ to form electrode 101 on one side of substrate 105’ is the same as previously described. The second pass of substrate 105’ through system 100’ to form the electrode 101 on the opposite side of substrate 105’ is the same as previously described except that the vertical distance between lower spreading roller 161 and substrate 105’, the vertical distance between lower compaction roller 171 and substrate 105’, and the vertical distance between webstabilizing device 180 and substrate 105’ are increased by gap Gcto accommodate the previously formed electrode 101 vertically positioned between rollers 161 , 171 and substrate 105’ and vertically positioned between web-stabilizing device 180 and substrate 105’.

[0091] Referring now to FIG. 15, yet another embodiment of a system 100” for dry manufacturing electrodes for energy storage devices such as Li-ion batteries and all solid-state batteries is shown. System 100” is substantially the same as system 100 previously described with the exception that system 100’ produces a continuous sheet or layer of electrode material 101 on both sides of a substrate 105’. Instead of passing substrate 105’ through the system twice, system 100” as shown in FIG. 15 can be used to coat both side with substrate 105’ passing through system once.EXAMPLES

[0092] The subject matter having been generally described, the following examples are given as particular aspects of the disclosure and are included to demonstrate the practice and advantages thereof, as well as aspects and features of the presently disclosed subject matter. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventors to function well in the practice of the present subject matter, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific aspects which are disclosed and still obtain a like or similar result without departing from the scope of the instant disclosure. It is understood that the examples are given by way of illustration and are not intended to limit the specification of the claims to follow in any manner.EXAMPLE 1

[0093] As previously described, the nano-particle coated micro-particles in dry powder 135 and the preferred size of the micro-particles in dry powder 135 offer the potential to advantageously enhance flowability, and hence spreadability, of dry powder 135. It may also be desirable to maintain the shear rate of dry powder 135 in an optimal or preferred range to achieve relatively free and stable flow of dry powder 135 to facilitate the spreading of a uniform layer of dry powder 135 on substrate 105 (both laterally or transverse to feed direction 106 and along feed direction 106). In the preferred range for the shear rate, dry powder 135 may exhibit shear-thinning effects to facilitate transition of dry powder 135 from an undesirable “jamming” state to a desirable “unjamming” state, which offers the potential to benefit the formation of uniform layer of dry powder 135 during spreading. The shear rate can be specified based on a variety of factors including the traveling speed of substrate 105, the rotational speed anddirection of upper spreading roller 160, the relative speed between substrate 105 and upper spreading roller 160, the size of the nano-particle coated micro-particles in dry powder 135, the size of gap Gs, the thickness of dry powder 135 between pre-shaping roller 140 and upper spreading roller 160, pressure / stress applied to dry powder 135 by spreading rollers 160, 161 , and the compaction level of dry powder 135. The following mathematical relations are proposed to specify the parameters related to shear rate and the range of parameters optimal for formation of a uniform layer of dry powder 135. FIG. 16 schematically illustrates the parameters used in the operation of upper spreading roller 160 to specify the operation conditions for obtaining a desirably uniform layer of dry powder 135.

[0094] The substrate 105 and dry powder 135 travel in the feed direction 106 with a speed sub. The relative speed Vreibetween substrate 105 (and dry powder 135 disposed thereon) and upper spreading roller 160 proximal the substrate 105 (and dry powder 135 disposed thereon) can be defined by equation 1 below:Vrel = Vsub + cuDs / 2 (Eq. 1 ) wherein VSUb is the speed of substrate 105, cu is the rotating angular velocity of upper spreading roller 160, and Ds is the diameter of the upper spreading roller. Note, upper spreading roller 160 can rotate in either direction or not rotate. The sign (+ or -) of co is defined such that co is positive when upper spreading roller 160 rotates in a rotational direction that is counter to the feed direction 106 of substrate 105 proximal the substrate 105 / dry powder 135, and co is negative when upper spreading roller 160 rotates in a rotational direction that is the same as the feed direction 106 of the substrate 105 proximal substrate 105 / dry powder 135.

[0095] It has been found the relative speed Vreihas a meaningful influence on the formation of a uniform spread layer 139 of dry powder 135 by upper spreading roller 160. In particular, experiments were conducted using a system similar to system 100 previously described and shown in FIG. 1 to produce electrodes 101 from dry powder 135 comprising NMC micro-particles having diameters of about 10 micron coated with carbon nano-particles and PVDF nano-particles. The composition was 96:2:2 wt% (NMC:PVDF:C). The uniformity of the thickness of spread layer 139 produced by the spreading rollers 160, 161 was measured and examined by a camera and a laser displacement sensor. In particular, the uniformity of the thickness of spread layer 139 was quantified by the peak to valley (P2V) variations (pm) across spread layer 139obtained at various relative speeds (Vrei) as shown in the graph of FIG. 17. Note that the relative speeds (Vrei) plotted in the graph shown in FIG. 17 were obtained based on Eq. 1 by varying VSUb and co values. In a relative speed (Vrei) range of 2.0 to 17.0 m / min, relatively low peak to valley variations were obtained. Whereas at a relative speed (Vrei) range greater than about 17.0 m / min, relatively high peak to valley variations were obtained. It should be appreciated that the smaller the peak to valley variations in spread layer 139, the more uniform the thickness of spread layer 139, and hence the more desirable and higher quality the spread layer 139 of dry powder 135. Accordingly, in embodiments described herein, for most operating parameters (e.g., substrate speed Vsub, sizes of gap Gs, sizes of gap Gp, rotational direction (+ or -) and speed (co) of the upper spreading roller, etc.) and compositions of dry powder 135, the relative speed Vreibetween the substrate (e.g., substrate 105) and the upper spreading roller (e.g., upper spreading roller 160) preferably ranges from 0.0 m / min to 100.0 m / min, alternatively ranges from 0.1 m / min to 50.0 m / min, and alternatively ranges from 2.0 m / min to 20.0 m / min.

[0096] Without being limited by this or any particular theory, it is further postulated that the characteristic shear rate experienced by dry powder 135 between substrate 105 and upper spreading roller 160 is important in producing a uniform spread layer 139 of dry powder 135 produced by spreading roller 160. The shear rate (y) experienced by dry powder 135 between substrate 105 and upper spreading roller 160 can be estimated by Eq. 2 as follows:wherein Vsub+ a>Ds / 2 is the relative speed (Vrei) defined above, and L is the characteristic length or distance over which shear occurs locally. The characteristic length L is related to size of gap Gs between upper spreading roller 160 and substrate 105 and the thickness of the localized shear band aD, where D is particle diameter (diameter of each nano-particle coated micro-particle) and a is in the range of 1-30. In order to produce a relatively smooth spread layer 139 with spreading roller 160 with low nonuniformity, in embodiments described herein, the shear rate y is preferably in the range 0.1 s-1to 8000 s'1for nano-particle coated micro-particles.

[0097] In addition to the foregoing analysis of the uniformity of spread layer 139 produced by spreading roller 160, a speed map was generated as shown in FIG. 18 to illustrate the influence of the relative speed (Vrei). To construct the graph shown in FIG. 18, web speed VSUb was varied from 2.0 to 14.0 m / min in 2.0 m / min increments. Roll speed (Dsco / 2) of upper spreading roller 160 was the speed at outer surface 162 converted from RPM. The roll speed was varied from -9.0 m / min to 13.0 m / min in 2.0 m / min increments. A negative roll speed means the spreading roller 160 rotates in a direction such that, at the point of contact with the powder 135, its surface velocity aligns with the feed direction 106 of substrate 105.

[0098] As shown in Figure 18, the small circles generally indicated the process parameters that produced relatively uniform powder layers 139 while the large circles generally indicated the process parameters that produced relatively poor uniformity powder layers 139. The uniformity of spread layer 139 was examined by a camera and a laser displacement sensor. In general, a uniform spread layer 139 was a continuous spread layer 139 with a P2V (peak to valley) variation less than 50% of the total thickness of spread layer 139, as measured by the laser displacement sensor. The speed map shown in FIG. 18 was specific to the configuration tested including the composition of the dry powder 135, powder loading, thickness of incoming pre-spread layer 136 (Gp), specifications of pre-shaping roller 140, specifications of spreading roller 160 (diameter, surface finishing, surface friction, etc), the spreading roller gap Gs, friction between substrate 105 and spreading roller 160, etc. Thus, it should be appreciated that any of these parameters can be modified to shift the process parameters that result in relatively good uniformity in spread layer 139.

[0099] The data shown in the graph of FIG. 18 indicate the following:■ A relative speed (VSUb + Dsco / 2) window that results in good uniformity of spread layer 139 is roughly 5.0 to 15.0 m / min in the tested configuration.■ The speed of spreading roller 160 (coDs / 2) is preferably controlled or adjusted to match the speed VSUb of substrate 105 so that relative speed (VSUb + Dsco / 2) is maintained within the desired range.■ At relatively high speeds VSUb of substrate 105, the spreading roll 106 is preferably rotated in the same direction as feed direction 106.EXAMPLE 2[ooioo] Studies of the spreading quality (uniformity) of dry powder 135 were conducted at relatively high speeds of substrate 105 to investigate the effect of the patterning roller 150. In the control study, dry powder 135 was deposited onto the substrate 105 and transported through a 750 pm gap Gpdefined by the pre-shaping roller 140. The thickness and lateral profile of the powder spread was characterized by a camera and a laser displacement sensor, as shown in FIG. 19A. The pre-spread layer 136 was then passed through a 100 pm gap Gs defined by the upper spreading roller 160 at a substrate 105 speed of 16.0 m / min and a counter-rotating spreading roller 160 speed of 4.7 m / min. The pre-spread layer 136 was not processed by a patterning roller 150. The image and longitudinal profile measurements of the resulting powder spread shown in FIG. 19B illustrated significant thickness inconsistencies, resulting in thickness variations exceeding the target thickness (gap Gs).

[0101] A patterning roller 150 was then positioned between the pre-shaping roller 140 and the spreading roller 160 to investigate its effect on the final powder spread quality (uniformity), which was inspected after the spreading roller 160 by a camera and a laser displacement sensor. The same amount of dry powder 135 was deposited onto the substrate 105 and transported through the pre-shaping roller 140 following the same parameters, and then the patterning roller 150, with a gap set to maintain a lateral average spread thickness close to 750 pm. As shown in FIG. 20A, the powder spread after the patterning roller 150 had a corrugated profile with an average thickness of around 750 pm. Following the patterning roller 150, the powder spread was passed 100 pm gap Gs defined by the upper spreading roller 160 at substrate 105 speed of 16.0 m / min and a counter-rotating spreading roller 160 speed of 4.7 m / min. A consistent 100 pm powder spread was achieved as shown in FIG. 20B.

[0102] In the manner described, embodiments of systems (e.g., systems 100, 100’) and methods (e.g., method 200) described herein can be used to dry manufacture electrodes for energy storage devices such as batteries (e.g., lithium ion batteries, solid state batteries, etc.). Such embodiments offer the potential for several advantages over conventional systems and methods. In particular, embodiments described herein can increase dry powder and electrode uniformity, and are applicable to a wide range of electrode compositions. In addition, the use of “dry” powder to form electrodes in accordance with embodiments described herein can reduce manufacturing costs, manufacturing equipment footprint, and energy consumption by eliminating the need for solvent drying and recovery.

[0103] While preferred embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teachings herein. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the systems, apparatus, and processes described herein are possible and are within the scope of the disclosure. For example, the relative dimensions of various parts, the materials from which the various parts are made, and other parameters can be varied. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims. Unless expressly stated otherwise, the steps in a method claim may be performed in any order. The recitation of identifiers such as (a), (b), (c) or (1 ), (2), (3) before steps in a method claim are not intended to and do not specify a particular order to the steps, but rather are used to simplify subsequent reference to such steps.

Claims

CLAIMSWhat is claimed is:1 . A system for dry manufacturing an electrode for an energy storage device, the system comprising: a substrate configured to move in a feed direction; a powder delivery system configured to deposit a dry powder onto a surface of the substrate, wherein the powder delivery system or a patterning roller is configured to form a plurality of laterally adjacent lanes of the dry powder on the surface of the substrate; an upper spreading roller positioned downstream of the powder delivery system relative to the feed direction, wherein the upper spreading roller has a central axis and a radially outer cylindrical surface, wherein the radially outer cylindrical surface of the upper spreading roller is configured to directly contact and spread the plurality of laterally adjacent lanes of the dry powder on the substrate to form a spread layer of the dry powder on the substrate; a pair of compaction rollers comprising an upper compaction roller and a lower compaction roller positioned below the upper compaction roller, wherein the upper compaction roller and the lower compaction roller are positioned downstream of the upper spreading roller relative to the feed direction, wherein each compaction roller has a central axis and a radially outer cylindrical surface, wherein the radially outer cylindrical surface of the upper compaction roller is configured to directly contact and compress the spread layer of the dry powder on the substrate to form the electrode on the surface of the substrate.

2. The system of claim 1 , wherein in a reference plane oriented perpendicular to the feed direction, each lane of the dry powder has a top, a bottom, and a pair of lateral sides extending from the top to the bottom; wherein each lane of the dry powder has a maximum height H measured from the top of the lane to the bottom of the lane in the reference plane and amaximum width W measured between the lateral sides of the lane in the reference plane; wherein each pair of laterally adjacent lanes of the dry powder is spaced apart a maximum distance D measured in the reference plane; wherein the maximum height H of each lane of the dry powder ranges from 0.02 mm to 3.0 mm, the maximum width W of each lane of the dry powder ranges from 0.01 mm to 200.00 mm, and the maximum distance D between each pair of laterally adjacent lanes of the dry powder is greater than 0.0 mm and less than or equal to 200.00 mm.

3. The system of claim 2, wherein the lanes of the dry powder are discrete or formed in an upper portion of the pre-spread layer of the dry powder.

4. The system of claim 1 , further comprising: a pre-shaping roller positioned between the upper spreading roller and the powder delivery system, wherein the pre-shaping roller is configured to flatten and spread the dry powder deposited on the substrate by the powder delivery system into a pre-spread layer on the substrate; the patterning roller positioned between the upper spreading roller and the preshaping roller, wherein the patterning roller has a central axis and a radially outer surface including a plurality of axially-spaced annular recesses and a plurality of axially-spaced annular peaks arranged in an alternating fashion, wherein the plurality of axially-spaced annular recesses and the plurality of axially-spaced annular peaks are configured to convert at least a portion of the pre-spread layer of the dry powder into the plurality of laterally adjacent lanes of the dry powder.

5. The system of claim 4, wherein the plurality of axially-spaced annular peaks of the patterning roller directly contact the surface of the substrate and the plurality of laterally adjacent lanes of the dry powder are discrete.

6. The system of claim 4, wherein the plurality of axially-spaced annular peaks of the patterning roller are spaced apart from the surface of the substrate and the pluralityof laterally adjacent lanes of the dry powder are formed in an upper portion of the prespread layer of the dry powder.

7. The system of claim 1 , wherein the powder delivery system comprises a powder feeder including a hopper and a plurality of laterally-spaced output nozzles extending from the hopper, wherein the plurality of laterally-spaced output nozzles are configured to deposit the dry powder on the surface of the substrate as the plurality of laterally adjacent lanes of the dry powder.

8. The system of claim 1 , wherein the powder delivery system comprises a powder feeder and a de-lumping device positioned between the powder feeder and the substrate.

9. The system of claim 1 , wherein the upper spreading roller is spaced above the surface of the substrate by a gap Gs and the upper compaction roller is spaced above the surface of the substrate by a gap Gc, wherein the gap Gc is less than the gap Gs, and wherein the gap Gs ranges from 20.0 micron to 500.0 micron and the gap Gc ranges from 0.0 micron to 500.0 micron.

10. The system of claim 1 , wherein the substrate comprises a conductive base and a friction enhancing treatment applied to the conductive base and defining the surface of the substrate, wherein the friction enhancing treatment is configured to increase a coefficient of friction pSubstrate-Powder between the substrate and the dry powder.11 . The system of claim 10, wherein the radially outer cylindrical surface of the upper spreading roller comprises a friction reducing surface configured to decrease a coefficient of friction pSroiier-powder between the radially outer cylindrical surface of the upper spreading roller and the dry powder, wherein the coefficient of friction pSroiier-powder between the radially outer cylindrical surface of the upper spreading roller and the dry powder is less than the coefficient of friction Psubstrate-powder between the friction enhancing treatment of the substrate and the dry powder.

12. The system of claim 1 , further comprising a lower spreading roller positioned downstream of the powder delivery system relative to the feed direction, wherein thelower spreading roller has a central axis and a radially outer cylindrical surface, wherein the lower spreading roller is positioned below the upper spreading roller and the substrate, and wherein the radially outer cylindrical surface of the lower spreading roller is configured to directly contact and support the substrate; wherein each spreading roller has a radial run-out error less than or equal to 3.0 micron; wherein the central axis of the upper spreading roller and the central axis of the lower spreading roller exhibit a roller parallelism less than or equal to 5.0 micron.

13. A method for dry manufacturing an electrode for an energy storage device, the method comprising:(a) depositing a dry powder onto a surface of a substrate moving in a feed direction;(b) transporting the dry powder on the substrate beneath a spreading roller to spread the dry powder into a spread layer of the dry powder on the substrate after (a), wherein a relative speed Vreibetween the substrate and the upper spreading roller at a point of contact of the upper spreading roller with the dry powder is greater than or equal to 0 m / min and less than or equal to 50.0 m / min; and(c) transporting the spread layer of the dry powder on the substrate beneath a compaction roller to compress the spread layer of the dry powder into the electrode on the surface of the substrate after (b).

14. The method of claim 13, wherein the relative speed Vreiis greater than or equal to 2.0 m / min and less than or equal to 20.0 m / min.

15. The method of claim 13, further comprising: forming a plurality of laterally adjacent lanes of the dry powder on the substrate during (a) and before (b) or after (a) and before (b); wherein (b) comprises spreading the lanes of the dry powder into the spread layer of the dry powder on the substrate.

16. The method of claim 15, wherein forming the plurality of laterally adjacent lanes of the dry powder comprises depositing the plurality of laterally adjacent lanes of the dry powder onto the surface of the substrate during (a) with a powder delivery system.

17. The method of claim 15, wherein forming the plurality of laterally adjacent lanes of the dry powder comprises transporting the dry powder on the substrate beneath a patterning roller after (a) and before (b), wherein the patterning roller has a central axis and a radially outer surface including a plurality of axially-spaced annular recesses and a plurality of axially-spaced annular peaks arranged in an alternating fashion.

18. The method of claim 13, wherein a shear rate applied to the dry powder during(b) ranges from range 0.1 s-1to 8000 s-1.

19. The method of claim 13, wherein the upper spreading roller has a first rotational speed ranging from 0 RPM to 600 RPM during (b) and the compaction roller has a second rotational speed greaterthan 0 RPM and less than or equal to 200.0 RPM during(c).

20. The method of claim 13, wherein the spread layer of the dry powder formed during (b) has a first thickness measured from the surface of the substrate to the upper spreading roller, wherein the electrode formed during (c) has a second thickness measured from the surface of the substrate to the compaction roller, wherein the first thickness is greater than the second thickness, wherein each thickness ranges from 20.0 micron to 500.0 micron.21 . The method of claim 13, wherein a coefficient of frictionsroiier-powder between the upper spreading roller and the dry powder is less than a coefficient of friction pSUbstrate- powder between the substrate and the dry powder during (b).

22. A system for dry manufacturing an electrode for an energy storage device, the system comprising: a substrate configured to move in a feed direction; a powder delivery system configured to deposit a dry powder onto a surface of the substrate;a spreading roller positioned downstream of the powder delivery system relative to the feed direction, wherein the spreading roller has a central axis and a radially outer cylindrical surface, wherein the radially outer cylindrical surface of the spreading roller is configured to directly contact and spread the dry powder on the substrate to form a spread layer of the dry powder on the substrate, wherein a coefficient of friction pSubstrate-Powder between the substrate and the dry powder is greater than a coefficient of friction Msroiier-powder between the spreading roller and the dry powder; a compaction roller positioned downstream of the spreading roller relative to the feed direction, wherein the compaction roller has a central axis and a radially outer cylindrical surface, wherein the radially outer cylindrical surface of the compaction roller is configured to directly contact and compress the spread layer of the dry powder on the substrate to form the electrode on the surface of the substrate.

23. The system of claim 22, further comprising: a pre-shaping roller positioned between the spreading roller and the powder delivery system, wherein the pre-shaping roller is configured to flatten and spread the dry powder deposited onto the surface of the substrate by the powder delivery system into a pre-spread layer of the dry powder on the surface of the substrate; a patterning roller positioned between the spreading roller and the pre-shaping roller, wherein the patterning roller is configured to (i) divide the prespread layer of the dry powder into a plurality of discrete laterally adjacent lanes of the dry powder or (ii) form a plurality of laterally adjacent lanes in an upper portion of the pre-spread layer of the dry powder.

24. The system of claim 23, wherein in a reference plane oriented perpendicular to the feed direction, each lane of the dry powder has a top, a bottom, and a pair of lateral sides extending from the top to the bottom; wherein each lane of the dry powder has a maximum height H measured from the top of the lane to the bottom of the lane in the reference plane and a maximum width W measured between the lateral sides of the lane in the reference plane;wherein each pair of laterally adjacent lanes of the dry powder is spaced apart a maximum distance D measured in the reference plane; wherein the maximum height H of each lane of the dry powder ranges from 0.02 mm to 3.0 mm, the maximum width W of each lane of the dry powder ranges from 0.01 mm to 200.00 mm, and the maximum distance D between each pair of laterally adjacent lanes of the dry powder is greater than 0.0 mm and less than or equal to 200.00 mm.

25. The system of claim 23, wherein the patterning roller has a central axis and a radially outer surface including a plurality of axially-spaced annular recesses and a plurality of axially-spaced annular peaks arranged in an alternating fashion.

26. The system of claim 25, wherein the plurality of axially-spaced annular peaks of the patterning roller directly contact the surface of the substrate such that the patterning roller is configured to divide the pre-spread layer of the dry powder into the plurality of discrete laterally adjacent lanes of the dry powder.

27. The system of claim 25, wherein the plurality of axially-spaced annular peaks of the patterning roller are spaced apart from the surface of the substrate such that the plurality of laterally adjacent lanes are formed in the upper portion of the pre-spread layer of the dry powder.

28. A method for dry manufacturing an electrode for an energy storage device, the method comprising:(a) depositing a dry powder onto a surface of a substrate moving in a feed direction;(b) forming at least one void in the dry powder on the surface of the substrate during or after (a), wherein each void is devoid of the dry powder;(c) contacting and spreading the dry powder on the surface of the substrate with a spreading roller after (b) to move at least some of the dry powder laterally into each void and form a spread layer of the dry powder on the surface of the substrate; and(d) compressing the spread layer of the dry powder into the electrode on the surface of the substrate after (c).

29. Th method of claim 28, wherein in a reference plane oriented perpendicular to the feed direction each void has a maximum height H and a maximum width W, and each pair of laterally adjacent voids is spaced apart a maximum distance D; wherein the maximum height H of each void ranges from 0.02 mm to 3.0 mm, the maximum width W of each void is greater than 0.0 mm and less than or equal to 200.00 mm, and the maximum distance D between each pair of laterally adjacent voids ranges from 0.01 mm to 200.00 mm.

30. The method of claim 28, wherein a relative speed Vreibetween the substrate and the spreading roller at a point of contact of the spreading roller with the dry powder is greater than or equal to 0 m / min and less than or equal to 50.0 m / min.31 . The method of claim 28, further comprising:(e) contacting and pre-spreading the dry powder on the surface of the substrate with a pre-spread roller after (a) and before (b) to form a prespread layer of the dry powder on the surface of the substrate; and(f) forming a plurality of laterally adjacent lanes of the dry powder on the substrate after (e) and before (c), wherein one of the at least one voids is laterally positioned between each pair of laterally adjacent lanes of the dry powder.

32. The method of claim 28, wherein a shear rate applied to the dry powder during (c) ranges from range 0.1 s-1to 8000 s-1, and wherein a coefficient of friction pSroiier-powder between the spreading roller and the dry powder is less than a coefficient of friction Psubstrate-powder between the substrate and the dry powder during (c).

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