Dry electrode manufacturing system and method

Abstract

The system includes a first dry electrode material transport system configured to transport the dry electrode material, a first calender roll, a second calender roll, and a controller. The second calender roll is configured to form a first nip between the first calender roll and the second calender roll. The first nip is configured to receive the dry electrode material from the first dry electrode material transport system and form a dry electrode material from the dry electrode material. The controller is configured to control the rotational speed of the second calender roll to be greater than the rotational speed of the first calender roll.

Description

[Technical field]

[0001] The described technology relates generally to energy storage devices, and more particularly to a simplified system and method for manufacturing dry electrodes for energy storage devices. [Background technology]

[0002] The electrodes can be implemented in electrical energy storage cells, which are widely used to power electrical, electromechanical, electrochemical, and other useful devices. Such cells include batteries, such as primary chemical cells and secondary (rechargeable) cells, fuel cells, and various capacitors, including ultracapacitors. The electrodes can also be implemented in water purification systems. Summary of the Invention [Problem to be solved by the invention]

[0003] It is desirable to reduce the operating costs and improve the efficiency of electrode manufacturing. [Means for solving the problem]

[0004] For purposes of summarizing the described technology, certain objects and advantages of the described technology are described. Not all such objects and advantages may be realized in any particular embodiment. Thus, for example, one skilled in the art will recognize that in implementing or practicing the described technology, it may be possible to achieve or optimize one advantage or group of advantages taught herein, without necessarily achieving other objects or advantages taught or suggested herein.

[0005] One aspect of the invention is a system for manufacturing a dry electrode for an energy storage device. The system includes a first dry electrode material transport system for transporting a dry electrode material, a first calender roll, a second calender roll, and a controller. The second calender roll is configured to form a first nip between the first calender roll and the second calender roll. The first nip is configured to receive the dry electrode material from the first dry electrode material transport system and form a dry electrode film from the dry electrode material. The controller is configured to control a rotational speed of the second calender roll to be greater than a rotational speed of the first calender roll.

[0006] In another aspect, the dry electrode film is not self-supporting.

[0007] In another aspect, the system further includes a third calender roll, and is configured to form a second nip between the third calender roll and an upstream adjacent calender roll, and the second nip is configured to receive the dry electrode film from the first nip. In another aspect, the upstream adjacent calender roll is a second calender roll. In another aspect, the control unit is further configured to control a rotation speed of the third calender roll to be greater than a rotation speed of the second calender roll. In another aspect, the system includes a current collector source and supplies a current collector to the second nip, and the second nip is configured to receive the current collector and laminate it to the dry electrode film to form a dry electrode. In another aspect, the system includes a second dry electrode film and is configured to transport a second dry electrode material. In another aspect, the first nip is configured to receive a second dry electrode material from a second dry electrode material transport system and form a dry electrode from the first dry electrode material and the second dry electrode material. In another embodiment, the first dry electrode material and the second dry electrode material are the same material. In another embodiment, the system further includes a fourth calender roll, and is configured to form a third nip between the fourth calender roll and a calender roll adjacent to the downstream side of the fourth calender roll, and the third nip is configured to receive the second dry electrode material from the second dry electrode material delivery system and form a second dry electrode film. In another embodiment, the downstream adjacent calender roll is the third calender roll. In another embodiment, the control unit is configured to control the rotation speed of the third calender roll to be higher than the rotation speed of the fourth calender roll. In another embodiment, the system further includes a current collector supply source that supplies a current collector to the second nip, and the second nip is configured to receive a current collector and laminate the current collector to the first electrode film and the second dry electrode film to form a double-sided dry electrode.

[0008] One aspect of the invention is a laminator for producing an intermittent electrode, the laminator including a first calender roll, a second calender roll, one or more stack actuators, and one or more gap control actuators. The one or more stack actuators are configured to provide a first force between the first calender roll and the second calender roll during lamination of the intermittent electrode. The one or more gap control actuators are configured to provide a second force to the first and second calender rolls, the second force being opposite and counteracting the first force.

[0009] In another aspect, the laminator further includes a sensor and a controller, the sensor configured to sense an uncoated area of ​​the electrode film, and the controller configured to engage the one or more gap control actuators when the uncoated area of ​​the electrode film passes between the first and second calender rolls.

[0010] Another aspect of the invention includes a method of making a dry electrode for an energy storage device, the method including rotating a first calender roll at a first rotational speed, rotating a second calender roll at a second rotational speed, and delivering dry electrode material to a nip between the first and second calender rolls to form a dry electrode film, the second rotational speed being greater than the first rotational speed.

[0011] In some embodiments, the dry electrode material is in the form of free-flowing particles. In some embodiments, the dry electrode film, as formed, adheres to a second calendar roll.

[0012] Another aspect of the invention includes a method of making an intermittent electrode, the method including providing an intermittent electrode film and a current collector, transporting the intermittent electrode film and the current collector between a first calender roll and a second calender roll, applying a first force to the current collector between the first calender roll and the second calender roll, and applying a second force between the first and second calender rolls, the second force being opposite and counteracting the first force.

[0013] In some embodiments, a first force presses the intermittent electrode film against the current collector, and a second force provides a gap between the first and second rolls when laminating the uncoated areas of the intermittent electrode film. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a block diagram illustrating a manufacturing process for a dry electrode for an energy storage device. [Diagram 2] FIG. 2 shows an apparatus for forming a dry electrode film. [Figure 3A] FIG. 3A is a schematic side view of a multi-roll calender system. [Figure 3B] FIG. 3B shows the film formed by the calendar system. [Figure 4] FIG. 4 is an isometric view showing details of a multi-roll calender system. [Figure 5A] FIG. 5A illustrates the operational steps of the system shown in FIG. [Figure 5B] FIG. 5B illustrates the operational steps of the system shown in FIG. [Figure 5C] FIG. 5C illustrates the operational steps of the system shown in FIG. [Figure 6] FIG. 6 is a schematic side view of a combined calendar / laminator device for forming a dry electrode. [Figure 7] FIG. 7 is a schematic side view of an intermittently coated dry electrode according to one embodiment. [Figure 8A] FIG. 8A is a side view of the laminator arrangement. [Figure 8B] FIG. 8B is a front view of the laminator arrangement. [Figure 9] FIG. 9 shows a funnel-shaped filling hopper. [Figure 10] FIG. 10 shows the steps of calendering, including a scatter coat step, a continuous calender step, a calender step and a winding step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Energy storage devices such as lithium-ion batteries have been relied upon as the power source for many commercial and industrial applications, such as consumer devices, industrial devices, and battery-powered vehicles. However, the demands placed on energy storage devices are constantly and rapidly increasing. For example, the automotive industry is developing vehicles that rely on small, highly efficient energy storage, such as plug-in hybrid vehicles and pure electric vehicles. Lithium-ion batteries are well suited to meet future demands.

[0016] The key element of the storage capacity of an energy storage device is the electrode. The electrochemical properties of the electrode, such as the capacity and efficiency of a battery electrode, are governed by a variety of factors, including the dispersion of the active materials, binders, and additives; the physical properties of these materials, such as the particle size and surface area of ​​the active materials; the surface properties of the active materials; and the physical properties of the electrode film, such as density, porosity, cohesion, and adhesion. Dry processing systems and methods have traditionally used high shear and / or high pressure processing steps to grind and mix the electrode film materials. Such systems and methods may have contributed structural advantages over wet electrode films. However, the high processing pressures and large equipment (and resulting large footprint) used to form self-supporting electrode films and dry electrodes leave room for improvement.

[0017] The systems and methods provided herein can be implemented to fabricate dry electrode films and electrodes for a variety of energy storage devices. As provided herein, the energy storage device may be a capacitor, a lithium ion capacitor (LIC), an ultracapacitor, a battery such as a lithium ion battery, or a hybrid energy storage device that combines two or more of these aspects.

[0018] Various embodiments of the present systems and methods provide improvements to the manufacturing of dry electrode films and dry electrodes for energy storage devices. The disclosed embodiments can provide a simplified and cost-effective manufacturing procedure for energy storage devices.

[0019] The materials and methods provided herein can be implemented into a variety of electrodes for energy storage devices and / or water purification. As provided herein, the energy storage device can be a capacitor, a lithium ion capacitor (LIC), an ultracapacitor, a battery such as a lithium ion battery, or a hybrid energy storage device that combines two or more of these aspects. In some embodiments, the methods and apparatus for forming dry electrode films as described herein enable continuous, multi-striped, and intermittent form factor electrodes.

[0020] The subject method and apparatus for forming dry electrode films provide one or more of the following advantages: Some embodiments allow for the production of high precision, low tolerance films with tunable density in various formats, both thin and thick. Some embodiments allow for films that are ultracapacitors (UCAP), batteries, Lcap, fuel cell electrodes, water purification electrodes, or combinations of electrodes. Some embodiments allow for reduced factory floor space, material handling requirements, and operator manpower by combining calendaring, lamination, stripping, and slitting into one machine. Some embodiments allow for multi-layer functionalized webs by using one or more dry electrode material supply systems, such as powder transport hoppers. Some embodiments increase the variety of available formulations that can be used to produce films and electrodes, such as self-supporting dry electrode films and dry electrodes. For example, lithium metal powder, silicon / silicon oxide, anode and cathode active materials impregnated into porous conductive carbon, such as molten sulfur and activated carbon, solid electrolyte, or other air / moisture sensitive materials.

[0021] Additional features or advantages provided by embodiments herein include a continuous process from raw material (such as powder) to a laminated electrode without winding / unwinding one or more layers to form the electrode. The dry electrode film formed by this system / method is not required to be self-supporting (at least initially or throughout the process) because it is positioned and supported by calender rolls at least partially, if not all, of the process steps. For example, when dry electrode material and a current collector are laminated to form a dry electrode, the dry electrode film is supported by at least one calender roll throughout all steps in a multi-roll calendering system, including the lamination step.

[0022] The present multi-roll calendar embodiments can have additional attributes not found in conventional calendaring. The number of calendar nips can be from two (three rolls) to six (seven rolls) or more, but with lower process pressures and forces. Each roll can be individually motor- and gear-driven and individually addressable. Line loads in a multi-roll calendaring system can be significantly lower than in a conventional calendar, yet the system can be configured to achieve thinner dry films. The speed of the individual rolls can be controlled, and the gap between the individual calendar nips can be controlled. The temperature of the individual rolls can also be controlled. For example, in some embodiments, the final roll of a laminated multi-roll system can be controlled to aid in lamination of the dry electrode film onto the current collector. Web manipulation is simplified and easy, and idler rolls in the web path can be reduced or eliminated. In some embodiments, adjacent roll sets (either between paired calendar nips or between two adjacent nips) can rotate at different speeds. For example, each downstream roll set (e.g., calendar nip) can be configured to rotate faster than the previous one. In addition, individual rolls in a two-roll nip set can be configured to rotate differently than other rolls in the same two-roll nip set. These different speeds can impart shear forces in the film and / or provide forces that allow the film to better adhere to any given roll.

[0023] In some embodiments, gauges such as gamma gauges can be used to control / measure film thickness or characteristic mass versus film thickness. The rollers may be fixed in a specific position with playless bearings (orientated but captured bearings may be required). Conical bearings or other bearing designs can be used to mount the rolls without play if the desired tight film thickness tolerances can be achieved. The embodiments do not require the same diameter rolls for each nip or roll within a nip. The finish of the roll surface may be a coating (e.g. chrome or hard surface ceramic) or patterned as in the case of embossed rolls.

[0024] In some embodiments, two multi-roll calendars can be arranged end-to-end to laminate the dry electrode film directly to a metal foil (e.g., a current collector) without the need to first remove the film and transport it to another apparatus. Thus, the same apparatus can laminate electrode layers to a current collector on one or both sides to form a single or double-sided electrode.

[0025] In some embodiments, the laminated electrodes can be either continuous web or intermittent electrode designs. Peeling the non-laminated film from the laminated web can be used for both continuous web and intermittent electrode designs. In some embodiments, the current collectors used in the system can be pre-coated with adhesive. Alternatively, the adhesive can be fed to one side of the film through a separate powder hopper on a multi-roll calendar system. This allows for direct lamination to the foil without first pre-coating the material. A slitter can be added after the lamination process to cut the laminated web to the width of the final electrode and wind up individual electrode rolls. In some embodiments, the device can be designed to be self webbing. For example, a continuous belt can be used under the roll to rise during webbing and properly direct the web to the next roll nip.

[0026] FIG. 1 is a block diagram showing a process for manufacturing a dry electrode for an energy storage device. As used herein, the term "dry" refers to the absence of liquid phase solvents and additives in the electrode mixing and coating steps described herein, except for the final electrolyte impregnation step. The process shown in FIG. 1 begins with dry mixing 18, which creates a dry mix from dry active material 12, dry conductive particles 14, and dry binder particles 16. A further dry mix can be created by dry mixing 19 of dry conductive particles 21 and dry binder particles 23, which are fed to dry fiberizer 26 or 29. The dry mix is ​​fiberized in dry fiberizer 20, e.g., a jet mill (not shown). In dry fiberizer 20, the dry mix is ​​subjected to high shear forces and physically stretched to form a network of fine web-like fibers. In dry feed 22, the individual dry particle mixes formed in steps 19 and 20 are fed into respective containers (not shown) to form dry films. The dry film is then dry compressed and calendered by a roll mill or calender 24 to provide an embedded / intermixed dry film or a self-supporting electrode film (or free-standing electrochemically active film). The embedded / intermixed dry film is attached to a current collector (such as a metal foil) 28. A more detailed process for manufacturing the embedded / intermixed dry film, including the types of materials that form the dry film and the materials that form the current collector, is disclosed in U.S. Patent No. 7,352,558, which is incorporated herein by cross-reference in its entirety.

[0027] The self-supporting electrode films produced as described above may provide improved properties compared to typical electrode films produced using wet processes. For example, the dry electrode films provided herein may provide one or more of improved film strength, improved cohesion, improved adhesion, improved electrical performance, or reduced defect occurrence. Defects include holes, cracks, and surface pits in the electrode film. The electrical performance may be specific capacitance. The film strength may be tensile strength.

[0028] FIG. 2 shows an apparatus for forming an electrode structure. The apparatus of FIG. 2 includes three interconnected system parts 100, 200, and 300. In 100, dry particles are initially stored in individual containers and fed to a high pressure nip of a roll mill as free flowing dry particles. The separate streams of dry particles mix together and begin to lose freedom of movement as the dry particles are fed to the nip. The mixed and compressed dry self-supporting film exits component 100 and enters component 200. The compressed dry film needs to be self-supporting upon exiting 100 in order to proceed to component 200 without collapsing. To be self-supporting, the film exiting the roll of component 100 needs to be thicker than the actual thickness of the electrode film desired. Thus, in system part 200, the self-supporting film is fed through a tension control system to a calendering system (shown as three large vertical rolls). The system includes multiple nips that repeatedly reduce the thickness of the dry film to approach the desired thickness / density. The dry film exits section 200 and enters system section 300, which may include one or more idler rolls, additional nips, and / or take-up / storage rolls to further process the dry film into the final dry electrode film, which is wound at a winding station. The final wound electrode film is transported to other equipment where it is unwound and laminated to a current collector to form a dry electrode.

[0029] 3A and 3B, in turn, show schematic side views of a multi-roll calender system 310 and a film 320 produced by the calender system. The calender system includes one or more dry electrode material delivery systems, such as powder delivery hoppers. For illustrative purposes, the system includes two powder hoppers, shown as powder hopper #1 and powder hopper #2. The particle size, density, porosity, and / or material type, and / or other material properties may be the same in powder hopper #1 and powder hopper #2. The particle size, density, porosity, and / or material type, and / or other material properties may be different in powder hopper #1 and powder hopper #2.

[0030] The illustrated calendering apparatus includes six rolls 330, although more or fewer rolls may be provided. The downstream roll 330B along the web path may be configured to rotate faster than the preceding upstream roll 330A. The faster speed of the downstream roll creates shear forces in the film, while at the roll nip, the film adheres to the faster rotating roll. The further downstream roll can rotate faster than the previous one, and thus the film can remain adhered to all rolls throughout the entire web path of the calendering apparatus. This adhesion allows the film initially formed in FIG. 3A to be formed from dry material, but not necessarily self-supporting, since the film is adhered to and supported by all rolls along the web path. This adhesion and support reduces or completely eliminates the need for idler rolls between the nips, as described with reference to FIG. 2. Compared to other dry film apparatus, such as the apparatus shown in FIG. 2, the increased shear forces in the nip also reduce the pressure and force required to calender the film to the desired thickness. Thus, less complex and less forceful (and therefore smaller) equipment can be used than in the system of Figure 2. The temperature of each roll in the system of Figure 3A can also be individually controllable. Figure 3B shows a side view of a film 320 produced by a calendering system such as that shown in Figure 3A, where the particles in powder hopper #1 are different in size than the particles in powder hopper #2.

[0031] FIG. 4 shows a multi-roll calender system 400. The system has six rolls 430 and one powder hopper 440, but this is for illustrative purposes and may have more or less. Along the web path, each of the six rolls is configured to rotate faster than the previous roll for film deposition as described above. FIG. 4 shows individual motors 450 (e.g., servo motors) whose speeds, accelerations, timing, etc. can be individually controlled by a controller (not shown). The controller may be further configured to control other aspects of the system, such as the gap distance between the rolls, the temperature of each roll, and / or other system parameters. The controller may be similarly implemented in the other systems described herein.

[0032] Figures 5A-C show several operational steps of the multiple roll calender system 400 of Figure 4. In Figure 5A, powder 445 is loaded into the roll nip of one of the calender systems. In Figure 5B, the film 420 is transported between the rolls 430 without the need for an idler roll. In Figure 5C, a doctor blade 460 assists in peeling the film from the last roll. The edges of the film are trimmed and the film is then wound onto a core 470.

[0033] FIG. 6 shows a combined calendar / laminator system 600 that can produce two dry electrode films and laminate them to a current collector to form a double-sided electrode. In FIG. 6, there are two dry electrode material delivery systems shown as powder hoppers 602 and 603, and four rolls 604, 605, 606, and 607. A current collector 610 is provided from a current collector source 608. A first dry electrode film 620 may be formed by calendaring particles from the powder delivery hopper 602 through a nip formed between rolls 604 and 605. A second dry electrode film 621 may be formed by calendaring particles from the powder delivery hopper 603 through a nip formed between rolls 606 and 607. Both films 620 and 621 may be laminated to the opposing first and second sides of the current collector 601, respectively. Lamination may be performed by compressing (e.g., calendering) the films 620 and 621 and the current collector 610 between a third nip formed between rolls 605 and 606. In addition to lamination, this third nip may also provide additional calendering of the films 620 and 621 to adjust the film thickness. After lamination between rolls 605 and 606, the double-sided electrodes are collected for further processing, e.g., at a winding station 609. As shown in FIG. 6, the roll nips are sequentially positioned close to each other, providing continuous calendering and film thickness reduction, reducing or completely eliminating the need for idler or dancer rolls. Each of the rolls is controlled for speed, acceleration, velocity, etc., as described elsewhere herein. Each successive roll rotates faster than the previous roll, causing the film to follow the rolls to the end where it unwinds from the last roll and is wound onto a core at a rewind station 609.

[0034] The system of Figure 6 can also be implemented to produce single-sided electrodes, for example by removing roll 607 and hopper 603 and not using film 621. In addition, rolls 604 and 607 are part of a belt calender system as shown, where the belt provides a surface and support for applying the dry electrode material thereon. One or more belt systems (rollers such as 604 and 607) or beltless systems (rollers such as 605 and 606), or combinations thereof, can be implemented in any of the embodiments herein.

[0035] 7 illustrates an intermittently coated electrode according to one embodiment. The intermittent electrode comprises intermittent coated portions 702 with a gap X of coating therebetween, forming uncoated foil portions 704. At least one uncoated foil portion 704 can be used to electrically connect the electrode to other elements, such as an electrode tab.

[0036] 8A-B show side and front views of an embodiment of a laminator, which can be implemented in a system such as system 600 in FIG. The rolls in the laminator of Figures 8A-8B may be similar to rolls 605, 606 of Figure 6. The laminator may include one or more lamination actuators, such as pressure cylinder 804, which provides the primary force for laminating the electrode film with the current collector that is fed to the laminator to form the electrode. However, in laminating an intermittent electrode as shown in Figure 7, the rolls collide when compressing the uncoated (foil only) portion 704. To reduce the effect of this collision, the laminator may include one or more gap control actuators. For example, cylinder 802 may be configured to oppose the force of cylinder 804 to maintain a constant gap during lamination of the uncoated portion. The sensor (Figure 8A) may be configured to detect the uncoated and unlaminated areas. When an uncoated or unlaminated area is detected, gap control cylinder 802 engages to counter the lamination pressure of the primary cylinder. The gap is maintained and the rolls do not strike the uncoated areas, thereby not distorting or damaging the intermittently laminated web.

[0037] FIG. 9 shows a funnel-type filling hopper that can be implemented in the embodiments of the system and method described herein. The hopper can be fed with the bulk material by suction or a worm conveyor. Inside the filling hopper, the bulk material is uniformly distributed and the height is kept constant during the scattering process. The formation of cavities and decomposition in the material is avoided through a special mixer. A rotating metering roller is fixed at the bottom side of the filling hopper. The cell size of the metering roller is selected according to the particle size of the bulk material. The bulk material is held by the metering roller 2 and peeled off by a flexible doctor blade 3. The precisely metered bulk material is then transported to a vibrating brush device 4. After the brushing process, the bulk material is inspected and transported to the subsequent substrate line 5.

[0038] FIG. 10 shows a calendering process 1000 including a diffuse coating step, a continuous calendering step, a calendering step, and a winding step. The diffuse coating device can deposit a very thin layer of powder onto a belt, which produces a thin film when the thin layer is calendered through the nip of the calender roll. The powder is collected in the groves or bristles of a primary rotating drum, and then a secondary rotating brush removes the powder from the groves or bristles, where it is deposited onto the moving belt. Once the powder is compressed into a film in the first nip, the film moves through subsequent nips to achieve the desired thickness and / or density.

[0039] The energy storage devices provided herein can be in any desired configuration, such as planar, spirally wound, button, interdigitated, pouched, etc. The energy storage devices provided herein can be components of systems, such as power generation systems, uninterruptible power source systems (UPS), photovoltaic systems, energy recovery systems for use in industrial machinery and / or transportation, etc. The energy storage devices provided herein can be used to power various electronic devices and / or motor vehicles, such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and / or electric vehicles (EVs).

[0040] As used herein, the terms "battery" and "capacitor" are given their ordinary and accustomed meaning to those of ordinary skill in the art. The terms "battery" and "capacitor" are not mutually exclusive. Capacitors and batteries can refer to electrochemical cells operating alone or as components of a multi-cell system.

[0041] It is understood that features, materials, properties or groups described in connection with a particular aspect, embodiment or example are also applicable to any other aspect, embodiment or example described in this section or elsewhere in this specification, except where incompatible. All features disclosed in this specification (including the accompanying claims, abstract and drawings), and / or all steps of any method or process so disclosed, may be combined in any combination, except where at least some features and / or steps are mutually exclusive. Protection is not limited to the details of the preceding embodiments. Protection extends to any novel feature or any combination of features disclosed in this specification (including the accompanying claims, abstract and drawings), or any novel step or process, any combination thereof.

[0042] Moreover, certain features that are described in the context of separate implementations in this disclosure may also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation may also be implemented separately in multiple implementations or in any suitable subcombination. Moreover, even if features are described above as working in a particular combination, one or more features of a claimed combination may, in some cases, be excluded from the combination. And combinations may be claimed as subcombinations or variations of subcombinations.

[0043] Additionally, operations may be depicted in the figures and described in the specification in a particular order. However, it is not necessary that such operations be performed in the order shown, or in sequential order, or that all operations be performed, to achieve desirable results. The exemplary methods and processes may incorporate other operations not shown or described. For example, one or more operations may be performed before, after, simultaneously with, or between the described operations. Additionally, operations may be rearranged or reordered in other implementations. Those skilled in the art will appreciate that in some embodiments, the actual steps taken in the illustrated and / or disclosed processes may differ from those shown in the figures. In some embodiments, certain of the steps described above may be removed and others may be added. Additionally, features and attributes of certain embodiments disclosed above may be combined in different ways to form additional embodiments, all of which are within the scope of the present disclosure. Additionally, the separation of system components in the embodiments described above should not be understood as requiring such separation in any embodiment. It should be understood that the components of the systems described above may generally be integrated into a single product or packaged into multiple products. For example, any of the components of the energy storage systems described herein may be provided separately or may be integrated together (e.g., packaged together, mounted together) to form an energy storage system.

[0044] For purposes of this disclosure, certain aspects, advantages, and novel features are disclosed. Not all such advantages are necessarily achieved in any particular embodiment. Thus, for example, one skilled in the art will recognize that the disclosure can be made or performed in a manner that achieves one advantage or group of advantages as taught herein without necessarily achieving other advantages as taught herein.

[0045] Conditional language, such as "can," "could," or "might," is intended to convey that certain embodiments include certain features, elements, and / or steps, while other embodiments do not, unless specifically stated otherwise or understood in the context in which it is used. Thus, such conditional language is not intended to generally imply that features, elements, and / or steps are required in one or more particular embodiments, nor is it intended that one or more embodiments include logic that determines whether or not those features, elements, and / or steps are included or performed in a particular embodiment, with or without the need for user input or direction.

[0046] A conjunctive phrase such as the phrase "at least one of X, Y, and Z," unless specifically stated otherwise, is understood in the context in which it is generally used to convey that an item, term, etc. may be either X, Y, or Z. Thus, this conjunctive phrase is not intended to imply that a particular embodiment requires the presence of at least one X, at least one Y, and at least Z.

[0047] As used herein, terms of degree, such as "approximate," "about," "generally," and "effectively," are used to indicate that a value, amount, or characteristic is close to a stated value, amount, or characteristic that performs a desired function or achieves a desired result.

[0048] The scope of the present disclosure is not intended to be limited by the specific disclosure of embodiments in this section or elsewhere herein, and may be defined by the claims set forth in this section or elsewhere herein or set forth in the future. Claim language shall be construed broadly in the language used in the claims, and not limited to the examples described herein or during prosecution of this application, which examples shall be construed in a non-exclusive manner.

[0049] Although specific embodiments have been described, these embodiments are presented as examples only and are not intended to limit the scope of the disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions, and modifications of the systems and methods described herein can be made without departing from the spirit of the disclosure. The appended claims and their equivalents are intended to cover such forms or modifications as may be deemed to be within the scope and spirit of the disclosure. Accordingly, the scope of the present invention is defined solely by reference to the appended claims.

Claims

1. 1. A system for manufacturing a dry electrode for an energy storage device, comprising: a first dry electrode material delivery system configured to deliver a first dry electrode material; a second dry electrode material delivery system configured to deliver a second dry electrode material; A first calender roll; a second calender roll forming a first nip between the second calender roll and the adjacent first calender roll, the first nip receiving the first dry electrode material from the first dry electrode material delivery system and forming a first dry electrode film from the first dry electrode material; a third calender roll; a fourth calender roll forming a second nip between the fourth calender roll and the adjacent third calender roll, the second nip configured to receive the second dry electrode material from the second dry electrode material delivery system and form a second dry electrode film; A control unit configured to control the rotation speed of the second calender roll to be greater than the rotation speed of the first calender roll and to control the rotation speed of the third calender roll to be greater than the rotation speed of the second calender roll, a third nip is formed between the second calender roll and the third calender roll; a current collector supply source that supplies a current collector to the third nip, the third nip receiving the current collector and laminating the first dry electrode film and the second dry electrode film to the current collector to form a double-sided dry electrode.

2. 2. The system of claim 1, The system, wherein the first dry electrode film is not self-supporting.

3. In the system of claim 1 or 2, A system wherein the first and second dry electrode materials are the same material.

4. In the system of claim 1 or 2, The control unit is configured to control a rotational speed of the third calender roll to be greater than a rotational speed of the fourth calender roll.

5. 1. A method for manufacturing a dry electrode for use in an energy storage device, comprising: rotating a first calender roll at a first rotational speed; rotating a second calender roll at a second rotational speed; rotating a third calender roll at a third rotational speed; rotating a fourth calender roll at a fourth rotational speed; delivering a dry electrode material to a first nip between the first calender roll and the adjacent second calender roll to form a first dry electrode film; delivering a dry electrode material to a second nip between the third calender roll and the adjacent fourth calender roll to form a second dry electrode film; the second rotational speed is greater than the first rotational speed; the third rotational speed is greater than the second rotational speed; A method for manufacturing a dry electrode, comprising laminating the first dry electrode film and the second dry electrode film onto a current collector through a third nip formed between the second calendar roll and the third calendar roll to form a double-sided dry electrode.

6. 6. The method of claim 5, The method of making a dry electrode, wherein the dry electrode material is in the form of free-flowing particles.

7. The method of claim 5 or 6, The method of making a dry electrode, wherein the first dry electrode film, as formed, is adhered to the second calender roll.

8. In the system of claim 1 or 2, The system wherein the first calender roll is a belt calender roll.

9. In the system of claim 1 or 2, The first dry electrode material delivery system is configured to deliver the dry electrode material directly to the first nip.

10. The method of claim 5 or 6, The method wherein the current collector is pre-coated with an adhesive.

11. The method of claim 5 or 6, The method, wherein the double-sided dry electrode is an intermittently coated electrode.

12. The method of claim 5 or 6, At least one of the first dry electrode film and the second dry electrode film comprises dry fiberized binder particles.

13. The method of claim 5 or 6, at least one of the first dry electrode film and the second dry electrode film comprises a dry active material, dry conductive particles, and dry binder particles.

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