Apparatus and method for manufacturing dry electrode

Abstract

The invention provides an apparatus and a method for manufacturing a dry electrode. The method includes mixing a dry electrode active material, a conductive material, and a binder through a mixer, wherein mixing the dry electrode active material, the conductive material, and the binder includes controlling a gap between a blade configured to be rotatable in the mixer and a chamber wall of the mixer during mixing. Based on the stage of mixing, the gap is adjusted using specific gap values of a coating time for compounding the conductive material with the active material, a dispersion time for uniformly dispersing the binder, and a fiberizing time for forming a network between the components. The method may also include an optional truncation time. The device features a mixer with adjustable vanes and a chamber for controlling the clearance during the mixing process. The device also includes a motor, a shaft, and an electric cylinder for blade movement, providing precise control of the mixing conditions.

Description

Technical Field

[0001] This disclosure relates to the manufacture of dry electrodes for use in batteries. Background Technology

[0002] Recently, the application of rechargeable batteries has been expanding to various fields, from small electronic devices to large energy storage systems. In particular, research and development of rechargeable batteries are actively underway due to the rapid growth of the electric vehicle market.

[0003] Electrodes for secondary batteries are typically manufactured using a wet process. In the wet process, a slurry is prepared by dissolving the electrode active materials, binders, and conductive materials included in the electrode in a solvent. However, recently, the dry process, which can increase the energy density of the battery without using the solvents required in the wet process, has attracted considerable attention.

[0004] In the dry electrode process, a mixture is prepared by mixing electrode active materials, conductive materials, and binders in the absence of solvents, and a dry electrode film is formed by a film-forming process via pressing or calendering. The electrode can then be manufactured by bonding the formed dry electrode film to a current collector.

[0005] Compared to wet electrode manufacturing processes, dry electrode manufacturing processes reduce manufacturing time and costs because no solvents are used, and because the thickness of the dry electrode film can be controlled, a dry electrode film with high energy density can be obtained.

[0006] Since no solvent is used in dry electrodes, the process of mixing dry electrode raw materials plays a very important role in the manufacture of dry electrode films. Summary of the Invention

[0007] This disclosure aims to solve the aforementioned problems related to the prior art, and the purpose of this disclosure is to provide an apparatus and method for manufacturing dry electrodes that can overcome the difficulties of using a high-shear mixer when mixing dry electrode mixtures.

[0008] Another object of this disclosure is to provide an apparatus and method for manufacturing dry electrodes that can reduce processing time.

[0009] Another object of this disclosure is to provide an apparatus and method for manufacturing dry electrodes, comprising a mixer configured to achieve excellent composite of electrode active materials and conductive materials, as well as the fiberization of a binder.

[0010] The purpose of this disclosure is not limited to the purposes mentioned above, and other purposes not mentioned herein will be clearly understood by those skilled in the art to which this disclosure pertains from the following description.

[0011] In order to achieve the above-mentioned objectives of this disclosure and to perform the features and functions of this disclosure (described later), the features of this disclosure are as follows.

[0012] In one embodiment, this disclosure provides a method for manufacturing a dry electrode, the method comprising: mixing a dry electrode active material, a conductive material, and a binder via a mixer, wherein mixing the dry electrode active material, the conductive material, and the binder includes controlling the gap between blades configured to be rotatable in the mixer and the chamber wall of the mixer during mixing.

[0013] Controlling the clearance can include moving the blade radially inward or outward relative to the chamber wall. The clearance can be controlled based on a mixture of dry electrode active material, conductive material, and binder.

[0014] The step of mixing the dry electrode active material, the conductive material, and the binder further includes: operating the mixer at a predetermined coating time with a first value interval; operating the mixer at a predetermined dispersion time with a second value interval; and operating the mixer at a predetermined fiberization time with a third value interval. The second value may be greater than the first and third values.

[0015] The mixing of dry electrode active materials, conductive materials, and binders may also include a predetermined chopping time for operating the mixer with a fourth value of the gap.

[0016] The coating time can be the time required for the conductive material to be composited with the dry electrode active material, configured such that the conductive material is coated onto the dry electrode active material by mixing. The coating time can be determined based on the conductivity measured at each predetermined time during the mixing of the dry electrode active material, the conductive material, and the binder. The fiberization time can be the time required for the binder to fiberize and is predetermined by testing, configured such that the binder fiberizes in the composite conductive material and the dry electrode active material.

[0017] The fiberization time can be determined based on the conductivity measured at each predetermined time during the mixing of the binder with the composite dry electrode active material and conductive material.

[0018] The method may also include forming a film from a dry electrode mixture in which dry electrode active material, conductive material and binder are mixed.

[0019] In another embodiment, this disclosure provides an apparatus for manufacturing dry electrodes, the apparatus including a mixer comprising a housing and blades rotatably disposed within the housing and configured to change the gap formed with the housing.

[0020] The mixer may also include a driver configured to move the blades radially inward or outward relative to the housing. The mixer may also include a motor; and a shaft configured to rotate via the motor, wherein the blades are connected to the shaft.

[0021] The device may also include an electric cylinder mounted on the shaft and configured to move the blades in the radial direction of the shaft.

[0022] The device may also include a controller configured to control the operation of the electric cylinder.

[0023] The mixer may also include a chamber configured to rotatably within the housing, with the clearance being the distance between the chamber wall and the blades. The mixer may be configured to mix dry electrode active materials, conductive materials, and binders.

[0024] In another embodiment, a method for manufacturing a dry electrode is provided. The method includes mixing a dry electrode active material, a conductive material, and a binder in a mixer, controlling the gap between a rotatable blade and the chamber wall of the mixer during mixing, wherein the method further includes: operating the mixer at a first gap value for a predetermined coating time to composite the conductive material and the dry electrode active material; operating the mixer at a second gap value for a predetermined dispersion time to uniformly disperse the binder; and operating the mixer at a third gap value for a predetermined fiberization time to fiberize the binder and form a network between the composite conductive material and the dry electrode active material.

[0025] The second value of the interval during the dispersed time can be greater than the first and third values, and the first and third values ​​can be selected independently.

[0026] As discussed, the method and system appropriately include the use of a controller or processor.

[0027] Other aspects and preferred embodiments of this disclosure are discussed below.

[0028] The above and other features of this disclosure are discussed below. Attached Figure Description

[0029] The above and other features of this disclosure will now be described in detail with reference to certain exemplary embodiments of the invention illustrated in the accompanying drawings, in which the drawings are given by way of example only and therefore do not limit the disclosure, and wherein:

[0030] Figure 1 The process of manufacturing dry electrodes is illustrated schematically;

[0031] Figure 2 An exemplary mixer is shown;

[0032] Figure 3 It is along Figure 2 The cross-sectional view of the mixer taken by line A1-A1 shows the process of fiberization of the composite dry electrode active material and conductive material, as well as the binder in the mixer.

[0033] Figure 4 A mixer according to one embodiment of the present disclosure is shown;

[0034] Figure 5 It is along Figure 4 A cross-sectional view taken from line A2-A2;

[0035] Figure 6A , 6B Figures 6C and 6D illustrate variable blades of a mixer according to one embodiment of the present disclosure;

[0036] Figure 7 This is a flowchart illustrating the control of the blade clearance of a mixer according to one embodiment of the present disclosure;

[0037] Figure 8A It is a graph showing the change in average conductivity over time of a predetermined amount of an exemplary dry electrode mixture (conductive material and dry electrode active material);

[0038] Figure 8B It is a graph showing the change in average conductivity over time of a predetermined amount of an exemplary dry electrode mixture after the addition of a binder; and

[0039] Figure 9 This is a graph showing the flowability of a specific dry electrode mixture before and after truncation.

[0040] It should be understood that the accompanying drawings are not necessarily drawn to scale and present slightly simplified representations of various preferred features illustrating the basic principles of this disclosure. Specific design features of this disclosure (including, for example, specific dimensions, orientations, locations, and shapes) will be determined in part by the specific intended application and environment of use.

[0041] In the accompanying drawings, reference numerals throughout the drawings refer to the same or equivalent parts of this disclosure. Detailed Implementation

[0042] In one aspect, this disclosure relates to the manufacture of dry electrodes for batteries, specifically to a method and apparatus for producing dry electrodes by mixing dry electrode active materials, conductive materials, and binders in a mixer with controlled gap adjustment. In some aspects, the method may involve precise control of the gap between rotatable blades and the chamber walls of the mixer, thereby allowing different gap values ​​during various stages of the mixing process. These stages include a coating period in which the conductive material is composited with the active material, a dispersion period in which the binder is uniformly distributed, and a fibrosis period in which the binder and the mixed materials form a network. The method may also include optional cutoff periods to adjust binder properties. This technique can improve the uniformity and quality of the dry electrode, contributing to enhanced battery performance. In other aspects, the apparatus is equipped with adjustable blades, a rotatable chamber, and an electric cylinder system for precise gap control throughout the process, preferably ensuring optimal mixing conditions and facilitating the efficient production of high-quality dry electrodes.

[0043] The specific structural or functional descriptions set forth in the embodiments of this disclosure are merely illustrative examples to describe implementations based on the concepts of this disclosure, and implementations based on the concepts of this disclosure may be embodied in different forms. Furthermore, it should be understood that this disclosure should not be construed as limiting itself to the embodiments set forth herein, and the embodiments of this disclosure are provided only to fully disclose this disclosure and to cover any modifications, equivalents, or substitutions falling within the scope and technical range of this disclosure.

[0044] In the following description of the embodiments, terms such as “first” and “second” are used only to describe various elements, and these elements should not be construed as being limited by these terms. These terms are only used to distinguish one element from other elements. For example, without departing from the scope of this disclosure, a first element described below may be referred to as a second element, and similarly, a second element described below may be referred to as a first element.

[0045] When a component or layer is described as "connected to" or "coupled to" another component or layer, it may be directly connected to or coupled to that other component or layer, or there may be intermediate components or layers. Conversely, when a component or layer is described as "directly connected to" or "directly coupled to" another component or layer, there may be no intermediate components or layers. Other terms used to describe relationships between components should be interpreted in a similar manner, such as "between" and "directly between," "adjacent" and "directly adjacent," etc.

[0046] Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular form may also be intended to include the plural form unless the context clearly indicates otherwise.

[0047] It should be understood that the term "vehicle" or "of a vehicle" or other similar terms as used herein include motor vehicles in a broad sense, such as passenger cars, including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft (including various boats and vessels), aircraft, etc., and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As mentioned herein, a hybrid vehicle is a vehicle with two or more power sources, such as a gasoline-powered and electric vehicle.

[0048] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to also include the plural forms. These terms are intended only to distinguish one component from another, and these terms do not limit the nature, order, or sequence of the constituent components. It should also be understood that when the terms “comprising” and / or “including” are used in this specification, they define the presence of the described features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term “and / or” includes any one and all combinations of one or more of the associated listed items. Throughout this specification, unless explicitly stated otherwise, the word “comprising” and variations such as “including” or “containing” will be understood to imply inclusion of the described elements, but do not exclude any other elements. Furthermore, the terms “unit,” “uniter,” “unitor,” and “module” described in the specification refer to a unit for performing at least one function and operation, and can be implemented by hardware components or software components and combinations thereof.

[0049] Although the exemplary implementation is described as using multiple units to perform the exemplary process, it should be understood that the exemplary process can also be performed by one or more modules. Furthermore, it should be understood that the term controller / control unit refers to a hardware device that includes a memory and a processor and is specifically programmed to perform the processes described herein. The memory is configured to store modules, and the processor is specifically configured to execute said modules to perform one or more processes further described below.

[0050] Furthermore, the control logic of this disclosure may be embodied in a non-volatile computer-readable medium containing executable program instructions that can be executed by a processor, controller, or the like. Examples of computer-readable media include, but are not limited to, ROM, RAM, optical disc (CD)-ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage devices. The computer-readable medium may also be distributed across a network-coupled computer system, enabling it to be stored and executed in a distributed manner, for example, via a telematics server or a controller area network (CAN).

[0051] Unless otherwise specified or obvious from the context, the term “about” as used herein shall be understood to mean within the normal tolerances in the field, such as within 2 standard deviations of the mean. “About” can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. All numerical values ​​provided herein are modified by the term “about” unless the context otherwise clarifies.

[0052] This disclosure will be described in detail below with reference to the accompanying drawings.

[0053] Dry electrodes can be manufactured without solvents from a dry electrode mixture M and a current collector. The dry electrode mixture M can be a mixture comprising an electrode active material, a conductive material (or a conductive additive or agent), and a binder. Furthermore, the dry electrode mixture M may also include additives.

[0054] The dry electrode can be either a positive electrode (cathode) or a negative electrode (anode). In some embodiments, when manufacturing the positive electrode, the electrode active material may include a positive electrode active material. As a non-limiting example, the positive electrode active material may include LCO (LiCoO2), NCM (Li(Ni,Co,Mn)O2), NCA (Li(Ni,Co,Al)O2), LMO (LiMnO4), LFP (LiFePO4), or sulfur.

[0055] In some embodiments, when manufacturing the negative electrode, the electrode active material may include a negative electrode active material. For example, the negative electrode active material may include natural graphite, artificial graphite, mesophase carbon microspheres (MCMB), or silicon-based active materials.

[0056] Conductive materials can include carbon-based conductive materials. For example, conductive materials can include carbon black, acetylene black, carbon fibers, or carbon nanotubes.

[0057] The adhesive may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), or copolymers thereof.

[0058] As an additive, solid polymer electrolytes such as poly(ethylene oxide) (PEO) or oxide-based or sulfide-based solid electrolyte components can be used.

[0059] The dry electrode material may include 70 to 99.9 wt% of electrode active material, 0.1 wt% to 20 wt% of conductive material, and 0.1 wt% to 20 wt% of binder. Additives may be added at a ratio of 0 to 20 wt%.

[0060] like Figure 1 As shown, a dry electrode mixture M is fabricated into a dry electrode film F through a series of film-forming processes involving the application of heat and pressure. First, the dry electrode mixture M, comprising electrode active material, conductive material, and binder, is mixed in a mixer 10 at a predetermined rate for a predetermined time. As a non-limiting example, the dry electrode mixture M can be fabricated using a rotating high-shear mixer, a fluid mixer using air, or the like. The predetermined time and rate can be adjusted by changing the rotational speed and operating time of the mixer 10.

[0061] The dry electrode mixture M mixed in mixer 10 can be formed into a dry electrode film F by a film-forming device. Specifically, the dry electrode mixture M mixed in mixer 10 can be guided to feeder 12 or roller press 20. The dry electrode mixture M can be initially pressed into a dry electrode film F by upstream roller press 20. Upstream roller press 20 rotates while providing pressing force to form the dry electrode mixture M into dry electrode film F. The dry electrode film F initially formed from the dry electrode mixture M can be further pressed by downstream roller press 30, and the thickness of the dry electrode film F can be adjusted by pressing. Subsequently, the dry electrode film F is wound by winder 40. Then, the dry electrode film F can be bonded or laminated to a current collector to manufacture a dry electrode.

[0062] Here, dry electrode mixture M refers to a powder in which the electrode active material, conductive material, and binder are suitably mixed and dispersed by mixer 10, and which is in a film-forming state when pressurized by film-forming device, i.e., roller press 20. In this disclosure, a mixture in which the electrode active material, conductive material, and binder simply exist together is referred to as dry electrode raw material M1, in order to distinguish this mixture from dry electrode mixture M.

[0063] The dry electrode mixture M can be considered to be properly mixed and dispersed through the fiberization of the binder and the composite of the electrode active material and the conductive material. In other words, the composite of the electrode active material and the conductive material, along with the fiberization of the binder, plays an important role in fabricating a dry electrode in the form of a self-supporting film. The composite of the electrode active material and the conductive material can be interpreted as coating the conductive material onto the surface of the electrode active material. The coating of the electrode active material with the conductive material can be achieved by applying a high shear force by the mixer 10. The fiberization of the binder can be interpreted as the binder being stretched thinly and long by the high shear force from the mixer 10 to connect the composite electrode active material and the conductive material through a network. The fiberization of the binder can particularly allow the binder to be used as a structure, so that the fabricated dry electrode can become a self-supporting film.

[0064] The composite of electrode active materials and conductive materials can enable the conductive material to be uniformly dispersed and coated on the surface of the electrode active material, thereby forming electron transport channels between the electrode active material particles and improving electron mobility. Furthermore, the composite may also affect the characteristics of the collision energy between particles during binder fiberization.

[0065] In the manufacturing process of the dry electrode, the fiberization of the binder and the composite of the electrode active material and the conductive material can be carried out during the mixing process via mixer 10. In other words, by mixing the electrode active material and the conductive material, and by adding the binder to the composite particles to fiberize the binder, a network can be formed in the dry electrode mixture.

[0066] refer to Figure 2 The mixer 10 includes a housing 101 and one or more blades 103. The blades 103 may be rotatably disposed within the housing 101. For example, the blades 103 may be mounted on a shaft 105 that rotates about an axis C1, and the shaft 105 may be configured to be rotated by a motor 107. A chamber 101a within the housing 101 may be rotatable. Therefore, both the chamber 101a and the blades 103 are rotatable.

[0067] The mixer 10 can be a high-shear mixer 10. The high-shear mixer 10 can apply a shear force to the gap G between the blade 103 and the chamber 101a or housing 101. This can be particularly advantageous in the composite of electrode active materials and conductive materials, as well as in the fiberization of adhesives. For example, a larger force can be applied to the dry electrode raw material M1 in the gap G, and the mixing time can be shortened because there are many points where this larger force is applied.

[0068] like Figure 3As shown, the high-shear mixer 10 can apply shear force to the dry electrode raw material M1 fed into the mixer 10 to manufacture the dry electrode raw material M1 located in the gap G into dry electrode material M. This manufacturing method can be interpreted as mechanical fusion, which induces interparticle bonding through high compressive and shear forces. Specifically, as the blade 103 rotates in direction R1, the dry electrode raw material M1 aggregates into a narrow space and is compressed by the blade 103. Then, a high shear force is applied to the dry electrode raw material M1 introduced into the gap G, so that the dry electrode raw material M1 can be made into dry electrode material M, wherein the composite of electrode active material 2 and conductive material 4 and the fiberization of binder 6 are completed. In other words, through this process, as indicated by the arrow (M1→M), the dry electrode raw material M1 can be made into dry electrode material M by coating the conductive material on the surface of the electrode active material 2 of the dry electrode raw material M1 and crushing and fiberizing the binder 6.

[0069] However, in chamber 101a, where a large amount of adhesive 6 is distributed, the adhesive 6 will not be crushed when passing through gap G and may act as a strong resistance. In this case, the load factor of motor 107 may increase, making it difficult to operate mixer 10. At this time, since the clump particles of dry electrode raw material M1 in mixer 10 have filled gap G, mixer 10 cannot even be operated again at low speed after it has stopped, and dry electrode raw material M1 in mixer 10 should be discarded.

[0070] As one approach, the input amount of dry electrode raw material M1 should be reduced to less than the capacity of mixer 10. This may reduce batch productivity. Alternatively, blade 103 should rotate at a low speed to adequately disperse binder 6, and the dry electrode raw material M1 should be mixed while gradually increasing the rotational speed (i.e., RPM) of blade 103. This approach may require a very long processing time.

[0071] Therefore, this disclosure aims to provide a mixer and a dry electrode manufacturing technology including the mixer, which can efficiently produce a dry electrode mixture M by changing the gap G according to the mixing conditions or mixing process.

[0072] like Figure 4 As shown, a mixer 200 according to one embodiment of the present disclosure includes a housing 202 and one or more blades 204. The blades 204 are disposed in the housing 202 and configured to be rotatable. The blades 204 can be mounted on a shaft 208 that rotates about an axis C1. The shaft 208 can be rotated about the axis C1 by a motor 210.

[0073] The housing 202 may include a rotatable chamber 202a within the housing 202. The chamber 202a may rotate together with the blades 204. For example, the chamber 202a is configured to rotate in the opposite direction to the blades 204. The blades 204 apply the required energy to the material within the mixer 200 by their rotation, and the applied energy may cause the material to undergo particle bonding, fiberization of the binder 6, etc.

[0074] As described above, the mixer 200 can be a high-shear mixer 200. The high-shear mixer 200 can apply a shear force to the gap G between the blade 204 and the chamber 202a. This mixer 200 can be particularly advantageous in the composite of the electrode active material 2 and the conductive material 4, and in the fiberization of the binder 6. For example, a larger force can be applied to the dry electrode raw material M1 in the gap G, and the mixing time can be shortened because there are many points where this larger force is applied.

[0075] The mixer 200 can apply shear force to the dry electrode raw material M1 to manufacture the dry electrode raw material M1 located in the gap G into a dry electrode mixture M. Specifically, by... Figure 3 As shown in the above process, the dry electrode raw material M1 placed in the mixer 200 can be made into a dry electrode material M in which the composite of electrode active material 2 and conductive material 4 and the fiberization of binder 6 have been completed.

[0076] The size of the gap G can be adjusted during the mixing process. In one embodiment, the blade 204 is configured such that the position of the blade 204 relative to the chamber 202a or the outer diameter of the blade 204 is variable. For this purpose, the blade 204 can be moved in the radial direction of the shaft 208. Additionally, refer to... Figure 5 The blade 204 can be moved by a drive (such as an electric cylinder 206 for moving the blade 204). In one example, the electric cylinder 206 can be mounted on a shaft 208, and the blade 204 can be connected to the electric cylinder 206. A control line 206a for the electric cylinder 206 can extend to the outside via the shaft 208.

[0077] The mixer 200 may also include a slip ring 212. The slip ring 212 can transmit signals through the fixed and rotating parts of the mixer 200 without twisting the control line 206a. The slip ring can be a contact type or a non-contact type.

[0078] The mixer 200 may also include a controller 214. The controller 214 can control the operation of the electric cylinder 206. Specifically, the controller 214 is configured to operate the electric cylinder 206 under predetermined conditions to adjust the diameter or gap G of the blades 204. The controller 214 may be a controller configured to control the operation of the mixer 200, or it may be a separate controller involved only in the operation of the electric cylinder 206.

[0079] The controller 214 is configured to adjust the gap G for each predetermined step of the mixing process. The mixing process for producing a dry electrode mixture M from dry electrode raw material M1 may include a coating step, a dispersion step, and a fiberization step. The coating step is a composite step in which a conductive material is coated onto the electrode active material during mixing via mixer 200 to composite with the electrode active material. In the dispersion step, the binder 6 is dispersed. In the dispersion step, the aggregated particles of the binder 6 can be uniformly dispersed therein. In the fiberization step, the binder 6 is fiberized. Through the fiberization of the binder 6, a network can be formed between the composite electrode active material 2 and conductive material 4 and the binder 6. In some embodiments, the mixing process may also include a truncation step. The truncation step can be selectively performed as a step of thinning or cutting the length of the binder 6 fiberized in the fiberization step.

[0080] refer to Figures 6A to 6D In each step of the mixing process, the gap G can be controlled by controller 214 to have values ​​within different ranges or different values, or values ​​within the same range or the same values. For example, in the coating step, the gap G can be set to a value within a first range; in the dispersion step, the gap G can be set to a value within a second range; and in the fiberization step, the gap G can be set to a value within a third range. Here, the first, second, and third ranges can be the same as or different from each other. In one instance, some of the first, second, and third ranges can be the same, and some can be different. In some embodiments, the gap G can be set to a value within a fourth range in the truncation step, and the fourth range can be the same as or different from the first, second, and third ranges.

[0081] In one implementation, it can be based on Figure 7 The flowchart shown controls the operation of mixer 200.

[0082] refer to Figure 7 The mixing process performed by mixer 200 begins in operation S700. In one embodiment, the mixing speed of mixer 200 can be kept the same in each step of the mixing process.

[0083] First, in operation S702, electrode active material 2 and conductive material 4 are placed into mixer 200.

[0084] Subsequently, in operation S704, controlling the gap G causes a coating step for the composite of electrode active material 2 and conductive material 4 to be performed (see...). Figure 6A The controller 214 can operate the electric cylinder 206 such that the clearance G has a value within a first range. In one test instance, the first range can be 2 to 12 millimeters (mm).

[0085] Each of the coating and fiberization steps in the mixing process can be performed for a predetermined time. The predetermined time can be determined by a pre-performed mixing process prior to mixing via mixer 200. For example, the predetermined time can be determined based on the average conductivity of the dry electrode mixture M. This is disclosed in Korean Patent Application No. 10-2023-0055862 filed by the applicant of this disclosure.

[0086] In short, during mixing via mixer 200, a predetermined amount of dry electrode mixture M is sampled at regular intervals (e.g., every 1 minute, 5 minutes, 10 minutes, etc.) to measure the conductivity of dry electrode mixture M. At each interval, conductivity is measured while a constant load (e.g., force or pressure) is applied to the dry electrode mixture M, and also at each load while increasing the load (e.g., increasing the load incrementally) (e.g., measuring conductivity at each force while successively applying forces of 1 (kilonewtons) kN, 2 kN, 3 kN, etc., and in this case, 20 force values ​​from 1 kN to 20 kN can be applied). For example, conductivity can be measured using a conductivity measuring device (e.g., a 4-point probe), and pressure can be uniformly applied to the dry electrode mixture M via a pressing device located above it. The average conductivity measured at each load within each time period is used as the average conductivity for that time period.

[0087] Figure 8A This is a graph showing the change in the average conductivity of a predetermined amount of dry electrode mixture over time. Figure 8A In the figure, the first time period is 5 minutes, the second time period is 10 minutes, the third time period is 20 minutes, the fourth time period is 30 minutes, the fifth time period is 40 minutes, and the sixth time period is 50 minutes. Each point in the figure represents the average conductivity within the corresponding time period. As shown, as the coating step proceeds (i.e., as time passes), the average conductivity increases with the improvement of the dispersion of the conductive material. However, after a certain time period (30 minutes in the example shown), the conductivity decreases. This decrease can be interpreted as a reduction in conductive channels due to structural degradation of the electrode active material or conductive material. Therefore, the time period with the highest average conductivity value can be determined as the execution time of the coating step in the mixing process.

[0088] Similarly, during the fiberization step, the average conductivity can be obtained for each time period. For example... Figure 8B As shown, after the adhesive is added to the mixing process, a predetermined amount of dry electrode mixture M is sampled at regular intervals (5 minutes, 10 minutes, 15 minutes, and 20 minutes in the illustrated example) to measure the conductivity of the dry electrode mixture M. During the fiberization step, gap control for fiberization can also be performed during a time period representing a time interval (15 minutes in the illustrated example) when the average conductivity is highest.

[0089] The execution time for the coating and fiberization steps can be determined by measuring the average conductivity. In the coating step, as mixing proceeds, the dispersion of the conductive material 4 improves, thus increasing the conductivity of the dry electrode mixture M. However, after a certain point, as the particles of the conductive material 4 are inserted between the particles of the electrode active material 2, the conduction channels decrease, thus reducing the conductivity of the dry electrode mixture M. Therefore, the most desired composite state can be obtained by using the time with the highest average conductivity. Thus, the coating step can be determined to be complete when the time determined by measuring the average conductivity has elapsed. This method can also be applied to the fiberization step.

[0090] Then, in operation S704, after the coating step is performed for a predetermined time with a gap within the first range, in operation S706, the adhesive 6 is placed into the mixer 200.

[0091] After the adhesive 6 is placed into the mixer 200, gap control for the dispersion step is performed in operation S708 (see [link]). Figure 6B In the dispersion step, the adhesive 6 can be uniformly dispersed or distributed within the mixer 200. The controller 214 can operate the electric cylinder 206 such that the gap G has a value within a second range. In one test example, the second range can be 16 to 60 mm. The reason why the gap G in the second range in the dispersion step is larger than the gap G in the first range in the coating step is to prevent the motor 210 from overloading the adhesive 6. The gap G in the coating step can be smaller than the gap G in the dispersion step, so that the composite of the electrode active material 2 and the conductive material 4 is carried out by high shear force, and the gap G in the dispersion step is larger than the gap G in the coating step, so that the adhesive 6 is uniformly dispersed.

[0092] In one implementation, the dispersion step can be performed multiple times by adjusting the gap G. For example, the mixer 200 can be operated with a gap G of 20 mm, and then the mixer 200 can be operated again with a gap G of 16 mm.

[0093] When the dispersion step is complete, the interval control of the fiberization step is performed in operation S710 (see...). Figure 6CIn the fiberization step, adhesive 6 can be fiberized. Controller 214 can operate electric cylinder 206 such that the gap G has a value within a third range. In one test example, the third range can be 2 to 12 mm. In the fiberization step, a smaller gap G is used than in the dispersion step. In the fiberization step, similar to the coating step, the gap G can be smaller than the gap G in the dispersion step, so that the fiberization of adhesive 6 is achieved by the mixer 200 through high shear force.

[0094] According to this disclosure, even if the load factor of motor 210 increases and the operation of motor 210 stops during the fiberization step of operation S708, the gap G can be increased, so that the dispersion step can be performed again without discarding the dry electrode raw material M1.

[0095] After the fiberization step is completed, gap control for truncation can be selectively performed in operation S712 (see [link]). Figure 6D Depending on the purpose of subsequent processes, a truncation step can be performed as needed to control fine fiberization. In the truncation step, a gap G smaller than the gap G in the fiberization step can be used to thin the adhesive 6 fiberized in the fiberization step or to cut the adhesive 6 to a shorter length. Therefore, a gap G with a value smaller than the third range can be used. The controller 214 can operate the electric cylinder 206 such that the gap G has a value within the fourth range.

[0096] The cutoff step can be performed selectively. In one instance, the cutoff step may be performed selectively primarily due to its relation to the pre-constructed dry electrode manufacturing facility. The dry electrode mixture M can typically be transported via vacuum through pipes. If a designated pipe is blocked by the dry electrode mixture M, a cutoff step can be selectively performed to improve the flowability of the dry electrode mixture M.

[0097] In one example, the execution time of the cutoff step can be determined by the length of the adhesive 6 based on the dry electrode mixture M, such as by electron microscopy. Images of the dry electrode mixture M are acquired by electron microscopy before and after the cutoff step, and the acquired images are compared to determine the required execution time of the cutoff step based on the degree of reduction in the length of the adhesive 6.

[0098] In another instance, the timing of the cutoff step can be determined by measuring the flowability of the dry electrode mixture M. The measurement of the flowability of the dry electrode mixture M is disclosed in Korean Patent Application No. 10-2023-0021097, filed by the applicant of this disclosure. In short, the flowability of the dry electrode mixture M can be evaluated based on ASTM D6128 of the American Society for Testing and Materials. Shear stresses within a specified range are applied to a certain amount of the dry electrode mixture M (e.g., via a mixer), and the internal forces are measured at equilibrium for each shear stress. At a certain point in time after the application of shear stress, powder collapse occurs within the dry electrode mixture M, and the stress at this point can be measured as the internal forces. The measured internal forces can be fitted to each applied shear stress, and the differential value at each shear stress can be defined as the flow index.

[0099] Figure 9 This is a graph showing the flowability of the dry electrode mixture before and after truncation. (See figure.) Figure 9 As shown, a difference appears in the flow graph when the length of the adhesive is shortened by a truncation step. This difference is due to the fact that as the length of the adhesive decreases, the amount of electrode material interfered with by the adhesive particles also decreases. Therefore, the execution time required for the truncation step can be determined by comparing the slope of the curve in the flow graph.

[0100] In some implementations, it can be assessed whether the cutoff step performed for the required execution time has been completed. For dry electrode mixture M in which the cutoff step has been performed for the required execution time, it can be assessed whether the dry electrode mixture M has obtained the desired state based on the Standard Test Method for Bulk Solids Characterization by Carr Indices (ASTM S5393) of the American Society for Testing and Materials. According to this standard test method, the stationary angle (°), fall angle (°), spatula angle (°), and loose bulk density (g / cm³) of the corresponding dry electrode mixture M can be measured. 3 Packed bulk density (g / cm³) 3 The measured values ​​also include compressibility (%), dispersibility (%), etc. Based on these measurements, it can also be determined whether the dry electrode mixture M in the desired state was obtained through the cut-off step.

[0101] When each step of the mixing process is completed, the dry electrode mixture M is discharged from the mixer 200 in operation S714. The discharged dry electrode mixture M is a well-composite and fibrous mixture and can be conveyed to the roller press 20 to manufacture dry electrodes (S716). Furthermore, the manufactured dry electrodes can be prepared into batteries.

[0102] According to this disclosure, a dry electrode manufacturing technique is provided that can overcome the difficulties of using a high-shear mixer when mixing dry electrode mixtures.

[0103] According to this disclosure, a dry electrode manufacturing technology that can reduce processing time can be provided.

[0104] According to this disclosure, a dry electrode manufacturing technology can be provided, which includes a fibrous mixer configured to achieve excellent composite of electrode active materials and conductive materials, as well as a binder.

[0105] As will be apparent from the above description, this disclosure provides an apparatus and method for manufacturing dry electrodes that overcomes the difficulties of using high-shear mixers when mixing dry electrode mixtures. This disclosure provides an apparatus and method for manufacturing dry electrodes that can reduce processing time.

[0106] This disclosure provides an apparatus and method for manufacturing dry electrodes, comprising a mixer configured to achieve excellent composite of electrode active materials and conductive materials, as well as the fiberization of a binder.

[0107] The effects of this disclosure are not limited to those described above, and those skilled in the art will clearly understand from the above description other effects not mentioned herein.

[0108] This disclosure has been described in detail with reference to preferred embodiments thereof. However, those skilled in the art will understand that changes may be made to these embodiments without departing from the principles and spirit of this disclosure, the scope of which is limited by the appended claims and their equivalents.

Claims

1. A method for manufacturing a dry electrode, comprising: The dry electrode active material, conductive material, and binder are mixed using a mixer. The mixing process includes controlling the gap between blades configured to rotatable in the mixer and the chamber wall of the mixer during mixing.

2. The method according to claim 1, wherein, Controlling the gap includes moving the blade radially inward or outward relative to the chamber wall.

3. The method according to claim 1, wherein, The gap is controlled based on the mixing progress of the dry electrode active material, the conductive material, and the adhesive.

4. The method according to claim 1, wherein, The mixture of the dry electrode active material, the conductive material, and the binder further includes: The mixer is operated with a first-value interval for a predetermined coating time; The mixer is operated with a second value of interval for a predetermined dispersion time; and The mixer is operated with a third value interval for a predetermined fiberization time.

5. The method according to claim 4, wherein, The second value is greater than the first value and the third value.

6. The method according to claim 5, wherein, The mixing of the dry electrode active material, the conductive material, and the binder also includes operating the mixer at a predetermined cutoff time with a fourth value of the gap.

7. The method according to claim 4, wherein, The coating time is the time required for the conductive material and the dry electrode active material to be combined, and is configured such that the conductive material is coated onto the dry electrode active material by mixing.

8. The method according to claim 7, wherein, The coating time is determined based on the conductivity measured at each predetermined time during the mixing of the dry electrode active material, the conductive material, and the adhesive.

9. The method according to claim 7, wherein, The fiberization time is the time required for the adhesive to fiberize and is predetermined by testing, configured to cause the adhesive to fiberize in the composite conductive material and dry electrode active material.

10. The method according to claim 9, wherein, The fiberization time is determined based on the conductivity measured at each predetermined time during the mixing of the adhesive with the composite dry electrode active material and conductive material.

11. The method according to claim 1, further comprising: A film is formed from a dry electrode mixture in which the dry electrode active material, the conductive material and the binder are mixed.

12. An apparatus for manufacturing dry electrodes, comprising a mixer, the mixer comprising: case; as well as One or more blades, the blades being rotatably disposed in the housing and configured to change the gap formed with the housing.

13. The apparatus according to claim 12, wherein, The mixer also includes a driver configured to move the blades radially inward or outward relative to the housing.

14. The apparatus according to claim 12, wherein, The mixer also includes: Electric motor; and A shaft, configured to rotate via the motor. The blade is connected to the shaft.

15. The apparatus of claim 14 further includes an electric cylinder mounted on the shaft and configured to move the blade in the radial direction of the shaft.

16. The apparatus of claim 15, further comprising a controller configured to control the operation of the electric cylinder.

17. The apparatus according to claim 12, wherein, The mixer also includes a chamber configured to rotatably within the housing, and the gap is the distance between the chamber wall and the blade.

18. The apparatus according to claim 12, wherein, The mixer is configured to mix dry electrode active materials, conductive materials, and binders.

19. A method for manufacturing a dry electrode, the method comprising: Dry electrode active materials, conductive materials, and binders are mixed in a mixer. Controlling the gap between the rotatable blades and the chamber wall of the mixer during mixing. The method further includes: The mixer is operated with a first-valued interval for a predetermined coating time to allow the conductive material and the dry electrode active material to combine. The mixer is operated at a second-value interval for a predetermined dispersion time to ensure uniform dispersion of the adhesive. The mixer is operated with a third-valued interval for a predetermined fiberization time to allow the adhesive to fiberize and form a network between the composite conductive material and the dry electrode active material.

20. The method according to claim 19, wherein, The second value during the interval of the dispersion time is greater than the first value and the third value, and the first value and the third value are selected independently.

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