Method and apparatus for manufacturing active material particles for dry electrode, and dry electrode film

Abstract

The invention relates to a method and an apparatus for manufacturing active material particles for a dry electrode, and a dry electrode film. The method of manufacturing an active material particle for a dry electrode includes: forming a film by rolling a first active material particle; forming a film powder by crushing the formed film; and obtaining second active material particles by screening at least a portion of the membrane powder. The average particle size of the second active material particles is larger than the average particle size of the first active material particles.

Description

Technical Field

[0001] Aspects of embodiments of the present disclosure relate to methods and apparatuses for manufacturing active material particles for dry electrodes. Background Art

[0002] Unlike primary batteries that are not designed to be (re)charged, secondary (or rechargeable) batteries are designed to discharge and recharge. Low-capacity secondary batteries are used in portable small electronic devices such as smartphones, feature phones, laptop computers, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources for driving engines in hybrid and electric vehicles and for storing electricity (e.g., home and / or utility-scale electricity storage). Secondary batteries generally include an electrode assembly composed of a positive electrode and a negative electrode, a case housing the same, and electrode terminals connected to the electrode assembly.

[0003] The positive and negative electrodes included in the electrode assembly can be manufactured based on the type of electrode. Electrodes can be classified into wet electrodes manufactured using a solvent and dry electrodes not manufactured using a solvent.

[0004] The above information disclosed in this background art section is for enhancing the understanding of the background of the present disclosure, and thus, it may contain information that does not constitute related (or prior) art. Summary of the Invention

[0005] Dry electrodes can be manufactured by forming a self-supporting film, which is manufactured in the form of a film and contains an active material, a binder, and a conductive material. However, during the process of forming the self-supporting film, the electrode film may lack flexibility, which can lead to film rupture or failure to wind the film onto a roller. In cases where the electrode cannot maintain its film form, it may be difficult to perform subsequent processes. Therefore, flexibility of the electrode film may be desirable.

[0006] Embodiments of the present disclosure may relate to methods and apparatuses for preparing active material particles for dry electrodes.

[0007] These and other aspects and features of the present disclosure will be described in or will become apparent from the following description of embodiments of the present disclosure.

[0008] According to one or more embodiments of the present disclosure, a method for manufacturing active material particles for a dry electrode includes: forming a film by rolling first active material particles; forming film powder by crushing the formed film; and obtaining second active material particles by sieving at least a portion of the film powder, wherein the second active material particles have an average particle size (particle diameter) greater than the average particle size of the first active material particles.

[0009] In an embodiment, the formation of the film may include: preparing a mixture including at least one of a conductive material or an adhesive and the first active material particles; and roll-pressing the mixture to form the film.

[0010] In an embodiment, the first active material particles may correspond to positive electrode active material particles or negative electrode active material particles.

[0011] In an embodiment, the first active material particles may include a lithium iron phosphate-based compound.

[0012] In an embodiment, the adhesive may include polytetrafluoroethylene (PTFE).

[0013] In an embodiment, the conductive material may include at least one of natural graphite, artificial graphite, or a silicon-based material.

[0014] In an embodiment, the average particle size of the first active material particles may be in the range of 0.1 μm to 3 μm.

[0015] In an embodiment, the grain size of each of the second active material particles may be larger than the grain size of each of the first active material particles.

[0016] In an embodiment, the average particle size of the second active material particles may be in the range of 4.5 μm to 30 μm.

[0017] In an embodiment, the method may further include forming a conductive material coating layer on the surface of each of the second active material particles by mixing the second active material particles with a conductive material.

[0018] In an embodiment, the thickness of the conductive material coating layer may be in the range of 1 nm to 500 nm.

[0019] In an embodiment, the formation of the film may include roll-pressing the first active material particles by a first roll and a second roll to form the film, and the rotation speed ratio of the first roll to the second roll may range from 1:1 to 1:20.

[0020] In an embodiment, the formation of the film may include roll-pressing the first active material particles at a temperature in the range of 25°C to 200°C to form the film.

[0021] In an embodiment, the formation of the film powder may include forming the film powder using at least one of a shear mill, a disk mill, a ball mill, a blade mill, or a hammer mill.

[0022] In an embodiment, the formation of the conductive material coating layer may include forming the conductive material coating layer by using a mixer.

[0023] In an embodiment, the formation of the conductive material coating layer may include forming the conductive material coating layer at a temperature in the range of 25°C to 150°C.

[0024] According to one or more embodiments of the present disclosure, an apparatus for manufacturing active material particles includes: a roller configured to roll a first active material particle to form a film; a crusher configured to crush the film to form film powder; and a sieve configured to screen at least a portion of the film powder to obtain second active material particles. The average particle size of the second active material particles is greater than the average particle size of the first active material particles.

[0025] In an embodiment, the apparatus may further include a mixer configured to form a coating layer of the second active material particles using a conductive material.

[0026] In an embodiment, a dry electrode film including the active material particles manufactured by the above method may be provided.

[0027] In an embodiment, the specific surface area of the dry electrode film may be in the range of 0.1 m 2 / g to 6 m 2 / g.

[0028] According to some embodiments of the present disclosure, the dry electrode film manufactured based on the coated second active material particles having a relatively large particle size may include (e.g., may contain) voids between the particles, such that they are relatively more flexible compared to a dry electrode film manufactured based on the first active material particles.

[0029] According to some embodiments of the present disclosure, granulation of the first active material particles may be promoted by using at least one of the conductive material or the binder. In addition, by adjusting the size of the through holes of the sieve, the second active material particles may be obtained in a state where the upper limit of the particle size is controlled (e.g., set). Thus, the size of the active material particles may be adjusted.

[0030] According to some embodiments of the present disclosure, the conductive material coating layer may protect the second active material particles from the influence of collision with other particles, thereby preventing or substantially preventing deformation or damage of the second active material particles.

[0031] According to some embodiments of the present disclosure, due to the presence of voids in the second film, the cohesive force between the coated second active material particles can be lower than the cohesive force between the first active material particles in the first film. Additionally, the second film can have a smaller specific surface area and a lower density compared to those of the first film because the coated second active material particles can be arranged (disposed) loosely in the second film. As a result, the second film can be relatively more flexible than the first film.

[0032] According to some embodiments of the present disclosure, the dry electrode film can be manufactured more smoothly (seamlessly) using the active material size control process according to one or more embodiments of the present disclosure described herein.

[0033] However, aspects and features of the present disclosure are not limited to those described above, and other aspects and features not mentioned will be clearly understood by those skilled in the art from the specific embodiments described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The following drawings attached to this specification illustrate embodiments of the present disclosure and further describe aspects and features of the present disclosure together with the specific embodiments of the present disclosure. Therefore, the present disclosure should not be construed as being limited to the drawings:

[0035] Figure 1 A diagram showing an example of active material particles according to an embodiment of the present disclosure;

[0036] Figure 2 A diagram showing a method of manufacturing second active material particles according to an embodiment of the present disclosure;

[0037] Figure 3 A diagram showing a method of obtaining coated second active material particles according to an embodiment of the present disclosure;

[0038] Figure 4 A diagram showing an example of a rolling process including a first rolling process and a second rolling process according to an embodiment of the present disclosure;

[0039] Figure 5 A schematic diagram showing an example of a film according to an embodiment of the present disclosure;

[0040] Figure 6 A photograph showing an example of a film according to an embodiment of the present disclosure;

[0041] Figure 7 A diagram showing characteristics of embodiments and comparative examples of a film according to one or more embodiments of the present disclosure;

[0042] Figure 8 A diagram showing an example of a dry electrode film manufacturing process according to an embodiment of the present disclosure; and

[0043] Figure 9 A flowchart showing an example of a method for manufacturing active material particles according to an embodiment of the present disclosure. Detailed Description

[0044] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Terms or words used in this specification and claims should not be construed as limited to their ordinary or dictionary meanings, but should be understood as meanings and concepts consistent with the technical concept of the present disclosure based on the principle that the inventor can appropriately define terms as his / her own lexicographer to best explain his / her invention.

[0045] The embodiments described in this specification and the configurations shown in the drawings are only some of the embodiments of the present disclosure, and do not represent all the technical concepts, aspects, and features of the present disclosure. Therefore, it should be understood that there may be various equivalents and modifications that can replace or modify the embodiments described herein at the time of filing this application.

[0046] It will be understood that when an element or layer is referred to as being "on", "connected to", or "coupled to" another element or layer, it can be directly on the other element or layer, directly connected or coupled to the other element or layer, or there can be one or more intermediate elements or layers. When an element is referred to as being "directly on", "directly connected to", or "directly coupled to" another element or layer, there are no intermediate elements or layers. For example, when a first element is described as being "coupled" or "connected" to a second element, the first element can be directly coupled or connected to the second element, or the first element can be indirectly coupled or connected to the second element via one or more intermediate elements.

[0047] In the drawings, for the sake of clarity, the dimensions of the various elements, layers, etc. may be exaggerated. The same reference numerals denote the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Additionally, when describing embodiments of the present disclosure, the use of "may" refers to "one or more embodiments of the present disclosure". When before or after a list of elements, recitations such as "at least one of..." and "any one of..." modify the entire list of elements and not individual elements of the list. When phrases such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from A, B, and C", or "at least one selected from among A, B, and C" are used to denote a list of elements A, B, and C, the phrase can refer to any and all suitable combinations or subsets of A, B, and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the term "use" may be considered synonymous with the term "utilize" respectively. As used herein, the terms "substantially", "about", and similar terms are used as approximate terms and not as terms of degree, and are intended to account for the inherent variations in measured or calculated values that would be recognized by a person of ordinary skill in the art.

[0048] It will be understood that although the terms "first", "second", "third", etc. may be used herein to describe various elements, components (constituents), regions, layers, and / or parts, these elements, components (constituents), regions, layers, and / or parts should not be limited by these terms. These terms are used to distinguish one element, component (constituent), region, layer, or part from another element, component (constituent), region, layer, or part. Thus, without departing from the teachings of the exemplary embodiments, the first element, component (constituent), region, layer, or part discussed below may be referred to as the second element, component (constituent), region, layer, or part.

[0049] For ease of description, spatial relative terms such as "beneath", "below", "lower", "above", "upper", etc. may be used herein to describe the relationship of one element or feature to another element or feature as shown in the figures. It will be understood that, in addition to the orientation depicted in the figures, the spatial relative terms are intended to encompass different orientations of the device during use or operation. For example, if the device in the figures is flipped over, an element described as "beneath" or "below" another element or feature will be positioned "above" or "on top of" the other element or feature. Thus, the term "beneath" can encompass both the orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein should be interpreted accordingly.

[0050] The terms used herein are for the purpose of describing embodiments of the present disclosure and are not intended to limit the present disclosure. As used herein, the singular forms "a", "an" are also intended to include the plural forms, unless the context clearly indicates otherwise. It will be further understood that when the terms "comprises" and / or "comprising" are used in this specification, they specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0051] In addition, any numerical range disclosed and / or recited herein is intended to include all sub-ranges of the same numerical precision contained within the recited range. For example, a range of "1.0 to 10.0" is intended to include all sub-ranges between the recited minimum value of 1.0 and the recited maximum value of 10.0 (and including the endpoints), i.e., having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Any maximum numerical limit recited herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit recited in this specification is intended to include all higher numerical limits contained therein. Thus, the applicant reserves the right to amend this specification (including the claims) to expressly recite any sub-ranges contained within the ranges expressly recited herein. All such ranges are intended to be inherently described in this specification.

[0052] Referring to two compared elements, features, etc. as "the same" may mean that they are "substantially the same". Thus, the phrase "substantially the same" may include cases having a deviation regarded as low in the art, such as a deviation of 5% or less. In addition, when a certain parameter is said to be uniform in a given region, it may mean that it is uniform on average.

[0053] Throughout the specification, unless otherwise stated, each element may be singular or plural.

[0054] Disposing any element "above (or below)" or "on (under)" another element may mean that any element may be disposed in contact with the upper (or lower) surface of the element, and another element may also be inserted between the element and any element disposed on (or under) the element.

[0055] In addition, it will be understood that when a component is referred to as being "coupled", "connected", or "joined" to another component, the elements may be directly "coupled", "connected", or "joined" to each other, or another component may be "inserted" between the components.

[0056] Throughout the specification, when stating "A and / or B", it means A, B, or both A and B, unless otherwise stated. That is, "and / or" includes any or all combinations of the recited items. When stating "C to D", it means C or greater and D or less, unless otherwise specified.

[0057] In this specification, the term "its combination" may refer to a mixture, stacked structure, composite, copolymer, alloy, blend, or reaction product of the described components (parts).

[0058] Unless otherwise defined herein, particle size may represent the average particle size. Particle size may also refer to the average particle size (D50), which is the diameter of the particles having a cumulative volume of 50% by volume in the particle size distribution. The measurement of the average particle size (D50) can be carried out by methods well known to those skilled in the art, for example, by a particle size analyzer or by examining images obtained by a transmission electron microscope or a scanning electron microscope. Another method involves using a measuring device utilizing dynamic light scattering to measure the particle size. By analyzing the data obtained by the measuring device utilizing dynamic light scattering and counting the number of particles in each particle size range, the value of the average particle size (D50) can be calculated. Alternatively, measurement can also be carried out by the laser diffraction method. Specifically, in the laser diffraction method, the particles of interest are dispersed in a dispersion medium and introduced into a commercially available laser diffraction particle size analyzer (e.g., Microtrac MT 3000). Ultrasonic waves of about 28 kHz with a power of 60 W are applied to the dispersion, and the average particle size (D50) corresponding to 50% of the particle size distribution in the analyzer can be calculated.

[0059] As used herein, the terms "positive electrode active material", "positive electrode", "negative electrode active material", and "negative electrode" can be understood as follows.

[0060] Positive electrode active material

[0061] The positive electrode active material may include a compound capable of intercalating and deintercalating lithium (lithiated intercalation compound). Specifically, at least one of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof can be used.

[0062] The composite oxide may be a lithium transition metal composite oxide. Specific examples of the composite oxide may include lithium nickel-based oxides, lithium cobalt-based oxides, lithium manganese-based oxides, lithium iron phosphate-based compounds, cobalt-free nickel manganese-based oxides, or combinations thereof.

[0063] As an example, the following compounds represented by any of the following chemical formulas can be used. Li a A 1-b X b O2-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, and 0 ≤ c ≤ 0.05); Li a Mn 2-b X b O 4-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, and 0 ≤ c ≤ 0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.5, and 0 < α < 2); Li a Ni 1-b- c Mn b X c O 2-α D α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.5, and 0 < α < 2); Li a Ni b Co c L1 d G e O2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, and 0 ≤ e ≤ 0.1); Li a NiG b O2(0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a CoG b O2(0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a Mn 1-b G b O2(0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a Mn2G b O4(0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a Mn 1-g G g PO4(0.90 ≤ a ≤ 1.8 and 0 ≤ g ≤ 0.5); Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2); or Li a FePO4(0.90 ≤ a ≤ 1.8).

[0064] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; and L1 is Mn, Al, or a combination thereof.

[0065] The positive electrode active material may be, for example, a high-nickel-based positive electrode active material having a nickel content of greater than or equal to about 80 mol%, greater than or equal to about 85 mol%, greater than or equal to about 90 mol%, greater than or equal to about 91 mol%, or greater than or equal to about 94 mol% and less than or equal to about 99 mol%, based on 100 mol% of the metals excluding lithium in the lithium transition metal composite oxide. The high-nickel-based positive electrode active material may be capable of achieving high capacity and may be applied to high-capacity, high-density rechargeable lithium batteries.

[0066] Positive electrode

[0067] The positive electrode for a rechargeable lithium battery may include a current collector and a positive electrode active material layer on the current collector. The positive electrode active material layer may include a positive electrode active material and may further include a binder and / or a conductive material (e.g., an electrically conductive material).

[0068] For example, the positive electrode may further include an additive that can act as a sacrificial positive electrode.

[0069] The amount of the positive electrode active material may be about 90 wt% to about 99.5 wt%, based on 100 wt% of the positive electrode active material layer. The amounts of the binder and the conductive material may be about 0.5 wt% to about 5 wt%, respectively, based on 100 wt% of the positive electrode active material layer.

[0070] The binder is used to well adhere the positive electrode active material particles to each other and to well adhere the positive electrode active material to the current collector. As non-limiting examples, examples of the binder may include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, a polymer including ethylene oxide (ethylene oxide), polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, nylon, etc.

[0071] The conductive material can be used to impart conductivity (e.g., electrical conductivity) to the electrode. Any material that does not cause chemical changes (e.g., does not cause undesirable chemical changes in a rechargeable lithium battery) and conducts electrons can be used in the battery. Examples of the conductive material can include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials containing copper, nickel, aluminum, silver, etc. in the form of metal powder or metal fiber; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0072] Al can be used as the current collector, but is not limited thereto.

[0073] Negative electrode active material

[0074] The negative electrode active material can include a material that reversibly intercalates / deintercalates lithium ions, lithium metal, a lithium metal alloy, a material capable of doping / dedoping lithium, or a transition metal oxide.

[0075] The material that reversibly intercalates / deintercalates lithium ions can include a carbon-based negative electrode active material, e.g., crystalline carbon, amorphous carbon, or a combination thereof. The crystalline carbon can be graphite such as unshaped, flaky, scaly, spherical, or fibrous natural graphite or artificial graphite. The amorphous carbon can be soft carbon, hard carbon, mesophase pitch carbonized product, calcined coke, etc.

[0076] The lithium metal alloy includes an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

[0077] The material capable of doping / dedoping lithium can be a Si-based negative electrode active material or a Sn-based negative electrode active material. The Si-based negative electrode active material can include silicon, a silicon-carbon composite, SiO x (0 < x < 2), a Si-Q alloy (where Q is selected from alkali metals, alkaline earth metals, group 13 elements, group 14 elements (excluding Si), group 15 elements, group 16 elements, transition metals, rare earth elements, and combinations thereof). The Sn-based negative electrode active material can include Sn, SnO2, a Sn-based alloy, or a combination thereof.

[0078] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to an embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, the silicon-carbon composite may include secondary particles (cores) that aggregate primary silicon particles, and an amorphous carbon coating layer (shells) on the surface of the secondary particles. The amorphous carbon may also be between the primary silicon particles, and for example, the primary silicon particles may be coated with the amorphous carbon. The secondary particles may be dispersed in an amorphous carbon matrix.

[0079] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core containing crystalline carbon and silicon particles and an amorphous carbon coating layer on the surface of the core.

[0080] The Si-based negative electrode active material or the Sn-based negative electrode active material may be used in combination with a carbon-based negative electrode active material.

[0081] Negative electrode

[0082] The negative electrode for a rechargeable lithium battery may include a current collector and a negative electrode active material layer on the current collector. The negative electrode active material layer may include a negative electrode active material and may further include a binder and / or a conductive material (e.g., an electrically conductive material).

[0083] For example, the negative electrode active material layer may include about 90 wt% to about 99 wt% of the negative electrode active material, about 0.5 wt% to about 5 wt% of the binder, and about 0 wt% to about 5 wt% of the conductive material.

[0084] The binder may be used to well adhere negative electrode active material particles to each other and to well adhere the negative electrode active material to the current collector. The binder may include a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof.

[0085] The non-aqueous binder may include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or a combination thereof.

[0086] The aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, epichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene-propylene-diene copolymer (ethylene propylene diene monomer rubber), polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0087] When using an aqueous binder as the negative electrode binder, a cellulose-based compound capable of imparting viscosity may be further included. The cellulose-based compound may include at least one of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may include Na, K, or Li.

[0088] The dry binder may be a fibrous polymer material. For example, the dry binder may be polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0089] The conductive material can be used to impart conductivity (e.g., electrical conductivity) to the electrode. Any material that does not cause a chemical change (e.g., does not cause an undesirable chemical change in a rechargeable lithium battery) and conducts electrons can be used in the battery. Non-limiting examples thereof may include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials in the form of metal powder or metal fiber including copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; or a mixture thereof.

[0090] The negative electrode current collector may include a copper foil, a nickel foil, a stainless steel foil, a titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, or a combination thereof.

[0091] Figure 1 A diagram showing an example of the active material particles according to an embodiment of the present disclosure.

[0092] The first active material particle 110 may be a positive electrode active material or a negative electrode active material. More specifically, the first active material particle 110 may be a lithium transition metal composite oxide, some examples of which include lithium nickel-based oxides, lithium cobalt-based oxides, lithium manganese-based oxides, lithium iron phosphate-based compounds, cobalt-free nickel manganese-based oxides, or a suitable combination thereof. For example, the first active material particle 110 may be a lithium iron phosphate-based compound. However, the present disclosure is not limited thereto, and the first active material particle 110 may correspond to a particle of an active material having a particle size that can be expected to increase.

[0093] The first active material particle 110 may be roll-pressed by a roller to form a film. Additionally, the formed film may be crushed using a crusher to produce film powder. Subsequently, by sieving at least a portion of the film powder using a sieve, the second active material particle 120 can be obtained.

[0094] The average particle size (D50) of the first active material particles 110 may be smaller than the average particle size (D50) of the second active material particles 120. For example, the average particle size (D50) of the first active material particles 110 may be 3 μm or less. The average particle size (D50) of the second active material particles 120 may range from 4.5 μm to 30 μm, which is greater than the average particle size (D50) of the first active material particles 110.

[0095] In an embodiment, the grain size of individual (single) second active material particles 120 may be greater than the grain size of individual first active material particles 110. As used herein, "grain" may refer to a solid having atoms arranged regularly to form a uniform or substantially uniform crystal structure and geometrically surrounded (e.g., around its periphery) by a geometric surface. During the process of forming a film by roll pressing the first active material particles 110, the arrangement of atoms within the first active material particles 110 may change, resulting in an increase in the grain size of individual second active material particles 120.

[0096] By using a mixer to mix the second active material particles and the conductive material with each other, coated second active material particles 130 including a conductive material coating layer 132 formed on the surface of the second active material particles 120 can be obtained. The conductive material coating layer 132 may help maintain or substantially maintain the morphology of the second active material particles 120. The method of forming the conductive material coating layer 132 will be described in more detail below with reference to Figure 3 More detailed description of the method of forming the conductive material coating layer 132.

[0097] Based on the coated second active material particles 130, a dry electrode film can be manufactured. The dry electrode film manufactured based on the coated second active material particles 130 having a relatively large particle size may include (e.g., may contain) voids between the particles, making them relatively more flexible compared to the dry electrode film manufactured based on the first active material particles 110. The process of manufacturing the dry electrode film will be described in more detail below with reference to Figure 8 More detailed description of the process of manufacturing the dry electrode film, and the further details regarding the dry electrode film prepared based on the second active material particles 120 will be described in more detail below with reference to Figures 4 to 7 More detailed description of the further details regarding the dry electrode film prepared based on the second active material particles 120.

[0098] Figure 2 A diagram showing a method of manufacturing second active material particles according to an embodiment of the present disclosure.

[0099] The roll pressing process 210 may represent a process of forming a film 218 based on film powder 216 using a first roller 212 and a second roller 214. The film powder 216 may correspond to or include the first active material particles 110 described above with reference to Figure 1 The first active material particles 110 described.

[0100] In an embodiment, the membrane powder 216 may include at least one of a conductive material or an adhesive. The conductive material may include any of the above-described conductive materials. For example, the conductive material may include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and / or carbon nanotube, or silicon-based materials. For example, the conductive material may be natural graphite, artificial graphite, or a silicon-based material.

[0101] In addition, the adhesive may include any of the above-described adhesive materials. The adhesive may include polytetrafluoroethylene (PTFE). However, the present disclosure is not limited thereto, and any suitable conductive material and / or adhesive for manufacturing a dry electrode membrane as would be understood by those of ordinary skill in the art may be utilized.

[0102] In an embodiment, the conductive material may be the same as the conductive material used in the process of manufacturing a dry electrode membrane to be described in more detail below Figure 8 Similarly, the adhesive may be the same as the adhesive used in the process of manufacturing a dry electrode membrane to be described in more detail below Figure 8 In addition, the membrane powder 216 may include at least some of the conductive material and the adhesive used in the process of manufacturing a dry electrode membrane. These will be described in more detail below with reference to Figure 8 more detail.

[0103] The rolling process 210 may be performed using the first roller 212 and the second roller 214. In this case, the first roller 212 and the second roller 214 may have different rotational speeds (RPMs) from each other. For example, the ratio of the rotational speeds of the first roller 212 and the second roller 214 may range from 1:1 to 1:20. According to the ratio of the rotational speeds of the rollers, the diameters of the respective rollers may be adjusted to be different.

[0104] In an embodiment, the gap between the first roller 212 and the second roller 214 may be adjustable. More specifically, the gap between the first roller 212 and the second roller 214 may be adjusted to correspond to the thickness of the membrane 218. For example, the gap between the first roller 212 and the second roller 214 may be about 1 μm.

[0105] The rolling process 210 may be performed under various suitable conditions. For example, the membrane 218 may be formed at a rotational speed of about 5 rpm corresponding to the first roller 212 or the second roller 214. For example, the membrane 218 may be formed at a temperature ranging from 25°C to 200°C. More specifically, the membrane 218 may be formed at a temperature ranging from 25°C to 150°C. However, the present disclosure is not limited thereto, and the rolling process 210 may be performed under various suitable conditions that may be selected to form the membrane 218 based on the membrane powder 216.

[0106] The crushing process 220 may represent a process of crushing the film 218 manufactured by the roll pressing process 210 to form the film powder 224. In this case, the film 218 may be crushed using the crusher 222. More specifically, the crusher 222 may crush the film 218 by mechanical grinding. For example, the crusher 222 may be any one of a shear mill, a disk mill, a ball mill, a blade mill, a hammer mill, or a suitable combination of these devices.

[0107] The crushing process 220 may be carried out under various suitable conditions. For example, the rotational speed of the crusher 222 may range from 500 rpm to 2500 rpm. For example, the film 218 may be crushed using the crusher 222 for about 30 seconds. However, the present disclosure is not limited thereto, and various suitable methods may be selected to crush the film 218 to form the film powder 224.

[0108] The sieving process 230 may represent a process of sieving at least a part of the film powder 224 to obtain the second active material particles 234. In this case, the sieve 232 may be used to sieve at least a part of the film powder 224. The sieve 232 may include a plurality of through holes. The through holes may allow only the film powder having a desired size (e.g., a predetermined size) in all of the film powder 224 to pass through. The second active material particles 234 may be obtained by sieving only the film powder having a desired size (e.g., a predetermined size) based on the size of the through holes. The size (e.g., particle diameter) of the second active material particles 234 may be adjusted based on the size of the through holes. For example, if the size of the through holes is about 30 μm, the size of the second active material particles 234 may be less than 30 μm.

[0109] The second active material particles 234 may be manufactured by granulating (pelletizing) the first active material particles. For example, the first active material particles may be granulated by roll pressing the film powder 216 containing the first active material particles. In another example, the first active material particles may be granulated together with at least one of the conductive material or the binder by roll pressing the film powder 216 further including at least one of the conductive material or the binder. Subsequently, the film 218 containing the granulated first active material particles may be crushed, and the crushed film powder 224 may be sieved to obtain the second active material particles 234 corresponding to the granulated first active material particles.

[0110] By granulating the first active material particles of a smaller size, the second active material particles 234 of a relatively larger size may be obtained. In addition, the granulation of the first active material particles may be promoted by using at least one of the conductive material or the binder. Furthermore, by adjusting the size of the through holes of the sieve 232, the second active material particles 234 may be obtained in a state where the upper limit of the size of the particles is controlled (e.g., set). Therefore, the size of the active material particles may be adjusted.

[0111] Figure 3 A diagram showing a method for obtaining coated second active material particles 324 according to an embodiment of the present disclosure.

[0112] The coating process 310 may represent a process of mixing the second active material particles 316 with a conductive material to form a conductive material coating layer on the surface of the second active material particles 316.

[0113] More specifically, in the coating process 310, the second active material particles 316 and the conductive material 318 may be mixed with each other in a mixer 312 to form the conductive material coating layer. In this case, the mixer 312 may include a compression member 314. The compression member 314 may apply a shear force or a compression force to the conductive material 318 and the second active material particles 316. Referring to the right side of Figure 3 , the shear force or the compression force may cause the conductive material 318 to adhere to the surface of the second active material particles 316. As the shear force or the compression force is continuously applied, the conductive material 318 may be applied uniformly or substantially uniformly over the entire or substantially the entire surface of the second active material particles 316. As a result, a conductive material coating layer 322 may be formed on the surface of the second active material particles 316, thereby modifying (decorating) the surface of the second active material particles 316.

[0114] In an embodiment, the conductive material coating layer 322 may have a suitable thickness (e.g., a certain or predetermined thickness) capable of supporting the second active material particles 316. For example, the conductive material coating layer 322 may have a thickness ranging from 1 nm to 500 nm. However, the present disclosure is not limited thereto, and the conductive material coating layer 322 may have a suitable thickness (e.g., a certain or predetermined thickness) to maintain or substantially maintain the morphology of the second active material particles 316 and not hinder the movement of lithium ions.

[0115] In an embodiment, the conductive material may be the same as the conductive material used in the process of manufacturing a dry electrode film described in more detail below with reference to Figure 8 Alternatively or as another example, the conductive material may be the same as the conductive material contained in the film powder 216 described above with reference to Figure 2 . For example, the conductive material may be at least one of natural graphite, artificial graphite, or a silicon-based material.

[0116] The mixer 312 can be a device capable of mixing the second active material particles 316 and the conductive material 318. For example, the mixer can be a mechanical fusion mixer, a planetary mixer, an extruder, etc. However, the present disclosure is not limited thereto, and any suitable device capable of mixing the second active material particles 316 and the conductive material 318 while applying a shear force or a compressive force can be used as the mixer 312.

[0117] In an embodiment, the mixer 312 containing the second active material particles 316 and the conductive material 318 can be rotated under various suitable conditions to form the coating layer. For example, the mixer 312 can be rotated at a rotational speed ranging from 3000 rpm to 15000 rpm to mix the second active material particles 316 and the conductive material 318 with each other. For example, the second active material particles 316 and the conductive material 318 can be mixed with each other at a temperature ranging from 25°C to 150°C. For example, the mixer 312 can be rotated at a rotational speed of about 5000 rpm for about 2 minutes to mix the second active material particles 316 and the conductive material 318 with each other. However, the present disclosure is not limited thereto, and various suitable conditions can be selected to sufficiently form the conductive material coating layer 322 on the surface of the second active material particles 316.

[0118] By forming the conductive material coating layer 322 on the surface of the second active material particles 316, the morphology of the second active material particles 316 can be more stabilized. For example, when the second active material particles 316 are used in the process of manufacturing the dry electrode film, each second active material particle 316 can collide with other particles, and the morphology of the second active material particles 316 may not be maintained. However, in some embodiments, the conductive material coating layer 322 can protect the second active material particles 316 from the influence of collision with other particles, thereby preventing or substantially preventing the deformation or damage of the second active material particles 316.

[0119] Figure 4 A diagram showing an example of a rolling process including a first rolling process 410 and a second rolling process 420 according to an embodiment of the present disclosure.

[0120] The first rolling process 410 can form the first film 414 by rolling the first film powder 412. The first film powder 412 can include first active material particles (e.g., Figure 1 the first active material particles 110). The second rolling process 420 can form the second film 424 by rolling the second film powder 422. The second film powder 422 can include the coated second active material particles (e.g., Figure 1 the coated second active material particles 130).

[0121] In the first rolling process 410 and the second rolling process 420, the first film 414 and the second film 424 may be formed in the form of self-supporting films. The self-supporting films will be described in more detail below with reference to Figure 8 In addition, the first rolling process 410 and the second rolling process 420 may be different from the rolling process 210 described above with reference to Figure 2 That is, the first rolling process 410 and the second rolling process 420 may be provided not for obtaining the second active material particles, but for forming the first film 414 and the second film 424 to evaluate the characteristics of the first film 414 and the second film 424.

[0122] In an embodiment, each of the first film powder 412 and the second film powder 422 may additionally include (e.g., additionally contain) at least one of a conductive material or a binder. At least one of the conductive material or the binder may contribute to the formation of the first film 414 and the second film 424. For example, at least one of the conductive material or the binder may help the particles contained in the first film powder 412 and the second film powder 422 to agglomerate.

[0123] The rollers 430 may be used in the first rolling process 410 and the second rolling process 420. The conditions and environments in which the rollers 430 are used in the first rolling process 410 and the second rolling process 420 may be the same as each other. For example, the gap between the rollers 430, the rotation speed ratio of the rollers 430, the temperature, etc. may be the same in the first rolling process 410 and the second rolling process 420.

[0124] For example, the first active material particles included in the first film 414 may be relatively small in size, and thus, may have a high cohesive force between the particles. In addition, the first active material particles in the first film 414 may be densely packed. As a result, in the first film 414, the density may be relatively high, the particle size may be relatively small, and the specific surface area may be relatively large. On the other hand, the second active material particles included in the second film 424 may be relatively large in size, and thus, may have a low cohesive force between the particles. In addition, the second active material particles in the second film 424 may be loosely arranged. As a result, in the second film 424, the density may be relatively low, the particle size may be relatively large, and the specific surface area may be relatively small. More details regarding the characteristics of the first film 414 and the second film 424 will be described below with reference to Figure 7 More details regarding the characteristics of the first film 414 and the second film 424 will be described below with reference to

[0125] Figure 5 A schematic diagram showing an example of a film according to an embodiment of the present disclosure.

[0126] The first schematic diagram 510 may show the first film (e.g., Figure 4The arrangement of the particles contained in the first film (414). The second schematic diagram 520 may show the arrangement of the particles contained in the second film (e.g., Figure 4 the second film (424)).

[0127] In an embodiment, the first film may include first active material particles 512 and a binder 514. The second film may include coated second active material particles 522 and a binder 514. The binder 514 included in the first film and the binder 514 included in the second film may correspond to the same material.

[0128] When roll-pressed with the first active material particles 512, the binder 514 in the first film may fibrillate into fine fiber strands (bundles). Similarly, when roll-pressed with the coated second active material particles 522, the binder 514 in the second film may fibrillate into fine fiber strands. The binder 514 in the form of fine fiber strands may support the first active material particles 512 (or the coated second active material particles 522) to maintain or substantially maintain the film shape in the first film (or the second film).

[0129] Referring to Figure 5 the first schematic diagram 510, the first active material particles in the first film may be densely packed. Additionally, there may be few voids (e.g., corresponding to empty spaces) between the first active material particles in the first film. Even if there are voids, the size of the voids may correspond to the size of the first active material particles. Referring to Figure 5 the second schematic diagram 520, the coated second active material particles in the second film may be loosely arranged. Additionally, there may be many voids 524 between the coated second active material particles in the second film. For example, the size of the voids may correspond to the size of the coated second active material particles.

[0130] Due to the presence of voids 524 in the second film, the cohesion between the coated second active material particles in the second film may be lower than the cohesion between the first active material particles in the first film. Additionally, compared to those of the first film, the second film may have a smaller specific surface area and a lower density because the coated second active material particles may be more loosely arranged in the second film. As a result, the second film may be relatively more flexible than the first film.

[0131] Figure 6 A photograph showing an example of a film according to an embodiment of the present disclosure.

[0132] The first image 610 shows the appearance of the first film, and the second image 620 shows the appearance of the second film. The first film may be formed based on a first film powder including (e.g., containing) the first active material particles, and the second film may be formed based on a second film powder including (e.g., containing) the second active material particles or the coated second active material particles. For example, the first film may correspond to the first film 410 described above with reference to Figure 4 and the second film may correspond to the second film 420 described above with reference to Figure 4 . Specifically, the first film and the second film are manufactured as follows.

[0133] (1) Mixing: First active material particles (LFP) + conductive material + binder (mass ratio 92:4:0.8)

[0134] (Blade mill → 2000 rpm / 10 min);

[0135] (2) Film formation (first film): First mixture (first active material particles (LFP) + conductive material + binder)

[0136] (Two-roll → speed ratio 1:1, temperature 100 °C);

[0137] (3) Crushing the first film: Obtaining second active material particles

[0138] (Blade mill → 1000 rpm / 30 s);

[0139] (4) Sieving a part of the film powder (formed by crushing the first film):

[0140] (Filtering out particles of 30 μm and smaller)

[0141] (5) Coating of conductive particles: Second active material particles + conductive material (mass ratio 92:4)

[0142] (Mechanical fusion → 5000 rpm / 2 min);

[0143] (6) Mixing: Coated second active material particles + binder (mass ratio 96:3.2)

[0144] (Blade mill → 2000 rpm / 30 s);

[0145] (7) Film formation (second film): Second mixture (coated second active material particles + binder)

[0146] (Two-roll → speed ratio 1:3, temperature 100 °C).

[0147] In one embodiment, the first film powder may include a first mixture comprising (e.g., containing) at least one of a conductive material (or conductive materials) or a binder (or binders) and the first active material particles, which may be obtained by a mixing process (e.g., the mixing process 820 described in more detail below). Similarly, the second film powder may include a second mixture comprising (e.g., containing) at least one of a conductive material (or conductive materials) or a binder (or binders) and the coated second active material particles, which may be obtained by a mixing process. In another embodiment, the first film powder may include a first film powder formed by subjecting the first mixture to a fibrillation process (e.g., the fibrillation process 830 described in more detail below) and a crushing process (e.g., the crushing process 840 described in more detail below). Similarly, the second film powder may include a second film powder formed by subjecting the second mixture to the fibrillation process and the crushing process. Figure 8 Figure 8 Figure 8

[0148] After forming the film, the film may be wound onto a roll. In this case, the film may have a level of flexibility (e.g., a certain or predetermined level) that is effectively wound onto the roll. Referring to the first image 610 and the second image 620 shown in Figure 6 , the first film may have a relatively large specific surface area and a relatively small particle size, which may result in reduced flexibility. On the other hand, the second film may have a relatively small specific surface area and a relatively large particle size, which may allow for greater flexibility. In this case, the first film may lack the desired flexibility to be wound onto the roll and may be damaged. On the other hand, the second film with greater flexibility may be successfully wound onto the roll. Thus, while the first film may not be suitable for use as an electrode film, the second film may be used as an effective electrode film.

[0149] The electrode film may be used in a roll-to-roll continuous process. It may be desirable to maintain or substantially maintain the film form for the roll-to-roll continuous process. As described above, by using the second film, the electrode film manufacturing process may be facilitated by maintaining or substantially maintaining the film form.

[0150] Figure 7 ​​​A diagram showing the characteristics of embodiments and comparative examples of a film according to one or more embodiments of the present disclosure. The first embodiment may be a film formed by roll-pressing a film powder including (e.g., containing) the coated second active material particles. The second embodiment may be a film formed by roll-pressing a film powder including (e.g., containing) the coated second active material particles and the conductive material. The third embodiment may be a film formed by roll-pressing a film powder including (e.g., containing) the coated second active material particles, the conductive material, and the binder.

[0151] The first comparative example may be a film formed by roll-pressing a film powder including (e.g., containing) the first active material particles. The second comparative example may be a film formed by roll-pressing a film powder including (e.g., containing) the first active material particles and the conductive material. The third comparative example may be a film formed by roll-pressing a film powder including (e.g., containing) the first active material particles, the conductive material, and the binder.

[0152] Figure 7 The figure in shows the average internal cohesion between particles according to each of the embodiments or embodiments and comparative examples. In Figure 7 For each embodiment, the average internal cohesion between particles may be represented by points on the bar graph. Referring to Figure 7 , in the first embodiment, the average internal cohesion between particles may be about 1 kPa, in the second embodiment, the average internal cohesion between particles may be about 2 kPa, and in the third embodiment, the average internal cohesion between particles may be about 3.5 kPa. Additionally, in the first comparative example, the average internal cohesion between particles may be about 3.6 kPa, in the second comparative example, the average internal cohesion between particles may be about 4 kPa, and in the third comparative example, the average internal cohesion between particles may be about 4.4 kPa. Therefore, the average internal cohesion between particles of the film manufactured based on the coated second active material particles may be relatively low. Specifically, the internal cohesion is measured as follows using a 302e device from Anton Paar GmbH. The bulk solid is placed and a normal stress is applied. The bulk solid is pre-sheared at a constant speed while the normal stress is applied, and then sheared at a constant speed under a decreasing normal stress until failure. When the sample is placed in the disk (bottom plate) and the paddle (top plate) of the 302e device from Anton Paar GmbH, it is squeezed and rotated, and the force (shearing force) applied by the paddle is measured. The higher the shearing force, the higher the value of the internal cohesion (the stress between particles) and the lower the fluidity.

[0153] More specifically, the coated second active material particles included in the second embodiment may have an average particle diameter (D50) of about 4.3 μm. Additionally, the specific surface area in the second embodiment may be about 5.7 m 2 / g. In contrast, the coated second active material particles in the second comparative example may have an average particle diameter (D50) of 1 μm. The specific surface area in the second comparative example may be 10.9 m 2 / g. In other words, the average particle diameter (D50) of the particles contained in the film having a lower average cohesive force between the particles may be relatively larger, while its specific surface area may be relatively smaller.

[0154] By examining the characteristics of the film as shown in Figure 7 , it can be observed that when the average cohesive force between the particles in the film is 3.5 kPa or less, such as 3 kPa or less, it promotes maintaining the form of the film. It can also be confirmed that when the specific surface area of the film is about 6 m 2 / g or less, it promotes maintaining the form of the film. Furthermore, it can be confirmed that when the average particle diameter of the active material particles contained in the film is about 4.5 μm or more, it promotes maintaining the form of the film.

[0155] Figure 8 FIG. is an example diagram showing a dry electrode film manufacturing process according to an embodiment of the present disclosure.

[0156] The dry electrode film manufacturing process according to an embodiment of the present disclosure may be carried out after the active material size control process 810. In other words, in the dry electrode film manufacturing process, the coated second active material particles obtained through the active material size control process are used as the active material in the subsequent processes 820 to 850. The active material size control process 810 may include a method of manufacturing active material particles according to an embodiment of the present disclosure. For example, the active material size control process 810 may include the rolling process 210, the crushing process 220, and the screening process 230 described above with reference to Figure 2 , and the coating process 310 described above with reference to Figure 3 .

[0157] The dry electrode film manufacturing process may include a mixing process 820, a fibrillation process 830, a pulverization process 840, and a rolling process 850. Through the mixing process 820, a mixture can be manufactured by mixing the active material, the binder, and the conductive material. In this case, the active material may include the following (for example, may be composed of the following): the coated second active material particles obtained through the active material size control process 810.

[0158] The mixture can be formed into a mixture powder through fibrillation process 830. More specifically, in fibrillation process 830, shear force can be applied to the binder included in the mixture to allow fibrillation of the binder. The fibrous binder can help bond or connect the active material and the conductive material included in the mixture to each other. For example, a kneader can be used to form the mixture powder.

[0159] The mixture powder can be formed into a crushed mixture powder through crushing process 840. For example, a crusher can be used for crushing process 840. By forming the crushed mixture powder, film formation of the mixture powder can be promoted.

[0160] The crushed mixture powder can be used to form a dry electrode film through roll pressing process 850. More specifically, the fibrous binder can promote the bonding or connection of the active material and the conductive material to each other to support or hold in the form of a film, thereby forming a dry electrode film. Additionally, the dry electrode film can be formed without using a separate solvent.

[0161] The dry electrode film can be formed in the form of a self - supporting film. The self - supporting film can refer to a film that can be formed independently without being laminated to a current collector. In other words, the dry electrode film can be formed in the form of a self - supporting film and then laminated to a current collector.

[0162] In an embodiment, the conductive material can be the same as the conductive material used in the roll pressing process 210 described above with reference to Figure 2 Similarly, the binder can be the same as that described above with reference to Figure 2The same binder is used in the described rolling process 210. For example, assuming that the total amount of the binder and the total amount of the conductive material used in the manufacture of the dry electrode are 100% and 100% respectively (e.g., % may refer to the mass ratio), the coated second active material particles can be obtained through the active material size control process 810 based on a film powder including (e.g., containing) about 20% of the conductive material and about 20% of the binder. Thereafter, the self-supporting film can be manufactured through the dry electrode manufacturing process based on a mixture including (e.g., containing) the coated second active material particles and the remaining about 80% of the conductive material and the remaining about 80% of the binder. In another example, the coated second active material particles can be obtained through the active material size control process 810 based on a film powder including (e.g., containing) about 50% of the conductive material and 100% of the binder. Thereafter, the self-supporting film can be manufactured through the dry electrode manufacturing process based on a mixture including (e.g., containing) the coated second active material particles and the remaining about 50% of the conductive material. In another example, the coated second active material particles can be obtained through the active material size control process 810 based on a film powder including (e.g., containing) about 50% of the conductive material and about 50% of the binder. Thereafter, the self-supporting film can be manufactured through the dry electrode manufacturing process based on a mixture including (e.g., containing) the coated second active material particles and the remaining about 50% of the conductive material and the remaining about 50% of the binder. In this way, the conductive material and the binder can be divided into appropriate proportions (e.g., certain or predetermined proportions) and utilized in each of the active material size control process 810 and the dry electrode film manufacturing process. However, the proportions of the conductive material and the binder are not limited thereto, and the proportions of the conductive material and the binder can be appropriately adjusted differently to obtain coated second active material particles suitable for the manufacture of a dry electrode film according to one or more embodiments of the present disclosure.

[0163] As described above, a dry electrode film manufactured through the dry electrode film manufacturing process using active material particles that have not undergone the active material size control process 810 may not be able to maintain the form of the film. On the other hand, a dry electrode film manufactured through the dry electrode film manufacturing process using active material particles that have undergone the active material size control process 810 according to one or more embodiments of the present disclosure can appropriately maintain the form of the film. In other words, the dry electrode film can be manufactured more smoothly using the active material size control process 810 according to one or more embodiments of the present disclosure.

[0164] Figure 9 A flowchart showing an example of a method 900 for manufacturing active material particles according to an embodiment of the present disclosure.

[0165] In an embodiment, method 900 may be carried out by a device for manufacturing active material particles. The device may include: a roller (e.g., the roller shown in Figure 2 ), a crusher (e.g., the crusher shown in Figure 2 ), a sieve (e.g., the sieve shown in Figure 2 ), and a mixer (e.g., the mixer shown in Figure 3 ). Additionally, a dry electrode film including (e.g., containing) active material particles prepared by method 900 may be provided. The specific surface area of the dry electrode film may range from 0.1 m 2 / g to 6 m 2 / g.

[0166] Method 900 may begin, and the first active material particles may be roll-pressed by a roller to form film S910. The first active material particles may correspond to positive electrode active material particles or negative electrode active material particles. For example, the first active material particles may correspond to a compound based on lithium iron phosphate. In an embodiment, the average particle size (D50) of the first active material particles may range from 0.1 μm to 3 μm.

[0167] In an embodiment, the roller may include a first roller and a second roller. The film may be formed by roll-pressing the first active material particles using the first roller and the second roller. In this case, the ratio of the rotational speeds between the first roller and the second roller may range from 1:1 to 1:20. Additionally, the film may be formed by roll-pressing the first active material particles at a temperature ranging from 25°C to 200°C. For example, a mixture including (e.g., containing) at least one of a conductive material (or multiple conductive materials) or an adhesive (or multiple adhesives) and the first active material particles may be prepared. The mixture may be roll-pressed to form the film. For example, the adhesive may correspond to polytetrafluoroethylene (PTFE). For example, the conductive material may include at least one of natural graphite, artificial graphite, or a silicon-based material.

[0168] The formed film may be crushed using a crusher to manufacture film powder S920.

[0169] In an embodiment, the film powder may be formed using a crusher, such as a shear mill, a disk mill, a ball mill, a blade mill, or a hammer mill.

[0170] The second active material particles S930 can be obtained by sieving at least a portion of the membrane powder using a sieve, and method 900 can end. The average particle size (D50) of the second active material particles can be greater than the average particle size (D50) of the first active material particles. Additionally, the grain size of individual second active material particles can be greater than the grain size of individual first active material particles. For example, the average particle size (D50) of the second active material particles can range from 4.5 μm to 30 μm.

[0171] In an embodiment, the conductive material coating layer can be formed on the surface of each of the second active material particles by mixing the second active material particles and the conductive material with each other using the mixer. More specifically, the conductive material coating layer can be formed at a temperature ranging from 25°C to 150°C. For example, the thickness of the conductive material coating layer can range from 1 nm to 500 nm.

[0172] However, the present disclosure is not limited to method 900 described above with reference to Figure 9 For example, one or more processes in the flowchart described above with reference to Figure 9 can be added, changed, or deleted. Additionally, the order of one or more processes can be modified differently, and / or one or more processes can be performed concurrently or substantially simultaneously with each other.

[0173] Although the present disclosure has been described above with respect to embodiments of the present disclosure, the present disclosure is not limited thereto. Those skilled in the art can make various modifications and variations within the spirit of the present disclosure and the scope of equivalents of the appended claims.

Claims

1. A method for manufacturing active material particles for a dry electrode, comprising: forming a film by roll-pressing first active material particles; forming film powder by crushing the formed film; and obtaining second active material particles by sieving at least a portion of the film powder, wherein an average particle size of the second active material particles is greater than an average particle size of the first active material particles.

2. The method according to claim 1, wherein the forming of the film comprises: preparing a mixture comprising at least one of a conductive material or a binder and the first active material particles; and roll-pressing the mixture to form the film.

3. The method according to claim 1, wherein the first active material particles correspond to positive electrode active material particles or negative electrode active material particles.

4. The method according to claim 1, wherein the first active material particles comprise a compound based on lithium iron phosphate.

5. The method according to claim 2, wherein the binder comprises polytetrafluoroethylene (PTFE).

6. The method according to claim 2, wherein the conductive material comprises at least one of natural graphite, artificial graphite, or a silicon-based material.

7. The method according to claim 1, wherein the average particle size of the first active material particles is in the range of 0.1 μm to 3 μm.

8. The method according to claim 1, wherein a grain size of each of the second active material particles is greater than a grain size of each of the first active material particles.

9. The method according to claim 7, wherein the average particle size of the second active material particles is in the range of 4.5 μm to 30 μm.

10. The method according to claim 1, further comprising: forming a conductive material coating layer on respective surfaces of the second active material particles by mixing the second active material particles with a conductive material.

11. The method according to claim 10, wherein a thickness of the conductive material coating layer is in the range of 1 nm to 500 nm.

12. The method according to claim 1, wherein the forming of the film comprises: roll-pressing the first active material particles by a first roll and a second roll to form the film, and wherein a rotational speed ratio of the first roll to the second roll ranges from 1:1 to 1:

20.

13. The method according to claim 1, wherein the forming of the film comprises: roll-pressing the first active material particles at a temperature in the range of 25°C to 200°C to form the film.

14. The method according to claim 1, wherein the forming of the film powder comprises: forming the film powder using at least one of a shear mill, a disk mill, a ball mill, a blade mill, or a hammer mill.

15. The method according to claim 10, wherein the forming of the conductive material coating layer comprises: forming the conductive material coating layer by using a mixer.

16. The method according to claim 10, wherein the forming of the conductive material coating layer comprises: forming the conductive material coating layer at a temperature in the range of 25°C to 150°C.

17. An apparatus for manufacturing active material particles, comprising: a roll configured to roll-press first active material particles to form a film; A crusher configured to crush the membrane to form membrane powder; and a sieve configured to screen at least a portion of the membrane powder to obtain second active material particles, wherein an average particle size of the second active material particles is larger than an average particle size of the first active material particles.

18. The apparatus according to claim 17, further comprising: a mixer configured to form a coating layer of the second active material particles using a conductive material.

19. A dry electrode membrane comprising active material particles manufactured by the method according to any one of claims 1-16.

20. The dry electrode film as described in claim 19, wherein the specific surface area of the dry electrode film is in the range of 0.1 m 2 / g to 6 m 2 / g.

Images