Electrode manufacturing apparatus and method of manufacturing electrode

Abstract

The present invention relates to an electrode manufacturing apparatus for performing a roll-to-roll process, the electrode manufacturing apparatus comprising: an unwinding unit in which an electrode current collector and a process film are sequentially wound on an outer peripheral surface of a supply roll, the unwinding unit being configured to continuously supply the electrode current collector; and an active material forming unit configured to form an active material layer on a surface of the electrode current collector, in which the electrode current collector includes a polymer resin layer and metal layers provided on both sides of the polymer resin layer, and the process film is formed of the same material as the polymer resin layer of the electrode current collector.

Description

Technical Field

[0001] The present invention relates to an electrode manufacturing apparatus and a method for manufacturing electrodes, and more particularly, to an electrode manufacturing apparatus and a method for manufacturing electrodes that can minimize the deformation of an electrode current collector comprising a polymer resin layer. Background Technology

[0002] With the technological advancements and increasing demands for electric vehicles and energy storage systems (ESS), the demand for batteries as energy sources has also increased significantly. Therefore, research is underway to develop batteries that can meet various requirements. In particular, active research is being conducted on lithium-ion secondary batteries that offer excellent lifespan and cycle characteristics, as well as high energy density, for use as power sources in these devices.

[0003] However, in lithium-ion batteries, a rapid temperature rise in the electrodes can occur due to both thermal and physical factors. Thermal factors include overcharging or overloading caused by misuse or malfunction of the charger. Physical factors include a rapid temperature rise in the electrodes when an internal short circuit occurs due to damage to the separator caused by external impact, leading to contact between the negative and positive electrode materials. If the electrode temperature rises rapidly in this way, the battery becomes highly unstable due to reactions between the electrolyte and lithium or the generation of hydrogen and oxygen within the battery. The electrolyte solvent decomposes to produce gases, and these decomposition gases may ignite, potentially causing the battery to explode.

[0004] Conventional lithium-ion batteries contain only a single metal layer as the electrode current collector. Specifically, an aluminum single metal layer is used as the positive electrode current collector, and a copper single metal layer is used as the negative electrode current collector. However, because these single metal layers have very high electrical and thermal conductivity, the time it takes for the battery to reach high temperatures instantaneously due to abnormal behavior is very short, and there is a problem of heat propagation due to thermal runaway.

[0005] Therefore, by using an electrode current collector (metallized film) containing a polymer resin layer disposed between two metal layers instead of a conventional electrode current collector, it is possible to reduce weight compared to electrode current collectors formed of metal, thus significantly improving the energy density per unit weight and improving safety by preventing short circuits between electrodes in the event of a fire.

[0006] Electrode manufacturing using a roll-to-roll process accounts for approximately 18% of battery manufacturing processes. It is a crucial process that determines most of the variables in battery design and is also a highly challenging process. It can be affected by various variables such as roller temperature control, circumferential speed ratio control between rollers, foreign object removal, and the overall supply speed control of the roll-to-roll process.

[0007] In the electrode manufacturing process using this roll-to-roll process, when using an electrode current collector with a polymer resin layer between two metal layers, the polymer resin layer and the metal layer have different properties, such as different glass transition temperatures and different tensile strengths. Therefore, when manufacturing electrodes by the roll-to-roll process, wrinkles are generated during the roll winding due to the shrinkage or stretching of the polymer resin layer, which seriously affects the quality of the electrode.

[0008] In addition, in order to find suitable process conditions to improve the formation of wrinkles, the electrode current collector film supplied must be discarded while searching for the conditions. Multilayer films have limitations in terms of disposal and recycling, and there is also the problem of reduced unit price competitiveness due to material consumption.

[0009] Therefore, there is a need for an electrode manufacturing technology that utilizes electrode current collectors (metallized films) with improved safety, which can ensure process continuity while achieving zero levels of waste electrode current collectors and maintaining excellent electrode quality. Summary of the Invention

[0010] Technical issues

[0011] One aspect of the present invention is to provide an electrode manufacturing apparatus and a method for manufacturing electrodes, which can manufacture electrodes by utilizing electrode current collectors (metallized films) comprising a polymer resin layer, and can improve quality by reducing the amount of electrode current collectors discarded due to wrinkles generated in the roll-to-roll process to zero.

[0012] Technical solution

[0013] [1] According to one embodiment, an electrode manufacturing apparatus using a roll-to-roll process is provided. The electrode manufacturing apparatus includes: The unfolding unit, wherein the electrode current collector and the process film are sequentially wound around the outer peripheral surface of the feed roller, is configured to continuously supply the electrode current collector; and An active material forming unit is configured to form an active material layer on the surface of an electrode current collector. The electrode current collector includes a polymer resin layer and metal layers disposed on both sides of the polymer resin layer, and The process film is formed from the same material as the polymer resin layer of the electrode current collector.

[0014] [2] According to the electrode manufacturing apparatus described in [1] above, the length ratio of the electrode current collector to the process film can be in the range of 1.5:1 to 3.5:1.

[0015] [3] According to the electrode manufacturing apparatus described above [1] and / or [2], the process film can be longer than the total production line length of the roll-to-roll process.

[0016] [4] The electrode manufacturing apparatus according to at least one of [1] to [3] above, wherein the polymer resin layer may include at least one of the following substances: polyester resin, epoxy resin, phenolic resin, melamine resin, polyurethane resin, silicone resin, vinyl acetate resin, rubber resin, acrylic resin and polyether polyurethane resin.

[0017] [5] The electrode manufacturing apparatus according to at least one of [1] to [4] above, wherein the metal layer may include at least one of the following substances: copper, stainless steel, aluminum, nickel, titanium, heat-treated carbon and aluminum-cadmium alloy.

[0018] [6] An electrode manufacturing apparatus according to at least one of [1] to [5] above, wherein the process film has a surface coated with a low alcohol or a surface treated with room temperature plasma.

[0019] [7] The electrode manufacturing apparatus according to at least one of [1] to [6] above, wherein the electrode manufacturing apparatus may further include a winding unit configured to wind an electrode current collector having an active material layer disposed thereon into a roll.

[0020] [8] The electrode manufacturing apparatus according to at least one of [1] to [7] above, wherein the active material forming unit may comprise: An active material coating unit, wherein the active material coating unit coats an active material slurry onto the surface of an electrode current collector; and A drying unit that dries the active material coated onto the electrode current collector.

[0021] [9] The electrode manufacturing apparatus according to at least one of [1] to [8] above, wherein the active material forming unit may comprise: A powdering unit, wherein the powdering unit manufactures a powder containing an active material; and A calendering unit that calenders powder rolls to produce a self-standing film.

[0022]

[10] The electrode manufacturing apparatus according to at least one of [1] to [9] above, wherein the thickness ratio of the metal layers disposed on both sides of the polymer resin layer to the polymer resin layer can be independently 1:1 to 1:15.

[0023]

[11] The electrode manufacturing apparatus according to at least one of [1] to

[10] above, wherein the thickness of the polymer resin layer and the process film can each be from 3 μm to 20 μm.

[0024]

[12] The electrode manufacturing apparatus according to at least one of [1] to

[11] above, wherein the thickness of the metal layers disposed on both sides of the polymer resin layer can be independently 0.2 μm to 5 μm.

[0025]

[13] According to another embodiment, a method for manufacturing an electrode including a roll-to-roll process is provided, the method comprising the following steps: Step S1: Starting from the unfolding unit in which the electrode current collector and the process film are sequentially wound on the outer peripheral surface of the roller, guide the process film first, prior to the electrode current collector; Step S2: Collect data on the degree of deformation of the process membrane by using process conditions, including temperature, as variables during the guiding process membrane; Step S3: Extract the process conditions for non-deformation of the process film from the collected data; and Step S4: Under the process conditions extracted in step S3, the active material layer is disposed on the electrode current collector while guiding the film of the electrode current collector.

[0026]

[14] According to the method described in

[13] above, in step S1, the process film can be guided to make it longer than the total production line length of the roll-to-roll process.

[0027] Beneficial effects

[0028] An electrode manufacturing apparatus according to one embodiment can manufacture electrodes by utilizing electrode current collectors (metallized films) comprising a polymer resin layer, and can improve electrode quality by reducing the amount of electrode current collectors discarded due to wrinkles generated in the roll-to-roll process to zero.

[0029] Furthermore, according to another embodiment, the method for manufacturing electrodes can pre-adjust process conditions to prevent wrinkles from forming in the electrode current collector (metallized film) containing the polymer resin layer, thus having the advantage that no electrode current collector needs to be consumed for electrode manufacturing.

[0030] Furthermore, since various functions of the polymer resin layer can be provided in the interval where the polymer resin layer moves independently, the quality can be improved by removing foreign matter from the surface of the guide roller before the main process. Attached Figure Description

[0031] Figure 1 This is a schematic diagram illustrating an electrode manufacturing apparatus according to one embodiment.

[0032] Figure 2 An unfolded unit of an electrode manufacturing apparatus according to one embodiment is shown.

[0033] Figure 3 This is a schematic diagram illustrating an electrode manufacturing apparatus including a wet process according to one embodiment.

[0034] Figure 4 This is a schematic diagram illustrating an electrode manufacturing apparatus including a dry process according to one embodiment. Detailed Implementation

[0035] The advantages and features of the present invention, as well as its implementation methods, will be illustrated by way of the embodiments described below in conjunction with the accompanying drawings. However, the present invention may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to make the invention comprehensive and complete, and to fully convey the scope of the invention to those skilled in the art. Furthermore, the invention is defined only by the scope of the claims. Throughout the text, the same reference numerals denote the same constituent elements.

[0036] Unless otherwise defined, all terms used herein (including technical and scientific terms) are intended to have the meaning understood by one of those skilled in the art. Furthermore, terms defined in common dictionaries should not be interpreted in an absurd or exaggerated manner unless explicitly defined.

[0037] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to limit the invention. In this specification, singular terms may include plural forms unless otherwise stated. It should also be understood that, when used in this specification, the terms “comprising” and / or “including” explicitly state the presence of the stated constituent element, but do not preclude the presence or addition of more than one other constituent element.

[0038] In this specification, unless otherwise expressly stated, when it is said that a part contains a certain element, it means that it may also contain other elements, not that it excludes other elements.

[0039] The expression "A and / or B" in this specification means A, or B, or A and B.

[0040] In this specification, unless otherwise expressly stated, "%" indicates weight.

[0041] The electrode manufacturing apparatus and method for manufacturing electrodes described in this specification include at least one of the following technical configurations, and may include any combination of technically feasible configurations from the following technical configurations.

[0042] Electrode manufacturing apparatus

[0043] In the following, the electrode manufacturing apparatus according to various embodiments will be described in detail with reference to the accompanying drawings. When adding reference numerals to the constituent elements of the various drawings, it should be noted that even if the same reference numerals appear in different drawings, they can be assigned to the same constituent elements as much as possible. Furthermore, in describing the present invention, detailed descriptions of related known configurations or functions will be omitted when it is determined that such detailed descriptions may obscure the essence of the invention.

[0044] An electrode manufacturing apparatus according to one embodiment performs a roll-to-roll process, wherein the electrode manufacturing apparatus includes: The unfolding unit, wherein the electrode current collector and the process film are sequentially wound around the outer peripheral surface of the feed roller, is configured to continuously supply the electrode current collector; and An active material forming unit is configured to form an active material layer on the surface of an electrode current collector.

[0045] In addition, the electrode current collector includes a polymer resin layer and metal layers disposed on both sides of the polymer resin layer, and the process film is formed of the same material as the polymer resin layer of the electrode current collector.

[0046] Figure 1 This is a schematic diagram showing an example of an electrode manufacturing apparatus 100, which will be described with reference to this example.

[0047] The electrode manufacturing apparatus 100 sequentially discharges and guides the process film and electrode current collector 112 from the unfolding unit 110, which sequentially winds the electrode current collector and process film therein. The guided electrode current collector 112 then passes through the active material forming unit 120, forming an active material layer on the current collector, thereby manufacturing the electrode 160. In this case, the electrode current collector 112 can pass through guide rollers 151 and 152 while moving towards the active material forming unit 120. The number of guide rollers can be adjusted appropriately according to process requirements. After passing through the active material forming unit 120, the electrode can be calendered by calendering rollers 140, and guide roller 153 can also be provided at its rear end.

[0048] The electrode manufacturing apparatus 100 may also include a winding unit 130 for winding the electrode 160 (which is an electrode current collector 112 on which an active material layer is disposed) into a roll. However, the electrode 160 may not be wound by a roller as in the winding unit 130, but may be cut while being moved by a means of movement such as a conveyor belt, and may be recycled in various ways in combination with the shape of the electrode assembly or subsequent battery assembly processes.

[0049] Electrode current collector

[0050] According to one embodiment, the electrode current collector 112 includes a polymer resin layer 1121 and metal layers 1122 and 1123 disposed on both sides of the polymer resin layer.

[0051] Conventional lithium-ion batteries contain only a single metal layer as the electrode current collector. Specifically, an aluminum single metal layer is used as the positive electrode current collector, and a copper single metal layer is used as the negative electrode current collector. However, because these single metal layers have very high electrical and thermal conductivity, the time it takes for the battery to reach high temperatures instantaneously due to abnormal behavior is very short, and there is a problem of heat propagation due to thermal runaway.

[0052] Therefore, by using an electrode current collector containing a polymer resin layer disposed between two metal layers instead of a conventional electrode current collector, it is possible to reduce weight compared to electrode current collectors formed of metal, thus significantly improving the energy density per unit weight and improving safety by preventing short circuits between electrodes in the event of a fire.

[0053] According to one embodiment, the polymer resin layer 1121 is a matrix resin, which prevents abnormal heat transfer between the electrode current collector and the electrode material mixture layer, and also serves to reduce the weight of the electrode current collector and mitigate external impacts.

[0054] The polymer resin layer may include, for example, at least one selected from the following substances: polyester resin, epoxy resin, phenolic resin, melamine resin, polyurethane resin, silicone resin, vinyl acetate resin, rubber resin, acrylic resin, and polyether polyurethane resin.

[0055] For example, the polymer resin layer may include at least one selected from the following substances: polyimide (PI), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyacrylonitrile (PAN), polyethylene (PE), polyamide (PA), and polypropylene (PP). Furthermore, the polymer resin layer may be a thermosetting resin or a photocurable resin, and may preferably include an ultraviolet-curable resin.

[0056] The polymer resin layer may contain photoinitiators such as benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanoceramic compounds, thioxanone compounds, or peroxide compounds; or photoinitiators such as amines or quinones, and may also contain curing accelerators such as amines, imidazoles, phosphorus compounds, boron compounds, and phosphoroboron curing accelerators. Furthermore, the polymer resin layer may contain thermal initiators, such as peroxides like azodicarbonamide, benzoyl peroxide, or acetyl peroxide.

[0057] The thickness of the polymer resin layer can range from 3 μm to 20 μm, and can be greater than 4 μm, 5 μm, or 6 μm, or less than 15 μm, 13 μm, 10 μm, or 8 μm. When the thickness of the polymer resin layer falls within the range of 3 μm to 20 μm, it represents an optimized thickness for heat transfer and can be maintained at a level that does not affect energy density. Therefore, the polymer resin layer offers the advantage of improving energy density while simultaneously reducing the weight of the electrode current collector and mitigating external shocks.

[0058] Metal layers 1122 and 1123 may comprise at least one material selected from copper, stainless steel, aluminum, nickel, titanium, heat-treated carbon, and aluminum-cadmium alloys. While not particularly limited, aluminum is preferred when forming the positive current collector, and copper is preferred when forming the negative current collector. Furthermore, fine irregularities may be formed on the surfaces of metal layers 1122 and 1123 to enhance adhesion to the electrode active material layer, and metal layers 1122 and 1123 may be used in various shapes such as films, sheets, foils, meshes, porous bodies, foams, and nonwoven fabrics.

[0059] The thickness of metal layers 1122 and 1123 can range from 0.2 μm to 5.0 μm, preferably 0.3 μm or more, 0.5 μm or more, or 0.6 μm or more, and can also be less than 3.0 μm, 2.0 μm or less, 1.5 μm or less, or 1.0 μm. When the thickness of the metal layer meets the above ranges, the metal layer can function as a carrier without any problems, and this thickness can be easily controlled in terms of physical properties, and can be an optimized thickness considering resistance or energy density.

[0060] The thickness ratio of the metal layer to the polymer resin layer can be in the range of 1:1 to 1:15, where this thickness ratio can be the ratio of either of the two metal layers, and the thicknesses of the two metal layers can be used independently of each other. This thickness ratio can be in the range of 1:1 to 1:15, preferably 1:4 to 1:12, and more preferably 1:6 to 1:10. When the thickness ratio of the first or second metal layer to the polymer resin layer meets the above-mentioned numerical range, there is an effect of increasing battery energy density while improving safety.

[0061] Expanding unit

[0062] An electrode manufacturing apparatus 100 according to one embodiment includes an unfolding unit 110, wherein an electrode current collector 112 and a process film 113 are sequentially wound around the outer peripheral surface of a supply roller 111, and the unfolding unit 110 is configured to continuously supply the electrode current collector 112.

[0063] Figure 2 The unfolding unit is shown, wherein the electrode current collector 112 is located on the inner side of the unfolding unit 110 by being wound around the outer peripheral surface of the supply roller 111, and the process film 113 is located on the outer side by being wound around the outer peripheral surface of the electrode current collector 112.

[0064] Because the unfolding unit 110 is constructed by winding the electrode current collector 112 and the process film 113 together onto the supply roller 111, the process film 113 wound at the rear end can be supplied first while setting the process conditions. Therefore, when supplying the electrode current collector 112, problems such as wrinkles occurring during roller winding or in the middle of the process can be prevented, thereby preventing the consumption / discarding of the electrode current collector. Furthermore, compared to the case where the process film 113 is wound onto a separate roller for supply testing, inefficient processes such as stopping the process and replacing the roller with a new one can be eliminated, thus providing significant advantages in terms of process.

[0065] In the electrode manufacturing apparatus 100, the process film 113 wound on the outer side of the unfolding unit 110 is formed of the same material as the polymer resin layer 1121 of the electrode current collector 112 wound on the inner side.

[0066] When constructing the unfolding unit 110, the unfolding unit 110 can be easily manufactured by forming metal layers 1122 and 1123 only on a portion of the polymer resin layer 1121. Furthermore, when extracting optimization conditions by using process conditions as variables, the accuracy of the process and the quality of the electrode can be ensured by using the same material as the polymer resin layer of the actual electrode current collector.

[0067] The length ratio of the electrode current collector to the process membrane can range from 1.5:1 to 3.5:1. The length of the electrode current collector used can be approximately 1.5 to 3.5 times the length of the process membrane, preferably more than 1.6, 1.7, 1.8, or 2.0 times, and less than 3.4, 3.3, 3.2, 3.1, or 3.0 times. Therefore, process conditions that improve electrode quality can be extracted as accurately as possible. The above ranges take into account the length of the process membrane consumed and the length of the process membrane required to extract the process conditions.

[0068] The process membrane can be at least longer than the total production line length of the roll-to-roll process used. Process conditions can be extracted without running the entire process, but to extract more accurate process conditions, it may be necessary to supply a process membrane with a length equivalent to at least the entire process length.

[0069] Process films can have surfaces coated with low alcohols or surfaces treated with room temperature plasma. Process films can be used to extract process conditions to minimize defects before using electrode current collectors (metallized films) in actual electrode manufacturing apparatuses, but process films are not limited to this function. They can also be used to remove foreign matter present on individual rollers in roll-to-roll processes by coating with low alcohols or treating with room temperature plasma, and can be used for a variety of functions.

[0070] Active material forming unit

[0071] According to one embodiment, electrode manufacturing apparatuses 200 and 300 include units for performing roll-to-roll processes, wherein they respectively include active material forming units 220 and 320 for forming active material layers on the surface of electrode current collector 112.

[0072] like Figure 3 As shown, the electrode manufacturing apparatus 200 can use a wet method, wherein the active material forming unit 220 includes: An active material coating unit 221 coats a slurry containing an active material onto the surface of an electrode current collector; and Drying unit 222 dries the active material coated on the electrode current collector.

[0073] In the active material forming unit 220, the following steps can be performed: a slurry containing an electrode active material, a conductive material, and a binder is coated onto the electrode current collector 112 by the active material coating unit 221, and the electrode current collector with the coated active material layer is manufactured into an electrode by the drying unit 222. The active material coating unit 221 can form an active material layer only on one side of the electrode current collector 112, or it can form an active material layer on both sides. Figure 3 The electrode manufacturing apparatus uses a wet method, in which, during the coating and drying of the slurry, in addition to Figure 3 In addition to the guide rollers 251, 252 and 253 shown, other guide rollers may be provided and used as needed.

[0074] As a method for coating or drying a slurry containing electrode active material, conventional methods used in the art can be used, but the present invention is not limited thereto.

[0075] In addition, such as Figure 4 As shown, the electrode manufacturing apparatus 300 can use a dry method, wherein the active material forming unit 320 includes: Powdering unit 321, said powdering unit 321 manufactures powder containing active material; and Calendering unit 322 calenders powder rolls to produce self-standing film 370.

[0076] The dry process is a solvent-free process in which, after mixing the electrode active material, conductive material and binder and applying shear force to form agglomerates, the agglomerates can be ground and then calendered to produce a self-standing membrane 370. In this case, the membrane can be bonded to the electrode current collector 112 by lamination. Furthermore, since the dry process can proceed from the pre-pressing process of the ground agglomerate powder to the calendering process through a roll-to-roll process, an appropriate number of guide rollers 354 and 355 can be set at appropriate locations.

[0077] Methods for manufacturing electrodes

[0078] According to another embodiment, a method for manufacturing an electrode is provided, wherein the method for manufacturing an electrode can be an electrode manufacturing method using the electrode manufacturing apparatus described above.

[0079] The method for manufacturing electrodes is characterized in that the method includes: Step S1: Starting from the unfolding unit in which the electrode current collector and the process film are sequentially wound on the outer peripheral surface of the roller, guide the process film first, prior to the electrode current collector; Step S2: Collect data on the degree of deformation of the process membrane by using process conditions, including temperature, as variables during the guiding process membrane; Step S3: Extract the process conditions for non-deformation of the process film from the collected data; and Step S4: Under the process conditions extracted in step S3, the active material layer is disposed on the electrode current collector while guiding the film of the electrode current collector.

[0080] In step S2, all possible conditions under which the polymer resin layer of the electrode current collector may be affected by heat can be considered. Specifically, the conditions of the heat treatment chamber or the temperature conditions of the heating roller during the drying of the electrode can be considered.

[0081] When using the above manufacturing method, since the process conditions can be optimized by using the process film in advance, the defect rate can be significantly reduced. Furthermore, in order to extract more optimized process conditions, the process film can be controlled to be longer than the total production line length of the roll-to-roll process in step S1.

[0082] In the above manufacturing method, since the description of the electrode current collector and the process film, as well as the description of the method of disposing of the active material layer on the electrode current collector, are the same as the description of the electrode manufacturing apparatus, their descriptions are omitted.

[0083] Lithium secondary batteries

[0084] A lithium secondary battery may comprise an electrode assembly impregnated with an electrolyte within a pouch, cylindrical, or prismatic battery casing. The electrode assembly includes electrodes and may include electrodes manufactured using an electrode manufacturing apparatus according to an embodiment of the invention.

[0085] A positive electrode, a separator, and a negative electrode are sequentially stacked in an electrode assembly, wherein the separator is disposed between the positive and negative electrodes. The positive electrode includes a positive current collector and a layer of positive active material stacked on the positive current collector, and the negative electrode includes a negative current collector and a layer of negative active material stacked on the negative current collector. At least one of the positive and negative electrodes can be manufactured by the electrode manufacturing apparatus of the present invention described above.

[0086] positive electrode

[0087] The metal layer of the positive electrode current collector can include a highly conductive metal, and there are no particular limitations, as long as it is non-reactive within the battery's voltage range and the positive electrode active material layer can easily adhere to it. As a positive electrode current collector, materials such as stainless steel, aluminum, nickel, titanium, sintered carbon, or aluminum or stainless steel with a surface treatment of carbon, nickel, titanium, silver, etc., can be used. Furthermore, the thickness of the positive electrode current collector is typically from 3 μm to 500 μm, and fine irregularities can be formed on the surface of the current collector to improve the adhesion of the positive electrode active material. For example, the positive electrode current collector can be used in various shapes such as films, sheets, foils, meshes, porous bodies, foams, and nonwoven fabrics.

[0088] If necessary, in addition to the positive electrode active material, the positive electrode active material layer may optionally contain conductive materials and adhesives.

[0089] In this case, based on the total weight of the positive electrode active material layer, the content of the positive electrode active material can be from 80% to 99% by weight, more specifically from 90% to 98% by weight.

[0090] Conductive materials are used to provide conductivity to the electrodes. Any conductive material can be used without particular limitation, as long as it has suitable electronic conductivity and will not cause chemical changes in the battery. Specific examples of conductive materials include: graphite such as natural or artificial graphite; carbon materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal cracking black, and carbon fibers; powders or fibers of metals such as copper, nickel, aluminum, and silver; conductive tubes such as carbon nanotubes; conductive whiskers such as zinc oxide whiskers and potassium titanate whiskers; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and any one or a mixture of two or more thereof can be used. Based on the total weight of the positive electrode active material layer, the content of the conductive material can be from 0.01% by weight to 10% by weight, preferably from 0.1% by weight to 9% by weight, and more preferably from 0.1% by weight to 5% by weight.

[0091] The adhesive improves the adhesion between the positive electrode active material particles and the adhesion between the positive electrode active material and the current collector. Specific examples of the adhesive can be: polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, polymethyl methacrylate, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene propylene diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber, polyacrylic acid, and polymers in which hydrogen is replaced by lithium (Li), sodium (Na), or calcium (Ca), or various copolymers thereof, and any one or a mixture of two or more thereof can be used. Based on the total weight of the positive electrode active material layer, the adhesive content can be from 1% to 30% by weight, preferably from 1% to 20% by weight, more preferably from 1% to 10% by weight.

[0092] In addition to using the aforementioned positive electrode active materials, positive electrodes can be manufactured according to typical methods for manufacturing positive electrodes. Specifically, a positive electrode slurry composition prepared by dissolving or dispersing the positive electrode active material, along with optional binders, conductive materials, and dispersants in a solvent, is coated onto a positive electrode current collector, which can then be used to manufacture the positive electrode by drying and calendering the coated positive electrode current collector.

[0093] The solvent can be any solvent commonly used in the art and can include: dimethyl sulfoxide (DMSO), isopropanol, N-methylpyrrolidone (NMP), dimethylformamide (DMF), acetone, or water, and any one of them or a mixture of two or more thereof can be used. The amount of solvent used is sufficient if, taking into account the coating thickness and manufacturing yield of the slurry, the solvent can dissolve or disperse the positive electrode active material, conductive material, binder, and dispersant, and can result in a viscosity that provides excellent thickness uniformity during subsequent coating for manufacturing the positive electrode.

[0094] Alternatively, as another method, the positive electrode can be manufactured by casting the positive electrode slurry composition onto a separate carrier and then pressing the membrane layer separated from the carrier onto the positive electrode current collector.

[0095] diaphragm

[0096] The separator separates the negative and positive electrodes and provides a pathway for lithium ion movement. Any separator can be used without particular limitation, as long as it is typically used in lithium secondary batteries. In particular, separators with high electrolyte retention capacity and low resistance to electrolyte ion transfer can be used. Specifically, porous polymer membranes can be used, such as those made from polyolefin polymers like ethylene homopolymers, propylene homopolymers, ethylene / butene copolymers, ethylene / hexene copolymers, and ethylene / methacrylate copolymers; or laminates having two or more layers. Additionally, typical porous nonwoven fabrics can be used, such as nonwoven fabrics formed from high-melting-point glass fibers or polyethylene terephthalate fibers. Furthermore, coated separators containing ceramic components or polymer materials can be used to ensure heat resistance or mechanical strength, and separators with single-layer or multi-layer structures can optionally be used.

[0097] electrolytes

[0098] The electrolyte may include organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel polymer electrolytes, solid inorganic electrolytes or molten inorganic electrolytes that can be used to manufacture lithium secondary batteries, but the present invention is not limited thereto.

[0099] Electrolytes can contain organic solvents and lithium salts.

[0100] Any organic solvent can be used without particular limitation, as long as it serves as a medium through which ions participating in the battery electrochemical reaction can move. Specifically, the following substances can be used as the organic solvent: ester solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; ether solvents such as dibutyl ether or tetrahydrofuran; ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as benzene and fluorobenzene; or carbonate solvents such as dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); alcohol solvents such as ethanol and isopropanol; nitriles such as R-CN (where R is a linear, branched, or cyclic C2-C20 hydrocarbon group and may contain double bonds, aromatic rings, or ether bonds); amides such as dimethylformamide; dioxolane such as 1,3-dioxolane; or sulfolane. Among these solvents, carbonate solvents are preferred, and more preferably are mixtures of cyclic carbonates (e.g., ethylene carbonate or propylene carbonate) with high ionic conductivity and high dielectric constant that can improve the charging / discharging performance of the battery and low viscosity linear carbonate compounds (e.g., ethyl methyl carbonate, dimethyl carbonate or diethyl carbonate).

[0101] Lithium salts can be used without particular restrictions, as long as they are compounds capable of providing lithium ions used in lithium secondary batteries. Specifically, the anion of the lithium salt can be at least one selected from the following anions: F - Cl - ,Br - I - NO3 - N(CN)2 - BF4 - CF3CF2SO3 - (CF3SO2)2N - (FSO2)2N - CF3CF2(CF3)2CO - (CF3SO2)2CH - (SF5)3C - (CF3SO2)3C - CF3(CF2)7SO3 - CF3CO2 - CH3CO2 - SCN - and (CF3CF2SO2)2N -The following substances can be used as the lithium salt: LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAlO4, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2, LiCl, LiI, or LiB(C2O4)2. The lithium salt can be used in concentrations ranging from 0.1 M to 4.0 M, preferably from 0.5 M to 3.0 M, and more preferably from 1.0 M to 2.0 M. If the concentration of the lithium salt is included within the above range, excellent electrolyte performance can be obtained because the electrolyte can have suitable conductivity and viscosity, and lithium ions can move efficiently.

[0102] To improve battery life characteristics, suppress battery capacity reduction, and improve battery discharge capacity, in addition to the electrolyte components mentioned above, the electrolyte may also contain at least one additive, such as: alkylene carbonate halide compounds like difluoroethylene carbonate, pyridine, triethyl phosphite, triethanolamine, cyclic ethers, ethylenediamine, (condensed) glycol dimethyl ethers, hexamethylphosphoric triamine, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted sulfadiazine ketones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, or aluminum trichloride. In this case, based on the total weight of the electrolyte, the additive content can be from 0.1% by weight to 10.0% by weight.

[0103] negative electrode

[0104] The negative electrode includes a negative electrode current collector and a layer of negative electrode active material disposed on the negative electrode current collector.

[0105] There are no particular restrictions on the metal layer of the negative electrode current collector, as long as it has high conductivity and will not cause chemical changes in the battery. Materials used include, for example, copper, stainless steel, aluminum, nickel, titanium, sintered carbon; copper or stainless steel with a surface treatment of carbon, nickel, titanium, silver, etc.; and aluminum-cadmium alloys. Furthermore, the thickness of the negative electrode current collector can typically range from 3 μm to 500 μm, and similar to the positive electrode current collector, fine irregularities can be formed on the surface of the current collector to improve the adhesion of the negative electrode active material. For example, the negative electrode current collector can be used in various shapes such as films, sheets, foils, meshes, porous bodies, foams, and nonwoven fabrics.

[0106] In addition to the negative electrode active material, the negative electrode active material layer may optionally include a binder and a conductive material.

[0107] Compounds capable of reversibly inserting and de-intercalating lithium can be used as anode active materials. Specific examples of anode active materials include: carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fibers, and amorphous carbon; (semi-)metallic materials that can form alloys with lithium, such as silicon (Si), aluminum (Al), tin (Sn), lead (Pb), zinc (Zn), bismuth (Bi), indium (In), magnesium (Mg), gallium (Ga), cadmium (Cd), Si alloys, Sn alloys, or Al alloys; and (semi-)metal oxides that can be doped and de-doped with lithium, such as SiO2. β (0<β<2), SnO2, vanadium oxide and lithium vanadium oxide; or composite materials containing (semi-)metallic materials and carbonaceous materials such as Si-C composite materials or Sn-C composite materials, and any one of them or a mixture of two or more thereof can be used. Furthermore, lithium metal films can be used as negative electrode active materials. In addition, both low-crystallinity carbon and high-crystallinity carbon can be used as carbon materials. Typical examples of low-crystallinity carbon can be soft carbon and hard carbon, and typical examples of high-crystallinity carbon can be irregular, planar, sheet-like, spherical or fibrous natural or artificial graphite, condensed graphite, pyrolytic carbon, mesophase pitch-based carbon fibers, mesophase carbon microspheres, mesophase pitch, and high-temperature sintered carbon such as coke derived from petroleum or coal tar pitch.

[0108] Based on the total weight of the negative electrode active material layer, the content of the negative electrode active material can be 80% to 99% by weight, 82% to 99% by weight, or 84% to 99% by weight.

[0109] Adhesives are components that facilitate the bonding between conductive materials, active materials, and current collectors. They are typically added in amounts ranging from 0.1% to 10% by weight, based on the total weight of the negative electrode active material layer. Examples of adhesives include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene propylene diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber, nitrile rubber, fluororubber, and various copolymers thereof.

[0110] Conductive materials are components used to further improve the conductivity of the negative electrode active material. Based on the total weight of the negative electrode active material layer, the content of the conductive material can be from 1% to 30% by weight, 1% to 20% by weight, or 1% to 10% by weight. There are no particular limitations on the conductive material, as long as it is conductive and will not cause adverse chemical changes in the battery. For example, conductive materials such as: graphite (natural or artificial); carbon black (acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermally cracked black); conductive fibers (carbon fiber or metal fiber); fluorocarbons; metal powders (aluminum and nickel powders); conductive whiskers (zinc oxide and potassium titanate whiskers); conductive metal oxides (titanium oxide); or polyphenylene derivatives.

[0111] The negative electrode active material layer can be manufactured by coating a negative electrode slurry composition, prepared by dissolving or dispersing the optional binder and conductive material in a solvent, onto a negative electrode current collector and drying the coated negative electrode current collector, or by casting the negative electrode slurry composition onto a separate carrier and then pressing the film layer separated from the carrier onto the negative electrode current collector.

[0112] In addition, the lithium secondary battery may optionally include: a battery container that houses an electrode assembly of a positive electrode, a separator, and a negative electrode; and a sealing member that seals the battery container.

[0113] Furthermore, because lithium-ion batteries consistently exhibit excellent discharge capacity, output characteristics, and capacity retention, they are suitable for: portable devices such as mobile phones, laptops, and digital cameras; and electric vehicles such as hybrid electric vehicles (HEVs).

[0114] Therefore, a battery module containing a lithium secondary battery as a unit cell and a battery pack containing the battery module are provided.

[0115] Battery modules or battery packs can be used as a power source for at least one medium to large-sized device from the following categories: power tools; electric vehicles, including electric vehicles (EVs), hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs); or energy storage systems.

[0116] Example

[0117] In the following description, embodiments of the invention will be described in detail in a manner readily practiced by those skilled in the art. However, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0118] Example 1

[0119] Aluminum metal is deposited on both sides of polyethylene terephthalate (PET) with a thickness of 4 μm to form a metal layer and a metal layer, which is used as an electrode current collector. The electrode current collector with the metal layer is wound on a feed roller with a length of 1,000 m, and a process film of PET film without a metal layer is wound on the feed roller with a length of 500 m to form an unfolding unit.

[0120] A positive electrode slurry was prepared by mixing positive electrode active material (NCM65 1520), conductive material (Li-435) and PVDF binder (KF9700, AD-c01) in N-methylpyrrolidone at a weight ratio of 96.5:1.5:2.0.

[0121] The process begins with the extrusion of the membrane from the unfolding unit. Optimized conditions are extracted while the temperature and tension are changed. Electrodes are manufactured by using the extracted conditions, starting from the discharge of the electrode current collector.

[0122] Comparative Example 1

[0123] Except that the above-mentioned process membrane is not used and only the electrode current collector is wound on the supply roller to form the unfolding unit, and the electrode is manufactured by changing the conditions twice during the manufacturing process while the electrode current collector is being discharged from the beginning, the unfolding unit and the positive electrode slurry are prepared in the same manner as in Example 1.

[0124] Experimental Example: Evaluation of Electrode Defect Rate and Machinability

[0125] Electrode defect rates were measured for Example 1 and Comparative Example 1.

[0126] [Table 1]

[0127] As shown in Table 1, when using the electrode manufacturing apparatus according to an embodiment of the present invention, since the conditions of the roll-to-roll process can be changed by the process film, it is possible to have the advantage of significantly reducing the defect rate during electrode manufacturing.

[0128] [Explanation of reference numerals in the attached figures]

[0129] 100, 200, 300: Electrode manufacturing equipment

[0130] 110, 210, 310: Expanding units

[0131] 111: Supply Roller

[0132] 112: Electrode Current Collector

[0133] 1121: Polymer resin layer

[0134] 1122, 1123: Metal layer

[0135] 113: Process membrane

[0136] 120, 220, 320: Active material forming units

[0137] 130, 230, 330: Winding unit

[0138] 140, 240, 340: Calendering rolls

[0139] 160: Electrode

[0140] 151, 152, 153, 251, 252, 253, 351, 352, 353, 354, 355: Guide rollers

Claims

1. An electrode manufacturing apparatus for performing a roll-to-roll process, The electrode manufacturing apparatus comprises: An unfolding unit, wherein an electrode current collector and a process film are sequentially wound around the outer peripheral surface of a supply roller, the unfolding unit being configured to continuously supply the electrode current collector; and An active material forming unit is configured to form an active material layer on the surface of the electrode current collector. The electrode current collector comprises a polymer resin layer and metal layers disposed on both sides of the polymer resin layer, and The process membrane is formed of the same material as the polymer resin layer of the electrode current collector.

2. The electrode manufacturing apparatus according to claim 1, wherein the length ratio of the electrode current collector to the process film is in the range of 1.5:1 to 3.5:

1.

3. The electrode manufacturing apparatus according to claim 1, wherein the process film is longer than the total production line length of the roll-to-roll process.

4. The electrode manufacturing apparatus according to claim 1, wherein the polymer resin layer comprises at least one selected from the following substances: polyester resin, epoxy resin, phenolic resin, melamine resin, polyurethane resin, silicone resin, vinyl acetate resin, rubber resin, acrylic resin, and polyether polyurethane resin.

5. The electrode manufacturing apparatus according to claim 1, wherein the metal layer comprises at least one selected from the group consisting of copper, stainless steel, aluminum, nickel, titanium, heat-treated carbon, and aluminum-cadmium alloy.

6. The electrode manufacturing apparatus according to claim 1, wherein the process film has a surface coated with a low alcohol or a surface treated with room temperature plasma.

7. The electrode manufacturing apparatus according to claim 1, further comprising a winding unit configured to wind the electrode current collector on which the active material layer is disposed into a roll.

8. The electrode manufacturing apparatus according to claim 1, wherein the active material forming unit comprises: An active material coating unit, wherein the active material coating unit coats an active material slurry onto the surface of the electrode current collector; and A drying unit dries the active material coated onto the electrode current collector.

9. The electrode manufacturing apparatus according to claim 1, wherein the active material forming unit comprises: A powdering unit, wherein the powdering unit manufactures a powder containing an active material; and A calendering unit that calenders the powder rolls to produce a self-standing film.

10. The electrode manufacturing apparatus according to claim 1, wherein the thickness ratio of the metal layers disposed on both sides of the polymer resin layer to the polymer resin layer is independently from 1:1 to 1:

15.

11. The electrode manufacturing apparatus according to claim 1, wherein the thickness of the polymer resin layer and the process film are each from 3 μm to 20 μm.

12. The electrode manufacturing apparatus according to claim 1, wherein the thickness of each of the metal layers disposed on both sides of the polymer resin layer is independently from 0.2 μm to 5 μm.

13. A method for manufacturing an electrode including a roll-to-roll process, the method comprising: Step S1: Starting from the unfolding unit in which the electrode current collector and the process film are sequentially wound on the outer peripheral surface of the roller, the process film is guided preferentially over the electrode current collector; Step S2: Collect data on the degree of deformation of the process film by using process conditions, including temperature, as variables during the guiding of the process film; Step S3: Extract the process conditions for the process membrane to remain undeformed from the collected data; and Step S4: Under the process conditions extracted in step S3, an active material layer is disposed on the electrode current collector while guiding the membrane of the electrode current collector.

14. The method according to claim 1, wherein, In step S1, the process film is guided to be longer than the total production line length of the roll-to-roll process.

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