Electrode manufacturing apparatus and electrode manufacturing method

Abstract

The present invention relates to an electrode manufacturing apparatus including a roll-to-roll process, wherein an electrode current collector and a process film are sequentially wound from the outer circumferential surface of a supply roller, and the apparatus includes an unwinding section for continuously supplying the electrode current collector and an active material forming section for forming an active material layer on the surface of the 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 made 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 an electrode manufacturing method, and more particularly to an electrode manufacturing apparatus and an electrode manufacturing method that can minimize the deformation of an electrode current collector containing a polymer resin layer. [Background technology]

[0002] As technological development and demand for electric vehicles and energy storage systems (ESS) increase, the demand for batteries as an energy source is rapidly rising, and consequently, research is being conducted on batteries that can meet a variety of requirements. In particular, there is a lot of research being done on lithium-ion secondary batteries that have high energy density while also possessing excellent lifespan and cycle characteristics, for use as power sources for such devices.

[0003] However, lithium secondary batteries can experience a rapid increase in electrode temperature due to thermal and physical factors. Thermal factors include overcharging or overloading due to misuse or malfunction of chargers, while physical factors include damage to the separation membrane due to external impact, causing an internal short circuit when the negative and positive electrode materials come into contact. When the electrode temperature rises so rapidly, the electrolyte and lithium react, and hydrogen and oxygen are generated inside the battery, making the battery extremely unstable. This can lead to the decomposition of the electrolyte solvent, generating gases, which can then ignite and cause the battery to explode.

[0004] Conventional lithium-ion batteries contain only a single metal layer as the electrode current collector; specifically, a single aluminum metal layer is used as the positive electrode current collector, and a single copper metal layer is used as the negative electrode current collector. However, because such single metal layers have very high electrical and thermal conductivity, the time it takes for them to reach high temperatures instantaneously during abnormal battery behavior is very short, raising concerns about thermal runaway and thermal propagation.

[0005] Therefore, by using an electrode current collector (metalized film) that includes a polymer resin layer interposed between two metal layers instead of a conventional electrode current collector, it is possible to reduce the weight compared to an electrode current collector made of metal, dramatically improve the energy density per unit weight, and enhance safety by short-circuiting the electrodes in the event of a fire.

[0006] On the other hand, the electrode manufacturing process using the roll-to-roll method accounts for approximately 18% of the battery manufacturing process. It is a crucial process in which most of the variables in battery design are determined, and it is a highly complex process in which various variables such as roll temperature control, peripheral speed ratio control between each roll, foreign matter removal, and overall travel speed control of the roll-to-roll process can have an impact.

[0007] In such a roll-to-roll electrode manufacturing process, when using an electrode current collector with a polymer resin layer interposed between two metal layers, the polymer resin layer and the metal layer have different glass transition temperatures and different tensile strengths, among other different characteristics. Therefore, during the manufacturing of electrodes by the roll-to-roll process, shrinkage or stretching of the polymer resin layer can cause wrinkles to form during roll winding, seriously affecting the quality of the electrodes.

[0008] Furthermore, in order to find appropriate process conditions to improve wrinkle formation, the electrode current collector film that has been used during the process must be discarded. However, there are limitations on the disposal and recycling of multilayer films, and this also leads to problems of reduced cost competitiveness due to material consumption.

[0009] Therefore, there is a need for electrode manufacturing technology that utilizes electrode current collectors, which are metallized films with improved safety, that can eliminate the waste of electrode current collectors despite maintaining an excellent level of electrode quality, while also ensuring the continuity of the process. [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The present invention aims to provide an electrode manufacturing apparatus and electrode manufacturing method that can manufacture electrodes using an electrode current collector which is a metallized film containing a polymer resin layer, thereby reducing the amount of electrode current collector waste due to wrinkle formation in the roll-to-roll process to zero and improving quality. [Means for solving the problem]

[0011] [1] According to one embodiment, an electrode manufacturing apparatus including a roll-to-roll process is provided, wherein an electrode current collector and a process film are sequentially wound from the outer circumferential surface of a supply roller, and the apparatus includes an unwinding section for continuously supplying the electrode current collector and an active material forming section for forming an active material layer on the surface of the 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 material of the process film is the same as the polymer resin layer of the electrode current collector.

[0012] [2] In the above [1], the electrode manufacturing apparatus may be such that the ratio of the lengths of the electrode current collector and the process film is 1.5:1 to 3.5:1.

[0013] [3] In the above [1] and / or [2], the electrode manufacturing apparatus may have a process film that is longer than the total length of the roll-to-roll process line.

[0014] [4] In at least one of the above [1] to [3], the electrode manufacturing apparatus may include one or more polymer resins selected from the group consisting of polyester resins, epoxy resins, phenolic resins, melamine resins, urethane resins, silicone resins, vinyl acetate resins, rubber resins, acrylic resins, and polyether urethane resins.

[0015] [5] In at least one of the above [1] to [4], the electrode manufacturing apparatus may be such that the metal layer contains at least one selected from the group consisting of copper, stainless steel, aluminum, nickel, titanium, heat-treated carbon, and aluminum-cadmium alloy.

[0016] [6] In at least one of the above [1] to [5], the electrode manufacturing apparatus may be such that the process film has a lower alcohol coated on its surface or its surface is treated with room temperature plasma.

[0017] [7] In at least one of the above [1] to [6], the electrode manufacturing apparatus may further include a winding unit for winding the electrode current collector on which the active material layer is disposed in a roll shape.

[0018] [8] In at least one of the above [1] to [7], the electrode manufacturing apparatus may be such that the active material forming unit includes an active material coating unit for applying an active material slurry to the surface of the electrode current collector and a drying unit for drying the active material applied on the electrode current collector.

[0019] [9] In at least one of the above [1] to [8], the electrode manufacturing apparatus may be such that the active material forming unit includes a powdering unit for manufacturing a powder containing an active material and a calendering unit for roll-calendering the powder to manufacture a self-supporting film.

[0020]

[10] In at least one of the above [1] to [9], the electrode manufacturing apparatus may be such that the metal layers disposed on both sides of the polymer resin layer are each independently such that the ratio of the thickness to the polymer resin layer is 1:1 to 1:15.

[0021]

[11] In at least one of the above [1] to

[10] , the electrode manufacturing apparatus may be such that the polymer resin layer and the process film have a thickness of 3 μm to 20 μm.

[0022]

[12] In at least one of the above [1] to

[11] , the metal layers disposed on both sides of the polymer resin layer may each independently have a thickness of 0.2 μm to 5 μm.

[0023]

[13] According to another embodiment, there is provided an electrode manufacturing method including a roll-to-roll process, the method including: a step (S1) of guiding a process film from a pay-out section in which an electrode current collector and the process film are sequentially wound around an outer peripheral surface of a roller, preferentially to the electrode current collector; a step (S2) of collecting, as data, a degree of deformation of the process film while using process conditions including temperature as variables while the process film is being guided; a step (S3) of extracting process conditions under which the process film does not deform from the collected data; and a step (S4) of disposing an active material layer on the current collector by guiding the electrode current collector under the process conditions extracted in step S3.

[0024]

[14] In the above

[13] , in step S1 of the electrode manufacturing method, the process film may be guided over the entire length of the line of the roll-to-roll process.

Advantages of the Invention

[0025] An electrode manufacturing apparatus according to an embodiment can manufacture an electrode by utilizing an electrode current collector that is a metallized film including a polymer resin layer, and can reduce the amount of waste of the electrode current collector due to the generation of wrinkles in the roll-to-roll process to zero and improve the quality of the electrode.

[0026] Further, an electrode manufacturing method according to another embodiment can preliminarily adjust process conditions under which wrinkles do not occur in an electrode current collector that is a metallized film including a polymer resin layer, and thereby has an advantage that the electrode current collector does not have to be consumed for manufacturing the electrode.

[0027] Furthermore, in sections where the polymer resin layer travels independently, various functionalities can be imparted to the polymer resin layer through processing, thereby removing foreign matter from the guide roll surface before the main process and improving quality. [Brief explanation of the drawing]

[0028] [Figure 1] This is a schematic diagram illustrating an electrode manufacturing apparatus according to one embodiment. [Figure 2] This shows the unwinding section of an electrode manufacturing apparatus according to one embodiment. [Figure 3] This is a schematic diagram illustrating an electrode manufacturing apparatus that includes a wet process according to one embodiment. [Figure 4] This is a schematic diagram illustrating an electrode manufacturing apparatus that includes a dry process according to one embodiment. [Modes for carrying out the invention]

[0029] The advantages and features of the present invention, as well as methods for achieving them, will become apparent with reference to the embodiments described below in detail, along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and can be realized in a variety of different forms. These embodiments are provided merely to complete the disclosure of the present invention and to allow a person with ordinary skill in the art to fully understand the scope of the invention, and the present invention is defined solely by the scope of the claims. Throughout the specification, the same reference numerals indicate the same components.

[0030] Unless otherwise defined, all terms used herein (including technical and scientific terms) are intended to be understood in a sense commonly understood by those with ordinary skill in the art to which this invention pertains. Furthermore, terms defined in commonly used dictionaries should not be interpreted ideally or excessively unless otherwise clearly defined.

[0031] The terms used herein are for illustrative purposes only and do not limit the invention. In this specification, singular forms include plural forms unless otherwise specified in the statement. The terms “includes,” “has,” and “equips” as used herein do not preclude the presence or addition of one or more other components in addition to the components mentioned.

[0032] In this specification, if a part is said to include a component, it means that, unless otherwise stated, it may include other components rather than excluding them.

[0033] In this specification, the term "A and / or B" means A, B, or A and B.

[0034] In this specification, "%" means weight percent unless otherwise explicitly indicated.

[0035] The electrode manufacturing apparatus and electrode manufacturing method described herein include at least one of the technical configurations described below, and may include any combination of technically feasible configurations from the following technical configurations.

[0036] Electrode manufacturing equipment Hereinafter, electrode manufacturing apparatuses according to each embodiment will be described in detail with reference to the drawings. When assigning reference numerals to the components in each drawing, identical components may have the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, when describing the present invention, if it is determined that a specific description of a related known configuration or function would obscure the gist of the present invention, such detailed description may be omitted.

[0037] An electrode manufacturing apparatus according to one embodiment includes a roll-to-roll process, in which an electrode current collector and a process film are sequentially wound from the outer circumferential surface of a supply roller, and includes an unwinding section for continuously supplying the electrode current collector and an active material forming section for forming an active material layer on the surface of the electrode current collector.

[0038] Furthermore, 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 made of the same material as the polymer resin layer of the electrode current collector.

[0039] Figure 1 is a schematic diagram showing an example of the electrode manufacturing apparatus 100, and the electrode manufacturing apparatus 100 will be explained with reference to it.

[0040] In the electrode manufacturing apparatus 100, the process film and electrode current collector are sequentially discharged and guided from the unwinding section 110 where the electrode current collector 112 and process film are sequentially wound. The guided electrode current collector 112 then passes through the active material forming section 120, where an active material layer is formed on the current collector, thereby manufacturing the electrode 160. Here, the electrode current collector 112 can pass through guide rollers 151 and 152 while traveling through the active material forming section 120. The number of guide rollers can be appropriately applied according to the requirements of the process. After passing through the active material forming section 120, the electrode can be rolled by a rolling roller 140, and a guide roller 153 can also be provided in the subsequent stage.

[0041] The electrode manufacturing apparatus 100 may further include a winding section 130 for winding the electrode 160, which is an electrode current collector 112 on which the active material layer is arranged, into a roll shape. However, the electrode 160 may be cut while being moved by a moving means such as a conveyor belt, rather than being wound on a roll as in the winding section 130, and can be recovered in various ways in conjunction with the shape of the electrode assembly and the subsequent battery assembly process.

[0042] Electrode current collector According to one embodiment, the electrode current collector 112 includes a polymer resin layer 1121 and metal layers 1122 and 1123 arranged on both sides of the polymer resin layer.

[0043] Conventional lithium-ion batteries contain only a single metal layer as the electrode current collector; specifically, a single aluminum metal layer is used as the positive electrode current collector, and a single copper metal layer is used as the negative electrode current collector. However, because such single metal layers have very high electrical and thermal conductivity, the time it takes for them to reach high temperatures instantaneously during abnormal battery behavior is very short, raising concerns about thermal runaway and thermal propagation.

[0044] Therefore, by using an electrode current collector that includes a polymer resin layer interposed between two metal layers, instead of a conventional electrode current collector, it is possible to reduce the weight compared to an electrode current collector made of metal, dramatically improve the energy density per unit weight, and improve safety by short-circuiting the electrodes in the event of a fire.

[0045] According to one embodiment, the polymer resin layer 1121 is a matrix resin that prevents abnormal heat transfer between the electrode current collector and the electrode mixture layer, and also plays a role in reducing the weight of the electrode current collector and mitigating external shocks.

[0046] The polymer resin layer may include, for example, one or more resins selected from the group consisting of polyester resins, epoxy resins, phenolic resins, melamine resins, urethane resins, silicone resins, vinyl acetate resins, rubber resins, acrylic resins, and polyether urethane resins.

[0047] For example, the polymer resin layer may contain one or more materials selected from the group consisting of 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 it is preferable that it contains an ultraviolet-curable resin.

[0048] The polymer resin layer may contain photoinitiators such as benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, and peroxide compounds, or photoinitiators such as amines and quinones, and may further contain curing accelerators such as amine-based, imidazole-based, phosphorus-based, boron-based, and phosphorus-boron-based agents. It may also contain thermal initiators such as azobisnitrile, benzoyl peroxide, and acetyl peroxide peroxides.

[0049] The polymer resin layer may have a thickness of 3 μm to 20 μm, but may also be 4 μm or more, 5 μm or more, or 6 μm or more, and may be 15 μm or less, 13 μm or less, 10 μm or less, or 8 μm or less. When the thickness of the polymer resin layer is within the range of 3 μm to 20 μm, it is a thickness optimized for heat transfer and is at a level that does not affect energy density, thereby having the advantage of improving energy density while reducing the weight of the electrode current collector and mitigating external shocks.

[0050] The metal layers 1122 and 1123 may contain one or more selected from the group consisting of copper, stainless steel, aluminum, nickel, titanium, heat-treated carbon, and aluminum-cadmium alloy. While not particularly limited, it is preferable to include aluminum when forming a positive electrode current collector, and to include copper when forming a negative electrode current collector. Furthermore, the metal layers 1122 and 1123 can have fine irregularities formed on their surfaces to strengthen the bonding force with the electrode active material layer, and can be used in various forms such as films, sheets, foils, nets, porous materials, foams, and nonwoven fabrics.

[0051] The metal layers 1122 and 1123 may be 0.2 μm to 5.0 μm thick, preferably 0.3 μm or more, 0.5 μm or more, or 0.6 μm or more, and may also be 3.0 μm or less, 2.0 μm or less, 1.5 μm or less, or 1.0 μm or less. When the thickness of the metal layer satisfies the above range, it can function without problems as a support, is a thickness that allows for easy control of physical properties, and is the optimal thickness considering resistance, energy density, etc.

[0052] The ratio of the thickness of the metal layer to the polymer resin layer may be 1:1 to 1:15, and the ratio of the thickness may be the ratio with either one of the two metal layers, and the thickness of the two metal layers may be applied independently of each other. The ratio of the thickness may be 1:1 to 1:15, preferably 1:4 to 1:12, and more preferably 1:6 to 1:10. When the ratio of the thickness of the first or second metal layer to the polymer resin layer satisfies the above numerical range, there is an effect of increasing the energy density of the cell while improving safety.

[0053] unwinding section In one embodiment, the electrode manufacturing apparatus 100 has an electrode current collector 112 and a process film 113 wound sequentially from the outer circumferential surface of a supply roller 111, and includes an unwinding section 110 that continuously supplies the electrode current collector 112.

[0054] Figure 2 shows the unwinding section, where the electrode current collector 112 is wound around the outer circumferential surface of the supply roller 111 and is located inside the unwinding section 110, and the process film 113 is wound from the outer circumferential surface of the electrode current collector 112 and is located outside.

[0055] By winding the electrode current collector 112 and the process film 113 together onto the supply roller 111 to form the unwinding section 110, the process film 113 wound later can be run first while process conditions are being set. This prevents problems such as wrinkles occurring during roll winding or in the middle of the process when running the electrode current collector 112, thus preventing wear and tear / disposal of the electrode current collector. Furthermore, compared to winding the process film 113 onto a separate roller and performing a run test, process inefficiencies such as interrupting the process to replace the roller can be eliminated, resulting in significant process advantages.

[0056] In the electrode manufacturing apparatus 100, the process film 113 wound around the outer part of the unwinding section 110 is made of the same polymer resin layer 1121 of the electrode current collector 112 wound around the inner part.

[0057] In the configuration of the unwinding section 110, the metal layers 1122 and 1123 are formed only on a portion of the polymer resin layer 1121, allowing the unwinding section 110 to be easily manufactured. Furthermore, when extracting optimal conditions using process conditions as variables, the accuracy of the process and the quality of the electrodes can be ensured by actually applying the same material as the polymer resin layer of the electrode current collector.

[0058] The ratio of the lengths of the electrode current collector to the process film may be 1.5:1 to 3.5:1. The length of the electrode current collector can be approximately 1.5 to 3.5 times the length of the process film, preferably 1.6 times or more, 1.7 times or more, 1.8 times or more, or 2.0 times or more, and can also be 3.4 times or less, 3.3 times or less, 3.2 times or less, 3.1 times or less, or 3.0 times or less. By doing so, process conditions that improve electrode quality with maximum accuracy can be extracted. The above range takes into account the length of the process film that is consumed and the length of the process film that needs to be run when extracting process conditions.

[0059] The process film may be at least longer than the total length of the line of the roll-to-roll process to which it is applied. Process conditions can be extracted without running the entire process, but for more accurate extraction of process conditions, it may be necessary to run a process film that is at least the length of the entire process.

[0060] The process film may be coated with a lower alcohol on its surface, or its surface may be subjected to room-temperature plasma treatment. The process film may be applied to extract process conditions in order to minimize defects before actually applying the metallized film electrode current collector to the electrode manufacturing apparatus. However, the process film is not limited to such functions; by coating with a lower alcohol or performing room-temperature plasma treatment, it can remove foreign matter present on various rollers during the roll-to-roll process, and can be subjected to a variety of functions.

[0061] Active material forming part According to one embodiment, the electrode manufacturing apparatus 200, 300 includes a roll-to-roll process and includes active material forming sections 220, 320 that form an active material layer on the surface of the electrode current collector 112.

[0062] The electrode manufacturing apparatus 200 may also employ a wet method, as shown in Figure 3, wherein the active material forming section 220 includes an active material coating section 221 for coating a slurry containing the active material onto the surface of the electrode current collector, and a drying section 222 for drying the active material coated on the electrode current collector.

[0063] In the active material forming section 220, the active material coating section 221 can apply a slurry containing electrode active material, conductive material, and binder onto the electrode current collector 112. After the active material layer is applied, the electrode can be manufactured by the drying section 222. The active material coating section 221 may form the active material layer on only one side of the electrode current collector 112, or on both sides. The electrode manufacturing apparatus shown in Figure 3 is a wet method, and in the process of applying and drying the slurry, additional guide rollers may be arranged and used as needed, in addition to the guide rollers 251, 252, and 253 shown in Figure 3.

[0064] The application method and drying method for the slurry containing the electrode active material can be any method that is common in the art, and are not limited to such methods.

[0065] Alternatively, the electrode manufacturing apparatus 300 may be a dry-type apparatus in which the active material forming section 320 includes a powdering section 321 that produces powder containing the active material and a calendering section 322 that roll-rolls the powder to produce a self-supporting film 370, as shown in Figure 4.

[0066] The dry method may be a solvent-free process in which an electrode active material, a conductive material, and a binder are mixed, then shear force is applied to form aggregates, which are then crushed and then calendered to produce a self-supporting film 370. In this case, the electrode current collector 112 can be bonded to the film by lamination. Since the dry method involves a roll-to-roll process from the pre-sheeting step of the crushed aggregate powder to the calendering step, the guide rollers 354 and 355 can be positioned in appropriate locations and in appropriate numbers.

[0067] Electrode manufacturing method According to other embodiments, an electrode manufacturing method is provided, which may be an electrode manufacturing method using the electrode manufacturing apparatus described above.

[0068] The electrode manufacturing method is characterized by including the steps of: (S1) guiding the process film in priority to the electrode current collector from an unwinding section in which an electrode current collector and a process film are sequentially wound around the outer circumference of a roller; (S2) collecting data on the degree of deformation of the process film, with process conditions including temperature as variables, while the process film is being guided; (S3) extracting process conditions in which the process film does not deform from the collected data; and (S4) guiding the electrode current collector film under the process conditions extracted in step S3 so that the active material layer is placed on the electrode current collector.

[0069] In step S2, the electrode current collector may, to the extent possible, take into account all conditions under which the polymer resin layer is affected by heat, specifically, the conditions of the heat treatment chamber during electrode drying, the temperature conditions of the heating roll, and so on.

[0070] When the above manufacturing method is applied, the optimal process conditions can be extracted in advance using the process film, thereby significantly reducing the defect rate. To extract even more optimal process conditions, in step S1, the process film may be controlled to be guided for at least the entire length of the roll-to-roll process line.

[0071] In the aforementioned manufacturing method, explanations regarding the electrode current collector and process film, and the method of arranging the active material layer on the electrode current collector, are the same as those described in the aforementioned description of the electrode manufacturing apparatus, and therefore are omitted.

[0072] Lithium-ion rechargeable battery A lithium secondary battery may include an electrode assembly impregnated with an electrolyte in a pouch-type, cylindrical, or rectangular battery case. The electrode assembly includes electrodes, and may include electrodes manufactured by an electrode manufacturing apparatus according to one embodiment of the present invention.

[0073] The electrode assembly comprises a positive electrode, a separator membrane, and a negative electrode stacked sequentially, the separator membrane being positioned between the positive electrode and the negative electrode, the positive electrode including a positive electrode current collector and a positive electrode active material layer stacked on the positive electrode current collector, and the negative electrode including a negative electrode current collector and a negative electrode active material layer stacked on the negative electrode current collector. At least one of the positive electrode and the negative electrode may be manufactured by the electrode manufacturing apparatus of the present invention as described above.

[0074] positive electrode The metal layer of the positive electrode current collector may contain a highly conductive metal and is not particularly limited as long as the positive electrode active material layer is easily adhered to it and it is unreactive within the battery voltage range. Examples of the positive electrode current collector include stainless steel, aluminum, nickel, titanium, heat-treated carbon, and aluminum or stainless steel whose surfaces have been surface-treated with carbon, nickel, titanium, silver, etc. The positive electrode current collector usually has a thickness of 3 μm to 500 μm, and fine irregularities can be formed on the surface of the current collector to enhance the adhesion strength of the positive electrode active material. For example, it can be used in various forms such as film, sheet, foil, net, porous material, foam, and nonwoven fabric.

[0075] The positive electrode active material layer may, as needed, selectively contain a conductive material and a binder together with the positive electrode active material.

[0076] Here, the positive electrode active material may be included in an amount of 80% to 99% by weight, more specifically 90% to 98% by weight, relative to the total weight of the positive electrode active material layer.

[0077] The conductive material is used to impart conductivity to the electrodes and can be used without particular limitations as long as it does not cause chemical changes in the battery and has electronic conductivity. Specific examples include graphite such as natural graphite and artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, and carbon fiber; metal powders or metal fibers such as copper, nickel, aluminum, and silver; conductive tubes such as carbon nanotubes; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive polymers such as polyphenylene derivatives. One of these can be used alone or a mixture of two or more. The conductive material may be present in an amount of 0.01% to 10% by weight, preferably 0.1% to 9% by weight, and more preferably 0.1% to 5% by weight, relative to the total weight of the positive electrode active material layer.

[0078] The binder plays a role in improving the adhesion between positive electrode active material particles and the adhesion between the positive electrode active material and the current collector. Specific examples include polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, polymethyl methacrylate, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber, polyacrylic acid, and polymers in which their hydrogen atoms are substituted with Li, Na, or Ca, or various copolymers thereof. One of these alone or a mixture of two or more can be used. The binder may be present in an amount of 1% to 30% by weight, preferably 1% to 20% by weight, and more preferably 1% to 10% by weight, relative to the total weight of the positive electrode active material layer.

[0079] The positive electrode can be manufactured by a conventional method for manufacturing a positive electrode, except that the positive electrode active material is used. Specifically, the positive electrode slurry composition, which is prepared by dissolving or dispersing the positive electrode active material, and optionally a binder, conductive material, and dispersant in a solvent, is applied to a positive electrode current collector, and then dried and rolled.

[0080] The solvent may be any solvent commonly used in the art, such as dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), dimethylformamide (DMF), acetone, or water. One of these, or a mixture of two or more, may be used. The amount of solvent used should be sufficient to dissolve or disperse the positive electrode active material, conductive material, binder, and dispersant, taking into consideration the coating thickness and production yield of the slurry, and to provide a viscosity that allows for excellent thickness uniformity during coating for the production of the positive electrode.

[0081] Alternatively, the positive electrode can also be manufactured by casting the positive electrode slurry composition onto another support, then peeling it off the support and laminating the resulting film onto the positive electrode current collector.

[0082] Separation membrane The separation membrane separates the negative electrode and the positive electrode, providing a passage for lithium ions to move. It can be used without particular limitations as long as it is a membrane typically used in lithium secondary batteries. It is particularly preferable that it has low resistance to ion movement in the electrolyte and excellent electrolyte moisture absorption capacity. Specifically, porous polymer films, such as ethylene homopolymers, propylene homopolymers, ethylene / butene copolymers, ethylene / hexene copolymers, or ethylene / methacrylate copolymers, made from polyolefin polymers, or laminated structures of two or more layers thereof, can be used. Alternatively, ordinary porous nonwoven fabrics, such as nonwoven fabrics made from high-melting-point glass fibers or polyethylene terephthalate fibers, can also be used. Furthermore, to ensure heat resistance or mechanical strength, coated separation membranes containing ceramic components or polymeric substances can be used, and they can be selectively used as single-layer or multi-layer structures.

[0083] electrolyte Examples of electrolytes include, but are not limited to, organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, and molten inorganic electrolytes that can be used in the manufacture of lithium secondary batteries.

[0084] The electrolyte may also contain an organic solvent and a lithium salt.

[0085] The organic solvent can be any solvent that serves as a medium through which ions involved in the electrochemical reaction of the battery can move, without any particular limitations. Specifically, the organic solvents include ester solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; ether solvents such as dibutyl ether and tetrahydrofuran; ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as benzene and fluorobenzene; dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), and propylene carbonate (propylene Carbonate solvents such as carbonate (PC); alcoholic solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (where R is a linear, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms, and may include a double-bonded aromatic ring or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; and sulfolanes can be used. Among these, carbonate solvents are preferred, and a mixture of a cyclic carbonate having high ionic conductivity and high dielectric constant to improve the charge and discharge performance of the battery (e.g., ethylene carbonate, propylene carbonate, etc.) and a low-viscosity linear carbonate compound (e.g., ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, etc.) is more preferred.

[0086] The lithium salt can be used without particular limitations as long as it is a compound that can provide lithium ions for use in lithium secondary batteries. Specifically, the anion of the lithium salt is 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 - may be one or more selected from the group consisting of, and the lithium salt may be LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAl04, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2, LiCl, LiI, LiB(C2O4)2, etc. The concentration of the lithium salt is preferably used within the range of 0.1M to 4.0M, more preferably 0.5M to 3.0M, and even more preferably 1.0M to 2.0M. When the concentration of the lithium salt is within the above range, the electrolyte has appropriate conductivity and viscosity, so it exhibits excellent electrolyte performance and lithium ions can move effectively.

[0087] In addition to the components of the electrolyte, the electrolyte may further contain one or more additives for the purpose of improving battery life characteristics, suppressing battery capacity reduction, and improving battery discharge capacity, such as haloalkylene carbonate compounds such as difluoroethylene carbonate, pyridine, triethyl phosphite, triethanolamine, cyclic ethers, ethylenediamine, n-glyme, hexaphosphate triamide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salts, pyrrole, 2-methoxyethanol, and aluminum trichloride. Here, the additive may be present in an amount of 0.1 to 10.0% by weight relative to the total weight of the electrolyte.

[0088] negative electrode The negative electrode includes a negative electrode current collector and a negative electrode active material layer located on the negative electrode current collector.

[0089] The metal layer of the negative electrode current collector is not particularly limited as long as it does not cause chemical changes in the battery and has high conductivity. For example, copper, stainless steel, aluminum, nickel, titanium, heat-treated carbon, copper or stainless steel with surface treatment using carbon, nickel, titanium, silver, etc., and aluminum-cadmium alloy can be used. The negative electrode current collector usually has a thickness of 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 strengthen the bonding force of the negative electrode active material. For example, it can be used in various forms such as film, sheet, foil, net, porous material, foam, and nonwoven fabric.

[0090] The negative electrode active material layer selectively includes a binder and a conductive material together with the negative electrode active material.

[0091] As the negative electrode active material, compounds capable of reversible intercalation and deintercalation of lithium can be used. Specific examples include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; metallic compounds capable of alloying with lithium, such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloys, Sn alloys, and Al alloys; and SiO2. β Examples include lithium-doped and dedoped metal oxides such as (0<β<2), SnO2, vanadium oxide, and lithium vanadium oxide; and composites containing the metallic compound and carbonaceous material, such as Si-C composites or Sn-C composites. One or more of these can be used as a mixture of two or more. A metallic lithium thin film can also be used as the negative electrode active material. Furthermore, all types of carbon materials can be used, including low-crystallinity carbon and high-crystallinity carbon. Typical examples of low-crystalline carbon include soft carbon and hard carbon, while typical examples of high-crystalline carbon include amorphous, plate-like, flaky, spherical, or fibrous natural or artificial graphite, Kish graphite, pyrolytic carbon, mesophase pitch-based carbon fiber, meso-carbon microbeads, mesophase pitches, and petroleum or coal tar pitch-derived cokes, which are high-temperature heat-treated carbons.

[0092] The negative electrode active material may be present in an amount of 80% to 99% by weight, 82% to 99% by weight, or 84% to 99% by weight, relative to the total weight of the negative electrode active material layer.

[0093] The binder is a component that assists in bonding between the conductive material, active material, and current collector, and is usually added in an amount of 0.1% to 10% by weight relative to the total weight of the negative electrode active material layer. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, nitrile-butadiene rubber, fluororubber, and various copolymers thereof.

[0094] The conductive material is a component for further improving the conductivity of the negative electrode active material, and may be included in an amount of 1% to 30% by weight, 1% to 20% by weight, or 1% to 10% by weight relative to the total weight of the negative electrode active material layer. Such a conductive material is not particularly limited as long as it does not cause a chemical change in the battery and is conductive, and for example, graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers and metal fibers; carbon fluoride; metal powders such as aluminum and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives can be used.

[0095] The negative electrode active material layer can be manufactured by coating a negative electrode slurry composition, which is prepared by dissolving or dispersing a negative electrode active material, a binder, and a conductive material selectively in a solvent, onto a negative electrode current collector and drying it, or by casting the negative electrode slurry composition onto another support, then peeling it off the support and laminating the resulting film onto the negative electrode current collector.

[0096] Furthermore, the lithium secondary battery may selectively further include a battery container for housing the electrode assembly comprising the positive electrode, separator membrane, and negative electrode, and a sealing member for sealing the battery container.

[0097] Furthermore, lithium-ion batteries exhibit excellent discharge capacity, output characteristics, and stable capacity retention, making them useful in portable devices such as mobile phones, laptops, and digital cameras, as well as in electric vehicles such as hybrid electric vehicles (HEVs).

[0098] This provides a battery module containing the lithium secondary battery as a unit cell and a battery pack containing the same.

[0099] The aforementioned battery module or battery pack can be used as a power source for one or more medium-to-large devices, including power tools; electric vehicles (EVs), hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs); and power storage systems.

[0100] Examples The following describes in detail embodiments of the present invention so that those with ordinary skill in the art to which the present invention pertains can easily implement it. However, the present invention can be realized in a variety of different forms and is not limited to the embodiments described below.

[0101] Example 1 As the unwinding section, a metal layer and an electrode current collector are formed by depositing aluminum metal to a thickness of 1 μm on both sides of polyethylene terephthalate (PET) with a thickness of 4 μm. The electrode current collector with the metal layer is wound onto a supply roller in a length of 1000 m, and the process film, which is the PET film without the metal layer, is wound onto the supply roller in a length of 500 m to form the unwinding section.

[0102] The positive electrode slurry was prepared by mixing the positive electrode active material (NCM65 1520), conductive material (Li-435), and PVDF binder (KF9700, AD-c01) in N-methylpyrrolidone in a weight ratio of 96.5:1.5:2.0.

[0103] The process was started with the discharge of the process film in the aforementioned unwinding section, and optimal conditions were extracted while changing the temperature and tension. The electrodes were then manufactured by applying the conditions extracted from the discharge of the electrode current collector.

[0104] Comparative Example 1 The unwinding section and positive electrode slurry were prepared in the same manner as in Example 1, except that the aforementioned process film was not applied and only the electrode current collector was wound onto the supply roller to form the unwinding section. The electrodes were manufactured by discharging the electrode current collector from the beginning and changing the conditions twice during manufacturing.

[0105] Experimental example: Evaluation of electrode defect rate and processability The electrode defect rate was measured for Example 1 and Comparative Example 1 described above.

[0106] [Table 1]

[0107] As shown in Table 1 above, when using an electrode manufacturing apparatus according to one embodiment of the present invention, the conditions of the roll-to-roll process can be changed using a process film, which has the advantage of significantly reducing the defect rate during electrode manufacturing. [Explanation of symbols]

[0108] 100, 200, 300 electrode manufacturing equipment 110, 210, 310 unwinding section 112 Electrode current collector 1121 Polymer resin layer 1122, 1123 Metal layer 113 Process Film 120, 220, 320 Active material forming part 130, 230, 330 winding section 140, 240, 340 rolling rollers 160 electrodes 151, 152, 153, 251, 252, 253, 351, 352, 353, 354, 355 Guide rollers

Claims

1. An electrode manufacturing apparatus that uses a roll-to-roll process, The electrode current collector and process film are wound sequentially from the outer surface of the supply roller, and there is an unwinding section that continuously supplies the electrode current collector, The electrode current collector includes an active material forming section that forms an active material layer on its surface, The electrode current collector includes a polymer resin layer and metal layers disposed on both sides of the polymer resin layer. An electrode manufacturing apparatus in which the material of the process film is the same material as the polymer resin layer of the electrode current collector.

2. The electrode manufacturing apparatus according to claim 1, wherein the ratio of the lengths of the electrode current collector to the process film is 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 length of the line for the roll-to-roll process.

4. The electrode manufacturing apparatus according to claim 1, wherein the polymer resin layer includes one or more selected from the group consisting of polyester resin, epoxy resin, phenolic resin, melamine resin, urethane resin, silicone resin, vinyl acetate resin, rubber resin, acrylic resin, and polyether urethane 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 surface of the aforementioned process film is coated with a lower alcohol, or The electrode manufacturing apparatus according to claim 1, wherein the surface of the process film is subjected to room temperature plasma treatment.

7. The electrode manufacturing apparatus according to claim 1, further comprising a winding section for winding the electrode current collector on which the active material layer is arranged into a roll shape.

8. The electrode manufacturing apparatus according to claim 1, wherein the active material forming section includes an active material coating section for coating an active material slurry onto the surface of an electrode current collector, and a drying section for drying the active material coated on the electrode current collector.

9. The electrode manufacturing apparatus according to claim 1, wherein the active material forming section includes a powdering section for producing powder containing an active material, and a calendering section for rolling the powder to produce a self-supporting film.

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

15.

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

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

13. An electrode manufacturing method including a roll-to-roll process, Step (S1) involves the process film being guided in priority to the electrode current collector from the unwinding section where the electrode current collector and the process film are sequentially wound around the outer circumference of the roller, While the process film is being guided, step (S2) is to collect data on the degree of deformation of the process film, with process conditions including temperature as variables. Step (S3) extracts process conditions in which the process film does not deform from the collected data, An electrode manufacturing method comprising the step (S4) of guiding the electrode current collector under the process conditions extracted in step (S3) so that the active material layer is placed on the electrode current collector.

14. The electrode manufacturing method according to claim 13, wherein in step (S1), the process film is guided for a length of the entire length of the roll-to-roll process line.

Images