Manufacturing equipment for electrode assemblies, method for manufacturing electrode assemblies, and electrode assemblies

Abstract

The present invention provides a manufacturing apparatus for electrode assemblies that improves stability by considering the brittle and easily fused properties of lithium metal, positioning lithium metal between separation membranes and bonding them together, while preventing the bonding from separating during high-speed operation. This application provides a roll-to-roll manufacturing apparatus for electrode assemblies that includes a sheet supply unit 100 including a first sheet supply unit for supplying a first separation membrane sheet and a second separation membrane sheet and a second sheet supply unit for supplying a lithium metal sheet; a coating unit for applying a binder to at least one of the first separation membrane sheet and the second separation membrane sheet; and a bonding unit for bonding the first separation membrane sheet and the second separation membrane sheet with the lithium metal sheet in between, wherein each of the first separation membrane sheet and the second separation membrane sheet includes an inner region corresponding to the lithium metal sheet during bonding by the bonding unit and an outer region that at least partially surrounds the outer edge of the inner region in the width direction TD, and the coating unit applies the binder to at least a portion of the outer region of the first separation membrane sheet and the outer region of the second separation membrane sheet.

Description

[Technical Field]

[0001] Cross-reference to Related Applications This application claims priority based on Korean Patent Application No. 10-2024-0038053 and Korean Patent Application No. 10-2024-0056612, which were filed with the Korean Intellectual Property Office on March 19, 2024 and April 29, 2024 respectively, and the entire contents of which are incorporated herein by reference.

[0002] The present application relates to a manufacturing equipment for manufacturing an electrode assembly, a method for manufacturing an electrode assembly, and an electrode assembly. [Background Art]

[0003] Recently, demand for mobile devices such as smartphones, tablet PCs, and wireless earphones has been increasing. In addition, as the development of electric vehicles, energy storage batteries, robots, and satellites progresses in earnest, research on high-performance secondary batteries that can be repeatedly charged and discharged as an energy source is being actively conducted.

[0004] Currently, commercialized secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Among these, lithium secondary batteries have the advantages that almost no memory effect occurs compared to nickel-based secondary batteries, charging and discharging can be performed freely, the self-discharge rate is extremely low, and the energy density is high.

[0005] On the other hand, lithium metal batteries sometimes use lithium metal as an anode. Lithium metal is advantageous for increasing the energy density of a battery, but compared to conventionally mainly used copper (Cu), it is brittle, has the property of easily burning and seizing, and is difficult to handle. [Summary of Invention] [Problem to be Solved by Invention]

[0006] This application provides electrode assembly manufacturing equipment that improves stability by positioning lithium metal between separation membranes and laminating them, taking into account the brittle and easily seized characteristics of lithium metal, while preventing the lamination from separating during high-speed operation. This application provides electrode assembly manufacturing equipment that improves productivity by preventing alignment problems even if the tension on the sheet is not maintained or if it is distorted due to meandering during high-speed operation in a roll-to-roll method. This application provides electrode assembly manufacturing equipment that prevents the lithium metal from growing in the direction of lamination, thereby minimizing short-circuit problems during battery operation. This application provides a method for manufacturing electrode assemblies using electrode assembly manufacturing equipment, and provides electrode assemblies manufactured through electrode assembly manufacturing equipment. [Means for solving the problem]

[0007] A roll-to-roll electrode assembly manufacturing apparatus according to one embodiment of this application includes a sheet supply unit including a first sheet supply unit for supplying a first separation membrane sheet and a second separation membrane sheet, and a second sheet supply unit for supplying a lithium metal sheet; an application unit for applying a binder to at least one of the first separation membrane sheet and the second separation membrane sheet; and an interlocking unit for interlocking the first separation membrane sheet and the second separation membrane sheet with the lithium metal sheet in between, wherein each of the first separation membrane sheet and the second separation membrane sheet includes an inner region corresponding to the lithium metal sheet when interlocked by the interlocking unit, and an outer region that at least partially surrounds the outer edge of the inner region in the width direction TD, and the application unit can apply the binder to at least a portion of the outer region of the first separation membrane sheet and the outer region of the second separation membrane sheet.

[0008] In a manufacturing apparatus for an electrode assembly according to one embodiment of this application, the first separation membrane sheet and the second separation membrane sheet can be joined to each other based on the adhesive strength of the applied binder.

[0009] In the electrode assembly manufacturing equipment according to one embodiment of this application, the coating portion does not need to apply the binder to the inner region of the first separation membrane sheet and the inner region of the second separation membrane sheet.

[0010] In a manufacturing apparatus for an electrode assembly according to one embodiment of the present application, the outer region of the first separation membrane sheet and the outer region of the second separation membrane sheet each include a first outer region adjacent to the first outer boundary in the width direction TD of the lithium metal sheet and a second outer region adjacent to the second outer boundary in the width direction TD of the lithium metal sheet, and the coating portion may be coated with a binder in either the first outer region of the first separation membrane sheet or the first outer region of the second separation membrane sheet, and in either the second outer region of the first separation membrane sheet or the second outer region of the second separation membrane sheet.

[0011] In a manufacturing apparatus for an electrode assembly according to one embodiment of this application, the interleaving portion interleaves the first separation membrane sheet and the second separation membrane sheet with the lithium metal sheet in between, such that one side of the lithium metal sheet faces the inner region of the first separation membrane sheet and the other side of the lithium metal sheet faces the inner region of the second separation membrane sheet, and the coating portion can continuously or partially coat the binder to at least a portion of the outer region of the first separation membrane sheet and the outer region of the second separation membrane sheet.

[0012] In a manufacturing apparatus for an electrode assembly according to one embodiment of this application, the interleaving portion may include a pair of guide rollers spaced apart at a predetermined interval.

[0013] In a manufacturing apparatus for an electrode assembly according to one embodiment of this application, the interleaving section can be configured such that, during the interleaving process, the pair of guide rollers contact the first separation membrane sheet and the second separation membrane sheet, respectively, but the lithium metal sheet does not come into contact with the lithium metal sheet, with the lithium metal sheet interposed between the first separation membrane sheet and the second separation membrane sheet during interleaving.

[0014] In a manufacturing apparatus for an electrode assembly according to one embodiment of the present application, the outer region of the first separation membrane sheet and the outer region of the second separation membrane sheet each include a first outer region adjacent to the first outer boundary in the width direction TD of the lithium metal sheet and a second outer region adjacent to the second outer boundary in the width direction TD of the lithium metal sheet, and each of the pair of guide rollers may include a first member for pressing the respective first outer regions of the first separation membrane sheet and the second separation membrane sheet; a second member for pressing the respective second outer regions of the first separation membrane sheet and the second separation membrane sheet; and a connecting member for connecting the first member and the second member.

[0015] In a manufacturing apparatus for an electrode assembly according to one embodiment of this application, the first member, the second member, and the connecting member may each have a cylindrical shape.

[0016] In the electrode assembly manufacturing equipment according to one embodiment of this application, the bottom outer diameter r3 of the connecting member may be smaller than the bottom outer diameter r1 of the first member and the bottom outer diameter r2 of the second member.

[0017] In a manufacturing apparatus for an electrode assembly according to one embodiment of this application, the first member and the second member may be arranged to rotate with respect to the same axis of rotation.

[0018] In a manufacturing apparatus for an electrode assembly according to one embodiment of this application, the center of the bottom surface of the connecting member can be located on the rotation axis of the first member and the second member.

[0019] In a manufacturing apparatus for an electrode assembly according to one embodiment of this application, the thickness w1 of the first member is less than or equal to the widthwise TD length of the first outer region OA_1 of the first separation membrane sheet and the second separation membrane sheet, and the thickness w2 of the second member may be less than or equal to the widthwise TD length of the second outer region OA_2 of the first separation membrane sheet and the second separation membrane sheet.

[0020] In a manufacturing apparatus for an electrode assembly according to one embodiment of this application, the thickness w3 of the connecting member may be the same as or greater than the widthwise TD length ML_TDw of the lithium metal sheet.

[0021] A method for manufacturing an electrode assembly according to one embodiment of this application includes the steps of: preparing a first separation membrane sheet, a second separation membrane sheet, and a lithium metal sheet in roll form; applying a binder to at least one partial area of ​​the first separation membrane sheet and the second separation membrane sheet; and laminating the first separation membrane sheet and the second separation membrane sheet with the lithium metal sheet in between to form a negative electrode structure, wherein the step of applying the binder may include applying the binder to an outer area of ​​at least one of the first separation membrane sheet and the second separation membrane sheet that at least partially surrounds the inner area corresponding to the lithium metal sheet in the width direction TD during lamination.

[0022] A method for manufacturing an electrode assembly according to one embodiment of this application may further include the steps of stacking a positive electrode on the formed negative electrode structure, folding the negative electrode structure in the width direction so as to surround the positive electrode, and alternately stacking the negative electrode structure and the positive electrode in sequence.

[0023] An electrode assembly according to one embodiment of the present application includes a positive electrode, a negative electrode, and a separator membrane, wherein the negative electrode includes lithium metal and is interposed between two separator membranes to form a negative electrode structure, the negative electrode structure includes a plurality of stack portions and a plurality of folding portions, the electrode assembly has a structure in which the stack portions of the negative electrode structure and the positive electrode are alternately stacked in sequence, the two separator membranes are formed to protrude at least partially in the width direction from the lithium metal, and at least a portion of the protruding portions of the two separator membranes can be joined to each other by sandwiching the lithium metal with a binder.

[0024] In an electrode assembly according to one embodiment of this application, the positive electrode includes a positive electrode active material layer containing a positive electrode active material and a positive electrode current collector supporting the positive electrode active material layer, wherein the positive electrode active material may contain a sulfur compound. [Effects of the Invention]

[0025] In the present application, in consideration of the characteristics of lithium metal that it is brittle and prone to occurrence of burning phenomena, lithium metal is placed between separation membranes and interleaved therewith, and stability can be improved by preventing the interleaving paper from separating during high-speed operation. In a roll-to-roll process, the present application can prevent alignment problems and improve productivity even when tension applied to a sheet is not maintained during high-speed operation or distortion occurs due to meandering. The present application can prevent dendrite growth in the direction in which lithium metal is interleaved, and manufacture an electrode assembly that minimizes the short-circuit problem during battery operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings presented in the present application are according to embodiments of the present application. The proportions of the width, height or thickness (or height) of each component are provided for detailed description of the present application, and these proportions may differ from actual proportions. Further, in the coordinate system shown in the drawings, each axis is perpendicular to each other, the direction indicated by an arrow is the positive direction, and the direction diametrically opposite to the direction indicated by the arrow (the direction rotated by 180 degrees) may be the negative direction.

[0027] [Figure 1] FIG. 1 is a plan view showing at least a part of an electrode assembly manufacturing facility according to an embodiment of the present application. [Figure 2] FIG. 2 is a plan view showing a position and a method in which a coating unit according to an embodiment of the present application coats a binder onto a separation membrane sheet. [Figure 3] FIG. 3 is a plan view showing a position and a method in which a coating unit according to an embodiment of the present application coats a binder onto a separation membrane sheet. [Figure 4] FIG. 4 is a plan view showing a position and a method in which a coating unit according to an embodiment of the present application coats a binder onto a separation membrane sheet. [Figure 5] FIG. 5 is a plan view showing a coating unit according to an embodiment of the present application and a position where the coating unit coats a binder onto a separation membrane sheet. [Figure 6] This is a perspective view showing how the separation membrane sheet and the lithium metal sheet move along the direction of travel MD in a manufacturing facility for an electrode assembly according to an embodiment of this application. [Figure 7] This is a plan view showing the positional relationship between the separation membrane sheet and the lithium metal sheet in the manufacturing equipment for the electrode assembly according to the embodiment of this application. [Figure 8] This is a plan view showing the positional relationship between the separation membrane sheet and the lithium metal sheet in the manufacturing equipment for the electrode assembly according to the embodiment of this application. [Figure 9] This is a plan view showing the positional relationship between the separation membrane sheet and the lithium metal sheet in the manufacturing equipment for the electrode assembly according to the embodiment of this application. [Figure 10] A perspective view showing at least a portion of the laminated paper portion according to the embodiment of this application. [Figure 11] This is a perspective view showing at least a portion of the guide roller according to the embodiment of this application. [Figure 12] This is a plan view showing at least a portion of the guide roller according to the embodiment of this application. [Figure 13] A perspective view showing at least a portion of the laminated paper portion according to the embodiment of this application. [Figure 14] This is a plan view showing at least a part of the negative electrode structure according to the embodiment of this application. [Figure 15] This is a plan view showing at least a portion of an electrode assembly according to an embodiment of the present application. [Modes for carrying out the invention]

[0028] Prior to the detailed description of this application, terms and words used herein and in the claims may not be construed to be limited to their ordinary or dictionary meanings. Furthermore, based on the principle that inventors may appropriately define the concepts of terms in order to best describe their invention, they may be interpreted in a sense and concept consistent with the technical idea of ​​this application. The embodiments and configurations shown in the drawings described herein are merely the most preferred embodiments of this application and do not represent all of the technical idea of ​​this application. Therefore, various equivalents and variations may exist at the time of filing of this application.

[0029] The same reference numerals or symbols in each of the drawings attached to this specification may represent parts or components that perform substantially the same function. For the sake of explanation and understanding, different embodiments may be described using the same reference numerals or symbols. That is, even if multiple drawings show a component with the same reference numeral, not all of the drawings may represent a single embodiment.

[0030] In the following description, singular expressions include plural expressions unless they have a clearly different meaning in context. Terms such as “contains” or “constitutes” are intended to specify the presence of features, figures, stages, operations, components, parts, or combinations thereof described in the specification, and should not be understood to preemptively exclude the possibility of the presence or addition of one or more other features, figures, stages, operations, components, parts, or combinations thereof.

[0031] Furthermore, in the following explanation, terms such as "top," "upper," "lower," "bottom," "side," "front," and "back" are used based on the direction shown in the drawing, and may be expressed differently if the direction of the object changes.

[0032] Furthermore, this specification and the claims may use terms containing ordinal numbers, such as "first," "second," etc., to distinguish between components. Such ordinal numbers may be used to distinguish identical or similar components from one another, and the use of such ordinal numbers should not be interpreted restrictively. For example, the order of use or arrangement of components combined with these ordinal numbers should not be interpreted restrictively by their numbers. If necessary, the ordinal numbers may be used interchangeably with each other.

[0033] In this specification, "battery" may be used interchangeably with "cell." Furthermore, "battery" or "cell" may be a general term referring to these units: a battery cell, a battery module containing a battery cell, or a battery pack.

[0034] This application considers the brittle and easily bonded properties of lithium metal and involves positioning the lithium metal between separation films during lamination, thereby improving stability by preventing separation of the lamination during high-speed operations. In a roll-to-roll system, this application prevents alignment problems and improves productivity even if the tension on the sheet is not maintained or if it becomes distorted due to meandering during high-speed operations. This application prevents the lithium metal from growing in the direction of lamination, enabling the manufacture of electrode assemblies that minimize short-circuit problems during battery operation.

[0035] Figure 1 is a plan view showing at least a part of the electrode assembly manufacturing equipment 10 according to an embodiment of this application.

[0036] The electrode assembly manufacturing equipment 10 may carry out at least some processes using a roll-to-roll method. The roll-to-roll process is a continuous process in which sheet-form material is subjected to tension using rollers to process it to acquire new functional properties. Because the roll-to-roll process processes the material continuously, it may be advantageous for mass production.

[0037] The electrode assembly manufacturing equipment 10 can manufacture the negative electrode structure 400 by positioning a lithium metal sheet ML between a plurality of separation membrane sheets 111S and 112S and passing the interleaving paper between the plurality of separation membrane sheets 111S and 112S (see Figure 14).

[0038] In this specification, a separation membrane sheet may mean a membrane in sheet form that prevents electrical short circuits between the positive electrode (cathode) and the negative electrode (anode) in a battery cell and allows electron transfer material to pass through. Here, the electron transfer material is, for example, lithium ions (Li + ), sodium ions (Na + ) or potassium ions (K + ) is possible.

[0039] The multiple separation membrane sheets 111S and 112S are not particularly limited as long as they are used in the industry, and it is desirable that they have low resistance to ion movement of the electrolyte while having excellent wettability of the electrolyte (especially the electrolyte solution). Each of the multiple separation membrane sheets 111S and 112S can be independently a porous polymer film, for example, a porous polymer film made from a polyolefin material such as an ethylene polymer, a propylene polymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, or an ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof.

[0040] The electrode assembly manufacturing equipment 10 may include a sheet supply unit 100 for supplying a plurality of separation membrane sheets (e.g., a first separation membrane sheet 111S, a second separation membrane sheet 112S), a coating unit 200 for applying binder B (see Figures 2 to 5), and a lamination unit 300 for laminating the plurality of separation membrane sheets 111S, 112S with the lithium metal sheet ML in between. Although not all are shown in the drawings, the plurality of separation membrane sheets 111S, 112S and the lithium metal sheet ML can be subjected to appropriate tension without slack by rollers R provided in appropriate locations. In one example, the sheet supply unit 100 can continuously supply the plurality of separation membrane sheets (e.g., a first separation membrane sheet 111S, a second separation membrane sheet 112S) and at least one of the lithium metal sheet ML in roll form. In this specification, continuous supply may mean that at least a portion of the area is supplied without interruption.

[0041] For the electrode assembly manufacturing equipment 10 to continuously produce negative electrode structures 400 of similar quality, it is advantageous for multiple separation membrane sheets 111S, 112S and lithium metal sheet ML to be laminated with their margin portions (e.g., outer regions in the width direction) aligned while maintaining appropriate tension. However, during high-speed operation using a roll-to-roll method, problems may occur such as changes in tension in at least some parts or misalignment due to meandering. In particular, a misalignment can be described as an alignment problem.

[0042] The electrode assembly manufacturing equipment 10 applies binder B to a portion of a plurality of separation membrane sheets 111S and 112S, and the plurality of separation membrane sheets 111S and 112S are joined together based on the adhesive strength of the applied binder B. This prevents the interleaving paper between the separation membrane sheets 111S and 112S from separating during high-speed operation, thereby preventing alignment problems and improving productivity.

[0043] In this specification, Binder B is not particularly limited in type, as long as it exhibits adhesive properties on its own or through thermal curing or photocuring, etc., without causing physical or chemical reactions with substances present in the battery cell. Binder B may include, for example, acrylic resins, urethane resins, epoxy resins, or silicone resins, which are commonly known to be used as adhesives.

[0044] The sheet supply unit 100 may include a first sheet supply unit 110 that supplies the first separation membrane sheet 111S and the second separation membrane sheet 112S. The first sheet supply unit 110 may include a 1-1 sheet supply unit 111 that supplies the first separation membrane sheet 111S and a 1-2 sheet supply unit 112 that supplies the second separation membrane sheet 112S. The first sheet supply unit 110 may supply additional separation membrane sheets in addition to the first separation membrane sheet 111S and the second separation membrane sheet 112S. In one example, the 1-1 sheet supply unit 111 may continuously supply the first separation membrane sheet 111S in roll form. In one example, the 1-2 sheet supply unit 112 may continuously supply the second separation membrane sheet 112S in roll form.

[0045] The sheet supply unit 100 may include a second sheet supply unit 120 that supplies lithium metal sheets ML. The rates at which the first sheet supply unit 110 and the second sheet supply unit 120 supply the separation membrane sheets 111S, 112S and lithium metal sheets ML can be set to be the same in order to prevent alignment problems. In one example, the second sheet supply unit 120 may continuously supply lithium metal sheets ML in roll form.

[0046] The sheet supply unit 100 is a device capable of supplying a plurality of separation membrane sheets 111S, 112S and lithium metal sheet ML at a constant rate, and may include, for example, a conveyor belt. The sheet supply unit 100 can also set a predetermined path so that the plurality of separation membrane sheets 111S, 112S and lithium metal sheet ML meet at the interleaving unit 300, which will be described later. In this specification, the direction of the path by which the sheet supply unit 100 moves each sheet can be referred to as the direction of travel MD.

[0047] The coating unit 200 can apply binder B to at least one of the first separation membrane sheet 111S and the second separation membrane sheet 112S. For example, the electrode assembly manufacturing equipment 10 may include multiple coating units 200 to apply binder B to predetermined positions.

[0048] Figures 2, 3, and 4 are plan views showing the position and method by which the coating unit 200 applies binder B onto a single separation membrane sheet 111S according to the embodiment of this application. Figure 5 is a plan view showing the coating unit 200 and the position by which the coating unit 200 applies binder B onto a single separation membrane sheet 111S according to an embodiment of this application. Details regarding the position and method of applying binder B to the other separation membrane sheets 112S can be found in the description below.

[0049] Figure 6 is a perspective view showing how the separation membrane sheets 111S, 112S and lithium metal sheet ML move along the direction of travel MD in the electrode assembly manufacturing equipment 10 according to an embodiment of this application. Figures 7, 8, and 9 are plan views showing the positional relationship between the separation membrane sheets 111S, 112S and lithium metal sheet ML in the electrode assembly manufacturing equipment 10 according to an embodiment of this application.

[0050] The coating unit 200 can apply binder B to at least one of the first separation membrane sheet 111S and the second separation membrane sheet 112S, which are moved by the sheet supply unit 100. The rate at which the sheet supply unit 100 supplies the first separation membrane sheet 111S and the second separation membrane sheet 112S can be determined by considering the viscosity of binder B and the discharge rate of binder B by the coating unit 200. The first separation membrane sheet 111S and the second separation membrane sheet 112S can be joined together based on the applied binder B, which can be done in the lamination unit 300 described later.

[0051] The structure of the coating unit 200 is not particularly limited, but may include an injection unit 210 into which binder B is injected, a storage unit 220 for storing binder B received from the injection unit 210, and a discharge unit 230 for discharging binder B stored in the storage unit 220 to the outside. The coating unit 200 may further include a pump for smooth injection and discharge of binder B, and the force exerted by the pump may cause binder B to flow smoothly from the injection unit 210 to the storage unit 220 or to be smoothly discharged to the outside through the discharge unit 230. The coating unit 200 may further include an opening / closing unit that opens and closes the space between the storage unit 220 and the discharge unit 230, and the opening / closing unit may further include an element that can be controlled by an electrical signal and can pattern the binder B to be applied to the first separation membrane sheet 111S or the second separation membrane sheet 112S.

[0052] The coating section 200 can coat binder B onto at least one of the first separation membrane sheet 111S and the second separation membrane sheet 112S. Each of the first separation membrane sheet 111S and the second separation membrane sheet 112S may include an inner region IA corresponding to the lithium metal sheet ML when laminated by the lamination section 300, and an outer region OA that at least partially surrounds the outer edge of the inner region IA in the transverse direction (TD). The transverse direction TD may be perpendicular to the direction of travel MD.

[0053] Here, the coating unit 200 may apply binder B to at least a portion of the outer region OA of the first separation membrane sheet 111S and the outer region OA of the second separation membrane sheet 112S. Alternatively, the coating unit 200 may not apply binder B to the inner region IA of the first separation membrane sheet 111S and the inner region IA of the second separation membrane sheet 112S.

[0054] The method by which the coating unit 200 applies the binder B is not particularly limited. For example, the coating unit 200 may continuously or partially apply the binder B to at least a portion of the outer region OA of the first separation membrane sheet 111S and the outer region OA of the second separation membrane sheet 112S. Referring to Figure 2, the coating unit 200 may continuously apply the binder B. Referring to Figures 3 and 4, the coating unit 200 may partially apply the binder B. The coating unit 200 may, for example, implement a method of applying the binder B through the aforementioned opening and closing section.

[0055] Each of the outer regions OA of the first separation membrane sheet 111S and the second separation membrane sheet 112S may include a first outer region OA_1 adjacent to the first outer boundary ML_O1 in the width direction of the lithium metal sheet ML and a second outer region OA_2 adjacent to the second outer boundary ML_O2 in the width direction of the lithium metal sheet ML. The first outer boundary ML_O1 in the width direction of the lithium metal sheet ML may be located on the opposite side of the second outer boundary ML_O2.

[0056] The coating unit 200 can apply binder B to at least one of the first outer region OA_1 of the first separation membrane sheet 111S and the first outer region OA_1 of the second separation membrane sheet 112S, and to at least one of the second outer region OA_2 of the first separation membrane sheet 111S and the second outer region OA_2 of the second separation membrane sheet 112S. That is, the coating unit 200 can apply binder B so that it is appropriately positioned so that the first separation membrane sheet 111S and the second separation membrane sheet 112S are joined together in the outer region OA.

[0057] For example, referring to Figure 7, the coating portion 200 can coat binder B on both the first outer region OA_1 and the second outer region OA_2 of the first separation membrane sheet 111S, or it can coat binder B only on the second outer region OA_2 of the second separation membrane sheet 112S.

[0058] Referring to Figure 8, the coating unit 200 can apply binder B to both the first outer region OA_1 and the second outer region OA_2 of the first separation membrane sheet 111S, but not to the second separation membrane sheet 112S. Alternatively, as another example, the coating unit 200 can apply binder B to both the first outer region OA_1 and the second outer region OA_2 of the second separation membrane sheet 112S, but not to the first separation membrane sheet 111S. Even if binder B is applied in this way, there is no problem in the mutual bonding of the first separation membrane sheet 111S and the second separation membrane sheet 112S based on binder B.

[0059] Furthermore, referring to Figure 9, the coating unit 200 can apply binder B only to the first outer region OA_1 of the first separation membrane sheet 111S and the second outer region OA_2 of the second separation membrane sheet 112S. Alternatively, the coating unit 200 can apply binder B only to the second outer region OA_2 of the first separation membrane sheet 111S and the first outer region OA_1 of the second separation membrane sheet 112S.

[0060] In addition, although not shown, the coating section 200 can apply binder B to all of the first outer region OA_1 and the second outer region OA_2 of the first separation membrane sheet 111S, and to all of the first outer region OA_1 and the second outer region OA_2 of the second separation membrane sheet 112S, and the application of binder B to only one of these regions can be omitted.

[0061] Figure 10 is a perspective view showing at least a portion of the interleaving section 300 according to an embodiment of this application. Figure 11 is a perspective view showing at least a portion of the guide roller 310 according to an embodiment of this application. Figure 12 is a plan view showing at least a portion of the guide roller 310 according to an embodiment of this application. Figure 13 is a perspective view showing at least a portion of the interleaving section 300 according to an embodiment of this application.

[0062] The laminating section 300 can laminate the first separation membrane sheet 111S and the second separation membrane sheet 112S with the lithium metal sheet ML in between. Specifically, the laminating section 300 can laminate the first separation membrane sheet 111S and the second separation membrane sheet 112S with the lithium metal sheet ML in between, such that one side of the lithium metal sheet ML faces the inner region IA of the first separation membrane sheet 111S and the other side of the lithium metal sheet ML faces the inner region IA of the second separation membrane sheet 112S. The laminating section 300 includes, for example, a pair of guide rollers 310 spaced apart at a predetermined interval, and the lamination can be realized using the pair of guide rollers 310.

[0063] Referring to Figure 10, the pair of guide rollers 310 can be spaced apart at a predetermined interval, such that the first separation membrane sheet 111S, the lithium metal sheet ML, and the second separation membrane sheet 112S can all pass through, while a portion of the first separation membrane sheet 111S and a portion of the second separation membrane sheet 112S can come into contact with each other due to the pressing force of the pair of guide rollers 310.

[0064] In the lamination section 300, the pair of guide rollers 310 come into contact with the first separation membrane sheet 111S and the second separation membrane sheet 112S respectively during lamination, but the lithium metal sheet ML is interposed between the first separation membrane sheet 111S and the second separation membrane sheet 112S so that the two rollers do not come into contact with the lithium metal sheet ML. At this time, the first separation membrane sheet 111S can come into contact with one side of the lithium metal sheet ML, and the second separation membrane sheet 112S can come into contact with the other side of the lithium metal sheet ML.

[0065] Each of the pair of guide rollers 310 may include a first member 311 that presses against the first outer region OA_1 of the first separation membrane sheet 111S and the second separation membrane sheet 112S, a second member 312 that presses against the second outer region OA_2 of the first separation membrane sheet 111S and the second separation membrane sheet 112S, and a connecting member 313 that connects the first member 311 and the second member 312. Since the first member 311 and the second member 312 of each of the pair of guide rollers 310 press against the first separation membrane sheet 111S and the second separation membrane sheet 112S at positions corresponding to the first outer region OA_1 and the second outer region OA_2, the first separation membrane sheet 111S and the second separation membrane sheet 112S can be joined together by the adhesive force of the binder B applied to these regions.

[0066] On the other hand, the connecting member 313 passes through positions corresponding to the inner regions IA of the first separation membrane sheet 111S and the second separation membrane sheet 112S, and may or may not press against the inner regions IA.

[0067] The first member 311, the second member 312, and the connecting member 313 can each have a cylindrical shape. The cylindrical shape includes a circular base and square sides. Only the first separation membrane sheet 111S and the second separation membrane sheet 112S pass between each of the first member 311 and the second member 312 of the pair of guide rollers 310, but the first separation membrane sheet 111S, the second separation membrane sheet 112S, and the lithium metal sheet ML can pass between the connecting members 313. Therefore, for uniform interfacing, the outer diameter r3 of the base of the connecting member 313 may be smaller than the outer diameter r1 of the base of the first member 311 and the outer diameter r2 of the base of the second member 312.

[0068] On the other hand, for uniform lamination, the bottom outer diameter r1 of the first member 311 and the bottom outer diameter r2 of the second member 312 may be the same. Also, for uniform lamination, the difference between the bottom outer diameter r1 of the first member 311, the bottom outer diameter r2 of the second member 312, and the bottom outer diameter r3 of the connecting member 313 may be the same as or greater than the widthwise length of the lithium metal sheet ML.

[0069] The first member 311 and the second member 312 may be configured to rotate around the same axis of rotation. The rotatable members can press against the outer regions OA of the first separation membrane sheet 111S and the second separation membrane sheet 112S, thereby joining them together, which can help improve production speed.

[0070] Furthermore, the center of the bottom surface of the connecting member 313 (i.e., the center of the circle) may be located on the axis of rotation of the first member 311 and the second member 312. A guide roller 310 with such a structure can be useful for uniform lamination.

[0071] When the coating portion 200 continuously coats binder B to at least a portion of the outer region OA of the first separation membrane sheet 111S and the outer region OA of the second separation membrane sheet 112S, the thickness w1 of the first member 311 may be the same as or greater than the widthwise TD length B_w1 of binder B coated on at least one of the first outer region OA_1 of the first separation membrane sheet 111S and the first outer region OA_1 of the second separation membrane sheet 112S. The thickness w2 of the second member 312 may be the same as or greater than the widthwise TD length B_w2 of binder B coated on at least one of the second outer region OA_2 of the first separation membrane sheet 111S and the second outer region OA_2 of the second separation membrane sheet 112S.

[0072] On the other hand, the thickness w1 of the first member 311 is less than or equal to the widthwise TD length of the first outer region OA_1 of the first separation membrane sheet 111S and the second separation membrane sheet 112S, and the thickness w2 of the second member 312 may be less than or equal to the widthwise TD length of the second outer region OA_2 of the first separation membrane sheet 111S and the second separation membrane sheet 112S. Here, the thickness w1 of the first member 311 and the thickness w2 of the second member 312 may each represent the height of the cylindrical shape (vertical distance between the bases).

[0073] The thickness w3 of the connecting member 313 may be the same as or greater than the widthwise TD length ML_TDw of the lithium metal sheet ML. Here, the thickness w3 of the connecting member 313 can represent the height of the cylindrical shape (vertical distance between the bases).

[0074] On the other hand, the sum of the thickness w1 of the first member 311, the thickness w2 of the second member 312, and the thickness w3 of the connecting member 313 may be equal to or greater than the widthwise TD length 111S_TDw of the first separation membrane sheet 111S. Alternatively, the widthwise TD length of the second separation membrane sheet 112S may be similar.

[0075] Figure 14 is a plan view showing at least a portion of the negative electrode structure 400 according to an embodiment of this application.

[0076] The electrode assembly manufacturing equipment 10 can manufacture a negative electrode structure 400 in which a first separation membrane sheet 111S, a second separation membrane sheet 112S, and a lithium metal sheet ML are passed through a bonding section 300, and the first separation membrane sheet 111S and the second separation membrane sheet 112S are bonded together based on a binder B, thereby forming bonding regions AA at both ends. The electrode assembly manufacturing equipment 10 may further include additional equipment to improve the bonding performance of the binder B, for example, at least one of a heating device and a drying device.

[0077] On the other hand, this application can provide a method for manufacturing an electrode assembly. The method for manufacturing an electrode assembly can refer to the contents of the electrode assembly manufacturing equipment 10 described above, unless otherwise contradictory.

[0078] A method for manufacturing an electrode assembly may include the step of preparing a first separation membrane sheet 111S, a second separation membrane sheet 112S, and a lithium metal sheet ML in roll form. This step can be implemented by the sheet supply unit 100 of the electrode assembly manufacturing equipment 10.

[0079] A method for manufacturing an electrode assembly may include the step of applying binder B to at least one portion of the prepared first separation membrane sheet 111S and second separation membrane sheet 112S. This step may be embodied in the coating section 200 of the electrode assembly manufacturing equipment 10.

[0080] A method for manufacturing an electrode assembly may include the step of forming a negative electrode structure 400 by laminating a first separation membrane sheet 111S and a second separation membrane sheet 112S with a lithium metal sheet ML in between. This step can be implemented in the lamination section 300 of the electrode assembly manufacturing equipment 10.

[0081] In a method for manufacturing an electrode assembly, the step of applying binder B may include applying binder B to an outer region OA in at least one of the first separation membrane sheet 111S and the second separation membrane sheet 112S that at least partially surrounds the inner region IA corresponding to the lithium metal sheet ML in the width direction TD during lamination.

[0082] The method for manufacturing an electrode assembly may further include the steps of stacking a positive electrode 500 on a formed negative electrode structure 400, folding the negative electrode structure 400 in the width direction TD so as to surround the positive electrode 500, and alternately stacking the negative electrode structure 400 and the positive electrode 500 in sequence.

[0083] The positive electrode 500 may include a positive electrode active material layer and a positive electrode current collector supporting the positive electrode active material layer. The positive electrode 500 may include a structure in which the positive electrode active material layer is formed on at least one or both sides of the positive electrode current collector. The positive electrode active material layer includes a positive electrode active material and may further include a binder, conductive material, and additives as needed.

[0084] The positive electrode current collector is not particularly limited as long as it supports the positive electrode active material layer without undergoing physical and chemical changes to the components contained in the electrode assembly 50 and the battery cell, etc., and is conductive. For example, aluminum, stainless steel, nickel, titanium, copper, palladium, calcined carbon, carbon, nickel or silver, or copper or stainless steel, or aluminum-cadmium alloy can be used as the positive electrode current collector. Furthermore, the positive electrode current collector may have fine irregularities formed on its surface, and its form can vary, such as film, sheet, foil, mesh, net, or foam.

[0085] The positive electrode active material may include compounds capable of reversibly intercalating and deintercalating lithium ions, sodium ions, or potassium ions. For example, lithium, sodium, or potassium compounds used as positive electrode active materials may have a layered structure, a crystalline structure, or a combination thereof. Furthermore, the lithium compound as used herein may be a concept that encompasses all forms of compounds in which auxiliary elements, coating elements, and doping elements are introduced or substituted around a main active element. The main active element may include, for example, one or more selected from the group consisting of nickel (Ni), cobalt (Co), manganese (Mn), and aluminum (Al). Auxiliary elements, coating elements, and doping elements are elements that can be combined with the main active element to improve the structural and chemical stability of the positive electrode active material, and can be distinguished by the manner in which they are combined with the main active element. Here, being combined with the main active element naturally includes not only chemical bonding with the main active element, but also elements that are present on the surface of the positive electrode active material or that penetrate from the surface. Furthermore, for example, auxiliary elements, coating elements, and doping elements may each independently include one or more elements selected from the group consisting of Group 1, Group 2, Group 13, Group 14, Group 15, Group 16 elements and transition metals on the periodic table, excluding lithium. Specifically, for example, the auxiliary elements, coating elements, and doping elements may each independently include one or more selected from the group consisting of sodium (Na), magnesium (Mg), calcium (Ca), yttrium (Y), titanium (Ti), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), iron (Fe), copper (Cu), silver (Ag), zinc (Zn), boron (B), gallium (Ga), carbon (C), silicon (Si), tin (Sn), strontium (Sr), barium (Ba), radium (Ra), phosphorus (P), and zirconium (Zr).For example, the positive electrode active material may include one or more selected from the group consisting of nickel-cobalt-manganese oxide (NCM), nickel-cobalt-aluminum oxide (NCA), nickel-cobalt-manganese-aluminum oxide (NCMA), cobalt oxide (LCO), manganese oxide (LMO), and iron phosphate (LFP) bonded with lithium, sodium, or potassium.

[0086] On the other hand, the positive electrode active material may contain sulfur compounds. These sulfur compounds include inorganic sulfur (Elemental sulfur, S8) and organic sulfur compounds (Li2S). x (x is 1 or greater) and carbon-sulfur polymer ((C2S y ) n It may include one or more selected from the group consisting of y = 2.5 to 50, where n is 1 or greater. Preferably, the sulfur compound may include inorganic sulfur. When the positive electrode active material contains a sulfur compound, the electrode assembly 50 can be applied to a lithium-sulfur battery.

[0087] The binder may contain compounds that improve the internal bonding force of the positive electrode active material layer and improve the adhesion of the positive electrode active material layer to the positive electrode current collector. Examples of binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, styrene butadiene rubber (SBR), polyethylene oxide, carboxyl methyl cellulose (CMC), cellulose acetate, cellulose acetate butylate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, and cyanoethyl sucrose. It may contain one or more selected from the group consisting of sucrose, pullulan, polymethyl methacrylate, polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, and polyarylate.

[0088] The conductive material may include compounds that can improve the conductivity and ion or electron mobility of the positive electrode active material layer. The conductive material may include, for example, carbon-based conductive materials such as graphite, carbon black, acetylene black, Ketjenblack, graphene, carbon nanotubes (CNTs), VGCF (vapor-grown carbon fiber), and carbon fibers, and / or metallic conductive materials such as tin, tin oxide, titanium oxide, perovskite materials such as LaSrCoO3 and LaSrMnO3. The carbon nanotubes (CNTs) may include one or more selected from the group consisting of multi-walled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs) depending on the number of walls.

[0089] Figure 15 is a plan view showing at least a portion of an electrode assembly 50 according to one embodiment of the present application. The electrode assembly 50 may include a positive electrode 500, a negative electrode, and a separator membrane. On the other hand, the electrode assembly manufacturing equipment 10 may further include a positive electrode supply device, and the electrode assembly 50 can be manufactured by combining the positive electrode 500 and the negative electrode structure 400 supplied from the positive electrode supply device. Here, the negative electrode structure 400 includes lithium metal, and the lithium metal may be interposed between two separator membranes. The two separator membranes may also be formed to protrude at least partially in the width direction TD from the lithium metal, and at least a portion of the protruding portions of the two separator membranes may be joined together with a binder B sandwiching the lithium metal. This can be embodied in the electrode assembly manufacturing equipment 10 described above. In other words, the two separation membranes can be manufactured from a first separation membrane sheet 111S and a second separation membrane sheet 112S, and the protruding portions of the two separation membranes can correspond to the outer regions OA of the first separation membrane sheet 111S and the second separation membrane sheet 112S.

[0090] Furthermore, the electrode assembly 50 can be manufactured, for example, by zigzag-folding a negative electrode structure 400 manufactured in a long sheet form, and then inserting a positive electrode 500 cut to an appropriate size into the space formed by the bending. Even if the negative electrode structure 400 contains a lithium metal sheet ML, it can be made into a bent form due to its brittle properties. On the other hand, the positive electrode 500 is not as easy to fold as the negative electrode structure 400, and is easier to cut, so as mentioned above, it can be cut to an appropriate size for use.

[0091] The negative electrode structure 400 may include a stack portion that forms a stacked structure with the inserted positive electrode 500 and a folded portion that is folded as described above. The electrode assembly 50 may have a structure in which the stack portion of the negative electrode structure 400 and the positive electrode 500 are alternately stacked in sequence.

[0092] The electrode assembly 50 manufactured in the electrode assembly manufacturing equipment 10 can be housed in a case along with the electrolyte to manufacture a battery cell. Furthermore, the battery cell can be used to manufacture a battery module, battery pack, or energy storage device.

[0093] The electrode assembly manufacturing equipment 10 can be widely applied to green technology fields such as electric vehicles, battery charging stations, and solar and wind power generation using batteries. Furthermore, the electrode assembly manufacturing equipment 10 can be applied to environmentally friendly electric vehicles or hybrid vehicles that suppress air pollution and greenhouse gas emissions and prevent climate change.

[0094] Although various embodiments of this application have been described in detail above, the scope of rights of this application is not limited thereto, and it will be obvious to anyone with average knowledge of the art that various modifications and variations are possible without departing from the technical idea of ​​this application as described in the claims. Furthermore, some components may be omitted from the embodiments described above, and each embodiment may be implemented in combination with one another. [Explanation of Symbols]

[0095] 10. Manufacturing equipment for electrode assemblies 50...electrode assembly 100-Sheet Supply Unit 110...First Sheet Supply Unit 111...1st-1st Sheet Supply Unit 111S...First separation membrane sheet 112...1st-2nd Sheet Supply Section 112S...Second separation membrane sheet 120...Second Sheet Supply Unit ML...Lithium Metal Sheet 200...Coated area 210...Injection part 220...Storage section 230...Discharge part 300...Interleaf part 310... Guide roller 311...First component 312...Second component 313...Third component 400...Negative electrode structure 500...Positive electrode

Claims

1. A sheet supply unit including a first sheet supply unit that supplies a first separation membrane sheet and a second separation membrane sheet, and a second sheet supply unit that supplies a lithium metal sheet, A coating section for applying a binder to at least one of the first separation membrane sheet and the second separation membrane sheet, It includes a laminating section that laminates the first separation membrane sheet and the second separation membrane sheet with the lithium metal sheet in between, Each of the first separation membrane sheet and the second separation membrane sheet includes an inner region corresponding to the lithium metal sheet when laminated by the laminating portion, and an outer region that at least partially surrounds the outer edge of the inner region in the width direction TD. The coating unit is a roll-to-roll electrode assembly manufacturing facility that applies the binder to at least a portion of the outer region of the first separation membrane sheet and the outer region of the second separation membrane sheet.

2. The manufacturing apparatus for an electrode assembly according to claim 1, wherein the first separation membrane sheet and the second separation membrane sheet are joined together based on the adhesive strength of the applied binder.

3. The manufacturing equipment for an electrode assembly according to claim 1, wherein the coating portion does not coat the binder in the inner region of the first separation membrane sheet and the inner region of the second separation membrane sheet.

4. Each of the outer regions of the first separation membrane sheet and the second separation membrane sheet includes a first outer region adjacent to the first outer boundary in the width direction TD of the lithium metal sheet and a second outer region adjacent to the second outer boundary in the width direction TD of the lithium metal sheet, The coating portion is The first outer region of the first separation membrane sheet and the first outer region of the second separation membrane sheet, The electrode assembly manufacturing apparatus according to claim 1, wherein the binder is applied to either the second outer region of the first separation membrane sheet or the second outer region of the second separation membrane sheet.

5. The laminated portion is formed by laminating the first separation membrane sheet and the second separation membrane sheet with the lithium metal sheet in between, such that one side of the lithium metal sheet faces the inner region of the first separation membrane sheet and the other side of the lithium metal sheet faces the inner region of the second separation membrane sheet. The manufacturing apparatus for an electrode assembly according to claim 1, wherein the coating portion continuously or partially coats the binder to at least a portion of the outer region of the first separation membrane sheet and the outer region of the second separation membrane sheet.

6. The electrode assembly manufacturing apparatus according to claim 1, wherein the interleaving section includes a pair of guide rollers spaced apart at a predetermined interval.

7. The aforementioned interleaving section, when interleaving, Manufacturing equipment for an electrode assembly according to claim 6, wherein the pair of guide rollers contact the first separation membrane sheet and the second separation membrane sheet, respectively, but do not contact the lithium metal sheet, by interposing the lithium metal sheet between the first separation membrane sheet and the second separation membrane sheet and bonding them together.

8. Each of the outer regions of the first separation membrane sheet and the second separation membrane sheet includes a first outer region adjacent to the first outer boundary in the width direction TD of the lithium metal sheet and a second outer region adjacent to the second outer boundary in the width direction TD of the lithium metal sheet, Each of the pair of guide rollers is A first member that presses the first outer region of each of the first and second separation membrane sheets, A second member that presses the second outer region of each of the first and second separation membrane sheets, Manufacturing equipment for an electrode assembly according to claim 6, comprising a connecting member for connecting the first member and the second member.

9. The outer diameter r of the bottom surface of the connecting member ３ The outer diameter r of the bottom surface of the first member is １ and the bottom outer diameter r of the second member ２ A smaller manufacturing apparatus for the electrode assembly described in claim 8.

10. The thickness w of the first member １ The manufacturing equipment for an electrode assembly according to claim 8, wherein the width direction TD length of the first outer region OA_1 of the first separation membrane sheet and the second separation membrane sheet is less than or equal to the width direction TD length of the second member w2 is less than or equal to the width direction TD length of the second outer region OA_2 of the first separation membrane sheet and the second separation membrane sheet.

11. The thickness w of the connecting member ３ The manufacturing equipment for the electrode assembly according to claim 8, wherein the widthwise TD length ML_TDw of the lithium metal sheet is the same as or greater than the TD length ML_TDw of the lithium metal sheet.

12. A method for manufacturing an electrode assembly, The steps include preparing a first separation membrane sheet, a second separation membrane sheet, and a lithium metal sheet in roll form, The steps include applying a binder to at least one partial area of ​​the first separation membrane sheet and the second separation membrane sheet, The step includes forming a negative electrode structure by laminating the first separation membrane sheet and the second separation membrane sheet with the lithium metal sheet in between, The step of applying the aforementioned binder is: A method for manufacturing an electrode assembly, comprising the step of applying the binder to an outer region of at least one of the first separation membrane sheet and the second separation membrane sheet that at least partially surrounds the inner region corresponding to the lithium metal sheet in the width direction TD when the sheets are laminated.

13. A method for manufacturing an electrode assembly according to claim 12, further comprising the steps of stacking a positive electrode on the formed negative electrode structure, folding the negative electrode structure in the width direction so as to surround the positive electrode, and alternately stacking the negative electrode structure and the positive electrode in sequence.

14. An electrode assembly comprising a positive electrode, a negative electrode, and a separator membrane, The negative electrode contains lithium metal and is interposed between two separation membranes to form a negative electrode structure. The negative electrode structure includes a plurality of stacking sections and a plurality of folding sections, The electrode assembly has a structure in which the stack portion of the negative electrode structure and the positive electrode are stacked alternately in sequence. The two separation membranes are formed to protrude at least partially in the width direction from the lithium metal, An electrode assembly in which at least a portion of the protruding portions of the two separation membranes are joined together with a binder sandwiching the lithium metal.

15. The positive electrode includes a positive electrode active material layer containing a positive electrode active material and a positive electrode current collector supporting the positive electrode active material layer. The electrode assembly according to claim 14, wherein the positive electrode active material contains a sulfur compound.

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