Rolled electrode body

Abstract

The present application provides a rolled electrode body, a manufacturing method thereof, and a process using the rolled electrode body (a manufacturing method for a secondary battery). The present application can provide a rolled electrode body that can reduce losses generated in existing processes and contribute to improving yield and productivity, a manufacturing method thereof, and a manufacturing method for a secondary battery using the same.

Description

[Technical Field]

[0001] Cross-Citation of Related Applications This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0139078 filed on October 19, 2021, and Korean Patent Application No. 10-2022-0134010 filed on October 18, 2022, and all contents disclosed in the documents of the relevant Korean patent applications are incorporated herein by reference.

[0002] The present application relates to a rolled electrode assembly, a method for manufacturing the same, and processes utilizing the same. [Background technology]

[0003] The application of energy storage technology is expanding to include not only mobile devices, video cameras, and laptops, but also automobiles. One of the research areas for energy storage technology is rechargeable secondary batteries.

[0004] An electrode assembly used in a secondary battery basically has a structure in which a positive electrode and a negative electrode, each having a laminated structure of a current collector and an active material layer, are stacked with a separator sandwiched therebetween.

[0005] Such a secondary battery manufacturing process, particularly a so-called roll-to-roll manufacturing process, can be carried out while unwinding an electrode wound in a roll shape.

[0006] 1 shows a process for manufacturing a rolled electrode that can be applied to the above process. As shown in Fig. 1, an electrode 100 is wound into a roll, and to maintain the wound shape, a certain portion 1001 of the electrode is fixed with adhesive or bonding tape 200. An additional double-sided tape 300 is also attached, which is attached for the purpose of connecting to other rolls during the process.

[0007] 2 shows a state in which the rolled electrode assembly shown in FIG. 1 is unwound and connected to another element 400 via double-sided tape 300 for the process to proceed. As shown in FIG. 2, when the rolled electrode assembly of FIG. 1 is unwound, traces 2001 of the tape 200 that was attached to secure the roll are left behind. Since the portion with traces 2001 cannot be used, the section indicated by the dotted arrow in FIG. 2 is discarded (discard section D), and therefore only the portion that is wound at least once is lost. Summary of the Invention [Problem to be solved by the invention]

[0008] This application relates to a rolled electrode body, a method for manufacturing the same, and a process using the rolled electrode body (a method for manufacturing a secondary battery). The purpose of this application is to provide a rolled electrode body, a method for manufacturing the same, and a method for manufacturing a secondary battery using the same that can reduce losses that occur in existing processes and contribute to improving yield and productivity. [Means for solving the problem]

[0009] The present application relates to a rolled electrode assembly.

[0010] The rolled electrode body can include an electrode wound into a roll; and a polymer film or sheet wound around the outside of the electrode wound into a roll.

[0011] The electrode of the roll-shaped electrode body may include a current collector and an electrode active material layer formed on at least one surface of the current collector.

[0012] The rolled electrode body may further include a double-sided adhesive tape or tape that attaches the rolled electrode and the polymer film or sheet, and the double-sided adhesive tape or tape may be attached to at least one end of the electrode.

[0013] The roll-shaped electrode body may further include an adhesive or sticky tape attached to the polymer film or sheet to maintain the polymer film or sheet in a rolled state. The tape may be attached to at least one end and any other portion of the polymer film or sheet, or to one end and the other end of the polymer film or sheet. That is, when the ends of the polymer film or sheet are in contact after being rolled, the tape adheres to one end and the other end of the film or sheet, thereby maintaining the rolled state. Furthermore, when the ends of the polymer film or sheet are not in contact after being rolled, but one end is rolled beyond the other end, the tape adheres to one end and any other portion of the film or sheet, thereby maintaining the rolled state.

[0014] The rolled electrode assembly may include an additional double-sided adhesive or tape attached to the polymer film or sheet, and such tape may be attached to the surface of the polymer film or sheet opposite to the surface facing the rolled electrode.

[0015] The present application also relates to a method for manufacturing a rolled electrode assembly, including the steps of attaching an electrode to a polymer film or sheet, winding the electrode into a roll, and winding the rolled electrode with the polymer film or sheet. The order in which the steps of the method are performed is not particularly limited as long as the desired rolled electrode assembly is manufactured. For example, the electrode may first be wound into a roll and then the polymer film or sheet may be attached, or the winding step may be performed after the attachment.

[0016] The electrodes and the polymer film or sheet may be attached using double-sided adhesive or adhesive tape.

[0017] The manufacturing method may further include a step of fixing the rolled polymer film or sheet around the electrode with an adhesive tape.

[0018] The method for manufacturing the rolled electrode assembly may further include the step of attaching a double-sided adhesive or tape to the polymer film or sheet, The double-sided adhesive or tape may be attached to the surface of the polymer film or sheet opposite to the surface facing the rolled electrode.

[0019] The present application also relates to a method for manufacturing a secondary battery using the rolled electrode body, and the method may include applying the rolled electrode to a process while unwinding the electrode.

[0020] In the above, when the roll-shaped electrode body includes a double-sided adhesive or adhesive tape that adheres the electrode and the polymer film or sheet, the method may further include a step of removing the portion of the electrode to which the double-sided adhesive or adhesive tape is attached.

[0021] In addition, the method may further include a step of connecting the electrode to another element by using a double-sided adhesive or tape attached to the polymer film or sheet, and the double-sided adhesive or tape may be attached to the surface of the polymer film or sheet opposite to the surface facing the rolled electrode.

[0022] The method for manufacturing the secondary battery may be carried out by a so-called roll-to-roll process. [Effects of the Invention]

[0023] The present application provides a rolled electrode body, a method for manufacturing the same, and a process using the rolled electrode body (a method for manufacturing a secondary battery).The present application can provide a rolled electrode body, a method for manufacturing the same, and a method for manufacturing a secondary battery using the same that can reduce losses that occur in existing processes and contribute to improving yield and productivity. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a diagram illustrating a rolled electrode body according to a conventional technique. [Figure 2] 1 is a diagram illustrating a rolled electrode body according to a conventional technique. [Figure 3] 1 is a diagram illustrating an example of an electrode assembly of the present application. [Figure 4] 1 is a diagram illustrating one end and the other end of an electrode, a polymer film, or the like. [Figure 5] 1 is a diagram exemplarily illustrating a process for manufacturing an electrode assembly according to the present application. [Figure 6] 1 is a diagram exemplarily illustrating a process for manufacturing an electrode assembly according to the present application. [Figure 7] 1 is a diagram illustrating an example of an electrode body according to the present application applied to a process. DETAILED DESCRIPTION OF THE INVENTION

[0025] As used herein, the term "electrode assembly" may refer to a product including an electrode and a polymer film or sheet, as described below, or a product in which two or more electrodes are directly connected, or in which the two or more electrodes are connected via the polymer film or sheet.

[0026] FIG. 3 is a conceptual diagram showing a rolled electrode body of the present application.

[0027] As shown in FIG. 3, the rolled electrode body may include an electrode 100 wound in a roll; and a polymer film or sheet (hereinafter, may be referred to as a polymer film, etc.) 500 wound around the outside of the electrode 100 wound in a roll.

[0028] The rolled electrode body may further include a double-sided adhesive or adhesive tape 301 for attaching the rolled electrode 100 and the polymer film 500 .

[0029] The double-sided adhesive or adhesive tape 301 may be attached to the surface of one end of the electrode 100 and the inner surface of the polymer film 500 .

[0030] As used herein, one end of an electrode or polymer film, for example, refers to the region from one end (E1) of the electrode or polymer film, etc. 5000 to 0.4 times the overall length (L) of the electrode or polymer film, etc. (the region from E1 to 0.4L in FIG. 4), or 0.3 times the length (0.3L) (the region from E1 to 0.3L in FIG. 4), or 0.2 times the length (0.2L) (the region from E1 to 0.2L in FIG. 4), or 0.1 times the length (0.1L) (the region from E1 to 0.1L in FIG. 4), as shown in FIG. 4. FIG. 4 is a side view of the electrode or polymer film, etc. 5000.

[0031] Furthermore, when referring to both one end and the other end of an electrode, polymer film, etc., in this specification, the one end refers to one end of the electrode, polymer film, etc., and the other end refers to the other end opposite the one end. For example, referring to Figure 4, the region from E1 to 0.4 L, the region from E1 to 0.3 L, the region from E1 to 0.2 L, or the region from E1 to 0.1 L in Figure 4 is the one end, and the region from E2 to 0.4 L, the region from E2 to 0.3 L, the region from E2 to 0.2 L, or the region from E2 to 0.1 L in Figure 4 is the other end.

[0032] In this specification, the inner surface of the polymer film, etc., may be the surface of the polymer film, etc. 500 facing the electrode 100, as shown in FIG. 3, and the outer surface may be the surface of the polymer film, etc. 500 opposite to the surface facing the electrode 100.

[0033] The rolled electrode body may further include an adhesive or sticky tape 200 attached to the surface of at least one end of the rolled polymer film 500 to fix the rolled shape.

[0034] The adhesive or adhesive tape 200 may be attached to the outer surface of the polymeric film or the like 500 .

[0035] The adhesive or sticky tape 200 may adhere to the outer surfaces of both ends of the wound polymer film or sheet 500 to secure the wound configuration, or may adhere to the outer surface of one end of the polymer film or sheet 500 and the outer surface of any other portion of the polymer film or sheet 500 to secure the wound configuration. That is, when the two ends of the polymer film or sheet 500 are in contact with each other in the wound state (as shown in FIG. 3), the tape adheres to the outer surfaces of one end and the other end of the film or sheet to secure the wound configuration. Also, when the two ends of the polymer film or sheet are not in contact after the polymer film or sheet is wound, and one end is wound beyond the other end, the tape adheres to the outer surface of one end of the film or sheet and the outer surface of any other portion of the film or sheet to secure the wound configuration. The tape 200 that secures the wound configuration does not need to be a double-sided adhesive or sticky tape; it may be a single-sided adhesive or sticky tape.

[0036] As described above, the adhesive or sticky tape 200 adheres to the outer surface of the polymer film 500, but does not adhere to the electrode 100. In this manner, the tape 200 does not leave any trace on the electrode.

[0037] The rolled electrode may include an additional double-sided adhesive or sticky tape 302 attached on the polymer film 500. The adhesive or sticky tape 302 may be formed on the surface of the rolled electrode opposite to the surface of the polymer film 500 facing the rolled electrode 100 (i.e., the outer surface). The tape 302 may be used to connect the rolled electrode to another roll during processing, or to connect the rolled electrode to another component. The additional double-sided adhesive or sticky tape 302 is attached to the outer surface of the polymer film 500, but not to the electrode 100. This configuration prevents the tape 302 from leaving a mark on the electrode.

[0038] The electrode 100 may be a cathode or cathode used in a secondary battery, for example, and may include at least a current collector and an electrode active material layer formed on one or both sides of the current collector.

[0039] 5 and 6 are diagrams showing a process for manufacturing a rolled electrode assembly having the same structure as that shown in Fig. 3. However, the following process is merely an example for manufacturing the rolled electrode assembly of the present application, and other appropriate methods for manufacturing the rolled electrode assembly of the present application may be applied in addition to the following process.

[0040] 5, to manufacture the roll-shaped electrode assembly, first, an end of the electrode 100 is attached to an end of the polymer sheet or film 500. At this time, the attachment method is not particularly limited, and for example, the attachment can be performed using a double-sided adhesive or adhesive tape 301.

[0041] Next, the electrode 100 is wound into a roll as shown in Fig. 6. Then, the polymer sheet or film 500 is wound around the wound electrode 100 to manufacture a rolled electrode assembly as shown in Fig. 3.

[0042] As shown in FIG. 3, the rolled form of the rolled polymer sheet or film 500 can be secured with adhesive or bonding tape 200 to secure the roll form if necessary.

[0043] In the process of manufacturing the electrode assembly, if necessary, a step of forming a double-sided adhesive or sticky tape 302 on the polymer film or sheet 500 can be additionally performed. Such adhesive or sticky tape 302 can be attached to the side of the polymer film or sheet 500 in the rolled electrode assembly opposite to the side facing the rolled electrode 100.

[0044] FIG. 7 shows one example of a process in which a roll-shaped electrode assembly, such as that shown in FIG. 3, is unwound and connected to another element 400 (e.g., another electrode) via double-sided adhesive or sticky tape 302. When the electrode assembly of the present application is applied as shown in the drawing, even when the rolled electrode 100 is unwound, traces 2001 of the sticky or sticky tape 200 attached to maintain the roll shape are not formed on the electrode 100 but are formed on the polymer film or sheet 500. Therefore, in such cases, only the portion of the electrode 100 where the double-sided tape 301 is present for connecting it to the polymer film or sheet 500 (disposal section D indicated by the dotted arrow in the drawing) needs to be discarded. Therefore, when the electrode assembly of the present application is applied, waste generated during the process is significantly reduced compared to conventional processes, allowing for secondary battery manufacturing processes to be carried out with superior yield and productivity.

[0045] The present application also relates to an electrode assembly formed in the process of unwinding a rolled electrode assembly as described above, and particularly to an electrode assembly in which the other element (400 in FIG. 7) is an electrode.

[0046] Such an electrode assembly may include a first electrode 100; a polymer film or the like 500; and a second electrode 400, as shown in FIG.

[0047] In the above, the first electrode 100 and the polymer film 500 may be connected by a double-sided adhesive or adhesive tape 301 (hereinafter referred to as a first adhesive or adhesive tape), and the second electrode 400 and the polymer film 500 may be connected by a double-sided adhesive or adhesive tape 302 (hereinafter referred to as a second adhesive or adhesive tape).

[0048] In this case, the first double-sided adhesive or adhesive tape 301 may be attached to the surface of one end of the first electrode 100 and the inner surface of one end of the polymer film 500 .

[0049] The second double-sided adhesive or bonding tape 302 may be attached to the surface of one end of the second electrode 400 and the outer surface of the other end of the polymer film 500 .

[0050] The structure applied to the rolled electrode body of the present application is not particularly limited, and known materials can be appropriately adopted.

[0051] For example, the current collector, which is a component of the electrode, may be a known current collector, such as a film, sheet, or foil made of stainless steel, aluminum, nickel, titanium, calcined carbon, copper, stainless steel surface-treated with carbon, nickel, titanium, or silver, or an aluminum-cadmium alloy, etc. The current collector may be subjected to known treatments such as surface treatment.

[0052] The thickness and shape of such a current collector are not particularly limited, and an appropriate type may be selected within known ranges.

[0053] There is no particular limitation on the type of the electrode active material layer formed on one or both surfaces of the current collector, and a layer containing at least an electrode active material and a binder made of a known material can be used. As the binder, a known substance can be used, and a component known to contribute to the binding of components such as the active material in the active material layer and the binding of the active material layer and the current collector can be used. Examples of applicable binders include PVDF (Poly(vinylidene fluoride), polyvinylidene chloride), PVA (poly(vinyl alcohol), polyvinyl alcohol), polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, SBR (Styrene-Butadiene rubber, styrene butadiene rubber), fluorine rubber, and one or a combination of two or more selected from other known binders can be used.

[0054] The electrode active material contained in the active material layer can be a positive electrode active material or a negative electrode active material, and the specific type is not particularly limited. For example, as the positive electrode active material, LiCoO2, LiNiO2, LiMn2O4, LiCoPO4, LiFePO4, LiNiMnCoO2, and LiNi 1-x-y-z Co x M1 y M2 z O2 (M1 and M2 are each independently selected from the group consisting of Al, Ni, Co, Fe, Mn, V, Cr, Ti, W, Ta, Mg, and Mo, and x, y, and z are each independently the atomic fraction of the oxide composition element, satisfying 0≦x<0.5, 0≦y<0.5, 0≦z<0.5, 0<x + y + z≦1), etc. can be used as the active material, and as the negative electrode active material, natural graphite, artificial graphite, carbonaceous materials; lithium-containing titanium composite oxides (LTO), Si, Sn, Li, Zn, Mg, Cd, Ce, Ni or Fe metals (Me); alloys composed of the metals (Me); oxides (MeOx) of the metals (Me); and composites of the metals (Me) and carbon, etc. can be used as the active material.

[0055] For example, the active material in the active material layer may be in a range of 1,000 to 10,000 parts by weight relative to 100 parts by weight of the binder. Other examples of the ratio may be 1,500 parts by weight or more, 2,000 parts by weight or more, 2,500 parts by weight or more, 3,000 parts by weight or more, 3,500 parts by weight or more, 4,000 parts by weight or more, or 4,500 parts by weight or more, or 9,500 parts by weight or less, 9,000 parts by weight or less, 8,500 parts by weight or less, 8,000 parts by weight or less, 7,500 parts by weight or less, 7,000 parts by weight or less, 6,500 parts by weight or less, 6,000 parts by weight or less, 5,500 parts by weight or less, 5,000 parts by weight or less, 4,500 parts by weight or less, 4,000 parts by weight or less, 3,500 parts by weight or less, 3,000 parts by weight or less, or 2,500 parts by weight or less.

[0056] The active material layer may further contain other necessary components in addition to the above components. For example, the active material layer may further contain a conductive material. The conductive material may be any known material that exhibits conductivity without inducing chemical changes in the current collector and electrode active material. For example, the conductive material may be one or a mixture of two or more selected from the following: graphite, such as natural graphite or artificial graphite; carbon black, such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers, such as carbon fiber and metal fiber; metal powders, such as carbon fluoride, aluminum, and nickel powder; conductive whiskers, such as zinc oxide and potassium titanate; and conductive metal oxides, such as titanium oxide, and polyphenylene derivatives.

[0057] The content of the conductive material is controlled as needed and is not particularly limited, but may be contained in an appropriate ratio within the range of 0.1 to 20 parts by weight or 0.3 to 12 parts by weight per 100 parts by weight of the active material. Methods for determining the content of the conductive material at an appropriate level taking into account the cycle life of the battery, etc., are well known.

[0058] The active material layer may contain other known necessary ingredients in addition to the above ingredients (for example, thickeners such as carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, or regenerated cellulose).

[0059] The thickness of the active material layer is not particularly limited, and can be controlled to an appropriate level in consideration of the desired performance.

[0060] For example, the thickness of the active material layer may be in the range of about 10 to 500 μm. In other examples, the thickness may be about 30 μm or more, 50 μm or more, 70 μm or more, 90 μm or more, or 100 μm or more, or about 450 μm or less, 400 μm or less, 350 μm or less, 300 μm or less, 250 μm or less, 200 μm or less, or 150 μm or less.

[0061] The active material layer may be formed to have a certain level of porosity. The porosity is typically controlled by rolling during the electrode manufacturing process. The active material layer may have a porosity of approximately 35% or less. The porosity may be further adjusted within the range of 33% or less, 31% or less, 29% or less, or 27% or less, and / or within the range of 5% or more, 7% or more, 9% or more, 11% or more, 13% or more, 15% or more, 17% or more, 19% or more, 21% or more, 23% or more, or 25% or more.

[0062] The electrode can be manufactured by, for example, coating a current collector with a slurry containing the active material, etc., followed by drying and rolling processes, etc. The slurry can include a solvent along with the active material, a binder, etc.

[0063] The method for applying the slurry onto the surface of the current collector is not particularly limited, and known application methods such as spin coating, comma coating, and bar coating can be used.

[0064] The polymer film or sheet applied to the rolled electrode body is not particularly limited and may be a known polymer film or sheet, for example, a polycarbonate film or sheet, a polyester film such as a PET (poly(ethylene terephthalate)) film or sheet, a polyolefin film or sheet such as a polyethylene or polypropylene film or sheet, or an acrylic polymer film or sheet such as a PMMA (poly(methylmethacrylate)) film or sheet.

[0065] There is no particular limitation on the thickness of such a film or sheet.

[0066] In addition, as the double-sided or single-sided adhesive or pressure-sensitive adhesive tape to be applied, any suitable adhesive or pressure-sensitive adhesive tape known in the related field may be selected and used. [Explanation of symbols]

[0067] 100: Electrode 1001: Adhesive or adhesive tape attachment site 200, 300, 301, 302: adhesive or adhesive tape 2001: Adhesive or adhesive tape residue 400: Other elements 500: Polymer film or sheet 5000: Electrode, polymer film or polymer sheet D: Discarded part

Claims

1. An electrode wound in a roll; a polymer film or sheet wound around the outside of the electrode wound into a roll; a single-sided adhesive or single-sided adhesive tape attached to the polymer film or sheet to maintain the polymer film or sheet in a rolled state; an additional double-sided adhesive or double-sided adhesive tape attached to the surface of the polymer film or sheet opposite to the surface facing the rolled electrode; Including, the single-sided adhesive or single-sided adhesive tape is attached to the outer surface of the polymer film or sheet and is not attached to the electrode; The electrode is connected to other elements via the additional double-sided adhesive or double-sided adhesive tape. Rolled electrode body.

2. The rolled electrode assembly according to claim 1 , wherein the electrode comprises a current collector and an electrode active material layer formed on at least one surface of the current collector.

3. 3. The rolled electrode assembly according to claim 1, further comprising a double-sided adhesive tape or a double-sided adhesive tape that adheres the electrode wound into a roll and the polymer film or sheet.

4. 4. The rolled electrode assembly according to claim 3, wherein the double-sided adhesive tape or double-sided adhesive tape adheres the surface of one end of the electrode to the inner surface of the polymer film or sheet.

5. A rolled electrode body as described in claim 1 or 2, wherein the additional double-sided adhesive or double-sided adhesive tape is attached to the outer surface of the polymer film or sheet.

6. The rolled electrode assembly according to claim 5 , wherein the additional double-sided adhesive or double-sided adhesive tape attached to the outer surface of the polymer film or sheet is not attached to the electrode.

7. attaching an electrode and a polymer film or sheet; winding the electrode into a roll; winding the rolled electrode with the polymer film or sheet; fixing the rolled polymer film or sheet with the electrode by a single-sided adhesive or adhesive tape; Including, the single-sided adhesive or sticky tape is attached to the outer surface of the polymeric film or sheet and is not attached to the electrode; The rolled electrode assembly further includes an additional double-sided adhesive or double-sided adhesive tape attached to a surface of the polymer film or sheet opposite to a surface facing the rolled electrode, and the method for manufacturing a rolled electrode assembly further includes connecting the electrode to another element via the additional double-sided adhesive or double-sided adhesive tape.

8. The method for producing a rolled electrode assembly according to claim 7 , wherein the electrodes and the polymer film or sheet are attached using a double-sided adhesive or a double-sided adhesive tape.

9. a first electrode, a polymer film or sheet, a second electrode, and a single-sided adhesive or bonding tape; The first electrode and the polymer film or sheet are connected by a first double-sided adhesive or adhesive tape attached to a surface of one end of the first electrode and an inner surface of one end of the polymer film or sheet, the polymer film or sheet is wound around the outside of the first electrode which is wound in a roll shape; The second electrode and the polymer film or sheet are connected by a double-sided adhesive or adhesive tape attached to a surface of one end of the second electrode and an outer surface of the other end of the polymer film or sheet; The single-sided adhesive or bonding tape is attached to the outer surface of the polymer film or sheet, but is not attached to the first electrode, and maintains the polymer film or sheet in a rolled-up state.

10. A method for manufacturing a secondary battery using the rolled electrode body according to claim 1, comprising: A method for manufacturing a secondary battery, comprising the step of unwinding an electrode wound in a roll and applying the electrode to a process.

11. The rolled electrode body further includes a double-sided adhesive or double-sided adhesive tape that adheres the electrode and the polymer film or sheet, The method of claim 10 , further comprising removing the electrode portion to which the double-sided adhesive tape or double-sided adhesive tape is attached.

12. The method for manufacturing a secondary battery according to claim 10 or 11, wherein the method for manufacturing the secondary battery is a roll-to-roll process.

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