Jelly roll electrode assembly and secondary battery including the same

Abstract

According to one embodiment of the present invention, there is provided a jelly roll electrode assembly in which a positive electrode sheet, a negative electrode sheet, and a separator interposed between the positive electrode sheet and the negative electrode sheet are wound together, the jelly roll electrode assembly has a plain portion wound around the outermost corner of the jelly roll electrode assembly, where an active material layer is not formed on the negative electrode sheet, and a swelling tape is attached to an inner surface of the plain portion of the negative electrode sheet toward a center of the jelly roll electrode assembly, and the swelling tape has one or more irregularities or wrinkles formed thereon.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0163387 filed on November 24, 2021 and Korean Patent Application No. 10-2022-0158763 filed on November 23, 2022, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a jelly roll electrode assembly and a secondary battery including the same. [Background technology]

[0003] With technological development and increasing demand for mobile devices, the demand for secondary batteries as an energy source is rapidly increasing. In particular, secondary batteries are attracting much attention as an energy source for mobile devices such as mobile phones, digital cameras, laptops, and wearable devices, as well as for power devices such as electric bicycles, electric cars, and hybrid electric cars.

[0004] Secondary batteries are classified according to the shape of the battery case into cylindrical batteries in which the electrode assembly is housed in a cylindrical metal can, prismatic batteries in which the electrode assembly is housed in a prismatic metal can, and pouch batteries in which the electrode assembly is housed in a pouch-shaped case made of an aluminum laminate sheet. Of these, cylindrical batteries have the advantages of being relatively large in capacity and structurally stable.

[0005] The electrode assembly built into the battery case is a chargeable / dischargeable power generating element having a laminated structure of a positive electrode, a separator, and a negative electrode, and is classified into a jelly roll type, a stack type, and a stack / folding type. The jelly roll type is a long sheet-like positive electrode and a negative electrode coated with an active material, which are wound with a separator interposed between them, the stack type is a type in which a number of positive electrodes and a negative electrodes of a predetermined size are stacked in sequence with a separator interposed between them, and the stack / folding type is a composite structure of the jelly roll type and the stack type. Among them, the jelly roll type electrode assembly has the advantages of being easy to manufacture and having a high energy density per weight.

[0006] For this reason, as the need for batteries with high capacity and high output has increased recently, in the case of cylindrical batteries, optimization is underway by changing the thickness of the current collector and separator, as well as the size and shape of the can and top cap, in order to fit a large number of electrodes into a limited space.

[0007] One method proposed is to use copper as an outer tab for the negative electrode current collector, which means that the outer tab and separator are removed and the copper current collector physically contacts the cylindrical can to pass the current.

[0008] This method reduces the amount of separator and tab used, and the outer diameter is slightly reduced, resulting in space savings and cost reduction, and the saved space can be used to increase capacity and improve output.In addition, since the copper current collector is in direct contact with the can, the area for heat transfer increases, improving the heat generation level.

[0009] However, if copper is actually exposed on the outer shell, one or two points with a large outer diameter will come into contact with the can depending on the roundness of the jelly roll, resulting in less effectiveness than previously expected.

[0010] To solve this problem, a swelling tape that expands in response to electrolyte was used to improve the contact level, but air traps were generated during attachment in the manufacturing process, which increased the outer diameter and reduced productivity.

[0011] Therefore, there is a need to develop a jelly roll electrode assembly and secondary battery technology that can solve these problems. Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention provides a jelly roll electrode assembly and a secondary battery that can improve the contact level of a negative electrode uncoated portion at the outermost corner with a battery case while eliminating a problem of an increase in outer diameter due to air trapping by uniformly controlling air trapping caused by attachment of a swelling tape.

[0013] The problems to be solved by the present invention are not limited to the problems described above, and problems not mentioned will be clearly understood by a person having ordinary skill in the art to which the present invention pertains from this specification and the accompanying drawings. [Means for solving the problem]

[0014] A jelly roll electrode assembly according to an embodiment of the present invention is a jelly roll electrode assembly in which a positive electrode sheet, a negative electrode sheet, and a separator interposed between the positive electrode sheet and the negative electrode sheet are wound together, a blank portion on which an active material layer is not formed on the negative electrode sheet is wound around an outermost corner of the jelly roll electrode assembly; A swelling tape is attached to the inner surface of the uncoated portion of the negative electrode sheet toward the center of the jelly roll electrode assembly. The swelling tape is characterized in that one or more irregularities or wrinkles are formed on the tape.

[0015] The swelling tape may be attached from a part of the inner surface of the uncoated portion of the negative electrode sheet and a boundary surface between the uncoated portion of the negative electrode sheet and a holding portion on which the active material layer is formed, in the direction of the holding portion of the negative electrode sheet to a part of the holding portion of the negative electrode sheet.

[0016] Alternatively, the swelling tape may be formed only on a part of the inner surface of the uncoated portion of the negative electrode sheet.

[0017] The swelling tape may be formed so as to cover 10% to 90% of the entire area of ​​the inner surface of the uncoated portion of the negative electrode sheet.

[0018] Furthermore, the uncoated portion of the negative electrode sheet at the outermost corner where the swelling tape is formed may face the holding portion of the negative electrode sheet located on the inner side.

[0019] Meanwhile, unevenness or wrinkles corresponding to the swelling tape are formed on the uncoated portion of the negative electrode sheet that comes into contact with the swelling tape.

[0020] The unevenness or wrinkles formed in the plain portion of the negative electrode sheet may be the unevenness or wrinkles of the swelling tape transferred thereto.

[0021] Air may be trapped in the unevenness or wrinkles of the swelling tape.

[0022] Here, the air may be trapped between the swelling tape and the uncoated portion of the negative electrode sheet.

[0023] The irregularities may have a regular pattern, specifically, the roughness (Ra) of the irregularities may be 0.1 mm to 20 mm, the size may be 10 μm to 5 mm, and when two or more irregularities are formed, the interval between them may be 50 μm to 5 mm.

[0024] In contrast, the wrinkles may be formed irregularly.

[0025] Meanwhile, according to another embodiment of the present invention, A method for manufacturing a jelly roll electrode assembly, comprising: a step of manufacturing an electrode assembly, in which a positive electrode sheet, a negative electrode sheet, and a separator are interposed between the positive electrode sheet and the negative electrode sheet, and a blank portion of the negative electrode sheet on which no active material layer is formed is wound at the outermost corner to manufacture a jelly roll electrode assembly; and The method for manufacturing a jelly roll electrode assembly includes a tape attachment step of attaching a swelling tape having an uneven surface on an inner surface toward a center of the jelly roll electrode assembly to the uncoated portion of the negative electrode sheet, or attaching the swelling tape so that wrinkles are formed on the inner surface of the uncoated portion of the negative electrode sheet toward a center of the jelly roll electrode assembly.

[0026] In this case, the swelling tape may be attached so as to form wrinkles by attaching the swelling tape in a state where a portion of the swelling tape is left unattached, by applying vibration to the attached portion to induce microbubbles or microwrinkles, or by raising the center of the suction pad to which the swelling tape is attached to form a vacuum space, thereby inducing the generation of bubbles when the swelling tape is attached.

[0027] Alternatively, according to yet another embodiment of the present invention, A method for manufacturing a jelly roll electrode assembly, comprising: A tape attachment step of attaching a swelling tape having an uneven surface or forming wrinkles on a plain portion of one end of the negative electrode sheet; and

[0028] a positive electrode sheet, a negative electrode sheet, and a separator interposed between the positive electrode sheet and the negative electrode sheet are wound up so that the portion to which the swelling tape is attached is located on an inner surface from an outermost corner of the jelly roll electrode assembly toward a center of the jelly roll electrode assembly, and a non-coated portion of the negative electrode sheet is wound up around the outermost corner to manufacture a jelly roll electrode assembly.

[0029] In this case, the swelling tape may be attached so as to form wrinkles by attaching the swelling tape in a state where a portion of the swelling tape is left unattached, by applying vibration to the attached portion to induce microbubbles or microwrinkles, or by raising the center of the suction pad to which the swelling tape is attached to form a vacuum space, thereby inducing the generation of bubbles when the swelling tape is attached.

[0030] Meanwhile, the present invention further provides a secondary battery including the jelly roll electrode assembly. [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 is a perspective view of a jelly roll electrode assembly according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a top view of a negative electrode sheet of a jelly roll electrode assembly according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a cross-sectional view of a jelly roll electrode assembly before winding according to an embodiment of the present invention. [Figure 4] FIG. 11 is a cross-sectional view of a jelly roll electrode assembly before winding according to another embodiment of the present invention. [Diagram 5] 2 is a cross-sectional view taken along line AA' in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in which: FIG. 1 is a block diagram of a semiconductor device according to an embodiment of the present invention;

[0033] In order to clearly explain the present invention, parts that are not necessary for the explanation will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0034] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, thicknesses are enlarged to clearly express various layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0035] In addition, throughout the specification, when a part "comprises" a certain element, this means that it can further include other elements, not excluding other elements, unless otherwise specified to the contrary.

[0036] In addition, throughout the specification, when we refer to "on a plane," this means when the subject part is viewed from above, and when we refer to "on a cross section," this means when the subject part is cut vertically and viewed from the side.

[0037] FIG. 1 is a perspective view of a jellyroll electrode assembly according to one embodiment of the present invention.

[0038] Referring to FIG. 1, a jelly roll electrode assembly 100 according to an embodiment of the present invention has a shape in which a positive electrode sheet, a negative electrode sheet, and a separator interposed between the positive electrode sheet and the negative electrode sheet are rolled up together.

[0039] At this time, a positive electrode tab 113 is formed on the positive electrode sheet, which can later be electrically connected to a cap assembly of a cylindrical battery to form a positive electrode terminal.

[0040] Meanwhile, a blank portion 121 where no active material layer is formed on the negative electrode sheet is wound at the outermost corner of the jelly roll electrode assembly 100, and this blank portion 121 will later come into contact with the inner wall surface of the can of the secondary battery. Therefore, the blank portion 121 of the negative electrode sheet serves as a terminal and can be electrically connected directly to the can of the cylindrical secondary battery case, eliminating the need for a separate negative electrode tab.

[0041] In addition, since the jelly roll electrode assembly 100 does not have a separator formed at the outermost corner, the outer diameter can be reduced, thereby ensuring the internal space of the battery, increasing the capacity, improving the energy density, and improving the battery performance.

[0042] However, as described above, when the uncoated portion 121 of the negative electrode sheet is actually exposed to the outer corners, one or two points with a large outer diameter come into contact with the can depending on the roundness of the jelly roll, resulting in a problem that the effect is less than previously expected. In order to solve this problem, the present invention applies a swelling tape that has the property of expanding in response to an electrolyte.

[0043] In this case, the swelling tape is attached to the inner surface toward the center of the jelly roll electrode assembly 100, not to the outer corners of the uncoated portion 121 of the negative electrode sheet of the jelly roll electrode assembly 100, so that the capacity is not affected and the uncoated portion 121 of the negative electrode sheet at the outermost corner can later come into contact with the cylindrical secondary battery case as a whole.

[0044] Therefore, no such swelling tape is shown in FIG.

[0045] Meanwhile, to specifically explain the swelling tape according to the present invention, FIG. 2 shows a top view of the negative electrode sheet 120 of the jelly roll electrode assembly 100 of FIG. 1 before winding, FIG. 3 shows a cross-sectional view of the jelly roll electrode assembly 100 of FIG. 1 before winding, FIG. 4 shows a cross-sectional view of the jelly roll electrode assembly 100 according to another embodiment before winding, and FIG. 5 shows a cross-sectional view along A-A' of the jelly roll electrode assembly 100 of FIG. 1.

[0046] First, referring to FIG. 2 and FIG. 3, the positive electrode sheet 110 includes a holding portion where a positive electrode active material layer is formed and a plain portion where a positive electrode active material layer is not formed, and the plain portion is provided between the holding portions, and a positive electrode tab 113 is attached to the plain portion.

[0047] In addition, a separator 130 is interposed between the positive electrode sheet 110 and the negative electrode sheet 120 .

[0048] The negative electrode sheet 120 includes a holding portion (negative electrode sheet holding portion 122) in which an active material layer 123 is formed on a negative electrode current collector 124, and a plain portion 121 in which the active material layer 123 is not formed. In this case, the plain portion 121 is located on one side and wound at the outermost corner to serve as a negative electrode terminal.

[0049] On the other hand, a swelling tape 125 is attached to the inner winding surface of the non-coated portion 121.

[0050] Here, the swelling tape 125 is formed on an area A′ that covers 10% to 90% of the entire area A of the inner surface of the uncoated portion 121 of the negative electrode sheet 120 .

[0051] In addition, the swelling tape 125 may be formed only on a part of the inner surface of the uncoated portion 121 so as not to overlap with the holding portion 122 of the negative electrode sheet 120 .

[0052] 4, the swelling tape 125' may be attached to a part of the inner surface of the uncoated portion 121' of the negative electrode sheet 120' and to a part of the holding portion 122' of the negative electrode sheet 120' from the interface between the uncoated portion 121' and the holding portion 122' of the negative electrode sheet 120' toward the holding portion 122' of the negative electrode sheet 120'. In this case, the swelling tape 125' is formed within a length l that does not overlap with the active material layer of the facing positive electrode sheet 110.

[0053] In either case, however, the uncoated portion 121 of the negative electrode sheet 120 at the outermost corner where the swelling tape 125 is formed faces the active material layer 123 of the negative electrode sheet 120 located on the inside, that is, the supporting portion 122.

[0054] Therefore, since the swelling tape 125 is formed on the portion of the active material layer 123 that does not face the positive electrode, i.e., the portion that does not contribute to the capacity, no capacity problem occurs. At the same time, since the swelling tape 125 is formed on the inside of the current collector 124 of the negative electrode sheet 120 from the outermost corner of the jelly roll electrode assembly 100, the current collector 124 can later come into contact with the can of the cylindrical battery case as a whole, and the intended effect of the present application can be achieved without deteriorating the improvement of the electrical conductivity and heat generation level.

[0055] Meanwhile, the swelling tape 125 has a property of expanding in volume when it absorbs an electrolyte, and may be a single-sided or double-sided tape.

[0056] At this time, the single-sided or double-sided tape is made of at least one material selected from the group consisting of polyurethane (PU), polyethylene (PE), polycarbonate (PC), polypropylene (PP), and polyimide (PI).

[0057] Alternatively, the swelling tape 125 may have a structure in which an adhesive layer is formed on one or both sides of a raw substrate.

[0058] Here, the raw substrate may be a polyolefin-based substrate, for example, polyethylene (PE) or polypropylene (PP), and the adhesive layer may include one or more materials selected from the group consisting of polyacrylate (PA), rubber, and styrene.

[0059] On the other hand, such a swelling tape 125 has one or more irregularities or wrinkles 126 formed thereon.

[0060] The unevenness or wrinkles 126 are caused by the swelling tape 125 which is placed in the right position to release the air. 127、127' Since the swelling tape 125 is formed so as to be able to trap air, the unevenness or wrinkles 126 of the swelling tape 125 127、127'Specifically, it is formed between the swelling tape 125 and the current collector 124.

[0061] Therefore, when the swelling tape 125 is attached by the air trapped in the unevenness or wrinkles 126 , unevenness or wrinkles corresponding to the swelling tape 125 are also formed in the plain portion 121 of the negative electrode sheet 120 .

[0062] In other words, referring again to FIG. 1, it can be seen that the unevenness or wrinkles 128 are transferred to the uncoated portion 121 of the negative electrode sheet.

[0063] Therefore, by artificially controlling air trapping that may occur when the swelling tape 125 is attached to the uncoated portion 121, it is possible to prevent an increase in the irregular outer diameter that would otherwise occur, and by generating unevenness or wrinkles on the surface of the uncoated portion 121 of the negative electrode sheet, it is possible to increase the area over which the uncoated portion 121 will later come into contact with the inner surface of the battery case, thereby increasing conductivity and improving resistance.

[0064] On the other hand, the unevenness or wrinkles 126 can be formed artificially.

[0065] Specifically, the projections and recesses can be formed with a regular pattern by using a rolling roll having a regular pattern.

[0066] In this case, the average roughness (Ra) of the center line of the irregularities may be 0.1 mm to 20 mm, and more specifically, 1 mm to 3 mm.

[0067] The roughness (Ra) of the unevenness means the height of the unevenness, and is the height from the flat surface to the highest point of the protrusion.

[0068] This allows the height of the unevenness to be adjusted when the unevenness is formed on the swelling tape.

[0069] If the roughness is too small and out of the above range, air may not be adequately trapped or the unevenness may not be adequately transferred to the uncoated portion of the negative electrode sheet, whereas if the roughness is too large, the overall volume may become too large, which is undesirable.

[0070] The size (W) of the irregularities may be 10 μm to 5 mm, specifically 100 μm to 2 mm.

[0071] The size means the diameter when the shape of the projections and recesses is circular, and means the longest straight line distance when the shape is polygonal.

[0072] If the size of the unevenness is too small outside the above range, the outward pushing force is insufficient and the intended surface adhesion effect of the present invention cannot be fully achieved, whereas if the size is too large, the overall volume may become large, which is undesirable.

[0073] Moreover, two or more projections and recesses may be formed, and in this case, the distance (D) between them may be 50 μm to 5 mm, specifically 100 μm to 2 mm.

[0074] If the spacing is too small and outside of this range, the air inside the projections and recesses may mix together and change the shape, which may cause the resistance variation to change. If the spacing is too large, the intended resistance reduction effect may be reduced, which is undesirable.

[0075] Meanwhile, the swelling tape 125 may have wrinkles having irregularities, rather than a regular pattern of unevenness.

[0076] Here, irregularity means that the pattern is not formed with a fixed size, height, or interval, but is formed without any regularity, even if it is intentionally formed during attachment or manufacturing of the swelling tape 125.

[0077] Nevertheless, such wrinkles can be controlled by artificially providing a space in which air can be trapped, and the trapped air can also cause wrinkles in the uncoated portion of the negative electrode sheet, thereby increasing the contact area between the uncoated portion of the negative electrode sheet at the outermost corner and the battery case.

[0078] A method for forming such irregularities and wrinkles will be described in more detail below.

[0079] According to another embodiment of the present invention, there is also provided A method for manufacturing a jelly roll electrode assembly, comprising: a step of manufacturing an electrode assembly, in which a positive electrode sheet, a negative electrode sheet, and a separator are interposed between the positive electrode sheet and the negative electrode sheet, and a blank portion of the negative electrode sheet on which no active material layer is formed is wound at the outermost corner to manufacture a jelly roll electrode assembly; and The method for manufacturing a jelly roll electrode assembly includes a tape attachment step of attaching a swelling tape having unevenness on an inner surface toward a center of the jelly roll electrode assembly to the uncoated portion of the negative electrode sheet, or attaching the swelling tape so that wrinkles are formed.

[0080] Alternatively, a method for manufacturing a jelly roll electrode assembly, comprising the steps of: A tape attachment step of attaching a swelling tape having an uneven surface or forming wrinkles on a plain portion of one end of the negative electrode sheet; and a positive electrode sheet, a negative electrode sheet, and a separator interposed between the positive electrode sheet and the negative electrode sheet, so that the portion to which the swelling tape is attached is located on an inner surface from an outermost corner of the jelly roll electrode assembly toward a center of the jelly roll electrode assembly, and a non-coated portion of the negative electrode sheet is wound around the outermost corner to manufacture a jelly roll electrode assembly.

[0081] In other words, the electrode assembly can be manufactured first, and the swelling tape can be attached to the uncoated portion of the negative electrode sheet while it is being wound up, or the electrode assembly can be manufactured by attaching the swelling tape to the uncoated portion of the negative electrode sheet before the electrode assembly is manufactured, and then winding up the negative electrode sheet and other components.

[0082] In either case, when forming unevenness on the swelling tape, for example, unevenness is formed during the manufacturing of the swelling tape using a roller having unevenness formed thereon, but this is not limited thereto, and the swelling tape having the unevenness already formed thereon is attached to the plain portion of the negative electrode sheet to manufacture the swelling tape.

[0083] Meanwhile, wrinkles can be formed in the swelling tape in various ways.

[0084] Specifically, the swelling tape may be attached so as to form wrinkles by attaching the swelling tape in a state where a portion of the swelling tape is left unattached, by applying vibration to the attached portion to induce fine bubbles or fine wrinkles, or by raising the center of the suction pad to which the swelling tape is attached to form a vacuum space, thereby inducing the generation of bubbles when the swelling tape is attached.

[0085] More specifically, when the swelling tape is attached, if a portion of the swelling tape is left unattached and then the swelling tape is attached to the uncoated portion of the negative electrode sheet using a roller, wrinkles may occur in the unattached portion.

[0086] Alternatively, when vibration is applied to the attachment portion, the attachment portion vibrates and air is inserted, and the swelling tape is attached in this state, generating fine air bubbles and creating fine wrinkles.

[0087] Alternatively, when the swelling tape is attached to the uncoated portion of the negative electrode sheet, an adsorption pad is used for attachment. In this case, the center of the adsorption pad is raised to form a vacuum space, which induces air bubbles to be generated in the center during attachment, thereby forming wrinkles due to the air bubbles.

[0088] There are various methods for forming the unevenness or wrinkles on the swelling tape, and the unevenness or wrinkles can be formed by the above-mentioned simple method, although the method is not limited thereto.

[0089] Meanwhile, according to the present invention, the trapping of air can be controlled by this method, and the contact area between the uncoated portion of the negative electrode sheet and the battery case can be increased by the trapped air formed in the swelling tape.

[0090] In addition, the composition and structure of the positive electrode sheet, the negative electrode sheet, and the separator that constitute the jelly roll electrode assembly are known in the art, so detailed description thereof will be omitted in this specification.

[0091] Meanwhile, the present invention provides a secondary battery including the jelly roll electrode assembly.

[0092] In this case, the secondary battery may be a cylindrical secondary battery in which the jelly roll electrode assembly is housed in a can or a prismatic secondary battery.

[0093] Such secondary batteries are also known in the art and will not be described in detail herein.

[0094] Although the preferred embodiment of the present invention has been described in detail above with reference to the drawings, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0095] 100: Jelly roll electrode assembly 110: Positive electrode sheet 120: Negative electrode sheet 130: Separation membrane 113: Positive electrode tab 121: Uncoated part of negative electrode sheet 122: Negative electrode sheet holding portion 125: Swelling tape 126: Bumps or wrinkles [Industrial Applicability]

[0096] According to the embodiment, the jelly roll electrode assembly of the present invention includes a swelling tape on the inner surface of the battery uncoated portion of the negative electrode sheet at the outermost corner, and unevenness or wrinkles are intentionally formed on the swelling tape to uniformly control air trapping. By utilizing this, the contact area between the negative electrode uncoated portion located at the outermost corner and the subsequent battery case can be increased, thereby ensuring conductivity and improving resistance.

Claims

1. A jelly roll electrode assembly in which a positive electrode sheet, a negative electrode sheet, and a separator interposed between the positive electrode sheet and the negative electrode sheet are wound together, a blank portion on which an active material layer is not formed on the negative electrode sheet is wound around an outermost corner of the jelly roll electrode assembly; A swelling tape is attached to the inner surface of the uncoated portion of the negative electrode sheet toward the center of the jelly roll electrode assembly. The swelling tape has one or more irregularities or wrinkles formed thereon, Air is trapped in the unevenness or wrinkles of the swelling tape. Jellyroll electrode assembly.

2. 2. The jelly roll electrode assembly according to claim 1, wherein the swelling tape is attached from a part of an inner surface of the uncoated portion of the negative electrode sheet and a boundary surface between the uncoated portion of the negative electrode sheet and a holding portion on which the active material layer is formed, to a part of the holding portion of the negative electrode sheet in a direction toward the holding portion of the negative electrode sheet.

3. 2. The jelly roll electrode assembly of claim 1, wherein the swelling tape is formed only on a portion of the inner surface of the uncoated portion of the negative electrode sheet.

4. 2. The jelly roll electrode assembly of claim 1, wherein the swelling tape is formed to cover 10% to 90% of the entire area of ​​the inner surface of the uncoated portion of the negative electrode sheet.

5. The jelly roll electrode assembly according to any one of claims 1 to 4, wherein the uncoated portion of the negative electrode sheet at the outermost corner where the swelling tape is formed faces the holding portion of the negative electrode sheet located on the inside.

6. 2. The jelly roll electrode assembly of claim 1, wherein the uncoated portion of the negative electrode sheet that comes into contact with the swelling tape has unevenness or wrinkles corresponding to the swelling tape.

7. 7. The jelly roll electrode assembly of claim 6, wherein the unevenness or the wrinkles formed in the plain portion of the negative electrode sheet are transferred by the unevenness or the wrinkles of the swelling tape.

8. 10. The jelly roll electrode assembly of claim 1, wherein the asperities have a regular pattern.

9. 9. The jelly roll electrode assembly of claim 8, wherein the roughness (Ra) of the unevenness is 0.1 mm to 20 mm.

10. The jelly roll electrode assembly of claim 8, wherein the size of the projections and recesses is 10 μm to 5 mm.

11. 9. The jelly roll electrode assembly of claim 8, wherein the projections and recesses are formed in two or more positions, and the intervals between the projections and recesses are between 50 μm and 5 mm.

12. 2. The jelly roll electrode assembly of claim 1, wherein the wrinkles are formed irregularly.

13. A method for manufacturing a jelly roll electrode assembly, comprising: The jelly roll electrode assembly is the jelly roll electrode assembly of claim 1 , a step of manufacturing an electrode assembly, which comprises winding a positive electrode sheet, a negative electrode sheet, and a separator between the positive electrode sheet and the negative electrode sheet, and winding a blank portion of the negative electrode sheet on which no active material layer is formed at the outermost corner to manufacture a jelly roll electrode assembly; and a swelling tape having an uneven surface on an inner surface of the negative electrode sheet toward a center of the negative electrode sheet, or a swelling tape having wrinkles on the inner surface of the negative electrode sheet.

14. 14. The method of claim 13, wherein the attachment of the swelling tape to form wrinkles is performed by: attaching the swelling tape in a state where a portion of the swelling tape is left unattached; vibrating the attached portion to induce microbubbles or microwrinkles; or raising a center of a suction pad to which the swelling tape is attached to form a vacuum space to induce the generation of bubbles when the swelling tape is attached.

15. A method for manufacturing a jelly roll electrode assembly, comprising: The jelly roll electrode assembly is the jelly roll electrode assembly of claim 1 , A tape attachment step of attaching a swelling tape having an uneven surface or forming wrinkles on a plain portion of one end of the negative electrode sheet; and a positive electrode sheet, a negative electrode sheet, and a separator interposed between the positive electrode sheet and the negative electrode sheet, so that the portion to which the swelling tape is attached is located on an inner surface from an outermost corner of the jelly roll electrode assembly toward a center of the jelly roll electrode assembly, and a non-coated portion of the negative electrode sheet is wound up at the outermost corner to manufacture a jelly roll electrode assembly.

16. 16. The method of claim 15, wherein the attachment of the swelling tape to form wrinkles is performed by: attaching the swelling tape in a state where a portion of the swelling tape is left unattached; vibrating the attached portion to induce microbubbles or microwrinkles; or raising a center of a suction pad to which the swelling tape is attached to form a vacuum space to induce the generation of bubbles when the swelling tape is attached.

17. A secondary battery comprising the jelly roll electrode assembly of claim 1.

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