Cylindrical nonaqueous electrolyte secondary battery

Abstract

Provided is a cylindrical nonaqueous electrolyte secondary battery for which corrosion of an opening end of an outer can is suppressed. A cylindrical nonaqueous electrolyte secondary battery as an example embodiment of this invention includes: an outer can having a bottomed cylindrical shape and a groove part at an opening part; a nonaqueous electrolyte and an electrode body housed in the outer can; and a sealing body closing the opening part of the outer can. The electrode body has a winding structure. A tape for fixing a winding end of the electrode body is stuck to an outer peripheral surface of the electrode body. The tape has an extended part that extends out from an end on the groove part side of the outer peripheral surface. The extended part contacts the groove part and absorbs the nonaqueous electrolyte.

Description

Cylindrical non-aqueous electrolyte secondary battery

[0001] The present disclosure relates to a cylindrical non-aqueous electrolyte secondary battery, and more particularly to a non-aqueous electrolyte secondary battery in which corrosion of an outer can is suppressed.

[0002] A cylindrical nonaqueous electrolyte secondary battery contains a wound electrode assembly and a nonaqueous electrolyte in a cylindrical outer can with a bottom, and a sealing member is crimped and fixed between the grooved portion and the open end of the outer can via a gasket, thereby sealing the interior. Generally, the end of the wound electrode assembly is fixed with tape. For example, in Patent Document 1, tape is attached near both axial ends of the electrode assembly.

[0003] International Publication No. 2018 / 168628

[0004] During battery manufacturing, nonaqueous electrolyte injected into the outer can may remain on the opening of the outer can. If nonaqueous electrolyte remains at the open edge of the outer can, it may react with moisture in the air to produce hydrofluoric acid, which may corrode the open edge. After extensive research, the inventors discovered a method in which a tape attached to the outer surface of the electrode assembly extends from the edge on the grooved portion side, allowing the tape to absorb the remaining nonaqueous electrolyte. This simple method can suppress corrosion of the open edge.

[0005] The cylindrical nonaqueous electrolyte secondary battery according to the present disclosure comprises a cylindrical, bottomed outer can having a grooved portion at its opening, an electrode assembly and nonaqueous electrolyte solution housed in the outer can, and a sealing body that closes the opening of the outer can, wherein the electrode assembly has a wound structure, and tape is attached to the outer peripheral surface of the electrode assembly to secure the winding end of the electrode assembly, and the tape has an extension portion that extends from the end of the outer peripheral surface on the grooved portion side, and the extension portion contacts the grooved portion and absorbs the nonaqueous electrolyte solution.

[0006] According to the cylindrical nonaqueous electrolyte secondary battery according to the present disclosure, corrosion of the open end of the outer can can be suppressed.

[0007] 1 is an axial cross-sectional view of a cylindrical nonaqueous electrolyte secondary battery according to an embodiment of the present invention; FIG. 2 is a perspective view of an electrode body according to an embodiment of the present invention; FIG. 3 is an enlarged view of the vicinity of an opening of an outer can in FIG.

[0008] Hereinafter, an example of an embodiment of a cylindrical nonaqueous electrolyte secondary battery according to the present disclosure will be described in detail with reference to the drawings. The embodiment described below is merely an example, and the present disclosure is not limited to the following embodiment. Furthermore, the present disclosure also includes embodiments obtained by selectively combining the components of the embodiments described below.

[0009] FIG. 1 is a schematic diagram illustrating an axial cross section of a secondary battery 10 according to an embodiment. As shown in FIG. 1 , the secondary battery 10 includes an electrode assembly 14 having a wound structure, a nonaqueous electrolyte, and a cylindrical outer can 16 with a bottom that accommodates the electrode assembly 14 and the nonaqueous electrolyte. The electrode assembly 14 includes a positive electrode 11, a negative electrode 12, and a separator 13, and is configured such that the positive electrode 11 and the negative electrode 12 are spirally wound with the separator 13 interposed therebetween. The outer can 16 is a cylindrical metal container with a bottom that is open on one axial side, and the opening of the outer can 16 is closed by a sealing member 17. Hereinafter, for convenience of explanation, the sealing member 17 side of the secondary battery 10 is referred to as the top, and the bottom side of the outer can 16 is referred to as the bottom.

[0010] As the non-aqueous solvent (organic solvent) of the non-aqueous electrolyte, carbonates, lactones, ethers, ketones, esters, etc. can be used, and two or more of these solvents can be mixed and used. When two or more solvents are mixed and used, it is preferable to use a mixed solvent containing a cyclic carbonate and a chain carbonate. For example, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc. can be used as the cyclic carbonate, and dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), etc. can be used as the chain carbonate. As the electrolyte salt of the non-aqueous electrolyte, LiPF ６ , LiBF ４ , LiCF ３ SO ３ The amount of electrolyte salt dissolved in the non-aqueous solvent can be, for example, 0.5 to 2.0 mol / L.

[0011] The positive electrode 11, negative electrode 12, and separator 13 that make up the electrode assembly 14 are all long, strip-like bodies that are spirally wound and alternately stacked in the radial direction of the electrode assembly 14. The negative electrode 12 is formed to be slightly larger than the positive electrode 11 in order to prevent lithium deposition. That is, the negative electrode 12 is formed to be longer in the length direction and width direction (short direction) than the positive electrode 11. The separator 13 is formed to be at least slightly larger than the positive electrode 11, and two separators 13 are arranged to sandwich the positive electrode 11. The secondary battery 10 includes insulating plates 18 and 19 arranged above and below the electrode assembly 14, respectively.

[0012] The electrode body 14 has a positive electrode lead 20 connected to the positive electrode 11 by welding or the like, and a negative electrode lead 21 connected to the negative electrode 12 by welding or the like. In this embodiment, the positive electrode lead 20 is connected to the center of the positive electrode 11 in the longitudinal direction, and the negative electrode lead 21 is connected to the end of the negative electrode 12 in the longitudinal direction that is located on the winding core side of the electrode body 14.

[0013] The positive electrode 11 has a positive electrode current collector 30 and a positive electrode mixture layer 31 formed on the positive electrode current collector 30. The positive electrode current collector 30 can be a foil of a metal, such as aluminum or an aluminum alloy, that is stable within the potential range of the positive electrode 11, or a film having such a metal disposed on its surface. The positive electrode mixture layer 31 contains a positive electrode active material, a conductive agent, and a binder, and is preferably formed on both sides of the positive electrode current collector 30 except for the portion to which the positive electrode lead 20 is welded. The positive electrode 11 can be produced, for example, by applying a positive electrode mixture slurry containing a positive electrode active material, a conductive agent, a binder, etc. to the positive electrode current collector 30, drying the coating, and then compressing it to form the positive electrode mixture layer 31 on both sides of the positive electrode current collector 30.

[0014] The positive electrode mixture layer 31 generally contains particulate lithium metal composite oxide as the positive electrode active material. The lithium metal composite oxide is a composite oxide containing metal elements such as Co, Mn, Ni, and Al in addition to Li. The metal element constituting the lithium metal composite oxide is, for example, at least one selected from Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y, Zr, Sn, Sb, W, Pb, and Bi. Among these, it is preferable to contain at least one selected from Co, Ni, and Mn. Examples of suitable composite oxides include lithium metal composite oxides containing Ni, Co, and Mn, and lithium metal composite oxides containing Ni, Co, and Al.

[0015] The negative electrode 12 has a negative electrode current collector 40 and a negative electrode mixture layer 41 formed on the negative electrode current collector 40. The negative electrode current collector 40 can be a foil of a metal, such as copper or a copper alloy, that is stable within the potential range of the negative electrode 12, or a film having such a metal disposed on its surface. The negative electrode mixture layer 41 contains a negative electrode active material, a binder, and, if necessary, a conductive agent, and is preferably formed on both sides of the negative electrode current collector 40, excluding an exposed portion 42 (described below) and a portion to which the negative electrode lead 21 is welded. The negative electrode 12 can be produced by applying a negative electrode mixture slurry containing the negative electrode active material and the binder to the surface of the negative electrode current collector 40, drying the coating, and then compressing it to form the negative electrode mixture layer 41 on both sides of the negative electrode current collector 40.

[0016] The negative electrode mixture layer 41 generally contains, as the negative electrode active material, a carbon material that reversibly absorbs and releases lithium ions. A suitable example of the carbon material is graphite, such as natural graphite or artificial graphite. Alternatively, the negative electrode active material may be a material containing at least one of an element that alloys with Li, such as Si or Sn, and a material containing such an element. Among these, a composite material containing Si is preferred. A suitable Si-containing composite material is a composite particle containing an ion-conducting phase and a Si phase dispersed in the ion-conducting phase. A carbon material and a Si-containing composite material may be used together as the negative electrode active material, which is preferable from the viewpoint of achieving both high capacity and high durability of the battery.

[0017] A porous sheet having ion permeability and insulating properties is used for the separator 13. Specific examples of the porous sheet include a microporous thin film, a woven fabric, and a nonwoven fabric. Suitable materials for the separator 13 include polyolefins such as polyethylene and polypropylene, and cellulose. The separator 13 may have a single-layer structure or a multi-layer structure. A highly heat-resistant resin layer such as an aramid resin may be formed on the surface of the separator 13. A filler layer containing an inorganic filler may be formed at the interface between the separator 13 and at least one of the positive electrode 11 and the negative electrode 12.

[0018] The negative electrode 12 is disposed on the outer peripheral surface of the electrode body 14, and an exposed portion 42 is formed where the surface of the negative electrode current collector 40 is exposed. The exposed portion 42 may be formed on a part of the outer peripheral surface of the electrode body 14, but is preferably formed on the entire outer peripheral surface. The exposed portion 42 may be formed on only one side (outer surface) of the negative electrode current collector 40 facing outward from the electrode body 14, or may be formed on both sides of the negative electrode current collector 40. The exposed portion 42 is formed, for example, within a range of a length equivalent to one to two circumferences of the electrode body 14 from the longitudinal end of the negative electrode 12 located on the outer peripheral surface of the electrode body 14.

[0019] In the secondary battery 10, the exposed portion 42 of the negative electrode 12 contacts the inner surface of the outer can 16, and the negative electrode lead 21 is connected by welding or the like to the inner bottom surface of the outer can 16. For example, the exposed portion 42 contacts the inner surface of the outer can 16 along the entire outer periphery of the electrode body 14. The positive electrode lead 20 passes through the through hole of the insulating plate 18 and extends toward the sealing body 17, and is connected by welding or the like to the underside of the internal terminal plate 23, which is the bottom plate of the sealing body 17. Therefore, in this embodiment, the sealing body 17 serves as a positive electrode external terminal, and the outer can 16 serves as a negative electrode external terminal.

[0020] As described above, the outer can 16 is a cylindrical metal container with a bottom and an opening on one axial side. A gasket 28 is provided between the outer can 16 and the sealing body 17 to ensure sealing of the battery interior and insulation between the outer can 16 and the sealing body 17. A groove 22 is formed at the opening of the outer can 16, with part of the side surface protruding inward to support the sealing body 17. The groove 22 is preferably formed in an annular shape along the circumferential direction of the outer can 16, and its top surface supports the sealing body 17. The groove 22 is formed in an annular shape around the entire circumference of the outer can 16, for example, by spinning. The sealing body 17 is fixed to the top of the outer can 16 by the groove 22 and the open end of the outer can 16, which is crimped to the sealing body 17.

[0021] The sealing body 17 has a structure in which, in order from the electrode body 14 side, an internal terminal plate 23, a lower valve body 24, an insulating member 25, an upper valve body 26, and a cap 27 are stacked. Each member constituting the sealing body 17 has, for example, a disk or ring shape, and each member except for the insulating member 25 is electrically connected to one another. The lower valve body 24 and the upper valve body 26 are connected at their respective centers, and the insulating member 25 is interposed between their respective peripheral edges. If an abnormality occurs in the battery and the internal pressure increases, the lower valve body 24 deforms and breaks, pushing the upper valve body 26 toward the cap 27, thereby interrupting the current path between the lower valve body 24 and the upper valve body 26. If the internal pressure further increases, the upper valve body 26 breaks, and gas is discharged from the opening of the cap 27.

[0022] Tapes 50 and 55 are attached to the outer peripheral surface of the electrode body 14. The tapes 50 and 55 are each attached to the axial end portions of the outer peripheral surface of the electrode body 14, with tape 50 being provided on the grooved portion 22 side of the outer can 16 and tape 55 being provided on the bottom side of the outer can 16. As will be described in detail later, tape 50 extends from the end of the outer peripheral surface of the electrode body 14 on the grooved portion 22 side, and this extended portion contacts the grooved portion 22.

[0023] The tapes 50 and 55 will be described in detail below with reference to Fig. 2. Fig. 2 is a perspective view of the electrode body 14.

[0024] As shown in Fig. 2, the tapes 50 and 55 are stop tapes that secure the winding end 12x of the wound structure of the electrode assembly 14 and maintain the wound structure of the electrode assembly 14. In this embodiment, the outer peripheral surface of the electrode assembly 14 is formed by the exposed portion 42 of the negative electrode 12, and the longitudinal end of the negative electrode 12 is the winding end 12x of the wound structure. The tapes 50 and 55 are attached to the outer peripheral surface (exposed portion 42) of the electrode assembly 14 so as to straddle the winding end 12x, and secure the winding end 12x to a portion of the outer peripheral surface of the electrode assembly 14 that is located inside the winding end 12x.

[0025] The tapes 50 and 55 are formed in a strip shape. The tapes 50 and 55 are preferably provided so that their length direction follows the circumferential direction of the electrode body 14 and are spaced apart from each other in the axial direction of the electrode body 14. The tape 50 is attached to the upper end (one axial end) of the electrode body 14, and the tape 55 is attached to the lower end (the other axial end) of the electrode body 14. In this case, the wound structure of the electrode body 14 is stably maintained. Furthermore, the axial end of the electrode body 14 is prevented from hitting the edge of the outer can 16 and being turned over, making it easier to insert the electrode body 14 into the outer can 16.

[0026] The tape 50 is attached so as to cross the winding end 12x along the circumferential direction of the electrode body 14. The length of the tape 50 along the circumferential direction of the electrode body 14 is preferably 90% or more of the circumferential length of the outer circumferential surface. This allows the tape 50 to absorb any nonaqueous electrolyte remaining anywhere along the circumferential direction of the outer can 16. In this case, even if nonaqueous electrolyte remains near a portion where the tape 50 is not present, the nonaqueous electrolyte will move and be absorbed by the tape 50 when the sealing body 17 is crimped.

[0027] The length of tape 50 along the circumferential direction of electrode body 14 is preferably 100% or less of the circumferential length of the outer circumferential surface. If the length of tape 50 exceeds 100% of the circumferential length of electrode body 14, tapes 50 will overlap, which may make it difficult to insert electrode body 14 into outer can 16. The length of tape 55 may be the same as or different from tape 50. Tape 55 does not require the function of absorbing nonaqueous electrolyte like tape 50, and therefore may be applied across winding end 12x and may have a length that does not cause any problems as a winding stop tape.

[0028] The tapes 50 and 55 have a width equivalent to, for example, 5% to 25% of the axial length of the electrode body 14. The width of the tapes 50 and 55 is preferably substantially constant over the entire length. The widths of the tapes 50 and 55 may be the same or different. When the widths of the portions attached to the outer peripheral surface of the electrode body 14 are the same, the tape 50 is wider than the tape 55 by the amount that extends beyond the edge of the outer peripheral surface on the grooved portion 22 side. The tape 55 is generally attached with a predetermined gap (for example, 1 mm or less) between it and the lower end of the outer peripheral surface to allow for attachment error.

[0029] The tape 50 will be described in further detail below with reference to Figures 2 and 3. Figure 3 is an enlarged view of the vicinity of the opening of the exterior can 16 in Figure 1.

[0030] 2 and 3 , the tape 50 attached to the upper end of the electrode assembly 14 has an extension 53 extending from the grooved end of the outer circumferential surface of the electrode assembly 14. The extension 53 contacts the grooved portion 22 of the outer can 16 and absorbs the nonaqueous electrolyte remaining in the grooved portion 22 after the nonaqueous electrolyte is injected into the secondary battery 10. In other words, the tape 50 functions as a stop tape that maintains the wound structure of the electrode assembly 14, while also functioning as an absorbent to suppress corrosion of the open end of the outer can. The tape 50 is attached to the outer circumferential surface of the electrode assembly 14 and is integrated with the electrode assembly 14.

[0031] The tape 50 includes, for example, a tape substrate 51 and an adhesive layer 52 provided on one surface of the tape substrate 51. The tape substrate 51 is configured, for example, of a single-layer or multi-layer resin substrate. The adhesive layer 52 is formed, for example, by applying an adhesive to one surface of the tape substrate 51.

[0032] The resin constituting the tape substrate 51 is not particularly limited as long as it absorbs the non-aqueous electrolyte. The resin constituting the tape substrate 51 is, for example, a resin that absorbs the non-aqueous electrolyte and swells. The resin constituting the tape substrate 51 is, for example, one or more resins selected from the group consisting of polyurethane resin, polystyrene resin, fluororesin, and polyether resin. An example of the fluororesin is PVDF, and an example of the polyether resin is thoxyoligoethyleneoxypolyphosphazene.

[0033] The adhesive constituting the adhesive layer 52 may be a hot-melt type that develops adhesiveness when heated or a thermosetting type that hardens when heated, but is preferably one that has adhesiveness at room temperature from the viewpoint of productivity, etc. Examples of adhesives constituting the adhesive layer 52 include acrylic adhesives and synthetic rubber adhesives.

[0034] The thickness of the tape 50 is, for example, 10 μm to 100 μm, and preferably 20 μm to 70 μm. The thickness of the tape substrate 51 is greater than the thickness of the adhesive layer 52, and is, for example, 10 μm to 65 μm. The thickness of the adhesive layer 52 is, for example, 5 μm to 30 μm.

[0035] After the electrode body 14 with the tape 50 attached is housed in the outer can 16, a groove 22 is formed in the outer can 16, and the extending portion 53 of the tape 50 is folded radially inward of the electrode body 14 along the groove 22. At this time, if the extending portion 53 sticks to the electrode body 14, it is expected that the extending portion 53 will not be able to be folded properly along the groove 22. For this reason, it is preferable that the extending portion 53 does not have adhesive strength to the electrode body 14.

[0036] In this embodiment, the adhesive layer 52 is not provided on the extension portion 53, but is provided only on the portion facing the outer peripheral surface of the electrode body 14. The extension portion 53 is composed of only the tape substrate 51. The tape 50 may be attached to the outer peripheral surface over the entire area of ​​the portion facing the outer peripheral surface of the electrode body 14. Alternatively, the adhesive layer 52 may be provided over the entire area of ​​one side of the tape substrate 51, and the adhesive layer 52 may be covered in the extension portion 53 with a coating layer that does not have adhesive strength. For example, the same resin substrate as the tape substrate 51 may be used for the coating layer.

[0037] As described above, the tape 50 has a portion facing the outer peripheral surface of the electrode assembly 14 and an extension portion 53 extending from the upper end of the outer peripheral surface. As shown in FIG. 2 , the extension portion 53 extends in the axial direction of the electrode assembly 14 from the upper end of the outer peripheral surface before the electrode assembly 14 is housed in the outer can 16. As shown in FIG. 3 , after the electrode assembly 14 is housed in the outer can 16, when the grooved portion 22 is machined in the outer can 16, the extension portion 53 bends radially inward of the electrode assembly 14 along the grooved portion 22 and comes into contact with the grooved portion 22. When a nonaqueous electrolyte is subsequently injected into the outer can 16, there is a risk that the nonaqueous electrolyte will remain in the grooved portion 22. However, the extension portion 53 absorbs the nonaqueous electrolyte remaining in the grooved portion 22, thereby preventing the nonaqueous electrolyte from reaching the open end of the outer can 16 and thereby preventing corrosion of the open end.

[0038] It is preferable that the extending portion 53 extends along the grooved portion 22 and beyond the tip T of the grooved portion 22. The tip T of the grooved portion 22 is the part of the grooved portion 22 that is located most radially inward. In this case, the extending portion 53 can more reliably absorb the nonaqueous electrolyte remaining in the grooved portion 22.

[0039] Tape 55 may be a tape having the same composition as tape 50, or may be a tape generally used as a winding stop tape. Tape 55 includes, for example, a tape substrate and an adhesive layer provided on one side of the tape substrate. Examples of resins constituting the tape substrate of tape 55 include polyesters such as polyethylene terephthalate (PET), polypropylene (PP), polyimide (PI), polyphenylene sulfide (PPS), polyetherimide (PEI), and polyamide. Examples of adhesives constituting the adhesive layer of tape 55 include acrylic adhesives and synthetic rubber adhesives.

[0040] As described above, with the secondary battery 10 having the above configuration, corrosion of the open end of the outer can 16 can be suppressed by utilizing the stop tape 50. The tape 50 is attached to the outer peripheral surface of the electrode body 14 and is integrated with the electrode body 14, and when the grooved portion 22 is formed, the extending portion 53 comes into contact with the grooved portion 22. This allows the extending portion 53 to absorb the nonaqueous electrolyte remaining in the grooved portion 22.

[0041] The above-described embodiment can be appropriately modified in design without impairing the object of the present disclosure. For example, in the above-described embodiment, the outer peripheral surface of the electrode body 14 is the exposed portion 42 of the negative electrode 12, but the outer peripheral surface may be the separator 13. In this case, the same configuration as in the above-described embodiment can be applied to the tape 50. Furthermore, in the above-described embodiment, the outer can 16 functions as the negative electrode external terminal, but it is also possible to connect the positive electrode lead 20 to the outer can 16 to serve as the positive electrode external terminal.

[0042] The present disclosure is further described by the following embodiments. Configuration 1: A cylindrical nonaqueous electrolyte secondary battery comprising: a cylindrical outer can with a bottom and a grooved opening; an electrode assembly and nonaqueous electrolyte solution housed in the outer can; and a sealing member that closes the opening of the outer can, wherein the electrode assembly has a wound structure, and a tape is attached to the outer peripheral surface of the electrode assembly to secure the winding end of the electrode assembly, and the tape has an extension extending from the end of the outer peripheral surface facing the grooved portion, and the extension contacts the grooved portion and absorbs the nonaqueous electrolyte solution. Configuration 2: The cylindrical nonaqueous electrolyte secondary battery according to Configuration 1, wherein the tape includes a tape substrate and an adhesive layer provided on one side of the tape substrate, and the extension does not have adhesive strength to the electrode assembly. Configuration 3: The cylindrical nonaqueous electrolyte secondary battery according to Configuration 1 or 2, wherein the length of the tape along the circumferential direction of the electrode assembly is 90% or more of the circumferential length of the outer peripheral surface. Configuration 4: The cylindrical nonaqueous electrolyte secondary battery according to configuration 1 or 2, wherein the length of the tape along the circumferential direction of the electrode body is 100% or less of the circumferential length of the outer circumferential surface.

[0043] REFERENCE SIGNS LIST 10 Cylindrical non-aqueous electrolyte secondary battery, 11 Positive electrode, 12 Negative electrode, 12x Winding end, 13 Separator, 14 Electrode body, 16 Outer can, 17 Sealing body, 18, 19 Insulating plate, 20 Positive electrode lead, 21 Negative electrode lead, 22 Grooved portion, 23 Internal terminal plate, 24 Lower valve body, 25 Insulating member, 26 Upper valve body, 27 Cap, 28 Gasket, 30 Positive electrode current collector, 31 Positive electrode mixture layer, 40 Negative electrode current collector, 41 Negative electrode mixture layer, 42 Exposed portion, 50, 55 Tape, 51 Tape substrate, 52 Adhesive layer, 53 Extension portion, T Tip

Claims

1. A cylindrical nonaqueous electrolyte secondary battery comprising: a cylindrical exterior can with a bottom and a groove at an opening; an electrode assembly and nonaqueous electrolyte contained in the exterior can; and a sealing body that closes the opening of the exterior can, wherein the electrode assembly has a wound structure, and a tape is attached to an outer peripheral surface of the electrode assembly for fixing an end of the electrode assembly that is wound, the tape has an extension portion that extends from an end of the outer peripheral surface that faces the groove portion, and the extension portion contacts the groove portion and absorbs the nonaqueous electrolyte.

2. The cylindrical nonaqueous electrolyte secondary battery according to claim 1, wherein the tape includes a tape base material and an adhesive layer provided on one side of the tape base material, and the extension portion has no adhesive strength with respect to the electrode body.

3. The cylindrical nonaqueous electrolyte secondary battery according to claim 1, wherein the length of said tape along the circumferential direction of said electrode body is 90% or more of the circumferential length of said outer circumferential surface.

4. The cylindrical nonaqueous electrolyte secondary battery according to claim 1, wherein the length of said tape along the circumferential direction of said electrode body is 100% or less of the circumferential length of said outer circumferential surface.

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