Non-aqueous electrolyte secondary battery

Abstract

To provide a non-aqueous electrolyte secondary battery that can suppress damage to an electrode body near the end of an insulating tape caused by repeated charging and discharging.SOLUTION: A non-aqueous electrolyte secondary battery 10 includes an outer casing 15, a wound electrode assembly 14 housed in the outer casing 15 and formed by winding a positive electrode 11 and a negative electrode 12 with a separator 13 interposed therebetween, and an insulating tape 30 attached to the electrode assembly 14, the insulating tape 30 includes a base layer 40 having a first main surface 44a, a second main surface 44b opposite the first main surface 44a, and a side surface 46 extending from an edge of the first main surface 44a to an edge of the second main surface 44b, and an adhesive layer 42 provided on the first main surface 44a of the base layer 40, the side surface 46 of the base layer 40 is inclined at an angle ranging from 40° to 80° or from 100° to 140° relative to the first main surface 44a and the second main surface 44b of the base layer 40.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a non-aqueous electrolyte secondary battery.

Background Art

[0002] Conventionally, a non-aqueous electrolyte secondary battery in which a wound electrode body in which a positive electrode and a negative electrode are wound via a separator is housed in an exterior body has been widely used.

[0003] Patent Documents 1 and 2 disclose an insulating tape that is attached to the electrode body so as to fix the winding end portion of the electrode body so that the winding of the electrode body after winding does not loosen.

[0004] Also, Patent Documents 3 to 5 disclose an insulating tape that is attached to the positive electrode constituting the electrode body so as to cover the positive electrode lead connected to the positive electrode so as to improve the insulation between the positive electrode lead and the negative electrode.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0006] Incidentally, when non-aqueous electrolyte secondary batteries undergo repeated charging and discharging, the electrode body expands and contracts repeatedly, and the electrode body is repeatedly subjected to pressure from the outer casing. When the electrode body is repeatedly subjected to pressure from the outer casing, stress is placed on the insulating tape attached to the electrode body, and this can cause damage to the electrode body due to steps at the edges of the insulating tape. Such damage to the electrode body may lead to a decrease in the reliability and safety of the battery.

[0007] Therefore, the object of this disclosure is to provide a non-aqueous electrolyte secondary battery that can suppress damage to the electrode body near the end of the insulating tape caused by repeated charging and discharging. [Means for solving the problem]

[0008] A non-aqueous electrolyte secondary battery according to one aspect of the present disclosure comprises an outer casing, a wound electrode body housed in the outer casing and having a positive electrode and a negative electrode wound around a separator, and an insulating tape attached to the electrode body, wherein the insulating tape has a base layer having a first main surface, a second main surface opposite to the first main surface, and a side surface extending from the edge of the first main surface to the edge of the second main surface, and an adhesive layer provided on the first main surface of the base layer, the side surface of the base layer being inclined with respect to the first and second main surfaces of the base layer in the range of 40° to 80° or 100° to 140°. [Effects of the Invention]

[0009] The non-aqueous electrolyte secondary battery described herein can suppress damage to the electrode body near the end of the insulating tape caused by repeated charging and discharging. [Brief explanation of the drawing]

[0010] [Figure 1] This is a cross-sectional view of a non-aqueous electrolyte secondary battery, which is an example of an embodiment. [Figure 2] Figure 1 is a perspective view of the electrode body shown. [Figure 3] This is a cross-sectional view along the line L1-L1 in Figure 2. [Figure 4] This is a partial top view of the positive electrode at the location where the positive electrode tab is attached, observed from one side of the main surface. [Figure 5] This is a cross-sectional view along the line L1-L1 in Figure 4. [Figure 6] This is a partial top view of the starting end of the positive electrode winding, observed from one of the main surfaces. [Figure 7] This is a cross-sectional view along the line L1-L1 in Figure 6. [Figure 8] This is a cross-sectional view showing an example of the configuration of the insulating tape used in this embodiment. [Figure 9] This is a cross-sectional view showing another example of the insulating tape used in this embodiment. [Modes for carrying out the invention]

[0011] In the following, an example of an embodiment of the non-aqueous electrolyte secondary battery according to this disclosure will be described with reference to the drawings. In the following description, specific shapes, materials, numerical values, directions, etc., are examples to facilitate understanding of this disclosure and can be appropriately modified to suit the specifications of the non-aqueous electrolyte secondary battery. Furthermore, if the following description includes multiple embodiments and modifications, it is intended from the outset that their characteristic parts may be used in appropriate combinations.

[0012] Figure 1 is a cross-sectional view of a non-aqueous electrolyte secondary battery, which is an example of an embodiment. The non-aqueous electrolyte secondary battery 10 shown in Figure 1 comprises an electrode body 14, a non-aqueous electrolyte (not shown), insulating plates 17 and 18 positioned above and below the electrode body 14, respectively, an outer casing 15 housing these components, and a sealing body 16 that closes the opening of the outer casing 15. The electrode body 14 has a wound-type structure in which a positive electrode 11 and a negative electrode 12 are wound around a separator 13. Although the electrode body 14 shown in Figure 1 is cylindrical, it may also have other shapes, such as a flattened shape.

[0013] The outer package 15 is, for example, a bottomed cylindrical metal outer can. Note that the outer package 15 may be square. A gasket 27 is provided between the outer package 15 and the sealing body 16 to ensure the airtightness inside the battery. The outer package 15 has, for example, a groove portion 21 that supports the sealing body 16, where a part of the side surface portion protrudes inward. The groove portion 21 is preferably formed in an annular shape along the circumferential direction of the outer package 15, and supports the sealing body 16 via the gasket 27 on its upper surface.

[0014] The sealing body 16 has a filter 22, a lower valve body 23, an insulating member 24, an upper valve body 25, and a cap 26, which are laminated in order from the electrode body 14 side. Each member constituting the sealing body 16 has, for example, a disc shape or a ring shape, and each member except the insulating member 24 is electrically connected to each other. The lower valve body 23 and the upper valve body 25 are connected to each other at their central portions, and an insulating member 24 is interposed between the peripheral edges of each. When the internal pressure of the battery rises due to heat generation caused by an internal short circuit or the like, for example, the lower valve body 23 breaks, and as a result, the upper valve body 25 bulges toward the cap 26 side and separates from the lower valve body 23, thereby cutting off the electrical connection between the two. When the internal pressure further rises, the upper valve body 25 breaks, and gas is discharged from the opening 26a of the cap 26.

[0015] In the non-aqueous electrolyte secondary battery 10 shown in FIG. 1, a positive electrode tab 19 is attached to the positive electrode 11. The positive electrode tab 19 attached to the positive electrode 11 passes through the through-hole of the insulating plate 17 and is welded to the lower surface of the filter 22, which is the bottom plate of the sealing body 16. Thereby, the cap 26, which is the top plate of the sealing body 16 electrically connected to the filter 22, becomes the positive electrode terminal. On the other hand, a negative electrode tab 20 is attached to the negative electrode 12. The negative electrode tab 20 attached to the negative electrode 12 passes through the through-hole of the insulating plate 18 and is welded to the inner surface of the bottom of the outer package 15. Thereby, the outer package 15 becomes the negative electrode terminal.

[0016] FIG. 2 is a perspective view of the electrode body shown in FIG. 1. FIG. 3 is a cross-sectional view taken along line L1-L1 in FIG. 2. As described above, the electrode body 14 has a winding structure in which the positive electrode 11 and the negative electrode 12 are wound in a spiral shape with the separator 13 interposed therebetween. The positive electrode 11, the negative electrode 12, and the separator 13 are all formed in a strip shape and are wound in a spiral shape around the core disposed along the winding axis, so that they are alternately laminated in the radial direction of the electrode body 14. In the electrode body 14 shown in FIG. 2, the negative electrode 12 is wound so as to be the outermost peripheral surface of the electrode body 14. In the electrode body 14, the longitudinal direction of the positive electrode 11 and the negative electrode 12 is the winding direction, and the width direction of the positive electrode 11 and the negative electrode 12 is the axial direction.

[0017] As shown in FIGS. 2 and 3, an insulating tape 30 is attached to the outermost peripheral surface of the electrode body 14 so as to fix the winding end portion 14a of the electrode body 14 to the electrode body 14. The winding end portion 14a of the electrode body 14 shown in FIG. 2 is the winding end portion of the negative electrode 12 which is the outermost peripheral surface of the electrode body 14. Therefore, it can be said that the insulating tape 30 is attached to the outermost peripheral surface of the electrode body 14 so as to fix the winding end portion of the negative electrode 12 to the electrode body 14. However, the outermost peripheral surface and the winding end portion 14a of the electrode body 14 are not limited to the negative electrode 12, and may be the separator 13 or the positive electrode 11. Even in such a case, similarly, the insulating tape 30 may be applied. In any case, by attaching the insulating tape 30 to the outermost peripheral surface of the electrode body 14 so as to fix the winding end portion 14a of the electrode body 14 to the electrode body 14, the unwinding of the wound electrode body 14 can be suppressed.

[0018] The position and number of the insulating tapes 30 are not particularly limited as long as the winding end portion 14a can be fixed. For example, as shown in FIG. 2, one insulating tape may be provided at each of both axial ends of the electrode body 14, or may be provided at either one of the axial ends of the electrode body 14.

[0019] The length of the insulating tape 30 is preferably close to the circumference (the length of one turn) of the outermost peripheral surface of the electrode body 14, and may be shorter than the length of the outermost periphery of the electrode body 14 so that one end and the other end in the longitudinal direction do not overlap as shown in FIG. 2.

[0020] The width of the insulating tape 30 is preferably 10% to 40% of the height of the electrode body 14. The width of the insulating tape 30 is, for example, 3 mm to 30 mm, and may also be 5 mm to 15 mm.

[0021] Figure 4 is a partial top view of the positive electrode at the location where the positive electrode tab is attached, observed from one side of the main surface, and Figure 5 is a cross-sectional view along the line L1-L1 in Figure 4. The positive electrode 11 shown in Figures 4 and 5 is in its state before winding. In addition, in Figure 4, the insulating tape 30 covering the positive electrode tab 19 is shown as a dashed line in a transparency view to clarify the structure of the positive electrode 11.

[0022] The positive electrode 11 comprises a positive electrode current collector 32 and a positive electrode active material layer 34 formed on the positive electrode current collector 32. The positive electrode 11 also has an exposed portion 32a where the positive electrode current collector 32 is exposed, as the positive electrode active material layer 34 is not formed on the positive electrode 11. One end of the positive electrode tab 19 is connected to the exposed portion 32a of the positive electrode current collector 32. The other end of the positive electrode tab 19 is connected to the filter 22 of the sealing body 16 shown in Figure 1, as previously described. The method of connecting the positive electrode tab 19 to the exposed portion 32a is not particularly limited as long as the electrical connection between the positive electrode tab 19 and the positive electrode 11 is ensured; for example, ultrasonic welding is one such method.

[0023] The exposed portion 32a to which the positive electrode tab 19 is connected may be formed at any location on the positive electrode 11, but is generally formed on the longitudinal central side of the positive electrode 11.

[0024] As shown in Figures 4 and 5, the insulating tape 30 is attached to the positive electrode 11 constituting the electrode body 14 so as to cover the exposed portion 32a of the positive electrode current collector 32 and the positive electrode tab 19 located on the exposed portion 32a. By covering the exposed portion 32a and the positive electrode tab 19 on the exposed portion 32a with the insulating tape 30 in this way, the insulation between the positive electrode 11 and the negative electrode 12 can be improved, for example. Also, as shown in Figures 4 and 5, the insulating tape 30 may extend over the positive electrode active material layer 34 side so as to cover the boundary between the positive electrode active material layer 34 and the exposed portion 32a. By covering the exposed portion 32a and the positive electrode tab 19 on the exposed portion 32a with the insulating tape 30, and by covering the boundary between the positive electrode active material layer 34 and the exposed portion 32a with the insulating tape 30, the insulation between the positive electrode 11 and the negative electrode 12 can be further improved, for example.

[0025] Figure 6 is a partial top view of the starting end of the positive electrode winding, observed from one main surface side, and Figure 7 is a cross-sectional view along the line L1-L1 in Figure 6. The positive electrode shown in Figures 6 and 7 is in its state before winding. In Figure 6, the insulating tape 30 is shown as a dashed line in a transparency view to clarify the configuration of the positive electrode 11.

[0026] As shown in Figures 6 and 7, if the positive electrode active material layer 34 is not formed at the winding start end of the positive electrode 11, and an exposed portion 32a of the positive electrode current collector 32 is formed, the insulating tape 30 may be attached to the positive electrode 11 constituting the electrode body 14 so as to cover the boundary portion 36 between the exposed portion 32a at the winding start end of the positive electrode 11 and the positive electrode active material layer 34. By covering the boundary portion 36 between the positive electrode active material layer 34 and the exposed portion 32a with the insulating tape 30 in this way, the insulation between the positive electrode 11 and the negative electrode 12 can be improved, for example.

[0027] Figures 6 and 7 show a configuration in which an exposed portion 32a is formed at the winding start end of the positive electrode 11. However, the exposed portion 32a is formed in an appropriate location depending on the battery design, etc. For example, it may be formed at the winding end of the positive electrode 11, or it may be formed in the longitudinal center of the positive electrode 11. In any case, the insulating tape 30 may be attached to the positive electrode 11 so as to cover the boundary 36 between the exposed portion 32a where the positive electrode current collector 32 is exposed and the positive electrode active material layer 34.

[0028] Although not shown in the diagram, the negative electrode 12 has a negative electrode current collector and a negative electrode active material layer formed on the negative electrode current collector, and like the positive electrode 11, an exposed portion of the negative electrode current collector may be formed. For example, an exposed portion may be formed at the winding start end of the negative electrode 12. It is desirable that one end of the negative electrode tab 20 be connected to the exposed portion at the winding start end of the negative electrode 12. The other end of the negative electrode tab 20 is connected to the bottom of the outer casing 15 shown in Figure 1, as previously described. The method of connecting the negative electrode tab 20 to the exposed portion is the same as for the positive electrode tab 19, for example, ultrasonic welding.

[0029] Furthermore, for example, an exposed portion of the negative electrode current collector may be formed at the winding end of the negative electrode 12, or the entire outermost surface of the electrode body 14 may be an exposed portion of the negative electrode current collector. This makes it easier to secure a current path to the outer casing 15 via the outermost surface of the negative electrode 12, which may improve the output characteristics of the battery.

[0030] Furthermore, the insulating tape 30 may be attached to the negative electrode so as to cover the boundary between the exposed portion of the negative electrode current collector and the negative electrode active material layer, or it may be attached to the negative electrode so as to cover the exposed portion and the negative electrode tab 20 on the exposed portion.

[0031] The following describes the structure of the insulating tape 30.

[0032] Figure 8 is a cross-sectional view showing an example of an insulating tape used in this embodiment, and Figure 9 is a cross-sectional view showing another example of an insulating tape used in this embodiment. As shown in Figures 8 and 9, the insulating tape 30 has a base layer 40 and an adhesive layer 42 provided on the base layer 40. The adhesive layer 42 is the bonding surface with the electrode body 14.

[0033] The material constituting the base layer 40 is preferably a polymer material in terms of flexibility and strength of the insulating tape 30, and examples include cellulose derivatives (e.g., cellulose ether, cellulose ester, etc.), polyvinyl chloride, polyolefins (e.g., polyethylene, polypropylene, etc.), polystyrene, polyester (e.g., polyethylene terephthalate, etc.), polyimide, polyamide, polyamide-imide, polycarbonate, polyphenylene sulfide, etc. Among these, polyimide and fully aromatic polyamide (aramid) are preferred, and polyimide is particularly preferred. The base layer 40 may contain inorganic particles dispersed in the polymer material. The base layer 40 may have a multilayer structure, for example, a layer containing inorganic particles and a layer containing only polymer material. The thickness of the base layer 40 is, for example, 1 μm to 250 μm, and may be 3 μm to 180 μm.

[0034] The base layer 40 has main surfaces (44a, 44b) and side surfaces 46. The main surfaces are a pair of surfaces consisting of surface 44a on which the adhesive layer 42 is placed and surface 44b opposite to surface 44a. The side surfaces 46 are surfaces that extend from the edge of one surface 44a of the main surfaces to the edge of the other surface 44b, and are inclined non-perpendicular to the main surfaces (44a, 44b). The inclination angle of the side surfaces 46 of the base layer 40 is preferably in the range of 40° to 80° or 100° to 140° with respect to the main surfaces (44a, 44b), for example, in order to effectively suppress damage to the electrode body 14. On the side surfaces 46 of the base layer 40, opposing sides may be inclined in the same direction as shown in Figure 8, or they may be inclined in different directions as shown in Figure 9. The thickness of the base layer 40 is, for example, 1 μm to 125 μm, and may be 2 μm to 125 μm.

[0035] As mentioned above, repeated charging and discharging causes the electrode body 14 to expand and contract, and the electrode body 14 is repeatedly subjected to pressure from the outer casing 15. When the electrode body 14 is repeatedly subjected to pressure from the outer casing 15, stress is applied to the insulating tape 30 attached to the electrode body 14. However, because the side surface 46 of the base layer 40 is inclined not perpendicular to the main surface (44a, 44b), the shear force generated on the side surface 46 of the base layer 40 is mitigated compared to the case where the side surface 46 of the base layer 40 is perpendicular to the main surface (44a, 44b). As a result, damage to the electrode body 14 (essentially the positive electrode 11, negative electrode 12, or separator 13) at the location where the insulating tape 30 is attached is suppressed.

[0036] The material constituting the adhesive layer 42 is not particularly limited as long as it can ensure adhesion between the insulating tape 30 and the electrode body 14. Examples include acrylic resin, natural rubber, synthetic rubber, silicone, epoxy resin, melamine resin, and phenolic resin. These may be used individually or in combination of two or more. In addition to the resin material, the material constituting the adhesive layer 42 may also contain additives such as tackifiers, crosslinking agents, anti-aging agents, colorants, antioxidants, chain transfer agents, plasticizers, softeners, surfactants, and antistatic agents, as well as solvents, as needed. The thickness of the adhesive layer 42 is, for example, 1 μm to 125 μm, or 2 μm to 125 μm.

[0037] The following describes the materials used for the positive electrode 11, negative electrode 12, separator 13, and non-aqueous electrolyte.

[0038] The positive electrode current collector 32 constituting the positive electrode 11 can be made of a metal foil that is stable within the potential range of the positive electrode 11, such as aluminum, or a film with the metal arranged on its surface. The positive electrode active material layer 34 constituting the positive electrode 11 contains positive electrode active material. In addition, the positive electrode active material layer 34 preferably contains a conductive material and a binder. The positive electrode 11 can be manufactured, for example, by applying a positive electrode mixture slurry containing positive electrode active material, a binder, a conductive material, etc., onto the positive electrode current collector 32, drying it to form the positive electrode active material layer 34, and then rolling the positive electrode active material layer 34. The exposed portion 32a of the positive electrode current collector 32 is formed, for example, by intermittent coating, in which the positive electrode mixture slurry is not applied to a part of the positive electrode current collector 32.

[0039] Examples of positive electrode active materials include lithium (Li) and Li composite oxides containing transition metal elements such as cobalt (Co), manganese (Mn), and nickel (Ni). Li composite oxides may also contain other additive elements besides Co, Mn, and Ni, such as aluminum (Al), zirconium (Zr), boron (B), magnesium (Mg), scandium (Sc), yttrium (Y), titanium (Ti), iron (Fe), copper (Cu), zinc (Zn), chromium (Cr), lead (Pb), tin (Sn), sodium (Na), potassium (K), barium (Ba), strontium (Sr), calcium (Ca), tungsten (W), molybdenum (Mo), niobium (Nb), and silicon (Si).

[0040] Examples of conductive materials included in the positive electrode active material layer 34 include carbon black, acetylene black, Ketjen black, and carbon powder such as graphite. These may be used individually or in combination of two or more types.

[0041] Examples of binders included in the positive electrode active material layer 34 include fluororesins such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), polyimide (PI), acrylic resins, polyolefin resins, carboxymethylcellulose (CMC) or its salts, and polyethylene oxide (PEO). These may be used individually or in combination of two or more types.

[0042] The negative electrode current collector constituting the negative electrode 12 can be made of, for example, a metal foil such as copper, or a film with the metal arranged on its surface. The negative electrode active material layer constituting the negative electrode 12 contains, for example, a negative electrode active material. In addition to the negative electrode active material, the negative electrode active material layer may also contain a binder or the like. The negative electrode 12 can be manufactured, for example, by applying and drying a negative electrode mixture slurry containing the negative electrode active material, a binder, etc., onto the negative electrode current collector to form a negative electrode mixture layer, and then rolling this negative electrode mixture layer. The exposed portion of the negative electrode current collector is formed, for example, by intermittent coating, in which the negative electrode mixture slurry is not applied to a part of the negative electrode current collector.

[0043] Examples of negative electrode active materials include carbon materials capable of intercalating and releasing lithium ions, such as graphite, non-graphitizable carbon, easily graphitizable carbon, fibrous carbon, coke, and carbon black. Furthermore, examples of non-carbon negative electrode active materials include silicon, tin, and alloys and oxides mainly composed of these materials.

[0044] The binder included in the negative electrode active material layer may be the same material as in the case of the positive electrode 11, or styrene-butadiene copolymer (SBR) or a modified version thereof may be used. These may be used individually or in combination of two or more types.

[0045] For the separator 13, for example, a porous sheet having ion permeability and insulating properties can be used. Specific examples of porous sheets include microporous membranes, woven fabrics, and nonwoven fabrics. Suitable materials for the separator 13 include polyethylene, olefin resins such as polypropylene, and cellulose. The separator 13 may be a laminate having a cellulose fiber layer and a thermoplastic resin fiber layer such as an olefin resin. Alternatively, it may be a multilayer separator containing a polyethylene layer and a polypropylene layer, or a separator 13 with a material such as aramid resin or ceramic coated on its surface may be used.

[0046] Non-aqueous electrolytes consist of a non-aqueous solvent (organic solvent) and an electrolyte salt. Examples of non-aqueous solvents include carbonates, lactones, ethers, ketones, and esters. These solvents may be used individually or in mixtures of two or more. When using a mixture of two or more solvents, it is preferable to use a mixed solvent containing cyclic carbonates and linear carbonates. Examples of cyclic carbonates include ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC). Examples of linear carbonates include dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC). Examples of electrolyte salts include LiPF6, LiBF4, LiCF3SO3, and mixtures thereof. The solubility of the electrolyte salt in the non-aqueous solvent can be, for example, 0.5 to 2.0 mol / L. [Explanation of Symbols]

[0047] 10 Non-aqueous electrolyte secondary battery, 11 Positive electrode, 12 Negative electrode, 13 Separator, 14 Electrode body, 14a End of winding, 15 Outer casing, 16 Sealing body, 17,18 Insulating plate, 19 Positive electrode tab, 20 Negative electrode tab, 21 Grooved section, 22 Filter, 23 Lower valve body, 24 Insulating member, 25 Upper valve body, 26 Cap, 26a Opening, 27 Gasket, 30 Insulating tape, 32 Positive electrode current collector, 32a Exposed section, 34 Positive electrode active material layer, 36 Boundary section, 40 Base material layer, 42 Adhesive layer, 44a,44b Main surface, 46 Side surface.

Claims

1. A non-aqueous electrolyte secondary battery comprising an outer casing, a wound electrode body housed in the outer casing in which a positive electrode and a negative electrode are wound around each other with a separator in between, and an insulating tape attached to the electrode body, The insulating tape comprises a base layer having a first main surface, a second main surface opposite the first main surface, and a side surface extending from the edge of the first main surface to the edge of the second main surface, and an adhesive layer provided on the first main surface of the base layer. A non-aqueous electrolyte secondary battery, wherein the side surface of the substrate layer is inclined with respect to the first main surface and the second main surface of the substrate layer in a range of 40° to 80° or in a range of 100° to 140°.

2. The non-aqueous electrolyte secondary battery according to claim 1, wherein the side surface has a first side surface and a second side surface that are opposite to each other, and the first side surface and the second side surface are inclined in the same direction.

3. The non-aqueous electrolyte secondary battery according to claim 1, wherein the insulating tape is attached to the end of the winding of the electrode body so as to fix it to the electrode body.

4. At least one of the positive electrode and the negative electrode has a current collector, an active material layer formed on the current collector, and an exposed portion where the active material layer is not formed and the current collector is exposed, and an electrode tab is connected to the exposed portion. The non-aqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein the insulating tape is attached so as to cover the exposed portion and the electrode tab on the exposed portion.

5. At least one of the positive electrode and the negative electrode has a current collector, an active material layer formed on the current collector, and an exposed portion where the active material layer is not formed and the current collector is exposed. The non-aqueous electrolyte secondary battery according to any one of claims 1 to 4, wherein the insulating tape is attached so as to cover the boundary between the exposed portion and the active material layer.

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