Battery

Abstract

To provide a technique to prevent adjacent electrodes from bending together with a tab.SOLUTION: A battery 100 includes a first electrode 5 including a current collector 5a, a second electrode 6 facing the first electrode 5, a tab 15 connected to the first electrode 5 so as to protrude from the first electrode 5, a first protective tape 21 attached to the tab 15, and a second protective tape 23 disposed in a position overlapping with the first protective tape 21. A direction along a longitudinal direction of the tab 15 is defined as a vertical direction; a side where a connection between the first electrode 5 and the tab 15 is located is defined as a lower side; a side where a tip of the tab 15 protruding from the first electrode 5 is located is defined as an upper side; a lower end 21h of the first protective tape 21 is located below an upper end 5k of the current collector 5a so that the first protective tape 21 and the current collector 5a overlap each other; and an upper end 21k of the first protective tape 21 is located above an upper end 6k of the second electrode 6 in the vertical direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to batteries. [Background technology]

[0002] The battery electrodes are fitted with tabs for power extraction. To improve the insulation between the adjacent electrodes and the tabs, the tabs are covered with protective tape. Tabs are sometimes called leads.

[0003] In the nonaqueous electrolyte battery described in Patent Document 1, the protective tape is disposed so as to overlap the positive electrode current collector. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-220862 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, in a cylindrical battery, the positive electrode tab is bent and connected to the center of the sealing plate. When the positive electrode tab is bent, the edge of the negative electrode may be bent along with the positive electrode tab. As a result, the negative electrode may be damaged. This is undesirable from the viewpoint of improving the safety of the battery.

[0006] The present disclosure provides techniques to prevent adjacent electrodes from bending with the tab. [Means for solving the problem]

[0007] The present disclosure provides: a first electrode including a current collector; a second electrode facing the first electrode; a tab connected to the first electrode so as to protrude from the first electrode; a first protective tape attached to the tab; a second protective tape disposed in a position overlapping the first protective tape; Equipped with a direction along the longitudinal direction of the tab is defined as a vertical direction, a side where a connection portion between the first electrode and the tab is located is defined as a lower side, and a side where a tip end portion of the tab protruding from the first electrode is located is defined as an upper side, a lower end of the first protective tape is located below an upper end of the current collector, and thereby the first protective tape and the current collector overlap, an upper end of the first protective tape is located higher than an upper end of the second electrode in the vertical direction; Provide the battery. [Effects of the Invention]

[0008] According to the technique of the present disclosure, it is possible to prevent adjacent electrodes from bending together with the tab. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view of a battery according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a partial plan view of the positive electrode in a state where the electrode group is removed. [Figure 3] FIG. 3 is a partial cross-sectional view of the electrode group taken along line III-III shown in FIG. [Figure 4] FIG. 4 is a diagram illustrating the operation of the battery of this embodiment. [Figure 5A] FIG. 5A is a diagram for explaining the function of the structure of the reference example. [Figure 5B] FIG. 5B is another diagram illustrating the effect of the structure of the reference example. [Figure 6] FIG. 6 is a plan view of a positive electrode according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] (Findings that formed the basis of this disclosure) If a bending point on the positive electrode tab is formed below the top end of the negative electrode, the negative electrode will bend along with the positive electrode tab. On the other hand, if a bending point on the positive electrode tab is formed above the top end of the negative electrode, bending of the negative electrode along with the positive electrode tab can be prevented. In other words, to prevent bending of the negative electrode along with the positive electrode tab, it is important to control the position of the bending point on the positive electrode tab. However, controlling the position of the bending point on the positive electrode tab is not easy. When the diameter of the electrode assembly is small, the positive electrode tab is bent with a large curvature, making it difficult for a bending point on the positive electrode tab to occur below the top end of the negative electrode. The larger the diameter of the electrode assembly, the smaller the curvature of the positive electrode tab, making it more difficult to control the position of the bending point.

[0011] The present disclosure provides techniques for controlling the location of the bend point of the tab to prevent adjacent electrodes from bending with the tab.

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments.

[0013] (Embodiment) FIG. 1 is a cross-sectional view of a battery according to an embodiment of the present disclosure. The battery 100 includes a container 1 and an electrode group 4. The electrode group 4 has a wound structure. The electrode group 4 is housed in the container 1. The electrode group 4 includes a positive electrode 5, a negative electrode 6, and a pair of separators 7. The electrode group 4 is impregnated with an electrolyte. The opening of the container 1 is closed with a sealing plate 2. The positive electrode 5 includes a positive electrode current collector 5a and a positive electrode active material layer 5b. One end of a positive electrode tab 15 is connected to the positive electrode 5. The other end of the positive electrode tab 15 is connected to the back surface of the sealing plate 2. An insulating gasket 3 is disposed around the sealing plate 2. The negative electrode 6 includes a negative electrode current collector 6a and a negative electrode active material layer 6b. One end of a negative electrode tab 16 is connected to the negative electrode 6. The other end of the negative electrode tab 16 is connected to the bottom surface of the container 1. Insulating rings 8 are disposed on the top and bottom surfaces of the electrode group 4.

[0014] In the battery 100, the positive electrode 5 and the negative electrode 6 are the first electrode and the second electrode, respectively, that face each other. However, the positions of the positive electrode 5 and the negative electrode 6 may be interchanged. In this case, the positive electrode 5 and the negative electrode 6 are the second electrode and the first electrode, respectively. The technology of the present disclosure is applicable to both the positive electrode 5 and the negative electrode 6.

[0015] When the electrode group 4 is unfolded and viewed from above, the positive electrode 5 and the negative electrode 6 have a strip-like shape. The width of the negative electrode 6 is wider than the width of the positive electrode 5. The outer edge of the positive electrode 5 in the width direction overlaps with the negative electrode 6. In the width direction, the positive electrode 5 is contained inside the negative electrode 6. The width of the separator 7 is wider than the width of the positive electrode 5 and the width of the negative electrode 6. With this configuration, the safety of the battery 100 is improved.

[0016] The positive electrode current collector 5a can be a sheet or film made of a metal material such as aluminum, stainless steel, titanium, or an alloy thereof. Aluminum and its alloys are suitable materials for the positive electrode current collector 5a because they are inexpensive and easy to form into thin films. The sheet or film may be porous or non-porous. Examples of the sheet or film include metal foil and metal mesh. A carbon material such as carbon may be applied to the surface of the positive electrode current collector 5a as a conductive auxiliary material.

[0017] The positive electrode active material layer 5b is supported on the positive electrode current collector 5a. The positive electrode active material layer 5b contains a positive electrode active material. Examples of the positive electrode active material include lithium-containing transition metal oxides, lithium-containing transition metal phosphates, transition metal fluorides, polyanionic materials, fluorinated polyanionic materials, transition metal sulfides, transition metal oxysulfides, and transition metal oxynitrides. In particular, using a lithium-containing transition metal oxide or a lithium-containing transition metal phosphate as the positive electrode active material can reduce the manufacturing cost of the battery and increase the average discharge voltage. Examples of lithium-containing transition metal oxides include lithium cobalt oxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, and lithium nickel manganese oxide. Examples of lithium-containing transition metal phosphates include lithium iron phosphate, lithium vanadium phosphate, lithium cobalt phosphate, and lithium nickel phosphate.

[0018] The positive electrode active material layer 5b may contain other materials such as a conductive additive and a binder.

[0019] The conductive additive is used to reduce the resistance of the positive electrode 5. Examples of the conductive additive include carbon materials and conductive polymer compounds. Examples of the carbon material include carbon black, graphite, acetylene black, carbon nanotubes, carbon nanofibers, graphene, fullerene, and graphite oxide. Examples of the conductive polymer compound include polyaniline, polypyrrole, and polythiophene.

[0020] The binder is used to improve the binding property of the material constituting the positive electrode 5. Examples of the binder that can be used include polymeric materials such as polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, polytetrafluoroethylene, carboxymethyl cellulose, polyacrylic acid, styrene-butadiene copolymer rubber, polypropylene, polyethylene, and polyimide.

[0021] The negative electrode current collector 6a may be a sheet or film made of a metal material such as stainless steel, nickel, copper, or an alloy thereof. The sheet or film may be porous or non-porous. Examples of the sheet or film include metal foil and metal mesh. A carbon material such as carbon may be applied to the surface of the negative electrode current collector 6a as a conductive auxiliary material.

[0022] The negative electrode active material layer 6b is supported on the negative electrode current collector 6a. The negative electrode active material layer 6b contains a negative electrode active material. The negative electrode active material can be a material capable of absorbing and releasing lithium ions. The negative electrode active material includes, for example, at least one selected from the group consisting of carbon materials and materials capable of forming an alloy with lithium. Examples of carbon materials include graphite. Examples of materials capable of forming an alloy with lithium include silicon, silicon-containing oxides, tin, zinc alloys, bismuth, and germanium. One type selected from these negative electrode active materials may be used, or two or more types may be used in combination.

[0023] The negative electrode active material layer 6b may contain other materials such as a conductive additive, a binder, etc. As the conductive additive and binder, materials that can be used for the positive electrode active material layer 5b can also be used for the negative electrode active material layer 6b.

[0024] The electrolyte is a non-aqueous electrolyte impregnated into the positive electrode 5, the negative electrode 6, and the separator 7. The electrolyte may fill the internal space of the container 1. The electrolyte allows lithium ions to move between the positive electrode 5 and the negative electrode 6.

[0025] The electrolyte solution contains a non-aqueous solvent and a lithium salt.

[0026] Examples of the non-aqueous solvent include cyclic carbonate esters, chain carbonate esters, cyclic ethers, chain ethers, nitriles, amides, etc. One selected from these solvents may be used, or two or more may be used in combination.

[0027] Examples of lithium salts include lithium hexafluorophosphate (LiPF), lithium tetrafluoroborate (LiBF), lithium perchlorate (LiClO), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bisperfluoroethylsulfonylimide (LiN(SO2C2F5)2), LiAsF6, LiCF3SO3, and lithium difluoro(oxalato)borate. One selected from these lithium salts may be used, or two or more may be used in combination.

[0028] The separator 7 has lithium ion conductivity. The material of the separator 7 is not particularly limited as long as it allows the passage of lithium ions. The material of the separator 7 can be at least one selected from the group consisting of a gel electrolyte, an ion exchange resin membrane, a semipermeable membrane, and a porous membrane. If the separator 7 is made of these materials, the safety of the battery 100 can be sufficiently ensured. Examples of gel electrolytes include gel electrolytes containing fluororesins such as PVdF. Examples of ion exchange resin membranes include cation exchange membranes and anion exchange membranes. Examples of porous membranes include porous membranes made of polyolefin resins and porous membranes containing glass paper obtained by weaving glass fibers into nonwoven fabric.

[0029] The container 1 is made of a metal such as aluminum or stainless steel, and may have a cylindrical shape or a rectangular tube shape.

[0030] The electrode group 4 may be wound into a cylindrical shape or an oval shape.

[0031] The positive electrode tab 15 and the negative electrode tab 16 are strip-shaped members. The positive electrode tab 15 is made of a metal material such as aluminum, stainless steel, titanium, or an alloy thereof. The negative electrode tab 16 is made of a metal material such as nickel, a nickel alloy, titanium, a titanium alloy, copper, or a copper alloy.

[0032] FIG. 2 is a partial plan view of the positive electrode 5 with the electrode group 4 unwrapped. FIG. 3 is a partial cross-sectional view of the electrode group 4 taken along line III-III shown in FIG. 2. The positive electrode tab 15 is connected to the positive electrode 5 so as to protrude from the positive electrode 5. Specifically, the positive electrode current collector 5a includes an exposed portion W where the positive electrode active material layer 5b is not provided. The exposed portion W has a rectangular shape in plan view. The positive electrode tab 15 is welded to the positive electrode current collector 5a at the exposed portion W.

[0033] A first protective tape 21 and a second protective tape 23 are attached to the positive electrode tab 15. The first protective tape 21 and the second protective tape 23 serve to prevent the positive electrode tab 15 from coming into contact with the adjacent negative electrode 6 when the positive electrode tab 15 is bent. The second protective tape 23 particularly serves to control the bending point of the positive electrode tab 15. In this embodiment, the second protective tape 23 is disposed in a position overlapping the first protective tape 21. More specifically, the second protective tape 23 is disposed on top of the first protective tape 21. However, the second protective tape 23 may also be disposed between the positive electrode tab 15 and the first protective tape 21.

[0034] The first protective tape 21 and the second protective tape 23 surround a portion of the positive electrode tab 15. The first protective tape 21 and the second protective tape 23 are present 360 degrees around the positive electrode tab 15. In this embodiment, the first protective tape 21 is a strip-shaped tape with an adhesive applied to one side. The strip-shaped first protective tape 21 is bent into a C-shape and attached to the positive electrode tab 15. This causes the positive electrode tab 15 to be sandwiched between the first protective tape 21. Similarly, the second protective tape 23 is a strip-shaped tape with an adhesive applied to one side. The strip-shaped second protective tape 23 is bent into a C-shape and attached to the positive electrode tab 15 from above the first protective tape 21. This causes the positive electrode tab 15 and the first protective tape 21 to be sandwiched between the second protective tapes.

[0035] In this specification, the direction along the longitudinal direction of the positive electrode tab 15 is defined as the vertical direction VD. With respect to the vertical direction VD, the side where the connection portion between the positive electrode 5 and the positive electrode tab 15 is located is defined as the lower side, and the side where the tip of the positive electrode tab 15 protruding from the positive electrode 5 is located is defined as the upper side. The longitudinal direction of the positive electrode tab 15 coincides with the width direction of the positive electrode 5. With reference to FIG. 1 , the side where the sealing plate 2 is located is the upper side, and the side where the bottom of the container 1 is located is the lower side.

[0036] The first protective tape 21 and the second protective tape 23 are arranged to overlap the positive electrode current collector 5a. In the vertical direction VD, the lower end 21h of the first protective tape 21 is located below the upper end 5k of the positive electrode current collector 5a, thereby overlapping the first protective tape 21 and the positive electrode current collector 5a. The lower end 23h of the second protective tape 23 is located below the upper end 5k of the positive electrode current collector 5a, thereby overlapping the second protective tape 23 and the positive electrode current collector 5a. The upper end 21k of the first protective tape 21 is located above the upper end 6k of the negative electrode 6. This configuration can reinforce the rigidity of the positive electrode tab 15 in the area where the second protective tape 23 is provided. Therefore, when the positive electrode tab 15 is bent, the negative electrode 6 can be prevented from bending along with the positive electrode tab 15.

[0037] In this embodiment, the position of the lower end 21h of the first protective tape 21 is aligned with the position of the lower end 23h of the second protective tape 23. With this configuration, bending points of the positive electrode tab 15 are less likely to occur in positions adjacent to the negative electrode 6, and damage to the negative electrode 6 can be suppressed.

[0038] In this embodiment, the upper end 21k of the first protective tape 21 is located above the upper end 5k of the positive electrode current collector 5a. The upper end 23k of the second protective tape 23 is located above the upper end 5k of the positive electrode current collector 5a. The upper end 23k of the second protective tape 23 is located between the upper end 21k of the first protective tape 21 and the upper end 5k of the positive electrode current collector 5a. The dimension of the second protective tape 23 in the up-down direction VD is smaller than the dimension of the first protective tape 21 in the up-down direction VD. The difference D1 between the dimension of the first protective tape 21 and the dimension of the second protective tape 23 in the up-down direction VD is, for example, 1.0 mm to 3.0 mm.

[0039] The upper end 23k of the second protective tape 23 is located above the upper end 6k of the negative electrode 6. Because the rigidity of the positive electrode tab 15 can be reinforced in the area where the second protective tape 23 is provided, when the positive electrode tab 15 is bent, a bending point is formed above the upper end 23k of the second protective tape 23. In other words, a bending point is formed in the positive electrode tab 15 at a position above the upper end 6k of the negative electrode 6. As a result, it is easier to prevent the negative electrode 6 from bending together with the positive electrode tab 15.

[0040] The lower end 23h of the second protective tape 23 is located below the upper end 5k of the positive electrode current collector 5a. This positional relationship causes the second protective tape 23 and the positive electrode current collector 5a to overlap. The second protective tape 23 can also reinforce the rigidity of the positive electrode tab 15 near the upper end 5k of the positive electrode current collector 5a, preventing a bending point from being formed near the upper end 5k of the positive electrode current collector 5a.

[0041] In the vertical direction VD, the distance t1 between the upper end 23k of the second protective tape 23 and the upper end 6k of the negative electrode 6 is, for example, 0.5 mm to 2.0 mm. Ensuring an appropriate distance t1 increases the effect of preventing the negative electrode 6 from bending together with the positive electrode tab 15.

[0042] In the direction parallel to the longitudinal direction of the positive electrode 5, the first protective tape 21 and the second protective tape 23 are contained within the range in which the exposed portion W is provided. With this configuration, it is possible to prevent the first protective tape 21 and the second protective tape 23 from overlapping the positive electrode active material layer 5b.

[0043] The battery 100 further includes a third protective tape 25 that covers the exposed portion W of the positive electrode current collector 5a. When the positive electrode 5 is viewed from above, the first protective tape 21 overlaps the third protective tape 25. The third protective tape 25 can protect the exposed portion W of the positive electrode current collector 5a.

[0044] The third protective tape 25 has a rectangular shape in a plan view and covers the entire exposed portion W. A portion of the third protective tape 25 protrudes upward from the positive electrode 5. In the vertical direction VD, the upper end 25k of the third protective tape 25 is located between the upper end 23k of the second protective tape 23 and the upper end 5k of the positive electrode 5.

[0045] The first protective tape 21, the second protective tape 23, and the third protective tape 25 are made of materials with excellent chemical resistance, insulating properties, and processability. These protective tapes are desirably thin to avoid increasing the volume they occupy in the electrode group 4. The first protective tape 21, the second protective tape 23, and the third protective tape 25 may contain a resin film. Examples of resin films include those with excellent insulating properties, such as polyimide film. There are not necessarily many options for resin films that can be used as protective tapes. Therefore, it is difficult to achieve the desired effects simply by improving the material, thickness, etc. of the first protective tape 21.

[0046] The first protective tape 21 and the second protective tape 23 may be made of resin films of the same type and thickness, which can reduce material costs. For the same reason, the third protective tape 25 may be made of resin films of the same type and thickness.

[0047] 4 is a diagram illustrating the operation of the battery 100 of this embodiment. In FIG. 4, when the positive electrode tab 15 is bent, the positive electrode tab 15 has a bending point P at a position above the upper end 6k of the negative electrode 6. The upper end 21k of the first protective tape 21 is located above the bending point P. The upper end 23k of the second protective tape 23 is located below the bending point P.

[0048] The rigidity of the portion where the second protective tape 23 is present is higher than the rigidity of the portion where the second protective tape 23 is not present. Therefore, when the positive electrode tab 15 is bent, a bending point P is unlikely to be formed below the upper end 23k of the second protective tape 23. In other words, according to this embodiment, the position where the bending point P is formed can be controlled to be within the range from the upper end 23k of the second protective tape 23 to the upper end 21k of the first protective tape 21.

[0049] Fig. 5A is a diagram illustrating the function of the structure of the reference example. Fig. 5B is another diagram illustrating the function of the structure of the reference example. The structure shown in Figs. 5A and 5B is obtained by removing the second protective tape 23 from the battery 100 of this embodiment and moving the first protective tape 21 upward. The separator is omitted in Figs. 5A and 5B.

[0050] 5A and 5B, although the first protective tape 121 is present, the position of the bending point P is unstable when the positive electrode tab 115 is bent due to insufficient rigidity of the positive electrode tab 115. That is, as shown in FIGS. 5A and 5B, the bending point P of the positive electrode tab 115 is formed at a position overlapping the negative electrode 6. As a result, the negative electrode 6 is deformed and damaged.

[0051] FIG. 6 is a plan view of a positive electrode according to a modified example. In the positive electrode 50 according to the modified example, the positive electrode tabs 15 are connected to each of a plurality of positions along the longitudinal direction of the positive electrode 50. Therefore, the battery 100 of this embodiment may include a plurality of positive electrode tabs 15. When the positive electrode 50 and the negative electrode 6 are wound into a cylindrical shape, the plurality of positive electrode tabs 15 can be arranged along the circumferential direction of the cylindrical electrode group 4. This configuration can reduce the internal resistance of the battery 100. The structure of this modified example is useful when the battery 100 has a large diameter.

[0052] The battery of the present disclosure is not limited to a cylindrical battery. Other shapes, such as a rectangular shape or a laminated shape, may also be adopted for the battery of the present disclosure. For example, even in a laminated battery in which positive electrodes and negative electrodes are alternately stacked, the tabs may be bent when bundling multiple tabs, which can cause the same problems as cylindrical batteries.

[0053] The technology of the present disclosure is applicable to stacked batteries or prismatic batteries, but is particularly useful for cylindrical batteries. For example, if the battery 100 of this embodiment is a cylindrical battery with a diameter of 46 mm, the positive electrode tab 15 needs to be bent with a small curvature. In this case, the technology of the present disclosure is particularly useful.

[0054] The battery of the present disclosure is not limited to a lithium secondary battery, but may be other batteries such as a sodium secondary battery or a magnesium secondary battery.

[0055] (Other embodiments) (Addendum) The above description of the embodiments discloses the following techniques.

[0056] (Technology 1) a first electrode including a current collector; a second electrode facing the first electrode; a tab connected to the first electrode so as to protrude from the first electrode; a first protective tape attached to the tab; a second protective tape disposed in a position overlapping the first protective tape; Equipped with a direction along the longitudinal direction of the tab is defined as a vertical direction, a side where a connection portion between the first electrode and the tab is located is defined as a lower side, and a side where a tip end portion of the tab protruding from the first electrode is located is defined as an upper side, a lower end of the first protective tape is located below an upper end of the current collector, and thereby the first protective tape and the current collector overlap, an upper end of the first protective tape is located higher than an upper end of the second electrode in the vertical direction; battery.

[0057] According to the technique of the present disclosure, it is possible to prevent adjacent electrodes from bending together with the tab.

[0058] (Technology 2) The battery according to Technology 1, wherein the lower end of the first protective tape is aligned with the lower end of the second protective tape. With this configuration, bending points of the tabs are less likely to occur in positions adjacent to the second electrode, and damage to the second electrode can be suppressed.

[0059] (Technology 3) The battery according to Technique 1 or 2, wherein the upper end of the second protective tape is located above the upper end of the second electrode. This configuration makes it easier to prevent the second electrode from bending together with the tab.

[0060] (Technology 4) The battery according to any one of techniques 1 to 3, wherein a lower end of the second protective tape is located below an upper end of the current collector. With this configuration, it is possible to avoid formation of a bending point near the upper end of the current collector.

[0061] (Technology 5) The battery according to any one of Techniques 1 to 4, wherein the tab has a bending point at a position above an upper end of the second electrode, the upper end of the first protective tape is located above the bending point, and the upper end of the second protective tape is located below the bending point. According to the technique of the present disclosure, the position at which the bending point is formed can be controlled within a range from the upper end of the second protective tape to the upper end of the first protective tape.

[0062] (Technology 6) The battery according to any one of techniques 1 to 5, wherein the current collector includes an exposed portion on which no active material layer is provided, and the battery further includes a third protective tape covering the exposed portion, and the first protective tape overlaps the third protective tape. The third protective tape can protect the exposed portion of the current collector.

[0063] (Technology 7) The battery according to any one of techniques 1 to 6, wherein the first electrode and the second electrode are wound into a cylindrical shape, and the tabs are connected to each of a plurality of positions along the longitudinal direction of the first electrode. With this configuration, the internal resistance of the battery can be reduced.

[0064] (Technology 8) The battery according to any one of techniques 1 to 7, wherein the battery is a cylindrical battery. The technology of the present disclosure is particularly useful for cylindrical batteries.

[0065] (Technology 9) The battery according to any one of claims 1 to 8, wherein the first electrode is a positive electrode and the second electrode is a negative electrode. When the battery is a cylindrical battery with a standard diameter of 46 mm, the tab needs to be bent with a small curvature. In such a case, the technology of the present disclosure is particularly useful. [Industrial Applicability]

[0066] The technology of the present disclosure is useful for non-aqueous electrolyte secondary batteries such as lithium secondary batteries. [Explanation of symbols]

[0067] 1 container 2 Sealing plate 3 Insulating packing 4 electrode groups 5,50 positive electrode 5a Positive electrode current collector 5b Cathode active material layer 5k,6k,21k,23k,25k upper end 21h,23h bottom end 6 negative electrode 6a Negative current collector 6b Negative electrode active material layer 7 Separator 8 Insulation ring 15 Positive electrode tab 16 Negative electrode tab 21 First protective tape 23 Second protective tape 25 Third protective tape 100 batteries W Exposed part P bending point

Claims

1. a first electrode including a current collector; a second electrode facing the first electrode; a tab connected to the first electrode so as to protrude from the first electrode; a first protective tape attached to the tab; a second protective tape disposed at a position overlapping the first protective tape; Equipped with a direction along the longitudinal direction of the tab is defined as a vertical direction, a side where a connection portion between the first electrode and the tab is located is defined as a lower side, and a side where a tip end portion of the tab protruding from the first electrode is located is defined as an upper side, a lower end of the first protective tape is located below an upper end of the current collector, and thereby the first protective tape and the current collector overlap, an upper end of the first protective tape is located higher than an upper end of the second electrode in the vertical direction; battery.

2. The position of the lower end of the first protective tape is aligned with the position of the lower end of the second protective tape. The battery of claim 1 .

3. an upper end of the second protective tape is located above an upper end of the second electrode; The battery of claim 1 .

4. The lower end of the second protective tape is located below the upper end of the current collector. The battery of claim 1 .

5. the tab has a bent point at a position higher than an upper end of the second electrode; an upper end of the first protective tape is located above the bending point; an upper end of the second protective tape is located below the bending point; The battery of claim 1 .

6. the current collector includes an exposed portion on which no active material layer is provided, the battery further includes a third protective tape covering the exposed portion; the first protective tape overlaps the third protective tape; The battery of claim 1 .

7. the first electrode and the second electrode are wound into a cylindrical shape, the tabs are connected to each of a plurality of positions along the longitudinal direction of the first electrode; The battery of claim 1 .

8. The battery is a cylindrical battery. The battery of claim 1 .

9. the first electrode is a positive electrode, The second electrode is a negative electrode. The battery of claim 1 .

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