Cylindrical battery and manufacturing method thereof

Abstract

Provided is a cylindrical battery in which the connection between a current collector and a core body is stabilized while suppressing damage to an electrode body. In the cylindrical battery 10, a negative electrode 12 has a core body and a mixture layer 12b laminated on at least a portion of the surface of the core body, and has a protrusion part 12a in which the core body protrudes from one end face of an electrode body 14 in a winding axis direction; the protrusion part 12a includes a welded region disposed, in a substantially constant width, along the radial direction of the electrode body, and a non-welded region adjacent to the welded region; the protrusion part in the welded region has, at both ends in the width direction, projections projecting from a central portion; the projections project from the protrusion part in the non-welded region; the protrusion part 12a in the welded region is welded to a lower current collector 17; and the lower current collector 17 is connected to an outer can 15.

Description

[Technical Field]

[0001] The present disclosure relates to cylindrical batteries and methods for manufacturing cylindrical batteries. [Background technology]

[0002] A conventional cylindrical battery is described in Patent Document 1. In this cylindrical battery, an electrode core protrudes from the axial end of the electrode assembly, and the protruding core is laser-welded to the current collector plate. The current collector plate has a convex pressing surface on the side facing the core, and the pressing surface is pressed against the core more strongly than the surrounding area, thereby increasing the contact area between the current collector plate and the core. In this way, a wide longitudinal area of ​​the elongated electrode is electrically connected to the current collector plate, reducing the electrical resistance between the electrode and the current collector plate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-257851 Summary of the Invention [Problem to be solved by the invention]

[0004] However, as a result of intensive research by the inventors, it was found that even if the current collector plate has a pressing surface, if the current collector plate is pressed too hard against the core body, peeling may occur at the edge of the mixture layer, and if the current collector plate is pressed too lightly against the core body, the contact between the current collector plate and the core body becomes unstable, and welding may not be uniform. The technology described in Patent Document 1 is insufficient to stabilize the connection between the current collector plate and the core body while suppressing damage to the electrode body, and there is still room for improvement.

[0005] Therefore, an object of the present disclosure is to provide a cylindrical battery in which the connection between the current collector plate and the core body is stabilized while suppressing damage to the electrode body. [Means for solving the problem]

[0006] A cylindrical battery according to one aspect of the present disclosure includes an electrode assembly in which first and second electrodes of opposite polarity are wound with a separator interposed therebetween, a non-aqueous electrolyte, a cylindrical outer can with a bottom that houses the electrode assembly and the non-aqueous electrolyte, and a sealing body that closes the opening of the outer can, wherein the first electrode has a core and a mixture layer laminated on at least a portion of the surface of the core, and the core has a protrusion that protrudes from one end face of the electrode assembly in the winding axis direction, the protrusion including a welded region that is arranged with a substantially constant width along the radial direction of the electrode assembly and a non-welded region adjacent to the welded region, the protrusion in the welded region having protrusions at both ends in the width direction that protrude relative to the central portion, the protrusions protruding relative to the protrusions in the non-welded region, the protrusions in the welded region being welded to a current collector plate, and the current collector plate being connected to the outer can or the sealing body.

[0007] A manufacturing method for a cylindrical battery according to one aspect of the present disclosure includes an electrode assembly in which first and second electrodes of opposite polarity are wound with a separator interposed therebetween, a non-aqueous electrolyte, a cylindrical outer can with a bottom that houses the electrode assembly and the non-aqueous electrolyte, and a sealing body that closes the opening of the outer can, wherein the first electrode has a core and a mixture layer laminated on at least a portion of the surface of the core, and the core has a protrusion that protrudes from one end face in the winding axis direction of the electrode assembly, and is characterized by including the steps of folding the protrusion radially inward of the electrode assembly to form welding regions having protrusions that protrude from the center at both ends in a width direction perpendicular to the radial direction of the electrode assembly, and a non-welded region in which the protrusions are positioned closer to the center in the winding axis direction of the electrode assembly than the protrusions, welding the protrusions in the welding regions to a current collector plate, and connecting the current collector plate to the outer can or the sealing body. [Effects of the Invention]

[0008] According to the cylindrical battery according to the present disclosure, the connection between the current collector plate and the core body can be stabilized while suppressing damage to the electrode body. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 1 is an axial cross-sectional view of a cylindrical battery according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a perspective view illustrating the structure of an electrode body. [Figure 3] FIG. 4 is a plan view of the lower current collecting plate as viewed from above in the axial direction. [Figure 4] FIG. 2 is a plan view of the electrode body as viewed from below before the lower current collecting plate is welded. [Figure 5A] FIG. 5 is a cross-sectional view taken along line AA in FIG. [Figure 5B] FIG. 5B is a view corresponding to FIG. 5A, showing the electrode body after the current collector plate has been welded. [Figure 6A] 10A and 10B are diagrams illustrating a method for forming a non-welded region. [Figure 6B] 10A to 10C are diagrams illustrating a method for forming a welded portion. [Figure 6C] FIG. 2 is a plan view of an end face of an electrode body having welded and non-welded regions formed thereon. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of a cylindrical battery according to the present disclosure will be described in detail with reference to the drawings. The cylindrical battery according to the present disclosure may be a primary battery or a secondary battery. It may also be a battery using an aqueous electrolyte or a battery using a non-aqueous electrolyte. In the following, a non-aqueous electrolyte secondary battery (lithium ion battery) using a non-aqueous electrolyte will be exemplified as a cylindrical battery 10 according to one embodiment, but the cylindrical battery according to the present disclosure is not limited thereto.

[0011] When multiple embodiments and variations are included below, it is anticipated from the beginning that new embodiments can be constructed by appropriately combining their characteristic features. In the following embodiments, the same components are designated by the same reference numerals in the drawings, and redundant explanations are omitted. Furthermore, multiple drawings include schematic diagrams, and the dimensional ratios of the length, width, height, etc. of each component between different drawings do not necessarily match. For convenience of explanation, in this specification, the side of the sealing body 16 in the axial direction (height direction) of the cylindrical battery 10 is referred to as "upper," and the side of the bottom plate of the outer casing 15 in the axial direction is referred to as "lower." Among the components described below, components not recited in the independent claims representing the highest concepts are optional components and not essential components.

[0012] <Configuration of Cylindrical Battery of One Embodiment> Fig. 1 is an axial cross-sectional view of a cylindrical battery 10 according to one embodiment of the present disclosure, and Fig. 2 is a perspective view illustrating the structure of an electrode assembly 14. As shown in Fig. 1, the cylindrical battery 10 includes a wound electrode assembly 14, a non-aqueous electrolyte (not shown), a cylindrical metal outer can 15 with a bottom that houses the electrode assembly 14 and the non-aqueous electrolyte, and a sealing body 16 that closes the opening of the outer can 15.

[0013] As shown in FIG. 2 , the electrode assembly 14 has a wound structure in which an elongated positive electrode 11 and an elongated negative electrode 12 are wound with two elongated separators 13 interposed therebetween. The positive electrode 11 protrudes upward relative to the negative electrode 12 and the separator 13, and the negative electrode 12 protrudes downward relative to the positive electrode 11 and the separator 13. The positive electrode 11 has a positive electrode protruding portion 11a, where the positive electrode core is exposed and where the positive electrode mixture layer 11b is not provided, at an upper end in the axial direction from the winding start end to the winding end end of the elongated positive electrode 11. The negative electrode 12 has a negative electrode protruding portion 12a, where the negative electrode core is exposed and where the negative electrode mixture layer 12b is not provided, at a lower end in the axial direction from the winding start end to the winding end end of the elongated negative electrode 12. Therefore, the upper end of the electrode body 14 in the axial direction is formed by the positive electrode protruding portion 11a, and the lower end of the electrode body 14 in the axial direction is formed by the negative electrode protruding portion 12a.

[0014] The non-aqueous electrolyte includes a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. Examples of the non-aqueous solvent include esters, ethers, nitriles, amides, and mixtures of two or more of these. The non-aqueous solvent may contain a halogen-substituted compound in which at least a portion of the hydrogen atoms of these solvents are substituted with halogen atoms such as fluorine. The non-aqueous electrolyte is not limited to a liquid electrolyte, but may also be a solid electrolyte using a gel polymer or the like. The electrolyte salt is a lithium salt such as LiPF6.

[0015] The positive electrode 11 has a positive electrode core and a positive electrode mixture layer 11b formed on both sides of the positive electrode core. The positive electrode core can be made of a metal foil, such as aluminum or an aluminum alloy, that is stable within the potential range of the positive electrode 11, or a film with such a metal disposed on the surface. The positive electrode mixture layer 11b contains a positive electrode active material, a conductive agent, and a binder. 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 core, drying the coating, and then compressing it to form the positive electrode mixture layer 11b on both sides of the positive electrode core. The positive electrode mixture layer 11b may be formed on only one side of the positive electrode core.

[0016] The positive electrode active material is mainly composed of a lithium-containing metal composite oxide. Examples of metal elements contained in the lithium-containing metal composite oxide include Ni, Co, Mn, Al, B, Mg, Ti, V, Cr, Fe, Cu, Zn, Ga, Sr, Zr, Nb, In, Sn, Ta, and W. An example of a preferred lithium-containing metal composite oxide is a composite oxide containing at least one of Ni, Co, Mn, and Al.

[0017] Examples of the conductive agent contained in the positive electrode mixture layer 11b include carbon materials such as carbon black, acetylene black, ketjen black, and graphite. Examples of the binder contained in the positive electrode mixture layer 11b include fluororesins such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), polyimide resin, acrylic resin, and polyolefin resin. These resins may be used in combination with cellulose derivatives such as carboxymethyl cellulose (CMC) or its salts, and polyethylene oxide (PEO).

[0018] The negative electrode 12 has a negative electrode core and negative electrode mixture layers 12b formed on both sides of the negative electrode core. The negative electrode core can be made of a metal foil, such as copper or a copper alloy, that is stable within the potential range of the negative electrode 12, or a film with such a metal disposed on the surface. The negative electrode mixture layer 12b contains a negative electrode active material and a binder. The negative electrode 12 can be produced, for example, by applying a negative electrode mixture slurry containing a negative electrode active material and a binder to the negative electrode core, drying the coating, and then compressing it to form the negative electrode mixture layers 12b on both sides of the negative electrode core. Note that the negative electrode mixture layer 12b may be formed on only one side of the negative electrode core.

[0019] The negative electrode active material generally uses a carbon material that reversibly absorbs and releases lithium ions. Preferred carbon materials include natural graphite, such as flake graphite, lump graphite, and amorphous graphite, and artificial graphite, such as lump artificial graphite and graphitized mesophase carbon microbeads. The negative electrode mixture layer 12b may contain a silicon (Si) material as the negative electrode active material. The negative electrode active material may also include a metal other than Si that alloys with lithium, an alloy containing such a metal, or a compound containing such a metal.

[0020] The binder contained in the negative electrode mixture layer 12b may be a fluororesin, PAN, polyimide resin, acrylic resin, polyolefin resin, or the like, as in the case of the positive electrode 11. Preferably, styrene-butadiene rubber (SBR) or a modified product thereof is used. The negative electrode mixture layer 12b may contain, in addition to SBR, for example, CMC or a salt thereof, polyacrylic acid (PAA) or a salt thereof, polyvinyl alcohol, or the like.

[0021] 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. Preferred materials for the separator 13 include polyolefin resins such as polyethylene and polypropylene, and cellulose. The separator 13 may have either a single-layer structure or a laminated structure. A heat-resistant layer or the like may be formed on the surface of the separator 13.

[0022] As shown in Fig. 1, the cylindrical battery 10 has a lower current collector plate (negative electrode current collector plate) 17 made of a metal such as nickel or a nickel alloy, located axially outward (lower) than the electrode body 14. A negative electrode projection 12a projecting from the electrode body 14 is joined to the lower current collector plate 17, which is joined to the inner surface of the bottom plate of an outer can 15. The outer can 15 to which the negative electrode projection 12a is electrically connected via the lower current collector plate 17 serves as a negative electrode terminal. The axial length of the negative electrode projection 12a is, for example, 2 mm to 20 mm.

[0023] Cylindrical battery 10 has an upper current collector plate (positive electrode current collector plate) 18 made of a metal such as aluminum or an aluminum alloy, located axially outward (above) of electrode body 14, and an annular insulating plate 19 located axially above it. In this embodiment, upper current collector plate 18 has the same shape as lower current collector plate 17.

[0024] The cylindrical battery 10 further includes a sealing body 16 and a connection lead 20 made of a metal such as aluminum or an aluminum alloy. The lower end of the connection lead 20 is joined by welding or the like to the upper surface of the upper current collecting plate 18. The connection lead 20 passes through a through-hole in the insulating plate 19 and extends toward the sealing body 16, and the upper end of the connection lead 20 is connected by welding or the like to the lower surface of a filter 22 of the sealing body 16. A cap 26 that forms the top plate of the sealing body 16 is electrically connected to the filter 22, and the cap 26 serves as the positive electrode terminal.

[0025] The cylindrical battery 10 further includes a resin gasket 27 disposed between the outer can 15 and the sealing body 16. The gasket 27 is sandwiched between the outer can 15 and the sealing body 16, and insulates the sealing body 16 from the outer can 15. The gasket 27 serves as a sealant to maintain airtightness inside the battery and as an insulating material to insulate the outer can 15 from the sealing body 16. The outer can 15 has an annular grooved portion 21 along part of its axial direction.

[0026] The grooved portion 21 can be formed, for example, by spinning a portion of the side surface radially inward to create a recess radially inward. The outer can 15 has a bottomed tubular portion including the grooved portion 21 and an annular shoulder portion. The bottomed tubular portion houses the electrode assembly 14 and nonaqueous electrolyte, and the shoulder portion is bent radially inward from the end of the open side of the bottomed tubular portion and extends inward. The shoulder portion is formed when the upper end of the outer can 15 is bent inward and crimped onto the peripheral edge of the sealing body 16. The sealing body 16 is crimped and fixed to the outer can 15 with a gasket 27 between the shoulder portion and the grooved portion 21. In this way, the internal space of the cylindrical battery 10 is sealed.

[0027] The sealing body 16 has a structure in which, in order from the electrode body 14 side, a filter 22, a lower valve body 23, an insulating member 24, an upper valve body 25, and a cap 26 are stacked. Each member constituting the sealing body 16 has, for example, a disk or ring shape, and each member except for the insulating member 24 is electrically connected to one another. The filter 22 has at least one through-hole. The lower valve body 23 and the upper valve body 25 are connected at their respective centers, with the insulating member 24 interposed between their respective peripheral edges.

[0028] If the cylindrical battery 10 generates abnormal heat and the internal pressure of the cylindrical battery 10 rises, the lower valve body 23 deforms and pushes the upper valve body 25 toward the cap 26, causing it to break, cutting off the current path between the lower valve body 23 and the upper valve body 25. If the internal pressure rises further, the upper valve body 25 breaks, causing gas to be discharged from the through-hole 26a of the cap 26. This gas discharge prevents the internal pressure of the cylindrical battery 10 from rising excessively, which could cause the cylindrical battery 10 to explode, thereby improving the safety of the cylindrical battery 10.

[0029] 3 to 6C, the joining of the electrode body 14 and the lower current collector plate 17 at the bottom of the cylindrical battery 10 will be described. Note that the electrode body 14 and the upper current collector plate 18 may also be joined in a similar manner at the top of the cylindrical battery 10.

[0030] FIG. 3 is a plan view of the lower current collector 17 as viewed from above in the axial direction. As shown in FIG. 3, the lower current collector 17 has a shape in which four flat plates extend from the center in a generally cross shape. The lower current collector 17 has bases 17a at both ends in the direction in which the flat plates extend and a protruding ridge 17b protruding upward in the center. The lower current collector 17 is pressed against the negative electrode protrusion 12a constituting the axial lower end of the electrode assembly 14, and a laser beam is applied to a groove provided on the underside of the protrusion 17b, thereby welding the upper surface of the protrusion 17b to the negative electrode protrusion 12a. The material of the lower current collector 17 is not particularly limited as long as it is conductive, but it is preferably the same material as the outer can 15. This facilitates welding between the lower current collector 17 and the outer can 15. The material of the lower current collector 17 and the outer can 15 is, for example, nickel-plated carbon steel.

[0031] FIG. 4 is a plan view of the electrode assembly 14 as viewed from below before the lower current collector plate 17 is welded. A negative electrode projection 12a, from which the negative electrode core projects, is present on the lower end surface of the electrode assembly 14 in the winding axis direction. The negative electrode projection 12a includes a welded region 30 arranged with a substantially constant width along the radial direction of the electrode assembly 14, and a non-welded region 32 adjacent to the welded region 30. The welded region 30 is preferably arranged from the outermost to the innermost circumference of the electrode assembly 14. In this embodiment, as shown in FIG. 4, four welded regions 30 are formed in positions corresponding to the protrusions 17b of the lower current collector plate 17, and four non-welded regions 32 are formed between the welded regions 30. In this manner, the welded regions 30 can be formed in positions corresponding to the protrusions 17b of the lower current collector plate 17. As described below, the welded region 30 and the non-welded region 32 are formed by folding the negative electrode protrusion 12a, which protrudes approximately upright from the end face of the electrode body 14 in the winding axis direction, radially inward of the electrode body 14.

[0032] FIG. 5A is a cross-sectional view taken along line AA in FIG. 4 , showing the cross section of the welded region 30 and the non-welded region 32 before welding the lower current collector plate 17. The negative electrode protrusion 12a in the welded region 30 has protrusions 30b that protrude from the central portion 30a at both ends in the width direction of the welded region 30. This allows excess foil of the negative electrode core, which is generated by folding the negative electrode protrusion 12a in the radial direction of the electrode body 14, to be moved toward the non-welded region 32, stabilizing the folded surface of the central portion 30a. This allows the protrusions 17b of the lower current collector plate 17 to be reliably brought into contact with the central portion 30a in the welded region 30, improving weldability. The width direction of the welded region 30 is perpendicular to the radial direction of the electrode body 14.

[0033] 5A, it is preferable that the width W1 of the welding region 30 and the width W2 of the central portion 30a satisfy the relationship W2 / W1<0.9, which further improves the weldability between the protrusion 17b of the lower current collector plate 17 and the negative electrode projection 12a.

[0034] FIG. 5B is a view corresponding to FIG. 5A of the electrode assembly 14 after welding the lower current collector plate 17. By welding the lower current collector plate 17 while pressing it, the negative electrode protrusion 12a in the welded region 30 is deformed, and the width W3 of the central portion 30a of the welded region 30 becomes narrower than the width W2 of the central portion 30a before welding. That is, the widths W2 and W3 satisfy the relationship W2 > W3. On the other hand, the widths of the protrusions 30b at both ends in the width direction after welding become wider than before welding. The width W3 is, for example, approximately the same as the width of the protrusions 17b of the lower current collector plate 17.

[0035] Next, an example of a method for forming the welded region 30 and the non-welded region 32 will be described with reference to FIGS. 6A to 6C . In this embodiment, first, as shown in FIG. 6A , the non-welded region 32 is formed by folding the negative electrode projection 12 a radially inward of the electrode assembly 14 from four directions. Next, as shown in FIG. 6B , in four regions where the standing negative electrode projection 12 a remains between the non-welded regions 32, the negative electrode projection 12 a is folded radially inward of the electrode assembly 14 to form the welded region 30. For example, when folding the negative electrode projection 12 a in the welded region 30, the amount of bending from the end face of the negative electrode projection 12 a can be adjusted to make the negative electrode projection 12 a in the welded region 30 protrude relative to the negative electrode projection 12 a in the non-welded region 32. As a result, the negative electrode projection 12 a in the non-welded region 32 is positioned closer to the center in the winding axis direction of the electrode assembly 14 than the protrusion 30 b. FIG. 6C is a plan view of the end face of the electrode body 14 on which the welded region 30 and the non-welded region 32 are formed.

[0036] <Action and effect confirmation test> An experimental sample was prepared by folding the negative electrode core protruding from the end of the electrode assembly in the direction of the winding axis, forming a welded region and a non-welded region similar to the example shown in Figure 4. A comparative sample was also prepared in which the negative electrode core protruding from the end of the electrode assembly in the direction of the winding axis was left standing without being folded. A lower current collector plate having a configuration similar to the example shown in Figure 3 was pressed against the experimental sample and comparative sample, and laser welding was performed by irradiating a laser beam from the lower current collector plate side. The load with which the lower current collector plate was pressed against the experimental sample and comparative sample was changed, and five experimental samples and five comparative samples were prepared for each load level, and the weldability and damage to the electrode assembly were evaluated.

[0037] [Weldability evaluation] The welding between the lower current collector plate and the negative electrode core was visually checked to see if it was adequate. If the welding was adequate for all samples, the sample was rated as OK, but if there was one or more samples with insufficient welding, the sample was rated as NG.

[0038] [Evaluation of electrode damage] The cross section of each sample was observed using an X-ray CT scanner (Shimadzu Corporation, SMX-225CT FPD HR), and the condition of the cross-section samples cut from each sample was also checked to see if peeling had occurred at the interface between the negative electrode substrate and the negative electrode mixture layer. If no peeling had occurred in any of the samples, the sample was rated as OK, and if peeling had occurred in one or more samples, the sample was rated as NG.

[0039] The results for the experimental samples are shown in Table 1, and the results for the comparative samples are shown in Table 2. The load ratios in Tables 1 and 2 are the ratios to the load that can be welded when a separately measured comparative sample is used.

[0040] [Table 1]

[0041] [Table 2]

[0042] As shown in Table 1, the experimental samples according to the present disclosure were able to stabilize the connection between the current collector plate and the core body while suppressing damage to the electrode body when the load ratio was in the range of 0.67 to 0.33. On the other hand, the comparative samples were unable to achieve both suppression of damage to the electrode body and good weldability.

[0043] <Modification> The present disclosure is not limited to the above-described embodiment and its variations, and various improvements and modifications are possible within the scope of the claims of the present application and their equivalents. For example, in the above-described embodiment, the cylindrical battery 10 is described as having an upper current collector 18 disposed above the electrode assembly 14 and a lower current collector 17 disposed below the electrode assembly 14. However, the cylindrical battery may have only an upper current collector or only a lower current collector. In this case, the exposed portion of the electrode core on the side where the current collector is not provided may be electrically connected to the sealing member or the outer can using one or more leads joined thereto.

[0044] In the above embodiment, the shapes of the lower current collecting plate 17 and the upper current collecting plate 18 are both cross-shaped, but this is not limited to this example and may be, for example, a disk shape with protrusions. Furthermore, the shape, material, etc. of the upper current collecting plate 18 may be the same as or different from the shape, material, etc. of the lower current collecting plate 17.

[0045] In the above embodiment, the non-welded area 32 is formed first, followed by the welded area 30, but the non-welded area 32 may be formed after the welded area 30 is formed, or the welded area 30 and the non-welded area 32 may be formed simultaneously. [Explanation of symbols]

[0046] 10 Cylindrical battery, 11 Positive electrode, 11a Positive electrode protrusion (protrusion), 12 Negative electrode, 12a Negative electrode protrusion (protrusion), 12b Mixture layer, 13 Separator, 14 Electrode body, 15 Outer can, 16 Sealing body, 17 Lower current collector plate (current collector plate), 17a Base, 17b Protrusion, 18 Upper current collector plate (current collector plate), 19 Insulating plate, 20 Connection lead, 21 Grooved portion, 22 Filter, 23 Lower valve body, 24 Insulating member, 25 Upper valve body, 26 Cap, 26a Through hole, 27 Gasket, 30 Welded area, 30a Center, 30b Protrusion, 32 Non-welded area

Claims

1. A cylindrical battery comprising: an electrode assembly in which a first electrode and a second electrode having opposite polarities are wound with a separator interposed therebetween; a non-aqueous electrolyte; a cylindrical outer can with a bottom that houses the electrode assembly and the non-aqueous electrolyte; and a sealing body that closes an opening of the outer can, the first electrode has a core body and a mixture layer laminated on at least a part of a surface of the core body, and has a protruding portion where the core body protrudes from one end face in the winding axis direction of the electrode body, the protrusion includes a welding region arranged with a substantially constant width along the radial direction of the electrode body, and a non-welding region adjacent to the welding region, The protrusion in the welding region has protrusions at both ends in the width direction that protrude relative to a center portion, the protrusion protrudes relative to the protrusion in the non-welded region; The protrusion of the welding region is welded to a current collecting plate, The cylindrical battery, wherein the current collector plate is connected to the outer can or the sealing body.

2. A method for manufacturing a cylindrical battery comprising: an electrode assembly in which a first electrode and a second electrode having opposite polarities are wound with a separator interposed therebetween; a non-aqueous electrolyte; a cylindrical outer can with a bottom that houses the electrode assembly and the non-aqueous electrolyte; and a sealing body that closes an opening of the outer can, wherein the first electrode has a core and a mixture layer laminated on at least a portion of a surface of the core, and the core has a protruding portion that protrudes from one end face in the winding axis direction of the electrode assembly, folding the protruding portions radially inward of the electrode body to form welding regions having protruding portions protruding from a center portion at both ends in a width direction perpendicular to the radial direction of the electrode body, and a non-welding region in which the protruding portions are positioned closer to the center in the winding axis direction of the electrode body than the protruding portions; welding the protrusion of the welding area to a current collector plate; and connecting the current collector plate to the outer can or the sealing body.

3. 3. The method for manufacturing a cylindrical battery according to claim 2, wherein, before welding the protrusion of the welding region to the current collector plate, the width W1 of the welding region and the width W2 of the central portion satisfy the relationship W2 / W1<0.

9.

4. 4. The method for manufacturing a cylindrical battery according to claim 2 or 3, wherein a width W2 of the central portion before welding the protruding portion of the welding region to the current collector plate and a width W3 of the central portion after welding the protruding portion of the welding region to the current collector plate satisfy the relationship W2 > W3.

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