Cylindrical battery

Abstract

A cylindrical battery according to the present disclosure comprises: a wound electrode body (14) in which a positive electrode plate (11) and a negative electrode plate (12) are wound with a separator (13) therebetween, the wound electrode body (14) having a cylindrical hollow section (23) in the winding center; a cylindrical outer packaging can (16) that accommodates the electrode body (14); and a sealing body (17) that blocks the opening of the outer packaging can (16). The cylindrical battery includes a lead (20) that is connected to the electrode plates forming the electrode body (14), and comprises current collection members (30) that are connected to the lead (20) and the sealing body (17) and are disposed between the electrode body (14) and the sealing body (17). The current collection members (30) are characterized in that a current collection member (30) on the electrode body (14) side and a current collection member (30) on the sealing body (17) side are disposed so as to cover the hollow section (23).

Description

Cylindrical battery

[0001] The present disclosure relates to cylindrical batteries, and more particularly to the internal structure of cylindrical batteries.

[0002] A cylindrical battery generally has a structure including a wound electrode assembly in which a positive electrode and a negative electrode are spirally wound with a separator interposed therebetween, a cylindrical outer can with a bottom that houses the electrode assembly, and a sealing member that closes the opening of the outer can, with leads extending from the electrode assembly connected to the sealing member (see, for example, Patent Document 1). In addition, a cylindrical hollow portion is formed in the center of the electrode assembly.

[0003] Japanese Patent Application Laid-Open No. 2005-285514

[0004] When abnormal heat is generated in the electrode body, the hollow portion has the highest flame temperature and flame density, so the sealing member located on the top plate thereof may be directly hit by the flame and melt, creating a hole, which allows the flame to radiate from the hole. Note that even the cylindrical battery described in Prior Art 1 cannot solve this problem.

[0005] The cylindrical battery according to the present disclosure includes a wound electrode assembly in which positive and negative electrode plates are wound with a separator interposed therebetween, the wound electrode assembly having a cylindrical hollow portion at the center of the winding, a cylindrical outer can housing the electrode assembly, and a sealing body that closes the opening of the outer can. The cylindrical battery includes a current collecting member that includes leads connected to the electrode plates that constitute the electrode assembly, is connected to the leads and the sealing body, and is disposed between the electrode assembly and the sealing body. The current collecting member is characterized in that the current collecting member on the electrode assembly side and the current collecting member on the sealing body side are disposed so as to cover the hollow portion.

[0006] According to the cylindrical battery of the present disclosure, when the battery generates abnormal heat, it is possible to prevent flames from the hollow portion of the electrode body from directly striking the sealing body.

[0007] 1 is a cross-sectional view of a cylindrical battery according to an embodiment of the present invention, and FIG. 2 is a perspective view of the upper part of the cylindrical battery according to an embodiment of the present invention, showing the state before the sealing body is crimped and fixed.

[0008] Hereinafter, an example of an embodiment of a cylindrical battery according to the present disclosure will be described in detail with reference to the drawings. Note that configurations obtained by selectively combining the components of multiple embodiments and variations described below are included within the scope of the present disclosure.

[0009] Fig. 1 is a cross-sectional view of a cylindrical battery 10 according to an embodiment. As shown in Fig. 1, the cylindrical battery 10 includes a wound electrode assembly 14, an electrolyte, a cylindrical outer can 16 with a bottom that houses the electrode assembly 14 and the electrolyte, and a sealing member 17 that closes the opening of the outer can 16. The electrode assembly 14 includes a positive electrode 11, a negative electrode 12, and a separator 13, and has a wound structure in which the positive electrode 11 and the negative electrode 12 are spirally wound with the separator 13 interposed therebetween. Hereinafter, for convenience of explanation, the sealing member 17 side of the battery will be referred to as the top, and the bottom side of the outer can 16 will be referred to as the bottom.

[0010] The positive electrode 11, negative electrode 12, and separator 13 that constitute the electrode assembly 14 are all long, strip-like bodies that are spirally wound and alternately stacked in the radial direction of the electrode assembly 14. The negative electrode 12 is formed to be slightly larger than the positive electrode 11 in order to prevent lithium precipitation. That is, the negative electrode 12 is formed to be longer than the positive electrode 11 in the longitudinal and width directions. The separator 13 is formed to be at least slightly larger than the positive electrode 11, and, for example, two separators 13 are arranged to sandwich the positive electrode 11. The electrode assembly 14 has a positive electrode lead 20 connected to the positive electrode 11 by welding or the like, and a negative electrode lead (not shown) connected to the negative electrode 12 by welding or the like.

[0011] As will be described in more detail below, the cylindrical battery 10 includes a plurality of positive electrode leads 20. The cylindrical battery 10 further includes a current collecting member 30 disposed between the electrode body 14 and the sealing body 17. The current collecting member 30 is a conductive member to which the positive electrode leads 20 and the sealing body 17 are connected, and electrically connects the positive electrode leads 20 and the sealing body 17. That is, in this embodiment, the current collecting member 30 functions as a positive electrode current collecting member. Note that a negative electrode lead may be connected to the current collecting member 30, and the current collecting member 30 may also serve as a negative electrode current collecting member.

[0012] The positive electrode 11 has a positive electrode core and a positive electrode mixture layer disposed on the positive electrode core. The positive electrode core can be made of a foil of a metal stable within the potential range of the positive electrode 11, such as aluminum, an aluminum alloy, stainless steel, or titanium, or a film with such a metal disposed on its surface. The positive electrode mixture layer contains a positive electrode active material, a conductive agent, and a binder, and is preferably provided on both sides of the positive electrode core except for the portion to which the positive electrode lead 20 is connected. The positive electrode active material is a lithium transition metal composite oxide containing a transition metal element such as Ni, Co, or Mn.

[0013] The negative electrode 12 has a negative electrode core and a negative electrode mixture layer disposed on the negative electrode core. The negative electrode core can be a foil of a metal stable within the potential range of the negative electrode 12, such as copper, copper alloy, stainless steel, nickel, or nickel alloy, or a film with such a metal disposed on its surface. The negative electrode mixture layer contains a negative electrode active material and a binder, and is preferably provided on both sides of the negative electrode core except for the portion where the negative electrode lead is connected. The negative electrode active material generally uses a carbon material that reversibly absorbs and releases lithium ions. The negative electrode active material may also use an element that alloys with Li, such as Si or Sn, or a material containing such an element.

[0014] A porous sheet having ion permeability and insulating properties is used for the separator 13. Specific examples of the porous sheet include a microporous thin film, a woven fabric, and a nonwoven fabric. Suitable materials for the separator 13 include polyolefins such as polyethylene and polypropylene, and cellulose. The separator 13 may have a single-layer structure or a multi-layer structure. The separator 13 may have, for example, a multi-layer structure including a thermoplastic resin layer such as polyolefin and a cellulose fiber layer, a two-layer structure of polyethylene (PE) / polypropylene (PP), or a three-layer structure of PE / PP / PE.

[0015] The electrolyte may be an aqueous electrolyte, but in this embodiment, a non-aqueous electrolyte is used. The non-aqueous electrolyte has lithium ion conductivity. The non-aqueous electrolyte may be a liquid electrolyte (electrolytic solution) or a solid electrolyte.

[0016] The liquid electrolyte (electrolytic solution) contains 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 mixed solvents of two or more of these. Examples of the non-aqueous solvent include ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and mixed solvents of these. The non-aqueous solvent may contain a halogen-substituted compound (e.g., fluoroethylene carbonate) in which at least a portion of the hydrogen atoms of these solvents are substituted with halogen atoms such as fluorine. Examples of the electrolyte salt include LiPF ６ Lithium salts such as

[0017] As the solid electrolyte, for example, a solid or gel-like polymer electrolyte, an inorganic solid electrolyte, etc. can be used. As the inorganic solid electrolyte, a material known in all-solid-state lithium ion secondary batteries, etc. (for example, an oxide-based solid electrolyte, a sulfide-based solid electrolyte, a halogen-based solid electrolyte, etc.) can be used. The polymer electrolyte includes, for example, a lithium salt and a matrix polymer, or a non-aqueous solvent, a lithium salt, and a matrix polymer. As the matrix polymer, for example, a polymer material that absorbs a non-aqueous solvent and gels is used. As the polymer material, for example, a fluororesin, an acrylic resin, a polyether resin, etc. can be used.

[0018] An insulating plate 18 is disposed on the upper surface of the electrode body 14. In the example shown in FIG. 1 , a positive electrode lead 20 passes through a through hole in the insulating plate 18 and extends toward the sealing body 17. A current collecting member 30 to which a plurality of positive electrode leads 20 are connected is connected to the underside of the sealing body 17 by welding or the like, and the electrically connected sealing body 17 serves as a positive electrode terminal. The negative electrode lead is connected, for example, to the inner surface of the bottom of the outer can 16 by welding or the like, and the outer can 16 serves as a negative electrode terminal. The outer can 16 and the sealing body 17 are connected to an external circuit, for example, other batteries constituting the battery module, a charger, etc.

[0019] The outer can 16 is a cylindrical metal container with a bottom that is open on one axial side, and the opening of the outer can 16 is closed by a sealing body 17. A gasket 22 is provided between the outer can 16 and the sealing body 17 to ensure airtightness inside the battery. The outer can 16 has a grooved portion 21 that protrudes inward from a portion of its side surface and supports the sealing body 17. The grooved portion 21 is preferably formed in an annular shape along the circumferential direction of the outer can 16, and supports the sealing body 17 on its top surface. The sealing body 17 is fixed to the top of the outer can 16 by the grooved portion 21 and the open end of the outer can 16 that is crimped to the sealing body 17.

[0020] The sealing body 17 closes the opening of the outer can 16. In the example shown in FIG. 1 , the sealing body 17 is configured as a cap. The sealing body 17 may have a structure in which an internal terminal plate, a lower valve body, an insulating member, an upper valve body, and a cap are stacked in this order from the electrode body 14 side. Each member constituting the sealing body 17 may have, for example, a disk or ring shape, and each member except for the insulating member may be electrically connected to each other. Alternatively, the lower valve body and the upper valve body may be connected at their respective centers, with an insulating member interposed between their respective peripheral edges.

[0021] The positive electrode lead 20 and the current collecting member 30 will be described in detail below with further reference to Fig. 2. Fig. 2 is a perspective view of the upper part of the cylindrical battery 10, showing the state before the opening of the outer can 16 is sealed with the sealing body 17.

[0022] 1 and 2 , the electrode body 14 includes a plurality of positive electrode leads 20 connected to the positive electrode 11. The plurality of positive electrode leads 20 extend from the upper end of the electrode group 14a constituting the electrode body 14 toward the sealing body 17 and are connected to a current collecting member 30 arranged on an insulating plate 18. The electrode group 14a refers to a wound body made up of the positive electrode 11, the negative electrode 12, and the separator 13, and a hollow portion 23 is formed in the winding core of the electrode group 14a.

[0023] The hollow portion 23 is a space extending in the axial direction of the electrode group 14a. The current collecting member 30 is a conductive member connected to the sealing body 17, and the positive electrode lead 20 is electrically connected to the sealing body 17 via the current collecting member 30. In this embodiment, the outer can 16 in which the grooved portion 21 is formed functions as a negative electrode terminal, and therefore the current collecting member 30 is arranged so as not to come into contact with the grooved portion 21.

[0024] The positive electrode lead 20 is a rectangular conductive member, and is made of, for example, a metal containing aluminum as a main component. The material constituting the positive electrode lead 20 is preferably an aluminum alloy. The aluminum alloy is an alloy to which one or more other metal elements, such as copper, manganese, silicon, magnesium, zinc, or nickel, are added, and the electrical resistance, hardness, etc. of the material can be changed by adjusting the type and amount of the added element.

[0025] The width and thickness of the positive electrode lead 20 vary depending on the size, capacity, etc. of the battery, but an example of the width of the positive electrode lead 20 is 2 mm or more and 15 mm or less, or 3 mm or more and 10 mm or less. An example of the thickness of the positive electrode lead 20 is 0.03 mm or more and 0.15 mm or less, or 0.05 mm or more and 0.10 mm or less. The multiple positive electrode leads 20 may have different widths and thicknesses from one another, but in the example shown in FIG. 2 , all of the positive electrode leads 20 have substantially the same width and thickness.

[0026] The positive electrode lead 20 is welded to the core of the positive electrode 11. The positive electrode 11 has a plurality of core exposed portions spaced apart in the longitudinal direction of the positive electrode 11, where the positive electrode mixture layer is not present on the positive electrode core and the surface of the positive electrode core is exposed. One positive electrode lead 20 is connected to each exposed portion by welding or the like. The positive electrode lead 20 is generally joined to only one side of the positive electrode core, but the core exposed portions are provided on both sides of the positive electrode 11. The core exposed portions are formed, for example, to have substantially the same size so as to overlap in the thickness direction of the positive electrode 11. The welding position of the positive electrode lead 20 at each exposed portion is not particularly limited, and the positive electrode lead 20 is arranged within the range of the core exposed portion so as not to overlap with the positive electrode mixture layer.

[0027] In the embodiment illustrated in Fig. 2, three positive electrode leads 20 are provided, and thus core exposed portions are formed at three locations spaced apart in the longitudinal direction of the positive electrode 11. The spacing between each exposed portion may be constant or may vary. For example, the layout of the positive electrode leads 20 is appropriately set depending on the battery performance of the cylindrical battery 10, such as the capacity and output characteristics. Therefore, the spacing between each core exposed portion is determined depending on the layout, etc. The number of positive electrode leads 20 may be one, but is preferably multiple for large batteries, and may be, for example, 2 to 15.

[0028] The current collecting member 30 is a conductive member to which multiple positive electrode leads 20 are welded and which is welded to the sealing body 17. The current collecting member 30 is disposed between the electrode body 14 and the sealing body 17 and functions as a positive electrode current collecting member. There are no particular limitations on the constituent material of the current collecting member 30, but the current collecting member 30 is made of, for example, a metal containing aluminum as a main component, similar to the positive electrode leads 20. One suitable example of a constituent material of the current collecting member 30 is an aluminum alloy. The current collecting member 30 has welds 32 to the sealing body 17 and welds 31 to the positive electrode leads 20 formed thereon.

[0029] The current collecting member 30 is disposed on the electrode body 14 via the insulating plate 18. The current collecting member 30 is disposed on the insulating plate 18, but may be fixed to the insulating plate 18. The insulator interposed between the electrode body 14 and the current collecting member 30 is not limited to the insulating plate 18, and may be, for example, an insulator constituting the electrode body 14 or the current collecting member 30. Examples of insulators other than the insulating plate 18 include the separator 13 constituting the electrode body 14 and an insulating layer provided on the surface of the current collecting member 30 facing the electrode body 14.

[0030] 1 , the current collecting members 30 are arranged so that the current collecting member 30 on the electrode body 14 side and the current collecting member 30 on the sealing body 17 side cover the hollow portion 23 of the electrode body 14. The current collecting members 30 have a width and length greater than the diameter of the hollow portion 23, and are arranged so as to cover, for example, the entire hollow portion 23 and the radially inner portion of the electrode body 14.

[0031] The current collecting member 30 may have a through hole 34 in the portion covering the hollow portion 23. The hollow portion 23 in the electrode body 14 serves as an exhaust path when an abnormality occurs in the battery and gas is generated. Furthermore, by providing the current collecting member 30 with the through hole 34, flames generated in the hollow portion 23 can be dispersed between the current collecting member 30 on the sealing body 17 side and the current collecting member 30 on the electrode body 14 side. This reduces the density of the flame radiating from the hollow portion 23, thereby preventing the battery from exploding.

[0032] The current collecting member 30 is disposed so that at least a portion of the through hole 34 overlaps with the hollow portion 23 in the axial direction of the electrode body 14. In the example shown in Fig. 2, the positive electrode lead 20 is welded to the periphery of the through hole 34 of the current collecting member 30 so as not to cover the through hole 34.

[0033] A plurality of welds 31 are formed on the current collecting member 30 so as to surround the through-hole 34. The positive electrode lead 20 is welded to a first surface (upper surface) of the current collecting member 30 facing the sealing body 17, or to a second surface (lower surface) of the current collecting member 30 facing the electrode body 14, or to both the first and second surfaces. In the example shown in FIG. 2 , all of the positive electrode leads 20 are welded to the upper surface of the current collecting member 30. In this case, good welds 31 can be easily formed, and the reliability of the welds 31 is also improved. The welds 31 may be formed above the hollow portion 23 of the electrode body 14. In this case, the welds 31 can be formed by inserting a jig used for welding into the hollow portion 23.

[0034] The through hole 34 is formed by passing through the current collecting member 30 in the axial direction of the electrode body 14, and has a perfect circular shape in a planar view in the example shown in Fig. 2. A through hole is also formed in the insulating plate 18 at a position overlapping with the through hole 34. In a planar view of the electrode body 14 and the current collecting member 30, the through hole 34 is larger than the hollow portion 23, and the current collecting member 30 may be disposed on the electrode body 14 so that the entire hollow portion 23 is exposed through the through hole 34. The current collecting member 30 is disposed, for example, so that the center of the through hole 34 overlaps with the central axis of the electrode body 14.

[0035] As described above, in the illustrated embodiment, the current collecting member 30 on the electrode body 14 side is provided with the through hole 34 at a position that covers the hollow portion 23 of the electrode body 14, but in the present disclosure, it is also possible to employ a structure that does not include the through hole 34. In other words, the current collecting member 30 on the electrode body 14 side and the sealing body 17 side of the current collecting member 30 can doubly suppress flames that occur in the hollow portion 23 of the electrode body 14.

[0036] The current collecting member 30 has a folded portion 33 near the middle of the current collecting member 30 on the electrode body 14 side and the current collecting member 30 on the sealing body 17 side. The folded portion 33 is formed by bending the metal plate that constitutes the current collecting member 30. The folded portion 33 is formed parallel to the width direction of the current collecting member 30. Note that the folded portion 33 may have a half-cut line, a notch, or the like formed therein. The folded portion 33 is formed in at least one location, but may also have multiple folded portions formed along the length of the current collecting member 30.

[0037] The current collecting member 30 is preferably wider and thicker than the positive electrode lead 20. The current collecting member 30 is, for example, a metal plate having a substantially constant width and thickness over its entire length. The dimensions of the current collecting member 30 can be changed appropriately depending on the size of the cylindrical battery 10, but for example, the width of the current collecting member 30 is 10 mm to 30 mm, or 15 mm to 25 mm. The thickness of the current collecting member 30 is, for example, 0.1 mm to 1.0 mm, or 0.2 mm to 0.5 mm.

[0038] The width of the current collecting member 30 is greater than the thickness. The ratio of the width to the thickness of the current collecting member 30 is preferably 30 to 100 times, more preferably 40 to 90 times, and particularly preferably 50 to 80 times. When at least one of the thickness and width of the current collecting member 30 is not constant, it is sufficient that the ratio of the average width to the average thickness of the current collecting member 30 or the ratio of the maximum width to the maximum thickness of the current collecting member 30 is within the range.

[0039] The width direction cross-sectional area of ​​the current collecting member 30 is larger than the width direction cross-sectional area of ​​the positive electrode lead 20, and is preferably 5 to 100 times the width direction cross-sectional area of ​​the positive electrode lead 20. More preferably, it is 10 to 50 times, and particularly preferably 15 to 30 times. In this case, contact between the outer can 16 and the current collecting member 30 can be suppressed. When the width direction cross-sectional area of ​​at least one of the positive electrode lead 20 and the current collecting member 30 is not constant, it is sufficient that the ratio of the average values ​​or the maximum values ​​of the width direction cross-sectional areas of each member is within the above range. It is preferable to increase the width direction cross-sectional area of ​​the current collecting member 30 by making both the thickness and width larger than those of the positive electrode lead 20.

[0040] The thickness of the current collecting member 30 is, for example, 1.5 to 15 times, and preferably 2 to 10 times, the thickness of the positive electrode lead 20. When the thickness of at least one of the positive electrode lead 20 and the current collecting member 30 is not constant, it is sufficient that the ratio of the average values ​​or the ratio of the maximum values ​​of the thicknesses of each member is within the range (the same applies to the widths). Furthermore, the width of the current collecting member 30 is, for example, 1.5 to 10 times, and preferably 2 to 6 times, the width of the positive electrode lead 20.

[0041] The maximum width of the current collecting member 30 is preferably 30% to 90% of the minimum inner diameter of the outer can 16, more preferably 35% to 80% and particularly preferably 40% to 70%. In this embodiment, the inner diameter of the outer can 16 is smallest at the portion where the grooved portion 21 is formed. If the ratio of the maximum width of the current collecting member 30 to the minimum inner diameter of the outer can 16 is within this range, contact between the outer can 16 and the current collecting member 30 can be suppressed, and welding of the positive electrode lead 20 can also be facilitated.

[0042] The current collecting member 30 is arranged such that a portion where a weld 31 to the positive electrode lead 20 is formed (hereinafter referred to as the "first region") is aligned radially of the electrode body 14 on the insulating plate 18. Furthermore, a portion where a weld 32 to the sealing body 17 is formed (hereinafter referred to as the "second region") is aligned along the underside of the sealing body 17. At least one weld 32 is formed within the second region. In this embodiment, a folded portion 33 forms the boundary between the first region and the second region. The folded portion 33 is arranged radially outward of the outer can 16 relative to one longitudinal end of the current collecting member 30 present in the first region, and is close to the grooved portion 21. In this embodiment, the outer can 16 in which the grooved portion 21 is formed functions as a negative electrode terminal, and therefore the current collecting member 30 is arranged so as not to come into contact with the grooved portion 21.

[0043] The width of the current collecting member 30 may vary along the length direction. In order to prevent contact with the outer can 16 while increasing the width of the current collecting member 30, the width of the current collecting member 30 may be varied so that the width of the portion where the folded portion 33 is formed is smaller than that of the one end portion in the length direction. In other words, the width of the current collecting member 30 may be smaller at the portion where the folded portion 33 is formed than at the one end portion in the length direction on the electrode body 14 side.

[0044] The width of the first region of the current collecting member 30 may gradually decrease from one longitudinal end portion toward the folded-back portion 33, or may decrease in a stepwise manner at one or more locations. The width of the current collecting member 30 at the folded-back portion 33 may be, for example, 90% or less, 30% to 80%, or 50% to 70% of the width at one longitudinal end portion. The width of the second region of the current collecting member 30 may be substantially the same as the width at the folded-back portion 33 over its entire length, or may be wider than the width at the folded-back portion 33.

[0045] The current collecting member 30 is, for example, bent into an L-shape at the fold portion 33, and has an L-shape when no external force is applied. When the sealing body 17 is crimped and fixed to the opening edge portion of the outer can 16, the current collecting member 30 is bent at the fold portion 33 so that the first region and the second region face each other, and is disposed between the electrode body 14 and the sealing body 17 in a state compressed in the axial direction of the electrode body 14. The first region and the second region of the current collecting member 30 may be disposed substantially parallel and face each other with a small gap therebetween, for example, and may sandwich the positive electrode lead 20 welded to the upper surface of the first region.

[0046] As described above, in a cylindrical battery having the above configuration, the current collecting member 30 on the electrode body 14 side and the current collecting member 30 on the sealing body 17 side are arranged so as to cover the hollow portion 23 of the electrode body 14, so that two opposing surfaces of the current collecting member 30 are arranged above the hollow portion 23. This makes it possible to prevent a flame generated in the hollow portion 23 from directly striking the sealing body 17. This prevents holes from being formed in the sealing body 17 and prevents the flame from radiating from the sealing body 17.

[0047] The above-described embodiment may be appropriately modified without departing from the scope of the present disclosure, and may be configured by selectively combining the components of the above-described embodiment. For example, in the configuration illustrated in FIG. 2, the number of positive electrode leads 20 may be six. It is also possible to arrange a plurality of current collecting members 30 between the electrode body 14 and the sealing body 17.

[0048] REFERENCE SIGNS LIST 10 Cylindrical battery, 11 Positive electrode, 12 Negative electrode, 13 Separator, 14 Electrode body, 14a Electrode group, 16 Outer can, 17 Sealing body, 18 Insulating plate, 20 Positive electrode lead, 21 Grooved portion, 22 Gasket, 23 Hollow portion, 30 Current collecting member, 31, 32 Welded portion, 33 Folded portion, 34 Through hole

Claims

1. A cylindrical battery comprising: a wound electrode assembly in which positive and negative electrode plates are wound with a separator interposed therebetween, the wound electrode assembly having a cylindrical hollow portion at the center of the winding; a cylindrical outer can that houses the electrode assembly; and a sealing body that closes the opening of the outer can; the cylindrical battery including leads connected to the electrode plates that make up the electrode assembly; and a current collecting member that is connected to the leads and the sealing body and is positioned between the electrode assembly and the sealing body, the current collecting member being positioned so that the current collecting member on the electrode assembly side and the current collecting member on the sealing body side cover the hollow portion.

2. A cylindrical battery as described in claim 1, wherein the current collecting member has a folded portion at the intermediate portion between the current collecting member on the electrode body side and the current collecting member on the sealing body side, the current collecting member on the electrode body side is connected to the lead, and the current collecting member on the sealing body side is connected to the sealing body.

3. A cylindrical battery according to claim 1 or 2, wherein the current collecting member on the electrode body side has a through hole at a position covering the hollow portion.

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