Cylindrical battery

Abstract

This battery is provided with a bottomed cylindrical exterior can (16) for housing an electrode body (14), the exterior can having: a cylindrical portion including a shoulder portion (38) extending radially inward at an end portion on one side in an axial direction, and a grooved portion (34) recessed radially inward over the entire circumference in a circumferential direction; and a bottom portion closing an opening on another side in the axial direction in the cylindrical portion. The exterior can (16) has a bottomed recessed portion (70) between a first location (K1) overlapping the radially outer end of a sealing body (17) on one side in the axial direction and a second location (K2) located closest to the bottom portion of the grooved portion (34) in the axial direction.

Description

Cylindrical battery

[0001] The present disclosure relates to a cylindrical battery.

[0002] Conventionally, as a cylindrical battery, there is one described in Patent Document 1. This cylindrical battery includes a sealing body having a sealing plate, a metal plate as an internal terminal plate, and an insulating member interposed between the sealing plate and the metal plate. This cylindrical battery seals the inside by caulking and fixing the sealing body through a resin gasket to the opening of a bottomed cylindrical outer can. The sealing plate of this cylindrical battery is provided with an inclined portion that is displaced outward in the axial direction and whose thickness continuously decreases as it goes radially from the inner peripheral portion to the outer peripheral portion. When this cylindrical battery abnormally generates heat due to an internal short circuit or the like and the internal pressure rises, the inclined portion is inverted and the current path inside the battery is cut off. Further, when the internal pressure further rises, the inclined portion breaks and the gas inside the battery is discharged to the outside.

[0003] International Publication No. 2016 / 157749

[0004] There may be a desire to provide a vent mechanism that breaks with an increase in internal pressure on the axial sealing body side. For example, in a vehicle-mounted battery module including a plurality of electrically connected cylindrical batteries, it may be required to provide a vent mechanism on the axial sealing body side in order to prevent the contents (such as high-pressure gas and melt) from being ejected to the sheet side when the internal pressure rises. In such a case, if the vent mechanism can be eliminated from the sealing body and the structure of the sealing body can be simplified, the sealing body can be manufactured easily and with high precision.

[0005] Furthermore, when it is desired to provide a vent mechanism on the axial sealing body side, depending on the structure of the sealing body, it may be difficult to provide a vent mechanism in the sealing body. Therefore, an object of the present disclosure is to provide a cylindrical battery in which the vent mechanism can be eliminated from the sealing body and the contents can be ejected from the axial sealing body side when the internal pressure rises.

[0006] To solve the above problems, the cylindrical battery according to the present disclosure comprises an electrode body in which a positive electrode and a negative electrode are wound with a separator between them; a cylindrical portion including a shoulder portion extending radially inward at one end in the axial direction and a groove portion recessed radially inward along the entire circumference in the circumferential direction; a bottomed cylindrical outer can for housing the electrode body, the outer can having a bottom portion that closes the opening on the other end in the axial direction of the cylindrical portion; and a sealing body for closing the opening of the outer can, wherein the outer can has a bottomed recess between a first location that axially overlaps the radial outer end of the sealing body on one side in the axial direction and a second location in the groove portion that is located furthest axially towards the bottom.

[0007] According to the cylindrical battery described herein, the venting mechanism can be eliminated from the sealing body, and the contents can be ejected from the axial sealing body side when the internal pressure rises.

[0008] This is an axial cross-sectional view of a cylindrical battery according to one embodiment of the present disclosure. This is a perspective view of the electrode body of the cylindrical battery. This is an enlarged cross-sectional view of the area around the grooved portion in Figure 1. This is an enlarged cross-sectional view corresponding to Figure 3 in a modified cylindrical battery.

[0009] Hereinafter, embodiments of the cylindrical battery according to this disclosure will be described in detail with reference to the drawings. The cylindrical battery of this disclosure may be a primary battery or a secondary battery. Furthermore, the cylindrical battery of this disclosure may be a battery using an aqueous electrolyte or a battery using a non-aqueous electrolyte. In the following, a non-aqueous electrolyte cylindrical secondary battery (lithium-ion battery) using a non-aqueous electrolyte will be given as an example of one embodiment of the cylindrical battery 10, but the cylindrical battery of this disclosure is not limited to this.

[0010] It is intended from the outset that new embodiments can be constructed by appropriately combining the characteristic features of the embodiments and modifications described below. In the following embodiments, the same components are denoted by the same reference numerals in the drawings, and redundant explanations are omitted. Multiple drawings include schematic diagrams, and the dimensional ratios such as length, width, and height of each component do not necessarily match between different drawings. In this specification, the side of the cylindrical battery 10 with the sealing body 17 in the axial direction (height direction) is referred to as "upper," and the side of the outer casing 16 with the bottom 68 in the axial direction is referred to as "lower."

[0011] In the following description, "radial direction" refers to the radial direction of the cylindrical battery 10, which coincides with the radial direction of the outer casing 16. Furthermore, among the components described below, those not described in the independent claim representing the highest-level concept are optional components and not essential components. In other words, the numerous components described below include several optional components that are not essential.

[0012] Figure 1 is an axial cross-sectional view of a cylindrical battery 10 according to one embodiment of the present disclosure, and Figure 2 is a perspective view of the electrode body 14 of the cylindrical battery 10. As shown in Figure 1, the cylindrical battery (hereinafter simply referred to as "battery") 10 comprises a wound electrode body 14, a non-aqueous electrolyte (not shown), a bottomed cylindrical metal outer casing 16 that houses the electrode body 14 and the non-aqueous electrolyte, and a sealing body 17 that closes the opening of the outer casing 16 via a gasket 28. The gasket 28 is preferably made of an insulating material with excellent compressibility and resistance, and is made of a resin material or the like. The gasket 28 is preferably made of polyolefin, and more specifically, PP (polypropylene), PPS (polyphenylene sulfide), PFA (perfluoroalkoxyalkane), or PPT (polypropylene terephthalate), etc.

[0013] As shown in Figure 2, the electrode body 14 has a wound structure in which a long positive electrode 11 and a long negative electrode 12 are wound around two long separators 13. The negative electrode 12 is formed to be slightly larger than the positive electrode 11 in order to prevent lithium deposition. That is, the negative electrode 12 is formed to be longer than the positive electrode 11 in both the longitudinal and widthwise (short-side) directions. The two separators 13 are formed to be at least slightly larger than the positive electrode 11 and are arranged, for example, to sandwich the positive electrode 11. The negative electrode 12 may constitute the starting end of the winding of the electrode body 14. However, generally, the separators 13 extend beyond the starting end of the winding of the negative electrode 12, and the starting end of the winding of the separators 13 becomes the starting end of the winding of the electrode body 14.

[0014] Non-aqueous electrolytes are ionic conductive (e.g., lithium ion conductive). Non-aqueous electrolytes may be liquid electrolytes (electrolytes) or solid electrolytes. Liquid electrolytes (electrolytes) contain a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. Examples of non-aqueous solvents include esters, ethers, nitriles, amides, and mixtures of two or more of these. Examples of non-aqueous solvents include ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and mixtures thereof. Non-aqueous solvents may contain halogen-substituted compounds (e.g., fluoroethylene carbonate) in which at least some of the hydrogen atoms in these solvents are replaced with halogen atoms such as fluorine. Examples of electrolyte salts include LiPF4. ６ Lithium salts such as these are used.

[0015] As solid electrolytes, for example, solid or gel-like polymer electrolytes, inorganic solid electrolytes, etc., are used. Polymer electrolytes include, for example, a lithium salt and a matrix polymer, or a non-aqueous solvent, a lithium salt and a matrix polymer. As matrix polymers, for example, polymer materials that absorb non-aqueous solvents and gel are used. As polymer materials, for example, fluororesins, acrylic resins, polyether resins, etc., are used. As inorganic solid electrolytes, for example, materials known for all-solid-state lithium-ion secondary batteries, etc. (for example, oxide-based solid electrolytes, sulfide-based solid electrolytes, halide-based solid electrolytes, etc.) are used.

[0016] The positive electrode 11 comprises a positive electrode current collector and a positive electrode mixture layer formed on both sides of the positive electrode current collector. The positive electrode current collector can be made of a metal foil that is stable within the potential range of the positive electrode 11, such as aluminum or an aluminum alloy, or a film with the metal arranged on its surface. The positive electrode mixture layer contains a positive electrode active material, a conductive agent, and a binder. The positive electrode 11 can be manufactured, for example, by applying a positive electrode mixture slurry containing a positive electrode active material, a conductive agent, and a binder onto the positive electrode current collector, drying the coating, and then compressing it to form the positive electrode mixture layer on both sides of the current collector.

[0017] 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. A preferred example of a lithium-containing metal composite oxide is a composite oxide containing at least one of Ni, Co, Mn, and Al.

[0018] Examples of conductive agents included in the positive electrode mixture layer include carbon black such as acetylene black and Ketjen black, and carbon materials such as graphite. Examples of binders included in the positive electrode mixture layer include fluororesins such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), polyimide resins, acrylic resins, and polyolefin resins. These resins may be used in combination with cellulose derivatives such as carboxymethylcellulose (CMC) or its salts, polyethylene oxide (PEO), etc.

[0019] The negative electrode 12 comprises a negative electrode current collector and a negative electrode mixture layer formed on both sides of the negative electrode current collector. The negative electrode current collector can be made of a metal foil that is stable within the potential range of the negative electrode 12, such as copper or a copper alloy, or a film with the metal arranged on its surface. The negative electrode mixture layer contains a negative electrode active material and a binder. The negative electrode 12 can be manufactured, for example, by applying a negative electrode mixture slurry containing the negative electrode active material and binder onto the negative electrode current collector, drying the coating, and then compressing it to form the negative electrode mixture layer on both sides of the current collector.

[0020] Generally, carbon materials that reversibly intercept and release lithium ions are used as the negative electrode active material. Preferred carbon materials are graphite such as natural graphite such as flake graphite, lump graphite, and clay graphite, and artificial graphite such as lump graphite and graphitized mesophase carbon microbeads. The negative electrode mixture layer may contain silicon (Si) material as the negative electrode active material. In addition, metals that alloy with lithium other than Si, alloys containing such metals, compounds containing such metals, etc., may be used as the negative electrode active material.

[0021] The binder included in the negative electrode mixture layer may be fluororesin, PAN, polyimide resin, acrylic resin, polyolefin resin, etc., as in the case of the positive electrode 11, but preferably styrene-butadiene rubber (SBR) or a modified version thereof is used. In addition to SBR, the negative electrode mixture layer may also contain, for example, CMC or a salt thereof, polyacrylic acid (PAA) or a salt thereof, polyvinyl alcohol, etc.

[0022] A porous sheet having ion permeability and insulating properties is used for the separator 13. Specific examples of porous sheets include microporous thin films, woven fabrics, and nonwoven fabrics. The material of the separator 13 is preferably polyethylene, polyolefin resins such as polypropylene, or 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.

[0023] As shown in Figure 1, a positive electrode lead 20 is joined to the positive electrode 11, and a negative electrode lead 21 is joined to the end of the negative electrode 12 on the winding end side in the longitudinal direction. The battery 10 has an insulating plate 18 above the electrode body 14 and an insulating plate 19 below the electrode body 14. One end of the positive electrode lead 20 is joined to the positive electrode current collector of the positive electrode 11 of the electrode body 14. In this embodiment, the sealing body 17 is composed of only one disc-shaped metal sealing plate. The positive electrode lead 20 extends towards the sealing body 17 side through a through hole in the insulating plate 18, and is then connected to the lower surface 30 of the sealing body 17 by welding or the like, so that the sealing body 17 becomes the positive electrode terminal.

[0024] The negative electrode lead 21 extends from the outside of the insulating plate 19 to the bottom 68 side of the outer casing 16. The negative electrode lead 21 is connected to the inner surface of the bottom 68 of the metal outer casing 16 by welding or the like, so that the outer casing 16 becomes the negative electrode terminal. In the example shown in Figures 1 and 2, the positive electrode lead 20 is electrically connected to an intermediate part of the positive electrode current collector, such as the center in the winding direction, and the negative electrode lead 21 is electrically connected to the end of the negative electrode current collector, on the winding end side in the winding direction. However, the battery may have multiple positive electrode leads, each with one end joined to multiple locations on the positive electrode current collector spaced apart in the longitudinal direction of the positive electrode, and the other end of each positive electrode lead may be joined to a current collector plate included in the sealing body by welding or the like. Alternatively, the upper end of the electrode body may be formed by a strip-shaped positive electrode current collector exposed portion (a portion in which the positive electrode current collector is exposed without a positive electrode mixture layer), and this positive electrode current collector exposed portion may be joined to the current collector plate included in the sealing body by welding or the like.

[0025] The negative electrode lead may be electrically connected to the winding start end in the winding direction of the negative electrode current collector. Alternatively, the electrode body may have two negative electrode leads, with one end of one negative electrode lead electrically connected to the winding start end in the winding direction of the negative electrode current collector and the other end of the negative electrode lead electrically connected to the outer casing. Furthermore, one end of the other negative electrode lead may be electrically connected to the winding end in the winding direction of the negative electrode current collector and the other end of the negative electrode lead electrically connected to the outer casing.

[0026] Alternatively, one end of a negative electrode lead may be electrically connected to the winding start end of the negative electrode current collector in the winding direction, and the other end of the negative electrode lead may be electrically connected to the outer casing. Furthermore, regardless of whether or not there is a negative electrode lead to electrically connect the negative electrode and the outer casing, the negative electrode and the outer casing may be electrically connected by bringing the winding end of the negative electrode current collector in the winding direction into contact with the inner surface of the outer casing. Alternatively, the lower end of the electrode body may be composed of a wound strip-shaped negative electrode current collector exposed portion (a portion in which the negative electrode current collector is exposed without a negative electrode mixture layer), and this negative electrode current collector exposed portion may be joined to the upper surface of the current collector plate by welding or the like, while the lower surface of the current collector plate may be joined to the bottom of the outer casing by welding or the like. In addition, the negative electrode may be electrically connected to the sealing body, and the positive electrode may be electrically connected to the outer casing.

[0027] The peripheral edge 51 of the sealing body 17 is crimped and fixed to the opening of the outer casing 16 via a gasket 28. This seals the internal space of the battery 10. The gasket 28 is sandwiched between the outer casing 16 and the peripheral edge 51, insulating the sealing body 17 from the outer casing 16. The gasket 28 serves as a sealing material to maintain airtightness inside the battery and as an insulating material to insulate the outer casing 16 from the sealing body 17. The outer casing 16 has a cylindrical portion 50 and a bottom portion 68, and the cylindrical portion 50 includes a shoulder portion 38 and a grooved portion 34. The outer casing 16 houses the electrode body 14 and a non-aqueous electrolyte. The grooved portion 34 can be formed, for example, by spinning a part of the side surface of the outer casing 16 radially inward to create an annular recess radially inward. The shoulder portion 38 is formed by crimping and fixing the peripheral portion 51 to the outer can 16, and bending the upper end of the outer can 16 inward toward the peripheral portion 51.

[0028] The sealing body of the cylindrical battery according to this disclosure does not have a vent mechanism that discharges contents (high-temperature gas or molten material) to the outside by rupturing based on an increase in internal pressure due to an internal short circuit or the like. The sealing body may also be composed of multiple members, for example, it may have a structure in which a sealing plate and a current collector plate on which a plurality of positive electrode leads are welded by laser welding or the like, and the lower surface on the outer circumference of the sealing plate and the upper surface on the outer circumference of the current collector plate are joined by laser welding or the like. Alternatively, the sealing body may have a structure in which a sealing plate and a current collector plate on which the exposed portion of the positive electrode current collector constituting the upper end of the electrode body is welded by laser welding or the like, and the sealing plate and the current collector plate are integrated as a single unit.

[0029] Figure 3 is an enlarged cross-sectional view of the area around the grooved portion in Figure 1. As shown in Figure 3, the outer can 16 has a bottomed recess 70 between a first location K1 that axially overlaps the sealing body 17 on one axial side (axially upper side) at the radially outer end of the grooved portion 34 and a second location K2 that is located furthest axially towards the bottom 68. In this embodiment, the recess 70 is a bottomed annular groove that extends substantially circumferentially around the entire circumference and is provided on the outer surface of the outer can 16. It is located axially towards the bottom 68 than a fourth location K4 of the outer can 16 that radially overlaps the third location K3, which is located furthest axially towards the bottom 68 of the sealing body 17, on the radially outer side. More specifically, the recess 70 is located axially towards the sealing body 17 than a fifth location K5, which is located furthest radially inward of the grooved portion 34, and is provided in an annular portion 71 that extends in a direction substantially perpendicular to the axial direction.

[0030] The recess 70 can be created, for example, as follows: First, an annular groove extending substantially in the circumferential direction is provided on the cylindrical outer surface of the bottomed cylindrical outer can by cutting the portion corresponding to the annular part along the entire circumference in the circumferential direction. Then, by performing the spinning process described above and the crimping of the opening of the outer can 16 described above, a battery 10 having the recess 70 can be manufactured.

[0031] In the above configuration, if the battery 10 overheats abnormally due to an internal short circuit or the like, and the internal pressure of the battery 10 rises, the recessed portion of the outer casing 16, which has reduced rigidity due to the formation of the recess 70, ruptures, and the contents (high-temperature gas or molten material) are discharged. The area of ​​the outer casing 16 where the recess 70 is provided constitutes an easily ruptured portion that ruptures as the internal pressure rises. This discharge of contents prevents the battery 10 from rupturing due to an excessive rise in internal pressure, thereby increasing the safety of the battery 10.

[0032] According to the battery 10 of this disclosure, easily breakable portions that rupture as the internal pressure rises are provided on the outer can 16 from a first location K1 on the radial outer end of the sealing body 17 that overlaps axially on one side in the axial direction, to a second location K2 in the grooved portion 34 that is located closest to the bottom 68 in the axial direction. Therefore, a vent mechanism that ruptures as the internal pressure rises can be provided on the axial side of the sealing body 17.

[0033] Furthermore, since the vent mechanism is provided on the outer can 16, the vent mechanism can be eliminated from the sealing body 17. Therefore, the structure of the sealing body 17 can be simplified, for example, to a simple disc shape as in this embodiment, and the sealing body 17 can be manufactured easily and with high precision. In this embodiment, when the sealing body 17 is a simple disc shape, it is easy to position the upper surface of the shoulder portion 38 substantially parallel to a direction substantially perpendicular to the axial direction. Therefore, when the upper surface of the shoulder portion is used as an external terminal, it is easy to weld the conductive member to the upper surface of the shoulder portion 38 by laser welding or the like.

[0034] It is preferable that the recess 70 extends substantially in the circumferential direction over the entire circumference and is a bottomed annular groove provided in the outer can 16, so that it can be smoothly and reliably ruptured at a predetermined location when the internal pressure rises. Furthermore, it is preferable that the recess 70 is provided on the outer surface of the outer can 16, so that electrolyte does not accumulate in the recess 70 and cause rust or the like.

[0035] Since the sealing body 17 does not hinder the smooth rupture of the recess 70 when the internal pressure rises, it is preferable that the recess 70 be located below the sealing body 17. More precisely, since the sealing body 17 does not hinder the smooth rupture of the recess 70 when the internal pressure rises, it is preferable that the recess 70 be located axially towards the bottom 68 (axially downward) of the fourth location K4 of the outer can 16, which radially overlaps the third location K3, which is located on the axial bottom 68 side of the sealing body 17, on the radially outward side.

[0036] It is preferable that the recess 70 be provided in the grooved portion 34, as this makes it easier to achieve a beautiful appearance even when the recess 70 is provided on the outer surface. Furthermore, it is preferable that the recess 70 be provided in the annular portion 71 which extends in a direction substantially perpendicular to the axial direction, and is located axially towards the sealing body 17 (upper axial direction) than the fifth location K5, which is located furthest radially inward in the grooved portion 34.

[0037] It is preferable to construct the sealing body 17 from a single metal sealing plate, as this makes the fabrication of the sealing body 17 significantly easier. Furthermore, it is preferable that the minimum thickness of the sealing plate be 0.2 mm or less, as this makes it easier to fabricate the sealing plate. Additionally, it is preferable that the maximum thickness of the sealing plate be 2.0 mm or less, as this makes it easier to fabricate a compact battery 10 and to enlarge the electrode body 14, thereby increasing the capacity.

[0038] Since the recessed portion (easily breakable portion) in the outer casing 16 can be smoothly broken when the internal pressure of the battery 10 rises, it is preferable that the ratio of the depth of the recess 70 to the sum of the depth of the recess 70 and the minimum thickness of the recessed portion of the outer casing 16 is 0.3 or more. Furthermore, since the rigidity of the outer casing 16 can be made good when the battery 10 is not overheating, it is preferable that the ratio of the depth of the recess 70 to the sum of the depth of the recess 70 and the minimum thickness of the recessed portion of the outer casing 16 is 0.6 or less.

[0039] This disclosure is not limited to the embodiments and their modifications described above, and various improvements and modifications are possible within the scope of the claims of this application and their equivalents. For example, the case described is when the recess 70 is a bottomed annular groove that extends substantially circumferentially over the entire circumference and is provided on the outer surface of the outer can 16. However, the outer can may have a plurality of non-annular recesses provided at substantially the same positions in the axial direction, and the plurality of non-annular recesses may be spaced apart in the circumferential direction, preferably at substantially equal intervals in the circumferential direction. Alternatively, the outer can may have only one non-annular recess. Furthermore, although the case described is when the recess 70 is provided on the outer surface of the outer can, the recess may be provided on the inner surface of the outer can.

[0040] The case in which the recess 70 is provided in the annular portion 71 above the grooved portion 34 has been described. However, in the cylindrical battery of this disclosure, it is sufficient to provide a bottomed recess between the outer can, from a first location that axially overlaps on one axial side of the radial outer end of the sealing body to a second location that is located on the bottom side in the axial direction in the grooved portion. For example, as shown in Figure 4, the recess 170 may be provided on the cylindrical outer surface 180 located between the shoulder portion 138 and the grooved portion 134 of the outer can 116. In this case, it is preferable that the recess 170 is an annular groove that extends substantially in the circumferential direction over the entire circumference. A curved portion exists at the uppermost corner of the outer can (the radially outer corner of the shoulder). If the position where the curved portion ends when moving downward is called the R-stop position (bend stop position), it is preferable that the recess is located below the R-stop position (closer to the electrode body than the R-stop position).

[0041] Furthermore, the cylindrical battery of this disclosure may have the following configurations: Configuration 1: A cylindrical battery comprising an electrode body in which a positive electrode and a negative electrode are wound with a separator between them, a cylindrical portion including a shoulder portion extending radially inward at one end in the axial direction and a groove portion recessed radially inward along the entire circumference in the circumferential direction, and a bottom portion that closes the opening on the other side in the axial direction of the cylindrical portion, and a sealing body for closing the opening of the outer casing, wherein the outer casing has a bottomed recess between a first location that axially overlaps the radial outer end of the sealing body on one side in the axial direction and a second location in the groove portion that is located furthest axially towards the bottom. Configuration 2: The cylindrical battery according to Configuration 1, wherein the bottomed recess is provided axially towards the bottom than a fourth location in the outer casing that radially overlaps the third location in the sealing body that is located furthest axially towards the bottom. Configuration 3: The cylindrical battery according to Configuration 1 or 2, wherein the sealing body is composed of a single metal sealing plate, and the minimum axial thickness of the sealing body is 0.2 mm or more. Configuration 4: The cylindrical battery according to any one of Configurations 1 to 3, wherein the recess is a bottomed annular groove that extends substantially circumferentially around the entire circumference and is provided on the outer surface of the outer casing. Configuration 5: The cylindrical battery according to any one of Configurations 1 to 4, wherein the recess is located axially closer to the sealing body than the fifth location, which is the radially innermost location in the groove, and is provided in an annular portion that extends in a direction substantially perpendicular to the axial direction.

[0042] 10 Battery, 11 Positive electrode, 12 Negative electrode, 13 Separator, 14 Electrode body, 16, 116 Outer can, 17 Sealing body, 18, 19 Insulating plate, 20 Positive electrode lead, 21 Negative electrode lead, 28 Gasket, 30 Bottom surface of sealing body, 34, 134 Grooved portion, 38, 138 Shoulder portion, 50 Cylindrical portion, 51 Peripheral portion, 68 Bottom portion, 70, 170 Bottomed recess, 71 Annular portion, 180 Cylindrical outer surface, K1 First location, K2 Second location, K3 Third location, K4 Fourth location, K5 Fifth location.

Claims

1. A cylindrical battery comprising: an electrode body in which a positive electrode and a negative electrode are wound with a separator between them; a cylindrical outer can containing the electrode body, having a shoulder portion extending radially inward at one end in the axial direction and a groove portion recessed radially inward along the entire circumference in the circumferential direction, and a bottom portion that closes the opening on the other end in the axial direction of the cylindrical portion; and a sealing body for closing the opening of the outer can, wherein the outer can has a bottomed recess between a first location that axially overlaps the radial outer end of the sealing body on one side in the axial direction and a second location in the groove portion that is located furthest axially towards the bottom.

2. The cylindrical battery according to claim 1, wherein the bottomed recess is provided on the third location in the sealing body that is located on the bottom side in the axial direction, and is located radially outward from the fourth location of the outer casing that radially overlaps it.

3. The cylindrical battery according to claim 1 or 2, wherein the sealing body is composed of a single metal sealing plate, and the minimum axial thickness of the sealing body is 0.2 mm or more.

4. The cylindrical battery according to claim 1 or 2, wherein the recess is a bottomed annular groove that extends substantially in the circumferential direction over the entire circumference and is provided on the outer surface of the outer casing.

5. The cylindrical battery according to claim 1 or 2, wherein the recess is located on the axial side of the sealing body, closer to the fifth location which is the radially innermost of the grooved portion, and is provided in an annular portion that extends in a direction substantially perpendicular to the axial direction.

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