Cylindrical battery

Abstract

This cylindrical battery is characterized by comprising: a wound electrode body (14); a cylindrical outer can (16) that accommodates the electrode body (14); a sealing body (17) that closes an opening of the outer can (16); and an insulating member (30) that is disposed on the outer side in the axial direction of the electrode body (14), the insulating member (30) having at least one or more protrusions (32).

Description

Cylindrical battery

[0001] The present disclosure relates to cylindrical batteries.

[0002] A cylindrical battery generally includes 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 body that closes the opening of the outer can (see, for example, Patent Document 1). The outer can of a cylindrical battery has an annular groove formed on its outer circumferential surface, and a grooved portion that protrudes radially inward on a portion of its inner circumferential surface. The grooved portion supports the sealing body and presses against the outer circumferential portion of the electrode assembly to prevent the electrode assembly from moving.

[0003] Japanese Patent Application Laid-Open No. 2004-111105

[0004] As described above, the grooves in the outer can contribute to preventing the movement of the electrode assembly, but it is expected that the grooves alone will not be enough to prevent the electrode assembly from moving if the battery is subjected to large vibrations, shocks, etc. In particular, as the diameter of a cylindrical battery increases, the electrode assembly becomes more likely to move, which can cause a shift in the relative positions of the positive electrode, negative electrode, and separator that make up the electrode assembly (so-called winding misalignment).

[0005] A cylindrical battery according to one aspect of the present disclosure comprises a wound electrode body, a cylindrical outer can that houses the electrode body, a sealing body that closes the opening of the outer can, and an insulating member that is arranged axially outside the electrode body, and the insulating member has at least one or more protrusions.

[0006] According to a cylindrical battery according to one aspect of the present disclosure, movement of the electrode assembly within the outer can can be suppressed. The configuration of a cylindrical battery according to the present disclosure is suitable for, for example, a large cylindrical battery with a large diameter.

[0007] FIG. 1 is an axial cross-sectional view of a cylindrical battery of a first embodiment; FIG. 2 is a plan view of an insulating member constituting the cylindrical battery of the first embodiment, as seen from above; FIG. 3 is a plan view of an insulating member constituting the cylindrical battery of the first embodiment, as seen from above; FIG. 4 is an axial cross-sectional view of a cylindrical battery of a second embodiment; FIG. 5 is a plan view of an insulating member constituting the cylindrical battery of the second embodiment, as seen from below; FIG. 6 is an axial cross-sectional view of a cylindrical battery of a third embodiment; FIG. 7 is a perspective view of the upper part of a cylindrical battery of a third embodiment, showing a state before the sealing body is crimped and fixed; FIG. 8 is a perspective view of an insulating member constituting the cylindrical battery of the third embodiment, showing a state before the sealing body is crimped and fixed; FIG. 9 is a radial cross-sectional view of an insulating member constituting the cylindrical battery of the third embodiment, showing an enlarged view of the vicinity of a connecting portion; FIG. 10 is a radial cross-sectional view of an insulating member constituting the cylindrical battery of the third embodiment, showing an enlarged view of the vicinity of a connecting portion; FIG. 11 is an axial cross-sectional view of a cylindrical battery of a fourth embodiment; FIG. 12 is a plan view of an insulating member constituting the cylindrical battery of the fourth embodiment, as seen from below.

[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 formed by selectively combining the components of the multiple embodiments and variations described below are included within the scope of the present disclosure.

[0009] [First Embodiment] Fig. 1 is an axial cross-sectional view of a cylindrical battery 10 according to a first 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 has 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 ease 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 constituting the electrode assembly 14 are all strip-shaped, long 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 deposition. 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. Two positive electrode leads 20 connected to the positive electrode 11 by welding or the like and one negative electrode lead 21 connected to the negative electrode 12 by welding or the like are connected to the electrode assembly 14. The number of positive electrode leads 20 and negative electrode leads 21 is not limited thereto.

[0011] 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 a foil of a metal that is 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 the 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.

[0012] 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, a copper alloy, stainless steel, nickel, or a nickel alloy, or a film having 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 to which the negative electrode lead 21 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.

[0013] 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.

[0014] 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.

[0015] 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

[0016] 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.

[0017] As will be described in more detail below, an insulating member 30 having a circular shape on its upper surface is disposed between the electrode body 14 and the sealing body 17. The insulating member 30 not only prevents contact between the electrode body 14 and the grooved portion 22 formed in the outer can 16, but also functions to prevent movement of the electrode body 14 within the outer can 16 by pressing down on the electrode body 14 from above.

[0018] Positive electrode lead 20 passes through a through hole 30A provided in the radial center of insulating member 30 and extends toward sealing body 17. Positive electrode lead 20 is bent so as to fit along the upper surface of upper terminal plate 23 that constitutes sealing body 17, and is joined to the upper surface of upper terminal plate 23 by welding or the like. In this way, sealing body 17 serves as a positive electrode terminal.

[0019] A lower insulating plate 18 is disposed below the electrode body 14. A negative electrode lead 21 passes outside the lower insulating plate 18 and extends to the bottom side of the outer can 16. The negative electrode lead 21 is joined to the inner surface of the bottom of the outer can 16 by welding or the like. This makes the outer can 16 a negative electrode terminal. The outer can 16 and the sealing body 17 are connected to an external circuit, for example, other batteries that constitute the battery module, a charger, or the like.

[0020] The outer can 16 is a cylindrical metal container with a bottom and an opening on one axial side, and the opening of the outer can 16 is closed by a sealing body 17. A gasket 25 is provided between the outer can 16 and the sealing body 17 to ensure that the inside of the battery is airtight.

[0021] The exterior can 16 has a grooved portion 22 formed in a side surface that protrudes inward and supports the sealing body 17. The grooved portion 22 is preferably formed in an annular shape along the circumferential direction of the exterior can 16, and supports the sealing body 17 on its upper surface. The grooved portion 22 also functions to suppress movement of the electrode body 14 by pressing down on the outer periphery of the electrode body 14.

[0022] The sealing body 17 has a function of sealing the opening of the outer can 16. In this embodiment, the sealing body 17 is composed of an upper terminal plate 23 to which the positive electrode lead 20 is joined, and a sealing plate 24 that covers the upper terminal plate 23. The sealing body 17 is fixed to the opening of the outer can 16 by crimping via a gasket 25. Note that the configuration of the sealing body 17 is not limited to this, as long as it is capable of sealing the opening of the outer can 16.

[0023] The upper terminal plate 23 is an annular metal plate-like member having a through-hole in the center. The upper terminal plate 23 has a recessed portion on the lower side, to which the positive electrode lead 20 is joined. The outer periphery of the upper terminal plate 23 abuts against the outer periphery of the sealing plate 24. In addition, the outer periphery of the upper terminal plate 23 is preferably joined to the sealing plate 24 by laser welding or the like.

[0024] The sealing plate 24 is a metal plate-like member that does not have any through holes. A convex portion that protrudes toward the outside of the battery is provided in the center of the sealing plate 24. The convex portion has, for example, a substantially circular shape when viewed from above.

[0025] Next, the insulating member 30 will be described in detail with further reference to Fig. 2. Fig. 2 is a plan view of the insulating member 30 as viewed from above. Note that in Fig. 2, the region where the protrusions 32, which will be described later, are provided is shown hatched.

[0026] 1 and 2 , the insulating member 30 is a circular member having a base 31 that abuts against the upper surface of the electrode body 14 and a protrusion 32 that protrudes from the base 31 toward the sealing body 17 (upward). As described above, the insulating member 30 prevents an internal short circuit from occurring due to contact between the electrode body 14 and the grooved portion 22. The thickness of the insulating member 30 is, for example, 0.3 mm or more and 10.0 mm or less, and may be 0.5 mm or more and 5.0 mm or less. In this embodiment, the base 31 and the protrusion 32 each have approximately the same thickness.

[0027] The insulating member 30 has a protrusion 32, which can prevent the electrode body 14 from moving even when the battery is subjected to large vibrations, shocks, etc., or when the diameter of the cylindrical battery 10 is large. Specifically, when the electrode body 14 moves upward and the insulating member 30 is pushed upward, the protrusion 32 comes into contact with the sealing body 17, thereby restricting the upward movement of the electrode body 14.

[0028] The height of the protrusion 32 is preferably 50% or more, and more preferably 90% or more, of the distance from the upper end of the electrode body 14 to the lower end of the sealing body 17 (upper terminal plate 23). By making the height of the protrusion 32 50% or more of the distance from the upper end of the electrode body 14 to the lower end of the sealing body 17, movement of the electrode body 14 can be further suppressed. The height of the protrusion 32 is, for example, 0.5 mm or more and 10.0 mm or less, or may be 1.0 mm or more and 5.0 mm or less. The height of the protrusion 32 refers to the length along the axial direction (vertical direction) from the lower surface of the insulating member 30 (base 31) to the apex (upper end) of the protrusion 32. In this embodiment, the protrusion 32 does not abut the lower surface of the upper terminal plate 23, but the protrusion 32 may abut the lower surface of the upper terminal plate 23.

[0029] As shown in FIG. 2 , the insulating member 30 has a plurality of protrusions 32 arranged radially. Specifically, the plurality of protrusions 32 extend radially outward from the center of the insulating member 30 and are arranged at approximately equal angular intervals in the circumferential direction. By arranging the protrusions 32 radially, when the electrode body 14 moves upward and hits the insulating member 30, the load applied to the electrode body 14 from the insulating member 30 can be alleviated. This makes it possible to suppress damage to the electrode body 14. Furthermore, by arranging the protrusions 32 radially, it is possible to suppress the electrode body 14 from shifting in the circumferential direction. This makes it possible to suppress the occurrence of shear in the winding of the electrode body 14.

[0030] When viewed from above, the ratio of the area of ​​the region where the protrusions 32 are provided to the total area of ​​the insulating member 30 is, for example, 10% or more and 80% or less, and may be 20% or more and 70% or less. Increasing the ratio of the area of ​​the region where the protrusions 32 are provided to the total area of ​​the insulating member 30 makes it easier to suppress movement of the electrode body 14. On the other hand, decreasing the ratio of the area of ​​the region where the protrusions 32 are provided to the total area of ​​the insulating member 30 makes it easier to reduce the load applied from the insulating member 30 to the electrode body 14, and makes it easier to suppress damage to the electrode body 14.

[0031] One through-hole 30A is provided in the center of the insulating member 30. In this embodiment, the positive electrode lead 20 extending from the positive electrode 11 passes through the through-hole 30A. Furthermore, by providing the through-hole 30A in the insulating member 30, when gas is generated inside the battery due to abnormal heat generation or the like in the battery, the gas can be exhausted through the through-hole 30A. Furthermore, by providing the through-hole 30A in the insulating member 30, it is possible to improve the injection efficiency when injecting an electrolyte into the exterior can 16 during the battery manufacturing process.

[0032] The material of the insulating member 30 is not particularly limited, but examples of materials that can be used include polypropylene (PP), polyphenylene sulfide (PPS), polyethylene (PE), polybutylene terephthalate (PBT), perfluoroalkoxyalkane (PFA), polytetrafluoroethylene (PTFE), polyamide (PA), etc. The insulating member 30 can be produced by, for example, injection molding.

[0033] In the above embodiment, the insulating member 30 has a substantially uniform thickness throughout the entire area, including the area where the protrusions 32 are provided. However, this is not limiting. For example, the insulating member 30 may be formed so that the area where the protrusions 32 are provided is thicker. In this case, the lower surface of the insulating member 30 may be formed on the same plane throughout the entire area.

[0034] In the above embodiment, the protrusions 32 are arranged radially, but the shape and arrangement of the protrusions 32 are not limited to this. For example, as shown in Fig. 3, the protrusions 32 may have a circular ring shape or an arc shape extending in the circumferential direction. In Fig. 3, the area where the protrusions 32 are provided is illustrated by hatching, as in Fig. 2.

[0035] In the above embodiment, one through-hole 30A is provided in the central portion of the insulating member 30, but this is not limiting. For example, the through-hole 30A may be provided in the outer periphery of the insulating member 30 instead of or in addition to the central portion of the insulating member 30.

[0036] Furthermore, the insulating member 30 may be provided with a plurality of through holes 30A. When the insulating member 30 is provided with a plurality of through holes 30A, for example, some of the through holes 30A may not be passed through by the positive electrode lead 20. By providing a plurality of through holes 30A, it is possible to improve the ability to exhaust gas when gas is generated inside the battery due to abnormal heat generation or the like in the battery. Furthermore, by providing a plurality of through holes 30A, it is possible to further improve the ability to inject electrolyte into the exterior can 16 during the battery manufacturing process.

[0037] Second Embodiment Next, the configuration of a cylindrical battery 10X according to a second embodiment will be described with reference to Figures 4 and 5. Figure 4 is an axial cross-sectional view of the cylindrical battery 10X, and Figure 5 is a plan view of the insulating member 30 as viewed from below. In Figure 5, the area where the protrusions 32 are provided is shown hatched. Below, the same reference numerals are used for components common to the first embodiment, and redundant explanations are omitted. Differences from the first embodiment will be mainly described.

[0038] 4, the cylindrical battery 10X of the second embodiment is the same as the cylindrical battery 10 of the first embodiment in that it 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. However, the cylindrical battery 10X of the second embodiment differs from the first embodiment in that it does not include a gasket 25 (see FIG. 1), and instead an insulating member 30 functions as the gasket 25.

[0039] 4 and 5 , the insulating member 30 has an outer circumferential portion 33 that axially sandwiches the outer periphery of the sealing body 17, an inner circumferential portion 34 that faces the top surface of the electrode body 14, and a connecting portion 35 that connects the outer circumferential portion 33 and the inner circumferential portion 34. The sealing body 17 is fixed to the opening of the outer can 16 by crimping via the outer circumferential portion 33. In other words, the outer circumferential portion 33 functions as the gasket 25 in the cylindrical battery 10 of the first embodiment. By having the insulating member 30 function as the gasket 25, the number of parts that make up the cylindrical battery 10X can be reduced.

[0040] The outer peripheral portion 33 is disposed between the sealing body 17 and the outer can 16, and is formed in a ring shape along the circumferential direction of the outer can 16. The size, shape, etc. of the outer peripheral portion 33 are not particularly limited as long as they can ensure airtightness inside the battery when the sealing body 17 is crimped and fixed to the opening of the outer can 16 via the outer peripheral portion 33. Furthermore, by fixing the outer peripheral portion 33 to the opening of the outer can 16, the insulating member 30 is prevented from shifting inside the outer can 16. As a result, damage to the positive electrode lead 20 due to contact of the insulating member 30 with the positive electrode lead 20 can be prevented.

[0041] The inner circumferential portion 34 is disposed closer to the electrode body 14 than the outer circumferential portion 33 and faces the upper surface of the electrode body 14. The inner circumferential portion 34 is provided with a protrusion 32 that protrudes toward the electrode body 14 (downward). By providing the protrusion 32 on the inner circumferential portion 34, movement of the electrode body 14 can be suppressed even when the battery is subjected to large vibrations, impacts, etc., or when the diameter of the cylindrical battery is large. Specifically, when the electrode body 14 moves upward, the electrode body 14 hits the protrusion 32, thereby restricting the upward movement of the electrode body 14. Furthermore, a through-hole 30A through which the positive electrode lead 20 passes is provided in the center of the inner circumferential portion 34.

[0042] The height of the protrusions 32 is preferably 50% or more, and more preferably 70% or more, of the distance from the upper end of the electrode body 14 to the lower end of the sealing body 17 (upper terminal plate 23). By making the height of the protrusions 32 50% or more of the distance from the upper end of the electrode body 14 to the lower end of the sealing body 17, movement of the electrode body 14 can be further suppressed. Note that the height of the protrusions 32 refers to the length along the axial direction (up-down direction) from the upper surface of the inner circumferential portion 34 to the apex (lower end) of the protrusions 32. In this embodiment, the protrusions 32 do not abut the upper surface of the electrode body 14, but the protrusions 32 may abut the upper surface of the electrode body 14.

[0043] 5, the protrusions 32 are arranged radially, as in the first embodiment. Specifically, the protrusions 32 extend radially outward from the center of the insulating member 30 and are arranged at approximately equal angular intervals in the circumferential direction. Note that the protrusions 32 may have a ring shape or an arc shape extending in the circumferential direction.

[0044] The connecting portion 35 is a portion that connects the outer peripheral portion 33 and the inner peripheral portion 34. The connecting portion 35 has a shape that gradually inclines toward the electrode body 14 as it approaches the center in the radial direction. Note that the connecting portion 35 may extend along the axial direction, as shown in a third embodiment described later. The connecting portion 35 is provided, for example, around the entire circumference of the inner peripheral portion 34.

[0045] The thickness of the connecting portion 35 is not particularly limited, and may be, for example, greater than the thickness of the inner circumferential portion 34. The thickness of the connecting portion 35 may also vary in the radial direction. For example, the thickness of the connecting portion 35 may become thinner as it approaches the center in the radial direction.

[0046] [Third Embodiment] Next, the configuration of a cylindrical battery 10Y according to a third embodiment will be described with reference to Figures 6 to 10. Figure 6 is an axial cross-sectional view of the cylindrical battery 10Y, Figure 7 is a perspective view of the upper part of the cylindrical battery 10Y, showing the state before the sealing body 17 is crimped and fixed, and Figure 8 is a perspective view of the insulating member 30, showing the state before the sealing body 17 is crimped and fixed. Below, the same reference numerals will be used for components common to the second embodiment, and redundant explanations will be omitted. Differences from the second embodiment will be mainly described.

[0047] 6 and 7 , the cylindrical battery 10Y of the third embodiment is similar to the cylindrical battery 10X of the second embodiment in that it 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, but does not include a gasket 25 (see FIG. 1 ). On the other hand, the cylindrical battery 10Y of the third embodiment differs from the second embodiment in that it includes six positive electrode leads 20 and includes current collecting members 50, to which the positive electrode leads 20 are connected, between the sealing member 17 and the insulating member 30.

[0048] In this embodiment, six positive electrode leads 20 are arranged in pairs, overlapping each other. Each positive electrode lead 20 is bent radially inward at the top of the electrode body 14 and joined to the upper surface of the current collecting member 50 by welding or the like. The number and arrangement of the positive electrode leads 20 are not limited to this. Alternatively, the positive electrode leads 20 may be joined to the lower surface of the current collecting member 50 by welding or the like.

[0049] The current collecting member 50 is disposed between the sealing body 17 and the insulating member 30, and electrically connects the positive electrode lead 20 and the sealing body 17. The current collecting member 50 has a shape wider than the positive electrode lead 20 and a size such that it does not come into contact with the grooved portion 22 of the outer casing can 16. The current collecting member 50 is made of, for example, a metal containing aluminum as a main component.

[0050] Current collecting member 50 has a folded shape when sealing body 17 is crimped and fixed thereto. Specifically, current collecting member 50 has a first region 51 that is joined to sealing plate 24 that constitutes sealing body 17, and a second region 52 that is disposed opposite first region 51 when sealing body 17 is crimped and fixed thereto.

[0051] A weld (not shown) for joining the current collecting member 50 to the sealing plate 24 is formed in the first region 51, and a weld (not shown) for joining the positive electrode lead 20 to the current collecting member 50 is formed in the second region 52. A through hole 50A is also formed in the second region 52. The through hole 50A is formed, for example, in a position overlapping with the winding axis of the electrode body 14. The through hole 50A functions as an exhaust port for gas generated inside the battery when the battery abnormally heats up, for example.

[0052] 6 to 8 , the insulating member 30 has an outer circumferential portion 33 that sandwiches the outer periphery of the sealing body 17 from both axial sides, an inner circumferential portion 34 that faces the top surface of the electrode body 14, and multiple connecting portions 35 that radially connect the outer circumferential portion 33 and the inner circumferential portion 34. The sealing body 17 is fixed to the opening of the outer can 16 by crimping via the outer circumferential portion 33. In other words, the outer circumferential portion 33 functions as the gasket 25 (see FIG. 1) in the cylindrical battery 10 of the first embodiment.

[0053] The inner circumferential portion 34 is provided with a first through hole 36 provided at a position facing the through hole 50A of the current collecting member 50, a second through hole 37 provided at a position facing the fixing portion 40 described below, and three third through holes 38 through which the positive electrode lead 20 passes. In other words, the positive electrode lead 20 does not pass through the first through hole 36 or the second through hole 37. By providing the first through hole 36 and the second through hole 37, it is possible to improve the ability to exhaust gas when gas is generated inside the battery due to abnormal heat generation or the like. The shapes and arrangements of the first through hole 36, the second through hole 37, and the third through hole 38 can be appropriately set depending on the battery size, the shape and number of the positive electrode lead 20, etc.

[0054] As shown in FIG. 8 , four protrusions 32 are provided on the inner circumferential portion 34. In this embodiment, the protrusions 32 have a generally circular shape when viewed from above. The four protrusions 32 are arranged at approximately 90° intervals in the circumferential direction. By providing the protrusions 32 on the inner circumferential portion 34, movement of the electrode body 14 can be suppressed, as described above. The number of protrusions 32 is not limited to this and may be, for example, five or more. The protrusions 32 may also be arranged radially, as in the first embodiment. In this embodiment, the protrusions 32 do not abut against the lower surface of the sealing plate 24, but may abut against the lower surface of the sealing plate 24.

[0055] The inner circumferential portion 34 is provided with a fixing portion 40 for fixing the insulating member 30 and the current collecting member 50. The fixing portion 40 has, for example, a bent shape, and the lower surface of the fixing portion 40 abuts against the upper surface of the second region 52 of the current collecting member 50. As a result, the current collecting member 50 is sandwiched between the inner circumferential portion 34 and the fixing portion 40 and fixed to the insulating member 30. Note that the configuration of the fixing portion 40 is not limited thereto as long as it is possible to fix the insulating member 30 and the current collecting member 50. For example, the fixing portion 40 may have a concave shape that sandwiches the current collecting member 50.

[0056] The connecting portions 35 are portions that connect the outer circumferential portion 33 and the inner circumferential portion 34, and extend along the axial direction. The connecting portions 35 are arranged at predetermined intervals in the circumferential direction. As a result, fourth through holes 39 are formed between adjacent connecting portions 35 in the circumferential direction. By providing the fourth through holes 39, the electrolyte passes through the fourth through holes 39 when it is injected into the exterior can 16 during the battery manufacturing process. This improves the injection of the electrolyte.

[0057] Furthermore, by providing the fourth through hole 39, when the electrode body 14 moves upward and hits the insulating member 30, the connecting portion 35 bends appropriately. This makes it possible to alleviate the load applied to the electrode body 14 from the insulating member 30. As a result, damage to the electrode body 14 due to the load from the insulating member 30 can be suppressed. In other words, by changing the shape, size, etc. of the fourth through hole 39, it is possible to adjust the load applied to the electrode body 14 from the insulating member 30. For example, by enlarging the fourth through hole 39, that is, by making the connecting portion 35 smaller, it is possible to reduce the load applied to the electrode body 14 from the insulating member 30.

[0058] In the circumferential direction, the length of the region where the fourth through holes 39 are formed with respect to the entire circumferential length of the insulating member 30 is, for example, 40% to 90% or less, or may be 50% to 80% or less. In other words, the length of the region where the connecting portions 35 are formed with respect to the entire circumferential length of the insulating member 30 is, for example, 10% to 60% or less, or may be 20% to 50% or less. By setting the length of the region where the fourth through holes 39 with respect to the entire circumferential length of the insulating member 30 to be 40% to 90% or less, it becomes easy to limit the upward movement of the electrode body 14 while mitigating the load applied from the insulating member 30 to the electrode body 14.

[0059] FIG. 9 is a radial cross-sectional view of the insulating member 30 near the connecting portion 35. As shown in FIG. 9 , the insulating member 30 has a first groove 41 and a second groove 42 extending along the circumferential direction. Specifically, the first groove 41 is provided on the lower surface of the radially inner end of the outer circumferential portion 33, and the second groove 42 is provided on the upper surface of the radially outer end of the inner circumferential portion 34. The first groove 41 and the second groove 42 are preferably provided around the entire circumference of the insulating member 30. By providing the first groove 41 and the second groove 42 in the insulating member 30, when the electrode body 14 moves upward, the insulating member 30 bends from the first groove 41 and the second groove 42 as starting points, thereby reducing the load applied from the insulating member 30 to the electrode body 14.

[0060] The size, shape, etc. of the first groove portion 41 and the second groove portion 42 can be set appropriately depending on the battery size, etc. The depth of the first groove portion 41 is, for example, 20% to 80% of the thickness of the outer circumferential portion 33. Similarly, the depth of the second groove portion 42 is, for example, 20% to 80% of the thickness of the inner circumferential portion 34. In this embodiment, the first groove portion 41 has an inclined region in which the groove width increases linearly downward. Furthermore, the second groove portion 42 has an inclined region in which the groove width increases linearly upward.

[0061] The bottoms of the first groove 41 and the second groove 42 have a generally semicircular cross-sectional shape. The bottoms of the first groove 41 and the second groove 42 may have, for example, a V-shape in cross-sectional shape. Furthermore, only one of the first groove 41 and the second groove 42 may be provided in the insulating member 30.

[0062] FIG. 10 is a diagram illustrating a modified shape of the insulating member 30 near the connecting portion 35, and corresponds to FIG. 9 . As shown in FIG. 10 , the insulating member 30 may be provided with a third groove 43 in addition to the first groove 41 and the second groove 42. The third groove 43 is provided on the upper surface of the outer circumferential portion 33 and is positioned radially outward of the first groove 41. By providing the third groove 43 in addition to the first groove 41 and the second groove 42 in the insulating member 30, the load applied from the insulating member 30 to the electrode body 14 when the electrode body 14 moves upward can be further alleviated. In the example shown in FIG. 10 , the third groove 43 has a generally semicircular cross-sectional shape. Note that the third groove 43 may have an inclined region in which the groove width increases linearly upward, similar to the first groove 41 and the second groove 42.

[0063] [Fourth Embodiment] Next, the configuration of a cylindrical battery 10Z according to a fourth embodiment will be described with reference to Figures 11 and 12. Figure 11 is an axial cross-sectional view of the cylindrical battery 10Z, and Figure 12 is a plan view of the insulating member 30 viewed from below. In Figure 12, the area where the protrusions 32 are provided is shown hatched. Below, the same reference numerals are used for components common to the first embodiment, and redundant explanations are omitted. Differences from the first embodiment will be mainly described.

[0064] 11 , a cylindrical battery 10Z of the fourth embodiment includes a wound electrode assembly 14, an electrolyte, and an outer can 16 that houses the electrode assembly 14 and the electrolyte. The outer can 16 is a cylindrical metal container with openings at both axial ends. The opening on the top side of the outer can 16 is closed by a rivet 26 serving as a sealing body 17, and the opening on the bottom side of the outer can 16 is closed by a lower sealing plate 27.

[0065] 11 and 12 , an insulating member 30 is provided on top of the electrode body 14. The insulating member 30 has a through hole 30A in the center. The portion near the through hole 30A is folded back radially outward and is interposed between the outer can 16 and the rivet 26. This allows the gap between the opening of the outer can 16 and the rivet 26 to be sealed.

[0066] The insulating member 30 is provided with a protrusion 32 that protrudes toward (the lower side of) the electrode body 14. By providing the protrusion 32, as described above, movement of the electrode body 14 can be suppressed even when the battery is subjected to large vibrations, impacts, etc., or when the diameter of the cylindrical battery is large.

[0067] 12 , in this embodiment, the protrusions 32 are arranged radially, similar to the second embodiment. Specifically, the multiple protrusions 32 extend radially outward from the center of the insulating member 30 and are arranged at approximately equal angular intervals in the circumferential direction. Note that the protrusions 32 may have a ring shape or an arc shape extending in the circumferential direction.

[0068] The rivet 26 is a metal member, and is fixed to the opening on the top surface side of the outer casing can 16 via an insulating member 30. The positive electrode lead 20 is joined to the rivet 26. As a result, the rivet 26 serves as a positive electrode terminal.

[0069] A lower terminal plate 28 electrically connected to the negative electrode 12 is provided at the bottom of the electrode body 14. The method of connecting the negative electrode 12 and the lower terminal plate 28 is not particularly limited, and for example, a negative electrode core exposed portion 12A that exposes the negative electrode core that constitutes the negative electrode 12 may be provided, and the negative electrode core exposed portion 12A may be joined to the lower terminal plate 28. Alternatively, a negative electrode lead extending from the negative electrode 12 may be joined to the lower terminal plate 28.

[0070] A grooved portion 22, in which part of the side surface protrudes inward, is formed on the bottom side of the outer can 16. A lower sealing plate 27 is crimped and fixed to the bottom of the outer can 16 below the grooved portion 22 via a gasket 29. The method for fixing the lower sealing plate 27 is not limited to this, and for example, the lower sealing plate 27 may be fixed to the bottom of the outer can 16 by welding the outer edge of the lower sealing plate 27 to the bottom of the outer can 16.

[0071] Lower sealing plate 27 is electrically connected to lower terminal plate 28. As a result, lower sealing plate 27 serves as a negative electrode terminal. The method of connecting lower sealing plate 27 and lower terminal plate 28 is not particularly limited, and for example, a lead extending from lower terminal plate 28 may be joined to lower terminal plate 28. Lower sealing plate 27 and lower terminal plate 28 may also be electrically connected via outer can 16.

[0072] The present disclosure is further described by the following embodiments. Configuration 1: A cylindrical battery comprising a wound electrode assembly, a cylindrical outer can housing the electrode assembly, a sealing body closing an opening of the outer can, and an insulating member arranged axially outward of the electrode assembly, the insulating member having at least one or more protrusions. Configuration 2: The cylindrical battery according to Configuration 1, wherein the insulating member abuts against the electrode assembly. Configuration 3: The cylindrical battery according to Configuration 1 or 2, wherein the sealing body is fixed to the opening of the outer can by crimping via the insulating member. Configuration 4: The cylindrical battery according to any one of Configurations 1 to 3, wherein the protrusions protrude toward the sealing body side or the electrode assembly side. Configuration 5: The cylindrical battery according to any one of Configurations 1 to 4, wherein the protrusions extend radially outward from a central portion of the insulating member. Configuration 6: The cylindrical battery according to any one of Configurations 1 to 5, wherein the insulating member has a plurality of the protrusions, and the plurality of protrusions are arranged at approximately equal angular intervals in the circumferential direction of the outer can.Configuration 7: The cylindrical battery according to any one of Configurations 1 to 6, wherein the height of the protrusions is 50% or more of the distance from the end of the electrode assembly facing the sealing body to the end of the sealing body facing the electrode assembly.Configuration 8: The cylindrical battery according to any one of Configurations 1 to 7, further comprising an electrode lead connected to an electrode constituting the electrode assembly, wherein the insulating member has a plurality of through holes, and the electrode lead passes through at least one of the plurality of through holes.Configuration 9: The cylindrical battery according to Configuration 8, wherein the electrode lead does not pass through at least one of the plurality of through holes. Configuration 10: The cylindrical battery according to any one of Configurations 1 to 9, wherein the insulating member has an outer peripheral portion that sandwiches the sealing body from both sides in the axial direction, an inner peripheral portion that is disposed opposite the surface of the electrode body facing the sealing body, and a connecting portion that connects the outer peripheral portion and the inner peripheral portion.Configuration 11: The cylindrical battery according to Configuration 10, wherein the insulating member has a plurality of the connecting portions.Configuration 12: The cylindrical battery according to Configuration 11, wherein the plurality of connecting portions are provided at approximately equal angular intervals in the circumferential direction of the outer can.Configuration 13: The cylindrical battery according to any one of Configurations 10 to 12, wherein the insulating member is provided with a groove portion that extends along the circumferential direction of the outer can.Aspect 14: The cylindrical battery according to any one of Aspects 1 to 13, further comprising: an electrode lead connected to an electrode constituting the electrode body; and a current collecting member to which the electrode lead is joined and which electrically connects the electrode lead and the sealing body, wherein the insulating member is provided with a fixing portion for fixing the insulating member and the current collecting member. Aspect 15: The cylindrical battery according to any one of Aspects 1 to 14, wherein the outer can has an opening at its bottom.

[0073] 10, 10X, 10Y, 10Z Cylindrical battery, 11 Positive electrode, 12 Negative electrode, 12A Negative electrode core exposed portion, 13 Separator, 14 Electrode body, 16 Outer can, 17 Sealing body, 18 Lower insulating plate, 20 Positive electrode lead (electrode lead), 21 Negative electrode lead (electrode lead), 22 Grooved portion, 23 Upper terminal plate, 24 Sealing plate, 25 Gasket, 26 Rivet, 27 Lower sealing plate, 28 Lower terminal plate, 29 Gasket, 30 Insulating member, 30A Through hole, 31 Base portion, 32 Convex portion, 33 Outer periphery, 34 Inner periphery, 35 Connecting portion, 36 First through hole, 37 Second through hole, 38 Third through hole, 39 Fourth through hole, 40 Fixing portion, 41 First groove portion, 42 Second groove portion, 43 Third groove portion, 50 current collecting member, 50A through hole, 51 first region, 52 second region

Claims

1. A cylindrical battery comprising a wound electrode body, a cylindrical outer can housing the electrode body, a sealing body closing an opening of the outer can, and an insulating member disposed axially outside the electrode body, wherein the insulating member has at least one or more convex portions.

2. The cylindrical battery according to claim 1, wherein the insulating member is in contact with the electrode body.

3. The cylindrical battery according to claim 1, wherein the sealing body is caulked and fixed to the opening of the outer can via the insulating member.

4. The cylindrical battery according to claim 1, wherein the convex portion protrudes toward the sealing body side or the electrode body side.

5. The cylindrical battery according to claim 1, wherein the convex portion extends radially outward from the central portion side of the insulating member.

6. The cylindrical battery according to claim 1, wherein the insulating member has a plurality of the convex portions, and the plurality of the convex portions are arranged at substantially equal angular intervals in the circumferential direction of the outer can.

7. The cylindrical battery according to claim 1, wherein a height of the convex portion is 50% or more of a distance from an end portion of the electrode body on the sealing body side to an end portion of the sealing body on the electrode body side.

8. The cylindrical battery according to claim 1, further comprising an electrode lead connected to an electrode constituting the electrode body, wherein the insulating member is provided with a plurality of through holes, and at least one of the plurality of through holes allows the electrode lead to pass through.

9. The cylindrical battery according to claim 8, wherein at least one of the plurality of through holes does not allow the electrode lead to pass through.

10. The cylindrical battery according to claim 1, wherein the insulating member has an outer peripheral portion sandwiching the sealing body from both axial sides, an inner peripheral portion disposed opposite to a surface of the electrode body on the sealing body side, and a connecting portion connecting the outer peripheral portion and the inner peripheral portion.

11. The cylindrical battery according to claim 10, wherein the insulating member has a plurality of the connecting portions.

12. The cylindrical battery according to claim 11, wherein the plurality of the connecting portions are provided at substantially equal angular intervals in the circumferential direction of the outer can.

13. The cylindrical battery according to claim 1, wherein the insulating member is provided with a groove portion extending along the circumferential direction of the outer can.

14. An electrode lead connected to the electrode constituting the electrode body, a current collecting member to which the electrode lead is joined and which electrically connects the electrode lead and the sealing body, and further comprising: the insulating member is provided with a fixing portion for fixing the insulating member and the current collecting member. The cylindrical battery according to claim 1.

15. The cylindrical battery according to claim 1, wherein the outer can has an opening at the bottom.

Images