Sealed battery

Abstract

The purpose of the present disclosure is to provide a sealed battery that has a simplified and low-cost structure and can more reliably cut off the current path when an abnormality occurs in the battery. A sealed battery as an example of an embodiment comprises: an electrode body to which an electrode connector is connected; a bottomed cylindrical outer can that accommodates the electrode body; and a sealing body that blocks the opening of the outer can. The sealing body includes a bursting plate. The bursting plate has a first valve portion surrounded by a curved first thin-walled portion and a straight portion connecting the two ends of the first thin-walled portion. The first valve portion has a convex portion protruding toward the electrode body, the electrode connector is joined to the side of the convex portion, and at least a portion of the joining surface of the electrode connector and the protrusion is arranged on a plane intersecting the straight portion.

Description

Technical Field

[0001] The present disclosure relates to sealed batteries. Background Art

[0002] In the past, it is well known that a sealed battery includes a battery case including an outer can with a bottom and a sealing body that blocks the opening of the outer can. For example, Patent Document 1 discloses a cylindrical sealed battery, which includes a sealing body composed of a metal plate having a convex shape convex to the inside of the battery case. Patent Document 1 states that when an abnormality occurs in the battery, the sealing body flips over, and the weld between the sealing body and the collector is broken, thereby cutting off the current and ensuring safety.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-269904 Summary of the invention

[0006] -Problems to be solved by the invention-

[0007] In recent years, in the process of developing sealed batteries with high energy density, more attention has been paid to safety when abnormalities occur, and battery designs that can reliably cut off the battery's current path when abnormalities occur are sought. However, on the other hand, there is a great demand for lower-priced batteries, and cost reductions brought about by simplified structures and reduced number of parts have become necessary.

[0008] -Methods for solving problems-

[0009] A sealed battery in one embodiment of the present invention comprises: an electrode body connected to an electrode connector; a bottomed cylindrical outer can that accommodates the electrode body; and a sealing body that blocks the opening of the outer can, the sealing body including a bursting plate, the bursting plate having a first valve portion surrounded by a curved first thin-walled portion and a straight portion connecting both ends of the first thin-walled portion, the first valve portion having a convex portion protruding toward the electrode body, the electrode connector being joined to a side surface of the convex portion, and at least a portion of a joining surface between the electrode connector and the convex portion being arranged on a plane intersecting the straight portion.

[0010] Another embodiment of a sealed battery disclosed herein comprises: an electrode body connected to an electrode terminal; a bottomed cylindrical outer can that accommodates the electrode body; and a sealing body that blocks the opening of the outer can, the sealing body comprising a bursting plate and a connecting member between the bursting plate and the electrode terminal, the bursting plate having a first valve portion surrounded by a curved first thin-walled portion and a straight portion connecting both ends of the first thin-walled portion, the first valve portion having a convex portion protruding toward the electrode body, the connecting member being joined to a side surface of the convex portion, the electrode terminal being joined to a side surface of the connecting member, and at least a portion of at least one of a first joining surface between the convex portion and the connecting member and a second joining surface between the electrode terminal and the connecting member being arranged on a plane intersecting the straight portion.

[0011] -Effects of the Invention-

[0012] According to the present disclosure, it is possible to provide a sealed battery that has a simplified and low-cost structure and can more reliably cut off a current path when a battery abnormality occurs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a cross-sectional view of a sealed battery as an example of an embodiment.

[0014] Figure 2 This is a perspective view of a sealing body as an example of the embodiment as viewed from the inner surface side.

[0015] Figure 3 It is a bottom view of the sealing body as an example of embodiment.

[0016] Figure 4 yes Figure 3 AA line section view in.

[0017] Figure 5 This is a diagram showing a state in which a valve portion of a sealing body is opened as an example of an embodiment.

[0018] Fig. 6A It is a cross-sectional view showing a modified example of the sealing body.

[0019] Figure 6B It is a cross-sectional view showing a modified example of the sealing body.

[0020] Fig. 7A It is a diagram for explaining a method for manufacturing a sealed battery as an example of an embodiment.

[0021] Figure 7B It is a diagram for explaining a method for manufacturing a sealed battery as an example of an embodiment. DETAILED DESCRIPTION

[0022] Hereinafter, an example of an embodiment of the present disclosure will be described in detail. Hereinafter, as an example of an embodiment of a sealed battery involved in the present disclosure, a cylindrical battery 10 in which a wound electrode body 11 is housed in an outer can 12 having a bottom and a cylindrical shape is illustrated, and the battery may also be a square battery having an outer can 12 having a bottom and a square cylindrical shape. In addition, the electrode body may also be a stacked type in which a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked via separators. In this specification, for the sake of convenience of description, the sealing body 13 side of the battery case including the outer can 12 and the sealing body 13 is described as the "upper" and the bottom side of the outer can 12 is described as the "lower".

[0023] Figure 1 FIG. 1 is a cross-sectional view of a cylindrical battery 10 as an example of an embodiment. Figure 1 As shown in the example, the cylindrical battery 10 is a cylindrical sealed battery, which includes: an electrode body 11 connected to an electrode tab; a bottomed cylindrical outer can 12 that accommodates the electrode body 11; and a sealing body 13 that blocks the opening of the outer can 12. In this embodiment, a groove 16 that protrudes toward the inside of the outer can 12 is formed at the upper end of the outer can 12, and the sealing body 13 is fixed to the upper end of the outer can 12 by riveting via an insulating gasket 14. The outer can 12 and the sealing body 13 are both made of metal, and thus are insulated by the gasket 14.

[0024] The electrode body 11 has a winding structure in which the positive electrode and the negative electrode are wound into a spiral shape via a separator. The positive electrode, the negative electrode and the separator are all strip-shaped long strips. The positive electrode connector 15 is connected to the positive electrode, and the negative electrode connector (not shown) is connected to the negative electrode by welding or the like. In the present embodiment, the strip-shaped positive electrode connector 15 connected to the central part of the long side direction of the positive electrode extends from the upper end of the electrode body 11 and is connected to the sealing body 13. The negative electrode connector is connected to at least one of the end portion of the winding start side and the end portion of the winding end side of the negative electrode, and is connected to the bottom inner surface of the outer can 12. In this case, the sealing body 13 becomes the positive electrode external terminal, and the outer can 12 becomes the negative electrode external terminal. In addition, the negative electrode connector can be connected to the sealing body 13, and the positive electrode connector 15 can be connected to the outer can 12.

[0025] The positive electrode has a positive electrode core and a positive electrode mixture layer formed on the surface of the positive electrode core. The positive electrode core can be made of a foil of a metal such as aluminum or aluminum alloy that is stable in the potential range of the positive electrode, or a film that configures the metal on the surface. The positive electrode mixture layer includes a positive electrode active material, a conductive agent such as acetylene black, and a binder such as polyvinylidene fluoride (PVdF), and is preferably formed on both sides of the positive electrode core except for the portion connected to the positive electrode terminal 15. For example, a lithium transition metal composite oxide is used as the positive electrode active material.

[0026] The negative electrode has a negative electrode core and a negative electrode mixture layer formed on the surface of the negative electrode core. The negative electrode core can use a foil of a metal such as copper or copper alloy that is stable within the potential range of the negative electrode, a film that configures the metal on the surface, etc. The negative electrode mixture layer preferably includes a negative electrode active material and a binder such as styrene-butadiene rubber (SBR), and is formed on both sides of the negative electrode core except for the portion connected to the negative electrode connector. The negative electrode active material uses, for example, a carbon-based active material such as graphite, a Si-based active material containing Si, etc. In addition, it is also possible to provide a current collection structure in which the surface of the negative electrode core is in contact with the inner circumferential surface of the outer can 12 instead of connecting the negative electrode connector to the negative electrode.

[0027] An insulating plate 17 is arranged between the bottom inner surface of the outer can 12 and the electrode body 11 to prevent the positive electrode of the electrode body 11 from making electrical contact with the outer can 12. The negative electrode terminal, for example, passes through the gap between the outer can 12 and the insulating plate 17 and extends to the bottom side of the outer can 12. In addition, an insulating separator 18 is arranged between the sealing body 13 and the electrode body 11. The separator 18 prevents the negative electrode of the electrode body 11 from making electrical contact with the sealing body 13, and adjusts the interval between the electrode body 11 and the sealing body 13. Although it will be described in detail later, it is preferred that the positive electrode terminal 15 is not bent but is in a taut state so that the current path can be easily cut off when an abnormality occurs. The positive electrode terminal 15 passes through the through hole 18a of the separator 18 and extends to the sealing body 13 side.

[0028] The outer can 12 contains the electrode body 11 and the electrolyte. Although the electrolyte may also be an aqueous electrolyte, it is preferably a non-aqueous electrolyte. The non-aqueous electrolyte includes, for example, a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. The non-aqueous solvent uses esters, ethers, nitrile rubbers, amides, and mixed solvents of two or more of these solvents. The non-aqueous solvent may also contain a halogen substitution body in which at least a portion of the hydrogen of these solvents is replaced with a halogen atom such as fluorine. In addition, the non-aqueous electrolyte is not limited to a liquid electrolyte, but may also be a solid electrolyte. The electrolyte salt uses a lithium salt such as LiPF6.

[0029] Below, refer to Figure 2 to Figure 4 , the structure of the sealing body 13 and the connection structure between the sealing body 13 and the positive electrode terminal 15 are described in detail. Figure 2 This is a perspective view of the sealing body 13 as viewed from the inner surface side. Figure 3 is a bottom view of the sealing body 13, Figure 4 yes Figure 3 AA line section view in.

[0030] like Figure 2 to Figure 4As shown in the example, the sealing body 13 includes: a bursting plate 20 including a valve portion 24; a convex portion 22 protruding from the inner surface of the valve portion 24 to the electrode body 11 side; and a connecting member 25 joined to the convex portion 22. The inner surface of the bursting plate 20 (valve portion 24) means the surface facing the electrode body 11 side. The bursting plate 20 is composed of a metal plate having a thin wall portion 21 formed thereon that breaks when the internal pressure of the battery reaches a predetermined pressure. An example of a preferred metal plate is an aluminum plate or an aluminum alloy plate having aluminum as a main component.

[0031] The bursting plate 20 has a shape and size that can block the opening of the outer can 12. The bursting plate 20 is, for example, a circular plate in a perfect circular shape when viewed from above. In the present embodiment, an annular groove is formed on the inner surface of the bursting plate 20, and a portion of the groove is thinner than other portions to form a thin-walled portion 21 that is preferentially broken when the internal pressure of the battery rises. The thin-walled portion 21 is formed in a shape (perfect circular shape when viewed from above) concentric with the circumferential circle of the bursting plate 20 with a diameter smaller than that of the bursting plate 20. The thin-walled portion 21 does not necessarily have to be formed in a perfect circular shape, but is preferably formed in an annular shape.

[0032] Although the thickness of the bursting plate 20 is not particularly limited, as an example, the thickness of the portion other than the thin-walled portion 21 and the convex portion 22 is 0.3 mm to 2 mm. The thickness of the thin-walled portion 21 is, for example, 10% to 50% of the thickness of the valve portion 24. The thin-walled portion 21 may be formed with the same thickness over the entire length, but in this embodiment, the first thin-walled portion 21A and the second thin-walled portion 21B, each formed in an arc shape, are connected to form a circular ring. The first thin-walled portion 21A and the second thin-walled portion 21B are both formed by a groove having a substantially V-shaped cross section, but the residual wall thickness of the first thin-walled portion 21A is smaller than the residual wall thickness of the second thin-walled portion 21B.

[0033] The portion surrounded by the thin-walled portion 21 of the bursting plate 20 is the valve portion 24 that opens to the outside of the battery due to the rupture of the thin-walled portion 21. The valve portion 24 opens when the internal pressure of the battery reaches a given working pressure (pressure at which the thin-walled portion 21 ruptures) due to an abnormality in the battery, and discharges the gas inside the battery, thereby preventing the outer can 12 from rupturing. In the present embodiment, a valve portion 24 that is a perfect circle when viewed from above is formed in a portion other than the peripheral portion of the bursting plate 20. Moreover, the valve portion 24 includes two valve portions (a first valve portion 24A and a second valve portion 24B). The thin-walled portion 21 is preferably a continuous curved shape throughout the entire range, but a portion of the thin-walled portion 21 may be discontinuous within a range that does not hinder the operation of the valve portion 24. In addition, Figure 3 The first valve portion 24A and the second valve portion 24B are shown to have the same area when viewed from below, but may have different areas.

[0034] The first valve portion 24A is a portion surrounded by the first thin-walled portion 21A and a straight line α connecting the two ends thereof, and is formed in a semicircular shape when viewed from above. Similarly, the second valve portion 24B is a portion surrounded by the arc of the second thin-walled portion 21B and a straight line α connecting the two ends thereof, and is formed in a semicircular shape when viewed from above. The first thin-walled portion 21A and the second thin-walled portion 21B only need to be formed in a curved shape when viewed from above. The first thin-walled portion 21A and the second thin-walled portion 21B are preferably curved shapes that bulge toward the outer periphery of the bursting plate 20, and more preferably in an arc shape.

[0035] Since the remaining wall thickness of the first thin-walled portion 21A is smaller than the remaining wall thickness of the second thin-walled portion 21B, when the internal pressure of the battery reaches a given pressure, the first valve portion 24A breaks preferentially over the second valve portion 24B. Figure 5 As shown, the first valve portion 24A opens outward with the straight line α as the rotation axis. As described later in detail, by opening the first valve portion 24A, the gas is discharged, and the connection between the sealing body 13 and the positive electrode connector 15, which also functions as the positive electrode external terminal, is cut off, and the current path of the battery is cut off. In addition, in order to facilitate the rotation of the first valve portion 24A, a crease line and a shallow groove may also be formed along the straight line α. The valve portion 24 may also be composed of only the first valve portion 24A, but by combining the second valve portion 24B with the first valve portion 24A, the gas discharge capacity of the valve portion 24 can be improved. Therefore, the valve portion 24 preferably also has a second valve portion 24B together with the first valve portion 24A.

[0036] As described above, the convex portion 22 is a protrusion formed on the inner surface of the valve portion 24, and is formed in an annular shape along the peripheral edge of the valve portion 24. The convex portion 22 is a portion for fixing the connecting member 25, and can fix the connecting member 25 by welding or the like, and is formed with a protruding length that does not interfere with the electrode body 11. The convex portion 22 has, for example, a side surface along the up-down direction, and a first bonding surface 26 with the connecting member 25 is formed on the side surface.

[0037] In this specification, the side surfaces of the protrusion 22 and the connecting member 25 refer to surfaces facing in a direction intersecting the surface direction of the blasting panel 20 , for example, surfaces inclined at an angle of 45° or less with respect to the vertical direction perpendicular to the surface direction of the blasting panel 20 .

[0038] The convex portion 22 is provided with two slits 23 arranged in the radial direction of the burst plate 20 at a position overlapping with the rotation axis of the first valve portion 24A, that is, the straight line α dividing the first valve portion 24A and the second valve portion 24B. The two slits 23 separate the convex portion 22 into a first portion formed in the first valve portion 24A and a second portion formed in the second valve portion 24B. Thus, the first valve portion 24A is easily opened so as to rotate with the straight line α as the rotation axis.

[0039] The connecting member 25 is a conductive member that electrically connects the positive electrode terminal 15 and the valve portion 24. The side surface of one end is joined to the side surface of the protrusion 22, and the side surface of the other end is joined to the positive electrode terminal 15. Moreover, at least a portion of at least one of the first joint surface 26 of the protrusion 22 and the connecting member 25, and the second joint surface 27 of the positive electrode terminal 15 and the connecting member 25 is arranged on a plane intersecting the straight line α. Therefore, when the first thin-walled portion 21A is opened to rotate with the straight line α as the rotation axis, a rotational shear force acts on at least one of the first joint surface 26 and the second joint surface 27. The first joint surface 26 and the second joint surface 27 are formed, for example, by laser welding.

[0040] In the present embodiment, one end of the connecting member 25 is connected to the position farthest from the straight line α that becomes the rotation axis in the first part formed in the first valve portion 24A, which is the convex portion 22. One end of the connecting member 25 has a shape bent along the side of the convex portion 22 formed in an annular shape, and the first bonding surface 26 is formed along the side of the convex portion 22. The central part of the first bonding surface 26 in the circumferential direction of the convex portion 22 is arranged on a plane intersecting with the rotation axis (straight line α) of the first valve portion 24A. Therefore, although the shear force acts in the up and down directions at the central part of the first bonding surface 26 when the first valve portion 24A is opened, the rotational shear force does not act.

[0041] On the other hand, both ends of the first joint surface 26 in the circumferential direction of the convex portion 22 are arranged on a plane intersecting the rotation axis of the first valve portion 24A. Therefore, at both ends of the first joint surface 26, when the first valve portion 24A is opened, a rotational shear force acts on the joint surface. That is, if at least a portion of the first joint surface 26 is arranged on a plane intersecting the rotation axis of the first valve portion 24A, a rotational shear force acts when the first valve portion 24A is opened.

[0042] When viewed from above, the connecting member 25 has a shape that gradually expands toward one end portion joined to the side surface of the protrusion 22. The other end portion of the connecting member 25 is thinner than the one end portion, and extends along the radial direction of the bursting plate 20 (valve portion 24) in a state where the side surface of the one end portion is joined along the side surface of the protrusion 22. The connecting member 25 extends from the vicinity of the first thin wall portion 21A of the first valve portion 24A to the vicinity of the rotation axis of the first valve portion 24A, and is joined to the sealing body 13 only at the first joining surface 26.

[0043] The positive electrode terminal 15 is joined to the side surface of the other end of the connecting member 25. In the present embodiment, the positive electrode terminal 15 and the second joining surface 27 of the connecting member 25 are arranged as a whole on a plane substantially orthogonal to the rotation axis of the first valve portion 24A. Therefore, when the first valve portion 24A is opened, a large rotational shear force acts on the second joining surface 27. As with the first joining surface 26, it is sufficient as long as at least a portion of the second joining surface 27 is arranged on a plane intersecting the rotation axis of the first valve portion 24A. However, it is preferred that the entire second joining surface 27 is arranged on a plane intersecting the rotation axis of the first valve portion 24A, and it is more preferred that it is arranged on a plane orthogonal to the rotation axis of the first valve portion 24A as in the present embodiment.

[0044] In addition, the first joint surface 26 is formed near the first thin-walled portion 21A, but the second joint surface 27 is formed near the rotation axis of the first valve portion 24A closer to the first thin-walled portion 21A. The second joint surface 27 is formed, for example, along the radial direction of the valve portion 24 with a fixed width, from the center of the first valve portion 24A to the vicinity of the rotation axis of the first valve portion 24A (see Figure 2 In order to prevent interference with the second valve portion 24B, the connecting member 25 has a length such that the other end portion thereof is close to the rotation axis within a range not exceeding the rotation axis of the first valve portion 24A.

[0045] like Figure 5 As shown in FIG. 1 , when the first valve portion 24A is opened, the rotational shear force also acts on a portion of the first joint surface 26 between the convex portion 22 and the connecting member 25, and the rotational shear force acts on the entire second joint surface 27 arranged on a plane orthogonal to the rotation axis of the first valve portion 24A. Figure 4 In the cross-sectional view shown, the second lever is formed with the rotation axis as the fulcrum, the first thin wall portion 21A as the force point, and the second joint surface 27 as the action point, and a large force acts on the second joint surface 27. Therefore, the second joint surface 27 can be broken more easily than the first joint surface 26.

[0046] As described above, according to the cylindrical battery 10 having the above structure, it is a simplified low-cost structure, and when an abnormality of the battery occurs, the second joint surface 27 can be easily removed with the opening of the first valve portion 24A, and the current path can be more reliably cut off. For example, by laser welding, the welding strength of the second joint surface 27 formed with a width of about 0.5 mm and a length of about 2.5 mm relative to the up and down directions is more than 30N, but the torque strength is about 20N·mm. Therefore, for a point 5mm away from the second joint surface 27, if the stress in the direction of rotating the joint surface acts, the joint surface breaks with a force of 4N. In addition, in the conventional ordinary sealed batteries, a joint surface with the electrode terminal is formed on the bottom surface of the sealing body along the surface direction. In order to make the tensile stress in the direction perpendicular to the joint surface act and break the joint surface, a force exceeding 30N of the welding strength is required.

[0047] Fig. 6A and Figure 6B 13 is a cross-sectional view showing a modified example (sealing bodies 13X, 13Y) of the sealing body 13. In the above-mentioned sealing body 13, an annular convex portion 22 is formed on the inner surface of the first valve portion 24A and the second valve portion 24B. Fig. 6A The sealing body 13X shown is formed with a convex portion 22X having the same width as one end of the connecting member 25 and having an arc shape when viewed from above. The convex portion 22X is formed only in the first valve portion 24A and is gently curved along the first thin-walled portion 21A formed in an arc shape. In addition, the convex portion 22X may also be formed in a flat plate shape along the rotation axis of the first valve portion 24A.

[0048] Figure 6B The sealing body 13Y shown is different from the sealing body 13 in that it does not have a connecting member and directly joins the positive electrode tab 15 to the side of the protrusion 22Y. The side of the protrusion 22Y is formed flat and is arranged on a plane perpendicular to the rotation axis of the first valve portion 24A. As a result, the first thin-walled portion 21A is broken at the joining surface 27Y formed on the side of the protrusion 22Y with the positive electrode tab 15, and a large rotational shear force acts when the first valve portion 24A is opened.

[0049] Fig. 7A and Figure 7B 1 is a diagram showing the manufacturing process of the cylindrical battery 10. Fig. 7A As shown in the figure, the manufacturing process of the cylindrical battery 10 includes a process of joining the positive electrode tab 15 connected to the electrode body 11 to the sealing body 13. The positive electrode tab 15 is joined to the side surface of the other end of the connecting member 25 by laser welding or the like. In addition, one end of the connecting member 25 is joined to the side surface of the convex portion 22 of the sealing body 13 by laser welding or the like. In addition, the annular gasket 14 is mounted on the peripheral portion of the bursting plate 20 of the sealing body 13.

[0050] Next, if Figure 7B As shown in the figure, the electrode body 11 and the electrolyte are housed in the outer can 12, with the separator 18 inserted between the electrode body 11 and the sealing body 13, and the sealing body 13 is arranged inside the opening of the outer can 12 so that the opening at the upper end of the outer can 12 is blocked by the sealing body 13. In this state, the outer can 12 is riveted from the outside in the radial direction of the sealing body 13, so that the opening of the outer can 12 is blocked by the sealing body 13 via the gasket 14, and the outer can 12 is obtained. Figure 1 The cylindrical battery 10 is shown in FIG. 1 . In addition, an insulating plate 17 is disposed between the electrode body 11 and the bottom inner surface of the outer can 12 .

[0051] As described above, the separator 18 prevents the negative electrode of the electrode body 11 from being in electrical contact with the sealing body 13, and adjusts the interval between the electrode body 11 and the sealing body 13 so that the positive electrode terminal 15 is not bent but is tightened. If the positive electrode terminal 15 is in an unbent state, the rotational shear force is not absorbed by the bent portion and is easily applied to the second joint surface 27 of the positive electrode terminal 15 and the connecting member 25.

[0052] -Explanation of symbols-

[0053] 10 cylindrical battery, 11 electrode body, 12 outer can, 13, 13X, 13Y sealing body, 14 gasket, 15 positive electrode terminal, 16 groove portion, 17 insulating plate, 18 separator, 18a through hole, 20 bursting plate, 21 thin-walled portion, 21A first thin-walled portion, 21B second thin-walled portion, 22, 22X, 22Y convex portion, 23 slit, 24 valve portion, 24A first valve portion, 24B second valve portion, 25 connecting member, 26 first joint surface, 27 second joint surface.

Claims

1. A sealed battery comprising: an electrode body connected to an electrode terminal; a bottomed cylindrical outer can accommodating the electrode body; and a sealing body for blocking an opening of the outer can, The sealing body comprises a bursting plate, The bursting plate includes a first valve portion surrounded by a curved first thin-walled portion and a straight portion connecting both ends of the first thin-walled portion. The first valve portion has a convex portion protruding toward the electrode body, The electrode connector is connected to the side surface of the protrusion. At least a portion of the bonding surface between the electrode tab and the protrusion is arranged on a plane intersecting the straight line portion. The first valve portion opens outward with the straight portion as a rotation axis, thereby interrupting the current path.

2. The sealed battery according to claim 1, wherein: The bonding surface is arranged on a plane perpendicular to the straight line.

3. A sealed battery comprising: an electrode body connected to an electrode terminal; a bottomed cylindrical outer can accommodating the electrode body; and a sealing body for blocking an opening of the outer can, The sealing body includes a bursting plate and a connecting member between the bursting plate and the electrode connector. The bursting plate includes a first valve portion surrounded by a curved first thin-walled portion and a straight portion connecting both ends of the first thin-walled portion. The first valve portion has a convex portion protruding toward the electrode body, The connecting member is engaged with the side surface of the convex portion, The electrode connector is connected to the side surface of the connecting member. At least a portion of at least one of the first joining surface of the protrusion and the connecting member and the second joining surface of the electrode tab and the connecting member is arranged on a plane intersecting the straight portion, The first valve portion opens outward with the straight portion as a rotation axis, thereby interrupting the current path.

4. The sealed battery according to claim 3, wherein: At least one of the first bonding surface and the second bonding surface is arranged on a plane orthogonal to the straight line.

5. The sealed battery according to any one of claims 1 to 4, wherein The first thin-walled portion has a curved shape that is convex toward an outer peripheral portion of the bursting panel.

6. The sealed battery according to any one of claims 1 to 4, wherein The bursting plate includes an annular thin-walled portion formed by the first thin-walled portion and a curved second thin-walled portion connected to both ends of the first thin-walled portion. The remaining wall thickness of the first thin-walled portion is smaller than the remaining wall thickness of the second thin-walled portion.

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