Gasket for cylindrical battery, cylindrical battery, and method for manufacturing the same

Abstract

The gasket (28) has: a cylindrical tubular portion (29); and a circular ring portion (30) extending to the inner side in the radial direction from the end portion on one side in the axial direction of the tubular portion (29). The tubular portion (29) has a protruding portion (31) protruding to the inner side in the radial direction between both end portions in the axial direction. The protruding portion (31) has: a first inclined portion on the side of the circular ring portion (30); and a second inclined portion on the opposite side of the circular ring portion (30), the first inclined portion being formed so as not to exceed the top surface (39) of the flange portion of the closure body (17) in the case where the closure body (17) is arranged on the circular ring portion (30).

Description

Technical Field

[0001] This disclosure relates to a gasket for a cylindrical battery, a method for manufacturing a cylindrical battery using the gasket, and a cylindrical battery. Background Technology

[0002] A cylindrical battery comprises: a bottomed cylindrical outer can; a sealing body that blocks the opening of the outer can; and a gasket between the outer can and the sealing body. In the outer can, the edge of the opening is bent inwards, forming a rivet joint that secures the sealing body to the outer can via the gasket. In the manufacturing process of the cylindrical battery, the sealing body is sometimes used with the gasket attached. To prevent the sealing body from detaching from the gasket before the rivet joint is formed, a protrusion is generally provided on the inner side of the gasket to cover the flange of the sealing body. For example, a gasket with a protrusion is disclosed in Patent Document 1.

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: JP Japanese Patent Application Publication No. 2000-260409 Summary of the Invention

[0006] -The problem the invention aims to solve-

[0007] In existing gaskets with protrusions, during the formation of the riveting section, the edge of the outer can presses the gasket inward, and the protrusions of the gasket easily climb onto the flange of the sealing body. If the protrusion climbs onto the flange of the sealing body and is pushed radially inward, the portion of the gasket other than the protrusion will be pulled by the protrusion and flow radially inward into the sealing body. As a result, the thickness of the portion of the gasket that abuts against the sealing body becomes thinner, sometimes creating a gap between the gasket and the outer can. If a gap exists between the gasket and the outer can, there is a possibility of electrolyte leakage from inside the battery when the gasket repeatedly expands and contracts due to changes in ambient temperature.

[0008] The purpose of this disclosure is to provide a gasket for a cylindrical battery, a method for manufacturing a cylindrical battery using the same, and a cylindrical battery that makes it difficult to create a gap between the gasket and the outer can when forming the riveted part, resulting in high airtightness.

[0009] -Methods used to solve problems-

[0010] The cylindrical battery gasket disclosed herein includes: a cylindrical portion; and an annular portion extending from one axial end of the cylindrical portion to a radially inward side. The cylindrical portion has a protrusion protruding radially inward between its two axial ends. The protrusion has: a first inclined portion located on the side of the annular portion; and a second inclined portion located on the side of the cylindrical portion further axially than the first inclined portion. When a sealing body is disposed on the annular portion, the first inclined portion is formed at a position not exceeding the top surface of the flange portion of the sealing body.

[0011] A method for manufacturing a cylindrical battery using the gasket disclosed herein includes the following steps: equipping a gasket to a sealing body such that the sealing body is disposed on an annular portion; disposing the gasket on a groove formed by extending inward from a side near the opening in a bottomed cylindrical outer can; and bending the edge of the opening of the outer can inward to form a riveting portion, thereby compressing the gasket and the outer can in the sealing body.

[0012] A cylindrical battery having the gasket involved in this disclosure comprises: a bottomed cylindrical outer can; and a sealing body disposed on the annular portion of the gasket, the sealing body being riveted to the outer can through the gasket.

[0013] -Invention Effects-

[0014] According to the gasket involved in this disclosure, it is possible to achieve a cylindrical battery with high sealing performance, which makes it difficult to generate gaps between the gasket and the outer can. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of a cylindrical battery, which is an example of an embodiment of this disclosure.

[0016] Figure 2 This is a cross-sectional view showing the state of the sealing body equipped with the gasket of the embodiment, which is supported by the groove of the outer can.

[0017] Figure 3 This is an enlarged cross-sectional view of the main part of the gasket in the embodiment.

[0018] Figure 4 This is a cross-sectional view of the riveting portion of a cylindrical battery utilizing the padding of the embodiment.

[0019] Figure 5 This is a cross-sectional view showing the state of the sealing body equipped with the gasket of the comparative example, which is supported by the groove of the outer can.

[0020] Figure 6 This is a cross-sectional view of the riveting part of a cylindrical battery that utilizes the padding of the comparative example. Detailed Implementation

[0021] Hereinafter, embodiments of the cylindrical battery according to this disclosure will be described in detail with reference to the accompanying drawings. The cylindrical battery of this disclosure can be a primary battery or a secondary battery. Furthermore, it can be a battery utilizing an aqueous electrolyte or a battery utilizing a non-aqueous electrolyte. Hereinafter, a cylindrical battery utilizing a non-aqueous electrolyte (e.g., a lithium-ion battery) will be illustrated as an example of an embodiment, but the cylindrical battery of this disclosure is not limited to this.

[0022] Figure 1 This is a cross-sectional view of a cylindrical battery 10, as an example of an embodiment. Figure 1 As shown, the cylindrical battery 10 includes: a wound electrode body 14; a non-aqueous electrolyte; and an outer casing 16 for housing the electrode body 14 and the non-aqueous electrolyte. The electrode body 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 wound in a spiral shape with the separator 13 in between. The outer casing 16 is a bottomed cylindrical metal container with an opening on one side of the axial direction, and the opening of the outer casing 16 is blocked by a sealing body 17. Hereinafter, for ease of explanation, the sealing body 17 side of the battery will be referred to as the upper side, and the bottom side of the outer casing 16 will be referred to as the lower side.

[0023] The positive electrode 11, negative electrode 12, and spacer 13 constituting the electrode body 14 are all strip-shaped elongated bodies, which are alternately stacked in the radial direction of the electrode body 14 by spiral winding. To prevent lithium deposition, the negative electrode 12 is formed to be one size larger than the positive electrode 11. That is, the negative electrode 12 is formed to be longer than the positive electrode 11 in both the long side direction and the width direction (short side direction). Two spacers 13 are formed to be at least one size larger than the positive electrode 11, for example, configured to sandwich the positive electrode 11. The electrode body 14 includes: a positive electrode lead 20 connected to the positive electrode 11 by welding or the like; and a negative electrode lead 21 connected to the negative electrode 12 by welding or the like.

[0024] Insulating plates 18 and 19 are respectively disposed above and below the electrode body 14. Figure 1 In the example shown, the positive lead 20 extends through the through hole in the insulating plate 18 to the side of the sealing body 17, and the negative lead 21 extends through the outside of the insulating plate 19 to the bottom side of the outer can 16. The positive lead 20 is connected to the lower surface of the internal terminal plate 23 of the sealing body 17 by welding or the like, and the top plate, i.e., the cap 27, of the sealing body 17, which is electrically connected to the internal terminal plate 23, becomes the positive terminal. The negative lead 21 is connected to the inner bottom surface of the outer can 16 by welding or the like, and the outer can 16 becomes the negative terminal.

[0025] A gasket 28 is provided between the outer can 16 and the sealing body 17 to ensure the airtightness of the battery interior. A groove 22 is formed on the outer can 16, extending inward from a portion of its side surface to support the sealing body 17. The groove 22 is preferably formed in a circumferential shape along the outer can 16, and the sealing body 17 is supported on its upper surface by the gasket 28. The sealing body 17 is fixed to the upper part of the outer can 16 by the groove 22 and the open end of the outer can 16 riveted to the sealing body 17.

[0026] The sealing body 17 has a structure in which an internal terminal plate 23, a lower valve body 24, an insulating member 25, an upper valve body 26, and a cap 27 are stacked sequentially from the electrode body 14 side. Each component constituting the sealing body 17 has, for example, a circular or annular shape, and all components except the insulating member 25 are electrically connected to each other. The lower valve body 24 and the upper valve body 26 are connected at their respective central portions, and the insulating member 25 is located between their respective peripheral portions. If the internal pressure of the battery rises due to abnormal heating, the lower valve body 24 deforms and pushes the upper valve body 26 towards the cap 27, causing it to break. This cuts off the current path between the lower valve body 24 and the upper valve body 26. If the internal pressure rises further, the upper valve body 26 breaks, and gas is discharged from the opening of the cap 27.

[0027] Next, refer to Figures 2-4 To illustrate pad 28. Figures 2-4 All are cross-sectional views.

[0028] Figure 2 This indicates that the sealing body 17, which is equipped with a gasket 28, is supported by the groove portion 22 of the outer can 16, and the riveting portion 42 is formed (see reference). Figure 4 The gasket 28, when mounted on the sealing body 17, abuts against the sealing body 17 via the annular portion 30 and the protrusion 31 (described later). The gasket 28 can be mounted on the sealing body 17 before being placed on the groove portion 22, so that the sealing body 17 is positioned on the annular portion 30. Alternatively, the sealing body 17 can be inserted into the gasket 28 after the gasket 28 has been placed on the groove portion 22, thus mounting the gasket 28 onto the sealing body 17. In other words, in the method for manufacturing a cylindrical battery disclosed herein, the steps of mounting the gasket 28 on the sealing body 17 and the steps of placing the gasket 28 on the groove portion 22 can be interchanged.

[0029] like Figure 2 As shown, the gasket 28 includes: a cylindrical portion 29; and an annular portion 30 extending radially inward from one end of the cylindrical portion 29 in the axial direction. The cylindrical portion 29 has: an inner circumferential surface 34 extending axially on the inner circumferential side; and an outer circumferential surface 35 extending axially on the outer circumferential side. Furthermore, the cylindrical portion 29 includes: a protrusion 31 protruding radially inward between the two ends in the axial direction.

[0030] Reference Figure 2 The outer diameter of the cylindrical portion 29 is smaller than the inner diameter of the outer can 16, while the inner diameter is larger than the outer diameter of the sealing body 17. However, the size of the cylindrical portion 29 is not limited to this. The inner diameter of the cylindrical portion 29 may also be formed to be the same as or slightly smaller than the outer diameter of the sealing body 17. In this case, the gasket 28 expands the cylindrical portion 29 and fits it onto the sealing body 17. Alternatively, with the gasket 28 fitted onto the sealing body 17, the outer diameter of the cylindrical portion 29 may be formed to be the same as the inner diameter of the opening of the outer can 16, allowing it to be inserted into the groove portion 22 from the opening of the outer can 16.

[0031] The annular portion 30 extends radially inward toward the outer can 16 and is supported by the groove portion 22. The front end of the annular portion 30 extends radially inward further than the groove portion 22.

[0032] The protrusion 31 has a first inclined portion 32 located on the lower side (the side of the annular portion 30) and a second inclined portion 33 located on the upper side (the opposite side of the annular portion 30) on the inner peripheral surface 34. Furthermore, the protrusion 31 may have a flat portion 36 between the first inclined portion 32 and the second inclined portion 33 along the axial direction of the cylindrical portion 29.

[0033] The sealing body 17 has a top surface 39 and a side surface 41 on the flange portion, and an R-shaped corner portion 40 is located between the top surface 39 and the side surface 41 of the flange portion. The shape shown in the attached figure is merely illustrative. Furthermore, the corner portion 40 can be straight. The gasket 28 is configured to abut against the bottom of the sealing body 17 via an annular portion 30, and the protrusion 31 abuts against the corner portion 40.

[0034] When the gasket 28 is fitted onto the sealing body 17 so that the sealing body 17 is positioned on the annular portion 30, the first inclined portion 32 is formed to be located lower than the top surface 39 of the flange portion of the sealing body 17. When the riveting portion 42 is formed by the first inclined portion 32 being located lower than the top surface 39 of the flange portion of the sealing body 17, the protrusion 31 is less likely to climb onto the top surface 39 of the flange portion of the sealing body 17, making it difficult to form a gap between the gasket 28 and the sealing body 17.

[0035] In cross-sectional view, the length between the first inclined portion 32 and the annular portion 30 on the inner circumferential surface 34 of the gasket 28 is shorter than the length of the side surface 41 of the sealing body 17 (the length between the bottom surface of the sealing body 17 and the corner portion 40). Furthermore, the first inclined portion 32 is formed to be located lower than the top surface 39 of the flange portion of the sealing body 17. As a result, when the gasket 28 is fitted onto the sealing body 17, the first inclined portion 32 abuts against the corner portion 40 without extending beyond the top surface 39 of the flange portion. This prevents the sealing body 17 from falling off the gasket 28 before the riveting portion 42 is formed.

[0036] like Figure 3As shown, the flat portion 36 has only a length L along the axial direction of the cylindrical portion 29 between the first inclined portion 32 and the second inclined portion 33. By providing the flat portion 36, it also prevents the portion of the gasket 28 that abuts against the corner portion 40 from flowing to the top surface 39 side of the flange portion of the sealing body 17 when the riveting portion 42 is formed. In this disclosure, the flat portion 36 is not necessary.

[0037] In addition to the above, by increasing the angle θ1 (hereinafter referred to as the angle θ1 of the first inclined portion 32) formed by the portion of the inner peripheral surface 34 of the first inclined portion 32 and the cylindrical portion 29 adjacent to the first inclined portion 32, the gap between the gasket 28 and the outer can 16 when the riveting portion 42 is formed can be reduced. The reason for this is that the riveting portion 42 is formed by the first inclined portion 32 abutting against the corner 40 of the sealing body 17, which has the effect of preventing the portion of the gasket 28 abutting against the corner 40 from climbing onto the top surface 39 of the flange of the sealing body 17.

[0038] Considering the above-mentioned effects, the angle θ1 of the first inclined portion 32 is preferably formed to be 130° or more. The upper limit of the angle θ1 of the first inclined portion 32 is set from the viewpoint of preventing the sealing body 17 from falling off. If the angle θ1 of the first inclined portion 32 is 175° or less, when the gasket 28 is fitted onto the sealing body 17, the first inclined portion 32 abuts against the corner 40 of the sealing body 17, thereby preventing it from falling off. Therefore, by forming the angle θ1 of the first inclined portion in the range of 130° or more and 175° or less, the gap of the riveting portion 42 can be reduced compared to the case of conventional gaskets. Furthermore, it is more preferable to form the angle θ1 of the first inclined portion 32 in the range of 150° or more and 170° or less. In this way, the gap between the gasket 28 and the outer can 16 when the riveting portion 42 is formed can be suppressed to be smaller, and the prevention of the sealing body 17 from falling off the gasket 28 can be effectively achieved.

[0039] The second inclined portion 33 is formed above the first inclined portion 32 (or even above it if the flat portion 36 is provided). The angle θ2 between the second inclined portion 33 and the portion of the inner circumferential surface 34 of the cylindrical portion 29 adjacent to the second inclined portion 33 is, for example, 150°.

[0040] Furthermore, the first inclined portion 32 and the second inclined portion 33 do not need to be formed by flat surfaces; they can also be formed by curved surfaces. In this case, when viewed in cross-section, the angle θ1 of the first inclined portion 32 is defined as the angle greater than 90° between the straight line connecting the root end of the inner circumferential surface 34 of the first inclined portion 32 and the other end of the inner diameter side of the first inclined portion 32, and the inner circumferential surface 34. The angle θ2 of the second inclined portion 33 is defined similarly.

[0041] Next, use Figure 2 , Figure 4 This explains the mechanism by which the gasket 28 of this embodiment is unlikely to create a gap between the gasket 28 and the outer can 16 when the riveting part 42 is formed.

[0042] like Figure 2 As shown, in this embodiment, before the riveting portion 42 is formed, the first inclined portion 32 of the gasket 28 is located lower than the top surface 39 of the flange portion of the sealing body 17. Therefore, when the riveting portion 42 is formed, the protrusion 31 has difficulty climbing onto the top surface 39 of the flange portion of the sealing body 17 and is difficult to push radially inward towards the sealing body 17. Furthermore, if the flat portion 36 is formed, when the riveting portion 42 is formed, the first inclined portion 32 and the flat portion 36 abut along the corner 40 of the sealing body 17. Therefore, the protrusion 31 has difficulty being further pushed radially inward towards the sealing body 17. As a result, the amount of flow into the radially inward direction of the sealing body 17 in the portion of the gasket 28 other than the protrusion 31 is reduced. Therefore, in this embodiment, when the riveting portion 42 is formed, the gasket 28, as... Figure 4 As shown, this makes it difficult for gaps to form between the gasket 28 and the outer can 16.

[0043] Furthermore, in this embodiment, the portion of the gasket 28 that abuts against the corner 40 is difficult to flow towards the radially inner side of the sealing body 17. Therefore, when the protrusion 31 abuts against the corner 40 of the sealing body 17, it is only pushed up by the thickness of the protrusion 31 in the direction from the corner 40 toward the outer can 16. As a result, the generation of gaps is further suppressed.

[0044] As explained above, by using the gasket 28 of this embodiment, a cylindrical battery 10 with high sealing performance can be achieved, which is less likely to produce a gap between the outer can 16 and the gasket 28.

[0045] The method for manufacturing the cylindrical battery 10 utilizing the gasket 28 of this embodiment described above is as follows: First, the gasket 28 is fitted onto the sealing body 17, such that the sealing body 17 is disposed on the annular portion 30. At this time, the first inclined portion 32 is disposed at a position extending beyond the top surface 39 of the flange portion of the sealing body 17. Second, the sealing body 17, on which the gasket 28 is fitted, is disposed on the groove portion 22 formed by extending inward from the side near the opening of the bottomed cylindrical outer can 16. Third, the edge of the opening of the outer can 16 is bent inward to form a riveting portion 42, so that the gasket 28 and the outer can 16 are compressed by the sealing body 17. The cylindrical battery 10 is manufactured in this way.

[0046] According to the manufacturing method of the cylindrical battery utilizing the gasket of this embodiment, it is difficult to generate a gap between the outer can and the gasket at the riveting part. Therefore, it is possible to manufacture a cylindrical battery with high sealing performance.

[0047] The following detailed description is provided through embodiments, but this disclosure is not limited to these embodiments.

[0048] [Making the positive electrode plate]

[0049] LiNi is used as a positive electrode active material. 0.8 C o0.15 Al 0.05 O2. A positive electrode slurry is prepared by mixing 100 parts by weight of the positive electrode active material, 1.7 parts by weight of polyvinylidene fluoride as a binder, and 2.5 parts by weight of acetylene black as a conductive agent with a dispersant. This positive electrode slurry is coated onto both sides of a positive electrode current collector containing aluminum foil, except for the connecting portion of the positive electrode tab. After drying, the coating is compressed to a given thickness to obtain a positive electrode plate. The positive electrode plate is cut to a given size, and an Al-made positive electrode tab is ultrasonically welded to the exposed portion of the current collector.

[0050] [Making the negative electrode plate]

[0051] Graphite was used as the negative electrode active material. 100 parts by weight of the negative electrode active material, 0.6 parts by weight of polyvinylidene fluoride as a binder, carboxymethyl cellulose as a thickener, and an appropriate amount of water were stirred in a twin-arm mixer to prepare a negative electrode slurry. This negative electrode slurry was coated on both sides of a negative electrode current collector containing copper foil, except for the connection portions of the negative electrode tabs, and allowed to dry. The coating was then compressed to a given thickness, thereby obtaining a negative electrode plate. The negative electrode plate was cut to a given size, and negative electrode tabs containing a Ni-Cu-Ni cladding material were ultrasonically welded to the exposed portion of the current collector.

[0052] [Preparation of non-aqueous electrolytes]

[0053] A non-aqueous electrolyte was prepared by dissolving lithium hexafluorophosphate (LiPF6) as an electrolyte in a mixed solvent of ethylene carbonate (EC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC) to achieve a concentration of 1.0 mol / L.

[0054] [Preparation of the Pad in the Example]

[0055] To understand the impact of the clearance between the outer can and the gasket, gaskets with different parameters for the protrusions were prepared. Figure 3 The parameters are shown below. Examples 1 to 4 are prepared in which the angle θ1 of the first inclined section and the length L of the straight line of the flat section are changed respectively. The angle θ2 of the second inclined section is always set to 150°. The values ​​of the parameters for Examples 1 to 4 are shown below.

[0056] Example 1: θ1 = 150°, θ2 = 150°, L = 0.05mm

[0057] Example 2: θ1 = 150°, θ2 = 150°, L = 0.1mm

[0058] Example 3: θ1 = 170°, θ2 = 150°, L = 0.05mm

[0059] Example 4: θ1 = 170°, θ2 = 150°, L = 0.1mm

[0060] [Preparation of the padding for the comparative example]

[0061] As a comparative example, prepare Figure 5 The pad 43 is shown. In the comparative example pad 43, unlike the pad of the embodiment, when the sealing body 17 is disposed on the annular portion 30 of the pad 43, a protrusion 37 is formed such that a portion of the lower inclined portion of the protrusion 37 extends beyond the top surface 39 of the flange portion of the sealing body 17. Furthermore, in the protrusion 37, the upper and lower inclined portions are directly connected to form a vertex 38. Following the embodiment, the values ​​of the parameters when the angle between the lower inclined portion and the inner circumferential surface is set to θ1 and the angle between the upper inclined portion and the inner circumferential surface is set to θ2 are shown below.

[0062] Comparative examples: θ1 = 120°, θ2 = 150°

[0063] [Making a Cylindrical Battery]

[0064] An electrode body is fabricated by spirally winding the aforementioned positive and negative electrode plates together with a microporous membrane of polyolefin resin serving as a separator. This electrode body is then inserted into an outer can, manufactured by deep drawing a steel plate, through a circular insulating plate at the bottom. The negative electrode tab, connected to the negative electrode plate, and the bottom surface of the outer can are connected by welding. Next, after placing the insulating plate on the upper part of the electrode body, a U-shaped groove is formed on the side of the outer can, which is located above the insulating plate, by plastic forming in the circumferential direction. A predetermined amount of prepared non-aqueous electrolyte is then injected into the outer can containing the electrode body. The positive electrode tab, connected to the positive electrode plate, and the sealing body are then connected by welding. While folding the positive electrode tab, a gasketed sealing body is placed on the groove of the outer can. The edge of the opening of the outer can is bent inward to form a riveting joint, thereby compressing the gasket and the outer can through the sealing body to fabricate a cylindrical battery.

[0065] [Results of gap measurement and evaluation]

[0066] For Examples 1-4 and the Comparative Example, six cylindrical batteries were fabricated respectively, and the gap of the riveted joint was measured by observing the cross-section of the sealed body. Regarding the gap of the riveted joint in the Comparative Example, Figure 6The maximum gap was measured at the indicated position. Furthermore, the maximum gap was measured for Examples 1-4 in the same manner as for the Comparative Examples. Table 1 shows the average gap amounts of the riveted portions of the cylindrical batteries manufactured for Examples 1-4 and the Comparative Examples, respectively.

[0067] [Table 1]

[0068]

[0069] The gap amount of the riveted parts in Examples 1-4 is significantly smaller than that in the comparative examples. Therefore, it can be seen that the gaskets in the examples have the effect of reducing the gap amount of the riveted parts compared to the gaskets in the comparative examples. Furthermore, in the gaskets of the examples, it can be confirmed that increasing the angle θ1 of the first inclined portion reduces the gap amount. Furthermore, it can also be confirmed that increasing the length L of the straight line of the flat portion reduces the gap amount.

[0070] If the gap is reduced, the sealing performance improves. Therefore, by increasing the angle θ1 of the first inclined portion, the gap is reduced and the sealing performance improves. According to the evaluation results, by making the angle θ1 of the first inclined portion larger than that of the comparative example, the gap of the riveting portion can be reduced compared to the gasket of the existing example. For example, by forming the angle θ1 of the first inclined portion in the range of 130° to 175°, the gap of the riveting portion can be reduced, and the sealing performance can be improved. Furthermore, it is preferable to set the angle θ1 of the first inclined portion to be 150° to 170° or less.

[0071] In comparison with the comparative example, it can be seen that by providing a flat section, the gap is reduced and the airtightness is improved. Furthermore, by increasing the length L of the straight line in the flat section, the gap is reduced and the airtightness is improved.

[0072] Furthermore, the present invention is not limited to the above-described embodiments and their variations, and various changes and improvements can be made within the scope of the claims of this application.

[0073] -Symbol Explanation-

[0074] 10: Cylindrical battery; 11: Positive electrode; 12: Negative electrode; 13: Separator; 14: Electrode body; 16: Outer can; 17: Sealing body; 18, 19: Insulating plate; 20: Positive lead; 21: Negative lead; 22: Groove; 23: Internal terminal plate; 24: Lower valve body; 25: Insulating component; 26: Upper valve body; 27: Cap; 28, 43: Gasket; 29: Cylindrical part; 30: Circular part; 31: Protrusion; 32: First inclined part; 33: Second inclined part; 34: Inner circumferential surface; 35: Outer circumferential surface; 36: Flat part; 37: Protrusion; 38: Vertex; 39: Top surface; 40: Corner; 41: Side; 42: Riveting part; θ1: Angle of the first inclined part; θ2: Angle of the second inclined part.

Claims

1. A cylindrical battery gasket, compressed and fixed between a bottomed cylindrical outer can and a sealing body, said cylindrical battery gasket comprising: A cylindrical, tubular portion; and An annular portion extends radially inward from one end of the cylindrical portion along its axial direction. The cylindrical portion has a radially inwardly projecting protrusion between its two ends in the axial direction. The protrusion has: a first inclined portion located on the side of the annular portion; and a second inclined portion located on the end side of the cylindrical portion further axially than the first inclined portion. When the sealing body is disposed on the annular portion, the first inclined portion is formed at a position not exceeding the top surface of the flange portion of the sealing body.

2. The gasket for a cylindrical battery according to claim 1, wherein, When the sealing body is disposed on the annular portion, the first inclined portion is formed at a position that abuts against the corner portion between the top surface and the side surface of the flange portion.

3. The gasket for a cylindrical battery according to claim 1 or 2, wherein, The protrusion has a flat portion along the axial direction of the cylindrical portion between the first inclined portion and the second inclined portion.

4. The gasket for a cylindrical battery according to any one of claims 1 to 3, wherein, The angle between the portion of the first inclined portion and the inner circumferential surface of the cylindrical portion adjacent to the first inclined portion is 130° or more and 175° or less.

5. A method for manufacturing a cylindrical battery, wherein the cylindrical battery utilizes the gasket according to any one of claims 1 to 4, and the method for manufacturing the cylindrical battery comprises the following steps: The gasket is fitted onto the sealing body such that the sealing body is positioned on the annular portion; The gasket is disposed on the groove portion of the outer can, which extends inward from the side near the opening; and The edge of the opening of the outer can is bent inward to form a riveting part, so that the gasket and the outer can are compressed in the sealing body.

6. A cylindrical battery, comprising: The pad according to any one of claims 1 to 4; A cylindrical outer can with a bottom; and A sealing body disposed on the annular portion of the gasket, the sealing body being riveted and fixed to the outer can through the gasket.

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