Gasket for cylindrical battery and cylindrical battery comprising same

Abstract

A gasket (32) for an insulating cylindrical battery, in which a sealing body (24) for sealing an opening of a bottomed outer can (10) of the cylindrical battery is fitted, is provided with a bottom section and a cylindrical peripheral wall that rises upward from the peripheral section of the bottom section. An inclined surface (32A), which expands in diameter such that the outer diameter of the peripheral wall faces upward and becomes larger than the inner diameter of the open end (10A) of the outer can, is provided across the entire circumference of the outer peripheral portion of the gasket, and the peripheral wall is shaped such that the thickness of the wall gradually increases upward.

Description

Technical Field

[0001] The present disclosure relates to a gasket for a cylindrical battery and a cylindrical battery including the gasket. Background Art

[0002] In recent years, nickel-metal hydride batteries have been used in various fields as a representative cylindrical secondary battery. Nickel-metal hydride batteries generally have the following structure: a sealing body including a safety valve is arranged at the open end of a cylindrical outer can with a bottom through an insulating gasket, and then the outer can is riveted and the open end is sealed with the sealing body. In addition, in the manufacturing process of the battery, the process in which the sealing body is pre-fitted to the gasket and then arranged at the open end of the battery can together with the gasket has become the mainstream.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2010-40407 Summary of the invention

[0006] The cylindrical battery gasket disclosed in the present invention is an insulating cylindrical battery gasket that is embedded with a sealing body that seals the opening of a bottomed outer can of a cylindrical battery. The gasket includes: a bottom and a cylindrical peripheral wall that rises upward from the peripheral portion of the bottom, and an inclined surface that expands in diameter in a manner that increases the outer diameter of the peripheral wall toward the upper side compared to the inner diameter of the opening end of the outer can is provided throughout the entire circumference of the outer peripheral portion of the gasket, and the peripheral wall is configured to have a shape in which the thickness of the wall gradually increases toward the upper portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] [ Figure 1 ] Figure 1 It is a longitudinal sectional view showing a cylindrical battery according to one embodiment.

[0008] [ Figure 2 ] Figure 2 It is a schematic diagram showing a cylindrical battery gasket and an outer can of a cylindrical battery according to one embodiment.

[0009] [ Figure 3 ] Figure 3 This is a schematic diagram showing a state where a gasket is arranged at the open end of a battery can at the initial stage of the caulking process.

[0010] [ Figure 4 ] Figure 4 This is a schematic diagram showing the gasket and the outer can in a riveted state.

[0011] [ Figure 5A ] Figure 5A This is a schematic diagram for explaining an improved insulating ring.

[0012] [ Figure 5B ] Figure 5B This is a schematic diagram for explaining an improved insulating ring.

[0013] [ Figure 6 ] Figure 6 This is a schematic diagram for explaining a conventional gasket. DETAILED DESCRIPTION

[0014] In the following description, the gasket of the present embodiment and the battery using the gasket are described with reference to the accompanying drawings. In addition, the accompanying drawings are partially emphasized, enlarged, reduced, or omitted for the purpose of deepening understanding, and sometimes cannot accurately show the proportions or shapes of the various components. In addition, in order to facilitate understanding, the accompanying drawings are sometimes illustrated by changing the length of each component or the position of each component.

[0015] Figure 1 A nickel-hydrogen secondary battery 1 is shown as a cylindrical battery according to one embodiment of the present disclosure.

[0016] The battery 1 is, for example, a cylindrical battery of AA size with a height of 50.5 mm and an outer diameter of 14.5 mm, and includes an outer can 10 having a bottomed cylindrical shape with one end open. The outer can 10 is formed by a multi-stage press from a nickel-plated steel plate into a bottomed cylindrical shape with an open end 10A at one end and a closed bottom 10B at the other end. In addition, the outer surface of the bottom 10B, which is the bottom wall of the outer can 10, functions as a negative electrode terminal having conductivity.

[0017] The outer can 10 contains an electrode group 12 having a substantially cylindrical shape and an alkaline electrolyte (not shown). The electrode group 12 includes a positive electrode plate 16, a negative electrode plate 18, and a separator 20, each of which is in a strip shape. The separator 20 is sandwiched between the positive electrode plate 16 and the negative electrode plate 18. The positive electrode plate 16, the negative electrode plate 18, and the separator 20 are wound in a spiral shape. A portion of the negative electrode plate 18 is located at the outermost periphery of the electrode group 12. The negative electrode plate 18 is electrically connected to the outer can 10 by the outermost periphery of the negative electrode plate 18 being in contact with the inner peripheral surface 10C of the outer can 10.

[0018] The positive electrode plate 16 is a strip electrode filled with a positive electrode active material. On the other hand, the negative electrode plate 18 is a strip electrode containing a hydrogen absorbing alloy. In addition, the separator 20 contains, for example, a material formed by adding a hydrophilic group to a non-woven fabric of polyolefin-based fibers. As the alkaline electrolyte, for example, a potassium hydroxide aqueous solution, a lithium hydroxide aqueous solution, a sodium hydroxide aqueous solution, or a mixed solution thereof can be used.

[0019] One end of the collector connector 22 is electrically connected to the positive electrode plate 16 near the open end 10A of the outer can 10. The other end of the collector connector 22 is electrically connected to a conductive circular sealing plate 24. The sealing plate 24, which serves as a sealing body, has a vent 26 in the center. A rubber valve body 28 is arranged on the outer surface of the sealing plate 24 in a manner that blocks the vent 26. Furthermore, a positive terminal 30 with a cylindrical shape with a flange that covers the valve body 28 is fixed on the outer surface of the sealing plate 24. The positive terminal 30 presses the valve body 28 against the sealing plate 24. The length of the positive terminal 30 (for example, the length in the horizontal direction) is sometimes shorter than the length shown in the figure, and sometimes longer than the length shown in the figure. Therefore, the positive terminal 30 is sometimes clamped between the sealing plate 24 and the gasket 32, and sometimes not clamped between the sealing plate 24 and the gasket 32. In addition, the positive electrode terminal 30 may be disposed so as to be embedded in the sealing plate 24 or may be disposed so as to be mounted on the upper surface of the sealing plate 24 .

[0020] The exhaust hole 26 is normally sealed airtightly by the valve body 28. On the other hand, when gas is abnormally generated in the outer can 10 and the internal pressure thereof increases, the valve body 28 is compressed and the exhaust hole 26 communicates with the outside, so that the gas is discharged from the outer can 10. In this way, the sealing plate 24, the valve body 28 and the positive terminal 30 form a safety valve.

[0021] The sealing plate 24 is arranged on the side of the open end 10A of the outer can 10. A gasket 32 ​​containing an insulating material is clamped between the outer peripheral portion of the sealing plate 24 and the inner peripheral surface 10C of the outer can 10. The insulating material is, for example, a fluororesin such as polytetrafluoroethylene (PTFE), perfluoroalkyl compound (PFA), fluorinated ethylene propylene (FEP) or a nylon resin (polyamide). The sealing plate 24 and the gasket 32 ​​are fixed to the open end 10A of the outer can 10 by riveting the portion on the side of the open end 10A of the outer can 10 toward the sealing plate 24, thereby closing the open end 10A. Riveting is a method of deforming a part of a part and fixing one part to another part. The gasket 32 ​​prevents a short circuit between the sealing plate 24 connected to the positive terminal 30 and the outer can 10 that forms a negative terminal by electrical connection with the negative plate 18. In addition, the gasket 32 ​​prevents the electrolyte from leaking from the outer can 10 .

[0022] A sealing plate receiving portion 10D is formed on the inner circumferential surface 10C of the outer can 10, and the sealing plate receiving portion 10D protrudes from the inner circumferential surface 10C toward the central axis X of the battery to reduce the inner diameter and extends in the circumferential direction. The sealing plate receiving portion 10D is a portion of the sealing plate 24 inserted from the open end 10A of the outer can 10 and disposed in the outer can 10 via the gasket 32.

[0023] In addition, in the metal outer can 10, the peripheral portion of the periphery of the opening area 10E, the outer surface of the peripheral wall of the outer can, and the peripheral portion of the periphery of the bottom 10B are covered and insulated by an outer label 36 containing a heat shrinkable material. In addition, the opening area 10E is a circular area formed by the riveted opening end 10A and the positive terminal 30 protrudes to the outside. An annular (ring-shaped) and flat insulating ring 34 is arranged between the peripheral portion of the periphery of the opening area 10E and the outer label 36. The purpose of the insulating ring 34 is to prevent a short circuit of the battery 1, in particular, to prevent a short circuit between the positive terminal 30 and the outer can 10. The insulating ring 34 contains, for example, an insulating material such as cellulose fiber or polypropylene resin.

[0024] Let’s say, Figure 6 It can be seen that the conventional gasket includes a cylindrical portion having the same shape as the outer can 10. The outer peripheral surface 132A of the conventional gasket 132 extends vertically upward from the peripheral portion of the bottom 132B of the gasket 132 so as to be parallel to the inner peripheral surface 10C on the side of the opening end 10A of the outer can 10 when inserted. In addition, the outer peripheral surface of the sealing body 24 inserted into the outer can 10 together with the gasket 132 is formed into a cylindrical shape. Moreover, the inner peripheral surface 132C of the gasket 132 with the sealing body 24 also has a cylindrical surface. In this case, if the sealing plate 24 pre-fitted to the gasket 132 is inserted into the opening end 10A of the outer can 10 together with the gasket 132 and the opening end 10A is riveted, as described above, problems may occur when the gasket 132 is deformed due to the riveting. Specifically, when the upper portion of the peripheral wall of the gasket 132 is bent toward the central axis of the battery during the deformation, the sealing plate 24 floats and may deviate from the pre-fitted position of the gasket 132 or come off the gasket, which is a problem.

[0025] Figure 2 The gasket 32 ​​of the present embodiment shown in the figure solves the above problem. Figure 2It can be seen that in the gasket 32, the outer peripheral surface 32A as an inclined surface is provided throughout the entire circumference of the outer peripheral portion of the gasket 32, and the outer peripheral surface 32A as an inclined surface gradually expands in diameter in a manner that the outer diameter of the peripheral wall of the gasket is directed upward and becomes larger than the inner diameter of the opening end 10A of the outer can 10. In detail, when an imaginary outer peripheral surface corresponding to the outer peripheral surface of the existing gasket 132 is used as the reference plane 32Y, the outer peripheral surface 32A of the gasket 32 ​​of the present embodiment includes an inclination having an angle theta (θ) formed by a straight line along the outer peripheral surface 32A and a straight line along the reference plane 32Y. Moreover, the inclination included in the outer peripheral surface 32A is inclined in a manner that the outer peripheral portion of the gasket 32 ​​is expanded upward. That is, the inclination included in the outer peripheral surface 32A is inclined in a form in which the upper side is directed radially outward relative to the reference plane 32Y. That is, the outer peripheral surface 32A extends upward from the peripheral portion of the bottom 32B of the gasket 32 ​​while being inclined radially outward at an angle θ. In this case, the peripheral wall of the gasket 32 ​​is configured such that the thickness of the wall gradually increases to a width W at the upper end of the gasket toward the upper portion.

[0026] In the following description, the production of the battery 1 when the gasket 32 ​​of the present embodiment is used will be briefly described.

[0027] like Figure 1 As shown, the battery 1 is formed by inserting the electrode group 12 from the opening end 10A of the outer can 10 , welding one end of the current collector tab 22 to a predetermined position of the positive electrode plate 16 , and injecting an alkaline electrolyte into the outer can 10 .

[0028] like Figure 2 As shown in FIG. 1 , the gasket 32 ​​is configured in a state where the sealing plate 24 is fitted in advance into the space defined by the inner peripheral surface 32C thereof so as to contact the sealing portion 32D of the gasket 32. Figure 3 As shown, the gasket 32 ​​is pressed into the outer can 10 from the open end 10A of the outer can 10 toward the bottom 10B. As the gasket 32 ​​is pressed into the outer can 10, it expands toward its upper part, and the outer peripheral surface 32A of the outer peripheral portion inclined toward the radial outer side becomes parallel to the inner peripheral surface 10C of the open end 10A, and contacts the inner peripheral surface 10C. At this time, the gasket 32 ​​is deformed in such a way that the thick-walled portion of its upper part is bent toward the central axis X of the battery and radially inward. Through the deformation, the sealing plate 24 is in a state of being tightly fixed to the inner peripheral surface 32C in such a way that its outer peripheral portion is wrapped by the inner peripheral surface 32C of the gasket 32.

[0029] Thereafter, the sealing plate 24 is further pressed toward the bottom 10B side together with the gasket 32 ​​in the fixed state, so as to be arranged on the upper side of the necked portion forming the sealing plate receiving portion 10D. At this time, the other end of the current collector joint 22 is connected to the sealing plate 24. It is sufficient that at least a portion of the current collector joint 22 is connected to the sealing plate 24. Therefore, the current collector joint 22 can be arranged on the lower surface of the sealing plate 24 across the exhaust hole 26, or it can be arranged on the lower surface of the sealing plate 24 without crossing the exhaust hole 26.

[0030] Next, in order to fix the sealing plate 24 by riveting, the edge of the opening end 10A of the outer can 10 is bent toward the central axis X of the battery together with the thick-walled opening end of the gasket 32 ​​by a jig. At this time, the sealing plate 24 is already closely fixed to the inner peripheral surface 32C of the gasket 32 ​​in such a manner that the inner peripheral surface 32C of the gasket 32 ​​wraps the outer peripheral portion thereof when the sealing plate 24 is arranged at the opening end of the battery can together with the gasket 32 ​​as described above. Therefore, when the outer can 10 is riveted, the sealing plate 24 is prevented from deviating from the pre-fitted position or coming off the gasket 32 ​​by the action of the gasket 32.

[0031] As described above, in this embodiment, when the outer can 10 is riveted, the sealing plate 24 can be prevented from being displaced or separated from the gasket 32, that is, the movement of the sealing plate 24 relative to the gasket 32, so that the contact between the sealing plate 24 and the outer can 10, that is, the short circuit of the electrodes can be prevented. In addition, in this case, the sealing plate 24 is fixed to a predetermined position relative to the outer can 10, so the appearance of the battery 1 can also be prevented from being defective.

[0032] Thereafter, the sealing plate receiving portion 10D is formed by a portion of the outer can 10 that is previously necked down so as to reduce the inner diameter. In order to caulk the outer can 10 sufficiently, a pressure in the direction of the central axis X is applied to the outer can 10 .

[0033] Figure 4 The exterior can 10 is shown after the exterior can 10 is caulked and the open end 10A is sealed with the sealing plate 24 .

[0034] After the caulking step is performed as described above, the thick-walled portion of the gasket 32 ​​crushed by the caulking extends from between the opening end 10A of the outer can 10 and the sealing plate 24 toward the positive terminal 30 , and the extended portion protrudes upward to form a protrusion 32E.

[0035] As described above, in the present embodiment, after the outer can 10 is riveted, the portion of the outer peripheral portion of the gasket 32 ​​that is crushed by riveting and formed thicker than the conventional gasket seals the inner peripheral surface 10C of the opening end 10A of the outer can 10 and the sealing plate 24. In this case, a gap is less likely to be generated around the gasket 32, especially between the gasket 32 ​​and the inner peripheral surface 10C of the opening end 10A, and the airtightness between the upper portion of the gasket 32 ​​and the outer can end is improved, so that the leakage of the electrolyte can be suppressed in the present embodiment.

[0036] In addition, the protrusion 32E of the gasket 32 ​​formed by riveting is also effective in suppressing the contact between the sealing plate 24 and the outer can 10, that is, the short circuit of the electrode. In addition, in terms of the installation of the insulating ring 34 on the outer can 10, the protrusion 32E needs to make the height "H" of the upper end surface of the outer can 10 after riveting as a reference to be "less than 1 mm", and it is particularly preferably in the range of "0.01mm to 1.00mm". The reason is that if the height "H" of the protrusion 32E exceeds "1mm", the insulating ring 34 may be poorly inserted into the outer can 10 due to the presence of the protrusion 32E. In addition, depending on the shape of the outer can or the shape of the insulating ring, the height H may also be "more than 1.01mm".

[0037] Next, in order to prevent the electrodes from short-circuiting, an insulating ring 34 is installed on the outer can 10. In detail, in the outer can 10, a circular opening area 10E is formed by the riveted open end 10A, where the positive terminal 30 protrudes to the outside. Then, a circular and flat insulating ring 34 is arranged in the peripheral portion of the periphery of the opening area 10E in a manner that covers the opening area. Moreover, the insulating ring 34 arranged as described above is fixed to the upper surface of the peripheral portion of the periphery in the opening area 10E. Thus, the insulating ring 34 is installed. In addition, at this time, the protrusion 32E of the gasket 32 ​​protrudes upward from the peripheral portion of the opening area 10E. Through the installation, the protrusion 32E abuts against the lower surface of the insulating ring 34.

[0038] Thereafter, for insulation in particular, the peripheral portion of the peripheral edge of the opening region 10E in the outer can 10, the outer surface of the peripheral wall, and the peripheral portion of the peripheral edge of the bottom 10B are covered with the outer label 36. At this time, the peripheral portion of the peripheral edge of the opening region 10E is covered by sandwiching the insulating ring 34 between the peripheral portion of the peripheral edge and the outer label 36.

[0039] In the following description, in order to observe the difference in manufacturing defects, as an example when using the gasket of the embodiment and the existing gasket, 10,000 AA-size cylindrical batteries were manufactured and the differences were compared. Regarding the gasket, the gasket of the embodiment and the existing gasket were verified using a gasket made by adding 0.2% carbon black to the nylon resin. The items of manufacturing defects in which differences were observed were set as "riveting short circuit failure" caused by gasket detachment, "gasket deviation (no short circuit)" based on visual inspection, and "electrolyte leakage". The batteries in the exposed state (not covered by the outer label 36) after riveting the outer can 10 were used for investigation. Regarding electrolyte leakage, a high-temperature cycle test for leakage verification was implemented before the service life was reached, and the number of leakages caused by the airtightness of the gasket was investigated.

[0040] In addition, in order to observe the difference when the angle θ of the inclination of the outer peripheral surface of the gasket of the above embodiment is different, cylindrical batteries are manufactured and compared using three gaskets with different angles θ. The angle θ is set to "5 degrees" in the first embodiment 1, "15 degrees" in the second embodiment 2, and "25 degrees" in the third embodiment 3.

[0041] In addition, in order to observe the occurrence of poor insertion of the insulating ring caused by the height H of the protruding portion of the gasket of the embodiment, a cylindrical battery was also manufactured as a comparative example for a gasket with an angle θ of "30 degrees" and compared. Here, as shown in Table 1, for example, in the case of a gasket with an angle θ of "30 degrees", the width W of the upper end of the gasket is "1.60 mm", and a protruding portion with a height of "1.20 mm" is formed in the gasket after riveting to the outer can. In addition, for example, in the case of angles θ of "5 degrees", "15 degrees", and "25 degrees", the width W of the upper end of the gasket is "0.62 mm", "0.98 mm", and "1.38 mm", respectively. Moreover, in the gasket after riveting to the outer can, protruding portions with heights of "0.01 mm", "0.50 mm", and "1.00 mm" are formed.

[0042] In addition, the conventional gasket has no inclination at the outer periphery, so the angle θ is "0 degrees", the width W of the upper end of the gasket is "0.45 mm", and in this case, since no protrusion is formed, its height H is "0.00 mm". The comparative example is not a prior art, and the comparative example can also be applied to a nickel-hydrogen secondary battery or a gasket.

[0043] [Table 1]

[0044]

[0045] As can be seen from Table 1, when the existing gaskets were used, manufacturing defects of the batteries occurred, such as "1" out of 10,000 batteries had a poor riveting short circuit, "20" had gasket displacement, and "10" had electrolyte leakage. On the other hand, when the gaskets of Examples 1 to 3 were used, manufacturing defects such as poor riveting short circuits, gasket displacement, and electrolyte leakage did not occur at all in the manufacture of 10,000 batteries. As described above, by providing an inclination on the outer periphery of the gasket so that the outer diameter of the gasket becomes larger toward the upper part than the inner diameter of the outer can and the thickness of the peripheral wall gradually becomes thicker toward the upper part, it is possible to manufacture higher quality batteries.

[0046] In addition, when the comparative example shown in Table 1, i.e., the gasket having an angle θ of "30 degrees" and a height H of "1.20 mm", was used, "12" of the 10,000 batteries had poor insertion of the insulating ring. On the other hand, when using Examples 1 to 3, i.e., the gasket having an angle θ of "5 degrees to 25 degrees" and a height H of "0.01 mm to 1.00 mm", no poor insertion of the insulating ring occurred in the manufacture of 10,000 batteries. Based on the results, it can be considered that when using the gasket of the embodiment, in order to avoid poor insertion of the insulating ring into the outer can, the height H of the protrusion can be set to the range of "0.01 mm to 1.00 mm".

[0047] Furthermore, as is apparent from Table 1, even when the gasket of the comparative example was used, manufacturing defects such as caulking short-circuit failure, gasket displacement, and electrolyte leakage did not occur at all in the production of 10,000 batteries.

[0048] Furthermore, from the viewpoint of suppressing the leakage of the electrolyte, the thickness of the peripheral wall of the upper part of the gasket is preferably increased (thickened) within a certain range. If so, the deformation of the gasket caused by the riveting of the outer can can improve the airtightness around the gasket, especially between the gasket and the inner peripheral surface of the outer can, so that the leakage of the electrolyte can be suppressed. However, if the thickness of the peripheral wall of the upper part of the gasket is increased, the height H of the protrusion becomes higher as described above, resulting in poor insertion of the insulating ring.

[0049] Therefore, the inventors have improved the insulating ring in order to increase the thickness of the peripheral wall of the upper portion of the gasket and suppress the occurrence of poor insertion of the insulating ring. Figure 5A and Figure 5B An insulating ring 34' with a modification is shown. The insulating ring 34' with a modification may or may not be applicable to the embodiment.

[0050] like Figure 5AAs shown, for the insulating ring 34', compared with the existing annular (ring-shaped) and flat insulating ring, a mountain-folded convex portion 34'B that is raised like a mountain is provided on the upper surface side of the flat annular portion 34'A. The mountain-folded convex portion 34'B is formed so that when the height (thickness) of the annular portion 34'A of the insulating ring 34' is H1, the height from the upper surface of the annular portion 34'A to the top of the convex portion 34'B is H2. In addition, Figure 5A The figure on the upper side is a schematic diagram of the insulating ring 34' observed from its upper surface side. Figure 5A The lower figure is a longitudinal sectional view of the insulating ring 34' when viewed from the side surface thereof.

[0051] The mountain-folded protrusion 34'B extends all around the annular portion 34'A of the insulating ring 34'. In addition, a concave portion that is formed into a valley-folded space facing upward is provided on the lower surface side of the annular portion 34'A of the insulating ring 34', at a portion corresponding to the back side of the protrusion 34'B. The improved insulating ring 34' is configured to receive the protrusion 32E of the gasket 32 ​​through the concave portion. Figure 5B As shown, the mountain-folded protrusion 34'B is provided at a position that can ensure positional consistency with the protrusion 32E in the radial direction of the annular portion 34'A of the insulating ring so as to receive the protrusion 32E of the gasket 32 ​​in the recessed portion on the lower surface side thereof.

[0052] In the following description, in order to observe the difference in the occurrence of poor insertion of the insulating ring when using the improved insulating ring and the existing insulating ring, 10,000 AA-size cylindrical batteries were manufactured as examples and the differences were compared. In addition, insulating rings containing cellulose fibers were used here. In addition, for the improved insulating ring, insulating rings with a height H1 and a height H2 of "0.25 mm" and "0.50 mm" were used, respectively.

[0053] As for the embodiments, three cases in which the height H of the protrusion is changed by making the thickness of the peripheral wall of the upper part of the gasket different are compared. Specifically, as described above, in the first embodiment, a comparative example in which insertion failure occurs when using a conventional insulating ring, that is, an example in which a gasket with an angle θ of "30 degrees" is used. Furthermore, examples in which a gasket with an angle θ of "40 degrees" and a gasket with an angle θ of "45 degrees" are newly added as embodiments 4 and 5, and these three embodiments, "comparative example", "embodiment 4", and "embodiment 5", are compared.

[0054] Here, as shown again in Table 2, in the case of the comparative example using a gasket with an angle θ of "30 degrees", the width W of the upper end of the gasket is "1.60 mm", and a protrusion with a height of "1.20 mm" is formed in the gasket after riveting to the outer can. In addition, in the case of Example 4 using a gasket with an angle θ of "40 degrees" and Example 5 using a gasket with an angle θ of "45 degrees" as new examples, the width W of the upper end of the gasket is "2.05 mm" and "2.50 mm", respectively. Moreover, in the gasket after riveting to the outer can, protrusions with heights of "1.80 mm" and "2.00 mm" are formed, respectively.

[0055] [Table 2]

[0056]

[0057] As can be seen from Table 2, in the case of the comparative example, when the existing insulating ring was used as described above, "12" batteries out of 10,000 batteries had poor insertion of the insulating ring. On the other hand, in the case of the comparative example, when the newly improved insulating ring was used, poor insertion of the insulating ring did not occur at all in the manufacture of 10,000 batteries. In addition, in the novel examples 4 and 5, when the existing insulating ring was used, poor insertion of the insulating ring occurred in "30" and "34" batteries out of 10,000 batteries, respectively. On the other hand, in the example of Example 4, when the improved insulating ring was used, poor insertion of the insulating ring did not occur at all in the manufacture of 10,000 batteries. However, in the example of Example 5, when the improved insulating ring was used, poor insertion of the insulating ring occurred in "10" batteries out of 10,000 batteries.

[0058] Based on these results, it can be considered that when using the improved insulating ring, if the height H of the protruding portion of the gasket is in the range of "0.01mm to 1.80mm", the occurrence of poor insertion of the insulating ring into the outer can can be suppressed. In this case, since the angle θ is expanded in the range of "5 degrees to 40 degrees", the width W of the upper end of the gasket is expanded in the range of "0.62mm to 2.05mm", so the thickness of the peripheral wall of the upper part of the gasket can be increased compared with the case of using the existing insulating ring. In addition, depending on the shape of the outer can or the shape of the insulating ring, the height H can be "1.81mm or more", the angle θ can be "1 degree to 4 degrees, 41 degrees or more", and the width W of the upper end of the gasket can be "0.01mm to 0.61mm, 2.06mm or more".

[0059] By using the improved insulating ring as described above, the thickness of the peripheral wall of the upper part of the gasket can be increased while suppressing the occurrence of poor insertion of the insulating ring. Therefore, if the improved insulating ring is used together with the gasket of the embodiment, the thickness of the peripheral wall of the upper part of the gasket can be increased, so that the occurrence of electrolyte leakage can be suppressed compared with the case of using the existing insulating ring.

[0060] Furthermore, as is apparent from Table 2, even when the gaskets of Examples 4 and 5 were used, manufacturing defects such as caulking short circuit failure, gasket displacement, and electrolyte leakage did not occur at all in the manufacture of 10,000 batteries.

[0061] [Illustrative Problems of the Present Disclosure]

[0062] The outer peripheral surface of the sealing body is formed into a cylindrical shape, and the inner peripheral surface of the gasket with which the sealing body is fitted also has a cylindrical surface. In addition, the gasket is formed into a cylindrical shape in terms of ease of insertion into the outer can. In the above structure, when the gasket is deformed by riveting the outer can in the riveting process, the sealing body floats up, sometimes deviating from the pre-fitted position of the gasket or detaching from the gasket. As a result, in the completed battery, a short circuit or poor appearance may occur, or leakage of electrolyte may occur from the gap around the gasket, especially between the gasket and the inner peripheral surface of the outer can.

[0063] In view of the above problems, an exemplary object of the present disclosure is to provide a cylindrical battery gasket capable of suppressing movement of a sealing body relative to the gasket when an exterior can is caulked. And a cylindrical battery including the gasket.

[0064] [Illustrative contents of the present disclosure]

[0065] The first disclosure is a gasket, which is an insulating cylindrical battery gasket embedded with a sealing body for sealing the opening of a bottomed outer can of the cylindrical battery, wherein the gasket includes: a bottom and a cylindrical peripheral wall rising upward from the peripheral portion of the bottom, and an inclined surface that expands in diameter in a manner that the outer diameter of the peripheral wall becomes larger toward the upper side than the inner diameter of the opening end of the outer can is provided throughout the entire circumference of the outer peripheral portion of the gasket, and the peripheral wall is configured to have a shape in which the thickness of the wall gradually increases toward the upper portion.

[0066] The second disclosure is a cylindrical battery, comprising: an outer can having a cylindrical shape and including an open end portion as an opening at one end in the axial direction of the outer can and a closed bottom portion as the other end in the axial direction, and capable of accommodating an electrode group and an electrolyte solution inside; a circular sealing body for sealing the open end portion of the outer can; and the gasket described in the first disclosure, which is arranged between the inner peripheral surface of the outer can and the sealing body at the open end portion of the outer can, the gasket being inserted into the open end portion of the outer can in a state where the sealing body is fitted, and in the outer can after the open end portion is riveted, a part of the gasket forms a protrusion protruding upward from the peripheral portion of the circular opening area formed by the riveted opening end portion, and at the peripheral portion of the peripheral edge of the opening area, an annular and flat insulating ring is arranged in a manner covering the opening area and is fixed to the upper surface of the peripheral portion.

[0067] The third disclosure is the cylindrical battery according to the second disclosure, wherein the protrusion of the gasket protrudes at a height within a range of 0.01 mm to 1.00 mm from a reference surface of the upper end portion of the outer can after the caulking.

[0068] The fourth disclosure is a cylindrical battery according to the second disclosure, wherein, in the insulating ring, a mountain-fold-shaped convex portion extending over the entire circumference of the annular portion is provided on the upper surface side of its flat annular portion, and a valley-fold-shaped concave portion is provided on the lower surface side of the annular portion at a portion corresponding to the back side of the convex portion, and the insulating ring is configured to receive the protrusion of the gasket by the concave portion when it is configured in a manner covering the opening area, and the protrusion of the gasket protrudes in a manner that takes the surface of the upper end portion of the riveted outer can as a reference and the height from the reference plane becomes higher than when the convex portion and the concave portion are not provided on the annular portion of the insulating ring.

[0069] [Exemplary Effects of the Present Disclosure]

[0070] According to the cylindrical battery gasket and the cylindrical battery including the gasket disclosed herein, it is possible to suppress the movement of the sealing body relative to the gasket when the outer can is caulked.

[0071] Explanation of symbols

[0072] 1: Battery

[0073] 10: External can

[0074] 10A: Open end

[0075] 10B: Bottom

[0076] 10C: Inner surface

[0077] 24: Sealing plate (sealing body)

[0078] 32: Washer

[0079] 32A: Outer surface (inclined surface)

[0080] 32B: bottom

[0081] 32C: Inner Surface

[0082] 32D: Sealing part

[0083] 32E: Protrusion

[0084] 32Y: Reference surface (imaginary outer surface)

[0085] 34: Insulation ring (existing)

[0086] 34': Insulating ring (an improved component)

[0087] 34'A: Ring

[0088] 34'B: Mountain fold-shaped convex part

[0089] H: Height of the protrusion

[0090] θ: Angle (angle of inclination, tilt)

[0091] W: Width of the upper end of the washer

[0092] X: The center axis of the battery

Claims

1. A gasket for an insulating cylindrical battery having a sealing member fitted therein for sealing an opening of a bottomed outer can of a cylindrical battery, wherein: The gasket includes a bottom and a cylindrical peripheral wall rising upward from the peripheral portion of the bottom, and an inclined surface that expands in diameter in a manner that the outer diameter of the peripheral wall becomes larger than the inner diameter of the opening end of the outer can toward the upper side is provided over the entire circumference of the outer peripheral portion of the gasket. The peripheral wall is configured such that the thickness of the wall gradually increases toward the upper portion.

2. A cylindrical battery comprising: The outer can has a cylindrical shape and includes an open end portion which is an opening at one end in the axial direction of the outer can and a closed bottom portion which is the other end in the axial direction, and can accommodate the electrode group and the electrolyte solution inside; A circular sealing body for sealing the open end of the outer can; as well as The gasket according to claim 1 is arranged between the inner peripheral surface of the outer can and the sealing body at the opening end of the outer can, The gasket is inserted into the open end of the outer can in a state where the sealing body is fitted therein, and in the outer can after the open end is riveted, a portion of the gasket forms a protrusion protruding upward from the peripheral edge of the circular opening area formed by the riveted open end. In the peripheral portion of the periphery of the opening region, an annular and flat insulating ring is arranged so as to cover the opening region and is fixed to the upper surface of the peripheral portion.

3. The cylindrical battery according to claim 2, wherein: The protrusion of the gasket protrudes in a range of 0.01 mm to 1.00 mm from a surface of the upper end portion of the outer can after the caulking as a reference plane.

4. The cylindrical battery according to claim 2, wherein: The insulating ring has a convex portion extending over the entire circumference of the annular portion on the upper surface side of the flat annular portion, and a concave portion formed in a valley shape and directed upward is provided on the lower surface side of the annular portion at a portion corresponding to the back side of the convex portion. The insulating ring is configured to receive the protruding portion of the gasket by the recessed portion when the insulating ring is arranged to cover the opening region. The protrusion of the gasket protrudes so that the height from the reference plane is higher than when the protrusion and the recess are not provided on the annular portion of the insulating ring, with the surface of the upper end portion of the caulking outer can being used as a reference plane.

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