Seal washer and cylindrical battery

Abstract

A seal gasket for a cylindrical battery provided with: a metal battery can having a bottomed cylindrical shape and having an open end having an inward diameter reduction; a power generation element housed in the battery can; a disc-shaped sealing plate made of metal and fitted to the opening end, the diameter of which decreases inward; and a resin seal washer sandwiched between the open end and the seal plate, the seal washer being provided with: a disk-shaped partition wall part; an outer peripheral part which is vertically arranged on the peripheral edge of the partition wall part and is clamped between the opening end and the sealing plate; and a plurality of stress buffer portions including a circular ring-shaped groove formed in the partition wall portion so as to be concentric with each other. The ratio (Ha / H) of the total height (H) from the lowermost position to the uppermost position of the seal washer to the thickness (Ha) of a region on the partition wall portion where the plurality of stress buffer portions are formed is 15% to 30%.

Description

[0001] This application is a divisional application of the Chinese invention patent application with the application date of December 25, 2019, application number 201980088968.5, and name “Purification Control Valve Device”. Technical Field

[0002] The invention relates to a sealing gasket and a cylindrical battery. Background Art

[0003] An example of a cylindrical battery equipped with a sealing gasket is a common LR6 alkaline battery. Figure 1 The internal structure of the alkaline battery 1 is shown. Figure 1 FIG. 1 shows a longitudinal cross section of the alkaline battery 1 when the extension direction of the cylindrical axis 100 is the vertical (longitudinal) direction. Figure 1 As shown, the alkaline battery 1 is composed of a bottomed cylindrical metal battery can 2, a positive electrode mixture 3 formed in a ring shape, a bottomed cylindrical separator 4 arranged inside the positive electrode mixture 3, a negative electrode gel 5 containing a zinc alloy and filled inside the separator 4, a negative electrode collector ring 6 formed of a rod-shaped metal inserted into the negative electrode gel 5, a disc-shaped metal negative terminal plate 7, a sealing gasket 120 made of resin, etc.

[0004] In this structure, the positive electrode mixture 3, the separator 4 and the negative electrode gel 5 form the power generation element of the alkaline battery 1 in the presence of an electrolyte. In addition, for the convenience of description, the bottom side of the battery can 2 is defined as the bottom to define the up and down directions. In addition, the direction perpendicular to the up and down directions and outward is defined as the radial direction. These two directions represent the relationship of relative directions determined for convenience.

[0005] The battery can 2 functions as a battery case and a positive electrode current collector by being in direct contact with the positive electrode mixture 3. A positive electrode terminal 8 is formed on the bottom surface of the battery can 2. The disc-shaped negative electrode terminal plate 7 is a disc-shaped plate with a flange-shaped edge, and when the positive electrode terminal 8 is at the bottom, the disc is inverted and embedded in the open end of the battery can 2 via a sealing gasket 120.

[0006] The upper end of the rod-shaped negative electrode collector ring 6 inserted into the negative electrode gel 5 is welded to the lower surface of the disc-shaped negative terminal plate 7. In addition, the negative terminal plate 7 is a sealing plate for closing the opening of the battery can 2, and the negative terminal plate 7, the negative electrode collector ring 6 and the sealing gasket 120 are pre-assembled into one body as a sealing body. Moreover, the sealing gasket 120 is riveted by inserting the sealing body into the battery can 2 and performing inward diameter reduction processing on the opening end of the battery can 2. That is, the sealing gasket 120 is clamped between the inner surface of the battery can 2 and the edge of the negative terminal plate 7, and the battery can 2 is sealed in a closed state.

[0007] Figure 21 is a diagram showing the structure of the sealing gasket 120, and the vertical direction of the sealing gasket 120 is defined in the state of being arranged in the battery can 2. Figure 2 , the shape of the sealing gasket 120 before being riveted to the open end of the battery can 2 is shown in a longitudinal cross-sectional view. The sealing gasket 120 is a cup-shaped having a wall surface (hereinafter, sometimes referred to as the outer peripheral portion 24) erected upward around the disc, and the center of the disc is a cylindrical boss portion 21 having a hollow portion (hereinafter, sometimes referred to as the boss hole 22) into which the negative electrode collector ring 6 is pressed. Moreover, when the sealing gasket 120 is assembled into the battery can 2, the storage space of the power generation element in the battery can 2 is sealed by the membrane-like portion (hereinafter, sometimes referred to as the partition wall portion 23) from the outer periphery of the boss portion 21 to the periphery of the disc, and the interior of the battery can 2 is divided into upper and lower parts.

[0008] In addition, as a sealing sequence of the battery can 2, first, the negative terminal plate 7, the negative collector ring 6 and the sealing gasket 120 are preliminarily combined as a sealing body. Next, the sealing gasket 120 is arranged in the battery can 2 with the curling portion 9 formed on the upper end side of the battery can 2 as a seat, and the opening of the battery can 2 is covered with the sealing gasket 120, the negative terminal plate 7 and the negative collector ring 6. Then, the opening end of the battery can 2 is reduced in diameter, and the battery can 2 is sealed.

[0009] A groove is formed on the partition wall 23 of the sealing gasket 120, which is concentric with the outer peripheral portion 24. For example, a groove-shaped thin-walled portion 25 is formed on a part of the inner surface of the partition wall 23. When the pressure in the battery can 2 increases abnormally, the thin-walled portion 25 breaks first, and finally the gas in the battery can 2 that causes the internal pressure is discharged through the exhaust hole 10 provided on the negative terminal plate 7 (see FIG. Figure 1 ) is discharged into the atmosphere, that is, it functions as an explosion-proof safety mechanism.

[0010] In addition, a stress buffering portion 130 is provided on the partition wall portion 23 of the sealing gasket 120. The stress buffering portion 130 absorbs the radially inward stress applied to the sealing gasket 120 when the opening end of the battery can 2 is subjected to the diameter reduction process when the battery can 2 is sealed. The stress buffering portion 130 has a longitudinal cross-sectional shape formed by bending a part of the partition wall portion 23. When stress is applied to the partition wall portion 23 in the radially inward direction, the disk shape of the partition wall portion 23 is uniformly deformed, thereby playing a function of suppressing unintentional breakage of the thin-walled portion 25 caused by uneven stress.

[0011] The stress buffering function of the stress buffering portion 130 is provided by the longitudinal cross-sectional shape of the partition wall portion 23 of the sealing gasket 120. Figure 2In the sealing gasket 120 shown, a stress buffering portion 130 that is bent downward and has a U-shaped longitudinal section is formed on the partition wall portion 23 on the way from the outer peripheral portion 24 to the boss portion 21. When the opening end of the battery can 2 is reduced in diameter and the sealing gasket 120 is riveted, the stress buffering portion 130 is bent in a manner that closes the opening of the U-shaped longitudinal section, thereby absorbing the stress on the partition wall portion 23 in the direction of the reduction in diameter.

[0012] Figure 3 Is with Figure 2 A longitudinal cross-sectional view of a sealing gasket 220 having a stress buffering portion 230 of different shapes. Figure 3 In the sealing gasket 220 shown, the portion of the partition wall 23 that extends obliquely upward from the inner periphery toward the outer periphery and then bends obliquely downward to reach the outer periphery 24 is a stress buffer 230. When the battery can 2 is sealed, the angles (θ1, θ2) of the bending portions at the upper surface side and the lower surface side of the partition wall 23 are variable, thereby absorbing the stress applied to the partition wall 23. In addition, the structure of the sealing gasket 220 having the above-mentioned stress buffer 230 is described in detail in the following patent document 1. In addition, the following non-patent document 1 describes a method for manufacturing an alkaline battery 1.

[0013] Prior art literature

[0014] Patent Literature

[0015] Patent Document 1: Japanese Patent Application Publication No. 2013-69459

[0016] Non-patent literature

[0017] Non-patent document 1: FDK Corporation, "How to manufacture alkaline batteries", [online], [retrieved on December 26, 2011], Internet<URL:http: / / www.fdk.co.jp / denchi_club / denchi_st ory / arukari.htm> Summary of the invention

[0018] Problems to be solved by the invention

[0019] Figure 2 and Figure 3 The shape of the stress buffer portion (130, 230) of the sealing gasket (120, 220) shown is optimized. When the open end of the battery can 2 is riveted and the battery can 2 is sealed by the sealing plate, the stress buffer portion (130, 230) is deformed, thereby reliably preventing the sealing gasket (120, 220) from being deformed and the thin-walled portion 25 from being broken.

[0020] However, since the stress buffering portion (130, 230) is easily flexed when the battery can 2 is sealed, it is bent on the partition 23 to protrude greatly downward. Therefore, when the sealing gasket (120, 220) as described above is used, it is difficult to increase the volume of the power generation element accommodating area from the lower surface of the partition 23 of the sealing gasket (120, 220) to the lower surface of the power generation element accommodating area in the battery can 2, which accommodates the power generation element (positive electrode mixture 3, separator 4, negative electrode gel 5, electrolyte). That is, when the sealing gasket (120, 220) as described above is used, the filling amount of the power generation element in the battery can 2 is limited, and it is difficult to improve the discharge performance.

[0021] Therefore, an object of the present invention is to provide a sealing gasket that can reliably absorb stress generated when the opening of a battery can of a cylindrical battery is sealed by reducing the diameter thereof and can increase the amount of power generation elements filled in the battery can, and a cylindrical battery having the sealing gasket.

[0022] Means of solving problems

[0023] One embodiment of the present invention for achieving the above-mentioned purpose is a sealing gasket for a cylindrical battery, wherein the cylindrical battery comprises: a metal battery can, which is a bottomed cylindrical shape and has an open end with a diameter that is reduced inwardly; a power generation element, which is accommodated in the battery can; a metal, disc-shaped sealing plate, which is embedded in the open end with a diameter that is reduced inwardly; and a resin sealing gasket, which is clamped by the open end and the sealing plate, wherein the sealing gasket comprises: a circular plate-shaped partition portion; an outer peripheral portion, which is upright on the periphery of the partition portion and is clamped between the open end and the sealing plate; and a plurality of stress buffering portions, wherein the plurality of stress buffering portions include annular grooves formed as concentric circles on the partition portion, and the ratio of the total height H to the thickness Ha of the region on the partition portion where the plurality of stress buffering portions are formed, i.e., Ha / H, is greater than 15% and less than 30%.

[0024] Effects of the Invention

[0025] According to the present invention, there are provided a sealing gasket capable of reliably absorbing stress generated when sealing the opening of a battery can of a cylindrical battery by caulking and increasing the amount of power generating elements filled in the battery can, and a cylindrical battery including the sealing gasket. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of a common alkaline battery.

[0027] Figure 2 This is a diagram showing an example of a sealing gasket assembled to the above-mentioned general alkaline battery.

[0028] Figure 3This is a diagram showing another example of a sealing gasket incorporated into the above-mentioned conventional alkaline battery.

[0029] Figure 4 It is a figure which shows the sealing gasket concerning the Example of this invention.

[0030] Figure 5 It is a figure which shows the alkaline battery provided with the sealing gasket concerning the said Example.

[0031] Figure 6 It is a figure which shows the sealing gasket which concerns on a comparative example. DETAILED DESCRIPTION

[0032] CROSS-REFERENCE TO RELATED APPLICATIONS

[0033] This application claims the benefit of priority based on Japanese Patent Application No. 2019-011488 filed on January 25, 2019, and cites the disclosure thereof.

[0034] The embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, in the drawings used for the following description, the same or similar parts are sometimes marked with the same reference numerals and repeated descriptions are omitted. Depending on the drawings, unnecessary reference numerals are sometimes omitted in the description.

[0035] ===Example==

[0036] As the gasket according to the embodiment of the present invention, there is a gasket used for LR6 alkaline batteries. Figure 4 The structure of the sealing gasket 20 according to the embodiment is shown. Figure 4 2 is a longitudinal cross-sectional view of the sealing gasket 20. Figure 4 As shown, the sealing gasket 20 involved in the embodiment is Figure 2 and Figure 3 The sealing gasket shown (hereinafter referred to as the sealing gasket 120 involved in Comparative Example 1 and the sealing gasket 220 involved in Comparative Example 2) has a stress buffer portion (130, 230) formed at one location of the partition portion 23, and stress buffer portions (30a, 30b) formed at multiple locations (two locations in this embodiment) of the partition portion 23.

[0037] Specifically, the sealing gasket 20 involved in the embodiment is made by injection molding a resin such as nylon 6 or nylon 12, and a stress buffering portion (30a, 30b) is formed on the upper surface side and the lower surface side of the partition portion 23, and the stress buffering portion (30a, 30b) is formed in the shape of an annular groove concentric with the boss portion 21. Moreover, the two stress buffering portions (30a, 30b) are formed adjacent to each other in the radial direction of the partition portion 23 via a side wall.

[0038] like Figure 4 As shown, the sealing gasket 20 according to the embodiment has a thickness Ha of the region where the stress buffering portion (30a, 30b) is formed on the partition wall portion 23. As a result, the cylindrical alkaline battery 1 having the sealing gasket 20 according to the embodiment has a larger region for accommodating the power generation element, thereby having excellent discharge capacity, and when the pressure in the battery can 2 reaches a predetermined value, the thin-walled portion 25 as a safety valve is reliably broken to ensure safety. Figure 5 FIG. 2 shows a longitudinal cross-sectional view of an LR6 alkaline battery 1 equipped with a sealing gasket 20 according to the embodiment. Figure 5 As shown, the sealing gasket 20 of the present embodiment is deformed when riveted to the open end of the battery can 2 via the negative terminal plate 7, so that the openings of the grooves constituting the two stress buffering parts (30a, 30b) are blocked (i.e., the width of the grooves is narrowed), thereby absorbing the stress in the diameter reduction direction (radial inward direction or radial direction) applied to the partition part 23. As a result, the deformation of the area of ​​the partition part 23 that is closer to the inner side than the stress buffering parts (30a, 30b) is suppressed, and the thin-walled part 25 formed around the boss part 21 can be prevented from being damaged.

[0039] ===Performance Evaluation===

[0040] Next, in order to evaluate the performance of the sealing gasket 20 according to the embodiment, a Figure 4 In the sealing gasket 20 according to the embodiment shown, various sealing gaskets (hereinafter sometimes referred to as the embodiment sample gasket 20) having different thicknesses Ha of the stress buffering portion (30a, 30b) are shown. Figure 2 The sealing gasket 120 according to the comparative example 1 shown in FIG. Figure 3 The sealing gasket 220 of Comparative Example 2 shown in FIG. Figure 6 As shown, a sealing gasket 320 according to Comparative Example 3 was also produced. The sealing gasket 320 includes only one stress buffering portion 30a of the two stress buffering portions (30a, 30b) compared to the gasket 20 of the embodiment.

[0041] In addition, Figure 2 to Figure 4 , Figure 6 In the sealing gaskets (120, 220, 20, 320) shown in each figure, the dimensions of the corresponding parts are indicated by the same reference numerals. In addition, the various sealing gaskets (120, 220, 20, 320) produced are made of the same resin material, and have the same total height H and outer diameter φ. In addition, the dimensions of the parts other than the stress buffering part (130, 230, 30a, 30b), such as the boss part (height Hb, outer diameter φ1, inner diameter φ2), the peripheral part (height Hc, thickness t), etc. are also the same.

[0042] For the gasket 20 of the embodiment, except for the thickness of the stress buffering portion (30a, 30b) (hereinafter also referred to as the buffering portion height Ha), the dimensions of each portion are the same. In addition, the depth of the groove of the two stress buffering portions (30a, 30b) in the shape of an annular groove in the gasket 20 of the embodiment is set to a dimension corresponding to the buffering portion height Ha, and is adjusted to be equal to the thickness of the portion corresponding to the groove bottom. Therefore, when the buffering portion height Ha is reduced, the depth becomes shallower. By making the thickness of the portion corresponding to the groove bottom equal, the buffering condition when the gasket 20 is riveted to the open end of the battery can 2 and deformed can be made the same.

[0043] In the region where the stress buffering portion (30a, 30b) is formed, the thickness of the thinnest portion is equal to or greater than the thickness of the thin-walled portion 25 that functions as a safety valve. In addition, the thickness of the thin-walled portion 25 of each of the manufactured gaskets (120, 220, 20, 320) is set so as to break within a predetermined pressure range based on the mechanical properties (tensile strength, compressive strength, bending strength, etc.) of the raw material (nylon 6, nylon 12, etc.) constituting each gasket (120, 220, 20, 320).

[0044] In addition, the total height H, the height Hb of the boss portion 21, the height Hc of the outer peripheral portion 24, the diameter φ, the outer diameter φ1 of the boss portion 21, the inner diameter φ2 of the boss portion 21 and the thickness t of the outer peripheral portion 24 of the various sealing gaskets (120, 220, 20, 320) produced are the same dimensions.

[0045] Furthermore, in order to evaluate the characteristics of the various sealing gaskets (120, 220, 20, 320) described above, samples were prepared in which the LR6 type battery can 2 was sealed by using various sealing bodies using these sealing gaskets (120, 220, 20, 320). Furthermore, for each sample, the volume of the storage area of ​​the power generation element (hereinafter, sometimes referred to as the volume), the operation test of the safety valve (thin-walled portion 25), and the high-temperature storage test were studied. In addition, the operation test of the safety valve was performed using a sample in which no power generation element was stored in the battery can 2, and the high-temperature storage test was performed using a sample in which a power generation element was stored in the battery can 2.

[0046] In addition, regarding the operation test and the high-temperature storage test of the safety valve (thin-walled portion 25), 20 samples of each sample were tested.

[0047] In the operation test of the safety valve (thin wall portion 25), a sample consisting of a sealed battery can 2 without containing a power generation element was used, and the pressure at which the safety valve is operated was studied while introducing compressed air into the storage area of ​​the power generation element in the sample. And, for 20 individuals belonging to the same sample, if the pressure when the safety valve breaks is within the specified numerical range, the sample is qualified, and if the safety valve breaks when even one individual among all the individuals is outside the numerical range, the sample is unqualified.

[0048] The high temperature storage test is a test for evaluating the long-term storage performance of the alkaline battery 1. The sample containing the power generation element in the battery can 2 is stored at 90°C for 30 days, and the occurrence of leakage is visually confirmed. If any one of the 20 samples leaks, the sample is considered unqualified.

[0049] The test results for each sample are shown in Table 1 below.

[0050] [Table 1]

[0051]

[0052]

[0053] In Table 1, Sample 1 is Figure 2 The alkaline battery 1 of the sealing gasket 120 of the comparative example 1 shown in the figure is provided with Figure 3 The alkaline battery 1 of the sealing gasket 220 according to Comparative Example 2 shown in FIG. Figure 6 The alkaline battery 1 of the sealing gasket 320 according to Comparative Example 3 shown in FIG. 6 is a battery having a gasket 320 having the same Figure 4 The structure shown is the same as the structure of the gasket 20 of the alkaline battery 1 of the embodiment.

[0054] In addition, "Ha / H" in Table 1 is Figure 2 to Figure 4 , Figure 6 As shown, the ratio Ha / H of the total height H of the sealing gasket (120, 220, 20, 320) to the thickness Ha of the formation area of ​​the stress buffering portion (130, 230, 30a, 30b) is shown in percentage (%). Moreover, the larger the value Ha / H is, the smaller the volume of the accommodating area of ​​the power generation element is.

[0055] In Table 1, both sample 1 and sample 2 are LR6 alkaline batteries 1 provided as products, and have almost the same volume. Moreover, Ha / H of sample 1 and sample 2 are 42% and 40% respectively. Of course, the safety valve is activated at the specified pressure and the leakage resistance test is also qualified. That is, in the sealing gaskets (120, 220) involved in comparative examples 1 and 2, the appropriate values ​​of Ha / H are 42% and 40% respectively. If Ha / H is greater than the appropriate value, the volume is reduced and it is difficult to ensure the discharge performance. On the other hand, when Ha / H is less than the appropriate value, the stress buffering part (130, 230) cannot fully absorb the stress when the battery can 2 is sealed, and the partition part 23 is easily deformed. Therefore, the pressure at which the safety valve is activated may be out of the standard. In addition, if the stress when the battery can 2 is sealed causes the partition part 23 to be normally applied with excessive stress, a part of the thin wall part 25 as the safety valve will rapidly deteriorate relative to other parts during the high temperature storage test, and leakage may also occur due to cracks in the thin wall part 25.

[0056] In the possession Figure 6 In samples 3 to 5 of the sealing gasket 320 involved in the comparative example 3 shown, the stress buffer portion (30a) of the sealing gasket (320) is formed within the thickness range of the partition portion 23, which makes it easy to increase the volume of the power generation element accommodating area. Moreover, if Ha / H ≤ 30%, the volume of the power generation element accommodating area can be increased compared with samples 1 and 2. In addition, in samples 3 to 5 having the sealing gasket 320 involved in the comparative example 3, there are individuals in which the safety valve (thin wall portion 25) breaks under pressure outside the standard, and individuals in which liquid leaks during high-temperature storage characteristics. The reason for this is considered to be that in the sealing gasket 320 involved in the comparative example 3, there is only one stress buffer portion 30a, which cannot fully absorb the stress when the battery can 2 is sealed.

[0057] In samples 6 to 10 equipped with the gasket 20 of the embodiment, the stress buffering portion (30a, 30b) of the sealing gasket 20 is formed within the thickness range of the partition portion 23, similarly to the comparative example 3, and the volume of the power generation element housing region can be easily increased. Moreover, if Ha / H≤30%, the volume of the power generation element housing region can be increased compared with samples 1 and 2. However, sample 10 with Ha / H=40% cannot obtain a larger volume than samples 1 and 2. Moreover, in samples 6 to 9 equipped with the gasket 20 of the embodiment and capable of making the volume of the power generation element housing region larger than samples 1 and 2, the safety valve (thin wall portion 25) of all individuals in samples 7 to 9 with 15%≤Ha / H≤30% broke at a pressure within the standard, and there was no individual that leaked liquid due to cracks at the safety valve during the high temperature storage test. In addition, for sample 6 with Ha / H=10%, the pressure at which the safety valve was actuated was outside the standard, or liquid leakage occurred during the high temperature storage test. This is probably because, in Sample 6, the thickness of the region where the stress buffering portion ( 30 a , 30 b ) is formed in the gasket 20 is small, and therefore, the partition wall portion 23 is greatly deformed in this region due to a slight stress change.

[0058] As described above, the sealing gasket 20 involved in the embodiment has a portion of the circular plate-shaped partition portion 23 formed with a plurality of annular groove-shaped stress buffer portions (30a, 30b) concentric with the boss portion 21, and the ratio Ha / H of the total height H to the maximum thickness Ha of the area where the stress buffer portions (30a, 30b) are formed is greater than 15% and less than 30%.

[0059] ===Other Embodiments===

[0060] In the sealing gasket 20 involved in the above-mentioned embodiment, two stress buffer portions (30a, 30b) adjacent to each other in the radial direction are alternately (alternately) formed on the upper surface (one surface) and the lower surface (the other surface) of the partition portion 23, but the two stress buffer portions (30a, 30b) can also be formed on either the upper surface or the lower surface of the partition portion 23.

[0061] The sealing gasket 20 involved in the above-mentioned embodiment has two stress buffering parts (30a, 30b), but it can also be three or more. In addition, if a plurality of stress buffering parts (30a, 30b) are provided on the partition wall part 23 whose projection area from the top and bottom directions is limited, the width of the groove constituting each stress buffering part (30a, 30b) becomes narrower, and it is difficult to ensure the molding accuracy. Therefore, the number of stress buffering parts (30a, 30b) can be appropriately determined by considering the dimensional accuracy when manufacturing the sealing gasket 20. Moreover, as shown in Table 1, even if the number of stress buffering parts (30a, 30b) is the minimum necessary two, the volume of the power generation element accommodating area is increased, and sufficient explosion-proof safety performance is ensured, so the number of stress buffering parts (30a, 30b) is more preferably two.

[0062] The sealing gasket 20 according to the above embodiment is not limited to the alkaline battery 1, but can also be applied to various cylindrical batteries in which the opening end of the battery can 2 is reduced in diameter and a sealing plate is fitted into the opening end of the battery can 2.

[0063] In addition, the above embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention can be modified and improved without departing from the spirit and scope of the present invention, and equivalent replacements thereof are all included in the protection scope of the present invention.

[0064] Description of Reference Numerals

[0065] 1 alkaline battery, 2 battery can, 3 positive electrode mixture, 4 separator, 5 negative electrode gel, 6 negative electrode collector ring, 7 negative terminal plate, 8 positive terminal, 9 crimping portion, 20, 120, 220, 320 sealing gasket, 21 boss portion, 22 boss hole, 23 partition wall portion, 24 peripheral portion, 25 thin wall portion, 30a, 30b, 130, 230 stress buffer portion.

Claims

1. A sealing gasket, the sealing gasket being used for a cylindrical battery, the cylindrical battery comprising: A metal battery can, wherein the metal battery can is in the shape of a bottomed cylinder and has an open end with an inwardly tapered diameter; a power generation element housed in the battery can, the power generation element comprising a ring-shaped positive electrode mixture disposed inside the battery can, a bottomed cylindrical separator disposed inside the positive electrode mixture, and a negative electrode gel filled inside the separator; a metal, disc-shaped sealing plate, wherein the metal, disc-shaped sealing plate is embedded in the inwardly reduced opening end; and A resin sealing gasket, the resin sealing gasket is clamped by the opening end and the sealing plate, wherein: The sealing gasket has: a disc-shaped septum; an outer peripheral portion, the outer peripheral portion being erected on the peripheral edge of the partition wall portion and being sandwiched between the opening end and the sealing plate; and a plurality of stress buffering parts, wherein when the sealing gasket is clamped by the opening end and the sealing plate, the plurality of stress buffering parts include annular grooves, the grooves being formed as concentric circles in a region between the battery can and the diaphragm of the partition wall, The stress buffering portion is formed alternately on one surface and the other surface of the partition wall portion, The ratio of the total height H from the lowest position to the highest position of the sealing gasket to the thickness Ha of the region on the partition wall where the plurality of stress buffering portions are formed, i.e., Ha / H, is 15% or more and 30% or less. The depth of the annular groove in the plurality of stress buffering portions is a dimension corresponding to the thickness Ha of the region, The thicknesses of the portions of the plurality of stress buffering portions corresponding to the annular groove bottom are equal.

2. The sealing gasket according to claim 1, wherein: The sealing gasket includes two stress buffering portions.

3. A cylindrical battery, comprising: A metal battery can, wherein the metal battery can is in the shape of a bottomed cylinder and has an open end with an inwardly tapered diameter; a power generation element housed in the battery can, the power generation element comprising a ring-shaped positive electrode mixture disposed inside the battery can, a bottomed cylindrical separator disposed inside the positive electrode mixture, and a negative electrode gel filled inside the separator; a metal, disc-shaped sealing plate, wherein the metal, disc-shaped sealing plate is embedded in the inwardly reduced opening end; and A resin sealing gasket, the resin sealing gasket is clamped by the opening end and the sealing plate, wherein: The sealing gasket has: a disc-shaped septum; an outer peripheral portion, the outer peripheral portion being erected on the peripheral edge of the partition wall portion and being sandwiched between the opening end and the sealing plate; and a plurality of stress buffering parts, wherein when the sealing gasket is clamped by the opening end and the sealing plate, the plurality of stress buffering parts include annular grooves, the grooves being formed as concentric circles in a region between the battery can and the diaphragm of the partition wall, The stress buffering portion is formed alternately on one surface and the other surface of the partition wall portion, The ratio of the total height H from the lowest position to the highest position of the sealing gasket to the thickness Ha of the region on the partition wall where the plurality of stress buffering portions are formed, i.e., Ha / H, is 15% or more and 30% or less. The depth of the annular groove in the plurality of stress buffering portions is a dimension corresponding to the thickness Ha of the region, The thicknesses of the portions of the plurality of stress buffering portions corresponding to the annular groove bottom are equal.

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