Sealed battery

Abstract

A sealed battery includes an electrode body, an outer can (16), a sealing body, and a gasket (28) interposed between the outer can and the sealing body. The sealing body is chiseled and fixed to the opening-side end of the outer can with the gasket interposed therebetween. The gasket has a cylindrical body section (50) and a protrusion section (54) that protrudes radially outward from the outer peripheral surface of the body section over the entire circumference. The protrusion is elastically bent to the axial outer side in a manner that the front end is close to the outer peripheral surface of the main body part in a state that a force is applied to the inner peripheral surface of a cylinder part arranged at the end part of the opening side of the outer packaging can to the radial outer side.

Description

Technical Field

[0001] This application relates to a sealed battery, and more particularly to a configuration in which a gasket is sandwiched between the open end of the outer packaging can and the sealing body is tightly fixed, with the intention of simultaneously improving the ability to remove electrolyte from the inner surface of the open end of the outer packaging can and improving the insertability of the gasket into the outer packaging can. Background Technology

[0002] Conventional sealed batteries are known to consist of an electrode body, a bottomed cylindrical outer packaging can housing the electrode body, and a sealing body that seals the opening of the outer packaging can. In such sealed batteries, electrolyte is sometimes injected before the sealing body is installed into the outer packaging can. However, if electrolyte remains adhering to the inner surface of the open end of the outer packaging can after injection, the electrolyte adhering to the outer packaging can may cause corrosion of the outer packaging can, or may cause electrolyte to leak out of the outer packaging can.

[0003] Patent Document 1 describes a sealed battery in which a sealing body is tightly fixed to the open end of the outer packaging can by a resin liner with insulating properties. In the configuration described in Patent Document 1, the sealed battery has a trapezoidal, mountain-shaped protrusion extending radially outward on the outer circumferential surface of the liner, which abuts against the inner circumferential surface of the open end of the outer packaging can. When the sealing body and the liner are inserted together into the open end of the outer packaging can with the open end extending axially, the protrusion of the liner abuts against the inner circumferential surface of the open end, and electrolyte adhering to the inner circumferential surface is scraped off by the protrusion.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2021 / 200439 Summary of the Invention

[0007] According to the configuration described in Patent Document 1, when the liner is inserted into the outer packaging can, it is possible to scrape off the electrolyte remaining on the inner surface of the open end of the outer packaging can using the protrusion of the liner, thereby reducing the amount of electrolyte adhering to the open end of the outer packaging can. However, for the liner described in Patent Document 1, if the outer diameter of the protrusion is made excessively larger than the inner diameter of the open end of the outer packaging can in order to increase the amount of electrolyte scraped off, then when the liner is inserted into the inner side of the open end, a large radial force is required to compress the protrusion. Therefore, there is still room for improvement in terms of improving the can insertion performance of the liner. On the other hand, if the outer diameter of the liner protrusion is made approximately the same as the inner diameter of the open end of the outer packaging can in order to improve the can insertion performance, it is difficult to increase the amount of electrolyte scraped off. Therefore, there is still room for improvement in terms of improving the ability to remove electrolyte from the inner surface of the outer packaging can.

[0008] Therefore, the purpose of this application is to provide a sealed battery, which is configured to clamp and fix the sealing body with a gasket at the open end of the outer packaging can, thereby simultaneously improving the ability to remove electrolyte from the inner surface of the open end of the outer packaging can and improving the insertability of the gasket into the outer packaging can.

[0009] The sealed battery of this application comprises: an electrode body formed by winding a positive electrode and a negative electrode together with a spacer between them; a bottomed cylindrical outer packaging can containing the electrode body and an electrolyte; a sealing body that seals the opening of the outer packaging can; and an annular gasket sandwiched between the outer packaging can and the sealing body. The sealing body is clamped and fixed to the opening end of the outer packaging can with the gasket between them. The gasket includes a cylindrical main body and a protrusion that protrudes radially outward from the outer circumference of the main body. When a force is applied radially outward to the inner circumference of the cylindrical part located at the opening end of the outer packaging can, the protrusion is elastically bent axially outward with its front end close to the outer circumference of the main body.

[0010] According to the sealed battery of this application, when the gasket is inserted into the outer packaging can, the force exerted by the protrusion on the inner circumferential surface of the open end of the outer packaging can is ensured, while the elastic bending of the protrusion outward in the axial direction improves the insertability of the gasket into the outer packaging can. Thus, both the ability to remove electrolyte from the inner surface of the open end of the outer packaging can and the insertability of the gasket into the outer packaging can be improved simultaneously. Attached Figure Description

[0011] Figure 1 This is an axial cross-sectional view of a sealed battery according to one embodiment of this application.

[0012] Figure 2 yes Figure 1Enlarged view of part A.

[0013] Figure 3 This is a cross-sectional view of the liner before it is inserted into the outer packaging can in the embodiment.

[0014] Figure 4 This diagram illustrates the process of inserting the liner into the outer packaging can in an embodiment.

[0015] Figure 5 This is a partial cross-sectional view showing the initial state when the liner is inserted into the outer packaging can in the embodiment.

[0016] Figure 6 This is a comparative example of a sealed battery. Figure 4 The diagram corresponding to (a).

[0017] Figure 7 In another example of the implementation method, with Figure 2 The corresponding diagram.

[0018] Figure 8 In another example of the implementation method, with Figure 5 The corresponding diagram. Detailed Implementation

[0019] Hereinafter, embodiments of the sealed battery of this application will be described in detail with reference to the accompanying drawings. It should be noted that the sealed battery of this application can be a primary battery or a secondary battery. Furthermore, it can be a battery using an aqueous electrolyte or a battery using a non-aqueous electrolyte. Hereinafter, a secondary battery (lithium-ion battery) using a non-aqueous electrolyte will be illustrated as one embodiment of the sealed battery.

[0020] From the outset, it was envisioned that new embodiments could be constructed by appropriately combining the characteristic features of the following described embodiments and variations. In the following embodiments, the same symbols are used to label the same components in the drawings, and repeated descriptions are omitted. Furthermore, the multiple drawings include schematic diagrams, and the aspect ratios of the components (longitudinal, transverse, height, etc.) may not be consistent between different drawings. Additionally, among the constituent elements described below, those not described in the independent technical solution representing the highest-level concept are optional, not essential. Moreover, this application is not limited to the following embodiments and variations; various modifications and alterations can be made within the scope of the technical solutions described in this application and their equivalents.

[0021] Figure 1 This is an axial cross-sectional view of a sealed battery 10 as an example of an implementation. Figure 2 yes Figure 1 An enlarged view of part A. (See image below.) Figure 1As shown, the sealed battery 10 has a positive electrode 11, a negative electrode 12, and a spacer 13, and includes an electrode body 14 formed by winding the positive electrode 11 and the negative electrode 12 together with the spacer 13 in between. Additionally, the sealed battery 10 includes a bottomed cylindrical outer packaging can 16 for housing the electrode body 14, and a sealing body 17 for sealing the opening of the outer packaging can 16. The outer packaging can 16 contains the electrode body 14 along with a non-aqueous electrolyte.

[0022] The outer packaging can 16 is a bottomed cylindrical metal container with a cylindrical portion 30 and a bottom 31 located at one axial end of the cylindrical portion 30. The outer packaging can 16 has a slotted portion 34, described later, formed on the other axial end side, which is the opening end side of the cylindrical portion 30. The sealing body 17 is supported by the slotted portion 34 and seals the opening of the outer packaging can 16. Hereinafter, for ease of explanation, the sealing body 17 side of the sealed battery 10 will be described as upper, and the bottom 31 side of the outer packaging can 16 will be described as lower.

[0023] The non-aqueous electrolyte has ionic conductivity (e.g., lithium-ion conductivity). The non-aqueous electrolyte comprises a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. The sealed battery 10 is preferably a lithium-ion battery. The electrolyte salt may be, for example, lithium salts such as LiBF4 and LiPF6. The non-aqueous solvent may be, for example, esters, ethers, nitriles, amides, or mixtures of two or more of the above solvents, such as ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and methyl propionate (MP). The non-aqueous solvent may also contain halogen-substituted products obtained by replacing at least a portion of the hydrogen atoms in these solvents with halogen atoms such as fluorine.

[0024] Examples of halogen substitutes include fluorocyclic carbonates such as fluoroethylene carbonate (FEC), fluorochain carbonates, and fluorochain carboxylic acid esters such as methyl fluoropropionate (FMP). From the perspective of suppressing the degradation of charge-discharge cycle characteristics of sealed batteries or improving input characteristics, the non-aqueous electrolyte preferably contains 5% by mass or more of FEC relative to the mass of the non-aqueous electrolyte, and more preferably contains 5% to 15% by mass of FEC.

[0025] As described above, the electrode body 14 has a spiral structure in which a positive electrode 11 and a negative electrode 12 are wound together in a spiral shape and sandwiched between spacers 13. The positive electrode 11, the negative electrode 12, and the spacers 13 are all strip-shaped elongated bodies, which are alternately stacked radially along the electrode body 14 by being wound into a spiral shape. To prevent lithium deposition, the negative electrode 12 is formed with a size one size larger than the positive electrode 11. That is, the negative electrode 12 is formed to be longer in both the length and width directions than the positive electrode 11. The spacers 13 are formed with a size at least one size larger than the positive electrode 11, for example, two spacers are arranged to clamp the positive electrode 11.

[0026] A positive terminal 20 and a negative terminal 21 are connected to the electrode body 14. The positive terminal 20 electrically connects the positive electrode 11 to the sealing body 17. The positive terminal 20 is located at the center of the positive electrode 11 along its length and away from the winding start end and winding end end of the electrode body 14.

[0027] The negative electrode connector 21 is engaged with the exposed core portion located at the winding start side end, which is the longitudinal end of the negative electrode 12 located at the winding start side of the negative electrode 12. Figure 1 In the example shown, the positive terminal 20 extends towards the sealing body 17 after passing through the opening of the upper insulating plate 18, and joins the lower surface of the sealing body 17, thus making the sealing body 17 the positive terminal. The negative terminal 21 passes through the through hole of the annular lower insulating plate 19 and is bent along the inner surface of the bottom 31 of the outer packaging can 16, and is connected to the inner surface of the bottom of the outer packaging can 16 by welding or the like, thus making the outer packaging can 16 the negative terminal.

[0028] A negative electrode 12 is disposed on the outermost circumferential surface of the electrode body 14, and the exposed portion of the surface of the negative electrode core constituting the negative electrode 12 (described later) abuts against the inner circumferential surface of the outer packaging can 16. Thus, the two ends of the negative electrode 12 in the longitudinal direction are electrically connected to the outer packaging can 16, ensuring good current collection.

[0029] The positive electrode 11 has a positive electrode core and positive electrode binder layers formed on both sides of the core. The positive electrode core can be a foil of a metal stable within the potential range of the positive electrode 11, such as aluminum or an aluminum alloy, or a film of the same metal disposed on its surface. The positive electrode binder layers contain a positive electrode active material, a conductive agent such as acetylene black, and a binder such as polyvinylidene fluoride (PVdF), and are preferably formed on both sides of the positive electrode core. The thickness of the positive electrode binder layer is, for example, 40 μm or more and 100 μm or less. The positive electrode active material is, for example, a lithium transition metal composite oxide containing Ni, Co, Mn, Al, etc. It should be noted that the positive electrode connector 20 is preferably directly bonded to the positive electrode core by ultrasonic welding or the like.

[0030] The negative electrode 12 has a negative electrode core and negative electrode binder layers formed on both sides of the negative electrode core. The negative electrode core can be a foil of a metal stable within the potential range of the negative electrode 12, such as copper or a copper alloy, or a film of that metal disposed on its surface. The negative electrode binder layers contain a negative electrode active material and a binder such as styrene-butadiene rubber (SBR). The thickness of the negative electrode binder layer is, for example, 40 μm or more and 100 μm or less. The negative electrode active material is, for example, graphite or a Si-containing material. The negative electrode connector 21 is preferably directly bonded to the negative electrode core by ultrasonic welding or the like.

[0031] An annular gasket 28 is sandwiched between the outer packaging can 16 and the sealing body 17. The sealing body 17 is clamped and fixed to the upper end of the outer packaging can 16, which is the open side end, through the gasket 28. Specifically, a radially curved portion 38 is formed at the upper end of the outer packaging can 16, which bends radially inward throughout its entire circumference, thereby clamping and fixing the upper end of the outer packaging can 16 to the periphery of the sealing body 17 through the gasket 28. As a result, the inside of the battery is sealed.

[0032] Furthermore, the outer packaging can 16 has a slotted portion 34 formed, for example, by pressing the side portion from the outside, which supports the sealing body 17. The slotted portion 34 is preferably formed in a ring shape along the circumferential direction of the outer packaging can 16, and its upper surface supports the sealing body 17.

[0033] The sealing body 17 has a structure in which an inner terminal plate 23, a lower valve body 24, an insulating member 25, an upper valve body 26, and a cover 27 are stacked sequentially from the electrode body 14 side. Each component constituting the sealing body 17 is, for example, circular or annular, and all components except the insulating member 25 are electrically connected to each other. The cover 27 is a cap-shaped structure with an annular flange 27b on its outer periphery and a closed cylindrical portion 27c at its center. The inner terminal plate 23 has multiple openings 23a extending vertically. The lower valve body 24 and the upper valve body 26 are connected to each other at their respective centers, and the insulating member 25 is sandwiched between their respective peripheries. The flange portion 17a of the sealing body 17 is formed by the flange 27b of the cover 27 and the portions of the components of the sealing body 17 other than the cover 27 that overlap with the flange 27b along the axial direction. The flange portion 17a is an annular portion located on the outer periphery of the sealing body 17.

[0034] When the internal pressure of the battery rises, the lower valve body 24 deforms and breaks by pushing the upper valve body 26 toward the cover 27, thereby blocking the current path between the lower valve body 24 and the upper valve body 26. When the internal pressure rises further, the upper valve body 26 breaks, and gas is discharged from the opening 27a of the cover 27.

[0035] As described above, in the configuration where the sealing body 17 is secured by a gasket 28 at the open end of the outer packaging can 16, during battery manufacturing, electrolyte is injected into the interior of the outer packaging can 16 from the open end before securing the sealing body 17 to the open end of the outer packaging can 16. However, if electrolyte remains on the inner surface of the open end of the outer packaging can 16 after injection, the electrolyte adhering to the outer packaging can 16 may cause corrosion of the outer packaging can 16 or may cause electrolyte to leak out of the outer packaging can 16.

[0036] Furthermore, if, as described in Patent Document 1, the electrolyte residue adhering to the inner surface of the opening end of the outer packaging can is scraped off by a trapezoidal, mountain-shaped protrusion of the gasket when the gasket is inserted into the outer packaging can, then there is still room for improvement in terms of simultaneously improving the ability to remove electrolyte from the inner surface of the opening end of the outer packaging can and improving the insertability of the gasket into the outer packaging can. Therefore, in this embodiment, as described later, a protrusion 54 is provided that protrudes radially outward from the outer peripheral surface of the cylindrical main body 50 of the gasket 28. Using the protrusion 54, when a force is applied radially outward to the inner peripheral surface of the cylindrical part of the outer packaging can 16, the protrusion 54 is elastically bent axially outward so that its front end 55 is close to the outer peripheral surface of the main body 50.

[0037] The following uses Figures 2-5 The composition of the gasket 28 is described in detail. Figure 3 This is a cross-sectional view of the liner 28 before it is inserted into the outer packaging can 16. Figure 4 This diagram shows the process of inserting the liner 28 into the outer packaging can 16. Figure 5 This is a partial cross-sectional view showing the initial state when the liner 28 is inserted into the outer packaging can 16.

[0038] like Figures 1-2 As shown, the gasket 28 is formed of resin with a generally C-shaped cross-section and a generally annular shape when viewed from above. Specifically, the gasket 28 has a cylindrical main body portion 50 located at its outer periphery, an inner annular plate portion 51 connected to the axially inner end of the main body portion 50 and extending radially inward, and an outer annular plate portion 52 connected to the axially outer end of the main body portion 50 and extending radially inward. The main body portion 50 is formed in a generally cylindrical shape. Figure 1 In the outer packaging can 16, the radially inner end of the radially curved portion 38 is approximately aligned with the radially inner end of the outer annular plate portion 52. It should be noted that an extension portion extending radially inward beyond the radially inner end of the radially curved portion 38 may also be formed in the outer annular plate portion 52.

[0039] The liner 28 can be made of a flexible, insulating resin. Examples of such resins include polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), perfluoroalkoxy fluoropolymer (PFA), and nylon.

[0040] In this embodiment, such as Figure 2 As shown, the gasket 28 has a protrusion 54 that protrudes radially outward from the outer circumference of the cylindrical main body 50. The protruding position of the protrusion 54 is a portion of the outer circumference of the main body 50 that is axially inward than the axially outer side of the flange portion 17a of the sealing body 17. Figure 2The flange portion 17a is omitted from the illustration.

[0041] The protrusions 54 are provided in the cylindrical portion 30 of the outer packaging can 16, on the inner circumferential surface of the upper cylindrical portion 30a adjacent to the upper side of the slotted portion 34, serving as the radially outer side. Figure 2 A force is applied in the direction of arrow α. In this state, the protrusion 54 is elastically bent outward in an axial direction such that the front end 55 is brought close to the outer peripheral surface of the main body 50. Because the protrusion 54 is elastically bent, a force is generated in the protrusion 54 that attempts to elastically restore the front end 55 to the radial direction. As a result, the protrusion 54 applies a force to the inner peripheral surface of the upper cylindrical portion 30a in a radial direction. Therefore, as will be described later, the ability to remove electrolyte from the inner surface of the opening side end of the outer packaging can 16 and the insertion capability of the gasket 28 into the outer packaging can 16 can be improved simultaneously.

[0042] Furthermore, a gap 60 is formed between the protrusion 54 and the outer peripheral surface of the main body 50. Figure 2 The gap 60 is an annular gap with a roughly triangular cross-section that is continuous throughout the entire circumference between the protrusion 54 and the outer peripheral surface of the main body 50. Therefore, when the gasket 28 is inserted into the outer packaging can 16 as described later, the protrusion 54 is less likely to be compressed by the outer peripheral surface of the main body 50 and the outer packaging can 16, thus preventing excessive compression of the protrusion 54 by the outer packaging can 16. Therefore, the insertability of the gasket 28 into the outer packaging can 16 can be further improved.

[0043] With the gasket 28 installed in the outer packaging can 16, in order to form the gasket 28 as described above, such as Figure 3 As shown, the liner 28, before being inserted into the outer packaging can 16, is formed into an annular shape with a roughly L-shaped cross-section, having a cylindrical portion 50a and an inner annular plate portion 51. Both the inner and outer circumferential surfaces of the cylindrical portion 50a are tapered, causing its inner and outer diameters to gradually increase towards the axially outward direction. The maximum outer diameter d1 of the axially outer end of the cylindrical portion 50a is greater than that described later. Figure 5 The inner diameter d2 of the upper cylindrical portion 30c extending axially before the outer packaging can 16 is shown. Since the outer peripheral surface of the cylindrical portion 50a of the gasket 28 is tapered and inclined in this way, the gasket 28 is inserted into the upper cylindrical portion 30c of the outer packaging can 16 before it is tightened.

[0044] Furthermore, a protrusion 54 protrudes from the bottom side end along the entire circumference of the outer peripheral surface of the cylindrical portion 50a of the gasket 28. The protrusion 54 is a disc-shaped protrusion that extends radially outward and axially outward along the entire circumference of the outer peripheral surface of the cylindrical portion 50a.

[0045] On the outer peripheral surface of the cylindrical portion 50a, the portion adjacent to the axially outer side of the root position of the protrusion 54 is curved in a shape where the outer diameter decreases towards the bottom side end. The protrusion 54 protrudes radially outward from the portion of the cylindrical portion 50a with the smallest outer diameter.

[0046] Furthermore, before the gasket 28 is installed onto the outer packaging can 16, the outer diameter d3 of the portion of the gasket 28 including the front end 55 of the protrusion 54 is larger than the inner diameter d2 of the axially extending upper cylindrical portion 30c of the outer packaging can 16 before it is tightened (see below). Figure 5 Therefore, as Figure 2 As shown, while the protrusion 54 can be elastically bent close to the outer peripheral surface of the main body 50, the inner surface of the upper cylindrical portion 30a of the outer packaging can 16 is subjected to a force radially outward by the protrusion 54 when the liner 28 is installed on the outer packaging can 16.

[0047] Below, with appropriate reference Figures 1-3 At the same time, use Figure 4 , Figure 5 The method for securing the sealing body 17 by chiseling the gasket 28 between the outer packaging can 16 and the sealing body 17 will be described. First, in the outer packaging can 16, a portion of the cylindrical part before chiseling at the open end is radially recessed inward by spinning, thereby forming a slotted portion 34. An upper cylindrical part 30c is formed above this slotted portion 34. Then, electrolyte is injected into the outer packaging can 16 from the upper side of its open end inward. At this time, as... Figure 4 As shown in (a), sometimes residues may remain. Figure 4 The electrolyte 70 shown in the sand diagram in (a) remains on the inner surface near the corner between the annular plate portion 34a, which forms the upper end of the slotted portion 34 and extends radially inward toward the battery, and the upper cylindrical portion 30c.

[0048] Then, as Figure 4 As indicated by arrow β in (a), the gasket 28 is inserted together with the sealing body into the upper cylindrical portion 30c of the outer packaging can 16 from the upper side, which is the axial outer end side. Figure 4 The diagram of the sealing body is omitted. At this point, as explained above, due to... Figure 5 The outer diameter d3 of the portion of the pad 28, including the front end 55 of the protrusion 54, is greater than the inner diameter d2 of the upper cylindrical portion 30c of the outer packaging can 16. Therefore, as the pad 28 is inserted into the outer packaging can 16, the protrusion 54 is elastically bent in such a way that the front end 55 is brought close to the outer peripheral surface of the cylindrical portion 50a.

[0049] After that, as Figure 4As shown in (b), while the electrolyte 70 remaining near the corner between the annular plate portion 34a and the upper cylindrical portion 30c of the outer packaging can 16 is scraped downwards by the protrusion 54, the gasket 28 is inserted into the inner side of the upper cylindrical portion 30c. At this time, the outer peripheral surface of the upper end of the cylindrical portion 50a of the gasket 28 is also pressed against the inner surface of the upper cylindrical portion 30c of the outer packaging can 16. Thereafter, as... Figure 4 As shown in (c), with the protrusion 54 applying a force radially outward to the inner surface of the upper cylindrical portion 30c, a liner 28 is disposed on the upper surface of the annular plate portion 34a. Therefore, electrolyte 70 remaining near the aforementioned corner and adhering to the inner surface of the outer packaging can 16 can be scraped off to the vicinity of the upper surface of the annular plate portion 34a. Furthermore, since the inner annular plate portion 51 of the liner 28 is pressed against the upper surface of the annular plate portion 34a, electrolyte 70 can be squeezed radially inward from between the inner annular plate portion 51 and the annular plate portion 34a.

[0050] Subsequently, the open end of the outer packaging can 16 and the upper part of the cylindrical portion 50a of the gasket 28 are radially tightened around the entire circumference. Between the radially curved portion 38 formed by this tightening and the upper surface of the slotted portion 34, the outer periphery of the flange portion 17a of the sealing body 17 is clamped through the gasket 28, thereby fixing the sealing body 17 to the outer packaging can 16.

[0051] According to the aforementioned sealed battery 10, when the gasket 28 is inserted into the outer packaging can 16, the force exerted by the protrusion 54 on the inner circumferential surface of the open end of the outer packaging can 16 can be ensured. Simultaneously, the elastic bending of the protrusion 54 outward in the axial direction can enhance the insertability of the gasket 28 into the outer packaging can 16. Therefore, both the ability to remove electrolyte from the inner surface of the open end of the outer packaging can 16 and the insertability of the gasket 28 into the outer packaging can 16 can be simultaneously improved.

[0052] Furthermore, the protruding part 54 is located on the outer peripheral surface of the main body 50, further axially inward than the axially outer side of the flange 17a of the sealing body 17. Therefore, it is possible to prevent the protruding part 54 from being compressed between itself and the upper side of the flange 17a by the radially bent part 38, thereby preventing a decrease in the sealing performance of the sealing body 17.

[0053] Furthermore, since the protrusion of the protrusion 54 is located at the axial inner end of the outer peripheral surface of the main body 50, more electrolyte adhering to the inner surface of the opening side end of the outer packaging can 16 can be scraped off to the vicinity of the slotted portion 34.

[0054] It should be noted that the protruding position of the protrusion 54 can also be located on the outer peripheral surface of the main body 50 in a range that is further axially inner than the axially outer side of the flange 17a of the sealing body 17 and further axially outer than the axially inner end of the outer peripheral surface of the main body 50.

[0055] Figure 6 This is a comparative example of a sealed battery. Figure 4 Figure (a) corresponds to the figure. The comparative example liner 28a has the same shape as the liner described in Patent Document 1. Specifically, the comparative example liner 28a, in its state before being inserted into and tightened at the open end of the outer packaging can 16a, is formed as an annular shape with a generally L-shaped cross-section, having a cylindrical portion 62 and an inner annular plate portion 61 protruding radially inward from the bottom end of the cylindrical portion 62. In addition, a trapezoidal protrusion 63 protrudes throughout the entire circumference from near the bottom of the outer peripheral surface of the cylindrical portion 62. The outer diameter of the liner 28a, including the front end of the protrusion 63, is the same as or larger than the inner diameter of the upper cylindrical portion 30c extending axially before tightening the outer packaging can 16a.

[0056] Figure 6 In, with Figure 4 Similarly, (a) shows the initial state of the process of installing the gasket 28 in the outer packaging can 16a. At this time, the gasket 28, which has an approximately L-shaped cross-section and is annular, is inserted into the inner side of the axially extending upper cylindrical portion 30c of the outer packaging can 16. Even in this comparative example, it is possible to use the protrusion 63 to scrape off the electrolyte residue adhering to the inner surface of the upper cylindrical portion 30c of the outer packaging can 16.

[0057] However, in the comparative example of the gasket 28a, if the outer diameter of the protrusion 63 is made excessively larger than the inner diameter of the upper cylindrical portion 30c of the outer packaging can 16a in order to increase the amount of electrolyte scraped off, then when the gasket 28a is inserted into the inner side of the upper cylindrical portion 30c, the protrusion 63 needs to be compressed radially by the outer packaging can 16a with a large force. As a result, the resistance when inserting the gasket 28a into the outer packaging can 16a increases. Therefore, in the comparative example, there is still room for improvement in terms of simultaneously improving the ability to remove electrolyte from the inner surface of the open end of the outer packaging can 16a and improving the insertability of the gasket 28a into the outer packaging can 16a.

[0058] According to this embodiment, since the protrusion 54 that applies force to the inner surface of the outer packaging can 16 is formed when the gasket 28 is bent, the adverse situation described above can be prevented, and the ability to remove electrolyte from the inner surface of the opening side end of the outer packaging can 16 and the insertability of the gasket 28 into the outer packaging can 16 can be improved at the same time.

[0059] Figure 7 In another example of the implementation method, with Figure 2The corresponding figure. In this example, the main body 50 of the pad 28b has an annular recess 56 with a generally rectangular cross-section that is continuous throughout the entire circumference, formed on the outer peripheral surface of the axial inner end on the bottom side. In addition, a protrusion 54a protrudes adjacent to the lower end of the inner surface of the recess 56, and the protrusion 54a protrudes radially and axially outward from the bottom side end of the outer peripheral surface of the main body 50.

[0060] Furthermore, in this state, the protrusion 54a is elastically bent closer to the axially outer side than the root end of the protrusion 54a on the outer peripheral surface of the main body 50, and a force is applied radially outward to the inner surface of the upper cylindrical portion 30a of the outer packaging can 16. As a result, a recess 56 is formed on the outer peripheral surface of the main body 50 at the portion radially opposite to the protrusion 54a. Additionally, a portion of the protrusion 54a enters the recess 56, and a gap 64 is formed radially between the protrusion 54a and the outer peripheral surface of the main body, which serves as the inner surface of the recess 56.

[0061] According to the configuration of the other example described above, by increasing the amount of protrusion of the protrusion 54 from the outer peripheral surface of the main body 50, even when the protrusion 54 is significantly bent radially toward the outer peripheral surface of the main body 50 while the gasket 28 is being installed in the outer packaging can 16, it is easy to form a gap 64 radially between the protrusion 54 and the inner surface of the recess 56. Therefore, the electrolyte removal capacity can be further improved without reducing the insertability of the gasket 28 into the outer packaging can 16. In this example, other configurations and functions are similar to... Figures 1-5 They have the same composition.

[0062] Figure 8 In another example of the implementation method, with Figure 5 The corresponding diagram. In this example, before the gasket 28c is installed on the outer packaging can 16, in the main body 50, a radially protruding protrusion 54b protrudes radially outward from the outer circumference of the bottom side end, i.e., the axial inner end.

[0063] The outer diameter of the gasket 28c, including the front end of the protrusion 54b, is larger than the inner diameter of the upper cylindrical portion 30c of the outer packaging can 16 before it is tightened. Even when the gasket 28c has this shape before being installed into the outer packaging can 16, as the gasket 28c is inserted into the open end of the outer packaging can 16, the protrusion 54b bends towards the outer peripheral surface of the main body 50, and in this state, it can apply a force radially outward to the inner surface of the upper cylindrical portion 30c of the outer packaging can 16. In this example, other components and functions are similar to... Figures 1-5 They have the same composition.

[0064] This application is further illustrated by the following embodiments.

[0065] Component 1: A sealed battery, comprising:

[0066] An electrode body formed by winding the positive and negative electrodes together with spacers between them.

[0067] A bottomed cylindrical outer packaging can containing the aforementioned electrode body and electrolyte.

[0068] The sealing body that blocks the opening of the aforementioned outer packaging can, and

[0069] An annular gasket sandwiched between the outer packaging can and the sealing body.

[0070] The sealing body is clamped and secured to the open end of the outer packaging can, with the gasket in between.

[0071] The aforementioned pad includes a cylindrical main body and a protrusion that projects radially outward from the outer circumference of the main body.

[0072] When the aforementioned protrusion is subjected to a force on the inner circumferential surface of the cylindrical portion located at the opening side end of the aforementioned outer packaging can in a radially outward manner, the aforementioned protrusion is elastically bent outward in a manner with its front end close to the outer circumferential surface of the aforementioned main body portion.

[0073] Configuration 2: According to the sealed battery described in Configuration 1, a gap is formed between the aforementioned protrusion and the radial direction of the outer peripheral surface of the aforementioned main body.

[0074] Configuration 3: A sealed battery according to Configuration 1 or Configuration 2, wherein an annular recess is formed on the outer peripheral surface of the main body portion in a radially opposite portion to the protrusion.

[0075] At least a portion of the aforementioned protrusion enters the aforementioned recess.

[0076] Configuration 4: A sealed battery according to any one of Configurations 1 to 3, wherein the sealing body has an annular flange portion provided on the outer peripheral side.

[0077] The aforementioned protrusion protrudes from the portion located further axially inward than the axially outer side of the aforementioned flange portion on the outer peripheral surface of the aforementioned main body portion.

[0078] Configuration 5: According to the sealed battery described in Configuration 4, wherein the protrusion protrudes from the inner end of the outer peripheral surface of the main body.

[0079] Explanation of reference numerals in the attached figures

[0080] 10 Sealed battery, 11 Positive electrode, 12 Negative electrode, 13 Spacer, 14 Electrode body, 16, 16a Outer packaging can, 17 Sealing body, 17a Flange, 18 Upper insulating plate, 19 Lower insulating plate, 20 Positive terminal, 21 Negative terminal, 23 Internal terminal plate, 24 Lower valve body, 25 Insulating component, 26 Upper valve body, 27 Cover, 27a Opening, 27b Flange, 27c Cylindrical part, 28, 28a, 28b, 28c Gasket, 30 Cylindrical part, 30a, 30c Upper cylindrical part, 31 Bottom, 34 Slotted part, 38 Radial bending part, 50 Main body, 50a Cylindrical part, 51 Inner annular plate, 52 Outer annular plate, 54, 54a, 54b Protrusion, 55 Front end, 56 Recess, 61 Inner annular plate, 62 Cylindrical part, 63 Protrusion, 64 Gap, 70 Electrolyte.

Claims

1. A sealed battery, comprising: An electrode body formed by winding the positive and negative electrodes together with spacers between them. A bottomed cylindrical outer packaging can containing the electrode body and electrolyte. A sealing body that blocks the opening of the outer packaging can, and An annular gasket sandwiched between the outer packaging can and the sealing body. The sealing body is clamped and secured to the open end of the outer packaging can through the gasket. The gasket includes a cylindrical main body and a protrusion that projects radially outward from the outer circumference of the main body. With respect to the protrusion, when a force is applied radially outward to the inner circumferential surface of the cylindrical portion located at the open end of the outer packaging can, it is elastically bent axially outward with its front end close to the outer circumferential surface of the main body.

2. The sealed battery according to claim 1, wherein, A gap is formed radially between the protrusion and the outer peripheral surface of the main body.

3. The sealed battery according to claim 1, wherein, On the outer peripheral surface of the main body, an annular recess is formed at the portion facing the protrusion radially. At least a portion of the protrusion enters the recess.

4. The sealed battery according to claim 1, wherein, The sealing body has an annular flange on its outer periphery. The protrusion extends from the portion located axially inward than the axially outer side of the flange portion on the outer peripheral surface of the main body portion.

5. The sealed battery according to claim 4, wherein, The protrusion protrudes from the inner end of the outer peripheral surface of the main body.

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