Cylindrical battery

Abstract

The cylindrical battery includes: an electrode body (10); a bottomed cylindrical outer can (20) containing the electrode body (10) and electrolyte; and a sealing body (30) that seals the opening of the outer can (20), and includes a positive electrode lead (11) connected to the positive electrode constituting the electrode body (10). The cylindrical battery also includes: an annular positive electrode current collector (40) that connects the positive electrode lead (11) and is welded to the outer can (20); and a gasket (50) disposed between the outer can (20) and the sealing body (30) and covering the lower surface of the positive electrode current collector (40) facing the electrode body (10). The gasket (50) has an inner peripheral wall portion (51) that covers the inner peripheral surface (44) of the periphery forming the opening (41) of the positive electrode current collector (40).

Description

Technical Field

[0001] This disclosure relates to cylindrical batteries. Background Technology

[0002] Generally, a cylindrical battery has the following structure: a wound electrode body with a positive and negative electrode wound in a spiral shape and separated by a spacer; a bottomed cylindrical outer can containing the electrode body; and a sealing body that seals the opening of the outer can, with leads extending from the electrode body connected to the sealing body (see, for example, Patent Document 1). Furthermore, the cylindrical battery of Patent Document 1 includes: an annular current collector that connects the leads and is welded to the sealing body; and a gasket disposed between the outer can and the sealing body.

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: International Publication No. WO2022 / 270432 Summary of the Invention

[0006] However, cylindrical batteries, for example, are manufactured by housing the electrode body and current collector in an outer can and injecting electrolyte, followed by welding the sealing body and current collector together. However, through research by the inventors, it was discovered that electrolyte adhering to the current collector can cause welding defects. When welding the sealing body and current collector, if electrolyte is present at the welding point, welding defects can occur due to the influence of the vaporized electrolyte.

[0007] The cylindrical battery disclosed herein comprises: an electrode body; a bottomed cylindrical outer can containing the electrode body and an electrolyte; and a sealing body that seals the opening of the outer can. The cylindrical battery includes leads connected to electrodes constituting the electrode body. The cylindrical battery is characterized in that it further comprises: an annular current collector connecting the leads and welded to the sealing body; and a gasket disposed between the outer can and the sealing body and covering the lower surface of the current collector facing the electrode body. The gasket has an inner peripheral wall portion that covers the inner peripheral surface of the periphery forming the opening of the current collector.

[0008] According to the cylindrical battery disclosed herein, the sealing body and the current collector are welded in good condition. Attached Figure Description

[0009] Figure 1 This is a cross-sectional view of a cylindrical battery as an example of an implementation method.

[0010] Figure 2 yes Figure 1 Enlarged view of part A in the image.

[0011] Figure 3 This diagram illustrates the process of injecting electrolyte into an outer can of a cylindrical battery, as an example of an implementation (illustrations of the positive electrode lead and insulating plate are omitted).

[0012] Figure 4 This is a diagram showing a modified example of a washer. Detailed Implementation

[0013] Hereinafter, with reference to the accompanying drawings, an example of an embodiment of the cylindrical battery involved in this disclosure will be described in detail. It should be noted that structures formed by selectively combining the structural elements of the various embodiments and modifications described below are included within the scope of this disclosure.

[0014] Figure 1 This is a cross-sectional view of a cylindrical battery 1 as an example of an implementation. Figure 1 As shown, the cylindrical battery 1 includes: an electrode body 10; a bottomed cylindrical outer can 20 containing the electrode body 10 and electrolyte; and a sealing body 30 that seals the opening of the outer can 20. The electrode body 10 includes a positive electrode, a negative electrode, and a spacer, and has a spiral winding structure in which the positive and negative electrodes are wound together in a spiral shape with the spacer separating them. The electrolyte may be an aqueous electrolyte, but in this embodiment, a non-aqueous electrolyte is used. The outer can 20 has a slotted portion 23 formed in the side wall 21, and the sealing body 30 is supported by the slotted portion 23 to seal the opening of the outer can 20. Hereinafter, for ease of explanation, the sealing body 30 side of the cylindrical battery 1 will be described as upper, and the bottom 22 side of the outer can 20 as lower.

[0015] The cylindrical battery 1 further includes: an annular current-collecting member, i.e., a positive current-collecting plate 40, which connects the positive electrode lead 11 and is welded to the sealing body 30; and a gasket 50 disposed between the outer can 20 and the sealing body 30, covering the lower surface of the positive current-collecting plate 40 facing the electrode body 10. Additionally, the cylindrical battery 1 includes the electrode body 10 and an insulating plate 60 disposed between the slotted portion 23 and the positive current-collecting plate 40. The insulating plate 60 prevents the positive electrode and the positive electrode lead 11 from contacting the outer can 20, and also prevents the positive electrode lead 11 from contacting the negative electrode of the electrode body 10. The cylindrical battery 1 may also have a lower insulating plate disposed between the electrode body 10 and the can bottom 22.

[0016] Although described in detail later, the gasket 50 has an inner peripheral wall portion 52 that covers the inner peripheral surface of the periphery of the opening 43 forming the positive electrode current collector 40. The cylindrical battery 1 is manufactured by accommodating the electrode body 10 and the positive electrode current collector 40 inside the outer casing 20 and injecting electrolyte, then welding the sealing body 30 to the positive electrode current collector 40. However, the gasket 50 with the inner peripheral wall portion 52 prevents the electrolyte from contacting the positive electrode current collector 40. In the manufacturing process of the cylindrical battery 1, the electrolyte is injected so that it does not exceed the upper end of the inner peripheral wall portion 52. In this embodiment, the positive electrode current collector 40 connected to the positive electrode lead 11 is exemplified as a current collector member, but it is also possible to provide a negative electrode current collector member connected to the negative electrode lead.

[0017] As described above, the electrode body 10 has a spiral structure in which the positive and negative electrodes are wound together in a spiral shape with spacers between them. The positive electrode, negative electrode, and spacers are all strip-shaped bodies, alternately stacked in the radial direction of the electrode body 10 by being wound into a spiral. The negative electrode is formed with a dimension one turn larger than the positive electrode to prevent lithium deposition. That is, the negative electrode is formed to be longer than the positive electrode in both the long side direction and the width direction (short side direction). The spacers are formed with a dimension at least one turn larger than the positive electrode, for example, two spacers are arranged to clamp the positive electrode.

[0018] The electrode body 10 has a positive lead 11 that is connected to the positive electrode by welding or the like, and a negative lead that is connected to the negative electrode by welding or the like. The positive lead 11 electrically connects the positive electrode to the sealing body 30 via the positive current collector 40. The positive lead 11 extends and protrudes from the upper end of the electrode body 10, passes through the insulating plate 60, the gasket 50, and each opening of the positive current collector 40, and is welded to the upper surface of the positive current collector 40 facing the sealing body 30. The negative lead electrically connects the negative electrode to the outer can 20. Therefore, the sealing body 30 functions as an external terminal for the positive electrode, and the outer can 20 functions as an external terminal for the negative electrode.

[0019] The positive electrode has a positive electrode core and a positive electrode hybrid layer disposed on the positive electrode core. The positive electrode core can be made of a foil of a metal that is stable within the potential range of the positive electrode, such as aluminum, aluminum alloy, stainless steel, or titanium, or a film on the surface of such a metal. The positive electrode hybrid layer contains a positive electrode active material, a conductive agent, and a binder, and is preferably disposed on both sides of the positive electrode core where the portion connecting the positive electrode lead 11 is removed. The positive electrode active material is a lithium transition metal composite oxide containing transition metal elements such as Ni, Co, and Mn.

[0020] The positive electrode lead 11 is a rectangular conductive component, for example, made of a metal with aluminum as the main component. In this embodiment, multiple positive electrode leads 11 are connected to the positive electrode. One end of each positive electrode lead 11 is welded to the positive electrode along its long side, and the other end is welded to the positive electrode current collector plate 40 along its long side. The cylindrical battery 1 has a simple current collection structure in which the positive electrode and the positive electrode current collector plate 40 are directly connected through the positive electrode leads 11, resulting in excellent output characteristics. In the absence of a positive electrode mixing layer on the positive electrode core, multiple exposed portions of the positive electrode core are spaced apart along the long side of the positive electrode. The positive electrode leads 11 are connected one by one to each exposed portion by welding or the like.

[0021] The spacing between the exposed portions of the positive electrode lead 11 can be fixed or varied. For example, the layout of the positive electrode lead 11 can be appropriately set according to the battery performance, such as the capacity and output characteristics of the cylindrical battery 1. Therefore, the spacing between the exposed portions of each core is determined according to this layout. It should be noted that the number of cylindrical battery 1 can be one, but in large batteries, multiple numbers are preferred. For example, there can be 3 or more but less than 15, or 6 or more but less than 10.

[0022] The negative electrode has a negative electrode core and a negative electrode mixing layer disposed on the negative electrode core. The negative electrode core can be a foil of a metal stable within the negative electrode potential range, such as copper, copper alloy, stainless steel, nickel, or nickel alloy, or a film of such metal disposed on its surface. The negative electrode mixing layer contains a negative electrode active material and a binder, and is preferably disposed on both sides of the negative electrode core where the portion connecting the negative electrode lead has been removed. The negative electrode active material is generally a carbon material that reversibly absorbs and releases lithium ions. The negative electrode active material can also be an element alloyed with Li, such as Si or Sn, or a material containing such an element. It should be noted that the negative electrode core and the outer packaging can 20 can also be electrically connected without the negative electrode lead.

[0023] The spacer uses a porous sheet material that is both ion-permeable and insulating. Specific examples of porous sheets include microporous films, woven fabrics, and nonwoven fabrics. Preferred materials for the spacer include polyolefins such as polyethylene and polypropylene, and cellulose. The spacer can be a single-layer or multi-layer structure. For example, the spacer may have a multi-layer structure comprising a thermoplastic resin layer such as a polyolefin and a cellulose fiber layer, a two-layer structure of polyethylene (PE) / polypropylene (PP), or a three-layer structure of PE / PP / PE.

[0024] The non-aqueous electrolyte contained in the outer container 20 includes a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. The non-aqueous solvent may include, for example, esters, ethers, nitriles, amides, and mixtures of two or more of these solvents. The non-aqueous solvent may also contain halogen-substituted derivatives in which at least a portion of the hydrogen atoms of these solvents have been replaced by halogen atoms such as fluorine. Examples of non-aqueous solvents include ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), and mixtures thereof. The electrolyte salt may be, for example, a lithium salt such as LiPF6.

[0025] The outer can 20 is a bottomed cylindrical metal container with an opening at one axial end (top end). It has cylindrical sidewalls 21 and a round bottom 22 when viewed from below. Generally, the outer can 20 is made of a metal with iron as the main component, but it can also be made of a metal with aluminum or the like as the main component. Furthermore, the outer can 20 has a slot 23 formed along the circumferential direction of the sidewalls 21. The slot 23 is formed near the opening of the outer can 20 at a position a given length away from the top end of the outer can 20. The given length is, for example, a length that is more than 1% and less than 20% of the axial length of the outer can 20.

[0026] In this embodiment, a safety valve mechanism that operates in the event of an abnormality in the cylindrical battery 1 is provided at the bottom 22 of the outer can 20. Additionally, the safety valve mechanism is provided in the sealing body 30. A thin-walled portion is formed at the bottom 22, for example. If an abnormality occurs in the cylindrical battery 1 and the internal pressure rises, this thin-walled portion breaks first, forming a gas outlet at the bottom 22.

[0027] The slotted portion 23 is a part of the sidewall 21 that extends inward toward the outer can 20, for example, formed by spinning the sidewall 21 from the outside. It should be noted that at the location where the slotted portion 23 is formed, the outer can 20 has a reduced diameter, forming a fine-line groove on the outer circumferential surface of the sidewall 21. Preferably, the slotted portion 23 has a roughly U-shaped cross-section and is annular along the entire circumferential length of the sidewall 21. The slotted portion 23 is formed by machining the sidewall 21 after the electrode body 10 is housed inside the outer can 20.

[0028] The sealing body 30 is a metal component with a circular plate shape. The sealing body 30 has a shape that protrudes radially outward from the center of the cylindrical battery 1. When the cylindrical battery 1 is modularized to form a battery pack, wiring material is connected to the sealing body 30. Therefore, the sealing body 30 functions as the positive external terminal of the cylindrical battery 1 and is also referred to as the external terminal or top cover. The sealing body 30 is disposed on the slotted portion 23 of the outer can 20 via a gasket 50 and is fixed to the upper end of the outer can 20. The upper end of the outer can 20 is bent inward and pressed against the sealing body 30.

[0029] The positive current collector 40 is a metal component with the same diameter as the sealing body 30, and is positioned closer to the electrode body 10 than the sealing body 30. The positive current collector 40 has an opening 43 at its radial center, thus forming an annular shape. Positive lead 11 is welded to the inner circumferential portion of the positive current collector 40, and the sealing body 30 is welded to its outer circumferential portion. Although described in detail later, for the positive current collector 40, the positive lead 11 is welded before the electrolyte is injected into the outer packaging tank 20, and the sealing body 30 is welded after the electrolyte is injected.

[0030] Gasket 50 is a resin component used to prevent contact between the outer can 20, the sealing body 30, and the positive current collector 40, and to ensure insulation between the positive and negative electrodes. Gasket 50 is located between the outer can 20, the sealing body 30, and the positive current collector 40, and covers the lower surface and inner circumferential surface of the positive current collector 40. In addition, gasket 50 seals the gap between the outer can 20 and the sealing body 30 to seal the interior of the cylindrical battery 1. Gasket 50 has an opening 51 at its radial center that overlaps vertically with the opening 43 of the positive current collector 40, thus forming an annular shape.

[0031] The following is for reference Figure 2 The structure of the positive current collector 40 and the gasket 50 is described in detail. Figure 2 yes Figure 1 Enlarged view of part A in the image.

[0032] like Figure 2 As shown, the positive current collector 40 is bent toward the sealing body 30 at a position radially outward from the periphery of the opening 43. The positive current collector 40 includes: a first region 41 disposed radially outward from the bent portion; and a second region 42 disposed radially inward from the bent portion and one level lower than the first region 41. The first region 41 contacts the sealing body 30, and a portion of the first region 41 is welded to the sealing body 30. The upper surface of the second region 42 is disposed closer to the electrode body 10 than the upper surface of the first region 41, and a gap exists between the second region 42 and the sealing body 30. The first region 41 and the second region 42 are, for example, formed in an annular shape with a fixed width along the circumferential direction and formed radially flat.

[0033] The positive current collector 40 is a conductive member having an opening 43 and an annular step that forms the boundary between the first region 41 and the second region 42. The thickness of the positive current collector 40 is, for example, 0.3 mm or more and 1.0 mm or less, or 0.4 mm or more and 0.8 mm or less, and is substantially fixed throughout the first region 41 and the second region 42. The step of the positive current collector 40 may also be greater than the thickness of the current collector. The height difference between the upper surfaces of the first region 41 and the second region 42 (the height of the step) is, for example, 0.8 mm or more and 1.5 mm or less.

[0034] The opening 43 of the positive current collector plate 40 is a through hole for the positive lead 11 and electrolyte to pass through. The opening 43 is formed, for example, in a roughly circular shape when viewed from above, but its shape is not particularly limited. Multiple positive leads 11 pass through the openings 43 and 51 of the positive current collector plate 40 and the gasket 50 and are wound towards the upper surface of the positive current collector plate 40, and are welded to the upper surface of the second region 42. The welded portion formed in the first region 41 with the sealing body 30 can be formed continuously in a ring shape, for example, or multiple portions can be formed intermittently on the same circumference.

[0035] The inner peripheral surface 44 of the positive current collector plate 40 forming the periphery of the opening 43 is, for example, a surface along the thickness direction (vertical direction) of the current collector plate, but it can also be gently curved or tilted relative to the vertical direction. In this embodiment, the inner peripheral surface 44 is set to be a surface that is approximately perpendicular to the top and bottom surfaces of the positive current collector plate 40. It should be noted that the height (length along the vertical direction) of the inner peripheral surface 44 corresponds to the thickness of the second region 42.

[0036] In the cylindrical battery 1, the lower surface and inner circumferential surface 44 of the positive electrode current collector 40 are covered by a gasket 50. In the manufacturing process of the cylindrical battery 1, as described above, after the electrode body 10 and the positive electrode current collector 40 are housed in the outer packaging can 20, an electrolyte is injected. If the electrolyte comes into contact with the positive electrode current collector 40, it will climb up to the first region 41, which serves as the welding part to the sealing body 30, due to capillary action, resulting in welding defects. However, by covering the lower surface and inner circumferential surface 44 of the positive electrode current collector 40 with the gasket 50, the current collector is prevented from being wetted by the electrolyte. As a result, welding defects between the sealing body 30 and the positive electrode current collector 40 caused by the electrolyte can be prevented.

[0037] A portion of the washer 50 is inserted into the opening 43 from below, thereby covering the inner peripheral surface 44. The washer 50 has an opening 51 for the passage of the positive electrode lead 11 and electrolyte, and an inner peripheral wall portion 52 that covers the inner peripheral surface 44 of the positive electrode current collector 40. The inner peripheral wall portion 52 is a wall erected at the periphery of the opening 51 to prevent the positive electrode current collector 40 from being wetted by the electrolyte. In the electrolyte injection process, for example, the electrolyte is injected up to a height exceeding the lower surface of the positive electrode current collector 40. At this time, it is preferable to inject the electrolyte so that it does not exceed the upper end of the inner peripheral wall portion 52 (see below). Figure 3 ).

[0038] The washer 50 completely covers the lower surface of the positive current collector 40. The washer 50 does not have an opening that exposes the lower surface of the positive current collector 40. The opening formed in the washer 50 is only the radially central opening 51, and there is no gap on the lower surface of the washer 50 in the direction towards the electrode body 10 for electrolyte immersion. In this embodiment, a curved portion is also formed on the lower surface of the washer 50, corresponding to the curved portion formed on the positive current collector 40. The curved portion of the washer 50 bends in the thickness direction, thereby forming a step on the lower surface of the washer 50.

[0039] The outer peripheral end of the gasket 50 is wound around the upper surface of the sealing body 30 and pressed from above through the upper end of the compressed outer can 20. The gasket 50 covers the outer peripheral surface and lower surface of the sealing body 30 and the positive current collector plate 40 from the peripheral portion of the upper surface of the sealing body 30, and is installed throughout the inner peripheral surface 44 of the positive current collector plate 40.

[0040] The gasket 50 is made of a resin material with excellent chemical resistance (electrolyte resistance). A preferred material for the gasket 50 is polypropylene. The thickness of the gasket 50 is not particularly limited, but it is, for example, 0.3 mm or more and 1.0 mm or less in the portion covering the lower surface of the positive current collector 40 and the inner peripheral wall portion 52.

[0041] The inner peripheral wall portion 52 is formed in an annular shape along the inner peripheral surface 44 of the positive electrode current collector 40. In other words, the inner peripheral wall portion 52 is formed in an annular shape along the periphery of the opening portion 51. The inner peripheral wall portion 52 is, for example, a vertical wall formed perpendicularly to the upper surface of the washer 50, which is opposite to the lower surface of the positive electrode current collector 40. Although the height H1 of the inner peripheral wall portion 52 can vary along the circumferential direction, it is fixed along the circumferential direction in this embodiment. It should be noted that the height H1 of the inner peripheral wall portion 52 means the length along the vertical direction from the upper surface of the washer 50 to the upper end of the inner peripheral wall portion 52.

[0042] The inner peripheral wall portion 52 preferably covers more than 50% of the height of the inner peripheral surface 44 of the positive current collector 40, and is formed at a height not exceeding the upper end of the inner peripheral surface 44. By lowering the upper end position of the inner peripheral wall portion 52 relative to the upper surface of the second region 42 of the positive current collector 40, soldering of the positive lead 11 relative to the upper surface of the second region 42 becomes easier. Figure 2 In the example shown, although the upper surface of the washer 50 is in contact with the lower surface of the positive current collector 40, a small gap may exist between these two surfaces. When a gap exists between the upper surface of the washer 50 and the lower surface of the second region 42 of the positive current collector 40, it is preferable that the inner peripheral wall portion 52 be at least 50% of the height of the inner peripheral surface 44 plus the height corresponding to the gap.

[0043] The inner peripheral wall portion 52 is formed relatively high within a range not exceeding the upper end of the inner peripheral surface 44. The inner peripheral wall portion 52 is formed to a height that covers, for example, 60%, 70%, or 80% or more of the height of the inner peripheral surface 44. When the upper surface of the washer 50 contacts the lower surface of the second region 42 of the positive current collector plate 40, it is preferable that the height H1 of the inner peripheral wall portion 52 is 50% or more of the height of the inner peripheral surface 44, but it can also be 60%, 70%, or 80% or more. It should be noted that the height of the inner peripheral surface 44 is the same as the thickness of the second region 42; therefore, in other words, it is preferable that the height H1 of the inner peripheral wall portion 52 is 50% or more of the thickness of the second region 42.

[0044] The inner peripheral wall portion 52 can also be formed in a ring shape along the inner peripheral surface 44 of the positive electrode current collector 40, covering substantially the entire area of ​​the inner peripheral surface 44. Figure 2 In the example shown, the upper surface of the second region 42 of the positive current collector 40 is flush with the upper end face of the inner peripheral wall portion 52, forming an annular inner peripheral wall portion 52 that covers the entire area of ​​the inner peripheral surface 44. The positive current collector 40 is disposed on the slotted portion 23 of the outer can 20, for example, in a state where it is assembled to the gasket 50. The inner peripheral wall portion 52 may also be joined to the inner peripheral surface 44 of the positive current collector 40.

[0045] The following is for reference Figure 3 The manufacturing method of cylindrical battery 1 will be explained. Figure 3 This diagram illustrates the electrolyte injection process. For clarity, the positive lead 11 and the insulating plate 60 are omitted from the diagram.

[0046] Cylindrical battery 1, for example, is manufactured through the following process.

[0047] (1) The electrode body 10 and the insulating plate 60 are housed in the outer packaging container 20. For example, if insulation can be ensured by the spacers that constitute the electrode body 10 alone, the insulating plate 60 may be omitted.

[0048] (2) A slotted portion 23 is formed on the side wall 21 of the outer can 20, and a gasket 50 and a positive current collector 40 are disposed on the slotted portion 23. Alternatively, the positive current collector 40 and the gasket 50 can be pre-assembled and then disposed on the slotted portion 23.

[0049] (3) The electrolyte is injected into the outer container 20 containing the electrode body 10, the positive electrode current collector 40 and the gasket 50. The electrolyte is absorbed into the container through the openings 43 and 51 of the positive electrode current collector 40 and the gasket 50 and is absorbed by the electrode body 10.

[0050] (4) A sealing body 30 is disposed on the positive current collector plate 40 and the sealing body 30 is welded to the first region 41 of the positive current collector plate 40. The sealing body 30 is preferably laser welded and laser is irradiated from the upper surface of the sealing body 30.

[0051] (5) Bend the upper end of the outer can 20 inward to press and fix the sealing body 30. The pressing and fixing of the sealing body 30 can also be carried out before welding the sealing body 30 relative to the positive current collector 40.

[0052] like Figure 3 As shown, in the above-described process (2), the lower surface and inner circumferential surface 44 of the positive current collector plate 40 are covered by gaskets 50. Furthermore, before injecting the electrolyte 70, the positive lead 11 is soldered to the upper surface of the second region 42 of the positive current collector plate 40. The soldering of the positive lead 11 can be performed, for example, by ultrasonic welding.

[0053] like Figure 3 As shown, in the above-described step (3), electrolyte 70 is injected until it exceeds the height of the lower surface of the positive current collector 40. On the other hand, the level of electrolyte 70 is controlled so that it does not exceed the upper end of the inner peripheral wall portion 52 of the gasket 50. In this case, since the inner peripheral surface 44 of the positive current collector 40 is covered by the inner peripheral wall portion 52, electrolyte 70 will not adhere to the inner peripheral surface 44. Furthermore, the lower surface of the positive current collector 40 is also covered by the gasket 50, so electrolyte will not seep between the positive current collector 40 and the gasket 50.

[0054] When the inner circumferential surface of the positive electrode current collector is exposed without being covered by the gasket, due to capillary action, the electrolyte rises to the welding area with the sealing body, i.e., the first region, and laser welding occurs in the presence of the electrolyte. In this case, due to the influence of the vaporized electrolyte, welding defects may occur. In contrast, in Figure 3 In the illustrated manner, the positive current collector 40 is covered by a gasket 50, and the electrolyte 70 is not attached to the positive current collector 40. Therefore, welding can be performed in the absence of electrolyte, and a good welding condition can be achieved.

[0055] It should be noted that the above embodiments can be appropriately modified within the scope of the purpose of this disclosure. For example, such as Figure 4 As shown, the inner peripheral wall portion 52 of the washer 50 can also extend beyond the upper end of the inner peripheral surface 44 of the positive current collector 40 and wrap around the upper surface of the positive current collector 40.

[0056] exist Figure 4 In the example shown, the inner peripheral wall portion 52 formed on the inner periphery of the gasket 50 is formed in a ring shape along the inner peripheral surface 44 of the positive electrode current collector 40, and covers the entire area of ​​the inner peripheral surface 44 from the lower end to the upper end, and wraps around the upper surface of the second region 42, covering the upper surface of the second region 42 located at the periphery of the opening 43. In this case, the adhesion of electrolyte to the positive electrode current collector 40 can be prevented more reliably. In addition, since the inner peripheral wall portion 52 protrudes upward more than the upper surface of the second region 42, the portion of the positive electrode lead 11 that overlaps with the inner peripheral wall portion 52 is bent to become convex upward.

[0057] -Symbol Explanation-

[0058] 1 Cylindrical battery, 10 Electrode body, 11 Positive lead, 11 Outer can, 21 Side wall, 22 Can bottom, 23 Slotted part, 30 Sealing body, 40 Positive current collector plate, 41 First region, 42 Second region, 43 Opening, 44 Inner circumferential surface, 50 Gasket, 51 Opening, 52 Inner circumferential wall, 60 Insulating plate.

Claims

1. A cylindrical battery comprising: an electrode body; a bottomed cylindrical outer can containing the electrode body and an electrolyte; and a sealing body sealing the opening of the outer can, the cylindrical battery including leads connected to electrodes constituting the electrode body. The cylindrical battery also features: A current collector, in the form of a ring, connects to the lead wire and is welded to the sealing body; and A gasket is disposed between the outer can and the sealing body, and covers the lower surface of the current collector facing the electrode body. The washer has an inner peripheral wall portion that covers the inner peripheral surface of the periphery of the opening formed by the current collector.

2. The cylindrical battery according to claim 1, wherein, The inner peripheral wall portion is formed in a ring shape along the inner peripheral surface of the current collector.

3. The cylindrical battery according to claim 1 or 2, wherein, The inner peripheral wall portion covers more than 50% of the height of the inner peripheral surface of the current collector, and is formed at a height that does not exceed the upper end of the current collector.

4. The cylindrical battery according to claim 3, wherein, The inner peripheral wall portion is formed in a ring shape along the inner peripheral surface of the current collector, substantially covering the entire inner peripheral surface of the current collector.

5. The cylindrical battery according to claim 1 or 2, wherein, The inner peripheral wall portion extends beyond the upper end of the inner peripheral surface and wraps around the upper surface of the current collector.

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