Cylindrical battery

Abstract

A cylindrical battery (10) comprises an electrode body (14), an electrolyte, a bottomed cylindrical outer can (16) that accommodates the electrode body (14) and the electrolyte, and a sealing body (17) that closes off an opening of the outer can (16). The cylindrical battery (10) has a structure in which a grooved portion (22) for supporting the sealing body (17) is formed in the outer can (16), and a negative electrode lead (21) extending from a negative electrode (12) constituting the electrode body (14) is connected to the outer can (16). The cylindrical battery (10) further comprises: an upper insulating plate (18) that is positioned between the electrode body (14) and the sealing body (17); and a porous body (30) that is positioned radially outward of the upper insulating plate (18) at least relative to the peripheral edge of the upper insulating plate (18), the porous body (30) being disposed between the electrode body (14) and the grooved portion (22).

Description

Cylindrical battery

[0001] The present disclosure relates to a cylindrical battery, and more specifically to a cylindrical battery provided with an upper insulating plate.

[0002] Conventionally, a cylindrical battery is widely known that includes a bottomed cylindrical outer can that accommodates an electrode body and an electrolytic solution, a sealing body that closes an opening of the outer can, an upper insulating plate disposed between the electrode body and the sealing body, and a grooved portion that supports the sealing body formed in the outer can (see, for example, Patent Document 1). Generally, a lead extending from a positive electrode or a negative electrode of the electrode body is connected to the outer can having the grooved portion formed thereon, and the outer can functions as an external terminal for the positive electrode or the negative electrode. For this reason, it is necessary to dispose the upper insulating plate between the electrode body and the grooved portion to prevent a short circuit therebetween. In the manufacturing process of a cylindrical battery, after the electrode body and the upper insulating plate are accommodated in the outer can, the electrolytic solution is injected into the outer can.

[0003] Japanese Patent Application Publication No. 2020-149821

[0004] In order to more reliably prevent a short circuit between the electrode body and the grooved portion of the outer can, it is necessary to increase the diameter of the upper insulating plate to approximate the inner diameter of the outer can. On the other hand, when the gap between the peripheral edge of the upper insulating plate and the inner surface of the outer can becomes small, it becomes difficult to smoothly inject the electrolytic solution into the outer can.

[0005] A cylindrical battery according to the present disclosure includes an electrode body, an electrolytic solution, a bottomed cylindrical outer can that accommodates the electrode body and the electrolytic solution, and a sealing body that closes an opening of the outer can, wherein a grooved portion that supports the sealing body is formed in the outer can, and a lead extending from a positive electrode or a negative electrode constituting the electrode body is connected to the outer can, the cylindrical battery further comprising: an upper insulating plate disposed between the electrode body and the sealing body; and an insulating porous body disposed at least radially outward of the insulating plate from the peripheral edge of the upper insulating plate, and interposed between the electrode body and the grooved portion of the outer can.

[0006] According to the cylindrical battery of the present disclosure, it is possible to smoothly inject the electrolytic solution into the outer can while more reliably preventing a short circuit between the electrode body and the grooved portion of the outer can.

[0007] This is a cross-sectional view of a cylindrical battery, which is an example of an embodiment. This is a plan view of the upper insulating plate and porous body. This is a diagram showing a first modified example of a cylindrical battery, which is an example of an embodiment. This is a diagram showing a second modified example of a cylindrical battery, which is an example of an embodiment.

[0008] Hereinafter, an example of an embodiment of the cylindrical battery according to this disclosure will be described in detail with reference to the drawings. Note that the cylindrical battery according to this disclosure is not limited to the embodiments described below. Furthermore, forms obtained by selectively combining the various components of the multiple embodiments and modifications described below are also included in this disclosure.

[0009] Figure 1 is a schematic diagram showing an axial cross-section including the central axis of a cylindrical battery 10, which is an example of an embodiment. As shown in Figure 1, the cylindrical battery 10 comprises an electrode body 14, an electrolyte, a bottomed cylindrical outer container 16 that houses the electrode body 14 and the electrolyte, and a sealing body 17 that closes the opening of the outer container 16. The outer container 16 has grooves 22 formed on its side surface, and the sealing body 17 is supported by the grooves 22 and closes the opening of the outer container 16. In the following, for convenience of explanation, the side of the cylindrical battery 10 with the sealing body 17 will be considered the top, and the bottom side of the outer container 16 will be considered the bottom. The outer container 16 is a bottomed cylindrical metal container with one axial end (upper end) open, and the upper end opening of the outer container 16 is closed by the sealing body 17.

[0010] The electrolyte may be an aqueous electrolyte, but in this embodiment, a non-aqueous electrolyte is used. The non-aqueous electrolyte has, for example, lithium-ion conductivity. The cylindrical battery 10 is a non-aqueous electrolyte secondary battery, and among these, a lithium-ion battery is preferred.

[0011] A non-aqueous electrolyte comprises a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. Examples of non-aqueous solvents include esters, ethers, nitriles, amides, and mixtures of two or more of these. Examples of non-aqueous solvents include ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and mixtures thereof. The non-aqueous solvent may also contain halogen-substituted solvents (e.g., fluoroethylene carbonate) in which at least some of the hydrogen atoms of the solvent are replaced with halogen atoms such as fluorine. Examples of electrolyte salts include LiPF4. ６ Lithium salts such as these are used.

[0012] The electrode body 14 includes a positive electrode 11, a negative electrode 12, and a separator 13, and has a wound structure in which the positive electrode 11 and the negative electrode 12 are wound in a spiral shape via the separator 13. The cylindrical battery 10 has a structure in which a lead extending from the negative electrode 12 constituting the electrode body 14 is connected to the outer casing 16. In this embodiment, the negative electrode lead 21 extending from the negative electrode 12 is connected to the outer casing 16, and the outer casing 16 becomes the negative electrode terminal. As will be described in detail later, the grooved portion 22 formed in the outer casing 16 becomes part of the negative electrode terminal, so it is necessary to insulate the positive electrode 11 constituting the electrode body 14 from the grooved portion 22 so that they do not short-circuit.

[0013] The positive electrode 11, the negative electrode 12, and the separator 13 are all elongated strip-shaped bodies that are alternately stacked in the radial direction of the electrode body 14 by being wound in a spiral shape. The negative electrode 12 is formed to be slightly larger than the positive electrode 11 in order to prevent lithium deposition. That is, the negative electrode 12 is formed to be longer in both the length and width directions than the positive electrode 11. The separator 13 is formed to be at least slightly larger than the positive electrode 11, and two of them are arranged, for example, so as to sandwich the positive electrode 11. The electrode body 14 has a positive electrode lead 20 connected to the positive electrode 11 by welding or the like, and a negative electrode lead 21 connected to the negative electrode 12 by welding or the like.

[0014] The positive electrode 11 comprises a positive electrode core and a positive electrode mixture layer provided on the positive electrode core. The positive electrode core can be made of a metal foil that is stable within the potential range of the positive electrode 11, such as aluminum, aluminum alloy, stainless steel, or titanium, or a film with the metal arranged on its surface. The positive electrode mixture layer contains a positive electrode active material, a conductive agent, and a binder, and is preferably provided on both sides of the positive electrode core, excluding the portion to which the positive electrode lead 20 is connected. The positive electrode active material is a lithium transition metal composite oxide containing transition metal elements such as Ni, Co, and Mn.

[0015] The negative electrode 12 comprises a negative electrode core and a negative electrode mixture layer provided on the negative electrode core. The negative electrode core can be made of a metal foil that is stable within the potential range of the negative electrode 12, such as copper, copper alloy, stainless steel, nickel, or nickel alloy, or a film with the metal arranged on its surface. The negative electrode mixture layer contains a negative electrode active material and a binder, and is preferably provided on both sides of the negative electrode core except for the portion to which the negative electrode lead 21 is connected. Generally, a carbon material that reversibly intercepts and releases lithium ions is used as the negative electrode active material. The negative electrode active material may also be an element that alloys with Li, such as Si or Sn, or a material containing such an element.

[0016] The separator 13 is made of a porous sheet having ion permeability and insulating properties. Specific examples of porous sheets include microporous thin films, woven fabrics, and nonwoven fabrics. Suitable materials for the separator 13 include polyethylene, polyolefins such as polypropylene, and cellulose. The separator 13 may have a single-layer structure or a multi-layer structure. For example, the separator 13 may have a multi-layer structure including a thermoplastic resin layer such as polyolefin and a cellulose fiber layer, a two-layer structure of polyethylene (PE) / polypropylene (PP), or a three-layer structure of PE / PP / PE.

[0017] The cylindrical battery 10 includes an upper insulating plate 18 positioned between the electrode body 14 and the sealing body 17. The cylindrical battery 10 also includes a lower insulating plate 19 positioned between the electrode body 14 and the inner surface of the bottom of the outer casing 16. In other words, insulating plates are positioned above and below the electrode body 14. The cylindrical battery 10 further includes an insulating porous body 30 positioned radially outward from the periphery of the upper insulating plate 18. As will be described in more detail later, the porous body 30 more reliably prevents short circuits between the electrode body 14 and the grooved portion 22 of the outer casing 16, while enabling smooth injection of electrolyte into the outer casing 16.

[0018] In this embodiment, the positive lead 20 extends through the opening 18b of the upper insulating plate 18 towards the sealing body 17, and the negative lead 21 extends through the outside of the lower insulating plate 19 towards the bottom of the outer can 16. The positive lead 20 is connected to the lower surface of the internal terminal plate 23 of the sealing body 17 by welding or the like, and the cap 27, which is the top plate of the sealing body 17 and is electrically connected to the internal terminal plate 23, becomes the positive terminal. The negative lead 21 is connected to the inner bottom surface of the outer can 16 by welding or the like, as described above, and the outer can 16 becomes the negative terminal.

[0019] A gasket 28 is provided between the outer casing 16 and the sealing body 17 to ensure airtightness inside the battery. The gasket 28 further insulates the outer casing 16 and the sealing body 17 from each other. As described above, a grooved portion 22 is formed in the outer casing 16. The grooved portion 22 is a part of the side surface of the outer casing 16 that protrudes inward and supports the sealing body 17 via the gasket 28. The grooved portion 22 is formed in an annular shape along the circumferential direction of the outer casing 16 and supports the sealing body 17 on its upper surface. The sealing body 17 is fixed to the upper part of the outer casing 16 by the grooved portion 22 and the open end of the outer casing 16 that is crimped to the sealing body 17.

[0020] The grooved portion 22 is formed, for example, by spinning the side surface of the outer can 16 after housing the electrode body 14, upper insulating plate 18, lower insulating plate 19, and porous body 30 inside the outer can 16. The grooved portion 22 protrudes radially inward from the outer can 16 above the outer circumference of the electrode body 14 and faces the outer circumference of the electrode body 14 in the axial direction of the outer can 16. In this embodiment, since the outer can 16 functions as a negative electrode terminal, it is necessary to prevent short circuits between the grooved portion 22 and the positive electrode 11 of the electrode body 14. The protruding length of the grooved portion 22 (the length along the radial direction from the inner surface of the outer can 16 at the base of the grooved portion 22 to the tip) is, for example, 1.0 mm or more and 3.0 mm or less.

[0021] The sealing body 17 has a structure in which an internal terminal plate 23, a lower valve body 24, an insulating member 25, an upper valve body 26, and a cap 27 are stacked in order from the electrode body 14 side. Each component constituting the sealing body 17 has, for example, a disc shape or a ring shape, and each component except the insulating member 25 is electrically connected to one another. The lower valve body 24 and the upper valve body 26 are connected at their respective centers, with the insulating member 25 interposed between their respective peripheries. When the internal pressure of the battery rises due to abnormal heat generation, the lower valve body 24 deforms and ruptures, pushing the upper valve body 26 towards the cap 27, thereby interrupting the current path between the lower valve body 24 and the upper valve body 26. If the internal pressure rises further, the upper valve body 26 ruptures, and gas is discharged from the opening of the cap 27.

[0022] The electrode body 14 has a hollow portion 14z extending in the axial direction of the electrode body 14 at and near the winding center. The hollow portion 14z serves as a gas discharge path when a malfunction occurs in the battery, and is also used as an insertion point for the welding rod when welding the negative electrode lead 21 to the inner surface of the bottom of the can. The upper insulating plate 18 has an opening 18a formed at a position that overlaps the hollow portion 14z in the vertical direction so as not to obstruct the discharge of gas through the hollow portion 14z. The electrode body 14 is manufactured by winding the positive electrode 11 and the negative electrode 12 in a spiral shape with a separator 13 in between using a cylindrical winding core, and the hollow portion 14z is formed by removing the winding core after winding. It is also possible to leave the winding core in place. In either case, the hollow portion 14z is formed.

[0023] The configuration of the upper insulating plate 18 and the porous body 30 will be described in detail below with reference to Figures 1 and 2. Figure 2 is a plan view of the upper insulating plate 18 and the porous body 30.

[0024] As shown in Figures 1 and 2, the cylindrical battery 10 includes a porous body 30 interposed between the electrode body 14 and the grooved portion 22 of the outer casing 16. The porous body 30 is an insulator positioned radially outward from the periphery of the upper insulating plate 18, as described above. In this embodiment, the porous body 30 prevents short circuits between the positive electrode 11 of the electrode body 14 and the grooved portion 22. The porous body 30 has the same insulating properties as the separator 13 and the upper insulating plate 18.

[0025] The upper insulating plate 18 is preferably made of a rigid material and has high rigidity. On the other hand, the porous body 30 is preferably flexible. In this case, the effect of using the upper insulating plate 18 and the porous body 30 together becomes more pronounced. The upper insulating plate 18 functions as a fixing member that prevents short circuits between the negative electrode 12 of the electrode body 14 and the sealing body 17, and between the negative electrode 12 and the positive electrode lead 20, and also suppresses the movement of the electrode body 14. For this reason, it is preferable that the upper insulating plate 18 has high rigidity and does not bend easily. On the other hand, the porous body 30 protrudes radially outward from the upper insulating plate 18 and contacts the inner surface of the outer can 16. For this reason, it is preferable that the porous body 30 is flexible and easy to insert into the outer can 16.

[0026] Conventionally, from the viewpoint of improving insulation, the diameter of the upper insulating plate has been increased to bring it closer to the inner diameter of the outer casing. However, in this case, it becomes difficult to insert the upper insulating plate into the outer casing 16. Furthermore, the gap between the periphery of the upper insulating plate and the inner surface of the outer casing 16 becomes smaller, making it difficult to smoothly pour the electrolyte into the outer casing 16. With the cylindrical battery 10, by providing the porous body 30 radially outward from the periphery of the upper insulating plate 18, it is possible to more reliably prevent short circuits between the electrode body 14 and the grooved portion 22 while improving the pouring of the electrolyte.

[0027] Furthermore, since the porous body 30 requires high permeability of the electrolyte, it is difficult to give the porous body 30 the same rigidity as the upper insulating plate 18. In other words, it is difficult to use the porous body 30 alone as an insulating member in the upper part of the cylindrical battery 10. By using the upper insulating plate 18 and the porous body 30 in combination, it is possible to effectively perform the above functions while ensuring good mechanical strength and durability.

[0028] The upper insulating plate 18 may be made of a thermoplastic resin or a curable resin having a crosslinked structure. Examples of thermoplastic resins include polyolefins, polyamides, polyetheretherketones, and thermoplastic polyimides. Examples of curable resins include phenolic resins and epoxy resins. A suitable example of the upper insulating plate 18 is an insulating plate made of polypropylene. The upper insulating plate 18 may also contain reinforcing materials such as fibrous materials like glass fibers and carbon fibers, and fillers such as silica, clay, and mica.

[0029] The upper insulating plate 18 is formed in a substantially disc shape and broadly covers the upper surface of the electrode body 14. As described above, the upper insulating plate 18 prevents short circuits between the negative electrode 12 of the electrode body 14 and the sealing body 17, and between the negative electrode 12 and the positive electrode lead 20. The thickness of the upper insulating plate 18 is, for example, 100 μm or more and 400 μm or less, more preferably 200 μm or more and 300 μm or less. The diameter of the upper insulating plate 18 is smaller than the inner diameter of the portion located on the bottom side of the grooved portion 22 of the outer can 16, so that it can be easily inserted into the outer can 16. On the other hand, it is preferable that the diameter of the upper insulating plate 18 is larger than the inner diameter of the portion in which the grooved portion 22 is formed.

[0030] The peripheral edge of the upper insulating plate 18 is preferably interposed between the electrode body 14 and the grooved portion 22. The diameter of the upper insulating plate 18 is substantially constant around its entire circumference, larger than the inner diameter of the portion where the grooved portion 22 is formed, and smaller than the inner diameter of other portions. In this case, the upper insulating plate 18 can easily catch on the grooved portion 22 and hold down the electrode body 14, thereby more effectively suppressing the axial movement of the electrode body 14 in the outer can 16.

[0031] In this embodiment, the upper insulating plate 18 and the porous body 30 are arranged between the electrode body 14 and the grooved portion 22. However, since the porous body 30 is positioned radially outward from the periphery of the upper insulating plate 18, a gap is secured between the periphery of the upper insulating plate 18 and the inner surface of the outer container 16 for the electrolyte to pass through. The upper insulating plate 18 has a diameter such that, for example, when its center is positioned on the central axis of the outer container 16, it overlaps with the grooved portion 22 by a length of 50% to 80% of the protruding length of the grooved portion 22. In this case, the movement of the electrode body 14 can be effectively suppressed while ensuring smooth injection of the electrolyte on the outside of the upper insulating plate 18.

[0032] An opening 18a is formed in the center of the upper insulating plate 18. The upper insulating plate 18 further has openings 18b and 18c arranged to surround opening 18a. Openings 18a, 18b, and 18c are all formed to penetrate the upper insulating plate 18 in the thickness direction and serve as gas passages when a malfunction occurs in the battery. In addition, openings 18a, 18b, and 18c are through holes for the electrolyte to pass through, and opening 18b is for the positive electrode lead 20 to pass through. Opening 18a has a circular shape in plan view, and openings 18b and 18c have a roughly arc shape in plan view. In the example shown in Figure 2, one opening 18b and three openings 18c smaller than opening 18b are arranged on the same circumference, but the number and arrangement of openings 18b and 18c are not particularly limited.

[0033] As described above, the porous body 30 is positioned radially outward from the periphery of the upper insulating plate 18 and interposed between the electrode body 14 and the grooved portion 22. The porous body 30 has numerous through holes communicating in the thickness direction and is an insulator with excellent electrolyte permeability. By providing a gap between the inner circumferential surface of the outer can 16 and the periphery of the upper insulating plate 18, and positioning the porous body 30 to close this gap, it is possible to ensure smooth injection of the electrolyte on the outside of the upper insulating plate 18 while more reliably preventing short circuits between the electrode body 14 and the grooved portion 22. The thickness of the porous body 30 is, for example, 100 μm or more and 400 μm or less, more preferably 200 μm or more and 300 μm or less.

[0034] The porous body 30 surrounds the upper insulating plate 18 and is formed in an annular shape in plan view. The outer diameter and width (inner diameter) of the porous body 30 are substantially constant around its entire circumference. In the example shown in Figure 1, the upper insulating plate 18 and the porous body 30 are arranged on the same plane, and the porous body 30 is fitted onto the upper insulating plate 18. In this case, the total thickness can be reduced compared to the case where the upper insulating plate 18 and the porous body 30 are stacked in the thickness direction. The upper insulating plate 18 and the porous body 30 may be a single molded product, or they may be made of separate components and arranged separately inside the outer container 16. A single molded product of the upper insulating plate 18 and the porous body 30 can be manufactured, for example, by insert molding.

[0035] The porous body 30 only needs to have permeability and insulating properties for the electrolyte, but it is preferable that it is flexible and in contact with the inner surface of the outer can 16. That is, it is preferable that the porous body 30 is made of a flexible and deformable material and seals the gap between the periphery of the upper insulating plate 18 and the inner surface of the outer can 16. If the porous body 30 is flexible, it is possible to insert the porous body 30 into the outer can 16 even if the outer diameter of the porous body 30 is larger than the inner diameter of the outer can 16. The porous body 30 may also be elastically deformable.

[0036] The porous body 30 is composed of a porous material such as a woven fabric, a nonwoven fabric, or a polymer porous body, and may be composed of the same porous sheet as the separator 13. Woven fabrics and nonwoven fabrics are fibrous materials composed of natural fibers, chemical fibers, or a mixture thereof. Examples of natural fibers include plant fibers such as cotton and linen, and animal fibers such as wool and silk. Examples of chemical fibers include polyethylene fibers, polypropylene fibers, polyamide fibers, polyester fibers, and acrylic fibers. Examples of polymer porous bodies include foams such as polyurethane foam, polystyrene foam, polyethylene foam, and polypropylene foam.

[0037] The porous body 30 is preferably made of a fibrous material, and more preferably of a nonwoven fabric, from the viewpoint of electrolyte permeability and other factors. A nonwoven fabric is a sheet-like material manufactured by compressing fibers without weaving them, and felt is a type of nonwoven fabric. A preferred example of the nonwoven fabric constituting the porous body 30 is a polypropylene nonwoven fabric. Because the nonwoven fabric is flexible, it can be easily inserted into the outer container 16 and comes into contact with the inner surface of the outer container 16.

[0038] Hereinafter, modifications of the above embodiment will be described with reference to Figures 3 and 4. In the following, the differences from the above embodiment will be explained, and the same reference numerals will be used for components common to the above embodiment, and redundant explanations will be omitted.

[0039] As shown in Figures 3 and 4, the cylindrical batteries 10x and 10y are similar to the cylindrical battery 10 in that insulating porous bodies 30x and 30y are interposed between the electrode body 14 and the grooved portion 22 of the outer casing 16, radially outward from the periphery of the upper insulating plate 18. On the other hand, the cylindrical batteries 10x and 10y differ from the cylindrical battery 10 in that the porous bodies 30x and 30y are positioned between the upper insulating plate 18 and the electrode body 14. That is, a portion of the porous bodies 30x and 30y overlaps with the upper insulating plate 18 in the thickness direction, and the peripheral portions of the porous bodies 30x and 30y are positioned radially outward from the periphery of the upper insulating plate 18. Thus, it is sufficient that at least a portion of the porous bodies 30x and 30y are positioned radially outward from the periphery of the upper insulating plate 18.

[0040] As shown in Figure 3, the porous body 30x is formed in a ring shape, similar to the porous body 30. The porous body 30x overlaps the peripheral edge of the lower surface of the upper insulating plate 18 facing the electrode body 14, and protrudes outward from the peripheral edge of the upper insulating plate 18. In this case as well, it is preferable that the porous body 30x is flexible and in contact with the inner surface of the outer casing 16. It is also preferable that the porous body 30x is joined to the lower surface of the upper insulating plate 18 and integrated with the upper insulating plate 18. The porous body 30x may be joined to the upper insulating plate 18 using an adhesive, or it may be joined by heat welding or solvent welding. In this case, the handling of the porous body 30x becomes easier, and the productivity of the battery is improved. The porous body 30x overlaps with the upper insulating plate 18 in a range that does not extend from the peripheral edge of the upper insulating plate 18 to the positions of the openings 18b and 18c.

[0041] As shown in Figure 4, the porous body 30y is similar to the porous body 30x in that it is positioned overlapping the lower surface of the upper insulating plate 18. On the other hand, the porous body 30y differs from the ring-shaped porous body 30x in that it covers a wide area of ​​the lower surface of the upper insulating plate 18 and is formed in a substantially disc shape. It is preferable that the porous body 30y, like the porous body 30x, is joined to the lower surface of the upper insulating plate 18 and integrated with the upper insulating plate 18.

[0042] The porous material 30y covers the opening 18c of the upper insulating plate 18. In this case, for example, the risk of a short circuit between the positive electrode lead 20 and the negative electrode 12 of the electrode body 14 through the opening 18c can be reduced. Because the porous material 30y has excellent permeability and electrolyte permeability, it does not impair the function of the opening 18c as an electrolyte passage hole, nor does it impair its function as a gas exhaust hole. The porous material 30y does not cover the opening 18a used for welding the negative electrode lead 21, nor the opening 18b through which the positive electrode lead 20 passes.

[0043] The porous bodies 30x and 30y are preferably formed of a fiber material, particularly a non-woven fabric, and have excellent electrolyte permeability. It is considered that by arranging the porous bodies 30x and 30y between the electrode body 14 and the upper insulating plate 18, the electrolyte can easily permeate into the electrode body 14. In particular, the porous body 30y, which is arranged so as to cover a wide range of the lower surface of the upper insulating plate 18, that is, to cover a wide range of the upper surface of the electrode body 14, is effective for allowing the electrolyte to rapidly permeate into the entire electrode body 14.

[0044] As described above, according to the cylindrical batteries 10, 10x, and 10y having the above configuration, by providing the porous bodies 30, 30x, and 30y respectively, short-circuiting between the electrode body 14 and the grooved portion 22 of the outer can 16 can be more reliably prevented, and at the same time, smooth injection of the electrolyte into the outer can 16 can be achieved. If there is a gap between the peripheral edge of the upper insulating plate 18 and the inner surface of the outer can 16, it is advantageous for electrolyte injection, but there is a risk of short-circuit between the electrode body 14 (positive electrode 11) and the grooved portion 22. In the cylindrical batteries 10, 10x, and 10y, by arranging the insulating porous bodies 30, 30x, and 30y in this gap, short-circuit between the electrode body 14 and the grooved portion 22 can be prevented without impeding the flow of the electrolyte passing through this gap.

[0045] By combining the upper insulating plate 18 and the porous bodies 30, 30x, and 30y, the above functions can be exerted while ensuring the mechanical strength and durability as an insulating member at the upper part of the cylindrical batteries 10, 10x, and 10y. In particular, when the upper insulating plate 18 is interposed between the electrode body 14 and the grooved portion 22 while ensuring a gap between the peripheral edge of the upper insulating plate 18 and the inner surface of the outer can 16, the upper insulating plate 18 is caught by the grooved portion 22 and easily presses the electrode body 14. Thereby, the movement of the electrode body 14 in the axial direction of the outer can 16 can be more effectively suppressed.

[0046] In addition, when the flexible porous bodies 30, 30x, and 30y are brought into contact with the inner surface of the outer can 16, the gap between the upper insulating plate 18 and the inner surface of the outer can 16 can be more reliably blocked while ensuring good productivity compared to the case where a highly rigid insulating plate is press-fitted.

[0047] It should be noted that appropriate design changes can be made to the above embodiment without impairing the purpose of the present disclosure. For example, in the above embodiment, the negative electrode lead 21 is connected to the outer can 16, and the outer can 16 functions as a negative electrode terminal; however, the positive electrode lead 20 may be connected to the outer can 16, and the outer can 16 may function as a positive electrode terminal. In this case, the porous bodies 30, 30x, 30y prevent short-circuit between the grooved portion 22 and the negative electrode 12 of the electrode assembly 14.

[0048] Furthermore, although the porous bodies 30x, 30y are arranged closer to the electrode assembly 14 than the upper insulating plate 18, the porous body may be arranged closer to the sealing body 17 than the upper insulating plate 18, or may be bonded to the upper surface of the upper insulating plate 18 facing the sealing body 17 side. However, when the porous body is arranged closer to the electrode assembly 14 than the upper insulating plate 18, as described above, the infiltration of the electrolyte into the electrode assembly becomes smoother.

[0049] The present disclosure is further illustrated by the following embodiments. Configuration 1: A cylindrical battery comprising an electrode assembly, an electrolyte, a bottomed cylindrical outer can that accommodates the electrode assembly and the electrolyte, and a sealing body that closes an opening of the outer can, wherein a grooved portion that supports the sealing body is formed on the outer can, and a lead extending from a positive electrode or a negative electrode constituting the electrode assembly is connected to the outer can, the cylindrical battery further comprising: an upper insulating plate arranged between the electrode assembly and the sealing body; and an insulating porous body arranged at least radially outward of the upper insulating plate relative to a peripheral edge of the upper insulating plate, and interposed between the electrode assembly and the grooved portion of the outer can. Configuration 2: The cylindrical battery according to Configuration 1, wherein the upper insulating plate is interposed between the electrode assembly and the grooved portion of the outer can. Configuration 3: The cylindrical battery according to Configuration 1 or 2, wherein the porous body is formed of a non-woven fabric. Configuration 4: The cylindrical battery according to any one of Configurations 1 to 3, wherein the porous body is arranged between the upper insulating plate and the electrode assembly. Configuration 5: The cylindrical battery according to any one of Configurations 1 to 4, wherein the porous body has flexibility and is in contact with an inner surface of the outer can.

[0050] 10, 10x, 10y Cylindrical battery, 11 Positive electrode, 12 Negative electrode, 13 Separator, 14 Electrode body, 14z Hollow section, 16 Outer casing, 17 Sealing body, 18 Upper insulating plate, 18a, 18b, 18c Opening, 19 Lower insulating plate, 20 Positive electrode lead, 21 Negative electrode lead, 22 Grooved section, 23 Internal terminal plate, 24 Lower valve body, 25 Insulating member, 26 Upper valve body, 27 Cap, 28 Gasket, 30, 30x, 30y Porous body

Claims

1. A cylindrical battery comprising an electrode body, an electrolyte, a bottomed cylindrical outer container housing the electrode body and the electrolyte, and a sealing body that closes the opening of the outer container, wherein a grooved portion for supporting the sealing body is formed in the outer container, and leads extending from the positive or negative electrode constituting the electrode body are connected to the outer container, further comprising: an upper insulating plate disposed between the electrode body and the sealing body; and an insulating porous body disposed at least radially outward of the insulating plate beyond its periphery and interposed between the electrode body and the grooved portion of the outer container.

2. The cylindrical battery according to claim 1, wherein the upper insulating plate is interposed between the electrode body and the grooved portion of the outer casing.

3. The cylindrical battery according to claim 1 or 2, wherein the porous body is made of a nonwoven fabric.

4. The cylindrical battery according to claim 1 or 2, wherein the porous body is disposed between the upper insulating plate and the electrode body.

5. The cylindrical battery according to claim 1 or 2, wherein the porous body is flexible and in contact with the inner surface of the outer casing.

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