Cylindrical battery

Abstract

A cylindrical battery (10) is characterized in that it comprises: an electrode body (14), a bottomed cylindrical outer can (16) for housing the electrode body (14), a sealing body (17) for blocking the opening of the outer can (16), a current collector plate (32) disposed between the sealing body (17) and the electrode body (14), and a metal plate (40) that is engaged with the side of the sealing body (17) of the current collector plate (32). The metal plate (40) comprises: a protrusion (41) having a top (43) and a side (44) and disposed in the center of the metal plate (40), and a flange (42) disposed around the protrusion (41). The top (43) is engaged with the sealing body (17).

Description

Technical Field

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

[0002] Cylindrical batteries generally include a wound electrode body, a bottomed cylindrical outer can containing the electrode body, and a sealing body that blocks the opening of the outer can. Patent Document 1 discloses a cylindrical battery having a current collector plate inside the outer can, to which a positive electrode lead extending from the positive electrode of the electrode body is connected.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2023 / 281973 Summary of the Invention

[0006] However, for cylindrical batteries, in situations such as an external short circuit occurring while the battery is charging, a large current may be applied to the electrodes, causing them to overheat abnormally. This leads to gas buildup inside the battery, increasing internal pressure and sometimes causing the seal to deform outwards. If the seal deforms outwards, gas will be ejected from the seal side, which is sometimes undesirable from a battery safety perspective.

[0007] Furthermore, when a load is applied from the outside of the battery to the inside, the sealing body or current collector may bend and deform inwards. If this bending occurs, the sealing body or current collector may come into contact with the electrode plates, sometimes causing an internal short circuit and damaging battery performance. Moreover, similar to external short circuits, an internal short circuit can also apply a large current to the electrode, causing abnormal heating.

[0008] The cylindrical battery of one aspect of the present invention is characterized in that it comprises: an electrode body formed by winding a first electrode and a second electrode with a spacer between them; a bottomed cylindrical outer can that houses the electrode body; a sealing body that blocks the opening of the outer can; a current collector plate disposed between the sealing body and the electrode body; and a metal plate that is engaged with the sealing body side surface of the current collector plate. The metal plate comprises: a protrusion having a top and a side portion and disposed in the center of the metal plate; and a flange portion disposed around the protrusion. The top portion is engaged with the sealing body.

[0009] According to one aspect of the present invention, the cylindrical battery can suppress deformation of the sealing body and the current collector. As a result, the battery performance and safety of the cylindrical battery can be ensured. Attached Figure Description

[0010] Figure 1This is an axial cross-sectional view of the cylindrical battery according to the first embodiment.

[0011] Figure 2 This is a perspective view of the electrode body constituting the cylindrical battery of the first embodiment.

[0012] Figure 3 This is a top view of the current collector plate constituting the cylindrical battery of the first embodiment.

[0013] Figure 4 This is an axial cross-sectional view of the current collector plate constituting the cylindrical battery of the first embodiment.

[0014] Figure 5 This is an axial cross-sectional view of the cylindrical battery according to the second embodiment.

[0015] Figure 6 This is a perspective view of the electrode body constituting the cylindrical battery of the second embodiment.

[0016] Figure 7 This is a diagram showing a modified example of the current collector plate that constitutes a cylindrical battery.

[0017] Figure 8 This is a diagram showing a modified example of the current collector plate that constitutes a cylindrical battery.

[0018] Figure 9 This is a diagram showing a modified example of a cylindrical battery. Detailed Implementation

[0019] Hereinafter, an example of an embodiment of the cylindrical battery of the present invention will be described in detail with reference to the accompanying drawings. The embodiment described below is only one example, and the present invention is not limited to the following embodiment. In addition, the present invention includes a way in which the constituent elements of the embodiment described below are selectively combined.

[0020] [First Implementation]

[0021] While referring to Figure 1 and Figure 2 The structure of the cylindrical battery 10, which is the first embodiment, will be described. Figure 1 This is a schematic diagram showing a cross-section of the cylindrical battery 10. Figure 2 This is a three-dimensional view of the electrode body 14 that constitutes the cylindrical battery 10.

[0022] like Figure 1 and Figure 2As shown, the cylindrical battery 10 includes: an electrode body 14 formed by winding a first electrode and a second electrode with a spacer between them; a non-aqueous electrolyte (not shown); an outer container 16 that houses the electrode body 14 and the non-aqueous electrolyte; a sealing body 17 that blocks the opening of the outer container 16; a current collector 32 disposed between the sealing body 17 and the electrode body 14; and a metal plate 40 that is joined to the upper surface of the current collector 32. In this specification, the sealing body 17 side of the cylindrical battery 10 is designated as "upper," and the bottom 16A side of the outer container 16 is designated as "lower." Furthermore, the following description will address the case where the first electrode is a positive electrode 11 and the second electrode is a negative electrode 112.

[0023] The electrode body 14 has a positive electrode 11, a negative electrode 12, and a spacer 13, and has a structure in which the positive electrode 11 and the negative electrode 12 are wound into a spiral shape with the spacer 13 sandwiched between them. The positive electrode 11, the negative electrode 12, and the spacer 13 constituting the electrode body 14 are all strip-shaped elongated bodies, and are alternately stacked in the radial direction of the electrode body 14 by being wound into a spiral shape. To prevent lithium deposition, the negative electrode 12 is formed to be one size larger than the positive electrode 11. That is, the negative electrode 12 is formed to be longer than the positive electrode 11 in both the length and width directions. The spacer 13 is formed to be one size larger than both the positive electrode 11 and the negative electrode 12, for example, two pieces are arranged to sandwich the positive electrode 11.

[0024] 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. In this embodiment, the electrode body 14 has a plurality of positive electrode leads 20. It should be noted that the number of positive electrode leads 20 may also be one. In addition, the number of negative electrode leads 21 may be one or more.

[0025] The positive electrode 11 has a positive electrode core and a positive electrode additive layer formed on the positive electrode core. The positive electrode core can be a foil of a metal that is stable within the potential range of the positive electrode 11, such as aluminum or an aluminum alloy, or a film obtained by depositing the metal on the surface. The positive electrode additive layer contains a positive electrode active material, a conductive agent, and a binder, and is preferably formed on both sides of the positive electrode core except for the exposed portion (not shown) where the positive electrode lead 20 is soldered. For example, the positive electrode 11 can be manufactured by coating the positive electrode core with a positive electrode additive slurry containing a positive electrode active material, a conductive agent, and a binder, drying the coating, and then compressing it to form the positive electrode additive layer on both sides of the positive electrode core.

[0026] The positive electrode composite layer contains particulate lithium metal composite oxides as the positive electrode active material. The lithium metal composite oxide is a composite oxide containing metal elements such as Co, Mn, Ni, and Al in addition to Li. The metal elements constituting the lithium metal composite oxide are, for example, at least one selected from Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y, Zr, Sn, Sb, W, Pb, and Bi. Preferably, it contains at least one selected from Co, Ni, and Mn. Examples of suitable composite oxides include lithium metal composite oxides containing Ni, Co, and Mn, or lithium metal composite oxides containing Ni, Co, and Al.

[0027] Examples of conductive agents included in the positive electrode binder layer include carbon black such as acetylene black and Ketjen black, graphite, carbon nanotubes (CNTs), carbon nanofibers, and graphene. Examples of binders included in the positive electrode binder layer include fluorinated resins such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyimide, acrylic resins, and polyolefins. Additionally, these resins can be used in combination with carboxymethyl cellulose (CMC) or its salts, polyethylene oxide (PEO), etc.

[0028] The negative electrode 12 has a negative electrode core and a negative electrode binder layer formed on the negative electrode core. The negative electrode core can be a foil of a metal that is stable within the potential range of the negative electrode 12, such as copper or a copper alloy, or a film obtained by depositing the metal on the surface. The negative electrode binder layer contains a negative electrode active material, a binder, and a conductive agent as needed, and is preferably formed on both sides of the negative electrode core. The negative electrode 12 can be manufactured by coating the surface of the negative electrode core with a negative electrode binder slurry containing a negative electrode active material and a binder, drying the coating, and then compressing it to form the negative electrode binder layer on both sides of the negative electrode core.

[0029] In the negative electrode composite layer, a carbon material that reversibly absorbs and releases lithium ions is typically included as the negative electrode active material. Suitable examples of carbon materials include natural graphite such as flake graphite, block graphite, and amorphous graphite, as well as artificial graphite such as blocky graphite (MAG) and graphitized mesophase carbon microspheres (MCMB). Alternatively, materials containing at least one of elements alloyed with Li, such as Si and Sn, or materials containing these elements can also be used as the negative electrode active material. Among these, composite materials containing Si are preferred.

[0030] Suitable examples of Si-containing composite materials include materials in which Si particles are dispersed in a SiO2 phase or a silicate phase such as lithium silicate, or materials in which Si particles are dispersed in an amorphous carbon phase. A conductive layer, such as a carbon coating, is formed on the particle surface of this composite material. From the viewpoint of balancing high capacity and high durability of the battery, it is preferable to use both carbon materials and Si-containing composite materials as the negative electrode active material.

[0031] Similar to the case of the positive electrode binder layer, the binder contained in the negative electrode binder layer can also be a fluorinated resin, PAN, polyimide, acrylic resin, polyolefin, etc., with styrene-butadiene rubber (SBR) being preferred. Furthermore, the negative electrode binder layer preferably contains CMC or its salts, polyacrylic acid (PAA) or its salts, polyvinyl alcohol (PVA), etc. It is suitable to use SBR in combination with CMC or its salts, PAA or its salts, etc. The negative electrode binder layer may also contain conductive agents such as CNTs.

[0032] The spacer 13 is made of a porous sheet material with ion permeability and insulation. Specific examples of porous sheets include microporous films, woven fabrics, and nonwoven fabrics. Suitable materials for the spacer 13 include polyolefins such as polyethylene and polypropylene, and cellulose. The spacer 13 can be a single-layer structure or a multi-layer structure. Alternatively, a resin layer with high heat resistance, such as an aromatic polyamide resin, can be formed on the surface of the spacer 13. A filler layer containing inorganic fillers can also be formed at the interface between the spacer 13 and at least one of the positive electrode 11 and the negative electrode 12.

[0033] Non-aqueous electrolytes have lithium-ion conductivity. Non-aqueous electrolytes can be liquid electrolytes (electrolytes) or solid electrolytes.

[0034] Liquid electrolytes (electrolytes) comprise a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. The non-aqueous solvent can be, for example, 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 derivatives (e.g., fluoroethylene carbonate (FEC)) obtained by substituting at least a portion of the hydrogen atoms of these solvents with halogen atoms such as fluorine. The electrolyte salt is, for example, a lithium salt such as LiPF6.

[0035] As a solid electrolyte, examples include solid or gel-like polymer electrolytes and inorganic solid electrolytes. As an inorganic solid electrolyte, materials known in all-solid-state lithium-ion secondary batteries (e.g., oxide-based solid electrolytes, sulfide-based solid electrolytes, halogen-based solid electrolytes, etc.) can be used. Polymer electrolytes may contain, for example, a lithium salt and a matrix polymer, or a non-aqueous solvent, a lithium salt, and a matrix polymer. As a matrix polymer, for example, a polymer material that absorbs a non-aqueous solvent and gels. Examples of polymer materials include fluoropolymers, acrylic resins, and polyether resins.

[0036] Insulating plates 18 and 19 are respectively disposed above and below the electrode body 14. The positive electrode lead 20 extends toward the sealing body 17 through a through hole 18A provided in the insulating plate 18 and a through hole 32A provided in the current collector plate 32. Moreover, the positive electrode lead 20 is bent along the upper surface of the recess 34 of the current collector plate 32 and joined by welding or the like by being clamped between the current collector plate 32 and the metal plate 40. By clamping the positive electrode lead 20 with the current collector plate 32 and the metal plate 40, the workability of welding the positive electrode lead 20 is improved, in addition to making it difficult for the positive electrode lead 20 to detach from the surface of the current collector plate 32. Details will be described later. The current collector plate 32 is electrically connected to the sealing body 17. Therefore, the sealing body 17 becomes the positive terminal. In addition, in this embodiment, the negative electrode lead 21 extends toward the bottom 16A of the outer can 16 through the outside of the insulating plate 19. Furthermore, the negative lead 21 is joined to the inner surface of the bottom 16A of the outer can 16 by welding or the like. Thus, the outer can 16 becomes the negative terminal. It should be noted that the negative lead 21 may also extend from the center of the insulating plate 19 toward the bottom 16A of the outer can 16. Alternatively, the negative lead 21 may be omitted, allowing the negative electrode core to be exposed at the outermost periphery of the electrode body 14, and this negative electrode core to abut against the inner surface of the outer can 16.

[0037] The outer can 16 is a bottomed cylindrical metal container with an opening on one axial side. The opening of the outer can 16 is blocked by a sealing body 17. A gasket 24 is provided between the outer can 16 and the sealing body 17 to ensure the airtightness of the battery interior. In addition, the gasket 24 ensures the insulation between the outer can 16 and the sealing body 17. That is, the gasket 24 serves as a sealing member for maintaining the airtightness of the battery interior and as an insulating member for insulating the outer can 16 and the sealing body 17.

[0038] A groove 22 is formed in the outer can 16, a portion of which protrudes inward from the sidewall and supports the sealing body 17 and the current collector 32. The groove 22 is preferably formed in a ring shape along the circumference of the outer can 16, and supports the sealing body 17 and the current collector 32 on its upper surface. The groove 22 can be formed, for example, by spinning a portion of the sidewall of the outer can 16 radially inward and then recessing it radially inward. The sealing body 17 and the current collector 32 are fixed to the upper part of the outer can 16 by the groove 22 and the open end of the outer can 16 that is hewn to tighten the sealing body 17.

[0039] A gas outlet is provided at the bottom 16A of the outer canister 16, which opens when the internal pressure of the cylindrical battery 10 reaches a predetermined pressure. In other words, in this embodiment, it is configured to release gas from the gas outlet at the bottom 16A of the outer canister 16 when the internal pressure of the battery increases due to abnormal heating of the electrode body 14, etc.

[0040] An annular groove 23 is formed at the bottom 16A of the outer can 16, and the portion surrounded by the groove 23 becomes a gas outlet. The groove 23 can also be a C-shape when viewed from below, but from the viewpoint of improving the fracture resistance when the internal pressure rises, it is preferable to form it into a perfect circle shape when viewed from below. The groove 23 is, for example, an engraving formed from the outer surface side of the bottom 16A.

[0041] As described above, the sealing body 17 functions to block the opening of the outer can 16. In this embodiment, the sealing body 17 is composed of a sealing plate 30. It should be noted that the configuration of the sealing body 17 is not limited to this, as long as it can block the opening of the outer can 16. The sealing body 17 may also have a structure in which multiple components are stacked axially. For example, the sealing body 17 may also have a cover member on the upper part of the sealing plate 30.

[0042] A protrusion 31 protruding outward from the center of the sealing plate 30 is provided. The protrusion 31 has a roughly circular shape when viewed from above. As will be described later, the sealing plate 30 joins the metal plate 40 near its center. Therefore, the diameter of the protrusion 31 on the sealing plate 30 is smaller than the diameter of the top 43 on the metal plate 40. The height of the protrusion 31 is not particularly limited, for example, it is 0.5 mm or more and 5.0 mm or less. It should be noted that the lower surface of the sealing plate 30 may also have an overall flat shape.

[0043] As a material for the sealing plate 30, a metal with aluminum as its main component can be cited as an example. As described above, the sealing plate 30 is hemmed and fixed to the opening of the outer can 16 via the gasket 24.

[0044] The current collector 32 is disposed between the sealing plate 30 and the electrode body 14. The current collector 32 has a peripheral portion 33 located on the outer periphery of the current collector 32, and a recess 34 provided on the radially inner side of the peripheral portion 33 and recessed downward relative to the peripheral portion 33.

[0045] The peripheral portion 33 has an annular shape and abuts against the lower surface of the sealing plate 30. The peripheral portion 33 is joined to the sealing plate 30 by laser welding. The number and area of ​​the welded portions between the peripheral portion 33 and the sealing plate 30 are set, for example, taking into account the joint strength and resistance. The peripheral portion 33 is hemmed and fixed to the opening of the outer can 16 via the gasket 24. By hemming and fixing the peripheral portion 33 to the opening of the outer can 16, the current collector 32 can be securely fixed to the upper part of the outer can 16.

[0046] The recess 34 has a perfectly circular shape when viewed from above. A positive lead 20 is attached to the upper surface of the recess 34. The depth of the recess 34, that is, the axial length from the upper surface of the peripheral portion 33 to the upper surface of the recess 34, is, for example, more than 0.1 mm and less than 5.0 mm. The recess 34 is flat and is configured to be substantially parallel to the peripheral portion 33.

[0047] A through hole 32A is provided in the center of the recess 34. As described above, the positive electrode lead 20 extending from the positive electrode 11 passes through the through hole 32A. The size of the through hole 32A can be appropriately set according to the number and shape of the positive electrode lead 20. The diameter of the through hole 32A is, for example, more than 20% and less than 60% of the diameter of the current collector 32.

[0048] The following is further reference. Figure 3 and Figure 4 The metal plate 40 is described in detail. Figure 3 This is a top view of metal plate 40. Figure 4 This is an axial cross-sectional view of metal plate 40. It should be noted that... Figure 3 In the diagram, the area where the metal plate 40 is formed is shaded.

[0049] like Figure 1 , Figure 3 and Figure 4 As shown, the metal plate 40 is a component disposed between the sealing plate 30 and the current collector plate 32, and clamps the positive electrode lead 20 through the metal plate 40 and the current collector plate 32. For example, a metal with aluminum as its main component can be used as the material for the metal plate 40.

[0050] The metal plate 40 has a protrusion 41 disposed at the center of the metal plate 40, and a flange 42 disposed around the protrusion 41 and abutting against the positive lead 20. The flange 42 is configured to surround the protrusion 41 around the entire circumference and has an annular shape.

[0051] The protrusion 41 is a portion that bulges upwards further than the flange 42. The protrusion 41 has a top 43 that is approximately circular in shape when viewed from above, and a plurality of side portions 44 connecting the top 43 to the flange 42. In this embodiment, the protrusion 41 has four side portions 44. Furthermore, the top 43 is flat and is configured to be approximately parallel to the flange 42. It should be noted that the shape of the top 43 is not limited to an approximately circular shape when viewed from above; it can also be an approximately rectangular shape when viewed from above.

[0052] Here, the top 43 is joined to the sealing plate 30. More specifically, the top 43 is joined to the periphery of the protrusion 31 on the lower surface of the sealing plate 30. In this embodiment, the top 43 is joined to the sealing plate 30 by laser welding. The number and area of ​​the welded portions between the top 43 and the sealing plate 30 are set, for example, taking into account the bonding strength and resistance. Generally, the larger the area of ​​the welded portion, the higher the bonding strength and the lower the resistance. From the viewpoint of improving the bonding strength between the metal plate 40 and the sealing plate 30, it is preferable that the welded portion is formed into a circular shape when viewed from above. It should be noted that the joining method between the top 43 and the sealing plate 30 is not limited to laser welding; it can also be joined by adhesives or the like.

[0053] By joining the top 43 of the metal plate 40 to the sealing plate 30, the strength of the central portion of the sealing plate 30 can be increased. Thus, for example, when the internal pressure increases due to a battery malfunction, deformation of the sealing plate 30 towards the outside of the battery is suppressed when a load pushing it outwards is applied to the sealing plate 30. As a result, the release of gas from the top of the battery (the sealing plate 30 side) can be suppressed, improving battery safety.

[0054] Furthermore, by engaging the top 43 of the metal plate 40 with the sealing plate 30, bending deformation of the sealing plate 30, current collector 32, and metal plate 40 towards the inside of the battery is suppressed when a load is applied from the outside to the inside of the battery. As a result, internal short circuits caused by contact between the deformed sealing plate 30, current collector 32, and metal plate 40 and the negative electrode 12 can be suppressed, thus ensuring battery performance.

[0055] Side portion 44 is a post that connects top 43 to flange portion 42. All four side portions 44 have the same shape.

[0056] In this embodiment, the side portion 44 extends in a direction inclined relative to the axial direction. The angle of inclination of the extending direction of the side portion 44 relative to the axial direction is, for example, 20° or more and 70° or less, preferably 30° or more and 60° or less. By setting this angle of inclination to 30° or more and 60° or less, the bending deformation of the sealing plate 30, the current collector plate 32, and the metal plate 40 towards the inside of the battery is further suppressed when a load is applied from the outside of the battery to the inside of the battery. It should be noted that the side portion 44 may also extend axially. That is, the side portion 44 may also be configured to be substantially perpendicular to the flange portion 42 and the top 43.

[0057] like Figure 3 As shown, the four side portions 44 are arranged at equal angular intervals in the circumferential direction. By arranging the side portions 44 at equal angular intervals in the circumferential direction, the load applied to the side portions 44 is distributed when a load is applied to the metal plate 40 from the outside of the battery, making the side portions 44 less prone to deformation. As a result, the strength of the central portion of the sealing plate 30 is easily improved, and the effects of the present invention are more significantly realized.

[0058] Furthermore, the side portion 44 is preferably connected to at least 10% of the outer periphery of the top 43, and more preferably to at least 15% of the outer periphery of the top 43. In this case, the strength of the side portion 44 is increased, which easily improves the strength of the central portion of the sealing plate 30, and the effects of the present invention are more significantly realized.

[0059] Furthermore, through holes 40A are formed between adjacent side portions 44 in the circumferential direction. That is, four through holes 40A are formed on the side of the protrusion 41. By providing through holes 40A, gas is generated inside the battery when an abnormality occurs. When the internal pressure of the battery increases, this gas flows into the space above the metal plate 40 through the through holes 40A. As a result, the internal pressure of the battery can be reduced.

[0060] It should be noted that the metal plate 40 may also not have a through hole 40A. That is, the side portion 44 of the protrusion 41 may also be formed over the entire circumference of the top 43. By forming the side portion 44 over the entire circumference of the top 43, the strength of the metal plate 40 can be further increased.

[0061] The height of the protrusion 41 is not particularly limited as long as the top 43 can engage with the sealing plate 30, for example, it is more than 0.5mm and less than 5.0mm.

[0062] A flange 42 is disposed around the protrusion 41 and is positioned opposite the recess 34 of the current collector plate 32, sandwiching the positive lead 20. The flange 42 is laser welded to the positive lead 20 and the metal plate 40, for example, by means of laser welding.

[0063] The size of the flange portion 42 is not particularly limited as long as it can be used to engage the positive lead 20; for example, it is the size of approximately the entire area covering the upper surface of the recess 34 of the current collector plate 32. The radial length of the flange portion 42 is, for example, more than 30% and less than 70% of the radius of the metal plate 40.

[0064] [Second Implementation]

[0065] Next, while referring to Figure 5 and Figure 6 The structure of the cylindrical battery 10X, which is the second embodiment, will be described. Figure 5 This is a schematic diagram showing the cross-section of a cylindrical battery 10X. Figure 6 This is a perspective view of the electrode body 14 constituting the cylindrical battery 10X. Hereinafter, for configurations common to the first embodiment, the same reference numerals will be used and repeated descriptions will be omitted, and the differences from the first embodiment will be mainly described.

[0066] like Figure 5 As shown, the cylindrical battery 10X of the second embodiment is common to the cylindrical battery 10 of the first embodiment in that it includes an electrode body 14, a non-aqueous electrolyte (not shown), an outer can 16 for housing the electrode body 14 and the non-aqueous electrolyte, a sealing body 17 for blocking the opening of the outer can 16, a current collector 32 disposed between the sealing body 17 and the electrode body 14, and a metal plate 40 bonded to the upper surface of the current collector 32. On the other hand, as will be described in detail later, the electrode body 14 of the second embodiment does not have a positive electrode lead 20 (see reference 10). Figure 1 ) and negative lead 21 (refer to Figure 1 This differs from the first embodiment. Furthermore, the cylindrical battery 10X in the second embodiment does not have insulating plates 18 and 19 respectively disposed above and below the electrode body 14 (see [reference]). Figure 1 This differs from the first implementation.

[0067] like Figure 6 As shown, the electrode body 14 has a positive electrode 11, a negative electrode 12, and a spacer 13, and has a structure in which the positive electrode 11 and the negative electrode 12 are wound into a spiral shape with the spacer 13 in between. The positive electrode 11, the negative electrode 12, and the spacer 13 constituting the electrode body 14 are all strip-shaped long strips, and are alternately stacked in the radial direction of the electrode body 14 by being wound into a spiral shape. In addition, the positive electrode 11 protrudes upward more than the negative electrode 12 and the spacer 13, and the negative electrode 12 protrudes downward more than the positive electrode 11 and the spacer 13.

[0068] The positive electrode 11 has a positive electrode core exposure portion 52 at its upper axial end, which exposes the positive electrode core 50 without the positive electrode binder layer 51. The positive electrode core exposure portion 52 is provided within the range from the end of the long strip-shaped positive electrode 11 at the beginning of winding to the end of winding. Similarly, the negative electrode 12 has a negative electrode core exposure portion 62 at its lower axial end, which exposes the negative electrode core 60 without the negative electrode binder layer 61. The negative electrode core exposure portion 62 is provided within the range from the end of the long strip-shaped negative electrode 12 at the beginning of winding to the end of winding. Therefore, the upper axial end of the electrode body 14 is composed of the positive electrode core exposure portion 52, and the lower axial end of the electrode body 14 is composed of the negative electrode core exposure portion 62. The width of the exposed portion 52 of the positive electrode core is, for example, more than 2 mm and less than 20 mm, and the width of the exposed portion 62 of the negative electrode core is, for example, more than 2 mm and less than 20 mm.

[0069] like Figure 5 As shown, the exposed positive electrode core 52 extends substantially parallel to the axial direction of the electrode body 14 from the upper end face of the electrode body 14. Furthermore, the exposed positive electrode core 52 bends radially inward at its upper end and engages with the lower surface of the flange 42 of the metal plate 40. By engaging the exposed positive electrode core 52 with the metal plate 40, the contact area between the exposed positive electrode core 52 and the metal plate 40 is increased, thus improving the contact area with the positive electrode lead 20 (see reference 20). Figure 1 Compared to the case of ), it can reduce the internal resistance of the positive electrode 11.

[0070] In addition, such as Figure 5 As shown, the exposed negative electrode core 62 extends substantially parallel to the axial direction of the electrode body 14 from its lower end face. Furthermore, the exposed negative electrode core 62 bends radially inward at its lower end and engages with the inner surface of the bottom 16A of the outer can 16. It should be noted that in this embodiment, the exposed negative electrode core 62 engages with the outer can 16, but similarly to the first embodiment, the negative electrode lead 21 may also engage with the inner surface of the bottom 16A of the outer can 16. That is, the electrode body 14 may also lack the positive electrode lead 20 and only have the negative electrode lead 21.

[0071] The metal plate 40 in the second embodiment, like that in the first embodiment, has a protrusion 41 in its central portion. Furthermore, the protrusion 41 has a top 43 and a side portion 44, with the top 43 engaging with the sealing plate 30. Even when the exposed positive electrode core 52 is engaged with the lower surface of the metal plate 40, the engagement of the top 43 of the metal plate 40 with the sealing plate 30 enhances the strength of the central portion of the sealing plate 30.

[0072] As described above, by disposing a metal plate 40 with a protrusion 41 between the sealing body 17 and the current collector 32, and engaging the top 43 of the protrusion 41 with the sealing body 17, the strength of the central portion of the sealing plate 30 can be improved. Consequently, for example, when the internal pressure increases due to a battery malfunction, deformation of the sealing plate 30 towards the outside of the battery is suppressed when a load pushing the sealing plate 30 outwards is applied. Furthermore, bending deformation of the sealing plate 30, the current collector 32, and the metal plate 40 towards the inside of the battery is suppressed when a load is applied from the outside of the battery. As a result, battery performance and battery safety can be ensured.

[0073] It should be noted that the above embodiments can be appropriately modified within the scope of not affecting the purpose of the present invention. For example, such as Figure 7 As shown, a thin-walled portion 45, formed by a recessed lower surface, can also be provided on the side surface 44 of the metal plate 40. The thin-walled portion 45 functions as a deformable portion that preferentially deforms when the cylindrical battery 10 is pressed from the radially outer side to the radially inner side. Furthermore, by providing the thin-walled portion 45 on the lower surface of the side surface 44, when the cylindrical battery 10 is pressed from the radially outer side to the radially inner side, the side surface 44 deforms upwards from the thin-walled portion 45. In other words, by providing the thin-walled portion 45 on the lower surface of the side surface 44, downward deformation of the metal plate 40 is suppressed when the cylindrical battery 10 is pressed from the radially outer side to the radially inner side. This suppresses the occurrence of internal short circuits caused by contact between the metal plate 40 and the negative electrode 12, ensuring battery performance.

[0074] Thin-walled portions 45 are formed, for example, circumferentially. The number of thin-walled portions 45 provided on the side portions 44 can be one or more. It should be noted that when the metal plate 40 has multiple side portions 44, thin-walled portions 45 are preferably provided on all of the side portions 44.

[0075] The size and shape of the thin-walled portion 45 are not particularly limited as long as it fulfills its function as the aforementioned deformable portion. Figure 7 In the example shown, a thin-walled portion 45 is formed by forming a V-shaped groove 46 on the lower surface of the side portion 44. The minimum thickness of the thin-walled portion 45 is, for example, more than 30% and less than 70% of the thickness of the portion of the side portion 44 excluding the thin-walled portion 45.

[0076] In addition, such as Figure 8As shown, the side portion 44 of the metal plate 40 can also have a curved shape. Because the side portion 44 has a curved shape, when the cylindrical battery 10 is pressed from the radially outer side to the radially inner side, the side portion 44 is folded and deformed starting from the curved portion. In other words, because the side portion 44 has a curved shape, the downward deformation of the metal plate 40 is suppressed when the cylindrical battery 10 is pressed from the radially outer side to the radially inner side. Therefore, the occurrence of internal short circuits caused by contact between the metal plate 40 and the negative electrode 12 can be suppressed, ensuring battery performance.

[0077] Furthermore, in the above embodiment, the case where the first electrode is a positive electrode 11 and the second electrode is a negative electrode 12 has been described, but it is also possible for the first electrode to be a negative electrode 12 and the second electrode to be a positive electrode 11. That is, in the first embodiment, the negative electrode lead 21 extending from the negative electrode 12 may be connected to the current collector 32, and the positive electrode lead 20 extending from the positive electrode 11 may be connected to the outer can 16. In addition, in the second embodiment, the negative electrode 12 may protrude upwards more than the positive electrode 11 and the spacer 13, and the positive electrode 11 may protrude downwards more than the negative electrode 12 and the spacer 13.

[0078] Furthermore, in the above embodiment, the top 43 of the protrusion 41 of the metal plate 40 is flat, but the top 43 may also have an uneven shape. Additionally, as... Figure 9 As shown, the protrusion 41 of the metal plate 40 may also have multiple height differences. Furthermore, in addition to the top 43 of the protrusion 41 engaging with the lower surface of the sealing plate 30, the side portion 44 of the protrusion 41 may also abut against the inner surface of the protrusion 31 of the sealing plate 30. By configuring it as described above, the space for gas flow increases when the internal pressure of the battery increases, thus further reducing the internal pressure of the battery.

[0079] The present invention will be further illustrated by the following embodiments.

[0080] Configuration 1: A cylindrical battery comprising: an electrode body formed by winding a first electrode and a second electrode with a spacer between them; a bottomed cylindrical outer can containing the electrode body; a sealing body blocking the opening of the outer can; a current collector plate disposed between the sealing body and the electrode body; and a metal plate joined to the sealing body side surface of the current collector plate, wherein the metal plate has a protrusion having a top and a side portion and disposed in the center of the metal plate, and a flange portion disposed around the protrusion, the top portion being joined to the sealing body.

[0081] Configuration 2: The cylindrical battery according to Configuration 1, wherein the electrode body has an electrode lead connected to the first electrode, and the electrode lead is held by the current collector and the metal plate.

[0082] Configuration 3: The cylindrical battery according to Configuration 1, wherein the first electrode has a first electrode core and a first electrode compound layer formed on the surface of the first electrode core, and a first electrode core exposed portion is provided at the end of the electrode body on the sealing body side, wherein the first electrode core exposed portion is engaged with the electrode body side surface of the current collector.

[0083] Configuration 4: A cylindrical battery according to any one of configurations 1 to 3, wherein the protrusion has a through hole.

[0084] Configuration 5: A cylindrical battery according to any one of configurations 1 to 4, wherein the protrusion has a plurality of the side surfaces, which are arranged at equal angular intervals in the circumferential direction.

[0085] Configuration 6: A cylindrical battery according to any one of configurations 1 to 5, wherein the side portion extends in a direction inclined relative to the axial direction of the outer can, and the angle of inclination of the extension direction of the side portion relative to the axial direction of the outer can is 30° or more and 60° or less.

[0086] Configuration 7: A cylindrical battery according to any one of configurations 1 to 6, wherein the peripheral portion provided on the outer periphery of the current collector plate is joined to the sealing body.

[0087] Configuration 8: A cylindrical battery according to any one of configurations 1 to 7, wherein the current collector is hewn and fixed to the opening of the outer can.

[0088] Configuration 9: A cylindrical battery according to any one of configurations 1 to 8, wherein the protrusion has a plurality of height differences.

[0089] Configuration 10: A cylindrical battery according to any one of configurations 1 to 9, wherein at least a portion of the side portion abuts against the sealing body.

[0090] Explanation of reference numerals in the attached figures

[0091] 10, 10X Cylindrical Battery (Battery), 11 Positive Electrode (First Electrode), 12 Negative Electrode (Second Electrode), 13 Spacer, 14 Electrode Body, 16 Outer Can, 16A Bottom, 17 Sealing Body, 18 Insulating Plate, 18A Through Hole, 19 Insulating Plate, 20 Positive Lead, 21 Negative Lead, 22 Groove, 23 Slot, 24 Gasket, 30 Sealing Plate, 31 Protrusion, 32 Current Collector, 32A Through Hole, 33 Peripheral Part, 34 Recess, 40 Metal Plate, 41 Protrusion, 42 Flange, 43 Top, 44 Side Part, 45 Thin-Walled Part, 46 Slot, 50 Positive Electrode Core, 51 Positive Electrode Adhesive Layer, 52 Exposed Positive Electrode Core, 60 Negative Electrode Core, 61 Negative electrode binder layer, 62 negative electrode core exposed portion.

Claims

1. A cylindrical battery, comprising: The first electrode and the second electrode are separated by a spacer, forming an electrode body wound together. A bottomed cylindrical outer container housing the electrode body The sealing body that blocks the opening of the outer can; The current collector plate disposed between the sealing body and the electrode body, and A metal plate that engages with the sealing body side of the current collector. The metal plate has the following characteristics: A protrusion having a top and side portion and located in the center of the metal plate, and A flange portion disposed around the protrusion. The top is engaged with the sealing body.

2. The cylindrical battery according to claim 1, wherein, The electrode body has electrode leads that are connected to the first electrode. The electrode leads are held between the current collector and the metal plate.

3. The cylindrical battery according to claim 1, wherein, The first electrode has a first electrode core and a first electrode compound layer formed on the surface of the first electrode core. The end of the electrode body on the sealing body side is provided with a first electrode core exposed portion, which exposes the first electrode core. The exposed portion of the first electrode core is engaged with the electrode side surface of the current collector plate.

4. The cylindrical battery according to claim 1, wherein, The protrusion has a through hole.

5. The cylindrical battery according to claim 1, wherein, The protrusion has a plurality of said side portions. The side portions are arranged at equal angular intervals in the circumferential direction.

6. The cylindrical battery according to claim 1, wherein, The side portion extends in a direction inclined relative to the axial direction of the outer can. The angle of inclination of the extension direction of the side portion relative to the axial direction of the outer can is more than 30° and less than 60°.

7. The cylindrical battery according to claim 1, wherein, The peripheral portion of the current collector plate is joined to the sealing body.

8. The cylindrical battery according to claim 1, wherein, The current collector is hewn and fixed to the opening of the outer can.

9. The cylindrical battery according to claim 1, wherein, The protrusion has multiple height differences.

10. The cylindrical battery according to claim 1, wherein, At least a portion of the side surface abuts against the sealing body.

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