Cylindrical secondary battery

Abstract

A cylindrical secondary battery (10) includes an electrode group (14), a cylindrical metal can (16) having an opening at one end and housing the electrode group, a current collector member connected to the electrode group in the interior of the metal can, a sealing body having an electrode terminal exposed to the outside and closing the opening, and a conductive member (60) connected to the current collector member and the sealing body in the interior of the metal can. The conductive member has a center-side plate portion (61) along a plane orthogonal to the center axis, inclined portions (62) extending from a plurality of positions in the circumferential direction of the outer periphery of the center-side plate portion toward the outer peripheral side in the inclined direction, and outer peripheral-side plate portions connected to the outer peripheral-side ends of the inclined portions. In each of the inclined portions, thin portions (68) extending to both circumferential ends of the inclined portions and having a thickness smaller than that of adjacent portions on both sides are formed at a connection portion connected to the center side plate portion.

Description

Technical Field

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

[0002] Cylindrical secondary batteries using cylindrical metal cans have long been known. For example, in non-aqueous electrolyte secondary batteries, an electrode assembly and a non-aqueous electrolyte are housed within the metal can. The electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator between the positive and negative electrode plates. Cylindrical non-aqueous electrolyte secondary batteries also possess a wound electrode assembly formed by winding the positive and negative electrode plates into a spiral shape with the separator in between.

[0003] Patent Document 1 describes a cylindrical secondary battery in which a wound electrode assembly is housed within a cylindrical metal electrolytic cell (metal can). Leads (conducting components) are welded to the inner surface of a cap (sealing body) that blocks the opening of the electrolytic cell and to the upper surface of an upper current collector plate (current collector component). The leads have a plate-shaped top and sidewalls extending obliquely downwards from the outer periphery of the top. In the sidewalls, slits are formed longitudinally from the lower end at circumferential intervals. The lower end of the sidewalls bends radially outwards. This allows for easy and reliable welding of the upper current collector plate to the leads by applying appropriate pressure, resulting in a battery with low resistance and excellent output characteristics.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2006-331993 Summary of the Invention

[0007] In the configuration described in Patent Document 1, after placing the conductive member on the current collector and applying pressure to bring the sealing body close to the current collector, thus pressing the conductive member and the sealing body together, it is possible that the conductive member may not be able to adequately absorb the circumferential height deviation between the current collector and the sealing body. Therefore, it is possible to apply a large load to the electrode assembly concentrated in a portion of the circumferential direction of the current collector.

[0008] The cylindrical secondary battery disclosed herein comprises: an electrode assembly formed by winding a positive electrode plate and a negative electrode plate separated by a separator; a cylindrical metal can having an opening at one end and housing the electrode assembly; a current collector connected to the electrode assembly inside the metal can; a sealing body having electrode terminals exposed to the outside and blocking the opening; and a conductive member connected to the current collector and the sealing body inside the metal can. The conductive member has: a central side plate portion along a plane orthogonal to a central axis; an inclined portion extending from multiple circumferential positions on the outer periphery of the central side plate portion in an inclined direction to the outer periphery; and an outer peripheral side plate portion connected to the outer peripheral ends of each of the plurality of inclined portions and having one side connected to the sealing body. In each of the plurality of inclined portions, a thin-walled portion is formed at the connection portion connected to the central side plate portion, the thin-walled portion extending to both circumferential ends of the inclined portion and having a thickness smaller than the adjacent portions on both sides.

[0009] According to the cylindrical secondary battery disclosed herein, when the conductive component is pressed against the sealing body, it is possible to suppress excessive load on the electrode assembly from the circumferential portion of the current collector. Attached Figure Description

[0010] Figure 1 This is an axial cross-sectional view of a cylindrical secondary battery as an example of an implementation method.

[0011] Figure 2 This is a perspective view obtained by removing the conductive component and viewing it from an obliquely upward side in one embodiment.

[0012] Figure 3 yes Figure 2 The diagram shows the AA cross-section of the conductive component.

[0013] Figure 4 Viewed from above Figure 2 The diagram shows the conductive component.

[0014] Figure 5 This is a perspective view of a cylindrical secondary battery in another embodiment, obtained by removing the conductive component and viewing it from an obliquely upward side. Detailed Implementation

[0015] Hereinafter, an example of an embodiment of the cylindrical secondary battery of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that the cylindrical secondary battery of the present disclosure is not limited to the embodiment described below.

[0016] The following examples illustrate cylindrical secondary batteries that are non-aqueous electrolyte secondary batteries, but this disclosure is not limited to these examples. Cylindrical secondary batteries can also be aqueous solution-based secondary batteries.

[0017] Figure 1This is a cross-sectional view of a cylindrical secondary battery 10 as an example of an implementation method. (See attached image.) Figure 1 As shown, the cylindrical secondary battery 10 is a non-aqueous electrolyte secondary battery, having a positive electrode plate 11, a negative electrode plate 12, and a separator 13, and an electrode assembly 14 formed by winding the positive electrode plate 11 and the negative electrode plate 12 with the separator 13 in between. Furthermore, the cylindrical secondary battery 10 includes a bottomed cylindrical metal can 16 for housing the electrode assembly 14, a sealing body 17 that blocks the opening of the metal can 16, an upper current collector 50, and a conductive member 60.

[0018] The upper current collector 50 is connected to the electrode assembly 14 as described later. The conductive member 60 connects the upper current collector 50 to the sealing body 17 as described later. Furthermore, regarding the conductive member 60, when the sealing body 17 is pressurized after the conductive member 60 is placed on the upper current collector 50, causing the conductive member 60 to press against the sealing body 17, it can absorb any circumferential height deviation between the upper current collector 50 and the sealing body 17. This suppresses excessive load on the electrode assembly 14 from the circumferential portion of the upper current collector 50. This will be described in detail later.

[0019] A non-aqueous electrolyte is housed in the metal can 16 along with the electrode assembly 14. The metal can 16 has a groove 22 formed in the side wall, a sealing body 17 is supported by the groove 22, and a plug is provided at the upper end of the opening 16a, which is one end of the metal can 16. Hereinafter, for ease of explanation, the sealing body 17 side of the cylindrical secondary battery 10 will be described as upper, and the bottom side of the metal can 16 will be described as lower. The metal can 16 is usually made of a metal with iron as the main component, such as a material with iron plated with nickel, but it may also be made of a metal with aluminum or the like as the main component.

[0020] It should be noted that by forming a localized thin-walled section at the bottom of the metal can, a fracture-prone section that is prone to breakage due to an increase in the internal pressure of the battery can also be formed. In this case, if the internal pressure of the battery increases, the fracture of the fracture-prone section causes deformation of the inner side of the fracture-prone section, which is then pressed down, allowing the high-temperature and high-pressure gases inside the battery to be discharged through the opening formed on the inner side.

[0021] Non-aqueous electrolytes possess ionic conductivity (e.g., lithium-ion conductivity). A non-aqueous electrolyte comprises a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. The non-aqueous electrolyte is not limited to a liquid electrolyte (non-aqueous electrolyte solution) and can also be a solid electrolyte using a gel polymer, etc. The cylindrical secondary battery 10 is preferably a lithium-ion battery. The electrolyte salt, for example, uses lithium salts such as LiBF4 and LiPF6. The non-aqueous solvent includes, for example, esters, ethers, nitriles, amides, and mixtures of two or more of these solvents, such as ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and methyl propionate (MP). The non-aqueous solvent may contain halogen-substituted products in which at least a portion of the hydrogen atoms of the aforementioned solvents are replaced by halogen atoms such as fluorine.

[0022] Examples of halogen substitutes include fluorocyclic carbonates such as fluoroethylene carbonate (FEC), fluorochain carbonates, and fluorochain carboxylic acid esters such as methyl fluoropropionate (FMP). From the perspective of suppressing the degradation of charge-discharge cycle characteristics of non-aqueous electrolyte secondary batteries or improving input characteristics, the non-aqueous electrolyte preferably contains 5% by mass or more of FEC relative to the mass of the non-aqueous electrolyte, and more preferably contains 5% to 15% by mass of FEC.

[0023] As solid electrolytes, examples include solid or gel-like polymer electrolytes and inorganic solid electrolytes. Polymer electrolytes may contain, for example, lithium salts and a matrix polymer, or non-aqueous solvents, lithium salts and a matrix polymer. As a matrix polymer, for example, a polymer material that gels by absorbing a non-aqueous solvent is used. As polymer materials, for example, fluoropolymers, acrylic resins, polyether resins, etc., can be used. As inorganic solid electrolytes, for example, materials known in all-solid-state lithium-ion secondary batteries (e.g., oxide-based solid electrolytes, sulfide-based solid electrolytes, halide-based solid electrolytes, etc.) can be used.

[0024] As described above, the electrode assembly 14 has a spiral structure in which a positive electrode plate 11 and a negative electrode plate 12 are wound together in a spiral shape with a separator 13 in between. The positive electrode plate 11, the negative electrode plate 12, and the separator 13 are all strip-shaped elongated bodies, which are alternately stacked in the radial direction of the electrode assembly 14 by being wound into a spiral shape. To prevent lithium deposition, the negative electrode plate 12 is formed to be one size larger than the positive electrode plate 11. That is, the negative electrode plate 12 is formed to be longer than the positive electrode plate 11 in both the long and short side directions. The separator 13 is formed to be at least one size larger than the positive electrode plate 11, for example, two sheets are arranged to sandwich the positive electrode plate 11.

[0025] In the electrode assembly 14, an upper outlet portion 31, which is longer upwards than other portions in the long side direction of the positive electrode core 30 forming the positive electrode plate 11, is formed on a portion of the positive electrode core 30. The upper end of this upper outlet portion 31 is welded to the lower surface of an upper current collector 50 disposed on the upper side of the electrode assembly 14 inside the metal can 16. The upper current collector 50 is formed of metal in a circular plate shape and has a central hole formed in its center. Thus, the upper current collector 50 is electrically connected to the positive electrode core 30. The upper current collector 50 is electrically connected to the sealing body 17, which will be described later, via a conductive member 60.

[0026] Furthermore, in the electrode assembly 14, the negative electrode core 40 forming the negative electrode plate 12 extends downward compared to the other parts located at the lower end of the electrode assembly 14. The lower end of the negative electrode core 40 is welded to the upper surface of the lower current collector 52 disposed on the lower side of the electrode assembly 14. The lower current collector 52 has a bottomed lower cylindrical portion 54 that bulges downward at the center of the circular plate portion 53, and the lower surface of the lower cylindrical portion 54 is welded to the bottom of the metal can 16. Thus, the negative electrode core 40 is electrically connected to the metal can 16, and the metal can 16 becomes the negative terminal.

[0027] The positive electrode plate 11 has a positive electrode core 30 and positive electrode binder layers 33 formed on both sides of the core. The positive electrode core 30 can be a foil of a metal that is stable within the potential range of the positive electrode plate 11, such as aluminum or aluminum alloy, or a film with the metal disposed on the surface. Preferably, the positive electrode binder layer 33 contains a positive electrode active material, a conductive agent such as acetylene black, and a binder such as polyvinylidene fluoride (PVdF), and is formed on both sides of the positive electrode core 30. The thickness of the positive electrode binder layer 33 is, for example, 40 μm or more and 100 μm or less. The positive electrode active material is, for example, a lithium transition metal composite oxide containing Ni, Co, Mn, Al, etc.

[0028] The negative electrode plate 12 has a negative electrode core 40 and negative electrode binder layers 41 formed on both sides of the negative electrode core 40. The negative electrode core 40 can be a foil of a metal stable within the potential range of the negative electrode plate 12, such as copper or a copper alloy, or a film with the metal disposed on its surface. The negative electrode binder layer 41 contains a negative electrode active material and a binder such as styrene-butadiene rubber (SBR). The thickness of the negative electrode binder layer 41 is, for example, 40 μm or more and 100 μm or less. The negative electrode active material can be, for example, graphite or a Si-containing material.

[0029] A gasket 28 is provided between the metal can 16 and the sealing body 17 to seal the inside of the battery. The metal can 16, for example, has a groove 22 formed by stamping the side portion from the outside to support the sealing body 17. The groove 22 is preferably formed in a ring shape along the circumference of the metal can 16, and supports the sealing body 17 on its upper surface. In addition, the upper end of the metal can 16 is bent inward and hemmed tightly to the periphery of the sealing body 17. Therefore, the sealing body 17 blocks the opening 16a of the metal can 16.

[0030] The sealing body 17 is made of metal and is cap-shaped. It has a cylindrical portion 20 at the center of the circular plate portion 18, bulging upwards and blocked at its upper end by the electrode terminal 19. The upper current collector 50 is electrically connected to the lower surface of the circular plate portion 18 via the conductive member 60 (described later). Thus, the electrode terminal 19 of the sealing body 17 becomes a positive terminal exposed to the outside. It should be noted that by forming a thin-walled portion in the shape of a ring or a C on the lower or upper surface of the electrode terminal 19, a fracture-prone portion that is easily broken due to an increase in the internal pressure of the battery can be formed. In this case, if the internal pressure of the battery increases, the fracture of the fracture-prone portion causes deformation of the inner side of the fracture-prone portion, pushing it upwards, allowing the high-temperature and high-pressure gas inside the battery to be discharged through the opening formed on the inner side.

[0031] At the upper end of the metal can 16, a negative electrode external terminal 70 is fitted and connected around the entire circumference of the outer surface of the bent portion 16b, which bends from the outer peripheral end of the upper surface of the inner portion of the groove 22 upwards. The negative electrode external terminal 70 is made of metal and is formed as a component with a generally L-shaped cross-section having a cylindrical portion 71 and a flange-shaped circular plate portion 72 provided at the upper end of the cylindrical portion 71. The lower end of the cylindrical portion 71 is locked to the outer peripheral end of the upper surface of the inner portion of the groove by a locking portion protruding inwards. The lower surface of the circular plate portion 72 may also contact and be welded to the upper surface of the outer surface of the bent portion 16b of the metal can 16, which is the entire circumference of the metal can 16. An outer insulating member 74 is disposed between the upper surface of the circular plate portion 18 of the sealing body 17 and the outer peripheral surface of the cylindrical portion 20 and the negative electrode external terminal 70 to achieve insulation between the sealing body 17 and the negative electrode external terminal 70. Therefore, a negative electrode external terminal 70 is arranged around the cylindrical portion 20 of the sealing body 17 at the upper part of the cylindrical secondary battery 10. An external negative electrode lead (not shown) is soldered to the negative electrode external terminal 70. An external positive electrode lead (not shown) is soldered to the upper end of the sealing body 17. Thus, electrical components for extracting power can be connected to both the positive and negative electrodes from the upper side of the cylindrical secondary battery 10.

[0032] Furthermore, inside the metal can 16, an insulating member 90 made of an insulating material such as resin is disposed between the upper end of the electrode assembly 14 and the upper current collector 50 and the metal can 16. The insulating member 90 has the function of insulating the upper end of the electrode assembly 14 from the upper current collector 50 and the metal can 16, and also has the function of supporting the downward deformation of the conductive member 60 described later.

[0033] The inner circumferential circular plate portion 91 and the outer circumferential circular plate portion 93 of the insulating member 90 are connected by an inclined cylindrical portion 94. The inner circumferential circular plate portion 91 is positioned higher than the outer circumferential circular plate portion 93. The outer circumferential circular plate portion 93 is mounted on the upper end of the electrode assembly 14 and positioned between the electrode assembly 14 and the lower end of the groove 22 of the metal can 16. The inner circumferential circular plate portion 91 is mounted on the upper end of the outer circumferential portion of the upper current collector 50, and its inner circumferential end faces the lower side of the electrode assembly side, which is the outermost circumference of the conducting member 60 described later. An annular protrusion 92 is formed on the inner circumferential end of the inner circumferential circular plate portion 91, and the annular protrusion 92 has a rectangular cross-section that protrudes upward continuously around the entire circumference. The upper end of the annular protrusion 92 contacts the lower surface of the outermost circumference of the conducting member 60. The function of the insulating member 90 as a support member will be described in detail later.

[0034] The following uses Figure 1 and Figure 2 , Figure 3 The structure of the conductive component 60 is described in detail. Figure 2 This is a three-dimensional view obtained by removing the conductive component 60 from the cylindrical secondary battery 10 and observing it from an obliquely upward side. Figure 3 This is a cross-sectional view of the conductive component 60 (AA section). Figure 4 This is a diagram obtained by observing the conductive component 60 from above.

[0035] As described above, the conductive member 60 is electrically connected to the upper current collector 50 and the sealing body 17. Therefore, the lower end face of the conductive member 60 is connected to the upper surface of the upper current collector 50 by welding. In addition, the upper end face of the conductive member 60 is welded to the lower surface of the circular plate portion 18 of the sealing body 17 after being pressed against it.

[0036] The conductive component 60 is made of a metal plate and has an annular central side plate portion 61 disposed at the radially inner end, and a plurality of inclined portions 62 extending radially from multiple circumferential positions on the outer periphery of the central side plate portion 61 and extending in an inclined direction outwards towards the upper side corresponding to the upper end side of the cylindrical secondary battery 10. Figure 2In this embodiment, the conductive component 60 has four inclined portions 62, but it is not limited to this; as long as there are multiple inclined portions, two, three, or five or more inclined portions can be provided. The conductive component 60 is formed, for example, by stamping a metal sheet such as nickel or nickel-plated steel sheet. The conductive component 60 can also be formed of a conductive metal such as copper or aluminum.

[0037] Furthermore, each inclined portion 62 is connected only via a flat central side plate portion 61. The circumferential sides of each inclined portion 62 are not connected to each other via inclined plate portions that are inclined relative to the central axis O1 in the vertical direction. As a result, each inclined portion 62 can move during the aforementioned pressing without being affected by the movement of other inclined portions. Therefore, it is easy to absorb the circumferential height deviation between the lower surface of the circular plate portion 18 of the sealing body 17 and the upper surface of the upper current collector 50.

[0038] Furthermore, the conductive member 60 has an outer peripheral side plate portion 64 disposed on the outer periphery and connected to the outer peripheral side ends of each inclined portion 62. The outer peripheral side plate portion 64 is arc-shaped, and multiple outer peripheral side plate portions 64 are arranged such that they are located on the same circle and are separated from each other in the circumferential direction. The circumferential width of the outer peripheral side plate portion 64 is larger than the circumferential width of the inclined portion 62. The upper side surface of one side of the outer peripheral side plate portion 64 is connected to the lower surface of the circular plate portion 18 of the sealing body 17. Since the circumferential width of the outer peripheral side plate portion 64 is larger than the circumferential width of the inclined portion 62, even when the distance in the height direction between the lower surface of the circular plate portion 18 of the sealing body 17 and the upper surface of the upper current collector 50 varies in the circumferential direction, it is easier to make the conductive member 60 contact the circular plate portion 18 in a large area of ​​the outer peripheral side plate portion 64.

[0039] The central side plate portion 61 is plate-shaped along a plane orthogonal to the central axis O1, which runs vertically along the conductive member 60. Furthermore, as... Figure 3 As shown, in each inclined portion 62 of the conductive member 60, grooves 66 and 67 are formed on the lower side at both radial ends. The cross-sectional shape of the grooves 66 and 67 is approximately semi-circular, but not limited to this; they can also be V-shaped or rectangular valley-shaped, etc. The grooves are not limited to this either; they can be the same as the upper side, or the upper and lower sides can be different.

[0040] The lower groove 66 is formed in the inclined portion 62 on the lower side of the connecting portion connected to the central side plate portion 61, and extends to both circumferential ends of the inclined portion 62. Through this groove 66, the thin-walled portion 68 extends to both circumferential ends of the inclined portion 62, and its thickness is smaller than the thickness of the portions adjacent to it on both sides. The thin-walled portion 68 corresponds to the first thin-walled portion. As a result, the inclined portion 62 can easily bend upward and downward relative to the central side plate portion 61, and the outer peripheral side plate portion 64 can easily move in the vertical direction. Therefore, the outer peripheral side plate portions 64 of the conductive member 60 can easily absorb the circumferential height deviation between the sealing body 17 and the upper current collector 50.

[0041] The upper groove 67 is formed in the inclined portion 62 on the lower side of the connecting portion connected to the outer peripheral side plate portion 64, and extends to both circumferential ends of the inclined portion 62. Through this groove 67, the thin-walled portion 69 extends to both circumferential ends of the inclined portion 62, and its thickness is smaller than the thickness of the portions adjacent to it on both sides. The thin-walled portion 69 corresponds to the second thin-walled portion. As a result, the outer peripheral side plate portion 64 can easily bend upward and downward about the upper end of the inclined portion 62. Therefore, by contacting the upper end of the annular protrusion 92 of the insulating member 90 with the lower surface of the outer peripheral side plate portion 64, the upper surface of the outer peripheral side plate portion 64 can easily make surface contact with the lower surface of the circular plate portion 18 of the sealing body 17 by utilizing the synergistic effect with suppressing the downward deformation of the conductive member 60. Therefore, it is possible to effectively prevent the upper corner of the outer peripheral side plate portion 64 from making angular contact with the lower surface of the circular plate portion 18, which would lead to poor welding. It should be noted that, without making the insulating member 90 contact the lower surface of the outer peripheral side plate portion 64, it is also possible to configure it so that the upper groove portion 67 and the upper thin-walled portion 69 are not formed.

[0042] Furthermore, the radial sides S1 and S2 and the circumferential sides S3 and S4 of the four outer peripheral side plates 64 do not contact other components. The four outer peripheral side plates 64 are independently separated from each other. Thus, as will be described later, after the lower surface of the center side plate 61 of the conductive member 60 is welded to the upper surface of the upper current collector 50, when the sealing body 17, which is hemmed and fixed to the upper end of the metal can 16, is pressed from above to press the sealing body 17 into the conductive member 60, the outer peripheral side plates 64 are allowed to move radially and circumferentially. Therefore, while bending the inclined portion 62, each outer peripheral side plate 64 is moved as follows: Figure 1 As shown by the arrow, it moves radially, making it easier to absorb the circumferential height deviation between the upper current collector 50 and the sealing body 17 using the conductive component 60.

[0043] In addition, such as Figure 4As shown, when the conductive member 60 is viewed from the vertical direction on one side of the central axis O1, the valley lines of the groove 66 of the thin-walled portion 68 forming the conductive member 60 are straight. Therefore, unlike the case where each valley line is set to an arc shape along the shape of the connection between the inclined portion 62 and the central side plate portion 61, the inclined portion 62 is more flexible than the central side plate portion 61.

[0044] Furthermore, when viewing the conductive member 60 from one side in the vertical direction, the valley lines of the groove 67 forming the thin-walled portion 69 of the conductive member 60 are straight. Therefore, unlike the case where each valley line is arc-shaped along the shape of the connection between the inclined portion 62 and the outer peripheral side plate portion 64, the outer peripheral side plate portion 64 is more flexible than the inclined portion 62. It should be noted that the grooves 66 and 67 can also be configured such that the valley lines are arc-shaped.

[0045] When manufacturing the cylindrical secondary battery 10 described above, after welding the lower current collector 52 to the upper surface of the bottom of the metal can 16, the electrode assembly 14 and the upper current collector 50 on its upper side are housed inside the metal can 16.

[0046] Next, after sequentially placing the insulating member 90 and the center side plate portion 61 of the conductive member 60 on the upper surface of the upper current collector 50, a non-aqueous electrolyte is injected through the upper opening at the upper end of the metal can 16 before bending and tightening. At this time, the center side plate portion 61 of the conductive member 60 can also be pre-welded to the upper surface of the upper current collector 50. Then, the sealing body 17 is tightened and fixed to the upper end of the metal can 16. In this state, the upper end of the annular protrusion 92 of the insulating member 90 is separated from the lower surface of the outer peripheral side plate portion 64 of the conductive member 60 in the vertical direction. Furthermore, the upper surface of the outer peripheral side plate portion 64 is separated from the lower surface of the circular plate portion 18 of the sealing body 17 in the vertical direction. In this state, the groove inlet 22 is... Figure 1 The state shown extends further upwards and downwards.

[0047] Then, pressure is applied to the upper ends of the sealing body 17 and the metal can 16 from above, and the circular plate portion 18 of the sealing body 17 is pressed against the outer peripheral side plate portions 64 of the conductive member 60 while deforming the groove inlet portion 22. At this time, the conductive member 60 is prone to bending at the thin-walled portion 68 on the lower side of each inclined portion 62. Furthermore, other components do not contact the circumferential and radial sides of the outer peripheral side plate portions 64, so circumferential and radial movement of the outer peripheral side plate portions 64 is permitted. Therefore, each outer peripheral side plate portion 64 is not restricted by the movement of other outer peripheral side plate portions 64 and can easily move in the vertical direction. Therefore, the circumferential height deviation between the upper current collector 50 and the sealing body 17 is easily absorbed by the conductive member 60. Therefore, when the conductive member 60 is pressed against the sealing body 17, it is possible to suppress the application of excessive load to the electrode group 14 from the circumferential portion of the upper current collector 50.

[0048] After the conductive component 60 and the sealing body 17 are crimped together, a welding current is passed between the positive and negative terminals of the cylindrical secondary battery 10, thereby welding the conductive component 60 to the sealing body 17, the negative electrode core 40 of the electrode assembly 14 to the lower current collector 52, and the upper lead-out portion 31 of the electrode assembly 14 to the upper current collector 50. At this time, the upper current collector 50 can also be welded to the center side plate portion 61 of the conductive component 60.

[0049] At this time, a radial gap is formed between the radially outer side surface S1 of the outer peripheral side plate portion 64 of the conductive member 60 and the gasket 28, and gaps are also formed on the circumferential outer sides of both circumferential side surfaces of each outer peripheral side plate portion 64. As a result, vapor generated by the heat during welding can easily escape into these gaps. Therefore, it is possible to effectively prevent the formation of holes in the sealing body 17 due to vapor.

[0050] It should be noted that, even after the cylindrical secondary battery 10 is completed, a radial gap may not be formed between the radially outer side surface S1 of the outer peripheral side plate portion 64 of the conductive member 60 and the gasket 28, and the radially outer side surface S1 may contact the gasket 28. In this case, by forming a gap on the circumferentially outer side of each outer peripheral side plate portion 64, the aforementioned vapor can easily escape into this gap. In this case, although... Figure 1 The effect is lower compared to the previous method, but it can still effectively prevent the formation of holes in the sealing body 17 due to steam.

[0051] In addition, after the above-mentioned welding of the cylindrical secondary battery 10, the outer insulating component 74 and the negative electrode side external terminal 70 are fixed to the upper part of the metal can 16.

[0052] It should be noted that, in the above description, the case where the outer peripheral side plate portion 64 is arc-shaped and its circumferential width is larger than that of the inclined portion 62 has been described. However, as long as the outer peripheral side plate portion is connected to the outer peripheral end of each inclined portion 62 and its upper side is connected to the lower surface of the sealing body 17, it can also be a plate with the same circumferential width as the inclined portion 62 and extending radially.

[0053] Figure 5 This is a perspective view of a cylindrical secondary battery in another embodiment, showing the conductive member 60a removed and viewed from an obliquely upward side. In the conductive member 60a of this example, a plurality of inclined portions 80 connecting the central side plate portion 61 and the outer peripheral side plate portion 64 are inclined in a curved manner from multiple circumferential positions on the outer periphery of the central side plate portion 61 toward one side in the circumferential direction, and extend toward the outer peripheral side in the inclined direction upward. In addition, by forming grooves at the upper and lower ends of the lower surface of each inclined portion 80, thin-walled portions 81 and 82 are formed at the upper and lower ends of each inclined portion.

[0054] According to the configuration in this example, the length ratio of each inclined portion 80 can be increased without increasing the outer diameter of the conducting member 60a. Figures 1-4 The structure is large. Therefore, it is easier to deform each inclined part 80 with less force, and thus it is easier to use the conductive member 60a to absorb the circumferential height deviation between the upper current collector 50 and the sealing body 17. In this example, other structures and functions are similar to... Figures 1-4 The configuration is the same. It should be noted that in this example, each inclined portion can also be configured to be inclined in a "straight line" from multiple circumferential positions on the outer periphery of the central side plate portion 61 toward one side in the circumferential direction, and extend toward the outer periphery in the upward inclined direction.

[0055] Furthermore, in the above-described embodiments, the grooves provided at both the upper and lower ends of each inclined portion 62, 80 are described as being located on the lower surface of each inclined portion 62, 80. However, each groove may also be located on the upper surface of each inclined portion. On the other hand, considering that it is easier to bend the inclined portions 62, 80 and the outer peripheral side plate portion 64 more upwards relative to the central side plate portion 61 and the inclined portions 62, 80 with less force, it is preferable to provide grooves on the lower surface of the inclined portions 62, 80 as in the above-described embodiments. Additionally, the grooves may also be configured to form thin-walled portions by being formed on both the upper and lower surfaces of each inclined portion 62, 80.

[0056] Furthermore, in the above embodiment, the case where the sealing body 17 is formed by a single component has been described, but the sealing body may also be formed by combining multiple components. Additionally, in the above embodiment, the case where the insulating component 90 functions as a support member has been described, but a resin component different from the insulating component may also be used as a support member and disposed between the upper current collector 50 and the outer peripheral side plate portion 64 of the conducting components 60, 60a.

[0057] This disclosure is further illustrated by the following embodiments.

[0058] Configuration 1: A cylindrical secondary battery, comprising:

[0059] The electrode assembly is formed by winding the positive and negative electrode plates together with a diaphragm in between;

[0060] A cylindrical metal can with an opening at one end and housing the aforementioned electrode assembly;

[0061] A current collector, which is connected to the electrode assembly inside the aforementioned metal can;

[0062] A sealing body having externally exposed electrode terminals and blocking the aforementioned opening; and

[0063] A conductive component, located inside the metal can, is connected to the current collector and the sealing body.

[0064] The aforementioned conductive component has:

[0065] The central side plate portion along a plane orthogonal to the central axis;

[0066] An inclined portion extends outward in an inclined direction from multiple circumferential locations on the outer periphery of the aforementioned central side plate portion; and

[0067] The outer peripheral side plate is connected to the outer peripheral side ends of each of the aforementioned inclined portions, and one side is connected to the aforementioned sealing body.

[0068] In each of the aforementioned inclined portions, a first thin-walled portion is formed at the connection portion connected to the aforementioned central side plate portion. The first thin-walled portion extends to both circumferential ends of the aforementioned inclined portion and has a thickness smaller than that of the adjacent portions on both sides.

[0069] Configuration 2: The cylindrical secondary battery described in Configuration 1, wherein,

[0070] The circumferential width of the outer peripheral side plate is greater than the circumferential width of the inclined portion.

[0071] Configuration 3: The cylindrical secondary battery according to claim 2, wherein,

[0072] The radial and circumferential sides of the aforementioned outer peripheral side plate do not contact other components.

[0073] Configuration 4: A cylindrical secondary battery according to any one of Configurations 1 to 3, wherein,

[0074] When the conductive member is viewed from one side in the direction of the central axis, the valley line of the first thin-walled portion forming the conductive member is straight.

[0075] Configuration 5: A cylindrical secondary battery according to any one of configurations 1 to 4, comprising a resin support member, the resin support member being mounted on the sealing body side of the current collector in a manner opposite to the electrode group side of the outermost periphery of the conductive member.

[0076] Configuration 6: The cylindrical secondary battery described in Configuration 5, wherein,

[0077] In each of the aforementioned inclined portions, a second thin-walled portion is formed at the connection portion connected to the aforementioned outer peripheral side plate portion. The second thin-walled portion extends to both circumferential ends of the aforementioned inclined portion and has a thickness smaller than the adjacent portions on both sides.

[0078] Explanation of reference numerals in the attached figures

[0079] 10 Cylindrical secondary battery, 11 Positive plate, 12 Negative plate, 13 Separator, 14 Electrode assembly, 16 Metal can, 16a Opening, 16b Bending section, 17 Sealing body, 18 Circular plate section, 19 Top plate section, 20 Cylindrical section, 22 Inlet section, 28 Gasket, 30 Positive electrode core, 31 Upper outlet section, 33 Positive electrode binder layer, 40 Negative electrode core, 41 Negative electrode binder layer, 50 Upper current collector, 52 Lower current collector, 53 Circular plate section, 54 Lower cylindrical section, 60, 60a Conducting component, 61 Center side plate section, 62 Inclined section, 64 Outer peripheral side plate section, 66, 67 Inlet section, 68, 69 Thin-walled section, 70 Negative side external terminal, 71 Cylindrical section, 72 Circular plate portion, 74 outer insulating component, 80 inclined portion, 81, 82 thin-walled portion, 90 insulating component, 92 annular protrusion.

Claims

1. A cylindrical secondary battery, comprising: The electrode assembly is formed by winding the positive and negative electrode plates together with a diaphragm in between; A cylindrical metal can, with an opening at one end and housing the electrode assembly; A current collector component, which is connected to the electrode assembly inside the metal can; A sealing body having externally exposed electrode terminals and blocking the opening; and A conductive component, which is connected inside the metal can to the current collecting component and the sealing body. The conductive component has: The central side plate portion along a plane orthogonal to the central axis; An inclined portion extends from multiple circumferential locations on the outer periphery of the central side plate portion toward the outer periphery in an inclined direction; and The outer peripheral side plate is connected to the outer peripheral side ends of each of the plurality of inclined portions and has one side connected to the sealing body. In each of the plurality of inclined portions, a first thin-walled portion is formed at the connection portion connected to the central side plate portion. The first thin-walled portion extends to both circumferential ends of the inclined portion and has a thickness smaller than that of the adjacent portions on both sides.

2. The cylindrical secondary battery according to claim 1, wherein, The circumferential width of the outer peripheral side plate is greater than the circumferential width of the inclined portion.

3. The cylindrical secondary battery according to claim 2, wherein, The radial and circumferential sides of the outer peripheral side plate do not contact other components.

4. The cylindrical secondary battery according to claim 1, wherein, When the conductive member is viewed from one side in the direction of the central axis, the valley line of the first thin-walled portion forming the conductive member is straight.

5. The cylindrical secondary battery according to claim 1, comprising a resin support member, the resin support member being mounted on the sealing body side of the current collector in a manner opposite to the electrode group side of the outermost periphery of the conductive member.

6. The cylindrical secondary battery according to claim 5, wherein, In each of the plurality of inclined portions, a second thin-walled portion is formed at the connection portion connected to the outer peripheral side plate portion. The second thin-walled portion extends to both circumferential ends of the inclined portion and has a thickness smaller than the adjacent portions on both sides.

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