Electricity storage device, terminal for electricity storage device, and method for manufacturing electricity storage device

Abstract

The invention relates to a power storage device, a terminal for the power storage device, and a method for manufacturing the power storage device. This electricity storage device is provided with an electrode body, a case, a negative electrode terminal, and a negative electrode collector member. The negative electrode terminal includes a first conductive member and a second conductive member. The first conductive member has a recess in the first surface. The first conductive member has a fastening portion and a metal bonding portion. The second conductive member has a flange portion and a connection portion. The front end of the connecting part is provided with an expanding part. The expanded diameter portion is connected to the negative electrode collector member. A portion of the flange portion is disposed in the recess of the first conductive member. The outer peripheral edge of the first conductive member and the outer peripheral edge of the flange portion are at substantially the same position in the radial direction of the flange portion.

Description

Technical Field

[0001] The present invention relates to an electricity storage device, a terminal for an electricity storage device, and a method for manufacturing the electricity storage device. Background Art

[0002] Japanese Patent Application Publication No. 2022-049726 discloses a terminal including a plate-shaped first metal component and a metal second component ultrasonically welded to one surface of the first component. A recess is formed on the surface of the first component opposite to the surface to which the second component is welded. The first component and the second component are ultrasonically welded in the recess.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2022-049726 Summary of the invention

[0004] The present inventors have considered trying to further improve the reliability of the connection portion between the components in a terminal for a power storage device to which a plurality of components are connected.

[0005] The power storage device disclosed herein comprises an electrode body, a housing for accommodating the electrode body, a terminal and a current collecting component. The electrode body comprises a first electrode and a second electrode having a polarity different from that of the first electrode. The housing accommodates the electrode body. The terminal is electrically connected to the first electrode and mounted on the housing. The current collecting component is arranged in the housing and electrically connects the first electrode to the terminal. The terminal comprises a first conductive component composed of a first metal and a second conductive component composed of a second metal different from the first metal. The first conductive component has a recess on the first surface. A portion of the second conductive component is arranged in the recess. The first conductive component has a fastening portion mechanically fastened to the second conductive component and a metal joint portion metal-joined to the second conductive component. In the first conductive component, the fastening portion is located at a position closer to the outer peripheral side than the metal joint portion. The second conductive component has a flange portion and a connecting portion formed on one surface of the flange portion. The front end of the connecting portion has an enlarged diameter portion. The enlarged diameter portion is connected to the current collecting component. A portion of the flange portion is arranged in the recess. The outer peripheral edge of the first conductive member and the outer peripheral edge of the flange portion are located at substantially the same position in the radial direction of the flange portion.

[0006] This power storage device is a power storage device in which the reliability of the connection portion between the first conductive member and the second conductive member is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a perspective view of the power storage device 100 .

[0008] Figure 2 It is along Figure 1 A schematic longitudinal cross-sectional view taken along line II-II.

[0009] Figure 3It is a cross-sectional view showing the negative electrode terminal 40 attached to the sealing plate 24 .

[0010] Figure 4 It is a perspective view showing the battery pack 200 .

[0011] Figure 5 It is a cross-sectional view showing the first conductive member 41 and the second conductive member 42 before being fastened in the fastening step.

[0012] Figure 6 It is a cross-sectional view showing the first conductive member 41 and the second conductive member 42 after being fastened in the fastening step.

[0013] Figure 7 It is a schematic diagram showing the riveting process.

[0014] Figure 8 It is a cross-sectional view of a negative electrode terminal 140 according to another embodiment. DETAILED DESCRIPTION

[0015] Hereinafter, an embodiment of the technology disclosed herein will be described with reference to the accompanying drawings. The embodiments described here are of course not intended to specifically limit the present invention. The drawings are schematically depicted and do not necessarily reflect the actual objects. In addition, the same figure marks are appropriately marked for components and parts that play the same role, and repeated descriptions are appropriately omitted. In the following description, the figure marks L, R, F, Rr, U, and D in the drawings represent left, right, front, back, top, and bottom, and the figure marks X, Y, and Z in the drawings represent the long side direction, short side direction, and height direction of the power storage device, respectively. However, these are just directions for the convenience of description and do not limit the setting form of the power storage device in any way.

[0016] In addition, in this specification, "power storage device" refers to all power storage devices that can extract electrical energy. In addition to secondary batteries that can be repeatedly charged and discharged by moving charge carriers between a pair of electrodes (positive and negative electrodes) via electrolytes, power storage devices also include capacitors such as double-layer capacitors. Below, the manufacturing method of the power storage device is described for the case where a lithium-ion secondary battery is used as the object.

[0017] <Electricity Storage Device 100>

[0018] Figure 1 It is a perspective view of the power storage device 100 . Figure 2 It is along Figure 1 A schematic longitudinal cross-sectional view of line II-II. Figure 2 In the figure, the gasket 50 and the insulator 60 are omitted. Figure 3 It is a cross-sectional view showing the negative electrode terminal 40 attached to the sealing plate 24 . Figure 42 is a perspective view showing the battery pack 200. Figure 4 , a mode in which the power storage device 100 disclosed here is used as a single cell and a plurality of power storage devices 100 are connected in series via a bus bar 90 is illustrated.

[0019] like Figure 2 As shown, the power storage device 100 includes an electrode body 10, a housing 20, a positive terminal 30, a negative terminal 40, a positive electrode collector component 13, and a negative electrode collector component 14. The power storage device 100 may also include an external conductive component 48. The power storage device 100 is characterized by having the positive terminal 30 and / or the negative terminal 40 disclosed herein, and the structure other than that may be the same as before. The power storage device 100 is preferably a secondary battery, and more preferably a non-aqueous electrolyte secondary battery. Here, the power storage device 100 is a lithium ion secondary battery. Although not shown in the figure, the power storage device 100 also includes an electrolyte. The power storage device 100 is constructed by accommodating the electrode body 10 and the electrolyte not shown in the figure in the housing 20.

[0020] The electrode body 10 may be the same as in the past and is not particularly limited. The electrode body 10 includes a positive electrode and a negative electrode (not shown). The electrode body 10 is, for example, a flat wound electrode body in which a strip-shaped positive electrode and a strip-shaped negative electrode are stacked in an insulated state with a strip-shaped separator interposed therebetween and wound around a winding axis. However, in other embodiments, the electrode body 10 may also be a stacked electrode body in which a square (typically rectangular) positive electrode and a square (typically rectangular) negative electrode are stacked in an insulated state. One of the positive electrode and the negative electrode is an example of a "first electrode", and the other is an example of a "second electrode".

[0021] The positive electrode has a positive electrode collector 11 and a positive electrode mixture layer (not shown) fixed on the positive electrode collector 11. The positive electrode collector 11 is composed of, for example, a conductive metal such as aluminum, an aluminum alloy, nickel, and stainless steel. The positive electrode mixture layer contains a positive electrode active material (for example, a lithium transition metal composite oxide). The negative electrode has a negative electrode collector 12 and a negative electrode mixture layer (not shown) fixed on the negative electrode collector 12. The negative electrode collector is composed of, for example, a conductive metal such as copper, a copper alloy, nickel, and stainless steel. The negative electrode mixture layer contains a negative electrode active material (for example, a carbon material such as graphite).

[0022] As in Figure 2As indicated by the oblique lines in the figure, in the central part of the long side direction X of the electrode body 10, there is formed a stacked portion in which the positive electrode mixture layer and the negative electrode mixture layer are stacked in an insulated state. On the other hand, at the left end part of the long side direction X of the electrode body 10, a part of the positive electrode collector 11 (the positive electrode collector exposed portion) on which the positive electrode mixture layer is not formed extends from the stacked portion. A positive electrode collector component 13 is attached to the positive electrode collector exposed portion. The positive electrode collector component 13 can also be made of the same metal material as the positive electrode collector 11, such as conductive metals such as aluminum, aluminum alloy, nickel, and stainless steel. The positive electrode collector component 13 is arranged in the outer casing 20. The positive electrode collector component 13 electrically connects the positive electrode to the positive terminal 30.

[0023] In addition, at the right end of the electrode body 10 in the long side direction X, a part of the negative electrode collector 12 (the exposed part of the negative electrode collector) where the negative electrode mixture layer is not formed extends from the stacked part. A negative electrode collector component 14 is attached to the exposed part of the negative electrode collector. The material (metal type) of the negative electrode collector component 14 can be different from that of the positive electrode collector component 13. The negative electrode collector component 14 can also be composed of the same metal type as the negative electrode collector 12, such as conductive metals such as copper, copper alloy, nickel, and stainless steel. The negative electrode collector component 14 is arranged in the outer shell 20. The negative electrode collector component 14 electrically connects the negative electrode to the negative terminal 40. The negative electrode collector component 14 electrically connects the negative electrode to the negative terminal 40 inside the outer shell 20.

[0024] The electrolyte can be the same as before and is not particularly limited. The electrolyte is, for example, a non-aqueous liquid electrolyte (non-aqueous electrolyte) containing a non-aqueous solvent and a supporting salt. The non-aqueous solvent includes, for example, carbonates such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. The supporting salt is, for example, LiPF 6 However, the electrolyte may be integrated with the electrode body 10 in a solid state (solid electrolyte).

[0025] The outer shell 20 is a shell that contains the electrode body 10. Here, the outer shell 20 is formed into a flat and bottomed cubic shape (square). However, the shape of the outer shell 20 is not limited to a square, and can be any shape such as a cylinder. The material of the outer shell 20 can be the same as the material used in the past, and there is no special restriction. The outer shell 20 is made of a light metal material with good thermal conductivity, such as aluminum, aluminum alloy, and stainless steel. The outer shell 20 includes an outer body 22 having an opening 22h, and a sealing plate 24 that blocks the opening 22h. Preferably, the outer shell 20 includes an outer body 22 and a sealing plate 24. The outer shell 20 is integrated by joining (for example, welding) the sealing plate 24 to the periphery of the opening 22h of the outer body 22. The outer shell 20 is hermetically sealed (sealed).

[0026] The outer body 22 has a bottom surface 22d. The sealing plate 24 is opposite to the bottom surface 22d of the outer body 22. The sealing plate 24 is installed on the outer body 22 in a manner to block the opening 22h of the outer body 22. Here, the sealing plate 24 is roughly rectangular. In addition, in this specification, "roughly rectangular" is a term other than a complete rectangular shape (rectangle), for example, including a shape in which the corner connecting the long side and the short side of the rectangle is R-shaped, a shape with a cutout at the corner, etc.

[0027] The positive terminal 30 and the negative terminal 40 protrude to the outside of the outer shell 20. Here, the positive terminal 30 and the negative terminal 40 protrude from the same surface of the outer shell 20 (specifically, the sealing plate 24). However, the positive terminal 30 and the negative terminal 40 may protrude from different surfaces of the outer shell 20. The positive terminal 30 and the negative terminal 40 are respectively arranged at both end portions of the sealing plate 24 in the long side direction X. The positive terminal 30 and / or the negative terminal 40 are an example of a "terminal for a storage device".

[0028] like Figure 2 As shown, the positive terminal 30 is electrically connected to the positive electrode of the electrode body 10 via the positive electrode collector 13 inside the outer shell 20. The negative terminal 40 is electrically connected to the negative electrode of the electrode body 10 via the negative electrode collector 14 inside the outer shell 20. The positive terminal 30 and the negative terminal 40 are respectively mounted on the outer shell 20 (specifically, the sealing plate 24). Preferably, the positive terminal 30 and the negative terminal 40 are fixed to the outer shell 20 (specifically, the sealing plate 24). The positive terminal 30 and the negative terminal 40 are respectively separated by a gasket 50 (refer to Figure 3 ) and insulator 60 (refer to Figure 3 ) is insulated from the sealing plate 24.

[0029] Hereinafter, the structure of the positive terminal 30 and the negative terminal 40 of the power storage device 100 will be described in detail by taking the terminal structure on the side of the negative terminal 40 as an example. The terminal structure described below is preferably provided on the negative terminal 40 side. In addition, the terminal structure described below may be provided on the positive terminal 30 side, or may be provided on both the positive terminal 30 side and the negative terminal 40 side. In this case, in the following description, the part of "negative electrode" can be appropriately replaced with "positive electrode".

[0030] like Figure 3As shown, a terminal mounting hole 24h is formed in the sealing plate 24 and passes through in the up-down direction Z. The terminal mounting hole 24h is provided in the housing 20 (in this embodiment, the sealing plate 24). Preferably, a negative terminal 40 is inserted into the terminal mounting hole 24h. Although not shown in the figure, here, the terminal mounting hole 24h is circular (e.g., a perfect circle) in a top view. The terminal mounting hole 24h has an inner diameter of a size that can be inserted through a connecting portion 42c of the negative terminal 40 described later before riveting. The terminal mounting hole 24h is formed to be smaller than the flange portion 42f of the negative terminal 40 described later.

[0031] The negative electrode current collecting component 14 is attached to the negative electrode current collector exposed portion of the negative electrode current collector 12, and constitutes a conduction path that electrically connects the negative electrode to the negative terminal 40. The negative electrode current collecting component 14 has a flat plate-shaped portion 14f extending horizontally along the inner surface of the sealing plate 24. In the flat plate-shaped portion 14f, an opening 14h is provided at a position corresponding to the terminal mounting hole 24h. The opening 14h has an inner diameter of a size that can be inserted through the connection portion 42c of the negative terminal 40 before riveting, which will be described later. The negative electrode current collecting component 14 is fixed to the sealing plate 24 together with the negative terminal 40 by riveting. It is preferred that an insulating component made of resin is arranged between the housing 20 (in this embodiment, the sealing plate 24) and the negative electrode current collecting component 14. In this embodiment, the negative electrode current collecting component 14 is fixed to the sealing plate 24 together with the negative terminal 40 in an insulated state separated by the insulator 60. The negative electrode current collecting component 14 is an example of a current collecting component.

[0032] The gasket 50 is an insulating member disposed between the upper surface (outer surface) of the sealing plate 24 and the negative terminal 40. An insulating member (e.g., gasket 50) is preferably disposed between the housing 20 (e.g., the sealing plate 24) and the negative terminal 40. Here, the gasket 50 has the function of insulating the sealing plate 24 from the negative terminal 40 and sealing the terminal mounting hole 24h. The gasket 50 is made of an electrically insulating and elastically deformable resin material, such as a fluorinated resin such as a perfluoroalkoxy fluorine resin (PFA), a polyphenylene sulfide resin (PPS), an aliphatic polyamide, and the like.

[0033] The gasket 50 has a barrel 51 and a base 52. The barrel 51 is a part that prevents direct contact between the sealing plate 24 and the connection portion 42c of the negative terminal 40. The barrel 51 is a hollow cylindrical shape. The barrel 51 has a hole 51h that penetrates in the up-down direction Z. The hole 51h is formed so that the connection portion 42c of the negative terminal 40 before the riveting process can be inserted. The barrel 51 is inserted into the terminal mounting hole 24h of the sealing plate 24. The base 52 is a part that prevents direct contact between the sealing plate 24 and the flange portion 42f of the negative terminal 40 described later. The base 52 is connected to the upper end of the barrel 51. The base 52 extends in the horizontal direction from the upper end of the barrel 51. The base 52 is formed in a circular ring shape, for example, in a manner that surrounds the terminal mounting hole 24h of the sealing plate 24. The base 52 extends along the upper surface of the sealing plate 24. The base portion 52 is sandwiched between the lower surface 42 d of the flange portion 42 f of the negative electrode terminal 40 and the upper surface of the sealing plate 24 , and is compressed in the up-down direction Z by caulking.

[0034] The insulator 60 is an insulating component disposed between the lower surface (inner surface) of the sealing plate 24 and the negative electrode current collecting component 14. It is preferred that an insulating component (such as the insulator 60) is disposed between the housing 20 (such as the sealing plate 24) and the negative electrode current collecting component 14. The insulator 60 has a flat plate-shaped portion extending horizontally along the inner surface of the sealing plate 24. In the flat plate-shaped portion, a hole portion 60h is formed at a position corresponding to the terminal mounting hole 24h. The hole portion 60h has an inner diameter of a size that can be inserted through the shaft portion 42s of the negative terminal 40. The insulator 60 is composed of a resin material that has resistance to the electrolyte used and electrical insulation and can be elastically deformed, such as a fluorinated resin such as a perfluoroalkoxy fluorine resin (PFA), a polyphenylene sulfide resin (PPS), etc. The flat plate portion of the insulator 60 is sandwiched between the lower surface of the sealing plate 24 and the upper surface of the negative electrode current collecting component 14, and is compressed in the up and down direction Z by riveting.

[0035] <Negative terminal 40>

[0036] The negative electrode terminal 40 includes a first conductive component 41 and a second conductive component 42. Figure 3 As shown, the negative electrode terminal 40 is inserted through the terminal mounting hole 24h and extends from the inside to the outside of the case 20. The negative electrode terminal 40 may further include an external conductive member 48 connected to the first conductive member 41 outside the case 20.

[0037] As described later, the negative terminal 40 is formed by integrating two conductive members, namely, a first conductive member 41 and a second conductive member 42, through a fastening portion 43 and a metal joint portion 45. The first conductive member 41 and the second conductive member 42 are electrically connected to each other through the fastening portion 43 and the metal joint portion 45.

[0038] The negative terminal 40 is inserted into the terminal mounting hole 24h of the sealing plate 24 and the opening 14h of the negative current collecting component 14, and the front end portion in the insertion direction (the cylindrical portion 42c2 described later) is riveted to the negative current collecting component 14. In detail, it is riveted to the peripheral portion of the negative current collecting component 14 surrounding the opening 14h. A riveted portion 40c is formed at the lower end of the negative terminal 40. The negative terminal 40 is fixed to the sealing plate 24 by riveting and is electrically connected to the negative current collecting component 14. Here, the riveted portion 40c is cylindrical. However, the shape of the riveted portion 40c is not limited to a cylindrical shape, and can also be an arbitrary shape such as a columnar shape. In addition, it is preferred that the riveted portion 40c is welded to the negative current collecting component 14. Below, the first conductive component 41 and the second conductive component 42 constituting the negative terminal 40 are described.

[0039] <First Conductive Member 41 >

[0040] The first conductive component 41 is a component disposed outside the housing 20. The first conductive component 41 is made of a first metal. The first metal is, for example, a conductive metal such as aluminum, an aluminum alloy, nickel, or stainless steel. Preferably, the first metal is aluminum or an aluminum alloy. Here, the first conductive component 41 is made of aluminum. Preferably, the first conductive component 41 is made of a (soft) metal having a Vickers hardness less than that of the second conductive component 42. The first conductive component 41 may also be the same metal as the positive electrode current collecting component 13, or an alloy having the same metal element as the first component (the component having the highest proportion in terms of mass ratio. The same applies hereinafter).

[0041] In this embodiment, the first conductive component 41 is plate-shaped (specifically, a flat plate). The first conductive component 41 is roughly circular in a top view. The first conductive component 41 has a first surface 41a and a second surface 41b. The first surface 41a is a surface joined to the second conductive component 42. The second surface 41b is a surface on the opposite side of the first surface 41a. In this embodiment, an external conductive component 48 is installed on the second surface 41b. Preferably, the external conductive component 48 extends along the long side direction of the sealing plate 24. Preferably, the external conductive component 48 is made of the same type of metal as the first conductive component 41 (in this embodiment, aluminum or aluminum alloy). The external conductive component 48 does not necessarily have to be installed on the second surface 41b. For example, a bus bar 90 (see Figure 4 ) and other external conductive parts. Figure 4 ), the bus bar 90 may be directly connected to the first conductive component 41 .

[0042] The first conductive component 41 has a recess 41r on the first surface 41a. The recess 41r is provided at a substantially central portion of the first conductive component 41 in a plan view. The recess 41r is formed so that the diameter increases from the opening 41r1 toward the bottom 41r2. The side surface of the recess 41r is tapered so that the diameter gradually increases toward the depth direction. A portion of the second conductive component 42 is disposed in the recess 41r. The first conductive component 41 has a fastening portion 43 mechanically fastened to the second conductive component 42, and a metal bonding portion 45 metal-bonded to the second conductive component 42.

[0043] <Second Conductive Member 42 >

[0044] The second conductive component 42 is a component that extends from the inside to the outside of the housing 20 by inserting through the terminal mounting hole 24h. The second conductive component 42 is made of a second metal different from the first metal. The second metal is, for example, a conductive metal such as copper, a copper alloy, nickel, or stainless steel. Preferably, the second metal is made of copper or a copper alloy. Here, the second conductive component 42 is made of copper. Preferably, the second conductive component 42 is made of a (hard) metal having a Vickers hardness greater than that of the first conductive component 41. The second metal may also be the same metal as the negative electrode current collecting component 14, or an alloy having the same metal element as the first component. The second conductive component 42 may also be coated with other metals on a portion or all of its surface by Ni plating, tin plating, or the like.

[0045] The second conductive component 42 has a flange portion 42f and a connecting portion 42c. The flange portion 42f is a portion of the second conductive component 42 that has a larger diameter than other portions in the surface direction (X direction and Y direction). The flange portion 42f is a portion disposed outside the housing 20. The flange portion 42f is connected to the first conductive component 41. The connecting portion 42c is a portion that is inserted through the terminal mounting hole 24h of the housing 20 (in this embodiment, the sealing plate 24) and the opening 14h of the negative electrode current collecting component 14. The base 52 of the gasket 50 is disposed between the flange portion 42f and the sealing plate 24. The barrel 51 of the gasket 50 is disposed between the connecting portion 42c and the sealing plate 24.

[0046] The flange portion 42f has an outer diameter shape corresponding to the planar shape of the first conductive component 41. The outer peripheral edge 41o of the first conductive component 41 and the outer peripheral edge 42fo of the flange portion 42f are at approximately the same position in the radial direction of the flange portion 42f. For example, in the radial direction of the flange portion 42f, the outer peripheral edge 41o of the first conductive component 41 and the outer peripheral edge 42fo of the flange portion 42f may extend relative to the other by a dimension within 2 mm. The smaller the dimension of the extension of one side relative to the other, the more preferred, more preferably within 1 mm, and further preferably within 0.5 mm. In this embodiment, the flange portion 42f is roughly disc-shaped with a size approximately the same as the size of the first surface 41a of the first conductive component 41. When the outer peripheral edge 41o of the first conductive component 41 and the outer peripheral edge 42fo of the flange portion 42f are in approximately the same position in the radial direction of the flange portion 42f, when the negative terminal 40 is observed from the radial direction of the flange portion 42f, the boundary between the outer peripheral edge 41o of the first conductive component 41 and the outer peripheral edge 42fo of the flange portion 42f can be confirmed along the circumferential direction.

[0047] The flange portion 42f has a protrusion 42p and a reduced diameter portion 42n. The protrusion 42p is formed on the upper surface 42u of the flange portion 42f. The protrusion 42p has a shape along the recess 41r. The diameter of the protrusion 42p increases as it moves toward the front end side (the side away from the flange portion 42f). The diameter of the protrusion 42p decreases as it moves from the front end toward the base end. The reduced diameter portion 42n is a portion where a portion of the side surface of the protrusion 42p is reduced in diameter. The reduced diameter portion 42n is a portion that is smaller in diameter and concave compared to other portions of the protrusion 42p. In this embodiment, the reduced diameter portion 42n is formed at the base end of the protrusion 42p.

[0048] A portion of the flange portion 42f (in this embodiment, the protrusion 42p) is disposed in the recess 41r of the first conductive member 41. The first conductive member 41 is connected to the second conductive member 42 by a mechanically fastened fastening portion 43. For example, the form of the fastening portion 43 is not particularly limited as long as it is a mechanical fastening based on mechanical energy. The fastening portion 43 may be a portion fastened by, for example, press-fitting, shrink fitting, riveting, rivet, folding, bolting, etc.

[0049] Preferably, the fastening portion 43 is provided with a recessed portion on the outer peripheral side wall of the flange portion 42f of the second conductive component 42, and a part of the first conductive component 41 is arranged in the recessed portion. In this embodiment, a reduced diameter portion 42n as a recessed portion is provided on the outer peripheral side wall of the flange portion 42f of the second conductive component 42. The fastening portion 43 is realized by the recessed portion 41r of the first conductive component 41 and the protruding portion 42p and the reduced diameter portion 42n of the second conductive component 42. A part of the inner wall of the recessed portion 41r of the first conductive component 41 enters the reduced diameter portion 42n of the second conductive component 42. Thus, the inner wall of the recessed portion 41r of the first conductive component 41 is fixed (for example, pressed and fixed) by the reduced diameter portion 42n of the second conductive component 42. In this way, the protruding portion 42p is fitted into the recessed portion 41r. As a result, the first conductive component 41 and the second conductive component 42 are mechanically fastened. In addition, the first conductive member 41 and the second conductive member 42 are bonded to each other via a metal bonding portion 45 . The metal bonding portion 45 is located on the inner peripheral side of the fastening portion 43 .

[0050] The metal joint 45 is a portion where the first conductive component 41 and the second conductive component 42 are metal-joined to each other. Here, metal joining refers to a portion where a plurality of metal components are joined to each other by metallurgical joining, excluding joining based on mechanical fastening. The metal joint 45 can be formed, for example, by ultrasonic joining, diffusion joining, laser welding, etc. From the viewpoint of suppressing the formation of fragile intermetallic compounds at the joining interface, the metal joint 45 is preferably an ultrasonic joint formed by ultrasonic joining. In this embodiment, the metal joint 45 is an ultrasonic joint where the first conductive component 41 and the second conductive component 42 are joined to each other by ultrasonic joining.

[0051] In addition, as long as it is located on the inner peripheral side of the fastening portion 43, the position of the metal joint 45 is not particularly limited. The first conductive component 41 has a first region A1 and a second region A2. When viewed along the direction in which the connecting portion 42c of the second conductive component 42 described later extends, the first region A1 is a region overlapping the expanded diameter portion 42e. The second region A2 is located at a position closer to the inside than the first region A1. Between the first region A1 and the second region A2, other regions such as regions in which ribs 41ri described later are formed may also be provided. In addition, in this embodiment, the direction in which the connecting portion 42c extends corresponds to the thickness direction of the portion (sealing plate 24) in the housing 20 where the terminal mounting hole 24h for mounting the negative terminal 40 is provided.

[0052] In this embodiment, the edge of the opening 41r1 of the recess 41r is formed at a position outside the first area A1. Therefore, in a top view observed along the direction in which the connecting portion 42c extends, the first area A1 and the second area A2 are located inside the area where the recess 41r is formed. The metal joint 45 is formed in the second area A2. It is preferred that the upper surface of the first area A1 and the upper surface of the second area A2 are substantially the same plane. For example, the difference in height between the upper surface of the first area A1 and the upper surface of the second area A2 is preferably 2 mm or less, more preferably 1 mm or less, and further preferably 0.5 mm or less.

[0053] In the first conductive component 41, the fastening portion 43 is located at a position on the outer peripheral side than the metal joint portion 45. In other words, the fastening portion 43 is located at a position on the outer side than the metal joint portion 45 in the surface direction (X direction and Y direction) of the first conductive component 41. In this embodiment, the metal joint portion 45 is formed at a substantially central portion of the bottom 41r2 of the recessed portion 41r of the first conductive component 41. Since the metal joint portion 45 is formed at a substantially central portion of the interface between the first conductive component 41 and the second conductive component 42, it is not easy to apply the electric current from the power storage device 100 and the bus bar 90 (see Figure 4 ) and other loads caused by vibration.

[0054] The second conductive component 42 has a connecting portion 42c connected to the negative electrode current collecting component 14. The connecting portion 42c is a portion formed on one surface of the flange portion 42f (in this embodiment, the lower surface 42d). The connecting portion 42c is provided on a surface on the opposite side of the surface on which the protrusion 42p is formed. The front end of the connecting portion 42c has an expanded diameter portion 42e. The expanded diameter portion 42e is a portion that expands in diameter toward the front end of the connecting portion 42c. The expanded diameter portion 42e is connected to the negative electrode current collecting component 14. The expanded diameter portion 42e is also referred to as a rivet portion 40c, which is connected by riveting relative to the negative electrode current collecting component 14. From the viewpoint of improving conductivity, it is preferred to join the expanded diameter portion 42e to a portion of the negative electrode current collecting component 14 by laser welding or the like.

[0055] In this embodiment, the connection portion 42c includes a solid portion 42c1 and a cylindrical portion 42c2. The connection portion 42c is a portion constituting the rivet portion 40c of the negative terminal 40 described above. The solid portion 42c1 is a roughly cylindrical portion extending from the lower surface 42d of the flange portion 42f. The solid portion 42c1 extends from the roughly central portion of the lower surface 42d of the flange portion 42f. The solid portion 42c1 extends toward the front end side of the connection portion 42c. The cylindrical portion 42c2 is a roughly cylindrical portion extending from the solid portion 42c1 toward the front end side before being connected to the negative electrode current collecting component 14. The cylindrical portion 42c2 is enlarged in diameter when connected to the negative electrode current collecting component 14, and a portion thereof is riveted to the negative electrode current collecting component 14 as the enlarged diameter portion 42e, and is connected to the negative electrode current collecting component 14.

[0056] In addition, the structure of the connecting portion 42c is not particularly limited. From the viewpoint of easy diameter expansion when connected to the negative electrode current collector 14, the connecting portion 42c preferably has a cylindrical portion 42c2 on the front end side (the side away from the flange portion 42f). In the connecting portion 42c, the solid portion 42c1 may not be provided, and a cylindrical portion 42c2 may extend from the flange portion 42f. However, from the viewpoint of the strength of the connecting portion 42c, it is preferred that a solid portion 42c1 extending from the flange portion 42f is provided in the connecting portion 42c. The solid portion 42c1 can be set to a size corresponding to the thickness of the sealing plate 24, for example.

[0057] In the above-mentioned negative terminal 40, a part of the interface between the first conductive component 41 and the second conductive component 42 is metal-bonded by the metal bonding portion 45. As a result, the resistance between the first conductive component 41 and the second conductive component 42 becomes low. As a result, the conductivity between the first conductive component 41 and the second conductive component 42 is good. The first conductive component 41 and the second conductive component 42 are mechanically fastened by the fastening portion 43 located at a position closer to the outer peripheral side than the metal bonding portion 45. As a result, the first conductive component 41 and the second conductive component 42 are firmly connected. As a result, it is easy to maintain the metal bonding portion 45, and it is easy to maintain good conductivity between the first conductive component 41 and the second conductive component 42.

[0058] In the negative terminal 40 described above, the outer peripheral edge 41o of the first conductive component 41 and the outer peripheral edge 42fo of the flange 42f are at substantially the same position in the radial direction of the flange 42f. In the negative terminal 40 of this structure, the size of the second conductive component 42 can be made the same as the size of the first conductive component 41 in a plan view, and the diameter of the fastening portion 43 provided along the circumferential direction of the flange 42f can be increased. By increasing the diameter of the fastening portion 43, the bonding strength from the fastening portion 43 is increased. As a result, it is easy to maintain the metal joint 45, and it is easier to maintain good conductivity between the first conductive component 41 and the second conductive component 42. In addition, by increasing the ratio of the second conductive component 42 to the negative terminal 40, the conductivity between the first conductive component 41 and the second conductive component 42 can be improved. As a result, the heating caused by power-on is suppressed, and the durability of the power storage device 100 can be improved.

[0059] <Method for Manufacturing Negative Electrode Terminal 40>

[0060] The negative terminal 40 described above can be manufactured, for example, by a method for manufacturing a terminal for a storage device (in this embodiment, the negative terminal 40) described below. The method for manufacturing a terminal for a storage device includes a preparation step of preparing a first conductive component 41 and a second conductive component 42, a fastening step of fastening the first conductive component 41 and the second conductive component 42, and a metal bonding step of metal bonding the first conductive component 41 and the second conductive component 42. The method for manufacturing a terminal for a storage device may also include other steps.

[0061] Figure 5 It is a cross-sectional view showing the first conductive member 41 and the second conductive member 42 before being fastened in the fastening step. Figure 6 4 is a cross-sectional view showing the first conductive member 41 and the second conductive member 42 after being fastened in the fastening step. Figure 6 In FIG. 1 , the shape of the first conductive member 41 before plastic deformation is indicated by a dotted line. Figure 6 In FIG. 1 , the direction in which the first conductive member 41 is plastically deformed is indicated by an arrow.

[0062] In the preparation process, the first conductive component 41 and the second conductive component 42 are prepared. As the second conductive component 42, a second metal of the above-mentioned shape is prepared. In this embodiment, as the first conductive component 41, a metal having a lower rigidity than the second conductive component 42 is used. As the first conductive component 41, a conductive component having a shape that is deformed along the protrusion 42p and the reduced diameter portion 42n of the second conductive component 42 when riveted in the fastening process is prepared. In this embodiment, the first conductive component 41 having a recess 41R and a wall portion 41W is prepared (see Figure 5 ) The recessed portion 41R is a portion that becomes the recessed portion 41r after the second conductive member 42 is housed.

[0063] Here, it is preferred that the outer periphery 41o of the first conductive component 41 and the outer periphery 42fo of the flange 42f are substantially the same shape. It is preferred that the outer periphery 41o of the first conductive component 41 and the outer periphery 42fo of the flange 42f are substantially the same size. The size difference between the outer periphery 41o of the first conductive component 41 and the outer periphery 42fo of the flange 42f is, for example, within 2 mm, preferably within 1 mm, more preferably within 0.5 mm, and further preferably 0 mm.

[0064] The inner diameter of the recess 41R is not particularly limited as long as it is a size that allows the protrusion 42p of the second conductive component 42 to be inserted. In this embodiment, it is substantially the same as the protrusion 42p of the second conductive component 42. The wall 41W is a portion that is pressed by the upper surface 42u of the flange 42f when the protrusion 42p of the second conductive component 42 is inserted into the recess 41R of the first conductive component 41. The height of the wall 41W (the depth of the recess 41R) is set to a size larger than the height of the protrusion 42p.

[0065] In the fastening step, the first conductive member 41 and the second conductive member 42 are mechanically fastened. In this embodiment, the first conductive member 41 and the second conductive member 42 are mechanically fastened by riveting the first conductive member 41 to the second conductive member 42. Figure 5 As shown, the first conductive member 41 before being fastened to the second conductive member 42 has a recessed portion 41R in which the protruding portion 42p of the second conductive member 42 is arranged. The recessed portion 41R is a portion that is recessed in a substantially cylindrical shape along the depth direction.

[0066] In the fastening process, first, the first conductive member 41 is arranged on the mold 70. The dimensions of the inner peripheral surface of the mold 70 correspond to the dimensions of the outer peripheral edge 41o of the first conductive member 41 and the outer peripheral edge 42fo of the flange portion 42f. From the viewpoint of suppressing unnecessary deformation of the first conductive member 41, it is preferred that the mold 70 has a shape that surrounds the entire circumference of the outer peripheral edge 41o of the first conductive member 41.

[0067] Next, the second conductive component 42 is fastened to the first conductive component 41 disposed on the mold 70. In this embodiment, the second conductive component 42 is punched onto the first conductive component 41 in such a manner that the protrusion 42p of the second conductive component 42 is inserted into the recess 41R of the first conductive component 41. At this time, a known punching device (not shown) or the like can be used. During punching, the wall portion 41W of the first conductive component 41 is punched out by the upper surface 42u of the flange portion 42f of the second conductive component 42 by making the wall portion 41W higher than the protrusion 42p. At this time, the first conductive component 41 is flattened and plastically deformed because its rigidity is lower than that of the second conductive component 42.

[0068] like Figure 5 and Figure 6 As shown in FIG. 1 , the wall portion 41W of the first conductive member 41 is plastically deformed toward the reduced diameter portion 42n of the second conductive member 42. As a result, a portion of the first conductive member 41 flows relative to the reduced diameter portion 42n of the second conductive member 42. As a result, as shown in FIG. Figure 6As shown, the edge of the recessed portion 41r of the first conductive member 41 is pressed into the reduced diameter portion 42n of the second conductive member 42, thereby fastening the first conductive member 41 and the second conductive member 42. In the fastening step, various fastening methods for mechanically fastening the first conductive member 41 and the second conductive member 42 can be adopted as described above.

[0069] After the first conductive member 41 and the second conductive member 42 are fastened to form the fastening portion 43 , the first conductive member 41 and the second conductive member 42 are then metal-bonded to each other.

[0070] In the metal joining process, a metal joining portion 45 is formed at the interface between the first conductive component 41 and the second conductive component 42 at a position closer to the inner circumference than the fastening portion 43. In this embodiment, the first conductive component 41 and the second conductive component 42 are metal-joined by an ultrasonic joining portion. Although detailed illustrations are omitted, in the metal joining process, the fastened first conductive component 41 and the second conductive component 42 are clamped by a horn and an anvil, and ultrasonic vibrations are imparted to the joining interface via the horn. For example, it may be configured such that: the anvil is inserted into the cylindrical portion 42c2 of the second conductive component 42, the horn is pressed against the approximate center of the second surface 41b of the first conductive component 41, and ultrasonic vibrations are imparted to the first conductive component 41. As a result, a metal joining portion 45 is formed at the approximate center of the interface between the recessed portion 41r of the first conductive component 41 and the protruding portion 42p of the second conductive component 42 (see Figure 3 ) In addition, in the metal bonding step, as described above, various bonding methods for bonding the first conductive member 41 and the second conductive member 42 by metallurgical bonding can be adopted.

[0071] <Method of Manufacturing Power Storage Device 100>

[0072] The power storage device 100 can be manufactured using a terminal (in this embodiment, the negative terminal 40) manufactured by the above-mentioned method for manufacturing a terminal for a power storage device. The method for manufacturing the power storage device 100 includes an insertion step and a caulking step. The method for manufacturing the power storage device 100 may also include a preparation step for preparing a battery terminal.

[0073] First, the negative terminal 40 can be prepared by the above-mentioned method for manufacturing a terminal for a storage device. In addition, the electrode body 10, the outer body 22 of the case 20, and the sealing plate 24 can be prepared. The electrode body 10 can be attached to the sealing plate 24 via the negative electrode current collecting member 14 and the positive electrode current collecting member 13 by a known method.

[0074] like Figure 3As shown, in the insertion step, the connection portion 42c of the second conductive member 42 is inserted into the opening 14h of the negative electrode current collecting member 14. In addition, in the insertion step, the negative terminal 40 is inserted into the terminal mounting hole 24h of the housing 20 (in this embodiment, the sealing plate 24). At this time, the gasket 50 and the insulator 60 are arranged on the sealing plate 24.

[0075] In the insertion process, the connection portion 42c of the second conductive member 42 is inserted into the opening 14h and the terminal mounting hole 24h while the positions of the cylindrical portion 51 of the gasket 50, the opening 14h of the negative electrode current collecting member 14, the terminal mounting hole 24h of the sealing plate 24, and the hole portion 60h of the insulator 60 are aligned. As a result, the connection portion 42c of the negative electrode terminal 40 protrudes from the sealing plate 24 on the surface opposite to the surface on which the flange portion 42f is arranged. In this embodiment, the solid portion 42c1 in the connection portion 42c is inserted into the terminal mounting hole 24h of the sealing plate 24. At least a portion of the cylindrical portion 42c2 in the connection portion 42c protrudes from the opening 14h of the negative electrode current collecting member 14. The positive terminal 30 is also inserted into the opening of the sealing plate 24 in the same manner.

[0076] After the insertion process, the riveting process is performed. Figure 7 is a schematic diagram showing the riveting process. Figure 7 , a cross section of the negative electrode terminal 40 is schematically shown. Figure 7 In FIG. 4 , the connection portion 42 c before being deformed by the punch 91 is shown by a dotted line, and the connection portion 42 c after being deformed by the punch 91 is shown by a solid line. Figure 7 In the figure, the sealing plate 24, the gasket 50, the insulator 60, and the negative electrode current collecting member 14 are omitted. In the caulking step, the connecting portion 42c of the second conductive member 42 is caulked to the negative electrode current collecting member 14.

[0077] Here, the second conductive member 42 of the negative electrode terminal 40 is caulked to the negative electrode current collecting member 14. The cylindrical portion 42c2 protruding from the opening 14h of the negative electrode current collecting member 14 is caulked to the negative electrode current collecting member 14 in such a manner that a compressive force is applied in the up-down direction Z. Here, the caulking is performed in a state where the gasket 50 is sandwiched between the negative electrode terminal 40 and the sealing plate 24, and the insulator 60 is sandwiched between the sealing plate 24 and the negative electrode current collecting member 14.

[0078] like Figure 7As shown, in the riveting process, a riveting device including a punch (punching tool) 91 and a die (supporting tool) 92 can be used. The punch 91 can be any shape that can deform the connecting portion 42c of the second conductive component 42. The shapes of the punch 91 and the die 92 are appropriately set according to the shapes of the first conductive component 41 and the second conductive component 42. In this embodiment, the punch 91 is a roughly truncated cone shape whose front end is narrower than the inner circumferential surface of the cylindrical portion 42c2. The die 92 has a configuration surface along the shape of the negative terminal 40. The negative terminal 40 is configured in the die 92. Here, in the first conductive component 41, the second surface 41b on the side opposite to the side on which the second conductive component 42 is configured is configured in the die 92.

[0079] Next, the front end of the punch 91 is inserted into the connecting portion 42c (preferably the cylindrical portion 42c2) of the second conductive component 42. The side circumferential surface of the punch 91 hits the cylindrical portion 42c2, causing the cylindrical portion 42c2 to expand outward. The front end of the connecting portion 42c is plastically deformed and expanded. Thus, a rivet portion 40c is formed on the negative terminal 40, and each component is riveted and fixed. The positive terminal 30 is also riveted and fixed to the opening of the sealing plate 24 in the same manner.

[0080] As described above, through the insertion process and the riveting process, Figure 3 As shown, the positive terminal 30 and the negative terminal 40 are fixed to the sealing plate 24. Next, the electrode body 10 integrated with the sealing plate 24 by a known method is accommodated in the outer body 22. The sealing plate 24 is joined to the periphery of the opening 22h of the outer body 22. The joining is implemented by a conventionally known method (for example, laser welding). The storage device 100 is sealed by injecting electrolyte from the injection hole and plugging the injection port. As described above, the storage device 100 can be manufactured.

[0081] In addition, when the terminal for the storage device is installed on the storage device, the terminal for the storage device is inserted into the terminal mounting hole of the sealing plate and fixed by rivet. At this time, a conductive component, an electrode body, etc. are installed on the sealing plate. When an electrode body, etc. are installed on the sealing plate, from the perspective of operability, it is difficult to post-process the terminal for the storage device after the terminal for the storage device is fixed by rivet relative to the sealing plate. For example, in the case of using a terminal in which a plurality of conductive components are mechanically fastened and metal-joined as a terminal for the storage device, the terminal for the storage device needs to be prepared in advance. However, according to the experiment of the inventor, when a terminal for the storage device composed of a plurality of conductive components is prepared in advance and fixed by rivet to the sealing plate, it is sometimes impossible to maintain the joint between the components constituting the terminal for the storage device well. It was confirmed that when the terminal for the storage device is riveted and fixed to the sealing plate, the portion other than the connection portion of the terminal for the storage device is also plastically deformed.

[0082] In the negative terminal 40 described above, in the first conductive member 41, the fastening portion 43 is located at a position on the outer peripheral side than the metal joint portion 45. In the negative terminal 40, the outer peripheral edge 41o of the first conductive member 41 and the outer peripheral edge 42fo of the flange portion 42f of the second conductive member 42 are set at substantially the same position in the radial direction of the flange portion 42f. In this case, for example, compared with the form in which the first conductive member covers the periphery of the flange portion of the second conductive member, the amount of the first conductive member 41 relative to the second conductive member 42 can be smaller. Thus, the deformation amount of the entire first conductive member 41 that is deformed along with the deformation of the connecting portion 42c of the second conductive member 42 is suppressed. As a result, the deformation amount at the position closer to the radial inside than the fastening portion 43 can also be suppressed to be low. As a result, it is easy to maintain the metal joint portion 45 closer to the radial inside than the fastening portion 43. In addition, when the first conductive member 41 is deformed, the first conductive member 41 is also easily deformed toward the radial outside along the flange portion 42f. This can reduce the amount of deformation at the radially inner side of the fastening portion 43. As a result, the metal joint 45 can be easily maintained, and the conduction reliability of the negative electrode terminal 40 can be improved.

[0083] like Figure 3 As shown, it is preferred that an insulating member (resin member) such as a gasket 50 is disposed in a manner opposed to the boundary portion between the outer peripheral edge 41o of the first conductive member 41 and the outer peripheral edge 42fo of the flange portion 42f of the second conductive member 42. It is preferred that the insulating member such as the gasket 50 extends from the area in contact with the sealing plate 24 to a position opposed to the outer peripheral edge 41o of the first conductive member 41. Thus, it is possible to suppress the adhesion of water and the like to the first conductive member 41 and the second conductive member 42. Therefore, it is possible to more effectively suppress terminal corrosion.

[0084] It is preferable that the shape of the first conductive member 41 in a plan view is a substantially circular shape, and the shape of the flange portion 42 f of the second conductive member 42 in a plan view is a substantially circular shape.

[0085] In addition, a load is easily applied to the region (first region A1) of the first conductive component 41 corresponding to the connection portion 42c deformed in the second conductive component 42. In this case, the portion outside the first region A1 is easily deformed. As a result, the first conductive component 41 is not easily deformed in the second region A2 inside the first region A1. As a result, the metal joint 45 is easily maintained, and the conduction reliability of the negative terminal 40 can be improved.

[0086] In this embodiment, an annular rib 41ri is formed between the first area A1 and the second area A2 on the second surface 41b of the first conductive component 41. The rib 41ri is formed outside the second area A2. The rib 41ri is formed by partially overlapping the inner area of ​​the first area A1. By providing the rib 41ri, it is easy to suppress the deformation of the second area A2. As a result, it is easier to reduce the load applied to the metal joint 45. In addition, the rib 41ri may not be provided.

[0087] The thinner the thickness of the first region A1 is, the greater the effect can be. For example, the thinner the thickness of the first region A1 is, the more the deformation of the second region A2 is suppressed. In addition, when the external conductive member 48 and the bus bar 90 (see FIG. 1 ) are welded to the rib 41ri, Figure 4 ) etc., it is possible to reduce the load applied to the metal joint 45. From this viewpoint, the thickness of the first region A1 is preferably 1.5 mm or less, and more preferably 0.8 mm or less.

[0088] In addition, the use form of the rib 41ri is not particularly limited. The bus bar 90 may be welded to the rib 41ri, or the bus bar 90 may be welded at a position outside the rib 41ri. In addition, the external conductive component 48 may be welded to the rib 41ri. Thus, it is possible to prevent the welded portion between the external conductive component 48 and the first conductive component 41 from reaching the second conductive component 42. As a result, the reliability of the welded portion can be improved.

[0089] In addition, from the viewpoint of suppressing the deformation of the second region A2, in the first conductive component 41, it is preferred that the first region A1 and the second region A2 have approximately the same thickness. When the thickness of the first region A1 is set to T1 and the thickness of the second region A2 is set to T2, it is preferred to satisfy 0.8<T1 / T2<1.2, and more preferably to satisfy 0.9<T1 / T2<1.1. In addition, it is particularly preferred that the thickness of the first region A1 is thinner, for example, preferably less than 1.5 mm, and more preferably less than 0.8 mm. In addition, when the thickness of the flange portion 42f of the second conductive component 42 is set to T3, it is preferred that T1 / T3 is less than 1 / 3. By setting it to this size, the first conductive component 41 easily extends outward along the flange portion 42f of the second conductive component 42, and the deformation of the second region A2 can be suppressed. The thickness of the first area A1 and the thickness of the second area A2 described above are thicknesses of portions excluding the rib 41 ri, and are thicknesses from the upper surface 42 u to the bottom 41 r 2 of the recess 41 r .

[0090] In the above-described embodiment, the first region A1 and the second region A2 are included in the region where the recess 41r is formed in a plan view. However, the positional relationship among the first region A1, the second region A2, and the recess 41r is not limited to this form. Figure 8FIG. 1 is a cross-sectional view of a negative electrode terminal 140 according to another embodiment. Figure 8 In the embodiment, the same reference numerals are used for the structures common to the negative electrode terminal 40 described above, and detailed description thereof will be omitted. Figure 8 As shown, the recess 141r of the first conductive component 141 is formed at a position overlapping with the first area A1 in a top view. The opening 141r1 of the recess 141r is provided at a position overlapping with the first area A1. In the first area A1, the thickness of the first surface 141a of the first conductive component 141 is thicker than the bottom 141r2 of the recess 141r. In this case, it is preferred that the height difference between the upper surface of the first area A1 and the upper surface of the second area A2 is 2 mm or less.

[0091] The relationship between the thickness T1 of the first region A1 and the thickness T2 of the second region A2 can be determined according to the structure of the first conductive member 41 and the second conductive member 42 (see Figure 7 ) is different. Figure 8 In the illustrated embodiment, when the thickness of the first region A1 in the first conductive component 141 (the thickness between the first surface 141a and the second surface 141b of the first conductive component 141) is set to T11 and the thickness of the second region A2 (the thickness between the bottom 141r2 of the recess 141r and the second surface 141b) is set to T12, preferably T11>T12 is satisfied, more preferably T11 / T12>1.1, and further preferably T11 / T12>1.2 is satisfied. Since the thickness T11 of the first region A1 and the thickness T12 of the second region A2 are in such a relationship, it is easy to suppress the deformation of the second region A2 and to maintain the bonding of the metal bonding portion 45.

[0092] Above, various descriptions have been given to the technology disclosed herein. Unless otherwise specifically mentioned, the embodiments cited herein do not limit the present invention. In addition, the technology disclosed herein can be subjected to various changes, and each component and each process mentioned herein can be appropriately omitted or appropriately combined as long as no special problems are caused.

Claims

1. A power storage device comprising: An electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; A housing for accommodating the electrode body; a terminal electrically connected to the first electrode and mounted on the housing; as well as a current collecting member disposed in the housing and electrically connecting the first electrode to the terminal; The terminal includes a first conductive member formed of a first metal and a second conductive member formed of a second metal different from the first metal. The first conductive component has a recessed portion on the first surface. A portion of the second conductive member is disposed in the recessed portion, The first conductive member includes a fastening portion mechanically fastened to the second conductive member and a metal bonding portion metal-bonded to the second conductive member. In the first conductive member, the fastening portion is located on the outer peripheral side of the metal joint portion. in, The second conductive member includes a flange portion and a connecting portion formed on one surface of the flange portion. The front end of the connecting portion has an expanded diameter portion, and the expanded diameter portion is connected to the current collecting component. A portion of the flange portion is disposed in the recessed portion, The outer peripheral edge of the first conductive member and the outer peripheral edge of the flange portion are located at substantially the same position in the radial direction of the flange portion.

2. The power storage device according to claim 1, wherein When viewed along the direction in which the connecting portion extends, the first conductive member includes a first region that overlaps with the enlarged diameter portion, and a second region that is located on the inner side of the first region. The metal joint is formed in the second region.

3. The power storage device according to claim 2, wherein: An annular rib is formed between the first region and the second region.

4. The power storage device according to claim 3, wherein: Having external conductive parts, The external conductive member is welded to the annular rib.

5. The power storage device according to any one of claims 2 to 4, wherein When the thickness of the first region is T1 and the thickness of the second region is T2, 0.8<T1 / T2<1.2 is satisfied.

6. A terminal for an electric storage device, comprising a first conductive member composed of a first metal, and a second conductive member composed of a second metal different from the first metal, The first conductive component has a recessed portion on the first surface. A portion of the second conductive member is disposed in the recessed portion, The first conductive member includes a fastening portion mechanically fastened to the second conductive member and a metal bonding portion metal-bonded to the second conductive member. In the first conductive member, the fastening portion is located on the outer peripheral side of the metal joint portion. in, The second conductive member includes a flange portion and a connecting portion formed on one surface of the flange portion. The front end of the connecting portion has an expanded diameter portion, A portion of the flange portion is disposed in the recessed portion, The outer peripheral edge of the first conductive member and the outer peripheral edge of the flange portion are located at substantially the same position in the radial direction of the flange portion.

7. A method for manufacturing an electric storage device, the electric storage device comprising: An electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; A housing for accommodating the electrode body; a terminal electrically connected to the first electrode and mounted on the housing; as well as a current collecting member disposed in the housing and electrically connecting the first electrode to the terminal; The terminal includes a first conductive member formed of a first metal and a second conductive member formed of a second metal different from the first metal. The first conductive component has a recessed portion on the first surface. A portion of the second conductive member is disposed in the recessed portion, The first conductive member includes a fastening portion mechanically fastened to the second conductive member and a metal bonding portion metal-bonded to the second conductive member. In the first conductive member, the fastening portion is located on the outer peripheral side of the metal joint portion. in, The second conductive member includes a flange portion and a connecting portion formed on one surface of the flange portion. The front end of the connecting portion has an expanded diameter portion, and the expanded diameter portion is connected to the current collecting component. A portion of the flange portion is disposed in the recessed portion, The outer peripheral edge of the first conductive member and the outer peripheral edge of the flange portion are located at substantially the same position in the radial direction of the flange portion. The method for manufacturing the power storage device comprises: an inserting step of inserting the connecting portion of the second conductive member into the opening of the current collecting member; and A riveting step of riveting the connection portion to the current collecting member after the inserting step.

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