Terminal for power storage device, and power storage device

Abstract

The invention relates to a terminal for a power storage device and a power storage device. A negative electrode terminal of the present invention includes a first conductive member and a second conductive member. The first conductive member has a first recess in the first surface. The second conductive member has a flange portion and a shaft portion. At least a portion of the flange portion is disposed in the first recess portion. The first conductive member has a metal bonding portion that is metal-bonded to the flange portion. The flange portion has a large-diameter portion and a small-diameter portion. The outer diameter of the small-diameter portion is 9 / 10 or less of the outer diameter of the large-diameter portion. The outer peripheral side surface of the small-diameter section has a fastening section that is mechanically fastened to the inner surface of the first recess.

Description

Technical Field

[0001] The present invention relates to a terminal for an electricity storage device and an 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 of each component in a terminal for a power storage device to which a plurality of components are connected.

[0005] The terminal for a storage device disclosed herein includes a first conductive component made of a first metal, and a second conductive component made of a second metal different from the first metal. The first conductive component has a first recess on the first surface. The second conductive component has a flange portion and a shaft portion provided on one surface of the flange portion. At least a portion of the flange portion is disposed in the first recess. The first conductive component has a metal joint portion that is metal-joined with the flange portion. The flange portion has a large diameter portion and a small diameter portion. The outer diameter of the small diameter portion is less than 9 / 10 of the outer diameter of the large diameter portion. The small diameter portion is located on a side away from the shaft portion compared to the large diameter portion. The outer peripheral side surface of the small diameter portion has a fastening portion that is mechanically fastened to the inner surface of the first recess. The upper surface of the large diameter portion is in contact with the first conductive component.

[0006] In this power storage device terminal, 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 3 It 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 is a schematic diagram of the external conductive component 48.

[0012] Figure 6 It is a cross-sectional view of the negative electrode terminal 40 .

[0013] Figure 7 It is a perspective view of the second conductive member 42 .

[0014] Figure 8 is a schematic diagram of the protrusion 42p.

[0015] Fig. 9 It is a schematic diagram of a protrusion 42p involved in another embodiment.

[0016] Fig.10 It is a cross-sectional view of a negative electrode terminal 40A according to another embodiment.

[0017] Fig.11 It is a cross-sectional view of a negative electrode terminal 40B according to another embodiment.

[0018] Fig.12 It is a cross-sectional view of a negative electrode terminal 40C according to another embodiment.

[0019] Fig.13 It is a cross-sectional view of a negative electrode terminal 40D according to another embodiment.

[0020] Fig.14 It is a cross-sectional view of a negative electrode terminal 40E according to another embodiment. DETAILED DESCRIPTION

[0021] 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.

[0022] 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.

[0023] <Electricity Storage Device 100>

[0024] 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 4 2 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.

[0025] like Figure 2 As shown, the power storage device 100 includes an electrode body 10, a housing 20, a positive terminal 30, and a negative terminal 40. 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 other structures 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. Preferably, the power storage device 100 is a square 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 composed of the electrode body 10 and the electrolyte not shown in the figure housed in the housing 20.

[0026] 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.

[0027] 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).

[0028] 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.

[0029] 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 may also be different from that of the positive electrode collector component 13. The negative electrode collector component 14 may 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.

[0030] The electrolyte can be the same as before and there is no particular limitation. 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, a fluorine-containing lithium salt such as LiPF6. However, the electrolyte can also be integrated with the electrode body 10 in a solid state (solid electrolyte).

[0031] 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).

[0032] The outer casing 22 has a bottom surface 22d. The sealing plate 24 is opposite to the bottom surface 22d of the outer casing 22. The sealing plate 24 is mounted on the outer casing 22 in such a manner as to block the opening 22h of the outer casing 22. Here, the sealing plate 24 is substantially rectangular. In addition, in this specification, "substantially rectangular" is a term that includes, in addition to a complete rectangular shape (rectangle), a shape in which the corners connecting the long sides and the short sides of the rectangle are arc-shaped, a shape having a cutout at the corner, and the like.

[0033] 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".

[0034] 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.

[0035] 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 negative terminal 40 side 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".

[0036] 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 rivet portion 40c of the negative terminal 40 described later before riveting processing. The terminal mounting hole 24h is formed to be smaller than the flange portion 42f of the negative terminal 40 described later.

[0037] The negative electrode current collector 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 collector 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 rivet portion 40c of the negative terminal 40 described later before the rivet processing. The negative electrode current collector component 14 is fixed to the sealing plate 24 together with the negative terminal 40 by rivet processing. It is preferred that a resin insulating component is arranged between the housing 20 (in this embodiment, the sealing plate 24) and the negative electrode current collector component 14. In this embodiment, the negative electrode current collector component 14 is fixed to the sealing plate 24 together with the negative terminal 40 in an insulated state separated by the insulator 60.

[0038] 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.

[0039] 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 rivet portion 40c 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 as to be able to insert the rivet portion 40c of the negative terminal 40 before the rivet processing. 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.

[0040] 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.

[0041] <Negative terminal 40>

[0042] 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.

[0043] In the negative electrode terminal 40 , two types of conductive members, ie, a first conductive member 41 and a second conductive member 42 are electrically connected to each other via a metal joint 45 .

[0044] 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 is riveted to the negative current collecting component 14. In detail, it is riveted to the peripheral portion surrounding the opening 14h of the negative current collecting component 14. A rivet 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 rivet portion 40c is cylindrical. However, the shape of the rivet portion 40c is not limited to a cylindrical shape, and may be any shape such as a columnar shape. In addition, it is preferred that the rivet 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.

[0045] <First Conductive Member 41 >

[0046] 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).

[0047] The diameter of the first conductive component 41 is preferably greater than the thickness. In this embodiment, the first conductive component 41 is plate-shaped (specifically, a flat plate). The first conductive component 41 is preferably roughly disk-shaped 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 bonded to the second conductive component 42.

[0048] The first conductive component 41 has a first recess 41R on the first surface 41a. The first recess 41R is formed in the approximate center of the first surface 41a of the first conductive component 41. The first recess 41R is a portion where at least a portion of the flange portion 42f is configured. Preferably, the first recess 41R has a portion in which a small diameter portion 42fb of the flange portion 42f described later is configured, and a portion in which a large diameter portion 42fa is configured. Preferably, the first recess 41R includes a portion in which at least the small diameter portion 42fb is configured. In this embodiment, the first recess 41R is configured with a portion of the large diameter portion 42fa and the small diameter portion 42fb. The first recess 41R has a shape corresponding to the small diameter portion 42fb and the large diameter portion 42fa. Therefore, a portion of the outer peripheral side surface of the large diameter portion 42fa contacts the inner peripheral side surface of the first recess 41R of the first conductive component 41. In this way, it is preferable that the inner peripheral side surface of the first recessed portion 41R of the first conductive member 41 is arranged radially outside the outer peripheral side surface of the large-diameter portion 42 fa of the second conductive member 42 .

[0049] The shape of the first recess 41R is not particularly limited, but in this embodiment, the first recess 41R has a first bottom surface 41R1 and a second bottom surface 41R2 of different depths. The first bottom surface 41R1 is arranged at a position deeper than the second bottom surface 41R2. Here, the first bottom surface 41R1 is arranged at the deepest position in the first recess 41R. In other words, the first bottom surface 41R1 is arranged at a position farthest from the opening 41R3 in the first recess 41R. The first bottom surface 41R1 is a substantially circular surface having a shape corresponding to the upper surface 42u1 of the small diameter portion 42fb in the flange portion 42f of the second conductive component 42. The second bottom surface 41R2 is arranged between the first bottom surface 41R1 and the opening 41R3. The second bottom surface 41R2 is a substantially annular surface having a shape corresponding to the upper surface 42u of the large diameter portion 42fa in the flange portion 42f.

[0050] The first recess 41R is recessed into a roughly circular shape with a roughly constant diameter from the opening 41R3 toward the second bottom surface 41R2. The large diameter portion 42fa has an outer diameter corresponding to the inner diameter of the side closer to the opening 41R3 than the second bottom surface 41R2 in the first recess 41R. In other words, the large diameter portion 42fa is a roughly disc-shaped portion having a diameter roughly the same as the inner diameter of the first recess 41R from the opening 41R3 to the first bottom surface 41R1. In this embodiment, the thickness of the large diameter portion 42fa is set to be slightly larger than the length from the second bottom surface 41R2 to the opening 41R3. Therefore, the large diameter portion 42fa protrudes slightly downward from the first surface 41a of the first conductive component 41. The dimensional relationship between the large diameter portion 42fa and the first recess 41R in the height direction is not limited to this dimensional relationship.

[0051] The first recess 41R is recessed into a substantially truncated cone shape from the second bottom surface 41R2 to the first bottom surface 41R1. The second bottom surface 41R2 is convex inward relative to the first bottom surface 41R1. Therefore, the side surface of the first recess 41R is tapered in a manner that the diameter gradually decreases from the first bottom surface 41R1 toward the second bottom surface 41R2. In other words, the side surface of the first recess 41R is tapered in a manner that the diameter gradually increases from the second bottom surface 41R2 toward the first bottom surface 41R1.

[0052] The second surface 41b is a surface on the opposite side to the first surface 41a. In this embodiment, an annular rib 41ri is formed on the second surface 41b of the first conductive component 41. The rib 41ri can be continuously formed into a circular ring shape. On the second surface 41b, an external conductive component 48 is welded and joined via the rib 41ri. 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).

[0053] like Figure 4 As shown, when manufacturing the battery pack 200 , the bus bar 90 is connected to the external conductive member 48 connected to the first conductive member 41 . Figure 5 is a schematic diagram of the external conductive component 48. Figure 5 , the external conductive member 48 and the bus bar 90 are schematically shown as viewed from the upper surface. Figure 5 In FIG. 4 , the second conductive component 42 hidden in the external conductive component 48 is indicated by a dotted line. Figure 5 As shown, the bus bar 90 is connected to the external conductive member 48 at the bus bar welding portion 48a. The bus bar 90 and the external conductive member 48 can be welded by laser welding or the like. In addition, it is also possible to configure such that the external conductive member 48 is not necessarily mounted on the second surface 41b of the first conductive member 41. Figure 4 ), the bus bar 90 may be directly connected to the first conductive member 41 without passing through the external conductive member 48 .

[0054] <Second Conductive Member 42 >

[0055] like Figure 3As shown, the second conductive component 42 is a component that is inserted through the terminal mounting hole 24h and extends from the inside to the outside of the housing 20. 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, stainless steel, iron, and an iron alloy. 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, etc.

[0056] The second conductive component 42 has a flange portion 42f and a shaft portion 42s (connecting portion). The shaft portion 42s is a portion connected to the negative electrode current collector component 14 and becomes a rivet portion 40c. The shaft portion 42s is provided on one surface of the flange portion 42f (in this embodiment, the lower surface 42d). The shaft portion 42s is a portion 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 collector component 14. A base 52 of a gasket 50 is arranged between the flange portion 42f and the sealing plate 24. A barrel portion 51 of a gasket 50 is arranged between the shaft portion 42s and the sealing plate 24. The shaft portion 42s is enlarged toward the front end. The enlarged portion is connected to the negative electrode current collector component 14. The enlarged diameter portion is also called a caulking portion 40c, and is preferably connected to the negative current collecting member 14 by caulking while being inserted into the opening 14h of the negative current collecting member 14. From the viewpoint of improving conductivity, the caulking portion 40c is preferably joined to a portion of the negative current collecting member 14 by laser welding or the like.

[0057] The flange portion 42f is a portion having a larger diameter than the shaft portion 42s in the plane direction (X direction and Y direction). In other words, the flange portion 42f is a portion having a larger diameter at one end of the shaft portion 42s than the shaft portion 42s. The flange portion 42f is a portion disposed outside the housing 20. The flange portion 42f is connected to the first conductive member 41.

[0058] The shape of the flange portion 42f is not particularly limited. In a top view along the direction (height direction) in which the shaft portion 42s extends, the flange portion 42f may be, for example, roughly circular or roughly polygonal. Preferably, the flange portion 42f is roughly circular in a top view. The roughly circular shape is not limited to a completely circular shape, and includes a shape in which a cutout is formed in a portion of the outer peripheral surface. Preferably, at least a portion of the outer periphery of the flange portion 42f is circular. For example, preferably, in the thickness direction of the flange portion 42f, the shape of the outer periphery that surrounds the same height is circular.

[0059] Figure 6is a cross-sectional view of the negative electrode terminal 40. Figure 6 , a cross section near the interface between the first conductive component 41 and the second conductive component 42 is shown. Figure 6 In the figure, the sealing plate 24, the gasket 50, the insulator 60, the negative electrode current collecting member 14 and the like are omitted.

[0060] like Figure 6 As shown, the flange portion 42f has a large diameter portion 42fa and a small diameter portion 42fb. The large diameter portion 42fa is a portion having a larger diameter than the small diameter portion 42fb. The large diameter portion 42fa is a substantially disc-shaped portion having substantially the same diameter in the thickness direction (height direction). In other words, the outer peripheral edge of the upper surface 42u of the large diameter portion 42fa is circular. A small diameter portion 42fb protruding upward is formed in the substantially central portion of the upper surface 42u of the large diameter portion 42fa. The small diameter portion 42fb is located on a side farther from the shaft portion 42s than the large diameter portion 42fa. The large diameter portion 42fa and the small diameter portion 42fb are shaped along the first recess 41R. The diameter of the small diameter portion 42fb increases as it moves toward the front end side (the side away from the flange portion 42f). The diameter of the small diameter portion 42fb decreases as it moves from the front end toward the base end. In addition, the diameter of the small diameter portion 42fb may also be smaller than the diameter of the shaft portion 42s.

[0061] The negative terminal 40 has a contact portion C where the first conductive member 41 contacts the second conductive member 42. At least a portion of the flange portion 42f is disposed in the first recess 41R. A portion of the flange portion 42f of the second conductive member 42 contacts the first conductive member 41 in the first recess 41R. The first conductive member 41 has a metal joint portion 45 at the contact portion C. The metal joint portion 45 is a joint portion where the first conductive member 41 and the flange portion 42f of the second conductive member 42 are joined by metal joining. The metal joint portion 45 is formed at the center of the upper surface of the flange portion 42f.

[0062] Here, metal bonding refers to bonding a plurality of metal parts to each other by metallurgical bonding, excluding bonding based on mechanical fastening. Preferably, the metal bonding portion 45 is formed by ultrasonic bonding, diffusion bonding, laser welding, etc. From the viewpoint of suppressing the formation of fragile intermetallic compounds at the bonding interface, the metal bonding portion 45 is preferably an ultrasonic bonding portion formed by ultrasonic bonding. In this embodiment, the metal bonding portion 45 is an ultrasonic bonding portion that bonds the first conductive component 41 to the second conductive component 42 by ultrasonic bonding.

[0063] In this embodiment, the metal joint 45 is formed on the upper surface 42u1 of the small diameter portion 42fb. From the viewpoint of suppressing corrosion caused by an electrolyte or water, the metal joint 45 is preferably formed by metal bonding the upper surface of the flange portion 42f to the bottom surface of the recessed portion of the first conductive member 41 (in this embodiment, the first bottom surface 41R1 of the first recessed portion 41R). More preferably, the metal joint 45 is formed in the central portion of the upper surface of the flange portion 42f.

[0064] The negative terminal 40 has a fastening portion 43. The fastening portion 43 is a portion that mechanically fastens the first conductive member 41 and the second conductive member 42. The fastening portion 43 is formed by mechanically fastening the outer peripheral side surface of the small diameter portion 42fb and the inner surface of the first recess 41R. The fastening portion 43 is formed along the outer peripheral side surface of the small diameter portion 42fb.

[0065] The fastening portion 43 is realized between the small diameter portion 42fb of the flange portion 42f and the first bottom surface 41R1 and the second bottom surface 41R2 of the first recess 41R. Here, the small diameter portion 42fb of the flange portion 42f is fitted with the side circumference between the first bottom surface 41R1 and the second bottom surface 41R2 protruding toward the inside in the first recess 41R of the first conductive component 41. In other words, the small diameter portion 42fb of the flange portion 42f is pressed into the first recess 41R of the first conductive component 41 and is riveted with the side circumference between the second bottom surface 41R2 and the first bottom surface 41R1.

[0066] The form of the fastening portion 43 is not particularly limited as long as it is a mechanical fastening based on dynamic energy. The fastening portion 43 may be a portion fastened by, for example, press fitting, shrink fitting, caulking, riveting, folding, bolting, or the like.

[0067] The upper surface 42u of the large diameter portion 42fa is in contact with the first conductive component 41. Here, the upper surface 42u refers to the surface in contact with the first conductive component 41, and is the surface on the side opposite to the lower surface 42d from which the shaft portion 42s extends. In this embodiment, the upper surface 42u of the large diameter portion 42fa is in contact with the second bottom surface 41R2 of the first recess 41R of the first conductive component 41. And limited to this form, the upper surface 42u of the large diameter portion 42fa can also be in contact with the first surface 41a of the first conductive component 41. The surface of the upper surface 42u of the large diameter portion 42fa in contact with the first conductive component 41 can be changed according to the shapes of the first conductive component 41 and the second conductive component 42, etc.

[0068] According to the inventors' understanding, in a terminal for a power storage device having a fastening portion for mechanically fastening a plurality of conductive members, there is a possibility that the fastening portion may be damaged as the power storage device is used. For example, when the electrolyte contacts the exposed portion of the boundary between the conductive members due to vibration during use of the power storage device, there is a concern that the fastening portion may be damaged.

[0069] In the negative terminal 40, the outer diameter of the small diameter portion 42fb is set smaller than the outer diameter of the large diameter portion 42fa. Since the outer diameter of the small diameter portion 42fb is smaller than the outer diameter of the large diameter portion 42fa, the distance between the fastening portion 43 formed on the outer peripheral side of the small diameter portion 42fb and the boundary portion of the first conductive member 41 and the second conductive member 42 is ensured. Along the radial direction of the flange portion 42f, the length of the upper surface 42u of the large diameter portion 42fa in contact with the first conductive member 41 becomes longer. According to this structure, for example, even if the electrolyte contacts the exposed portion of the boundary between the first conductive member 41 and the second conductive member 42 due to vibration during use of the power storage device 100, the electrolyte or water is difficult to reach the small diameter portion 42fb. As a result, the reduction in the reliability of the fastening portion 43 caused by corrosion of the interface between the first conductive member 41 and the second conductive member 42 in the fastening portion 43 is suppressed. According to the findings of the present inventors, when the outer diameter of the small diameter portion 42fb is 9 / 10 or less of the outer diameter of the large diameter portion 42fa, a decrease in the reliability of the fastening portion 43 is effectively suppressed.

[0070] In addition, the outer diameters of the large diameter portion 42fa and the small diameter portion 42fb refer to the outer diameters of the portions of the respective portions with the largest diameter from the central axis CL. In this embodiment, the outer diameter of the small diameter portion 42fb refers to the outer diameter of the upper surface 42u1 on the front end side of the small diameter portion 42fb. In this embodiment, the outer diameter of the large diameter portion 42fa is substantially constant in the axial direction, and therefore refers to the outer diameter at any position in the axial direction.

[0071] For example, it is more preferred that the outer diameter of the small diameter portion 42fb is less than 4 / 5 of the outer diameter of the large diameter portion 42fa, and more preferably less than 2 / 3. Thus, the reliability of the fastening portion 43 is further improved. In addition, for example, it is preferred that the difference between the outer diameter of the large diameter portion 42fa and the outer diameter of the small diameter portion 42fb is set to be greater than 1 mm, more preferably greater than 2 mm, and more preferably greater than 3 mm. In addition, it is preferred that the outer diameter of the small diameter portion 42fb is, for example, greater than 1 / 5 of the outer diameter of the large diameter portion 42fa. Thus, the reliability of the fastening portion 43 is further improved.

[0072] The fastening portion 43 is arranged at a position away from the end C1 of the contact portion C. In this embodiment, the end C1 of the contact portion C is the position of the opening 41R3 of the first conductive member 41 where the second recess 41r is formed. The end C1 is a portion exposed from the contact surface between the first conductive member 41 and the second conductive member 42. From the viewpoint of suppressing corrosion caused by an electrolyte or water, the fastening portion 43 is preferably arranged at a position away from the end C1 of the contact portion C. The shortest creepage distance between the fastening portion 43 and the end C1 of the contact portion C is, for example, preferably 1 mm or more, more preferably 2 mm or more, and further preferably 3 mm or more. Here, the creepage distance is the distance along the contact portion C. In this embodiment, it is the distance from the opening 41R3 of the second recess 41r of the first conductive member 41 to the base end of the small diameter portion 42fb of the second conductive member 42, and is the distance along the inner peripheral side surface of the first conductive member 41 or the outer peripheral side surface of the second conductive member 42.

[0073] In the above-mentioned embodiment, the contact portion C is also formed on the outer peripheral side surface of the large diameter portion 42fa of the flange portion 42f. As a result, the shortest creepage distance between the fastening portion 43 and the end C1 of the contact portion C becomes larger than the length of the contact portion C on the outer peripheral side surface of the large diameter portion 42fa. As a result, the fastening portion 43 is less likely to be corroded by electrolyte or water.

[0074] In addition, in the form where the inner peripheral side of the first recess 41R is arranged radially outside the outer peripheral side of the large diameter portion 42fa, a gap may be provided between the outer peripheral side of the large diameter portion 42fa and the inner peripheral side of the first recess 41R. According to this structure, a more stable fastening portion 43 can be formed. Although not particularly limited, the gap between the outer peripheral side of the large diameter portion 42fa and the inner peripheral side of the first recess 41R may be, for example, 1 mm or less, or 0.5 mm or less.

[0075] In addition, various connection structures other than the above-mentioned fastening portion 43 and the metal joint portion 45 may be provided in the first conductive member 41 and the second conductive member 42 .

[0076] In this embodiment, a groove 42fc is provided on the outer peripheral side of the flange portion 42f. The groove 42fc is a portion where a portion of the flange portion 42f is reduced in diameter, and is also referred to as a reduced diameter portion. A portion of the first conductive component 41 is disposed in the groove 42fc. According to this structure, the first conductive component 41 and the second conductive component 42 are more firmly fastened, and the reliability of the negative terminal 40 can be improved. The groove 42fc is formed at the boundary portion between the large diameter portion 42fa and the small diameter portion 42fb. The groove 42fc can be formed continuously along the circumference of the flange portion 42f, can be formed intermittently, or can be formed locally. Preferably, the groove 42fc is continuously formed in an annular shape along the circumference of the flange portion 42f. In this embodiment, the groove 42fc is continuous in the circumferential direction, and the outer peripheral edge of the thinnest portion (reduced diameter portion) of the groove 42fc is circular. The length of the groove 42fc relative to the circumference is preferably 0.5 or more, more preferably 0.7 or more, and further preferably 0.9 or more. Here, the above-mentioned circumference refers to the circumference of the side circumferential surface of the flange portion 42f at a location where the groove 42fc is formed.

[0077] In this embodiment, a protrusion 42p is provided on the second conductive component 42. The protrusion 42p is provided at a position closer to the outer peripheral side than the metal joint 45. The protrusion 42p is provided at the contact portion C between the first conductive component 41 and the second conductive component 42. The protrusion 42p is formed on the upper surface 42u of the large diameter portion 42fa in the upper surface of the flange portion 42f. The protrusion 42p is provided at a position away from the end C1 of the contact portion C on the second conductive component 42. The shortest creepage distance between the protrusion 42p and the end C1 of the contact portion C is preferably 1 mm or more, more preferably 2 mm or more, and further preferably 3 mm or more. The protrusion 42p is preferably provided at a position closer to the inner diameter side than a position 0.9 times the diameter from the center axis CL to the flange portion 42f, more preferably provided at a position closer to the inner diameter side than a position 0.8 times, and further preferably provided at a position closer to the inner diameter side than a position 0.6 times.

[0078] Figure 7 It is a perspective view of the second conductive member 42 . Figure 8 is a schematic diagram of the protrusion 42p. Fig. 9 FIG. 4 is a schematic diagram of a protrusion 42p according to another embodiment. Figure 7 As shown, the protrusion 42p is arranged near the small diameter portion 42fb in the upper surface 42u of the large diameter portion 42fa. The protrusion 42p can be connected to the small diameter portion 42fb or can be away from the small diameter portion 42fb. In this embodiment, the protrusion 42p is connected to the small diameter portion 42fb and is arranged radially from the base end of the small diameter portion 42fb.

[0079] The protrusion 42p is preferably provided on the upper surface 42u of the large diameter portion 42fa near the root (base end) of the small diameter portion 42fb. Thus, the risk of corrosion at the interface between the protrusion 42p and the second recess 41r caused by electrolyte or water can be reduced. For example, the protrusion 42p is preferably provided on the upper surface 42u of the large diameter portion 42fa at a position within 5 mm from the root of the small diameter portion 42fb, more preferably at a position within 3 mm, and further preferably at a position within 1 mm.

[0080] like Figure 8 As shown in FIG. 1 , the front end of the protrusion 42p is flat. The cross section of the protrusion 42p along the length direction (radial direction of the flange portion 42f) is substantially trapezoidal. The shape of the protrusion 42p is not limited to this form. Fig. 9 As shown, the shape of the front end may be pointed. The cross section of the protrusion 42p along the length direction may also be roughly triangular. The size and shape of the protrusion 42p are not particularly limited. From the perspective of the durability of the protrusion 42p, the aspect ratio A / B represented by the height B of the protrusion 42p relative to the width A of the base end of the protrusion 42p is preferably 1 or more.

[0081] like Figure 7 and Figure 8 As shown, the protrusion 42p is formed along the radial direction. The length of the protrusion 42p in the radial direction is not particularly limited. For example, the length of the protrusion 42p in the radial direction is preferably 0.25 mm or more, and more preferably 0.5 mm or more. In addition, the length of the protrusion 42p in the radial direction is preferably 5 mm or less, and more preferably 3 mm or less.

[0082] like Figure 5 As shown, six protrusions 42p are provided on the upper surface 42u of the large diameter portion 42fa of the flange portion 42f. The six protrusions 42p are provided at substantially the same distance from the central portion in the radial direction. As for the spacing of the protrusions 42p, for example, they can be provided at substantially equal intervals in the circumferential direction. In addition, the number, configuration, spacing, etc. of the protrusions 42p are not particularly limited. The number of protrusions 42p may also be one. From the viewpoint of improving the conductivity between the first conductive component 41 and the second conductive component 42, the number of protrusions 42p is preferably multiple, and more preferably 4 or more. From the viewpoint of productivity, the number of protrusions 42p may be, for example, less than 20, less than 12, or less than 8.

[0083] like Figure 6As shown, the protrusion 42p of the second conductive component 42 is embedded in the first conductive component 41. In other words, the first conductive component 41 has a second recess 41r that is embedded with the protrusion 42p of the second conductive component 42. The first conductive component 41 has the same number of second recesses 41r as the protrusion 42p of the second conductive component 42. The second recesses 41r are formed in the same position as the protrusion 42p and in a shape corresponding to the protrusion 42p. In this way, the protrusion 42p of the second conductive component 42 and the second recess 41r of the first conductive component 41 are embedded at the interface between the first conductive component 41 and the second conductive component 42. According to this structure, the first conductive component 41 and the second conductive component 42 can be tightened more strongly. In addition, even in the case where an external connecting component such as the bus bar 90 acts a force in the circumferential direction with the central axis CL of the negative terminal 40 as the axis (refer to Figure 4 ), and it is not easy to apply a load in a direction that causes the first conductive component 41 to rotate relative to the second conductive component 42. As a result, it is easy to maintain the metal joint 45 in the negative terminal 40, and the conduction reliability between the first conductive component 41 and the second conductive component 42 can be good. From this point of view, it is preferred that a plurality of second recesses 41r and protrusions 42p are provided.

[0084] Furthermore, metal bonding may be formed at the interface between the second recess 41r of the first conductive member 41 and the protrusion 42p of the second conductive member 42. Thus, the conductivity between the first conductive member 41 and the second conductive member 42 can be improved.

[0085] In the above-mentioned embodiment, the second conductive component 42 has a protrusion 42p. The first conductive component 41 has a second recess 41r for the protrusion 42p to fit in. However, it is not limited to this form. It is sufficient that at least one of the first conductive component and the second conductive component is provided with a protrusion, and the other is provided with a second recess. For example, it is also possible to configure such that the first conductive component has a protrusion, and the second conductive component has a second recess that fits in with the protrusion. In addition, it is also possible that both the first conductive component and the second conductive component have a protrusion. In this case, the first conductive component and the second conductive component each have a second recess that fits in with the protrusion of the other.

[0086] However, from the viewpoint of fitting the protrusion provided on one conductive component with the other conductive component, it is preferable that the conductive component made of a metal with a larger Vickers hardness be provided in the first conductive component 41 and the second conductive component 42. From this viewpoint, it is preferable that the second conductive component 42 has at least the protrusion 42p.

[0087] For example, the form of the fastening portion 43 is not particularly limited as long as it is a mechanical fastening based on dynamic energy. The fastening portion 43 can be a portion fastened by, for example, press fitting, shrink fitting, caulking, riveting, folding, bolting, or the like.

[0088] <Method for Manufacturing Negative Electrode Terminal 40>

[0089] 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.

[0090] In the preparation step, the first conductive member 41 and the second conductive member 42 are prepared. As the second conductive member 42, the second metal of the above-mentioned shape is prepared. In this embodiment, as the first conductive member 41, a metal having lower rigidity than the second conductive member 42 is used. As the first conductive member 41, a conductive member set in a shape that is deformed along the large diameter portion 42fa, the small diameter portion 42fb, and the groove 42fc of the second conductive member 42 when riveted in the fastening step is prepared.

[0091] 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 caulking the first conductive member 41 with respect to the second conductive member 42.

[0092] In the fastening process, first, the first conductive component 41 is arranged in a mold (not shown). In this embodiment, the second conductive component 42 is punched relative to the first conductive component 41 in such a manner that the flange portion 42f of the second conductive component 42 is inserted into the first recess 41R of the first conductive component 41. At this time, a known pushing device (not shown) or the like can be used. The first conductive component 41 is flattened because its rigidity is lower than that of the second conductive component 42, and is plastically deformed along the second conductive component 42. The edge of the first recess 41R of the first conductive component 41 is pressed into the groove 42fc of the second conductive component 42, thereby fastening the first conductive component 41 and the second conductive component 42. In the fastening process, as described above, various fastening methods for mechanically fastening the first conductive component 41 and the second conductive component 42 can be adopted.

[0093] A gap may be provided between the outer peripheral side surface of the large diameter portion 42fa and the inner peripheral side surface of the first recess 41R. According to this structure, the large diameter portion 42fa can be easily inserted into the first recess 41R, and a stable fastening portion 43 can be easily formed.

[0094] The second conductive member 42 is provided with a protrusion 42p. In the fastening step, when the second conductive member 42 is pressed against the first conductive member 41, the protrusion 42p may be fitted into the first conductive member 41 to form the second recess 41r in the first conductive member 41.

[0095] 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.

[0096] In the metal bonding process, a metal bonding portion 45 is formed at the interface between the first conductive component 41 and the second conductive component 42. In this embodiment, the first conductive component 41 and the second conductive component 42 are metal-bonded by an ultrasonic bonding portion. Although detailed illustrations are omitted, in the metal bonding process, the first conductive component 41 and the second conductive component 42 that are fastened are clamped by a horn and an anvil, and ultrasonic vibrations are imparted to the bonding interface via the horn. For example, the anvil may be inserted into the cylindrical portion of the shaft portion 42s of the second conductive component 42, the horn may be pressed against the approximate center portion of the second surface 41b of the first conductive component 41, and ultrasonic vibrations may be imparted to the first conductive component 41. As a result, a metal bonding portion 45 is formed at the approximate center portion of the interface between the first bottom surface 41R1 of the first recess 41R of the first conductive component 41 and the upper surface 42u1 of the small diameter portion 42fb of the second conductive component 42. When the bonding head is pressed against the first conductive member 41, the first conductive member 41 is pressed against the second conductive member 42. Thus, the protrusion 42p may be fitted into the first conductive member 41 to form the second recess 41r in the first conductive member 41.

[0097] In the metal bonding process, ultrasonic vibration is applied to the first conductive member 41, so that the first conductive member 41 can also vibrate at the contact interface between the second recess 41r of the first conductive member 41 and the protrusion 42p of the second conductive member 42. Thus, a metal bonding portion can also be formed at the contact interface between the second recess 41r and the protrusion 42p. From the viewpoint of facilitating metal bonding, a shape that tapers toward the front end of the protrusion (a shape with a small area at the front end) is preferred.

[0098] The closer to the position where the welding head contacts, the easier it is to conduct the ultrasonic vibration imparted by the welding head. Therefore, the closer the position of the protrusion 42p and the second recess 41r is to the position where the welding head contacts (in this embodiment, the approximate center of the second surface 41b of the first conductive member 41) it is to form a good metal joint at the interface between the protrusion 42p and the second recess 41r.

[0099] In the above-mentioned embodiment, the second conductive component 42 prepared in the preparation process is pre-set with a protrusion 42p. However, it is not limited to this form, and the first conductive component prepared in the preparation process may be pre-set with a protrusion. In addition, in the preparation process, the first recess may be pre-set in at least one of the first conductive component and the second conductive component. In the fastening process, a protrusion along the first recess of one component may be formed in the other of the first conductive component and the second conductive component. However, from the viewpoint of firmly fastening the protrusion 42p and the second recess 41r, it is preferred that a protrusion is pre-set at the position where the second metal joint is formed.

[0100] The structure of the negative electrode terminal 40 is not limited to the above-mentioned embodiment. Fig.10 It is a cross-sectional view of a negative electrode terminal 40A according to another embodiment. Fig.11 It is a cross-sectional view of a negative electrode terminal 40B according to another embodiment. Fig.12 It is a cross-sectional view of a negative electrode terminal 40C according to another embodiment. Fig.13 It is a cross-sectional view of a negative electrode terminal 40D according to another embodiment. Fig.14 FIG. 4 is a cross-sectional view of a negative electrode terminal 40E according to another embodiment. Figures 10 to 14 In the figure, 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.

[0101] exist Fig.10 In the negative terminal 40A shown in the figure, the first recess 41R of the first conductive member 41 is set to a shape and size such that only the small diameter portion 42fb of the flange portion 42f of the second conductive member 42 is arranged. In the first recess 41R, the second bottom surface 41R2 is not formed (see Figure 6 ). The shape of the first recess 41R follows the shape of the small diameter portion 42fb. In this embodiment, the upper surface of the large diameter portion 42fa of the flange portion 42f contacts the first surface 41a of the first conductive component 41. The dimensional relationship between the large diameter portion 42fa of the second conductive component 42 and the first conductive component 41 in the radial direction of the flange portion 42f is not particularly limited. In this embodiment, the size of the large diameter portion 42fa of the second conductive component 42 and the first conductive component 41 is set to be substantially the same. Thus, the outer diameter of the negative terminal 40A can be maintained, the size of the small diameter portion 42fb can be increased, and the depth of the first recess 41R can be deepened. Thus, the bonding strength at the fastening portion 43 can be increased. In addition, by increasing the ratio of the second conductive component 42 to the negative terminal 40A, the conductivity of the first conductive component 41 and the second conductive component 42 can be improved. As a result, the heat generation during power-on is suppressed, and the durability of the power storage device 100 can be improved.

[0102] exist Fig.11In the negative terminal 40B shown, the protrusion 42p is provided on the upper surface 42u of the large diameter portion 42fa of the flange portion 42f. The protrusion 42p is provided at the peripheral portion of the large diameter portion 42fa and the substantially central portion of the base end of the small diameter portion 42fb. In this way, the protrusion 42p does not necessarily need to be provided near the root of the small diameter portion 42fb. By providing the protrusion 42p at a position away from the root of the small diameter portion 42fb, the durability can be improved with respect to the load acting in the direction of rotating the first conductive member 41 relative to the second conductive member 42.

[0103] exist Fig.12 In the negative terminal 40C shown, the protrusion 42p is provided on the upper surface 42u1 of the small diameter portion 42fb of the flange portion 42f. According to this structure, the interface between the protrusion 42p and the second recess 41r is away from the end C1 of the contact portion C. As a result, it is possible to reduce corrosion of the interface between the protrusion 42p and the second recess 41r caused by electrolyte or water.

[0104] exist Fig.13 The negative terminal 40D and Fig.14 In the negative terminal 40E shown, the cross section of the protrusion 42p is substantially triangular in the circumferential direction of the flange 42f. In the cross section along the circumferential direction of the flange 42f, the tip of the protrusion 42p is pointed, thereby making it easy to impart ultrasonic vibration to the interface between the first conductive member 41 and the second conductive member 42 in a state of mutual contact. As a result, metal bonding is easily generated at the interface between the protrusion 42p and the second recess 41r.

[0105] Above, various descriptions have been made 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 as long as no special problems are caused, each component and each process mentioned herein can be appropriately omitted or appropriately combined. In addition, this specification includes the disclosures recorded in the following items.

[0106] Item 1:

[0107] A terminal for an electrical storage device, comprising: a first conductive component, formed of a first metal; and a second conductive component, formed of a second metal different from the first metal, wherein the first conductive component has a first recess on a first surface, the second conductive component has a flange portion, and a shaft portion provided on one surface of the flange portion, at least a portion of the flange portion is disposed in the first recess, the first conductive component has a metal joint portion metal-joined with the flange portion, the flange portion has a large diameter portion and a small diameter portion, the outer diameter of the small diameter portion is less than 9 / 10 of the outer diameter of the large diameter portion, the small diameter portion is located on a side away from the shaft portion compared to the large diameter portion, the outer peripheral side surface of the small diameter portion has a fastening portion mechanically fastened to the inner surface of the first recess, and the upper surface of the large diameter portion is in contact with the first conductive component.

[0108] Item 2:

[0109] The terminal for an electric storage device according to Item 1, wherein a groove is provided on an outer peripheral side surface of the small-diameter portion, and a part of the first conductive member is arranged in the groove.

[0110] Item 3:

[0111] The terminal for a power storage device according to item 1 or 2, wherein the terminal has a contact portion where the first conductive member contacts the second conductive member, and the fastening portion is arranged at a position away from an end portion of the contact portion.

[0112] Item 4:

[0113] According to the terminal for a storage device as described in Item 3, one side of the protrusion and the second recess is provided at a position of the end of the second conductive component away from the contact portion, and the first conductive component has the other side of the protrusion and the second recess which are engaged with one side of the protrusion and the second recess.

[0114] Item 5:

[0115] The terminal for a power storage device according to Item 4, wherein the second conductive member has one of the protrusion and the second recess on the upper surface of the large diameter portion and near the base of the small diameter portion.

[0116] Item 6:

[0117] The terminal for an electric storage device according to any one of Items 3 to 5, wherein the contact portion is also formed on an outer peripheral side surface of the large diameter portion of the flange portion.

[0118] Item 7:

[0119] A power storage device, comprising: an electrode body including a positive electrode and a negative electrode; a housing accommodating the electrode body; and a terminal electrically connected to the positive electrode or the negative electrode and mounted on the housing, the terminal 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, wherein the first conductive member has a first recessed portion on a first surface, the second conductive member has a flange portion and a shaft portion provided on one surface of the flange portion, at least a portion of the flange portion is arranged in the first recessed portion, the first conductive member has a metal joint portion metal-joined with the flange portion, the flange portion has a large diameter portion and a small diameter portion, the outer diameter of the small diameter portion is less than 9 / 10 of the outer diameter of the large diameter portion, the small diameter portion is located on a side away from the shaft portion compared to the large diameter portion, the outer peripheral side surface of the small diameter portion has a fastening portion mechanically fastened to the inner surface of the first recessed portion, and the upper surface of the large diameter portion is in contact with the first conductive member.

Claims

1. A terminal for an electric storage device, comprising: a first conductive member made of a first metal; and a second conductive member made of a second metal different from the first metal, in, The first conductive component has a first recessed portion on the first surface. The second conductive member includes a flange portion and a shaft portion provided on one surface of the flange portion. At least a portion of the flange portion is disposed in the first recessed portion, The first conductive member has a metal joint portion metal-joined to the flange portion, The flange portion has a large diameter portion and a small diameter portion, The outer diameter of the small diameter portion is less than 9 / 10 of the outer diameter of the large diameter portion, The small diameter portion is located at a side farther from the shaft portion than the large diameter portion. The outer peripheral side surface of the small diameter portion has a fastening portion that is mechanically fastened to the inner surface of the first recessed portion. An upper surface of the large diameter portion is in contact with the first conductive member.

2. The terminal for a power storage device according to claim 1, wherein A groove is provided on an outer peripheral side surface of the small diameter portion, and a part of the first conductive member is arranged in the groove.

3. The terminal for an electric storage device according to claim 1 or 2, wherein: having a contact portion where the first conductive member contacts the second conductive member, The fastening portion is arranged at a position away from an end portion of the contact portion.

4. The terminal for a power storage device according to claim 3, wherein: A projection and a second recess are provided at a position of an end of the second conductive member away from the contact portion, The first conductive member includes the protrusion and the second recess that fit into the other of the protrusion and the second recess.

5. The terminal for an electric storage device according to claim 4, wherein: The second conductive member has one of the protrusion and the second recess on the upper surface of the large diameter portion and near the base of the small diameter portion.

6. The terminal for a power storage device according to claim 3, wherein: The contact portion is also formed on the outer peripheral side surface of the large diameter portion of the flange portion.

7. An electric storage device comprising: An electrode body, including a positive electrode and a negative electrode; a housing accommodating the electrode body; and A terminal, electrically connected to the positive electrode or the negative electrode and mounted on the housing, The terminal comprises: a first conductive member made of a first metal; and a second conductive member made of a second metal different from the first metal; in, The first conductive component has a first recessed portion on the first surface. The second conductive member includes a flange portion and a shaft portion provided on one surface of the flange portion. At least a portion of the flange portion is disposed in the first recessed portion, The first conductive member has a metal joint portion metal-joined to the flange portion, The flange portion has a large diameter portion and a small diameter portion, The outer diameter of the small diameter portion is less than 9 / 10 of the outer diameter of the large diameter portion, The small diameter portion is located at a side farther from the shaft portion than the large diameter portion. The outer peripheral side surface of the small diameter portion has a fastening portion that is mechanically fastened to the inner surface of the first recessed portion. An upper surface of the large diameter portion is in contact with the first conductive member.

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