Power storage device, terminal for power storage device, and method for manufacturing power storage device

Abstract

To provide a terminal in which a first conductive member and a second conductive member are connected to each other in a reliable connection part, and a power storage device having the terminal.SOLUTION: A power storage device 100 includes an electrode 10, a case 20, a negative electrode 40, and a negative electrode collector member 14. The negative terminal 40 includes a first conductive member 41 and a second conductive member 42. The first conductive member 41 has a recessed part 41r in a first surface 41a. The first conductive member 41 has a fastening part 43 and a metal joint part 45. The second conductive member 42 has a flange part 42f and a connection part 42c. The connection part 42c has a diameter increasing part 42e in the top end. The diameter increasing part 42e is connected to the negative electrode collector member 14. A part of the flange part 42f is arranged in the recessed part 41r of the first conductive member 41. The outer periphery 41o of the first conductive member 41 and the outer periphery 42fo of the flange part 42f are located in practically the same position in the radial direction of the flange part 42f.SELECTED DRAWING: Figure 3

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 an electricity storage device. [Background technology]

[0002] JP 2022-049726 A discloses a terminal including a plate-shaped metal first member and a metal second member ultrasonically welded to one surface of the first member. A recess is formed in the surface of the first member opposite to the surface to which the second member is welded. The first member and the second member are ultrasonically welded to each other in the recess. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-049726 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors wish to further improve the reliability of connections between a plurality of members in a terminal for an electricity storage device in which the members are connected. [Means for solving the problem]

[0005] The electricity storage device disclosed herein includes an electrode body, a case that houses the electrode body, a terminal, and a current collecting member. The electrode body includes a first electrode and a second electrode having a polarity different from that of the first electrode. The case houses the electrode body. The terminal is electrically connected to the first electrode and attached to the case. The current collecting member is disposed in the case and electrically connects the first electrode and the terminal. The terminal includes a first conductive member made of a first metal and a second conductive member made of a second metal different from the first metal. The first conductive member has a recess on a first surface. A part of the second conductive member is disposed in the recess. The first conductive member has a fastening portion mechanically fastened to the second conductive member and a metal joint portion that is metal-joined to the second conductive member. In the first conductive member, the fastening portion is located on the outer periphery side of the metal joint portion. The second conductive member has a flange portion and a connection portion formed on one surface of the flange portion. A tip of the connection portion has an enlarged diameter portion. The enlarged diameter portion is connected to the current collecting member. A portion of the flange is disposed within the recess. An outer circumferential edge of the first conductive member and an outer circumferential edge of the flange are located at substantially the same position in a radial direction of the flange.

[0006] Such an electricity storage device has a highly reliable connection between the first conductive member and the second conductive member. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of the electricity storage device 100. As shown in FIG. [Diagram 2] FIG. 2 is a schematic vertical cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 3 is a cross-sectional view showing the negative electrode terminal 40 attached to the sealing plate 24. As shown in FIG. [Figure 4] FIG. 4 is a perspective view showing the battery pack 200. As shown in FIG. [Diagram 5] FIG. 5 is a cross-sectional view showing first conductive member 41 and second conductive member 42 before they are fastened in the fastening step. [Figure 6] FIG. 6 is a cross-sectional view showing first conductive member 41 and second conductive member 42 after they have been fastened in the fastening step. [Figure 7] FIG. 7 is a schematic diagram showing the crimping process. [Figure 8] FIG. 8 is a cross-sectional view of a negative electrode terminal 140 according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the technology disclosed herein will be described with reference to the drawings. The embodiment described herein is, of course, not intended to limit the present invention in particular. Each drawing is drawn diagrammatically and does not necessarily reflect the actual product. In addition, the same reference numerals are appropriately used for members and parts that perform the same function, and duplicated descriptions are appropriately omitted. In the following description, the reference numerals L, R, F, Rr, U, and D in the drawings represent left, right, front, rear, top, and bottom, and the reference numerals X, Y, and Z in the drawings represent the long side direction, short side direction, and height direction of the storage device, respectively. However, these are merely directions for convenience of description, and do not limit the installation form of the storage device in any way.

[0009] In this specification, the term "electricity storage device" refers to all electricity storage devices capable of extracting electric energy. Electricity storage devices include secondary batteries that can be repeatedly charged and discharged by the movement of charge carriers between a pair of electrodes (positive and negative electrodes) via an electrolyte, as well as capacitors such as electric double layer capacitors. Hereinafter, an embodiment of a method for manufacturing an electricity storage device will be described for a lithium ion secondary battery.

[0010] <Electricity storage device 100> FIG. 1 is a perspective view of an electricity storage device 100. FIG. 2 is a schematic longitudinal sectional view taken along line II-II in FIG. 1. In FIG. 2, the gasket 50 and the insulator 60 are omitted. FIG. 3 is a sectional view showing a negative electrode terminal 40 attached to a sealing plate 24. FIG. 4 is a perspective view showing a battery pack 200. FIG. 4 illustrates a configuration in which a plurality of electricity storage devices 100 disclosed herein are connected in series via bus bars 90, with the electricity storage device 100 serving as a single cell.

[0011] As shown in FIG. 2, the electricity storage device 100 includes an electrode assembly 10, a case 20, a positive electrode terminal 30, a negative electrode terminal 40, a positive electrode current collector 13, and a negative electrode current collector 14. The electricity storage device 100 may include an external conductive member 48. The electricity storage device 100 is characterized by including the positive electrode terminal 30 and / or the negative electrode terminal 40 disclosed herein, and other configurations may be similar to those of the conventional device. The electricity storage device 100 is preferably a secondary battery, and more preferably a non-aqueous electrolyte secondary battery. Here, the electricity storage device 100 is a lithium ion secondary battery. Although not shown, the electricity storage device 100 further includes an electrolyte. The electricity storage device 100 is configured by housing the electrode assembly 10 and an electrolyte (not shown) in a case 20.

[0012] The electrode body 10 may be the same as a conventional one, 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 via a strip-shaped separator, and wound around a winding axis. However, in other embodiments, the electrode body 10 may be a laminated electrode body in which a square-shaped (typically rectangular) positive electrode and a square-shaped (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".

[0013] The positive electrode has a positive electrode current collector 11 and a positive electrode mixture layer (not shown) fixed on the positive electrode current collector 11. The positive electrode current collector 11 is made of a conductive metal such as aluminum, an aluminum alloy, nickel, or stainless steel. The positive electrode mixture layer contains a positive electrode active material (for example, a lithium transition metal complex oxide). The negative electrode has a negative electrode current collector 12 and a negative electrode mixture layer (not shown) fixed on the negative electrode current collector 12. The negative electrode current collector is made of a conductive metal such as copper, a copper alloy, nickel, or stainless steel. The negative electrode mixture layer contains a negative electrode active material (for example, a carbon material such as graphite).

[0014] As shown by the diagonal lines in FIG. 2, a laminated portion is formed in the center of the long side direction X of the electrode body 10, in which the positive electrode mixture layer and the negative electrode mixture layer are laminated in an insulated state. Meanwhile, at the left end of the long side direction X of the electrode body 10, a part of the positive electrode current collector 11 where the positive electrode mixture layer is not formed (positive electrode current collector exposed portion) protrudes from the laminated portion. A positive electrode current collector member 13 is attached to the positive electrode current collector exposed portion. The positive electrode current collector member 13 may be made of the same metal material as the positive electrode current collector 11, for example, a conductive metal such as aluminum, an aluminum alloy, nickel, or stainless steel. The positive electrode current collector member 13 is disposed in the case 20. The positive electrode current collector member 13 electrically connects the positive electrode and the positive electrode terminal 30.

[0015] In addition, at the right end of the long side direction X of the electrode body 10, a part of the negative electrode current collector 12 on which the negative electrode mixture layer is not formed (negative electrode current collector exposed part) protrudes from the laminated part. A negative electrode current collector 14 is attached to the negative electrode current collector exposed part. The material (metal type) of the negative electrode current collector 14 may be different from that of the positive electrode current collector 13. The negative electrode current collector 14 may be made of the same metal type as that of the negative electrode current collector 12, for example, a conductive metal such as copper, a copper alloy, nickel, or stainless steel. The negative electrode current collector 14 is disposed in the case 20. The negative electrode current collector 14 electrically connects the negative electrode and the negative electrode terminal 40. The negative electrode current collector 14 electrically connects the negative electrode and the negative electrode terminal 40 inside the case 20.

[0016] The electrolyte may be the same as that used in the past 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 contains, 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 in a solid state (solid electrolyte) and may be integrated with the electrode body 10.

[0017] The case 20 is a housing that houses the electrode body 10. Here, the case 20 is formed in a flat, bottomed rectangular parallelepiped (rectangular). However, the shape of the case 20 is not limited to a rectangular shape, and may be any shape such as a cylinder. The material of the case 20 may be the same as that used conventionally, and is not particularly limited. The case 20 is made of a lightweight metal material with good thermal conductivity, such as aluminum, an aluminum alloy, or stainless steel. The case 20 includes an exterior body 22 having an opening 22h, and a sealing plate 24 that closes the opening 22h. The case 20 preferably includes the exterior body 22 and the sealing plate 24. The case 20 is integrated by joining (for example, welding) the sealing plate 24 to the periphery of the opening 22h of the exterior body 22. The case 20 is hermetically sealed (sealed).

[0018] The exterior body 22 has a bottom surface 22d. The sealing plate 24 faces the bottom surface 22d of the exterior body 22. The sealing plate 24 is attached to the exterior body 22 so as to close the opening 22h of the exterior body 22. The sealing plate 24 here has a substantially rectangular shape. Note that in this specification, the term "substantially rectangular shape" includes not only a perfect rectangular shape (rectangular shape) but also, for example, a shape in which the corners connecting the long and short sides of the rectangle are rounded, a shape in which the corners have notches, and the like.

[0019] The positive electrode terminal 30 and the negative electrode terminal 40 protrude to the outside of the case 20. Here, the positive electrode terminal 30 and the negative electrode terminal 40 each protrude from the same surface of the case 20 (specifically, the sealing plate 24). However, the positive electrode terminal 30 and the negative electrode terminal 40 may each protrude from different surfaces of the case 20. The positive electrode terminal 30 and the negative electrode terminal 40 are respectively disposed at both end portions of the sealing plate 24 in the long side direction X. The positive electrode terminal 30 and / or the negative electrode terminal 40 are an example of a "terminal for a power storage device."

[0020] As shown in FIG. 2, the positive electrode terminal 30 is electrically connected to the positive electrode of the electrode body 10 through the positive electrode current collector 13 inside the case 20. The negative electrode terminal 40 is electrically connected to the negative electrode of the electrode body 10 through the negative electrode current collector 14 inside the case 20. The positive electrode terminal 30 and the negative electrode terminal 40 are each attached to the case 20 (specifically, the sealing plate 24). It is preferable that the positive electrode terminal 30 and the negative electrode terminal 40 are fixed to the case 20 (specifically, the sealing plate 24). The positive electrode terminal 30 and the negative electrode terminal 40 are each insulated from the sealing plate 24 through a gasket 50 (see FIG. 3) and an insulator 60 (see FIG. 3).

[0021] The configurations of the positive electrode terminal 30 and the negative electrode terminal 40 of the electricity storage device 100 will be described in detail below, taking the terminal structure on the negative electrode terminal 40 side as an example. The terminal structure described below is preferably provided on the negative electrode terminal 40 side. The terminal structure described below may be provided on the positive electrode terminal 30 side, or may be provided on both the positive electrode terminal 30 side and the negative electrode terminal 40 side. In that case, in the following description, the word "negative electrode" can be appropriately read as "positive electrode".

[0022] As shown in FIG. 3, the sealing plate 24 is formed with a terminal mounting hole 24h penetrating in the up-down direction Z. The terminal mounting hole 24h is provided in the case 20 (the sealing plate 24 in this embodiment). It is preferable that the negative electrode terminal 40 is inserted into the terminal mounting hole 24h. Although not shown, the terminal mounting hole 24h is circular (for example, a perfect circle) in a plan view. The terminal mounting hole 24h has an inner diameter large enough to insert a connection portion 42c of the negative electrode terminal 40 before crimping, which will be described later. The terminal mounting hole 24h is formed smaller than a flange portion 42f of the negative electrode terminal 40, which will be described later.

[0023] The negative current collecting member 14 is attached to the negative current collecting exposed portion of the negative current collecting body 12, and constitutes a conductive path that electrically connects the negative electrode and the negative terminal 40. The negative current collecting member 14 has a flat portion 14f that spreads horizontally along the inner surface of the sealing plate 24. The flat portion 14f has an opening 14h at a position corresponding to the terminal mounting hole 24h. The opening 14h has an inner diameter large enough to insert a connecting portion 42c of the negative terminal 40 before crimping, which will be described later. The negative current collecting member 14 is fixed to the sealing plate 24 together with the negative terminal 40 by crimping. It is preferable that a resin insulating member is disposed between the case 20 (the sealing plate 24 in this embodiment) and the negative current collecting member 14. In this embodiment, the negative current collecting member 14 is fixed to the sealing plate 24 together with the negative terminal 40 in a state insulated via the insulator 60. The negative electrode current collecting member 14 is an example of a "current collecting member."

[0024] The gasket 50 is an insulating member disposed between the upper surface (outer surface) of the sealing plate 24 and the negative electrode terminal 40. An insulating member (e.g., gasket 50) is preferably disposed between the case 20 (e.g., sealing plate 24) and the negative electrode terminal 40. The gasket 50 here has a function of insulating the sealing plate 24 from the negative electrode terminal 40 and closing the terminal mounting hole 24h. The gasket 50 is made of an electrically insulating and elastically deformable resin material, for example, a fluorinated resin such as perfluoroalkoxy fluorine resin (PFA), polyphenylene sulfide resin (PPS), aliphatic polyamide, or the like.

[0025] The gasket 50 has a tubular portion 51 and a base portion 52. The tubular portion 51 is a portion that prevents direct contact between the sealing plate 24 and the connection portion 42c of the negative electrode terminal 40. The tubular portion 51 has a hollow cylindrical shape. The tubular portion 51 has a hole portion 51h that penetrates in the vertical direction Z. The hole portion 51h is formed so that the connection portion 42c of the negative electrode terminal 40 before crimping can be inserted therethrough. The tubular portion 51 is inserted into the terminal mounting hole 24h of the sealing plate 24. The base portion 52 is a portion that prevents direct contact between the sealing plate 24 and the flange portion 42f of the negative electrode terminal 40 described later. The base portion 52 is connected to the upper end of the tubular portion 51. The base portion 52 extends in the horizontal direction from the upper end of the tubular portion 51. The base portion 52 is formed, for example, in a circular ring shape so as to surround 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 52 is sandwiched between the lower surface 42d of the flange portion 42f of the negative electrode terminal 40 and the upper surface of the sealing plate 24, and is compressed in the vertical direction Z by crimping.

[0026] The insulator 60 is an insulating member disposed between the lower surface (inner surface) of the sealing plate 24 and the negative electrode current collecting member 14. An insulating member (e.g., the insulator 60) is preferably disposed between the case 20 (e.g., the sealing plate 24) and the negative electrode current collecting member 14. The insulator 60 has a flat plate-shaped portion that spreads horizontally along the inner surface of the sealing plate 24. A hole 60h is formed in this flat plate-shaped portion at a position corresponding to the terminal mounting hole 24h. The hole 60h has an inner diameter large enough to insert the connection portion 42c of the negative electrode terminal 40. The insulator 60 is made of a resin material that has resistance to the electrolyte used and electrical insulation properties, and is elastically deformable, for example, a fluorinated resin such as perfluoroalkoxy fluorine resin (PFA) or polyphenylene sulfide resin (PPS). The flat 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 member 14, and is compressed in the up-down direction Z by crimping.

[0027] <Negative terminal 40> The negative electrode terminal 40 includes a first conductive member 41 and a second conductive member 42. As shown in Fig. 3, the negative electrode terminal 40 extends from the inside to the outside of the case 20 through the terminal mounting hole 24h. The negative electrode terminal 40 may further include an external conductive member 48 connected to the first conductive member 41 on the outside of the case 20.

[0028] As described below, the negative electrode terminal 40 is configured by integrating two types of conductive members, namely, a first conductive member 41 and a second conductive member 42, with 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 via the fastening portion 43 and the metal joint portion 45.

[0029] 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 collector 14, and the tip end portion in the insertion direction (a cylindrical portion 42c2 described later) is crimped onto the negative current collector 14. More specifically, it is crimped to the peripheral portion surrounding the opening 14h of the negative current collector 14. A crimped portion 40c is formed at the lower end portion of the negative terminal 40. The negative terminal 40 is fixed to the sealing plate 24 by crimping and is electrically connected to the negative current collector 14. The crimped portion 40c is cylindrical here. However, the shape of the crimped portion 40c is not limited to a cylindrical shape and may be any shape such as a columnar shape. It is preferable that the crimped portion 40c is welded to the negative current collector 14. The first conductive member 41 and the second conductive member 42 constituting the negative terminal 40 will be described below.

[0030] <First conductive member 41> The first conductive member 41 is a member disposed outside the case 20. The first conductive member 41 is made of a first metal. The first metal is a conductive metal such as aluminum, an aluminum alloy, nickel, or stainless steel. The first metal side is preferably aluminum or an aluminum alloy. The first conductive member 41 is made of aluminum here. The first conductive member 41 is preferably made of a metal having a lower Vickers hardness (softer) than the second conductive member 42. The first conductive member 41 may be made of the same metal as the positive electrode current collecting member 13, or an alloy having the same metal element as the first component (the component having the highest mixing ratio by mass; the same applies below).

[0031] In this embodiment, the first conductive member 41 is plate-shaped (specifically, flat). The first conductive member 41 is substantially circular in plan view. The first conductive member 41 has a first surface 41a and a second surface 41b. The first surface 41a is a surface that is joined to the second conductive member 42. The second surface 41b is a surface opposite to the first surface 41a. In this embodiment, an external conductive member 48 is attached to the second surface 41b. The external conductive member 48 preferably extends along the longitudinal direction of the sealing plate 24. The external conductive member 48 is preferably made of the same type of metal as the first conductive member 41 (in this embodiment, aluminum or an aluminum alloy). The external conductive member 48 does not necessarily have to be attached to the second surface 41b. For example, an external conductive member such as a bus bar 90 (see FIG. 4) may be connected to the second surface 41b. When the battery pack 200 (see FIG. 4) is fabricated, the bus bar 90 may be directly connected to the first conductive member 41.

[0032] The first conductive member 41 has a recess 41r on the first surface 41a. The recess 41r is provided in approximately the center of the first conductive member 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 in the depth direction. A part of the second conductive member 42 is disposed in the recess 41r. The first conductive member 41 has a fastening portion 43 mechanically fastened to the second conductive member 42 and a metal joint portion 45 metal-jointed to the second conductive member 42.

[0033] <Second conductive member 42> The second conductive member 42 is a member that extends from the inside to the outside of the case 20 through the terminal mounting hole 24h. The second conductive member 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. The second metal is preferably made of copper or a copper alloy. Here, the second conductive member 42 is made of copper. The second conductive member 42 is preferably made of a metal that has a higher Vickers hardness (is harder) than the first conductive member 41. The second metal may be the same metal as the negative electrode current collecting member 14, or an alloy that has the same metal element as the first component. A part or all of the surface of the second conductive member 42 may be coated with another metal by Ni plating, tin plating, or the like.

[0034] The second conductive member 42 has a flange portion 42f and a connection portion 42c. The flange portion 42f is a portion of the second conductive member 42 that has a larger diameter in the surface direction (X direction and Y direction) compared to other portions. The flange portion 42f is a portion disposed outside the case 20. The flange portion 42f is connected to the first conductive member 41. The connection portion 42c is a portion that is inserted into the terminal mounting hole 24h of the case 20 (the sealing plate 24 in this embodiment) and the opening 14h of the negative electrode current collecting member 14. A base portion 52 of a gasket 50 is disposed between the flange portion 42f and the sealing plate 24. A tube portion 51 of the gasket 50 is disposed between the connection portion 42c and the sealing plate 24.

[0035] The flange portion 42f has an outer diameter shape corresponding to the planar shape of the first conductive member 41. The outer peripheral edge 41o of the first conductive member 41 and the outer peripheral edge 42fo of the flange portion 42f are located at substantially the same position in the radial direction of the flange portion 42f. For example, in the radial direction of the flange portion 42f, the dimension by which one of the outer peripheral edge 41o of the first conductive member 41 and the outer peripheral edge 42fo of the flange portion 42f protrudes from the other may be within 2 mm. The smaller the dimension by which one protrudes from the other, the more preferable, and it is more preferable that it is within 1 mm, and even more preferable that it is within 0.5 mm. In this embodiment, the flange portion 42f is substantially disc-shaped with substantially the same dimensions as the first surface 41a of the first conductive member 41. When the outer peripheral edge 41o of the first conductive member 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, when the negative terminal 40 is viewed from the radial direction of the flange portion 42f, the boundary between the outer peripheral edge 41o of the first conductive member 41 and the outer peripheral edge 42fo of the flange portion 42f can be confirmed along the circumferential direction.

[0036] The flange portion 42f has a protruding portion 42p and a constricted portion 42n. The protruding portion 42p is formed on an upper surface 42u of the flange portion 42f. The protruding portion 42p has a shape that conforms to the recessed portion 41r. The protruding portion 42p has a larger diameter toward the tip side (the side farther from the flange portion 42f). The protruding portion 42p has a smaller diameter toward the base end. The constricted portion 42n is a portion where a part of the side surface of the protruding portion 42p is constricted. The constricted portion 42n is a portion of the protruding portion 42p that is recessed and has a smaller diameter than other portions. In this embodiment, the constricted portion 42n is formed at the base end of the protruding portion 42p.

[0037] A part of the flange portion 42f (in this embodiment, the protruding portion 42p) is disposed in a 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. The form of the fastening portion 43 is not particularly limited as long as it is mechanically fastened by mechanical energy. The fastening portion 43 can be a portion fastened by, for example, press fitting, shrink fitting, caulking, riveting, folding, bolting, or the like.

[0038] The fastening portion 43 is preferably provided with a recess in the outer circumferential side wall of the flange portion 42f of the second conductive member 42, and a part of the first conductive member 41 is disposed in the recess. In this embodiment, a constricted portion 42n is provided as a recess in the outer circumferential side wall of the flange portion 42f of the second conductive member 42. The fastening portion 43 is realized by the recess 41r of the first conductive member 41 and the protruding portion 42p and the constricted portion 42n of the second conductive member 42. A part of the inner wall of the first recess 41r of the first conductive member 41 enters into the constricted portion 42n of the second conductive member 42. As a result, the inner wall of the first recess 41r of the first conductive member 41 is fixed (for example, pressed and fixed) by the constricted portion 42n of the second conductive member 42. In this way, the protruding portion 42p is fitted into the recess 41r. As a result, the first conductive member 41 and the second conductive member 42 are mechanically fastened. Moreover, the first conductive member 41 and the second conductive member 42 are joined by a metal joint 45. The metal joint 45 is located on the inner circumferential side of the fastening portion 43.

[0039] The metal joint 45 is a portion where the first conductive member 41 and the second conductive member 42 are metallically joined to each other. Here, the metal joint refers to a portion where a plurality of metal members are joined to each other by metallurgical joining, and does not include joining by mechanical fastening. The metal joint 45 can be formed by, for example, ultrasonic joining, diffusion joining, laser welding, or the like. From the viewpoint of suppressing the formation of a brittle intermetallic compound 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 member 41 and the second conductive member 42 are joined by ultrasonic joining.

[0040] The position of the metal joint 45 is not particularly limited as long as it is located on the inner circumferential side of the fastening portion 43. The first conductive member 41 has a first region A1 and a second region A2. The first region A1 is a region that overlaps with the expanded diameter portion 42e when viewed in the direction in which the connection portion 42c of the second conductive member 42 described later extends. The second region A2 is located inside the first region A1. Between the first region A1 and the second region A2, other regions may be provided, such as a region in which a rib 41ri described later is formed. In this embodiment, the direction in which the connection portion 42c extends corresponds to the thickness direction of a portion (sealing plate 24) in the case 20 where a terminal mounting hole 24h to which the negative electrode terminal 40 is attached is provided.

[0041] In this embodiment, the edge of the opening 41r1 of the recess 41r is formed outside the first region A1. Therefore, the first region A1 and the second region A2 are located inside the region in which the recess 41r is formed in a plan view along the direction in which the connecting portion 42c extends. The metal joint 45 is formed in the second region A2. It is preferable that the upper surface of the first region A1 and the upper surface of the second region A2 are substantially on the same plane. For example, the difference in height between the upper surface of the first region A1 and the upper surface of the second region A2 is preferably 2 mm or less, more preferably 1 mm or less, and even more preferably 0.5 mm or less.

[0042] In the first conductive member 41, the fastening portion 43 is located on the outer periphery side of the metal joint portion 45. In other words, the fastening portion 43 is located outside the metal joint portion 45 in the planar directions (X direction and Y direction) of the first conductive member 41. In this embodiment, the metal joint portion 45 is formed in the approximate center of the bottom 41r2 of the recess 41r of the first conductive member 41. Since the metal joint portion 45 is formed in the approximate center of the interface between the first conductive member 41 and the second conductive member 42, the metal joint portion 45 is less likely to be subjected to a load due to vibration of the power storage device 100, the bus bar 90 (see FIG. 4), etc.

[0043] The second conductive member 42 has a connection portion 42c connected to the negative current collecting member 14. The connection portion 42c is a portion formed on one surface (lower surface 42d in this embodiment) of the flange portion 42f. The connection portion 42c is provided on the surface opposite to the surface on which the protrusion 42p is formed. The tip of the connection portion 42c has an expanded diameter portion 42e. The expanded diameter portion 42e is a portion that expands in diameter toward the tip of the connection portion 42c. The expanded diameter portion 42e is connected to the negative current collecting member 14. The expanded diameter portion 42e is also referred to as a crimped portion 40c, and is crimped and connected to the negative current collecting member 14. From the viewpoint of improving electrical conductivity, it is preferable that the expanded diameter portion 42e and a part of the negative current collecting member 14 are joined by laser welding or the like.

[0044] 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 crimped portion 40c of the negative electrode terminal 40 described above. The solid portion 42c1 is a substantially cylindrical portion extending from the lower surface 42d of the flange portion 42f. The solid portion 42c1 extends from the substantially central portion of the lower surface 42d of the flange portion 42f. The solid portion 42c1 extends to the tip side of the connection portion 42c. The cylindrical portion 42c2 is a substantially cylindrical portion extending from the solid portion 42c1 toward the tip side before being connected to the negative electrode current collecting member 14. The cylindrical portion 42c2 is expanded in diameter when connected to the negative electrode current collecting member 14, and a part of the expanded diameter portion 42e is crimped onto the negative electrode current collecting member 14 and connected to the negative electrode current collecting member 14.

[0045] The configuration of the connection portion 42c is not particularly limited. From the viewpoint of facilitating the expansion of the diameter when connected to the negative electrode current collecting member 14, the connection portion 42c preferably has a cylindrical portion 42c2 on the tip side (the side farther from the flange portion 42f). The connection portion 42c may not be provided with a solid portion 42c1, and the cylindrical portion 42c2 may extend from the flange portion 42f. However, from the viewpoint of the strength of the connection portion 42c, it is preferable that the connection portion 42c is provided with a solid portion 42c1 extending from the flange portion 42f. The solid portion 42c1 can be set to a dimension corresponding to the thickness of the sealing plate 24, for example.

[0046] In the above-mentioned negative electrode terminal 40, a part of the interface between the first conductive member 41 and the second conductive member 42 is metal-jointed by the metal joint 45. This reduces the electrical resistance between the first conductive member 41 and the second conductive member 42. As a result, the electrical conductivity between the first conductive member 41 and the second conductive member 42 is good. The first conductive member 41 and the second conductive member 42 are mechanically fastened by the fastening portion 43 located on the outer periphery side of the metal joint 45. This allows the first conductive member 41 and the second conductive member 42 to be firmly connected. As a result, the metal joint 45 is easily maintained, and good electrical conductivity between the first conductive member 41 and the second conductive member 42 is easily maintained.

[0047] In the negative electrode terminal 40 described above, the outer peripheral edge 41o of the first conductive member 41 and the outer peripheral edge 42fo of the flange portion 42f are located at approximately the same position in the radial direction of the flange portion 42f. In the negative electrode terminal 40 having such a configuration, the dimension of the second conductive member 42 can be made approximately the same as the dimension of the first conductive member 41 in a plan view, and the diameter of the fastening portion 43 provided along the circumferential direction of the flange portion 42f can be increased. By increasing the diameter of the fastening portion 43, the joint strength of the fastening portion 43 is increased. As a result, the metal joint portion 45 is easily maintained, and good conductivity between the first conductive member 41 and the second conductive member 42 is more easily maintained. In addition, by increasing the ratio of the second conductive member 42 to the negative electrode terminal 40, the conductivity between the first conductive member 41 and the second conductive member 42 can be improved. As a result, heat generation due to current flow is suppressed, and the durability of the electricity storage device 100 can be improved.

[0048] <Method of Manufacturing Negative Electrode Terminal 40> The above-mentioned negative electrode terminal 40 can be manufactured, for example, by a manufacturing method for a terminal for an electricity storage device (in this embodiment, the negative electrode terminal 40) described below. The manufacturing method for a terminal for an electricity storage device includes a preparation step of preparing the first conductive member 41 and the second conductive member 42, a fastening step of fastening the first conductive member 41 and the second conductive member 42 together, and a metal joining step of metal-joining the first conductive member 41 and the second conductive member 42. The manufacturing method for a terminal for an electricity storage device may include other steps.

[0049] Fig. 5 is a cross-sectional view showing the first conductive member 41 and the second conductive member 42 before they are fastened in the fastening process. Fig. 6 is a cross-sectional view showing the first conductive member 41 and the second conductive member 42 after they are fastened in the fastening process. In Fig. 6, the shape of the first conductive member 41 before it is plastically deformed is shown by a dashed line. In Fig. 6, the direction in which the first conductive member 41 is plastically deformed is shown by an arrow.

[0050] In the preparation step, a first conductive member 41 and a second conductive member 42 are prepared. A second metal having the above-mentioned shape is prepared as the second conductive member 42. In this embodiment, a metal having a lower rigidity than the second conductive member 42 is used as the first conductive member 41. The first conductive member 41 is prepared in a shape that deforms along the protruding portion 42p and the narrowed portion 42n of the second conductive member 42 when it is crimped in the fastening step. In this embodiment, a first conductive member 41 having a recess 41R and a wall portion 41W is prepared (see FIG. 5). The recess 41R is a portion that becomes the recess 41r after the second conductive member 42 is accommodated.

[0051] Here, it is preferable that the outer peripheral edge 41o of the first conductive member 41 and the outer peripheral edge 42fo of the flange portion 42f have substantially the same shape. It is preferable that the outer peripheral edge 41o of the first conductive member 41 and the outer peripheral edge 42fo of the flange portion 42f have substantially the same dimensions. The dimensional difference between the outer peripheral edge 41o of the first conductive member 41 and the outer peripheral edge 42fo of the flange portion 42f may be, for example, within 2 mm, preferably within 1 mm, more preferably within 0.5 mm, and even more preferably 0 mm.

[0052] The inner diameter of the recess 41R is not particularly limited as long as the recess 41R has a dimension that allows the protrusion 42p of the second conductive member 42 to be inserted therein. In this embodiment, the inner diameter is substantially the same as the protrusion 42p of the second conductive member 42. The wall 41W is a portion that is pressed by the upper surface 42u of the flange portion 42f when the protrusion 42p of the second conductive member 42 is inserted into the recess 41R of the first conductive member 41. The height of the wall 41W (the depth of the recess 41R) is set to a dimension larger than the height of the protrusion 42p.

[0053] In the fastening step, the first conductive member 41 and the second conductive member 42 are mechanically fastened to each other. In this embodiment, the first conductive member 41 and the second conductive member 42 are mechanically fastened to each other by crimping the first conductive member 41 to the second conductive member 42. As shown in Fig. 5, the first conductive member 41 before being fastened to the second conductive member 42 has a recess 41R in which the protrusion 42p of the second conductive member 42 is disposed. The recess 41R is a portion recessed in a substantially cylindrical shape along the depth direction.

[0054] In the fastening step, first, the first conductive member 41 is placed in a die 70. The dimensions of the inner peripheral surface of the die 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 preferable that the die 70 has a shape that surrounds the entire outer peripheral edge 41o of the first conductive member 41.

[0055] Next, the second conductive member 42 is fastened to the first conductive member 41 arranged in the mold 70. In this embodiment, the second conductive member 42 is pressed against the first conductive member 41 so that the protruding portion 42p of the second conductive member 42 is inserted into the recessed portion 41R of the first conductive member 41. At this time, a known pressing device (not shown) or the like may be used. During pressing, since the wall portion 41W is higher than the protruding portion 42p, the wall portion 41W of the first conductive member 41 is pressed by the upper surface 42u of the flange portion 42f of the second conductive member 42. At this time, since the first conductive member 41 has a lower rigidity than the second conductive member 42, the first conductive member 41 is crushed and plastically deformed.

[0056] 5 and 6, the wall portion 41W of the first conductive member 41 is plastically deformed toward the constricted portion 42n of the second conductive member 42. This causes a part of the first conductive member 41 to flow toward the constricted portion 42n of the second conductive member 42. As a result, as shown in FIG. 6, the edge of the recess 41r of the first conductive member 41 is press-fitted into the constricted portion 42n of the second conductive member 42, and the first conductive member 41 and the second conductive member 42 are fastened together. In the fastening step, as described above, various fastening methods can be used to mechanically fasten the first conductive member 41 and the second conductive member 42 together.

[0057] After the first conductive member 41 and the second conductive member 42 are fastened together to form the fastening portion 43, the first conductive member 41 and the second conductive member 42 are then metal-jointed.

[0058] In the metal joining process, a metal joint 45 is formed at the interface between the first conductive member 41 and the second conductive member 42 on the inner circumferential side of the fastening portion 43. In this embodiment, the first conductive member 41 and the second conductive member 42 are metal-joined by an ultrasonic joint. Although detailed illustration is omitted, in the metal joining process, the fastened first conductive member 41 and the second conductive member 42 are sandwiched between a horn and an anvil, and ultrasonic vibration is applied to the joining interface via the horn. For example, an anvil may be inserted into the cylindrical portion 42c2 of the second conductive member 42, and ultrasonic vibration may be applied to the first conductive member 41 while pressing the horn against the approximate center of the second surface 41b of the first conductive member 41. As a result, a metal joint 45 (see FIG. 3) is formed at the approximate center of the interface between the recess 41r of the first conductive member 41 and the protrusion 42p of the second conductive member 42. In the metal bonding step, as described above, various bonding methods can be used to bond the first conductive member 41 and the second conductive member 42 by metallurgical bonding.

[0059] <Method of Manufacturing Electricity Storage Device 100> The energy storage device 100 can be manufactured using a terminal (in this embodiment, the negative electrode terminal 40) manufactured by the manufacturing method for a terminal for an energy storage device described above. The manufacturing method for the energy storage device 100 includes an insertion step and a crimping step. The manufacturing method for the energy storage device 100 may also include a preparation step of preparing a terminal for a storage battery.

[0060] First, the negative electrode terminal 40 can be prepared by the manufacturing method for a terminal for an electricity storage device described above. Then, the electrode body 10, the exterior 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.

[0061] 3, in the insertion step, the connection portion 42c of the second conductive member 42 is inserted into the opening 14h of the negative current collecting member 14. Also, in the insertion step, the negative terminal 40 is inserted into the terminal attachment hole 24h of the case 20 (in this embodiment, the sealing plate 24). At this time, a gasket 50 and an insulator 60 are arranged on the sealing plate 24.

[0062] In the insertion step, the cylindrical portion 51 of the gasket 50, the opening 14h of the negative current collecting member 14, the terminal mounting hole 24h of the sealing plate 24, and the hole 60h of the insulator 60 are aligned with each other, and the connection portion 42c of the second conductive member 42 is inserted into the opening 14h and the terminal mounting hole 24h. As a result, the connection portion 42c of the negative terminal 40 protrudes from the sealing plate 24 on the surface opposite to the surface on which the flange portion 42f is disposed. In this embodiment, the solid portion 42c1 of the connection portion 42c is inserted into the terminal mounting hole 24h of the sealing plate 24. At least a part of the cylindrical portion 42c2 of the connection portion 42c protrudes from the opening 14h of the negative current collecting member 14. The positive terminal 30 is also inserted into the opening of the sealing plate 24 in the same manner.

[0063] After the insertion step, a crimping step is performed. FIG. 7 is a schematic diagram showing the crimping step. In FIG. 7, a cross section of the negative terminal 40 is shown. In FIG. 7, the connection portion 42c before being deformed by the punch 91 is shown by a dashed line, and the connection portion 42c after being deformed by the punch 91 is shown by a solid line. In FIG. 7, the sealing plate 24, the gasket 50, the insulator 60, and the negative current collecting member 14 are omitted. In the crimping step, the connection portion 42c of the second conductive member 42 is crimped onto the negative current collecting member 14.

[0064] Here, the second conductive member 42 of the negative terminal 40 is crimped onto the negative current collecting member 14. The cylindrical portion 42c2 protruding from the opening 14h of the negative current collecting member 14 is crimped onto the negative current collecting member 14 so that a compressive force is applied in the up-down direction Z. The crimping is performed in a state where a gasket 50 is sandwiched between the negative terminal 40 and the sealing plate 24, and an insulator 60 is further sandwiched between the sealing plate 24 and the negative current collecting member 14.

[0065] As shown in FIG. 7, in the crimping process, a crimping device including a punch (press jig) 91 and a die (receiving jig) 92 may be used. The punch 91 may have any shape that can deform the connection portion 42c of the second conductive member 42. The shapes of the punch 91 and the die 92 are appropriately set depending on the shapes of the first conductive member 41 and the second conductive member 42. In this embodiment, the punch 91 has a substantially truncated cone shape whose tip is narrower than the inner peripheral surface of the cylindrical portion 42c2. The die 92 may have a placement surface that conforms to the shape of the negative terminal 40. The negative terminal 40 is placed on the die 92. Here, the second surface 41b of the first conductive member 41 opposite to the side on which the second conductive member 42 is placed is placed on the die 92.

[0066] Next, the tip of the punch 91 is inserted into the connection portion 42c (preferably the cylindrical portion 42c2) of the second conductive member 42. The side peripheral surface of the punch 91 comes into contact with the cylindrical portion 42c2, and the cylindrical portion 42c2 is pushed outward and expanded. The tip of the connection portion 42c is plastically deformed and expanded in diameter. As a result, the crimped portion 40c is formed in the negative electrode terminal 40, and each member is crimped and fixed. The positive electrode terminal 30 is similarly crimped and fixed to the opening of the sealing plate 24.

[0067] As described above, the positive electrode terminal 30 and the negative electrode terminal 40 are fixed to the sealing plate 24 by the insertion step and the crimping step, as shown in FIG. 3. Then, the electrode body 10 integrated with the sealing plate 24 by a known method is housed in the exterior body 22. The sealing plate 24 is joined to the periphery of the opening 22h of the exterior body 22. The joining is performed by a conventionally known method (for example, laser welding). The electrolyte is poured from the liquid pouring hole, and the liquid pouring hole is closed to hermetically seal the electricity storage device 100. In this manner, the electricity storage device 100 can be manufactured.

[0068] Incidentally, when the terminal for the electric storage device is attached to the electric storage device, the terminal for the electric storage device is inserted into a terminal mounting hole of a sealing plate and fixed by crimping. At this time, a conductive member, an electrode body, etc. are attached to the sealing plate. When the electrode body, etc. are attached to the sealing plate, it is difficult to post-process the terminal for the electric storage device after the terminal for the electric storage device is fixed by crimping to the sealing plate from the viewpoint of workability. For example, when a terminal for the electric storage device in which a plurality of conductive members are mechanically fastened and metal-joined is used as the terminal for the electric storage device, the terminal for the electric storage device needs to be prepared in advance. However, according to the trial of the present inventor, when a terminal for the electric storage device composed of a plurality of conductive members is prepared in advance and fixed by crimping to the sealing plate, there are cases where the joint between the members constituting the terminal for the electric storage device is not well maintained. When the terminal for the electric storage device is fixed to the sealing plate by crimping, an event has been confirmed in which a portion other than the connection portion of the terminal for the electric storage device is also plastically deformed.

[0069] In the negative electrode terminal 40 described above, the fastening portion 43 is located on the outer periphery side of the metal joint portion 45 in the first conductive member 41. In the negative electrode 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 approximately the same position in the radial direction of the flange portion 42f. In this case, the amount of the first conductive member 41 relative to the second conductive member 42 is smaller than in a case where the first conductive member covers the periphery of the flange portion of the second conductive member. This suppresses the amount of deformation of the entire first conductive member 41 that deforms in association with the deformation of the connection portion 42c of the second conductive member 42. As a result, the amount of deformation on the radial inner side of the fastening portion 43 can also be suppressed. As a result, the metal joint portion 45 on the radial inner side of the fastening portion 43 is easily maintained. In addition, even when the first conductive member 41 deforms, the first conductive member 41 is easily deformed toward the radial outer side along the flange portion 42f. This can reduce the amount of deformation radially inward from the fastening portion 43. As a result, the metal joint 45 is more likely to be maintained, and the electrical continuity reliability of the negative electrode terminal 40 can be improved.

[0070] 3, an insulating member (resin member) such as a gasket 50 is preferably disposed so as to face the boundary between the outer circumferential edge 41o of the first conductive member 41 and the outer circumferential edge 42fo of the flange portion 42f of the second conductive member 42. The insulating member such as the gasket 50 preferably extends from a region in contact with the sealing plate 24 to a position facing the outer circumferential edge 41o of the first conductive member 41. This makes it possible to prevent water and the like from adhering across the first conductive member 41 and the second conductive member 42. This makes it possible to more effectively prevent the terminals from corroding.

[0071] It is preferable that the first conductive member 41 has a substantially circular shape in a plan view, and the flange portion 42f of the second conductive member 42 has a substantially circular shape in a plan view.

[0072] Furthermore, a load is likely to be applied to a region (first region A1) of the first conductive member 41 that corresponds to the connection portion 42c that is deformed in the second conductive member 42. In this case, the outer side is more likely to deform than the first region A1. This makes it difficult for the first conductive member 41 to deform in the second region A2 that is more inward than the first region A1. As a result, the metal joint 45 is more likely to be maintained, and the electrical conductivity reliability of the negative electrode terminal 40 can be improved.

[0073] In this embodiment, an annular rib 41ri is formed on the second surface 41b of the first conductive member 41 between the first region A1 and the second region A2. The rib 41ri is formed on the outside of the second region A2. The rib 41ri is formed to partially overlap with an inner region of the first region A1. By providing the rib 41ri, deformation of the second region A2 is easily suppressed. As a result, the load on the metal joint 45 is easily reduced. The rib 41ri is not necessarily provided.

[0074] The above-described effect can be greater as the thickness of the first region A1 is thinner. For example, as the thickness of the first region A1 is thinner, the suppression of deformation of the second region A2 is suppressed, and also when an external conductive member 48, a bus bar 90 (see FIG. 4), etc. are welded to the rib 41ri, the load applied to the metal joint 45 can be reduced. From such a viewpoint, the thickness of the first region A1 is preferably 1.5 mm or less, and more preferably 0.8 mm or less.

[0075] Note that the usage form of the rib 41ri is not particularly limited. A bus bar 90 may be welded to the rib 41ri, or the bus bar 90 may be welded outside the rib 41ri. Also, an external conductive member 48 may be welded and joined to the rib 41ri. Thereby, it can be suppressed that the welded portion of the external conductive member 48 and the first conductive member 41 reaches the second conductive member 42. As a result, the reliability of the welded portion can be good.

[0076] Also, from the viewpoint of suppressing deformation of the second region A2, in the first conductive member 41, it is preferable that the first region A1 and the second region A2 have substantially the same thickness. When the thickness of the first region A1 is T1 and the thickness of the second region A2 is T2, it is preferable to satisfy 0.8 < T1 / T2 < 1.2, and more preferably to satisfy 0.9 < T1 / T2 < 1.1. Also, the thickness of the first region A1 is particularly preferably thinner. For example, it is preferably 1.5 mm or less, and more preferably 0.8 mm or less. Also, when the thickness of the flange portion 42f of the second conductive member 42 is T3, T1 / T3 is preferably 1 / 3 or less. By being set to such dimensions, the first conductive member 41 can easily extend outward along the flange portion 42f of the second conductive member 42, and deformation of the second region A2 can be suppressed. Note that the above-described thicknesses of the first region A1 and the second region A2 are the thicknesses of the portions excluding the rib 41ri, and are the thicknesses between the upper surface 42u and the bottom 41r2 of the recess 41r.

[0077] In the above-described embodiment, the first region A1 and the second region A2 are contained in the region in which the recess 41r is formed in a plan view. However, the positional relationship between the first region A1, the second region A2, and the recess 41r is not limited to this form. FIG. 8 is a cross-sectional view of a negative electrode terminal 140 according to another embodiment. In FIG. 8, the configuration common to the above-described negative electrode terminal 40 is given the same reference numerals, and detailed description is omitted. As shown in FIG. 8, the recess 141r of the first conductive member 141 is formed at a position overlapping the first region A1 in a plan view. The opening 141r1 of the recess 141r is provided at a position overlapping the first region A1. In the first region A1, the first surface 141a of the first conductive member 41 is thicker than the bottom 141r2 of the recess 141r. Even in this case, it is preferable that the difference in height between the upper surface of the first region A1 and the upper surface of the second region A2 is 2 mm or less.

[0078] The relationship between the thickness T1 of the first region A1 and the thickness T2 of the second region A2 described above may vary depending on the configuration of the first conductive member 41 and the second conductive member 42 (see FIG. 7). In the embodiment shown in FIG. 8, when the thickness of the first region A1 (thickness between the first surface 141a and the second surface 141b of the first conductive member 41) is T11 and the thickness of the second region A2 (thickness between the bottom 141r2 of the recess 141r and the second surface 141b) is T12, it is preferable that T11>T12 is satisfied, more preferably that T11 / T12>1.1 is satisfied, and further preferably that T11 / T12>1.2 is satisfied. Such a relationship between the thickness T11 of the first region A1 and the thickness T12 of the second region A2 makes it easier to suppress deformation of the second region A2 and easier to maintain the bonding of the metal bonding portion 45.

[0079] The technology disclosed herein has been described above in various ways. Unless otherwise specified, the embodiments and the like described herein do not limit the present invention. Furthermore, the technology disclosed herein can be modified in various ways, and each component and each process described herein can be omitted or combined as appropriate, unless a particular problem occurs. [Explanation of symbols]

[0080] 10 Electrode body 11 Positive electrode current collector 12 Negative electrode current collector 13 Positive electrode current collector 14 Negative electrode current collecting member 14f Flat plate part 14h opening 20 cases 22 Exterior body 22d bottom 22h opening 24 Sealing plate 24h Terminal mounting hole 30 Positive terminal 40,140 Negative terminal 40c Crimping part 41,141 First conductive member 41a 1st page 41b 2nd side 41o Outer rim 41r Recess 41r1 opening 41r2 bottom 41ri Rib 41R Recess 41W wall 42 Second conductive member 42c Connection 42c1 Solid part 42c2 Cylindrical part 42d Bottom surface 42e Expanded section 42f Flange 42fo Outer rim 42n Neck 42p protrusion 42u top 43 Fastening Part 45 Metal joints 48 External conductive members 50 Gasket 60 Insulator 70 Mold 90 Busbar 91 Punch 92 Die 100 Electricity storage device 200 battery pack A1 1st area Area 2 of A2

Claims

1. an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; A case that houses the electrode assembly; a terminal electrically connected to the first electrode and attached to the case; a current collecting member disposed within the case and electrically connecting the first electrode and the terminal; Equipped with the terminal includes a first conductive member made of a first metal and a second conductive member made of a second metal different from the first metal; the first conductive member has a recess on a first surface; A portion of the second conductive member is disposed within the recess, the first conductive member has a fastening portion that is mechanically fastened to the second conductive member and a metal joint portion that is metal-jointed to the second conductive member, In the first conductive member, the fastening portion is located on an outer circumferential side relative to the metal joint portion. A power storage device, the second conductive member has a flange portion and a connection portion formed on one surface of the flange portion, A tip of the connection portion has an expanded diameter portion, and the expanded diameter portion is connected to the current collecting member, A portion of the flange is disposed within the recess; an outer circumferential edge of the first conductive member and an outer circumferential edge of the flange portion are located at substantially the same position in a radial direction of the flange portion; Energy storage device.

2. the first conductive member has a first region that is a region overlapping with the enlarged diameter portion when viewed in a direction in which the connection portion extends, and a second region that is located more inward than the first region, The power storage device according to claim 1 , wherein 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. an outer conductive member; The power storage device according to claim 3 , wherein 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 first conductive member made of a first metal; and a second conductive member made of a second metal different from the first metal; the first conductive member has a recess on a first surface; a portion of the second conductive member is disposed within the recess; the first conductive member has a fastening portion that is mechanically fastened to the second conductive member and a metal joint portion that is metal-jointed to the second conductive member, In the first conductive member, the fastening portion is located on an outer circumferential side relative to the metal joint portion. A terminal for an electric storage device, the second conductive member has a flange portion and a connection portion formed on one surface of the flange portion, The tip of the connection portion has an expanded diameter portion, A portion of the flange is disposed within the recess; an outer circumferential edge of the first conductive member and an outer circumferential edge of the flange portion are located at substantially the same position in a radial direction of the flange portion; Terminal for power storage device.

7. an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; A case that houses the electrode assembly; a terminal electrically connected to the first electrode and attached to the case; a current collecting member disposed within the case and electrically connecting the first electrode and the terminal; Equipped with the terminal includes a first conductive member made of a first metal and a second conductive member made of a second metal different from the first metal; the first conductive member has a recess on a first surface; a portion of the second conductive member is disposed within the recess; the first conductive member has a fastening portion that is mechanically fastened to the second conductive member and a metal joint portion that is metal-jointed to the second conductive member, A method for manufacturing an electric storage device, wherein in the first conductive member, the fastening portion is located on an outer circumferential side of the metal joint portion, the second conductive member has a flange portion and a connection portion formed on one surface of the flange portion, A tip of the connection portion has an expanded diameter portion, and the expanded diameter portion is connected to the current collecting member, A portion of the flange is disposed within the recess; an outer circumferential edge of the first conductive member and an outer circumferential edge of the flange portion are located at substantially the same position in a radial direction of the flange portion, an insertion step of inserting the connection portion of the second conductive member into an opening of the current collecting member; a crimping step of crimping the connection portion onto the current collecting member after the insertion step; A method for manufacturing an electricity storage device comprising the steps of:

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