Electricity storage device, terminal for electric power storage device, and method for manufacturing electric 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 the electricity storage device, and a method for manufacturing the electricity storage device. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2022-049726 discloses a terminal including a plate-shaped metal first member and a metal second member ultrasonically welded to one surface of the first member. The first member has a recess formed on the surface 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] Japanese Patent Publication No. 2022-049726 Summary of the Invention [Problem to be solved by the invention]

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

[0005] The electricity storage device disclosed herein includes an electrode assembly, a case that houses the electrode assembly, a terminal, and a current collecting member. The electrode assembly includes a first electrode and a second electrode having a polarity opposite to that of the first electrode. The case houses the electrode assembly. The terminal is electrically connected to the first electrode and attached to the case. The current collecting member is disposed within 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 its first surface. A portion of the second conductive member is disposed within 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. The outer circumferential edge of the first conductive member and the outer circumferential edge of the flange are located at substantially the same position in the radial direction of the flange.

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

[0007] [Figure 1] FIG. 1 is a perspective view of the electricity storage device 100. As shown in FIG. [Figure 2] FIG. 2 is a schematic vertical cross-sectional view taken along line II-II in FIG. [Figure 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. [Figure 5] FIG. 5 is a cross-sectional view showing the first conductive member 41 and the second conductive member 42 before they are fastened together in the fastening step. [Figure 6] FIG. 6 is a cross-sectional view showing the first conductive member 41 and the second conductive member 42 after they have been fastened together 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 INVENTION

[0008] An embodiment of the technology disclosed herein will be described below with reference to the drawings. The embodiments described herein are, of course, not intended to limit the present invention. The drawings are schematic and do not necessarily reflect the actual product. Furthermore, identical reference numerals are used to designate components and parts that perform the same function, and redundant descriptions will be omitted where appropriate. 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 power storage device, respectively. However, these directions are merely used for convenience of description and do not in any way limit the installation form of the power storage device.

[0009] In this specification, the term "electricity storage device" refers to a general electricity storage device capable of extracting electrical 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 in which a lithium ion secondary battery is used.

[0010] <Electricity storage device 100> FIG. 1 is a perspective view of an energy storage device 100. FIG. 2 is a schematic longitudinal cross-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 cross-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 energy storage devices 100 disclosed herein are connected in series via bus bars 90, each serving as a single cell.

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

[0012] The electrode assembly 10 may be the same as a conventional one and is not particularly limited. The electrode assembly 10 includes a positive electrode and a negative electrode (not shown). The electrode assembly 10 is, for example, a flat wound electrode assembly 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 assembly 10 may be a laminated electrode assembly 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 (e.g., a lithium transition metal composite 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 (e.g., 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 electrode body 10 in the long side direction X, where a positive electrode mixture layer and a negative electrode mixture layer are laminated in an insulated state. Meanwhile, at the left end of the electrode body 10 in the long side direction X, a portion of the positive electrode current collector 11 where no positive electrode mixture layer is formed (exposed positive electrode current collector portion) protrudes from the laminated portion. A positive electrode current collector member 13 is attached to the exposed positive electrode current collector portion. The positive electrode current collector member 13 may be made of the same metal material as the positive electrode current collector 11, such as a conductive metal such as aluminum, an aluminum alloy, nickel, or stainless steel. The positive electrode current collector member 13 is disposed within the case 20. The positive electrode current collector member 13 electrically connects the positive electrode to the positive electrode terminal 30.

[0015] Furthermore, at the right end of the electrode assembly 10 in the long side direction X, a portion of the negative electrode current collector 12 on which the negative electrode mixture layer is not formed (negative electrode current collector exposed portion) protrudes from the laminated portion. A negative electrode current collector 14 is attached to the negative electrode current collector exposed portion. 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 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 within 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 conventional ones and is not particularly limited. The electrolyte is, for example, a non-aqueous liquid electrolyte (nonaqueous electrolytic solution) 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, a fluorine-containing lithium salt such as LiPF6. However, the electrolyte may be a solid (solid electrolyte) and integrated with the electrode assembly 10.

[0017] The case 20 is a housing that houses the electrode assembly 10. Here, the case 20 is formed in a flat, bottomed rectangular parallelepiped (rectangular) shape. However, the shape of the case 20 is not limited to a rectangular shape and may be any shape, such as a cylindrical shape. The material of the case 20 is not particularly limited and may be the same as that conventionally used. 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 (e.g., 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] Exterior body 22 has a bottom surface 22d. Sealing plate 24 faces bottom surface 22d of exterior body 22. Sealing plate 24 is attached to exterior body 22 so as to close opening 22h of exterior body 22. Here, sealing plate 24 has a substantially rectangular shape. Note that in this specification, the term "substantially rectangular shape" encompasses not only a perfect rectangular shape (rectangular shape), but also shapes in which, for example, corners connecting the long and short sides of a rectangle are rounded, or shapes in which the corners have cutouts.

[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 assembly 10 via a positive electrode current collector 13 inside the case 20. The negative electrode terminal 40 is electrically connected to the negative electrode of the electrode assembly 10 via a 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). The positive electrode terminal 30 and the negative electrode terminal 40 are preferably 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 via 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 energy 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. Note that 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, "negative electrode" can be read as "positive electrode" as appropriate.

[0022] As shown in FIG. 3, the sealing plate 24 is formed with a terminal mounting hole 24h that penetrates in the up-down direction Z. The terminal mounting hole 24h is provided in the case 20 (in this embodiment, the sealing plate 24). 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 here has a circular shape (for example, a perfect circle) in a plan view. The terminal mounting hole 24h has an inner diameter large enough to allow the insertion of a connecting 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 collector 14 is attached to the exposed portion of the negative current collector 12 and forms a conductive path electrically connecting the negative electrode and the negative terminal 40. The negative current collector 14 has a flat portion 14f that extends 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 allow the insertion of the connection portion 42c of the negative terminal 40 before crimping, which will be described later. The negative current collector 14 is fixed to the sealing plate 24 together with the negative terminal 40 by crimping. A resin insulating member is preferably disposed between the case 20 (in this embodiment, the sealing plate 24) and the negative current collector 14. In this embodiment, the negative current collector 14 is fixed to the sealing plate 24 together with the negative terminal 40 in a state of being insulated via an 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., the gasket 50) is preferably disposed between the case 20 (e.g., the sealing plate 24) and the negative electrode terminal 40. Here, the gasket 50 serves to insulate the sealing plate 24 from the negative electrode terminal 40 and also to close 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 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 51h that penetrates in the vertical direction Z. The hole 51h is formed so that the connection portion 42c of the negative electrode terminal 40 can be inserted therethrough before crimping. The tubular portion 51 is inserted into a terminal mounting hole 24h of the sealing plate 24. The base portion 52 prevents direct contact between the sealing plate 24 and a flange portion 42f of the negative electrode terminal 40, which will be described later. The base portion 52 is connected to the upper end of the tubular portion 51. The base portion 52 extends horizontally from the upper end of the tubular portion 51. The base portion 52 is formed, for example, in a 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 extends 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 allow the connection portion 42c of the negative electrode terminal 40 to be inserted therethrough. The insulator 60 is made of an elastically deformable resin material that is resistant to the electrolyte used and electrically insulating, such as a fluorinated resin such as perfluoroalkoxy fluorine resin (PFA) or polyphenylene sulfide resin (PPS). 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 member 14, and is compressed in the vertical direction Z by caulking.

[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 outside the case 20.

[0028] As will be described later, 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 electrode terminal 40 is inserted into the terminal mounting hole 24h of the sealing plate 24 and the opening 14h of the negative electrode current collecting member 14, and its leading end (a cylindrical portion 42c2, described later) in the insertion direction is crimped onto the negative electrode current collecting member 14. More specifically, the leading end is crimped to the peripheral portion surrounding the opening 14h of the negative electrode current collecting member 14. A crimped portion 40c is formed at the lower end of the negative electrode terminal 40. The negative electrode terminal 40 is fixed to the sealing plate 24 and electrically connected to the negative electrode current collecting member 14 by crimping. In this example, the crimped portion 40c is cylindrical. 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 be welded to the negative electrode current collecting member 14. The first conductive member 41 and the second conductive member 42 constituting the negative electrode 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. Here, the first conductive member 41 is made of aluminum. The first conductive member 41 is preferably made of a metal that has a lower Vickers hardness (is 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 that has the same metal element as the first component (the component with the highest mass ratio; the same applies below).

[0031] In this embodiment, the first conductive member 41 is plate-shaped (more 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 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 its diameter increases from the opening 41r1 to the bottom 41r2. The side surface of the recess 41r tapers so that its 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. In this example, 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 containing the same metal element as the first component. 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 connecting portion 42c. The flange portion 42f is a portion of the second conductive member 42 that has a larger diameter in the planar directions (X direction and Y direction) compared to other portions. The flange portion 42f is a portion that is disposed outside the case 20. The flange portion 42f is connected to the first conductive member 41. The connecting 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 cylindrical portion 51 of the gasket 50 is disposed between the connecting 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 approximately the same position in the radial direction of the flange portion 42f. For example, 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 in the radial direction of the flange portion 42f may be within 2 mm. The smaller the dimension by which one protrudes from the other, the better, and it is more preferable that it be within 1 mm, and even more preferably within 0.5 mm. In this embodiment, the flange portion 42f is generally disk-shaped with dimensions approximately the same as the dimensions of 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 seen 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 the upper surface 42u of the flange portion 42f. The protruding portion 42p has a shape that follows the recess 41r. The diameter of the protruding portion 42p increases toward the tip side (the side farther from the flange portion 42f). The diameter of the protruding portion 42p decreases from the tip 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 the recess 41r of the first conductive member 41. The first conductive member 41 is connected to the second conductive member 42 by a mechanically fastened fastening portion 43. The form of the fastening portion 43 is not particularly limited as long as it is mechanically fastened by, for example, 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 preferably has a recess formed in the outer peripheral side wall of the flange portion 42f of the second conductive member 42, with a portion of the first conductive member 41 disposed within the recess. In this embodiment, a constricted portion 42n serving as a recess is formed in the outer peripheral 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 constricted portion 42n of the second conductive member 42. A portion of the inner wall of the first recess 41r of the first conductive member 41 extends into the constricted portion 42n of the second conductive member 42. This allows the inner wall of the first recess 41r of the first conductive member 41 to be fixed (e.g., pressed) by the constricted portion 42n of the second conductive member 42. In this manner, the protruding portion 42p fits into the recess 41r. As a result, the first conductive member 41 and the second conductive member 42 are mechanically fastened together. 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, metallic joining refers to a portion where multiple 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 brittle intermetallic compounds at the joining interface, the metal joint 45 is preferably an ultrasonic joint formed by ultrasonic joining. In this embodiment, the metal joint 45 is an ultrasonic joint where the first conductive 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 periphery 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 a connecting portion 42c of the second conductive member 42 (described later) extends. The second region A2 is located more inward than the first region A1. Other regions, such as a region in which a rib 41ri (described later) is formed, may be provided between the first region A1 and the second region A2. In this embodiment, the extending direction of the connecting portion 42c corresponds to the thickness direction of a portion (sealing plate 24) of the case 20 in which 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, in a plan view along the extension direction of the connecting portion 42c, the first region A1 and the second region A2 are located inside the region in which the recess 41r is formed. 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 flush with each other. 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 approximately the center of the bottom 41r2 of the recess 41r of the first conductive member 41. Because the metal joint portion 45 is formed in approximately the 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 load due to vibrations 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 of the flange portion 42f (in this embodiment, the lower surface 42d). 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 connected to the negative current collecting member 14 by crimping. From the viewpoint of improving conductivity, the expanded diameter portion 42e and a portion of the negative current collecting member 14 are preferably 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 that constitutes the crimped portion 40c of the negative 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 approximately the center of the lower surface 42d of the flange portion 42f. The solid portion 42c1 extends toward the tip side of the connection portion 42c. The cylindrical portion 42c2 is a substantially cylindrical portion that extends from the solid portion 42c1 toward the tip side before being connected to the negative current collecting member 14. The diameter of the cylindrical portion 42c2 is expanded when connected to the negative current collecting member 14, and a portion of the expanded diameter portion 42e is crimped onto the negative current collecting member 14 and connected to the negative current collecting member 14.

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

[0046] In the negative electrode terminal 40 described above, a portion of the interface between the first conductive member 41 and the second conductive member 42 is metal-jointed by a metal joint 45. This reduces the electrical resistance between the first conductive member 41 and the second conductive member 42. As a result, electrical continuity 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 a fastening portion 43 located on the outer periphery side of the metal joint 45. This firmly connects the first conductive member 41 and the second conductive member 42. As a result, the metal joint 45 is easily maintained, and good electrical continuity 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 configured as described above, the dimensions of the second conductive member 42 can be made approximately the same as the dimensions 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. The increased diameter of the fastening portion 43 increases the bonding strength of the fastening portion 43. As a result, the metal joint 45 is more likely to be maintained, and good conductivity between the first conductive member 41 and the second conductive member 42 is more likely to be maintained. Furthermore, the increased proportion of the second conductive member 42 in the negative electrode terminal 40 can improve the conductivity between the first conductive member 41 and the second conductive member 42. As a result, heat generation due to current flow is suppressed, and the durability of the energy storage device 100 can be improved.

[0048] <Method of manufacturing negative electrode terminal 40> The above-described negative electrode terminal 40 can be manufactured, for example, by the manufacturing method of a terminal for an electric storage device (in this embodiment, the negative electrode terminal 40) described below. The manufacturing method of the terminal for an electric 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 together. The manufacturing method of the terminal for an electric 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 have been 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 plastically deforms 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 shape described above is prepared as the second conductive member 42. In this embodiment, a metal having 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 constricted portion 42n of the second conductive member 42 when it is crimped in the fastening step. In this embodiment, the first conductive member 41 is prepared, which has a recess 41R and a wall portion 41W (see FIG. 5). The recess 41R is a portion that becomes the recess 41r after the second conductive member 42 is placed therein.

[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 is, for example, preferably 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 it is a dimension that allows the protrusion 42p of the second conductive member 42 to be inserted therein. In this embodiment, it is approximately 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 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 greater 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 together. In this embodiment, the first conductive member 41 and the second conductive member 42 are mechanically fastened together 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 process, first, the first conductive member 41 is placed in a mold 70. The dimensions of the inner peripheral surface of the mold 70 correspond to the dimensions of the outer peripheral edge 41o of the first conductive member 41 and the outer peripheral edge 42fo of the flange portion 42f. From the viewpoint of suppressing unnecessary deformation of the first conductive member 41, it is preferable that the mold 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 placed 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, the first conductive member 41, which has lower rigidity than the second conductive member 42, 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 portion 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-fit into the constricted portion 42n of the second conductive member 42, fastening the first conductive member 41 and the second conductive member 42 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-joined.

[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 using an ultrasonic welding unit. Although detailed illustration is omitted, in the metal joining process, the fastened first conductive member 41 and second conductive member 42 are sandwiched between a horn and 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 approximately the 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 approximately the center of the interface between the recess 41r of the first conductive member 41 and the protrusion 42p of the second conductive member 42. As described above, in the metal joining step, various joining methods can be used to join the first conductive member 41 and the second conductive member 42 by metallurgical joining.

[0059] <Method of Manufacturing the Power 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 above-described method for manufacturing a terminal for an energy storage device. The method for manufacturing the energy storage device 100 includes an insertion step and a crimping step. The method for manufacturing 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 assembly 10, the exterior body 22 of the case 20, and the sealing plate 24 can be prepared. The electrode assembly 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 using a known method.

[0061] 3, in the insertion step, the connecting 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 mounting 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 through 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 side opposite to the side 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 portion 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 similarly inserted into the opening of the sealing plate 24.

[0063] After the insertion step, the crimping step is carried out. FIG. 7 is a schematic diagram illustrating the crimping step. FIG. 7 schematically illustrates a cross section of the negative electrode terminal 40. In FIG. 7, the connection portion 42c before being deformed by the punch 91 is indicated by a dashed line, and the connection portion 42c after being deformed by the punch 91 is indicated by a solid line. In FIG. 7, the sealing plate 24, the gasket 50, the insulator 60, and the negative electrode current collecting member 14 are not illustrated. In the crimping step, the connection portion 42c of the second conductive member 42 is crimped onto the negative electrode 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 vertical direction Z. The crimping is performed with the gasket 50 sandwiched between the negative terminal 40 and the sealing plate 24, and with the insulator 60 sandwiched between the sealing plate 24 and the negative current collecting member 14.

[0065] As shown in FIG. 7 , the crimping process may use a crimping device including a punch (press jig) 91 and a die (receiving jig) 92. The punch 91 may have any shape as long as it 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 generally truncated cone shape with its tip 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 electrode terminal 40. The negative electrode terminal 40 is placed on the die 92. Here, the second surface 41b of the first conductive member 41, which is 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 connecting portion 42c (preferably the cylindrical portion 42c2) of the second conductive member 42. The side peripheral surface of the punch 91 contacts the cylindrical portion 42c2, expanding the cylindrical portion 42c2 outward. The tip of the connecting portion 42c is plastically deformed and expands in diameter. As a result, a crimped portion 40c is formed in the negative electrode terminal 40, and the various components are 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 through the insertion process and the crimping process, as shown in FIG. 3. Next, the electrode body 10 integrated with the sealing plate 24 is housed in the exterior body 22 by a known method. 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 through 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] When attaching a power storage device terminal to a power storage device, the power storage device terminal is inserted into a terminal mounting hole in a sealing plate and crimped. At this time, a conductive member, an electrode assembly, and the like are attached to the sealing plate. When an electrode assembly, etc., is attached to the sealing plate, it is difficult to post-process the power storage device terminal after crimping it to the sealing plate from the standpoint of workability. For example, when a power storage device terminal is used in which multiple conductive members are mechanically fastened and metal-bonded, the power storage device terminal needs to be prepared in advance. However, according to trials by the present inventors, when a power storage device terminal composed of multiple conductive members is prepared in advance and crimped to the sealing plate, the bond between the components constituting the power storage device terminal may not be maintained properly. It has been confirmed that when crimping the power storage device terminal to the sealing plate, plastic deformation also occurs in portions other than the connection portion of the power storage device terminal.

[0069] In the negative electrode terminal 40 described above, the fastening portion 43 of the first conductive member 41 is located more radially outward than the metal joint portion 45. In this 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 located 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 configuration in which the first conductive member covers the periphery of the flange portion of the second conductive member. This reduces the amount of deformation of the entire first conductive member 41 that occurs in association with deformation of the connection portion 42c of the second conductive member 42. As a result, the amount of deformation radially inward from the fastening portion 43 can also be reduced. As a result, the metal joint portion 45 radially inward from the fastening portion 43 is more likely to be maintained. Furthermore, even when the first conductive member 41 deforms, the first conductive member 41 is more likely to deform radially outward along the flange portion 42f. This can reduce the amount of deformation radially inside 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 the 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 corrosion of the terminals.

[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 connecting 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. As a result, the first conductive member 41 is less likely 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 outside the second region A2. The rib 41ri is formed so as to partially overlap with an inner region of the first region A1. The provision of the rib 41ri makes it easier to suppress deformation of the second region A2. As a result, the load on the metal joint 45 is more likely to be reduced. Note that the rib 41ri does not necessarily have to be 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 portion 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. The bus bar 90 may be welded to the rib 41ri, or the bus bar 90 may be welded outside the rib 41ri. Also, the 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 the 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 the 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 concave portion 41r.

[0077] In the above-described embodiment, the first region A1 and the second region A2 are contained within 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. FIG. 8 is a cross-sectional view of a negative electrode terminal 140 according to another embodiment. In FIG. 8, components common to the above-described negative electrode terminal 40 are denoted by the same reference numerals, and detailed description thereof will be omitted. As shown in FIG. 8, the recess 141r of the first conductive member 141 is formed in a position overlapping the first region A1 in a plan view. The opening 141r1 of the recess 141r is provided in 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, the difference in height between the top surface of the first region A1 and the top surface of the second region A2 is preferably 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 configurations 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 (the 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 (the thickness between the bottom 141r2 of the recess 141r and the second surface 141b) is T12, it is preferable that T11 > T12, more preferably that T11 / T12 > 1.1, and even more preferably that T11 / T12 > 1.2. This relationship between the thickness T11 of the first region A1 and the thickness T12 of the second region A2 helps to suppress deformation of the second region A2 and maintain the bonding of the metal bonding portion 45.

[0079] The technology disclosed herein has been described 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 the components and processes described herein can be omitted or combined as appropriate, unless a particular problem arises. [Explanation of symbols]

[0080] 10 Electrode body 11 Positive electrode current collector 12 Negative electrode current collector 13 Positive electrode current collecting member 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 Crimped part 41,141 First conductive member 41a 1st page 41b 2nd side 41o outer edge 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 edge 42n Neck 42p protrusion 42u top 43 Fastening part 45 Metal joints 48 External conductive members 50 gaskets 60 insulator 70 molds 90 Busbar 91 Punch 92 Die 100 Electricity storage device 200 battery packs A1 1st area A2, Second Field

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 for accommodating 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 mechanically fastened to the second conductive member and a metal joint portion metal-jointed to the second conductive member, In the first conductive member, the fastening portion is located on an outer circumferential side of the metal joint portion. An electricity 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 portion 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 on both sides of the flange portion in the radial direction; Energy storage device.

2. an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; a case for accommodating 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 mechanically fastened to the second conductive member and a metal joint portion metal-jointed to the second conductive member, In the first conductive member, the fastening portion is located on an outer circumferential side of the metal joint portion. An electricity 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 portion is disposed within the recess; an outer circumferential edge of the first conductive member and an outer circumferential edge of the flange portion are within 0.5 mm in a radial direction of the flange portion; Energy storage device.

3. the first conductive member has a first region that is a region overlapping with the enlarged diameter portion when viewed in the 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.

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

5. an outer conductive member; The power storage device according to claim 4 , wherein the external conductive member is welded to the annular rib.

6. The power storage device according to claim 3 , 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.

7. The connecting portion has a substantially cylindrical tubular portion with the enlarged diameter portion provided at a tip thereof, The power storage device according to claim 1 , wherein the fastening portion is provided at a position overlapping the cylindrical portion when viewed in the extending direction of the connecting portion.

8. 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 mechanically fastened to the second conductive member and a metal joint portion metal-jointed to the second conductive member, In the first conductive member, the fastening portion is located on an outer circumferential side of 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 part has an expanded diameter part, A portion of the flange portion 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 on both sides of the flange portion in the radial direction; Terminal for power storage device.

9. 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 mechanically fastened to the second conductive member and a metal joint portion metal-jointed to the second conductive member, In the first conductive member, the fastening portion is located on an outer circumferential side of 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 part has an expanded diameter part, A portion of the flange portion is disposed within the recess; an outer circumferential edge of the first conductive member and an outer circumferential edge of the flange portion are within 0.5 mm in a radial direction of the flange portion; Terminal for power storage device.

10. an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; a case for accommodating 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 mechanically fastened to the second conductive member and a metal joint portion metal-jointed to the second conductive member, a first conductive member having a fastening portion disposed 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 portion 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 on both sides of the flange portion in a radial direction; 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:

11. an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; a case for accommodating 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 mechanically fastened to the second conductive member and a metal joint portion metal-jointed to the second conductive member, a first conductive member having a fastening portion disposed 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 portion is disposed within the recess; an outer circumferential edge of the first conductive member and an outer circumferential edge of the flange portion are within 0.5 mm of each other 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:

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