Terminal for power storage device and method for manufacturing power storage device provided with same

Abstract

The invention relates to a terminal for a power storage device and a method for manufacturing the power storage device with the terminal for the power storage device, wherein the reliability of a connecting part between a first conductive member and a second conductive member is high. According to the present invention, the terminal is provided with: a first conductive member comprising a first metal and having a recess; a second conductive member made of a second metal and having a portion disposed in the recess; and an ultrasonic bonding portion that ultrasonically bonds the first conductive member and the second conductive member, the first conductive member being provided with a rib that is provided further toward the outer peripheral side than the ultrasonic bonding portion and that protrudes from the second surface of the first conductive member.

Description

Technical Field

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

[0002] In the past, it is known that there are terminals formed by joining conductive parts (a first conductive part and a second conductive part) made of different types of metal. For example, Japanese Patent Application Publication No. 2022-049729 discloses a method for manufacturing a terminal and a method for manufacturing a power storage device as described below, wherein the method for manufacturing the terminal includes: a fastening step of mechanically fixing the first conductive part and the second conductive part to form a fastening portion; and a metal joining step of metal-joining the first conductive part and the second conductive part to form a metal joining portion, and the method for manufacturing the power storage device includes a caulking step of fixing the terminal to the battery case and the current collecting part by caulking.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2022-049729

[0004] For example, in mechanical joining processes such as the tightening process and the caulking process, loads are sometimes applied to the conductive component and the metal joint. Therefore, it is conceivable that the conductive component is deformed or the metal joint is damaged, which makes it difficult to stabilize the connection state between the first conductive component and the second conductive component. In particular, when the first conductive component and the second conductive component are ultrasonically joined to form an ultrasonic joint in the metal joining process, this tendency is significant because ultrasonic joining is preferably performed before the caulking process. Summary of the invention

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a terminal for a power storage device having an ultrasonic bonding portion and a highly reliable connection portion between a first conductive member and a second conductive member, and a method for manufacturing a power storage device having the terminal for a power storage device.

[0006] According to the present invention, there is provided a terminal for a power storage device, comprising: a first conductive component, which is made of a first metal and has a recessed portion on a first surface; a second conductive component, which is made of a second metal different from the first metal and has a portion arranged in the recessed portion; and an ultrasonic bonding portion, which ultrasonically bonds the first conductive component to the second conductive component, wherein the first conductive component has a rib, which is arranged closer to the outer periphery than the ultrasonic bonding portion and protrudes from a second surface of the first conductive component on the opposite side of the first surface.

[0007] According to the above configuration, the connection portion between the first conductive member and the second conductive member can be a terminal with high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a perspective view schematically showing a power storage device according to an embodiment.

[0009] Figure 2 It is along Figure 1 Schematic longitudinal cross-sectional view along line II-II.

[0010] Figure 3 It is a partial enlarged cross-sectional view schematically showing the vicinity of the negative electrode terminal.

[0011] Figure 4 It is a plan view schematically showing a negative electrode terminal according to one embodiment.

[0012] Figure 5 It is along Figure 4 Schematic longitudinal cross-sectional view of line V-V.

[0013] Figure 6 It is a longitudinal sectional view schematically showing the connection between the negative electrode terminal and the external conductive member.

[0014] Figure 7 It is a perspective view schematically showing a power storage module according to one embodiment.

[0015] Figure 8 This is a longitudinal sectional view schematically showing an example of the caulking step.

[0016] Fig. 9 The first variant involves Figure 5 Quite a picture.

[0017] Fig.10 The second variant involves Figure 5 Quite a picture. DETAILED DESCRIPTION

[0018] Hereinafter, the preferred embodiments of the technology disclosed herein will be described with reference to the accompanying drawings. Among them, matters necessary for the implementation of the present invention (for example, the general structure and manufacturing process of the power storage device that do not constitute the characteristics of the present invention) other than matters specifically mentioned in this specification can be grasped as design matters based on the prior art in the field by those skilled in the art. The technology disclosed herein can be implemented based on the contents disclosed in this specification and the technical common sense in the field.

[0019] <Electricity Storage Device 100>

[0020] Figure 1 It is a perspective view of the power storage device 100 . Figure 2 It is along Figure 1Schematic longitudinal cross-sectional view of line II-II of FIG. In the following description, the reference numerals L, R, U, and D in the drawings represent left, right, top, and bottom, and the reference numerals X, Y, and Z in the drawings represent the short side direction, the long side direction orthogonal to the short side direction, and the up and down direction of the power storage device 100, respectively. However, these are only for the convenience of explaining the directions and do not constitute any limitation on the setting method of the power storage device 100.

[0021] In this specification, the term "power storage device" refers to any device that can be repeatedly charged and discharged, and is a concept that includes storage batteries such as lithium ion secondary batteries and nickel metal hydride batteries, and capacitors such as lithium ion capacitors and electric double layer capacitors.

[0022] like Figure 2 As shown, the power storage device 100 includes an electrode body 10, a positive electrode current collecting component 13, a negative electrode current collecting component 14, a battery case 20, a positive terminal 30 and a negative terminal 40. The power storage device 100 is characterized by having the positive terminal 30 and / or the negative terminal 40 disclosed here, and the structure other than this can be the same as before. The power storage device 100 is preferably a secondary battery, and more preferably a non-aqueous electrolyte secondary battery. Here, the power storage device 100 is a lithium ion secondary battery. Although omitted from the figure, the power storage device 100 here also includes an electrolyte. The power storage device 100 is configured such that the electrode body 10 and the electrolyte not shown in the figure are accommodated in the battery case 20.

[0023] The electrode body 10 can be the same as in the past, without particular limitation. The electrode body 10 has a positive electrode and a negative electrode (not shown). The electrode body 10 is, for example, a flat wound electrode body in which a strip-shaped positive electrode and a strip-shaped negative electrode are stacked in an insulated state with a strip-shaped separator interposed therebetween and wound around a winding axis. However, in other embodiments, the electrode body 10 may also be a stacked electrode body in which a square (typically rectangular) positive electrode and a square (typically rectangular) negative electrode are stacked in an insulated state. One of the positive electrode and the negative electrode is an example of a "first electrode", and the other is an example of a "second electrode". Among them, the negative electrode is preferably the "first electrode".

[0024] The positive electrode has a positive electrode collector 11 and a positive electrode mixture layer (not shown) fixed on the positive electrode collector 11. The positive electrode collector 11 is composed of, for example, a conductive metal such as aluminum, an aluminum alloy, nickel, or stainless steel. The positive electrode mixture layer includes a positive electrode active material (for example, a lithium transition metal composite oxide). The negative electrode has a negative electrode collector 12 and a negative electrode mixture layer (not shown) fixed on the negative electrode collector 12. The negative electrode collector is composed of, for example, a conductive metal such as copper, a copper alloy, nickel, or stainless steel. The negative electrode mixture layer includes a negative electrode active material (for example, a carbon material such as graphite).

[0025] like Figure 2As shown by the oblique lines in the figure, a stacked portion in which the positive electrode mixture layer and the negative electrode mixture layer are stacked in an insulated state is formed in the central portion of the long side direction Y of the electrode body 10. On the other hand, at the left end portion of the long side direction Y of the electrode body 10, a portion of the positive electrode collector 11 (the positive electrode collector exposed portion) on which the positive electrode mixture layer is not formed protrudes from the stacked portion. A positive electrode collector component 13 is attached to the positive electrode collector exposed portion. The positive electrode collector component 13 can be made of the same metal material as the positive electrode collector 11, such as conductive metals such as aluminum, aluminum alloy, nickel, and stainless steel. The positive electrode collector component 13 electrically connects the positive electrode to the positive terminal 30 inside the battery case 20. The positive electrode collector component 13 electrically connects the positive electrode to the positive terminal 30 inside the battery case 20.

[0026] In addition, at the right end of the electrode body 10 in the long side direction Y, a part of the negative electrode collector 12 (the negative electrode collector exposed part) on which the negative electrode mixture layer is not formed protrudes from the stacked part. A negative electrode collector component 14 is attached to the negative electrode collector exposed part. The negative electrode collector component 14 can be made of the same metal type as the negative electrode collector 12, such as conductive metals such as copper, copper alloy, nickel, and stainless steel. The material (metal type) of the negative electrode collector component 14 can also be different from that of the positive electrode collector component 13. The negative electrode collector component 14 electrically connects the negative electrode to the negative terminal 40 inside the battery case 20.

[0027] The electrolyte can be the same as before, without particular limitation. The electrolyte is, for example, a non-aqueous liquid electrolyte (non-aqueous electrolyte) containing a non-aqueous solvent and an auxiliary salt. Non-aqueous solvents include, for example, carbonates such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. Auxiliary salts are, for example, fluorine-containing lithium salts such as LiPF6. However, the electrolyte can also be integrated with the electrode body 10 in a solid state (solid electrolyte).

[0028] The battery case 20 is a box that contains the electrode body 10. Here, the battery case 20 is formed into a flat rectangular parallelepiped (square) with a bottom. However, the shape of the battery case 20 is not limited to a square, and can also be any shape such as a cylinder. The material of the battery case 20 can be the same as the material that has been used, and there is no particular restriction. The battery case 20 is made of a light metal material with good thermal conductivity, such as aluminum, aluminum alloy, and stainless steel. Figure 2 The battery case 20 includes: a case body (external body) 22 having an opening 22h; and a cover (sealing plate) 24 that blocks the opening 22h. Preferably, the battery case 20 includes a case body 22 and a cover 24. The battery case 20 is integrated by joining (for example, welding) the cover 24 to the periphery of the opening 22h of the case body 22. The battery case 20 is hermetically sealed (sealed).

[0029] The shell body 22 has a bottom surface 22d. The cover body 24 is opposite to the bottom surface 22d of the shell body 22. The cover body 24 is installed on the shell body 22 in a manner to block the opening 22h of the shell body 22. Here, the cover body 24 is generally rectangular. In this specification, "generally rectangular" is a term other than a complete rectangular shape (rectangle), for example, including a shape in which the corners connecting the long sides and the short sides of the rectangular shape are arc-shaped, a shape with a cutout at the corner, etc.

[0030] like Figure 1 As shown, the positive terminal 30 and the negative terminal 40 protrude to the outside of the battery case 20. Here, the positive terminal 30 and the negative terminal 40 protrude from the same surface of the battery case 20 (specifically, the cover 24). However, the positive terminal 30 and the negative terminal 40 may protrude from different surfaces of the battery case 20. The positive terminal 30 and the negative terminal 40 are respectively arranged at the two end portions of the long side direction Y of the cover 24. The positive terminal 30 and / or the negative terminal 40 is an example of a "terminal for a storage device". Among them, it is preferred that the negative terminal 40 is a "terminal for a storage device".

[0031] like Figure 2 As shown, the positive terminal 30 is electrically connected to the positive electrode of the electrode body 10 via the positive electrode collector 13 inside the battery case 20. The negative terminal 40 is electrically connected to the negative electrode of the electrode body 10 via the negative electrode collector 14 inside the battery case 20. The positive terminal 30 and the negative terminal 40 are respectively installed in the battery case 20 (specifically, the cover 24). Preferably, the positive terminal 30 and the negative terminal 40 are fixed to the battery case 20 (specifically, the cover 24). The positive terminal 30 and the negative terminal 40 are respectively connected via the gasket 50 (refer to Figure 3 ) and an insulator 60 (refer to Figure 3 ) is insulated from the cover body 24.

[0032] Figure 3 4 is a partial enlarged cross-sectional view schematically showing the vicinity of the negative terminal 40. The terminal structure on the negative terminal 40 side is described in detail below as an example, and the terminal structure on the positive terminal 30 side can also be the same. In this case, the "negative electrode" part can be appropriately replaced with the "positive electrode" in the following description.

[0033] like Figure 3As shown, the cover body 24 is provided with a terminal lead hole 24h that penetrates in the up-down direction Z. Preferably, the battery case 20 is provided with a terminal lead hole 24h. Preferably, the terminal lead hole 24h is provided in the cover body 24. Although not shown in the figure, the terminal lead hole 24h is circular (e.g., a perfect circle) in a plan view. The terminal lead hole 24h has an inner diameter of a size that can be inserted through the shaft portion 42s of the negative terminal 40 described later before the caulking process. The terminal lead hole 24h is formed to be smaller than the flange portion 42f of the negative terminal 40 described later.

[0034] The negative electrode current collecting component 14 is attached to the negative electrode current collector exposed portion of the negative electrode current collector 12, and constitutes a conduction path that electrically connects the negative electrode to the negative terminal 40. The negative electrode current collecting component 14 has a flat plate-shaped portion 14f that extends horizontally along the surface of the inner side of the cover body 24. In the flat plate-shaped portion 14f, a hole portion 14h is provided at a position corresponding to the terminal lead-out hole 24h. The hole portion 14h has an inner diameter of a size that can be inserted through the shaft portion 42s of the negative terminal 40 described later before the caulking process. The negative electrode current collecting component 14 is fixed to the cover body 24 together with the negative terminal 40 in an insulated state by the caulking process with the aid of the insulating member 60. The negative electrode current collecting component 14 is an example of a "current collecting component".

[0035] The gasket 50 is an insulating member disposed between the upper surface (outer surface) of the cover 24 and the negative terminal 40. An insulating member (e.g., gasket 50) is preferably disposed between the battery case 20 (e.g., the cover 24) and the negative terminal 40. Here, the gasket 50 has the function of insulating the cover 24 from the negative terminal 40 and sealing the terminal lead-out hole 24h. The gasket 50 has electrical insulation and is composed of an elastically deformable resin material such as a fluorinated resin such as a perfluoroalkoxy fluorine resin (PFA), a polyphenylene sulfide resin (PPS), an aliphatic polyamide, and the like.

[0036] The gasket 50 has a barrel 51 and a base 52. The barrel 51 is a part that prevents direct contact between the cover 24 and the shaft 42s of the negative terminal 40. The barrel 51 is a hollow cylindrical shape. The barrel 51 has a hole 51h that penetrates in the up-down direction Z. The hole 51h is formed so that the shaft 42s of the negative terminal 40 before the caulking process can be inserted. The barrel 51 is inserted into the terminal lead-out hole 24h of the cover 24. The base 52 is a part that prevents direct contact between the cover 24 and the flange 42f of the negative terminal 40 described later. The base 52 is connected to the upper end of the barrel 51. The base 52 extends in the horizontal direction from the upper end of the barrel 51. The base 52 is formed in a circular ring shape, for example, in a manner that surrounds the terminal lead-out hole 24h of the cover 24. The base 52 extends along the upper surface of the cover 24. The base portion 52 is sandwiched between the lower surface 42 d of the flange portion 42 f of the negative electrode terminal 40 and the upper surface of the lid 24 , and is compressed in the up-down direction Z by caulking.

[0037] The insulating member 60 is an insulating member disposed between the lower surface (inner surface) of the cover 24 and the negative electrode current collecting member 14. It is preferred that an insulating member (e.g., insulating member 60) is disposed between the battery case 20 (e.g., cover 24) and the negative electrode current collecting member 14. The insulating member 60 has a flat plate-shaped portion extending horizontally along the inner surface of the cover 24. A hole portion 60h is formed in the flat plate-shaped portion at a position corresponding to the terminal lead-out hole 24h. The hole portion 60h has an inner diameter of a size that can be inserted through the shaft portion 42s of the negative terminal 40. The insulating member 60 has resistance and electrical insulation relative to the electrolyte used, and is composed of an elastically deformable resin material such as a fluorinated resin such as a perfluoroalkoxy fluorine resin (PFA), a polyphenylene sulfide resin (PPS), and the like. The flat plate-shaped portion of the insulating member 60 is sandwiched between the lower surface of the cover 24 and the upper surface of the negative electrode current collecting member 14, and is compressed in the vertical direction Z by caulking.

[0038] <Negative terminal 40>

[0039] like Figure 3 As shown, the negative terminal 40 is inserted through the terminal lead-out hole 24h and extends from the inside to the outside of the battery case 20. As described later, the negative terminal 40 is formed by integrating two conductive members, namely, the first conductive member 41 and the second conductive member 42, at least by an ultrasonic bonding portion 45. It is preferably formed by integrating by a fastening portion 43 and an ultrasonic bonding portion 45 as in the present embodiment.

[0040] like Figure 3 As shown, the negative terminal 40 is inserted into the terminal lead-out hole 24h of the cover body 24 and the hole portion 14h of the negative current collector 14, and the front end portion in the insertion direction (the cylindrical portion 42p described later) is crimped to the negative current collector 14. In detail, it is crimped to the peripheral portion of the hole portion 14h surrounding the negative current collector 14. A crimping portion 40c is formed at the lower end of the negative terminal 40. The negative terminal 40 is fixed to the cover body 24 by crimping processing and is electrically connected to the negative current collector 14. Here, the crimping portion 40c is cylindrical. However, the shape of the crimping portion 40c is not limited to a cylindrical shape, and can be any shape such as a columnar shape. Preferably, the crimping portion 40c is welded to the negative current collector 14.

[0041] Figure 4 1 is a schematic plan view of the negative electrode terminal 40 before being attached to the lid 24 (ie, before caulking). Figure 5 yes Figure 4 A schematic longitudinal cross-sectional view of the negative terminal 40. Figure 5As shown, the negative terminal 40 includes a first conductive component 41, a second conductive component 42, a fastening portion 43, and an ultrasonic bonding portion 45. The first conductive component 41 and the second conductive component 42 are electrically connected to each other by two connecting portions having different connection methods, namely, the fastening portion 43 and the ultrasonic bonding portion 45. As a result, it is easy to properly maintain the state in which the first conductive component 41 and the second conductive component 42 are in close contact. Therefore, the conduction reliability of the negative terminal 40 can be more appropriately improved. However, the fastening portion 43 is not necessary and can be omitted in other embodiments.

[0042] The first conductive component 41 is a component disposed outside the battery case 20. The first conductive component 41 is made of a first metal. The first conductive component 41 is made of, for example, a conductive metal such as aluminum, an aluminum alloy, nickel, or stainless steel. Preferably, the first conductive component 41 is made of aluminum or an aluminum alloy. Here, the first conductive component 41 is made of aluminum. Preferably, the first conductive component 41 is made of a metal having a smaller Vickers hardness than the second conductive component 42 (soft). The first conductive component 41 may be the same metal as the positive electrode current collecting component 13, or an alloy having the same metal element as the first component (the component having the highest mixing ratio by mass ratio. The same applies below).

[0043] like Figure 4 As shown in FIG. 1 , the first conductive component 41 is circular (eg, a perfect circle) when viewed from above. Figure 5 As shown, the outer diameter of the first conductive component 41 is larger than the flange portion 42f of the second conductive component 42 described later. The first conductive component 41 has an axis C. The first conductive component 41 has a lower surface (first surface) 41d and an upper surface (second surface) 41u. The lower surface 41d is the surface on the side opposite to the battery case 20 (specifically, the cover body 24). The lower surface 41d is the surface in contact with the second conductive component 42. The upper surface 41u is the surface on the opposite side of the lower surface 41d in the thickness direction of the first conductive component 41 (the direction perpendicular to the cover body 24). The upper surface 41u is the surface on the side away from the battery case 20 and the second conductive component 42. The upper surface 41u is provided for the external conductive component 80 described later (refer to Figure 6 Although not particularly limited, the thickness T of the first conductive member 41 (vertical distance from the upper surface 41u to the lower surface 41d) is preferably 0.5 to 5 mm, and more preferably 1 to 3 mm.

[0044] like Figure 5 As shown, the first conductive component 41 has a first recess 41r, a second recess 41c, a thin-walled portion 41t, and a rib 41s. However, in other embodiments, the first conductive component 41 may not have the thin-walled portion 41t and / or the second recess 41c. In addition, the first conductive component 41 does not have a through hole, but may have a through hole as described in the second modified example described later.

[0045] like Figure 5 As shown, the first recess 41r is provided on the lower surface (first face) 41d. The first recess 41r is recessed from the lower surface 41d. It is preferred that the first recess 41r is formed axially symmetrically with respect to the axis C of the first conductive component 41. Although not shown in the figure, the first recess 41r is circular in a plan view (including a roughly circular shape such as a perfect circle with a partial cutout). Here, the first recess 41r is formed in a tapered shape that decreases in diameter toward the lower surface 41d of the first conductive component 41 (in other words, the closer to the second conductive component 42). A portion of the flange portion 42f of the second conductive component 42 described later (specifically, the contraction portion 42n) is inserted into the first recess 41r. The first recess 41r is an example of a "recess on the first face".

[0046] The second recess 41c is provided on the upper surface (second surface) 41u. The second recess 41c is recessed from the upper surface 41u. It is preferred that the second recess 41c is formed axially symmetrically with respect to the axis C of the first conductive member 41. Figure 4 As shown in FIG. 1 , the second recess 41c is circular (e.g., a perfect circle) in a plan view. Figure 5 As shown, in a plan view, the outer diameter of the second recess 41c (the diameter in the case of a perfect circle, the shortest length passing through the center in the case of a non-perfect circle) is smaller than the outer diameter of the first recess 41r.

[0047] like Figure 4 As shown in FIG. 1 , the thin-walled portion 41t is circular (e.g., a perfect circle) when viewed from above. Figure 5 As shown, the thin-walled portion 41t is formed to be thinner than its peripheral portion. The thickness T2 of the thin-walled portion 41t is less than the thickness T of the first conductive component 41. Here, the thin-walled portion 41t is the area where the first recess 41r and the second recess 41c overlap when viewed from above. Preferably, the thin-walled portion 41t is provided by forming the second recess 41c on the surface (i.e., the upper surface 41u) opposite to the lower surface 41d on which the first recess 41r is formed as in the present embodiment. An ultrasonic bonding portion 45 is provided on the thin-walled portion 41t. Thus, less energy is required during bonding, and weldability can be improved. In addition, deformation and distortion of the first conductive component 41 can be suppressed to a small extent during ultrasonic bonding.

[0048] The first conductive member 41 has a first region A1 and a second region A2 as regions divided in the radial direction above the first recess 41r. The first region A1 is in the direction in which the cylindrical portion 42p of the second conductive member 42 described later extends ( Figure 5Here, the first region A1 is the region overlapping the cylindrical portion 42p in a plan view. In other words, it is the region directly above the cylindrical portion 42p. Here, the first region A1 is annular (e.g., circular). The first upper surface S1 on the opposite side of the first region A1 to the lower surface 41d is farther away from the lower surface 41d (or the second conductive component 42) than the second upper surface S2 of the second region A2. Figure 5 The thickness T1 of the first region A1 is, for example, smaller than the thickness T of the first conductive member 41 by an amount corresponding to the first recess 41r (ie, T1<T).

[0049] The second region A2 is located radially inward of the first region A1 and is a region where the ultrasonic bonding portion 45 is formed. Here, the second region A2 is the thin-walled portion 41t. The radial direction ( Figure 4 The width of the second region A2 in the longitudinal direction Y) is wider than the radial width of the first region A1. The second upper surface S2 (bottom surface of the second recess 41c) on the opposite side of the lower surface 41d of the second region A2 is located below the first upper surface S1 of the first region A1 by an amount corresponding to the second recess 41c. It is preferred that the second region A2 is not further toward the upper surface 41u side ( Figure 4 Thus, less energy is required during bonding, and the ultrasonic bonding portion 45 can be easily and stably formed in the second area A2. In addition, during ultrasonic bonding, the deformation and deformation of the first conductive member 41 can be suppressed to be small.

[0050] Here, the thickness T2 of the second area A2 is smaller than the thickness T1 of the first area A1 by an amount corresponding to the second recess 41c (i.e., T2<T1<T). The thickness T1 of the first area A1 and the thickness T2 of the second area A2 preferably satisfy T1 / T2≤0.5, and more preferably satisfy T1 / T2<0.5. As a result, the ultrasonic bonding portion 45 can be formed more stably in the second area A2. In addition, when the thickness T2 of the second area A2 is thin, since the second area A2 is easily deformed and the ultrasonic bonding portion 45 is easily damaged, the application of the technology disclosed here has a particularly high effect. However, as also described in the second modified example described later, the first upper surface S1 of the first area A1 and the second upper surface S2 of the second area A2 can be the same or approximately the same height.

[0051] The rib 41s protrudes from the upper surface (second surface) 41u. The rib 41s is arranged on the outer peripheral side of the ultrasonic bonding portion 45. The rib 41s is arranged on the inner peripheral side of the fastening portion 43. The rib 41s is arranged between the first area A1 and the second area A2 in the radial direction. By providing the rib 41s between the first area A1 and the second area A2, it is possible to suppress deformation of the second area A2 and damage to the ultrasonic bonding portion 45 in the manufacturing process described later (for example, caulking processing of the terminal to the collector, etc.). Therefore, the reliability of the connection portion between the first conductive component 41 and the second conductive component 42 can be improved. The rib 41s can also be arranged at a position away from the outer peripheral edge of the second recess 41c.

[0052] The rib 41s is preferably formed axially symmetrically with respect to the axis C of the first conductive component 41. Here, the rib 41s is annular (e.g., circular). The rib 41s is preferably arranged in an annular shape so as to surround the second area A2. The rib 41s may be partially arranged in the first area A1. The ratio of the formation area of ​​the rib 41s to the area of ​​the first area A1 is preferably less than 0.5, and more preferably less than 0.3. Although the details will be described later, when a plurality of storage devices 100 are electrically connected to each other to form a storage module 200 (see Figure 7 ) In the case of the rib 41s, an external conductive member 80 may be attached (see Figure 6 For example, the external conductive member 80 may be metal-bonded (eg, welded) to the rib 41s.

[0053] The second conductive component 42 is a component that is inserted through the terminal lead-out hole 24h and extends from the inside to the outside of the battery case 20. The second conductive component 42 is made of a second metal different from the first metal. The second conductive component 42 is made of, for example, a conductive metal such as copper, a copper alloy, nickel, or stainless steel. Preferably, the second conductive component 42 is made of copper or a copper alloy. Here, the second conductive component 42 is made of copper. Preferably, the second conductive component 42 is made of a metal having a Vickers hardness greater than that of the first conductive component 41 (hardness). The second conductive component 42 may be the same metal as the negative electrode current collector 14, or an alloy having the same metal element as the first component. The second conductive component 42 may have a metal coating portion coated with a metal such as Ni on a portion or all of its surface.

[0054] like Figure 5As shown, the second conductive component 42 has an axis C. The axis C of the second conductive component 42 coincides with the axis C of the first conductive component 41. Here, the second conductive component 42 has: a flange portion 42f electrically connected to the first conductive component 41; a shaft portion 42s connected to the lower end of the flange portion 42f; and a cylindrical portion 42p located at the end (lower end) of the shaft portion 42s opposite to the side where the flange portion 42f is located. Preferably, the second conductive component 42 has a flange portion 42f and a shaft portion 42s connected to one surface of the flange portion 42f. The second conductive component 42 has a portion arranged in the first recess 41r of the first conductive component 41. Preferably, at least a portion of the flange portion 42f of the second conductive component 42 is arranged in the first recess 41r of the first conductive component 41.

[0055] The flange portion 42f has a larger outer shape than the shaft portion 42s. The flange portion 42f is a portion that protrudes from the terminal lead-out hole 24h of the cover body 24 to the outside of the battery case 20. Figure 3 As shown, the outer shape of the flange portion 42f is larger than the outer shape of the terminal lead-out hole 24h of the cover body 24. Here, the outer shape of the flange portion 42f is roughly cylindrical. Preferably, the flange portion 42f is circular (for example, a perfect circle) when viewed from above. The axis of the flange portion 42f coincides with the axis C of the second conductive component 42. In the present embodiment, the flange portion 42f has a lower surface 42d, a side surface (outer peripheral surface) 42o extending upward from the lower surface 42d, and a contraction portion 42n in which a portion of the side surface 42o is contracted.

[0056] The contraction portion 42n is continuously or intermittently provided on a portion of the side surface 42o of the flange portion 42f. The contraction portion 42n is preferably mechanically fastened to the first conductive component 41 (for example, the inner side surface of the first recess 41r). Although not shown in the figure, the contraction portion 42n is annular (for example, circular ring-shaped) when viewed from above. The contraction portion 42n is formed to be axially symmetrical with respect to the axis C of the flange portion 42f. The contraction portion 42n is formed into an inverted cone shape that expands toward the upper surface 41u (in other words, the farther away from the shaft portion 42s, the larger the diameter). The contraction portion 42n is inserted into the first recess 41r of the first conductive component 41. Here, the contraction portion 42n is embedded in the first recess 41r of the first conductive component 41 and is interlocked with the first recess 41r. The contraction portion 42n is an example of a "portion arranged in the recess".

[0057] like Figure 5 As shown in FIG. 4 , the shaft portion 42s extends downward from the lower end portion of the flange portion 42f. Figure 3As shown, when the negative terminal 40 is mounted on the cover 24, the shaft portion 42s is preferably inserted into the terminal lead-out hole 24h of the cover 24. Although not shown in the figure, the outer shape of the shaft portion 42s is cylindrical. The axis of the shaft portion 42s coincides with the axis C of the second conductive member 42. Before the caulking process, the lower end of the shaft portion 42s, that is, the end on the side opposite to the side where the flange portion 42f is located, is hollow. The lower end of the shaft portion 42s constitutes a cylindrical portion 42p.

[0058] Here, the cylindrical portion 42p is a hollow cylindrical shape. The cylindrical portion 42p extends along the up-down direction Z. The cylindrical portion 42p is arranged outside the first recess 41r. The cylindrical portion 42p is a portion that is expanded by caulking to form a caulking portion 40c when the negative terminal 40 is mounted on the cover 24. Preferably, the cylindrical portion 42p is electrically connected to the negative electrode current collecting component 14 inside the battery case 20 by caulking.

[0059] The fastening portion 43 is a connecting portion that mechanically fastens the first conductive component 41 and the second conductive component 42. By having the fastening portion 43, the connection state of the first conductive component 41 and the second conductive component 42 is more easily stabilized. The fastening portion 43 is arranged on the outer peripheral side than the ultrasonic bonding portion 45. The fastening portion 43 is arranged on the outer peripheral side than the cylindrical portion 42p. The fastening portion 43 is arranged on the outer peripheral side than the rib 41s. Here, the fastening portion 43 is continuously formed. Here, the fastening portion 43 is annular (e.g., circular ring-shaped) when viewed from above. Thereby, the strength of the fastening portion 43 can be improved and the conduction reliability of the negative terminal 40 can be improved.

[0060] Here, the fastening portion 43 is configured such that a portion of the inner wall of the first recess 41r of the first conductive component 41 enters into the contraction portion 42n of the second conductive component 42. Thus, the inner wall of the first recess 41r of the first conductive component 41 is fixed (for example, pressed and fixed) by the contraction portion 42n of the second conductive component 42. Preferably, the fastening portion 43 is configured by fastening the inner wall of the first recess 41r of the first conductive component 41 to the side surface 42o of the flange portion 42f of the second conductive component 42. Thus, the strength of the fastening portion 43 can be improved.

[0061] The method for forming the fastening portion 43 is not particularly limited as long as it is a mechanical joint based on mechanical energy, and may be, for example, press-fitting, heat press fitting, caulking, riveting, folding, bolting, etc. In some preferred embodiments, the fastening portion 43 is preferably a fitting portion where the first recessed portion 41r of the first conductive component 41 and the contracted portion 42n of the second conductive component 42 are fitted. The fastening portion 43 may be, for example, a press-fit fitting portion where the contracted portion 42n of the second conductive component 42 is fitted (self-clinched) into the first recessed portion 41r of the first conductive component 41 by press-fitting. Thus, the first conductive component 41 and the second conductive component 42 can be appropriately fixed.

[0062] The ultrasonic bonding portion 45 is a metal bonding portion formed by ultrasonic bonding of the first conductive member 41 and the second conductive member 42. The ultrasonic bonding portion 45 is provided in the second area A2. The ultrasonic bonding portion 45 is provided on the inner peripheral side of the rib 41s. The ultrasonic bonding portion 45 is provided on the inner peripheral side of the cylindrical portion 42p. Here, the ultrasonic bonding portion 45 is provided in the thin-walled portion 41t. Here, the ultrasonic bonding portion 45 is provided at a position separated from the fastening portion 43. The ultrasonic bonding portion 45 is provided on the inner peripheral side (center side) of the fastening portion 43. The ultrasonic bonding portion 45 can be a bonding portion with a relatively lower strength (brittle) than the fastening portion 43. By arranging such an ultrasonic bonding portion 45 on the inner peripheral side of the fastening portion 43, the ultrasonic bonding portion 45 can be stably maintained, and the conduction reliability of the negative terminal 40 can be improved for a long time. Among them, the ultrasonic bonding portion 45 can be clearly distinguished from, for example, laser welding, based on the crimping mark of the welding head used in the ultrasonic bonding process described later.

[0063] The ultrasonic bonding portion 45 is formed continuously or intermittently in a plan view. Preferably, the ultrasonic bonding portion 45 is formed to be axisymmetric with respect to the axis C of the first conductive member 41 and the second conductive member 42 (for example, the flange portion 42f). Figure 4 As shown, the ultrasonic bonding portion 45 is circular (e.g., a perfect circle) in a plan view. Thus, the strength of the ultrasonic bonding portion 45 can be improved, and the conduction reliability of the negative terminal 40 can be improved. In addition, the area of ​​the ultrasonic bonding portion 45 can be used to reduce the conduction resistance and the resistance. Moreover, the resistance heating can be suppressed to a low level, for example, the thermal influence on the resin parts such as the gasket 50 can be reduced.

[0064] In some preferred embodiments, the negative terminal 40 further includes an external conductive member 80 (see Figure 6 ). Figure 6 4 is a longitudinal cross-sectional view schematically showing the connection between the negative electrode terminal 40 and the external conductive member 80. Figure 6 As shown, here, the external conductive component 80 is attached to the rib 41s of the first conductive component 41. In detail, the external conductive component 80 is metal-bonded to the rib 41s (for example, welded). Preferably, the external conductive component 80 is made of the same metal as the first conductive component 41, or an alloy having the same metal element as the first component. Preferably, the external conductive component 80 is made of the first metal constituting the first conductive component 41. Preferably, the external conductive component 80 is made of aluminum or an aluminum alloy. Here, the external conductive component 80 is made of aluminum. Preferably, the external conductive component 80 is plate-shaped (in detail, flat plate-shaped).

[0065] according to Figure 7It can be seen that the external conductive component 80 is a generally rectangular shape having short sides and long sides in a plan view. The external conductive component 80 is configured such that the long side of the rectangle is along the long side direction Y of the cover 24. It is preferred that the external conductive component 80 extends along the long side direction Y of the cover 24 as in the present embodiment.

[0066] like Figure 6 As shown, the external conductive component 80 is a region divided into two parts in the longitudinal direction Y, and has a connecting portion 80a electrically connected to the rib 41s and a side ( Figure 6 An extension portion 80b extending to the left of the device.

[0067] In the connecting portion 80a, a welding joint 82 is provided at the outer periphery of the rib 41s. The welding joint 82 is formed continuously or intermittently in a plan view. Here, the welding joint 82 is provided continuously. The welding joint 82 is circular (e.g., a perfect circle). Preferably, the welding joint 82 is a laser welding portion. According to the research of the present inventors, if the metal joint between the external conductive component 80 and the first conductive component 41 reaches the second conductive component 42, there is a concern that the metal joint becomes brittle. By metal-bonding the external conductive component 80 to the rib 41s, it is possible to suppress the metal joint between the external conductive component 80 and the first conductive component 41 from reaching the second conductive component 42, and to suppress the reduction in the reliability of the joint. Therefore, the conduction reliability of the battery module 200 can be improved. However, the external conductive component 80 does not necessarily need to be attached to the rib 41s, and in other embodiments, it can also be attached outside the rib 41s.

[0068] The extension portion 80b is used to electrically connect a plurality of power storage devices 100 to form a power storage module 200 (see Figure 7 ) in the case of supplying bus bar 90 (refer to Figure 7 ) is provided. By having the extension portion 80b, the grounding area with the bus bar 90 can be sufficiently ensured, and the conduction reliability of the storage module 200 can be improved. However, in other embodiments, the bus bar 90 can also be directly connected to the first conductive component 41 (for example, the upper surface 41u or the rib 41s) without passing through the external conductive component 80 (or the extension portion 80b).

[0069] <Method for Manufacturing Negative Electrode Terminal 40>

[0070] The negative terminal 40 as described above can be suitably manufactured, for example, by a manufacturing method that sequentially includes the following steps: a fastening step of preparing the first conductive component 41 and the second conductive component 42 and mechanically fastening the first conductive component 41 and the second conductive component 42; and an ultrasonic bonding step of ultrasonically bonding the first conductive component 41 and the second conductive component 42. By performing the bonding step after the fastening step, it is possible to prevent the ultrasonic bonding portion 45 from being damaged in the fastening step, and to form the ultrasonic bonding portion 45 with a stable shape with high precision. However, the order of the fastening step and the bonding step may be reversed or performed approximately simultaneously. In addition, the manufacturing method disclosed herein may also include other steps at any stage.

[0071] In the fastening process, the first conductive component 41 and the flange portion 42f of the second conductive component 42 are mechanically fastened to form the fastening portion 43. For example, the fastening portion 43 can be formed by disposing the contraction portion 42n of the second conductive component 42 in the first recess 41r of the first conductive component 41 and deforming the first recess 41r of the first conductive component 41 along the outer shape of the contraction portion 42n of the second conductive component 42 to fix the inner wall of the first recess 41r with the second conductive component 42. Thus, the strength of the fastening portion 43 can be improved. In some preferred embodiments, the fastening portion 43 is formed by fitting the first recess 41r of the first conductive component 41 with the contraction portion 42n of the second conductive component 42 (self-caulking). For example, it can be formed by horizontally pressing the contraction portion 42n of the second conductive component 42 into the first recess 41r of the first conductive component 41. Thus, the workability of the fastening process can be improved.

[0072] In the ultrasonic bonding process, in a state where a part of the second conductive component 42 (for example, the flange portion 42f) is arranged in the first recess 41r of the first conductive component 41, the second conductive component 42 is ultrasonically bonded to form an ultrasonic bonded portion 45 in the second region A2 of the first conductive component 41. Here, the ultrasonic bonded portion 45 is formed by ultrasonically bonding the second conductive component 42 to the thin-walled portion 41t. In ultrasonic bonding, for example, the horn is pressed to the second region A2 (specifically the thin-walled portion 41t) of the first conductive component 41, and ultrasonic vibration is applied while applying a press load. Among them, the method and conditions of ultrasonic bonding can be the same as before. In ultrasonic bonding, for example, compared with laser welding, it is difficult to generate brittle intermetallic compounds at the bonding interface between the first conductive component 41 and the second conductive component 42. Therefore, a high-strength metal bonded portion can be stably formed. In addition, in the present embodiment, since the second region A2 is composed of the thin-walled portion 41t, even if the first conductive component 41 is deformed in this process, the flow of the wall can be appropriately dissipated to the rib 41s. Therefore, even if the first conductive member 41 does not have a through hole, for example, it is possible to suppress the occurrence of unintended strain or deformation in the first conductive member 41 .

[0073] <Method of Manufacturing Power Storage Device 100>

[0074] The power storage device 100 has a feature by using the positive electrode terminal 30 and / or the negative electrode terminal 40 as described above, and the manufacturing process other than this can be the same as in the past. The power storage device 100 can be manufactured by, for example, preparing the electrode body 10, electrolyte, case body 22, cover body 24, positive electrode terminal 30 and negative electrode terminal 40 as described above and using a manufacturing method including a terminal mounting process and a case joining process in sequence.

[0075] In the terminal mounting step, the positive electrode terminal 30, the positive electrode current collecting component 13, the negative electrode terminal 40, and the negative electrode current collecting component 14 are mounted on the cover 24 to form an integrated whole. Figure 3 As shown, the negative terminal 40 and the negative electrode current collector 14 are fixed to the cover 24 by riveting. In some preferred embodiments, this process includes an insertion process and a riveting process in sequence. In addition, other processes may be included at any stage. For example, the external conductive component installation process described later may be included after the riveting process.

[0076] In the insertion step, a portion of the second conductive member 42 of the negative terminal 40 is inserted into the hole 14h of the negative current collecting member 14. Specifically, the shaft portion 42s before the caulking process is passed through the cylindrical portion 51 of the gasket 50, the terminal lead hole 24h of the cover 24, the hole 60h of the insulating member 60, and the hole 14h of the negative current collecting member 14 in order from the top of the cover 24. As a result, the cylindrical portion 42p of the negative terminal 40 protrudes downward from the hole 14h of the negative current collecting member 14.

[0077] In the caulking process, the second conductive member 42 of the negative terminal 40 is caulked onto the negative current collector 14. Specifically, the cylindrical portion 42p protruding from the hole 14h of the negative current collector 14 is caulked onto the negative current collector 14 in a manner that applies a compressive force in the up-down direction Z. Here, the caulking process is performed by sandwiching a gasket 50 between the negative terminal 40 and the cover 24, and further sandwiching an insulating member 60 between the cover 24 and the negative current collector 14. Thus, at the front end portion ( Figure 3 The lower end portion of the caulking portion 40c is formed.

[0078] Figure 8 is a longitudinal sectional view schematically showing an example of this process. Figure 8 In the figure, the cover 24, the gasket 50, the insulating member 60 and the negative electrode current collecting member 14 are omitted. In several preferred embodiments, first, as Figure 8 As shown, a caulking device including a punch (stamping fixture) 91 and a die (supporting fixture) 92 is prepared. Here, the die 92 is a hollow cylindrical shape, and has a hollow portion in the center portion whose inner diameter is larger than the outer diameter of the rib 41s of the first conductive component 41. Although not particularly limited, in the present embodiment, the inner diameter of the die 92 is Φ=8.2 mm, and the outer diameter is Φ=15 mm or more. Next, the negative terminal 40 is arranged on the top surface of the die 92 in a state in which it is inverted upside down. As a result, the upper surface 41u of the first conductive component 41, more specifically, the portion closer to the outer peripheral side than the rib 41s, is opposed to the die 92. The portion of the upper surface 41u closer to the outer peripheral side than the rib 41s abuts against the die 92.

[0079] In the present embodiment, the first conductive component 41 has a second recess 41c on the upper surface 41u. The first region A1 of the first conductive component 41 protrudes toward the upper surface 41u side more than the second region A2. In other words, the first upper surface S1 (the surface opposite to the surface on the side where the first recess 41r is formed) of the first region A1 of the first conductive component 41 is more inclined toward the direction away from the lower surface 41d (in the direction of the first region A2) than the second upper surface S2 (the surface opposite to the surface on the side where the first recess 41r is formed) of the second region A2. Figure 8The first upper surface S1 of the first region A1 is at least partially (more than half of the first upper surface S1 in this case) in contact with the die 92. On the other hand, the second upper surface S2 of the second region A2 in which the ultrasonic bonding portion 45 is formed floats from the die 92. The second conductive component 42 does not in contact with the die 92. Thus, damage to the ultrasonic bonding portion 45 can be more effectively suppressed.

[0080] Next, the tip of the punch 91 is inserted into the cylindrical portion 42p (hollow portion) of the second conductive member 42 while at least a portion of the first upper surface S1 of the first region A1, which is closer to the outer periphery than the rib 41s, is in contact with the die 92. Figure 8 As shown by the arrow in the figure, by applying a compressive force in the direction in which the cylindrical part 42p extends (the direction in which the axis C extends, here the vertical direction Z), the front end of the punch 91 is used to expand the cylindrical part 42p and deform it. As a result, the cylindrical part 42p is plastically deformed in a manner that the outer edge portion is embraced. As a result, the caulking portion 40c is formed on the negative electrode current collector component 14, and each component is fixed by caulking.

[0081] In the present embodiment, a rib 41s is provided between the first area A1 and the second area A2 in the first conductive component 41. Thus, in this process, deformation of the second area A2 and damage to the ultrasonic bonding portion 45 provided in the second area A2 can be effectively suppressed. Therefore, a terminal with high reliability is formed at the connection portion between the first conductive component 41 and the second conductive component 42. In addition, in the present embodiment, the area of ​​the ultrasonic bonding portion 45 is increased by not having a through hole in the first conductive component 41, so that the conduction resistance and the resistance can be reduced. In addition, the resistance heating can be suppressed to a low level, for example, the thermal influence on the resin components such as the gasket 50 can be reduced.

[0082] In addition, in the present embodiment, the first region A1 protrudes toward the upper surface 41u side more than the second region A2. Thus, the die 92 can be used to bear directly below the cylindrical portion 42p, and the cylindrical portion 42p can be easily caulked. Furthermore, since the second region A2 is recessed toward the lower surface 41d side more than the first region A1 (located above), it is difficult to apply a compressive force of caulking to the region where the ultrasonic bonding portion 45 is formed. Therefore, the load on the second region A2 or the ultrasonic bonding portion 45 provided in the second region A2 can be reduced at a higher level, and damage to the ultrasonic bonding portion 45 can be more effectively suppressed.

[0083] By the above-mentioned caulking process, the base 52 of the gasket 50 and the flat plate-shaped part of the insulating member 60 are compressed, and the gasket 50, the cover 24, the insulating member 60 and the negative electrode collector member 14 are fixed to the cover 24 as a whole, and the terminal lead-out hole 24h is sealed. The negative electrode collector member 14 is welded to the negative electrode collector exposed portion of the negative electrode collector 12, so that the negative electrode of the electrode body 10 is electrically connected to the negative terminal 40. Among them, the installation method of the positive terminal 30 and the positive electrode collector member 13 can also be the same as the above-mentioned negative terminal 40 and the negative electrode collector member 14. The negative electrode collector member 14 is welded to the negative electrode collector exposed portion of the negative electrode collector 12, so that the negative electrode of the electrode body 10 is electrically connected to the negative terminal 40. As a result, the cover 24, the positive terminal 30, the negative terminal 40 and the electrode body 10 are integrated.

[0084] In some embodiments, an external conductive component installation step is included in which an external conductive component 80 is attached to the negative terminal 40 (e.g., welded) after the caulking step. Preferably, the welding of the external conductive component 80 is performed after the caulking step. In this step, the external conductive component 80 is welded (e.g., laser welded) to the annular rib 41s. Thus, for example, a welded portion 82 is formed at the peripheral edge of the rib 41s of the first conductive component 41, and the external conductive component 80 is installed on the negative terminal 40.

[0085] In the shell joining process, the electrode body 10 integrated with the cover body 24 is accommodated in the internal space of the shell body 22, and the cover body 24 is welded and joined at the periphery of the opening 22h of the shell body 22. Welding can be performed by a conventionally known method (such as laser welding). Thus, the opening 22h of the shell body 22 is sealed, and the shell body 22 and the cover body 24 are integrated. Then, the power storage device 100 is sealed by injecting a non-aqueous electrolyte from an injection port not shown in the figure and sealing the injection port. The power storage device 100 can be manufactured as described above.

[0086] <Application of the power storage device 100 >

[0087] The power storage device 100 can be used in various applications and can be suitably used as a power source (driving power source) for a motor mounted on various vehicles such as passenger cars and trucks. The type of vehicle is not particularly limited, and examples thereof include plug-in hybrid electric vehicles (PHEV), hybrid electric vehicles (HEV), and battery electric vehicles (BEV). The power storage device 100 can also be used as a power source (driving power source) for a motor mounted on various vehicles such as passenger cars and trucks. Figure 7 ) A power storage module 200 in which a plurality of power storage devices 100 are electrically connected to each other is appropriately used.

[0088] Figure 7 2 is a perspective view schematically showing a power storage module 200 according to an embodiment. Figure 7 As shown, the power storage module 200 includes a plurality of power storage devices 100 and a bus bar 90 that electrically connects the first power storage device 100 and the second power storage device 100 to each other. The bus bar 90 is made of, for example, a conductive metal such as aluminum, an aluminum alloy, nickel, or stainless steel. The bus bar 90 is in the form of a flat plate, and is mounted on the positive terminal 30 of the first power storage device 100 and the negative terminal 40 of the second power storage device 100 via an extension portion 80b of an external conductive member 80. The bus bar 90 is preferably welded (for example, laser welded) to the external conductive member 80.

[0089] Several embodiments of the present invention have been described above, but the above embodiment is only an example. In addition, the present invention can be implemented in various ways. The present invention can be implemented based on the contents disclosed in this specification and the technical common sense in the field. The technology described in the scope of protection requested by this application includes technologies obtained by various deformations and changes to the above-mentioned exemplified embodiments. For example, part of the above-mentioned embodiment can be replaced with other deformation forms, and other deformation forms can be added to the above-mentioned embodiment. In addition, as long as the technical feature is not described as being necessary, it can also be appropriately deleted.

[0090] (1) For example, in the above-mentioned embodiment Figure 4 In the embodiment, the first conductive component 41 is circular in a plan view. However, it is not limited to this. For example, as described in Japanese Patent Application Publication No. 2022-049729, the first conductive component 41 may be rectangular with long sides and short sides, for example, with an extension portion. In this case, when constructing the battery module 200, the bus bar 90 may be directly connected to the extension portion of the first conductive component 41 without passing through the external conductive component 80.

[0091] (2) For example, in the above-mentioned embodiment Figure 5 In the embodiment, the constricted portion 42n is provided at a part of the side surface 42o of the second conductive member 42. However, the present invention is not limited thereto. The constricted portion 42n may be provided at a part other than the side surface 42o, for example.

[0092] Fig. 9 The first variant involves Figure 5 Equivalent figure. Fig. 9 As shown, the negative electrode terminal 140 according to this modification includes a first conductive member 141, a second conductive member 142, a fastening portion 143, and an ultrasonic bonding portion 45. The first conductive member 141 does not have a thin-walled portion 41t and a second recessed portion 41c, and is formed as a whole. Figure 5The second conductive member 142 may be similar to the first conductive member 41 except that the second conductive member 142 has a constricted portion 142n on the upper surface 142u of the flange portion 142f and the flange portion 142f is formed to be smaller than the flange portion 142f. Figure 5 Except for the thickness, it can be the same as the second conductive member 42. The fastening portion 143 is a fitting portion that fits the first recess 41r of the first conductive member 141 and the constricted portion 142n provided on the upper surface 142u of the second conductive member 142.

[0093] In this modification, the outer diameter R1 of the first conductive member 141 is substantially the same as the outer diameter R2 of the flange portion 142f of the second conductive member 142. According to this modification, since the proportion of the second conductive member 142 is increased in the region overlapping with the cylindrical portion 42p (region compressed in the caulking process), particularly when the Vickers hardness of the second conductive member 142 is greater than that of the first conductive member 141, the load on the second region A2 or the ultrasonic bonding portion 45 provided in the second region A2 can be reduced at a higher level, and damage to the ultrasonic bonding portion 45 can be more effectively suppressed.

[0094] (3) For example, in the above-mentioned embodiment Figure 5 In the embodiment, the first conductive component 41 does not have a through hole, and the ultrasonic bonding portion 45 is arranged in a circular shape when viewed from above. In addition, the first upper surface S1 of the first area A1 protrudes in the thickness direction more than the second upper surface S2 of the second area A2. However, it is not limited to this. The first conductive component 41 may also have a through hole, and the ultrasonic bonding portion 45 may be annular when viewed from above. The first upper surface S1 of the first area A1 and the second upper surface S2 of the second area A2 may be the same or substantially the same height.

[0095] Fig.10 The second variant involves Figure 5 Equivalent figure. Fig.10 As shown, the negative electrode terminal 240 according to this modification includes a first conductive member 241, a second conductive member 242, a fastening portion 43, and an ultrasonic bonding portion 245. The first conductive member 241 has a through hole 241h and is formed as a whole. Figure 5 The second conductive member 242 may be similar to the first conductive member 41 except that the flange portion 242f is formed to be thinner than the first conductive member 41. Figure 5 Except for the thickness, it can be the same as the second conductive member 42 .

[0096] The through hole 241h penetrates the first conductive member 241 in the up-down direction Z. The through hole 241h is provided on the inner peripheral side (center side) of the fastening portion 43 and the ultrasonic bonding portion 245. The through hole 241h is provided in the central portion of the second area A2. Here, the through hole 241h is circular (e.g., a perfect circle) in a plan view. Although not particularly limited, the outer diameter of the through hole 241h (the diameter in the case of a perfect circle, the shortest length passing through the center in the case of a non-perfect circle) is preferably, for example, 5 to 7 mm.

[0097] Here, the ultrasonic bonding part 245 is continuously formed along the circumference of the through hole 241h. The ultrasonic bonding part 245 is arranged around the through hole 241h. Here, the ultrasonic bonding part 245 is arranged at a position away from the through hole 241h. The ultrasonic bonding part 245 is annular (e.g., circular ring-shaped) when viewed from above. However, the ultrasonic bonding part 245 can also be composed of multiple parts, and the multiple parts are respectively arranged at separated positions.

[0098] In this modification, the first upper surface S1 of the first region A1 and the second upper surface S2 of the second region A2 are the same or substantially the same height. The thickness T1 of the first region A1 and the thickness T2 of the second region A2 are substantially the same thickness (T1≈T2). The thickness T1 of the first region A1 and the thickness T2 of the second region A2 preferably satisfy the following relationship: 0.8≤T1 / T2≤1.2, and more preferably satisfy the following relationship: 0.8<T1 / T2<1.2. Since the rib 41s is provided between the first region A1 and the second region A2, even if T1 and T2 are substantially the same thickness, during the caulking process, the load on the second region A2 or the ultrasonic bonding portion 245 provided in the second region A2 can be reduced at a higher level, and damage to the ultrasonic bonding portion 245 can be effectively suppressed. In particular, when the thickness T1 of the first region A1 is thin (for example, when T1 is 1.5 mm or less, and further 0.8 mm or less), this modification is particularly preferred. The thickness T1 of the first region A1 is preferably 0.1 mm or more. The thickness T2 of the second region A2 is preferably, for example, 2.0 mm or less, more preferably 0.6 mm or less. The thickness T2 of the second region A2 is preferably 0.1 mm or more.

[0099] In this modification, it is preferred that the thickness (maximum thickness) T3 of the flange portion 242f and the thickness T1 of the first region A1 satisfy 3≤T3 / T1. By making the thickness of the flange portion 242f larger than the thickness T1 of the first region A1, it is possible to suppress undesirable deformation during the caulking process of the cylindrical portion 42p described later. In addition, it is possible to suppress the load applied to the ultrasonic bonding portion 245.

[0100] (4) For example, in the above-mentioned embodiment, the negative electrode terminal 40 is fixed to the negative electrode current collecting member 14 by deforming the cylindrical portion 42p of the negative electrode terminal 40 to perform caulking, and the negative electrode terminal 40 is electrically connected to the negative electrode current collecting member 14. However, the present invention is not limited thereto. The method of electrically connecting the negative electrode current collecting member 14 to the negative electrode terminal 40 may be, for example, mechanical fixing other than caulking, or metal joining represented by welding, or a combination thereof.

[0101] As described above, specific aspects of the technology disclosed herein include the aspects described in the following items.

[0102] Item 1: A terminal for a power storage device, comprising: a first conductive component, formed of a first metal, and having a recess on a first surface; a second conductive component, formed of a second metal different from the first metal, and having a portion arranged in the recess; and an ultrasonic bonding portion, for ultrasonically bonding the first conductive component to the second conductive component, wherein the first conductive component has a rib, the rib being arranged closer to the outer periphery than the ultrasonic bonding portion and protruding from a second surface of the first conductive component on the opposite side of the first surface.

[0103] Item 2: A terminal according to Item 1, wherein the second conductive component has a hollow cylindrical portion, and when a region of the first conductive component that overlaps with the cylindrical portion in a direction in which the cylindrical portion extends is taken as a first region, and a region that is located on the inner side of the first region and where the ultrasonic joining portion is formed is taken as a second region, the rib is arranged between the first region and the second region.

[0104] Item 3: The terminal according to Item 2, wherein the second region does not protrude toward the second surface side as much as the first region does.

[0105] Item 4: The terminal according to Item 2 or Item 3, wherein the thickness T1 of the first region and the thickness T2 of the second region satisfy the following relationship: 0.8≤T1 / T2≤1.2.

[0106] Item 5: A terminal according to any one of items 2 to 4, wherein the second conductive component is made of copper or a copper alloy and has a flange portion, at least a portion of the flange portion is arranged in the recessed portion of the first conductive component, and a thickness T3 of the flange portion and a thickness T1 of the first region satisfy the following relationship: 3≤T3 / T1.

[0107] Item 6: The terminal according to Item 2 or Item 3, wherein a thickness T1 of the first region and a thickness T2 of the second region satisfy the following relationship: T1 / T2≤0.5.

[0108] Item 7: The terminal according to any one of Items 1 to 6, further comprising a fastening portion that mechanically fastens the first conductive member and the second conductive member at an outer peripheral side of the ultrasonic bonding portion.

[0109] Item 8: The terminal according to any one of Items 1 to 7, further comprising an external conductive member joined to the rib of the first conductive member by welding.

[0110] Item 9: A method for manufacturing an electrical storage device, the electrical storage device comprising: an electrode body having a first electrode and a second electrode having a polarity different from that of the first electrode; a battery case housing the electrode body; a terminal electrically connected to the first electrode and mounted on the battery case; and a current collecting component having a hole portion and electrically connecting the first electrode to the terminal inside the battery case, the terminal comprising: a first conductive component made of a first metal and having a recess on a first surface; a second conductive component made of a second metal different from the first metal and having a portion disposed in the recess; and ultrasonic bonding The first conductive component is ultrasonically bonded to the second conductive component, the first conductive component having a rib, the rib being arranged closer to the outer periphery than the ultrasonic bonding portion and protruding from the second surface of the first conductive component opposite to the first surface, wherein the manufacturing method of the power storage device comprises: an insertion step of inserting a portion of the second conductive component of the terminal into the hole portion of the current collecting component; and a caulking step of caulking a portion of the second conductive component onto the current collecting component after the insertion step in a state where a supporting fixture is in contact with a portion of the terminal closer to the outer periphery than the rib.

[0111] Item 10: The manufacturing method according to Item 9, wherein in the inserting step, the terminal has the ultrasonic bonding portion between the first conductive member and the second conductive member.

[0112] Item 11: A manufacturing method according to Item 9 or 10, wherein the second conductive component of the terminal has a hollow cylindrical portion, and when a region of the first conductive component that overlaps with the cylindrical portion in a direction in which the cylindrical portion extends is taken as the first region, and a region that is located on the inner side of the first region and on which the ultrasonic bonding portion is formed is taken as the second region, the second region does not protrude toward the second surface side compared with the first region, and in the caulking step, the cylindrical portion of the second conductive component is caulked onto the current collecting component in a state in which a supporting fixture is in contact with the second surface side of the first region.

[0113] Item 12: The manufacturing method according to Item 11, wherein a thickness T1 of the first region and a thickness T2 of the second region of the terminal satisfy the following relationship: 0.8≤T1 / T2≤1.2.

[0114] Item 13: A manufacturing method according to Item 11 or Item 12, wherein the second conductive component of the terminal is made of copper or a copper alloy and has a flange portion, at least a portion of the flange portion is arranged in the recessed portion of the first conductive component, and a thickness T3 of the flange portion and a thickness T1 of the first region satisfy the following relationship: 3≤T3 / T1.

[0115] Item 14: The manufacturing method according to Item 11, wherein a thickness T1 of the first region and a thickness T2 of the second region of the terminal satisfy the following relationship: T1 / T2≤0.5.

[0116] Item 15: The manufacturing method according to any one of Items 9 to 14, wherein the terminal further includes a fastening portion that mechanically fastens the first conductive member and the second conductive member at a position closer to the outer peripheral side than the ultrasonic bonding portion.

[0117] Item 16: The manufacturing method according to any one of Items 9 to 15, wherein the terminal further comprises an external conductive component, and the manufacturing method further comprises an external conductive component mounting step of welding the external conductive component to the rib after the caulking step.

[0118] Description of Reference Numerals

[0119] 10 ... electrode body; 14 ... negative electrode current collecting member (current collecting member); 20 ... battery case; 24 ... cover; 40, 140, 240 ... negative electrode terminal (terminal); 40c ... caulking portion; 41, 141, 241 ...

[0120] 1st conductive member; 41d...lower surface (1st surface); 41r...1st recessed portion; 41t...thin-walled portion;

[0121] 41s... rib; 42, 142, 242... second conductive member; 42f, 142f... flange portion; 42n...

[0122] Contraction portion (portion disposed in the recess); 42p ... cylindrical portion; 43, 143 ... fastening portion;

[0123] 45, 245…ultrasonic bonding portion; 100…power storage device; 200…power storage module.

Claims

1. A terminal for an electric storage device, characterized in that: have: A first conductive member is made of a first metal and has a recessed portion on a first surface; a second conductive member, made of a second metal different from the first metal, and having a portion disposed in the recess; as well as an ultrasonic bonding portion for ultrasonically bonding the first conductive member and the second conductive member, The first conductive member includes a rib that is provided on an outer peripheral side of the ultrasonic bonding portion and protrudes from a second surface of the first conductive member that is opposite to the first surface.

2. The terminal for an electric storage device according to claim 1, wherein: The second conductive member has a hollow cylindrical portion. When a region of the first conductive component that overlaps with the cylindrical portion in a direction in which the cylindrical portion extends is defined as a first region, and a region located inside the first region and having the ultrasonic bonding portion formed therein is defined as a second region, the rib is disposed between the first region and the second region.

3. The terminal for an electric storage device according to claim 2, wherein: The second region does not protrude toward the second surface side as much as the first region.

4. The terminal for an electric storage device according to claim 2 or 3, characterized in that: The thickness T1 of the first region and the thickness T2 of the second region satisfy the following relationship: 0.8≤T1 / T2≤1.

2.

5. The terminal for an electric storage device according to claim 2 or 3, characterized in that: The second conductive member is made of copper or copper alloy and has a flange portion. At least a portion of the flange portion is disposed in the recessed portion of the first conductive member. The thickness T3 of the flange portion and the thickness T1 of the first region satisfy the following relationship: 3≤T3 / T1.

6. The terminal for an electric storage device according to claim 2 or 3, characterized in that: The thickness T1 of the first region and the thickness T2 of the second region satisfy the following relationship: T1 / T2≤0.

5.

7. The terminal for an electric storage device according to any one of claims 1 to 3, characterized in that: A fastening portion is further provided for mechanically fastening the first conductive member and the second conductive member at a position on the outer peripheral side of the ultrasonic bonding portion.

8. The terminal for an electric storage device according to any one of claims 1 to 3, characterized in that: An external conductive member is further provided which is joined to the rib of the first conductive member by welding.

9. A method for manufacturing an electric storage device, the electric storage device comprising: An electrode body having a first electrode and a second electrode having a polarity different from that of the first electrode; A battery housing for housing the electrode body; a terminal electrically connected to the first electrode and mounted on the battery case; as well as a current collecting member having a hole and electrically connecting the first electrode and the terminal inside the battery case, The terminal has: A first conductive member is made of a first metal and has a recessed portion on a first surface; a second conductive member, made of a second metal different from the first metal, and having a portion disposed in the recess; as well as an ultrasonic bonding portion for ultrasonically bonding the first conductive member and the second conductive member, The first conductive member includes a rib, the rib being provided on the outer peripheral side of the ultrasonic bonding portion and protruding from a second surface of the first conductive member on the opposite side to the first surface. It is characterized in that The method for manufacturing the power storage device comprises: an inserting step of inserting a portion of the second conductive member of the terminal into the hole of the current collecting member; and and a caulking step of caulking a portion of the second conductive member onto the current collecting member in a state where a supporting jig is in contact with a portion of the terminal on an outer peripheral side of the rib after the inserting step.

10. The method for manufacturing an electric storage device according to claim 9, wherein: In the inserting step, the terminal has the ultrasonic bonding portion between the first conductive member and the second conductive member.

11. The method for manufacturing an electric storage device according to claim 9, wherein: The second conductive member of the terminal has a hollow cylindrical portion. When a region of the first conductive member that overlaps with the cylindrical portion in the direction in which the cylindrical portion extends is defined as a first region, and a region located inside the first region and having the ultrasonic bonding portion formed therein is defined as a second region, the second region does not protrude toward the second surface side compared to the first region. In the caulking step, the cylindrical portion of the second conductive member is caulked onto the current collecting member in a state where a supporting jig is in contact with the second surface side of the first region.

12. The method for manufacturing an electric storage device according to claim 11, wherein: A thickness T1 of the first region and a thickness T2 of the second region of the terminal satisfy the following relationship: 0.8≤T1 / T2≤1.

2.

13. The method for manufacturing an electric storage device according to claim 11, wherein: The second conductive member of the terminal is made of copper or copper alloy and has a flange portion. At least a portion of the flange portion is disposed in the recessed portion of the first conductive member. The thickness T3 of the flange portion and the thickness T1 of the first region satisfy the following relationship: 3≤T3 / T1.

14. The method for manufacturing an electric storage device according to claim 11, wherein: A thickness T1 of the first region and a thickness T2 of the second region of the terminal satisfy the following relationship: T1 / T2≤0.

5.

15. The method for manufacturing an electric storage device according to any one of claims 9 to 14, characterized in that: The terminal further includes a fastening portion that mechanically fastens the first conductive member and the second conductive member at a position on the outer peripheral side of the ultrasonic bonding portion.

16. The method for manufacturing an electric storage device according to any one of claims 9 to 14, characterized in that: The terminal also has an external conductive member, The method for manufacturing an electric storage device further includes an external conductive member mounting step of welding and joining the external conductive member to the rib after the caulking step.

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