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

Abstract

The present invention relates to a method for manufacturing a terminal for a power storage device and a method for manufacturing a power storage device, wherein the connection state of a first conductive member and a second conductive member is stable. According to the present invention, the terminal is provided with: a first conductive member comprising a first metal and having a recess and a through-hole; 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 around the through hole. The manufacturing method includes: a disposing step of disposing a portion of the second conductive member in the recess of the first conductive member; and a bonding step for ultrasonically bonding the periphery of the through-hole of the first conductive member and the second conductive member.

Description

Technical Field

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

[0002] In the past, it is known that there is a terminal formed by joining conductive parts (a first conductive part and a second conductive part) made of different types of metals (for example, refer to Japanese Patent Application Publication No. 2011-124024 and Japanese Patent Application Publication No. 2022-049729). For example, Japanese Patent Application Publication No. 2011-124024 discloses a method for manufacturing a terminal, including: an ultrasonic joining step of ultrasonically joining a first conductive part and a second conductive part to form an ultrasonic joining portion; and a caulking step of caulking (mechanically fastening) the first conductive part and the second conductive part to form a fastening portion.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2011-124024

[0004] Patent Document 2: Japanese Patent Application Publication No. 2022-049729

[0005] In ultrasonic bonding, a horn is crimped to one of the conductive components to apply a press load and impart ultrasonic vibration. According to the research of the present inventors, undesirable deformation and distortion may occur in the conductive component to which the horn is crimped. Furthermore, it may be difficult to perform caulking, or the previously formed fastening portion may be damaged, making it difficult to stabilize the connection state between the first conductive component and the second conductive component. Summary of the invention

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a terminal for an electric storage device and a method for manufacturing an electric storage device in which the connection state between a first conductive member and a second conductive member is easily stabilized.

[0007] According to the present invention, there is provided a method for manufacturing a terminal for a power storage device, the terminal for a power storage device comprising: a first conductive component, which is made of a first metal and has a recessed portion and a through hole provided in the 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; an ultrasonic bonding portion, which ultrasonically bonds the first conductive component to the second conductive component around the through hole; and a fastening portion, which mechanically fastens the first conductive component to the second conductive component on the outer peripheral side of the ultrasonic bonding portion. The above-mentioned manufacturing method comprises: a configuration step, which configures a portion of the second conductive component in the recessed portion of the above-mentioned first conductive component; and a bonding step, which ultrasonically bonds the periphery of the through hole of the above-mentioned first conductive component to the above-mentioned second conductive component after the above-mentioned configuration step.

[0008] According to the above-described manufacturing method, a state in which the connection state between the first conductive member and the second conductive member is stable can be preferably achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a perspective view schematically showing a power storage device according to an embodiment.

[0010] Figure 2 It is along Figure 1 Schematic longitudinal cross-sectional view along line II-II.

[0011] Figure 3 It is a partial enlarged cross-sectional view schematically showing the vicinity of the negative electrode terminal.

[0012] Figure 4 It is a perspective view schematically showing a negative electrode terminal according to one embodiment.

[0013] Figure 5 yes Figure 4 Schematic side view of the negative terminal of .

[0014] Figure 6 It is along Figure 4 A schematic longitudinal cross-sectional view along line VI-VI of FIG.

[0015] Figure 7 It is schematically indicated Figure 6 A partial enlarged cross-sectional view of the main parts.

[0016] Figure 8 It is a perspective view schematically showing a battery pack according to one embodiment.

[0017] Fig. 9 It is a longitudinal sectional view schematically showing an example of a joining process.

[0018] Fig.10 This is a longitudinal sectional view schematically showing an example of the caulking step.

[0019] Fig.11 (A) is a top view schematically showing an ultrasonic bonding portion according to a modification example. Fig.11 (B) is an explanatory diagram for explaining the relationship between the vibration direction and the arrangement of the welding head.

[0020] Fig.12 (A) is the first variant example involved in Fig.10 Quite a picture, Fig.12 (B) is the second variant example involved in Fig.10 Quite a picture. DETAILED DESCRIPTION

[0021] 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.

[0022] <Electricity Storage Device 100>

[0023] First, the power storage device manufactured by the manufacturing method disclosed herein is described. In this specification, "power storage device" refers to all devices 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.

[0024] Figure 1 It is a perspective view of the power storage device 100 . Figure 2 It is along Figure 1 Schematic longitudinal cross-sectional view of line II-II. 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.

[0025] like Figure 2As shown, the power storage device 100 includes an electrode body 10, 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.

[0026] The electrode body 10 can be the same as in the past, without any 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".

[0027] The positive electrode has a positive electrode collector 11 and a positive electrode mixture layer (not shown) fixed to 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 to 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).

[0028] like Figure 2 As 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 a conductive metal such as aluminum, aluminum alloy, nickel, stainless steel, etc. The positive electrode collector component 13 electrically connects the positive electrode to the positive terminal 30 inside the battery case 20.

[0029] 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 (negative electrode collector exposed portion) on which the negative electrode mixture layer is not formed protrudes from the stacked portion. A negative electrode collector component 14 is attached to the negative electrode collector exposed portion. The material (metal type) of the negative electrode collector component 14 may be different from that of the positive electrode collector component 13. The negative electrode collector component 14 may 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 negative electrode collector component 14 electrically connects the negative electrode to the negative terminal 40 inside the battery case 20.

[0030] The electrolyte can be the same as in the past and is not particularly limited. The electrolyte is, for example, a non-aqueous liquid electrolyte (non-aqueous electrolyte) containing a non-aqueous solvent and an auxiliary salt. The non-aqueous solvent includes, for example, carbonates such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. The auxiliary salt is, for example, LiPF 6 However, the electrolyte may be integrated with the electrode body 10 in a solid state (solid electrolyte).

[0031] 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 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).

[0032] 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.

[0033] like Figure 1As 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".

[0034] like Figure 2 As shown, the positive terminal 30 is electrically connected to the positive electrode of the electrode body 10 via the positive electrode collector 13 inside the 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.

[0035] 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.

[0036] like Figure 3 As shown, a terminal lead-out hole 24h is formed in the cover body 24 and penetrates in the up-down direction Z. Preferably, the terminal lead-out hole 24h is provided in the cover body 24. Although not shown in the figure, the terminal lead-out hole 24h is circular (e.g., a perfect circle) in a plan view. The terminal lead-out 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-out hole 24h is formed to be smaller than the flange portion 42f of the negative terminal 40 described later.

[0037] 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".

[0038] 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.

[0039] 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.

[0040] 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.

[0041] <Negative terminal 40>

[0042] 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, by means of a fastening portion 43 and an ultrasonic bonding portion 45. 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. In addition, it is preferred to weld the crimping portion 40c to the negative current collector 14.

[0043] Figure 4 It is a schematic perspective view of the negative electrode terminal 40 before being attached to the lid body 24 (that is, before caulking). Figure 5 yes Figure 4 Schematic side view of the negative terminal 40. Figure 6 It is along Figure 4 A schematic longitudinal cross-sectional view along line VI-VI of FIG. Figure 7 It is schematically indicated Figure 6 A partial enlarged cross-sectional view of the main parts of the Figure 6As shown, the negative electrode terminal 40 includes a first conductive member 41, a second conductive member 42, a fastening portion 43, and an ultrasonic bonding 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 ultrasonic bonding portion 45.

[0044] 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).

[0045] The first conductive member 41 is preferably in a plate shape (specifically, a flat plate shape). Figure 4 As shown, here, in a plan view, the first conductive component 41 is a substantially rectangular shape having short sides and long sides. Figure 6 As shown, the thickness T1 of the first conductive component 41 is preferably 0.5 to 5 mm, more preferably 1 to 3 mm, for example 1.8 mm. The thickness T1 of the first conductive component 41 is preferably less than the length of the short side when viewed from above. 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 side away from the battery case 20 and the second conductive component 42.

[0046] like Figure 4 , Figure 5 As shown, the first conductive component 41 is divided into two regions in the longitudinal direction Y, and has a connecting portion 41a electrically connected to the second conductive component 42 and a side extending from the connecting portion 41a in the longitudinal direction Y ( Figure 4 The extension portion 41b extends to the left of the Figure 6 As shown, here, the connection portion 41a has a first recess 41r, a through hole 41h, a thin portion 41t, and a second recess 41c. However, in other embodiments, the connection portion 41a may not have the thin portion 41t and / or the second recess 41c.

[0047] like Figure 6As shown, the first recess 41r is provided on the lower surface (first face) 41d. Although not shown in the figure, here, in a plan view, the first recess 41r is annular (e.g., circular) surrounding the through hole 41h. Although not particularly limited, it is preferred that the outer diameter (the diameter in the case of a perfect circle, the shortest length through the center in the case of a non-perfect circle) Wr of the first recess 41r is, for example, 6 mm or more. Here, the first recess 41r is formed into 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). The flange portion 42f (specifically, the contraction portion 42n) of the second conductive component 42 described later is inserted into the first recess 41r. The first recess 41r is an example of a "recess on the first face".

[0048] like Figure 4 As shown, the through hole 41h is provided in the first recess 41r. The through hole 41h penetrates the first conductive component 41 in the up-down direction Z. The through hole 41h is preferably provided in the thin-walled portion 41t, and more preferably provided in the central portion of the thin-walled portion 41t. In the upper surface 41u of the first conductive component 41, the second conductive component 42 (specifically, the flange portion 42f described later) is exposed from the through hole 41h. Here, the through hole 41h is circular (e.g., a perfect circle) when viewed from above. Although not particularly limited, as Figure 6 As shown, the outer diameter (in the case of a perfect circle, the diameter; in the case of a non-perfect circle, the shortest length passing through the center) Wh of the through hole 41h is typically smaller than the outer diameter Wr of the first recess 41r, and is preferably 5 to 7 mm. The through hole 41h is provided on the inner circumference side (center side) of the fastening portion 43 and the ultrasonic bonding portion 45.

[0049] like Figure 4 As shown in FIG. 4 , the thin-walled portion 41t is provided around the through hole 41h. Here, the thin-walled portion 41t is annular (eg, circular) in a plan view. Figure 6As shown in FIG. 1 , the thin-walled portion 41t is formed to be thinner than its outer peripheral portion (e.g., the extension portion 41b). That is, the thickness Tt of the thin-walled portion 41t is smaller than the thickness T1 of the first conductive member 41. Here, the thickness Tt of the thin-walled portion 41t is smaller than the thickness Tf of the portion of the flange portion 42f described later that protrudes from the first recess 41r. Here, the thin-walled portion 41t is a region where the first recess 41r and the second recess 41c overlap in a plan view. It is preferred that the thin-walled portion 41t is provided by forming the second recess 41c on the surface (i.e., the upper surface 41u) on the opposite side of the lower surface 41d on which the first recess 41r is formed as in the present embodiment. Although not particularly limited, it is preferred that the outer diameter Wt (diameter in the case of a perfect circle, the shortest length passing through the center in the case of a non-perfect circle) of the thin-walled portion 41t is, for example, 7 to 14 mm. Here, the outer diameter Wt of the thin-walled portion 41t is smaller than the outer diameter Wr of the first recess 41r. The thin-walled portion 41t is provided with the ultrasonic bonding portion 45. Thus, the ultrasonic bonding portion 45 can be formed more stably.

[0050] The second recess 41c is provided on the upper surface (second surface) 41u. Figure 4 As shown, here, in a plan view, the second recess 41c is annular (e.g., circular) surrounding the through hole 41h. Although not particularly limited, here, in a plan view, the outer diameter of the second recess 41c (here, the same as the outer diameter Wt of the thin-walled portion 41t, the diameter in the case of a perfect circle, and the shortest length passing through the center in the case of a non-perfect circle) is smaller than the outer diameter Wr of the first recess 41r.

[0051] The extension portion 41b is used, for example, to electrically connect a plurality of power storage devices 100 to form a battery pack 200 (see Figure 8 ) is provided as a bus bar 90 as a conductive member (refer to Figure 8 By providing the extension portion 41 b, a sufficient grounding area with the bus bar 90 can be ensured, and the conduction reliability of the battery pack 200 can be improved.

[0052] 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.

[0053] like Figure 5 , Figure 6 As shown, the second conductive component 42 has an axis C. 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. Preferably, the flange portion 42f of the second conductive component 42 is arranged in the first recess 41r of the first conductive component 41.

[0054] 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 in FIG. 1 , 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 a substantially cylindrical shape. Figure 6 As shown, the axis of the flange portion 42f coincides with the axis C of the second conductive component 42. The thickness Tf of the portion of the flange portion 42f protruding from the first recess 41r is preferably 0.5 to 5 mm, more preferably 1 to 3 mm, for example 2.0 mm. Here, the thickness Tf is greater than the thickness T1 of the first conductive component 41. It is preferred that the thickness Tf of the portion of the flange portion 42f protruding from the first recess 41r and the thickness Tt of the thin-walled portion 41t of the first conductive component 41 satisfy the following formula: Tf / Tt>3. Thus, a high-strength ultrasonic bonding portion 45 can be formed more stably. 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.

[0055] 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".

[0056] 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 through the terminal lead-out hole 24h of the cover 24. Figure 5 , Figure 6 As shown, here, the outer shape of the shaft portion 42s is cylindrical. The axis of the shaft portion 42s is consistent with the axis C of the second conductive component 42. Before the caulking process, the lower end of the shaft portion 42s, that is, the end on the opposite side 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. 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 a portion that is expanded by the caulking process to constitute the caulking portion 40c when the negative terminal 40 is installed on the cover body 24. Preferably, the cylindrical portion 42p is electrically connected to the negative electrode collector 14 inside the battery case 20 by the caulking process.

[0057] The fastening portion 43 is a connecting portion that mechanically fastens the first conductive component 41 and the second conductive component 42. The fastening portion 43 is arranged on the outer peripheral side of the ultrasonic bonding portion 45 in the radial direction of the through hole 41h. Here, the fastening portion 43 is configured so that a part 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 42o of the flange portion 42f of the second conductive component 42. Thus, the strength of the fastening portion 43 can be improved. Here, the fastening portion 43 is continuously formed. Here, the fastening portion 43 is annular (for example, circular) when viewed from above. This can improve the strength of the fastening portion 43 and enhance the conduction reliability of the negative electrode terminal 40 .

[0058] 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, shrink fitting, caulking, riveting, folding, bolting, etc. In some preferred embodiments, the fastening portion 43 is 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. Thus, for example, even if the first conductive component 41 and the second conductive component 42 are made of different types of metals, the first conductive component 41 and the second conductive component 42 can be appropriately fixed. The fastening portion 43 may also be, for example, a press-fit fitting portion where the contracted portion 42n of the second conductive component 42 is fitted into the first recessed portion 41r of the first conductive component 41 by press-fitting.

[0059] The ultrasonic bonding part 45 is a metal bonding part formed by ultrasonic bonding of the first conductive member 41 and the second conductive member 42. The ultrasonic bonding part 45 is arranged around the through hole 41h. Here, the ultrasonic bonding part 45 is arranged at a position separated from the through hole 41h. Here, the ultrasonic bonding part 45 is arranged at the thin-walled part 41t. Here, the ultrasonic bonding part 45 is arranged at a position separated from the fastening part 43. The ultrasonic bonding part 45 is arranged on the inner peripheral side (center side) of the fastening part 43 in the radial direction of the through hole 41h. The ultrasonic bonding part 45 can be a bonding part with a relatively lower strength (brittle) than the fastening part 43. By arranging such an ultrasonic bonding part 45 on the inner peripheral side of the fastening part 43, the ultrasonic bonding part 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 part 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.

[0060] The ultrasonic bonding portion 45 is formed continuously or intermittently in a plan view. Preferably, the ultrasonic bonding portion 45 is formed to be axially symmetrical with respect to the axis C of the second conductive member 42 (for example, the flange portion 42f). Figure 4 As shown, the ultrasonic bonding part 45 is preferably formed continuously along the circumferential direction of the through hole 41h. The ultrasonic bonding part 45 is preferably annular (eg, circular) in a plan view. This can improve the strength of the ultrasonic bonding part 45 and improve the conduction reliability of the negative terminal 40.

[0061] As described above, the negative terminal 40 includes two types of connection parts with different connection methods, namely, the ultrasonic bonding part 45 and the fastening part 43 provided on the outer peripheral side of the ultrasonic bonding part 45. As a result, the first conductive member 41 and the second conductive member 42 are easily maintained in a close contact state. Therefore, the conductive connection between the first conductive member 41 and the second conductive member 42 can be stably ensured, and the conductive reliability of the negative terminal 40 can be improved.

[0062] <Method for Manufacturing Negative Electrode Terminal 40>

[0063] 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 a joining step of ultrasonically joining the first conductive component 41 and the second conductive component 42. By performing the joining step after the fastening step, an ultrasonically stable joint 45 can be formed with high precision. However, the order of the fastening step and the joining step can be reversed or performed approximately simultaneously. In addition, the manufacturing method disclosed herein may also include other steps at any stage.

[0064] 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 a fastening portion 43. This process includes a configuration process of configuring a portion of the second conductive component 42 (for example, a portion including the contraction portion 42n) in the first recess 41r of the first conductive component 41. In other words, a configuration process is also provided. For example, the fastening portion 43 can be formed by configuring 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 using the second conductive component 42. As a result, 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. For example, it can be formed by horizontally press-fitting the constricted portion 42n of the second conductive member 42 into the first recessed portion 41r of the first conductive member 41. This can improve the workability of the fastening step.

[0065] In the joining process, the periphery of the through hole 41h of the first conductive component 41 is ultrasonically joined to the second conductive component 42 in a state where a part of the second conductive component 42 is arranged in the first recess 41r of the first conductive component 41, thereby forming an ultrasonic joint portion 45. In ultrasonic joining, it is difficult to generate brittle intermetallic compounds at the joining interface between the first conductive component 41 and the second conductive component 42, for example, compared with laser welding. Therefore, a high-strength metal joint portion can be stably formed. In several preferred embodiments, the ultrasonic joint portion 45 is formed by ultrasonically joining the thin-walled portion 41t of the first conductive component 41 to the second conductive component 42 (for example, the flange portion 42f). Thus, the ultrasonic joint portion 45 is easily and stably formed. In addition, since less energy is required during joining, the deformation and deformation of the first conductive component 41 can be suppressed to a smaller extent.

[0066] Fig. 9 It is a longitudinal sectional view schematically showing this process. In several preferred embodiments, an ultrasonic bonding device having a welding head 81 and an anvil 82 (supporting jig: receiving jig) is first prepared. The welding head 81 has an annular foot 81a. Although omitted from the figure, the welding head 81 is installed in a punching device and an ultrasonic oscillation device. The welding head 81 is configured to impart ultrasonic vibration to the body to be joined in a specified vibration direction. The anvil 82 is installed in the punching device in a manner opposite to the welding head 81. Here, the anvil 82 has an outer shape that can be accommodated in the cylindrical portion 42p (hollow portion) of the second conductive component 42.

[0067] Next, if Fig. 9As shown, the periphery of the through hole 41h of the first conductive component 41 (here, the thin-walled portion 41t) and the portion of the second conductive component 42 disposed in the first recess 41r of the first conductive component 41 (here, a portion of the flange portion 42f) are clamped by the welding head 81 and the anvil 82. In this embodiment, the foot 81a of the welding head 81 is brought into contact with the thin-walled portion 41t of the first conductive component 41, and the anvil 82 is brought into contact with the shaft portion 42s of the second conductive component 42. The anvil 82 is inserted into the cylindrical portion 42p of the second conductive component 42. In this state, the welding head 81 applies ultrasonic vibration while applying a press load. As a result, the first conductive component 41 to which the welding head 81 is crimped vibrates synchronously with the welding head 81.

[0068] The conditions of the press-in load and ultrasonic vibration are design matters that can be appropriately adjusted according to the material, size, shape of the welding head 81, etc. of the first conductive component 41 or the second conductive component 42, for example. Therefore, although not particularly limited, in several embodiments, the press-in load is preferably approximately 500 to 2000N, and more preferably 800 to 1200N. The frequency of the ultrasonic vibration imparted to the first conductive component 41 by the welding head 81 is preferably approximately 10 to 50kHz, and more preferably 15 to 25kHz. In addition, the oscillation time of the ultrasonic vibration is preferably approximately 0.5 to 1.5sec, and more preferably 0.7 to 1.0sec. In addition, the vibration direction of the welding head 81 can be, for example, the short side direction X or the long side direction Y.

[0069] By ultrasonic vibration, in the area where the force of the welding head 81 is applied, the bonding interface between the first conductive component 41 (here, the thin-walled portion 41t) and the second conductive component 42 (here, the flange portion 42f) is solid-phase welded. As a result, an ultrasonic bonding portion 45 is formed around the through hole 41h. Here, since the foot portion 81a of the welding head 81 is annular, the ultrasonic bonding portion 45 is formed continuously (annularly) along the circumference of the through hole 41h. In some embodiments, such as Figure 6 As shown, for example, the inner diameter Wi of the ultrasonic bonding portion 45 is preferably 7 to 12 mm, and the outer diameter Wo of the ultrasonic bonding portion 45 is preferably 8 to 13 mm.

[0070] By making a state where a part of the second conductive component 42 is arranged in the first recess 41r of the first conductive component 41, the reliability of the connection between the first conductive component 41 and the second conductive component 42 when the terminal is formed is improved. In addition, by performing ultrasonic bonding around the through hole 41h as in the embodiment, even in the state where a part of the second conductive component 42 is arranged in the first recess 41r of the first conductive component 41, the ultrasonically bonded area in the first conductive component 41 can be smoothly vibrated. Therefore, less energy is sufficient, and the first conductive component 41 is difficult to deform. In addition, even if the first conductive component 41 is deformed, the deformation can be absorbed by the through hole 41h (absorbing wall flow), and the generation of undesirable deformation and deformation in the first conductive component 41 can be suppressed. Therefore, a stable state of the connection state between the first conductive component 41 and the second conductive component 42 can be appropriately achieved. Therefore, a terminal or power storage device with higher reliability is achieved. Furthermore, when the first conductive member 41 and the second conductive member 42 are ultrasonically bonded, it is particularly effective when the first conductive member 41 and the second conductive member 42 are fixed by the fastening portion 43 on the outer peripheral side of the ultrasonic bonding portion.

[0071] In the first embodiment, when the width of the thin-walled portion 41t is, for example, 7 mm or more, or further as large as 10 mm or more, it is preferred to crimp the foot 81a of the welding head 81 near the through hole 41h. Thus, the through hole 41h and the thin-walled portion 41t can be used to absorb stress, and the first conductive component 41 can vibrate more smoothly. In addition, it is possible to better suppress undesirable large deformation of the first conductive component 41. In addition, by forming an ultrasonic bonding portion 45 near the through hole 41h (in other words, forming the ultrasonic bonding portion 45 at a position away from the fastening portion 43), it is possible to reduce the stress from the bus bar 90 (see Figure 8 Therefore, even if external forces such as vibration and impact are applied when the power storage device 100 is used, the conductive connection between the first conductive component 41 and the second conductive component 42 can be stably ensured, and the conductive reliability of the negative terminal 40 can be improved.

[0072] Based on the above viewpoints, in the first embodiment, if Figure 7As shown, when the distance between the through hole 41h and the inner periphery of the ultrasonic bonding part 45 is set to D1 and the distance between the outer periphery of the ultrasonic bonding part 45 and the outer periphery of the thin-walled part 41t is set to D2 in the radial direction of the through hole 41h, the ultrasonic bonding part 45 is preferably formed in a manner that D1 is smaller than D2. That is, D1<D2 is preferably formed. By making the ultrasonic bonding part 45 close to the through hole 41h in this way, a high-strength ultrasonic bonding part 45 can be formed more stably, and the above-mentioned effect can be exerted at a higher level. According to the above viewpoint, D1 / D2 is preferably less than 1, more preferably less than 0.8, and further preferably less than 0.5. D1 is, for example, preferably less than 5 mm, more preferably less than 3 mm, and further preferably less than 1 mm. In addition, in the radial direction of the through hole 41h, the ratio (W2 / W1) of the width W2 of the thin-walled part 41t to the width W1 of the ultrasonic bonding part 45 is preferably greater than 1, and more preferably greater than 1.

[0073] In addition, in the first embodiment, if Figure 6 As shown, the difference (Wi-Wh) between the inner diameter Wi of the ultrasonic bonding portion 45 and the outer diameter Wh of the through hole 41h is preferably 5 mm or less, and more preferably 2 mm or less. The ultrasonic bonding portion 45 is preferably separated from the through hole 41h. The above difference (Wi-Wh) is preferably 0.1 mm or more. In addition, it is preferred that the outer diameter Wt of the thin-walled portion 41t, the outer diameter Wh of the through hole 41h, the inner diameter Wi of the ultrasonic bonding portion 45, and the outer diameter Wo satisfy the following formula: (Wt-Wo) / (Wi-Wh)>1.

[0074] The ratio (Wt / Wh) of the outer diameter Wt of the thin portion 41t to the outer diameter Wh of the through hole 41h is preferably 2 or more, and more preferably 3 or more. By making the thin portion 41t larger in this way, the ultrasonic bonding portion 45 can be formed more stably.

[0075] In the second embodiment, when the through hole 41h is as large as 5 mm or more, for example, the foot 81a of the welding head 81 is preferably pressed against the outer periphery of the through hole 41h and the vicinity of the outer periphery of the thin-walled portion 41t. In the technology disclosed here, since the flow of the through hole 41h can be absorbed by the wall, the ultrasonic bonding portion 45 can be formed to the limit of the through hole 41h and the thin-walled portion 41t. As a result, the area of ​​the ultrasonic bonding portion 45 can be used to reduce the conduction resistance and lower the resistance. In addition, 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.

[0076] Based on the above viewpoints, in the second embodiment, if Figure 7As shown, in the radial direction of the through hole 41h, the distance D1 between the through hole 41h and the inner peripheral edge of the ultrasonic bonding portion 45 is preferably 5 mm or less, more preferably 3 mm or less, and further preferably 1 mm or less. In addition, in the radial direction of the through hole 41h, the ratio (W1 / W2) of the width W1 of the ultrasonic bonding portion 45 to the width W2 of the thin-walled portion 41t is preferably 0.5 or more, more preferably 0.7 or more. As a result, the on-resistance can be further reduced and the resistance can be further reduced. In addition, the resistance heating can be suppressed to a lower level.

[0077] In addition, in the second embodiment, Figure 6 As shown, the difference (Wi-Wh) between the inner diameter Wi of the ultrasonic bonding portion 45 and the outer diameter Wh of the through hole 41h is preferably 5 mm or less, and more preferably 2 mm or less. The ultrasonic bonding portion 45 is preferably far away from the through hole 41h. The above difference (Wi-Wh) is preferably 0.1 mm or more. In addition, the difference (Wt-Wo) between the outer diameter Wt of the thin-walled portion 41t and the outer diameter Wo of the ultrasonic bonding portion 45 is preferably 5 mm or less, and more preferably 2 mm or less. The ultrasonic bonding portion 45 is preferably far away from the outer edge of the thin-walled portion 41t. The above difference (Wt-Wo) is preferably 0.1 mm or more. Contrary to the first embodiment, it is preferred that the outer diameter Wt of the thin-walled portion 41t, the outer diameter Wh of the through hole 41h, the inner diameter Wi of the ultrasonic bonding portion 45, and the outer diameter Wo satisfy the following formula: (Wt-Wo) / (Wi-Wh)<1.

[0078] Furthermore, the ratio (Wt / Wh) of the outer diameter Wt of the thin portion 41t to the outer diameter Wh of the through hole 41h is preferably 2 or more, and more preferably 3 or more. By enlarging the through hole 41h in this way, the above-mentioned effect can be exerted at a higher level.

[0079] <Method of Manufacturing Power Storage Device 100>

[0080] The power storage device 100 is characterized by using the positive terminal 30 and / or the negative terminal 40 manufactured by the above-mentioned manufacturing method. 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 above-mentioned electrode body 10, electrolyte, case body 22, cover body 24, positive terminal 30 and negative terminal 40 and using a manufacturing method including a mounting process and a case joining process in sequence.

[0081] In the 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 3As shown, the negative terminal 40 and the negative electrode current collector 14 are fixed to the cover 24 by riveting. In several preferred embodiments, this process includes an insertion process and a riveting process in sequence. In the insertion process, a portion of the second conductive component 42 of the negative terminal 40 (here, the shaft portion 42s before riveting) is inserted into the hole portion 14h of the negative electrode current collector 14. In detail, the shaft portion 42s of the negative terminal 40 before riveting is passed through the cylindrical portion 51 of the gasket 50, the terminal lead-out hole 24h of the cover 24, the hole portion 60h of the insulating member 60, and the hole portion 14h of the negative electrode current collector 14 from the top of the cover 24. As a result, the cylindrical portion 42p of the negative terminal 40 protrudes downward from the hole portion 14h of the negative electrode current collector 14.

[0082] 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.

[0083] Fig.10 is a longitudinal sectional view schematically showing an example of this process. Fig.10 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 Fig.10 As shown, a caulking device having a punch (punching jig) 91 and a die (supporting jig) 92 is prepared. Here, the die 92 has a flat surface. Next, the negative terminal 40 is arranged on the flat surface of the die 92 in an upside-down state. As a result, the upper surface 41u of the first conductive component 41 (at least the connecting portion 41a) is opposite to the die 92. The thin-walled portion 41t of the first conductive component 41 floats from the die 92. The second conductive component 42 does not abut against the die 92.

[0084] Next, the tip of the punch 91 is inserted into the cylindrical portion 42p (hollow portion) of the second conductive member 42. Fig.10 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.

[0085] In this embodiment, the first conductive member 41 has a second recess 41c on the upper surface 41u. Fig.10 When the area overlapping with the cylindrical portion 42p in the up-down direction (Z) is taken as the first area A1, and the area where the ultrasonic bonding portion 45 is formed is taken as the second area A2, the first area A1 protrudes downward (in the direction away from the second conductive component 42) than the second area A2. The downward direction is an example of "a direction perpendicular to the surface of the battery case on which the terminal is installed." Here, the first area A1 is an annular area overlapping with the cylindrical portion 42p when viewed from above. Here, most of the first area A1 is in contact with the die 92. The second area A2 is an area on the inner circumference side (close to the through hole 41h) than the first area A1.

[0086] Since the first area A1 protrudes downwards compared to the second area A2, the die 92 can bear directly below the cylindrical part 42p, so it is easy to perform caulking on the cylindrical part 42p. In addition, since the second area A2 is recessed (located above) compared to the first area A1, it is difficult to apply the compressive force of the caulking process to the area where the ultrasonic bonding part 45 is formed. Therefore, the load on the ultrasonic bonding part 45 can be reduced, and the situation that the ultrasonic bonding part 45 is damaged can be effectively suppressed.

[0087] 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. 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. Similarly, the positive electrode collector member 13 is welded to the positive electrode collector exposed portion of the positive electrode collector 11, so that the positive electrode of the electrode body 10 is electrically connected to the positive terminal 30. As a result, the cover 24, the positive terminal 30, the negative terminal 40 and the electrode body 10 are integrated.

[0088] 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.

[0089] 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, trucks, etc. The type of vehicle is not particularly limited, and examples thereof include a plug-in hybrid electric vehicle (PHEV), a hybrid electric vehicle (HEV), and a battery electric vehicle (BEV).

[0090] like Figure 8 As shown, the power storage device 100 can also be preferably used as a battery pack 200 in which a plurality of power storage devices 100 are electrically connected to each other via a bus bar 90. In this case, the electrical connection between the plurality of power storage devices 100 can be performed by, for example, arranging a flat bus bar 90 between the extension portions 41b of the first conductive member 41. 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 and the extension portion 41b can be electrically connected by welding such as laser welding.

[0091] 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 necessary, it can also be appropriately deleted.

[0092] (1) For example, in the above-mentioned embodiment, the fastening portion 43 is a fitting portion (for example, a press-fitting portion). However, the present invention is not limited thereto. The fastening portion 43 may be, for example, a caulking portion.

[0093] (2) For example, in the above-mentioned embodiment, the first conductive member 41 has a thin-walled portion 41t, and the ultrasonic bonding portion 45 is formed in the thin-walled portion 41t. The ultrasonic bonding portion 45 is provided at a position separated from the through hole 41h. However, this is not limited to this. The ultrasonic bonding portion 45 may be formed outside the thin-walled portion 41t, and may be formed along the outer edge of the through hole 41h.

[0094] (3) For example, in the above-mentioned embodiment, the ultrasonic bonding portion 45 is annular in plan view and is continuously formed along the circumference of the through hole 41h. However, it is not limited to this. The ultrasonic bonding portion 45 may also be composed of a plurality of parts, and the plurality of parts are respectively arranged at separate positions. Thus, since a space for the wall to escape can be ensured for the surface to which the press-in load is applied, the deformation and deformation of the first conductive component 41 can be suppressed to a smaller extent.

[0095] Fig.11 (A) is a top view schematically showing an ultrasonic bonding part 145 according to a modified example. The ultrasonic bonding part 145 is configured to include a plurality of (here, four) bonding portions 145a. Fig.11 As shown by the dotted lines in (A), spaces are respectively provided between the plurality of joining portions 145a. The plurality of joining portions 145a are respectively arranged at separated positions. Here, the plurality of joining portions 145a are of the same shape. Here, the plurality of joining portions 145a are respectively arc-shaped or straight-line-shaped. Preferably, the plurality of joining portions 145a are arranged in a ring shape with intervals. The plurality of joining portions 145a are preferably arranged at equal intervals, and more preferably are arranged point-symmetrically with respect to the center of the through hole 41h. Preferably, the ultrasonic joining portion 145 is a shape (dotted line ring shape) in which a local cutout is provided in the ring shape. Preferably, the plurality of joining portions 145a are arranged on a straight line extending through the center of the through hole 41h and avoiding the straight line extending along the vibration direction of the ultrasonic wave (here, the short side direction X or the long side direction Y). Here, the plurality of joining portions 145a are arranged in a straight line extending from the center of the through hole 41h toward the four corners of the rectangular first conductive component 41.

[0096] Such an ultrasonic bonding portion 145 can be formed by replacing the welding head 81 having the annular leg portion 81a in the above-mentioned bonding step with, for example, Fig.11 As shown in (B), a welding head 181 having a plurality of (here, 4) legs 181a is used. The lower surface of the leg 181a has a concave-convex structure in which protrusions and grooves are alternately formed. In this case, it is preferred that the leg 181a of the welding head 181 abuts against the first conductive component 41 in a manner that passes through the center of the through hole 41h and is not on a straight line extending along the ultrasonic vibration direction (here, the short side direction X or the long side direction Y). Thus, it is possible to suppress the first conductive component 41 from being deformed into an undesirable shape during ultrasonic bonding, and the vicinity of the ultrasonic bonding portion 45 is unlikely to deform or bulge.

[0097] (4) For example, in the above Fig.10In the embodiment, in the above-mentioned caulking process, the second conductive component 42 to be plastically deformed does not abut against the die (support fixture) 92. However, it is not limited to this. The second conductive component 42 may also abut against the die 92. In particular, when the Vickers hardness of the second conductive component 42 is greater than that of the first conductive component 41, such a structure can be particularly suitable.

[0098] Fig.12 (A) is the first variant example involved in Fig.10 Corresponding figure. In this modification, the die 192 of the caulking device has an outer shape that can be inserted into the through hole 41h of the first conductive component 41. The die 192 is inserted into the through hole 41h of the first conductive component 41 and abuts against the second conductive component 42 (specifically, the flange portion 42f). Here, the die 192 does not abut against the first conductive component 41. Preferably, the die 192 does not abut against the first conductive component 41. However, the die 192 can abut against a portion of the first conductive component 41. In this modification, a portion of the second conductive component 42 (the cylindrical portion 42p) is caulked while the die 192 abuts against the second conductive component 42, so that a portion of the second conductive component 42 is deformed to form a caulking portion 40c. By using the die 192, the ultrasonic bonding portion 45 does not overlap with the die 192 in the direction in which the compressive force is applied (here, the up and down direction Z). This makes it difficult for a load to be applied to the first conductive member 41 or the ultrasonic bonding portion 45. Therefore, it is possible to effectively suppress the occurrence of undesired distortion or deformation in the first conductive member 41. In addition, it is possible to effectively suppress damage to the ultrasonic bonding portion 45.

[0099] Fig.12 (B) is the second variant example involved in Fig.10 Corresponding figure. In this modified example, the die 292 of the caulking device has a protrusion 292c that can be inserted into the through hole 41h of the first conductive component 41. The protrusion 292c is inserted into the through hole 41h of the first conductive component 41 and abuts against the second conductive component 42 (specifically, the flange portion 42f). In addition, a portion of the die 292 also abuts against the first conductive component 41. Thus, since the second conductive component 42 can bear at least a portion of the load, the load on the first conductive component 41 or the ultrasonic bonding portion 45 can be reduced compared to the case where all the compressive force is applied to the first conductive component 41. Therefore, it is possible to effectively suppress the occurrence of undesirable deformation and deformation in the first conductive component 41. In addition, damage to the ultrasonic bonding portion 45 can be effectively suppressed.

[0100] (5) 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 and the negative electrode current collecting member 14 are electrically connected. However, the present invention is not limited thereto. The method of electrically connecting the negative electrode current collecting member 14 and the negative electrode terminal 40 may be, for example, mechanical fixing other than caulking, 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 method for manufacturing a terminal for a storage device, the terminal for a storage device comprising: a first conductive component, composed of a first metal, having a recess and a through hole provided in the recess on a first surface; a second conductive component, composed of a second metal different from the first metal, having a portion arranged in the recess; an ultrasonic bonding portion, ultrasonically bonding the first conductive component to the second conductive component around the through hole; and a fastening portion, mechanically fastening the first conductive component to the second conductive component on the outer peripheral side of the ultrasonic bonding portion, wherein the method for manufacturing a terminal for a storage device includes: a configuration step, configuring a portion of the second conductive component in the recess of the first conductive component; and a bonding step, after the configuration step, ultrasonically bonding the first conductive component to the second conductive component around the through hole.

[0103] Item 2: A manufacturing method according to Item 1, wherein a thin-walled portion is provided around the through hole of the first conductive component, the thickness of the thin-walled portion is thinner than the thickness of a portion on the outer peripheral side of the thin-walled portion, and in the bonding step, the thin-walled portion is ultrasonically bonded to the second conductive component.

[0104] Item 3: A manufacturing method according to Item 2, wherein, in the above-mentioned joining process, in the radial direction of the above-mentioned through hole, the distance D1 between the above-mentioned through hole and the inner peripheral edge of the above-mentioned ultrasonic joining portion is made smaller than the distance D2 between the outer peripheral edge of the above-mentioned ultrasonic joining portion and the outer peripheral edge of the above-mentioned thin-walled portion (D1<D2).

[0105] Item 4: A manufacturing method according to Item 2 or Item 3, wherein, in the above-mentioned joining step, ultrasonic joining is performed in a manner such that the ratio (W1 / W2) of the width W1 of the above-mentioned ultrasonic joining portion to the width W2 of the above-mentioned thin-walled portion in the radial direction of the above-mentioned through hole is greater than 0.5.

[0106] Item 5: The manufacturing method according to any one of Items 1 to 3, wherein the ultrasonic bonding portion is composed of a plurality of parts, and the plurality of parts are respectively arranged at separate positions.

[0107] Item 6: A method for manufacturing an electric storage device, the electric storage device comprising: an electrode body having a first electrode and a second electrode; a battery case accommodating the electrode body; a terminal mounted on the battery case; and a current collecting member electrically connecting the first electrode to the terminal inside the battery case, wherein the terminal comprises: a first conductive member composed of a first metal, having a recess on a first surface and a through hole disposed in the recess; a second conductive member composed of a second metal different from the first metal, having a through hole disposed in the recess part; an ultrasonic bonding part, ultrasonically bonding the first conductive component to the second conductive component around the through hole; and a fastening part, mechanically fastening the first conductive component to the second conductive component at an outer peripheral side than the ultrasonic bonding part, wherein the manufacture of the terminal includes: a configuration step, configuring a part of the second conductive component in the recessed portion of the first conductive component; and a bonding step, ultrasonically bonding the first conductive component to the second conductive component around the through hole after the configuration step.

[0108] Item 7: A manufacturing method according to Item 6, wherein a thin-walled portion is provided around the through hole of the first conductive component, the thickness of the thin-walled portion is thinner than the thickness of a portion on the outer peripheral side of the thin-walled portion, and in the bonding step, the thin-walled portion is ultrasonically bonded to the second conductive component.

[0109] Item 8: A manufacturing method according to Item 7, wherein, in the above-mentioned joining process, in the radial direction of the above-mentioned through hole, the distance D1 between the above-mentioned through hole and the inner peripheral edge of the above-mentioned ultrasonic joining portion is made smaller than the distance D2 between the outer peripheral edge of the above-mentioned ultrasonic joining portion and the outer peripheral edge of the above-mentioned thin-walled portion (D1<D2).

[0110] Item 9: A manufacturing method according to any one of Items 6 to Item 8, wherein the above-mentioned current collecting component has a hole portion, and the above-mentioned manufacturing method further includes: an insertion step of inserting a portion of the above-mentioned second conductive component of the above-mentioned terminal into the above-mentioned hole portion of the above-mentioned current collecting component; and a caulking step of caulking a portion of the above-mentioned second conductive component of the above-mentioned terminal onto the above-mentioned current collecting component after the above-mentioned insertion step.

[0111] Item 10: A manufacturing method according to Item 9, wherein the second conductive component has a hollow cylindrical portion, and in the caulking step, the cylindrical portion is caulked to the current collecting component, 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 where the ultrasonic bonding portion is formed is taken as a second region, in a direction perpendicular to a surface of the battery case on which the terminal is mounted, the first region protrudes further away from the second conductive component than the second region.

[0112] Item 11: A manufacturing method according to Item 9 or Item 10, wherein, in the above-mentioned caulking step, a portion of the above-mentioned second conductive component is deformed by inserting a supporting fixture into the above-mentioned through hole of the above-mentioned first conductive component so as to be in abutment with the above-mentioned second conductive component and using a stamping fixture to stamp the above-mentioned second conductive component.

[0113] Description of reference numerals:

[0114] 10…electrode body; 14…negative electrode current collecting component (current collecting component); 20…battery case; 24…cover body; 40…negative electrode terminal (terminal); 40c…caulking portion; 41…first conductive component; 41d…lower surface (first surface); 41h…through hole; 41r…first recessed portion; 41t…thin-walled portion; 42…second conductive component; 42f…flange portion; 42n…constricted portion (portion arranged in the recessed portion); 42p…cylindrical portion; 43…fastening portion; 45, 145…ultrasonic bonding portion; 100…electricity storage device.

Claims

1. A method for manufacturing a terminal for an electric storage device, the terminal for an electric storage device comprising: A first conductive member is made of a first metal and has a recessed portion on a first surface and a through hole provided in the recessed portion; a second conductive member, made of a second metal different from the first metal, and having a portion disposed in the recess; an ultrasonic bonding portion for ultrasonically bonding the first conductive member and the second conductive member around the through hole; as well as a fastening portion for mechanically fastening the first conductive member and the second conductive member at an outer peripheral side of the ultrasonic bonding portion, The method for manufacturing the terminal for the power storage device comprises: a disposing step of disposing a portion of the second conductive member in the recessed portion of the first conductive member; and A bonding step of ultrasonically bonding the periphery of the through hole of the first conductive member to the second conductive member after the arranging step.

2. The method for manufacturing a terminal for an electric storage device according to claim 1, wherein: A thin-walled portion is provided around the through hole of the first conductive member, The thickness of the thin-walled portion is thinner than the thickness of a portion on the outer peripheral side of the thin-walled portion. In the bonding step, the thin-walled portion and the second conductive member are ultrasonically bonded to each other.

3. The method for manufacturing a terminal for an electric storage device according to claim 2, wherein: In the joining step, in the radial direction of the through hole, a distance D1 between the through hole and the inner periphery of the ultrasonic joining portion is smaller than a distance D2 between the outer periphery of the ultrasonic joining portion and the outer periphery of the thin-walled portion, ie, D1<D2.

4. The method for manufacturing a terminal for an electric storage device according to claim 2 or 3, characterized in that: In the joining step, ultrasonic joining is performed such that a ratio W1 / W2 of a width W1 of the ultrasonic joining portion to a width W2 of the thin-walled portion in a radial direction of the through hole is equal to or greater than 0.

5.

5. The method for manufacturing a terminal for an electric storage device according to any one of claims 1 to 3, characterized in that: The ultrasonic bonding portion is composed of a plurality of parts, and the plurality of parts are respectively arranged at separate positions.

6. A method for manufacturing an electric storage device, the electric storage device comprising: an electrode body having a first electrode and a second electrode; a battery case accommodating the electrode body; a terminal mounted on the battery case; and a current collecting member electrically connecting the first electrode and the terminal inside the battery case, characterized in that: The terminal has: A first conductive member is made of a first metal and has a recessed portion on a first surface and a through hole provided in the recessed portion; a second conductive member, made of a second metal different from the first metal, and having a portion disposed in the recess; an ultrasonic bonding portion for ultrasonically bonding the first conductive member and the second conductive member around the through hole; a fastening portion for mechanically fastening the first conductive member and the second conductive member at an outer peripheral side of the ultrasonic bonding portion, The manufacturing of the terminal includes: a disposing step of disposing a portion of the second conductive member in the recessed portion of the first conductive member; and A bonding step of ultrasonically bonding the periphery of the through hole of the first conductive member to the second conductive member after the arranging step.

7. The method for manufacturing an electric storage device according to claim 6, wherein: A thin-walled portion is provided around the through hole of the first conductive member, The thickness of the thin-walled portion is thinner than the thickness of a portion on the outer peripheral side of the thin-walled portion. In the bonding step, the thin-walled portion and the second conductive member are ultrasonically bonded to each other.

8. The method for manufacturing an electric storage device according to claim 7, wherein: In the joining step, in the radial direction of the through hole, a distance D1 between the through hole and the inner periphery of the ultrasonic joining portion is smaller than a distance D2 between the outer periphery of the ultrasonic joining portion and the outer periphery of the thin-walled portion, ie, D1<D2.

9. The method for manufacturing an electric storage device according to any one of claims 6 to 8, characterized in that: The current collecting member has a hole portion, The method for manufacturing the power storage device further 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 of the terminal onto the current collecting member after the inserting step.

10. The method for manufacturing an electric storage device according to claim 9, wherein: The second conductive member has a hollow cylindrical portion. In the caulking step, the cylindrical portion is caulked to the current collecting member. When the area of ​​the first conductive component that overlaps with the cylindrical portion in the direction in which the cylindrical portion extends is taken as the first area, and the area where the ultrasonic bonding portion is formed is taken as the second area, in a direction perpendicular to the surface of the battery case on which the terminal is mounted, the first area protrudes further away from the second conductive component than the second area.

11. The method for manufacturing an electric storage device according to claim 9, wherein: In the caulking step, a support jig is inserted into the through hole of the first conductive member so as to be in contact with the second conductive member, and the second conductive member is pressed by a pressing jig, thereby partially deforming the second conductive member.

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