Terminal and battery including terminal

Abstract

To provide a terminal and a battery including the terminal in which conductive members are connected with high strength and are stably connected electrically regardless of the difference in the metal materials, and in which the strength reliability and the electrical conductivity reliability are improved.SOLUTION: A terminal (negative electrode terminal 40) has a plate-shaped first conductive member 41, a second conductive member 42 electrically connected to the first conductive member 41, a fastening portion 43 mechanically fixing the first conductive member 41 and the second conductive member 42 together, and a plating layer 45 interposed between the first conductive member 41 and the second conductive member 42.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to terminals and batteries including the terminals. [Background technology]

[0002] Generally, a battery such as a lithium ion secondary battery comprises an electrode assembly having electrodes and a storage container for housing the electrode assembly. In this type of battery, the electrodes and the battery case are electrically connected to each other. A terminal in which a terminal connected to a battery is pulled out to the outside of a battery case is known. Patent Document 1 is an example of a technology related to such a terminal.

[0003] Patent Document 1 discloses a terminal including a plate-shaped first conductive member, a second conductive member electrically connected to the first conductive member, a fastening portion that mechanically fixes the first conductive member and a flange portion of the second conductive member, and a metal joint portion that metal-joins the first conductive member and the flange portion of the second conductive member at a position away from the fastening portion, as well as a secondary battery including the terminal and a method for manufacturing the terminal and the secondary battery. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-49729 A Summary of the Invention [Problem to be solved by the invention]

[0005] The technique described in Patent Document 1 improves the electrical connection reliability of terminals by metallically joining conductive members of a first conductive member and a second conductive member at a position away from the fastening portion. However, in the technique described in Patent Document 1, when metallically joining conductive members made of different metal materials, cracks may occur at the metallic joining interface due to the difference in metal materials, so there is a problem that the strength reliability and electrical connection reliability of the terminals may decrease. A decrease in the strength reliability and electrical connection reliability of the terminals may lead to a decrease in the quality of the battery including the terminals.

[0006] The present disclosure has been made to solve such problems, and an object thereof is to provide a terminal and a battery including the terminal in which conductive members are connected to each other with high strength and stably conductively connected regardless of the difference in each metal material, improving the strength reliability and electrical connection reliability.

Means for Solving the Problems

[0007] A terminal according to an embodiment includes a plate-shaped first conductive member, a second conductive member electrically connected to the first conductive member, a fastening portion that mechanically fixes the first conductive member and the second conductive member, and a plating layer interposed between the first conductive member and the second conductive member.

[0008] A battery according to an embodiment includes a terminal having a plate-shaped first conductive member, a second conductive member electrically connected to the first conductive member, a fastening portion that mechanically fixes the first conductive member and the second conductive member, and a plating layer interposed between the first conductive member and the second conductive member.

Effects of the Invention

[0009] According to the present disclosure, it is possible to provide a terminal and a battery including the terminal in which conductive members are connected to each other with high strength and stably conductively connected regardless of the difference in each metal material, improving the strength reliability and electrical connection reliability.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0011] Embodiment 1 Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In addition, matters other than those specifically mentioned in this specification and necessary for the implementation of the present disclosure (for example, general configurations and manufacturing processes of batteries that do not characterize the present disclosure) can be grasped as design matters of those skilled in the art based on the prior art in the relevant field. The present disclosure can be implemented based on the content disclosed in this specification and common general knowledge in the relevant field.

[0012] In this specification, the term "battery" refers to all power storage devices capable of extracting electrical energy, and is a concept including primary batteries and secondary batteries. In addition, in this specification, the term "secondary battery" refers to all power storage devices capable of repeated charge and discharge, and is a concept including so-called storage batteries (chemical batteries) such as lithium ion secondary batteries and nickel metal hydride batteries, and capacitors (physical batteries) such as electric double layer capacitors.

[0013] <Battery 100> FIG. 1 is a perspective view schematically showing the battery according to Embodiment 1. In the following description, the reference signs L, R, U, and D in the drawings represent left, right, up, and down, respectively, and the reference signs X, Y, and Z in the drawings represent the long side direction of the battery 100, the short side direction orthogonal to the long side direction, and the vertical direction, respectively. However, these are merely directions for convenience of explanation and do not limit the installation form of the battery 100 in any way.

[0014] As shown in FIG. 1, the battery 100 has a battery case 20. In the present embodiment, the battery 100 is a lithium ion secondary battery. An electrode body and an electrolyte (not shown) are accommodated in the battery case 20.

[0015] The battery case 20 is a housing that accommodates the electrode body. Here, the battery case 20 is formed in a flat and bottomed rectangular parallelepiped shape (rectangular shape). However, the shape of the battery case 20 is not limited to a rectangular shape and may be any shape such as a cylinder. The material of the battery case 20 can be adopted without particular limitation as long as it can be used for a lithium ion secondary battery. The battery case 20 is composed of, for example, a lightweight and highly thermally conductive metal material such as aluminum, an aluminum alloy, or stainless steel.

[0016] The battery case 20 has a case body 22 having an opening and a lid body (sealing plate) 24 that closes the opening. The battery case 20 is integrated by joining (for example, welding) the lid body 24 to the periphery of the opening of the case body 22. The battery case 20 is hermetically sealed.

[0017] The outer shape of the case body 22 is a bottomed square tube shape here. The lid body 24 is attached to the case body 22 so as to close the opening of the case body 22. The lid body 24 is substantially rectangular here. In the present specification, the term "substantially rectangular shape" includes, in addition to a perfect rectangular shape (rectangular shape), for example, a shape in which the corners connecting the long side and the short side of the rectangular shape are R-shaped, or a shape having a notch at the corner.

[0018] The electrode body is disposed inside the battery case 20. The electrode body has a pair of electrodes. One of the pair of electrodes is the positive electrode and the other is the negative electrode. The electrode body is, for example, a flat wound electrode body formed by laminating a strip-shaped positive electrode and a strip-shaped negative electrode in an insulated state via a strip-shaped separator and winding them around a winding axis. However, the electrode body may be a laminated electrode body formed by stacking a rectangular (typically rectangular) positive electrode and a rectangular (typically rectangular) negative electrode in an insulated state. The materials and members constituting the electrode body can be adopted without particular limitation as long as they can be used in a lithium-ion secondary battery.

[0019] The electrodes typically have a current collector and a mixture layer fixed on the current collector and containing an active material. The positive electrode has a positive current collector and a positive mixture layer fixed on the positive current collector. The positive current collector is made of a conductive metal such as aluminum or stainless steel, for example. The positive mixture layer contains a positive active material (such as a lithium transition metal composite oxide), for example. The negative electrode has a negative current collector and a negative mixture layer fixed on the negative current collector. The negative current collector is made of a conductive metal such as copper or stainless steel, for example. The negative mixture layer contains a negative active material (such as a carbon material like graphite), for example.

[0020] The electrolyte can be adopted without particular limitation as long as it can be used in a lithium-ion secondary battery. The electrolyte is, for example, a non-aqueous liquid electrolyte (non-aqueous electrolyte solution) containing a non-aqueous solvent and a supporting salt. The non-aqueous solvent contains carbonates such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate, for example. The supporting salt is a fluorine-containing lithium salt such as LiPF6, for example. However, the electrolyte may be solid (solid electrolyte) and integrated with the electrode body.

[0021] Furthermore, the battery 100 has a pair of terminals. One of the pair of terminals is the positive electrode terminal 30, and the other is the negative electrode terminal 40. The positive electrode terminal 30 and the negative electrode terminal 40 protrude outside the battery case 20. Here, the positive electrode terminal 30 and the negative electrode terminal 40 protrude from the same surface (specifically, the lid body 24) of the battery case 20, respectively. However, the positive electrode terminal 30 and the negative electrode terminal 40 may protrude from different surfaces of the battery case 20, respectively. The positive electrode terminal 30 and the negative electrode terminal 40 are arranged at both end portions in the long side direction X of the lid body 24. At least one of the positive electrode terminal 30 and the negative electrode terminal 40 is an example of the terminal disclosed herein.

[0022] The terminal is electrically connected to the electrode inside the battery case 20. The positive electrode terminal 30 is electrically connected to the positive electrode of the electrode body inside the battery case 20. The negative electrode terminal 40 is electrically connected to the negative electrode of the electrode body inside the battery case 20. The positive electrode terminal 30 and the negative electrode terminal 40 are respectively attached to the lid body 24. The positive electrode terminal 30 and the negative electrode terminal 40 are insulated from the lid body 24 via a gasket 50 and an insulator 60 described later, respectively.

[0023] FIG. 2 is a partially enlarged longitudinal sectional view schematically showing the vicinity of the negative electrode terminal included in the battery shown in FIG. 1. Hereinafter, the terminal structure on the side of the negative electrode terminal 40 will be described in detail as an example, but the terminal structure on the side of the positive electrode terminal 30 may be the same. In that case, in the following description, the term "negative electrode" can be appropriately replaced with "positive electrode".

[0024] As shown in FIG. 2, a terminal lead-out hole 24h penetrating in the vertical direction Z is formed in the lid body 24. In plan view, the terminal lead-out hole 24h is, for example, annular (for example, circular). The terminal lead-out hole 24h has an inner diameter large enough to allow the shaft column portion 42s of the negative electrode terminal 40 before caulking, which will be described later, to pass through. The terminal lead-out hole 24h is formed smaller than the flange portion 42f of the negative electrode terminal 40, which will be described later.

[0025] The negative electrode lead member 14 is attached to an exposed portion of the negative electrode current collector of the electrode body where the negative electrode composite layer is not formed, and constitutes a conduction path for electrically connecting the negative electrode and the negative electrode terminal 40. The negative electrode lead member 14 has a flat plate-like portion 14f that extends horizontally along the inner surface of the lid body 24. A through hole 14h is formed in the flat plate-like portion 14f at a position corresponding to the terminal lead-out hole 24h. The through hole 14h has an inner diameter large enough to allow the shaft column portion 42s of the negative electrode terminal 40 before caulking, which will be described later, to pass through. The negative electrode lead member 14 is fixed to the lid body 24 in a state of being insulated via the insulator 60 by caulking.

[0026] The gasket 50 is an insulating member disposed between the upper surface (outer surface) of the lid body 24 and the negative electrode terminal 40. Here, the gasket 50 insulates the lid body 24 and the negative electrode terminal 40 and has a function of closing the terminal lead-out hole 24h. The gasket 50 is made of a resin material having electrical insulation properties and capable of elastic deformation, such as a fluorinated resin such as perfluoroalkoxy fluororesin (PFA), polyphenylene sulfide resin (PPS), aliphatic polyamide, or the like.

[0027] The gasket 50 has a cylindrical portion 51 and a base portion 52. The cylindrical portion 51 is a part that prevents direct contact between the lid body 24 and the shaft column portion 42s of the negative electrode terminal 40. The cylindrical portion 51 has a hollow cylindrical shape. The cylindrical portion 51 has a through hole 51h that penetrates in the vertical direction Z. The through hole 51h is formed so that the shaft column portion 42s of the negative electrode terminal 40 before caulking can pass through. The cylindrical portion 51 is inserted into the terminal lead-out hole 24h of the lid body 24. The base portion 52 is a part that prevents direct contact between the lid body 24 and the flange portion 42f of the negative electrode terminal 40, which will be described later. The base portion 52 is connected to the upper end of the cylindrical portion 51. The base portion 52 extends horizontally from the upper end of the cylindrical portion 51. The base portion 52 is formed, for example, in an annular shape so as to surround the terminal lead-out hole 24h of the lid body 24. The base portion 52 extends along the upper surface of the lid body 24. The base portion 52 is sandwiched between the lower surface 42d of the flange portion 42f of the negative electrode terminal 40 and the upper surface of the lid body 24, and is compressed in the vertical direction Z by caulking.

[0028] The insulator 60 is an insulating member disposed between the lower surface (inner surface) of the lid body 24 and the negative electrode lead member 14. The insulator 60 has a function of insulating the lid body 24 and the negative electrode lead member 14. The insulator 60 has a flat plate-like portion that spreads horizontally along the inner surface of the lid body 24. A through hole 60h is formed in this flat plate-like portion at a position corresponding to the terminal lead-out hole 24h. The through hole 60h has an inner diameter large enough to allow the shaft column portion 42s of the negative electrode terminal 40 to pass through. The insulator 60 has resistance to the electrolyte used and electrical insulation properties, and is made of a resin material that can be elastically deformed, such as a fluorinated resin such as perfluoroalkoxy fluororesin (PFA), or polyphenylene sulfide resin (PPS). The flat plate-like portion of the insulator 60 is sandwiched between the lower surface of the lid body 24 and the upper surface of the negative electrode lead member 14, and is compressed in the vertical direction Z by caulking.

[0029] <Negative electrode terminal 40> The negative electrode terminal 40 extends from the inside to the outside of the battery case 20 through the terminal lead-out hole 24h. The negative electrode terminal 40 is composed of two types of conductive members, that is, a first conductive member 41 and a second conductive member 42, which are integrated by a fastening portion 43 via a plating layer 45. As shown in FIG. 2, the negative electrode terminal 40 is caulked to the peripheral portion surrounding the terminal lead-out hole 24h of the lid body 24 in a state insulated from the lid body 24 by caulking. A stud portion 40c is formed at the lower end portion of the negative electrode terminal 40. The negative electrode terminal 40 is fixed to the lid body 24 by caulking and is electrically connected to the negative electrode lead member 14.

[0030] FIG. 3 is a partially enlarged longitudinal sectional view schematically showing the negative electrode terminal according to Embodiment 1. FIG. 3 is a longitudinal sectional view schematically showing a part of the negative electrode terminal 40 before being attached to the lid body 24 (that is, before caulking). As shown in FIG. 3, the negative electrode terminal 40 includes a first conductive member 41, a second conductive member 42, a fastening portion 43, and a plating layer 45. The first conductive member 41 and the second conductive member 42 are integrated via the fastening portion 43. Also, at least a part of the first conductive member 41 and the second conductive member 42 are in contact with each other via the plating layer 45 and are electrically connected to each other.

[0031] The first conductive member 41 is a member disposed outside the battery case 20. The first conductive member 41 is made of a conductive metal such as aluminum, an aluminum alloy, nickel, or stainless steel, for example. The first conductive member 41 is plate-shaped. Here, the first conductive member 41 is flat plate-shaped. The first conductive member 41 has a lower surface 41d and an upper surface 41u. The lower surface 41d is the surface on the side facing the battery case 20 (specifically, the lid body 24) and on the side of the second conductive member 42. The upper surface 41u is the surface on the side away from the battery case 20. Here, the first conductive member 41 is substantially rectangular. The first conductive member 41 is a part divided into two in the long side direction X, and has a connection portion 41a electrically connected to the second conductive member 42, and an extension portion 41b extending from the connection portion 41a to one side (the left side in FIG. 3) in the long side direction X.

[0032] The connecting portion 41a has a thin-walled portion 41t formed to be thinner than the extending portion 41b, a through hole 41h penetrating in the vertical direction Z, and a recess 41r recessed from the lower surface 41d of the first conductive member 41. A plating layer 45 is formed on at least a part of the thin-walled portion 41t. The thin-walled portion 41t is formed in an annular shape (for example, a circular ring shape) in plan view. The through hole 41h is formed in an annular shape (for example, a circular ring shape) in plan view. On the upper surface 41u of the first conductive member 41, the second conductive member 42 (specifically, a flange portion 42f described later) is exposed from the through hole 41h. The through hole 41h is provided at the center of the thin-walled portion 41t. The through hole 41h is provided on the inner peripheral side of the fastening portion 43. The through hole 41h can function as a positioning hole for positioning the second conductive member 42 when assembling the first conductive member 41 and the second conductive member 42. The recess 41r is provided on the outer peripheral side of the thin-walled portion 41t. The recess 41r is formed in an annular shape (for example, a circular ring shape) in plan view. The recess 41r is formed in a tapered shape that reduces in diameter toward the lower surface 41d of the first conductive member 41 (in other words, as it approaches the second conductive member 42). A constricted portion 42n of the second conductive member 42 described later is inserted into the recess 41r.

[0033] The extending portion 41b is a portion where a bus bar, which is a conductive member, is attached when, for example, a plurality of batteries 100 are electrically connected to each other to produce a battery pack. By having the extending portion 41b, a sufficient ground contact area with the bus bar can be ensured, and the electrical connection reliability of the battery pack can be improved. By having the extending portion 41b, the first conductive member 41 is shifted to the right in the long side direction X from the center position of the second conductive member 42 (specifically, the center position of the flange portion 42f described later).

[0034] The second conductive member 42 is a member that extends from the inside to the outside of the battery case 20. The second conductive member 42 is made of a conductive metal such as copper, a copper alloy, nickel, or stainless steel. The material of the second conductive member 42 may be, for example, the same as or different from that of the first conductive member 41 in terms of the main component. Here, the second conductive member 42 is made of a metal with a higher hardness than the first conductive member 41. The second conductive member 42 may have a metal coating portion coated with a metal such as Ni on a part or all of its surface. Thereby, the resistance to the electrolyte can be increased and the corrosion resistance can be improved. The second conductive member 42 has an axis C. The second conductive member 42 has a flange portion 42f electrically connected to the first conductive member 41 and a shaft column portion 42s connected to the lower end portion of the flange portion 42f.

[0035] The flange portion 42f has a larger outer shape than the shaft column portion 42s. The flange portion 42f has a larger outer shape than the terminal lead-out hole 24h of the lid body 24. The flange portion 42f is a portion that protrudes from the terminal lead-out hole 24h of the lid body 24 to the outside of the battery case 20. The outer shape of the flange portion 42f is substantially cylindrical here. The axis of the flange portion 42f coincides with the axis C of the second conductive member 42. The flange portion 42f has an upper surface 42u, a lower surface 42d, a side surface (outer peripheral surface) 42o extending upward from the lower surface 42d, and a constricted portion 42n where a part of the side surface 42o is constricted. The upper surface 42u is the surface on the side of the first conductive member 41. The lower surface 42d is the surface on the side away from the first conductive member 41.

[0036] The constriction portion 42n is provided continuously or intermittently on a part of the side surface 42o of the flange portion 42f. The constriction portion 42n is formed in an annular shape (for example, a circular ring shape) in a plan view. When the constriction portion 42n is formed in an annular shape, a high-strength fastening portion 43 can be formed. The constriction portion 42n is formed axially symmetrically with respect to the axis C of the flange portion 42f. The constriction portion 42n is formed in an inverted taper shape that expands in diameter toward the upper surface 42u (in other words, the farther away from the shaft column portion 42s). The constriction portion 42n is inserted into the recess 41r of the first conductive member 41. Here, the constriction portion 42n is fitted into the recess 41r of the first conductive member 41 and is in fit with the recess 41r.

[0037] The shaft column portion 42s extends downward from the lower end portion of the flange portion 42f. Here, the shaft column portion 42s is in a cylindrical shape. The axis of the shaft column portion 42s coincides with the axis C of the flange portion 42f. Before caulking, the lower end portion of the shaft column portion 42s, that is, the end portion on the side opposite to the side where the flange portion 42f is located, is hollow. The shaft column portion 42s is a portion that is inserted into the terminal lead-out hole 24h of the lid body 24 when the negative electrode terminal 40 is attached to the lid body 24. The lower end portion of the shaft column portion 42s is a portion that is expanded by caulking when the negative electrode terminal 40 is attached to the lid body 24 and constitutes the rivet portion 40c. The shaft column portion 42s is electrically connected to the negative electrode lead member 14 inside the battery case 20 by caulking.

[0038] The fastening part 43 is a connecting part that mechanically fixes the first conductive member 41 and the flange part 42f of the second conductive member 42. Here, the fastening part 43 is provided on the outer peripheral side of the flange part 42f rather than the thin-walled part 41t in a plan view. The fastening part 43 is formed in an annular shape (for example, a circular ring shape) in a plan view. Thereby, the strength of the fastening part 43 can be increased, and the conduction reliability of the negative electrode terminal 40 can be further improved. Here, the fastening part 43 is continuously formed. Although not particularly limited, here, the fastening part 43 is provided on the lower surface 41d of the first conductive member 41. Specifically, it is configured by fixing (for example, press-fixing) the inner wall of the concave part 41r of the first conductive member 41 with the constricted part 42n of the second conductive member 42. Thereby, the strength of the fastening part 43 can be improved.

[0039] The forming method of the fastening part 43 is not particularly limited as long as it is a mechanical joining by mechanical energy, and may be, for example, press-fitting, shrink-fitting, caulking, riveting, folding, bolt joining, etc. In some preferred embodiments, the fastening part 43 is a fitting part in which the concave part 41r of the first conductive member 41 and the constricted part 42n of the second conductive member 42 are fitted. Thereby, for example, even if the first conductive member 41 and the second conductive member 42 are made of different metal materials (dissimilar metal materials), the first conductive member 41 and the second conductive member 42 can be preferably fixed. The fastening part 43 may be, for example, a press-fitting part in which the constricted part 42n of the second conductive member 42 is press-fitted into the concave part 41r of the first conductive member 41.

[0040] In this embodiment, the negative electrode terminal 40 is composed of the first conductive member 41 and the second conductive member 42 made of different metal materials (dissimilar metal materials). For example, the first conductive member 41 is composed of a metal material mainly containing aluminum (Al), and the second conductive member 42 is composed of a metal material mainly containing copper (Cu).

[0041] The plating layer 45 is interposed between the first conductive member 41 and the second conductive member 42. The plating layer 45 electrically connects the first conductive member 41 and the second conductive member 42. Here, the plating layer 45 is provided so as to cover the inner peripheral portion of the thin-walled portion 41t.

[0042] In the negative electrode terminal 40, the inner peripheral portion of the thin-walled portion 41t of the first conductive member 41 and the peripheral edge portion of the second conductive member 42 are overlapped with the plating layer 45 interposed therebetween, and the first conductive member 41 and the second conductive member 42 are fastened through the plating layer 45.

[0043] For the plating layer 45, a metal material that can be used for plating treatment such as electrolytic plating can be used without particular limitation. Examples of such metal materials include Ag, Au, Zn, Ni, Cu, Pt, and alloys containing these metal elements. The plating layer 45 formed of these metal materials is preferable because it has high strength and excellent conductivity. Among these metal materials, the plating layer 45 composed of a ZnNi alloy is preferable because it not only has high strength and excellent conductivity but also has high corrosion resistance. The plating layer 45 can be formed on the inner peripheral portion of the thin-walled portion 41t, for example, by performing electrolytic plating on the first conductive member 41 before assembly.

[0044] By interposing the plating layer 45 with excellent conductivity between the first conductive member 41 and the second conductive member 42, the first conductive member 41 and the second conductive member 42 can be stably electrically connected regardless of the difference in their respective metal materials, and a negative electrode terminal 40 with improved electrical connection reliability can be obtained. Here, the plating layer 45 is formed on the inner peripheral portion of the thin-walled portion 41t, which is the peripheral edge portion surrounding the through hole 41h of the first conductive member 41. Thereby, the formation range of the plating layer 45 can be minimized, and the cost for forming the plating layer 45 can be reduced.

[0045] The plating layer 45 is formed continuously or intermittently. The plating layer 45 is formed axially symmetrically with respect to the axis C of the flange portion 42f. The plating layer 45 is formed in an annular shape (for example, a circular ring shape) in a plan view. Thereby, the conduction reliability of the negative electrode terminal 40 can be improved.

[0046] As described above, by having the fastening portion 43, the negative electrode terminal 40 enables the first conductive member 41 and the second conductive member 42 to be connected with high strength. Further, by having the fastening portion 43, even if vibration, impact, etc. are applied from the outside, it becomes difficult for the negative electrode terminal 40 to be deformed, and it becomes easier to maintain the state where the first conductive member 41 and the second conductive member 42 are in close contact. That is, it becomes difficult for the space between the first conductive member 41 and the second conductive member 42 to be separated. Therefore, the conduction connection between the first conductive member 41 and the second conductive member 42 can be stably maintained, and the conduction reliability of the negative electrode terminal 40 can be improved.

[0047] And, by having the plating layer 45, the first conductive member 41 and the second conductive member 42 made of different metal materials are less likely to corrode (galvanic corrosion) due to the aging deterioration of the battery 100, etc., so that it is suppressed that a gap is generated between the first conductive member 41 and the second conductive member 42 due to corrosion. Therefore, compared with the case of having only the fastening portion 43, the grounding area between the first conductive member 41 and the second conductive member 42 is ensured, and the conduction connection between the first conductive member 41 and the second conductive member 42 can be maintained more stably. Therefore, the conduction reliability of the negative electrode terminal 40 can be improved. Further, by having the plating layer 45, the negative electrode terminal 40 can prevent cracks in the metal bonding interface that may occur when the first conductive member 41 and the second conductive member 42 made of different metal materials are metal-bonded by laser welding, ultrasonic bonding, resistance bonding, etc., and can suppress a decrease in the strength reliability and conduction reliability of the negative electrode terminal 40 due to cracks in the metal bonding interface.

[0048] Therefore, according to the present embodiment, regardless of the difference in each metal material, the conductive members are connected to each other with high strength and stably conductively connected, and it is possible to provide the negative electrode terminal 40 with improved strength reliability and conduction reliability.

[0049] As described above, some embodiments of the present disclosure have been described, but the above embodiments are merely examples. The present disclosure can be implemented in various other forms. The present disclosure can be implemented based on the content disclosed in this specification and the common general knowledge in the art. The technology described in the claims includes various modifications and changes of the above-exemplified embodiments. For example, it is also possible to replace a part of the above-described embodiments with other modified forms, and it is also possible to add other modified forms to the above-described embodiments. Further, if its technical features are not described as essential, it can be appropriately deleted.

[0050] For example, in the above-described embodiment, in the second conductive member 42, the constricted portion 42n was provided in a part of the side surface 42o of the flange portion 42f. However, it is not limited to this. The constricted portion 42n may be provided, for example, in the entire side surface 42o of the flange portion 42f.

[0051] For example, in the above-described embodiment, the first conductive member 41 had the thin portion 41t, and the plating layer 45 was formed on the inner peripheral portion of the thin portion 41t. However, it is not limited to this. The plating layer 45 may be interposed between the first conductive member 41 and the second conductive member 42. For example, it may be formed outside the inner peripheral portion of the thin portion 41t of the first conductive member 41. Further, the plating layer 45 may be formed, for example, on a part or all of the portion of the lower surface 41d of the first conductive member 41 that does not have the through hole 41h and corresponds to the second conductive member 42, or on a part or all of the portion of the upper surface 42u of the second conductive member 42 that corresponds to the first conductive member 41.

[0052] For example, in the above-described embodiment, the fastening portion 43 was a fitting portion (e.g., a press-fit portion). However, it is not limited to this. The fastening portion 43 may be, for example, a caulking portion. Therefore, FIG. 4 is a partially enlarged longitudinal sectional view schematically showing a negative electrode terminal according to a modified example. The negative electrode terminal 140 shown in FIG. 4 may be the same as the above-described negative electrode terminal 40 except having a first conductive member 141, a second conductive member 142, and a fastening portion 143.

[0053] The first conductive member 141 may be the same as the above-described first conductive member 41 except not having the concave portion 41r and having a plurality of leg portions 141p. The leg portions 141p protrude downward (the same side as the shaft column portion 42s) from the lower surface 141d of the first conductive member 141 and are formed so as to be able to insert through the through hole 142h of the second conductive member 142 in the state before caulking. The plurality of leg portions 141p are formed axially symmetrically with respect to the axis C of the flange portion 142f described later. The number of the leg portions 141p is, for example, six.

[0054] The second conductive member 142 may be the same as the above-described second conductive member 42 except having a flange portion 142f having a through hole 142h at a position corresponding to each of the plurality of leg portions 141p instead of the constricted portion 42n. The plurality of leg portions 141p respectively insert through the corresponding through holes 142h. The tip portions of the leg portions 141p are caulked. A caulking portion 141c is formed at the peripheral portion surrounding the through hole 142h of the second conductive member 142. Here, the fastening portion 143 is the caulking portion 141c. In a plan view, the caulking portion 141c is formed in an intermittent annular shape (e.g., a circular ring shape) with respect to the axis C of the flange portion 42f. Thereby, the strength of the fastening portion 143 can be improved, and the workability when forming the fastening portion 143 can be improved.

Description of Reference Numerals

[0055] 14 Negative electrode lead member 14f Flat plate-like portion 14h Through hole 20 Battery case 22 Case body 24 Lid body 24h Terminal lead-out hole 30 Positive electrode terminal 40 Negative electrode terminal 40c Stud portion 41 First conductive member 41a Connection portion 41b Extension portion 41d Bottom surface 41h Through hole 41r Recess 41t Thin portion 41u Top surface 42 Second conductive member 42d Bottom surface 42f Flange portion 42n Constriction portion 42o Side surface 42s Shaft column portion 42u Top surface 43 Fastening portion 45 Plating layer 50 Gasket 51 Cylindrical portion 51h Through hole 52 Base portion 60 Insulator 60h Through hole 100 Battery 140 Negative electrode terminal 141 First conductive member 141c Caulked portion 141d Bottom surface 141p Leg portion 142 Second conductive member 142f Flange portion 142h Through hole 143 Fastening portion C Axis center

Claims

1. A plate-shaped first conductive member, a second conductive member electrically connected to the first conductive member, a fastening portion that mechanically fixes the first conductive member and the second conductive member, a plating layer interposed between the first conductive member and the second conductive member, and a terminal having the same.

2. The second conductive member has a through hole, the first conductive member has a leg portion in which a tip portion inserted into the through hole of the second conductive member is caulked, The terminal according to claim 1, wherein the fastening portion is configured by inserting the leg portion of the first conductive member into the through hole of the second conductive member.

3. The first conductive member has a through hole, The terminal according to claim 1, wherein the plating layer is formed on a peripheral portion surrounding the through hole of the first conductive member.

4. The terminal according to claim 1, wherein the plating layer is made of a ZnNi alloy.

5. A plate-shaped first conductive member, a second conductive member electrically connected to the first conductive member, a fastening portion that mechanically fixes the first conductive member and the second conductive member, a plating layer interposed between the first conductive member and the second conductive member, and a battery including a terminal having the same.

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