Terminal for secondary batteries and secondary battery

Abstract

To provide a terminal for secondary batteries where terminal members are firmly connected together, and a secondary battery equipped with the terminal for secondary batteries where the terminal members are firmly connected together.SOLUTION: An anode terminal 7 of a secondary battery 1 includes a covering terminal member 150 that covers a flange part 110 of a basic terminal member 100. In a covering range H in which the outer circumference is covered of an outer circumferential covering part 170 of the covering terminal member 150, the flange part 110 includes a groove 120, a top face-side protrusion 130 located opposite the shank 32 side farther than the groove 120, and a seating face-side protrusion 140 located opposite the shank 32 side farther than the groove 120. Furthermore, a seating face-side outermost circumferential distance D2 from the outermost circumference of the seating face-side protrusion 140 to a center axis 32C of the shank 32 is shorter than a top face-side outermost circumferential distance D1 from the outermost circumference of the seating face-side protrusion 140 to the center axis 32C. The outer circumferential covering part 170 has a projection 173 of a shape corresponding to the groove 120.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The disclosed technology relates to a terminal for a secondary battery comprising a first terminal member having an axis portion and a flange portion provided at the end of the axis portion, and a second terminal member that covers the flange portion, and to a secondary battery comprising the same. [Background technology]

[0002] Conventionally, some secondary battery terminals are configured by combining a plurality of members. For example, Patent Document 1 discloses a secondary battery terminal configured by connecting two terminal members (conductive members) by a fastening structure that mechanically fixes them. Specifically, one of the terminal members has a flange portion provided at the end of the shaft portion that is formed with a constricted shape. The other terminal member is provided so as to cover the flange portion of the one terminal member, and is formed with a shape that fits into the constricted shape of the flange portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-049729 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, depending on the environment in which the secondary battery is used, a force that releases the connection between the connected terminal members may act on the connected terminal members. Specifically, for example, in a secondary battery mounted on a vehicle, a force that moves one of the connected terminal members away from the other terminal member may act on the connected terminal member due to vibrations transmitted to the secondary battery.

[0005] For example, if the connection of the terminal members becomes unstable, the secondary battery may not be able to be charged or discharged properly. For this reason, it is preferable that the structure of the connection points of the terminal members be such that the terminal members can be connected to each other more firmly.

[0006] The present disclosure has been made to solve the problems of the conventional techniques described above. That is, the object of the disclosure is to provide a secondary battery terminal in which terminal members are firmly connected to each other, and a secondary battery including a secondary battery terminal in which terminal members are firmly connected to each other. [Means for solving the problem]

[0007] One aspect of the disclosed technology is a secondary battery terminal comprising a first terminal member having a shaft portion and a flange portion provided at an axial end of the shaft portion, and a second terminal member covering the flange portion, wherein the second terminal member has an outer peripheral covering portion covering an outer periphery of the flange portion, and the flange portion has a groove portion extending in the circumferential direction in a covered area where the outer periphery is covered by the outer peripheral covering portion, so that a first protrusion protruding outer periphery further than a bottom of the groove is provided on the opposite side of the shaft portion from the groove, and a second protrusion protruding outer periphery further than the bottom of the groove is provided on the shaft portion side from the groove, and a second distance from the outermost circumference of the second protrusion to the central axis of the shaft portion is shorter than a first distance from the outermost circumference of the first protrusion to the central axis of the shaft portion, and the outer peripheral covering portion has a convex portion shaped to correspond to the space inside the groove.

[0008] In the secondary battery terminal according to the above embodiment, when a force acts in a direction in which the first terminal member and the second terminal member are separated from each other, the convex portion of the outer circumferential covering portion of the second terminal member is deformed so as to extend toward the shaft portion of the first terminal member, and the terminal members are separated. The convex portion of the outer circumferential covering portion moves due to deformation to a second protrusion covering region, which is a region of the outer circumferential covering portion that covers the second protrusion. In other words, when the first terminal member and the second terminal member are separated, the second protrusion covering region of the outer circumferential covering portion is also deformed. However, a considerable load is required for the convex portion of the outer circumferential covering portion and the second protrusion covering region to deform to a degree that the first terminal member and the second terminal member are separated. This is because the deformation region of the outer circumferential covering portion is large, and the movement distance related to the deformation is also large. Therefore, in the secondary battery terminal according to this embodiment, the terminal members are firmly connected to each other.

[0009] Another aspect of the disclosed technology is a secondary battery including the above-described secondary battery terminal. Thus, the secondary battery according to this aspect has a secondary battery terminal in which the terminal members are firmly connected to each other. Effect of the Invention

[0010] According to the disclosed technique, there is provided a secondary battery terminal in which terminal members are firmly connected to each other, and a secondary battery including a secondary battery terminal in which terminal members are firmly connected to each other. [Brief description of the drawings]

[0011] [Figure 1] 1 is an external perspective view of a secondary battery according to an embodiment; [Diagram 2] FIG. 2 is a cross-sectional view of the secondary battery according to the embodiment at the position of the negative electrode terminal. [Diagram 3] FIG. 2 is a diagram showing a negative electrode terminal according to the embodiment. [Figure 4] 4 is an enlarged cross-sectional view of the vicinity of the outer periphery of the flange portion of the base terminal member of the negative electrode terminal before separation according to the embodiment. FIG. [Diagram 5]4 is an enlarged cross-sectional view of the vicinity of the outer periphery of the flange portion of the base terminal member of the negative electrode terminal after separation according to the embodiment. FIG. [Figure 6] FIG. 13 is a diagram showing a negative electrode terminal according to a reference embodiment. [Figure 7] 10 is an enlarged cross-sectional view of the vicinity of the outer periphery of the flange portion of the base terminal member of the negative electrode terminal according to the reference embodiment before separation. FIG. [Figure 8] 11 is an enlarged cross-sectional view of the vicinity of the outer periphery of the flange portion of the base terminal member of the negative electrode terminal after separation according to the reference embodiment. FIG. [Figure 9] 1 is a graph showing the results of a separation test of negative electrode terminals produced under various conditions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment that embodies the present disclosure will be described in detail with reference to the accompanying drawings. A secondary battery 1 according to this embodiment is, as shown in FIG. 1, generally configured by housing an electrode assembly 3 inside an exterior body 2. The electrode assembly 3 is configured by laminating a positive electrode plate 3A and a negative electrode plate 3B with a separator 3C interposed therebetween. The exterior body 2 is configured by a box body 4 and a lid body 10. In this embodiment, both the box body 4 and the lid body 10 that constitute the exterior body 2 are made of a material having electrical conductivity. Specifically, both the box body 4 and the lid body 10 are made of metal. An electrolyte 5 is housed inside the exterior body 2.

[0013] The secondary battery 1 has an overall rectangular flat-plate shape. A positive electrode terminal 6 and a negative electrode terminal 7 are provided near both ends of the upper lid 10 in the longitudinal direction. Both the positive electrode terminal 6 and the negative electrode terminal 7 are secondary battery terminals used in the secondary battery 1. Both the positive electrode terminal 6 and the negative electrode terminal 7 are attached to the lid 10. Both the positive electrode terminal 6 and the negative electrode terminal 7 are made of a conductive material. The positive electrode terminal 6 and the negative electrode terminal 7 are each electrically connected to the electrode body 3 inside the exterior body 2. Specifically, the positive electrode terminal 6 is connected to the positive electrode plate 3A, and the negative electrode terminal 7 is connected to the negative electrode plate 3B.

[0014] When viewed from the outside of the secondary battery 1, the positive terminal surface 6A of the positive terminal 6 and the negative terminal surface 7A of the negative terminal 7 are visible. The positive terminal surface 6A and the negative terminal surface 7A are surfaces to which other metal members that form a current path for charging and discharging the secondary battery 1 are connected. This allows the secondary battery 1 to be charged or discharged via the positive terminal 6 and the negative terminal 7.

[0015] Fig. 2 is a cross-sectional view at the position of the negative electrode terminal 7 in the secondary battery 1. Fig. 2 is a cross-sectional view in the short direction of the lid 10. As shown in Fig. 2, the negative electrode terminal 7 is composed of two terminal members. Specifically, the negative electrode terminal 7 is composed of a basic terminal member 100 which is a first terminal member, and a covering terminal member 150 which is a second terminal member. In the negative electrode terminal 7 of the embodiment, the covering terminal member 150 is a member which covers the outer part of the exterior body 2 in the basic terminal member 100.

[0016] 2 also shows members constituting the periphery of the negative electrode terminal 7. The secondary battery 1 has a current collecting member 20, a gasket 40, and an insulator 50 around the negative electrode terminal 7. The lid body 10 is a plate-shaped member. The lid body 10 has an outer surface 11 and an inner surface 12 as end faces in the thickness direction. In FIG. 2, the side below the inner surface 12 of the lid body 10 is the inside of the exterior body 2. The lid body 10 has a through hole 13 penetrating in the thickness direction.

[0017] The current collecting member 20 is a member that connects the electrode body 3 and the negative electrode terminal 7 inside the exterior body 2. FIG. 2 shows a terminal connection portion 21 of the current collecting member 20, which is a connection portion to the negative electrode terminal 7. The current collecting member 20 is connected to the negative electrode plate 3B that constitutes the electrode body 3 at a portion different from the terminal connection portion 21. The current collecting member 20 is made of a material having electrical conductivity. Specifically, the material of the current collecting member 20 on the negative electrode side can be, for example, copper.

[0018] The terminal connection portion 21 of the current collecting member 20 has a plate-like shape. The terminal connection portion 21 of the current collecting member 20 has an outer surface 22 and an inner surface 23 as end faces in the thickness direction. The outer surface 22 faces the inner surface 12 of the lid 10. The terminal connection portion 21 of the current collecting member 20 has a through hole 24 penetrating in the thickness direction. The through hole 24 of the current collecting member 20 is provided at a position overlapping with the through hole 13 of the lid 10. In other words, the through hole 24 of the current collecting member 20 is provided coaxially with the through hole 13 of the lid 10.

[0019] The negative electrode terminal 7 has a plate-shaped portion 31, a shaft portion 32, and a crimping portion 33. The plate-shaped portion 31 and the crimping portion 33 are provided on both ends of the shaft portion 32. The shaft portion 32 is passed through both the through hole 13 of the lid 10 and the through hole 24 of the current collecting member 20.

[0020] The disk-shaped portion 31 is located on the outside of the exterior body 2. The disk-shaped portion 31 is connected to the exterior side of the exterior body 2 at the shaft portion 32. The disk-shaped portion 31 has a shape that is wider than the through-hole 13 of the lid 10.

[0021] The crimped portion 33 is located inside the exterior body 2. The crimped portion 33 is connected to the inner side of the exterior body 2 at the shaft portion 32. Furthermore, the crimped portion 33 is located on the inner side of the exterior body 2 relative to the current collecting member 20. The crimped portion 33 has a shape that is wider than the through hole 24 of the current collecting member 20. The crimped portion 33 is formed by passing the shaft portion 32 of the negative electrode terminal 7 through each member from the outer side of the exterior body 2 and then performing a crimping process.

[0022] 2, the crimped portion 33 before crimping is indicated by a two-dot chain line. The negative terminal 7 is in contact with the current collecting member 20 near the crimped portion 33. This electrically connects the negative terminal 7 and the current collecting member 20. Furthermore, the negative terminal 7 is fixed to the secondary battery 1 by sandwiching the lid 10 or the like between the plate-shaped portion 31 and the crimped portion 33.

[0023] Both the base terminal member 100 and the covering terminal member 150 of the negative electrode terminal 7 are made of a material having electrical conductivity. In the embodiment, the base terminal member 100 and the covering terminal member 150 are made of different materials. In the embodiment, the covering terminal member 150 is made of a material having a lower strength than the material of the base terminal member 100. Specifically, for example, the base terminal member 100 can be made of copper, and the covering terminal member 150 can be made of aluminum.

[0024] The basic terminal member 100 has a shaft portion 32 and a crimping portion 33, and is a member that constitutes a part of the plate-shaped portion 31. As shown in Fig. 2, the basic terminal member 100 has a flange portion 110 that constitutes a part of the plate-shaped portion 31. The flange portion 110 is provided at the end of the shaft portion 32 in the axial direction.

[0025] Flange portion 110 has a top surface 111 facing the outside of exterior body 2, a seating surface 112 facing the inside, and an outer peripheral surface 113 located on the outer periphery. Top surface 111 is the surface opposite to shaft portion 32. Seat surface 112 is the surface on the shaft portion 32 side and faces outer surface 11 of lid body 10. Outer peripheral surface 113 is a surface connecting top surface 111 and seating surface 112.

[0026] The covered terminal member 150 is a member constituting a part of the plate-shaped portion 31 of the negative electrode terminal 7. The covered terminal member 150 is provided so as to cover the flange portion 110 of the basic terminal member 100. As a result, the covered terminal member 150 covers the top surface 111 and the outer circumferential surface 113 of the flange portion 110. Note that the seat surface 112 of the flange portion 110 is not covered by the covered terminal member 150.

[0027] The coated terminal member 150 has a top surface covering portion 160 and an outer peripheral covering portion 170. The top surface covering portion 160 is a portion covering the top surface 111 of the flange portion 110. The outer surface 161 of the top surface covering portion 160 is a surface exposed to the outside of the exterior body 2, and is the negative electrode terminal surface 7A of the negative electrode terminal 7. The inner surface 162 of the top surface covering portion 160 faces the top surface 111 of the flange portion 110 and contacts the top surface 111. Therefore, a conductive path is formed through which electricity flows from one of the basic terminal member 100 and the coated terminal member 150 to the other. In order to form the conductive path more reliably, the top surface covering portion 160 of the coated terminal member 150 may be joined to the top surface 111 of the flange portion 110 of the basic terminal member 100 by welding.

[0028] Outer peripheral covering portion 170 is a portion that covers outer peripheral surface 113 of flange portion 110. Outer peripheral surface 171 of outer peripheral covering portion 170 is a surface that is exposed to the outside of exterior body 2. An inner peripheral surface 172 of outer peripheral covering portion 170 faces outer peripheral surface 113 of flange portion 110 and is in contact with the outer peripheral surface 113.

[0029] Both the gasket 40 and the insulator 50 are made of a material that has elasticity and insulating properties, and is resistant to the electrolyte 5. Specifically, perfluoroalkoxy fluororesin (PFA) can be used as the material of the gasket 40. Polyphenylene sulfide (PPS) that does not contain inorganic filler can be used as the material of the insulator 50.

[0030] The gasket 40 is disposed from the outside of the exterior body 2, and is an external seal member that seals the gap between the negative terminal 7 and the lid body 10 while insulating the negative terminal 7 from the lid body 10. The gasket 40 has an external plate-shaped portion 41 and an external tubular portion 42. The gasket 40 is provided with a through hole 43 that forms the inner circumference of the external tubular portion 42. The external plate-shaped portion 41 is sandwiched between the outer surface 11 of the lid body 10 and the plate-shaped portion 31 of the negative terminal 7. As a result, the external plate-shaped portion 41 is in close contact with both the outer surface 11 of the lid body 10 and the plate-shaped portion 31 of the negative terminal 7. The surface of the plate-shaped portion 31 of the negative terminal 7 that is in close contact with the external plate-shaped portion 41 is the seat surface 112 of the flange portion 110 of the basic terminal member 100.

[0031] The outer tubular portion 42 is connected to the inner side of the exterior body 2 in the outer plate-shaped portion 41. The outer tubular portion 42 is located inside the through hole 13 of the lid body 10. The shaft portion 32 of the negative electrode terminal 7 is passed through the inside of the through hole 43 of the gasket 40. The outer tubular portion 42 is sandwiched between the wall surface of the through hole 13 of the lid body 10 and the shaft portion 32 of the negative electrode terminal 7. As a result, the outer tubular portion 42 is in close contact with both the wall surface of the through hole 13 of the lid body 10 and the shaft portion 32 of the negative electrode terminal 7.

[0032] A protrusion 15 is provided on the outer surface 11 of the cover 10 with which the external plate-shaped portion 41 of the gasket 40 is in contact. The side of the external plate-shaped portion 41 opposite to the protrusion 15 is in contact with a seating surface 112 of the flange portion 110 of the basic terminal member 100. The external plate-shaped portion 41 is pressed against the protrusion 15 by the seating surface 112. As a result, the protrusion 15 bites into the external plate-shaped portion 41, and the external plate-shaped portion 41 is deformed according to the shape of the protrusion 15. Since the external plate-shaped portion 41 is sandwiched between the seating surface 112 of the flange portion 110 and the protrusion 15 in this manner, the exterior body 2 is reliably sealed at the position of the negative electrode terminal 7.

[0033] The insulator 50 is disposed inside the exterior body 2, and is a member that insulates the current collecting member 20 from the lid body 10. The insulator 50 is a plate-shaped member. The insulator 50 is provided with a through hole 52. The insulator 50 is sandwiched between the inner surface 12 of the lid body 10 and the terminal connection portion 21 of the current collecting member 20. This allows the insulator 50 to be in close contact with both the inner surface 12 of the lid body 10 and the current collecting member 20. The insulator 50 is also in close contact with the outer tubular portion 42 of the gasket 40 inside the through hole 13 of the lid body 10.

[0034] With this configuration, the secondary battery 1 is appropriately sealed at the position of the negative electrode terminal 7. Also, contact between the lid 10 and the negative electrode terminal 7 and between the lid 10 and the current collecting member 20 are both prevented. Furthermore, the electrolyte 5 is prevented from entering the gap between the gasket 40 and the insulator 50. In other words, electrical conduction between the lid 10 and the negative electrode terminal 7 via the electrolyte 5 is also appropriately prevented.

[0035] 3 is a diagram showing the negative electrode terminal 7 before being attached to the lid 10. Therefore, the crimping portion 33 is shown in its shape before being crimped. The flange portion 110 of the basic terminal member 100 is provided with a groove portion 120 extending in the circumferential direction on its outer periphery. In the embodiment, the groove portion 120 is provided continuously around the outer periphery of the flange portion 110. Moreover, the flange portion 110 in the embodiment has a circular shape when viewed from the axial direction of the shaft portion 32.

[0036] Furthermore, a groove portion 120 is provided on the outer periphery of the flange portion 110, thereby providing two protrusions. That is, the flange portion 110 is provided with a top surface side protrusion 130 which is a first protrusion, and a seat surface side protrusion 140 which is a second protrusion. The top surface side protrusion 130 is located on the opposite side of the groove portion 120 from the shaft portion 32 side. The seat surface side protrusion 140 is located on the shaft portion 32 side from the groove portion 120.

[0037] Both the top surface side protrusion 130 and the seat surface side protrusion 140 protrude further toward the outer periphery of the flange portion 110 than the bottom 121 of the groove portion 120. In other words, the top surface side outermost periphery distance D1, which is the distance from the outermost periphery of the top surface side protrusion 130 to the central axis 32C of the shaft portion 32, is longer than the bottom distance D0, which is the distance from the bottom 121 of the groove portion 120 to the central axis 32C. In addition, the seat surface side outermost periphery distance D2, which is the distance from the outermost periphery of the seat surface side protrusion 140 to the central axis 32C, is also longer than the bottom distance D0.

[0038] 3 shows a covered area H of the outer periphery of the flange portion 110 of the basic terminal member 100 that is covered by the outer periphery covering portion 170 of the covered terminal member 150. The covered area H includes the top surface side protrusion 130, the groove portion 120, and the seat surface side protrusion 140. In the embodiment, almost the entire outer periphery of the flange portion 110 from the top surface 111 to the seat surface 112 is covered by the covered area H.

[0039] As described above, the inner peripheral surface 172 of the outer peripheral covering portion 170 of the covered terminal member 150 is in contact with the outer peripheral surface 113 of the flange portion 110. As a result, the inner peripheral surface 172 of the outer peripheral covering portion 170 has a shape corresponding to the outer peripheral surface 113 of the flange portion 110 on which the groove portion 120, the top surface side protrusion 130, and the seat surface side protrusion 140 are provided. In other words, the outer peripheral covering portion 170 of the covered terminal member 150 has, on the inner peripheral surface 172 side, a convex portion 173 having a shape corresponding to the space inside the groove portion 120 of the basic terminal member 100.

[0040] Furthermore, in the shape of the flange portion 110 in the embodiment, the top surface side protrusion 130 protrudes further toward the outer periphery of the flange portion 110 than the seat surface side protrusion 140. In other words, the seat surface side outermost periphery distance D2 is shorter than the top surface side outermost periphery distance D1.

[0041] For example, in the secondary battery 1, a force may act on the negative electrode terminal 7 such that the base terminal member 100 and the covering terminal member 150 are separated. In order to electrically connect the secondary battery 1 to other secondary batteries, etc., a bus bar or the like is attached to the negative electrode terminal 7. The fixed location of the bus bar is the negative electrode terminal surface 7A of the negative electrode terminal 7, which is the covering terminal member 150 constituting the negative electrode terminal 7. Meanwhile, the base terminal member 100 of the negative electrode terminal 7 sandwiches the cover body 10 of the secondary battery 1 in the thickness direction between the seat surface 112 of the flange portion 110 and the crimping portion 33, and is fixed to the secondary battery 1. Depending on the environment in which the secondary battery 1 is used, a force may act on the bus bar in a direction away from the secondary battery 1. In such a case, a force may act on the connection portion between the base terminal member 100 fixed to the secondary battery 1 and the covering terminal member 150 to which the bus bar is connected, causing them to separate. In such a case, if the connection between the base terminal member 100 and the covering terminal member 150 becomes unstable, the secondary battery 1 may not be able to be charged or discharged properly.

[0042] However, the negative electrode terminal 7 of the embodiment has the above-mentioned configuration, so that the base terminal member 100 and the covering terminal member 150 are not easily separated. That is, the base terminal member 100 and the covering terminal member 150 are firmly connected. Therefore, the secondary battery 1 including the negative electrode terminal 7 can maintain its charge / discharge performance for a long period of time.

[0043] Next, the strong connection between the base terminal member 100 and the covered terminal member 150 in the negative electrode terminal 7 of the embodiment will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is an enlarged cross-sectional view of the negative electrode terminal 7 near the outer periphery of the flange portion 110 of the base terminal member 100.

[0044] FIG. 4 shows a deformation region X of the outer circumferential covering portion 170 of the covered terminal member 150, which is a region that is mainly deformed when the basic terminal member 100 and the covered terminal member 150 are separated. The deformation region X is a region surrounded by the inner circumferential surface 172 of the outer circumferential covering portion 170 and a virtual line X1. The virtual line X1 is a virtual line extending a first contact position 175 on the inner circumferential surface 172 of the outer circumferential covering portion 170 in the axial direction of the shaft portion 32. The first contact position 175 is a position of the outer circumferential covering portion 170 that contacts the outer circumferential surface 113 at the outermost periphery of the top surface side protrusion 130 of the flange portion 110. FIG. 4 also shows a seat side protrusion covering region XA of the deformation region X that covers the outer periphery of the seat side protrusion 140.

[0045] 4 also shows a second contact position 176 of the outer circumferential covering portion 170. The second contact position 176 is a position of the outer circumferential covering portion 170 that is in contact with the end of the groove portion 120 of the flange portion 110 on the seat surface side protrusion portion 140 side. The first contact position 175 and the second contact position 176 are also positions that indicate the base of the convex portion 173. For this reason, the deformation region X shown in FIG. 4 is a region that includes the entire convex portion 173.

[0046] 5 shows the state after the basic terminal member 100 and the covered terminal member 150 have been separated. Specifically, it shows the state when the covered terminal member 150 is moved in the axial direction of the shaft portion 32 (i.e., upward in the figure) from the state in FIG. 4 until it is separated from the basic terminal member 100. It can be seen that the covered terminal member 150 is separated from the basic terminal member 100 by deforming the deformation region X. The deformation region X after separation has a shape that is extended downward in FIG. 5 as a whole, compared to the shape before separation indicated by the two-dot chain line.

[0047] In order for the basic terminal member 100 and the covered terminal member 150 to be separated, the deformation region X of the covered terminal member 150 needs to be deformed so as to be wider than the outermost periphery of the top surface side protrusion 130 of the flange portion 110 of the basic terminal member 100. Naturally, the convex portion 173 that was contained inside the groove portion 120 is significantly deformed so as to extend downward. Also, as can be seen from FIG. 5, the deformation of the covered terminal member 150 when the negative electrode terminal 7 according to the embodiment is separated extends not only to the convex portion 173 but also to its periphery.

[0048] Specifically, after the negative terminal 7 is separated, the second contact position 176 of the outer periphery covering portion 170 is pushed outward beyond the outermost periphery of the top surface side protrusion 130 while moving downward. That is, the seat surface side protrusion covering region XA of the outer periphery covering portion 170, which covered the outer periphery of the seat surface side protrusion 140 of the flange portion 110 before separation, has moved significantly. As shown in FIG. 4, the seat surface side protrusion covering region XA is originally present at the location to which the convex portion 173, which deforms to extend downward during separation, moves. Therefore, the seat surface side protrusion covering region XA prevents the deformation of the convex portion 173 during separation. Furthermore, the imaginary line X1, which extended from the first contact position 175 of the outer periphery covering portion 170 in the axial direction of the shaft portion 32 before separation, moves away from the flange portion 110 as shown in the lower part after separation.

[0049] Here, a negative electrode terminal of a reference embodiment different from the negative electrode terminal 7 of the embodiment will be described. FIG. 6 shows a negative electrode terminal 8 of the reference embodiment. The negative electrode terminal 8 of the reference embodiment is composed of a basic terminal member 200 and a covered terminal member 250. The basic terminal member 200 has a crimped portion 33 and a flange portion 210 at both ends of a shaft portion 32. The crimped portion 33 shows a shape before crimping. The covered terminal member 250 is provided so as to cover the flange portion 210 of the basic terminal member 200. That is, the covered terminal member 250 has a top surface covering portion 260 and an outer periphery covering portion 270.

[0050] The flange portion 210 of the basic terminal member 200 is provided with a groove portion 220 extending in the circumferential direction on its outer periphery. The flange portion 210 of the basic terminal member 200 also has the groove portion 220 provided continuously around the outer periphery of the flange portion 210. The groove portion 220 is provided on the outer periphery of the flange portion 210, thereby providing a top surface side protrusion portion 230 and a seat surface side protrusion portion 240. The top surface side protrusion portion 230 is located on the opposite side of the groove portion 220 to the shaft portion 32 side. The seat surface side protrusion portion 240 is located on the shaft portion 32 side of the groove portion 220.

[0051] Both the top surface side protrusion 230 and the seat surface side protrusion 240 protrude further toward the outer periphery of the flange portion 210 than the bottom 221 of the groove portion 220. In other words, the top surface side outermost periphery distance D1, which is the distance from the outermost periphery of the top surface side protrusion 230 to the central axis 32C, is longer than the bottom distance D0, which is the distance from the bottom 221 of the groove portion 220 to the central axis 32C. In addition, the seat surface side outermost periphery distance D2, which is the distance from the outermost periphery of the seat surface side protrusion 240 to the central axis 32C, is also longer than the bottom distance D0.

[0052] In the flange portion 210 of the reference embodiment, only a part of the top surface 211 side of the outer circumferential surface 213 that connects from the top surface 211 to the seat surface 212 is covered with the covering range H. That is, in the negative electrode terminal 8, the covering range H that is covered by the outer circumferential covering portion 270 of the covered terminal member 250 of the outer periphery of the flange portion 210 of the basic terminal member 200 includes the top surface side protrusion 230 and the groove portion 220. On the other hand, the covering range H of the negative electrode terminal 8 does not include the seat surface side protrusion 240. Therefore, the outer periphery of the seat surface side protrusion 240 is exposed. And, the outer circumferential covering portion 270 of the covered terminal member 250 has a convex portion 273 on the inner circumferential surface 272 side that has a shape corresponding to the space inside the groove portion 220 of the basic terminal member 200.

[0053] Furthermore, the flange portion 210 of the negative electrode terminal 8 is shaped such that the seat side protrusion 240 protrudes further toward the outer periphery of the flange portion 210 than the top side protrusion 230. That is, the seat side outermost periphery distance D2 is longer than the top side outermost periphery distance D1.

[0054] Next, separation of the negative terminal 8 of the reference embodiment will be described with reference to Figs. 7 and 8. Fig. 7 is an enlarged cross-sectional view of the negative terminal 8 near the outer periphery of the flange portion 210 of the basic terminal member 200. Fig. 7 shows a deformation region Y of the outer periphery covering portion 270 of the covered terminal member 250, which is a region that is mainly deformed when the basic terminal member 200 and the covered terminal member 250 are separated. The deformation region Y is a region surrounded by the inner periphery 272 of the outer periphery covering portion 270 and a virtual line X1. The virtual line X1 is a virtual line connecting the third contact position 275 and the fourth contact position 276.

[0055] The third contact position 275 is a position of the outer periphery covering portion 270 that is in contact with the outer periphery 213 at the outermost periphery of the top surface side protrusion 230 of the flange portion 210. The fourth contact position 276 is a position of the outer periphery covering portion 270 that is in contact with the end of the groove portion 220 of the flange portion 210 on the seat surface side protrusion 240 side. The third contact position 275 and the fourth contact position 276 are also positions that indicate the base of the convex portion 273. For this reason, the deformation region Y shown in FIG. 7 is a region that indicates the convex portion 273.

[0056] Fig. 8 shows the state after the basic terminal member 200 and the covered terminal member 250 are separated. Specifically, it shows the state when the covered terminal member 250 is moved upward from the state in Fig. 7 until it is separated from the basic terminal member 200. It can be seen that the covered terminal member 250 is separated from the basic terminal member 200 by deforming the deformation region Y. The deformation region Y after separation has a shape that extends downward in Fig. 8 compared to the shape before separation indicated by the two-dot chain line.

[0057] In order for the basic terminal member 200 and the covered terminal member 250 to separate, the deformation region Y of the covered terminal member 250 needs to be deformed so as to be wider than the outermost periphery of the top surface side protrusion 230 of the flange portion 210 of the basic terminal member 200. However, as described above, in the negative electrode terminal 8 according to the reference embodiment, the deformation region Y of the covered terminal member 250 is only the protrusion 273.

[0058] Specifically, even after the negative terminal 8 is separated, the fourth contact position 276 of the outer circumferential covering part 270 does not move from before the separation. Therefore, the imaginary line Y1 does not move either before or after the separation. This is because, in the negative terminal 8 of the reference embodiment, when the convex part 173, which is the deformation region Y, deforms so as to extend downward, there is no part that hinders the deformation.

[0059] From the above, in the negative electrode terminal 7 of the embodiment in which the seat side protrusion covering region XA exists, the region that deforms when the two terminal members are separated is larger than in the negative electrode terminal 8 of the reference embodiment. Furthermore, in the negative electrode terminal 7 of the embodiment, the moving distance related to the deformation when the two terminal members are separated is also larger than in the negative electrode terminal 8 of the reference embodiment. As a result, the negative electrode terminal 7 of the embodiment is configured such that the two terminal members are less likely to separate than the negative electrode terminal 8 of the reference embodiment. That is, in the negative electrode terminal 7 of the embodiment, the base terminal member 100 and the covering terminal member 150 are firmly connected.

[0060] Next, a separation test using a negative electrode terminal will be described. In the separation test, a tensile load was applied to a negative electrode terminal composed of a base terminal member and a covering terminal member as described in the above embodiment and reference form in the axial direction of the shaft portion in a direction in which these two terminal members separate. The tensile load applied to the negative electrode terminal was gradually increased until the base terminal member and the covering terminal member separated, and the tensile load at which they separated was recorded as the separation load.

[0061] The results of the separation test are shown in Figure 9. The negative electrode terminals used in the separation test were of the type with a covering on the protruding portion on the seat side, the results of which are plotted as circles in Figure 9, and of the type without a covering on the protruding portion on the seat side, the results of which are plotted as diamonds in Figure 9.

[0062] In the case of a negative electrode terminal with a covering of the seat side protrusion, the covering terminal member covers the seat side protrusion of the flange of the basic terminal member. Specifically, in the case of a negative electrode terminal with a covering of the seat side protrusion, the covering terminal member covers the top side protrusion, the groove, and the seat side protrusion of the outer periphery of the flange of the basic terminal member. The negative electrode terminal 7 of the embodiment belongs to the negative electrode terminal with a covering of the seat side protrusion.

[0063] In the negative electrode terminal of the type without covering the protrusion on the seat side, the covering terminal member covers up to the groove of the flange of the basic terminal member. Specifically, in the negative electrode terminal of the type without covering the protrusion on the seat side, the covering terminal member covers both the top protrusion and the groove of the outer periphery of the flange of the basic terminal member, but does not cover the protrusion on the seat side. Negative electrode terminal 8 of the reference embodiment belongs to the negative electrode terminal of the type without covering the protrusion on the seat side.

[0064] Furthermore, in the separation test, negative terminals with and without a covering on the protruding portion on the seat side were used, each with different ratios of the top surface side outermost distance D1 to the seat side outermost distance D2. The horizontal axis in Fig. 9 shows D2 / D1, which is the ratio of the top surface side outermost distance D1 to the seat side outermost distance D2. The vertical axis in Fig. 9 shows the separation load, which is the tensile load when the negative terminals were separated in the separation test.

[0065] As shown in FIG. 9, for the negative electrode terminal of the type without a covering of the protruding portion on the seat side, which is shown by a diamond plot, the separation load is almost constant regardless of the value of D2 / D1. In the negative electrode terminal of the type without a covering of the protruding portion on the seat side, there is no part that prevents the deformation of the convex portion of the covering terminal member that moves from the inside to the outside of the groove of the flange portion of the basic terminal member during separation. In other words, in the negative electrode terminal of the type without a covering of the protruding portion on the seat side, there is no part corresponding to the covering region XA of the protruding portion on the seat side described in the negative electrode terminal 7 of the embodiment, and only the convex portion of the covering terminal member is deformed, causing the negative electrode terminal to separate. For this reason, in the negative electrode terminal of the type without a covering of the protruding portion on the seat side, in which the covering terminal member does not have a part corresponding to the covering region XA of the protruding portion on the seat side, the separation load tends to be low regardless of the value of D2 / D1.

[0066] In contrast, for negative electrode terminals with a covered protrusion on the seat side, shown by a circle plot, the separation load differs at the boundary where the value of D2 / D1 is 1. Specifically, negative electrode terminals with a covered protrusion on the seat side, where the value of D2 / D1 is 1 or greater, exhibited the same separation load as negative electrode terminals with no covering on the seat side protrusion.

[0067] On the other hand, negative electrode terminals with a covered protrusion on the seat side, where the value of D2 / D1 is less than 1, tend to have a larger separation load than negative electrode terminals without a covered protrusion on the seat side. Also, negative electrode terminals with a covered protrusion on the seat side, where the value of D2 / D1 is less than 1, tend to have a larger separation load as the value of D2 / D1 becomes smaller.

[0068] Even in the case of negative electrode terminals with a covered protrusion on the seat side, if the value of D2 / D1 is 1 or more, only the protrusion of the covered terminal member can be deformed and separated. This is because the part of the covered terminal member corresponding to the covered area XA of the seat side protrusion is located outside the outermost periphery of the top side protrusion of the flange part of the basic terminal member. For this reason, even in the case of negative electrode terminals with a covered protrusion on the seat side, if the value of D2 / D1 is 1 or more, there is no part that prevents the deformation of the protrusion of the covered terminal member moving from the inside to the outside of the groove of the flange part of the basic terminal member, and it is considered that the separation load was low.

[0069] Among the negative electrode terminals with a covered seat side protrusion, those with a D2 / D1 value smaller than 1 are the negative electrode terminals 7 of the embodiment. For this reason, among the negative electrode terminals with a covered seat side protrusion, those with a D2 / D1 value smaller than 1 have the covered seat side protrusion area XA in the deformation area X of the covered terminal member. For this reason, among the negative electrode terminals with a covered seat side protrusion, those with a D2 / D1 value smaller than 1 have the covered seat side protrusion area XA preventing deformation of the convex portion of the covered terminal member during separation. Therefore, negative electrode terminals with a covered seat side protrusion and a D2 / D1 value smaller than 1 have a large separation load.

[0070] Furthermore, in the case of a negative electrode terminal with a covering on the seat side protrusion, the smaller the value of D2 / D1 is in the range of less than 1, the larger the covering area XA of the seat side protrusion tends to be. Therefore, in the case of a negative electrode terminal with a covering on the seat side protrusion, the smaller the value of D2 / D1 is in the range of less than 1, the larger the separation load is considered to be. In the case of a negative electrode terminal with a covering on the seat side protrusion, the value of D2 / D1 is preferably 0.8 or less. In a negative electrode terminal with a covering on the seat side protrusion, in which the value of D2 / D1 is 0.8 or less, the separation load is sufficiently larger than that of a negative electrode terminal without a covering on the seat side protrusion and a negative electrode terminal with a covering on the seat side protrusion, in which the value of D2 / D1 is 1 or more. This is because the connection between the base terminal member and the covering terminal member can be reliably and firmly established.

[0071] The smaller the value of D2 / D1, the smaller the bearing surface of the basic terminal member of the negative electrode terminal tends to be. However, as described above, in the negative electrode terminal 7 of the embodiment, the bearing surface 112 of the flange portion 110 of the basic terminal member 100 is, for example, a surface required to seal the exterior body 2. Furthermore, the bearing surface 112 of the basic terminal member 100 is, for example, a surface required to fix the negative electrode terminal 7 to the lid body 10. For this reason, it is not preferable that the bearing surface 112 of the basic terminal member 100 is too small, and a certain degree of size is required. Therefore, in a negative electrode terminal with a bearing surface side protrusion coating, the value of D2 / D1 is preferably 0.2 or more. This is because the size of the bearing surface 112 of the flange portion 110 can be sufficiently secured in a negative electrode terminal with a bearing surface side protrusion coating type in which the value of D2 / D1 is 0.2 or more.

[0072] As described above in detail, the negative electrode terminal 7 of the secondary battery 1 according to this embodiment includes a basic terminal member 100 which is a first terminal member, and a covered terminal member 150 which is a second terminal member. The basic terminal member 100 has a shaft portion 32 and a flange portion 110 provided at an end portion in the axial direction of the shaft portion 32. The covered terminal member 150 has an outer peripheral covering portion 170 which covers the outer periphery of the flange portion 110. In the covering range H in which the outer periphery is covered by the outer peripheral covering portion 170, the flange portion 110 is provided with a groove portion 120 extending in the circumferential direction, and thus two protrusions are provided which protrude outward from the bottom portion 121 of the groove portion 120. That is, the flange portion 110 is provided with a top surface side protrusion 130 which is a first protrusion, and a seat surface side protrusion 140 which is a second protrusion. The top surface side protrusion 130 is located on the opposite side of the shaft portion 32 from the groove portion 120. The seat side protrusion 140 is located closer to the shaft portion 32 than the groove portion 120. Furthermore, the flange portion 110 has a top surface side outermost periphery distance D1, which is a first distance from the outermost periphery of the seat side protrusion 140 to the central axis 32C of the shaft portion 32, and a seat side outermost periphery distance D2, which is a second distance from the outermost periphery of the seat side protrusion 140 to the central axis 32C, which is shorter than the top surface side outermost periphery distance D1. Moreover, the outer periphery covering portion 170 has a convex portion 173 having a shape corresponding to the space inside the groove portion 120.

[0073] In such a negative electrode terminal 7, when a force acts in a direction in which the basic terminal member 100 and the covered terminal member 150 are separated from each other, the convex portion 173 of the outer circumferential covering portion 170 of the covered terminal member 150 is deformed so as to extend toward the shaft portion 32 side of the basic terminal member 100, and the basic terminal member 100 is separated from the covered terminal member 150. The convex portion 173 of the outer circumferential covering portion 170 moves due to deformation to a seat surface side protrusion covering region XA, which is a region of the outer circumferential covering portion 170 that covers the seat surface side protrusion 140. In other words, when the basic terminal member 100 and the covered terminal member 150 are separated, the seat surface side protrusion covering region XA of the outer circumferential covering portion 170 is also deformed. However, a considerable load is required for the convex portion 173 of the outer circumferential covering portion 170 and the seat surface side protrusion covering region XA to deform to the extent that the basic terminal member 100 and the covered terminal member 150 are separated. This is because the deformation region X of the outer circumferential covering part 170 is large, and further, the movement distance associated with the deformation is also large. Therefore, in the negative electrode terminal 7 which is a terminal for the secondary battery 1 according to this embodiment, the terminal members are firmly connected to each other. Therefore, a secondary battery terminal in which the terminal members are firmly connected to each other and a secondary battery using the same are realized.

[0074] The above-described embodiments are merely examples and do not limit the present disclosure in any way. Therefore, the present disclosure can be modified and changed in various ways without departing from the spirit and scope of the present disclosure.

[0075] For example, in the above embodiment, the configuration of the negative electrode terminal 7 side has been described in detail. However, as long as it is a terminal for a secondary battery, it can be applied regardless of whether it is a positive electrode or a negative electrode. That is, the configuration of the positive electrode terminal 6 side can be the same as that of the negative electrode terminal 7 described above. In this case, the positive electrode terminal 6 may be made of a material different from that of the negative electrode terminal 7. Note that the positive electrode terminal 6 may be made of one terminal member instead of two terminal members as in the negative electrode terminal 7. In addition, the wall surface of the exterior body 2 on which the positive electrode terminal 6 and the negative electrode terminal 7 are provided is not limited to the lid body 10, and may be the box body 4.

[0076] In the above embodiment, the flange portion 110 of the basic terminal member 100 has a circular shape when viewed from the axial direction of the shaft portion 32. However, the shape of the flange portion 110 when viewed from the axial direction of the shaft portion 32 is not limited to a circular shape. Specifically, the flange portion 110 may have a rectangular shape, for example. In addition, the flange portion 110 of the basic terminal member 100 has a groove portion 120 that is provided continuously around the outer periphery of the flange portion 110. That is, the flange portion 110 has a top surface side protrusion 130, a groove portion 120, and a seat surface side protrusion 140 that are provided continuously around the outer periphery of the flange portion 110. However, the top surface side protrusion 130, the groove portion 120, and the seat surface side protrusion 140 may be provided only on a part of the outer periphery of the flange portion 110. Specifically, the top surface side protrusion 130, the groove portion 120, and the seat surface side protrusion 140 may be provided in a range of the outer periphery of the flange portion 110 that faces each other. Furthermore, the cross-sectional shapes of the top surface side protrusion 130, the groove portion 120, and the seat surface side protrusion 140 are not limited to the shapes described in the above embodiment, and may adopt shapes different from the shapes described in the above embodiment.

[0077] In the above embodiment, the battery is described as being flat and rectangular in shape. However, the battery shape is not particularly limited to the battery to which the above embodiment is applied. Furthermore, the battery type (nickel-metal hydride battery, lithium-ion battery, etc.) is not particularly limited to the battery to which the above embodiment is applied.

[0078] The above-disclosed technology also includes the following means 1 to 3. [Means 1] 2. The battery of claim 1, The flange portion has a ratio of the second distance to the first distance of 0.8 or less.

[0079] [Means 2] A battery according to claim 1 or claim 1, The flange portion has a ratio of the second distance to the first distance of 0.2 or more.

[0080] [Means 3] A secondary battery comprising the terminal for a secondary battery according to any one of claims 1, means 1 and means 2. [Explanation of symbols]

[0081] 1: Secondary battery 7: Negative terminal (secondary battery terminal) 32: Shaft 32C: Central axis 100: Basic terminal member (first terminal member) 110: Flange part 113: Outer surface 120: Groove 121: Bottom 130: Top surface side protrusion (first protrusion) 140: Seat side protrusion (second protrusion) 150: Covered terminal member (second terminal member) 170: Outer covering part 173: Convex D0: Bottom distance D1: Top side outermost circumference distance D2: Outermost circumference distance on the seat side H: Coverage range

Claims

1. a first terminal member having a shaft portion and a flange portion provided at an end portion in an axial direction of the shaft portion, and a second terminal member covering the flange portion; the second terminal member has an outer periphery covering portion that covers an outer periphery of the flange portion, In the covering range where the outer periphery of the flange portion is covered by the outer periphery covering portion, a groove portion extending in a circumferential direction is provided, and a first protruding portion is provided on the opposite side of the groove portion from the shaft portion and protruding radially outward from a bottom of the groove portion; and a second protruding portion is provided on the shaft portion side of the groove portion and protruding radially outward from the bottom of the groove portion; a second distance from an outermost periphery of the second protrusion to a central axis of the shaft portion is shorter than a first distance from an outermost periphery of the first protrusion to a central axis of the shaft portion; The outer covering portion has a protrusion having a shape corresponding to the space inside the groove portion.

2. The secondary battery terminal according to claim 1, The flange portion has a ratio of the second distance to the first distance of 0.8 or less.

3. The secondary battery terminal according to claim 1, The flange portion has a ratio of the second distance to the first distance of 0.2 or more.

4. A secondary battery comprising the secondary battery terminal according to any one of claims 1 to 3.

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