Terminal for secondary battery and method of manufacturing terminal for secondary battery

Abstract

To provide a terminal for a secondary battery which is improved in adhesiveness between a junction component and a joined member.SOLUTION: A terminal for a secondary battery comprises a metallic junction member 10 and a metallic joined member 11 which is joined with the junction member 10 so as not to be removed. In the junction member 10, there are provided a bag hole part 13 (projecting part 15) and an annular projection 14 which is formed outside of the bag hole part 13 (projecting part 15). The joined member 11 is adhered with the bag hole part 13 (projecting part 15) and the annular projection 14 with no gap. The junction member 10 includes the annular projection 14, such that the junction member 10 and the joined member 11 have high adhesiveness even in an outside portion of the bag hole part 13 (projecting part 15).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a terminal for a secondary battery formed by joining dissimilar metal members together, and to a method for manufacturing the same. [Background technology]

[0002] A known secondary battery terminal formed by joining dissimilar metals is shown in Patent Document 1. This secondary battery terminal is formed by pressing a plate-shaped member made of aluminum and a rod-shaped member made of copper together, with the center of the plate-shaped member flowing into a recess formed in the rod-shaped member, and is used as a negative electrode terminal for lithium-ion batteries. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7389766 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the terminals of conventional secondary batteries tend to have poor adhesion at the contact points between flat surfaces away from the recesses, resulting in poor electrical conductivity and poor strength.

[0005] The present invention has been made in view of the above problems, and has as its object to provide a terminal for a secondary battery having excellent adhesion and a method for joining the terminal for the secondary battery. [Means for solving the problem]

[0006] The present invention was created in consideration of the above-mentioned problems, and is a terminal for a secondary battery having a metal joining member and a metal joined member that is non-detachably joined to the joining member, wherein the joining member is provided with a blind hole portion and an annular protrusion formed outside the opening of the blind hole portion, and the joined member is filled into the blind hole portion and is in close contact with the annular protrusion without any gaps. Alternatively, it is preferable that the terminal of a secondary battery has a metal joining member and a metal joined member that is non-detachably joined to the joining member, wherein the joining member is provided with a protrusion and an annular convex portion formed outside the base end of the protrusion, and the joined member is in close contact with the protrusion and the annular convex portion without any gaps. It is preferable that the annular projection is inclined radially outward or radially inward from the base end to the tip end. It is also preferable that the annular protrusion has a barrel-shaped cross section in the circumferential direction. Furthermore, it is preferable that the upper surface of the annular convex portion is formed with irregularities. Alternatively, the terminal of a secondary battery is made of a metal joining member having a head and a shaft, and a metal joined member to which the head of the joining member is joined so that it cannot be removed, and the head seating surface of the joining member is provided with an annular convex portion extending toward the shaft, and the joined member covers the entire head of the joining member together with the annular convex portion, and is in close contact with the head.

[0007] A second object of the present invention is a method for manufacturing a terminal for the above-mentioned secondary battery, which includes a step of overlaying the joinable member on a metal joining member and a metal joinable member overlaid on the joining member, and a pressurizing step of applying pressure to the joinable member and the joining member to plastically deform the joinable member so that it flows along the joining member, thereby closely adhering the joinable member and the joining member, wherein the joining member has an annular convex portion on the surface on which the joinable member is overlaid, and during the pressurizing step, the annular convex portion is gradually deformed into a tapered shape that tapers radially outward or radially inward as it moves from the base end side to the tip end side due to the flow of the joinable member. Alternatively, in a method for manufacturing a terminal for a secondary battery, the method includes a step of overlapping the joinable member on the joining member, which includes a metal joining member and a metal joinable member overlapped on the joining member, and a pressurizing step of pressurizing the joinable member and the joining member, thereby plastically deforming the joinable member so that it flows along the joining member, thereby closely adhering the joinable member and the joining member, the joining member being characterized in that an annular protrusion is provided on the surface on which the joinable member is overlapped, and during the pressurizing step, the annular protrusion is deformed so that its circumferential cross section is barrel-shaped. Alternatively, in a method for manufacturing a terminal for a secondary battery, the method includes a step of overlapping the head of a metal joining member having a head and a shaft, and a metal joinable member overlapped on the head of the joining member, and a pressurizing step of pressurizing the joinable member and the joining member, thereby plastically deforming the joinable member so that it flows along the joining member, thereby bringing the joinable member and the head of the joining member into tight contact with each other, the joining member is characterized in that an annular convex portion is provided on the seating surface of the head, and during the pressurizing step, the joinable member is deformed so as to cover the entire head of the joining member, including the annular convex portion. [Effects of the Invention]

[0008] The terminal of the secondary battery manufactured by the present invention has high pull-out strength because the annular protrusions on the joining members catch against the pull-out direction. In addition, the annular protrusions of the joining members are covered by the ends of the joined members, resulting in high adhesion.

[0009] Furthermore, in the manufacturing method of the secondary battery terminal, the annular protrusion formed on the head of the joining part is deformed by the flow of the joined members, so there is no need to form a tapered annular protrusion in advance, which has the advantage that the joining member can be formed relatively easily. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing the shape of a terminal of a secondary battery according to the present invention before joining; [Figure 2]1A and 1B are diagrams showing the shape of terminals of a secondary battery according to the present invention; [Figure 3] 1A to 1C are diagrams showing a method for joining terminals of a secondary battery according to the present invention. [Figure 4] FIG. 4 is a diagram showing a state transitioning from the state of FIG. 3 to the next state. [Figure 5] 1 is a cross-sectional perspective view of a terminal of a secondary battery according to the present invention. [Figure 6] 1 is an enlarged view of a main portion of a terminal of a secondary battery according to the present invention. [Figure 7] 10 is an enlarged view of a main portion showing another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 8] 10 is an enlarged view of a main portion showing another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 9] 10 is an enlarged view of a main portion showing another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 10] 10 is an enlarged view of a main portion showing another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 11] 10 is an enlarged view of a main portion showing another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 12] 10 is an enlarged view of a main portion showing another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 13] 10 is an enlarged view of a main portion showing another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 14] 10 is an enlarged view of a main portion showing another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 15] 10 is an enlarged view of a main portion showing another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 16] 10 is an enlarged view of a main portion showing another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 17] 10 is an enlarged view of a main portion showing another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 18] 10A and 10B are diagrams showing another embodiment of the terminal of the secondary battery according to the present invention. [Figure 19] 10A and 10B are diagrams showing another embodiment of the terminal of the secondary battery according to the present invention. [Figure 20] 10A and 10B are diagrams showing another embodiment of the terminal of the secondary battery according to the present invention. [Figure 21] 10A and 10B are diagrams showing another embodiment of the terminal of the secondary battery according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] A secondary battery terminal and its manufacturing method will be described below with reference to the drawings. Figures 1(a) and 1(b) show the shape of a secondary battery terminal before joining, and the terminal of the secondary battery of the present application is composed of a joining member 10 made of a copper material shown in Figure 1(b) and a joined member 20 made of an aluminum material shown in Figure 1(a). The joining member 10 and the joined member 20 are formed and prepared separately in advance, and are formed, for example, by cold heading or cutting.

[0012] The joining member 10 is composed of a flat head portion 11 and a shaft portion 12 integrally formed therewith. The top surface of the head portion 11 is provided with a blind hole portion 13 with a bottom and an annular protrusion portion 14 located on the outer periphery of the blind hole portion 13.

[0013] The blind hole portion 13 has an inner peripheral wall formed in a reverse tapered shape, and this reverse tapered portion 131 is inclined in a direction in which the blind hole portion 13 widens as it approaches the bottom.

[0014] The annular projection 14 is formed so as to be continuous with the outer peripheral edge of the head 11, and is configured in a uniform shape over the entire circumference.

[0015] The workpiece 20 is cylindrical, and its end 21 is formed to be sufficiently larger than the opening area of ​​the blind hole 13 of the joining member 10 and smaller than the inner wall of the annular protrusion 14.

[0016] By joining the joining member 10 and the member to be joined 20, the terminal of the secondary battery shown in FIG. 2 is manufactured.

[0017] 3 and 4 are diagrams showing a method for joining the joining member 10 and the joined member 20. The receiving mold 100 has a stepped insertion hole 101, and is configured so that the head 11 of the joining member 10 is suspended from the stepped portion and the shaft 12 of the joining member 10 is loosely fitted into the insertion hole 101, thereby holding the joining member 10 in the insertion hole 101.

[0018] Next, as shown in FIG. 3, the end 21 of the workpiece 20 is placed so as to block the blind hole 13 of the workpiece 10. Then, the punch pin 200 is advanced downward to compress the workpiece 20 in the axial direction from the other end 22 side of the workpiece 20, causing the end 21 of the workpiece 20 to flow due to plastic deformation. As a result, the workpiece 20 is filled into the blind hole 13 of the head 11 of the workpiece 10, as shown in FIG. 4. At the same time, the workpiece 20 is flattened by the compressive force. At this time, the workpiece 20 moves radially outward, overcoming the annular protrusion 14, which is inclined so as to widen radially outward as it approaches the workpiece 20, as shown in FIGS. 2 and 6.

[0019] Next, the joining member 10 and the member to be joined 20 are joined by compressing them until the end 21 of the member to be joined 20 is completely filled in the blind hole portion 13 of the joining member 10 and the member to be joined 20 becomes flat.

[0020] When the joining is completed, the terminal of the secondary battery is ejected from the receiving mold 100 by moving the knockout pin 102 arranged below the insertion hole 101 of the receiving mold 100 upward.

[0021] The terminal of a secondary battery manufactured by the above joining method has high pull-out strength because the reverse tapered portion 131 of the joining member 10 catches the center against the pull-out direction as shown in Figure 5. Also, the end 21 of the joined member 20 is completely filled into the blind hole 13 of the joining member 10, resulting in high adhesion. Furthermore, the joined member 20 is in close contact with the inclined annular protrusion 14 of the joining member 10, enveloping it, improving adhesion between the joined member 20 and the joining member 10 even at positions away from the blind hole 13. Moreover, because the annular protrusion 14 is deformed by the flow of the joined member 20, this method has the advantage of allowing the joining member 10 to be manufactured more inexpensively than a method in which the annular protrusion 14 is deformed into a desired shape in advance.

[0022] A secondary battery terminal having such an effect is suitable for use as, for example, the negative terminal of a lithium ion battery (not shown), where the shaft portion 12 of the joining member 10 is connected to a current collector plate (not shown) inside the lithium ion battery, and the joined member 20 is exposed to the outside of the lithium ion battery and connected to a bus bar (not shown). The terminal of the secondary battery manufactured according to the present invention is joined with high adhesion and has excellent electrical conductivity, so when used as the negative terminal of a lithium ion battery, the electrical resistance can be kept low.

[0023] Other embodiments of the annular projection 14, which is a main part of the present invention, will be described below with reference to FIGS. The embodiments shown in Figures 7 and 8 differ from the first embodiment in that the annular protrusion 14 is inclined toward the center of the joining member 10 as it approaches the workpiece 20. As shown in Figure 8, there is no problem if the outer peripheral edge of the head 11 of the joining member 10 also inclines as the annular protrusion 14 inclines. The embodiment shown in Figure 9 differs from the first embodiment in that the annular protrusion 14 is barrel-shaped in cross section, with the central portion bulging in the axial direction. As in these embodiments, the annular protrusion 14 is inclined or deformed into a barrel shape, and the workpiece 20 embraces the annular protrusion 14, thereby providing a high retention effect.

[0024] 10 and 11, an uneven portion may be formed on the upper surface of the annular convex portion 14, and the workpieces 20 may be configured to enclose the uneven portion. Forming the uneven portion in this manner increases the contact area between the joining member 10 and the workpieces 20, thereby further improving adhesion. Furthermore, as in the embodiments shown in FIGS. 12 and 13, there is no problem even if the uneven portion is inclined radially outward or toward the center during joining. Furthermore, the uneven portion may be wedge-shaped, as in the embodiments shown in FIGS. 14 to 17.

[0025] Furthermore, as in the embodiment shown in Figure 18, the annular convex portion 14 may be formed between the blind hole portion 13 and the outer peripheral edge of the head 11 of the joining member 10. Also, as in the embodiment shown in Figure 19, there is no problem if an inverted tapered protrusion 15 protruding toward the joined member 20 is formed on the upper surface of the joining member 10, and the joined member 20, which has been plastically deformed, envelops the protrusion 15 during joining. Furthermore, as in the embodiment shown in Figure 20, the joined member 20 may be configured to cover not only the annular convex portion 14 but also the outer peripheral edge of the head 11 of the joining member 10. Furthermore, as in the embodiment shown in Figure 21, the annular convex portion 14 may be formed on the seating surface of the head 11 of the joining member 10, and the joined member 20 may cover the entire head 11 of the joining member 10.

[0026] The present invention is not limited to the above-described embodiment and various modifications are possible without departing from the spirit and scope of the present invention. For example, in the above-described embodiment, the annular protrusion 14 is uniformly configured in the circumferential direction. However, there is no problem if the annular protrusion 14 has a non-uniform structure in the circumferential direction, such as a knurled shape with unevenness formed on the inner and outer circumferences, or a structure in which the radial thickness or axial dimension gradually changes in the circumferential direction. Furthermore, the shapes of the head 11 and the shank 12 can be changed by changing the shape of the receiving die 100. Therefore, when forming the outer periphery of the head 11 into a tapered shape as in the embodiment shown in FIG. 8, the pressing process shown in FIGS. 3 and 4 is performed using a receiving die 100 whose portion that abuts against the outer periphery of the head 11 is tapered. Furthermore, the blind hole 13 and the protrusion 15 are not limited to the inverse tapered shape described above. There is no problem if the blind hole 13 and the protrusion 15 have other shapes, such as a barrel shape or a double cone shape with an expanded diameter at the axial center.

[0027] Furthermore, when the annular protrusion 14 is tilted radially outward as in the first embodiment shown in FIG. 6, the workpieces 20 are configured to have a smaller diameter than the annular protrusion 14 so that the workpieces 20 flow from the inside to the outside of the annular protrusion 14 during welding. On the other hand, when the annular protrusion 14 is tilted radially inward as in the embodiment shown in FIG. 7, etc., the workpieces 20 are molded while being constrained by a mold at the outer periphery so that the workpieces 20 flow from the outside to the inside of the annular protrusion 14 during welding. At this time, the inside of the annular protrusion 14 is set so that the workpieces 20 do not fill until the annular protrusion 14 is tilted inward. Furthermore, there is no problem if the underside of the workpieces 20 is provided with irregularities as needed to satisfy the above conditions. [Explanation of symbols]

[0028] 10... Joint material 11 … Head 12 ... Shaft 13 … Blind hole part 131... Tapered section 14... Annular convex part 20... Joint material 100... Receiving type 101... Insertion hole 102... Knockout pin 200... Punch pin

Claims

1. A metal joining member; A terminal of a secondary battery having the joining member and a metal joined member that are non-detachably joined to the joining member, the joining member is provided with a blind hole portion and an annular protrusion portion formed outside an opening of the blind hole portion, The secondary battery terminal is characterized in that the member to be joined is filled in the blind hole portion and is in close contact with the annular protrusion portion without any gaps.

2. A metal joining member; A terminal of a secondary battery having the joining member and a metal joined member that are non-detachably joined to the joining member, the joining member is provided with a protrusion and an annular convex portion formed outside a base end of the protrusion, The terminal for a secondary battery is characterized in that the member to be joined is in close contact with the protrusion and the annular convex portion without any gaps.

3. 3. The terminal for a secondary battery according to claim 1, wherein the annular protrusion is inclined radially outward or radially inward from the base end to the tip end.

4. 3. The terminal for a secondary battery according to claim 1, wherein the annular protrusion has a barrel-shaped circumferential cross section.

5. 3. The terminal for a secondary battery according to claim 1, wherein the annular protrusion has an upper surface formed with irregularities.

6. a metal joining member having a head and a shaft; A terminal of a secondary battery with a metal member to which the head of the joining member is joined so as not to be detachable, The head seating surface of the joining member is provided with an annular protrusion extending toward the shaft portion, The terminal for a secondary battery, wherein the member to be joined covers the entire head of the joining member together with the annular protrusion and is in close contact with the head.

7. A metal joining member; a metal member to be joined that is placed on the joining member; a step of placing a member to be joined on the joining member; a pressure step of pressurizing the joined members and the joining members to plastically deform the joined members so that the joined members flow along the joining members, thereby closely adhering the joined members to the joining members, The joining member has an annular convex portion on a surface on which the joined members are placed, A method for manufacturing a secondary battery terminal, characterized in that during the pressurizing process, the annular convex portion gradually deforms into a tapered shape extending radially outward or radially inward as it moves from the base end side to the tip end side due to the flow of the joined members.

8. A metal joining member; a metal member to be joined that is placed on the joining member; a step of placing a member to be joined on the joining member; a pressure step of pressurizing the joined members and the joining members to plastically deform the joined members so that the joined members flow along the joining members, thereby closely adhering the joined members to the joining members, The joining member has an annular convex portion on a surface on which the joined members are placed, In the pressurizing step, the annular protrusion is deformed so that its circumferential cross section is barrel-shaped.

9. a metal joining member having a head and a shaft; a metal member to be joined placed on the head of the joining member; a step of overlapping a workpiece on the head of the joining member; a pressure step of pressurizing the joined members and the joining members to plastically deform the joined members so that the joined members flow along the joining members, thereby bringing the joined members and the heads of the joining members into close contact with each other, The joining member has an annular protrusion on the seat surface of the head, In the pressurizing step, the joined members are deformed so as to cover the entire head of the joining member together with the annular protrusion.

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