Terminal of secondary battery

Abstract

To provide a terminal of a secondary battery excellent in adhesion between a joining component and a member to be joined.SOLUTION: At least one of the joining member (10) and the joined member (20) includes a joint portion (13) having a blind hole shape, the other of the joining member (10) and the joined member (20) includes a convex portion with which the joint portion (13) is filled, and a center of the joint portion (13) is shifted from a center of a joint interface between the joining member (10) and the joined member (20). Since the center of the joint portion 13 is shifted from the center of the joint interface as described above, a rotation prevention effect is obtained, and an effect that the joined member 20 is less likely to be detached from the joined member 10 is obtained.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. [Background technology]

[0002] A terminal for a secondary battery formed by joining dissimilar metals is known from Patent Document 1. This secondary battery terminal is formed by pressing a rod-shaped joining member made of copper and a plate-shaped joined member made of aluminum together, so that the center of the joined member flows into a joining recess formed in the joining member. This type of secondary battery terminal is used as a negative electrode terminal for a lithium-ion battery. [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, in conventional secondary battery terminals, the joining recess is located on the central axis, and the joining interface is uniform in the circumferential direction, which causes problems such as the joining member and the joined member easily coming apart when a rotational force is applied.

[0005] The present invention was created in consideration of the above problem, and aims to provide a terminal for a secondary battery in which the connection between the joining member and the joined member is unlikely to come loose even when a rotational force is applied. [Means for solving the problem]

[0006] The present invention was created in consideration of the above-mentioned problems, and provides a terminal for a secondary battery having a metal joining member and a metal joined member that is joined to the joining member, wherein the joining member and the joined member are joined by fitting a joining recess formed on one of them with a joining protrusion formed on the other that fits into the joining recess, and the centers of the joining recess and the joining protrusion are offset from the center of the joining interface between the joining member and the joined member when viewed in a plane. Preferably, the joining member has a plurality of joining recesses or joining protrusions. It is also preferable that the joining member is formed with both the joining recess and the joining protrusion. [Effects of the Invention]

[0007] In the terminal of the secondary battery manufactured according to the present invention, the centers of the joining recess and the joining protrusion are offset from the center of the joining interface, so that when a rotational force is applied, the joining recess and the joining protrusion have a rotation-preventing effect, which has the advantage that the joining member and the joined member are less likely to come loose. In addition, if the joining member has multiple joining recesses or joining protrusions, or if both the joining recesses and the joining protrusions are formed, there are also advantages such as improved anti-rotation and anti-disconnection effects. [Brief explanation of the drawings]

[0008] [Figure 1] 1A and 1B are diagrams showing the part shape of a terminal of a secondary battery before being joined by the present invention, in which FIG. 1A is a side view showing the structure of the joined member, and FIG. 1B is a side view showing the structure of the joining member. [Figure 2] 1 is a side view showing the structure of a terminal of a secondary battery according to the present invention. [Figure 3] 1 is a plan view showing the structure of a terminal of a secondary battery according to the present invention. [Figure 4] 1 is a side view showing a method for joining terminals of a secondary battery according to the present invention; [Figure 5]FIG. 5 is a side view showing a state transitioning from FIG. 4 to the next state. [Figure 6] 1 is a perspective view showing the structure of a terminal of a secondary battery according to the present invention. [Figure 7] FIG. 4 is a side view showing the structure of a second embodiment of a terminal of a secondary battery according to the present invention. [Figure 8] FIG. 4 is a plan view showing the structure of a terminal of a secondary battery according to a second embodiment of the present invention. [Figure 9] FIG. 10 is a side view showing the structure of a terminal of a secondary battery according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a plan view showing the structure of a terminal of a secondary battery according to a third embodiment of the present invention. [Figure 11] FIG. 10 is a perspective view showing the structure of a terminal of a secondary battery according to a third embodiment of the present invention. [Figure 12] FIG. 10 is a side view showing the structure of a fourth embodiment of a terminal of a secondary battery according to the present invention. [Figure 13] FIG. 10 is a plan view showing the structure of a fourth embodiment of a terminal of a secondary battery according to the present invention. [Figure 14] FIG. 10 is a perspective view showing the structure of a terminal of a secondary battery according to a fourth embodiment of the present invention. [Figure 15] FIG. 10 is a side view showing the structure of a fifth embodiment of a terminal of a secondary battery according to the present invention. [Figure 16] FIG. 10 is a plan view showing the structure of a terminal of a secondary battery according to a fifth embodiment of the present invention. [Figure 17] FIG. 10 is a side view showing the structure of a terminal of a secondary battery according to a sixth embodiment of the present invention. [Figure 18] FIG. 10 is a plan view showing the structure of a terminal of a secondary battery according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] A first embodiment of the method for joining dissimilar metal components according to the present invention will be described below with reference to the drawings. Figures 1(a) and 1(b) show the shape of a metal joined body before joining, in which a joining member 10 made of copper material shown in Figure 1(b) is joined to a joined member 20 made of aluminum material shown in Figure 1(a). The joining member 10 and the joined member 20 are formed and prepared separately in advance, for example, by cold heading or cutting.

[0010] The joining member 10 is composed of a flat head portion 11 and a shaft portion 12 integrally formed therewith. A joining recess 13 with a bottom is provided on the top surface of the head portion 11 at a position offset from the center of the head portion 11.

[0011] The joining recess 13 is a blind hole whose inner peripheral wall is formed in an inverse tapered shape, and this inverse tapered portion is inclined in the direction in which the joining recess 13 widens from the opening toward the bottom.

[0012] The member to be joined 20 is cylindrical, and its end 21 is formed to be sufficiently larger than the opening area of ​​the joining recess 13 of the joining member 10, and has a protrusion that can be inserted into the joining recess 13.

[0013] 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.

[0014] 5 and 6 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.

[0015] Next, as shown in Figure 5, the end 21 of the workpiece 20 is placed so as to block the joining recess 13 of the joining member 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. This fills the joining recess 13 of the joining member 10. At the same time, the workpiece 20 is flattened by the compressive force.

[0016] As shown in Figure 6, the joining member 10 and the member to be joined 20 are joined by completely filling the joining recess 13 of the joining member 10 with the end 21 of the member to be joined 20 and compressing the member to be joined 20 until it becomes flat.

[0017] 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.

[0018] In the terminal of a secondary battery manufactured by the above joining method, as shown in Fig. 4, a joining protrusion 23 of the same shape as the joining recess 13 is formed at the end 21 of the joined member 20, and the joining protrusion 23 catches on the joining recess 13 in the pulling direction, resulting in high pull-out strength. Also, the joining recess 13 of the joined member 10 is completely filled with the joining protrusion 23 of the joined member 20, resulting in high adhesion. Furthermore, as shown in Fig. 3, the center of the joining recess 13 is positioned off-center from the center of the joining interface between the joining member 10 and the joined member 20 in a plan view, which provides a rotation prevention effect.

[0019] 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.

[0020] Other embodiments will be described below with reference to Figures 7 to 18. The second example shown in Figures 7 and 8 is a terminal for a secondary battery having a joint protrusion 14 that protrudes toward the joined members 20 from the upper surface of the head 11 of the joining member 10. Like the joint recess 13, this joint protrusion 14 is located at a position offset from the center of the head 11. This joint protrusion 14 has an inverted tapered shape with its top protruding outward from its base, and this inverted tapered portion is inclined in the direction in which the joint protrusion 14 widens as it moves from the base to the top. Therefore, during joining, a blind-hole-shaped joint recess 24 that fits into the joint protrusion 14 is formed in the end 21 of the joined members 20, and the engagement of this joint recess 24 and joint protrusion 14 prevents the joining member 10 and the joined members 20 from slipping out.

[0021] In the second embodiment, the end 21 of the workpiece 20 may be provided with a recess capable of accommodating the joining protrusion 14. In this second embodiment, as in the first embodiment, the center of the joining protrusion 14 is positioned at a position offset from the center of the joining interface in a plan view, and therefore, a rotation-preventing effect is provided.

[0022] Similarly, in a third embodiment shown in Figures 9 to 11, both a joining recess 13 and a joining protrusion 14 are provided on the upper surface of the joining member 10. In a fourth embodiment shown in Figures 12 to 14, a joining recess 13 and a joining protrusion 14 each configured in a semi-frustum shape are formed near the center of the joining member 10. The joining recess 13 and the joining protrusion 14 in these embodiments are both configured in an inverted tapered shape, with the bottom or top wider than the opening or base. In these embodiments, the joining recess 13 and the joining protrusion 14 are also formed at positions eccentric to the center of the joining interface in a plan view, thereby providing a rotation-preventing effect.

[0023] 15 and 16, the joining recess 13 has a further recess formed on the bottom surface of the inverted tapered shape, and in the sixth embodiment shown in Figures 17 and 18, a recess is formed on the top surface of the joining protrusion 14. In this way, there is no problem even if the joining recess 13 and the joining protrusion 14 have a multi-step shape, a ring shape, or the like.

[0024] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, the joining recess 13 and joining protrusion 14 of the joining member 10 are both examples of joining portions that provide a catch in the removal direction. As long as a retaining portion wider than the opening is formed midway, they may be configured in any shape other than circular as in the fourth embodiment. Furthermore, before joining, the end 21 of the joined member 20 may be formed with irregularities that can enter the joining recess 13 of the joining member 10 or accommodate the joining protrusion 14, or it may be a smooth surface without irregularities. [Explanation of symbols]

[0025] 10... Joint material 11 … Head 12 ... Shaft 13 ... Joint recess 14 ... Joint recess 20... Joint material 23 ... Joint recess 24 ... Joint recess 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 a metal member to be joined to the joining member, The joining member and the joined member are joined by fitting a joining recess formed on one of them with a joining protrusion formed on the other member that fits into the joining recess, A terminal for a secondary battery, wherein the centers of the joining recess and the joining protrusion are offset from the center of the joining interface between the joining member and the joined member in a plan view.

2. 2. The terminal of a secondary battery according to claim 1, wherein the joining member has a plurality of joining recesses or joining protrusions.

3. 2. The terminal of a secondary battery according to claim 1, wherein the joining member is formed with both the joining recess and the joining protrusion.

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