Terminals of a secondary battery

Abstract

This invention provides a terminal for a secondary battery that exhibits excellent adhesion between the joining component and the member to be joined. [Solution] The terminal for a secondary battery comprises a metal joining member 10 and a metal member to be joined 20 which is joined to the joining member 10, wherein the joining member 10 has an annular projection 14 into which the member to be joined 20 fits, and the thickness or height of the annular projection 14 changes in the circumferential direction. The joining member 10 and the member to be joined are joined by the fitting of a joining recess 13 formed on one of them and a joining projection 14 formed on the other which fits into the joining recess 13, and it is preferable that the inner circumferential surface of the annular projection 14 is located on the outer circumferential side of the opening of the joining recess 13.

Description

Technical Field

[0001] The present invention relates to a terminal of a secondary battery formed by joining different metal members together.

Background Art

[0002] Conventionally, as a terminal of a secondary battery formed by joining different metals together, the one shown in Patent Document 1 is known. In this terminal of the secondary battery, the central portion of the joined member flows into and is joined to a joined recess formed in the joining member by pressing a rod-shaped joining member made of a copper material and a plate-shaped joined member made of an aluminum material together. Such a terminal of a secondary battery is used as a negative electrode terminal of a lithium ion battery.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a conventional terminal of a secondary battery, the joined recess is provided on the central axis, and the joined interface has a uniform structure in the circumferential direction. Therefore, when a force in the rotational direction is applied, there are problems such as the joining between the joining member and the joined member being easily disengaged.

[0005] The present invention was created in view of the above problems, and an object thereof is to provide a terminal of a secondary battery in which the joining between the joining member and the joined member is not easily disengaged even when a force in the rotational direction is applied.

Means for Solving the Problems

[0006] The present invention was created in view of the above problems, and is a terminal for a secondary battery having a metal joining member and a metal member to be joined to the joining member, wherein the joining member has an annular projection formed thereon into which the member to be joined fits, and is characterized in that the thickness or height of the annular projection changes in the circumferential direction. Furthermore, the joining member and the member to be joined are joined by the fitting of a joining recess formed on one of them and a joining projection formed on the other that fits into the joining recess, and it is preferable that the inner circumferential surface of the annular projection is located on the outer circumferential side of the opening of the joining recess. Furthermore, it is preferable that the outer circumferential surface of the annular protrusion is continuous with the outer circumferential surface of the joining member. Furthermore, it is preferable that the joining member has higher rigidity than the member to be joined. [Effects of the Invention]

[0007] The terminals of the secondary battery manufactured according to the present invention have a thickness or height that varies in the circumferential direction of the annular projection formed on the joining member. Therefore, when a rotational force is applied, the joining recess and the joining projection have an anti-rotation effect. This provides advantages such as making it difficult for the joining member and the joined member to come apart. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows the shape of the components before joining the terminals of the secondary battery according to the present invention, where (a) is a side view showing the shape of the member to be joined, and (b) is a side view showing the shape of the joining member. [Figure 2] This is a side view showing the shape of the terminals of the secondary battery according to the present invention. [Figure 3] This is a plan view showing the shape of the terminals of the secondary battery according to the present invention. [Figure 4] This is a side view showing a method for joining terminals of a secondary battery according to the present invention. [Figure 5] This is a side view showing the state after transitioning from Figure 4 to the next state. [Figure 6]This figure shows the shape of the components before joining a second embodiment of the terminals of a secondary battery according to the present invention, where (a) is a side view showing the shape of the member to be joined, and (b) is a side view showing the shape of the joining member. [Figure 7] This is a side view showing the shape of a second embodiment of the terminals of a secondary battery according to the present invention. [Modes for carrying out the invention]

[0009] The first embodiment for implementing the present invention's method for joining dissimilar metal parts will be described below with reference to the drawings. Figures 1(a) and 1(b) show the shape of the metal joint before joining, where a joining member 10 made of copper material shown in Figure 1(b) and a member to be joined 20 made of aluminum material shown in Figure 1(a) are joined. These joining member 10 and member to be joined 20 are formed separately in advance, for example, by cold forging or machining.

[0010] The joining member 10 consists of a flat plate-shaped head portion 11 and a shaft portion 12 integrally molded therewith. The upper surface of the head portion 11 is provided with a bottomed joining recess 13 and an annular projection 14 located on the outer circumference side of the joining recess 13.

[0011] The aforementioned joint recess 13 is a blind hole whose inner circumferential wall is formed in an inverse tapered shape, and this inverse tapered portion is inclined in a direction that causes the joint recess 13 to widen as it moves from the opening toward the bottom.

[0012] The annular projection 14 is formed such that its outer circumferential surface is continuous with the outer edge of the head 11, while the center of its inner circumferential surface is offset from the center of the head 11, and its thickness varies in the circumferential direction.

[0013] The member to be joined 20 is cylindrical in shape, and its end portion 21 is formed to be sufficiently larger than the opening area of ​​the joining recess 13 of the joining member 10, and a projection 22 that can be inserted into the joining recess 13 is formed thereon.

[0014] By joining these joining members 10 and the joined member 20, the terminal of the secondary battery shown in FIG. 2 is manufactured.

[0015] FIGS. 4 and 5 are diagrams showing a joining method of the joining member 10 and the joined member 20. The receiving die 100 has a stepped insertion hole 101. The head portion 11 of the joining member 10 is suspended from the stepped portion, and the shaft portion 12 of the joining member 10 is loosely fitted into the insertion hole 101 so that the joining member 10 is held in the insertion hole 101.

[0016] Subsequently, as shown in FIG. 4, the end portion 21 of the joined member 20 is installed so as to close the joining recess 13 of the joining member 10. Then, the punch pin 200 is advanced downward, and the joined member 20 is compressed in the axial direction from the other end portion 23 side of the joined member 20, so that the end portion 21 of the joined member 20 flows by plastic deformation. Thereby, it is filled into the joining recess 13 of the joining member 10. At the same time, the joined member 20 is flattened by the compressive force. At this time, the annular convex portion 14 of the joining member 10 is pressed radially outward by the flattened joined member 20, and thus inclines so as to widen toward the top.

[0017] As shown in FIG. 5, the end portion 21 of the joined member 20 is completely filled into the joining recess 13 of the joining member 10, and by compressing until the joined member 20 becomes flat plate-like, the joining member 10 and the joined member 20 are joined.

[0018] When the joining is completed, the knockout pin 102 disposed below the insertion hole 101 of the receiving die 100 is advanced upward, whereby the terminal of the secondary battery is discharged from the receiving die 100.

[0019] The terminal of the secondary battery manufactured by the above joining method is formed with a joining convex portion 24 having the same shape as the joining concave portion 13 at the end portion 21 of the joined member 20 as shown in FIG. 3. Since the joining convex portion 24 is caught in the direction of coming off from the joining concave portion 13, a high pull-off strength can be obtained. Further, since the joining convex portion 24 of the joined member 20 completely fills the joining concave portion 13 of the joining member 10, high adhesion can be obtained. Further, as shown in FIG. 4, in a plan view, the center of the annular convex portion 14 is provided at a position shifted from the center of the joining interface between the joining member 10 and the joined member 20, and the thickness of the annular convex portion 14 changes in the circumferential direction. By changing the thickness in the circumferential direction in this way, it has a rotation prevention effect, and when a force in the rotation direction is applied, it becomes difficult for the joining member 10 and the joined member 20 to come off.

[0020] The terminal of the secondary battery having such an operation and effect is suitable, for example, as an application to the negative electrode terminal of a lithium ion battery (not shown). 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 outside the lithium ion battery and connected to a bus bar (not shown). Since the terminal of the secondary battery manufactured by the present invention is joined with high adhesion, it has excellent electrical conductivity. Therefore, when it is used as the negative electrode terminal of a lithium ion battery, the electrical resistance value can be kept low.

[0021] Hereinafter, a second embodiment will be described. FIGS. 6(a) and 6(b) show the shape of the second metal joined body before joining. A joining member 30 made of a copper material shown in FIG. 6(b) and a joined member 20 made of an aluminum material shown in FIG. 6(a) are joined. These joining member 30 and joined member 20 are also separately formed and prepared in advance, similar to the first embodiment, and are formed by, for example, cold forging or cutting.

[0022] The joining member 30 is also composed of a flat head portion 31 and a shaft portion 32 integrally formed therewith, similar to the joining member 10. On the upper surface of the head portion 31, a bottomed joining concave portion 33 and an annular convex portion 34 located on the outer peripheral side of the joining concave portion 33 are provided.

[0023] The aforementioned joint recess 33 is a blind hole whose inner circumferential wall is formed in an inverse tapered shape, and this inverse tapered portion is inclined in a direction that causes the joint recess 33 to widen as it moves from the opening toward the bottom.

[0024] The annular projection 34 is configured to have a circular shape in plan view, with its outer circumferential surface being continuous with the outer edge of the head portion 31, and is configured such that its height dimension changes in the circumferential direction, as shown in Figure 6.

[0025] The member to be joined 20 is cylindrical in shape, and its end portion 21 is formed to be sufficiently larger than the opening area of ​​the joining recess 33 of the joining member 10, and a projection 22 that can be inserted into the joining recess 13 is formed thereon.

[0026] When these joining members 30 and the member to be joined 20 are pressed using the receiving mold 100 and punch pin 200, similar to the joining member 10 and the member to be joined 20, the end portion 21 of the member to be joined 20 flows due to plastic deformation and fills the joining recess 33 of the joining member 30, and the member to be joined 20 is flattened by the compressive force. At this time, the annular protrusion 34 of the joining member 30 is pressed radially outward by the flattened member to be joined 20 and inclined to widen towards the top, thereby manufacturing the terminals of the secondary battery shown in Figure 7.

[0027] As shown in Figure 7, the terminals of the secondary battery manufactured by the above joining method also have the end portion 21 of the member to be joined 20 filled into the joining recess 33, forming a joining projection 24 that is the same shape as the joining recess 33. As a result, both the joining member 30 and the member to be joined 20 have high pull-out strength and high adhesion. Furthermore, as shown in Figure 7, the height of the annular projection 34 changes gradually in the circumferential direction, which has an anti-rotation effect, making it difficult for the joining member 30 and the member to be joined 20 to come apart when a rotational force is applied.

[0028] Furthermore, the present invention is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the invention. For example, in the above embodiment, the terminals of the secondary battery were configured such that a joining recess 13 was formed on the joining member 10 and a joining protrusion 24 was formed on the member to be joined 20, but there is no problem if the opposite is true, with a joining protrusion 24 formed on the joining member 10 and a joining recess 13 formed on the member to be joined 20. Also, although a projection 22 was formed on the end 21 of the member to be joined 20, there is no problem if it is a flat surface without a projection 22. Moreover, in the above embodiment, the annular protrusions 14 and 34 of the joining member 10 were configured such that only their thickness or height changed in the circumferential direction, but there is no problem if both the thickness and height changed in the circumferential direction. [Explanation of Symbols]

[0029] 10,30 … Joining members 13,33 … Joint recess 14 … Ring-shaped protrusion 20 … Parts to be joined 24 ... Joint protrusion 100... Receiving type 101… Insertion hole 102… Knockout pin 200... Punch pin

Claims

1. Metal connecting member, It has a metal member to be joined to the aforementioned joining member, The connecting member is a terminal of a secondary battery having an annular projection formed therein into which the member to be connected fits, A terminal for a secondary battery, characterized in that the thickness or height of the annular protrusion changes in the circumferential direction.

2. The joining member and the member to be joined are joined by the fitting of a joining recess formed on one of them and a joining projection formed on the other that fits into the joining recess. The terminal of the secondary battery according to claim 1, characterized in that the inner surface of the annular projection is located on the outer side of the opening of the joining recess.

3. The terminal of the secondary battery according to claim 1, characterized in that the outer circumferential surface of the annular protrusion is continuous with the outer circumferential surface of the joining member.

4. The terminal of the secondary battery according to claim 1, characterized in that the joining member has higher rigidity than the member to be joined.

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