Battery negative terminal external terminal

Abstract

This provides a lightweight negative terminal for batteries. [Solution] The problem can be solved by a negative electrode external terminal of a battery, which is constructed by mechanically joining a first metal member 10 and a lighter second metal member 20, comprising: a first metal member having an axial through hole 12a, communicating with the through hole and having a fitting hole portion 11a larger in diameter than the through hole; and a second metal member having a protrusion 21a that fills and fits into the fitting hole portion of the first metal member and is integrally joined with the first metal member.

Description

Technical Field

[0001] The present invention relates to a negative electrode external terminal of a battery that is welded to a bus bar or the like and connected to a terminal when forming a battery pack.

Background Art

[0002] What is shown in Patent Document 1 is a negative electrode external terminal of a lithium ion battery, which is configured by joining two members by press-fitting a solid rod-shaped member made of a copper material into a concave portion of a plate-shaped body made of an aluminum material.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] With the spread of electric vehicles, the demand for in-vehicle lithium ion batteries has been continuously expanding and is expected to continue to expand in the future. However, in-vehicle lithium ion batteries have a problem of weight when mounting a large capacity to extend the cruising range.

[0005] The present invention was created in view of the above problems, and an object thereof is to provide a negative electrode external terminal of a battery that contributes to weight reduction.

Means for Solving the Problems

[0006] The above problems can be solved by a negative electrode external terminal of a battery configured by mechanically joining a first metal member and a second metal member lighter than the first metal member, the first metal member having a through hole in the axial direction, a fitting hole portion communicating with the through hole and having a larger diameter than the through hole, and a second metal member having a convex portion filled and fitted into the fitting hole portion of the first metal member and joined integrally with the first metal member.

[0007] Furthermore, it is preferable that the opening diameter of the fitting hole portion of the first metal member is set to be smaller than the outer diameter of the bottom portion.

[0008] Furthermore, it is preferable that the protrusion of the second metal member fills a portion of the through hole that communicates with the fitting hole of the first metal member. [Effects of the Invention]

[0009] According to the present invention, in the negative electrode external terminal of a battery constructed by joining dissimilar metals, the first metal member is configured as a hollow shape with a through hole in the axial direction, and a lightweight second metal member is filled into this hole and joined, resulting in excellent weight reduction. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows the shape of the components constituting the negative electrode external terminal of the battery according to the present invention before joining. [Figure 2] This figure shows the manufacturing process of the negative electrode external terminal of the battery according to the present invention. [Figure 3] This figure shows the completed state of the negative electrode external terminal of the battery according to the present invention. [Figure 4] This figure shows a modified example of the present invention. [Figure 5] This figure shows a second modified example of the present invention. [Modes for carrying out the invention]

[0011] The structure of the negative electrode external terminal of the battery according to the present invention and its manufacturing method will be described below with reference to the drawings.

[0012] Figure 1 shows the shape of the components constituting the negative electrode external terminal of the battery before joining. A first metal component 10 made of copper material, as shown in Figure 1(b), and a second metal component 20 made of aluminum material, as shown in Figure 1(a), are joined together. These first metal component 10 and second metal component 20 are formed separately in advance, for example, by cold forging.

[0013] The first metal member 10 consists of a flat head portion 11 and a shaft portion 12 integrally molded therewith. The shaft portion 12 has a through hole 12a formed along its axis, and the head portion 11 has a fitting hole portion 11a that communicates with the through hole 12a and has an opening 11b on the upper surface of the head portion 11. The inner circumferential wall of this fitting hole portion 11a is formed in an inverse tapered shape. Specifically, the opening diameter of the opening 11b of the fitting hole portion 11a is set to be smaller than the outer diameter of the bottom portion 11c of the fitting hole portion 11a, and the outer diameter of the inner circumferential wall of the fitting hole portion 11a is inclined to gradually widen towards the bottom portion 11c.

[0014] The second metal member 20 is cylindrical in shape, and its end portion 21 is formed to be sufficiently larger than the opening area of ​​the fitting hole portion 11a of the first metal member 10.

[0015] Figure 2 shows a method for joining the first metal member 10 and the second metal member 20. The receiving mold 1 has a stepped insertion hole 1a, and the head portion 11 of the first metal member 10 is suspended from the stepped portion, and the shaft portion 12 of the first metal member 10 is loosely fitted into the insertion hole 1a, thereby holding the first metal member 10 in the insertion hole 1a.

[0016] Subsequently, the lower end portion 21 of the second metal member 20 is installed so as to close the opening 11b of the fitting hole portion 11a of the first metal member 10. Then, as shown in FIG. 3, the punch pin 3 is advanced downward to compress the second metal member 20 in the axial direction from the other end portion 22 side of the second metal member 20, so that the end portion 21 of the second metal member 20 flows due to plastic deformation and is filled into the fitting hole portion 11a of the first metal member 10. At the same time, the second metal member 20 is flattened by the compressive force.

[0017] Subsequently, as shown in FIG. 3, until the end portion 21 of the second metal member 20 is completely filled in the through hole 12a communicating with the fitting hole portion 11a, by compressing the second metal member 20, the first metal member 10 and the second metal member 20 are joined.

[0018] When the joining is completed, by advancing the knockout pin 2 disposed below the insertion hole 1a of the receiving mold 1 upward, the negative electrode external terminal of the battery is discharged from the receiving mold 1.

[0019] The negative electrode external terminal of the battery manufactured by the above joining method and formed by joining the first metal member 10 and the second metal member 20 has a reverse tapered inner peripheral wall of the fitting hole portion 11a, so it catches in the removal direction, and thus a high removal strength can be obtained. Also, since the end portion 21 of the second metal member 20 is completely filled in the fitting hole portion 11a and the through hole 12a of the first metal member 10, a high adhesion can be obtained. Furthermore, since the first metal member 10 is formed in a hollow shape having a through hole 12a instead of being solid, it contributes to weight reduction.

[0020] The negative electrode external terminal of a battery having such an effect is suitable, for example, for use as a negative electrode terminal of a lithium-ion battery (not shown). The shaft portion 12 of the first metal member 10 is connected to a current collector plate (not shown) inside the lithium-ion battery, and the second metal member 20 is exposed outside the lithium-ion battery and connected to a bus bar (not shown). Since the negative electrode external terminal of the battery manufactured according to 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, and since it is lightweight, an improvement in the cruising range can be expected when mounted on an electric vehicle.

[0021] FIG. 4 shows a modified example of the present invention. The difference from the above-described embodiment is the shape of the second metal member 20 before joining, and the other aspects are the same as those of the above-described embodiment. Specifically, the second metal member 20 before joining has a convex portion 21a at the end portion 21. The second metal member 20 is compressed and joined in a state where the convex portion 21a is inserted into the fitting hole portion 11a and the through hole 12a of the first metal member 10. By doing so, the end portion 21 of the second metal member 20 is surely and completely filled in the fitting hole portion 11a and the through hole 12a of the first metal member 10.

[0022] FIG. 5 shows a second modified example of the present invention. A convex portion 2a is provided at the tip of the knockout pin 2, and the second metal member 20 is compressed in a state where the convex portion 2a is inserted downward into the through hole 12a of the first metal member 10. Thereby, it is also possible to manufacture a negative electrode external terminal of a battery in which both members are joined in a form in which the end portion 21 of the second metal member 20 fills a part of the through hole 12a.

[0023] Note that 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.

[0024] 1 Receiver type 1a Insertion hole 2 Knockout pin 2a Convex portion 3 Punch pin 10 First metal member 11 Head 11a Fitting hole 11b opening 11c bottom 12 Shaft section 12a Through hole 20 Second metal component 21, 22 End 21a Convex part

Claims

1. In the negative terminal external terminal of a battery, which is constructed by mechanically joining a first metal member and a second metal member that is lighter thereunder, A first metal member having a through hole in the axial direction, communicating with this through hole, and having a fitting hole portion with a larger diameter than the through hole, A second metal member having a protrusion that fills and fits into the fitting hole of the first metal member, and being integrally joined with the first metal member, A negative terminal external terminal of a battery, characterized by being composed of the following.

2. The negative electrode external terminal of the battery according to claim 1, characterized in that the opening diameter of the fitting hole of the first metal member is set to be smaller than the outer diameter of the bottom.

3. The negative electrode external terminal of a battery according to claim 1 or 2, characterized in that the protrusion of the second metal member fills a portion of the through hole that communicates with the fitting hole of the first metal member.

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