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 20 which is joined with the junction member 10 so as not to be removed. In the terminal for the secondary battery, the junction member 10 has a rough surface part 14 in a junction interface with the joined member 20, and the joined member 20 is adhered with the rough surface part 14 of the junction member 10 with no gap. In the terminal for the secondary battery, the rough surface part 14 is made uneven by satin processing. Further, the rough surface part 14 is a minute groove which is far smaller than a fitting part 13.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 joined to the joining member so that it cannot be removed, wherein the joining member has a rough surface portion at the joining interface with the joined member, and the joined member is in close contact with the rough surface portion of the joining member without any gaps. The rough surface is preferably uneven due to matte finish. Alternatively, the rough surface portion is preferably a minute groove that is much smaller than the fitting portion.

[0007] A second object of the present invention is to provide a method for manufacturing a terminal of the secondary battery, which includes a step of forming a rough surface portion on the joining member, which comprises a metal joining member and a metal joinee member overlaid on the joining member, a step of overlaying the joinee member on the joining member, and a pressurizing step of pressurizing the joinee member and the joining member, thereby plastically deforming the joinee member so that it flows along the joining member, thereby bringing the joinee member and the joining member into close contact with each other, wherein the joinee member is deformed so as to adhere to the rough surface portion during the pressurizing step. [Effects of the Invention]

[0008] The terminal of the secondary battery manufactured according to the present invention has an advantage that a rough surface portion is formed on the joining member, and the joined member deforms along the rough surface portion of the joining member, thereby exhibiting high adhesion.

[0009] In addition, the manufacturing method of the terminal of the secondary battery includes the steps of: deforming the contact member along the rough surface portion provided on the joining member; Therefore, it is only necessary to form the rough surface portion on the joining member, which has the advantage that it can be manufactured relatively inexpensively. [Brief explanation of the drawings]

[0010] [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 (a) is a side view showing the shape of the joined member, and (b) is a side view showing the shape of the joining member. [Figure 2]1 is a side view showing the shape of a terminal of a secondary battery according to the present invention. [Figure 3] 2 is an enlarged schematic side view of a main portion showing a bonding interface of a battery terminal according to the present invention. FIG. [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] 10 is a schematic plan view showing a joining member of another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 7] 10 is a schematic plan view showing a joining member of another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 8] 10 is a schematic plan view showing a joining member of another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 9] 10 is an enlarged schematic side view of a main portion showing a bonding interface of another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 10] 10 is an enlarged schematic side view of a main portion showing a bonding interface of another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 11] 10 is an enlarged schematic side view of a main portion showing a bonding interface of another embodiment of a terminal of a secondary battery according to the present invention. FIG. [Figure 12] 10 is an enlarged schematic side view of a main portion showing a bonding interface of another embodiment of a terminal of a secondary battery according to the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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.

[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 this blind hole portion 13 is provided therein.

[0013] The blind hole portion 13 is formed in an inverse tapered shape with the opening projecting inward from the bottom, and this inverse tapered portion 131 is inclined in the direction in which the blind hole portion 13 widens as it approaches the bottom.

[0014] A rough surface portion 14 is formed on the upper surface of the head portion 11 on the outer periphery of the blind hole portion 13. This rough surface portion 14 is matte-finished by sandblasting or the like, and has many irregularities that are much smaller than the blind hole portion 13.

[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 workpiece 10 .

[0016] The joining member 10 and the member to be joined 20 are joined together to produce the terminal of the secondary battery shown in FIG.

[0017] 4 is a diagram 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 Figure 4, 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 blind hole 13 of the head 11 of the workpiece 10 is filled as shown in Figure 5. At the same time, the workpiece 20 is flattened by the compressive force. At this time, the workpiece 20 is deformed along the rough surface 14 of the workpiece 10.

[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 at the center because the reverse tapered portion 131 of the joining member 10 catches the terminal against the pull-out direction as shown in Fig. 2. 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, as shown in Fig. 3, the joined member 20 deforms along the rough surface 14 of the joining member 10, resulting in high adhesion even at the outer periphery of the blind hole 13.

[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] The present invention is not limited to the above embodiment and various modifications are possible without departing from the spirit of the present invention. For example, the blind hole portion 13 is an example of a fitting portion for fitting the joining member 10 and the workpiece 20. It is not limited to a blind hole, but may be a protrusion protruding toward the workpiece 20. The shape of the protrusion is not limited to the inverted tapered shape described above, and may be a barrel shape with an expanded diameter at the axial center, a bipyramidal shape, or other shapes. Furthermore, the workpiece 20 may have a shaft portion that can enter the blind hole portion 13 or a recess that can accommodate the protrusion. Furthermore, the rough surface portion 14 may be provided on the entire upper surface of the head 11 or only on a portion thereof. The surface of the fitting portion may have an unevenness similar to that of the rough surface portion 14. By providing unevenness on the upper surface of the joining member 10, or on the other surface where the flat surfaces of the joining member 10 and the workpiece 20 come into contact, the workpiece 20 deforms along the unevenness of the joining member 10. Therefore, the adhesion between the joining member 10 and the joined member 20 is improved in areas other than the blind hole portion 13 as well.

[0024] In the above embodiment, the rough surface portion 14 of the joining member 10 is formed by a matte finish such as sandblasting to form uneven projections and depressions. However, the present invention is not limited to this. The rough surface portion 14 may be formed by matte finishing when the joining member 10 is formed by pressing, or the uneven surface projections and depressions caused by plating the joining member 10 may be used as the rough surface portion 14. Alternatively, a large number of fine grooves much shallower and smaller than the blind holes 13 may be formed on the upper surface of the head 11 of the joining member 10. Furthermore, the fine grooves may be circular as shown in Fig. 6, radial as shown in Fig. 7, lattice as shown in Fig. 8, or spiral as shown, and the cross-sectional shape may be rectangular as shown in Fig. 9, V-shaped as shown in Fig. 10, trapezoidal as shown in Fig. 11, or semicircular. There is no problem even if the grooves have different heights as shown in Fig. 12. It is preferable that the depth of these minute grooves is set in the range of 0.1 mm to 0.5 mm, and the width of the groove is set in the range of 0.5 mm to 2 mm. [Explanation of symbols]

[0025] 10... Joint material 11 … Head 12 ... Shaft 13 … Blind hole part 131... Tapered section 14 … Rough surface area 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 has a rough surface portion at a joining interface with the joined member, The terminal of a secondary battery is characterized in that the member to be joined is in close contact with the rough surface portion of the joining member without any gaps.

2. 2. The terminal of a secondary battery according to claim 1, wherein the rough surface portion is formed by matte finishing.

3. 2. The terminal of claim 1, wherein the rough surface portion is a minute groove that is much smaller than the fitting portion.

4. A metal joining member; a metal member to be joined that is placed on the joining member; forming a rough surface portion on the joining member; a step of placing a member to be joined on the joining member; a pressurizing step of pressurizing the workpieces and the joining member, thereby plastically deforming the workpieces so that they flow along the joining member, thereby bringing the workpieces and the joining member into close contact with each other; The method for manufacturing a terminal for a secondary battery, wherein the member to be joined is deformed so as to come into close contact with the rough surface portion during the pressing step.

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