Method for manufacturing battery external terminal

Abstract

To provide a method of manufacturing a high-quality negative electrode external terminal with improved productivity.SOLUTION: In a method of manufacturing a battery outer terminal 1 in which a convex portion 13 of a metal joining member 10 and a concave portion 21 of a metal joined member 20 are pressed in a compressing direction in a state where the convex portion 13 is fitted into the concave portion 21, an end surface outer periphery of the convex portion 13 of the joining member 10 is flattened outward to form an undercut portion 13a, and both members are integrally joined.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an external battery terminal used on the negative electrode side of a secondary battery. [Background technology]

[0002] Patent Document 1 discloses a known negative electrode external terminal for lithium-ion secondary batteries. This negative electrode external terminal is constructed by compressing and plastically deforming a copper member and an aluminum member that are fitted together, thereby forming the two members into a desired shape and mechanically joining them. As a result, the copper member is formed into a circular head, and the aluminum member is formed into a shaft shape. In the negative electrode external terminal constructed in this manner, the aluminum member side is connected to a power generating element inside the lithium-ion secondary battery, and the copper member side is exposed from the casing of the lithium-ion secondary battery and connected to a bus bar. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-176285 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional negative electrode external terminals, the circular head portion must be trimmed to a desired shape, resulting in low productivity. Therefore, when plastic deformation is performed by compression while the outer periphery of the copper member is constrained to have the desired shape, there is a problem of burrs being generated on the outer periphery.

[0005] The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for manufacturing a high-quality negative electrode external terminal with improved productivity. [Means for solving the problem]

[0006] The above-mentioned problem can be solved by a method for manufacturing an external terminal for a battery, in which the convex portion of a metal joining member is fitted into the concave portion of a metal joinee member and pressure is applied in a direction compressing both members, thereby flattening the outer periphery of the end face of the convex portion of the joining member outward to form an undercut portion, and joining both members together, by a receiving mold that supports the joining member and restrains the outer shape of the joinee member that plastically deforms due to compression, in a method for manufacturing an external terminal for a battery, in which the outer periphery of the joinee member is molded into a stepped shape.

[0007] The receiving mold preferably restrains the lower side of the outer periphery of the workpieces while leaving the upper side unrestrained, thereby forming the outer periphery of the workpieces into a stepped shape. This can be solved by: [Effects of the Invention]

[0008] According to the present invention described above, the outer peripheral edge of the joined member is formed into a stepped shape during the plastic deformation process due to compression, so that no burrs are generated there, making it possible to produce a high-quality negative electrode external terminal. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing a state before joining of an external terminal for a battery manufactured according to the present invention. [Figure 2] 1A to 1C are diagrams showing a joining process for a battery external terminal manufactured according to the present invention. [Figure 3] 1A to 1C are diagrams showing a finishing process for an external battery terminal manufactured according to the present invention. [Figure 4] 1 is a perspective view of an external terminal for a battery manufactured according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a method for manufacturing an external terminal for a battery according to the present invention will be described with reference to the drawings.

[0011] First, as shown in FIG. 1 , in the manufacturing method for an external terminal for a battery, a cylindrical joining member 10 made of a copper material having a shaft portion 11, a flange portion 12, and a protrusion 13, a member to be joined 20 made of a cylindrical aluminum alloy material having a recess 21 formed therein that abuts against the flange portion 12 and fits into the protrusion 113, and a receiving die 3 and a pressing die 4 that are arranged so that these two members can be pressed together are used, and the member to be joined 20 is integrally joined to the joining member 10 by applying pressure with the pressing die 4 to manufacture an external terminal for a battery on the negative electrode side.

[0012] The receiving die 3 has an expanded hole 3a that guides a part of the workpiece 20, and a positioning hole 3b that communicates with the expanded hole 3a and positions the shaft 11 of the joining member 10. A knockout pin 5 that extends concentrically with the positioning hole 3b is arranged so as to be able to protrude, and the end face of the knockout pin 5 is configured to close the bottom of the positioning hole 3b.

[0013] In addition, the knockout pin 5 is configured to position the flange portion 12 of the joining member 10 in the positioning hole 3b in the expanded hole 3a of the receiving die 3, and to expose the convex portion 13 of the joining member 10 from the receiving die 3.

[0014] Furthermore, when the knockout pin 5 protrudes into the positioning hole 3b after the pressing die 4 is retracted, the shaft portion 11 of the joining member 10 located in the positioning hole 3b is removed from the receiving die 3 together with the joined member 20 to which it is integrally joined.

[0015] Next, as shown in FIG. 2, the press die 4 is configured to work-harden the low-hardness to-be-joined members 20 during molding, thereby increasing their hardness and pressing the protrusions 13 of the joining members 10, which have a high hardness, through the inner walls of the recesses 21.

[0016] The joining member 10 undergoes plastic deformation such that the upper end surfaces of its protrusions 13 extend in a direction intersecting the pressure direction, while the outer periphery of its upper end flattens outward to form an undercut portion 13a. Accordingly, the joined member 20 also undergoes plastic deformation, causing its excess material to wrap around the back surface 11 of the undercut portion 13a, and the joined member 20 is tightly attached to the entire surface of the undercut portion 13a. In this way, the joining member 10 and the joined member 20 are mechanically joined, thereby producing the negative-side external battery terminal 1 for a secondary battery shown in FIG. 4.

[0017] Furthermore, the receiving mold 3 does not restrain the upper side of the outer periphery of the workpiece 20, but restrains the lower side with the expanded hole 3a. As a result, a step 22 is formed on the outer periphery of the workpiece 20 that is not restrained.

[0018] 3, in the process of finishing the outer periphery of the workpiece 20 into the desired shape, the upper outer periphery of the workpiece 20 is constrained by a cylindrical press die 6, and a punch pin 7 that can be inserted into the press die 6 presses the upper surface of the workpiece 20. The inner periphery of the press die 6 is rectangular, and therefore the outer periphery of the workpiece 20 is also formed into a roughly rectangular shape, with each side being straight.

[0019] According to the above-described manufacturing method for a battery external terminal, during the plastic deformation process due to compression, the lower side of the outer periphery of the joined members 20 is constrained while the upper side is not constrained, thereby forming the outer periphery of the joined members 20 into a stepped shape, and therefore no burrs are generated here, making it possible to produce a high-quality negative electrode external terminal 1.

[0020] The specific configuration of each part of the present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the spirit of the present invention. For example, the outer shape of the workpiece 20 may be finished into a polygonal shape other than a square. [Explanation of symbols]

[0021] 1 External terminal for battery 3. Receiving type 3a Expanded hole 3b Positioning hole 4 Press mold 5 knockout pins 6 Cylindrical mold 7 punch pins 10 Joint material 11 Shaft 12 Collar 13 Convex part 13a Undercut section 20 Parts to be joined 21 Recess 22 Step section

Claims

1. A method for manufacturing an external terminal for a battery, comprising the steps of: fitting a convex portion of a metal joining member into a concave portion of a metal joined member; and compressing both members in a compressive direction, thereby flattening the outer periphery of the end face of the convex portion of the joining member outward to form an undercut portion, thereby integrally joining the two members; A method for manufacturing an external terminal for a battery, characterized in that the receiving mold, which supports the joining member and restrains the outer shape of the joined member that plastically deforms due to compression, molds the outer edge of the joined member into a stepped shape.

2. 2. The manufacturing method for a battery external terminal according to claim 1, wherein the receiving mold restrains the lower side of the outer periphery of the joined member while leaving the upper side unrestrained, thereby forming the outer periphery of the joined member into a stepped shape.

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