Terminal for ultrasonic junction and method for joining electric wire to terminal for ultrasonic junction

Abstract

To efficiently perform ultrasonic junction of conductors of an electric wire while maintaining flexibility against differences in electric wire size.SOLUTION: A terminal 1 for ultrasonic junction has a flat conductor junction surface 3A where a core wire Wa of an electric wire W is mounted and subjected to ultrasonic junction, and is provided with projection parts 10, 11 on the conductor junction surface 3A at positions corresponding to both width-directional ends and the width-directional center when viewed from above the mounted core wire Wa.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a terminal for ultrasonic bonding and a method for bonding an electric wire to the terminal for ultrasonic bonding. [Background technology]

[0002] Known examples of the technology for joining an electric wire conductor and a terminal by applying ultrasonic vibrations while applying pressure to the joining interface are described in Patent Documents 1 and 2. When joining by applying ultrasonic vibrations, it is important to increase the propagation efficiency of the ultrasonic vibrations to the joining interface.

[0003] Patent Document 1 describes an example in which the shape of the conductor joint of the terminal and the shape of the anvil directly below the terminal are set to conform to the cross-sectional shape of the conductor of the electric wire in order to increase the propagation efficiency of the ultrasonic vibration applied by the horn. However, this technology has low versatility because the shape of the conductor joint of the terminal and the shape of the anvil must be changed according to the size of the electric wire, i.e., the cross-sectional size of the conductor.

[0004] Also, Patent Document 2 describes an example in which a convex portion extending in the width direction of the core wire of the electric wire is provided on the conductor joint surface of the terminal, and the core wire of the electric wire is placed on the convex portion to increase the contact pressure between the terminal and the core wire and strengthen the joint mainly for the purpose of waterproofing. However, since this technology has a convex portion extending in the width direction of the core wire, there is a possibility that the core wire may collapse during the joining process, and pressure may not be applied efficiently.

[0005] Since the conductor of an electric wire is generally formed with a substantially circular cross section, when the conductor of the electric wire is placed on the flat conductor joining surface of the terminal and pressed with a horn, large pressure unevenness occurs in the width direction of the conductor, i.e., in the direction perpendicular to the longitudinal direction of the electric wire, in the early stage of joining. In other words, the height (thickness) of the conductor in the pressure direction is large at the center in the width direction, but the height (thickness) of the conductor in the pressure direction decreases toward both ends in the width direction.

[0006] For example, if the conductor of an electric wire is a core wire consisting of multiple strands bundled together, the center of the core wire in the width direction will have a large number of strands in the pressure direction, so the height (thickness) will be large, but the number of strands in the pressure direction will decrease toward both ends of the core wire in the width direction, so the height (thickness) may become smaller. In this case, when pressure is applied with a horn, the pressure will be large at the center of the core wire in the width direction, but the pressure will not be effective toward both ends of the core wire in the width direction, so it will become smaller. As a result, the pressure distribution will be extremely uneven in the early stages of joining, and it may take a long time to achieve a sufficient joining state over the entire conductor. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 5202083 [Patent Document 2] JP 2015-135742 A Summary of the Invention [Problem to be solved by the invention]

[0008] As described above, when ultrasonic bonding is performed by setting a conductor having a substantially circular cross section on the flat conductor bonding surface of a terminal, the bonding efficiency may be reduced due to a large bias in the pressure distribution in the initial stage of bonding. Also, when the conductor is a core wire consisting of a bundle of multiple wires, there is a problem of a decrease in bonding efficiency due to the collapse of the core wire during bonding.

[0009] The present invention has been made in consideration of the above-mentioned circumstances, and its object is to provide an ultrasonic bonding terminal and a method for bonding an electric wire to an ultrasonic bonding terminal that enable efficient ultrasonic bonding of the conductor of an electric wire while maintaining versatility for different electric wire sizes. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the ultrasonic bonding terminal according to the present invention has the following features. a flat conductor joining surface on which a conductor having a substantially circular cross section of an electric wire is placed and ultrasonically joined; a protrusion is provided on the conductor joining surface at a position corresponding to both ends in a width direction of the conductor to be placed as viewed from above; Terminal for ultrasonic bonding.

[0011] In order to achieve the above-mentioned object, the method for joining an electric wire to an ultrasonic joining terminal according to the present invention has the following features. The conductor of the electric wire is placed on the conductor joining surface of the ultrasonic joining terminal so that both ends in the width direction of the conductor are overlapped with the convex portion, and the ultrasonic joining terminal is set on the anvil of an ultrasonic welding device, and ultrasonic vibration is applied to the conductor while applying pressure to the conductor by the horn of the ultrasonic welding device, thereby joining the conductor to the conductor joining surface of the ultrasonic joining terminal. A method for joining an electric wire to an ultrasonic joining terminal. Effect of the Invention

[0012] According to the present invention, it is possible to efficiently ultrasonically join the conductor of an electric wire to a terminal while maintaining versatility for different electric wire sizes.

[0013] The present invention has been briefly described above. Furthermore, the details of the present invention will be further clarified by reading the following description of the embodiment of the present invention (hereinafter, referred to as "embodiment") with reference to the accompanying drawings. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is an external perspective view showing an example of an ultrasonic bonding terminal according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view seen from above showing a state in which a conductor of an electric wire is placed on a conductor joining surface of the terminal of FIG. [Diagram 3]FIG. 3 is a cross-sectional view taken along line AA in FIG. 1, showing the state before joining in which the terminal of the embodiment is placed on the anvil of an ultrasonic joining device, the conductor of the end of an electric wire is placed on the conductor joining surface of the terminal, and ultrasonic joining is about to be performed from above using a horn. [Figure 4] FIG. 4 is a cross-sectional view showing an initial state during ultrasonic bonding by applying downward pressure to the horn in FIG. [Diagram 5] FIG. 5 is a cross-sectional view of a state similar to that of FIG. 3 in which there is no protrusion, given as a comparative example for the embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view of a state similar to that of FIG. 4 in which there is no protrusion, given as a comparative example for the embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view taken along the line BB in FIG. 1, showing the state before joining in which the conductor of the end of an electric wire is placed on the conductor joining surface of the terminal in FIG. 1 and ultrasonic joining is about to be performed from above using a horn. [Figure 8] FIG. 8 is a cross-sectional view of a state similar to that of FIG. 7 in which there is no protrusion, given as a comparative example for the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The electric wire to be connected in this embodiment is, for example, a high-voltage electric wire. A well-known example of a high-voltage electric wire is a thick electric wire having a core wire (often a "stranded wire") formed by bundling a plurality of wires made of copper, aluminum, or an aluminum alloy into a substantially circular cross section. The concept of a substantially circular cross section includes polygons with pentagons or more sides.

[0016] Ultrasonic bonding (ultrasonic metal bonding) is a widely known method for connecting this type of electric wire to a terminal. In ultrasonic bonding, a terminal is placed on an anvil, the core wire (conductor) of the electric wire is placed on the terminal, and ultrasonic waves are applied to bond the terminal and core wire while applying pressure from above with a horn. By applying ultrasonic waves to the terminal and core wire, oxide films and deposits that exist between the strands and at the bonding interface between the strands and between the strands and the terminal are destroyed and dispersed, and the metals are strongly bonded together by plastic deformation, and a metallic bond (solid-state bonding) is established by the action of atomic forces.

[0017] This method is different from fusion joining, typified by resistance welding, in that the base metals are joined in a solid phase, so the temperature does not rise to the point where the metal melts, and joining can be done at a relatively low temperature. Therefore, it has the advantage of being able to reduce the effects of heat.

[0018] In order to efficiently join the conductor and terminal of an electric wire by ultrasonic bonding, it is important to transmit the ultrasonic vibration to the bonding interface with as little loss as possible. To achieve this, it is necessary to reduce the bias in the pressure distribution acting on the bonding interface and increase the surface pressure at the bonding interface over the entire area.

[0019] However, when the core wire is constructed by bundling multiple wires into an approximately circular cross section, when pressure is applied to the core wire of an electric wire placed on the flat conductor joining surface of the terminal using the horn of an ultrasonic joining device, large pressure unevenness is likely to occur in the width direction of the conductor, especially in the early stages of joining.

[0020] In other words, when viewed from above, the center of the core wire's width has a large number of wires in the pressure direction, so it has a large height (thickness), but as you move toward both ends of the core wire's width, the number of wires in the pressure direction decreases, so the height (thickness) decreases (see Figure 3 or Figure 5). Therefore, when pressure is applied with a horn, the pressure is large in the center of the core wire's width, but as you move toward both ends of the core wire's width, the pressure does not act effectively and becomes smaller. This causes extreme bias in the pressure distribution in the early stages of joining (see Figure 6), and it may take a long time to achieve a sufficient joining state over the entire conductor.

[0021] In order to solve this problem, in the ultrasonic bonding terminal of the present embodiment, a plurality of convex portions are provided on a flat conductor bonding surface on which the conductor of the electric wire is placed and ultrasonically bonded. Hereinafter, the present embodiment will be specifically described with reference to the drawings.

[0022] FIG. 1 is an external perspective view of an ultrasonic bonding terminal according to an embodiment, and FIG. 2 is a plan view seen from above showing a state in which a conductor of an electric wire is placed on a conductor bonding surface of the ultrasonic bonding terminal.

[0023] As shown in Figures 1 and 2, an ultrasonic bonding terminal 1 (hereinafter also simply referred to as "terminal") of this embodiment has an electrical contact portion 2 with a through hole 2a for bolt fastening, on the front side in the longitudinal direction of a flat, strip-shaped substrate 1A made of a conductive metal plate (with copper or copper alloy as a base material). The terminal 1 also has an electric wire connection portion 3 on the rear side in the longitudinal direction of the substrate 1A. Here, one side of the electric wire connection portion 3 (the upper surface in Figures 1 and 2) is used as a conductor bonding surface 3A to which a core wire (conductor) Wa of an electric wire W is bonded by ultrasonic bonding, and cylindrical protrusions 10, 11 are dispersedly provided protruding from this conductor bonding surface 3A.

[0024] Specifically, a total of four protrusions 10 are provided on the conductor joining surface 3A at positions corresponding to both ends in the width direction of the core wire Wa of the electric wire W to be placed as viewed from above. Also, one protrusion 11 is provided on the conductor joining surface 3A at a position corresponding to the center in the width direction of the core wire Wa of the electric wire W to be placed as viewed from above. A total of five protrusions 10, 11 are provided in a distributed manner at the five points of the "5" on a die. The core wire Wa of the electric wire W is arranged so that its longitudinal direction coincides with the length direction of the terminal 1.

[0025] Fig. 3 shows a state before joining in which a terminal 1 of the embodiment is placed on an anvil 51 of an ultrasonic joining device, a core wire Wa of an end of an electric wire W is placed on a conductor joining surface 3A of the terminal, and ultrasonic joining is about to be performed from above with a horn 52. Fig. 3 is a cross-sectional view taken along the line AA in Fig. 1. Fig. 4 is a cross-sectional view showing an initial state in the middle of performing ultrasonic joining by applying a downward pressure indicated by an arrow F to the horn 52 in Fig. 3.

[0026] As shown in the cross section in Fig. 3, the core wire Wa is a twisted wire formed by bundling a plurality of elemental wires Wa1 into a substantially circular cross section (hexagonal in the illustrated example), and the insulating coating is removed and exposed at the end of the electric wire W, and the twisted wires are untwisted at the exposed portion. The heights of the protrusions 10, 11 are all set to the same height and are set to be equal to or greater than the diameter of the elemental wires Wa1. The heights of the protrusions 10, 11 may be different, but it is preferable that the height of the protrusions 10 at both ends is set to be equal to or greater than the height of the central protrusion 11. These protrusions 10, 11 are formed simultaneously when the terminal 1 is pressed. The protrusions 10, 11 may be formed by a method other than pressing.

[0027] Fig. 5 and Fig. 6 are figures given as comparative examples of this embodiment, Fig. 5 is a cross-sectional view in a state similar to Fig. 3 when there is no protrusion, and Fig. 6 is a cross-sectional view in a state similar to Fig. 4 when there is no protrusion. Fig. 7 is a cross-sectional view taken along the line BB in Fig. 1, showing a state before joining in which the conductor of the end of an electric wire is placed on the conductor joining surface of the terminal of this embodiment and ultrasonic joining is about to be performed from above using a horn. Fig. 8 is a cross-sectional view in a state similar to Fig. 7 when there is no protrusion, given as a comparative example of this embodiment.

[0028] When connecting an electric wire W to the terminal 1 of this embodiment, as shown in Figs. 2 and 3, a core wire Wa having a substantially circular cross section exposed at the end of the electric wire W is placed on the conductor joining surface 3A of the terminal 1 so that both ends in the width direction of the core wire Wa are over the protruding portion 10. With the core wire Wa placed in this manner, the terminal 1 is set on the anvil 51 of an ultrasonic welding device. The electric wire connecting portion 3 is held down, for example, by the jaw 53 of the ultrasonic welding device. Then, in this state, the horn 52 of the ultrasonic joining device is lowered to apply ultrasonic vibration while applying a pressure (see arrow F in Fig. 4) to the core wire Wa. The vibration direction of the ultrasonic vibration is perpendicular to the pressure force. In this manner, the core wire Wa is solid-state joined to the conductor joining surface 3A of the terminal 1 by applying pressure and ultrasonic vibration.

[0029] Incidentally, when pressure is applied to the core wire Wa of the electric wire W placed on the flat conductor joining surface 3A of the terminal 1 by the horn 52 of the ultrasonic joining device, the core wire Wa is configured by bundling a plurality of element wires Wa1 into a substantially circular cross section, as shown in Figures 3 and 4. For this reason, particularly in the early stages of joining, there is a possibility that significant pressure unevenness will occur in the width direction of the core wire Wa, i.e., in the direction perpendicular to the longitudinal direction of the electric wire.

[0030] That is, as shown in Fig. 5, when viewed from above, the center of the width of the core wire Wa has a large number of wires Wa1 in the pressure direction, so the height (thickness) is large, but as you move toward both ends of the core wire Wa in the width direction, the number of wires in the pressure direction decreases, so the height (thickness) decreases. Therefore, as shown in Fig. 6, when pressure is applied with the horn 52, the pressure (arrow f1) is large at the center of the width of the core wire Wa, but as you move toward both ends of the width of the core wire Wa, the pressure (arrow f2) does not act effectively and becomes smaller. Therefore, in the early stages of joining, the pressure distribution is extremely biased, and it may take a long time to achieve a sufficient joining state over the entire core wire Wa.

[0031] On the other hand, in the ultrasonic bonding terminal 1 of this embodiment, as shown in Fig. 1 to Fig. 4, the convex parts 10 are provided at positions corresponding to both ends in the width direction of the core wire Wa on the flat conductor bonding surface 3A. Therefore, by lifting both ends Ga in the width direction of the core wire Wa by the convex parts 10, it is possible to increase the pressure (arrow f2 in Fig. 4) applied to both ends in the width direction of the core wire Wa having a substantially circular cross section in the initial stage of ultrasonic bonding.

[0032] Therefore, the bias of pressure distribution between the core wire Wa (conductor) of the electric wire W and the terminal 1 can be reduced from the initial stage of joining, and ultrasonic vibration can be efficiently applied to the joining interface. The joining interface is the contact surface between the wire Wa1 and the wire Wa1, and the contact surface between the wire Wa1 and the terminal 1. As a result, it is possible to obtain sufficient joining performance over the entire width of the core wire Wa in a short time, and the joining efficiency is improved. In addition, the convex parts 10 at both ends prevent the core wire Wa from moving, making it possible to regulate the collapse of the core wire Wa, and thus to obtain good joining quality. In particular, since the height of the convex parts 10 is set to be equal to or greater than the diameter of the wire Wa1, the convex parts 10 can effectively correct the bias of pressure distribution at the initial stage of joining and suppress the collapse of the core wire Wa.

[0033] In addition, according to the ultrasonic bonding terminal 1 of this embodiment, the presence of the protrusion 11 located at the center of the width direction of the core wire Wa allows the pressure of the core wire Wa in that part to be increased from the early stage of bonding, and a starting point with a strong metal bond can be provided. That is, the wire Wa1 is pressed and crushed more strongly on the central protrusion 11 than other parts, so that the adjacent wires Wa1 and the wire Wa1 at the bottom are strongly attached to the conductor bonding surface 3A of the terminal 1, promoting solid-state bonding. Therefore, the bonding range can be expanded from the starting point, and bonding can be performed in a short time under low bonding conditions such as low pressure and low-power ultrasonic application.

[0034] Furthermore, as can be seen by comparing Figure 7 (this embodiment) with Figure 8 (comparison example), in addition to the convex portions 10 at both ends of the core wire Wa in the width direction, there is also a convex portion 11 at the center of the core wire Wa in the width direction, which makes it possible to effectively prevent the core wire Wa from losing its alignment, thereby further improving the joining efficiency.

[0035] Furthermore, in the ultrasonic bonding terminal 1 of this embodiment, since the protrusions 10, 11 are simply disposed on the flat conductor bonding surface 3A, it can be easily realized regardless of the wire size, and is highly versatile.

[0036] The material of the terminal 1 may be copper or a copper alloy, or may be aluminum or an aluminum alloy, as long as it is a metal material having electrical conductivity. The presence or absence of plating and the type of plating are not limited. In terms of shape, the terminal 1 may have a conductor joint surface 3A, a coating crimping piece may be provided at the rear of the electric wire connection portion 3, and the electric contact portion 2 at the front end side may be male or female. The terminal 1 may have an exterior part such as a shrink tube, a resin material, a sheet, etc., attached in advance for the purpose of waterproofing or corrosion prevention, or the joint may be finally molded with resin.

[0037] The conductor of the electric wire W may be a single-core wire, a wire incorporating a braid, or a copper foil in an FPC (Flexible Printed Circuit) or an FFC (Flexible Flat Cable). The conductor of the electric wire W may be made of any material other than copper, aluminum, or an aluminum alloy.

[0038] In addition, in the above embodiment, the cylindrical protrusions 10, 11 are arranged in a dispersed manner, but the shape is not limited to a cylindrical shape, and the protrusions 10, 11 may extend continuously in the longitudinal direction of the core wire Wa.

[0039] Here, the ultrasonic bonding terminal and the method of bonding an electric wire to the ultrasonic bonding terminal according to the above-mentioned embodiment of the present invention will be briefly summarized and listed in the following [1] to [5]. [1] A flat conductor joining surface (3A) on which the conductor (core wire Wa) of the electric wire (W) is placed and ultrasonically joined, The conductor joint surface (3A) is provided with protrusions (10) at positions corresponding to both ends in the width direction of the conductor (core wire Wa) when viewed from above. Terminal for ultrasonic bonding (1).

[0040] According to the above-mentioned configuration [1], since the convex parts (10) are provided at positions corresponding to both ends of the width direction of the conductor (core wire Wa) on the flat conductor joining surface (3A), the pressure applied to both ends of the width direction of the conductor (core wire Wa) can be increased in the early stage of ultrasonic joining. Therefore, the bias of the pressure distribution between the conductor (core wire Wa) of the electric wire and the terminal (1) can be reduced from the early stage of joining, and ultrasonic vibration can be efficiently applied to the joining interface. As a result, it is possible to obtain sufficient joining performance over the entire width direction of the conductor (core wire Wa) in a short time, and the joining efficiency can be improved. In addition, when the conductor (core wire Wa) is a core wire consisting of a bundle of multiple wires, the convex parts (10) at both ends can restrict the collapse of the core wire, and good joining quality can be obtained. In addition, by adjusting the position and size of the convex parts (10) arranged on the flat conductor joining surface (3A), it is possible to accommodate multiple electric wire sizes without changing the shape of the anvil, and therefore it is also excellent in versatility.

[0041] [2] The conductor (core wire Wa) is a core wire (Wa) formed by bundling a plurality of wires (Wa1) into a substantially circular cross section, The convex portions (10) are provided at positions on the conductor joining surface (3A) corresponding to both ends in the width direction of the core wire (Wa) to be placed as viewed from above. The ultrasonic bonding terminal (1) described in [1] above.

[0042] According to the above configuration [2], the presence of the convex portions (10) provided at positions corresponding to both ends of the core wire (Wa) in the width direction can suppress movement of the core wire (Wa) during ultrasonic joining, thereby suppressing the core wire (Wa) from coming apart, which is a challenge when joining an electric wire (W), and enabling efficient joining.

[0043] [3] The height of the protrusion (10) is equal to or greater than the diameter of the wire (Wa1), The ultrasonic bonding terminal (1) according to the above [2].

[0044] According to the above configuration [3], the convex portion (10) can effectively correct the bias in pressure distribution in the initial stage of joining and suppress the collapse of the core wire (Wa).

[0045] [4] A protrusion (11) is further provided on the conductor joining surface (3A) at a position corresponding to the widthwise center of the conductor (core wire Wa) when viewed from above. The ultrasonic bonding terminal (1) according to any one of the above [1] to [3].

[0046] According to the above configuration [4], the presence of the convex portion (11) located at the center in the width direction of the conductor (core wire Wa) makes it possible to increase the pressure on the conductor at that portion from the early stage of joining, and to provide a starting point with a strong metal joint. Therefore, the joining range can be expanded from the starting point, and joining can be performed in a short time under low joining conditions (low pressure or low-power ultrasonic application). In addition, when the conductor is a core wire (Wa) formed by bundling multiple strands (Wa1), the presence of the convex portion (11) at the center in the width direction of the core wire (Wa) makes it possible to effectively suppress the loss of alignment of the core wire (Wa), and further improve joining efficiency.

[0047] [5] A conductor (core wire Wa) of the electric wire (W) is placed on the conductor joining surface (3A) of the ultrasonic joining terminal (1) described in any one of [1] to [4] above, so that both widthwise ends of the conductor (core wire Wa) overlap the convex portion (10), and the ultrasonic joining terminal (1) is set on an anvil (51) of an ultrasonic welding device. In this state, ultrasonic vibration is applied to the conductor (core wire Wa) while applying pressure from a horn (52) of the ultrasonic welding device, thereby joining the conductor (core wire Wa) to the conductor joining surface (3A) of the ultrasonic joining terminal (1). A method for joining an electric wire (W) to an ultrasonic joining terminal (1).

[0048] In the joining method of [5] above, the conductor (core wire Wa) of the electric wire (W) is placed on the terminal (1) so that both ends of the conductor (core wire Wa) in the width direction are placed on the convex parts (10) on the flat conductor joining surface (3A). This reduces the bias in the pressure distribution between the conductor (core wire Wa) of the electric wire (W) and the terminal (1) during ultrasonic joining from the early stage of joining, and makes it possible to efficiently apply ultrasonic vibration to the joining interface. In addition, when the conductor is a core wire (Wa) formed by bundling a plurality of strands (Wa1), the presence of the convex parts (10) on both ends makes it possible to restrict the collapse of the core wire (Wa). As a result, it becomes possible to obtain sufficient joining performance over the entire width direction of the conductor (core wire Wa) in a short time, and to improve joining efficiency. In addition, by adjusting the position and size of the convex parts (10) on the flat conductor joining surface (3A), it is possible to accommodate a plurality of electric wire sizes without changing the shape of the anvil, and therefore it is also highly versatile. [Explanation of symbols]

[0049] 1 Terminal for ultrasonic bonding 3A Conductor interface 10, 11 Convex part W electric wire Wa Core wire (conductor) Wa1 wire 51 Anvil 52 Horn

Claims

1. a flat conductor joining surface on which the conductor of the electric wire is placed and ultrasonically joined; a protrusion is provided on the conductor joining surface at a position corresponding to both ends in a width direction of the conductor to be placed as viewed from above; Terminal for ultrasonic bonding.

2. The conductor is a core wire formed by bundling a plurality of wires into a substantially circular cross section, the protrusions are provided at positions on the conductor joining surface corresponding to both ends in a width direction of the core wire when viewed from above, The ultrasonic bonding terminal according to claim 1 .

3. The height of the protrusion is equal to or greater than the diameter of the wire. The ultrasonic bonding terminal according to claim 2 .

4. a protrusion is further provided on the conductor joining surface at a position corresponding to the center in the width direction as viewed from above of the conductor to be placed; The ultrasonic bonding terminal according to claim 1 .

5. The conductor of the electric wire is placed on the conductor joining surface of the ultrasonic bonding terminal according to any one of claims 1 to 4 so that both ends in the width direction of the conductor are overlapped with the convex portion, and the ultrasonic bonding terminal is set on an anvil of an ultrasonic welding device. In this state, ultrasonic vibration is applied to the conductor while applying a pressure force by a horn of the ultrasonic welding device to the conductor, thereby joining the conductor to the conductor joining surface of the ultrasonic bonding terminal. A method for joining an electric wire to an ultrasonic joining terminal.

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