Conductor bonding structure and ultrasonic conductor bonding method

Abstract

The joining structure is formed by ultrasonically joining conductors of a plurality of electric wires to each other. In the conductors, a conductor (5a) that is relatively difficult to deform and a conductor (5b) that is relatively easy to deform are mixed. That is, two or more types of electric wires comprising conductors made of different materials are mixed. When viewed from the axial direction of the electric wire, the arrangement of the conductors (5a, 5b) made of different materials is substantially linear symmetric with respect to the center line (A) in the width direction, where the ultrasonic bonding direction is the vertical direction of the conductor bonding portion and the direction orthogonal to the vertical direction is the width direction of the conductor bonding portion.

Description

Technical Field

[0001] The present invention relates to a conductor joining structure in which conductors of a plurality of electric wires are ultrasonically joined to each other and a conductor ultrasonic joining method. Background Art

[0002] Wiring harnesses used in automobiles and the like are used by joining a plurality of electric wires. As a method for joining such electric wires, for example, there is a method in which the insulation coatings of a plurality of insulated electric wires are stripped of a predetermined length to expose the conductors, the exposed conductors are twisted together in the same direction, and the twisted portions are welded and connected by ultrasonic welding (for example, Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-322544 Summary of the invention

[0006] Problems to be solved by the invention

[0007] On the other hand, sometimes wires made of different materials are joined instead of just wires made of the same material, and in such a case, sufficient joining strength may not be ensured.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a conductor joining structure and a conductor ultrasonic joining method capable of ultrasonically joining conducting wires made of different materials with high joining strength.

[0009] Solutions to Solve Problems

[0010] In order to achieve the aforementioned objectives, the first invention is a conductor joining structure, which is a conductor joining structure formed by ultrasonically joining the conductors of multiple electric wires. The conductor joining structure is characterized in that two or more electric wires composed of conductors of different materials are mixed together, and when observed from the axial direction of the electric wires, when the ultrasonic joining direction is taken as the up and down direction of the conductor joining part, and the direction orthogonal to the up and down direction is taken as the width direction of the conductor joining part, the arrangement of the electric wires composed of different materials is roughly line symmetrical with respect to the center line in the width direction, and with respect to at least a part of the center line, two or more electric wires are mixed together in the width direction of the conductor joining part.

[0011] Preferably, at least one of the electric wires is separated into a plurality of locations when viewed in the axial direction of the electric wire.

[0012] At least one of the electric wires may be separated in a vertical direction of the conductor joint portion when viewed in the axial direction of the electric wire.

[0013] The electric wire composed of a relatively deformable conductor may be arranged between the electric wires composed of a relatively non-deformable conductor.

[0014] The conductor that is relatively less likely to deform may be a conductor whose main component is copper, and the conductor that is relatively more likely to deform may be a conductor whose main component is aluminum.

[0015] The conductor that is relatively hard to deform may be a conductor whose main component is relatively hard aluminum, and the conductor that is relatively easy to deform may be a conductor whose main component is relatively soft aluminum.

[0016] One type of the electric wire may be arranged at the center in the width direction when viewed from the axial direction of the electric wire.

[0017] According to the first invention, by arranging the electric wires made of different materials substantially line-symmetrically with respect to the center line in the width direction, a high joint strength can be obtained.

[0018] In particular, when viewed from the axial direction of the wires, at least one wire (not gathered together) is separated at a plurality of locations, thereby achieving a higher joint strength. For example, by separating one type of wire in the vertical direction of the conductor joint portion, different wires can be joined to each other with a higher strength in the vertical direction.

[0019] For example, compared with wires composed of relatively easy-to-deform conductors, the conductor surfaces of wires composed of relatively hard-to-deform conductors are not sufficiently deformed, and it is sometimes difficult to obtain a high bonding strength due to the influence of the oxide film on the surface. On the other hand, if the bonding energy of ultrasonic bonding is increased, it may become a major factor in the fixation of the mold and the conductor.

[0020] On the other hand, by arranging a relatively easily deformable conductor between relatively undeformable conductors, a higher joint strength can be obtained than when the electric wires are composed of relatively undeformable conductors.

[0021] For example, if conductors that are relatively easy to deform are concentrated on one side and conductors that are relatively difficult to deform are concentrated on the other side for bonding, at the initial stage of bonding, only the deformation of the conductors that are relatively easy to deform progresses, and the bonding of the conductors that are relatively difficult to deform does not progress. That is, bonding is performed only on one side of the wire assembly. In contrast, by dispersing the conductors that are relatively difficult to deform and the conductors that are relatively easy to deform, bonding can be performed as a whole of the wire assembly from the initial stage of bonding. Therefore, the deviation of the bonding strength is small, and stable strength can be ensured.

[0022] In addition, in particular, when a conductor mainly composed of aluminum and a conductor mainly composed of copper are combined, the conductor mainly composed of copper is relatively difficult to deform. In this way, when a conductor mainly composed of aluminum and a conductor mainly composed of copper are combined, the effect can be obtained more reliably.

[0023] Similarly, even when the same aluminum is used, the effect can be reliably obtained when a conductor mainly composed of hard aluminum and a conductor mainly composed of soft aluminum are combined.

[0024] The second invention is a method for ultrasonically joining conductors, which is a method for ultrasonically joining conductors of multiple electric wires. The method for ultrasonically joining conductors is characterized in that an anvil, a welding head arranged opposite to the anvil, and a pair of gathering pieces opposed to each other in a direction orthogonal to the opposing direction of the anvil and the welding head are used. When an assembly consisting of multiple conductors is clamped by the anvil, the welding head and the gathering pieces and pressurized while being vibrated in a direction approximately perpendicular to the axial direction of the electric wire, when observed from the axial direction of the electric wire, the arrangement of the electric wires composed of different materials is approximately linearly symmetrical with respect to a center line in the vibration direction, and with respect to at least a portion of the center line, two or more types of electric wires are mixed in the direction clamped by the pair of gathering pieces.

[0025] According to the second invention, by arranging the electric wires made of different materials substantially in pairs with respect to the center line in the width direction, it is possible to obtain a high joint strength.

[0026] Effects of the Invention

[0027] According to the present invention, it is possible to provide a conductor joining structure and a conductor ultrasonic joining method capable of ultrasonically joining conducting wires made of different materials with high joining strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 2 is a diagram showing a bonding structure 1 .

[0029] Figure 2 It is a figure which shows the joining method of the conductors 5a and 5b.

[0030] Figure 3 This is a diagram showing a state where the conductors 5a and 5b are joined.

[0031] Figure 4A It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0032] Figure 4B It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0033] Figure 4C It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0034] Figure 4D It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0035] Figure 5A It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0036] Figure 5B It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0037] Figure 5C It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0038] Figure 5D It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0039] Fig. 6A It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0040] Figure 6B It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0041] Figure 6C It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0042] Fig.6D It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0043] Fig. 7A It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0044] Figure 7B It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0045] Figure 7C It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0046] Fig.7D It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0047] Fig. 8A It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0048] Figure 8B It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0049] Figure 8C It is a figure which shows another arrangement|positioning of the conductors 5a and 5b.

[0050] Fig. 9A2 is a diagram showing another arrangement of the conductors 5 a , 5 b , and 5 c .

[0051] Fig. 9B 2 is a diagram showing another arrangement of the conductors 5 a , 5 b , and 5 c .

[0052] Fig. 9C 2 is a diagram showing another arrangement of the conductors 5 a , 5 b , and 5 c .

[0053] Fig.9D 2 is a diagram showing another arrangement of the conductors 5 a , 5 b , and 5 c .

[0054] Fig.10 It is a figure which shows the measurement result of the bonding strength.

[0055] Fig.11 It is a figure which shows the measurement result of the bonding strength. DETAILED DESCRIPTION

[0056] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1 1 is a schematic diagram showing a joint structure 1. The joint structure 1 is formed by ultrasonically joining the conductors 5 of a plurality of electric wires 3. The electric wires 3 are formed by covering the outer periphery of the conductors 5 with an insulating coating. At the end of the electric wire 3, the insulating coating is removed in a predetermined range to expose the conductors 5 inside.

[0057] The conductor 5 is formed by twisting a plurality of wires, for example. It should be noted that the conductor 5 may also be a single wire. In addition, among the plurality of conductors 5, there are a mixture of conductors that are relatively difficult to deform and conductors that are relatively easy to deform. That is, there are a mixture of two or more types of electric wires 3 composed of conductors of different materials, and the details will be described later.

[0058] The conductors 5 of the plurality of electric wires 3 are arranged in the same direction, and a conductor joint portion 7 is formed at the front end of the conductor 5 by ultrasonically joining the conductors 5. That is, the conductors 5 are integrated at the conductor joint portion 7. It should be noted that the directions of the electric wires 3 are not necessarily all in the same direction, but it is preferred that at least a portion of the electric wires 3 are arranged in the same direction. In the figure, there is no electric wire in front of the conductor joint portion 7, but there may be an electric wire.

[0059] Next, a method for ultrasonically joining the conductors 5 of the plurality of electric wires 3 using an ultrasonic joining device will be described. Figure 2 1 is a diagram showing an ultrasonic bonding device 9 for ultrasonically bonding conductors to each other. The ultrasonic bonding device 9 includes an anvil 15, a horn 11 disposed opposite to the anvil 15, and a pair of convergence members 17 opposed to each other in a direction orthogonal to the opposing direction of the anvil 15 and the horn 11. It should be noted that the illustration of a vibration source for imparting vibration to the horn 11 is omitted.

[0060] In this embodiment, the plurality of electric wires 3 include electric wires 3 composed of conductors 5a that are relatively difficult to deform and electric wires 3 composed of conductors 5b that are relatively easy to deform. It should be noted that the material that is not easy to deform is, for example, a material with a relatively high melting point, a material with a high elastic modulus, a material with a high hardness, and a material with a large tensile strength. In other words, it is a material that has a small amount of deformation when subjected to the same compressive force during ultrasonic bonding.

[0061] As described above, as the conductors 5a and 5b having different degrees of deformability, for example, the relatively hard-to-deform conductor 5a is a conductor mainly composed of copper, and the relatively easy-to-deform conductor 5b is a conductor mainly composed of aluminum.

[0062] Even if the conductors 5a and 5b are made of the same material system, for example, the relatively hard-to-deform conductor 5a may be a conductor mainly composed of relatively hard aluminum (aluminum alloy, etc.), and the relatively easy-to-deform conductor 5b may be a conductor mainly composed of relatively soft aluminum (pure aluminum, etc.). Furthermore, when the ease of deformation is changed by additives, for example, the amount of additives may be relatively increased for the relatively hard-to-deform conductor 5a.

[0063] In order to perform ultrasonic bonding, first, an assembly of the conductors 5a and 5b of the plurality of electric wires 3 is arranged between the anvil 15 and the welding head 11 which are opposed to each other in the vertical direction. In addition, a gathering piece 17 is arranged on both sides of the assembly of the conductors 5a and 5b. That is, the assembly of the conductors 5a and 5b is clamped by the anvil 15 and the welding head 11 in the vertical direction and by a pair of gathering pieces 17 in the width direction.

[0064] Here, when viewed from the axial direction of the electric wire 3, the ultrasonic bonding direction is set as the vertical direction of the conductor bonding portion ( Figure 2 The vertical direction of the conductor joint is defined as the vertical direction of the conductor joint, and the direction perpendicular to it is defined as the width direction of the conductor joint ( Figure 2 In the left-right direction), the conductors 5a and 5b made of different materials are arranged approximately line-symmetrically with respect to the center line A in the width direction.

[0065] It should be noted that the following drawings also include a case where the arrangement of the conductor 5a and the conductor 5b is reversed. Figure 2 Although an example is shown in which the conductor 5 b is arranged on the anvil 15 side and the conductor 5 a is arranged on the horn 11 side, the conductor 5 a may be arranged on the anvil 15 side and the conductor 5 b may be arranged on the horn 11 side.

[0066] Next, if Figure 3As shown, in a state where the width direction of the assembly is restricted by the gathering piece 17, the assembly is clamped from the top and bottom directions by the anvil 15 and the welding head 11 and pressurized (the direction of the arrow B in the figure), and at the same time, the welding head 11 imparts ultrasonic vibration to the assembly in a direction roughly perpendicular to the pressurization direction (the direction of the arrow B in the figure). That is, the direction of the ultrasonic vibration is the width direction of the assembly (the direction of the arrow C in the figure), the axial direction of the wire, etc. Therefore, when observed from the axial direction of the wire 3, the arrangement of the wire 3 composed of different materials is roughly line symmetrical with respect to the center line A in the vibration direction. Through the above, a conductor joint 7 formed by gathering and joining a plurality of conductors 5a, 5b can be formed. At this time, the surface pattern of the welding head 11 is transferred to the upper surface of the conductor joint 7, so the up and down direction and the left and right direction of the conductor joint 7 are determined.

[0067] It should be noted that, in the example shown in the figure, the upper surface of the anvil 15 is flat, but it can also be rounded on both sides. That is, in the conductor joint portion 7, the portion corresponding to the angle between the gathering piece 17 and the anvil 15 can also be rounded. In addition, the lower surface on the welding head side is also flat, but it can also be rounded on both sides.

[0068] In summary, according to this embodiment, when a plurality of conductors 5a, 5b are assembled to form a conductor joint 7, a higher joint strength can be obtained by arranging the relatively non-deformable conductor 5a and the relatively deformable conductor 5b in a symmetrical manner relative to the center line A in the width direction (ultrasonic vibration direction).

[0069] It should be noted that such a symmetrical configuration is not limited to Figure 2 For example, Figure 4A to Figure 4D The left figure shows another arrangement of the conductors 5a and 5b, and the right figure shows the conductor joint 7 after welding (the same applies to the following figures). It should be noted that, as described above, the arrangement of the conductors 5a and 5b is the same even if they are swapped.

[0070] Figure 4A 1 is a diagram showing a state where the conductors 5a are arranged on both sides in the width direction and the conductor 5b is arranged between them. In this way, the conductors 5a and 5b may be separated in the left-right direction instead of being gathered in the up-down direction. It should be noted that in this case, the four conductors 5a are divided into two parts. That is, when viewed from the axial direction of the electric wire 3, at least one electric wire is not gathered together but is separated in multiple locations.

[0071] When the same type of conductors 5a and 5b are assembled and completely separated and arranged in two areas, there is a possibility that the deformation of the area where the relatively easy-to-deform conductor is arranged will advance first, and the bonding of the relatively hard-to-deform conductor may not be fully performed. In contrast, by arranging at least one of the conductors 5a and 5b in a manner of being divided into a plurality of areas, bonding deviation can be suppressed. That is, when arranging the two types of conductors 5a and 5b, they are arranged in a manner of being divided into three or more areas of the conductors 5a and 5b, so that the bonding strength can be stabilized.

[0072] It should be noted that it is more preferable to arrange the electric wire 3 composed of the relatively easy-to-deform conductor 5b between the electric wires 3 composed of the conductor 5a so that the relatively hard-to-deform conductor 5a is not adjacent. For example, since the relatively hard-to-deform conductors 5a are less deformed, the surface oxide may not be fully destroyed and the bonding strength may vary. In contrast, by arranging the electric wire 3 composed of the relatively easy-to-deform conductor 5b between the electric wires 3 composed of the relatively hard-to-deform conductor 5a, the bonding length of the conductors 5a can be shortened and the bonding length of the conductors 5a and 5b can be increased compared to the case where the conductors 5a are gathered in one place. Therefore, the bonding strength can be stabilized.

[0073] It should be noted that if Figure 4B As shown in the figure, it is more effective if all the conductors 5a and 5b are arranged in an alternating manner. That is, when viewed from the axial direction of the wire, at least one wire 3 is separated in the vertical direction of the conductor joint 7, and the conductors 5a and 5b of the same type are arranged in a manner not arranged in the vertical direction or the left and right direction, thereby further stabilizing the joint strength.

[0074] In addition, if Figure 4C As shown in FIG. 1 , when the number of conductors 5a and 5b is different, the conductors 5a having the smaller number are arranged in a dispersed manner without being arranged in a row, thereby obtaining the same effect. Figure 4D As shown, the separated conductor 5a may also be arranged on the anvil side instead of the welding head side.

[0075] In addition, if Figure 5A As shown in FIG. 1 , the number of conductors in the vertical direction and the width direction may be the same. That is, the cross-sectional shape of the conductor joint portion may be roughly square. In this case, it is preferred to separate at least one of the conductors 5a and 5b in multiple regions rather than gather the conductors 5a and 5b in one place. In this case, the conductors 5a and 5b may be separated in the vertical direction or in the width direction. Figure 5B As shown, the conductors 5a and 5b are separated to the left and right.

[0076] It should be noted that it is also possible to Figure 5C , Figure 5D Instead of arranging the conductors 5a and 5b in a row, the conductors 5a and 5b are arranged in a T shape or an inverted T shape as shown. In addition, the conductors 5a and 5b separated into a plurality of conductors may be separated into different numbers. For example, Fig. 6A , Figure 6B As shown, when the conductor 5a is separated into two parts, one part can be separated into three parts and the other part can be separated into one part.

[0077] It should be noted that if Figure 6C , Fig.6D In this case, by arranging the conductor 5b in a row between the upper and lower separated conductors 5a, the conductors 5a are not arranged in a row in the inclined direction, so the conductors 5a will not contact each other when joined, thereby enabling the conductors 5a and 5b to be reliably joined.

[0078] In addition, if Fig. 7A As shown in FIG. 1 , the same effect can be obtained even if the conductor 5a is separated at four corners. Figure 7B As shown in FIG. 1 , if the conductors 5a and 5b are arranged in a staggered manner, the conductors 5a and 5b can be separated individually. Figure 7C , Fig.7D As shown, one conductor 5 a (for example, a conductor that is relatively hard to deform) may be arranged only in the upper layer (on the bonding head 11 side) and the conductors 5 a may be arranged so as not to be adjacent to each other.

[0079] In addition, the sizes of the conductors 5a and 5b may also be different. For example, in the case of a relatively small conductor 5a, the conductors 5a and 5b may be different. Fig. 8A As shown, the conductor 5a is arranged at the center of the conductor 5b, or as shown Figure 8B The conductor 5a is arranged above the conductor 5b as shown in FIG. That is, for example, the conductor 5a which is relatively hard to be deformed may be arranged so as not to be exposed to the outer periphery and to be covered by other conductors 5b from the entire periphery, or the conductor 5a may be arranged so as to be exposed on the welding head side. In addition, when there are multiple conductors 5a, Figure 8C As shown in FIG. 1 , the conductor 5a is arranged above, below and in the center of the conductor 5b. In either case, the conductor 5a may be arranged between the conductors 5b in a state where the conductors 5b are aligned.

[0080] It should be noted that the number and arrangement of the wires are not limited to the above-mentioned examples. In addition, in the above-mentioned description, an example of forming the conductor joint 7 by combining two conductors 5a and 5b of different materials is described, but for example, Figure 9A to Figure 9DAs shown in the figure, conductors 5a, 5b, and 5c composed of three or more materials are mixed. In this case, by arranging the conductors of materials with different deformation easiness in a symmetrical manner with respect to the center line in the width direction (ultrasonic vibration direction), a high bonding strength can also be obtained. It should be noted that in this case, it is preferred to arrange the conductors that are least likely to deform separately in multiple locations.

[0081] In addition, it is preferable that two or more types of electric wires are mixed in at least a portion of the center line relative to the width direction (the direction sandwiched by the pair of gathering members) of the conductor joint portion 7. Figure 2 , Figure 5A As shown, when the various types of wires are arranged in a row (or multiple rows) in the entire width direction, the interfaces between them are linear with respect to the width direction, and the relatively soft material becomes soft first, and sometimes the bonding strength at the interface between different types of wires cannot be guaranteed. In particular, when the types of wires are aligned parallel to the vibration direction of the welding head 11 (that is, the width direction of the wire joint), the vibration during ultrasonic welding, especially in the horizontal direction, is unlikely to contribute to the improvement of the bonding strength. Therefore, by arranging the wires in a manner that multiple types of wires are mixed in the width direction in at least a portion of the conductor joint 7 in the up-down direction, the bonding strength at the interface between different types of wires can be ensured.

[0082] Example

[0083] The conductor configuration was changed and the bonding strength was evaluated. The conductors were arranged in each configuration and ultrasonically bonded within a length range of 10 mm. For the bonding structure, one of the wires was pulled in a 180-degree direction at 100 mm / min while the wires were fixed, and the maximum load when the conductor bonded part was torn was taken as the bonding strength. The results were reported in Fig.10 , Fig.11 Shown in.

[0084] It should be noted that the copper wire of Examples 1, 3 and Comparative Examples 1, 3, and 7 in the figure is a tough copper wire with a nominal cross-sectional area of ​​0.35 sq, the small-diameter copper wire of Examples 4, 5 and Comparative Examples 4, 5 is a Cu alloy wire containing Sn0.7 mass% with a nominal cross-sectional area of ​​0.13 sq, the soft aluminum wire is an aluminum alloy (A1070) wire with a nominal cross-sectional area of ​​0.75 sq, and the hard aluminum wire is an A6061 aluminum alloy wire with a nominal cross-sectional area of ​​0.5 sq.

[0085] like Fig.10 , Fig.11As shown, Examples 1 to 7, which are symmetrically arranged in the width direction, can obtain higher bonding strength than Comparative Examples 1 to 6, which are asymmetrical in the left and right directions. It should be noted that, although the details are omitted, compared with the comparative examples, Figure 2 4 to 9 are all high in bonding strength, and in particular, as in Examples 1 to 6, by separating and arranging one conductor A (a harder conductor) in a non-adjacent manner up, down, left, and right, a higher bonding strength can be obtained.

[0086] The embodiments of the present invention are described above with reference to the accompanying drawings, but the technical scope of the present invention is not limited by the aforementioned embodiments. Obviously, those skilled in the art can think of various changes or modifications within the scope of the technical ideas recorded in the technical solution, and can understand that these changes and modifications certainly also belong to the technical scope of the present invention.

[0087] For example, a relatively hard conductor or a relatively soft conductor may be disposed in at least a portion of the mating portion of the mold (between the anvil 15 and the gathering piece 17 , between the welding head 11 and the gathering piece 17 ).

[0088] Description of Reference Numerals

[0089] 1………Joint structure

[0090] 3. Electrical wires

[0091] 5, 5a, 5b, 5c………Conductors

[0092] 7...Conductor joint

[0093] 9……Ultrasonic bonding device

[0094] 11...Welding head

[0095] 15………Anvil

[0096] 17…………gathering pieces.

Claims

1. A conductor joint structure, wherein the conductors of a plurality of electric wires are ultrasonically joined to each other, wherein the conductor joint structure is characterized in that: Two or more types of the electric wires composed of conductors of different materials are mixed. When viewed from the axial direction of the electric wire, the ultrasonic bonding direction is defined as the vertical direction of the conductor bonding portion, and the direction perpendicular to the vertical direction is defined as the width direction of the conductor bonding portion. The electric wires made of different materials are arranged approximately line-symmetrically with respect to the center line in the width direction. With respect to at least a portion of the center line, two or more types of electric wires are mixed in a width direction of the conductor joint portion.

2. The conductor bonding structure according to claim 1, It is characterized in that At least one of the electric wires is separated into a plurality of locations when viewed from the axial direction of the electric wire.

3. The conductor bonding structure according to claim 2, It is characterized in that At least one of the electric wires is separated in the vertical direction of the conductor joint portion when viewed in the axial direction of the electric wires.

4. The conductor joint structure according to claim 2 or 3, It is characterized in that The electric wire composed of a relatively deformable conductor is arranged between the electric wires composed of a relatively non-deformable conductor.

5. The conductor bonding structure according to claim 4, It is characterized in that A conductor that is relatively less likely to deform is a conductor whose main component is copper, and a conductor that is relatively easy to deform is a conductor whose main component is aluminum.

6. The conductor bonding structure according to claim 4, It is characterized in that The conductor that is relatively difficult to deform is a conductor whose main component is relatively hard aluminum, and the conductor that is relatively easy to deform is a conductor whose main component is relatively soft aluminum.

7. The conductor bonding structure according to claim 1, It is characterized in that When viewed from the axial direction of the electric wire, one of the electric wires is arranged at the center in the width direction.

8. A method for ultrasonically joining conductors, which is a method for ultrasonically joining conductors of a plurality of electric wires, wherein the method for ultrasonically joining conductors comprises: An anvil, a horn disposed opposite to the anvil, and a pair of gathering members opposed to each other in a direction orthogonal to the opposing direction of the anvil and the horn, When an assembly consisting of a plurality of conductors is clamped by the anvil, the welding head and the gathering piece and pressurized while being vibrated in a direction approximately perpendicular to the axial direction of the wire, when observed from the axial direction of the wire, the arrangement of the wires made of different materials is approximately linearly symmetrical with respect to a center line in the vibration direction, and with respect to at least a portion of the center line, two or more types of wires are mixed in the direction clamped by a pair of the gathering pieces.

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