Wire connection structure

Abstract

To improve strength of a connection between a wire and a mating component in a wire connection structure.SOLUTION: A wire connection structure 10 includes a wire 30, in which multiple core wires 30A are covered with an insulation sheath 30B, and a mating component 20 connected to the wire 30. The wire 30 has a core wire exposed part 31 in which the multiple core wires 30A are exposed from the insulation sheath 30B. The core wire exposed part 31 has a welding portion 33 that is joined to the mating component 20 by ultrasonic welding and a tip part 32 that is arranged at one end of a first direction D1 and is not joined to the mating component 20. The welding part 33 is arranged in a row on the other side of the first direction D1 to the tip part 32. The multiple core wires 30A arranged on the welding part 33 are arranged in a single line in a second direction D2, which is perpendicular to the first direction D1, and also extend along the first direction D1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a wire connection structure. [Background technology]

[0002] Conventionally, a power storage device described in JP 2016-48635 A (Patent Document 1 below) is known. The power storage device described in Patent Document 1 includes a power storage element, a bus bar connected to an external terminal of the power storage element, and a conductive wire electrically connected to the bus bar. Patent Document 1 describes, for example, that the bus bar and the conductive wire are electrically connected by joining a core wire exposed at a tip of the conductive wire to a connected portion of the bus bar by ultrasonic welding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-48635 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above configuration, for example, if the metal constituting the bus bar is different from the metal constituting the core wire of the conductive wire, it may become difficult to ensure the strength of the joint between the conductive wire and the bus bar. [Means for solving the problem]

[0005] The electric wire connection structure disclosed herein includes an electric wire having a plurality of core wires covered with an insulating coating, and a mating member to be connected to the electric wire, the electric wire having an exposed core wire portion in which the plurality of core wires are exposed from the insulating coating, the exposed core wire portion including a welded portion joined to the mating member by ultrasonic welding, and a tip portion arranged at an end on one side in a first direction and not joined to the mating member, the welded portion being arranged in series with the tip portion on the other side in the first direction, and the plurality of core wires arranged at the welded portion being arranged in a row side by side in a second direction perpendicular to the first direction and extending along the first direction. Effect of the Invention

[0006] According to the present disclosure, it is possible to improve the strength of the joint between the electric wire and the mating member in an electric wire connection structure. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of an electric wire connection structure according to an embodiment. [Diagram 2] FIG. 2 is a plan view of the electric wire connection structure shown in FIG. [Diagram 3] FIG. 3 is a cross-sectional view taken along line AA of FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line BB of FIG. [Diagram 5] FIG. 5 is a plan view of the electric wire. [Figure 6] FIG. 6 is a plan view of the electric wire in a state where the multiple core wires are untwisted. [Figure 7] FIG. 7 is an explanatory diagram for explaining the welding process of the electric wires. [Figure 8] FIG. 8 is a cross-sectional view taken along line CC of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described. [1] The electric wire connection structure disclosed herein comprises an electric wire having a plurality of core wires covered with an insulating coating, and a mating member to be connected to the electric wire, the electric wire having an exposed core portion in which the plurality of core wires are exposed from the insulating coating, the exposed core portion comprising a weld portion joined to the mating member by ultrasonic welding, and a tip portion arranged at an end on one side in a first direction and not joined to the mating member, the weld portion being arranged in series with the tip portion on the other side in the first direction, and the plurality of core wires arranged at the weld portion being arranged side by side in a row in a second direction perpendicular to the first direction and extending along the first direction.

[0009] With this configuration, the area of ​​the joint between the welded portion and the mating member can be increased, improving the strength of the joint between the welded portion and the mating member. Therefore, even if the core wire and the mating member are made of different types of metal, for example, the strength of the joint between the core wire and the mating member can be easily ensured. In addition, since the tip portion is not joined to the mating member, it is possible to prevent the tip of the core wire from sinking into the mating member. Therefore, it is possible to prevent burrs from occurring around the tip of the core wire on the mating member. In this specification, "ultrasonic welding" is also intended to include ultrasonic welding.

[0010] [2] In the above item [1], it is preferable that the multiple core wires arranged at the tip portion extend along a surface of the counterpart member.

[0011] According to this configuration, the tip portion is used to position the electric wire relative to the mating member, making it easier to control the arrangement of the multiple core wires in the welded portion. Also, the tip portion is less likely to come into contact with surrounding objects.

[0012] [3] In the above item [2], it is preferable that the multiple core wires arranged at the tip portion are arranged side by side in the second direction and extend in the first direction.

[0013] With this configuration, stress is less likely to be applied to each core wire at the tip portion compared to a case in which the core wires at the tip portion extend in different directions and are arranged separately, and therefore stress is less likely to be applied to each core wire at the welded portion connected to each core wire at the tip portion, making it easier to maintain the electrical connection between the electric wire and the mating member.

[0014] [4] In any one of the above items [1] to [3], it is preferable that the dimension of the tip portion in the first direction is set smaller than the dimension of the welded portion in the first direction.

[0015] With this configuration, the dimension of the welded portion in the first direction can be increased in the core wire exposed portion, thereby increasing the area of ​​the joint between the welded portion and the counterpart member and further improving the strength of the joint.

[0016] [Details of the embodiment of the present disclosure] The following describes embodiments of the present disclosure. The present disclosure is not limited to these examples, but is shown by the claims, and is intended to include all modifications within the meaning and scope of the claims. In each drawing, for convenience of explanation, some of the configuration may be exaggerated or simplified. In addition, the dimensional ratio of each part may differ in each drawing. In this specification, "orthogonal" and "parallel" do not only mean strictly orthogonal or parallel, but also include roughly orthogonal and parallel within the range in which the action and effect of this embodiment can be achieved.

[0017] In addition, "facing" in this specification refers to surfaces or members facing each other, and includes not only cases where they are completely facing each other, but also cases where they are partially facing each other. In addition, "facing" in this specification includes both cases where a member other than the two parts is interposed between the two parts, and cases where nothing is interposed between the two parts.

[0018] In each drawing, three mutually perpendicular directions are shown as a first direction D1, a second direction D2, and a third direction D3. That is, the first direction D1 and the second direction D2 are mutually perpendicular, the first direction D1 and the third direction D3 are mutually perpendicular, and the second direction D2 and the third direction D3 are mutually perpendicular. By showing arrows on both sides of the solid line indicating each direction, not only the direction of the arrow on the side with the symbol, but also the direction of the arrow on the side without the symbol is considered to indicate the corresponding direction.

[0019] <Embodiment> An embodiment of the present disclosure will be described with reference to Figures 1 to 8. Note that, for multiple identical members, reference numerals may be given to only some of the members, and the reference numerals of the other members may be omitted.

[0020] (Electric wire connection structure 10, counterpart member 20) As shown in Figs. 1 and 2, the electric wire connection structure 10 is a connection structure between a mating member 20 and an electric wire 30. The mating member 20 is made of a conductive metal. The mating member 20 may be a bus bar connected to an electrode terminal of an energy storage element. The mating member 20 is, for example, plate-shaped. The mating member 20 has a surface 21 to which the electric wire 30 is connected. The surface 21 is disposed perpendicular to the third direction D3 and connected to the electric wire 30. The electric wire 30 is connected to the mating member 20 from one side (hereinafter referred to as the upper side) of the third direction D3.

[0021] (Wire 30) The electric wire 30 has a plurality of core wires 30A and an insulating coating 30B that covers the plurality of core wires 30A from the outside. The core wire 30A is made of a conductive metal. The insulating coating 30B is made of an insulating synthetic resin. The electric wire 30 has an exposed core wire portion 31 where the insulating coating 30B has been removed to expose the plurality of core wires 30A. The exposed core wire portion 31 is disposed at one end of the electric wire 30 in the first direction D1 (the left end portion in FIG. 2).

[0022] The exposed core wire portion 31 extends in the first direction D1. The exposed core wire portion 31 includes a tip portion 32, a welded portion 33, and a base portion 34. The tip portion 32 is disposed at an end portion on one side of the exposed core wire portion 31 in the first direction D1. The tip portion 32 is a region between the tip of the exposed core wire portion 31 and the welded portion 33. The welded portion 33 is continuous with the tip portion 32 on the other side of the first direction D1. The base portion 34 is continuous with the welded portion 33 on the other side of the first direction D1. The base portion 34 is disposed at an end portion on the other side of the exposed core wire portion 31 in the first direction D1. The base portion 34 extends from an opening provided at an end portion on one side of the insulating coating 30B in the first direction D1. The multiple core wires 30A disposed at the base portion 34 are shaped to expand in the second direction D2 as they move toward one side of the first direction D1. The base portion 34 is generally fan-shaped in a plan view.

[0023] (Welded part 33) The welded portion 33 is a portion of the core wire exposed portion 31 that is ultrasonically welded to the surface 21 of the counterpart member 20. The welded portion 33 has a substantially rectangular shape in a plan view. That is, both end edges of the welded portion 33 in the second direction D2 are substantially parallel to each other. The multiple core wires 30A arranged in the welded portion 33 are arranged side by side in the second direction D2 and extend in the first direction D1.

[0024] FIG. 4 shows a cross section of the welded portion 33 cut at a cutting surface perpendicular to the first direction D1. Note that the tip portion 32 is omitted in FIG. 4. As shown in FIG. 4, the multiple core wires 30A of the welded portion 33 are arranged so as not to overlap each other in the third direction D3 (vertical direction). Due to the welding process for forming the welded portion 33, each core wire 30A of the welded portion 33 has a flat shape in the vertical direction. In addition, the surface 21 of the counter member 20 connected to the welded portion 33 is deformed, and the lower parts of the multiple core wires 30A are embedded in the counter member 20. Therefore, as shown in FIG. 3, the welded portion 33 is recessed downward compared to the tip portion 32 and the base portion 34. Note that in FIG. 3, only one core wire 30A of the multiple core wires 30A arranged in the base portion 34 is shown.

[0025] According to the above-mentioned configuration, it is possible to increase the area involved in welding between the welded portion 33 and the counterpart member 20. Therefore, the strength of the joint between the welded portion 33 and the counterpart member 20 can be improved.

[0026] On the other hand, for example, unlike this embodiment, if multiple core wires at the welded portion are not aligned in the second direction D2 but are arranged overlapping in the third direction D3, the area involved in welding between the welded portion and the opposing member becomes smaller compared to this embodiment, and it is difficult to ensure the strength of the joint.

[0027] It is generally known that when two metal members made of different metal types are ultrasonically welded, the joint strength per unit area is lower than when two metal members made of the same metal type are ultrasonically welded. However, in this embodiment, the area involved in welding between the welded portion 33 and the counterpart member 20 can be increased, so that even if the metal constituting the core wire 30A and the metal constituting the counterpart member 20 are different, the joint strength between the core wire 30A and the counterpart member 20 can be easily ensured.

[0028] 4, the multiple core wires 30A of the welded portion 33 are preferably arranged without any gaps in the second direction D2. That is, the multiple core wires 30A of the welded portion 33 are preferably connected to each other in the second direction D2 and formed into a substantially plate-like shape. This makes it difficult for the multiple core wires 30A of the welded portion 33 to peel off individually from the mating member 20.

[0029] (Tip 32) 1 and 2, the tip portion 32 is disposed at one end of the exposed core portion 31 in the first direction D1. The tip portion 32 is not joined to the mating member 20. The tip portion 32 can be used to position the electric wire 30 with respect to the mating member 20, as described later.

[0030] 3, the multiple core wires 30A arranged in the tip portion 32 extend along the surface 21. That is, the multiple core wires 30A in the tip portion 32 are not in a form that jumps up from the mating member 20. Therefore, when the electric wire connection structure 10 is handled, it is possible to prevent the core wires 30A in the tip portion 32 from coming into contact with surrounding structures. Therefore, it is possible to prevent the core wires 30A in the tip portion 32 from being cut and the welded portion 33 from being subjected to stress.

[0031] In this embodiment, as shown in Figs. 1 and 2, the multiple core wires 30A of the tip portion 32 are arranged side by side in the second direction D2 and extend in the first direction D1. In addition, it is preferable that the multiple core wires 30A of the tip portion 32 are arranged with as few gaps as possible in the second direction D2. According to this configuration, since each core wire 30A of the tip portion 32 is arranged adjacent to other core wires 30A, stress is unlikely to be applied individually to each core wire 30A of the tip portion 32. Therefore, breakage of each core wire 30A of the tip portion 32 can be suppressed. In addition, stress is unlikely to be applied to each core wire 30A of the welded portion 33A connected to each core wire 30A of the tip portion 32, and the electrical connection between the electric wire 30 and the counterpart member 20 is easily maintained.

[0032] On the other hand, for example, if the core wires at the tip portion extend in different directions and are arranged separately, stress is likely to be applied to each core wire at the tip portion individually, and therefore, compared to this embodiment, breakage of each core wire at the tip portion and peeling of each core wire at the welded portion are more likely to occur.

[0033] In this embodiment, as shown in FIG. 2, the dimension L1 of the tip portion 32 in the first direction D1 is set to be smaller than the dimension L2 of the welded portion 33 in the first direction D1. This allows the dimension L2 of the welded portion 33 in the first direction D1 to be large in the core wire exposed portion 31. This increases the area required for welding between the welded portion 33 and the counter member 20, and further improves the strength of the joint. In addition, by making the dimension L1 of the tip portion 32 in the first direction D1 the minimum necessary, it is possible to suppress the application of stress to the tip portion 32 from the outside. Therefore, it is possible to further suppress breakage of each core wire 30A of the tip portion 32 and peeling of each core wire 30A of the welded portion 33.

[0034] An example of a method for manufacturing the electric wire connection structure 10 will be briefly described below. First, a portion that will become the exposed core portion 31 is formed on the electric wire 30. As shown in FIG. 5, the insulating coating 30B of the electric wire 30 is peeled off to expose the multiple core wires 30A. The multiple core wires 30A may be twisted together. Next, as shown in FIG. 6, the multiple core wires 30A are untwisted to extend in approximately one direction. For example, the multiple core wires 30A can be held by a jig (not shown) from both sides in the radial direction of the electric wire 30 and the jig is slid in one direction to extend the multiple core wires 30A in approximately one direction.

[0035] 7, ultrasonic welding of the electric wire 30 is performed by an ultrasonic welding device 40. The ultrasonic welding device 40 includes a horn 41, an anvil 42, a positioning jig 43, and a fixing part (not shown). The horn 41 is disposed above the anvil 42. First, the mating member 20 is placed on the anvil 42, and the exposed core wire portion 31 is placed on the surface 21 of the mating member 20. The positioning jig 43 positions the ends (portions that will become the tip portions 32) of the multiple core wires 30A in the first direction D1 relative to the mating member 20. In addition, the end of the insulating coating 30B close to the exposed core wire portion 31 is fixed by the fixing part.

[0036] 8, the positioning jig 43 includes, for example, a first contact portion 43A contacting the core wire 30A from one side in the second direction D2, a second contact portion 43B contacting the core wire 30A from the other side in the second direction D2, a third contact portion 43C contacting the core wires 30A from the opposite side to the mating member 20 in the third direction D3, and an opposing surface 43D opposing the surface 21 of the mating member 20. The first contact portion 43A, the second contact portion 43B, and the third contact portion 43C are formed as inner surfaces of a recess recessed from the opposing surface 43D. The distance between the third contact portion 43C and the opposing surface 43D in the third direction D3 is approximately the same as the diameter of the electric wire 30. The distance between the first contact portion 43A and the second contact portion 43B in the second direction D2 is approximately equal to the length obtained by multiplying the diameter of the core wire 30A by the number of the core wires 30A. The positioning jig 43 may be composed of two members that regulate the positions of the multiple core wires 30A by approaching each other in the second direction D2.

[0037] 7, after the electric wire 30 is positioned relative to the counterpart member 20 by a positioning jig 43 and a fixing portion, a horn 41 is pressed from above against the portion of the core wires 30A that will become the welded portion 33. The horn 41 includes a vibrator (not shown) that generates ultrasonic vibrations, and is vibrated by this vibrator. With the horn 41 pressing the counterpart member 20 and the core wires 30A on the anvil 42, the horn 41 is ultrasonically vibrated, thereby welding the core wires 30A to the counterpart member 20 (welding process).

[0038] As described above, the positioning of the core wires 30A by the positioning jig 43 makes it possible to position the welded portion 33 relative to the mating member 20. In addition, it becomes easier to control the arrangement of the core wires 30A that become the welded portion 33. That is, in the welded portion 33, the core wires 30A can be aligned in the second direction D2 and extended in the first direction D1.

[0039] In the welding process, for example, it is preferable that the horn 41 vibrates along the extension direction (first direction D1) of the core wires 30A. This makes it easier to press the core wires 30A against the counterpart member 20. As a result, the core wires 30A are pressed against the counterpart member 20, making it easier to remove the oxide coating on the surface 21 of the counterpart member 20. This improves the strength of the joint between the welded portion 33 and the counterpart member 20. In addition, by arranging the vibration direction of the horn 41 and the extension direction of the core wires 30A parallel to each other, it is possible to prevent stress from acting on the core wires 30A from the horn 41 in a direction that cuts the core wires 30A, and thus to suppress breakage of the core wires 30A.

[0040] For example, unlike the present embodiment, when no tip portion is provided, the position of the end of one side of the multiple core wires in the first direction D1 at the welded portion may be significantly shifted, or the multiple core wires may spread in the second direction D2, which may result in a lower joint strength than the present embodiment. For example, when the multiple core wires spread in the second direction D2 at the welded portion, the multiple core wires spread radially, resulting in a state in which the vibration direction of the horn (first direction D1) and the extension direction of the multiple core wires intersect. This reduces the holding force of the multiple core wires by the horn, making it difficult to sufficiently remove the oxide film on the surface of the mating member. For this reason, the joint strength between the welded portion and the mating member is likely to decrease. In addition, when the vibration direction of the horn and the extension direction of the multiple core wires are arranged to intersect, stress acts from the horn on the core wires in a direction that cuts the core wires, making the core wires more likely to break. The strength of the joint is also reduced when the core wires are cut.

[0041] It is known that when the core wire 30A is made of copper and the counterpart member 20 is made of aluminum, when the core wire 30A is ultrasonically welded to the counterpart member 20, burrs are likely to occur on the counterpart member 20 due to the difference in hardness between copper and aluminum. However, according to the configuration of this embodiment, the area of ​​the weld between the welded portion 33 and the counterpart member 20 is increased, so that the stress acting on the counterpart member 20 during ultrasonic welding can be alleviated. In addition, since the tip portion 32 can position the welded portion 33, it is possible to prevent the multiple core wires 30A of the welded portion 33 from moving freely in the first direction D1. Therefore, it is possible to prevent the occurrence of burrs on the counterpart member 20. In addition, since the multiple core wires 30A are arranged in contact with each other in the second direction D2 and extend in the first direction D1, the welded portion 33 has a substantially plate-like shape. Therefore, even if burrs occur below the welded portion 33, the welded portion 33 functions as a lid for the burrs, so that it is possible to prevent the burrs from scattering.

[0042] (Effects of the embodiment) (1) The electric wire connection structure 10 according to the embodiment includes an electric wire 30 having multiple core wires 30A covered with an insulating coating 30B, and a mating member 20 to be connected to the electric wire 30. The electric wire 30 has an exposed core portion 31 at one end in a first direction D1 where the multiple core wires 30A are exposed from the insulating coating 30B. The exposed core portion 31 includes a welded portion 33 joined to the mating member 20 by ultrasonic welding, and a tip portion 32 arranged at the one end in the first direction D1 and not joined to the mating member 20. The welded portion 33 is arranged in series with the tip portion 32 on the other side of the first direction D1. The multiple core wires 30A arranged in the welded portion 33 are arranged in a row in a second direction D2 perpendicular to the first direction D1 and extend along the first direction D1.

[0043] With this configuration, the area of ​​the joint between the welded portion 33 and the counterpart member 20 is increased, and the strength of the joint between the welded portion 33 and the counterpart member 20 can be improved. Therefore, even if the core wire 30A and the counterpart member 20 are made of different types of metals, for example, the strength of the joint between the core wire 30A and the counterpart member 20 can be easily ensured. In addition, since the tip portion 32 is not joined to the counterpart member 20, the tip of the core wire 30A can be prevented from sinking into the counterpart member 20. Therefore, the occurrence of burrs around the tip of the core wire 30A in the counterpart member 20 can be prevented.

[0044] (2) In the embodiment, the multiple core wires 30A arranged in the tip portion 32 extend along the surface 21 of the counterpart member 20.

[0045] According to such a configuration, by using the tip portion 32 to position the electric wire 30 with respect to the counterpart member 20, it becomes easier to control the arrangement of the multiple core wires 30A at the welded portion 33. In addition, the tip portion 32 is less likely to come into contact with surrounding objects.

[0046] (3) In the embodiment, the multiple core wires 30A arranged in the tip portion 32 are arranged side by side in the second direction D2 and extend in the first direction D1.

[0047] With this configuration, stress is less likely to be applied to each core wire 30A of the tip portion 32 compared to a case in which the core wires of the tip portion extend in different directions and are arranged separately. Therefore, stress is less likely to be applied to each core wire 30A of the welded portion 33 connected to each core wire 30A of the tip portion 32, and the electrical connection between the electric wire 30 and the counterpart member 20 is more easily maintained.

[0048] (4) In the embodiment, the dimension L1 of the tip portion 32 in the first direction D1 is set to be smaller than the dimension L2 of the welded portion 33 in the first direction D1.

[0049] With this configuration, it is possible to increase the dimension L2 in the first direction D1 of the welded portion 33 in the core wire exposed portion 31. This increases the area involved in joining the welded portion 33 and the counterpart member 20, thereby further improving the strength of the joint.

[0050] (Other embodiments) The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0051] In the above embodiment, the upper surface of the welded portion 33 is generally smooth, but the upper surface of the welded portion may have an uneven structure. For example, the welded portion may be formed by a horn with a recess on its underside, and a protrusion corresponding to the recess may be formed on the upper portion of the welded portion.

[0052] In the above embodiment, the core wires 30A of the welded portion 33 are arranged side by side without any gaps in the second direction D2, but the core wires of the welded portion may have gaps in the second direction. The gaps are preferably small compared to the diameters of the core wires.

[0053] The multiple core wires in the tip portion may extend in a direction intersecting the first direction. The multiple core wires in the tip portion do not necessarily have to extend along the surface of the counterpart member. [Explanation of symbols]

[0054] 10: Wire connection structure 20: Counterpart 21: Surface 30: Electric wire 30A: Core wire 30B: Insulation coating 31: Exposed core 32: Tip 33: Welded parts 33A: Welded parts 34: Base 40: Ultrasonic welding equipment 41: Horn 42: Anvil 43: Positioning jig 43A: 1st contact part 43B: Second contact part 43C: 3rd contact part 43D: Counterface D1: 1st direction D2: Second direction D3: Third direction L1: Dimension of tip portion 32 in the first direction D1 L2: Dimension of the welded portion 33 in the first direction D1

Claims

1. An electric wire having a plurality of core wires covered with an insulating coating; A mating member to be connected to the electric wire, The electric wire has a core exposed portion where the plurality of core wires are exposed from the insulating coating, the exposed core portion includes a welded portion that is joined to the mating member by ultrasonic welding, and a tip portion that is disposed at an end portion on one side in a first direction and is not joined to the mating member, The welded portion is disposed adjacent to the other side of the tip portion in the first direction, an electric wire connection structure, in which the multiple core wires arranged at the welded portion are arranged in a row in a second direction perpendicular to the first direction and extend along the first direction.

2. The electric wire connection structure according to claim 1 , wherein the plurality of core wires arranged at the tip portion extend along a surface of the mating member.

3. The electric wire connection structure according to claim 2 , wherein the plurality of core wires arranged at the tip portion are arranged side by side in the second direction and extend in the first direction.

4. The electric wire connection structure according to claim 3 , wherein a dimension of the tip portion in the first direction is set smaller than a dimension of the welded portion in the first direction.

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