Carbon nanotube wire connection structure

Abstract

The present invention provides a carbon nanotube wire connection structure, which can connect the carbon nanotube wire to a connection object at a desired position by simple operation, and the connection portion between the carbon nanotube wire and the connection object has excellent electrical connectivity and mechanical connectivity. The carbon nanotube wire connection structure includes a carbon nanotube wire formed by twisting and bundling a carbon nanotube aggregate, a connection object to connect the carbon nanotube wire, a wire having higher solder wettability than the carbon nanotube wire, a through portion of the wire formed along a cross section having a component orthogonal to the length direction of the carbon nanotube wire, and solder connecting the carbon nanotube wire and the connection object, wherein the solder is impregnated into the through portion formed along the wire.

Description

Technical Field

[0001] The present invention relates to a connection structure, which is a connection structure of a carbon nanotube wire and a connection object to which the carbon nanotube wire is connected. Background Art

[0002] Carbon nanotubes (hereinafter sometimes referred to as CNTs) are raw materials with various properties and are expected to be used in many fields. CNTs are lightweight and have excellent electrical conductivity, thermal conductivity, mechanical strength and many other properties, so they are expected to be used as wires to replace metal wires, for example, as electric wires.

[0003] When carbon nanotubes are used as wires, the size of the carbon nanotube wires (hereinafter sometimes referred to as CNT wires) must be lengthened. However, lengthening the CNT wires requires high technology. As an existing CNT wire lengthening technology, it is proposed to connect the carbon nanotube wires to each other by winding the carbon nanotubes grown from each carbon nanotube wire around the corresponding connecting object side carbon nanotube wire and / or the grown carbon nanotube (Patent Document 1).

[0004] However, in Patent Document 1, in order to make carbon nanotubes grow from carbon nanotube wires, it is necessary to apply a catalyst solution to the parts where the carbon nanotube wires are connected to each other, so that the carbon nanotubes grow and entangle with the carbon nanotube wires on the connecting object side, so the connection work is complicated. In addition, due to the use of a catalyst solution, there is a problem of difficulty in positionally controlling the parts where the carbon nanotube wires are connected to each other.

[0005] In addition, as described above, since CNT has excellent conductivity, CNT wires are expected to be used as electric wires, etc., and the connection object is not only the CNT wire but also a substrate such as a circuit board. However, in Patent Document 1, in which carbon nanotubes are grown and entangled with a carbon nanotube wire on the connection object side, there is a problem that a connection body cannot be formed when the connection object is other than the CNT wire.

[0006] On the other hand, when connecting a metal wire to a connection object, the connection is sometimes made by welding because the connection work is simple and the connection strength can be obtained. However, compared with metal wires, the solder wettability of CNT wires is poor, and especially when the CNT wires are stranded wires obtained by stranding wires composed of carbon nanotube aggregates, it is difficult for the solder to penetrate into the inside of the CNT wires, so there are problems with the conductivity and strength of the connection.

[0007] Therefore, when the CNT wire is connected to the object to be connected by welding, the CNT wire needs to be treated to be hydrophilic or surface roughened in advance. Therefore, when welding the CNT wire, there is still a problem that the connection work is complicated.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2013-47402 Summary of the invention

[0011] Problems to be solved by the invention

[0012] The present invention has been made in view of the above circumstances, and an object thereof is to provide a carbon nanotube wire connection structure which can be connected to a connection object of the carbon nanotube wire at a desired position by simple operation, and the connection portion between the carbon nanotube wire and the connection object is excellent in electrical connectivity and mechanical connectivity.

[0013] Means used to solve problems

[0014] The gist of the present invention is as follows.

[0015] [1] A carbon nanotube wire connection structure, comprising: a carbon nanotube wire formed by twisting and bundling a carbon nanotube aggregate; an object to be connected to the carbon nanotube wire; a wire having higher solder wettability than the carbon nanotube wire; a through portion of the wire formed along a cross section of a component orthogonal to a length direction of the carbon nanotube wire; and solder connecting the carbon nanotube wire and the object to be connected, the solder being immersed in the through portion formed along the wire.

[0016] [2] The carbon nanotube wire connection structure according to [1], wherein the connection object is a conductive member.

[0017] [3] The carbon nanotube wire connection structure according to [2], wherein the conductive member is a substrate having a metal member or other carbon nanotube wires.

[0018] [4] The carbon nanotube wire connection structure according to any one of [1] to [3], wherein a portion of the conductive wire protrudes from a portion of the carbon nanotube wire that is not opposed to the connection object.

[0019] [5] The carbon nanotube wire connection structure according to any one of [1] to [4], wherein

[0020] The connection object is another carbon nanotube wire.

[0021] The carbon nanotube wire connection structure includes a connection portion, in which one end of the carbon nanotube wire contacts the outer peripheral surface of one end of the other carbon nanotube wire.

[0022] In the connection portion, the through portion of the conducting wire is formed along a cross section having a component that is orthogonal to the longitudinal directions of the carbon nanotube wire and the other carbon nanotube wire.

[0023] [6] The carbon nanotube wire connection structure according to any one of [1] to [4], wherein at least a portion of the conductive wire other than a portion located in the through-portion is wound around the outer periphery of the carbon nanotube wire.

[0024] [7] The carbon nanotube wire connection structure according to [5], wherein at least a portion of the conductive wire other than a portion located in the through-portion is wound around the outer periphery of the carbon nanotube wire and the other carbon nanotube wire.

[0025] [8] A carbon nanotube wire connection structure according to any one of [1] to [7], wherein, in a cross section having a component orthogonal to the length direction of the carbon nanotube wire, a ratio of a cross-sectional area of ​​the wire in the through portion to a cross-sectional area of ​​the carbon nanotube wire is greater than or equal to 5% and less than or equal to 99%.

[0026] Effects of the Invention

[0027] According to the embodiment of the carbon nanotube wire connection structure of the present invention, a wire penetration portion with high solder wettability is formed along a cross section having a component orthogonal to the length direction of the carbon nanotube wire as a strand, and the solder penetrates the penetration portion along the wire, thereby making it easy to form a portion with high solder wettability (i.e., the wire penetration portion) inside the carbon nanotube wire as a strand, such as a region surrounded by the surface of the carbon nanotube aggregate and the surface of the wire in the penetration portion. Therefore, the solder flows into the interior of the carbon nanotube wire along the penetration portion of the wire, and the solder, the wire and the connection object are firmly connected, and as a result, the carbon nanotube wire and the connection object are firmly connected. As described above, the carbon nanotube wire connection structure of the present invention can be connected to the connection object of the carbon nanotube wire at a desired position by a simple operation, and a carbon nanotube wire connection structure having excellent electrical connectivity and mechanical connectivity at the connection portion between the carbon nanotube wire and the connection object can be obtained.

[0028] According to the aspect of the carbon nanotube wire connection structure of the present invention, a portion of the wire protrudes from a portion of the carbon nanotube wire that does not face the connection object, so that solder can smoothly flow into the carbon nanotube wire through the protruding portion of the wire.

[0029] According to the method of the carbon nanotube wire connection structure of the present invention, by having a winding portion, at least a portion of the wire other than the portion located at the through portion is wound around the outer periphery of the carbon nanotube wire, so that solder is accumulated in the above-mentioned winding portion. Therefore, the solder is reliably applied to the desired connection portion and its vicinity, and the solder can flow into the interior of the carbon nanotube wire more smoothly. In addition, since the solder is easily accumulated in the winding portion, it is possible to prevent the solder from infiltrating and spreading to portions other than the desired connection portion and its vicinity.

[0030] According to the method of the carbon nanotube wire connection structure of the present invention, the ratio of the cross-sectional area of ​​the through portion to the cross-sectional area of ​​the carbon nanotube wire is greater than 5% and less than 99%, thereby allowing the solder to more reliably flow into the interior of the carbon nanotube wire, thereby more reliably improving the connection reliability between the carbon nanotube wire and the connection object. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is an explanatory diagram of a connection structure according to a first embodiment of the present invention, that is, a connection structure in which carbon nanotube wires are connected to a substrate.

[0032] Figure 2 This is an explanatory diagram of forming a through portion of a conductive wire in a carbon nanotube wire used in a connection structure according to the first embodiment of the present invention.

[0033] Figure 3 This is an explanatory diagram of a state in which a conductive wire is wound around the outer periphery of a carbon nanotube wire having a conductive wire penetration portion formed therein, which is used in the connection structure according to the first embodiment of the present invention.

[0034] Figure 4 This is an explanatory diagram of a connection structure according to a second embodiment of the present invention, that is, a connection structure in which a carbon nanotube wire is connected to another carbon nanotube wire.

[0035] Figure 5 This is an explanatory diagram of a state in which a conductive wire is wound around the outer periphery of a carbon nanotube wire having a conductive wire penetration portion formed therein, which is used in a connection structure according to a third embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following is a description of the carbon nanotube wire connection structure of the present invention. First, a description is given of the carbon nanotube wire connection structure according to the first embodiment of the present invention. Figure 1 This is an explanatory diagram of a connection structure according to a first embodiment of the present invention, that is, a connection structure in which carbon nanotube wires are connected to a substrate. Figure 2 This is an explanatory diagram of forming a wire penetration portion in a carbon nanotube wire used in a connection structure according to the first embodiment of the present invention. Figure 3This is an explanatory diagram of a state in which a conductive wire is wound around the outer periphery of a carbon nanotube wire having a conductive wire penetration portion formed therein, which is used in the connection structure according to the first embodiment of the present invention.

[0037] like Figure 1 As shown, the carbon nanotube wire connection structure 1 according to the first embodiment of the present invention includes a carbon nanotube wire (CNT wire) 10 formed by twisting and bundling a carbon nanotube aggregate (hereinafter, sometimes referred to as a CNT aggregate), and a connection object to which the CNT wire 10 is connected. The connection object of the CNT wire 10 is a conductive member. In the carbon nanotube wire connection structure 1, the connection object is a substrate 20, and as the substrate 20, for example, a substrate having a metal member such as a metal substrate and a circuit substrate can be cited.

[0038] In the carbon nanotube wire connection structure 1, the vicinity of the end of the CNT wire 10 is connected to the substrate 20 to form a connection portion 40 between the CNT wire 10 and the substrate 20. A solder 41 is used to connect the CNT wire 10 and the substrate 20. Therefore, the solder 41 connects the CNT wire 10 and the substrate 20 as a connection object, so that the CNT wire 10 is soldered to the substrate 20.

[0039] The CNT wire 10 is formed by twisting and bundling a plurality of wires composed of a carbon nanotube aggregate (CNT aggregate), wherein the carbon nanotube aggregate is composed of a plurality of carbon nanotubes (CNTs) having a layer structure of more than one layer. Therefore, the CNT wire 10 is a strand formed by twisting wires composed of CNT aggregates. Here, the CNT wire 10 refers to a CNT wire 10 in which the proportion of CNT is more than 90% by mass. It should be noted that in the calculation of the CNT proportion in the CNT wire 10, the plating layer and the dopant are removed. The length direction of the CNT aggregate forms the length direction of the CNT wire 10. Therefore, the CNT aggregate becomes linear. The plurality of CNT aggregates in the CNT wire 10 are arranged so that their long axis directions are roughly aligned. Therefore, the plurality of CNT aggregates in the CNT wire 10 are oriented.

[0040] like Figure 2As shown in FIG. 1 , in the carbon nanotube wire connection structure 1, there are included a wire 30 having higher solder wettability than the CNT wire 10, and a through portion 31 of the wire 30 formed along a cross section orthogonal to the longitudinal direction of the CNT wire 10. The wire 30 is made to penetrate the CNT wire 10 along the radial direction of the CNT wire 10, so that the through portion 31 of the wire 30 is formed along the cross section orthogonal to the longitudinal direction of the CNT wire 10. In the carbon nanotube wire connection structure 1, the wire 30 penetrates along the center line of the cross section orthogonal to the longitudinal direction of the CNT wire 10. In addition, in the carbon nanotube wire connection structure according to the embodiment of the present invention, for the sake of convenience of explanation, the through portion 31 of the wire 30 is formed on the cross section orthogonal to the longitudinal direction of the CNT wire 10, but it is not limited to the cross section orthogonal to the longitudinal direction as long as it has a component orthogonal to the longitudinal direction of the CNT wire 10.

[0041] As described above, the extending direction of the through-portion 31 of the conductive wire 30 is substantially perpendicular to the longitudinal direction of the CNT wire 10. Since the CNT wire 10 is a stranded wire formed by stranding wires composed of CNT aggregates, the conductive wire 30 can be inserted into the CNT wire 10 even if no through-hole or the like is formed separately in the CNT wire 10. In addition, by inserting the conductive wire 30 into the CNT wire 10, a gap is formed between the CNT wire 10 and the conductive wire 30. In the carbon nanotube wire connection structure 1, one through-portion 31 is formed by inserting one conductive wire 30 into the CNT wire 10. On the other hand, the through-portion does not necessarily need to be substantially perpendicular to the longitudinal direction of the CNT wire. For example, the conductive wire may be folded back in the CNT wire 10, and both ends of the conductive wire may protrude from any position of the outer periphery of the CNT wire 10. Therefore, the through-portion 31 may be formed by bending in the CNT wire 10. In the present embodiment, as described later, a structure may be adopted in which the solder flows into the interior of the CNT wire 10 (that is, into the gap formed between the outer periphery of the conductive wire 30 and the CNT aggregate).

[0042] By inserting the conductive wire 30 into the CNT wire 10, a gap is also formed between the CNT wire 10 and the conductive wire 30, so when the CNT wire 10 is welded to the substrate 20, the solder 41 passes through the through-portion 31 along the conductive wire 30. That is, when the CNT wire 10 is welded to the substrate 20, the solder flows along the gap formed between the outer periphery of the conductive wire 30 and the CNT wire 10, that is, the inside of the CNT wire 10, and the solder 41 passes through the through-portion 31. As described above, the formation direction of the solder 41 is substantially orthogonal to the length direction of the CNT wire 10. It should be noted that in Figure 2In order to facilitate the description of the carbon nanotube wire connection structure 1, the solder 41 applied to the through-hole 31 when the CNT wire 10 is soldered to the substrate 20 is also shown.

[0043] like Figure 3 As shown, in the connection portion 40, at least a portion of the wire 30 other than the portion located in the through portion 31 is wound around the outer peripheral surface 11 of the CNT wire 10 along the circumferential direction of the CNT wire 10 to form a winding portion 32. As can be seen from the above, the through portion 31 and the winding portion 32 of the wire 30 are continuous with each other. The winding portion 32 is provided near the through portion 31. The winding portion 32 of the wire 30 is provided in a manner in contact with the outer peripheral surface 11 of the CNT wire 10. Since the through portion 31 of the wire 30 and the winding portion 32 wound along the circumferential direction of the CNT wire 10 are continuous with each other, the solder 41 easily flows into the interior of the CNT wire 10, and the connection strength between the CNT wire 10 and the substrate 20 is improved.

[0044] By forming the winding portion 32 of the wire 30, a part of the wire 30 protrudes from the portion of the CNT wire 10 that is not facing the substrate 20. That is, the wire 30 protrudes from the outer peripheral surface 11 of the CNT wire 10 at the winding portion 32 of the wire 30. Figure 3 In the embodiment, the front end portion 33 of the wire 30 located in the through-portion 31 also extends outward from the outer peripheral surface 11 of the CNT wire 10, so that a part of the wire 30 protrudes from the portion of the CNT wire 10 that is not opposed to the substrate 20. In addition, when the connection object is the substrate 20, the end portion (front end portion 33) of the wire 30 where the through-portion 31 is not formed may be connected to the substrate 20 in advance by welding or the like.

[0045] The number of turns of the wire 30 in the winding portion 32 is not particularly limited, and may be one turn or multiple turns. Figure 3 In the figure, for the sake of convenience, the number of turns of the wire 30 is set to 4. In the winding portion 32, the wire 30 is separated by a predetermined interval in the longitudinal direction of the CNT wire 10 and is wound along the circumferential direction of the CNT wire 10. In addition, when the CNT wire 10 is soldered to the substrate 20, the winding portion 32 has the function of storing the solder 41. Figure 3 In FIG. 1 , the solder 41 applied when the CNT wire 10 is soldered to the substrate 20 is also shown on the carbon nanotube wire connection structure 1 .

[0046] As the conductive wire 30 having higher solder wettability than the CNT wire 10, for example, metal wires such as copper, silver, platinum, and tungsten can be cited. In addition, the type of solder is not particularly limited as long as it can be used for connecting metal parts, and for example, lead-containing solders such as Sn-Pb series, and lead-free solders such as Sn-Ag-Cu series, Sn-Cu series, and Sn-Zn series can be cited. In addition, the amount of solder 41 applied to a through portion 31 is not particularly limited, but from the viewpoint of improving the tensile strength and electrical connectivity of the connecting portion 40, the lower limit is preferably 3.0 mg. On the other hand, from the viewpoint of weight reduction, the upper limit of the solder 41 applied to a through portion 31 is preferably 20 mg, and particularly preferably 6.0 mg.

[0047] The diameter of the CNT wire 10 is not particularly limited, and may be, for example, 20 μm to 1 mm. In addition, the number of twisted CNT strands constituting the CNT wire 10 is not particularly limited, and may be, for example, 2 to 2,000. In addition, the diameter of the conductor 30 is not particularly limited, and may be, for example, 10 μm or more and less than 1 mm.

[0048] According to the carbon nanotube wire connection structure 1, the through-portion 31 of the wire 30 is formed along the cross section orthogonal to the length direction of the CNT wire 10 as a strand and has high solder wettability, and the solder 41 passes through the through-portion 31 along the wire 30, thereby making it easy to form the inside of the CNT wire 10 with high solder wettability (that is, the gap formed between the outer periphery of the wire 30 and the CNT wire 10). Therefore, when the CNT wire 10 is soldered to the substrate 20, the solder 41 flows into the inside of the CNT wire 10 along the through-portion 31 of the wire 30, that is, along the radial direction of the CNT wire 10, and the solder 41, the wire 30 and the substrate 20 are firmly connected, and as a result, the CNT wire 10 and the substrate 20 are firmly connected. As can be seen from the above, in the carbon nanotube wire connection structure 1, by appropriately selecting the position of the through portion 31 of the wire 30 on the CNT wire 10, the CNT wire 10 can be firmly connected to the substrate 20 at a desired position by a simple operation. In addition, the carbon nanotube wire connection structure 1 can obtain a carbon nanotube wire connection structure having excellent electrical connectivity and mechanical connectivity at the connection portion 40 between the CNT wire 10 and the substrate 20.

[0049] In addition, in the carbon nanotube wire connection structure 1, a portion of the wire 30 protrudes from the portion of the CNT wire 10 that is not opposite to the substrate 20, thereby allowing the solder 41 to smoothly flow into the interior of the CNT wire 10 along the extending direction of the wire 30 through the protruding portion of the wire 30.

[0050] In addition, the conductive wire 30 of the carbon nanotube wire connection structure 1 has a winding portion 32 in which at least a portion other than the portion located at the through portion 31 is wound around the outer peripheral surface 11 of the CNT wire 10, so that when the CNT wire 10 is soldered to the substrate 20, the solder 41 is stored in the winding portion 32. Therefore, the solder 41 is reliably applied to the desired connection portion 40 and its vicinity, and the solder 41 can flow more smoothly into the inside of the CNT wire 10 along the extending direction of the conductive wire 30. In addition, since the solder 41 is easily stored in the winding portion 32, it is possible to prevent the solder 41 from wetting and spreading to portions other than the desired connection portion 40 and its vicinity.

[0051] In the cross section perpendicular to the longitudinal direction of the CNT wire 10, the ratio of the cross-sectional area of ​​the wire 30 in the through portion 31 to the cross-sectional area of ​​the CNT wire 10 is not particularly limited, but is preferably 5% or more and 99% or less, more preferably 10% or more and 99% or less, and particularly preferably 30% or more and 50% or less. In particular, when the cross-sectional area of ​​the wire 30 is 30% or more and 50% or less, the performance of electrical connectivity and mechanical connectivity reaches a peak, which is also preferred from the viewpoint of lightness and cost. From the viewpoint of more reliably improving the connection reliability between the CNT wire 10 and the substrate 20 by allowing the solder 41 to flow into the CNT wire 10 along the extending direction of the wire 30, the lower limit of the cross-sectional area is preferably 10%, and from the viewpoint of electrical connectivity, the lower limit is particularly preferably 30%. On the other hand, from the viewpoint of operability when forming the through portion 31 and the winding portion 32, the upper limit of the ratio of the cross-sectional area is preferably 99%, and from the viewpoint of achieving a balance between lightness and electrical connectivity, it is particularly preferably 50%. It should be noted that the ratio of the cross-sectional areas is calculated by (the radial cross-sectional area of ​​the wire 30 in the through-portion 31 / the radial cross-sectional area of ​​the CNT wire 10) × 100. By setting the ratio of the cross-sectional areas to the above values, the surface area of ​​the wire 30 penetrating the carbon nanotube wire can be ensured, and the solder can be easily impregnated. As a result, a carbon nanotube wire connection structure having excellent electrical and mechanical connectivity can be obtained.

[0052] Next, a carbon nanotube wire connection structure according to a second embodiment of the present invention will be described using the accompanying drawings. It should be noted that the carbon nanotube wire connection structure according to the second embodiment has the same main components as the carbon nanotube wire connection structure according to the first embodiment, and therefore the same components as those of the carbon nanotube wire connection structure according to the first embodiment are described using the same reference numerals. Figure 4 It is an explanatory diagram of a connection structure according to a second embodiment of the present invention, that is, a connection structure in which a carbon nanotube wire is connected to another carbon nanotube wire.

[0053] In the carbon nanotube wire connection structure according to the first embodiment, the connection object as the conductive member is a substrate. Figure 4 As shown, in the carbon nanotube wire connection structure 2 according to the second embodiment, the connection object as the conductive member is another CNT wire 50. In the carbon nanotube wire connection structure 2, one end 12 of the CNT wire 10 is connected to one end 52 of the other CNT wire 50 to form a connection portion 40 between the CNT wire 10 and the other CNT wire 50. In the carbon nanotube wire connection structure 2, the direction extending from the one end 12 of the CNT wire 10 to the other end (not shown) is different from the direction extending from the one end 52 of the other CNT wire 50 to the other end (not shown).

[0054] In addition, in the connection portion 40, the one end 12 of the CNT wire 10 is arranged in parallel with the one end 52 of the other CNT wire 50. In addition, in the connection portion 40, the one end 12 of the CNT wire 10 is connected to the one end 52 of the other CNT wire 50 in a state where the outer peripheral surface 11 of the CNT wire 10 is in contact with the outer peripheral surface 51 of the other CNT wire 50.

[0055] The connecting portion 40 is provided with a through portion 31 of the wire 30. The through portion 31 of the wire 30 is formed along a cross section perpendicular to the length direction of the portion of the CNT wire 10 and the other CNT wire 50 arranged in parallel. The through portion 31 of the wire 30 is formed along a cross section perpendicular to the length direction of the portion of the CNT wire 10 and the other CNT wire 50 arranged in parallel by passing the wire 30 through the CNT wire 10 and the other CNT wire 50 along the radial direction of the CNT wire 10 and the other CNT wire 50. In the connection structure 2 of carbon nanotube wires, the wire 30 is passed along the center line of the cross section perpendicular to the length direction of the one end 12 of the CNT wire 10 and the one end 52 of the other CNT wire 50 arranged in parallel. That is, the wire 30 has a through portion 31 continuous with both the CNT wire 10 and the other CNT wire 50.

[0056] In the carbon nanotube wire connection structure 2, by inserting the conductive wire 30 into the portion of the CNT wire 10 and the other CNT wire 50 arranged in parallel, the conductive wire 30 can penetrate the CNT wire 10 and the other CNT wire 50 to form a through portion 31. In the carbon nanotube wire connection structure 2, one conductive wire 30 is also inserted into the CNT wire 10 and the other CNT wire 50 to form one through portion 31. It should be noted that the other CNT wire 50 is a stranded wire formed by twisting a plurality of CNT wires, similar to the CNT wire 10.

[0057] When the end 12 of the CNT wire 10 is welded to the end 52 of the other CNT wire 50 to lengthen the CNT wire, the solder 41 passes through the through-portion 31 along the conductive wire 30. Therefore, the solder 41 spreads from the inside of the CNT wire 10 to the inside of the other CNT wire 50 along the through-portion 31.

[0058] like Figure 4 As shown in FIG. 1 , at least a portion of the conductive wire 30 other than the portion located at the through portion 31 is wound in the circumferential direction around the outer periphery of the CNT wire 10 and the other CNT wire 50 to form a wound portion 32. The wound portion 32 is provided at a portion where the CNT wire 10 and the other CNT wire 50 are arranged in parallel. In the wound portion 32, the conductive wire 30 is wound so as to bundle the end 12 of the CNT wire 10 and the end 52 of the other CNT wire 50. In the carbon nanotube wire connection structure 2, the through portion 31 and the wound portion 32 of the conductive wire 30 are also continuous with each other, and the wound portion 32 is provided near the through portion 31.

[0059] In the carbon nanotube wire connection structure 2, the winding portion 32 of the wire 30 is also formed so that a part of the wire 30 protrudes from the portion of the CNT wire 10 that is not opposite to the other CNT wires 50. That is, the wire 30 protrudes from the outer peripheral surface 11 of the CNT wire 10 at the winding portion 32 of the wire 30. Figure 4 In the embodiment, the front end portion 33 of the wire 30 located in the through portion 31 extends outward from the outer peripheral surface 11 of the CNT wire 10 , so that a part of the wire 30 protrudes from a portion of the CNT wire 10 that does not face other CNT wires 50 .

[0060] In the carbon nanotube wire connection structure 2, when the CNT wire 10 and the other CNT wire 50 are welded, the winding portion 32 also has the function of storing the solder 41. Therefore, the solder 41 can flow more smoothly into the inside of the CNT wire 10 and the inside of the other CNT wire 50 along the extension direction of the wire 30. Furthermore, in the carbon nanotube wire connection structure 2, the winding portion 32 has the function of further improving the bonding strength of the connection portion 40 between the CNT wire 10 and the other CNT wire 50. Furthermore, in the carbon nanotube wire connection structure 2, since the wire 30 has the function of directly connecting the CNT wire 10 and the other CNT wire 50, the tensile strength between the CNT wire 10 and the other CNT wire 50 can be improved.

[0061] The width of the winding portion 32 in the longitudinal direction of the CNT wire 10 is not particularly limited, but from the viewpoint of reliably welding the CNT wire 10 to other CNT wires 50, the lower limit is preferably 0.3 mm or more, and from the viewpoint of further improving the bonding strength of the connection portion, the lower limit is particularly preferably 0.5 mm or more. On the other hand, from the viewpoint of reducing the weight of the connection portion 40, the upper limit of the width of the winding portion 32 is preferably 3.0 mm or less, and particularly preferably 2.0 mm or less.

[0062] According to the carbon nanotube wire connection structure 2, a through portion 31 of the wire 30 having high solder wettability is provided along a cross section orthogonal to the length direction of the CNT wire 10 as a strand and the length direction of the other CNT wire 50 as a connection object, and the solder 41 passes through the through portion 31 along the wire 30, thereby making it easy to form an interior with high solder wettability on the CNT wire 10 and the other CNT wire 50 (that is, a gap formed between the outer periphery of the wire 30 and the CNT wire 10 and the other CNT wire 50). Therefore, when the CNT wire 10 and the other CNT wire 50 are connected, the solder 41 flows into the inside of the CNT wire 10 and the inside of the other CNT wire 50 along the through-portion 31 of the wire 30, that is, along the radial direction of the CNT wire 10 and the other CNT wire 50, and the solder 41, the wire 30, the CNT wire 10 and the other CNT wire 50 are respectively firmly connected, and as a result, the CNT wire 10 and the other CNT wire 50 are firmly connected. As can be seen from the above, in the carbon nanotube wire connection structure 2, by appropriately selecting the position of the through-portion 31 of the wire 30 on the CNT wire 10, the CNT wire 10 can be firmly connected to the other CNT wire 50 at a desired position by a simple operation, and the size of the CNT wire can be easily increased. In addition, in the carbon nanotube wire connection structure 2, a carbon nanotube wire connection structure having excellent electrical connectivity and mechanical connectivity at the connection portion 40 between the CNT wire 10 and the other CNT wire 50 can be obtained.

[0063] Next, the carbon nanotube wire connection structure according to the third embodiment of the present invention will be described using the accompanying drawings. It should be noted that the carbon nanotube wire connection structure according to the third embodiment has the same main components as the carbon nanotube wire connection structure according to the first and second embodiments, and therefore the same components as the carbon nanotube wire connection structure according to the first and second embodiments are described using the same reference numerals. Figure 5 This is an explanatory diagram of a connection structure according to a third embodiment of the present invention, in which a conductive wire is wound around the outer periphery of a carbon nanotube wire having a conductive wire penetration portion.

[0064] like Figure 5As shown, in the carbon nanotube wire connection structure 3 according to the third embodiment, a through portion 31 and a winding portion 32 of a conductive wire 30 are formed at the front end portion 13 of the CNT wire 10. In the carbon nanotube wire connection structure 3, the object to be connected with the CNT wire 10 is, for example, a substrate or another CNT wire ( Figure 5 The front end portion 13 of the CNT wire 10 is welded to the connection object.

[0065] By forming the winding portion 32 on the CNT wire 10, the outer periphery of the CNT wire 10 is held by the winding portion 32, so that pressure is applied from the outer peripheral surface, which can prevent the contact area between CNTs from decreasing and prevent the decrease in conductivity. At this time, it is preferable to apply pressure roughly evenly to the entire outer peripheral surface of the CNT wire 10 formed with the winding portion 32. As a method of applying pressure roughly evenly to the entire surface of the winding portion 32, for example, a method of increasing the number of turns of the winding portion 32 or setting the start and end points of the winding portion 32 at positions parallel to the length direction of the CNT wire 10 can be cited.

[0066] Next, other embodiments of the connection structure of the carbon nanotube wire of the present invention are described. In the connection structure of the carbon nanotube wire of each of the above embodiments, a winding portion of the wire is provided, but as long as a through portion of the wire is formed, the winding portion may not be provided. In addition, in the connection structure of the carbon nanotube wire of each of the above embodiments, a through portion and a winding portion are provided on one wire, but instead, a through portion and a winding portion may be provided on a plurality of wires. Therefore, a plurality of through portions of the wire may be provided. By providing a plurality of through portions of the wire, the surface area of ​​the wire of the through portion is further increased, and the solder is more easily impregnated. The plurality of through portions of the wire may be formed in a cross section having a component orthogonal to the length direction of the CNT wire, or may be formed in a plurality of cross sections having a component orthogonal to the length direction of the CNT wire. By forming the plurality of through portions of the wire in a cross section having a component orthogonal to the length direction of the CNT wire, the area of ​​the connection portion to which the solder is applied is narrowed, and thus a compact connection structure of the carbon nanotube wire can be formed. Furthermore, by forming the plurality of through-portions of the conductive wire in the plurality of cross sections having components orthogonal to the longitudinal direction of the CNT wire, the region of the connection portion to which solder is applied becomes wider, thereby further improving the bonding strength of the connection portion.

[0067] In the carbon nanotube wire connection structure of each embodiment described above, the conductive wires are wound at predetermined intervals in the longitudinal direction of the CNT wires in the winding portion. However, the conductive wires may be wound in contact with each other without predetermined intervals.

[0068] Example

[0069] Next, examples of the present invention will be described, but the present invention is not limited to the following examples.

[0070] First, CNTs are prepared, and CNT strands are prepared from the obtained plurality of CNTs. Next, the obtained plurality of CNT strands are twisted to prepare CNT strands. CNTs can be prepared, for example, by methods such as the floating catalytic method (Japanese Patent No. 5819888) and the substrate method (Japanese Patent No. 5590603). In addition, CNT strands can be prepared, for example, by methods such as dry spinning (Japanese Patent No. 5819888, Japanese Patent No. 5990202, Japanese Patent No. 5350635), wet spinning (Japanese Patent No. 5135620, Japanese Patent No. 5131571, Japanese Patent No. 5288359), and liquid crystal spinning (Japanese Patent No. 2014-530964 Gazette).

[0071] Example 1

[0072] Prepare two CNT wires (diameter 0.2mm) formed by twisting 7 CNT wires, and arrange the ends of the two CNT wires in parallel. Prepare a copper wire (diameter 0.025mm) as a conductor, insert the copper wire into the position where the two CNT wires are arranged in parallel, and form a through-portion of the copper wire on the two CNT wires. Then, bundle the two CNT wires, and use the copper wire forming the through-portion to wrap the outer periphery of the two CNT wires to form a winding portion, thereby making a connected structure. The width of the winding portion is 1mm.

[0073] Example 2

[0074] A connection structure was prepared in the same manner as in Example 1 except that two copper wires were used as conductors instead of one copper wire and the two copper wires were inserted substantially orthogonally in a cross section orthogonal to the longitudinal direction of the CNT wire.

[0075] Example 3

[0076] A connection structure was produced in the same manner as in Example 1 except that a copper wire having a diameter of 0.080 mm was used instead of a copper wire having a diameter of 0.025 mm.

[0077] Example 4

[0078] A connection structure was prepared in the same manner as in Example 3 except that two copper wires were used instead of one copper wire and the two copper wires were inserted substantially orthogonally in a cross section orthogonal to the longitudinal direction of the CNT wire.

[0079] Example 5

[0080] A connection structure was produced in the same manner as in Example 1 except that a copper wire having a diameter of 0.250 mm was used instead of a copper wire having a diameter of 0.025 mm.

[0081] Example 6

[0082] A connection structure was prepared in the same manner as in Example 5 except that two copper wires were used instead of one copper wire and the two copper wires were inserted substantially orthogonally in a cross section orthogonal to the longitudinal direction of the CNT wire.

[0083] Solder was applied to the through-hole and the winding part to connect two CNT wires, so that the CNT wires were elongated in a straight line, and a sample of the carbon nanotube wire connection structure of the present invention was prepared. As solder, lead-based solder was used in all Examples 1 to 6. In addition, as a reference example, an unconnected CNT wire (a CNT wire (diameter 0.2 mm) formed by twisting 7 CNT wires) was used.

[0084] The evaluation items and evaluation methods are as follows.

[0085] (1) Ratio of the radial cross-sectional area of ​​the conductive wire to the radial cross-sectional area of ​​the carbon nanotube wire in the through-portion of the carbon nanotube wire connection structure

[0086] The ratio of the radial cross-sectional area of ​​the conductive wire in the through-portion of the carbon nanotube wire connection structure to the radial cross-sectional area of ​​the carbon nanotube wire is obtained by cutting a cross section of the carbon nanotube wire connection structure and calculating the radial cross-sectional area of ​​the conductive wire in the through-portion / the radial cross-sectional area of ​​the CNT wire based on an image obtained by SEM.

[0087] (2) Resistance value

[0088] Regarding the resistance value of the carbon nanotube wire connection structure, the carbon nanotube wire connection structure was connected to a low voltage source meter (manufactured by Keithley, device name "2401 Source Meter") and a digital multimeter (manufactured by Keithley, device name "2000 Multimeter"), and the resistance was measured by a four-wire detection method.

[0089] (3) Tensile strength

[0090] The tester held both ends of a sample of a carbon nanotube wire connection structure and pulled it, and visually observed the connection condition of the sample.

[0091] ○: Even if stretched, the connection will not break and the connection structure will not change;

[0092] Δ: The connection structure changes when stretched, but the electrical connection can be maintained;

[0093] ×: The connection part came apart when stretched.

[0094] The evaluation results are shown in Table 1 below.

[0095] Table 1

[0096]

[0097] As can be seen from Table 1, in Examples 1 to 6, which are connection structures connecting two CNT wires with solder, the resistance value can be reduced to the same level as that of a single CNT wire, and the electrical connectivity is excellent. In addition, in Examples 1 to 6, the tensile strength is good and the mechanical connectivity is excellent. In particular, in Examples 2 to 6, where the ratio of the copper wire to the cross-sectional area of ​​the carbon nanotube is 10% or more, the mechanical connectivity is even better. In addition, in Examples 4 to 6 where the ratio of the copper wire is 30% or more, it is confirmed that the resistance value is significantly reduced.

[0098] Furthermore, when the connection portions of Examples 1 to 6 were connected to the substrate using solder, they were also excellent in mechanical strength and electrical connectivity.

[0099] Explanation of symbols

[0100] 1, 2, 3 Carbon nanotube wire connection structure

[0101] 10 Carbon Nanotube Wire

[0102] 30 Wire

[0103] 31 Through

[0104] 41 Solder

Claims

1. A carbon nanotube wire connection structure, wherein: include: A carbon nanotube wire formed by twisting and bundling a carbon nanotube assembly; A connection object to which the carbon nanotube wire is connected; A conductor having higher solder wettability than the carbon nanotube wire; a through portion of the conductive wire formed along a cross section perpendicular to the length direction of the carbon nanotube wire; as well as solder connecting the carbon nanotube wire and the object to be connected, The solder penetrates into the through-portion, and the through-portion is formed along the conductive line.

2. The carbon nanotube wire connection structure according to claim 1, wherein: The connection object is a conductive member.

3. The carbon nanotube wire connection structure according to claim 2, wherein: The conductive member is a substrate having a metal member or other carbon nanotube wires.

4. The carbon nanotube wire connection structure according to any one of claims 1 to 3, wherein: A portion of the conductive wire protrudes from a portion of the carbon nanotube wire that is not opposed to the connection target object.

5. The carbon nanotube wire connection structure according to any one of claims 1 to 3, wherein: The connection object is another carbon nanotube wire. The carbon nanotube wire connection structure includes a connection portion, in which one end of the carbon nanotube wire contacts the outer peripheral surface of one end of the other carbon nanotube wire. In the connection portion, the through portion of the conducting wire is formed along a cross section orthogonal to the length direction of the carbon nanotube wire and the other carbon nanotube wire.

6. The carbon nanotube wire connection structure according to claim 4, wherein: The connection object is another carbon nanotube wire. The carbon nanotube wire connection structure includes a connection portion, in which one end of the carbon nanotube wire contacts the outer peripheral surface of one end of the other carbon nanotube wire. In the connection portion, the through portion of the conducting wire is formed along a cross section orthogonal to the length direction of the carbon nanotube wire and the other carbon nanotube wire.

7. The carbon nanotube wire connection structure according to any one of claims 1 to 3, wherein: At least a portion of the conductive wire other than a portion located in the through-hole is wound around the outer periphery of the carbon nanotube wire.

8. The carbon nanotube wire connection structure according to claim 4, wherein: At least a portion of the conductive wire other than a portion located in the through-hole is wound around the outer periphery of the carbon nanotube wire.

9. The carbon nanotube wire connection structure according to claim 5, wherein: At least a portion of the conductive wire other than a portion located in the through portion is wound around the outer periphery of the carbon nanotube wire and the other carbon nanotube wire.

10. The carbon nanotube wire connection structure according to claim 6, wherein: At least a portion of the conductive wire other than a portion located in the through portion is wound around the outer periphery of the carbon nanotube wire and the other carbon nanotube wire.

11. The carbon nanotube wire connection structure according to any one of claims 1 to 3, 6, and 8 to 10, wherein: In a cross section perpendicular to the longitudinal direction of the carbon nanotube wire, a ratio of a cross-sectional area of ​​the conductive wire in the through-portion to a cross-sectional area of ​​the carbon nanotube wire is 5% or more and 99% or less.

12. The carbon nanotube wire connection structure according to claim 4, wherein: In a cross section perpendicular to the longitudinal direction of the carbon nanotube wire, a ratio of a cross-sectional area of ​​the conductive wire in the through-portion to a cross-sectional area of ​​the carbon nanotube wire is 5% or more and 99% or less.

13. The carbon nanotube wire connection structure according to claim 5, wherein: In a cross section perpendicular to the longitudinal direction of the carbon nanotube wire, a ratio of a cross-sectional area of ​​the conductive wire in the through-portion to a cross-sectional area of ​​the carbon nanotube wire is 5% or more and 99% or less.

14. The carbon nanotube wire connection structure according to claim 7, wherein: In a cross section perpendicular to the longitudinal direction of the carbon nanotube wire, a ratio of a cross-sectional area of ​​the conductive wire in the through-portion to a cross-sectional area of ​​the carbon nanotube wire is 5% or more and 99% or less.

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