JP2019065431A - Carbon nanotube wire, carbon nanotube wire connection structure, and method for manufacturing carbon nanotube wire - Google Patents

Abstract

To provide a carbon nanotube wire in which contact resistance between carbon nanotube bundles can be reduced and generation of overcurrent can be suppressed.SOLUTION: A CNT wire 1 is a CNT wire formed by twisting a plurality of CNT bundles 11,11,--- and is provided along the longitudinal direction of the CNT wire 1, and comprises a plating part 12 disposed in the inside part and the surface layer part of the CNT wire, and in which, in a cross section in a direction perpendicular to the longitudinal direction of CNT wire 1, the ratio of the value obtained by dividing the number of CNT bundles in which the ratio of the length of a portion where a plated part with a thickness of 1 μm or more is formed on the surface of the CNT bundle to the surface entire length of the CNT bundle 11 is 0.5 or more, by the total number of the plural CNT bundles 11,11,--- is 70% or more.SELECTED DRAWING: Figure 1

Description

  The present invention is a carbon nanotube wire constituted by twisting together a plurality of carbon nanotube bundles formed by bundling a plurality of carbon nanotubes, a carbon nanotube wire connection structure comprising a carbon nanotube wire and a solder portion connected to the wire. And a method of manufacturing a carbon nanotube wire.

  2. Description of the Related Art Conventionally, as a power line or signal line in various fields such as automobile and industrial equipment, a wire made of a core wire made of one or more wires and an insulation coating which covers the core wire is used. As a material of the wire which comprises a core wire, although a copper or copper alloy is usually used from a viewpoint of an electrical property, aluminum or an aluminum alloy is proposed from a viewpoint of weight reduction in recent years. For example, the specific gravity of aluminum is about 1/3 of the specific gravity of copper, and the conductivity of aluminum is about 2/3 of that of copper (based on 100% IACS for pure copper, about 66% IACS for pure aluminum) There is a need to increase the cross-sectional area of the aluminum wire to about 1.5 times the cross-sectional area of the copper wire in order to pass the same current as the copper wire to the aluminum wire. Even if the increased aluminum wire is used, since the mass of the aluminum wire is about half of the mass of the pure copper wire, using the aluminum wire is advantageous from the viewpoint of weight reduction.

  With the above background, in recent years, the performance and functionality of automobiles, industrial equipment, etc. are being promoted, and along with this, the number of installation of various electric devices, control equipment, etc. increases. The number of electrical wiring lines used in these devices also tends to increase. On the other hand, in order to improve the fuel consumption of a mobile body such as a car for environmental protection, weight reduction of the wire is strongly desired.

  As one of the new means for achieving such further weight reduction, a technology of utilizing carbon nanotubes as a wire is newly proposed. A carbon nanotube is a single layer of a tubular body having a network structure of a hexagonal lattice, or a three-dimensional network structure composed of multiple layers arranged substantially coaxially, and is lightweight, and also has conductivity, current capacity, Because of their excellent properties such as elasticity and mechanical strength, they are attracting attention as a material to replace metals used for power lines and signal lines.

The specific gravity of carbon nanotubes is about 1/5 of the specific gravity of copper (about 1/2 of aluminum), and carbon nanotubes alone are higher than copper (resistivity 1.68 × 10 ^-6 Ω · cm) It shows conductivity. Therefore, theoretically, by forming a carbon nanotube assembly by twisting a plurality of carbon nanotubes, further weight reduction and high conductivity can be realized. However, when carbon nanotubes in μm to mm units are produced by twisting carbon nanotubes in nm units, the outer diameter per one unit, which is a constituent unit, is very small, so the contact resistance between carbon nanotubes and internal defects It is difficult to use the carbon nanotube as a wire as it is because the formation is a factor and the resistance value of the whole wire is increased. In addition, from the viewpoint of connection, when a carbon nanotube connection structure composed of a carbon nanotube wire and a solder is produced, the compatibility between the carbon nanotube wire and the solder is poor, and it is difficult to secure connection strength and electrical characteristics.

  The CNT is grown by CVD (chemical vapor deposition) or the like at the end of the carbon nanotube twisted wire (wire material), and the grown CNT extended from the end is connected to another carbon nanotube twisted wire or its grown CNT to obtain carbon. There has been proposed a manufacturing method capable of realizing the connection strength and the electrical characteristics of nanotube twisted wires (Patent Document 1).

JP, 2013-47402, A

  However, in the above-mentioned patent documents, it is only disclosed to connect the end parts of the carbon nanotube wire which twists a plurality of carbon nanotubes together via growth CNT. A carbon nanotube wire made by twisting carbon nanotube bundles has a problem that contact resistance between carbon nanotube bundles is high and current concentrates on a specific carbon nanotube bundle, so-called overcurrent easily occurs.

  An object of the present invention is to provide a carbon nanotube wire and a carbon nanotube connection structure capable of reducing the contact resistance between carbon nanotube bundles and suppressing the generation of an overcurrent.

The essential features of the present invention are as follows.
[1] A carbon nanotube wire constituted by twisting a plurality of carbon nanotube bundles,
And a plating unit provided along the longitudinal direction of the carbon nanotube wire, and disposed on the inner portion and the surface portion of the carbon nanotube wire.
In a cross section in a direction perpendicular to the longitudinal direction of the carbon nanotube wire, a ratio of a length of a portion where a plating layer with a thickness of 1 μm or more is formed on the surface of the carbon nanotube bundle to the entire surface of the carbon nanotube bundle is 0. A carbon nanotube wire characterized in that a ratio of a value obtained by dividing the number of carbon nanotube bundles having 5 or more by the total number of the plurality of carbon nanotube bundles is 70% or more.
[2] The carbon nanotube wire according to [1], wherein the plating portion is three-dimensionally formed between a plurality of adjacent carbon nanotube bundles among the plurality of carbon nanotube bundles.
[3] The plated portion may be made of copper (Cu), silver (Ag), gold (Au), tin (Sn), platinum (Pt), titanium (Ti), iron (Fe), chromium (Cr) and nickel ( The carbon nanotube wire according to the above [1] or [2], which is formed of a material containing as a main component one or more selected from the group consisting of Ni).
[4] The carbon nanotube wire according to any one of the above [1] to [3], which is doped with a different element.
[5] The carbon nanotube wire according to any one of the above [1] to [4], wherein the carbon nanotube constituting the carbon nanotube wire has a layer structure of two layers or three layers.
[6] A carbon nanotube wire connected structure comprising: a carbon nanotube wire configured by twisting a plurality of carbon nanotube bundles; and a solder portion connected to the carbon nanotube wire,
The carbon nanotube wire is provided along the longitudinal direction of the carbon nanotube wire, and includes a plating unit disposed in the inside and the surface portion of the carbon nanotube wire.
The carbon nanotube having a ratio of a length of a portion where a plated portion having a thickness of 1 μm or more is formed on the surface of the carbon nanotube bundle to a total surface length of the carbon nanotube bundle in a cross sectional view of the carbon nanotube wire A carbon nanotube wire connected structure, wherein a ratio of a value obtained by dividing the number of bundles by the total number of the plurality of carbon nanotube bundles is 70% or more.
[7] A step of subjecting a carbon nanotube wire main body composed of a plurality of carbon nanotube bundles to electroless plating to form a base portion;
Subjecting the carbon nanotube wire main body subjected to the non-electrolytic plating treatment to electrolytic plating treatment to form a plated portion on the inside and the surface portion of the carbon nanotube wire main body along the longitudinal direction of the carbon nanotube wire main body; ,
Before the step of applying the electroless plating or after the step of applying the electrolytic plating, a step of twisting the plurality of carbon nanotube bundles together;
A method for producing a carbon nanotube wire, comprising:

  According to the present invention, the occurrence of overcurrent in the carbon nanotube wire can be reduced.

It is a schematic diagram which shows an example of a structure of the carbon nanotube wire which concerns on embodiment of this invention, (a) is a perspective view, (b) is sectional drawing. It is a sectional view showing an example of composition of a carbon nanotube wire rod connection structure concerning an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Configuration of carbon nanotube wire connection structure>
FIG. 1 is a schematic view showing an example of the configuration of a carbon nanotube wire according to an embodiment of the present invention, (a) is a perspective view, and (b) is a cross-sectional view. In addition, the carbon nanotube wire connection structure in FIG. 1 shows the example, and the shape of each structure based on this invention, a dimension, etc. shall not be restricted to the thing of FIG.

  As shown in FIGS. 1A and 1B, the carbon nanotube wire 1 (hereinafter, also referred to as a CNT wire) twists a plurality of carbon nanotube bundles 11, 11, ... (hereinafter, referred to as a CNT bundle) And a plating portion 12 provided along the longitudinal direction of the CNT wire 1 and disposed on the inside and the surface layer of the CNT wire, and a direction perpendicular to the longitudinal direction of the CNT wire 1 In the cross section of the cross section, the number of CNT bundles having a ratio of the length of a portion where a plated portion having a thickness of 1 μm or more is formed on the surface of the CNT bundle to the entire surface length of the CNT bundle 11 is 0.5 or more The ratio of the value divided by the total number of CNT bundles 11, 11, ... is 70% or more.

  The plating unit 12 is preferably formed three-dimensionally between a plurality of adjacent CNT bundles among the plurality of CNT bundles 11, 11,. For example, the plating unit 12 has a three-dimensional structure formed in communication between the plurality of CNT bundles 11, 11,. Further, it is preferable that a part of the plating part 12 be disposed as a plating layer on a part or the whole of the outer peripheral surface of each CNT bundle 11.

  The plating portions 12 are preferably evenly distributed over the entire CNT wire 1 in a cross section in a direction perpendicular to the longitudinal direction of the CNT wire 1, and are uniformly distributed. In FIG. 1, the plating unit 12 is separately formed on the surface of the plurality of CNT bundles 11, but may be integrally formed on the surface of the plurality of CNT bundles 11, 11,. In addition, the plating portion 12 is preferably formed between a plurality of adjacent CNTs, for example, between two adjacent CNTs 11 and 11. Furthermore, the plating portion 12 is more preferably formed in close contact with any one of the plurality of adjacent CNTs.

  The plating part is copper (Cu), silver (Ag), gold (Au), tin (Sn), platinum (Pt), titanium (Ti), iron (Fe), from the viewpoint of compatibility between the solder and the CNT wire 1. It is preferable to be formed of an alloy mainly composed of one or more selected from the group consisting of chromium (Cr) and nickel (Ni).

  The CNT wire 1 may have another metal part other than the plating part 12. For example, the CNT wire 1 is made of copper (Cu), silver (Ag), gold (Au), tin (Sn), platinum (Pt), titanium (Ti), iron (Fe), chromium (Cr) and nickel (Ni) A plated portion made of an alloy mainly composed of one or more selected from the group consisting of and an underlayer of the plated portion, and iron (Fe), nickel (Ni) and cobalt (Co) or these And a base portion formed of an alloy containing as a main component. The base portion is preferably formed by plating, and in this case, constitutes another plated portion different from the above-described plated portion. Moreover, when both a plating part and a base part are formed in the CNT wire 1, a part of base part is formed in the outer surface of the CNT bundle 11, and a part of plating part is formed in the outer surface of a base part. Is preferred. At this time, it is possible to use the first layer located on the inner side as viewed from the center of gravity of the CNT bundle 11 as the first layer and the second formed layer on the outer side. Furthermore, when both a plating part and a base part are formed in the CNT wire 1, the multilayer of the said base part may be provided, and the multilayer of the said plating part may be formed. By providing the base portion on the CNT wire 1 or the CNT bundle 11, the wettability between the base portion and the plating can be improved, and the adhesive strength between the CNT wire 1 and the plating portion 12 can be improved.

  The thickness of the plating unit 12 is 0.3 μm to 3.0 μm in consideration of the protection of the base material, the cost, and the like. When both the plated part and the base part are formed, the total thickness of the plated part and the base part is 0.3 μm to 3.0 μm. At this time, the material of the base portion corresponding to the first layer of the CNT bundle is a metal excellent in adhesion to the CNT bundle, and the material of the plating portion corresponding to the second layer is a metal excellent in electric conduction. Is preferred.

  In the stranded wires of carbon nanotubes or carbon nanotube bundles, the connection resistance is large between unplated strands, and conduction between the strands is difficult. Therefore, when current flows from the terminal, current may not flow to all strands constituting the stranded wire, and particularly when large current flows, current flows only to a specific strand, and the allowable current of the strand If the amount is exceeded, the wire may be cut.

  When the strands which are CNT bundles are plated, the plated strands are not plated with the plated strands by about 1/100 as compared to unplated strands and strands. In the case of the strands, the contact resistance is lowered to about 1/10, so that the conduction between the strands is improved, and the current flows in the entire strands. As a result, even when a large current flows, an excess current does not flow in a specific strand and the strand is not cut.

  Therefore, in the present embodiment, in the cross section in the direction perpendicular to the longitudinal direction of the CNT wire 1, the length of the portion where the plated portion with a thickness of 1 μm or more is formed on the outer edge of the CNT bundle The value obtained by dividing the number of CNT bundles having a ratio of 0.5 or more by the total number of CNT bundles 11, 11, ... is 70% or more, preferably 80% or more, and more preferably 90% or more. preferable. If the above value is less than 70%, the contact resistance between the strands is not sufficiently lowered, and when a large current flows, an overcurrent tends to be generated in the strands of the characteristics, which is not preferable. In addition, if the thickness of the plated portion formed on the outer edge of the CNT bundle is less than 1 μm, the plating peels off during soldering and the CNTs are exposed, which is not preferable because the connection resistance increases.

  When the cross section of each CNT bundle is circular or the equivalent circle diameter can be calculated, in the cross section in the direction perpendicular to the longitudinal direction of the CNT wire 1, the thickness of the outer periphery of the CNT bundle 11 is The ratio of the value obtained by dividing the number of carbon nanotube bundles having a length ratio of 0.5 or more of the length of the portion where the plating layer of 1 μm or more is formed by the total number of the plurality of carbon nanotube bundles 11, 11,. Is 70% or more, preferably 80% or more, and more preferably 90% or more.

  The plating portion 12 may be formed on a part of the entire length of the CNT wire 1 in the longitudinal direction, or may be formed over the entire length of the CNT wire 1 in the longitudinal direction. In the plating unit 12, the number of CNT bundles in which the ratio of the length of the portion where the plating layer having a thickness of 1 μm or more is formed at the outer edge of the CNT bundle to the entire outer edge length of the CNT bundle 11 is 0.5 or more. It is preferable that the ratio of the value divided by the total number of the plurality of CNT bundles 11, 11... Has a small variation in the longitudinal direction of the CNT wire 1. For example, a 1.0 m CNT wire is cut at approximately 10 locations, each cross section is observed by SEM, the above value of each CNT bundle is calculated using the above calculation method, and the obtained plurality of values are averaged. Thus, an average value of the above values in the longitudinal direction of the plating portion 12 can be obtained. Moreover, the dispersion | variation in the said value regarding the longitudinal direction of the CNT wire 1 can be confirmed by calculating | requiring the standard deviation of the said value obtained by ten places.

The CNT wire 1 is configured by twisting together CNT bundles in which a plurality of CNTs having a layer structure of one or more layers are bundled. The outer diameter of the CNT wire 1 is 0.01 mm to 5 mm.
The CNT wire 1 is a bundle body in which a plurality of CNTs are put together. The CNT wire 1 may be doped with different elements. In this case, a plurality of carbon nanotube complexes in which different kinds of elements are doped into the CNT bundle 11 may be twisted together.

  The CNTs constituting the CNT wire 1 are cylindrical bodies having a single layer structure or a multilayer structure, and are respectively called SWNT (single-walled nanotubes) and MWNT (multi-walled nanotubes). For example, a CNT having a two-layer structure is a three-dimensional network structure in which two cylindrical bodies having a network structure of a hexagonal lattice are arranged substantially coaxially and is called DWNT (Double-walled nanotube). The hexagonal lattice, which is a structural unit, is a six-membered ring having a carbon atom at its apex, and adjacent to another six-membered ring, these are continuously bonded.

  The properties of CNTs depend on the chirality of the cylinder as described above. The chirality is roughly classified into an armchair type, a zigzag type, and other chiral types. The armchair type is metallic, the chiral type is semiconductive, and the zigzag type shows an intermediate behavior. Therefore, the conductivity of CNTs largely differs depending on which chirality it has, and in order to improve the conductivity of the CNT assembly, it is important to increase the proportion of armchair-type CNTs exhibiting metallic behavior. The On the other hand, it is known that metallic behavior is exhibited by doping a chiral type CNT having a semiconducting property with a substance having an electron donating property or an electron accepting property (different element). In addition, in general metals, the doping of different elements causes scattering of conduction electrons inside the metal to lower the conductivity, but in the same way, when metallic CNTs are doped with different elements, , Cause a decrease in conductivity.

  As described above, it can be said that the doping effect on metallic CNTs and semiconducting CNTs is in a trade-off relationship from the viewpoint of conductivity, so theoretically, metallic CNTs and semiconducting CNTs are separately prepared. It is desirable to combine these after treating only semiconducting CNTs with doping treatment. However, it is difficult to selectively make metallic CNTs and semiconducting CNTs selectively with the current manufacturing method technology, and metallic CNTs and semiconducting CNTs are produced in a mixed state. For this reason, in order to improve the conductivity of a CNT wire made of a mixture of metallic CNT and semiconducting CNT, it is preferable to select a CNT structure in which doping treatment with different elements and molecules is effective.

The CNTs constituting the CNT wire 1 preferably have a layer structure of two layers or three layers. Specifically, in the CNT bundle 11 constituting the CNT wire 1, the ratio of the sum of the number of CNTs having a two-layer structure or a three-layer structure to the number of CNTs is preferably 50% or more. More preferably, it is at least%. That is, the total number of all CNTs constituting one CNT bundle is N _TOTAL , the sum of the number of CNT (2) having a two-layer structure among all the CNTs is N _{CNT (2)} , a three-layer structure among all the CNTs When the sum of the numbers of CNTs (3) having N is N _{CNT (3)} , it can be represented by the following formula (1).
(N _{CNT (2)} + N _{CNT (3)} ) / N _TOTAL × 100 (%) 50 50 (%) ... (1)

  CNTs with fewer layers, such as a two-layer or three-layer structure, are relatively more conductive than CNTs with more layers. In addition, the dopant is introduced into the innermost layer of the CNTs or in the interstices formed between the plurality of CNTs. The interlayer distance of CNTs is equivalent to 0.335 nm, which is the interlayer distance of graphite, and in the case of multi-walled CNTs, it is difficult for the dopant to penetrate between the layers in size. From this, the doping effect is expressed by the introduction of a dopant into the inside and outside of the CNT, but in the case of multi-walled CNT, the doping effect of the tube located inside not in contact with the outermost layer and the innermost layer is less easily expressed. . For the reasons as described above, when the multi-layered CNTs are respectively doped, the doping effect of the double-layered or triple-layered CNTs is the highest. Also, the dopant is often a highly reactive reagent that exhibits strong electrophilicity or nucleophilicity. The single-layered CNT is less rigid than the multi-layered structure, and the chemical resistance of the single-layered CNT is inferior to that of the multi-layered one. Therefore, in the present invention, attention is focused on the number of CNTs having a two-layer structure or a three-layer structure included in the CNT assembly. In addition, if the ratio of the sum of the number of CNTs having a two-layer or three-layer structure is less than 50%, the ratio of CNTs having a single-layer structure or a multilayer structure of four or more layers becomes high, and doping as a whole CNT assembly The effect is reduced and it is difficult to obtain high conductivity. Therefore, the ratio of the sum of the number of CNTs having a two-layer or three-layer structure is set to a value within the above range.

  The dopant doped into the CNT is not particularly limited as long as the conductivity is improved, but one or more different elements selected from the group consisting of nitric acid, sulfuric acid, iodine, bromine, potassium, sodium, boron and nitrogen or It is a molecule.

  Moreover, it is preferable that the outer diameter of the outermost layer of CNT which comprises the CNT bundle | flux 11 is 5.0 nm or less. When the outer diameter of the outermost layer of the CNTs constituting the CNT bundle 11 exceeds 5.0 nm, the porosity resulting from the gaps between the CNTs and the innermost layer becomes large, and the conductivity is unfavorably reduced.

  The CNT wire 1 may have another metal member dispersedly disposed in the wire in terms of the strength and conductivity of the entire wire. Other metal members are, for example, elongated wires or particles, and other metal members having such a shape are mixed with CNTs. The metal of the said other metal member is a material which has copper, a copper alloy, aluminum, and an aluminum alloy as a main component, for example.

<Method of manufacturing carbon nanotube wire>
The method of manufacturing a carbon nanotube wire according to the present embodiment comprises the steps of subjecting a carbon nanotube wire main body composed of a plurality of carbon nanotube bundles to electroless plating, and the carbon nanotube wire main body subjected to the electroless plating. The step of forming a plating portion on the inside and the surface layer portion of the carbon nanotube wire rod body along the longitudinal direction of the carbon nanotube wire rod body by performing a plating process, or before the step of applying the electroless plating or the electric field After the step of plating, the step of twisting the plurality of carbon nanotube bundles.

  Specifically, first, a CNT wire main body composed of a plurality of CNT bundles is prepared, and an alloy mainly composed of one or more selected from iron (Fe), nickel (Ni) and cobalt (Co) is selected. It is immersed in the plating bath to be contained for a predetermined time to form a base portion to be a base of the plating portion in the CNT wire main body. Thereby, a base part is formed in the inside and surface part of a CNT wire. By forming the base portion on the CNT wire main body, the adhesion between the CNT wire main body and the plated portion can be improved.

  Next, the CNT wire body on which the base portion is formed is made of copper (Cu), silver (Ag), gold (Au), tin (Sn), platinum (Pt), titanium (Ti), iron (Fe), chromium The plating portion is formed in the CNT wire main body by immersing for a predetermined time in a plating bath containing an alloy composed mainly of one or more selected from the group consisting of (Cr) and nickel (Ni). Thereby, a plating part is formed in the inside and surface layer part of a CNT wire. By this electroplating process, the CNT wire in which the plating part was formed in the inside and surface layer part of a CNT wire is obtained.

  The ratio in the depth direction of the plated portion formed by the electroless plating or electrolytic plating process, that is, the ratio of the thickness of the plated portion to the length from the outer edge to the center of gravity of the CNT wire corresponds to the twist degree of the plurality of CNT bundles. Dependent. In order to set the ratio in the depth direction of the plated portion to a value within a preferable range, a step of twisting a plurality of CNT bundles after the step of applying the electroless plating, or a step of applying the electroless plating is performed Preferably, the step of twisting the plurality of CNT bundles with weak twist is performed. When performing the step of twisting before the step of applying electroless plating, plating of the plating bath can be performed by reducing the twist degree (T / m) representing the number of turns per unit length of the CNT wire body. In addition to the CNT bundle located in the surface layer portion of the CNT wire, the plating portion can be formed also in the CNT bundle located inside the CNT wire.

  Next, the plurality of carbon nanotube bundles on which the base portion and the plating portion are formed are twisted. Thereby, the CNT wire 1 provided with the plating part 12 mainly distribute | arranged to the surface layer part 1a is obtained.

<Configuration of carbon nanotube wire connection structure>
FIG. 2: is sectional drawing which shows an example of a structure of the carbon nanotube wire rod bonded structure which concerns on this embodiment. The carbon nanotube wire connection structure shown in FIG. 2 is an example thereof, and the shape, dimensions, and the like of each component according to the present invention are not limited to those shown in FIG.
As shown in FIG. 2, a carbon nanotube wire rod bonded structure 10 (hereinafter also referred to as a CNT wire rod bonded structure) comprises a CNT wire rod 1 formed by twisting a plurality of CNT bundles 11, And a solder portion 2 connected to the CNT wire 1. The solder portion 2 is connected to the CNT wire 1 via the plating portion 12 and connected to a connection member 20 such as a copper plate.

  The solder portion 2 is, for example, an alloy mainly composed of one or more selected from copper (Cu), tin (Sn), lead (Zn), silver (Ag), nickel (Ni) and chromium (Cr). It is formed. The solder portion 2 can be formed, for example, by a reflow method or a method using a filiform solder and a soldering iron.

  The solder portion 2 is provided along the longitudinal direction of the CNT wire 1 in the same manner as the plating portion 12 and is disposed in the inside and the surface layer portion of the CNT wire 1. As described above, in the cross-sectional view of the carbon nanotube wire, the plating unit 12 has a length of a portion where a plating unit with a thickness of 1 μm or more is formed on the surface of the carbon nanotube bundle with respect to the entire surface length of the carbon nanotube bundle. The ratio of the value obtained by dividing the number of carbon nanotube bundles having a ratio of 0.5 or more by the total number of the plurality of carbon nanotube bundles 11, 11, ... is 70% or more. And the solder part 2 is joined with the plating part 12 distribute | arranged to the above-mentioned ratio in the inside and surface layer part of the CNT wire rod 1. As shown in FIG. Thereby, the solder part 2 and the plating part 12 adhere | attach favorably, and the mechanical connection and the electrical connection of the solder part 2 and the CNT wire 1 are ensured.

  In FIG. 1, the solder portion 2 is formed on the entire surface of the plating portion 12 disposed on the surface layer portion 1 a of the CNT wire 1 in a cross-sectional view in a direction perpendicular to the longitudinal direction of the CNT wire 1. As long as good connectivity with 1 can be secured, it may be formed in part of the plating unit 12. In addition, although the solder portion 2 is formed on the entire surface of the surface layer portion 1 a of the CNT wire 1, the solder portion 2 may be a part of the surface layer portion 1 a of the CNT wire 1 within a range where good connectivity with the CNT wire 1 can be secured. It may be formed.

  As described above, according to the present embodiment, the CNT wire 1 is provided with the plating portion 12 provided along the longitudinal direction of the CNT wire and disposed in the inner portion and the surface layer portion of the CNT wire 1, and the CNT wire In the cross section in the direction perpendicular to the longitudinal direction of 1, the ratio of the length of the portion where the plated portion with a thickness of 1 μm or more is formed on the surface of the CNT bundle is 0.5 or more Since the ratio of the value obtained by dividing the number of carbon nanotube bundles by the total number of CNT bundles 11, 11, ... is 70% or more, the contact resistance between the CNT bundles is reduced by the interposition of the plating unit 12, A current can be supplied to substantially all of the plurality of CNT bundles 11, 11,... Constituting the CNT wire 1. Thereby, the contact resistance between the CNT bundles can be reduced, and the occurrence of an overcurrent can be suppressed.

  In addition, the CNT wire connection structure 10 includes a CNT wire 1 configured by twisting a plurality of CNT bundles 11, 11, ..., and a solder portion 2 connected to the CNT wire 1, and the solder portion 2 However, since it is connected with the CNT wire 1 via the plating part 12, it becomes possible to realize a good connection between the CNT wire 1 and the connected member 20.

  As mentioned above, although the CNT wire material concerning embodiment of this invention, the CNT connection structure, and its manufacturing method were described, this invention is not limited to the embodiment of the description, Based on the technical thought of this invention, various kinds Variations and modifications are possible.

  Hereinafter, examples of the present invention will be described.

(Example 1 and Comparative Example 1)
First, decahydronaphthalene as a carbon source, ferrocene as a catalyst, ferrocene as a catalyst, inside an alumina tube with an inner diameter of 60 mm and a length of 1600 mm heated to 1300 ° C. by an electric furnace using floating catalyst vapor phase growth (FCCVD) A raw material solution L containing thiophene as a reaction accelerator at a volume ratio of 100: 4: 1 was supplied by spray spraying. The carrier gas was supplied with hydrogen at 9.5 L / min. The obtained CNTs are collected in a sheet form by a collection machine, collected and collected to produce a CNT assembly, and further, the CNT assembly is bundled to produce a CNT wire, which is heated to 500 ° C. in the atmosphere, and further acid The purification was performed by treatment.
After 50 mg of the obtained CNTs and 450 mg of sodium cholate were added to 24.5 g of water and stirred for 30 minutes using an ultrasonic stirrer, a dispersion was obtained using an ultrasonic homogenizer. Subsequently, the CNT dispersion was injected into isopropyl alcohol through an injection nozzle with an inner diameter of 1 mm, coagulated in a thread, and dried to obtain a 3 m strand of CNT.
The obtained strand was immersed in a plating solution consisting of copper sulfate, formalin and Rochelle salt, and electroless copper plating was performed. Thereafter, the CNT wire main body was immersed in a plating solution composed of an aqueous solution of copper sulfate and sulfuric acid, and electrolytic plating was performed for 50 minutes at 1A, to produce 38 strands of electrolytically plated wire.
Subsequently, 38 copper-plated wires were twisted at 200 T / m to obtain a CNT wire which is a CNT stranded wire in which 100% of the wires are copper-plated.
(Example 2)
A strand produced in the same manner as in Example 1 was twisted at 10 T / m.
The CNT wire body was immersed in a plating solution consisting of copper sulfate, formalin and Rochelle salt, and electroless copper plating was performed.
Thereafter, the CNT wire main body was immersed in a plating solution composed of an aqueous solution of copper sulfate and sulfuric acid, and electrolytic plating was performed for 40 minutes at 1A to fabricate a CNT wire having the CNT wire main body subjected to electrolytic plating treatment.

(Comparative example 1)
Nineteen non-copper-plated strands and nineteen copper-plated strands produced in the same manner as in Example 1 were twisted at 200 T / m to obtain a CNT wire which is a CNT stranded wire.

(A) Measurement of Plating Ratio A 1.0 m CNT stranded wire (CNT wire) was cut at a plane perpendicular to the longitudinal direction every 10 cm, and the cross section was polished by ion milling. Subsequently, SEM observation was performed. The total length of the surface of each strand of the CNT wire was determined and designated as A. Subsequently, the length of the plated portion of the surface of the wire is B. A wire having a B / A of 0.5 or more was used as the wire on which the plated portion was formed, and the number of wires was determined.
The ratio of the value obtained by dividing the number of strands in which the plated portion was formed as described above by the total number of strands of the entire CNT wire was taken as the plating ratio (%) in the cross section of the CNT wire. The case where the plating ratio was 70% or more was regarded as good.

(B) Bondability with Solder The end of the CNT stranded wire and the copper plate were connected by solder to prepare a CNT connection structure in which a solder portion was formed, and the connection resistance between the copper plate and the CNT stranded wire was measured. . The case where the connection resistance is 10 mΩ or less is considered to be good.

(C) Measurement of presence or absence of overcurrent A current was applied to the twisted CNT wires at a current density of 2000 A / cm ² for 5 minutes. The resistance value of the twisted CNT wire before current flow was R1, and the resistance value after current flow was R2. When an overcurrent occurs, R2 has a higher value than R1 because a specific strand deteriorates. Here, the case where R2 / R1 <1.5 is regarded as good “○”, and the case where R2 / R1 ≧ 1.5 is regarded as defect “x”.

(D) Density of CNT Stranded Wire The density of the CNT stranded wire was measured using a density gradient tube. A sample with a length of 2 cm in the longitudinal direction was used. When the density of the CNT stranded wire is less than 2.7 g / cm ³ equivalent to the density of aluminum, it is regarded as good as a lightweight electric wire.

  The measurement and evaluation results of Example 1 and Comparative Example 1 are shown in Table 1.

  As shown in Table 1, in Examples 1 and 2, a plated portion was provided on the inside and the outermost layer of the CNT wire, and the plating ratio in the CNT wire was good at 100% and 82%, respectively. Moreover, it turned out that generation | occurrence | production of an overcurrent is suppressed and it is excellent in durability. Moreover, it turned out that both the bondability with a solder and the density of CNT stranded wire are favorable.

  On the other hand, in Comparative Example 1, it was found that the above-mentioned plating ratio in the CNT wire was poor, an overcurrent was frequently generated, and the durability of the CNT wire was low. In addition, it was found that the connection resistance was much larger than those of Examples 1 and 2.

1 Carbon nanotube wire (CNT wire)
2 solder part 10 carbon nanotube wire connection structure (CNT wire connection structure)
11 Carbon nanotube bundle (CNT bundle)
12 plated portion 20 connected member

Claims (7)

A carbon nanotube wire constituted by twisting a plurality of carbon nanotube bundles,
And a plating unit provided along the longitudinal direction of the carbon nanotube wire, and disposed on the inner portion and the surface portion of the carbon nanotube wire.
In a cross section in a direction perpendicular to the longitudinal direction of the carbon nanotube wire, a ratio of a length of a portion where a plating layer with a thickness of 1 μm or more is formed on the surface of the carbon nanotube bundle to the entire surface of the carbon nanotube bundle is 0. A carbon nanotube wire characterized in that a ratio of a value obtained by dividing the number of carbon nanotube bundles having 5 or more by the total number of the plurality of carbon nanotube bundles is 70% or more.   The carbon nanotube wire according to claim 1, wherein the plating portion is three-dimensionally formed between a plurality of adjacent carbon nanotube bundles among the plurality of carbon nanotube bundles.   The plating portion is made of copper (Cu), silver (Ag), gold (Au), tin (Sn), platinum (Pt), titanium (Ti), iron (Fe), chromium (Cr) and nickel (Ni). The carbon nanotube wire according to claim 1 or 2, wherein the carbon nanotube wire is formed of a material mainly composed of one or more selected from the group consisting of   The carbon nanotube wire according to any one of claims 1 to 3, wherein different types of elements are doped.   The carbon nanotube wire according to any one of claims 1 to 4, wherein the carbon nanotube constituting the carbon nanotube wire has a layer structure of two layers or three layers. A carbon nanotube wire connection structure comprising: a carbon nanotube wire configured by twisting a plurality of carbon nanotube bundles; and a solder portion connected to the carbon nanotube wire,
The carbon nanotube wire is provided along the longitudinal direction of the carbon nanotube wire, and includes a plating unit disposed in the inside and the surface portion of the carbon nanotube wire.
The carbon nanotube having a ratio of a length of a portion where a plated portion having a thickness of 1 μm or more is formed on the surface of the carbon nanotube bundle to a total surface length of the carbon nanotube bundle in a cross sectional view of the carbon nanotube wire A carbon nanotube wire connected structure, wherein a ratio of a value obtained by dividing the number of bundles by the total number of the plurality of carbon nanotube bundles is 70% or more. Subjecting a carbon nanotube wire main body composed of a plurality of carbon nanotube bundles to electroless plating to form a base portion;
Subjecting the carbon nanotube wire main body subjected to the non-electrolytic plating treatment to electrolytic plating treatment to form a plated portion on the inside and the surface portion of the carbon nanotube wire main body along the longitudinal direction of the carbon nanotube wire main body; ,
Before the step of applying the electroless plating or after the step of applying the electrolytic plating, a step of twisting the plurality of carbon nanotube bundles together;
A method for producing a carbon nanotube wire, comprising:

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