WO2011009477A1

WO2011009477A1 - Cable containing oriented nanoparticles

Info

Publication number: WO2011009477A1
Application number: PCT/EP2009/005624
Authority: WO
Inventors: Jörg FINDEISEN
Original assignee: Siemens Aktiengesellschaft
Priority date: 2009-07-23
Filing date: 2009-07-23
Publication date: 2011-01-27

Abstract

The invention relates to, among other things, a cable (10) having at least one electrical conductive conductor (20, 100, 110, 120) extending in the longitudinal direction of the cable and an insulation material (30), in which the conductor is embedded. According to the invention, the electrically conductive conductor comprises nanoparticles (40, 50), which are oriented in the longitudinal direction of the cable, and further nanoparticles (60) oriented perpendicularly to the longitudinal direction of the cable are present.

Description

Description The invention relates to a cable having at least one electrically conductive conductor extending in the cable longitudinal direction and an insulating material in which the conductor is embedded. Such cables are used for example in the field of electrical Energieubertragungstechmk.

The invention is based on the object of specifying a cable that has better electrical and mechanical properties than previous cables.

This object is achieved according to the invention by a cable with the features according to claim 1. Advantageous embodiments of the cable according to the invention are specified in subclaims.

Thereafter, it is provided according to the invention that the electrically conductive conductor comprises nanoparticles which are aligned in the cable longitudinal direction and, in addition, further nanoparticles are present which are oriented transversely to the cable longitudinal direction.

A significant advantage of the inventive cable is that it has both very good electrical and very good thermal properties. The electrical properties are brought about by the nanoparticles provided in the electrically conductive conductor, which are aligned in the cable length direction. Due to the orientation of the nanoparticles along the cable length direction, the electrical conductivity is improves the conductivity of the conductor and thus reduces its electrical resistance. This also leads to a reduction of the heat generated in the cable. Another essential advantage of the cable according to the invention consists in the heat removal caused by the further nanoparticles; The heat dissipation is effected by the fact that the other nanoparticles are aligned transversely to the cable length direction and selectively divert the heat generated in the or in the conductive conductors by the insulation material to the outside. Because of the nanoparticles oriented transversely to the cable longitudinal direction, the cable according to the invention thus has an optimized heat dissipation to the outside, so that it is more electrically resistant overall than previously known cables.

A third significant advantage of the cable according to the invention is that in this case the mechanical strength of the cable is markedly increased by the nanoparticles present. The cable according to the invention is thus mechanically significantly stronger and more resilient than comparable cables of the prior design with the same dimensioning and the same weight. Due to the increased mechanical strength and load capacity can be achieved with the erfj ndungsgemaßen cable thus significantly larger span widths between masts and support elements, as is possible with previous cables. The use of the inventive cable in electrical energy transmission systems thus leads to lower installation costs.

The nanoparticles are preferably elongate; By elongated nanoparticles are meant nanoparticles whose length is large, in particular at least 10 times greater than whose diameter is. Elongated nanoparticles are, for example, nanotubes, nanotubes or nanorods.

The nanoparticles can be single-walled, double-walled or multi-walled. The nanoparticles may, for example, be carbon nanotubes or carbon nanoneedles or boron nitride nanoparticles. The insulating material may for example consist of a plastic such as polyamide or a ceramic or contain at least one or more such materials.

The further nanoparticles, that is to say the nanoparticles oriented transversely to the cable length direction, are preferably located either exclusively in the insulating material or alternatively both in the insulating material and in the electrically conductive conductor.

The nanoparticles present in the conductor are predominantly (ie at least 50%, more preferably at least 75%) along the cable length direction and the nanoparticles present in the isolation material predominantly (ie at least 50%, particularly preferably at least 75%) across Aligned cable length direction. Alternatively or additionally, it may be provided that the electrically conductive conductor has-viewed in cross-section-at least one cross-sectional section in which the nanoparticles are oriented predominantly (ie at least 50%, particularly preferably at least 75%) in the cable longitudinal direction, and at least has a further cross-sectional portion in which the nanoparticles predominantly (ie at least 50%, more preferably at least 75%) are aligned transversely to the cable length direction. Particularly preferably, the electrically conductive conductor has a plurality in cross section Cross-sectional portions in which the nanoparticles are oriented predominantly in the cable longitudinal direction, and a plurality of further cross-sectional portions, in which the nanoparticles are oriented predominantly transversely to the cable length direction on.

The nanoparticles aligned in the cable length direction are preferably more electrically conductive than the other nanoparticles, ie the nanoparticles oriented transversely to the cable length direction, and / or the further nanoparticles oriented transversely to the cable length direction are preferably thermally more capable of being leached than the nanoparticles oriented along the cable length direction.

Incidentally, it is considered advantageous if the cable has at least two electrically conductive conductors and the conductors are arranged rotationally symmetrical.

For energy transmission in a three-phase energy transmission system, the cable preferably has three electrically conductive conductors, which are rotationally symmetrical with respect to the rotation angles of 120 degrees and 240 degrees.

In cross-section, a center is preferably present in the cable, and the other nanoparticles are preferably aligned radially outward with respect to this center.

It is also considered advantageous if the cable has an alignment structure extending at least in sections along the cable length direction, which - during the

Hersteilens of the cable or after the completion of the cable - allows an introduction of a field in the cable for aligning the other nanoparticles transverse to the cable length direction. Such an alignment structure is preferably a NEN electrically conductive or magnetizable center conductor, which extends along the Kabellangsrichtung and is located for example in the middle of the cable. To avoid local Felduberhohungen or Feldstarkespitzen, it is also considered advantageous if the at least one conductor has a Hullschicht which is on the side facing away from the conductor smoother than on the conductor facing the inside and / or consists of a semiconductor material or a semiconductor material at least also contains.

The semiconducting material and / or the insulating material may be vulcanizable, for example.

In order to achieve a current limitation in cable length direction and thus a protection of the cable against electrical overload, it is considered advantageous if the concentration of aligned in Kabellangsrichtung nanoparticles in the electrically conductive conductor along the Kabellangsrichtung is different and along the Kabellangsrichtung at least two different sized concentration ranges with nanoparticles oriented in the cable direction. This embodiment makes use of the knowledge that the electric current is primarily determined by the in

Nanoparticles oriented in the longitudinal direction will flow, so that a reduction in concentration will limit the current flow locally to a predetermined level, without increasing the electrical losses, at least not significantly.

It is also considered advantageous if the cable has a circular cross-sectional area and the conductor or conductors are arranged rotationally symmetrically and / or centrally within the round cross-sectional area. The cable may, for example, be an electrical power transmission cable designed and dimensioned for voltages of at least 100 V and currents of at least 1 A.

The invention also relates to a method of manufacturing a cable in which at least one electrically conductive conductor is embedded in an insulating material. According to the invention, it is provided that in the electrically conductive conductor nanoparticles are aligned in the cable longitudinal direction and further nanoparticles are aligned transversely to the cable longitudinal direction. With regard to the advantages of the method according to the invention, reference is made to the above statements in connection with the cable according to the invention, since the advantages of the cable according to the invention essentially correspond to those of the method according to the invention.

Particularly simple and thus advantageous, the other nanoparticles can be aligned transversely to the cable length direction by a field is applied to the cable. For example, the field may be applied between the conductors of the cable or between a conductor of the cable and an outer shield of the cable.

In order to enable the creation of a field which is independent of the arrangement of the conductors within the cable and can effect the desired alignment of the further nanoparticles, preferably in the cable along the cable length direction - at least in sections - an alignment structure is prepared and it is to this alignment structure a field with which the other nanoparticles are aligned transversely to the cable's direction.

The application of a field is preferably carried out as long as the insulation material of the cable is not yet fully cured, ie before or during the curing phase of the insulation material.

In order to achieve alignment of the further nanoparticles transversely to the cable slowing, alternatively or additionally, at least one growth seed can be used, which effects an alignment of the nanoparticles present in the insulation material during the application of the not yet cured, for example still liquid, insulating material Insulation material leads to an embedding of the nanoparticles with an orientation transverse to the cable length direction. For example, one of the conductors to be embedded in the insulation material can be used as a growth germ. Also, a conductor sleeve applied to the conductor or conductors can be used as a growth germ.

It is also possible for deliberately separate growth nuclei to be introduced into the cable during the manufacture of the cable, preferably into the insulation material, which leads to an embedding of the nanoparticles with an orientation transverse to the cable longitudinal direction. Preferably, a growth seed is provided in the cable center.

In order to bring about a current limitation in the cable, it is considered advantageous if the concentration of the nanoparticles aligned in the cable longitudinal direction in the electrically conductive conductor is varied along the cable longitudinal direction and at least two subdivisions along the cable longitudinal direction. different concentration ranges can be produced with nanoparticles aligned in the cable longitudinal direction.

The incorporation of the nanoparticles in the conductor and / or the incorporation of the further nanoparticles in the conductor and / or in the insulating material can be effected or assisted, for example, by electrophoresis. In this case, a co-ordination of different nanoparticles can be brought about by a coordination between the particle size and the pore width of a gel serving as the carrier medium, the gel serving as a molecular sieve. Also, by electrophoresis edges can be smoothed or shields formed.

To improve the heat dissipation to the outside, it is also considered advantageous if a rib structure or an oval-flattened outer shape of the or existing in the cable conductor is provided. Such a structure may, for example, be designed such that nanoparticles with good thermal conductivity and high electrical resistance are not only introduced into insulation of the cable but, moreover, arranged in such a way that they also take over the transport of the heat into these areas enlarging the surface , To achieve a moisture and / or dirt repellent surface of the cable, the formation of a nanoparticle-utilizing, dirt-repellent coating on the surface of the outer sheath of the cable is conceivable. For example, a nanoparticle-containing film or a nanoparticle-containing paint can be applied to the outside of the cable.

Moreover, it is considered advantageous if, by reducing the number of nanoparticles running parallel to the cable length direction, in a transition region with good thermal connection, the cable is protected against too high a short-circuit current.

The invention will be explained in more detail below with reference to exemplary embodiments; thereby show exemplarily:

1 shows a first exemplary embodiment of a cable according to the invention with a single electrical conductor, FIG.

FIG. 2 shows a second exemplary embodiment of a cable according to the invention with a single electrical conductor, the latter being provided with a jacket,

FIG. 3 shows an exemplary embodiment of an invention

Cable with three electrical conductors,

FIG. 4 shows an exemplary embodiment of an invention

Cable with three electrical conductors and an alignment structure for aligning the further nanoparticles,

5 shows a fifth exemplary embodiment of a cable according to the invention with three electrical conductors and a growth core which effects an alignment of the nanoparticles present in the insulating material of the cable during the production of the insulating material, FIG.

6 shows a sixth exemplary embodiment of a cable according to the invention with a conductor with nanotubes, FIG. 7 shows a seventh exemplary embodiment of a cable according to the invention with three conductive layers and three insulating layers, FIG. 8 shows an eighth exemplary embodiment of a cable according to the invention with two conductive layers and three insulating layers and

9 shows a ninth exemplary embodiment of a cable according to the invention with a matrix containing nanoparticles in the insulation.

For the sake of clarity, the same reference numerals are always used in the figures for identical or comparable components.

FIG. 1 shows an electrical cable 10 equipped with a single electrically conductive conductor 20. The conductor 20 is located in an insulating material 30, which consists of an electrically non-conductive material.

As can also be seen in FIG. 1, there are nanoparticles in the conductor 20 which are oriented predominantly, preferably at least 90%, in the cable length direction, that is to say in FIG. 1, perpendicular to the sheet direction. The direction of the nanoparticles is arbitrary: they can thus protrude perpendicular to the image plane in this or protrude from this. In the illustration according to FIG. 1, the nanoparticles designated by the reference numeral 40 project into the image plane, whereas the nanoparticles protrude with the reference numeral 50 from the image plane. In addition, it can be seen in FIG. 1 that there are further nanoparticles which are oriented predominantly, preferably at least 90%, transversely to the cable length direction and thus extend parallel to the image plane in FIG. The further nanoparticles are identified by the reference numeral 60; the further nanoparticles 60 are located exclusively in the insulation material 30 of the cable 10, but they may also be arranged-wholly or partially-in the conductor 20.

FIG. 2 shows a second exemplary embodiment of a cable 10. The cable according to FIG. 2 substantially corresponds to the cable according to FIG. 1. In contrast, only the electrical conductor 20 is enclosed with a hull layer, which is identified by the reference numeral 70. The function of the Hullschicht 70 is to make the electrical conductor to the outside smoother and thus avoid electrical Felduberhohungen. The hull layer 70 is thus preferably smoother on the outside 80 than on the inner side 90 facing the conductor 20. The hull layer 70 may consist, for example, of a semiconductor material.

In the figure 3 an embodiment of a cable 10 is shown that is equipped with three electrical conductors 100, 110 and 120. The arrangement of the three conductors 100, 110 and 120 is rotationally symmetric, so that the three conductors can be rotated by rotation angles of 120 degrees and / or 240 degrees, without changing their arrangement in the cable 10. It can also be seen from FIG. 3 that the three conductors 100, 110 and 120 are each provided with nanoparticles which, at least predominantly, extend perpendicularly to the image plane, ie project into the image plane or sticking out of this. The nanoparticles are identified by reference numerals 40 and 50.

The insulation material 30 of the cable 10 is also provided with nanotubes, but these extend transversely to the cable bell direction and thus lie in the image plane of FIG. The nanoparticles in the insulation layer 30, which are provided transversely to the cable length direction, are identified by the reference numeral 60.

Otherwise, the cable according to FIG. 3 corresponds to the cables in FIGS. 1 and 2.

FIG. 4 shows a fourth exemplary embodiment of a cable. This cable also has three electrical conductors 100 and 110 and 120 and corresponds to the exemplary embodiment according to FIG 3. In contrast to the exemplary embodiment of Figure 3, an additional alignment structure 200 is present, which has an electrically conductive or magnetizable center conductor 210, at least in sections extends along the Kabellangsrichtung and is preferably located in the middle of the cable. The alignment structure 200 makes it possible, during the production of the cable 10, in particular during application of the insulation material 30 or during curing of the insulation material 30, to cause an electric or magnetic field in the cable 10, with which the nanoparticles 60 present in the insulation material 30 are transverse to the cable longitudinal direction , ie parallel to the image plane, are aligned.

If, as shown, the center conductor 210 is located in the middle of the cable, a targeted radial or radial outward orientation of the nanoparticles 60 can be achieved. In other words, therefore, the alignment structure 200 with the electrically conductive or magnetizable center conductor 210 makes it possible to increase the concentration of the nanoparticles 60 oriented transversely to the cable line direction in the cable 10.

FIG. 5 shows a fifth exemplary embodiment of a cable 10. This cable is also equipped with three electrical conductors 100, 110 and 120. In the middle of the cable or between the three electrical conductors, there is a growth core 300, which effects targeted growth and / or targeted alignment of the nanoparticles 60 embedded in the insulation material 30 during cable production. Specifically, the growth core 300 causes the nanoparticles 60 to be oriented, preferably transversely to the cable length direction, while the insulation material 30 is applied and / or cured.

If, as shown, the growth core 300 is located in the center of the cable, then additionally a radial or

radially outward orientation of the nanoparticles 60 can be achieved.

For the rest, the exemplary embodiment according to FIG. 5 corresponds to the exemplary embodiment according to FIG. 3, so that in this regard reference should be made to the above statements.

FIG. 6 shows the combination of axial alignment of the carbon nanotubes for the power line and radial alignment of the carbon nanotubes for heat transport outward within the conductive conductor 20 of the cable 10. The reference numeral 51 represents the radially oriented carbon nanotubes in the conductor - lent to the remaining reference numerals, reference is made to the statements in connection with FIG.

FIGS. 7 and 8 show by way of example the adaptation of the concentration and orientation of nanotubes to the respective requirements.

In an advantageous embodiment, as shown in FIG. 7, the insulation is designed such that the dielectric constant decreases in the direction of decreasing electrical current

Field strength drops (or alternatively increases). This adaptation of the dielectric constant to the field requirements is at least partially made by adjusting the concentration and orientation of the nanotubes. The change in the concentration and orientation of the nanotubes can take place both in layers and continuously. Reference numerals 400, 410 and 420 show, by way of example, insulation layers with thermally conductive nanotubes, preferably extending transversely to the cable direction. Reference numerals 430, 440 and 450 denote layers of the conductive conductor having different concentrations of electroconductive carbon nanotubes or other current conducting nanotubes. The reference numeral 460 denotes a Hullschicht between the conductor and the insulating layers and the reference numeral 470 the jacket.

In a particular embodiment, radially aligned carbon nanotubes are used for heat removal, which are present in the direction of the conductor center facing only in a low concentration and their concentration increases to the outside. This allows the use of the good thermal conductivity of carbon nanotubes for heat dissipation. The intrinsically disadvantageous in the isolation electrical conductivity of conventional carbon nanotubes can be compensated by a low concentration in the areas of high electric field strength.

FIG. 8 shows an exemplary embodiment with two conductor regions 500 and 510 with different concentrations of conductive carbon nanotubes and insulation layers 520, 530 and 540 with different concentrations of thermally conductive carbon nanotubes or other thermally conductive nanotubes.

FIG. 9 shows by way of example a matrix with thermally conductive and / or electrically conductive nanotubes, for example carbon nanotubes or other nanotubes, in the insulation or the conductor of a cable. Designate

the reference numeral 600 carbon nanotubes for current transport (preferably axially aligned),

the reference numeral 610 nanotubes, so for example carbon nanotubes or other nanotubes, for heat transport (preferably radially aligned) and

- The reference numerals 620 and 630 carbon nanotubes to increase the mechanical strength (alignment according to the respective strength requirement). The carbon nanotubes with the reference numeral 620 are, for example, circularly aligned fuel nanotubes, which support the creation of a mechanically strong belt structure for forming a cable sheath.

In summary, the exemplary embodiments according to FIGS. 6 to 9 have in common that a cable is formed by a matrix of different materials which at least partially contain nanotubes of various electrical, thermal and mechanical properties. This can take into account: an adaptation of the concentration of carbon nanotubes to the current density required in the respective region of the cable and / or conductor,

an adjustment of the degree of alignment of the carbon nanotubes to those in the respective region of the cable and / or

Conductor's required current density,

an adaptation of the concentration of the thermally conductive nanotubes to the required heat flow density in the respective region of the arrangement,

an adaptation of the degree of alignment of the nanotubes to the heat flow density required in the respective region of the arrangement,

incorporation of nanotubes of particular mechanical properties (e.g., tensile strength) in certain areas (e.g., to absorb tensile forces when used as a conductor);

a formation of mechanical clamping elements by introducing a nanotube staggered belt structure for receiving short-circuit forces and / or transmission of the weight to mechanical fasteners and / or to form a solid and stable sheath of the cable.

reference numeral

10 electrical cable

20 electrically conductive conductor 30 insulation material

40.50 nanoparticles

51 carbon nanotubes

60 more nanoparticles

70 coating layer

80 outside

90 inside

100,110,120 electrical conductors

200 alignment structure

210 center conductors

300 growth core

400,410,420 insulation layer

430,440,450 layer

460 coating layer

470 coat

500,510 conductor area

520,530,540 insulation layer

600 carbon nanotubes

610 nanotubes

620, 630 carbon nanotubes

Claims

claims

A cable (10) having at least one electrically conductive conductor (20, 100, 110, 120) extending in the cable longitudinal direction and an insulating material (30) in which the conductor is embedded,

d a d u r c h e c e n c i n e s that

the electrically conductive conductor comprises nanoparticles (40, 50) which are aligned in the cable longitudinal direction and - in addition, further nanoparticles (60) are present, which

are aligned transversely to the cable length direction.

2. Cable according to claim 1,

d a d u r c h e c e n c i n e s that

the further nanoparticles are in the insulating material or both in the insulating material and in the electrically conductive conductor.

3. Cable according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the cable has at least two electrically conductive conductors and

the conductors are arranged rotationally symmetrical.

4. Cable according to claim 3,

d a d u r c h e c e n c i n e s that

the cable has three electrically conductive conductors (100, 110, 120), and

the conductors are arranged rotationally symmetrical with respect to the rotation angle of 120 degrees and 240 degrees.

5. Cable according to one of the preceding claims,

characterized in that the cable viewed in cross-section has a center and the other nanoparticles are aligned with respect to this center radially outward.

6. Cable according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the cable has an alignment structure (200) extending at least in sections along the cable direction, which makes it possible to introduce a field into the cable for aligning the further nanoparticles transversely to the cable length direction.

7. Cable according to claim 6,

d a d u r c h e c e n c i n e s that

the alignment structure comprises an electrically conductive or magnetizable center conductor (210) which extends along the cable length direction and is located in the center of the cable.

8. Cable according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the at least one conductor has a hull layer (70) which is smoother on the outer side (80) facing away from the conductor than on the inner side (90) facing the conductor.

9. Cable according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the at least one conductor has a Hullschicht of a semiconductor material.

10. Cable according to one of the preceding claims,

characterized in that the concentration of the nanoparticles aligned in cable length direction in the electrically conductive conductor is different along the cable length direction, and

along the cable length direction, at least two different concentration ranges are available with nanoparticles aligned in the cable length direction.

11. Cable according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the cable has a circular cross-sectional area and the conductor or conductors are arranged rotationally symmetrically and / or centrally within the circular cross-sectional area.

12. A method for producing a cable (10), in which at least one electrically conductive conductor (20, 110, 110, 120) is embedded in an insulating material (30),

d a d u r c h e c e n c i n e s that

in the electrically conductive conductor nanoparticles (40, 50) are aligned in cable length direction and

- More nanoparticles (60) are aligned transversely to the cable length direction.

13. The method according to claim 12,

d a d u r c h q e c e n c i n c i n h * - I

the other nanoparticles are aligned transversely to the cable length direction by applying a field to the cable.

14. The method according to claim 12 or 13,

d a d u r c h e c e n c i n e s that

- In the cable along the Kabellangsrichtung at least partially an alignment structure is prepared and to the alignment structure, a field is applied, with which the other nanoparticles are aligned transversely to the cable length direction.

15. The method according to any one of the preceding claims 12-14, d a d u r c h e c e n e z e c h e n e, that

the concentration of the nanoparticles aligned in the cable longitudinal direction in the electrically conductive conductor is varied along the cable length direction, and

along the Kabellangsrichtung at least two different sized concentration ranges are prepared with oriented in Kabellangsrichtung nanoparticles.

16. The method according to any one of the preceding claims 12-15, d a d u c h e c e n e c e s e s that

the dielectric constant in the insulation is adapted to the requirements of the electric field by the choice of the concentration and orientation of the nanoparticles in the insulation and / or the conductivity in the conductor by the choice of the concentration and orientation of the nanoparticles in the conductor to the requirements of the electric Conductivity is adjusted, whereby the adjustment of the concentration of sodium particles can take place both in layers and continuously.