EP2140054A1

EP2140054A1 - Composite conducting material

Info

Publication number: EP2140054A1
Application number: EP08707780A
Authority: EP
Inventors: Torbjörn ENG; Kjell Eng
Original assignee: Eng-Tex AB; Eng Tex AB
Current assignee: Eng-Tex AB; Eng Tex AB
Priority date: 2007-03-28
Filing date: 2008-02-19
Publication date: 2010-01-06
Also published as: WO2008116537A1

Abstract

The invention concerns a composite conducting material for transferring energy and a method of producing such a material. The composite conducting material comprises a fabric (10) constituting a base material for the composite conducting material and at least one electrically conducting element (20) associated with the fabric. The fabric (10) is characterized in that it has a structure that is expandable and that the at least one electrically conducting element (20) is associated with the fabric in such a way that the composite conducting material is expandable.

Description

COMPOSITE CONDUCTING MATERIAL

Technical Field

The present disclosure relates to a composite conducting material, and especially to a composite conducting material comprising a fabric constituting a base material for the composite conducting material and a number of electrically conducting elements associated with the fabric.

The composite conducting material is used for transferring energy to or from a medium in which or at which the composite conducting material is placed. In one such field of application, the composite conducting material may be placed in the ground to function as an electrode for watering or dewatering the ground by an electro-osmosis procedure.

Background

WO2006/048594 shows a composite conducting material for use in electro-osmosis, in which a non-conductive polymeric base material is associated with at least one electrode element comprising a metallic element coated with a coating of mixed metal oxides. Thereby, the composite conducting material will have a high corrosion resistance. In WO2006/048594, a textile material that is woven or knitted is used, in which electrode elements are knitted or woven into the textile material.

When manufacturing a piece of a composite conducting material for transferring energy according to prior art, such as the material described in WO2006/048594, the size of the piece has to be adapted to the size of an area where the piece of material is to be used. As a result, a different size of a piece of material has to be produced for each different application. This results in rather high manufacturing costs for each piece of material that is produced. Consequently, there is a need for a composite conducting material that would be more cost-efficient in terms of producing pieces of the material to be used in different applications. Summary

An object of the invention is to create a composite conducting material for transferring energy to or from a medium, which material would be cost- efficient in terms of producing pieces of the material to be used for different applications.

According to a first aspect of the invention, this is achieved by a composite conducting material according to the preamble of claim 1 , which is characterized in that the fabric has a structure that is expandable and that the at least one electrically conducting element is associated with the fabric in such a way that the composite conducting material is expandable.

"A fabric" is defined as any kind of fabric produced from any kind of material used in the textile industry, such as plastic, organic material or any kind of plant fibers.

The fabric may be knitted for receiving its expandable structure. By the material being expandable is meant that the material can be stretched out in a direction of an extension plane of the material. Thereby the same piece of material can cover differently large areas.

The conducting elements are arranged in the fabric in such a way that the material maintains the expandability of the fabric. Also, when the material has been expanded from an original compressed state, the conducting elements may aid in maintaining the expanded state of the material. By the composite conducting material being expandable, the composite conductive material can be manufactured in pieces of a limited number of different standard sizes, and the size of each piece can be adapted to an area or application where it is to be used, after the piece of composite conductive material has been manufactured. By being able to manufacture pieces in a limited number of standard sizes for any possible application, a more cost-efficient manufacturing process could be achieved, since the manufacturing process does not have be specially adapted for each piece of the material that is to be manufactured. Another advantage of the invention is that the material is drape able, i.e. that the material, when placed on an irregular surface, will follow the surface. According to an embodiment of the invention, the expandable structure of the fabric is a net structure. A net is defined as any set of polygons joined edge to edge. The fabric is arranged in such a way that it forms such a net structure. By stretching the net structure in the plane of the fabric, the fabric can be expanded in the plane of the fabric.

According to another embodiment of the invention, the fabric is knitted and the at least one electrically conducting element is associated to the fabric by being knitted into the fabric. By knitting the fabric and the conducting element, a strong and cost-efficient expandable structure can be received for the composite conducting material.

According to yet another embodiment of the invention, the at least one electrically conducting element is arranged to be knitted into the fabric when the fabric is manufactured for receiving its expandable structure. Thereby, the composite conducting material can be manufactured simultaneously as the fabric is manufactured, resulting in a quick and cost-efficient manufacturing process.

The expandable structure of the fabric can be received by arranging the fabric such that it comprises a number of pillar stitches arranged side by side, wherein each pillar stitch in its extension direction has groups of consecutive free stitches alternated with groups of consecutive connection stitches, the connection stitches being connected to one of the pillar stitch's neighboring pillar stitches. In this way a net structure is achieved. When the fabric is expanded in a requested direction, the free stitches will be more aligned in that direction. This can be achieved by quite simply pulling the fabric in the direction in which an extension is required. The more free stitches the fabric has in relation to the number of connection stitches attached to a neighboring pillar stitch, the more expandable is the fabric. According to another embodiment of the invention, the at least one electrically conducting element is associated with the fabric such that the at least one electrically conducting element has an extension direction substantially parallel with the extension direction of the pillar stitches of the fabric. Thereby, a greater expandability is achieved for the composite conducting material. This is based on the fact that when manufacturing the composite conducting material, the pillar stitches are preferably arranged close to each other (see figure 6 showing an unexpanded state of the material). The expandability is therefore greatest in the direction perpendicular to the extension direction of the pillar stitches. If the electrically conducting elements would be arranged perpendicular to the extension direction of the pillar stitches, they would need to extend further than there are pillar stitches in the transversal direction, when the composite conducting material is manufactured. Otherwise, there is a risk that there will be material without electrically conducting elements when the material has been expanded, since the length of the conducting elements would be too short. Also, the electrically conducting elements should preferably be associated with the fabric in such a way that they can slide on the fabric, for easily expanding the composite conducting material. A low sliding friction is achieved between the electrically conducting elements and the fabric if the electrically conducting elements are arranged in the extension direction of the pillar stitches.

According to an embodiment of the invention, the at least one conducting element comprises a number of conductors associated with the fabric such that the number of conductors have a substantially parallel extension direction. Thereby, the composite conductive material can be expanded in at least a direction transversal to the extension direction of the conductors, without the conductors limiting the expansion possibilities. This also implies that the distance between each conductor will increase when the composite conducting material is expanded. As a result, the amount of energy transmitted per area can be decreased without changing the current flowing through each conductor. This fact can be used for accomplishing pieces of the material with different energy density from the same manufactured piece of material. As a result, flexibility is achieved such that a lower amount of different standard pieces has to be manufactured for different applications. In an equivalent way, the amount of energy can be increased by compressing the material.

According to another embodiment, the at least one conducting element comprises a number of conductors, each of the number of conductors being integrally arranged with a pillar stitch. Thereby, each of the conductors will be protected by the fabric. In addition, the conductors will follow the movement of the material when the material is expanded. As a result, a flexible and durable material is received, which has a low risk for breakage of the conductors. If large amounts of energy are to be transferred, the conductors have to be large to be able to cope with high current levels. In that case the conductors are not flexible enough to be able to be integrated in a pillar stitch and still give the composite conductive material enough flexibility and expandability. To avoid this problem, each of the number of conductors can be arranged in the material such that they have a substantially straight extension, and such that each of the number of conductors is associated with the fabric at places where a pillar stitch is connected to a neighboring pillar stitch.

According to still another embodiment, neighboring conductors are associated with the fabric such that they come into contact with each other at selected places in the material. Thereby, a rather good distribution of energy is ensured in the composite conducting material even if a breakage would occur in any of the conductors of the material. In an alternative of this embodiment, the selected places are evenly spread in the material, ensuring an even distribution of energy at a breakage of a conductor. In an advantageous embodiment for ensuring an even distribution of energy at a conductor breakage, the selected places are the places where neighboring pillar stitches are connected to each other.

According to another alternative of this embodiment, neighboring conductors come into contact with each other by crossing each other at least two times at each selected place in the material. Thereby, connection between each neighboring conductor is ensured, whereby an even distribution of energy is ensured to an even higher degree.

According to another aspect of the invention, there is provided a sheet of a composite conducting material according to the first aspect of the invention, which sheet comprises a first part wherein the at least one conducting elements are associated with the fabric and a second part wherein the at least one conducting elements are separated from the fabric. Thereby, the second part could be used to create connection points for connecting a current source to the conducting elements. Such a sheet can also be cost- efficiently manufactured since a sheet can be manufactured in one process comprising a number of first and second parts occurring at repeated intervals in the material.

According to a third aspect of the invention, a method is provided for manufacturing a composite conducting material comprising a fabric constituting a base material for the composite conducting material and at least one electrically conducting element associated with the fabric. The method comprises the steps of manufacturing the fabric in such a way that it obtains an expandable structure, and associating the at least one electrically conducting element to the fabric such that the composite conducting material is expandable. Thereby, the composite conducting material can be manufactured in pieces of a limited number of different standard sizes, and the size of each piece can be adapted to an area or application where it is to be used, after the piece of composite conductive material has been manufactured.

According to an embodiment of the third aspect of the invention, the steps of manufacturing and associating are performed simultaneously. Thereby, the composite conducting material can be manufactured simultaneously as the fabric is manufactured, resulting in a quick and cost- efficient manufacturing process.

According to another embodiment of the third aspect of the invention, the method further comprises the steps of arranging a number of threads, such as warp threads, of the fabric side by side and arranging a number of electrically conducting elements side by side, mixed with the threads, before the steps of manufacturing and associating are performed. Thereby, a stitched composite conducting material can be manufactured by the same manufacturing machine as used for manufacturing the fabric, which may be a machine that can be used for ordinary fabric stitching.

The composite conducting material according to the invention may be used for any type of application regarding transfer of energy through a medium, such as an electro-osmosis procedure. Another type of possible applications for the composite conducting material is as a net for marine applications for protecting fish cultures from predators. Yet another type of possible application is as an electrode in a capacitor for storing energy in a medium such as in the ground. Still another type of possible application is as an electrode in a photovoltaic cell.

Brief Description of the Drawings

The invention will in the following be described in more detail with reference to the enclosed drawings. Figure 1 illustrates a schematic view of an expandable knitted structure of a fabric used as base material in a composite conducting material according to the invention.

Figure 2 illustrates a schematic view of an embodiment of a composite conducting material according to the invention. Figure 3 shows a threading diagram of an embodiment of a composite conducting material according to the invention.

Figure 4 illustrates a schematic view of another embodiment of a composite conducting material according to the invention.

Figure 5 shows a front view of an expanded state of a composite conducting material in shape of a net.

Figure 6 shows a front view of an unexpanded state of the composite conducting material of fig 5.

Figure 7 shows a front view of a composite conducting material where for a part of the material, the electrical conductors are separated from the fabric.

Figure 8 shows a flow chart of a method of the invention.

Description of Embodiments

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, like numbers refer to like elements.

Figure 1 shows an embodiment of a fabric 10 that can be used in a composite conducting material according to the invention. The fabric 10 is warp-knitted and comprises a number of pillar stitches 11a-11d arranged side by side. The pillar stitches are stitched from a number of warp threads. Each pillar stitch is stitched into its neighboring pillar stitches such that a fabric in shape of a net structure is created. Each pillar stitch 11a-11d is stitched into its neighboring pillar stitches in such a way that in an extension direction of each pillar stitch, each pillar stitch comprises a number of free stitches 12 and a number of connection stitches 13 directly connected to a neighboring pillar stitch. In the fabric of figure 1 , a pillar stitch 11c has in its extension direction, one free stitch 12 followed by two connection stitches connected to a first neighboring pillar stitch 11d, followed by one free stitch and two connection stitches connected to a second neighboring pillar stitch 11 b. The first neighboring pillar stitch 11d would be e.g. the pillar stitch closest to the right of the pillar stitch 11c and the second neighboring pillar stitch 11 b would e.g. be the pillar stitch closest to the left of the original pillar stitch 11c, or vice versa. By for each pillar stitch 11a-d alternately connecting groups of two connection stitches 13 to each pillar stitch's first and second neighboring pillar stitches and separating alternately connected groups of connection stitches by at least one free stitch 12, the thus created fabric will receive a net structure that can be expanded in a direction. If the fabric is expanded in e.g. a direction transversal to an extension direction of the pillar stitches, the free stitches will be directed more into the transversal direction whereby the fabric will be expanded in that direction. At the same time, the fabric will be compressed in the extension direction.

The expression pillar stitch is used for describing a row of stitches in a stitched fabric. The expression pillar stitch would be similar to the expression row of wales.

Figure 2 shows an embodiment of a composite conducting material according to the invention. The material comprises a fabric 10 stitched such that it has an expandable net structure. The fabric 10 is stitched in a different way than the fabric shown in figure 1. The fabric 10 comprises a number of pillar stitches 11a-11d arranged side by side. Each pillar stitch is stitched into its neighboring pillar stitches such that a fabric in shape of a net structure is created. The fabric 10 comprises a number of free stitches 12 and a number of connection stitches 13, connecting a pillar stitch to one of its neighboring pillar stitches. The material also comprises a number of electrically conducting elements 20 in shape of a number of metal wires. The metal wires 20 are arranged in parallel into the fabric 10 in such a way that it is possible to expand the composite conducting material. In figure 2, the metal wires 20 have been stitched into the fabric 10 such that the structure of the fabric forms a channel that receives and protects the metal wires. The material can be expanded in any direction without the metal wires hindering the expansion. Although, if the material is expanded in a direction transversal to an extension direction of the metal wires, the material will be compressed in the extension direction of the metal wires.

Figure 3 shows a threading diagram of another embodiment of a composite conducting material according to the invention. In this embodiment, electrical conductors 20 are integrated into pillar stitches 11a-r for a fabric 10. The fabric is stitched such that each pillar stitch 11a-r in its extension direction has alternating groups of seven consecutive free stitches 12 and groups of two connection stitches 13 connected to a neighboring pillar stitch, where every second group of connection stitches is connected to a first neighboring pillar stitch and every other second group of connection stitches is connected to a second neighboring pillar stitch. Generally, the more free stitches in relation to the number of connection stitches, the more expandable the fabric. Thereby, the fabric shown in figure 3 is more expandable than the fabrics shown in figures 1 and 2. The stitching method is similar to the stitching method shown in figure 1. In this embodiment, each metal wire 20 is arranged integrally with a pillar stitch 11. If the fabric is expanded, the metal wires will follow the expansion and, consequently, the composite conducting material will be expandable.

Also in figure 3, neighboring metal wires come into contact with each other in an area close to the connection stitches 13. Thereby, a rather even distribution of energy is ensured in the composite conducting material even if a breakage would occur in any of the metal wires of the material. As seen in figure 3, neighboring metal wires come into contact with each other at a connection area close to each group of connection stitches by crossing each other. In the embodiment of figure 3, the metal wires cross each other at each connection stitch, i.e. two times at each connection area. In an alternative embodiment, the metal wires may cross each other more or less than two times at each connection area. If the metal wires cross each other an odd number of times, this implies that the metal wires change pillar stitch at each connection area.

Figure 4 shows an alternative embodiment for associating the electrically conducting elements 20 with the fabric 10. Here, each conducting element 20 is not integrated with a pillar stitch (11a-l), but instead the conducting elements are arranged in parallel and connected to the fabric at frequently occurring selected places. Preferably the conducting elements are arranged to the fabric at the connection stitches 13 of neighboring pillar stitches. Thereby, the arrangement of the conducting elements 20 will enable the composite conducting material from being expandable, at least in any direction that is not parallel to the direction of the conducting elements. This alternative embodiment is preferably used when thicker metal wires are used, which is the case if the metal wires shall be capable of transferring higher amounts of energy. Such thicker metal wires are not flexible enough to be able to integrate into the fabric and give the material a requested flexibility. Although the same stitching method is used in figure 4 as in figure 1 , it should be understood that for realizing the alternative embodiment described above for associating the electrically conducting elements with the fabric, any possible manufacturing method that makes the fabric expandable could have been used.

As is evident from each of the figures 2-4, the electrically conducting elements 20 are arranged to the fabric 10 such that the electrically conducting elements have an extension direction that is substantially parallel with the extension direction of the threads of the fabric, i.e. the pillar stitches of the fabric. Figures 5 and 6 illustrate the expandability of a composite conducting material according to the invention that has a net structure. The composite conducting material comprises a fabric that has been stitched into a net structure and a number of conductors stitched into the fabric in such a way that the conductors are integrally arranged in the fabric. Figure 6 shows the material in an unexpanded state and figure 5 shows the material when it has been expanded in a horizontal direction in the figure.

Figure 7 shows another embodiment of the invention. In this embodiment, a sheet of composite conducting material according to the invention can be produced that has a first part 40 consisting of the composite conducting material, i.e. comprising an expandable fabric with associated electrically conducting elements, and a second part 50 where the electrically conducting elements are not associated with the expandable fabric. The second part is intended to be used for easily creating connections for connecting a current source to the composite conducting material. Such a sheet can be cost-efficiently manufactured since a sheet can be manufactured in one process comprising a number of first and second parts occurring at repeated intervals in the material. The flat plate 60 in figure 7 is not a part of the invention. It is only shown for illustrative purposes, to better illustrate that in the second part, the electrically conducting elements are actually separated from the fabric.

Figure 8 shows an embodiment of a method for producing a piece of a composite conducting material according to the invention. The method comprises the steps of: Arranging 101 a number of threads of a material used in the textile industry side by side;

Arranging 102 a number of electrically conducting elements side by side mixed with the threads;

Manufacturing 103 the fabric 10 from the number of threads in such a way that the fabric obtains an expandable structure; and

Associating 104 the at least one electrically conducting elements 20 to the fabric such that the composite conducting material is expandable. The threads may be warp threads. In the step of manufacturing the fabric, the threads are stitched into pillar stitches.

By performing the steps of manufacturing 103 and associating 104 simultaneously, a quick and cost-efficient production process for producing a composite conducting material according to the invention is achieved.

The steps of manufacturing 103 and associating 104 may be performed in any relative order or simultaneously.

The step of manufacturing may be performed by stitching the threads into pillar stitches that are connected to neighboring pillar stitches such that each pillar stitch has a number of free stitches and a number of connection stitches, wherein the connection stitches are directly connected to a neighboring pillar stitch. The connection stitches may be arranged in groups comprising consecutive connection stitches. Similarly, the free stitches may be arranged in groups of consecutive stitches. The stitching may be performed such that each pillar stitch has alternating groups of consecutive free stitches and consecutive connection stitches, where every second group of connection stitches of a pillar stitch is connected to a first neighboring pillar stitch and every other second group of connection stitches of the pillar stitch is connected to a second neighboring pillar stitch. Each of the at least one electrically conducting element may be associated with the fabric such that the at least one electrically conducting elements is integrated in a pillar stitch of the fabric.

The fabric 10 may be knitted in any way that makes it expandable; for this reason it may be e.g. warp-knitted or weft-knitted into a net structure. In an alternative embodiment, the fabric may be a knotted net. In this case the fabric comprises threads that are tied together at each connection area. The fabric may have any kind of expandable structure, such as a net structure or a mesh structure. The composite conducting material is preferably an elongate sheet material. The electrically conducting elements 20 could be associated with the material in any way that will not prevent the composite conducting material from being expandable.

Fields of application of the composite conductive material

The composite conducting material according to the invention may be used for any type of application regarding transfer of energy through a medium, such as in an electro-osmosis procedure. The material may be used for electro-osmosis to speed up a composting process in e.g. a basin or a stack of sludge. In that case an electrode in shape of e.g. a number of pipes may be arranged in the bottom of the basin or the stack and an electrode made of a piece of the composite conducting material according to the invention will be arranged in or at the top of the sludge. A voltage will be applied over the electrodes, whereby the pipes will function as an anode and the composite conducting material will function as a cathode, such that water in the sludge will be transferred to the pipes and transported away from the sludge via the pipes. The composite conducting material might be used in similar ways for other applications where an electro-osmosis procedure would be beneficial, e.g. for de-watering grounds, such as a football field, or for watering grounds, such as a field for growing vegetables.

Another type of possible application for the composite conducting material is as a net for marine applications, e.g. for protecting fish cultures from predators. In that case the composite conducting material will function as an electrode arranged on the outside of a fish culture. AC- or DC-current will be applied to the material and surrounding water will function as a corresponding electrode. An approaching predator fish would be unpleasantly affected by the electricity, or even get an electrical shock when at a close distance to the net, and will therefore be scared off from the fish culture. Also, the composite conducting material would prevent building up of algae on surrounding wall of a fish culture. For this reason, the composite conducting material according to the invention might also find use around hulls of boats. Yet another type of possible application of the composite conducting material according to the invention is as an electrode in a capacitor for storing energy in a medium such as in the ground.

Still another type of possible application of the composite conducting material according to the invention is as an electrode in a photovoltaic cell or as a part of a photovoltaic cell.

In WO2006/048594 the electrode elements of a composite conducting material are coated with a metal oxide to decrease oxidation at the surface of the electrode elements. According to another embodiment of the invention, a type of electrically conducting impregnation means is used to impregnate the composite conducting material when it is manufactured or after it has been manufactured. The electrically conducting impregnation means may either be applied to the electrical conductors before the material is manufactured, or to the composite conducting material comprising the conductors after the material has been manufactured. In the latter case, both the fabric and the electrical conductors are coated (impregnated) with the impregnation means. Such an impregnation means would be arranged to prevent oxidation at the surface of the electrical conductors. The impregnation means is cost-efficient as such. Also, the resulting impregnated composite conducting material would have a high resistance to corrosion. In addition, the impregnated composite conducting material would be more cost-efficient to produce than the composite conducting material shown in WO2006/048594. The impregnation means may be a flexible thermoplastic solution or dispersion comprising carbon suspended in the solution or dispersion. In the drawings and specification, there have been disclosed preferred embodiments and examples of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation, the scope of the invention being set forth in the following claims.

Claims

1. A composite conducting material for transferring energy, comprising: a fabric (10) constituting a base material for the composite conducting material; at least one electrically conducting element (20) associated with the fabric; characterized in that the fabric (10) has a structure that is expandable and that the at least one electrically conducting element (20) is associated with the fabric in such a way that the composite conducting material is expandable.

2. A composite conducting material according to claim 1 , wherein the expandable structure of the fabric (10) is a net structure.

3. A composite conducting material according to claim 1 or 2, wherein the fabric (10) is knitted for receiving its expandable structure and the at least one electrically conducting element (20) is associated with the fabric (10) by being knitted into the fabric.

4. A composite conducting material according to claim 3, wherein the at least one electrically conducting element (20) is arranged to be knitted into the fabric (10) when the fabric is manufactured for receiving its expandable structure.

5. A composite conducting material according to any of claims 1-4, wherein the fabric (10) comprises a number of pillar stitches (11a-r) arranged side by side, wherein each pillar stitch is connected to its neighboring pillar stitch or stitches.

6. A composite conducting material according to claim 5, wherein the expandable structure is achieved by each pillar stitch (11a-r) in its extension direction having groups of consecutive free stitches (12) alternated with groups of consecutive connection stitches (13), the connection stitches being connected to either of the pillar stitch's neighboring pillar stitches.

7. A composite conducting material according to claim 6, wherein a group of consecutive free stitches (12) comprises more stitches than a group of consecutive connection stitches (13).

8. A composite conducting material according to any of claims 5-7, wherein the at least one electrically conducting element (20) is associated with the fabric (10) such that the at least one electrically conducting element (20) has an extension direction substantially parallel with the extension direction of the pillar stitches (11 a-r) of the fabric (10).

9. A composite conducting material according to any of claims 1-8, wherein the at least one conducting element (20) comprises a number of conductors associated with the fabric such that the number of conductors have a substantially parallel extension direction.

10. A composite conducting material according to any of claims 6-9, wherein the at least one conducting element (20) comprises a number of conductors, and wherein each of the number of conductors is integrally arranged with a pillar stitch (11a-r).

11. A composite conducting material according to claim 9 or 10, wherein each of the number of conductors (20) is associated with the material such that they have a substantially straight extension, and wherein each of the number of conductors is associated with the fabric (10) at places where a pillar stitch (11 ) is connected to a neighboring pillar stitch.

12. A composite conducting material according to any of claims 1-

11 , wherein the at least one conducting element (20) comprises a number of conductors arranged side by side associated with the fabric (10), wherein neighboring conductors are associated with the fabric such that they come into contact with each other at selected places in the material.

13. A composite conducting material according to claim 12, wherein at each selected place, neighboring conductors (20) come into contact with each other by crossing each other at least one time.

14. A composite conducting material according to any of claims 1- 13, wherein at least the electrically conducting elements (20) are impregnated with an electrically conducting impregnation means.

15. A sheet of a composite conducting material according to any of the preceding claims, wherein the sheet comprises a first part (40) in which the at least one conducting elements (20) is associated with the fabric (10), and a second part (50) in which the at least one conducting element is separated from the fabric.

16. Method for manufacturing a composite conducting material, comprising a fabric (10) constituting a base material for the composite conducting material and at least one electrically conducting element (20) associated with the fabric; the method being characterized in that it comprises the steps of:

Manufacturing (103) the fabric (10) in such a way that it obtains an expandable structure,

Associating (104) the at least one electrically conducting element (20) with the fabric (10) such that the composite conducting material is expandable.

17. Method according to claim 16, wherein the steps of manufacturing (103) and associating (104) are performed simultaneously.

18. Method according to any of claim 16 or 17, the method further comprising the steps of, before the manufacturing step (103):

Arranging (101 ) a number of threads (11a-r) for forming pillar stitches of the fabric (10) side by side;

Arranging (102) a number of electrically conducting elements (20) side by side, mixed with the threads (11a-r).