Improved conductor

Abstract

Conductor (100) with longitudinal development for a flexible electric charging cable (200), said conductor is characterised in that it comprises at least six strands (110) braided in such a way as to define a self-supporting tubular structure, which is free of internal elements, with a central channel (120) wherein a cooling fluid (12) flows in use which laps said strands (110), each of said strands (110) being made with at least four wires (111) of an electrically conductive material wound together in a helical manner, at least one of said six strands (110) being braided in the opposite direction to the other strands (110).

Description

[0001] IMPROVED CONDUCTOR

[0002] TECHNICAL FIELD

[0003] The present invention relates to the field of technologies for the electrical charging of electric devices and cars.

[0004] The present invention can be advantageously employed in the technical sector of the production and marketing of devices and accessories for the charging and maintenance of electric and / or hybrid vehicles, in particular in the technical sector of the production and marketing of electric cables intended to be electrically connected on one side to a source of electric energy (e.g. a charging tower) and on the other to the electric vehicle for the charging of electric batteries mounted on the latter.

[0005] STATE OF THE ART

[0006] One of the main factors that limit the spread of electric vehicles is the charging time, for this reason, in recent times increasingly rapid charging technical solutions are being developed. The charging speed depends on the system installed, in particular on the power that it is able to deliver over time.

[0007] To date, in alternating current (AC) it is possible to have solutions that range from a power of 2.3 kW to a maximum of 43 kW, values that imply the need for hours for a complete recharge, therefore compatible with a home recharge during the night or during the daily stop during working hours.

[0008] For this reason, solutions are being developed that exploit direct current (DC) with higher voltages and currents than the previous ones, to allow to reach for greater power outputs and obtain, consequently, shorter charging times. These are defined as “Mode 4” charging according to I EC 618511 and involve the use of higher voltages (up to 1.5kV DC) and higher currents.

[0009] The applicable regulations, drawn up by the “International Electrotechnical Commission”, provide for a maximum temperature on the conductor of 90°C (I EC 62893 Series) and can even provide for conductors with a nominal section of up to 150mm2. These charging cables allow for power outputs of up to 200kW, while, to meet the need for truly extremely rapid charging, it is hoped to be able to reach powers of 500kW and beyond.

[0010] The problem is that such powers are obtained by increasing the current, which produces a heating of the conductor due to the Joule effect, representing a limiting factor in the possibility of reaching such values.

[0011] The solution to this problem, since the power dissipated in the form of heat depends on the passing current and the electrical resistance of the conductor, is to increase the crosssection of the copper conductor used in the electrical cable connecting the charging station to the electric vehicle (to reduce its electrical resistance, since P = l2R, where “P” is the Power dissipated due to the Joule effect, “I” is the Current Intensity and “R” is the Resistance of the conductor). This, in the case of wanting to supply a power of 500kW at 1 kV DC, is equivalent to a conductor with a cross-section of 240mm2. This is not compatible with a charging cable for an electric vehicle, due to issues relating to the weight, size and handling of what would be the resulting cable (as a reference, “mode 3” charging cables have conductors that do not exceed a copper cross-section of 25mm2).

[0012] For these reasons it is necessary to develop a solution that allows the delivery of such power, and higher, with copper sections reduced by almost ten times that reported above and therefore, by way of example but not limitation, included in the range between 25mm2and 50mm2.

[0013] The principle of the invented solution involves removing the heat generated on the conductor, resulting from the passage of current, through direct contact of the conductor itself with a refrigerant liquid, such as, by way of example but not limitation, a silicone oil having suitable viscosity and dielectric characteristics.

[0014] The present invention relates to the way for constructing the insulated conductor which allows it to be cooled by direct contact with the flow of fluid passing through it.

[0015] The problem illustrated above does not concern only the cable, but also the connector which provides for the relative contacts directly lapped by the coolant, this solution, regarding the connector, provides for having two separate chambers for each pole or alternatively even the same contact chamber, the coolant being an insulating dielectric.

[0016] Over the years, many patents have been developed to provide technical solutions to remove the heat generated by the Joule effect from a conductor.

[0017] An example is document WO2022226730A1 which describes an electric cable for charging electric vehicles where the DC power transmission is achieved through several separate and insulated conductors surrounding two tubes, one for delivery and the other for return, inside which a cooling liquid circulates.

[0018] Similarly, document CN106782835A describes a cooled cable where the cooling liquid passes through a central tube, above which the conductor is built, i.e. the conductive metal part is in contact with the outside of the tube containing the cooling liquid.

[0019] Similarly, in document US6100467A there is a central tube, through which the cooling liquid passes, above which several conductive elements are strung to form the cooled conductor.

[0020] In document CN114464363A there is instead an external jacket to the conductor, which separates it from the cooling liquid. ln document CN216623868U there are channels that instead of being in contact with the conductor are placed above the insulation of the conductor itself; therefore, on the outside while in the previous solutions it was on the inside, in this case the cooling liquid is in contact with the layer of insulation material of the conductor.

[0021] In CN112289497A, in addition to increasing the resistance of the insulating material covering the conductor, cooling occurs through a conduit inside which the conductors are inserted including their insulating layers (electrical, but which are also thermally insulating, reducing the effectiveness of the heat exchange).

[0022] The main drawback of the solutions just mentioned is that since there is no direct contact between the cooling medium and the conductive metal part, the cooling efficiency and the capacity to increase the passing current in the same copper section are significantly limited. This happens because the material that separates the cooling liquid from the conductor has a certain degree of thermal insulation, making the heat exchange inefficient.

[0023] These solutions are believed to be improvable through cooling by direct contact between the conductor (metallic part carrying current) and the cooling liquid (without the interposition of a barrier, which also acts as a thermal barrier to heat exchange).

[0024] The solutions reported in documents WO2022217432A1 and EP3882929A1 provide for direct contact between metal and cooling liquid, as there is a channel wherein the cooling liquid flows and touches the circuits.

[0025] The main drawback of the solutions just reported is that the channel wherein the cooling liquid flows is supported by structural support elements inside the conductor, which however limit its flexibility making the cable less easy to handle (in the first case it is a conductor that becomes rigid and therefore totally unsuitable for the purpose of an electric vehicle charging cable).

[0026] A further drawback, which the presence of the structural support elements in the flow channel brings along, is related to the fact that the cable thus constructed has a limited ratio between the volume of the conductor and the cooled section (section of direct contact between the cooling liquid and the conductor). The presence of internal structural elements, which are in contact with the elements that conduct current and are to be cooled, effectively reduces the surface (of the conductors) free to be lapped by a cooling fluid as well as reduces the free section for the passage of the fluid (being partly occupied by the presence of the structural elements), thus affecting its efficiency.

[0027] Similarly in documents CN113851269A and DE202015009531 U1 the conductor is immersed in the liquid inside the insulation tube.

[0028] The main drawback of the solutions described in the documents just cited is linked to the fact that even though in these solutions there is direct contact between the liquid and the conductor, it is not possible to ensure a regularity of the extruded insulation layer, nor of the distance between the conductor and the insulating coating, since the former fluctuates in the latter.

[0029] A further drawback is linked to the absence of any element that prevents the collapse (due to bending or flattening) of the external layer of insulation on the conductor, thus obstructing (partially or completely) the flow of the cooling liquid and affecting the cooling mechanism, making it ineffective.

[0030] In the proposed solution according to the present invention, the insulation layer is extruded by depositing it above the conductor, being the central channel wherein the refrigerant fluid flows inside the conductor itself, thus allowing dimensional control as in a common extrusion of insulation above the conductor. In the configuration of the present invention, the particular construction of the conductor provides a structural support that prevents bending and flattening of the cable and which is such as not to interfere (by reducing or completely occluding the flow section) with the flow of the refrigerant liquid, without compromising its flexibility for the application in charging electric vehicles.

[0031] Other known solutions are described in ON212322712, US2022 / 037056 and FR2430069.

[0032] Unless specifically excluded in the detailed description that follows, the description in this chapter is to be considered as an integral part of the detailed description of the invention. OBJECTS OF THE INVENTION

[0033] The object of the present invention is to propose a cable for electric charging, and in particular for charging an electric vehicle, which allows to overcome, at least in part, the drawbacks of the known solutions.

[0034] The object of the present invention is to propose a conductor for an electric charging cable that allows to overcome, at least in part, the drawbacks of the known solutions.

[0035] Another object of the invention is to propose a charging cable that allows direct contact between one or more conductive elements that overheat and a cooling fluid.

[0036] Another object of the invention is to propose a charging cable that has a flexibility, weight and size that allows its use in an electric vehicle charging station.

[0037] Another object of the invention is to propose a charging cable wherein the distance between the conductive part and the insulating part remains fixed.

[0038] Another object of the invention is to propose a charging cable that does not require specific structural supports to maintain a constant cross-section of an internal central channel wherein a cooling fluid flows.

[0039] Another object of the invention is to propose an electric charging cable that can be produced simply, quickly and at low cost. Another object of the invention is to propose an electric charging cable of smaller dimensions (particularly in terms of external diameter) than known solutions.

[0040] Another object of the invention is to propose an electric charging cable with reduced weight compared to known solutions.

[0041] Another object of the invention is to propose a conductor for an electric charging cable that can be produced simply, quickly and at low cost.

[0042] Another object of the invention is to propose a conductor for an electric charging cable that can be substantially produced with machines already known to the state of the art.

[0043] Another object of the invention is to propose an electric charging conductor and / or cable that is an improvement and / or alternative to traditional solutions.

[0044] Another object of the invention is to propose an electric charging conductor and / or cable with an alternative characterization, both in functional and implementational terms, compared to traditional solutions.

[0045] Another object of the invention is to propose an electric charging conductor and / or cable that can be mass-produced quickly and efficiently. Another object of the invention is to propose an electric charging conductor and / or cable that can be manufactured on an industrial scale effectively and without any limitation in terms of length.

[0046] Another object of the invention is to propose a conductor for an electric charging cable that is both coolable and highly flexible.

[0047] Another object of the invention is to propose an electric charging conductor and / or cable capable of offering the widest guarantees of reliability and safety.

[0048] SUMMARY OF THE INVENTION

[0049] All these objects, whether individually or in any combination thereof, and others which will result from the following description are achieved, according to the invention, with a conductor with the characteristics indicated in claim 1 , with a cable with the characteristics of claim 21 and / or with a system with the characteristics indicated in claim 25. DESCRIPTION OF THE FIGURES

[0050] The present invention is further clarified below in some of its preferred practical embodiments reported for purely exemplary and non-limiting purposes with reference to the attached drawings, wherein:

[0051] Figure 1 shows the section of a strand 110 formed by elements (wires 111) of conductive material wound in a helical manner;

[0052] Figure 2 shows a perspective view of a strand 110 formed by elements (wires 111) of conductive material wound in a helical manner; Figure 3 shows a section of a conductor 100 with eighteen strands 110 twisted together;

[0053] Figure 4 shows a side view of a conductor 100 with eighteen strands 110 twisted together;

[0054] Figure 5 shows a sectional view of a conductor 100 according to the present invention;

[0055] Figure 6 shows a side view of a conductor 100 according to the present invention;

[0056] Figure 7 shows a schematic cross-sectional view of a cross-winding process of some strands 110 of a conductor 100 according to the present invention;

[0057] Figure 8 shows a schematic perspective view of the braiding process of some strands 110 of a conductor 100 according to the present invention;

[0058] Figure 9 shows a diagram of a path of a cooling fluid 12 exchanging heat with a conductor 100 in a system 500 according to the present invention, consisting of an electrical source 510, a cooling unit 520;

[0059] Figure 10 shows a sectional view of a connector 400 for a conductor 100 according to the present invention;

[0060] Figure 11 shows a perspective view of a connector 400 for a conductor 100 according to the present invention;

[0061] Figure 12 shows a front view of an electric vehicle charging plug 600 using the cable 200 according to the present invention;

[0062] Figure 13 shows a sectional view of an electric vehicle charging plug 600 containing the cable 200 according to the present invention;

[0063] Figure 14 shows a sectional view of a flexible charging cable 200 with two conductors 100, one acting as a delivery and the other as a return of the cooling fluid 12 from and towards a cooling unit 520, sheathed with material 210, according to the present invention;

[0064] Figure 15 shows a sectional view of a flexible charging cable 200 with two conductors 100 and two tubular elements 220, which act as a return (or delivery) of the cooling fluid 12 towards and from a cooling unit 520, according to the present invention;

[0065] Figure 16 shows a sectional view of a flexible charging cable 200 with two conductors 100 and a tubular element 220 according to the present invention;

[0066] Figure 17 shows a sectional view of a flexible charging cable 200 with two conductors 100, two tubular elements 220 and a grounding cable 230 according to the present invention; Figure 18 shows a sectional view of a flexible charging cable 200 with two conductors 100, two tubular elements 220, a ground wire 230, one or more pilot conductors 240 and two casings 210 according to the present invention;

[0067] Figure 19 shows a diagram representing the trend of the dissipated thermal power and of the measured temperature over time during a test on a prototype of conductor 100 according to the present invention.

[0068] DEFINITIONS

[0069] In the scope of the present invention, reference is made to quantities and elements for which a definition is provided below within the scope of the invention:

[0070] - Longitudinal axis of a cable: axis that runs along the length of a cable and passes through the centers of all sections generated by a plane of any orientation that divides the cable into two parts;

[0071] - Winding direction: the direction of a strand / wire being wound and which can be clockwise (also called right-handed) or counterclockwise (also called left-handed);

[0072] - Winding / braiding pitch: distance along the longitudinal axis of a cable / conductor, which a single wound strand / conductor / wire travels to describe an entire circle in section;

[0073] - Delivery pipe / cable / duct: the pipe / cable / duct through which a cooling fluid flows when exiting a cooling unit;

[0074] - Return pipe / cable / duct: the pipe / cable / duct through which a cooling fluid flows after exchanging heat and being directed to a cooling unit;

[0075] - Grounding conductor: protective conductor that connects the main ground collector (or node) to the ground rod / plate or connects the ground rods / plates together, if required;

[0076] - Pilot conductor cable: small cross-section conductor (preferably between 0.5mm2and 1.5mm2) for the transport of electrical signals, and preferably carrying low amperage currents;

[0077] - Contacts: elements made of electrically conductive material present on a plug or pin of a type of connection called indeed “plug” (composed of a plug / pin and a socket), which allows contact on various types of electrical lines.

[0078] DETAILED DESCRIPTION OF THE INVENTION AND SOME OF ITS PREFERRED EMBODIMENTS

[0079] The object of the present invention is the realization of a coolable cable for charging electrical energy storage systems with cross-winding (or braiding) of multiple strands in electrical contact with each other. Said storage systems being, by way of example but not limited to or binding, electric vehicle batteries.

[0080] Preferably, the electric cable according to the invention can be advantageously used to electrically connect a source of electric energy to an electric car to be recharged. The term "electrical energy" shall be understood hereinafter as a generic term to indicate all the electrical quantities normally necessary and used to recharge an electric battery, in particular power, voltage and electric current. The present invention involves cooling the conductor inside the cable by direct contact with a cooling fluid, through a channel created inside the conductor, thanks to its construction, free of internal elements that limit its flexibility and the contact surface between conductors and cooling fluid.

[0081] Considering a traditional conductor constructed from two or more layers of strands, the best resistance to compression is achieved by alternating the direction of the successive layers (clockwise-counterclockwise, rather than clockwise-clockwise or counterclockwise- counterclockwise). This construction method does not allow for a structure that is sufficiently resistant to compression to allow cavities to be created inside the conductor.

[0082] Advantageously, in the present invention, it is possible to create a cavity inside the conductor, by adopting the solution of placing the different layers of strands, in this case of the strands, in alternating direction on the same plane. In this way, there are no longer two layers of strands in alternating direction but a single layer with strands that cross each other in alternating direction, thus creating a structure resistant to compression. Conveniently, in the present invention, strands of a specific pitch and direction are used by winding them in a crossed manner (preferably braiding) with other strands in alternating direction in a single plane, thus creating a stable and hollow structure inside it.

[0083] Preferably, the external cross-section of the conductor has a shape that is substantially round onto which the insulation is extruded creating a dimensionally defined and stable circular structure.

[0084] The present invention will now be illustrated purely by way of example but not in a limiting or binding manner, with reference to the figures which illustrate some embodiments relating to the present inventive concept.

[0085] The conductor 100 according to the present invention, for a flexible electrical charging cable 200, comprises at least six strands 110 wound / braided together (preferably in a crossed manner) and each made with at least four wires 111 of an electrically conductive material wound together in a helical manner (preferably stranded); at least one of said six strands 110 being braided in the opposite direction between clockwise and anticlockwise with respect to the other strands to form a central channel 120 wherein a cooling fluid 12 flows in use, lapping the strands 110.

[0086] The conductor 100 has longitudinal development.

[0087] The conductor 100 comprises at least six strands 110 which are braided so as to define a self-supporting tubular structure with a central channel 120 wherein a cooling fluid 12 flows in use which laps said strands 110. At least one of said six strands 110 is braided in the opposite direction to the other strands 110.

[0088] In particular, the tubular structure of the conductor 110 is self-supporting and is obtained by braiding the strands 110, each of which is made by helically winding at least four wires. In essence, in the conductor 110, not single wires are braided, but rather strands

[0089] 110 each formed by a helical winding of at least four wires.

[0090] Each of said at least six strands 110 is made with at least four wires 111 of an electrically conductive material wound around each other in a helical manner. All the wires

[0091] 111 of each strand are wound around each other in a helical manner and, in particular, there is no central wire around which the others are wound.

[0092] Conveniently, the self-supporting tubular structure (in terms of physical-mechanical consistency) of the conductor 100 with the central channel 120 is obtained by the braiding method of the strands 110, each of which is made with at least four wires 111 wound together in a helical manner. Advantageously, therefore, during the manufacturing phase of the conductor 100, a dedicated central support body or element for the strands is not used; this allows for the simplification of the production, especially at an industrial level, of the conductor 100. Advantageously, furthermore, in the finished conductor 100 no dedicated central support body or element for the strands is provided.

[0093] FIGS. 1 and 2 show respectively in section and in perspective a strand 110 made by helically winding thirty-seven wires 111.

[0094] Said strand 110 being preferably but not limitedly a conductor of flexibly and helically wound wires 111.

[0095] Conveniently, said wires 111 of each strand 100 are made of an electrically conductive material (for example but not limited to copper).

[0096] Preferably, but not limitedly, said wires 111 have a diameter in the range between 0.05mm and 1 .00mm, even more preferably in the range between 0.10mm and 0.65mm and optimally in the range between 0.20mm and 0.30mm.

[0097] Preferably, but not limitedly, said wires 111 are grouped in a number between 4 and 190, even more preferably in a number between 12 and 64, and optimally in a number between 24 and 48 to form a strand 110.

[0098] Preferably, but not limitedly, the helical winding pitch of the wires 111 of a single strand 110 is between 3 and 40 times, and optimally between 5 and 20 times, the diameter of the strand 110 itself. In some preferred embodiments of the invention, the helical winding pitch of the wires 111 of the strand 110 is equal to 15 times the diameter of the resulting conductor 100. Preferably, but not limited to, the helical winding pitch of the wires 111 of a single strand 110 is between 10mm and 200mm, more preferably between 15mm and 80mm, and even more preferably between 25mm and 40mm.

[0099] Conveniently, all the wires 111 of the same strand 110 are wound helically in a clockwise or counterclockwise direction.

[0100] Preferably, said strands 110 of said conductor 100 wound in a clockwise direction are equal in number to the strands 110 wound in a counterclockwise direction, preferably in a 1 to 1 ratio.

[0101] According to the preferential but non-limiting embodiments illustrated in the attached FIGS. 3 and 4, a conductor 100 is observed comprising eighteen strands 110 wound / braided in a crossed manner with respect to each other in opposite directions (clockwise and anticlockwise) in a 1 :1 ratio (one clockwise and one, adjacent, anticlockwise).

[0102] Preferably, in other possible embodiments of the invention, said strands 110 are reciprocally wound in a crossed manner in opposite directions (clockwise and anticlockwise) in ratios equal to or even greater than 1 :2 or 2: 1.

[0103] Preferably, the braiding pitch of the strands 110 between each other is between 10 mm and 300 mm, more preferably between 40 mm and 100 mm, and even more preferably between 60 mm and 80 mm.

[0104] Preferably, but not limitedly, the braiding density of the strands 110, each of which is obtained by helically winding at least four wires 111 , is such as to define a surface coverage greater than approximately 80%, more preferably greater than approximately 95%.

[0105] Advantageously, as mentioned, the crossed winding (braiding) of the strands 110 of the conductor 100 is made in such a way as to delimit a central channel 120 wherein a cooling fluid 12 flows, capable of dissipating the heat accumulated by the Joule effect in the strands 110.

[0106] Preferably the ratio between the external diameter of the conductor 100 and the diameter of the central channel 120 is in the range between 1.1 and 10, more preferably in the range between 1.5 and 5 and optimally in the range between 2.5 and 3.5.

[0107] According to the preferred but non-limiting embodiments illustrated in the attached FIGS. 5 and 6, a section and a side view of a conductor 100 are shown with eighteen strands 110 wound in a crossed manner around each other in opposite directions in a 1 :1 ratio and in electrical contact with each other.

[0108] Conveniently, each strand 110 is braided with other strands so as to be in direct contact (physical and, therefore, also electrical) with said other strands for most of its longitudinal development. Advantageously, said conductor 100 comprises a central channel 120 and may comprise at least one outer layer 130 arranged externally to said strands 110; said outer layer 130 comprises a layer of electrically insulating material.

[0109] Advantageously, said outer layer 130 is configured to define a barrier to leakages of said cooling fluid 12.

[0110] Preferably, said outer layer 130 comprises a rubber-based material, preferably EPDM rubber-based, or a reticulated elastomeric material.

[0111] According to the preferential but non-limiting embodiments illustrated in the attached FIGS. 5 and 6, said conductor 100 comprises a separating layer 131 interposed between said strands 110 and said external layer 130. Preferably, said separating layer 131 is capable of preventing the penetration of the external layer 130 into the spaces between the strands 110.

[0112] Preferably but not limitedly, said separating layer 131 may be a paper or synthetic material tape between the conductor 100 and the outer layer 130.

[0113] Preferably but not limitedly, said separating layer 131 can be applied on said conductor 100 by taping or by longitudinal application, with total or partial coverage of the external surface of the conductor 100.

[0114] Advantageously, the cross-winding (braiding) of the strands 110 made with helical windings of short-pitch wires 111 provides a structure such that the conductor 100 bent with a radius of curvature of not less than 110 mm (and in any case not less than 8 times its diameter) maintains a minimum cross-section of the central channel 120 for the passage of the cooling fluid 12 greater than or equal to 9mm2i.e. greater than or equal to 80% of the cross-section of the central channel 120 in non-bent conditions. Conveniently, at least one of the said at least six strands 110 thus obtained is wound / braided in a cross-winding manner in the opposite direction between clockwise and anticlockwise with respect to the other strands 110.

[0115] With reference to FIGS. 7 and 8, sectional and perspective diagrams of the crosswinding in opposite directions of said strands 110 are shown. Specifically, in FIG. 8, a crosswinding of first strands 110' represented in black in a clockwise direction (right-handed) and a cross-winding of second strands 110" represented in light grey in an anti-clockwise direction (left-handed) can be observed.

[0116] Advantageously, said cooling fluid 12 laps the strands 110 obtaining a dissipation of the heat accumulated by the Joule effect through direct contact.

[0117] Conveniently, said cooling fluid 12 can be a liquid, more or less viscous, or a gas.

[0118] Preferably, said cooling fluid 12 is a non-polar dielectric fluid (for example but not limited to or binding, it may be a silicone fluid) having a kinematic viscosity between 5cSt and 10,000cSt at 20°C, and optimally between 10cSt and 50cSt at 20°C, with thermal conductivity between 0.020W(m K) and 0.80W(m K), optimal range between 0.14W(m K) and 0.16W(m K) and with specific heat preferably in the range between 0.9kJ / kg°C and 2.0kJ / kg°C and optimally in the range between 1 ,5kJ / kg°C and 1 ,9kJ / kg°C.

[0119] Preferably, according to some preferred embodiments, said cooling fluid 12 may be dry air with a humidity percentage of less than 1 %.

[0120] Said central channel 120 having a diameter preferably between 1 .0mm and 80.0mm, more preferably between 2.0mm and 10.0mm and optimally between 3mm and 6mm. Said conductor 100 is coated by extrusion or by taping with an external layer 130 having a layer of electrically insulating material.

[0121] Preferably, according to a preferential embodiment, said electrically insulating material of the outer layer 130 is of the thermoplastic type.

[0122] Preferably, according to a preferential embodiment, said electrically insulating material of the outer layer 130 is of the thermosetting / elastomeric type.

[0123] Preferably, said outer layer 130 can be made of thermally insulating material.

[0124] Advantageously, said outer layer 130 of electrically and thermally insulating material defines a barrier to leakages of said cooling fluid 12.

[0125] Advantageously, the tubular structure of the conductor 100 which is self-supporting (i.e. it supports itself without requiring internal or additional supports) and also resistant to compression can allow the application of a layer of rubber (or other elastomer which can be reticulated) above said tubular structure. In particular, the structure of the conductor 100 is suitable to resist to externally applied pressure and, therefore, allows the use of rubber as an external coating material for the structure itself since the vulcanization of the rubber occurs under pressure (for example, it can reach up to 20 bar). Advantageously, the use of rubber as an external coating layer - in particular compared to the use of thermoplastic materials - gives greater flexibility and fatigue resistance to the conductor 100, and is also safer since it resists overheating better, and in particular it resists (for limited periods of time) even in situations of abnormal temperatures of up to 250°C.

[0126] The present invention also relates to a flexible charging cable 200 which comprises one or more conductors 100 according to the characteristics reported above.

[0127] In particular, said flexible charging cable 200 comprises at least one casing 210, made of thermoplastic or elastomeric material, with at least one conductor 100 inside.

[0128] Preferably, said casing 210 includes inside it other electrical cables, pipes and / or other similar elements for the conveyance / transport of the cooling fluid 12.

[0129] Preferably, the flexible charging cable 200 may comprise: - one or more tubular elements 220 for the delivery of a cooling fluid 12 and one or more conductors 100 for the return of a cooling fluid 12 from and to a cooling unit 520 of said cooling fluid 12, and / or

[0130] - one or more conductors 100 for the delivery of a cooling fluid 12 and one or more tubular elements 220 for the return of a cooling fluid 12 from and to a cooling unit 520 of said cooling fluid 12, and / or

[0131] - one or more first conductors 100 for the delivery of a cooling fluid 12 and one or more second conductors 100 for the return of a cooling fluid 12 from and to a cooling unit 520 of said cooling fluid 12.

[0132] Preferably, according to a possible preferential embodiment, said flexible charging cable 200 comprises one or more tubular delivery elements 220 and one or more return conductors 100 from and to a cooling unit 520 of said cooling fluid 12.

[0133] According to a preferred but non-limiting embodiment of the present invention, FIG. 9 shows a diagram of a path of a cooling fluid 12 (said cooling fluid 12 not being shown in FIG. 9 but its path being shown by the black and grey arrows) in a system 500 according to the present invention, wherein the arrows are indicative of the path followed by the cooling fluid which starts from a cooling unit 520, is fed into a conductor 100 - and in particular into the central channel 120 of the conductor 100 - through a connector 400 and then returns to said cooling unit 520 through a tubular element 220 which intercepts the flow of the cooling fluid 12 exiting the conductor 100 in a plug 600.

[0134] Conveniently, the electric vehicle charging system 500 includes:

[0135] - at least one flexible charging cable 200;

[0136] - a connector 400 to allow the passage of electric current in the strands 110 of at least one conductor 100 of said flexible charging cable 200 and the passage of the cooling fluid 12 in the central channel 120 of at least one conductor 100 of said flexible charging cable 200;

[0137] - a plug 600 for mechanically connecting said flexible charging cable 200 to an electrical energy storage system;

[0138] - at least one electrical energy conversion device 510 capable of converting electrical energy to feed it into said flexible charging cable 200;

[0139] - at least one cooling unit 520 suitable for cooling said cooling fluid 12.

[0140] Preferably, said system 500 comprises at least one flexible charging cable 200, a connector 400 that allows the passage of electric current in each conductor 100 and the passage of the cooling fluid 12 in the central channel 120 of each conductor 100, a plug 600 for each flexible charging cable 200 that connects it to an electrical energy storage system, at least one electrical energy conversion device 510 capable of converting electrical energy from a public or private electrical network to feed it into said flexible charging cable 200 and at least one cooling unit 520 suitable for cooling said cooling fluid 12, comprising a device for controlling the flow rate of the cooling fluid and being in fluid communication with said connectors 400 and with the related conductors 100. Conveniently, the plug 600 contains the contacts 610 for connecting the flexible charging cable 200 to the electrical energy storage system to be recharged.

[0141] According to a preferred but non-limiting embodiment of the present invention, FIG. 15 shows a cross-section of a flexible charging cable 200 with two conductors 100 providing central return channels 120 for the cooling fluid 12 and two tubular delivery elements 220. Ideally, in the embodiment shown in FIG. 15, a first tubular element 220 is a delivery element for the cooling fluid 12 which returns via a first conductor 100, and similarly the other tubular element 220 is a delivery element for the cooling fluid 12 which then returns via the other conductor 100.

[0142] According to another preferential but non-limiting embodiment of the present invention, FIG. 16 shows the cross-section of a flexible charging cable 200 with two conductors 100 suitable for providing central return channels 120 for the cooling fluid 12 and a single tubular delivery element 220.

[0143] Preferably, according to another preferential embodiment, said flexible charging cable 200 comprises one or more conductors 100 which are for delivery and one or more tubular elements 220 which are for return from and to a cooling unit 520 of said cooling fluid 12.

[0144] According to another preferential but non-limiting embodiment of the present invention, FIG. 17 shows the cross-section of a flexible charging cable 200 with two conductors 100 suitable for providing central delivery channels 120 for the cooling fluid 12 and two tubular return elements 220. FIG. 17 also shows a grounding cable 230 included within the casing 210 of the flexible charging cable 200.

[0145] According to another preferential but non-limiting embodiment of the present invention, FIG. 18 shows a cross-section of a flexible charging cable 200 with two conductors 100 providing central delivery channels 120 for the cooling fluid 12 and two tubular return elements 220. FIG. 18 also shows a grounding cable 230 included within the casing 210 of the flexible charging cable 200 and two pilot conductors 240.

[0146] According to the preferential but non-limiting embodiment of the present invention shown in FIG. 18, said flexible charging cable 200 has two casings 210.

[0147] Preferably, according to yet another preferential embodiment, said flexible charging cable 200 comprises one or more conductors 100 which are for delivery and one or more conductors 100 which are for return from and to a cooling unit 520 of said cooling fluid 12. In some preferred embodiments of the present invention, said cooling unit 520 is a cooling source internal to a charging box.

[0148] In other embodiments of the present invention, said cooling unit 520 is a cooling source external to a charging box. Said charging box comprising said flexible charging cable 200 and said electrical energy conversion device 510.

[0149] Advantageously, said flexible charging cable 200 may comprise additional elements which are arranged within said casing 210 and / or said outer layer 130 and which are adapted to provide mechanical, electrical and / or anti-torsion protection.

[0150] Preferably but not limitedly, said casing 210 is made of one or more layers of polyurethane sheath.

[0151] Advantageously, the flexible charging cable 200 comprises a connector 400 for each conductor 100. Said connector 400 is adapted to connect a conductor 100 to an electrical energy conversion device 510 which converts electrical energy from a public or private network for input into said flexible charging cable 200 and to a cooling unit 520 which cools the cooling fluid 12.

[0152] Said electrical energy conversion device 510 is suitable for transforming alternating current into direct current or direct current into alternating current, by way of example but not limitation with an output voltage of 1000V into DC with an output of 500kW.

[0153] Preferably, said connector 400 also comprises a hollow cylinder 410 and a hollow fitting 420. Said hollow cylinder 410 comprises a threaded internal portion and a smooth internal portion.

[0154] Preferably, said connector 400, in other preferred embodiments of the present invention, as shown in FIGS. 10 and 11 , also comprises:

[0155] - a hollow cylinder 410 whose internal wall is in contact with said strands 110; said hollow cylinder 410 is designed to allow the passage of current in said strands 110;

[0156] - a hollow internal tube 430 suitable for insertion into said central channel 120;

[0157] - a hollow fitting 420 which fits onto the outer wall of said hollow cylinder 410 and which connects to the inner portion of said internal tube 430.

[0158] Advantageously, in these embodiments, the connector 400 can be used inside a plug 600 for connecting said flexible charging cable 200 to said electrical energy storage system. Said plug 600, shown in detail in FIGS. 12 and 13, has contacts 610 for connection to an electrical energy storage system.

[0159] Preferably, said connector 400, in other embodiments of the present invention, also comprises:

[0160] - a hollow cylinder 410 comprising a threaded internal portion and a smooth internal portion, and wherein the internal portion of said hollow cylinder 410 is in contact with said strands 110; said hollow cylinder 410 is suitable for allowing the passage of current in said strands 110;

[0161] - a hollow fitting 420 screwed into said hollow cylinder 410; said hollow fitting 420 is adapted to allow the passage of said cooling fluid 12 into said central channel 120.

[0162] Advantageously, said hollow fitting 420 has a tip suitable for insertion into said central channel 120 to allow the passage of said cooling fluid 12 (shown with arrows in FIG. 9 identifying its path) from said cooling unit 520 to said central channel 120.

[0163] Advantageously, as shown in the preferred embodiment of FIGS. 11 and 13, said contacts 610 are connected directly to said connector 400 inside the plug 600.

[0164] Said hollow fitting 420 is suitable for connection to pipes connected to said cooling unit 520 via hydraulic joints the use of which is believed to be known to a person skilled in the art.

[0165] Advantageously, said cooling unit 520 is in fluid communication with said connectors 400 and with the related conductors 100 of said flexible charging cable 200.

[0166] Advantageously, said cooling unit 520 comprises a flow control device for the cooling fluid 12 and at least two temperature control devices for the cooling fluid 12, one on the delivery connection and the other on the return connection to the cooling unit 520.

[0167] Preferably, in some embodiments of the invention, said flow control device is a pump. Said pump is suitable for controlling the flow rate through automatic timed on-off cycles.

[0168] Preferably, in some embodiments of the invention, said flow control device is a pump. Said pump is suitable for controlling the flow rate through on-off cycles commanded by the presence of power supplied by element 510.

[0169] Preferably, in some embodiments of the invention wherein said cooling fluid 12 is air, said flow control device is a valve suitable for allowing the escape of air. Said valve suitable for controlling the flow of air by opening and closing with automated timed cycles.

[0170] Conveniently, at least one flexible charging cable 200, at least one device 510, at least one cooling unit 520 realize an electric vehicle charging system 500 according to the present invention.

[0171] Preferably, but not limitedly, according to a possible preferential embodiment, said strand 110 has a diameter of 1 6mm and comprises forty-six copper conductor wires 111 of 0.20mm in diameter helically wound with a pitch of 40 mm and in a clockwise direction. Starting from the strand 110 thus constructed, a conductor 100 can in turn be constructed by winding said strands 110 in a crossed manner (braiding) in alternating directions on the same plane in a single layer 12 (clockwise) + 12 (anticlockwise) with alternating directions between them with a pitch of 60 mm. In this way, a crossed winding of strands 110 is obtained which defines a conductor 100 with an overall diameter of approximately 9mm, with a central channel 120 of 5mm in diameter. An insulating material, such as but not limited to an EPDM rubber-based material, is extruded onto the crossed winding of strands 110 to form the external layer 130 of said conductor 100. The conductor 100 thus formed has a nominal cross-section of 35mm2, the present invention can be applied to obtain final sections different from the one described here starting from elements which are different and not limited to those described above also for the realization of the same section described here.

[0172] Preferably, but not limitedly, according to another preferential embodiment, said conductor 100 comprises a number between 6 and 48 of strands 110 with a pitch such as to form an angle preferably but not limitedly between 25° and 45° with respect to the axis along the section and the longitudinal direction of the conductor 100. Each strand 110 is formed by a number of wires 111 between 30 and 48, with a helical winding pitch equal to 15 times the diameter of the strand 110, used preferably but not limitedly in number of 6 to 48.

[0173] What is illustrated in the figures is merely exemplifying and a person skilled in the art may carry out variations or modifications that do not depart from the spirit and scope of the invention. It is understood that such variations and modifications are included in the scope of the description and claims.

[0174] TEST

[0175] Referring to FIG. 19, a diagram resulting from a laboratory test on a prototype conductor 100 with an external layer 130, according to the present invention, is shown. Said diagram is suitable for showing the thermal power dissipated (Premoved) by the cooling fluid 12 and the temperature measured during the test execution time.

[0176] The temperature was measured for the cooling fluid 12 exiting the conductor 100 (T(°C) outlet. oil in FIG. 19), on the outer surface of the outer layer 130 of the conductor 100 (T(°C) insulating. surface in FIG. 19) and for the cooling fluid entering the conductor 100 (T(°C) inlet.oil in FIG. 19).

[0177] A conductor 100 of 8 meters length was tested. The choice of this length was based on an analysis of the state of the art wherein various manufacturers of ultra-fast charging technologies for electric vehicles generally provide charging cable lengths between 4 meters and 7.5 meters. The length of the conductor 100 was chosen to cover almost all currently existing cables.

[0178] An electrically insulating silicone oil was used as the cooling fluid 12, characterized by a kinematic viscosity of 10cSt and a specific heat of approximately 1.7 kJ / kg°C (data at room temperature). The inlet cooling fluid 12 was maintained at room temperature in a tank for the entire duration of the test, the temperature of the cooling fluid 12 exiting the conductor 100 under test was measured at discrete time intervals throughout the duration of the test. For the hydraulic simulation of the 520 cooling unit, an oil pump with a maximum head of 2 bar and a maximum flow rate of 5 liters / minute was used, suitable for use with oils having viscosity up to 600cSt. The pump was combined with a system of special pressure and flow regulators and reducers and fluid ducts. With this experimental setup, the fluid flow rate through the conductor under test was measured at discrete time intervals during the test.

[0179] The average data obtained from the test is approximately 1.1 kg / minute or 0.02 kg / s at a pump head of approximately 1.1 -1.2 bar.

[0180] It should be noted that almost all charging cables consist of two conductors, each up to 7.5 metres long, and that each charging station generally uses two charging cables, which are generally cooled by a single cooling unit 520. The cooling units 520 currently available on the market for ultra-fast electric charging stations can generally handle flow rates of up to 10 kg / minute and heads in the 5-10 bar range.

[0181] The flow rate and pump head conditions characteristic of this test, if re-scaled for four 100 conductors (two 8-meter flexible 200 charging cables with two 100 conductors each), are approximately 4.4 liters / minute and 4.8 bar. Therefore, the specific working conditions of this test are easily reproducible with normal commercial 520 cooling units. To simulate the electric charging, an AC / DC conversion system capable of continuously supplying a current greater than 500 A was used, specifically the average current that passed through the conductor, measured at discrete time intervals during the test, was 520 A.

[0182] As shown in FIG. 19, under the conditions described above, after approximately 120 seconds from the start of the test, i.e. after approximately 120 seconds from the start of the flow of cooling fluid 12 through the conductor 100 being tested and from the supply of a current equal to 520A always through the conductor 100 being tested, a condition of equilibrium of the heat exchange that occurred between the conductor 100, the cooling fluid 12 and the external environment was reached.

[0183] The maximum temperature reached on the surface of the outer layer 130 covering the conductor 100 was approximately 56°C, which is lower than the maximum temperature (equal to 60°C) permitted by the regulations on the surface of the outer layer 130 of the conductor 100.

[0184] The thermal power dissipated by the cooling fluid 12 under equilibrium conditions, calculated as Pdiss =(flow rate) • c • AT , where “c” is the specific heat of the cooling fluid and AT is the temperature difference between the cooling fluid 12 entering and exiting the conductor 100, was approximately 1.15 kW.

[0185] Commercially available cooling units 520, which can be used in ultra-fast electric charging stations, typically feature a cooling power in the 4-6 kW range. The characteristic heat dissipation power of this test, when re-scaled for four 100 conductors (two 8-meter 200 flexible charging cables with two 100 conductors each), is approximately 4.6 kW, which is easily reproducible with popular commercial cooling units 520.

[0186] Considering the lengths and currents used in this test and the results obtained, using common cooling units 520, it is possible to both reduce the power of the cooling unit 520 required for this solution, compared to solutions already on the market, and further increase the current supplied (and therefore the power that can be supplied with this system).

[0187] Compared to the state of the art, it has also been verified, for the system 500 in question, that the flow of the cooling fluid 12 is little influenced by the bending of the conductor 100 (CN113851269A and in DE202015009531 U1 ) and, advantageously, the conductor 100 offers both an improved exchange surface between the conductor itself (set of strands 110) and the cooling fluid 12 (also compared to WO2022217432A1 and EP3882929A1), as well as greater flexibility.

[0188] Advantageously, the fact of placing the flow of the cooling fluid 12 in direct contact with the electrically conductive material (conductive metal) of the strands 110 allows the use of currents that go beyond 500A and, preferably, allows reaching 800A, obtaining a significantly improved efficiency compared to previous solutions wherein this did not occur (WO2022226730A1 , CN106782835A, US6100467A, CN114464363A, CN216623868U, CN112289497A)

[0189] Advantageously, from a construction point of view, the conductor 100 can be produced / achieved with machines for the production of cables and their components known to the state of the art, thus also resulting in a cheaper solution to produce compared to solutions known to the art.

[0190] Preferably, the conductor 100 can be made in two stages by placing in series / sequence a stranding machine and a braiding machine. In particular, the present invention also relates to a method of making the conductor 100 wherein the following are used in sequence:

[0191] - a stranding machine, for helically winding together at least four wires 111 of electrically conductive material and thus obtaining each strand 110, and

[0192] - a braiding machine, for braiding the strands 110 thus obtained so as to define said self- supporting tubular structure which is free of internal elements and which is provided with said central channel 120 wherein a cooling fluid 12 flows in use which laps said strands 110. I deally, downstream of the braiding machine, the application of the external layer 130 of electrically insulating material can be provided by means of an extrusion and vulcanization line.

[0193] Advantageously, the conductor 100 allows for a reduction in size (external diameter) and weight of the corresponding electric charging cable comprising said conductor, in particular compared to the electric charging cables currently on the market and known in the state of the art.

Claims

1 . Conductor (100) with longitudinal development for a flexible electric charging cable (200), said conductor is characterised in that it comprises at least six strands (110) braided in such a way as to define a self-supporting tubular structure, which is free of internal elements, with a central channel (120) wherein a cooling fluid (12) flows in use which laps said strands (110), each of said strands (110) being made with at least four wires (111) of an electrically conductive material wound together in a helical manner, at least one of said six strands (110) being braided in the opposite direction to the other strands (110).

2. Conductor (100), according to claim 1 , wherein said conductor comprises at least one outer layer (130) disposed externally to the strands (110), and wherein said outer layer (130) comprises a layer of electrically insulating material.

3. Conductor (100) according to claim 2, wherein said at least one outer layer (130) is configured to define a barrier to leakages of said cooling fluid (12).

4. Conductor (100) according to claims 2 or 3, wherein said at least one outer layer (130) is made of thermally insulating material.

5. Conductor (100) according to one or more of the preceding claims, wherein said conductor comprises at least one external layer (130) arranged externally to the strands (110) and a separator layer (131) interposed between said external layer (130) and said strands (110).

6. Conductor (100) according to one or more of the preceding claims, wherein said conductor comprises at least one outer layer (130) arranged externally to the strands (110), and wherein said outer layer (130) comprises a rubber-based material, preferably based on EPDM rubber, or a reticulated elastomeric material.

7. Conductor (100) according to one or more of the preceding claims, wherein said strands (110) wound in a clockwise direction are equal in number to the strands (110) wound in a counterclockwise direction.

8. Conductor (100) according to one or more of the preceding claims, wherein:- said braided strands (110) are in a number equal to or between 6 and 48,- each strand (110) is made by helically winding a number of wires (111 ) equal to or between 4 and 64.

9. Conductor (100) according to one or more of the preceding claims, wherein said clockwise wound strands (110) are in a 1 to 1 ratio with the counterclockwise wound strands(110).

10. Conductor (100) according to one or more of the preceding claims, wherein said wires(111) have a diameter included in the range between 0.05mm and 1 .00mm.

11. Conductor (100) according to one or more of the preceding claims, wherein the helical winding pitch of the wires (111 ) of the strand (110) is included between 3 and 40 times the diameter of the strand (110) itself.

12. Conductor (100) according to one or more of the preceding claims, wherein the helical winding pitch of the strand (110) is equal to 15 times the diameter of the conductor itself.

13. Conductor (100) according to one or more of the preceding claims, wherein the ratio between the external diameter of the conductor (100) and the diameter of the central channel (120) is included in the range between 1.1 and 10.

14. Conductor (100) according to one or more of the preceding claims, wherein said central channel (120) has a diameter preferably included between 1.0mm and 80.0mm.

15. Conductor (100) according to one or more of the preceding claims, wherein said strands (110) are braided with a pitch such as to form an angle of approximately 25° - 45° with respect to the longitudinal development direction of the conductor (100).

16. Conductor (100) according to one or more of the preceding claims, wherein said strands (110) are braided in alternating directions in a single plane.

17. Conductor (100) according to one or more of the preceding claims, wherein said conductor comprises a single layer with strands (110) braided in alternating directions.

18. Conductor (100) according to one or more of the preceding claims, wherein the helical winding pitch of the wires (111 ) of a single strand (110) is between 10mm and 200mm, preferably between 15mm and 80mm, and more preferably between 25mm and 40mm.

19. Conductor (100) according to one or more of the preceding claims, wherein the braiding pitch of the strands (110) between them is between 10 mm and 300 mm, preferably between 40 mm and 100 mm, and more preferably between 60 mm and 80 mm.

20. Method for making a conductor according to one or more of the preceding claims, wherein the following are used in sequence:- a stranding machine, for helically winding together at least four wires (111 ) of electrically conductive material and thus obtaining each strand (110), and- a braiding machine, for braiding the strands (110) thus obtained so as to define said self- supporting tubular structure which is free of internal elements and which is provided with said central channel (120) wherein a cooling fluid (12) flows in use which laps said strands (110).

21. Flexible charging cable (200) comprising at least one casing (210) with at least one conductor (100) inside according to one or more of the previous claims.

22. Cable according to the previous claim, wherein said cable comprises said at least one conductor (100) and one or more elements (220) such as electrical cables, pipes and / or other elements for the transport of the cooling fluid (12).

23. Cable according to one or more of the preceding claims, wherein said cable comprises:- one or more tubular elements (220) for the delivery of a cooling fluid (12) and one or more conductors (100) for the return of a cooling fluid (12) from and to a cooling unit (520) of said cooling fluid (12), and / or- one or more conductors (100) for the delivery of a cooling fluid (12) and one or more tubular elements (220) for the return of a cooling fluid (12) from and to a cooling unit (520) of said cooling fluid (12), and / or- one or more first conductors (100) for the delivery of a cooling fluid (12) and one or more second conductors (100) for the return of a cooling fluid (12) from and to a cooling unit (520) of said cooling fluid (12).

24. Cable according to one or more of the preceding claims, wherein said cable further comprises one or more additional elements, arranged inside said casing (210) and / or said external layer (130), suitable for providing mechanical, electrical and / or anti-torsion protection.

25. Electric vehicle charging system (500) comprising:- at least one flexible charging cable (200) according to one or more of the preceding claims;- at least one connector (400) to allow the passage of electric current in the strands (110) of at least one conductor (100) of said flexible charging cable (200) and the passage of the cooling fluid (12) in the central channel (120) of at least one conductor (100) of said flexible charging cable (200);- a plug (600) for the mechanic connection of said flexible charging cable (200) to an electrical energy storage system;- at least one electrical energy conversion device (510) capable of converting electrical energy for input into said flexible charging cable (200);- at least one cooling unit (520) suitable for cooling said cooling fluid (12).

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