Electric charging cable for a motor vehicle

Abstract

Electric charging cable for a motor vehicle (12), with two electrically conductive conductors (16) which are each connected at their opposite axial ends to an electrical connection (18, 20) in order to electrically contact the electrically conductive conductor (16) with a charging station (14) and the motor vehicle (12) and to transfer electrical energy to an electrical energy storage device of the motor vehicle (12), wherein the two electrically conductive conductors (16) form different poles of the electric charging cable, with two insulating layers (22), wherein each of the two electrically conductive conductors (16) is surrounded by one insulating layer (22), with two first coolant channels (24) in which a cooling fluid (28) can be guided to cool the respective electrically conductive conductor (16), wherein the respective insulating layer (22) is spaced apart from the respective electrically conductive conductor (16) and the respective first coolant channel (24) between the respective insulating layer (22) and the respective electrically conductive conductor (16) is designed such that the cooling fluid (28) flows directly around the respective electrically conductive conductor (16), wherein the electric charging cable further comprises a sheathing layer (30) which surrounds the insulating layers (22) of the two conductors (16), wherein the sheathing layer (30) is spaced apart from the insulating layers (22) and a second coolant channel (32) is formed between the sheathing layer (30) and the insulating layers (22), wherein by connecting the two of the first coolant channels (24), which form a coolant supply, and the second coolant channel (32), which forms a coolant return, at one axial end, a circulating cooling system for the electrically conductive conductors (16) is realized, which can be supplied with cooling medium from the charging station (14), wherein the electrical charging cable has a first pressure sensor (36) which is arranged in the second coolant channel (32) to detect a pressure drop in the coolant channel (32) and thus in the coolant return, wherein a second pressure sensor (38) is arranged in each of the two first coolant channels (24) in order to locate a leak in either the respective insulation layer (22) or in the jacket layer (30) by detecting a pressure difference between the first pressure sensor (36) and the respective second pressure sensor (38).

Description

[0001] The present invention relates to an electric charging cable for a motor vehicle.

[0002] In the field of electrical power transmission, and particularly in the field of charging cables for motor vehicles, electrical conductors are typically arranged within a sheathed cable. In addition to the individually insulated electrical conductors, plastic core conductors are incorporated to ensure the sheath's circular shape. Due to the multiple layers of insulation and the core conductors within the sheath, the dissipation of heat generated in the conductors is limited. Consequently, when transmitting high electrical power, especially during vehicle charging, this can lead to overheating of the conductors and the charging cable in general.

[0003] To improve the cooling of an electric charging cable for motor vehicles, it is known, for example, from DE 199 21 310 A1, to form a cooling channel in the electrical conductor of the charging cable, through which a cooling medium can flow in order to dissipate heat loss from the electrical conductors.

[0004] The disadvantage is that the arrangement of the coolant channel in the electrical lines is complex, and the additional insulation of the coolant channel and the electrical lines results in low heat transfer between the electrical lines and the cooling medium.

[0005] US 2013 / 0267115A1 shows a cable arrangement with two electrical conductors, each of which is surrounded by an insulating layer. In one electrical conductor, a channel is formed centrally within the conductor. In the other electrical conductor, a total of three channels are shown. One channel is located on the outer surface of the insulating layer. Another channel is independent of the insulating layer and runs parallel to it. A further channel is a protrusion of the insulating layer. The two conductors with their insulating layers are surrounded by a common outer sheath, the space between the sheath and the insulating layers defining a channel.

[0006] US 2015 / 0217654A1 shows a cable arrangement with a U-shaped loop that is part of a cooling channel.

[0007] US 5,591,937 A discloses a charging cable for an electric vehicle. A cooling channel is centrally integrated into an inner dielectric layer. The inner dielectric layer is surrounded by another dielectric layer, to which an outer conductor is attached. The outer conductor is surrounded by an outer dielectric layer, into which grooves are formed that create further cooling channels.

[0008] DE 23 22 085 A shows a fluid-filled telecommunications cable in which leakage faults can be detected and classified. For this purpose, lines 4a are provided along the cable within the charging cable for measuring the pressure at different points along the cable. These lines have measuring ports at the corresponding measuring points.

[0009] US 2010 / 0 277 127 A1 reveals further state of the art.

[0010] It is therefore the object of the present invention to provide an improved electric charging cable for a motor vehicle which enables improved cooling of electrical conductors and localization of leakage with minimal technical effort.

[0011] This problem is solved by an electric charging cable according to claim 1.

[0012] The electric charging cable has two conductors, each with an insulating layer, forming different poles of the electric charging cable, wherein the respective insulating layer is spaced away from the respective conductor and the respective first coolant channel between the respective insulating layer and the respective conductor is designed in such a way that the cooling fluid flows directly around the respective conductor, and that a circulating cooling system for the conductors is implemented, which can be supplied with cooling medium from the charging station.

[0013] The electrically conductive conductors are not separately insulated, so that the cooling fluid in the respective first coolant channel can flow directly around the respective electrical conductor or electrical conductors of the respective electrical conductor, or directly touch the current-carrying conductors of the respective electrical conductor, so that direct heat transfer from the respective electrical conductor to the cooling fluid is possible.

[0014] Because the cooling fluid flows directly around the respective electrical conductor, the heat transfer between the cooling medium and the respective electrical conductor or the electrical conductors of the respective electrical conductor can be improved, since no electrical insulation of the electrical conductors has to be overcome by the heat flow and a direct conventional heat transfer between the electrical conductors and the cooling fluid is ensured.

[0015] The electric charging cable can therefore be provided with improved heat dissipation and with minimal technical effort.

[0016] Between each insulating layer and each conductor, a first cavity is formed, which constitutes the first coolant channel. Because the first coolant channel is formed simply by a cavity between the insulating layer and the electrical conductor, and no separate coolant channel is required, the technical complexity for the first coolant channel and for the overall electrical wiring arrangement can be significantly reduced.

[0017] According to claim 1, the electric charging cable further comprises a sheath layer that circumferentially surrounds the insulating layers, wherein the sheath layer is spaced apart from the insulating layers and a second coolant channel is formed between the sheath layer and the insulating layers. The respective first coolant channel is connected to the second coolant channel at an axial end. This allows the cooling fluid to be guided in a closed system throughout the entire cable assembly, thus enabling defined cooling of the electrically conductive conductors.

[0018] According to claim 1, the first two coolant channels form a coolant supply and the second coolant channel forms a coolant return. This allows the cooling fluid to be supplied to the electrically conductive conductors under cooled conditions and returned via the second coolant channel, thus achieving a defined coolant circulation.

[0019] In a preferred embodiment, the electrical charging cable has a connector at at least one axial end to electrically contact the electrically conductive conductors, wherein the connector connects the first coolant channel to the second coolant channel. This allows the first coolant channel to be connected as the supply to the second coolant channel as the return, so that a defined coolant circulation can be provided with minimal technical effort.

[0020] In a preferred embodiment, the electrical charging cable has a connector at at least one axial end for electrically contacting the electrically conductive conductors, wherein the connector has an opening that is connected to the second coolant channel for draining the coolant from the electrical conductor arrangement. This allows a coolant flow to be generated in the second coolant channel and the coolant to be drained from the second coolant channel with minimal technical effort. In a preferred embodiment, the electrical charging cable has a connector at at least one axial end for electrically contacting the electrically conductive conductors, and wherein the connector is connectable to a coolant arrangement for supplying the coolant to the two first coolant channels.This allows cooled cooling fluid to be supplied to the first two coolant channels via the coolant arrangement, thereby improving the overall cooling performance of the electric charging cable.

[0021] According to claim 1, the electrical charging cable has a pressure sensor arranged in the second coolant channel to detect a pressure drop in the second coolant channel. This allows a leak in the coolant channel to be detected with minimal technical effort, thereby enabling early detection of a malfunction in the cooling system as a whole.

[0022] According to claim 1, a second pressure sensor is arranged in each of the first two coolant channels to determine the location of damage to the coolant channel, such that a leak in either the respective insulation layer or the jacket layer can be located by detecting a pressure difference between the first pressure sensor and the respective second pressure sensor. This allows a leakage location in the coolant channel to be detected and determined with minimal technical effort, thereby enabling the localization of a leak and its corresponding repair with minimal technical effort.

[0023] Overall, the present electric charging cable can provide improved cooling of the electrical conductors and the localization of leaks with minimal technical effort. The cooling fluid flows directly around the electrical conductors, and the heat flow is not impeded by insulation. At the same time, the technical complexity is significantly reduced by spacing the insulation layer from the electrical conductor and by the cooling channel formed between them, which acts as a coolant line.

[0024] Exemplary embodiments of the invention are shown in the drawing and are explained in more detail in the following description. They show: Fig. 1 a schematic representation of an electric charging cable which electrically connects an electrically powered motor vehicle to a charging station; Fig. 2 a schematic cross-sectional view of an electric charging cable not according to the invention with a coolant channel; Fig. 3 a schematic cross-sectional view of an embodiment of the electric charging cable according to the invention with two coolant channels; and Fig. 4 a schematic view of a longitudinal section of the electric charging cable according to a second embodiment Fig. 3.

[0025] In Fig. Figure 1 is a schematic representation of an electrical wiring arrangement, generally designated by 10. The electrical wiring arrangement 10 forms a charging cable for a motor vehicle 12 and connects the motor vehicle 12 to a charging station 14 in order to charge an electrical energy storage device of the motor vehicle 12 at the charging station 14.

[0026] The electrical wiring arrangement 10 generally comprises an electrically conductive conductor 16, which is connected at its opposite axial ends to an electrical terminal 18, 20 or a plug 18, 20 or connector 18, 20, respectively, in order to electrically connect the electrically conductive conductor 16 to the charging station 14 and the motor vehicle 12 and accordingly to transfer electrical energy to the electrical energy storage device of the motor vehicle 12. The electrical wiring arrangement 10 further comprises an insulating layer 22, which completely surrounds the electrically conductive conductor 16 and thus provides electrical insulation from the environment. The insulating layer 22 is spaced apart from the electrically conductive conductor 16, so that a cavity is formed between the electrically conductive conductor 16 and the insulating layer 22.The cavity forms a coolant channel 24 in which a cooling fluid is guided or can be guided to cool the electrically conductive conductor 16. The electrically conductive conductor 16 has no electrically insulating sheathing, so that the cooling fluid in the coolant channel 24 flows directly around the electrically conductive conductor 16 or directly touches the current-carrying strands of the conductor 16, and accordingly a direct convective heat transfer is formed between the cooling fluid and the electrical conductor 16.

[0027] Because the cooling fluid is formed in the cavity between the insulating layer 22 and the electrically conductive conductor 16, the technical effort required to provide the coolant channel 24 can be significantly reduced, and at the same time the dissipation of the waste heat from the electrically conductive conductor 16 can be significantly improved.

[0028] The electrically conductive conductor 16 is connected at its axial ends to the respective electrical connection 18, 20 or connector 18, 20 in order to connect the electrical conductor arrangement 10 to the charging station 14 and the motor vehicle 12 accordingly.

[0029] The cooling fluid, which in a preferred embodiment is formed by cooled or uncooled ambient air, is preferably supplied to the coolant channel 24 by the charging station 14 and can be discharged at the plug 20 through an opening or returned to the charging station 14 via a second coolant channel not shown here, as will be explained in more detail below.

[0030] In Fig. Figure 2 shows a schematic sectional view of an electrical conductor arrangement 10 that does not conform to the invention.

[0031] The electrical conductor arrangement 10 comprises the conductor 16, which is formed from a plurality of electrically conductive strands, preferably metal or copper strands. The insulating layer 22 surrounds the conductor 16 completely and is spaced apart from it, so that a cavity 26 is formed in the radial direction between the conductor 16 and the insulating layer 22. The cooling medium 28 is guided in the cavity 26 and flows around the conductor 16, thus forming a convective heat transfer between the conductor 16 and the cooling medium 28. The conductor 16 is not insulated from the cooling medium, so that the cooling medium 28 flows directly around the metallic or copper strands. This allows for particularly good heat transfer between the conductor 16 and the cooling medium 28, enabling effective cooling of the conductor 16.

[0032] The cooling medium 28 can be formed from cooled or uncooled ambient air or can be designed as a circulating cooling liquid.

[0033] In Fig. Figure 3 shows a cross-sectional representation of an embodiment of an electrical conductor arrangement 10 according to the invention. Identical elements are designated with the same reference numerals, and only the special features are explained here.

[0034] The electrical conductor arrangement 10 comprises two conductors 16, each with an insulating layer 22, which are arranged parallel to each other and form different conductors or different poles of the electrical conductor arrangement 10. The insulating layers 22 of the two conductors 16 are completely surrounded by a sheathing layer 30, which forms an outer shell of the electrical conductor arrangement 10. The sheathing layer 30 is spaced apart from the insulating layers 22 of the conductors 16, so that a second cavity 32 is formed between the sheathing layer 30 and the insulating layers 22.

[0035] In this arrangement, the first cavities 28 between the insulation layers 22 and the respective conductors 16 form a supply line for the cooling medium 28, and the second cavity 32 forms a return line for the cooling medium 28, as shown in Fig. Figure 3 shows the cavities 26 between the insulation layers 22 and the respective conductors 16. These cavities are connected at one axial end at one of the connectors 18, 20, so that the cooling medium 28 can be pumped through the cavities 26, 32. This enables a circulating cooling system for the conductors 16, which can be supplied with cooling medium from one side, such as the charging station 14.

[0036] In Fig. Figure 4 shows a schematic sectional view of the electrical wiring arrangement 10 in a longitudinal section. Identical elements are designated with the same reference symbols, with only the special features being explained here.

[0037] The electrical wiring arrangement 10 includes a conductor 16 within the sheathing layer 30, which is surrounded by the insulating layer 22. The cooling medium 28 is carried as a supply line in the cavity 26, and the cooling medium 28 is carried as a return line in the second cavity 32 located between the sheathing layer 30 and the insulating layer 22. The wiring arrangement 10 is connected to the connector 20, which contains a supply tap 34 connected to the cavity 26. This tap allows the cooling medium 28 to flow out of the cavity 26 and into the second cavity 32 located between the insulating layer 22 and the sheathing layer 30. This enables the supply line in the cavity 26 to be connected to the return line in the second cavity 32, thus allowing the cooling medium 28 to be circulated within the electrical wiring arrangement 10.This allows cooled cooling medium 28 to flow around the conductor(s) 16 and absorb the heat accordingly, which is then returned via the second cavity 32.

[0038] Furthermore, the plug 20 has an electrical contact 40 for the conductor 16 in order to electrically connect the electrical wiring arrangement 10 to the motor vehicle 12 or the charging station 14.

[0039] In an alternative embodiment, the connector 20 can have an opening through which the cooling medium is guided out of the cavity 26 and disposed of accordingly. It is particularly preferred if the cooling medium 28 is ambient air, so that the conductor 16 is cooled by the drawn-in ambient air and the warmed cooling air is then discharged back into the environment through the opening in the connector 20. This allows for cooling with particularly low technical effort.

[0040] In a preferred embodiment, the charging station 14 has a coolant arrangement that provides the cooling medium 28 and introduces it into the cavity 26, and optionally receives the returned cooling medium and returns it to the cavity 26 in a cooled state. This enables effective cooling of the conductors 16 by pumping the cooling medium 28.

[0041] A pressure sensor is arranged in each of the cavities 26 and 32 to measure the pressure in the cooling system and to detect a leak in the insulation layer 22 or the jacket layer 30. A leak in the insulation layer 22 or the jacket layer 30 can be identified and located by detecting a pressure difference between the pressure sensors 36 and 38.

Claims

[1] Electric charging cable for a motor vehicle (12), with two electrically conductive conductors (16) which are each connected at their opposite axial ends to an electrical connection (18, 20) in order to electrically contact the electrically conductive conductor (16) with a charging station (14) and the motor vehicle (12) and to transfer electrical energy to an electrical energy storage device of the motor vehicle (12), wherein the two electrically conductive conductors (16) form different poles of the electric charging cable, with two insulating layers (22), wherein each of the two electrically conductive conductors (16) is surrounded by one insulating layer (22), with two first coolant channels (24) in which a cooling fluid (28) can be guided to cool the respective electrically conductive conductor (16), wherein the respective insulating layer (22) is spaced apart from the respective electrically conductive conductor (16) and the respective first coolant channel (24) between the respective insulating layer (22) and the respective electrically conductive conductor (16) is designed such that the cooling fluid (28) flows directly around the respective electrically conductive conductor (16), wherein the electric charging cable further comprises a sheathing layer (30) which surrounds the insulating layers (22) of the two conductors (16), wherein the sheathing layer (30) is spaced apart from the insulating layers (22) and a second coolant channel (32) is formed between the sheathing layer (30) and the insulating layers (22), wherein by connecting the two of the first coolant channels (24), which form a coolant supply, and the second coolant channel (32), which forms a coolant return, at one axial end, a circulating cooling system for the electrically conductive conductors (16) is realized, which can be supplied with cooling medium from the charging station (14), wherein the electrical charging cable has a first pressure sensor (36) which is arranged in the second coolant channel (32) to detect a pressure drop in the coolant channel (32) and thus in the coolant return, wherein a second pressure sensor (38) is arranged in each of the two first coolant channels (24) in order to locate a leak in either the respective insulation layer (22) or in the jacket layer (30) by detecting a pressure difference between the first pressure sensor (36) and the respective second pressure sensor (38). [2] Electric charging cable according to claim 1, characterized by , that the two first coolant channels (24) between the respective insulation layers (22) and the respective conductors (16) are connected to each other at an axial end of the charging cable at an electrical connection (20) designed as a connector. [3] Electric charging cable according to claim 2, characterized by , that the two first coolant channels (24) are connected to each other at the electrical connection (20) designed as a connector in such a way that cooling medium can be pumped through the first and second coolant channels (24, 32). [4] Electric charging cable according to one of claims 1 to 3, characterized by, that the electrical charging cable has at least one axial end an electrical connection (18, 20) designed as a connector (18, 20) in order to electrically contact the electrically conductive conductors (16), wherein the connector (18, 20) connects the first coolant channels (24) to the second coolant channel (32). [5] Electric charging cable according to one of claims 1 to 4, characterized by , that the electrical charging cable has at least one axial end an electrical connection (18, 20) designed as a connector (18, 20) in order to electrically contact the electrically conductive conductors (16), wherein the connector (18, 20) is connectable to a coolant arrangement in order to supply the coolant fluid (28) to the first coolant channels (24).

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