Electric charging cable for a motor vehicle

Abstract

Electric charging cable for a motor vehicle (12), with at least one electrically conductive conductor (16) which is electrically contactable at its ends in order to transmit electrical energy, wherein the at least one electrically conductive conductor (16) is formed from a plurality of electrically conductive wires, with at least one insulating layer (22), wherein each electrically conductive conductor (16) is surrounded by one insulating layer (22), with at least one first coolant channel (24) in which a cooling fluid (28) can be guided for cooling one electrically conductive conductor (16) at a time, wherein the respective insulating layer (22) is spaced apart from the respective electrically conductive conductor (16) and the respective first coolant channel (24) is formed by a respective first cavity (26) between the respective insulating layer (22) and the respective electrically conductive conductor (16) such that the respective electrically conductive conductor (16) is not insulated from the cooling fluid (28), so that the cooling fluid (28) flows directly around the electrically conductive strands of the respective electrically conductive conductor (16), wherein the electric charging cable further comprises a sheathing layer (30) which circumferentially surrounds the at least one insulating layer (22), wherein the sheathing layer (30) is spaced apart from the at least one insulating layer (22) and a second coolant channel between the sheathing layer (30) and the at least one insulating layer (22) is formed by a second cavity (32) between the sheathing layer (30) and the at least one insulating layer (22), wherein the electrical charging cable has a connector (20) at an axial end to electrically contact the respective electrically conductive conductor (16), wherein the connector (20) connects the at least one first coolant channel (24), which forms a coolant supply, with the second coolant channel, which forms a coolant return, such that a supply tap (34) is arranged in the connector (20) which is connected to the respective first coolant channel (24) to guide the cooling medium (28) out of the respective first coolant channel (24) and into the second coolant channel between the at least one insulating layer (22) and the sheathing layer (30).

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] DE 23 22 085 A and US 2010 / 0 277 127 A1 reveal further state of the art.

[0008] 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 with minimal technical effort.

[0009] This problem is solved by an electric charging cable for a motor vehicle according to claim 1.

[0010] The respective insulating layer is spaced away from the respective electrically conductive conductor, and the respective first coolant channel between the respective insulating layer and the at least one electrically conductive conductor is formed by a cavity between the respective insulating layer and the respective electrically conductive conductor in such a way that the respective electrically conductive conductor is not insulated from the cooling fluid and that the cooling fluid flows directly around the at least one electrically conductive conductor.

[0011] The electric charging cable further comprises a sheathing layer that completely surrounds the respective insulation layer, wherein the sheathing layer is spaced apart from the respective insulation layer, and wherein a second coolant channel is formed between the sheathing layer and the respective insulation layer.

[0012] The electrical charging cable has a connector at one axial end to electrically contact the at least one electrically conductive conductor, wherein the connector connects the at least one first coolant channel, which forms a coolant supply, with the second coolant channel, which forms a coolant return, such that a supply tap is arranged in the connector which is connected to the respective first coolant channel in order to carry the cooling medium out of the respective first coolant channel and introduce it into the second coolant channel between the insulation layer and the jacket layer.

[0013] In accordance with the present invention, the at least one electrically conductive conductor is not separately insulated, so that the cooling fluid in the at least one first cooling channel can directly flow around the at least one electrical conductor or electrical conductors of the at least one electrical conductor or directly touch the current-carrying conductors of the at least one electrical conductor, so that direct heat transfer from the at least one electrical conductor to the cooling fluid is possible.

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

[0015] The electric charging cable further comprises a sheathing layer that completely surrounds the respective insulating layer, with the sheathing layer being spaced apart from the respective insulating layer and the second coolant channel being formed between the sheathing layer and the respective insulating layer. This allows the cooling fluid to be guided in a closed system throughout the entire charging cable, thus enabling defined cooling of the at least one electrically conductive conductor.

[0016] The electrical charging cable has a connector at one axial end to electrically contact at least one electrically conductive conductor, with the connector connecting the respective first coolant channel to the second coolant channel. This allows the respective first coolant channel to be connected to the second coolant channel, enabling a defined coolant circulation with minimal technical effort.

[0017] The electric charging cable can therefore be provided with improved heat dissipation and with minimal technical effort, thus fully solving the problem of the present invention.

[0018] According to claim 1, a cavity is formed between the respective insulating layer and the at least one electrically conductive conductor, forming the at least one first coolant channel. Because the at least one first coolant channel is formed solely by a cavity between the respective insulating layer and the respective electrical conductor, and no separate coolant channel is required, the technical complexity for the at least one first coolant channel and for the electric charging cable as a whole can be significantly reduced.

[0019] According to claim 1, the at least one first coolant channel forms a coolant supply and the second coolant channel a coolant return. This allows the cooling fluid to be supplied to the electrically conductive conductor under cooled conditions and returned via the second coolant channel, thus achieving a defined coolant circulation.

[0020] In a preferred embodiment, the electric charging cable has a connector at at least one axial end to electrically contact the respective conductor, wherein the connector has an opening that is connected to the respective coolant channel to drain the coolant from the electric charging cable. This allows a coolant flow to be generated in the coolant channel and the coolant to be drained from the respective coolant channel with minimal technical effort.

[0021] In a preferred embodiment, the cooling fluid is formed from ambient air, which is introduced into the respective coolant channel either cooled or uncooled. This allows cooling fluid to be supplied to at least one conductor with minimal technical effort.

[0022] In a particular embodiment, the electrical charging cable has a pressure sensor located in the second coolant channel to detect a pressure drop within that channel. This allows for the detection of leaks in the coolant channel with minimal technical effort, enabling early detection of any cooling system malfunctions.

[0023] In a preferred embodiment, a second pressure sensor is arranged in the respective first coolant channel to determine the location of any damage to the coolant channel. This allows a leakage location in the coolant channel to be detected and determined with minimal technical effort, thereby enabling leak localization and corresponding repair with minimal technical effort.

[0024] Overall, the present electric charging cable allows for improved cooling of the electrical conductors with minimal technical effort, as the cooling fluid flows directly around the respective electrical conductor and the heat flow is not hindered by insulation, while at the same time the technical effort is significantly reduced by the spacing of the respective insulation layer from the respective electrical conductor and by the respective first cooling channel formed between them, which forms a coolant line.

[0025] 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 with two coolant channels; and Fig. 4 a schematic view of a longitudinal section of the electric charging cable according to the embodiment from Fig. 3.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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 returned to the charging station 14 at the connector 20 via a second coolant channel not shown here, as explained in more detail below.

[0031] In Fig. Figure 2 shows a schematic sectional view of an electrical conductor arrangement 10 that does not conform to the invention.

[0032] 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.

[0033] The cooling medium 28 can be formed from cooled or uncooled ambient air or be designed as a circulating cooling liquid.

[0034] In Fig. Figure 3 shows a cross-sectional representation of an embodiment of the 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.

[0035] 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.

[0036] In this arrangement, the first cavities 26 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.

[0037] 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.

[0038] 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.

[0039] 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.

[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] In a preferred embodiment, a pressure sensor is arranged in each of the cavity 26 and the cavity 32 to measure pressure in the cooling system and to detect a leak in the insulation layer 22 or the jacket layer 30. If a pressure difference between the pressure sensors 36, 38 is detected, a leak in the insulation layer 22 or the jacket layer 30 can be identified and located.

Claims

[1] Electric charging cable for a motor vehicle (12), with at least one electrically conductive conductor (16) which is electrically contactable at its ends in order to transmit electrical energy, wherein the at least one electrically conductive conductor (16) is formed from a plurality of electrically conductive wires, with at least one insulating layer (22), wherein each electrically conductive conductor (16) is surrounded by one insulating layer (22), with at least one first coolant channel (24) in which a cooling fluid (28) can be guided for cooling one electrically conductive conductor (16) at a time, wherein the respective insulating layer (22) is spaced apart from the respective electrically conductive conductor (16) and the respective first coolant channel (24) is formed by a respective first cavity (26) between the respective insulating layer (22) and the respective electrically conductive conductor (16) such that the respective electrically conductive conductor (16) is not insulated from the cooling fluid (28), so that the cooling fluid (28) flows directly around the electrically conductive strands of the respective electrically conductive conductor (16), wherein the electric charging cable further comprises a sheathing layer (30) which circumferentially surrounds the at least one insulating layer (22), wherein the sheathing layer (30) is spaced apart from the at least one insulating layer (22) and a second coolant channel between the sheathing layer (30) and the at least one insulating layer (22) is formed by a second cavity (32) between the sheathing layer (30) and the at least one insulating layer (22), wherein the electrical charging cable has a connector (20) at an axial end to electrically contact the respective electrically conductive conductor (16), wherein the connector (20) connects the at least one first coolant channel (24), which forms a coolant supply, with the second coolant channel, which forms a coolant return, such that a supply tap (34) is arranged in the connector (20) which is connected to the respective first coolant channel (24) to guide the cooling medium (28) out of the respective first coolant channel (24) and into the second coolant channel between the at least one insulating layer (22) and the sheathing layer (30). [2] Electric charging cable according to claim 1, characterized by , that the electrical charging cable has a pressure sensor (38) which is arranged in the second coolant channel to detect a pressure drop in the second coolant channel. [3] Electric charging cable according to claim 2, characterized by , that a second pressure sensor (36) is arranged in the at least one first coolant channel (24) to determine the position of any damage to the respective first coolant channel (24). [4] Electric charging cable according to one of claims 1 to 3, characterized by , that the connector (20) serves to connect the charging cable to the motor vehicle (12).

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