Charging connectors for electric and hybrid vehicles

Abstract

The present invention relates to a charging connector for a hybrid vehicle (2), which includes a housing (3) and charging contacts (4), which are disposed within the housing (3) and contact corresponding charging contacts (14) of a corresponding charging connector (1). The present invention proposes providing a fluid container (6), which is filled with a fluid (5) and is in thermally conductive contact with at least one charging contact (4), thereby improving heat dissipation from a charging station (25) to a charging connector (1) that is not equipped with a cooling system.

Description

[Technical Field]

[0001] The present invention relates to a charging connector for electric and hybrid vehicles having a housing and charging contacts disposed within the housing and in contact with corresponding charging contacts of a corresponding charging connector, and to the use of such a charging connector.

[0002]

[0002] Electric and hybrid vehicles typically have a rechargeable energy storage device, typically a high-voltage battery, that provides energy to the electric drive motor during operation. Because these high-voltage batteries have a limited storage capacity, they must be periodically recharged at a charging station. The battery is charged via a charging cable installed between the charging station and the vehicle. This charging cable has, on one end, a charging plug that can be inserted into a charging socket installed in the charging station, and on the other end, a charging coupling that can be connected to a charging plug built into the electric or hybrid vehicle (e.g., compliant with European Standard IEC 62196 Type 2). In this specification, charging sockets, charging plugs, charging couplings, and built-in charging plugs are collectively referred to as "charging connectors." Charging sockets and charging couplings have contact sleeves as charging contacts, and charging plugs and built-in charging plugs that can be built into electric or hybrid vehicles have contact pins as charging contacts that can be inserted into the contact sleeves.

[0003]

[0003] For example, as described in EP 3 043 421 A1, charging current flowing through a charging connector generates heat due to resistive current heat loss. However, heating of the charging connector is limited to a threshold temperature rise. For example, the IEC 62196-3 standard limits the temperature rise to an upper limit of 50 K. Therefore, with a standardized connector geometry, the maximum charging current during continuous load operation generally cannot exceed 200 A. However, when charging the battery of an electric or hybrid vehicle intermittently, a higher charging current is required to charge the battery in the desired short time. This may temporarily cause the temperature rise of the charging connector to exceed the upper limit. The cable cross-sectional area of ​​the electrical connection body cannot be arbitrarily large due to the standardized geometry of the plug connector and the need to minimize the amount of conductive material (usually copper) used in the electrical connection body.

[0004]

[0004] In this regard, according to EP 3 043 421 A1, the object to be achieved is to provide an electrical connection body which allows high charging currents while limiting heating, thus improving short-term current carrying capacity. This object is achieved by providing an electrical connection body for a charging plug or socket, which has a first connection area for electrical connection to an electrical energy receptor and a second connection area for galvanic connection to an electrical energy supply source, and which is designed with cooling fluid channels formed in the electrical connection body, and which cooling fluid channels of the electrical connection body are fluidly connected to a cooling fluid source arranged in a charging station.

[0005]

[0005] It is well known that cooling of charging connectors for electric and hybrid vehicles occurs from the charging station side. DE 10 2015 119 338 A1 describes a charging plug's contact sleeve element provided with two connection points for a coolant line. A spiral plug-on element guides the coolant circularly around the contact sleeve element. The two connection points serve as the coolant inlet and outlet, and the coolant is delivered from the charging station to the charging plug. EP 3 433 902 B1 also discloses a plug connector part with cooled contact elements. Here, too, the charging station supplies coolant to the contact elements of a charging coupling connected to a charging cable via a coolant line. A fluid is provided as the coolant, guided perpendicular to the contact elements, and flows back through the hollowed-out contact elements.

[0006]

[0006] Furthermore, 10 2016 105 361 B4 also discloses a plug connector part having cooled contact elements, and here too, it is disclosed that a coolant is supplied to the contact elements of a charging socket connected to a charging cable on the charging station side via a coolant line. Guide elements are arranged on the contact elements, ensuring that the coolant as compressed air flows around the contact elements.

[0007]

[0007] Based on this, it is an object of the present invention to improve heat dissipation in a charging connector that is not equipped with a cooling system from a charging station.

[0008]

[0008] The object of the invention is achieved by the subject matter of the independent claims. Preferred developments of the invention are set out in the dependent claims.

[0009]

[0009] According to the present invention, a charging connector for electric vehicles and hybrid vehicles is provided, which has a housing, charging contacts disposed within the housing and in contact with corresponding charging contacts of a corresponding charging connector, and a fluid container filled with fluid and in thermally conductive contact with at least one of the charging contacts.

[0010] An important aspect of the present invention is that the energy generated at the charging contacts during charging is absorbed by the fluid, thereby avoiding overheating of the charging contacts and charging connector.

[0011] In principle, various fluids can be used in the present invention. However, preferably, the fluid is a liquid, such as water or a mixture of water with other substances, in particular a glycol-water mixture. Glycol is often used as a coolant, antifreeze, or deicer, and its melting point is lower than that of water, at -10 to -15°C. When combined with water, i.e., the glycol-water mixture referred to herein, the melting point is even lower, reaching -55°C depending on the mixture ratio. Thus, the fluid remains liquid even at very low temperatures, allowing the present invention to be widely used in extremely cold climates. Alternatively, in a preferred development, the fluid may be an oil, preferably a mineral oil, vegetable oil, silicone oil, or synthetic oil.

[0012]

[0012] The fluid container can be thermally coupled to the charging contacts in various ways. However, according to a preferred embodiment of the invention, the fluid container is connected to at least one charging contact via a heat pipe. A heat pipe is a heat exchanger that utilizes the enthalpy of vaporization of the medium and allows a high heat flux density. In this way, a large amount of heat can be transferred over a small cross-sectional area.

[0013]

[0013] The heat pipe can be connected to the charging contact in various ways. However, according to a preferred development of the invention, the heat pipe is inserted transversely to the longitudinal direction of the charging contact. Furthermore, according to a preferred development of the invention, the charging contact is pin-shaped and the heat pipe continues within the charging contact along the longitudinal direction of the charging contact. This lengthens the contact path between the charging contact and the heat pipe, further improving heat transfer.

[0014] According to another embodiment of the invention that does not use a heat pipe, the fluid container has a wall with two openings through which at least one charging contact passes, so that the charging contact within the fluid container is in contact with the fluid, allowing for effective heat transfer from the charging contact to the fluid.

[0015]

[0015] In general, it is also possible for the charging contacts to be in direct contact with the fluid. However, according to a preferred development of the invention, the charging contacts, at least in the region within the fluid container, have a galvanically insulating coating, for example made of an electrically insulating and highly thermally conductive plastic. In this way, the charging contacts are electrically insulated from the fluid, which is advantageous from a safety point of view and does not significantly affect the heat transfer from the charging contacts to the fluid.

[0016]

[0016] To reliably prevent leakage of the fluid container, according to a preferred development of the present invention, the fluid container is placed in a housing of the charging connector, and the cavity between the inner wall of the housing and the fluid container is at least partially, preferably completely, potted with a potting compound. In this way, sealing of the fluid container is not achieved only by sealing the opening of the fluid container. Rather, if the fluid container is completely embedded in the potting compound, it is possible to seal the fluid container as a whole, i.e., along its entire surface. A casting resin is particularly suitable as the potting compound. A casting resin is a synthetic resin that is processed into a final product in liquid form and then solidifies. The liquid resin is injected into the housing, in which other components, such as the charging contacts and the fluid container, are already located. Finally, a casting resin body with a free-form surface is created, which safely and hermetically surrounds the other components of the charging connector within the housing.

[0017]

[0017] Finally, according to a preferred embodiment of the present invention, the volume of the fluid is between 150 and 20 mL, preferably between 60 and 20 mL, and particularly preferably between 40 and 20 mL. Within the scope of the present invention, it has been found that even such small amounts of fluid (for example, when using a mixture of water and glycol as the fluid) are sufficient to effectively dissipate the heat generated at the charging contacts during high-power charging.

[0018]

[0018] In addition, the above-mentioned object can also be achieved by using the above-mentioned charging connector on the vehicle body of an electric vehicle or hybrid vehicle. The charging connector is preferably a charging plug conforming to the IEC 62196 standard. [Brief explanation of the drawings]

[0019] The invention will now be described in detail with reference to the drawings, which are merely illustrative examples. [Figure 1] FIG. 1 is a perspective view of a charging connector according to a preferred exemplary embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of a charging connector corresponding to the charging connector of FIG. [Figure 3] FIG. 3 schematically illustrates a first exemplary embodiment of the present invention in which the charging contacts of the charging connector are cooled by a fluid provided in a fluid container. [Figure 4] FIG. 4 schematically illustrates a first exemplary embodiment of the present invention in which the charging contacts of the charging connector are cooled by a fluid provided in a fluid container. [Figure 5] FIG. 5 schematically illustrates a first exemplary embodiment of the present invention in which the charging contacts of the charging connector are cooled by a fluid provided in a fluid container. [Figure 6] FIG. 6 shows a schematic diagram of an electric or hybrid vehicle equipped with a charging connector according to a preferred exemplary embodiment of the present invention.

[0020] Detailed Description of the Invention

[0021]

[0021] Fig. 1 shows a perspective view of a charging connector 1 according to a preferred exemplary embodiment of the present invention. This is a charging plug for installation in a vehicle body 12 of an electric or hybrid vehicle 2, as shown schematically in Fig. 6. The charging connector 1 is a charging plug that substantially and in terms of its mating surface complies with European standard IEC 62196 Type 2. In addition to AC charging contacts 13, protection contacts 14, and communication contacts 15 for AC charging, it has two DC charging contacts 4 for DC charging.

[0022]

[0022] The charging connector 1 is composed of a first housing portion 16 and a second housing portion 17, which together form the housing 3 of the charging connector 1. The first housing portion 16 is connected to the second housing portion 17 by laser welding. The first housing portion 16 faces outward when installed in the vehicle body 12 of the electric vehicle or hybrid vehicle 2, and is intended to receive a corresponding charging connector 18 designed as a charging coupling, as shown in Figure 6.

[0023]

[0023] Such a corresponding charging connector 18 is shown in a perspective view in Figure 2. This is a charging coupling for DC charging, and its connector surface complies with European standard IEC 62196 Type 2. For DC charging, two corresponding charging contacts 19 are provided, which interact with the DC charging contacts 4 of the charging connector 1 during charging. In addition, the corresponding charging connector 19 has two communication contacts 22 and a protection contact 21. Specifically, in this case, the DC charging contacts 22 of the charging connector 1 are designed as contact pins, and the corresponding DC charging contacts 19 of the corresponding charging connector 18 are designed as contact sleeves, into which the contact pins can be inserted.

[0024]

[0024] It is therefore essential that the charging connector 1 is equipped with a fluid container 6, which is filled with a fluid 5 and which is in heat-conducting contact with the two DC charging contacts 4. Various designs are possible, as shown diagrammatically in Figures 3, 4 and 5.

[0025] 3 shows a first exemplary embodiment of the present invention for cooling the DC charging contacts 4 of the charging connector 1 with a fluid 5 provided in a fluid container 6. The fluid 5, in this case a glycol-water mixture with a volume of 40 mL, is filled into the fluid container 6 through an opening 27, which is now closed with a closure 28.

[0026] 3, the fluid container 6 is not directly coupled to the DC charging contact 4. Rather, a heat pipe 7 is disposed between the DC charging contact 4 and the fluid container 6 to ensure effective heat transfer from the DC charging contact 4 to the fluid 5 provided in the fluid container 6.

[0027]

[0027] The heat pipe 7 is introduced into the fluid container 6 through an opening 20 sealed with a seal 26, so that the heat pipe 7 protrudes above the surface of the fluid 5 in the fluid container 6. This lengthens the contact path between the heat pipe 7 and the fluid 5, allowing for effective heat transfer from the heat pipe 7 to the fluid 5.

[0028]

[0028] The contact between the heat pipe 7 and the DC charging contact 4 is shown very diagrammatically here. In particular, the heat pipe 7 can be inserted transversely to the longitudinal direction of the DC charging contact 4. Alternatively or additionally, the heat pipe 7 can continue into the DC charging contact 4 along the longitudinal direction of the DC charging contact 4. In the latter case, a relatively long path for the heat pipe 7 within the DC charging contact 4 is possible, further improving the thermal coupling between the heat pipe 7 and the DC charging contact 4.

[0029] 4 is a schematic diagram of a second exemplary embodiment of the present invention in which the DC charging contacts 4 of a charging connector 1 are cooled by a fluid 5 provided in a fluid container 6. The main difference from the first embodiment of the present invention is that the fluid 5 is not coupled to the DC charging contacts 4 by a heat pipe 7. Rather, the fluid container 6 is provided with a wall 8 having two openings 9 through which the DC charging contacts 4 pass. Each opening 9 is sealed with a seal 26.

[0030] For safety reasons, the DC charging contact 4 has a galvanically insulating coating 10 in the region of the fluid container 6 to achieve electrical insulation from the fluid 5. For this galvanically insulating coating, an electrically insulating yet thermally conductive plastic is selected so that the thermal coupling of the heat pipe 7 to the fluid 5 is not substantially impaired.

[0031]

[0031] Figure 5 shows a development of the second exemplary embodiment of the present invention as a third preferred exemplary embodiment, in which a fluid container 6 is formed in the housing 3 of the charging connector, and the cavity between the inner wall of the housing 3 and the fluid container 6 is potted with a potting compound 11 to prevent leakage in the area of ​​the opening 9 of the fluid container 6. In this case, a casting resin is used as the potting compound, i.e., a molding resin that is processed into the final product in liquid form and then hardens. The liquid resin is injected into the housing, in which other components such as the charging contacts 4 and the fluid container 6 are already located. As a result, a casting resin body with a free-form surface is formed, which safely and hermetically surrounds the other components of the charging connector 1 in the housing 3.

[0032] As mentioned above, in this case the charging connector 1 is used in the form of a built-in plug in the vehicle body 12 of the electric or hybrid vehicle 2. In this regard, reference is made to Figure 6, which shows a schematic diagram of a system according to a preferred exemplary embodiment of the invention, comprising the charging connector 1 installed in the vehicle body 12 of the electric or hybrid vehicle 2, a corresponding charging connector 18 in the form of a charging coupling, a charging station 25, and a charging cable 24 connected to the charging station 20 and carrying the charging coupling 23. [Explanation of symbols]

[0033] 1...Charging connector, 2...electric and hybrid vehicles, 3...Housing, 4...Charging contact / DC charging contact, 5...Fluid, 6...fluid container, 7...heat pipe, 8...wall, 9...opening, 10...coating, 11...potting compound, 12...Vehicle body, 13...AC charging contact, 14...protective contact, 15...Communication contacts, 16...first housing part, 17...second housing part, 18...Compatible charging connector, 19...corresponding charging contacts, 20...opening, 21...corresponding protective contact, 22...corresponding communication contact, 23...Charging coupling, 24...Charging cable, 25…charging stations, 26...Seal, 27...opening, 28...Occluded part, 29...wall.

Claims

1. A charging connector (1) for electric vehicles and hybrid vehicles (2), a housing (3); Charging contacts (4) arranged in the housing (3) and in contact with corresponding charging contacts (14) of a corresponding charging connector (1); a fluid container (6) filled with a fluid (5) and in thermally conductive contact with at least one charging contact (4); A charging connector having a

2. 2. The charging connector according to claim 1, wherein the fluid (5) is a liquid.

3. 3. The charging connector according to claim 2, wherein the liquid is water or a mixture of water with another substance or oil.

4. 4. The charging connector according to any one of claims 1 to 3, wherein the fluid container (6) is connected to at least one of the charging contacts (4) via a heat pipe (7).

5. 5. The charging connector according to claim 4, wherein the heat pipe (7) is inserted transversely to the longitudinal direction of the charging contact (4).

6. 6. A charging connector according to claim 4 or 5, wherein the charging contact (4) is pin-shaped and the heat pipe (7) continues within the charging contact (4) along the longitudinal direction of the charging contact (4).

7. 4. The charging connector according to claim 1, wherein the fluid container (6) has a wall (8) with two openings (9), the openings (9) allowing at least one of the charging contacts (4) to pass through.

8. 8. The charging connector according to claim 7, wherein the charging contacts have a galvanically insulating coating (10) at least in the region within the fluid container (6).

9. The charging connector according to any one of claims 1 to 8, wherein the fluid container (6) is formed within the housing, and the cavity between the inner wall of the housing (3) and the fluid container (6) is at least partially potted with a potting compound (11).

10. The charging connector according to any one of claims 1 to 9, wherein the volume of the fluid is 150 to 20 mL.

11. Use of the charging connector according to any one of claims 1 to 10 on a vehicle body of an electric vehicle or a hybrid vehicle.

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