Charging connector for electric and hybrid vehicles

Abstract

The invention relates to a charging connector for electric and hybrid vehicles (2), having a housing (3) and charging contacts (4), which are arranged in the housing (3), for contacting corresponding charging contacts (14) of a corresponding charging connector (1). The invention proposes providing a fluid container (6) which is filled with a fluid (5) and is in thermally conductive contact with at least one of the charging contacts (4). In this way, heat dissipation is improved for a charging connector (1) that is not itself equipped with a cooling system from a charging station (25).

Description

[0001] P22230WO 1 November 9, 2023 Kiekert AG Charging connector for electric and hybrid vehicles The present invention relates to a charging connector for electric and hybrid vehicles, with a housing and charging contacts arranged in the housing for contacting corresponding charging contacts of a corresponding charging connector, as well as a use of such a charging connector. Electric and hybrid vehicles have a rechargeable energy storage device, usually a high-voltage battery, which provides energy to an electric drive motor during driving. The storage capacities of these high-voltage batteries are limited, so they must be recharged regularly at a charging station. The battery is charged via a charging cable provided between the charging station and the vehicle, wherein the charging cable can, for example,According to European standard IEC 62196 Type 2, on one side it has a charging plug that can be plugged into a charging socket provided at the charging station, and on the other side it has a charging coupling that can be connected to a charging plug installed in the electric or hybrid vehicle. In this case, charging sockets, charging plugs, charging couplings, and charging plugs are subsumed under the term "charging connector." Charging sockets and charging couplings have contact sleeves as charging contacts, and charging plugs, as well as charging plugs that can be installed in electric and hybrid vehicles, have contact pins as charging contacts that can be inserted into the contact sleeves. P22230WO 2 November 9, 2023 Kiekert AG As explained, for example, in EP 3 043 421 A1, a charging current flowing through the charging connector causes it to heat up due to ohmic current heat losses.However, the heating of the charging connector is limited to a limit temperature increase. For example, according to the IEC 62196-3 standard, the limit temperature increase is limited to 50 K. This, in turn, leads to a maximum charging current that generally cannot exceed 200 A in continuous load operation with largely standardized connector geometries. However, with intermittent charging of the battery of an electric or hybrid vehicle, higher charging currents are necessary over limited periods in order to charge the battery in the desired short time. This can lead to temporary heating of the charging connectors that exceeds the limit temperature increase. The cable cross-section of the electrical connector bodies cannot be increased indefinitely because the connector geometries are standardized and, in addition, the electrical connector bodies should use the smallest possible amount of conductive material, usually copper.In this respect, according to EP 3 043 421 A1, the object is to be achieved by providing an electrical connection body that enables increased charging currents with limited heating and therefore has an increased short-term current-carrying capacity. This object is to be achieved by providing an electrical connection body for a charging plug or a charging socket, wherein the electrical connection body has a first connection area for galvanic connection to an electrical energy receiver and a second connection area for galvanic connection to an electrical energy source, wherein the electrical connection body is designed such that it has a cooling fluid channel formed in the electrical connection body, wherein the cooling fluid channel of the electrical connection body is fluidly connected to a cooling fluid source arranged in a charging station.Cooling of a charging connector for electric and hybrid vehicles, which originates from the side of the charging station, is also well known from the prior art. For example, DE 102015 119 338 A1 describes two connection points for coolant lines arranged on a contact sleeve element of a charging plug. By means of a spiral-shaped plug-in element, coolant is guided in a circle around the contact sleeve element. The two connection points serve as inlets and outlets for the coolant, which is guided from the charging station to the charging plug. EP 3433 902 B1 also describes a connector part with cooled contact elements. Here, too, the supply of coolant via coolant lines to the contact elements of the charging coupling connected to the charging cable is provided on the charging station side.A fluid is provided as the coolant, which is directed perpendicular to the contact element into the hollowed-out contact element and flows back within the contact element. P22230WO 4 November 9, 2023 Kiekert AG Finally, 10 2016 105 361 B4 also describes a connector part with a cooled contact element, wherein, on the charging station side, a coolant is also provided via coolant lines to the contact elements of a charging socket connected to the charging cable. Guide elements are arranged on the contact elements, which are intended to ensure that the coolant in the form of compressed air flows around the contact elements. Based on this, the object of the present invention is to achieve improved heat dissipation in a charging connector that is not itself equipped with a cooling system on the part of a charging station. This object is achieved by the subject matter of the independent claims.Preferred developments of the invention are described in the subclaims. According to the invention, a charging connector for electric and hybrid vehicles is thus provided, comprising a housing, charging contacts arranged in the housing for contacting corresponding charging contacts of a corresponding charging connector, and a fluid container filled with a fluid, which is in thermally conductive contact with at least one of the charging contacts. An essential aspect of the invention is therefore that the energy generated at a charging contact during charging is absorbed by the fluid, so that overheating of the charging contact and the charging connector can be avoided. In principle, various fluids can be used for the invention. However, the fluid is preferably a liquid, e.g., water or a mixture of water and another substance, very particularly preferably a glycol-water mixture.Glycols are frequently used in coolants, antifreeze, and de-icers because their melting point is -10 to -15 °C, lower than that of water. In combination with water, i.e., in the glycol-water mixture discussed here, the melting point is even significantly lower and can reach -55 °C depending on the mixing ratio. In this way, the fluid remains liquid even at very low temperatures, which enables the invention to be widely used even in very cold climates. Alternatively, according to a preferred development, the fluid is an oil, preferably a mineral oil, a vegetable oil, a silicone oil, or a synthetic oil. The fluid container can be thermally coupled to the charging contact in various ways. According to a preferred development of the invention, however, the fluid container is connected to at least one of the charging contacts by means of a heat pipe.A heat pipe is a heat exchanger that utilizes the evaporation enthalpy of a medium to achieve a high heat flux density. In this way, large amounts of heat can be transferred over a small cross-sectional area. The heat pipe can be connected to the charging contact in different ways. According to a preferred development of the invention, however, the heat pipe is inserted into the charging contact 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 runs within the charging contact in its longitudinal direction. This allows a long contact path between the charging contact and the heat pipe, which further improves heat transfer between the charging contact and the heat pipe.According to an alternative embodiment of the invention without a heat pipe, the fluid container has a wall with two openings through which at least one of the charging contacts is passed. In this way, the charging contact comes into contact with the fluid inside the fluid container, which also enables effective heat transfer from the charging contact to the fluid. In principle, it is possible for the charging contact to come into direct contact with the fluid. According to a preferred development of the invention, however, it is provided that the charging contact has a galvanically insulating coating, e.g. made of an electrically insulating but highly thermally conductive plastic, at least in its area inside the fluid container.In this way, the charging contact is electrically insulated from the fluid, which is advantageous from a safety perspective, without the heat transfer from the charging contact to the fluid being significantly affected. To reliably prevent leaks at the fluid container, according to a preferred development of the invention, the fluid container is arranged within the housing of the charging connector, wherein the cavity between the inner wall of the housing and the fluid container is at least partially, preferably completely, filled with a potting compound. In this way, sealing of the fluid container is achieved not only by seals at the openings of the fluid container. Rather, sealing of the fluid container as a whole is possible, i.e. along its entire surface, if this is completely embedded in the potting compound. Cast resin has proven to be a particularly suitable potting compound.A casting resin is a synthetic resin that is processed in liquid form into the final product and solidifies as this or its component. The still-liquid resin is poured into the housing in which the other components of the charging connector, such as the charging contacts and the fluid container, are already arranged. This ultimately creates a casting resin body with freeform surfaces that securely and sealingly encloses the other components of the charging connector in its housing. P22230WO 8 November 9, 2023 Kiekert AG Finally, according to a preferred embodiment of the invention, the volume of the fluid is between 150 and 20 ml, preferably between 60 and 20 ml, most preferably between 40 and 20 ml.Within the scope of the invention, it has been found that even such small quantities of a fluid can be sufficient to effectively dissipate the heat generated during a high-performance charging process for an electric vehicle from the charging contact, e.g. when a mixture of water and glycol is used as the fluid. Furthermore, the object mentioned above is also achieved by using a previously described charging connector on the vehicle body of an electric or hybrid vehicle. The charging connector is very particularly preferably a built-in charging connector in accordance with the IEC 62196 standard. The invention is explained in more detail below with reference to drawings which merely represent exemplary embodiments. In the drawings, Fig. 1 shows a perspective view of a charging connector according to a preferred exemplary embodiment of the invention, Fig. 2 shows a perspective view of a charging connector which is comparable to the charging connector from Fig.1 corresponding charging connector, P22230WO 9 November 9, 2023 Kiekert AG Fig. 3 schematically shows a first exemplary embodiment of the invention for cooling a charging contact of a charging connector by means of a fluid provided in a fluid container, Fig. 4 schematically shows a first exemplary embodiment of the invention for cooling a charging contact of a charging connector by means of a fluid provided in a fluid container, Fig. 5 schematically shows a first exemplary embodiment of the invention for cooling a charging contact of a charging connector by means of a fluid provided in a fluid container, Fig. 6 schematically shows an electric or hybrid vehicle with a charging connector according to a preferred exemplary embodiment of the invention. Fig. 1 shows a perspective view of a charging connector 1 according to a preferred exemplary embodiment of the invention.This is a charging plug for installation in the vehicle body 12 of an electric or hybrid vehicle 2, as shown schematically in Fig. 6. The present charging connector 1 is essentially, and in terms of its mating face, a charging plug according to the European standard IEC 62196 Type 2. In addition to AC charging contacts 13 for AC charging, a protective contact 14 P22230WO 10 November 9, 2023 Kiekert AG and communication contacts 15, the charging connector 1 has two DC charging contacts 4 for DC charging. The charging connector 1 is composed of a first housing part 16 and a second housing part 17, which together form the housing 3 of the charging connector 1. The first housing part 16 is connected to the second housing part 17 by laser welding.The first housing part 16 corresponds to the housing part that faces outward when installed in the vehicle body 12 of an electric or hybrid vehicle 2 and, as indicated in Fig. 6, is intended to receive a corresponding charging connector 18 designed as a charging coupling. Such a corresponding charging connector 18 is shown in a perspective view in Fig. 2. This is a charging coupling for direct current charging, the mating face of which complies with the European standard IEC 62196 Type 2. Two corresponding charging contacts 19 are provided for direct current charging, which interact with the direct current charging contacts 4 of the charging connector 1 during charging. In addition, the corresponding charging connector 19 has two communication contacts 22 and a protective contact 21.Specifically, 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. It is essential that the charging connector 1 is equipped with a fluid container 6 filled with a fluid 5, which is in heat-conducting contact with the two DC charging contacts 4. Various configurations are possible for this purpose, as shown schematically in Figs. 3, 4, and 5, for example. Fig. 3 schematically shows a first exemplary embodiment of the invention for cooling the DC charging contacts 4 of a charging connector 1 by means of a fluid 5 provided in a fluid container 6.The fluid 5 is presently a glycol-water mixture with a volume of 40 ml, which has been poured into the fluid container 6 via an opening 27, now closed with a closure 28. As can be seen from Fig. 3, the fluid container 6 is not directly coupled to the direct current charging contact 4 shown there. Rather, a heat pipe 7 is arranged between the direct current charging contact 4 and the fluid container 6, which ensures effective heat transfer from the direct current charging contact 4 to the fluid 5 provided in the fluid container 6. The heat pipe is guided into the interior of the fluid container 6 via an opening 20 sealed by a seal 26, in such a way that the heat pipe 7 P22230WO 12 November 9, 2023 Kiekert AG projects beyond the filling level of the fluid 5 in the fluid container 6.In this way, a long contact path between the heat pipe 7 and the fluid 5 is ensured, which enables effective heat transfer from the heat pipe 7 to the fluid 5. The contact of the heat pipe 7 with the DC charging contact 4 is shown here only very schematically. Specifically, the heat pipe 7 can be inserted into the charging contact 4 transversely to the longitudinal direction of the latter. Alternatively or additionally, it is also possible for the heat pipe 7 to run in the longitudinal direction of the charging contact 4. The latter enables a relatively long path for the heat pipe 7 within the charging contact 4, which further improves the thermal coupling of the heat pipe 7 to the charging contact 4. Fig. 4 now schematically shows a second exemplary embodiment of the invention for cooling the DC charging contacts 4 of a charging connector 1 by means of a fluid 5 provided in a fluid container 6.The essential difference from the first preferred embodiment of the invention is that the coupling of the fluid 5 to the direct current charging contact 4 is not achieved with a heat pipe 7. Rather, the fluid container 6 is provided with a wall 8 having two openings 9 through which a respective direct current charging contact 4 is passed. The sealing of the openings 9 is achieved by a seal 26 each. P22230WO 13 November 9, 2023 Kiekert AG For safety reasons, the direct current charging contact 4 has a galvanically insulating coating 10 in its area within the fluid container 6 in order to achieve electrical insulation from the fluid 5. An electrically insulating plastic was selected for this galvanically insulating coating, which, however, has good thermal conductivity, so that the thermal coupling of the heat pipe 7 to the fluid 5 is practically unaffected. Fig.Figure 5 shows, as a third preferred embodiment of the invention, a further development of the second embodiment of the invention, in which the fluid container 6 is formed within the housing 3 of the charging connector, and the cavity between the inner wall of the housing 3 and the fluid container 6 is filled with a potting compound 11 in such a way that possible leaks in the area of ​​the openings 9 of the fluid container 6 are avoided. In this case, a casting resin is used as the potting compound, i.e., a synthetic resin that is processed in liquid form to form the final product and solidifies as this or as a component thereof. For this purpose, the still-liquid resin was poured into the housing in which the other components of the charging connector 1, such as the charging contacts 4 and the fluid container 6, were already arranged.This results in a cast resin body with free-form surfaces that securely and sealingly encloses the other components of the charging connector 1 in its housing 3. P22230WO 14 November 9, 2023 Kiekert AG As already mentioned above, the charging connector 1 is used in the present case in the form of a built-in plug on the vehicle body 12 of an electric or hybrid vehicle 2. In this context, reference may be made to Fig. 6, which schematically shows a system according to a preferred exemplary embodiment of the invention, comprising a charging connector 1 installed in a vehicle body 12 of an 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.

[0002] P22230WO 15 November 9, 2023 Kiekert AG List of reference symbols 1 Charging connector 2 Electric and hybrid vehicles 3 Housing 4 Charging contacts / DC charging contacts 5 Fluid 6 Fluid container 7 Heat pipe 8 Wall 9 Openings 10 Coating 11 Potting compound 12 Vehicle body 13 AC charging contacts 14 Protective contact 15 Communication contacts 16 First housing part 17 Second housing part 18 Corresponding charging connector 19 Corresponding charging contacts 20 Opening 21 Corresponding protective contact 22 Corresponding communication contacts 23 Charging coupling 24 Charging cable 25 Charging station 26 Seal 27 Opening 28 Closure P22230WO 16 November 9, 2023 Kiekert AG 29 Wall

Claims

P22230WO 17 November 9, 2023 Kiekert AG Patent claims 1. Charging connector (1) for electric and hybrid vehicles (2), with a housing (3), charging contacts (4) arranged in the housing (3) for contacting corresponding charging contacts () of a corresponding charging connector (), and a fluid container (6) filled with a fluid (5) that is in thermally conductive contact with at least one of the charging contacts (4).

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

3. Charging connector according to claim 2, wherein the liquid is water or a mixture of water and another substance or an oil.

4. Charging connector according to one of the preceding claims, wherein the fluid container (6) is connected to at least one of the charging contacts (4) by means of a heat pipe (7).

5. Charging connector according to claim 4, wherein the heat pipe (7) is inserted into the charging contact (4) transversely to the longitudinal direction of the latter.Charging connector according to claim 4 or 5, wherein the charging contact (4) is pin-shaped and the heat. P22230WO 18 November 9, 2023 Kiekert AG pipe (7) runs within the charging contact (4) in its longitudinal direction.

7. Charging connector according to one of claims 1 to 3, wherein the fluid container (6) has a wall (8) with two openings (9) through which at least one of the charging contacts (4) is passed.

8. Charging connector according to claim 7, wherein the charging contact has a galvanically insulating coating (10) at least in its region within the fluid container (6).

9. Charging connector according to one of the preceding claims, 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. Charging connector according to one of the preceding claims, wherein the volume of the fluid is between 150 and 20 ml. 11.Use of a charging connector according to one of the preceding claims on the vehicle body of an electric or hybrid vehicle.

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