Charging plug-in connector for electric and hybrid vehicles

Abstract

The invention relates to a charging plug-in connector (1) for electric and hybrid vehicles (18), comprising charging contacts (2) and at least one heat store (5) having a housing (6), wherein the heat store (5) makes thermally conductive contact with at least one charging contact (2), so that it is possible to dissipate heat from the charging contact (2) to the heat store (5), and a fluid and a phase-change material enclosed in at least one capsule (8) having a non-soluble shell are arranged in the housing (6). In this way, heat dissipation is improved for a charging plug-in connector (1) that is not itself equipped with a cooling system from a charging station.

Description

[0001] Charging connectors for electric and hybrid vehicles

[0002] The invention relates to a charging connector for electric and hybrid vehicles, with charging contacts and at least one heat accumulator having a housing, wherein the heat accumulator makes thermally conductive contact with at least one charging contact.

[0003] Electric and hybrid vehicles have a rechargeable energy storage device, usually a high-voltage battery, which supplies energy to an electric drive motor during operation. The storage capacity of these high-voltage batteries is limited, so they must be recharged regularly at a charging station. The battery is charged using a charging cable provided between the charging station and the vehicle. The charging cable, for example, in accordance with European standard IEC 62196 Type 2, is equipped with a charging plug on one end that can be plugged into a charging socket provided on the charging station, and with a charging coupling on the other end that can be connected to a charging plug installed in the electric or hybrid vehicle. For the purposes of this article, charging sockets, charging plugs, charging couplings and charging plugs are all referred to as “charging connectors”.Charging sockets and charging couplings have contact sleeves as charging contacts, and charging plugs and 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. As explained, for example, in EP 3 043 421 A1, a charging current flowing through the charging connector heats up due to ohmic current heat losses. However, the heating of the charging connector is legally limited to a limit temperature increase. For example, according to standard IEC 62196-3 the limit temperature increase is limited to 50 K. This in turn leads to a maximum charging current for largely standardized connector geometries that cannot generally exceed 200 A in continuous load operation.However, with intermittent charging of the battery of an electric or hybrid vehicle, higher charging currents are required over limited periods of time to charge the battery in the desired short time. This leads to temporary heating of the charging connectors, which exceeds the limit temperature increase. However, the cable cross-section of the electrical connector bodies cannot be increased indefinitely, since the connector geometries are standardized and, in addition, the smallest possible amount of conductive material, usually copper, should be used for the electrical connector bodies.

[0004] According to EP 3 043 421 A1, an electrical connection body is provided which enables increased charging currents with limited heating and therefore has an increased short-time current carrying capacity. For this purpose, an electrical connection body for a charging plug or a charging socket is proposed, wherein the electrical connection body has a first connection region for the galvanic connection to an electrical energy receiver and a second connection region for the 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 which is arranged in a charging station.

[0005] Cooling of a charging plug connector for electric and hybrid vehicles, which cooling starts at the side of the charging station, is also well known from the prior art. DE 10 2015 119 338 A1 describes, for example, two connection points for coolant lines being arranged on a contact sleeve element of a charging plug. Coolant is guided in a circle around the contact sleeve element by means of a spiral-shaped plug-in 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 3 433 902 B1 likewise describes a plug connector part with cooled contact elements. Here, too, the supply of coolant via coolant lines to the contact elements of the charging socket connected to the charging cable is provided on the charging station side.A fluid is provided as a coolant, which is guided perpendicular to the contact element into the hollowed contact element and flows back within the contact element.

[0006] Finally, 10 2016 105 361 B4 also describes a connector part with a cooled contact element. Here, too, a coolant is supplied via coolant lines to the contact elements of a charging socket connected to the charging cable on the charging station side. Guide elements are arranged on the contact elements to ensure that the coolant, in the form of compressed air, flows around the contact elements.

[0007] However, solutions are also known from the state of the art which can also be used with a charging connector which is not cooled directly by the charging station, such as a charging connector built into the vehicle body of an electric or hybrid vehicle, such as a built-in charging connector according to the European standard IEC 62196 Type 2.

[0008] For example, DE 10 2016 107 409 A1 describes a plug connector part for connecting to a mating connector part, which comprises a housing which has a plug-in section for plugging into the mating connector part and a contact element arranged on the plug-in section for making electrical contact with an associated mating contact element of the mating connector part. In addition, a heat pipe connected to the contact element and a heat sink arranged in the housing are provided, which heat sink is in thermally conductive connection with the contact element for dissipating heat from the contact element via the heat pipe. In this way, a plug connector part with a contact element is provided which can have a high current-carrying capacity, for example for use in a charging system for charging an electric vehicle.

[0009] Furthermore, DE 20 2019 102 461 U1 describes a plug connector part for connecting to a mating connector part, comprising a housing, a plug-in section arranged on the housing for plugging into the mating connector part, an electrical contact element arranged on the plug-in section for transmitting a current between the plug connector part and the mating connector part, and a cooling element arranged on the contact element for cooling the contact element, wherein a fan device is provided for generating an air flow at the cooling element. However, this system and the system described in DE 10 2016 107 409 A1 are very complex.

[0010] Based on this, the object of the present invention is to achieve improved heat dissipation in a charging connector which is not itself equipped with a cooling system on the part of a charging station.

[0011] This object is achieved by the subject matter of the independent claims. Preferred developments of the invention are described in the subclaims.

[0012] According to the invention, a charging connector for electric and hybrid vehicles is thus provided, with charging contacts and at least one heat accumulator having a housing, wherein the heat accumulator contacts at least one charging contact in a thermally conductive manner, so that heat can be dissipated from the charging contact to the heat accumulator, and a fluid and a phase change material enclosed in at least one capsule having a non-soluble shell are arranged in the housing.

[0013] In this case, a heat storage device is used if the charging connector is equipped with this heat storage device as an additional element whose sole function is to absorb and store the heat generated during the charging process. In particular, this heat can be stored more effectively with a heat storage device than with the charging contact itself, so that the heating of other components of the charging connector can be delayed.

[0014] What is essential to the invention is that at least one capsule with a phase change material is arranged in the heat accumulator and is surrounded by a fluid. On the one hand, the fluid absorbs and stores heat from the charging contact, and on the other hand, the heat absorbed with the fluid can be evenly released to the capsule. In this case, the capsule is a preferably spherical container. For this purpose, the capsule has a non-soluble, thermally conductive shell, in which the phase change material is arranged. In this context, non-soluble means that the shell remains in the fluid and does not react chemically with it in a way that would lead to the shell dissolving in the fluid. With the phase change material in the capsule, a latent heat accumulator is formed in the capsule based on the utilization of the enthalpy of thermodynamic changes in state of a storage medium.The principle used here is the exploitation of the phase transition from the solid phase to the liquid phase, i.e., the transition from a solidified medium to a molten medium. For this purpose, the heat storage device contains a phase-change material. Phase-change materials are materials that can release or absorb heat or cold during their phase change, depending on their respective melting point and the ambient temperature.

[0015] The amount of energy stored in the temperature range of the phase change is significantly greater than the energy absorption in an equally large temperature interval during heating without a phase transition. During such heating without a phase transition, the energy absorption is determined solely by the specific heat capacity of the respective material. Therefore, phase-change materials have an advantage in terms of heat storage density, especially at small temperature differences.

[0016] When a phase-change material is heated and its temperature approaches its melting point, the heat absorbed by the phase-change material is used to complete the phase change. Therefore, during the transition from the solid phase to the liquid phase, there is no temperature increase. Once the phase-change material is completely liquid, the phase-change material continues to heat up as before the phase transition.

[0017] Because the phase-change material does not heat up further during the phase transition, the heating is delayed compared to heating without a phase transition. This is exploited according to the invention to keep the temperature at the charging contact, which is in thermally conductive contact with the heat storage device, as low as possible. This makes it possible to extend the time during a charging process until a critical temperature is reached, at which the charging process must be interrupted.

[0018] It is also essential that the capsule is provided with an insoluble shell. This prevents the phase-change material in the liquid phase from escaping into the fluid and mixing with it. The phase change is therefore reversible.

[0019] The heat accumulator can be designed integrally with the charging contact so that the heat can be absorbed in the charging contact itself. However, the heat accumulator can also enclose the charging contact in a thermally conductive manner in order to enable advantageous dissipation of the heat during the charging process. Likewise, it can be provided that the charging contact is thermally conductively connected to the heat accumulator by means of a heat conducting element. In the present case, a heat conducting element is understood to be an element which results in the thermal conductivity between the charging contact, to which the heat conducting element is connected, and the heat accumulator, to which the heat conducting element is also connected, in the charging plug connector according to the invention being better than without the heat conducting element. The installation of the heat conducting element therefore improves the possibility of dissipating heat generated on or in the charging contact to the heat accumulator.

[0020] In principle, the capsule can be made of various materials. However, according to a preferred embodiment of the invention, the shell comprises a metallic material. It is particularly preferred here for the shell of the capsule to be provided with a copper material. Metallic materials generally have high thermal conductivity. Copper has a particularly high thermal conductivity in this case. However, it is also possible for the metallic material to contain further admixtures such as nickel or silver, with which the thermal conductivity can be increased even further.

[0021] The casing can, however, also comprise a plastic material. Plastics can also have good thermal conductivity, but are lighter than metallic materials. Depending on the requirements of the charging connector, capsules can therefore be provided which, for example, are provided with the plastic material in the casing for reasons of weight reduction. In this context, according to a preferred development of the invention, the heat accumulator is provided with a plurality of capsules, wherein the capsules are arranged as granules in the housing, and the fluid flows around the capsules. Based on the material composition above, the granules can comprise capsules which are provided with the plastic material and with the metallic material in the casing.

[0022] The capsules are preferably shaped so that, as granules in the heat storage unit, they form spaces between the capsules, in which the fluid is then located. Thermal forces and the resulting change in the fluid's density create a flow that sets the fluid in motion, causing the fluid to flow in the spaces formed by the capsules and thus flow around the capsules. This improves the heat distribution in the heat storage unit, ensuring that the capsules are homogeneously exposed to heat.

[0023] In principle, the capsules can have different diameters. However, according to a preferred development of the invention, the capsule has a diameter of between 2 mm and 5 mm. The granules are therefore in the form of microgranules. By reducing the capsule size, the phase change material in the capsules heats up more homogeneously. At the same time, the diameter is selected so that the ratio of shell to phase change material of the individual capsule ensures a high heat storage capacity with the granules. In principle, the fluid can be formed from various substances. However, according to a preferred development of the invention, the fluid is a mixture of water and glycol or an oil. The oil can be, for example, a mineral oil, a vegetable oil, or a silicone oil.

[0024] In this context, however, it can also be provided that the fluid is a further phase change material and the melting temperature of the further phase change material is lower than the melting temperature of the other phase change material. The capsules are therefore initially embedded in the further phase change material and surrounded by it. During the charging process, the heat storage device absorbs the heat dissipated by the charging contact and the further phase change material heats up. The thermally conductive shells of the capsules act like heat conducting elements in the heat storage device itself and contribute to a uniform heating of the further phase change material. When the further phase change material finally enters the liquid phase, the liquid further phase change material circulates and thus enables the phase change material in the capsules to be heated evenly.

[0025] The invention also relates to the use of a system as described above on the vehicle body of an electric or hybrid vehicle.

[0026] The invention further relates to a system comprising a charging plug connector, as described above, and a charging plug connector corresponding thereto, having corresponding charging contacts, wherein the corresponding charging plug connector is provided with a cooling element that can be supplied with a cooling fluid and the corresponding charging contacts of the corresponding charging plug connector are designed as contact sleeves into which the charging contacts of the charging plug connector, designed as contact pins, can be inserted.

[0027] When we talk about a corresponding charging connector in the present case, we mean, on the one hand, a charging connector which has the same plug-in face as the charging connector, but one plug-in face has contact pins while the other plug-in face has contact sleeves, and vice versa. The set comprising the charging connector and the corresponding charging connector can therefore be plugged together. On the other hand, we also talk about a corresponding charging connector in the present case when the plug-in faces in the aforementioned sense only partially correspond, i.e. the corresponding charging connector, for example, does not have all of the contacts which are present in the charging connector, but the existing contacts of the corresponding charging connector correspond to the charging connector in terms of the plug-in face, so that the charging connector and the corresponding charging connector can also be plugged together in this case.One such case is a charging connector connected to a charging cable for direct current charging in accordance with the European standard IEC 62196 Type 2. Such a charging connector can be plugged into a charging plug installed in the body of an electric or hybrid vehicle and suitable for both alternating current and direct current charging, whereby the alternating current plug face of the direct current charging connector only contains the communication contacts and the protective contact, but no contacts for the outer conductor and a center conductor for alternating current charging.

[0028] An outer conductor (also known colloquially as a phase conductor) is a conductor which is live during normal operation and can contribute to the transmission or distribution of electrical energy, but is not a neutral conductor. A neutral conductor is a conductor which is electrically connected to the neutral point and is able to contribute to the distribution of electrical energy. In the European standard IEC 62196 Type 2, the contacts which are referred to here as AC charging contacts are designated LI, L2 and L3 (outer conductor) and N (neutral conductor), and the DC charging contacts are designated DC+ and DC-. This understanding should not be contradicted by the fact that the European standard IEC 62196 Type 2 also recognises an operating mode according to which direct current charging takes place via the contacts LI, L2, L3 and N.

[0029] The system is preferably designed such that it further comprises a charging station and a charging cable connected to the charging station and carrying the corresponding charging connector, wherein the charging station has a cooling fluid source and the charging cable is provided with cooling fluid lines in order to transport the cooling fluid from the cooling fluid source to the cooling element of the corresponding charging connector and back again. The cooling fluid source of the charging station is designed such that heated cooling fluid returned from the charging connector is cooled again so that it is available again for cooling.

[0030] The invention is described in more detail below with reference to the drawings using preferred embodiments.

[0031] The drawings show

[0032] Fig. 1 shows a charging connector according to a preferred

[0033] Embodiment of the invention in a perspective view,

[0034] Fig. 2 shows a connector corresponding to the connector shown in Fig. 1,

[0035] Fig. 3a shows schematically an arrangement with charging contact and a heat accumulator in a sectional view,

[0036] Fig. 3b schematically shows a further arrangement with a charging contact and a heat accumulator in a sectional view and Fig. 4 schematically shows a system with a charging connector, a corresponding charging connector, a charging cable, a charging station and a cooling system according to a preferred embodiment of the invention.

[0037] Fig. 1 shows a perspective view of a charging plug connector 1 according to a preferred exemplary embodiment of the invention. This is a charging plug for installation in the vehicle body 17 of an electric or hybrid vehicle 18, as shown schematically in Fig. 4. The present charging plug connector 1 is essentially, in terms of its plug face, a charging plug according to the European standard IEC 62196 Type 2. In addition to AC charging contacts (not further provided with reference symbols), a protective contact and communication contacts, the charging plug connector 1 has two DC charging contacts 2 for DC charging.

[0038] The charging connector 1 can be coupled to a corresponding charging connector 4, which is shown in Fig. 2. This is a charging coupling that can be attached to a charging cable and plugged together with the charging plug. The charging coupling shown here as an example is one for direct current charging and therefore has corresponding direct current charging contacts 3, a protective contact and communication contacts. Both the charging plug shown here and the coupling shown here correspond to the European standard IEC 62196 in terms of their plug-in face. Fig. 3a shows a sectional view of the charging contact 2 with a heat accumulator 5. The heat accumulator 5 has a housing 6 that encloses the charging contact 2 in a thermally conductive manner. The housing 6 of the heat accumulator 5 contains a fluid that flows around capsules 8. The fluid is a mixture of water and glycol.The capsules 8 are provided with insoluble shells that enclose a phase-change material, thus separating it from the fluid. This allows the phase-change material to change its phase in a reversible process without flowing into the fluid.

[0039] Fig. 3b shows a further arrangement according to the invention comprising the charging contact 2 and the heat accumulator 5. In this case, the heat accumulator 5 is formed integrally with the charging contact 2. The housing 6 of the heat accumulator 5 is formed by two interconnected parts of the charging contact 2. Analogous to the arrangement in Fig. 3a, the fluid and the capsules 8 are contained in the housing 6.

[0040] It has already been mentioned above that the charging connector 1 is used in the form of a built-in plug on the vehicle body 17 of an electric or hybrid vehicle 18. In this context, reference is made to Fig. 4, which schematically shows a system according to a preferred exemplary embodiment of the invention, which system comprises a charging connector 1 installed in a vehicle body 17 of an electric or hybrid vehicle 18, a charging connector 4 corresponding to it, a charging station 20 and a charging cable 21 connected to the charging station 20 and carrying the corresponding charging connector 1. What is essential in this preferred exemplary embodiment of the invention is that the corresponding charging connector 4 is provided with a cooling element 19 to which a cooling fluid can be applied for cooling the corresponding charging contacts 3.In order to achieve cooling of the corresponding charging contacts 3 via the cooling elements 19, the charging station 20 is provided with a cooling fluid source 14 and the charging cable 21 has cooling fluid lines 22 in order to transport the cooling fluid from the cooling fluid source 14 to the cooling element 19 of the corresponding charging connector 4 and back again.

[0041] Because the charging connector 1 installed in the vehicle body 17 of the electric or hybrid vehicle 18 is now brought into engagement with the corresponding charging contacts 3 on the charging station side during the charging process, the heat generated during the charging process is, on the one hand, absorbed in the heat accumulator 5 and, on the other hand, subjected to the charging station-side cooling through the thermal coupling between the charging connector 1 installed in the vehicle body 17 of the electric or hybrid vehicle 18 and the corresponding charging connector 4 attached to the charging cable 21 when the two charging connectors 1, 4 are plugged in. In this way, the active cooling in the corresponding charging connector 4 with the cooling fluid originating from the cooling fluid source can also be indirectly used for cooling the charging connector 1 installed in the vehicle body 17 of the electric or hybrid vehicle 18. List of reference symbols

[0042] 1 charging connector

[0043] 2 charging contact 3 corresponding charging contact

[0044] 4 corresponding charging connectors

[0045] 5 heat storage

[0046] 6 housings

[0047] 8 Capsule 14 Cooling fluid source

[0048] 17 Vehicle body

[0049] 18 Electric or hybrid vehicle

[0050] 19 Cooling element

[0051] 20 Charging station 21 Charging cable

[0052] 22 cooling fluid lines

Claims

Patent claims 1. Charging connector (1) for electric and hybrid vehicles (18), with charging contacts (2) and at least one heat accumulator (5) having a housing (6), wherein the heat accumulator (5) makes thermally conductive contact with at least one charging contact (2) so that heat can be dissipated from the charging contact (2) to the heat accumulator (5), and a fluid and a phase change material enclosed in at least one capsule (8) having a non-soluble shell are arranged in the housing (6).

2. Charging connector (1) according to claim 1, wherein the shell comprises a metallic material.

3. Charging connector (1) according to claim 1, wherein the shell comprises a plastic material.

4. Charging connector (1) according to one of the preceding claims with a plurality of capsules (8), wherein the capsules (8) are arranged as granules in the housing (6), and the fluid flows around the capsules (8).

5. Charging connector (1) according to one of the preceding claims, wherein the capsule (8) has a diameter between 2 mm and 5 mm.

6. Charging connector (1) according to one of the preceding claims, wherein the fluid is a mixture with water and glycol or an oil.

7. Charging connector (1) according to one of claims 1 to 5, wherein the fluid is another phase change material, and the melting temperature of the another phase change material is lower than the melting temperature of the other phase change material.

8. Use of a charging connector according to one of the preceding claims on the vehicle body (17) of an electric or hybrid vehicle (18).

9. System comprising a charging plug connector (1) according to one of claims 1 to 7 and a charging plug connector (4) corresponding thereto and having corresponding charging contacts (3), wherein the corresponding charging plug connector (4) is provided with a cooling element (19) which can be acted upon by a cooling fluid and the corresponding charging contacts (3) of the corresponding charging plug connector (4) are designed as contact sleeves into which the charging contacts (2) of the charging plug connector (1), designed as contact pins, can be inserted.

10. System according to claim 9, further comprising a charging station (20) and a charging cable (21) connected to the charging station (20) and carrying the corresponding charging connector (4), wherein the charging station (20) has a cooling fluid source (14) and the charging cable (28) is connected to Cooling fluid lines (22) are provided to transport the cooling fluid from the cooling fluid source (14) to the cooling element (19) of the corresponding charging connector (4) and back again.

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