Charging device for charging the traction battery of an electric vehicle

Abstract

Charging device for charging a traction battery (16) of an electric vehicle (17), with a charging station (12) which has an ungrounded power supply system (18), a charging cable (14) with two electrical conductors (22, 24), an insulation fault monitoring device (30) for monitoring an insulation resistance of the ungrounded power supply system (18), and a separate test device (40) for verifying the functionality of the insulation fault monitoring device (30), characterized by the fact that The test device (40) is connected between the charging station (12) and the electric vehicle (17) and has a resistor arrangement (42) which is electrically grounded and can be optionally connected to one of the two conductors (22, 24) of the charging cable (14), wherein at least two test resistance values ​​can be set via the resistor arrangement (42) such that two fault cases can be simulated by switching between the two test resistance values.

Description

[0001] The invention relates to a charging device for charging a traction battery of an electric vehicle, comprising a charging station having an ungrounded power supply system, a charging cable with two electrical conductors, an insulation fault monitoring device for monitoring an insulation resistance of the ungrounded power supply system, and a separate test device for checking the functionality of the insulation fault monitoring device.

[0002] Furthermore, the invention relates to a test device for checking the functionality of an insulation fault monitoring device of a charging station.

[0003] In the development of electromobility, the consideration of electrical safety is becoming increasingly important. This concerns, on the one hand, the electrical hazard potential for people emanating from the vehicle's own power supply network and, on the other hand, the electrical hazard potential for people emanating from a charging station during the charging process of the electric vehicle's traction battery. The charging station can be a charging station installed in the home in the form of a wallbox or a publicly accessible charging station, which, for example, is located together with several charging stations in a charging park. The charging stations are equipped with either a grounded or an ungrounded power supply system.

[0004] Charging stations typically have an insulation monitoring device to minimize the potential electrical hazard for people. Charging stations with a grounded power system pose a high electrical hazard even with a single insulation fault, as an electrical circuit is closed between the power system and earth via the person. In such a closed circuit, a high electrical current flows through the person. Before the person can close the circuit, the insulation monitoring device detects the insulation fault, and the charging station is immediately shut down. In contrast, a first insulation fault in an ungrounded power system is not critical for people, as the lack of electrical connection between the power system and earth prevents an electrical circuit from being closed via the person.Nevertheless, the insulation fault is detected by the insulation monitoring device, and a warning is issued or the charging station is shut down. If a second insulation fault occurs and a ground fault or short circuit to the body is present due to the first insulation fault, there is a risk of an electrical circuit being closed via the person, posing a risk to the person. The second insulation fault is detected early by the insulation monitoring device, and the charging station is shut down. Otherwise, the charging station is shut down after the first insulation fault, provided it is low-resistance.

[0005] For insulation monitoring of an ungrounded power system, the insulation monitoring device has an insulation resistance value for each fault scenario. A first high insulation resistance value, defined, for example, as 500 kOhm at a charging voltage of 1000 V, detects an insulation fault as an insulation warning. A second predefined insulation resistance value, defined as 100 kOhm at a charging voltage of 1000 V, directly detects an insulation fault. The insulation monitoring device issues a warning signal if the insulation resistance value is less than 500 kOhm, and the charging station is shut down if the insulation resistance value is less than 100 kOhm.

[0006] Such an insulation monitoring device for an ungrounded power supply system is disclosed in EP 3 157 113 A1.

[0007] To determine the proper functionality of the insulation monitoring device, it must be tested after the charging station has been installed. Complex and cumbersome test devices exist for this purpose. These are connected to the live components of the power system via crocodile clips, for example, while the charging station is open. A trained worker is required to properly connect the test device, and connecting the test device poses a potential electrical hazard to the worker due to electric shock.

[0008] US 2009 / 0 085 575 A1 discloses a test device for an insulation fault monitoring device, wherein a test resistor is used to check whether the insulation fault monitoring device is triggered, depending on a set leakage current of a conductor to earth. DE 10 2016 207 197 B3 and DE 10 2017 209 663 B3 each disclose a method and a device for functional testing of an insulation monitoring device installed in an ungrounded power system. Furthermore, US 2015 / 0 346 288 A1 discloses a test device for testing an electric charging station for electric motor vehicles, with which the insulation reliability of the charging station can be tested.

[0009] The object of the invention is to provide a charging device for charging a traction battery of an electric vehicle with a test device for the insulation monitoring device, which is simple in design and operation. Furthermore, the hazard potential for the worker when connecting and operating the test device is to be minimized.

[0010] The aim is to create a simple and operable test device for checking the functionality of the insulation fault monitoring device of a charging station.

[0011] This object is achieved with the charging device for charging a traction battery of an electric vehicle having the features of independent claim 1.

[0012] Furthermore, the object is achieved by a test device for checking the functionality of the insulation fault monitoring device of a charging station according to claim 12.

[0013] According to the invention, the test device is interposed between the charging station and the electric vehicle and has a resistor arrangement that is electrically grounded and can be selectively connected to one of the two conductors of the charging cable, wherein at least one test resistance value can be set via the resistor arrangement. The fault case detectable by the insulation monitoring device is easily simulated via the test device by creating an earth fault with a predefined test resistance value via the resistor arrangement, wherein the test resistance value corresponds to the predefined resistance value of the insulation monitoring device for triggering appropriate measures in the event of an insulation fault or, within the error limits, falls below or exceeds this value to trigger a fault.

[0014] In particular, two test resistance values ​​can be set via the resistor arrangement, whereby two fault scenarios can be easily simulated by switching between the two test resistance values. In a charging station with an ungrounded power supply system, the functionality of various measures defined by the insulation monitoring device can be checked between warning and fault signals. A first test resistance value, for example, 500 kOhm at a supply voltage of 1000 V, is used to check the functionality of the insulation monitoring device with respect to a warning threshold, and a second test resistance value, for example, 100 kOhm at a supply voltage of 1000 V, is used to check the functionality of the insulation monitoring device with respect to a charging station shutdown threshold.

[0015] The test device is a self-contained system that can be easily and safely connected to the charging cable and thus to the charging station via plug elements, without any risk of electric shock to the person operating the test device. The resistance arrangement of the test device can be connected to either of the two conductors, allowing the functionality of the insulation fault monitoring device to be tested with respect to both conductors.

[0016] The test device preferably comprises a conductor switching device, wherein in a first switching position of the conductor switching device, a first electrical conductor is electrically coupled to the resistor arrangement, and in a second switching position of the conductor switching device, a second electrical conductor is electrically coupled to the resistor arrangement. The conductor switching device can be a mechanical or electronic switch that establishes an electrical connection between the resistor arrangement and either one conductor or the other conductor. The conductor switching device is, for example, a changeover switch that can be switched between at least two switching positions, wherein the middle position between the two switching positions is not necessarily stable.Alternatively, the conductor switching device is an electronic switch, with electronic components such as a field-effect transistor, a bipolar transistor, or a diode being used as switching elements. With the conductor switching device, the test device only needs to be electrically connected to the charging cable and the charging station, and the functionality of the insulation monitoring device with respect to both electrical conductors can be checked by simply switching between at least two switching positions.

[0017] In a preferred embodiment, the test device has a conductor switching actuating element coupled to the conductor switching device. The conductor switching actuating element is arranged on an outer surface of a test device housing and is designed, for example, as a rotary knob that can be adjusted between at least two locking positions. By turning the rotary knob to the first locking position, the conductor switching device is adjusted to the first switching position, and by turning the rotary knob to the second locking position, the conductor switching device is adjusted to the second switching position. The conductor switching actuating element allows the conductor switching device to be easily actuated.

[0018] Preferably, the resistor arrangement comprises a continuously variable potentiometer. A potentiometer is a resistance component whose resistance value can be mechanically adjusted. This allows for continuously variable adjustment of different test resistance values, allowing the test resistance values ​​to be easily changed at any time.

[0019] Alternatively, the resistor arrangement comprises a first test resistor with a first test resistance value and a second test resistor with a second test resistance value. A resistance switching device is provided, wherein, in a first switching position of the resistance switching device, the first test resistor is electrically coupled to one of the electrical conductors, and, in a second switching position of the resistance switching device, a second test resistor is electrically coupled to one of the electrical conductors. This allows only predefined test resistance values ​​to be set to test the insulation fault monitoring device, thus creating an easily operable test device.

[0020] Preferably, the test device comprises a resistance switching actuator coupled to the resistance switching device. The resistance switching actuator is arranged on an outer surface of a test device housing, allowing easy switching between multiple test resistors.

[0021] In a preferred embodiment, the test device has a combination switch actuator, which is coupled to the conductor switching device and the resistance switching device. This eliminates the need for an actuator, thus reducing manufacturing and assembly costs. The combination switch actuator can, for example, have four locking positions, with two locking positions provided for each electrical conductor, and two different test resistances can be set via the two locking positions per conductor.

[0022] Preferably, the charging cable has a vehicle-side connection element and a charging station-side connection element, provided the charging station side is not permanently connected. The testing device has a vehicle-side coupling element and a charging station-side coupling element. The vehicle-side coupling element of the testing device complements a charging station-side connection element of the charging cable, and the charging station-side coupling element of the testing device corresponds to the charging station-side connection element of the charging cable, provided the charging station side is not permanently connected. This allows the testing device to be easily interposed between the charging cable and the charging station.

[0023] The coupling elements are preferably CCS, CHAdeMO, or GBT connectors, allowing the test device to be connected to the charging cable or charging station via standardized coupling elements. This allows the test device to be connected to different charging stations and charging cables.

[0024] In a preferred embodiment, the test device is designed to be self-supporting, requiring no additional components to support it. This makes the test device handy and mobile.

[0025] Preferably, the test device comprises a display device for displaying the set test resistance value, whereby the set conductor and / or the set test resistance value are displayed to the person operating the test device.

[0026] An embodiment of the invention is explained in more detail with reference to the drawings. Fig. 1 shows schematically a charging device according to the invention with a first embodiment of the test device, Fig. 2 schematically shows a charging device according to the invention with a second embodiment of the test device.

[0027] Fig. 1 and Fig. 2 show a charging device 10 for charging a traction battery 16 of an electric vehicle 17. The charging device 10 has a charging station 12 which is electrically connected to the traction battery 16 for charging the traction battery 16.

[0028] The charging station 12 has a power supply system 18, which serves as a direct current source and is not grounded. The charging station 12 also has an insulation fault monitoring device 30, which is grounded and serves to monitor the ungrounded power supply system 18. The insulation fault monitoring device 30 has two predefined insulation resistance values. The first insulation resistance value serves as a warm threshold; as soon as the first insulation resistance value is undershot, a warning about an insulation fault is issued by the insulation fault monitoring device 30. The second insulation resistance value serves as a shutdown threshold; as soon as the second insulation resistance value is undershot, the insulation fault monitoring device 30 issues a command to shut down the charging station.

[0029] The traction battery 16 of the electric vehicle 17 is electrically connected to the ungrounded power supply system 18 via a charging cable 14. The charging cable 14 has a first conductor 22 and a second conductor 24, wherein the first conductor 22 is the negative DC phase and the second conductor 24 is the positive DC phase.

[0030] In order to check the functionality of the insulation fault monitoring device 30, a test device 40 according to the invention is interposed between the charging station 12 and the electric vehicle 17. The test device 40 has a test device housing 44, on which a vehicle-side coupling element 74 or directly a charging cable and a charging station-side coupling element 76 are arranged. The vehicle-side coupling element 74 is designed to complement a charging station-side connection element 72 of the charging cable 14, unless the charging cable is directly part of the test device. The charging station-side coupling element 76 corresponds to the charging station-side connection element 72 of the charging cable 14. The test device 40 is electrically connected to the charging station 12 via the charging station-side coupling element 76, either directly or via an additional charging cable, which is designed identically to the charging cable 14. The charging cable 14 is coupled to the vehicle-side coupling element 74 of the test device 40 via the charging station-side connection element 72 and is coupled to the charging station 12 via a charging station-side connection element 70.The coupling elements 74, 76 of the test device 40 as well as the connection elements 70, 72 are standardized components of, for example, a CCS, CHAdeMo or GB / T plug-socket system.

[0031] The test device 40 comprises a resistor assembly 42 and a conductor switching device 50, wherein an electrical connection is established between the resistor assembly 42 and one of the two electrical conductors 22, 24 via the conductor switching device 50. The conductor switching device 50 can be switched between two switching positions, wherein in the first switching position the resistor assembly 42 is connected to the first conductor 22, and in the second switching position the resistor assembly 42 is electrically connected to the second electrical conductor 24.

[0032] To actuate the conductor switching device 50, a conductor switching actuating element 46 is provided on the test device housing 44. This actuating element is designed as a rotary knob and is arranged on an outer surface of the test device housing 44. The conductor switching actuating element 46 is mechanically connected to the conductor switching device 50, so that an adjustment of the conductor switching actuating element 46 results in a switching movement of the conductor switching device 50, wherein the conductor switching device 50 is designed as a mechanical switching element. Alternatively, the conductor switching device 50 could be implemented electronically using electronic components, wherein the adjustment of the conductor switching actuating element 46 is detected and a switching movement of the conductor switching device 50 is triggered.

[0033] The resistor arrangement 42 in Fig. 1 is designed as a potentiometer, via which the resistance value of the resistor arrangement 42 can be continuously adjusted between two predefined test resistance values. The test resistance value of the potentiometer can be set via a potentiometer actuating element 48 arranged on the test device housing 44, and the set test resistance value is displayed via an optional display device 80 arranged on the test device housing 44. In addition, the display device 80 indicates which electrical conductor 22, 24 is switched by the conductor switching device 50. The resistor arrangement 42 is electrically connected to the grounded insulation fault monitoring device 30 via a grounding conductor 31 and is thus grounded.

[0034] In contrast to the resistor arrangement 42 in Fig. 1 is the resistor arrangement 42 in Fig. 2 is not designed as a potentiometer, but rather has two separate test resistors 43, 45 and a resistance switching device 60. The test resistors 43, 45 each have a predefined test resistance value. The resistance switching device 60 is adjustable between two switching positions, wherein in a first switching position, the first test resistor 43 is electrically connected to one of the two conductors 22, 24, and in the second switching position, the second test resistor 45 is electrically connected to one of the conductors 22, 24.

[0035] In addition, the test device 40 differs in Fig. 2 of the Fig.1 in that, instead of a conductor switching actuating element 46, a combination switching actuating element 49 is arranged on the test device housing 44, wherein the combination switching actuating element 49 is coupled to the conductor switching device 50 and the resistor switching device 60. The combination switching actuating element 49 has four switching positions, wherein in the first switching position the first conductor 22 is electrically connected to the first test resistor 43, in the second switching position the first conductor 22 is electrically connected to the second test resistor 45, in the third switching position the second conductor 24 is electrically connected to the first test resistor 43, and in the fourth switching position the second conductor 24 is electrically connected to the second test resistor 45.

[0036] To test the functionality of the insulation fault monitoring device 30 using the test device 40 according to the invention, the resistor arrangement 42 is electrically connected to the first conductor 22 via the conductor switching device 50, and the predefined test resistance values ​​are set sequentially either via the potentiometer or via the resistance switching device 60. Depending on the set test resistance value, a warning function or a shutdown function is triggered in the insulation fault monitoring device 30.

[0037] In the next step, the second conductor 24 is electrically coupled to the resistor arrangement 42 by switching the conductor switching device 50, wherein the different test resistance values ​​are again set one after the other and, depending on the set test resistance value, a warning function or a shutdown function is triggered in the insulation fault monitoring device 30.

Claims

[1] Charging device for charging a traction battery (16) of an electric vehicle (17), with a charging station (12) having an ungrounded power supply system (18), a charging cable (14) with two electrical conductors (22, 24), an insulation fault monitoring device (30) for monitoring an insulation resistance of the unearthed power supply system (18), and a separate test device (40) for checking the functionality of the insulation fault monitoring device (30), characterized by , that the test device (40) is interposed between the charging station (12) and the electric vehicle (17) and has a resistance arrangement (42) which is electrically earthed and can be selectively connected to one of the two conductors (22, 24) of the charging cable (14), wherein at least two test resistance values ​​can be set via the resistance arrangement (42) in such a way that two fault cases can be simulated by switching between the two test resistance values. [2] Charging device according to claim 1, characterized by that the test device (40) has a conductor switching device (50), wherein in a first switching position of the conductor switching device (50) a first electrical conductor (22) is electrically coupled to the resistor arrangement (42) and in a second switching position of the conductor switching device (50) a second electrical conductor (24) is electrically coupled to the resistor arrangement (42). [3] Charging device according to claim 1 or 2, characterized by that the test device (40) has a conductor switching actuating element (46) which is coupled to the conductor switching device (50). [4] Charging device according to one of the preceding claims, characterized by that the resistor arrangement (42) has a continuously variable potentiometer. [5] Charging device according to one of claims 1 to 3, characterized byin that the resistor arrangement (42) has a first test resistor (43) with a first test resistance value and a second test resistor (45) with a second test resistance value, wherein a resistor switching device (60) is provided, wherein in a first switching position of the resistor switching device (60) the first test resistor (43) is electrically coupled to one of the electrical conductors (22, 24) and in a second switching position of the resistor switching device (60) a second test resistor (45) is electrically coupled to one of the electrical conductors (22, 24). [6] Charging device according to claim 5, characterized by that the test device (40) has a resistance switching actuating element (48) which is coupled to the resistance switching device (60). [7] Loading device according to claims 2 and 6, characterized bythat the test device (40) has a combination switching actuating element which is coupled to the conductor switching device (50) and to the resistance switching device (60). [8] Charging device according to one of the preceding claims, characterized by in that the charging cable (14) has a vehicle-side connection element (70) and a charging station-side connection element (72), and the testing device has a vehicle-side coupling element (74) and a charging station-side coupling element (76), wherein the vehicle-side coupling element (74) of the testing device (40) is complementary to a charging station-side connection element (72) of the charging cable (14), and the charging station-side coupling element (76) of the testing device (40) corresponds to the charging station-side connection element (72) of the charging cable (14), provided that the charging station side is not firmly connected. [9] Loading device according to claim 8, characterized bythat the coupling elements (74, 76) are CCS, CHAdeMO or GBT connections. [10] Charging device according to one of the preceding claims, characterized by that the test device (40) is designed to be self-supporting. [11] Charging device according to one of the preceding claims, characterized by that the test device (40) has a display device (80) for displaying the set test resistance value. [12] Test device for checking the functionality of the insulation fault monitoring device of a charging station according to one of claims 1 to 11.

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