Vehicle equipped with a high-voltage on-board electrical system and method for operating a high-voltage on-board electrical system

Abstract

The present invention relates to a vehicle (4) comprising a high-voltage in-vehicle electrical system (3) having an electric vehicle battery (5), a charging terminal (6) for connection to a DC charging station (2), high-voltage potential lines (HV+L, HV-L), and a reference potential line (ML). According to the present invention, a DC-DC converter (7) is arranged in one of the high-voltage potential lines (HV+L, HV-L), and a series circuit comprising a varistor (8) and a current measuring device (9) is arranged between the other high-voltage potential line (HV-L, HV+L) and the reference potential line (ML). When the current intensity measured by the current measuring device (9) exceeds at least one predetermined limit value, a processing unit (10) connected to the current measuring device (9) and the DC-DC converter (7) switches off the DC-DC converter (7), or DC-DC converters (7) are respectively arranged in the two high-voltage potential lines (HV+L, HV-L), and series circuits each comprising a varistor (8) and a current measuring device (9) are respectively arranged between each high-voltage potential line (HV+L, HV-L) and the reference potential line (ML). When the current intensity measured by at least one of the current measuring devices (9) exceeds at least one predetermined limit value, the processing unit (10) connected to each current measuring device (9) and the DC-DC converter (7) switches off the DC-DC converter (7).

Description

Technical Field

[0001] The present invention relates to a vehicle equipped with a high-voltage vehicle electrical system characterized by the features of the superordinate concept of claim 1 and a method for operating the high-voltage vehicle electrical system.

Background Art

[0002] From the prior art as described in Patent Document 1, an energy coupler for electrically connecting an electric vehicle electrical system and a method for electrically connecting an electric vehicle electrical system are known. An energy coupler for electrically connecting a first electric vehicle electrical system to which a first DC voltage is applied to a second electric vehicle electrical system to which a second DC voltage is applied has a first clock-controlled energy converter and a second clock-controlled energy converter each having an in-vehicle electrical system terminal and an intermediate circuit terminal. The in-vehicle electrical system terminal of the first clock-controlled energy converter is connected to the first in-vehicle electrical system, and the in-vehicle electrical system terminal of the second clock-controlled energy converter is connected to the second in-vehicle electrical system. The intermediate circuit terminals of the first clock-controlled energy converter and the second clock-controlled energy converter are connected to a common DC intermediate circuit. The first potential of the DC intermediate circuit is electrically connected to one of the potentials of the first in-vehicle electrical system using the first clock-controlled energy converter. The second potential of the DC intermediate circuit is electrically connected to one of the potentials of the second in-car electrical system using the second clock-controlled energy converter.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem on which the present invention is based is to provide a vehicle equipped with a high-voltage onboard electrical system that is improved compared to the prior art, and an improved method for operating the high-voltage onboard electrical system. [Means for solving the problem]

[0005] This problem is solved by the present invention by a vehicle equipped with a high-voltage onboard electrical system having the features of claim 1, and a method for operating a high-voltage onboard electrical system having the features of claim 6. Advantageous embodiments of the present invention are subject to the dependent claims.

[0006] The vehicle has an electrical high-voltage onboard electrical system. The term "high voltage," sometimes abbreviated as HV, is understood to mean a DC voltage greater than approximately 60V. In particular, the term "high voltage" must be interpreted in accordance with the standard ECE R 100.

[0007] The high-voltage on-board electrical system comprises an electric vehicle battery, charging terminals for electrically connecting to an external DC charging station, a high-voltage positive potential line, a high-voltage negative potential line, and a reference potential line. The electric vehicle battery is equipped with at least one electric drive mechanism for driving the vehicle in order to supply electrical energy. Therefore, the vehicle is specifically an electric vehicle or a hybrid vehicle.

[0008] In one embodiment of the present invention, a DC-DC converter is placed on one of the high-voltage potential lines, and a series circuit consisting of a varistor and a current measuring device is placed between the other high-voltage potential line and a reference potential line. Furthermore, in the embodiment of the present invention, a processing unit connected to the current measuring device and the DC-DC converter is provided, and this processing unit is designed and configured to switch off the DC-DC converter when the current intensity measured by the current measuring device exceeds at least one predetermined limit value.

[0009] In the method according to the present invention for operating the high-voltage on-board electrical system of the vehicle of this embodiment, a current measuring device is evaluated by a processing unit, and if the current intensity measured by the current measuring device exceeds at least one predetermined limit value, the DC-DC converter is switched off.

[0010] In an alternative embodiment of the present invention, a DC-DC converter is provided on each of the two high-voltage potential lines, and a series circuit consisting of a varistor and a current measuring device is provided between each high-voltage potential line and a reference potential line. Furthermore, in this alternative embodiment of the present invention, a processing unit is provided that is connected to each current measuring device and DC-DC converter, and this processing unit is designed and configured to switch off the DC-DC converter when the current intensity measured by at least one of the current measuring devices exceeds at least one predetermined limit value.

[0011] In the method according to the present invention for operating a high-voltage on-board electrical system of a vehicle in this alternative embodiment, a current measuring device is evaluated by a processing unit, and if the current intensity measured by at least one of the current measuring devices exceeds at least one predetermined limit value, the DC-DC converter is switched off.

[0012] By using one or two DC-DC converters, it becomes possible to charge electric vehicle batteries at a DC charging station at a charging voltage lower than the battery voltage of the electric vehicle battery itself. For example, it becomes possible to charge an 800V electric vehicle battery at a DC charging station at a charging voltage of 400V or 500V. The DC-DC converter, or each DC-DC converter, is configured in particular as a galvanically coupled DC-DC converter. This is an inexpensive solution that saves structural space. However, a problem is that if an insulation failure occurs in the vehicle, it may directly result in another insulation failure occurring at the opposite high potential on the DC charging station side. Many DC charging station manufacturers install varistors between the reference potential and the high-voltage positive potential or between the reference potential and the high-voltage negative potential in the DC charging station to protect the insulation. This varistor in the DC charging station has a terminal voltage of, for example, 500V to 550V. If this varistor in the DC charging station operates or the insulation breaks down, a short circuit occurs in the electric vehicle battery. This short circuit, in the so-called CHAdeMO charging standard, results in the destruction of the ground potential wire in the charging cable that electrically connects the vehicle to the DC charging station. This is because this ground potential wire is extremely thin. Currently, the limits are 100 mAs to protect the varistor in the DC charging station and 7000 As to protect the ground potential wire in the charging cable. 2 This is defined.

[0013] This problem is solved by the solution according to the present invention. This is because, in the solution according to the present invention, if an insulation failure occurs in the vehicle's high-voltage onboard electrical system, and there is a possibility that the insulation part on the DC charging station side may be exposed to an excessively high applied voltage, the corresponding varistor in the vehicle's high-voltage onboard electrical system will first transition to a low-resistance state. For this reason, in particular, the varistor in the first embodiment of the present invention described above, or each varistor in the alternative embodiment of the present invention described above, is configured to transition to a low-resistance state when a predetermined voltage lower than, for example, 500V, is exceeded for the DC charging station outside the vehicle to which the charging terminals are electrically connected. Thus, this predetermined voltage is, for example, 450V. In addition, the varistor, or each varistor, has a corresponding characteristic curve. Therefore, the varistor transitions to a low-resistance state before the DC charging station's design voltage is exceeded.

[0014] Using the current measurement of the applicable current measuring device, the generated conductive path can be measured quickly and without interference. Through evaluation using the processing unit, this measured current, i.e., the current intensity of that current, is compared with at least one predetermined limit value or a plurality of predetermined limit values, and when necessary, i.e., when the limit value is exceeded, one or more DC-DC converters are switched off very quickly. In other words, the function of the DC-DC converters is stopped.

[0015] For example, the processing unit is connected to a contactor of an electric vehicle battery and / or to an isolator located on at least one of the high-voltage potential lines. In this case, the processing unit is designed and configured to activate the contactor and / or at least one isolator for isolation if the current intensity measured by a current measuring device in the first embodiment of the present invention listed above, or the current intensity measured by at least one of the two current measuring devices in the alternative embodiment of the present invention listed above, exceeds at least one predetermined limit value. Accordingly, in the present method for activation, for example, if the current intensity measured by a current measuring device in the first embodiment of the present invention listed above, or the current intensity measured by at least one of the two current measuring devices in the alternative embodiment of the present invention listed above, exceeds at least one predetermined limit value, the processing unit activates the contactor and / or at least one isolator for isolation. This further instructs the electric vehicle battery to open its contactor and / or activate one or more isolators to block the short-circuit current, in addition to the aforementioned switching off of one or more DC-DC converters, in order to eliminate the short-circuit current. The isolators, or each isolator, are configured as, for example, semiconductor switches, diodes, or explosive fuses, i.e., pyro-fuses, which are pyro-technical isolators. At this early stage, the current is low in a low-resistance varistor compared to a conductive insulating short circuit in a DC charging station, so one or more isolators, and for example the contactor of an electric vehicle battery, can be made smaller because no design for short-circuit current is required.

[0016] Therefore, the solution according to the present invention allows for rapid and interference-free identification, via current measurement, of a high-voltage potential exceeding a specified value in the vehicle's high-voltage onboard electrical system, thereby enabling the early shutdown of one or more DC-DC converters. This prevents the varistor or insulation in the DC charging station from being overloaded by the overvoltage, because the voltage is limited to a value below the insulation design voltage by the varistor in the high-voltage onboard electrical system. Furthermore, this prevents damage or destruction of the varistor and ground potential wire of the charging cable by the high current, as the resulting high-voltage onboard electrical system short-circuit current is held within the vehicle by the varistor in the high-voltage onboard electrical system. Moreover, unlike other solutions, the solution according to the present invention achieves fault identification without interference, thus avoiding faulty charging interruptions. Furthermore, the relatively low trigger voltage of the varistor in the high-voltage onboard electrical system allows for more rapid identification of the resulting fault, as the resulting battery current is still limited by the varistor's resistance. This eliminates the need to design for high short-circuit currents, enabling the use of smaller isolators and / or contactors for interruption.

[0017] In summary, the above solution allows for the rapid implementation of safety measures via a low-resistance varistor in the event of an insulation failure, based on an evaluation of the current measurement and a comparison of the current intensity with one or more predetermined limit values, particularly enabling the early switching off of one or more DC-DC converters and, for example, the early opening of contactors and / or isolators at already low current levels.

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Brief explanation of the drawing]

[0019] [Figure 1]Schematic diagram of an embodiment of a high-voltage in-vehicle electrical system of a vehicle that is electrically connected to a DC charging station via a charging cable.

Embodiments for Carrying Out the Invention

[0020] FIG. 1 shows a schematic diagram of a high-voltage in-vehicle electrical system 3 of a vehicle 4 that is electrically connected to a DC charging station 2 via a charging cable 1.

[0021] The vehicle 4 is particularly an electric vehicle or a hybrid vehicle. That is, the vehicle 4 has at least one electrical drive unit for its own drive. For the electrical energy supply of this at least one electrical drive unit, the high-voltage in-vehicle electrical system 3 has an electric vehicle battery 5.

[0022] The high-voltage in-vehicle electrical system 3 further has a charging terminal 6 for electrically connecting to a DC charging station 2 outside the vehicle. This connection is made via the charging cable 1. For this purpose, the charging cable 1 is electrically connected to or is electrically connected with the DC charging station 2 and the charging terminal 6.

[0023] The high-voltage in-vehicle electrical system 3 further has a high-voltage positive potential line HV+L, a high-voltage negative potential line HV-L, and a reference potential line ML, particularly a ground potential line. This also applies to the charging cable 1 and the DC charging station 2 as shown in FIG. 1.

[0024] Furthermore, in the high-voltage in-vehicle electrical system 3, particularly, an insulation resistance Riso+BN between the high-voltage positive potential line HV+L and the reference potential line ML, an insulation resistance Riso-BN between the high-voltage negative potential line HV-L and the reference potential line ML, a Y capacitor C+BN between the high-voltage positive potential line HV+L and the reference potential line ML, and a Y capacitor C-BN between the high-voltage negative potential line HV-L and the reference potential line ML are provided.

[0025] Similarly, the DC charging station 2 is provided with, in particular, an insulation resistor Riso+LS between the high-voltage positive potential line HV+L and the reference potential line ML, an insulation resistor Riso-LS between the high-voltage negative potential line HV-L and the reference potential line ML, a Y capacitor C+LS between the high-voltage positive potential line HV+L and the reference potential line ML, and a Y capacitor C-LS between the high-voltage negative potential line HV-L and the reference potential line ML.

[0026] The high-voltage on-board electrical system 3 is configured to charge the electric vehicle battery 5 at a charging voltage lower than the battery voltage of the electric vehicle battery 5 at the DC charging station 2. For example, the DC charging station 2 is configured to charge an 800V electric vehicle battery at a charging voltage of 400V or 500V. For example, the electric vehicle battery 5 is intended to have a battery voltage of 800V, and the DC charging station 2 has a charging voltage of 500V, also known as the design voltage. To achieve the above-mentioned charging of the electric vehicle battery 5, the high-voltage on-board electrical system 3 has a DC-DC converter 7, which in the illustrated embodiment is located on the high-voltage positive potential line HV+L of the high-voltage on-board electrical system 3. The DC-DC converter 7 is configured as a galvanically coupled DC-DC converter 7.

[0027] However, a problem arises when an insulation failure occurs in vehicle 4, as a direct consequence, another insulation failure may occur at the opposite high potential on the DC charging station 2 side. Many DC charging station manufacturers install a varistor (not shown here) between the reference potential and the high-voltage positive potential or between the reference potential and the high-voltage negative potential in DC charging station 2 to protect the insulation. This varistor in DC charging station 2 has a terminal voltage of, for example, 500V to 550V. If this varistor in DC charging station 2 activates or the insulation fails, the electric vehicle battery 5 will short-circuit. This short-circuit, in the so-called CHAdeMO charging standard, results in the destruction of the ground potential wire, i.e., the reference potential wire ML, in charging cable 1, because this ground potential wire is very fine. Currently, the limit values ​​are 100mAs to protect the varistor in DC charging station 2 and 7000As to protect the ground potential wire in charging cable 1. 2 is defined

[0028] In Figure 1, the first arrow P1 indicates the normal charging current flow during charging of the electric vehicle battery 5. Furthermore, in Figure 1, the previously described fault cases are represented by the fault symbol FS. In the illustrated example, as shown by the connecting wire passing through the insulation resistor Riso+BN, an insulation fault in the vehicle 4 causes a conductive connection between the high voltage potential and the reference potential. As a result, the second arrow P2 indicates the short-circuit current flowing through the high-voltage on-board electrical system 3.

[0029] To solve the above-mentioned problems, in the illustrated embodiment, a series circuit consisting of a varistor 8 and a current measuring device 9 is arranged between the high-voltage negative potential line HV-L and the reference potential line ML.

[0030] In alternative embodiments not shown, the DC-DC converter 7 is located on the high-voltage negative potential line HV-L of the high-voltage onboard electrical system 3 and is similarly configured as a galvanically coupled DC-DC converter 7. In this case, a series circuit consisting of a varistor 8 and a current measuring device 9 is located between the high-voltage positive potential line HV+L and the reference potential line ML. Accordingly, a corresponding fault case can be detected in which the high-voltage negative potential and the reference potential become conductively connected due to an insulation fault in the vehicle 4.

[0031] Furthermore, in both the illustrated embodiment and other embodiments not shown, a processing unit 10 connected to the current measuring device 9 and the DC-DC converter 7 is provided. This processing unit 10 is designed and configured to switch off the DC-DC converter 7 when the current intensity measured by the current measuring device 9 exceeds at least one predetermined limit value.

[0032] In a method for operating the high-voltage on-board electrical system 3 of the vehicle 4, a current measuring device 9 is evaluated by the processing unit 10, and if the current intensity measured by the current measuring device 9 exceeds at least one predetermined limit value, the DC-DC converter 7 is switched off.

[0033] The above-mentioned problem is solved using the previously described embodiment of the high-voltage onboard electrical system 3 by having the varistor 8 of the vehicle 4's high-voltage onboard electrical system 3 first transition to a low-resistance state when an insulation failure occurs in the vehicle 4, which could potentially expose the insulation on the DC charging station 2 side to an excessively high applied voltage. To ensure this, the varistor 8 is configured to transition to a low-resistance state when it exceeds a predetermined voltage lower than, for example, the design voltage of the DC charging station 2 outside the vehicle, for example, 500V. Thus, this predetermined voltage is, for example, 450V. In addition, the varistor 8 has a corresponding characteristic curve. Therefore, the varistor 8 transitions to a low-resistance state before exceeding the design voltage of the DC charging station 2.

[0034] The current measurement device 9 can be used to quickly and without interference measure the generated conductive path. Through evaluation using the processing unit 10, the measured current, i.e., the current intensity of that current, is compared with at least one predetermined limit value or a plurality of predetermined limit values, and when necessary, i.e., when the limit value is exceeded, the DC-DC converter 7 is switched off very quickly. In other words, the function of the DC-DC converter 7 is stopped.

[0035] Additionally, for example, the processing unit 10 can be connected to a contactor (not shown) of the electric vehicle battery 5, and / or to an isolator 11 located on at least one of the high-voltage potential lines HV+L, HV-L of the high-voltage onboard electrical system 3. In this case, the processing unit is designed and configured to activate the contactor and / or at least one isolator 11 for isolation when the current intensity measured by the current measuring device 9 exceeds at least one predetermined limit value. Accordingly, in this method for operation, for example, the processing unit 10 activates the contactor and / or at least one isolator 11 for isolation when the current intensity measured by the current measuring device 9 exceeds at least one predetermined limit value. This further instructs the electric vehicle battery 5 to open its contactor and / or activate one or more isolators 11 to block the short-circuit current, in addition to the aforementioned switch-off of the DC-DC converter 7, in order to eliminate the short-circuit current. The isolator 11, or each isolator 11, is configured as a diode, a semiconductor switch, or a burst fuse, for example, as shown in the illustrated example. At this early stage, the current in the low-resistance varistor 8 is lower than that of a conductive insulating short circuit in the DC charging station 2, so one or more isolators 11, and for example the contactor of the electric vehicle battery 5, can be made smaller because there is no need to design for short-circuit current.

[0036] In another embodiment not shown, one DC-DC converter 7 of the high-voltage on-board electrical system 3 is placed on each of the high-voltage positive potential line HV+L and the high-voltage negative potential line HV-L, and is similarly configured as a galvanically coupled DC-DC converter 7. Correspondingly, a series circuit consisting of a varistor 8 and a current measuring device 9 is placed between each of the high-voltage potential lines HV+L, HV-L and the reference potential line ML. Here, it is possible to detect a fault case in which the high-voltage positive potential and the reference potential become conductively connected due to an insulation fault in the vehicle 4, and it is also possible to detect a fault case in which the high-voltage negative potential and the reference potential become conductively connected due to an insulation fault in the vehicle 4.

[0037] In this embodiment, a processing unit 10 is provided that is connected to each current measuring device 9 and DC-DC converter 7. This processing unit 10 is designed and configured to switch off the DC-DC converter 7 when the current intensity measured by at least one of the current measuring devices 9 exceeds at least one predetermined limit value.

[0038] In a method for operating the high-voltage on-board electrical system 3 of the vehicle 4, the current measuring device 9 is evaluated by the processing unit 10, and if the current intensity measured by at least one of the current measuring devices 9 exceeds at least one predetermined limit value, the DC-DC converter 7 is switched off.

[0039] The above-mentioned problem is also solved by using this embodiment of the high-voltage onboard electrical system 3, by having the corresponding varistor 8 of the vehicle 4 transition to a low-resistance state first, in the event that insulation failures occur in the vehicle 4, potentially exposing the insulation on the DC charging station 2 side to an excessively high applied voltage. Therefore, in this embodiment, each varistor 8 is configured to transition to a low-resistance state when a predetermined voltage lower than, for example, 500V, is exceeded at the DC charging station 2 outside the vehicle. Thus, this predetermined voltage is, for example, 450V. In addition, each varistor 8 has a corresponding characteristic curve. Therefore, the varistor 8 transitions to a low-resistance state before exceeding the design voltage of the DC charging station 2. Thus, in this embodiment, two varistors 8 are configured in this manner.

[0040] In this embodiment as well, the current path generated can be measured quickly and without problems by measuring the current of the corresponding current measuring device 9. Through evaluation using the processing unit 10, the measured current, i.e., the current intensity of that current, is compared with at least one predetermined limit value or a plurality of predetermined limit values, and when necessary, i.e., when it exceeds the limit value, the DC-DC converter 7 is switched off very quickly. In other words, the function of the DC-DC converter 7 is stopped.

[0041] Additionally, in this embodiment as well, the processing unit 10 can be connected to the contactor of the electric vehicle battery 5 and / or to an isolator 11 located on at least one of the high-voltage potential lines HV+L, HV-L of the high-voltage onboard electrical system 3. In this case, the processing unit is designed and configured to activate the contactor and / or at least one isolator 11 for isolation when the current intensity measured by at least one of the two current measuring devices 9 exceeds at least one predetermined limit value. Accordingly, in this method for operation, for example, the processing unit 10 activates the contactor and / or at least one isolator 11 for isolation when the current intensity measured by at least one of the two current measuring devices 9 exceeds at least one predetermined limit value. This further instructs the electric vehicle battery 5 to open its contactor and / or activate one or more isolators 11 to block the short-circuit current, in addition to the aforementioned switch-off of the DC-DC converter 7, to eliminate the short-circuit current. Here again, the isolator 11 or each isolator 11 can be configured as, for example, a semiconductor switch, a diode, or a burst fuse. At this early stage, the current in the low-resistance varistor 8 is lower than that of the conductive insulating short circuit in the DC charging station 2, so one or more isolators 11, and for example the contactor of the electric vehicle battery 5, can be made smaller because there is no need to design for the short-circuit current. [Explanation of symbols]

[0042] 1 Charging cable 2 DC charging stations 3. High-voltage in-vehicle electrical systems 4 vehicles 5. Batteries for electric vehicles 6 Charging terminal 7 DC-DC Converters 8 Barista 9 Current measuring device 10 processing units 11 Isolators C+BN Y-capacitor for high-voltage automotive electrical systems C-BN Y-capacitor for high-voltage automotive electrical systems Y capacitor for C+LS charging station Y capacitor for C-LS charging station FS Fault Symbol HV+L High Voltage Positive Potential Line HV-L High Voltage Negative Potential Line ML reference potential line P1 First arrow P2 Second arrow Riso+BN Insulation Resistance for High-Voltage Automotive Electrical Systems Riso-BN Insulation Resistance for High-Voltage Automotive Electrical Systems Insulation resistance of Riso+LS charging station Insulation resistance of Riso-LS charging station

Claims

1. A vehicle (4) equipped with a high-voltage on-board electrical system (3), The aforementioned high-voltage in-vehicle electrical system (3) Battery for electric vehicles (5) and A charging terminal (6) for electrically connecting to an external DC charging station (2) of the vehicle, High voltage positive potential line (HV + L), High-voltage negative potential line (HV-L) and, Reference potential line (ML), Having, In the aforementioned vehicle (4), A DC-DC converter (7) is positioned on one of the high-voltage potential lines (HV+L, HV-L), and a series circuit consisting of a varistor (8) and a current measuring device (9) is positioned between the other high-voltage potential line (HV-L, HV+L) and the reference potential line (ML). A processing unit (10) is provided that is connected to the current measuring device (9) and the DC-DC converter (7), and the processing unit (10) is designed and configured to stop the function of the DC-DC converter (7) by switching off the DC-DC converter (7) when the current intensity measured by the current measuring device (9) exceeds at least one predetermined limit value, or DC-DC converters (7) are arranged on each of the two high-voltage potential lines (HV+L, HV-L), and a series circuit consisting of a varistor (8) and a current measuring device (9) is arranged between each of the high-voltage potential lines (HV+L, HV-L) and the reference potential line (ML). A processing unit (10) is provided that is connected to each of the current measuring devices (9) and the DC-DC converter (7), and the processing unit (10) is designed and configured to stop the function of the DC-DC converter (7) by switching off the DC-DC converter (7) when the current intensity measured by at least one of the current measuring devices (9) exceeds at least one predetermined limit value. The vehicle (4) characterized by the above.

2. The vehicle (4) according to claim 1, characterized in that the varistor (8), or each of the varistors (8), is configured to transition to a low-resistance state when it exceeds a predetermined voltage lower than the design voltage of the DC charging station (2) located outside the vehicle, which is electrically connected to the charging terminal (6).

3. The vehicle (4) according to claim 1 or 2, characterized in that the DC-DC converter (7), or each of the DC-DC converters (7), is configured as a galvanically coupled DC-DC converter (7).

4. The vehicle (4) according to claim 1 or 2, wherein the processing unit (10) is connected to a contactor of the electric vehicle battery (5) and / or to an isolator (11) located on at least one of the high-voltage potential lines (HV+L, HV-L), and is designed and configured to activate the contactor and / or at least one of the isolators (11) for isolation when the current intensity measured by the current measuring device (9), or the current intensity measured by at least one of the two current measuring devices (9), exceeds at least one predetermined limit value.

5. The vehicle (4) according to claim 4, characterized in that the isolator (11) is configured as a semiconductor switch, a diode, or an explosive fuse.

6. A method for operating a high-voltage on-board electrical system (3) of a vehicle (4) according to claim 1 or 2, The current measuring device (9) is evaluated by the processing unit (10), and if the current intensity measured by the current measuring device (9) exceeds at least one predetermined limit value, the DC-DC converter (7) is switched off, or The method is characterized in that the current measuring device (9) is evaluated by the processing unit (10), and if the current intensity measured by at least one of the current measuring devices (9) exceeds at least one predetermined limit value, the DC-DC converter (7) is switched off.

7. The method according to claim 6, characterized in that the processing unit (10) activates a contactor and / or at least one isolator (11) for separation when the current intensity measured by the current measuring device (9), or the current intensity measured by at least one of the two current measuring devices (9), exceeds at least one predetermined limit value.

Images