High-voltage electrical system for a vehicle

Abstract

The high-voltage electrical system (HV-BN) comprises a charging terminal (CP), a charging device (OBC), a high-voltage battery (HV-BAT), a connection assembly, and a grounding device (DS). The grounding device (DS) includes an EMC filter and a grounding path with a controllable grounding isolator (IS_DS). A first cylindrical capacitor (CY1) of the EMC filter is connected to a connection path (L1) that carries a first high-voltage potential (HV+) from the charging terminal (CP) to the HV battery (HV-BAT). A second cylindrical capacitor (CY2) of the EMC filter is connected to a connection path (L2) that carries a second high-voltage potential (HV+) from the charging terminal (CP) to the HV battery (HV-BAT). The first Cy capacitor (CY1) and the second Cy capacitor (CY2) are connected in series via a connection node (V). The leakage isolation device (IS_DS) is located in the leakage path, and the leakage path connects the connection node (V) to a reference potential of the vehicle.The discharge isolation device (IS_DS) is controlled depending on a charging mode.

Description

[0001] The invention relates to a high-voltage electrical system, HV electrical system, for a vehicle.

[0002] High-voltage electrical systems for electric vehicles, especially for purely electric vehicles, incorporate EMC filtering devices to comply with EMC requirements during DC charging. This means that sufficient interference suppression is not relied upon at the charging station itself.

[0003] Such an EMC filter device is, for example, located in a DC charging current path that connects a vehicle charging port to a traction battery. However, during a charging process that does not have complete galvanic isolation, or generally in the case of faulty insulation or grounding during charging, these EMC filter devices can cause a voltage to exist between the vehicle's ground or chassis potential and the ground potential of the charging current source, which can be dangerous for a person.

[0004] It is therefore an object of the invention to provide a high-voltage electrical system for a vehicle that contributes to improving the high-voltage safety of the high-voltage electrical system, which has a charging port for DC charging and AC charging.

[0005] The problem is solved by the features of the independent patent claims. Advantageous embodiments are characterized in the dependent claims.

[0006] The problem is solved by a high-voltage electrical system (HV electrical system) for a vehicle, comprising a charging port, an AC charging device (charging device), a high-voltage battery (HV battery), a connection arrangement and a discharge device with an EMC filter.

[0007] The charging port is designed to electrically connect the high-voltage vehicle electrical system to an external power source. Preferably, the charging port is designed for both AC and DC charging. Therefore, either an AC or a DC charging source can be connected to the charging port.

[0008] The connection arrangement comprises a plurality of connection paths, each having a controllable isolating device, and is configured to electrically connect the charging port to the charging device and the charging device to the high-voltage battery in an AC charging mode of the high-voltage electrical system, and to connect the charging port to the high-voltage battery in a DC charging mode of the high-voltage electrical system. Preferably, in the DC charging mode, the connection arrangement is configured to connect the charging port directly to a first terminal of the EMC filter without intermediate isolating devices, and to connect a second terminal of the EMC filter to the high-voltage battery via intermediate controllable isolating devices. The controllable isolating devices preferably each comprise a controllable contactor or a controllable relay.If the connection paths are DC high-voltage paths, the isolation devices preferably comprise controllable contactors. If, on the other hand, they are AC transmission paths, the isolation devices preferably each comprise a controllable relay.

[0009] The discharge device comprises the EMC filter and a discharge path in which a controllable discharge isolation device is arranged.

[0010] The isolation device includes, for example, a switch, in particular a bidirectional blocking semiconductor switch.

[0011] The EMC filter features a first Cy capacitor and a second Cy capacitor. Cy capacitors are capacitors that divert an interference signal of a DC voltage potential to a reference potential such as ground, whereby the DC voltage potential is electrically isolated from the ground potential.

[0012] The first Cy capacitor is arranged in a first branch, the first terminal of which is connected to one of the connection paths of the connection arrangement, which is configured to carry a first high-voltage potential from the charging terminal to the HV battery. The second Cy capacitor is arranged in a second branch, the first terminal of which is connected to one of the connection paths of the connection arrangement, which is configured to carry a second high-voltage potential from the charging terminal to the HV battery. The first and second branches are connected in series via a connection node.

[0013] The leakage disconnect device is located in the leakage path, and the leakage path connects the connection node to a reference potential of the vehicle, in particular to a ground potential or chassis potential of the vehicle. The leakage path thus forms a switchable connection between the connection node and the vehicle's ground potential. This allows the connection of the respective Cy capacitors to ground potential to be disconnected, thereby suppressing the flow of any touch voltage.

[0014] A filter element, a fuse or a current limiting resistor may be arranged in the leakage path, or the leakage path may be provided as a direct (switchable) connection.

[0015] The discharge device has a control unit, or a control unit is associated with the discharge device. The control unit is configured to detect a DC charging mode and, if a DC charging mode is detected, to directly or indirectly control the discharge disconnect device during the DC charging mode so that the discharge disconnect device is in a closed state, and if no DC charging mode is detected, to directly or indirectly control the discharge disconnect device so that it is in an open state. The control unit may be part of a control unit of the high-voltage electrical system or another higher-level control unit.

[0016] The high-voltage electrical system's discharge device ensures that, in a vehicle using a single charging input for both DC and AC charging, the EMC filter can provide sufficient interference suppression during DC battery charging. Opening the discharge isolator before AC charging eliminates any touch current contribution from the Y-capacitor of the DC charging EMC filter when the protective conductor is interrupted. This allows for simple and cost-effective compliance with the touch current thresholds according to ISO 5474-2 for the bidirectional on-board charger (BOBC).

[0017] The discharge device, in conjunction with the special control of the discharge isolation device, can be used particularly advantageously when the EMC filter is located directly at the charging port, i.e., without the interposition of further components and / or with short cable lengths. In this case, the filtering effect and thus the interference suppression are optimal. The discharge isolation device ensures that the required high-voltage safety with regard to touch protection at the charging port can still be maintained, especially if, for example, an interruption of the protective conductor occurs, such as due to improper installation of an AC charging socket. The connection node can be selectively isolated from the ground potential, for example during AC charging, in order to prevent a dangerous touch current in the event of faulty insulation or grounding of the charging current source.

[0018] The connection arrangement preferably includes a further control unit, or a further control unit is assigned to the connection arrangement, which is configured to control the respective isolating devices depending on an operating mode of the high-voltage electrical system. The control unit of the isolating device and the further control unit of the connection arrangement can be formed by a single control unit or be different control units.

[0019] In at least one advantageous embodiment, the control unit is configured to receive a measurement signal or measurement data that is / are representative of a voltage at the charging port, and to detect a DC charging operating mode depending on the received measurement signal or measurement data.

[0020] In at least one advantageous embodiment, the control unit is configured to receive a communication signal or communication data which includes information that an energy source providing a DC charging voltage is connected to the charging port.

[0021] In at least one advantageous embodiment, the control unit is designed to control the discharge isolation device in such a way that the discharge isolation device has an open state within a predetermined time period after the end of the DC charging mode, wherein the predetermined time period is less than five seconds or two seconds or one second.

[0022] In at least one advantageous embodiment, an ohmic resistor and / or a fuse and / or a filter element is arranged in the first branch and / or the second branch to limit a flowing current.

[0023] In at least one advantageous embodiment, the EMC filter comprises at least one further first Cy capacitor and at least one further second Cy capacitor. The at least one further first Cy capacitor is arranged in a further first branch, the first terminal of which is connected to the connection path configured to carry the first high-voltage potential from the charging terminal to the HV battery. The at least one further second Cy capacitor is arranged in a further second branch, the first terminal of which is connected to the connection path configured to carry the second high-voltage potential from the charging terminal to the HV battery. The at least one further first branch and the at least one further second branch are each connected in series via the connection node.

[0024] The Cy capacitors of the EMC filter are preferably dedicated filter components, but can also be configured as parasitic capacitors. The Cy capacitors can be configured as individual capacitor components or as a capacitor circuit.

[0025] In at least one advantageous embodiment, the charging device is bidirectional. The device is thus further configured to convert a DC voltage supplied by the HV battery into an AC voltage. The charging port is designed to be connected to an external load. The connection arrangement is designed to electrically connect the charging port to the charging device and the charging device to the HV battery in a regenerative operating mode of the high-voltage electrical system, in which energy is transferred from the HV battery to the external load. In this application in particular, the grounding device enables compliance with specified high-voltage safety requirements, e.g., according to ISO 5474-2, for protection against electric shock, even in a regenerative operating mode of the HV electrical system.

[0026] In at least one advantageous embodiment, the EMC filter is directly connected to the charging port.

[0027] Exemplary embodiments of the invention are explained in more detail below with reference to the schematic drawings. The description of the items mentioned here is not limited to the individual specific embodiments. Features of different exemplary embodiments can be combined with one another—where technically feasible—to form further exemplary embodiments. For example, variations or modifications described with regard to one of the exemplary embodiments may also be applicable to other exemplary embodiments, unless otherwise stated. Fig. Figure 1 shows an exemplary block diagram of an embodiment of a high-voltage electrical system (HV electrical system) for a vehicle, Fig. Figure 2 shows an exemplary equivalent circuit diagram of another embodiment of a leakage device and Fig. Figure 3 shows an exemplary block diagram of another embodiment of an HV electrical system.

[0028] In the figures, the same reference symbols are used for elements with essentially the same function; however, these elements do not have to be identical in every detail.

[0029] It should be noted that when an element is described as "connected" or "coupled" to another element, the element may be directly connected or coupled to the other element, or intermediate elements may be present. Conversely, when an element is described as "directly" "connected" or "coupled" to another element, no intermediate elements are present. Other expressions used to describe the relationship between elements should be interpreted similarly (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.).

[0030] Fig. Figure 1 shows an exemplary block diagram of an embodiment of a high-voltage electrical system (HV electrical system) HV-BN for a vehicle and an external energy source SE connected to the HV electrical system HV-BN.

[0031] An electric vehicle is preferably a purely battery-powered vehicle (Battery Electric Vehicle, BEV) that uses an electric motor as its sole source of propulsion. The term "electric vehicle" here refers not only to motor vehicles but to all electrically powered vehicles, such as industrial trucks or forklifts.

[0032] The HV-BN electrical system comprises a charging port CP, a charging device OBC, a discharge device DS, a high-voltage battery (HV battery) HV-BAT, and a connection assembly. The connection assembly includes a first high-voltage connection, an AC connection, and a second high-voltage connection.

[0033] The external energy source (SE) is, for example, an external vehicle charging station or charging point. However, the external energy source (SE) can also be a mobile energy source, such as another electric vehicle.

[0034] The external power source SE is configured to supply electricity to the electric vehicle. Specifically, the external power source SE is configured to provide at least one AC charging mode and / or at least one DC charging mode. In AC charging mode, the external power source SE provides an alternating current which is converted into a corresponding DC charging current by the electric vehicle's charging device, also known as the on-board charger (OBC).

[0035] In at least one DC charging mode, the external power source SE provides a direct current. In this DC charging mode, the external power source SE is specifically designed to set and maintain charging parameters, particularly charging current and voltage, as required or desired for charging the connected vehicle. The corresponding external power source SE is then responsible for maintaining these charging parameters.

[0036] The external power source SE is, for example, designed to perform AC charging and / or DC charging in accordance with the North American Charging Standard (SAE J3400). This means that the external power source SE is designed to meet the general physical, electrical, functional, safety, and performance requirements of the North American Charging Standard (SAE J3400) for conductive power transfer to the electric vehicle using a hand-connected plug, and to transmit either DC or single-phase AC using two live contacts.

[0037] The charging port CP of the HV-BN electrical system comprises a first charging port CP1 and a second charging port CP2. The HV-BAT battery has a first battery connection A1 and a second battery connection A2. The OBC charging device comprises a first AC connection AC1 and a second AC connection AC2. Furthermore, the OBC charging device comprises a first DC connection DC1 and a second DC connection DC2.

[0038] The discharge device DS includes an EMC filter (electromagnetic compatibility filter). The first high-voltage connection connects the charging port CP to the high-voltage battery HV-BAT via the EMC filter. This first high-voltage connection has a first connection path L1, which connects the first charging port CP1 to the first battery terminal A1. The first connection path L1 is configured to carry a first high-voltage potential HV+ from the charging port CP, specifically from the first charging port CP1, to the high-voltage battery HV-BAT. Furthermore, the first high-voltage connection has a second connection path L2, which connects the second charging port CP2 to the second battery terminal A2. The second connection path L2 is configured to carry a second high-voltage potential HV- from the charging port CP, specifically from the second charging port CP2, to the high-voltage battery HV-BAT.

[0039] In the first connection path L1, for example, a controllable first disconnect device IS1 and a controllable third disconnect device IS3 are arranged. In the second connection path L2, for example, a controllable second disconnect device IS2 and a controllable fourth disconnect device IS4 are arranged.

[0040] The first and second disconnect devices IS1 and IS2, for example, are the DC charging contactors of the high-voltage electrical system HV-BN, which are closed when the high-voltage electrical system HV-BN is connected to, for example, an external DC charging source. This allows the charging terminal CP to be connected to the high-voltage battery HV-BAT on all poles and to be disconnected from the high-voltage battery HV-BAT on all poles.

[0041] The third and fourth disconnect devices, IS3 and IS4, are, for example, the high-voltage battery contactors. These contactors are used for disconnecting / connecting, in particular for the all-pole disconnection / connection of the high-voltage battery HV-BAT from / to the high-voltage electrical system HV-BN, especially from / to the loads (motor and / or high-voltage auxiliary units HV-AUX) of the HV-BN electrical system. This makes it possible to disconnect the high-voltage battery HV-BAT all-pole from all consumers of the HV-BN electrical system, the charging device OBC, and the charging port CP.

[0042] The EMC filter of the leakage device comprises at least one first Cy capacitor CY1 and at least one second Cy capacitor CY2. Furthermore, the leakage device DS includes a controllable leakage isolation device DS_IS.

[0043] Fig. Figure 1 shows an embodiment of the discharge device DS, in which the EMC filter has only one first and one second Cy capacitor CY1, CY2. The first Cy capacitor CY1 is arranged in a first branch, with a first terminal of the first branch connected to the first connection path L1 and a second terminal of the first branch connected to a connection node V, which is connected to a first terminal of the discharge isolator DS_IS.

[0044] The second Cy capacitor CY2 is arranged in a second branch, with a first terminal of the second branch connected to the second connection path L2. A second terminal of the second branch is also connected to the connection node V, which is connected to the first terminal of the leakage isolator DS_IS.

[0045] A second connection of the DS_IS disconnect device is connected to a reference potential of the electric vehicle, preferably to a ground potential or chassis potential of the vehicle.

[0046] Current limiting elements may be arranged in the first and / or second branch. The EMC filter may have a plurality of first Cy capacitors Cy1, Cy1a and second Cy capacitors Cy2, Cy2a. The EMC filter may also include further filter components, for example, inductive filter components Ind, and / or be multi-stage.

[0047] Fig. Figure 2 shows an exemplary equivalent circuit diagram of another embodiment of the DS leakage device. In this case, the EMC filter has at least one additional first Cy capacitor Cy1a. The additional first Cy capacitors Cy1a are each arranged in a further first branch. These additional first branches are, for example, each connected at their first terminal to the first connection path L1 and at their second terminal to the connection node V.

[0048] Furthermore, the EMC filter has at least one additional second Cy capacitor, Cy2a. These additional second Cy capacitors, Cy2a, are each arranged in a further second branch. These further second branches are each connected, for example, with their first terminal to the second connection path L2 and with their second terminal to the connection node V.

[0049] The EMC filter in Fig. For example, 2 has a ferrite ring core as the inductive element Ind, through which the first connection path L1 and the second connection path L2 are passed.

[0050] Current limiting elements can be arranged in the first and second branches. In the Fig. In the embodiment shown in 2, the further first branches and the further second branches comprise an ohmic resistance.

[0051] The DS_IS isolating device is designed, for example, as a semiconductor switch. Specifically, the DS_IS is designed as a bidirectional blocking semiconductor switch. This can be achieved either by using a single bidirectional blocking transistor element or by using two transistor elements connected in anti-series. "Anti-series" in this context means that the forward bias directions of the two transistor elements are opposite to each other and that the two transistor elements are connected in series. The semiconductor switch can therefore have two transistor elements connected in series, which are specifically designed as MOSFETs. The transistor elements are oriented in opposite directions to each other. The two series-connected transistor elements each have an inverse diode. The forward bias directions of the inverse diodes are opposite to each other.In this way, when transistor elements are open, one of the transistor elements always blocks the current flow across the entire semiconductor switch.

[0052] Alternatively, the leakage disconnect device can include a relay.

[0053] The OBC charging device ( Fig. 1) The charging device OBC includes a voltage converter, which in particular comprises a filter for smoothing an alternating voltage and a power factor correction (PFC) filter. The voltage converter can be supplied with the alternating voltage. Furthermore, the OBC charging device includes, for example, a first DC / DC converter and a second DC / DC converter. The two DC / DC converters are designed to be insulated. The voltage converter and the DC / DC converters are bidirectional. This means that the OBC charging device is designed to receive energy from the external energy source SE and forward at least part of it to the high-voltage battery HV-BAT, and also to receive energy from the high-voltage battery HV-BAT and forward at least part of it to an external load connected to the charging terminal CP.

[0054] The AC connection of the connection arrangement comprises a first AC connection path AC-L1 and a second AC connection path AC-L2. The first AC connection path AC-L1 connects the first charging terminal CP1 to the first AC terminal AC1 of the charging device OBC. The second AC connection path AC-L2 connects the second charging terminal CP2 to the second AC terminal AC2 of the charging device OBC. A controllable disconnect device IS5, IS6 is preferably arranged in each of the first and second AC connection paths AC-L1, AC-L2. These controllable disconnect devices IS5, IS6 can each comprise a relay or be formed by a relay.

[0055] A first connection node K1 is arranged between the first isolating device IS1 and the third isolating device IS3, and the third connection path L3 is connected to the first connection path L1 via the first connection node K1. Furthermore, a second connection node K2 is arranged between the second isolating device IS2 and the fourth isolating device IS4, and the fourth connection path L4 is connected to the second connection path L2 via a second connection node K2.

[0056] The second high-voltage connection connects the DC terminal of the charging device OBC to the first and second connection nodes K1 and K2. Specifically, the third high-voltage path L3 connects the first DC terminal DC1 of the charging device OBC to the first connection node K1, and the fourth high-voltage path L4 connects the second DC terminal DC2 to the second connection node K2.

[0057] In the case of the controllable disconnect devices IS1, ... IS6 and the controllable grounding disconnect device DS_IS, one switching state in particular is controllable. The switching state of the grounding disconnect device DS_IS is controlled by a first control unit (not shown in Fig. 1) controlled. For this purpose, the discharge device DS can have the first control unit. Alternatively, the first control unit can be assigned to the discharge device DS and / or be part of a higher-level second control unit.

[0058] The first control unit is designed to detect a DC charging mode and, if a DC charging mode is detected, to directly or indirectly control the DS_IS isolating device during the DC charging mode such that the DS_IS isolating device is in a closed state, and if no DC charging mode is detected, to directly or indirectly control the DS_IS isolating device such that the IS_DS is in an open state.

[0059] The first control unit is specifically designed to control the DS_IS isolating device such that the DS_IS isolating device is in an open state within a predetermined time period after the DC charging mode has ended, where the predetermined time period is less than five seconds, two seconds, or one second. For this purpose, one or more outputs of the first control unit can be connected directly or indirectly to the DS_IS isolating device, for example, via circuit drivers.

[0060] The first control unit is specifically configured to receive a measurement signal or measurement data from a voltage sensor V_sens, which is configured to measure a voltage between the first connection path L1 and the second connection path L2. Depending on the received measurement signal or measurement data, the first control unit is configured to detect a DC charging operating mode.

[0061] Alternatively or additionally, the first control unit is configured to receive a communication signal or communication data from a charging port controller (CPC). This communication signal or data includes information indicating that an external energy source (SE) is connected to the charging port (CP) and that the external energy source (SE) is providing a DC charging voltage.

[0062] The connection arrangement preferably comprises a further control unit, or a further control unit is assigned to the connection arrangement, which is configured to control the respective isolating devices IS1, ..., IS6 of the connection arrangement depending on an operating mode of the HV-BN electrical system. The first control unit and the further control unit can be formed by one control unit or be different control units.

[0063] A high-voltage nominal voltage is provided between the first connection path L1 and the second connection path L2, and between the third connection path L3 and the fourth connection path. This voltage is preferably more than 60 volts and preferably at least 200 volts, 400 volts, or 800 volts. Furthermore, within the respective high-voltage electrical system HV-BN, insulation is provided between the two high-voltage potentials HV+ and HV- on the one hand, and the ground potential connection on the other. The high-voltage electrical system HV-BN may also provide a grounding connection PE for connection to a ground potential or may itself be a ground potential. The ground potential belongs, in particular, to an external energy source, for example, the ground potential of a local or public power grid.

[0064] Fig. Figure 3 shows an exemplary block diagram of another embodiment of a high-voltage electrical system (HV-BN) of an electric vehicle.

[0065] The HV-Bordz HV-BN points analogously to the one in Fig. The high-voltage electrical system HV-BN shown in Figure 1 includes a charging port CP, a charging device OBC, a high-voltage battery HV-BAT, and a discharge device DS. This is shown in Figure 1. Fig. The 3-way HV-Bordz (HV-BN) shown differs from the one in Fig. 1 shown HV-Bordz HV-BN in particular by a differently designed connection arrangement.

[0066] The in Fig. The HV-BAT battery shown in Figure 3 is, for example, designed as a switchable HV battery. The HV-BAT battery in Fig. 3 preferably comprises at least two accumulator modules which can be connected in series and in parallel with each other and thus a plurality of operating states of the HV accumulator HV-BAT can be produced, for example an 800-volt charging mode and a 400-volt charging mode and / or 400-volt driving mode and / or an 800-volt driving mode.

[0067] Unlike the one in Fig. The connection arrangement shown in 1 is in the connection arrangement according to Fig. 3 the third disconnection device IS3 in the third high-voltage pad L3 and the fourth disconnection device IS4 in the fourth high-voltage path L4.

[0068] The HV-BAT battery, for example, can have fuses (melt fuses or pyrofus). Reference symbol list A1, A2 first and second accumulator connection point AC1, AC2 first and second AC connection point of the charging device AC-L1 first AC connection path AC-L2 second AC connection path CP charging port CP1, CP2 first and second charging point CPC charging port controller CPD charging port flap Cy1 first and second Cy capacitor Cy1a, Cy2a further first and second CY capacitor DC1, DC2 first and second DC connection point of the charging device DS discharge device DS_IS isolation device HLD High-Voltage to Low-Voltage DC / DC Converter HV second high-voltage potential HV+ first high-voltage potential HV-AUX High-voltage auxiliary power units HV-BAT High-voltage battery HV-BN high-voltage electrical system Inductive element IS1, ..., IS6 controllable disconnect device K1, K2 first and second connection node L1, L2 first and second connection path L3, L4 third and fourth connecting path OBC charging device PE earthing potential SE Energy source V Connection node V_sens voltage sensor

Claims

[1] High-voltage electrical system, HV electrical system, (HV-BN) for a vehicle, wherein - the HV electrical system (HV-BN) comprises a charging port (CP), a charging device (OBC), a high-voltage battery, HV battery (HV-BAT), a connection assembly and a discharge device (DS), - the charging port (CP) is designed for coupling with an external energy source (SE), - the charging device (OBC) is designed to convert an AC voltage provided by the external power source (SE) into a DC voltage, - the discharge device (DS) comprises an EMC filter and a discharge path with a controllable discharge isolation device (IS_DS), - the connection arrangement comprises a plurality of connection paths (L1, ..., L4, AC-L1, AC-L2), wherein at least some of the connection paths (L1, ..., L4, AC-L1, AC-L2) each have a controllable disconnecting device (IS1; ...., IS6) and the connection arrangement is configured to electrically connect the charging terminal (CP) to the charging device (OBC) and the charging device (OBC) to the HV battery (HV-BAT) in an AC charging mode of the HV electrical system (HV-BN), and to connect the charging terminal (CP) to the HV battery (HV-BAT) via the EMC filter in a DC charging mode of the HV electrical system (HV-BN), - the EMC filter has a first Cy capacitor (CY1) and a second Cy capacitor (CY2), - the first Cy capacitor (CY1) is arranged in a first branch which is connected with its first terminal to one of the connection paths (L1) of the connection arrangement which is configured to carry a first high voltage potential (HV+) from the charging terminal (CP) to the HV accumulator (HV-BAT), - the second Cy capacitor (CY2) is arranged in a second branch, which is connected with its first terminal to one of the connection paths (L2) of the connection arrangement, which is configured to carry a second high-voltage potential (HV+) from the charging terminal (CP) to the HV accumulator (HV-BAT), - the first branch and the second branch are connected in series via a connecting node (V), - the discharge isolation device (IS_DS) is arranged in the discharge path and the discharge path connects the connection node (V) to a reference potential of the vehicle, and wherein the discharge device (DS) has a control unit or a control unit is assigned to the discharge device (DS) which is configured to detect a DC charging mode and, if a DC charging mode is detected, to control the discharge isolation device (IS_DS) directly or indirectly during the DC charging mode such that the discharge isolation device (IS_DS) is in a closed state, and, if no DC charging mode is detected, to control the discharge isolation device (IS_DS) directly or indirectly such that the discharge isolation device (IS_DS) is in an open state. [2] High-voltage electrical system (HV-BN) according to claim 1, wherein the control unit is configured to receive a measurement signal or measurement data that is or are representative of a voltage at the charging port (CP), and to detect a DC charging operating mode depending on the received measurement signal or measurement data. [3] High-voltage electrical system (HV-BN) according to claim 1 or 2, wherein the control unit is configured to receive a communication signal or communication data comprising information that an energy source (SE) providing a DC charging voltage is connected to the charging port (CP). [4] High-voltage electrical system (HV-BN) according to one of the preceding claims, wherein the control unit is configured to control the discharge isolation device (IS_DS) such that the discharge isolation device (IS_DS) has an open state within a predetermined time period after the end of the DC charging mode, wherein the predetermined time period is less than five seconds or two seconds or one second. [5] High-voltage electrical system (HV-BN) according to one of the preceding claims, wherein an ohmic resistor and / or a fuse and / or a filter element is arranged in the first branch and / or the second branch. [6] High-voltage electrical system (HV-BN) according to any of the preceding claims, wherein - the EMC filter has at least one further first Cy capacitor (CY1a) and at least one further second Cy capacitor (CY2a), - which at least one further first Cy capacitor (CY1a) is arranged in a further first branch, which is connected with its first terminal to the connection path (L1) which is configured to carry the first high voltage potential (HV+) from the charging terminal (CP) to the HV accumulator (HV-BAT), - which has at least one further second Cy capacitor (CY2a) arranged in a further second branch and connected with its first terminal to the connecting path (L2) which is configured to carry the second high-voltage potential (HV+) to the HV accumulator (HV-BAT), and - each of which at least one further first branch and at least one further second branch are connected in series via the connecting node (V). [7] High-voltage electrical system (HV-BN) according to one of the preceding claims, wherein the charging device (OBC) is bidirectional. [8] High-voltage electrical system (HV-BN) according to one of the preceding claims, wherein the EMC filter is directly connected to the charging port (CP).

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