Vehicle electrical system

Abstract

A vehicle electrical system (FB) is equipped with at least one high-voltage consumer (K, W2), a DC charging terminal (GA), a battery (AK), a rectifier (GR) and a changeover switch (US). The high-voltage consumer (K, W2) is connected to the battery (AK) via the changeover switch (US) in a first switch position (1) of the changeover switch (US) via a first switching device (S1, D) and is connected to the battery (AK) via the changeover switch (US) in a second switch position (2) of the changeover switch (US) via a second switching device (S2, S3), wherein the DC charging terminal (GA) is connected to the battery (AK) via the first switching device (S1, D).

Description

Technical Field

[0001] The invention relates to a vehicle electrical system. Background Art

[0002] Vehicles with an electric drive have a battery which, in the case of plug-in vehicles, can be charged externally by means of a charging terminal. In addition, components with a nominal voltage of, for example, 800 volts are present within the vehicle (e.g., a high-voltage battery), while a different voltage of 400 volts can be set at the charging input, depending on the charging station. Therefore, within the electrical system there are multiple segments which have different nominal voltages but are directly or indirectly connected to the battery. Summary of the invention

[0003] Furthermore, the object of the present invention is to demonstrate a possibility with which a vehicle electrical system can be designed in such a way that, on the one hand, different nominal voltages within the vehicle electrical system are possible and, on the other hand, despite different nominal voltages in segments of the vehicle electrical system, the vehicle can still be charged and driven in a manner that is protected from excessively high contact voltages.

[0004] This task is solved by the vehicle electrical system.

[0005] Further embodiments, features, characteristics and advantages emerge from the further examples, descriptions and figures.

[0006] A vehicle electrical system is proposed, which has at least one high-voltage consumer, a DC charging terminal, a battery and a changeover switch. The changeover switch can be used to set whether the high-voltage consumer is connected to a first path leading to the battery (via a switching device) or whether the high-voltage consumer is connected to a second path leading to the DC charging terminal. As a result, the DC charging terminal can be separated from the first path, so that the filter capacitor (Cy capacitor) in the first path does not act on the DC charging terminal, and the high-voltage consumer is powered both during charging and in driving mode, that is, it is powered by the voltage from the DC charging terminal (when charging) or by the voltage of the battery (in driving mode). An electric drive device can be connected to the first path, which can have a high Cy capacitance, especially for filtering purposes. During DC charging, this path can be separated from the DC charging terminal and from the high-voltage consumer by the changeover switch and by the switching device, while the DC charging terminal and the high-voltage consumer are connected to the battery. As a result, charging can be carried out and voltage can be supplied to the high-voltage consumer at the same time.

[0007] The high-voltage consumer is connected to the battery via the first switching device through the changeover switch in the first switching position of the changeover switch. The high-voltage consumer is connected to the battery via the second switching device through the changeover switch in the second switching position of the changeover switch. In the second switching position, the high-voltage consumer is connected to the first path, which connects the changeover switch to the battery via the second switching device. In the first switching position, the high-voltage consumer is connected to the second path, which connects the changeover switch and the DC charging terminal to the battery via the second switching device. The battery is connected to the connection point. The first and second paths lead from the connection point (in an interruptible or switchable manner, respectively) to the changeover switch. The changeover switch optionally connects one of the two paths and thus one of the two switch units (of the path) to the high-voltage consumer.

[0008] Furthermore, the DC charging terminal can be disconnected from the battery by means of a switching device. The electric drive connected to the battery via a second switching device can also be disconnected from the battery by means of a switch. Thus, the possibility of disconnecting the battery is obtained both for driving and for charging, so that high contact voltages can be avoided. In particular, this operating method allows high voltages stored in the electric drive (for example, the voltage of the intermediate circuit of the electric drive) to be isolated by means of a switching device, so that high contact voltages can be avoided.

[0009] The switching devices are respectively bipolar and comprise a switching element for each of the two potentials (+ and -). The switching devices can thus be separated or connected in an all-polar manner. The switching elements are in particular electromechanical switching elements or otherwise semiconductor switches. The switching elements of the switching devices can be designed as (bipolar) electromechanical switches, for example relays. The switching devices can therefore be implemented by relays. The first and / or second switching devices are preferably designed as double relays.

[0010] One embodiment provides that the first switching unit is provided by a switching unit (at one potential) and a diode (at another potential). The diode conducts in the direction of the charging current of the relevant potential flowing to the battery. The diode can be set at a positive potential. If the diode is at a positive potential, the conduction direction starts from the DC charging terminal and leads to the connection point or the battery. If the diode is at a negative potential or ground potential, the conduction direction is away from the connection point or the battery and points to the DC charging terminal. The diode is preferably a power diode. The diode has the function of a diode, but it does not necessarily have to be realized by a single diode device, but can have other diode devices, or can have other devices that realize the diode function, such as a transistor that is controlled according to the diode function. Therefore, being a diode does not limit a specific component, but indicates the function as a diode or a function like a diode.

[0011] The first switching direction connects two potentials of the DC charging terminal (DC terminal for short) to two potentials of the connection point or the battery. The two potentials are, for example, a negative potential and a positive potential or a positive potential and ground potential. The switching device provides a switching element for one of the potentials. For the other potential, the switching device provides a diode device or another switching element. These are each connected in series.

[0012] The potentials are respectively DC voltage potentials. A DC voltage is applied between the potentials. In particular, each potential corresponds to a (DC) busbar, which can also be referred to as a DC busbar or a DC conductor. A supply voltage, in particular a high-voltage supply voltage, is applied between the potentials. The potentials are in particular high-voltage potentials.

[0013] The second switching device connects the two potentials of the second side of the DC voltage converter to the two potentials of the connection point. In this case, the switching device connects the first potential of the second side to the first potential of the connection point by means of a first switchable connection, and connects the second potential of the second side to the second potential of the connection point by means of a second switchable connection. Thus, the second switching device connects the potentials individually. The switching device has a switching element for each potential. The switching element can be configured as an electromechanical switching element or as a semiconductor switching element, for example, as a transistor. In particular, the two switching elements are formed by contacts of a double relay.

[0014] In addition, it can be provided that the connection point is connected to the battery via a high-temperature fuse device. The high-temperature fuse device is an electrical connection that can be disconnected by means of an explosive. The explosive is triggered by an electric igniter. When triggered, the explosive mechanically separates the electrical connection. As long as the first switching device is equipped with a diode, the high-temperature fuse device is preferably connected in series at the same potential that the diode is also at. The high-temperature fuse device can be designed as a bipolar. A control device can be provided in the sense of a control device, and the control device is set up to operate the switching device or disconnect the switching device according to the open circuit state. The control device is also set up to trigger the high-temperature fuse device only when at least one of the switching devices is still disconnected despite the corresponding control or only when a high potential or high voltage is determined despite the corresponding control. For this purpose, the control device is connected to the switching device and the high-temperature fuse device in a controlled manner. In particular, the control device is set up to first operate the switching device, and then after checking the effect of the switching device disconnection, if a high potential can still be determined despite the disconnection (on the side of the high-temperature fuse device facing away from the battery), the high-temperature fuse device is triggered.

[0015] The connection point or the two switching devices can be connected to the battery via a release device. For example, during maintenance, the release device can be used to switch a segment of the vehicle electrical system to a voltage-free state. The release device is connected in series at the same potential that the diode is also at, as long as the diode is arranged in the first switching device. In particular, the release device is at the same potential as the high-temperature fuse device (or at the same busbar) or can be designed as a bipolar. The release device can be present between the high-temperature fuse device and the battery. In addition, the high-temperature fuse device can be present between the release device and the battery. Not only the high-temperature fuse device but also the release device (if present) can only be set at one of the two potentials (especially the potential that the diode (if present) is also at), and the other potential is transmitted through a direct connection between the connection point and the battery.

[0016] The release device can be a power switch, a circuit breaker, a fuse, a load disconnect switch, a residual current switch or a plug-in device with a disconnect function. Preferably, the release device is a detachable jumper. If the jumper is removed from the support, the two contacts are separated from each other, and when the jumper is plugged in, the two contacts are connected to each other by the jumper.

[0017] The vehicle electrical system can be equipped with a rectifier. In addition, an AC charging terminal can be provided, which is connected to the first side of the DC voltage converter via the rectifier. The second side of the DC voltage converter is (directly) connected to at least one high-voltage consumer. A further switching device can be provided, which is arranged between the first side of the DC voltage converter and the first switching device. The DC charging terminal can be connected directly to the first switching device or the changeover switch, or can be connected to the first switching device or the changeover switch via a further (safety) switching device.

[0018] A further DC voltage converter (hereinafter: additional converter) can be provided as a high-voltage load. The further DC voltage converter can have a first side, which is connected to the first side of the DC voltage converter. The second side of the additional converter can be connected to a low-voltage electrical system, for example an electrical system segment having a terminal voltage of approximately 12, 13, 14, 24 or 48 volts.

[0019] Other high-voltage loads can be provided, which are connected to the changeover switch (the changeover switch connects the high-voltage load to the first or second switching device in a switchable manner). In this case, this can be, for example, a heating device, in particular an electric heating device of a catalytic converter, or an air-conditioning device, for example an electric air-conditioning compressor or an electric interior heating element. A further switch can be provided between at least one high-voltage load and the changeover switch. The switch can be designed as a semiconductor fuse, in particular as an IGBT, with a diode connected in parallel to the IGBT. In the event of a fault, the semiconductor fuse is disconnected by a control signal.

[0020] The battery and the release device, the battery and the high-temperature fuse device, or the battery, the release device, and the high-temperature fuse device may be arranged in one housing, while the remaining components of the vehicle electrical system are arranged in at least one other housing.

[0021] The vehicle electrical system is preferably a high-voltage electrical system with a nominal voltage of at least 60 volts, 100 volts, 200 volts, 400 volts or 800 volts (at least in sections). The battery is preferably a traction battery, in particular a high-voltage battery. The battery can be a lithium battery. The battery has a nominal voltage of, for example, 400 volts or 800 volts. The rectifier between the AC charging terminal and the first side of the DC voltage converter can be an uncontrolled rectifier, a controlled rectifier or a power factor correction filter. In addition, other voltage converters can be arranged between the rectifier and the DC voltage converter. A filter can be arranged between the first side of the DC voltage converter and the first switching device.

[0022] The vehicle electrical system may have an electric drive. The electric drive may in particular have an inverter and an electric motor connected to the inverter. The electric drive, in particular the inverter, is connected to the battery via a second switch unit. Alternatively or in combination therewith, the electric drive may be connected to a high-voltage consumer via the switch when the changeover switch is in the second switch position. If the changeover switch is in the second switch position, the electric drive may be supplied with power from the battery or may be regenerated into the battery. This assumes that the second switch unit is closed. Therefore, in this case, which may also be referred to as a driving state, the electric drive is connected to the battery. At the same time, the first switch unit is preferably disconnected. Since the changeover switch is designed in such a way, there is no connection between the electric drive and the DC charging terminal, in particular the changeover switch should be in the first switch position and not in the second switch position. As a result, when the battery is connected to the electric drive or to the high-voltage consumer, the DC charging terminal is disconnected, so that a possibly relatively high Cy capacitance (=filter capacitor for conducting the AC component to the ground) of the electric drive cannot act on the DC charging terminal. Furthermore, it is ensured that in driving mode the DC voltage terminals are disconnected from the battery and from the electric drive and from high-voltage loads. When the selector switch is in the second switch position and in particular when the first switching unit is open, high contact voltages at the DC charging terminals are avoided.

[0023] The electric drive can be connected to the connection connecting the changeover switch to the second switching unit, in particular in a direct manner. Therefore, the electric drive can be connected between the changeover switch and the second switching unit. The high-voltage consumer can be connected to the changeover switch on the side of the changeover switch facing away from the second switching unit. Therefore, the changeover switch US can be located between the electric drive and the high-voltage consumer. Therefore, the electric drive is connected to the side of the second switching unit facing the changeover switch. The electric drive is connected to the side of the changeover switch facing the second switching unit.

[0024] The DC charging terminal can be connected to the connection connecting the changeover switch to the first switching unit. In other words, the DC charging terminal can be connected to the side of the first switching unit facing away from the battery. In particular, the DC charging terminal can be connected to the side of the changeover switch facing the first switching unit. In one embodiment, the changeover switch includes a first contact and a second contact, which can be connected to the high-voltage consumer in an optional manner. In this case, the first contact is (directly) connected to the DC charging terminal. The first contact is especially connected to the side of the first switching unit facing away from the battery. The second contact of the changeover switch can be directly connected to the second switching unit. In particular, the second contact can be directly connected to the electric drive or its inverter. The second contact is connected to the side of the second switching unit facing away from the battery. The side of the switch unit connected to the changeover switch or to its first and second contacts is opposite to the side connected to the battery.

[0025] The vehicle electrical system can also have an AC voltage terminal. In addition, a rectifier can be provided, to which the AC voltage terminal is connected. In this case, the AC voltage terminal is connected to the AC voltage side of the rectifier. The AC voltage terminal is connected to the high-voltage consumer. If the changeover switch is in the second switch position, the AC voltage terminal is connected to the battery via the rectifier (and the second switch unit). The rectifier is preferably connected to the side of the changeover switch that is connected to the high-voltage component. The AC voltage terminal can also be connected to the point at which the electric drive is connected to the second switching device. The AC voltage terminal can therefore be connected to the connection between the second switch unit and the changeover switch via the rectifier or to the second contact of the changeover switch. Thus, energy can be fed into the battery via the AC voltage terminal and the rectifier and via the changeover switch and the second switch unit. In such an AC charging state, the first switch unit is preferably disconnected. In addition, the changeover switch is in a position where the rectifier is connected to the second switch unit. Thus, the DC charging terminal is separated from the battery and also from the rectifier via the changeover switch and the open first switch unit on the one hand.

[0026] The changeover switch is in particular bipolar, so that the first and second contacts are each present in duplicate, wherein a first contact and a second contact are each reserved for the positive potential and a further first contact and a further second contact are associated with the negative potential or ground potential.

[0027] A DC voltage converter can be provided, which changes the voltage rectified by the rectifier in terms of its level, so as to charge the battery with a corresponding high voltage via the changeover switch and the second switching unit. The rectifier is connected to the side of the changeover switch connected to the high-voltage component via the DC voltage converter. The rectifier is connected to the side of the changeover switch opposite to the first and second contacts by means of the DC voltage converter, and is especially connected to the high-voltage component. Another possibility is that the rectifier is connected to the second contact of the changeover switch, i.e., to the second switching unit and especially to the side of the switching unit facing the changeover switch, via the DC voltage converter.

[0028] The high-voltage component can be an electric heater, for example an electric heater of an air-conditioning device and / or an electrically heatable exhaust gas catalytic converter. Furthermore, alternatively or in combination therewith, an electric air-conditioning compressor (or its drive) and / or an additional DC voltage converter can be provided, which is provided as a high-voltage component and is connected accordingly to the high-voltage component. The additional DC voltage converter is in particular a DC voltage converter to which a low-voltage grid, for example a low-voltage grid with a nominal voltage of 12 volts, 13, 14, 24, 36 or 48 volts, is connected. One or more high-voltage components can be fed from a battery or, if the battery (dieser) is connected, can be fed via a DC charging terminal or also a rectifier or a DC voltage converter via an AC charging terminal.

[0029] One embodiment provides that the vehicle electrical system has a control device, which is connected to the changeover switch in an actuating manner. The control device has a vehicle state. In this vehicle state, the control device actuates the changeover switch so as to adopt a second switch position. In addition, a charging state, in particular a DC charging state, can be set. In this charging state, the control device actuates the changeover switch so as to actuate the first switch position. In the driving state, the changeover switch thus connects the battery to the high-voltage component. In the charging state or the DC charging state, the changeover switch disconnects the DC charging terminal from the electric drive and in particular connects the DC charging terminal to at least one high-voltage consumer. In addition, in the DC charging state, the DC charging terminal is connected to the battery via the first switching unit.

[0030] The control device is preferably further connected to the switching device in a controlled manner. In the driving state, the control device controls the first switching device to be in an open state. In addition, in the driving state, the control device controls the second switching device to be in a closed state. The DC charging terminal is separated from the battery by the open first switching device, so that no dangerous voltage can be applied to the DC charging terminal during driving. The battery is connected to the electric drive device by the closed second switching device. Since the changeover switch is preferably in the second switch position in this case, at least one high-voltage consumer is also supplied with electrical energy from the battery via the changeover switch. In the DC charging state, the control device controls the first switching device to be in a closed state and controls the second switching device to be in an open state. In view of the switching device, the switch positions in the driving state and in the DC charging state complement each other.

[0031] In the DC charging state, a power path between the DC charging terminal and the battery is set via the first switching device. However, the battery is separated from the vehicle drive device by the open second switching device. Since the changeover switch is in the first switch position in this case, the DC charging terminal is connected to at least one high-voltage consumer, so that the at least one high-voltage consumer can be powered thereby. However, since the changeover switch is not in the second position in the DC charging state, the electric drive device is also separated on the side of the changeover switch. Therefore, when the vehicle electrical system or the control device and related devices are in the DC charging state, the Cy capacitor of the electric drive device is separated from the remaining vehicle electrical system.

[0032] The changeover switch and the first and second switching units are preferably configured as bipolar. In this case, the switching elements are provided for positive voltage and negative potential (or ground potential), respectively. Thus, the changeover switch and the switching unit are unipolar in view of the two potentials of the vehicle electrical system.

[0033] The changeover switch and / or the switching unit or its switching element is in particular an electromechanical switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 For explaining embodiments of the vehicle electrical system described herein. DETAILED DESCRIPTION

[0035] Figure 1 The vehicle electrical system FB shown in FIG is connected to an external voltage source, namely an AC voltage source WQ and a DC voltage source GQ, via a charging interface LS. These sources can be implemented as a charging station, for example. The vehicle electrical system FB includes an AC voltage terminal WA and a DC voltage terminal GA. It should be noted that the AC voltage terminal WA is optional. Terminals WA, GA are part of the charging interface LS.

[0036] The battery AK of the vehicle electrical system is connected to the connection point VP, wherein the connection is shown to be carried out via the optional elements PF (pyrofuse-Sicherung) and FE (release device (Freischalteinrichtung)). These two optional components are set at the same potential. The first switching unit includes a switching element S1 for the potential N (negative potential) and a diode D for the positive potential P. The diode has a conduction direction, which points to the current direction in which the charging current occurs for the DC charging terminal. However, it is preferred that other switching elements are used instead of the diode D, and the other switching elements are connected at the position where the diode is provided instead of the diode. The second switching unit includes switching elements S1 and S2, wherein a switch or switching element is also provided for each potential N, P. Switch S2 is set in the negative potential N, and switch S3 is set in the positive potential P. The switching elements are respectively connected in series (at the relevant potential). As a result, the lines with respective potentials can be separated (trennen) and connected in a controlled manner.

[0037] A parallel path, each including one of the two switch units, leads from the connection point VP or from the battery AK. One of the two switch units is arranged in one of the paths (connected in series); different switch units are arranged in different paths. The changeover switch US is also connected to the switch unit, but is connected on the opposite side to the connection point or the battery. The changeover switch is a first switch unit that connects the first (bipolar) contact or terminal of the changeover switch US (the first (bipolar) contact or terminal corresponds to switch position 1) to the battery or the connection point VP. The second (bipolar) contact or terminal of the changeover switch US corresponding to switch position 2 is connected to the connection point or to the battery AK via the second switch unit.

[0038] The center terminal of the changeover switch US, i.e. the terminal which can be selectively connected to the switch position 1 or 2 depending on the switch position, is connected to at least one high-voltage consumer. In this case, high-voltage consumers K and W2 are provided. The at least one high-voltage consumer K can represent a heating element (of an air-conditioning system or an exhaust gas aftertreatment device) and / or an electric air-conditioning compressor (or its drive) and / or other components.

[0039] The electric drive comprises an inverter I and an electric motor M, which is connected to a changeover switch US (in particular to its second contact / terminal) and to a second switching unit S2, S3 via the inverter I. The changeover switch US is connected between the electric drive (traction drive) on the one hand and at least one high-voltage consumer or the first switching unit S1, D on the other hand. Thus, at least one high-voltage consumer can be optionally connected to the first switching unit S1, D or to the second switching unit S2, S3.

[0040] The DC charging terminal GA is connected to the connection between the first switching unit S1, D and the changeover switch US, in particular its first contact 1. In other words, the DC charging terminal GA is connected to a first path, which leads from the battery or from the connection point to the changeover switch, while the electric drive is connected to a second path, which connects the connection point VP or the battery to the changeover switch US.

[0041] The control device ST is connected in a controlled manner to the switches S1 to S3 (also to the switching elements in the case of diode measures (Schritt)) and to the changeover switch US in a controlled manner. In charging operation, the DC voltage terminal is connected to the connection point or the battery AK via the charging unit S1, D, which is then closed. In the charging state, the second switching unit is disconnected, so that there is no connection to the electric drive I, M from the side of the second switching unit. In the charging state, the changeover switch US is in the switching position 1 and thereby connects at least one high-voltage consumer to the connection point VP or the battery AK on the one hand and to the DC charging terminal GA on the other hand. As a result, the high-voltage consumers K, W2 and NV receive the supply voltage, while the inverter and thus the entire electric drive I, M are isolated due to the switch position of the changeover switch US in the switching position 1 and due to the disconnected second switching units S2, S3. As a result, the Cy capacitor does not act on the DC charging terminal GA. High contact voltages are thus avoided.

[0042] As mentioned, a heating element and / or an electric air conditioning compressor can be provided as a high-voltage consumer. The heating element and / or the electric air conditioning compressor are symbolically shown as a component K. An additional DC voltage converter W2 can be provided as a further high-voltage consumer, which connects the central terminal of the switching switch US to the low-voltage electrical system NV in a voltage conversion manner. A multi-phase additional DC voltage converter W2 is shown, which is a current-isolating type, wherein the output terminal is only an example of many output terminals. The low-voltage electrical system can have a nominal voltage of 12 volts, 13 volts or 14 volts or even other values ​​below 60 volts.

[0043] As an optional embodiment, an AC voltage terminal WA can be provided, which is connected to the rectifier GR, in particular via an optional switch SW. The rectifier GR thus connects the AC voltage terminal to the DC voltage converter W2, in particular to the first side 1S of the DC voltage converter W1. The second side 2S of the DC voltage converter is connected to at least one high-voltage consumer K, W2, NV.

[0044] After having described the switch positions in the charging state for the DC voltage case (=DC charging state) above, the AC charging state is described below. In this case, the changeover switch US is in the second switching state 2 (i.e. the center terminal is connected to the terminal of the switch position 2) and the second switching unit is closed, while the first switching unit is open. Since the changeover switch US does not connect the DC voltage converter W2 to the DC charging terminal GA in this case and since the first switching device S1 is open, the voltage obtained in the case of AC charging (in particular the voltage at the second side 2S) is not applied to the DC charging terminal GA. Since the DC voltage converter W1 is also a galvanic isolation converter in this case, the inverter I and the Cy capacitor of the motor M do not act on the AC charging terminal WA.

[0045] An alternative connection point for the DC charging terminal is marked with an X, wherein this point is located between the second switching units S2, S3 and the changeover switch US. In this case, the DC charging terminal is connected directly to the inverter I (and therefore also to the motor M), wherein it can be provided that the Cy capacitor is switchable and is disconnected in the charged state.

[0046] For simplicity, the connections shown on the left side of the second switching unit and above and below the connection points between the first switching unit, the changeover switch and the DC charging terminal are shown with a single line. However, these connections should be understood as two-wire connections and are in the same manner as in Figure 1 Those connections which are explicitly shown with two potentials and therefore with two lines are designed identically. Thus, a single line in particular represents a two-wire connection with two potentials (N, P).

[0047] In general, a DCDC converter (buck or boost) can be arranged from a first switching device (equipped with two switching elements or equipped with a switching element and a diode) to the connection point of the DC charging terminal and the conversion switch. The control device can be connected to the DCDC converter in a controlled manner and is configured to disconnect one or more (working) switches of the DCDC converter in the event of an overcurrent. If the first switching device is designed with a diode D, the diode constitutes the working diode of the DCDC converter. If the DCDC converter is constructed as a boost converter, the working diode immediately following the working inductor is constructed by a diode D. Since in one embodiment the diode D is part of both the DCDC converter and the first switching unit, the DCDC converter and the first switching unit can be partially integrated with each other and in particular can share a device, namely a diode.

[0048] Even in the case of a circuit without a commutation switch as shown in application DE 10 2019 215 855, a DCDC converter (boost type, boost converter) can be provided between the first switching unit and the connection point of the DC charging terminal, the diode of which is implemented by a diode device. The diode or the diode device can thus be integrated in the DCDC converter, which is integrated with the first switching device.

Claims

1. A vehicle electrical system (FB), comprising at least one high-voltage consumer, a DC charging terminal (GA), a battery (AK), a rectifier (GR) and a changeover switch (US), wherein the high-voltage consumer is connected to the battery (AK) via the changeover switch (US) in a first switch position (1) of the changeover switch (US) via a first switching device (S1, D), and is connected to the battery (AK) via the changeover switch (US) in a second switch position (2) of the changeover switch (US) via a second switching device (S2, S3), wherein the DC charging terminal (GA) is connected to the battery (AK) via the first switching device (S1, D).

2. The vehicle electrical system (FB) according to claim 1 further comprises an electric drive (I, M), which is connected to the battery (AK) via the second switching device (S2, S3), and the electric drive is connected to the high-voltage consumer via the changeover switch (US) in the second switch position (2) of the changeover switch (US).

3. The vehicle electrical system (FB) according to claim 2, wherein the electric drive device (I, M) is connected to a connecting line connecting the change-over switch (US) to the second switching device (S2, S3).

4. The vehicle electrical system (FB) according to claim 1, 2 or 3, wherein the DC charging terminal (GA) is connected to a connecting line connecting the changeover switch (US) to the first switching device (S1, D).

5. A vehicle electrical system (FB) according to any one of claims 2 to 3, further comprising an AC voltage terminal (WA) and a rectifier (GR), the rectifier being connected to the side of the switching switch (US) connected to the high-voltage consumer or to the point (X) at which the electric drive (I, M) is connected to the second switching device (S2, S3).

6. The vehicle electrical system (FB) according to claim 5 has a first DC voltage converter (W1), and the rectifier is connected to the side of the switching switch connected to the high-voltage consumer via the first DC voltage converter, or the rectifier is connected to the connection point (X) via the first DC voltage converter.

7. A vehicle electrical system (FB) according to any one of claims 1 to 3, wherein the high-voltage consumer is constructed as an electric heater of an air-conditioning system or as an electrically heatable exhaust gas catalytic converter and / or as an additional DC voltage converter.

8. The vehicle electrical system (FB) according to any one of claims 1 to 3, comprises a control device (ST), which is connected to the switching switch (US) in a control manner, and the control device has a driving state, in which the control device (ST) controls the switching switch (US) to set the second switch position, and wherein the control device (ST) has a DC charging state, in which the control device (ST) controls the switching switch (US) to set the first switch position.

9. A vehicle electrical system (FB) according to claim 8, wherein the control device (ST) is further connected to the first switching device (S1, D) in a controlled manner and is connected to the second switching device (S2, S3) in a controlled manner, wherein the control device (ST) controls the first switching device (S1, D) to be in an open state and controls the second switching device (S2, S3) to be in a closed state in the driving state, and wherein the control device (ST) controls the first switching device (S1, D) to be in a closed state in the DC charging state and controls the second switching device (S2, S3) to be in an open state.

10. The vehicle electrical system (FB) according to any one of claims 1 to 3, wherein the changeover switch (US) and the first switching device and the second switching device are designed as bipolar.

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