Low-voltage electrical system for a vehicle and vehicle electrical system

Abstract

The low-voltage (LV) electrical system (1) comprises a first LV sub-system (11) with at least one first LV component (111) configured to control and / or monitor at least one first high-voltage (HV) component (311) located outside a crash-safe area (5) of the vehicle. The LV electrical system (1) includes a second LV sub-system (12) comprising at least one second LV component (121) with a first predefined safety relevance. The two LV sub-systems (11, 12) are connected via a first supply path (CI30) and a second supply path (CI31) to supply power to the first LV sub-system (11). If a voltage between the two supply paths (C130, C131) exceeds a predetermined voltage amount, the conductive electrical connection between the LV sub-networks (11, 12) is interrupted by a fuse disconnector device (9), so that the first LV sub-network (11), which is at great risk from faulty HV connections, for example due to a crash, is separated from the second LV sub-network (12).

Description

[0001] The present disclosure relates to a low-voltage electrical system for a vehicle and to a vehicle electrical system comprising the low-voltage electrical system.

[0002] Electric vehicle manufacturers typically place high-voltage components in crash-resistant areas within the vehicle. A crash-resistant area is defined as a region where there is a relatively low probability that the high-voltage components will be damaged in a vehicle crash. The passenger compartment, for example, is a particularly crash-resistant area. If high-voltage components cannot be placed in crash-resistant areas, they are preferably equipped with a more robust housing to better withstand higher impact loads.

[0003] Another alternative or supplementary measure is to ensure, by means of a protective device or function, that if one of the high-voltage components is damaged in a crash and, for example, the high-voltage electrical system is short-circuited with the low-voltage electrical system, that the damaged high-voltage electrical system does not pose a danger to safety-relevant functions of the vehicle, in particular to safety-relevant functions in the low-voltage area.

[0004] An example of such a protective device is a “rapid discharge circuit” located in the high-voltage battery housing, which discharges the entire high-voltage DC network of the vehicle within a few milliseconds (e.g. 20 ms) after a crash in order to protect the low-voltage area from high energy and high voltage from the HV DC network.

[0005] This requires dissipating all the energy stored in the high-voltage (HV) components of the high-voltage (HV) DC network due to their capacitive properties. Such a rapid discharge circuit must meet high ASIL requirements (e.g., ASIL D) to safely and reliably prevent energy transfer from all possible energy sources in the HV DC network (HV-LV DCDC, traction inverters, etc.) to the low-voltage DC network. Due to these high ASIL requirements, the complexity and overall system costs are very high.

[0006] Furthermore, it takes a certain amount of time (e.g. 20 ms) for such a discharge circuit or discharge function to reach a safe state for the low-voltage range.

[0007] One challenge to be solved is therefore to provide a low-voltage electrical system that enables reliable operation of safety-relevant low-voltage consumers during or after a vehicle crash, and that can be provided with minimal effort.

[0008] The problem is solved by the features of the independent patent claims. Advantageous further developments are characterized in the dependent claims.

[0009] According to one aspect, the problem is solved by a low-voltage electrical system (LV electrical system) for a vehicle, where the vehicle has a high-voltage electrical system (HV electrical system) and the LV electrical system. The vehicle is, for example, an electrically powered vehicle, in particular a purely battery-powered vehicle.

[0010] In this application, an on-board network is understood to mean an on-board network for energy supply or energy provision (on-board energy network).

[0011] In this application, an electrically powered vehicle is understood to mean a purely battery-powered vehicle (Battery Electric Vehicle, BEV) that has an electric motor as its sole source of propulsion, or a hybrid-electric vehicle (Hybrid Electric Vehicle, HEV or Plug-In Hybrid Electric Vehicle, PHEV) that has a combination of an internal combustion engine and an electric motor as sources of propulsion. The term "electric vehicle" includes not only motor vehicles, but all electrically powered vehicles, such as industrial trucks or forklifts.

[0012] The vehicle's high-voltage (HV) electrical system comprises a first HV sub-system with first HV components located outside a crash-resistant area of ​​the vehicle and outside a crash-resistant enclosure. The HV electrical system has, in particular, a nominal operating DC voltage greater than 60 V, specifically a nominal operating DC voltage of 400 V or 800 V. The vehicle's HV electrical system may include a second HV sub-system with second HV components located within a crash-resistant area of ​​the vehicle and / or within a crash-resistant enclosure.

[0013] The low-voltage (LV) electrical system comprises a first LV sub-network and a second LV sub-network. The first LV sub-network has at least one first LV component configured to control, regulate, and / or monitor at least one of the first high-voltage components. This means that the first LV component is directly or indirectly connected or coupled to one or more first high-voltage (HV) components for transmitting and / or receiving signals.

[0014] The second low-voltage (LV) subnetwork has at least one second LV component that has a predefined first safety relevance. The first safety relevance includes, for example, compliance with requirements according to ASIL C or ASIL D. The at least one second LV component is therefore safety-relevant. Different ASILs can be assigned to the second LV components.

[0015] The first low-voltage (LV) components of the first LV subnetwork preferably have a lower safety relevance than the at least one second LV component. The safety relevance of the first LV components can, for example, include compliance with the requirements of a Q-level or ASIL A or ASIL B. The first LV components are therefore preferably not safety-relevant or less safety-relevant.

[0016] A first supply path, connected to a first low-voltage potential of a low-voltage power source of the vehicle, is arranged between the first and second low-voltage sub-networks. Furthermore, a second supply path, connected to a reference potential of the vehicle, is arranged between the first and second low-voltage sub-networks. The reference potential is preferably a ground potential of the vehicle or a chassis potential. The first and second supply paths are, in particular, the only supply paths between the first and second low-voltage sub-networks that exhibit the first low-voltage potential and the reference potential, respectively. That is to say,There is no further supply path between the first LV subnetwork and the second LV subnetwork that has the first low-voltage potential and no further supply path that has the reference potential.

[0017] A fuse disconnect device is arranged in the first and / or second supply path. This device is configured to interrupt an electrically conductive connection of the first or second supply path, respectively, when a voltage between the first and second supply paths exceeds a predetermined voltage level and / or when the fuse disconnect device receives a crash signal. This interruption effectively isolates the first low-voltage (LV) sub-network from the second LV sub-network. The isolation is preferably single-pole, but can also be multi-pole. Signal lines between first LV components of the first LV sub-network and second LV components of the second LV sub-network are not disconnected by this isolation.

[0018] The fuse disconnect device is located, for example, in the second low-voltage (LV) sub-system for connection to a power supply network. Alternatively or additionally, the fuse disconnect device can also be powered by a high-voltage to low-voltage DC / DC converter located in a crash-resistant area of ​​the vehicle and / or in a crash-resistant housing.

[0019] The electrical connection provided by the first supply path thus corresponds to terminal 30 of the vehicle, and the electrical connection provided by the second supply path corresponds to terminal 31 of the vehicle.

[0020] The fuse disconnect device is designed to disconnect the electrical connection within a very short time, in particular in less than 1 millisecond or even in less than 100 microseconds or 10 microseconds.

[0021] Insofar as the first supply path and / or the second supply path each have a plurality of electrically conductive individual conductors, the fuse disconnector device has a plurality of disconnecting switches so that all electrically conductive individual conductors are disconnected and the first supply path or the second supply path is completely interrupted.

[0022] In at least one advantageous embodiment according to the first aspect, the energy source is a low-voltage vehicle battery arranged in the second LV sub-network and providing a power supply to the LV network, with a power supply to the first LV sub-network being provided via the first supply path and the second supply path. Alternatively, the energy source can be a low-voltage vehicle battery arranged in the first LV sub-network and providing a power supply to the LV network, with a power supply to the second LV sub-network being provided via the first supply path and the second supply path.In another alternative embodiment, the energy source can be a high-voltage to low-voltage DC converter located in a crash-proof area of ​​the vehicle and / or in a crash-proof housing, providing a power supply for the LV electrical system, with a respective power supply for the first LV sub-system and the second LV sub-system being provided via the first supply path and the second supply path.

[0023] For example, a low-voltage vehicle battery provides a nominal supply voltage of 12 V, 24 V, or 48 V.

[0024] The first high-voltage (HV) components and their associated first low-voltage (LV) components are, in most cases, located in close proximity to each other. Since the first HV components of the first HV sub-wiring system are not crash-protected, deformations of the first HV sub-wiring system due to a vehicle crash can, for example, lead to a short circuit between a conductor of the first HV sub-wiring system carrying a high-voltage potential and a supply line of the first LV sub-wiring system carrying the positive terminal potential of the LV vehicle battery, or a supply line of the first LV sub-wiring system carrying the vehicle's reference potential, or a signal line of the first LV components. Even if a traction battery is already disconnected from the HV system due to the vehicle crash, a significant amount of energy remains stored in the HV system due to the capacitive properties of the HV components.

[0025] The low-voltage (LV) electrical system, as described in the first aspect, prevents overvoltage caused by high-voltage (HV) components and / or the HV system's capacitance in the first LV sub-system, as well as the energy stored in the HV system, from being conducted into the second LV sub-system. This prevents damage to the second LV components, allowing them to continue operating. If a conductor in the first HV sub-system, for example, one carrying a positive high-voltage potential, is short-circuited with a signal line of a first LV component, the potential is shunted to ground via the ESD protection diodes of the first LV component, creating a large potential difference between the first and second supply paths. Consequently, the circuit breaker will trip in this case as well.

[0026] This ensures the availability of secondary low-voltage (LV) components, such as an eCall (automatic emergency call after a crash), following a crash event. It is known to implement measures for safety-relevant components in low-voltage electrical systems that allow for the disconnection of low-voltage loads causing a short circuit or overvoltage within the system, and / or the connection or disconnection of a low-voltage power source as needed. However, these measures cannot prevent damage to safety-relevant components if, for example, a high-voltage potential is introduced into the low-voltage system during a crash.

[0027] The described LV electrical system has the further advantage that the second LV sub-system can be separated from the ground path and thus meet the SELV (Safety Extra Low Voltage) requirements.

[0028] In at least one advantageous embodiment according to the first aspect, the fuse disconnector device includes a semiconductor switch having a maximum dielectric strength that exceeds the nominal DC operating voltage of the HV electrical system by a predetermined amount. For example, the predetermined amount is approximately 50% of the nominal DC operating voltage. If the HV electrical system has a nominal DC operating voltage of 800 V, for example, the semiconductor switch has a maximum dielectric strength of at least 1000 V, 1200 V, or 1400 V. If the HV electrical system has a lower nominal DC operating voltage of, for example, 400 V, it is sufficient for the semiconductor switch to have a maximum dielectric strength of at least 600 V, 700 V, or 800 V.

[0029] In at least one advantageous embodiment according to the first aspect, the fuse disconnector device is designed to be bidirectionally blocking. Thus, when the switch is in an open position, no current flows in either direction.

[0030] In at least one advantageous embodiment according to the first aspect, the fuse disconnector device comprises a control unit and a measuring circuit. The measuring circuit is configured to detect a measurement signal representative of a voltage between the first and second connection paths and to provide it to the control unit. The control unit is configured to control a switching position of the fuse disconnector device, in particular the semiconductor fuse disconnector device, depending on the measurement signal. It is sufficient to detect the voltage between the first and second connection paths because, even if a signal line is affected by such a short circuit, the potential is discharged or routed to the first or second supply path via ESD protection diodes of the first low-voltage components.

[0031] In at least one advantageous embodiment according to the first aspect, the fuse disconnector device includes a diode having a minimum breakdown voltage that exceeds the nominal DC operating voltage of the HV electrical system by a predetermined additional amount. The diode is, in particular, designed as a semiconductor diode. The diode can be implemented using a transistor. For example, the predetermined additional amount is approximately 50% of the nominal DC operating voltage. If the HV electrical system has, for example, a nominal DC operating voltage of 800 V, the diode has a minimum breakdown voltage of at least 1000 V, 1200 V, or 1400 V. If the HV electrical system has a lower nominal DC operating voltage of, for example, 400 V, it is sufficient for the diode to have a minimum breakdown voltage of at least 600 V, 700 V, or 800 V.

[0032] The semiconductor switch comprises, or is formed by, a metal-oxide-semiconductor field-effect transistor (MOSFET). The MOSFET includes a body diode. The diode and the body diode are arranged in anti-series.

[0033] In at least one advantageous embodiment according to the first aspect, the fuse disconnect device has a current-limiting element, in particular a current-gradient-limiting element. The fuse disconnect device can have an inductive component, for example, a coil. When a current begins to flow through the coil, this creates a magnetic field. According to Faraday's law of induction and Lenz's law, a voltage is then induced in the coil, which, together with the associated current, opposes the original current flow, so that the current increases with a delay.

[0034] In at least one advantageous embodiment according to the first aspect, the second low-voltage (LV) sub-network has at least one redundant power source for supplying at least one of the second LV components. This allows at least one LV component to operate independently of the actual power sources (traction battery in conjunction with a high-voltage / low-voltage DC / DC converter and low-voltage vehicle battery). Safety-relevant LV components often incorporate further safeguards against overvoltage (EMC and voltage spikes) and short circuits caused in the low-voltage electrical system. This means that a part of the LV network containing the safety-relevant LV component is isolated from another part of the LV network if, for example, a short circuit is caused in the latter by another LV component.However, these measures are not sufficient to prevent an HV / LV short circuit, which can occur particularly during a crash.

[0035] In at least one advantageous embodiment according to the first aspect, the at least one first low-voltage (LV) component is located adjacent to one of the first high-voltage (HV) components, and / or on the same assembly as one of the first high-voltage components, and / or on an assembly that is mechanically coupled to the assembly on which one of the first HV components is located. In particular, the at least one first HV component can be the first HV component that is controlled, regulated, and / or monitored by the at least one first LV component. "Adjacent" in this context means, in particular, in a common housing.

[0036] This proximity of the first LV components to the first HV components increases the probability that, in a vehicle crash, a conductor carrying a high-voltage potential will be short-circuited with a conductor carrying the positive terminal potential of the low-voltage battery or with a conductor carrying the vehicle's reference potential, thus causing an overvoltage at the supply inputs of the first LV components and other LV components connected to the first LV sub-network, leading to the destruction of the components.

[0037] In at least one advantageous embodiment according to the first aspect, the second LV subnetwork is free of first LV components, each of which is configured to control and / or regulate and / or monitor at least one of the first high-voltage components.

[0038] All secondary LV components of the secondary LV sub-wiring system preferably have a sufficient spatial and structural distance from the primary HV components. Sufficient spatial distance is defined as such that, in the event of a vehicle crash, the probability of a conductor carrying a high-voltage potential being short-circuited to a supply conductor of the secondary LV sub-wiring system (carrying the positive terminal potential of the LV vehicle battery), to a supply conductor of the secondary LV sub-wiring system (carrying the vehicle's reference potential), or to a signal conductor of one of the secondary LV components is extremely low and therefore does not need to be considered further when designing a safety concept to achieve a specific ASIL. Furthermore, at least some of the secondary LV components can also be located in a crash-resistant area of ​​the vehicle, for example, in a passenger compartment.

[0039] In at least one advantageous embodiment according to the first aspect, the signal lines of the at least one second LV component, which electrically connect the at least one second LV component to another LV component located in a different LV subnetwork, each have a protective diode. The protective diodes prevent a circuit from forming via the signal lines that could conduct a fault current. If the circuit breaker is located in only one of the two connection paths, it is advantageous if the other connection path also has a protective diode.

[0040] According to a second aspect, the task is solved by a vehicle electrical system comprising a high-voltage electrical system (HV electrical system) with a first HV sub-electrical system comprising first HV components located outside a crash-safe area of ​​the vehicle and outside a crash-safe enclosure, and a low-voltage electrical system (LV electrical system) according to the first or second aspect.

[0041] In at least one advantageous embodiment according to the second aspect, the HV on-board power supply has a second HV sub-on-board power supply with second HV components that are arranged within a crash-safe area of ​​the vehicle and / or within a crash-safe housing.

[0042] In at least one advantageous embodiment according to the second aspect, the LV on-board power supply comprises a third LV sub-on-board power supply with at least one third LV component, which is configured to control and / or regulate and / or monitor and / or supply one or more of the second HV components, and which is arranged within the crash-safe area of ​​the vehicle or within the crash-safe housing.

[0043] Optional variations of the first aspect may also be present in the third aspect and have corresponding effects.

[0044] Further advantageous embodiments are disclosed in the attached claims and in the following description of exemplary embodiments with reference to the attached figures. In the figures, the same reference numerals are used for elements with essentially the same function; however, these elements need not be identical in every detail.

[0045] The figures show: Fig. 1 a block diagram of a design of a low-voltage electrical system in a vehicle electrical system and Fig. 2 a block diagram of a vehicle electrical system configuration.

[0046] In embodiments described herein or shown in the drawings, any direct electrical connection or coupling, i.e., any connection or coupling without any additional intervening elements, may also be implemented by an indirect connection or coupling, i.e., a connection or coupling with one or more intervening elements, or vice versa, as long as the general purpose of the connection or coupling, for example, the transmission of a certain type of signal or the transmission of a certain type of information, is essentially maintained.

[0047] Fig. Figure 1 shows the electrical system 2 of an electric vehicle. The electrical system 2 comprises a high-voltage electrical system (HV electrical system) 3. The HV electrical system 3 comprises at least one first HV sub-electrical system 31. The HV electrical system 3 in Fig. For example, 1 additionally features a second HV partial on-board network 32.

[0048] The first HV sub-wiring system 31 comprises first HV components 311, 312, 313. These first HV components 311, 312, 313 include, for example, an HV vehicle compressor 311, a high-voltage PTC heater 312, and a first traction inverter 313. The first HV sub-wiring system 31, with its first HV components 311, 312, 313, is located outside a crash-resistant area 5 and outside a crash-resistant enclosure. The first HV components 311, 312, 313 may also include or be other components.

[0049] The second high-voltage (HV) sub-wiring system 32 is, for example, located in a crash-resistant area 5 of the vehicle and / or in a crash-resistant housing. The second HV sub-wiring system 32 comprises at least one second HV component 321. This second HV component 321 has, for example, a higher safety relevance than the first HV components 311, 312, 313 and is therefore located in the crash-resistant area.

[0050] The vehicle electrical system 2 further comprises a low-voltage electrical system (LV electrical system) 1. The LV electrical system 1 comprises a first LV sub-electrical system 11 and a second LV sub-electrical system 12.

[0051] The first LV subnetwork 11 comprises at least one first LV component 111, 112, 113, which is configured to control and / or regulate and / or monitor one or more of the first HV components 311, 312, 313. Fig. Figure 1 shows three exemplary first LV components 111, 112, 113: an HV vehicle compressor control 111, a high-voltage PTC heater control 112 and a traction inverter control 113.

[0052] The first low-voltage (LV) components 111, 112, 113 are preferably arranged adjacent to the first high-voltage (HV) components 311, 312, 313 that they control, regulate, or monitor. For example, the first LV components 111, 112, 113 are in the same housing (not crash-protected) as the associated first HV components 311, 312, 313. Alternatively or additionally, the first LV components 111, 112, 113 and the associated first HV components 311, 312, 313 can be arranged on the same assembly / circuit board or on an assembly / circuit board that is mechanically coupled to the assembly / circuit board on which the associated first HV component 311, 312, 313 is at least partially located. The mechanical coupling can, in particular, be a direct mechanical coupling.However, at least one first LV component 111, 112, 113 can also be adjacent to other first HV components 311, 312, 313, and / or on the same assembly / circuit board and / or on an assembly / circuit board that is mechanically coupled to the assembly / circuit board on which this other first HV component 311, 312, 313 is at least partially arranged.

[0053] The second low-voltage (LV) subnetwork 12 includes at least one safety-relevant second LV component 121. This second LV component 121 includes, for example, an automatic emergency call system, also known as eCall.

[0054] The at least one second LV component 121 has a safety relevance that is greater than the safety relevance of the first LV components 111, 112, 113. Preferably, the first LV components 111, 112, 113 are not safety-relevant or have only a low safety relevance.

[0055] The second low-voltage (LV) sub-network 12 is preferably free of first LV components 111, 112, 113 that control and / or monitor the first high-voltage (HV) components 311, 312, 313 of the first HV sub-network 31. All second LV components 121 of the second LV sub-network 12 preferably have a sufficient spatial and structural distance from the first HV components 311, 312, 313.

[0056] In the Fig. In the embodiment shown in Figure 1, the second LV sub-network 12 has an LV vehicle battery 7 for supplying voltage or energy to the LV on-board network 1.

[0057] Due to the safety relevance of the second low-voltage (LV) component 121, the second LV sub-system 12 can be equipped with a redundant power supply. The second LV sub-system 12 is connected, in particular, to a high-voltage-to-low-voltage DC / DC converter, which is located in a crash-resistant area of ​​the vehicle and / or within a crash-resistant housing, in such a way that, in the event of a fault in the LV system 1, when the LV vehicle battery 7 is disconnected from the second LV sub-system 12, the power supply for the second LV sub-system 12 is provided via the high-voltage-to-low-voltage DC / DC converter. Alternatively or additionally, it is possible that at least one safety-relevant second LV component 121 has its own redundant power supply in order to bridge at least short-term power supply interruptions.

[0058] A first supply path CI30, connected to a positive terminal of the LV vehicle battery 7, is arranged between the first LV sub-network 11 and the second LV sub-network 12. A second supply path CI31, connected to a reference potential GND of the vehicle, in particular the chassis potential of the vehicle, is also arranged between the first LV sub-network 11 and the second LV sub-network 12. A negative terminal of the LV vehicle battery 7 is preferably connected to the reference potential GND of the vehicle. Under normal operating conditions, the second LV sub-network 12 is supplied with power from the LV vehicle battery 7 via the first supply path CI30 and the second supply path CI31. Preferably, the power supply to the second LV sub-network 12 from the LV vehicle battery 7, which is located in the first LV sub-network, is provided exclusively via the first supply path CI30 and the second supply path CI31. That is to say,There are no further supply paths between the first LV subnetwork 11 and the second LV subnetwork 12.

[0059] A fuse disconnect switch device 9 is arranged in the first supply path CI30 and / or the second supply path CI31.

[0060] The fuse disconnect switch device 9 is designed to interrupt an electrically conductive connection of the first connection path CI30 or the second connection path CI31 when a voltage between the first connection path CI30 and the second connection path CI31 exceeds a predetermined voltage amount and / or when the fuse disconnect switch device 9 receives a crash signal, thus disconnecting the first LV sub-network 11 from the second LV sub-network 12.

[0061] The fuse disconnect switch device 9, for example, has a control unit 93 which is designed to receive an analog crash signal that is present at terminal 30c of the vehicle and / or is provided by an airbag system of the vehicle.

[0062] The fuse disconnect device 9 can have a measuring circuit 95, for example a multi-stage voltage divider, configured to detect a measurement signal representative of a voltage between the first connection path CI30 and the second connection path CI31, and to provide the measurement signal to the control unit 93.

[0063] The control unit 93 is specifically configured to control the switching position of the fuse disconnector 9 based on the measurement signal. For example, the control unit 93 is configured to switch the fuse disconnector 9 to an open state when the voltage between the first connection path CI30 and the second connection path CI31 exceeds 20 V, 24 V, 27 V, 30 V, or 60 V, thus disconnecting the electrical connection between the first low-voltage (LV) sub-network 11 and the second LV sub-network 12. The voltage threshold can be selected based on the maximum voltage that the LV components can withstand for a certain period without failure. Many LV components in a 12 V low-voltage (LV) electrical system are designed for a maximum voltage of 35 V.Here, a voltage level that triggers the fuse disconnect device 9 is suitable in a range of 24 V to 30 V, in particular 27 V.

[0064] The fuse disconnector device 9 particularly comprises a semiconductor switch 91. The semiconductor switch 91 includes, for example, a metal oxide semiconductor field-effect transistor (MOSFET) or is formed by a MOSFET. The MOSFET preferably has a body diode.

[0065] The semiconductor switch 9 has a maximum voltage withstand rating of at least 1000 V, 1200 V, or 1400 V. In particular, the MOSFET can have a maximum permissible voltage VDSS between drain and source of 1000 V, 1200 V, or 1400 V.

[0066] The fuse disconnector 9 is, for example, configured to block bidirectionally. For this purpose, the fuse disconnector 9 can further comprise a diode 97 connected in anti-series to the body diode of the MOSFET. The diode 97 is, in particular, a semiconductor diode and has a breakdown voltage of at least 1000 V, 1200 V, or 1400 V. The diode can also be formed by a transistor.

[0067] The fuse disconnector device 9 can have a current-limiting element, in particular a coil, which limits a current increase in the event of a fault through the fuse disconnector device 9.

[0068] It is advantageous if the signal lines of the at least one second LV component 121, which galvanically couple or electrically connect the at least one second LV component 121 to other LV components outside the second LV subnetwork 12, which may also be a first LV component, each have a protective diode 123 that prevents a fault current from flowing through the signal lines. The protective diodes 123 are therefore preferably arranged in a rectified configuration. The at least one second LV component 121 is, for example, connected to a vehicle control unit via a terminal 30c signal line (analog crash signal) or a terminal 15 signal line (ignition starter switch). In the Fig. In the embodiment shown in Figure 1, the protective disconnect switch device 9 is arranged in the second connection path CI31 and the first connection path CI30 has a protection diode 123.

[0069] Fig. Figure 2 shows another embodiment of an LV electrical system 1 for a vehicle.

[0070] Unlike the one in Fig. In the embodiment shown in 1, the embodiment is in Fig. 2 the LV vehicle battery 7 is arranged in the second LV sub-system 12 and a voltage supply of the first LV sub-system 11 is provided via the first supply path CI30 and the second supply path CI31, in particular exclusively via the first supply path CI30 and the second supply path CI31.

[0071] In Fig. Figure 2 shows further second HV components 321, 322, 323 of the second HV sub-network 32, for example, the second HV components 321, 322, 323 include a power correction filter (PFC) 321, an HV / HV DC-DC converter 322 and an HV / LV DC-DC converter 323. The second high-voltage components 321, 322, 323 can also include or be other HV components.

[0072] Furthermore, the low-voltage (LV) electrical system 1 comprises a third LV sub-system 13 with third LV components 131, which is arranged in the crash-resistant area 5. The third LV components 131 are specifically designed to control, regulate, monitor, and / or supply the second high-voltage components 321, 322, 323. Signal lines and LV supply lines leading out of or into the crash-resistant area are protected, for example, by voltage-limiting elements and / or insulation.

[0073] In the future, the vehicle is planned to no longer have a low-voltage (LV) vehicle battery 7, but rather the LV components will be powered by the high-voltage / low-voltage DC-DC converter. In this case, the HV / LV DC-DC converter provides a power supply for the LV electrical system 1. A separate power supply for the first LV sub-system 11 and the second LV sub-system 12 can also be provided via the first supply path CI30 and the second supply path CI31. In particular, the first supply path CI30 can be connected to a first potential provided by the high-voltage / low-voltage DC-DC converter, and the second supply path CI31 can be connected to a second potential provided by the high-voltage / low-voltage DC-DC converter, which is preferably the reference potential GND. Reference symbol list 1 Low-voltage electrical system 11 first low-voltage partial electrical system 111, 112, 113 first low-voltage component 12 second low-voltage partial on-board network 121 second low-voltage component 123 Protection diode 13 third low-voltage sub-network 131 third low-voltage component 2 Vehicle electrical system 3 High-voltage electrical system 31 first high-voltage partial electrical system 311, 312, 313 first high-voltage components 32 second high-voltage partial on-board network 321 second high-voltage component 5 crash-proof area 7 Low-voltage vehicle battery 9 Protective disconnect switch device 91 semiconductor switches 93 Control unit 95 Measuring setup 97 Diode 99 limiting element CI30 first connection path CI31 second connection path

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