Vehicle electrical system with a high-voltage section and a plurality of low-voltage sections connected to one another by means of a safety device

Abstract

A vehicle on-board electrical system (FB) is equipped with a high-voltage region (HV), a first low-voltage section (N1) extending from the high-voltage region (HV), a second low-voltage section (N2) and a safety device (S). The safety device (S) connects the first low-voltage section (N1) with the second low-voltage section (N2). The safety device (S) has an electrically isolating component (T) or a voltage-limiting element (SB).

Description

Technical Field

[0001] A vehicle-mounted electrical grid has a high-voltage section and a plurality of low-voltage sections extending from the high-voltage section, the low-voltage sections being interconnected by safety devices. Background Technology

[0002] Vehicles equipped with electric traction drive systems are known to use high-voltage batteries as their power source. To protect vehicle users, connections with high-voltage potentials are insulated and, where necessary, have additional protective measures. An insulation monitor is typically used to detect the insulation resistance of the high-voltage potential relative to the vehicle's ground wire, allowing for further action if the insulation value is too low. Because the contact voltage under fault conditions can be very high and poses a significant danger to users, the task is to make vehicles with high-voltage onboard electrical systems safer. Summary of the Invention

[0003] It is recognized that high-voltage components, i.e., components carrying high voltage potential during normal operation, can be electrically isolated from users through insulation and corresponding enclosures to ensure high safety. However, in the space where these high-voltage components are located, there are also low-voltage components and low-voltage lines derived from the high-voltage vehicle electrical grid. If a fault occurs in the high-voltage area, causing these low-voltage lines to carry high voltage potential, there is a higher risk of electric shock because the low-voltage lines are not insulated and protected to the same extent as the high-voltage lines. Therefore, it is proposed that a first low-voltage section extending from the high-voltage area be connected to a safety device, and a second low-voltage section extend away from this safety device. The safety device can ensure, through measures such as electrical isolation components or voltage limiting elements, that in the event of an insulation failure between the first low-voltage section and the high-voltage area, the dangerous voltage does not propagate to the other side of the safety device, thus preventing the dangerous voltage from reaching the second low-voltage section. This allows for the delimitation of an additional area (which, despite operating at low voltage under fault-free conditions, is still at risk of high voltage) to protect against external intrusion (Zugriff), while the second low-voltage section is further protected by safety devices against high voltage in the event of a fault. Therefore, the invention takes into account that the first low-voltage section can also carry high voltage in the event of a fault in the high-voltage area. It is proposed that the propagation paths of these dangerous voltages be blocked by safety devices to achieve greater safety for the second low-voltage section against high voltage that could propagate from the high-voltage area to the first low-voltage section due to a fault.

[0004] Therefore, a vehicle-mounted electrical network is described, comprising a high-voltage region, a first low-voltage section, and a second low-voltage section. The first low-voltage section extends from the high-voltage region. The low-voltage section specifically refers to the physical section containing low-voltage components and / or low-voltage lines. The second low-voltage section does not extend directly from the high-voltage region but is (indirectly) connected to the first low-voltage section. In the event of an insulation fault, the first low-voltage section can be provided with a high-voltage potential from the high-voltage region. To prevent the associated high-voltage potential from also affecting the second low-voltage section, the vehicle-mounted electrical network includes a safety device. This safety device connects the second low-voltage section to the first low-voltage section. There is no additional (electrical conduction) connection between the second low-voltage section and the first low-voltage section.

[0005] Therefore, the safety device can prevent the corresponding dangerous high-voltage potential extending from the high-voltage area into the first low-voltage section from reaching the second low-voltage section. Thus, the second low-voltage section is protected by the safety device from the high-voltage potential transmitted from the high-voltage area to the first low-voltage section due to insulation failure. The safety device has an electrical isolation component and / or a voltage limiting element. The electrical isolation component is thus located inside the safety device, between the first and second low-voltage sections. The voltage limiting element is positioned between the potential of the first and / or second low-voltage sections and the dissipation potential (such as ground or chassis) and is activated when the relevant low-voltage section has a voltage higher than the voltage limit relative to the dissipation potential. The safety device can also have both of the aforementioned safety measures.

[0006] Specifically, the safety device also physically separates the second low-voltage section from the first low-voltage section. Preferably, the safety device is located between the first and second low-voltage sections and forms a safety area extending between the first and second low-voltage sections. These areas can be defined by a limiting member such as a housing.

[0007] In one embodiment, the first low-voltage section includes all low-voltage lines extending from the high-voltage section. The second low-voltage section includes all lines and / or components functionally (i.e., particularly in the manner of signal transmission or power transmission) connected to the associated lines and / or components of the first low-voltage section. Multiple safety devices can be provided, each connected to a portion of the first low-voltage lines. Preferably, all low-voltage lines extending from the high-voltage section are connected to one of the safety devices, such that all such low-voltage lines are also protected or terminated at the safety device.

[0008] The vehicle's onboard electrical system can include low-voltage devices, such as control devices for operating components in high-voltage areas or control devices for detecting sensor data from high-voltage areas. Furthermore, the low-voltage devices can include communication devices, such as bus communication modules, particularly CAN bus slaves or CAN bus masters. The low-voltage devices can also be displays (e.g., voltage displays or display devices that can also display the voltage in the high-voltage area) or input devices that are functionally or signal-transmitted to components in the high-voltage area. Additionally, the low-voltage devices can be low-voltage power supplies that provide low-voltage voltage to components in the high-voltage area (via a first low-voltage section and a second low-voltage section).

[0009] The low-voltage device is connected to the second low-voltage section. The second low-voltage section connects the low-voltage device to the safety device. The low-voltage section is located between the low-voltage device and the safety device. The low-voltage device is connected to the first low-voltage section via the second low-voltage section and the safety device connected thereto. This leads to the high-voltage area. Therefore, the first low-voltage section, the safety device, and the second low-voltage section (especially starting from the high-voltage section in this order) are located between the low-voltage device and the high-voltage area. The low-voltage device is connected to the high-voltage area or to components located within the high-voltage area via the second low-voltage section, the safety device, and the first low-voltage section for signal transmission and / or power supply. These components are especially low-voltage components located within the high-voltage area. Here, the signal transmission connection represents an electrically isolated data connection. Furthermore, the power supply connection can also be electrically isolated, more precisely, through the safety device having an electrically isolated component in the form of a transformer (electrical isolation). Electrical isolation components can be provided, for example, by a transformer with electrical isolation for safety devices, connected to a first low-voltage section on one side (e.g., the primary side) and to a second low-voltage section on the second side (the secondary side). Alternatively, an optocoupler can be used as an electrical isolation component, connecting the two low-voltage sections to each other for signal transmission. The aforementioned transformer can be a transformer for transmitting signals, or a transformer for transmitting power, or both (e.g., in the case of power line communication).

[0010] The low-voltage section has wiring, particularly signal lines, communication lines, sensor lines, and / or low-voltage power supply lines. These lines are designed for operating voltages below 60 V and therefore lack high-voltage insulation. The insulation of the lines is specifically designed for low-voltage applications rather than high-voltage applications. The first low-voltage section has wiring connecting one or more low-voltage components in the high-voltage area to a safety device. This connection is conductive. Therefore, in the event of a fault in the high-voltage area, the wiring of the first low-voltage section can have a high-voltage potential, which is at most directed to the safety device. The safety device then blocks the high-voltage potential. The second low-voltage section also has wiring connected to the safety device. The wiring of the second low-voltage section is thus connected to the wiring of the first low-voltage section via the safety device. The connection thus established by the safety device is electrically isolated. Therefore, signal lines are connected to data transmission devices via electrically isolated transformers or preferably via optocouplers. Low-voltage power supply lines can be connected via electrically isolated transformers. The safety device connects each line of the first low-voltage section to the corresponding line of the second low-voltage section in an electrically isolated manner. Each line in the first low-voltage section has a corresponding portion in the second low-voltage section, such that each low-voltage line in the first low-voltage section located in the high-voltage area has a corresponding portion in the second low-voltage section. These lines can be implemented as wire and / or conductor circuits, particularly wire and / or conductor circuits of flexible foil circuit boards. The vehicle's onboard electrical network particularly includes one or more low-voltage devices connected to safety devices via the second low-voltage section. As previously mentioned, the low-voltage devices can be displays, control devices, HMI devices, input terminals, or similar devices. The low-voltage devices can particularly be located in or near spaces easily accessible to the user, such as the vehicle interior, engine compartment, luggage compartment, etc.

[0011] On the other hand, the two low-voltage sections are spatially separated by safety devices. One aspect is specifically placing the first low-voltage section (which carries a high voltage potential in the event of a fault) in a first space that is not easily accessible to the user. Therefore, it is possible to arrange the first low-voltage section in a first space protected by a continuous barrier against external access (by the vehicle user). This continuous barrier can be provided by a cover or similar object that cannot be opened by the user during normal vehicle use and requires tools to open. This ensures that the user cannot enter the low-voltage section during normal vehicle use, thus preventing accidental contact. The continuous barrier for the low-voltage section can be provided by a plastic or metal (grounded) cover, and by a wall that completely surrounds the space together with the cover. These walls preferably have no openings or only openings that can only be opened with tools and are not easily opened. In short, the first space is closed and cannot be opened during normal operation, especially without tools.

[0012] The second low-voltage section is disposed in the second space. This second space can be open and, in particular, freely accessible from the outside. The second space is easily accessible to the user during normal use, especially from the engine compartment, passenger compartment, and luggage compartment. For example, a 12V battery or 12V equipment in the engine compartment can be disposed in the second space. These components can be accessed without tools when the engine hood is opened. In particular, there is not necessarily a cover that seals off the second space and thus prevents its access without tools. Preferably, the safety device is disposed in its own housing. This housing is located between the first and second spaces. The first space is directly adjacent to its own housing. Preferably, the second space is also adjacent to the housing of the safety device; however, the first space and the second space remain isolated. This physical separation of the first and second spaces enables effective protection by the safety device.

[0013] Another feasible approach is to house the safety device within a housing located in the first space. This housing, in particular, can be situated on the inner side of the first space. Specifically, it can be the inner side of the outer wall of the first space or the outer wall of the limiting element of the first space. Thus, the second low-voltage section can be guided through the wall constituting the inner side or through the outer wall for connection to the safety device. Since the safety device is located directly on the outer wall of the first space, this ensures that the second low-voltage section is not connected to the first low-voltage section. The safety device can also be housed in a housing located on the inner side of the outer wall of a high-voltage housing, in which both a high-voltage region and a first low-voltage section are located. This is particularly suitable for the entire first low-voltage section, which is physically separated from and electrically isolated from the entire second low-voltage section by the safety device.

[0014] In embodiments where the safety device has at least one voltage limiting element, this voltage limiting element can be positioned between the low-voltage potential or line and the dissipation potential in the first and / or second sections. In this case, when the voltage in the first low-voltage section is too high, the associated current is drawn to the dissipation potential. The dissipation potential is particularly the ground wire or chassis. The voltage limiting element can be implemented as a rheostat, gas discharge tube, spark gap, protection diode, thyristor circuit, TVS thyristor, DIAG, Zener diode, or suppressor diode or quad-layer diode.

[0015] Multiple voltage limiting elements can be incorporated into a safety device to protect low-voltage potentials from the effects of different polarities of high-voltage voltages or to protect multiple lines. When using voltage limiting elements, the two low-voltage sections are not necessarily electrically isolated. Instead, it can be specified that the lines in the first low-voltage section are conductively coupled to the lines in the second low-voltage section when using voltage limiting elements. However, by connecting the safety device between the two low-voltage sections, it becomes possible to reduce or limit the voltage by activating the voltage limiting element when an excessively high voltage occurs in the first low-voltage region.

[0016] The second low-voltage section remains protected by allowing the current generated by excessive voltage in the first low-voltage section to flow away. A resistor or similar component can be incorporated into the safety device to connect the lines of the first and second low-voltage sections, wherein a voltage-limiting element is preferably located at the end of the line in the second low-voltage section connected to the associated resistor. The maximum transmittable current is then limited by the resistors connecting the two low-voltage sections in series, and simultaneously, in the event of excessive current (due to a high-voltage fault), the current limited by the resistors is drawn to a reference potential. The resistors connecting the two low-voltage sections are preferably designed such that the line can fulfill its function in fault-free operation, i.e., the line is configured to transmit signals or power supply voltage.

[0017] As previously mentioned, the vehicle's onboard electrical system can have low-voltage devices connected to safety devices via a second low-voltage section. These low-voltage devices can provide sensor detection, control, communication, or monitoring functions, referring to low-voltage components located within a high-voltage area. Therefore, the low-voltage devices are located outside the high-voltage area but functionally connected (to data transmission ground and / or power supply voltage transmission ground) to low-voltage components located within the high-voltage area. The low-voltage devices themselves can be located in spaces easily accessible to the user during normal use. This applies, for example, to operating elements of HMI interfaces or displays located on the dashboard or typically in the passenger compartment. It also applies to low-voltage devices located in the engine compartment (or luggage compartment) and easily accessible to the user when in proper use (after opening the relevant passenger compartment door, luggage compartment cover, or engine compartment cover).

[0018] The safety device preferably has a fault output terminal. The safety device is configured to output a high-voltage fault to the fault output terminal when the voltage in at least one of the low-voltage sections exceeds a voltage limit. This also applies to voltages present only on conductors within the mentioned sections. Voltage refers to dissipated potentials such as ground or chassis. The voltage limit is preferably less than 60V, for example, 50, 40, 35, or 25V. The voltage limit is higher than the maximum level of all lines in the low-voltage section during fault-free operation. The vehicle's onboard electrical system can have a discharge or disconnect device functionally connected to the fault signal output terminal. In this case, appropriate measures (discharge and / or disconnection) can be performed when a high-voltage fault occurs at the fault signal output terminal (in the form of a signal). A high-voltage fault exists when the voltage in the low-voltage region exceeds, for example, a voltage limit of 60V DC or 30Vrms AC.

[0019] The prefix "High Voltage" indicates that, especially when insulated, the relevant components are designed for operating voltages greater than 60 V, at least 100 V, at least 200 V, at least 400 V, at least 600 V, or at least 800 V. The prefix "Low Voltage" indicates that, especially when insulated, the relevant components are designed for operating voltages less than 60 V, not greater than 48 V, or not greater than 24 V, or 12 V. These voltage specifications refer to DC voltage, but can also refer to the effective voltage level or amplitude of AC voltage.

[0020] Motor vehicles equipped with a pure electric drive system or a hybrid drive system (which includes an electric drive system) can have the vehicle-mounted electrical network described herein. A high-voltage traction battery and a high-voltage traction drive system can be installed in the motor vehicle, both connected to the high-voltage area of ​​the vehicle-mounted electrical network described herein. Thus, the high-voltage traction battery and the high-voltage traction drive system are preferably part of the vehicle-mounted electrical network described herein. Attached Figure Description

[0021] Figure 1 This is used to illustrate the objects described herein. Detailed Implementation

[0022] Figure 1 A high-voltage region HV is shown, in which at least one high-voltage component HVK is present. The high-voltage region is enclosed by a high-voltage housing. Furthermore, a low-voltage component K is also present in the high-voltage region, from which the line L1 of a first low-voltage segment N1 originates. The low-voltage segment N1, and its line L1, thus extend from the high-voltage region HV, originating from the low-voltage component (within the high-voltage region). The first low-voltage segment N1 surrounds a space R1, which, under proper use, cannot be accessed by the vehicle user from the outside. For this purpose, for example, a cover A can be provided that encloses the first space R1 of the low-voltage segment N1. In this case, the cover A encloses the space R1 so that the user cannot access the space R1 without tools or under proper use.

[0023] Safety device S is connected to a first low-voltage region N1. This safety device has a housing G. A second low-voltage section N2, having line L2, is also connected to safety device S. These form a low-voltage device located outside the high-voltage region. Therefore, low-voltage device NG is functionally connected to low-voltage component K (located within the high-voltage region HV). Thus, low-voltage component K can communicate with, be powered by, and / or be controlled by low-voltage device NG. Furthermore, component K can also transmit data, such as sensor data, to the low-voltage device.

[0024] To protect the second low-voltage section N2 from excessive voltage (which can occur when a high voltage in the high-voltage section HV reaches line L1 of the first low-voltage section N1), the safety device S includes an electrical isolation component T and / or a voltage limiting element SB. In the case of the electrical isolation component T, an optocoupler and / or an electrical isolation transformer may be used, for example. The electrical isolation component T is only symbolically shown by means of a dashed line, which defines electrical isolation as a functional characteristic. An exemplary example of the voltage limiting element SB is a rheostat that connects the line within the safety device S to a reference potential or dissipated potential M (ground). If an excessively high voltage relative to ground is applied to the relevant line, the voltage limiting element SB activates and dissipates the relevant current towards ground. This protects the second low-voltage section N2 from excessive voltage. Specifically, the safety device S can detect the current flow through the voltage limiting element SB to infer a high-voltage fault based on the current flow. This fault is then sent as a signal to the fault signal output terminal F of the safety device S. The isolation component T physically prevents high voltage from reaching the second low voltage region N2, while the voltage limiting element SB not only reduces high voltage caused by faults but also detects high voltage faults. Even with only the electrical isolation component T installed, the potential of line L1 in the first low voltage section N1 can be monitored so that a corresponding fault signal can be sent to the fault output terminal F when the voltage limit is exceeded. A safety device S is therefore provided.

Claims

1. A vehicle-mounted electrical network (FB) comprising: a high-voltage region (HV), a first low-voltage section (N1) extending from the high-voltage region (HV), a second low-voltage section (N2), and a safety device (S) connecting the first low-voltage section (N1) and the second low-voltage section (N2), wherein, The safety device (S) has an electrical isolation component (T) or a voltage limiting element (SB). The first low-voltage section (N1) is disposed in a first space (R1), which is protected from external entry by a continuous limiting member (B), and the second low-voltage section (N2) is disposed in a second space (R2), which is freely accessible from the outside, and the safety device (S) is disposed in its unique housing (G), which is located between the first space (R1) and the second space (R2), or on the inner side (I) of the outer wall of the limiting member (B) of the first space (R1).

2. The vehicle-mounted electrical network according to claim 1, further comprising at least one low-voltage device (NG), the at least one low-voltage device being connected to a second low-voltage section (N2) and connected to a low-voltage component (K) in the high-voltage region (HV) via the second low-voltage section (N2), a safety device (S) and a first low-voltage section (N1) in a manner of signal transmission and / or voltage supply.

3. The vehicle-mounted electrical network according to claim 1 or 2, wherein, The first low-voltage section (N1) has a line (L1) that connects the low-voltage component (K) in the high-voltage region (HV) to the safety device (S); and the second low-voltage section (N2) has a line (L2) that connects to the safety device (S).

4. The vehicle-mounted electrical network according to claim 1, wherein, The safety device (S) has a voltage limiting element (SB), and the voltage limiting element (SB) has a rheostat, a gas discharge tube, a spark gap, a protection diode, a thyristor circuit, a TVS thyristor, a DIAC, a Zener diode, a suppression diode and / or a four-layer diode.

5. The vehicle-mounted electrical network according to claim 1, wherein, The second low-voltage section (N2) connects the safety device (S) to at least one low-voltage device (NG), which has a sensor detection device for the low-voltage component (K), a control device for the low-voltage component (K), a wired communication device for communicating with the low-voltage component (K), or a monitoring device for the low-voltage component (K), wherein the low-voltage component (K) is arranged in the high-voltage region (HV).

6. The vehicle-mounted electrical network according to claim 1, wherein, The safety device (S) has a fault signal output terminal (F), and the safety device (S) is configured to output a high voltage fault at the fault signal output terminal (F) and send it to the superior vehicle control device when the result of the voltage measuring device / voltage monitoring device of the safety device (S) in at least one low voltage segment (N1, N2) exceeds the voltage limit.

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