Battery-electric drive system for a motor vehicle and a method for monitoring the same

Abstract

The present invention relates to a battery-electric drive system for a motor vehicle having at least one HV battery and a plurality of electrical loads, having a multiplicity of electrical plug-in connections via which the electrical loads are at least indirectly connected to the at least one HV battery, having an HV interlock system for monitoring the state of the electrical plug-in connections, the HV interlock system comprising at least one controller and state monitoring devices which are assigned to the electrical plug-in connections and are designed to detect an at least partially released state of the plug-in connections, and the state monitoring devices being connected to the at least one controller via signal lines, the signal lines having supply lines and return lines which are contacted with one another via signal bridges of the electrical state monitoring devices, the signal bridges each extending between two plug-in connection partners of the electrical plug-in connections. The invention is characterized in that the electrical plug-in connections are combined to form a plurality of different functional groups, the signal bridges of the assigned state monitoring devices of which are each connected to the at least one controller via a common supply line and a common return line.

Description

[0001] Battery-electric propulsion system for a motor vehicle and method for monitoring such a system

[0002] The present invention relates to a battery-electric drive system for a motor vehicle comprising at least one high-voltage battery, hereinafter referred to as HV battery, and a plurality of electrical consumers, as well as a plurality of electrical connectors, via which the consumers are at least indirectly connected to the at least one HV battery, according to the preamble of claim 1. The invention further relates to a method for monitoring such a battery-electric drive system.

[0003] Vehicles with a battery-electric drive system contain numerous connectors through which the electrical components are connected to the high-voltage battery. To ensure safe operation, it is essential to monitor these connectors. This allows for the early detection of loose connections and prevents the risk of electric shocks or arcing.

[0004] A high-voltage interlock system is used to monitor the electrical connectors. This system monitors the correct condition of the electrical connectors in the high-voltage circuit. The system comprises a control unit and condition monitoring devices assigned to the electrical connectors. These devices are designed to detect when the electrical connectors are at least partially disconnected. The condition monitoring devices are connected to the control unit via signal lines. A signal bridge runs across each electrical connector and is connected to the control unit via a supply and return line. If the electrical connector is at least partially disconnected, the signal bridge on the connector is interrupted, which is then detected by the control unit.The control unit immediately opens the main HV relay and de-energizes the battery-electric drive system.

[0005] The signal lines, including supply lines, return lines, and signal bridges, are also referred to as pilot or safety lines. These can, for example, comprise a series circuit powered by the 12-volt vehicle electrical system, running from electrical connector to electrical connector. Pilot or safety contacts are present in all relevant electrical connectors, which may also include covers. For example, the connectors may also include a service disconnect.

[0006] Examples of such monitored electrical connectors can be found in EP 2 127039 B1.

[0007] An embodiment of an HV interlock system is disclosed in DE 102016210721 A1. Such an HV interlock connector system can also be used, for example, in the present invention.

[0008] Another embodiment of an HV interlock system is disclosed in US 2017 / 0292982 A1.

[0009] A disadvantage of the known embodiments is that when an electrical plug connection is detected to be at least partially disconnected, the entire battery-electric drive system is switched off.

[0010] The present invention is based on the objective of improving the availability of the battery-electric drive system while ensuring the operational reliability of the battery-electric drive system.

[0011] The problem according to the invention is solved by a battery-electric drive system for a motor vehicle, in particular for a bus, with the features of claim 1 and a method with the features of claim 11. The dependent claims describe advantageous and particularly expedient embodiments of the invention.

[0012] A battery-electric drive system according to the invention for a motor vehicle comprises at least one high-voltage battery and a plurality of electrical consumers. The electrical consumers are connected to the at least one high-voltage battery at least indirectly via electrical connectors. The battery-electric drive system further comprises a high-voltage interlock system for monitoring the state of the electrical connectors, wherein the high-voltage interlock system comprises at least one control unit and state monitoring devices associated with the electrical connectors, which are configured to detect an at least partially disconnected state of the connectors.

[0013] The condition monitoring devices are connected to the at least one control unit via signal lines. These signal lines comprise supply and return lines, which are connected to each other via signal bridges of the electrical condition monitoring devices. The signal bridges extend between two connector partners of the electrical connectors. The connector partners together form a plug connection by being plugged together.

[0014] According to the invention, the electrical connectors are grouped into several different functional groups, the signal bridges of which of the associated condition monitoring devices are each connected to the at least one control unit via a common supply line and a common return line.

[0015] By grouping the electrical connectors into individual, different functional groups, the electrical connectors of these functional groups can be monitored jointly, but separately from the electrical connectors of the other functional group(s) by at least one control unit.

[0016] The various functional groups can differ from one another in terms of the criticality of their electrical loads with regard to the operational safety of the battery-electric drive system. These loads are at least indirectly connected to the at least one high-voltage battery via the electrical connectors in the respective functional group. This makes it possible to disconnect the electrical loads whose electrical connectors are grouped together in a common functional group. A distinction can be made between whether only the electrical loads with the electrical connectors in the respective functional group need to be disconnected, or whether the entire battery-electric drive system needs to be shut down.The entire battery-electric drive system can be shut down if a partially disconnected electrical connection in a first functional group is detected, whereas only the consumers with electrical connections in a second functional group are shut down if a partially disconnected electrical connection is detected there. In the latter case, consumers with connections from another functional group or groups can continue to operate.

[0017] According to a preferred exclamation example of the invention, the battery-electric drive system comprises an electrical charging port with several electrical lines which are connected in parallel to each other, at least indirectly, via an electrical plug connection to the at least one HV battery.

[0018] According to one embodiment of the invention, the electrical consumers comprise at least one electric traction drive motor with several electrical connecting lines, which are connected in parallel to each other at least indirectly via an electrical plug connection to the at least one HV battery.

[0019] According to a further development of the invention, the electrical consumers comprise several auxiliary electrical consumers that are not permanently required for the operation of the battery-electric drive system and are connected at least indirectly to the at least one HV battery via electrical connecting lines with a plug connection, wherein the electrical plug connections in the electrical connecting lines are grouped into at least one functional group.

[0020] In the aforementioned embodiments, the battery-electric drive system preferably comprises a power distribution unit (PDU) or power distribution box (PDB), which includes connections for the electrical cables, the electrical connection cables, and the electrical connecting cables, wherein the connections are each formed by an electrical plug connection that is monitored according to the invention. This enables a particularly safe distribution of electrical power in the battery-electric drive system. The consumers whose electrical plug connections are grouped into a functional group are preferably able to be switched off together.

[0021] According to a preferred embodiment, the HV interlock system comprises a plurality of control units interconnected via a CAN bus, enabling them to communicate with each other over the CAN bus. The control units include a main control unit and several group control units, each group control unit being connected to the signal bridges of its respective functional group via a common input and return line.This allows the main control unit to generate interlock signals that are transmitted via the CAN bus to the group control units. Each group control unit modifies the interlock signals based on the state of the signal bridges connected to it and transmits them back to the main control unit via the CAN bus. The main control unit then determines, by comparing the interlock signals transmitted to and from the group control units, whether a signal bridge in a functional group is broken. Accordingly, the consumers whose electrical connections are grouped into that functional group can then be switched off simultaneously.

[0022] According to another embodiment, the group control units only need to implement the requirements of the main control unit by sending the signals from the main control unit via the supply lines to the signal bridges and sending the signals from the return lines to the main control unit. The main control unit then determines whether a fault condition exists, in particular a partially disconnected plug connection, by comparing the signals from its control of the group control units with the signals sent back by the group control units. The group control units can then be simple I / O gateways.

[0023] According to an alternative, equally advantageous embodiment of the invention, the HV interlock system comprises a main control unit and a group control unit, which are connected to each other via a CAN bus, enabling them to communicate with each other via the CAN bus. The group control unit is connected to the signal bridges of all functional groups via a common input and a common return line. Thus, a single group control unit performs the function of the previously described plurality of group control units.This allows the main control unit to generate interlock signals that are transmitted via the CAN bus to the group control unit. The group control unit modifies the respective interlock signals depending on the state of the signal bridges connected to it and transmits them back to the main control unit via the CAN bus. The main control unit then determines, by comparing the interlock signals transmitted to and from the group control unit for the respective group, whether a signal bridge in a functional group is broken. Accordingly, the consumers whose electrical connections are grouped together for that functional group can then be switched off simultaneously.

[0024] In one embodiment, the group control unit can also be a simple IO gateway that merely implements the requirements of the main control unit by sending the signals from the main control unit via the supply lines to the signal bridges and sending the signals from the return lines to the main control unit, which then determines whether a fault condition exists, in particular a partially disconnected state of a plug connection, by comparing the signals of its control of the group control unit and the signals sent back by the group control unit.

[0025] According to the inventive method for monitoring a battery-electric drive system, the condition monitoring devices detect the state of the electrical connectors, and if an at least partially disconnected state of an electrical connector is detected, electrical power transmission to this electrical connector is prevented.

[0026] When the electrical connector is detected as being at least partially disconnected, electrical power transmission to all electrical connectors that are grouped together in a functional group with this electrical connector, i.e., with the electrical connector whose partially disconnected state has been detected, is prevented.

[0027] As explained, preferably at least one first functional group is predefined, in which, upon detection of an at least partially disconnected state of an electrical connector in this functional group, the entire battery-electric drive system is switched off, and furthermore, at least one second functional group is predefined, in which, upon detection of an at least partially disconnected state of an electrical connector in this second functional group, only the electrical power transmission to all electrical connectors in this second functional group is interrupted, and the electrical power transmission to the electrical connectors of at least one other functional group is continued. In particular, an error message can be generated and output.

[0028] The second functional group preferably includes electrical connectors through which electrical auxiliary consumers are supplied with electrical power.

[0029] The invention makes it possible, depending on the criticality of the functional group, to either completely stop the operation of the battery-electric drive system and de-energize the HV system of the battery-electric drive system, or to switch off only the affected HV components, i.e. the corresponding electrical consumers, and, for example, generate a warning to the driver, even while the motor vehicle is in motion.

[0030] This has the advantage that, firstly, a more precise diagnosis of the electrical connectors can be achieved at the system level, and secondly, vehicle availability is increased because the auxiliary components—that is, electrical auxiliary consumers that are not permanently required for the operation of the vehicle—can be switched off. In particular, this allows for emergency operation of the battery-electric drive system for driving to the nearest workshop.

[0031] The invention will be explained below by way of example using embodiments and figures.

[0032] They show:

[0033] Figure 1 shows a first embodiment of a battery-electric drive system according to the invention; Figure 2 shows a modified embodiment with a main control unit and group control units that are connected to each other via a CAN bus;

[0034] Figure 3 shows a modified embodiment with a main control unit and a group control unit connected to each other via a CAN bus.

[0035] Figure 1 shows a battery-electric drive system according to the invention for a motor vehicle, comprising a high-voltage battery 1 electrically connected to a power distribution unit 12. Various electrical consumers 2, including an electric traction drive motor 10, auxiliary electrical consumers 11, and an electrical charging port 9, are also connected to the power distribution unit 12. The power distribution unit 12 distributes the electrical power of the high-voltage battery 1 to the various electrical consumers 2, in the illustrated embodiment therefore to the auxiliary consumers 11 and the electric traction drive motor 10. Furthermore, the power distribution unit 12 controls the charging of the high-voltage battery 1 via the electrical charging port 9. In this sense, the high-voltage battery 1 is also an electrical consumer 2 during the charging process.In bidirectional charging via the electrical charging port 9, the electrical charging port 9 can also represent an electrical consumer 2 that is supplied from the HV battery 1.

[0036] The various electrical components or electrical consumers 2 are connected to the power distribution unit 12, and thus indirectly to the high-voltage battery 1, via electrical connectors 4. Therefore, electrical power from the high-voltage battery 1 can be supplied to the auxiliary consumers 11 and the electric traction drive motor 10 via the power distribution unit 12, provided that the two connector partners 3.1 and 3.2 of the corresponding electrical connectors 3 are properly connected, i.e., the electrical connectors 3 are not at least partially disconnected. In this state, no electrical voltage can unintentionally escape from the interface between connector partners 3.1 and 3.2.The current state of the electrical connectors 3 is detected by condition monitoring devices 6, with one condition monitoring device 6 being provided for each electrical connector 3. In the illustrated embodiment, the condition monitoring devices 6 comprise signal bridges 7.3, which are closed when the electrical connectors 3 are properly closed and are interrupted when the electrical connectors 3 are at least partially disconnected.

[0037] The condition monitoring devices 6 are connected via signal lines 7 to a control unit 5 of an HV interlock system 4, wherein the signal lines 7 comprise supply lines 7.1 and return lines 7.2. The supply lines 7.1 and return lines 7.2 are electrically connected to each other via the signal bridges 7.3.

[0038] According to the invention, the electrical connectors 3 are divided into several different functional groups 8. In the illustrated embodiment, two electrical connectors 3, through which an auxiliary consumer 11 is supplied with electrical power, are combined into one functional group 8. Furthermore, the electrical connectors 3, through which two further auxiliary consumers 11 are supplied with electrical power, are combined into a common functional group 8. The electrical connectors 3, through which the high-voltage battery 1 is connected to the power distribution unit 12, are combined in one functional group 8, as are the electrical connectors 3, through which the electric traction drive motor 10 is connected to the power distribution unit 12.Finally, the electrical connectors 3, via which the electrical charging port 9 is connected to the power distribution unit 12, are grouped together in a functional group 8.

[0039] The parallel electrical lines connecting the electrical charging port 9 to the power distribution unit 12 are referred to as "electrical lines". The electrical lines connecting the electric traction drive motor 10 to the power distribution unit 12 are referred to as "electrical connection lines". The electrical lines connecting the auxiliary consumers 11 to the power distribution unit 12 are referred to as "electrical connecting lines".

[0040] By grouping the electrical connectors 3 into individual functional groups 8, depending on the relevance of the associated electrical consumers 2 for the operation of the battery-electric drive system, the electrical consumers 2 whose electrical connectors 3 are grouped in a common functional group 8 can be switched off together, or the entire battery-electric drive system can be switched off.

[0041] Figure 2 shows an embodiment of an HV interlock system 4 in a battery-electric drive system according to the invention, wherein the HV interlock system 4 comprises a main control unit 5.1 and a plurality of group control units 5.2, 5.3, which are interconnected via a CAN bus 13 to exchange control signals. Each group control unit 5.2, 5.3 is connected via a common supply line 7.1 and a common return line 7.2 to the signal bridges 7.3 of each functional group 8 connected in series, wherein the signal bridges 7.3 in turn each bridge two connector partners 3.1, 3.2.

[0042] The main control unit 5.1 generates interlock signals that are transmitted to the group control units 5.2 and 5.3. The group control units 5.2 and 5.3 detect the state of the signal bridges 7.3 and modify the interlock signals transmitted to them depending on the detected state. The modified interlock signal is then transmitted back to the main control unit 5.1, which compares the interlock signals transmitted to the group control units 5.2 and 5.3 with the interlock signals received back and determines whether the interlock loop, i.e., the signal bridge 7.3, has been interrupted.

[0043] Figure 3 shows an embodiment of an HV interlock system 4 in a battery-electric drive system according to the invention, wherein the HV interlock system 4 comprises a main control unit 5.1 and only one group control unit 5.2, which are connected to each other via a CAN bus 13 in order to exchange control signals. The group control unit 5.2 assumes the functions of the various group control units 5.2, 5.3 of the embodiment from Figure 2 and is connected via a common supply line 7.1 and a common return line 7.2 to the signal bridges 7.3 of the functional group 8 connected in series, wherein the signal bridges 7.3 in turn each bridge two connector partners 3.1, 3.2.

[0044] The main control unit 5.1 also generates interlock signals here, which are transmitted to the group control unit 5.2. The group control unit 5.2 detects the state of the signal bridges 7.3 and modifies the interlock signals transmitted to them depending on the detected state. The interlock signal modified according to this condition is transmitted back to the main control unit 5.1, which compares the interlock signals transmitted to the group control unit 5.2 for each function group 8 with the interlock signals transmitted back to it and determines whether the interlock loop, i.e., the signal bridge 7.3, has been interrupted. (Reference symbol list)

[0045] HV battery

[0046] electrical consumer

[0047] electrical connector connector partner connector partner

[0048] HV Interlock System

[0049] control unit

[0050] Main control unit, group control unit, group control unit, condition monitoring device, signal line

[0051] supply line

[0052] Return line

[0053] Signal bridge

[0054] Functional group

[0055] electric charging port, electric traction drive motor, auxiliary consumers, power distribution unit

[0056] CAN bus

Claims

Patent claims 1. Battery-electric drive system for a motor vehicle with at least one HV battery (1) and a large number of electrical consumers (2); with a multitude of electrical connectors (3) via which the electrical consumers (2) are at least indirectly connected to the at least one HV battery (1); with an HV interlock system (4) for monitoring the state of the electrical connectors (3), wherein the HV interlock system (4) comprises at least one control unit (5) and state monitoring devices (6) associated with the electrical connectors (3), which are configured to detect an at least partially disconnected state of the connectors (3), and the state monitoring devices (6) are connected to the at least one control unit (5) via signal lines (7), wherein the signal lines (7) have supply lines (7.1) and return lines (7.2) which are contacted with each other via signal bridges (7.3) of the electrical condition monitoring devices (6), wherein the signal bridges (7.3) each extend between two plug connection partners (3.1, 3.2) of the electrical plug connections (3); characterized by the fact that the electrical connectors (3) are grouped into several different functional groups (8), the signal bridges (3) of which are connected to the associated condition monitoring devices (6) via a common supply line (7.1) and a common return line (7.2) to the at least one control unit (5).

2. Battery-electric drive system according to claim 1, characterized in that the various functional groups (8) differ from one another in terms of the criticality of the electrical consumers (2) with regard to the operational safety of the battery-electric drive system, which are at least indirectly connected to the at least one HV battery (1) via the electrical connectors (3) in the respective functional group (8).

3. Battery-electric drive system according to one of claims 1 or 2, characterized in that the battery-electric drive system comprises an electrical charging port (9) with several electrical lines which are connected in parallel to each other at least indirectly via an electrical connector (3) to the at least one HV battery (1).

4. Battery-electric drive system according to one of claims 1 to 3, characterized in that the electrical consumers (2) comprise at least one electric traction drive motor (10) with several electrical connecting lines which are connected in parallel to each other at least indirectly via an electrical plug connection (3) to the at least one HV battery (1).

5. Battery-electric drive system according to one of claims 1 to 4, characterized in that the electrical consumers (2) comprise several auxiliary electrical consumers (11) which are not permanently required for the operation of the battery-electric drive system and are at least indirectly connected to the at least one HV battery (1) via electrical connecting lines with an electrical plug connection (3), wherein the electrical plug connections (3) are grouped together in the electrical connecting lines to form at least one functional group (8).

6. Battery-electric drive system according to claims 3, 4 and 5, characterized in that the battery-electric drive system comprises a power distribution unit (12) which includes connections for the electrical lines, the electrical connection lines and the electrical connecting lines, wherein the connections are each formed by an electrical plug connection (3).

7. Battery-electric drive system according to any one of claims 1 to 6, characterized in that the consumers (2), whose electrical connectors (3) are grouped into a functional group (8), can each be switched off together.

8. Battery-electric drive system according to any one of claims 1 to 7, characterized in that the HV interlock system (4) comprises a plurality of control units (5.1, 5.2, 5.3) which are interconnected via a CAN bus (13), wherein the control units (5.1, 5.2, 5.3) comprise a main control unit (5.1) and several group control units (5.2, 5.3) and the group control units (5.2, 5.3) are each connected to the signal bridges (7.3) of the respective functional group (8) via a common supply line (7.1) and a common return line (7.2).

9. Battery-electric drive system according to one of claims 1 to 7, characterized in that the HV interlock system (4) comprises a plurality of control units (5.1, 5.2) which are interconnected via a CAN bus (13), wherein the control units (5.1, 5.2) comprise a main control unit (5.1) and a group control unit (5.2) and the group control unit (5.2) is connected to the signal bridges (7.3) of the functional groups (8) via a common supply line (7.1) and a common return line (7.2).

10. Battery-electric drive system according to claim 8 or claim 9, characterized in that the main control unit (5.1) is configured to generate interlock signals which are transmitted via the CAN bus (13) to the group control unit(s) (5.2, 5.3), wherein the group control unit(s) (5.2, 5.3) modifies the interlock signals depending on the state of the signal bridges (3) connected to it / them and transmits them back to the main control unit (5.1) via the CAN bus (13), which determines, depending on a comparison of the interlock signals transmitted to and from the group control unit(s) (5.2, 5.3), whether a signal bridge (3) in a functional group (8) is interrupted.

11. Method for monitoring a battery-electric drive system according to any one of claims 1 to 10 comprising the following steps: Detecting the state of the electrical connectors (3) with the condition monitoring devices (6), wherein, if an at least partially disconnected state of an electrical connector (3) is detected, electrical power transmission to this electrical connector (3) is prevented; characterized in that When detecting the at least partially disconnected state of the electrical connectors (3), electrical power transmission to all electrical connectors (3) that are grouped together with this electrical connector (3) in a functional group (8) is prevented.

12. Method according to claim 11, characterized in that at least one first functional group (8) is predefined in which, upon detection of an at least partially disconnected state of an electrical plug connection (3) in this first functional group (8), the entire battery-electric drive system is switched off, and at least one second functional group (8) is predefined in which, upon detection of an at least partially disconnected state of an electrical plug connection (3) in this second functional group (8), only the electrical power transmission to the electrical plug connections (3) that are grouped together in this second functional group (8) is prevented and the electrical power transmission to the electrical plug connections (3) of at least one other functional group (8) is continued and, in particular, an error message is generated and output.

13. Method according to claim 12, characterized in that the electrical plug connections (3) are grouped together in the second functional group (8), via which electrical auxiliary consumers (11) are supplied with electrical power.

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