Control device and method for actively reducing a voltage in a high-voltage system

Abstract

The present invention relates to a control device (2) for operating a battery-powered electric motor vehicle (1) after an accident situation. The control device (2) is designed to disconnect a high-voltage storage unit (4) of the motor vehicle (1) from a high-voltage system comprising high-voltage components at all poles after the accident situation; after the high-voltage storage unit (4) has been disconnected, the control device is designed to detect a remaining voltage on a Y-path of the high-voltage system by means of a measuring device as a function of the state of the measuring device, the measuring device having an active and an inactive state. The control device (2) is designed to switch the measuring device to the active state and to couple it to the Y-path in order to actively reduce the remaining voltage detected in the Y-path.

Description

[0001] Control device and method for actively reducing a voltage in a high-voltage system

[0002] The present disclosure relates to a control device for operating a battery-electric motor vehicle after an accident situation and / or a method for controlling the operation of a battery-electric motor vehicle after a fall. Additionally or alternatively, a computer program is provided that includes instructions that, when executed by a computer, cause the computer to at least partially execute the method. Additionally or alternatively, a computer-readable medium is provided that includes instructions that, when executed by a computer, cause the computer to at least partially execute the method.

[0003] Driver assistance systems can incorporate functions to restore BEVs (battery electric vehicles) and PHEVs (plug-in hybrid vehicles) to a safe and / or non-critical system state in hazardous and / or accident situations. In existing BEV and PHEV vehicles, electrical energy may still be present in the high-voltage (HV) system after an accident and subsequent activation of the accident safety precautions. A voltage may still be present between the poles of the HV system and the vehicle body. Knowing whether voltage is present at the body or whether the vehicle is de-energized after an accident is important for rescue workers and other persons who must provide assistance or recover a BEV after an accident.

[0004] The known systems do not feature any active discharge of the live motor vehicle in their technical implementation. Rather, the HV system is designed in such a way that it can survive an accident without damage and thus no voltage can be applied to the body that would endanger third parties. However, designing the HV system without damage is complex in terms of technical implementation. Furthermore, a discharge of Y capacitors can be provided. US2020 / 0127469A1 proposes a battery module for use in an electric vehicle. The battery module comprises a power source and an insulation monitoring circuit that is electrically connected to the power source. The electric vehicle comprises a Y capacitor module. The insulation monitoring circuit can discharge the Y capacitor module when the battery module is electrically connected to the electric vehicle.The insulation monitoring circuit in the battery module is used as a discharge device to discharge the Y capacitor when the energy content of the Y capacitor is greater than the predetermined threshold.

[0005] Against the background of this prior art, the object of the present disclosure is to provide a device and / or a method which are each suitable for enriching the prior art.

[0006] The problem is solved by the features of the independent claims. The subordinate claims and the dependent claims each contain optional developments of the disclosure.

[0007] According to this, the problem is solved by a control device for operating a battery-electric motor vehicle after an accident situation. The control device is designed to disconnect a high-voltage storage device of the motor vehicle from a high-voltage system comprising high-voltage components across all poles after the accident situation. Furthermore, the control device is configured to detect, after the high-voltage storage device has been disconnected, a remaining voltage on a Y-path of the high-voltage system by means of a measuring device as a function of the state of the measuring device, wherein the measuring device has an active and an inactive state. Furthermore, the control device is designed to switch the measuring device to the active state and to couple it to the Y-path in order to actively reduce the detected voltage remaining in the Y-path.

[0008] The control device or control unit can be part of the driver assistance system or represent it. The control device can be, for example, an electronic control unit (ECU). The electronic control unit can be an intelligent processor-controlled unit that can communicate with other modules, for example, via a central gateway (CGW) and, if necessary, can form the vehicle's on-board network via fieldbuses such as the CAN bus, LIN bus, MOST bus, FlexRay, and / or via the automotive Ethernet, e.g., together with telematics control units and / or environmental sensors.

[0009] It is conceivable that the control device controls functions relevant to the driving behavior of the motor vehicle, such as the steering, engine control, power transmission, energy management, and / or the braking system. Furthermore, driver assistance systems such as a parking assistant, adaptive cruise control (ACC), lane keeping assistant, lane change assistant, traffic sign recognition, traffic light recognition, start-off assistant, night vision assistant, and / or intersection assistant can be controlled by the control device. Furthermore, the control device can provide control signals for controlling other components of the motor vehicle and / or for controlling switching components.

[0010] For the purposes of the disclosure, an accident situation with respect to a battery electric vehicle (BEV) may refer to a situation in which the BEV is involved in a collision, impact, or other incident that may have resulted in damage to the motor vehicle. In an accident situation, the BEV may sustain damage due to an external force, such as impact with another vehicle, collision with an obstacle, or other circumstances. This may result in damage to the body, drive components, HV system, high-voltage storage (HV storage), and / or other systems of the motor vehicle. In an accident situation, specific risks related to the high-voltage system may exist. In a collision, there may be a possibility of damage to high-voltage components, such as the high-voltage storage, cables, or control units.This damage can lead to leaks, short circuits, or other electrical hazards. Furthermore, in the event of serious damage to the vehicle, there is a potential risk of thermal runaway of the high-voltage battery. This refers to uncontrolled overheating or ignition of the high-voltage battery due to damage or malfunction. In an accident situation, it can be critical that specific procedures for protecting the high-voltage system are observed and implemented to minimize the risk of injury or further damage.

[0011] For the purposes of the present disclosure, a high-voltage storage system in a battery electric vehicle (BEV) may consist of or include multiple battery modules or cell packs, which may be connected in series to generate a higher total voltage. Each battery module may contain multiple battery cells. The number of terminals in a high-voltage storage system may depend on the type of battery cells and the configuration of the system. Common lithium-ion batteries have two terminals: a positive (+) terminal and a negative (-) terminal. The total number of terminals may depend on the number of battery modules connected in series. The voltage between the terminals of a high-voltage storage system can be very high, ranging from several hundred volts to thousands of volts, depending on the battery system and configuration.

[0012] For the purposes of the present disclosure, the all-pole disconnection of a high-voltage storage device may refer to the process of simultaneously disconnecting all poles of the high-voltage storage device to ensure that no electrical voltage or current flow remains between the high-voltage components. This is an important safety mechanism that allows working on high-voltage components in electric vehicles or towing the vehicle without the risk of electric shock. The all-pole disconnection may be performed using a switch or a fuse device. These switches or fuses may be designed to interrupt the electrical circuit between all poles of the high-voltage storage device.

[0013] For the purposes of this disclosure, the "Y-path" refers to the electrical path or connection leading from the high-voltage storage system to the drive motors. The high-voltage system in a BEV may include the high-voltage storage system, electrical cables, connectors, contactors, inverters, and / or the drive motors. The Y-path is a part of the system in which the high-voltage storage system provides electrical power to the drive motors. The "Y-path" optionally refers to the phased arrangement of the components. In this configuration, the high-voltage storage system can be considered the starting point from which electrical cables or busbars lead in a Y-shaped distribution to the drive motors. The Y-path can enable efficient distribution of electrical power from the high-voltage storage system to the drive motors as the main path for electrical current flow and can include various contactors, inverters, or other control components.

[0014] The device described above offers a number of advantages. Among other things, the control device according to the disclosure can ensure that the HV system and the HV components are de-energized after the high-voltage storage unit is disconnected. Furthermore, any remaining voltage in the HV system and / or the HV components can be reduced more quickly, so that the vehicle can be safely recovered by third parties after an accident.

[0015] Possible further developments of the device described above are explained in detail below.

[0016] It can be provided that the measuring device comprises an insulation monitoring device. Furthermore, it can be provided that the measuring device comprises an insulation monitor. The insulation monitor can be a safety mechanism in a BEV or PHEV that monitors the insulation integrity of the high-voltage system. It can detect possible insulation faults or reductions in insulation resistance and, in certain situations, trigger a shutdown of the high-voltage system to ensure and / or restore safety. The state or position of the insulation monitor at the shutdown moment refers to the point in time at which the insulation monitor detects the insulation fault or reduction in insulation integrity and initiates the shutdown of the system. Depending on the specific configuration of the high-voltage system and the insulation monitor, the voltage present in the system at the time of shutdown can vary.If the insulation monitor detects an insulation fault early and initiates shutdown of the RF system, the voltage in the RF system may be relatively low. On the other hand, if the insulation monitor detects an insulation fault late or not at all, the voltage in the system may be higher at the time of shutdown. The voltage level at the moment of shutdown can have various consequences, including the potential risk of electric shock or compromised safety of other high-voltage components.

[0017] An insulation monitoring device (IMD) is a device or system used in electrical systems or equipment to monitor the integrity of the electrical insulation. It can be used to detect potential insulation faults or leakage currents that may occur and cause potential hazards. The IMD can operate based on insulation resistance, which measures the degree of insulation between the conductive parts and ground potential. It can continuously monitor the insulation resistance and compare it to a predefined threshold. If the insulation resistance falls below this threshold, an optional alarm is triggered or a protective measure is initiated. The IMD can be used in high-voltage systems, such as those used in battery electric vehicles (BEVs).It is used to detect potential insulation faults in high-voltage components, such as batteries, inverters, cables, or connectors. Optional insulation monitoring devices ensure that electrical systems are properly insulated and the safety of third parties and equipment is guaranteed. Upon detection of an insulation fault, the insulation monitoring device can optionally trigger various protective measures, including circuit shutdown, an alarm, and / or an error message.

[0018] It can be provided that reducing the voltage includes discharging Y capacitors of the high-voltage components. In addition to the high-voltage storage device and / or other energy storage devices (fuel cell) for providing the supply energy, further energy storage devices are provided in the high-voltage system which optionally cannot be switched off by switching elements but must be discharged. These optionally cannot be separated from the on-board electrical system via switching elements, as this would be technically too complex. These smaller energy storage devices can be capacitors that can be provided directly in the HV components for buffering energy (so-called X capacitances) or for interference suppression (Y capacitors). The Y capacitors capacitively couple the respective HV components to the electrical ground of the vehicle. In addition, high-ohm insulation resistors are installed between the high-voltage on-board electrical system and ground.An accelerated reduction of the voltage by discharging the Y capacitors can increase the safety of third parties in the vehicle.

[0019] It can be provided that the coupling of the measuring device includes coupling to the high-voltage negative side of the Y-path. This can optionally accelerate the voltage reduction in the Y-capacitors of the high-voltage components.

[0020] It can be provided that the high-voltage system is separated from the high-voltage storage device via controllable switching elements, and that the switching elements are monitored via switching element sticking detection. For the purposes of the present disclosure, the controllable switching elements can be designed as contactors. Alternatively or additionally, further / other components can be provided via which a corresponding voltage and / or currents can be switched to operate the high-voltage system. Switching element sticking detection refers to a function or system in a battery electric vehicle (BEV) that serves to monitor the condition or integrity of the switching elements and to maintain a verifiable switching state and to detect potential problems at an early stage.

[0021] It can be provided that the switching elements have at least one switching-element-bridging resistance element. A switching-element-bridging resistance element is used in switching elements to limit the current flow through the contactor coil when the switching element is not actuated. It can be connected in parallel with the switching element coil. The main function of the switching-element-bridging resistance element can be to prevent the occurrence of switching sparks and to increase the service life of the switching element. Furthermore, sticking (welding) of the switching units (NC contacts, NO contacts, CO contacts) in the switching element should be detected and / or prevented.

[0022] The above description can be summarized in other words and in a possible more concrete embodiment of the disclosure as described below, whereby the following description is not to be interpreted as limiting the disclosure.

[0023] In BEV vehicles, a voltage may remain between the HV poles and the vehicle body after a crash shutdown in the HV system. The present disclosure aims to resolve this and accelerate its dissipation. In known systems, the HV system is not actively discharged because the corresponding manufacturers have designed the HV system to be damage-free in a crash. This can potentially lead to problems during homologation. Because voltage remains on the y-path after a crash shutdown of the HV system (all-pole disconnection of the HV storage device from the HV system and rapid discharge on the system side), this voltage must be discharged. The level of the voltage depends on the position of the insulation monitor at the moment of shutdown.Since the contactor sticking detection is designed to be triggered by contactor bridging resistors, the vehicle's Y-path can be actively discharged by actively positioning the insulation monitor on the HV negative side. This can be implemented by appropriate control using a computer program.

[0024] Furthermore, a motor vehicle with the control unit or control device described above is provided.

[0025] The motor vehicle may be a passenger car, in particular an automobile, or a commercial vehicle, such as a truck.

[0026] The motor vehicle may be automated. The motor vehicle may be configured to at least partially and / or at least temporarily assume longitudinal and / or lateral guidance during automated driving of the motor vehicle by means of the control device.

[0027] Automated driving can be implemented in such a way that the motor vehicle's movement is (largely) autonomous. Automated driving can be controlled at least partially and / or temporarily by the control device.

[0028] It is conceivable that the motor vehicle intervenes in the lateral guidance of the motor vehicle through a driver assistance system actively, e.g. by adjusting an actual steering wheel position, and optionally passively, e.g. by displaying a turn-off instruction.

[0029] The motor vehicle may be a motor vehicle with autonomy level 0, i.e. the driver assumes the dynamic driving task, even if supporting systems (e.g. ABS or ESP) are present.

[0030] The motor vehicle may be a Level 1 autonomy motor vehicle, i.e. it may have certain driver assistance systems that support the driver in operating the vehicle, such as adaptive cruise control (ACC).

[0031] The motor vehicle may be a motor vehicle of autonomy level 2, i.e. be so partially automated that functions such as automatic parking, lane keeping or lateral guidance, general longitudinal guidance, acceleration and / or braking are taken over by driver assistance systems.

[0032] The motor vehicle can be a Level 3 autonomy vehicle, meaning it is so conditionally automated that the driver does not need to continuously monitor the vehicle's system. The vehicle performs functions such as activating the turn signal, changing lanes, and / or keeping in lane independently. The driver can attend to other activities but will be prompted by the system to take over driving if necessary, within a pre-warning period.

[0033] The motor vehicle can be a Level 4 autonomy vehicle, meaning it can be so highly automated that the vehicle's control system permanently assumes control of the vehicle. If the system can no longer handle the driving tasks, the driver can be requested to take over.

[0034] The motor vehicle can be a Level 5 autonomy vehicle, meaning it can be so fully automated that the driver is not required to perform the driving task. No human intervention is required other than setting the destination and starting the system. The motor vehicle can operate without a steering wheel or pedals.

[0035] What has been described above with reference to the control device also applies analogously to the motor vehicle and vice versa.

[0036] Furthermore, a method for controlling the operation of a battery-electric motor vehicle after a fall-over situation is provided. The motor vehicle has a high-voltage storage device and a high-voltage system with high-voltage components. The method comprises: disconnecting the high-voltage storage device from the high-voltage system at all poles after the fall-over situation; detecting a remaining voltage on a Y-path of the high-voltage system via a state-dependent measuring device after the high-voltage storage device has been disconnected, the measuring device having an active and an inactive state; and switching the measuring device to the active state and coupling it to the Y-path in order to actively reduce the detected voltage remaining in the Y-path.

[0037] The control method may be a computer-implemented method, ie one, several or all steps of the method may be carried out at least partially by a computer or a data processing device, optionally the control device.

[0038] What has been described above with reference to the control device and the motor vehicle also applies analogously to the method and vice versa.

[0039] Furthermore, a computer program is provided, comprising instructions which, when executed by a computer, cause the computer to at least partially execute or carry out the method described above. The program code of the computer program can be in any desired code, in particular in a code suitable for motor vehicle control systems.

[0040] What has been described above with reference to the control device, the motor vehicle and the method also applies analogously to the computer program and vice versa.

[0041] Furthermore, a computer-readable medium, in particular a computer-readable storage medium, is provided. The computer-readable medium comprises instructions which, when executed by a computer, cause the computer to at least partially execute or perform the method described above.

[0042] This means that a computer-readable medium can be provided that contains a computer program as defined above. The computer-readable medium can be any digital data storage device, such as a USB flash drive, a hard disk, a CD-ROM, an SD card, or an SSD card (or SSD drive / SSD hard disk).

[0043] The computer program does not necessarily have to be stored on such a computer-readable storage medium in order to be made available to the motor vehicle, but can also be obtained via the Internet or otherwise externally.

[0044] What has been described above with reference to the method, the control device, the computer program and the motor vehicle also applies analogously to the computer-readable medium and vice versa.

[0045] An optional embodiment is described below with reference to Figures 1 and 2.

[0046] Fig. 1 schematically shows a motor vehicle with a control device according to the disclosure for operating a battery-electric motor vehicle after an accident situation, and Fig. 2 schematically shows a flow diagram of a method according to the disclosure for controlling operation of the motor vehicle.

[0047] The motor vehicle 1, shown only schematically in Figure 1, according to an optional embodiment has the disclosed control device 2. The motor vehicle 1 further has a high-voltage storage device 4. Electrical energy for the high-voltage components of the high-voltage system can be provided via the high-voltage storage device 4. A measuring device 3 can also be provided. The measuring device can comprise an insulation monitoring device and / or an insulation monitor. The control device 2 is designed to carry out the method V, described in detail below with reference to Figure 2, for controlling the operation of a battery-electric motor vehicle 1 after a tip-over situation. In a first step S1, the method comprises an all-pole disconnection of the high-voltage storage device 4 from the high-voltage system after the tip-over situation.In a further step S2, a remaining voltage on a Y-path of the high-voltage system is detected via a state-dependent measuring device 3 after the high-voltage storage device 4 has been disconnected. The measuring device 3 has an active and an inactive state. Furthermore, in a further step S3, the measuring device 3 is switched to the active state and coupled to the Y-path in order to actively reduce the detected voltage remaining in the Y-path. For this purpose, the measuring device 3 can be transferred to the active state when the high-voltage storage device 4 is disconnected from the high-voltage system.The active state of the measuring device can be understood in such a way that a voltage measurement or insulation resistance measurement does not necessarily have to be carried out in this active state, so that a switching of one or more switchable elements of the measuring device takes place, whereby the total insulation resistance is reduced for the period of the active state.

[0048] Furthermore, it can be provided that the measuring device 3 comprises an insulation monitoring device and / or an insulation monitor. When the measuring device 3 is in an active state, the remaining voltage can be actively reduced. It is provided that reducing the voltage comprises discharging Y capacitors of the high-voltage components. Furthermore, coupling the measuring device 3 comprises coupling it to the high-voltage negative side of the Y path. The insulation monitor can also assume various positions or states depending on the current parameters and the specific system requirements. During normal operation of the insulation monitor, the high-voltage system is in a normal operating state, and the insulation monitor continuously monitors the insulation integrity to ensure that no insulation faults are present.If a potential insulation fault or a reduction in insulation resistance is detected in the high-voltage system, the insulation monitor can enter a warning state. In this state, a warning signal can be provided / output. If a serious insulation fault or a dangerous reduction in insulation integrity is detected, the insulation monitor can trigger a shutdown of the high-voltage system. In this state, the connection between the high-voltage storage system and the high-voltage components is completely interrupted to ensure safety. The RF components are then discharged, as disclosed.

[0049] Furthermore, the high-voltage system can be disconnected from the high-voltage storage device 4 via controllable switching elements, and monitoring of the switching elements can be provided via a switching element sticking detection system. The switching elements can be designed as contactors. The voltage and current from the high-voltage storage device 4 can be supplied to the high-voltage system and the high-voltage components via the contactors. A high-voltage component can comprise the drive(s). The contactors can be controlled via the control device 2. It can be provided that the switching elements have at least one switching element-bridging resistance element. The resistance element can be designed as a single resistance element or a resistance cascade. Contactor sticking detection can be provided. List of reference symbols

[0050] 1 Motor vehicle 2 Control device

[0051] 3 Measuring device

[0052] 4 high-voltage storage units

[0053] V Procedure S1-S3 Process steps

Claims

Patent claims 1. Control device (2) for operating a battery-electric motor vehicle (1) after an accident situation, wherein the control device (2) is designed to: - to disconnect a high-voltage storage device (4) of the motor vehicle (1) from a high-voltage system comprising high-voltage components after the accident situation; - after the high-voltage storage device (4) has been disconnected, a remaining voltage on a Y-section of the high-voltage system is detected via a measuring device (3) as a function of the state of the measuring device (3), wherein the measuring device (3) has an active and an inactive state, characterized in that - the control device (2) is designed to switch the measuring device (3) into the active state and to couple it to the Y-path in order to actively reduce the detected voltage remaining in the Y-path.

2. Control device (2) according to the preceding claim, characterized in that the measuring device (3) comprises an insulation monitoring device and / or an insulation monitor.

3. Control device (2) according to at least one of the preceding claims, characterized in that the reduction of the voltage comprises a discharging of Y capacitors of the high-voltage components.

4. Control device (2) according to at least one of the preceding claims, characterized in that the coupling of the measuring device (3) comprises coupling it to the high-voltage negative side of the Y-path.

5. Control device (2) according to at least one of the preceding claims, characterized in that the high-voltage system is separated from the high-voltage storage device (4) via controllable switching elements and monitoring of the switching elements is provided via a switching element sticking detection device.

6. Control device (2) according to the immediately preceding claim, characterized in that the switching elements have at least one switching element bridging resistance element.

7. Motor vehicle, characterized in that the motor vehicle comprises the control device according to one of claims 1 to 6.

8. Method (V) for controlling the operation of a battery-electric motor vehicle (1) after a fall-over situation, wherein the motor vehicle (1) has a high-voltage storage device (4) and a high-voltage system with high-voltage components, the method comprising: - All-pole separation (S1) of the high-voltage storage device (4) from the high-voltage system after the fall-over situation; - detecting (S2) a remaining voltage on a Y-section of the high-voltage system via a state-dependent measuring device (3) after disconnecting the high-voltage storage device (4), wherein the measuring device (3) has an active and an inactive state, - Switching the measuring device (3) to the active state and coupling it to the Y-path in order to actively reduce the detected voltage remaining in the Y-path.

9. A computer program, characterized in that the computer program comprises instructions which, when the program is executed by a computer, cause the computer to carry out the method according to claim 8.

10. A computer-readable medium, characterized in that the computer-readable medium comprises instructions which, when executed by a computer, cause the computer to carry out the method according to claim 8.

Images