Circuit device and method for controlling a self-discharge of a respective electrical energy storage device in at least one electrical component of a motor vehicle and corresponding motor vehicle

Abstract

Circuit device (S) for controlling a self-discharge of a respective electrical energy storage device (16) of at least one electrical component (15) of a motor vehicle (10), wherein the at least one component (15) is connected for its respective energy supply to an electrical system (11) of the motor vehicle (10) for receiving an electrical supply voltage (U) and a central control device (23) is provided for controlling the self-discharge, which is designed to signal the triggering of the respective self-discharge to the at least one electrical component (15) by means of a predetermined signaling, characterized in that the control device (23) is designed to carry out a signal transmission to the at least one component (15) via the electrical system (11) as a signal for the triggering and to modulate the supply voltage (U) in the electrical system (11) for this purpose, and the at least one component (15) is designed to start the self-discharge if the modulation of the supply voltage (U) fulfills a predetermined triggering criterion (21), wherein the triggering criterion (21) comprises that a predetermined OK signal is missing in the supply voltage (U).

Description

[0001] The invention relates to a circuit device, such as can be provided in a motor vehicle, for triggering a self-discharge or self-discharge of its local electrical energy storage device in at least one electrical component of the motor vehicle if the motor vehicle is involved in a crash (collision). The invention also encompasses a method for triggering the self-discharge in the at least one component, as well as a motor vehicle having the circuit device according to the invention.

[0002] In a hybrid vehicle or a purely electrically powered electric vehicle, a high-voltage electrical system can be provided in which a supply voltage greater than 60 volts is provided to supply energy to at least one electrical component of the motor vehicle, for example, an inverter. In such an electrical system, the electrical system voltage or supply voltage can be supported or fed by a central energy storage device, for example, an electric battery. In the case of a high-voltage electrical system, this can be a high-voltage battery. The supply voltage is usually a direct current (DC). The electrical system for distributing the supply voltage can have an electrical bus system (power bus), which can be designed, for example, based on at least one cable per electrical pole (positive pole or negative pole) and / or at least one busbar per electrical pole.As an electrical component, the inverter of a traction drive of the motor vehicle can be connected to an on-board electrical system in the manner mentioned. Furthermore, at least one electrical component can be connected, which can be responsible, for example, for electrically charging the central energy storage device of the motor vehicle and / or an electrical component for controlling the temperature of a coolant and / or for air conditioning the passenger compartment of the motor vehicle. Additionally or alternatively, a DC-DC converter for generating a low-voltage on-board electrical system, for example a 12-volt on-board electrical system, can be provided as an electrical component.

[0003] An electrical system, especially a high-voltage electrical system, should be designed to be crash-proof. In addition to mere deformation towards an obstacle and towards the passenger compartment, the discharge of the vehicle's electrical components must also be ensured. The electrical components must preferably be able to handle this discharge themselves, i.e. self-discharge or intrinsic discharge of a respective local electrical energy storage device in each electrical component must be possible. Such an energy storage device can, for example, be a local smoothing capacitor and / or buffer capacitor and / or a separate buffer battery for the respective component. This is because an electrical component can, for example, have a capacitor for supporting and / or filtering the supply voltage received from the electrical system.In particular, an inverter, such as a pulse inverter, should be mentioned as an electrical component that can control a three-phase machine for vehicle traction.

[0004] Self-discharge can be carried out in an electrical component by a discharge circuit, which can be based, for example, on one or more electrical resistance elements and one or more electrical and / or mechanical and / or electromechanical switches. The discharge circuit, or at least some parts thereof, can be located on a circuit board that can be arranged within the component. The local energy storage device, for example, a capacitor, can be located at a separate location within the electrical component.

[0005] In order to signal an electrical component that it should trigger its self-discharge, i.e., activate its discharge circuit to electrically discharge the local electrical energy storage device, for example, to discharge a capacitor, a communication connection must be provided from a central control device, which detects the presence of a crash, for example, to each electrical component to be controlled. In the event of a crash, however, there is a risk that such a communication connection will be interrupted before a trigger signal triggering the self-discharge can be successfully transmitted to at least one electrical component.

[0006] It is known from DE 10 2016 103 829 A1 and DE 10 2016 115 823 A1 that a motor vehicle's electrical system can be provided with at least one switch that can interrupt an electrical connection in the electrical system. This can prevent an uncontrolled flow of current, for example, in the event of a crash. Powerline communication via current-carrying lines of the electrical system can be provided to trigger the switching elements in the electrical system.

[0007] DE 10 2005 036 174 A1 discloses that, in the event of a crash signal, a battery to be protected is only disconnected from the vehicle's electrical system if the crash signal exceeds a minimum threshold for a predetermined minimum period. This prevents false triggering.

[0008] DE 10 2016 224 002 A1 comprises a method for discharging a battery module having at least two battery cells of a battery having at least two battery modules, wherein the battery cells of a respective one of the battery modules are arranged adjacent to one another and are mechanically and electrically connected to one another, wherein in each of the battery modules the respective battery cells are individually activated and deactivated with regard to an energy storage function by means of a cell switching unit, wherein the battery cells of the battery module to be discharged are selectively electrically coupled one after the other to a discharge device by means of the cell switching unit starting from a predetermined one of the battery cells in order to electrically discharge the battery cells one after the other to discharge the battery module.

[0009] EP 2 359 451 B1 describes a decentralized system of energy consumers and energy sources, the use of which is monitored, controlled and optimized by means of a method using a KeepAlive signal that regularly maintains communication between two communication partners.

[0010] DE 10 2016 103 829 A1 discloses a power supply unit for a vehicle, comprising an input terminal with a first conductor for carrying a first voltage, and a second conductor for carrying a second voltage. Furthermore, the power supply unit comprises a voltage converter, which is electrically coupled to the first conductor and the second conductor for transmitting electrical energy between them, and a load terminal. Furthermore, the power supply unit comprises a power distributor with at least one first fuse element and at least one second fuse element, wherein the at least one first fuse element is electrically coupled to the first conductor on the input side, and the at least one second fuse element is electrically coupled to the second conductor on the input side.The load connection comprises an interface to which the at least one first fuse element and the at least one second fuse element are electrically coupled on the output side. The respective interface is designed to be electrically coupled to a load for providing the first voltage or the second voltage, respectively. A power supply system is also specified.

[0011] The invention is based on the object of triggering a self-discharge of the local electrical energy storage device of at least one electrical component in a motor vehicle from a central control device.

[0012] The problem is solved by the subject matter of the independent patent claims.

[0013] Advantageous embodiments of the invention are described by the dependent claims, the following description and the figures.

[0014] The invention provides a circuit device for controlling the said self-discharge of a respective electrical energy storage device of at least one electrical component of a motor vehicle. The invention is based on the assumption that the at least one component is connected to an electrical system of the motor vehicle for receiving an electrical supply voltage for its respective energy supply. The at least one component therefore receives the electrical power for its own operation from the electrical system. Each of the at least one electrical component can have a discharge circuit for self-discharge of a respective energy storage device of the component, as is known per se from the prior art.To control the self-discharge, according to the circuit device, a central control device is provided in the motor vehicle, which is configured to signal the initiation of the respective self-discharge to the at least one electrical component by means of a predetermined signaling. In other words, if the self-discharge of the local energy storage device of the at least one component needs to be triggered in the motor vehicle, a central control device, for example a control unit, can trigger this in the at least one component by means of a predetermined type of signaling.

[0015] In order to make this signaling reliable, i.e. to ensure the triggering or the transmission of information for triggering the self-discharge from the central control device to the at least one component, the invention provides that the control device is designed to transmit a signal for triggering to the at least one component not via a separate communication line, but via the on-board electrical system itself, and to modulate the supply voltage in the on-board electrical system for this purpose. In other words, no additional communication line is provided. Instead, the on-board electrical system itself is used as the communication line, i.e. the positive and negative lines of the on-board electrical system. Since the supply voltage is already present in the on-board electrical system, this is modulated, i.e. changed over time, to transmit the information relating to triggering.The at least one component in which the self-discharge is to be triggered is configured to start the self-discharge if the modulation of the supply voltage meets a predetermined triggering criterion. In other words, the at least one component can monitor the supply voltage, in particular its temporal profile, and, if the supply voltage meets the triggering criterion, can start the self-discharge, i.e., for example, control the discharge circuit accordingly. Modulating the supply voltage means that the supply voltage is temporarily changed around its mean or nominal value using an AC voltage signal. This AC voltage signal can be generated by the central control device.

[0016] The invention offers the advantage that the information required to trigger self-discharge is transmitted via the vehicle's electrical system, which, due to its design, particularly the thickness of the cables, has proven particularly robust with respect to the effects of a crash. Another advantage is that no separate communication line needs to be installed in the vehicle.

[0017] According to the invention, the triggering criterion includes the absence of a predetermined OK signal in the supply voltage. In other words, the control device must transmit the OK signal continuously or at predetermined times to prevent self-discharge.

[0018] The triggering criterion ensures that self-discharge begins if at least one component no longer receives the OK signal in the supply voltage, or if it misses or fails to detect it. This offers the advantage that if a line in the vehicle electrical system is interrupted, making electrical signal transmission between the central control unit and the at least one component impossible, this very interruption leads to or triggers self-discharge.

[0019] The invention also includes embodiments which provide additional advantages.

[0020] In one embodiment, said triggering criterion comprises a predetermined trigger signal being modulated onto the supply voltage. In other words, to trigger or start the self-discharge, the control device must modulate an explicit or explicit trigger signal onto the supply voltage. This prevents false triggering, such as could be caused by an interference signal in the vehicle's electrical system. The trigger signal can be coded for this purpose, as this cannot occur accidentally in the event of an interference signal.

[0021] The provision of the trigger signal and the absence of the OK signal can also be combined, thus providing robust protection against false triggering.

[0022] In one embodiment, the triggering criterion includes the absence of said OK signal for a predetermined minimum period of time. For example, the minimum period of time can be in a range from 10 milliseconds to 2 seconds. This provides the advantage that a single absence of an OK signal for a period of time shorter than the minimum period does not trigger the self-discharge. For example, this can compensate for the influence of a temporary disturbance in the supply voltage.

[0023] In one embodiment, said central control device is configured to modulate the supply voltage using a mean-free AC voltage signal. In other words, the mean voltage value of the supply voltage is not changed by the modulation or remains unchanged. This provides the advantage of avoiding a potential change in the vehicle electrical system, which could be caused by the modulation.

[0024] In one embodiment, the described discharge circuit is provided in the at least one electrical component for the said self-discharge of the local energy storage device, which is configured to connect electrical poles of the energy storage device via at least one discharge resistor. In other words, there is at least one electrical component, namely the at least one discharge resistor, through which an electrical current only flows if the discharge circuit is triggered, i.e., if the self-discharge is to be carried out. Thus, advantageously, there is no need to wait for the energy storage device of the component to discharge itself solely through continued operation of the component. Preferably, the electrical resistance value of the at least one discharge resistor is overall smaller than an electrical resistance of the electrical component as it results during normal operation of the electrical component.As a result, the discharge time of the energy storage device is shorter than if the energy storage device were discharged solely by continuing to operate the electrical component.

[0025] In one embodiment, the central control device is configured to trigger the respective self-discharge in the at least one electrical component if a crash signal is received from a collision sensor device. For example, the crash signal can be received from an airbag control unit of the motor vehicle. Coupling the collision sensor device with the control device offers the advantage that the time delay between detection of a crash and triggering of the self-discharge is short, i.e., the self-discharge occurs when the onset of the crash is sensed, before, for example, an electrical line in the vehicle electrical system is destroyed or interrupted during the crash, thus making communication impossible.

[0026] In one embodiment, a predetermined communication protocol for bus communication is provided for said supply voltage modulation. This provides the advantage that at least one component can be addressed individually or specifically via the vehicle electrical system. In other words, addressed or receiver-specific communication is preferably provided.

[0027] The invention also encompasses a motor vehicle configured according to the invention. In other words, the motor vehicle according to the invention has an electrical system for distributing a supply voltage and at least one electrical component connected to the electrical system, which has its own energy storage device, for example, a capacitor, for smoothing and / or filtering the received supply voltage. Overall, an embodiment of the circuit device according to the invention is provided in the motor vehicle according to the invention.

[0028] The motor vehicle according to the invention is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus or motorcycle.

[0029] The operation of the circuit device according to the invention results in a method which is also a component of the invention. The method according to the invention serves to trigger a self-discharge of a respective energy storage device in at least one electrical component in a motor vehicle. The method assumes that the at least one component receives an electrical supply voltage from an electrical system of the motor vehicle for its power supply. In other words, the supply voltage is the operating voltage or on-board network voltage of the electrical system. It can, in particular, be a high-voltage voltage (high-voltage - electrical voltage greater than 60 volts).The method according to the invention provides that in the at least one component, the self-discharge of its local or own energy storage device is triggered by a central control device via the on-board electrical system by means of a modulation of the supply voltage if the modulation of the supply voltage fulfills a predetermined triggering criterion, wherein the triggering criterion comprises the absence of a predetermined OK signal in the supply voltage (U). In the manner described, this results in the advantage that no additional or separate communication line has to be laid between the central control device and the at least one component. The control device is therefore an element of the motor vehicle which is different from the at least one component and is connected to the at least one component via the on-board electrical system.

[0030] The invention also includes embodiments of the method according to the invention that have features already described in connection with the embodiments of the control device according to the invention. For this reason, the corresponding embodiments of the method according to the invention are not described again here.

[0031] The invention also includes combinations of the features of the described embodiments.

[0032] Exemplary embodiments of the invention are described below. Shown are: Fig. 1 a schematic representation of an embodiment of the motor vehicle according to the invention with an embodiment of the supply device according to the invention; and Fig. 2 a schematic representation of an energy storage device with a discharge circuit, as used in an electrical component of the motor vehicle of Fig. 1 can be provided.

[0033] The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention that can be considered independently of one another, each of which also develops the invention independently of one another. Therefore, the disclosure is intended to encompass combinations of the features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0034] In the figures, the same reference symbols designate elements with the same function.

[0035] Fig. 1 shows a motor vehicle 10, which may be a motor vehicle, in particular a passenger car or truck, or a passenger bus or a motorcycle. An electrical on-board network 11 may be provided in the motor vehicle 10, via which an electrical supply voltage U, in particular a direct voltage, can be generated from an electrical voltage source 12. The voltage source 12 may, for example, comprise an electrical battery and / or a generator. The on-board network 11 may, in particular, be a high-voltage on-board network in which the supply voltage U is greater than 60 volts. The on-board network 11 may have an electrical positive line 13 and an electrical negative line 14, each of which may, for example, be provided or constructed on the basis of at least one cable and / or at least one busbar.The electrical supply voltage U can be generated or provided by the voltage source 12 between the positive line 13 and the negative line 14.

[0036] At least one electrical component 15 can be connected to the vehicle electrical system 11. Examples of such an electrical component 15 are: a pulse-controlled inverter for operating an electrical machine and / or an air conditioning system for the motor vehicle 10. The at least one electrical component 15 can receive the supply voltage U from the vehicle electrical system 11 for its operation in order to thereby obtain the electrical power for operation. Each electrical component 15 can have its own local energy storage device 16, which can be formed, for example, on the basis of an electrical capacitor.

[0037] In the event of a crash of the motor vehicle 10, it is of interest to consume or dissipate the electrical energy stored locally in the energy storage device 16.

[0038] For this purpose, a circuit device S can be implemented in the motor vehicle 10 to ensure rapid discharge of electrical energy in the event of a crash. For this purpose, a discharge circuit 17 can be provided in each component 15. By way of example, it is shown how a discharge circuit 17 can have at least one switching element 18 and at least one electrical discharge resistor 19, which can be connected between electrical poles of the energy storage device 16. A switching logic 20 of the discharge circuit 17 can, in the event that a triggering criterion 21 is met, switch the switching element 18 electrically conductive and thereby conduct a discharge current 22 from the energy storage device 16 of the component 15 through the electrical discharge resistor 19, whereby the energy stored in the energy storage device 16 is dissipated or discharged.

[0039] To trigger or start this self-discharge by means of the discharge circuit 17, a central control device 23 can be provided in the motor vehicle 10, wherein the control device 23 can be implemented, for example, on the basis of a control unit. The control device 23 can receive a crash signal 24 to trigger the respective self-discharge in the at least one component 15 and then trigger or command the discharge of the energy storage devices 16 in the at least one component 15. This occurs in the motor vehicle 10 via the on-board electrical system 11 itself, i.e., in particular, via the positive line 13 and the negative line 14. For this purpose, it can be provided that an electrical, mean-free AC voltage signal 25 is modulated onto the supply voltage U as a trigger signal. An exemplary curve of the AC voltage signal 25 is shown in Fig. 1 over time t is symbolically represented in a waveform diagram. The control device 23 can be electrically connected to the positive line 13 and the negative line 14 via a respective decoupling capacitor 26 to modulate the AC voltage signal 25. This prevents the supply voltage U from acting on the control device 23 as a DC voltage. A PLC control element 27 (PLC - Power Line Communication) can be provided for imprinting. A communication protocol for bus communication can be provided for transmitting a trigger command.

[0040] In addition or as an alternative to the trigger signal, it can also be provided in the crash-free case to modulate an OK signal onto the supply voltage U by means of the alternating voltage signal 25.

[0041] The switching logic 20 in the respective component 15 can, for example, provide as trigger criterion 21 that the trigger signal must be recognizable or detected in the supply voltage U. Additionally or alternatively, the absence of the OK signal can be provided as trigger criterion 21.

[0042] If the discharge circuit 17 in a component 15 is triggered via the on-board network 11 by modulating the supply voltage U, then, for example, the at least one switching element 18 is switched electrically conductive in the manner described and the discharge current 22 is thereby conducted through the at least one discharge element or the at least one discharge resistor 19.

[0043] Fig. Figure 2 illustrates, by way of example, a construction of an energy storage device 16, as may be provided in a component 15. It shows how the energy storage device 16 may comprise foils as capacitor windings 28. For the sake of clarity, only three capacitor windings 28 are provided with a reference symbol. Fig. 2 shows, in a section 29, a transverse view of a layered structure of the capacitor windings 28, wherein an insulating film 32 can be provided between electrically conductive films 30 of one polarity and an electrically conductive film 31 of the other polarity. The films can, for example, each be wound into a roll in the capacitor windings 28. Surrounding metallic teeth 33 can cut into the capacitor windings 28 upon deformation of a housing 34 of the energy storage device 16 and electrically bridge several layers of the alternating positive and negative films, thereby creating a short circuit.

[0044] The discharge circuit 17 can be embedded in the energy storage device 16. To check the supply voltage U, a connecting line 34 for the discharge circuit 17 can be routed or laid out of the housing 34.

[0045] Overall, the examples show how the invention can provide a crash-safe, highly dynamic rapid discharge of high-voltage components in an electric, hybrid or fuel cell vehicle.

Claims

[1] Circuit device (S) for controlling a self-discharge of a respective electrical energy storage device (16) of at least one electrical component (15) of a motor vehicle (10), wherein the at least one component (15) is connected for its respective energy supply to an electrical system (11) of the motor vehicle (10) for receiving an electrical supply voltage (U) and a central control device (23) is provided for controlling the self-discharge, which is designed to signal the triggering of the respective self-discharge to the at least one electrical component (15) by means of a predetermined signaling, characterized by , that the control device (23) is designed to carry out a signal transmission to the at least one component (15) via the electrical system (11) as a signal for the triggering and to modulate the supply voltage (U) in the electrical system (11) for this purpose, and the at least one component (15) is designed to start the self-discharge if the modulation of the supply voltage (U) fulfills a predetermined triggering criterion (21), wherein the triggering criterion (21) comprises that a predetermined OK signal is missing in the supply voltage (U). [2] Circuit device (S) according to claim 1, wherein the triggering criterion comprises that a predetermined triggering signal is modulated onto the supply voltage (U). [3] Circuit device (S) according to one of the preceding claims, wherein the triggering criterion (21) comprises that the OK signal is absent for a predetermined minimum period of time. [4] Circuit device (S) according to one of the preceding claims, wherein the control device (23) is designed to carry out the modulation of the supply voltage (U) by means of a mean-value-free alternating voltage signal (25). [5] Circuit device (S) according to one of the preceding claims, wherein a discharge circuit (17) is provided in the at least one electrical component (15) for the self-discharge, which is designed to connect electrical poles of the energy store (16) via at least one discharge resistor (19). [6] Circuit device (S) according to one of the preceding claims, wherein the control device (23) is designed to trigger the respective self-discharge if a crash signal (24) is received from a collision sensor device. [7] Circuit device (S) according to one of the preceding claims, wherein a predetermined communication protocol for bus communication is provided for the modulation. [8] Motor vehicle (10) with an electrical system (11) for distributing a supply voltage (U) and with at least one electrical component (15) connected to the electrical system (11) and having its own energy storage device (16), characterized by that a switching device (S) according to one of the preceding claims is provided in the motor vehicle (10). [9] Method for operating a circuit device (S) for triggering a self-discharge of a respective energy storage device (16) in at least one electrical component (15) of a motor vehicle (10) according to one of claims 1 to 7, wherein the at least one component (15) receives an electrical supply voltage (U) from an electrical system (11) of the motor vehicle (10) for its energy supply, characterized by in that in the at least one component (15), the self-discharge of its energy storage device (16) is triggered by a central control device (23) via the electrical on-board network (11) by means of a modulation of the supply voltage (U) if the modulation of the supply voltage (U) fulfills a predetermined triggering criterion, wherein the triggering criterion (21) comprises that a predetermined OK signal is missing in the supply voltage (U).

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