Control device for high-voltage battery and method for operating control device

Abstract

A control device (1) for a high-voltage battery (2) in a motor vehicle (3) includes at least a high-voltage battery (2) and a control device (4) for the high-voltage battery (2); wherein the high-voltage battery (2) is connected to an intermediate electrical circuit (6) of the motor vehicle (3) via a switchable first electrical connection (5) and to the control device (4) via a switchable second electrical connection (7); wherein the control device (1) has a switching device (8) by which the first connection (5) and the second connection (7) can be switched, such that in a first state of the switching device (1), the high-voltage battery (2) is connected to the intermediate circuit (6) and the control device (4) is connected to the high-voltage battery (2); wherein in a second state, the high-voltage battery (2) is disconnected from the intermediate circuit (6) and the control device (4) is connected to the high-voltage battery (2); and in a third state, the control device (4) is disconnected from the high-voltage battery (2) and connected to the intermediate circuit (6).

Description

Technical Field

[0001] This invention relates to a control device for a high-voltage battery and a method for operating the control device. The control device and the high-voltage battery are particularly intended for use in motor vehicles and are preferably disposed therein. Background Technology

[0002] High-voltage batteries in motor vehicles, such as those with a 48-volt power supply, typically have a control device (Battery Management System - BMS). This control device draws its voltage from the 48-volt power supply; that is, the BMS is powered by the battery cells themselves. The BMS has very low quiescent current consumption, so even long standby periods are usually not a problem. However, if the defined duration is exceeded or the 48-volt system malfunctions, the high-voltage battery will discharge.

[0003] If the high-voltage battery voltage drops below the defined limit, the battery cell will suffer irreversible damage and the high-voltage battery will malfunction. If the voltage drops further, the BMS will no longer be able to supply power. In this situation, communication with the vehicle is impossible via external service equipment (such as diagnostic testers) or via CAN (Controller Area Network, bus system).

[0004] This leads to several problems. On the one hand, the high-voltage battery is irreversibly damaged, resulting in high repair costs. On the other hand, internal faults in the high-voltage battery cannot be diagnosed, and these faults can also cause discharge. Deep discharge of the high-voltage battery and control equipment failure (such as controller or CAN transceiver failure) cannot be distinguished. Since lithium-ion batteries are treated as hazardous materials, specific regulations apply to the handling of these components. Furthermore, energy storage devices (batteries) are classified for transport and storage according to VDA regulations. A prerequisite for this is determining the condition of the energy storage device, for which communication is necessary. If classification cannot be achieved, the energy storage device must be treated as faulty (critical) and special procedures must be initiated (it can no longer be transported in standard packaging, stored in isolated containers, etc.). This can sometimes incur additional costs.

[0005] High-voltage batteries are known to be designed with insulation between the battery voltage and the voltage supply to the battery management system (BMS). This is necessary for safety reasons (due to the high voltage level of the high-voltage battery). This technology is particularly used for all known 48-volt batteries. The BMS is therefore powered by a 12-volt voltage source within the vehicle. The problem described at the beginning does not exist here.

[0006] The cost of isolating different supply voltages increases the direct cost of the high-voltage battery. Furthermore, energy supply security is lower because the high-voltage contactors and BMS are typically powered by 12 volts instead of the 48 volts supplied by the high-voltage battery.

[0007] The control device for high-voltage batteries and the method for operating the control device are known from document DE 10 2020 110 174 A1.

[0008] Document US 2020 / 0353842 A1 discloses a method for controlling batteries in motor vehicles. Summary of the Invention

[0009] Therefore, the technical problem to be solved by the present invention is to at least partially solve the problems described in the prior art. In particular, a control device for a high-voltage battery is proposed, which, on the one hand, ensures high safety in the energy supply to the control equipment used in the control device, and on the other hand, reliably determines the state of the high-voltage battery.

[0010] The features described in each claim may be combined with each other in a technically suitable manner and may be supplemented by details from the description and / or drawings, which indicate further variations of the invention.

[0011] A control device for a high-voltage battery in a motor vehicle is proposed. The high-voltage battery is particularly designed for use in a motor vehicle. The control device includes at least one high-voltage battery and a control device (or controller) for the high-voltage battery. The high-voltage battery is connected to an electrical intermediate circuit of the motor vehicle via a switchable first electrical connection and to the control device via a switchable second electrical connection. The control device has a switching mechanism that can switch the first and second connections, such that in a first state of the switching mechanism, the high-voltage battery is connected to the intermediate circuit and the control device is connected to the high-voltage battery. In a second state, the high-voltage battery is disconnected from the intermediate circuit (while the control device remains connected to the high-voltage battery), and in a third state, the control device is disconnected from the high-voltage battery and connected to the intermediate circuit. The control device is connected to the intermediate circuit via a first diode, such that current can only flow from the intermediate circuit to the control device.

[0012] Diodes, especially electronic structural components, allow current to flow in one direction and block current in another. Therefore, a flow direction and a cutoff direction are involved. The flow direction here extends from the intermediate circuit towards the control device.

[0013] The high-voltage battery is designed to provide a first supply voltage of at least 30 volts, particularly at least 40 volts, and preferably at least 45 volts. In particular, the first supply voltage is 48 volts.

[0014] If the high-voltage battery can provide sufficient energy to operate the control equipment, the control equipment is connected to the high-voltage battery in the control unit to provide the supply voltage (or power supply voltage). This specifically means that no additional battery is specified in the motor vehicle through which the control equipment is powered by the supply voltage.

[0015] High-voltage batteries are particularly connected to an electrical grounding device. The grounding device is a conductor that is typically equipped with zero potential, which in particular represents the reference potential for all signals and operating / supply voltages of the control devices.

[0016] On the other hand, the high-voltage battery can be connected to an intermediate circuit or an electrical appliance in the vehicle via the first connection, or, if the control device is located in the vehicle, to the vehicle itself. The electrical appliances in the vehicle are thus electrically connected to the high-voltage battery via the first connection.

[0017] The control device is connected to a grounding device on one hand. On the other hand, the control device is connected to a high-voltage battery via a second connection. The first connection can be disconnected by the control device or re-established if necessary. For this purpose, a first switch, such as a bistable relay or a MOSFET switch, is provided, which can be controlled by the control device.

[0018] A bistable relay can have two different stable switching states in the absence of current.

[0019] In particular, the first switch can maintain the first connection disconnected even when there is no supply voltage. That is, if the high-voltage battery cannot provide sufficient supply voltage, the first switch will disconnect the high-voltage battery from the intermediate circuit.

[0020] In particular, the first connection can be disconnected or re-established by the control device alone. The first switch, therefore, is operated solely by the control device.

[0021] The control device or switching device may be designed such that it allows exactly three of the aforementioned states.

[0022] Specifically, the control device is connected to the high-voltage battery via a first voltage converter. The second supply voltage generated by the first voltage converter is lower than the first supply voltage provided by the high-voltage battery to the first voltage converter and intermediate circuit. In the third state, the control device is connected to the intermediate circuit via the first voltage converter and a first diode.

[0023] Specifically, in the first state of the switching device, the high-voltage battery is connected to the intermediate circuit, and the control device is connected to the high-voltage battery. In the second state, the high-voltage battery is disconnected from the intermediate circuit, and the control device is connected to the high-voltage battery. In the third state, the high-voltage battery is disconnected from both the intermediate circuit and the control device, and the control device is connected to the intermediate circuit.

[0024] The first voltage converter is particularly positioned between the high-voltage battery and the control equipment, especially between the first switch and the control equipment.

[0025] Specifically, the second supply voltage is at most 50% of the first supply voltage. Specifically, the second supply voltage is at most 20 volts, preferably at most 15 volts. Specifically, the second supply voltage is 12 volts.

[0026] Preferably, the second supply voltage is at most 10 volts, and more preferably at most or exactly 5 volts or 3.3 volts.

[0027] In particular, the switching device has a first switch for establishing a first connection, wherein the intermediate circuit can be switched to be connected to the high-voltage battery via the first switch.

[0028] In particular, the switching device has a second switch for establishing a second connection, and the control device can be switched to connect to the high-voltage battery via the second switch.

[0029] In particular, the second switch can establish or disconnect a second conductive connection, namely the connection between the control device and the high-voltage battery.

[0030] In particular, the second switch can only be switched by the control device.

[0031] In particular, the high-voltage battery is connected to the second switch via a second diode so that current can only flow from the high-voltage battery to the second switch.

[0032] In particular, the second switch and the first diode are arranged such that only the control device is connected to the high-voltage battery when the second connection is established.

[0033] The first diode is arranged in such a way that when the second connection between the control device and the high-voltage battery is established, no (or virtually no) current can flow through the first diode to the intermediate circuit.

[0034] In particular, the electrical connection is designed so that current can flow from the high-voltage battery to the intermediate circuit in the absence of the first diode and in the case of establishing the second connection (but this is blocked by the first diode).

[0035] In particular, with the second switch and the second diode arranged in such a way that when the second connection between the control device and the high-voltage battery is established, no (or virtually no) current can flow through the second diode to the high-voltage battery, and in particular, there is no current supplied by the intermediate circuit.

[0036] In particular, the electrical connection is designed so that, in the absence of a second diode and in the case of establishing a second connection, current can flow from the intermediate circuit and / or from the control device to the high-voltage battery (but this is blocked by the second diode).

[0037] In particular, the first connection and / or the second connection are formed by MOSFET switches.

[0038] In particular, a MOSFET switch has a gate terminal, a source terminal, and a drain terminal. If the first switch is designed as a MOSFET switch, the control device forms the gate terminal, and the high-voltage battery and intermediate circuitry form one of the source and drain terminals, respectively. If the second switch is designed as a MOSFET switch, the control device forms the gate terminal, and the high-voltage battery and control device form one of the source and drain terminals, respectively.

[0039] In particular, the second switch is a bistable relay, which can have two different stable switching states in the absence of current. Furthermore, the second switch can disconnect the second connection even when there is no supply voltage (due to a high-voltage battery, intermediate circuit, or control device).

[0040] In particular, the second connection can be switched and / or established solely by the control device. Therefore, the second switch is operated solely by the control device.

[0041] The control equipment particularly includes a system base chip. Communication between the control device and the vehicle is primarily via the system base chip, for example, through CAN. This system base chip particularly features an LDO (Low Dropout) controller. The LDO controller can regulate the output voltage, especially if the output voltage is very similar to the input voltage. Through the LDO regulator, the microcontroller of the control device can operate with a fourth supply voltage via a third connection.

[0042] Control devices include, in particular, microcontrollers. Microcontrollers are particularly capable of operating on a fourth supply voltage. This fourth supply voltage is, in particular, up to 50% of the second supply voltage, for example, 3.3 volts or 5 volts.

[0043] Microcontrollers are core components of control devices, particularly controlling all processes within those devices. Specifically, microcontrollers connect to an analog front-end via communication channels. This analog front-end detects, in particular, the cell voltages, battery pack voltages, and battery pack currents of high-voltage batteries.

[0044] Analog front-ends are circuits used to convert and process analog signals into digital signals. Analog front-ends are particularly used to detect analog signals from high-voltage batteries and transmit them as digital signals to a microcontroller.

[0045] The switching device can be manipulated, in particular, by a microcontroller. In particular, the first connection and the second connection can be restored, especially independently of each other, by the operation of the first switch and / or the second switch, or the first switch for switching the first connection and / or the second switch for switching the second connection can be controlled or manipulated.

[0046] The current state of charge of a high-voltage battery can be continuously determined during operation, especially by control devices or microcontrollers. This determination or detection can be performed using known methods, such as static voltage measurement and current integration, and / or through complex cell models.

[0047] In particular, control devices or microcontrollers can detect when the state of charge is below and / or above its limits.

[0048] Especially when the battery leaves the specified state of charge range (SOC operating range) for normal operation of the high-voltage battery, a warning can be transmitted to the vehicle via control equipment, for example, through CAN. Alternatively or additionally, erroneous inputs can be made, for example, in the control equipment, particularly in its non-volatile memory.

[0049] The control device ensures that the control equipment is connected to the high-voltage battery when sufficient energy is supplied from the high-voltage battery. Here, when the charge level falls below a first limit value of the high-voltage battery, the high-voltage battery can be disconnected from the intermediate circuit via the control device, specifically by disconnecting the first connection.

[0050] Furthermore, the control device can ensure that it can be disconnected from the high-voltage battery when the charge level falls below a second limit, particularly by disconnecting the second connection. Here, the control device remains connected to the intermediate circuit, allowing it to operate with sufficient supply voltage, for example, via a starter generator, particularly a belt-driven starter generator, arranged in the intermediate circuit.

[0051] For example, the connection between the control device and the intermediate circuit that is required in the literature DE 10 2020 110 174 A1 (thereby via the first switch) is particularly unnecessary here, because there can only be current in one direction through the first diode.

[0052] Furthermore, a method for operating a control device for a high-voltage battery is proposed. This high-voltage battery is particularly specified for use in motor vehicles. The method is specifically implemented when the high-voltage battery is arranged in a motor vehicle.

[0053] As described above, the control device includes at least one high-voltage battery and a control device for the high-voltage battery. The high-voltage battery is connected to the electrical intermediate circuit of the motor vehicle via a switchable first electrical connection and to the control device via a switchable second electrical connection. The control device has a switching device that can switch the first and second connections, such that in a first state of the switching device, the high-voltage battery is connected to the intermediate circuit and the control device is connected to the high-voltage battery. In a second state, the high-voltage battery is disconnected from the intermediate circuit (while remaining connected to the control device), and in a third state, the control device is also disconnected from the high-voltage battery and is connected to the intermediate circuit (only).

[0054] Starting from the first state of the switching device, the method includes at least the following steps:

[0055] a) Determine the current charging state of the high-voltage battery through control equipment;

[0056] If the current charging status is below the limit value

[0057] b) Establish the third state.

[0058] The above-described non-closed division of method steps into a) and b) is primarily for differentiation only and is not a mandatory sequence or association. The frequency of method steps may vary, for example, during the setup and / or operation of the system. It is also possible that the method steps overlap at least partially in time. It is particularly preferred that method step a) be performed consecutively. In particular, steps a) and b) are performed in the order shown.

[0059] Specifically, perform the following steps before step b):

[0060] i. Perform step a) and

[0061] If the current charging state is below the first limit value

[0062] ii. Establish the second state, and

[0063] iii. Perform step a) and

[0064] If the current charging state is below the second limit value

[0065] iv. Perform step b).

[0066] The first connection can be disconnected or re-established, in particular, by a control device. For this purpose, a first switch, such as a bistable relay or MOSFET, is provided, which can be controlled by the control device.

[0067] In particular, the first switch can maintain the first connection disconnected even when there is no supply voltage. That is, if the high-voltage battery cannot provide sufficient supply voltage, the first switch will disconnect the high-voltage battery from the intermediate circuit.

[0068] In particular, the first connection can be disconnected or re-established by the control device alone. The first switch, therefore, is operated solely by the control device.

[0069] In particular, the switching device has a second switch, through which the control equipment can be (only) connected to or disconnected from the high-voltage battery.

[0070] The first switch can disconnect the intermediate circuit from the high-voltage battery, but cannot disconnect the high-voltage battery from the control equipment.

[0071] In particular, step a) is executed continuously at least until step b). In particular, steps i through iv are executed in the order shown.

[0072] In particular, the second limit value is smaller than the first limit value. This method is especially effective during the period when the state of charge of the high-voltage battery decreases.

[0073] This method is especially important for protecting high-voltage batteries.

[0074] Specifically, according to step ii, disconnecting the first connection. This allows the first connection between the high-voltage battery and the intermediate circuit, particularly the electrical appliances located in the vehicle, to be interrupted so that the high-voltage battery does not continue to discharge through the vehicle.

[0075] The first limit value is particularly between 10% and 20% of the rated charge capacity of the high-voltage battery, preferably 15%. The typical operating range of high-voltage batteries used in motor vehicles particularly includes 30% to 100% of the rated charge capacity.

[0076] The second limit value is particularly less than 12% of the rated state of charge, preferably 10%.

[0077] After step ii., the high-voltage battery is connected to the control device only (via the second connection). The control device has significantly lower energy requirements than the vehicle. The vehicle continues to be connected to the control device, or may continue to communicate with the control device, for example, via CAN.

[0078] If the value falls below the second limit, the second connection is also disconnected, meaning the control device is also disconnected from the high-voltage battery. Therefore, after step b), no electrical appliances are connected to the high-voltage battery.

[0079] Specifically, prior to step b), a status signal is set in the non-volatile memory of the control device. The status of the high-voltage battery is stored in the control device via this status signal so that it can be read from the control device, for example, via a service plug or a service device external to the vehicle. Alternatively or additionally, the status signal can be transmitted to the central control unit via CAN. By storing or transmitting the status signal, fault diagnosis of the high-voltage battery can be performed even after the high-voltage battery has been completely discharged and / or damaged.

[0080] After step b), the control device no longer supplies voltage through the high-voltage battery, so that the high-voltage battery is no longer discharged by the internal electronics of the control device. The high-voltage battery, in particular, can only self-discharge, with the self-discharge rate varying monthly, for example, within a maximum range of 2% of its rated charge.

[0081] This control device specifically ensures that when the charge level falls below the second limit of the high-voltage battery, the control device disconnects from the high-voltage battery and remains connected to the intermediate circuit. The connection between the control device and the intermediate circuit must not be altered by switching (i.e., disconnecting or connecting).

[0082] In particular, the control equipment can be operated, for example, by a starter generator arranged in the intermediate circuit with sufficient supply voltage.

[0083] Especially after performing step b), after the vehicle is test-run, a third supply voltage is applied to the intermediate circuit through the vehicle.

[0084] The test run of a motor vehicle includes, for example, starting the ignition system. Specifically, during this process, the central control unit is activated and it can be determined that the high-voltage battery is no longer communicating with the central control unit, for example, via CAN.

[0085] Specifically, the central control unit initializes the pre-charge of the intermediate circuit to a determined voltage value via a second voltage converter arranged in the intermediate circuit. A third supply voltage can be applied to the control device through the connection to the intermediate circuit. This third supply voltage is applied to a first voltage converter, which then applies a second supply voltage to the control device. The third supply voltage is identical to the first supply voltage in terms of voltage value.

[0086] A supply voltage from the intermediate circuit is applied to the control device, enabling communication between the control device and the central control unit to be restored. Information from the high-voltage battery can then be transmitted to the central control unit.

[0087] By testing a motor vehicle, for example, starting a generator, especially a belt-driven generator, it can be used to generate a third supply voltage.

[0088] By restoring communication between the control device and the central control unit, the second voltage converter can be configured to regulate the third supply voltage, thereby adjusting the third supply voltage in the intermediate circuit to match the first supply voltage of the high-voltage battery. After the third supply voltage and the first supply voltage are balanced, the first connection can be reconnected, linking the high-voltage battery to the intermediate circuit.

[0089] Specifically, the switching device is operated by the control equipment and the high-voltage battery is connected to the intermediate circuit through the first connection.

[0090] Control commands used to manipulate switching devices are therefore triggered, especially by control equipment or microcontrollers.

[0091] Especially before the high-voltage battery is connected to the intermediate circuit, the third supply voltage existing in the intermediate circuit is adjusted to the first supply voltage of the high-voltage battery.

[0092] Especially after the first connection is established, the high-voltage battery is charged through the intermediate circuit.

[0093] The current state of charge can be determined, for example, based on the last stored state signal and taking into account the self-discharge of the high-voltage battery, through the control device. If the control device determines that the state of charge is below the third limit value, the establishment of the first connection is prevented.

[0094] A value below the third limit indicates at least partial damage to the high-voltage battery, which may be irreversible, thus preventing the establishment of the first connection. In particular, status signals already stored in the control equipment enable the diagnosis of high-voltage battery faults.

[0095] The third limit value is particularly maximum at 0.5% of the rated charge state, preferably 0%.

[0096] Especially after step b), the control device reconnects to the high-voltage battery via the second connection only when the high-voltage battery reaches a state of charge exceeding the fourth limit. This second connection, the connection between the high-voltage battery and the control device (i.e., the first state), is only re-established when the high-voltage battery reaches a sufficient state of charge to ensure a first supply voltage is supplied to the control device. The second connection is specifically re-established by the control device.

[0097] The fourth limit value is located between the third and second limit values ​​or between the second and first limit values.

[0098] This method or control device can protect the high-voltage battery from deep discharge because the high-voltage battery can be disconnected from all electrical appliances, including the high-voltage battery's control equipment, via a switching device. Furthermore, the high-voltage battery and control equipment can be automatically reactivated after this disconnection. Reactivation is performed via an intermediate circuit or a trial run of the vehicle. Here, the control equipment is first reactivated, and the state of charge of the high-voltage battery is inquired or determined. The high-voltage battery is then connected to the intermediate circuit and charged if necessary. If the high-voltage battery reaches a sufficient state of charge, the control equipment can be reconnected to the high-voltage battery, allowing the control equipment to apply a first supply voltage, specifically from the high-voltage battery.

[0099] Using at least one diode eliminates the need for switch contacts. This allows the control device to be designed to be more reliable and less susceptible to failure.

[0100] In particular, the control equipment of the control device, especially the central control unit, is equipped, configured, or programmed to perform the method.

[0101] Furthermore, the method can also be executed by a processor of a computer or control device.

[0102] Therefore, a system for data processing is also proposed, which includes a processor suitable for / configured to perform the method or parts of the proposed method.

[0103] A computer-readable storage medium may be configured to include instructions that, when executed by a computer / processor, enable the computer / processor to perform at least some steps of the method or the proposed method.

[0104] The description of the method can be transferred in particular to the method implemented by the control device or computer (i.e., computer or processor, data processing system, computer-readable storage medium), and vice versa.

[0105] In particular, the high-voltage battery can also operate autonomously (i.e., without a motor vehicle or not installed in a motor vehicle), wherein the high-voltage battery or the proposed control device does not have an additional voltage supply or voltage source and / or the supply voltage of the high-voltage battery is insulated from the supply voltage of the control device.

[0106] The use of the indefinite article "a" is not understood as a quantifier, especially in the claims and the description interpreting the claims. Accordingly, the relevant terms and components are understood to exist at least once, but in particular, they may exist multiple times.

[0107] It should be noted that the ordinal numbers used herein (“first,” “second,” etc.) are primarily (only) used to distinguish multiple objects, quantities, or processes of the same kind; that is, they do not, in particular, mandate the relationship and / or order between these objects, quantities, or processes. If a relationship and / or order is required, it will be explicitly stated herein or will be obvious to those skilled in the art when studying the specifically described design. As long as a component can appear multiple times (at least one), the description of one such component also applies to all or most of that component, but this is not necessarily the case. Attached Figure Description

[0108] The invention and its technical field are further described below with reference to the accompanying drawings. It should be noted that the invention is not limited to the embodiments described. In particular, unless otherwise explicitly stated, certain aspects can be extracted from the facts illustrated in the figures and combined with other components and knowledge derived from this description. It should be particularly noted that the drawings and the dimensional relationships shown are merely schematic. Wherein:

[0109] Figure 1 Motor vehicles

[0110] Figure 2 : Control devices for motor vehicles. Detailed Implementation

[0111] Figure 1 Motor vehicle 3 is shown. Figure 2 The control device 1 of the motor vehicle 3 is shown. Figure 1 and Figure 2 They will be explained together below.

[0112] The motor vehicle 3 includes a high-voltage battery 2 with a control device 1, a belt-driven starter generator 22, a second voltage converter 21, a 12-volt subnetwork 24, and a central control unit 23. The high-voltage battery 2 and the control device 1 are connected to the second voltage converter 21 and the belt-driven starter generator 22 via an intermediate circuit 6. The high-voltage battery 2 can be charged by the belt-driven starter generator 22 via the intermediate circuit 6. The high-voltage battery 2 cannot be connected to the 12-volt subnetwork 24.

[0113] Control device 1 includes a high-voltage battery 2 and a control device 4 for the high-voltage battery 2. The high-voltage battery 2 is connected to an electrical intermediate circuit 6 of the vehicle 3 via a switchable first electrical connection 5 and to the control device 4 via a switchable second electrical connection 7. Control device 1 has a switching device 8 that can switch the first connection 5 and the second connection 7, such that in a first state of switching device 8, the high-voltage battery 2 is connected to the intermediate circuit 6 and the control device 4 is connected to the high-voltage battery 2. In a second state (the only difference from the first state), the high-voltage battery 2 is disconnected from the intermediate circuit 6, and in a third state (the only difference from the second state), the control device 4 is disconnected from the high-voltage battery 2. Control device 4 is connected to the intermediate circuit 6 in all states. Control device 4 is connected to the intermediate circuit 6 via a first diode 9. Diode 9 ensures that current can only flow from the intermediate circuit 6 to the control device 4.

[0114] If the high-voltage battery 2 can provide sufficient energy to operate the control device 4, then the control device 4 is connected to the high-voltage battery 2 in the control unit 1 to provide a first supply voltage 13. That is to say, no other battery is specified in the motor vehicle 3 through which the control device 4 is powered by the supply voltage.

[0115] The high-voltage battery 2 is connected to the grounding device 26 on one side. On the other side, the high-voltage battery 2 can be connected to the intermediate circuit 6 or to the electrical appliances of the vehicle 3 via the first connection 5. The electrical appliances of the vehicle 3 are therefore electrically connected to the high-voltage battery 2 via the first connection 5.

[0116] Control device 4 is connected to grounding device 26 on one hand. On the other hand, control device 4 is connected to high-voltage battery 2 via second connection 7. First connection 5 can be disconnected by control device 4 or re-established if necessary. For this purpose, a first switch 15, such as a bistable relay, is provided, which can be controlled by control device 4 via control command 20.

[0117] Even without the first supply voltage 13, the first switch 15 can keep the first connection 5 disconnected. That is, if the high-voltage battery 2 cannot provide sufficient first supply voltage 13, the first switch 15 will disconnect the high-voltage battery 2 from the intermediate circuit 6.

[0118] The first connection 5 can be disconnected by the control device 4 alone or re-established if necessary. The first switch 15 is therefore operated solely by the control device 4.

[0119] The control device 4 is connected to the high-voltage battery 2 via the first voltage converter 12. However, the control device 4 can also be connected directly to the high-voltage battery 2 without the first voltage converter 12.

[0120] The second supply voltage 14 generated by the first voltage converter 12 is lower than the first supply voltage 13 provided by the high-voltage battery 2 to the first voltage converter 12 and the intermediate circuit 6. In the third state, the control device 4 is connected to the intermediate circuit 6 only (and no longer to the high-voltage battery 2) via the first voltage converter 12.

[0121] The first voltage converter 12 is arranged between the high-voltage battery 2 and the control device 4, or between the second switch 16 and the control device 4.

[0122] The switching device 8 has a second switch 16, through which the control device 4 can be switched between the high-voltage battery 2 and the control device 4. The second switch 16 can disconnect only the high-voltage battery 2 from the control device 4.

[0123] The high-voltage battery 2 is connected to the second switch 16 via the second diode 10. The second diode 10 is arranged such that current can only flow from the high-voltage battery 2 to the second switch 16.

[0124] The second switch 16 and the first diode 9 are arranged such that, when the second connection 7 is established, only the control device 4 is connected to the high-voltage battery 2, wherein the control device 4 is permanently connected to the intermediate circuit 6 through the first diode 9.

[0125] The first diode 9 is arranged such that when the second connection 7 between the control device 4 and the high-voltage battery 2 is established, no (or virtually no) current can flow through the first diode 9 to the intermediate circuit 6.

[0126] Electrical connections 5 and 7 are designed such that current can flow from the high-voltage battery 2 to the intermediate circuit 6 in the absence of the first diode 9 and in the presence of the second connection 7 (but this is blocked by the first diode 9).

[0127] The second switch 16 and the second diode 10 are arranged such that when the second connection 7 between the control device 4 and the high-voltage battery 2 is established, no (or virtually no) current can flow through the second diode 10 to the high-voltage battery 2, nor is there any current supplied by the intermediate circuit 6.

[0128] Electrical connections 5 and 7 are designed such that, in the absence of the second diode 10 and in the presence of the second connection 7, current can flow from the intermediate circuit 6 and / or from the control device 4 to the high-voltage battery 2 (but this is blocked by the second diode 10).

[0129] The second connection 7 is formed by a MOSFET switch. The MOSFET switch has a gate terminal, a source terminal, and a drain terminal. Here, the control device 4 forms the gate terminal, and the high-voltage battery 2 and the control device 4 form one of the source terminal and the drain terminal, respectively.

[0130] The second connection 7 can be switched and / or established solely by the control device 4.

[0131] In the absence of the high-voltage battery 2 causing the first supply voltage 13, the first switch 15 can cause the first connection 5 to be disconnected.

[0132] The first connection 5 can be re-established solely by the control device 4. The first switch 15 is therefore operated solely by the control device 4 via control command 20. Control command 20 is here converted by amplifier circuit 11 to operate the second switch 16, which is designed as a MOSFET.

[0133] Control device 4 includes a system base chip 25. Communication between control device 1 and vehicle 3 is conducted via CAN 30 through system base chip 25. System base chip 25 has an LDO (low dropout) controller. If the output voltage is very similar to the input voltage, the LDO controller can adjust the output voltage. Through the LDO regulator, the microcontroller 28 of control device 4 can operate with a fourth supply voltage 31 via a third connection 29.

[0134] The microcontroller 28 is the core component of the control device 4 and controls all processes within the control device 4. The microcontroller 28 is connected to the analog front-end 27 via a communication channel. The analog front-end 27 detects the cell voltage, battery pack voltage, and battery pack current of the high-voltage battery 2.

[0135] The switching device 8 can be operated by the microcontroller 28. The first connection 5 and the second connection 7 can thus be re-established, especially independently of each other, by the operation of the first switch 15 and / or the second switch 16. The first switch 15 for switching the first connection 5 and the second switch 16 for switching the second connection 7 can be controlled or operated by the control command 20.

[0136] The current state of charge of the high-voltage battery 2 can be continuously determined during operation by control device 4 and / or microcontroller 28. This determination or detection can be performed using known methods, such as static voltage measurement and current integration and / or through a complex cell model.

[0137] In particular, the control device 4 and / or the microcontroller 28 can detect when the state of charge is below and / or above the limit value.

[0138] When the vehicle leaves the state of charge (SOC) range designated for normal operation of the high-voltage battery 2, a warning can be transmitted to the vehicle 3 via CAN 30 through the control device 4. Alternatively, erroneous inputs can be made, for example, in the control device 4, such as in its non-volatile memory 17.

[0139] Control device 1 ensures that control device 4 is connected to high-voltage battery 2 when sufficient energy is supplied through high-voltage battery 2. Here, when the charge level of high-voltage battery 2 falls below a first limit, high-voltage battery 2 can be disconnected from intermediate circuit 6 (disconnecting first connection 5) via control device 4.

[0140] Furthermore, control device 1 can ensure that control device 4 can also be disconnected from high-voltage battery 2 (disconnect second connection 7) when the charge state is below the second limit value of high-voltage battery 2. Here, control device 4 remains connected to intermediate circuit 6, so that control device 4 can start generator 22 with sufficient third supply voltage 19, for example, by means of a belt arranged in intermediate circuit 6.

[0141] According to step a) of the method, starting from the first state of the switching device 8, the current charging state of the high-voltage battery 2 is determined by the control device 4; and if the current charging state is lower than the second limit value, a third state is established according to step b).

[0142] Before step b), and following step i, step a) is executed, and...

[0143] If the current state of charge is below the first limit, proceed to step ii. to establish the second state, and proceed to step iii. to execute step a). If the current state of charge is below the second limit, proceed to step iv. to execute step b).

[0144] The second limit value is lower than the first limit value. This method is performed during the period when the state of charge of the high-voltage battery 2 decreases. This method protects the high-voltage battery 2 from deep discharge.

[0145] Follow step ii. Disconnect the first connection 5. This interrupts the first connection 5 between the high-voltage battery 2, the intermediate circuit 6, and the electrical appliances arranged in the vehicle 3, so that the high-voltage battery 2 does not continue to discharge through the vehicle 3.

[0146] After step ii., both high-voltage batteries (via the second connection 7) are connected to the control device 4. Furthermore, high-voltage batteries 2 (together with the control device 4) are connected to the intermediate circuit 6 via the first diode 9. However, current can only flow from the intermediate circuit 6 to both high-voltage batteries 2 and the control device 4. The control device 4 has significantly lower energy requirements than the vehicle 3. The vehicle 3 remains connected to the control device 4, or can continue to communicate with it, for example, via CAN 30.

[0147] If the value falls below the second limit, the second connection 7 is also disconnected, meaning the control device 4 is also disconnected from the high-voltage battery 2. Therefore, no electrical appliances are connected to the high-voltage battery 2 after step b).

[0148] Prior to step b), a status signal 18 is set in the non-volatile memory 17 of the control device 4. The status of the high-voltage battery 2 is stored in the control device 4 via this status signal 18 so that the status can be read from the control device 4, for example, via a service plug or a service device outside the vehicle. Alternatively or additionally, the status signal 18 can be transmitted to the central control unit 23 via CAN 30. By storing or transmitting the status signal 18, fault diagnosis of the high-voltage battery 2 can be performed even after the high-voltage battery 2 has been completely discharged and / or damaged.

[0149] After step b), the control device 4 no longer supplies voltage to the high-voltage battery 2, so that the high-voltage battery 2 is no longer discharged by the internal electronics of the control device 1. The high-voltage battery 2 can only self-discharge, wherein the self-discharge amount varies monthly, for example, within a maximum range of 2% of the rated state of charge.

[0150] The control device 1 ensures that when the charge level of the high-voltage battery 2 falls below a second limit, the control device 4 disconnects from the high-voltage battery 2 and remains connected (only) to the intermediate circuit 6. The control device 4 can then start the generator 22 via a belt arranged in the intermediate circuit 6 to operate with a sufficient third supply voltage 19.

[0151] After performing step b) and after the trial run of vehicle 3, a third supply voltage 19 is applied to intermediate circuit 6 through vehicle 3.

[0152] The test run of vehicle 3 includes starting the ignition system. During this process, the central control unit 23 is activated and it can be determined that the high-voltage battery 2 is no longer communicating with the central control unit 23, for example, via CAN 30.

[0153] If the control unit 23 confirms that no communication has occurred, the central control unit 23 can initialize the pre-charge of the intermediate circuit 6 to a determined voltage value via the second voltage converter 21 arranged in the intermediate circuit 6. A third supply voltage 19 can be applied to the control device 4 of the control unit 1 through the connection to the intermediate circuit 6. The third supply voltage 19 is applied to the first voltage converter 12, which then applies a second supply voltage 14 to the control device 4. The third supply voltage 19 is identical to the first supply voltage 13 in terms of voltage value.

[0154] A third supply voltage 19 from intermediate circuit 6 is applied to control device 4, enabling communication between control device 4 and central control unit 23 to be restored. Information from high-voltage battery 2 can thus be transmitted to central control unit 23.

[0155] By restoring communication between the control device 4 and the central control unit 23, the second voltage converter 21 can be configured to adjust the third supply voltage 19, so that the third supply voltage 19 in the intermediate circuit 6 is adjusted to the first supply voltage 13 of the high-voltage battery 2. After the third supply voltage 19 and the first supply voltage 13 are balanced, the first connection 5 can be reconnected, so that the high-voltage battery 2 is connected to the intermediate circuit 6.

[0156] The switch device 8 is operated by the control device 4, and the high-voltage battery 2 is connected to the intermediate circuit 6 via the first connection 5. The control command 20 for operating the switch device 8 is triggered by the control device 4 and / or the microcontroller 28.

[0157] Before the high-voltage battery 2 is connected to the intermediate circuit 6, the third supply voltage 19 existing in the intermediate circuit 6 is adjusted to the first supply voltage 13 of the high-voltage battery 2. After the first connection 5 is established, the high-voltage battery 2 is charged through the intermediate circuit 6.

[0158] The current charging state can be determined by control device 4, for example, based on the last stored state signal 18 and taking into account the self-discharge of the high-voltage battery 2. If control device 4 determines that the charging state is below the third limit value, the establishment of the first connection 5 is prevented.

[0159] A value below the third limit indicates that the high-voltage battery 2 is at least partially damaged, possibly irreversibly, thus preventing the establishment of the first connection 5. Specifically, the status signal 18 stored in the control device 4 enables the diagnosis of faults in the high-voltage battery 2.

[0160] After step b), the control device 4 is only reconnected to the high-voltage battery 2 via the second connection 7 when the high-voltage battery 2 reaches a charging state exceeding the fourth limit value. The second connection 7, i.e., the connection between the high-voltage battery 2 and the control device 4, i.e., the first state, is only re-established when the high-voltage battery 2 reaches a sufficient charging state to ensure a first supply voltage 13 is supplied to the control device 4. The second connection 7 is re-established by the control device 4.

[0161] List of reference numerals in the attached diagram:

[0162] 1. Control device

[0163] 2. High-voltage battery

[0164] 3 Motor vehicles

[0165] 4. Control equipment

[0166] 5 First Connection

[0167] 6. Intermediate Circuit

[0168] 7 Second Connection

[0169] 8 Switching device

[0170] 9 First Diode

[0171] 10 Second Diode

[0172] 11 Amplifier Circuit

[0173] 12 First Voltage Converter

[0174] 13 First Supply Voltage

[0175] 14 Second Supply Voltage

[0176] 15 First Switch

[0177] 16 Second Switch

[0178] 17. Memory

[0179] 18 Status Signals

[0180] 19 Third supply voltage

[0181] 20 Control Commands

[0182] 21 Second Voltage Converter

[0183] 22. Belt-driven generator

[0184] 23 Control Unit

[0185] 24 subnetworks

[0186] 25 System Base Chips

[0187] 26 Grounding device

[0188] 27 Simulated Front End

[0189] 28 microcontrollers

[0190] 29 Third Connection

[0191] 30 CAN

[0192] 31 Fourth supply voltage

Claims

1. A control device (1) for a high-voltage battery (2) in a motor vehicle (3), comprising at least a high-voltage battery (2) and a control device (4) for the high-voltage battery (2); wherein, The high-voltage battery (2) is connected to the intermediate electrical circuit (6) of the motor vehicle (3) via a switchable first electrical connection (5) and to the control device (4) via a switchable second electrical connection (7); wherein the control device (1) has a switching device (8) by which the first connection (5) and the second connection (7) can be switched, such that in the first state of the switching device, the high-voltage battery (2) is connected to the intermediate circuit (6) and the control device (4) is connected to the high-voltage battery (2); wherein in the second state, the high-voltage battery (2) is disconnected from the intermediate circuit (6) and the control device (4) is connected to the high-voltage battery (2), and in the third state, the control device (4) is disconnected from the high-voltage battery (2) and connected to the intermediate circuit (6); wherein the control device (4) is connected to the intermediate circuit (6) via a first diode (9) such that current can only flow from the intermediate circuit (6) to the control device (4), wherein the control device (4) is connected to the intermediate circuit (6) in all states.

2. The control device (1) according to claim 1, wherein, The control device (4) is connected to the high-voltage battery (2) via a first voltage converter (12), wherein the second supply voltage (14) generated by the first voltage converter (12) is lower than the first supply voltage (13), and the first supply voltage is provided by the high-voltage battery (2) to the first voltage converter (12) and the intermediate circuit (6); wherein, in the third state, the control device (4) is connected to the intermediate circuit (6) via the first voltage converter (12) and the first diode (9).

3. The control device (1) according to claim 1, wherein, The switching device (8) has a first switch (15) for establishing a first connection (5), wherein the intermediate circuit (6) is switchably connected to the high-voltage battery (2) via the first switch (15).

4. The control device (1) according to claim 3, wherein, The switching device (8) has a second switch (16) for establishing a second connection (7), and the control device (4) is switchably connected to the high-voltage battery (2) via the second switch.

5. The control device (1) according to claim 4, wherein, The second switch (16) can only be switched by the control device (4).

6. The control device (1) according to any one of claims 4 and 5, wherein, The high-voltage battery (2) is connected to the second switch (16) via the second diode (10) so that current can only flow from the high-voltage battery (2) to the second switch (16).

7. The control device (1) according to claim 4, wherein, The second switch (16) and the first diode (9) are arranged to control only the connection of the device (4) to the high-voltage battery (2) when the second connection (7) is established.

8. The control device (1) according to claim 4, wherein, At least the first connection (5) or the second connection (7) is formed by a MOSFET switch.

9. A method for operating the control device (1) according to any one of the preceding claims; wherein, Starting from the first state of the switching device (8), the method includes at least the following steps: a) The current charging state of the high-voltage battery (2) is determined by the control device (4); and If the current charging status is below the limit value b) Establish the third state.

10. The method according to claim 9, wherein, Perform the following steps before step b): i. Perform step a) and If the current charging state is below the first limit value ii. Establish the second state, and iii. Perform step a) and If the current charging state is below the second limit value iv. Perform step b).

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