DE102018006582B4 - Battery for a motor vehicle and vehicle electrical system - Google Patents

Abstract

Battery (1) for a motor vehicle (10), comprising an electrochemical energy store (20), a battery management system (24), a power switching element (23) and a first circuit device (33), which are arranged in a common battery housing, further comprising at least one ground connection (21, 31), a first supply voltage connection (22) and a second supply voltage connection (32), which are led out of the battery housing, wherein a positive pole (201) of the energy store (20) is switchably connected to the first supply voltage connection (22) via the power switching element (23) and wherein the power switching element (23) can be controlled by the battery management system (24), and wherein the second supply voltage connection (32) is electrically connected to the positive pole (201) of the energy store (20) via the first circuit device (33), wherein the first circuit device (33) comprises a power transistor (3310), a measuring device (3311) and a Driver logic (3312), wherein the measuring device (3311) is designed to detect a load current flowing through the power transistor (3310) in order to form a current limiting device in cooperation with the driver logic (3312) and the power transistor (3310), and wherein the first circuit device (33) is further designed to detect a current pulse by means of the measuring device (3311) and to send a wake-up signal to the battery management system (24) as a function of a detected current pulse.

Description

The present invention relates to a battery for a motor vehicle, a motor vehicle electrical system and a motor vehicle.

Motor vehicle electrical systems are conventionally equipped with a lead-acid battery, which, in the example of a passenger car (car), provides a nominal battery voltage of 12 V. The battery is used to start an internal combustion engine and to supply electrical consumers of the motor vehicle electrical system if no or insufficient electrical power is provided by an internal combustion engine-operated generator.

For future vehicle applications, particularly with regard to the desired CO2 and fuel savings, vehicle batteries with a cell system based on lithium-ion (Li-ion) technology are becoming increasingly important. Compared to conventional lead-acid batteries, vehicle batteries with Li-ion cells have a higher energy storage density, which can be used to reduce weight. Furthermore, Li-ion cells have a higher charge acceptance than lead-acid batteries, which is particularly advantageous for storing recuperated braking energy.

In addition to the above and other advantages, electrochemical cell systems based on Li-ion technology also have some critical properties. Lithium-ion cells are particularly less resistant to overcharging and overcurrents than conventional lead-acid batteries. Li-ion batteries for motor vehicles are therefore equipped with a battery management system (BMS) that is arranged in a common housing together with a circuit breaker and the electrochemical energy storage device, i.e. a number of interconnected Li-ion cells. Two connection terminals lead out of the battery housing, via which a supply voltage and a ground potential are provided for a vehicle electrical system. The supply voltage connection is switchably connected to the positive pole of the Li-ion cells via the circuit breaker, and the ground connection to the negative pole. The BMS includes a microprocessor system and various measuring devices with which numerous battery or cell parameters can be monitored. The BMS is also equipped with a data interface for connection to a CAN or LIN bus of a vehicle's on-board network, for example, so that communication with the energy or generator management and other control devices is possible. The BMS is particularly designed to determine the current state of charge (SoC) of the Li-ion battery. If an overcharge or overcurrent cannot be corrected via the energy management, the circuit breaker can be disconnected for safety reasons.

In addition to low resistance to overcharging and overcurrent, Li-ion batteries are also sensitive to deep discharge, which can lead to cell damage and a shortened service life or immediate failure of the battery. When a vehicle is parked, it can therefore be problematic that many of the control units distributed in the vehicle's on-board network are put into a standby state, which continues to consume electrical current. Depending on the vehicle model and equipment, the current consumption in a vehicle's on-board network can add up to between 5 mA and 25 mA, for example. This standby mode can become critical for a Li-ion battery in the vehicle's on-board network, for example, if the vehicle is parked for a longer period of time, for example weeks or months, during which the battery could be discharged beyond a deep discharge threshold.

From the EN 10 2012 211 393 A1 A Li-ion battery for a motor vehicle with a deep discharge protection function is known, which is provided by the interaction of an integrated circuit breaker and a BMS. The circuit breaker can be opened as soon as the BMS detects that a battery parameter has fallen below a respective deep discharge threshold. By opening the circuit breaker, all power consumers in the vehicle's electrical system are disconnected from the battery cells. In order to efficiently reduce further discharge after a deep discharge protection shutdown, the integrated BMS can also be disconnected from the battery cells.

The EN 10 2011 122 042 A1 describes a motor vehicle electrical system with a vehicle battery that has an electrochemical energy storage device and a first and a second isolating switch for a first and a second circuit. A first control unit within the motor vehicle electrical system can control the first isolating switch via an opening signal in order to open the isolating switch. The first isolating switch can be controlled via a closing signal from a second control unit so that the first isolating switch is closed again. A supply voltage for the second control unit is provided by means of the second circuit even when the first circuit is opened via the first isolating switch.

The EN 10 2016 123 131 A1 describes a battery management system for a vehicle. A controller can disconnect a consumer circuit from a vehicle battery using a relay. Based on a wake-up signal, the controller can control the relay and close the consumer circuit again.

A disadvantage of the current state of the art is that a vehicle battery that has been switched off must first be manually reactivated by a vehicle user before any of the vehicle's electrical functions are available. Automated reactivation of a vehicle battery, on the other hand, requires the respective control device to be permanently operated in standby mode in order to be able to receive and process a corresponding wake-up signal.

The present invention therefore has the object of providing an improved deep discharge protection for a vehicle battery, which in particular meets the user-friendliness in connection with long-term parking processes, i.e. when parking a vehicle for a period of, for example, one month or longer.

Accordingly, a battery for a motor vehicle is proposed according to the independent main claim and by an on-board network for a motor vehicle and by a motor vehicle according to the auxiliary claims. Further embodiments are the subject of the respective subclaims.

According to a first aspect of the invention, the object is achieved by a battery for a motor vehicle, which comprises an electrochemical energy store, a battery management system, a power switching element and a first circuit device, which are arranged in a common battery housing. The battery further comprises at least one ground connection, a first voltage connection and a second voltage connection, which are led out of the battery housing. A positive pole of the energy store is switchably connected to the first voltage connection via the power switching element and the power switching element can be controlled by the battery management system. The second voltage connection is electrically connected to the positive pole of the energy store via the first circuit device.

The first circuit device comprises a power transistor, a measuring device and a driver logic, which is designed to detect a load current flowing through the power transistor (3310) in order to form a current limiting device in cooperation with the driver logic (3312) and the power transistor (3310).

The first circuit device is further designed to detect a current pulse by means of the measuring device and to send a wake-up signal to the battery management system as a function of a detected current pulse.

An electrochemical energy storage device comprises at least one group with a number of electrochemical cells connected in series. The positive pole of the energy storage device is the positive pole of the series connection of the electrochemical cells, the negative pole is the negative pole of this series connection, which is preferably defined as a reference or ground potential. The battery voltage is provided between the positive and negative poles of the energy storage device, which is led out of a battery housing via connection terminals for the first and second voltage connection and the ground connection. The electrochemical cells are preferably Li-ion cells.

A battery management system comprises electronic circuits for controlling and regulating charging and discharging processes of the electrochemical energy storage device or its individual cells. The battery management system can contain a microprocessor system with which battery parameters such as battery voltage, individual cell voltages, temperatures and/or currents are recorded and processed in order to determine other parameters such as the state of charge of the battery. If a critical limit is reached for at least one parameter, the electronics or microprocessor of the battery management system can control the power switching element so that the electrochemical energy storage device can be disconnected from at least one connection terminal leading out of the battery housing and thus also from a connected vehicle electrical system.

The power switching element is preferably designed in the form of an electromechanical contactor, a so-called main contactor. In principle, a power semiconductor switch can also be used here, provided that currents of typically 800 A or current peaks of typically up to 1400 A can be reliably separated. A power switching element can also be designed with two poles, so that in addition to the first voltage connection, an associated ground connection can also be separated from the energy storage device at the same time.

According to this first aspect of the invention, a second voltage connection is provided on the battery, which is not affected at least in certain cases of a shutdown of the first voltage connection initiated by the battery management system. An electrical energy supply for selected consumers can thus be provided via this second voltage connection. When the power switching element is disconnected to protect the battery from deep discharge, it is sensible to only supply electrical consumers for the most necessary functions. The maximum current that can be delivered via the second voltage connection is therefore limited, so that further discharging of the electrochemical energy storage device can also be reduced to a minimum.

In addition to the known standby mode and a complete shutdown of the vehicle electrical system when the battery reaches or falls below a critical charge level, the present invention provides a long-term standby mode with which at least a minimal vehicle electrical system function with low power consumption can be provided.

A further idea behind the present invention is to provide a convenient way to end a long-term standby mode or to reactivate a respective vehicle electrical system. A current pulse represents a simple way of communicating between a control unit connected to the second supply voltage connection, e.g. that of the central locking system, and battery electronics. In connection with a central locking module of the vehicle, the current pulse that is generated when corresponding actuators are activated can be used as an implicit wake-up signal, so that no extra signal needs to be generated.

According to a development of the first aspect of the invention, the battery management system can comprise a timer and a data interface. The battery management system can also be designed to start the timer depending on first vehicle operating state information received via the data interface. The battery management system can also be designed to control the power switching element depending on an expired timer in order to electrically separate the positive pole of the energy storage device from the first electrical voltage connection.

The idea behind this development is to provide preventive deep discharge protection for a motor vehicle battery, which is preferably triggered when the charge level is above a critical lower charge level. This means that a sufficient charge can be retained in the battery to start an engine in a motor vehicle, which can be accessed via the first voltage connection after the battery has been reactivated.

Vehicle operating status information can be, for example, a locking signal from a central locking control unit, which can be seen as a characteristic signal for the start of a parking process. An expiration time of the timer can be selected in such a way that the power switching element only disconnects the first voltage connection from the battery voltage when a motor vehicle is parked for a longer period of time during which there is a risk of the battery being completely discharged. If, for example, an expiration time of 30 days is selected, normal restarting and starting of the vehicle from standby mode is possible.

According to an alternative or additional development, the battery management system can be designed to detect a state of charge of the energy storage device and to control the power switching element depending on whether a first state of charge threshold is undershot in order to disconnect the electrical connection between the positive pole of the energy storage device and the electrically first voltage connection.

The first charge level threshold can advantageously be selected such that a charge level remains in the energy storage device of the battery which is at least sufficient for starting the engine of a motor vehicle without the energy storage device reaching a critical deep discharge state.

According to a further embodiment of the first aspect of the invention, the battery management system can further be assigned a second circuit device which is designed to interrupt a supply voltage at least for parts of the battery management system as a function of a separate power switching element.

The battery management system with an integrated microprocessor and associated circuit devices for recording and processing measured physical operating parameters also represents a consumer that continues to consume electrical power in standby mode, which must be provided by the electrochemical energy storage device of the battery. With an interruption of the supply voltage, at least for parts of the battery management system, depending on a separate power switching element, the discharge of the energy storage device can be further reduced.

According to a further development, a monitoring device can also be provided which is designed to detect a voltage across the number of battery cells connected to one another and to compare it with a lower voltage threshold value.

Even in a long-term standby mode, a lower charge level threshold can be continuously monitored in order to counteract damage to the electrochemical energy storage device or impending cell defects. The lower charge level threshold can be monitored using a corresponding minimum voltage value between the positive and negative poles of the energy storage device. The monitoring device provides deep discharge monitoring that is independent of the battery management system, with which the charge level of the battery can be continuously calculated and monitored. The battery management system can therefore be deactivated during a long-term standby mode.

In addition, the monitoring device can be designed to control the first circuit device in order to electrically disconnect the positive pole of the energy storage device from the second voltage connection when the lower voltage threshold is undershot.

When a critical lower state of charge threshold is reached, a long-term standby mode can be terminated so that the battery or its cells are protected from further discharge.

According to a further development, the monitoring device can comprise an analog comparator circuit with at least one operational amplifier and a reference voltage switching device.

Corresponding analog circuits are characterized by a current consumption in the range of a few µA, while a microprocessor-based battery management system requires between 1-3 mA during operation. This provides energy-saving deep discharge protection, especially for a long-term standby mode.

According to a further development, the driver logic can be designed to control the power transistor depending on the load current and depending on the voltage falling below the lower threshold value.

The power transistor, in conjunction with the associated measuring device and driver logic, combines a current limiting device with a power switch in a semiconductor component. The power transistor, measuring device and driver logic can preferably be combined in a monolithic integrated circuit (IC).

According to a second aspect of the invention, the object is achieved by a motor vehicle electrical system which comprises a first sub-electrical system with a first voltage supply line, a second sub-electrical system with a second voltage supply line and a battery according to the first aspect of the invention. The first voltage supply line of the first sub-electrical system is connected to a first supply voltage connection of the battery. The second voltage supply line is connected to a second supply voltage connection of the battery. The second voltage supply line is designed for a lower maximum current than the first voltage supply line.

According to an idea behind the second aspect of the invention, the second sub-vehicle network is intended to supply electrical energy to selected control devices which, during a long-term standby mode, have a lower total power or current consumption than the sum of all control devices during a conventional standby mode. The design for a lower maximum current makes it possible to provide smaller line cross-sections for the second voltage supply line than for the first voltage supply line, at least in a line section between the first supply voltage connection of the battery and a first fuse box.

According to a third aspect of the invention, the object is achieved by a motor vehicle with a motor vehicle electrical system according to the second aspect of the invention.

• 1 ein Kraftfahrzeug mit einem Kraftfahrzeugbordnetz und einer Fahrzeugbatterie;
• 2 eine Fahrzeugbatterie;
• 3 eine erste Ausgestaltung einer ersten Schaltungseinrichtung der Fahrzeugbatterie;
• 4 eine zweite Ausgestaltung einer ersten Schaltungseinrichtung der Fahrzeugbatterie.

Further features and details emerge from the following description, in which - if necessary with reference to the drawing - at least one embodiment is described in detail. Described and/or illustrated features form the subject matter on their own or in any meaningful combination, possibly also independently of the claims, and can in particular also be the subject of one or more separate applications. Identical, similar and/or functionally identical parts are provided with the same reference numerals. Shown are:

• 1 a motor vehicle with a vehicle electrical system and a vehicle battery;
• 2 a vehicle battery;
• 3 a first embodiment of a first circuit device of the vehicle battery;
• 4 a second embodiment of a first circuit device of the vehicle battery.

In the 1 a motor vehicle 10 with a battery 1 according to the invention and a motor vehicle electrical system according to the invention is shown schematically. The motor vehicle electrical system comprises two sub-electrical systems, wherein a first sub-electrical system extending to the left of the battery has a first supply line 2 which is connected to a first supply voltage connection 22 of the battery 1. A second sub-electrical system with a second supply line 3 is shown to the right of the battery 1. The motor vehicle electrical system can have a common ground potential for both sub-electrical systems, wherein an electrically conductive body can function as a ground line.

Both sub-vehicle networks each provide a 12 V nominal supply voltage for supplying electrical energy to electrical vehicle components. A significant difference between the first and second sub-vehicle networks is that the second supply line 3 and the second supply voltage connection 32 of the battery 1 are designed for a lower maximum current than the first supply line 2 and the first supply voltage connection 22 of the battery 1. The second supply voltage connection 32 of the battery 1 thus represents, according to the invention, an additional low power outlet (LPO) of the battery 1.

Numerous electrical vehicle components are connected to the first supply line 2, with a generator 7 and a resistor being shown as examples. The resistor represents a large number of electronic control units or other electrical consumers 8 of the vehicle's on-board network that require electrical energy.

The supply lines for the generator 7 and the electrical consumers 8 are each protected by fuses 9 to protect against overcurrents.

The second supply line 3 provides an electrical power supply for a central locking module 5. The central locking module 5 is equipped with a radio receiver that can receive a radio signal 40 from a key remote control.

The vehicle electrical system also includes a data transmission network, which can be designed as a CAN or LIN bus system and enables communication between numerous electronic control units in the vehicle electrical system. In particular, the central locking module 5 and the battery 1 are connected to the data line 4 of the data transmission network.

The 2 shows a battery 1 according to the invention for a motor vehicle 10, which comprises a first pair of terminals for providing a battery voltage for the first partial on-board network. The 12 V nominal supply voltage is provided by a series connection of a number of Li-ion cells, which form the electrochemical energy storage device 20 of the battery. A negative pole of the electrochemical energy storage device 20 is electrically connected to a ground connection 21 of the first pair of terminals. An electrical connection of a positive pole 201 of the energy storage device 20 to the first voltage connection 22 is switchable via a power switching element 23.

The battery 1 further comprises a battery management system (BMS) 24, which is used to monitor, regulate and protect the electrochemical energy storage device 20 or each of its Li-ion cells. The BMS 24 comprises a microcontroller system with associated measuring electronics, with which, for example, the battery current and the voltages and temperatures of the individual lithium-ion cells or those of the entire electrochemical energy storage device 20 can be recorded and monitored. The microcontroller system is set up to process the measured values recorded by measurement so that the current state of charge (SoC) of the energy storage device 20 with the lithium-ion cells can be determined. The microcontroller system provides a data interface 14, which leads out of a housing of the battery 1 and can be connected to the CAN or LIN-based data line 4 in a motor vehicle 10. In cooperation with a control device of a generator 7, the BMS 24 can provide charge management for the battery 1.

The BMS 24 is connected to the power switching element 23 via a first control line 25 in order to provide various protective functions for the electrochemical energy storage device 20 or the lithium-ion cells. The positive pole 201 of the energy storage device 20 can be electrically separated from the first supply voltage connection 22 by the BMS 24 by controlling the power switching element 23. In connection with a deep discharge protection function mentioned at the beginning, the BMS 24 controls the power switching element element 23 and disconnects the positive pole 201 of the energy storage device 20 from the first supply voltage connection 22 as soon as a lower threshold value for the SoC of the battery 1 is reached.

The power switching element 23 can be designed as an electromechanical switch, for example as a contactor. The contactor, which is also referred to as the main contactor of a battery, can also be designed with two poles, so that the positive pole 201 and the negative pole 202 of the energy storage device 20 can be electrically separated from the first supply voltage connection 22 and from the ground connection 21 of the first connection terminal pair. The power switching element 23 can also be designed as a power semiconductor switch.

The battery 1 according to the invention comprises a second supply voltage connection 32, which is switchably connected to the positive pole 201 of the energy storage device 20 via a first circuit device 33. A second ground connection 31 can be assigned to the second supply voltage connection 32, so that a second pair of connection terminals is provided.

The second supply voltage connection 32 provides an additional low power outlet (LPO) of the battery 1, with which current and voltage can be supplied independently of the first supply voltage connection 22 to supply selected on-board network components, for example the 1 shown central locking module 5. The same nominal battery voltage of 12 V is provided from the energy storage device 20 at the first supply voltage connection 22 and the second supply voltage connection 32. The difference between the voltage connections is that the second supply voltage connection 32 is limited to a maximum output current that is much smaller than the maximum output current of the first supply voltage connection 22. The first supply voltage connection 22 can, for example, provide output currents of up to 800 A, with current peaks of up to 1400 A being possible. During standby operation of a motor vehicle, up to 25 mA of continuous current can be supplied to the motor vehicle electrical system.

The second supply voltage connection 32 is intended for a permanent current output of a maximum of 2 mA, whereby a current limiting device of the first circuit device 33 is intended to allow higher currents for a short time.

The BMS 24 of the battery 1 is set up to switch the battery 1 from a standby mode to a long-term standby mode as soon as a switching criterion for this has been met. A switching criterion is the expiration of a timer, for example of 30 days. The timer is started when the BMS 24 receives a locking signal from the central locking module 5 via the data interface 14 from the CAN or LIN bus. If an unlocking signal is received from the central locking module 5 via the data interface 14 before the timer expires, the timer is stopped or reset. If the timer expires, the switching criterion is met and the BMS 24 controls the power switching element 23 via the control line 25 so that a current output of 5 mA-25 mA via the first supply voltage connection 22 is interrupted. The central locking module 5 is supplied with a continuous current requirement of 1 mA to 2 mA during its readiness to receive via the second supply voltage connection 32.

The BMS 24 is preferably at least partially deactivated during a long-term standby mode in order to reduce the current provided by the energy storage device 20 to between 1 mA and 3 mA. When the microcontroller system is deactivated, the BMS 24 can no longer monitor a critical lower SoC. In order to provide a deep discharge protection function even during a long-term standby mode, an additional monitoring device 34 is provided. This comprises, for example, an analog comparator circuit with an operational amplifier and a reference voltage circuit device with which it is possible to detect when a lower voltage value of the energy storage device 20 is reached. The lower voltage value corresponds to a critical lower SoC. If the lower voltage value is reached, the first circuit device 33 is controlled via the third control line 36 so that the second supply voltage connection 32 is electrically separated from the positive pole 201 of the energy storage device 20. In this case, the long-term standby mode is ended in favor of a deep discharge protection shutdown.

If the central locking module 5 receives a radio signal 40 with an unlocking command from a key remote control (not shown in the figures) during a long-term standby mode, corresponding central locking actuators (not shown in the figures) can be controlled by the central locking module 5 in the motor vehicle 10 to unlock the doors. A control pulse emitted by the central locking module 5 causes its current consumption to rise briefly to a value above the 1-2 mA prevailing during the standby mode. The current drawn from the battery 1 via its second supply voltage connection 32 The current pulse given for unlocking the motor vehicle 10 could be detected in the first circuit device 33 or in the monitoring device 34 with corresponding circuit devices, so that a signal for reactivating the BMS 24 can be output via the second control line 35 or via the fourth control line 37.

The long-term standby mode can thus be conveniently ended by receiving an unlocking command from the key remote control, in which the at least partially deactivated BMS 24 is woken up by the central locking module 5. The reactivated BMS 24 can control and close the power switching element 23 via the first control line 25, so that the supply voltage for the first supply line 2 is provided again via the first supply voltage connection 22.

Alternatively, the BMS 24 can be woken up directly by the central locking module 5 by integrating a wake-up function in a transceiver for the data interface 14 of the BMS 24. During a long-term standby mode, no signals can be exchanged via the data line 4. If the central locking module 5 receives and verifies a valid unlocking command, a wake-up signal can be sent to the BMS 24 of the battery 1 via the data line 4.

In the 3 is a first embodiment of the first circuit device 33 of a battery 1 according to the invention. The first circuit device 33 comprises an input voltage contact 331 which can be connected or is connected to the positive pole 201 of the energy storage device 20. An output voltage contact 332 can be connected or is connected to the second supply voltage connection 32. A signal input 333 is used for the electrical connection to the monitoring device 34 via the third control line 36. The first circuit device 33 contains a power switch 336 which is designed, for example, as a relay or as a semiconductor switch. If a signal for a deep discharge protection shutdown is present at the signal input 333, the power switch 336 separates the input voltage contact 331 from the output voltage contact 332.

The first circuit device 33 also contains a fuse 335, for example a safety fuse with a nominal current of 2 mA. The safety fuse preferably has a slow-blow characteristic so that an output current of the second supply voltage connection 32 of the battery 1 limited to 2 mA can be exceeded for a short time. A diode 337 can be provided for safety reasons in order to suppress an erroneous, i.e. undesirable, charging current via the second supply voltage connection 32.

The 4 shows an alternative second embodiment of the first circuit device 33, which essentially consists of an integrated so-called smart high-side power switch. A smart high-side power switch is essentially an integrated circuit with a power MOS transistor for controlling a supply voltage and control and diagnostic electronics. The 4 The alternative integrated first circuit device 33 shown comprises an input voltage contact 331, an output voltage contact 332 and a signal input 333, which are functionally equivalent to the terminals of the already described with reference to 3 described first embodiment.

The integrated circuit has a power MOS transistor 3310, with which a voltage provided by the energy storage device 20 can be switched through from the input voltage contact 331 to the output voltage contact 332. The load current flowing through the power MOS transistor 3310 can be continuously monitored using a measuring device 3311. In conjunction with a driver logic 3312 for controlling the power MOS transistor 3310, the measuring device 3311 can provide a current limit for the second supply voltage connection 32 of the battery 1. A current pulse for unlocking the motor vehicle 10 could also be detected in conjunction with the measuring device 3311 and the driver logic 3312, so that a signal for waking up the BMS 24 can be output via a signal output 334.

Although the subject matter has been illustrated and explained in detail by means of embodiments, the invention is not limited by the disclosed examples and other variations can be derived from them by the person skilled in the art. It is therefore clear that a large number of possible variations exist. It is also clear that embodiments mentioned as examples only represent examples that are not to be understood in any way as a limitation of the scope of protection, the possible applications or the configuration of the invention. Rather, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete terms, whereby the person skilled in the art, with knowledge of the disclosed inventive concept, can make a variety of changes, for example with regard to the function or arrangement of individual elements shown in an exemplary embodiment. mentioned elements without departing from the scope of protection defined by the claims and their legal equivalents, such as further explanations in the description.

List of reference symbols

1

battery

2

first supply line

3

second supply line

4

Data line

5

Central locking module

6

Backup

7

generator

8

consumer

9

Backup

10

Motor vehicle

14

Data interface

20

electrochemical energy storage

201

positive pole

202

negative pole

21

Ground connection

22

first supply voltage connection

23

Power switching element

24

Battery management system (BMS)

25

first control line

31

Ground connection

32

second supply voltage connection

33

first circuit device

34

Monitoring device

35

second control line

36

third control line

37

fourth control line

331

Input voltage contact

332

Output voltage contact

333

Signal input

334

Signal output

335

Backup

336

Circuit breaker

337

diode

3310

Power MOS transistor

3311

Measuring device

3312

Driver logic

Claims (10)

Battery (1) for a motor vehicle (10), comprising an electrochemical energy store (20), a battery management system (24), a power switching element (23) and a first circuit device (33), which are arranged in a common battery housing, further comprising at least one ground connection (21, 31), a first supply voltage connection (22) and a second supply voltage connection (32), which are led out of the battery housing, wherein a positive pole (201) of the energy store (20) is switchably connected to the first supply voltage connection (22) via the power switching element (23) and wherein the power switching element (23) can be controlled by the battery management system (24), and wherein the second supply voltage connection (32) is electrically connected to the positive pole (201) of the energy store (20) via the first circuit device (33), wherein the first circuit device (33) comprises a power transistor (3310), a measuring device (3311) and a Driver logic (3312), wherein the measuring device (3311) is designed to detect a load current flowing through the power transistor (3310) in order to form a current limiting device in cooperation with the driver logic (3312) and the power transistor (3310), and wherein the first circuit device (33) is further designed to detect a current pulse by means of the measuring device (3311) and to send a wake-up signal to the battery management system (24) as a function of a detected current pulse. Battery according to the above Claim 1 , wherein the battery management system (24) comprises a timer and a data interface (14), wherein the battery management system (24) is designed to start the timer depending on a first vehicle operating state information received via the data interface (14), and wherein the battery management system (24) is further designed to control the power switching element (23) depending on an expired timer in order to electrically disconnect the positive pole (201) of the energy store (20) from the first supply voltage connection (22). Battery according to one of the preceding Claims 1 or 2 , wherein the battery management system (24) is designed to detect a state of charge of the energy storage device (20) and to control the power switching element (23) depending on a first state of charge threshold being undershot in order to establish the electrical connection between between the positive pole (201) of the energy storage device (20) and the first supply voltage terminal (22). Battery according to one of the preceding Claims 1 until 3 , wherein the battery management system (24) is further assigned a second circuit device which is designed to interrupt a supply voltage at least for parts of the battery management system (24) depending on a separate power switching element (23). Battery according to one of the preceding Claims 1 until 4 , further comprising a monitoring device (34) which is designed to detect a voltage between the positive pole (201) and a negative pole (202) of the energy store (20) and to compare it with a lower voltage threshold value. Battery according to the above Claim 5 , wherein the monitoring device (34) is further designed to control the first circuit device (33) in order to electrically separate the positive pole (201) of the energy store (20) from the second supply voltage connection (32) when the lower voltage threshold value is undershot. Battery according to one of the preceding Claims 5 or 6 , wherein the monitoring device (34) comprises an analog comparator circuit with at least one operational amplifier and a reference voltage circuit device. Battery according to one of the preceding Claims 5 until 7 , wherein the driver logic (3312) is designed to control the power transistor (3310) depending on the voltage falling below the lower threshold value. Motor vehicle electrical system comprising a first sub-electrical system with a first voltage supply line (2), a second sub-electrical system with a second voltage supply line (3) and a battery (1) according to one of the preceding Claims 1 until 8 , wherein the first voltage supply line (2) is connected to a first supply voltage terminal (22) of the battery (1) and wherein the second voltage supply line (3) is connected to a second supply voltage terminal (32) of the battery (1), wherein the second voltage supply line (3) is designed for a lower maximum current than the first voltage supply line (2). Motor vehicle comprising a motor vehicle electrical system according to the above Claim 9 .

Images