DE102021129775A1 - System for providing energy for a vehicle and method for operating such a system - Google Patents

Abstract

The invention relates to a system for providing energy for a vehicle (11), comprising a multipack arrangement (20) with at least a first battery pack (22) and a second battery pack (24, 26) and with the multipack arrangement (20 ) coupled multipack control unit (30). A pack control unit (23, 25, 27) is assigned to the first (22) and the second battery pack (24, 26). The pack control units (23, 25, 27) are set up to record a battery parameter of the respectively assigned battery pack (22, 24, 26). The multipack control unit (30) is set up to receive the battery parameters of the respectively assigned battery packs (22, 24, 26) detected by the pack control devices (23, 25, 27) and to assign a parameter target value based on the received battery parameters determine and transmit to at least one of the battery packs (22, 24, 26). The pack control devices (23, 25, 27) are also set up to use the received parameter target value to carry out a voltage equalization for the respectively assigned battery pack (22, 24, 26). In the method, a pack control unit (23, 25, 27) is assigned to the first (22) and the second battery pack (24, 26). A battery parameter of the battery pack (22, 24, 26) assigned in each case is recorded, a target parameter value is determined on the basis of the received battery parameters and a charge equalization for the battery pack (22, 24, 26) assigned in each case is carried out on the basis of the target parameter value received .

Description

The invention relates to a system for providing energy for a vehicle and a method for operating such a system

Batteries and battery packs that supply electrical components with electricity are installed in modern vehicles, in particular with an electric drive. In this case, a high voltage of, for example, 400 V or 800 V is provided in particular.

Corresponding battery packs include several battery cells that can be connected in different ways. A typical challenge when using such a system is to operate all battery cells and battery packs involved with sufficiently similar voltage levels. Irregularities can lead to an uneven distribution of voltage values within the system and reduce the life of the batteries. If the difference in the voltage levels is too great, a battery pack can no longer be interconnected with other battery packs, which leads to a loss of performance in the overall system.

Various options have been proposed for carrying out a voltage equalization of the battery cells and thus ensuring an even voltage level within a battery pack.

Also describes the U.S. 2016/0297318 A1 a method of describing the degree of degradation of a secondary battery when charged and discharged at a prescribed frequency. In this case, an upper limit current value at the time of charging or discharging is determined based on an estimated SOC and a target degree of degradation.

From the DE 10 2019 132 640 A1 a traction battery pack balancing system is known.

The DE 10 2018 004 891 A1 describes a method for voltage equalization in the electrical system of an electrically powered vehicle. A target voltage range is established and the battery devices of the vehicle are discharged by switching on until their voltage is within a target voltage range.

From the DE 10 2018 131 450 A1 a hybrid electric vehicle is known which has battery packs coupled in parallel to the vehicle with cells connected in series. Cell voltage, current and temperature are sensed and contactors are opened to adjust the state of charge of unbalanced cells until they are balanced with respect to the others.

It is the object of the invention to provide a system of the type described at the outset and a method for its operation, in which the balancing of the voltages provided by the batteries takes place in a particularly simple and efficient manner. In order to obtain the full usable capacity, the battery cells should be kept at the same high state of charge as possible. In addition, energy losses during compensation should be minimized and the hardware effort should be kept low.

This object is solved by a system and a method having the features of the independent claims. Advantageous refinements and developments of the invention are specified in the dependent claims.

The system for providing energy for a vehicle comprises a multipack arrangement with at least a first battery pack and a second battery pack and a multipack control unit coupled to the multipack arrangement. A pack control unit is assigned to the first and the second battery pack. The pack control devices are set up to record at least one battery parameter of the respectively assigned battery pack. The multipack control unit is set up to receive the battery parameters of the respectively assigned battery packs detected by the pack control devices and to determine at least one parameter target value based on the received battery parameters and to at least one of the battery packs or to the pack control device assigned to the battery pack transferred to. The pack control devices are also set up to use the received parameter target value to carry out a voltage equalization for the respectively assigned battery pack.

This allows voltage balancing to be advantageously performed at the pack level and still be coordinated by the multipack controller.

The basic idea of the invention is to use the measuring and monitoring options provided by the individual battery packs in order to provide the multipack control unit with all the essential data for controlling the voltage equalization. The multipack control unit can then, as a higher-level control level - in particular without having to have its own sensors - the necessary parameter target values for the voltage equalization on the under orderly level of the battery packs and their battery cells.

In the case of the invention, voltage equalization or balancing of battery packs connected in series is made possible in particular. This takes into account that typically a limited communication bandwidth is available between a battery management system (BMS) of a battery pack and a multipack control unit (VIB). In order to control the balancing of the battery packs, there is usually only little information about the battery packs available. For example, the cell voltages of all individual battery cells in a battery pack cannot be transmitted; only an overall pack voltage and minimum and maximum cell voltages within a battery pack are available as battery parameters.

The invention also circumvents the limitation that there is no dedicated hardware for balancing battery packs in order to discharge individual packs in a controlled manner. Rather, the multipack control unit now controls the battery packs in such a way that they carry out the discharge or the equalization process required for balancing.

In the case of the invention, it is also avoided that balancing individual battery packs independently of one another leads to the voltage difference between the battery packs connected in parallel becoming too large and these no longer being able to be switched on. Loss of performance when starting the multipack system is therefore avoided.

In addition, unnecessarily high energy losses can be avoided when balancing an entire battery pack.

Balancing for serial battery packs in a multipack system is provided with the invention. A battery pack is discharged using the pack balancing hardware of the BMS, in particular by the pack control units. For the multipack balancing of the entire multipack arrangement, the battery cells of the individual battery packs are discharged via the pack balancing. The multipack balancing is also controlled via the multipack control unit (VIB), which activates the pack balancing in the required battery packs via a CAN bus system.

The proposed multipack balancing supports voltage and/or SOC-based balancing and ensures that the battery packs connected in parallel can be connected. By transmitting CAN commands to the battery packs, information about the desired type of balancing (SOC-based or voltage-based) and the respective parameter target value (pack voltage or pack SOC) can be transmitted. Pack balancing can continue even after the multipack controller shuts down. The multipack control unit can also receive feedback on the status and availability of pack balancing via a CAN bus system. This information and any problems that have been diagnosed can flow into the control of the multipack balancing and, if necessary, a connection strategy for the battery packs within the multipack arrangement.

Since the multipack balancing is controlled via the multipack control unit, changes to the multipack balancing parameters (in particular the parameter target value) only have to be made in one control unit and not in all pack control units. By using the pack controllers for pack balancing, no additional hardware is required.

With the system, a separate adjustment of the balancing control at the level of the multipack arrangement or at the level of the individual battery pack of pack and multipack balancing logic is possible. This allows quick adjustment to new pack types. Possible limitations caused by unbalanced battery packs, such as reduced performance if not all parallel packs can be switched on due to excessive voltage differences, are reduced by balancing at the multipack arrangement level.

Balancing can also be carried out in an energy-optimized manner for packs connected in parallel, so that as little energy as possible is lost through dissipation. In particular, the balancing is only carried out here to the extent that the connection of parallel battery packs is still possible. A further charge equalization then takes place automatically via equalizing currents when switched on in parallel.

The energy provided can be transferred to a consumer circuit in the vehicle, for example. In particular, the multipack arrangement can be connected to an electrical consumer circuit for this purpose.

A consumer circuit of the vehicle can include an electric motor drive, for example. As an alternative or in addition, the system can supply other devices in the vehicle or devices external to the vehicle with electrical energy.

A battery pack can have practically any number of parallel and/or series connected include dead battery cells. The battery pack itself is practically to be regarded as a higher-level battery cell, the parameters of which are essentially determined by the subordinate battery cells interconnected within it. A battery management system (BMS) can be used for monitoring and control.

Several battery packs can be connected in series and/or in parallel and then form a multipack system that can be monitored via a control unit, such as a "vehicle interface box" (VIB).

Typically, the problem of voltage equalization or balancing does not arise or is less urgent when battery packs are connected in parallel. In this case, compensating currents occur that can cause automatic voltage equalization.

The battery packs can also be equipped with their own BMS, which can exchange information with and be controlled by the VIB or the multipack control unit.

In particular, what is known as “pack balancing” is carried out in the system, ie a “balancing”, ie in particular a voltage equalization, for the battery cells within a battery pack. Furthermore, a “multipack balancing” can be provided, in which the battery packs are balanced within a multipack system, in particular a voltage equalization between the different battery packs.

In one embodiment of the system, the first and the second battery pack are connected in series. In general, the at least two battery packs included in the multipack arrangement can be connected in parallel or in series. Further configurations can also be provided, such as a parallel connection of a plurality of sub-units, each of which has battery packs connected in series, or a series connection of sub-units, each of which has battery packs connected in parallel.

In particular, each battery pack of the multipack arrangement is assigned its own pack control device. That is, a first pack controller is associated with the first battery pack and a second pack controller is associated with the second battery pack. The pack control devices can be integrated, for example, in the respectively assigned battery packs.

In the system, the pack control devices are set up to carry out balancing at the pack level, in particular using predetermined parameter target values. For example, target values for a cell voltage value can be specified.

A common parameter target value for the voltage equalization of all battery packs can be specified. Furthermore, different parameter target values can be specified for different battery packs, for example when they are connected to one another in a mixed parallel and series connection.

The pack control devices are also set up to record a battery parameter of the battery pack assigned to them. Such a battery parameter can be, for example, a total voltage of the pack and/or a maximum and minimum cell voltage of the individual battery cells of the battery pack. Furthermore, the detected battery parameter can relate to an operating state of the pack, for example whether voltage equalization or balancing is currently being carried out, what current is provided in the battery pack, whether the battery pack is currently being charged, whether a battery pack is currently connected or disconnected in the multipack arrangement or what state of charge the battery pack or the individual battery cells have.

In a further embodiment, the first and the second battery pack each comprise a plurality of battery cells, with the charge balancing being carried out in such a way that the parameter target value for the battery cells of the first and/or second battery pack is set. In this case, in particular, the parameter target value is also set for all battery packs comprised by the multipack arrangement.

The multipack control unit determines a parameter target value based on the battery parameter or a plurality of battery parameters which have each been recorded for a battery pack. This may be the same battery parameter read by the pack controllers, or it may be a different parameter.

The voltage equalization or balancing can therefore be understood and carried out both as equalization between the battery cells within a battery pack and between several battery packs.

In particular, during voltage equalization, the battery parameters are measured continuously or at defined intervals, and an equalization process is carried out until the target parameter value is reached. For example, a battery cell can be discharged via a resistor until the specified parameter Target value of an open circuit voltage of the battery cell is reached.

The parameter target value is determined in a manner known per se. In particular, the parameter target value can be determined in such a way that the maximum installed capacity is used. The parameter target value is designed in particular in such a way that it can be set for defined battery packs and/or battery cells in one or more battery packs. The parameter target value is in particular a target value for a parameter that can be set for the respective battery packs and/or battery cells during voltage equalization or another balancing method.

In one development of the system, the parameter target value includes a voltage value and/or a value of a state of charge (SOC) of one or more battery packs.

In particular, a distinction is made between two different balancing concepts: In the case of voltage-based balancing, the open-circuit voltage of the battery cells or battery packs is specified as the target variable. Alternatively or additionally, a specific charge state can be specified as the target value. Determining the current SOC poses an additional challenge. Typically, an SOC estimator is used for this purpose, which determines an estimated SOC value based on data on the voltage and current of the battery cell or battery pack.

The coupling between the multipack control unit and the multipack arrangement can take place, for example, by means of a data connection. The multipack arrangement can have an interface for this purpose.

The multipack control unit can also be coupled with the battery packs or the pack control devices of the battery packs, in particular in terms of data technology, for example via a common interface of the battery packs and/or the pack control devices. If necessary, the multipack control unit can be embodied as a multipack control module of a higher-level control unit or a control device.

In one embodiment, the multipack control unit does not have its own sensor device and the parameter target value is determined solely on the basis of the battery parameters received from the pack control devices.

This means that, advantageously, no separate acquisition of the battery parameters is required, but the existing possibilities of the pack control devices for acquiring relevant data are used.

In a further embodiment, the multipack control unit is coupled in terms of data technology to the multipack arrangement, in particular to the pack control units of the battery packs of the multipack arrangement, via a battery bus system, in particular via a battery CAN bus.

This advantageously uses a flexible and established form of data transmission.

In one development, the multipack control unit is coupled to the vehicle via a vehicle bus system in terms of data technology, in particular via a vehicle CAN bus.

In the system it can also be provided that the battery packs can be switched on via switch-on relay switches, with the control taking place in particular via the pack control device assigned to the respective battery pack. The battery pack associated with the pack controller can thereby be connected or disconnected within the multipack arrangement. This means that the battery packs combined in the multipack arrangement can be switched on flexibly, in particular depending on the current needs of the consumer group.

In addition, it can be provided that the pack control devices are set up to output the respective connection status, for example at regular intervals, in response to a request signal or when the connection status changes. On output, the connection status can be transmitted to the multipack controller.

Several pack control units or pack control modules can also be assigned to each of the battery packs in order to implement different functionalities; for example, controlling one or more relay switches may be executable using a first pack control module and sensing the battery parameter using a second pack control module.

In particular, the pack control devices can be set up to activate or deactivate a measurement mode in response to a control signal. When the measurement mode is activated, the respective pack control device can then record the battery parameters of the associated battery pack.

In one embodiment, the recorded battery parameter includes an open-circuit voltage or a total voltage of the battery pack, a maximum and/or minimum cell voltage within the battery pack and/or an operating state of the battery pack.

Furthermore, the detected battery parameter can relate to an operating state of the pack, for example whether a voltage equalization or a balancing process is currently being carried out, what current is provided in the battery pack, whether the battery pack is currently being charged, whether a battery pack is currently connected in the multipack arrangement or disconnected or what state of charge the battery pack or the individual battery cells have.

In one embodiment, when the voltage equalization is carried out, the battery pack is discharged via a resistor, in particular via a consumer which is connected via a consumer circuit, for example.

In particular, a "passive balancing" takes place, in which a larger charge in a battery is compensated for by reducing this charge. The energy to be released in the process is released in particular via heat. That means there is dissipative balancing with discharging the battery cells via a resistor.

In a further embodiment, active balancing takes place, in particular energy is shifted from full to empty battery cells, for example in the case of a balancing method for battery packs or battery cells connected in parallel.

Furthermore, an automatically performed balancing can be provided via compensating currents, which result in particular from voltage differences between battery packs or battery cells connected in parallel. Such compensating currents cannot be controlled or controlled directly, but arise automatically.

The voltage equalization or the balancing is therefore essentially controlled in a manner known per se.

The multipack controller can be designed in various ways to perform the balancing. In this case, in particular, a strategy for balancing and/or voltage equalization can be controlled. For example, such a strategy can relate to passive and/or active balancing of the respective battery packs or the multipack arrangement. For example, a current can be controlled that is used to balance the battery packs and/or battery cells.

In a further embodiment, the pack control devices are set up to detect the connection states of the battery packs assigned in each case and to transmit them to the multipack control unit. For example, it is determined which battery packs are currently switched on in the multipack arrangement. The voltage equalization can then be controlled depending on the connection states of the battery packs. The connection statuses can, for example, be provided by the pack control devices or can be transmitted from them to the multipack control unit.

In a further embodiment of the system, the pack control units are set up to control the respective connection state to control a connection relay switch for the associated battery pack, with the connection relay switch being closed and the associated battery pack being switched on and the connection relay switch being opened being on separate connection state of the associated battery pack is obtained within the multipack arrangement.

As a result, a particularly efficient and simple control of the battery pack is advantageously possible, in particular by means of integrated pack control devices.

In particular, the pack control devices control the connection states for a positive and a negative electrical connection of the respectively assigned battery pack, for example by means of a connection relay switch for each electrical pole. The connection relay switches can be included in the respective pack control devices and/or the associated battery packs, they can also be designed separately. A connected connection state of the associated battery pack - for at least one of the electrical poles - is obtained by closing a connection relay switch, while a disconnected connection state of the associated battery pack - for at least one of the electrical poles - is obtained by opening a connection relay switch.

In one embodiment, the multipack control unit is also set up to carry out connection management as a function of the battery parameters recorded for the battery packs and/or the parameter target value determined for the battery packs or the battery cells.

In this case, for example, those battery packs that are to be discharged as part of the charge equalization can be preferentially switched on. Furthermore, battery packs can be switched on with less preference if charge equalization is currently being carried out on them or if charge equalization is necessary, in particular if there is a large voltage difference to other battery packs.

In one embodiment, the multipack control unit is set up to receive a request signal and to control at least one pack control device as a function of the request signal in such a way that the connection state of the respectively assigned battery pack is changed. In this case, in particular, the control takes place as a function of a battery parameter received for the assigned battery pack or an insulation state of the battery pack.

As a result, an activation strategy for the battery packs in the multipack arrangement can advantageously be achieved in such a way that selective connection or disconnection of specific battery packs is also controlled from the aspect of balancing for the battery packs or the battery cells of the battery packs.

In the method for operating a system for providing energy for a vehicle, the system comprises a multipack arrangement with at least a first battery pack and a second battery pack and a multipack control unit coupled to the multipack arrangement. A pack control unit is assigned to the first and the second battery pack. A battery parameter of the respectively assigned battery pack is recorded, a parameter target value is determined using the received battery parameters, and charge equalization for the respectively assigned battery pack is carried out using the received parameter target value.

The method is designed in particular to operate the system. It therefore has the same advantages as the system according to the invention.

• 1 ein Ausführungsbeispiel des Systems für in Serie geschaltete Batteriepacks in einer Multipack-Anordnung;
• 2 ein weiteres Ausführungsbeispiel des Systems.

The invention is explained in more detail below with reference to the attached drawings. show it

• 1 an embodiment of the system for series-connected battery packs in a multi-pack arrangement;
• 2 another embodiment of the system.

In reference to 1 an embodiment of the system for battery packs connected in series in a multi-pack arrangement is explained.

The system includes a multipack assembly 20.

In the example, the multipack arrangement 20 comprises three battery packs 22, 24, 26.

At the in the 1A until 1C example shown, the battery packs 22, 24, 26 are connected in series.

In a further exemplary embodiment, which is not shown, the battery packs are connected in parallel. Furthermore, mixed configurations can be provided, such as a parallel connection of a plurality of sub-units, each having battery packs connected in series, or a series connection of sub-units, each having battery packs connected in parallel.

The multi-pack arrangement 20 is electrically connected to a load circuit 10 of a vehicle 11 , the multi-pack arrangement 20 also being comprised by the vehicle 11 in the example. The consumer circuit includes in particular an electric drive of the vehicle 11.

The electrical connection between the multipack arrangement 20 and the consumer circuit 10 is made via a high-voltage (HV) connection. In the example, the HV connection includes a negative pole HV- and a positive pole HV+.

A switch (not shown) can be provided for switching the connection between the multipack arrangement and the load circuit 10, in particular with a switch each for the poles HV-, HV+ of the HV connection.

The battery packs 22, 24, 26 each comprise a multiplicity of individual battery cells (not shown), which are connected to one another in series and/or in parallel within the battery pack 22, 24, 26.

Furthermore, in the exemplary embodiment, each of the battery packs 22, 24, 26 can have two connection relay switches (not shown), namely a first connection relay switch for closing or opening an electrical connection at the negative pole of the battery pack 22 and a second connection relay switch for Closing or opening an electrical connection on the positive pole of the battery pack 22.

That is, each individual battery pack 22, 24, 26 can have its electrical connections independently opened or closed by the associated staging relay switch to connect or disconnect the respective battery pack 22, 24, 26 within the multi-pack assembly 20.

At the in 1 In the case shown, all connection relay switches are closed and the battery packs 22, 24, 26 are thereby connected to one another in series and connected to the load circuit 10.

Each battery pack 22, 24, 26 has a pack controller 23, 25, 27 assigned to it.

In the example, the pack control devices 23, 25, 27 are integrated into the respective associated battery packs 22, 24, 26; in further exemplary embodiments, they can also be designed separately from them.

The pack control devices 23, 25, 27 are set up to control the respective switching states of the connection relay switches of the associated battery packs 22, 24, 26 and thereby correspondingly control the connection state of the battery packs 22, 24, 26 within the multipack arrangement 20.

In the example, the connection state of a battery pack 22, 24, 26 is defined by the switch positions of the connection relay switches.

In particular, a (completely) disconnected connection state of a battery pack 22, 24, 26 can be defined, in which the connection relay switches are open and the electrical connections to the negative HV and positive HV+ pole of the connection of the multipack arrangement 20 are interrupted.

Furthermore, in particular a (completely) connected connection state of a battery pack 22, 24, 26 can be defined, in which the connection relay switches are closed and the electrical connections to the negative HV and positive HV+ pole of the connection of the multipack arrangement 20 are closed.

In addition, mixed states can be provided in which one of the connection relay switches of a battery pack 22, 24, 26 is open and the other is closed.

The pack control devices 23, 25, 27 are accordingly set up to open or close the connection relay switches of the associated battery packs 22, 24, 26.

In further exemplary embodiments, the pack control devices 23, 25, 27 can also be set up to detect an insulation state of the respectively associated battery pack 22, 24, 26. For this purpose, a measuring circuit can be provided which is designed in a manner known per se, in particular in accordance with standards, and is set up to measure an insulation resistance between the associated battery pack 22 , 24 , 26 and a chassis of the vehicle 11 . In particular, two resistance values are measured, namely between the negative pole of the battery pack 22, 24, 26, approximately in the area of the connection relay switch for the negative pole, and the vehicle chassis and between the positive pole of the battery pack 22, 24, 26, approximately in Area of the positive pole energizing relay switch, and the vehicle chassis.

The system also includes a multipack controller 30.

In the example, the multipack control unit 30 is connected via a battery CAN bus 31 to the multipack arrangement 20 and/or to the individual battery packs 22, 24, 26 of the multipack arrangement 20 and/or to the control units 23, 25, 27 of the battery packs 22, 24, 26 coupled in terms of data technology.

Furthermore, in the example, multipack control unit 30 is coupled via a vehicle CAN bus 32 to consumer circuit 10 or another unit of vehicle 11, in particular to a vehicle control unit (not shown).

In the following we use the in 1 shown and explained above embodiment of the system an embodiment of the method is explained.

The pack control devices 23, 25, 27 record a battery parameter of the respectively assigned battery pack 22, 24, 26.

In the exemplary embodiment, the pack control units 23, 25, 27 each record the no-load voltage or the total voltage of the associated battery pack 22, 24, 26 and the minimum and maximum cell voltage of the battery cells comprised by the associated battery pack 22, 24, 26. In addition, in the embodiment, an operating state of the associated battery pack 22, 24, 26 is detected, in particular relating to a state of charge, a connection state and information about whether the battery pack 22, 24, 26 is currently being charged or whether a Discharge or a provision of electrical energy for a consumer takes place.

The detected battery parameters are transmitted to the multipack control unit 30 via the battery bus system 31 .

The multipack control unit 30 uses the received battery parameters of the connected battery packs 22, 24, 26 to determine a parameter target value for the battery packs 22, 24, 26. In the exemplary embodiment, this parameter target value includes a target voltage value.

The target parameter value or the target voltage value is transmitted to the battery packs 22, 24, 26 and voltage equalization is carried out on them. The battery cells included in the battery packs 22, 24, 26 are brought to approximately the same voltage value, which is determined using the target voltage value for the respective battery pack 22, 24, 26.

In the case of the voltage equalization, a dissipative balancing takes place in the example, that is to say battery packs 22, 24, 26 or battery cells are discharged in such a way that they are brought to the desired target voltage value. The excess electrical energy is given off in particular as heat. This is in particular a "passive" balancing.

In a further exemplary embodiment, “active” balancing can alternatively or additionally be carried out, in which case electrical energy from certain battery packs 22, 24, 26 or battery cells is taken up by other battery packs 22, 24, 26 or battery cells in order to balance the voltage and achieve an even level to reach.

The exemplary embodiment described here relates to balancing, in which the cell voltages of the battery packs 22, 24, 26 and the battery cells contained therein are assumed. In this case, a target voltage is specified as the target parameter value.

In another embodiment, the control may be based on a state of charge (SOC). In this case, an SOC is recorded as a battery parameter, with the pack control devices 23, 25, 27 in particular carrying out an SOC estimate using measured current and voltage values. A target SOC value is then determined on the basis of these SOC estimates for the individual battery packs 22 , 24 , 26 and transmitted to the pack control devices 23 , 25 , 27 . These control a balancing process in order to obtain the target SOC value in the battery packs 22, 24, 26 or the battery cells they contain.

A further exemplary embodiment also provides for the multipack control unit 30 to receive a request signal. The request signal is transmitted, for example, via the vehicle bus system 32.

The request signal can be generated, for example, by a vehicle control unit and formed as a function of a power requirement from consumer circuit 10 and the devices included therein. For example, the request signal is formed in such a way that an increase in the power provided by the multipack arrangement is achieved.

Furthermore, a request signal can be formed in order to put the vehicle into operation and to switch on the battery packs 22, 24, 26 in the multipack arrangement 20. Conversely, a request signal can be formed to disconnect the battery packs 22, 24, 26 of the multipack arrangement by opening the connection relay switch. That is, connection management is performed.

Depending on the request signal received, the multipack control unit 30 controls the pack control devices 23, 25, 27 in such a way that the connection relay switches of the respectively assigned battery packs 22, 24, 26 are kept in the current state, opened or closed.

Provision can be made here for the multipack control unit 30 to determine a connection strategy on the basis of the previously received connection states, battery parameters and/or insulation states of the battery packs 22, 24, 26. The connection strategy includes in particular data on the total number of connected battery packs 22, 24, 26 and on the selection of connected or disconnected battery packs 22, 24, 26. In particular, a preference can be determined for individual battery packs 22, 24, 26 as to which battery packs 22, 24 , 26 are preferably connected or disconnected.

In the exemplary embodiment, this connection strategy can be generated as a function of the battery parameters and/or insulation states detected for the battery packs 22, 24, 26, for example in order to avoid connecting faulty battery packs 22, 24, 26.

In reference to 2 a further exemplary embodiment of the system is explained. This essentially corresponds to that referred to above to 1 explained first embodiment. Comparable elements are therefore provided with the same reference symbols and will not be explained again in detail.

This in 2 The system shown differs from that in 1 shown embodiment characterized in that the multipack control unit 30 is designed as an interface between the vehicle 11 and the multipack assembly 20. In particular, it is a vehicle interface box (VIB). This can have connections, for example, via which the multipack arrangement 20 can be electrically connected to the load circuit 10 .

The other elements and the technical data connections 31, 32 to the multipack control unit 30 correspond to the configuration explained above.

In another embodiment, the multipack controller 30 is comprised of a VIB.

Reference List

10

Electrical consumer circuit

11

vehicle

20

Multipack arrangement

22, 24, 26

battery pack

23, 25, 27

Pack control units

30

Multipack control unit

31

CAN bus (battery CAN bus)

32

CAN bus (vehicle CAN bus)

HV+

connection (positive pole)

HV

connection (negative pole)

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US 2016/0297318 A1 [0005]
• DE 102019132640 A1 [0006]
• DE 102018004891 A1 [0007]
• DE 102018131450 A1 [0008]

Claims (10)

System for providing energy for a vehicle (11); full a multipack arrangement (20) having at least a first battery pack (22) and a second battery pack (24, 26); and a multipack controller (30) coupled to the multipack assembly (20); whereby a pack control unit (23, 25, 27) is assigned to each of the first (22) and the second battery pack (24, 26); whereby the pack control devices (23, 25, 27) are set up to detect a battery parameter of the respectively assigned battery pack (22, 24, 26); whereby the multipack control unit (30) is set up to receive the battery parameters of the respectively assigned battery packs (22, 24, 26) detected by the pack control devices (23, 25, 27) and to determine a parameter target value based on the received battery parameters and transmit to at least one of the battery packs (22, 24, 26); whereby the pack control devices (23, 25, 27) are also set up to use the received parameter target value to carry out voltage equalization for the battery pack (22, 24, 26) assigned in each case. Device according to claim 1 , characterized in that the first (22) and the second battery pack (24, 26) are connected in series. Device according to one of the preceding claims, characterized in that the first (22) and the second battery pack (24, 26) each comprise a plurality of battery cells; wherein the charge balancing is performed such that the parameter target value for the battery cells of the first (22) and/or second battery pack (24, 26) is adjusted; In particular, the parameter target value for all of the battery packs (22, 24, 26) included in the multipack arrangement (20) is also set. Device according to one of the preceding claims, characterized in that the parameter target value comprises a voltage value and/or a value of a state of charge (SOC) of one or more battery packs (22, 24, 26). Device according to one of the preceding claims, characterized in that the multipack control unit (3) does not have its own sensor device and the parameter target value is determined exclusively on the basis of the battery parameters received from the pack control units (23, 25, 27). Device according to one of the preceding claims, characterized in that the multipack control unit (30) communicates with the multipack arrangement (20) in terms of data technology via a battery bus system (31), in particular via a battery CAN bus (31). is coupled, in particular with the pack control devices (23, 25, 27) of the battery packs (22, 24, 26) of the multipack arrangement (20). Device according to one of the preceding claims, characterized in that the multipack control unit (20) is coupled in terms of data technology to the vehicle via a vehicle bus system (32), in particular via a vehicle CAN bus (32). Device according to one of the preceding claims, characterized in that the detected battery parameter is a total voltage of the battery pack (22, 24, 26), a maximum and/or minimum cell voltage within the battery pack (22, 24, 26) and/or an operating state of the battery pack (22, 24, 26). Device according to one of the preceding claims, characterized in that when the voltage equalization is carried out, the battery pack (22, 24, 26) is discharged via a resistor. Method for operating a system for providing energy for a vehicle (11); where the system includes: a multipack arrangement (20) having at least a first battery pack (22) and a second battery pack (24, 26); and a multipack controller (30) coupled to the multipack assembly (20); whereby a pack control unit (23, 25, 27) is assigned to each of the first (22) and the second battery pack (24, 26); whereby a battery parameter of the respectively associated battery pack (22, 24, 26) is detected; a parameter target value is determined based on the received battery parameters; and a charge equalization for the battery pack (22, 24, 26) assigned in each case is carried out on the basis of the parameter target value received.

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