Individual open- / closed-loop control of battery modules

Abstract

The present invention relates to a method for the open- / closed-loop control of a battery module of an electric vehicle and to a corresponding battery system having a plurality of battery modules. A method for the open- / closed-loop control of a battery module (12) in a battery system (10) of an electric vehicle having a plurality of battery modules (12) is correspondingly proposed, comprising the steps of: capturing battery module data (20) in each battery module (12); transmitting the battery module data (20) from a respective battery module (12) to every other battery module (12); and determining, in each battery module (12) by means of an electronic control unit of the respective battery module (12), a measure to be carried out by the respective battery module (12) on the basis of the received battery module data (20) and the battery module data (20) captured by the respective battery module (12). The logic is identical for each electronic control unit and the measure is determined independently of a master battery module (12a; 12b) of the battery modules (12).

Description

[0001] Individual control / regulation of battery modules

[0002] Technical area

[0003] The present invention relates to a method for controlling / regulating a battery module of an electric vehicle and a corresponding battery system with several battery modules.

[0004] State of the art

[0005] Battery modules in electric vehicles are typically used as a battery system with multiple battery modules or, alternatively, as a single battery pack. However, if multiple battery modules are provided, they are usually monitored and coordinated by a higher-level battery management system. This ensures that, for example, various functions, charge levels, and switching states of the battery modules can be controlled or regulated according to a defined protocol.

[0006] However, the provision of a central battery management system has the disadvantage that an additional control device must be provided in a separate housing and with mechanical protection devices, making manufacturing more labor-intensive and costly. Furthermore, such a central battery management system requires a relatively high level of logic complexity at the software level to ensure safe and sufficient coordination of the individual battery modules. Furthermore, in the event of a defect in the higher-level battery management system, the entire battery system is shut down or no longer available, making the energy supply required for the electric vehicle error-prone.

[0007] Accordingly, there is a need to provide a more efficient battery system with simplified and reliable control of the battery modules. Description of the invention

[0008] Based on the known prior art, it is an object of the present invention to provide an improved method for controlling / regulating the battery modules and a corresponding battery system.

[0009] The object is achieved by a method for controlling / regulating a battery module having the features of claim 1. Advantageous further developments emerge from the subclaims, the description, and the figures.

[0010] Accordingly, a method for controlling / regulating a battery module in a battery system of an electric vehicle with several battery modules is proposed, comprising the steps:

[0011] Collecting battery module data in each battery module;

[0012] Transferring the battery module data from a respective battery module to each other battery module; and

[0013] Determining, in each battery module by means of an electronic control unit of the respective battery module, an action to be carried out by the respective battery module based on the received battery module data and the battery module data acquired by the respective battery module, wherein a logic is identical for each electronic control unit and wherein the determination of the action takes place independently of a master battery module of the battery modules.

[0014] The determination of the measure can thus be carried out in parallel in each battery module and independently of the other battery modules, whereby each battery module has the same information for this purpose, since the battery module data of all battery modules are transferred to each other.

[0015] Because each battery module or electronic control unit has the same logic, a coordinated sequence of measures can be carried out without the need for additional control or regulation by a master battery module. In other words, the battery modules can function virtually autonomously or control / regulate themselves. The logic can represent a type of rule set that is deterministic and, in particular, generates defined and reproducible outputs based on predetermined inputs and / or parameters, such as the battery module data. This determinism means that each battery module inevitably reaches a decision based on the battery module data that the other battery modules also reach. This is because both the logic and the available or received battery module data are identical for each electronic control unit.This prevents divergence in the decisions of the battery modules.

[0016] The logic can, for example, be present at a software level, for example in the form of software or program code that is loaded and processed in a processor, but can also be provided as a pre-programmed sequence program in a microprocessor or as a (digital) ASIC or as a system-on-a-chip.

[0017] Accordingly, a battery management system can be advantageously dispensed with, or such an additional component can be eliminated. This can significantly reduce the cost of the battery system and simplify its manufacture and implementation. Furthermore, the elimination of a battery management system can ensure continuous performance of the battery system, especially since higher-level control defects are effectively avoided due to the determination of the measure in the individual battery modules.

[0018] Accordingly, the action can only be determined in the respective battery module. In addition to the battery module data, other data such as vehicle-side instructions or queries may be taken into account. However, the action is determined neither by a master battery module nor by a central battery management system.

[0019] Because each battery module has the same logic for determining the action, the battery modules can also be designed differently. Preferably, however, each battery module is designed identically. This allows the battery modules to be arranged in any order, and greater uniformity of the transmitted battery module data is achieved or expected during normal operation. For example, differences in the state of charge or voltage range of the battery modules can be minimized, which also simplifies the logic and allows the action to be determined with greater accuracy.In order to provide secure communication between the battery modules that is essentially independent of the vehicle-side electronics, it is preferably provided that the battery module data is transmitted to each battery module via a battery CAN bus that is separate from the control device of the electric vehicle. Such a battery CAN bus can thus be provided before or parallel to the insertion of the battery module into the electric vehicle and connected to the respective battery modules and is independent of a vehicle CAN bus. In other words, communication between the battery modules preferably takes place exclusively via the battery CAN bus, although the respective battery modules can also be communicatively connected to the vehicle CAN bus.

[0020] The battery CAN bus thus ensures that the battery module data can be reliably transmitted and received, while simultaneously preventing communication errors from occurring on a vehicle CAN bus. Determining the appropriate action can thus be supported by ensuring that each battery module has the same battery module data via the battery CAN bus.

[0021] The measure can correspond to a function or predefined response of the respective battery module. Preferably, the measure is a change in the switching state, in particular, connecting the respective battery module. This is because connecting the battery modules typically requires a coordinated response from all battery modules to ensure safe commissioning of the battery system. Thanks to the existing battery module data and the logic in the respective control unit, which are identical for each battery module, the individual battery modules can thus ensure safe connection without the need for a higher-level control / regulation in the sense of a battery management system.

[0022] The battery module data can include the switching state of the respective battery modules, whereby the battery modules connect upon receiving a connection command from a control device of the electric vehicle based on a predetermined sequence of the battery modules and the received switching states. The battery modules can transmit their current switching state to the other battery modules using the battery module data, optionally with additional battery module data, so that each battery module can determine whether it is its turn to connect based on the received switching states and the predetermined sequence. As soon as the next battery module is connected, it changes its switching state accordingly in the transmitted battery module data so that the next but one battery module can connect.

[0023] The order of the battery modules can be specified based on a prioritization defined in the logic. For example, the order of the battery modules can be determined based on a predefined wiring or so-called "pinning" or based on a predefined numbering. However, the battery module data preferably includes voltage data of the respective battery modules in a non-connected state, with the order of the battery modules in each battery module being determined starting from the battery module with the highest voltage and in descending order of voltage.

[0024] Accordingly, the battery module with the highest measured voltage can be the first to connect, and the battery module with the lowest measured voltage can be the last to connect. Because all battery modules receive the respective voltage data, each battery module can determine its own position in the sequence. The sequence is the same for each battery module due to the identical voltage data and the same logic. In other words, all battery modules come to the same conclusions, so that the battery modules are connected in an order determined jointly by all battery modules.

[0025] It can also be provided that the battery module data include voltage data of the respective battery modules in a non-connected state, with the respective battery module only connecting when it determines that its measured voltage is within a specified voltage range. This can prevent battery modules from being connected with too low a voltage, for example, due to reduced charging capacity, which could lead to performance fluctuations or prevent a specified target voltage from being reached or maintained.

[0026] The maximum value of the voltage range can be specified by the battery module with the highest voltage, and the minimum value of the voltage range can be specified by the maximum value reduced by a specified voltage value or specified percentage. For example, at a maximum value of approximately 855 V, the minimum value can be defined by a reduced absolute voltage between 5 V and 15 V, for example approximately 10 V, so that battery modules with a voltage in the voltage range between 845 V and 855 V can be connected. Likewise, battery modules with a voltage below 845 V, for example 830 V, are not connected in such a case. In addition to or alternatively to the absolute value, it can also be provided that the minimum value of the voltage range is formed by reducing the maximum value by a specified percentage.For example, with a maximum value of approximately 855 V, a percentage deviation of between 0.5 percent and 2 percent can form the corresponding tolerance range.

[0027] To enable reliable and collision-free communication between the battery system and the vehicle-side system, it can further be provided that only the master battery module transmits battery module data to a control device of the electric vehicle. In general, the master battery module can be understood as a CAN communication master or as a vehicle CAN bus speaker battery module, so that the master battery module represents a so-called required "speaker" for the vehicle CAN bus within the meaning of the CAN specification. The master battery module therefore does not provide control for slave battery modules. In other words, the master battery module can be provided exclusively as a bus master.The master battery module receives all battery module data, just like all other battery modules, but is the only battery module configured to transmit battery module data to the electric vehicle's control unit. This allows compliance with communication protocols and also prevents multiple battery modules from transmitting battery module data to the control unit at the same time.

[0028] In particular, it can be provided that each battery module receives data from a control device of the electric vehicle via a vehicle CAN bus, and that the master battery module transmits the battery module data to the control device via the vehicle CAN bus. In this way, bus-compliant communication can be provided, wherein only the master battery module transmits the battery module data to the control device of the electric vehicle via the vehicle CAN bus, but all battery modules can receive system-relevant or vehicle-relevant data from the control device of the electric vehicle. Accordingly, the battery modules can all be communicatively connected to the vehicle CAN bus and also be suitable for transmission to the vehicle CAN bus. However, the transmission function is only enabled or activated for the master battery module.

[0029] Alternatively, it can also be provided that only the master battery module receives data from a control device of the electric vehicle via the vehicle CAN bus or only certain data from the control device, for example alarm and / or emergency data, are received by the master battery module while other data, for example for regular operation and / or for switching the respective battery modules, can be received by all battery modules via the vehicle CAN bus.

[0030] The battery module data transmitted to the control device can include or consist of consolidated battery module data. Each battery module can also consolidate the received battery module data and the acquired battery module data. Consolidating the battery module data can be advantageous for on-board utilization, for example, to monitor and / or specify the charge states of the battery modules.

[0031] In this sense, "consolidation" means, for example, summarizing, compiling, and / or processing the battery module data by the master battery module so that protocol-compliant bus communication with the control unit of the electric vehicle can be ensured. In other words, the master battery module can thus assume a bus master function, which may be necessary for communication via a CAN bus. However, consolidation does not constitute decision derivation, especially since decisions for each battery module are made based on its own internal logic.

[0032] Furthermore, consolidation avoids redundancy and provides more efficient data transmission. Because each battery module has the same battery module data, the consolidated battery module data in each battery module is identical. This has the advantage that in the event of a master battery module failure, another battery module can simply take over the function of the master battery module and subsequently transmit the consolidated battery module data to the control device without requiring an alternative configuration of the downstream battery module.

[0033] In order to determine which battery module should act as a master battery module and, for example, transmit battery module data to the vehicle-side control device, it can be provided that in each battery module, by means of the electronic control unit of the respective battery module and based on the received battery module data and battery module data acquired by the respective battery module, it is determined whether the respective battery module should assume the function of a master battery module.

[0034] For example, the battery module data can include still-alive messages. If a still-alive message is missing from a battery module currently designated as the master battery module, each battery module redetermines whether it should assume the function of the master battery module. For example, the logic can be used to specify that a battery module with the highest voltage assumes the function of the master battery module. Because the corresponding battery module data is available to each battery module, it is clear for each battery module which battery module is to be considered the master battery module and whether, for example, the respective battery module should transmit data via a vehicle CAN bus or not.

[0035] The master battery module can also be determined based on a prioritization defined in the logic. For example, an initial master battery module can be defined based on a so-called "pinning" process. In the event of a failure of the battery module previously operated as the master battery module, one of the remaining battery modules is connected downstream as the master battery module. This connection, which can occur instantaneously and during operation, is determined based on a predefined prioritization defined in the logic and a numbering of the battery modules.If there is no corresponding still-alive message from the previous master battery module, for example because this still-alive message is not sent in the event of a failure, the battery module with the corresponding number can be connected downstream as the master battery module based on the prioritization or the specified sequence and with regard to the battery module number contained in the battery module data and take over the corresponding function.

[0036] The battery module data preferably includes state of charge (SOC) data, state of health (SOH) data, state of function (SOF) data, and / or voltage data of the battery modules. In this way, relevant data can be provided, for example, in the form of consolidated battery module data for a vehicle-mounted control device. Likewise, for example, based on the state of charge and / or voltage data of the battery modules, as described above, connecting the battery modules can be supported, in that the battery modules perform this virtually autonomously in a predetermined sequence.

[0037] Transmitting battery module data to all battery modules also has the advantage that all battery modules can be informed about the current status of the respective battery modules. This means that the battery module data for a particular battery module can also contain an error message if an error is detected by that battery module. This has the advantage that the error message can be taken into account in the internal decision-making process for each individual battery module and / or the error message can be logged accordingly.

[0038] In this way, the error message can be used for balancing and / or to determine the total capacity.

[0039] In the event of a local fault, the affected battery module can open its closed HV contactor, and in the event of a systemic fault, all battery modules can open their closed HV contactors based on the error message. This prevents any further damage to the respective battery modules and ensures the safe use of the battery system. This also allows the error message to be recorded, for example, in consolidated battery module data and transmitted via the master battery module to a vehicle-side control device, allowing appropriate safety measures or checks to be carried out.

[0040] Furthermore, it can be provided that, in the event of a systemic fault on the vehicle, the battery modules receive a systemic error message from a control device of the electric vehicle via a vehicle CAN bus and, in response, activate their emergency shutdown. The emergency shutdown can include predefined emergency measures that lead to an emergency shutdown of the battery system and fundamentally differ from an orderly shutdown of the battery in the normal state.

[0041] For example, in the event of a vehicle collision, a corresponding signal can be transmitted via the vehicle CAN bus, whereupon the battery modules fire a pyroelectric element or a so-called "pyro-fuse," thus almost immediately separating or isolating the battery modules from the HV line to the vehicle. In this respect, too, the communicative connection of the battery modules to the vehicle CAN bus is advantageous, especially since corresponding data and signals can be received without difficulty. However, bus-compliant transmission to the control device is preferably carried out exclusively by the master battery module.

[0042] In order to be able to subsequently check and / or eliminate an existing error, it is preferably provided that, in the case of a local error, the respective battery module logs the error in an error memory of the respective battery module and / or, in the case of a systemic error, all battery modules log the error in a respective error memory. One advantage of such local storage of an error message is that the error can be reported immediately to a vehicle-side control device when it occurs, but this device can also be read out at a later time, for example during a non-critical, maintenance-related check, in order to, for example, investigate the cause of the error and replace the specific battery module.Storing a systemic error in all error memories of the battery modules, on the other hand, ensures that safety redundancy is provided in the event of a collision or crash, for example, so that the error can be read out even if the battery system is significantly damaged.

[0043] The above-mentioned object is further achieved by a battery system for an electric vehicle having the features of claim 22. Advantageous developments of the battery system emerge from the subclaims as well as the present description and the figures.

[0044] Accordingly, a battery system for an electric vehicle is proposed, comprising at least two battery modules, each battery module having its own electronic control unit. Each battery module is configured to acquire battery module data from the respective battery module and transmit this data to every other battery module. Furthermore, the logic for each electronic control unit is identical, and each electronic control unit is configured to determine an action to be performed by the respective battery module based on the received battery module data and the battery module data acquired by the respective battery module, independently of a master battery module of the battery modules.

[0045] Each battery module can comprise a plurality of battery cells arranged in a housing of the battery module, which together determine the power of the battery module. Connected in series, alternatively connected in parallel, or in a mixed form, with some modules connected as a parallel module bank and several modules connected in series, particularly via respective HV contactors, the battery modules accordingly form the battery system for an electric vehicle.

[0046] Preferably, the battery modules are communicatively connected to one another via a battery CAN bus for transmitting the battery module data. As described above, such a battery CAN bus has the advantage that the battery modules can reliably transmit battery module data to one another without causing a collision with a vehicle CAN bus. Furthermore, this ensures that each battery module has the same battery module data via the dedicated communication path.

[0047] Likewise, each of the battery modules can be connected to a vehicle CAN bus for receiving data from a control device of the electric vehicle, wherein preferably only one master battery module of the battery modules is configured to transmit battery module data to the control device via the vehicle CAN bus. Thus, bus-compliant communication with the vehicle-side system can be ensured without the need for a separate battery management system.

[0048] Preferably, the battery system is configured to carry out the above-described method according to the invention. The features described with regard to the method and the associated technical advantages apply accordingly to the battery system, so a repeated description of these method-related features and technical advantages is omitted to avoid redundancies.

[0049] Short description of the characters

[0050] Preferred further embodiments of the invention are explained in more detail in the following description of the figures. In the figures:

[0051] Figure 1 shows a schematic representation of a battery system according to the invention, wherein the respective battery modules are connected;

[0052] Figure 2 shows a schematic representation of the battery system according to the invention, wherein in the connected state an alternative battery module is determined as the master battery module;

[0053] Figure 3 shows a schematic representation of the battery system according to the invention when a fault is detected in a battery module;

[0054] Figure 4 shows a schematic representation of the battery system according to the invention in the event of a vehicle-side fault; and

[0055] Figures 5 and 6 show preferred block diagrams for a sequence of the internal logic or a partial logic for various functions of the battery modules.

[0056] Detailed Description of Preferred Embodiments Preferred embodiments are described below with reference to the figures. Identical, similar, or equivalent elements in the different figures are provided with identical reference numerals, and a repeated description of these elements is partially omitted to avoid redundancies.

[0057] Figure 1 schematically illustrates a battery system 10 according to the invention, which comprises a plurality of battery modules 12, in this case a non-limiting number of five. The battery modules 12 are communicatively connected to one another via a battery CAN bus 14, so that the battery modules 12 can transmit data to and receive data from one another, as indicated by the double arrows. The battery CAN bus 14 is configured exclusively for communication between the battery modules 12 and thus forms an independent component of the battery system 10.

[0058] A control device 16 is also provided on the vehicle side. The control device 16 can be designed, for example, as a vehicle control unit, also known as a VCU ("vehicle control unit"), which is configured, for example, to coordinate the connection of the battery modules 12 and to specify the target voltage to be adjusted. Accordingly, in addition to the battery CAN bus 14, a vehicle CAN bus 18 is provided, which is also communicatively connected to the respective battery modules 12. However, the battery CAN bus 14 is independent of the vehicle CAN bus 18. Accordingly, battery module data 20, which is acquired or provided by the respective battery modules 12, can be transmitted between the battery modules 12 via the battery CAN bus 14, so that each battery module 12 has both its own battery module data 20 and the battery module data 20 of all other battery modules 12.

[0059] To enable bus-compliant communication between the battery system 10 and the control device 16, it is further provided that one battery module 12 has been designated as the master battery module 12a, and only the master battery module 12a is configured to transmit battery module data 20 to the control device 16 via the vehicle CAN bus 18. In the present example, the battery module data 20 of all battery modules 12 are consolidated in the master battery module 12a, so that the master battery module 12a transmits consolidated battery module data 22 to the control device 16, as shown by the corresponding double arrow. However, each battery module 12 is configured to receive data from the control device 16 via the vehicle CAN bus 18, as shown by the individual arrows. In the present example, a connection command 24 was transmitted by the control device 16 and received by the respective battery modules 12.An electronic control unit is provided in each battery module 12 for determining measures to be carried out, such as connection, wherein the logic is identical for each electronic control unit. Accordingly, based on the connection command 24, the logic in each battery module 12 determines whether the respective battery module 12 should be connected. For this purpose, the battery module data 20 includes both the voltage of the respective battery module 12 and the switching state of the respective battery module 12. Based on the voltage, an order of connection for the battery modules 12 can preferably be determined, wherein the battery module 12 with the highest voltage should be connected first and the battery module 12 with the lowest voltage last.

[0060] Because the switching states of all battery modules 12 are available to each battery module 12 and each battery module 12 has the same logic, the same sequence is determined in each battery module 12 based on the received battery module data 20. Thus, a predetermined sequence of connection can be initiated and maintained by each battery module 12 without the need for a battery management system or control by the master battery module.

[0061] Furthermore, it can be determined or checked in each battery module 12 whether the respective battery module 12 should actually be connected. Based on the received voltage data and the battery module's own voltage, it can be determined whether the battery module's own voltage deviates from a specified voltage range, and connection can be prevented in the event of such a deviation. In this way, for example, performance fluctuations can be largely avoided.

[0062] However, if the voltage is within the tolerance range, the respective battery module 12 can be connected according to the sequence. However, to prevent connection from leading to a potential hazard, it can also be provided that the respective battery module 12 checks whether a local or systemic fault exists, whereby the battery modules 12 are only connected if there is no local fault for the respective battery module 12 or no systemic fault for the battery modules as a whole.

[0063] Figure 2 schematically shows how, when the battery modules 12 are connected, an alternative battery module 12 is designated as the master battery module 12b. In the present case, an error or communication error has occurred in the initial master battery module 12a. This is detected by the other battery modules 12 in that a corresponding still-alive message as part of the battery module data 20 is no longer sent by the master battery module 12a and, accordingly, is not received by the other battery modules 12. Accordingly, it is then determined in each other battery module 12 whether it can assume the function of a master battery module. In this case, this is done based on a predetermined order established in the logic or by pinning. Accordingly, the battery module 12 with the highest priority was designated as the master battery module 12b.Because the logic is identical for each battery module 12 and each battery module 12 has the same battery module data 20, the same master battery module 12b is determined in each battery module 12. The master battery module 12b is now configured to transmit the consolidated battery module data 22 to the control device.

[0064] Figures 3 and 4 schematically illustrate two different situations in which an error has been detected. In Figure 3, an error was detected in a battery module 12, and a corresponding error message 26 was transmitted to the other battery modules 12 via the battery CAN bus 14. The error can be a local error, for example, a detected temperature of the battery module 12 that exceeds a threshold value or an HV contactor of the battery module 12 that is stuck in the open state. In such cases, it can be provided that the HV contactor of the corresponding battery module 12 is opened, if this has not already occurred, and an error message 26 is transmitted in the battery module data 20 so that it can be transmitted from the master battery module 12a to the control device 16 for signaling to the user of the electric vehicle.The error message 26 is also logged in the error memory of the relevant battery module 12.

[0065] However, if a systemic error is detected, error message 26 causes each battery module 12 to open its HV contactor and log error message 26 in the respective error memory. Such a systemic error can occur, for example, if it is detected that an interlock error is present and an HV connector is not contacted as intended. This can, for example, lead to an open circuit in a conductor loop between all HV connectors connected in series. However, error message 26 transmitted via the battery CAN bus 14 can effectively prevent a safety-critical condition, especially since all battery modules open their HV contactors. The reverse, vehicle-side case of a systemic error is shown schematically in Figure 4. In this example, an error is detected by the control device 16, for example a collision or a crash.The error message 26 is transmitted directly to the respective battery modules 12 via the vehicle CAN bus 18. Each battery module 12 receives the error message 26 and subsequently activates its emergency shutdown. This allows each battery module 12 to fire a pyroelectric element, so that the respective battery module 12 is disconnected or isolated from the battery system 10 almost immediately.

[0066] The advantageous combination of the battery CAN bus 14 and the vehicle CAN bus 18 ensures that function-relevant and safety-relevant information can be transmitted reliably. Furthermore, the battery CAN bus 14, which is separate from the vehicle CAN bus 18, ensures that the battery modules 12 always have the same battery module data 20. This allows the actions to be executed to be determined based on the identical logic present in each battery module 12, and communication with the vehicle-side control device can be ensured without requiring control from the master battery module or a battery management system.

[0067] Figures 5 to 6 schematically illustrate preferred block diagrams for a sequence of the internal logic or a partial logic for various functions of the battery modules. Since all sequence steps have already been explained above, the various preferred sequence steps will only be briefly discussed to illustrate the interaction of the various functions and optional implementations for a corresponding logic algorithm.

[0068] Accordingly, Figures 5A to 5D show a block diagram or an algorithm that enables the battery modules to be successively connected based on the internal logic of the battery modules. Thus, in step S1, each battery module n first transmits its voltage and its switching state with respect to an HV string in the form of battery module data, preferably via a battery CAN bus. This battery module data, which is received by all battery modules N, is consolidated by the master battery module m in step S2 and sent to a control device of the electric vehicle via a vehicle CAN bus.

[0069] Subsequently, in step S3, it is determined which battery module has the highest voltage value (UPackN max) in each battery module, and a threshold value dVüm is determined to assess whether the voltage of a respective battery module is within a specified tolerance range. Furthermore, based on the voltage values ​​in each battery module, a sequence for connecting the battery modules is determined, with the sequence being determined from the battery module with the highest voltage value to the battery module with the lowest voltage value.

[0070] After the control device of the electric vehicle has transmitted a connection signal to the battery modules via the vehicle CAN bus (step S4) and received by the battery modules (step S5), it is first determined for the battery module i with the highest voltage value whether its voltage lies within the specified tolerance range. If this is the case, a check is carried out in step S6 to determine whether a local fault has occurred. If this is not the case, an HV contactor for the respective battery module can be closed. Subsequently, a check is carried out in step S8 to determine whether the HV contactor has actually been closed. If this is not the case, a check is carried out in step S9 to determine whether a systemic fault has occurred. If such a fault does not exist, a check is carried out again in step S10 to determine whether a local fault has occurred for the respective battery module.The status of the respective battery module is transmitted accordingly to all battery modules in step S11, after which the master battery module m transmits the consolidated and updated battery module data to the electric vehicle's control device via the vehicle CAN bus in step S12. This procedure is repeated accordingly for all battery modules in the specified sequence (see step S13 and point E) until all battery modules have closed their contactors or logged the presence of a local fault (see step C).

[0071] The transmission of the battery module data (step S14) and the transmission of the consolidated battery module data to the control device of the electric vehicle (step S15), as well as the determination of the sequence of the battery modules (step S18), can occur continuously or periodically, respectively, and continues accordingly until the battery modules receive a command from the control device via the vehicle CAN bus in step S16 to open the HV contactors. Such a command accordingly causes the battery modules to open their HV contactors (step S17). Such a measure can also be provided if a systemic error has been detected, as shown in point D.

[0072] Figure 6 shows a further block diagram or algorithm which enables the determination of the master battery module based on the internal logic of each of the battery modules. Accordingly, a master battery module can initially be specified in the logic and / or based on a so-called "pinning". The remaining battery modules can initially be provided as slaves. However, a prioritization is defined in the logic of each battery module, according to which the battery modules can take over the function of the master battery module according to the prioritization if, for example, the current master battery module is no longer available. This assignment and prioritization is shown schematically or algorithmically in step S19.

[0073] Accordingly, it is provided that all battery modules communicate their assignment to each other in the form of battery module data (step 20), preferably via a battery CAN bus. Accordingly, each battery module has the same information and can determine whether it should (initially) communicate and / or function as a master battery module or a slave battery module. The master battery module consolidates the battery module data and transmits it to the control device of the electric vehicle in step S21.

[0074] If it is determined in step S22 that the current master battery module is no longer available, for example, because a corresponding still-alive message is not received, the battery module x with the next highest priority takes over the function of the master battery module (step S24) if the battery module is correspondingly available (step S23). However, if this battery module x is not available, the function of the master battery module can be enabled for the next battery module (x=x+1) based on the corresponding prioritization.

[0075] In this way, even if the current master battery module is no longer available, a battery module can be deployed almost instantly as the next master battery module, ensuring protocol-compliant communication with the electric vehicle's control unit via the vehicle CAN bus and avoiding significant battery system performance loss. Because each battery module has the same logic and the same battery module data, determining the master battery module is free of any conflicts, especially since each battery module reaches the same result in this regard.

[0076] Where applicable, all individual features presented in the embodiments may be combined and / or interchanged without departing from the scope of the invention.

[0077] Battery system

[0078] 12 Battery module

[0079] 12a master battery module

[0080] 12b Master battery module

[0081] 14 Battery CAN bus

[0082] 16 Control device

[0083] 18 Vehicle CAN bus

[0084] 20 Battery module data

[0085] 22 Consolidated battery module data

[0086] Connection command

[0087] Error message

[0088] S1-S26 Logic flow steps

Claims

Claims 1 . A method for controlling / regulating a battery module (12) in a battery system (10) of an electric vehicle having a plurality of battery modules (12), comprising the steps: Collecting battery module data (20) in each battery module (12); Transferring the battery module data (20) from a respective battery module (12) to each other battery module (12); and Determining, in each battery module (12) by means of an electronic control unit of the respective battery module (12), a measure to be carried out by the respective battery module (12) based on the received battery module data (20) and the battery module data (20) acquired by the respective battery module (12), wherein a logic is identical for each electronic control unit and wherein the determination of the measure takes place independently of a master battery module (12a; 12b) of the battery modules (12).

2. Method according to claim 1, wherein the measure is determined exclusively in the respective battery module (12).

3. Method according to claim 1 or 2, wherein each battery module (12) is identically designed.

4. Method according to one of the preceding claims, wherein the battery module data (20) are transmitted to each battery module (12) by means of a battery CAN bus (14) separate from a control device (16) of the electric vehicle.

5. Method according to one of the preceding claims, wherein the measure is a change of the switching state, in particular a connection of the respective battery module (12).

6. The method according to claim 5, wherein the battery module data (20) comprise the switching state of the respective battery modules (12), wherein the battery modules (12) switch on upon receiving a switch-on command (24) from a control device (16) of the electric vehicle based on a predetermined sequence of the battery modules (12) and the received switching states.

7. The method according to claim 6, wherein the order of the battery modules (12) is predetermined based on a prioritization recorded in the logic.

8. The method according to claim 6, wherein the battery module data (20) comprise voltage data of the respective battery modules (12) in the non-connected state, wherein the order of the battery modules (12) in each battery module (12) is determined starting from the battery module (12) with the highest voltage and in descending voltage of the battery modules (12).

9. The method according to claim 7 or 8, wherein the battery module data (20) comprise voltage data of the respective battery modules (12) in the non-connected state, wherein the respective battery module (12) only connects when it determines that its measured voltage lies within a predetermined voltage range.

10. The method according to claim 9, wherein the maximum value of the voltage range is predetermined by the battery module (12) having the highest voltage and the minimum value of the voltage range is predetermined by the maximum value reduced by a predetermined voltage value or predetermined percentage.

11. Method according to one of the preceding claims, wherein only the master battery module (12a; 12b) transmits battery module data (20) to a control device (16) of the electric vehicle.

12. The method according to claim 11, wherein each battery module (12) receives data from a control device (16) of the electric vehicle by means of a vehicle CAN bus (18) and the master battery module (12a; 12b) transmits the battery module data (20) to the control device (16) via the vehicle CAN bus (18).

13. The method according to claim 11 or 12, wherein the battery module data (20) transmitted to the control device (16) comprise or consist of consolidated battery module data (22).

14. Method according to one of the preceding claims, wherein in each battery module (12) it is determined by means of the electronic control unit of the respective battery module (12) and based on the received battery module data (20) and battery module data (20) acquired by the respective battery module (12) whether the respective battery module (12) should assume the function of a master battery module (12a; 12b).

15. The method according to claim 14, wherein the battery module data (20) comprise still-alive messages, wherein in the absence of a still-alive message of a battery module (12a; 12b) specific battery module (12), each battery module (12) again determines whether it should take over the function of the master battery module (12a; 12b).

16. The method according to claim 14 or 15, wherein the determination of the master battery module (12a; 12b) is carried out on the basis of a prioritization recorded in the logic.

17. The method according to any one of the preceding claims, wherein each battery module (12) consolidates the received battery module data (20) and acquired battery module data (20).

18. Method according to one of the preceding claims, wherein the battery module data (20) comprise state of charge data (SOC), state of health data (SOH), functional state data (SOF) and / or voltage data of the battery modules.

19. Method according to one of the preceding claims, wherein the battery module data (20) of a respective battery module (12) comprise an error message (26) when an error is detected by the respective battery module (12), wherein in the case of a local error the respective battery module (12) preferably opens its closed HV contactor and / or in the case of a systemic error all battery modules (12) preferably open their closed HV contactors based on the error message (26).

20. The method according to any one of the preceding claims, wherein, in the event of a vehicle-side systemic fault, the battery modules (12) receive a systemic fault message (24) from a control device (16) of the electric vehicle via a vehicle CAN bus (18) and, in response thereto, activate their rapid shutdown.

21. Method according to one of claims 19 or 20, wherein in the case of a local fault, the respective battery module (12) logs the fault in a fault memory of the respective battery module (12) and / or wherein in the case of a systemic fault, all battery modules (12) log the fault in a respective fault memory.

22. Battery system (10) for an electric vehicle, comprising at least two battery modules (12), each battery module (12) having its own electronic control unit, wherein each battery module (12) is configured to acquire battery module data (20) of the respective battery module (12) and to transmit said data to each other battery module (20), wherein a logic for each electronic control unit is identical and wherein each electronic control unit is configured to determine a measure to be carried out by the respective battery module (12) based on the received battery module data (20) and the battery module data (20) acquired by the respective battery module, independently of a master battery module (12a; 12b) of the battery modules (12).

23. Battery system (10) according to claim 22, wherein the battery modules (12) are communicatively connected to one another via a battery CAN bus (14) for transmitting the battery module data (20).

24. Battery system (10) according to claim 22 or 23, wherein each of the battery modules (12) is connectable to a vehicle CAN bus (18) for receiving data from a control device (16) of the electric vehicle, and wherein only one master battery module (12a; 12b) of the battery modules (12) is configured to transmit battery module data (20) via the vehicle CAN bus (18). CAN bus (18) to the control device (16).

25. Battery system (10) according to one of claims 22 to 24, which is configured to carry out the method according to one of claims 1 to 21.

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