Method for operating a battery system

Abstract

This invention relates to a method for operating a battery system. The battery system includes multiple branches connected in parallel to each other, each having at least one battery module. In the at least one battery module, multiple individual battery cells are connected in series and / or parallel circuits. The branches are capable of being connected and disconnected from each other. Individual battery cells and / or groups of individual battery cells, each comprising multiple parallel-connected battery cells, are capable of being connected, disconnected, and bridging each other. The method includes at least the following steps: identifying a fault in a battery cell; disconnecting and bridging the faulty battery cell and / or the faulty group of battery cells containing the faulty battery cell; disconnecting the faulty branch containing the faulty battery cell and / or the faulty group of battery cells; comparing the branch voltage of the faulty branch with the branch voltage of a normally functioning branch, wherein no fault is identified; and discharging the normally functioning branch when the voltage difference between the branches exceeds a voltage threshold.

Description

Technical Field

[0001] This invention relates to a method for operating a battery system. The battery system includes multiple branches connected in parallel, each having at least one battery module. Within each at least one battery module, multiple individual battery cells are connected in series and / or in parallel circuits. Each branch can be independently switched on and off. Furthermore, each individual battery cell, or each group of individual battery cells comprising multiple parallel-connected battery cells, can be independently switched on and off.

[0002] The present invention also relates to a battery system configured to perform the method proposed in accordance with the present invention.

[0003] The present invention also relates to a vehicle configured to perform the methods proposed in accordance with the present invention and / or include a battery system proposed in accordance with the present invention. Background Technology

[0004] In today's electric vehicles, multiple battery cells are connected not only in series but also in parallel. This results in sufficiently high battery capacity and thus a long driving range, while also providing the necessary power. Typically, such parallel circuitry of battery cells is implemented within the battery module, where multiple battery modules are connected in series to achieve the required battery voltage. A Cell Supervising Circuit (CSC), subordinate to each battery module, measures the voltage and temperature of each individual battery cell within the module and forwards this information to the higher-level Battery Control Unit (BCU) for further evaluation.

[0005] Autonomous electric vehicles (EVs) have specific requirements, particularly regarding their driving capabilities, as breakdowns are unacceptable. These vehicles must meet specific safety levels (Safe-Stop-Level, SSL) based on their level of automation. To this end, vehicles are classified according to different risk levels (Automotive Safety Integrity Level, ASIL), which is associated with increased requirements for battery design. Systems less prone to failure, or even systems that tolerate failure, may imply redundancy in individual components, i.e., multiplication, up to a multiplication of the entire battery system.

[0006] The drawbacks of this redundancy—such as structural space and, especially, cost—are particularly pronounced for the most expensive components of the drivetrain and battery. Initial approaches moved in the direction of not only constructing the battery in a single branch—that is, connecting all individual battery cells or parallel-connected battery cells in series—but also constructing the battery from two or more battery modules connected in parallel. Multiple parallel-connected battery modules imply only a limited increase in structural space, as the individual battery cells must be halved or even quartered according to their capacity.

[0007] If a single battery cell is damaged due to a fault, the battery module with the faulty cell is immediately disconnected, or the entire branch may be disconnected if multiple modules in a branch fail. In battery modules with coupling devices at each battery cell, the faulty cell can be bridged in case of a fault. However, in such a battery system, this means that all functional battery cells from all other branches of the battery system must also be bridged separately to obtain the same voltage in the branches. The same applies to battery systems with modules connected in parallel; the battery system thus loses its functional battery cells.

[0008] Document US 2012 / 0091964 A1 discloses a bypass circuit for a battery and, more particularly, a series bypass circuit for a vehicle battery system, the bypass circuit disconnecting one or more battery cells or modules in the battery system in response to a cell-or-module failure or potential cell-or-module failure, and bypassing the failure by means of a bypass.

[0009] Document US 2016 / 0240894 A1 describes a battery management system for monitoring and regulating the operation of a rechargeable battery having a plurality of battery modules electrically connected to each other, each including at least one battery cell, wherein the battery management system includes at least one controller unit and at least one cell monitoring unit, and wherein the at least one cell monitoring unit is configured to: receive data on at least one operating parameter of at least one battery cell, detect the received data, and transmit the detected data to at least one controller unit. Summary of the Invention

[0010] A method for operating a battery system for vehicles, particularly electric vehicles, is proposed. The battery system comprises multiple branches connected in parallel to each other, each having at least one battery module. Within the at least one battery module, multiple individual battery cells are connected in series and / or in parallel circuits. Each branch can be independently switched on and off.

[0011] Each individual battery cell is preferably independently connectable and disconnectable. Here, the battery system includes a first coupling device within each battery module, which enables the individual battery cells within the battery module to be disconnected and connected via a bypass line, and a second coupling device is housed within the bypass line.

[0012] The individual battery cells can advantageously be combined into multiple battery cell groups, each battery cell group comprising multiple battery cells connected in parallel. Here, the battery system includes a first coupling device within each battery module, within which each battery cell group can be disconnected using the first coupling device and can be bridged via a bypass line, a second coupling device being housed within the bypass line.

[0013] The battery system may include a battery control unit for monitoring at least one battery module and for operating a main switch and / or first and second coupling devices. The at least one battery module may include a single-cell monitoring unit with sensors for detecting measurements of the single battery cell and the at least one battery module. Here, the single-cell monitoring unit communicates with the battery control unit. Here, the battery control unit may include evaluation electronics for evaluating the measurements detected by the sensors of the single battery cell and the at least one battery module.

[0014] For example, the temperature and voltage of each individual battery cell, as well as the temperature and voltage of the entire battery module, are measurements detected by the sensor.

[0015] Furthermore, the battery system can be implemented such that it has a first coupling device that allows the battery module to be disconnected from the branch and can be bridging via a bypass line, the bypass line including a second coupling device.

[0016] According to the present invention, faults in a single battery cell are first identified. This can be achieved by evaluating the measured values. A fault in a single battery cell is understood as a single-cell fault or an electronic component fault, which occurs at the electronic components assigned to the single battery cell, such as, for example, a battery monitoring unit or a sensor.

[0017] The faulty individual battery cell or the faulty battery pack is then disconnected and bridged, with the faulty individual battery cell located within the faulty battery pack. Here, the faulty individual battery cell or the faulty battery pack remains permanently bridged.

[0018] Simultaneously disconnect the faulty branch of the faulty battery cell or the faulty battery pack.

[0019] The branch voltage of the faulty branch was then compared with the branch voltage of the respective functional branches, and no fault was identified in the functional branches.

[0020] Subsequently, when the voltage difference between the branches exceeds a voltage threshold, the functional branch is discharged. The faulty branch remains disconnected until the branch voltage of the functional branch is almost at the level of the faulty branch. Here, the functional branch provides energy for the electric vehicle and provides a correspondingly higher branch current.

[0021] When the voltage difference between the branches does not exceed the voltage threshold, the faulty branch is preferably connected.

[0022] At the same voltage level, all branches are available and can therefore provide their maximum power until the discharge termination voltage is reached. The energy loss ultimately reflected in the driving range is solely due to the duration of the voltage adaptation phase and the discharge current. This advantageously results in improved availability and reliability of traction supply, thereby enabling any level of safe stopping.

[0023] The voltage threshold is preferably in the range of 1V to 2V. This prevents damage to the battery's balance current.

[0024] When the regeneration process occurs, the faulty branch is preferably connected. Here, the functional battery cells in the faulty branch are continuously charged by the regeneration current until voltage adaptation (Spannungsangleichung) is achieved in that branch. Afterward, the functional battery cells in all branches are charged.

[0025] Therefore, the vehicle can continue to operate without restrictions and can be repaired subsequently. If no single battery cell or battery module replacement occurs and the electric vehicle's battery is not being charged, it is preferable to charge all branches while charging the battery system. Here, the charging process ends when the branch voltage decreases by the magnitude of one or more single-cell voltages.

[0026] As an alternative, the functioning branches can be fully charged first while the battery system with the faulty branch that has been disconnected is being charged. After the functioning branches are fully charged, the discharge process is performed on the functioning branches until the branch voltages of all branches are at the same level.

[0027] Preferably, the faulty branch is disconnected only when the branch current of the faulty branch does not exceed a current threshold, and an electronic component fault is detected. The current threshold is preferably in the range of 15A to 25A.

[0028] Furthermore, the method proposed in this invention can be performed such that the battery module is disconnected when a battery fault and / or battery module fault is detected.

[0029] Furthermore, a battery system configured to perform the method proposed in accordance with the present invention is proposed.

[0030] A vehicle is also proposed that is configured to perform the method proposed in accordance with the present invention and / or the vehicle includes a battery system proposed in accordance with the present invention.

[0031] Advantages of the present invention

[0032] Using the method proposed in this invention, a battery system can operate under fault conditions with the maximum possible capacity simultaneously, while saving costs and construction space. The implementation of the method proposed in this invention is based on purely software technology and therefore requires no additional hardware, such as electronic components for the battery system.

[0033] Here, redundant battery modules are not required for the battery system. The method proposed in this invention allows the voltage of a functioning battery module or branch to be adapted to the voltage of a faulty battery module or branch. This minimizes the reduction in driving range and thus similarly improves the availability and reliability of traction supply for achieving any level of safe stopping. Furthermore, the method proposed in this invention is only used in fault conditions, thereby minimizing the load on the battery control unit of the battery system.

[0034] The method proposed in accordance with the present invention can also be used to describe multiple faults within a battery module or branch, or to describe multiple faults across battery modules or branches.

[0035] Furthermore, the method proposed according to this invention is independent of faults and can therefore be used for single-cell faults or electronic component faults. Moreover, the method proposed according to this invention can be used not only for individual cells but also for battery modules in battery systems with coupling devices. Attached Figure Description

[0036] Embodiments of the present invention will be further explained with the aid of the accompanying drawings and the following description.

[0037] in:

[0038] Figure 1 The structure of a four-branch battery system with single battery cells connected in parallel and series is shown;

[0039] Figure 2The structure of a three-branch battery system using a 1p-arrangement scheme is shown;

[0040] Figure 3 An electric drive system with a three-branch battery system employing a 1p-arrangement scheme is shown, the three-branch battery system having a single-cell battery coupling device;

[0041] Figure 4 A battery module with battery cells connected in series using a 3p-arrangement scheme is shown, the battery module having a battery cell coupling device;

[0042] Figure 5 A battery module with a 1p-arrangement is shown, the battery module having coupling devices assigned to the battery module in the main and bypass lines;

[0043] Figure 6 A battery module employing a 3p-arrangement is shown, the battery module having coupling devices allocated to it in the main and bypass lines; and

[0044] Figure 7 An illustrative method flow diagram is shown according to the method proposed in this invention for operating a fault-tolerant battery system. Detailed Implementation

[0045] Figure 1 The structure of a battery system 10 with four branches 12 is shown. Each of the four branches includes a battery module 18, 20, 22, 23, a first branch contactor 14, and a second branch contactor 16. (From...) Figure 1 As shown in the diagram, each of the battery modules 18, 20, 22, and 23 is equipped with a single-cell monitoring unit 36. The battery modules 18, 20, 22, and 23 are configured such that the single cells 24, 26, 28, and 30 within each module are interconnected in a 12-series-3-parallel circuit (12s3p-Schaltung) 32. According to... Figure 1 As illustrated in the diagram, the battery system 10 includes four battery control units 40, each connected not only to a first branch contactor 14 but also to a second branch contactor 16, and also communicating with the individual battery monitoring units 36 of each battery module 18, 20, 22, 23 via communication lines 42, such as a controller area network bus (CAN-Bus). Figure 1 As illustrated in the diagram, the battery system 10 further includes a first main contactor 60 and a second main contactor 62 for connecting and disconnecting the battery system 10.

[0046] exist Figure 1In the battery system 10 shown, typically ten to twelve individual battery cells 24, 26, 28, 30 constitute a battery module 18, 20, 22, 23. If multiple battery modules in such battery modules 18, 20, 22, 23—and thus, for example, eight to ten battery modules—are connected in series with each other, then the required battery voltage of, for example, 400V is achieved.

[0047] From according to Figure 2 As shown in the diagram, the battery system 10 includes three branches 12. Within each of these branches 12, protected by a first branch contactor 14 and a second branch contactor 16, there resides a first battery module 18, a second battery module 20, and a third battery module 22, wherein the battery modules 18, 20, and 22 are connected in series. As further shown in the diagram... Figure 2 As shown in the diagram, the individual battery cells 24, 26, 28, and 30 within each battery module 18, 20, and 22 are connected in series within the range of circuit 34. Figure 2 The diagram shown is also referred to as 1p-arrangement scheme 48. According to... Figure 2 As illustrated in the diagram, each of the battery modules 18, 20, and 22 is equipped with a single-cell monitoring unit 36 ​​with sensors not shown here. The battery system 10 further includes a battery control unit 40, which communicates with the single-cell monitoring unit 36 ​​via communication line 42.

[0048] It can also be arranged in a 2p-layout or a 3p-layout scheme (refer to the following). Figure 1 (as shown in the diagram) to form the individual battery modules 18, 20, and 22, in order to replace the existing ones. Figure 2 The 1p-arrangement scheme 48 shown is based on... Figure 2 As shown in the diagram, all battery modules 18, 20, and 22 have the same structure.

[0049] exist Figure 1 and Figure 2 The battery system 10 shown is only permissible in the following circumstances: in the event of a failure, battery modules 18, 20, 22, 23 or branch 12 are disconnected, which is accompanied by a reduction in capacity and therefore a reduction in power.

[0050] In the following description of embodiments of the invention, the same or similar elements are indicated by the same reference numerals, wherein, in individual cases, repeated descriptions of these elements are omitted. The drawings are merely schematic representations of the subject matter of the invention.

[0051] Figure 3An electric drive system 100 is shown. The electric drive system 100 includes a three-branch battery system 10 and a motor 80. Here, the battery system 10 has an inverter 70 connected to the motor 80.

[0052] From according to Figure 3 As shown in the diagram, each branch 12 includes a battery module 18, 20, and 22. Here, the first branch 12 includes a first battery module 18, the second branch 12 includes a second battery module 20, and the third branch 12 includes a third battery module 22. The three battery modules 18, 20, and 22 of the battery system 10 each include a single-cell monitoring unit 36. In each battery module 18, 20, and 22, the single cells 24, 26, 28, and 30 are connected in series by a circuit 34. (This is in accordance with...) Figure 2 The designs of battery modules 18, 20, and 22, which are also connected in series using circuit 34, differ in that... Figure 3 In the battery modules 18, 20, and 22 shown, a first coupling device 44 is provided in the battery system 10 of the main line 52 of branch 12. In the battery modules 18, 20, and 22 according to a variant design... Figure 3 Each of the battery cells 24, 26, 28, and 30 shown in the diagram is assigned a bypass line 54, in which a second coupling device 46 is present respectively.

[0053] If according to Figure 3 If any of the individual battery cells 24, 26, 28, or 30 of battery modules 18, 20, or 22 fails, the first coupling device 44 assigned to that individual battery cell 24, 26, 28, or 30 is disconnected, thereby enabling the disconnection of the relevant individual battery cell 24, 26, 28, or 30. This is achieved by closing the second coupling device 46 in the bypass lines 54 assigned to the individual battery cells 24, 26, 28, or 30 to be disconnected.

[0054] For the sake of completeness, it was mentioned that, in accordance with Figure 3 In the battery modules 18, 20, and 22 of the battery system 10, individual battery cells 24, 26, 28, and 30 are connected in a 1p-arrangement scheme 48.

[0055] The branches 12 of the battery system 10 are assigned a common first branch contactor 14. Each branch 12 includes a second branch contactor 16 for independently disconnecting from the others.

[0056] Here, voltage adaptation is achieved by operating the second branch contactor 16 of the battery modules 18, 20, 22 or branch 12 with defective battery cells 24, 26, 28, 30, instead of bridging the defective battery cells 24, 26, 28, 30 from the battery modules 18, 20, 22, and bridging the other functional battery cells 24, 26, 28, 30 from the remaining battery modules 18, 20, 22 or branch 12 for voltage adaptation purposes. This results in a decrease in voltage and ultimately a decrease in driving range.

[0057] To illustrate the method proposed according to the present invention, it is assumed that a fault exists in the first battery cell 24 of the first battery module 18. Faults may also exist in other one or more battery cells 24, 26, 28, 30 of the battery modules 18, 20, 22 or different battery modules 18, 20, 22.

[0058] If the battery control unit 40—which executes the battery system management system within the battery control unit—detects a fault in the first battery cell 24 of the first battery module 18, whether it is a single-cell fault or an electronic component fault, then it operates the first and second coupling devices 44, 46 of the first battery cell 24 of the first battery module 18 to permanently bridge it. Simultaneously, it switches the second branch contactor 16 of the first branch 12 and disconnects the first branch 12 from the two other branches 12, because a voltage difference exists between the battery modules 18, 20, 22 or the branch 12, which will result in a high balancing current, thereby damaging the battery cells 24, 26, 28, 30 and thus aging them more rapidly.

[0059] Because the branch contactors 14 and 16 should not operate under high load conditions, care should be taken to ensure that the current is not too high at the disconnection point, for example, less than 20A. This can be taken into account in the charging strategy without problems during charging. The situation is different during driving, i.e., during discharging; sudden power disturbances should be avoided here. For fault type identification resulting from single-cell faults that are critical to safety or less critical electronic component faults, in the last mentioned case, the disconnection can be delayed until current conditions are met, such as at traffic lights or during inertial operation when there is no torque demand. However, single-cell faults that are critical to safety must cause disconnection immediately after their identification. Here, the driver can be informed of the possible impending power disturbance by a prompt in the cockpit. The battery management system minimizes the power reduction by distributing the required current to two functional branches 12, specifically the second and third branches 12 or battery modules 20 and 22, and thus loading higher branch currents within permissible limits for the individual cells 24, 26, 28, and 30 of the second and third branches 12 or battery modules 20 and 22. Therefore, the driver only experiences power disturbances during full-load operation, i.e., at maximum torque demand.

[0060] The second branch contactor 16 of the first branch 12 remains open until the voltage of the first and second branches 12 has nearly caught up with the level of the first branch 12 (e.g., until approximately 1V to 2V). During this time, the second and third branches 12 provide energy for the electric vehicle and provide a correspondingly higher branch current as much as possible. If a regeneration process occurs during this phase, the second branch contactor 16 of the first branch 12 is closed, and the functional individual cells 26, 28, and 30 of the first battery module 18 are continuously charged until voltage acclimation is achieved, at which point the second branch contactors 16 of the second and third branches 12 are opened. Thereafter, the individual cells 24, 26, 28, and 30 of all three branches 12 are charged.

[0061] At the same voltage level, all three branches 12 are available and thus able to provide their maximum power until the discharge termination voltage is reached. The energy loss ultimately reflected in the electric vehicle's range is derived solely from the duration of the voltage adaptation phase and the discharge current. This advantageously results in improved availability and reliability of traction supply, thereby enabling any level of safe stopping.

[0062] Therefore, driving can continue without restriction, and maintenance can be performed afterward. If there is no single-cell battery replacement or battery module replacement and the electric vehicle's battery is not charged, the charging process can be terminated either when the branch voltage is reduced by the magnitude of a single-cell voltage. Alternatively, the two functional branches 12 can also be fully charged by disconnecting the second branch contactor 16 of the first branch 12. In this case, the discharge process is carried out using the disconnected second branch contactor 16 of the first branch 12 as described above until the voltages of the three branches 12 are at the same level.

[0063] Advantages of this structure include the ability to handle multiple faults in battery modules 18, 20, 22 or branch 12, i.e., so-called dual faults or multiple faults. Even faults in different branches 12 can be described using the method proposed in this invention. The method proposed in this invention offers the advantage that, apart from the faulty battery cells 24, 26, 28, 30, other battery cells 24, 26, 28, 30 do not need to be disconnected, resulting in less mileage reduction. Therefore, in fault conditions, the battery system 10 is maintained at its maximum possible capacity simultaneously without additional hardware.

[0064] Figure 4 A fault-tolerant battery system 10 is shown, comprising a first battery module 18 with first and second coupling devices 44, 46, which are distributed to battery cells 24, 26, 28, 30 connected in a 3p-arrangement scheme 50.

[0065] exist Figure 4 The first battery module 18 is configured such that individual battery cells 24, 26, 28, and 30, which are connected in a 3p-cell battery pack 38, are connected in series by a circuit 34 (e.g., twelve cell battery packs 38). Figure 4 Thus, the first battery module 18 is configured such that the first coupling device 44 in the main line 52 is located before each 3p-arrangement 50 or each battery cell group 38 of the individual cells 24, 26, 28, 30. The bypass line 54 branches before the first coupling device, in which a second coupling device 46 is accommodated.

[0066] By following in Figure 4The illustrated variant of the first battery module 18 allows the first battery module 18 to continue operating even if a single battery cell 24, 26, 28, 30 connected in a 3p-arrangement scheme 50 or a battery cell group 38 is damaged. This is achieved by disconnecting or closing the first and second coupling devices 44, 46, i.e., by bypassing the damaged battery cells 24, 26, 28, 30.

[0067] Figure 5 A first battery module 18 with a 1p-arrangement scheme 48 is shown, the first battery module having coupling devices 44, 46 in the main and bypass lines 52, 54 assigned to the first battery module.

[0068] From according to Figure 5 The illustration shows a fault-tolerant battery system 10, in which, exemplarily selected, a first battery module 18 comprises individual battery cells 24, 26, 28, and 30 connected to each other in series via a circuit 34. The first battery module 18 shows master-slave battery cell monitoring units 36 respectively connected to the individual battery cells 24, 26, 28, and 30 connected to each other in series via the circuit 34.

[0069] As from Figure 5 As further understood, the first coupling device 44 is located in the main line 52, before the first coupling device—in accordance with… Figure 4 A similar variant design involves a branching off of the bypass route 54. A second coupling device 46 is arranged in the bypass route. To disconnect the first battery module 18 from the main line 52, the first coupling device 44 is disconnected and the second coupling device 46 is closed, allowing the first battery module 18, for example, which has been shown to be damaged, to bypass the bypass route 54 within the branch 12 of the battery system 10, and enabling the continued operation of the fault-tolerant battery system 10 as proposed in this invention.

[0070] Figure 6 A first battery module 18 employing a 3p-arrangement scheme 50 is shown, the first battery module being provided with first and second coupling devices 44, 46.

[0071] from Figure 6 It is understood that the first battery module 18 shown therein has several individual battery cells 24, 26, 28, 30 connected in parallel in either a 3p-arrangement scheme 50 or a battery cell group 38. The battery system 10 in... Figure 6The first battery module 18 selected has a first coupling device 44 in the main line 52. Before the first coupling device 44, the bypass line 54 branches, in which a second coupling device 46 is accommodated. If the battery system 10 fails—the battery cells 24, 26, 28, 30 connected in a 3p-arrangement 50 are connected in series by a circuit 34—then the first coupling device 44 is disconnected, the second coupling device 46 in the bypass line 54 is closed, and thus the damaged battery module is bridged, so that only the damaged battery module among the battery modules 18, 20, 22 is disconnected in the battery system 10, and the battery system 10 can continue to operate, albeit with reduced power. The battery system 10, designed to be fault-tolerant according to the invention, ensures the continued operation of the autonomous electric vehicle, ensuring that driving can continue despite reduced power and increased duration, without interruption.

[0072] Figure 7 An illustrative method flow 200 is shown according to the method proposed in this invention for operating a fault-tolerant battery system 10.

[0073] from Figure 7 It can be concluded that, starting from the beginning in method step 201, the method proposed in this invention begins to run.

[0074] First, in method step 202, faults in battery cells 24, 26, 28, and 30 are identified. This can be achieved by evaluating the measured values ​​of said battery cells 24, 26, 28, and 30.

[0075] Subsequently, in method step 203, the faulty individual battery cells 24, 26, 28, and 30, or the faulty battery cell group 38, are disconnected and bridged, wherein the faulty individual battery cells 24, 26, 28, and 30 are located within the faulty battery cell group. Here, the faulty individual battery cells 24, 26, 28, and 30, or the faulty battery cell group 38, remain permanently bridged.

[0076] Simultaneously, in method step 204, the faulty branch 12 is disconnected, the faulty branch having the faulty battery cells 24, 26, 28, 30 or the faulty battery cell group 38.

[0077] Then, in method step 205, the branch voltage of the faulty branch 12 is compared with the branch voltage of the respective functional branch 12, and no fault is identified in the functional branch.

[0078] When the voltage difference between the branches 12 exceeds a voltage threshold, the functional branch 12 is discharged in method step 206. The faulty branch 12 remains disconnected until the branch voltage of the functional branch 12 is almost adapted to the level of the faulty branch 12. Here, the functional branch 12 provides energy for the electric vehicle and provides a correspondingly higher branch current. When a regeneration process occurs during the discharge of the functional branch 12, the faulty branch 12 is turned on. Here, the functional battery cells 24, 26, 28, and 30 of the faulty branch 12 are continuously charged by the regeneration current until the voltage of the branch 12 is adapted. Thereafter, all functional battery cells 24, 26, 28, and 30 of the branches 12 are charged.

[0079] When the voltage difference between the branches 12 does not exceed the voltage threshold, the faulty branch 12 is switched on in method step 207. Then, in method step 208, all battery cells 24, 26, 28, and 30 of all branches 12 are discharged. During the regeneration process, all battery cells 24, 26, 28, and 30 of all branches 12 are similarly charged.

[0080] In method step 209, all branches 12 are again available at the same voltage level and are thus able to provide their maximum power until the discharge end voltage is reached, and the method according to the present invention ends in method step 210 when the battery system 10 is disconnected.

[0081] The invention is not limited to the embodiments described herein and the aspects highlighted therein. Rather, numerous variations within the scope of expertise are possible within the scope defined by the claims.

Claims

1. A method for operating a battery system (10), the battery system comprising a plurality of branches (12) connected in parallel to each other, each having at least one battery module (18, 20, 22, 23), wherein a plurality of individual battery cells (24, 26, 28, 30) in the at least one battery module are connected in series (34) and / or in parallel, wherein, The branches (12) can be connected to and disconnected from each other, and among them, Each individual battery cell (24, 26, 28, 30) and / or each battery cell group (38) comprising multiple parallel-connected individual battery cells (24, 26, 28, 30) can be connected to, disconnected from, and bridging with each other. The method includes at least the following steps: - Identify faults in individual battery cells (24, 26, 28, 30); - Disconnect and bridging faulty battery cells (24, 26, 28, 30) and / or the following faulty battery cell group (38): the faulty battery cells (24, 26, 28, 30) are in the faulty battery cell group; - Disconnect the faulty branch (12) of the faulty battery cell (24, 26, 28, 30) and / or the faulty battery cell group (38). - Compare the branch voltage of the faulty branch (12) with the branch voltage of the respective functional branch (12), and no fault is identified in the functional branch. When the voltage difference between the branches (12) exceeds the voltage threshold, the normally functioning branch (12) is discharged. When a regeneration process occurs during the discharge of the branch (12) that is functioning normally, the faulty branch (12) is switched on.

2. A method for operating a battery system (10), the battery system comprising a plurality of branches (12) connected in parallel to each other, each having at least one battery module (18, 20, 22, 23), wherein in the at least one battery module, a plurality of individual battery cells (24, 26, 28, 30) are connected in series circuit (34) and / or in parallel circuit, wherein, The branches (12) can be connected to and disconnected from each other, and among them, Each individual battery cell (24, 26, 28, 30) and / or each battery cell group (38) comprising multiple parallel-connected individual battery cells (24, 26, 28, 30) can be connected to, disconnected from, and bridging with each other. The method includes at least the following steps: - Identify faults in individual battery cells (24, 26, 28, 30); - Disconnect and bridging faulty battery cells (24, 26, 28, 30) and / or the following faulty battery cell group (38): the faulty battery cells (24, 26, 28, 30) are in the faulty battery cell group; - Disconnect the faulty branch (12) of the faulty battery cell (24, 26, 28, 30) and / or the faulty battery cell group (38). - Compare the branch voltage of the faulty branch (12) with the branch voltage of the respective functional branch (12), and no fault is identified in the functional branch. When the voltage difference between the branches (12) exceeds the voltage threshold, the normally functioning branch (12) is discharged. During the charging of the battery system (10), the functional branch (12) is fully charged. After the charging, the functional branch (12) is discharged while the faulty branch (12) is disconnected until the branch voltage of all branches (12) is at the same level.

3. The method according to claim 1 or 2, characterized in that, When the voltage difference between the branches (12) does not exceed the voltage threshold, the faulty branch (12) is connected.

4. The method according to claim 1 or 2, characterized in that, The voltage threshold is in the range of 1V to 2V.

5. The method according to claim 1 or 2, characterized in that, When the battery system (10) is charged, all branches (12) are charged, and the charging process ends when the branch voltage is reduced by the magnitude of one or more single cell voltages.

6. The method according to claim 1 or 2, characterized in that, When the branch current does not exceed the current threshold, the faulty branch (12) is disconnected only when the electronic component fault is detected.

7. The method according to claim 6, characterized in that, The current threshold is in the range of 15A to 25A.

8. A battery system (10) configured to perform the method according to any one of claims 1 to 7.

9. A vehicle configured to perform the method according to any one of claims 1 to 7 and / or the vehicle includes the battery system (10) according to claim 8.

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