Fault tolerant battery system

Abstract

The invention relates to a fault-tolerant battery system (62). The fault-tolerant battery system comprises branches (28, 84, 86) composed of single cells (42, 44, 46) connected in series circuits (90). The branches (28, 84, 86) are connected in parallel circuits (82). The single cells (42, 44, 46) have a single cell monitoring loop (54) within the battery module, which is connected to a battery control unit (30, 32). A redundant additional single cell monitoring loop (66, 70, 74) connected to the battery control unit (30, 32) is installed on each branch (28, 84, 86) and is activated together with a register (64, 68, 70) for storing analog or corresponding digital values of the data of the branch (28, 84, 86) in the event of a faulty function of the single cell monitoring loop (54) within the battery module.

Description

Technical Field

[0001] This invention relates to a fault-tolerant battery system with branches consisting of individual battery cells connected in a series circuit, wherein the branches are connected in a parallel circuit and each individual battery cell has a single-cell monitoring loop within the battery module and connected to a battery control unit. Furthermore, this invention also relates to the application of the fault-tolerant battery system in electrically driven vehicles or in vehicles powered by a fuel cell single-cell system. Background Technology

[0002] DE 10 2012 203 017 A1 relates to a battery management system, a method for monitoring a battery system, and a battery system incorporating the battery management system. The battery system relates to a high-voltage battery system having multiple battery modules electrically connected to each other. Each of these battery modules comprises multiple battery cells electrically connected to each other. The battery management system has at least one control and / or regulation device to monitor the voltage (U) at a single battery cell or at a group of parallel-connected battery cells of battery modules. C1 …toU Cn The specification stipulates that the battery management system has at least one monitoring device to monitor at least one electrical connection between the battery modules and their connection circuits. The at least one monitoring device operates within a control and / or regulation device, or within at least one of a plurality of control and / or regulation devices, or is a monitoring device separate from at least one control and / or regulation device.

[0003] DE 10 2015 223 580 A1 focuses on battery systems. A battery system for regulating or controlling the branch current used for electric drive comprises multiple individual battery cells. Each individual battery cell includes an interface for receiving numerical values, a random generator for generating random values, and individual cell electronics for switching the individual battery cell on and off based on the random values ​​and the received numerical values. Furthermore, a central regulating device is provided to transmit numerical values ​​to the individual battery cells.

[0004] In today's electric vehicles, multiple battery cells are connected not only in series but also in parallel. This achieves sufficiently high battery capacity and thus long driving range; it also provides the required electrical power. These parallel connections of individual cells mostly occur on the battery module plane, where the modules are robustly interconnected. A cell monitoring loop belongs to each module, measuring the voltage and temperature of each individual cell within the battery module and transmitting this data to the higher-level battery controller for further evaluation. For autonomous vehicles that must meet certain safety standards, this battery design is not a viable option. For fault-tolerant systems, this means doubling all the overhead required for battery system operation. Summary of the Invention

[0005] According to the present invention, a fault-tolerant battery system is proposed, comprising branches consisting of individual battery cells connected in a series circuit, wherein the branches are connected in a parallel circuit, and each individual battery cell has a single-cell monitoring loop within the battery module, the single-cell monitoring loop being connected to the battery control unit. The fault-tolerant battery system includes redundant additional single-cell monitoring loops, which are connected to the battery control unit and installed on each branch, and are activated along with corresponding registers for storing analog data or corresponding digital values ​​of the branch in the event of a malfunction in the single-cell monitoring loop within the battery module. The solution proposed according to the present invention, in the form of a fault-tolerant battery system, allows advantageous achievement, particularly in autonomous vehicles, of the required SSL or ASIL classification, because secure single-cell monitoring is ensured and explicit fault assignment can now be implemented.

[0006] In an advantageous extended design of the solution proposed according to the present invention, a redundant additional single-pool monitoring loop is provided for each branch for all modules in each branch.

[0007] The solution proposed according to the present invention can significantly reduce the number of additional single-pool monitoring loops, since only one additional single-pool monitoring loop is needed for the branch and not for each module in the module for this branch.

[0008] In an extended design of the solution proposed according to the present invention, analog data or digital data representing the corresponding analog data are detected in a register assigned to each branch, particularly the voltage and temperature of the individual battery cells in the branch. The registers assigned to each branch may involve integrated circuits or multiplexing devices.

[0009] In the fault-tolerant battery system proposed according to the present invention, the registers configured for each branch are designed such that the registers include a number of storage spaces corresponding to the number of modules to be monitored, which are composed of individual battery cells of the respective branch.

[0010] This ensures that each module in the branch can store analog data or digital data representing the corresponding analog data in a register or memory, and can call the battery control unit based on this information, for example.

[0011] In an extended design of the solution proposed according to the invention, a selection switch is provided for each branch register, which connects the analog data of the branch, or the digital value of the corresponding analog data, to the input of the corresponding redundant additional single-pool monitoring loop. The register can thus be advantageously connected to and read from each module to be checked in the branch via the selection switch.

[0012] In the solution proposed according to the present invention, the single-cell monitoring circuit inside the battery module is connected to the main battery control unit, while the redundant additional single-cell monitoring circuit used by each branch is connected to the slave battery control unit, which drives the selection switch.

[0013] In the solution proposed according to the present invention, the simulated data of the branch or the numerical value of the corresponding simulated data is persistently stored for each branch.

[0014] Furthermore, the present invention also relates to a method for operating a fault-tolerant battery system, wherein at least the following method steps are performed: a) When the simulated data or the corresponding numerical values ​​obtained by the single-cell monitoring loop inside the battery module in each branch are unreasonable, connect the redundant additional single-cell monitoring loop. b) The branch measured by redundant additional single-pool monitoring loops according to a) the value of the analog or digital value or the corresponding analog value of the digital value is classified as unreasonable, and c) Finally, compare the simulated data from a) and b), or compare the numerical values ​​corresponding to these simulated data, for explicit error detection.

[0015] The method is thus advantageously extended in that the comparison performed according to c) is performed within the scope of comparison using limit values ​​as exceeding or falling below the threshold.

[0016] Furthermore, the present invention also relates to the application of battery systems in electrically driven vehicles or to the application of battery systems in vehicles powered by a fuel cell system.

[0017] By employing the fault-tolerant battery system proposed according to the present invention, which has a redundant additional single-cell monitoring loop for each branch of the battery system, a clear fault allocation can be achieved in battery systems constructed with single or multiple branches. This results in the decisive advantage that the fault-tolerant battery system proposed according to the present invention can achieve gradation to meet SSL and ASIL standards, thus enabling its use in autonomous vehicles. The fault-tolerant battery system proposed according to the present invention presupposes significantly reduced hardware costs, thus enabling a higher level of security at a relatively low cost, thereby meeting the requirements of SSL and / or ASIL standards. Furthermore, fewer components in the form of additional single-cell monitoring loops can be used in the fault-tolerant battery system proposed according to the present invention, which advantageously impacts cost. Additionally, in the solution proposed according to the present invention, standard components can be used, that is, single-cell monitoring loops with redundant additional single-cell monitoring loops that can be used according to standards, which also advantageously impacts cost.

[0018] The solution proposed according to this invention enables precise error detection regarding the determination of individual battery cell errors or sensor or electronic device errors.

[0019] If the fault-tolerant battery system proposed according to the present invention is used, a complete failure of the single-cell monitoring circuit inside the battery module will not necessarily cause the vehicle, especially an autonomous vehicle, to stop, because the function of the single-cell monitoring circuit inside the faulty battery module can be taken over by the additional single-cell monitoring circuits present in the branch circuits.

[0020] Furthermore, in operating the fault-tolerant battery system proposed according to this invention, signal drift is identified early, which is done while the measured values ​​are stored in the register. Therefore, faults can be identified promptly within the scope of pre-diagnosis, as changes in the measured values ​​indicating such a fault can be reacted accordingly.

[0021] The proposed solution according to the invention achieves explicit error detection by determining whether the error pertains to a single cell or to a sensor or electronic component. In the proposed solution, a redundant additional cell monitoring loop can be activated in case of unreasonable measurements. This redundant loop is activated regardless of whether the sensor or cell is faulty, and thus measures analog data, such as voltage values, even when an error is suspected. Comparison of these measurements achieves the aforementioned explicit error detection.

[0022] Embodiments of the invention will be explained in more detail with the aid of the accompanying drawings and the following description. Attached Figure Description

[0023] Figure 1 A diagram of a battery system designed as a dual-branch system is shown. Figure 2 This is a first implementation variant of the fault-tolerant battery system proposed in this invention, with one branch. Figure 3 A diagram of a fault-tolerant battery system with three single cells connected in parallel is shown; and Figure 4 This is another implementation variation of the fault-tolerant battery system proposed in this invention, which has three branches. Detailed Implementation

[0024] Figure 1 It is known that a battery system, in this case, is designed as a battery system with two branches.

[0025] Depend on Figure 1 It is understood that the battery system 10 includes a certain number of uniformly constructed battery modules 12. The battery system 10 includes a first module branch 14 and a second module branch 16, wherein, in accordance with... Figure 1 In the diagram, four identical battery modules 12 are housed in corresponding module branches 14 and 16. Each module branch 14 and 16 is equipped with a first contactor 18 or a second contactor 20, by means of which a single module branch 14 or 16 can be completely shut off. Furthermore, by means of... Figure 1 As shown in the diagram, each identically constructed module in module 12 has a single-cell monitoring loop 22 of the form CSC. The module branches 14 and 16 of the battery system 10 are arranged according to... Figure 1 The configuration shown in the diagram is in parallel circuit 26 and operates with the aid of battery control unit 24 (BCU).

[0026] against Figure 1 The battery system 10 shown, with two module branches 14 and 16, requires a certain number of single-cell monitoring loops 22 (CSCs). If 12 or more modules are installed in each module branch 14 and 16, then a correspondingly larger number of single-cell monitoring loops 22 are required. If the battery system 10 is also to be fault-tolerant, then each module 12, for example, requires an additional single-cell monitoring loop 22. This means that for... Figure 1 The battery system 10 shown, assuming a corresponding number of battery modules 12, requires up to 40 single-cell monitoring loops 22. When the battery system is also as described... Figure 1 When there are more than two module branches 14 and 16 as shown, this results in a huge additional overhead.

[0027] In the following description of embodiments of the invention, the same or similar elements are labeled with the same reference numerals, wherein repeated descriptions of these elements in individual cases are omitted. The drawings are for illustrative purposes only, showing the subject matter of the invention.

[0028] Figure 2 A first embodiment of the fault-tolerant battery system 62 proposed according to the present invention, with a first branch 28, is shown.

[0029] By pressing Figure 2 As shown in the diagram, the first branch 28 includes, for example, 12 modules 36, 38, ..., 40. Within the first branch 28, the modules 36, 38, ..., 40 are connected in series. Figure 2 The modules 36, 38, ..., 40 of the first branch 28 each include battery cells 42, 44, ..., 46, for example, 12 battery cells, each of which is connected in series circuit 34. Furthermore, each module of the first branch 28 includes a single-cell monitoring loop 54 (CSC) within the battery module.

[0030] Depend on Figure 2 It can be seen that the single-cell monitoring circuit 54 inside each battery module is connected to the main ECU, that is, the main battery control unit 30.

[0031] First branch road 28 Figure 2 The diagram shows that it can be switched by contactors 18 and 20.

[0032] To illustrate the fault-tolerant battery system 62, according to the present invention, for example, to... Figure 2 The first branch 28 in the diagram is equipped with register 48. This register 48 can be implemented, for example, as an IC (integrated circuit), operating according to the principle of a "bucket chain charge-coupled device" (BBD), and can also be constructed as a multiplexing device. Register 48 includes register space 50. Figure 2The diagram indicates that register 48 can have register spaces 50.1 to 50.8, where the number of register spaces 50 in register 48 corresponds to the number of modules 36, 38, ..., 40 connected in series within the first branch 28. For example, if register 48 is equipped with eight register spaces 50.1 to 50.8, then eight battery modules can be connected within the first branch 28. A redundant additional single-cell monitoring loop 56 is provided for register 48. However, the redundant additional single-cell monitoring loop 56 alone is not capable of detecting analog data, such as a single cell voltage and the temperature of one or more modules of modules 36, 38, ..., 40. Analog data for each module 36, 38, ..., 40 in the first branch 28 is stored in its respective register space 50 of register 48. A selection switch 52 is provided between register 48 and the redundant additional single-cell monitoring loop 56. This selector switch can be switched on and off in stages and has exactly as many stages as the single-cell monitoring loops 54 within each branch of the modules 36, 38, ..., 40 or battery modules. Analog measurements in the form of single voltage and model temperature are fed, for example, to the input of a redundant additional single-cell monitoring loop 56 via the selector switch 52 connected after register 48. This redundant additional single-cell monitoring loop 56 is advantageously designed as a standard component and converts the analog values ​​into digital values ​​via an A / D converter, so that these values ​​can be relayed, for example, to a battery control unit in the form of a subordinate BCU32 for further processing.

[0033] By pressing Figure 2 This structure reduces the error variability of the A / D converter because it exists only once within the redundant single-cell monitoring loop 56. Alternatively, it is possible to design register 48 such that it stores the digital value. However, in this case, each battery module 36, 38, ..., 40 uses one A / D converter and a modified redundant additional single-cell monitoring loop 56, which can function as described above even without the A / D converter assembly.

[0034] Press Figure 1 The selection switch 52 shown in the diagram, between register 48 and redundant additional single-cell monitoring loop 56, is controlled by a battery control unit designed to be subordinate to BCU32.

[0035] also, Figure 2 This indicates that all modules installed in the first branch 28 according to the standard for each battery module 36, 38, ..., 40 are directly connected to the battery control unit used as the main BCU30.

[0036] In cases where measurement values ​​are unreasonable, such as when the voltage of a single cell is lower than a predetermined threshold compared to the voltage of another single cell, a redundant additional single-cell monitoring circuit 56 is activated. Regardless of whether the sensor or single cell is faulty, activating the redundant additional single-cell monitoring circuit 56 allows it to measure simulated data, such as voltage values, even in cases of suspected error. Comparison of the measured values ​​allows for clear error detection and confirms the fault of the corresponding component, i.e., the single cell or sensor.

[0037] Therefore, for each of the modules 36, 38, ..., 40, the single-cell monitoring circuit 54 within the battery module should, for example, assume the function of a redundant additional single-cell monitoring circuit 56 in the event of an A / D converter failure. However, in this case, a double error cannot be handled, meaning that in such an error situation, the vehicle should be sent to the workshop to avoid hindering vehicle performance and SSL maintenance.

[0038] Figure 3 The structure of a battery system 10 is shown schematically, in which a single battery cell 58 is shown connected in parallel in a parallel circuit 26. (The last sentence appears to be incomplete and possibly refers to a different topic.) Figure 3 The module is equipped with a monitoring loop 60 (CSC).

[0039] By pressing Figure 4 The illustration shows another embodiment of the fault-tolerant battery system 62 with three branches 28, 84, 86 proposed according to the present invention.

[0040] The button with three branches 28, 84, and 86 Figure 4 The diagram and the button including the first branch 28 Figure 2 The illustrations show that in the fault-tolerant battery system 62 with three branches 28, 84, and 86, each branch 28, 84, and 86 also has only one redundant additional single-cell monitoring loop 56. There are selection switches 76, 78, and 80 between these additional single-cell monitoring loops and the register 48 of each branch 28, 84, and 86, wherein the first register 64 is connected to the first additional single-cell monitoring loop 66 via the first selection switch 76. This is accomplished by driving the first selection switch 76 via the battery control unit 32, which acts as a slave BCU. The situation is similar in the second branch 84, where the second register 68 can be connected to the second additional single-cell monitoring loop 70 by driving the second selection switch 78. The same applies to the third branch 86 of the fault-tolerant battery system 62 with three branches 28, 84, and 86; the third selection switch 80 is operated by the slave BCU, namely the battery control unit 32, to connect the third register 72 to the third additional single-cell monitoring loop 74.

[0041] In addition, by Figure 4 It can be seen that there are series circuits 88 of corresponding modules 36, 38, ..., 40 in branches 28, 84, and 86, and series circuits 90 of individual battery cells 42, 44, ..., 46 in each module 36, 38, ..., 40 in branches 28, 84, and 86.

[0042] Replace in Figure 4 The three modules 36, 38, ..., 40 shown in each branch 28, 84, 86 are allowed to be used in each branch 28, 84, 86, up to 12 or more battery modules in series circuit 88.

[0043] The solution proposed according to the present invention can eliminate a large number of redundant additional single-cell monitoring loops 56, especially for maintaining high safety standards, because the transmission of information from each battery module 36, 38, ..., 40 of each branch 28, 84, 86 to the input of the corresponding redundant additional single-cell monitoring loop 56 can be connected by the corresponding registers 64, 68, 72 and the corresponding selection switches 76, 78, 80, which greatly saves hardware components.

[0044] Despite pressing Figure 2 and Figure 4 The illustrations show only fault-tolerant battery systems 62 with single or three-branch configurations, but the solution proposed according to the invention can also be used in any multi-branch fault-tolerant battery system 62 in terms of the envisioned structure. The fault-tolerant battery system 62 proposed according to the invention can be used not only in electrically driven vehicles, and especially not only in autonomous vehicles to comply with relevant safety standards, but also in fuel cell vehicles / fuel cell storage systems where the voltage of each fuel cell stack is monitored by a single-cell monitoring loop and fault tolerance is required.

[0045] This invention is not limited to the embodiments described herein and the aspects emphasized in the embodiments. Rather, various modifications that are well known to those skilled in the art can be implemented within the scope of the claims.

Claims

1. A fault-tolerant battery system (62) having branches (28, 84, 86) consisting of individual battery cells (42, 44, 46), the individual battery cells being connected in a series circuit (90), and the branches (28, 84, 86) being connected in a parallel circuit (82), each individual battery cell (42, 44, 46) having a single-cell monitoring loop (54) within the battery module, the single-cell monitoring loop being connected to a battery control unit (30, 32), characterized in that, Redundant additional single-cell monitoring loops (66, 70, 74) are connected to the battery control unit (30, 32) and installed on each of the branches (28, 84, 86), and are activated together with registers (64, 68, 70) for storing analog data or corresponding digital values ​​of the branches (28, 84, 86) in the event of a malfunction in the single-cell monitoring loop (54) inside the battery module.

2. The fault-tolerant battery system (62) according to claim 1, characterized in that, Each branch (28, 84, 86) is equipped with a redundant additional single-pool monitoring loop (66, 70, 74) for all modules (36, 38, 40) in each branch (28, 84, 86).

3. The fault-tolerant battery system (62) according to claim 1, characterized in that, Analog or digital data, particularly the voltage and temperature of the individual cells (42, 44, 46) of the battery in each branch (28, 84, 86), are detected in registers (64, 68, 72) assigned to each branch (28, 84, 86).

4. The fault-tolerant battery system (62) according to claim 3, characterized in that, The registers (64, 68, 72) are integrated circuits or multiplexed devices.

5. The fault-tolerant battery system (62) according to claim 3, characterized in that, The registers (64, 68, 72) include memory space (50.1 to 50.8) corresponding to the number of modules (36, 38, 40) to be monitored in the corresponding branches.

6. The fault-tolerant battery system (62) according to any one of claims 1 to 5, characterized in that, Each of the registers (64, 68, 72) is equipped with a selection switch (76, 78, 80). The selection switch connects the analog or digital data of the branch (28, 84, 86) to the input terminal of the corresponding redundant additional single-pool monitoring loop (66, 70, 74).

7. The fault-tolerant battery system (62) according to claim 6, characterized in that, The selector switches (76, 78, 80) each include a switch level with a number of modules (36, 38, 40) to be monitored corresponding to the number of the corresponding branches (28, 84, 86).

8. The fault-tolerant battery system (62) according to any one of claims 1 to 5, characterized in that, The single-cell monitoring loop (54) inside the battery module is connected to the main battery control unit (30).

9. The fault-tolerant battery system (62) according to claim 6, characterized in that, Each redundant additional single-cell monitoring loop (66, 70, 74) of each branch (28, 84, 86) is connected to the slave battery control unit (32) that drives the selector switches (76, 78, 80).

10. The fault-tolerant battery system (62) according to any one of claims 1 to 5, characterized in that, The registers (64, 68, 72) store the data of the numbers in the branches (28, 84, 86).

11. A method for operating a fault-tolerant battery system (62) according to any one of the preceding claims, comprising the following method steps: a) When the simulated data or the corresponding numerical data of the simulated data measured by the single-cell monitoring circuit (54) inside the battery module in the branch (28, 84, 86) is unreasonable, the redundant additional single-cell monitoring circuit (66, 70, 74) is turned on. b) Measurements of branches (28, 84, 86) via redundant additional single-pool monitoring loops (66, 70, 74) according to a) values / data classified as unreasonable analog or digital, and c) Compare the data / values ​​measured according to a) and b) for explicit error detection.

12. The method according to claim 11, characterized in that, The comparison in step c) is performed within the scope of the comparison using limit values, either exceeding or falling below the threshold.

13. Application of the fault-tolerant battery system (62) according to any one of claims 1 to 10 in an electrically operated vehicle.

14. Application of the fault-tolerant battery system (62) according to any one of claims 1 to 10 in a vehicle driven by a fuel monocell system.

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