DE102020207865A1 - Battery system and method for operating a battery system - Google Patents

Abstract

The invention relates to a fault-tolerant battery system (10) and a method for its operation. The battery system (10) comprises at least one battery module (18, 20, 22), which is / are combined to form at least one string (12), and a battery control unit (40) for monitoring the at least one battery module (18, 20, 22) ), wherein the at least one battery module (18, 20, 22) has several battery cells (24, 26, 28, 30) connected in series (34) and / or in parallel, and a master battery cell monitoring unit (36) with master Sensors for detecting measured values (61) of the battery cells (24, 26, 28, 30) and of the at least one battery module (18, 20, 22). The at least one battery module (18, 20, 22) also has a slave battery cell monitoring unit (38) with slave sensors for recording measured values (61) of the battery cells (24, 26, 28, 30) and of the at least one battery module (18, 20, 22), the master battery cell monitoring unit (36) having evaluation electronics (67) for evaluating the measured values (61) of the battery cells (24, 26, 28, 30) recorded by the master and / or slave sensors and of the at least one battery module (18, 20, 22).

Description

The invention relates to a battery system, comprising at least one battery module, which is / are combined to form at least one string, and a battery control unit for monitoring the at least one battery module, the at least one battery module having several battery cells connected in series and / or in parallel, and a master -Battery cell monitoring unit with master sensors for recording measured values of the battery cells and the at least one battery module. The invention also relates to a method for operating a battery system proposed according to the invention. The invention also relates to a motor vehicle.

State of the art

In today's electrically powered vehicles, several battery cells are not only connected to one another in series, but also in parallel. This achieves a sufficiently high battery capacity and thus a long vehicle range, but the required power can also be made available. Such battery cells are usually connected in parallel within a battery module, with several battery modules being connected to one another in series in order to achieve the required battery voltage. Each battery module has a battery cell monitoring unit (Cell Supervising Circuit, CSC), which measures the individual battery cell voltages and the temperature (s) in the battery module and forwards it to a higher-level battery control unit (BCU) for further evaluation.

For autonomously operated electric vehicles (Electric Vehicle, EV), special requirements apply, in particular with regard to the driving ability of the vehicle, since such vehicles are not permitted to break down. Depending on the degree of automation, these vehicles must meet a certain security level (Safe Stop Level, SSL). For this purpose, they are classified according to different risk levels (Automotive Safety Integrity Level, ASIL), which is associated with increased demands on the battery design. Less error-prone systems or even fault-tolerant systems can have redundancy, i. H. A duplication of individual subcomponents up to doubling the entire battery system.

Today's fault-tolerant battery systems each include a master and a slave battery control unit as well as master and slave battery cell monitoring units. If a master battery cell monitoring unit, which is connected to the master battery control unit, suspects an error, a slave battery cell monitoring unit corresponding to the master battery cell monitoring unit, which is connected to the slave battery control unit, is switched on and transmits the measured values, for example Voltage and temperature values to the slave battery control unit. This transmits the measured values via a communication bus, such as a CAN bus, to the master battery control unit, which evaluates the measured values and determines the uniqueness of the error allocation, such as sensor or cell errors.

The document WO 2019/211659 A1 describes embodiments of an aircraft monitoring system for an electric or hybrid aircraft. The aircraft monitoring system can be designed so that the electric or hybrid aircraft can meet the certification requirements for a safety risk analysis. The aircraft monitoring system can have various subsystems for monitoring and warning of failures of components, such as, for example, a power source for driving an electric motor, the electric or hybrid aircraft.

The document US 10,189,354 B2 describes a method for operating a battery system with several battery cells and a battery management system for monitoring and controlling the battery cells, the battery management system having a main control device, as well as a first measuring chain and a second measuring chain, each with several measuring chips, which are used for the redundant acquisition of measured data on the battery cells and are each set up to carry out diagnoses and a state of charge equalization of the battery cells. It is provided that the battery system has a control channel via which a hierarchical status of the two measurement chains is determined, with the battery system being switched to a mode of reduced availability in the event of failure of one of the measurement chains and the hierarchy status being set so that the other measurement chain does the detection the measurement data, the diagnoses and the charge balance.

Disclosure of the invention

A battery system is proposed which comprises at least one battery module, which is / are combined to form at least one string, and a battery control unit for monitoring the at least one battery module. In this case, the at least one battery module has a plurality of battery cells that are connected in series and / or in parallel, and a master battery cell monitoring unit with master sensors for recording measured values of the Battery cells and the at least one battery module.

According to the invention, the at least one battery module has a slave battery cell monitoring unit with slave sensors for recording measured values from the battery cells and from the at least one battery module. The master battery cell monitoring unit has evaluation electronics for evaluating the measured values of the battery cells and of the at least one battery module recorded by the master and / or slave sensors.

The measured values recorded by the sensors include, for example, a temperature and a voltage of each individual battery cell and a temperature and a voltage of the entire battery module.

The master battery cell monitoring unit communicates with both the battery control unit and the slave battery cell monitoring unit. As a result, there is consequently no longer any direct connection / control to the slave battery cell monitoring unit. For example, measured values of the battery cells and of the at least one battery module recorded by the slave sensors are transmitted from the slave battery cell monitoring unit to the master battery cell monitoring unit and compared by means of the evaluation electronics with corresponding measured values of the battery cells and of the at least one battery module recorded by the master sensors. Measured values of the battery cells and of the at least one battery module evaluated by the evaluation electronics are transmitted, for example, from the master battery cell monitoring unit to the battery control unit.

The at least one battery module is preferably designed as an asymmetrical battery module, i. H. only the master battery cell monitoring unit has evaluation electronics, while the slave battery cell monitoring unit is designed as a standard component and has no evaluation electronics.

The battery control unit can have, for example, ASIL-D-capable processor architectures that are (multiple) redundant with regard to memory, logic, monitoring and communication. This enables operation without a further / redundant battery control unit.

The battery control unit can also communicate with the slave battery cell monitoring unit. For example, measured values of the battery cells and of the at least one battery module recorded by the slave sensors are transmitted from the slave battery cell monitoring unit to the battery control unit.

The master and slave battery cell monitoring units each have an A / D converter for converting the analog signal values from the sensors into digital signal values. These digital signal values are used as input values both by the evaluation electronics for evaluating the measured values of the battery cells and of the at least one battery module recorded by the master and slave sensors, as well as by the battery control unit for determining further variables, for example the state of charge (SoC) , the state of health (SoH) and the predicted current.

The master battery cell monitoring unit preferably has redundant evaluation electronics. A failure of the evaluation electronics can thus be counteracted by this redundant evaluation electronics.

The battery system proposed according to the invention, in particular designed to be fault-tolerant, is characterized by a structure made up of standard components which, on the one hand, facilitate the most cost-effective production of the fault-tolerant battery system proposed according to the invention and, on the other hand, are extremely simple and inexpensive in terms of the number of components used. In the battery system proposed according to the invention, the series connection within the battery modules comprises at least one battery cell as a 1p arrangement or at least two battery cells connected in parallel as an Xp arrangement.

Furthermore, the fault-tolerant battery system proposed according to the invention is designed in such a way that it has first coupling devices with which battery modules are disconnected from the string and can be bridged via bypass lines which include second coupling devices.

As an alternative to the above-mentioned possible embodiment of the fault-tolerant battery system proposed according to the invention, it can comprise first coupling devices within the individual battery modules, with which individual battery cells or individual battery cell packs, each comprising several battery cells connected in parallel, are switched off within the battery module and incorporated into the second coupling device via a bypass line can be bridged.

• - Erfassen von Messwerten der Batteriezellen sowie des mindestens einen Batteriemoduls durch die Master-Sensoren;
• - Auswerten der von den Master-Sensoren erfassten Messwerte der Batteriezellen sowie des mindestens einen Batteriemoduls;
• - Überprüfen der von den Master-Sensoren erfassten Messwerte der Batteriezellen sowie des mindestens einen Batteriemoduls auf Plausibilität/Fehlerverdacht;
• - Antriggern eines Erfassens von Messwerten der Batteriezellen sowie des mindestens einen Batteriemoduls durch die Slave-Sensoren im Fehlerverdachtsfall oder Fortführen des Erfassens der Messwerte der Batteriezellen sowie des mindestens einen Batteriemoduls durch die Master-Sensoren bei Plausibilität.

The invention also relates to a method for operating a The battery system proposed according to the invention, comprising at least the following method steps:

• - Acquisition of measured values of the battery cells and of the at least one battery module by the master sensors;
• - Evaluation of the measured values of the battery cells and of the at least one battery module recorded by the master sensors;
• - Checking the measured values of the battery cells and of the at least one battery module recorded by the master sensors for plausibility / suspected faults;
• - Triggering of the recording of measured values of the battery cells and the at least one battery module by the slave sensors in the event of a suspected fault or continued recording of the measured values of the battery cells and of the at least one battery module by the master sensors in the event of plausibility.

The measured values of the battery cells and of the at least one battery module recorded by the master sensors are evaluated by comparing these measured values within the at least one battery module. In particular, the measured values for a voltage of the individual battery cells and the measured values for a module temperature are compared with one another. The evaluation of the measured values of the battery cells and of the at least one battery module recorded by the master sensors can be carried out, for example, by means of the evaluation electronics.

If the battery system proposed according to the invention comprises several battery modules, the evaluation of the measured values of the battery modules recorded by the master sensors takes place by comparing these measured values within the battery system. In particular, the measured values for a temperature of the individual battery modules are compared with one another. The method proposed according to the invention is described below on the basis of measured values from the battery cells of a battery module. The procedure can be carried out in the same way for the measured values of the battery modules.

The measured values of the battery cells and of the at least one battery module recorded by the master sensors are then checked for plausibility / suspected faults.

An error is suspected if at least one measured value of at least one of the battery cells recorded by the master sensors deviates significantly from corresponding measured values of the other battery cells of the at least one battery module recorded by the master sensors. The same applies to the measured values of the battery modules.

In this context, two measured values deviate significantly from one another if a difference between the two measured values exceeds a predetermined threshold value. The threshold value is preferably greater than a measurement accuracy of the master sensors. This prevents a defect from being incorrectly recognized by simple measurement errors in the master sensors.

It is plausible if the measured values of the battery cells and of the at least one battery module recorded by the master sensors are approximately the same.

In this context, two measured values are referred to as being approximately the same if a difference between the two measured values falls below the said predetermined threshold value or is equal to the threshold value. This prevents a defect in the said battery cell or in the said battery module from being incorrectly recognized as a result of simple measurement errors in the master sensors.

In this case, the master sensors continuously record plausible or error-free measured values of the battery cells and of the at least one battery module in order to always determine current battery cell status values, such as voltage and temperature. The measured values recorded by the master sensors are transmitted from the master battery cell monitoring unit to the battery control unit to determine further variables, for example the state of charge, the state of aging and the predicted current.

• - Gleichzeitiges Erfassen von Messwerten der Batteriezellen sowie des mindestens einen Batteriemoduls durch die Master- und die Slave-Sensoren;
• - Übertragen der von den Slave-Sensoren erfassten Messwerte von der Slave-Batteriezellenüberwachungseinheit zu der Master-Batteriezellenüberwachungseinheit;
• - Auswerten der gleichzeitig von den Master- und den Slave-Sensoren erfassten Messwerte der Batteriezellen sowie des mindestens einen Batteriemoduls und Überprüfen, ob der Fehlerverdacht bestätigt wurde;
• - Ermitteln der Fehlerart, falls der Fehlerverdacht bestätigt wird oder Fortführen des Erfassens von Messwerten der Batteriezellen sowie des mindestens einen Batteriemoduls durch die Master-Sensoren, falls der Fehlerverdacht nicht bestätigt wird;
• - Übertragen von ausgewerteten Messwerten der Batteriezellen sowie des mindestens einen Batteriemoduls von der Master-Batteriezellenüberwachungseinheit zu der Batteriesteuereinheit.

If a fault is suspected, the slave sensors trigger the acquisition of measured values from the battery cells and from the at least one battery module. In this case, at least the following procedural steps are carried out:

• - Simultaneous acquisition of measured values of the battery cells and of the at least one battery module by the master and slave sensors;
• - Transmitting the measured values recorded by the slave sensors from the slave battery cell monitoring unit to the master battery cell monitoring unit;
• - Evaluation of the measured values of the battery cells and of the at least one battery module recorded simultaneously by the master and slave sensors and checking whether the suspected fault has been confirmed;
• - Determination of the type of error, if the suspected error is confirmed or continued recording of measured values of the battery cells and the at least one battery module by the master Sensors, if the suspicion is not confirmed;
• - Transmission of evaluated measured values of the battery cells and of the at least one battery module from the master battery cell monitoring unit to the battery control unit.

The simultaneous acquisition of measured values of the battery cells and of the at least one battery module by the master and slave sensors can be triggered, for example, by the evaluation electronics of the master battery cell monitoring unit.

Advantageously, only measured values from suspect battery cells and from suspect battery modules are recorded by the slave sensors and transmitted from the slave battery cell monitoring unit to the master battery cell monitoring unit.

The measured values of the battery cells and of the at least one battery module evaluated by the evaluation electronics, i.e. the error-free measured values and the correct measured values, are then transmitted from the master battery monitoring unit to the battery control unit, which the battery control unit uses as input values for determining at least one battery module voltage, a battery pack voltage, a State of charge, an aging state, a predictive current and / or other variables are used.

What is to be understood by error-free and correct measured values becomes clear from the following case distinction.

In the event of an error, i. H. the suspicion of an error was confirmed, a master sensor records a measured value that is too small / large compared to the measured values that are recorded by other master sensors of the master battery cell monitoring unit. The slave battery cell monitoring unit uses the slave sensors to determine measured values of the battery cells of the at least one battery module and transmits the measured values to the master battery cell monitoring unit. By means of the evaluation electronics of the master battery cell monitoring unit, the measured values recorded by the master and slave sensors are evaluated by evaluation electronics. The evaluation is carried out by comparing the measured values recorded by the master and slave sensors.

A cell fault in the said battery cell is detected when the measured value recorded by the master sensors deviates significantly from corresponding measured values recorded by the master sensors of the other battery cells of the at least one battery module, and when that of the slave sensors detected corresponding measured value of said battery cell is approximately equal to the measured value of said battery cell detected by the master sensors. This means that the measured value of said battery cell recorded by the slave sensors also deviates significantly from corresponding measured values recorded by the slave sensors of the other battery cells of the at least one battery module. The measured value of the said battery cell recorded by the master sensors is transmitted to the battery control unit as a correct measured value. A battery management system then initiates appropriate measures.

A fault is detected in at least one master sensor of the master battery cell monitoring unit if the corresponding measured value of said battery cell recorded by the slave sensors deviates significantly from the measured value of said battery cell recorded by the master sensors. In addition to the measured values of the battery cells, which have a plausible / error-free measured value that was recorded by the master sensors, the measured value that was recorded by the slave sensors is now transmitted as a correct measured value to the battery control unit.

The master battery cell monitoring unit not only monitors the measured values recorded by the master sensors, but also the measured values recorded by the slave sensors, whereby the intrinsic fault tolerance of the battery cell monitoring unit is given.

Another error that can occur is an error / failure of an A / D converter of the master or the slave battery cell monitoring unit.

If the A / D converter of the master battery cell monitoring unit fails, all measured values recorded by the slave sensors are only looped through in the master battery cell monitoring unit, since no comparison can be made with the measured values recorded by the master sensors, and to the battery control unit forwarded.

If the A / D converter of the slave battery cell monitoring unit fails, the measured values are forwarded to the battery control unit purely from the master battery cell monitoring unit.

In the event of an A / D converter error, there is no double / multiple error analysis. In all other error cases, such as failure of several sensors in a battery cell monitoring unit, the method described correctly detects a double / multiple error and thus a Fault-tolerant operation without impairing driving ability or range is ensured.

The method proposed according to the invention is carried out by means of a battery system which is largely constructed in a cost-effective manner from standard components. In addition, the method proposed according to the invention enables clear error detection so that, for example, safety standards set for autonomously driving electrically powered vehicles can be met.

The method proposed according to the invention can be implemented as an executable computer program in a control unit of the evaluation electronics. This means that there is no signal evaluation in the battery control unit. Only the further statements in the battery management system based on the "correct" data take place there.

In fuel cell storage systems, too, when the measured values of the individual stacks are monitored by means of a fuel cell monitoring unit, the described structure with the method can be used in fault-tolerant systems.

Finally, the present invention relates to a motor vehicle which comprises a battery system proposed according to the invention and / or which is set up to carry out the method proposed according to the invention.

Advantages of the invention

The solution proposed according to the invention in the form of the fault-tolerant battery system and in the form of the method for operating the fault-tolerant battery system proposed according to the invention enables the use of redundant electronic components to achieve a higher ASIL (Automotive Safety Integrity Level) or a safety standard SSL (Safe Stop Level) that applies to autonomously driving vehicles ). With the solution proposed according to the invention, the stated security levels can be implemented in a cost-effective manner through the use of standard hardware components. The method proposed according to the invention for operating a fault-tolerant battery system enables unambiguous fault detection to be achieved. The method proposed according to the invention can handle not only single but also multiple errors. Battery cell errors or sensor / electronic errors can be clearly identified. With the method proposed according to the invention or with software expansion of the evaluation electronics, early detection of a signal drift is possible and, as a result, there is a predictive diagnostic option for autonomously driving electric vehicles.

Furthermore, the fault-tolerant battery system proposed according to the invention ensures safe operation of an autonomously driving vehicle, which does not stop even if battery cell faults occur, but remains at least partially roadworthy, so that a journey that has already started can be continued and ended even if an error has occurred.

With the solution proposed according to the invention in the form of the fault-tolerant battery system and in the form of the method for operating the fault-tolerant battery system proposed according to the invention, the signals are evaluated in the master battery cell monitoring unit, thus the load on the communication lines between the master battery cell monitoring unit and the battery control unit is significantly reduced. A complete failure of the slave battery cell monitoring unit does not lead to an electrically powered vehicle stopping, since the functions are taken over by the master battery cell monitoring unit. An A / D converter fault in the master battery cell monitoring unit also does not result in the electrically driven vehicle stopping, since measured values are made available by the slave battery cell monitoring unit. An optionally available redundant evaluation electronics of the Mater battery cell monitoring unit ensures full evaluation of the sensor signals in the event of a fault in the evaluation electronics.

In addition, the structure and the method can be used for any battery, regardless of the number of battery cells connected in parallel and the number of battery strings.

Figure list

Embodiments of the invention are explained in more detail with reference to the drawings and the following description.

• 1 einen Aufbau eines einsträngigen Batteriesystems mit parallel und seriell verschalteten Batteriezellen,
• 2 den Aufbau eines fehlertoleranten einsträngigen Batteriesystems in 1p-Anordnung, ohne Kopplungseinrichtung,
• 3 den Aufbau eines fehlertoleranten einsträngigen Batteriesystems in 1p-Anordnung mit Batteriezellenkopplungseinrichtungen,
• 4 ein Batteriemodul mit seriell geschalteten Batteriezellen in 3p-Anordnung mit Batteriezellenkopplungseinrichtung,
• 5 ein Batteriemodul in 1p-Anordnung mit diesem zugeordneten Kopplungseinrichtungen in Haupt- und Umgehungsleitung,
• 6 den Aufbau eines fehlertoleranten einsträngigen Batteriesystems mit einem Batteriemodul zugeordneten Kopplungseinrichtungen in Haupt- und Umgehungsleitung,
• 7 den schematischen Aufbau eines Batteriemoduls eines erfindungsgemäß vorgeschlagenen Batteriesystems und
• 8 ein schematischer Verfahrensablauf des erfindungsgemäß vorgeschlagenen Verfahrens zum Betreiben eines fehlertoleranten Batteriesystems.

Show it:

• 1 a structure of a single-strand battery system with battery cells connected in parallel and in series,
• 2 the construction of a fault-tolerant single-strand battery system in a 1p arrangement, without a coupling device,
• 3 the construction of a fault-tolerant single-strand battery system in a 1p arrangement with battery cell coupling devices,
• 4th a battery module with serially connected battery cells in a 3p arrangement with battery cell coupling device,
• 5 a battery module in 1p arrangement with associated coupling devices in the main and bypass lines,
• 6th the construction of a fault-tolerant single-strand battery system with coupling devices assigned to a battery module in the main and bypass lines,
• 7th the schematic structure of a battery module of a battery system proposed according to the invention and
• 8th a schematic process sequence of the method proposed according to the invention for operating a fault-tolerant battery system.

In the following description of the embodiments of the invention, the same or similar elements are denoted by the same reference numerals, a repeated description of these elements being dispensed with in individual cases. The figures represent the subject matter of the invention only schematically.

1 shows a battery system 10 in which one strand 12th from a number of battery modules 18th , 20th , 22nd with a first line contactor 14th and a second line contactor 16 is provided. From the representation according to 1 it can be seen that each of the battery modules 18th , 20th , 22nd a master battery cell monitoring unit 36 assigned. The battery modules 18th , 20th , 22nd are constructed in such a way that the battery cells 24 , 26th , 28 , 30th in a 12s3p circuit 32 are interconnected. The individual battery modules 18th , 20th , 22nd that are in the strand 12th are connected in series 34 connected with each other. The battery system 10 as shown in 1 includes a battery control unit 40 which both with the first line contactor 14th as well as with the second line contactor 16 is in communication and also with the master battery cell monitoring units 36 of the individual battery modules 18th , 20th , 22nd via a first communication line 42 , such as a CAN bus.

The in 1 battery system shown 10 usually form ten to twelve battery cells 24 , 26th , 28 , 30th a battery module 18th , 20th , 22nd . Are several such battery modules 18th , 20th , 22nd , for example eight to ten battery modules, connected to one another in series, the required battery voltage of 400 V, for example, is achieved. This construction of a single-string battery with one string 12th and a series connection 34 of the individual battery modules 18th , 20th , 22nd is very susceptible to a defect in a battery cell 24 , 26th , 28 , 30th . Falls on such a battery system 10 for example the electronics off, for example the battery control unit 40 or one of the master battery cell monitoring units 36 so can the battery system 10 according to the arrangement in 1 can no longer be operated and the vehicle stops. Fault-tolerant battery systems generally have redundancy in the entire or partial battery system, ie individual battery modules 18th , 20th , 22nd or battery control units 40 and / or master battery cell monitoring units 36 are duplicated, which is very expensive and has disadvantages with regard to the required installation space and the ultimate weight of the battery system 10 brings with it.

Embodiments of the invention

2 shows the structure of a fault-tolerant battery system 10 in 1p arrangement 48 without coupling device.

From the representation according to 2 indicates that the battery system 10 one strand 12th includes. Within the strand 12th that has a first line contactor 14th and a second line contactor 16 is secured, there is a first battery module 18th , a second battery module 20th as well as an nth battery module 22nd . These together form a battery pack 23 . As shown in the illustration 2 It also emerges are within the individual battery modules 18th , 20th , 22nd of the battery pack 23 the battery cells 24 , 26th , 28 , 30th as part of the series connection 34 interconnected. In the 2 The illustration shown is also referred to as a 1p arrangement 48. Each of the battery modules 18th , 20th , 22nd of Battery packs 23 as shown in 2 are a master battery cell monitoring unit 36 with master sensors (not shown here) and evaluation electronics 67 (please refer 7th ) as well as a slave battery cell monitoring unit 38 associated with slave sensors, not shown here. The battery system 10 further comprises a battery control unit 40 on that via a first communication line 42 with the master battery cell monitoring units 36 communicates. The slave battery cell monitoring units 38 communicate via a second communication line 66 , which can be implemented as a CAN bus or signal line, with the corresponding master battery cell monitoring units 36 .

Instead of the in 2 1p arrangement 48 shown, the individual battery modules 18th , 20th , 22nd also in a 2p arrangement or a 3p arrangement 50 , see illustration according to 1 , be constructed. All battery modules 18th , 20th , 22nd of the battery pack 23 as shown in 2 have an identical structure.

The battery control unit 40 The entire battery management system takes over, including determining the state of charge based on measured values 61 (please refer 7th ) of the battery cells 24 , 26th , 28 , 30th as well as the battery modules 18th , 20th , 22nd .

When operating the battery system 10 are the readings 61 of the battery cells 24 , 26th , 28 , 30th as well as the battery modules 18th , 20th , 22nd , such as the measured values 61 for a voltage of the individual battery cells 24 , 26th , 28 , 30th and for a temperature of the individual battery modules 18th , 20th , 22nd , detected by the master sensors. The measured values recorded by the master sensors 61 are made by comparing the measured values of the battery cells 24 , 26th , 28 , 30th inside the battery module 18th , 20th , 22nd evaluated among each other. This determines whether at least one measured value recorded by the master sensors 61 at least one of the battery cells 24 , 26th , 28 , 30th of corresponding measured values 61 from the master sensors of the remaining battery cells 24 , 26th , 28 , 30th of the battery module 18th , 20th , 22nd are recorded, deviates significantly.

In this context, two measured values give way 61 significantly differ if there is a difference between the two measured values 61 exceeds a predetermined threshold. The threshold value is preferably greater than a measurement accuracy of the master sensors. This prevents a defect from being incorrectly recognized by simple measurement errors in the master sensors.

Then the measured values recorded by the master sensors 61 of the battery cells 24 , 26th , 28 , 30th as well as the battery modules 18th , 20th , 22nd Checked for plausibility / suspicion of errors.

Plausibility means that the measured values recorded by the master sensors 61 of the battery cells 24 , 26th , 28 , 30th as well as the battery modules 18th , 20th , 22nd are almost the same.

In this context, two measured values 61 are referred to as being approximately the same if there is a difference between the two measured values 61 falls below said predetermined threshold value or is equal to the threshold value. This prevents simple measurement errors in the master sensors from incorrectly causing a defect in the said battery cell 24 , 26th , 28 , 30th or in said battery module 18th , 20th , 22nd is recognized.

In this case, the master sensors record plausible or error-free measured values 61 of the battery cells 24 , 26th , 28 , 30th as well as the battery modules 18th , 20th , 22nd continuously to determine current battery cell status values, such as voltage and temperature. The measured values recorded by the master sensors 61 are thereby controlled by the master battery cell monitoring unit 36 to the battery control unit 40 to determine further variables, for example the state of charge, the state of aging and the predicted current.

If an error is suspected, ie at least one measured value recorded by the master sensors 61 at least one of the battery cells 24 , 26th , 28 , 30th deviates from corresponding measured values 61 from the master sensors of the remaining battery cells 24 , 26th , 28 , 30th of the battery module 18th , 20th , 22nd are recorded, significantly from, a recording of measured values 61 of the battery cells 24 , 26th , 28 , 30th as well as the battery modules 18th , 20th , 22nd triggered by the slave sensors.

The measured values recorded by the slave sensors 61 of the battery cells 24 , 26th , 28 , 30th as well as the battery modules 18th , 20th , 22nd are controlled by the slave battery cell monitoring unit 38 to the master battery cell monitoring unit 36 transmitted and there by means of the evaluation electronics 67 compared and evaluated.

The one from the evaluation electronics 67 compared and evaluated measured values 61 are considered correct readings 65 (please refer 7th ) and from the master battery cell monitoring unit 36 to the battery control unit 40 to determine other variables, such as the state of charge and the state of aging, for example.

The battery system shown 10 in 2 refers to single-string battery systems for the sake of simplicity 10 . The concept structure described can of course also be used for any number of multiple-string batteries and for battery modules 18th , 20th , 22nd with several battery cells connected in parallel 24 , 26th , 28 , 30th applicable.

3 shows the variant of a first battery module 18th of the battery system 10 .

From the representation according to 3 shows that the first battery module 18th of the battery system 10 the master battery cell monitoring unit 36 as well as the slave battery cell monitoring unit 38 includes. In the first battery module 18th are the battery cells 24 , 26th , 28 , 30th in series connection 34 interconnected. In contrast to the design of the also in series connection 34 switched battery modules 18th , 20th , 22nd according to 2 , are at the in 3 illustrated first battery module 18th in the battery system 10 a main line 52 of the strand 12th first coupling devices 44 intended. Each of the in the first battery module 18th according to the Design variant in 3 battery cell shown 24 , 26th , 28 , 30th is a bypass line 54 assigned, in each of which there is a second coupling device 46 is located.

If one of the battery cells falls 24 , 26th , 28 , 30th of the first battery module 18th according to 3 off, this will be the battery cell 24 , 26th , 28 , 30th respectively assigned first coupling device 44 opened so that the battery cell in question 24 , 26th , 28 , 30th can be switched off. A bypass occurs by closing the second coupling device 46 in the battery cell to be switched off 24 , 26th , 28 , 30th assigned bypass line 54 .

For the sake of completeness, it should be mentioned that in the first battery module 18th of the battery system 10 according to 3 the battery cells 24 , 26th , 28 , 30th are connected in 1p arrangement 48.

4th shows the first battery module 18th of the fault-tolerant battery system 10 with first and second coupling devices 44 , 46 that are in 3p arrangement 50 interconnected battery cells 24 , 26th , 28 , 30th assigned.

In 4th is the first battery module 18th constructed in such a way that individual battery cells interconnected to form 3p packets 24 , 26th , 28 , 30th in series connection 34 are switched, for example twelve battery cell packs. The first battery module 18th according to 4th is constructed in such a way that in front of every 3p arrangement 50 of the individual battery cells 24 , 26th , 28 , 30th the first coupling device 44 in the main line 52 located. The bypass line branches off in front of this 54 from, in which the second coupling device 46 is recorded.

With the variant of the first battery module 18th as shown in 4th is a continued operation of the first battery module 18th also possible if single, in 3p arrangement 50 interconnected battery cells 24 , 26th , 28 , 30th should fail, so that the first battery module can continue to operate 18th by opening and closing the first and second coupling device, respectively 44 , 46 , ie by bypassing the defective battery cell 24 , 26th , 28 , 30th , is possible.

5 shows the first battery module 18th in 1p arrangement 48 with this associated coupling devices 44 , 46 in main and bypass lines 52 , 54 .

From the representation according to 5 is a fault-tolerant battery system 10 its first battery module selected here as an example 18th in series connection 34 interconnected battery cells 24 , 26th , 28 , 30th includes. The first battery module 18th shows the master and slave battery cell monitoring units 36 , 38 , each with the in series connection 34 interconnected battery cells 24 , 26th , 28 , 30th are connected.

How out 5 is located in the main line 52 the first coupling device 44 , in front of, analogous to the variant according to 4th , the bypass line 54 branches off. In this is the second coupling device 46 arranged. For switching off the first battery module 18th from the main line 52 the first coupling device is opened 44 and closing the second coupling device 46 so that a first battery module that has turned out to be defective, for example 18th via the bypass line 54 within the strand 12th of the battery system 10 can be circumvented and continued operation of the fault-tolerant battery system proposed according to the invention 10 is possible.

6th shows a battery system 10 or a first battery module 18th the same, the first and second coupling devices 44 , 46 assigned.

Out 6th shows that the battery system shown there 10 a number of battery cells 24 , 26th , 28 , 30th each in a 3p arrangement 50 are connected in parallel. This in 6th picked out first battery module 18th of the battery system 10 points in the main line 52 a first coupling device 44 on. Before the first coupling device 44 branches off the bypass line 54 from, in which the second coupling device 46 is recorded. The battery system falls 10 , its in 3p arrangement 50 interconnected battery cells 24 , 26th , 28 , 30th in series connection 34 are switched off, the first coupling device 44 opened that in the bypass line 54 lying second coupling device 46 closed and therefore the defective battery module 18th , 20th , 22nd bridged so that in the battery system 10 only the damaged one of the battery modules 18th , 20th , 22nd is switched off and the battery system 10 can continue to operate, albeit with reduced performance. This ensures that the fault-tolerant battery system 10 According to the present invention, continued operation of the autonomously driving electric vehicle is guaranteed, the journey does not need to be interrupted, but can be continued, even if with reduced power and increased duration.

7th shows the schematic structure of a selected first battery module 18th of a battery system proposed according to the invention 10 .

The first battery module 18th has several in series 34 interconnected battery cells 24 , 26th , 28 , 30th , a master battery cell monitoring unit 36 and a slave battery cell monitoring unit 38 on. The master and slave battery cell monitoring units 36 , 38 each has an A / D converter 60 while the master battery cell monitoring unit 36 furthermore evaluation electronics 67 having. The slave battery cell monitoring unit 38 can be designed as a standard component, so that the battery system proposed according to the invention 10 can be set up largely in a cost-effective manner.

The measured values recorded by the master sensors 61 the battery cell 24 , 26th , 28 , 30th as well as the first battery module 18th are analog signal values 62 which is generated by the A / D converter 60 of the master battery cell monitoring unit 36 into digital signal values 64 being transformed.

In the error-free / plausible case, the measured values 61 of the battery cells 24 , 26th , 28 , 30th and the first battery module 18th only recorded by the master sensors and as digital signal values 64 from the master battery cell monitoring unit 36 to the battery control unit 40 (see. 2 ) are transmitted as input values to determine further variables.

If an error is suspected, measured values are recorded 61 of the battery cells 24 , 26th , 28 , 30th and the first battery module 18th triggered by the slave sensors. Present in 7th is the acquisition of measured values 61 by means of a command 68 the evaluation electronics 67 triggered.

The measured values recorded by the slave sensors 61 of the battery cells 24 , 26th , 28 , 30th and the first battery module 18th are also analog signal values 62 which is generated by the A / D converter 60 of the slave battery cell monitoring unit 38 into digital signal values 64 being transformed. The digital signal values recorded by the slave sensors 64 converted measured values 61 of the battery cells 24 , 26th , 28 , 30th and the first battery module 18th are then controlled by the slave battery monitoring unit 38 via the second communication line 66 to the master battery cell monitoring unit 36 transfer. By means of the evaluation electronics 67 the master battery cell monitoring unit 36 the values recorded by the master and slave sensors are converted into digital signal values 64 converted measured values 61 the battery cell 24 , 26th , 28 , 30th as well as the first battery module 18th evaluated.

Only measured values are advantageous 61 of suspect battery cells 24 , 26th , 28 , 30th detected by the slave sensors and by the slave battery cell monitoring unit 38 to the master battery cell monitoring unit 36 transfer.

After evaluation by the evaluation electronics 67 the evaluated measured values, i.e. the correct measured values 65 from the master battery cell monitoring unit 36 via the first communication line 42 to the battery control unit 40 transferred to determine other sizes.

8th shows a schematic process flow 100 of the method proposed according to the invention for operating a fault-tolerant battery system 10 .

According to the method proposed according to the invention, it initially takes place in one step 101 a recording of the measured values 61 of the battery cells 24 , 26th , 28 , 30th and the at least one battery module 18th , 20th , 22nd through the master sensors. The measured values recorded by the master sensors 61 of the battery cells 24 , 26th , 28 , 30th and the at least one battery module 18th , 20th , 22nd are via the A / D converter 60 of the master battery cell monitoring unit 36 of analog signal values 62 into digital signal values 64 converted.

The in digital signal values 64 converted measured values 61 of the battery cells 24 , 26th , 28 , 30th of the at least one battery module 18th , 20th , 22nd are then in one step 102 evaluated. The measured values recorded by the master sensors are thereby used 61 of the battery cells 24 , 26th , 28 , 30th within the at least one battery module 18th , 20th , 22nd compared to each other.

The readings 61 of the battery cells 24 , 26th , 28 , 30th and the at least one battery module 18th , 20th , 22nd are then in one step 103 Checked for plausibility / suspicion of errors. It is checked whether the at least one measured value 61 at least one of the battery cells 24 , 26th , 28 , 30th of corresponding measured values 61 the remaining battery cells 24 , 26th , 28 , 30th of the battery module 18th , 20th , 22nd significantly deviates.

In the case of plausibility, ie the measured values recorded by the master sensors 61 of the battery cells 24 , 26th , 28 , 30th and the at least one battery module 18th , 20th , 22nd are approximately the same, the acquisition of measured values 61 of the battery cells 24 , 26th , 28 , 30th and the at least one battery module 18th , 20th , 22nd by the master sensors to determine current battery cell status values in one step 104 and the digital signal values recorded by the master sensors 64 converted measured values 61 of the battery cells 24 , 26th , 28 , 30th and the at least one battery module 18th , 20th , 22nd are considered correct readings 65 in one step 112 from the master battery cell monitoring unit 36 of the at least one battery module 18th , 20th , 22nd to the battery control unit 40 to determine further variables, for example the state of charge, the state of aging and the predicted current.

If there is a suspicion of an error in the measured values recorded by the master sensors 61 of the battery cells 24 , 26th , 28 , 30th and the at least one battery module 18th , 20th , 22nd , before, ie at least one measured value 61 at least one of the battery cells 24 , 26th , 28 , 30th differs from corresponding measured values 61 of the remaining battery cells 24 , 26th , 28 , 30th of the at least one battery module 18th , 20th , 22nd significantly decreases, a recording of measured values becomes 61 of the battery cells 24 , 26th , 28 , 30th and the at least one battery module 18th , 20th , 22nd triggered by the slave sensors. In this case the battery cells 24 , 26th , 28 , 30th of the at least one battery module 18th , 20th , 22nd in one step 105 by the slave battery cell monitoring unit 38 determined with the slave sensors. At the same time, the battery cells 24 , 26th , 28 , 30th of the battery module 18th , 20th , 22nd in the step 105 by the master battery cell monitoring unit 36 determined with the master sensors. The analog signal values 62 the measured values recorded by the respective sensors 61 are converted into digital signal values 64 converted. The digital signal values recorded by the slave sensors 64 converted measured values 61 of the battery cells 24 , 26th , 28 , 30th and the at least one battery module 18th , 20th , 22nd be in one step 106 from the slave battery cell monitoring unit 38 to the master battery cell monitoring unit 36 transfer.

By means of the evaluation electronics 67 the master battery cell monitoring unit 36 the values recorded by the master and slave sensors are converted into digital signal values 64 converted measured values 61 of the battery cells 24 , 26th , 28 , 30th and the at least one battery module 18th , 20th , 22nd in one step 107 evaluated.

If the suspicion of an error is not confirmed, the recording of measured values is stopped 61 of the battery cells 24 , 26th , 28 , 30th and the at least one battery module 18th , 20th , 22nd by the master sensors to determine current battery cell status values in one step 108 and the digital signal values recorded by the master sensors 64 converted measured values 61 of the battery cells 24 , 26th , 28 , 30th and the at least one battery module 18th , 20th , 22nd are considered correct readings 65 in one step 112 from the master battery cell monitoring unit 36 of the at least one battery module 18th , 20th , 22nd to the battery control unit 40 to determine further variables, for example the state of charge, the state of aging and the predicted current.

If the suspicion of an error is confirmed, the type of error, whether a sensor error or a cell error is present, is determined in one step 109 accomplished.

This is done in one step 110 a cell failure in said battery cell 24 , 26th , 28 , 30th recognized their measured value recorded by the master sensors 61 of corresponding measured values 61 from the master sensors of the remaining battery cells 24 , 26th , 28 , 30th of the at least one battery module 18th , 20th , 22nd are detected, deviates significantly if the corresponding measured value detected by the slave sensors 61 of said battery cell 24 , 26th , 28 , 30th approximately the same as the measured value recorded by the master sensors 61 of said battery cell 24 , 26th , 28 , 30th is. This means that the measured value recorded by the slave sensors 61 of said battery cell 24 , 26th , 28 , 30th of corresponding measured values 61 from the slave sensors of the remaining battery cells 24 , 26th , 28 , 30th of the at least one battery module 18th , 20th , 22nd are recorded, deviates significantly. The measured value recorded by the master sensors 31 of said battery cell 24 , 26th , 28 , 30th is in the step 112 as the correct reading 65 to the battery control unit 40 transfer. A battery management system then initiates appropriate measures.

This is done in one step 111 a fault in at least one master sensor of the master battery cell monitoring unit 36 recognized when the corresponding measured value recorded by the slave sensors 61 of said battery cell 24 , 26th , 28 , 30th of the measured value recorded by the master sensors 61 of said battery cell 24 , 26th , 28 , 30th significantly deviates. In addition to the measured values 61 of the battery cells 24 , 26th , 28 , 30th , which is a plausible / error-free measured value 61 which was detected by the master sensors is in the step 112 now the reading 61 which was recorded by the slave sensors as the correct measured value 65 to the battery control unit 40 transfer.

The in 8th illustrated procedure 100 is the same for the measured values 61 of the battery modules 18th , 20th , 22nd feasible.

The invention is not restricted to the exemplary embodiments described here and the aspects emphasized therein. Rather, a large number of modifications are possible within the range specified by the claims, which are within the scope of expert knowledge.

QUOTES INCLUDED IN THE DESCRIPTION

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

Patent literature cited

• WO 2019/211659 A1 [0005]
• US 10189354 B2 [0006]

Claims (10)

Battery system (10), comprising at least one battery module (18, 20, 22), which is / are combined to form at least one string (12), and a battery control unit (40) for monitoring the at least one battery module (18, 20, 22) ), wherein the at least one battery module (18, 20, 22) has several battery cells (24, 26, 28, 30) connected in series (34) and / or in parallel, and a master battery cell monitoring unit (36) with master Sensors for recording measured values (61) of the battery cells (24, 26, 28, 30) and of the at least one battery module (18, 20, 22), characterized in that the at least one battery module (18, 20, 22) has a Slave battery cell monitoring unit (38) with slave sensors for recording measured values (61) of the battery cells (24, 26, 28, 30) and of the at least one battery module (18, 20, 22), the master battery cell monitoring unit (36) evaluation electronics (67) m evaluating the measured values (61) of the battery cells (24, 26, 28, 30) and of the at least one battery module (18, 20, 22) recorded by the master and / or slave sensors. Battery system (10) Claim 1 , characterized in that the master battery monitoring unit (36) has redundant evaluation electronics (67). Battery system (10) Claim 1 or 2 , characterized in that the series circuit (34) within the at least one battery module (18, 20, 22) has at least one battery cell (24, 26, 28, 30) as a 1p arrangement (48) or at least two battery cells (24 connected in parallel) , 26, 28, 30) as an Xp arrangement. Battery system (10) according to one of the Claims 1 until 3 , characterized in that it has first coupling devices (44) with which battery modules (18, 20, 22) are disconnected from the string (12) and can be bridged with second coupling devices (46) via bypass lines (54). Battery system (10) according to one of the Claims 1 until 4th , characterized in that it has first coupling devices (44) within the battery modules (18, 20, 22) with which battery cells (24, 26, 28, 30) are switched off within the battery module (18, 20, 22) and via bypass lines ( 54), in which second coupling devices (46) are received, can be bridged. Method for operating a battery system (10) according to one of the Claims 1 until 5 comprising at least the following method steps: - Acquisition of measured values (61) of the battery cells (24, 26, 28, 30) and of the at least one battery module (18, 20, 22) by the master sensors; - Evaluation of the measured values (61) of the battery cells (24, 26, 28, 30) recorded by the master sensors and of the at least one battery module (18, 20, 22); - Checking the measured values (61) of the battery cells (24, 26, 28, 30) and of the at least one battery module (18, 20, 22) recorded by the master sensors for plausibility / suspected faults; - Triggering of the acquisition of measured values (61) of the battery cells (24, 26, 28, 30) and of the at least one battery module (18, 20, 22) by the slave sensors in the event of a suspected fault or continued acquisition of the measured values (61) of the battery cells (24, 26, 28, 30) and the at least one battery module (18, 20, 22) by the master sensors if plausible. Procedure according to Claim 6 , characterized in that, if plausible, at least the following process step is carried out: - Transmission of the measured values (61) of the battery cells (24, 26, 28, 30) and of the at least one battery module (18, 20, 22) recorded by the master sensors from the master battery cell monitoring unit (36) to the battery control unit (40). Procedure according to Claim 6 , characterized in that, in the event of a suspected error, at least the following process steps are run: Slave sensors; - Transmitting the measured values (61) of the battery cells (24, 26, 28, 30) recorded by the slave sensors from the slave battery monitoring unit (38) to the master battery cell monitoring unit (36); - Comparing the measured values (61) of the battery cells (24, 26, 28, 30) and of the at least one battery module (18, 20, 22) recorded simultaneously by the master and slave sensors and checking whether the suspected fault has been confirmed; Determination of the type of error if the suspected error is confirmed or continued detection by the master sensors if the suspected error is not confirmed; - Transmission of evaluated measured values (61) of the battery cells (24, 26, 28, 30) and of the at least one battery module (18, 20, 22) from the master battery cell monitoring unit (36) to the battery control unit (40). Procedure according to Claim 8 , characterized in that only measured values (61) from suspect battery cells (24, 26, 28, 30) and from suspect battery modules (18, 20, 22) are recorded by the slave sensors and transferred from the slave battery monitoring unit (38) to the Master battery cell monitoring unit (36) are transmitted. Motor vehicle having a battery system (10) according to one of the Claims 1 until 5 comprises, which with a method according to one of Claims 6 until 9 is operated.

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