Method for detecting an operating state with a separate synchronization signal, battery system, computer program product, and vehicle

Abstract

The invention relates to a method (100) for detecting an operating state (221) of at least one battery cell (3) of a battery system (2) based on at least one time-dependent first measurement parameter (210), which can be detected by a first measuring unit (11), and a time-dependent second measurement parameter (211), which can be detected by a second measuring unit (12), comprising: defining (101) a measurement process (200) for detecting the first measurement parameter (210) by the first measuring unit (11) and the second measurement parameter (211) by the second measuring unit (12), and controlling (102) the second measuring unit (12) to detect the second measurement parameter (211) depending on the measurement process (200). The invention further relates to a computer program product, a battery system (2), and a vehicle (1).

Description

[0001] The invention relates to a method for detecting the operating state of at least one battery cell of a battery system based on at least one time-dependent first measurement parameter, which can be detected by a first measuring unit, and a time-dependent second measurement parameter, which can be detected by a second measuring unit. The invention further relates to a computer program product, a battery system, and a vehicle.

[0002] It is known to measure the impedances of battery cells in battery systems using cables connected to one or more electronic devices. However, this requires considerable effort for cable routing. Furthermore, interference, the driver and / or receiver of the respective interface, jitter, and / or the cable characteristics can influence the measurement signals. Measurement systems within the battery cell or near a cell array, which are coupled to processing units via radio or another connection type, typically need to be synchronized with each other and with a control unit, e.g., the one for generating the excitation signal. This places high demands on the interface to establish and maintain time and frequency synchronization between the individual devices.

[0003] For example, German patent DE 10 2013 215 339 A1 discloses the ability to synchronize multiple sensor control units using a common measurement trigger and measurement data request protocol transmitted via a data bus. However, the transmission speed of the protocol and the accuracy of the measurement synchronization are limited by the data bus. To achieve, for example, synchronization of the frequency and phase of different measurement systems, it is desirable to improve the synchronization process.

[0004] Further monitoring options for batteries are known from the documents DE 10 2017 116 162 A1, EP 2 685 269 A1 and CN 1 16 224 130 A.

[0005] It is an object of the present invention to at least partially overcome the aforementioned disadvantages known from the prior art. In particular, it is an object of the present invention to improve the detection of an operating state in a battery system, preferably with regard to measurement accuracy and / or measurement efficiency.

[0006] The foregoing problem is solved by a method with the features of claim 1, a computer program product with the features of claim 9, a battery system with the features of claim 10, and a vehicle with the features of claim 11. Further features and details of the invention will become apparent from the respective dependent claims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the computer program product, the battery system, and / or the vehicle according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention always includes, or allows for, reciprocal reference.

[0007] According to a first aspect of the invention, a method is provided for detecting the operating state of at least one battery cell of a battery system based on at least one time-dependent first measurement parameter, which can be detected by a first measuring unit, and one time-dependent second measurement parameter, which can be detected by a second measuring unit. The method comprises, in particular in the form of process steps: - Defining a measurement process for acquiring the first measurement parameter by the first measuring unit and the second measurement parameter by the second measuring unit, in particular by a control unit of the battery system, - Controlling the second measuring unit to acquire the second measurement parameter depending on the measurement process, in particular by the control unit, - Output of a separate synchronization signal, in particular for controlling the first and / or second measuring unit, to inform at least the second measuring unit about an initial time for carrying out the measurement process, so that the second measuring unit records the second measurement parameter depending on the initial time, in particular by the control unit, - Controlling the first measuring unit to acquire the first measurement parameter depending on the measurement process, and preferably the initial time, in particular so that the first measuring unit acquires the first measurement parameter depending on the initial time, preferably by the control unit, - Determining the operating state based on the first and second measurement parameters, especially by the control unit.

[0008] The battery system preferably comprises several battery cells. The battery system can be designed for integration into a vehicle. Preferably, the battery system, together with the battery cells, forms a traction battery for powering the vehicle. The operating state of the battery cell can be dependent on time and / or situation. For example, the operating state can depend on the aging of the battery cell and / or the driving situation of the vehicle. Preferably, the battery system comprises several battery cells and / or several secondary measuring units, in particular one secondary measuring unit per battery cell.

[0009] The first and second measurement parameters can each be a current parameter, preferably different ones, e.g., in the form of current and voltage. In particular, the first and second measurement parameters can each comprise a curve of a measured quantity, preferably different ones. For this purpose, the first measurement unit can include a first sensor for acquiring the first measurement parameter, and the second measurement unit can include a second sensor for acquiring the second measurement parameter. Furthermore, the first and / or second measurement unit can include, in particular, independent measurement electronics for executing the measurement process and / or for processing the acquired measurement data.

[0010] When defining the measurement process, a measurement sequence, particularly in the form of a measurement protocol, can be specified. Furthermore, the first and second measurement parameters and / or measurement instructions for the first and second measuring units can be defined. For example, the initial time, a measuring range, and / or excitation parameters, particularly in the form of measurement frequencies and / or measurement amplitudes, can be defined. Additionally, the measurement process can specify which measuring unit should participate in the measurement, for example, if several second measuring units are available. Preferably, all second measuring units are involved in the measurement process.

[0011] The first and second measuring units can be controlled simultaneously or separately. Controlling them can include sending information about the measurement process. For example, the measurement sequence and / or information about a measurement frequency can be sent to both the first and second measuring units. This allows for indirect control of the first and / or second measuring units. For instance, the first measuring unit could independently acquire the first measurement parameter and / or the second measurement parameter, and / or execute the measurement process independently.Furthermore, it is conceivable that when the second measuring unit is activated, a control signal to start the measurement process is sent to the second measuring unit, and / or when the first measuring unit is activated, a control signal to start the measurement process is sent to the first measuring unit. This allows for direct control of the first and / or second measuring unit. It is also conceivable that one or more signals for the measurement process are coupled in when the first and / or second measuring unit is activated. The initial time can be transmitted to the first measuring unit when it is activated. However, it is equally conceivable that the first measuring unit is informed of the initial time via the synchronization signal. The first measuring unit can receive the synchronization signal before or after it is activated.

[0012] The synchronization signal can be output wirelessly or via cable. For example, the synchronization signal can be output as a light or RF signal. The separate design of the synchronization signal can be understood to mean, in particular, that the synchronization signal is sent separately, at least for controlling the second measuring unit to acquire the second measurement parameter, and preferably for controlling the first measuring unit to acquire the first measurement parameter. It can be provided that the synchronization signal is sent to both the first and second measuring units. This allows the first measuring unit to also be informed of the initial time via the synchronization signal. Preferably, the synchronization signal can contain only the information about the initial time and / or constitute the information about the initial time itself.

[0013] The initial time point can be understood as a reference point for the measurement process, based on which the time synchronization of the first and second measurement parameters is established or can be established. The initial time point can include absolute and / or relative time information. For example, the initial time point can define the start of the measurement process. Furthermore, the initial time point can, for example, describe a reference phase for the first and / or second measurement parameter in order to align their phases. For example, the curve of the first and / or second measurement parameter can be shifted according to the initial time point after the first and / or second measurement quantity has been acquired, and / or an excitation signal for acquiring the first and / or second measurement parameter can be adjusted to the initial time point.Thus, the acquisition of the first and / or second measurement parameter can be started and / or modified depending on the initial time.

[0014] Preferably, the first and second measurement signals can be combined to determine the operating state. This determination can be performed using a function that depends on the first and second measurement parameters and the initial time. In particular, this function can include a function for calculating the impedance of the battery cell. When determining the operating state, the first and second measurement parameters can be taken into account based on the initial time.

[0015] Thus, the acquisition of the second measurement parameter by the second measuring unit can be synchronized with the first measurement parameter via the synchronization signal. Within the scope of the present invention, it has been recognized that the complexity of the communication, particularly regarding the information about the initial time, can be reduced for the separate synchronization signal. Simultaneously, this allows for a high response speed, enabling highly accurate synchronization, such as of phase and frequency, even with measuring units located far apart. This allows the determination of the operating state to include a more precise and / or complex evaluation of individual state parameters.

[0016] Furthermore, in a method according to the invention, it can advantageously be provided that the control of the second measuring unit for acquiring the second measurement parameter is carried out via a first communication method and the output of the synchronization signal is carried out via a second communication method. In particular, the first and second communication methods differ. Furthermore, the first and second communication methods can each comprise a communication protocol and / or a communication standard. For example, the first and / or the second communication link can comprise wireless and / or wired data communication. Preferably, the second communication method is optical data communication and / or the first communication method is radio communication, preferably Bluetooth communication.This allows for the selection of a transmission method optimized for the synchronization signal, resulting in a high transmission speed. A low complexity of the synchronization signal may suffice to transmit the information about the initial time to the second measuring unit. Simultaneously, communication can be designed to control the first and second measuring units and / or to determine the operating status, for example, for larger data volumes when transmitting control information and / or the first and / or second measurement parameters.

[0017] In a method according to the invention, the synchronization signal is output by a main control unit, which includes the first measuring unit. The first measuring unit acquires the first measurement parameter as a function of the output of the synchronization signal. The second measuring unit can be integrated into the battery cell or arranged on the battery cell. In particular, the second measuring unit can be part of a decentralized control unit, e.g., with a microcontroller and / or an analog-to-digital converter. Preferably, the main control unit and the first measuring unit can be arranged at an input and / or output of a supply line of the battery system. The main control unit can have a central circuit board on which a processing unit for determining the operating state and / or the first measuring unit are arranged.In particular, the main control unit and / or the control unit can form a battery management system. The processing unit can be located directly adjacent to the first measuring unit and / or be in electrically conductive connection with the first measuring unit. Preferably, the control of the first measuring unit for acquiring the first measurement parameter can be performed in parallel with the output of the separate synchronization signal. This eliminates the need, for example, for the first measuring unit to receive and process the synchronization signal. Thus, by ensuring the proximity and / or a low-loss or lossless connection of the first measuring unit to the main control unit, it can be guaranteed that the first measurement parameter is acquired as a function of the initial time.

[0018] Furthermore, in a method according to the invention, it can advantageously be provided that the first measurement parameter is a current across a supply line of the battery system and the second measurement parameter is a local voltage across the battery cell. The current can, for example, be detected as a voltage across a resistor, in particular a shunt resistor. Preferably, the resistor can be part of the main processing unit. The local voltage across the battery cell can comprise a voltage between an anode and a cathode of the battery cell. In particular, the second measurement parameter can be detected in a predefined frequency range, e.g., between 0 and 10 kHz. This allows the operating state of the battery cell to be advantageously determined.

[0019] Furthermore, in a method according to the invention, it is conceivable that the synchronization signal is an optical signal, wherein a light source is controlled to output the synchronization signal. Thus, the output of the synchronization signal can be optical and / or optoelectronic. The light source can, for example, comprise an LED. Advantageously, the light source can be part of the main control unit. The optical signal can be output to the second measuring unit via an optical conductor. For example, the control unit and / or the main control unit can be connected to the second measuring unit via an optical fiber, in particular in the form of a glass fiber and / or a plastic fiber. Furthermore, the battery cell can have an optical window through which the optical signal can be transmitted.The window allows the interior of the battery cell to be sealed even during optical transmission of the synchronization signal. The optical signal enables the information about the initial time to be transmitted with minimal loss, and in particular without interference, quickly and cost-effectively.

[0020] Furthermore, in a method according to the invention, it is conceivable that the synchronization signal comprises a pulsed square wave signal, in particular wherein the initial time is detected by the second measuring unit based on the pulse. For example, the beginning of a pulse of the square wave signal can define the initial time. For example, a square wave edge can be detectable by the second measuring unit in order to detect the initial time. Furthermore, the second measuring unit can be controlled by the square wave signal, in particular by an amplitude of the square wave signal, for the purpose of aligning a frequency generation. Thus, the information about the initial time can be transmitted to the second measuring unit in a simple manner, e.g., by optical transmission.

[0021] Furthermore, in a method according to the invention, it is conceivable that a measurement frequency is defined as a function of a pulse of the synchronization signal for acquiring the first and / or second measurement parameter. The pulse can thus form a reference for phase and / or frequency determination. For example, particularly by the second measuring unit and / or the control unit, an excitation signal with a measurement frequency can be output in the form of an excitation frequency for acquiring the second measurement parameter. The excitation frequency can thus be defined, in particular, as a function of the synchronization signal. The synchronization signal can preferably include information about the measurement frequency in addition to information about the initial time. For example, the synchronization signal can include the measurement frequency and / or a clock frequency for calculating the measurement frequency.In particular, it is conceivable that a frequency standard is transmitted via the pulse of the synchronization signal. Depending on the synchronization signal, frequency standards can be synchronized to, for example, compensate for a phase drift between the excitation signal and the second measurement parameter, and / or to determine and / or minimize a frequency of the second measurement parameter that deviates from the frequency of the excitation signal. For example, the first and / or second measurement unit can adjust its own clock and / or sampling frequency, and / or, for example, adjust filter settings based on the pulsed synchronization signal. Furthermore, it is conceivable that when determining the operating state, especially by impedance spectroscopy, a time difference between the second measurement parameter and the excitation signal is determined. Based on this time difference, a phase can be determined at different excitation frequencies.Thus, the excitation signal can be advantageously improved with regard to the determination of the operating state by the synchronization signal.

[0022] Furthermore, in a method according to the invention, it is conceivable that impedance spectroscopy is performed to determine the operating state based on the first and second measurement parameters, in particular wherein at least one state parameter in the form of a state of charge of the battery cell, a health status of the battery cell, and / or a temperature of the battery cell is determined to identify the operating state during impedance spectroscopy. The impedance of the battery cell can be determined based on the first and second measurement parameters, preferably frequency-dependent. The operating state can be identified based on the impedance. In particular, the state parameter of the operating state can be determined, and especially calculated, as a function of the first and second measurement parameters. The state of charge can include a residual storage of the charging energy of the battery cell.The amplitude of the first and / or second measurement parameter and / or a signal derived from the first and second measurement parameters can, in particular, serve as an indicator of the temperature, the battery's health, and / or the state of charge. For example, an increase in the battery cell's temperature can reduce its internal resistance. This temperature increase can be caused, for instance, by an increase in the ambient temperature and / or by increased stress on the battery cell, such as during charging and / or driving. Furthermore, the internal resistance of the battery cell can increase with a decreasing battery health and / or state of charge. This can be due, for example, to the vehicle's and / or battery system's operating history.

[0023] Furthermore, in a method according to the invention, it is conceivable that the battery system comprises several battery cells, wherein the second measurement parameter is acquired, and in particular measured, at each of the battery cells, particularly as a function of the synchronization signal. The synchronization signal can be sent simultaneously to several second measurement units. For example, the synchronization signal can be distributed across several optical fibers. Furthermore, a decentralized control unit can be arranged at each of the battery cells. It is also conceivable that the second measurement unit acquires a second measurement parameter for all or a plurality of the battery cells. For this purpose, the second measurement unit can be integrated into one of the battery cells and connected to other battery cells via a cable connection. In particular, the second measurement unit can be connected to the respective anodes and cathodes.In particular, the second measuring unit can be implemented as a remote system. By recording the second measurement parameter at each of the battery cells, the operating status of the entire battery system can be determined.

[0024] According to a further aspect of the invention, a computer program product is provided. The computer program product comprises instructions which, when executed by a control unit, cause the control unit to execute a method according to the invention.

[0025] Thus, a computer program product according to the invention offers the same advantages as those already described in detail with reference to a method according to the invention. The method can, in particular, be a computer-implemented method. The computer program product can be implemented as computer-readable instruction code. Furthermore, the computer program product can be stored on a computer-readable storage medium, such as a data disk, a removable drive, volatile or non-volatile memory, or an embedded memory / processor. Furthermore, the computer program product can be made available or provided in a network, such as the Internet, from which it can be downloaded or executed online by a user as needed. The computer program product can be implemented using software as well as one or more special electronic circuits, i.e.,It can be implemented in hardware or in any hybrid form, i.e., using software components and hardware components.

[0026] According to a further aspect of the invention, a battery system, particularly for a vehicle, is provided. The battery system comprises several battery cells and a control unit for carrying out a method according to the invention for detecting an operating state of at least one of the battery cells.

[0027] Thus, a battery system according to the invention offers the same advantages as those already described in detail with reference to a method and / or a computer program product according to the invention. The battery cells can preferably form a traction battery for powering the vehicle.

[0028] According to another aspect of the invention, a vehicle is provided. The vehicle has a battery system according to the invention.

[0029] Thus, a vehicle according to the invention offers the same advantages as those already described in detail with reference to a method, a computer program product, and / or a battery system according to the invention. The vehicle can preferably be a motor vehicle, e.g., an electric vehicle. The control unit can comprise a processor and / or a microprocessor. Furthermore, the control unit can be at least partially or completely integrated into a central control unit of the vehicle and / or the battery system. However, it is also conceivable that the control unit is at least partially or completely integrated into one or more decentralized control units.

[0030] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can be essential to the invention individually or in any combination. The drawings schematically show: Fig. 1 a vehicle according to the invention with a battery system according to the invention, Fig. 2. a process of an inventive method for detecting an operating state of at least one battery cell of the battery system, Fig. 3 a first and second measurement parameter with an initial time point, and Fig. 4 the battery system with multiple battery cells, and Fig. 5 an alternative design of the battery system.

[0031] In the following description of some embodiments of the invention, the same reference numerals are used for the same technical features even in different embodiments.

[0032] Fig. Figure 1 shows a vehicle 1 according to the invention with a battery system 2 according to the invention in a first embodiment. The battery system 2 comprises several battery cells 3. Furthermore, the battery system 2 includes a control unit 10 for carrying out a method 100 according to the invention for detecting an operating state 221 of at least one battery cell 3, here several battery cells 3. For this purpose, for example, a computer program product can be provided which includes commands which, when executed by the control unit 10, cause the control unit 10 to execute the method 100.

[0033] As in Fig. As shown in Figure 4, the detection of the operating state 221 of the battery cells 3 in method 100 is carried out on the basis of at least one time-dependent first measurement parameter 210, which can be detected by a first measuring unit 11, and one time-dependent second measurement parameter 211 for each battery cell 3, which can be detected by a second measuring unit 12. As shown in Fig. As shown in Figure 4, each of the battery cells 3 can have a second measuring unit 12. However, it is also conceivable that a second measuring unit 12 monitors several or all of the battery cells 3. The first measuring parameter 210 is a current on a supply line 4 of the battery system 2, and the second measuring parameter 211 is a local voltage at the respective battery cell 3.

[0034] In procedure 100, as in Fig. As shown in Figure 2, a measurement process 200 is first defined 101 for the acquisition of the first measurement parameter 210 by the first measurement unit 11 and the respective second measurement parameter 211 by each of the second measurement units 12. Depending on the measurement process 200, the second measurement units 12 are controlled 102 to acquire the second measurement parameter 211, and the first measurement unit 11 is controlled 104 to acquire the first measurement parameter 210. Furthermore, a separate synchronization signal 220 is output 103 to inform at least the second measurement units 12 about an initial time 222 for carrying out the measurement process 200, so that the second measurement units 12 acquire the second measurement parameter 211 depending on the initial time 222. Fig. Figure 3 shows the progression of the first and second measurement parameters 210, 211 against a time t. The initial time 222 is also taken into account when the first measurement unit 11 is activated. Thus, the initial time 222 can, for example, define the start of the measurement process 200 and / or a time shift of the second measurement parameter 211. Furthermore, it can be provided that a measurement frequency is defined as a function of a pulse of the synchronization signal 220. Additionally, the second measurement units 12 preferably output an excitation signal with an excitation frequency that is defined as a function of the synchronization signal 220 to acquire the second measurement parameter 211.

[0035] As in Fig. As shown in Figure 4, the second measuring units 12 are controlled 102 for acquiring the respective second measurement parameter 211 via a first communication method 12.1, and the output 103 of the synchronization signal 220 is via a second communication method 12.2. The output 103 of the synchronization signal 220 is performed by a main control unit 10.1, which includes the first measuring unit 11. This allows the first measuring unit 11 to acquire the first measurement parameter 210 depending on the output 103 of the synchronization signal 220, e.g., simultaneously with the output 103 of the synchronization signal 220. Preferably, the synchronization signal 220 is an optical signal. A light source 13 can be controlled to output 103 of the synchronization signal 220. Furthermore, the synchronization signal 220 can include a pulsed square wave signal, so that the initial time 222 is detected by the second measuring units 12 based on the pulse.

[0036] Based on the first and second measurement parameters 210, 211, the operating state 221 is then determined by impedance spectroscopy 201 using the first and second measurement parameters 210, 211. In particular, at least one state parameter 223, preferably three state parameters 223, in the form of a state of charge of the battery cell 3, a health status of the battery cell 3 and / or a temperature of the battery cell 3, is determined during the impedance spectroscopy 201.

[0037] In Fig.Figure 5 further shows an alternative embodiment of a battery system 2 according to the invention. Here, the control unit 10 with the light source 13 is designed separately from the first measuring unit 11. A separate synchronization signal 220 is sent by the control unit 10 to inform the first measuring unit 11 and the second measuring units 12, so that the first measuring unit 11 acquires the first measurement parameter 210 and the second measuring units 12 acquire the second measurement parameter 211 depending on the initial time 222 transmitted by the synchronization signal 220.

[0038] The preceding explanation of the embodiments describes the present invention solely by way of examples. Naturally, individual features of the embodiments can be freely combined with one another, provided this is technically feasible, within the scope of protection defined by the claims, without departing from the scope of the present invention. Reference symbol list 1 vehicle 2 battery system 3 battery cells 4 Supply line 10 Control unit 10.1 Main control unit 11 first unit of measurement 12 second measuring unit 12.1 First form of communication 12.2 second type of communication 13 Light source 210 first measurement parameter 211 second measurement parameter 100 procedures 101 Defining 200 102 Addressing 12 103 Spending out of 220 104 Targeting 11 105 Determining 221 200 Measurement process 201 Impedance spectroscopy 220 synchronization signal 221 Operating status 222 initial time 223 State parameters

Claims

[1] Method (100) for detecting an operating state (221) of at least one battery cell (3) of a battery system (2) by means of at least one time-dependent first measurement parameter (210) detectable by a first measuring unit (11) and a time-dependent second measurement parameter (211) detectable by a second measuring unit (12), comprising: - Defining (101) a measurement process (200) for the acquisition of the first measurement parameter (210) by the first measuring unit (11) and the second measurement parameter (211) by the second measuring unit (12), - Controlling (102) the second measuring unit (12) to acquire the second measurement parameter (211) depending on the measurement process (200), - Output (103) of a separate synchronization signal (220) to inform at least the second measuring unit (12) about an initial time (222) for carrying out the measurement process (200), so that the second measuring unit (12) records the second measurement parameter (211) depending on the initial time (222), - Controlling (104) the first measuring unit (11) to acquire the first measurement parameter (210) depending on the measurement process (200), - Determining (105) the operating state (221) based on the first and second measurement parameters (210, 211), wherein the output (102) of the synchronization signal (220) is performed by a main control unit (10.1) which has the first measurement unit (11), wherein the first measurement unit (11) detects the first measurement parameter (210) as a function of the output (103) of the synchronization signal (220). [2] Method (100) according to claim 1, characterized by, that the control (102) of the second measuring unit (12) to acquire the second measuring parameter (211) is carried out via a first communication type (12.1) and the output (103) of the synchronization signal (220) is carried out via a second communication type (12.2). [3] Method (100) according to any one of the preceding claims, characterized by , that the first measurement parameter (210) is a current at a supply line (4) of the battery system (2) and the second measurement parameter (211) is a local voltage at the battery cell (3). [4] Method (100) according to any one of the preceding claims, characterized by , that the synchronization signal (220) is an optical signal, wherein a light source (13) is controlled to output (103) the synchronization signal (220). [5] Method (100) according to any one of the preceding claims, characterized by, that the synchronization signal (220) comprises a pulsed rectangular signal, wherein the initial time (222) is detected by the second measuring unit (12) based on the pulse. [6] Method (100) according to any one of the preceding claims, characterized by , that to capture the first and / or second measurement parameter (210, 211) a measurement frequency is defined as a function of a pulse of the synchronization signal (220). [7] Method (100) according to any one of the preceding claims, characterized by , that to determine (105) the operating state (221) an impedance spectroscopy (201) is performed on the basis of the first and second measurement parameters (210, 211), wherein to detect the operating state (221) in the impedance spectroscopy (201) at least one state parameter (223) in the form of a state of charge of the battery cell (3), a state of health of the battery cell (3) and / or a temperature of the battery cell (3) is determined. [8] Method (100) according to any one of the preceding claims, characterized by , that the battery system (2) comprises several battery cells (3), wherein the second measurement parameter (211) is recorded at each of the battery cells (3) depending on the synchronization signal (220). [9] Computer program product comprising instructions which, when executed by a control unit (10), cause the control unit (10) to execute a method (100) according to any of the preceding claims. [10] Battery system (2) comprising several battery cells (3) and a control unit (10) for performing a method (100) according to any one of claims 1 to 8 for detecting an operating state (221) of at least one of the battery cells (3). [11] Vehicle (1) comprising a battery system (2) according to the preceding claim.

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