Device and method for monitoring temperature of electrical energy store

Abstract

The invention relates to a device for monitoring the temperature of an energy store, which has M subsets, each of which consists of P storage cells, M > = 1 and / or P > = 1, the P storage cells being arranged electrically parallel to one another, and the M subsets being arranged electrically in series. The device is designed to determine M impedance measurements corresponding to the M sets of storage cells and to monitor the temperature of the energy store on the basis of the M impedance measurements.

Description

Technical Field

[0001] The invention relates to an electrical energy store, for example for use in a motor vehicle, and in particular to a method and a corresponding device for monitoring the temperature of different storage cells of an electrical energy store. Background Art

[0002] At least partially electrically driven vehicles have an energy storage device for storing electrical energy for operating the vehicle's electric drive motor. The energy storage device usually has a plurality of individual storage cells, in particular a plurality of round cells, which are arranged in a housing of the energy storage device.

[0003] The service life and / or efficiency of an electrical energy store is often dependent on the temperature and / or temperature management of the individual storage cells of the energy store. Summary of the invention

[0004] The present invention is directed to the technical object of enabling particularly efficient and reliable temperature management of individual storage cell subsets of an electrical energy store, in particular in order to increase the service life and / or efficiency of the energy store.

[0005] This object is achieved by the independent claim. Advantageous embodiments are described in particular in the dependent claims. It should be noted that the additional features of a patent claim that is subordinate to an independent patent claim can form an invention of its own and independent of the combination of all features of the independent patent claim without the features of the independent patent claim or in combination with only part of the features of the independent patent claim, which invention can become the subject of an independent claim, a divisional application or a subsequent application. The same applies to technical teachings described in the specification, which can form inventions independent of the features of the independent patent claim.

[0006] According to one aspect, a device for temperature monitoring of an electrical energy storage device is described, which energy storage device may have M subsets, each subset consisting of P storage cells, where M≥1 and / or P≥1. Typical values ​​for P are between 2 and 6, and / or typical values ​​for M are 50 or more, or 100 or more. The P storage cells may be arranged electrically in parallel with one another. The M subsets may be arranged electrically in series.

[0007] The energy store can have a rated voltage of 60 V or more, or 300 V or more, in particular 800 V or more. The energy store can be designed to store electrical energy for operating a drive motor of a motor vehicle.

[0008] The energy storage device comprises (optionally exactly) R rows of storage cells, each row having (optionally exactly) Q columns of storage cells. In other words, the energy storage device may have a matrix of (optionally exactly) R×Q storage cells and / or storage cell positions. Here, R×Q may be equal to M×P. The rows may extend along a longitudinal axis of the energy storage device, respectively, and the columns may extend along a transverse axis of the energy storage device, wherein the transverse axis is arranged perpendicular to the longitudinal axis. For example, the longitudinal axis may correspond to the longitudinal axis of a vehicle on which the energy storage device is installed, and the transverse axis may correspond to the transverse axis of the vehicle.

[0009] In a preferred example, the storage cell positions of the R rows and Q columns are each occupied by (exactly) one storage cell. In this case, the energy store comprises a total of R×Q storage cells. However, as explained further below, it is advantageously possible for individual storage cell positions to be unoccupied.

[0010] The storage cells can each be cylindrical and / or the storage cells can be round cells. The storage cells can be arranged adjacent to one another in such a way that the storage cells each extend along a vertical axis of the energy storage device (which can correspond to the vertical axis of the vehicle in which the energy storage device is installed). The longitudinal axis, the transverse axis and the vertical axis can correspond to the axes of a Cartesian coordinate system.

[0011] The storage cells and / or storage cell locations (i.e. the locations for the individual storage cells) can be arranged in a honeycomb-like manner in the rows R and columns Q. In this case, (exactly) three storage cells or storage cell locations can each surround (exactly) one cavity. Furthermore, (exactly) six storage cells or storage cell locations can each surround (exactly) another storage cell or (exactly) another storage cell location.

[0012] The energy storage device may have a temperature control system for temperature control, in particular for cooling and / or heating. The temperature control system may have one or more temperature control lines, each of which extends, for example, between two directly adjacent rows of storage cells. A temperature control fluid may be guided through each temperature control line in order to control the temperature of the storage cells abutting against the corresponding temperature control line.

[0013] The device can be designed to determine M impedance measurement values ​​corresponding to the M storage cell subsets. The M (complex) impedance measurement values ​​can be determined for a specific measurement frequency. An impedance measurement value can have a real part and an imaginary part.

[0014] The device can be designed to induce a measuring alternating current at the poles (especially at the terminals) of the energy storage device. Here, the measuring alternating current can have the specific measuring frequency and have a measuring amplitude and a measuring phase. Then, for each of the M storage cell subsets, a measuring alternating voltage caused by the measuring alternating current can be detected at the corresponding storage cell subset, wherein the measuring alternating voltage has a measuring amplitude and a measuring phase.

[0015] The impedance measurement value of the respective storage cell subset can then be determined in a precise manner based on the measured amplitude and the measured phase of the measured alternating current and based on the measured amplitude and the measured phase of the measured alternating voltage.

[0016] The device is also designed to monitor the temperature of the energy storage device based on the M impedance measurement values. The impedance measurement values ​​can be used as indicators for the temperature values ​​of the corresponding storage cell subsets. This enables particularly efficient and precise temperature monitoring.

[0017] The device can be designed to also implement temperature monitoring based on characteristic data (wherein the characteristic data are usually determined experimentally (before use in the device)). These characteristic data can respectively display reference values ​​of the impedance of a storage cell subset for a plurality of different values ​​of the temperature of the storage cell subset. In other words, the characteristic data can display the relationship between the impedance and the temperature of the storage cell subset. This relationship can be used to determine the temperature estimate of each storage cell subset in an efficient and accurate manner and to perform temperature monitoring of the energy storage device.

[0018] The device can be designed to determine corresponding M temperature estimates of the corresponding M storage cell subsets using the characteristic data and based on the M impedance measurement values. For this purpose, the device can be designed to determine, for each of the M storage cell subsets, a reference value corresponding to the impedance measurement value of the corresponding storage cell subset from the characteristic data. The temperature estimate of the corresponding storage cell subset can then be determined from the characteristic data in an accurate manner based on the temperature value associated with the determined reference value (in particular as a temperature value associated with the determined reference value).

[0019] Furthermore, the device can be designed to enable temperature monitoring of the energy storage device in a particularly precise manner based on M temperature estimates corresponding to the M storage cell subsets.

[0020] The device may be designed to identify, based on the M impedance measurements (e.g. based on the determined temperature estimate), a partial subset of the M storage cell subsets having a temperature that deviates from the complementary remaining subset (of the M storage cell subsets). Alternatively, a partial subset of the M storage cell subsets having a measurement that deviates from the complementary remaining subset may be directly identified, so as to thereby identify a corresponding partial subset of the M storage cell subsets having a temperature that deviates from the complementary remaining subset.

[0021] If one or more storage cell subsets are identified, which have a temperature that (significantly) deviates from the remaining complementary subset, this can be an indication of a fault in the energy store, in particular in the temperature control system of the energy store. Measures can then be initiated (for example, outputting a fault message) in order to counteract the fault.

[0022] Therefore, the device can be designed to identify a partial subset of the M storage cell subsets based on the M impedance measurement values, which has a measurement value that deviates from the complementary remaining subset. For this purpose, an average value of the M impedance measurement values ​​can be determined based on the M impedance measurement values. Then, one or more storage cell subsets can be identified, the measurement values ​​of the one or more storage cell subsets deviate from the average value by more than a predefined deviation value (for example, more than a specific percentage and / or more than a specific absolute value), so as to identify a partial subset of the M storage cell subsets, which has a measurement value that deviates from the complementary remaining subset.

[0023] As stated further above, a deviating impedance measurement can be used as an indication of a deviating temperature.The device can therefore be designed to determine that there is a technical problem associated with the temperature control of an identified partial subset of the M storage cell subsets.

[0024] For example, the device can be designed to determine whether the spatial position of the identified partial subset of the M storage cell subsets (in the energy storage device) is correlated with, in particular, consistent with, the spatial position of one or more temperature control pipelines of the temperature control system for temperature control of the energy storage device. In addition, when it is determined that the spatial position of the identified partial subset of the M storage cell subsets is correlated with, in particular, consistent with, the spatial position of one or more temperature control pipelines of the temperature control system, it can be determined that the temperature control system has a defect (for example, one or more at least partially blocked temperature control pipelines).

[0025] In this way, efficient and reliable monitoring of the temperature control system of the energy store can be achieved.

[0026] The device can be designed to determine M impedance frequency curves corresponding to M storage cell subsets. Here, the frequency curves can each include a plurality of impedance measurement values ​​corresponding to a plurality of measurement frequencies (e.g., for 5 or more, or 10 or more measurement frequencies). Then, the temperature monitoring of the energy storage device can be realized in a particularly accurate manner based on the M impedance frequency curves.

[0027] The device can be designed to determine M impedance reference measurement values ​​corresponding to the M storage cell subsets when the energy storage device is in a reference state. The reference state can be, for example, a state in which the M storage cell subsets have the same temperature, or at least a state that can be assumed from the M storage cell subsets having the same temperature. This can be the case after a vehicle (with the energy storage device installed) has been stationary for a relatively long time.

[0028] Although the M subsets of storage cells have the same temperature, the M impedance reference measurement values ​​may differ from each other due to different aging and / or manufacturing tolerances of the individual storage cells.

[0029] The device can also be designed to determine M operating impedance measured values ​​corresponding to the M storage cell subsets when the energy store is in an operating state in which the energy store is currently temperature-controlled.

[0030] The temperature monitoring of the energy storage device in the operating state can then be carried out in a particularly precise manner based on M impedance reference measured values ​​and based on M impedance operating measured values, in particular based on a comparison of M operating measured values ​​with corresponding M reference measured values. For example, M difference values ​​can be determined for the corresponding M storage cell subsets for this purpose. The difference value can be determined based on the difference between the operating measured value and the corresponding reference measured value or can be determined as the difference between the operating measured value and the corresponding reference measured value.

[0031] The device can be designed to identify a partial subset of the M storage cell subsets based on M differences, which has a difference that deviates from the complementary remaining subset. For this purpose, an average value of the M differences can be determined based on the M differences. Then, one or more storage cell subsets can be identified, the difference values ​​of which deviate from the average value by more than a predefined deviation value (for example, more than a certain percentage and / or more than a certain absolute value) in order to identify a partial subset of the M storage cell subsets, which has a difference that deviates from the complementary remaining subset. As already stated above, it can be determined that there is a technical problem related to the temperature control of the identified partial subset of the M storage cell subsets.

[0032] According to a further aspect, a (road) motor vehicle, in particular a car or a truck or a bus or a motorcycle, is described, which comprises a device described in this context for temperature monitoring of a vehicle energy store.

[0033] According to another aspect, a method for temperature monitoring of an electrical energy storage device is described. The energy storage device may have M subsets, each of which consists of P storage cells, where M≥1 and / or P≥1. In this case, the P storage cells may be arranged electrically in parallel with one another. Furthermore, the M subsets may be arranged electrically in series.

[0034] The method comprises determining M (plural) impedance measurement values ​​corresponding to the M storage cell subsets. In addition, the method comprises implementing temperature monitoring of the energy storage device based on the M impedance measurement values.

[0035] According to another aspect, a software (SW) program is described. The SW program can be designed to be executed on a processor (for example on a control unit of a vehicle) and thereby to perform the method described herein.

[0036] According to another aspect, a storage medium is described. The storage medium may include a SW program designed to be executed on a processor and thereby to perform the method described herein.

[0037] It should be noted that the devices and systems described in this article can be used not only alone, but also in combination with other devices and systems described in this article. In addition, any aspects of the devices and systems described in this article can be combined with each other in a variety of ways. In particular, the features of the claims can be combined with each other in a variety of ways. In addition, the features listed in brackets should be understood as optional features. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention is described in more detail below with the aid of examples.

[0039] Figure 1 An exemplary vehicle having an energy storage device for storing electrical energy is shown;

[0040] Figure 2a An exemplary round battery cell is shown;

[0041] Figure 2b An exemplary electrical energy storage device having a plurality of round battery cells is shown;

[0042] Figure 3a An exemplary electrical energy store having a temperature control system is shown;

[0043] Figure 3b An equivalent circuit diagram of an electric energy storage device is shown;

[0044] Figure 4 exemplary characterization data showing a relationship between impedance and temperature of a storage cell or a subset of storage cells; and

[0045] Figure 5 A flow chart of an exemplary method for temperature monitoring of an electrical energy store is shown. DETAILED DESCRIPTION

[0046] As stated at the outset, the present invention is concerned with efficient and reliable temperature monitoring of individual storage cells of an electrical energy storage device. Figure 1 An exemplary vehicle 100 is shown, which has an electrical energy store 110 for storing electrical energy and an electric drive motor 102 driven by electrical energy from the energy store 110. In this case, the energy store 110 is usually accommodated in a housing in the vehicle 100. The vehicle 100 may have a (control and / or monitoring) device 101 for controlling and / or for monitoring the electrical energy store 110.

[0047] The energy storage device 110 includes a plurality of storage cells, in particular circular cells. FIG. 2a shows an exemplary storage cell 200, in particular a circular cell, for the energy storage device 110. The storage cell 200 has a cylindrical shape. A positive contact point 201 and a negative contact point 202 for electrically connecting the storage cell 200 are arranged on the end face of the storage cell 200. The positive contact point 201 can be formed by the end face of the cylindrical storage cell 200. The negative contact point 202 can be formed by a bolt extending from the end face of the storage cell 200. In another example, the polarities of the contact points 201 and 202 can be completely opposite.

[0048] A cell voltage 205 may be present between the two contact points 201, 202 of a storage cell 200. This cell voltage may be detected by a measuring unit (not shown) of the energy store 110. The energy store 110 may be designed to detect the cell voltage 205 of individual storage cells 200 and / or the cell voltage 205 of individual storage cells 200 subsets.

[0049] FIG2 b shows an exemplary electrical energy storage device 110 having a plurality of storage cells 200 which are arranged adjacent to each other (i.e. side by side), in particular such that the contact points 201 , 202 of the individual storage cells 200 are arranged on a common side (the upper side in FIG2 b ). The energy storage device 110 may have, for example, 100 or more storage cells 200 , or 1000 or more storage cells 200 .

[0050] The individual storage cells 200 can be connected to one another in an electrically conductive manner via a cell contact system 210. The cell contact system 210 can, for example, have a frame with connecting wires for electrically contacting the contact points 201, 202 of the individual storage cells 200. The cell contact system 210 can be arranged on one side of the storage cells 200, on which the contact points 201, 202 of the storage cells 200 are also arranged. On the opposite side of the storage cells 200, a housing wall (not shown) of the housing of the energy storage device 110 can be arranged. The opposite housing wall can, for example, be configured to cool the individual storage cells 200.

[0051] like Figure 2b As shown, the (cylindrical) storage cells 200 can be arranged so that the sides of directly adjacent storage cells 200 are in contact (wherein an electrically insulating layer can be arranged between the individual storage cells 200, in particular between storage cells 200 belonging to different storage cell 200 subsets). In this case, the storage cells 200 can be arranged adjacent to each other in a honeycomb-like manner, in particular so that a subset of three storage cells 200 each surrounds a cavity, and / or so that every six storage cells 200 just surround another storage cell 200. In this way, the (cylindrical) storage cells 200 can be arranged in a particularly dense manner. The cylindrical storage cells 200 can be arranged in particular in an arrangement with the highest possible packaging density.

[0052] FIG. 3a shows a top view of an electrical energy storage device 110 which, in the example shown, has Q=24 columns of storage cells 200 and R=16 rows of storage cells 200. Thus, the energy storage device 110 includes 24×16 storage cells. Generally speaking, the electrical energy storage device 110 can have Q columns and R rows of storage cells 200 and thus Q×R storage cells 200. The energy storage device 110 is arranged in a housing 301. The energy storage device can have a first pole 321 (e.g., a positive pole) and a second pole 322 (e.g., a negative pole), which are arranged, for example, on the housing 301, respectively.

[0053] The individual storage cells 200 of the energy storage device 110 can be arranged in an MP configuration, that is, in particular, M subsets 300 can be arranged electrically in series between two poles 321, 322, each subset consisting of P storage cells 200. The P storage cells 200 of a subset 300 are arranged electrically in parallel with each other. Figure 3a In the example shown, P=5 storage cells 200 are connected in parallel. Figure 3b Show Figure 3a 3 b shows an equivalent circuit diagram of an energy store 110 , wherein for simplicity only M=3 subsets 300 connected in series are shown, each subset consisting of P=5 storage cells 200 .

[0054] Figure 3a The energy storage device 110 shown has a temperature control system for controlling the temperature of each storage cell 200, in particular cooling or heating. The temperature control system includes a plurality of temperature control lines 313, which extend between each storage cell 200. The temperature control lines 313 preferably have a corrugated shape and / or a serpentine shape, so that each temperature control line 313 extends at least partially along the side of each round cell 200. For example, the energy storage device 110 may have a temperature control line 313 extending between the storage cells 200 between two rows of storage cells 200. Here, a temperature control line 313 may be provided on both sides of each storage cell 200 (and therefore in each row) respectively. Alternatively, only one-sided cooling of each storage cell 200 may be provided, so that only one temperature control line 131 is provided every other row.

[0055] The temperature control system may also have a supply line 311, via which a temperature control fluid 315 (e.g., a liquid) may be conducted to a first end of each temperature control line 313. The temperature control fluid 315 may then be discharged again from the energy storage device 110 via a discharge line 312 at the opposite second end of each temperature control line 313. It should be noted that the supply line 311 and the discharge line 312 may be arranged on the same (first) side of the energy storage device 110. In this case, the temperature control lines 313 are each connected to one another in pairs on the opposite (second) side and flow through them alternately in opposite directions.

[0056] It may happen that a single thermostatic line 313 is (at least partially) blocked, so that only a reduced amount of thermostatic fluid 315 or no thermostatic fluid at all can be conducted through this thermostatic line 313. As a result, the actual temperature of a storage cell 200 arranged on this thermostatic line 313 may deviate from a target temperature for the storage cell 200, which may lead to an impairment of the service life and / or efficiency of the energy storage device 110.

[0057] Providing a plurality of temperature sensors for a corresponding plurality of storage cells 200 of an energy store 110 is usually associated with a relatively high outlay in terms of costs, installation space, reliability and / or weight.

[0058] The (control) device 101 can be designed to cause the impedance measurement value of the respective subset to be determined for each of the M storage cells 200 subsets of the energy store 110. For this purpose, a measurement alternating current 325 with a specific measurement frequency can be caused at the poles 321, 322 of the energy store 110 (the measurement alternating current is superimposed on the direct current of the energy store 110, such as the charging current or the discharging current). Thus, the impedance measurement value can also be determined during the operation of the energy store 110 and / or the vehicle 100. Thus, temperature monitoring can also be achieved during operation.

[0059] Furthermore, the measured alternating voltage 205 generated at the contact points 201, 202 of the storage cells 200 due to the measured alternating current 325 can be detected for each storage cell 200 subset. Then, the (complex) impedance measurement value of the corresponding storage cell 200 subset 300 at the specific measurement frequency can be determined based on the measured alternating voltage 205 (in particular the amplitude and phase) and the measured alternating current 315 (in particular the amplitude and phase).

[0060] Figure 4 An exemplary characteristic data 400 is shown, which are determined experimentally for an energy store 110, for example. The characteristic data 400 include a plurality of impedance reference values ​​406 for a subset 300 of storage cells 200 of the energy store 110. Impedance reference values ​​406 can be provided for a plurality of different temperatures 408 and / or a plurality of different measuring frequencies 407. Each impedance reference value 406 has a real part 401 and an imaginary part 402.

[0061] FIG. 4 shows different frequency curves 405 of impedance reference values ​​406 for different temperatures 408 of a subset 300 of storage cells 200. Here, the frequency curves 405 each have a plurality of impedance reference values ​​406 for a plurality of different (e.g., for 5 or more or 10 or more) measurement frequencies. As can be seen from FIG. 4 , the individual frequency curves 405 differ significantly from one another, especially at relatively low temperatures 408 of 30° C. or less. Therefore, the impedance measurement value of a subset 300 of storage cells 200 can be used as an indicator of the temperature 408 value for the subset 300 of storage cells 200.

[0062] Thus, the device 101 can be designed to determine (during operation of the energy storage device 110) an impedance measurement value (for a specific measurement frequency) of a specific subset 300 of storage cells 200. This measurement value can then be compared with the characteristic data 400 in order to determine an estimate of the temperature 408 of the subset 300 of storage cells 200. For this purpose, an impedance reference value 406 for the specific measurement frequency 407 from the characteristic data 400 can be taken into account. Different reference values ​​406 are associated with different temperature 408 values. A reference value 406 corresponding to the measurement value (e.g. a reference value 406 closest to the measurement value) can then be identified. An estimate of the temperature 408 of the specific subset 300 of storage cells 200 can then be determined based on the temperature 408 value associated with the identified reference value 406, or an estimate of the temperature of the specific subset of storage cells can be determined as a temperature value associated with the identified reference value.

[0063] Optionally, a frequency curve of the impedance measurement values ​​(e.g., for a series of different measurement frequencies) may be determined for the specific subset 300 of storage cells 200. The determined frequency curve may be compared with reference curves 405 from the characteristic data 400 in order to identify one or more reference curves 405 that are most similar to the determined frequency curve. An estimate of the temperature 408 of the specific subset 300 of storage cells 200 may then be determined in a particularly accurate manner based on the temperature 408 values ​​associated with the identified one or more reference curves 405.

[0064] In a corresponding manner, a temperature 408 estimate may be determined for each of the M subsets 300 of the energy storage 110. In this way, temperature monitoring of the individual storage cells 200 of the energy storage 110 may be achieved in an efficient and reliable manner (without using dedicated temperature sensors for this purpose).

[0065] Thus, a measured value of the impedance, in particular a frequency curve of the impedance, can be determined for each of the M subsets 300 of energy store 110. The M measured values ​​and / or the M frequency curves can be analyzed in order to detect damage to the temperature control system of energy store 110. In particular, it can be detected that a portion of the M measured values ​​and / or frequency curves deviates significantly from the remaining measured values ​​and / or frequency curves (which indicates that the corresponding portion of the M subsets 300 has a significantly different temperature 408).

[0066] It can be checked whether the identified partial subset of the storage cell 200 subset 300 is arranged along the temperature control line 313. If this is the case, it can be inferred that the temperature control line 313 is damaged, in particular blocked. Repairs to the temperature control system can then be initiated (for example, by outputting a prompt to the user of the energy storage device 110).

[0067] The above comparison can be performed in a corresponding manner based on the estimated values ​​of temperature 408 determined for M subsets 300. In this case, a sub-set of subsets 300 of storage cells 200 can be identified which has an estimated value of temperature 408 that deviates significantly from the estimated value of temperature 408 of the remaining subsets 300.

[0068] As stated at the outset, the temperature management of the high-voltage storage device 110 is particularly important for the electric vehicle 100. The operating temperature of the high-voltage storage device 110 influences its service life, its efficiency and / or its self-discharge rate. Battery cooling by means of a temperature control system ensures that the (usually lithium-ion) battery 110 remains within an optimal target temperature range. On very hot or very cold days, the battery 110 of the electric vehicle 100 is thus cooled or heated. For effective battery cooling, it is ensured that the coolant 315 flows substantially uniformly in the corresponding cooling channel 313. In this case, the cell voltage and / or temperature can be continuously monitored by means of monitoring electronics (so-called cell monitoring circuits, or CSC for short). The thermal characteristics can be recorded by means of temperature sensors.

[0069] A monitoring system and / or diagnostic method for cooling channels 315 is described herein, which does not require temperature sensors. The monitoring system 101 and / or diagnostic method 500 here use electrical impedance spectroscopy (EIS for short) of a subset 300 of individual storage cells 200 .

[0070] In order to indirectly determine the cell temperature 408, the AC resistance (ie, impedance) of the individual storage cells 200 subset 300 of the vehicle battery 110 can be measured. In this case, the voltage response 205 of the individual storage cells 200 subset 300 is measured for a defined AC excitation 325 (in terms of frequency and amplitude). Based on this, the measured value of the impedance can be calculated in each case.

[0071] As part of the measurement campaign, an impedance spectrum can be determined as characteristic data 400 , wherein it has been shown that the impedance spectrum has a relatively high temperature sensitivity (in particular for temperatures below 30° C.). Based on characteristic data 400 , individual cooling coils 313 can be diagnosed and / or monitored (with regard to blockages), for example during a heating phase of battery 110 .

[0072] FIG5 shows a flow chart of a (optionally computer-implemented) method 500 for temperature monitoring of an electrical energy storage device 110. The energy storage device 110 may have M subsets, each of which consists of P storage cells, where M≥1 and / or P≥1. The P storage cells are arranged electrically in parallel with each other, and the M subsets are arranged electrically in series. Typical values ​​for P are 2 to 6. Typical values ​​for M are 50 or more, or 100 or more, or 200 or more.

[0073] The method 500 comprises determining 501 M impedance measurement values ​​corresponding to the subset 300 of M storage cells 200. The individual measurement values ​​may here respectively represent a real part 401 and an imaginary part 402 of the impedance. The M impedance measurement values ​​may respectively be determined for one or more measurement frequencies.

[0074] The method 500 further comprises implementing 502 temperature monitoring of the energy storage 110 based on the M impedance measurements. The M impedance measurements can be used as indicators of the temperature 408 of the corresponding subset 300 of the M storage cells 200 (optionally using characteristic data 400 showing a relationship between impedance and temperature 408).

[0075] The measures described in this document allow efficient and precise temperature measurement of individual storage cells 200 or individual storage cell subsets 300 , even without the use of temperature sensors. The measures described can be implemented without increasing the hardware expenditure.

[0076] The present invention is not limited to the embodiments shown. It should be noted in particular that the description and the accompanying drawings are intended only to illustrate by way of example the principles of the proposed methods, devices and systems.

Claims

1. A device (101) for temperature monitoring of an electrical energy storage device (110), the energy storage device having M subsets (300), each subset consisting of P storage cells (200), wherein M≥1 and / or P≥1; the P storage cells (200) are arranged electrically in parallel with each other; the M subsets (300) are arranged electrically in series; wherein: The device (101) is designed to: - determining M impedance measurements corresponding to a subset (300) of M storage cells (200); and - enabling temperature monitoring of the energy storage device (110) based on the M impedance measurement values.

2. The device (101) according to claim 1, wherein: - the device (101) is designed to implement the temperature monitoring also based on characteristic data (400); - the characteristic data (400) respectively displays the impedance reference value (406) of the subset (300) of storage cells (200) for a plurality of different values ​​of the temperature (408) of the subset (300) of storage cells (200); and - The characteristic data (400) are in particular determined experimentally.

3. The device (101) according to claim 2, wherein: The device (101) is designed to: - using the characteristic data (400) and based on the M impedance measurements, determining corresponding M temperature (408) estimates for the subset (300) of M storage cells (200); and - implementing temperature monitoring of the energy storage device (110) based on the M temperature (408) estimation values ​​corresponding to the subset (300) of M storage cells (200).

4. The device (101) according to any one of claims 2 to 3, wherein: The device (101) is designed to, for each subset (300) of M storage cells (200): - determining from the characteristic data (400) a reference value (406) corresponding to the impedance measurement value of the corresponding subset (300) of storage cells (200); and - determining a temperature (408) estimate value of the corresponding subset (300) of storage cells (200) from the characteristic data (400) based on the temperature (408) value associated with the determined reference value (406).

5. The device (101) according to any one of the preceding claims, wherein The device (101) is designed to: - identifying a partial subset of the M storage cell (200) subsets (300) based on the M impedance measurement values, the partial subset having a measurement value that deviates from a complementary remaining subset; and - determining that a technical problem exists in connection with the temperature control of the identified partial subset of the subset (300) of the M storage cells (200).

6. The device (101) according to claim 5, wherein: The device (101) is designed to: - determining an average of the M impedance measurements based on the M impedance measurements; and - identifying one or more subsets (300) of storage cells (200) whose measured values ​​deviate from the average value by more than a predefined deviation value, so as to identify a partial subset of the M subsets (300) of storage cells (200) having measured values ​​that deviate from the complementary remaining subset.

7. The device (101) according to any one of claims 5 to 6, wherein: The device (101) is designed to: - determining whether the spatial position of the identified partial subset of the subset (300) of the M storage cells (200) is correlated with, in particular consistent with, the spatial position of one or more temperature control pipelines (313) of a temperature control system for controlling the temperature of the energy storage device (110); and - If it is determined that the spatial position of the identified partial subset of the subset (300) of the M storage cells (200) is correlated with, in particular consistent with, the spatial position of one or more temperature control pipes (313) of the temperature control system, it is determined that the temperature control system, in particular the one or more temperature control pipes (313) of the temperature control system, has a defect.

8. The device (101) according to any one of the preceding claims, wherein The device (101) is designed to: - causing a measuring alternating current (325) at the poles (321, 322) of the energy storage device (110); wherein the measuring alternating current (325) has a measuring frequency, a measuring amplitude and a measuring phase; and - for each subset (300) of the M storage cells (200), respectively, - detecting a measurement alternating voltage (205) caused by the measurement alternating current (325) at a corresponding subset (300) of storage cells (200); wherein the measurement alternating voltage (205) has a measurement amplitude and a measurement phase; and - determining an impedance measurement value of the corresponding subset (300) of storage cells (200) based on the measured amplitude and the measured phase of the measured alternating current (325) and based on the measured amplitude and the measured phase of the measured alternating voltage (205).

9. The device (101) according to any one of the preceding claims, wherein The device (101) is designed to: - determining M impedance frequency curves corresponding to the subset (300) of M storage cells (200); wherein the frequency curves respectively include a plurality of impedance measurement values ​​corresponding to a plurality of measurement frequencies; and - Temperature monitoring of the energy storage device (110) is achieved based on the M impedance frequency curves.

10. The device (101) according to any of the preceding claims, wherein The device (101) is designed to: - determining M impedance reference measurement values ​​corresponding to a subset (300) of M storage cells (200) when the energy storage device (110) is in a reference state; - determining M impedance operating measurements corresponding to a subset (300) of M storage cells (200) when the energy storage device (110) is in an operating state; and - In the operating state, the temperature of the energy storage device (110) is monitored based on the M impedance reference measurement values ​​and based on the M impedance operating measurement values, in particular based on a comparison of the M operating measurement values ​​with the corresponding M reference measurement values.

11. A method (500) for temperature monitoring of an electrical energy storage device (110), the energy storage device having M subsets (300), each subset consisting of P storage cells (200), wherein M≥1 and / or P≥1; the P storage cells (200) are arranged electrically in parallel with each other; the M subsets (300) are arranged electrically in series; wherein: The method (500) comprises: - determining (501) M impedance measurement values ​​corresponding to the subset (300) of M storage cells (200); and - implementing (502) temperature monitoring of the energy storage device (110) based on the M impedance measurement values.

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