Method for aligning data from a first control unit with data from a second control unit to determine an accurate prediction value

Abstract

The invention relates to a method for aligning data of a first control unit for controlling an electrical energy storage cell having a plurality of electrochemical energy storage devices with a second control unit in order to determine an exact prediction value.

Description

Technical Field

[0001] The invention relates to a method for aligning data of a first control unit for controlling an electrical energy storage cell having a plurality of electrochemical energy storage devices with a second control unit for determining an exact prediction value, a device for operating an electrical energy storage cell and the use of the method. Background Art

[0002] In the software-program state of the battery management system (BMS) of the current battery control unit (BCU), in addition to the functions for operating the battery, the relevant initial parameterization (Erst-Bedatung) is also included. The data involves threshold values ​​for current or temperature, parameters of the battery model, various characteristic curves, characteristic curve groups, factors (Factor). Because their "historical characteristics" also play an important role in the accurate description of the state of the battery, the parameterization of the electrochemical model is extremely expensive. The data is based in particular on extensive laboratory measurements and vehicle measurements, which take into account different aging states and aging methods in order to be able to predict the state of charge (SoC) and therefore the vehicle's effective range as accurately as possible. The data required for this is now only stored incompletely in the battery controller, for example, factors are used instead of the required characteristic curve group for simplicity, because the huge amount of data in the battery controller memory takes up too much storage space. However, this leads to inaccurate predicted vehicle effective range.

[0003] Document CN 104816813 discloses a battery management redundant control system for marine lithium battery packs. The battery management redundant control system includes a master control device, a slave control device, a standby master control device, a battery pack module, a wireless ZIGBEE redundant module, a host computer background monitoring module and an independent line redundant module. When the bus is fault-free, the master controller communicates with the slave controller through the bus. The master controller and the slave controller communicate through messages during operation; when the bus is fault-free, the master control device is connected to the slave control device through the bus in standby mode. In the event of a bus failure, the ZIGBEE radio redundant module collects key parameters of the battery module status and uploads the collected data to the master controller or the master controller in standby mode. The host computer background monitoring module is used to monitor battery parameters and download control instructions, and the independent line redundant module is used to directly control or emergency control the battery pack module through the host computer background monitoring module.

[0004] Document DE 10 2013 209 443 A1 discloses a method for authenticating measurement data of a battery, the battery comprising at least one battery module with an associated module controller and a central controller, the method comprising the following steps: a) acquiring measurement data of a battery cell by means of the module controller; b) obtaining at least one additional information carrier provided for authenticating the measurement data by means of the module controller; c) transmitting the measurement data and the additional information carrier from the module controller to the central controller; d) verifying the measurement data by means of the central controller based on the additional information carrier. In addition, a data structure, a computer program and a battery management system, each of which is provided for executing the method, are described, as well as a battery and a motor vehicle, the drive system of which is connected to such a battery. Summary of the invention

[0005] The object of the present invention is to further improve the prior art. This object is achieved by a method according to the present invention for aligning data of a first control unit for controlling an electrical energy storage cell having a plurality of electrochemical energy storage devices with a second control unit for determining an exact prediction value.

[0006] The method according to the invention for aligning data of a first control unit for controlling an electrical energy storage unit having a plurality of electrochemical energy storage devices with a second control unit for determining a precise prediction value advantageously comprises the following steps:

[0007] a) providing a plurality of data of an electrochemical model of the electrical energy storage cell in groups for different aging stages of the electrical energy storage cell by means of a memory of the second control unit;

[0008] b) providing at least one of the data sets by means of a memory of the first control unit;

[0009] c) detecting a first voltage variable representing a voltage of the electrochemical energy store;

[0010] d) forming an average value of the acquired first voltage parameter;

[0011] e) wirelessly aligning at least one data set of the memory of the first control unit with a data set of the memory of the second control unit if a voltage difference between the formed mean value of the detected first voltage variable and a model voltage variable calculated with the aid of a data set provided by the memory of the first control unit exceeds a predetermined threshold value.

[0012] In this way, data of an electrochemical model, for example battery model parameters, can be provided by means of the memory of the second control unit, thereby making it possible to describe very accurately different degrees of aging of the battery. The data are stored in the memory of the second control unit, for example in the cloud, and are assigned to the memory of the first control unit under certain conditions. Advantageously, the memory of the control unit does not need to be expanded, only a wireless data connection to the cloud needs to be integrated.

[0013] During step c), the voltage of the electrochemical energy storage device should not change (highly) dynamically, since this leads to increased measurement inaccuracies in the voltage value. In electrically driven vehicles with electrical energy storage cells, the conditions for recording the voltage are optimal when driving at a constant speed.

[0014] An electrical energy storage unit within the meaning of the present invention can be an energy storage unit with a plurality of electrochemical energy storage devices, from which electrical energy can either be drawn or to which electrical energy can be supplied and from which electrical energy can be drawn. The electrical energy storage device is designed as a charge storage device and / or as a magnetic energy storage device and / or as an electrochemical energy storage device. The electrochemical energy storage device is in particular a rechargeable battery or accumulator.

[0015] Further advantageous embodiments are the subject matter of the preferred exemplary embodiments.

[0016] The method according to the present invention also comprises the following steps:

[0017] f) detecting a second voltage variable representing the voltage of the electrochemical energy store;

[0018] g) forming an average value of the acquired second voltage parameter;

[0019] h) Generating a signal as a function of a voltage difference between the formed mean value of the detected second voltage variable and a model voltage variable calculated with the aid of the aligned data set.

[0020] By means of comparative measurements using steps f) to h), it can be determined, for example, in a subsequent driving cycle, whether, after the calibration data, there is still a deviation between the formed mean value of the acquired second voltage variable and the model voltage variable calculated with the aid of the calibration data set. This makes it possible to detect a fault in the electrical energy storage unit at an early stage. If no relevant deviation is detected, the electrical energy storage unit can be operated further with the calibration data set.

[0021] Advantageously, the generated signal is a fault signal if the voltage difference exceeds a predetermined threshold value. If a deviation occurs between the formed mean value of the acquired second voltage variable and the model voltage variable calculated with the aid of the adjusted data set that exceeds a predetermined threshold value, the electrical energy storage unit appears to be faulty. The fault can be indicated to a user of the electrical energy storage unit, for example a driver of an electrically driven vehicle with the electrical energy storage unit, by means of an electrical, optical, acoustic and / or haptic fault signal, so that the electrical energy storage unit can be taken to a workshop for inspection.

[0022] The method according to the present invention also comprises the following steps:

[0023] c.1) comparing the determined usage variable representing the cyclic aging and / or calendar aging of the electrical energy storage cell and / or the electrochemical energy storage with a predetermined threshold value; and / or

[0024] c.2) Check whether the electrical energy storage unit works without fault;

[0025] c.3) If the determined usage variable exceeds a predetermined threshold value and / or the electrical energy storage unit operates without error, step c) is carried out.

[0026] Since the battery cells of the electrochemical energy storage system do not age suddenly, it is sufficient to carry out the comparative measurement according to step c) after a certain number of trips of the electrically driven vehicle with the electrical energy storage unit, for example after 20 trips in each case, and / or after a predetermined period of time, for example after two weeks. Thus, both cyclic aging and calendar aging are also taken into account.

[0027] The method according to the present invention also comprises the following steps:

[0028] d.1) Discard abnormal values ​​of the collected voltage parameters.

[0029] The electrical energy storage unit of the electric vehicle consists of about 100 electrochemical energy storage devices connected in series and / or in parallel. All electrical voltage parameters representing the voltage of the individual electrochemical energy storage devices are measured, for example, by means of voltage sensors. After all voltage parameters are present, it is checked whether there are voltage anomalies, since these voltage anomalies are not recorded in the formation of the average value of the electrochemical energy storage device. This enables more accurate prediction values.

[0030] The method according to the present invention also comprises the following steps:

[0031] d.2) comparing the dispersion degree of the collected voltage parameter with a predetermined threshold value;

[0032] d.3) If the dispersion level does not exceed a predetermined threshold, execute step d).

[0033] If the dispersion of the voltage variable exceeds a predetermined threshold value, then a charge state equalization (balancing) is required between the electrochemical energy stores. This check allows a correct comparison with the calculated value of the model voltage variable, thereby allowing a more precise prediction value to be achieved.

[0034] The method according to the present invention also comprises the following steps:

[0035] e.1) checking the current operating state of the electrical energy storage unit;

[0036] e.2) If the electrical energy storage unit is out of service, step e) is carried out.

[0037] Advantageously, at least one data set of the memory of the first control unit is aligned with a data set of the memory of the second control unit if the electrical energy storage unit is shut down, for example directly after the end of a journey of the electrically drivable vehicle.

[0038] Furthermore, if data for different types of electrical energy storage cells are located in the memory of the second control unit, then the other first control unit can be accessed. Advantageously, data for new electrochemical energy storage cells, for example with other cell chemistries, are also located in the memory of the second control unit, so that even when replacing an electrical energy storage cell, correct data for the corresponding electrochemical model are available for data adjustment. If the state of an electrical energy storage cell changes in such a way that, for example, such an electrical energy storage cell ages more strongly than calculated by the electrochemical model, new parameters can then be provided. Furthermore, individual driving behavior and / or the charging strategy used can be better taken into account for power prediction and vehicle range prediction.

[0039] The data of the electrochemical model of the electrochemical energy store include one-dimensional or multi-dimensional characteristic diagrams and / or parameters, in particular temperature, current, state of charge, state of health.

[0040] As a result, the data of the electrochemical model can be kept current, so that a power prediction and a vehicle range prediction can be made more accurately, so that a greater driving pleasure and a greater vehicle range can be achieved with an electrically drivable vehicle.

[0041] The device according to the invention for operating an electrical energy storage cell comprises a plurality of electrochemical energy storage cells, at least one sensor for detecting an electrical variable of the electrochemical energy storage cell, and at least one means, in particular a first control unit for controlling the electrical energy storage cell, which are provided for carrying out the steps of the method according to the invention.

[0042] The method according to the invention is advantageously used in electrical energy storage systems for electric vehicles, hybrid vehicles, plug-in hybrid vehicles, aircraft, pedelecs or electric bicycles, for portable devices for telecommunications or data processing, for electrical hand tools or kitchen appliances, and in stationary storage devices for storing electrical energy, in particular regeneratively captured energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Exemplary embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description.

[0044] in:

[0045] Figure 1 A schematic diagram of an embodiment of the device according to the present invention is shown; and

[0046] Figure 2 shows a schematic diagram of a data set;

[0047] Figure 3a A schematic diagram showing a first electrochemical model;

[0048] Figure 3b A schematic diagram showing a second electrochemical model;

[0049] Figure 4 A flow chart of an embodiment of the method according to the invention is shown. DETAILED DESCRIPTION

[0050] The same reference numerals are used throughout the drawings to denote the same device components.

[0051] Figure 1A schematic diagram of an embodiment of the device according to the invention is shown. An electrically drivable vehicle 100 comprises a first control unit 101 with a memory, an electrical energy storage unit 102 with a plurality of electrochemical energy storage units 103(1), 103(2), 103(n), wherein the first control unit 101 communicates wirelessly with a second control unit 105, for example by means of a radio link. The second control unit 105 with the memory is spatially separated from the vehicle, for example in an IT infrastructure 104 (cloud computing) provided via the Internet. The data of the electrochemical model of the electrical energy storage unit 102 and / or the electrochemical energy storage units 103(1), 103(2), 103(n) are stored in the memory of the first control unit 101. These data are characteristic curves that are dependent on temperature, current, state of charge and other physical variables, i.e., multi-dimensional characteristic curves, and are therefore very memory-intensive.

[0052] Figure 2 An exemplary representation of a data set 200 is shown. The data are grouped (clusters) according to different battery aging stages (SoH) from a new state via different degrees of aging to a state in which the electrical energy storage cell should be replaced due to its too low residual capacity, for example 80%.

[0053] The group is derived from the difference between a model voltage variable calculated by means of an electrochemical model and a detected voltage variable, for example the voltage of an electrical energy storage cell measured by means of a voltage sensor. If there is a certain voltage difference from these two voltage variables, which is greater than the measurement accuracy of the voltage sensor and the A / D converter of the signal processing, then the next group can be adjusted.

[0054] The granularity of the grouping, the conditions under which the comparative measurements must be carried out and the frequency of the comparative measurements determine the quality of the method according to the invention.

[0055] The sensor arrangement plus electronics has an accuracy of approximately ±25 mV, which means that the measurement accuracy of the cell voltage measurement is approximately 50 mV. A voltage deviation can only be reliably inferred if the difference between the calculated model voltage variable and the detected voltage variable is greater than this 50 mV.

[0056] For an electrical energy storage cell 102 with a lithium-ion energy storage device, which is operated in a voltage range of 4.2 V to about 3 V, approximately 20 groups are theoretically produced. On the other hand, a significant reduction in the state of charge of approximately 10% occurs only at a voltage difference of 70 mV, which results in approximately 10 groups. The electrical energy storage cell 102 is operated from a brand new state with a charge capacity of 100% to an aged state with a charge capacity of 80%. When this range is divided evenly, a step size of 5% and thus four groups 201, 202, 203, 204 are produced, which are sufficient for currently available lithium-ion energy storage devices.

[0057] Finer granularity can advantageously be achieved with additional effort in the aging measurement of electrochemical energy stores 103 ( 1 ), 103 ( 2 ), 103 ( n ) and in the determination of the parameters of the electrochemical energy stores.

[0058] Figure 3a Schematic diagram of a first electrochemical model 300a is shown. The electrochemical model 300a of the electrical energy storage cell 102 is usually drawn in the battery management system of the first control unit 101 as an equivalent circuit model in the form of an open-circuit voltage source and an R-RC element. Another embodiment is a second electrochemical model 300b with a plurality of RC elements connected in series with the previous RC element, such as Figure 3b Thus, the parameters of the model for these electrochemicals are the no-load voltage (UOCV), the two resistor values ​​(Ri and R1), and the capacitor capacitance (C1).

[0059] Figure 4 A flow chart of an embodiment of a method according to the invention for aligning data of a first control unit 101 for controlling an electrical energy storage cell 102 with a plurality of electrochemical energy storage devices 103(1), 103(2), 103(n) with a second control unit 105 for determining precise prediction values ​​is shown. The method starts in step 400. In step 401, a large amount of data of an electrochemical model of the electrical energy storage cell 102 is provided in groups for different aging stages of the electrical energy storage cell 102 using a memory of the second control unit 105.

[0060] Step 402 includes comparing the determined usage variable, which represents the cyclic aging and / or calendar aging of the electrical energy storage cell 102 and / or the electrochemical energy storage 103 (1), 103 (2), 103 (n), with a predetermined threshold value. In addition, step 402 includes checking whether the electrical energy storage cell 102 is operating without errors. If the determined usage variable exceeds the predetermined threshold value and / or the electrical energy storage cell 102 is operating without errors, a first voltage variable representing the voltage of the electrochemical energy storage 103 (1), 103 (2), 103 (n) is detected.

[0061] In addition, step 402 includes discarding abnormal values ​​of the acquired voltage variable and comparing the dispersion of the acquired voltage variable with a predetermined threshold value. If the dispersion does not exceed the predetermined threshold value, then in step 403 an average value of the acquired first voltage variable is formed.

[0062] In step 404, it is checked whether the voltage difference between the formed mean value of the acquired first voltage variable and the model voltage variable calculated with the aid of the data set provided by the memory of the first control unit 101 exceeds a predetermined threshold value. If the threshold value is exceeded, at least one data set of the memory of the first control unit 101 is wirelessly aligned with a data set of the memory of the second control unit 105 in step 405, otherwise the method is continued in step 402. The threshold value is predetermined depending on the granularity of the data set.

[0063] By aligning the data, a more precise prediction of the remaining range and the power that can be drawn is made possible. In addition, simple adaptations to specific design variants and to new electrical energy storage units are made possible.

[0064] A comparison measurement is performed in step 406 . For this purpose, in step 406 a second voltage variable representing the voltage of electrochemical energy store 103 ( 1 ), 103 ( 2 ), 103 (n) is detected and an average value of the detected second voltage variable is formed.

[0065] Step 407 includes generating a signal as a function of the voltage difference between the formed mean value of the detected second voltage variable and the model voltage variable calculated with the aid of the aligned data set. If the voltage difference exceeds a predetermined threshold value, a fault signal is generated in step 408 .

[0066] The method ends in step 409 or continues in step 402 and is repeated cyclically.

[0067] The method according to the invention is advantageously suitable for virtually any electrochemical energy store and in principle any vehicle component which has a connection to an external storage medium, for example a connection to cloud computing.

Claims

1. A method for aligning data of a first control unit for controlling an electrical energy storage unit having a plurality of electrochemical energy storage devices with a second control unit for determining an exact prediction value, comprising the following steps: a) providing a plurality of data sets of an electrochemical model of the electrical energy storage cell for different aging stages of the electrical energy storage cell by means of a memory of the second control unit; b) providing at least one of the data sets by means of a memory of the first control unit; c) detecting a first voltage variable representing the voltage of the plurality of electrochemical energy stores; d) forming an average value of the acquired first voltage parameter; e) wirelessly aligning at least one data set of the memory of the first control unit with a data set of the memory of the second control unit if a voltage difference between the formed average value of the detected first voltage variable and a model voltage variable calculated with the aid of the data set provided by the memory of the first control unit exceeds a predetermined threshold value.

2. The method according to claim 1, further comprising the steps of: f) detecting a second voltage variable representing the voltage of the electrochemical energy store; g) forming an average value of the acquired second voltage parameter; h) generating a signal as a function of a voltage difference between the formed mean value of the detected second voltage variable and a model voltage variable calculated with the aid of the aligned data set.

3. The method according to claim 2, wherein: If the voltage difference exceeds the predetermined threshold value, the generated signal is a fault signal.

4. The method according to any one of claims 1 to 3, further comprising the steps of: c.1) comparing the determined usage variable representing the cyclic aging and / or calendar aging of the electrical energy storage cell and / or the electrochemical energy storage device with the predetermined threshold value; and / or c.2) checking whether the electrical energy storage unit operates without fault; c.3) If the determined usage variable exceeds the predetermined threshold value and / or the electrical energy storage cell operates without errors, step c) is carried out.

5. The method according to any one of claims 1 to 3, further comprising the steps of: d.1) Discard abnormal values ​​of the collected voltage parameters.

6. The method according to any one of claims 1 to 3, further comprising the steps of: d.2) comparing the dispersion degree of the collected voltage parameter with the predetermined threshold value; d.3) If the dispersion degree does not exceed the predetermined threshold, execute step d).

7. The method according to any one of claims 1 to 3, further comprising the steps of: e.1) checking the current operating state of the electrical energy storage unit; e.2) If the electrical energy storage unit is out of service, step e) is performed.

8. The method according to any one of claims 1 to 3, wherein: The data of the electrochemical model of the electrochemical energy store include one-dimensional or multi-dimensional characteristic diagrams and / or parameters.

9. The method according to claim 8, wherein: The parameters are temperature, current, state of charge, state of health.

10. Device for operating an electrical energy storage unit, comprising: Multiple electrochemical energy storage devices, at least one sensor for detecting a voltage variable of the plurality of electrochemical energy stores, and A first control unit and a second control unit for controlling the electrical energy storage cell are provided for carrying out the steps of the method as claimed in claim 1 .

11. Use of the method according to any one of claims 1 to 9 in electrical energy storage systems for electric vehicles, hybrid vehicles, aircraft, for portable devices for telecommunications or data processing, for electrical hand tools or kitchen appliances, and in stationary stores for storing regeneratively captured electrical energy.

12. The use according to claim 11, wherein: The hybrid vehicle is a plug-in hybrid vehicle. 13 . Use of the method according to claim 1 in an electrical energy storage system for an electric assisted vehicle or an electric bicycle.

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