Vehicle cloud system, battery pack data sampling method, and abnormal vehicle end determination method

Abstract

The application discloses a vehicle cloud system, a battery pack data sampling method and an abnormal vehicle end determination method. The vehicle cloud system comprises a vehicle end and a cloud end. The vehicle end is configured to: sample voltage data and current data of a battery pack in real time to obtain data sampling points; determine data sampling points satisfying a preset condition as effective sampling points; and transmit the effective sampling points and corresponding time stamps to the cloud end. The cloud end is configured to: calculate a battery pack SOC value corresponding to the effective sampling points; select effective sampling points within a preset time window according to the time stamps, the battery pack SOC value and a preset extreme value, to obtain an effective sampling point set, the battery pack SOC value extreme value of the effective sampling point set being greater than the preset extreme value; calculate a cell consistency parameter of the battery pack according to the effective sampling point set; and determine a vehicle end with a cell consistency anomaly as an abnormal vehicle end. The application can improve the accuracy of cell consistency determination, and reduce network traffic cost and data storage cost.

Description

Technical Field

[0001] This application relates to the field of new energy vehicle technology, specifically to a vehicle-cloud system, a battery pack data sampling method, and a method for determining abnormal vehicle conditions. Background Technology

[0002] In existing vehicle-to-cloud systems, current data during the charging phase is typically transmitted from the vehicle to the cloud in real time. The cloud receives the current data, stores it in a database, and uses the current data and corresponding time to calculate the change in battery cell capacity at the vehicle. The consistency of each battery cell is then judged based on the change in battery cell capacity.

[0003] However, because existing technologies only select current data during the charging phase, the reliability of the obtained cell capacity changes is low, thus affecting the accuracy of the consistency judgment of vehicle-side cells. Furthermore, real-time transmission of current data requires significant network traffic costs and cloud data storage costs. Summary of the Invention

[0004] In view of this, this application provides a vehicle-to-cloud system, a battery pack data sampling method, and a method for determining abnormal vehicle terminals, to improve the accuracy of cell consistency judgment and reduce the network traffic cost of the vehicle-to-cloud system and the data storage cost in the cloud. The technical solution of this application is as follows:

[0005] This application provides a vehicle-to-cloud system, including a vehicle terminal and a cloud terminal. The vehicle terminal includes multiple battery packs, and the cloud terminal is communicatively connected to multiple vehicle terminals. The vehicle terminal is used to: sample voltage and current data of the battery packs in real time to obtain data sampling points; determine data sampling points that meet preset conditions as valid sampling points, and associate and transmit the valid sampling points and their corresponding timestamps to the cloud terminal; the cloud terminal is used to: calculate the SOC value of the battery pack corresponding to the valid sampling points; select valid sampling points within a preset time window range according to the timestamp, the SOC value of the battery pack, and a preset extreme value to obtain a set of valid sampling points, wherein the extreme value of the SOC value of the battery pack in the set of valid sampling points is greater than the preset extreme value; calculate the cell consistency parameters of the battery pack according to the set of valid sampling points; and determine vehicle terminals with abnormal cell consistency as abnormal vehicle terminals according to the cell consistency parameters.

[0006] In one embodiment of this application, determining a data sampling point that meets preset conditions as a valid sampling point and transmitting the valid sampling point and its corresponding timestamp to the cloud includes: calculating the battery pack net capacity, pure ohmic voltage drop, and polarization voltage drop component of the data sampling point based on the voltage data and the current data; determining that the change in battery pack net capacity is greater than a preset change, the pure ohmic voltage drop is less than a first threshold, and the polarization voltage drop component is less than a second threshold, and then determining the corresponding data sampling point as the valid sampling point; wherein, the change in battery pack net capacity is the change in battery pack net capacity relative to the previous valid sampling point.

[0007] In one embodiment of this application, the effective sampling points include cell voltage, cumulative equalization capacity of the cell, net capacity of the battery pack, pure ohmic voltage drop, and polarization voltage drop component. The step of calculating the cell consistency parameters of the battery pack based on the effective sampling point set includes: calculating the maximum SOC difference value of each cell in the effective sampling point set based on the cell voltage; filtering and removing effective sampling point sets whose maximum SOC difference value is less than a third threshold to obtain a retained sampling point set; calculating the cell capacity of each cell in the retained sampling point set based on the cumulative equalization capacity of the cell, the net capacity of the battery pack, the pure ohmic voltage drop, and the polarization voltage drop component; and obtaining the cell consistency parameters based on the cell capacity.

[0008] In one embodiment of this application, the step of calculating the cell consistency parameters of the battery pack based on the set of valid sampling points further includes: filtering and removing valid sampling points in the set of valid sampling points that are within a preset SOC value range.

[0009] In one embodiment of this application, calculating the cell capacity of each cell in the reserved sampling point set includes: calculating the SOC value of the cell corresponding to the reserved sampling point set based on the pure ohmic voltage drop and the polarization voltage drop component; calculating the cell charge change value corresponding to the reserved sampling point set based on the cell SOC value, the cell cumulative equalization charge, and the battery pack net charge; and calculating the cell capacity of each cell in the reserved sampling point set based on the cell charge change value and the cell SOC value.

[0010] In one embodiment of this application, calculating the SOC value of the cell corresponding to the retained sampling point set includes: calculating the cell open-circuit voltage of each cell in the retained sampling point set based on the pure ohmic voltage drop and the polarization voltage drop component; and obtaining the cell SOC value based on the cell open-circuit voltage and the OCV-SOC characteristic curve.

[0011] In one embodiment of this application, obtaining the cell consistency parameter based on the cell capacity includes: calculating the standard deviation of cell capacity, the range of cell capacity, and the center difference of cell capacity based on the cell capacities of all the cell capacities of the retained sampling points, as the cell consistency parameter.

[0012] In one embodiment of this application, determining the vehicle end with abnormal cell consistency based on the cell consistency parameters as an abnormal vehicle end includes: determining the vehicle end corresponding to the cell capacity standard deviation being greater than a fourth threshold as an abnormal vehicle end with poor cell capacity consistency; determining the vehicle end corresponding to the cell capacity range being greater than a fifth threshold as an abnormal vehicle end with excessively large cell capacity range; and determining the vehicle end corresponding to the cell center difference being greater than a sixth threshold as an abnormal vehicle end with some cell capacities out of the sort.

[0013] A second aspect of this application provides a battery pack data sampling method applied to a vehicle. The vehicle includes multiple battery packs and is connected to a cloud. The battery pack data sampling method includes: sampling the voltage and current data of the battery packs in real time to obtain data sampling points; determining data sampling points that meet preset conditions as valid sampling points; and associating and transmitting the valid sampling points and their corresponding timestamps to the cloud.

[0014] A third aspect of this application provides a method for determining abnormal vehicle terminals, applied in a cloud environment, wherein the cloud environment is communicatively connected to multiple vehicle terminals. The method includes: receiving valid sampling points and corresponding timestamps transmitted by the vehicle terminals; calculating the battery pack SOC value corresponding to the valid sampling points; selecting valid sampling points within a preset time window range based on the timestamps, the battery pack SOC value, and a preset extreme value to obtain a set of valid sampling points, wherein the extreme value of the battery pack SOC value in the set of valid sampling points is greater than the preset extreme value; calculating the cell consistency parameters of the battery pack based on the set of valid sampling points; and determining that the vehicle terminal with abnormal cell consistency is an abnormal vehicle terminal based on the cell consistency parameters.

[0015] In this application, the vehicle-side system, upon acquiring data sampling points at the current moment, determines whether the data sampling points meet preset conditions. Data sampling points that meet the preset conditions are transmitted to the cloud as valid sampling points along with their timestamps, while data sampling points that do not meet the preset conditions are removed. This improves the accuracy of vehicle-side management calculations performed by the cloud based on sampling points, saves network traffic for vehicle-side data transmission, and reduces cloud data storage costs. Meanwhile, in the cloud, a set of valid sampling points with extremely high battery pack SOC values ​​is further constructed through a preset time window to calculate the cell capacity, thereby improving the reliability of the calculated cell capacity. Attached Figure Description

[0016] Figure 1This is a schematic block diagram of a vehicle-to-cloud system provided in an embodiment of this application.

[0017] Figure 2 This is a schematic flowchart of a battery pack data sampling method provided in an embodiment of this application.

[0018] Figure 3 This is a flowchart illustrating a method for determining abnormal vehicle terminals provided in an embodiment of this application.

[0019] Figure 4 This is a flowchart illustrating a method for determining valid sampling points provided in an embodiment of this application.

[0020] Figure 5 This is a flowchart illustrating a method for calculating cell consistency parameters provided in an embodiment of this application.

[0021] Figure 6 This is a flowchart illustrating a cell capacity calculation method provided in an embodiment of this application.

[0022] Figure 7 This is a flowchart illustrating a method for calculating the SOC value of a battery cell according to an embodiment of this application.

[0023] Figure 8 This is a schematic diagram of the process for determining abnormal cell consistency parameters on the vehicle side, provided in an embodiment of this application. Detailed Implementation

[0024] It should be noted that in the embodiments of this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and drawings of this application are used to distinguish similar objects, not to describe a specific order or sequence.

[0025] It should also be noted that the methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchanged, and some steps can also be deleted.

[0026] In existing vehicle-to-cloud systems, current data during the charging phase is typically transmitted from the vehicle to the cloud in real time. The cloud receives the current data, stores it in a database, and uses the current data and corresponding time to calculate the change in battery cell capacity at the vehicle. The consistency of each battery cell is then judged based on the change in battery cell capacity.

[0027] However, because existing technologies only select current data during the charging phase, the reliability of the obtained cell capacity changes is low, thus affecting the accuracy of the consistency judgment of vehicle-side cells. Furthermore, real-time transmission of current data requires significant network traffic costs and cloud data storage costs.

[0028] This application provides a vehicle-to-cloud system, a battery pack data sampling method, and a method for identifying abnormal vehicle terminals, which can improve the accuracy of cell consistency judgment and reduce the network traffic cost of the vehicle-to-cloud system and the data storage cost in the cloud.

[0029] Please refer to Figure 1 , Figure 1 This is a schematic block diagram of a vehicle-to-cloud system provided in an embodiment of this application. The vehicle-to-cloud system 100 includes a vehicle-side unit 110 and a cloud-side unit 120. The vehicle-side unit 110 includes multiple battery packs 111, and the cloud-side unit 120 is communicatively connected to the multiple vehicle-side units 110. In this embodiment, the vehicle-side unit 110 includes vehicles equipped with power batteries, such as pure electric vehicles and hybrid electric vehicles.

[0030] In some embodiments, cloud 120 may communicate with multiple vehicle terminals 110, and vehicle cloud system 100 may include multiple cloud terminals 120.

[0031] Next, combine Figure 1 This application introduces a battery pack data sampling method provided in an embodiment, wherein the method is applied to and executed by the vehicle. Please refer to... Figure 2 Specifically, it includes the following steps:

[0032] Step S21: Sample the voltage and current data of the battery pack in real time to obtain data sampling points.

[0033] In this embodiment of the application, the vehicle end includes a main controller, which is used to connect to the battery management unit of each battery pack in the vehicle end. When the battery pack in the vehicle end is working, the main controller can sample the voltage and current of the battery pack in real time through the battery management unit to obtain the voltage data and current data as the data sampling points of the battery pack.

[0034] Step S22: Determine the data sampling points that meet the preset conditions as valid sampling points, and associate and transmit the valid sampling points and their corresponding timestamps to the cloud.

[0035] In this embodiment, when the main controller obtains the data sampling point at the current moment, it will determine whether the data sampling point meets the preset conditions. The data sampling points that meet the preset conditions will be transmitted to the cloud as valid sampling points with associated timestamps, and the data sampling points that do not meet the preset conditions will be removed. This will improve the accuracy of the cloud's vehicle-side management calculations based on the sampling points, save network traffic for vehicle-side data transmission, and save the cost of cloud data storage.

[0036] Next, combine Figure 1 This application introduces a method for determining abnormal vehicle terminals, which is applied in the cloud and executed by the cloud. Please refer to... Figure 3 Specifically, it includes the following steps:

[0037] Step S31: Receive the valid sampling points and corresponding timestamps transmitted from the vehicle end.

[0038] In this embodiment, the cloud includes various computer devices, such as servers. The cloud communicates with multiple vehicle terminals and receives valid sampling points and timestamps transmitted by the vehicle terminals in real time. Specifically, when the cloud communicates with multiple vehicle terminals, upon receiving a valid sampling point and timestamp transmitted by a particular vehicle terminal, it can associate and store the information corresponding to that vehicle terminal with the valid sampling point and timestamp.

[0039] Step S32: Calculate the SOC value of the battery pack corresponding to the valid sampling point.

[0040] In this embodiment of the application, after receiving a valid sampling point, the cloud can also calculate the SOC value of the battery pack corresponding to the valid sampling point based on the voltage data and current data in the valid sampling point.

[0041] Step S33: Based on the timestamp, battery pack SOC value, and preset extreme value, select valid sampling points within a preset time window range to obtain a set of valid sampling points. The extreme value of the battery pack SOC value in the set of valid sampling points is greater than the preset extreme value.

[0042] In this embodiment of the application, after the cloud obtains the battery pack SOC value of all valid sampling points corresponding to the vehicle, it can select more suitable valid sampling points for cell consistency judgment based on the battery pack SOC value, and remove valid sampling points that are not suitable for cell consistency judgment to form a set of valid sampling points.

[0043] The cloud-based system can first select all battery pack SOC values ​​within a preset time window range and calculate the extreme values ​​of the battery pack SOC values. This involves calculating the difference between the maximum and minimum SOC values ​​within the preset time window range and determining if the current extreme value of the battery pack SOC value is greater than the preset extreme value. If the current extreme value of the battery pack SOC value is not greater than the preset extreme value, the preset time window is moved to select new battery pack SOC values ​​for further calculation and magnitude determination, until the aforementioned effective sampling point set is obtained.

[0044] In some embodiments, when moving the preset time window, the window length can be moved forward by a preset multiple or backward by a preset multiple, such as moving forward by half the window length, which is not limited here.

[0045] If, within the preset time window, the extreme value of the battery pack's SOC still does not meet the preset limit, the subsequent steps can be stopped. It's understood that if the extreme value of the battery pack's SOC is too small, the reliability of the cell capacity calculated in subsequent steps will be low.

[0046] This application improves the reliability of the calculated cell capacity by obtaining a set of valid sampling points where the extreme value of the battery pack's SOC value is greater than a preset extreme value.

[0047] Step S34: Calculate the cell consistency parameters of the battery pack based on the effective sampling point set.

[0048] In this embodiment of the application, after obtaining the set of valid sampling points corresponding to the vehicle, the cloud can calculate the cell capacity of each cell in the battery pack based on the set of valid sampling points, and then obtain the cell consistency parameters of the battery pack based on the capacity of each cell.

[0049] Step S35: Determine the vehicle end with abnormal cell consistency based on the cell consistency parameters.

[0050] In this embodiment of the application, after the cloud determines the abnormal vehicle terminal based on the cell consistency parameters, it can also notify the abnormal vehicle terminal or the after-sales personnel of the vehicle terminal to avoid serious failures of the vehicle terminal due to inconsistent cell capacity.

[0051] In some embodiments, please refer to Figure 4 The above step S22 may further include the following steps:

[0052] Step S41: Calculate the battery pack net capacity, pure ohmic voltage drop, and polarization voltage drop components at the data sampling points based on the voltage and current data.

[0053] In this embodiment of the application, the voltage data includes the battery pack voltage value. Cell voltage Cell voltage equalization capacity ,in, This indicates the cell serial number. Current data includes the battery pack current value. Among them, the net capacity of the battery pack is used This indicates that the pure ohmic voltage drop is used Indicated. Taking a battery pack composed of two cells as an example, the polarization voltage drop component of the first cell is represented by... This indicates that the polarization voltage drop component of the second cell is used... Indicates that the polarization voltage drop is used express:

[0054] ;

[0055] Among them, the net capacity of the battery pack is used The formula is as follows:

[0056] ;

[0057] In the formula, This represents the net charge of the battery pack at the current sampling time. This represents the net charge of the battery pack at the previous sampling time. This is the battery pack current value sampled in this test. This represents the time interval between the current sampling time and the previous sampling time.

[0058] Pure Ohmic Voltage Drop The formula is as follows:

[0059] ;

[0060] In the formula, This represents the pure ohmic voltage drop at the current sampling moment. This indicates the pure ohmic internal resistance of the battery pack. This is the battery pack current value sampled in this test.

[0061] The above polarization voltage drop component is used and polarization voltage drop component The formula is as follows:

[0062] ;

[0063] ;

[0064] In the formula, This represents the polarization voltage drop component of the first cell at the current sampling moment. This represents the polarization voltage drop component of the first cell at the previous sampling time. It is an exponential function with the natural constant e as its base. and These are the resistance and capacitance values ​​in the equivalent circuit model of the first battery cell. This is the battery pack current value sampled in this test. This represents the polarization voltage drop component of the second cell at the current sampling moment. This represents the polarization voltage drop component of the second cell at the previous sampling time. and These are the resistance and capacitance values ​​of the equivalent circuit model of the second battery cell.

[0065] Step S42: When the change in net battery charge is greater than the preset change, the pure ohmic voltage drop is less than the first threshold, and the polarization voltage drop component is less than the second threshold, the corresponding data sampling point is determined as a valid sampling point.

[0066] In this embodiment, the change in battery pack net capacity is the change in battery pack net capacity relative to the previous valid sampling point. The valid sampling points transmitted to the cloud include the timestamp of the current sampling time, battery pack voltage, battery pack current, battery pack net capacity, pure ohmic voltage drop, voltage drop components for each polarization, voltage of each cell, and accumulated equalization capacity of each cell. The accumulated equalization capacity of the cells is the accumulated capacity released during cell equalization. When the battery management unit detects poor voltage consistency among the cells in the battery pack, it can control the cells with higher voltages to undergo discharge equalization.

[0067] In some embodiments, valid sampling points include cell voltage, cell cumulative equalization capacity, battery pack net capacity, pure ohmic voltage drop, and polarization voltage drop component. Please refer to [reference needed]. Figure 5 The above step S34 may further include the following steps:

[0068] Step S51: Filter and remove valid sampling points that are within the preset SOC value range.

[0069] In this embodiment of the application, the SOC value of the battery pack corresponding to each valid sampling point in the valid sampling point set can be defined. Define the set of valid sampling points The maximum value is , The minimum value is ,according to Define a high SOC threshold, for example and according to Define a low SOC threshold, for example The aforementioned preset SOC value range can be from a low SOC threshold to a high SOC threshold, thereby reducing the amount of computation in the cloud.

[0070] Furthermore, the cloud can also define higher... The valid sampling points corresponding to the battery pack SOC value are high SOC data points, and those defined as below SOC are... The effective sampling points corresponding to the SOC value of the battery pack are low SOC data points. The high SOC data points in the effective sampling point set are combined with the adjacent low SOC data points to form a data group for subsequent calculations.

[0071] Step S52: Calculate the maximum difference in SOC of each effective sampling point set based on the cell voltage.

[0072] In this embodiment of the application, in order to further reduce the amount of computation in the cloud and save cloud computing resources, the cloud can also calculate the maximum difference value of cell SOC for each set of valid sampling points based on the cell voltage in the valid sampling points. It can be understood that battery packs with smaller maximum difference values ​​of cell SOC have no risk of inconsistent cell capacity.

[0073] The calculation method for the maximum difference in cell SOC includes: defining the highest cell voltage of the effective sampling point set as... The lowest voltage of the battery cell is The number of cells in the battery pack is defined as follows. The highest OCV voltage of the battery cell Minimum OCV voltage of battery cell . To retain the first sampling point in the set The pure ohmic voltage drop at each valid sampling point To retain the first sampling point in the set The first polarization voltage drop component of each valid sampling point To retain the first sampling point in the set The second polarization voltage drop component of each valid sampling point.

[0074] The pre-defined OCV-SOC mapping curve of the battery cell is represented by a function. This indicates that the SOC value of the battery cell is defined as follows: , The maximum difference in SOC among cells within the effective sampling point set is then... It can be calculated using the following formula:

[0075] .

[0076] Step S53: Filter and remove the set of valid sampling points whose maximum difference in cell SOC is less than the third threshold, and obtain the set of retained sampling points.

[0077] In this embodiment, after calculating the maximum difference value of cell SOC corresponding to each valid sampling point set, the cloud can remove the valid sampling point set whose maximum difference value of cell SOC is less than the third threshold. That is, the valid sampling point set without cell capacity inconsistency risk of the battery pack is removed, and the valid sampling point set with cell capacity inconsistency risk is retained as the above-mentioned retained sampling point set, thereby reducing the amount of computation when the cloud performs subsequent steps.

[0078] Step S54: Calculate the cell capacity of each cell in the retained sampling point set based on the cell's accumulated equalization charge, the battery pack's net charge, the pure ohmic voltage drop, and the polarization voltage drop component.

[0079] Step S55: Obtain cell consistency parameters based on cell capacity.

[0080] In this embodiment, the cloud can extract the cumulative balanced charge of the cells, the net charge of the battery pack, the pure ohmic voltage drop, and the polarization voltage drop components from the retained sampling point set, and use them to calculate the cell capacity of each cell in the retained sampling point set.

[0081] In some embodiments, please refer to Figure 6 The above step S54 may further include the following steps:

[0082] Step S61: Calculate the SOC value of the cell corresponding to the retained sampling point set based on the pure ohmic voltage drop and polarization voltage drop components.

[0083] Step S62: Calculate the change in cell charge corresponding to the retained sampling point set based on the cell SOC value, the cell cumulative equalization charge, and the battery pack net charge.

[0084] In this embodiment of the application, the net charge of the entire package for the high SOC data point of the k-th data group in step S51 above is defined as... Define the cumulative equalization charge of the i-th cell in the high SOC data point of the k-th data group as . Define the net charge of the entire package for the low SOC data point in the k-th data group as . Define the cumulative equalization capacity of the cells at the low SOC data point in the k-th data group as . Then, the change in charge of the i-th cell in the k data sets is... It can be calculated using the following formula:

[0085] ;

[0086] It is understandable that this solution takes into account the changes in charge generated by cell balancing in the changes in cell capacity, which can further improve the reliability of cell capacity consistency judgment.

[0087] Step S63: Calculate the cell capacity of each cell in the retained sampling point set based on the cell charge change value and cell SOC value.

[0088] In this embodiment of the application, the SOC value of the i-th cell of the high SOC data point in the k-th data group is defined as... Define the SOC value of the i-th cell in the low SOC data point of the k-th data group as... Define the SOC change value of the i-th cell in the k-th data group as... The central value of the normal distribution is used Representation, variance express, Calculated by the following formula:

[0089] ;

[0090] definition The probability distribution is in the form of ,in, - , . for The central value of the normal distribution, for The central value of the normal distribution, for The variance of the normal distribution, for The variance of the normal distribution.

[0091] Define the capacity of the i-th cell in the k-th data group as ,but It can be calculated using the following formula:

[0092] ;

[0093] Define the first sampling point in the set of retained sampling points. The SOC value of the i-th cell at each valid sampling point is , The probability distribution is shown in the following form:

[0094] ,in, , . for The central value of the normal distribution, for The variance of the normal distribution.

[0095] Furthermore, assuming the total number of the above data sets is Q, and the final capacity of the i-th cell is... , It is obtained by weighting the cell capacities calculated from each data set. The calculation formula is as follows:

[0096] ;

[0097] It is understandable that the smaller the variance of the calculated cell capacity from the data set, the higher the reliability of the obtained cell capacity value, and the better it is for calculating the final capacity. The higher the weight of the formula, the more accurate the final capacity of the battery cell will be.

[0098] In some embodiments, please refer to Figure 7 The above step S61 may further include the following steps:

[0099] Step S71: Calculate the cell open-circuit voltage of each cell in the retained sampling point set based on the pure ohmic voltage drop and polarization voltage drop components.

[0100] In this embodiment of the application, the first sample point in the reserved sampling point set is defined. The voltage of the i-th cell at each valid sampling point is The pure ohmic voltage drop and polarization voltage drop components are respectively , , The open-circuit voltage of the i-th cell is Since each of the above voltages actually has a certain degree of error, a probability distribution can more accurately describe each voltage. Assume that... , , , , All conform to a normal distribution. The central value of a normal distribution is... Representation, variance If we express this, then we have:

[0101] ; ; ; ; ;

[0102] In the formula, It is the voltage of the i-th battery cell transmitted from the vehicle to the cloud. It is the pure ohmic voltage drop transmitted from the vehicle to the cloud. It is the polarization voltage drop component 1 transmitted from the vehicle to the cloud. This is the polarization voltage drop component 2 transmitted from the vehicle to the cloud. The value is determined by the accuracy of the battery voltage detection sensor. It can be calculated using the following formula:

[0103] ;

[0104] In the formula, yes hour The basic variance Variance varies The coefficient increases as the absolute value of the coefficient increases. Similarly, , They can be calculated using the following formulas respectively.

[0105] ; ;

[0106] In the formula, yes hour The basic variance yes hour The fundamental variance. It is approximated that the pure ohmic voltage drop and polarization voltage of each cell can be approximated as equal to the total package voltage. Therefore, the pure ohmic voltage drop and polarization voltage drop components of each cell are respectively... , , ,but:

[0107] ; ; ;

[0108] The number of cells in the battery pack is represented by letters. It means that the first The open-circuit voltage of each cell at each valid sampling point is used It means that among them Indicates the cell serial number. It can also be represented by a normal distribution, then:

[0109] ;

[0110] Open circuit voltage of the i-th cell It can be calculated using the following formula:

[0111] ; central value Calculated by the following formula:

[0112] ;

[0113] in, yes variance The calculation formula is shown below:

[0114] .

[0115] Step S72: Obtain the cell SOC value based on the cell open-circuit voltage and the OCV-SOC characteristic curve.

[0116] In this embodiment, after obtaining the battery open-circuit voltage at valid sampling points, the SOC value of each cell can be obtained by transforming the battery OCV-SOC characteristic curve. The mapping relationship between OCV and SOC is expressed by a function. Representation. Define the first in the set of retained sampling points. The SOC value of the i-th cell at each valid sampling point is , It is approximately believed that It still conforms to a normal distribution, as can be obtained from the above formula. The probability distribution is shown in the following form:

[0117] ;

[0118] in, , , yes The derivative of .

[0119] It is understandable that after calculating the cell capacity of each cell in the battery pack, cell consistency parameters are obtained based on the cell capacity. Specifically, this may include: calculating the standard deviation of cell capacity, the range of cell capacity, and the center difference of cell capacity based on the cell capacity of all cells at the retained sampling points, as cell consistency parameters.

[0120] Please refer to Figure 8 The above step S35 may specifically include the following steps:

[0121] Step S81: Determine the vehicle end corresponding to the cell capacity standard deviation being greater than the fourth threshold as an abnormal vehicle end with poor cell capacity consistency.

[0122] Step S82: Determine the vehicle end corresponding to the cell capacity range being greater than the fifth threshold as an abnormal vehicle end with excessively large cell capacity range.

[0123] Step S83: Determine the vehicle terminal corresponding to the cell center difference being greater than the sixth threshold as an abnormal vehicle terminal with some cells having outlier capacity.

[0124] In this embodiment of the application, the standard deviation of the cell capacity of the retained sampling points is defined as follows: The average capacity of all cells at the sampling points is retained. The range of cell capacity at the sampling points is retained. The difference between the average and minimum cell capacity is the cell capacity center difference, which is expressed as... express, and The ratio is the maximum outlier of the monomer capacity, used as... If it means:

[0125] ; ; ; ; .

[0126] This application embodiment also provides a computer storage medium storing a computer program. When the computer program is executed by a processor, the processor executes the above-described battery pack data sampling method or abnormal vehicle end determination method.

[0127] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer storage medium or transmitted through the computer storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., Digital Versatile Discs (DVDs)), or semiconductor media (e.g., solid-state disks (SSDs)).

[0128] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks. Unless otherwise specified, the technical features of this embodiment and its implementation can be combined arbitrarily.

[0129] The embodiments described above are merely preferred embodiments of this application and are not intended to limit the scope of this application. Any modifications and improvements made by those skilled in the art to the technical solutions of this application without departing from the spirit of this application should fall within the protection scope defined by the claims of this application.

Claims

1. A car cloud system, characterized by, The vehicle end includes a plurality of battery packs, and the cloud end is in communication connection with the plurality of vehicle ends; The vehicle end is configured to: sample voltage data and current data of the battery packs in real time to obtain data sampling points; determine data sampling points satisfying a preset condition as valid sampling points, and transmit the valid sampling points and corresponding time stamps to the cloud end in association; The cloud end is configured to: calculate battery pack SOC values corresponding to the valid sampling points; select valid sampling points in a preset time window according to the time stamps, the battery pack SOC values, and a preset extreme value, to obtain a valid sampling point set, an extreme value of the battery pack SOC values of the valid sampling point set being greater than the preset extreme value; calculate a cell consistency parameter of the battery pack according to the valid sampling point set; determine a vehicle end with a cell consistency anomaly as an abnormal vehicle end according to the cell consistency parameter. The valid sampling points include cell voltages, and the calculation of the cell consistency parameter of the battery pack according to the valid sampling point set includes: calculating a maximum difference value of cell SOC of each valid sampling point set according to the cell voltages; screening and removing the valid sampling point set with a cell SOC maximum difference value less than a third threshold value to obtain a reserved sampling point set; obtaining the cell consistency parameter according to cell capacities of each cell in the reserved sampling point set.

2. The vehicle cloud system of claim 1, wherein, The determination of the data sampling points satisfying the preset condition as the valid sampling points and the transmission of the valid sampling points and the corresponding time stamps to the cloud end in association include: calculating a battery pack net charge, a pure ohmic voltage drop, and a polarization voltage drop component of the data sampling points according to the voltage data and the current data; determining the corresponding data sampling points as the valid sampling points when a battery pack net charge change is greater than a preset change, the pure ohmic voltage drop is less than a first threshold value, and the polarization voltage drop component is less than a second threshold value; wherein the battery pack net charge change is a change of the battery pack net charge relative to a battery pack net charge of a previous valid sampling point.

3. The car cloud system of claim 1, wherein, The valid sampling points further include cell cumulative equalization charge, battery pack net charge, pure ohmic voltage drop, and polarization voltage drop component. The calculation of the cell consistency parameter of the battery pack according to the valid sampling point set further includes: calculating the cell capacity of each cell in the reserved sampling point set according to the cell cumulative equalization charge, the battery pack net charge, the pure ohmic voltage drop, and the polarization voltage drop component; obtaining the cell consistency parameter according to the cell capacity.

4. The car cloud system of claim 3, wherein, The calculation of the cell consistency parameter of the battery pack according to the valid sampling point set further includes: screening and removing the valid sampling points in a preset SOC value range in the valid sampling point set.

5. The car cloud system of claim 3, wherein, The calculation of the cell capacity of each cell in the reserved sampling point set includes: calculating a cell SOC value corresponding to the reserved sampling point set according to the pure ohmic voltage drop and the polarization voltage drop component; According to the cell SOC value, the cell cumulative equalization electric quantity and the battery pack net electric quantity, a cell electric quantity change value corresponding to the reserved sampling point set is calculated; According to the cell electric quantity change value and the cell SOC value, the cell capacity of each cell in the reserved sampling point set is calculated.

6. The car cloud system of claim 5, wherein, The calculation of the cell SOC value corresponding to the reserved sampling point set comprises: According to the pure ohmic voltage drop and the polarization voltage drop component, the open circuit voltage of each cell in the reserved sampling point set is calculated; According to the open circuit voltage and the OCV-SOC characteristic curve, the cell SOC value is obtained.

7. The car cloud system of claim 3, wherein, The calculation of the cell SOC value corresponding to the reserved sampling point set comprises: According to the pure ohmic voltage drop and the polarization voltage drop component, the open circuit voltage of each cell in the reserved sampling point set is calculated; 8. The vehicle cloud system of claim 7, wherein, According to the open circuit voltage and the OCV-SOC characteristic curve, the cell SOC value is obtained. The calculation of the cell capacity according to the cell consistency parameter comprises: According to all cell capacities of the reserved sampling points, the cell capacity standard deviation, the cell capacity range and the cell capacity center difference are calculated as the cell consistency parameter. The determination of the vehicle end with cell consistency abnormality as the abnormal vehicle end according to the cell consistency parameter comprises:

9. A method for battery pack data sampling, the method comprising: The vehicle end corresponding to the cell capacity standard deviation greater than the fourth threshold value is determined as the abnormal vehicle end with poor cell capacity consistency; The vehicle end corresponding to the cell capacity range greater than the fifth threshold value is determined as the abnormal vehicle end with excessively large cell capacity range; The vehicle end corresponding to the cell center difference greater than the sixth threshold value is determined as the abnormal vehicle end with partial cell capacity outliers. The vehicle end comprises a plurality of battery packs, and the vehicle end is in communication connection with the cloud end; The battery pack data sampling method comprises: Real-time sampling of voltage data and current data of the battery pack to obtain data sampling points; Determine the data sampling points meeting the preset condition as effective sampling points, and associate the effective sampling points and the corresponding time stamps for transmission to the cloud end; 10. An abnormal vehicle end determination method characterized by comprising: The determination of the data sampling points meeting the preset condition as effective sampling points, and the association and transmission of the effective sampling points and the corresponding time stamps to the cloud end comprise: According to the voltage data and the current data, the battery pack net electric quantity, the pure ohmic voltage drop and the polarization voltage drop component of the data sampling points are calculated; According to the battery pack net electric quantity, the pure ohmic voltage drop and the polarization voltage drop component, the corresponding data sampling points are determined as the effective sampling points. The cloud end is in communication connection with a plurality of vehicle ends; The abnormal vehicle end determination method comprises: Receive the effective sampling points and the corresponding time stamps transmitted by the vehicle end; Calculate the battery pack SOC value corresponding to the effective sampling points; According to the time stamps, the battery pack SOC value and the preset extreme value, select the effective sampling points within a preset time window to obtain an effective sampling point set, and the extreme value of the battery pack SOC value of the effective sampling point set is greater than the preset extreme value; According to the effective sampling point set, the cell consistency parameter of the battery pack is calculated; According to the cell consistency parameter, the vehicle end with cell consistency abnormality is determined as the abnormal vehicle end; The effective sampling points comprise cell voltages, and the calculation of the cell consistency parameter of the battery pack according to the effective sampling point set comprises: calculating a maximum difference value of cell SOC of each of the effective sampling point set according to the cell voltage; screening and removing the effective sampling point set with a maximum difference value of cell SOC less than a third threshold value, to obtain a reserved sampling point set; obtaining the cell consistency parameter according to the cell capacity of each cell in the reserved sampling point set.

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