Battery consistency determination method and related product

Abstract

A battery consistency determination method and a related product. The battery consistency determination method comprises: determining a voltage difference corresponding to each data frame; determining a battery SOC interval on the basis of the correspondence between the voltage difference corresponding to each data frame and a battery SOC value in each data frame, wherein the voltage difference corresponding to the battery SOC interval is greater than a set threshold; and determining the difference between the upper limit value of the battery SOC interval and the lower limit value of the battery SOC interval as an SOC offset of a battery.

Description

Battery consistency determination method and related products

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 28, 2023, with application number 202311842059.0 and application name “Battery consistency determination method and related products”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a method for determining battery consistency and related products. Background Art

[0003] The rise and popularity of electric vehicles has made lithium-ion battery packs a core component of vehicle powertrains. Lithium iron phosphate (LFP) batteries, due to their superior safety performance, have become the preferred choice of many battery manufacturers. However, due to the inherent electrochemical properties of LFP batteries, their state of charge (SOC)-open circuit voltage (OCV) curve exhibits a plateau, making it difficult to accurately estimate the charge state of individual cells. This characteristic also frequently plagues LFP batteries with consistency issues. To more effectively manage and maintain battery systems, timely detection of cell consistency issues is essential.

[0004] Currently, battery cell consistency issues are primarily detected due to cell SOC deviation. This typically involves finding the voltage inflection point on the SOC-OCV curve and calculating the SOC deviation for each cell at that inflection point. Current SOC deviation calculation methods require calculating the SOC of each cell at that inflection point, which is computationally intensive.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide a battery consistency determination method and related products, which can reduce the amount of calculation required to determine SOC deviation.

[0007] A first aspect of an embodiment of the present application provides a method for determining consistency of a battery, wherein the battery includes at least two battery cells, and the method includes:

[0008] Determine a voltage difference corresponding to each frame of data, where the voltage difference is the difference between the highest cell voltage and the lowest cell voltage in each frame of data;

[0009] Determining a battery SOC interval based on a correspondence between the voltage difference corresponding to each frame of data and a battery SOC value in each frame of data, wherein the voltage difference corresponding to the battery SOC interval is greater than a set threshold;

[0010] The difference between the upper limit value of the battery SOC interval and the lower limit value of the battery SOC interval is determined as the SOC deviation of the battery, and the SOC deviation of the battery is used to measure the consistency of the battery.

[0011] Optionally, each frame of data is any pre-processed frame data of the battery in a set time period.

[0012] Optionally, the set time period includes at least one of a discharge period, an AC charging period, and a DC charging period.

[0013] Optionally, the preprocessing includes at least one of: sorting by time, removing null values, removing duplicate data, removing invalid values, removing sampling outliers, and removing data that does not meet the algorithm working conditions.

[0014] Optionally, after determining the voltage difference corresponding to each frame of data, the method further includes:

[0015] Performing filtering processing on the voltage difference value corresponding to each frame of data to obtain a processed voltage difference value corresponding to each frame of data;

[0016] The determining the battery SOC interval based on the correspondence between the voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, wherein the voltage difference corresponding to the battery SOC interval is greater than a set threshold, includes:

[0017] A battery SOC interval is determined based on a correspondence between the processed voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, wherein the processed voltage difference corresponding to the battery SOC interval is greater than a set threshold.

[0018] Optionally, filtering the voltage difference corresponding to each frame of data to obtain a processed voltage difference corresponding to each frame of data includes:

[0019] Determining a set of credible voltage difference values ​​among the voltage difference values ​​corresponding to each frame of data within the set time period;

[0020] Performing polynomial fitting based on the credible voltage difference value set to obtain a fitted voltage difference value corresponding to each frame of data within the set time period;

[0021] The fitted voltage difference value corresponding to each frame of data within the set time period is filtered to obtain a processed voltage difference value corresponding to each frame of data.

[0022] Optionally, determining a set of credible voltage difference values ​​among the voltage difference values ​​corresponding to each frame of data within the set time period includes:

[0023] Based on the correspondence between the voltage difference corresponding to each frame of data and the sampling time point corresponding to each frame of data, a first curve of the voltage difference corresponding to each frame of data changing with time within the set time period is obtained;

[0024] Determine a first curve segment in the first curve in which the voltage difference is greater than a first threshold, determine a lower envelope area in the first curve segment, and determine the smallest N voltage difference values ​​in the lower envelope area as a set of credible voltage difference values ​​among the voltage differences corresponding to each frame of data in the set time period, where N is an integer greater than or equal to 2.

[0025] Optionally, determining the battery SOC range based on the correspondence between the processed voltage difference corresponding to each frame of data and the battery SOC value in each frame of data includes:

[0026] Based on the correspondence between the processed voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, a second curve of the processed voltage difference versus the battery SOC value within the set time period is obtained;

[0027] A second curve segment in which the processed voltage difference in the second curve is greater than a set threshold is determined, and a battery SOC interval corresponding to the second curve segment is determined.

[0028] Optionally, obtaining a second curve showing a change in the processed voltage difference value with the battery SOC value within the set time period based on the correspondence between the processed voltage difference value corresponding to each frame of data and the battery SOC value in each frame of data includes:

[0029] Based on the correspondence between the processed voltage difference value corresponding to each frame of data and the battery SOC value in each frame of data, determining that a minimum value of at least two processed voltage differences corresponding to the same battery SOC value is the processed voltage difference corresponding to the same battery SOC value;

[0030] Based on the processed voltage difference corresponding to each different battery SOC value, a second curve of the processed voltage difference changing with the battery SOC value within the set time period is obtained.

[0031] Optionally, after obtaining the SOC deviation of the battery, the method further includes:

[0032] The SOC deviation of the battery is uploaded to the cloud server.

[0033] Optionally, the set threshold is greater than the difference between the upper limit value of the voltage fluctuation range of the first platform area and the lower limit value of the voltage fluctuation range of the first platform area, and the set threshold is greater than the difference between the upper limit value of the voltage fluctuation range of the second platform area and the lower limit value of the voltage fluctuation range of the second platform area, and the set threshold is less than the absolute value of the difference between the upper limit value of the voltage fluctuation range of the first platform area and the lower limit value of the voltage fluctuation range of the second platform area. The first platform area and the second platform area are two adjacent platform areas in the SOC-OCV curve of the battery.

[0034] Optionally, the SOC-OCV curve of the battery includes a small platform area, a first large platform area and a second large platform area, the SOC value of the first large platform area is greater than the SOC value of the small platform area and less than the SOC value of the second large platform area; the first platform area is one of the first large platform area and the second large platform area, and the second platform area is the other of the first large platform area and the second large platform area.

[0035] A second aspect of an embodiment of the present application provides a battery consistency determination device, wherein the battery includes at least two battery cells, and the device includes:

[0036] a determining unit, configured to determine a voltage difference corresponding to each frame of data, wherein the voltage difference is a difference between a highest cell voltage and a lowest cell voltage in each frame of data;

[0037] The determining unit is further configured to determine a battery SOC interval based on a correspondence between the voltage difference corresponding to each frame of data and the battery SOC in each frame of data, wherein the voltage difference corresponding to the battery SOC interval is greater than a set threshold;

[0038] The determining unit is further configured to determine a difference between an upper limit value of the battery SOC interval and a lower limit value of the battery SOC interval as an SOC deviation of the battery, where the SOC deviation of the battery is used to measure the consistency of the battery.

[0039] The third aspect of an embodiment of the present application provides a server, which includes a first communication module and a processing module. The first communication module is used to communicate with the electric energy device where the battery is located to receive each frame of data, and the processing module is used to execute the step instructions in the first aspect of the embodiment of the present application.

[0040] Optionally, when the SOC deviation is greater than a preset warning threshold, the processing module is further configured to send a warning signal to the electric energy device through the first communication module.

[0041] The fourth aspect of an embodiment of the present application provides an electric energy device, which includes a battery and a second communication module, and the second communication module is used to send each frame of data of the battery to a server, so that the server executes the step instructions in the first aspect of the embodiment of the present application according to each frame of data.

[0042] A fifth aspect of an embodiment of the present application provides an electric energy device, which includes a battery and a processing component, and the processing component is used to execute the step instructions in the first aspect of the embodiment of the present application according to each frame of data of the battery.

[0043] Optionally, the electric energy device includes an alarm component, and the processing component is further configured to trigger the alarm component to issue an alarm message and / or send an alarm prompt message to a third-party device when the SOC deviation is greater than a preset alarm threshold.

[0044] The sixth aspect of an embodiment of the present application provides an electronic device, including a processor and a memory, the memory being used to store a computer program, the computer program including program instructions, and the processor being configured to call the program instructions and execute the step instructions as in the first aspect of the embodiment of the present application.

[0045] The seventh aspect of the embodiments of the present application provides a computer-readable storage medium, wherein the above-mentioned computer-readable storage medium stores a computer program for electronic data exchange, wherein the above-mentioned computer program enables the computer to execute some or all of the steps described in the first aspect of the embodiments of the present application.

[0046] An eighth aspect of the present application provides a computer program product, wherein the computer program product includes a computer program that is operable to cause a computer to perform some or all of the steps described in the first aspect of the present application. The computer program product may be a software installation package.

[0047] A ninth aspect of the present invention provides a processor configured to call program instructions and execute the steps described in the first aspect of the present invention. The processor may include any one of a chip, an integrated circuit, a microprocessor unit (MCU), and a computer terminal.

[0048] In an embodiment of the present application, the voltage difference corresponding to each frame of data is determined, and the voltage difference is the difference between the highest cell voltage and the lowest cell voltage in each frame of data; based on the corresponding relationship between the voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, the battery SOC interval is determined, and the voltage difference corresponding to the battery SOC interval is greater than a set threshold; the difference between the upper limit value of the battery SOC interval and the lower limit value of the battery SOC interval is determined as the SOC deviation of the battery, and the SOC deviation of the battery is used to measure the consistency of the battery. In an embodiment of the present application, based on the corresponding relationship between the voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, the battery SOC interval is determined, and the difference between the upper limit value of the battery SOC interval and the lower limit value of the battery SOC interval is determined as the SOC deviation of the battery. In the process of determining the SOC deviation of the battery, only the battery SOC value needs to be used, and there is no need to calculate the SOC value of each cell. This can reduce the amount of calculation for determining the SOC deviation, thereby quickly determining the consistency of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0050] FIG1 is a schematic diagram of an SOC-OCV curve of a lithium iron phosphate battery provided in an embodiment of the present application;

[0051] FIG2 is a flow chart of a method for determining battery consistency according to an embodiment of the present application;

[0052] FIG3 is a schematic diagram of a corresponding relationship between a voltage difference corresponding to each frame of data and a battery SOC value in each frame of data provided by an embodiment of the present application;

[0053] FIG4 is a flow chart of another method for determining battery consistency provided in an embodiment of the present application;

[0054] FIG5 is a schematic diagram of a first curve showing a voltage difference varying with time provided by an embodiment of the present application;

[0055] FIG6 is a schematic diagram of a second curve showing a voltage difference varying with a battery SOC value provided by an embodiment of the present application;

[0056] FIG7 is a schematic diagram of a specific flow chart of a method for determining battery consistency provided in an embodiment of the present application;

[0057] FIG8 is a schematic structural diagram of a battery consistency determination device provided in an embodiment of the present application;

[0058] FIG9 is a schematic structural diagram of an electronic device provided in an embodiment of the present application;

[0059] FIG10 is a schematic structural diagram of a server provided in an embodiment of the present application;

[0060] FIG11 is a schematic structural diagram of an electric energy device provided in an embodiment of the present application;

[0061] FIG12 is a schematic structural diagram of an electric energy device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0062] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0063] The terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0064] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0065] In electric vehicles, to accurately determine the SOC of a battery cell, a state of charge (SOC)-open circuit voltage (OCV) curve is typically used. By sampling the cell's open circuit voltage, the cell's SOC is determined based on the OCV-SOC mapping relationship in the SOC-OCV curve. The SOC-OCV curve, also known as the OCV curve, is often referred to as the OCV curve.

[0066] Due to its own electrochemical properties, lithium iron phosphate (chemical formula LiFePO4, abbreviated as LFP) batteries have a platform area in their SOC-OCV, which makes it very difficult to accurately estimate the charge state of its individual cells. This property also makes lithium iron phosphate batteries often suffer from consistency problems. In order to more effectively manage and maintain the battery system, it is necessary to detect the consistency problems of the cells in a timely manner. At present, the detection method of the consistency problem of the battery cells is mainly caused by the SOC deviation of the battery cells. Usually, the voltage inflection point on the SOC-OCV curve is found, and the SOC deviation of the battery is obtained by calculating the difference in the charge state of each battery cell at the inflection point. The current method of calculating the SOC deviation requires calculating the charge state of each battery cell at the inflection point, which is computationally intensive.

[0067] The SOC deviation calculation algorithm of the embodiment of the present application determines the battery SOC range based on the correspondence between the voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, and determines that the difference between the upper limit value of the battery SOC range and the lower limit value of the battery SOC range is the SOC deviation of the battery. Only the battery SOC value is used, and there is no need to calculate the SOC value of each battery cell. The amount of calculation for determining the SOC deviation can be reduced, thereby quickly determining the consistency of the battery.

[0068] Please refer to Figure 1, which is a schematic diagram of a SOC-OCV curve for a lithium iron phosphate battery provided in an embodiment of the present application. As shown in Figure 1, the horizontal axis represents the SOC value, and the vertical axis represents the open circuit voltage (OCV) value. As can be seen from Figure 1, once the open circuit voltage of the battery cell is obtained, the corresponding SOC value can be obtained based on the SOC-OCV curve.

[0069] As shown in Figure 1, the SOC-OCV curve of lithium iron phosphate (LFP) batteries is nonlinear, with a small plateau and two large plateaus. If the cell with the highest state of charge (SOC) and the cell with the lowest state of charge are both within the same plateau, the voltage difference between the voltage of the cell with the highest state of charge and the voltage of the cell with the lowest state of charge will be very small. However, as the electric device discharges or charges, the cell with the highest state of charge and the cell with the lowest state of charge will sequentially pass through the inflection points (inflection point 2 in Figure 1) of the two large plateaus (large plateaus 1 and large plateaus 2 as shown in Figure 1). By calculating the change in battery SOC when the cell with the highest state of charge is on the high voltage platform and the cell with the lowest state of charge is on the low voltage platform, the consistency gap between the cells can be calculated. Figure 1 contains two inflection points: inflection point 1 and inflection point 2. Inflection point 1 is the inflection point with a lower SOC, and inflection point 2 is the inflection point with a higher SOC.

[0070] The electric device may be a device driven by electric energy, for example, a vehicle, an aircraft, a ship, or an energy storage cabinet.

[0071] It should be noted that FIG1 is only a possible example of an SOC-OCV curve. The SOC-OCV curve may also use OCV as the abscissa and the SOC value as the ordinate.

[0072] Please refer to Figure 2, which is a flow chart of a method for determining battery consistency according to an embodiment of the present application. As shown in Figure 2, the method for determining battery consistency includes the following steps.

[0073] 201 , the electronic device determines a voltage difference corresponding to each frame of data, where the voltage difference is the difference between the highest cell voltage and the lowest cell voltage in each frame of data.

[0074] The electronic device can be any device with computing and communication capabilities. For example, the electronic device can be a cloud server. The electronic device can be a cloud server used to calculate battery SOC deviation.

[0075] In the embodiment of the present application, the voltage difference is equal to the highest cell voltage minus the lowest cell voltage in each frame of data.

[0076] Each frame of data is the status data of the battery sampled in each sampling period. The battery may include at least two battery cells, and the status data of the battery may include: the voltage of the at least two battery cells, the cell numbers of the at least two battery cells, the battery SOC and other data. For example, if the sampling period is 30 seconds, each frame of data includes the voltage of at least two battery cells of the battery sampled within 30 seconds, the cell numbers of at least two battery cells, the battery SOC and other data. Frame data can exist in the form of a data frame, or in any form that can carry the status data of the battery, such as a data sequence, and is not limited in the embodiments of the present application.

[0077] Each frame of data may include the highest cell voltage, the lowest cell voltage, and the battery SOC. The battery may be composed of at least two cells connected in series. The highest cell voltage of each frame of data is the voltage of the cell with the highest cell voltage sampled from all the cells of the battery within the sampling period of each frame of data (for example, the sampling period may be 30 seconds). The lowest cell voltage of each frame of data is the voltage of the cell with the lowest cell voltage sampled from all the cells of the battery within the sampling period of each frame of data.

[0078] For example, a battery may include 120 battery cells, and each frame of data may include the voltage of the battery cell with the highest voltage (highest battery cell voltage), the voltage of the battery cell with the lowest voltage (lowest battery cell voltage) and the battery SOC among the 120 battery cells sampled within the sampling period corresponding to the frame of data.

[0079] It should be noted that battery SOC is different from cell SOC. Battery SOC is the SOC of the entire battery, while cell SOC is the SOC of the cell itself.

[0080] Each frame of data may further include the cell number of the battery cell with the highest voltage and the cell number of the battery cell with the lowest voltage among the multiple battery cells.

[0081] Optionally, each frame of data is any pre-processed frame data of the battery in a set time period.

[0082] In the embodiment of the present application, each frame of data in step 201 is pre-processed frame data.

[0083] The electronic device may obtain all original frame data uploaded by the same vehicle during a set period, and process each original frame data uploaded by the same vehicle during the set period to obtain each frame data in step 201 .

[0084] For example, the set time period is 72 hours. The same vehicle can periodically sample the original state data of the battery of the vehicle according to the set sampling period, and report the original state data of the battery to the electronic device in the form of original frame data. The set sampling period can be set in advance, and the set sampling period can be set to any value within 1 to 100 seconds. For example, it can be set to 30 seconds. Then, within the set time period of 72 hours, a total of 8640 (72*60*2) original frame data reported by the same vehicle can be received. The original state data of the battery may include: the original voltage of at least two cells of the battery, the original cell number of the at least two cells, the original SOC of the battery and other data.

[0085] Optionally, the set time period includes at least one of a discharge period, an AC charging period, and a DC charging period.

[0086] Optionally, the set period includes at least one of a discharge period and an AC charging period.

[0087] The embodiments of the present application can calculate the battery SOC deviation based on the frame data reported by the battery during the discharge period, the battery SOC deviation can also be calculated based on the frame data reported by the battery during the AC charging phase, and the battery SOC deviation can also be calculated based on the frame data reported by the battery during the discharge period and the AC charging phase. The battery consistency determination method of the embodiments of the present application can be used in discharge conditions and can also be used in AC charging conditions.

[0088] The present embodiment can be applied to predict inflection points and calculate SOC deviations during discharge or AC charging periods. Since every vehicle has a discharge period, sufficient frame data is guaranteed. The battery consistency determination method of the present embodiment can accurately calculate the SOC deviations of all vehicles.

[0089] The set period may include data during the discharge period and the AC charging period when the battery SOC is within a set SOC value range. The set SOC value range may be pre-set. The set SOC value range may include a portion of the large platform area 1 in Figure 1, a portion of the large platform area 2, and the inflection point 2 between the large platform area 1 and the large platform area 2. For example, the set SOC value range may be 50% to 90%. On the one hand, within the set SOC value range, the data occurs frequently, so there is sufficient data to calculate the SOC deviation, and the electronic device can quickly obtain the calculation result of the SOC deviation. On the other hand, in this set SOC value interval, there is only one frequently occurring inflection point (inflection point 2 as shown in Figure 1). When calculating the SOC deviation, it will not be interfered with by another inflection point (inflection point 1 as shown in Figure 1). In addition, compared with the shorter duration of the small platform area of ​​the data near inflection point 1, the duration of large platform areas 1 and 2 near inflection point 2 in this set SOC value interval is relatively longer. The amount of data in this set SOC value interval is greater, the credibility of the data is relatively higher, and the accuracy of the SOC deviation calculated based on the data in this set SOC value interval is relatively higher. Therefore, the SOC deviation can be calculated quickly and accurately.

[0090] When the battery is charging, when the cell with the highest voltage is fully charged, all other cells will not be charged anymore (even the cell with the lowest voltage will not be charged anymore). Therefore, the SOC of the cell with the lowest voltage may be above 90%, but not 100%. Data above 90% is not reliable. There will be a large voltage difference.

[0091] In addition, 50% to 90% is a very high frequency data. In actual charging and discharging conditions, the probability of encountering inflection point 1 in Figure 1 is lower than the probability of encountering inflection point 2, so the data segment containing the high probability inflection point 2 is selected.

[0092] Optionally, the preprocessing includes at least one of: sorting by time, removing null values, removing duplicate data, removing invalid values, removing sampling outliers, and removing data that does not meet the algorithm working conditions.

[0093] Sorting by time: Each raw data frame uploaded by the same vehicle contains the sampling time point of the raw data frame. You can sort the raw data frames by the sampling time point of each raw data frame.

[0094] Remove null values: Some fields in the original data frame may have no data. For example, if the value of the field corresponding to the battery SOC is "None" or "empty", it means that the original data frame has null values. The original data frame with null values ​​can be removed.

[0095] Remove duplicate data: If the same data appears twice or more in the original data frame, remove the duplicate data and keep only one data.

[0096] Remove invalid values: Invalid values ​​are data that clearly contradicts the facts. For example, the highest cell voltage is 2.4V and the lowest cell voltage is 3.2V. These invalid raw data frames can be removed.

[0097] Remove sampling outliers: Sampling outliers are values ​​that are outside the parameter range. For example, if the SOC value range is 0-100%, if the SOC value in the reported raw data frame is -10, it is a sampling outlier and the raw data frame with the sampling outlier can be removed.

[0098] Removing data that does not conform to the algorithm working conditions: For example, the DC charging period is not applicable to the battery consistency determination method of the embodiment of the present application, and the data of the DC charging period can be removed.

[0099] In the embodiment of the present application, the original data frame can be preprocessed to obtain frame data.

[0100] 202 , the electronic device determines a battery SOC interval based on a correspondence between a voltage difference corresponding to each frame of data and a battery SOC value in each frame of data, wherein the voltage difference corresponding to the battery SOC interval is greater than a set threshold.

[0101] In an embodiment of the present application, each frame of data has a battery SOC value, and each frame of data corresponds to a voltage difference value. According to the voltage difference value corresponding to each frame of data and the battery SOC value in each frame of data, a corresponding relationship between the voltage difference value corresponding to each frame of data and the battery SOC value in each frame of data can be established. The corresponding relationship may include a relationship pair set, the relationship pair set includes multiple relationship pairs, each relationship pair includes a voltage difference value and a corresponding battery SOC value. The relationship pair set can be stored in a memory (e.g., a non-volatile memory) of an electronic device. A target relationship pair set whose voltage difference value is greater than a set threshold value can be determined from the relationship pair set, and the interval of the SOC value in the target relationship pair set is determined, which is the battery SOC interval.

[0102] For example, within a set time period, there are 10,000 frames of data. Based on the voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, a corresponding relationship between the voltage difference corresponding to each frame of data and the battery SOC value in each frame of data can be established. For example, the voltage difference corresponding to different battery SOC values ​​within the battery SOC value range of 50% to 90% can be obtained, and the SOC range corresponding to the voltage difference greater than the set threshold can be determined.

[0103] Please refer to Figure 3, which is a schematic diagram illustrating the relationship between the voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, provided by an embodiment of the present application. As shown in Figure 3, the horizontal axis represents the battery SOC value, and the vertical axis represents the voltage difference. The SOC range corresponding to a voltage difference greater than a set threshold can be determined. As shown in Figure 3, the lower limit of this SOC range is SOC1, and the upper limit of this SOC range is SOC2.

[0104] 203 , the electronic device determines the difference between the upper limit value of the battery SOC interval and the lower limit value of the battery SOC interval as the battery SOC deviation, and the battery SOC deviation is used to measure the consistency of the battery.

[0105] In the embodiment of the present application, the lower limit of the SOC interval can be understood as the battery SOC value when the battery cell with the highest voltage passes through the inflection point (for example, inflection point 2 between Figure 1) (for example, it can be recorded as SOC1). The upper limit of the SOC interval can be understood as the battery SOC value when the battery cell with the lowest voltage passes through the inflection point (for example, inflection point 2 between Figure 1) (for example, it can be recorded as SOC2). The battery SOC deviation can be obtained by subtracting SOC2 from SOC1.

[0106] In the embodiment of the present application, the absolute value of the upper limit value of the battery SOC interval and the lower limit value of the battery SOC interval can be used as the battery SOC deviation.

[0107] The battery's SOC deviation is used to measure battery consistency and is an important criterion for measuring battery consistency. Generally speaking, the smaller the battery's SOC deviation, the better the battery's consistency, and the larger the battery's SOC deviation, the worse the battery's consistency.

[0108] In an embodiment of the present application, the battery SOC interval is determined based on the correspondence between the voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, and the difference between the upper limit value of the battery SOC interval and the lower limit value of the battery SOC interval is determined to be the SOC deviation of the battery. In the process of determining the SOC deviation of the battery, only the battery SOC value needs to be used, and there is no need to calculate the SOC value of each battery cell. The amount of calculation for determining the SOC deviation can be reduced, thereby quickly determining the consistency of the battery.

[0109] Please refer to Figure 4, which is a flow chart of another method for determining battery consistency provided in an embodiment of the present application. As shown in Figure 4, the method for determining battery consistency includes the following steps.

[0110] 401 , the electronic device determines a voltage difference corresponding to each frame of data, where the voltage difference is the difference between the highest cell voltage and the lowest cell voltage in each frame of data.

[0111] 402 , the electronic device performs filtering processing on the voltage difference value corresponding to each frame of data to obtain a processed voltage difference value corresponding to each frame of data.

[0112] In an embodiment of the present application, since the highest cell voltage and the lowest cell voltage in each frame of data are sampled within the same sampling period, within the sampling period (for example, the sampling period can be set to 30 seconds), the voltage sampling time points of each cell will have certain differences. If, within the sampling period, the battery is discharged rapidly (for example, an electric vehicle is climbing a slope) or charged (for example, an electric vehicle is braking suddenly), if the voltage sampling time points of the cell are greatly different (if the sampling period is 30 seconds, the maximum difference is also 30 seconds), then the voltage difference between the highest cell voltage and the lowest cell voltage in each frame of data and the voltage difference between the true value will have a certain deviation.

[0113] The embodiment of the present application can filter the voltage difference corresponding to the frame data to obtain the processed voltage difference corresponding to each frame data, so that the processed voltage difference corresponding to each frame data can be closer to the actual voltage difference, thereby improving the calculation accuracy of the SOC deviation.

[0114] Optionally, step 402 may specifically include the following steps:

[0115] (11) The electronic device determines a set of credible voltage difference values ​​among the voltage difference values ​​corresponding to each frame of data within the set time period;

[0116] (12) The electronic device performs polynomial fitting based on the set of credible voltage difference values ​​to obtain a fitted voltage difference value corresponding to each frame of data within the set time period;

[0117] (13) The electronic device performs filtering processing on the fitted voltage difference value corresponding to each frame of data within the set time period to obtain a processed voltage difference value corresponding to each frame of data.

[0118] In an embodiment of the present application, the electronic device can determine a set of credible voltage difference values ​​in the voltage difference values ​​corresponding to each frame of data within a set time period. Since the sampling time of each battery cell may be different, there will be a certain deviation between the voltage difference value of the highest battery cell voltage and the lowest battery cell voltage in each frame of data and the voltage difference value of the true value. A set of credible voltage difference values ​​in the voltage difference values ​​corresponding to each frame of data within a set time period can be found. Polynomial fitting can be performed based on the credible voltage difference value set to obtain the fitted voltage difference value corresponding to each frame of data within the set time period, and the fitted voltage difference value corresponding to each frame of data within the set time period can be filtered to obtain the processed voltage difference value corresponding to each frame of data.

[0119] For example, within a certain sampling period, for example, cell 1 and cell 2 are the cell with the highest voltage section and the cell with the lowest voltage section, respectively, and the voltages of these two cells may not be sampled at the same time. At the inflection point, there is a minimum value theory, that is, if the sampling time of the cell with the highest voltage section and the cell with the lowest voltage section are different, then the voltage difference calculated based on the voltage of the cell with the highest voltage section and the voltage of the cell with the lowest voltage section will have a high probability of being larger than the actual voltage difference. Based on this minimum value theory, the embodiment of the present application can increase the credibility of the credible voltage difference value set by selecting the smaller voltage difference value in the voltage difference value corresponding to each frame of data in the set time period and in the inflection point area as the credible voltage difference value set.

[0120] The minimum value theory can be illustrated by an example. Please refer to Table 1, which is a table of the actual voltage difference and the sampled and calculated voltage difference of three battery cells provided in an embodiment of the present application.

[0121] Table 1

[0122] Among them, the voltage difference calculated by sampling is the difference between the voltage of the cell with the highest voltage among the three cells and the voltage of the cell with the lowest voltage. The first sampling time point, the second sampling time point, and the third sampling time point are three possible sampling time points within the sampling period, and these three sampling time points are different. As shown in Table 1, the probability of being less than 2 is 7 / 27, which is a small probability, and the probability of being greater than 2 is 11 / 27, which is a relatively large probability. The probability that the voltage difference calculated by sampling is greater than the actual voltage difference is greater than the probability that the voltage difference calculated by sampling is less than the actual voltage difference. Table 1 is just an example. In actual battery products, the number of cells in the battery is much greater than 3, so that the probability that the voltage difference calculated by sampling is greater than the actual voltage difference is much greater than the probability that the voltage difference calculated by sampling is less than the actual voltage difference.

[0123] The electronic device can perform polynomial fitting based on the trusted voltage difference value set to obtain a fitted voltage difference value corresponding to each frame of data within the set time period. In the trusted voltage difference value set, each trusted voltage difference value corresponds to a frame of data, and each frame of data carries a sampling time point to indicate the sampling time of the frame of data. The sampling time of the frame of data can be a time point within the sampling period of the frame of data. In the trusted voltage difference value set, each trusted voltage difference value corresponds to a sampling time point, and each trusted voltage difference value and the corresponding sampling time point can constitute a trusted data point set.

[0124] The embodiment of the present application can use polynomial regression to perform polynomial fitting. For example, the polynomial can be set to F(t) = at n +btn-1 +…+C. Where n is the number of terms in the polynomial, and a, b, and c are the parameters to be fitted. t is time, which can be the sampling time point of each frame of data. F(t) is the fitted polynomial, and F(t) represents the fitted voltage difference at different time points. F(t) can be a fitting curve with time as the horizontal axis and the fitted voltage difference as the vertical axis. The polynomial curve F(t) can be made to pass through all the credible data points in the credible data point set, and then the loss of F(t) can be minimized to obtain a fitted polynomial curve. It should be noted that the number of credible data points in the credible data point set must be greater than n in order to fit the polynomial curve.

[0125] The electronic device may filter the fitted voltage difference corresponding to each frame of data within the set time period to obtain a processed voltage difference corresponding to each frame of data. After obtaining the fitted polynomial curve, the fitted voltage difference corresponding to each time point may be obtained based on the fitted polynomial curve, thereby obtaining the fitted voltage difference corresponding to each frame of data within the set time period.

[0126] Since there is a minimum value theory at the inflection point, that is, if the sampling time of the battery cell with the highest voltage section and the battery cell with the lowest voltage section are different, then the voltage difference calculated based on the voltage of the battery cell with the highest voltage section and the voltage of the battery cell with the lowest voltage section will have a high probability of being larger than the actual voltage difference. However, there is also a small probability that the voltage difference calculated based on the voltage of the battery cell with the highest voltage section and the voltage of the battery cell with the lowest voltage section may be smaller than the actual voltage difference. This will cause a small number of abnormal values ​​in the credible voltage difference set. In order to avoid the influence of these abnormal values, the electronic device can filter the fitted voltage difference corresponding to each frame of data within the set time period to obtain the processed voltage difference corresponding to each frame of data, so that the processed voltage difference corresponding to each frame of data is closer to the actual voltage difference. Exemplarily, a filtering algorithm can be used to filter the fitted voltage difference corresponding to each frame of data within the set time period to filter out noise (i.e., remove abnormal values ​​in the fitted voltage difference) to obtain the processed voltage difference corresponding to each frame of data. For example, the filtering algorithm can be a Butterworth low-pass filtering algorithm. The filter used in this filtering algorithm can use a finite impulse response (FIR) filter. An FIR filter is a digital filter that performs convolution in the time domain and can filter directly in the time domain. This filtering algorithm can also convert time domain data into the frequency domain and perform low-pass filtering in the frequency domain.

[0127] Optionally, step (11) may specifically include the following steps:

[0128] (111) The electronic device obtains a first curve of the voltage difference corresponding to each frame of data over time within the set time period based on the correspondence between the voltage difference corresponding to each frame of data and the sampling time point corresponding to each frame of data;

[0129] (112) The electronic device determines a first curve segment in the first curve in which the voltage difference is greater than a first threshold value, determines a lower envelope area in the first curve segment, and determines the smallest N voltage difference values ​​in the lower envelope area as a set of credible voltage difference values ​​in the voltage difference values ​​corresponding to each frame of data in the set time period, where N is an integer greater than or equal to 2.

[0130] Step (111) and step (112) are methods for determining a set of credible voltage difference values.

[0131] Based on the above minimum value theory, at the inflection point, if the sampling times of the battery cell with the highest voltage section and the battery cell with the lowest voltage section are different, then the voltage difference calculated based on the voltage of the battery cell with the highest voltage section and the voltage of the battery cell with the lowest voltage section will have a high probability of being larger than the actual voltage difference. Because the voltage difference at the inflection point is large, a first threshold can be used to select the first curve segment with the largest voltage difference, determine the lower envelope region of the first curve segment, and determine the smallest N voltage differences in the lower envelope region as the credible voltage difference value set among the voltage differences corresponding to each frame of data within the set time period.

[0132] Optionally, the first curve does not represent a real curve, but rather a correspondence between a voltage difference and a time point corresponding to each frame of data within a set period of time.

[0133] The lower envelope region of the first curve segment refers to the adjacent downward trend region and upward trend region within the first curve segment. A downward trend region is a region where the decline exceeds a second threshold, and an upward trend region is a region where the rise exceeds the second threshold. The second threshold can be pre-set. The lower envelope region includes adjacent downward trend regions and upward trend regions.

[0134] The first threshold can be pre-set. The first threshold is greater than the difference between the upper limit of the voltage fluctuation range of the first platform region and the lower limit of the voltage fluctuation range of the first platform region, and greater than the difference between the upper limit of the voltage fluctuation range of the second platform region and the lower limit of the voltage fluctuation range of the second platform region, and less than the absolute value of the difference between the upper limit of the voltage fluctuation range of the first platform region and the lower limit of the voltage fluctuation range of the second platform region. The first platform region and the second platform region are two adjacent platform regions in the SOC-OCV curve of the battery, and the upper limit of the voltage fluctuation range of the first platform region is less than the lower limit of the voltage fluctuation range of the second platform region. For example, the first platform region can be large platform region 1 in the SOC-OCV curve of Figure 1, and the second platform region can be large platform region 2 in the SOC-OCV curve of Figure 1. For example, in the first platform region, if the voltage of the battery cell fluctuates between 3.295 and 3.305V, in the second platform region, if the voltage of the battery cell fluctuates between 3.345 and 3.355V. The first threshold value may be set to a value greater than 10 mV and less than 40 mV. For example, the first threshold value may be set to 25 mV.

[0135] Please refer to Figure 5, which is a schematic diagram of a first curve showing the variation of voltage difference over time, provided in an embodiment of the present application. As shown in Figure 5, the first curve shows the variation of voltage difference over time for each frame of data within a set time period. The horizontal axis represents time, and the vertical axis represents voltage difference. As this first curve changes over time, the voltage difference varies within a range of 0 to 50 mV. It should be noted that this first curve is derived from multiple frames of data and is composed of multiple discrete data points. The time on the horizontal axis of this first curve is a discrete value, namely, the sampling time point of each frame of data. The voltage difference on the vertical axis of the first curve is also a discrete value. The bold curve in Figure 5 represents the first curve segment in the first curve where the voltage difference exceeds a first threshold. For example, the first threshold in Figure 5 is 25 mV. As can be seen from this first curve segment, there is a lower envelope region within which the voltage difference is relatively small. The smallest N voltage difference values ​​among all discrete data points in the lower envelope region can be determined as a set of credible voltage difference values. N can be greater than the number of terms in the polynomial fit. N is greater than the number of terms in the polynomial fit, n.

[0136] 403 , the electronic device determines a battery SOC interval based on a correspondence between the processed voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, where the processed voltage difference corresponding to the battery SOC interval is greater than a set threshold.

[0137] In an embodiment of the present application, in an embodiment of the present application, there is a battery SOC value in each frame of data, and each frame of data corresponds to a processed voltage difference value. According to the processed voltage difference value corresponding to each frame of data and the battery SOC value in each frame of data, a corresponding relationship between the processed voltage difference value corresponding to each frame of data and the battery SOC value in each frame of data can be established. The corresponding relationship may include a relationship pair set, the relationship pair set includes multiple relationship pairs, each relationship pair includes a processed voltage difference value and a corresponding battery SOC value. The relationship pair set can be stored in a memory (e.g., a non-volatile memory) of an electronic device. A target relationship pair set in which the processed voltage difference value is greater than a set threshold value can be determined from the relationship pair set, and the interval of the SOC value in the target relationship pair set is determined, which is the battery SOC interval.

[0138] Optionally, step 403 may specifically include the following steps:

[0139] (21) The electronic device obtains a second curve of the processed voltage difference versus the battery SOC value within the set time period based on the correspondence between the processed voltage difference corresponding to each frame of data and the battery SOC value in each frame of data;

[0140] (22) The electronic device determines a second curve segment in which the processed voltage difference in the second curve is greater than a set threshold, and determines a battery SOC interval corresponding to the second curve segment.

[0141] In the embodiment of the present application, there is a one-to-one correspondence between the processed voltage difference corresponding to each frame of data and the battery SOC value in each frame of data. Based on this correspondence, a second curve showing the processed voltage difference changing with the battery SOC value within a set period of time can be obtained.

[0142] Optionally, the second curve is not limited to being represented in the form of a real curve, and may also be a corresponding relationship or functional relationship between the processed voltage difference and the battery SOC value within a set time period.

[0143] Please refer to Figure 6, which is a schematic diagram of a second curve of a voltage difference as a function of the battery SOC value provided in an embodiment of the present application. As shown in Figure 6, the second curve of the voltage difference as a function of the battery SOC value after processing within a set time period, the horizontal axis is the battery SOC value, and the vertical axis is the voltage difference. As the battery SOC value changes, the voltage difference of the second curve changes within the range of 0 to 50mV. It should be noted that the second curve is obtained based on multiple frames of data, and the second curve is composed of multiple discrete data points. The time of the horizontal axis of the second curve is a discrete value, that is, the SOC value of each frame of data. The voltage difference of the vertical axis of the second curve is also a discrete value. The bold curve in Figure 6 is the second curve segment in which the voltage difference is greater than the set threshold, such as the set threshold of 25mV in Figure 6. It can be seen from the second curve segment that the SOC interval corresponds to the voltage difference greater than the set threshold.

[0144] Optionally, step (21) may specifically include the following steps:

[0145] (211) The electronic device determines, based on the correspondence between the processed voltage difference value corresponding to each frame of data and the battery SOC value in each frame of data, that the minimum value among at least two processed voltage differences corresponding to the same battery SOC value is the processed voltage difference corresponding to the same battery SOC value;

[0146] (212) The electronic device obtains a second curve of the processed voltage difference value as the battery SOC value changes within the set time period based on the processed voltage difference value corresponding to each different battery SOC value C.

[0147] In the embodiment of the present application, since there is a lot of frame data within the set time period, there may be two or more frames of data with the same battery SOC value (for example, in the discharge condition, the battery SOC value hardly changes while the vehicle is waiting for the traffic light, and the battery SOC values ​​of several consecutive frames of data may be the same). In the process of generating the second curve, only one voltage difference value is needed for the same battery SOC value. In the embodiment of the present application, the minimum value of at least two processed voltage differences corresponding to the same battery SOC value is determined to be the processed voltage difference corresponding to the same battery SOC value, and the value with the smallest voltage difference is selected. Based on the above minimum value theory, the processed voltage difference corresponding to the same battery SOC value can have a higher probability of being close to the true voltage difference. This improves the accuracy of the second curve of the voltage difference changing with the battery SOC value, and further improves the accuracy of the calculation result of the battery SOC deviation.

[0148] Optionally, the set threshold is greater than the difference between the upper limit of the voltage fluctuation range of the first platform area and the lower limit of the voltage fluctuation range of the first platform area, and the set threshold is greater than the difference between the upper limit of the voltage fluctuation range of the second platform area and the lower limit of the voltage fluctuation range of the second platform area, and the set threshold is less than the absolute value of the difference between the upper limit of the voltage fluctuation range of the first platform area and the lower limit of the voltage fluctuation range of the second platform area. The first platform area and the second platform area are two adjacent platform areas in the SOC-OCV curve of the battery, and the upper limit of the voltage fluctuation range of the first platform area is less than the lower limit of the voltage fluctuation range of the second platform area. For example, the first platform area can be the large platform area 1 in the SOC-OCV curve of Figure 1, and the second platform area can be the large platform area 2 in the SOC-OCV curve of Figure 1. For example, in the first platform area, if the voltage of the battery cell fluctuates within 3.295~3.305V, in the second platform area, if the voltage of the battery cell fluctuates within 3.345~3.355V. The threshold value may be set to a value greater than 10 mV and less than 40 mV. For example, the threshold value may be set to 25 mV.

[0149] The set threshold and the first threshold may be set to the same value or different values.

[0150] Optionally, the SOC-OCV curve of the battery includes a small platform area, a first large platform area, and a second large platform area, wherein the SOC value of the first large platform area is greater than the SOC value of the small platform area and less than the SOC value of the second large platform area; the first platform area is one of the first large platform area and the second large platform area, and the second platform area is the other of the first large platform area and the second large platform area. Exemplarily, the first large platform area may be large platform area 1 in the SOC-OCV curve of FIG1 , and the second large platform area may be large platform area 2 in the SOC-OCV curve of FIG1 .

[0151] 404 , the electronic device determines the difference between the upper limit of the battery SOC interval and the lower limit of the battery SOC interval as the battery SOC deviation. The battery SOC deviation is used to measure the consistency of the battery.

[0152] The specific implementation of step 401 and step 404 can refer to the above-mentioned step 201 and step 203, which will not be repeated here.

[0153] Optionally, after executing step 404, the following step (31) may also be executed.

[0154] (31) The electronic device uploads the SOC deviation of the battery to the cloud server.

[0155] In the embodiment of the present application, the SOC deviation calculated by the electronic device can be uploaded in real time to a cloud server for analyzing battery consistency, serving as a data foundation for subsequent development, such as studying the trend of cell consistency changes to determine whether the battery has other problems, such as rapid consistency changes. Other characteristics (such as the lowest and highest cell percentages during the period) can also be uploaded simultaneously as criteria to increase the credibility of battery consistency.

[0156] The electronic device can be a cloud server that calculates the battery SOC deviation. The cloud server that calculates the battery SOC deviation can upload the calculated battery SOC deviation to a cloud server that analyzes battery consistency. The cloud server that calculates the battery SOC deviation and the cloud server that analyzes battery consistency can be different servers.

[0157] Please refer to Figure 7, which is a schematic diagram of a specific flow chart of a method for determining battery consistency provided by an embodiment of the present application. As shown in Figure 7, the method for determining battery consistency includes the following steps.

[0158] 701, the cloud server filters out the battery status sequence information of the target vehicle within the target time.

[0159] There may be multiple battery status sequence information, which may correspond to the above-mentioned original data frames.

[0160] Battery status sequence information may include: vehicle status data, maximum and minimum cell voltage, current, temperature, battery SOC value, maximum and minimum cell count, etc. The vehicle can upload this data to the cloud server after marking the sampling time for subsequent processing.

[0161] At 702 , the cloud server pre-processes the battery status sequence information by sorting by time, removing null values, removing duplicate data, removing invalid values, removing abnormal values, and removing high current conditions.

[0162] Among them, the data uploaded by vehicles can be preprocessed every 24 hours, including sorting by time, removing null values, removing duplicate data, removing invalid values, removing sampling outliers, and deleting data that is not applicable to the algorithm working conditions.

[0163] The data after preprocessing is input into the algorithm. The algorithm mainly calculates the battery SOC value, the maximum cell voltage V max , minimum cell voltage V min , the highest cell number Nmax, the lowest cell number Nmin and other values ​​are filtered and analyzed.

[0164] At 703 , the cloud server obtains a voltage difference based on the difference between the highest cell voltage and the lowest cell voltage, divides the data according to the working conditions to obtain different charging segment data and discharging segment data, calculates the voltage difference lower envelope for the discharging segment data, and performs polynomial regression and Butterworth filtering on the discharging segment data.

[0165] Among them, the highest cell voltage V max Minimum cell voltage V min Take the difference, V diff =V max -V min The V obtained here diff Represents the voltage difference between the battery cell with the highest charge and the battery cell with the lowest charge.

[0166] Since the discharge voltage is unstable, the sampled cell voltage will fluctuate. diff Filtering is performed to remove small sampling errors and different voltage transient responses caused by large currents. First, the lower envelope of the voltage difference is obtained, and polynomial regression is performed on the lower envelope value and interpolated to obtain V env (i.e. the fitting voltage difference mentioned above), and then use Butterworth low-pass filtering to filter V env By filtering out the noise, a smooth pressure difference value V can be obtained. env At this time, the voltage difference between 50% and 90% of the battery SOC value can be used to judge consistency (the voltage above 90% SOC has a large voltage difference, and the SOC below 50% will be affected by the low inflection point, so the data between 50% and 90% SOC is selected).

[0167] 704. The cloud server groups the charging segment data and the discharging segment data according to the SOC and calculates the minimum value of the pressure difference. It calculates the SOC interval in which the continuous pressure difference is greater than the set threshold, obtains the battery's SOC deviation, and counts the highest cell number and the lowest cell number in the data corresponding to the SOC interval.

[0168] In an embodiment of the present application, the data of the entire battery pack SOC between 50% and 90% is grouped with integer SOC (for example, SOC can be divided into 41 groups: 50%, 51%, 52%, ..., 90%) as the index. The grouping function is to find the minimum value, and the original time (number of data frames) is converted into SOC as the variable to obtain the minimum pressure difference corresponding to each integer SOC value.

[0169] The threshold value can be determined by Figure 1. As shown in Figure 1, when the lithium iron phosphate battery is in two different platforms, the voltage difference is above 25mV, so the voltage difference threshold is designed to be 25mV. If the battery cell with the highest power state and the battery cell with the lowest power state are in the same platform at the same time, the voltage difference is greater than 25mV. max -V min The obtained Vdiff As the vehicle charges and discharges, the battery cells with the highest and lowest states of charge will sequentially pass through inflection point 2 between large platform 1 and large platform 2. The SOC1 of the highest voltage cell passing through the inflection point and the SOC2 of the lowest voltage cell passing through the inflection point are recorded. |SOC2-SOC1| is the consistency deviation of the battery cells.

[0170] At 705 , the cloud server uploads the battery SOC deviation, the lowest cell ratio, and the highest cell ratio to the cloud.

[0171] The calculated battery SOC deviation can be uploaded to the cloud server in real time to serve as the data foundation for subsequent development, such as studying the consistency trend of battery cells to determine whether there are other problems such as rapid consistency changes. Other characteristics (such as the lowest and highest cell percentages during the period) are also uploaded as criteria to increase the credibility of consistency.

[0172] The lowest voltage cell ratio refers to the percentage of cells with the lowest voltage in the data corresponding to the SOC range. The highest voltage cell ratio refers to the percentage of cells with the highest voltage in the data corresponding to the SOC range.

[0173] The technical problem addressed by the embodiments of the present application is that the method for calculating the state of charge (SOC) deviation of a battery cell is overly dependent on specific charging phase data. When specific data is missing or only recently available, the traditional algorithm fails or cannot obtain the real-time state of charge deviation of the battery cell. When data quality is poor, such as insufficient synchronization, traditional solutions use data from the AC charging phase and cannot use data from the discharge phase.

[0174] The algorithm of the embodiment of the present application is applicable to different vehicle operating conditions. The algorithm not only uses data including the AC charging segment to calculate the battery's state of charge deviation, but also uses data including the discharge segment to calculate the battery's state of charge deviation, thereby calculating the battery's state of charge deviation more timely.

[0175] The present embodiment can identify the battery's state of charge deviation and, based on the battery's state of charge deviation, determine whether there are other consistency issues (such as abnormal internal resistance and leakage). The present embodiment can calculate the vehicle's battery's state of charge deviation on a cloud server, continuously tracking the battery's consistency status and providing a foundation for trending algorithms.

[0176] The above describes the solution of the embodiment of the present application from the perspective of the execution process of the method side. It is understandable that, in order to realize the above functions, the electronic device includes a hardware structure and / or software module corresponding to the execution of each function. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of each example described in the embodiment provided herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0177] The embodiment of the present application can divide the functional units of the electronic device according to the above method example. For example, each functional unit can be divided according to each function, or two or more functions can be integrated into one processing unit. The above integrated unit can be implemented in the form of hardware or in the form of software functional units. It should be noted that the division of units in the embodiment of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0178] Please refer to FIG8 , which is a schematic diagram of the structure of a battery consistency determination device provided in an embodiment of the present application. The battery includes at least two battery cells. The battery consistency determination device 800 may include a determination unit 801, wherein:

[0179] A determining unit 801 is configured to determine a voltage difference corresponding to each frame of data, where the voltage difference is the difference between the highest cell voltage and the lowest cell voltage in each frame of data;

[0180] The determining unit 801 is further configured to determine a battery SOC interval based on a correspondence between the voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, wherein the voltage difference corresponding to the battery SOC interval is greater than a set threshold;

[0181] The determining unit 801 is further configured to determine a difference between an upper limit value of the battery SOC interval and a lower limit value of the battery SOC interval to obtain an SOC deviation of the battery. The SOC deviation of the battery is used to measure the consistency of the battery.

[0182] Optionally, each frame of data is any pre-processed frame data of the battery in a set time period.

[0183] Optionally, the set time period includes at least one of a discharge period, an AC charging period, and a DC charging period.

[0184] Optionally, the preprocessing includes at least one of: sorting by time, removing null values, removing duplicate data, removing invalid values, removing sampling outliers, and removing data that does not meet the algorithm working conditions.

[0185] Optionally, the battery consistency determination device 800 may further include a filtering unit 802;

[0186] A filtering unit 802 is configured to filter the voltage difference corresponding to each frame of data to obtain a processed voltage difference corresponding to each frame of data;

[0187] The determination unit 801 determines the battery SOC interval based on the correspondence between the voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, and the voltage difference corresponding to the battery SOC interval is greater than the set threshold, including: determining the battery SOC interval based on the correspondence between the processed voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, and the processed voltage difference corresponding to the battery SOC interval is greater than the set threshold.

[0188] Optionally, the filtering unit 802 performs filtering processing on the voltage difference value corresponding to each frame of data to obtain the processed voltage difference value corresponding to each frame of data, including: determining a set of credible voltage difference values ​​among the voltage difference values ​​corresponding to each frame of data within the set time period; performing polynomial fitting based on the credible voltage difference value set to obtain a fitted voltage difference value corresponding to each frame of data within the set time period; and filtering the fitted voltage difference value corresponding to each frame of data within the set time period to obtain the processed voltage difference value corresponding to each frame of data.

[0189] Optionally, the filtering unit 802 determines a set of credible voltage difference values ​​among the voltage difference values ​​corresponding to each frame of data within the set time period, including: obtaining a first curve showing the change of the voltage difference value corresponding to each frame of data within the set time period over time based on the correspondence between the voltage difference value corresponding to each frame of data and the sampling time point corresponding to each frame of data; determining a first curve segment in the first curve in which the voltage difference value is greater than a first threshold value, determining a lower envelope area in the first curve segment, and determining the smallest N voltage difference values ​​in the lower envelope area as a set of credible voltage difference values ​​among the voltage difference values ​​corresponding to each frame of data within the set time period, where N is an integer greater than or equal to 2.

[0190] Optionally, the determination unit 801 determines the battery SOC interval based on the correspondence between the processed voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, including: obtaining a second curve in which the processed voltage difference changes with the battery SOC value within the set time period based on the correspondence between the processed voltage difference corresponding to each frame of data and the battery SOC value in each frame of data; determining a second curve segment in the second curve in which the processed voltage difference is greater than a set threshold, and determining the battery SOC interval corresponding to the second curve segment.

[0191] Optionally, the determination unit 801 obtains a second curve of the processed voltage difference value changing with the battery SOC value within the set time period based on the correspondence between the processed voltage difference value corresponding to each frame of data and the battery SOC value in each frame of data, including: determining that the minimum value of at least two processed voltage difference values ​​corresponding to the same battery SOC value is the processed voltage difference corresponding to the same battery SOC value based on the correspondence between the processed voltage difference value corresponding to each frame of data and the battery SOC value in each frame of data; and obtaining a second curve of the processed voltage difference value changing with the battery SOC value within the set time period based on the processed voltage difference corresponding to each different battery SOC value.

[0192] Optionally, the battery consistency determination device 800 may further include an uploading unit 803;

[0193] The uploading unit 803 is configured to upload the SOC deviation of the battery to a cloud server.

[0194] Optionally, the set threshold is greater than the difference between the upper limit value of the voltage fluctuation range of the first platform area and the lower limit value of the voltage fluctuation range of the first platform area, and the set threshold is greater than the difference between the upper limit value of the voltage fluctuation range of the second platform area and the lower limit value of the voltage fluctuation range of the second platform area, and the set threshold is less than the absolute value of the difference between the upper limit value of the voltage fluctuation range of the first platform area and the lower limit value of the voltage fluctuation range of the second platform area. The first platform area and the second platform area are two adjacent platform areas in the SOC-OCV curve of the battery.

[0195] Optionally, the SOC-OCV curve of the battery includes a small platform area, a first large platform area and a second large platform area, the SOC value of the first large platform area is greater than the SOC value of the small platform area and less than the SOC value of the second large platform area; the first platform area is one of the first large platform area and the second large platform area, and the second platform area is the other of the first large platform area and the second large platform area.

[0196] The determining unit 801 and the filtering unit 802 in the embodiment of the present application may be processors in an electronic device, and the uploading unit 803 may be a communication module in an electronic device.

[0197] In an embodiment of the present application, the battery SOC interval is determined based on the correspondence between the voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, and the difference between the upper limit value of the battery SOC interval and the lower limit value of the battery SOC interval is determined as the SOC deviation of the battery. In the process of determining the SOC deviation of the battery, only the battery SOC value needs to be used, and there is no need to calculate the SOC value of each battery cell. The amount of calculation for determining the SOC deviation can be reduced, thereby quickly determining the consistency of the battery.

[0198] Please refer to Figure 9, which is a structural diagram of an electronic device provided in an embodiment of the present application. As shown in Figure 9, the electronic device 900 includes a processor 901 and a memory 902. The processor 901 and the memory 902 can be connected to each other via a communication bus 903. The communication bus 903 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus or a controller area network (CAN) bus, etc. The communication bus 903 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used in Figure 9, but it does not mean that there is only one bus or one type of bus. The memory 902 is used to store computer programs, and the computer program includes program instructions. The processor 901 is configured to call program instructions, and the above program includes some or all of the steps in the method included in Figures 2 to 7 for executing.

[0199] The processor 901 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the above program.

[0200] The memory 902 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, an optical disc storage (including a compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory may exist independently and be connected to the processor via a bus. The memory may also be integrated with the processor.

[0201] The electronic device 900 may further include a communication module 904, which may be used to upload the battery SOC deviation to a cloud server. The communication module 904 may also be used to receive raw data frames uploaded by the vehicle.

[0202] In an embodiment of the present application, the battery SOC interval is determined based on the correspondence between the voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, and the difference between the upper limit value of the battery SOC interval and the lower limit value of the battery SOC interval is determined as the SOC deviation of the battery. In the process of determining the SOC deviation of the battery, only the battery SOC value needs to be used, and there is no need to calculate the SOC value of each battery cell. The amount of calculation for determining the SOC deviation can be reduced, thereby quickly determining the consistency of the battery.

[0203] Please refer to Figure 10, which is a structural diagram of a server provided in an embodiment of the present application. As shown in Figure 10, the server 1000 includes a first communication module 1001 and a processing module 1002. The first communication module 1001 is used to communicate with the electric energy device where the battery is located to receive each frame of data, and the processing module 1002 is used to execute part or all of the steps of any battery consistency determination method recorded in the above method embodiment.

[0204] The processing module 1002 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the above battery consistency determination method.

[0205] Optionally, when the SOC deviation is greater than a preset warning threshold, the processing module 1002 is further configured to send a warning signal to the electric energy device through the first communication module 1001 .

[0206] Please refer to Figure 11, which is a structural diagram of an electric energy device provided in an embodiment of the present application. As shown in Figure 11, the electric energy device 1100 includes a battery 1101 and a processing component 1102. The processing component 1102 is used to execute part or all of the steps of any battery consistency determination method recorded in the above method embodiment according to each frame of data of the battery 1101.

[0207] The processing component 1102 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the above battery consistency determination method.

[0208] Optionally, the electric energy device includes an alarm component 1103, and the processing component 1102 is further configured to trigger the alarm component 1103 to issue an alarm message and / or send an alarm prompt message to a third-party device when the SOC deviation is greater than a preset alarm threshold.

[0209] Please refer to Figure 12, which is a structural diagram of another electric energy device provided in an embodiment of the present application. As shown in Figure 12, the electric energy device 1200 includes a battery 1202 and a second communication module 1201. The second communication module 1201 is used to send each frame of data of the battery 1202 to the server 1000, so that the server 1000 executes part or all of the steps of any battery consistency determination method recorded in the above method embodiment according to each frame of data.

[0210] An embodiment of the present application also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program for electronic data exchange, and the computer program enables a computer to execute part or all of the steps of any one of the battery consistency determination methods described in the above method embodiments.

[0211] It should be noted that for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that this application is not limited by the order of the actions described, because according to this application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by this application.

[0212] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0213] In the several embodiments provided in this application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0214] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0215] In addition, the functional units in the various embodiments of the application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software program modules.

[0216] If the integrated unit is implemented in the form of a software program module and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a memory, including a number of instructions for enabling a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned memory includes: various media that can store program codes, such as a U disk, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk.

[0217] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable memory, which may include: a flash drive, a read-only memory, a random access memory, a magnetic disk or an optical disk, etc.

[0218] The above is a detailed introduction to the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for those skilled in the art, according to the idea of ​​the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for determining the consistency of a battery, the battery including at least two battery cells, the method comprising: Determining a voltage difference corresponding to each frame of data, the voltage difference being the difference between the highest battery cell voltage and the lowest battery cell voltage in each frame of data (201); Based on the correspondence between the voltage difference corresponding to each frame of data and the state of charge (SOC) value of the battery in each frame of data, determining a battery SOC interval, the voltage difference corresponding to the battery SOC interval being greater than a set threshold (202); Determining the difference between the upper limit value and the lower limit value of the battery SOC interval as the SOC deviation of the battery, the SOC deviation of the battery being used to measure the consistency of the battery (203).

2. The method according to claim 1, wherein each frame of data is any preprocessed frame of data of the battery during a set time period.

3. The method according to claim 2, wherein the set time period includes at least one of a discharge period, an AC charging period, and a DC charging period.

4. The method according to claim 2 or 3, wherein the preprocessing includes: At least one of sorting by time, removing null values, removing duplicate data, removing invalid values, removing sampling outliers, and removing data that does not conform to the algorithm operating conditions.

5. The method according to any one of claims 2 to 4, after determining the voltage difference corresponding to each frame of data, the method further comprising: Performing a filtering process on the voltage difference corresponding to each frame of data to obtain a processed voltage difference corresponding to each frame of data (402); The determining a battery SOC interval based on the correspondence between the voltage difference corresponding to each frame of data and the SOC value of the battery in each frame of data, the voltage difference corresponding to the battery SOC interval being greater than a set threshold, includes: Determining a battery SOC interval based on the correspondence between the processed voltage difference corresponding to each frame of data and the SOC value of the battery in each frame of data, the processed voltage difference corresponding to the battery SOC interval being greater than a set threshold (403).

6. The method according to claim 5, the performing a filtering process on the voltage difference corresponding to each frame of data to obtain a processed voltage difference corresponding to each frame of data, includes: Determining a set of reliable voltage differences among the voltage differences corresponding to each frame of data within the set time period; Performing polynomial fitting based on the set of reliable voltage differences to obtain a fitted voltage difference corresponding to each frame of data within the set time period; Performing a filtering process on the fitted voltage difference corresponding to each frame of data within the set time period to obtain a processed voltage difference corresponding to each frame of data.

7. The method according to claim 6, the determining a set of reliable voltage differences among the voltage differences corresponding to each frame of data within the set time period, includes: Based on the correspondence between the voltage difference corresponding to each frame of data and the sampling time point corresponding to each frame of data, obtaining a first curve of the voltage difference corresponding to each frame of data within the set time period changing with time; Determine the first curve segment in the first curve where the voltage difference is greater than the first threshold, determine the lower envelope region in the first curve segment, and determine the smallest N voltage differences in the lower envelope region as the set of credible voltage differences among the voltage differences corresponding to each frame of data within the set time period, where N is an integer greater than or equal to 2.

8. The method according to any one of claims 5 to 7, wherein determining the battery SOC interval based on the corresponding relationship between the processed voltage difference corresponding to each frame of data and the battery SOC value in each frame of data includes: Based on the corresponding relationship between the processed voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, obtain a second curve of the processed voltage difference varying with the battery SOC value within the set time period; Determine the second curve segment in the second curve where the processed voltage difference is greater than the set threshold, and determine the battery SOC interval corresponding to the second curve segment.

9. The method according to claim 8, wherein obtaining a second curve of the processed voltage difference varying with the battery SOC value within the set time period based on the corresponding relationship between the processed voltage difference corresponding to each frame of data and the battery SOC value in each frame of data includes: Based on the corresponding relationship between the processed voltage difference corresponding to each frame of data and the battery SOC value in each frame of data, determine the minimum value among at least two processed voltage differences corresponding to the same battery SOC value as the processed voltage difference corresponding to the same battery SOC value; Based on the processed voltage differences corresponding to each different battery SOC value, obtain a second curve of the processed voltage difference varying with the battery SOC value within the set time period.

10. The method according to any one of claims 1 to 9, after obtaining the SOC deviation of the battery, the method further includes: Upload the SOC deviation of the battery to the cloud server.

11. The method according to any one of claims 1 to 10, wherein the set threshold is greater than the difference between the upper limit value and the lower limit value of the voltage fluctuation range of the first platform region, and the set threshold is greater than the difference between the upper limit value and the lower limit value of the voltage fluctuation range of the second platform region, and the set threshold is less than the absolute value of the difference between the upper limit value of the voltage fluctuation range of the first platform region and the lower limit value of the voltage fluctuation range of the second platform region, where the first platform region and the second platform region are two adjacent platform regions in the SOC-OCV curve of the battery.

12. The method according to claim 11, wherein the SOC-OCV curve of the battery includes a small platform region, a first large platform region, and a second large platform region, the SOC value of the first large platform region is greater than the SOC value of the small platform region and less than the SOC value of the second large platform region; the first platform region is one of the first large platform region and the second large platform region, and the second platform region is the other of the first large platform region and the second large platform region.

13. A server (1000), characterized in that, The server (1000) includes a first communication module (1001) and a processing module (1002). The first communication module (1001) is used to communicate with the power device (1200) where the battery (1202) is located to receive the per-frame data. The processing module (1002) is used to execute the method according to any one of claims 1 to 12.

14. The server according to claim 13, characterized in that, When the SOC deviation is greater than a preset warning threshold, the processing module (1002) is further used to send a warning signal to the power device (1100) through the first communication module (1001).

15. An electrical energy device (1200), characterized in that, The power device (1200) includes a battery (1202) and a second communication module (1201). The second communication module (1201) is used to send the per-frame data of the battery (1202) to the server (1000) so that the server (1000) executes the method according to any one of claims 1 to 12 based on the per-frame data.

16. An electrical energy device (1100), characterized in that, The power device (1100) includes a battery (1101) and a processing component (1102). The processing component (1102) is used to execute the method according to any one of claims 1 to 12 based on the per-frame data of the battery (1101).

17. The device according to claim 16, characterized in that, The power device includes a warning component (1103). The processing component (1102) is further used to trigger the warning component (1103) to send a warning message and / or send a warning prompt message to a third-party device when the SOC deviation is greater than a preset warning threshold.

18. An electronic device (900) includes a processor (901) and a memory (902). The memory (902) is used to store a computer program. The computer program includes program instructions. The processor (901) is configured to call the program instructions to execute the method according to any one of claims 1 to 12.

19. A computer-readable storage medium stores a computer program. The computer program includes program instructions. When the program instructions are executed by a processor, the processor is caused to execute the method according to any one of claims 1 to 12.

20. A computer program product includes a computer program. The computer program is operable to cause a computer to execute the method according to any one of claims 1 to 12.

21. A processor (901) is configured to call program instructions to execute the method according to any one of claims 1 to 12.

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