Battery pack abnormality warning method and battery pack abnormality warning device

Abstract

The present application relates to a battery pack abnormality warning method and battery pack abnormality warning device, the method comprising: obtaining multiple copies of open-circuit voltage data of battery packs of multiple vehicles; obtaining multiple target state-of-charge differences of all battery cells of the multiple vehicles at different preset times based on the multiple copies of open-circuit voltage data; determining the target state-of-charge difference range of each battery cell based on the distribution of the multiple target state-of-charge differences over time; judging whether the current target state-of-charge difference of the current vehicle is within the target state-of-charge difference range, if the current target state-of-charge difference of the current vehicle is within the target state-of-charge difference range, marking the battery pack of the current vehicle as normal; if the current target state-of-charge difference of the current vehicle is outside the target state-of-charge difference range, issuing a warning of battery pack abnormality of the current vehicle. The present application can determine whether the state of charge at the single cell level is abnormal, thereby improving the safety of the entire vehicle.

Description

Technical Field

[0001] The present application relates to the technical field of battery abnormality warning technology, and in particular to a battery pack abnormality warning method and a battery pack abnormality warning device. Background Art

[0002] With the increasing adoption of new energy vehicles (NEVs), big data technology is showing promising application prospects in this field. Establishing vehicle-level fault risk prediction and early warning systems based on EV operating data from a big data perspective has become a hot topic. Big data platforms enable data collection using multi-dimensional tags. Through data screening, integration, and cleaning, intelligent data organization and analysis can be achieved, enabling diagnosis and early warning of battery system faults.

[0003] In related technologies, battery pack risk prediction and fault identification models developed by different automakers vary due to differences in material systems and battery performance. Currently, entire vehicles only display the battery pack's state of charge (SOC), but are unable to estimate or identify the SOC of individual cells. Consequently, they are unable to more effectively identify abnormal risks in battery packs, leading to frequent fires and low safety standards. Summary of the Invention

[0004] In view of this, the present application proposes a battery pack abnormality warning method and a battery pack abnormality warning device, which can determine whether the charge state at the single cell level is abnormal, more effectively identify the abnormal risks of the battery pack, and improve the safety of the entire vehicle.

[0005] According to one aspect of the present application, a battery pack abnormality warning method is provided, the method comprising: obtaining multiple copies of open-circuit voltage data of battery packs of multiple vehicles, the open-circuit voltage data including the open-circuit voltage of each battery cell in the battery pack; obtaining multiple target state-of-charge differences for all battery cells of the multiple vehicles at different preset times based on the multiple copies of the open-circuit voltage data; determining a target state-of-charge difference range for each battery cell based on the distribution of the multiple target state-of-charge differences over time; judging whether the current target state-of-charge difference of the current vehicle is within the target state-of-charge difference range, and if the current target state-of-charge difference of the current vehicle is within the target state-of-charge difference range, marking the battery pack of the current vehicle as normal; and issuing a warning of battery pack abnormality of the current vehicle if the current target state-of-charge difference of the current vehicle is outside the target state-of-charge difference range.

[0006] According to another aspect of the present application, a battery pack abnormality warning device is provided, which includes a processing unit connected to multiple vehicles, and the processing unit is used to implement the battery pack abnormality warning method.

[0007] By obtaining multiple open-circuit voltage data of battery packs of multiple vehicles, and obtaining multiple target state-of-charge differences of all battery cells of multiple vehicles at different preset times based on the multiple open-circuit voltage data, and then determining the target state-of-charge difference range of each battery cell according to the distribution of the multiple target state-of-charge differences over time, and finally judging whether the current target state-of-charge difference of the current vehicle is within the target state-of-charge difference range, according to various aspects of the present application, it is possible to judge whether the state of charge at the single cell level is abnormal, more effectively identify the abnormal risks of the battery pack, and improve the safety of the entire vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The following detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings will make the technical solutions and other beneficial effects of the present application apparent.

[0009] Figure 1 A flowchart of a battery pack abnormality warning method according to an embodiment of the present application is shown.

[0010] Figure 2 A schematic diagram showing the distribution of target state of charge differences over time according to the present application.

[0011] Figure 3 A schematic diagram showing the first expression of the present application.

[0012] Figure 4 A block diagram of a processing unit according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0013] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0014] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0015] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0016] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, examples of various specific processes and materials are provided in the present application, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials. In some instances, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present application.

[0017] Figure 1 The flowchart of the battery pack abnormality warning method according to the embodiment of the present application is shown. Figure 1 As shown, the battery pack abnormality warning method includes:

[0018] Step S1: Acquire multiple sets of open circuit voltage data of battery packs of multiple vehicles, wherein the open circuit voltage data includes the open circuit voltage of each cell in the battery pack;

[0019] In one embodiment, the vehicle is a complete vehicle, and the battery pack of the vehicle may include multiple single cells. A battery management system (BMS) is electrically connected to each of the cells in the battery pack of the complete vehicle. Multiple vehicles may be connected to a battery pack abnormality warning device via a cloud network. The battery pack abnormality warning device includes a processing unit, which is configured to implement the battery pack abnormality warning method. Optionally, the battery pack abnormality warning device is a cloud-based console, which may be a cloud-based big data platform.

[0020] The open-circuit voltage data of each battery cell includes multiple open-circuit voltages (OCV) at different moments. The open-circuit voltage is the voltage between the positive and negative electrodes of the battery cell when no load is connected. The console can be electrically connected to the battery management system of each vehicle to receive multiple copies of the open-circuit voltage data collected by the battery management system.

[0021] Step S2: obtaining a plurality of target state of charge differences of all battery cells of a plurality of vehicles at different preset times based on the plurality of open circuit voltage data;

[0022] In one embodiment, the state of charge (SOC) of a battery cell represents the ratio of the available capacity of the battery cell to the total capacity, and can be expressed as a percentage. At the same time, the state of charge of the battery cell has a one-to-one correspondence with the open circuit voltage of the battery cell. The preset time can be in days.

[0023] Furthermore, obtaining a plurality of target state of charge differences of all battery cells of a plurality of vehicles at different preset times based on the plurality of open circuit voltage data includes:

[0024] Step S21: obtaining multiple target states of charge of all battery cells of multiple vehicles based on multiple copies of the open circuit voltage data;

[0025] The target state of charge of the battery cell may represent the actual state of charge of the battery cell. In this application, in order to make the target state of charge closer to reality, not only the state of charge when the vehicle is turned off is used, but also the state of charge when the vehicle is started is used.

[0026] Furthermore, obtaining multiple target states of charge of all battery cells of multiple vehicles based on multiple copies of the open circuit voltage data includes:

[0027] Step S211: obtaining the SOC-OCV curve of each of the battery cells of a plurality of vehicles;

[0028] The SOC-OCV curves of the battery cells of multiple vehicles can be obtained in advance through the battery management system.

[0029] Step S212: obtaining a plurality of first states of charge of each of the battery cells when the vehicle is turned off according to the plurality of open circuit voltage data and the SOC-OCV curves of each of the battery cells;

[0030] When the vehicle is turned off and the battery pack cells are not connected to a load, the console can determine the first state of charge corresponding to the different open circuit voltages of each cell based on the static SOC-OCV curve of each cell in the battery management system. The static SOC-OCV curve can be obtained using the open circuit voltage method.

[0031] Step S213: correcting the first states of charge by using ampere-hour integration to obtain a plurality of second states of charge of the battery cells;

[0032] Since the first state of charge obtained by using the static SOC-OCV curve is inconsistent with the actual situation, in order to make the estimation of the state of charge more accurate, the first state of charge can be corrected using the ampere-hour integration method.

[0033] When the vehicle is started, the battery cells of the battery pack are connected to a load. At this time, the ampere-hour integration method is used to correct the first state of charge. The formula of the ampere-hour integration method is as follows:

[0034] SOC t =SOC t-1 -(I×Δt / total cell capacity)×100%

[0035] Where I is the charge and discharge current of the battery cell. When the battery cell is discharging, the direction of the current I is positive, and when the battery cell is charging, the direction of the current I is negative. Δt is the change in time, I×Δt is the change in battery cell capacity in Δt time, SOC t-1 is the second state of charge at time t-1, SOC t is the second state of charge at time t. In practical applications, the current I can be detected by a current sensor of the battery management system, and the detected current I can be sent to the control console for further processing.

[0036] Step S214: determining a plurality of target states of charge for all battery cells of a plurality of vehicles based on a plurality of the first states of charge and a plurality of the second states of charge.

[0037] In one embodiment, the target SOC can be determined by the first SOC and the second SOC. In some embodiments, for a fixed battery cell, a weight coefficient k1 can be assigned to the first SOC, and a weight coefficient k2 can be assigned to the second SOC. The target SOC can then be expressed as k1 × first SOC + k2 × second SOC, where k1 and k2 are both greater than 0 and less than 1, and k1 is greater than k2. For example, k1 is 0.8 and k2 is 0.2.

[0038] Step S22: traversing a plurality of open circuit voltages corresponding to a plurality of target states of charge to obtain a plurality of first open circuit voltage extreme values ​​and a plurality of second open circuit voltage extreme values ​​at different preset times;

[0039] In one embodiment, the first open-circuit voltage extreme value may be the maximum open-circuit voltage of all the battery cells of the plurality of vehicles at the preset time, and the second open-circuit voltage extreme value may be the minimum open-circuit voltage of all the battery cells of the plurality of vehicles at the preset time. Both the first open-circuit voltage extreme value and the second open-circuit voltage extreme value are determined based on the corresponding preset time.

[0040] Step S23: obtaining, by reverse query, a plurality of first reference states of charge corresponding to a plurality of first open-circuit voltage extreme values ​​and a plurality of second reference states of charge corresponding to a plurality of second open-circuit voltage extreme values;

[0041] In one embodiment, the open circuit voltage and target state of charge at different preset times may be stored in the battery pack abnormality warning device in the form of a table. When performing a reverse query, the table containing the open circuit voltage and target state of charge at different preset times can be searched.

[0042] For example, the preset time is in days, and the open circuit voltage and target state of charge of each battery cell obtained every day are multiple. On the first day, the highest open circuit voltage of each battery cell of multiple vehicles is OCV max1 , the corresponding target state of charge is SOC max1 ;The minimum open circuit voltage is OCV min1 , the corresponding target state of charge is SOC min1 On the first day, the highest open circuit voltage of each cell of multiple vehicles was OCV max2 , the corresponding target state of charge is SOC max2 ;The minimum open circuit voltage is OCV min2 , the corresponding target state of charge is SOC min2 At this time, SOC max1 and SOC max2 Both are the first reference state of charge, SOC min1 and SOC min2 Both are second reference state of charge.

[0043] Step S24: determining a plurality of target state-of-charge differences for all battery cells of a plurality of vehicles at different preset times according to a plurality of the first reference states of charge and a plurality of the second states of charge.

[0044] Furthermore, determining a plurality of target state-of-charge differences for all battery cells of a plurality of vehicles at different preset times based on a plurality of the first reference states of charge and a plurality of the second states of charge includes:

[0045] Step S241: adding and averaging the first reference states of charge of all battery cells at the same preset time to obtain a first reference state of charge average value;

[0046] Each battery cell corresponds to a first reference state of charge at the preset time. An average value of the first reference state of charge at the same preset time can be obtained by summing the multiple first reference states of charge of all battery cells at the same preset time and then dividing the sum by the total number of battery cells in the multiple vehicles.

[0047] Step S242: adding and averaging the plurality of second reference states of charge of all battery cells at the same preset time to obtain a second reference state of charge average value;

[0048] Each battery cell corresponds to a second reference state of charge at the preset time. An average value of the second reference state of charge at the same preset time can be obtained by summing the multiple second reference states of charge of all battery cells at the same preset time and then dividing the sum by the total number of battery cells in the multiple vehicles.

[0049] Step S243: Obtaining a target SOC difference for the preset time according to the first reference SOC average value and the second reference SOC average value.

[0050] In one embodiment, the first reference SOC average value and the second reference SOC average value may be subtracted and the absolute value taken to obtain the target SOC difference for the preset time. Since there are multiple preset time periods, each preset time period may correspond to a target SOC difference, and therefore there may also be multiple target SOC differences.

[0051] Step S3: determining a target state of charge difference range for each of the battery cells according to a distribution of the target state of charge differences over time;

[0052] Figure 2 Schematic diagram showing the distribution of target state of charge differences over time in this application. Figure 2As shown in FIG, the horizontal axis represents the reference time difference between the preset time and the launch time, and the vertical axis represents the target state of charge difference. It can be seen that the density of the target state of charge difference varies at different preset times.

[0053] Furthermore, determining the target state of charge difference range of each battery cell according to the distribution of the plurality of target state of charge differences over time includes:

[0054] Step S31: obtaining the launch time of multiple vehicles, and calculating multiple reference time differences between the launch time and multiple preset times;

[0055] The vehicle's launch time may be pre-stored in the battery management system. The launch time may be accurate to the nearest day. Therefore, when calculating the reference time difference, since the preset time is in days, the reference time difference also takes days as the unit. The reference time difference may be an integer greater than 0.

[0056] Step S32: fitting the plurality of target state of charge differences and the plurality of reference time differences to obtain a first expression of the target state of charge differences and the reference time differences;

[0057] In one embodiment, the reference time difference is used as the horizontal axis and the target state of charge difference is used as the vertical axis, and the distribution of the plurality of target state of charge differences relative to the plurality of reference time differences is fitted to obtain a first expression of the target state of charge difference and the reference time difference. The first expression can be f1(Δt d ), f1 is the functional relationship between the target state of charge difference and the reference time difference, Δt d Optionally, the target state of charge difference and the reference time difference are in a linear relationship, and the functional relationship between the target state of charge difference and the reference time difference is a linear function.

[0058] Figure 3 A schematic diagram of the first expression of the present application is shown. Figure 3 As shown, the horizontal axis represents the reference time difference between the preset time and the launch time, and the vertical axis represents the target SOC difference. Because the target SOC difference varies in density at different preset times, a piecewise function with different slopes can be used to fit the relationship between the target SOC difference and the reference time difference.

[0059] Step S33: determining a first difference boundary and a second difference boundary based on the first expression to obtain a target state of charge difference range of each of the battery cells.

[0060] The first difference boundary and the second difference boundary are end values ​​of the target state of charge difference range, and the first difference boundary is smaller than the second difference boundary.

[0061] In one embodiment, the first difference boundary and the second difference boundary can be calculated using the first expression. For example, the initial first difference boundary and the second difference boundary can be set according to the requirements, and then the target state of charge difference of multiple unknown battery cells at a preset time can be calculated according to the first expression to check whether the target state of charge difference of the multiple unknown battery cells falls within the initial first difference boundary and the second difference boundary. If it does fall within, the initial first difference boundary and the second difference boundary remain unchanged. If it does not fall within, the initial first difference boundary and the second difference boundary can be changed with a set step size until the target state of charge difference of the multiple unknown battery cells with the target probability falls within the first difference boundary and the second difference boundary. At this time, the target state of charge difference range of each of the battery cells is obtained.

[0062] Step S4: Determine whether the current target state of charge difference of the current vehicle is within the target state of charge difference range. If the current target state of charge difference of the current vehicle is within the target state of charge difference range, mark the battery pack of the current vehicle as normal; if the current target state of charge difference of the current vehicle is outside the target state of charge difference range, issue an early warning of the battery pack abnormality of the current vehicle.

[0063] In one embodiment, determining whether the current target state of charge difference of the current vehicle is within the target state of charge difference range includes:

[0064] Step S41: obtaining initial state of charge differences of multiple vehicles at the time of launch;

[0065] Step S42: calculating a plurality of target SOC difference change rates at a plurality of reference time differences based on the initial SOC difference and a plurality of target SOC differences at different preset times;

[0066] In one embodiment, the target state of charge difference change rate can be calculated using the following formula:

[0067] ΔSOC'=(SOC0-SOC td ) / SOC0

[0068] Among them, SOC0 is the initial state of charge difference at the time of listing, SOC td is the target SOC difference at a preset time, and ΔSOC′ is the change rate of the target SOC difference.

[0069] Step S43: determining a target state of charge difference change rate range for each battery cell according to a distribution of a plurality of target state of charge difference change rates over time;

[0070] Furthermore, determining the target state of charge difference change rate range of each battery cell according to the distribution of the plurality of target state of charge difference change rates over time includes:

[0071] Step S431: fitting the plurality of target state of charge difference change rates and the plurality of reference time differences to obtain a second expression of the plurality of target state of charge difference change rates and the plurality of reference time differences;

[0072] In one embodiment, the reference time difference is used as the horizontal axis and the target state of charge difference change rate is used as the vertical axis. The distribution of multiple target state of charge difference change rates relative to multiple reference time differences can be fitted to obtain a second expression of the target state of charge difference change rate and the reference time difference. The second expression can be f2(Δt d ), f2 is the functional relationship between the target state of charge difference change rate and the reference time difference, Δt d Optionally, the target state of charge difference change rate and the reference time difference are in a linear relationship, and the functional relationship between the target state of charge difference change rate and the reference time difference is a linear function.

[0073] Step S432: determining a first change rate boundary and a second change rate boundary based on the second expression to obtain a target state of charge difference change rate range of each of the battery cells.

[0074] The first change rate boundary and the second change rate boundary are end values ​​of the target state of charge difference change rate range, and the first change rate boundary is smaller than the second change rate boundary.

[0075] In one embodiment, the first change rate boundary and the second change rate boundary can be calculated by the second expression in a similar manner to the first expression. For example, the initial first change rate boundary and the second change rate boundary can be set according to the requirements first, and then the target state of charge difference change rate of multiple unknown battery cells at the preset time can be calculated according to the first expression to check whether the target state of charge difference change rate of the multiple unknown battery cells falls within the initial first change rate boundary and the second change rate boundary. If it has fallen within, the initial first change rate boundary and the second change rate boundary remain unchanged. If it has not fallen within, the initial first change rate boundary and the second change rate boundary can be changed with a set step size until the target state of charge difference of the multiple unknown battery cells with the target probability falls within the first change rate boundary and the second change rate boundary. At this time, the target state of charge difference change rate range of each of the battery cells is obtained.

[0076] Furthermore, before determining whether the current target state of charge difference of the current vehicle is within the target state of charge difference range and whether the current target state of charge difference change rate is within the target state of charge difference change rate range, the battery pack abnormality early warning method includes:

[0077] Step S441: calculating a plurality of target state of charge differences and a plurality of standard deviations of target state of charge difference change rates;

[0078] Step S442: determining a target state of charge difference range of each battery cell and a target state of charge difference change rate range of each battery cell based on the standard deviation and a preset confidence interval.

[0079] In one embodiment, the target state of charge difference and target state of charge difference change rate for all vehicles at the same time of listing can be obtained with the time of listing as the starting point, and their mean and standard deviation are calculated. Then, the upper and lower limits of the target state of charge difference and the upper and lower limits of the target state of charge difference change rate are determined based on a specific confidence interval (such as 95%), thereby determining the target state of charge difference range for each battery cell and the target state of charge difference change rate range for each battery cell. It is worth noting that the target state of charge difference change rate range obtained in step S432 and the target state of charge difference change rate range obtained in step S442 can be replaced.

[0080] Step S44: determining whether the current target SOC difference of the current vehicle is within the target SOC difference range, and whether the current target SOC difference change rate is within the target SOC difference change rate range.

[0081] Further, the determining whether the current target state of charge difference of the current vehicle is within the target state of charge difference range, and whether the current target state of charge difference change rate is within the target state of charge difference change rate range, includes:

[0082] Step S441: If the current target state of charge difference of the current vehicle is within the target state of charge difference range, and the current target state of charge difference change rate is within the target state of charge difference change rate range, then the battery pack of the current vehicle is marked as normal; if the current target state of charge difference of the current vehicle is outside the target state of charge difference range or the current target state of charge difference change rate is outside the target state of charge difference change rate range, then an early warning is issued for the battery pack abnormality of the current vehicle.

[0083] In one embodiment, marking the vehicle's battery pack as normal can be achieved by sending a normal command to the battery management system, which will display a normal battery pack icon on the vehicle's central control screen. If the vehicle's battery pack is abnormal, an abnormal command can be sent to the battery management system, which will display an abnormal battery pack icon on the vehicle's central control screen and provide a voice prompt to the driver indicating that the battery pack is abnormal.

[0084] In addition, the present application also provides a battery pack abnormality warning device, which includes a processing unit connected to multiple vehicles, and the processing unit is used to implement the battery pack abnormality warning method.

[0085] Figure 4 FIG. 1 is a block diagram showing a processing unit according to an embodiment of the present application. Figure 4 As shown, the processing unit includes:

[0086] A data acquisition module 41 is configured to acquire multiple sets of open circuit voltage data of battery packs of multiple vehicles, wherein the open circuit voltage data includes the open circuit voltage of each cell in the battery pack;

[0087] a difference determination module 42 connected to the data acquisition module 41 and configured to obtain a plurality of target state of charge differences of all battery cells of a plurality of vehicles at different preset times based on the plurality of open circuit voltage data;

[0088] a range determination module 43, connected to the difference determination module 42, for determining a target state of charge difference range for each of the battery cells based on a distribution of the target state of charge differences over time;

[0089] The judgment module 44 is connected to the range determination module 43 and is used to judge whether the current target state of charge difference of the current vehicle is within the target state of charge difference range. If the current target state of charge difference of the current vehicle is within the target state of charge difference range, the battery pack of the current vehicle is marked as normal; if the current target state of charge difference of the current vehicle is outside the target state of charge difference range, an early warning is issued for the battery pack abnormality of the current vehicle.

[0090] For specific details about the processing unit, please refer to the relevant description of the battery pack abnormality warning method, which will not be repeated here.

[0091] In summary, by obtaining multiple copies of open circuit voltage data of battery packs of multiple vehicles, and obtaining multiple target state of charge differences of all battery cells of multiple vehicles at different preset times based on the multiple copies of open circuit voltage data, and then determining the target state of charge difference range of each battery cell according to the distribution of the multiple target state of charge differences over time, and finally judging whether the current target state of charge difference of the current vehicle is within the target state of charge difference range, the present application can realize the judgment of whether the state of charge at the level of single battery cells is abnormal, more effectively identify the abnormal risks of battery packs, and improve the safety of the whole vehicle. Moreover, by using a big data platform, the SOC difference changes of vehicle operation and static processes are recorded, compared, analyzed and summarized, and it can be identified whether it is a self-discharge abnormality in the vehicle or some batteries and vehicles in the battery pack that decay too quickly, and the abnormality of the battery pack can be discovered as early as possible. By using a big data platform, the parameter boundary of the model has a relatively sufficient amount of data to support it, and it has relatively strong representativeness.

[0092] 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.

[0093] The above is a detailed introduction to the battery pack abnormality warning method and battery pack abnormality warning device provided in the embodiments of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application; ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery pack abnormality warning method, characterized in that: include: Acquire multiple sets of open circuit voltage data of battery packs of multiple vehicles, the open circuit voltage data including the open circuit voltage of each cell in the battery pack; Obtaining a plurality of target state-of-charge differences for all battery cells of a plurality of vehicles at different preset times based on the plurality of open circuit voltage data; Determining a target state of charge difference range for each of the battery cells according to a distribution of the target state of charge differences over time; determining whether the current target state of charge difference of the current vehicle is within the target state of charge difference range, and if the current target state of charge difference of the current vehicle is within the target state of charge difference range, marking the battery pack of the current vehicle as normal; If the current target state of charge difference of the current vehicle is outside the target state of charge difference range, an early warning is issued for abnormality of the battery pack of the current vehicle; The method of determining the target state of charge difference range of each battery cell based on the distribution of multiple target state of charge differences over time includes: obtaining the launch time of multiple vehicles and calculating multiple reference time differences between the launch time and multiple preset times; fitting the multiple target state of charge differences and the multiple reference time differences to obtain a first expression for the target state of charge differences and the reference time differences; determining a first difference boundary and a second difference boundary based on the first expression to obtain the target state of charge difference range of each battery cell, wherein the first difference boundary and the second difference boundary are end values ​​of the target state of charge difference range, and the first difference boundary is smaller than the second difference boundary.

2. The battery pack abnormality warning method according to claim 1, characterized in that: The obtaining of a plurality of target state of charge differences of all battery cells of a plurality of vehicles at different preset times based on the plurality of open circuit voltage data includes: Obtaining multiple target states of charge for all battery cells of multiple vehicles based on the multiple copies of the open circuit voltage data; Traversing a plurality of open circuit voltages corresponding to a plurality of target states of charge to obtain a plurality of first open circuit voltage extreme values ​​and a plurality of second open circuit voltage extreme values ​​at different preset times; Obtaining, by reverse query, a plurality of first reference states of charge corresponding to a plurality of first open-circuit voltage extreme values ​​and a plurality of second reference states of charge corresponding to a plurality of second open-circuit voltage extreme values; A plurality of target state-of-charge differences for all battery cells of a plurality of vehicles at different preset times are determined according to a plurality of the first reference states of charge and a plurality of the second reference states of charge.

3. The battery pack abnormality warning method according to claim 2, characterized in that: The obtaining of multiple target states of charge of all battery cells of multiple vehicles based on multiple copies of the open circuit voltage data includes: Obtaining SOC-OCV curves of the battery cells of a plurality of vehicles; Obtaining a plurality of first states of charge of each of the battery cells when the vehicle is turned off according to the plurality of open circuit voltage data and the SOC-OCV curves of each of the battery cells; Correcting the plurality of first states of charge by ampere-hour integration to obtain a plurality of second states of charge of each of the battery cells; A plurality of target states of charge for all battery cells of a plurality of vehicles is determined based on a plurality of the first states of charge and a plurality of the second states of charge.

4. The battery pack abnormality warning method according to claim 2, characterized in that: The determining, based on the plurality of first reference states of charge and the plurality of second reference states of charge, a plurality of target state of charge differences of all battery cells of the plurality of vehicles at different preset times includes: Adding and averaging the first reference states of charge of all battery cells at the same preset time to obtain a first reference state of charge average value; Adding and averaging the plurality of second reference states of charge of all battery cells at the same preset time to obtain a second reference state of charge average value; A target state of charge difference for the preset time is obtained according to the first reference state of charge average value and the second reference state of charge average value.

5. The battery pack abnormality warning method according to claim 1, characterized in that: The battery pack abnormality warning method further includes: Obtain the initial state of charge differences of multiple vehicles at the time of launch; Calculating a plurality of target state-of-charge difference change rates for a plurality of reference time differences based on the initial state-of-charge difference and a plurality of target state-of-charge differences at different preset times; Determining a target state of charge difference change rate range for each of the battery cells according to a distribution of a plurality of target state of charge difference change rates over time; It is determined whether a current target state of charge difference of the current vehicle is within the target state of charge difference range, and whether a current target state of charge difference change rate is within the target state of charge difference change rate range.

6. The battery pack abnormality warning method according to claim 5, characterized in that: Determining the target state of charge difference change rate range of each battery cell according to the distribution of the plurality of target state of charge difference change rates over time includes: Fitting the plurality of target state of charge difference change rates and the plurality of reference time differences to obtain a second expression for the plurality of target state of charge difference change rates and the plurality of reference time differences; Based on the second expression, a first change rate boundary and a second change rate boundary are determined to obtain a target state of charge difference change rate range for each battery cell, wherein the first change rate boundary and the second change rate boundary are end values ​​of the target state of charge difference change rate range, and the first change rate boundary is smaller than the second change rate boundary.

7. The battery pack abnormality warning method according to claim 5, characterized in that: The determining whether the current target state of charge difference of the current vehicle is within the target state of charge difference range, and whether the current target state of charge difference change rate is within the target state of charge difference change rate range, includes: If the current target state of charge difference of the current vehicle is within the target state of charge difference range, and the current target state of charge difference change rate is within the target state of charge difference change rate range, the battery pack of the current vehicle is marked as normal; if the current target state of charge difference of the current vehicle is outside the target state of charge difference range, or the current target state of charge difference change rate is outside the target state of charge difference change rate range, an early warning is issued for the battery pack abnormality of the current vehicle.

8. The battery pack abnormality warning method according to claim 5, characterized in that: Before determining whether the current target state of charge difference of the current vehicle is within the target state of charge difference range and whether the current target state of charge difference change rate is within the target state of charge difference change rate range, the battery pack abnormality early warning method includes: calculating a plurality of target state-of-charge differences and a standard deviation of a plurality of target state-of-charge difference change rates; The target state of charge difference range of each of the battery cells and the target state of charge difference change rate range of each of the battery cells are determined based on the standard deviation and a preset confidence interval.

9. A battery pack abnormality warning device, characterized in that: The battery pack abnormality warning device includes a processing unit, which is connected to multiple vehicles and is used to implement the battery pack abnormality warning method according to any one of claims 1 to 8.

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