Battery safety monitoring method based on BIT and BMS data interaction

Abstract

The battery safety monitoring method based on the data interaction of BIT and BMS provided by the present invention, through the data interaction of BIT and BMS, each time the battery modules are mixed and merged, the historical number of times of mixing and merging and the feasibility of mixing and merging with the available balanced power group are considered to affect the power loss of the finally constructed mixed and merged battery group on the power consumption equipment. Therefore, each mixing and merging is based on the condition of maximizing the performance of the battery module. The condition of adding the battery module to the dependent unit set thus set can characterize the characteristics of the suspected failure of the battery module. Therefore, in this application, it is only necessary to determine in step L1 whether the number of times the battery module is added to the dependent unit set during the power supply interval between two full charges is greater than the preset number threshold, so as to quickly and more accurately identify whether the battery module is suspected of failure. In addition, by judging the similarity between the first deviation amplitude and the second deviation amplitude, it is possible to verify whether the suspected faulty battery is actually faulty.

Description

Technical Field

[0001] The present invention relates to the technical field of battery fault diagnosis, and in particular to a battery safety monitoring method based on BIT and BMS data interaction. Background Art

[0002] BIT (Built-in Test) technology, also known as internal comparison test technology, sends the collected values ​​of the hardware circuit to the BIT chip and compares them with the set algorithm, threshold or parameter to determine whether the device is normal. The principle of BIT built-in test technology is as follows: Figure 3 As shown. In the field of battery safety monitoring technology, the fault diagnosis module in the MCU chip in the BMS (BATTERY MANAGEMENT SYSTEM) system is usually used to diagnose whether the battery is faulty, but the complex diagnosis and error correction functions of this module are weak, and diagnostic errors are prone to occur. Therefore, this field usually integrates a BIT chip in the BMS system, and the BIT chip with strong fault diagnosis capabilities is used to perform battery fault diagnosis, alarm processing, and isolation of faulty batteries.

[0003] Normally, as the number of charge and discharge times of a battery module increases, the battery performance gradually decreases, and the probability of failure gradually increases. At present, the judgment of whether a battery module has a fault is usually performed when the cumulative number of charge and discharge times is reached. For example, the rated charge and discharge times of a battery module is 1,000 times. The manufacturer can set it to start monitoring the battery module to see if it shows the characteristics of a suspected fault when the cumulative number of charge and discharge times reaches 800 times. This kind of fault judgment has a lag. In some special power supply scenarios, it is more hoped that the fault judgment of the battery module can be pre-set to the power supply process of the power-consuming equipment during the interval between two full charges. For example, for the scenario where different types of batteries are mixed and then used to power the power-consuming equipment, during the mixing period, different types of mixed batteries will be mixed with the battery module, and the battery module will be charged. Each mixed charge is beneficial to the internal resistance repair of the battery module, which in turn helps to delay the performance degradation of the battery module and extend the service life of the battery module.

[0004] In this special power supply scenario, due to the different feasibility of mixing different types of batteries, for example, the mixing of battery module A and battery module B has a higher mixing feasibility than the mixing of battery module C with the same battery voltage as battery module B (for example, the internal resistance of battery module A is reduced more). Therefore, each time the mixing is performed, the degree of benefit of the mixed battery to the performance improvement of the battery module is basically different, and there is even the possibility of being more unfavorable to the performance improvement of the battery module, which will cause the cumulative number of charge and discharge times set by the manufacturer to start monitoring the suspected fault characteristics of the battery module to increase or decrease. Therefore, in this special power supply scenario, it is expected that the fault monitoring of the battery module can be pre-positioned to the power supply process of the electrical equipment during the interval between two full charges, so that no matter whether the cumulative number of charge and discharge times that meet the suspected fault characteristic monitoring conditions increases or decreases, it is possible to realize timely monitoring of whether the battery module has a suspected fault, and thus does not affect the mixed battery pack composed of various types of batteries to power the electrical equipment. However, for the above-mentioned special power supply scenarios, how to advance the fault judgment of the battery module to the period between every two full charges through data exchange between the BMS system and the BIT chip, and how to ensure the accuracy of judging whether the battery module has a fault after being mixed with different types of battery modules for multiple times are technical problems that need to be solved urgently in this application. Summary of the invention

[0005] The present invention aims to quickly and accurately identify whether a battery module fails in a scenario where different types of battery modules are mixed and supply power to electrical equipment, and provides a battery safety monitoring method based on BIT and BMS data interaction.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A battery safety monitoring method based on BIT and BMS data interaction is provided, the steps comprising:

[0008] L1, in the current charge and discharge cycle, the BMS chip determines whether the number of times the battery module joins the dependent unit set is greater than the preset number threshold.

[0009] If yes, the battery module is determined to be a suspected faulty battery and added to the suspected faulty battery set, and then a fault verification instruction is generated and sent to the BIT chip before proceeding to step L2;

[0010] If not, it is determined that the battery module has no suspected failure;

[0011] L2, the BIT chip performs a mixed simulation on the suspected faulty battery in the suspected faulty battery set according to the fault verification instruction to obtain parameter values ​​of a first parameter and a second parameter for calculating the feasibility of mixed merging;

[0012] L3, the BIT chip determines whether a first deviation of a first parameter value of the first parameter from a second parameter value of the second parameter is similar to a second deviation of a first weight corresponding to the first parameter from a second weight corresponding to the second parameter,

[0013] If yes, it is determined that the suspected faulty battery is not faulty, and a first execution instruction is generated and sent to the BMS chip;

[0014] If not, it is determined that the suspected faulty battery is faulty, and a second execution instruction is generated and sent to the BMS chip;

[0015] L4, the BMS chip removes the suspected faulty battery from the suspected faulty battery set according to the first execution instruction, or moves the suspected faulty battery into the faulty battery set according to the second execution instruction.

[0016] Preferably, in step L1, the condition for the battery module to join the dependent unit set is: in the current charge and discharge cycle, the battery module as a member of the difference battery group is used as a historical mixing object at least twice; and, as of now, the power supply loss of the historical mixed battery group containing the battery module to the same electrical equipment increases with the increase of the number of historical mixing times of the battery module.

[0017] Preferably, in each charge and discharge cycle, after each power supply to the electric device is completed, the method for the BMS battery management system to construct a hybrid battery pack for powering the electric device next time includes the steps of:

[0018] S1, according to the historical power supply data of the difference battery group to the electrical device in the current charge and discharge cycle, by calculating the minimum feasibility of mixing and merging, to find the object to be mixed and merged in the difference battery group;

[0019] S2, constructing an available balanced power group for each of the proposed mixed-in objects by calculating the mixed-in effectiveness of the proposed balanced power group for the proposed mixed-in objects and the mixed-in acceptance of the proposed mixed-in objects for the proposed balanced power group, and adding the available balanced power group to the set of available balanced power groups respectively associated with each of the proposed mixed-in objects;

[0020] S3, according to the power demand prediction result of the power-consuming device, identifying the available balanced power group that will supply power to the power-consuming device next time from each of the available balanced power group sets, and combining it with the associated proposed mixed-and-combined objects to form the mixed-and-combined battery group that will supply power to the power-consuming device next time;

[0021] After each power supply is completed, the BMS battery management system switches each battery module in the difference battery pack to a power-off isolation state.

[0022] Preferably, in step S1, the method for finding the quasi-mixed object comprises the steps of:

[0023] A1, obtaining a battery pack used to calculate the minimum hybrid feasibility;

[0024] A2, calculating the minimum hybrid feasibility according to the historical hybrid data of the battery pack;

[0025] A3, a simulation excitation source performs charging excitation on each remaining battery module in the difference battery pack except the dependent unit in the basis battery pack, so as to obtain the change rate of the available capacity of each battery module after the excitation;

[0026] A4, determines whether the difference between the available capacity change rate of each battery module and the second ratio used to calculate the minimum hybrid feasibility is greater than a preset difference threshold. If so, the battery module is added to the set of simulated hybrid objects as the simulated hybrid object for powering the electrical equipment next time.

[0027] Preferably, the method for obtaining the calculation basis battery group in step A1 is: sorting the battery modules in the dependent unit set from large to small according to the number of historical mixing and merging times to form a sorted list, and then obtaining the historical mixed and merged battery group of the battery module ranked first in the sorted list at the last historical mixing and merging time as the basis battery group for calculating the minimum mixing and merging feasibility;

[0028] In step A2, the minimum mixing feasibility is: a weighted sum of a first ratio of a first internal resistance change of the dependent unit to a second internal resistance change of the historical balanced power group from the start of mixing to the battery terminal voltage balance between the dependent unit in the battery pack and the historical balanced power group, and a second ratio of a change in the available battery capacity of the dependent unit to the charging time of the dependent unit from the start of mixing to the battery terminal voltage balance.

[0029] Preferably, in step S2, the method for constructing the available balanced power supply group for each of the quasi-mixed objects comprises the following steps:

[0030] B1, specifying the quasi-mixed object used to construct the proposed balanced power source group from the quasi-mixed object set;

[0031] B2, randomly extracting the same number of battery modules as the historical balanced power sources in the historical balanced power source group in the battery group used to calculate the minimum mixed feasibility from the specified remaining set of the proposed mixed objects as the proposed balanced power sources;

[0032] B3, connecting the extracted balanced power sources to be used in parallel to form a balanced power group to be used, and then mixing the balanced power group to be used with the object to be mixed and merged, and monitoring the mixed and merged data until each battery module in the balanced power group to be used reaches a battery terminal voltage balance state;

[0033] B4, calculating the feasibility of mixing and merging the planned balanced power source group and the planned mixed and merged object according to the mixed and merged data;

[0034] B5, judging whether the mixed-merge feasibility is greater than the minimum mixed-merge feasibility,

[0035] If yes, determining that the proposed balanced power group is the available balanced power group available to the proposed mixed and merged object, and adding it to the available balanced power group set associated with the proposed mixed and merged object;

[0036] If not, the process returns to step B2 to extract battery modules again to form different balanced power groups to be used, until it is no longer possible to form different balanced power groups to be used.

[0037] Preferably, in step S3, the method of identifying the available balanced power group for supplying power to the electrical device next time from the available balanced power group set associated with each of the objects to be mixed and merged comprises the following steps:

[0038] C1, filtering out the available balanced power groups whose power supply is less than the predicted power demand in the sets of available balanced power groups respectively associated with the proposed mixed-merging objects, and then arranging the remaining available balanced power groups from high to low according to the mixed-merging feasibility with the associated proposed mixed-merging objects to form a first list;

[0039] C2, calculating the difference between the battery performance of the pseudo-mixed objects associated with each of the available balanced power groups remaining after filtering in step C1 and the dependent units in the battery group, and arranging the pseudo-mixed objects from high to low according to the difference to form a second list;

[0040] C3: for a second element in the second list that has the same ranking as the first element in the first list, determine whether the number of element combinations that have an association relationship between the second element and the first element is at least "1"

[0041] If so, extract the element combination at the front of the sorting list, mix and merge them, and use them as the mixed and merged battery group for supplying power to the electrical device next time;

[0042] If not, the proposed hybrid object ranked first in the first list is hybridized with the available balanced power source group with the maximum hybrid feasibility to form the hybrid battery group for the next power supply.

[0043] Preferably, in step L2, the method for performing mixed simulation on the suspected faulty battery is:

[0044] From the previously mixed objects in the current charge and discharge cycle, the objects of the same type as the suspected faulty battery are screened out, and then the maximum mixed and balanced power supply group with the maximum mixing feasibility with each of the screened objects of the simulated mixed and combined is extracted, and then mixed and combined with the suspected faulty battery, the mixed and combined data are collected, including a first ratio of a first internal resistance change of the suspected faulty battery to a second internal resistance change of the maximum mixed and balanced power supply group from the start of mixing and combining to the time when the battery terminal voltage is balanced as the first parameter value, and a second ratio of a battery available capacity change of the suspected faulty battery to the mixing and combining time when the terminal voltage is balanced as the second parameter value;

[0045] In step L3, the first deviation amplitude is: a first absolute value of a difference between a first proportion of the first parameter value in a first sum of the first parameter value and the second parameter value and a second proportion of the second parameter value in the first sum.

[0046] Preferably, the method for solving the second deviation amplitude in step L3 comprises the steps of:

[0047] L31, assigning the first weight and the second weight corresponding to the first parameter and the second parameter respectively through curve fitting and slope solution;

[0048] L32, calculating a second absolute value of a difference between the first weight and the second weight as the second deviation amplitude;

[0049] When the absolute value of a third difference between the first deviation amplitude and the second deviation amplitude is smaller than a preset difference absolute value threshold, it is determined that the first deviation amplitude is similar to the second deviation amplitude.

[0050] Preferably, in step L31, the weighting method comprises the steps of:

[0051] L311, draw a first fitting curve and a second fitting curve of the first parameter and the second parameter respectively with respect to the historical mixing times, and align the data points on the first fitting curve and the second fitting curve, wherein the alignment method is: the first parameter value and the second parameter value used to calculate the same mixing feasibility have the same x-axis coordinate of the historical mixing times;

[0052] L312, filter out data points that are on the rising edge or falling edge of the first fitting curve and the second fitting curve and have an alignment relationship, and add them to the first point set and the second point set respectively;

[0053] L313, for each group of adjacent data points in the first point set and the second point set that are in the curve, respectively calculate a first slope and a second slope;

[0054] L314, calculates the first mean of each of the first slopes and the second mean of each of the second slopes, and calculates the second sum of the first mean and the second mean, and then calculates the fourth ratio of the first mean to the second sum as the second weight, and calculates the difference between "1" and the fourth ratio as the first weight.

[0055] The present invention has the following beneficial effects:

[0056] 1. Each time the battery modules are mixed, the impact of the historical number of times they are mixed and the feasibility of mixing with the available balanced power group on the power loss of the finally constructed mixed battery group on the power consumption of the electrical equipment is considered. Therefore, each mixing is based on the condition that the battery module performance is improved to the greatest extent. The conditions for the battery module to join the dependent unit set set in this way can characterize the characteristics of the suspected failure of the battery module. Therefore, in this application, it is only necessary to determine in step L1 whether the number of times the battery module is added to the dependent unit set during the interval between two full charges is greater than the preset number threshold, so as to quickly and more accurately identify whether the battery module is suspected of failure.

[0057] 2. By judging the similarity between the first deviation amplitude and the second deviation amplitude of step L2-L3, it is possible to further determine whether the battery module suspected of failure is actually faulty. The first deviation amplitude characterizes the current acceptance of the battery module for the available balanced power group with the maximum feasibility of mixing and merging with it, and the degree of deviation between the mixing effectiveness of the available balanced power group for mixing and merging the battery module. The greater the degree of deviation, the more obvious the characteristic of the suspected failure of the battery module. The second deviation amplitude takes into account the average balance characteristics between the acceptance of mixing and the effectiveness of mixing after each mixing of each battery module. When the first deviation amplitude and the second deviation amplitude have deviation similarities, it means that the characteristic intensity of the suspected failure of the battery module represented by the first deviation amplitude does not exceed the limit characteristics of the suspected faulty battery allowed for mixing and merging. Therefore, it is determined that the suspected faulty battery does not actually have a battery failure, and an accurate judgment is achieved on whether the suspected faulty battery module is actually faulty.

[0058] 3. In this embodiment, a dynamic mixing method considering power supply balance is provided for different types of differential batteries. Before each power supply to the electrical equipment, the number of times the battery module is used as the object of mixing is limited by searching for the object of mixing, so that the battery modules in the differential battery group after each full charge are first balanced in the number of times used; then, by calculating the mixing effectiveness of the intended balanced power group for the intended mixing object and the mixing acceptance of the intended mixed object for the intended balanced power group, the available balanced power group constructed for each intended mixed object is conducive to reducing the internal resistance and power supply loss of the intended mixed object, and improving the rationality of the screening of available balanced power groups; by predicting the power demand of the electrical equipment and taking the optimal mixing feasibility as the premise, through steps C1-C3, the optimal available balanced power group for the next power supply to the electrical equipment can be quickly identified among the multiple available balanced power groups that can be mixed by the same intended mixed object, thereby reducing the power supply loss.

[0059] 4. With constant current full charging of the difference battery pack as the restriction condition, through steps A11-A13, the historical mixed-merge object (dependent unit) with poor current power supply capacity and large power loss is found, and the basis battery group with the minimum mixed-merge feasibility with the historical mixed-merge object is found. In order to achieve balanced power supply of each battery module in the difference battery pack and reduce power loss, in the next power supply to the power-consuming equipment, on the condition of meeting the next power demand of the power-consuming equipment, in the set of quasi-mixed objects with higher power supply capacity than the dependent unit and lower power loss than the dependent unit, the battery module with a battery performance difference with the dependent unit higher than the difference threshold is preferentially selected as the quasi-mixed object, and an available balanced power group set is constructed for each quasi-mixed object through steps B1-B5, and then an available balanced power group that can meet the next power demand of the power-consuming equipment is matched through steps C1-C5, so as to achieve balanced power supply of each battery module in the difference battery pack to the power-consuming equipment.

[0060] 5. The minimum feasibility of mixing and merging is calculated based on the effectiveness of the historical balanced power group in reducing the internal resistance of the dependent unit (characterized by the first ratio) and the acceptance of the dependent unit to the historical balanced power group to reduce its internal resistance (characterized by the second ratio) when the historical balanced power group in the battery group is mixed and merged with the dependent unit in the battery group until the battery terminal voltage is balanced. This expresses the minimum requirement for mixing and merging the difference batteries under the condition of meeting the historical power demand of the power-consuming equipment. That is, in the next mixed and merged battery group that supplies power to the power-consuming equipment, the effectiveness of the formed available balanced power group in reducing the internal resistance of the selected object to be mixed and merged is higher than the first ratio, and the acceptance of the object to be mixed and merged to reduce its internal resistance by the available balanced power group is higher than the second ratio. In this way, in each power supply to the power-consuming equipment, by reducing the selection of battery modules with poor power supply capacity and large power supply loss, each difference battery can achieve balanced power supply to the same power-consuming equipment, thereby extending the service life of each battery module.

[0061] 6. In the process of searching for the quasi-mixing object, the dependent unit in the battery pack used to calculate the minimum feasibility of mixing is used as a reference, and the battery module with similar or higher battery performance than the dependent unit is searched in the difference battery pack as the quasi-mixing object. The search is realized by charging incentives for each battery module. The incentive source separately charges each battery module with different charging currents and the same charging time of the dependent unit according to each historical balanced power source in the battery pack, and expresses the degree of acceptance of the battery module for charging incentives using the same charging conditions of the dependent unit through the rate of change of available capacity, so as to evaluate the similarity of the battery module's current battery performance with that of the dependent unit. Then, the battery module with similar or higher battery performance than the dependent unit is used as the quasi-mixing object, so as to avoid the problem that the battery modules in the difference battery pack become more and more unbalanced in the power supply of the next power supply to the electrical equipment due to the use of battery modules with worse performance than the dependent unit, and the power supply loss becomes larger and larger.

[0062] 7. Through steps B1-B5, the effectiveness of the proposed balanced power supply group for the proposed mixed object and the acceptance of the proposed mixed object to the proposed balanced power supply group are calculated, so as to realize the rapid and accurate search for the available balanced power supply group for the proposed mixed object, which is beneficial to improve the balance of the power supply to the electrical equipment by the mixed battery group found in the subsequent steps C1-C3.

[0063] 8. Through steps C1-C3, a rapid and accurate search is achieved for the hybrid battery pack that will power the electrical equipment next time.

[0064] 9. When the number of times the same battery module is added to the dependent unit set is greater than the preset number threshold, the battery module can be determined to be a suspected faulty battery. Before each power supply to the electrical equipment, the dependent unit is found as the basis for judging whether the battery is suspected of having a fault in the process of searching for the quasi-mixed objects in steps A1-A4, so that the process of finding a suspected faulty battery is simplified to counting the number of times the same battery module is added to the dependent unit set, and finding a suspected faulty battery is simpler, more efficient, and more intelligent. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0066] Figure 1 1 is a diagram of implementation steps of a battery safety monitoring method based on BIT and BMS data interaction provided by an embodiment of the present invention;

[0067] Figure 2 is an example diagram of a first fitting curve and a second fitting curve of the first parameter and the second parameter respectively with respect to the number of historical mixing times;

[0068] Figure 3 It is the principle block diagram of BIT built-in test technology. DETAILED DESCRIPTION

[0069] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0070] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on this patent; in order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0071] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as a limitation on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0072] In the description of the present invention, unless otherwise clearly specified and limited, if the term "connection" or the like appears to indicate the connection relationship between components, the term should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two components or the interaction relationship between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] The battery safety monitoring method based on BIT and BMS data interaction provided by the embodiment of the present invention is as follows: Figure 1 As shown, the steps include:

[0074] L1, in the current charge and discharge cycle, the BMS chip determines whether the number of times the battery module joins the dependent unit set is greater than the preset number threshold.

[0075] If yes, the battery module is determined to be a suspected faulty battery and added to the suspected faulty battery set. Then, a fault verification instruction is generated and sent to the BIT chip, and then the process goes to step L2.

[0076] If not, it is determined that the battery module is suspected of failure;

[0077] L2, the BIT chip performs mixed simulation on the suspected faulty batteries in the suspected faulty battery set according to the fault verification instruction, and obtains parameter values ​​of the first parameter and the second parameter for calculating the feasibility of mixed simulation;

[0078] L3, the BIT chip determines whether a first deviation of a first parameter value of a first parameter from a second parameter value of a second parameter is similar to a second deviation of a first weight corresponding to the first parameter from a second weight corresponding to the second parameter.

[0079] If yes, it is determined that the suspected faulty battery is actually faulty, and a first execution instruction is generated and sent to the BMS chip;

[0080] If not, it is determined that the suspected faulty battery is faulty, and a second execution instruction is generated and sent to the BMS chip;

[0081] The BMS chip removes the suspected faulty battery from the suspected faulty battery set according to the first execution instruction, or moves the suspected faulty battery into the faulty battery set according to the second execution instruction.

[0082] The following describes how to implement each of the above steps L1-L3:

[0083] In this embodiment, one charge-discharge cycle is: during the interval between two consecutive constant current full charge operations on the difference battery pack, the charge-discharge process of the difference battery pack is one charge-discharge cycle. At this moment, the BMS (BATTERYMANAGEMENT SYSTEM) controls the external power supply to perform a constant current full charge operation on each battery module in the differential battery pack. After full charge, based on the prediction results of each power demand of the power-consuming equipment, the BMS takes balanced power supply as the goal, and selects the battery modules that will power the power-consuming equipment next time from the differential battery pack to form a mixed battery pack. In this way, through repeated predictions of the power supply demand of power-consuming equipment and repeated construction of mixed battery packs, the BMS's power supply calls for each battery module in the differential battery pack will become more and more balanced. When the differential battery pack meets the conditions for constant current full charge again, the BMS controls the external power supply to The constant current full charging operation is performed again on the different battery packs at any time. Constant current full charging starts from the moment the full charging is completed until The constant current full charging operation is performed again at this moment, and this period is one charge and discharge cycle.

[0084] There are two types of discharge in a charge-discharge cycle: 1. The discharge of the hybrid battery pack to power the electrical equipment; 2. The discharge of the balanced power group in the hybrid battery pack as the hybrid object. In the following content, the definitions of the hybrid object and the balanced power group will be explained.

[0085] There are also two types of charging in a charge-discharge cycle: 1. When the mixed object is mixed with the balanced power group, the balanced power group charges the mixed object; 2. The simulated excitation source is the simulated charging of the mixed object.

[0086] In step L1, the conditions for adding the battery module to the dependent unit set are:

[0087] In the current charge and discharge cycle, the battery module as a member of the difference battery group has been used as a historical mixing object at least twice, and as of now, the power supply loss of the historical mixing battery group containing this battery module to the same power-consuming device increases with the increase in the number of historical mixing of the battery module. The reason why the conditions for the battery module to join the dependent unit set are set in this way will be emphasized in the subsequent content.

[0088] In each charge and discharge cycle, after each power supply to the electrical device is completed, the BMS battery management system constructs a method for a hybrid battery pack to power the electrical device next time, including the following steps:

[0089] S1, according to the historical power supply data of the difference battery group to the power-consuming device in the current charge and discharge cycle, by calculating the minimum feasibility of mixing and merging, to find the quasi-mixing object in the difference battery group, the searching method specifically includes the following steps:

[0090] A1, obtaining a battery pack for calculating the minimum hybrid feasibility, wherein the obtaining method specifically comprises the following steps:

[0091] A11, select each battery module that has been used as a historical mixing object at least twice from the difference battery group, and then construct a power loss list corresponding to each selected battery module, and the construction method is:

[0092] According to the historical mixing and merging sequence, the power loss of the historical mixed and merged battery group containing the battery module in supplying power to the electrical equipment is sorted to obtain a power loss list corresponding to each battery module;

[0093] For example, during one charge and discharge cycle, at the current time point when predicting the next power demand of the power-consuming device, the battery modules 005, 001, and 002 in the difference battery group have been used as historical mixed objects 3 times, 2 times, and 2 times respectively. Then, the battery modules 005, 001, and 002 are screened out from the difference battery group, and then the power loss lists corresponding to the battery modules 005, 001, and 002 are constructed. The construction method is as follows:

[0094] Suppose that the historical mixed-and-combined battery groups containing battery module 005 are (battery module 001, battery module 003, battery module 005), (battery module 001, battery module 002, battery module 005), and (battery module 002, battery module 004, battery module 005), among which the historical mixed-and-combined battery group (battery module 001, battery module 003, battery module 005) is mixed the earliest during this charge and discharge cycle, followed by (battery module 001, battery module 002, battery module 005), and finally (battery module 002, battery module 004, battery module 005). Suppose also that the power supply losses of the historical mixed-and-combined battery groups (battery module 001, battery module 003, battery module 005), (battery module 001, battery module 002, battery module 005), and (battery module 002, battery module 004, battery module 005) to the same electrical equipment are respectively , , , then according to the above sorting rules, the power loss list corresponding to the battery module 005 is expressed in the following Table 1:

[0095] Table 1

[0096]

[0097] The power loss list corresponding to battery module 001 is expressed in Table 2 below:

[0098] Table 2

[0099]

[0100] The power loss list corresponding to the battery module 002 is expressed in the following Table 3:

[0101] Table 3

[0102]

[0103] A12, for each battery module, determine whether each power loss in the associated power loss list increases with the increase of its historical mixing times.

[0104] If yes, then add the battery module to the dependent unit set for minimum hybrid feasibility calculation, and then go to step A13;

[0105] If not, the battery module is determined to be a non-dependent unit with minimum hybrid feasibility;

[0106] Assumptions , then according to the judgment rule of step A12, each power loss in the power loss list associated with battery module 005 does not increase with the increase of its historical mixing times, indicating that when the historical mixing battery group containing battery module 005 is used to power the power-consuming device for multiple times, the mixing feasibility of battery module 005 and each historical balanced power group does not decrease successively with the increase of the historical mixing times, indicating that in each historical mixing, there is at least one experience of successfully saving the battery module 005 whose power supply capacity decreases with the increase of the mixing times by constructing the historical available balanced power group of battery module 005, indicating that the power supply value of battery module 005 to the power-consuming device is not the lowest among the battery modules in the difference battery group. Therefore, battery module 005 is not added to the dependent unit set.

[0107] It should be noted here that the construction of the dependent unit set has two purposes: first, to find the basis battery group for calculating the minimum hybrid feasibility; second, to judge whether the battery module is a suspected faulty battery based on the number of times the same battery module is added to the dependent unit set, so as to realize the rapid identification of the suspected faulty battery.

[0108] Similarly, according to the judgment rule of step A12, each power loss in the power loss list associated with battery module 001 does not increase with the increase of its historical mixing times, so battery module 001 is also not added to the dependent unit set. However, each power loss in the power loss list associated with battery module 002 increases with the increase of its historical mixing times, so battery module 002 is added to the dependent unit set.

[0109] A13, sort the battery modules in the dependent unit set according to the number of historical mixing and merging times from large to small to form a sorted list, and then obtain the historical mixed and merged battery group of the battery module ranked first in the sorted list at the last historical mixing and merging time, as the basis battery group for calculating the minimum mixing and merging feasibility.

[0110] For example, assuming that after step A12, the battery modules in the dependent unit set include battery modules 002 and 008, wherein the historical mixing times of battery module 002 is "2", and the historical mixing times of battery module 008 is "2", then the formed sorting list is shown in Table 4 below:

[0111] Table 4

[0112]

[0113] According to the extraction rule of the historical mixed battery group in step A13, extract the historical mixed battery group of battery module 002 or 008 at the last time in history. Assuming that the historical mixed battery group of battery module 002 at the last time in history is (battery module 002, battery module 004, battery module 005), then extract the historical mixed battery group (battery module 002, battery module 004, battery module 005) as the basis battery group for calculating the minimum mixed feasibility.

[0114] It should also be noted that the power loss of the hybrid battery pack is calculated using the following formula (1):

[0115]

[0116] In formula (1), The power supply loss of the historical hybrid battery pack to power the electrical equipment;

[0117] The first in the history of mixed battery packs The change in available capacity of each battery module during power supply;

[0118] Indicates the number of battery modules in the historical mixed battery pack;

[0119] Indicates the amount of electricity consumed by an electrical device during the power supply period.

[0120] After going through steps A11-A13, after obtaining the reference battery group for calculating the minimum hybrid feasibility, the method of finding the quasi-hybrid object in the difference battery group proceeds to step:

[0121] A2, calculate the minimum hybrid feasibility based on the historical hybrid data of the battery pack;

[0122] The historical mixing data based on the battery group used to calculate the minimum mixing feasibility includes: the first internal resistance change of the dependent unit and the battery available capacity change from the start of mixing to the battery terminal voltage balance between the dependent unit in the battery group and the historical balanced power group in the battery group, the second internal resistance change of the historical balanced power group, the charging time of the dependent unit from the start of mixing to the battery terminal voltage balance, and the discharge current of each historical balanced power supply in the historical balanced power group.

[0123] The following is an example of the historical mixed data of the battery pack:

[0124] For example, the battery module 002 is determined to be a dependent unit after steps A11-A12, and the historical mixed battery group (battery module 002, battery module 004, battery module 005) is the basis battery group for calculating the minimum mixed feasibility, and battery modules 004 and 005 constitute a historical balanced power group mixed with battery module 002 as a dependent unit. After battery modules 004 and 005 are historically mixed with battery module 002 as a dependent unit, the historical balanced power group begins to discharge battery module 002, and battery module 002 is charged from the historical balanced power group. When the three battery modules reach a balance in battery terminal voltage, the charging time is assumed to be When battery modules 004 and 005 are discharged at a constant voltage, the discharge currents are assumed to be , At the beginning of hybridization, the internal resistance of battery module 002 is assumed to be , when the battery terminal voltage is balanced, assuming the internal resistance is , the first internal resistance change is At the beginning of the hybrid, the internal resistance of the historical balanced power group composed of battery modules 004 and 005 is assumed to be When the battery terminal voltage is balanced, the internal resistance of the historical balanced power group is assumed to be , then the second internal resistance change is The change in available battery capacity of battery module 002 is assumed to be (the difference between the available battery capacity when the battery terminal voltage is balanced and the available battery capacity when the mixing starts), then the historical mixing data of the battery pack includes , , , , , .

[0125] In step A2, the calculation of the minimum feasibility of mixing and merging is determined by two factors: first, the effectiveness of the historical balanced power group in the battery pack in reducing the internal resistance of the dependent unit; second, the acceptance of the dependent unit to the historical balanced power group for reducing its internal resistance. Since the types and performances of the battery modules in the difference battery pack are different, the dependent unit has different acceptance of mixing and merging of the historical balanced power groups composed of battery modules of different types and performances. This acceptance, in this embodiment, is defined as the acceptance of the dependent unit to reduce its internal resistance by the historical balanced power group.

[0126] The first of the two factors that determine the minimum hybrid feasibility is characterized by the ratio of the first internal resistance change to the second internal resistance change (defined as the first ratio) in this embodiment; the second factor is characterized by the ratio of the battery available capacity change of the dependent unit to the charging time (defined as the second ratio). The minimum hybrid feasibility is expressed as the weighted sum of the first ratio and the second ratio. For example, in the above example, and The ratio (first ratio) and and The weighted sum of the ratios (defined as the second ratio) of the first and second ratios. It should be noted here that when calculating the weighted sum, the weights assigned to the first ratio and the second ratio can be solved by the relevant functions and algorithms based on the historical mixed data of each historical mixed battery group. The weights assigned to the first ratio and the second ratio are directly related to the accurate judgment of whether the suspected faulty battery is actually faulty in this embodiment, which will be emphasized in the following content.

[0127] After step A2, after calculating the minimum hybrid feasibility, the method of finding the quasi-hybrid objects in the different battery groups proceeds to step:

[0128] A3, simulate the excitation source according to the historical hybrid data used to calculate the minimum hybrid feasibility, and then use the simulated excitation source to charge and stimulate each battery module in the difference battery pack except the dependent unit in the battery pack separately to obtain the change rate of the available capacity of each battery module after the stimulation.

[0129] It should be noted here that the excitation source includes several charging links corresponding to a historical balanced power source in the battery pack, and one charging link has a charging current for mixed charging of dependent units with the corresponding historical balanced power source; each charging link excites each battery module with the same charging time of the dependent unit based on the historical balanced power source group in the battery pack; after the charging excitation, the rate of change of the available capacity of the battery module is: the third ratio of the change in the available capacity of the battery module to the charging time.

[0130] For example, in the above-mentioned example, the historical balanced power supply group includes historical balanced power supplies 004 and 005, and the historical balanced power supplies 004 and 005 are the charging currents of the battery module 002 as the dependent unit for historical mixed charging, respectively. , , then the discharge currents output by the two charging links simulated by the excitation source are , The charging time for each battery module in the difference battery pack except the battery module 002 as the dependent unit is The calculation method of the change rate of the available battery capacity of each battery module after charging stimulation has been explained in the above example and will not be repeated here.

[0131] After step A3, the available capacity change rate of each battery module is obtained through charging stimulation, and the method of finding the quasi-mixing object in the difference battery group is transferred to step:

[0132] A4, determining the ratio of the available capacity change rate of each battery module to the second ratio used to calculate the minimum hybrid feasibility ( and is greater than a preset difference threshold; if so, the battery module is added to the set of quasi-mixed objects as a quasi-mixed object for supplying power to the electrical device next time.

[0133] It should be noted here that if the difference is greater than the difference threshold, it means that the power supply performance of the battery module is suspected to be better than that of the dependent unit. The greater the difference is greater than the difference threshold, the more excellent the performance of the battery module is compared with the dependent unit. Using these batteries as the simulated mixed-in objects for the next power supply can avoid using battery modules that have been mixed-in too many times as mixed-in objects again, and reduce the reuse of these battery modules that usually have large power supply losses and obvious performance degradation, so as to achieve balanced power supply to each battery module in the difference battery pack.

[0134] After finding the proposed mixed-and-merged object in the difference battery group through the above step S1, the method for constructing the mixed-and-merged battery group for supplying power to the electric device next time provided by this embodiment proceeds to the step:

[0135] S2, by calculating the effectiveness of the proposed balanced power group on the proposed mixed object, and calculating the acceptance of the proposed mixed object to the proposed balanced power group, construct an available balanced power group for each proposed mixed object, and add it to the available balanced power group set associated with each proposed mixed object.

[0136] Specifically, the method for constructing an available balanced power supply group for each quasi-mixed object includes the following steps:

[0137] B1. Specify the simulated mixed objects used to construct the simulated balanced power group from the simulated mixed object set. For example, assuming that the simulated mixed object set includes battery modules 009, 010, 011, and 012, when it is necessary to construct the simulated balanced power group for battery module 009, first specify battery module 009 from the simulated mixed object set.

[0138] B2, randomly extract the same number of battery modules as the historical balanced power sources in the historical balanced power source group in the basis battery group used to calculate the minimum mixed feasibility from the specified remaining set of objects to be mixed and merged as the balanced power sources to be used. For example, the historical balanced power source group in the basis battery group in the above example includes battery modules 004 and 005, and the number of historical balanced power sources in the basis battery group is "2", then randomly extract 2 battery modules from the example set of objects to be mixed and merged as the balanced power sources to be used for the object to be mixed and merged 009, such as extracting battery modules 010 and 011, or 010 and 012, or 011 and 012 as the balanced power sources to be used for the battery module 009.

[0139] B3, connect the extracted balanced power sources to be used in parallel to form a balanced power group to be used, for example, connect the extracted battery modules 010 and 011 in parallel to form a balanced power group to be used. Then, after the balanced power group to be used is mixed and merged with the object to be mixed and merged, the mixed and merged data is monitored until the battery modules in the balanced power group to be used reach a balanced state of battery terminal voltage.

[0140] What data the mixed data includes has been explained in the above example of the historical mixed data of the battery pack, and will not be repeated here.

[0141] B4, the feasibility of mixing and merging the proposed balanced power source group and the proposed mixed and merging object is calculated according to the mixed and merging data. The calculation method of the mixed and merging feasibility is the same as the calculation method of the minimum mixed and merging feasibility in the above example, which will not be repeated.

[0142] B5, determine whether the mixed feasibility is greater than the minimum mixed feasibility,

[0143] If so, the proposed balanced power supply group is determined to be an available balanced power supply group available to the proposed mixed-merging object, and is added to the set of available balanced power supply groups associated with the proposed mixed-merging object;

[0144] If not, return to step B2 and re-extract battery modules to form a different intended balanced power group, for example, extract battery modules 010 and 012 to form a proposed balanced power group different from the intended balanced power group composed of 010 and 011, until it is no longer possible to continue to form different intended balanced power groups.

[0145] Through the above steps B1-B5, a set of available balanced power groups associated with each simulated mixed object is formed. However, the set of available balanced power groups includes at least one available balanced power group. In order to further improve the balance of power supply of different battery groups, it is also very important to select the best available balanced power group from the set of available balanced power groups and combine it with the corresponding simulated mixed object to form a mixed battery group to power the electrical equipment next time. But how to select the best available balanced power group? In order to solve this technical problem, in this embodiment, by predicting the next power demand of the electrical equipment, and taking the next power demand of the electrical equipment to be met after mixing as a condition, and taking the simulated mixed object having the highest acceptance of the available balanced power group to prompt it to reduce its internal resistance, and the available balanced power group having the greatest effectiveness in reducing the internal resistance of the simulated mixed object as a premise, the technical problem is solved through step S3. Specifically:

[0146] After step S2, after finding the available balanced power supply group set associated with each proposed hybrid object, the method of constructing the hybrid battery group for powering the electrical device next time turns to step:

[0147] S3, based on the prediction result of the power demand of the power-consuming device for the next time, identify the available balanced power group that will supply power to the power-consuming device next time from the set of available balanced power groups associated with each proposed mixed-and-merged object, and then mix and merge the proposed mixed-and-merged objects associated with the available balanced power group to form a mixed-and-merged battery group that will supply power to the power-consuming device next time.

[0148] It should be noted that there are many existing methods for predicting the next power demand of electrical equipment, such as predicting by curve fitting based on historical power consumption data. Since the power consumption prediction method for electrical equipment is not within the scope of the present invention, it will not be explained.

[0149] In this embodiment, the method for identifying an available balanced power group for supplying power to an electric device next time from the available balanced power group set associated with each to-be-mixed object includes the following steps:

[0150] C1, filtering out the available balanced power groups whose power supply is less than the predicted power demand in the set of available balanced power groups associated with each proposed mixed-merging object, and then arranging the remaining available balanced power groups from high to low according to the mixed-merging feasibility with the associated proposed mixed-merging object to form a first list;

[0151] For example, assume that the available balanced power supply groups associated with the proposed mixed objects such as battery modules 009, 010, 011, and 012 are expressed as X, Y, Z, and W, respectively, where set X includes 2 available balanced power supply groups, x1 and x2; set Y includes 1 available balanced power supply group, y1; set Z includes 3 available balanced power supply groups, z1, z2, and z3; and set W includes 2 available balanced power supply groups, w1 and w2. Assuming that the predicted power demand is Q, and the power supply of x2, z2, z3, and w2 is less than Q, x2, z2, z3, and w2 are filtered out, and the remaining x1, y1, z1, and w1 are arranged from high to low according to the mixed feasibility with the respectively associated proposed mixed objects 009, 010, 011, and 012, to form the first list. Assuming that the feasibility of the combination of 009 and x1 is greater than the feasibility of the combination of 010 and y1, the feasibility of the combination of 011 and z1, and the feasibility of the combination of 012 and w1, the first table is expressed as shown in Table 5 below:

[0152] Table 5

[0153]

[0154] C2, calculating the difference between the pseudo-mixed objects associated with each available balanced power group remaining after filtering in step C1 and the battery performance of the dependent unit in the battery group, and arranging each pseudo-mixed object from high to low according to the difference to form a second list;

[0155] For example, the battery performance difference between the battery module 009 in Table 5 and the battery module 002 as the dependent unit is greater than the battery performance difference between the battery module 011 and the battery module 002, greater than the difference between the battery module 010 and the battery module 002, and greater than the difference between the battery module 012 and the battery module 002. Then, according to the rule of step C2, the second table is expressed as shown in Table 6 below:

[0156] Table 6

[0157]

[0158] It should be noted here that the battery performance difference described in step C2 is the absolute value of the difference between the third ratio of the above-mentioned simulated mixed object and the second ratio of the above-mentioned dependent unit. The larger the absolute value of the difference, the greater the difference between the two, otherwise the smaller it is.

[0159] C3, for the second element in the second list that has the same ranking as the first element in the first list, determine whether the number of element combinations that have an association relationship between the second element and the first element is at least "1",

[0160] If yes, extract the top-ranked element combination and mix and merge them as the mixed and merged battery group to power the electrical device next time;

[0161] If not, the proposed hybrid object ranked first in the first list is hybridized with the available balanced power source group with the maximum hybrid feasibility to form a hybrid battery group for the next power supply.

[0162] For example, the second element "009" in the second list expressed in Table 6 has the same ranking as the first element "x1" in the first list, and both are ranked first in the list, and the second element "012" has the same ranking as the first element "w1" in the first list, and both are ranked last in the list. In addition, the battery module 009 and the available balanced power group x1, as well as the battery module 012 and the available balanced power group w1 have been subjected to mixed feasibility calculations, indicating that there is an association relationship between 009 and x1, and there is an association relationship between 012 and w1. Then step C3 determines that the number of element combinations that have an association relationship with the first element is "2", and the element combination with the first ranking is extracted, that is, the battery module 009 and the available balanced power group x1 are used as the mixed battery group to power the electrical equipment next time.

[0163] Assuming that the number of element combinations is "0", the first-ranked simulated mixed object, that is, battery module 009, is extracted from the first list, and mixed with the available balanced power supply group (assuming it is x2) with the maximum mixing feasibility to form a mixed battery group that will power the electrical device next time.

[0164] After the above steps S1-S3, this embodiment can also quickly identify suspected faulty batteries by determining whether the number of times the same battery module is added to the dependent unit set is greater than a preset number threshold. If so, the battery module is determined to be a suspected faulty battery.

[0165] After going through the above step L1, after identifying the suspected faulty battery, if Figure 1 As shown, the battery safety monitoring method based on BIT and BMS data interaction provided in this embodiment enters the steps:

[0166] L2, performing a mixed simulation on the suspected faulty batteries in the suspected faulty battery set to obtain parameter values ​​of a first parameter and a second parameter for calculating the feasibility of the mixed simulation;

[0167] The purpose of step L2 is to obtain verification parameters for verifying whether the suspected faulty battery is a real faulty battery, that is, parameter values ​​of the first parameter and the second parameter.

[0168] In step L2, the method for performing mixed simulation on the suspected faulty battery is:

[0169] From all the simulated mixed objects that have been mixed in the current charge and discharge cycle, screen out the simulated mixed objects of the same type as the suspected faulty battery, then extract the maximum mixed and balanced power supply group with the maximum mixing feasibility with each screened simulated mixed object, and then collect the mixed data after mixing with the suspected faulty battery.

[0170] For example, suppose that in the current charge and discharge cycle, three mixing and merging have been experienced. The simulated mixing and merging objects of each of the three historical mixing and merging are a1, a2, a3, and a4 respectively. Suppose that a4 is determined to be a suspected faulty battery, and the battery types of a1 and a2 are the same as a3, and the simulated mixing and merging objects that have been screened out and have the same type as the suspected faulty battery a3 are a1 and a2. Suppose that the historical mixed and balanced power supply groups mixed with a1 and a2 are P1 and P2 respectively, and suppose that the mixing and merging feasibility of a1 and P1 is greater than the mixing and merging feasibility of a2 and P2, then the maximum mixed and balanced power supply group extracted is P1, and then P1 is mixed with a4, and the mixed and merging data is collected.

[0171] The mixing data includes: the ratio of the first internal resistance change of the suspected faulty battery to the second internal resistance change of the maximum mixed and balanced power supply group from the start of mixing to the battery terminal voltage balance of each mixed battery module (defined as the first ratio) as the first parameter value, and the ratio of the battery available capacity change of the suspected faulty battery to the mixing time when the terminal voltage balance is reached (defined as the second ratio) as the second parameter value.

[0172] After obtaining the first parameter value and the second parameter value of the suspected faulty battery through the mixed simulation of step L2, the battery safety monitoring method based on BIT and BMS data interaction provided in this embodiment is as follows: Figure 1 As shown, proceed to step:

[0173] L3, determining whether a first deviation of a first parameter value of a first parameter from a second parameter value of a second parameter is similar to a second deviation of a first weight corresponding to the first parameter from a second weight corresponding to the second parameter,

[0174] If so, it is determined that the suspected faulty battery has not failed;

[0175] If not, the suspected faulty battery is determined to be faulty and is moved to the faulty battery set.

[0176] The first deviation amplitude is: the absolute value of the difference between the first proportion of the first parameter value in the first sum of the first parameter value and the second parameter value and the second proportion of the second parameter value in the first sum (defined as the first difference absolute value). For example, assuming that the first parameter value is 1.5 and the second parameter value is 2.2, the first sum is 3.7, the first proportion is 0.405, the second proportion is 0.595, and the first difference absolute value is 0.19.

[0177] The method for solving the second deviation amplitude includes the steps of:

[0178] L31, assigning a first weight and a second weight corresponding to the first parameter and the second parameter respectively through curve fitting and slope solution, and the weight assignment method specifically includes the steps of:

[0179] L311, draw the first fitting curve and the second fitting curve of the first parameter and the second parameter respectively with respect to the number of historical mixing times (the first fitting curve and the second fitting curve are respectively as shown in Figure 2 ); the drawing method is: for each pseudo-mixed object that has been mixed in the past, the first parameter value and the second parameter value associated with it are the coordinate values ​​of the y-axis on the first fitting curve and the second fitting curve respectively, and the number of times the pseudo-mixed object has been mixed in the past is the coordinate value of the x-axis on the first fitting curve and the second fitting curve, and the data points (first parameter value, historical number of mixing) and the data points (second parameter value, historical number of mixing) for solving the feasibility of mixing of each pseudo-mixed object that has undergone mixing are respectively drawn into the xy-axis coordinate system, and then each data point is fitted to the corresponding first fitting curve and second fitting curve through a fitting function, such as a quadratic equation.

[0180] Then, the data points on the first fitting curve and the second fitting curve are aligned, and the alignment method is: the first parameter value and the second parameter value used to calculate the same blending feasibility have the same x-axis coordinate of the historical blending times. Figure 2 In , data points p1 and p11 are used to calculate the same mixed feasibility, so their x-axis coordinates are the same, so data points p1 and p11 are aligned data points. Similarly, data points p2 and p22 are aligned data points; data points p3 and p33 are aligned data points.

[0181] L312, filter out data points that are on the rising edge or falling edge of the first fitting curve and the second fitting curve and have an alignment relationship, and add them to the first point set and the second point set respectively;

[0182] For example, Figure 2 The data points p1, p2, and p3 are on the falling edge, p11 and p22 are on the falling edge, but p33 is on the rising edge, p1 and p11, and p2 and p22 are aligned, then p1 and p2 are added to the first point set, and p11 and p22 are added to the second point set;

[0183] L313, for each group of adjacent data points in the first point set and the second point set that are in the curve, respectively calculate a first slope and a second slope;

[0184] For example, the data points p1 and p2 in the first point set are adjacent data points in the first fitting curve, so the slope between p1 and p2 (defined as the first slope) is calculated. Since the coordinates of p1 and p2 are known, the slope between the data points p1 and p2 can be calculated according to the Pythagorean theorem. This slope can characterize the performance changes of the battery module in successive mixing.

[0185] L314, calculates the mean of each first slope (defined as the first mean), and at the same time calculates the mean of each second slope (defined as the second mean), and calculates the sum of the first mean and the second mean (defined as the second sum), and then calculates the ratio of the first mean to the second sum (defined as the fourth ratio) as the second weight, and calculates the difference between "1" and the fourth ratio as the first weight.

[0186] L32, calculating the absolute value of the difference between the first weight and the second weight (defined as the second absolute value of the difference) as the second deviation amplitude.

[0187] Furthermore, when the absolute value of the difference between the first deviation amplitude and the second deviation amplitude (defined as a third difference absolute value) is smaller than a preset difference absolute value threshold, it is determined that the first deviation amplitude is similar to the second deviation amplitude.

[0188] In addition, in this embodiment, the types of battery modules in the difference battery pack include any one or more of iron-lithium batteries, ternary lithium batteries, and sodium-ion batteries. After each power supply to the power-consuming equipment, the BMS controls each battery module in the difference battery pack to switch to a power-off isolation state, in order to obtain mixed data after predicting the power demand of the power-consuming equipment, so that it is possible to screen the mixed battery pack.

[0189] In summary, in this embodiment, each time the battery modules are mixed and merged, the impact of the historical number of times they are mixed and merged and the feasibility of mixing and merging with the available balanced power group on the power loss of the finally constructed mixed and merged battery group on the power consumption of the electrical equipment is taken into consideration. Therefore, each mixing and merging is based on the condition that the performance of the battery module is improved to the greatest extent. The conditions for the battery module to join the dependent unit set set in this way can characterize the characteristics of the suspected failure of the battery module. Therefore, in this application, it is only necessary to determine in step L1 whether the number of times the battery module is added to the dependent unit set during the power supply interval between two full charges is greater than the preset number threshold, so as to quickly and more accurately identify whether the battery module is suspected of failure. In addition, by judging the similarity between the first deviation amplitude and the second deviation amplitude, it is possible to verify whether the suspected faulty battery is actually faulty.

[0190] It should be noted that the above specific implementations are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art should understand that various modifications, equivalent substitutions, changes, etc. can be made to the present invention. However, as long as these changes do not deviate from the spirit of the present invention, they should be within the scope of protection of the present invention. In addition, some terms used in the specification and claims of this application are not restrictive, but are only for the convenience of description.

Claims

1. A battery safety monitoring method based on BIT and BMS data interaction, characterized in that the steps include: L1, in the current charge and discharge cycle, the BMS chip determines whether the number of times the battery module joins the dependent unit set is greater than the preset number threshold. If yes, the battery module is determined to be a suspected faulty battery and added to the suspected faulty battery set, and then a fault verification instruction is generated and sent to the BIT chip before proceeding to step L2; If not, it is determined that the battery module has no suspected failure; L2, the BIT chip performs a mixed simulation on the suspected faulty battery in the suspected faulty battery set according to the fault verification instruction to obtain parameter values ​​of a first parameter and a second parameter for calculating the feasibility of mixed merging; L3, the BIT chip determines whether a first deviation of a first parameter value of the first parameter from a second parameter value of the second parameter is similar to a second deviation of a first weight corresponding to the first parameter from a second weight corresponding to the second parameter, If yes, it is determined that the suspected faulty battery is not faulty, and a first execution instruction is generated and sent to the BMS chip; If not, it is determined that the suspected faulty battery is faulty, and a second execution instruction is generated and sent to the BMS chip; L4, the BMS chip removes the suspected faulty battery from the suspected faulty battery set according to the first execution instruction, or moves the suspected faulty battery into the faulty battery set according to the second execution instruction; The feasibility of mixing and merging is: a weighted sum of a first ratio of a first internal resistance change of the simulated mixed and merged object to a second internal resistance change of the available balanced power source group from the start of mixing and merging to the battery terminal voltage balance between the simulated mixed and merged object and the available balanced power source group in the mixed and merged battery group, and a second ratio of a change in the available capacity of the battery of the simulated mixed and merged object to a charging time of the simulated mixed and merged object from the start of mixing and merging to the battery terminal voltage balance; In step L2, the method by which the BIT chip performs mixed simulation on the suspected faulty battery is: From all the previously mixed objects in the current charge and discharge cycle, the objects of the same type as the suspected faulty battery are screened out, and then the maximum mixed and balanced power supply group with the maximum mixing feasibility with each of the screened objects is extracted, and then mixed with the suspected faulty battery, and then mixed data is collected, including a first ratio of a first internal resistance change of the suspected faulty battery to a second internal resistance change of the maximum mixed and balanced power supply group from the start of mixing to the time when the battery terminal voltage is balanced as the first parameter value, and a second ratio of a battery available capacity change of the suspected faulty battery to the mixing time when the terminal voltage is balanced as the second parameter value; In step L3, the first deviation amplitude is: a first absolute value of a difference between a first proportion of the first parameter value in a first sum of the first parameter value and the second parameter value and a second proportion of the second parameter value in the first sum; The method for solving the second deviation amplitude in step L3 comprises the steps of: L31, assigning the first weight and the second weight corresponding to the first parameter and the second parameter respectively through curve fitting and slope solution; L32, calculating a second absolute value of a difference between the first weight and the second weight as the second deviation amplitude; When the absolute value of a third difference between the first deviation amplitude and the second deviation amplitude is less than a preset difference absolute value threshold, determining that the first deviation amplitude is similar to the second deviation amplitude; In step L1, the condition for the battery module to join the dependent unit set is: in the current charge and discharge cycle, the battery module as a member of the difference battery group is used as a historical mixing object at least twice; and as of now, the power supply loss of the historical mixing battery group containing the battery module to the same electrical equipment increases with the increase of the number of historical mixing times of the battery module; In step L31, the weighting method includes the steps of: L311, draw a first fitting curve and a second fitting curve of the first parameter and the second parameter respectively with respect to the historical mixing times, and align the data points on the first fitting curve and the second fitting curve, wherein the alignment method is: the first parameter value and the second parameter value used to calculate the same mixing feasibility have the same x-axis coordinate of the historical mixing times; L312, filter out data points that are on the rising edge or falling edge of the first fitting curve and the second fitting curve and have an alignment relationship, and add them to the first point set and the second point set respectively; L313, for each group of adjacent data points in the first point set and the second point set that are in the curve, respectively calculate a first slope and a second slope; L314, calculates the first mean of each of the first slopes and the second mean of each of the second slopes, and calculates the second sum of the first mean and the second mean, and then calculates the fourth ratio of the first mean to the second sum as the second weight, and calculates the difference between "1" and the fourth ratio as the first weight.

2. The battery safety monitoring method based on BIT and BMS data interaction according to claim 1 is characterized in that: In each charge and discharge cycle, after each power supply to the electrical device is completed, the method for the BMS battery management system to construct a hybrid battery pack for powering the electrical device next time includes the following steps: S1, according to the historical power supply data of the difference battery group to the electrical equipment in the current charge and discharge cycle, by calculating the minimum feasibility of mixing and merging, to find the object to be mixed and merged in the difference battery group; S2, constructing an available balanced power group for each of the quasi-mixed objects, and adding the group to the available balanced power group set associated with each of the quasi-mixed objects; S3, according to the power demand prediction result of the power-consuming device, identifying the available balanced power group that will supply power to the power-consuming device next time from each of the available balanced power group sets, and combining it with the associated proposed mixed-and-combined objects to form the mixed-and-combined battery group that will supply power to the power-consuming device next time; After each power supply is completed, the BMS battery management system switches each battery module in the difference battery pack to a power-off isolation state.

3. The battery safety monitoring method based on BIT and BMS data interaction according to claim 2 is characterized in that: In step S1, the method for finding the quasi-mixed object comprises the following steps: A1, obtaining a battery pack used to calculate the minimum hybrid feasibility; A2, calculating the minimum hybrid feasibility according to the historical hybrid data of the battery pack; A3, a simulation excitation source performs charging excitation on each remaining battery module in the difference battery pack except the dependent unit in the basis battery pack, so as to obtain the change rate of the available capacity of each battery module after the excitation; A4, determines whether the difference between the available capacity change rate of each battery module and the second ratio used to calculate the minimum hybrid feasibility is greater than a preset difference threshold. If so, the battery module is added to the set of simulated hybrid objects as the simulated hybrid object for powering the electrical equipment next time.

4. The battery safety monitoring method based on BIT and BMS data interaction according to claim 3 is characterized in that: The method for obtaining the calculation basis battery group in step A1 is: sorting the battery modules in the dependent unit set from large to small according to the number of historical mixing and merging times to form a sorted list, and then obtaining the historical mixed and merged battery group of the battery module ranked first in the sorted list at the last historical mixing and merging time as the basis battery group for calculating the minimum mixing and merging feasibility; In step A2, the minimum mixing feasibility is: a weighted sum of a first ratio of a first internal resistance change of the dependent unit to a second internal resistance change of the historical balanced power group from the start of mixing to the battery terminal voltage balance between the dependent unit in the battery pack and the historical balanced power group, and a second ratio of a change in the available battery capacity of the dependent unit to the charging time of the dependent unit from the start of mixing to the battery terminal voltage balance.

5. The battery safety monitoring method based on BIT and BMS data interaction according to claim 2 is characterized in that: In step S2, the method for constructing the available balanced power supply group for each of the pseudo-mixed objects comprises the following steps: B1, specifying the quasi-mixed object used to construct the proposed balanced power source group from the quasi-mixed object set; B2, randomly extracting the same number of battery modules as the historical balanced power sources in the historical balanced power source group in the battery group used to calculate the minimum mixed feasibility from the specified remaining set of the proposed mixed objects as the proposed balanced power sources; B3, connecting the extracted balanced power sources to be used in parallel to form a balanced power group to be used, and then mixing the balanced power group to be used with the object to be mixed and merged, and monitoring the mixed and merged data until each battery module in the balanced power group to be used reaches a battery terminal voltage balance state; B4, calculating the feasibility of mixing and merging the planned balanced power source group and the planned mixed and merged object according to the mixed and merged data; B5, judging whether the mixed-merge feasibility is greater than the minimum mixed-merge feasibility, If yes, determining that the proposed balanced power group is the available balanced power group available to the proposed mixed and merged object, and adding it to the available balanced power group set associated with the proposed mixed and merged object; If not, the process returns to step B2 to extract battery modules again to form different balanced power groups to be used, until it is no longer possible to form different balanced power groups to be used.

6. The battery safety monitoring method based on BIT and BMS data interaction according to claim 5 is characterized in that: In step S3, the method of identifying the available balanced power group for supplying power to the electric device next time from the available balanced power group set associated with each of the objects to be mixed and merged comprises the following steps: C1, filtering out the available balanced power groups whose power supply is less than the predicted power demand in the sets of available balanced power groups respectively associated with the proposed mixed-merging objects, and then arranging the remaining available balanced power groups from high to low according to the mixed-merging feasibility with the associated proposed mixed-merging objects to form a first list; C2, calculating the difference between the battery performance of the pseudo-mixed objects associated with each of the available balanced power groups remaining after filtering in step C1 and the dependent units in the battery group, and arranging the pseudo-mixed objects from high to low according to the difference to form a second list; C3: for the second element in the second list that has the same ranking as the first element in the first list, determine whether the number of element combinations that have an association relationship between the second element and the first element is at least "1" If so, extract the element combination at the front of the sorting list, mix and merge them, and use them as the mixed and merged battery group for supplying power to the electrical device next time; If not, the proposed hybrid object ranked first in the first list is hybridized with the available balanced power source group with the maximum hybrid feasibility to form the hybrid battery group for the next power supply.

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