Cloud full-time equalization capacity estimation method based on single voltage and electronic device

Abstract

The invention discloses a cloud full-time equalization capacity estimation method based on single voltage and an electronic device, relates to the technical field of dynamic management and control of batteries, and solves the technical problem that deep equalization is difficult to realize in a limited time window due to the fact that a passive equalization mode adopted in the prior art is limited by the thermal management capability of an equalization circuit. According to the method, the charging voltage curve is constructed by acquiring the charging starting time and the charging ending time of the energy storage battery pack and voltage values and current values at different moments in the charging process; judging whether the voltage condition and the stable current duration of the corresponding single body are qualified or not; judging whether the residual capacities of the corresponding monomers before and after charging are consistent; calculating a voltage difference value of the residual capacity before and after charging, and primarily screening a balancing monomer list based on the voltage difference value; obtaining the balanced battery capacity of the monomer from the list based on the starting moment; determining an equalization scheme according to the equalization battery capacity and the equalization monomer list; according to the invention, the equalization effect and the stability of the energy storage system are improved.

Description

Technical Field

[0001] The present invention belongs to the field of battery dynamic management and control, relates to battery equalization technology, and specifically is a cloud full-time equalization capacity estimation method and an electronic device based on single-cell voltage. Background Art

[0002] Energy storage battery packs are the basic components of energy storage systems. To meet a certain voltage level, a large number of single cells are usually connected in series for combination; in actual application scenarios, due to the factor of the single-cell series structure, combined with the natural differences in manufacturing processes, material properties, etc. of each single cell, as well as self-discharge differences, even in the same charge-discharge environment, the charging or discharging time of the single cells to full charge or full discharge will be different. Therefore, after a period of use, the state of charge between the single cells becomes inconsistent, which is intuitively manifested as the voltage of some single cells being relatively high while the voltage of another part of the single cells being relatively low, bringing negative impacts to the performance stability and efficient operation of the entire energy storage system.

[0003] Regarding the consistency differences of single cells in the energy storage battery pack, the application of equalization technology is crucial; currently, the commonly used passive equalization means in the prior art are mostly implemented at the end stage of battery charging. At this stage, the relationship between battery voltage and battery state of charge is relatively obvious. The prior art uses a voltage difference detection mechanism to identify the voltage differences between battery single cells and discharge and equalize the high-voltage single cells; however, it does not consider that the passive equalization mode is limited by the power density and thermal management ability of the equalization circuit, resulting in low equalization efficiency, large energy loss, and difficulty in achieving deep equalization within a limited time window. At the same time, due to the limited computing power and storage resources of the embedded controller in the prior art, it is difficult for the system to build an accurate battery model and perform real-time health status assessment, resulting in the inability to accurately estimate the differential equalization capacity required for each single cell through dynamic parameter identification, and causing technical problems such as the inability to eliminate the virtual voltage phenomenon caused by the polarization characteristic differences of single cells and the difficulty in achieving global optimization of the energy utilization efficiency of the battery pack.

[0004] The present invention provides a cloud full-time equalization capacity estimation method and an electronic device based on single-cell voltage to solve the above technical problems. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art; for this purpose, the present invention proposes a cloud full-time equalization capacity estimation method and an electronic device based on single-cell voltage, which are used to solve the technical problem that the passive equalization mode adopted in the prior art is limited by the power density and thermal management ability of the equalization circuit, resulting in difficulty in achieving deep equalization within a limited time window.

[0006] To achieve the above object, the first aspect of the present invention provides a cloud full-time equalization capacity estimation method based on monomer voltage, including: S100: Obtain the charging start time, end time, voltage values and current values at different moments during the charging process of the energy storage battery pack, and construct a charging voltage curve; S200: For each monomer in the energy storage battery pack, when the voltage condition and the stable current duration of the monomer are both qualified, obtain the remaining capacity of the monomer before and after charging; S300: Determine whether the remaining capacity of the monomer before and after charging is consistent; if yes, calculate the voltage difference of the remaining capacity before and after charging, and preliminarily screen the equalization monomer list based on the voltage difference; if not, output a label indicating that the remaining capacity of the monomer is inconsistent; S400: If the remaining capacity of the monomers in the energy storage battery pack before and after charging is consistent, obtain the starting time pair list for the translation of the charging voltage curve; obtain the equalization battery capacity of the monomer based on the starting time pair list; determine the equalization scheme according to the equalization battery capacity and the equalization monomer list.

[0007] Preferably, before obtaining the remaining capacity of the monomer before and after charging when the voltage condition and the stable current duration of the monomer are both qualified, it further includes: The specific steps for determining whether the voltage condition of the monomer is qualified include: S210: Generate a sampling time set T = {1, 2, 3,..., n} based on the charging start time and end time of the energy storage battery pack; mark the set of voltage conditions of the monomers in all energy storage battery packs at several moments as; where n represents the number of sampling times; represents the voltage set of all monomers at the t-th moment; is the voltage of the i-th monomer corresponding to the t-th moment, and the monomer set I of the energy storage battery pack = {1, 2, 3,..., m}, and m represents the number of monomers; S211: Mark the minimum value among all monomer voltages corresponding to the first moment as the starting minimum voltage; S212: Mark the maximum value among all monomer voltages corresponding to the n-th moment as the ending maximum voltage; S213: If the starting minimum voltage is less than or equal to the preset voltage lower limit threshold and the ending maximum voltage is greater than or equal to the preset voltage upper limit threshold, determine that the voltage condition of the monomer is qualified.

[0008] Preferably, before obtaining the remaining capacity of the monomer before and after charging when the voltage condition and the stable current duration of the monomer are both qualified, it further includes: The specific steps for determining whether the stable current duration of the monomer is qualified include: S220: Divide the difference between the current moment current and the previous moment current by the previous moment current to obtain the current fluctuation ratio value at the current moment ; Construct a fluctuation ratio list through the current fluctuation ratio value ; S221: Through the expression Obtain the current segment endpoint list; S222: Calculate the maximum time difference between adjacent endpoints in the current segment endpoint list through the formula ; Wherein, is the preset sampling time interval; represents the t-th element in the current segment endpoint list ST, and L represents the number of elements in the current segment endpoint list ST; S223: Judge whether the maximum time difference is less than the preset time length threshold; if yes, mark the stable current duration of the monomer as unqualified; if not, mark the stable current duration of the monomer as qualified.

[0009] It should be noted that the charging time of the energy storage from SOC = 0% to SOC = 100% at night is 5 hours, so the preset time length threshold is less than 5 hours.

[0010] The present invention is beneficial to making the observed stable current time during charging as long as possible by setting the time length threshold; since the drastic change of the current will cause the drastic change of the voltage, judging whether the maximum time difference is less than the preset time length threshold to obtain the stable current duration that meets the conditions is beneficial to obtaining a relatively reasonable result by implementing curve translation subsequently.

[0011] Preferably, judging whether the remaining capacity of the monomer before and after charging is the same includes: S310: Obtain the minimum voltage monomer and the maximum voltage monomer at each moment during charging and number the monomers; Mark the monomer number that appears most frequently in the minimum voltage monomers as monomer x, and mark the monomer number that appears most frequently in the maximum voltage monomers as monomer y; wherein, the minimum voltage monomer refers to the monomer corresponding to the minimum value among all monomer sampling voltages at each moment, and the maximum voltage monomer refers to the monomer corresponding to the maximum value among all monomer sampling voltages at each moment; S311: Preset a condition set, and judge whether the remaining capacity of the monomer does not meet the condition set; if yes, mark the remaining capacity of the monomer before and after charging as the same; If not, mark the remaining capacity of the monomer before and after charging as inconsistent; wherein, the preset condition set includes: preset condition one, preset condition two, and preset condition three; The preset condition one is: monomer x is the maximum voltage monomer at the end of charging; The second preset condition is: cell y is the cell with the minimum voltage at the end of charging; The preset condition three is that the monomer with the smallest starting voltage is consistent with the monomer with the largest ending voltage.

[0012] In the present invention, if the remaining capacity of the monomers is consistent and the charging current of all monomers in series is the same, then the amount of electricity charged is the same, and the voltage change should also be basically the same, so the monomer voltage performance after charging is consistent with before; if it is determined that the remaining capacity of the monomer voltage meets the condition set, it is considered that there is a certain inconsistency in the remaining capacity between the monomers. At this time, the monomer is not suitable for balancing processing to a certain extent, and subsequent calculations are not performed to avoid unnecessary energy consumption and potential damage to the battery, thereby improving system efficiency and extending the life of the battery pack.

[0013] Preferably, the preliminary screening of the balancing monomer list based on the voltage difference includes: S320: Retrieve monomer a and the minimum starting voltage corresponding to monomer a ; Among them, monomer a is the monomer corresponding to the minimum starting voltage; S321: By formula The voltage difference between the ith monomer and monomer a at the start time is calculated; where, Indicates the voltage value corresponding to the i-th monomer at the starting time; S322: Statistical voltage difference A list of monomers g whose voltage difference is greater than a preset starting voltage difference threshold; S323: By formula The voltage difference between the ith monomer and monomer a at the end time is calculated; where, Indicates the voltage value corresponding to the i-th monomer at the end time; S324: Statistical voltage difference List h of cells whose voltage difference is greater than the preset end voltage difference threshold; let the union of lists g and h be list f of cells to be balanced; Determine whether the list to be balanced f is empty; if so, output the label that the monomer consistency does not need to be balanced; if not, mark it as completing the initial screening of the balanced monomer list.

[0014] In the present invention, the relationship between the remaining power and voltage of the monomers in a period of time between the start and end of charging is relatively obvious. The monomers with larger voltages have more remaining power, so the voltage difference reflects the size of the capacity difference to a certain extent. By statistically listing the monomers whose voltage differences are greater than the preset end voltage difference threshold, that is, selecting the monomers with larger voltage differences for calculation and balancing, it is helpful to reduce some calculation amounts.

[0015] Preferably, the obtaining of a list of starting time pairs for charging voltage curve shifting includes: S410: Mark the cell with the minimum voltage at the end of charging as cell b; S411: Retrieve the list of balanced cells after preliminary screening and traverse the list of cells to be balanced. Mark the currently calculated cell as cell k, and use the charging voltage curve of cell k as the reference charging voltage curve; mark the start time of the reference charging voltage curve segment selected by cell k as s_k; calculate the start time of the segment with the maximum similarity corresponding to cell b through the function wherein, represents the Manhattan distance between cell b at the set time one and cell k at the set time two, and l_k represents the length of the reference charging voltage curve segment selected by cell k; S412: Mark the pair of start times for translating the reference charging voltage curve as (s_k, s_b); S413: Select the voltage data of the first P1% of cell k as the reference charging voltage curve segment k1, mark the start time of k1 as s_k1, and select all the voltage data of cell b as the charging voltage curve b1 to be translated; where 0 < P1 < 50; S414: Traverse all the times of the charging voltage curve b1 to be translated. Let the currently traversed time be s1. Select the data segment with the same length as the reference charging voltage curve segment k1 starting from the current time s1, calculate the Manhattan distance from the reference curve segment k1, and select the start time with the minimum Manhattan distance, denoted as s1_b1; then mark the pair of start times for translating the charging voltage curve b1 to be translated as (s1_k1, s1_b1); S415: Select the data of cell k from P1% to P2% as the reference charging voltage curve segment k2, and the start time of k2 is s2_k2. Select all the voltage data of cell b as the charging voltage curve b2 to be translated; where P1 < P2 < 100; S416: Traverse all the times of the charging voltage curve b2 to be translated. Let the currently traversed time be s2. Select the data with the same length as the reference charging voltage curve segment k2 starting from s2, and calculate the Manhattan distance from the reference charging voltage curve segment k2; select the start time with the minimum Manhattan distance, denoted as s2_b2; obtain the pair of start times (s2_k2, s2_b2); S417: Then the list of pairs of start times is {(s1_k1, s1_b1), (s2_k2, s2_b2)}.

[0016] Through the P1 - P2 segmentation strategy, the present invention decomposes and independently analyzes the charging voltage curve, reducing the cumulative error caused by overall translation.

[0017] Preferably, the method for obtaining the Manhattan distance includes: Manhattan distance Obtaining method: ; In the formula, represents the length of the reference charging voltage curve segment k1, represents the voltage of cell k at time represents the voltage of cell b at time represents the counting subscript of the voltage sampling time corresponding to the reference curve segment k1.

[0018] Preferably, obtaining the equalized battery capacity of the cell based on the start time pair list includes: S420: Retrieve the start time pair list, and obtain the charging current value between the start time pairs (s1_k1, s1_b1) in the start time pair list. Calculate the battery capacity capacity1 according to the ampere-hour integration method; Obtain the charging current value between the start time pairs (s2_k2, s2_b2) in the start time pair list. Calculate the battery capacity capacity2 according to the ampere-hour integration method; S421: Take the average value of the battery capacities of the two time pairs as the equalized battery capacity of the cell; S422: Repeat steps S410 - S417 and steps S420 - S421 to calculate the equalized battery capacity of all cells to be equalized compared with cell b.

[0019] Preferably, determining the equalization scheme according to the equalized battery capacity and the equalized cell list includes: Construct the execution limit of the battery management system BMS. Among them, the BMS execution limit includes: the equalized battery capacity can at most turn on half of all cells and the corresponding equalized cells cannot be adjacent; Based on the BMS execution limit, sort the equalized cells corresponding to the equalized battery capacity in descending order, construct and initialize the final equalization list as empty, and traverse all the sorted equalized cells in turn; Judge whether there is a cell adjacent to the currently traversed cell in the final equalization list; if yes, skip the currently traversed cell; if no, add the currently traversed cell to the final equalization list; until the number of equalized cells is greater than the limit number or the sorted equalized cell list is traversed, output the final equalized cell list and the corresponding equalization capacity as the equalization scheme, and end the algorithm; Execute the actual equalization operation through the BMS according to the equalization scheme.

[0020] It should be noted that when passive equalization heat dissipation is adopted, a resistor or an equivalent energy-consuming component is connected in parallel to each single cell, and the single cell forms a loop with the corresponding parallel resistor by controlling the switch, which is conducive to the single cell discharging through the resistor, dissipating the excess energy in the form of heat, and causing other battery failures due to excessive heat generation of the resistor. By setting the BMS execution limit in this application, the resistor discharge can be effectively restricted, thereby avoiding other battery failures caused by excessive heat generation of the resistor.

[0021] To achieve the above object, the second aspect of the present invention provides an electronic device for estimating the cloud full-time equalization capacity based on the single cell voltage, including: a memory and a processor, and executable instructions of the processor are stored in the memory; wherein, the processor is configured to execute the implementation of the cloud full-time equalization capacity estimation based on the single cell voltage provided in the first aspect by executing the executable instructions.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Through the charging voltage data uploaded in real time by the energy storage battery pack, the present invention migrates complex calculation tasks to the cloud for processing. Relying on the powerful computing power and sufficient storage resources of the cloud, combined with the voltage curve translation method, the equalization capacity of the single cell can be calculated quickly and efficiently; in this way, the limitation of traditional passive equalization is broken, providing strong technical support for realizing the equalization management of the energy storage battery pack in all time periods and extending its service life; relying on the strong adaptability of the cloud, based on the charging voltage data of the energy storage battery pack, by deeply analyzing dynamic changes such as voltage curve translation, the present invention can set appropriate equalization strategies according to energy storage devices of different specifications and different application scenarios, achieving relatively good versatility and compatibility; in addition, the cloud computing equalization capacity also has good scalability. With the continuous expansion of the scale of the energy storage battery pack and the increasing diversification of application scenarios, the cloud can easily handle the growth of data volume and the improvement of calculation complexity, always ensuring the accuracy and timeliness of equalization capacity calculation.

[0023] 2. The present invention deeply analyzes the charging voltage data of lithium iron phosphate energy storage battery packs through the cloud, accurately captures the offset time between monomers based on the translation of voltage curves, and further calculates the equalization capacity in combination with current information. This method considers multi-dimensional information such as the voltage change trend and time during the charging process of monomers, can relatively accurately measure the true capacity difference between monomers, enables the calculated equalization capacity to meet the actual needs, and provides a reliable basis for subsequent equalization operations; the present invention analyzes the charging voltage data and the corresponding equalization calculation logic through the cloud, breaks the time limitation of traditional passive equalization, and realizes the full-time equalization management of energy storage battery packs; by virtue of the real-time and uninterrupted operation characteristics of the cloud, regardless of whether the energy storage is in the charging, discharging or static state, equalization operations can be carried out in a timely manner according to the calculated equalization capacity, effectively maintaining the consistency between monomers, improving the equalization effect as a whole, and ensuring the more stable and efficient operation of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0025] Figure 1 It is a schematic flow chart of a method for estimating the full-time equalization capacity of monomer voltages provided by the present invention; Figure 2 It is a schematic diagram of the specific steps of another method for estimating the full-time equalization capacity of monomer voltages provided by the present invention; Figure 3 It is a schematic diagram of the voltage curve translation result of the present invention; Figure 4 It is a schematic diagram of the specific steps of another method for estimating the full-time equalization capacity of monomer voltages provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0027] Please refer to Figure 1 , the first aspect embodiment of the present invention provides a method for estimating the full-time equalization capacity of monomer voltages based on cloud, including: S100: Obtain the charging start time, end time of the energy storage battery pack, as well as the voltage values and current values at different moments during the charging process, and construct a charging voltage curve; S200: For each single cell in the energy storage battery pack, when both the voltage condition and the stable current duration of the single cell are qualified, obtain the remaining capacity of the single cell before and after charging; S300: Determine whether the remaining capacity of the corresponding single cell before and after charging is consistent; if yes, calculate the voltage difference of the remaining capacity before and after charging, and initially screen the list of balanced single cells based on the voltage difference; if not, output a label indicating that the remaining capacity of the corresponding single cell is inconsistent; S400: If the remaining capacity of the single cells in the energy storage battery pack before and after charging is consistent, obtain a list of starting moments for the translation of the charging voltage curve; obtain the balanced battery capacity of the corresponding single cells based on the list of starting moments; determine a balancing scheme according to the balanced battery capacity and the list of balanced single cells.

[0028] Please refer to Figure 2 , the solution described in S200 above can be specifically implemented through the following steps S210 - S213 and steps S220 - S223. Among them, S210 - S213 are used to determine whether the voltage condition of the single cell is qualified, and S220 - S223 are used to determine whether the stable current duration of the single cell is qualified.

[0029] First, the process of determining whether the voltage condition of the single cell is qualified will be described in combination with the following S210 - S213: S210: Generate a sampling time set T = {1, 2, 3,..., n} based on the charging start time and end time of the energy storage battery pack; mark the set of the voltage conditions of all single cells in the energy storage battery pack at several moments as; where n represents the number of sampling times; represents the voltage set of all single cells at the t-th moment; is the voltage of the i-th single cell corresponding to the t-th moment, and the single cell set I of the energy storage battery pack = {1, 2, 3,..., m}, and m represents the number of single cells; S211: Mark the minimum value among all the single cell voltages corresponding to the first moment as the starting minimum voltage; S212: Mark the maximum value among all the single cell voltages corresponding to the n-th moment as the ending maximum voltage; S213: If the starting minimum voltage is less than or equal to the preset voltage lower limit threshold and the ending maximum voltage is greater than or equal to the preset voltage upper limit threshold, determine that the voltage condition of the single cell is qualified; Secondly, the process of determining whether the stable current duration of the single cell is qualified will be described in combination with the following S220 - S223: S220: Divide the difference between the current at the current moment and the current at the previous moment by the current at the previous moment to obtain the current fluctuation ratio value at the current moment ; Construct a fluctuation ratio list based on the current fluctuation ratio value ; S221: Obtain the list of current segment endpoints through the expression ; S222: Calculate the maximum time difference between adjacent endpoints in the list of current segment endpoints through the formula ; where is the preset sampling time interval; represents the t-th element in the list of current segment endpoints ST, and L represents the number of elements in the list of current segment endpoints ST; S223: Determine whether the maximum time difference is less than the preset time length threshold; if yes, mark the stable current duration of the corresponding monomer as unqualified; if no, mark the stable current duration of the corresponding monomer as qualified.

[0030] For example, there is an energy storage battery pack being charged. The energy storage terminal accurately records the start and end times of charging based on its own data platform, and generates a sampling time set based on this ; Through the stable communication link established with the cloud, these key time information are transmitted to the cloud; after receiving the relevant instructions, the cloud accurately extracts the data of this charging segment of the energy storage battery pack from the massive data, and fully transmits it into the cloud environment for subsequent processing; these data cover the voltage conditions of all monomers at each moment, denoted as ; The cloud processes the monomer voltages sampled at the start and end times, and calculates the start minimum voltage and its corresponding monomer a and the end maximum voltage ; Set the voltage lower limit threshold to 3200 mV and the voltage upper limit threshold to 3450 mV; Currently, the start minimum voltage of the lithium iron phosphate monomers in all energy storage battery packs is less than the voltage lower limit threshold, and the end maximum voltage is greater than the voltage upper limit threshold; The cloud evenly calculates the fluctuation ratio values of all adjacent currents, and the preset current fluctuation threshold is 10%; If the current fluctuation ratio at the current moment is greater than 10%, it is considered that a significant current fluctuation has occurred from the previous moment to the current moment. At this time, the two data points corresponding to the current moment and the previous moment are divided into different segments, that is, the current moment is the start moment of a new segment; find the moments in all segments where the fluctuation ratio value is greater than the current fluctuation threshold to form a list of current segment endpoints, add the start moment and the end moment to the head and tail of the list of current segment endpoints respectively, and through the formula calculate the maximum time difference between adjacent endpoints in the list of current segment endpoints; at this moment, the maximum time difference is greater than the preset time length threshold of 3 hours; then mark the stable current duration of the corresponding monomer as qualified.

[0031] It should be noted that since there is no current at the previous moment for the first data point, it is supplemented to the list of endpoints of the current segment; the end time is supplemented to calculate the duration of the last segment.

[0032] Please refer to Figure 4 , for the specific steps of another method for estimating the full-time cloud balancing capacity of the monomer voltage: S410: Mark the monomer with the minimum voltage at the end of charging as monomer b; S411: Retrieve the list of balanced monomers after preliminary screening and traverse the list to be balanced. Mark the monomer to be calculated currently as monomer k, and use the charging voltage curve of monomer k as the reference charging voltage curve; mark the start time of the reference charging voltage curve segment selected by monomer k as s_k; through the function Calculate the start time of the segment with the maximum similarity corresponding to monomer b, where represents the Manhattan distance between monomer b at the set time one and monomer k at the set time two, and l_k represents the length of the reference charging voltage curve segment selected by monomer k; S412: Mark the pair of start times for translating the reference charging voltage curve as (s_k, s_b); S413: Select the first P1% of the voltage data of monomer k as the reference charging voltage curve segment k1, mark the start time of k1 as s_k1, and select all the voltage data of monomer b as the charging voltage curve b1 to be translated; where 0 < P1 < 50; S414: Traverse all the times of the charging voltage curve b1 to be translated. Let the current time traversed be s1. Select the data segment with the same length as the reference charging voltage curve segment k1 starting from the current time s1, calculate the Manhattan distance from the reference curve segment k1, and select the start time with the minimum Manhattan distance, denoted as s1_b1; then mark the pair of translation start times of the charging voltage curve b1 to be translated as (s1_k1, s1_b1); Manhattan distance Obtaining method: ; In the formula, represents the length of the reference charging voltage curve segment k1, represents the voltage of monomer k at time represents the voltage of monomer b at time represents the counting subscript of the voltage sampling time corresponding to the reference curve segment k1; S415: Select the data of monomer k from P1% to P2% as the reference charging voltage curve segment k2, with the starting time of k2 being s2_k2. Select all voltage data of monomer b as the charging voltage curve b2 to be translated; where P1 < P2 < 100; S416: Traverse all times of the charging voltage curve b2 to be translated. Let the currently traversed time be s2. Select the data with the same length as the reference charging voltage curve segment k2 starting from s2, and calculate the Manhattan distance from the reference charging voltage curve segment k2. Select the starting time with the smallest Manhattan distance and denote it as s2_b2. Obtain the starting time pair (s2_k2, s2_b2); S417: Then the starting time pair list is {(s1_k1, s1_b1), (s2_k2, s2_b2)}; S420: Retrieve the starting time pair list, and obtain the charging current value between the starting time pair (s1_k1, s1_b1) in the starting time pair list. Calculate the battery capacity capacity1 according to the ampere-hour integration method; Obtain the charging current value between the starting time pair (s2_k2, s2_b2) in the starting time pair list, and calculate the battery capacity capacity2 according to the ampere-hour integration method; S421: Take the average value of the battery capacities of the two time pairs as the balanced battery capacity of the corresponding monomer; S422: Repeat steps S410 - S417 and steps S420 - S421 to calculate the balanced battery capacity of all monomers to be balanced compared with monomer b. Take the final balanced monomer list and the corresponding balanced capacities as the balancing scheme.

[0033] For example, select the voltage data of the first 33% of monomer k as the reference curve segment k1, denote its starting time as s_k1, and select all voltage data of monomer b as the curve b1 to be translated; Traverse all times of the curve b1 to be translated. Let the currently traversed time be s. Select the data segment with the same length as the reference curve segment k1 starting from s, calculate the Manhattan distance from the reference curve segment k1, and record the starting time s and the corresponding Manhattan distance. Select the starting time with the smallest Manhattan distance and denote it as s_b1. Obtain the starting time pair (s_k1, s_b1); Figure 3As shown in Figure (a), the blue solid line represents the reference curve, and the yellow dashed line represents the curve b1 to be translated; the part between the red crosses in the blue solid line represents the reference curve segment k1, and the part between the red asterisks in the yellow dashed line represents the part with the minimum Manhattan distance obtained by traversing the curve to be translated, denoted as the translation segment; the subgraph in the lower right corner is the translation schematic diagram of these two parts, where the green dotted line represents the translated curve drawn according to the translation segment. It can be seen that the blue solid line and the green dotted line in the subgraph have a high degree of coincidence, which indicates that the reference curve segment k1 and the translation segment have a high degree of similarity; record the starting time of the two to form a starting time pair; Select the data of monomer k from 33% to 66% as the reference curve segment k2, and record its starting time as s_k2. Select all the voltage data of monomer b as the curve b2 to be translated; Similarly, traverse all the times of the curve b2 to be translated. Let the currently traversed time be s. Select the data with the same length as the reference curve segment k2 starting from s, and calculate the Manhattan distance from the reference curve segment k2. The two voltage curves are translated left and right in time. Here, the curve b2 to be translated needs to be shifted to the left to be approximately coincident with the reference curve segment k2. Therefore, it can be directly traversed starting from s_k2, and the part before s_k2 can be discarded to reduce the amount of calculation; select the starting time with the minimum Manhattan distance, denoted as s_b2; obtain the starting time pair (s_k2, s_b2); as Figure 3 As shown in Figure (b), similarly, the blue solid line represents the reference curve, and the yellow dashed line represents the curve b2 to be translated; the part between the red crosses in the blue solid line represents the reference curve segment k2, and the part between the red asterisks in the yellow dashed line represents the part with the minimum Manhattan distance obtained by traversing the curve to be translated, denoted as the translation segment; the subgraph in the lower right corner is the translation schematic diagram of these two parts, where the green dotted line represents the translated curve drawn according to the translation segment. It can be seen that the blue solid line and the green dotted line in the subgraph have a high degree of coincidence, which indicates that the reference curve segment k2 and the translation segment have a high degree of similarity; record the starting time of the two to form a starting time pair; Thus, the list of starting time pairs is obtained as {(s_k1, s_b1), (s_k2, s_b2)}; Obtain the current data between the time pairs (s_k1, s_b1), and calculate the capacity according to the ampere-hour integration method: calculate the difference list of adjacent times, calculate the average current list of adjacent times, multiply the time difference list and the average current list one by one and then sum, and convert the unit to ampere-hour, that is, the balanced capacity calculated at this time pair is denoted as capacity1; similarly, calculate the balanced capacity of the time pair (s_k2, s_b2) and denote it as capacity2; take the average of the calculation results of the two time pairs (capacity1 + capacity1) / 2 as the balanced capacity of this single cell; use the final balanced single cell list and the corresponding balanced capacity as the balancing scheme.

[0034] The second aspect of the present invention provides an electronic device for estimating the full-time balanced capacity of a cloud based on the voltage of a single cell, including: a memory and a processor, and the memory stores executable instructions of the processor; wherein, the processor is configured to execute the implementation of the full-time balanced capacity estimation of the cloud based on the voltage of a single cell provided in the first aspect by executing the executable instructions.

[0035] Some of the data in the above formula are calculated by removing the dimension and taking its numerical value. The formula is a formula that is closest to the actual situation obtained through software simulation of a large amount of collected data; the preset parameters and preset thresholds in the formula are set by those skilled in the art according to the actual situation or obtained through simulation of a large amount of data.

[0036] The working principle of the present invention: The present invention obtains the charging start time, end time, voltage values and current values at different times during the charging process of the energy storage battery pack, and constructs a charging voltage curve; obtains the voltage conditions of the single cells in the energy storage battery pack and judges whether the voltage conditions of the corresponding single cells are qualified; judges whether the stable current duration of the corresponding single cell is qualified; obtains the remaining capacity of the single cell before and after charging; judges whether the remaining capacity of the corresponding single cell before and after charging is consistent; if so, calculate the voltage difference of the remaining capacity before and after charging, and initially screen the balanced single cell list based on the voltage difference; if not, output a label indicating that the remaining capacity of the corresponding single cell is inconsistent; if the remaining capacity of the single cells in the energy storage battery pack is consistent before and after charging, obtain the list of starting time pairs for the translation of the charging voltage curve; obtain the balanced battery capacity of the corresponding single cell based on the list of starting time pairs; determine the balancing scheme according to the balanced battery capacity and the balanced single cell list.

[0037] The above embodiments are only used to illustrate the technical method of the present invention and not to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical method of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A cloud-based full-time balanced capacity estimation method based on single cell voltage, characterized in that: include: S100: Obtain charging start time, end time, and voltage and current values ​​at different times during the charging process of the energy storage battery pack, and construct a charging voltage curve; S200: for each cell in the energy storage battery pack, when the voltage condition and the stable current duration of the cell are both qualified, obtaining the remaining capacity of the cell before and after charging; S300: Determine whether the remaining capacity of the monomer is consistent before and after charging; If yes, the voltage difference of the remaining capacity before and after charging is calculated, and the balanced monomer list is preliminarily screened based on the voltage difference; If not, a label indicating that the remaining capacity of the monomer is inconsistent is output; S400: If the remaining capacities of the cells in the energy storage battery pack are consistent before and after charging, a list of starting time pairs for shifting the charging voltage curve is obtained; based on the list of starting time pairs, a balanced battery capacity of the cells is obtained; and a balanced solution is determined according to the balanced battery capacity and the balanced cell list.

2. The method for estimating full-time balanced capacity in the cloud based on single cell voltage according to claim 1, characterized in that: When the voltage condition and the stable current duration of the monomer are both qualified, before obtaining the remaining capacity of the monomer before and after charging, the method further includes: The specific steps of judging whether the voltage condition of the monomer is qualified include: S210: Generate a sampling time set T={1, 2, 3, ..., n} based on the start time and end time of charging the energy storage battery pack; mark the set of voltage conditions of all cells in the energy storage battery pack at several times as ; Where n represents the number of sampling times; represents the voltage set of all monomers at time t; is the voltage of the i-th cell corresponding to the t-th moment, the cell set of the energy storage battery pack is I={1, 2, 3, …, m}, where m represents the number of cells; S211: marking the minimum value of all monomer voltages corresponding to the first moment as the starting minimum voltage; S212: marking the maximum value of all monomer voltages corresponding to the nth moment as the ending maximum voltage; S213: If the starting minimum voltage is less than or equal to a preset voltage lower limit threshold, and the ending maximum voltage is greater than or equal to a preset voltage upper limit threshold, it is determined that the voltage condition of the cell is qualified.

3. The method for estimating full-time balanced capacity in the cloud based on cell voltage according to claim 1, characterized in that: When the voltage condition and the stable current duration of the monomer are both qualified, before obtaining the remaining capacity of the monomer before and after charging, the method further includes: The specific steps of judging whether the stable current duration of the monomer is qualified include: S220: Divide the difference between the current at the current moment and the current at the previous moment by the current at the previous moment to obtain the current fluctuation ratio value at the current moment ; Construct a fluctuation ratio list through the current fluctuation ratio value ; S221: searching for the time corresponding to the current fluctuation ratio value greater than the preset current fluctuation threshold in all fluctuation ratio lists to form a current segment endpoint list, and adding the preset start time and end time to the beginning and end of the current segment endpoint list respectively; S222: By formula Calculate the maximum time difference between adjacent endpoints in the current segment endpoint list; where, is the preset sampling time interval; represents the tth element in the current segment endpoint list ST, and L represents the number of elements in the current segment endpoint list ST; S223: Determine whether the maximum time difference is less than a preset time length threshold; if yes, mark the stable current duration of the monomer as unqualified; if no, mark the stable current duration of the monomer as qualified.

4. The method for estimating full-time balanced capacity in the cloud based on single cell voltage according to claim 1, characterized in that: The determining whether the remaining capacity of the monomer is consistent before and after charging includes: S310: Obtain the minimum voltage monomer and the maximum voltage monomer at each moment in the charging process and number the monomers; mark the monomer number that appears most frequently among the minimum voltage monomers as monomer x, and mark the monomer number that appears most frequently among the maximum voltage monomers as monomer y; wherein the minimum voltage monomer is represented by the monomer corresponding to the minimum value of all monomer sampling voltages at each moment, and the maximum voltage monomer is represented by the monomer corresponding to the maximum value of all monomer sampling voltages at each moment; S311: Preset a set of conditions, determine whether the remaining capacity of the monomer does not meet the set of conditions; if yes, mark the remaining capacity of the monomer before and after charging as consistent; If not, the remaining capacity of the monomer before and after charging is marked as inconsistent; wherein the preset condition set includes: preset condition one, preset condition two and preset condition three; The first preset condition is: cell x is the cell with the maximum voltage at the end of charging; The second preset condition is: cell y is the cell with the minimum voltage at the end of charging; The preset condition three is that the monomer with the smallest starting voltage is consistent with the monomer with the largest ending voltage.

5. The method for estimating full-time balanced capacity in the cloud based on cell voltage according to claim 2, characterized in that: The initial screening of the balancing monomer list based on the voltage difference includes: S320: Retrieve monomer a and the minimum starting voltage corresponding to monomer a ; Among them, monomer a is the monomer corresponding to the minimum starting voltage; S321: By formula The voltage difference between the ith monomer and monomer a at the start time is calculated; where, Indicates the voltage value corresponding to the i-th monomer at the starting time; S322: Statistical voltage difference A list of monomers g whose voltage difference is greater than a preset starting voltage difference threshold; S323: By formula The voltage difference between the ith monomer and monomer a at the end time is calculated; where, Indicates the voltage value corresponding to the i-th monomer at the end time; S324: Statistical voltage difference List h of cells whose voltage difference is greater than the preset end voltage difference threshold; let the union of lists g and h be list f of cells to be balanced; Determine whether the list to be balanced f is empty; if so, output the label that the monomer consistency does not need to be balanced; if not, mark it as completing the initial screening of the balanced monomer list.

6. The method for estimating full-time balanced capacity in the cloud based on cell voltage according to claim 1, characterized in that: The step of obtaining a list of starting time pairs for charging voltage curve shifting includes: S410: marking the cell with the lowest voltage at the end of charging as cell b; S411: Retrieve the list of balanced monomers after the initial screening and traverse the list to be balanced, mark the monomer that needs to be calculated currently as monomer k, and use the charging voltage curve of monomer k as the reference charging voltage curve; mark the starting time of the reference charging voltage curve segment selected by monomer k as s_k; and use the function Calculate the starting time of the fragment with the maximum similarity corresponding to monomer b, where: represents the Manhattan distance between the monomer b corresponding to the set time 1 and the monomer k corresponding to the set time 2, l_k represents the length of the reference charging voltage curve segment selected by the monomer k; S412: Mark the starting time pair of the reference charging voltage curve shift as (s_k, s_b); obtain a starting time pair list through the starting time pair.

7. The method for estimating full-time balanced capacity in the cloud based on cell voltage according to claim 6, characterized in that: The method for obtaining the Manhattan distance includes: Manhattan distance How to obtain: ; In the formula, represents the length of the reference charging voltage curve segment k1, express The voltage of cell k at the moment, express The voltage of cell b at this moment, The count subscript represents the voltage sampling time corresponding to the reference curve segment k1.

8. The method for estimating full-time balanced capacity in the cloud based on cell voltage according to claim 6, characterized in that: The step of obtaining the balanced battery capacity of the single cell from the list based on the starting time includes: S420: Retrieve the starting time pair list, obtain the charging current value between the starting time pairs in the starting time pair list, and calculate the battery capacities of the two time pairs respectively according to the ampere-hour integration method; S421: taking the average value of the battery capacity of the two time points as the balanced battery capacity of the single cell; S422: repeat steps S410-412 and steps S420-S421 to calculate the balanced battery capacity of all cells to be balanced compared with cell b.

9. The method for estimating full-time balanced capacity in the cloud based on cell voltage according to claim 1, characterized in that: The determining of a balancing solution according to the balancing battery capacity and the balancing cell list includes: Construct the battery management system BMS execution restrictions, where the BMS execution restrictions include: the balanced battery capacity can only open half of all cells at most and the corresponding balanced cells cannot be adjacent; Based on the BMS execution limit, the balancing cells corresponding to the balancing battery capacity are sorted in descending order, the final balancing list is constructed and initialized to be empty, and all the sorted balancing cells are traversed in turn; Determine whether there is a monomer adjacent to the currently traversed monomer in the final balancing list; if yes, skip the currently traversed monomer; if no, add the currently traversed monomer to the final balancing list; until the number of balanced monomers is greater than the limit or the sorted balanced monomer list is traversed, output the final balanced monomer list and the corresponding balanced capacity as the balancing solution, and end the algorithm; The actual balancing operation is performed by the BMS according to the balancing scheme.

10. A cloud-based full-time balanced capacity estimation electronic device based on single cell voltage, characterized in that: include: A memory and a processor, wherein the memory stores executable instructions of the processor; wherein the processor is configured to execute the cloud-based full-time balanced capacity estimation method based on single-cell voltage as described in any one of claims 1-9 by executing the executable instructions.

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