Storage battery fault intelligent detection method and system

Abstract

The invention relates to the technical field of electrical variable measurement, in particular to a storage battery fault intelligent detection method and system, and the method comprises the steps: determining the aging degree of a single battery through the charging and discharging cycle index, capacity data and environment temperature data of the single battery in a storage battery pack; correcting the current voltage value of the single battery by using the terminal voltage data, the capacity data and the aging degree of the single battery; correcting the capacity value by using the capacity data of the single battery and the environment temperature data; determining a voltage deviation degree and a capacity deviation degree between the corrected voltage value and the corrected capacity value and a corresponding average voltage and a corresponding average capacity in a series circuit where the single batteries are located; and determining a fault abnormity degree of the single battery by using the voltage deviation degree and the capacity deviation degree, and determining a fault battery by using the fault abnormity degree. By means of the intelligent storage battery fault detection method, the accuracy of storage battery anomaly detection is improved, and the storage battery with the fault anomaly can be located more accurately.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring electrical variables, and in particular to a battery fault intelligent detection method and system. Background Art

[0002] In the photovoltaic system, the battery is an important energy storage device. Its working environment is the worst and its failure rate is relatively high. Therefore, the battery is not only an important device of the photovoltaic system, but also the weakest link. The battery in the photovoltaic system is generally a battery pack composed of multiple single batteries connected in series and parallel. This battery system running on a battery pack can better store and convert electrical energy.

[0003] The battery is a key energy storage device in the photovoltaic system. With the use of the battery, the geometric structure of the battery plate will inevitably change gradually. The aggregate structure of its active material will gradually decay during the charging and discharging process. The physical structure and electrolyte density of each single battery will be different, resulting in inconsistency in the battery capacity and terminal voltage, which will cause unbalanced faults between batteries and cause the photovoltaic system to not operate normally. For example, the series battery pack is not charged enough, resulting in the system not being able to supply power normally, or the parallel battery pack charging current is not equal, the high-voltage battery pack is not charged enough, and the low-voltage battery pack is overcharged, which accelerates the damage of the two groups of batteries. Therefore, it is necessary to detect the unbalanced faults between batteries. However, the current battery fault detection technology is difficult to accurately locate the abnormal single battery, so as to replace it and protect the normal operation of the entire energy storage and photovoltaic system. Summary of the invention

[0004] In order to solve the technical problem of how to accurately locate a single battery with abnormal fault in a battery pack, the purpose of the present invention is to provide a battery fault intelligent detection method and system, and the technical solution adopted is as follows: The present invention provides a battery fault intelligent detection method, the method comprising: Determine the aging degree of a single cell by using the charge and discharge cycle number, capacity data and ambient temperature data of the single cell in the battery pack; Using the terminal voltage data, capacity data and aging degree of the single battery, the current voltage value of the single battery is corrected to obtain the current corrected voltage value; Using the capacity data and ambient temperature data of the single battery, the reference capacity value corresponding to the current voltage value in the associated reference data is corrected to obtain the current corrected capacity value; Determine the voltage deviation degree and capacity deviation degree between the current corrected voltage value and the current corrected capacity value and the corresponding average voltage and average capacity in the series circuit where the single battery is located; The voltage deviation degree and the capacity deviation degree are used to determine the abnormality degree of the single battery failure, and the abnormality degree of the failure is used to determine the faulty battery.

[0005] Furthermore, the step of determining the aging degree of a single cell by using the charge and discharge cycle number, capacity data and ambient temperature data of the single cell in the battery pack includes: Determine the capacity attenuation coefficient of a single battery by using the capacity value difference between adjacent charge and discharge cycles of a single battery in a battery pack under the same charging condition and / or the same discharging condition; The aging degree of the single battery is determined by using the capacity attenuation coefficient, the number of charge and discharge cycles, and the difference between the real-time temperature value of the environment where the single battery is located and the standard ambient temperature.

[0006] Furthermore, the step of determining the capacity attenuation coefficient of a single battery by using the difference in capacity values ​​between adjacent charge and discharge cycles of the single battery in the battery pack under the same charging condition and / or the same discharging condition comprises: Determine a difference in first capacity values ​​between adjacent charge and discharge cycles of the single battery after a preset discharge time; Determine the difference in second capacity values ​​between adjacent charge and discharge cycles of the single battery when both are fully charged; Determine the variance of the absolute difference between all lower capacity measurement values ​​of the single battery and a preset lower capacity standard value; The capacity attenuation coefficient of the single battery is calculated using the first capacity value difference, the second capacity value difference, and the variance of the absolute difference.

[0007] Furthermore, the step of correcting the current voltage value of the single battery to obtain the current corrected voltage value by using the terminal voltage data, capacity data and aging degree of the single battery includes: The overall instability of the terminal voltage of a single cell is determined by using the terminal voltage difference of the single cell corresponding to the same data sequence between any two different charge and discharge cycles; determining an inverse normalized value of the Pearson correlation coefficient between the terminal voltage data and the capacity data; The current voltage value of the single battery is corrected by using the overall instability, the inverse normalized value and the aging degree to obtain the current corrected voltage value.

[0008] Furthermore, the step of determining the overall instability of the terminal voltage of the single cell by using the terminal voltage difference of the single cell corresponding to the same data sequence between any two different charge and discharge cycles includes: Determine the instability of the terminal voltage of the single cell for the two different charge and discharge cycles by using the terminal voltage difference of the single cell corresponding to the same data sequence between any two different charge and discharge cycles and the number of terminal voltages within any charge and discharge cycle; The overall instability degree of the terminal voltage of the single cell is calculated using each instability degree and the number of cycles of all charge and discharge cycles.

[0009] Further, the step of using the capacity data and the ambient temperature data of the single battery to correct the reference capacity value corresponding to the current voltage value in the associated reference data to obtain the current corrected capacity value includes: Determine the temperature difference between the ambient temperature value corresponding to the last capacity measurement value in the capacity data and the standard ambient temperature; The reference capacity value corresponding to the current voltage value in the associated reference data is corrected by using the preset capacity environment coefficient and the temperature difference to obtain the current corrected capacity value.

[0010] Furthermore, the average voltage includes the average value of the current corrected voltage values ​​of all batteries in the series circuit where the single battery is located; the average capacitance includes the average value of the current corrected capacitance values ​​of all batteries in the series circuit where the single battery is located; The steps of determining the abnormality degree of the single battery fault by using the voltage deviation degree and the capacity deviation degree include: The fault abnormality degree of the single battery is calculated using the voltage deviation degree, the capacity deviation degree and the preset capacity control error.

[0011] Furthermore, before the step of determining the abnormality degree of the single battery failure by using the voltage deviation degree and the capacity deviation degree, the method further includes: Determine the absolute current difference between the first branch current and the second branch current in the two parallel paths where the battery pack is located; Comparing the absolute current difference with a preset current change threshold to determine whether the battery pack is an abnormal battery pack; When the storage battery group is determined to be an abnormal storage battery group, a step of determining the degree of abnormal failure of the single battery using the degree of voltage deviation and the degree of capacity deviation is performed.

[0012] Furthermore, the step of determining the faulty battery using the fault abnormality degree includes: Compare the fault abnormality degree with the preset abnormality threshold to determine whether the single battery is a faulty battery.

[0013] The present invention also provides a battery fault intelligent detection system, the system is used to implement the battery fault intelligent detection method as described in any one of the above items; the system comprises: An aging monitoring module is used to determine the aging degree of a single cell in a battery pack by using the charge and discharge cycle number, capacity data, and ambient temperature data of the single cell; The voltage correction module is used to correct the current voltage value of the single battery by using the terminal voltage data, capacity data and aging degree of the single battery to obtain the current corrected voltage value; The capacity correction module is used to correct the reference capacity value corresponding to the current voltage value in the associated reference data by using the capacity data of the single battery and the ambient temperature data to obtain the current corrected capacity value; A deviation calculation module, used to determine the voltage deviation degree and capacity deviation degree between the current corrected voltage value and the current corrected capacity value and the corresponding average voltage and average capacity in the series circuit where the single battery is located; The fault location module is used to determine the fault abnormality degree of the single battery by using the voltage deviation degree and the capacity deviation degree, and to determine the faulty battery by using the fault abnormality degree.

[0014] The present invention has the following beneficial effects: The present invention determines the aging degree of the battery by comprehensively analyzing the number of charge and discharge cycles of the battery, the change in capacity data and the change in ambient temperature data, and obtains a correction value of the battery terminal voltage according to the fluctuation of the battery (terminal) voltage data, its similarity with the capacity curve and the aging degree, thereby reducing the influence of the battery aging and the severity of the ambient temperature on the relevant electrical parameters, and then obtains the correction value of the battery capacity according to the capacity data, the ambient temperature data and the reference capacity value corresponding to the current voltage value, and fully analyzes the battery failure anomaly analysis of the battery in the photovoltaic system under the corresponding circuit connection mode, thereby improving the accuracy of the detection of imbalance and anomaly between batteries, and then being able to more accurately locate the battery with a fault anomaly, thereby replacing the abnormal battery and realizing the normal operation of the energy storage system and the photovoltaic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A flowchart of a method for intelligently detecting battery failures provided by one embodiment of the present invention; Figure 2 A detailed flow chart of step S1 in a battery fault intelligent detection method provided by one embodiment of the present invention; Figure 3 A detailed flow chart of step S2 in a battery fault intelligent detection method provided by one embodiment of the present invention; Figure 4A detailed flow chart of step S3 in a battery fault intelligent detection method provided by one embodiment of the present invention; Figure 5 A schematic diagram of the structure of the hardware operating environment of the battery fault intelligent detection device involved in the embodiment of the present invention; Figure 6 The figure is a schematic diagram of the framework structure of the battery fault intelligent detection system involved in the embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of a battery fault intelligent detection method proposed by the present invention, its specific implementation, structure, features and effects, in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0018] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0019] A specific scheme of a battery fault intelligent detection method provided by the present invention is described in detail below with reference to the accompanying drawings.

[0020] Embodiment 1: For a battery fault intelligent detection method provided by the present invention, please refer to Figure 1 , which shows a flowchart of the steps of a battery fault intelligent detection method provided by an embodiment of the present invention.

[0021] The method comprises: Step S1, using the charge and discharge cycle number, capacity data and ambient temperature data of the single battery in the battery pack to determine the aging degree of the single battery; A battery pack is generally formed by connecting multiple batteries in series.

[0022] The capacity data of each battery in the battery pack at historical time is obtained, and the capacity curve can be generated; the terminal voltage data of each battery in the battery pack is obtained, and the terminal voltage curve can be generated; the associated reference data of the battery capacity and terminal voltage is obtained, and the reference curve can be generated; the number of charge and discharge cycles of each battery in the battery pack is obtained; the temperature data of the environment where the battery is located and the standard ambient temperature are obtained.

[0023] It should be noted that, in the battery pack in the scenario of this embodiment, each battery has a separate electronic control unit that can monitor relevant information of the battery.

[0024] The capacity curve can be a curve formed by the capacity values ​​of the last 10 working cycles obtained by the battery capacity tester. A complete charge and discharge cycle is a working cycle, so the working cycle can also be called the charge and discharge cycle. The specific working cycle can be adjusted according to actual needs. The terminal voltage curve of the battery can also be the terminal voltage of the last 10 working cycles, which is specifically obtained by a voltmeter, and the current value can be obtained by an ammeter. The reference curve of the battery capacity and terminal voltage is a reference curve of the capacity and terminal voltage obtained by measuring a normal battery at a standard ambient temperature using a battery capacity tester and a voltmeter. Each terminal voltage corresponds to a unique capacity value, which can be reflected in the coordinate system by setting different capacity values ​​on the horizontal axis and voltage values ​​corresponding to different capacity values ​​on the vertical axis. The temperature data of the environment where the battery is located can be a temperature sequence consisting of the ambient temperature values ​​corresponding to the time unit of 10 working cycles in days. The standard ambient temperature can be set to 25 degrees Celsius, which can be adjusted as needed.

[0025] For details, please refer to Figure 2 , step S1, comprising: Step S11, determining the capacity attenuation coefficient of a single battery by using the capacity value difference between adjacent charge and discharge cycles of a single battery in the battery pack under the same charging condition and / or the same discharging condition; More specifically, step S11 includes: Determine a difference in first capacity values ​​between adjacent charge and discharge cycles of the single battery after a preset discharge time; Determine the difference in second capacity values ​​between adjacent charge and discharge cycles of the single battery when both are fully charged; Determine the variance of the absolute difference between all lower capacity measurement values ​​of the single battery and a preset lower capacity standard value; The capacity attenuation coefficient of the single battery is calculated using the first capacity value difference, the second capacity value difference, and the variance of the absolute difference.

[0026] Step S12, determining the aging degree of the single battery by using the capacity attenuation coefficient, the number of charge and discharge cycles, and the difference between the real-time temperature value of the environment where the single battery is located and the standard ambient temperature.

[0027] Since the capacity of the battery will gradually decrease during actual use, as the number of charge and discharge cycles increases, the battery capacity will decay significantly, that is, aging will occur, and changes in ambient temperature will accelerate aging. Long-term operation in a high temperature environment will cause more serious aging than aging at normal temperatures. In order to better analyze lagging batteries (faulty and abnormal batteries), it is necessary to analyze the aging degree of the battery.

[0028] All maximum capacity values ​​and minimum capacity values ​​in the capacity curve of the i-th battery in the battery pack are obtained, and the capacity curve between adjacent maximum capacity values ​​and minimum capacity values ​​is used as a working cycle of the i-th battery.

[0029]

[0030] In the above formula, is the average value of the differences (first capacity value differences) of all adjacent capacity values ​​after the preset discharge time in all working cycles of the capacity curve of the i-th battery in the battery pack, where adjacent may be right adjacent, and the preset time in this embodiment may be 10 minutes, which may be adjusted; is the number of all maximum capacity values ​​in the capacity curve of the i-th battery in the battery pack, is the absolute difference between the ath maximum capacity value and the a+1th maximum capacity value in the capacity curve of the i-th battery in the battery pack (second capacity value difference), is the variance of the absolute difference between all the minimum capacity values ​​(lower capacity measurement values) in the capacity curve of the ith battery in the battery pack and the preset lower capacity standard value, where the preset capacity value can be 20%. is the capacity attenuation coefficient of the ith battery in the battery pack.

[0031] The logic of the above formula is: It indicates the difference in capacity values ​​between adjacent working cycles after a period of discharge. If the battery does not experience capacity decay, the capacity will be basically the same after working for a period of time in each working cycle. If aging causes capacity decay, the amount of electricity that can be stored in the battery will decrease, and the capacity will change after working for a period of time. The larger it is, the more likely it is that there is capacity attenuation; Indicates the capacity difference of the battery when it is fully charged in adjacent working cycles. The larger the value, the more serious the capacity decay; Indicates the difference between the lower limit capacity measurement value and the set standard lower limit capacity. The larger the value is, the more serious the capacity decay is, indicating that the battery is over-discharged due to capacity decay.

[0032]

[0033] In the above formula, is the number of charge and discharge cycles of the ith battery in the battery pack; is a linear normalization function used for normalization. is the aging degree of the i-th battery in the battery pack, It is the average value of the absolute difference between each temperature value (which can be a real-time temperature value in days) in the temperature data of the environment where the i-th battery is located and the standard ambient temperature.

[0034] The logic of the above formula is: the greater the number of charge and discharge cycles of the battery, the greater the battery capacity attenuation coefficient and temperature change compared to the standard ambient temperature, which means that the degree of battery aging is more serious. With repeated cycles of charge and discharge, this difference continues to increase, gradually forming the so-called lagging battery, that is, a faulty abnormal battery.

[0035] Step S2, using the terminal voltage data, capacity data and aging degree of the single battery, correcting the current voltage value of the single battery to obtain a current corrected voltage value; For details, please refer to Figure 3 , step S2, comprising: Step S21, using the terminal voltage difference of the single battery corresponding to the same data sequence between any two different charge and discharge cycles to determine the overall instability of the single battery terminal voltage; More specifically, step S21 includes: Determine the instability of the terminal voltage of the single cell for the two different charge and discharge cycles by using the terminal voltage difference of the single cell corresponding to the same data sequence between any two different charge and discharge cycles and the number of terminal voltages within any charge and discharge cycle; The overall instability degree of the terminal voltage of the single cell is calculated using each instability degree and the number of cycles of all charge and discharge cycles.

[0036] Step S22, determining an inverse normalized value of a Pearson correlation coefficient between the terminal voltage data and the capacity data; Step S23, using the overall instability, the inverse normalized value and the aging degree, correcting the current voltage value of the single battery to obtain a current corrected voltage value.

[0037] As the battery ages, the energy stored and released through chemical reactions inside the battery will decrease due to the gradual loss of active substances inside the battery. The number of active substances that can participate in the reaction will decrease, causing the terminal voltage of the battery to drop too quickly during discharge, and the terminal voltage curve will tend to be unstable. If the impact of the terminal voltage on the degree of aging is not analyzed, errors will occur when the battery is subsequently analyzed based on the terminal voltage. Ideally, the relevant electrical parameters can be determined based on the reference curve of capacity and terminal voltage. Knowing the voltage can determine the capacity, and knowing the capacity can determine the voltage. At the same time, the more unstable the battery aging degree and the terminal voltage curve are, the more serious the damage to the battery aging is, and the more the current voltage value should be increased.

[0038] The terminal voltage curve segment corresponding to the terminal voltage curve of the i-th battery in each working cycle of the i-th battery in the battery pack is taken as the terminal voltage working cycle of the i-th battery. Since the capacity and terminal voltage of the battery are relatively close, the lower the capacity of the battery, the lower its terminal voltage. The above analysis is based on capacitance to analyze a working cycle of the battery. Here, the working cycle is corresponded in the terminal voltage curve, and the change of terminal voltage under the same working cycle is analyzed to determine the corrected voltage value, so as to more accurately judge the lagging battery. For example, the working cycle is from the 5th second to the 10th second, and the voltage curve segment from the 5th second to the 10th second is obtained in the terminal voltage curve as a terminal voltage working cycle.

[0039]

[0040] In the above formula, is the number of terminal voltages in any terminal voltage working cycle in the terminal voltage curve of the ith battery in the battery pack, is the cth voltage value in the bth terminal voltage working cycle in the terminal voltage curve of the ith battery in the battery pack, is the terminal voltage curve of the ith battery in the battery pack The cth voltage value in the working cycle of the terminal voltage, is the voltage duty cycle of the bth terminal of the ith battery in the battery pack and the The instability of the terminal voltage during the working cycle of the terminal voltage.

[0041] Formula logic: It represents the difference in terminal voltages of the ith battery in the battery pack in the corresponding data order within any two different terminal voltage working cycles. The greater the difference in terminal voltages of the corresponding data order, that is, the terminal voltages are different when the capacities are similar under the same discharge conditions, the more unstable the terminal voltage curve is, and the more seriously the terminal voltage of the battery is affected by aging.

[0042]

[0043] In the above formula, is the number of all terminal voltage working cycles in the terminal voltage curve of the ith battery in the battery pack, is the overall instability of the terminal voltage curve of the i-th battery in the battery pack.

[0044]

[0045] In the above formula, is the inverse normalized value of the Pearson correlation coefficient between the terminal voltage curve and the capacity curve of the ith battery in the battery pack. Specifically, the inverse normalization is performed through the function of exp(-x), where x represents the input. is the aging degree of the i-th battery in the battery pack; is the current corrected voltage value of the i-th battery in the battery pack, is the current voltage value of the ith battery in the battery pack, where the current voltage value is the last voltage value in the terminal voltage curve of the ith battery.

[0046] Formula logic: When the Pearson correlation coefficient between the terminal voltage curve and the capacity curve of the ith battery in the battery pack is smaller, it means that the aging effect has destroyed the relationship between the terminal voltage curve and the capacity curve. Ideally, the relevant electrical parameters can be determined based on the reference curve of capacity and terminal voltage. Knowing the voltage can determine the capacity, and knowing the capacity can determine the voltage. At the same time, if the battery aging degree and the terminal voltage curve are more unstable, the battery aging damage is more serious, and the current voltage value should be increased. Therefore, through To correct the current voltage value, obtain the current corrected voltage value of the i-th battery in the battery pack.

[0047] Step S3, using the capacity data of the single battery and the ambient temperature data, correcting the reference capacity value corresponding to the current voltage value in the associated reference data to obtain a current corrected capacity value; For details, please refer to Figure 4 , step S3, comprising: Step S31, determining the temperature difference between the ambient temperature value corresponding to the last capacity measurement value in the capacity data and the standard ambient temperature; Step S32, using the preset capacity environment coefficient and the temperature difference, correcting the reference capacity value corresponding to the current voltage value in the associated reference data to obtain the current corrected capacity value.

[0048] Under different ambient temperatures, the actual capacity of the battery will change to a certain extent. Under low temperature environment, the actual capacity of the battery will decrease; under high temperature environment, the capacity will increase. If the end capacity is affected by the harsh environment without analysis, it will cause errors in the subsequent analysis of the backward battery. Therefore, the current capacity is corrected according to the capacity at the reference temperature and the change of ambient temperature to obtain the corrected value of the battery capacity.

[0049]

[0050] In the above formula, is the reference capacity value corresponding to the current voltage value of the ith battery in the battery pack in the reference curve of capacity and terminal voltage, The preset capacity temperature coefficient is used to reflect the impact of the capacity on the harsh environment. .01 to describe, Indicates the ambient temperature value when the last capacity value (the last capacity measurement value) is measured in the capacity curve of the i-th battery in the battery pack. It is the ambient temperature value corresponding to the reference curve of capacity and terminal voltage, that is, the standard ambient temperature; is the current corrected capacity value of the i-th battery in the battery pack.

[0051] Formula logic: Ideally, the corresponding relationship between voltage and capacity can be determined based on the reference curve of capacity and terminal voltage. However, due to battery aging and the influence of harsh environment, the capacity value will change to a certain extent and is not the ideal capacity value. By analyzing the difference between the actual temperature and the standard ambient temperature, the initial reference capacity value is corrected. The smaller the temperature difference, the smaller the impact on the battery, and the less correction is made. Finally, the current corrected capacity value of the i-th battery in the battery pack is obtained.

[0052] Step S4, determining the voltage deviation degree and capacity deviation degree between the current corrected voltage value and the current corrected capacity value and the corresponding average voltage and average capacity in the series circuit where the single battery is located; The average voltage includes the average value of the current corrected voltage values ​​of all batteries in the series circuit where the single battery is located; the average capacitance includes the average value of the current corrected capacitance values ​​of all batteries in the series circuit where the single battery is located.

[0053] By detecting the corrected voltage and corrected capacity value of each battery in the series battery pack, the degree to which a single battery deviates from the average level is determined. The greater the deviation, the more backward the battery.

[0054] Step S5, determining the abnormality degree of the single battery fault using the voltage deviation degree and the capacity deviation degree, and determining the faulty battery using the abnormality degree of the fault.

[0055] Specifically, the step of determining the abnormality degree of the single battery fault by using the voltage deviation degree and the capacity deviation degree includes: The fault abnormality degree of the single battery is calculated using the voltage deviation degree, the capacity deviation degree and the preset capacity control error.

[0056] Battery packs are generally connected in series and in parallel. These two connection methods can effectively meet different voltage and capacity requirements, thereby improving the energy storage capacity of the battery pack. The main function of the series connection is to increase the total voltage of the battery pack, and the main function of the parallel connection is to increase the total capacity of the battery pack. The capacity of each battery (in ampere-hours (Ah)) is its ability to store electrical energy. The capacity of a single battery is fixed, but by connecting multiple batteries in parallel, the total capacity of the battery pack is equal to the sum of the capacities of all batteries. If there is a lagging battery in the series battery pack, the back electromotive force of this battery will increase, causing the voltage of the battery to increase, which will in turn increase the voltage of the entire battery pack, resulting in insufficient charging of the entire battery pack. Therefore, it is necessary to analyze the degree of abnormality of each battery in the series battery pack.

[0057] Assume that the i-th battery in the battery pack is a battery in a series branch.

[0058]

[0059] In the above formula, is the current corrected voltage value of the i-th battery in the battery pack, is the average value of the current corrected voltage values ​​of all batteries in the series branch where the i-th battery in the battery pack is located, is the current corrected capacity value of the i-th battery in the battery pack, is the average value of the current corrected capacity of all batteries in the series branch where the i-th battery in the battery pack is located, is the preset capacity control error value, , can be adjusted as needed; is the fault abnormality degree of the i-th battery in the battery pack.

[0060] Formula logic: The current of each battery in the series branch is equal. If there is a voltage value in the series branch that deviates from the average level, the more the deviation, the more abnormal it is. At the same time, analyze whether the capacitance has obvious deviations. Since the lower limit of reasonable battery use is generally to retain 20% residual capacity to avoid deep discharge of some batteries, if the capacity of a battery deviates too much from the average level, that is, exceeds the capacity control error value, the larger the value, the more abnormal it is.

[0061] The steps of determining the faulty battery using the fault abnormality degree include: Compare the fault abnormality degree with the preset abnormality threshold to determine whether the single battery is a faulty battery.

[0062] The greater the fault abnormality, the more likely it is a lagging battery, that is, a battery with a possible fault abnormality. The preset abnormality threshold can be set to 0.8, and the preset abnormality threshold can be adjusted as needed. The above fault abnormality degree is normalized and compared with the preset abnormality threshold. If it is greater than or equal to the abnormality threshold, the battery is regarded as a lagging battery, otherwise, it is regarded as a normal battery.

[0063] After detecting lagging batteries, the staff can promptly replace them with spare batteries to ensure the normal operation of the system.

[0064] In one embodiment, before step S5, the method further includes: Determine the absolute current difference between the first branch current and the second branch current in the two parallel paths where the battery pack is located; Comparing the absolute current difference with a preset current change threshold to determine whether the battery pack is an abnormal battery pack; When the storage battery group is determined to be an abnormal storage battery group, a step of determining the degree of abnormal failure of the single battery using the degree of voltage deviation and the degree of capacity deviation is performed.

[0065] In a parallel battery pack, ideally the currents of the two parallel paths are the same, and the two battery packs can work normally. However, due to battery imbalance, the currents of the two battery packs are often not equal in actual operation, and the more single cells in the battery pack are connected in series, the greater the difference in current. When charging at a constant voltage, the two battery groups are charged to different degrees, the high-voltage battery group is undercharged, and the low-voltage battery group is overcharged.

[0066] Assume that battery group A and battery group B are operated in parallel, the current of the branch where battery group A is located is (current of the first branch), the current of the branch where battery group B is located is (Second branch current), + is the total current .

[0067] Get the current of the two parallel paths respectively, and record them as and , get and The absolute difference of the current change threshold is preset to 0.3, which can be adjusted according to the actual situation. and If the absolute difference is greater than the preset current change threshold, it means that there is an abnormal battery in the battery pack in the two parallel paths. Then, the above steps of obtaining the abnormal degree of the fault are used to analyze the abnormal degree of the two parallel paths respectively to determine which branch has the abnormal battery. The specific process will not be repeated here, and the two parallel paths can be regarded as two series circuits for analysis.

[0068] Formula logic: When and The larger the absolute difference, the more unbalanced the two parallel paths are. Ideally, the currents of the two parallel paths are equal. If there is a large difference, it means that there is a lagging battery. Therefore, the two parallel paths are analyzed based on the abnormality of the above analysis.

[0069] The present invention determines the aging degree of the battery by comprehensively analyzing the number of charge and discharge cycles of the battery, the change in capacity data and the change in ambient temperature data, and obtains a correction value of the battery terminal voltage according to the fluctuation of the battery (terminal) voltage data, its similarity with the capacity curve and the aging degree, thereby reducing the influence of the battery aging and the severity of the ambient temperature on the relevant electrical parameters, and then obtains the correction value of the battery capacity according to the capacity data, the ambient temperature data and the reference capacity value corresponding to the current voltage value, and fully analyzes the battery failure anomaly analysis of the battery in the photovoltaic system under the corresponding circuit connection mode, thereby improving the accuracy of the detection of imbalance and anomaly between batteries, and then being able to more accurately locate the battery with a fault anomaly, thereby replacing the abnormal battery and realizing the normal operation of the energy storage system and the photovoltaic system.

[0070] Embodiment 2: The embodiment of the present invention also provides a battery fault intelligent detection device. The battery fault intelligent detection device can be a data calculation and processing device such as a computer, a server, or a combination of multiple devices.

[0071] like Figure 5 As shown, Figure 5 It is a structural diagram of the hardware operating environment of the battery fault intelligent detection device involved in the embodiment of the present invention.

[0072] like Figure 5As shown, the battery fault intelligent detection device may include: a processor 1001, such as a CPU, a network interface 1004, a user interface 1003, a memory 1005, and a communication bus 1002. Among them, the communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display (Display), an input unit such as a control panel, and the optional user interface 1003 may also include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a WIFI interface). The memory 1005 may be a high-speed RAM memory or a stable memory (non-volatile memory), such as a disk memory. The memory 1005 may also be a storage device independent of the aforementioned processor 1001. The memory 1005 as a computer storage medium may include a battery fault intelligent detection program.

[0073] Those skilled in the art will understand that Figure 5 The hardware structure shown in the figure does not constitute a limitation of the device, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.

[0074] Continue to refer to Figure 5 , Figure 5 The memory 1005 as a computer-readable storage medium may include an operating system, a user interface module, a network communication module, and a battery fault intelligent detection program.

[0075] exist Figure 5 In the embodiment, the network communication module is mainly used to connect to the server and can communicate data with the server; and the processor 1001 can call the battery fault intelligent detection program stored in the memory 1005 and execute the steps in the above embodiments.

[0076] The hardware structure of the above-mentioned battery fault intelligent detection device is used to implement various embodiments of the battery fault intelligent detection method of the present invention.

[0077] In addition, the present invention also provides a battery fault intelligent detection system, please refer to Figure 6 , the battery fault intelligent detection system comprises: The aging monitoring module A10 is used to determine the aging degree of the single battery by using the charge and discharge cycle number, capacity data and ambient temperature data of the single battery in the battery pack; The voltage correction module A20 is used to correct the current voltage value of the single battery by using the terminal voltage data, capacity data and aging degree of the single battery to obtain a current corrected voltage value; The capacity correction module A30 is used to correct the reference capacity value corresponding to the current voltage value in the associated reference data using the capacity data of the single battery and the ambient temperature data to obtain the current corrected capacity value; The deviation calculation module A40 is used to determine the voltage deviation degree and the capacity deviation degree between the current corrected voltage value and the current corrected capacity value and the corresponding average voltage and average capacity in the series circuit where the single battery is located; The fault location module A50 is used to determine the fault abnormality degree of the single battery by using the voltage deviation degree and the capacity deviation degree, and to determine the faulty battery by using the fault abnormality degree.

[0078] Furthermore, the aging monitoring module A10 is also used for: Determine the capacity attenuation coefficient of a single battery by using the capacity value difference between adjacent charge and discharge cycles of a single battery in a battery pack under the same charging condition and / or the same discharging condition; The aging degree of the single battery is determined by using the capacity attenuation coefficient, the number of charge and discharge cycles, and the difference between the real-time temperature value of the environment where the single battery is located and the standard ambient temperature.

[0079] Furthermore, the aging monitoring module A10 is also used for: Determine a difference in first capacity values ​​between adjacent charge and discharge cycles of the single battery after a preset discharge time; Determine the difference in second capacity values ​​between adjacent charge and discharge cycles of the single battery when both are fully charged; Determine the variance of the absolute difference between all lower capacity measurement values ​​of the single battery and a preset lower capacity standard value; The capacity attenuation coefficient of the single battery is calculated using the first capacity value difference, the second capacity value difference, and the variance of the absolute difference.

[0080] Furthermore, the voltage correction module A20 is also used for: The overall instability of the terminal voltage of a single cell is determined by using the terminal voltage difference of the single cell corresponding to the same data sequence between any two different charge and discharge cycles; determining an inverse normalized value of the Pearson correlation coefficient between the terminal voltage data and the capacity data; The current voltage value of the single battery is corrected by using the overall instability, the inverse normalized value and the aging degree to obtain the current corrected voltage value.

[0081] Furthermore, the voltage correction module A20 is also used for: Determine the instability of the terminal voltage of the single cell for the two different charge and discharge cycles by using the terminal voltage difference of the single cell corresponding to the same data sequence between any two different charge and discharge cycles and the number of terminal voltages within any charge and discharge cycle; The overall instability degree of the terminal voltage of the single cell is calculated using each instability degree and the number of cycles of all charge and discharge cycles.

[0082] Furthermore, the capacity correction module A30 is also used for: Determine the temperature difference between the ambient temperature value corresponding to the last capacity measurement value in the capacity data and the standard ambient temperature; The reference capacity value corresponding to the current voltage value in the associated reference data is corrected by using the preset capacity environment coefficient and the temperature difference to obtain the current corrected capacity value.

[0083] Furthermore, the fault location module A50 is also used for: The fault abnormality degree of the single battery is calculated using the voltage deviation degree, the capacity deviation degree and the preset capacity control error.

[0084] Furthermore, the fault location module A50 is also used for: Determine the first branch current and the second branch current in the two parallel paths where the battery pack is located, and the absolute current difference between the two branch currents; Comparing the absolute current difference with a preset current change threshold to determine whether the battery pack is an abnormal battery pack; When the storage battery group is determined to be an abnormal storage battery group, a step of determining the degree of abnormal failure of the single battery using the degree of voltage deviation and the degree of capacity deviation is performed.

[0085] Furthermore, the fault location module A50 is also used for: Compare the fault abnormality degree with the preset abnormality threshold to determine whether the single battery is a faulty battery.

[0086] The specific implementation of the battery fault intelligent detection system of the present invention is basically the same as the embodiments of the above-mentioned battery fault intelligent detection method, and will not be repeated here.

[0087] In addition, the present invention also provides a computer-readable storage medium. The computer-readable storage medium of the present invention stores a battery fault intelligent detection program, wherein when the battery fault intelligent detection program is executed by a processor, the steps of the battery fault intelligent detection method described above are implemented.

[0088] Among them, the method implemented when the battery fault intelligent detection program is executed can refer to the various embodiments of the battery fault intelligent detection method of the present invention, and will not be repeated here.

[0089] It should be noted that the sequence of the above embodiments of the present invention is for description only and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0090] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0091] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0092] The above description is only a preferred embodiment of the present invention, and does not limit the protection scope of the present invention. All equivalent structural / method transformations made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the protection scope of the present invention.

Claims

1. A battery fault intelligent detection method, characterized in that: The method comprises: Determine the aging degree of a single cell by using the charge and discharge cycle number, capacity data and ambient temperature data of the single cell in the battery pack; Using the terminal voltage data, capacity data and aging degree of the single battery, the current voltage value of the single battery is corrected to obtain the current corrected voltage value; Using the capacity data and ambient temperature data of the single battery, the reference capacity value corresponding to the current voltage value in the associated reference data is corrected to obtain the current corrected capacity value; Determine the voltage deviation degree and capacity deviation degree between the current corrected voltage value and the current corrected capacity value and the corresponding average voltage and average capacity in the series circuit where the single battery is located; Determine the fault abnormality degree of the single battery using the voltage deviation degree and the capacity deviation degree, and determine the faulty battery using the fault abnormality degree; The associated reference data is obtained by testing the capacity and terminal voltage at standard ambient temperature.

2. The battery failure intelligent detection method according to claim 1, characterized in that: The steps of determining the aging degree of a single battery in a battery pack by using the charge and discharge cycle number, capacity data and ambient temperature data of the single battery in the battery pack include: Determine the capacity attenuation coefficient of a single battery by using the capacity value difference between adjacent charge and discharge cycles of a single battery in a battery pack under the same charging condition and / or the same discharging condition; The aging degree of the single battery is determined by using the capacity attenuation coefficient, the number of charge and discharge cycles, and the difference between the real-time temperature value of the environment where the single battery is located and the standard ambient temperature.

3. The battery failure intelligent detection method according to claim 2 is characterized in that: The step of determining the capacity attenuation coefficient of a single battery by using the difference in capacity values ​​between adjacent charge and discharge cycles of a single battery in a battery pack under the same charging condition and / or the same discharging condition comprises: Determine a difference in first capacity values ​​between adjacent charge and discharge cycles of the single battery after a preset discharge time; Determine the difference in second capacity values ​​between adjacent charge and discharge cycles of the single battery when both are fully charged; Determine the variance of the absolute difference between all lower capacity measurement values ​​of the single battery and a preset lower capacity standard value; The capacity attenuation coefficient of the single battery is calculated using the first capacity value difference, the second capacity value difference, and the variance of the absolute difference.

4. The battery failure intelligent detection method according to claim 1, characterized in that: The steps of correcting the current voltage value of the single battery to obtain the current corrected voltage value by using the terminal voltage data, capacity data and aging degree of the single battery include: The overall instability of the terminal voltage of a single cell is determined by using the terminal voltage difference of the single cell corresponding to the same data sequence between any two different charge and discharge cycles; determining an inverse normalized value of the Pearson correlation coefficient between the terminal voltage data and the capacity data; The current voltage value of the single battery is corrected by using the overall instability, the inverse normalized value and the aging degree to obtain the current corrected voltage value.

5. The battery fault intelligent detection method according to claim 4, characterized in that: The steps of determining the overall instability of the terminal voltage of the single battery by using the terminal voltage difference of the single battery corresponding to the same data sequence between any two different charge and discharge cycles include: Determine the instability of the terminal voltage of the single cell for the two different charge and discharge cycles by using the terminal voltage difference of the single cell corresponding to the same data sequence between any two different charge and discharge cycles and the number of terminal voltages within any charge and discharge cycle; The overall instability degree of the terminal voltage of the single cell is calculated using each instability degree and the number of cycles of all charge and discharge cycles.

6. The battery fault intelligent detection method according to claim 1, characterized in that: The step of correcting the reference capacity value corresponding to the current voltage value in the associated reference data by using the capacity data and the ambient temperature data of the single battery to obtain the current corrected capacity value includes: Determine the temperature difference between the ambient temperature value corresponding to the last capacity measurement value in the capacity data and the standard ambient temperature; The reference capacity value corresponding to the current voltage value in the associated reference data is corrected by using the preset capacity environment coefficient and the temperature difference to obtain the current corrected capacity value.

7. The battery fault intelligent detection method according to claim 1, characterized in that: The average voltage includes the average value of the current corrected voltage values ​​of all batteries in the series circuit where the single battery is located; the average capacitance includes the average value of the current corrected capacitance values ​​of all batteries in the series circuit where the single battery is located; The steps of determining the abnormality degree of the single battery fault by using the voltage deviation degree and the capacity deviation degree include: The fault abnormality degree of the single battery is calculated using the voltage deviation degree, the capacity deviation degree and the preset capacity control error.

8. The battery fault intelligent detection method according to claim 1, characterized in that: Before the step of determining the abnormality degree of the single battery failure by using the voltage deviation degree and the capacity deviation degree, the method further includes: Determine the absolute current difference between the first branch current and the second branch current in the two parallel paths where the battery pack is located; Comparing the absolute current difference with a preset current change threshold to determine whether the battery pack is an abnormal battery pack; When the storage battery group is determined to be an abnormal storage battery group, a step of determining the degree of abnormal failure of the single battery using the degree of voltage deviation and the degree of capacity deviation is performed.

9. The battery fault intelligent detection method according to claim 1, characterized in that: The steps of determining the faulty battery using the fault abnormality degree include: Compare the fault abnormality degree with the preset abnormality threshold to determine whether the single battery is a faulty battery.

10. A battery fault intelligent detection system, characterized in that: The system is used to implement the battery fault intelligent detection method according to any one of claims 1 to 9; the system comprises: An aging monitoring module is used to determine the aging degree of a single cell in a battery pack by using the charge and discharge cycle number, capacity data, and ambient temperature data of the single cell; The voltage correction module is used to correct the current voltage value of the single battery by using the terminal voltage data, capacity data and aging degree of the single battery to obtain the current corrected voltage value; The capacity correction module is used to correct the reference capacity value corresponding to the current voltage value in the associated reference data by using the capacity data of the single battery and the ambient temperature data to obtain the current corrected capacity value; A deviation calculation module, used to determine the voltage deviation degree and capacity deviation degree between the current corrected voltage value and the current corrected capacity value and the corresponding average voltage and average capacity in the series circuit where the single battery is located; The fault location module is used to determine the fault abnormality degree of the single battery by using the voltage deviation degree and the capacity deviation degree, and to determine the faulty battery by using the fault abnormality degree.

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