A SOH calibration method, device, equipment and medium

Abstract

The present application discloses a SOH calibration method, device, equipment and medium, which are applied to the energy storage field and include: monitoring the open-circuit voltage and current of the battery, when the open-circuit voltage reaches the full charge linear interval or the full discharge linear interval, recording the current time as the first time, and obtaining the charge and discharge capacity of the battery at the current temperature; determining the state of charge of the current battery based on the open-circuit voltage corresponding to the first time; determining the theoretical charge and discharge amount of the battery based on the charge and discharge capacity and the state of charge; when the open-circuit voltage reaches the full charge state or the full discharge state, recording the current time as the second time, and performing time integration on the current of the battery from the first time to the second time to obtain the actual charge and discharge amount of the battery; determining the first SOH of the battery according to the actual charge and discharge amount and the theoretical charge and discharge amount. Therefore, the SOH of the current energy storage system can be quickly calibrated.

Description

Technical Field

[0001] The present invention relates to the field of energy storage, and particularly to a method, device, equipment and medium for SOH calibration. Background Art

[0002] As a core component in industrial and commercial energy storage systems, the performance of batteries directly affects the efficiency, reliability and safety of energy storage systems. The SOH (State Of Health) of a battery refers to the health state of the battery, which can reflect the degree of performance degradation of the battery relative to its initial state.

[0003] In the prior art, the calculation method of the SOH module for industrial and commercial energy storage is usually obtained based on the charge and discharge cycle times and calendar life of the energy storage system. However, since this calculation method is limited by factors such as temperature, DOD (Depth of discharge), and rate, it is difficult to quickly and effectively estimate the SOH of the current system.

[0004] Therefore, how to quickly calibrate the SOH of the current energy storage system is an urgent problem to be solved at present. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a method for SOH calibration, which is used to quickly calibrate the SOH of the current energy storage system. The specific scheme is as follows:

[0006] In a first aspect, the present application provides a method for SOH calibration, including:

[0007] Monitoring the open-circuit voltage and current of the battery. When the open-circuit voltage reaches the full charge linear interval or the full discharge linear interval, record the current time as the first time, and obtain the charge and discharge capacity of the battery at the current temperature;

[0008] Based on the open-circuit voltage corresponding to the first time, determine the current state of charge of the battery;

[0009] Based on the charge and discharge capacity and the state of charge, determine the theoretical charge and discharge amount of the battery;

[0010] When the open-circuit voltage reaches the full charge state or the full discharge state, record the current time as the second time, and perform time integration on the current of the battery from the first time to the second time to obtain the actual charge and discharge amount of the battery;

[0011] Determine the first SOH of the battery according to the actual charge and discharge amount and the theoretical charge and discharge amount.

[0012] Optionally, it further includes:

[0013] Based on the actual charge-discharge amount and the nominal capacity of the battery, determine the second SOH of the battery through the cycle period - SOH table;

[0014] Obtain the storage time of the battery, and based on the storage time, determine the third SOH of the battery through the attenuation table corresponding to the battery.

[0015] Optionally, after calculating the time within the first time to the second time for the current to obtain the actual charge-discharge amount of the battery, it further includes:

[0016] Each time the charge-discharge is successful, the number of successful charge-discharges of the battery is incremented by 1 to determine the total number of successful charge-discharges of the battery within a day;

[0017] Based on the total number of successful charge-discharges, determine the calibration coefficient;

[0018] Based on the calibration coefficient and the preset constraint conditions, determine the first weighting coefficient and the second weighting coefficient; wherein, the sum of the first weighting coefficient, the second weighting coefficient and the calibration coefficient is 1;

[0019] Determine that the first weighting coefficient, the second weighting coefficient and the calibration coefficient are the weighting coefficients corresponding to the second SOH, the third SOH and the comprehensive SOH in sequence; wherein, the comprehensive SOH is obtained by comprehensively calculating all the first SOHs calculated within a day;

[0020] Based on the weighting coefficients, perform weighted calculation on the second SOH, the third SOH and the comprehensive SOH to determine the overall SOH of the battery.

[0021] Optionally, the determining the first weighting coefficient and the second weighting coefficient based on the calibration coefficient and the preset constraint conditions includes:

[0022] Judge whether the calibration coefficient is greater than a preset threshold;

[0023] If it is greater, determine that the second weighting coefficient is 0.02;

[0024] If it is less, determine that the second weighting coefficient is 0.1;

[0025] Calculate the first difference between the sum of the calibration coefficient and the second weighting coefficient and 1, and determine the absolute value of the first difference as the first weighting coefficient.

[0026] Optionally, the determining the theoretical charge-discharge amount of the battery based on the charge-discharge capacity and the state of charge includes:

[0027] When the battery is in the full charge linear range, calculate the second difference between 1 and the state of charge, and determine the product of the charge-discharge capacity and the second difference as the theoretical charge-discharge amount of the battery;

[0028] When the battery is in the full discharge linear range, determine the product of the charge-discharge capacity and the state of charge as the theoretical charge-discharge amount of the battery.

[0029] Optionally, the determining the first SOH of the battery according to the actual charge-discharge amount and the theoretical charge-discharge amount includes:

[0030] Taking the ratio of the actual charge-discharge amount to the theoretical charge-discharge amount as the first SOH of the battery.

[0031] Optionally, the obtaining the charge-discharge capacity of the battery at the current temperature includes:

[0032] Based on the temperature-charge-discharge capacity table, determine the charge-discharge capacity of the battery at the current temperature;

[0033] Or, based on the temperature conversion coefficient at the current temperature and the capacity of the battery at the standard temperature, determine the charge-discharge capacity of the battery at the current temperature.

[0034] In a second aspect, the present application provides an energy storage SOH calibration device, including:

[0035] A time determination module, configured to continuously monitor the open-circuit voltage and current of the battery. When the open-circuit voltage reaches the full charge linear range or the full discharge linear range, record the current time as the first time, and obtain the charge-discharge capacity of the battery at the current temperature;

[0036] A state determination module, configured to determine the state of charge of the current battery based on the open-circuit voltage corresponding to the first time;

[0037] A theoretical power acquisition module, configured to determine the theoretical charge-discharge amount of the battery based on the charge-discharge capacity and the state of charge;

[0038] An actual power acquisition module, configured to record the current time as the second time when the open-circuit voltage reaches the full charge state or the full discharge state, and perform time integration on the current of the battery from the first time to the second time to obtain the actual charge-discharge amount of the battery;

[0039] An SOH acquisition module, configured to determine the first SOH of the battery according to the actual charge-discharge amount and the theoretical charge-discharge amount.

[0040] In a third aspect, the present application provides an electronic device, including:

[0041] A memory for storing a computer program;

[0042] A processor for executing the computer program to implement the SOH calibration method described above.

[0043] In a fourth aspect, the present application provides a computer-readable storage medium for storing a computer program; wherein, when the computer program is executed by a processor, the SOH calibration method described above is implemented.

[0044] As can be seen from the above, when the battery is in the full charge linear range or the full discharge linear range, there is an obvious and stable mapping relationship between its open circuit voltage and SOC (State Of Charge, remaining charge), which can provide accurate SOC data for SOH calculation. Therefore, when determining the theoretical discharge capacity of the battery by calculating the product of the state of charge and the charge and discharge capacity, more accurate results can be obtained. In addition, different from the prior art where calculating SOH requires collecting multi-dimensional data such as the voltage, current, and temperature of the battery for a long time and at high frequencies to determine the SOH of the battery, this solution only needs to calculate the ratio of the actual charge and discharge capacity to the theoretical charge and discharge capacity during one full charge or full discharge process to determine the current SOH of the battery, greatly accelerating the speed of calculating SOH. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] 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 the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0046] Figure 1 It is a flowchart of an SOH calibration method disclosed in the present application;

[0047] Figure 2 It is a specific first SOH calculation flowchart disclosed in the present application;

[0048] Figure 3 It is an OCV-SOC schematic diagram of a lithium iron phosphate battery disclosed in the present application;

[0049] Figure 4 It is a specific SOH calibration method flowchart disclosed in the present application;

[0050] Figure 5 It is a schematic diagram of a calibration coefficient determination process disclosed in the present application;

[0051] Figure 6 It is a schematic diagram of weighted coefficient distribution disclosed in the present application;

[0052] Figure 7 Structural schematic diagram of a SOH calibration device disclosed in the present application;

[0053] Figure 8 Structural diagram of an electronic device disclosed in the present application. Specific embodiments

[0054] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all 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 shall fall within the protection scope of the present invention.

[0055] As a core component in the industrial and commercial energy storage system, the performance of the battery directly affects the efficiency, reliability, and safety of the energy storage system. The battery SOH (State Of Health) refers to the health state of the battery, which can exactly reflect the degree of performance degradation of the battery relative to its initial state.

[0056] In the prior art, the SOH module calculation method for industrial and commercial energy storage is usually calculated based on the charge and discharge cycle times and calendar life of the energy storage system. However, due to the limitations of this calculation method by factors such as temperature, DOD, and rate, it is difficult to quickly and effectively estimate the current system SOH.

[0057] Therefore, the present application provides a SOH calibration scheme to quickly calibrate the SOH of the current energy storage system.

[0058] See Figure 1 、 Figure 2 As shown in, the embodiments of the present invention disclose a SOH calibration method, including:

[0059] Step S11: Monitor the open-circuit voltage and current of the battery. When the open-circuit voltage reaches the full charge linear interval or the full discharge linear interval, record the current time as the first time, and obtain the charge and discharge capacity of the battery at the current temperature;

[0060] In this embodiment, the open-circuit voltage and the charge-discharge current of the battery are continuously monitored. When it is detected that the above open-circuit voltage reaches the full-charge linear range or the full-discharge linear range, the current time is recorded as the first time. At the same time, it is also necessary to determine the charge-discharge capacity of the battery at the current temperature. It can be understood that the charge-discharge process of the battery is essentially a series of electrochemical reactions, which will be affected by temperature, and the internal resistance of the battery will also change with the rise and fall of temperature. Therefore, the charge-discharge capacity of the battery will change at different temperatures. When calculating the SOH, if the actual charge-discharge capacity at the current temperature is not considered, but only based on the rated capacity or the capacity value under other fixed conditions, it will lead to a large deviation between the calculated result of the SOH and the actual health state of the battery. Therefore, in order to accurately calculate the SOH of the battery, it is necessary to obtain the actual charge-discharge capacity at the current temperature for subsequent calculations. There are two ways to obtain the actual charge-discharge capacity at the current temperature

[0061] In a specific embodiment, the charge-discharge capacity of the battery at the current temperature is determined based on the temperature-charge-discharge capacity table. The temperature-charge-discharge capacity table is a data table that shows the change relationship of the charge-discharge capacity of the battery under different temperature conditions, and can intuitively reflect the capacity retention ability of the battery at different temperatures. In addition to obtaining the corresponding temperature-charge-discharge capacity table of the battery through self-experiment, most batteries will be equipped with a specification manual when leaving the factory, which contains the temperature-charge-discharge capacity table. Therefore, the charge-discharge capacity of the battery at the current temperature can also be directly determined by referring to the temperature-charge-discharge capacity table in the specification manual

[0062] In another specific embodiment, based on the temperature conversion coefficient δ of the current temperature temp and the capacity of the battery at the standard temperature, the charge-discharge capacity of the battery at the current temperature is determined. For some batteries that are more affected by temperature, a temperature conversion coefficient table or formula will be provided in the specification manual when leaving the factory. For example Figure 2 As shown, the temperature conversion coefficients specified in the specification manual of a certain battery are as follows

[0063] [15°C to 35°C], δ temp =α 1 ;

[0064] [0°C to 15°C], δ temp =α 2 ;

[0065] [35°C to 50°C], δ temp =α 3 ;

[0066] Based on the different δ corresponding to the above different temperature ranges tempThe size of can be used to calculate the charge and discharge capacity Q of the battery at the current temperature. 额定 .

[0067] In this embodiment, it is necessary to calculate the SOH of the battery in the full charge linear interval or the full discharge linear interval of the battery. It should be noted that the full charge linear interval and the full discharge linear interval generally refer to the interval in which the voltage changes nearly linearly with the state of charge during the charging or discharging process of the battery, but not all batteries have a linear interval. For example, some special-purpose batteries, such as high-temperature batteries or high-power pulse batteries, have relatively complex charging and discharging characteristics due to their working principles and application scenarios, and may not have obvious full charge and full discharge linear intervals. During the charging and discharging process of these batteries, due to the particularity of the internal chemical reaction, the special requirements of the electrode material or the extreme working environment, the changes in parameters such as voltage and capacity may be nonlinear, and are greatly affected by external factors such as temperature and load.

[0068] In this embodiment, according to the charging characteristics of the lithium iron phosphate battery, the voltage of the lithium iron phosphate battery changes rapidly when it is close to being fully charged or fully discharged, forming a full charge linear interval and a full discharge linear interval. Therefore, this scheme can be used for the SOH calculation of the lithium iron phosphate battery.

[0069] Step S12, determining the current state of charge of the battery based on the open circuit voltage corresponding to the first time;

[0070] In this embodiment, after determining the first time, it is also necessary to obtain the open circuit voltage corresponding to the time, so as to determine the current state of charge of the battery according to the open circuit voltage of the battery. It is understandable that for most battery systems, such as lithium-ion batteries, nickel-metal hydride batteries, etc., when the battery is in different states of charge, the different degrees of chemical reactions inside the battery will cause the potential difference between the positive and negative electrodes to be different, thereby showing different voltage values. Therefore, there is a relatively stable corresponding relationship between the open circuit voltage and the state of charge of the battery.

[0071] Furthermore, through a large number of experimental tests and data analysis, the open circuit voltage-state of charge curve corresponding to a specific battery, namely the OCV-SOC curve, can be drawn, and the SOC corresponding to the battery at the current OCV (Open Circuit Voltage) can be determined by comparing the OCV-SOC curve. Figure 3 The OCV-SOC diagram of lithium iron phosphate battery, the horizontal axis is the state of charge of the battery, the vertical axis is the open circuit voltage of the battery, the solid line is the charging curve of the lithium iron phosphate battery, the dotted line is the discharge curve of the lithium iron phosphate battery, and the SOC between [0.9, 1.0] and [0, 0.15] is the linear range of full charge and full discharge of the lithium iron phosphate battery. Figure 2As shown, when it is detected that the open-circuit voltage is within the chg_interval range or the dis_interval range, the state of charge of the current battery can be determined through the above OCV-SOC table, and the current first time T_start is recorded. It can be understood that the above chg_interval range and dis_interval range are the above full-charge linear range and full-discharge linear range.

[0072] It should be noted that the battery needs to be static for a period of time before measuring the open-circuit voltage of the battery. Because during the charging and discharging process of the battery, complex chemical reactions occur inside, resulting in continuous changes in the chemical state and potential distribution on the electrode surface. This change will cause fluctuations in the open-circuit voltage of the battery. After standing for a period of time, the chemical reactions inside the battery will gradually tend to equilibrium, and the concentration of chemical substances and potential distribution on the electrode surface will also tend to be stable. Therefore, the open-circuit voltage measured at this time can accurately reflect the true potential difference inside the battery, so as to more accurately judge the state of charge of the battery.

[0073] Step S13: Determine the theoretical charge and discharge capacity of the battery based on the charge and discharge capacity and the state of charge;

[0074] In this embodiment, by calculating the charge and discharge capacity and the state of charge at the current temperature, the current theoretical charge and discharge capacity of the battery can be obtained.

[0075] In this embodiment, when the battery is in the full-charge linear range, calculate the second difference between 1 and the state of charge, and determine the product of the charge and discharge capacity and the second difference as the theoretical charge and discharge capacity of the battery; when the battery is in the full-discharge linear range, determine the product of the charge and discharge capacity and the state of charge as the theoretical charge and discharge capacity of the battery. It can be understood that when the battery is in the full-discharge linear range, the amount of electricity that can still be discharged needs to be calculated. Therefore, the product of the charge and discharge capacity at the current temperature of the battery and the state of charge can be used as the theoretical charge and discharge capacity of the battery. When the battery is in the full-charge linear range, the amount of electricity that can still be charged needs to be calculated. Therefore, it is necessary to calculate the difference between the charge and discharge capacity at the current temperature and the product of the charge and discharge capacity at the current temperature and the state of charge as the theoretical charge and discharge capacity of the battery.

[0076] Step S14: When the open-circuit voltage reaches the full-charge state or the full-discharge state, record the current time as the second time, and perform time integration on the current of the battery from the first time to the second time to obtain the actual charge and discharge capacity of the battery;

[0077] In this embodiment, when the battery reaches full charge or full discharge, record the current time as the second time, and calculate the discharge power or charge power of the battery from the first time to the second time, that is, the actual charge and discharge capacity of the battery. The specific formula is as follows:

[0078] ;

[0079] Among them, chg_dischg_Cap is the charge and discharge amount of the battery in the full charge linear interval or the full discharge linear interval, T_end is the second time, T_start is the first time, and I is the charge and discharge current of the battery.

[0080] It can be understood that in order to accelerate the speed of obtaining the actual charge and discharge amount, as Figure 3 shown, considering that the open circuit voltage of the lithium iron phosphate battery changes with the SOC much faster in the full charge linear interval and the full discharge linear interval than in the plateau period, so if the battery is in the full charge linear interval at the first time, the second time needs to be recorded when the battery reaches the full charge state; if the battery is in the full discharge linear interval at the first time, the second time needs to be recorded when the battery reaches the full discharge state.

[0081] Step S15: Determine the first SOH of the battery according to the actual charge and discharge amount and the theoretical charge and discharge amount.

[0082] In this embodiment, the current health state of the battery is calculated and determined based on the actual charge and discharge amount and the theoretical charge and discharge amount.

[0083] In this embodiment, the ratio of the actual charge and discharge amount to the theoretical charge and discharge amount is used as the first SOH of the battery. The specific formula is as follows:

[0084] ;

[0085] Among them, SOH quick_cal is the first SOH, SOC is the state of charge corresponding to the open circuit voltage at the first time, and Q 额定 is the charge and discharge capacity at the current temperature.

[0086] It should be noted that the essence of SOH is the ratio of the current capacity of the battery to the initial capacity. As the battery is used and aged, a series of irreversible physical and chemical changes will occur inside the battery, such as the loss of electrode materials, the reduction of active substances, the decomposition of electrolytes, etc. These changes will cause the actual charge and discharge amount of the battery to gradually decrease, while the theoretical charge and discharge amount remains basically unchanged. Therefore, calculating the ratio of the actual charge and discharge amount of the battery to the theoretical charge and discharge amount can intuitively reflect the attenuation degree of the battery capacity, and then judge the SOH of the battery.

[0087] As can be seen from the above, when the battery is in the full charge linear range or the full discharge linear range, there is an obvious and stable mapping relationship between its open circuit voltage and SOC, which can provide accurate SOC data for SOH calculation. Therefore, when calculating the theoretical discharge capacity of the battery by multiplying the state of charge by the charge and discharge capacity, more accurate results can be obtained. In addition, different from the prior art where calculating SOH requires long-term and high-frequency acquisition of multi-dimensional data such as the voltage, current, and temperature of the battery to determine the SOH of the battery, this solution only needs to calculate the ratio of the actual charge and discharge capacity to the theoretical charge and discharge capacity during one full charge or full discharge process to determine the current SOH of the battery, greatly accelerating the speed of calculating SOH.

[0088] In order to make the calculated SOH more accurate, referring to Figure 3 as shown, an embodiment of the present application discloses a specific SOH calibration method, which may include:

[0089] Step S21: Each time the charge and discharge is successful, the charge and discharge success count of the battery is incremented by 1 to determine the total charge and discharge success count of the battery within a day;

[0090] In this embodiment, the charge and discharge success count of the battery is continuously recorded for one day to record the total charge and discharge count of the battery within a day. It can be understood that, as Figure 2 shown, Cnt_success can be accumulated after each calculation of the first SOH and cleared daily to determine that the finally obtained Cnt_success is the charge and discharge success count within a day, that is, the total charge and discharge success count.

[0091] Step S22: Determine a calibration coefficient based on the total charge and discharge success count;

[0092] In this embodiment, the calibration coefficient of the battery can be determined through the total charge and discharge success count of the battery within a day. It can be understood that if only one charge or discharge is performed within a day, the value of the first SOH obtained may deviate greatly from the actual situation. Therefore, as the total charge and discharge count within a day increases, the first SOH is calculated multiple times, making the finally obtained first SOH for weighted calculation more accurate and easier to exclude interference.

[0093] In a specific embodiment, in order to achieve profitability, industrial and commercial energy storage often adopts an application strategy of "two charges and two discharges", that is, charging twice and discharging twice a day, and the total charge and discharge success count under normal circumstances is 4. As Figure 5As shown, during the determination of Cnt_success, whenever it is detected that the highest single-cell voltage of the energy storage system is greater than 3.45V or the lowest single-cell voltage is less than 3.15V, it can be determined that the current energy storage system is in the full charge linear interval or the full discharge linear interval. Therefore, continuously judge whether the above-mentioned highest single-cell voltage reaches 3.65V, i.e., the full charge state, or whether the above-mentioned lowest single-cell voltage reaches 2.75V, i.e., the full discharge state. If so, increment Cnt_success by one. At this time, if the total charge and discharge times of the batteries in the storage system within one day is 4, then determine the calibration coefficient to be 0.9; if the total charge and discharge times of the batteries in the storage system within one day is 3, then determine the calibration coefficient to be 0.8; if the total charge and discharge times of the batteries in the storage system within one day is 2, then determine the calibration coefficient to be 0.6; if the total charge and discharge times of the batteries in the storage system within one day is 1, then determine the calibration coefficient to be 0.4; if the total charge and discharge times of the batteries in the storage system within one day is 0, then determine the calibration coefficient to be 0.1.

[0094] It can be understood that the comprehensive SOH of the energy storage system needs to be calculated only once a day. Therefore, the operation of judging the total number of successful charge and discharge times of the batteries in the energy storage system only needs to be judged once when calculating the comprehensive SOH.

[0095] It should be noted that in order to ensure the accuracy of the first SOH, there is also a maximum value for the total charge and discharge times. The above maximum value depends on the fixed charge and discharge times in the energy storage system.

[0096] Therefore, in the above industrial and commercial energy storage, if the total charge and discharge times of the batteries in the storage system within one day exceed 4, it indicates that the energy storage system may be abnormal on that day, and the first SOH value recorded on that day is also not credible. Therefore, determine the calibration coefficient to be 0.

[0097] Step S23: Determine the first weighting coefficient and the second weighting coefficient based on the calibration coefficient and the preset constraint conditions; wherein, the sum of the first weighting coefficient, the second weighting coefficient and the calibration coefficient is 1.

[0098] In this embodiment, the first weighting coefficient and the second weighting coefficient are determined according to the calibration coefficient. It can be understood that the calibration coefficient is also a weighting coefficient, and the sum of the weighting coefficients is 1.

[0099] In a specific implementation, judge whether the calibration coefficient is greater than the preset threshold; if it is greater, then determine the second weighting coefficient to be 0.02; if it is less, then determine the second weighting coefficient to be 0.1; calculate the first difference between the sum of the calibration coefficient and the second weighting coefficient and 1, and determine the absolute value of the first difference as the first weighting coefficient. Further, as Figure 6As shown, the above preset threshold is set to 0.9, where γ is a calibration coefficient, and α and β are the first weighting coefficient and the second weighting coefficient respectively. At this time, the value of the second weighting coefficient is relatively smaller, which means that its corresponding weight is smaller.

[0100] Step S24: Determine that the first weighting coefficient, the second weighting coefficient, and the calibration coefficient are the weighting coefficients corresponding to the second SOH, the third SOH, and the comprehensive SOH respectively; wherein, the comprehensive SOH is obtained by comprehensively calculating all the first SOHs calculated within one day;

[0101] In this embodiment, the weighting coefficients corresponding to the second SOH, the third SOH, and the comprehensive SOH are determined in sequence, where the comprehensive SOH corresponds to the calibration coefficient, the second SOH corresponds to the first weighting coefficient, and the third SOH corresponds to the second weighting coefficient. It can be understood that multiple first SOHs can be calculated based on the actual charge and discharge amount and the theoretical charge and discharge amount within one day. To avoid the influence of outliers on the calculation result, it is necessary to comprehensively evaluate the above multiple first SOHs, remove obvious outliers, and use comprehensive calculation methods such as the weighted average method and the comprehensive index method to obtain a comprehensive SOH that can reflect all normal data and participate in subsequent weighted calculations.

[0102] In this embodiment, based on the actual charge and discharge amount and the nominal capacity of the battery, the second SOH of the battery is determined through the cycle - SOH table; the storage time of the battery is obtained, and based on the storage time, the third SOH of the battery is determined through the attenuation table corresponding to the battery. To make the calculated battery health degree more accurate, the SOH can also be calculated by multiple methods simultaneously, and the overall SOH calculated by different methods is analyzed to obtain a more accurate and more approximate overall SOH of the actual battery health state.

[0103] Specifically, the second SOH is determined through the cycle number of the battery. The current of the battery is time - integrated to obtain the charge and discharge amount, and this amount is stored in the memory in real - time. The cycle number of the battery can be mapped from the storage capacity and the nominal capacity value. It should be noted that the battery manufacturer will also provide the cycle - SOH table of the battery when the battery leaves the factory. Therefore, the second SOH of the battery can be determined according to the cycle - SOH table.

[0104] Further, the third SOH is determined by the storage time of the battery. As the storage time increases, the capacity of the lithium iron phosphate battery will also decay to a certain extent. The BMS (Battery Management System) controller software can calculate the storage time of the battery in real time and map the third SOH corresponding to the storage time according to the decay table provided by the battery manufacturer. Since industrial and commercial energy storage needs to operate for a long time, this value has a relatively small impact on the overall SOH value and can correspond to the above-mentioned second weighting coefficient.

[0105] Step S25: Based on the weighting coefficients, perform weighted calculations on the second SOH, the third SOH, and the comprehensive SOH to determine the overall SOH of the battery.

[0106] In this embodiment, after determining the weights corresponding to the SOHs obtained by different methods, the overall SOH of the battery is determined through weighted calculation. It can be understood that, compared with calculating the SOH by a single method, using weighted calculation can make the finally obtained SOH more accurate and closer to the actual value. Its specific formula can be:

[0107] ;

[0108] where SOH is the overall SOH, SOH cycle is the second SOH determined by the number of cycles, SOH calendar is the third SOH determined by the storage time, α is the first weighting coefficient, β is the second weighting coefficient, and γ is the calibration coefficient.

[0109] As can be seen from the above, weighted calculations are performed on the SOHs obtained by the three methods for the battery. According to the importance of the first SOH, the weight of the first SOH in the calculation is reasonably planned to perform comprehensive operations on the values of multiple SOHs, making the finally obtained overall SOH more accurate.

[0110] Correspondingly, as shown in Figure 7 this embodiment of the present application also provides an SOH calibration device, which may include:

[0111] A time determination module 11, configured to monitor the open-circuit voltage and current of the battery. When the open-circuit voltage reaches the full charge linear interval or the full discharge linear interval, record the current time as the first time and obtain the charge and discharge capacity of the battery at the current temperature;

[0112] A state determination module 12, configured to determine the current state of charge of the battery based on the open-circuit voltage corresponding to the first time;

[0113] A theoretical charge quantity acquisition module 13, configured to determine the theoretical charge and discharge quantity of the battery based on the charge and discharge capacity and the state of charge;

[0114] The actual power acquisition module 14 is configured to record the current time as the second time when the open-circuit voltage reaches the full charge state or the full discharge state, and perform time integration on the current of the battery from the first time to the second time to obtain the actual charge and discharge amount of the battery;

[0115] The first SOH acquisition module 15 is configured to determine the first SOH of the battery according to the actual charge and discharge amount and the theoretical charge and discharge amount.

[0116] As can be seen from the above, when the battery is in the full charge linear interval or the full discharge linear interval, there is an obvious and stable mapping relationship between its open-circuit voltage and SOC, which can provide accurate SOC data for SOH calculation. Therefore, when determining the theoretical discharge amount of the battery by calculating the product of the state of charge and the charge and discharge capacity, a more accurate result can be obtained. In addition, different from the prior art in which calculating the SOH requires collecting multi-dimensional data such as the voltage, current, and temperature of the battery for a long time and at high frequencies to determine the SOH of the battery, this solution only needs to calculate the ratio of the actual charge and discharge amount to the theoretical charge and discharge amount during one full charge or full discharge process to determine the current SOH of the battery, greatly accelerating the speed of calculating the SOH.

[0117] In some specific embodiments, the SOH calibration device further includes:

[0118] The second SOH acquisition module is configured to determine the second SOH of the battery based on the actual charge and discharge amount and the nominal capacity of the battery through a cycle- SOH table;

[0119] The third SOH acquisition module is configured to obtain the storage time of the battery and determine the third SOH of the battery based on the storage time through the attenuation table corresponding to the battery.

[0120] In some specific embodiments, the first SOH acquisition module 15 further includes:

[0121] The number acquisition unit is configured to add 1 to the successful charge and discharge times of the battery each time the charge and discharge is successful to determine the total successful charge and discharge times of the battery within one day;

[0122] The first coefficient acquisition unit is configured to determine a calibration coefficient based on the total successful charge and discharge times;

[0123] The second coefficient acquisition unit is configured to determine a first weighting coefficient and a second weighting coefficient based on the calibration coefficient and a preset constraint condition; wherein, the sum of the first weighting coefficient, the second weighting coefficient and the calibration coefficient is 1.

[0124] A coefficient distribution unit, configured to determine that the first weighting coefficient, the second weighting coefficient, and the calibration coefficient are the weighting coefficients corresponding to the second SOH, the third SOH, and the comprehensive SOH in sequence; wherein, the comprehensive SOH is obtained by comprehensively calculating all the first SOHs calculated within one day;

[0125] An overall SOH determination unit, configured to perform weighted calculation on the second SOH, the third SOH, and the comprehensive SOH based on the weighting coefficients to determine the overall SOH of the battery.

[0126] In some specific embodiments, the second coefficient acquisition unit may specifically include:

[0127] Judge whether the calibration coefficient is greater than a preset threshold;

[0128] If it is greater, determine that the second weighting coefficient is 0.02;

[0129] If it is less, determine that the second weighting coefficient is 0.1;

[0130] Calculate a first difference between the sum of the calibration coefficient and the second weighting coefficient and 1, and determine the absolute value of the first difference as the first weighting coefficient.

[0131] In some specific embodiments, the theoretical power acquisition module 13 includes:

[0132] A first theoretical power acquisition unit, configured to calculate a second difference between 1 and the state of charge when the battery is in the full charge linear interval, and determine the product of the charge and discharge capacity and the second difference as the theoretical charge and discharge amount of the battery;

[0133] A second theoretical power acquisition unit, configured to determine the product of the charge and discharge capacity and the state of charge as the theoretical charge and discharge amount of the battery when the battery is in the full discharge linear interval.

[0134] In some specific embodiments, the first SOH acquisition module 15 includes:

[0135] A first SOH determination unit, configured to use the ratio of the actual charge and discharge amount to the theoretical charge and discharge amount as the first SOH of the battery.

[0136] In some specific embodiments, the time determination module 11 includes:

[0137] A first capacity acquisition unit, configured to determine the charge and discharge capacity of the battery at the current temperature based on the temperature-charge and discharge capacity table;

[0138] A second capacity acquisition unit, configured to determine the charge-discharge capacity of the battery at the current temperature based on the temperature conversion coefficient at the current temperature and the capacity of the battery at the standard temperature of the battery.

[0139] Further, an embodiment of the present application also discloses an electronic device. Figure 8 It is a structural diagram of an electronic device 20 shown according to an exemplary embodiment. The content in the figure should not be considered as any limitation on the scope of use of the present application. The electronic device 20 may specifically include: at least one processor 21, at least one memory 22, a power supply 23, a communication interface 24, an input / output interface 25, and a communication bus 26. Among them, the memory 22 is used to store a computer program, and the computer program is loaded and executed by the processor 21 to implement the relevant steps in the SOH calibration method disclosed in any of the foregoing embodiments. In addition, the electronic device 20 in this embodiment may specifically be an electronic computer.

[0140] In this embodiment, the power supply 23 is used to provide operating voltages for each hardware device on the electronic device 20; the communication interface 24 can create a data transmission channel between the electronic device 20 and external devices, and the communication protocol it follows is any communication protocol applicable to the technical solution of the present application, and specific limitations are not imposed on it here; the input / output interface 25 is used to obtain external input data or output data to the outside, and its specific interface type can be selected according to specific application needs, and specific limitations are not imposed here.

[0141] In addition, as a carrier for resource storage, the memory 22 may be a read-only memory, a random access memory, a disk, or an optical disc, etc. The resources stored thereon may include an operating system 221, a computer program 222, etc., and the storage method may be short-term storage or permanent storage.

[0142] Among them, the operating system 221 is used to manage and control each hardware device on the electronic device 20 and the computer program 222, and it may be Windows Server, Netware, Unix, Linux, etc. The computer program 222 may further include a computer program capable of completing other specific tasks in addition to the computer program capable of implementing the SOH calibration method executed by the electronic device 20 disclosed in any of the foregoing embodiments.

[0143] Further, the present application also discloses a computer-readable storage medium for storing a computer program; wherein, when the computer program is executed by a processor, the SOH calibration method disclosed above is implemented. For the specific steps of this method, reference may be made to the corresponding content disclosed in the foregoing embodiments, and details are not described herein again.

[0144] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple. For the relevant parts, reference can be made to the description in the method section.

[0145] Those skilled in the art can further realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed in this article can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the components and steps of the examples have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0146] The steps of the methods or algorithms described in combination with the embodiments disclosed in this article can be directly implemented by hardware, software modules executed by a processor, or a combination of the two. The software modules can be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium well-known in the technical field.

[0147] Finally, it should also be noted that in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0148] The technical solutions provided in this application have been introduced in detail above. Specific examples are used in this article to elaborate on the principles and implementation manners of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application; at the same time, for those of ordinary skill in the art, according to the idea of this application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. A SOH calibration method, characterized in that: include: Monitor the open circuit voltage and current of the battery, and when the open circuit voltage reaches the full charge linear interval or the full discharge linear interval, record the current time as the first time, and obtain the chargeable and dischargeable capacity of the battery at the current temperature; wherein the linear relationship in the full charge linear interval or the full discharge linear interval is the linear relationship between the open circuit voltage and the state of charge, the full charge linear interval is an interval in which the voltage changes rapidly when the battery is close to being fully charged, and the full discharge linear interval is an interval in which the voltage changes rapidly when the battery is close to being fully discharged; determining a current state of charge of the battery based on the open circuit voltage corresponding to the first time; Based on the chargeable and dischargeable capacity and the state of charge, the theoretical chargeable and dischargeable amount of the battery is determined; the theoretical chargeable and dischargeable amount of the battery is the amount of electricity that can be theoretically charged into or discharged from the battery within the full charge linear interval or the full discharge linear interval at the current temperature; When the open circuit voltage reaches a fully charged state or a fully discharged state, the current time is recorded as a second time, and the current of the battery from the first time to the second time is time-integrated to obtain an actual charge and discharge amount of the battery; Determine a first SOH of the battery according to the actual charge and discharge amount and the theoretical charge and discharge amount; The method further comprises: Based on the actual charge and discharge amount and the nominal capacity of the battery, determine the second SOH of the battery through a cycle-SOH table; obtain the shelf time of the battery, and based on the shelf time, determine the third SOH of the battery through a decay table corresponding to the battery; After performing time integration on the current of the battery from the first time to the second time to obtain the actual charge and discharge amount of the battery, the method further includes: Each time charging and discharging is successful, the number of successful charging and discharging of the battery is increased by 1 to determine the total number of successful charging and discharging of the battery in one day; based on the total number of successful charging and discharging, a calibration coefficient is determined; based on the calibration coefficient and a preset constraint condition, a first weighting coefficient and a second weighting coefficient are determined; wherein the sum of the first weighting coefficient, the second weighting coefficient and the calibration coefficient is 1; the first weighting coefficient, the second weighting coefficient and the calibration coefficient are determined to be weighting coefficients corresponding to the second SOH, the third SOH and the comprehensive SOH in turn; wherein the comprehensive SOH is obtained by combining all the first SOHs calculated in one day; based on the weighting coefficient, the second SOH, the third SOH and the comprehensive SOH are weightedly calculated to determine the overall SOH of the battery; The determining the first weighting coefficient and the second weighting coefficient based on the calibration coefficient and the preset constraint condition comprises: Determine whether the calibration coefficient is greater than a preset threshold; if greater, determine the second weighting coefficient to be 0.02; if less, determine the second weighting coefficient to be 0.1; calculate a first difference between the sum of the calibration coefficient and the second weighting coefficient and 1, and determine the absolute value of the first difference to be the first weighting coefficient; The determining, based on the chargeable and dischargeable capacity and the state of charge, a theoretical chargeable and dischargeable amount of the battery comprises: When the battery is in the full charge linear interval, the second difference between 1 and the state of charge is calculated, and the product of the chargeable and dischargeable capacity and the second difference is determined to be the theoretical chargeable amount of the battery; when the battery is in the full discharge linear interval, the product of the chargeable and dischargeable capacity and the state of charge is determined to be the theoretical dischargeable amount of the battery.

2. The SOH calibration method according to claim 1, characterized in that: The determining the first SOH of the battery according to the actual charge and discharge amount and the theoretical charge and discharge amount includes: The ratio of the actual charge and discharge amount to the theoretical charge and discharge amount is used as the first SOH of the battery.

3. The SOH calibration method according to claim 1, characterized in that: The obtaining of the chargeable and dischargeable capacity of the battery at the current temperature includes: Determining the chargeable and dischargeable capacity of the battery at the current temperature based on the temperature-chargeable and dischargeable capacity table; Or, based on the temperature conversion coefficient of the current temperature and the capacity of the battery at the standard temperature, the chargeable and dischargeable capacity of the battery at the current temperature is determined.

4. A storage SOH calibration device, characterized in that: include: A time determination module, used for continuously monitoring the open circuit voltage and current of the battery, and when the open circuit voltage reaches the full charge linear interval or the full discharge linear interval, recording the current time as the first time, and obtaining the chargeable and dischargeable capacity of the battery at the current temperature; wherein the linear relationship in the full charge linear interval or the full discharge linear interval is the linear relationship between the open circuit voltage and the state of charge, the full charge linear interval is an interval in which the voltage changes rapidly when the battery is close to being fully charged, and the full discharge linear interval is an interval in which the voltage changes rapidly when the battery is close to being fully discharged; a state determination module, configured to determine a current state of charge of the battery based on the open circuit voltage corresponding to the first time; A theoretical power acquisition module, used to determine the theoretical chargeable and dischargeable amount of the battery based on the chargeable and dischargeable capacity and the state of charge; the theoretical chargeable and dischargeable amount of the battery is the amount of power that can be theoretically charged or discharged by the battery within the full charge linear interval or the full discharge linear interval at the current temperature; an actual power acquisition module, configured to record the current time as a second time when the open circuit voltage reaches a fully charged state or a fully discharged state, and perform time integration on the current of the battery from the first time to the second time to obtain the actual charge and discharge capacity of the battery; An SOH acquisition module, configured to determine a first SOH of the battery according to the actual charge and discharge amount and the theoretical charge and discharge amount; The energy storage SOH calibration device is specifically used for: Based on the actual charge and discharge amount and the nominal capacity of the battery, determine the second SOH of the battery through a cycle-SOH table; obtain the shelf time of the battery, and based on the shelf time, determine the third SOH of the battery through a decay table corresponding to the battery; The energy storage SOH calibration device is specifically used for: Each time charging and discharging is successful, the number of successful charging and discharging of the battery is increased by 1 to determine the total number of successful charging and discharging of the battery in one day; based on the total number of successful charging and discharging, a calibration coefficient is determined; based on the calibration coefficient and a preset constraint condition, a first weighting coefficient and a second weighting coefficient are determined; wherein the sum of the first weighting coefficient, the second weighting coefficient and the calibration coefficient is 1; the first weighting coefficient, the second weighting coefficient and the calibration coefficient are determined to be weighting coefficients corresponding to the second SOH, the third SOH and the comprehensive SOH in turn; wherein the comprehensive SOH is obtained by combining all the first SOHs calculated in one day; based on the weighting coefficient, the second SOH, the third SOH and the comprehensive SOH are weightedly calculated to determine the overall SOH of the battery; The energy storage SOH calibration device is specifically used for: Determine whether the calibration coefficient is greater than a preset threshold; if greater, determine the second weighting coefficient to be 0.02; if less, determine the second weighting coefficient to be 0.1; calculate a first difference between the sum of the calibration coefficient and the second weighting coefficient and 1, and determine the absolute value of the first difference to be the first weighting coefficient; The theoretical power acquisition module is specifically used for: When the battery is in the full charge linear interval, the second difference between 1 and the state of charge is calculated, and the product of the chargeable and dischargeable capacity and the second difference is determined to be the theoretical chargeable amount of the battery; when the battery is in the full discharge linear interval, the product of the chargeable and dischargeable capacity and the state of charge is determined to be the theoretical dischargeable amount of the battery.

5. An electronic device, characterized in that: include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the SOH calibration method according to any one of claims 1 to 3.

6. A computer-readable storage medium, characterized in that: Used to store a computer program; wherein, when the computer program is executed by a processor, the SOH calibration method according to any one of claims 1 to 3 is implemented.

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