Method and device for estimating SOE of energy storage system and related equipment

Abstract

The invention relates to an energy storage system SOE estimation method and device and related equipment. The method comprises the following steps: acquiring the current capacity and rated capacity of the energy storage system; determining the state of the energy storage system, and setting the full charge voltage of the energy storage system in the state; the current cell average voltage of the energy storage system is obtained, the current cell average voltage is compared with the voltage threshold value of the energy storage system in the state, and the final cell average voltage is obtained; and performing SOE estimation according to the current capacity, the rated capacity, the full charge voltage and the final average voltage of the battery cell to obtain the SOE of the energy storage system in the state, thereby solving the technical problem of calculation deviation caused by dependence on a big data model and a complex algorithm in the prior art, achieving high-precision and low-calculation-burden SOE estimation, and improving the calculation efficiency. And the reliability of the energy storage system and the energy management efficiency are improved.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a method, device and related equipment for estimating the state of energy (SOE) of an energy storage system. Background Art

[0002] With the development of the energy storage industry, energy storage systems need to operate more efficiently and stably. The concept of SOE (energy state of energy storage battery) has been introduced in the field of energy storage. SOE can reflect the operating status of the energy storage system from another perspective. Currently, there are neural networks, OCV open circuit voltage method, Kalman filter algorithm, etc. to estimate SOE, but these algorithms based on big data require a huge amount of data to support them. When the big data model is not accurate enough, the results obtained will also be biased.

[0003] For the current energy storage system, multiple cells are connected in series or in parallel, which is the basic framework of the energy storage system. Therefore, it is impossible to control the capacity of dozens or hundreds of cells at the same level for the entire system. Most of them are balanced and grouped at the factory. This processing method cannot ensure that the voltage and capacity of each cell are highly consistent during operation, which brings great difficulties to the SOE calculation of big data type. As the energy storage system is charged and discharged, chemical crystals will be generated inside the cell, and the capacity of the cell will decay with the number of charge and discharge cycles. It takes a lot of time to control the degree of decay, and it is difficult to use the data as the original data of the big data model when it is inaccurate. During the charging and discharging process, the voltage and current data are in a state of change, and the above algorithm will cause greater errors in the calculation results.

[0004] Therefore, when estimating the SOE of energy storage systems, the existing technology relies on big data models and complex algorithms, which require huge amounts of data support. In addition, it is difficult to ensure the consistency of the voltage and capacity of each battery cell when multiple battery cells are connected in series or in parallel, resulting in deviations in the calculation results. In particular, when the voltage and current data change greatly during the charging and discharging process, the error further increases.

[0005] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0006] The embodiments of the present application provide a method, device and related equipment for estimating SOE of an energy storage system, so as to at least solve the technical problem of calculation deviation caused by reliance on big data models and complex algorithms in the prior art.

[0007] According to one aspect of an embodiment of the present application, a method for estimating SOE of an energy storage system is provided, comprising: obtaining a current capacity and a rated capacity of an energy storage system; determining a state of the energy storage system, and setting a full charge voltage of the energy storage system in the state; wherein the state of the energy storage system comprises at least one of the following: a charging state, a discharging state, and a static state; obtaining a current average cell voltage of the energy storage system, comparing the current average cell voltage with a voltage threshold in the state of the energy storage system, and obtaining a final average cell voltage; estimating SOE according to the current capacity, the rated capacity, the full charge voltage, and the final average cell voltage, and obtaining the SOE of the energy storage system in the state.

[0008] Optionally, setting the full charge voltage of the energy storage system in the state includes: when the state of the energy storage system is the charging state, setting a first preset voltage to the full charge voltage; wherein the first preset voltage is the voltage of the battery cell in the energy storage system when it is fully charged; when the state of the energy storage system is the discharging state or the static state, setting a second preset voltage to the full charge voltage; wherein the second preset voltage is the voltage of the battery cell in the energy storage system after it is fully charged and static for a period of time.

[0009] Optionally, when the state of the energy storage system is the charging state, the voltage threshold includes a first preset voltage, the first preset voltage is the voltage of the battery cells in the energy storage system when they are fully charged, and the current battery cell average voltage is compared with the voltage threshold in the state of the energy storage system to obtain the final battery cell average voltage, including: judging whether the current battery cell average voltage is greater than or equal to the first preset voltage; if the current battery cell average voltage is greater than or equal to the first preset voltage, setting the first preset voltage as the final battery cell average voltage; if the current battery cell average voltage is less than the first preset voltage, setting the current battery cell average voltage to the final battery cell average voltage.

[0010] Optionally, when the state of the energy storage system is the discharge state, the voltage threshold includes a third preset voltage, and the third preset voltage is the voltage of the battery cells in the energy storage system after they are discharged and left stationary for a period of time. The current battery cell average voltage is compared with the voltage threshold in the state of the energy storage system to obtain the final battery cell average voltage, including: determining whether the current battery cell average voltage is less than or equal to the third preset voltage; if the current battery cell average voltage is less than or equal to the third preset voltage, setting the third preset voltage as the final battery cell average voltage; if the current battery cell average voltage is greater than the third preset voltage, setting the current battery cell average voltage to the final battery cell average voltage.

[0011] Optionally, when the state of the energy storage system is the static state, the voltage threshold includes a second preset voltage and a third preset voltage, the second preset voltage is the voltage of the battery cells in the energy storage system after being fully charged and standing for a period of time, and the third preset voltage is the voltage of the battery cells in the energy storage system after being fully discharged and standing for a period of time, and the current battery cell average voltage is compared with the voltage threshold in the state of the energy storage system to obtain the final battery cell average voltage, including: judging whether the current battery cell average voltage is less than or equal to the third preset voltage; if the current battery cell average voltage is less than or equal to the third preset voltage, setting the third preset voltage as the final battery cell average voltage; if the current battery cell average voltage is greater than the third preset voltage, judging whether the current battery cell average voltage is greater than or equal to the second preset voltage; if the current battery cell average voltage is greater than or equal to the second preset voltage, setting the second preset voltage as the final battery cell average voltage; if the current battery cell average voltage is less than the second preset voltage, setting the current battery cell average voltage to the final battery cell average voltage.

[0012] Optionally, SOE estimation is performed according to the current capacity, the rated capacity, the full charge voltage and the final average cell voltage to obtain the SOE in the state of the energy storage system, including: multiplying the current capacity by the final average cell voltage to obtain the current remaining energy of the energy storage system; multiplying the rated capacity by the full charge voltage to obtain the maximum storage energy of the energy storage system; dividing the current remaining energy of the energy storage system by the maximum storage energy of the energy storage system to obtain the SOE in the state of the energy storage system.

[0013] According to another aspect of an embodiment of the present application, there is provided an estimation device for SOE of an energy storage system, comprising: a capacity acquisition module, for acquiring a current capacity and a rated capacity of an energy storage system; a voltage setting module, for determining a state of the energy storage system and setting a full charge voltage of the energy storage system in the state; wherein the state of the energy storage system comprises at least one of the following: a charging state, a discharging state and a static state; a voltage comparison module, for acquiring a current average cell voltage of the energy storage system, and comparing the current average cell voltage with a voltage threshold in the state of the energy storage system to obtain a final average cell voltage; and an SOE estimation module, for performing SOE estimation according to the current capacity, the rated capacity, the full charge voltage and the final average cell voltage to obtain the SOE in the state of the energy storage system.

[0014] According to another aspect of an embodiment of the present application, an electronic device is provided, comprising: a processor, and a memory storing a program, wherein the program comprises instructions, and when the instructions are executed by the processor, the processor executes any one of the above-mentioned methods for estimating the SOE of an energy storage system.

[0015] According to another aspect of an embodiment of the present application, a non-transitory machine-readable medium storing computer instructions is provided, wherein the computer instructions are used to enable the computer to execute the method for estimating the SOE of an energy storage system described above.

[0016] According to another aspect of an embodiment of the present application, a computer program product is provided, including a computer program. Optionally, when the computer program is executed by a processor of a computer, the computer is used to enable the computer to execute the method for estimating the SOE of an energy storage system described above.

[0017] In the embodiment of the present application, the current capacity and rated capacity of the energy storage system are obtained; the state of the energy storage system is determined, and the full charge voltage of the energy storage system in the state is set; wherein the state of the energy storage system includes at least one of the following: charging state, discharging state and static state; the current average voltage of the battery cells of the energy storage system is obtained, and the current average voltage of the battery cells is compared with the voltage threshold in the state of the energy storage system to obtain the final average voltage of the battery cells; SOE is estimated according to the current capacity, rated capacity, full charge voltage and final average voltage of the battery cells to obtain the SOE in the state of the energy storage system, that is, the embodiment of the present application solves the technical problem of calculation deviation caused by reliance on big data models and complex algorithms in the prior art by dynamically setting the full charge voltage, introducing the voltage threshold comparison mechanism and combining the ampere-hour accumulation method and voltage processing, so as to achieve high-precision and low-computational burden SOE estimation, and improve the reliability of the energy storage system and the technical effect of energy management efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other embodiments can be obtained based on these drawings without creative work.

[0019] Figure 1 A flowchart of a method for estimating SOE of an energy storage system provided in an embodiment of the present application; Figure 2 A flowchart of a method for estimating SOE of an energy storage system provided for an optional embodiment of the present application; Figure 3 A schematic diagram of an energy storage system SOE estimation device provided in an embodiment of the present application; Figure 4 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0020] The embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present application are shown in the accompanying drawings, it should be understood that the embodiments of the present application can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the embodiments of the present application. It should be understood that the drawings and embodiments of the present application are only for exemplary purposes and are not intended to limit the scope of protection of the present application.

[0021] According to one aspect of an embodiment of the present application, a method for estimating SOE of an energy storage system is provided. Figure 1 A flowchart of a method for estimating SOE of an energy storage system provided in an embodiment of the present application, such as Figure 1 As shown, the method comprises the following steps: Step S102, obtaining the current capacity and rated capacity of the energy storage system.

[0022] For example, by using a battery management system (BMS) to monitor and calculate the current capacity of the energy storage system in real time and using the calibrated rated capacity as a reference, the accuracy of capacity calculation can be improved, avoiding the impact of capacity attenuation caused by cell aging or increased charge and discharge cycles on the estimation results.

[0023] Step S104, determining the state of the energy storage system and setting the full charge voltage of the energy storage system in the state; wherein the state of the energy storage system includes at least one of the following: a charging state, a discharging state, and a static state.

[0024] According to the state of the energy storage system (charging, discharging or static), the corresponding full charge voltage is dynamically set. This dynamic setting of the full charge voltage can better adapt to the voltage change characteristics of the battery cell in different states and reduce the error caused by state changes. For example, charging state: the full charge voltage is set to 3600mV (the voltage when the battery cell is fully charged). Discharging state: the full charge voltage is set to 3350mV (the static full charge voltage after the battery cell is fully charged and static for a period of time). Static state: Based on the comparison between the average voltage of the battery cell and the threshold, select 3350mV (static full charge voltage) or 3000mV (static discharge voltage) as the full charge voltage.

[0025] Step S106, obtaining the current average cell voltage of the energy storage system, comparing the current average cell voltage with the voltage threshold value under the state of the energy storage system, and obtaining the final average cell voltage.

[0026] In each state, the final average cell voltage is determined through a voltage threshold comparison mechanism. This voltage threshold comparison mechanism can use a fixed voltage value for SOE estimation when the cell is nearly fully charged or fully discharged, avoiding the impact of voltage fluctuations on the results. For example, charging state: If the current average cell voltage is greater than or equal to 3600mV, 3600mV is used as the final average cell voltage; otherwise, the current average cell voltage is used. Discharging state or static state: If the current average cell voltage is less than or equal to 3000mV, 3000mV is used as the final average cell voltage; otherwise, continue to determine whether it is greater than or equal to 3350mV, and then decide which voltage value to use.

[0027] Step S108, performing SOE estimation according to the current capacity, rated capacity, full charge voltage and final average voltage of the battery cells to obtain the SOE of the energy storage system in the state.

[0028] The current remaining energy is obtained by multiplying the current capacity by the final average voltage of the battery cell; the maximum storage energy is obtained by multiplying the rated capacity by the full charge voltage; and the current remaining energy is divided by the maximum storage energy to obtain the SOE of the energy storage system in the state it is in. This SOE estimation method based on the ampere-hour accumulation method and voltage processing can achieve a more accurate energy state estimation without relying on complex big data models.

[0029] In the embodiment of the present application, the current capacity and rated capacity of the energy storage system are obtained; the state of the energy storage system is determined, and the full charge voltage of the energy storage system in the state is set; wherein the state of the energy storage system includes at least one of the following: charging state, discharging state and static state; the current average voltage of the battery cells of the energy storage system is obtained, and the current average voltage of the battery cells is compared with the voltage threshold in the state of the energy storage system to obtain the final average voltage of the battery cells; SOE is estimated according to the current capacity, rated capacity, full charge voltage and final average voltage of the battery cells to obtain the SOE in the state of the energy storage system, that is, the embodiment of the present application solves the technical problem of calculation deviation caused by reliance on big data models and complex algorithms in the prior art by dynamically setting the full charge voltage, introducing the voltage threshold comparison mechanism and combining the ampere-hour accumulation method and voltage processing, so as to achieve high-precision and low-computational burden SOE estimation, and improve the reliability of the energy storage system and the technical effect of energy management efficiency.

[0030] It should be noted that the voltage threshold in the embodiment of the present application can be flexibly set according to the needs of the application scenario.

[0031] As an optional embodiment, setting the full charge voltage of the energy storage system in the state includes: when the energy storage system is in the charging state, setting the first preset voltage to the full charge voltage; wherein the first preset voltage is the voltage of the battery cell in the energy storage system when it is fully charged; when the energy storage system is in the discharging state or the static state, setting the second preset voltage to the full charge voltage; wherein the second preset voltage is the voltage of the battery cell in the energy storage system after being fully charged and static for a period of time.

[0032] Optionally, when the energy storage system is in a charging state, the first preset voltage (3600mV) is set as the full charge voltage. At this time, the first preset voltage represents the voltage when the battery cell reaches a full charge state during the charging process. This voltage value is determined based on the characteristics of the lithium iron phosphate battery to ensure that the actual charging state of the battery cell can be accurately reflected during the charging process.

[0033] Optionally, when the energy storage system is in a discharge state or a static state, the second preset voltage (3350mV) is set as the full charge voltage. The second preset voltage is called the static full charge voltage, which refers to the stable voltage after the battery cell is fully charged and left to stand for a period of time. For the discharge state, using the static full charge voltage as a reference can more accurately estimate the remaining energy state of the battery cell during the discharge process. For the static state, using the static full charge voltage can avoid voltage fluctuations due to self-discharge or other factors, thereby providing a more stable SOE estimate.

[0034] In the embodiment of the present application, by distinguishing different system states and setting corresponding full charge voltages, the error caused by state changes can be reduced and the estimation accuracy of SOE can be improved. Different full charge voltages are set in different states, fully considering the voltage change characteristics of the battery cell during the charging and discharging process, so that the SOE estimation is more in line with the actual working conditions.

[0035] As an optional embodiment, when the energy storage system is in a charging state, the voltage threshold includes a first preset voltage, the first preset voltage is the voltage of the battery cells in the energy storage system when they are fully charged, and the current battery cell average voltage is compared with the voltage threshold in the state of the energy storage system to obtain the final battery cell average voltage, including: determining whether the current battery cell average voltage is greater than or equal to the first preset voltage; if the current battery cell average voltage is greater than or equal to the first preset voltage, setting the first preset voltage as the final battery cell average voltage; if the current battery cell average voltage is less than the first preset voltage, setting the current battery cell average voltage as the final battery cell average voltage.

[0036] Optionally, when the energy storage system is in a charging state, the first preset voltage is set to 3600mV, which is the voltage when the battery cell is fully charged. The voltage of each battery cell in the energy storage system is collected in real time, and the average voltage of the battery cells of the single-cluster energy storage system is calculated. The current average voltage of the battery cell is compared with the first preset voltage (3600mV) to determine whether the current average voltage of the battery cell is greater than or equal to the first preset voltage. If the current average voltage of the battery cell is greater than or equal to the first preset voltage (3600mV), the first preset voltage (3600mV) is set as the final average voltage of the battery cell. This indicates that the battery cell is close to or has reached a fully charged state. If the current average voltage of the battery cell is less than the first preset voltage (3600mV), the current average voltage of the battery cell is set as the final average voltage of the battery cell. This indicates that the battery cell is not yet fully charged and needs to continue charging.

[0037] Furthermore, the SOE of the energy storage system is further calculated based on the final determined average cell voltage, combined with the current capacity and rated capacity calculated by the ampere-hour accumulation method. In the charging state, the full energy voltage of the cell is set to 3600mV for SOE calculation.

[0038] In an embodiment of the present application, by introducing a voltage threshold comparison mechanism, it is ensured that the cell voltage will not exceed its full charge voltage during the charging process, thereby avoiding the occurrence of overcharging. At the same time, when the cell is close to the full charge voltage, the voltage parameters in the SOE calculation can be adjusted in time, thereby improving the accuracy of the SOE estimation. This method can use the actual measured average voltage for SOE calculation when the cell is not fully charged, and use a fixed full charge voltage for calculation when the cell is close to full, thereby reducing the error caused by voltage fluctuations. This method fully considers the voltage change characteristics of the lithium iron phosphate battery during the charging process, ensuring the accuracy of the SOE estimation. In particular, when the cell is close to full, the use of a fixed full charge voltage can effectively cope with small fluctuations in the cell voltage, providing a more stable SOE estimation result.

[0039] As an optional embodiment, when the energy storage system is in a discharging state, the voltage threshold includes a third preset voltage, which is the voltage of the battery cells in the energy storage system after they are discharged and left stationary for a period of time. The current battery cell average voltage is compared with the voltage threshold in the state of the energy storage system to obtain the final battery cell average voltage, including: determining whether the current battery cell average voltage is less than or equal to the third preset voltage; if the current battery cell average voltage is less than or equal to the third preset voltage, setting the third preset voltage as the final battery cell average voltage; if the current battery cell average voltage is greater than the third preset voltage, setting the current battery cell average voltage as the final battery cell average voltage.

[0040] Optionally, when the energy storage system is in a discharging state, the third preset voltage is set to 3000mV, which is the static empty voltage after the battery cell is discharged and left to stand for a period of time. This voltage value reflects the stable voltage reached by the battery cell after it is fully discharged and left to stand for a period of time. The voltage of each battery cell in the energy storage system is collected in real time, and the average voltage of the battery cells in the single-cluster energy storage system is calculated.

[0041] Compare the current average cell voltage with the third preset voltage (3000mV) to determine whether the current average cell voltage is less than or equal to the third preset voltage. If the current average cell voltage is less than or equal to the third preset voltage (3000mV), set the third preset voltage (3000mV) as the final average cell voltage. This indicates that the cell is close to or has reached a fully discharged state. If the current average cell voltage is greater than the third preset voltage (3000mV), set the current average cell voltage as the final average cell voltage. This indicates that the cell is not fully discharged and still has a certain amount of remaining energy.

[0042] Furthermore, the SOE of the energy storage system is further calculated based on the final determined average cell voltage, combined with the current capacity and rated capacity calculated by the ampere-hour accumulation method. In the discharge state, the full energy voltage of the cell is set to the static full charge voltage of 3350mV for SOE calculation.

[0043] In the embodiment of the present application, by introducing a voltage threshold comparison mechanism, it is ensured that the cell voltage will not be lower than its emptying voltage during the discharge process, thereby avoiding the occurrence of over-discharge. At the same time, when the cell is close to the emptying voltage, the voltage parameters in the SOE calculation can be adjusted in time, thereby improving the accuracy of SOE estimation. The method can use the actual measured average voltage to calculate SOE when the cell is not fully discharged, and use a fixed emptying voltage for calculation when the cell is close to fully discharged, thereby reducing the error caused by voltage fluctuations. The method fully considers the voltage variation characteristics of the lithium iron phosphate battery during the discharge process, thereby ensuring the accuracy of SOE estimation. In particular, when the cell is close to fully discharged, the use of a fixed emptying voltage can effectively cope with small fluctuations in the cell voltage, providing a more stable SOE estimation result. During the discharge process, the cell voltage may fluctuate due to self-discharge or other factors. By setting the third preset voltage as the static emptying voltage, the system can provide a stable reference voltage when the cell is close to fully discharged, thereby avoiding the influence of voltage fluctuations on SOE estimation and improving the overall stability of the system.

[0044] As an optional embodiment, when the energy storage system is in a static state, the voltage threshold includes a second preset voltage and a third preset voltage, the second preset voltage is the voltage of the battery cells in the energy storage system after being fully charged and static for a period of time, and the third preset voltage is the voltage of the battery cells in the energy storage system after being discharged and static for a period of time, and the current battery cell average voltage is compared with the voltage threshold in the state of the energy storage system to obtain the final battery cell average voltage, including: judging whether the current battery cell average voltage is less than or equal to the third preset voltage; if the current battery cell average voltage is less than or equal to the third preset voltage, setting the third preset voltage as the final battery cell average voltage; if the current battery cell average voltage is greater than the third preset voltage, judging whether the current battery cell average voltage is greater than or equal to the second preset voltage; if the current battery cell average voltage is greater than or equal to the second preset voltage, setting the second preset voltage as the final battery cell average voltage; if the current battery cell average voltage is less than the second preset voltage, setting the current battery cell average voltage to the final battery cell average voltage.

[0045] Optionally, the second preset voltage is set to 3350mV, which is the static full charge voltage after the battery cell is fully charged and left to stand for a period of time. The third preset voltage is set to 3000mV, which is the static empty voltage after the battery cell is fully discharged and left to stand for a period of time. The voltage of each battery cell in the energy storage system is collected in real time, and the average voltage of the battery cells in the single cluster energy storage system is calculated. The current average voltage of the battery cell is compared with the third preset voltage (3000mV) to determine whether the current average voltage of the battery cell is less than or equal to the third preset voltage. If the current average voltage of the battery cell is less than or equal to the third preset voltage (3000mV), the third preset voltage (3000mV) is set as the final average voltage of the battery cell. This indicates that the battery cell has approached or reached a fully discharged state. If the current average voltage of the battery cell is greater than the third preset voltage (3000mV), proceed to the next step of comparison: determine whether the current average voltage of the battery cell is greater than or equal to the second preset voltage (3350mV). If the current average cell voltage is greater than or equal to the second preset voltage (3350mV), the second preset voltage (3350mV) is set as the final average cell voltage. This indicates that the cell is close to or has reached a fully charged state. If the current average cell voltage is less than the second preset voltage (3350mV), the current average cell voltage is set as the final average cell voltage. This indicates that the cell is neither fully discharged nor fully charged, but is in an intermediate state.

[0046] Furthermore, the SOE of the energy storage system is further calculated based on the final average cell voltage, combined with the current capacity and rated capacity calculated by the ampere-hour accumulation method. In the static state, the static full charge voltage (3350mV) and static discharge voltage (3000mV) are used as references to ensure a more accurate SOE estimation.

[0047] In an embodiment of the present application, by introducing two voltage thresholds (a second preset voltage and a third preset voltage), the actual state of the battery cell can be more accurately reflected in a static state. Whether it is close to full charge or close to full discharge, SOE estimation can be performed by a fixed voltage value, reducing the error caused by voltage fluctuations. This method can use the actual measured average voltage to calculate SOE when the battery cell is in an intermediate state, and use a fixed voltage value for calculation when the battery cell is close to full or fully discharged, thereby improving the accuracy of SOE estimation. This method fully considers the voltage change characteristics of lithium iron phosphate batteries in a static state, ensuring the accuracy of SOE estimation. In particular, when the battery cell is close to full or fully discharged, the use of a fixed voltage value can effectively cope with small fluctuations in the battery cell voltage and provide a more stable SOE estimation result.

[0048] As an optional embodiment, SOE estimation is performed according to the current capacity, rated capacity, full charge voltage and final average cell voltage to obtain the SOE of the energy storage system in the state, including: multiplying the current capacity by the final average cell voltage to obtain the current remaining energy of the energy storage system; multiplying the rated capacity by the full charge voltage to obtain the maximum storage energy of the energy storage system; dividing the current remaining energy of the energy storage system by the maximum storage energy of the energy storage system to obtain the SOE of the energy storage system in the state.

[0049] The above current capacity is the energy currently stored in the energy storage system, in Ah (ampere-hour), which is monitored and calculated in real time by the BMS. The above rated capacity is the nominal capacity of the energy storage system, that is, the maximum energy that can be stored under ideal conditions, in Ah. The above full charge voltage is the voltage when the battery cell is fully charged, and the specific value depends on the type of battery cell. For example, the full charge voltage of a lithium iron phosphate battery is usually 3600mV. The above final average battery cell voltage is the final average battery cell voltage determined by comparing the voltage threshold according to the state of the energy storage system (charging, discharging or static).

[0050] Optionally, the calculated SOE value is output to a user or a control system for monitoring the energy state of the energy storage system and performing operations such as charge and discharge management and load distribution accordingly.

[0051] In an embodiment of the present application, by introducing the final average voltage of the battery cell as a key parameter for calculating the current remaining energy, the method can more accurately reflect the actual working state of the battery cell. In particular, when the battery cell is close to being fully charged or fully discharged, a fixed voltage value is used for calculation, which reduces the error caused by voltage fluctuations and improves the accuracy of SOE estimation. This method combines the current integration method (ampere-hour accumulation method) and voltage processing, and can achieve more accurate SOE estimation without relying on complex models, and is suitable for various working conditions. Through accurate SOE estimation, users can better understand the energy state of the energy storage system and optimize the energy management strategy. For example, charge in time when the battery is low, or reasonably distribute the load when the battery is sufficient to avoid unnecessary energy waste. This method can also be used to predict the remaining available time of the energy storage system, helping users to plan in advance and ensure the stable operation of the system.

[0052] The optional embodiments of the present application are described in detail below in conjunction with lithium iron phosphate batteries in the field of energy storage.

[0053] The optional embodiment of the present application provides a method for estimating the SOE of lithium iron phosphate batteries suitable for the field of energy storage. Based on the macroscopic concept of energy conservation, it bypasses more complex calculation methods such as big data models, and obtains the real effective capacity of the energy storage system through capacity calibration, without taking into account heat loss and power loss of other external devices. This can ensure the accuracy of capacity calculation and SOE to the greatest extent. The specific steps are as follows: 1. System capacity calculation: First, the BMS system collects the charging and discharging current (the sampling resolution should preferably be higher than one thousandth). If the energy storage system is not charging at a constant current, the current will change with the charging and discharging process, so the hysteresis of the current sampling should be kept within 100ms as much as possible (that is, the current current data is updated once within 100ms). The accuracy deviation of the current sampling and the sampling hysteresis of the current will cause the ampere-hour accumulation to always have a deviation, and the calculated capacity deviation will gradually increase with the current change.

[0054] The remaining capacity is calculated by ampere-hour accumulation. If the accuracy of the ampere-hour accumulated capacity is to be high, it needs to be optimized from two directions. The first is to meet the current sampling accuracy and hysteresis mentioned above. The second is that the timer or operation cycle of the battery management system of the energy storage system needs to be very accurate. At present, most of the BMS used in energy storage systems are single-chip microcomputers or ARM processors, and the integration method also adopts discrete calculation, so the timing cycle requirements are very high.

[0055] The capacity decay of the energy storage system is introduced to further improve the calculation accuracy of the system capacity (i.e. rated capacity calibration). When the energy storage system is fully charged and discharged (i.e. full to empty), the real capacity is calculated, and then the calculated capacity is used as the current rated capacity of the energy storage system to participate in the SOE calculation.

[0056] The above ampere-hour accumulation method can calculate the actual capacity of the current system. The product of capacity and cell voltage is the current remaining energy of the system. When the system charge and discharge state changes, the full charge voltage of the system will also have different performance.

[0057] 2. Voltage processing: The cell voltage data of the energy storage system is the second parameter for calculating SOE. For a single-cluster energy storage system, the average value of the single cell voltage is needed to calculate the SOE of the energy storage system.

[0058] At the same time, the full energy voltage of the battery cell will be different when the energy storage system is in different charging and discharging states. Take lithium iron phosphate batteries as an example. The full charge voltage during charging is 3600mV, the empty voltage during discharging is 2800mV, and the static full charge voltage when the system is at rest is 3350mV (static full charge voltage: the stable voltage after the battery cell is fully charged and left at rest for a period of time), the static empty voltage when the system is at rest is 3000mV (static empty voltage: the stable voltage after the battery cell is discharged and left at rest for a period of time), and the rated voltage is 3200mV.

[0059] 3. Calculate SOE according to system status: When the system is charging: When charging, the current capacity of the energy storage system is the ampere-hour integral calculation value, and the rated capacity is the capacity of the system after calibration. The full energy voltage of the battery cell needs to be set to 3600mV during the charging process. The SOE calculation formula during charging is as follows: When the system is discharged: When discharging, the full energy voltage of the battery cell is the static full charge voltage of 3350mV, and the calculation formula is as follows: When the system is at rest: When the system is at rest, the full energy voltage of the battery cell is the static full charge voltage of 3350mV, and the calculation formula is as follows: 4. SOE filtering and de-jittering: The SOE of the energy storage system cannot decay when it is not discharged, and the SOE of the energy storage system cannot increase when it is not charged. When the cell voltage is 3000mV lower than the static empty voltage and the energy storage system is not charged or discharged, it means that the current system has been discharged, and the current calculated average voltage is the static empty voltage.

[0060] When the system is at rest, if the average voltage is higher than the static full charge voltage of 3350mV, it means that the system is fully charged and the current average voltage is the static full charge voltage.

[0061] Figure 2 A flowchart of a method for estimating SOE of an energy storage system provided in an optional embodiment of the present application is shown in FIG. Figure 2As shown, first obtain the current capacity of the energy storage system. Determine whether the energy storage system is in a charging and discharging state. If it is in a charging and discharging state, determine whether it is charging or discharging. If it is in a charging state: set the full charge voltage to 3600mV; determine whether the current voltage (corresponding to the current average voltage of the battery cell mentioned above) is less than 3600mV; if yes, keep the current voltage at 3600mV; if no, obtain the current voltage. If it is in a discharging state: set the full charge voltage to 3350mV; determine whether the current voltage is less than 3000mV; if yes, keep the current voltage at 3000mV; if no, obtain the current voltage. If it is not in a charging and discharging state: set the full charge voltage to 3350mV; determine whether the current voltage is less than 3000mV; if yes, keep the current voltage at 3000mV; if no, determine whether the current voltage is greater than 3350mV; if yes, save the current voltage at 3350mV; if no, obtain the current voltage. SOE estimation is performed based on the current capacity, rated capacity, full charge voltage, and the final average voltage of the battery cell.

[0062] Through the above steps, the full charge voltage can be dynamically adjusted according to the state of the energy storage system, and the final average cell voltage can be determined through the voltage threshold comparison mechanism, thereby achieving high-precision SOE estimation.

[0063] Compared with the prior art, the optional embodiments of the present application have the following advantages: (1) The optional embodiment of the present application proposes a method for estimating the SOE of lithium iron phosphate in the field of energy storage, which uses less data and computing power to calculate the SOE, thereby improving the overall stability and reliability of the system.

[0064] (2) By accumulating data at an hourly rate, the initial investment in big data is reduced, saving R&D costs and complexity.

[0065] (3) More accurate, with smaller errors. The ampere-hour accumulation and voltage acquisition can currently achieve relatively accurate values ​​in the energy storage industry. This SOE solution only introduces these two variables, which can make the SOE calculation more accurate.

[0066] According to another aspect of an embodiment of the present application, a device for estimating SOE of an energy storage system is provided. Figure 3 A schematic diagram of an estimation device for SOE of an energy storage system provided in an embodiment of the present application, such as Figure 3 As shown, the energy storage system SOE estimation device includes: a capacity acquisition module 302, a voltage setting module 304, a voltage comparison module 306 and a SOE estimation module 308. The energy storage system SOE estimation device is described in detail below.

[0067] The capacity acquisition module 302 is used to acquire the current capacity and rated capacity of the energy storage system; A voltage setting module 304, connected to the capacity acquisition module 302, is used to determine the state of the energy storage system and set the full charge voltage of the energy storage system in the state; wherein the state of the energy storage system includes at least one of the following: charging state, discharging state and static state; A voltage comparison module 306 is connected to the voltage setting module 304 and is used to obtain the current average voltage of the battery cells of the energy storage system, compare the current average voltage of the battery cells with the voltage threshold value under the state of the energy storage system, and obtain the final average voltage of the battery cells; The SOE estimation module 308 is connected to the voltage comparison module 306 and is used to estimate the SOE according to the current capacity, rated capacity, full charge voltage and final average cell voltage to obtain the SOE of the energy storage system.

[0068] In an embodiment of the present application, the device adopts the method of obtaining the current capacity and rated capacity of the energy storage system; determining the state of the energy storage system, and setting the full charge voltage of the energy storage system in the state; wherein the state of the energy storage system includes at least one of the following: charging state, discharging state and static state; obtaining the current average voltage of the battery cells of the energy storage system, comparing the current average voltage of the battery cells with the voltage threshold of the state of the energy storage system, and obtaining the final average voltage of the battery cells; performing SOE estimation according to the current capacity, rated capacity, full charge voltage and final average voltage of the battery cells, and obtaining the SOE of the state of the energy storage system, that is, the embodiment of the present application solves the technical problem of calculation deviation caused by reliance on big data models and complex algorithms in the prior art by dynamically setting the full charge voltage, introducing the voltage threshold comparison mechanism and combining the ampere-hour accumulation method and voltage processing, so as to achieve the technical effect of realizing high-precision and low-computational burden SOE estimation and improving the reliability of the energy storage system and the energy management efficiency.

[0069] It should be noted here that the above-mentioned capacity acquisition module 302, voltage setting module 304, voltage comparison module 306 and SOE estimation module 308 correspond to steps S102 to S108 in the method embodiment, and the examples and application scenarios implemented by the above-mentioned modules and corresponding steps are the same, but are not limited to the contents disclosed in the above-mentioned method embodiment.

[0070] Optionally, the voltage setting module 304 includes: a first voltage setting unit, which is used to set a first preset voltage to a full charge voltage when the energy storage system is in a charging state; wherein the first preset voltage is the voltage of a battery cell in the energy storage system when it is fully charged; and a second voltage setting unit, which is used to set a second preset voltage to a full charge voltage when the energy storage system is in a discharging state or a static state; wherein the second preset voltage is the voltage of a battery cell in the energy storage system after it is fully charged and static for a period of time.

[0071] Optionally, when the energy storage system is in a charging state, the voltage threshold includes a first preset voltage, which is the voltage of the battery cells in the energy storage system when they are fully charged. The voltage comparison module 306 includes: a first judgment unit, used to judge whether the current average battery cell voltage is greater than or equal to the first preset voltage; a third voltage setting unit, used to set the first preset voltage as the final average battery cell voltage if the current average battery cell voltage is greater than or equal to the first preset voltage; and a fourth voltage setting unit, used to set the current average battery cell voltage as the final average battery cell voltage if the current average battery cell voltage is less than the first preset voltage.

[0072] Optionally, when the energy storage system is in a discharging state, the voltage threshold includes a third preset voltage, which is the voltage of the battery cells in the energy storage system after they are discharged and left stationary for a period of time. The voltage comparison module 306 includes: a second judgment unit, used to judge whether the current average battery cell voltage is less than or equal to the third preset voltage; a fifth voltage setting unit, used to set the third preset voltage as the final average battery cell voltage if the current average battery cell voltage is less than or equal to the third preset voltage; and a sixth voltage setting unit, used to set the current average battery cell voltage as the final average battery cell voltage if the current average battery cell voltage is greater than the third preset voltage.

[0073] Optionally, when the energy storage system is in a static state, the voltage threshold includes a second preset voltage and a third preset voltage, the second preset voltage is the voltage of the battery cells in the energy storage system after being fully charged and standing for a period of time, and the third preset voltage is the voltage of the battery cells in the energy storage system after being discharged and standing for a period of time, and the above-mentioned voltage comparison module 306 includes: a third judgment unit, used to judge whether the current average battery cell voltage is less than or equal to the third preset voltage; a seventh voltage setting unit, used to set the third preset voltage as the final average battery cell voltage if the current average battery cell voltage is less than or equal to the third preset voltage; a fourth judgment unit, used to judge whether the current average battery cell voltage is greater than the third preset voltage, if the current average battery cell voltage is greater than the third preset voltage; an eighth voltage setting unit, used to set the second preset voltage as the final average battery cell voltage if the current average battery cell voltage is greater than or equal to the second preset voltage; a ninth voltage setting unit, used to set the current average battery cell voltage to the final average battery cell voltage if the current average battery cell voltage is less than the second preset voltage.

[0074] Optionally, the SOE estimation module 308 includes: a first calculation unit, used to multiply the current capacity by the final average voltage of the battery cell to obtain the current remaining energy of the energy storage system; a second calculation unit, used to multiply the rated capacity by the full charge voltage to obtain the maximum storage energy of the energy storage system; and a third calculation unit, used to divide the current remaining energy of the energy storage system by the maximum storage energy of the energy storage system to obtain the SOE of the energy storage system in the state it is in.

[0075] According to another aspect of an embodiment of the present application, an electronic device is provided, including: a processor, and a memory storing a program, wherein the program includes instructions, and when the instructions are executed by the processor, the processor executes the method for estimating the SOE of an energy storage system according to an embodiment of the present application.

[0076] According to another aspect of an embodiment of the present application, a non-transitory machine-readable medium storing computer instructions is provided, where the computer instructions are used to enable a computer to execute the method for estimating the SOE of an energy storage system according to an embodiment of the present application.

[0077] According to another aspect of an embodiment of the present application, a computer program product is provided, including a computer program. Optionally, when the computer program is executed by a processor of a computer, the computer is used to enable the computer to execute the method for estimating the SOE of an energy storage system according to an embodiment of the present application.

[0078] refer to Figure 4 , the structural block diagram of the electronic device that can be used as the server or client of the embodiment of the present application will now be described, which is an example of the hardware device that can be applied to various aspects of the present application. The electronic device is intended to represent various forms of digital electronic computer equipment, such as laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices and other similar computing devices. The components shown herein, their connections and relationships, and their functions are only examples, and are not intended to limit the implementation of the present application described and / or required herein.

[0079] like Figure 4 As shown, the electronic device includes a computing unit 401, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 402 or a computer program loaded from a storage unit 408 to a random access memory (RAM) 403. In RAM 403, various programs and data required for the operation of the electronic device can also be stored. The computing unit 401, ROM 402, and RAM 403 are connected to each other via a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0080] Multiple components in the electronic device are connected to the I / O interface 405, including: an input unit 406, an output unit 407, a storage unit 408, and a communication unit 409. The input unit 406 can be any type of device that can input information to the electronic device, and the input unit 406 can receive input digital or character information, and generate key signal input related to user settings and / or function control of the electronic device. The output unit 407 can be any type of device that can present information, and can include but is not limited to a display, a speaker, a video / audio output terminal, a vibrator, and / or a printer. The storage unit 408 can include but is not limited to a disk, an optical disk. The communication unit 409 allows the electronic device to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks, and can include but is not limited to a modem, a network card, an infrared communication device, and a wireless communication transceiver, such as a Bluetooth device, a WiFi device, a WiMax device, a cellular communication device, and / or the like.

[0081] The computing unit 401 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the computing unit 401 include, but are not limited to, a CPU, a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing units, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The computing unit 401 performs the various methods and processes described above. For example, in some embodiments, the method embodiments of the present application may be implemented as a computer program, which is tangibly contained in a machine-readable medium, such as a storage unit 408. In some embodiments, part or all of the computer program may be loaded and / or installed on an electronic device via ROM 402 and / or communication unit 409. In some embodiments, the computing unit 401 may be configured to perform the above method in any other appropriate manner (e.g., by means of firmware).

[0082] The computer program for implementing the method of the embodiment of the present application can be written in any combination of one or more programming languages. These computer programs can be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor or controller, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program can be executed entirely on the machine, partially on the machine, partially on the machine as a stand-alone software package and partially on a remote machine, or entirely on a remote machine or server.

[0083] In the context of the embodiments of the present application, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or apparatus. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable signal medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared systems, devices, or equipment, or any suitable combination of the foregoing. More specific examples of machine-readable storage media may include electrical connections based on one or more lines, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0084] It should be noted that the term "including" and its variations used in the embodiments of the present application are open inclusions, that is, "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments". The modifications of "one" and "multiple" mentioned in the embodiments of the present application are illustrative and not restrictive. Those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0085] The various steps described in the method implementation methods provided in the embodiments of the present application can be performed in different orders and / or in parallel. In addition, the method implementation methods may include additional steps and / or omit the steps shown. The scope of protection of the present application is not limited in this respect.

[0086] The term "embodiment" in this specification refers to specific features, structures or characteristics described in conjunction with the embodiment that can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily mean the same embodiment, nor does it mean that it is mutually exclusive with other embodiments and is independent or optional. The various embodiments in this specification are described in a related manner, and the same or similar parts between the various embodiments refer to each other. In particular, for the device, equipment, and system embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts refer to the partial description of the method embodiment.

[0087] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of patent protection. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the attached claims.

Claims

1. A method for estimating SOE of an energy storage system, characterized in that: include: Obtain the current capacity and rated capacity of the energy storage system; Determine the state of the energy storage system and set the full charge voltage of the energy storage system in the state; wherein the state of the energy storage system includes at least one of the following: charging state, discharging state and static state; Obtaining a current average cell voltage of the energy storage system, comparing the current average cell voltage with a voltage threshold value under a state of the energy storage system, and obtaining a final average cell voltage; The SOE of the energy storage system is estimated according to the current capacity, the rated capacity, the full charge voltage and the final average voltage of the battery cells to obtain the SOE of the energy storage system in the state.

2. The method for estimating SOE of an energy storage system according to claim 1, characterized in that: Setting the full charge voltage of the energy storage system in the state includes: When the energy storage system is in the charging state, the first preset voltage is set to the full charge voltage; wherein the first preset voltage is the voltage when the battery cell in the energy storage system is fully charged; When the energy storage system is in the discharge state or the static state, the second preset voltage is set to the full charge voltage; wherein the second preset voltage is the voltage of the battery cell in the energy storage system after it is fully charged and static for a period of time.

3. The method for estimating SOE of an energy storage system according to claim 1, characterized in that: When the state of the energy storage system is the charging state, the voltage threshold includes a first preset voltage, which is the voltage of a cell in the energy storage system when it is fully charged, and the current cell average voltage is compared with the voltage threshold in the state of the energy storage system to obtain a final cell average voltage, including: Determine whether the current average voltage of the battery cell is greater than or equal to the first preset voltage; If the current average cell voltage is greater than or equal to the first preset voltage, setting the first preset voltage as the final average cell voltage; If the current battery cell average voltage is less than the first preset voltage, the current battery cell average voltage is set as the final battery cell average voltage.

4. The method for estimating SOE of an energy storage system according to claim 1, characterized in that: When the energy storage system is in the discharge state, the voltage threshold includes a third preset voltage, and the third preset voltage is the voltage of the battery cells in the energy storage system after being discharged and standing for a period of time. The current battery cell average voltage is compared with the voltage threshold in the state of the energy storage system to obtain the final battery cell average voltage, including: Determine whether the current average voltage of the battery cell is less than or equal to the third preset voltage; If the current battery cell average voltage is less than or equal to the third preset voltage, setting the third preset voltage as the final battery cell average voltage; If the current battery cell average voltage is greater than the third preset voltage, the current battery cell average voltage is set as the final battery cell average voltage.

5. The method for estimating SOE of an energy storage system according to claim 1, characterized in that: When the state of the energy storage system is the static state, the voltage threshold includes a second preset voltage and a third preset voltage, the second preset voltage is the voltage of the battery cell in the energy storage system after being fully charged and standing for a period of time, and the third preset voltage is the voltage of the battery cell in the energy storage system after being fully discharged and standing for a period of time, and the current battery cell average voltage is compared with the voltage threshold in the state of the energy storage system to obtain the final battery cell average voltage, including: Determine whether the current average voltage of the battery cell is less than or equal to the third preset voltage; If the current battery cell average voltage is less than or equal to the third preset voltage, setting the third preset voltage as the final battery cell average voltage; If the current average voltage of the battery cells is greater than the third preset voltage, determining whether the current average voltage of the battery cells is greater than or equal to the second preset voltage; If the current battery cell average voltage is greater than or equal to the second preset voltage, setting the second preset voltage as the final battery cell average voltage; If the current battery cell average voltage is less than the second preset voltage, the current battery cell average voltage is set as the final battery cell average voltage.

6. The method for estimating SOE of an energy storage system according to any one of claims 1 to 5, characterized in that: The SOE is estimated according to the current capacity, the rated capacity, the full charge voltage and the final average voltage of the battery cells to obtain the SOE of the energy storage system in the state, including: Multiplying the current capacity by the final average voltage of the battery cells to obtain the current remaining energy of the energy storage system; Multiplying the rated capacity by the full charge voltage to obtain the maximum storage energy of the energy storage system; The current remaining energy of the energy storage system is divided by the maximum storage energy of the energy storage system to obtain the SOE of the energy storage system in the state.

7. A device for estimating SOE of an energy storage system, characterized in that: include: A capacity acquisition module is used to obtain the current capacity and rated capacity of the energy storage system; A voltage setting module, used to determine the state of the energy storage system and set the full charge voltage of the energy storage system in the state; wherein the state of the energy storage system includes at least one of the following: a charging state, a discharging state, and a static state; A voltage comparison module is used to obtain the current average voltage of the battery cells of the energy storage system, compare the current average voltage of the battery cells with the voltage threshold value under the state of the energy storage system, and obtain the final average voltage of the battery cells; The SOE estimation module is used to estimate the energy state SOE according to the current capacity, the rated capacity, the full charge voltage and the final average voltage of the battery cells to obtain the SOE of the energy storage system in the state.

8. An electronic device comprising: A processor, and a memory storing a program, wherein the program includes instructions, and when the instructions are executed by the processor, the processor executes the method for estimating the SOE of an energy storage system according to any one of claims 1 to 6.

9. A non-transitory machine-readable medium storing computer instructions, characterized in that: The computer instructions are used to enable the computer to execute the method for estimating the SOE of an energy storage system according to any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor of a computer, it is used to make the computer execute the method for estimating SOE of an energy storage system according to any one of claims 1 to 6.

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