Charge / discharge control system and charge / discharge control method for an energy storage system capable of setting an upper limit on charge / discharge output according to the charge state.

Abstract

To provide a system and a method that most efficiently use an ESS in an extent that a problem of battery safety is not induced.SOLUTION: An ESS charge / discharge control system according to the present invention comprises: a data collection unit for collecting ESS operation record data; a data learning unit for generating an OCV-SoC table on the basis of the ESS operation record data; a voltage upper limit calculation unit for calculating a charge / discharge voltage upper limit on the basis of a V-SoC table during charging and a V-SoC table during discharging calculated on the basis of the OCV-SoC table and the ESS operation record data; an output upper limit calculation unit for calculating SoC ranges of charging and discharging in accordance with the calculated voltage upper limit, and calculating an output upper limit in accordance with the calculated SoC ranges of charging and discharging; and an ESS operation unit for executing an ESS charge / discharge command on the basis of the output upper limit in accordance with the SoC ranges of charging and discharging, and the calculated SoC ranges of charging and discharging.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a charge / discharge system and method for an energy storage system, and more specifically, to an ESS charge / discharge system and method for setting an upper limit on the charge / discharge output according to the SoC so that the ESS can be used most efficiently without inducing battery safety problems such as fire. [Background technology]

[0002] An Energy Storage System (ESS) is a device that stores generated electricity and makes it available again when electricity is needed. Therefore, the use of ESS makes it possible to utilize energy more efficiently in the stages before generation, transmission, substations, distribution, and storage. In addition, while the quality of electricity generated from new bioenergy sources such as solar and wind power was not uniform when connected to the power grid because it was difficult to predict the exact output and the output fluctuation rate was high, the use of ESS makes it possible to use electricity of a more uniform quality.

[0003] In order to utilize such ESSs more safely and efficiently, research and development of various battery safety and efficiency-related technologies is underway. In particular, control technologies such as monitoring of various parameters of each battery cell, including charge state, temperature, voltage, and current; calculation of the State of Charge (SoC); cell balancing to adjust the degree of charging and discharging of each battery cell in a balanced manner; and protection functions such as overvoltage, overcurrent, and overcharge prevention are being actively researched and developed.

[0004] In particular, among these ESS control technologies, the most important ESS charging methods are the constant current method, the constant power method, and the constant voltage method. Of these, the constant power method (hereinafter referred to as "CP") is most frequently used due to its ease of control according to instantaneous energy levels.

[0005] CP charging uses a constant power supply, resulting in a characteristic where the current decreases as the battery voltage rises during charging. Due to this characteristic of voltage rise during charging, the ESS (Electrical System) may reach the safe operating voltage of the battery cells before the battery is fully charged, leading to ESS system failure. Since such ESS failures occur because the voltage falls outside the safe operating voltage range of the cells, proper voltage management is essential.

[0006] However, conventionally, attempts were made to estimate the battery's SoC through the Open Circuit Voltage (OCV) value and then control the voltage based on this. However, the SoC estimated through OCV differed from the SoC value obtained based on the actual voltage during battery charging and discharging, resulting in different voltage changes depending on the output and SoC. This presented problems in utilizing the SoC during ESS operation. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Korean Registered Patent Publication No. 10-2493221 [Overview of the project] [Problems that the invention aims to solve]

[0008] Therefore, the present invention was devised to solve the aforementioned problems, and its objective is to provide an ESS charging and discharging system that can use the ESS most efficiently within a range that does not induce battery safety problems by pre-calculating the maximum output that can be driven by the SoC during the charging and discharging process.

[0009] However, the diverse problems that this invention aims to solve are not limited to these, and are included in the specific details described in the detailed description of this invention. [Means for solving the problem]

[0010] The ESS charge / discharge control system of the present invention may include: a data acquisition unit that collects ESS operation record data; a data learning unit that generates an OCV-SoC table based on the ESS operation record data; a voltage limit calculation unit that calculates a charge / discharge voltage limit based on the OCV-SoC table, a V-SoC table during charging calculated based on the ESS operation record data, and a V-SoC table during discharging; an output limit calculation unit that calculates the range of the SoC for charging and discharging according to the calculated voltage limit and calculates an output limit according to the calculated range of the SoC for charging and discharging; and an ESS operation unit that executes ESS charge / discharge commands based on the range of the SoC for charging and discharging and the output limit according to the calculated range of the SoC for charging and discharging.

[0011] In this case, the voltage upper limit calculation unit can calculate the inflection point, the battery's safe upper limit, and the lower limit of the SoC value based on the OCV-SoC table.

[0012] Furthermore, the voltage limit calculation unit can calculate the upper limit of the voltage during charging based on the V-SoC table during charging, the inflection point, and the SoC of the battery's safe upper limit.

[0013] Furthermore, the voltage limit calculation unit can calculate the upper limit of the voltage during discharge based on the V-SoC table during discharge, the reverse point of the inflection point, and the battery's safe lower limit SoC.

[0014] Furthermore, the output limit calculation unit can cluster power-SoC data based on ESS operation record data, derive SoC sections during charging based on at least a portion of the V-SoC tables and charging voltage limits of the clustered clusters, and derive output limits for each SoC section during charging.

[0015] Furthermore, the output limit calculation unit can derive the SoC section during discharge based on the inverse point of the SoC, which is the maximum value of the SoC section during charging, and derive the output limit for each SoC section during discharge.

[0016] On the one hand, the ESS charge-discharge control system further includes a charge-discharge planning unit, and the ESS operation unit can transmit a control command to the ESS according to the planned charge-discharge amount and charge-discharge time to perform charge-discharge.

[0017] Also, when the current instantaneous voltage value exceeds the safe operating voltage range of the ESS, the ESS operation unit can ignore the charge-discharge plan and interrupt the charge-discharge.

[0018] Also, when the current power amount collected through the data collection unit is lower than the minimum base power, the ESS operation unit ignores the charge-discharge plan, executes a discharge command to equalize the minimum base power, and can interrupt the charge-discharge if there is no remaining battery capacity.

[0019] In addition, the ESS charge-discharge control system further includes a SoC estimation unit. The ESS operation unit transmits a charge-discharge command to the ESS according to the charge-discharge plan set by the charge-discharge planning unit, and can interrupt the charge-discharge if the remaining battery capacity is insufficient or the battery is fully charged according to the SoC estimated by the SoC estimation unit.

[0020] Also, the ESS operation unit transmits a charge-discharge command to the ESS according to the charge-discharge plan set by the charge-discharge planning unit, and can generate a control command for the ESS based on the output upper limit for each SoC interval calculated by the output upper limit calculation unit.

Advantages of the Invention

[0021] Therefore, according to the present invention, an ESS charge-discharge system that can most efficiently use the ESS can be obtained within a range that does not induce problems with battery safety by calculating in advance the maximum output that can be driven at the SoC during the charge-discharge process.

[0022] The effects of the present invention are not limited to the contents exemplified above, and further various effects are included in this specification.

Brief Description of the Drawings

[0023] [Figure 1] Figure 1 is a block diagram showing an ESS charge / discharge control system according to an embodiment of the present invention. [Figure 2] Figure 2 is a flowchart illustrating the charge and discharge operation of the ESS charge and discharge control system according to an embodiment of the present invention. [Figure 3] Figure 3 is a flowchart illustrating the steps for calculating the upper limit of the ESS charge / discharge voltage according to one embodiment of the present invention. [Figure 4] Figure 4 is a graph showing an OCV-SoC according to an embodiment of the present invention. [Figure 5] Figure 5 is a graph showing the V-SoC during charging operation according to an embodiment of the present invention. [Figure 6] Figure 6 is a graph showing the V-SoC during discharge operation according to an embodiment of the present invention. [Figure 7] Figure 7 is a flowchart illustrating the steps for calculating the upper limit of the ESS charge / discharge output according to one embodiment of the present invention. [Figure 8] Figure 8 is a graph showing the power-SoC relationship to past charging data in ESS charging and discharging according to an embodiment of the present invention. [Figure 9] Figure 9 is a V-SoC graph during CP charging operation at a specific power level according to an embodiment of the present invention. [Figure 10] Figure 10 is a V-SoC graph of CP charging operation at a specific power level according to an embodiment of the present invention. [Figure 11] Figure 11 shows the charge / discharge power control interval based on SoC data according to an embodiment of the present invention. [Figure 12] Figure 12 shows the charge / discharge power control interval based on SoC data according to an embodiment of the present invention. [Figure 13] Figure 13 is a diagram showing the charge / discharge power control section based on SoC data according to an embodiment of the present invention. [Figure 14] Figure 14 is a graph showing the charge / discharge operation plan and actual operation when using conventional ESS charge / discharge technology. [Figure 15]Figure 15 is a graph showing the charge / discharge operation plan and actual operation during ESS charge / discharge operation according to an embodiment of the present invention. [Modes for carrying out the invention]

[0024] Embodiments of the present invention will be described in detail below with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below and can be embodied in a variety of different forms. The following embodiments are provided to fully disclose the present invention and to allow a person with ordinary skill to fully understand the scope of the invention. Also, for the sake of clarity, the sizes of components in the drawings may be exaggerated or reduced.

[0025] However, the following embodiments are provided so that the invention may be fully understood by those who are ordinary skill in the art, and can be modified in various other ways; the scope of the invention is not limited to the embodiments described below.

[0026] On the other hand, when a specification states throughout that a certain part "includes" a certain component, this does not exclude other components unless otherwise stated, and means that other components may be further included.

[0027] The aforementioned objectives and features should become even clearer from the detailed description that follows, which is related to the attached drawings, and accordingly, a person with ordinary skill in the art to which this invention belongs will be able to easily implement the technical idea of ​​the invention.

[0028] Next, an ESS charge / discharge control system according to an embodiment of the present invention will be described in detail with reference to Figure 1.

[0029] Referring to Figure 1, the ESS charge / discharge control system 1000 according to an embodiment of the present invention may include an analysis unit 100 and an ESS 200.

[0030] The analysis unit 100 can set upper and lower limits for SoC-specific output, bank operating range, and cell voltage operating range, and confirm the possible output range before executing the operation plan, and then perform the possible operation output. In addition, the analysis unit 100 can recalculate the output at one-minute intervals to respond sensitively to voltage changes. In this embodiment, the analysis unit 100 can be implemented as, for example, a server, but can be implemented as a variety of devices such as a personal computer, notebook PC, or tablet PC that can perform computing functions and machine learning.

[0031] More specifically, the analysis unit 100 according to an embodiment of the present invention may include an analysis control unit 110, a data acquisition unit 120 for collecting ESS operation records, a data learning unit 130 for deriving an OCV-SoC table based on the ESS operation records, a voltage limit calculation unit 140 for analyzing the OCV-SoC table and calculating stepwise charge / discharge voltage limits, an output limit calculation unit 150 for calculating range-specific output limits for the SoC during charge / discharge according to the calculated voltage limits, and an ESS operation unit 160 for executing ESS charge / discharge commands according to a predetermined SoC range, output / voltage range, and operation plan. The detailed configuration of the analysis unit 100 will be described in more detail in the operation explanation section shown in Figure 2.

[0032] Furthermore, the analysis unit 100 may further include a charge / discharge planning unit 170 and an SoC estimation unit 180 for ESS charge / discharge commands. The charge / discharge operation planning of the charge / discharge planning unit 170 and the SoC estimation operation of the SoC estimation unit 180 can utilize the charge / discharge operation methods of the Artificial Intelligence-Based Predictive ESS Charge / Discharge Operation Apparatus and Method (Korean Registered Patent No. 10-2232513) and the Adaptive SoC Estimation Optimal ESS Operation System and Method (Korean Registered Patent No. 10-2493221). Korean Registered Patent No. 10-2232513 and Korean Registered Patent No. 10-2493221 are incorporated herein by reference.

[0033] On the other hand, the ESS200 may include an ESS control unit 210, a PCS220, a BMS230, and a battery 240. In this case, the ESS control unit 210 can control the PCS220 based on operation plan data or control commands received from the analysis unit 100, and can provide voltage, current, and power data related to ESS operation to the analysis unit 100 or other databases.

[0034] The PCS (Power Conditioning System) 220 is configured to discharge and charge the battery 240 by converting DC power to AC power or DC power. The PCS 220 has safe operating voltage information for the battery 240 that constitutes the ESS 200, or this information can be provided via the analysis unit 100 and the ESS control unit 210. In this case, the safe operating voltage information can be the capacity of the PCS 220 (usually half of the battery) and the corresponding maximum charge output. The ESS control unit 210 can also set the upper and lower limits of the SoC to 10% to 90%, or a similar range, for the safety of the battery.

[0035] On the other hand, the Battery Management System (BMS) 230 is configured to manage each battery 240 and can control the charging and discharging of each battery cell within the battery 240 to prevent situations where only some of the battery cells are overcharged or not charged at all. The BMS 230 can also store ESS operation records at minimum intervals of 1 minute. In this case, the stored ESS operation records may include, for example, battery instantaneous current (A), instantaneous voltage (V), SoC (%), and output (kWh). Here, the ESS operation records may further include power demand (kWh). The ESS operation records are also collected along with time information indicating the time when each data point (battery instantaneous current (A), instantaneous voltage (V), SoC (%), output (kWh), and power demand (kWh)) was collected. ESS operation records are created by the BMS230 by collecting data including battery instantaneous current (A), instantaneous voltage (V), SoC (%), output (kWh), and power demand (kWh) for a predetermined period, along with time information that allows confirmation of the time the data was collected.

[0036] Next, referring to Figures 2 to 13, the detailed configuration and operation of the analysis unit 100, which can set the operation plan for the ESS200 by setting the range of the SoC and determining the output power / voltage upper limit for each SoC range, will be described. In this case, the detailed configuration of the analysis unit 100, which consists of the analysis control unit 110, data acquisition unit 120, data learning unit 130, voltage upper limit calculation unit 140, output upper limit calculation unit 150, and ESS operation unit 160, may be software, software modules, hardware, hardware modules, or a combination of software and hardware.

[0037] The analysis control unit 110 can be implemented, for example, by a processor or by software running on a processor. In this case, the analysis control unit 110 can control the data acquisition unit 120, the data learning unit 130, the voltage upper limit calculation unit 140, the output upper limit calculation unit 150, and the ESS operation unit 160, and manage the overall operation of the analysis unit 100.

[0038] The overall operation of the analysis unit 100 is as shown in Figure 2.

[0039] First, the data collection unit 120, in response to a request from the data learning unit 130, queries, receives, and transmits the breakdown of past operations during a given period from the ESS operation records stored in the BMS 230 or a separate database (S100).

[0040] In this case, data can be collected from the BMS230 or database either by direct database connection or via the Energy Management System (EMS) RestAPI. In this case, the data collection unit 120 collects the instantaneous current (A), instantaneous voltage (V), SoC (%), and output (kWh) of the battery 240 stored in the BMS230, along with a timestamp.

[0041] Next, the data learning unit 130 generates an OCV-SoC table based on the collected ESS operation record data (S200). In this case, the OCV-SoC table can be derived, for example, as described in Korean Registered Patent No. 10-2493221, which is incorporated herein by reference.

[0042] The voltage limit calculation unit 140 can calculate the upper limit of the charge and discharge voltage using the OCV-SoC table, the V-SoC curve during maximum output charging, and the V-SoC table during discharge (S300).

[0043] Specifically, referring to Figures 3 and 4, the voltage upper limit calculation unit 140 can first determine the voltages corresponding to the inflection point SoC1 where the slope of the OCV-SoC curve increases sharply, and the battery safety upper and lower limits of SoC (S310). For example, the battery safety upper and lower limits of SoC can be 90% and 10%, respectively.

[0044] The voltage limit calculation unit 140 then calculates the V-SoC table (voltage-SoC relationship) when the ESS200 is charged at maximum output based on the ESS operation record data, and then calculates the voltage limit during charging (V1~V4) based on the V-SoC table at maximum output charging, the inflection point, and the SoC of the battery safety limit (S320). At this time, the OCV-SoC curve is a value estimated through the open circuit voltage value and may differ from the actual V-SoC curve when the ESS200 is charged at maximum output.

[0045] More specifically, referring to Figure 5, the voltage limit calculation unit 140 can derive the voltage V1 corresponding to the inflection point SoC1 in the V-SoC curve during maximum output charging. The voltage limit calculation unit 140 can also calculate the voltage V4 corresponding to the battery safety limit SoC in addition to V1.

[0046] After calculating V1 and V4, the voltage upper limit calculation unit 140 can, for example, calculate V2 as the midpoint between V1 and the battery safety upper limit SoC voltage (for example, the voltage (V) when the SoC is at 90% in the OCV-SoC curve), and V3 as the midpoint between V2 and V4.

[0047] In this case, the voltage limit calculation unit 140 can generate the V1 to V4 calculated as described above as the voltage limit (V1 to V4) during charging.

[0048] On the other hand, the voltage limit calculation unit 140 calculates the upper limit voltage (V) during discharge based on the V-SoC table at maximum output discharge, the reverse point of the inflection point SoC1, and the battery safety lower limit SoC (for example, 10%). a ~V d ) can be calculated (S330).

[0049] More specifically, referring to Figure 6, the voltage upper limit calculation unit 140 calculates the voltage V corresponding to the inverse point of the aforementioned inflection point SoC1 in the V-SoC curve at maximum output discharge. acan be derived. Here, the reverse point means the difference between 100% and the SoC at that point. For example, the reverse point of the inflection point SoC1 described above means the SoC corresponding to 100 - SoC1.

[0050] Also, the voltage upper limit calculation unit 140 obtains the voltage V corresponding to the SoC of the battery safety lower limit in the OCV - SoC d (for example, the voltage when the SoC is 10% in the OCV - SoC), and again, based on the V in the V - SoC curve during maximum output discharge a and V d the voltage upper limit during discharge can be calculated. For example, V a and V d are divided into three equal parts, and the larger one among the three equal - division points is set as V b , and the smaller one among the three equal - division points is set as V c . After that, the discharge voltage upper limit (V a , V b , V c , V d ) can be calculated.

[0051] Furthermore, referring to FIG. 2, after the charge - discharge voltage upper limit is calculated, the output upper limit calculation unit 150 can calculate and set the charge - discharge output upper limit based on the charge voltage upper limit and the discharge voltage upper limit (S400).

[0052] Specifically, referring to FIG. 7, first, the output upper limit calculation unit 150 can cluster the power - SoC data based on the past ESS operation record data (S410). Referring to FIG. 8, the output upper limit calculation unit 150 separates the power - SoC data during charging based on the past ESS operation record data into five clusters (distinguished by color) based on, for example, the average power value.

[0053] In this case, the cluster with the highest power value (orange color) among the clusters is the power - SoC data during charging at the maximum output power, which corresponds to the V - SoC curve during maximum output charging obtained previously. When charging at the maximum output, there is no need to obtain a separate output upper limit.

[0054] On the other hand, the output limit calculation unit 150 can derive SoC intervals (SoC1 to SoC4) based on the V-SoC of each cluster and the voltage limit during charging (S420).

[0055] Specifically, the output limit calculation unit 150 can calculate a V-SoC table like the one in Figure 9 using the data corresponding to the cluster with the second highest power value (purple) within the cluster. At this time, the SoC (SoC2) corresponding to the charging power limit (V2) can be determined. Furthermore, the output limit calculation unit 150 can calculate a V-SoC like the one in Figure 10 using the data corresponding to the cluster with the third highest power value (red) within the cluster, and at this time, the SoC (SoC3) corresponding to the charging power limit (V3) can be determined. After calculating the V-SoC using the data corresponding to the fourth highest cluster (green) in the same way, the output limit calculation unit 150 can determine the SoC (SoC4) corresponding to V4. In other words, the maximum SoC (SoC2~SoC4) that does not exceed V2, V3, and V4 can be calculated based on the V-SoC curves of the top three outputs excluding the maximum power. In this way, for example, the SoC interval during charging as shown in Figure 11 can be derived.

[0056] Then, the output limit calculation unit 150 derives the output limit for each SoC section during charging (S430).

[0057] More specifically, during charging, the ESS200's maximum output is limited to the power limit in the section (1) containing an SoC smaller than SoC1. In the section (2) between SoC1 and SoC2, the output limit is set to the power value corresponding to the cluster with the second highest power value (for example, 80kWh in Figure 6). In the section between SoC2 and SoC3, the output limit can be set to the power value corresponding to the cluster with the second highest power value (for example, 60kWh in Figure 6).

[0058] However, if the SoC is above a certain threshold, for example, 80% or more, the output limit can be set to a value determined for battery safety. For example, for SoCs above 80%, the output limit can be fixed to (maximum power) / 5 in the 80% to 85% range and to maximum power / 10 in the 85% to 90% range for battery safety.

[0059] On the other hand, if the SoC value (SoC4), which is the reference for the last interval in the aforementioned intervals, does not reach 80%, the output limit calculation unit 150 can determine the output value determined from the SoC value (SoC4), which is the reference for the last interval, as the output limit. For example, in Figure 11, the power can be controlled to (maximum power) / 5 in the interval (4) where the power exceeds 80%, but in the example in Figure 12, since SoC4 does not exceed 80%, the power can be controlled to charge SoC4 to (maximum power) / 5.

[0060] Therefore, the output limit calculation unit 150 can generate the maximum SoC value (SoC1 to SoC4) for each section and the charging output limit value corresponding to each section.

[0061] Then, during discharge, the upper limit of the output for each SoC section is derived based on the inverse point of the maximum SoC value for each section during charging (S440).

[0062] During the discharge process, the same method as during the charging process (i.e., clustering using power-SoC data) cannot be applied for the following reasons.

[0063] 1) The charging process must proceed quickly during periods of light load, but the discharging process is generally carried out based on calculations that take electricity costs into consideration.

[0064] 2) The price variable is an arbitrarily fluctuating value, making it difficult to clearly estimate and apply an upper limit to the output through existing ESS operational data.

[0065] Therefore, during charging, the lower limit of the discharge SoC is derived based on the inverse point of the maximum SoC value (SoC1 to SoC4) for each section, and then the possible upper limit of the output is calculated. At this time, the output upper limit calculation unit 150 calculates the upper limit of the voltage (V a ~V d The output limit can be determined based on this.

[0066] First, the output limit calculation unit 150 sets the discharge output limit at maximum power in the section (6) up to the reverse point of SoC1 (100-SoC1), in the opposite direction to charging. At this time, the reverse point (100-SoC4~100-SoC1) of the maximum SoC values ​​(SoC1~SoC4) for each charging section obtained in the charging process described above can be determined, and the discharge SoC section can be set as shown in Figure 13.

[0067] In this case, the output upper limit calculation unit 150 calculates the voltage range (V) during discharge specified for each section. a ~V d Select a maximum output that does not exceed ). For example, during discharge, SoC sections (7), (8), and (9) are V b , V c , V d A maximum output that does not exceed can be selected. More specifically, among the discharge data corresponding to the SoC section (7), V b You can select data that does not exceed and choose the one with the highest output within that data as the upper limit of the discharge output. Alternatively, within the discharge data corresponding to the SoC section (8), V c You can select data that does not exceed and choose the one with the highest output within that data as the upper limit of the discharge output. Alternatively, among the discharge data corresponding to the SoC section (9), V d By selecting data that does not exceed a certain threshold, the upper limit of the discharge output can be determined by selecting the data with the highest output among those selected.

[0068] Using the method described above, the output limit calculation unit 150 can generate upper limits for both charging output and discharging output.

[0069] Finally, the ESS operation unit 160 can perform charging and discharging by transmitting control commands to the PCS 220 via the ESS control unit 210 according to the charge / discharge amount and charge / discharge time planned by the charge / discharge planning unit 170 (S500).

[0070] However, the ESS operation unit 160 according to the embodiment of the present invention basically generates control commands to operate the ESS according to the charge / discharge operation plan of the charge / discharge planning unit 170, and operates with the following priority order in order to take into consideration the maintenance of the ESS's safe operating voltage and minimum base power.

[0071] Priority 1: If the current instantaneous voltage value falls outside the ESS's safe operating voltage range, ignore the charge / discharge plan and interrupt the charge / discharge process.

[0072] Priority 2: If the current power collected through the data acquisition unit 120 falls below the minimum base power, the charge / discharge plan is ignored, and a discharge command is executed to bring the power up to the minimum base power. If there is no remaining battery power, the charge / discharge process is interrupted.

[0073] Priority 3: The charge / discharge command is executed according to the charge / discharge plan set by the charge / discharge planning unit 170, and the charge / discharge is interrupted if the battery level is insufficient or fully charged, according to the SoC estimated by the SoC estimation unit 180.

[0074] Priority 4: The ESS operation unit 160 generates an operation output control command based on the SoC-specific output limit calculated by the output limit calculation unit 150 during ESS operation.

[0075] When the ESS was operated with SoC-specific output limits set according to the present invention, the failure rate decreased and the operating rate increased by more than 20p compared to the existing operating method. When operating the ESS according to the present invention, the operating rate of the existing operating method was 76.8% compared to the same period, while the operating rate after applying the method of the present invention was 98.2%, and the ESS could be used even more efficiently by operating with an optimized schedule.

[0076] Furthermore, after excluding the variability caused by the difference between predicted and actual solar radiation, the ESS could be used very efficiently, almost exactly as planned. As can be seen in Figure 14, before the application of the present invention, the output limit was not properly set, and it was not possible to operate as planned.

[0077] In particular, in section 1200, it can be seen that there is a very large difference between the purple block in Figure 14 of the operation plan and the yellow line representing the actual operation data. This suggests that the output limit was not properly set, making it impossible to operate according to the plan.

[0078] However, referring to Figure 15, we can see how the ESS is operated in a manner that is even more similar to the ESS operation plan after applying the method according to the embodiment of the present invention. Specifically, in section 1300 of Figure 15, which corresponds to section 1200, it can be seen that the difference between the purple block of the operation plan and the yellow line, which is the actual operation data, is very small, and that the difference occurred only in sections where variability caused by the difference between the predicted solar radiation value and the actual solar radiation occurred.

[0079] Therefore, according to the present invention, an ESS charging and discharging system can be provided that calculates in advance the maximum output that can be driven by the SoC during the charging and discharging process, and uses the ESS most efficiently within a range that does not induce battery safety problems.

[0080] Although embodiments of the present invention have been described in more detail above with reference to the attached drawings, the present invention is not necessarily limited to these embodiments and can be modified and implemented in various ways without departing from the technical concept of the present invention. Therefore, the embodiments disclosed herein are not intended to limit the technical concept of the present invention, but merely to illustrate it, and the scope of the technical concept of the present invention is not limited by these embodiments. Accordingly, the embodiments described above should be understood to be illustrative and not restrictive in all respects. The scope of protection of the present invention should be interpreted in accordance with the following claims, and all technical concepts belonging to an equivalent scope should be interpreted as being included in the scope of rights of the present invention. [Explanation of Symbols]

[0081] 100 Analysis Unit 110 Analysis Control Unit 120 Data acquisition unit 130 Data learning unit 140 Voltage upper limit calculation unit 150 Output upper limit calculation unit 160 ESS Operation Department 170 Charge / Discharge Planning Department 180 SoC estimation section 200 ESS

Claims

1. A data acquisition unit for collecting ESS operation record data, comprising at least: first Soc data including each of a plurality of time periods, a plurality of open-circuit battery voltages corresponding to that time period, and a plurality of SoCs corresponding to that time period; second Soc data including each of a plurality of time periods, a plurality of charging battery voltages corresponding to that time period, and a plurality of SoCs corresponding to that time period; and third Soc data including each of a plurality of time periods, a plurality of discharging battery voltages corresponding to that time period, and a plurality of SoCs corresponding to that time period. A data learning unit generates an OCV-SoC table, a V-SoC table during charging, and a V-SoC table during discharging, respectively, based on the aforementioned ESS operation record data. A voltage limit calculation unit calculates the upper limit of the voltage during charging based on at least one of the inflection points or battery safety upper limit SoC values ​​calculated based on the OCV-SoC table and the charging V-SoC table, and calculates the upper limit of the voltage during discharge based on the discharge V-SoC table and at least one of the battery safety lower limit SoC value calculated based on the OCV-SoC table or the inverse point of the inflection point. An output limit calculation unit calculates the range of SoC for charging and discharging according to the calculated voltage limit, and calculates an output limit according to the calculated range of SoC for charging and discharging, An ESS operation unit that executes ESS charge / discharge commands based on the range of SoC for charging and discharging, and the output upper limit corresponding to the calculated range of SoC for charging and discharging, An ESS charge / discharge control system, including the above.

2. The ESS charge / discharge control system according to claim 1, wherein the output limit calculation unit clusters power-SoC data based on ESS operation record data, derives SoC intervals during charging based on at least a portion of the V-SoC tables and the voltage limit during charging of the clustered clusters, and derives output limits for each SoC interval during charging.

3. The ESS charge / discharge control system according to claim 2, wherein the output limit calculation unit derives the SoC interval during discharge based on the inverse point of the SoC which is the maximum value of the SoC interval during charging, and derives the output limit for each SoC interval during discharge.

4. It further includes a charge / discharge planning unit, The ESS charge / discharge control system according to claim 1, wherein the ESS operation unit transmits control commands to the ESS according to the planned charge / discharge amount and charge / discharge time to perform charging and discharging.

5. A step in which a data acquisition unit collects ESS operation record data comprising: first Soc data including each of a plurality of time periods, a plurality of open-circuit battery voltages corresponding to that time period, and a plurality of SoCs corresponding to that time period; second Soc data including each of a plurality of time periods, a plurality of charging battery voltages corresponding to that time period, and a plurality of SoCs corresponding to that time period; and a plurality of third Soc data including each of a plurality of time periods, a plurality of discharging battery voltages corresponding to that time period, and a plurality of SoCs corresponding to that time period; The data learning unit generates an OCV-SoC table, a V-SoC table during charging, and a V-SoC table during discharging, respectively, based on the ESS operation record data. A step of calculating the voltage limit during charging based on the voltage limit calculation unit, which calculates at least one of the inflection points or battery safety limit SoC values ​​calculated based on the OCV-SoC table, and the charging V-SoC table, A step of calculating the upper voltage limit during discharge based on the V-SoC table during discharge and at least one of the following: the lower limit of battery safety SoC value calculated based on the OCV-SoC table or the inverse point of the inflection point. The output limit calculation unit calculates the range of SoC for charging and discharging according to the upper limit of the charge and discharge voltage, and calculates the output limit according to the calculated range of SoC for charging and discharging. The ESS operation unit generates an ESS charge / discharge command based on the range of the charge and discharge SoC and the calculated output upper limit corresponding to the range of the charge and discharge SoC, An ESS charge / discharge control method, including the above.

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