Energy storage system including newly installed battery rack and method for controlling same

Abstract

To provide an energy storage system comprising an existing battery rack and a new installation battery rack.SOLUTION: An energy storage system according to an embodiment of the present invention may comprise: a plurality of first battery racks; a plurality of battery protective units for managing the plurality of first battery racks, respectively; a plurality of second battery racks; a plurality of DC / DC converters for managing the plurality of second battery racks, respectively; and a battery section control device which is linked to the plurality of battery protective units and the plurality of DC / DC converters so as to monitor output of the plurality of DC / DC converters and the plurality of battery protective units, and which controls the output of the plurality of DC / DC converters.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2021-0119406, filed with the Korean Intellectual Property Office on September 8, 2021, and all of the contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to an energy storage system and a method for controlling an energy storage system, and more particularly to an energy storage system including a new or later-installed battery rack and a method for controlling an energy storage system. [Background technology]

[0003] An energy storage system (ESS) is a system that connects renewable energy sources, batteries that store power, and existing power grids. In recent years, smart grids and renewable energy sources have become more widespread, and as the efficiency and stability of power grids have become more important, the demand for energy storage systems is increasing to regulate power supply and demand and improve power quality. Depending on the purpose of use, the output and capacity of energy storage systems vary, and multiple battery systems can be connected to form a large-capacity energy storage system.

[0004] In an energy storage system, the performance of some battery racks may decline over time, and new battery racks may be added to existing battery racks to compensate for this. In this case, there may be a difference in performance between the newly added racks and the existing racks, and this difference in performance between the racks may lead to unnecessary repeated rack balancing. This can cause a problem where the new battery racks, even though they were added to compensate for the performance, end up matching the performance of the existing racks. In other words, even though new battery racks are added, the maximum performance (e.g., rated capacity, usage period, etc.) of the new battery racks cannot be fully utilized. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Korean Patent Publication No. 10-2016-0094228 Summary of the Invention [Problem to be solved by the invention]

[0006] SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide an energy storage system including an existing battery rack and a new battery rack.

[0007] Another object of the present invention to solve the above problems is to provide a device for controlling a battery system including an existing battery rack and a new battery rack.

[0008] Another object of the present invention to solve the above problems is to provide a method for controlling an energy storage system including an existing battery rack and a new battery rack. [Means for solving the problem]

[0009] To achieve the above object, one embodiment of the present invention provides an energy storage system that includes a plurality of first battery racks; a plurality of battery protection units that manage the plurality of first battery racks, respectively; a plurality of second battery racks; a plurality of DC / DC converters that manage the plurality of second battery racks, respectively; and a battery section control device that works in conjunction with the plurality of battery protection units and the plurality of DC / DC converters to monitor the outputs of the plurality of battery protection units and the plurality of DC / DC converters and control the outputs of the plurality of DC / DC converters.

[0010] The battery section control device can detect the output power values ​​of the multiple first battery racks that operate in accordance with the charge or discharge commands of the energy storage system, and calculate the output power values ​​output by the multiple second battery racks using the output power values ​​of the multiple first battery racks, information on the multiple first battery racks, and information on the multiple second battery racks.

[0011] The information on the plurality of second battery racks may include one or more of the number of the plurality of second battery racks, SOH, SOC, output current, output power, and temperature.

[0012] The battery section controller can calculate a power weight value for each second battery rack using information about the plurality of second battery racks.

[0013] The battery section control device can also calculate a power command value for each of the second battery racks based on the output weight value of the second battery rack and the number of the second battery racks relative to the total number of battery racks in the energy storage system.

[0014] The battery section control device can interrupt the outputs of the plurality of DC / DC converters when the output of a PCS (Power Conversion System) indicates the stop of charging / discharging operations.

[0015] The charge or discharge command can be transmitted from an EMS (Energy Management System) to a PCS.

[0016] To achieve the above-mentioned other object, a battery system control device according to one embodiment of the present invention can be linked with a plurality of battery protection units that respectively manage a plurality of first battery racks and a plurality of DC / DC converters that respectively manage a plurality of second battery racks, and includes at least one processor; and a memory that stores at least one instruction to be executed through the at least one processor.

[0017] The at least one instruction may include an instruction to monitor outputs of the plurality of battery protection units and the plurality of DC / DC converters; and an instruction to control outputs of the plurality of DC / DC converters according to the results of the monitoring.

[0018] The instructions for monitoring the outputs of the plurality of battery protection units and the plurality of DC / DC converters may include instructions for detecting the output power values ​​of the plurality of first battery racks that operate in accordance with a charge or discharge command of the energy storage system.

[0019] The instruction to control the output of the plurality of DC / DC converters according to the results of the monitoring may include an instruction to calculate the output power value output by the plurality of second battery racks using the output power values ​​of the plurality of first battery racks, information about the plurality of first battery racks, and information about the plurality of second battery racks.

[0020] The instructions for controlling the outputs of the plurality of DC / DC converters according to the results of the monitoring may include instructions for calculating an output weighted value of each second battery rack using information about the plurality of second battery racks; and instructions for calculating a power command value for each second battery rack based on the output weighted value of the second battery rack and the number of the second battery racks relative to the total number of battery racks in the energy storage system.

[0021] The charge or discharge command can be transmitted from an EMS (Energy Management System) to a PCS.

[0022] In order to achieve the above-mentioned yet another object, a control method for an energy storage system according to one embodiment of the present invention is a control method for an energy storage system including a plurality of first battery racks, a plurality of battery protection units that respectively manage the plurality of first battery racks, a plurality of second battery racks, and a plurality of DC / DC converters that respectively manage the plurality of second battery racks, and includes the steps of monitoring the outputs of the plurality of battery protection units and the plurality of DC / DC converters; detecting the output power values ​​of the plurality of first battery racks that operate in accordance with a charge or discharge command of the energy storage system; calculating the output power values ​​output by the plurality of second battery racks using the output power values ​​of the plurality of first battery racks, information about the plurality of first battery racks, and information about the plurality of second battery racks; and controlling the output of the plurality of DC / DC converters according to the calculated output power values.

[0023] The step of calculating the output power values ​​output by the plurality of second battery racks may include the steps of: calculating an output weight value of each second battery rack using information about the plurality of second battery racks; and calculating a power command value for each second battery rack based on the output weight value of the second battery rack and the number of the second battery racks relative to the total number of battery racks in the energy storage system.

[0024] The information on the plurality of second battery racks may include one or more of the number of the plurality of second battery racks, SOH, SOC, output current, output power, and temperature.

[0025] The method for controlling the energy storage system may include a step of interrupting the outputs of the plurality of DC / DC converters when an output of a power conversion system (PCS) indicates a stop of charging / discharging operations.

[0026] The charge or discharge command can be transmitted from an EMS (Energy Management System) to a PCS. [Effects of the Invention]

[0027] According to the above-described embodiments of the present invention, when a new battery rack is added to an energy storage system, unnecessary or excessive rack balancing can be prevented or reduced.

[0028] This allows the performance of the new battery rack to be utilized to the maximum (for example, 100%).

[0029] Furthermore, the present invention allows the system to operate in the same way as the existing method by only modifying the firmware of the BSC without modifying the firmware of the PCS and PMS. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a block diagram of an existing energy storage system. [Figure 2] FIG. 1 is a block diagram of an energy storage system according to an embodiment of the present invention. [Figure 3] 10 shows the relationship between the output command value and the output value in each battery region when starting and stopping the energy storage system according to an embodiment of the present invention. [Figure 4]1 illustrates a concept for calculating the output control weights of each DC / DC converter in an augmentation region according to an embodiment of the present invention. [Figure 5] FIG. 2 is a flow chart of a control method for an energy storage system according to an embodiment of the present invention. [Figure 6] 1 is a schematic block diagram of a battery system control device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, it is understood that this is not intended to limit the present invention to the specific embodiments, but rather to include all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention. Like reference numerals are used to refer to like elements throughout the drawings.

[0032] Terms such as "first," "second," "A," and "B" may be used to describe various components, but the components should not be limited by these terms. These terms are used only to distinguish one component from another. For example, a first component may be termed a "second component," and similarly, a second component may be termed a "first component," without departing from the scope of the present invention. The term "and / or" includes a combination of multiple associated listed items or any of multiple associated listed items.

[0033] When a component is said to be "coupled" or "connected" to another component, it is understood that the component may be directly coupled or connected to the other component, but that there may be other components in between. In contrast, when a component is said to be "directly coupled" or "directly connected" to another component, it is understood that there are no other components in between.

[0034] The terms used in this application are merely used to describe specific embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly indicates otherwise. It should be understood that in this application, the terms "comprise" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and do not preclude the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0035] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted as having an ideal or overly formal meaning unless expressly defined in this application.

[0036] Some terms used in this specification are defined as follows:

[0037] SOC (State of Charge) is the current charged state of the battery expressed as a percentage [%], and SOH (State of Health) is the current remaining state of the battery expressed as a percentage [%].

[0038] A battery rack is a system with the smallest single structure that can be monitored and controlled through a BMS by connecting modules set by the battery manufacturer in series or parallel, and can be composed of multiple battery modules and one BPU or protection device.

[0039] A battery bank can refer to a large-scale collection of battery rack systems consisting of multiple racks connected in parallel. The battery bank BMS can monitor and control the rack BMS (RBMS) for each battery rack.

[0040] A BSC (Battery System Controller) is a device that performs top-level control for a battery system including a battery system in units of a battery bank, and can also be used as a control device in a battery system with a multi-bank level structure.

[0041] Nominal Capacity (Nominal Capa.) can refer to the battery's set capacity [Ah] set by the battery manufacturer at the time of development.

[0042] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0043] FIG. 1 is a block diagram of an existing energy storage system.

[0044] The smallest unit of a battery that stores power in an energy storage system (ESS) is typically a battery cell. A series / parallel combination of battery cells forms a battery module, and a number of battery modules can form a battery rack. In other words, a battery rack is a series / parallel combination of battery modules and can be the smallest unit of a battery system. Here, a battery rack can also be called a battery pack depending on the device or system in which the battery is used.

[0045] Referring to Figure 1, one battery rack can include multiple battery modules and one BPU 10 or protection device. The battery rack can be monitored and controlled through an RBMS (Rack BMS). The RBMS monitors the current, voltage, and temperature of each battery rack under its control, calculates the battery's SOC (Status Of Charge) based on the monitoring results, and controls charging and discharging.

[0046] Meanwhile, the BPU (Battery Protection Unit) 10 is a device for protecting batteries from abnormal current and fault current in each battery rack. The BPU 10 can include a main contactor (MC), fuses, circuit breakers (CB), or disconnect switches (DS). The BPU can control the battery system in each rack by controlling the on / off of the main contactors through the control of the RBMS. The BPU can also protect the batteries from short-circuit current using fuses when a short circuit occurs. In this way, existing battery systems can be controlled through protection devices such as the BPU and switchgear.

[0047] Meanwhile, a battery section controller (BSC) 20 is provided in each battery section, which includes a number of batteries and peripheral circuits and devices, and is capable of monitoring and controlling control targets such as voltage, current, temperature, and circuit breakers. The BSC 20 is the highest-level controller of a battery system including a bank-based battery system including a number of battery packs, and may also be used as a controller in a battery system with a multi-bank structure.

[0048] In addition, a power conversion system (PCS) 40 provided for each battery section is a device that actually charges and discharges based on a charge / discharge command from the EMS, and can be configured to include a power conversion unit (DC / AC inverter) and a controller. Meanwhile, the output of each BPU can be connected to the PCS 40 via a DC bus, and the PCS 40 can be connected to the grid. In addition, the EMS (Energy Management System) / PMS (Power Management System) 30 manages the ESS system as a whole.

[0049] In a conventional battery system as shown in Figure 1, the battery system is controlled only through protection elements such as BPU and switch gear, and individual control taking into account the individual characteristics of the battery system such as battery capacity, SOH, and SOC is not possible.

[0050] In such energy storage systems, multiple battery racks act as voltage sources, and the PCS charges and discharges the battery racks through CC (Constant Current) control or CP (Constant Power) control. When the battery racks are initially installed, their performance is almost similar (when expressed as equivalent resistance, they have similar resistance values), and the charge and discharge current of each rack is at a similar level. However, over time, the performance of some racks may deteriorate. In this case, new battery racks are added to compensate for the performance, which is called augmentation.

[0051] In this case, there may be a performance difference between the newly added battery rack (which may be referred to as a second battery rack) and the previously installed battery rack (which may be referred to as a first battery rack). Therefore, with existing control methods, unnecessary or excessive rack balancing may be repeated, resulting in a problem in which the newly added battery rack follows the degraded performance of the previously installed battery rack. That is, even though the battery rack is newly added, the maximum performance (e.g., rated capacity, service life, etc.) of the new battery rack may not be fully utilized. In embodiments of the present invention, the new battery rack may include a newly manufactured battery rack, but may also include a battery rack used to reinforce an existing battery rack at a later point in time, including a DC / DC converter for DC / DC conversion, or may be a previously used or refurbished battery rack.

[0052] FIG. 2 is a block diagram of an energy storage system according to an embodiment of the present invention.

[0053] 2 illustrates a system in which multiple new battery racks are added to an existing energy storage system. According to an embodiment of the present invention, the existing energy storage system may include similar features to the energy storage system illustrated in FIG. 1. The existing energy storage system may include the EMS 300, PCS 400, BPU 100, battery rack (old rack), and BSC 200 as described with reference to FIG. 1. The EMS (Energy Management System), also known as the PMS (Power Management System), manages the ESS system as a whole.

[0054] The BSC (Battery Section Controller) 200 manages the status of each rack and notifies the upper system (EMS) of the limit value of the battery that can be output. The BSC 200 can be implemented as a device mounted on a desktop PC or the like. The BSC 200 can also be implemented as a separate device or controller. The PCS 400 is a device that actually charges and discharges based on a charge / discharge command received from the EMS 300, and can include a DC / AC power converter and a controller.

[0055] On the other hand, if augmentation is performed in which a new battery rack is added to reinforce the existing battery rack in addition to the multiple battery racks and BPUs that are currently in operation, i.e., if the existing battery rack and the new battery rack coexist due to augmentation, the performance of the new battery rack may rapidly deteriorate or problems such as imbalances in the balancing between the racks may occur if the existing control method is used.

[0056] Therefore, an energy storage system according to one embodiment of the present invention uses a DC / DC converter (in the augmentation area) instead of a BPU for newly added battery racks, thereby reducing or preventing problems such as a sudden drop in performance of the newly added battery racks and imbalances in balancing between racks.

[0057] The DC / DC converter 150 can include a main body and a DC / DC controller. The DC / DC converter 150 performs DC / DC conversion between a battery and a power conversion system (PCS).

[0058] The DC / DC converter placed in the augmentation area allows the existing battery rack and the new battery rack to be electrically separated and operated. The DC / DC converter output can be actively controlled by the user, and even if there are differences in SOC, SOH, and capacity between the battery racks, it is possible to control the battery output taking into account the characteristics of each battery rack.

[0059] Each DC / DC converter is connected to the BSC 200 and the PCS 400. The BSC 200 can monitor and manage the status of not only the battery racks placed in the existing area but also the battery racks placed in the augmentation area.

[0060] On the other hand, from the perspective of end users who use the services provided by the energy storage system, an important issue is whether the battery can be operated without changing the PCS and EMS that they are currently using.

[0061] The present invention provides an augmentation method using a DC / DC converter, which requires only modification of the BSC firmware in the battery area, without modifying the firmware of the PCS and EMS.

[0062] In an embodiment of the present invention, new battery racks (New Racks) in the augmentation area are used to strengthen existing battery racks (Old Racks) and include a DC / DC converter 150 instead of a BPU 100. Therefore, using a DC / DC converter 150 dedicated to the newly added battery rack (New Rack) in the augmentation area instead of a battery protection unit (BPU) can provide the advantage of avoiding or reducing rapid deterioration of the newly added battery rack or balancing. In addition, it can provide the advantage of only modifying the firmware of the BSC in the battery area without modifying the firmware of the PCS or EMS.

[0063] First, the startup sequence of the energy storage system according to the present invention will be described.

[0064] Referring to FIG. 2, the EMS 300 issues a charge / discharge command (P bat * ) and transmits the charge / discharge command (P bat * ) and outputs the power corresponding to the command. At this time, the BPU racks located in the existing area are given priority (temporarily) to receive the P bat * power is output.

[0065] Here, the BSC 200 is in a state where it knows the quantity information of the BPU racks arranged in the existing area and the DC / DC racks (used as a concept including battery racks and DC / DC converters) arranged in the augmentation area. The BSC 200 calculates the total output value (P bat * ) is monitored. Therefore, P bat * means the total output power required for the BPU rack in the existing area and the DC / DC rack in the augmentation area.

[0066] On the other hand, the BSC 200 calculates the value P of the new battery rack in the augmentation area based on at least the value output by the battery rack in the existing area, the quantity information of the battery rack in the existing area, and the quantity information of the battery rack in the augmentation area. aug * Calculate.

[0067] The BSC 200 also calculates the output weight value for each battery rack in the augmentation area based on the state information (SOC, SOH, etc.) of each battery rack located in the augmentation area. aug *The output value of each DC / DC rack can be calculated by multiplying the power consumption by the power consumption of the DC / DC rack in the augmentation area with respect to the BPU rack in the existing area. That is, the BSC 200 calculates the charge / discharge command for the DC / DC converter by taking into account the remaining energy of the DC / DC rack in the augmentation area relative to the BPU rack in the existing area. The calculated charge / discharge command for the DC / DC converter is transmitted to each DC / DC converter via the communication line 250, and the DC / DC rack receives the P aug * Outputs the power of the value.

[0068] In an embodiment of the present invention, the output power (P bat * ) is the charge / discharge command for the output power (P bat * In this regard, the charge / discharge command for the output power is a directive for the output power (P bat * ) is the output power (P bat * ) can be expressed or symbolized as a value of P bat * can be used to express the charge / discharge command and output power depending on the situation. Similarly, the output value P aug * The charge / discharge command for aug * In this regard, the charge / discharge command for the output value P aug * The output value P required or requested by the charge / discharge command aug * can be expressed or symbolized by the value of P aug * can be used to specify charge / discharge commands and output values ​​depending on the context.

[0069] The above-described series of steps in the startup sequence are carried out within a very short time after the PCS output starts.

[0070] Next, the shutdown sequence of the energy storage system will be described.

[0071] When the system is stopped, the output of the PCS400 becomes 0. In this case, the existing BPU area is a passive element area, so the output of the battery rack changes depending on the output of the PCS. However, the DC / DC area, which is an augmentation area, operates under the command of the BSC, so the output P aug * That is, for a very short moment, the augmentation region holds P aug * During this time, the BSC detects that the output to the PCS has become 0, and the output command value P aug * is corrected to 0. Through this process, the output of all racks in the BPU area and DC / DC area becomes 0, causing the system to stop operating.

[0072] FIG. 3 shows the relationship between the output command value and the output value in each battery region when starting and stopping the energy storage system according to the embodiment of the present invention.

[0073] In the startup sequence, the EMS issues a charge / discharge command (P bat * ) is received from the battery in the existing area through the PCS. bat * When the power of P is output, the BSC bat * and the battery rack in the augmentation area outputs the value P aug * is calculated and transmitted to the augmentation region.

[0074] The augmentation region is P aug * At the time of outputting the value of (P bat * -P aug *) power is output. At this time, the command value of the PCS is P bat * However, regardless of whether the EMS is augmented or not, the command value P bat * In this way, according to the present invention, the PCS and EMS can operate in the same way as existing systems, regardless of whether or not augmentation is performed.

[0075] On the other hand, in the shutdown sequence, the PCS command value becomes 0 when the system is shut down. In this case, the existing BPU area is a passive element area, so the output of the battery rack changes depending on the output of the PCS. The DC / DC area, which is the augmentation area, has an output P aug * The output is controlled to 0 when a stop command is received from the BSC. aug * The BPU area temporarily accepts the output for a short time (-P aug * ) When the output of the DC / DC domain becomes 0 due to a stop command from the BSC, the output of the BPU domain also becomes 0.

[0076] FIG. 4 illustrates a concept for calculating the output control weights of each DC / DC converter in the augmentation region according to an embodiment of the present invention.

[0077] According to an embodiment of the present invention, the BSC can estimate the state of each battery rack based on information such as SOC and SHO of the battery racks arranged in the augmentation area, and calculate the output weight value of each DC / DC rack based on this value.

[0078] 4, the BSC 200 receives data such as the SOC, SOH, current, voltage, and temperature of each battery rack from each DC / DC rack. The BSC uses this information to calculate the output weights α2, ...α n can be calculated.

[0079] The following formula 1 is the total output command value P for the augmentation region. aug * In the embodiment of the present invention, the formula for calculating P bat * , P aug * The unit of may be watts (W).

[0080]

number

[0081] In Equation 1, m is the number or quantity of BPU racks, and n is the number (or quantity) of DC / DC racks. bat * is the charge / discharge command value received from the EMS.

[0082] Equation 2 is the output command value P of the DC / DC rack in the augmentation region. DC / DC-1 * ~P DC / DC-n * The formula for calculating is shown below.

[0083]

number

[0084] In Equation 2, the output command value of the DC / DC rack is the total output command value P aug * It can be seen that it is calculated by multiplying the output weight of each rack by the weight of each rack. Also, the sum of the output weight of each DC / DC rack is 1.

[0085] In one embodiment, the battery racks within the augmentation area are assumed to be homogenous battery racks.

[0086] If the batteries in the augmentation area are of the same type and have similar SOH, the output weight value α of battery rack #j during charging jcan be expressed as the following Equation 3.

[0087]

number

[0088] In addition, when the batteries in the augmentation region are of the same type and have similar SOH, the output weighting value for each rack during discharge can be determined as the ratio of the SOC of the corresponding rack to the SOC of all battery racks in the augmentation region, which can be defined as Equation 4 below.

[0089]

number

[0090] On the other hand, if the battery models are the same but the battery racks have different SOHs, the output weight value for each battery rack can be determined taking into account not only the SOC of each rack but also the SOH.

[0091] For example, the output weight value for each battery rack during charging can be defined as Equation 5 below.

[0092]

number

[0093] In addition, the output weight value for each battery rack during discharge can be defined as Equation 6 below.

[0094]

number

[0095] In the above Equations 3 to 6, n, i, and j are integers. Therefore, the output weight value of the new battery rack #j can provide the amount of augmented power that each new battery rack #j must supply, and the output weight value can be included in the charge / discharge command.

[0096] FIG. 5 is a flow chart of a control method for an energy storage system according to an embodiment of the present invention.

[0097] The energy storage system control method of the present invention can be performed by a battery section control device in an energy storage system including a plurality of first battery racks, a plurality of battery protection units that respectively manage the plurality of first battery racks, a plurality of second battery racks, and a plurality of DC / DC converters that respectively manage the plurality of second battery racks.

[0098] The battery section control device monitors the outputs of the plurality of battery protection units and the plurality of DC / DC converters (S510).

[0099] The battery section control device detects the output power values ​​of the plurality of first battery racks that operate according to the charge or discharge command of the energy storage system (S520).

[0100] Then, the battery section control device calculates output power values ​​output by the plurality of second battery racks (S530). Here, the output power values ​​output by the second battery racks may be calculated using the output power values ​​of the plurality of first battery racks, information about the plurality of first battery racks, and information about the plurality of second battery racks. More specifically, the step of calculating the output power values ​​output by the plurality of second battery racks may include calculating an output weight value for each second battery rack using information about the plurality of second battery racks, and calculating a power command value for each second battery rack based on the output weight value of the second battery rack and the number of the second battery racks relative to the total number of battery racks in the energy storage system. Here, the information about the plurality of second battery racks may include one or more of the number of the plurality of second battery racks, SOH, SOC, output current, output power, and temperature.

[0101] Thereafter, the outputs of the DC / DC converters can be controlled according to the calculated output power value (S540).

[0102] FIG. 6 is a schematic block diagram of a battery system control device according to an embodiment of the present invention.

[0103] The battery system controller (or battery section controller) 200 may include at least one processor; and a memory that stores at least one instruction executed via the at least one processor.

[0104] The at least one instruction may include an instruction to monitor outputs of the plurality of battery protection units and the plurality of DC / DC converters; and an instruction to control outputs of the plurality of DC / DC converters according to the results of the monitoring.

[0105] The processor may execute program commands stored in at least one memory. The processor may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which the method according to the embodiment of the present invention is performed. The memory may be composed of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory may be composed of at least one of a read-only memory (ROM) and a random access memory (RAM).

[0106] The operations of the methods according to the embodiments of the present invention may be embodied as a computer-readable program or code on a computer-readable recording medium. The computer-readable recording medium includes all types of storage devices in which data readable by a computer system is stored. The computer-readable recording medium may also be distributed among computer systems connected via a network, so that the computer-readable program or code can be stored and executed in a distributed manner. The computer-readable recording medium may also include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. The program instructions may include not only machine language code, such as that produced by a compiler, but also high-level language code that can be executed by a computer using an interpreter, etc.

[0107] Some aspects of the invention have been described in the context of an apparatus, but they may also be described in terms of a corresponding method, where a block or apparatus corresponds to a method step or feature of a method step. Similarly, aspects described in the context of a method may be described in terms of a corresponding block or item or feature of a corresponding apparatus. Some or all of the method steps may be performed by (or using) a hardware apparatus, such as a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most important method steps may be performed by such an apparatus.

[0108] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will understand that various modifications and variations can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the following claims.

Claims

1. One or more first battery racks; one or more second battery racks; one or more DC / DC converters each controlling one of the second battery racks; and a battery system control device that monitors outputs of the first battery rack and the DC / DC converter in conjunction with the first battery rack and the DC / DC converter and controls the output of the DC / DC converter; Including, the first battery rack is not directly connected to the DC / DC converter, and output control according to the state of the first battery rack is not possible; An energy storage system in which the battery system control device uses the DC / DC converter to control the output of the second battery rack so that the second battery rack reinforces the performance of the first battery rack.

2. The battery system control device Detecting an output power value of the first battery rack that operates according to a charge or discharge command of the energy storage system; The energy storage system according to claim 1 , wherein an output power value output by the second battery rack is calculated using the output power value of the first battery rack, information about the first battery rack, and information about the second battery rack.

3. The information of the second battery rack is 3. The energy storage system of claim 2, comprising one or more of the number of the second battery racks, a State of Health (SOH), a State of Charge (SOC), an output current, an output power, and a temperature.

4. The battery system control device The energy storage system of claim 2 , wherein information about the second battery racks is used to calculate a power weight value for each second battery rack.

5. The battery system control device 5. The energy storage system of claim 4, configured to calculate a total power command value for the second battery rack based on the output power values ​​of the first battery rack and the second battery rack, quantity information of the first battery rack, and quantity information of the second battery rack.

6. The battery system control device 6. The energy storage system of claim 5, configured to calculate an individual power command value for each second battery rack based on a power weighting value for each second battery rack and a total power command value for the second battery rack.

7. An energy storage system as described in claim 1, wherein the battery system control device interrupts the output of the DC / DC converter when the output of the PCS (Power Conversion System) indicates that charging / discharging operation has stopped.

8. The energy storage system according to claim 2 , wherein the charge or discharge command is transmitted to a PCS from an energy management system (EMS) of the energy storage system.

9. The second battery rack and the DC / DC converter are The energy storage system of claim 1 , wherein after the first battery rack is installed and operated in the energy storage system, additional battery racks are placed and operated in the energy storage system.

10. A battery system control device interlocked with one or more first battery racks and one or more second battery racks, at least one processor, A memory for storing at least one instruction to be executed by the at least one processor. Including, The at least one instruction: instructions to monitor the output of one or more DC / DC converters controlling the one or more first battery racks and the one or more second battery racks, respectively; and and an instruction to control an output of the one or more DC / DC converters in response to a result of the monitoring. Including, the first battery rack is not directly connected to the DC / DC converter, and output control according to the state of the first battery rack is not possible; A battery system control device in which the second battery rack reinforces the performance of the first battery rack through output control of the second battery rack using the DC / DC converter.

11. The instructions for monitoring the output of the one or more first battery racks and the one or more DC / DC converters include: The battery system control device according to claim 10 , further comprising an instruction to detect an output power value of the first battery rack that operates in accordance with a charge or discharge command of an energy storage system.

12. The command to control the output of the DC / DC converter in accordance with the monitoring result comprises: The battery system control device according to claim 10, further comprising an instruction to calculate an output power value output by each of the one or more second battery racks using the output power value of the first battery rack, information about the first battery rack, and information about the second battery rack.

13. The command to control the output of the DC / DC converter in accordance with the monitoring result comprises: instructions to calculate a total power command value for one or more second battery racks based on the output power values ​​of the first battery rack and the second battery rack, quantity information of the first battery racks, and quantity information of the second battery racks; and instructions to calculate an individual power command value for each of the second battery racks based on a power weight value for each second battery rack and a total power command value for the one or more second battery racks. The battery system control device according to claim 10 , comprising:

14. The battery system control device according to claim 11 , wherein the charge or discharge command is transmitted from an EMS (Energy Management System) to a PCS (Power Conversion System).

15. The second battery rack and the DC / DC converter are The battery system control device according to claim 11 , wherein after the first battery rack is installed and operated in the energy storage system, additional battery racks are placed and operated in the energy storage system.

16. A control method for an energy storage system including one or more first battery racks, one or more second battery racks, and one or more DC / DC converters that respectively manage the one or more second battery racks, comprising: monitoring the output of the one or more first battery racks and the one or more DC / DC converters; Detecting an output power value of the one or more first battery racks operated according to a charge or discharge command of the energy storage system; Calculating an output power value output by the one or more second battery racks using the output power value of the one or more first battery racks, information about the one or more first battery racks, and information about the one or more second battery racks; and controlling the output of the one or more DC / DC converters in accordance with the calculated output power value. Including, the first battery rack is not directly connected to the DC / DC converter, and output control according to the state of the first battery rack is not possible; A control method for an energy storage system, wherein the second battery rack reinforces the performance of the first battery rack through output control of the second battery rack using the DC / DC converter.

17. The step of calculating an output power value output by the one or more second battery racks includes: Calculating a total power command value for one or more second battery racks based on the output power values ​​of the first battery rack and the second battery rack, quantity information of the first battery racks, and quantity information of the second battery racks; and calculating an individual power command value for each of the second battery racks based on the output weight value for each second battery rack and the total power command value for the one or more second battery racks; 17. The method of claim 16, comprising:

18. The information of the one or more second battery racks includes:

17. The method for controlling an energy storage system according to claim 16, comprising one or more of the number, SOH, SOC, output current, output power, and temperature of the one or more second battery racks.

19. 17. The method of claim 16, further comprising the step of interrupting the output of the one or more DC / DC converters when an output of a power conversion system (PCS) indicates a stop of charging / discharging operations.

20. The method for controlling an energy storage system according to claim 16, wherein the charge or discharge command is transmitted from an EMS (Energy Management System) to a PCS.

21. The second battery rack and the DC / DC converter are The method for controlling an energy storage system according to claim 16 , wherein after the first battery rack is installed and operated in the energy storage system, additional battery racks are placed and operated in the energy storage system.

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