Energy storage system comprising new installation battery rack, and method for controlling the 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 new renewable energy, batteries that store power, and an existing power grid. In recent years, smart grids and new renewable energy have become more widespread, and as the efficiency and stability of the power grid are emphasized, 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 the energy storage system vary, and multiple battery systems can be connected to each other to form a large-capacity energy storage system.

[0004] In an energy storage system, the performance of some battery racks may deteriorate over time, and new battery racks may be added to existing battery racks to compensate for the performance. In this case, there may be a difference in performance between the newly added rack and the existing racks, and unnecessary rack balancing may be repeated due to the difference in performance between the racks. This causes a problem that even though a new battery rack is added to compensate for the performance, the new battery rack ends up following the performance of the existing rack. In other words, even though a new battery rack is added, the maximum performance (e.g., rated capacity, period of use, etc.) of the new battery rack cannot be fully utilized. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE PRESENT EMBODIMENT 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.

[0006] Another object of the present invention to solve the above problems is to provide an apparatus for controlling a battery 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 method for controlling an energy storage system including an existing battery rack and a new battery rack. [Means for solving the problem]

[0008] To achieve the above-mentioned object, an energy storage system according to one embodiment of the present invention may include a plurality of first battery racks; a plurality of battery protection units each managing the plurality of first battery racks; a plurality of second battery racks; a plurality of DC / DC converters each managing the plurality of second battery racks; 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 output of the plurality of battery protection units and the plurality of DC / DC converters and to control the output of the plurality of DC / DC converters.

[0009] The battery section control device detects output power values ​​of the multiple first battery racks, which operate in response to charging or discharging commands from the energy storage system, and can calculate 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.

[0010] The information of 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.

[0011] The battery section controller can calculate a power weighting value for each second battery rack using information about the plurality of second battery racks.

[0012] The battery section control device can also calculate a power command value for each of the second battery racks 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.

[0013] The battery section control device can interrupt the output of the plurality of DC / DC converters when an output of a power conversion system (PCS) indicates the stop of charging / discharging operations.

[0014] The charge or discharge command can be transmitted from an Energy Management System (EMS) to a PCS.

[0015] In order to achieve the above-mentioned another object, a battery system control device according to one embodiment of the present invention can be coupled to a plurality of battery protection units each managing a plurality of first battery racks and a plurality of DC / DC converters each managing a plurality of second battery racks, and can include at least one processor; and a memory for storing at least one instruction executed through the at least one processor.

[0016] 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 results of the monitoring.

[0017] 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.

[0018] The instruction to control the output of the multiple DC / DC converters according to the results of the monitoring may include an instruction to calculate output power values ​​output by the multiple second battery racks using output power values ​​of the multiple first battery racks, information about the multiple first battery racks, and information about the multiple second battery racks.

[0019] The instructions for controlling the output of the multiple 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 multiple 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.

[0020] The charge or discharge command can be transmitted from an Energy Management System (EMS) to a PCS.

[0021] In order to achieve the above-mentioned 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 each managing the plurality of first battery racks, a plurality of second battery racks, and a plurality of DC / DC converters each managing 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 output power values ​​of the plurality of first battery racks which operate in response to a charge or discharge command of the energy storage system; calculating output power values ​​output by the plurality of second battery racks using the output power values ​​of the plurality of first battery racks, information on the plurality of first battery racks, and information on the plurality of second battery racks; and controlling the output of the plurality of DC / DC converters in accordance with the calculated output power values.

[0022] The step of calculating output power values ​​output by the plurality of second battery racks may include the steps of: calculating an output weighted value of each second battery rack using information about the plurality of second battery racks; and calculating a power command value for each of the second battery racks 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.

[0023] The information of 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.

[0024] The method for controlling the energy storage system may include interrupting outputs of the plurality of DC / DC converters when an output of a power conversion system (PCS) indicates a stop of a charging / discharging operation.

[0025] The charge or discharge command can be transmitted from an Energy Management System (EMS) to a PCS. Effect of the Invention

[0026] 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.

[0027] This allows the performance of the new battery rack to be utilized to the maximum extent (e.g., 100%).

[0028] In addition, the present invention allows the system to operate in the same manner as the existing method by only modifying the firmware of the BSC without modifying the firmware of the PCS and PMS. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a block diagram of an existing energy storage system. [Diagram 2] FIG. 1 is a block diagram of an energy storage system according to an embodiment of the present invention. [Diagram 3] 4 shows the relationship between the output command value and the output value in each battery region when the energy storage system is started and stopped according to an embodiment of the present invention. [Figure 4]1 illustrates a concept of calculating the output control weights of each DC / DC converter in an augmentation domain according to an embodiment of the present invention. [Diagram 5] FIG. 4 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 PREFERRED EMBODIMENTS

[0030] Since the present invention can be modified in various ways and has 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 embodiment, but includes all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention. Similar reference numerals are used for similar components while describing each drawing.

[0031] Terms such as first, second, A, B, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only to distinguish one component from another. For example, a first component may be named a second component, and similarly, a second component may be named 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.

[0032] When a component is referred to as being "coupled" or "connected" to another component, it should be 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 referred to as being "directly coupled" or "directly connected" to another component, it should be understood that there are no other components in between.

[0033] The terms used in this application are merely used to describe certain embodiments and are not intended to limit the present invention. A singular expression includes a plural expression unless the context clearly indicates otherwise. In this application, the terms "include" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and are not intended to preclude the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0034] 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 the present invention belongs. 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.

[0035] Some terms used in this specification are defined as follows:

[0036] 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 [%].

[0037] A battery rack refers to a system with the smallest single structure that can be monitored and controlled through a BMS by connecting module units set by a battery manufacturer in series / parallel, and can be composed of multiple battery modules and one BPU or protection device.

[0038] 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.

[0039] A BSC (Battery System Controller) is a device that performs the highest level control of 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 multiple bank level structure.

[0040] Nominal capacity (Nominal Capa.) can refer to the set capacity [Ah] of a battery set by the battery manufacturer at the time of development.

[0041] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0042] FIG. 1 is a block diagram of an existing energy storage system.

[0043] The smallest unit of a battery that serves to store power in an energy storage system (ESS) is usually 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.

[0044] Referring to FIG 1, one battery rack may include a plurality of battery modules and one BPU 10 or protection device. The battery rack can be monitored and controlled through a Rack BMS (RBMS). The RBMS can monitor the current, voltage, and temperature of each battery rack under its management, calculate the SOC (Status Of Charge) of the battery based on the monitoring results, and control charging and discharging.

[0045] Meanwhile, the BPU (Battery Protection Unit) 10 is a device for protecting batteries from abnormal current and fault current in battery rack units. The BPU 10 may include a main contactor (MC), a fuse, a circuit breaker (CB) or a disconnect switch (DS), etc. The BPU can control the battery system in rack units by controlling the main contactor to turn on / off under the control of the RBMS. The BPU can also protect the battery from short circuit current using a fuse when a short circuit occurs. In this way, the existing battery system can be controlled through protection devices such as the BPU and switch gear.

[0046] Meanwhile, a battery section controller (BSC) 20 is provided in each battery section including a number of batteries and peripheral circuits and devices, and can monitor and control objects to be controlled 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 multiple bank-level structure.

[0047] In addition, a power conversion system (PCS) 40 provided for each battery section is a device that performs substantial charging and discharging based on a charge / discharge command from the EMS, and may include a power conversion unit (DC / AC inverter) and a controller. Meanwhile, the output of each BPU may be connected to the PCS 40 via a DC bus, and the PCS 40 may be connected to a grid. In addition, the EMS (Energy Management System) / PMS (Power Management System) 30 manages the entire ESS system.

[0048] In the conventional battery system as shown in FIG. 1, the battery system is controlled only through protective elements such as BPU and switch gear, and individual control taking into account individual characteristics of the battery system such as battery capacity, SOH, and SOC is not possible.

[0049] In this type of energy storage system, 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 appears 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.

[0050] At this time, there may be a performance difference between the newly added rack (which may be referred to as a second battery rack) and the previously installed rack (which may be referred to as a first battery rack), and according to the existing control method, unnecessary or excessive rack balancing is repeated, causing a problem that the newly added rack follows the deteriorated performance of the previously installed rack. That is, even though a new rack is added, the maximum performance (e.g., rated capacity, usage period, etc.) of the new battery rack cannot be fully utilized. In the embodiment 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 the existing battery rack at a later point in time, which includes a DC / DC converter for DC / DC conversion, and may be a battery rack that has already been used or has been refurbished.

[0051] FIG. 2 is a block diagram of an energy storage system according to an embodiment of the present invention.

[0052] 2 illustrates a system in which a number of 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 characteristics 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 in FIG. 1. The EMS (Energy Management System), also called PMS (Power Management System), manages the ESS system as a whole.

[0053] The BSC (Battery Section Controller) 200 can manage the status of each rack and notify the upper system (EMS) of the limit value of the battery that can be output. The BSC 200 can be implemented in a form mounted or installed in a desktop computer or the like. The BSC 200 can also be implemented as a separate device or controller. The PCS 400 is a device that actually performs charging and discharging based on a charging and discharging command received from the EMS 300, and can include a DC / AC power conversion unit and a controller.

[0054] On the other hand, when 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 being operated, i.e., when 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 balancing imbalance between the racks may occur if existing control methods are used.

[0055] Therefore, an energy storage system according to one embodiment of the present invention uses a DC / DC converter (within the augmentation area) instead of a BPU for multiple newly added battery racks, reducing or preventing problems such as a sudden degradation in performance of the newly added battery racks and balancing imbalance between the racks.

[0056] 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).

[0057] The DC / DC converter placed in the augmentation area allows the existing rack and the new battery rack to be electrically separated and operated. The output of the DC / DC converter can be actively controlled by the user, so even if there are differences in SOC, SOH, and capacity between each battery rack, it is possible to control the battery output taking into account the characteristics of each individual battery rack.

[0058] Each DC / DC converter is connected to the BSC 200 and the PCS 400. The BSC 200 can monitor and manage the states of not only the battery racks arranged in the existing area but also the battery racks arranged in the augmentation area.

[0059] On the other hand, from the perspective of end users who use the services provided by energy storage systems, an important issue is whether they can operate the batteries without changing the PCS and EMS they are currently using.

[0060] 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.

[0061] 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 rather than a BPU 100. Therefore, by using a DC / DC converter 150 dedicated to the battery rack (New Rack) newly added to the augmentation area instead of a battery protection unit (BPU), it is possible to provide an advantage of avoiding or reducing rapid deterioration of the newly added battery rack or balancing. In addition, it is possible to provide an advantage of only modifying the firmware of the BSC in the battery area without modifying the firmware of the PCS or EMS.

[0062] First, the start-up sequence of the energy storage system according to the present invention will be described.

[0063] Referring to FIG. 2, the EMS300 issues a charge / discharge command (P bat * ) The PCS300 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 output the power corresponding to the command. bat * The power output is:

[0064] 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 keeps track of the total output value (P bat * ) is monitored. Therefore, P bat * means the total output power required for the BPU racks in the existing area and the DC / DC racks in the augmentation area.

[0065] 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.

[0066] 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 *By multiplying the power output of each DC / DC rack by the power output of the BPU rack in the existing area, the BSC 200 calculates the charge / discharge command for the DC / DC converter by considering 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 is connected to the P aug * Outputs the power of the value.

[0067] In the embodiment of the present invention, the output power (P bat * The charge / discharge command for the output power (P bat * In this regard, the charge / discharge command for the output power can be expressed as 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 the output power depending on the situation. Similarly, the output value P aug * The charge / discharge command for the output value P aug * In this regard, the charge / discharge command for the output value P aug * The output value P required or demanded 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.

[0068] The series of steps in the startup sequence described above is completed within a very short time after the output of the PCS is started.

[0069] Next, the shutdown sequence of the energy storage system will be described.

[0070] When the system is stopped, the output of the PCS400 becomes 0. In this case, since the existing BPU area is a passive element area, 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 and DC / DC domains becomes 0, causing the system to stop operating.

[0071] FIG. 3 shows the relationship between the output command value and the output value in each battery region when the energy storage system is started and stopped according to an embodiment of the present invention.

[0072] During 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 * The battery rack in the augmentation area recognizes the value P aug * is calculated and transmitted to the augmentation region.

[0073] The augmentation region is P aug * At the time of outputting the value of (P bat * - P aug *At this time, the PCS command value is P bat * However, regardless of whether the EMS is augmented or not, the command value P bat * to the PCS. Thus, according to the present invention, the PCS and EMS can operate in the same manner as existing systems, regardless of whether augmentation is performed or not.

[0074] On the other hand, to explain the shutdown sequence, the PCS command value becomes 0 when the system is shut down. In this case, since the existing BPU domain is a passive element domain, the output of the battery rack changes depending on the output of the PCS. The DC / DC domain, which is the augmentation domain, has an output P aug * The output is controlled to 0 when the stop command is received from the BSC. aug * During the short time that the output is output, the BPU area temporarily accepts the output (-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.

[0075] FIG. 4 illustrates a concept of calculating the output control weighting value of each DC / DC converter in the augmentation domain according to an embodiment of the present invention.

[0076] 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 racks arranged in the augmentation area, and calculate the output weighting value of each DC / DC rack based on this value.

[0077] 4, the BSC 200 receives data such as SOC, SOH, current, voltage, and temperature of each battery rack from each DC / DC rack. The BSC uses this information to calculate the output weight value α 2 ,...α n can be calculated.

[0078] The following formula 1 is the total output command value P for the augmentation region. aug * The formula for calculating P is shown below. bat * , P aug * The unit of may be watts (W).

[0079]

number

[0080] 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.

[0081] 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 as follows:

[0082]

number

[0083] 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 the output power is calculated by multiplying the output power by the weighting value for each rack. Also, the sum of the output weighting values ​​for each DC / DC rack is 1.

[0084] In one embodiment, the battery racks within the augmentation area are assumed to be homogenous battery racks.

[0085] If the batteries in the augmentation region are of the same type and have similar SOH, the output weight value αj can be expressed as the following Equation 3.

[0086]

number

[0087] In addition, when the batteries in the augmentation area are of the same type and have similar SOH, the output weighting value for each rack during discharge can be determined as a ratio of the SOC of the rack to the SOC of all battery racks in the augmentation area, which can be defined as Equation 4 below.

[0088]

number

[0089] On the other hand, when the battery models are the same but the battery racks have different SOHs, the output weighting value for each battery rack can be determined taking into account not only the SOC of each rack but also the SOH.

[0090] For example, the output weight value for each battery rack during charging can be defined as Equation 5 below.

[0091]

number

[0092] In addition, the output weight value for each battery rack during discharge can be defined as Equation 6 below.

[0093]

number

[0094] In the above formulas 3 to 6, n, i, and j are integers. Therefore, the output weight value of the new battery rack #j can provide an amount of augmented power that the individual new battery rack #j must supply, and the output weight value can be included in a charge / discharge command.

[0095] FIG. 5 is a flow diagram of a control method for an energy storage system according to an embodiment of the present invention.

[0096] 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 each managing the plurality of first battery racks, a plurality of second battery racks, and a plurality of DC / DC converters each managing the plurality of second battery racks.

[0097] The battery section control device monitors the outputs of the plurality of battery protection units and the plurality of DC / DC converters (S510).

[0098] The battery section control device detects the output power values ​​of the plurality of first battery racks that operate according to a charge or discharge command of the energy storage system (S520).

[0099] Thereafter, the battery section control device calculates the output power value output by the second battery rack (S530). At this time, the output power value output by the second battery rack may be calculated using the output power value of the first battery rack, information on the first battery rack, and information on the second battery rack. More specifically, the step of calculating the output power value output by the second battery rack may calculate an output weight value of each second battery rack using information on the second battery rack, and calculate 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. At this time, the information on the second battery racks may include one or more of the number of the second battery racks, SOH, SOC, output current, output power, and temperature.

[0100] Thereafter, the outputs of the multiple DC / DC converters may be controlled according to the calculated output power value (S540).

[0101] FIG. 6 is a schematic block diagram of a battery system control device according to an embodiment of the present invention.

[0102] 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.

[0103] 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 results of the monitoring.

[0104] The processor may execute program commands stored in at least one of the memories. 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 comprised of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory may be comprised of at least one of a read only memory (ROM) and a random access memory (RAM).

[0105] The operation of the method according to the embodiment of the present invention can be embodied as a computer readable program or code in a computer readable recording medium. The computer readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. In addition, the computer readable recording medium can be distributed to computer systems connected through a network, and the computer readable program or code can be stored and executed in a distributed manner. In addition, the computer readable recording medium can include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. The program instructions can include not only machine language codes such as those created by a compiler, but also high-level language codes that can be executed by a computer using an interpreter, etc.

[0106] Some aspects of the invention have been described in the context of an apparatus, but it may also be presented in terms of a corresponding method, where a block or apparatus corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method may be presented 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, for example, 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.

[0107] Although the present invention has been described with reference to preferred embodiments thereof, those skilled in the art will understand that various modifications and variations of the present invention can be made without departing from the spirit and scope of the present invention as set forth in the following claims.

Claims

1. a plurality of first battery racks; a plurality of battery protection units each managing the plurality of first battery racks; a plurality of second battery racks; a plurality of DC / DC converters that respectively manage the plurality of second battery racks; and a battery section control device that monitors outputs of the plurality of battery protection units and the plurality of DC / DC converters in cooperation with the plurality of battery protection units and the plurality of DC / DC converters and controls outputs of the plurality of DC / DC converters.

23. An energy storage system comprising:

2. The battery section control device includes: Detecting output power values ​​of the plurality of first battery racks that operate according to a charge or discharge command of the energy storage system; The energy storage system of claim 1, wherein an output power value output by the plurality of second battery racks is calculated using the output power values ​​of the plurality of first battery racks, information of the plurality of first battery racks, and information of the plurality of second battery racks.

3. The information of the plurality of second battery racks includes:

3. The energy storage system of claim 2, comprising one or more of a number of the plurality of 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 section control device includes: The energy storage system of claim 2 or 3, further comprising: calculating a power output weight value of each second battery rack using information about the plurality of second battery racks.

5. The battery section control device includes:

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

6. The battery section control device includes:

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

7. The energy storage system of claim 1 , wherein the battery section control device interrupts the output of the plurality of DC / DC converters when an output of a power conversion system (PCS) indicates a stop of a charging / discharging operation.

8. The energy storage system of 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 energy storage system of claim 1 , wherein the second battery racks are managed only by the DC / DC converters among the battery protection units and the DC / DC converters.

10. A battery system control device that is linked to 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, at least one processor, A memory for storing at least one instruction executed by said at least one processor. Including, The at least one instruction: instructions to monitor outputs of the plurality of battery protection units and the plurality of DC / DC converters; and and a command to control outputs of the plurality of DC / DC converters in response to a result of the monitoring. A battery system control device comprising:

11. The command to monitor the outputs of the plurality of battery protection units and the plurality of DC / DC converters comprises: The battery system control device according to claim 10 , further comprising an instruction to detect output power values ​​of the first plurality of battery racks operated by a charge or discharge command of an energy storage system.

12. The command to control outputs of the plurality of DC / DC converters in response to the monitoring result includes: The battery system control device of claim 10, further comprising an instruction to calculate an output power value output by each of the plurality of second battery racks using output power values ​​of the plurality of first battery racks, information of the plurality of first battery racks, and information of the plurality of second battery racks.

13. The command to control outputs of the plurality of DC / DC converters in response to the monitoring result includes: an instruction to calculate a total power command value for the plurality of second battery racks based on output power values ​​of the plurality of first battery racks and the plurality of second battery racks, quantity information of the plurality of first battery racks, and quantity information of the plurality of second battery racks; and instructions to calculate an individual power command value for each of the plurality of second battery racks based on a power weighting value for each second battery rack and a total power command value for the plurality of second battery racks. The battery system control device according to claim 10 .

14. The battery system control device according to claim 11 , wherein the charge or discharge command is transmitted from an energy management system (EMS) to a power conversion system (PCS).

15. 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, monitoring outputs of the plurality of battery protection units and the plurality of DC / DC converters; Detecting output power values ​​of the plurality of first battery racks operated according to a charge or discharge command of the energy storage system; Calculating output power values ​​output by the plurality of second battery racks using output power values ​​of the plurality of first battery racks, information of the plurality of first battery racks, and information of the plurality of second battery racks; and controlling outputs of the plurality of DC / DC converters in accordance with the calculated output power value; A method for controlling an energy storage system, comprising:

16. The step of calculating output power values ​​output by the plurality of second battery racks includes: Calculating a total power command value for the plurality of second battery racks based on output power values ​​of the plurality of first battery racks and the plurality of second battery racks, quantity information of the plurality of first battery racks, and quantity information of the plurality of second battery racks; and calculating an individual power command value for each of the plurality of second battery racks based on a power weighting value for each second battery rack and a total power command value for the plurality of second battery racks. The method of claim 15, comprising:

17. The information of the plurality of second battery racks includes: The method of claim 15 , comprising one or more of a number of the plurality of second battery racks, a SOH, a SOC, an output current, an output power, and a temperature.

18. The method for controlling an energy storage system according to claim 15, further comprising the step of interrupting outputs of the plurality of DC / DC converters when an output of a power conversion system (PCS) indicates a stop of charging / discharging operations.

19. The method for controlling an energy storage system according to claim 15, wherein the charge or discharge command is transmitted from an EMS (Energy Management System) to a PCS.

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