JP7602045B2 - Energy storage system including newly installed battery rack and method for controlling same - Google Patents

Description

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.

The present invention relates to an energy storage system and a method for controlling an energy storage system, and more specifically to an energy storage system including a new or later-installed battery rack and a method for controlling an energy storage system.

An energy storage system (ESS) is a system that connects new renewable energy sources, batteries that store electricity, and the existing power grid. In recent years, smart grids and new renewable energy sources 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 together to form a large-capacity energy storage system.

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 such a difference in performance between the racks may cause unnecessary rack balancing to be repeated. This causes a problem in 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.

US Patent Application Publication No. 2016/0226268

The objective of the present invention to solve the above problems is to provide an energy storage system that includes an existing battery rack and a new battery rack.

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.

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.

To achieve the above 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 monitors the output of the plurality of battery protection units and the plurality of DC/DC converters in conjunction with the plurality of battery protection units and the plurality of DC/DC converters and controls the output of the plurality of DC/DC converters.

The battery section control device detects the output power values of the multiple first battery racks that operate in response to a charge or discharge command from the energy storage system, and can 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.

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.

The battery section control device can calculate an output weight value for each second battery rack using information about the plurality of second battery racks.

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.

The battery section control device can interrupt the output of the multiple DC/DC converters when the output of the PCS (Power Conversion System) indicates the stop of charging/discharging operations.

The above charging or discharging command can be transmitted from the EMS (Energy Management System) to the PCS.

In order 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 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.

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

The instructions to monitor the outputs of the plurality of battery protection units and the plurality of DC/DC converters may include instructions to detect the output power values of the plurality of first battery racks that operate in response to a charge or discharge command of the energy storage system.

The command to control the output of the plurality of DC/DC converters according to the results of the monitoring may include a command 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 on the plurality of first battery racks, and information on the plurality of second battery racks.

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 weighting value for each of the second battery racks using information about the plurality of second battery racks; and instructions for calculating a power command value for each of the second battery racks based on the output weighting 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.

The above charging or discharging command can be transmitted from the EMS (Energy Management System) to the PCS.

To achieve the above-mentioned further 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 can include a step of monitoring the outputs of the plurality of battery protection units and the plurality of DC/DC converters; a step of detecting the output power values of the plurality of first battery racks that operate in response to a charge or discharge command of the energy storage system; a step of 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 on the plurality of first battery racks, and information on the plurality of second battery racks; and a step of controlling the outputs of the plurality of DC/DC converters according to the calculated output power values.

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 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.

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.

The control method for the energy storage system may include a step of interrupting the output of the plurality of DC/DC converters when the output of the PCS (Power Conversion System) indicates the stop of charging/discharging operations.

The above charging or discharging command can be transmitted from the EMS (Energy Management System) to the PCS.

According to the above-described embodiment of the present invention, when adding a new battery rack to an energy storage system, unnecessary or excessive rack balancing can be prevented or reduced.

This allows the new battery rack to utilize its full potential (e.g., 100%).

In addition, the present invention allows the system to be operated in the same way as the existing method, by only modifying the BSC firmware, without modifying the PCS and PMS firmware.

FIG. 1 is a block diagram of an existing energy storage system. FIG. 1 is a block diagram of an energy storage system according to an embodiment of the present invention. 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. 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. FIG. 4 is a flow chart of a control method for an energy storage system according to an embodiment of the present invention. 1 is a schematic block diagram of a battery system control device according to an embodiment of the present invention.

The present invention can be modified in various ways and can have various embodiments, so a specific embodiment will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to a specific embodiment, but should be understood to include all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention. Similar reference numerals are used for similar components when describing each drawing.

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 invention. The term "and/or" includes a combination of multiple related listed items or any of multiple related listed items.

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

The terms used in this application are merely used to describe certain embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions 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.

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.

Some terms used in this specification are defined as follows:

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 [%].

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

A battery bank can refer to a large 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.

The BSC (Battery System Controller) is a device that performs the highest level of control for a battery system that includes 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.

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

The preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

Figure 1 is a block diagram of an existing energy storage system.

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, depending on the device or system in which the battery is used, the battery rack can also be called a battery pack.

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 an RBMS (Rack BMS). The RBMS can monitor the current, voltage, and temperature of each battery rack under its management, calculate the battery's SOC (Status Of Charge) based on the monitoring results, and control charging and discharging.

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 be 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.

Meanwhile, a Battery Section Controller (BSC) 20 is provided in each battery section, which is composed of 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 control device of a battery system including a bank-based battery system including multiple battery packs, and may also be used as a control device in a battery system with a multiple bank-level structure.

The power conversion system (PCS) 40 provided for each battery section is a device that performs actual charging and discharging based on charge/discharge commands 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. The EMS (Energy Management System)/PMS (Power Management System) 30 manages the ESS system as a whole.

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

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.

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 may be repeated, causing a problem that the newly added rack follows the degraded 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 and including a DC/DC converter for DC/DC conversion, and may be a battery rack that has already been used or has been refurbished.

Figure 2 is a block diagram of an energy storage system according to an embodiment of the present invention.

Figure 2 shows 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 characteristics to the energy storage system shown in Figure 1. The existing energy storage system may include the EMS 300, PCS 400, BPU 100, battery rack (old rack), and BSC 200 as described through Figure 1. The EMS (Energy Management System), also called the PMS (Power Management System), manages the ESS system as a whole.

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 on a desktop computer, etc. 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 the charging and discharging command received from the EMS 300, and can be configured to include a DC/AC power conversion unit and a controller.

On the other hand, when augmentation is performed to add new battery racks to reinforce the existing battery racks in addition to the multiple battery racks and BPUs that are currently being operated, i.e., when the existing battery racks and new battery racks coexist due to augmentation, the performance of the new battery racks may rapidly deteriorate or problems such as imbalances in balancing between the racks may occur if the existing control method is used.

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 imbalances between racks.

The DC/DC converter 150 may include a main body and a DC/DC controller. The DC/DC converter 150 performs DC/DC conversion between the battery and the power conversion system (PCS).

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, making it possible to control the battery output taking into account the characteristics of each individual battery rack, even if differences in SOC, SOH, and capacity occur between each battery rack.

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.

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

The present invention provides an augmentation method using a DC/DC converter that requires only modifying the BSC firmware in the battery area, without modifying the PCS and EMS firmware.

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 newly added battery rack (New Rack) in the augmentation area instead of a battery protection unit (BPU), it is possible to provide the advantage of avoiding or reducing rapid deterioration of the newly added battery rack or balancing. It is also possible to provide the advantage of only modifying the firmware of the BSC in the battery area without modifying the firmware of the PCS or EMS.

First, we will explain the startup sequence of the energy storage system according to the present invention.

2, the EMS 300 transmits a charge/discharge command (P _bat ^* ) to the PCS 300 in the same manner as in the existing method. The PCS 300 receives the charge/discharge command (P _bat ^* ) and outputs power corresponding to the command. At this time, the power of P _bat ^* is preferentially (temporarily) output from the BPU rack arranged in the existing area.

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 monitors the total output value (P _bat ^* ) from all battery racks linked to itself. 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.

On the other hand, the BSC 200 calculates the value P aug * output by the new battery rack in the augmentation area based on at _least the values output by the battery racks in the existing area, the quantity information of the battery racks in the existing area, ^and the quantity information of the battery racks in the augmentation area.

The BSC 200 also calculates an output weighting 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. The output weighting value for each battery rack is multiplied by P _aug ^* to calculate the output value of each DC/DC rack. That is, the BSC 200 calculates a charge/discharge command for the DC/DC converter in consideration of 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 outputs power of the P _aug ^* value.

In an embodiment of the present invention, a charge/discharge command for an output power (P _bat ^* ) can also be referred to as a directive for the output power (P _bat ^* ). In this regard, a charge/discharge command for an output power can be expressed or symbolized as a value of the output power (P _bat ^* ) that is required or requested by a charge/discharge command resulting in the output power (P _bat ^* ). Thus, P _bat ^* can be used to express a charge/discharge command and an output power depending on the context. Similarly, a charge/discharge command for an output value P _aug ^* can also be referred to as a directive for the output value P _aug ^* . In this regard, a charge/discharge command for an output value can be expressed or symbolized as a value of the output value P _aug ^* that is required or requested by a charge/discharge command resulting in the output value P _aug ^* . Thus, P _aug ^* can be used to specify a charge/discharge command and an output value depending on the context.

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

Next, we will explain the shutdown sequence of the energy storage system.

When the system is shut down, the output of the PCS 400 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 and therefore maintains the output P _aug ^* . That is, for a very short moment, the augmentation area outputs P _aug ^* and the BPU area temporarily receives this output. During that time, the BSC detects that the output to the PCS has become 0 and corrects the output command value P _aug ^* of the DC/DC area to 0. Through this process, the outputs of all racks in the BPU area and DC/DC area become 0 and the system operation is stopped.

Figure 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 an embodiment of the present invention.

During the startup sequence, when power P _bat ^* is output from a battery in the existing area through the PCS which has received a charge/discharge command (P _bat ^* ) from the EMS, the BSC recognizes the output value P _bat ^* , calculates the value P _aug ^* output by the battery rack in the augmentation area, and transmits it to the augmentation area.

At the time when the augmentation region outputs the value of P _aug ^* , the battery in the existing region outputs a power of (P _bat ^* - P _aug ^* ). At this time, the command value of the PCS is held at P _bat ^* , but the EMS transmits a constant command value P _bat ^* to the PCS regardless of whether augmentation is present. In this way, according to the present invention, the PCS and EMS can operate in the same way as existing systems, regardless of whether augmentation is present.

Meanwhile, 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, holds the output P _aug ^* until it receives a command from the BSC, and controls the output to 0 from the point of receiving a shutdown command from the BSC. During the short time that the augmentation domain outputs P _aug ^* , the BPU domain temporarily accepts the output (-P _aug ^* ). When the output of the DC/DC domain becomes 0 due to a shutdown command from the BSC, the output of the BPU domain also becomes 0.

Figure 4 shows the concept of calculating the output control weighting value for each DC/DC converter in the augmentation region according to an embodiment of the present invention.

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

4, the BSC 200 receives data such as the SOC, SOH, current, voltage, and temperature of each battery rack from each DC/DC rack, and the BSC can use this information to calculate the output weights _α2 , ... _αn of each DC/DC rack.

The following Equation 1 shows a formula for calculating the total power command value P _aug ^* for the augmentation region: In the embodiment of the present invention, the units of P _bat ^* and P _aug ^* may be Watts (W).

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

Equation 2 shows an equation for calculating the output command values P _DC/DC-1 ^* to P _DC/DC-n ^* of the DC/DC racks in the augmentation area.

In Equation 2, the output command value of the DC/DC rack is calculated by multiplying the total output command value P _aug ^* for the augmentation region by the weighting value for each rack. Also, the sum of the output weighting values of each DC/DC rack is 1.

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

When the batteries in the augmentation area are of the same type and have similar SOH, the output weight value α _j of the battery rack #j during charging can be expressed as Equation 3 below.

In addition, if 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. That is, it can be defined as shown in the following Equation 4.

On the other hand, if 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.

For example, the output weighting value for each battery rack during charging can be defined as follows:

In addition, the output weighting value for each battery rack during discharge can be defined as follows:

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 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.

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

The energy storage system control method according to 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.

The battery section control device monitors the outputs of the multiple battery protection units and the multiple DC/DC converters (S510).

The battery section control device detects the output power values of the first plurality of battery racks that operate in response to a charge or discharge command from the energy storage system (S520).

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

Then, the output of multiple DC/DC converters can be controlled according to the calculated output power value (S540).

Figure 6 is a schematic block diagram of a battery system control device according to an embodiment of the present invention.

The battery system controller (or battery section controller) 200 may include at least one processor; and a memory for storing at least one instruction executed through the at least one processor.

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

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 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).

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. The computer readable recording medium can also be distributed to 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 can also include hardware devices such as ROM, RAM, flash memory, etc. that are specially configured to store and execute program instructions. 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.

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.

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

Claims (16)

A plurality of second battery racks are added to 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, and a battery section control device,
a plurality of DC/DC converters each managing the plurality of second battery racks,
the battery section control device monitors outputs of the battery protection units and the DC/DC converters in cooperation with the battery protection units and the DC/DC converters, and controls outputs of the DC/DC converters ;
the plurality of second battery racks and the plurality of DC/DC converters are additionally installed in the energy storage system after the plurality of first battery racks are installed in the energy storage system to add the plurality of first battery racks;
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;
A plurality of second battery racks are added to the energy storage system, which calculates 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. The information of the plurality of second battery racks includes:
A plurality of second battery racks added to the energy storage system of claim 1 , including one or more of the 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. The battery section control device includes:
A plurality of second battery racks added to the energy storage system according to claim 1 or 2 , wherein information about the plurality of second battery racks is used to calculate an output weight value of each second battery rack. The battery section control device includes:
A plurality of second battery racks added to the energy storage system described in claim 3, 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 . The battery section control device includes:
5. The energy storage system of claim 4, further comprising: a plurality of second battery racks configured to calculate individual power command values 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 . 2. The plurality of second battery racks added to 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 PCS (Power Conversion System) indicates a stop of charging/discharging operations . The plurality of second battery racks added to the energy storage system according to claim 1 , wherein the charging or discharging command is transmitted from an EMS (Energy Management System) of the energy storage system to a PCS. A battery system control device that is linked to a plurality of DC/DC converters that respectively manage a plurality of second battery racks that are added to an energy storage system including a plurality of first battery racks and a plurality of battery protection units that respectively manage the plurality of first battery racks,
at least one processor;
a memory for storing at least one instruction to be executed by said at least one processor;
The at least one instruction:
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 a result of the monitoring ,
the plurality of second battery racks and the plurality of DC/DC converters are additionally installed in the energy storage system after the plurality of first battery racks are installed in the energy storage system to add the plurality of first battery racks;
The command to control outputs of the plurality of DC/DC converters in response to the monitoring result includes:
and a command 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.
Battery system control device. 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 8 , 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. The command to control outputs of the plurality of DC/DC converters in response to the monitoring result includes:
9. The battery system control device of claim 8, further comprising: 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 an instruction to calculate individual power command values for each of the plurality of second battery racks based on output weighted values for each second battery rack and the total power command value for the plurality of second battery racks. The battery system control device according to claim 9 , wherein the charge or discharge command is transmitted from an energy management system (EMS) to a power conversion system (PCS). A method for controlling a plurality of second battery racks added to an energy storage system including a plurality of first battery racks and a plurality of battery protection units that respectively manage the plurality of first battery racks , comprising:
each of the second battery racks is managed by a corresponding one of a plurality of DC/DC converters;
The control method includes:
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;
a step of calculating an output power value output by the second battery racks using output power values of the first battery racks, information on the first battery racks, and information on the second battery racks; and a step of controlling outputs of the DC/DC converters in accordance with the calculated output power values ,
A method for controlling a plurality of second battery racks added to an energy storage system, wherein the plurality of second battery racks and the plurality of DC/DC converters are additionally installed in the energy storage system after the plurality of first battery racks are installed in the energy storage system to add the plurality of first battery racks. The step of calculating output power values output by the plurality of second battery racks includes:
13. The method for controlling a plurality of second battery racks added to an energy storage system as described in claim 12, comprising: a step of 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 a step of calculating individual power command values for each of the plurality of second battery racks based on output weighted values for each second battery rack and the total power command value for the plurality of second battery racks . The information of the plurality of second battery racks includes:
The method for controlling a plurality of second battery racks added to an energy storage system as described in claim 12 , including one or more of the number, SOH, SOC, output current, output power, and temperature of the plurality of second battery racks. 13. The method for controlling a plurality of second battery racks added to an energy storage system as described in claim 12 , comprising a step of interrupting the output of the plurality of DC/DC converters when an output of a power conversion system (PCS) indicates a stop of charging/discharging operations. The method for controlling a plurality of second battery racks added to an energy storage system according to claim 12 , wherein the charge or discharge command is transmitted from an EMS (Energy Management System) to a PCS.