Patent Publication Number: US-2022216716-A1

Title: Plug-in type energy storage system

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Korean Patent Application No. 10-2021-0000936, filed Jan. 5, 2021, the entire contents of which is incorporated herein for all purposes by this reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present disclosure relates to a plug-in type energy storage system. 
     Description of the Related Art 
     A power network that supplies electricity produced by power plants does not perform a function of storing electric power. Recently, as the amount of generation of renewable energy increases, the development of an energy storage system configured to store the electricity is required. The energy storage system may store electrical energy produced from renewable energy sources and provide the electrical energy to the power network when needed. The energy storage system may operate in a method of charging and discharging the electricity to and from batteries. Each batteiy composed of rechargeable secondary cells deteriorates while repeatedly charging and discharging, so performance thereof deteriorates, and a power converter for controlling the power of each batteiy is also exposed to failure due to the charging and discharging. Therefore, it is necessary to exchange the batteries and the power converter that are included in the energy storage system. 
     DOCUMENTS OF RELATED ART 
     (Patent Document 1) KR 10-1634012 B1 
     SUMMARY OF THE INVENTION 
     An objective according to an exemplary embodiment of the present disclosure is to provide a plug-in type energy storage system that includes a plurality of battery racks and is provided with a battery power control unit for each battery rack so that each of the battery racks may be charged or discharged independently. 
     In addition, another objective according to the exemplary embodiment of the present disclosure is to provide a plug-in type energy storage system in which a plurality of battery modules constituting each battery rack and a battery power control unit for controlling each battery module are integrally formed to allow the same to be easily exchanged in a plug-in method. 
     A plug-in type energy storage system according to the exemplary embodiment of the present disclosure includes: one or a plurality of battery racks configured to store power; and a panel configured to control charging or discharging of each battery rack, wherein each battery rack may include: one or a plurality of battery modules configured to store the power; a control module connected to each battery module and the panel to control the charging or discharging of each battery module according to a control signal received from the panel; and a conversion module connected to the control module to convert waveforms of the power into direct current or alternating current according to a control signal received from the control module. 
     In addition, the plug-in type energy storage system according to the exemplary embodiment of the present disclosure may further include a casing configured to accommodate each battery module, the conversion module, and the control module. 
     In addition, in the battery racks, each battery module, the conversion module, and the control module may be accommodated in the casing to become one package, thereby allowing module exchange in units of battery racks. 
     In addition, the control module may include one or more of the following: an AC connector configured to transmit and receive the power to and from the panel; a DC connector configured to transmit and receive the power to and from each battery module; a communication connector configured to transmit and receive data to and from the panel or each battery module; an AC protection part connected to the conversion module and the AC connector to prevent propagation of an accident; a DC protection part connected to the conversion module and each batteiy module to prevent the propagation of the accident; and a rack control unit connected to the communication connector to collect a state of each batteiy module and control the conversion module on the basis of the control signal received from the panel. 
     In addition, the conversion module may include one or more of the following: a low-pass filter connected to the AC protection part to remove harmonics of AC power; a DC link capacitor connected to the DC protection part to equalize a voltage of DC power; and a power converter connected to the low-pass filter and the DC link capacitor, and configured to change the waveforms of the power into the alternating current or the direct current according to a control signal received from the rack control unit. 
     In addition, the rack control unit may include: a batteiy management system configured to monitor the state of each battery module and control the charging or discharging; and a power controller configured to control the power converter as the battery management system controls the charging or discharging. 
     In addition, the plurality of batteiy modules may be arranged to be spaced apart from each other in a vertical direction or a left and right direction inside the casing, the control module and the conversion module may be arranged to be spaced apart from each other in the vertical direction or the left and right direction of each battery module inside the casing, and the casing may discharge air introduced from a gap spaced apart between each batteiy module, the control module, and the conversion module to outside of the casing, and further include a fan formed on one side of the casing. 
     In addition, the control module may have one surface thereof on which the AC connector, the DC connector, and the communication connector are arranged, and each battery module may have one surface thereof to which the DC connector of the control module or the DC line connected to other battery modules are connected. 
     In addition, the control module and the conversion module each may have air holes formed therein so that the air introduced from a front surface of the control module passes through the control module and the conversion module, thereby being discharged to an upper surface of the conversion module, and each air hole formed on the upper surface of the conversion module may be formed at a position corresponding to the fan of the casing. 
     In addition, the panel may include: an energy management system configured to generate a control signal for controlling the charging or discharging of the plurality of battery racks and provide the control signal to each of the plurality of battery racks; and an AC bus connected to the plurality of battery racks to share the power of the plurality of battery racks. 
     In addition, in the plurality of battery racks, at least one battery rack may include battery cells of a type different from that of another battery rack, or at least one battery rack comprises reusable battery cells, and according to the type or a charge state of each of the plurality of battery racks, the energy storage system may be configured to simultaneously control at least one battery rack to be charged and at least another battery rack to be discharged, or control an amount of power to be charged to or discharged from the at least one battery rack and the at least another battery rack to be different from each other. 
     In addition, when any one of the plurality of battery racks is exchanged or a new battery rack is additionally connected, the energy management system may receive information about a state of each battery rack from the rack control unit and automatically perform control according to a type or a charge state of each battery cell of each battery rack. 
     In addition, in order to exchange each battery module, the control module, or the conversion module, the casing may be configured such that each battery module, the control module, or the conversion module are attachable and detachable, respectively. 
     In addition, the plurality of battery racks may be connected to the panel by a predetermined number to form one cluster, and the energy storage system may be controlled in units of cluster. 
     The features and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. 
     Prior to this, the terms or words used in the present specification and claims should not be construed as conventional and dictionary meanings, but it should be interpreted as meaning and concept consistent with the technical spirit of the present disclosure on the basis of the principle that the inventor can adequately define the concept of each term to best describe his or her invention. 
     According to the exemplary embodiment of the present disclosure, the plurality of batteiy modules and the batteiy power management unit integrally constitute each battery rack, so when exchanging batteries, the batteries may be integrally exchanged in units of batteiy racks. 
     In addition, according to the exemplary embodiment of the present disclosure, since the battery power control unit is provided for each of the plurality of batteiy racks to perform charging or discharging in units of battery racks, the batteiy racks constituting one energy storage system may be composed of heterogeneous batteries or reusable batteries. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view illustrating a plug-in type energy storage system according to an exemplary embodiment of the present disclosure. 
         FIG. 2  is a view illustrating a battery rack and a panel of the plug-in type energy storage system according to the exemplary embodiment of the present disclosure. 
         FIG. 3  is a view illustrating a structure of the batteiy rack of the plug-in type energy storage system according to the exemplary embodiment of the present disclosure. 
         FIG. 4  is a side view taken along line A-A′ of  FIG. 3 . 
         FIG. 5  is a view illustrating a combination of a control module and a conversion module of the plug-in type energy storage system according to the exemplary embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Objectives, advantages, and features of exemplary embodiments of the present disclosure will become more apparent from the following description of the exemplary embodiments taken in conjunction with the accompanying drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used to refer to the same components as much as possible even if displayed on different drawings. In addition, terms such as “one surface”, “the other surface”, “first”, “second”, etc. are used to distinguish one component from another component, and the components are not limited by the terms. In addition, it should be understood that even when a component is expressed in a singular number, a plurality of corresponding components may exist. Hereinafter, in describing the exemplary embodiments of the present disclosure, detailed descriptions of related known technologies that may unnecessarily obscure the gist of the exemplary embodiments of the present disclosure will be omitted. 
     Hereinafter, an exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a view illustrating a plug-in type energy storage system  10  according to the exemplary embodiment of the present disclosure.  FIG. 2  is a view illustrating a battery rack  100  and a panel  200  of the plug-in type energy storage system  10  according to the exemplary embodiment of the present disclosure. In the present specification, the “plug-in type energy storage system  10 ” may be briefly described as a “plug-in ESS  10 ”. 
     As shown in  FIGS. 1 and 2 , the plug-in type energy storage system  10  according to the exemplary embodiment of the present disclosure may include: one or a plurality of battery racks  100  configured to store electric power; and the panel  200  configured to control charging or discharging of each battery rack  100 . In addition, each battery rack  100  may include: one or a plurality of battery modules  110  configured to store electric power; a control module  120  connected to each battery module  110  and the panel  200  to control charging or discharging of each battery module  110  according to a control signal received from the panel  200 ; and a conversion module  130  connected to the control module  120  to convert waveforms of power into direct current or alternating current according to a control signal received from the control module  120 . In addition, the plug-in ESS  10  may further include a casing  140  configured to accommodate each battery module  110 , the conversion module  130 , and the control module  120 . 
     The plug-in ESS  10  may be connected to a grid G. The Grid G is a commercial power network. Power plants, various load devices, different energy storage systems, renewable energy production devices, and the like may be connected to the grid G. The renewable energy production devices may include various power generation methods used by wind power generators, solar cells, tidal power generators, etc. The plug-in ESS  10  may be connected to the grid G to charge power from the grid G or discharge the power to the grid G. The grid G may be connected to the plug-in ESS  10  through a circuit breaker CB and a transformer TR. The circuit breaker CB may prevent fault current generated in the grid G from being transmitted to the plug-in ESS  10 , and may prevent the fault current generated in the plug-in ESS  10  from being transmitted to the grid G. The transformer TR may mutually convert voltage of the grid G and voltage of the plug-in ESS  10  to each other. 
     In the plug-in ESS  10 , the plurality of battery racks  100  is connected to the panel  200  by a predetermined number to form one cluster  300 , and the energy storage system may be controlled in units of cluster  300 . The cluster  300  is a unit in which the plurality of battery racks  100  is connected to one panel  200 . The plug-in ESS  10  may be composed of a plurality of clusters  300 . The plurality of battery racks  100  included in one cluster  300  may be charged or discharged by one panel  200 . As an example,  FIGS. 1 and 2  illustrate one cluster  300  including six battery racks  100 . 
     The plug-in ESS  10  may include the panel  200  and the batteiy racks  100 . The panel  200  may include: an energy management system  220  configured to generate control signals for controlling charging or discharging of the plurality of battery racks  100  and respectively provide the control signals to the plurality of battery racks  100 ; and an AC bus  210  connected to the plurality of batteiy racks  100  and configured to share power of the plurality of battery racks  100 . 
     The energy management system  220  may control charging or discharging of the batteiy racks  100  connected to the panel  200 . From the battery racks  100 , the energy management system  220  may obtain information about the battery racks  100 , the information including a current state of charge (SOC), a deterioration state of health (SOH), voltage, current, types of battery cells included in each battery rack  100 , whether a corresponding batteiy is a reusable battery, and the like. The energy management system  220  may control discharge of the batteiy racks  100  according to the power required by the grid (G) or the load. 
     The AC bus  210  may be connected to the plurality of battery racks  100 . A circuit breaker CB may be connected between the AC bus  210  and each batteiy rack  100 . The AC bus  210  transmits power that the plurality of battery racks  100  is charging or discharging. The power in alternating current waveforms flows in the AC bus  210 . 
     Each battery rack  100  may include each battery module  110 , a control module  120 , and a conversion module  130 . 
     Each batteiy module  110  may include a plurality of batteiy cells. The batteiy cells may be connected to each other in series or in parallel. Each battery cell is a secondary cell capable of charging or discharging power. Each battery cell may be the secondary cell of various types, made of lithium-ion, lithium-polymer, iron phosphate, etc. 
     The control module  120  may control charging or discharging of each battery rack  100 . The control module  120  may include one or more of the following: an AC connector  123 AC configured to transmit and receive power to and from the panel  200 , a DC connector  123 DC configured to transmit and receive the power to and from each battery module  110 , a communication connector  124  configured to transmit and receive data to and from the panel  200  or each battery module  110 , an AC protection part  122 AC connected to the conversion module  130  and the AC connector  123 AC so as to prevent propagation of an accident, a DC protection part  122 DC connected to the conversion module  130  and each battery module  110  so as to prevent the propagation of the accident, and a rack control unit  121  connected to the communication connector  124  to collect a state of each battery module  110  and control the conversion module  130  on the basis of a control signal received from the panel  200 . 
     The AC connector  123 AC is connected to an AC line  230  and the AC line  230  is connected to the AC bus  210  of the panel  200  to transmit and receive power in alternating current waveforms. The DC connector  123 DC is connected to a DC line  150 , and the DC line  150  is connected to each battery module  110  to transmit and receive power in direct current waveforms. The communication connector  124  is connected to a communication line  240 , and the communication line  240  is connected to the energy management system  220  of the panel  200  to transmit and receive control signals or data. An AC protection part  122 AC may be connected between the AC connector  123 AC and a low-pass filter  132  of the conversion module  130 . The AC protection part  122 AC may block fault current transmitted from the conversion module  130  or the AC connector  123 AC, so as to prevent propagation of an accident. The AC protection part  122 AC may include an AC relay for performing a switching function to connect or disconnect power. The AC protection part  122 AC may include an AC fuse for blocking an overcurrent. The DC protection part  122 DC may be connected between the DC connector  123 DC and a DC link capacitor  133  of the conversion module  130 . The DC protection part  122 DC may block the fault current transmitted from the conversion module  130  or the DC connector  123 DC to prevent the propagation of the accident. The DC protection part  122 DC may include a DC relay for performing the switching function to connect or disconnect the power. The DC protection part  122 DC may include a DC fuse for blocking the overcurrent. Fault current includes overcurrent generated due to short circuit, damage, or the like. 
     The rack control unit  121  may be connected to the communication connector  124  to receive the state of each battery module  110 , and may receive a control signal from the energy management system  220 . The rack control unit  121  may control the conversion module  130  on the basis of a control signal received from the energy management system  220 . The rack control unit  121  may include: a battery management system  121   a  configured to monitor a state of each battery module  110  and controlling charging or discharging thereof; and a power controller  121   b  configured to controlling a power converter  131  as the battery management system  121   a  controls the charging or discharging. 
     The battery management system (BMS)  121   a  may recognize the state of each battery module  110 . The battery management system  121   a  may calculate a charge state, a deterioration state, internal resistance, and the like of each battery module  110  on the basis of data such as voltage, current, temperature, and the like of each battery module  110 , the data being received from the communication connector  124 . The battery module  110  may further include a module BMS, and the module BMS may provide information about the state of each battery rack  100  to the battery management system  121   a  of the control module  120 . The battery management system  121   a  may control charging or discharging of each battery module  110  through the power controller  12  l b.  The power controller  121   b  may control the power converter  131  of the conversion module  130  to charge or discharge each battery module  110  on the basis of the control signal generated by the battery management system  121   a.    
     The conversion module  130  may convert waveforms of power into alternating current and direct current. The conversion module  130  may include one or more of the following: the low-pass filter  132  connected to the AC protection part  122 AC to remove harmonics of AC power, the DC link capacitor  133  connected to the DC protection part  122 DC to equalize the voltage of DC power, and the power converter  131  connected to the low-pass filter  132  and the DC link capacitor  133  and configured to change the waveforms of power into alternating current or direct current according to the control signal received from the rack control unit  121 . 
     The low-pass filter  132  may be connected between the power converter  131  and the AC protection part  122 AC so as to remove harmonics from the AC waveforms output from the power converter  131 . The DC link capacitor  133  may be connected between the power converter  131  and the DC protection part  122 DC so as to equalize the voltage of the DC power output from the power converter  131 . The power converter  131  may convert the waveforms of power from alternating current to direct current or from direct current to alternating current according to a control signal received from the power controller  121   b  of the rack control unit  121 . The power converter  131  converts alternating current into direct current during charging, and converts direct current into alternating current during discharging. 
     A conventional energy storage system has a six-layer structure proceeding in order from a grid G, to a transformer IR, to a panel, to a power conversion system (PCS), to a battery control panel (BCP), and to battery racks. Such a structure has many layers constituting one energy storage system, so the structure is disadvantageous in price and space optimization. In addition, alternating current and direct current are converted in one PCS, and the plurality of battery racks is connected in parallel to the DC bus of the battery control panel, so as to simultaneously charge and discharge the plurality of battery racks. In this structure, each battery rack shares the DC bus. In such a structure, the plurality of battery racks connected to the same DC bus should be operated under the same voltage and SOC states. Due to the difference in contact resistance of the battery racks or the difference in the resistance of the battery cells, such a structure is highly likely to cause impedance imbalance, and may cause unbalanced charge and discharge between the battery racks. Such a structure may not solve the imbalance of the battery racks, so system maintenance is difficult and the reliability is low. In such a structure, since different types of battery racks or reusable battery racks are unable to be mixed, and states of the battery racks in use and a state of new battery rack are different, it is difficult to connect to the same DC bus, and thus it is difficult to expand the batteiy racks. 
     In contrast, the plug-in ESS  10  according to the exemplary embodiment of the present disclosure may independently perform charging and discharging for each battery rack  100 . The plug-in ESS  10  is provided with the conversion module  130  that converts direct current and alternating current for each batteiy rack  100 . The plurality of battery racks  100  is connected in parallel to the AC bus  210  of the panel  200  to transmit AC power. Each of the plurality of battery racks  100  connected in parallel to the AC bus  210  may perform charging or discharging, individually. Therefore, among the plurality of batteiy racks  100 , the energy management system  220  may control any one of the batteiy racks  100  to charge while discharging other batteiy racks  100 . That is, each batteiy rack  100  may be individually controlled. In addition, the plug-in ESS  10  has a four-layer structure proceeding in order from the grid G, to the transformer IR, to the panel  200 , and to the batteiy racks  100 , so the structure is advantageous in optimizing the price and space of the system. In addition, since a part through which DC power flows in the plug-in ESS  10  exists only inside each batteiy rack  100 , and in the plug-in ESS  10 , since wires for connecting the panel  200  and the battery racks  100  to each other and a wire connecting the panel  200  and the transformer TR to each other exist only where AC power flows, wiring may be simplified. 
     In addition, in the plurality of batteiy racks  100 , at least one battery rack  100  may include batteiy cells of a type different from that of other battery racks  100 , or at least one batteiy rack  100  may include reusable battery cells. In this case, according to the type or charge state of each of the plurality of batteiy racks  100 , the energy management system  220  may control to charge at least one batteiy rack  100  while simultaneously discharging other at least one batteiy rack  100 , or may control the amount of power charged to or discharged from the at least one battery rack and the other at least one batteiy rack to be different from each other. 
     When the types of batteiy racks  100  are different, the capacity, rated voltage, rated current, charge states, deterioration states, internal resistance, and the like of battery racks  100  may be different. Even with the same type of battery racks  100 , reusable battery racks  100  may have different capacity, rated voltage, rated current, charge states, deterioration states, internal resistance, and the like. 
     In the conventional energy storage system, when different types of battery racks are connected in parallel to one DC bus, there is a problem that an imbalance occurs in charging and discharging, so other types of battery racks may not be used. 
     In contrast, since the plug-in ESS  10  according to the exemplary embodiment of the present disclosure is provided with the conversion module  130  in each battery rack  100 , and the battery racks are connected in parallel to one AC bus  210  so that each battery rack  100  may be individually controlled, different types of battery racks  100  or reusable battery racks  100  may be used. 
     For example, at least some of the plurality of battery racks  100  are battery racks  100  including battery cells of a first type, some others thereof may be battery racks  100  including battery cells of a second type, yet some others thereof may be battery racks  100  including reusable battery cells of the first type. Since the battery racks  100  of the first type, the battery racks  100  of the second type, and the reusable battery racks  100  of the first type have different characteristics of battery cells, the amount of charge and the amount of discharge may be different. Therefore, according to the characteristics and state of each battery, the plug-in ESS  10  may control at least one or more battery racks  100  of the plurality of battery racks  100  to perform charging, and may simultaneously control the rest of the battery racks  100  to perform discharging. 
     The energy management system  220  individually controls charging or discharging for each battery rack  100  in the plurality of battery racks  100  on the basis of the states of the battery racks  100 , and may control the amount of power to be charged or discharged to be different for each battery rack  100 . For example, the energy management system  220  may control any one of the battery racks  100  to perform charging by a first amount of power, may control another battery rack  100  to perform discharging by a second amount of power, and yet another battery rack  100  to perform charging by a third amount of power. 
     The energy management system  220  determines the states of the battery racks  100 , and generates a control signal to be transmitted to each battery rack  100  in accordance with a power demand instruction received from the outside. The energy management system  220  calculates, in units of battery racks, the amount of power that may be charged or discharged on the basis of a charge state, a deterioration state, and the number of charge/discharge cycles, and may transmit, to each battery rack  100 , a control signal for obtaining power by which the power converter  131  of each batteiy rack  100  may operate at maximum efficiency. In this process, which battery racks  100  will be operated is determined, or how many battery racks  100  will be operate is also determined by using the amount of power required from the outside, the batteiy state of each battery rack  100 , and the maximum power efficiency point of the power converter  131 . 
       FIG. 3  is a view illustrating a structure of a battery rack  100  of the plug-in type energy storage system  10  according to the exemplary embodiment of the present disclosure.  FIG. 4  is a side view taken along line A-A′ of  FIG. 3 .  FIG. 5  is a view illustrating a combination of a control module  120  and a conversion module  130  of the plug-in type energy storage system  10  according to the exemplary embodiment of the present disclosure. 
     As shown in  FIGS. 3 and 4 , in each batteiy rack  100  of the plug-in ESS  10 , each battery module  110 , the conversion module  130 , and the control module  120  are accommodated in the casing  140  to become one package, thereby allowing module exchange in units of batteiy racks. 
     One battery rack  100  may include the plurality of batteiy modules  110 , the control module  120 , and the conversion module  130 . Each of the plurality of battery modules  110  may be individually packaged and accommodated in the casing  140 . Each batteiy module  110 , the control module  120 , and the conversion module  130  may be individually packaged and accommodated in the casing  140 . The control module  120  and the conversion module  130  may be configured in an integral form or in a form in which the same are individually manufactured and then combined to each other. 
     Conventionally, in the energy storage system, since the battery racks  100  are connected in parallel to the DC bus, when exchanging some of the battery racks  100 , a difference occurs in the characteristics of the battery racks  100 , and thus it is difficult to exchange the battery racks  100 . In addition, the conventional energy storage system has a structure in which it is difficult to exchange only the battery racks  100  because the battery racks  100 , the DC bus, and other components are integrally configured. In addition, initial installation of the conventional energy storage system is cumbersome because each component should be individually transported and assembled in a local site. 
     In contrast, the plug-in ESS  10  according to the exemplary embodiment of the present disclosure has a convenient structure for exchanging the battery racks  100  in units of battery racks  100  because each of the battery racks  100  is independently packaged. In addition, since the battery racks  100  are connected to the AC bus  210  and each battery rack  100  includes the conversion module  130 , the battery racks  100  may be exchanged without stopping the entire plug-in ESS  10 . In addition, since each battery rack  100  is independently packaged, it is convenient to transport the same, and it is also convenient because the operation may be performed in units of battery racks  100  even at the time of initial installation or exchange of the batteries. 
     The plug-in ESS  10  may arrange the battery racks  100  by distribution. Since it is not necessary to densely arrange the battery racks  100  in one space, the plug-in ESS  10  may be installed in a space-efficient manner. Since the battery racks  100  connected to one panel  200  are controlled by the energy management system  220  of the panel  200 , an installation position of the battery racks  100  is sufficient as long as the position may secure the connections with the panel  200 . 
     As shown in  FIGS. 3 to 5 , the plurality of battery modules  110  is arranged inside the casing  140  so as to be spaced apart from each other in the vertical direction or the left and right direction, the control module  120  and the conversion module  130  are arranged inside the casing  140  so as to be spaced apart from each other in the vertical direction or the left and right direction of the batteiy module  110 , and the casing  140  may further include a fan  141  formed on one side of the casing  140  and configured to discharge, to the outside of the casing  140 , air introduced from a gap spaced apart between the battery modules  110 , the control module  120 , and the conversion module  130 . 
     The casing  140  accommodates the battery modules  110 , the control module  120 , and the conversion module  130  so as to package the same in units of batteiy racks  100 . The control module  120  and the conversion module  130  are arranged on an upper part of the casing  140 , and the plurality of batteiy modules  110  may be arranged on the remaining part of the casing  140 . The casing  140  may be formed as a box in which a front surface  140   a  thereof is open, and opposite side surfaces  140   c,  a rear surface  140   d,  an upper surface  140   b,  and a lower surface  140   e  thereof are closed. In order to exchange the battery modules  110 , the control module  120 , or the conversion module  130 , the casing  140  may be configured such that the battery modules  110 , the control module  120 , or the conversion module  130  are respectively attachable and detachable. When the battery modules  110 , the control module  120 , and the conversion module  130  are configured to be attachable to and detachable from the front surface  140   a  of the casing  140  in a sliding manner, it is easy to exchange each component. As shown in  FIGS. 3 and 4 , the casing  140  may arrange the battery modules  110 , the control module  120 , and the conversion module  130  in the vertical direction, or although not shown, may arrange the battery modules  110 , the control module  120 , and the conversion module  130  in the left and right direction. The shape of the casing  140  and the arrangement positions of the batteiy modules  110 , the control module  120 , and the conversion module  130  may be changed in various ways, and various methods may be used for the attachment and detachment method. 
     The casing  140  may accommodate the plurality of battery modules  110  to be spaced apart from each other by a predetermined distance. Air may flow through a gap spaced apart between the plurality of batteiy modules  110 . The rear surface  140   d  of the casing  140  and each battery module  110  may be accommodated to be spaced apart from each other by a predetermined distance. The casing  140  may include a fan  141  on one side thereof. The fan  141  is positioned at the rear of the upper surface  140   b  of the casing  140  to operate so that air is discharged to the upper surface  140   b  of the casing  140 , the air moving in a direction from the front surface  140   a  to the rear surface  140   d  of the casing  140 . The flows of air is indicated by arrows in  FIGS. 3 and 4 . The control module  120  and the conversion module  130  are accommodated in an upper part of the casing  140  and may be arranged to be spaced apart from the battery module  110  by a predetermined distance. 
     The control module  120  and the conversion module  130  may be respectively provided with air holes AH formed thereon so that the air introduced from the front surface  120   a  of the control module  120  passes through the control module  120  and the conversion module  130 , thereby being discharged to the upper surface  130   b  of the conversion module  13 . The air hole AH formed in the upper surface  130   b  of the conversion module  130  may be formed at a position corresponding to the fan  141  of the casing  140 . The air holes AH may be respectively formed in the front surface  120   a  and rear surface  120   b  of the control module  120 , the air hole AH of the front surface  130   a  of the conversion module  130  may be formed at a position corresponding to the air hole AH formed in the rear surface  120   b  of the control module  120 , and the air hole AH of the upper surface  130   b  of the conversion module  130  may be formed to correspond to the position of the fan  141  of the casing  140 . The air introduced into the air hole AH of the front surface  120   a  of the control module  120  may cool the inside of the control module  120 , move to the air hole AH of the front surface  130   a  of the conversion module  130 , cool the inside of the conversion module  130 , and then be discharged to the air hole AH of the upper surface  130   b  of the conversion module  130 . 
     A fan  137  may be arranged in the air hole AH formed in the front surface  130   a  of the conversion module  130 . The fan  137  arranged on the front surface  130   a  of the conversion module  130  suctions air from the air hole AH formed in the rear surface  120   b  of the control module  120  and discharges the air to the inside of the conversion module  130 . The fan  137  may be arranged in the air hole AH formed in the upper surface  130   b  of the conversion module  130 . The fan  137  arranged on the upper surface  130   b  of the conversion module  130  may suction air inside the conversion module  130  and discharge the air to the outside of the conversion module  130 . 
     Since the control module  120  includes the AC connector  123 AC, the DC connector  123 DC, the communication connector  124 , and the rack control unit  121 , heat is relatively low compared with the conversion module  130 . Since the conversion module  130  includes the power converter  131  that converts direct current and alternating current to and from each other, the heat is relatively high compared with the control module  120 . Since air is introduced into the conversion module  130  passing a path through the control module  120 , both the control module  120  and the conversion module  130  may be well cooled. Since there is provided a structure in which the air hole AH formed in the upper surface  130   b  of the conversion module  130  is positioned to correspond to the fan  141  of the casing  140 , and the fan  141  of the casing  140  suctions and discharges the air that is discharged from the conversion module  130 , it is easy to cool the conversion module  130 . 
     The control module  120  has one surface thereof on which the AC connector  123 AC, the DC connector  123 DC, and the communication connector  124  are arranged, and each battery module  110  has one surface thereof to which the DC connector  123 DC of the control module  120  or the DC line  150  connected to other battery modules  110  may be connected.  FIG. 3  exemplarily illustrates the structure in which the AC connector  123 AC, the DC connector  123 DC, and the communication connector  124  are arranged on the front surface  120   a  of the control module  120 , the front surface  120   a  of each battery module  110  is connected to the DC connector  123 DC of the control module  120  or the DC line  150  connected to other battery modules  110 , and the control module  120  and the battery modules  110  are arranged vertically. The control module  120  may include a first DC bus connector  126  and a first AC bus connector  127 , which are connected to the conversion module  130  and positioned on the surface (e.g., the rear surface  120   b ) facing the conversion module  130 . The conversion module  130  may include a second DC bus connector  134  and a second AC bus connector  135 , which are connected to the control module  120 , on the surface (e.g., the front surface  130   a ) facing the control module  120 . The first and second DC bus connectors  126  and  134  are connected to each other to transmit DC power, and the first and second AC bus connectors  127  and  135  are connected to each other (refer to dotted line in  FIG. 5 ) to transmit AC power. The control module  120  may include, on the rear surface  120   b  thereof, a first control signal connector  128  connected to the conversion module  130 , and the conversion module  130  includes, on the front surface  130   a  thereof, a second control signal connector  128  connected to the control module  120 . The first and second control signal connectors  128  and  136  are connected to each other (refer to the dotted line in  FIG. 5 ) and transmits a control signal that allows the power controller  121   b  to control the power converter  131 . By independently configuring the control module  120  and the conversion module  130  and forming the same to be connected to each other, when a problem occurs in any one of the control module  120  and the conversion module  130 , only a corresponding module may be exchanged. 
     The DC line  150  is connected to the front surface  110   a  of each battery module  110 . The DC line  150  connected to a front surface of each battery module  110  is connected to the front surface  110   a  of each ad j acent battery module  110  or the DC connector  123 DC of the control module  120 . The battery modules  110  may be connected in series with each other. Since each battery module  110  is individually packaged, the battery modules  110  may be exchanged in units of battery module  110 . Since the plurality of battery modules  110  is connected to each other in series, charging and discharging may be performed simultaneously even though there is a difference in characteristics between the battery modules  110  by exchanging any one battery module  110 . 
     Depending on the arrangement relationship of the battery modules  110 , the control module  120 , and the conversion module  130 , components such as various connectors, fans, and holes, which are formed on one surface of the battery modules  110 , the control module  120 , and conversion module  130  may be arranged on the front surface, side surfaces, rear surface, upper and lower surfaces, etc. 
     When any one of the plurality of battery racks  100  is exchanged or anew battery rack  100  is additionally connected, the energy management system  220  may receive information about the state of each battery rack  100  from the rack control unit  121  and automatically perform control according to the type or the charge state of each battery cell of each battery rack  100 . When the batteiy racks  100  and the panel  200  are connected to each other through the AC line  230  and the communication line  240 , the energy management system  220  automatically transmits and receives data to and from the rack control unit  121  of each batteiy rack  100 . According to an algorithm for operating other battery racks  100  in the past, the energy management system  220  may operate the new battery rack  100  in conjunction with a conventional batteiy rack  100 . 
     As described above, the present disclosure has been described in detail through specific exemplary embodiments, the exemplary embodiments are for describing the present disclosure in detail, and the present disclosure is not limited thereto. In addition, it is clear that the present disclosure may be modified or improved by those skilled in the art within the technical spirit of the present disclosure. 
     All simple modifications to changes of the present disclosure belong to the scope of the present disclosure, and the specific protection scope of the present disclosure will be made clear by the appended claims.