Patent Publication Number: US-11647596-B2

Title: Battery rack

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a Continuation of U.S. patent application Ser. No. 16/394,718 filed on Apr. 25, 2019, which claims priority to Korean Patent Applications No. 10-2018-0048503 filed on Apr. 26, 2018 in the Korean Intellectual Property Office (KIPO), the entire disclosure of which is incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Embodiments of the present invention relate to a battery rack. 
     2. Description of the Related Art 
     In general, it is necessary for an energy storage system (ESS) to have a long life in order to be used in a product for a long period time. However, when battery cells included in the battery rack are continuously exposed to a high temperature environment, the battery cells may be rapidly deteriorated, or safety problems such as ignition or explosion may occur. 
     In this regard, cooling fans are installed for each battery module provided in a conventional battery rack to cool the battery cells in the art. However, in this case, there are problems in that a large amount of energy is consumed and costs are increased, as well as, there is a limitation in cooling efficiency because it depends on simple air cooling by an outside air. 
     Meanwhile, in a case of the conventional battery rack, there is a limitation in the number of battery cells housed in each of a plurality of battery modules forming the battery rack, and there is also a limitation in improvements in an aspect of an energy density such as increasing the number of battery cells per unit volume. 
     As an example of the prior art, Korean Patent Registration No. 10-1278506, which is registered on Jun. 19, 2013, discloses a rack system of a battery module for energy storage, however, still has lack of improvement in the energy density and life-span properties. 
     SUMMARY OF THE INVENTION 
     It is an object of embodiments of the present invention to provide a battery rack capable of increasing cooling efficiency of a plurality of battery cells of each battery module housed in a housing. 
     In addition, another object of embodiments of the present invention is to provide a battery rack in which a cooling member in contact with a plurality of battery cells comes into direct contact with an external refrigerant (outside air), such that cooling efficiency may be improved. 
     Further, another object of embodiments of the present invention is to provide a battery rack in which one battery module may be provided with more than two times battery cells therein than the conventional battery rack. 
     Further, another object of embodiments of the present invention is to provide a battery rack in which the number of battery rack components such as module controllers installed for each battery module and module bus bars included in each battery module is decreased, such that costs and time during manufacturing may be reduced. 
     Further, another object of embodiments of the present invention is to provide a battery rack capable of minimizing a risk of safety accident during connecting a plurality of battery submodules in each battery module. 
     Further, another object of embodiments of the present invention is to provide a battery rack in which cooling fans may be provided on one side of an entire battery rack to effectively cool a plurality of battery modules. 
     Further, another object of embodiments of the present invention is to provide a battery rack capable of uniformly cooling a plurality of battery modules when the entire battery rack is provided with a cooling fan on one side thereof. 
     Further, another object of embodiments of the present invention is to provide a battery rack that may have sufficient structural durability without a separate module case for housing a plurality of battery cells. 
     Further, another object of embodiments of the present invention is to provide a battery rack capable of reducing the number of battery modules per battery rack from one-half to one-third of the conventional battery rack. 
     Furthermore, another object of embodiments of the present invention is to provide a battery rack capable of efficiently forming a high-voltage battery rack system for an energy storage system (ESS). 
     In order to achieve the above objects, according to one aspect of the present invention, there is provided a battery rack including: a housing; a plurality of battery modules stacked in the housing; and connection members configured to electrically connect the plurality of battery modules, wherein each of the plurality of battery modules includes a plurality of battery submodules stacked on each other, and each of the plurality of battery submodules includes: at least one cooling member; and a plurality of battery cells located on both sides with the at least one cooling member interposed therebetween, wherein at least two of the plurality of battery cells are located on each of both sides of the at least one cooling member. 
     The plurality of battery cells may be in surface contact with the at least one cooling member. 
     The cooling member may include: contact parts to which the plurality of battery cells are in contact; and exposed parts which extends from at least one end of the contact parts at a predetermined angle with respect to the contact parts. 
     The exposed part may be exposed to at least one surface of each of the plurality of battery modules. 
     The number of the one or more cooling members may correspond to the number of battery cells which are in contact with one side of the at least one cooling member of the plurality of battery cells. 
     Each of the plurality of battery submodules may further include a fixing frame configured to fix and support the cooling member and the plurality of battery cells. 
     Each of the plurality of battery submodules may include a first fixing frame configured to fix and support at least two of the cooling members. 
     Each of the plurality of battery submodules may include a second fixing frame configured to be coupled with the first fixing frame, so as to support the plurality of battery cells and fix positions thereof. 
     Each of the plurality of battery modules may include at least one fixed beam configured to fix and support the plurality of stacked battery submodules. 
     Each of the plurality of battery modules may further include a protective cover unit configured to protect the plurality of stacked battery submodules, and the protective cover unit may include a front cover unit and a rear cover unit, which are located on both sides among outer surfaces of the plurality of battery submodules in a direction in which the plurality of battery submodules are stacked, and side cover units located on sides from which electrode tabs of the battery submodules protrude. 
     Each of the plurality of battery modules may include at least one latch screw which is coupled to the front cover unit and includes a latch groove formed by cutting away at least a part of an outer peripheral surface thereof inward. 
     Each of the plurality of battery modules may include a grip groove formed by cutting away at least a part of the side cover unit toward the battery submodule. 
     Each of the plurality of battery modules may include elastic pads each of which is interposed between one or more battery submodules adjacent to each other in the plurality of battery submodules. 
     The battery rack may further include: a cooling fan located at an upper or a lower side of the plurality of stacked battery modules to dissipate heat generated from the plurality of battery modules. 
     The plurality of battery modules may be stacked at a predetermined distance, and the predetermined distance may be gradually increased from one side of the upper and lower sides, in which the cooling fan is located, toward the other side. 
     The cooling fan may be located at one side of the direction in which the battery submodules are stacked at the upper or lower side of the plurality of stacked battery modules, and a closed surface on a side, in which the cooling fan is located among peripheral surfaces perpendicular to the direction in which the plurality of battery modules are stacked, may be spaced apart from the plurality of battery modules at a predetermined distance. 
     Battery cells facing each other of the plurality of battery cells on both sides of the at least one cooling member in each of the battery submodules may be connected to each other in series or in parallel, and the plurality of battery submodules in each of the battery modules may be connected to each other in series or parallel to. 
     According to embodiments of the present invention, the cooling efficiency of a plurality of battery cells of each battery module provided in the housing may be increased. 
     In addition, according to the embodiments of the present invention, the cooling member in contact with the plurality of battery cells comes into direct contact with the external refrigerant (outside air), such that the cooling efficiency may be improved. 
     In addition, according to the embodiments of the present invention, one battery module may be provided with more than two times battery cells therein than the conventional battery rack. 
     In addition, according to the embodiments of the present invention, the number of battery rack components such as module controllers installed for each battery module and module bus bars included in each battery module is decreased, such that costs and time during manufacturing may be reduced. 
     Further, according to the embodiments of the present invention, it is possible to minimize the risk of safety accident during connecting the plurality of battery submodule in each battery module. 
     In addition, according to the embodiments of the present invention, the cooling fan may be provided on one side of an entire battery rack to effectively cool the plurality of battery modules. 
     In addition, according to the embodiments of the present invention, it is possible to uniformly cool the plurality of battery modules when the entire battery rack is provided with the cooling fan on one side thereof. 
     In addition, according to the embodiments of the present invention, the battery rack may have sufficient structural durability without a separate module case for housing a plurality of battery cells. 
     In addition, according to the embodiments of the present invention, it is possible to reduce the number of battery modules per battery rack from one-half to one-third of the conventional battery rack. 
     Further, according to the embodiments of the present invention, a high-voltage battery rack system for an energy storage system (ESS) may be efficiently formed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a perspective view illustrating a battery rack according to an embodiment of the present invention; 
         FIG.  2    is a perspective view illustrating a battery module of the battery rack according to the embodiment of the present invention; 
         FIG.  3    is an exploded perspective view of a battery submodule included in a battery module of the battery rack according to the embodiment of the present invention; 
         FIG.  4    is a perspective view illustrating the battery submodule included in the battery module of the battery rack according to the embodiment of the present invention; 
         FIG.  5    is a perspective view illustrating a state in which the battery submodule and a fixed beam are coupled in the battery module of the battery rack according to the embodiment of the present invention; 
         FIG.  6    is a plan view illustrating an electrical connection structure between a plurality of battery submodules in the battery module of the battery rack according to the embodiment of the present invention. 
         FIG.  7    is a perspective view illustrating a bus bar assembly included in the battery module of the battery rack according to the embodiment of the present invention; 
         FIG.  8    is a perspective view illustrating a state in which a front cover unit is disassembled from the battery module of the battery rack according to the embodiment of the present invention; 
         FIG.  9    is a perspective view illustrating a state in which a rear cover unit is disassembled from the battery module of the battery rack according to the embodiment of the present invention; 
         FIG.  10    is a side view schematically illustrating a state of dissipating heat in a plurality of battery modules disposed in the battery rack according to the embodiment of the present invention are dissipated; 
         FIG.  11    is a front view illustrating the battery rack according to the embodiment of the present invention; 
         FIG.  12    is an exploded perspective view of a battery submodule included in a battery module of a battery rack according to another embodiment of the present invention; 
         FIG.  13    is a perspective view illustrating the battery submodule included in the battery module of the battery rack according to another embodiment of the present invention; 
         FIG.  14    is a perspective view illustrating a state in which the battery submodule and a fixed beam are coupled in the battery module of the battery rack according to another embodiment of the present invention; and 
         FIG.  15    is a perspective view illustrating the battery module of the battery rack according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. However, these are merely illustrative examples and the present invention is not limited thereto. 
     In descriptions of the embodiments of the present invention, publicly known techniques that are judged to be able to make the purport of the present invention unnecessarily obscure will not be described in detail. Referring to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views. In addition, the terms as used herein are defined by taking functions of the present disclosure into account and can be changed according to the custom or intention of users or operators. Therefore, definition of the terms should be made according to the overall disclosure set forth herein. 
     It should be understood that the technical spirit and scope of the present invention are defined by the appended claims, and the following embodiments are only made to efficiently describe the present invention to persons having common knowledge in the technical field to which the present invention pertains. 
       FIG.  1    is a perspective view illustrating a battery rack  1  according to an embodiment of the present invention. 
     Referring to  FIG.  1   , the battery rack  1  according to the embodiment of the present invention may include a housing  20 , a plurality of battery modules  10  stacked in the housing  20 , and connection members  30  configured to electrically connect the plurality of battery modules  10 . 
     At this time, at least a part among peripheral surfaces of the housing  20  perpendicular to a direction in which the plurality of battery modules  10  are stacked may be sealed, and the remaining parts of the peripheral surfaces may be opened. In particular, a side face on which a front surface of the battery module  10  is located may be opened, such that an operator may easily install the plurality of battery modules  10  in the housing  20  during installing the battery rack  1 . 
     Meanwhile, a closed surface  21 , which is sealed among the peripheral surfaces of the housing  20 , will be described in detail below. 
     Further, the plurality of battery modules  10  may be electrically connected to each other by the connection member  30 , and preferably, forms the battery rack  1  according to the embodiment of the present invention with being connected in series to each other. 
     Meanwhile, the battery rack  1  according to the embodiment of the present invention may further include a battery rack controller  50  configured to control the plurality of battery modules  10 . 
     At this time, the plurality of battery modules  10  may be connected to the battery rack controller  50  through the connection members  30 . When short-circuit occurs in any one of the plurality of battery modules  10 , the battery rack controller  50  may prevent a safety accident such as a fire or an explosion by disconnecting the electrical connection of a high voltage. 
       FIG.  2    is a perspective view illustrating the battery module  10  of the battery rack  1  according to the embodiment of the present invention. 
     Referring to  FIG.  2   , each of the plurality of battery modules  10  included in the battery rack  1  according to the embodiment of the present invention may include a plurality of battery submodules  100  stacked on each other. 
     Specifically, the battery module  10  may include a plurality of battery submodules  100  stacked to face each other, and a protective cover unit  200  for protecting the plurality of stacked battery submodules  100 . 
     Meanwhile, the protective cover unit  200  may include a front cover unit  210  and a rear cover unit  220 , which are located on both sides among outer surfaces of the plurality of battery submodules  100  in a direction in which the plurality of battery submodules  100  are stacked. At this time, the plurality of battery submodules  100 , the front cover unit  210  and the rear cover unit  220  may be located parallel to each other. 
     In addition, among the outer surfaces of the plurality of battery submodules  100  stacked in the battery module  10 , other side faces except for the front cover unit  210  and the rear cover unit  220  sides may be opened to be exposed to an outside. However, it is not limited thereto, and a side face of the battery module  10 , from which electrode tabs  112  of the battery cell  110  protrude, may be protected from external foreign matters by side cover units  230 . 
     In this regard, upper and lower surfaces of the battery module  10  except for the front surface, rear surface and side faces thereof may be exposed to the outside, and at least a part of a cooling member  120  (illustrated in  FIG.  3   ) to be described below may be exposed to the outside of the battery module  10 , thus to effectively dissipate heat generated from the plurality of battery cells. 
     In addition, the battery module  10  may include a first terminal  11  and a second terminal  12  formed on the front surface thereof, which are connected to the connection members so as to electrically connect the plurality of battery modules  10 . At this time, the first terminal  11  and the second terminal  12  are formed together on one edge portion of the front surface of the battery module  10 , such that the operator may easily install and manage the battery rack  1  according to the embodiment of the present invention. 
     Meanwhile, each of the battery modules  10  may include a grip groove  231  formed by cutting away at least a part of the side cover unit  230  toward the plurality of battery submodules  100  in the direction in which the plurality of battery submodules  100  are stacked. 
     Specifically, the battery module  10  of the battery rack  1  according to the embodiment of the present invention may be formed by stacking the plurality of battery submodules  100 . At this time, a predetermined space may be formed by cutting away a part of the side cover unit  230  inward the battery module  10  between an upper edge portion of a fixing frame  130  of the plurality of stacked battery submodules  100  and the side cover unit  230 . That is, the grip groove  231  may be formed at an upper end of the side cover unit  230  in the direction in which the battery submodule  100  is stacked. 
     Thereby, a user or the operator may easily lift the battery module  10  by gripping the grip grooves  231 , and therefore operation efficiency during transporting and installing the battery module  10  may be improved. 
     In addition, the battery module  10  of the battery rack  1  according to the embodiment of the present invention may further include at least one latch screw  600  which may be screwed to the front cover unit  210 . At this time, the latch screw  600  may include a latch groove  610  formed by cutting away at least a part of an outer peripheral surface thereof inward. Thereby, the user or operator may move the battery module  10  by hooking a latch member (not illustrated) such as a handle formed in a hook shape to the latch groove  610 . 
     That is, the user or operator may easily move the battery module  10  in a horizontal direction by hooking the latch member such as a handle to the latch groove  610  of the latch screw  600  coupled to the front surface of the battery module  10 , and then pushing or pulling the battery module  10 . Thereby, the battery module  10  may be easily installed and moved during installing it in the battery rack  1  according to the embodiment of the present invention. 
       FIG.  3    is an exploded perspective view of the battery submodule  100  included in the battery module  10  of the battery rack  1  according to the embodiment of the present invention, and  FIG.  4    is a perspective view illustrating the battery submodule  100  included in the battery module  10  of the battery rack  1  according to the embodiment of the present invention. 
     Referring to  FIGS.  3  and  4   , each of the plurality of battery submodules  100  may include at least one cooling member  120 , and the plurality of battery cells  110  located on both sides with at least one cooling member  120  interposed therebetween. 
     In this case, each of the plurality of battery cells  110  included in the battery rack  1  according to the embodiment of the present invention may include a cell body  111 , and electrode tabs  112  protruding from one side of the cell body  111 . Meanwhile, in the battery submodule  100  of the battery rack  1  according to the embodiment of the present invention, two electrode tabs  112  will be described based on an unidirectional polarity battery cell  110  protruding from one side of the cell body  111 , while a battery rack according to another embodiment of the present invention, which includes bidirectional polarity battery cell  110 ′, will be described below. 
     In addition, at least two of the plurality of battery cells  110  may be located on each of both sides of at least one cooling member  120  arranged side by side. That is, each of the plurality of battery submodules  100  may include at least four battery cells  110 . 
     At this time, each of the plurality of battery submodules  100  may include at least two cooling members  120 , and each of two or more battery cells  110  on one of both sides of the battery submodule  100  may be located corresponding to each of two or more cooling members  120 . 
     Further, the plurality of battery cells  110  may come into surface contact with at least one cooling member  120 . Specifically, each of the one or more cooling members  120  may include contact parts  121  which are formed in a plate shape to come into surface contact with at least one battery cell  110 , and exposed parts  122  which extend from at least one end of the contact parts  121  at a predetermined angle with respect to the contact parts  121 . More specifically, the exposed parts  122  may extend from at least one end of the contact parts  121  perpendicularly to the contact part  121 . Thereby, the exposed parts  122  of the cooling member  120  form upper and lower surfaces of the battery submodule  100  to be exposed to the outside, and the exposed parts  122  exposed to the outside may come into contact with an outside air to be subject to convective heat transfer. Referring to  FIG.  2   , it can be confirmed a configuration in which the exposed parts  122  of the cooling members  120  in the battery module  10  are exposed to the outside. 
     Further, the cooling member  120  may be made of a material having a high thermal conductivity such as aluminum Al to cool the plurality of battery cells  110  in contact with the cooling member  120 . The plurality of battery cells  110  may be effectively cooled through the exposed parts  122  which are exposed to the outside by coming into direct surface contact with the contact parts  121  of the highly thermal-conductive cooling member  120  in a large area. A cooling method of the battery cell  110  will be described in detail below. 
     Meanwhile, the number of the one or more cooling members  120  may be determined corresponding to the number of battery cells  110  which are in contact with one side of at least one cooling member  120  of the plurality of battery cells  110 . 
     That is, when two battery cells  110  are located at one side of one battery submodule  100  to come into contact with at least one cooling member  120 , each of the plurality of battery submodules  100  may include two cooling members  120 , and each of the two battery cells  110  may come into surface contact with the contact parts  121  of each of the two cooling members  120 . 
     In addition, the two cooling members  120  in one battery submodule  100  may be arranged side by side on the same plane. Specifically, the two cooling members  120  may be arranged side by side so that the contact parts  121  thereof are located on the same plane, thereby two battery cells  110  on one side of the two cooling members  120  may also be located side by side. Referring to  FIG.  2   , the cooling members  120  are arranged side by side on both sides in the direction in which the plurality of battery submodules  100  are stacked. 
     Thereby, each one battery cell  110  comes into contact with both sides of one cooling member  120 , such that the possibility of electrical communication between at least two battery cells  110  through the cooling member  120  on one side of one battery submodule  100  may be blocked. 
     However, the number of the battery cells  110  included in the battery submodule  100  is not limited thereto, and two or more overlapped-battery cells  110  may be located on both sides of one cooling member  120 . In this case, one battery submodule  100  may include eight battery cells  110 . 
     Each of the plurality of battery submodules  100  may further include at least one cooling member  120  and the fixing frame  130  for fixing and supporting the plurality of battery cells  110 . 
     In this case, the fixing frame  130  may include a first fixing frame  131  for fixing and supporting at least one cooling member  120  so as to be located in parallel to each other, and a second fixing frame  132  which may be located at the outermost side of the battery submodule  100  to be coupled to the first fixing frame  131 , and may fix and support the plurality of battery cells  110  in contact with the at least one cooling member  120  as it is coupled with the first fixing frame  131 . 
     In addition, the second fixing frame  132  may have openings formed at portions in which the plurality of battery cells  110  are located, such that one side of cell bodies  111  of the plurality of battery cells  110 , which is not in contact with the cooling member  120 , may be exposed to the outside through the openings. 
     Specifically, the first fixing frame  131  may fix and support at least two cooling members  120  so that they are located in parallel to each other. At this time, the first fixing frame  131  and the second fixing frame  132  may be made of an insulation material, such that the possibility of electrical communication between the at least two cooling members  120  located in the first fixing frame  131  may be blocked. Thereby, a problem, in which at least two battery cells  110  (i.e., the battery cells  110  on the left and right sides in the drawing) in contact with each of the at least two cooling members  120  are electrically connected with each other through the cooling member  120 , may be blocked. 
     In addition, the first fixing frame  131  may further include one or more terminal parts  1310  which are formed at positions in contact with the electrode tabs  112  of the plurality of battery cells  110 , and respectively include at least one fastening pin  1311 . 
     Specifically, the at least one terminal part  1310  may be formed in the number corresponding to the number of electrode tabs  112  of at least two battery cells  110  located on one side of one battery submodule  100 . Herein, both sides of each terminal part  120  may be electrically connected with the electrode tabs  112  of the battery cells  110  which are located on both sides of the cooling member  120  to face each other through a first bus bar  510  or the like, which will be described below. At this time, the electrode tabs  112  of the battery cells  110  facing each other on both sides of the cooling member  120  may be formed with electrodes having the same polarity as each other and connected in parallel to each other. 
     The fixing frame  130 , to which the first fixing frame  131  and the second fixing frame  132  are coupled, may include at least one beam insertion hole  133  which is formed at a position corresponding to at least one fixed beam  300  to be described below, into which the fixed beam  300  is inserted. 
     As described above, in the battery submodule  100  of the battery rack  1  according to the embodiment of the present invention, double, triple or more battery cells  110  may be located on the same plane. Therefore, the number of the battery cells  110  provided per battery module  10  may be significantly increased compared to the conventional battery rack, and the number of battery modules  10  per battery rack  1  may be reduced from one-half to one-third of the conventional battery rack. Therefore, the energy density of the entire battery rack  1  may be greatly improved. 
       FIG.  5    is a perspective view illustrating a state in which the battery submodule  100  and the fixed beam  300  are coupled in the battery module  10  of the battery rack  1  according to the embodiment of the present invention. At this time, for the convenience of description, only one battery submodule  100  is coupled to the fixed beam  300  as illustrated in  FIG.  5   , but the plurality of battery submodules  100  may be coupled to the fixed beam  300  in the same method with being stacked. 
     Referring to  FIG.  5   , each of the plurality of battery modules  10  included in the battery rack  1  according to the embodiment of the present invention may include at least one fixed beam  300  for fixing and supporting the plurality of stacked battery submodules  100 . At this time, the at least one fixed beam  300  may be inserted into at least one beam insertion hole  133  formed in the fixing frame  130  of the battery submodule  100  to fix and support the battery submodule  100 . Meanwhile, the fixed beam  300  may be formed in a stick shape and may extend in the direction in which the plurality of battery submodules  100  are stacked. At this time, the fixed beam  300  has a cross-section formed with at least one corner such as a rectangular, so that the plurality of battery submodules  100  may be reliably fixed and supported. 
     As described above, the plurality of stacked battery submodules  100  may be fixed to at least one fixed beam  300  to be maintained with being stacked, and may ensure the structural rigidity without a separate case or the like surrounding the outer surface thereof. Accordingly, the entire weight of the battery module  10  is decreased, such that the battery module  10  may be easily transported and installed, as well as costs and time during manufacturing thereof may be reduced. 
     Meanwhile,  FIG.  5    illustrates a case in which six fixed beams  300  are inserted into the beam insertion hole  133  of the battery submodule  100 , but it is not limited thereto, and any number of the fixed beams  300  may be used so long as they can sufficiently maintain the structural rigidity between the plurality of battery submodules  100 . 
     In addition, at least one fixed beam  300  may be fixedly coupled to the front cover unit  210  and the rear cover unit  220 . Each of the plurality of battery modules  10  may include elastic pads  400  each of which is interposed between one or more battery submodules  100  adjacent to each other in the plurality of battery submodules  100 . 
     Thereby, the elastic member may mitigate an expansion of the plurality of battery cells  110  in the battery submodule  100  due to swelling, and may prevent external impact and vibration from being transmitted to the battery cells  110 . Also, since the plurality of battery submodules  100  are fixed in a state in which the front cover unit  210  and the rear cover unit  220  are located on both sides in the stacking direction, it is possible to inhibit the plurality of battery cells  110  from being expanded in the direction in which the plurality of battery submodules  100  are stacked. 
     Meanwhile, it is not limited the configuration in which the elastic members disposed between every battery submodules  100 , and the battery submodules  100  may be disposed between two bundles or three bundles thereof by selecting the number of bundles, as necessary. 
     In addition, the at least one fixed beam  300  may be firmly coupled to the front cover unit  210  and the rear cover unit  220  by bolt and nut fastening, rivet fastening, and the like, but it is merely an example, and it is not limited to a specific fastening method. 
       FIG.  6    is a plan view illustrating an electrical connection structure between the plurality of battery submodules  100  in the battery module  10  of the battery rack  1  according to the embodiment of the present invention, and  FIG.  7    is a perspective view illustrating a bus bar assembly  520  included in the battery module  10  of the battery rack  1  according to the embodiment of the present invention. 
     Referring to  FIGS.  6  and  7   , first, as described above, the battery cells  110 , which are located in one battery submodule  100  and are in contact with the same cooling member  120  to face each other, may be connected to each other in parallel through the first bus bar  510 . At this time, the first bus bar  510  is formed in a “U” shape, and may be electrically connected to the electrode tabs  112  of the battery cell  110  facing each other by laser welding or the like. In this case, the first bus bar  510  may be electrically connected to the electrode tabs  112  with being fastened to the fastening pins  1311  of the terminal part  1310 , thereby facilitating the electrical connection operation. 
     However, the electrical connection method at this time is not limited to laser welding, and ultrasonic welding, soldering, or the like may be used. In addition, it will be obviously appreciated to those skilled in the art that the electrical connection may be performed by using an adhesive such as a bond of a physical fastening method such as screwing. 
     In addition, the first bus bars  510  may be connected to each other in series by a second bus bar  521 . At this time, as illustrated in  FIG.  7   , the second bus bar  521  may be coupled integrally with the bus bar frame  522  to form the bus bar assembly  520 . Since the bus bar frame  522  is made of an insulation material such as plastic, the possibility that the second bus bar  521  is short-circuited may be blocked. 
     Thereby, the operator may simply fasten and couple one bus bar assembly  520  to the fastening pins  1311  formed in the plurality of bus bar submodules  100 , without having to attach the second bus bars  521  one by one for serial connection between the plurality of first bus bars  510 . Therefore, it is possible to minimize risks of short-circuit and safety accidents that may occur during connecting the plurality of submodules  100  in series. However, it will be obviously appreciated to those skilled in the art that the electrical connection between the plurality of first bus bars  510  are not limited to serial connection, but may be connected in parallel. 
     Further, each of the plurality of battery modules  10  included in the battery rack  1  according to the embodiment of the present invention may further include a circuit unit  530  which is connected to the plurality of first bus bars  510  to measure a voltage value to determine a voltage state in the plurality of battery submodules  100 . At this time, the bus bar assembly  520  and the circuit unit  530  may be fastened to the fastening pin  1311  formed in the terminal part  1310 . 
     Specifically, each of the second bus bars  521  of the bus bar assembly  520  may include two fastening holes  5210  formed therein, and the fastening pins  1311  of the terminal part  1310  may be inserted into the fastening holes  5210  of the second bus bar  521 . As illustrated in  FIG.  6   , the bus bar assembly  520  may be located at upper and lower portions of the battery module  10  to be fastened to the uppermost and lowermost fastening pins  1311 , and the circuit unit  530  may be located between the upper and lower bus bar assemblies  520  to be fastened to the upper and lower fastening pins  1311 . 
       FIG.  8    is a perspective view illustrating a state in which the front cover unit  210  is disassembled from the battery module  10  of the battery rack  1  according to the embodiment of the present invention, and  FIG.  9    is a perspective view illustrating a state in which the rear cover unit  220  is disassembled from the battery module  10  of the battery rack  1  according to the embodiment of the present invention. 
     Referring to  FIGS.  8  and  9   , first, as described above, the plurality of battery cells  110  located on each of both sides in the direction in which the plurality of battery submodules  100  are stacked may be connected in series to each other, and the serially-connected plurality of battery cells  110  may be connected in series through the module bus bar  223 . 
     Specifically, the rear cover unit  220  may include a rear plate  221  which is located on the battery submodule  100  side to support the stacked battery submodule  100 , the module bus bar  223 , and a rear cover member  222  which is located outside the module bus bar  223  to protect the module bus bar  223  from the external foreign matters and block the possibility of electrical communication. 
     Thereby, the plurality of battery submodules  100  on both sides in the stacking direction may be connected to each other in series, respectively, and then again connected in series with each other through the module bus bar  223 . 
     Meanwhile, the front cover unit  210  may include a front plate  211  which is located on the battery submodule  100  side to support the stacked battery submodule  100 , a battery management system (BMS) module  214  for controlling the battery module  10 , a high voltage connection member  213  for electrically connecting the first bus bar  510  on the front surface of the battery module  10  on one side of both sides in the direction in which the plurality of battery submodules  100  are stacked and the second terminal  12 , and a front cover member  212  which is located outside the BMS module  214  and the high voltage connection member  213  to protect the same from the external foreign matters. 
     At this time, in the battery rack  1  according to the embodiment of the present invention, the respective BMS modules  214  installed in each of the plurality of battery modules  10  may be connected to each other, and then connected to the battery rack controller  50 . Thereby, the battery rack controller  50  may control the entire battery module  10  through the BMS modules  214  installed in the plurality of battery modules  10 . 
     In addition, a manual service device (MSD) module  215 , which may select whether to apply voltage to the battery module  10  as it is manually opened or closed, may be attached to the high voltage connection member  213 . 
     As described above, the first terminal  11  and the second terminal  12  of the battery module  10  are located together on one side through the high voltage connection member  213  and the like. Therefore, operations for installing the battery rack  1  according to the embodiment of the present invention and connecting the plurality of battery modules  10  may be facilitated, and when installing and transporting the battery module  10 , it is possible to prevent a safety accident due to the first terminal  11  and the second terminal  12  with a high voltage, through the MSD module  215  installed in the high voltage connection member  213 . 
     Meanwhile, the rear plate  221  and the rear cover member  222 , as well as the front plate  211  and the front cover member  212  may be screwed together by bolts or the like, but it is not limited thereto. 
       FIG.  10    is a side view schematically illustrating a state in which the plurality of battery modules  10  disposed in the battery rack  1  according to the embodiment of the present invention are cooled, and  FIG.  11    is a front view illustrating the battery rack  1  according to the embodiment of the present invention. 
     Referring to  FIGS.  10  and  11   , the battery rack  1  according to the embodiment of the present invention may further include a cooling fan  40  located at upper or lower side of the plurality of stacked battery modules  10  to dissipate heat generated from the plurality of battery modules  10 . 
     Specifically, as illustrated in  FIG.  10   , the cooling fan  40  may be located at the uppermost end of the plurality of stacked battery modules  10  to cool the plurality of battery modules  10  inside the housing  20  through intake or exhaust of outside air. At this time, the exposed parts  122  of the cooling member  120  are exposed at the upper and lower surfaces of each of the plurality of battery modules  10 , such that cooling efficiency of the battery module  10  may be increased. 
     That is, each of the plurality of battery cells  110  may be directly cooled by the surface-contacted cooling member  120  therewith, and in this case, the cooling member  120  may be cooled by the outside air introduced into a space (gap) between battery modules  10  adjacent to each other by the cooling fan  40 , thus to be doubly cooled. Therefore, the plurality of battery cells  110  may be effectively cooled. In particular, during cooling, the cooling member  120 , which is exposed to the upper and lower surfaces of each of the battery modules  10 , may be subjected to convective heat transfer by coming into direct contact with coolant such as outside air introduced from the outside. As described above, since the cooling member  120  is exposed to the upper and lower surfaces of the battery module  10 , cooling by the outside air may be performed across a wide area. 
     Meanwhile, the cooling fan  40  may be located at the upper or lower side of the plurality of stacked battery modules  10  with being mounted on the battery rack controller  50 . Further, two or more of the cooling fans  40  may be disposed together on the upper or lower side of the plurality of battery modules  10 . 
     In addition, the plurality of battery modules  10  may be stacked with a predetermined distance d 1  therebetween. At this time, the predetermined distance d 1  may be gradually increased from one side on which the cooling fan  40  is located toward the other side in the direction in which the battery modules  10  are stacked. 
     Specifically, the cooling fan  40  provided in the battery rack  1  according to the embodiment of the present invention is located only on one side of the upper and lower sides of the plurality of battery modules  10 , such that flow rates of the outside air flowing each of the battery modules  10  may vary depending on the position of the cooling fan  40 . However, as described above, since the distance d 1  between the plurality of battery modules  10  is gradually increased from one side on which the cooling fan  40  is installed toward the other side (i.e. d 11 &gt;d 12 &gt;d 13 &gt;d 14 &gt;d 15 &gt;d 16 &gt;d 17 ), the flow rate of the outside air flowing between the adjacent battery modules  10  may be evenly maintained, and the plurality of battery modules  10  may be uniformly cooled. 
     At this time, the distance d 1  between the battery modules  10  is formed in a range of 2 mm to 30 mm, such that the plurality of battery modules  10  may be effectively cooled. 
     Meanwhile, the cooling fan  40  may be located on one side or both sides of a direction in which the battery submodules  100  are stacked at the upper or lower side of the plurality of stacked battery modules  10 . Further, when the cooling fan  40  is located on one side (i.e., in front of or rear of the battery rack  1 ) in the direction in which the plurality of battery submodules  100  are stacked at the upper or lower side of the stacked battery modules  10 , the closed surface  21  on the side in which the cooling fan  40  is located among the peripheral surfaces of the housing  20  perpendicular to the direction in which the plurality of battery modules  10  are stacked may be spaced apart from the plurality of battery modules  10  with a predetermined distance d 2 . 
     That is, as illustrated in  FIG.  10   , the cooling fan  40  may be located on a back side of the battery module  10  at the upper side of the plurality of battery modules  10  together with the battery rack controller  50 , and the closed surface  21  on the back side of the battery module  10 , in which the cooling fan  40  is located among the peripheral surfaces (peripheral surfaces perpendicular to a paper surface in the drawings) perpendicular to the direction in which the plurality of battery modules  10  are stacked in the housing  20 , may be disposed apart from the plurality of stacked battery module  10  with the predetermined distance d 2 . 
     At this time, the closed surface  21  of the housing  20  is formed in a flat plate shape that is not opened, such that it is possible to prevent the outside air flowing into the space between the battery modules  10  on the front surface of the battery rack  1  from escaping to the outside, and define a flow path so that the inflowing outer air flows to the cooling fan side. Meanwhile, the predetermined distance d 2  of the closed surface  21  may be formed in a range of 10 mm to 100 mm, preferably 40 mm, to maximize the cooling efficiency of the plurality of battery modules  10 . 
     Meanwhile, directions of arrows illustrated in the schematic view of  FIG.  10    indicate directions in which the outside air flow, when sucking air inside the battery rack  1  according to the embodiment of the present invention and exhausting it to the outside by the cooling fan  40 . On the other hand, when sucking air outside the battery rack  1  according to the embodiment of the present invention and flowing inside by the cooling fan  40 , the moving direction of the air may be reversely formed. 
     In addition, referring to an enlarged view of  FIG.  10   , it may be seen that heat generated from the battery cell  110  is dissipated to the exposed parts  122  through the contact parts  121  of the cooling member  120 . 
     As described above, the battery rack  1  according to the embodiment of the present invention is located only on one side in the direction in which the plurality of battery modules  10  are stacked, such that the entire plurality of battery modules  10  may be efficiently cooled. Therefore, it is possible to easily control the cooling fan  40 , and significantly reduce installation and maintenance costs compared to a case in which the cooling fan  40  is installed for each of the conventional battery modules  10 . 
       FIG.  12    is an exploded perspective view of a battery submodule  100 ′ included in a battery module  10 ′ of a battery rack according to another embodiment of the present invention, and  FIG.  13    is a perspective view illustrating a battery submodule  100 ′ included in the battery module  10 ′ of the battery rack according to another embodiment of the present invention. 
     Referring to  FIGS.  12  and  13   , a plurality of battery cells  110 ′ of the battery module  10 ′ included in the battery rack according to another embodiment of the present invention may be formed as a bidirectional polarity battery cell  110 ′ having two electrode tabs ( 112 ′) each of which protrudes from both sides of a cell body  111 ′, not the unidirectional polarity battery cells  110  having two electrode taps ( 112 ) which protrude from one side of the cell body  111 . At this time, a structure, in which the cooling member  120  and the battery cell  110 ′ are in contact with each other, may be fixed and supported by a fixing frame  130 ′ formed by coupling a first fixing frame  131 ′ and a second fixing frame  132 ′. 
     Specifically, the plurality of battery cells  110 ′ forming the battery submodule  100 ′ may be formed as the bidirectional polarity battery cell  110 ′. Accordingly, at least one cooling member  120 ′ and the battery cells  110 ′ which are in contact with one side of the cooling member  120 ′ may be arranged side by side on upper and lower sides in a direction in which the battery submodules  100 ′ are stacked. At this time, in a case of the cooling member  120 ′ in contact with the bidirectional polarity battery cell  110 ′, an exposed part  122 ′ may be formed only on one side rather than the exposed part  122 ′ formed on the upper and lower sides of one cooling member  120 ′. At least two cooling members  120 ′ may be located above and below the battery submodule  100 ′. The exposed part  122 ′ of at least one cooling member  120 ′ may form the upper and lower surfaces of the battery module  10 ′. 
     However, even when the exposed part  122 ′ of the cooling member  120 ′ is formed only on one side, since a length of the bidirectional polarity battery cell  110 ′ is formed twice the length of the unidirectional polarity battery cell  110 , the size of the exposed part  122 ′ of the cooling member  120 ′ in contact with the unidirectional polarity battery cell  110  may also be formed twice the size of the exposed part  122  of the cooling member  120 . In addition, since exposed areas of the exposed parts  122  and  122 ′ of the cooling members  120  and  120 ′ per unit battery cell  110  and  110 ′ are similar to the above description, the cooling effect obtained by the cooling member  120 ′ is also similar to that of the battery rack  1  according to the embodiment of the present invention. 
     Contacting, cooling, and like of the cooling member  120 ′ and the battery cell  110 ′ are the same as those of the unidirectional polarity battery cell  110  of the battery rack  1  according to the embodiment of the present invention, and therefore will not be described in detail. 
       FIG.  14    is a perspective view illustrating a state in which the battery submodule  100 ′ and a fixed beam  300 ′ are coupled in the battery module  10 ′ of the battery rack according to another embodiment of the present invention, and  FIG.  15    is a perspective view illustrating a battery module  10 ′ of the battery rack according to another embodiment of the present invention. 
     Referring to  FIGS.  14  and  15   , the plurality of battery submodules  100 ′ may be structurally fixed and supported by the fixed beam  300 ′. At this time, as in the case of the battery rack  1  according to the embodiment of the present invention, elastic pads  400 ′ are interposed between every battery submodules  100 ′ or between every two bundles of the battery submodules  100 ′, thereby it is possible to prevent the plurality of battery cells  110 ′ from being expanded. 
     As described above, the structure and shape for forming the battery module  10 ′ by fixing the plurality of battery submodules  100 ′ are the same as those of the battery rack  1  according to the embodiment of the present invention, and therefore will not be described in detail. 
     Meanwhile, the plurality of battery submodules  100 ′ of the battery rack according to another embodiment of the present invention may also be electrically connected to each other by a bus bar assembly  520 ′. At this time, in the battery module  10 ′ of the battery rack according to another embodiment of the present invention, the battery submodule  100 ′ includes the bidirectional polarity battery cell  110 ′, such that the plurality of battery cells  110 ′ located at the upper side in the drawings may be connected to each other in series, and the plurality of battery cells  110 ′ located on the lower side in the drawing may also be connected to each other in series, thus to be electrically connected with each other through the same configuration as the module bus bar  223 . 
     Meanwhile, the features of a front cover unit  210 ′, a rear cover unit  220 ′, and side cover units  230 ′ of the battery module  10 ′ and the cooling method of the battery rack according to another embodiment of the present invention are the same as those of the battery rack  1  according to the embodiment of the present invention, and therefore will not be described in detail. 
     Although the representative embodiments of the present invention have been described in detail, it will be understood by persons who have a common knowledge in the technical field to which the present invention pertains that various modifications and variations may be made therein without departing from the scope of the present invention. Accordingly, the scope of the present invention should not be limited to the embodiments, but be defined by the appended claims as well as equivalents thereof. 
     DESCRIPTION OF REFERENCE NUMERALS 
       1 : Battery rack 
       10 ,  10 ′: Battery module 
       11 : First terminal 
       12 : Second terminal 
       20 : Housing 
       21 : Closed surface 
       30 : Connecting member 
       40 : Cooling fan 
       50 : Rack controller 
       100 ,  100 ′: Battery submodule 
       110 ,  110 ′: Battery cell 
       111 ,  111 ′: Cell body 
       112 ,  112 ′: Electrode tab 
       120 ,  120 ′: Cooling member 
       121 ,  121 ′: Contact part 
       122 ,  122 ′: Exposed part 
       130 ,  130 ′: Fixing frame 
       131 ,  131 ′: First fixing frame 
       1310 : Terminal part 
       1311 : Fastening pin 
       132 ,  132 ′: Second fixing frame 
       133 : Beam insertion hole 
       200 : Protective cover unit 
       210 ,  210 ′: Front cover unit 
       211 : Front plate 
       212 : Front cover member 
       213 : High voltage connecting member 
       214 : BMS module 
       215 : MSD module 
       220 ,  220 ′: Rear cover unit 
       221 : Rear plate 
       222 : Rear cover member 
       223 : Module bus bar 
       230 ,  230 ′: Side cover unit 
       231 : Grip groove 
       300 ,  300 ′: Fixed beam 
       400 ,  400 ′: Elastic pad 
       510 : First bus bar 
       520 : Bus bar assembly 
       521 : Second bus bar 
       5210 : Fastening hole 
       522 : Bus bar frame 
       530 : Circuit unit 
       600 : Latch screw 
       610 : Latch groove 
     d 1 , d 11 , d 12 , d 13 , d 14 , d 15 , d 16 , d 17 : Distance between battery modules in stacking direction 
     d 2 : Distance between back surface of housing and back surface of battery module