Patent Publication Number: US-2022223965-A1

Title: Battery pack and manufacturing method thereof

Description:
CROSS-CITATION WITH RELATED APPLICATION(S) 
     This application claims the benefit of Korean Patent Application No. 10-2019-0127009 filed on Oct. 14, 2019 with the Korean Intellectual Property Office, the disclosures of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to a battery pack and a method for manufacturing the same, and more particularly, to a battery pack having a simplified structure and a method for manufacturing the same. 
     BACKGROUND ART 
     A secondary battery has attracted much attention as an energy source in various products such as a mobile device and an electric vehicle. The secondary battery is a potent energy resource that can replace the use of existing products using fossil fuels, and is in the spotlight as an environment-friendly energy source because it does not generate by-products due to energy use. 
     Recently, along with a continuous rise of the necessity for a large-capacity secondary battery structure, including the utilization of the secondary battery as an energy storage source, there is a growing demand for a battery pack of a multi-module structure which is an assembly of battery modules in which a plurality of secondary batteries are connected in series/parallel. 
     Meanwhile, when a plurality of battery cells are connected in series/parallel to configure a battery pack, it is common to configure a battery module composed of at least one battery cell, and to configure a battery pack by using at least one of the battery modules and adding other components. 
     Such a battery pack includes an upper case and lower case, a battery module stack in which battery modules are stacked between the upper case and the lower case, and a plurality of tubes for fixing the battery modules of the battery module stack. 
     In conventional indirect water-cooled battery modules, a cooling plate (heat sink) through which liquid refrigerant flows was attached to the lower part of the battery module, and it was usually mounted on the pack tray as only one layer. This is because the battery pack is generally placed low and wide on the floor under the seat space of a passenger car. 
     Recently, electric drive development has been carried out not only for passenger cars but also for commercial vehicles such as trucks. In the case of a truck like this, 
     There is a demand to locate the driving battery in the location where the existing fuel tank was placed (specifically, the space under the cargo compartment on the left and right sides behind the front axle). The battery pack mounted on a commercial vehicle in this way has no choice but to have a rectangular shape with a high height unlike a passenger car. In order to arrange a plurality of battery modules, there is no choice but to arrange the battery modules in multiple layers. At the same time, the position of the battery pack is placed at the outermost part of the vehicle, so that high crush safety is required in consideration of a collision accident. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problem 
     It is an object of the present disclosure to provide a battery pack excellent in compression stability and having a simplified battery module fixing structure, and a method for manufacturing the same. 
     The problem to be solved by the present disclosure is not limited to the above-mentioned problems, and other problems not mentioned should be clearly understood by those skilled in the art from the following description. 
     Technical Solution 
     In order to achieve the above objects, a battery pack according to one embodiment of the present disclosure comprises: an upper case and lower case; a battery module stack in which battery modules are stacked between the upper case and the lower case; a longitudinal square tube formed in the left and right directions of the stacked battery modules and mounted on the battery module stack; a vertical square tube formed in the vertical direction of the stacked battery modules and mounted on the battery module stack; and a horizontal square tube formed in the front and rear directions of the stacked battery modules and mounted on the battery module stack, wherein the longitudinal square tube is formed of a plurality of tubes, and the plurality of longitudinal square tubes are stacked and arranged in the vertical direction between the stacked battery modules so as to be coupled with all of the battery modules formed in the left and right directions at an uppermost part and a lowermost part, wherein the vertical square tubes is formed of a plurality of tubes, and the plurality of vertical square tubes are coupled to all the parts of the longitudinal square tubes respectively located on a plurality of axes of the stacked vertical square tubes among the stacked longitudinal square tubes in the four-direction outer periphery of the battery module stack, and wherein the horizontal square tubes is formed of a plurality of tubes, and the plurality of horizontal square tubes are coupled to all the parts of each of the vertical square tubes respectively located on a plurality of axes of the plurality of vertical square tubes, from the outside of the plurality of vertical square tubes. 
     In order to achieve the above objects, a method for manufacturing a battery pack according to one embodiment of the present disclosure includes: the steps of: stacking and arranging a plurality of longitudinal square tubes mounted on the battery module stack in a vertical direction between the stacked battery modules so as to be coupled integrally with the battery modules formed in the left and right directions at the uppermost part and the lowermost part; coupling a plurality of vertical square tubes with all of the longitudinal square tubes respectively located on a plurality of longitudinal axes of the stacked longitudinal square tubes in the four-direction outer periphery of the battery module stack; and in the outside of the plurality of vertical square tubes, coupling a plurality of horizontal square tubes with all of the parts of the vertical pipes respectively located on a plurality of axes in the front and rear directions among the plurality of vertical square tubes. 
     The plurality of longitudinal square tubes may include: a plurality of first longitudinal square tubes formed at both ends of the lowermost parts of the stacked battery modules; 
     at least one second longitudinal square tube formed between the plurality of first longitudinal square tubes at the lowermost parts of the stacked battery modules; a plurality of third longitudinal square tubes formed at both ends of a plurality of longitudinal square tubes formed between the uppermost part of the stacked battery modules and the stacked battery modules; and at least one fourth longitudinal square tube formed between the plurality of third longitudinal square tubes excluding the plurality of third longitudinal square tubes formed on the uppermost part of the stacked battery modules. 
     The battery pack may include a heat sink formed between the battery modules and the plurality of longitudinal square tubes, and a heat sink insulator that is arranged between the heat sink and a battery module located below the heat sink so that the heat sink is into close contact with the battery module. 
     The plurality of first longitudinal square tubes and the plurality of third longitudinal square tubes may be coupled to the heat sink. 
     Connecting parts are formed on both sides of the plurality of first longitudinal square tubes and the plurality of third longitudinal square tubes, and the plurality of first longitudinal square tubes or the plurality of third longitudinal square tubes may be coupled to the heat sink via the connecting part. 
     The at least one second longitudinal square tube and the at least one fourth longitudinal square tube may have a cut-out part formed therein, and the heat sink is inserted into the cut-out part. 
     The heat sink insulator includes a first heat sink insulator formed in the center; and second and third heat sink insulators formed on both sides, the second longitudinal square tubes are formed of two or more tubes, the first heat sink insulator is formed between the plurality of second longitudinal square tubes and between the plurality of fourth longitudinal square tubes, and the second and third heat sink insulators are formed between the first longitudinal square tubes at both ends and the second longitudinal square tubes closest to each other, and between the third vertical square tube at both ends and the fourth longitudinal square tubes closest to each other. 
     The battery pack further includes a cooling water pipe for supplying cooling water to the heat sink, wherein the cooling water pipe is formed on one surface of the battery module stack. 
     A tongs part is formed on one side of the heat sink insulator, and the cooling water pipe may be fixed through the tongs part. 
     A support portion supporting the battery module stack and coupled to the lower case may be formed in the plurality of first longitudinal square tubes and the at least one second longitudinal square tube. 
     The plurality of vertical square tubes may include a plurality of first vertical square tubes which are coupled to one of the plurality of first longitudinal square tube, and the plurality of third longitudinal square tubes located on the same vertical axis as one of the plurality of first longitudinal square tubes; and a plurality of second vertical square tubes which are coupled to one of the plurality of second longitudinal square tubes, and one of the plurality of fourth longitudinal square tubes and the third longitudinal square tubes located on the same vertical axis as one of the plurality of second longitudinal square tubes. 
     A plurality of longitudinal square tube connecting parts are formed on one side of the first vertical square tube, and the plurality of longitudinal square tube connecting parts may be coupled to a first longitudinal square tube connecting part formed on one of the plurality of first longitudinal square tubes, and a first longitudinal square tube connecting part formed on the plurality of third longitudinal square tubes located on the same vertical axis as one of the plurality of first longitudinal square tubes. 
     A plurality of longitudinal square tube connecting parts are formed on one side of the second vertical square tube, and the plurality of v longitudinal square tube connecting parts may be coupled to a second longitudinal square tube connecting part formed on one of the plurality of second longitudinal square tubes, a second longitudinal square tube connecting part formed on the plurality of fourth longitudinal square tubes located on the same vertical axis as one of the plurality of fourth longitudinal square tubes, and a second longitudinal square tube connecting parts formed on one of the plurality of third longitudinal square tubes. 
     The plurality of vertical square tubes include a plurality of second longitudinal square tubes that are coupled to one of the plurality of first longitudinal square tubes, and a plurality of third longitudinal square tubes located on the same vertical axis as one of the plurality of first longitudinal square tubes, a plurality of longitudinal square tube connecting parts are formed on one side of the second longitudinal square tube, the plurality of longitudinal square tube connecting parts are coupled to a second longitudinal square tube connecting part formed on one of the plurality of first longitudinal square tubes, and a second longitudinal square tube connecting parts formed on the plurality of third longitudinal square tubes located on the same vertical axis as one of the plurality of first longitudinal square tubes. 
     The plurality of horizontal square tubes may be coupled to the plurality of second longitudinal square tubes located coaxially in the front and rear directions. 
     A plurality of vertical square tube connecting parts may be formed in the plurality of horizontal square tubes, and the plurality of vertical square tube connecting parts may be coupled to the horizontal square tube connecting part is formed in the plurality of second vertical square tubes. 
     The battery pack may further include a plurality of brackets fixing the battery module stack to the lower case. 
     The method may further include the steps of: fixing the battery module stack to the lower case via a bracket and coupling the upper case to the lower case, after the step of combining the plurality of horizontal square tubes. 
     Advantageous Effects 
     The battery pack and its manufacturing method according to an embodiment of the present disclosure improve the compression stability of the battery modules and at the same time, provide weight reduction and price competitiveness, by fixing the stacked battery modules using most simplified square tubes. 
     The effects of the present disclosure are not limited to the effects mentioned above and additional other effects not described above will be clearly understood from the description of the appended claims by those skilled in the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating first and second longitudinal square tubes and a heat sink insulator according to an embodiment of the present disclosure. 
         FIG. 2  is a perspective view illustrating the assembled configuration of  FIG. 1  and a heat sink and battery modules according to an embodiment of the present disclosure. 
         FIG. 3  is a perspective view illustrating a state in which a plurality of battery modules are stacked together with a plurality of longitudinal square tubes according to an embodiment of the present disclosure. 
         FIG. 4  is a top view (a), a perspective view (b), and a side view (c) of a first longitudinal square tube according to an embodiment of the present disclosure. 
         FIG. 5  is a top view (a), a perspective view (b), and a side view (c) of a second longitudinal square tube according to an embodiment of the present disclosure. 
         FIG. 6  is a top view (a), a perspective view (b), and a side view (c) of a third longitudinal square tube according to an embodiment of the present disclosure. 
         FIG. 7  is a top view (a), a perspective view (b), and a side view (c) of a fourth longitudinal square tube according to an embodiment of the present disclosure. 
         FIG. 8  is a view illustrating a state in which each longitudinal square tube is coupled to the battery module stack according to an embodiment of the present disclosure. 
         FIG. 9  is a view illustrating the configuration of  FIG. 8  and a plurality of vertical square tubes according to an embodiment of the present disclosure. 
         FIG. 10  is a top view (a), a perspective view (b), and a side view (c) of a first vertical angle tube according to an embodiment of the present disclosure. 
         FIG. 11  is a top view (a), a perspective view (b), and a side view (c) of a second vertical angle tube according to an embodiment of the present disclosure. 
         FIG. 12  is a view illustrating a state in which a plurality of vertical square tubes are coupled to the battery module stack of  FIG. 9 . 
         FIG. 13  is a view illustrating the configuration of  FIG. 12  and horizontal square tubes according to an embodiment of the present disclosure. 
         FIG. 14  is a top view (a), a perspective view (b), and a side view (c) of horizontal square tubes according to an embodiment of the present disclosure. 
         FIG. 15  is a view illustrating a state in which a plurality of horizontal square tubes are coupled to the battery module stack of  FIG. 12 . 
         FIG. 16  is a view illustrating a state in which BMS and BDU are coupled to a battery module stack according to an embodiment of the present disclosure. 
         FIG. 17  is a front view of  FIG. 16 . 
         FIG. 18  is a rear view of  FIG. 16 . 
         FIG. 19  is a top view of  FIG. 16 . 
         FIG. 20  is a cross-sectional view illustrating a portion A-A′ of  FIG. 19 . 
         FIG. 21  is a view illustrating a battery module stack, upper and lower cases, and brackets according to an embodiment of the present disclosure. 
         FIG. 22  is a view illustrating a lower case according to an embodiment of the present disclosure. 
         FIG. 23  is a view illustrating a state in which the upper and lower cases are assembled according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     It should be appreciated that the exemplary embodiments, which will be described below, are illustratively described to help understand the present disclosure, and the present disclosure may be variously modified to be carried out differently from the exemplary embodiments described herein. However, in the description of the present disclosure, the specific descriptions and illustrations of publicly known functions or constituent elements will be omitted when it is determined that the specific descriptions and illustrations may unnecessarily obscure the subject matter of the present disclosure. In addition, to help understand the present disclosure, the accompanying drawings are not illustrated based on actual scales, but parts of the constituent elements may be exaggerated in size. 
     As used herein, terms such as first, second, and the like may be used to describe various components, and the terms are used only to discriminate one component from another component. 
     Further, the terms used herein are used only to describe exemplary embodiments, and are not intended to limit the present disclosure. A singular expression includes a plural expression unless they have definitely opposite meanings in the context. It should be understood that the terms “comprise”, “include”, and “have” as used herein are intended to designate the presence of stated features, numbers, steps, operation, constitutional elements, or combinations thereof, but it should be understood that they do not preclude a possibility of existence or addition of one or more other features, numbers, steps, operation, constitutional elements, or combinations thereof. 
     The order of the figures corresponding to the content of the invention described later shows the process for assembling the battery pack according to an embodiment of the present disclosure in order. Further, the arrangement directions of the components forming the present disclosure described later will be described in the directions corresponding to the front and rear directions, the left and right directions, and the up and down directions shown in  FIG. 15  which is a representative figure. The reference of the directions is in accordance with the arrangement direction of the battery modules of the present disclosure. 
     Hereinafter, referring mainly to  FIGS. 1 to 8 , the longitudinal square tube and the peripheral configuration connected to the longitudinal square tube according to an embodiment of the present disclosure will be described.  FIG. 1  is a perspective view illustrating first and second longitudinal square tubes and a heat sink insulator according to an embodiment of the present disclosure.  FIG. 2  is a perspective view illustrating the assembled configuration of  FIG. 1  and a heat sink and battery modules according to an embodiment of the present disclosure.  FIG. 3  is a perspective view illustrating a state in which a plurality of battery modules are stacked together with a plurality of longitudinal square tubes according to an embodiment of the present disclosure.  FIG. 4  is a top view (a), a perspective view (b), and a side view (c) of a first longitudinal square tube according to an embodiment of the present disclosure.  FIG. 5  is a top view (a), a perspective view (b), and a side view (c) of a second longitudinal square tube according to an embodiment of the present disclosure.  FIG. 6  is a top view (a), a perspective view (b), and a side view (c) of a third longitudinal square tube according to an embodiment of the present disclosure.  FIG. 7  is a top view (a), a perspective view (b), and a side view (c) of a fourth longitudinal square tube according to an embodiment of the present disclosure.  FIG. 8  is a view illustrating a state in which each longitudinal square tube is coupled to the battery module stack according to an embodiment of the present disclosure. 
     First, referring to  FIG. 8 , the overall arrangement of a plurality of longitudinal square tubes will be described. 
     A plurality of longitudinal square tubes  300  are formed in the front and rear directions of the stacked battery modules  210  and are mounted on the battery module stack  200 , and stacked and arranged vertically between the stacked battery modules  210  so as to be coupled with both the battery modules  210  formed in the left and right directions of the uppermost part and the lowermost part. 
     A plurality of longitudinal square tubes  300  for fixing the plurality of battery modules  210  of the battery module stack  200  may include a plurality of first longitudinal square tubes  310  formed at both (or opposite) ends of the lowermost parts of the stacked battery modules  210 , at least one second longitudinal square tube  320  formed between the plurality of first longitudinal square tubes  310  at the lowermost part of the stacked battery modules  210 , a plurality of third longitudinal square tubes  330  formed at the uppermost part of the stacked battery modules  210  and both ends of the plurality of longitudinal square tubes  300  formed between the stacked battery modules, and at least one fourth longitudinal square tube  340  formed between the plurality of third longitudinal square tubes  330  excluding the plurality of third longitudinal tubes  330  formed at the uppermost part of the stacked battery modules. 
     According to an embodiment of the present disclosure, the second longitudinal square tubes  320  can be arranged as two second longitudinal square tubes  320  maintaining the same distance as the first longitudinal square tubes  310  at both ends, between the first longitudinal square tubes  310  located at the lower part of both ends of the battery module stack  200 . 
     Also, according to an embodiment of the present disclosure, the fourth longitudinal square tubes  340  may be arranged as two fourth longitudinal square tubes  340  maintaining the same distance as the third longitudinal square tubes  330  at both ends, between the two third longitudinal square tubes  330  located on the same plane among the plurality of third longitudinal square tubes  330  formed at both ends of the battery module stack  200 . Further, the fourth longitudinal square tubes  340  may be stacked and arranged two by two in the vertical direction between the third longitudinal square tubes  330  so as to correspond to the vertically stacked positions of the plurality of third longitudinal square tubes  330  located at both ends of the lower part of each of the stacked battery modules  210 . 
     According to an embodiment of the present disclosure, the battery modules  210  are stacked and arranged in four stages in the vertical direction. The third longitudinal square tubes  330  at both ends of each of the four-stage battery module  210  layers, and two fourth longitudinal square tubes  340  arranged so as to maintain a constant distance with the third longitudinal square tubes  330  between the third longitudinal square tubes  330 , may be stacked and arranged in four stages. 
     Hereinafter, referring mainly to  FIGS. 1 and 2 , the arrangement of the heat sink  600  and the heat sink insulator  610  according to an embodiment of the present disclosure will be described. 
     Referring to  FIGS. 1 and 2 , the battery module  210  according to an embodiment of the present disclosure may have a structure in which a plurality of battery modules  210  are coupled in a horizontal direction. According to an embodiment of the present disclosure, the two battery modules  210  may be coupled in a direction perpendicular to the lengthwise direction of the battery module  210 . As described above, the two battery modules  210  may be stacked and disposed in the vertical direction to form the battery module stack  200 . 
     Referring to  FIG. 2 , a heat sink  600  may be arranged at the lower part of the battery modules  210  according to an embodiment of the present disclosure. In addition, a first longitudinal square tube  310  for fixing the heat sink insulator  610  and the heat sink insulator  610  may be disposed at the lower part of the heat sink  600 . 
     The heat sink  600  may be formed between the battery modules  210  and the plurality of longitudinal square tubes  300 . The battery module according to the present disclosure is an indirect water cooling module, and may cool heat generated from the battery module via a heat sink  600  located under the battery module. Therefore, the heat sink  600  may be disposed in close contact with the lower part of the battery modules  210 . 
     Connecting parts  601  may be formed at both ends of the heat sink  600 . As shown in  FIG. 2 , the connecting part  601  may be coupled with the connecting part  311  formed in the first longitudinal square tube  310 . According to an embodiment of the present disclosure, the connecting parts  601  may be formed two by two at both ends of the heat sink  600 , and the connecting part  311  formed in the first longitudinal square tubes  310  is also formed in two on both sides. The connecting part  601  of the heat sink  600  and the connection part  311  of the first longitudinal square tube  310  may be coupled to each other. At this time, in order to suppress the flow in the plane of the heat sink  600 , the connecting part  311  of the first longitudinal square tube  310  and the connecting part  601  of the heat sink  600  may be fastened and fixed with bolts and nuts. 
     According to an embodiment of the present disclosure, two battery modules  210  are stacked and arranged in the vertical direction, and the heat sink  600  may be arranged at the lower part of the two battery modules  210  formed on each layer. Therefore, the heat sinks  600  are disposed at the lower part of the battery modules  210  stacked in the vertical direction so as to be in close contact with each other, thereby cooling heat generated from all the battery modules  210 . 
     The configuration of the heat sink  600  formed at the lower part of the battery modules  210  shown in  FIG. 2  and the first longitudinal square tube  310  may be equally applied to the structure of the battery module  210  that is stacked and arranged upward as shown in  FIG. 3 . However, in the structure stacked upwards, a third longitudinal square tube  330  may be formed at a position of the first longitudinal square tube  310  as shown in  FIG. 3 . 
     Therefore, in addition to the heat sink  600  formed under the battery modules  210  formed at the lowermost part, the connection parts  601  as shown in  FIG. 2  are formed even at both ends of the heat sinks  600  formed at the lower part of each of the battery modules  210  stacked upward, wherein the connecting part  601  may be coupled to the connecting part  331  formed in the third longitudinal square tube  330  shown in  FIG. 6 . According to an embodiment of the present disclosure, the connecting part  601  of the heat sinks  600  formed above the bottom battery modules  210  is also formed in the same structure as the heat sink  600  formed below the bottom battery module  210 . The connecting parts  331  formed on the third longitudinal square tubes  330  are also formed in two on both sides, so that the connecting parts  601  of the heat sink  600  and the connecting parts  331  of the third longitudinal square tubes  330  can be coupled with each other for each layer. Similarly, in order to suppress the flow in the plane of the heat sink  600 , the connecting parts  331  of the third longitudinal square tube  330  and the connecting part  601  of the heat sink  600  may be fastened and fixed with bolts and nuts. 
     The second longitudinal square tube  320  may be arranged below the central part of the heat sink  600 . Referring to  FIG. 5 , a cut-out part  323  is formed in the central part of the second longitudinal square tube  320 , and the central part of the heat sink  600  may be inserted into the cut-out part  323  and fixed by the second longitudinal square tube  320 . 
     The configurations of the heat sink  600  and the second longitudinal square tube  320  shown in  FIG. 2  may be similarly applied to the structure of the battery module  210  that is stacked on the upper side as shown in  FIG. 3 . However, in the structure stacked on the upper side, a fourth longitudinal square tube  340  may be formed at a position of the second longitudinal square tube  320  as shown in  FIG. 3 . 
     The heat sink insulator  610  may be arranged between the heat sink  600  and the battery modules  210  located below the heat sink  600 , so that the heat sink  600  may be in close contact with the battery module  610 . The heat sink insulator  610  may be formed of plastic having excellent electrical insulation and thermal insulation performance. 
     The plurality of square tubes according to an embodiment of the present disclosure is required to have a certain thickness for assembling bolts and nuts. In order to minimize the stacking height of the battery modules, the thickness of the heat sink may be thinner than that of the plurality of square tubes in the process of forming the heat sink to be thinner. 
     As the thickness of the heat sink becomes thinner than the thickness of the square tube in this way, there may be a gap between the battery modules and the heat sink. Thus, to reduce the gap between the bottom of the battery module and the heat sink, the heat sink insulator  610  is arranged at the lower part of the heat sink  600 , so that the heat sink  600  can be in close contact with the battery modules  210 . 
     According to an embodiment of the present disclosure, the thickness of the heat sink  600  is 10 mm including a thermal pad, the thickness of the heat sink insulator  610  is 15 mm, and the thickness of the square tube is 25 mm. Through this, it can be seen that the space in which the thickness of the square tube is formed can be filled through the heat sink  600  and the heat sink insulator  610 . 
     The heat sink insulator  610  may include a first heat sink insulator  611  formed in the center and second and third heat sink insulators  612  and  613  formed on both sides. The first heat sink insulator  611  may be formed between the plurality of second longitudinal square tubes  320 , and the second and third heat sink insulators  612  and  613  may be formed between the plurality of second longitudinal square tubes  320  and the first longitudinal square tubes  310  at both ends. 
     According to an embodiment of the present disclosure, as shown in  FIG. 2 , the first heat sink insulator  611  may be formed between the two second longitudinal square tubes  320 , and the second and third heat sink insulators  612  and  613  may be formed between a first longitudinal square tube  310  formed at both ends of the battery module stack  200  and a second longitudinal square tube  320  closest to each of the first longitudinal square tube  310 . 
     The configuration of the heat sink insulator  610  formed at the lower part of the heat sink  600  and the first and second longitudinal square tubes  310  and  320  as shown in  FIG. 2  may be similarly applied to the structure of the battery module  210  that is stacked and disposed on the upper side. However, in the structure stacked on the upper side, a third longitudinal square tube  330  may be formed at a position of the first longitudinal square tube  310 , and a fourth longitudinal square tube  340  may be formed at a position of the second longitudinal square tube  320 . 
     More specifically, as shown in  FIG. 3 , the first heat sink insulator  611  may be formed between the two fourth longitudinal square tubes  340 , and the second and third heat sink insulators  612  and  613  may be formed between the third longitudinal square tubes  330  formed at both ends of the battery module stack  200 , and the fourth longitudinal square tube  340  closest to each of the third longitudinal square tubes  330 . 
     A tongs part  610   a  is formed at one end of the heat sink insulator  610  to fix a cooling water pipe described later. The arrangement structure of the heat sink insulator  610 , the heat sink  600 , and the first and third longitudinal square tubes  310  and  330  can also be confirmed by the cross section shown in  FIG. 20 . 
     Hereinafter, the structure of the first to fourth longitudinal square tubes according to an embodiment of the present disclosure will be described with reference mainly to  FIGS. 4 to 7 . 
     Referring to  FIG. 4 , the first longitudinal square tube  310  may include a connecting part  311  coupling with the connecting part  601  of the heat sink  600 , first vertical square tube connecting parts  312  and  313  connected to the first vertical square tube  410 , second vertical square tube connecting parts  314  and  315  connected to the second vertical square tube  420 , and a support part  316  that supports the entire battery module stack  200  and at the same time, couples with the longitudinal square tube connecting part  122  of the lower case  120  shown in  FIG. 22 . 
     According to another embodiment of the present disclosure, the first longitudinal square tube  310  may include the  1 - 1  vertical square tube connecting parts  317  and  318  together with the first vertical square tube connecting parts  312  and  313 . Through this, as shown in  FIG. 12 , the first vertical angle pipe  410  may be respectively coupled to the first vertical square tube connecting parts  312  and  313  as shown in  FIG. 12 , and the first vertical square tube  410  may be coupled with the  1 - 1  vertical square tube connecting parts  317  and  318  as shown in  FIG. 18 . 
     The connecting part  311  may be formed in grooves formed on both sides of the first longitudinal square tube  310 , respectively. The groove is a space formed by removing two adjacent two surfaces of the square tube, and the connecting part  311  is formed on one of the two unremoved surfaces of the groove and may be coupled to the connecting part  601  of the heat sink  600  inserted into the groove. The connecting pars  311  formed on both sides may be formed in parallel. 
     The first vertical square tube connecting parts  312  and  313  and the  1 - 1  vertical square tube connecting parts  317  and  318  may be formed on the remaining surface of the groove on which the connecting part  311  is not formed. The first vertical square tube connecting parts  312  and  313  and the  1 - 1  vertical square tube connecting parts  317  and  318  may be formed in parallel, respectively. The first vertical square tube connecting part  312  may be formed outside the  1 - 1  vertical square tube connecting part  317 , and the first vertical square tube connecting part  313  may also be formed outside the  1 - 1  vertical square tube connecting part  318 . 
     The second vertical square tube connecting parts  314  and  315  may be formed at both ends of one surface of the first longitudinal square tube  310  and coupled to the second vertical square tube  420 , respectively. 
     Both ends of the first longitudinal square tube  310  may be formed to be cut in the oblique direction. The oblique direction formed at one end of the first longitudinal square tube  310  and the oblique direction formed at the other end may be symmetrically formed. One surface of both ends of the first longitudinal square tube  310  may form a support part  316  which is protruded perpendicularly to the lengthwise direction of the first longitudinal square tube  310 . 
     Referring to  FIG. 5 , the second longitudinal square tube  320  may include second vertical square tube connecting parts  321  and  322  connected to the second vertical square tube  420 , a cut-out part  323  into which the heat sink  600  is inserted, and a support portion  324  that supports the entire battery module stack  200  and at the same time couples with the longitudinal square tube connecting part  122  of the lower case  120  shown in  FIG. 22 . 
     The second vertical square tube connecting parts  321  and  322  are formed on both ends of one side of the second longitudinal square tube  320 , and may be coupled with the second vertical square tube  420  as shown in  FIG. 12 . The cut-out part  323  is formed in the center of the second longitudinal square tube  320 , and a part of the plate-shaped heat sink  600  may be inserted into the cut-off space. 
     Both ends of the second longitudinal square tube  320  may be formed to be cut in the oblique direction. The oblique direction formed at one end of the second longitudinal square tube  320  and the oblique direction formed at the other end may be formed symmetrically to each other. One surface of both ends of the second longitudinal square tube  320  may form a support portion  324  which is protruded perpendicular to the lengthwise direction of the second longitudinal square tube  320 . 
     Referring to  FIG. 6 , the third longitudinal square tube  330  may include a connecting part  331  coupled with the connecting part  601  of the heat sink  600 , first vertical square tube connecting parts  332  and  333  connected to the first longitudinal square tube  410 , and second vertical square tube connecting parts  334  and  335  connected to the second vertical square tube  420 . 
     According to another embodiment of the present disclosure, the third longitudinal square tube  330  may include the  1 - 1  vertical square tube connecting parts  336  and  337  together with the first vertical square tube connecting parts  332  and  333 . Through this, the first vertical square tube  410  may be coupled to the first vertical square tube connecting parts  332  and  333 , respectively, as shown in  FIG. 12 , and the first vertical square tube  410  may be coupled to the  1 - 1  vertical square tube connecting parts  336  and  337  as shown in  FIG. 18 . 
     The connecting parts  331  may be formed in grooves formed on both sides of the third longitudinal square tube  330 , respectively. The groove is a space formed by removing two adjacent surfaces on both sides of the square tube, and the connecting part  331  is formed on one of the two unremoved surfaces of the groove, and may be coupled to the connecting part  601  of the heat sink  600  inserted into the groove. Further, as shown in  FIG. 20 , it may be coupled with the BMS  700  and BDU  800  located at the uppermost part of the battery module stack  200 . The connecting parts  311  formed on both sides may be formed in parallel. 
     The first vertical squire tube connecting parts  332  and  333  and the  1 - 1  vertical square tube connecting parts  336  and  337  may be formed on the remaining surface of the groove on which the connecting part  331  is not formed. The first vertical square tube connecting parts  332  and  333  and the  1 - 1  vertical square tube connecting parts  336  and  337  may be formed in parallel, respectively. The first vertical square tube connecting part  332  may be formed outside the  1 - 1  vertical square connecting part  336 , and the first vertical square tube connecting part  333  may also be formed outside the second vertical square tube connecting part  337 . 
     The second vertical square tube connecting portions  334  and  335  are formed on both ends of one surface of the third longitudinal square tube  330  and may be coupled to the second vertical square tube  420 , respectively. 
     Both ends of the third longitudinal square tube  330  may be formed to be cut in an oblique direction. The oblique direction formed at one end of the third vertical square tube  330  and the oblique direction formed at the other end may be formed symmetrically to each other. 
     Referring to  FIG. 7 , the fourth longitudinal square tube  340  may include second vertical square tube connecting parts  341  and  342  connected to the second vertical longitudinal square tube  420 , and a cut-out part  343  into which the heat sink  600  is inserted. The second vertical square tube connecting parts  341  and  342  are formed on both ends of one surface of the fourth longitudinal square tube  340 , and may be coupled with the second vertical square tube  420  as shown in  FIG. 12 . The cut-out part  343  is formed in the center of the fourth longitudinal square tube  340 , and a part of the plate-shaped heat sink  600  may be inserted in the cut-out space. 
     Both ends of the fourth longitudinal square tube  340  may be formed to be cut in the oblique direction. The oblique direction formed at one end of the fourth longitudinal square tube  340  and the oblique direction formed at the other end may be formed symmetrically with each other. 
     Hereinafter, the structure and arrangement of the vertical square tube according to an embodiment of the present disclosure will be described with reference to  FIGS. 9 to 12 . 
       FIG. 9  is a view illustrating the configuration of  FIG. 8  and a plurality of vertical square tubes according to an embodiment of the present disclosure.  FIG. 10  is a top view (a), a perspective view (b), and a side view (c) of a first vertical angle tube according to an embodiment of the present disclosure.  FIG. 11  is a top view (a), a perspective view (b), and a side view (c) of a second vertical angle tube according to an embodiment of the present disclosure.  FIG. 12  is a view illustrating a state in which a plurality of vertical square tubes are coupled to the battery module stack of  FIG. 9 . 
     First, the configuration and arrangement of the vertical square tube according to an embodiment of the present disclosure will be described with reference mainly to  FIGS. 9 and 12 . 
     Referring to  FIGS. 9 and 12 , a plurality of vertical square tube  400  according to an embodiment of the present disclosure are formed in the vertical direction of the stacked battery modules  210 , and are mounted on the battery module stack  200 , and coupled with all parts of the stacked longitudinal square tubes  300  located on a plurality of axes in the vertical direction among the stacked longitudinal square tubes  300 , in the four-direction outer periphery of the battery module stack  200 . 
     The battery module stack  200  and the plurality of longitudinal square tube  400  for fixing the plurality of longitudinal square tubes  300  formed on the battery module stack  200  may include a plurality of first vertical square tubes that are all coupled to one of the first longitudinal square tubes  310  and a plurality of third longitudinal square tubes  330  located on the same vertical axis as one of the plurality of first longitudinal square tubes  310 , and a plurality of second vertical square tubes, all of which are all coupled with one of the second vertical pipes  320 , and a plurality of second vertical square tubes  420 , all of which are coupled with the plurality of fourth longitudinal square tubes  340  located on the same vertical axis as one of the plurality of second longitudinal square tubes  320 . 
     The first vertical square tube  410  may be integrally coupled with one of the plurality of first longitudinal square tubes  310  and the plurality of third longitudinal square tubes  330  located on the same vertical axis as one of the plurality of first longitudinal square tubes  310 . 
     The first vertical square tube  410  has a plurality of longitudinal square tube connecting parts formed on one side, and the plurality of longitudinal square tube connecting parts may be coupled with first vertical square tube connecting parts  312  and  313  formed on one of the plurality of first longitudinal square tubes  310 , and first vertical square tube connecting parts  332  and  333  formed on a plurality of third longitudinal square tubes  330  located on the same vertical axis as one of the plurality of first longitudinal square tube. 
     According to an embodiment of the present disclosure, as illustrated in  FIGS. 9 and 12 , the first vertical square tubes  410  may be formed in the front and rear directions of the battery modules  210 , respectively. In more detail, the first vertical square tube  410  may be formed two by two on front and rear sides of the battery modules  210 . 
     According to an embodiment of the present disclosure, one of the first vertical square tubes  410  on one side can be integrally coupled with the first vertical square tube connecting part  312  formed on the first longitudinal square tube  310  at the lower part on one side, and four first vertical square tube connecting parts  332  formed on the third longitudinal square tubes  330  at the upper part on one side. At this time, the first vertical square tube connecting part  312  and the four first vertical square tube connecting parts  332  are located on the same axis in the vertical direction, so that the first vertical square tube  410  formed in a straight shape is integrally coupled with each connecting part. 
     In addition, according to an embodiment of the present disclosure, one of the first vertical square tube  410  at the lower part on one side may be integrally coupled with a first vertical square tube connecting part  313  formed on the first longitudinal square tube  310  at the upper part on one side, and four first vertical square tube connecting parts  333  formed on the third longitudinal square tubes  330  on one side. At this time, the first vertical square tube connecting part  313  and the four first vertical square tube connecting parts  333  are located on the same axis in the vertical direction, so that the first vertical square tube  410  formed in a straight shape can be integrally coupled with the respective connecting parts. 
     In addition, according to another embodiment of the present disclosure, as shown in  FIG. 18 , one of the first vertical square tubes  410  at the lower part on one side may be integrally coupled with the  1 - 1  vertical square tube connecting part  317  formed on the first longitudinal square tube  310  at the upper part on one side, and four first vertical square tube connecting parts  336  formed on the third longitudinal square tubes  330  on one side. At this time, the first vertical square tube connecting part  317  and the four first vertical square tube connecting parts  336  are located on the same axis in the vertical direction, so that the first vertical square tube  410  formed in a straight shape can be integrally coupled with the respective connecting parts. 
     Further, according to another embodiment of the present disclosure, as shown in  FIG. 18 , one of the first vertical square tubes  410  at the lower end on one side may be integrally coupled with the  1 - 1  vertical square tube connecting part  318  formed in the first longitudinal square tube  310  at the upper end on one side and the third longitudinal square tube  330  on one side, and the four first vertical square tube connecting parts  337 . At this time, the first vertical square tube connecting part  318  and the four first vertical square tube connecting parts  337  are located on the same axis in the vertical direction, and the first vertical square tubes  410  formed in a straight shape may be integrally coupled with the respective connecting parts. 
     The second vertical square tube  420  can be coupled with one of the a plurality of fourth longitudinal square tubes  340  and the third longitudinal square tube  330  located on the same vertical axis as one of the plurality of second vertical longitudinal square tube  320  and one of the plurality of second longitudinal square tube  320 . 
     The second vertical square tube  420  has a plurality of longitudinal square tube connecting parts formed on one side, and the plurality of longitudinal square tube connecting parts can be coupled with the second vertical square tube connecting parts  321   322  formed on one of the plurality of second longitudinal square tubes  320 , the second vertical square tube connecting parts  341  and  342  formed on a plurality of fourth longitudinal square tubes  340  located on the same vertical axis as one of the plurality of fourth longitudinal square tubes, and the second vertical square tube connecting part is  334  and  335  formed on one of the plurality of third longitudinal square tubes  330 . 
     According to an embodiment of the present disclosure, as shown in  FIGS. 9 and 12 , the second vertical square tubes  420  may be formed in the left and right directions of the battery modules  210 , respectively. In more detail, the second vertical square tubes  420  may be formed four by four on the left and right sides of the battery modules  210 , respectively. 
     According to an embodiment of the present disclosure, one of the second vertical square tubes  420  on one side may be integrally coupled with the second vertical square tube connecting part  321  formed on the second longitudinal square tube  320  at the lowermost part on one side, the three second vertical square tube connecting parts  341  formed on the fourth longitudinal square tubes  340  in the center of one side, and the second vertical square tube connecting parts  334  formed on the third longitudinal square tube  330  on the uppermost part on one side. At this time, the second vertical square tube connecting part  321 , the three second vertical square tube connecting part  341  and the second vertical square tube connecting part  334  are located on the same axis in the vertical direction, so that the second vertical square tubes  420  formed in a straight shape may be integrally coupled with the respective connecting parts. 
     According to an embodiment of the present disclosure, one of the second vertical square tubes  420  on one side can be integrally coupled with the second vertical square tube connecting part  322  formed on the second longitudinal square tube  320  at the lowermost part on one side, the second vertical square tube connecting parts  342  formed on the fourth vertical square tubes  340  in the center of one side, and the second vertical square tube connecting parts  335  formed on the third longitudinal square tube  330  at the uppermost part on one side. At this time, the second vertical square tube connecting part  322 , the three second vertical square tube connecting parts  342 , and the second vertical square tube connecting parts  335  are located on the same axis in the vertical direction, so that a second vertical square tube  420  formed in a straight shape can be integrally coupled with the respective connecting parts. 
     According to an embodiment of the present disclosure, one of the second vertical square tubes  420  on one side can be integrally coupled with the second vertical square tube connecting part  314  formed on the first vertical angle pipe  310  at the lower part on one side and the four second vertical square tube connecting parts  334  formed on the third longitudinal square tubes  330  at the upper part on one side. At this time, the second vertical square tube connecting part  314  and the four second vertical square tube connecting parts  334  are located on the same axis in the vertical direction, sot that the second vertical square tubes  420  formed in a straight shape may be integrally coupled with the respective connecting parts. 
     According to an embodiment of the present disclosure, one of the second vertical square tubes  420  on one side can be integrally coupled with the second vertical square tube connecting part  315  formed on the first vertical longitudinal square tube  310  at the lower part on one side and the four second vertical square tube connecting parts  335  formed on the third longitudinal square tubes  330  at the upper part on one side. At this time, the second vertical square tube connecting part  315  and the four second vertical square tube connecting parts  335  are located on the same axis in the vertical direction, so that the second vertical square tubes  420  formed in a straight shape may be integrally coupled with the respective connecting parts. 
     Hereinafter, the vertical square tube  400  according to an embodiment of the present disclosure will be described with reference mainly to  FIGS. 10 and 11 . 
     Referring to  FIG. 10 , the first vertical square tube  410  may include a longitudinal square tube connecting part  411  connected to a longitudinal square tube  300 . According to an embodiment of the present disclosure, the battery modules  210  are stacked in five stages, and the longitudinal square tube connecting part  411  is also formed in five stages at regular intervals, so that it can be coupled with each of the first or third longitudinal square tubes  310  and  330  disposed at the position corresponding to each position. 
     More specifically, the longitudinal square tube connecting part  411   a  formed at one end may be coupled with the first vertical square tube connecting parts  312  and  313  formed in the first longitudinal square tube  310  or the  1 - 1  vertical square tube connecting parts  317  and  318 . Further, the longitudinal square tube connecting part ( 411   b ) excluding the longitudinal square tube connection part  411   a  formed at one end can be coupled with the first vertical square tube connecting parts  332  and  333  formed on the third longitudinal square tube  330  or the  1 - 1  vertical square tube connecting parts  336  and  337 . 
     Referring to  FIG. 11 , the second vertical square tube  420  may include a longitudinal square tube connecting part  421  connected to a longitudinal square tube  300 , a horizontal square tube connecting part  422  connected to a horizontal square tube described later, and a bracket connecting part  423  for coupling with a bracket that connects the lower case and the battery module stack  200 , which will be described later. 
     According to an embodiment of the present disclosure concerning the longitudinal square tube connecting part  421 , the battery modules  210  are stacked in five stages. The longitudinal square tube connecting part  421  is also formed in five at regular intervals, and can be integrally coupled with the connecting parts formed in the second, fourth, or third longitudinal square tubes  320 ,  340 , and  330  arranged at the position corresponding to each position. 
     More specifically, the longitudinal square tube connecting part  421   a  formed at one end may be coupled to the second longitudinal square tube connecting parts  321  and  322  formed on the longitudinal square tube  320 . Further, the longitudinal square tube connecting part  421   b  formed at the other end may be coupled to the second vertical square tube connecting parts  334  and  335  formed on the third longitudinal square tube  330 . In addition, the longitudinal square tube connecting part  421   c  formed in the center may be coupled to the second vertical square tube connecting parts  341  and  342  formed in the fourth longitudinal square tube  340 . 
     Hereinafter, the structure and arrangement of the horizontal square tube according to an embodiment of the present disclosure will be described with reference mainly to  FIGS. 13 to 15 . 
       FIG. 13  is a view illustrating the configuration of  FIG. 12  and horizontal square tubes according to an embodiment of the present disclosure.  FIG. 14  is a top view (a), a perspective view (b), and a side view (c) of horizontal square tubes according to an embodiment of the present disclosure.  FIG. 15  is a view illustrating a state in which a plurality of horizontal square tubes are coupled to the battery module stack of  FIG. 12 . 
     Referring to  FIGS. 13 to 15 , the horizontal square tubes  500  according to an embodiment of the present disclosure are formed in the front and rear directions of the stacked battery modules, and mounted on the battery module stack  200 , and coupled with all the part of each of the vertical square tubes  400  located on a plurality of axes in the front and rear directions among the plurality of vertical square tubes  400 , in the outside of each of the plurality of vertical square tubes  400 . 
     The plurality of horizontal square tubes  500  may be coupled with a plurality of second vertical square tubes  420  located on the same axis in the front and rear directions. A plurality of vertical square tube connecting parts  501  are formed in the horizontal square tube  500 . The plurality of vertical square connecting parts  501  may be coupled to the horizontal square tube connecting parts  422  formed on the plurality of second vertical square tubes  400 . 
     According to an embodiment of the present disclosure, the horizontal square tube  500  may be disposed one by one at each of the left and right sides of the battery module. Each of the horizontal square tubes  500  may be integrally coupled with the connecting parts  422  located at the uppermost part of the horizontal square tube connecting parts  422  formed in each of the second vertical square tubes  420 . 
     Referring to  FIGS. 14 and 17 , the vertical square tube connecting part  501  may be formed two by two in the center and one by one at both ends. Therefore, the two vertical square tube connecting parts  501   a  disposed in the center are coupled with the two connecting parts  422  located at the uppermost part of the two second vertical square tubes  420  located in the center of the battery module stack  200 , and the two vertical square tube connecting parts  501   b  disposed at both ends may be coupled to the two connecting parts  422  located at the uppermost part of the second vertical square tubes  420  located at both ends of the battery module stack  200 . 
     As shown in  FIG. 15 , in the water-cooled battery module structure according to the present disclosure, the cooling water pipe  900  may be formed on one surface of the battery module stack  200  so as to supply cooling water to the heat sink  600 . The cooling water pipe  900  may be fixed to one surface of the battery module stack  200  through the tongs  610   a  formed on one side of the heat sink insulator  610 . 
     Hereinafter, the overall configurations and effects of each of the aforementioned square tubes will be described with reference to the figures according to the present disclosure. 
     The coupling between the above-described vertical square tube  300 , the vertical square tube  400 , and the horizontal square tube  500  is made through a connecting part formed in each of the tubes. According to an embodiment of the present disclosure, the coupling of the respective connecting parts may be achieved through bolt-nut fastening. At the time of mutual fastening, each tube needs hole drilling, nut welding, back cutting-out for access to welding tools, bracket welding attachment, etc. Thereby, the final shape type can be classified. 
     In the respective square tubes, the first to fourth longitudinal square tubes  310 ,  320 ,  330  and  340  are arranged in the left and right directions based on the battery module, the first and second vertical square tubes  410  and  420  are arranged vertically in the front-back and up-down directions based on the battery module, the horizontal square tubes  500  are arranged in the front and rear directions based on the battery module, so that a horizontal-vertical-height lattice structure is formed on the outer periphery of the battery modules  210  around the battery modules  210 , thereby constraining six degrees of freedom of the battery modules  210 . 
     The longitudinal square tube  300 , the vertical square tube  400  and the horizontal square tube  500  according to an embodiment of the present disclosure are mechanically fixed and pressure-resistant rigid structures of the battery modules  210 . As shown in the figures of the respective square tubes, steel square tube with a square cross section can be used. The square tube has dimensions of 20 to 40 mm in width and 20 to 40 mm in length, which may be a value considering the bolt-nut assembly surface used when assembling the vehicle parts of the battery pack. 
     The square tube may have a thickness of 1.0 mm to 3.0 mm. The cross-sections of the square tubes shown in  FIGS. 4 to 7, 10, 11, and 14  may be formed to have a width of 40 mm, a length of 25 mm, and a thickness of 2 mm. As described above, although there are some modifications of the connecting part, the cut-out part, the support part, etc. in the square tubes, the cross-sectional outer size of each of the seven types of square tubes is the same, and thus, the cross-section of respective square tubes is simplified as much as possible, so that price competitiveness of parts can be secured. 
     According to the present disclosure, in a single section, the fixed structure design of the battery module stack  200  is completed with only total seven types of square tubes of the first longitudinal square tube  310 , the second longitudinal square tube  320 , the third longitudinal square tube  330 , the fourth longitudinal square tube  340 , the first vertical square tube  410 , the second vertical square tube  420  and the horizontal square tub  500 , and brackets  130 , so that the components are simple and price competitiveness can be secured. 
     Further, as the square tubes are disposed more outside than the outside of the battery modules, the square tubes coupled to each other at the time of crimping the battery module stack  200  receives a load first, so that a force transmitted to the battery modules due to the high stiffness of the square tubes is lowered, thereby improving crimping stability. 
     In addition, compared to a structure in which modules stacked in multiple layers are fixed by bonding between press plate structures, the weight specific stiffness of the square tubes according to an embodiment of the present disclosure is excellent, and a relatively lightweight battery pack can be manufactured. 
     Hereinafter, a battery module stack in which BMS and BDU are combined according to an embodiment of the present disclosure will be described with reference to  FIGS. 16 to 20 . 
       FIG. 16  is a view illustrating a state in which BMS and BDU are coupled to a battery module stack according to an embodiment of the present disclosure.  FIG. 17  is a front view of  FIG. 16 .  FIG. 18  is a rear view of  FIG. 16 .  FIG. 19  is a top view of  FIG. 16 .  FIG. 20  is a cross-sectional view illustrating a portion A-A′ of  FIG. 19 . 
     Referring to  FIGS. 16 to 20 , a BMS  700  and a BDU  800  may be coupled to the top of the battery module stack  200  of the present disclosure. 
     The BMS  700  refers to a battery management system (BMS), and serves to manage the temperature or voltage of battery modules. The BDU  800  refers to a battery disconnect unit, and serves to control electrical connection of battery modules. 
     Referring to  FIG. 16 , the BMS  700  and the BDU  800  may be arranged side by side on the upper part of the battery module stack  200 . Referring to  FIG. 17 , the BMS  700  and the BDU  800  may be arranged between the third longitudinal square tubes  330  disposed at the uppermost part of the battery module stack  200 . 
     According to an embodiment of the present disclosure, the BMS  700  and the BDU  800  may be coupled with the third longitudinal square tubes  330  disposed at the uppermost part of the battery module stack  200 . More specifically, as shown in  FIG. 19 , the four connecting parts  701  formed on the side of the BMS  700 , and the four connecting parts  801  formed on the side surfaces of the BDU  800  are coupled with the connecting parts  331  formed in the third longitudinal square tubes  330 , respectively, so that the BMS  700  and the BDU  800  may be coupled to the battery module stack  200 . 
     According to an embodiment of the present disclosure, the connecting parts  701  of the BMS  700  and the connecting parts  331  of the third longitudinal square tube  330  may be coupled with a bolt  702 . The connecting part  801  of the BDU  800  and the connecting part  331  of the third longitudinal square tube  330  may be similarly coupled with a bolt  802 . However, the combination method is not limited thereto, and the BMS  700  and the BDU  800  may be fixed to the battery module stack  200  through various coupling methods. 
     Hereinafter, the case mounting structure of a bracket and a module stack including a battery according to an embodiment of the present disclosure will be described with reference to  FIGS. 21 to 23 . 
       FIG. 21  is a view illustrating a battery module stack, upper and lower cases, and brackets according to an embodiment of the present disclosure.  FIG. 22  is a view illustrating a lower case according to an embodiment of the present disclosure.  FIG. 23  is a view illustrating a state in which the upper and lower cases are assembled according to an embodiment of the present disclosure. 
     Referring to  FIGS. 21 to 23 , the battery module stack  200  according to an embodiment of the present disclosure may be mounted inside the upper case  110  and the lower case  120  to physically and chemically protect the battery modules  210  from the outside. 
     The battery module stack  200  may be coupled to the lower case  120  via the bracket  130  shown in  FIG. 21 . The bracket  130  includes first brackets  131  formed on the left side of the battery module and second brackets  132  formed on the right side of the battery module. According to an embodiment of the present disclosure, each of the first and second brackets  131  and  132  may be formed of four, and is disposed four by four on the left and right sides of the battery module stack  200 , so that the battery module stack  200  can be fixed to the lower case  120 . 
     One end of the bracket  130  may be coupled to the bracket connecting part  121  formed on the lower case  120 . According to an embodiment of the present disclosure, a first bracket connecting part  121   a  formed in four is formed on one side of the upper end of the lower case  120 , and the four first bracket connecting parts  121   a  may be respectively coupled to the four first brackets  131 . Further, a second bracket connecting part  121   b  formed in four is formed on the other side of the upper end of the lower case  120 , and the four second bracket connecting parts  121   b  may be coupled to the four second brackets  132 , respectively. 
     The other end of the bracket  130  may be coupled to the bracket connecting part  423  of the second vertical square tube  420 . According to an embodiment of the present disclosure, the four second vertical square tubes  420  are formed on the left side of the battery module stack  200 , and the bracket connecting parts  423  formed on each of the four second vertical square tubes  420  may be coupled to the other ends of the four first brackets  131 , respectively. Further, four second vertical square tubes  420  are formed on the right side of the battery module stack  200 , and bracket connecting parts  423  formed on each of the four second vertical square tubes  420  may be coupled to the other ends of the four second brackets  132 , respectively. 
     The longitudinal square tube connecting part  122  may be formed at the lower part of the lower case  120 . According to an embodiment of the present disclosure, the support parts  316  formed at both ends of the first longitudinal square tubes  310  disposed at both ends of the lowermost part of the battery module stack  200  can be coupled with the four longitudinal square tube connecting parts  122   a  disposed two by two at each end of the lower case  120 . Further, the support parts  324  formed at both ends of the second longitudinal square tubes  320  disposed in the center of the lowermost part of the battery module stack  200  can be coupled with the four longitudinal square tube connecting part  122   b  arranged two by two at each end of the lower case  120 . 
     The bracket connection part  423  may be formed in the middle of each second vertical square tube, and the bracket  130  coupled to the bracket connecting part  423  are located at an intermediate height of the battery module stack  200  to effectively suppress the flow of the battery module stack  200  having a high center of gravity. 
     Hereinafter, a method of manufacturing a battery pack according to an embodiment of the present disclosure will be described with reference to  FIGS. 8, 12, and 15 . 
       FIG. 8  is a view illustrating a state in which longitudinal square tubes are coupled to the battery module stack according to an embodiment of the present disclosure.  FIG. 12  is a view illustrating a state in which a plurality of vertical square tubes are coupled to the battery module stack of  FIG. 9 .  FIG. 15  is a view illustrating a state in which a plurality of horizontal square tubes are coupled to the battery module stack of  FIG. 12 . 
     A method for manufacturing a battery pack according to an embodiment of the present disclosure sequentially performs the steps of: stacking and arranging a plurality of longitudinal square tubes  300  mounted on the battery module stack  200  in a vertical direction between the stacked battery modules  210  so as to be coupled integrally with the battery modules  210  formed in the left and right directions at the uppermost part and the lowermost part; coupling a plurality of vertical square tubes  400  with all of the longitudinal square tubes  300  respectively located on a plurality of longitudinal axes of the stacked longitudinal square tubes  300  in the four-direction outer periphery of the battery module stack  120 ; and in the outside of the plurality of vertical square tubes, coupling a plurality of horizontal square tubes  500  with all of the parts of the vertical pipes  400  respectively located on a plurality of axes in the front and rear directions among the plurality of vertical square tubes  400 . 
     A state in which the plurality of longitudinal square tubes  300  are arranged can be confirmed in  FIG. 8 . As shown in  FIG. 8 , as the battery modules  210  are stacked upward, a plurality of vertical square tubes  300  may be stacked and disposed to correspond to each battery module  210 . 
     A state in which the plurality of vertical square tubes  400  are arranged can be confirmed through  FIG. 12 . As shown in  FIG. 12 , a plurality of longitudinal square tubes  400  may be arranged to be connected to a plurality of longitudinal square tubes  300  in the vertical direction to fix the plurality of vertical square tubes  400 . 
     A state in which the plurality of horizontal square tubes  500  are arranged can be confirmed through  FIG. 15 . As shown in  FIG. 15 , a plurality of horizontal square tubes  500  are arranged to be connected to a plurality of vertical square tubes  400  in the front and rear direction, a plurality of longitudinal square tubes  300  and a plurality of vertical square tubes  400  can be fixed. 
     According to an embodiment of the present disclosure, after the step of combining the plurality of horizontal square tubes  500 , the battery module stack  200  is attached to the lower case  120  through the bracket  130  as shown in FIG. The step of fixing and coupling the upper case  110  to the lower case  120  as shown in  FIG. 23  may be further included. 
     The battery pack can be applied to various devices. Such a device may be applied to a vehicle such as an electric bicycle, an electric vehicle, or a hybrid vehicle, but the present disclosure is not limited thereto, and is applicable to various devices that can use a battery module, which also belongs to the scope of the present disclosure. 
     Although the invention has been shown and described with reference to the preferred embodiments, the scope of the present disclosure is not limited thereto, and numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of the invention described in the appended claims. 
     Further, these modified embodiments should not be understood individually from the technical spirit or perspective of the present disclosure. 
     DESCRIPTION OF REFERENCE NUMERALS 
     
         
         
           
               110 : upper case 
               120 : lower case 
               121 : bracket connecting part 
               122 : longitudinal square tube connecting part 
               130 : bracket 
               131 : first bracket 
               132 : second bracket 
               210 : battery module 
               200 : battery module stack 
               300 : longitudinal square tube 
               310 : first longitudinal square tube 
               311 : connecting part 
               312 ,  313 : first vertical square tube connecting part 
               314 ,  315 : second vertical square tube connecting part 
               317 ,  318 :  1 - 1  vertical square tube connecting part 
               316 : support part 
               320 : second longitudinal square tube 
               321 ,  322 : second vertical square tube connecting part 
               323 : cut-out part 
               324 : support part 
               330 : third longitudinal square tube 
               331 : connecting part 
               332 ,  333 : first vertical square tube connecting part 
               334 ,  335 : second vertical square tube connecting part 
               336 ,  337 :  1 - 1  vertical square tube connecting part 
               340 : fourth longitudinal square tube 
               341 ,  342 : vertical square tube connecting part 
               343 : cut-out part 
               400 : vertical square tube 
               410 : first vertical square tube 
               411 : longitudinal square tube connecting part 
               420 : second vertical square tube 
               421 : longitudinal square tube connecting part 
               422 : horizontal square tube connecting part 
               423 : bracket connecting part 
               500 : horizontal square tube 
               501 : vertical square tube connecting part 
               600 : heat sink 
               610 : heat sink insulator 
               610   a : tongs part 
               611 : first heat sink insulator 
               612 ,  613 : second, third heat sink insulator 
               700 : BMS 
               701 : connecting part 
               800 : BDU 
               801 : connecting part 
               900 : cooling water pipe