Patent Publication Number: US-2021167342-A1

Title: Battery pack

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Korean Patent Application No. 10-2019-0157508, filed on Nov. 29, 2019, in the Korean Intellectual Property Office, and entitled: “Battery Pack,” is incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     One or more embodiments relate to battery packs. 
     2. Description of Related Art 
     Typically, secondary batteries, unlike primary batteries that are not chargeable, are chargeable and dischargeable batteries. The secondary batteries are used as energy sources of mobile devices, electric vehicles, hybrid vehicles, electric bicycles, uninterruptible power supplies, and the like, in the form of a single battery cell according to a type of an external device to apply, or in the form of a battery pack in which a plurality of battery cells are assembled in one unit. 
     While compact mobile devices, e.g., mobile phones, may be operated for a certain time with an output of a single battery, when long time driving or high power driving is necessary, e.g., in electric vehicles or hybrid vehicles consuming much power, battery packs may be used due to output and capacity, and the battery packs may increase an output voltage or an output current according to the number of built-in battery cells. 
     SUMMARY 
     According to one or more embodiments, a battery pack may include a plurality of battery cells disposed to form a cooling channel penetrating between battery cells neighboring to each other, each of the plurality of battery cells including a vent portion, a cell holder in which each of the plurality of battery cells is assembled, the cell holder including a hollow protruding portion surrounding the cooling channel and protruding in a direction opposite to the plurality of battery cells, and a separation member disposed on the cell holder, the separation member including an open area opened to allow the hollow protruding portion to be inserted therein and a shield area that closes above the vent portion. 
     For example, the shield area may be formed across the entire area of the separation member except the open area. 
     For example, the separation member may include a plate-shaped member in which the open area is punched in a hole shape. 
     For example, a discharge path of a discharge gas discharged from the vent portion may be formed between the shield area of the separation member and each of the plurality of battery cells or between the shield area and the cell holder. 
     For example, the shield area may form one end of the discharge path having one closed side above the vent portion, and a discharge hole may be formed at another end of the discharge path, the discharge hole being formed to penetrate the cell holder. 
     For example, the discharge path may be continuously formed from the vent portions of the plurality of battery cells to the discharge hole, and may be formed by a space between the hollow protruding portions continuously connected. 
     For example, the cooling channel may penetrate the separation member through the open area in a shape surrounded by the hollow protruding portion, to be spatially separated from the discharge path having one side closed by the separation member. 
     For example, the hollow protruding portion may include a wall body having a circular, overall, or polygonal shape surrounding the cooling channel. 
     For example, an outer circumference of the hollow protruding portion and an inner circumference of the open area may be assembled in an interference fit with respect to each other. 
     For example, the open area may include a wall body having an inner circumference of a size that is gradually reduced in a protrusion direction of the hollow protruding portion. 
     For example, a circuit board electrically connected to the plurality of battery cells may be provided between the cell holder and the separation member. 
     For example, an open area that is opened to allow the hollow protruding portion to be inserted therein may be formed in the circuit board. 
     For example, the open area of the circuit board may include a first open area formed separately in a hole shape for each cooling channel, and a second open area formed in a hole shape to be common to neighboring different cooling channels. 
     For example, the second open area may expose edge parts of a pair of battery cells neighboring to each other, with neighboring different cooling channels. 
     For example, a connection member may be provided between the edge parts of the battery cells exposed through the second open area and the circuit board. 
     For example, the first and second open areas may be disposed in an alternate pattern in a row direction of the plurality of battery cells. 
     For example, different pairs of cooling channels may be formed at both sides of one battery cell of the plurality of battery cells in the row direction of the plurality of battery cells, at least one cooling channel of a pair of cooling channels formed at one side of the one battery cell may be exposed through the first open area, and a pair of cooling channels formed at the other side of the one battery cell may be exposed through the second open area. 
     For example, the cell holder may include an upper holder in which an upper end portion of each of the plurality of battery cells is assembled and a lower holder in which a lower end portion of each of the plurality of battery cells is assembled, and the separation member may include an upper separation member disposed on the upper holder and a lower separation member disposed on the lower holder. 
     For example, a circuit board electrically connected to the plurality of battery cells may be provided between the upper holder and the separation member, and the cooling channel may be connected, from the upper separation member, to the lower separation member by penetrating the circuit board, the upper and lower holders, the plurality of battery cells assembled between the upper and lower holders. 
     For example, an upper duct and a lower duct, in which an inlet and an outlet of a cooling fluid flowing through the cooling channel are formed, may be respectively disposed in the upper separation member and the lower separation member. 
     For example, an opening may be formed in any one of the upper duct and the lower duct, and a connection portion to which a fluid device is connected may be formed in another duct. 
     For example, any one of the opening and the connection portion may form an inlet of a coolant flowing through the cooling channel, and another may form an outlet of the coolant flowing through the cooling channel. 
     For example, the opening and the connection portion may be formed at diagonal positions of the battery pack. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features will become apparent to those of skill in the art by describing in detail exemplary embodiments with reference to the attached drawings in which: 
         FIG. 1  is an exploded perspective view of a battery pack according to one or more embodiments; 
         FIG. 2  is a perspective view of a battery cell of  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of a structure of a cell holder in which a battery cell is assembled; 
         FIG. 4  illustrates the battery cell of  FIG. 2  to describe a cooling channel; 
         FIG. 5  illustrates the circuit board of  FIG. 1 ; 
         FIGS. 6 and 7  illustrate opposite surfaces of the separation member of  FIG. 1 ; 
         FIG. 8  illustrates a spatial separation of a coolant of a cooling channel from a discharge path by a separation member; and 
         FIG. 9  is an exploded perspective view of an upper duct and a lower duct. 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey exemplary implementations to those skilled in the art. 
     In the drawing figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. Like reference numerals refer to like elements throughout. 
     Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. 
     A battery pack according to one or more embodiments is described with reference to the accompanying drawings. 
       FIG. 1  is an exploded perspective view of a battery pack according to one or more embodiments.  FIG. 2  is a perspective view of a battery cell of  FIG. 1 .  FIG. 3  is an exploded perspective view of a structure of a cell holder in which a battery cell is assembled.  FIG. 4  illustrates the battery cell of  FIG. 2  to describe a cooling channel.  FIG. 5  illustrates the circuit board of  FIG. 1 .  FIGS. 6 and 7  illustrate opposite surfaces of the separation member of  FIG. 1 .  FIG. 8  illustrates a spatial separation of a coolant of a cooling channel from a discharge path by a separation member.  FIG. 9  is an exploded perspective view of an upper duct and a lower duct. 
     Referring to  FIGS. 1 and 2 , a battery pack according to one or more embodiments may include a plurality of battery cells  10 , each including a vent portion  13 , a cooling channel F formed to penetrate between the battery cells  10  neighboring to each other, and a separation member  140  including a shield area  144  corresponding to the vent portion  13  and an open area  145  extending across the battery cells  10  and opened such that the cooling channel F may penetrate the same. 
     Referring to  FIG. 2 , each of the battery cells  10  may be provided as a cylindrical battery cell which may include an upper end portion  10   a  and a lower end portion  10   b  in a length direction and an outer circumferential surface  10   c  having a cylindrical shape between the upper end portion  10   a  and the lower end portion  10   b . First and second electrodes  11  and  12  having polarities different from each other may be respectively formed at the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10 . For example, the first and second electrodes  11  and  12  of each of the battery cells  10  may correspond to a first polarity, e.g., a negative pole, and a second polarity, e.g., a positive pole, of each of the battery cells  10 . 
     In the present specification, the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10  may be classified according to the location thereof, rather than the first and second polarities, which respectively means an end portion formed at an upper position and an end portion formed at a lower position in the length direction of each of the battery cells  10 . In other words, according to the specific arrangement of the battery cells  10 , the upper end portions  10   a  of the battery cells  10  neighboring to each other may have the same first polarity or the same second polarity, or the first and second polarities different from each other. As described below, in an embodiment, the battery cells  10  neighboring to each other may be arranged in an alternately reversed pattern in a vertical direction, e.g., the battery cells  10  may alternate in an up or down direction. Accordingly, the upper end portions  10   a  of the battery cells  10  neighboring to each other may have the first and second polarities different from each other, the lower end portions  10   b  of the battery cells  10  neighboring to each other may have the first and second polarities different from each other. 
     One of the battery cells  10  may be electrically connected to another of the battery cells  10  that neighbors thereto, in which the battery cells  10  neighboring to each other may be arranged in the vertically alternately reversed pattern in the electrical connection direction. Accordingly, the first and second polarities different from each other of the battery cells  10  neighboring to each other may be connected in series. However, in another embodiment, the same first and second polarities of battery cells neighboring to each other may be connected in parallel. 
     In an embodiment, each of a group of the battery cells  10  forming the battery pack may be connected in series to another of the battery cells  10  that neighbors thereto. The battery pack according to an embodiment may not include a parallel connection between the battery cells  10  neighboring to each other. However, a battery pack according to another embodiment may include a serial connection and/or a parallel connection between battery cells neighboring to each other. 
     In an embodiment, the battery cells  10  neighboring to each other may be arranged in the vertically alternately reversed pattern in the electrical connection direction, and by connecting the upper end portions  10   a  of the battery cells  10  neighboring to each other or the lower end portions  10   b  of the battery cells  10  neighboring to each other, to each other, a serial connection between the first and second polarities different from each other may be formed. However, in another embodiment, a parallel connection between the same first and second polarities may be formed. 
     In the present specification, the electrical connection direction of the battery cells  10  may mean a direction in which the battery cells  10  neighboring to each other are electrically connected to each other, and may include all different directions in which the battery cells  10  are connected to each other through a plurality of busbars  120 , rather than any one specific direction. 
     The cooling channel F may be formed between the battery cells  10  neighboring to each other. A coolant flowing through the cooling channel F may contact and cool the, e.g., external surfaces of the, battery cells  10 . The cooling channel F may extend to the outside of the battery cells  10  in the length direction of the battery cells  10  by penetrating between the battery cells  10  neighboring to each other. The cooling channel F that is formed to penetrate almost the entire battery pack may be in fluid communication with the outside of the battery pack through an inlet or an outlet of the cooling channel F. In this state, the cooling channel F may extend across the battery pack to penetrate almost the entire battery pack in the length direction of the battery cells  10 . The cooling channel F is described in detail below. 
     Referring to  FIG. 2 , the vent portion  13  may be formed in at least any one of the upper end portion  10   a  or the lower end portion  10   b  of each of the battery cells  10 . When an end portion of each of the battery cells  10  where the vent portion  13  is formed, among the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10 , is referred to as one end portion of each of the battery cells  10 , the vent portion  13  may be formed along an edge of the one end portion of each of the battery cells  10 . For example, the vent portion  13  may be formed along an edge of the second electrode  12  that is formed at a center portion of one end portion of each of the battery cells  10 , and may be formed along an edge of the one end portion of each of the battery cells  10 . 
     For example, the vent portion  13  may include a plurality of vent portions  13  arranged apart from each other along, e.g., a perimeter of, the edge of one end portion of each of the battery cells  10 . The vent portion  13  may remove the internal pressure of the battery cells  10 . For example, the vent portion  13  may correspond to a portion of one end portion of the battery cells  10 , the portion being formed with relatively weak strength. When the internal pressure of the battery cells  10  increases over a preset critical pressure corresponding to a breaking pressure of the vent portion  13 , the vent portion  13  is broken, and thus the internal pressure may be removed. As described below, the discharge gas discharged through the vent portion  13  according to the internal pressure of the battery cells  10  may be discharged to the outside of the battery pack along a discharge path with one side closed by the shield area  144  of the separation member  140 . In other words, the shield area  144  corresponding to the vent portion  13  of each of the battery cells  10  may be formed in the separation member  140 , the discharge gas discharged through the vent portion  13  may be discharged to the outside of the battery pack through a discharge path formed between the shield area  144  of the separation member  140  and each of the battery cells  10 . The separation member  140  and the discharge path will be described in detail below. 
     Referring to  FIG. 3 , a cell holder  110  may be assembled to the battery cells  10 . The cell holder  110  may include an upper holder  110   a  into which the upper end portion  10   a  of each of the battery cells  10  is inserted and a lower holder  110   b  into which the lower end portion  10   b  of each of the battery cells  10  is inserted. Except the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10  respectively inserted into the upper holder  110   a  and the lower holder  110   b , a central position in the length direction of the battery cells  10  may be exposed between the upper holder  110   a  and the lower holder  110   b , e.g., the upper and lower holders  110   a    110   b  may be vertically spaced apart from each other to expose centers of the battery cells  10  along the vertical direction in an assembled state. In this state, the cooling channel F may be formed between the battery cells  10  neighboring to each other, and the central position of the battery cells  10  exposed between the upper holder  110   a  and the lower holder  110   b  may be directly exposed to the coolant flowing in the cooling channel F to be cooled. In an embodiment, the coolant may correspond to low-temperature air introduced from the outside of the battery pack. However, in another embodiment, the coolant may include a coolant in a gaseous state other than air, e.g., a refrigerant gas. 
     An assembly rib  111  into which the upper end portion  10   a  of each of the battery cells  10  and the lower end portion  10   b  of each of the battery cells  10  are inserted may be formed in each of the upper holder  110   a  and the lower holder  110   b . The assembly rib  111  may restrict an assembly position of each of the battery cells  10  by surrounding the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10 . The assembly rib  111  may protrude from a plate-shaped main body of the cell holder  110  in the length direction of the battery cells  10  in an inward direction toward the battery cells  10 , and may surround the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10  to support the battery cells  10 . 
     A terminal hole  112  for exposing the first and second electrodes  11  and  12  of the battery cells  10  may be formed in the cell holder  110 . The first and second electrodes  11  and  12  of the battery cells  10  exposed through the terminal hole  112  may be electrically connected to another of the battery cells  10  that neighbors thereto, via the busbars  120 . For example, the terminal hole  112  may be formed in an area in the cell holder  110 , the area being surrounded by the assembly rib  111  in which the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10  where the first and second electrodes  11  and  12  are formed are assembled. 
     As illustrated in  FIG. 2 , in an embodiment, the vent portion  13  may be formed in at least any one end portion of the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10 , and the vent portion  13  may be formed along the edge of one end portion surrounding the second electrode  12  formed at the one end portion of each of the battery cells  10 . In this state, the terminal hole  112  may be formed in a size or diameter enough to expose the vent portion  13  formed along the edge of the one end portion surrounding the second electrode  12  of each of the battery cells  10 , along with the second electrode  12  of each of the battery cells  10 . In an embodiment, the battery cells  10  neighboring to each other may be arranged in the vertically alternately reversed pattern. Accordingly, the vent portion  13  of each of the battery cells  10  may be formed in the upper end portion  10   a  of each of the battery cells  10  according to a detailed position of each of the battery cells  10  or in the lower end portion  10   b  of each of the battery cells  10 . In this state, the terminal hole  112  formed in each of the upper and lower holders  110   a  and  110   b  may be formed in a size or diameter enough to expose the vent portion  13  formed in each of the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10 , e.g., a diameter of the terminal hole  112  may be wider than a diameter defined by the vent portions  13  surrounding the second electrode  12  and may completely overlap and expose the vent portions  13 . 
     The discharge gas discharged through the vent portion  13  of each of the battery cells  10  may flow along the discharge path formed on the cell holder  110  through the terminal hole  112  of the cell holder  110 , and may be discharged to the outside of the battery pack through a discharge hole DH formed at one side of the cell holder  110 . In other words, the discharge hole DH may be formed at one side of the cell holder  110 , and the discharge hole DH may be in fluid communication with the vent portion  13  of each of the battery cells  10  so that the discharge gas discharged from the vent portion  13  may be gathered and discharged to the outside of the battery pack. In detail, the discharge hole DH may be formed at an edge of the cell holder  110 , particularly at one edge in a direction along a long side portion of the cell holder  110 . 
     A hollow protruding portion  115  for forming the cooling channel F may be formed in the cell holder  110 . The hollow protruding portion  115  may include a hollow portion at the center thereof, forming the cooling channel F, and a wall body  115   a  surrounding the hollow portion at the center. In an embodiment, the hollow protruding portion  115  may include the wall body  115   a  having a circular shape and surrounding the hollow portion at the center. However, the technical scope of the disclosure is not limited thereto, and the hollow protruding portion  115  may include the wall body  115   a  having, e.g., an oval shape or a polygonal shape (e.g., a hexagonal shape), surrounding the hollow portion at the center. 
     The hollow protruding portion  115  may protrude from the plate-shaped main body of the cell holder  110  outward in a direction opposite to the battery cells  10 . For example, the hollow protruding portion  115  may extend the cooling channel F formed between the battery cells  10  neighboring to each other to the outside of the battery cells  10  in the length direction of the battery cells  10 , and may form the cooling channel F having a shape surrounded by the wall body  115   a.    
     Referring to  FIG. 1 , the hollow protruding portion  115  may sequentially penetrate, in the length direction of the battery cells  10 , a circuit board  130  and the separation member  140  arranged above the cell holder  110 . In this state, the hollow protruding portion  115  may form the cooling channel F extending across the battery pack to penetrate almost the entire battery pack in the length direction of the battery cells  10 . In detail, the hollow protruding portion  115  of the upper holder  110   a  may sequentially penetrate the circuit board  130  and an upper separation member  140   a  arranged above the upper holder  110   a  in the length direction of the battery cells  10 , e.g., along a longitudinal direction of the battery cells  10  oriented from the lower end portion  10   b  toward the upper end portion  10   a , and the hollow protruding portion  115  of the lower holder  110   b  may penetrate a lower separation member  140   b  arranged above the lower holder  110   b  in the length direction of the battery cells  10 . Open areas  135  and  145  that are opened to insert the hollow protruding portion  115  therein may be formed in the circuit board  130  and the separation member  140 , respectively. The open areas  135  and  145  of the circuit board  130  and the separation member  140  may be shaped such that a position corresponding to the hollow protruding portion  115  is opened in the circuit board  130  and the separation member  140 . The open areas  135  and  145  of the circuit board  130  and the separation member  140  are described in detail below. 
     The position where the hollow protruding portion  115  is formed along the cell holder  110 , or the position of the cooling channel F formed by the hollow protruding portion  115 , is described with reference to  FIG. 4 . In an embodiment, at least a part of the cooling channel F, i.e., a portion where the cooling channel F between the battery cells  10  neighboring to each other extends to the outside of the battery cells  10  in the length direction of the battery cells  10 , may be formed by the hollow protruding portion  115 , and the cooling channel F and the hollow protruding portion  115  may be formed at positions corresponding to each other, e.g., overlapping each other along a longitudinal direction of the battery cells  10 . In other words, the position of the cooling channel F may mean the position of the hollow protruding portion  115 . 
     The cooling channel F may be formed between the battery cells  10  neighboring to each other. In detail, the battery cells  10  may be provided as cylindrical battery cells, and as the battery cells  10  are arranged at alternate positions to be inserted between the battery cells  10  neighboring to each other, the battery cells  10  may be densely arranged, and as the battery cells  10  are densely arranged by using a space between the battery cells  10  neighboring to each other, a battery pack which may reduce ineffective dead space and have relatively high energy density compared to the same area may be provided. For example, the battery cells  10  may be arranged in a row direction of the battery cells  10 , and the battery cells  10  in the neighboring rows may be arranged at alternate, e.g., horizontally offset, positions so that the battery cells  10  in the neighboring rows may be inserted with respect to each other, e.g., in a honeycomb or zigzag arrangement. The row direction of the battery cells  10  may mean a direction in which the battery cells  10  are arranged when the battery cells  10  are linearly arranged in one direction. The row direction of the battery cells  10  may be different from a direction in which the battery cells  10  are electrically connected to each other, i.e., the electrical connection direction of the battery cells  10 , and the row direction of the battery cells  10  may mean a direction in which the battery cells  10  are arranged, without considering an electrical connection state of the battery cells  10 . 
     For example, referring to  FIG. 4 , the battery cells  10  of the first and second rows R 1  and R 2  may be densely arranged close to each other so that the battery cells  10  of the first row R 1  may be inserted between the battery cells  10  of the second row R 2 , e.g., the first row R 1  may be horizontally offset relative to the second row R 2  in a top view. Similarly, the battery cells  10  of the second and third rows R 2  and R 3  may be densely arranged close to each other so that the battery cells  10  of the second row R 2  may be inserted between the battery cells  10  of the third row R 3 . 
     As any one of the battery cells  10  is inserted between the battery cells  10  neighboring to each other, three battery cells  10 , e.g., in two rows, are arranged circumferentially adjacent to one another, e.g., two battery cells  10  from the second row R 2  and one battery cell  10  from the first row R 1  may form a triangle in a top view. In this state, the cooling channel F may be formed between the three battery cells  10  that are circumferentially adjacent to one another, e.g., the cooling channel F may be formed in the center of the resultant tringle of the three battery cells  10 . The cooling channel F may be formed in an extra area that is not occupied by the battery cells  10  between the three battery cells  10  that are circumferentially adjacent to one another, i.e., a valley area. 
     In detail, the cooling channel F may be formed between the battery cells  10  of the first row R 1  and the battery cells  10  of the second row R 2 , which neighbor each other. For example, one cooling channel F may be formed between two battery cells  10  of the first row R 1  and one battery cell  10  of the second row R 2 , and one cooling channel F may be formed between two battery cells  10  of the second row R 2  and one battery cell  10  of the first row R 1 . Similarly, the cooling channel F may be formed between the battery cells  10  of the second row R 2  and the battery cells  10  of the third row R 3 , which neighbor each other. For example, one cooling channel F may be formed between two battery cells  10  of the second row R 2  and one battery cell  10  of the third row R 3 , and one cooling channel F may be formed between two battery cells  10  of the third row R 3  and one battery cell  10  of the second row R 2 . 
     Referring to  FIG. 4 , six cooling channels F may be formed in the outer circumferential direction of one battery cell  10  belonging to the second row R 2 , e.g., six cooling channels F may be formed around a perimeter of one battery cell  10  as viewed in a top view. For example, one battery cell  10  belonging to the second row R 2  may form a plurality of valley areas in the outer circumferential direction with six battery cells  10 , i.e., the battery cells  10  of the first to third rows R 1 , R 2 , and R 3 , particularly forming a valley area with two battery cells  10  sequentially in the outer circumferential direction, thereby forming a total of six valley areas. As one cooling channel F is formed for each valley area, a total of six cooling channels F may be formed. 
     Referring to  FIG. 3 , the cell holder  110  may be provided with first and second output terminals  121  and  122  and a fuse terminal  123  connected to a fuse box. For example, the upper holder  110   a  may be provided with the first and second output terminals  121  and  122  having polarities different from each other, and the fuse terminal  123  interposed between the first and second output terminals  121  and  122  and for connection to the fuse box that forms a charge/discharge path. The first and second output terminals  121  and  122  may provide an electrical connection between an external device and a group of the battery cells  10  electrically connected to each other. Thus, a group of the battery cells  10  may supply discharge power to an external load through the first and second output terminals  121  and  122  or receive a supply of charge power from an external charger through the first and second output terminals  121  and  122 . The first and second output terminals  121  and  122  may be respectively connected to a high potential battery cell  10  having the highest electric potential and a low potential battery cell  10  having the lowest electric potential, among a group of the battery cells  10  electrically connected to each other through the busbars  120 . 
     The fuse box may form a charge/discharge path between the first and second output terminals  121  and  122 , and a charge/discharge path of a group of the battery cells  10  may penetrate the fuse box through the fuse terminal  123  connected to the fuse box. A fuse for blocking an overcurrent may be provided in the fuse box and may block the charge/discharge path in response to the overcurrent. 
     Referring to  FIGS. 1 and 2 , the busbars  120  may be disposed on the cell holder  110 . For example, upper and lower busbars  120   a  and  120   b  may be disposed on the upper holder  110   a  and the lower holder  110   b . The busbars  120  may be alternately disposed at alternate positions on the upper holder  110   a  and the lower holder  110   b  and may connect the battery cells  10  neighboring to each other in the electrical connection direction. In this state, each of the busbars  120  may electrically connect a pair of the battery cells  10  in the electrical connection direction. Thus, as a plurality of the busbars  120  are arranged in the electrical connection direction of the battery cells  10 , an electrical connection of a group of the battery cells  10  may be made. 
     Referring to  FIGS. 1 and 5 , the circuit board  130  may be disposed on the busbars  120 . The open area  135  (i.e., an opening) opened in a hole shape, which the cooling channel F penetrates, may be formed in the circuit board  130 . The cooling channel F may extend across, e.g., through, the circuit board  130  by penetrating the open area  135  of the circuit board  130 . For example, as the hollow protruding portion  115  of the cell holder  110  is inserted into the open area  135  of the circuit board  130 , the cooling channel F that penetrates the open area  135  of the circuit board  130  may be formed. To this end, the open area  135  of the circuit board  130  may be formed at a position corresponding to the hollow protruding portion  115  of the cell holder  110 , in a shape corresponding to the hollow protruding portion  115  of the cell holder  110 . In an embodiment, the open area  135  of the circuit board  130  may be formed in a circular shape corresponding to the hollow protruding portion  115  including the wall body  115   a  having a circular shape surrounding the hollow portion at the center thereof. However, the technical scope of the disclosure is not limited thereto, and the open area  135  of the circuit board  130  may have various shapes corresponding to the hollow protruding portion  115 , e.g., various oval and polygonal shapes (e.g., a hexagonal shape). For example, the outer circumference of the hollow protruding portion  115  may be inserted into the inner circumference of the open area  135 , and may contact at least a part of the inner circumference of the open area  135  along the inner circumference of the open area  135 . 
     The open area  135  of the circuit board  130  may include a first open area  131  separately formed for each the cooling channel F and a second open area  132  commonly formed with respect to a pair of the cooling channels F neighboring to each other. In the present specification, in connection with the second open area  132 , a pair of the cooling channels F neighboring to each other mean a pair of the cooling channels F facing each other with a connection member  125  (described below) therebetween. A detailed technical matter regarding the connection member  125  (i.e., a connector) is described below. 
     The first open area  131  is separately formed for each cooling channel F in a hole shape separately formed for each cooling channel F, to expose each cooling channel F from the circuit board  130 . Unlike the first open area  131 , the second open area  132  is provided in a hole shape that is commonly formed with respect to a pair of the cooling channels F neighboring to each other, to include a pair of the cooling channels F neighboring to each other or a pair of the cooling channels F facing each other with the connection member  125  therebetween, and may expose a pair of the cooling channels F neighboring to each other from the circuit board  130 . Furthermore, the second open area  132  may expose a part of the upper end portion  10   a  of each of the battery cells  10  with a pair of the cooling channels F neighboring to each other or a pair of the cooling channels F facing each other with the connection member  125  therebetween. In this state, the upper end portion  10   a  of each of the battery cells  10  in the connection member  125  may be connected to the upper end portion  10   a  of each of the battery cells  10  that is exposed through the second open area  132 . In other words, the first open area  131  may expose each separate cooling channel F, and the second open area  132  may expose a part of the upper end portion  10   a  of each of the battery cells  10  with a pair of the cooling channels F neighboring to each other. As the second open area  132  exposes a part of the upper end portion  10   a  of each of the battery cells  10 , one end portion of the connection member  125  may be connected to the upper end portion  10   a  of each of the battery cells  10  that is exposed from the circuit board  130  through the second open area  132 . As the other end portion of the connection member  125  is connected to the circuit board  130 , a voltage measurement line may be formed between the battery cells  10  and the circuit board  130 , and the second open area  132  may provide a connection hole CH to allow a connection of the connection member  125  across the circuit board  130 . A technical matter regarding the connection hole CH is described below in detail. 
     Referring to  FIG. 1 , the circuit board  130  may be disposed on the upper holder  110   a , but may not be disposed on the lower holder  110   b . In other words, the circuit board  130  may be selectively disposed on, e.g. only, one holder of the upper holder  110   a  and the lower holder  110   b . In an embodiment, the circuit board  130  may be disposed on the upper holder  110   a , and may gather voltage information about the battery cells  10  through the upper end portion  10   a  of each of the battery cells  10 . In other words, the circuit board  130  may gather the voltage information about the battery cells  10  through, e.g. only, one end portion of the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10 . For example, the circuit board  130  may gather the voltage information about the battery cells  10  through the upper end portion  10   a  of each of the battery cells  10 . 
     The battery cells  10  may include the first and second electrodes  11  and  12  different from each other formed on the upper end portion  10   a  and the lower end portion  10   b . According to an embodiment, however, in order to gather the voltage information about the battery cells  10 , the circuit board  130  does not need to be connected to both of the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10 , and the voltage information about the battery cells  10  may be identified through, e.g., only, one end portion of the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10 , e.g., the upper end portion  10   a  of each of the battery cells  10 . As the voltage information about the battery cells  10  may be all gathered through the circuit board  130  selectively disposed on the upper end portion  10   a  of each of the battery cells  10 , thereby the overall structure of the battery pack may be simplified. In an embodiment, the electrical connection of the battery cells  10  may be made from both sides of the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10 , and the voltage measurement of the battery cells  10  may be made from the upper end portion  10   a  of each of the battery cells  10  selectively among the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10 . 
     In contrast, if the voltage measurement were to be made from both sides of the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10  (unlike the present embodiment), a circuit board would have to be disposed at both sides of the upper end portion  10   a  and the lower end portion  10   b  of each of the battery cells  10 . Accordingly, the overall structure of a battery pack with multiple circuit boards would have been complicated, and a separate wiring structure to connect the circuit boards at both sides would have been necessary to gather voltage information measured from the circuit boards at both sides. 
     Referring to  FIG. 5 , in an embodiment, the second open area  132  may function as the connection hole CH by exposing a pair of the cooling channels F neighboring to each other or a pair of the cooling channels F facing each other with the connection member  125  therebetween, with a part of the upper end portion  10   a  of each of the battery cells  10 . Accordingly, in an embodiment, the second open area  132  and the connection hole CH may indicate substantially the same configuration, e.g., the same hole formed in the circuit board  130 . However, in the present specification, for convenience of understanding, separate reference numbers are given to the second open area  132  and the connection hole CH. 
     A part of the upper end portion  10   a  of each of the battery cells  10  may be exposed through the connection hole CH or the second open area  132 , and the connection member  125  may be connected to the upper end portion  10   a  of each of the battery cells  10  exposed from the circuit board  130 . For example, the connection member  125  may be provided as a conductive wire or conductive ribbon including one end portion connected to the upper end portion  10   a  of each of the battery cells  10  and the other end portion connected to the circuit board  130 . The connection member  125  may be formed through wire bonding for bonding one end portion and the other end portion of a conductive wire respectively to the upper end portion  10   a  of each of the battery cells  10  and the circuit board  130 , or ribbon bonding for bonding one end portion and the other end portion of a conductive ribbon respectively to the upper end portion  10   a  of each of the battery cells  10  and the circuit board  130 . In an embodiment, the conductive wire as the connection member  125  may include a pair of conductive wires connecting the battery cells  10  and the circuit board  130 . In case of disconnection of the conductive wire due to lack of mechanical strength, each of the battery cells  10  and the circuit board  130  may be firmly connected by the pair of conductive wires. As the conductive ribbon has a higher mechanical strength than the conductive wire, the conductive ribbon does not need to be provided in a pair in case of disconnection, and thus the battery cells  10  and the circuit board  130  may be electrically connected through a single conductive ribbon. For reference, the connection member  125  illustrated in  FIG. 5  as an example may correspond to a conductive ribbon. 
     The connection hole CH may be formed in an area of the circuit board  130  overlapping a pair of the battery cells  10  neighboring to each other, to expose together a pair of the upper end portions  10   a  of the battery cells  10  neighboring to each other in the row direction of the battery cells  10 . For example, the connection hole CH may be formed in an area of the circuit board  130  overlapping a part of a pair of the battery cells  10  neighboring to each other in the row direction of the battery cells  10 , in detail, in an area overlapping edge parts of a pair of the battery cells  10 . The connection members  125  different from each other may be connected to the edge parts of the battery cells  10  neighboring to each other exposed through the connection hole CH. 
     The connection hole CH may be formed in an alternate pattern in the row directions, e.g., L 1  and L 2 , of the battery cells  10  or filling holes FH, to expose a pair of the battery cells  10  neighboring to each other in the row directions L 1  and L 2  of the battery cells  10  or the filling holes FH. In an embodiment, the first and second open areas  131  and  132  for exposing the cooling channel F may be formed in the circuit board  130 . The second open area  132  that functions as the connection hole CH and the first open area  131  that does not function as the connection hole CH may be arranged in the alternate pattern in the row directions L 1  and L 2  of the battery cells  10  or the filling holes FH. For example, the second open area  132  that functions as the connection hole CH may be formed one by one between a pair of the battery cells  10  or the filling holes FH in the row directions L 1  and L 2  of the battery cells  10  or the filling holes FH, and the connection hole CH may not be formed between another pair of the battery cells  10  or the filling holes FH. In other words, the second open area  132  may not be formed between the battery cells  10  or the filling holes FH, neighboring to each other, in the row directions L 1  and L 2  of the battery cells  10  or the filling holes FH, but may be formed at alternate positions between the battery cells  10  or the filling holes FH, neighboring to each other, in the row directions L 1  and L 2  of the battery cells  10  or the filling holes FH. In this state, among the battery cells  10  or the filling holes FH, neighboring to each other, the first open area  131  for exposing the cooling channel F penetrating between the battery cells  10  neighboring to each other may be formed at a position P where the second open area  132  is not formed, or a position adjacent thereto. 
     As described below, as the filling holes FH may be formed at central positions in the upper end portions  10   a  of the battery cells  10 , as described above, the arrangement of the first and second open areas  131  and  132  between the battery cells  10  neighboring to each other in the row direction of the battery cells  10  in the alternate pattern may include the arrangement of the first and second open areas  131  and  132  in the alternate pattern at a position adjacent to the position between the filling holes FH neighboring to each other, including the arrangement of the first and second open areas  131  and  132  between the filling holes FH neighboring to each other in the row directions L 1  and L 2  of the filling holes FH in the alternate pattern. For example, in an embodiment, the first open area  131  may be formed at a position adjacent to the position between the filling holes FH neighboring to each other in the row directions L 1  and L 2  of the filling holes FH, rather than the position between the filling holes FH neighboring to each other. Even in this state, the first open area  131  may be disposed between the battery cells  10  neighboring to each other. This is because the filling holes FH are formed at the central positions of the battery cells  10  neighboring to each other. 
     As described with reference to  FIG. 4 , six cooling channels F may be formed along the outer circumferential direction of one battery cell  10 . In this state, four cooling channels F may be formed at opposite sides of any one of the battery cells  10  in the row direction of the battery cells  10 . Among the four cooling channels F, at least one of two cooling channels F neighboring to each other formed at one side of the battery cells  10  may be exposed by the first open area  131  separately formed for each cooling channel F, two cooling channels F neighboring to each other formed at the other side of the battery cells  10  may be exposed by the second open area  132  that is commonly formed with respect to the two cooling channels F. As such, with respect to any one of the battery cells  10 , the first open area  131  may be formed at one side position, and the second open area  132  may be formed at the other side position. The first and second open areas  131  and  132  may be arranged in the alternate pattern in the row directions L 1  and L 2  of the battery cells  10  or the filling holes FH. In other words, the second open area  132  that functions as the connection hole CH and the first open area  131  that does not function as the connection hole CH may be arranged in the alternate pattern in the row directions L 1  and L 2  of the battery cells  10  or the filling holes FH. 
     The second open area  132  or connection hole CH may be formed in an area enough to include a pair of the cooling channels F neighboring to each other or a pair of the cooling channels F facing each other with the connection member  125  therebetween, with the edge parts of a pair of the battery cells  10  neighboring to each other. For example, a direction in which a pair of the battery cells  10  exposed through the second open area  132  face each other and a direction in which a pair of the cooling channels F or a pair of the cooling channels F facing each other with the connection member  125  therebetween, which is exposed through the second open area  132 , face each other may cross each other or cross each other perpendicularly. 
     In contrast, if one connection hole were to be formed for exposing the edge parts of a pair of the battery cells  10  neighboring to each other and two additional holes were to be formed for exposing each of the cooling channels F neighboring to each other, i.e., a total of three separate holes with a narrow gap therebetween (unlike the present embodiment), a breakage of the circuit board  130 , e.g., due to the narrow gaps between the holes, could have been caused. Therefore, according to an embodiment, the edge parts of a pair of the battery cells  10  neighboring to each other and a pair of the cooling channels F neighboring thereto, or a pair of cooling channels F facing each other with the connection member  125  therebetween, are all exposed through a single connection hole CH (or the second open area  132 ), thereby simplifying the structure of the circuit board  130  and preventing a possible breakage due to an insufficient strength of the circuit board  130   
     The connection member  125  for electrically connecting the upper end portion  10   a  of each of the battery cells  10  and the circuit board  130  exposed through the second open area  132  or the connection hole CH may be provided therebetween. The connection member  125  may transmit the voltage information about the battery cells  10  to the circuit board  130 . In detail, the connection member  125  may electrically connect the upper end portion  10   a  of each of the battery cells  10  to a connection pad  133  of the circuit board  130 . The connection pad  133  of the circuit board  130  may be formed around the connection hole CH, e.g., a pair of the connection pad  133  respectively electrically connected to a pair of the battery cells  10  neighboring to each other may be formed at positions facing each other around the connection hole CH. 
     As described below, the filling holes FH for exposing a coupling portion between the busbars  120  and the upper end portion  10   a  of each of the battery cells  10  may be formed in the circuit board  130 . The filling holes FH may be formed at the central position of the upper end portion  10   a  of each of the battery cells  10  to expose the busbars  120  coupled to the central position of the upper end portion  10   a  of each of the battery cells  10 . In an embodiment, the second open area  132  may include an extension portion  132   a  extending in the outer circumferential direction to surround the filling holes FH. The second open area  132  or the connection hole CH may expose, in addition to a pair of the cooling channels F neighboring to each other or a pair of the cooling channels F facing each other with the connection member  125  therebetween, another cooling channel F neighboring to the pair of the cooling channels F neighboring each other in the outer circumferential direction of the filling hole FH. For example, the second open area  132  may expose three cooling channels F together. In this state, the three cooling channels F exposed through the second open area  132  may correspond to three cooling channels F continuously arranged in the outer circumferential direction surrounding the filling holes FH. For example, as described in  FIG. 4 , six cooling channel F may be formed along the outer circumferential direction of one battery cell  10 , and among the six cooling channel F, three cooling channels F neighboring to each other may be exposed together through the second open area  132 . 
     Referring to  FIG. 5 , the second open area  132  extending in the outer circumferential direction of the filling hole FH of rows, for example, the rows L 1  and L 2 , neighboring to each other may be formed in shapes different from each other. For example, in the second open area  132  of the first row L 1  extending in the outer circumferential direction of the filling hole FH, the extension portion  132   a  may extend in a downward direction from the connection member  125  in the outer circumferential direction of the filling hole FH toward the filling holes FH of a second row L 2 . Unlike the above, in the second open area  132  of the second row L 2  extending in the outer circumferential direction of the filling hole FH, the extension portion  132   a  may extend in an upward direction from the connection member  125  in the outer circumferential direction of the filling hole FH toward the filling holes FH of the first row L 1 . As such, in the filling holes FH of the first and second rows L 1  and L 2  neighboring to each other, by forming the extension directions of the extension portion  132   a  extending in the outer circumferential direction of the filling hole FH to be different from each other, while avoiding interference therebetween, the extension portion  132   a  having different extension directions may be densely arranged in a narrow space between the filling holes FH of the first and second rows L 1  and L 2 . Although the second open area  132  is described above as extending in the outer circumferential direction of the filling hole FH, in another embodiment, the filling holes FH may be omitted. In this state, the second open area  132  may be understood to be extending in the outer circumferential direction of the central position of the upper end portion  10   a  of the battery cells  10 . The filling holes FH may be formed at the central position of the upper end portion  10   a  of each of the battery cells  10  to expose the busbars  120  coupled to each other. 
     At least one connection recess CR may be formed in an edge area of the circuit board  130 . The connection hole CH having a shape closed from the outside may be formed in the inside area of the circuit board  130  to expose the upper end portion  10   a  of each of the battery cells  10 , and the connection member  125  is connected to the circuit board  130  through the exposed upper end portion  10   a  of each of the battery cells  10  so that a voltage measurement may be made. Unlike the above, the connection recess CR having a shape opened to the outside may be formed in the edge area of the circuit board  130  to expose the upper end portion  10   a  of some of the battery cells  10 , and the connection member  125  is connected to the circuit board  130  through the exposed upper end portion  10   a  of some of the battery cells  10  so that a voltage measurement may be made. For example, the connection recess CR may have a concave shape as the edge area of the circuit board  130  is recessed inwardly. In an embodiment, the connection recess CR may be formed at least one position along a first side S 1  of the circuit board  130  neighboring to the first and second output terminals  121  and  122  and the fuse terminal  123 . For example, the connection recess CR may be formed along a long side portion side of the circuit board  130  neighboring to the first and second output terminals  121  and  122  and the fuse terminal  123 . For example, to avoid physical interference with the first and second output terminals  121  and  122 , the fuse terminal  123 , and the like, the connection recess CR concavely recessed in a direction away from the first and second output terminals  121  and  122  and the fuse terminal  123  may be formed in the first side S 1  of the circuit board  130 . 
     The connection recess CR may expose the upper end portion  10   a  of each of the battery cells  10  and simultaneously the cooling channel F. For example, the connection recess CR may be formed as a shape extending from an opening to expose the upper end portion  10   a  of each of the battery cells  10  to an opening to expose the cooling channel F. The connection recess CR may expose one cooling channel F of a pair of the cooling channels F neighboring to each other, and the other cooling channels F may be formed at positions outside the connection recess CR. 
     The connection hole CH having a shape closed from the outside may be formed in the inside area of the circuit board  130 . As the connection recess CR having a shape opened to the outside and inwardly recessed is formed in the edge area of the circuit board  130 , a contact position for the connection member  125  may be obtained. In an embodiment, according to a relative position of the circuit board  130  disposed on the upper holder  110   a  or the battery cell  10  fixed to the upper holder  110   a , a part of the upper end portion  10   a  of each of the battery cells  10  may be exposed through a second side S 2  that is flat of the circuit board  130 , out of the circuit board  130 . The connection member  125  may be connected to the upper end portion  10   a  of each of the battery cells  10  exposed through the second side S 2  of the circuit board  130 . In other words, according to a relative position of the circuit board  130  with respect to the upper holder  110   a  or the battery cell  10  fixed to the upper holder  110   a , a part of the upper end portion  10   a  of each of the battery cells  10  may be exposed out of the circuit board  130 . In this state, like the connection recess CR or the connection hole CH, a separate structure to expose the upper end portion  10   a  of each of the battery cells  10  may not be needed. For example, the second side S 2  may corresponding to a side opposite to the first side S 1  of the circuit board  130  adjacent to the first and second output terminals  121  and  122  and the fuse terminal  123 . The first and second sides S 1  and S 2  may correspond to the long side portion sides of the circuit board  130  that are opposite to each other. 
     The filling holes FH that exposes the coupling portion between the busbars  120  and the upper end portion  10   a  of each of the battery cells  10  may be formed in the circuit board  130 . The upper end portion  10   a  of each of the battery cells  10  may form a first electrode  11  or the second electrode  12  of the battery cells  10 , and may be connected by the busbars  120  to be electrically connected to another of the battery cells  10  that neighbors thereto. The filling holes FH may be formed in an area corresponding to the terminal hole  112  of the cell holder  110 , and may expose the coupling portion between the upper end portion  10   a  of each of the battery cells  10  and the busbars  120 , which is exposed through the terminal hole  112  of the cell holder  110 . The filling holes FH may be filled with potting resin for insulating and protecting the coupling portion between the busbars  120  and the upper end portion  10   a  of each of the battery cells  10  from the outside. The filling holes FH may provide a filling position of the potting resin to hermetically protect the coupling portion by covering the coupling portion between the busbars  120  and the upper end portion  10   a  of each of the battery cells  10  by penetrating the circuit board  130 . In an embodiment, the coupling portion between the busbars  120  and the upper end portion  10   a  of each of the battery cells  10  may include a welding portion, and to block harmful components such as air or moisture and prevent time-dependent degradation of the welding portion such as Galvanic corrosion, the coupling portion between the busbars  120  and the upper end portion  10   a  of each of the battery cells  10  may be covered using the potting resin. The potting resin may be formed on a coupling portion between the busbars  120  and the lower end portion  10   b  of each of the battery cells  10 . As the potting resin covers the coupling portion between the busbars  120  and the lower end portion  10   b  of each of the battery cells  10 , the coupling portion such as the welding portion may be protected from harmful components and may be insulated from the external environment. 
     Referring to  FIG. 6 , a thermistor  128  for measuring temperature may be disposed on the circuit board  130 . For example, the thermistor  128  may be provided as a chip-type thermistor to be directly mounted on the circuit board  130  through solder mounting. In an embodiment, the thermistor  128  may be mounted on the circuit board  130 , and may be disposed at an edge position of the circuit board  130 . For example, the thermistor  128  may be disposed at one edge position in a direction along the long side portion of the circuit board  130 . A fluid device (e.g., a connection portion M of the fluid device) for forcibly flowing a coolant may be disposed at the other edge position in the direction along the long side portion of the circuit board  130 . The long side portion direction of the circuit board  130  may correspond to a direction parallel to the long side portion direction of the battery pack. In an embodiment, as the thermistor  128  is disposed at a position opposite to the fluid device in the long side portion direction of the circuit board  130 , according to a heat dissipation structure, temperature information may be obtained from a position having a high possibility of high temperature degradation, that is, a position opposite to the fluid device, local degradation of the battery pack may be sensitively captured, and safety accident such as fire or explosion of the battery cells  10  may be prevented in advance. 
     Referring to  FIGS. 6 to 8 , the separation member  140  may be disposed on the cell holder  110 . The separation member  140  may spatially separate the cooling channel F of a coolant CM for cooling the battery cells  10  from the discharge path of a discharge gas DG discharged from the vent portion  13  of each of the battery cells  10 . In other words, as the separation member  140  spatially separates the cooling channel F from the discharge path, risk of explosion or fire according to a mixture of the discharge gas DG of high temperature and high pressure flowing through the discharge path and the coolant CM such as air flowing through the cooling channel F may be removed. Furthermore, in a battery pack mounted on an electric vehicle, the discharge gas DG may be prevented from being introduced into the interior of the vehicle through an uncontrolled path. 
     Referring to  FIG. 1 , the separation member  140  may include the upper separation member  140   a  disposed on the upper holder  110   a  and the lower separation member  140   b  disposed below the lower holder  110   b . For example, the upper separation member  140   a  may be disposed on the circuit board  130  that is disposed on the upper holder  110   a . In an embodiment, as the circuit board  130  may not be disposed on the lower holder  110   b , the lower separation member  140   b  may be directly disposed below the lower holder  110   b . For example, the lower separation member  140   b  may be disposed on a lower busbar  120   b  disposed on the lower holder  110   b.    
     Referring to  FIG. 6 , the open area  145  that is opened to allow the cooling channel F to penetrate the same may be formed in the separation member  140 . The cooling channel F may be formed across the separation member  140  by penetrating the open area  145  of the separation member  140 . For example, as the hollow protruding portion  115  of the cell holder  110  is inserted into the open area  145  of the separation member  140 , the cooling channel F penetrating the open area  145  of the separation member  140  may be formed. To this end, the open area  145  of the separation member  140  may be formed at a position corresponding to the hollow protruding portion  115 , and may have a shape corresponding to the hollow protruding portion  115 . In an embodiment, the open area  145  may be formed in a circular shape corresponding to the hollow protruding portion  115  including the wall body  115   a  having a circular shape surrounding the hollow portion at the center. However, the technical scope of the disclosure is not limited thereto, and the open area  145  may have various shapes corresponding to the hollow protruding portion  115 , for example, various oval and polygonal shapes, e.g., a hexagonal shape. 
     Referring to  FIG. 7 , in an embodiment, the open area  145  may include a wall body  145   a  surrounding the outer circumferential of an opening and extending toward the hollow protruding portion  115 , and the wall body  115   a  of the hollow protruding portion  115  may be inserted into the wall body  145   a  of the open area  145 . In this state, the wall body  145   a  of the open area  145  and the wall body  115   a  of the hollow protruding portion  115  may be formed in a circular shape corresponding to each other at corresponding positions, and may extend toward each other to be assembled in an interference fit. For example, the outer circumferential of the wall body  115   a  of the hollow protruding portion  115  may be inserted into the inner circumference of the wall body  145   a  of the open area  145 , and the wall body  115   a  of the hollow protruding portion  115  and the wall body  145   a  of the open area  145  may be assembled in an interference fit with respect to each other. For example, the wall body  145   a  of the open area  145  may have an inner circumference of a size that is gradually decreased toward the hollow protruding portion  115 , or the wall body  115   a  of the hollow protruding portion  115  may have an outer circumference of a size that is gradually increased toward the open area  145 . As the wall body  145   a  of the open area  145  or the wall body  115   a  of the hollow protruding portion  115  each have a gradation in a protruding direction toward each other, the wall body  145   a  of the open area  145  and the wall body  115   a  of the hollow protruding portion  115  may be assembled in an interference fit with respect to each other in a direction of being inserted into each other. 
     Referring to  FIGS. 6 and 7 , the open area  145  of each of the upper and lower separation members  140   a  and  140   b  may be formed at positions corresponding to each other to form the cooling channel F that penetrates at least a part of the battery pack. The open area  145  of each of the upper and lower separation members  140   a  and  140   b  may form the cooling channel F that penetrates almost the entire structure of the battery pack, with the hollow protruding portion  115  of the cell holder  110  provided between the upper and lower separation members  140   a  and  140   b , and with the open area  135  of the circuit board  130  provided between the upper and lower separation members  140   a  and  140   b  with the cell holder  110 . In detail, the cooling channel F may be connected from the upper separation member  140   a  to the lower separation member  140   b  by penetrating the circuit board  130 , the upper and lower holders  110   a  and  110   b , and the battery cells  10  inserted into the upper and lower holders  110   a  and  110   b , thereby penetrating almost the entire structure of the battery pack in the vertical direction. To this end, the upper and lower separation members  140   a  and  140   b  and the open area  135  of the circuit board  130  may be formed at positions corresponding to each other, and at a position corresponding to the hollow protruding portion  115  so that the hollow protruding portion  115  of the cell holder  110  is inserted therein. 
     The separation member  140  may include the shield area  144  formed at a position corresponding to the vent portion  13  of each of the battery cells  10 . In the following description, the shield area  144  formed in the upper separation member  140   a  is mainly described. However, the technical matters of the upper separation member  140   a  described below may be substantially identically applied to the lower separation member  140   b.    
     Referring to  FIG. 8 , the shield area  144  may be formed in a shape to close, e.g., completely overlap tops of, the upper portion of the vent portion  13  so that the discharge gas DG discharged from the vent portion  13  of each of the battery cells  10 , or the terminal hole  112  that exposes the vent portion  13 , is not leaked by penetrating the separation member  140 . For example, the shield area  144  may be formed in a closed shape, e.g., as a solid and flat plate with the exception of the open area  145 , not such that a part of the separation member  140  is opened, as in the open area  145 , to be in fluid communication with the upper and lower portions of the separation member  140 , but such that the upper and lower portions of the separation member  140  are not in fluid communication with each other through the shield area  144  and are separated from each other. As the shield area  144  is formed in a closed shape, the lower portion of the shield area  144  where the vent portion  13 , or the terminal hole  112  that exposes the vent portion  13 , is disposed, may not be in fluid communication with the upper portion of the shield area  144  with respect to the shield area  144 . 
     As such, as the lower portion of the shield area  144  where the vent portion  13 , or the terminal hole  112  that exposes the vent portion  13 , is disposed, and the upper portion of the shield area  144  are not fluidically connected to each other to be separated from each other with respect to the shield area  144 , the discharge gas DG discharged from the vent portion  13 , or the terminal hole  112  that exposes the vent portion  13 , may not be leaked to the upper portion of the shield area  144  by penetrating the shield area  144 . The discharge gas DG discharged from the vent portion  13 , or the terminal hole  112  that exposes the vent portion  13 , may be blocked by the shield area  144  so as to flow along the discharge path DP, e.g., in an area defined between the shield area  144  and tops of the battery cells  10 , and may be discharged, e.g., only, along the discharge path DP to the outside of the battery pack. 
     The shield area  144  may not be limited to a position corresponding to the vent portion  13  of each of the battery cells  10 , or the terminal hole  112  that exposes the vent portion  13 , and may be formed across the entire area of the separation member  140 , except the open area  145 . For example, the shield area  144  may extend to the entire area of the separation member  140  across an area between the open areas  145 , except the open area  145  for penetration of the cooling channel F, thereby forming the discharge path continuously connected from the position corresponding to the vent portion  13 , or the terminal hole  112  that exposes the vent portion  13 , to the discharge hole DH. For example, the discharge gas DG discharged from the vent portions  13 , or the terminal holes  112  that expose the vent portion  13 , different from each other, may be gathered to the discharge hole DH along the discharge path continuously formed between the shield area  144  of the separation member  140  and the battery cells  10 . In an embodiment, the discharge path may be formed between the shield area  144  of the separation member  140  and the battery cells  10  or between the shield area  144  of the separation member  140  and the cell holder  110 , or circuit board  130 , and may be continuously formed from each vent portion  13  of each of the battery cells  10 , or each terminal hole  112  that exposes the vent portion  13 , to the discharge hole DH formed at one side of the cell holder  110 . For example, the discharge path may be formed in a shape such that a space between the hollow protruding portion  115  inserted into the open area  145  of the separation member  140  is continuously connected. The discharge gas DG gathered to the discharge hole DH through the discharge path may be discharged to the outside of the battery pack. 
     As such, the discharge path having one side closed by the shield area  144  formed in a close shape to prevent connection between the upper and lower portions of the separation member  140  may be spatially separated from the cooling channel F that penetrates the upper and lower portions of the separation member  140  through the open area  145  of the separation member  140 . In detail, the separation member  140  may be formed in a plate shape, particularly in a closed plate shape, except the open area  145  that is opened to allow the hollow protruding portion  115  to be inserted therein. In this state, the cooling channel F surrounded by the hollow protruding portion  115  may penetrate the separation member  140  via the open area  145  and may be spatially separated from the discharged path formed between the separation member  140 , or the shield area  144 , and the battery cells  10 . Accordingly, owing to the structure in which the cooling channel F and the discharge path are spatially separated from each other, a risk of safety accidents as the coolant CM flowing along the cooling channel F and the discharge gas DG having a high temperature and a high pressure and flowing along the discharge path are mixed with each other, causing explosion or fire, may be reduced. In a battery pack mounted on an electric vehicle, as the discharge gas DG is prevented from being introduced into the interior of the vehicle by penetrating the separation member  140 , safety of a passenger may be obtained against a toxic gas. 
     Referring to  FIG. 9 , an upper duct  150   a  and a lower duct  150   b  may be disposed on the upper separation member  140   a  and the lower separation member  140   b , respectively. An opening OP for introducing the coolant may be formed in the upper duct  150   a . The coolant introduced into the battery pack through the opening OP may pass along the cooling channel F formed from the upper separation member  140   a  to the lower separation member  140   b , thereby cooling the battery cells  10 . The cooling channel F may be formed between the battery cells  10  neighboring to each other, and may cool the battery cells  10  by moving up and down in the length direction of the battery cells  10 . 
     The fluid device for generating a pressure difference between the inside and the outside of the battery pack may be connected to the lower duct  150   b  to forcibly allow a flow of the coolant to pass the battery pack. For example, the connection portion M of the fluid device may be formed at one side of the lower duct  150   b . In an embodiment, the fluid device may be provided as a suction type pump to form the pressure in the battery pack to be a negative pressure, with respect to the outside atmosphere of the battery pack. The fluid device connected to the lower duct  150   b  may be formed at an outlet of the coolant introduced through the opening OP of the upper duct  150   a . In other words, the opening OP of the upper duct  150   a  may form an inlet of the coolant, and the fluid device connected to the lower duct  150   b  may form the outlet of the coolant. In another embodiment, the fluid device may be provided as a pump of a blower type. In this case, the fluid device connected to the lower duct  150   b  may form the input of the coolant, and the opening OP of the upper duct  150   a  may form the output of the coolant. 
     As a negative pressure is formed in the battery pack according to the operation of the fluid device, due to a pressure difference between the inside and outside of the battery pack, the coolant may be introduced into the inside of the battery pack through the opening OP of the upper duct  150   a . The coolant introduced into the inside of the battery pack may penetrate the cooling channel F and cool the battery cells  10 , and may be discharged to the outside of the battery pack through the fluid device connected to the connection portion M of the lower duct  150   b.    
     In an embodiment, the opening OP formed in the upper duct  150   a  and the fluid device connected to the lower duct  150   b  may form an inlet and an outlet of the coolant, respectively. Accordingly, the position of the opening OP formed in the upper duct  150   a  and the position of the fluid device connected to the lower duct  150   b , or the position of the connection portion M formed in the lower duct  150   b , may be located at diagonal positions in an oblique direction across the battery pack. As such, a flow of the coolant entirely passing the inside of the battery pack may be induced through the opening OP of the upper duct  150   a  and the fluid device of the lower duct  150   b , which are formed at the diagonal positions of the battery pack. In detail, the position of the opening OP formed in the upper duct  150   a  and the position of the fluid device connected to the lower duct  150   b , or the position of the connection portion M formed in the lower duct  150   b , may be separated from each other in the long side portion direction of the battery pack. For example, when the position of the opening OP formed in the upper duct  150   a , for example, the position of at least some openings OP among the openings OP formed in the upper duct  150   a  are formed at one edge position in the long side portion direction of the battery pack, the position of the fluid device connected to the lower duct  150   b , or the position of the connection portion M formed in the lower duct  150   b , may be formed at the other edge position in the long side portion direction of the battery pack. As such, the opening OP formed in the upper duct  150   a  and the fluid device connected to the lower duct  150   b , or the connection portion M formed in the lower duct  150   b , are formed at one edge position and the other edge position in the long side portion direction of the battery pack, a flow of the coolant connecting the opening OP of the upper duct  150   a  to the fluid device of the lower duct  150   b  may be formed to cross the entire inside of the battery pack. 
     According to an embodiment, as a coolant flowing along a cooling channel from a discharge path of a discharge gas discharged through a vent portion of a battery cell are spatially separated, a battery pack having improved safety to fundamentally remove risk of explosion or fire due to a mixing of the coolant and the discharge gas may be provided. Furthermore, in a battery pack mounted on an electric vehicle, a discharge gas may be prevented from being introduced into the interior of the vehicle along an uncontrolled discharge path. 
     Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of ordinary skill in the art as of the filing of the present application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.