Patent Publication Number: US-2021167467-A1

Title: Battery module including module bus bar

Description:
TECHNICAL FIELD 
     The present disclosure relates to a battery module including a module bus bar, and more particularly, to a method of manufacturing a battery module to reduce the current loss and improve the manufacturing efficiency. 
     The present application claims priority to Korean Patent Application No. 10-2018-0114299 filed on Sep. 21, 2018 in the Republic of Korea, the disclosures of which are incorporated herein by reference. 
     BACKGROUND ART 
     In recent years, the demand for portable electronic products such as notebooks, video cameras, mobile phones, or the like is rapidly increasing, and the development of electric vehicles, energy storage batteries, robots, satellites, or the like is in earnest. For this reason, high-performance secondary batteries enabling repeated charging and discharging are being actively researched. 
     Secondary batteries currently commercialized include nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries, lithium secondary batteries and so on. Among them, the lithium secondary batteries are more highlighted in comparison to nickel-based secondary batteries due to advantages such as free charging and discharging, caused by substantially no memory effect, very low self-discharge rate, and high energy density. 
     The lithium secondary battery mainly uses lithium-based oxides and carbonaceous materials as a positive electrode active material and a negative electrode active material, respectively. In addition, the lithium secondary battery includes an electrode assembly in which a positive electrode plate coated with the positive electrode active material and a negative electrode plate coated with the negative electrode active material are disposed with a separator being interposed therebetween, and an exterior hermetically containing the electrode assembly together with an electrolyte. 
     In using the secondary battery, it is very important to check the temperature, current and voltage of the secondary battery in terms of preventing the occurrence of safety accidents and improving the secondary battery life. 
     In other words, as the performance of electronic devices improves day by day, the performance of secondary batteries for supplying a high output power at one time is also improving. In particular, since the secondary batteries used in the high-power electronic devices generate a large amount of heat, an accident such as ignition or explosion may be caused if the temperature rise is not properly handled. 
     To this end, a battery management unit applied to the electronic device may include a negative temperature coefficient (NTC) device, a positive temperature coefficient device (PTC) element, or the like as a temperature element used for measuring the temperature of a plurality of secondary batteries. 
     In addition, the conventional battery module includes an electrically conductive bus bar plate for electrically connecting the plurality of secondary batteries in series or in parallel. Further, generally, the bus bar plate is electrically connected to the battery management unit to control charging and discharging of the plurality of secondary batteries or to transfer the power of the plurality of secondary batteries to an external electronic device through an external input/output terminal. 
     Recently, the bus bar plate provided to the battery module uses a material with a relatively high electric resistance in order to increase the weldability of resistance welding with an electrode terminal. 
     However, the bus bar plate with a high electric resistance may be a factor that increases a current loss in transmitting the current generated in the secondary battery to an external device, thereby deteriorating the energy efficiency. In addition, as the material has a higher electric resistance, the thermal conductivity is lowered, which may reduce the heat dissipation performance of the battery module to the bus bar plate is applied. 
     On the contrary, if the bus bar plate uses a material with a low electric resistance, when the electrode terminal and the bus bar plate are bonded by means of resistance welding, it is difficult to generate sufficient resistance heat, resulting in poor weldability and long welding time. Accordingly, the manufacturing cost increases and the durability of the battery module deteriorates. 
     Further, if a thick metal plate is used to reduce electric resistance, it takes a long time to raise the welding temperature of the thick metal plate above a predetermined temperature, and a lot of heat sources must be added. Thus, it is very difficult to directly bond a cylindrical battery cell and a thick metal plate in by means of resistance welding. 
     DISCLOSURE 
     Technical Problem 
     The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to providing a battery module, which may reduce the current loss and improve the manufacturing efficiency. 
     These and other objects and advantages of the present disclosure may be understood from the following detailed description and will become more fully apparent from the exemplary embodiments of the present disclosure. Also, it will be easily understood that the objects and advantages of the present disclosure may be realized by the means shown in the appended claims and combinations thereof. 
     Technical Solution 
     In one aspect of the present disclosure, there is provided a battery module, comprising: 
     a plurality of cylindrical battery cells respectively having electrode terminals formed at an upper portion and a lower portion thereof; 
     a module housing including an accommodation portion having a plurality of hollow structures in which the plurality of cylindrical battery cells are inserted and accommodated; and a module bus bar including a first metal plate having a body portion located at an upper portion or a lower portion of the plurality of cylindrical battery cells to extend in a horizontal direction and a plurality of connection portions configured to extend in a horizontal direction from one side of the body portion to contact the electrode terminals of the plurality of cylindrical battery cells, and a second metal plate bonded to the body portion of the first metal plate and having a metal with a relatively higher electric conductivity than the first metal plate. 
     Also, the second metal plate may be bonded to the body portion of the first metal plate by cladding. 
     Moreover, a coupling protrusion protruding toward the body portion of the first metal plate may be formed at an outer surface of the second metal plate facing the body portion of the first metal plate. 
     In addition, a coupling groove dented inward may be formed at the body portion of the first metal plate so that the coupling protrusion is inserted and fixed therein. 
     Further, an insert portion having a support wall protruding outward may be formed at the body portion of the first metal plate so that at least a portion of the second metal plate is inserted therein. 
     Also, an accommodation groove dented in an inner direction of the body portion may be formed at the second metal plate to surround at least a portion of the body portion of the first metal plate. 
     Moreover, the connection portion of the first metal plate may have a relatively smaller thickness than the second metal plate. 
     In addition, the module bus bar may further include a third metal plate having a bonding portion bonded to an outer surface of the second metal plate and a plurality of connection extensions extending in a horizontal direction from one side of the bonding portion to contact the electrode terminals of the plurality of cylindrical battery cells. 
     Also, the connection portion of the first metal plate and the connection extension of the third metal plate may be disposed to be spaced apart by a predetermined distance. 
     Moreover, the second metal plate may have a protrusion configured to protrusively extend outward from the body portion of the first metal plate, and a fixing groove may be formed at the protrusion so that an external input/output terminal is inserted and fixed therein. 
     In addition, the module housing may have a mounting portion formed at an outer side thereof so that the module bus bar is mounted thereto. Further, a hook structure may be formed at the mounting portion to press and fix the module bus bar mounted on the mounting portion inward. 
     Also, in another aspect of the present disclosure, there is also provided a battery pack, comprising at least two battery modules according to the present disclosure. 
     Further, in another aspect of the present disclosure, there is also provided an device, comprising the battery pack according to the present disclosure. 
     In addition, in another aspect of the present disclosure, there is also provided a method for manufacturing a module bus bar, comprising: 
     a shaping step of shaping a first metal plate by rolling a body portion extending in a direction along which a plurality of cylindrical battery cells are arranged and a connection portion configured to electrically connect the plurality of cylindrical battery cells by using a pressing roller; 
     a bonding step of rolling a second metal plate having a higher electric conductivity than the first metal plate on the body portion of the first metal plate at a predetermined temperature to be bonded thereto by cladding; and a punching step of punching the body portion of the first metal plate by using a die to form the connection portion extending in a horizontal direction therefrom. 
     Further, in the bonding step, a coupling protrusion formed at the second metal plate to protrude toward the first metal plate may be inserted into and coupled to the body portion of the first metal plate. 
     Also, the method may further comprise a forming step of forming an external input/output terminal of the second metal plate by punching using a die. 
     Advantageous Effects 
     According to an embodiment of the present disclosure, in the battery module of the present disclosure, since the second metal plate has a metal with a higher electric conductivity than the metal of the first metal plate, it is possible to reduce the current loss of the module bus bar, thereby reducing the power loss of the battery module. Moreover, the second conductive metal plates with a higher electric conductivity has a relatively higher thermal conduction rate and a faster cooling rate than the first metal plate. As a result, this helps the heat dissipation of the battery module to greatly increase the cooling efficiency of the battery module. 
     In addition, according to another embodiment of the present disclosure, since the second metal plate is clad-bonded to the body portion of the first metal plate, the electrical connection between the second metal plate and the body portion of the first metal plate is very excellent, and the bonding (coupling) between the second metal plate and the body portion of the first metal plate is excellent, thereby preventing the durability of the module bus bar from being weakened. 
     Moreover, according to another embodiment of the present disclosure, since a coupling protrusion is formed on the outer surface of the second metal plate and a coupling groove formed at the body portion of the first metal plate, the second metal plate may be bonded to the body portion of the first metal plate with a strong bonding force. In particular, when bonding the second metal plate on the body portion of the first metal plate by rolling, the coupling protrusion may have an increased contact area with the second metal plate, when compared with the module bus bar of  FIG. 3 , thereby exhibiting a high coupling force and allowing relatively well metal mingling at the bonding portion. 
     In addition, according to another embodiment of the present disclosure, since an insert portion having a support wall is formed at the body portion of the first metal plate, the second metal plate may be primarily placed and fixed thereto. In particular, when bonding the second metal plate on the body portion of the first metal plate by rolling, the protrusion of the insert portion may be stably supported and fixed so that the second metal plate is bonded in place. Further, when compared with the module bus bar of  FIG. 3 , the insert portion may increase the contact area with the second metal plate, thereby ensuring the high bonding force and reducing the electric resistance that may occur at the bonding portion. 
     Also, according to an embodiment of the present disclosure, since an accommodation groove dented in the inner direction of the body is formed at the second metal plate, the second metal plate may be stably placed and coupled. In particular, when bonding the second metal plate on the body portion of the first metal plate by rolling, the second metal plate may be primarily fixed on the body portion of the first metal plate before the second metal plate is bonded in place, thereby facilitating the bonding process. 
     Moreover, according to another embodiment of the present disclosure, since the connection portion of the first metal plate is configured to have a thin thickness, the welding between the connection portion and the electrode terminal of the cylindrical battery cell may be performed quickly at a low process temperature. That is, during resistance welding, as the connection portion is thinner, the connection portion may be quickly melted at a lower temperature, compared to a thick connection portion. Accordingly, the efficiency of the manufacturing process may be increased, and the failure of the cylindrical battery cell according to the welding temperature may be minimized. 
     In addition, according to another embodiment of the present disclosure, when the connection portion of the first metal plate and the connection extension of the third metal plate are disposed to be spaced apart at a predetermined distance so as to be resistance-welded to the electrode terminals of the cylindrical battery cell, compared with the current path between the connection portions of the first metal plate, the current path between the connection portion of the first metal plate and the connection extension of the third metal plate is longer and the electric resistance is higher, so that the current may be concentrated in the current path from the connection portion of the first metal plate to the electrode terminal of the cylindrical battery cell and the connection extension of the third metal plate. Accordingly, the resistance welding between the module bus bar and the electrode terminal may be efficiently performed. In addition, it is possible to shorten the manufacturing time and to manufacture a battery module with excellent weldability. 
     Further, according to another embodiment of the present disclosure, when the protrusion is formed such that the external input/output terminal is coupled to the second metal plate rather than the first metal plate, power may be transmitted to an electronic device through the second metal plate having a relatively higher electric conductivity than the first metal plate, thereby minimizing the loss of power supplied from the battery module. In addition, since the second metal plate has more excellent heat dissipation characteristics than the first metal plate, the second metal plate is more advantageous for dissipating the heat generated in the external input/output terminal to the outside. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       The accompanying drawings illustrate a preferred embodiment of the present disclosure and together with the foregoing disclosure, serve to provide further understanding of the technical features of the present disclosure, and thus, the present disclosure is not construed as being limited to the drawing. 
         FIG. 1  is a perspective view schematically showing components of a battery module according to an embodiment of the present disclosure. 
         FIG. 2  is an exploded perspective view schematically showing exploded components of the battery module according to an embodiment of the present disclosure. 
         FIG. 3  is a schematic sectional view showing a module bus bar, taken along the line C-C′ of  FIG. 1 . 
         FIG. 4  is a sectional view schematically showing a module bus bar of the battery module according to another embodiment of the present disclosure. 
         FIG. 5  is a sectional view schematically showing a module bus bar of the battery module according to still another embodiment of the present disclosure. 
         FIG. 6  is a sectional view schematically showing a module bus bar of the battery module according to still another embodiment of the present disclosure. 
         FIG. 7  is a perspective view schematically showing a module bus bar of the battery module according to still another embodiment of the present disclosure. 
         FIG. 8  is a schematic sectional view showing the module bus bar, taken along the line D-D′ of  FIG. 7 . 
         FIG. 9  is a perspective view schematically showing components of a battery module according to another embodiment of the present disclosure. 
     
    
    
     BEST MODE 
     Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Prior to the description, it should be understood that the terms used in the specification and the appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present disclosure on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation. 
     Therefore, the description proposed herein is just a preferable example for the purpose of illustrations only, not intended to limit the scope of the disclosure, so it should be understood that other equivalents and modifications could be made thereto without departing from the scope of the disclosure. 
       FIG. 1  is a perspective view schematically showing components of a battery module according to an embodiment of the present disclosure. Also,  FIG. 2  is an exploded perspective view schematically showing exploded components of the battery module according to an embodiment of the present disclosure. 
     Referring to  FIGS. 1 and 2 , a battery module  200  according to an embodiment of the present disclosure may include a plurality of cylindrical battery cells  100 , a module housing  220 , and a module bus bar  210 . 
     Here, the cylindrical battery cell  100  may include a cylindrical battery can  120  and an electrode assembly (not shown) accommodated in the battery can  120 . 
     Also, the battery can  120  may include a material with high electrical conductivity. For example, the battery can  120  may include aluminum, or copper. 
     Moreover, the battery can  120  may be configured to stand long in a vertical direction. In addition, the battery can  120  may have a cylindrical shape extending in the vertical direction. Further, an electrode terminal  111  and an electrode terminal  112  may be formed at an upper portion and a lower portion of the battery can  120 , respectively. Specifically, a positive electrode terminal  111  may be formed at a flat circular top surface of the upper end of the battery can  120 , and a negative electrode terminal  112  may be formed at a bottom flat surface of the lower end of the battery can  120 . 
     Further, the cylindrical battery cell  100  may be arranged in a plurality of columns and rows in a horizontal direction. Here, the horizontal direction may mean a direction parallel to the ground when the cylindrical battery cell  100  is placed on the ground, and may also be referred to as at least one direction on a plane perpendicular to the vertical direction. Also, the horizontal direction may refer to X and Y directions of  FIG. 1 . For example, as shown in  FIG. 2 , the battery module  200  may include a plurality of cylindrical battery cells  100  arranged in five rows in a left and right direction (x direction) and three rows in a front and rear direction (y direction). 
     In addition, an electrode assembly (not shown) may be formed such that a positive electrode and a negative electrode are wound in a jelly-roll form with a separator being interposed therebetween. Further, a positive electrode tab may be attached to the positive electrode (not shown) to be connected to a positive electrode terminal  111  at the upper end of the battery can  120 . A negative electrode tab may be attached to the negative electrode (not shown) to be connected to a negative electrode terminal  112  at the lower end of the battery can  120 . 
     Meanwhile, the module housing  220  may have accommodation portions  220   s   1 ,  220   s   2  in which the cylindrical battery cell  100  may be inserted and accommodated. Specifically, the accommodation portions  220   s   1 ,  220   s   2  may have a plurality of hollow structures formed to cover an outer surface of the cylindrical battery cell  100 . In this case, the module housing  220  may have an electrically insulating material. For example, the electrically insulating material may be a polymer plastic. More specifically, the electrically insulating material may be polyvinyl chloride (PVC). 
     Also, referring to  FIG. 1 , the module housing  220  may include an outer wall  220   d  provided at front, rear, left and right sides to form an inner space therein. In addition, referring to  FIG. 2 , the upper case  220   a  and the lower case  220   b  may have a perforated hole  220   h  so that a fastening bolt  228  is inserted therein. 
     For example, as shown in  FIG. 1 , the upper case  220   a  and the lower case  220   b  of the module housing  220  may respectively have a perforated hole  220   h  into which the bolt  228  is inserted and fixed. Accordingly, the upper case  220   a  and the lower case  220   b  may be fastened and coupled by means of the bolt  228  inserted into the perforated hole  220   h.    
     Meanwhile, referring to  FIGS. 1 to 3 , the module bus bar  210  may be configured to electrically connect the plurality of cylindrical battery cells  100 . For example, the module bus bar  210  may be configured to electrically connect the plurality of cylindrical battery cells  100  in series. Alternatively, the module bus bar  210  may be configured to electrically connect the plurality of cylindrical battery cells  100  in parallel. The module bus bar  210  may have a metal with excellent electric conductivity. 
     In addition, the module bus bar  210  may include a first metal plate  212  and a second metal plate  214 . Specifically, the first metal plate  212  may have a body portion  212   a  located at an upper portion or a lower portion of the plurality of cylindrical battery cells  100  to extend in a horizontal direction. Further, the body portion  212   a  may be disposed between the plurality of cylindrical battery cells  100  arranged in two rows. The body portion  212   a  may have a rectangular plate shape with a predetermined thickness. 
     Also, the first metal plate  212  may have a plurality of connection portions  212   b  respectively extending in a horizontal direction from both sides of the body portion  212   a  to contact the electrode terminals  111  of the plurality of cylindrical battery cells  100  from one side of the body portion  212   a . That is, the connection portion  212   b  may be formed to extend from a side of the body portion  212   a  in the horizontal direction (the x direction of  FIG. 1 ) to contact an upper surface of the electrode terminals  111  of the plurality of cylindrical battery cells  100 . 
     For example, as shown in  FIG. 3 , the module bus bar  210  may include one first metal plate  212 . In addition, the first metal plate  212  may have a body portion  212   a  located on the upper or lower portion of the plurality of cylindrical battery cells  100  to extend in a horizontal direction (the x direction of  FIG. 1 ) and a plurality of connection portions  212   b  extending in a horizontal direction to contact the electrode terminals  111  of the plurality of cylindrical battery cells  100  from one side of the body portion  212   a.    
     Further, according to one aspect of the present disclosure, the connection portion  212   b  of the module bus bar  210  in electrical contact with the electrode terminal  111  of the cylindrical battery cell  100  may be formed to be branched to two regions. In this case, during the welding process between the connection portion  212   b  and the electrode terminals  111 , the thermal conductivity for welding heating may be effectively increased through a gap of the branched structure, thereby shortening the welding time and improving the welding reliability. 
     In addition, the second metal plate  214  may be bonded to the body portion  212   a  of the first metal plate  212 . Further, the second metal plate  214  may have a rectangular plate shape, similar to the body portion  212   a  of the first metal plate  212 . For example, as shown in  FIG. 3 , the second metal plate  214  may be bonded onto the body portion  212   a  of the first metal plate  212 . Thus, the second metal plate  214  may have a rectangular plate shape extending along the extending direction of the body portion  212   a.    
     Also, the second metal plate  214  may have a metal with a relatively higher electric conductivity than the first metal plate  212 . Specifically, the second metal plate  214  may be made of a metal with a relatively higher electric conductivity than the first metal plate  212 . Moreover, the second metal plate  214  may be configured to have a relatively higher electrical conductivity than the first metal plate  212 . 
     For example, the first metal plate  212  may have a nickel material, and the second metal plate  214  may have a copper material. However, without being limited to the above, the first metal plate  212  and the second metal plate  214  may be made of any metal alloy mainly containing nickel, gold, silver or the like, if the second metal plate  214  may be configured to have a relatively higher electrical conductivity than the first metal plate  212 . 
     In other words, the first metal plate  212  may have a metal with a relatively higher resistivity than the second metal plate  214 . For example, the metal with high resistivity may be nickel. 
     Thus, according to this configuration of the present disclosure, since the second metal plate  214  has a metal with a relatively higher electric conductivity than the metal of the first metal plate  212 , it is possible to reduce the current loss of the module bus bar  210  and the power loss of the battery module  200 . Moreover, the second metal plate  214  with a higher electric conductivity has a relatively higher thermal conductivity and a faster cooling rate than the first metal plate  212 . Accordingly, this helps the heat dissipation of the battery module  200 , thereby greatly increasing the cooling efficiency of the battery module  200 . 
     On the contrary, since the first metal plate  212  has a metal with a higher resistivity than the second metal plate  214 , when the connection portion  212   b  of the first metal plate  212  is resistance-welded with the electrode terminal  111  of the cylindrical battery cell  100 , high resistance heat may be generated at the welding portion due to the high resistivity metal, thereby improving the efficiency of the welding process. 
     In addition, the connection portion  212   b  may be branched into two regions. That is, the connection portion  212   b  may have a form in which a gap of a predetermined distance is formed between two branched plate shapes. For example, as shown in  FIG. 1 , the connection portion  212   b  may be formed to protrude in a horizontal direction to have a form branched into two regions (a separated structure) from the body portion  212   a  of the first metal plate  212 . 
     Meanwhile, referring to  FIG. 3  again, the second metal plate  214  may be bonded to the body portion  212   a  of the first metal plate  212  by cladding. Here, the portion where the body portion  212   a  of the second metal plate  214  and the first metal plate  212  is bonded by cladding may be in a state where the metal of the second metal plate  214  and the metal of the body portion  212   a  of the first metal plate  212  are bonded to each other. 
     That is, in the process of rolling and bonding the second metal plate  214  and the body portion  212   a  of the first metal plate  212  to each other at a predetermined temperature, a part of the metal of the second metal plate  214  and a part of the metal of the body portion  212   a  of the first metal plate  212  may be coupled and mingled with each other. 
     Thus, according to this configuration of the present disclosure, since the second metal plate  214  is bonded to the body portion  212   a  of the first metal plate  212  by cladding, the electrical connection between the second metal plate  214  and the body portion  212   a  of the first metal plate  212  is very excellent, and the bonding (coupling) between the second metal plate  214  and the body portion  212   a  of the first metal plate  212  is excellent, thereby preventing the durability of the module bus bar  210  from being weakened. 
       FIG. 4  is a sectional view schematically showing a module bus bar of the battery module according to another embodiment of the present disclosure. 
     Referring to  FIG. 4 , a module bus bar  210 B according to another embodiment may have a coupling protrusion  212   p  protruding toward the body portion  212   a  of the first metal plate  212 B and formed at an outer surface of the second metal plate  214 B facing the body portion  212   a  of the first metal plate  212 B. In addition, the coupling protrusion  212   p  may have an uneven structure. 
     However, the shape of the coupling protrusion  212   p  is not limited to the uneven structure, and any shape may be applied as long as the coupling protrusion  212   p  may be inserted into and fixed to the body portion  212   a  of the first metal plate  212 B to increase the coupling force therebetween. 
     Further, a coupling groove  212   h  dented inward may be formed at the body portion  212   a  of the first metal plate  212 B so that the coupling protrusion  212   p  is inserted and fixed therein. Specifically, the coupling groove  212   h  may have a dented structure corresponding to the outer shape of the coupling protrusion  212   p.    
     For example, as shown in  FIG. 4 , nine coupling protrusions  212   p  protruding downward may be formed on the outer surface of the second metal plate  214 B facing the body portion  212   a  of the first metal plate  212 B. In addition, nine coupling grooves  212   h  dented inward in a shape corresponding to the nine coupling protrusions  212   p  may be formed at the body portion  212   a  of the first metal plate  212 B. 
     Thus, according to this configuration of the present disclosure, since the coupling protrusion  212   p  is formed on the outer surface of the second metal plate  214 B and the coupling groove  212   h  is formed at the body portion  212   a  of the first metal plate  212 B, the second metal plate  214 B may be bonded to the body portion  212   a  of the first metal plate  212 B with a strong bonding force. In particular, when the second metal plate  214 B is bonded onto the body portion  212   a  of the first metal plate  212 B by rolling, the coupling protrusion  212   p  may have an increased contact area (bonding area) with the second metal plate  214 B, compared to the module bus bar  210  of  FIG. 3 , thereby exhibiting a high bonding strength and allowing relatively good metal mingling at the bonding portion. 
       FIG. 5  is a sectional view schematically showing a module bus bar of the battery module according to still another embodiment of the present disclosure. 
     Referring to  FIG. 5 , a module bus bar  210 C according to another embodiment may have an insert portion  212   i  formed at the body portion  212   a  of the first metal plate  212 C so that at least a portion of the second metal plate  214  is inserted therein. Specifically, the insert portion  212   i  may have a support wall  212   w  protruding outward. 
     For example, as shown in  FIG. 5 , an insert portion  212   i  having an insertion space may be formed at the body portion  212   a  of the first metal plate  212 C so that a portion of the second metal plate  214  is inserted therein. In addition, two support walls  212   w  protruding upward may be formed at the insert portion  212   i  to support both horizontal sides of the second metal plate  214 . 
     Thus, according to this configuration of the present disclosure, since the insert portion  212   i  having the support wall  212   w  is formed at the body portion  212   a  of the first metal plate  212 C, the second metal plate  214  may be primarily placed and fixed. In particular, when rolling the second metal plate  214  on the body portion  212   a  of the first metal plate  212 C, the protrusion of the insert portion  212   i  may be stably supported and fixed so that the second metal plate  214  is bonded in place. Moreover, since the insert portion  212   i  may increase the contact area with the second metal plate  214 , compared to the module bus bar  210  of  FIG. 3 , it is possible to ensure the high bonding force and reduce the electric resistance that may occur at the bonding portion. 
       FIG. 6  is a sectional view schematically showing a module bus bar of the battery module according to still another embodiment of the present disclosure. 
     Referring to  FIG. 6 , a second metal plate  214 D included in a module bus bar  210 D according to another embodiment may have an accommodation groove  214   h  dented in an inner direction of the body portion. Specifically, the accommodation groove  214   h  may have an inner space capable of surrounding at least a portion of the body portion  212   a  of the first metal plate  212 D. For example, as shown in  FIG. 6 , the accommodation groove  214   h  dented inward may be formed at the second metal plate  214 D to surround portions of left and right horizontal sides of the body portion  212   a  of the first metal plate  212 D and a top surface thereof. 
     Thus, according to this configuration of the present disclosure, since the accommodation groove  214   h  dented in the inner direction of the body portion is formed at the second metal plate  214 D, the second metal plate  214 D may be stably placed and coupled. In particular, when rolling the second metal plate  214 D onto the body portion  212   a  of the first metal plate  212 D, the second metal plate  214 D may be fixed primarily on the body portion  212   a  of the body portion  212 D before the second metal plate  214 D is bonded in place, thereby facilitating the bonding process. 
     Moreover, compared with the module bus bar  210  of  FIG. 3 , the accommodation groove  214   h  may increase the contact area between the body portion  212   a  and the second metal plate  214 D, thereby ensuring the high bonding force and reducing the electric resistance that may occur at the bonding portion. 
     Meanwhile, referring to  FIG. 3  along with  FIG. 3 , the connection portion  212   b  of the first metal plate  212  may have a thickness T1 relatively thinner than the second metal plate  214 . Here, the thickness T1 means a thickness T1 in a direction (vertical direction) in which the connection portion  212   b  faces the electrode terminal  111  of the cylindrical battery cell  100 . 
     Specifically, it is appropriate that the connection portion  212   b  of the first metal plate  212  is rapidly melted during welding in order to be efficiently bonded to the electrode terminal  111  of the cylindrical battery cell  100 . Meanwhile, the second metal plate  214  may serve as a current path for transmitting a current transferred from the cylindrical battery cell  100  to an external electronic device, instead of a portion where welding is performed. To this end, the second metal plate  214  needs to reduce the electric resistance in order to minimize a current loss in transmitting the current. Accordingly, it is appropriate that the second metal plate  214  has a larger sectional area at a side where current flows. That is, the power loss may be reduced more as the thickness T2 of the second metal plate  214  is greater. 
     For example, as shown in  FIG. 3 , in the module bus bar  210  of the present disclosure, the thickness T1 of the connection portion  212   b  of the first metal plate  212  may be relatively thinner than a thickness T2 of the second metal plate  214 . 
     Thus, according to this configuration of the present disclosure, since the thickness T1 of the connection portion  212   b  of the first metal plate  212  is configured thin, the welding between the connection portion  212   b  and the electrode terminal  111  of the cylindrical battery cell  100  may be performed rapidly at a low process temperature. That is, during the resistance welding, as compared with the case where the connection portion is relatively thick, as the connection portion  212   b  is thinner, the connection portion  212   b  may be quickly melted at a lower temperature. Accordingly, the efficiency of the manufacturing process may be increased, and the failure of the cylindrical battery cell  100  according to the welding temperature may be minimized. 
       FIG. 7  is a perspective view schematically showing a module bus bar of the battery module according to still another embodiment of the present disclosure. Also,  FIG. 8  is a schematic sectional view showing the module bus bar, taken along the line D-D′ of  FIG. 7 . 
     Referring to  FIGS. 7 and 8  along with  FIG. 2 , a module bus bar  210 E according to another embodiment may further include a third metal plate  216 . Specifically, the third metal plate  216  may have a bonding portion  216   a  bonded to an outer surface of the second metal plate  214 . In addition, the bonding portion  216   a  may be located on the second metal plate  214 . Further, the bonding portion  216   a  may be disposed between the plurality of cylindrical battery cells  100  arranged in two rows. 
     In addition, the third metal plate  216  may have a plurality of connection extensions  216   b  formed to extend in a horizontal direction w from one side of the bonding portion  216   a . Further, each of the plurality of connection extensions  216   b  may be in contact with the electrode terminal  111  of each of the plurality of cylindrical battery cells  100 . 
     Also, the third metal plate  216  may have a metal with a relatively lower electric conductivity than the second metal plate  214 . For example, the third metal plate  216  may include a nickel material. Further, any metal alloy mainly containing nickel, aluminum, gold, silver, or the like may be applied to the third metal plate  216 . 
     For example, as shown in  FIG. 8 , the module bus bar  210 E of the present disclosure may include a first metal plate  212 , a second metal plate  214 , and a third metal plate  216 . In this case, the first metal plate  212  and the third metal plate  216  may mainly include nickel. In addition, the second metal plate  214  may mainly include copper. That is, the second metal plate  214  may have a higher electric conductivity than the first metal plate  212  and the third metal plate  216 . Further, the third metal plate  216  may have a bonding portion  216   a  bonded to the outer surface of the second metal plate  214  and a plurality of connection extensions  216   b  extending in a horizontal direction from one side of the bonding portion  216   a.    
     Accordingly, according to this configuration of the present disclosure, since the module bus bar  210 E according to another embodiment additionally includes the third metal plate  216 , the body portion  212   a  of the first metal plate  212 , the second metal plate  214 , and the bonding portion  216   a  of the third metal plate  216  may be bonded by rolling. Accordingly, the bonding force between the metal plates of the module bus bar  210 E is further improved, and the bonding area among the first metal plate  212  or the third metal plate  216  and the second metal plate  214  electrically connected to the cylindrical battery cell  100  is increased, thereby minimizing the electric resistance caused by bonding and reducing the current loss of the module bus bar  210 E. 
     Referring to  FIGS. 7 and 8  again, the module bus bar  210 E according to another embodiment may have a connection portion  212   b   1  of the first metal plate  212 , different from the connection portion  212   b  of the module bus bar  210  of  FIG. 3 . That is, in the module bus bar  210 E, the connection extension  216   b  of the third metal plate  216  may be disposed to be spaced apart from the connection portion  212   b   1  by a predetermined distance. That is, the connection portion  212   b   1  of the first metal plate  212  and the connection extension  216   b  of the third metal plate  216  may be spaced apart by a predetermined distance and arranged parallel to each other in a horizontal direction. 
     Further, the connection portion  212   b   1  of the first metal plate  212  and the connection extension  216   b  of the third metal plate  216  may be disposed to be spaced apart by a predetermined distance. In addition, the spaced distance between the connection portion  212   b   1  of the first metal plate  212  and the connection extension  216   b  of the third metal plate  216  may be set to generate proper resistance heat when being resistance-welded to the electrode terminal  111  of the cylindrical battery cell  100 . 
     Further, the connection portion  212   b   1  of the first metal plate  212  and the connection extension  216   b  of the third metal plate  216  may be made of the same material. For example, the connection portion  212   b   1  of the first metal plate  212  and the connection extension  216   b  of the third metal plate  216  may mainly include a nickel material. 
     Thus, according to this configuration of the present disclosure, if the connection portion  212   b   1  of the first metal plate  212  and the connection extension  216   b  of the third metal plate  216  are disposed to be spaced apart by a predetermined distance to be resistance-welded to the electrode terminal  111  of the cylindrical battery cell  100 , when compared to a current path between two connection portions  212   b   1  of the first metal plate  212 , a current path between the connection portion  212   b   1  of the first metal plate  212  and the connection extension  216   b  of the third metal plate  216  is longer and the electric resistance is higher, so that the current flow may be concentrated in the current path from the connection portion  212   b   1  of the first metal plate  212  to the electrode terminal  111  of the cylindrical battery cell  100  and the connection extension  216   b  of the third metal plate  216 . Accordingly, the resistance welding between the module bus bar  210 E and the electrode terminal may be efficiently performed. In addition, the manufacturing time may be shortened and the battery module  200  with excellent weldability may be manufactured. 
     Referring to  FIGS. 1 and 3 , the second metal plate  214  of the module bus bar  210 A of another embodiment of the present disclosure may include a protrusion  214   a  configured to protrude outward from the body portion  212   a  of the first metal plate  212 . Specifically, the protrusion  214   a  may have a coupling structure such that the external input/output terminal is coupled thereto. For example, the protrusion  214   a  may have a perforated fixing groove  214   b  into which the external input/output terminal (not shown) is inserted and coupled. In addition, the external input/output terminal may have a bolt shape that may be inserted into and fastened to the fixing groove  214   b.    
     For example, as shown in  FIG. 1 , the protrusion  214   a  may be formed on two module bus bars  210 A among six module bus bars  210 A. In addition, each of the protrusions  214   a  may have the fixing groove  214   b  to which the external input/output terminal (not shown) is coupled. 
     Therefore, according to this configuration of the present disclosure, when the protrusion  214   a  is formed such that the external input/output terminal is coupled to the second metal plate  214  rather than the first metal plate  212 , the power may be transmitted to an external electronic device through the second metal plate  214  with a higher electric conductivity than the first metal plate  212 , thereby minimizing the loss of power supplied from the battery module  200 . In addition, since the second metal plate  214  has more excellent heat dissipation characteristics than the first metal plate  212 , the second metal plate  214  is more advantageous in dissipating the heat generated in the external input/output terminal to the outside. 
       FIG. 9  is a perspective view schematically showing components of a battery module according to another embodiment of the present disclosure. 
     Referring to  FIG. 9 , a battery module  200 F according to another embodiment of the present disclosure may have a mounting portion  222  formed at the module housing  220  so that the module bus bar  210  is mounted to an outer side thereof. Specifically, the mounting portion  222  to which the module bus bar  210  may be mounted may be formed at an upper surface or a lower surface of the module housing  220 . That is, the mounting portion  222  to which the module bus bars  210 ,  210 A may be respectively mounted may be formed between the plurality of cylindrical battery cells  100  accommodated in the module housing  220 . In other words, the mounting portion  222  to which the module bus bars  210 ,  210 A may be respectively mounted may be formed between two accommodation portions in which the plurality of cylindrical battery cells  100  of the module housing  220  are accommodated. 
     In addition, a hook structure  222   k  may be formed at the mounting portion  222  to press and fix the module bus bar  210  mounted on the mounting portion  222  inward. Specifically, the hook structure  222   k  may have a body portion  222   k   1  protrusively extending outward from the upper surface or the lower surface of the module bus bar  210 , and a pressing portion  222   k   2  extending in the horizontal direction from an extending end of the body portion  222   k   1  to press the outer surface of the module bus bar  210 . 
     Thus, according to this configuration of the present disclosure, the module bus bar  210  pressurized by the hook structure is stably fixed to maintain the structure bonded to the electrode terminals  111 ,  112  of the plurality of cylindrical battery cells  100 . Moreover, it is possible to closely maintain the bonding state between the plurality of metal plates by the inward pressing force of the hook structure, thereby improving the durability of the module bus bar  210 . 
     In addition, a battery pack (not shown) according to the present disclosure may include at least two of the battery modules  200 . Specifically, the at least two battery modules  200  may be arranged in one direction. In some cases, the battery pack may further include a heatsink (not shown) for heat dissipation. 
     Also, an electronic device (not shown) according to the present disclosure may include the battery pack. For example, the battery pack may be accommodated in an external case of the electronic device. In addition, the electronic device may be a mobile means such as an electric bicycle or a power tool. 
     Meanwhile, referring to  FIGS. 1 to 3  again, a method for manufacturing the module bus bar  210  according to the present disclosure may include a shaping step, a bonding step, and a punching step. Specifically, in the shaping step, the connection portion  212   b  configured to electrically connect plurality of cylindrical battery cells  100  and the body portion  212   a  of the first metal plate  212  extending in a direction along which the plurality of cylindrical battery cells  100  arranged may be shaped by rolling using a pressing roller (not shown). 
     In addition, in the bonding step, the second metal plate  214  with a higher electric conductivity than the first metal plate  212  may be rolled and bonded onto the body portion  212   a  of the first metal plate  212  at a predetermined temperature by cladding. At this time, the rolling may be performed using a common heat treatment method. For example, the heat treatment temperature may be set in the range from a room temperature to a temperature lower than a melting point of nickel and copper. More specifically, the predetermined temperature may be 100 □ to 500□. In addition, in the punching step, punching may be performed using a die (not shown) to form the connection portion  212   b  extending in a horizontal direction from the body portion  212   a  of the first metal plate  212 . In this case, the die may be formed such that the connection portion  212   b  has a branched structure with a predetermined gap. 
     Thus, according to this configuration of the present disclosure, since the module bus bar  210  is configured such that the first metal plate  212  and the second metal plate  214  are bonded to each other by cladding, two advantages may be obtained over a bus bar made of a single metal plate. That is, the first metal plate  212  configured to be bonded to the plurality of cylindrical battery cells  100  has a metal with a relatively low electric conductivity than the second metal plate  214  and has a low heat dissipation property, thereby ensuring easy welding. In addition, since the second metal plate  214  includes a metal with a relatively higher electric conductivity than the first metal plate  212 , the current supplied from the plurality of cylindrical battery cells  100  may be transmitted with a minimized power loss. 
     In addition, since the module bus bar  210  is configured such that the first metal plate  212  and the second metal plate  214  are bonded to each other by cladding (metal mingling), the electric resistance generated at the bonding portion thereof may be minimized. 
     Meanwhile, referring to  FIG. 4  again, in the shaping step, the coupling protrusion  212   p  formed at the second metal plate  214  to protrude toward the first metal plate  212  may be inserted into and coupled to the body portion  212   a  of the first metal plate  212 . 
     In this case, the coupling protrusion  212   p  may have an uneven structure. However, the shape of the coupling protrusion  212   p  is not limited to the uneven structure, and any shape may be applied as long as the coupling protrusion  212   p  may be inserted into and fixed to the body portion  212   a  of the first metal plate  212 B to increase the coupling force therebetween. 
     Further, the coupling groove  212   h  dented inward may be formed at the body portion  212   a  of the first metal plate  212  so that the coupling protrusion  212   p  is inserted and fixed therein. Specifically, the coupling groove  212   h  may have a dented structure corresponding to the outer shape of the coupling protrusion  212   p.    
     Thus, according to this configuration of the present disclosure, since the coupling protrusion  212   p  is formed on the outer surface of the second metal plate  214  and the coupling groove  212   h  is formed at the body portion  212   a  of the first metal plate  212 , the second metal plate  214  may be bonded to the body portion  212   a  of the first metal plate  212  with a strong bonding force. Further, metal mingling may be relatively well achieved at the bonding portion of the second metal plate  214  and the body portion  212   a  of the first metal plate  212 . 
     Meanwhile, referring to  FIGS. 1 and 3  again, the manufacturing method may further include a forming step of forming the fixing groove  214  of the second metal plate  214  by punching using a die (not shown). 
     Specifically, the second metal plate  214  may have the protrusion  214   a  elongated to protrude outward from the body portion  212   a  of the first metal plate  212 . In addition, the protrusion  214   a  may be shaped to form the fixing groove  214  perforated so that an external input/output terminal is inserted therein. 
     Thus, according to this configuration of the present disclosure, if the protrusion  214   a  is formed such that the external input/output terminal is coupled to the second metal plate  214  rather than the first metal plate  212 , the power may be transmitted to an external electronic device through the first metal plate  212  with a higher electric conductivity, thereby minimizing the loss of power supplied from the battery module  200 . In addition, since the second metal plate  214  has more excellent heat dissipation characteristics than the first metal plate  212 , the second metal plate  214  is more advantageous in dissipating the heat generated in the external input/output terminal to the outside. 
     Meanwhile, even though the terms indicating directions such as upper, lower, left, right, front and rear directions are used in the specification, it is obvious to those skilled in the art that these merely represent relative positions for convenience in explanation and may vary based on a position of an observer or an object. 
     The present disclosure has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the scope of the disclosure will become apparent to those skilled in the art from this detailed description. 
     REFERENCE SIGNS 
       
     
       
         
           
               
               
             
               
                   
               
             
            
               
                 200: battery module 
                 210: module bus bar 
               
               
                 100: cylindrical battery cell 
                 220: module housing 
               
            
           
           
               
            
               
                 220s1, 220s2: accommodation portion 
               
            
           
           
               
               
            
               
                 111, 112: electrode terminal 
                 212: first metal plate 
               
               
                 214: second metal plate 
                 216: third metal plate 
               
               
                 220a, 220b: upper case, lower case 
                 212a, 212b: body portion, connection portion 
               
               
                 212p, 212h: coupling protrusion, coupling groove 
                 212i: insert portion 
               
               
                 212w: support wall 
                 214h: accommodation groove 
               
            
           
           
               
            
               
                 216a, 216b: bonding portion, connection extension 
               
               
                 214a, 214b: protrusion, fixing groove 
               
            
           
           
               
               
            
               
                 222: mounting portion 
                 222k: hook structure 
               
               
                   
               
            
           
         
       
     
     INDUSTRIAL APPLICABILITY 
     The present disclosure relates to a battery module including a module bus bar. In addition, the present disclosure may be used in industries related to a battery pack and a device equipped with the battery module.