Patent Publication Number: US-2023143556-A1

Title: Battery Module And Battery Pack Including The Same

Description:
TECHNICAL FIELD 
     Cross Citation with Related Application(s) 
     This application claims the benefit of Korean Patent Application No. 10-2019-0127010 filed on Oct. 14, 2020 with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
     The present disclosure relates to a battery module and a battery pack including the same, and more particularly, to a battery pack including a battery module electrically connected through a terminal connection structure. 
     BACKGROUND ART 
     Since secondary batteries are easily applicable to various product groups and has electrical characteristics such as high energy density, they are universally applied not only for a portable device but also for an electric vehicle or a hybrid electric vehicle, an energy storage system or the like, which is driven by an electric driving source. Such secondary battery is attracting attention as a new environment-friendly energy source for improving energy efficiency since it gives a primary advantage of remarkably reducing the use of fossil fuels and also does not generate by-products from the use of energy at all. 
     A battery pack applied to an electric vehicle and the like has a structure in which a plurality of cell assemblies including a plurality of unit cells are connected in series to obtain high output. And, the unit cell can be repeatedly charged and discharged by an electrochemical reaction between components, including a positive electrode current collector, a negative electrode current collector, a separator, an active material, an electrolyte and the like. 
     Meanwhile, recently, along with a continuous rise of the necessity for a large-capacity secondary battery structure, including the utilization of the secondary battery as an energy storage source, there is a growing demand for a battery pack of a multi-module structure which is an assembly of battery modules in which a plurality of secondary batteries are connected in series or in parallel. 
     When a plurality of battery cells are connected in series/parallel to configure a battery pack, a method of configuring a battery module composed of at least one battery cell and then adding other components to at least one battery module to configure a battery pack is common. The number of battery modules included in the battery pack or the number of battery cells included in the battery module may be variously set according to the required output voltage or charge/discharge capacity. 
     In order to connect a plurality of battery modules to each other, a terminal connection structure may be fastened between battery modules adjacent to each other, and in this case, the bolt and nut fastening structure can be applied. However, it is necessary to control a precise position in order to assemble the bolt to the nut that is completely fixed to the battery module. Consequently, the relative assembling property of the bolts can be reduced and the defective rate can be increased. In addition, additional processes such as bonding and welding are required in order to bind the nut to the battery module, resulting in an increase in the price of parts. In order to solve these problems, an unfixed nut was sometimes used, but in this case, problems such as detachment of the nut may also occur. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problem 
     It is an object of the present disclosure to provide a battery module in which a structure in which the nut can flow is created in the terminal connection structure between battery modules, thereby improving the assembling property of the bolt and nut and at the same time preventing the detachment of nut. 
     It is another object of the present disclosure to provide a battery pack configured such that a plurality of battery modules having such a nut structure is fastened to each other with a terminal connection structure. 
     However, the technical problem to be solved by embodiments of the present disclosure is not limited to the above-described problems, and can be variously expanded within the scope of the technical idea included in the present disclosure. 
     Technical Solution 
     According to one embodiment of the present disclosure, there is provided a battery module comprising: a cell assembly including at least one battery cell; a bus bar assembly including a terminal bus bar electrically connected to the electrode lead of the cell assembly, and a bus bar frame for covering the cell assembly on at least one side; and an insulating frame for covering the bus bar assembly from the outside, wherein the battery module comprises a nut adjacent to the terminal bus bar and mounted in a nut insertion chamber having a space inside the insulating frame, and the insulating frame comprises a protrusion that protrudes from a side wall of the nut insertion chamber and makes contact with the nut. 
     The nut has a size that can move in right and left directions in the nut insertion chamber, and when the nut moves, the protrusion may be configured to spread in the outside direction of the nut insertion chamber. 
     The nut has a jaw portion at the lower portion that protrudes toward the side wall of the nut insertion chamber from the main body of the nut, and the jaw portion may interfere with the protrusion and limit the vertical movement of the nut. 
     A fastening hole is formed in the terminal bus bar, and the nut may be mounted in the nut insertion chamber so that the screw hole at least partially overlaps the fastening hole. 
     The protrusion may include an inclined surface connected to the side wall at an upper portion. 
     The nut insertion chamber and the protrusion may be formed together during an injection process of the insulating frame. 
     The protrusion may be formed on a side wall adjacent to the bus bar in the nut insertion chamber. 
     The protrusion may be formed in a branch portion that protrudes from the upper portion of the side wall to the side surface and extends downward. 
     According to another embodiment of the present disclosure, there is provided a battery pack comprising the plurality of battery modules, and a bolt that passes through the fastening hole of the terminal bus bar to be screw-coupled to the screw hole of the nut. 
     The battery pack includes a terminal connection structure having an inter-module bus bar that connects the terminal bus bars of the adjacent battery modules, wherein the bolt may pass through the inter-module bus bar to be coupled to the nut. 
     The bolt may pass through the screw hole of the nut to be fixed to the insulating frame. 
     According to yet another embodiment of the present disclosure, there is provided a device comprising the at least one battery pack. 
     Advantageous Effects 
     According to embodiments, the nut is mounted on the outer terminal connection part of the battery module to secure a movable space, so that not only it is possible to improve the ease of fastening with the bolt for connection with adjacent battery modules, but also it is possible to improve the assembly speed because control of the precise position of bolt and nuts is not required, and further the defective rate due to assembly errors can be reduced. 
     Furthermore, even if the nut moves for the ease of assembly, the movement in up and down directions is restricted, thereby preventing occurrence of problems such as detachment of the nut. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view showing a battery module according to one embodiment of the present disclosure; 
         FIG.  2    is an exploded perspective view showing a bus bar assembly, an insulating frame, and an end plate of a battery module according to one embodiment of the present disclosure; 
         FIG.  3    is a cross-sectional view taken along the line III-III of  FIG.  1   ; 
         FIG.  4    is a diagram showing a state before the nut is arranged in the nut mounting chamber of the insulating frame of the battery module according to one embodiment of the present disclosure; 
         FIG.  5    is a diagram showing a state in which a nut is arranged in a nut mounting chamber of an insulating frame of a battery module according to one embodiment of the present disclosure; 
         FIG.  6    is a perspective view showing a state in which a terminal connection structure is fastened to a battery module according to one embodiment of the present disclosure; 
         FIG.  7    is a cross-sectional view taken along the line VII-VII of  FIG.  6   ; and 
         FIG.  8    is a schematic diagram showing a process of assembling a terminal connection structure to a battery module according to one embodiment of the present disclosure, and the relative positions of the bolt in the assembled state, the fastening hole of the terminal bus bar, the screw hole of the nut, and the fastening hole of the inter-module bus bar. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out them. The present disclosure may be modified in various different ways, and is not limited to the embodiments set forth herein. 
     Further, throughout the specification, when a portion is referred to as “including” a certain component, it means that the portion can further include other components, without excluding the other components, unless otherwise stated. 
       FIG.  1    is a perspective view showing a battery module according to one embodiment of the present disclosure.  FIG.  2    is an exploded perspective view showing a bus bar assembly, an insulating frame, and an end plate of a battery module according to one embodiment of the present disclosure. 
     Referring to  FIGS.  1  and  2   , the battery module  10  according to embodiments of the present disclosure includes a cell assembly, a bus bar assembly  150  on at least one side of a module case  135  that houses this cell assembly and forms the exterior of the battery module  100 , and an insulating frame  163 . The bus bar assembly  150  may be configured such that the bus bar  151  is fixed outwardly to the bus bar frame  155  located on the side surface of the direction in which the electrode lead of the cell assembly is drawn out. The electrode lead of the cell assembly can pass through a slit formed in the bus bar frame  155  to be electrically connected to the bus bar  151 . The insulating frame  163  is arranged outside the bus bar assembly  150 . The insulating frame  163  is arranged adjacent to the bus bar assembly  150 , and the end plate  165  covers the insulating frame  163  and is located on the outside thereof. 
     Each of the insulating frame  163  and the bus bar frame  155  may be made of a non-conductive injection molding material, and the end plate  165  may be made of a metallic material. 
     The battery cells constituting the cell assembly may be provided as pouch-type secondary batteries, and may be provided by stacking a plurality of cells in the cell assembly. The plurality of battery cells may be electrically connected to each other, and each of the battery cells protrudes from the electrode assembly, a battery case for housing the same, and an electrode lead that protrudes outward from the battery case and is electrically connected to the electrode assembly. 
     In addition, the battery module  100  may include various electronic components, and for example, it may include an ICB (Internal Circuit Board), a BMS (Battery Management System), and the like. Electrical components such as the ICB and the BMS board can be electrically connected to the plurality of battery cells. 
     The battery module  100  can form a module terminal portion that plural numbers are electrically coupled adjacent to each other. In this embodiment, the battery module  100  may include terminal bus bars  153  located at the outermost side of the bus bars fixed to the bus bar frame  155 . The terminal bus bar  153  may include a plate that is bent perpendicularly to the main surface of the bus bar frame  155  at the upper end, so that a fastening hole may be formed in the plate. 
       FIG.  3    is a cross-sectional view taken along the line III-III of  FIG.  1   .  FIG.  4    is a diagram showing a state before the nut is arranged in the nut mounting chamber of the insulating frame of the battery module according to one embodiment of the present disclosure.  FIG.  5    is a diagram showing a state in which a nut is arranged in a nut mounting chamber of an insulating frame of a battery module according to one embodiment of the present disclosure. 
     A nut insertion chamber  168  can be provided adjacent to the terminal bus bar  153  within the insulating frame  163 . A space is provided in the nut insertion chamber  168  so that the nut  173  can be mounted, and the nut  173  is mounted in the nut insertion chamber  168 . In this embodiment, the insulating frame  163  includes a protrusion  1681  that protrudes from the side wall  1682  of the nut insertion chamber  168  and makes contact with the nut  173 . The nut insertion chamber  168  has a substantially rectangular flat cross-section, and the width of the nut  173  in the first direction may be formed smaller than the width of the nut insertion chamber  168  in the first direction. Here, the first direction can be defined as a direction parallel to the long side of the insulating frame  163 . Also, the width of the nut  173  in the second direction may be formed to be the same as the width of the nut insertion chamber  168  in the second direction. Here, the width of the nut insertion chamber  168  in the second direction means the width between the most protruding portion of the protrusion  1681  and the opposite side wall. Therefore, basically, when the nut  173  is mounted in the nut insertion chamber  168 , it does not move to an extent sufficient to separate from the nut insertion chamber  168  because it makes contact with the protrusion  1681 . 
     Further, in the case of the protrusion  1681 , which is a configuration of the insulating frame  163  formed of an injection-molded material, a gap can be widen outward when force is applied by the movement of the nut  173 , thereby providing a sufficient space for the nut  173  to move in the left and right directions. Therefore, when the bolt is inserted into the insertion hole of the nut  173 , the degree of freedom of the nut  173  can be increased by allowing it to move in the left and right directions. 
     As shown in  FIG.  4   , the protrusion  1681  may be formed at an end of the branch portion  1683  that protrudes to the side surface from the upper portion of the side wall  1682  and extends downward. The branch portion  1683  may be spaced apart from the side wall  1682  at a distance, and may have a configuration in which only the upper portion is connected to the side wall  1682 . With such a configuration, the margin that the protrusion  1681  located at the end of the branch portion  1683  can form a gap to the outside becomes larger, so that the degree of freedom of the nut  173  can be further increased. 
     An inclined surface extending from the side wall  1682  toward the nut  173  may be formed on the upper portion of the protrusion  1681 . That is, when the nut  173  is inserted from the upper portion, it can be more easily mounted in the nut insertion chamber  168  along the inclined surface. 
     Meanwhile, the lower portion of the nut  173  has a jaw portion  1731  protruding from the body of the nut  173  toward the side wall  1682  of the nut insertion chamber  168 , and the jaw portion  1731  interferes with the protrusion  1681  to prevent the nut  173  from moving up and down. Thereby, while the nut  173  can move to the left and right while pushing out the protrusion  1681  at the time of assembly, and at the same time, the vertical flow of the nut  173  is prevented by the coupling of the protrusion  1681  and the jaw portion  1731 , so that even before assembling, it is possible to prevent the nut  173  from being detached during a procedure such as a process. 
     A terminal bus bar  153  may be arranged above the nut insertion chamber  168  on which the nut  173  is mounted. This is positioned when the bus bar assembly  150  to which the terminal bus bar  153  is fixed and the insulating frame  163  provided with the nut insertion chamber  168  are coupled to each other. A fastening hole is formed in the terminal bus bar  153 , and when a bolt passes through the terminal bus bar  153  to be fastened to the nut  173 , it can be fastened through the fastening hole. And, the nut  173  is mounted in the nut insertion chamber  168  so that the screw hole overlaps at least partially with the fastening hole. This makes it possible to improve the ease of fastening when inserting the bolt into the nut  173  for electrical connection between the battery modules, and increase the working speed. This will be described below using a schematic diagram. 
     The nut insertion chamber  168  and the nut  173  inserted therein may be arranged on both sides of the insulating frame  163  in the plane direction, that is, one-by-one on both sides in the first direction. Terminal connection structures are respectively fastened to the nuts  173  arranged on both sides through bolts, and can used for electrical connection with battery modules adjacent to both sides. 
       FIG.  6    is a perspective view showing a state in which a terminal connection structure is fastened to a battery module according to one embodiment of the present disclosure, and  FIG.  7    is a cross-sectional view taken along the line VII-VII of  FIG.  6   . 
     Referring to  FIG.  6   , the terminal connection structure  180  can be fastened to the module terminal portion in order to fasten the adjacent battery module  100 . The terminal connection structure  180  can be fixed to the end plate  165 . The module terminal portion may include a terminal bus bar  153  and a nut  173  mounted in the nut insertion chamber  168 . The end plate  165  exposes the terminal bus bar  153  fixed to the bus bar assembly  150  while being coupled to the insulating frame  163  and the bus bar assembly  150 , the coupling with the adjacent battery module can be achieved while the terminal connection structure  180  fixed to the end plate  165  is coupled to the terminal bus bar  153 . 
     Referring to  FIG.  7   , the terminal connection structure  180  may include an inter-module bus bar  185  that provides electrical connection between adjacent battery modules, and a bolt  183  for coupling the inter-module bus bar  185  with the terminal bus bar  153  of each battery module  100 . That is, the bolt  183  may pass through the inter-module bus bar  185  and the terminal bus bar  153  to be screw-coupled to the screw hole of the nut  173 . At this time, the bolt  183  may pass through the fastening hole of the inter-module bus bar  185  and the fastening hole of the terminal bus bar  153 , respectively, and can be coupled to the nut  173  mounted in the nut insertion chamber  168 . In addition, the bolt  183  can be fixed to the insulating frame  163  through the screw hole of the nut  173 . 
       FIG.  8    is a schematic diagram showing a process of assembling a terminal connection structure to a battery module according to one embodiment of the present disclosure, and the relative positions of the bolt, the fastening hole of the terminal bus bar, the screw hole of the nut, and the fastening hole of the inter-module bus bar in the assembled state. 
     If the relative positions of the screw holes of the nut  173 , and the fastening holes of the terminal bus bar  153  and the inter-module bus bar  185  are slightly misaligned before assembling, first, the fastening hole of the inter-module bus bar  185  is in a state of being not yet coupled and thus, is moved to the right and left to align with the hole of the terminal bus bar  153 . However, in the case of the screw hole of the nut  173 , if the nut  173  is fixed and the left and right movement does not occur at all, complementation is impossible. However, according to one embodiment of the present disclosure, when allowing the nut  173  to move by an external force, a gap of the protrusion  1681  is widened outward and the position can be moved to a prescribed position. That is, since the nut  173  can move while pushing the protrusion  1681  in the nut insertion chamber  168 , the nut  173  can move more or less along the insertion position of the bolt  183 . Therefore, precise control is not required to fasten the bolt  183  to the terminal bus bar  153  and the nut  173  for electrical connection of the adjacent battery module  100 . As the end of the bolt  183  is inserted into the fastening hole of the terminal bus bar  153  and the inter-module bus bar  185 , the nut  173  moves in the nut insertion chamber  168  so that the screw hole of the nut  173  is aligned with the end of the bolt  183 , and the bolt  183  and the nut  173  can be fastened without interference. That is, before assembling, the flow of the nut  173  is restricted to some extent by the protrusion  1681 , and when assembling, the degree of freedom of the nut  173  is increased by slightly pushing the protrusion  1681  to the outside, thereby absorbing the tolerance of the bolt  183  and the assembly tolerance, and thus ensure the fastening property of the bolt  183  and the nut  173 . 
     Meanwhile, one or more battery modules according to the embodiments of the present disclosure can be packaged in a pack case while being electrically connected to each other through a terminal connection structure, thereby forming a battery pack. That is, the plurality of battery modules can be electrically connected by fixing the inter-module busbars connecting the terminal busbars of the adjacent battery modules using bolts, thereby configuring a battery pack. 
     The above-mentioned battery pack and battery pack including the same can be applied to various devices. Such a device may be applied to a vehicle means such as an electric bicycle, an electric vehicle, or a hybrid vehicle, but the present disclosure is not limited thereto, and is applicable to various devices that can use a battery module, which also belongs to the scope of the present disclosure. 
     Although the invention has been shown and described with reference to the preferred embodiments, the scope of the present disclosure is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts of the present disclosure, which are defined in the appended claims, also belong to the scope of the present disclosure. 
     DESCRIPTION OF REFERENCE NUMERALS 
       
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 100: battery module 
                 135: module case 
               
               
                   
                 150: bus bar assembly 
                 151: bus bar 
               
               
                   
                 153: terminal busbar 
                 155: busbar frame 
               
               
                   
                 163: insulation frame 
                 165: end plate 
               
               
                   
                 168: nut insertion chamber 
                 173: nut 
               
               
                   
                 1681: protrusion 
                 180: terminal connection structure 
               
               
                   
                 183: bolt