Abstract:
A battery pack including a frame integrated with a reinforcement member and a supporting member, thereby realizing a compact and lightweight dimension. The battery pack includes a plurality of battery cells stacked on top of each other, a frame including a supporting member covering the plurality of battery cells and a reinforcement member formed inside the supporting member, and an end plate disposed at the exterior of the plurality of battery cells and coupled to the frame.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims priority to and the benefit of Korean Patent Application No. 10-2010-0051137, filed on May 31, 2010, the entire content of which is incorporated herein by reference. 
       BACKGROUND  
       [0002]    1. Field 
         [0003]    The present invention relates to a battery pack. 
         [0004]    2. Description of the Related Art 
         [0005]    In general, secondary batteries are capable of being charged and discharged and can be repeatedly used. Low-capacity secondary batteries, each including a single unit cell, are widely used in small portable electronic devices, such as mobile phones, notebook type computers, cameras, camcorders, and the like. On the other hand, large-capacity secondary batteries, each including multiple battery cells, may be used as motor driving power sources, such as a hybrid electric vehicle (HEV), an electric vehicle (EV), an electric scooter, or the like. 
         [0006]    A battery pack includes various components including a plurality of battery cells, fixing members, a case, and so on. However, these components may impede attainment of compact and lightweight battery packs. 
       SUMMARY  
       [0007]    According to one or more embodiments of the present invention, a battery pack includes a frame integrated with a reinforcement member and a supporting member, thereby providing a compact and lightweight dimension of the battery pack. 
         [0008]    One embodiment of the present invention provides a battery pack including a plurality of battery cells stacked together; a frame comprising a supporting member covering the battery cells and a reinforcement member within the supporting member; and an end plate on the battery cells and coupled to the frame. 
         [0009]    In one embodiment, the supporting member and the reinforcement member are made from different materials and are insert molded to each other. For example, the supporting member may be made from an insulating resin and the reinforcement member may be made from a metallic material. Further, a portion of the reinforcement member may protrude from the supporting member and extend through the end plate. 
         [0010]    In one embodiment, the supporting member includes a bottom portion covering one side of each of the plurality of battery cells; and a sidewall portion bent and extending from at least two sides of the bottom portion and covering two sides of each of the battery cells. The reinforcement member may be located in the sidewall portion and may include a base portion comprising a bar and extending in a direction generally parallel to a direction in which the battery cells are stacked; an extending portion extending from the base portion and protruding from the supporting member and passing through the end plate; and a screw thread on the extending portion. 
         [0011]    In one embodiment, the reinforcement member includes a plurality of coupling grooves and wherein the plurality of coupling grooves contain the supporting member. In another embodiment, the reinforcement member includes a plurality of coupling protrusions protruding from an outer surface of the reinforcement member. Further, the end plate may include a plate portion facing the plurality of battery cells and having an opening, wherein the reinforcement member extends through the opening; and a bent portion bent from and extending from two sides of the plate portion. 
         [0012]    As described above, the battery pack according to the embodiments of the present invention includes a frame having a reinforcement member and a supporting member coupled to each other by, for example, insert molding, thereby simplifying the manufacturing process and minimizing a size of the battery pack. 
         [0013]    In addition, the battery pack according to the embodiments of the present invention includes a reinforcement member and a supporting member made of different materials, thereby dispersing stress applied due to an external force. 
         [0014]    Further, the battery pack according to the embodiments of the present invention includes a reinforcement member made of a metallic material and a supporting member made of an insulating resin, thereby increasing mechanical strength, maintaining the shape and minimizing size while improving a heat dissipation capability and an insulating capability. 
         [0015]    Additional aspects of the invention will be set forth in part in the description that follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0016]    The objects, features and advantages of the present invention will be more apparent from the following detailed description in conjunction with the accompanying drawings, in which: 
           [0017]      FIG. 1  is a perspective view of a battery pack according to an embodiment of the present invention; 
           [0018]      FIG. 2  is an exploded perspective view of the battery pack shown in  FIG. 1 ; 
           [0019]      FIG. 3  is a cross-sectional view taken along the line A-A′ of  FIG. 2 ; 
           [0020]      FIG. 4  is a cross-sectional view illustrating a part of a battery pack corresponding to  FIG. 3 , according to another embodiment of the present invention; 
           [0021]      FIG. 5  is a cross-sectional view illustrating a part of a battery pack corresponding to  FIG. 3 , according to still another embodiment of the present invention; 
           [0022]      FIG. 6  is a cross-sectional view illustrating a part of a battery pack corresponding to  FIG. 3 , according to still another embodiment of the present invention; 
           [0023]      FIG. 7  is a plan view illustrating a reinforcement member shown in  FIG. 6 ; and 
           [0024]      FIG. 8  is a cross-sectional view illustrating a part of a battery pack corresponding to  FIG. 3 , according to still another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION  
       [0025]    Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
         [0026]      FIG. 1  is a perspective view of a battery pack according to an embodiment of the present invention,  FIG. 2  is an exploded perspective view of the battery pack shown in  FIG. 1 , and  FIG. 3  is a cross-sectional view taken along the line A-A′ of  FIG. 2 . 
         [0027]    Referring to  FIGS. 1 and 2 , the battery pack  100  according to an embodiment of the present invention includes a plurality of battery cells  110 , a frame  120  and an end plate  130 . 
         [0028]    The plurality of battery cells  110  may be stacked together, and are connected to each other in series or parallel by an electrical connection member. The plurality of battery cells  110  are configured to be connected or coupled to external electronic devices and to perform discharge operations for supplying power to the external electronic devices or charge operations for receiving power from the external electronic devices. 
         [0029]    Each of the plurality of battery cells  110  includes an electrode assembly  111  having a positive electrode plate and a negative electrode plate with a separator located therebetween, a case  112  providing for a space in which the electrode assembly  111  is housed, a cap assembly  113  coupled to the case  112  to hermetically sealing the case  112 , and a positive electrode terminal  114  and a negative electrode terminal  115  electrically connected to the positive electrode plate and the negative electrode plate, respectively, and protruding from the cap assembly  113 . Here, an insulator  101  having a relatively small thickness may be located between two adjacent battery cells  110  to prevent an unnecessary short-circuit. In addition, a thin insulator  101  may be attached to an outer surface of the outermost batter cell of the plurality of battery cells  110 . In the following description of the current embodiment, a direction in which the positive electrode terminal  114  and the negative electrode terminal  115  are exposed from the battery cell  110  is referred to as an upper direction. 
         [0030]    The frame  120  is formed to cover the plurality of battery cells  110 , and to fix the plurality of battery cells  110  and protect the same from external impact. The frame  120  includes a supporting member  121  and a reinforcement member  123  coupled to each other by, for example, insert molding. Here, the insert molding is a technique of combining components made of two different materials into one body. 
         [0031]    The supporting member  121  forms the external appearance of the frame  120 . Specifically, the supporting member  121  includes a bottom portion  121   a  covering the bottom portion of the plurality of battery cells  110 , and a sidewall portion  121   b  bent and extending from both sides of the bottom portion  121   a  to cover both sides of the plurality of battery cells  110 . The supporting member  121  serves to support the shape of the frame  120 . To this end, the supporting member  121  may be made of an insulating resin that is substantially indeformable. 
         [0032]    The reinforcement member  123  is formed within the supporting member  121  and serves to reinforce the strength of the frame  120 . To this end, the reinforcement member  123  may be made of a metal having high strength, for example, stainless steel. Here, the reinforcement member  123  may be at least one restraint rod positioned at the sidewall portion  121   b  of the supporting member  121 . A portion of the reinforcement member  123  is exposed from the supporting member  121  to then pass through the end plate  130 . 
         [0033]    In detail, as shown in  FIG. 3 , the reinforcement member  123  includes a base portion  124 , an extending portion  125 , and a screw thread  126 .  FIG. 3  shows a portion of the sidewall portion  121   b  of the supporting member  121 , in which the reinforcement member  123  is positioned. The base portion  124  is a bar extends in a direction substantially parallel to a direction in which the plurality of battery cells  110  are stacked. The extending portion  125  extends from the base portion  124  so as to be exposed from the supporting member  121  and passes through the end plate  130 . The screw thread  126  is formed on the outer surface of the extending portion  125  and allows the nut  135  to be fastened with the extending portion  125 . 
         [0034]    As described above, the frame  120  is formed such that the supporting member  121  and the reinforcement member  123  are coupled to each other by, for example, insert molding, thereby simplifying the manufacturing process of the battery pack  100  and achieving a compact dimension of the battery pack  100 . In addition, since the supporting member  121  and the reinforcement member  123  of the frame  120  are formed using different materials, the stress applied to the battery pack  100  can be dispersed. Further, since the reinforcement member  123  is made of a metallic material and the supporting member  121  is made of an insulating resin, the frame  120  may improve the heat dissipation capability and the insulating capability of the battery pack  100 . Further, compared to a frame made of only a resin, the frame  120  of the embodiments of the present invention may have increased mechanical strength and is capable of maintaining the shape of the battery pack  100  while minimizing a weight of the battery pack  100 , unlike a frame made of only a metal. 
         [0035]    With reference again to  FIG. 2 , the end plate  130  is formed to cover exterior sides of the plurality of battery cells  110 , specifically, both sides that are not covered by the frame  120 , and is coupled to the frame  120  to then be fixed. The end plate  130  fixes the plurality of battery cells  110  together with the frame  120 . The end plate  130  may be made of a metal or a resin, and may include a plate portion  131 , a bent portion  132 , and a throughhole or opening  133 . 
         [0036]    The plate portion  131  faces and covers the battery cell  110  and is coupled to the frame  120 . 
         [0037]    The bent portion  132  is bent and extends from both edges of the plate portion  131 . The bent portion  132  reinforces the mechanical strength of the end plate  130 , thereby preventing the end plate  130  from being significantly bent due to an external force. 
         [0038]    The throughhole  133  is formed at a region of the plate portion  131  generally corresponding to the extending portion  125  of the reinforcement member  123 , and the extending portion  125  of the reinforcement member  123  is inserted into the throughhole  133 . 
         [0039]    The end plate  130  is fixedly coupled to the frame  120  such that the extending portion  125  of the reinforcement member  123  is inserted into the throughhole  133  of the end plate  130  and the nut  135  is fastened with the extending portion  125  through the screw thread  126  of the reinforcement member  123 . 
         [0040]    As described above, the battery pack  100  according to the embodiment of the present invention includes the frame  120  having the supporting member  121  and the reinforcement member  123  coupled to each other by, for example, insert molding, thereby simplifying the manufacturing process thereof while minimizing a size of the battery pack. 
         [0041]    In addition, in the battery pack  100  according to the embodiment of the present invention, since the supporting member  121  and the reinforcement member  123  are formed using different materials, the stress applied due to an external force can be dispersed. 
         [0042]    Further, in the battery pack  100  according to the embodiment of the present invention, because the supporting member  121  is made of an insulating resin and the reinforcement member  123  is made of a metallic material, the heat dissipation capability and the insulating capability of the battery pack  100  can be improved, and shape maintaining capability and minimized weight of the battery pack  100  can also be achieved while increasing mechanical strength of the battery pack  100 . 
         [0043]    A battery pack corresponding to  FIG. 4 , according to another embodiment of the present invention will now be described. 
         [0044]      FIG. 4  is a cross-sectional view illustrating a part of a battery pack generally corresponding to  FIG. 3 , according to another embodiment of the present invention. 
         [0045]    The battery pack according to this embodiment is substantially the same as the battery pack  100  according to the previous embodiment in view of configuration and function, except for the shape of a reinforcement member  223  of a frame  220 , and therefore a description of the similar components will be omitted. In the following, the battery pack according to this embodiment will be described with regard to the reinforcement member  223  of the frame  220 . 
         [0046]    Referring to  FIG. 4 , the frame  220  is formed by coupling a supporting member  121  and the reinforcement member  223  to each other by, for example, insert molding. 
         [0047]    The reinforcement member  223  is substantially the same as the reinforcement member  123  shown in  FIG. 3 , except that it further includes a plurality of coupling grooves  227  formed on the outer surface of a base portion  124 . The plurality of coupling grooves  227  allow the supporting member  121  to be filled to be securely fixed. 
         [0048]    As described above, the battery pack according to the embodiment further includes the plurality of coupling grooves  227  formed in the reinforcement member  223 , thereby increasing coupling strength between the reinforcement member  223  and the supporting member  121  made of different materials. 
         [0049]    A battery pack according to still another embodiment of the present invention will now be described. 
         [0050]      FIG. 5  is a cross-sectional view illustrating a part of a battery pack according to still another embodiment of the present invention, the part corresponding to  FIG. 3 . 
         [0051]    The battery pack according to this embodiment is substantially the same with the battery pack  100  according to the previous embodiment in view of configuration and function, except for the shape of a reinforcement member  323  of a frame  320 , and a description of the similar components will be omitted. In the following, the battery pack according to this embodiment will be described with regard to the reinforcement member  323  of the frame  320 . 
         [0052]    Referring to  FIG. 5 , the frame  320  is formed by coupling a supporting member  121  and the reinforcement member  323  to each other by, for example, insert molding. 
         [0053]    The reinforcement member  323  is substantially the same as the reinforcement member  123  shown in  FIG. 3 , except that it further includes a plurality of coupling protrusions  327  formed on the outer surface of a base portion  124 . The plurality of coupling protrusions  327  serve as supporters resisting against external forces while increasing coupling strength between the reinforcement member  323  and the supporting member  121  made of different materials. 
         [0054]    As described above, the battery pack according to the embodiment further includes the plurality of coupling protrusions  327  formed in the reinforcement member  323 , thereby further increasing coupling strength between the reinforcement member  323  and the supporting member  121  made of different materials and increasing resistance against external forces. 
         [0055]    Next, a battery pack according to still another embodiment of the present invention will be described. 
         [0056]      FIG. 6  is a cross-sectional view illustrating a part of a battery pack according to still another embodiment of the present invention, the part corresponding to  FIG. 3 , and  FIG. 7  is a plan view illustrating a reinforcement member shown in  FIG. 6 . 
         [0057]    The battery pack according to this embodiment is substantially the same with the battery pack  100  according to the previous embodiment in view of configuration and function, except for the shape of a reinforcement member  423  of a frame  420 , and a description of the similar components will be omitted. In the following, the battery pack according to this embodiment will be described with regard to the reinforcement member  423  of the frame  420 , and a connection member  426 . 
         [0058]    Referring to  FIGS. 6 and 7 , the frame  420  is formed by coupling a supporting member  121 , the reinforcement member  423  and the connection member  426  by, for example, insert molding. 
         [0059]    The reinforcement member  423  is formed within the supporting member  121  and reinforces mechanical strength of the frame  420 . To this end, the reinforcement member  423  may be made of a metal having high strength, for example, stainless steel. Here, the reinforcement member  423  may be formed in a mesh type. Specifically, the reinforcement member  423  includes a first metal line  424  and a second metal line  425 . The reinforcement member  423  is formed throughout a sidewall portion of the supporting member  121 , thereby further increasing mechanical strength of the frame  420 . 
         [0060]    The connection member  426  may be formed at a region corresponding to the throughhole  133  of the end plate ( 130  of  FIG. 2 ) in the frame  420 , and may be a bolt. The connection member  426  includes a base portion  427  formed outside the reinforcement member  423  within the supporting member  121 , an extending portion  428  exposed to one side of the supporting member  121 , and a screw thread  429  formed on the outer surface of the extending portion  428 . The extending portion  428  of the connection member  426  is inserted into the throughhole  133  of the end plate  130  and a nut ( 135  of  FIG. 2 ) is fastened with the extending portion  428  through the screw thread  429 , thereby allowing the end plate  130  to be fixedly coupled to the frame  420 . 
         [0061]    As described above, the battery pack according to the embodiment includes the mesh-type reinforcement member  423  throughout the sidewall portion of the supporting member  121 , thereby further increasing the mechanical strength of the frame  420  and ultimately further increasing resistance against external forces. 
         [0062]    A battery pack according to still another embodiment of the present invention will now be described. 
         [0063]      FIG. 8  is a cross-sectional view illustrating a part of a battery pack according to still another embodiment of the present invention, the part generally corresponding to  FIG. 3 . 
         [0064]    The battery pack according to this embodiment is substantially the same as the battery pack  100  according to the previous embodiment in view of configuration and function, except that the shape of a reinforcement member  423  of a frame  520 , and a connection member  523  and a bolt  535  are further provided. As such, a description of the similar components will be omitted. In the following, the battery pack according to this embodiment will be described with regard to the reinforcement member  423  of the frame  520 , the connection member  523  and the bolt  535 . 
         [0065]    Referring to  FIG. 8 , the frame  520  is formed by coupling a supporting member  121 , the reinforcement member  423  and the connection member  523  to each other by, for example, insert molding. 
         [0066]    Since the reinforcement member  423  is substantially the same as previously described with reference to  FIG. 6 , it will not be described again. 
         [0067]    The connection member  523  may be formed at a region corresponding to the throughhole  133  of the end plate ( 130  of  FIG. 2 ) in the frame  520 , and may be a nut. The connection member  523  is formed outside the reinforcement member  423  within the supporting member  121  so as to be exposed from one side of the supporting member  121 . 
         [0068]    The bolt  535  includes a screw thread  536  formed on a portion of its outer surface, and passes through the throughhole  133  of the end plate ( 130  of  FIG. 2 ) to then be fastened with the connection member  523 , thereby allowing the frame  520  to be fixedly coupled to the end plate ( 130  of  FIG. 2 ). Since the bolt  535  is used in coupling the frame  520  and the end plate ( 130  of  FIG. 2 ), the nut  135  of  FIG. 2  may be omitted. 
         [0069]    As described above, the battery pack according to the embodiment includes the mesh-type reinforcement member  423  throughout the sidewall portion of the supporting member  121 , thereby further increasing the mechanical strength of the frame  520  and ultimately further increasing resistance against external forces. 
         [0070]    Although the battery pack according to the present invention has been illustrated through particular embodiments, it should be understood that many variations and modifications may be made in those embodiments within the scope of the present invention.