Abstract:
A battery pack having a cover frame configured to be tightly coupled to the four side surfaces of a bare cell. The cover frame includes a rectangular cell receiving part framed by four frame parts, wherein each of the four frame parts include a support section for supporting the lower case of the bare cell, and three of the frame parts include ribs supporting the upper case of the bare cell, wherein a fourth one of the frame parts includes tab receiving grooves supporting the electrode tabs extending from the bare cell. The cover frame further includes a protection circuit module receiving part adjacent to, and separated from the cell receiving part by the fourth one of the frame parts.

Description:
CLAIM OF PRIORITY 
       [0001]    This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application earlier filed in the Korean Intellectual Property Office on the 10 Feb. 2011 and there duly assigned Serial No. 10-2011-0011869. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    Embodiments of the present invention relate to a battery pack. 
         [0004]    2. Description of the Related Art 
         [0005]    In general, a battery pack includes a bare cell having an electrode assembly housed in a case, and a cover frame surrounding edges of side surfaces of the bare cell. The cover frame is required to be tightly coupled to the side surfaces of the bare cell and easily formable to be manufactured in high yield. 
       SUMMARY OF THE INVENTION 
       [0006]    Embodiments of the present invention provide a battery pack having a cover frame configured to be tightly coupled to side surfaces of a bare cell and easily formable to be manufactured in high yield. 
         [0007]    According to an embodiment of the present invention, a battery pack is provided, including a bare cell, and a cover frame formed to surround top, bottom and opposing side surfaces of the bare cell, wherein the cover frame includes a rib formed only at lengthwise portions corresponding to opposing short side surfaces of the bare cell, and the rib protrude inwardly with respect to the cover frame. 
         [0008]    The rib may be formed at one end of the cover frame in a thickness direction, and a support portion may be formed at the other end of the cover frame in the thickness direction to protrude inwardly with respect to the cover frame. 
         [0009]    The support portion may be formed at a region other than a region where the rib is formed. 
         [0010]    The rib may cover a portion of a top surface of the bare cell, and the support portion may cover a portion of a bottom surface of the bare cell. 
         [0011]    The cover frame may include a first frame surrounding the top surface of the bare cell, a second frame surrounding the bottom surface of the bare cell and formed to face the first frame, and third and fourth frames surrounding short side surfaces of the bare cell and connecting one and the other ends of the first and second frames, respectively. 
         [0012]    The ribs may be formed in the third frame and the fourth frame and may be located at the distance from the first frame and the second frame. 
         [0013]    The battery pack may further include a rib formed in the second frame. 
         [0014]    The rib formed in the second frame may be located at the same distance from the one and the other ends of the second frame. 
         [0015]    One and the other ends of the support portion formed in the second frame may be connected to one ends of the support portions formed in the third and fourth frames, respectively. 
         [0016]    The ribs may be formed in the third frame and the fourth frame and may be located to be opposite to each other in view of the location of the distance from the first frame and the second frame. 
         [0017]    The battery pack may further include a rib formed in the second frame. 
         [0018]    The rib formed in the second frame may be located at the same distance from the one and the other ends of the second frame. 
         [0019]    One and the other ends of the support portion formed in the second frame may be connected to one ends of the support portions formed in the third and fourth frames, respectively. 
         [0020]    The cover frame may be made of an elastic material. 
         [0021]    In the battery pack according to the present invention, the cover frame can be easily formed, thereby reducing the molding cost and improving the yield. 
         [0022]    Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    A more complete appreciation of the invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which like reference symbols indicate the same or similar components, wherein: 
           [0024]      FIG. 1  is a perspective view of a completed battery pack according to an embodiment of the present invention; 
           [0025]      FIG. 2  is an exploded perspective view of a polymer cell in the battery pack shown in  FIG. 1 ; 
           [0026]      FIG. 3A  is a perspective view of a cover frame in the battery pack shown in  FIG. 1 , and  FIG. 3B  is a plan view of the cover frame shown in  FIG. 3A ; and 
           [0027]      FIG. 4A  is a perspective view of a cover frame in a battery pack according to another embodiment of the present invention, and  FIGS. 4B and 4C  are alternative plan views of the cover frame shown in  FIG. 4A . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
         [0029]      FIG. 1  is a perspective view of a completed battery pack according to an embodiment of the present invention, and  FIG. 2  is an exploded perspective view of a polymer cell in the battery pack shown in  FIG. 1 . 
         [0030]    Referring to  FIG. 1 , the battery pack  100  according to the embodiment of the present invention includes a bare cell  10 , and a cover frame  20  surrounding top, bottom and opposing side surfaces of the bare cell  10 . 
         [0031]    Referring to  FIG. 2 , the bare cell  10  includes an electrode assembly  1  and a case  11  housing the electrode assembly  10 . The electrode assembly  1  includes a positive electrode plate  2  having a positive electrode active material coated on its both surfaces, a negative electrode plate  4  having a negative electrode active material coated on its both surfaces, and a separator  3  interposed between the positive electrode plate  2  and the negative electrode plate  4 . In addition, a positive electrode tab  5  protruding a predetermined length and functioning as a positive electrode is attached to the positive electrode plate  2 . Further, a negative electrode tab  6  protruding a predetermined length and functioning as a negative electrode is attached to the negative electrode plate  4 . An insulation tape  7  may further be provided in the positive electrode tab  5  and the negative electrode tab  6  to insulate each of the positive electrode tab  5  and the negative electrode tab  6  from the case  11 , respectively. The positive electrode tab  5  and the negative electrode tab  6  are drawn out to the outside through one side surface of the case  11  and are electrically connected to a protection circuit module (PCM) (not shown), respectively. 
         [0032]    The case  11  is folded at the center of a layer forming the case  11  to then be divided into a lower case  12  and an upper case  13 . The lower case  12  has a receiving section  12   a  formed by a pressing process to receive the electrode assembly  1 . The electrode assembly  1  is received in the receiving section  12   a  and the lower case  12  is covered by the upper case  13 , followed by thermally welding edges of the receiving section  12   a,  thereby completing the bare cell  10 . 
         [0033]    In the present invention, a surface of the bare cell  10  from which the electrode tabs  5  and  6  extend is referred to as a top surface, and a surface opposite to and facing the top surface is referred to as a bottom surface. In addition, a surface connecting one short side of the top surface to one short side of the bottom surface is referred to as a first short side surface, and a surface connecting the other short side of the top surface to the other short side of the bottom surface is referred to as a second short side surface. Further, a surface connecting one long side of the top surface to one long side of the bottom surface is referred to as a first long side surface, and a surface, formed by upper case  13 , connecting the other long side of the top surface to the other long side of the bottom surface is referred to as a second long side surface. 
         [0034]      FIG. 3A  is a perspective view of a cover frame in the battery pack shown in  FIG. 1 , and  FIG. 3B  is a plan view of the cover frame shown in  FIG. 3A . 
         [0035]    Referring to  FIGS. 3A and 3B , the cover frame  20  includes a first frame  21 , a second frame  22 , a third frame  23  and a fourth frame  24  surrounding the top surface (from which the electrode tabs  5  and  6  extend), bottom surface and opposing short side surfaces of the bare cell  10 . Thus, the bare cell  10  is received in a cell receiving section  20   a  surrounded by the first to fourth frames  21 ,  22 ,  23  and  24 . The cover frame  20  may further include a PCM (protection circuit module) receiving section  20   b  adjacent to and separated from the cell receiving section  20   a  by first frame  21 . In addition, the cover frame  20  may be made of an elastic material such as rubber. However, the present invention does not limit the material of the cover frame  20  to rubber, and any elastic material that is somewhat deformable can be used. 
         [0036]    The first frame  21  includes a first support portion  21   a  ( FIG. 3B ) formed at a thicknesswise bottom end (edge) and tab receiving grooves  21   b  ( FIG. 3A ) formed at a thicknesswise top end (edge). 
         [0037]    The first support portion  21   a  is formed along at least a lengthwise a portion of the first frame  21  and extends from the thicknesswise bottom end of the first frame  21  toward the inside of the cover frame  20 , that is, toward the cell receiving section  20   a.  Thus, the first support portion  21   a  supports the first long side surface of the bare cell  10  accommodated inside the cell receiving section  20   a  of the cover frame  20 . In addition, in order to increase the supporting capacity of the first support portion  21   a,  the first support portion  21   a  is preferably formed from a lengthwise end of the first frame  21  to the other lengthwise end of the first frame  21 . 
         [0038]    The tab receiving grooves  21   b  are formed at locations corresponding to the positive electrode tab  5  and the negative electrode tab  6  of the bare cell  10  accommodated in the cell receiving section  20   a.  Therefore, the positive electrode tab  5  and the negative electrode tab  6  are drawn out toward the PCM receiving section  20   b  through the tab receiving grooves  21   b,  respectively, for electrical connection to the PCM (not shown) accommodated in the 
         [0039]    PCM receiving section  20   b.    
         [0040]    The second frame  22  includes a second support portion  22   a  formed at a thicknesswise bottom end and a first rib  22   b  formed at a thicknesswise top end. 
         [0041]    The second support portion  22   a  is formed along at least a lengthwise portion of the second frame  22  and extends from the thicknesswise bottom end of the second frame  22  toward the cell receiving section  20   a.  Thus, the second support portion  22   a  supports the first long side surface of the bare cell  10  accommodated inside the cell receiving section  20   a  of the cover frame  20 . In addition, in order to increase the supporting capacity of the second support portion  22   a,  the second support portion  22   a  is preferably formed from a lengthwise end of the second frame  22  to the other lengthwise end of the second frame  22 . 
         [0042]    The first rib  22   b  is formed along at least a lengthwise portion of the second frame  22  and extends from the thicknesswise top end of the second frame  22  toward the cell receiving section  20   a.  Thus, the first rib  22   b  supports the second long side surface of the bare cell  10  accommodated inside the cell receiving section  20   a  of the cover frame  20 . The configuration in which the first rib  22   b  is formed in the second frame  22  provides for a superb fixing effect particularly in a wide, thin battery pack having an increased long side surface of the bare cell  10 . In addition, the first rib  22   b  is preferably formed at a central portion of the top end of the second frame  22 , except that the second support portion  22   a  may not be formed at a region corresponding to a region where a first rib  22   b,  which will later be described, is formed. The second support portion  22   a  is for the purpose of stably fixing the bare cell  10  accommodated in the cell receiving section  20   a  of the cover frame  20 . 
         [0043]    As shown in  FIG. 3B , when the cover frame  20  is viewed downwardly from the top, the second support portion  22   a  and the first rib  22   b  are preferably formed so as not to overlap each other. That is to say, the second support portion  22   a  is preferably not formed in an area of the lengthwise region of the second frame  22  corresponding to a region where the first rib  22   b  is formed. This simplifies a molding structure, thereby facilitating fabrication of the cover frame  20  by injection molding and improving the yield of the battery pack  100 . 
         [0044]    The third frame  23  includes a third support portion  23   a  formed at a thicknesswise bottom end and a second rib  23   b  formed at a thicknesswise top end. 
         [0045]    The third support portion  23   a  is formed along at least a lengthwise portion of the third frame  23  and extends from the thicknesswise bottom end of the third frame  23  toward the cell receiving section  20   a.  Thus, the third support portion  23   a  supports the first long side surface of the bare cell  10  accommodated inside the cell receiving section  20   a  of the cover frame  20 . In addition, in order to increase the supporting capacity of the third support portion  23   a,  the third support portion  23   a  is preferably formed from a lengthwise end of the third frame  23  to the other lengthwise end of the third frame  23 , except that the third support portion  23   a  may not be formed at a region corresponding to a region where a second rib  23   b,  which will later be described, is formed. In addition, one end of the third support portion  23   a  is preferably connected to one end of the first support portion  21   a  and the other end the third support portion  23   a  is preferably connected to one end of the second support portion  22   a,  which is for the purpose of increasing the supporting capacity of the support portions  21   a,    22   a  and  23   a.    
         [0046]    The second rib  23   b  is formed along at least a lengthwise portion of the third frame  23  and extends from the thicknesswise top end of the third frame  23  toward the cell receiving section  20   a.  Thus, the second rib  23   b  supports the second long side surface of the bare cell  10  accommodated inside the cell receiving section  20   a  of the cover frame  20 . In addition, the second rib  23   b  is preferably formed at a central portion of the top end of the third frame  23 . This is for the purpose of stably fixing the bare cell  10  accommodated in the cell receiving section  20   a  of the cover frame  20  while facilitating insertion of the bare cell  10  into the cell receiving section  20   a  of the cover frame  20 . 
         [0047]    As shown in  FIG. 3B , when the cover frame  20  is viewed downwardly from the top, the third support portion  23   a  and the second rib  23   b  are preferably formed so as not to overlap each other. That is to say, the third support portion  23   a  may not be formed in an area of the lengthwise region of the third frame  23  corresponding to a region where the second rib  23   b  is formed. Thus, fabrication of the cover frame  20  by injection molding is facilitated, thereby improving the yield of the battery pack  100 . 
         [0048]    The second rib  23   b  is preferably shorter than the third support portion  23   a  in a lengthwise direction of the third frame  23 . This is for the purpose of facilitating insertion of the bare cell  10  into the cell receiving section  20   a  from the top portion of the cover frame  20 . That is to say, in order to insert the bare cell  10  into the cell receiving section  20   a,  it is necessary for the second rib  23   b  to elastically deform upwardly. Therefore, if the second rib  23   b  is formed to be longer than the third support portion  23   a,  it is not easy to insert the bare cell  10  into a region between the second rib  23   b  and the third support portion  23   a.    
         [0049]    The fourth frame  24  includes a fourth support portion  24   a  formed at a thicknesswise bottom end and a third rib  24   b  formed at a thicknesswise top end. 
         [0050]    The fourth support portion  24   a  is formed along at least a lengthwise portion of the fourth frame  24  and extends from the thicknesswise bottom end of the fourth frame  24  toward the cell receiving section  20   a.  Thus, the fourth support portion  24   a  supports the first long side surface of the bare cell  10  accommodated inside the cell receiving section  20   a  of the cover frame  20 . In addition, in order to increase the supporting capacity of the fourth support portion  24   a,  the fourth support portion  24   a  is preferably formed from a lengthwise end of the fourth frame  24  to the other lengthwise end of the fourth frame  24 , except that the fourth support portion  24   a  may not be formed at a region corresponding to a region where a third rib  24   b,  which will later be described, is formed. In addition, one end of the fourth support portion  24   a  is preferably connected to one end of the first support portion  21   a  and the other end the fourth support portion  24   a  is preferably connected to one end of the second support portion  22   a,  which is for the purpose of increasing the supporting capacity of the support portions  21   a,    22   a  and  24   a.    
         [0051]    The third rib  24   b  is formed along at least a lengthwise portion of the fourth frame  24  and extends from the thicknesswise top end of the fourth frame  24  toward the cell receiving section  20   a.  Thus, the third rib  24   b  supports the second long side surface of the bare cell  10  accommodated inside the cell receiving section  20   a  of the cover frame  20 . In addition, the second rib  24   b  is preferably formed at a central portion of the fourth frame  24 . This is for the purpose of stably fixing the bare cell  10  accommodated in the cell receiving section  20   a  of the cover frame  20  while facilitating insertion of the bare cell  10  into the cell receiving section  20   a  of the cover frame  20 . 
         [0052]    As shown in  FIG. 3B , when the cover frame  20  is viewed downwardly from the top, the fourth support portion  24   a  and the third rib  24   b  are preferably formed so as not to overlap each other. That is to say, the fourth support portion  24   a  is preferably not formed in an area of the lengthwise region of the fourth frame  24  corresponding to a region where the third rib  24   b  is formed. This facilitates fabrication of the cover frame  20  by injection molding, thereby improving the yield of the battery pack  100 . 
         [0053]    The third rib  24   b  is preferably shorter than the fourth support portion  24   a  in a lengthwise direction of the fourth frame  24 . This is for the purpose of facilitating insertion of the bare cell  10  into the cell receiving section  20   a  from the top portion of the cover frame  20 . That is to say, in order to insert the bare cell  10  into the cell receiving section  20   a,  it is necessary for the third rib  24   b  to elastically deform upwardly. Therefore, if the third rib  24   b  is formed to be longer than the fourth support portion  24   a,  it is not easy to insert the bare cell  10  into a region between the third rib  24   b  and the fourth support portion  24   a.    
         [0054]    As described above, the ribs,  22   b,    23   b  and  24   b  are centrally located along second, third and fourth frames  22 ,  23  and  24 , and each support section  22   a,    23   a  and  24   a  includes a gap therein formed at a central region of second, third and fourth frames  22 ,  23  and  24  corresponding to a region where each the ribs  22   b,    23   b  and  24   b  are formed. 
         [0055]    Next, a cover frame in a battery pack according to another embodiment of the present invention will be described with reference to  FIGS. 4A to 4C .  FIG. 4A  is a perspective view of a cover frame in a battery pack according to another embodiment of the present invention, and  FIGS. 4B and 4C  are alternative plan views of the cover frame shown in  FIG. 4A . 
         [0056]    Referring to  FIGS. 4A and 4B , the cover frame  30  of the battery pack according to the embodiment of the present invention includes a first frame  31 , a second frame  32  a third frame  33  and a fourth frame  34  surrounding the top surface, the bottom surface and opposing side surfaces of the bare cell  10 . Thus, the bare cell  10  is received in a cell receiving section  30   a  surrounded by the first to fourth frames  31 ,  32 ,  33  and  34 . The cover frame  30  may further include a PCM receiving section  30   b  opposite to, and separated from, the cell receiving section  30   a  by the first frame  31 . 
         [0057]    The first frame  31  includes a first support portion  31   a  formed at a thicknesswise bottom end (edge) and tab receiving grooves  31   b  formed at a thicknesswise top end (edge). 
         [0058]    The second frame  32  includes a second support portion  32   a  formed at a thicknesswise bottom end and a first rib  32   b  formed at a thicknesswise top end. 
         [0059]    The third frame  33  includes a third support portion  33   a  formed at a thicknesswise bottom end and a second rib  33   b  formed at a thicknesswise top end. 
         [0060]    The fourth frame  34  includes a fourth support portion  34   a  formed at a thicknesswise bottom end and a third rib  34   b  formed at a thicknesswise top end. 
         [0061]    The cover frame  30  of the battery pack according to the embodiment of the present invention is substantially the same as the cover frame  20  of the battery pack  100 , except for locations where the second rib  33   b  and the third rib  34   b  are formed, and corresponding where regions of the third support portion  33   a  and the fourth support portion  34   a  are not formed. Therefore, the cover frame  30  of the battery pack according to the embodiment of the present invention will be described with regard to the third support portion  33   a,  the second rib  33   b,  the fourth support portion  34   a  and the third rib  34   b,  and repeated explanations of the other components will not be given. 
         [0062]    The second rib  33   b  may be formed at a location closer to the first frame  31  from a central portion of the third frame  33 . In this case, the third rib  34   b  may be formed at a location closer to the second frame  32  from a central portion of the fourth frame  34 . As described above, the third support portion  33   a  and the fourth support portion  34   a  may not be formed at corresponding locations where the second rib  33   b  and the third rib  34   b  are formed. That is to say, when the cover frame  30  is viewed downwardly from the top, the third support portion  33   a  and the second rib  33   b  are preferably formed so as not to overlap each other, and the fourth support portion  34   a  and the third rib  3   bb  are preferably formed so as not to overlap each other. 
         [0063]    In addition, referring to  FIG. 4C , the second rib  33   b  may be formed at a location closer to the second frame  32  from a central portion of the third frame  33 . In this case, the third rib  34   b  may be formed at a location closer to the first frame  31  from a central portion of the fourth frame  34 . As described above, the third support portion  33   a  and the fourth support portion  34   a  may not be formed at corresponding locations where the second rib  33   b  and the third rib  34   b  are formed. That is to say, when the cover frame  30  is viewed downwardly from the top, the third support portion  33   a  and the second rib  33   b  are preferably formed so as not to overlap each other, and the fourth support portion  34   a  and the third rib  3   bb  are preferably formed so as not to overlap each other. 
         [0064]    As described above, when the second rib  33   b  and the third rib  34   b  are offset from the central portion of third and fourth frames  33  and  34 , the bare cell  10  can be more easily inserted into the cover case  30 , and each support section  32   a,    33   a  and  34   a  includes a gap therein formed at a region corresponding to a region where each the ribs  32   b,    33   b  and  34   b  are formed. 
         [0065]    While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, rather is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.