Abstract:
A battery pack including a battery cell including an electrode assembly, and a case accommodating the electrode assembly therein and including an end wall at a first end, a side wall connected to the end wall and extending toward a second end opposite the first end, and a rounded portion connected between the end wall and the side wall; and an insulation member including a first portion and a second portion, the first portion being on the side wall of the case, and the second portion at least partially covering the rounded portion, an end of the second portion of the insulation member being on the rounded portion.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/368,043, filed on Jul. 27, 2010 in the United States Patent and Trademark Office, the disclosure of which is incorporated herein in its entirety by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    Aspects of embodiments of the present invention relate to a battery pack. 
         [0004]    2. Description of the Related Art 
         [0005]    Secondary batteries are rechargeable, and thus, can be repeatedly used. Such a secondary battery may be manufactured as a battery pack including at least one battery cell. 
         [0006]    The battery pack may be used in portable small devices such as cellular phones, notebooks, computers, cameras, and camcorders, or be used as a power source for driving a motor, e.g., of high output hybrid electric vehicles (HEV), electric vehicles (EV), and electric scooters. 
         [0007]    As such, since the battery pack is installed on an external electronic device, the battery cell is required to have an insulation characteristic to prevent an undesirable short circuit between the battery cell and an external electronic device. 
       SUMMARY 
       [0008]    According to an aspect of embodiments of the present invention, a battery pack provides an insulation characteristic of a battery cell by preventing or substantially preventing an end of an insulation member from being caught and damaged by a partition wall when the battery cell is inserted in a space of a frame. According to another aspect of embodiments of the present invention, a battery pack includes a battery cell having an edge portion wrapped by an insulation member. According to another aspect of embodiments of the present invention, a battery pack provides a robust insulation member between a battery cell and an adjacent wall of a frame. 
         [0009]    According to an embodiment of the present invention, a battery pack includes a battery cell including an electrode assembly, and a case accommodating the electrode assembly therein and including an end wall at a first end, a side wall connected to the end wall and extending toward a second end opposite the first end, and a rounded portion connected between the end wail and the side wall; and an insulation member including a first portion and a second portion, the first portion being on the side wall of the case, and the second portion at least partially covering the rounded portion, an end of the second portion of the insulation member being on the rounded portion. 
         [0010]    In one embodiment, a battery pack further includes at least one partition wall adjacent the battery cell. The insulation member may include an electrically insulative heat shrinkage material. The insulation member may include at least one selected from the group consisting of polycarbonate (PC), polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET). The insulation member may further include ceramic particles. 
         [0011]    In one embodiment, the side wall of the case includes at least one first side wall and at least one second side wall connected to the at least one first side wall, and the insulation member has a tubular shape and continuously surrounds the at least one first side wall and the at least one second side wall. 
         [0012]    The insulation member may have a thickness of about 0.05 mm to about 0.3 mm. The rounded portion may have a radius of curvature of about 1 mm to about 8 mm. An outer surface at the end of the insulation member and an outer surface of the end wall may be substantially coplanar. The rounded portion may protrude toward an exterior of the case. 
         [0013]    In one embodiment, the rounded portion includes a first rounded portion end directly connected to the side wall and a second rounded portion end directly connected to the end wall, an outer surface of the second rounded portion end being coplanar with an outer surface of the end wall. 
         [0014]    The rounded portion may protrude toward an interior of the case. In one embodiment, the first portion of the insulation member includes a planar portion, and the second portion of the insulation member includes a rounded portion. The first and second portions of the insulation member may include a single integral member or separate portions. In one embodiment, the insulation member is not on the end wall. A battery pack may further include a cooling plate contacting the end wall of the case. 
         [0015]    According to another embodiment of the present invention, a battery pack includes a battery cell including an electrode assembly, and a case accommodating the electrode assembly therein and including an end wall at a first end, a side wall connected to the end wall and extending toward a second end opposite the first end, and a rounded portion connected between the end wall and the side wall; and an insulation member on the side wall of the case and at least partially covering the rounded portion, an outer surface of the insulation member and an outer surface of the end wall being substantially coplanar. 
         [0016]    In one embodiment, a distance from an outer surface of the side wall to an end of the insulation member at the first end is less than or equal to 10% of a distance from the outer surface of the side wall to a central axis of the case extending between the first and second ends. 
         [0017]    In one embodiment, the case further includes an extension portion connected between the rounded portion and the end wall and including an outer surface substantially parallel to and spaced apart from an outer surface of the end wall, the insulation member at least partially covering the extension portion. 
         [0018]    In one embodiment, a battery pack further includes at least one partition wall adjacent the battery cell. The battery pack may further include a cooling plate contacting the end wall of the case. The insulation member may extend into a space between the rounded portion and the cooling plate. 
         [0019]    According to another embodiment of the present invention, a battery pack includes; at least one battery cell including a case accommodating an electrode assembly; and an insulation member surrounding side surfaces of the case, wherein the insulation member extends to cover a round part formed between a lower surface and the side surfaces the case. 
         [0020]    According to an aspect of embodiments of the present invention, a battery pack includes an insulation member having an end disposed at a round part of a case, and thus, the end of the insulation member is prevented or substantially prevented from being caught and damaged by a partition wall when a battery cell is inserted in a space of a frame. 
         [0021]    According to another aspect of embodiments of the present invention, a battery pack ensures an insulation characteristic of the battery cell to prevent or substantially prevent an undesirable short circuit between the battery cell and an external electronic device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    The above and other features and advantages will become more apparent to those of ordinary skill in the art by describing in detail some exemplary embodiments of the present invention with reference to the attached drawings. Moreover, additional aspects and/or advantages of embodiments of the present invention are set forth in the following description and accompanying drawings, or may be obvious in view thereof to those skilled in the art. 
           [0023]      FIG. 1  is a perspective view illustrating a battery pack according to an embodiment of the present invention. 
           [0024]      FIG. 2  is an exploded perspective view illustrating a battery cell and a frame of the battery pack of  FIG. 1 . 
           [0025]      FIG. 3  is an exploded perspective view illustrating a battery cell and an insulation member of the battery pack of  FIG. 1 . 
           [0026]      FIG. 4  is a partial cross-sectional view illustrating a lower portion of the battery pack of  FIG. 1 . 
           [0027]      FIG. 5  is an enlarged partial cross-sectional view illustrating a case of a battery cell and an insulation member of the battery pack of  FIG. 4 . 
           [0028]      FIG. 6  is a partial cross-sectional view illustrating an insulation member of a battery pack according to an embodiment of the present invention. 
           [0029]      FIG. 7  is a partial cross-sectional view illustrating a lower portion of a battery pack according to another embodiment of the present invention. 
           [0030]      FIG. 8  is an enlarged partial cross-sectional view illustrating a case of a battery cell and an insulation member of the battery pack of  FIG. 7 . 
           [0031]      FIG. 9  is a partial cross-sectional view illustrating a lower portion of a battery pack according to another embodiment of the present invention. 
           [0032]      FIG. 10  is an enlarged partial cross-sectional view illustrating a case of a battery cell and an insulation member of the battery pack of  FIG. 9 . 
       
    
    
     DESCRIPTION OF REFERENCE NUMERALS INDICATING SOME ELEMENTS IN THE DRAWINGS 
       [0000]    
       
           100 : Battery pack 
           110 : Battery cell 
           120 ,  220 ,  320 : Insulation member 
           130 : Frame 
           140 : Cooling plate 
       
     
       DETAILED DESCRIPTION 
       [0038]    Some exemplary embodiments of the present invention will now be described with reference to the accompanying drawings; however, embodiments of the present invention may be embodied in different forms and should not be construed as limited to the exemplary embodiments illustrated and set forth herein. Rather, these exemplary embodiments are provided by way of example for understanding of the invention and to convey the scope of the invention to those skilled in the art. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Like reference numerals designate like elements throughout the specification and drawings. 
         [0039]      FIG. 1  is a perspective view illustrating a battery pack according to an embodiment of the present invention.  FIG. 2  is an exploded perspective view illustrating a battery cell and a frame of the battery pack of  FIG. 1 .  FIG. 3  is an exploded perspective view illustrating the battery cell and an insulation member of the battery pack of  FIG. 1 .  FIG. 4  is a partial cross-sectional view illustrating a lower portion of the battery pack of  FIG. 1 .  FIG. 5  is an enlarged partial cross-sectional view illustrating a case of the battery cell and an insulation member of the battery pack of  FIG. 4 .  FIG. 6  is a partial cross-sectional view illustrating an insulation member of a battery pack according to an embodiment of the present invention. 
         [0040]    Referring to  FIGS. 1 through 6 , a battery pack  100  according to an embodiment of the present invention includes at least one battery cell  110 , an insulation member  120 , a frame  130 , and a cooling plate  140 . 
         [0041]    The battery cell  110 , in one embodiment, includes an electrode assembly  111  including a positive electrode plate and a negative electrode plate with a separator therebetween, a case  113  having a space accommodating the electrode assembly  111  and electrolyte, a cap assembly  115  coupled to the case  113  and sealing the case  113 , a positive electrode terminal  117  electrically connected to the positive electrode plate and protruding out of the cap assembly  115 , and a negative electrode terminal  119  electrically connected to the negative electrode plate and protruding out of the cap assembly  115 . The case  113  may have an open upper portion to receive the electrode assembly  111 , and include a pair of first side surfaces  113   a , a pair of second side surfaces  113   b , and a lower surface  113   c . The first side surfaces  113   a  may be long side surfaces having a large width, and the second side surfaces  113   b  may be short side surfaces connected between the first side surfaces  113   a  and having a width smaller than the width of the first side surfaces  113   a . The lower surface  113   c  may be connected to the first and second side surfaces  113   a  and  113   b . The case  113  may be formed by performing a deep drawing operation on a metal plate, and a round part Sr protruding outward at connections between the first and second side surfaces  113   a  and  113   b  and the lower surface  113   c  may be formed while forming the case  113 . 
         [0042]    The battery cell  110  may be connected to an external electronic device to perform a discharging operation for supplying power, or may perform a charging operation for receiving power from an external electronic device. 
         [0043]    The insulation member  120 , in one embodiment, surrounds side surfaces of the battery cell  110 , that is, the first and second side surfaces  113   a  and  113   b  of the case  113 . For example, the insulation member  120  may have a single body tube shape to continuously surround the first and second side surfaces  113   a  and  113   b  of the case  113 . That is, the insulation member  120  may be formed as a single seamless part and having a hollow elongated shape. The insulation member  120  extends such that the insulation member  120  covers at least a portion of the round part Sr of the case  113  and does not cover the lower surface  113   c . Accordingly, in one embodiment, a lower end of the insulation member  120  is disposed between a start portion and an end portion of the round part Sr. The start portion of the round part Sr is a portion where the first and second side surfaces  113   a  and  113   b  meet, or connect with, the round part Sr, and the end portion of the round part Sr is a portion where the lower surface  113   c  meets, or connects with, the round part Sr. In addition, in one embodiment, the lower end of the insulation member  120  and the lower surface  113   c  are disposed in the same plane. 
         [0044]    The insulation member  120  prevents or substantially prevents an undesirable short circuit that may be formed between the battery cell  110  and an external electronic device. When the battery cell  110  is inserted in a space  133  of the frame  130 , the insulation member  120  prevents or substantially prevents an end of the insulation member  120  from being caught by a partition wall  134 , and allows heat generated from the battery cell  110  to be emitted through the lower surface  113   c  of the case  113 . 
         [0045]    In one embodiment, the insulation member  120  includes a first insulation side surface  121  and a second insulation side surface  122 . The first insulation side surface  121  may be a long side surface that corresponds to the first side surface  113   a  and extends to the round part Sr, and the second insulation side surface  122  may be a short side surface that corresponds to the second side surface  113   b  and extends to the round part Sr. The insulation member  120  accommodating the battery cell  110  may be closely adhered to the battery cell  110  through a heating process. In one embodiment, in the heating process, heat is applied to the second side surface  113   b  and the round part Sr. This is because the first insulation side surface  121  may be uneven if heat is applied to the first side surface  113   a , by way of example. In a case where the first insulation side surface  121  is uneven, when the battery cell  110  is inserted in the space  133  of the frame  130 , the first insulation side surface  121  closely adhered to the first side surface  113   a  unevenly contacts the partition wall  134  of the frame  130 , and a heat emission efficiency of the battery cell  110  through the frame  130  may be degraded. 
         [0046]    A close adhesion between the insulation member  120  and the case  113  will now be described with respect to the first insulation side surface  121  and the first side surface  113   a . Since a close adhesion between the second insulation side surface  122  and the second side surface  113   b  is the same as that between the first insulation side surface  121  and the first side surface  113   a , a description thereof will be omitted. 
         [0047]    Referring to  FIGS. 4 and 5 , the first insulation side surface  121  is closely adhered to the first side surface  113   a  such that the lower end of the first insulation side surface  121  is disposed at the round part Sr. In one embodiment, the first insulation side surface  121  includes a first insulation planar part  121 P closely adhered to the first side surface  113   a , and a first insulation round part  121 R closely adhered to the round part Sr. The round part Sr, in one embodiment, has a radius of curvature R ranging from about 1 mm to about 8 mm. When the radius of curvature R of the round part Sr is less than 1 mm, a space for forming the first insulation round part  121 R is reduced, and it is difficult to dispose the first insulation round part  121 R at the lower surface  113   c  of the case  113 . In this case, when the battery cell  110  is inserted in the space  133  of the frame  130 , the end of the first insulation side surface  121  comes closer to the partition wall  134 , and thus, is more easily caught by the partition wall  134 . When the radius of curvature R of the round part Sr is greater than 8 mm, a dead space formed between the electrode assembly  111  and the case  113  in the inner space of the case  113  is increased. 
         [0048]    The insulation member  120  may be formed of an electrically insulative heat shrinkage material, for example, at least one of polycarbonate (PC), polypropylene (PP), polyethylene (PE), and polyethyeleneterepthalate (PET). In one embodiment, as illustrated in  FIG. 6 , the insulation member  120  may be formed by adding a material having heat conductivity, such as ceramic particles  120   a , to at least one of polycarbonate (PC), polypropylene (PP), polyethylene (PE), and polyethyeleneterepthalate (PET) to easily emit heat from the battery cell  110 . 
         [0049]    In one embodiment, the insulation member  120  may have a thickness ranging from about 0.05 mm to about 0.3 mm. The insulation member  120  having a thickness of less than 0.05 mm is difficult to form through an injection process, and the insulation member  120  having a thickness greater than 0.3 mm increases the entire thickness of the secondary battery  100 . 
         [0050]    The frame  130 , in one embodiment, includes a pair of first support plates  131 , a pair of second support plates  132  connecting the first support plates  131 , and one or more of the partition walls  134  for forming the space  133  in which the battery cell  110  is inserted. The partition walls  134  may be parallel or substantially parallel to the first support plates  131 . The frame  130 , in one embodiment, is formed of a metal such as aluminum, and emits heat generated from the battery cell  110  to the outside. 
         [0051]    The cooling plate  140 , in one embodiment, is coupled to and contacts a lower portion of the frame  130 . Further, in one embodiment, the cooling plate  140  contacts a lower portion of the battery cell  110  inserted in the space  133  of the frame  130 , for example, the lower surface  113   c  of the case  113 . The cooling plate  140 , in one embodiment, accommodates a cooling water passage and is formed of a metal, so that the cooling water can remove heat generated from the battery cell  110  or heat transferred through the frame  130  from the battery cell  110 . Although not shown, the cooling plate  140  may be connected to a cooling water supply device for supplying cooling water. 
         [0052]    As described above, since the battery pack  100  includes the insulation member  120  with an end disposed at the round part Sr of the case  113 , the insulation member  120  is prevented or substantially prevented from being caught and damaged by the partition wall  134  when the battery cell  110  is inserted in the space  133  of the frame  130 . 
         [0053]    Thus, the battery pack  100  ensures an insulation characteristic of the battery cell  110  to prevent or substantially prevent an undesirable short circuit between the battery cell  110  and an external electronic device. 
         [0054]    A battery pack according to another embodiment of the present invention will now be described. 
         [0055]      FIG. 7  is a partial cross-sectional view illustrating a lower portion of a battery pack according to another embodiment of the present invention, the partial cross-section view corresponding to that of  FIG. 4 .  FIG. 8  is an enlarged partial cross-sectional view illustrating a case of a battery cell and an insulation member of the battery pack of  FIG. 7 . 
         [0056]    The battery pack according to the embodiment of  FIGS. 7 and 8  is the same in configuration and function as the battery pack  100  of  FIG. 1  except for a case  213  and an insulation member  220 . Thus, an illustration and a description of the same configuration will be omitted, and the case  213  and the insulation member  220  will be principally described. 
         [0057]    Referring to  FIGS. 7 and 8 , the case  213  is similar to the case  113  described above and illustrated in  FIGS. 3 and 4 . However, the case  213  includes an extension part Se as well as a round part Sr 1  protruding outward between the lower surface  113   c  and the first and second side surfaces  113   a  and  113   b . The extension part Se extends in parallel or substantially in parallel to the lower surface  113   c  of the case  213  from the round part Sr 1 , and is disposed at a higher position than the lower surface  113   c  of the case  213 . Accordingly, a receiving space Ss 1 , or accommodation space, is formed between the first side surface  113   a  and the lower surface  113   c  of the case  213  to receive the insulation member  220  at the outside of the extension part Se. A distance Dp between the first side surface  113   a  and the lower surface  113   c  may be equal to or less than 10% of a distance Dc between a central axis C and the first side surface  113   a  of the case  213 . This is because heat generated from the battery cell  110  that is being emitted through the lower surface  113   c  of the case  213  may be reduced if the distance Dp is greater than 10% of the distance Dc. 
         [0058]    In one embodiment, the insulation member  220  has a first insulation side surface  221  and a second insulation side surface (not shown), which are similar to the first and second insulation side surfaces  121  and  122  described above and illustrated in  FIGS. 3 and 4 . However, the first insulation side surface  221  may be a long side surface that corresponds to the first side surface  113   a  and passes by the round part Sr and extends to the accommodation space Ss 1 , and the second insulation side surface (not shown) may be a short side surface that corresponds to the second side surface  113   b  (refer to  FIG. 3 ) and passes by the round part Sr and extends to the accommodation space Ss 1 . Hereinafter, among the first insulation side surface  221  and the second insulation side surface (not shown), the first insulation side surface  221  will now be described in further detail, by way of example. 
         [0059]    The first insulation side part  221  has a lower end that is disposed in the accommodation space Ss 1  of the case  213 . In one embodiment, the first insulation side surface  221  includes a first insulation planar part  221 P closely adhered to the first side surface  113   a , a first insulation round part  221 R closely adhered to the round part Sr 1 , and a first insulation extension part  221 E accommodated in the accommodation space Ss 1 . 
         [0060]    Since the second insulation side surface (not shown) may be the same as the first insulation side surface  221  except for its width, a description thereof will be omitted. 
         [0061]    As described above, since the insulation member  220  of the battery pack according to the embodiment shown in  FIGS. 7 and 8  is accommodated in the accommodation space Ss 1  of the case  213  such that the insulation member  220  is stably disposed at the lower side of the case  213 , the end of the insulation member  220  is effectively prevented or substantially prevented from being caught and damaged by the partition wall  134  when the battery cell  110  is inserted in the space  133  of the frame  130 , and heat generated from the battery cell  110  is emitted through the lower surface  113   c  of the case  213 . 
         [0062]    Thus, the battery pack described above according to an embodiment of the present invention effectively ensures an insulation characteristic of the battery cell  110  to prevent or substantially prevent an undesirable short circuit between the battery cell  110  and an external electronic device. 
         [0063]    A battery pack according to another embodiment of the present invention will now be described. 
         [0064]      FIG. 9  is a partial cross-sectional view illustrating a lower portion of a battery pack according to another embodiment of the present invention, the partial cross-sectional view corresponding to that of  FIG. 4 .  FIG. 10  is an enlarged partial cross-sectional view illustrating a case of a battery cell and an insulation member of the battery pack of  FIG. 9 . 
         [0065]    The battery pack according to the embodiment of  FIGS. 9 and 10  is the same in configuration and function as the battery pack  100  of  FIG. 1  except for a case  313  and an insulation member  320 . Thus, an illustration and a description of the same configuration will be omitted, and the case  313  and the insulation member  320  will be principally described. 
         [0066]    Referring to  FIGS. 9 and 10 , the case  313  is similar to the case  113  described above and illustrated in  FIGS. 3 and 4 . However, the case  313  includes a round part Sr 2  between the lower surface  113   c  and each of the first and second side surfaces  113   a  and  113   b , and the round part Sr 2  protrudes to the inside of the case  313 . Accordingly, an accommodation space Ss 2 , which accommodates the insulation member  320  at the outside of the round part Sr 2  between the lower surface  113   c  and each of the first and second side surfaces  113   a  and  113   b  is formed. 
         [0067]    In detail, the insulation member  320  has a first insulation side surface  321  and a second insulation side surface (not shown), which are similar to the first and second insulation side surfaces  121  and  122  described above and illustrated in  FIGS. 3 and 4 . However, the first insulation side surface  321  may be a long side surface that corresponds to the first side surface  113   a  and extends to be accommodated in the accommodation space Ss 2 , and the second insulation side surface (not shown) may be a short side surface that corresponds to the second side surface  113   b  (refer to  FIG. 3 ) and extends to be accommodated in the accommodation space Ss 2 . Hereinafter, among the first insulation side surface  321  and the second insulation side surface (not shown), the first insulation side surface  321  will now be described in further detail, by way of example. 
         [0068]    The first insulation side part  321  has a lower end that is disposed in the accommodation space Ss 2 . In one embodiment, the first insulation side surface  321  includes a first insulation planar part  321 P closely adhered to the first side surface  113   a , and a first insulation round part  321 R accommodated in the accommodation space Ss 2 . 
         [0069]    Since the second insulation side surface (not shown) may be the same as the first insulation side surface  321  except for its width, a description thereof will be omitted. 
         [0070]    As described above, since the insulation member  320  of the battery pack according to the embodiment of  FIGS. 9 and 10  is accommodated in the accommodation space Ss 2  of the case  313  such that the insulation member  320  is stably disposed at the lower side of the case  313 , the end of the insulation member  320  is effectively prevented or substantially prevented from being caught and damaged by the partition wall  134  when the battery cell  110  is inserted in the space  133  of the frame  130 , and heat generated from the battery cell  110  is emitted through the lower surface  113   c  of the case  313 . 
         [0071]    Thus, the battery pack described above according to an embodiment of the present invention effectively ensures an insulation characteristic of the battery cell  110  to prevent or substantially prevent an undesirable short circuit between the battery cell  110  and an external electronic device. 
         [0072]    Some exemplary embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.