Abstract:
A battery module including a plurality of battery cells; and a housing accommodating the battery cells, the housing comprising a side plate, a bottom plate, and a bending portion between the side plate and the bottom plate, wherein the bending portion is configured to bias the side plate and the bottom plate toward the battery cells.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to and the benefit of U.S. Provisional Application No. 61/806,745, filed on Mar. 29, 2013 in the U.S. Patent and Trademark Office, the entire content of which is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    An aspect of the present invention relates to a battery module. 
         [0004]    2. Description of the Related Art 
         [0005]    A high-power battery module using a non-aqueous electrolyte with high energy density has recently been developed. The high-power battery module is configured as a large-capacity battery module manufactured by connecting a plurality of battery cells in series to be used for driving devices, e.g., motors of electric vehicles and the like, which require high power. 
         [0006]    The battery module includes a plurality of battery cells based on a specified output voltage and current. The battery module also includes a frame for firmly fixing the battery cells. When a tolerance with which the width of the battery cells is greater or smaller than that of the frame, the battery cells may not be able to be firmly fixed by the frame. 
       SUMMARY 
       [0007]    Embodiments provide a battery module in which a frame is adhered closely to battery cells even when there is a tolerance with which the width of the battery cells is greater or smaller than that of the frame, so that the battery cells can be firmly fixed by the frame. 
         [0008]    According to an aspect of the present invention, there is provided a battery module, including: one or more battery cells arranged in one direction; a pair of side plates disposed to come in surface contact with sides of the battery cells; and a bottom plate formed to extend from the pair of side plates, and facing bottoms of the battery cells, wherein a bending portion having a sectional shape convex to an outside of the battery module so that the side plate is moved in the side direction of the battery cell or in the opposite direction of the side of the battery cell is formed in a region where the side plate and the bottom plate are connected to each other. 
         [0009]    The convex sectional shape may be a round shape. 
         [0010]    When the length of the battery cell in the width direction is smaller than the interval between the pair of side plates, the round shape may be changed by a force applied in the side direction of the battery cell from the outside, and the side plate may be horizontally moved in the side direction of the battery cell. 
         [0011]    When the length of the battery cell in the width direction is greater than the interval between the pair of side plates, the round shape may be changed by a force applied in the opposite direction to the side of the battery cell from the outside, and the side plate may be horizontally moved in the opposite direction to the side of the battery cell. 
         [0012]    The bending portion may include a first extending portion extended from the bottom plate, and a second extending portion extended diagonally with respect to the side direction of the battery cell from the first extending portion. 
         [0013]    When the length of the battery cell in the width direction is smaller than the interval between the pair of side plates, the angle formed between the first and second extending portions may be decreased by the force applied in the side direction of the battery cell from the outside, and the side plate may be horizontally moved in the side direction of the battery cell. 
         [0014]    When the length of the battery cell in the width direction is greater than the interval between the pair of side plates, the angle formed between the first and second extending portions may be increased by the force applied in the side direction of the battery cell from the outside, and the side plate may be horizontally moved in the opposite direction to the side of the battery cell. 
         [0015]    The side plate may be formed to extend in the direction parallel with the side of the battery cell from the second extending portion. 
         [0016]    The bending portion may further include a cut-away groove formed between the first and second extending portions. 
         [0017]    The battery module may further include a pair of end plates respectively coming in surface contact with the outermost battery cells among the battery cells, and a top cover covering tops of the battery cells. 
         [0018]    One end of the side plate may be fastened to one end of the end plate through laser welding. 
         [0019]    The side plate may include at least one first fastening portion fastened to the top cover, and the bottom plate may include at least one first fastening portion fastened to the end plate. 
         [0020]    The top cover may include at least one first fastening portion fastened to the side plate, and at least one second fastening portion fastened to the end plate. 
         [0021]    The end plate may include at least one first fastening portion fastened to the top cover, and at least one second fastening portion fastened to the bottom plate. 
         [0022]    The first fastening portion of the side plate and the first fastening portion of the top cover, the second fastening portion of the top cover and the first fastening portion of the end plate, or the second fastening portion of the end plate and the first fastening portion of the bottom plate may be fastened to each other by the medium of a fastening member or through laser welding. 
         [0023]    The fastening member may be a bolt-nut or stud. 
         [0024]    The side plate may have at least one opening formed therein. 
         [0025]    According to the present invention it is possible to a battery module capable of absorbing a width tolerance. 
         [0026]    Accordingly, a frame can come in surface contact with battery cells, regardless of the size of the battery cells in the width direction, thereby firmly fixing the battery cells. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    The accompanying drawings, together with the specification, illustrate exemplary embodiments of the present invention, and, together with the description, serve to explain the principles of the present invention. 
           [0028]      FIG. 1  is a perspective view schematically showing a battery module according to an embodiment of the present invention. 
           [0029]      FIG. 2  is an exploded perspective view of  FIG. 1 . 
           [0030]      FIGS. 3A to 3C  are enlarged sectional views showing region A of  FIG. 1 . 
           [0031]      FIGS. 4A and 4B  are partial enlarged sectional views showing a front lower portion of the battery module when no bending portion is formed. 
           [0032]      FIGS. 5A to 5C  are partial enlarged sectional views showing a front lower portion of a battery module according to another embodiment of the present invention. 
           [0033]      FIG. 6  is a partial enlarged sectional view showing a front lower portion of a battery module according to still another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    In the following detailed description, only certain exemplary embodiments of the present invention have been shown and described, simply by way of illustration. 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. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. In addition, when an element is referred to as being “on” another element, it can be directly on the another element or be indirectly on the another element with one or more intervening elements located therebetween. Also, when an element is referred to as being “connected to” another element, it can be directly connected to the another element or be indirectly connected to the another element with one or more intervening elements located therebetween. Hereinafter, like reference numerals refer to like elements. 
         [0035]      FIG. 1  is a perspective view schematically showing a battery module according to an embodiment of the present invention.  FIG. 2  is an exploded perspective view of  FIG. 1 . 
         [0036]    The battery module  100  according to this embodiment includes a plurality of battery cells  10  arranged in one direction and each having electrode terminals  11  and  12 . In this case, the battery cells  10  are arranged so that wide surfaces of adjacent battery cells  10  face each other. 
         [0037]    Each of the battery cells  10  constituting the battery module  100  may be manufactured by accommodating an electrode assembly and an electrolyte in a battery case and then sealing the battery case in which the electrode assembly is accommodated using a cap plate  14 . In one embodiment, the electrode assembly includes a positive electrode plate and a negative electrode plate and a separator located between these electrode plates. The cap plate  14  may be provided with electrode terminals protruded to the outside thereof. The electrode terminals may be positive and negative electrode terminals  11  and  12  respectively connected to the positive and negative electrode plates. The positive and negative electrode plates may generate electrochemical energy by reacting with the electrolyte. Accordingly, the generated energy is transferred to the outside of the battery cell  10  through the positive and negative electrode terminals  11  and  12 . A vent is provided in the cap plate  14  between the positive and negative electrode terminals  11  and  12 , to serve as a passage through which gas is exhausted to the outside of the battery cell  10 . 
         [0038]    In this embodiment, a case where the battery cell  10  is a prismatic secondary battery will be described as an example. However, the present invention is not limited thereto and may be applied to various types of batteries including a lithium polymer battery, a cylindrical battery, and the like. 
         [0039]    A housing member  110  according to this embodiment includes a pair of end plates  112  respectively coming in surface contact with the outermost battery cells  10  among the plurality of battery cells  10 , a pair of side plates  113  located between the pair of end plates  112 , and coming in surface contact with surfaces of the battery cells  10 , and a bottom plate  114  facing bottoms of the battery cells  10 . In one embodiment, the bottom plate  114  may be extended in the vertical direction from the pair of side plates  113  so as to be integrally formed with the side plates  113 . 
         [0040]    The side plate  113  has at least one first fastening portion  113   a   1  fastened to a top cover  115 , and a first fastening opening  113   a   2  is formed in the first fastening portion  113   a  of the side plate  113 . 
         [0041]    The bottom plate  114  has at least one fastening portion  114   a   1  fastened to the end plate  112 , and a fastening opening  114   a   2  is formed in the fastening portion  114   a   1  of the bottom plate  114 . 
         [0042]    The top cover  115  has at least one first fastening portion  115   a   1  fastened to the side plate  113  and at least one second fastening portion  115   b   1  fastened to the end plate  112 . First and second fastening openings  115   a   2  and  115   b   2  are respectively formed in the first and second fastening portions  115   a   1  and  115   b   1  of the top cover  115 . 
         [0043]    The end plate  112  has at least one first fastening portion  112   a   1  fastened to the top cover  115  and at least one second fastening portion  112   c   1  fastened to the bottom plate  114 . First and second fastening openings  112   a   2  and  112   c   2  are respectively formed in the first and second fastening portions  112   a   1  and  112   c   1  of the end plate  112 . 
         [0044]    The first and second end plates  112  are oriented to come in surface contact with the respective outermost battery cells  10 , thereby pressurizing the plurality of battery cells  10  to the inside thereof, i.e., compressing the battery cells together. The side plate  113  connects the first and second end plates  112  to each other. One end of the side plate  113  is fastened to the first end plate  112 , and the other end of the side plate  113  is fastened to the second end plate  112 . In one embodiment, the first and second end plates  112  may be fasted to the side plate  113  through laser welding. 
         [0045]    The side plates  113  provide a space in which the plurality of battery cells  10  can be aligned by connecting the first and second end plates  112  to each other, and simultaneously support both sides of the battery cells  10 . Referring to  FIG. 2 , it has been described in this embodiment that the side plates  113  support both the sides of the battery cells  10  and have openings  0  for a coolant flow path, which are formed therein. However, the shape and the like of the side plate  113  may be freely modified according to the design of the battery module  100 . The battery cells  10  are fixed in the space defined by the first and second end plates  112  and the side plates  113  so as not to be easily moved by an external impact. 
         [0046]    A barrier  30  may be located between adjacent battery cells  10 . A spacer is provided in each barrier  30  to space the plurality of adjacent battery cells  10  from each other and to form a space between the battery cells  10 . Accordingly, it is possible to provide the flow path of a coolant for cooling the battery cells  10 . 
         [0047]    The battery module  100  may further include a bus-bar  20  connecting the positive and negative electrodes  11  and  12  of the adjacent battery cells  10 , and a shielding wall  21  surrounding adjacent bus-bars  20 . 
         [0048]    The shielding wall  21  may be provided to partition a plurality of bus-bars  20  electrically connecting the electrode terminals  11  and  12  of the adjacent battery cells  10 . Thus, it is possible to prevent a short circuit between adjacent bus-bars  20  and to prevent a short circuit caused by an electric conductor made of metal such as a bolt-nut, which is a material used in the battery module  100 . 
         [0049]    In this embodiment, the fastening portion  113   a   1 ,  114   a   1 ,  115   a   1 ,  115   b   1 ,  112   a   1  or  112   c   1  and the fastening opening  113   a   2 ,  114   a   2 ,  115   a   2 ,  115   b   2 ,  112   a   2  or  112   c   2  may be fastened to each other by a fastening member such as a bolt-nut or stud. When necessary, the fastening portion and the fastening opening may be fastened to each other through welding. 
         [0050]      FIGS. 3A to 3C  are enlarged sectional views showing region A of  FIG. 1 . 
         [0051]    Referring to  FIGS. 3A to 3C , a bending portion  116  is formed in a region where the side plate  113  and the bottom plate  114  are connected to each other. The bending portion  116  has a sectional shape protruding outward so that the side plate  113  can be moved in a side direction of the battery cell  10  or in the opposite direction thereto. 
         [0052]    According to one embodiment, the sectional shape of the bending portion  116  may be a round shape. 
         [0053]    For example, in a case where the length of the battery cell  10  in the width direction is smaller than the interval between the pair of side plates  113 , the side plate  113  may be horizontally moved in a side direction of the battery cell  10  through a change in the bending portion  116  as shown in  FIG. 3B . That is, the side plate  113  is moved in the side direction of the battery cell  10  by a force applied from the outside, thereby coming in surface contact with the side of the battery cell  10 . 
         [0054]    In a case where the length of the battery cell  10  in the width direction is greater than the interval between the pair of side plates  113 , the side plate  113  may be moved in the opposite direction to the side direction of the battery cell  10  through a change in the bending portion  116  as shown in  FIG. 3C . That is, the battery cell  10  is inserted into a space formed between the side plate  113  and the bottom plate  114  through the horizontal movement of the side plate  113 , thereby assembling the battery pack. When the battery cell  10  is inserted into the space formed between the side plate  113  and the bottom plate  114 , the side plate  113  comes in surface contact with the side of the battery cell  10 . 
         [0055]      FIGS. 4A and 4B  are partial enlarged sectional views showing a front lower portion of the battery module when no bending portion is formed. 
         [0056]    In a case where no bending portion is formed, a side plate  413  may be formed to protrude in the vertical direction from a bottom plate  414 . 
         [0057]    In a case where the length of the battery cell  10  in the width direction is smaller than the interval between the pair of side plates  413 , a void occurs between the side plate  413  and a side of the battery cell  10  as shown in  FIG. 4A . Although the side plate  413  is moved in the side direction of the battery cell  10 , the side plate  413  may not come into surface contact with the side of the battery cell  10 . 
         [0058]    When the length of the battery cell  10  in the width direction is greater than the interval between the pair of side plates  413 , the battery cell  10  may not be able to be assembled in a space formed between the side plate  413  and the bottom plate  414  as shown in  FIG. 4B . 
         [0059]    Accordingly, in the battery module according to this embodiment, the bending portion  116  is formed in the region where the side plate  113  and the bottom plate  114  are connected to each other as described in  FIG. 3 , so that the side of the battery cell  10  can come in surface contact with the side plate  113  even if the width direction of the battery cell  10  is not constant. 
         [0060]      FIGS. 5A to 5C  are partial enlarged sectional views showing a front lower portion of a battery module according to another embodiment of the present invention. 
         [0061]    Referring to  FIG. 5A , a bending portion  516  having a sectional shape convex to the outside of the battery module is formed in the region where a side plate  513  and a bottom plate  514  are connected to each other. 
         [0062]    The bending portion  516  may include a first extending portion  516   a  extended from the bottom plate  514 , and a second extending portion  516   b  extended diagonally with respect to the side direction of the battery cell  10  from the first extending portion  516   a.    
         [0063]    In this case, the side plates  513  may be formed to extend in the direction parallel with the side of the battery cell  10  from the second extending portion  516   b.    
         [0064]    Although it has been illustrated in  FIG. 5A  that the first extending portion  516   a  is formed to extend in the direction parallel with the bottom plate  514 , the first extending portion  516   a  may be formed to extend while having an inclination of 90 degrees or less. 
         [0065]    For example, in a case where the length of the battery cell  10  in the width direction is smaller than the interval between the pair of side plates  513 , the angle formed between the first and second extending portions  516   a  and  516   b  may be decreased through a force applied in the side direction of the battery cell  10  from the outside as shown in  FIG. 5B . Accordingly, the side plate  513  is horizontally moved in the side direction of the battery cell  10 , so that the side plate  513  can come in surface contact with the side of the battery cell  10 . 
         [0066]    In a case where the length of the battery cell  10  in the width direction is greater than the interval between the pair of side plates  513 , the angle formed between the first and second extending portions  516   a  and  516   b  can be increased through a force applied in the opposite direction to the side of the battery cell  10  from the outside as shown in  5 C. In this case, the side plate  513  is horizontally moved in the opposite direction to the side of the battery cell  10 . Thus, in a case where the length of the battery cell  10  in the width direction is greater than the interval between the pair of side plates  513 , the battery cell  10  can be inserted into a space formed between the side plate  513  and the bottom plate  514 , and the side plate  513  can come in surface contact with the side of the battery cell  10  in the insertion of the battery cell  10 . 
         [0067]      FIG. 6  is a partial enlarged sectional view showing a front lower portion of a battery module according to still another embodiment of the present invention. 
         [0068]    Referring to  FIG. 6 , components in this embodiment except a bending portion  516  are identical to those in the embodiment shown in  FIG. 5 . Therefore, like components are designated by like reference numerals, and their detailed descriptions will be omitted. 
         [0069]    As shown in  FIG. 6 , the bending portion  516  may include a first extending portion  516   a  extended from the bottom plate  514 , a second extending portion  516   b  extended diagonally with respect to the side direction of the battery cell  10  from the first extending portion  516   a,  and a cut-away groove  516   c  formed between the first and second extending portions  516   a  and  516   b.    
         [0070]    Here, the cut-away groove  516   c  may perform a function of facilitating a change in the second extending portion  516   b  in the lateral direction. 
         [0071]    As described above, the bending portion  116  or  516  enabling the side plate  113  or  513  to be moved is formed in the region where the side plate  113  or  513  and the bottom plate  114  or  514  are connected to each other, so that the side plate  113  or  513  can come in surface contact with the side of the battery cell  10  even when there occurs a tolerance between the length of the battery cell  10  in the width direction and the interval between the pair of side plates  113  or  513 . In other words, a frame can come in surface contact with the battery cell, regardless of the length of the battery cell in the width direction, so that the battery cells can be firmly fixed by the frame. 
         [0072]    While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, and equivalents thereof.