Abstract:
A battery is mounted in a hybrid electric automotive vehicle. The battery is held by a restraining bar across top surfaces of a plurality of cells that comprise the battery. A holder is located between the cells and restraining bar to increase a contact area between the restraining bar and the battery.

Description:
BACKGROUND OF INVENTION 
       [0001]    The present invention relates to automotive traction batteries and in particular to a system for mounting traction batteries in a hybrid electric automotive vehicle. 
         [0002]    A hybrid powertrain of an automotive vehicle includes a battery comprised of a plurality of cells. Typically, the battery is secured in the vehicle by clamping a restraining bar across a top surface of the cells. The restraining bar may be fabricated from a high strength, and electrically conductive, material such as steel or from a high strength, electrically non-conductive material such as fiber-reinforced polymer. 
         [0003]    However, battery features or components on the top surface of the battery cell may reduce the effectiveness of the restraining bar. The restraining bar is applied to a contact area of the top surface. The potential contact area is commonly reduced by one or more electrical terminals on the top surface. The terminal both reduces the top surface available for the contact area and, when an electrically conductive restraining bar is used, requires electrical isolation from the restraining bar. 
       SUMMARY OF INVENTION 
       [0004]    An embodiment contemplates a vehicle battery mounting system. A battery assembly has a cell. A terminal is fixed to the cell. An insulating holder is located between a top surface of the cell and the terminal, wherein the holder extends, in a direction normal to the top surface, farther out than a portion of the terminal. A restraint secures the cell such that the holder prevents the restraint from contacting the terminal. 
         [0005]    Another embodiment contemplates a method of mounting a battery cell in a vehicle. A terminal is fixed to the cell. An insulating holder is placed between a top surface of the cell and the terminal, wherein the holder extends, in a direction normal to the top surface, farther out than a portion of the terminal. The holder is fixed between the battery and a restraint, such that the holder prevents the restraint from contacting the terminal. 
         [0006]    Another embodiment contemplates a method of mounting a battery assembly in a vehicle. An insulating holder is placed between a top surface of the battery and a restraint, wherein the holder extends, in a direction normal to the top surface, farther out than a terminal of the battery. The holder is secured between the battery and restraint, such that the holder prevents the restraint from contacting the terminal. 
         [0007]    An advantage of an embodiment is a contact area for the restraint is increased. This improves effectiveness of the restraint securing the battery. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]      FIG. 1  is a schematic perspective view of a battery restraint according to the prior art. 
           [0009]      FIG. 2  is a schematic sectional view of a portion of a prior art battery restraint, taken along line  2 - 2  of  FIG. 1 . 
           [0010]      FIG. 3  is a schematic perspective view of a battery mounting system according to the present invention. 
           [0011]      FIG. 4  is a schematic sectional view of a portion of a battery mounting system, taken along line  4 - 4  of  FIG. 3 . 
           [0012]      FIG. 5  is a schematic sectional view of a portion of a battery mounting system, similar to  FIG. 4 , but illustrating a different embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]      FIGS. 1 and 2  schematically illustrate a prior art battery securing system  10  for a battery assembly  12  in an automotive vehicle  14 . Multiple cells  16 , having cell shoulder contact areas  18 , are arranged for mounting in the vehicle  14 . A restraint  20  is placed across the cell shoulders  18 . The restraint  20  is secured to an anchor  22  to exert a downward force (indicated by arrow  24 ) on the cell shoulders  18 . The downward force  24  secures the battery  12  in the vehicle  14 . The downward force  24  is illustrated as applied to a left cell shoulder of the cells  16 , but as understood by one skilled in the art, the downward force  24  may also be applied to a right cell shoulder opposite the left cell shoulder or both the left and right cell shoulders. 
         [0014]    Each cell  16  includes a cell top surface  26 , which includes the shoulder  18 . The restraint  20  is in contact with the shoulder  18  in a shoulder contact area  38 . An insulator  28  is positioned on the cell top surface  26 . The insulator  28  may include a perimeter wall  29  having a top surface  27 . A terminal  30  is positioned in the insulator  28 . The terminal  30  extends through the cell top surface  26  and insulator  28 . The terminal  30  is fixed to the cell  16  by a suitable means known to one skilled in the art. For example, the terminal  30  may be fixed to the cell  16  by welding. The insulator  28  may be used to locate or position the terminal  30  prior to fixing the terminal  30  to the cell  16 . The terminal  30  may be used to restrain the insulator  28  while the terminal  30  is fixed to the cell  16 . The terminal  30  is electrically connected to a high voltage bus of the vehicle  14 . 
         [0015]      FIGS. 3 and 4  illustrate a battery mounting system  110  for a battery assembly  112  in an automotive vehicle  114 . Multiple cells  116 , having cell shoulder contact areas  118 , are arranged for mounting in the vehicle  114 . A restraint  120  is placed across the cells  116 . The restraint  120  is secured to an anchor  122  to exert a downward force (indicated by arrow  124 ) on the cell shoulder  118 . The downward force  124  secures the cells  116  in the vehicle  114 . The downward force  124  is illustrated as applied to a left cell shoulder of the cells  116 , but as understood by one skilled in the art, the downward force  124  may also be applied to a right cell shoulder opposite the left cell shoulder or both the left and right cell shoulders. 
         [0016]    Each cell  116  includes a top surface  126 . A holder  136  is positioned on the top surface  126 . The holder  136  incorporates insulator and extension portions  128  and  138 , respectively. A terminal  130  is positioned in the insulator portion  128 . The terminal  130  extends through the top surface  126  and insulator portion  128 . The terminal  130  is fixed to the cell  116  by a suitable means known to one skilled in the art. For example, the terminal  130  may be fixed to the cell  116  by welding. The insulator portion  128  may be used to locate or position the terminal  130  prior to fixing the terminal  130  to the cell  16 . The terminal  130  may be used to restrain the insulator portion  128  while the terminal  130  is fixed to the cell  116 . The terminal  130  is electrically connected to a high voltage bus of the vehicle  114 . 
         [0017]    The terminal  130  has a lower portion  140  and an upper portion  142 . The upper portion  142  is farther out, in a vertical direction  144  normal to the top surface  126 , from the top surface  126  than the lower portion  140 . The extension portion  138  of the holder  136  extends farther out, in the vertical direction  144 , from the top surface  126  than the lower portion  140 . This allows the restraint  120  to extend, in a horizontal direction  146  parallel to the top surface  126 , and increase a contact area  148  between the restraint  120  and holder  136 . 
         [0018]    The upper portion  142  of the terminal  130  may be electrically connected to the high voltage bus while the lower portion  140  is not connected to the high voltage bus. The high voltage bus not being connected to the lower portion  140  further allows the restraint  120  to extend, in the horizontal direction  146 , over the lower portion  140 . Extending of the restraint  120  may end such that the restraint  120  does not exist over upper portion  142  which, as described, is required to connect to the high voltage bus of the vehicle  114   
         [0019]    Alternatively, the extension portion  138  may extend farther out, in the vertical direction  144 , from the top surface  126  than the lower portion  140  and the upper portion  142 . As illustrated, the terminal  130  has lower and upper portions  140  and  142 , respectively. The upper portion  142  may electrically connect the terminal  130  and the high voltage bus. Alternatively, the terminal  130  may have any suitable shape known to one skilled in the art and the extension portion  138  may extend farther out, in the vertical direction  144 , than the terminal  130 . 
         [0020]    For a same sized battery cell, the contact area  148  is larger than the shoulder contact area  38  (shown in  FIG. 2 ), which allows the downward force  124  to be distributed over a greater area. Likewise, as the restraint  120  extends farther in the horizontal direction  146  over the lower portion  140 , an increased relative positional tolerance between the restraint  120  and the cell  116  is allowed while still maintaining the proportion of the contact area  148 . 
         [0021]    Alternatively, the extension portion  138  may extend farther, in the vertical direction  144 , than the upper portion  142 , which allows the restraint  120  to extend even farther in the horizontal direction  146 . For example, the extension portion  138  may extend farther in the vertical direction  144  such that the restraint  120  may extend in the horizontal direction  146  over a portion of the upper portion  142  without contacting the upper portion  142 . 
         [0022]    The holder  136  separates the restraint  120  from the top surface  126 . Additionally, the holder  136 , including the extension portion  138 , may be fabricated from an insulating material. 
         [0023]    The holder  136  may be secured to the top surface  126  such that the holder  136  does not extend in the horizontal direction  146  beyond an extent of the top surface  126 . The downward force  124  may clamp the holder  136  between the restraint  120  and the battery  112 . 
         [0024]    The restraint  120  may have an insulating layer  150  to prevent a possible electrical short between the restraint  120  and any of the top surface  126  or terminal  130 . 
         [0025]      FIG. 5  illustrates a battery mounting system  210 . Because the battery mounting system  210  is a variation of the battery mounting system  110  of  FIGS. 3 and 4 , like reference numerals, incremented by  100 , designate corresponding parts in the drawings and detailed description thereof will be omitted. 
         [0026]    As one skilled in the art will understand, a holder  236  may be comprised of separate insulator and extension portions  228  and  238 , respectively, meeting at an interface  252 . The illustrated arrangement of the interface  252  is a non-limiting example. The interface  252  may be by any suitable means known to one skilled in the art. As one skilled in the art will understand, the extension portion  238  may span between multiple of the cells in the battery. 
         [0027]    While certain embodiments of the present invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims.