Abstract:
A grommet for coupling battery modules includes two coupling portions. A hinge portion connects the coupling portions at first ends thereof. A first hook structure connects the coupling portions at second ends thereof. A second hook structure connects the coupling portions at centers thereof. When the hook structures are hooked, the grommet defines two battery module receiving spaces therein.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under 35 U.S.C. §119(a) of Korean Patent Application No. 10-2007-0061081, filed on Jun. 21, 2007, the entire contents of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    (a) Field of the Invention 
         [0003]    The present invention relates to a grommet for coupling two battery modules together. 
         [0004]    (b) Background Art 
         [0005]    Typically, a battery unit including two or more battery modules is mounted in a hybrid vehicle or in an electric vehicle such as a fuel cell vehicle. The battery modules should be coupled to each other at regular intervals. 
         [0006]    A typical grommet includes two components coupled to each other. The number and cost of components, as well as the time and cost of assembly, are thus unnecessarily high. Moreover, the strength of the connection between the components may not be sufficient. 
         [0007]    The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art. 
       SUMMARY OF THE INVENTION 
       [0008]    A grommet for coupling battery modules includes two coupling portions. A hinge portion connects the coupling portions at first ends thereof. A first hook structure connects the coupling portions at second ends thereof. A second hook structure connects the coupling portions at centers thereof. When the hook structures are hooked, the grommet defines two battery module receiving spaces therein. 
         [0009]    The first ends of the coupling portions may include notches such that the hinge portion is separated from the remainder of the first ends. 
         [0010]    The hinge portion&#39;s ends may be thicker than its central portion. 
         [0011]    The second hook structure may include at least one hook protruding from one of the coupling portions, and at least one hole in the other coupling portion. The hole may have a hook engaging projection therein, configured for the hook to be inserted into the hole and engaged with the hook engaging projection. The hook may include a reinforcing rib. 
         [0012]    The first hook structure may include a hook protruding from one of the coupling portions, and a hook engaging projection on the other coupling portion, configured for the hook to be engaged thereon. The hook and the hook engaging projection may be tapered. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIGS. 1 and 2  are perspective views showing two battery modules coupled to each other by exemplary grommets; 
           [0014]      FIG. 3  is a cross-sectional view showing battery modules coupled by exemplary grommets loaded in a battery holder; 
           [0015]      FIG. 4  is a perspective view of an exemplary grommet; 
           [0016]      FIGS. 5 to 8  are detailed diagrams of an exemplary hinge portion between two coupling portions of a grommet; 
           [0017]      FIGS. 9 to 11  are detailed diagrams of an exemplary hook engaging structure between middle portions of a grommet; and 
           [0018]      FIGS. 12 to 15  are detailed diagrams of an exemplary hook engaging structure between end portions of a grommet. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Reference will now be made in detail to a preferred embodiment of the present invention, examples of which are illustrated in the drawings attached hereinafter, wherein like reference numerals refer to like elements throughout. The embodiments are described below so as to explain the present invention by referring to the figures. 
         [0020]    The present invention provides a grommet for coupling two battery modules to constitute a single battery unit. 
         [0021]    The grommet for coupling battery modules of the present invention is composed of a single component. A hinge portion is provided on one end, and hook engaging structures are provided to the other end and to the middle portion. 
         [0022]    As shown in  FIGS. 1 and 2 , a grommet  100  is provided at each of the front end portion, the middle portion, and the rear end portion of two battery modules  11 . 
         [0023]    As shown in  FIG. 3 , when several battery modules  11  are loaded in a battery holder  12 , the grommets  100  maintain equal spacing between each battery module  11 . 
         [0024]    Referring to  FIG. 4 , in which (a) shows a state before coupling portions  110  and  120  are assembled with each other, and (b) shows a state after the coupling portions  110  and  120  are assembled with each other, the grommet  100  comprises two coupling portions  110  and  120  connected to each other by a hinge portion  121  (not depicted in  FIG. 4 ). The coupling portions  110  and  120  form two circular battery module receiving portions  111  when assembled. 
         [0025]    Referring to  FIGS. 5-8 , the hinge portion  121  is shown. Especially as shown in  FIG. 6 , the hinge portion  121  has relatively thick ends, indicated at d 1 , and a thinner center, indicated at d 2 . This structure ensures maximum flexibility in the center of the hinge portion  121 , where the maximum bending occurs. For example, d 1  may be about 0.7 mm and d 2  may be about 0.3 mm. 
         [0026]    The two coupling portions  110  and  120  are connected only at the hinge portion  121 . End surfaces  112  and  122  of the two coupling portions  110  and  120  are divided from each other, such as by the inclined shapes shown, to facilitate rotation of the coupling portions  110  and  120  when being opened, and there may be a gap, e.g., 0.2 mm, between the end surfaces  112  and  122 . 
         [0027]    Referring to  FIG. 5 , cut portions  113  and  123  are provided on the ends of the coupling portions  110  and  120  such that both ends of the hinge portion  121  are separated from the end portions of the coupling portions  110  and  120 , ensuring sufficient length of the hinge portion  121  to facilitate bending. 
         [0028]    Referring to  FIGS. 9-11 , two fixing hooks  114  protrude from the middle portion of one of the coupling portions  110 , and two hook engaging projections  125 , with which the fixing hooks  114  are engaged, are provided on the other coupling portion  120 . The fixing hooks  114  are inserted into rectangular holes  124  in the coupling portion  120 , and are engaged with the hook engaging projections  125  on the inner walls of the holes  124 . 
         [0029]    Referring to  FIG. 10 , during assembly, when the fixing hooks  114  are inserted into the holes  124 , inclined surfaces  114   a  and  125   a  on the fixing hook  114  and the hole  124 , respectively, are in contact with each other such that the fixing hooks  114  are pushed inwardly and, then, the two fixing hooks return outward to their original positions by the elastic force thereof and are engaged with the hook engaging projections  125 . 
         [0030]    The fixation strength of the hooks  114  is high without any externally protruding portions and thus it is possible to prevent the separation of the grommet  100  and increase the fixation strength of the battery modules. Preferably, a hook reinforcing rib  115  ( FIG. 10 ) protrudes from the inner wall of the fixing hook  114  such that the fixing hook  114  is more firmly engaged with the hook engaging projection  125 . As a result, the fixation strength is higher yet. 
         [0031]    Referring to  FIGS. 12-15 , a fixing hook  126  protrudes from the middle portion of one of the coupling portions  120 , and a hook engaging projection  116  ( FIGS. 13 and 15 ), with which the fixing hook  126  is engaged, is provided on the other coupling portion  110 . 
         [0032]    As shown in  FIG. 12 , since the end portions positioned opposite the hinge portion  121  are thin, the hook engaging structure is provided above the center of the grommet  100 . That is, the fixing hook  126  protrudes upward, and the hook engaging projection  116  is disposed high on the upper coupling portion  110 , providing a stable hook engaging structure. 
         [0033]    Preferably, an engaging surface  126   a  of the fixing hook  126  and an engaging surface  116   a  of the hook engaging projection  116  are tapered to increase the engaging force and prevent the separation of the fixing hook  126 . For example, as shown in  FIG. 13 , the engaging surfaces  126   a  and  116   a  each has a reverse taper angle of about 5°. 
         [0034]    As described above, the grommet for coupling battery modules in accordance with the present invention is composed of a single component, in which two coupling portions are connected by a hinge portion. Moreover, with superior hook engaging structures at the middle and ends of the coupling portions, the coupling portions are firmly connected to each other. Accordingly, separation of the grommet is prevented. Moreover, the manufacturing cost is reduced by a reduction in the number of components. 
         [0035]    The invention has been described in detail with reference to preferred embodiments thereof. However, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.