Abstract:
A battery module ( 10 ) for a motor vehicle has at least one battery cell ( 12 ) for producing and storing electrical energy and a rigid battery frame ( 14 ) in which the at least one battery cell ( 12 ) is accommodated. An absorption element ( 24 ) is secured to the battery frame ( 14 ) by connection sections ( 28 ). The absorption element ( 24 ) is spaced apart from the battery frame ( 14 ) in such a way that a cavity ( 26 ) is formed between the absorption element ( 24 ) and the battery frame ( 14 ).

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to a battery module for a motor vehicle. The invention further relates to a motor vehicle drive train comprising an electrical machine for providing drive power and comprising a battery module for providing electrical energy for the electrical machine. 
         [0003]    2. Description of the Related Art 
         [0004]    In the field of motor vehicle engineering, it is generally known to use electrical energy stores in order to supply electrical energy to the motor vehicle, for example for the purpose of driving a drive machine. Energy stores of this kind usually are accommodated in a stable battery housing for the purpose of protecting against damage. Damage can occur to the electrical energy store under high acceleration forces or deformation of the body of the motor vehicle, for example in the event of the motor vehicle being subject to an impact. Since damage to the electrical energy store of this kind, particularly in the case of powerful traction batteries, presents a high risk potential for occupants of the motor vehicle and other persons, the electrical energy store in the motor vehicle has to have special apparatuses to protect against damage. 
         [0005]    DE 10 2009 053 138 A1 discloses an energy absorption apparatus for the purpose of protecting an electrical energy store of a motor vehicle, in which energy absorption apparatus the electrical energy store is provided with associated energy absorption elements which serve to absorb deformation energy in the event of the vehicle being subject to an impact and as a result protecting the battery against damage. One disadvantage of this is that the energy absorption elements are complicated to manufacture and, in the event of an impact, not all of the deformation energy can be absorbed by the absorption elements, so that a mechanical force is exerted on the energy store and can lead to damage. 
         [0006]    The object of the invention is therefore to provide a battery module for a motor vehicle, in which battery module an electrical energy store is protected against damage with a low level of technical complexity. 
       SUMMARY 
       [0007]    The invention relates to a battery module for a motor vehicle, comprising at least one battery cell for providing and storing electrical energy, a rigid battery frame in which the at least one battery cell is accommodated, and an absorption element that is fixed to the battery frame by fixing sections. The battery module is configured so that the absorption element is kept at a distance from the battery frame, and so that a hollow space is formed between the absorption element and the battery frame. 
         [0008]    The motor vehicle drive train of the invention is configured so that the battery module is a battery module according to the invention. 
         [0009]    The absorption element is kept at a distance from the battery frame. Thus, a deformation zone can be formed between the battery frame and the absorption element, so that, in the event of the motor vehicle being subject to an impact, the absorption element can initially absorb deformation energy without mechanical force being exerted on the battery frame and the battery cell that is accommodated in the battery frame. As a result, the battery cell can be protected against damage in an effective manner and with a low level of technical complexity in this way. 
         [0010]    In one embodiment, the absorption element is in the form of a panel that, at its ends, is fixed to the battery frame. In this way, the absorption element can be produced and fitted with a low level of technical complexity. 
         [0011]    The battery frame may have an external panel that faces the absorption element. In this way, the battery cell can be protected further against deformation of the absorption element. 
         [0012]    The hollow space may be formed between the external panel and the absorption element. In this way, a defined hollow space can be formed as a deformation zone between the absorption element and the frame. 
         [0013]    The battery module in one embodiment has a battery housing in which the battery frame is accommodated. Thus the absorption element is fixed to the battery housing. In this way, the stability of the battery housing can be increased since the battery housing is supported on the absorption element. 
         [0014]    The absorption element may be fixed to the battery housing by screw elements. In this way, the absorption element can be fixed in the battery housing with a low level of fitting complexity. 
         [0015]    An absorption element may be formed on each of the opposite sides of the battery frame. In this way, the battery cell can be protected on opposite sides against deformation which can occur, for example, when the motor vehicle is rammed. 
         [0016]    The absorption element may be formed in front of or behind the at least one battery cell in a direction of travel of the motor vehicle. In this way, impact energy of the motor vehicle can be absorbed by the absorption element for different impact situations. 
         [0017]    The absorption element may have a plurality of connecting sections on opposite sides. The connecting sections may be fixed to the battery frame. In this way, a stable connection can be formed between the battery frame and the absorption element. 
         [0018]    The absorption element may be formed integrally with the connecting sections. In this way, the absorption element and the connecting sections can be manufactured with a low level of technical complexity. 
         [0019]    The absorption element of one embodiment is formed from stainless steel. In this way, an absorption element which is particularly rigid and can absorb a large amount of deformation energy can be provided. 
         [0020]    Overall, the battery module according to the invention can provide effective protection for the battery cell since the absorption element can absorb deformation energy in the event of the motor vehicle being subject to an impact and can deform by the distance of the absorption element from the battery frame, without damaging the battery cell. 
         [0021]    The features mentioned above and those still to be explained below can be used not only in the respectively indicated combination, but also in other combinations or on their own without departing from the scope of the present invention. 
         [0022]    Exemplary embodiments of the invention are illustrated in the drawing and will be explained in greater detail in the following description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  shows a schematic side view of a battery module comprising an absorption element. 
           [0024]      FIG. 2  shows a perspective partial view of a battery module comprising an absorption element and a battery housing. 
           [0025]      FIG. 3  shows a perspective view of a battery module comprising a plurality of battery cells and opposite absorption elements. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]      FIG. 1  shows a schematic sectional view of a battery module which is designated  10  in general. The battery module  10  has a plurality of battery cells  12  that are accommodated in a battery frame  14  and are mounted in the battery frame  14 . The battery cells serve to store electrical energy and to provide stored electrical energy and are electrically connected to one another by means of busbars  16 . The battery frame  14  is accommodated or mounted in a battery housing  18 . The battery housing  18  has a housing frame  20  that has a double-walled structure with transverse struts  22  to mechanically reinforce the housing frame  20 . 
         [0027]    An absorption element  24  is in the form of a flat panel that is kept at a distance from the battery frame  14  and is fixed to the battery frame  14 . A hollow space  26  is formed between the absorption element  24  and the battery frame  14 . The absorption element  24  has connecting sections  28  on each of the opposite sides. The connecting sections are fixed to the battery frame  14  to establish a distance between the absorption element  24  and the battery frame  14 . The connecting sections  28  preferably are formed integrally with the absorption element  24  and fixed to the battery frame  14 . In a particular embodiment, the connecting sections  28  can also be separate spacers  28  that establish a distance between the flat absorption element  24  and the battery frame  14 . The absorption element  24  is kept at a distance of greater than 3.5 mm from the battery frame  14 , so that the hollow space  26  is formed with a size of greater than 3.5 mm. 
         [0028]    The battery housing  18  generally is screwed fixedly to the absorption element  24  by screw elements  30 , so that the battery housing  18  can be supported on the absorption element  24  and in this way the stability of the housing frame  20  can accordingly be increased. 
         [0029]    Since the absorption element  24  is kept at a distance from the battery frame  14 , a deformation space can be formed, so that the absorption element  24  can be deformed in the event of the motor vehicle being subject to an impact, without the battery cells  12  having to absorb mechanical energy and accordingly not being damaged. 
         [0030]    The absorption element  24  preferably is arranged on the battery frame  14  as an end panel. More particularly, the battery frame  14  has an external panel on a side that faces the absorption element  24  in order to increase the stability of the battery frame  14 . Accordingly, the hollow space  26  is formed between the external panel  32  of the battery frame  14  and the absorption element  24 . 
         [0031]    When the battery module  10  is in the installed state, the absorption element  24  is arranged in a direction of travel of the motor vehicle, sas indicated by an arrow  34  in  FIG. 1 . In this way, the impact energy can be absorbed by the absorption element  24  in an effective manner in the event of the motor vehicle being subject to an impact. 
         [0032]      FIG. 2  is a perspective illustration of a schematic partial view of the battery module  10 . Identical elements are provided with the same reference numerals, with only the special features being explained here. 
         [0033]    The battery frame  14  is formed from individual segments  36  that extend in a vertical direction of the battery module  10 . The battery frame  14  has the external panel  32  on an end face of the battery arrangement  10 , and the absorber element  24  is fixed to the battery frame  14  at a distance from the external panel  32 . The absorber element  24  is in the form of a metal panel and is preferably manufactured from stainless steel. The metal panel has the connecting sections  28  on each of the opposite longitudinal sides, with the connecting sections being fixed to the battery frame  14 , for example by welded connections. The connecting sections  28  are bent sections of the metal panel that forms the absorber element  24  and are connected integrally to the metal panel. The metal panel that forms the absorber element  24  is arranged at a distance from the battery frame  14  or the external panel  32  by means of the connecting sections  28 , so that the hollow space  26  is formed as a deformation zone between the two panels. The housing frame  20  is fixed or fixedly screwed to the absorber element  24  by means of the screw elements  30 . The screw elements  30  are recessed into recesses  38  in the housing frame  20 . 
         [0034]    Since the housing frame  20  is fixed to the absorber element and the absorber element  24  is kept at a distance from the battery frame  14  by means of the connecting sections  28 , the housing frame  20  and the absorber element  24  can absorb deformation energy without the battery frame  14  and the battery cell  12  accommodated in the battery frame being damaged. Deformation energy can be absorbed by deformation of the absorber element  24  in the direction of the battery frame  14 . Deformation corresponding to the distance between the absorber element  24  and the battery frame  14  of at least 3.5 mm is possible without damaging the battery cell  12 . 
         [0035]      FIG. 3  is a schematic perspective view of the battery module  10 . Identical elements are provided with the same reference numerals, with only the special features being explained here. 
         [0036]    The battery arrangement  10  has an absorber element  24  on each of the two opposite end faces. The absorber element is fixed to the battery frame  14  in the manner described above. The absorber elements  24  are fixed respectively to end faces of the battery frame  14 , specifically in front of and behind the battery frame  14  in the direction  34  of travel of the motor vehicle in order to accordingly absorb the kinetic energy or the deformation energy of the motor vehicle in the event of an impact. Each absorber element is arranged at a distance of greater than 3.5 mm from the battery frame  14  or the external panel  32 , so that a deformation zone of more than 7 mm is formed by the two opposite absorber elements  24  overall. 
         [0037]    The absorber element  24  and the deformation zone formed by the hollow space  26  enables the battery cells  12  to be protected against damage in an effective manner in the event of the motor vehicle being subject to an impact.