Abstract:
A battery housing for a traction motor battery of a vehicle is disclosed that includes attachments retained by parallel T-shaped guides on the outer surface of the walls of the enclosure. The attachments are oriented to extend either in a horizontal orientation or vertical orientation. The depth of the attachments and shape of the attachments may be selected to meet impact force requirements and packaging space limitations imposed by the structure of the vehicle.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a division of U.S. application Ser. No. 14/619,205 filed Feb. 11, 2015, the disclosure of which is hereby incorporated in its entirety by reference herein. 
     
    
     TECHNICAL FIELD 
       [0002]    This disclosure relates to protective structures for battery enclosures for electric vehicle batteries. 
       BACKGROUND 
       [0003]    Electric vehicles use batteries that are enclosed in an enclosure or housing that is assembled to the vehicle body. The battery may be assembled to the vehicle body at a location that is spaced from the front, rear and sides of the vehicle. For example, the battery may be assembled below the passenger compartment, in the trunk, in front of the passenger compartment or in a longitudinally extending tunnel. 
         [0004]    The battery must be protected from damage in a collision. The battery housing may be tightly packed with lithium ion battery packs or other types of battery cells. Deformation of the battery housing is to be avoided to prevent intrusion of the housing into the area housing the battery cells. Intrusions into the battery housing may rupture of battery cells and spill the contents of the battery cells. 
         [0005]    When the battery housing is assembled in a central location in the vehicle, e.g. beneath the passenger compartment, limited crush space is available between the side of the vehicle body and the battery enclosure. More crush space is available between the battery enclosure and the front or rear ends of the vehicle. In either situation, there is a long felt and unfulfilled need for an efficient and effective lightweight structure for absorbing energy from a collision that minimizes battery enclosure deformation. The structure must have limited package space requirements while providing added stiffness to the battery enclosure assembly including the impact absorbing structure. 
         [0006]    Some approaches to protecting the battery enclosure have proposed adding beams and cross members on the battery enclosure or extending outboard of the battery enclosure. These approaches add weight to the vehicle and require additional space to package the beams and cross members. Added weight is to be avoided because added weight adversely affects fuel economy. Increasing packaging space requirements adversely affects vehicle design freedom. 
         [0007]    The above problems and other problems are addressed by this disclosure as summarized below. 
       SUMMARY 
       [0008]    According to one aspect of this disclosure, a housing is disclosed for a traction motor battery of a vehicle. The housing includes a plurality of side walls, a top wall and a bottom wall. Each of the walls includes a plurality of parallel T-shaped guides. The T-shaped guides on the top wall and on the bottom wall extend horizontally and the T-shaped guides on some of the side walls extend vertically. The housing also includes a plurality of elongated attachments assembled between the T-shaped guides. 
         [0009]    According to other aspects of this disclosure, the T-shaped guides may include a pair of cantilevered flanges and a spacing leg that extends from each of the walls to a juncture of the pair of cantilevered flanges. The attachments may include edge portions that have a thickness that is substantially equal to the length of the spacing leg. 
         [0010]    The attachments may include a first edge portion and a second edge portions that are adapted to be received by a pair of parallel T-shaped guides. The attachments may also include a central portion between the first edge portion and the second edge portion that is co-planar with the edge portions. The attachments may include a central portion between the first edge portion and the second edge portion that includes a partially cylindrical wall that protrudes outwardly from the T-shaped guides and connects the first edge portion and the second edge portion. Alternatively, the attachments may include a central portion between the first edge portion and the second edge portion that includes an impact receiving outer face and supporting walls that extend between the central portion and the edge portions. 
         [0011]    The attachments may include a first embodiment including a first central portion between the first edge portion and the second edge portion that includes a first impact receiving outer face and a first pair of supporting walls that extend a depth “D” between the first central portion and the first and second edge portions, and a second embodiment including a second central portion between a third edge portion and a fourth edge portion including a second central portion between the third edge portion and the fourth edge portion that includes a second impact receiving outer face and supporting walls that extend a depth “D” between a second central portion and the third and fourth edge portions, wherein the depth “D” is greater than the depth “d.” 
         [0012]    According to another aspect of this disclosure, the plurality of attachments may include different first and second sets of attachments. The first set of attachments may have a depth “D” measured from the respective wall to an impact receiving surface of the attachment in a direction normal to the wall. The second set of attachments may have a depth “d” measured from the respective wall to an impact receiving surface of the attachment in a direction normal to the wall, wherein the depth “D” is greater than the depth “d.” The attachments may also include a third set of attachments having a depth “d1” measured from the respective wall to an impact receiving surface of the attachment in a direction normal to the wall, wherein the depth “d” is greater than the depth “d1.” 
         [0013]    The attachments may include different types of attachments. A first type of attachment may be provided that has a first central portion between a first edge portion and a second edge portion, wherein the first central portion is partially cylindrical. A second type of attachment may have a second central portion between a third edge portion and a fourth edge portion, wherein the second central portion includes a planar impact receiving outer face. The second type of attachment may include first and second supporting walls that extend between the second central portion and the third and fourth edge portions. Alternatively, the planar impact receiving outer face may be provided on an outer side of a planar reinforcement plate. 
         [0014]    According to another aspect of this disclosure, method is disclosed for providing an impact absorbing enclosure for a battery of a vehicle having a battery powered traction motor. The method comprises providing vertically extending walls that have a plurality of parallel vertical guides providing a plurality of attachments and inserting the attachments between the vertical guides to provide the vertically extending walls with an impact absorbing assembly formed by of the attachments on an outer surface of the vertically extending walls. 
         [0015]    According to other aspects of this disclosure as it relates to the method, the method may further comprise providing horizontally extending walls that having a plurality of parallel horizontally extending guides. Providing a plurality of second attachments and inserting the second attachments between the horizontally extending guides to provide the horizontally extending walls with impact absorbing assembly formed by the second attachments on a second outer surface of the horizontally extending walls. 
         [0016]    According to other alternative aspects of this disclosure the vertically extending guides on the vertical walls may be T-shaped guides and the horizontally extending guides on the horizontal walls may be T-shaped guides. The T-shaped guides may include a spacing leg and a pair of cantilevered flanges, wherein the spacing leg extends from each of the walls to a juncture of the pair of cantilevered flanges. The attachments may include edge portions that have a thickness that is substantially equal to the length of the spacing leg. 
         [0017]    According to other aspects of this disclosure, a peripheral space may be defined by the vehicle around the impact absorbing enclosure that is available for inserting the attachments includes small areas and large areas. The method may further include: a first additional step of selecting a first set of attachments having a depth “D” measured from the respective wall to an impact receiving surface of the attachment in a direction normal to the wall, and inserting the first set of attachments in the large areas; and a second additional step of selecting a second set of attachments having a depth “d” measured from the respective wall to an impact receiving surface of the attachment in a direction normal to the wall, and inserting the second set of attachments in the small areas, wherein the depth “D” is greater than the depth “d.” 
         [0018]    The method may also relate to a peripheral space defined by the vehicle around the impact absorbing enclosure that is available for inserting the attachments includes a first area having a first configuration and a second area having a second configuration. The method may include the use of a first type of attachment having a partially cylindrical first central portion between a first edge portion and a second edge portion. The method may further include the use of a second type of attachment having a planar second central portion between a third edge portion and a fourth edge portion, wherein the first area is provided with the first type of attachment and the second area is provided with a second type of attachment. 
         [0019]    The above aspects of this disclosure and other aspects are described below with reference to the attached drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a diagrammatic bottom plan view of a vehicle illustrating a battery enclosure disposed on the vehicle frame beneath the passenger compartment. 
           [0021]      FIG. 2  is a perspective view of a first embodiment of a battery enclosure including several different types of attachments provided on the sides and top of the enclosure. 
           [0022]      FIG. 3  is a fragmentary enlarged perspective view of a portion of the battery enclosure illustrated in  FIG. 2 . 
           [0023]      FIG. 4  is a fragmentary enlarged cross-sectional view of a portion of the battery enclosure illustrated in  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    The illustrated embodiments are disclosed with reference to the drawings. However, it is to be understood that the disclosed embodiments are intended to be merely examples that may be embodied in various and alternative forms. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed are not to be interpreted as limiting, but as a representative basis for teaching one skilled in the art how to practice the disclosed concepts. 
         [0025]    Referring to  FIG. 1 , a vehicle  10  is diagrammatically illustrated with a battery  12  for a battery-powered traction motor. The vehicle  10  includes a body  14  that is supported on a frame  16 . A traction motor  18  is also assembled to the frame  16 . The traction motor  18  is a battery-powered traction motor that is powered by the battery  12  to drive the wheels  20 . This disclosure focuses on the enclosure  21  for the battery. 
         [0026]    The body  14  includes a side body  22 , a front bumper  24  and a rear bumper  26 . The battery  12  in the enclosure  21  is shown to be centrally located underneath the passenger compartment of the vehicle  10 . It should be noted that there is a substantially greater amount of space between the battery and the front and rear bumper  24  and  26  compared to the relatively closer spacing of the side body  22  to the battery  12 . Side impact collisions that result in driving the side body  22  toward the battery  12  present a greater challenge when designing attachments for the battery  12  due to the reduced amount of crush space available between the side body  22  and the battery  12 . 
         [0027]    Referring to  FIGS. 2-4 , the enclosure, generally indicated by reference numeral  21 , is shown to include a bottom wall  30  (shown in  FIG. 1 ) and a top wall  32 . A front wall  36  faces the front bumper  24  (shown in  FIG. 1 ) and a rear wall  38  faces the rear bumper  26  (shown in  FIG. 1 ). The battery enclosure  21  includes a right side wall  40  and a left side wall  42 . The side walls are joined at corners  44 . 
         [0028]    In the illustrated embodiments three different types of attachments are shown but it should be understood that other configurations and shapes of attachments may be utilized depending in part on the space available within the vehicle. The three types of attachments illustrated include a partially cylindrical attachment  48 , a trapezoidal space defining attachment  50  and a planar attachment  52 . 
         [0029]    The impact absorbing wall  54  of the semi-cylindrical attachment  48  as illustrated in  FIGS. 2 and 3  is an arcuate, or semi-cylindrical, wall  54  that forms a semi-cylindrical pocket  56  with the planar wall of the enclosure  21 . The impact absorbing wall  48  is an arcuate shaped elongated member with the arc of the wall being generated about a horizontal axis X when the partially cylindrical attachment  48  is mounted in a horizontal orientation when the partially cylindrical attachment  48  is attached to a top wall  32  or a bottom wall  30  or a vertical axis Y when attached to a vertical wall  36 - 42 . The attachments may also be secured in a horizontal orientation on one or more of the vertical walls. Attachment flanges  58  and  60  are provided on opposite edges of the semi-cylindrical impact absorbing wall. 
         [0030]    The trapezoidal space defining attachment  50  defines a trapezoidal pocket  62 . The attachment  50  includes a spaced wall, or impact absorbing wall  64 , a right ramp wall  66  and a left ramp wall  68  on opposite sides of the impact absorbing wall  64 . The right ramp wall  66  and the left ramp wall  68  extend to right and left attachment flanges  72  and  74 , respectively. As shown the ramp walls  66  and  68  are disposed at about a 45° angle relative to the wall of the enclosure. It should be understood that the orientation of the ramp surfaces could be at any angle or even at a right angle to the wall of the enclosure. 
         [0031]    The planar attachment  52  is a planar member that is attached to one of the walls on the enclosure  21 . The planar attachment  52  has a right edge  76  and a left edge  78  that function as attachment flanges. 
         [0032]    The attachments  48 - 52  are attached to the walls of the enclosure by T-shaped guides  80  that are provided on the enclosure in a parallel orientation. The attachment flanges  58  and  60  of the semi-cylindrical attachment, right and left flanges  72  and  74  of the trapezoidal attachment  50  and edges  76  and  78  are adapted to be received by adjacent T-shaped guides  80  that hold the attachments against the enclosure  21 . The T-shaped guides include a central flange  82  that is attached to a wall on an inner end and extends outwardly to a crossbar  84 . The cross-bar  84  is parallel to the wall of the enclosure to which the T-shaped guide  80  is attached. Generally, one T-shaped guide supports two attachments except at a corner where only one attachment flange requires support. 
         [0033]    Referring to  FIG. 4 , the different styles of attachments each have a different depth as measured from the walls and require more or less space. For example, in  FIG. 4  the semi-cylindrical attachment  48  is shown to have a depth “D” and the trapezoidal attachment  50  has a depth “d.” Depth “d” is less than depth “D” and would require less packaging space around the enclosure. The depth of the planar attachment is equal to the thickness of the planar attachment  52  and would be less than the depth “d” and would require even less space. 
         [0034]    The ability of the respective attachments to absorb impact energy also varies depending upon the type of attachment. The attachments may be fabricated to have different thicknesses and may be made of different materials including aluminum alloys, steel alloys, fiber reinforced composites or polymers compositions. This disclosure enables the battery enclosure  21  to resist a wide range of impact forces while being accommodated within the packaging space available around the enclosure  21 . Other vehicle components are generally indicated by structure  86  shown in  FIG. 4 . The other structure may be frame rails, beams, floor structure, accessories, or the like. 
         [0035]    The T-shaped guides  80  provide a flexible mechanism for supporting the attachments on the enclosure  21 . Changes in the design of a vehicle may impact the space available for the impact absorbing attachments. If there is a reduction in the space available as a result of a design change, a trapezoidal attachment may be substituted for a semi-cylindrical attachment. If a test indicates that additional impact energy absorption is needed on a side or part of one of the sides, stronger or thick attachments may be used or a different style of attachment may be specified. 
         [0036]    The embodiments described above are specific examples that do not describe all possible forms of the disclosure. The features of the illustrated embodiments may be combined to form further embodiments of the disclosed concepts. The words used in the specification are words of description rather than limitation. The scope of the following claims is broader than the specifically disclosed embodiments and also includes modifications of the illustrated embodiments.