Patent Publication Number: US-2022223962-A1

Title: Rigid linkages for battery packs

Description:
TECHNICAL FIELD 
     This disclosure relates generally to electrified vehicles, and more particularly to rigid linkages designed to allow a traction battery pack to articulate away from a deforming vehicle structure. 
     BACKGROUND 
     Some electrified vehicles include a traction battery pack packaged at underbody locations of the vehicle. At these locations, the traction battery pack may be positioned near deformable structures. 
     SUMMARY 
     An electrified vehicle according to an exemplary aspect of the present disclosure includes, among other things, a frame including a cross-member, a traction battery pack, and a rigid linkage that connects between the cross-member and the traction battery pack. The rigid linkage is configured to articulate the traction battery pack away from a deforming structure of the frame. 
     In a further non-limiting embodiment of the foregoing electrified vehicle, the frame includes a rocker and a longitudinal member, and the traction battery pack is mounted axially between the rocker and the longitudinal member. 
     In a further non-limiting embodiment of either of the foregoing electrified vehicles, the cross-member is a seat cross-member that extends between the rocker and the longitudinal member. 
     In a further non-limiting embodiment of any of the foregoing electrified vehicles, a mounting bracket connects between the traction battery pack and the longitudinal member. 
     In a further non-limiting embodiment of any of the foregoing electrified vehicles, the rigid linkage, the cross-member, the mounting bracket, and the traction battery pack establish a four-bar linkage for supporting the traction battery pack relative to the frame. 
     In a further non-limiting embodiment of any of the foregoing electrified vehicles, the rigid linkage includes a first mount section mounted to the cross-member, a second mount section mounted to the traction battery pack, and a curved bridge section extending between the first mount section and the second mount section. 
     In a further non-limiting embodiment of any of the foregoing electrified vehicles, a fastener is received through the first mount section and the cross-member. 
     In a further non-limiting embodiment of any of the foregoing electrified vehicles, the fastener further extends through a floor panel of the frame. 
     In a further non-limiting embodiment of any of the foregoing electrified vehicles, the rigid linkage is comprised of a boron steel, the cross-member is comprised of a dual phase steel, and the floor panel is comprised of a mild steel. 
     In a further non-limiting embodiment of any of the foregoing electrified vehicles, the rigid linkage is made of high strength low alloy material, and the cross-member is made of a different material than the rigid linkage. 
     In a further non-limiting embodiment of any of the foregoing electrified vehicles, a mounting bracket that connects between the traction battery pack and a longitudinal member of the frame establishes a pivot point for pivoting the traction battery pack as the traction battery pack articulates away from the deforming structure. 
     In a further non-limiting embodiment of any of the foregoing electrified vehicles, the deforming structure is a floor panel of the frame. 
     In a further non-limiting embodiment of any of the foregoing electrified vehicles, the rigid linkage maintains a gap between a cover of the traction battery pack and the cross-member. 
     A method according to another exemplary aspect of the present disclosure includes, among other things, mounting a traction battery pack to a vehicle frame with a rigid linkage, and articulating a portion of the traction battery pack connected to the rigid linkage away from a deforming structure of the vehicle frame. 
     In a further non-limiting embodiment of the foregoing method, mounting the traction battery pack includes bolting the rigid linkage to a seat-cross member of the vehicle frame. 
     In a further non-limiting embodiment of either of the foregoing methods, mounting the traction battery pack includes mounting the traction battery pack to a longitudinal member of the vehicle frame with a mounting bracket. 
     In a further non-limiting embodiment of any of the foregoing methods, as the portion of the traction battery pack articulates, the traction battery pack pivots at a pivot point established by the mounting bracket. 
     In a further non-limiting embodiment of any of the foregoing methods, the rigid linkage, the seat cross-member, the mounting bracket, and the traction battery pack establish a four-bar linkage for supporting the traction battery pack relative to the vehicle frame. 
     In a further non-limiting embodiment of any of the foregoing methods, the rigid linkage is made of a boron steel. 
     In a further non-limiting embodiment of any of the foregoing methods, the deforming structure is a floor panel of the frame. 
     The embodiments, examples, and alternatives of the preceding paragraphs, the claims, or the following description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible. 
     The various features and advantages of this disclosure will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically illustrates an electrified vehicle. 
         FIG. 2  illustrates select portions of an underside of the electrified vehicle of  FIG. 1 . 
         FIG. 3  is a top view of the vehicle underside of  FIG. 2 . 
         FIG. 4  illustrates an exemplary mounting configuration between multiple vehicle components. 
         FIGS. 5A, 5B, and 5C  illustrate the rigid linkage as part of the traction battery pack mounting system from various different vantage points. 
         FIG. 6  schematically illustrates a first configuration of a vehicle frame mounted traction battery pack. 
         FIG. 7  schematically illustrates a second configuration of the vehicle frame mounted traction battery pack of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
     This disclosure details rigid linkages for mounting traction battery packs to portions of a vehicle frame. The rigid linkages are designed to allow the traction battery pack to articulate away from deforming structures of the vehicle frame as part of an energy distribution system. During the articulation, the rigid linkage is capable of conserving its integrity to push the traction battery pack away from the deforming structures, thereby preventing the deforming structures from contacting the traction battery pack. These and other features are discussed in greater detail in the following paragraphs of this detailed description. 
       FIG. 1  schematically illustrates an electrified vehicle  10 . The electrified vehicle  10  could be a car, a truck, a van, a sport utility vehicle, a crossover, or any other type of vehicle that includes an electrified powertrain. In an embodiment, the electrified vehicle  10  is a battery electric vehicle (BEV). However, the concepts described herein are not limited to BEVs and could extend to other electrified vehicles, including, but not limited to, hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles, etc. Therefore, although not specifically shown in this embodiment, the electrified vehicle  10  could be equipped with an internal combustion engine that can be employed either alone or in combination with other energy sources to propel the electrified vehicle  10 . 
     Although a specific component relationship is illustrated in the figures of this disclosure, the illustrations are not intended to limit this disclosure. The placement and orientation of the various components of the electrified vehicle  10  are shown schematically and could vary within the scope of this disclosure. In addition, the various figures accompanying this disclosure are not necessarily drawn to scale, and some features may be exaggerated or minimized to emphasize certain details of a particular component. 
     In the illustrated embodiment, the electrified vehicle  10  is a full electric vehicle propelled solely through electric power, such as by one or more electric machines  12 , without any assistance from an internal combustion engine. The electric machine  12  may operate as an electric motor, an electric generator, or both. The electric machine  12  receives electrical power and provides a rotational output torque to one or more drive wheels  14  of the electrified vehicle  10 . 
     A voltage bus  16  electrically connects the electric machine  12  to a traction battery pack  18 . The traction battery pack  18  is an exemplary electrified vehicle battery. The traction battery pack  18  may be a high voltage traction battery pack that includes a plurality of battery arrays  20  (i.e., battery assemblies or groupings of rechargeable battery cells) capable of outputting electrical power to operate the electric machine  12  and/or other electrical loads of the electrified vehicle  10 . Other types of energy storage devices and/or output devices can also be used to electrically power the electrified vehicle  10 . 
     The battery arrays  20  may be housed inside an enclosure assembly  22  of the traction battery pack  18 . The enclosure assembly  22  may be sealed enclosure of any size, shape, and configuration and may, in an embodiment, include a tray  24  and a cover  26 . 
     The electrified vehicle  10  may include a passenger cabin  28  and a cargo space  30  (e.g., a trunk, truck bed, etc.) located to the rear of the passenger cabin  28 . A floor panel  32  may separate the passenger cabin  28  from other potions of a vehicle frame  34 , which generally establishes a vehicle underbody  36 . In an embodiment, the traction battery pack  18  is suspended from or otherwise mounted to the vehicle frame  34  such that it is remote from both the passenger cabin  28  and the cargo space  30 . The traction battery pack  18  therefore does not occupy space that would otherwise be available for carrying passengers or cargo. 
     Due at least in part to its mounting location at the underbody  36 , the traction battery pack  18  may be susceptible to various vehicle loads including, but not limited to, impact loads (e.g., loads imparted during vehicle impact and running clearance events, for example), durability loads, and inertial loads. If not accommodated for, these loads could be transferred directly into the traction battery pack  18 . This disclosure is therefore directed to mounting systems with rigid linkages designed for distributing energy to minimize or even prevent the transfer of the loads into the traction battery pack  18 . 
       FIGS. 2-3  illustrate an exemplary packaging location of the traction battery pack  18  at the underbody  36  of the vehicle frame  34 . The vehicle frame  34  (sometimes referred to simply as a “frame”) is the main supporting structure of the electrified vehicle  10 , to which various components are attached, either directly or indirectly. The vehicle frame  34  may include a unibody construction, in which the chassis and body of the electrified vehicle are integrated into one another, or may be part of a body-on-frame construction. 
     The vehicle frame  34  may include one or more longitudinal members  38 , e.g. tunnel runners, that extend along a length of the electrified vehicle  10  and one or more cross-members  40  that extend across a width of the vehicle. The vehicle frame  34  may further include a rocker  42  that extends adjacent to one longitudinal side surface  44  of the traction battery pack  18 . The rocker  42  forms a beam/frame member that extends along a side of the vehicle between the front and rear doors. 
     One or more seat cross-members  46  of the vehicle frame  34  may extend between the rocker  42  and one of the longitudinal members  38 . The seat cross-members  46  may support a seat positioned within the passenger cabin  28 . The floor panel  32  of the vehicle frame  34  extends over top of all or portions of the longitudinal member  38 , the cross member  40 , the rocker  42 , and the seat-cross member  46 . 
     In an embodiment, the traction battery pack  18  is mounted axially between the rocker  42  and the longitudinal member  38 . In the illustrated embodiment, the traction battery pack  18  is mounted adjacent to the rocker  42  associated with a passenger side of the electrified vehicle  10 . However, the traction battery pack  18  could alternatively be mounted adjacent to a rocker associated with a driver side of the electrified vehicle  10 . In the mounted position, the cover  26  of the traction battery pack  18  faces toward the floor panel  32  and the tray  24  of the traction battery pack  18  faces toward the ground. 
     The traction battery pack  18  may be mounted such that a gap extends between the cover  26  of the enclosure assembly  22  of the traction battery pack  18  and the seat cross-member  46 . The seat cross-member  46  and the floor panel  32  both extend over top of the traction battery pack  18 . 
     A plurality of mounting brackets  48  may be used to mount the traction battery pack  18  to the vehicle frame  34 . In an embodiment, two mounting brackets  48  are used to mount the traction battery pack  18  to the longitudinal member  38 , and another mounting bracket  48  is used to mount the traction battery pack  18  to the cross-member  40 . The mounting brackets  48  may be welded, bolted, or both welded and bolted to the traction battery pack  18  and to the longitudinal member  38  or the cross-member  40 . The total number and configuration of the mounting brackets  48  used to mount the traction battery pack  18  relative to the underbody  36  may vary per vehicle design and is therefore not intended to limit this disclosure. In some embodiments, at least one of the mounting brackets  48  (here, the mounting bracket  48  connected to the cross-member  40 ) may include a different configuration than the other mounting brackets  48 . 
     A rigid linkage  50  may also be used to mount the traction battery pack  18  to the vehicle frame  34 . Together, the mounting brackets  48  and the rigid linkage  50  establish a mounting system for mounting the traction battery pack  18  to the vehicle frame  34 . Although only a single rigid linkage is illustrated in the exemplary embodiment of  FIGS. 2-3 , the mounting system could employ one or more of the rigid linkages  50  within the scope of this disclosure. 
     In an embodiment, the rigid linkage  50  is mounted to the seat cross-member  46  and to the longitudinal side surface  44  of the traction battery pack  18 . In this embodiment, the longitudinal side surface  44  faces in a direction toward the rocker  42 . A majority of the rigid linkage  50  may therefore be positioned between the rocker  42  and the traction battery pack  18 . 
     The rigid linkage  50  may be welded, bolted, or both welded and bolted to the traction battery pack  18  and to the seat cross-member  46 . In an embodiment, the rigid linkage  50  is welded to the longitudinal side surface  44  of the traction battery pack  18  and is bolted to the seat cross-member  46 . However, other configurations are also contemplated. 
     An exemplary mounting configuration of the rigid linkage  50  at the seat cross-member  46  is depicted in  FIG. 4 . The seat cross-member  46  may include two or more mounting tabs  52  that include mounting openings  54 . The mounting openings  54  may align with corresponding mounting openings  56  (see  FIG. 2 ) formed through the rigid linkage  50  for receiving a fastener  59  (e.g., a bolt, screw, etc.). In an embodiment, each fastener  59  is received through each of the rigid linkage  50 , the seat cross-member  46 , and the floor panel  32  for joining these components together. 
       FIGS. 5A, 5B, and 5C , with continued reference to  FIGS. 1-4 , illustrate in greater detail the rigid linkage  50  of the exemplary traction battery pack  18  mounting system. As further detailed below, the rigid linkage  50  is designed to allow the traction battery pack  18  to articulate away from deforming structures (e.g., the floor panel  32 ) of the vehicle frame  34  during certain conditions (e.g., front, side, side pole, rear loads, etc.). 
     The rigid linkage  50  may include a first mount section  58 , a second mount section  60 , and a bridge section  62  extending between the first and second mounting sections  58 ,  60 . Together, the first mount section  58 , the second mount section  60 , and the bridge section  62  establish a monolithic structure having no mechanical fasteners. The first mount section  58  and the second mount section  60  may protrude in opposite directions from the bridge section  62 . Therefore, in an embodiment, the rigid linkage  50  is generally Z-shaped. However, other shapes are also contemplated within the scope of this disclosure. 
     When mounted, the first mount section  58  of the rigid linkage  50  interfaces with the seat cross-member  46 , and the second mount section  60  of the rigid linkage  50  interfaces with the traction battery pack  18 . The mounting openings  56  are formed through the first mount section  58  for bolting the rigid linkage  50  to the seat cross-member  46 . The second mount section  60  may include a edge profile  64  (See  FIG. 5A ) for accommodating a weld bead for welding the second mount section  60  to the traction battery pack  18 . Alternatively, the second mount section  60  could also include mounting openings  66  for bolting the rigid linkage  50  to the enclosure assembly  22  of the traction battery pack  18 . 
     The bridge section  62  may connect at one end of each of the first mount section  58  and the second mount section  60 . In an embodiment, the bridge section  62  is curved between the first and second mount sections  58 ,  60 . 
     One or more ribs  68  may be formed in each of the first mount section  58 , the second mount section  60 , and the bridge section  62 . The ribs  68  are configured to increase the strength and stiffness of the rigid linkage  50 . 
     The rigid linkage  50  may be made of a relatively stiff metallic material. In an embodiment, the rigid linkage is made of a high strength low alloy (HSLA) steel, such as boron steel, for example. Other high strength materials could alternatively be used to manufacture the rigid linkage  50  within the scope of this disclosure. 
     The rigid linkage  50  may be made of a different material compared to the seat cross-member  46  and the floor panel  32 . For example, in an embodiment, the rigid linkage  50  may be made of a boron steel, the seat cross-member  46  may be made of a dual phase steel, and the floor panel  32  may be made of a mild steel. 
       FIGS. 6 and 7 , with continued reference to  FIGS. 2-5C , schematically illustrate a first configuration C 1  and a second configuration C 2 , respectively, of the vehicle frame mounted traction battery pack  18 . In the first configuration C 1  of  FIG. 6 , the traction battery pack  18  is secured to the seat cross-member  46  by both the rigid linkage  50  and one or more mounting brackets  48  of the mounting system. In the exemplary embodiment, the rigid linkage  50  is positioned at an outboard side of the traction battery pack  18  and the mounting bracket  48  is positioned at an inboard side of the traction battery pack  18 . Together, the rigid linkage  50 , the seat cross-member  46 , the mounting bracket  48 , and the traction battery pack  18  may establish a four-bar linkage for supporting the traction battery pack  18  relative to the vehicle frame  34 . 
     Referring now to the second configuration C 2  of  FIG. 7 , the behavior of the mounting system is schematically illustrated during an energy distribution event in which a force F is imparted into the vehicle frame  34 . The vehicle energy distribution event may be the result of a side impact loading event or a side pole impact loading event in which the force F is imparted into a side of the electrified vehicle  10 , for example. 
     During the energy distribution event, the force F is initially absorbed by the floor panel  32  and the seat-cross member  46 , thereby causing one or both of these components to deform downwardly. As the downward deformation occurs, the rigid linkage  50  is capable of conserving its integrity, thereby causing the traction battery pack  18  to articulate away from the impact zone (i.e., in a direction D 1 ) by maintaining a gap G between the traction battery pack  18  and the seat cross-member  46 . The traction battery pack  18  may pivot at a pivot point  70  established by the mounting bracket  48  as the traction battery pack  18  is pushed in the same direction as the deformation by the rigid linkage  50 . The mounting system, and in particular the rigid linkage  50 , therefore establishes a low-cost solution for reducing the transfer of the force F into the traction battery pack  18  and thus improves the structural performance of the traction battery pack  18  during the energy distribution event. 
     The exemplary traction battery pack rigid linkages of this disclosure provide efficient and low cost strategies for energy distribution of underbody mounted battery structures. By moving/articulating the traction battery pack away from vehicle impact zones, the transfer of loads into the traction battery pack is minimized or even eliminated. The proposed designs are highly feasible by virtue of simple linkage attachments and detachments and can be scalable for use on multiple vehicle platforms. The mounting systems of this disclosure provide improved solutions for packaging, serviceability, structural integrity, and protection of electrified vehicle traction battery packs. 
     Although the different non-limiting embodiments are illustrated as having specific components or steps, the embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from any of the non-limiting embodiments in combination with features or components from any of the other non-limiting embodiments. 
     It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should be understood that although a particular component arrangement is disclosed and illustrated in these exemplary embodiments, other arrangements could also benefit from the teachings of this disclosure. 
     The foregoing description shall be interpreted as illustrative and not in any limiting sense. A worker of ordinary skill in the art would understand that certain modifications could come within the scope of this disclosure. For these reasons, the following claims should be studied to determine the true scope and content of this disclosure.