Abstract:
A battery pack according to an exemplary aspect of the present disclosure includes, among other things, an array plate including a first engagement feature configured to engage a second engagement feature when the first engagement feature is positioned proximate another structure equipped with the second engagement feature.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates to a battery pack for an electrified vehicle. A battery assembly of the battery pack includes an array plate having a first engagement feature configured to engage a second engagement feature of a structure positioned proximate to the battery assembly. 
       BACKGROUND 
       [0002]    The need to reduce automotive fuel consumption and emissions is well known. Therefore, vehicles are being developed that reduce or completely eliminate reliance on internal combustion engines. Electrified vehicles are one type of vehicle currently being developed for this purpose. In general, electrified vehicles differ from conventional motor vehicles because they are selectively driven by one or more battery powered electric machines. Conventional motor vehicles, by contrast, rely exclusively on the internal combustion engine to drive the vehicle. 
         [0003]    A high voltage battery pack for powering electric machines and other electrical loads typically includes multiple battery assemblies, or battery arrays, that include a plurality of interconnected battery cells. There is often a limited amount of space available within the electrified vehicle for accommodating the battery pack. Therefore, space efficient packagings are desired. 
       SUMMARY 
       [0004]    A battery pack according to an exemplary aspect of the present disclosure includes, among other things, an array plate including a first engagement feature configured to engage a second engagement feature when the first engagement feature is positioned proximate another structure equipped with the second engagement feature. 
         [0005]    In a further non-limiting embodiment of the foregoing battery pack, the array plate includes a first side region facing toward a battery cell and a second side region facing in a direction away from the battery cell. 
         [0006]    In a further non-limiting embodiment of either of the foregoing battery packs, the first engagement feature protrudes from the second side region. 
         [0007]    In a further non-limiting embodiment of any of the foregoing battery packs, the structure is a second array plate. 
         [0008]    In a further non-limiting embodiment of any of the foregoing battery packs, the structure is an enclosure. 
         [0009]    In a further non-limiting embodiment of any of the foregoing battery packs, the first engagement feature is a protrusion and the second engagement feature is a channel. 
         [0010]    In a further non-limiting embodiment of any of the foregoing battery packs, the first engagement feature and the second engagement feature are trapezoidal shaped. 
         [0011]    In a further non-limiting embodiment of any of the foregoing battery packs, the array plate is disposed at a first longitudinal extent of a first grouping of battery cells, and the second engagement feature is part of a second array plate disposed at a second longitudinal extent of a second grouping of battery cells. 
         [0012]    In a further non-limiting embodiment of any of the foregoing battery packs, both of the array plate and the second array plate include a plurality of the first engagement feature and a plurality of the second engagement feature. 
         [0013]    In a further non-limiting embodiment of any of the foregoing battery packs, the array plate is disposed along a side of a first grouping of battery cells, and the second engagement feature is part of a second array plate and is disposed along a second side of a second grouping of battery cells. 
         [0014]    A battery pack according to another exemplary aspect of the present disclosure includes, among other things, a first battery assembly including a first array plate, a second battery assembly adjacent to the first battery assembly and an enclosure at least partially surrounding the first battery assembly and the second battery assembly. At least one of the second battery assembly and the enclosure is configured to interlock with the first array plate. 
         [0015]    In a further non-limiting embodiment of the foregoing battery pack, the first array plate interlocks with the enclosure, and a second array plate of the first battery assembly interlocks with a third array plate of the second battery assembly. 
         [0016]    In a further non-limiting embodiment of either of the forgoing battery packs, each of the first battery assembly, the second battery assembly and the enclosure include a plurality of first engagement features and a plurality of second engagement features. 
         [0017]    In a further non-limiting embodiment of any of the foregoing battery packs, the enclosure includes a rib that extends between at least two walls of the enclosure. 
         [0018]    In a further non-limiting embodiment of any of the foregoing battery packs, the rib is configured to interlock with the first array plate. 
         [0019]    In a further non-limiting embodiment of any of the foregoing battery packs, the enclosure includes a clamping feature configured to retain at least the first battery assembly within the enclosure. 
         [0020]    In a further non-limiting embodiment of any of the foregoing battery packs, a spacer is positioned between the first battery assembly and the second battery assembly. 
         [0021]    In a further non-limiting embodiment of any of the foregoing battery packs, a cold plate is in contact with at least one of the first battery assembly and the second battery assembly. 
         [0022]    A method according to another exemplary aspect of the present disclosure includes, among other things, inserting a first battery assembly into an enclosure of a battery pack such that a first engagement feature of an array plate of the first battery assembly interlocks with a second engagement feature of either the enclosure or a second battery assembly. 
         [0023]    In a further non-limiting embodiment of the foregoing method, the inserting step includes sliding the first battery assembly into the enclosure from a top of the enclosure toward a bottom of the enclosure. 
         [0024]    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. 
         [0025]    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 
         [0026]      FIG. 1  schematically illustrates a powertrain of an electrified vehicle. 
           [0027]      FIG. 2  illustrates a battery assembly of an electrified vehicle. 
           [0028]      FIG. 3  illustrates an array plate of a battery assembly. 
           [0029]      FIG. 4  illustrates a pair of interlocked battery assemblies. 
           [0030]      FIG. 5  illustrates another pair of interlocked battery assemblies. 
           [0031]      FIG. 6  illustrates a battery pack. 
           [0032]      FIG. 7  illustrates another battery pack. 
           [0033]      FIG. 8  illustrates another battery pack. 
           [0034]      FIG. 9  illustrates yet another battery pack. 
           [0035]      FIG. 10  illustrates yet another battery pack. 
       
    
    
     DETAILED DESCRIPTION 
       [0036]    This disclosure details several exemplary battery packs for use within an electrified vehicle. One exemplary battery pack includes an array plate having a first engagement feature configured to engage a second engagement feature when the first engagement feature is positioned proximate to the second engagement feature. In some embodiments, the second engagement feature is part of a second battery assembly located adjacent to the first battery assembly. In other embodiments, the second engagement feature is part of an enclosure of the battery pack. These and other features are discussed in greater detail in the following paragraphs of this detailed description. 
         [0037]      FIG. 1  schematically illustrates a powertrain  10  of an electrified vehicle  12 . Although depicted as a hybrid electric vehicle (HEV), it should be understood that the concepts described herein are not limited to HEV&#39;s and could extend to other electrified vehicles, including, but not limited to, plug-in hybrid electric vehicles (PHEV&#39;s), battery electric vehicles (BEV&#39;s) and fuel cell vehicles. 
         [0038]    In one non-limiting embodiment, the powertrain  10  is a power-split powertrain system that employs a first drive system and a second drive system. The first drive system includes a combination of an engine  14  and a generator  18  (i.e., a first electric machine). The second drive system includes at least a motor  22  (i.e., a second electric machine), the generator  18 , and a battery pack  24 . In this example, the second drive system is considered an electric drive system of the powertrain  10 . The first and second drive systems generate torque to drive one or more sets of vehicle drive wheels  28  of the electrified vehicle  12 . Although a power-split configuration is shown, this disclosure extends to any hybrid or electric vehicle including full hybrids, parallel hybrids, series hybrids, mild hybrids or micro hybrids. 
         [0039]    The engine  14 , which in one embodiment is an internal combustion engine, and the generator  18  may be connected through a power transfer unit  30 , such as a planetary gear set. Of course, other types of power transfer units, including other gear sets and transmissions, may be used to connect the engine  14  to the generator  18 . In one non-limiting embodiment, the power transfer unit  30  is a planetary gear set that includes a ring gear  32 , a sun gear  34 , and a carrier assembly  36 . 
         [0040]    The generator  18  can be driven by the engine  14  through the power transfer unit  30  to convert kinetic energy to electrical energy. The generator  18  can alternatively function as a motor to convert electrical energy into kinetic energy, thereby outputting torque to a shaft  38  connected to the power transfer unit  30 . Because the generator  18  is operatively connected to the engine  14 , the speed of the engine  14  can be controlled by the generator  18 . 
         [0041]    The ring gear  32  of the power transfer unit  30  may be connected to a shaft  40 , which is connected to vehicle drive wheels  28  through a second power transfer unit  44 . The second power transfer unit  44  may include a gear set having a plurality of gears  46 . Other power transfer units may also be suitable. The gears  46  transfer torque from the engine  14  to a differential  48  to ultimately provide traction to the vehicle drive wheels  28 . The differential  48  may include a plurality of gears that enable the transfer of torque to the vehicle drive wheels  28 . In one embodiment, the second power transfer unit  44  is mechanically coupled to an axle  50  through the differential  48  to distribute torque to the vehicle drive wheels  28 . 
         [0042]    The motor  22  can also be employed to drive the vehicle drive wheels  28  by outputting torque to a shaft  52  that is also connected to the second power transfer unit  44 . In one embodiment, the motor  22  and the generator  18  cooperate as part of a regenerative braking system in which both the motor  22  and the generator  18  can be employed as motors to output torque. For example, the motor  22  and the generator  18  can each output electrical power to the battery pack  24 . 
         [0043]    The battery pack  24  is an exemplary electrified vehicle battery. The battery pack  24  may be a high voltage traction battery pack that includes a plurality of battery assemblies  25  (i.e., battery arrays or groupings of battery cells) capable of outputting electrical power to operate the motor  22 , the generator  18  and/or other electrical loads of the electrified vehicle  12 . Other types of energy storage devices and/or output devices can also be used to electrically power the electrified vehicle  12 . 
         [0044]    In one non-limiting embodiment, the electrified vehicle  12  has two basic operating modes. The electrified vehicle  12  may operate in an Electric Vehicle (EV) mode where the motor  22  is used (generally without assistance from the engine  14 ) for vehicle propulsion, thereby depleting the battery pack  24  state of charge up to its maximum allowable discharging rate under certain driving patterns/cycles. The EV mode is an example of a charge depleting mode of operation for the electrified vehicle  12 . During EV mode, the state of charge of the battery pack  24  may increase in some circumstances, for example due to a period of regenerative braking. The engine  14  is generally OFF under a default EV mode but could be operated as necessary based on a vehicle system state or as permitted by the operator. 
         [0045]    The electrified vehicle  12  may additionally operate in a Hybrid (HEV) mode in which the engine  14  and the motor  22  are both used for vehicle propulsion. The HEV mode is an example of a charge sustaining mode of operation for the electrified vehicle  12 . During the HEV mode, the electrified vehicle  12  may reduce the motor  22  propulsion usage in order to maintain the state of charge of the battery pack  24  at a constant or approximately constant level by increasing the engine  14  propulsion. The electrified vehicle  12  may be operated in other operating modes in addition to the EV and HEV modes within the scope of this disclosure. 
         [0046]      FIG. 2  illustrates a battery assembly  25  that can be employed within an electrified vehicle. For example, the battery assembly  25  could be part of the battery pack  24  of the electrified vehicle  12  shown in  FIG. 1 . The battery assembly  25  includes a plurality of battery cells  56  for supplying electrical power to various electrical loads of the electrified vehicle  12 . Although a specific number of battery cells  56  are depicted in  FIG. 2 , the battery assembly  25  could employ a greater or fewer number of battery cells within the scope of this disclosure. In other words, this disclosure is not limited to the specific configuration shown in  FIG. 2 . 
         [0047]    The battery cells  56  may be stacked side-by-side along a longitudinal axis A to construct a grouping of battery cells  56 , sometimes referred to as a “cell stack.” In one non-limiting embodiment, the battery cells  56  are prismatic, lithium-ion cells. However, battery cells having other geometries (cylindrical, pouch, etc.), other chemistries (nickel-metal hydride, lead-acid, etc.), or both, could alternatively be utilized within the scope of this disclosure. Although not shown, spacers or separators may be positioned between adjacent battery cells  56 . The spacers electrically isolate the battery cells  56  from one another. 
         [0048]    In one non-limiting embodiment, the battery cells  56  are supported by a support structure  58 . The support structure  58  may include two or more array plates  60  that are configured to axially constrain the stacked battery cells  56 . In one non-limiting embodiment, the array plates  60  are disposed at the longitudinal extents of the battery assembly  25  (see, e.g.,  FIG. 4 ). In other words, the array plates  60  could be configured as end walls of the support structure  58 . In another non-limiting embodiment, the array plates  60  are disposed along the sides of the battery assembly  25  (see, e.g.,  FIG. 5 ). In other words, the array plates  60  could be configured as side walls of the support structure  58 . In yet another non-limiting embodiment, the support structure  58  could include array plates  60  disposed along both the sides and ends of the battery assembly  25  (see, e.g.,  FIG. 2 ). As discussed in greater detail below, one or more of the array plates  60  may include engagement features for interlocking with corresponding engagement features of other structures positioned proximate to the battery assembly  25 , such as, for example, another battery assembly or a battery pack enclosure. 
         [0049]    An exemplary array plate  60  is illustrated in  FIG. 3 . The array plate  60  includes a first side region  62  and a second side region  64  opposite of the first side region  62 . In one embodiment, the first side region  62  faces toward the battery cells  56 , and the second side region  64  faces in a direction away from the battery cells  56  (see, e.g.,  FIG. 2 ). 
         [0050]    The array plate  60  may be made of either metallic materials (aluminum, steel, etc.) or plastic materials. In one non-limiting embodiment, the array plate  60  is an extruded part. However, other manufacturing techniques, including but not limited to casting techniques, can be used to form the array plate  60 . 
         [0051]    The second side region  64  of the array plate  60  includes first engagement features  66  and second engagement features  68 . The array plate  60  could include any amount of the first and second engagement features  66 ,  68  and is not limited to the specific arrangement of features shown in  FIG. 3 . The first engagement features  66  may protrude outwardly from the second side region  64  in a direction that extends away from the first side region  62 , and the second engagement features  68  may extend between adjacent first engagement features  66 . 
         [0052]    In one non-limiting embodiment, the first engagement features  66  are protrusions and the second engagement features  68  are channels. In another non-limiting embodiment, the first engagement features  66  and the second engagement features  68  are trapezoidal shaped. However, other shapes and configurations are also contemplated within the scope of this disclosure. 
         [0053]    Referring now to  FIG. 4 , the first engagement features  66  of the array plate  60  are configured to interlock with corresponding second engagement features  68 - 2  of a second array plate  60 - 2  when the second array plate  60 - 2  is positioned proximate to the array plate  60 . The second array plate  60 - 2  is common (i.e., has the same overall design and features) to the array plate  60 . However, because the array plate  60  and the second array plate  60 - 2  are disposed at opposite ends of their respective battery assemblies  25 ,  25 - 2  (i.e., one on the right hand side and the other on the left hand side), the first engagement features  66  of the array plate  60  are aligned with the second engagement features  68 - 2  of the second array plate  60 - 2  when the second battery assembly  25 - 2  is positioned proximate to the battery assembly  25 . Similarly, the first engagement features  66 - 2  of the second array plate  60 - 2  may interlock or engage the second engagement features  68  of the array plate  60 . In this way, the battery assembly  25  and the second battery assembly  25 - 2  may be secured together end-to-end. A similar interconnection can be achieved along the sides of the battery assembly  25  and the second battery assembly  25 - 2  by providing first and second array plates  60 ,  60 - 2  each having first engagement features  66 ,  66 - 2  and second engagement features  68 ,  68 - 2  that are configured to interlock with one another (see  FIG. 5 ). 
         [0054]      FIG. 6  is a top view of an exemplary battery pack  24 . The battery pack  24  includes a plurality of battery assemblies  25  that are generally surrounded by an enclosure  70 . The enclosure  70  includes a plurality of wall  72 . In this embodiment, a top wall or cover of the enclosure  70  is removed to better illustrate the internal contents of the battery pack  24 . 
         [0055]    Each battery assembly  25  of the battery pack  24  may include a plurality of battery cells  56  disposed between opposing array plates  60  positioned at the longitudinal extents of the battery assemblies  25 . Each array plate  60  includes first engagement features  66  and second engagement features  68  for securing the battery assembly  25  within the enclosure  70 . 
         [0056]    In one non-limiting embodiment, a portion of the walls  72  of the enclosure  70  include first engagement features  74  and second engagement features  76 . The first and second engagement features  74 ,  76  may be integral with the walls  72  or could be separate inserts that are attached to the walls  72 . The first engagement features  66  of the array plates  60  are configured to interlock with the second engagement features  76  of the walls  72  of the enclosure  70 . Similarly, the first engagement features  74  of the walls  72  are configured to interlock with the second engagement features  68  of the array plates  60 . In this way, each battery assembly  25  can be secured to the enclosure  70 . In another non-limiting embodiment, each battery assembly  25  may be inserted into the enclosure  70  from the top of the enclosure  70  by aligning the first engagement features  66  of the array plates  60  with the second engagement features  76  of the walls  72  and then sliding each battery assembly  25  down into the enclosure  70 . The engagement features  66 ,  68 ,  74 ,  76  guide the battery assemblies  25  into place within the battery pack  24 . 
         [0057]    One or more clamping features  78  may be secured laterally across each array plate  60  of each battery assembly  25 . In one non-limiting embodiment, the clamping feature  78  is a bar or sheet secured at the edges of the battery assemblies  25 . The clamping feature  78  retains the battery assemblies  25  in the vertical direction (i.e., into the page in  FIG. 6 ). 
         [0058]      FIG. 7  is a top view of another exemplary battery pack  124 . In this disclosure, like reference numbers designate like elements where appropriate and reference numerals with the addition of 100 or multiples thereof designate modified elements that are understood to incorporate the same features and benefits of the corresponding original elements. 
         [0059]    The battery pack  124  includes a plurality of battery assemblies  125  that are generally surrounded by an enclosure  170 . The enclosure  170  includes a plurality of walls  172 . A top wall or cover of the enclosure  170  has been removed to better illustrate the internal contents of the battery pack  124 . Each battery assembly  125  of the battery pack  124  includes a plurality of battery cells  156  disposed between array plates  160 . Each array plate  160  includes first engagement features  166  and second engagement features  168 . The walls  172  of the enclosure  170  also include first engagement features  174  and second engagement features  176 . 
         [0060]    In this non-limiting embodiment, each battery assembly  125  may be secured to both the enclosure  170  and to an adjacent battery assembly  125 . For example, the first and second engagement features  166 ,  168  of some of the array plates  160  may engage or interlock with a portion of the first and second engagement features  174 ,  176  of the walls  172 , and the first and second engagement features  166 ,  168  of other of the array plates  160  may engage with corresponding first and second engagement features  166 ,  168  of proximately positioned array plates  160 . 
         [0061]      FIG. 8  is a top view of yet another exemplary battery pack  224 . The battery pack  224  includes a plurality of battery assemblies  225  that are generally surrounded by an enclosure  270  having a plurality of walls  272 . Each battery assembly  225  of the battery pack  224  includes a plurality of battery cells  256  disposed between array plates  260 . Each array plate  260  includes first engagement features  266  and second engagement features  268 . The walls  272  of the enclosure  270  also include first engagement features  274  and second engagement features  276 . 
         [0062]    In another non-limiting embodiment, the enclosure  270  includes a rib  271  that extends across the battery pack  224 , such as between two of the walls  272 . The rib  271  increases the structural integrity of the enclosure  270 . Opposing sides  273  of the rib  271  may include first and second engagement features  275 ,  277 . 
         [0063]    Each battery assembly  225  may be secured to one of the walls  272  of the enclosure  270  and to the rib  271 . For example, the first and second engagement features  266 ,  268  of some of the array plates  260  may engage with a portion of the first and second engagement features  274 ,  276  of the walls  272 , and the first and second engagement features  266 ,  268  of other of the array plates  260  may engage with first and second engagement features  275 ,  277  of the rib  271 . 
         [0064]      FIG. 9  is a side view of a battery pack  324 . The battery pack  324  includes at least one battery assembly  325  that is generally surrounded by an enclosure  370  having a plurality of walls  372  and a cover  381 . The cover  381  may be secured to some of the walls  372  using fasteners  383 . In one non-limiting embodiment, the cover  381  acts as a clamping feature for retaining the battery assembly  325  in the vertical direction. 
         [0065]    The battery assembly  325  of the battery pack  324  includes a plurality of battery cells  356  disposed between array plates  360 . The array plates  360  may include engagement features (not shown in  FIG. 9 ) for engaging corresponding engagement features of either the enclosure  370  or an adjacent battery assembly similar to any of the engagement configurations described above. 
         [0066]    In another non-limiting embodiment, a cold plate  385  may be positioned between the battery assembly  325  and one of the walls  372 , here a bottom wall, of the enclosure  370 . The cold pate  385 , which may alternatively be referred to as a heat exchanger plate, conducts heat from the battery cells  356 . The cold plate  385  may act as a heat sink for removing heat generated by the battery cells  356 . The cold plate  385  may include engagement features  387  for interlocking with the enclosure  370  in a similar manner as the battery assembly  325 . 
         [0067]      FIG. 10  is a side view of yet another battery pack  424 . The battery pack  424  may include a first battery assembly  425 - 1  and a second battery assembly  425 - 2 . In one non-limiting embodiment, the second battery assembly  425 - 2  is stacked vertically above or on top of the first battery assembly  425 - 1 . One or more spacers  495  may be positioned between the first and second battery assemblies  425 - 1 ,  425 - 2  to space them from one another and create a multi-level battery pack. 
         [0068]    The first and second battery assemblies  425 - 1 ,  425 - 2  are generally surrounded by an enclosure  470  having a plurality of walls  472  and a cover  481 . The cover  481  may be secured to some of the walls  472  using fasteners  483 . 
         [0069]    Each of the first and second battery assemblies  425  includes a plurality of battery cells  456  disposed between array plates  460 . The array plates  460  may include engagement features (not shown in  FIG. 10 ) for engaging corresponding engagement features of either the enclosure  470  or an adjacent battery assembly in any of the ways disclosed above. The spacers  495  may also include engagement features (not shown) for interlocking with the enclosure  470  in a similar manner as the battery assemblies  425 - 1 ,  425 - 2 . 
         [0070]    In another non-limiting embodiment, a cold plate  485  is positioned in contact with each of the first and second battery assemblies  425 - 1 ,  425 - 2 . The cold plates  485  act as heat sinks for removing heat generated by the battery cells  456 . 
         [0071]    The exemplary battery packs of this disclosure provide a compact and space efficient packaging design. The proposed designs substantially eliminate conventional bolting mechanisms inside the battery pack to render reduced volume packs that decrease assembly complexity and assembly time. 
         [0072]    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. 
         [0073]    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. 
         [0074]    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.