Abstract:
An assembly according to an exemplary aspect of the present disclosure includes, among other things, a plurality of battery cells and a bus bar assembly received over the plurality of battery cells. The bus bar assembly comprises a housing, a bus bar received within the housing and a retention device disengageable from the bus bar to move the bus bar between a first position and a second position.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates to a bus bar assembly for electrically connecting a grouping of battery cells of an electrified vehicle battery pack. The bus bar assembly includes a housing and a bus bar that is retained in a first position relative to a battery cell terminal and is movable to a second position relative to the battery cell terminal. 
       BACKGROUND 
       [0002]    The need to reduce automotive fuel consumption and emissions is well known. Therefore, vehicles are being developed that either reduce or completely eliminate reliance on internal combustion engines. Electrified vehicles are one type of vehicle 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 propel the vehicle. 
         [0003]    The powertrain of an electrified vehicle is typically equipped with a high voltage battery pack that includes one or more battery arrays. Each battery array includes a grouping of battery cells that store electric power for powering the electric machines and other electric loads of the vehicle. The battery cells must be reliably connected to one another in order to achieve the voltage and power levels necessary for powering these electric loads. Bus bars and other devices are commonly used to sufficiently connect the battery cells. 
       SUMMARY 
       [0004]    An assembly according to an exemplary aspect of the present disclosure includes, among other things, a plurality of battery cells and a bus bar assembly received over the plurality of battery cells. The bus bar assembly comprises a housing, a bus bar received within the housing and a retention device disengageable from the bus bar to move the bus bar between a first position and a second position. 
         [0005]    In a further non-limiting embodiment of the foregoing assembly, the bus bar is connectable to a terminal of a first battery cell and a terminal of a second battery cell in the second position. 
         [0006]    In a further non-limiting embodiment of either of the foregoing assemblies, the housing is made of a first material and the bus bar is made of a second, different material. 
         [0007]    In a further non-limiting embodiment of any of the foregoing assemblies, the retention device includes a first retention feature configured to engage a second retention feature of the bus bar to retain the bus bar in the first position. 
         [0008]    In a further non-limiting embodiment of any of the foregoing assemblies, the first retention feature is a tab or an aperture and the second retention feature is the other of the tab and the aperture. 
         [0009]    In a further non-limiting embodiment of any of the foregoing assemblies, the bus bar includes a body and a first leg and a second leg that protrude from the body. 
         [0010]    In a further non-limiting embodiment of any of the foregoing assemblies, each of the first leg and the second leg includes a slot. 
         [0011]    In a further non-limiting embodiment of any of the foregoing assemblies, a bottom of the slot abuts a battery cell terminal in the second position. 
         [0012]    In a further non-limiting embodiment of any of the foregoing assemblies, the bus bar includes a first bus bar portion and a second bus bar portion separate from the first bus bar portion. 
         [0013]    In a further non-limiting embodiment of any of the foregoing assemblies, each of the first bus bar portion and the second bus bar portion include a first opening configured to receive the retention device and a second opening configured to receive a portion of a battery cell terminal. 
         [0014]    In a further non-limiting embodiment of any of the foregoing assemblies, the retention device includes an arm that is integral with the housing. 
         [0015]    In a further non-limiting embodiment of any of the foregoing assemblies, the retention feature includes an arm that is attached to the housing. 
         [0016]    In a further non-limiting embodiment of any of the foregoing assemblies, at least one biasing member is configured to move the bus bar toward the second position upon disengaging the retention feature from the bus bar. 
         [0017]    In a further non-limiting embodiment of any of the foregoing assemblies, the at least one biasing member is a spring. 
         [0018]    In a further non-limiting embodiment of any of the foregoing assemblies, the at least one biasing member is a flexible portion of the housing. 
         [0019]    A method according to another exemplary aspect of the present disclosure includes, among other things, positioning a bus bar within a bus bar assembly to locate the bus bar in a first position relative to a battery cell terminal, holding the bus bar in the first position and moving the bus bar from the first position to a second position. 
         [0020]    In a further non-limiting embodiment of the foregoing methods, the moving step includes moving a first bus bar portion and a second bus bar portion in opposite directions from one another. 
         [0021]    In a further non-limiting embodiment of either of the foregoing methods, the method includes disengaging a retention device of the bus bar assembly from the bus bar to move the bus bar from the first position toward the second position. 
         [0022]    In a further non-limiting embodiment of any of the foregoing methods, the holding step includes retaining the bus bar in the first position with a retention device. 
         [0023]    A bus bar assembly according to another exemplary aspect of the present disclosure includes, among other things, a housing, a bus bar received within the housing and a retention device disengageable from the bus bar to move the bus bar between a first position and a second position relative to the housing. 
         [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 array according to an embodiment of this disclosure. 
           [0028]      FIG. 3  is a top view of a battery cell of the battery array of  FIG. 2 . 
           [0029]      FIGS. 4A and 4B  illustrate a bus bar assembly according to a first embodiment of this disclosure. 
           [0030]      FIG. 5  illustrates an exemplary retention configuration for retaining a bus bar of a bus bar assembly. 
           [0031]      FIG. 6  illustrates another exemplary retention configuration for retaining a bus bar of a bus bar assembly. 
           [0032]      FIGS. 7A and 7B  schematically illustrate disengagement of a retention device from a bus bar of the bus bar assembly of  FIGS. 4A and 4B . 
           [0033]      FIGS. 8A and 8B  illustrate exemplary biasing members of the bus bar assembly of  FIGS. 4A and 4B . 
           [0034]      FIGS. 9A and 9B  illustrate the bus bar assembly of  FIGS. 4A and 4B  after movement of the bus bar to a second position. 
           [0035]      FIGS. 10A and 10B  illustrate a bus bar assembly according to another embodiment of this disclosure. 
           [0036]      FIGS. 11A and 11B  illustrate the bus bar assembly of  FIGS. 10A and 10B  after movement of a bus bar to a second position. 
           [0037]      FIGS. 12A and 12B  illustrate a bus bar assembly according to yet another embodiment of this disclosure. 
           [0038]      FIGS. 13A and 13B  illustrate the bus bar assembly of  FIGS. 12A and 12B  after movement of a bus bar to a second position. 
       
    
    
     DETAILED DESCRIPTION 
       [0039]    This disclosure details a battery array for an electrified vehicle battery pack. The battery array includes a plurality of battery cells and a bus bar assembly disposed over the battery cells. The bus bar assembly may include a housing, a bus bar, and a retention device configured to hold the bus bar in a first position within the housing. The retention device may be disengaged from the bus bar to move the bus bar from the first position to a second, different position. A biasing member of the bus bar assembly is configured to move the bus bar to the second position after the retention device has disengaged from the bus bar. The bus bar is properly positioned and aligned for connection to a battery cell terminal once moved to the second position. These and other features are discussed in greater detail in the following paragraphs of this detailed description. 
         [0040]      FIG. 1  schematically illustrates a powertrain  10  for 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. 
         [0041]    In one 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. 
         [0042]    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 . 
         [0043]    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 . 
         [0044]    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 . 
         [0045]    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 . 
         [0046]    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 arrays  25  (i.e., groupings of battery cells) capable of outputting electrical power to operate the motor  22 , the generator  18  and/or other electrical loads. Other types of energy storage devices and/or output devices can also be used to electrically power the electrified vehicle  12 . 
         [0047]    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. 
         [0048]    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. 
         [0049]      FIG. 2  illustrates a battery array  25  that can be incorporated into an electrified vehicle. For example, the battery array  25  could be part of the battery pack  24  of the electrified vehicle  12  of  FIG. 1 . The battery array  25  includes a plurality of battery cells  58  for supplying electrical power to various components of the electrified vehicle  12 . Although a specific number of battery cells  58  are illustrated in  FIG. 2 , the battery array  25  could include 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 . 
         [0050]    The battery cells  58  may be stacked side-by-side along a longitudinal axis A to construct a grouping of battery cells  58 , sometimes referred to as a “cell stack.” In one embodiment, the battery cells  58  are prismatic, lithium-ion cells. However, battery cells having other geometries (cylindrical, pouch, etc.) and/or chemistries (nickel-metal hydride, lead-acid, etc.) could alternatively be utilized within the scope of this disclosure. 
         [0051]    A support structure  59 , sometimes referred to as an “array structure” or “array support structure,” generally surrounds the battery cells  58 . The support structure  59  may include opposing end walls  60  disposed at the longitudinal extents of the grouping of battery cells  58  and opposing side walls  62  that extend on both sides of the battery array  25  between the opposing end walls  60 . The end walls  60  and the side walls  62  cooperate to hold the battery cells  58  under compression relative to one another. The side walls  62  may be connected to the end walls  60  in any known manner. In another embodiment, the support structure  59  includes a bottom plate  63 , which can be configured as a heat exchanger plate to remove heat generated by the battery cells  58 . 
         [0052]    The battery array  25  may additionally include a bus bar assembly  64 . The bus bar assembly  64  rests atop the battery cells  58  and is configured to electrically connect the battery cells  58  of the battery array  25 . In one non-limiting embodiment, the bus bar assembly  64  includes a housing  66 , one or more bus bars  68 , and a retention bar  70 . The housing  66  may be made of a plastic material, and the bus bars  68  may be made of a metallic material. 
         [0053]    The bus bars  68  are received within the housing  66  such that the bus bars  68  are properly oriented relative to the battery cells  58 , and more specifically relative to terminals of the battery cells  58 . The bus bars  68  may be attached, such as by welding, to one or more terminals of the battery cells  58  so that electrical energy communicates to and from the battery cells  58  through the bus bars  68 . In another embodiment, the bus bars  68  may be attached to one or more terminals of the battery cells  58  by a mechanical joint such as a threaded stud and nut. 
         [0054]    The retention bar  70  may optionally extend over the housing  66  to retain the bus bar assembly  64  against the battery cells  58  and to provide rigidity to the battery array  25 . In another non-limiting embodiment, the retention bar  70  biases the battery cells  58  toward the bottom plate  63 . 
         [0055]    The depiction of the bus bar assembly  64  shown in  FIG. 2  is highly schematic. Accordingly, additional details of the bus bar assembly  64  are detailed below. 
         [0056]      FIG. 3  illustrates an exemplary battery cell  58  of the battery array  25  described above. The battery cell  58  includes a top surface  72  and a pair of terminals  74  that extend outwardly from the top surface  72 . The terminals  74  may be disposed near opposite ends of the top surface  72 . One of the terminals  74  is a positive terminal (designated by the symbol (+)) and the other terminal  74  is a negative terminal (designed by the symbol (−)). The battery cell  58  may be arranged such each terminal  74  is disposed adjacent to a terminal of an adjacent battery cell having an opposite polarity. For example, with reference to the embodiment of  FIG. 2 , each bus bar  68  could connect to a positive terminal on one battery cell  58  and a negative terminal on an adjacent battery cell  58 . In another embodiment, although not specifically shown, the battery cell  58  could be arranged such that each terminal  74  is disposed adjacent to a terminal of an adjacent battery cell having the same polarity. 
         [0057]    Each terminal  74  includes a contact surface  76  and a pillar  78  that protrudes upwardly from the contact surface  76 . A bus bar (not shown in  FIG. 3 ) may be attached (e.g., welded) to one or both of the contact surface  76  and the pillar  78  to electrically connect the battery cell  58  to adjacent battery cells. 
         [0058]      FIGS. 4A and 4B  illustrate portions of the bus bar assembly  64 . One of the bus bars  68  is positioned at a first position P 1  relative to the housing  66  and the terminals  74  of two adjacent battery cells  58 - 1 ,  58 - 2 . Although only a single bus bar  68  is shown, a plurality of bus bars  68  could be received within the housing  66 . In one non-limiting embodiment, the bus bar  68  includes a body  69  and a first leg  71  and a second leg  73  that extend from the body  69  (see  FIG. 4B ). Stated another way, the body  69  establishes a bridge between the first leg  71  and the second leg  73  to establish a horseshoe shaped bus bar. 
         [0059]    Each of the first leg  71  and the second leg  73  of the bus bar  68  may include a slot  75  configured to at least partially wrap around one of the terminals  74  of the battery cells  58 . The slots  75  may taper outwardly toward ends of the first leg  71  and the second leg  73 . However, the slot  75  could include other shapes and configurations. In one non-limiting embodiment, the bus bar  68  does not contact the pillars  78  of the terminals  74  when arranged in the first position P 1 . 
         [0060]    A retention device  80  may engage the bus bar  68  to hold it in the first position P 1 . The retention device  80  may be integral to the housing  66  or could be a separate component that is attached to the housing  66 . In one non-limiting embodiment, the retention device  80  is configured as an arm that includes a first retention feature  82  configured to engage a second retention feature  84  of the bus bar  68 . In this non-limiting embodiment, the first retention feature  82  is a tab and the second retention feature  84  is an aperture formed in the body  69  of the bus bar  68 . In another non-limiting embodiment, both the first retention feature  82  and the second retention feature  84  are tabs (see  FIG. 5 ) that abut one another to hold the bus bar  68  in the first position P 1 . In yet another non-limiting embodiment, the first retention feature  82  is an aperture formed in the retention device  80  and the second retention feature  84  is a tab that protrudes from the bus bar  68  and into the aperture to hold the bus bar  68  in the first position P 1  (see  FIG. 6 ). 
         [0061]    Referring now to  FIGS. 7A and 7B , the retention device  80  may be actuated to disengage the first retention feature  82  from the second retention feature  84 . In one embodiment, the first retention feature  82  is disengaged from the second retention feature  84  by applying a force in a direction D 1  to an end portion  85  of the retention device  80  that is opposite from the first retention feature  82 . Applying the force in the direction D 1  causes the retention device  80  to pivot about a wall  86  of the housing  66 , thereby moving the first retention feature  82  outwardly in a direction away from the second retention feature  84  and the bus bar  68 . Disengaging the retention device  80  from the bus bar  68  enables the bus bar  68  to begin moving in a second direction D 2  toward the terminals  74  of the battery cells  58 - 1 ,  58 - 2 . In one non-limiting embodiment, the second direction D 2  is generally perpendicular to the first direction D 1 . 
         [0062]    The bus bar assembly  64  may further include one or more biasing members  88  configured to move the bus bar  68  in the second direction D 2  after disengaging the retention device  80  from the bus bar  68 . In one non-limiting embodiment, the biasing members  88  are biased toward the terminals  74  such that the bus bars  68  are also biased toward the terminals  74 . The biasing members  88  may be part of the housing  66  (see  FIGS. 4B and 7B ), part of the bus bar  68  (see  FIG. 8A ), or could be a separate spring that is connected to both the housing  66  and the bus bar  68  (see  FIG. 8B ). 
         [0063]    In another embodiment, the bus bar assembly  64  includes additional biasing members  90  disposed along the sides of the bus bar  68  and configured to center the bus bar  68  relative to the terminals  74 . In this way, the biased bus bar  68  can absorb the various tolerances between the numerous components of a battery array during its assembly. 
         [0064]      FIGS. 9A and 9B  illustrate the bus bar  68  positioned in a second position P 2  after having moved in the direction D 2 . In the second position P 2 , the slots  75  of the first leg  71  and the second leg  73  of the bus bar  68  are received about the terminals  74  of the battery cells  58 - 1 ,  58 - 2  such that the terminals  74  abut a bottom  77  of the slot  75 . The bus bar  68  is also aligned with the pillars  78  of the terminals  74  and overlaps with the contact surface  76  of the terminals  74  in the second position P 2 . Stated another way, movement of the bus bar  68  to the second position P 2  automatically aligns and positions the bus bar  68  in a welding position relative to the terminals  74 . The bus bar  68  can then be welded to the terminals  74  to electrically connect the battery cells  58 - 1 ,  58 - 2 . Welds  92  are schematically shown to illustrate this connection. In another embodiment, although not specifically shown, the bus bars  68  may be attached to one or more terminals of the battery cells  58  by a mechanical joint such as a threaded stud and nut. 
         [0065]      FIGS. 10A and 10B  illustrate another exemplary bus bar assembly  164 . 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. 
         [0066]    In this non-limiting embodiment, the bus bar assembly  164  includes a housing  166 , a bus bar  168 , a retention device  180  and one or more biasing members  188 . In one non-limiting embodiment, the bus bar  168  is a two-piece bus bar that includes a first bus bar portion  168 - 1  and a second bus bar portion  168 - 2  that is separate from the first bus bar portion  168 - 1 . Each of the first bus bar portion  168 - 1  and the second bus bar portion  168 - 2  may include a bottom flange  191  and a top flange  193  elevated from the bottom flange  191 . The first bus bar portion  168 - 1  and the second bus bar portion  168 - 2  may be generally Z-shaped, in one non-limiting embodiment. 
         [0067]    The top flanges  193  overlap one another once positioned within the housing  166  of the bus bar assembly  164 . In addition, openings  195  are formed in both the bottom flanges  191  and the top flanges  193 . In one non-limiting embodiment, the openings  195  are oval shaped. However, other shapes are contemplated within the scope of this disclosure. 
         [0068]    The two-piece bus bar  168  of this embodiment may be retained in a first position P 1  by the retention device  180 . For example, the retention device  180  may be received within the aligned openings  195  of the top flanges  193  of both the first bus bar portion  168 - 1  and the second bus bar portion  168 - 2  to hold the bus bar  168  in the first position P 1 . In one embodiment, the retention feature  180  is a movable arm having a tab  182  that may be inserted into the openings  195  of the top flanges  193 . However, other configurations are also contemplated. The openings  195  of the bottom flanges  191  are received over pillars  178  of terminals  174  of adjacent battery cells  158 - 1 ,  158 - 2  in the first position P 1  (see  FIG. 10B ). 
         [0069]    Referring now to  FIGS. 11A and 11B  (with continued reference to  FIGS. 10A and 10B ), the retention device  180  may be disengaged from the bus bar  168  to move the bus bar  168  to a second position P 2  relative to the terminals  174 . In one non-limiting embodiment, the retention device  180  is disengaged by removing the tab  182  from the openings  195  of the top flanges  193  of the first bus bar portion  168 - 1  and the second bus bar portion  168 - 2 . Once removed, the biasing members  188 , which may include springs or other flexible components connected between the housing  166  and the first and second bus bar portions  168 - 1 ,  168 - 2 , force the first bus bar portion  168 - 1  and the second bus bar portion  168 - 2  of the bus bar  168  to move in opposite directions from one another until the pillars  178  of the terminals  174  abut longitudinal extents  199  of the openings  195  of the bottom flanges  191 . In the second position P 2 , the openings  195  of the top flanges  193  are not aligned with one another (see  FIG. 11B ). 
         [0070]    The bus bar  168  can be connected to the terminals once located in the second position P 2 . Welds  192  are schematically shown to illustrate this connection. In another embodiment, although not specifically shown, the bus bar  168  may be attached to one or more terminals  174  by a mechanical joint such as a threaded stud and nut. Additionally, the first and second bus bar portions  168 - 1 ,  168 - 2  may also be coupled together. For example, the first and second bus bar portions  168 - 1 ,  168 - 2  may be mechanical coupled together by a fastener or may be coupled together by a weld. 
         [0071]      FIGS. 12A and 12B  illustrate portions of yet another exemplary bus bar assembly  264 . A bus bar  268  of the bus bar assembly  264  is positioned at a first position P 1  relative to a housing  266  of the bus bar assembly  264  and terminals  74  of two adjacent battery cells  58 - 1 ,  58 - 2 . Although a single bus bar  268  is shown, a plurality of bus bars  268  could be received within the housing  266 . In one non-limiting embodiment, the bus bar  268  does not contact the pillars  78  of the terminals  74  when arranged in the first position P 1 . 
         [0072]    A retention device  280  may engage the bus bar  268  to hold it in the first position P 1 . In one non-limiting embodiment, the retention device  280  is configured as an arm that includes a first retention feature  282  configured to engage a second retention feature  284  of the bus bar  268 . In this non-limiting embodiment, the first retention feature  282  is a tab and the second retention feature  284  is an aperture formed in the bus bar  268 . The retention device  280  may also extend into an aperture  299  formed in the housing  266  of the bus bar assembly  264  in the first position P 1 . 
         [0073]    Referring now to  FIGS. 13A and 13B , the retention device  280  may be disengaged from the bus bar  268  to automatically move the bus bar  268  to a second position P 2  relative to the terminals  74 . In one non-limiting embodiment, the retention device  280  is disengaged by moving the bus bar assembly  264  in a direction D 1  (see  FIG. 12A ) until it contacts the top surface  72  of one or more battery cells  58 . As the bus bar assembly  264  is moved into contact with the top surfaces  72 , the retention device  280  pivots about a wall  286  of the housing  266 , thereby moving the first retention feature  282  outwardly in a direction away from the second retention feature  284 , the bus bar  268 , and the aperture  299  of the housing  266 . Once the retention device  280  is disengaged, one or more biasing members  288  automatically force the bus bar  268  to the second position P 2 . The bus bar  268  can be connected to the terminals  74  once located in the second position P 2 . Welds  292  are schematically shown to illustrate this connection. 
         [0074]    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. 
         [0075]    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. 
         [0076]    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.