Abstract:
A battery assembly according to an exemplary aspect of the present disclosure includes, among other things, a terminal holder, a terminal at least partially surrounded by the terminal holder, and a bus bar module connectable to the terminal holder. One of the terminal holder and the bus bar module includes at least one locating feature to position the bus bar module in a welding position relative to the terminal.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates to an electrified vehicle, and more particularly, but not exclusively, to electrically connecting bus bars to terminals of a battery assembly of the electrified vehicle. 
       BACKGROUND 
       [0002]    Hybrid electric vehicles (HEV&#39;s), plug-in hybrid electric vehicles (PHEV&#39;s), battery electric vehicles (BEV&#39;s), fuel cell vehicles and other known electrified vehicles differ from conventional motor vehicles in that are powered by one or more electric machines (i.e., electric motors and/or generators) instead of or in addition to an internal combustion engine. High voltage current is typically supplied by one or more battery assemblies that store electrical power for powering the electric machine(s). 
         [0003]    Electrified vehicle battery assemblies include one or more battery cells that are configured in a series or series-parallel string in order to obtain the voltage and power levels that are necessary to drive the electrified vehicle. The battery cells must be reliably connected to one another in order to achieve these voltage and power levels. Bus bars may be used to electrically connect the battery cells of a battery assembly. The bus bars are commonly located and secured to the terminals of the battery cells via a bolted joint. 
       SUMMARY 
       [0004]    A battery assembly according to an exemplary aspect of the present disclosure includes, among other things, a terminal holder, a terminal at least partially surrounded by the terminal holder, and a bus bar module connectable to the terminal holder. One of the terminal holder and the bus bar module includes at least one locating feature to position the bus bar module in a welding position relative to the terminal. 
         [0005]    In a further non-limiting embodiment of the foregoing battery assembly, the at least one locating feature includes a pin structure. 
         [0006]    In a further non-limiting embodiment of either of the foregoing battery assemblies, the pin structure is received within an opening of the other of the terminal holder and the bus bar module. 
         [0007]    In a further non-limiting embodiment of any of the foregoing battery assemblies, the at least one locating feature extends from the terminal holder. 
         [0008]    In a further non-limiting embodiment of any of the foregoing battery assemblies, the at least one locating feature extends from the bus bar module. 
         [0009]    In a further non-limiting embodiment of any of the foregoing battery assemblies, the at least one locating feature includes a plurality of clips configured to snap into openings of the other of the terminal holder and the bus bar module. 
         [0010]    In a further non-limiting embodiment of any of the foregoing battery assemblies, the bus bar module includes a housing and a bus bar. 
         [0011]    In a further non-limiting embodiment of any of the foregoing battery assemblies, at least one tab is configured to retain the bus bar relative to the housing. 
         [0012]    In a further non-limiting embodiment of any of the foregoing battery assemblies, the terminal includes a landing that contacts the bus bar module and a base in contact with the terminal holder. 
         [0013]    In a further non-limiting embodiment of any of the foregoing battery assemblies, the landing extends along a first plane and the base extends along a second plane that is spaced from the first plane. 
         [0014]    A battery assembly according to an exemplary aspect of the present disclosure includes, among other things, a terminal holder and a bus bar module configured to attach to the terminal holder. One of the terminal holder and the bus bar module includes a locating feature and the other of the terminal holder and the bus bar module includes an opening configured to receive the locating feature. 
         [0015]    In a further non-limiting embodiment of the foregoing battery assembly, a terminal extends at least partially between the terminal holder and the bus bar module. 
         [0016]    In a further non-limiting embodiment of either of the foregoing battery assemblies, the terminal includes a landing that extends along a first plane and a base that extends along a second plane that is spaced from the first plane. 
         [0017]    In a further non-limiting embodiment of any of the foregoing battery assemblies, the locating feature includes a pin structure that extends from the terminal holder. 
         [0018]    In a further non-limiting embodiment of any of the foregoing battery assemblies, the locating feature includes a clip that extends from the bus bar module. 
         [0019]    A method according to another exemplary aspect of the present disclosure includes, among other things, locating a bus bar module relative to a terminal of a battery assembly, connecting the bus bar module to a terminal holder and welding the bus bar module to the terminal after the connecting step. 
         [0020]    In a further non-limiting embodiment of the foregoing method, the step of locating includes inserting a pin structure of one of the terminal holder and the bus bar module into an opening in the other of the terminal holder and the bus bar module. 
         [0021]    In a further non-limiting embodiment of either of the foregoing methods, the step of locating includes inserting a clip of one of the terminal holder and the bus bar module into an opening in the other of the terminal holder and the bus bar module. 
         [0022]    In a further non-limiting embodiment of any of the foregoing methods, the step of connecting includes snapping the bus bar module onto the terminal holder. 
         [0023]    In a further non-limiting embodiment of any of the foregoing methods, the step of welding includes positioning a weld tool relative to a window of the bus bar module and using the weld tool to weld a bus bar of the bus bar module to the terminal. 
         [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 that can be incorporated into an electrified vehicle. 
           [0028]      FIG. 3  illustrates an exemplary terminal of a battery cell. 
           [0029]      FIG. 4  illustrates an exemplary bus bar module. 
           [0030]      FIG. 5  illustrates a method for electrically connecting battery cells of a battery assembly with a bus bar module. 
           [0031]      FIG. 6  illustrates a locating feature for locating a bus bar module relative to a battery terminal. 
           [0032]      FIG. 7  illustrates another exemplary battery assembly. 
       
    
    
     DETAILED DESCRIPTION 
       [0033]    This disclosure relates to a locating feature and method for locating a bus bar module relative to a terminal of a battery cell of an electrified vehicle battery assembly. The locating feature may be incorporated into either a bus bar module or a terminal holder and is configured to both laterally and vertically locate the bus bar module at a proper position relative to the terminal. Once located, a bus bar of the bus bar module can be welded to the terminal to electrically connect the battery cells of the battery assembly. These and other features are discussed in greater detail herein. 
         [0034]      FIG. 1  schematically illustrates a powertrain  10  for an electrified vehicle  12 , such as a HEV. Although depicted as a 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, PHEV&#39;s, BEV&#39;s, and fuel cell vehicles. 
         [0035]    In one embodiment, the powertrain  10  is a powersplit system that employs a first drive system that includes a combination of an engine  14  and a generator  16  (i.e., a first electric machine) and a second drive system that includes at least a motor  36  (i.e., a second electric machine), the generator  16  and a battery assembly  50 . For example, the motor  36 , the generator  16  and the battery assembly  50  may make up an electric drive system  25  of the powertrain  10 . The first and second drive systems generate torque to drive one or more sets of vehicle drive wheels  30  of the electrified vehicle  12 , as discussed in greater detail below. 
         [0036]    The engine  14 , such as an internal combustion engine, and the generator  16  may be connected through a power transfer unit  18 . In one non-limiting embodiment, the power transfer unit  18  is 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  16 . The power transfer unit  18  may include a ring gear  20 , a sun gear  22  and a carrier assembly  24 . The generator  16  is driven by the power transfer unit  18  when acting as a generator to convert kinetic energy to electrical energy. The generator  16  can alternatively function as a motor to convert electrical energy into kinetic energy, thereby outputting torque to a shaft  26  connected to the carrier assembly  24  of the power transfer unit  18 . Because the generator  16  is operatively connected to the engine  14 , the speed of the engine  14  can be controlled by the generator  16 . 
         [0037]    The ring gear  20  of the power transfer unit  18  may be connected to a shaft  28  that is connected to vehicle drive wheels  30  through a second power transfer unit  32 . The second power transfer unit  32  may include a gear set having a plurality of gears  34 A,  34 B,  34 C,  34 D,  34 E, and  34 F. Other power transfer units may also be suitable. The gears  34 A- 34 F transfer torque from the engine  14  to a differential  38  to provide traction to the vehicle drive wheels  30 . The differential  38  may include a plurality of gears that enable the transfer of torque to the vehicle drive wheels  30 . The second power transfer unit  32  is mechanically coupled to an axle  40  through the differential  38  to distribute torque to the vehicle drive wheels  30 . 
         [0038]    The motor  36  can also be employed to drive the vehicle drive wheels  30  by outputting torque to a shaft  46  that is also connected to the second power transfer unit  32 . In one embodiment, the motor  36  and the generator  16  are part of a regenerative braking system in which both the motor  36  and the generator  16  can be employed as motors to output torque. For example, the motor  36  and the generator  16  can each output electrical power to a high voltage bus  48  and the battery assembly  50 . The battery assembly  50  may be a high voltage battery that is capable of outputting electrical power to operate the motor  36  and the generator  16 . Other types of energy storage devices and/or output devices can also be incorporated for use with the electrified vehicle  12 . 
         [0039]    The motor  36 , the generator  16 , the power transfer unit  18 , and the power transfer unit  32  may generally be referred to as a transaxle  42 , or transmission, of the electrified vehicle  12 . Thus, when a driver selects a particular shift position, the transaxle  42  is appropriately controlled to provide the corresponding gear for advancing the electrified vehicle  12  by providing traction to the vehicle drive wheels  30 . 
         [0040]    The powertrain  10  may additionally include a control system  44  for monitoring and/or controlling various aspects of the electrified vehicle  12 . For example, the control system  44  may communicate with the electric drive system  25 , the power transfer units  18 ,  32  or other components to monitor and/or control the electrified vehicle  12 . The control system  44  includes electronics and/or software to perform the necessary control functions for operating the electrified vehicle  12 . In one embodiment, the control system  44  is a combination vehicle system controller and powertrain control module (VSC/PCM). Although it is shown as a single hardware device, the control system  44  may include multiple controllers in the form of multiple hardware devices, or multiple software controllers within one or more hardware devices. 
         [0041]    A controller area network (CAN)  52  allows the control system  44  to communicate with the transaxle  42 . For example, the control system  44  may receive signals from the transaxle  42  to indicate whether a transition between shift positions is occurring. The control system  44  may also communicate with a battery control module of the battery assembly  50 , or other control devices. 
         [0042]    Additionally, the electric drive system  25  may include one or more controllers  54 , such as an inverter system controller (ISC). The controller  54  is configured to control specific components within the transaxle  42 , such as the generator  16  and/or the motor  36 , such as for supporting bidirectional power flow. In one embodiment, the controller  54  is an inverter system controller combined with a variable voltage converter (ISC/VVC). 
         [0043]    The battery assembly  50  is an exemplary energy storage device for use with the electrified vehicle  12 . The battery assembly  50  may be a high voltage battery that is capable of outputting electrical power to operate the motor  36  and/or the generator  16 . Other types of energy storage devices and/or outputting devices can also be used with the electrified vehicle  12 . The battery assembly  50  may include one or more battery cells  60  (shown schematically in  FIG. 1 ), such as lithium-ion battery cells. The battery cells  60  must be electrically coupled to one another in order to drive the motor  36  and/or generator  16 . Exemplary bus bar modules for electrically connecting the battery cells  60  are described in greater detail below. 
         [0044]      FIG. 2  illustrates an exemplary battery assembly  50  that may include two or more battery cells  60  that store power for driving the electric machines  16 ,  36  of the electrified vehicle  12  (see  FIG. 1 ). In this embodiment, the battery assembly  50  is shown with two battery cells. However, the battery assembly  50  could include any number of battery cells  60  within the scope of this disclosure. The number of battery cells  60  could depend on the energy requirements of the loads being powered by the battery assembly  50 , among other design criteria. 
         [0045]    Each battery cell  60  may include two terminals  64  that extend from a surface  69  of the battery cell  60 . A terminal holder  65  generally surrounds each terminal  64 . In one non-limiting embodiment, one terminal holder  65  extends about a perimeter of each terminal  64 . The terminal holders  65  are attached to the surface  69  and may support, protect, and/or isolate the terminals  64 . 
         [0046]    A bus bar module  62  may be employed to electrically connect the battery cells  60  of the battery assembly  50 . In one embodiment, the bus bar module  62  connects to one or more terminal holders  65  to locate and secure the bus bar module  62  relative to the terminals  64  of the battery cells  60 . 
         [0047]    In one non-limiting embodiment, the terminals  64  are made of a metallic conductive material and the bus bar module  62  and terminal holders  65  include a polymeric material. Other materials may also be used within the scope of this disclosure. 
         [0048]      FIG. 3  illustrates an exemplary terminal  64  that can be incorporated into a battery cell  60  of the battery assembly  50 . In this embodiment, the terminal  64  includes a “diving board” shape. For example, the exemplary terminal  64  may include a landing  66  and a base  68 . A connector  70  joins the landing  66  to the base  68 . In one embodiment, the connector  70  is slightly curved to join the landing  66  to the base  68 . The landing  66  of the terminal  64  may be secured to the bus bar module  62  and may hover above the terminal holder  65 , whereas the base  68  of the terminal  64  may be secured directly to the terminal holder  65  (see left hand side of  FIG. 2 ). 
         [0049]    In one non-limiting embodiment, the landing  66  extends along a first plane P 1  and the base  68  extends along a second plane P 2 . The first plane P 1  may be spaced by a distance D from the second plane P 2 . In other words, the landing  66  may be slightly elevated relative to the base  68 . 
         [0050]      FIG. 4  illustrates an exemplary bus bar module  62  that may be employed to electrically connect adjacent battery cells  60  of a battery assembly  50  (see  FIG. 2 ). The bus bar module  62  may include a bus bar  72  and a housing  74 . The bus bar  72  may be made of a metallic, conductive material similar (or dissimilar) to that of the terminals  64  (see  FIG. 3 ), whereas the housing  74  may be constructed of a polymeric material. 
         [0051]    In one embodiment, the bus bar  72  is held against an inner surface  76  of the housing  74  by one or more tabs  78 . The tabs  78  may protrude from sidewalls  79  of the housing  74  and extend in a direction toward an opposite sidewall  79 . Any number and configuration of tabs may be provided to retain the bus bar  72  relative to the housing  74 . 
         [0052]    The bus bar module  62  may additionally include one or more locating features  80  for locating the bus bar module  62  in a welding position relative to a terminal. For example, it may be desirable to locate the bus bar module  62  in a position appropriate for welding the bus bar  72  to terminals  64  to electrically connect battery cells  60  of a battery assembly  50  (see  FIG. 2 ). 
         [0053]    In one non-limiting embodiment, the bus bar module  62  includes a plurality of locating features  80  that extend inwardly from a bottom surface  81  of the sidewalls  79  of the housing  74 . Any number of locating features  80  could be designed as part of the housing  74 . The locating features  80  may be tabs, clips or other features that are configured to snap or connect to corresponding openings  82  formed in the terminal holders  65  (see  FIG. 2 ). Of course, an opposite configuration is contemplated in which the locating features are formed as part of the terminal holders  65  and the openings are formed in the bus bar module  62  (see, for example,  FIG. 7 ). 
         [0054]    In one non-limiting embodiment, the locating features  80  include ledges  85 . The ledges  85  may be received through openings  82  of the terminal holder  65  and may then abut a surface of the terminal holder  65  (see  FIGS. 2 and 5 ) to provide a snap fit connection between the bus bar module  62  and the terminal holder  65 . 
         [0055]    At least one sidewall (here, the sidewall  79 -A) of the housing  74  may exclude any locating features  80 . Once connected and in the welding position, the sidewall  79 -A of the bus bar module  62  is located above the terminal(s)  64  and therefore does not require any feature for mating with the terminal holder  65  (see  FIG. 2 ). 
         [0056]    The housing  74  of the bus bar module  62  may additionally include one or more windows  84 . As discussed in greater detail below, the windows  84  can accommodate a weld tool for welding the bus bar  72  to the terminal(s)  64  once the bus bar module  62  is properly located and positioned in a welding position. 
         [0057]      FIG. 5 , with continued reference to  FIGS. 1-4 , schematically illustrates a method for electrically connecting battery cells  60  of a battery assembly  50  with a bus bar module  62 . A bus bar module  62  is first located in a welding position relative to a terminal  64  of a battery cell  60  via the locating features  80 . For example, the locating features  80  of the housing  74  of the bus bar module  62  may be aligned and positioned directly over the openings  82  of the terminal holder  65 . 
         [0058]    Next, once the locating features  80  are positioned relative to the openings  82 , the bus bar module  62  may be secured relative to the terminal holder  65 . In one non-limiting embodiment, the locating features  80  are configured as clips and the bus bar module  62  is snap fit onto the terminal holder  65 . Once connected, the ledges  85  of the locating features  80  may abut against a surface  87  that surrounds the openings  82  of the terminal holder  65  to retain the bus bar module  62  to the terminal holder  65  (see  FIG. 6 ). The bus bar module  62  is secured in a welding position once connected to the terminal holder  65  and is properly located in each of an X direction (a first lateral direction), a Y direction (a second lateral direction) and a Z direction (a vertical direction) by the locating features  80 . In other words, the locating features  80  both laterally and vertically locate the bus bar module  62  at a proper position relative to the terminal(s)  64 . 
         [0059]    Once positioned in the welding position, the bus bar  72  of the bus bar module  62  may be welded to one or more terminals  64 . In one embodiment, a weld tool  86  is positioned relative to the windows  84  of the housing  74  of the bus bar module  62  and may be used to weld the bus bar  72  directly to the landing  66  of the terminal  64  at welds W. The landing  66  may be flat or planar in order to facilitate receiving the welds W. The exemplary welds W may be laser welded lap joints, ultrasonic welds, resistance welds, etc. The welding process fuses the bus bar  72  to a portion of the terminal  64  in order to electrically connect adjacent battery cells  60 . Several separate welds W may be used to secure the bus bar  72  to the terminal  64 . 
         [0060]    Another exemplary battery assembly  150  is illustrated in  FIG. 7 . 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. 
         [0061]    In this alternative embodiment, a locating feature  180  extends from a terminal holder  165  rather than a bus bar module  162  of the battery assembly  150 . The locating feature  180  may be received by an opening  182  formed in the bus bar module  162  to secure the bus bar module  162  to the terminal holder  165 . In one non-limiting embodiment, the locating feature  180  includes a pin structure  190 . The pin structure  190  can have a round cross-section, a rectangular cross-section, a tapering cross-section, etc. The pin structure  190  limits lateral movement of the bus bar module  162  relative to a terminal  164  of the battery cell  160 . Once the pin structure  190  is received by the opening  182 , a landing  166  of the terminal  164  can be welded to the bus bar  72  of the bus bar module  162  in a manner similar to that shown in  FIG. 5 . 
         [0062]    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. 
         [0063]    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. 
         [0064]    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.