Abstract:
An electric vehicle battery assembly according to an exemplary aspect of the present disclosure includes, among other things, a battery cell, a rail securing the cell, and a terminal holder in direct contact with the rail.

Description:
BACKGROUND 
     Generally, electric vehicles differ from conventional motor vehicles in that electric vehicles are selectively driven using one or more battery-powered electric machines. Conventional motor vehicles, by contrast, rely exclusively on an internal combustion engine to drive the vehicle. Electric vehicles may use electric machines instead of, or in addition to, the internal combustion engine. 
     Example electric vehicles include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). Electric vehicles are typically equipped with a battery pack containing multiple battery cells that store electrical power for powering the electric machine. The battery cells may be charged prior to use, and recharged during drive by regeneration braking or an internal combustion engine. 
     The battery cells are typically retained in place by a plurality of rails, including upper rails and side rails. In one known arrangement, a dedicated rail cover electrically insulates the cells from the rails. 
     SUMMARY 
     An electric vehicle battery assembly according to an exemplary aspect of the present disclosure includes, among other things, a battery cell, a rail securing the cell, and a terminal holder in direct contact with the rail. 
     In a further non-limiting embodiment of the foregoing battery assembly, the rail is a side rail adjacent a side of the cell, and the terminal holder includes a side rail protection portion overhanging the side of the cell. 
     In a further non-limiting embodiment of the foregoing battery assembly, the side rail protection portion includes a flange extending downward from a lower surface of a main body portion of the terminal holder, and the flange of the side rail protection portion directly contacts the side of the cell and the side rail. 
     In a further non-limiting embodiment of the foregoing battery assembly, the flange of the side rail protection portion has a thickness of at least 1.6 mm. 
     In a further non-limiting embodiment of the foregoing battery assembly, the rail is an upper rail adjacent an upper surface of the cell, and the terminal holder includes an upper rail protection portion provided by a flange extending upward from an upper surface of a main body portion of the terminal. Further, the upper rail directly contacts the flange of the upper rail protection portion. 
     In a further non-limiting embodiment of the foregoing battery assembly, the flange of the upper rail protection portion includes a first leg, a second leg, and a third leg. 
     In a further non-limiting embodiment of the foregoing battery assembly, the assembly further includes a terminal in contact with the upper surface of the main body portion of the terminal holder. Further, the flange of the upper rail protection portion extends a height of at least 1.6 mm above an upper surface of the terminal. 
     In a further non-limiting embodiment of the foregoing battery assembly, the main body portion has a height of at least 1.6 mm. 
     In a further non-limiting embodiment of the foregoing battery assembly, the terminal holder is integrally formed of a dielectric material. 
     A terminal holder for an electric vehicle battery assembly according to another exemplary aspect of this disclosure includes, among other things, a main body portion having an upper surface and a lower surface, and a side rail protection portion including a flange extending downward from the lower surface of the main body portion. 
     In a further non-limiting embodiment of the foregoing terminal holder, the flange of the side rail protection portion has a thickness of at least 1.6 mm. 
     In a further non-limiting embodiment of the foregoing terminal holder, the terminal holder further includes an upper rail protection portion including a flange extending upward from the upper surface of the main body portion. 
     In a further non-limiting embodiment of the foregoing terminal holder, the flange of the upper rail protection portion includes a first leg, a second leg, and a third leg. 
     In a further non-limiting embodiment of the foregoing terminal holder, the main body portion, the side rail protection portion, and the upper rail protection portion are integrally formed. 
     In a further non-limiting embodiment of the foregoing terminal holder, the terminal holder is made of a dielectric material. 
     In a further non-limiting embodiment of the foregoing terminal holder, the main body portion has a height of at least 1.6 mm. 
     An electric vehicle battery assembly according to an exemplary aspect of the present disclosure includes, among other things, a battery cell, a side rail adjacent a side of the cell, an upper rail adjacent an upper surface of the cell, a terminal, and a terminal holder, The terminal holder includes a main body portion in contact with the terminal. The terminal holder further includes a side rail protection portion overhanging the side of the cell and directly contacting the side rail. Additionally, the terminal holder includes an upper rail protection portion extending upward from the main body portion and directly contacting the upper rail. 
     In a further non-limiting embodiment of the foregoing battery assembly, the side rail protection portion includes a flange extending downward from a lower surface of the main body portion. 
     In a further non-limiting embodiment of the foregoing battery assembly, the upper rail protection portion includes a flange having a first leg, a second leg, and a third leg. 
     In a further non-limiting embodiment of the foregoing battery assembly, an outer surface of the second leg directly contacts the side rail, and wherein an upper surface of the second leg directly contacts the upper rail. 
     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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings can be briefly described as follows: 
         FIG. 1  is a schematic view of an example electric vehicle powertrain. 
         FIG. 2  is a schematic, perspective view of an example battery pack. 
         FIG. 3  is a perspective view of an example battery cell, including a terminal holder according to this disclosure, without the rails of  FIG. 2 . 
         FIG. 4  is a cross-sectional view taken along  4 - 4  from  FIG. 3 , with the rails of  FIG. 2  included. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  schematically illustrates a powertrain  10  for an electric vehicle. Although depicted as a hybrid electric vehicle (HEV), it should be understood that the concepts described herein are not limited to HEVs and could extend to other electrified vehicles, including but not limited to, plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). 
     In one embodiment, the powertrain  10  is a 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 electric vehicle. 
     The engine  14 , which is an internal combustion engine in this example, 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 . 
     The generator  18  may be driven by 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 . 
     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 this example, 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 . 
     The motor  22  (i.e., the second electric machine) 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. 
     The battery pack  24  is an example type of electric vehicle battery assembly. The battery pack  24  may be a high voltage battery that is capable of outputting electrical power to operate the motor  22  and the generator  18 . Other types of energy storage devices and/or output devices can also be used with the electric vehicle. 
     Referring to  FIG. 2 , an example of the battery pack  24  includes a plurality of battery cells  60 . In this example, the cells  60  are prismatic cells. Each cell  60  include a first face  62  and a second face  64  opposite the first face  62 . The faces  62 ,  64  each have a length L 1  and the height H 1 . The cells  60  further include opposed sides  66 ,  68  having a width W 1  and a height H 1 . The cells  60  also include lower and upper surfaces  70 ,  72 , having the length L 1  and the width W 1 . 
     The cells  60  are held in place (i.e., secured), in this example, by a number of rails. As illustrated in  FIG. 2 , an upper rail  74  extends in a first direction D 1 . In this example, the first direction D 1  is parallel to the width W 1  of the cells  60  and is adjacent the upper surface  72  of the cells  60 . While only one upper rail  74  is illustrated, it should be understood that additional upper rails may be included. 
     Further, a side rail  76  extends along the sides of the cells  60  in a second direction D 2 . D 2 , in this example, is parallel to the height H 1  of the cells  60 . While only one side rail  76  is illustrated, there may be additional side rails. For instance, there may be one side rail  76  adjacent each side  66 ,  68  of each cell  60 . 
     The upper and side rails  74 ,  76  are made of a metallic material in some examples. Although not shown in  FIG. 2 , there may also be lower rail may support the cells  60  from below. 
     The cells  60  each include a current collector  78 . In this example, each cell  60  includes two current collectors  78 —one on each laterally outer side of the upper surface  72 . Current moves to and from the cells  60  through the current collector  78 . 
     Referring to  FIG. 3 , and with continuing reference to  FIG. 2 , a terminal  80  is secured directly to each current collector  78 . The terminal  80  is made of a conductive material, such as a metal, and in some examples is connected to a bus bar to transmit power for use in the powertrain  10 . 
     In this example, a terminal holder  82  is provided between the terminal  80  and the upper surface  72  of the cell  60 . The terminal holder  82  is made of a dielectric material, such as plastic, in one example. The terminal holder  82  in some cases is referred to as a “dielectric” or an “under-terminal dielectric.” As is known in this art, dielectric materials are electric insulators. This disclosure is not limited to any particular dielectric material. This disclosure also extends to other materials which may not be known as “dielectric” materials, but may have insulative properties. 
     In this example, the terminal holder  82  has a length L 2  and a width W 2 , each of which are larger than a corresponding length and width of the terminal  80 . Thus, in this example, the terminal  80  is provided entirely within a perimeter of the terminal holder  82 . 
     With joint reference to  FIGS. 3 and 4 , the example terminal holder  82  includes a main body portion  84  having a height H 2 . Note that the rails  74 ,  76  are shown in  FIG. 4 , but are excluded from  FIG. 3  for purposes of clarity. The main body portion  84  has an upper surface  86 , which is in direct contact with a lower surface  88  of the terminal  80 . The main body portion  84  further includes a lower surface  90 , which is in direct contact with the upper surface  72  of the cell  60 . The main body portion  84  electrically insulates the battery cell  60  from the terminal  80 . In this example, the height H 2  is at least 1.6 millimeters (0.063 inches), which ensures a proper level of insulation. 
     The illustrated terminal holder  82  further includes an upper rail protection portion  92  and a side rail protection portion  94 , each of which extend from the main body portion  84 . The upper rail and side rail protection portions  92 ,  94  are formed integrally with the main body portion  84  in one example. The terminal holder  82  may be injection molded—and thus integrally formed—to provide a seamless, continuous structure. This disclosure is not limited to injection molding, however. 
     With continued reference to  FIGS. 3 and 4 , the upper rail protection portion  92  includes a flange having first, second, and third legs  96 ,  97 ,  98 . As used herein, the term “flange” refers to any projection extending from the main body portion  84 . While three legs  96 ,  97 ,  98  are illustrated, other arrangements come within the scope of this disclosure. 
     In the illustrated example, the first leg  96  is arranged such that its length is parallel to the width W 3  of the upper rail  74 . Further, the first leg  96  is in contact with a side edge of the terminal  80 . The second leg  97  has a length perpendicular to the first leg  96 , and includes an inner surface  99  in contact with an outer edge  91  of the terminal  80 . The third leg  98  is provided on an opposite side of the terminal holder  82  than the first leg  96 , and substantially mirrors the first leg  96 . The second leg  97  spans between the first and third legs  96 ,  98 , and extends along an outer edge of the terminal holder  82 . 
     The uppermost surfaces of the first, second, and third legs  96 ,  97 ,  98  directly contact the upper rail  74  in this example. As illustrated in  FIG. 4 , uppermost surfaces  100 ,  102  of the first leg  96  and the second leg  97 , respectively, directly contact a lowermost surface  103  of the upper rail  74 . In this example, the first, second, and third legs  96 ,  97 ,  98  extend a height H 3  above the upper surface  89  of the terminal  80 . This height H 3  ensures that the upper rail protection portion  92  properly insulates the terminal  80  from the upper rail  74 . In this example, the height H 3  is at least 1.6 millimeters (0.063 inches). 
     The side rail protection portion  94 , in this example, is provided by the portion of the terminal holder  84  that extends beyond (e.g., overhangs) the side  66 . In this example the terminal holder extends beyond the side  66  of the cell  60  by a spacing S 1 . 
     The side rail protection portion  94  is provided in part by a flange  104 , which extends downward, by a distance illustrated as height H 4 , from a portion of the lower surface  90  of the main body portion  84 . Further, the flange  104  has an inner surface  106  that directly contacts the side  66  of the cell  60 . The flange  104  also has an outer surface  108 , which directly contacts an inner surface  110  of the side rail  76 . 
     The flange  104  has a thickness equal to the spacing S 1 , which ensures proper insulation between the side rail  76  and the cell  60 . In this example, the spacing S 1  is at least 1.6 millimeters (0.063 inches). In addition to the flange  104 , the side rail  76  is also in direct contact with an outer surface  112  of the main body portion  84 , and an outer surface of the second leg  97 . 
     The terminal holder  82  provides proper electrical insulation between the cells  60  and the adjacent structures, reducing the likelihood of a short. Further, the terminal holder  82  eliminates the need for a separate insulating structure, such as a dedicated rail cover, between the cells  60  and the rails  74 ,  76 . Accordingly, the disclosed arrangement reduces manufacturing costs and other complications, such as assembly time, associated with additional components. 
     It should be understood that terms such as “above,” “below,” “upward,” “downward,” “upper,” “lower,” “inner,” and “outer” are used above with reference to the normal orientation of the battery pack  24  and the cells  60  as used within a vehicle during operation. These terms are used for purposes of explanation, and should not be considered otherwise limiting. 
     Although the different examples have the specific components shown in the illustrations, embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples. 
     One of ordinary skill in this art would understand that the above-described embodiments are exemplary and non-limiting. That is, modifications of this disclosure would come within the scope of the claims. Accordingly, the following claims should be studied to determine their true scope and content.