Abstract:
A fuse assembly according to an exemplary aspect of the present disclosure includes, among other things, a housing, a fuse received within a receptacle of the housing and a retention device configured to retain the fuse within the receptacle and cover a conductive surface of the fuse.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates to a fuse assembly for use within electrical systems of an electrified vehicle. 
       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 propel the vehicle. 
         [0003]    Electrified vehicles include multiple electrical systems for distributing electric power throughout the vehicle. Fuses are used in many such electrical systems, including within a high voltage battery pack that is employed to selectively power the electrified vehicle. Fuses are designed to open when an abnormality occurs in the electrical system in order to interrupt the circuit. Fuses therefore act as sacrificial devices for protecting the electrical systems from damage during circuit overload conditions. 
       SUMMARY 
       [0004]    A fuse assembly according to an exemplary aspect of the present disclosure includes, among other things, a housing, a fuse received within a receptacle of the housing and a retention device configured to retain the fuse within the receptacle and cover a conductive surface of the fuse. 
         [0005]    In a further non-limiting embodiment of the foregoing fuse assembly, the retention device includes a first retention finger and a second retention finger. 
         [0006]    In a further non-limiting embodiment of either of the foregoing fuse assemblies, the first retention finger and the second retention finger are flexible between a first position in which the first retention finger is proximate to the second retention finger and a second position in which the first retention finger and the second retention finger are spread apart from one another. 
         [0007]    In a further non-limiting embodiment of any of the foregoing fuse assemblies, the conductive surface is part of an end cap or a terminal of the fuse. 
         [0008]    In a further non-limiting embodiment of any of the foregoing fuse assemblies, a pull tab is connected to the fuse. 
         [0009]    A battery pack according to another exemplary aspect of the present disclosure includes, among other things, a housing, a fuse received within the housing and a first retention finger and a second retention finger each flexible between a first position and a second position relative to the fuse, the first retention feature and the second retention feature cooperating to cover a conductive surface of the fuse in the first position. 
         [0010]    In a further non-limiting embodiment of the foregoing battery pack, the housing is positioned adjacent to at least one grouping of battery cells. 
         [0011]    In a further non-limiting embodiment of either of the foregoing battery packs, the first retention finger is proximate to the second retention finger in the first position and the first retention finger and the second retention finger are spread apart from one another in the second position. 
         [0012]    In a further non-limiting embodiment of any of the foregoing battery packs, each of the first retention finger and the second retention finger include a lead-in ramp configured to guide the fuse between the first retention finger and the second retention feature. 
         [0013]    In a further non-limiting embodiment of any of the foregoing battery packs, the battery pack includes a beveled surface on an underside of a head of each of the first retention feature and the second retention feature. 
         [0014]    In a further non-limiting embodiment of any of the foregoing battery packs, the first retention finger and the second retention finger extend upwardly from the housing between walls of the housing. 
         [0015]    In a further non-limiting embodiment of any of the foregoing battery packs, the battery pack includes a third retention finger and a fourth retention finger cooperating to cover a second conductive surface of the fuse. 
         [0016]    In a further non-limiting embodiment of any of the foregoing battery packs, a terminal of the fuse engages a mating terminal located within a receptacle of the housing. 
         [0017]    In a further non-limiting embodiment of any of the foregoing battery packs, a pull tab is connected to the fuse. 
         [0018]    In a further non-limiting embodiment of any of the foregoing battery packs, the pull tab includes a body attached to the fuse and an extension that extends from the body. 
         [0019]    A method according to another exemplary aspect of the present disclosure includes, among other things, positioning a fuse within a receptacle of a housing of an electrical system of an electrified vehicle such that a conductive surface of the fuse is substantially covered by a retention device of the housing. 
         [0020]    In a further non-limiting embodiment of the foregoing method, the electrical system is a battery pack of the electrified vehicle. 
         [0021]    In a further non-limiting embodiment of either of the foregoing methods, positioning the fuse includes moving the fuse along a lead-in ramp of the retention device. 
         [0022]    In a further non-limiting embodiment of any of the foregoing methods, the method includes spreading apart a first retention finger and a second retention finger of the retention device as the fuse is moved further toward a mating terminal housed in the receptacle. 
         [0023]    In a further non-limiting embodiment of any of the foregoing battery packs, the method includes moving the first retention finger and the second retention finger back toward one another after the fuse has engaged the mating 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 pack of an electrified vehicle. 
           [0028]      FIG. 3  illustrates a fuse. 
           [0029]      FIGS. 4A and 4B  illustrate a fuse assembly according to a first embodiment of this disclosure. 
           [0030]      FIGS. 5A, 5B, 5C and 5D  illustrate an exemplary fuse insertion method. 
           [0031]      FIGS. 6A and 6B  illustrate a fuse assembly according to a second embodiment of this disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    This disclosure details a fuse assembly for use within an electrical system. In one non-limiting embodiment, the fuse assembly is utilized within a high voltage battery pack of an electrified vehicle. The fuse assembly includes a housing and a fuse received within a receptacle of the housing. One or more retention devices retain the fuse within the receptacle and simultaneously cover a conductive surface of the fuse. In some embodiments, the retention devices include pairs of retention fingers that spread apart when the fuse is installed and spring back toward one another to cover the conductive services after the fuse is received within a mating terminal of the fuse assembly. These and other features are discussed in greater detail in the following paragraphs of this detailed description. 
         [0033]      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. 
         [0034]    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. 
         [0035]    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 . 
         [0036]    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 . 
         [0037]    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 . 
         [0038]    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 . 
         [0039]    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 . 
         [0040]    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. 
         [0041]    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. 
         [0042]      FIG. 2  schematically illustrates portions of a battery pack  24  of an electrified vehicle. For example, the battery pack  24  could be part of the electrified vehicle  12  of  FIG. 1  or any other vehicle. The battery pack  24  is one example of the many electrical systems that may be employed to distribute power throughout an electrified vehicle. 
         [0043]    The battery pack  24  includes a plurality of battery cells  56  for supplying electrical power to various electrical loads of the electrified vehicle  12 . The battery cells  56  may be stacked side-by-side along a longitudinal axis to construct one or more groupings of battery cells  56 , sometimes referred to as “cell stacks.” Spacers  58 , which can alternatively be referred to as separators or dividers, may be positioned between adjacent battery cells  56  of each grouping of battery cells  56 . The spacers  58  may include thermally resistant and electrically isolating plastics and/or foams. The battery cells  56  and the spacers  58  are together referred to as a battery array  60 . Two battery arrays  60  are shown in  FIG. 2 ; however, the battery pack  24  could include only a single battery array or greater than two battery arrays. 
         [0044]    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. 
         [0045]    An enclosure  62  generally surrounds the battery arrays  60  of the battery pack  24 . The enclosure  62  may include multiple walls that support, surround or otherwise house the components of the battery pack  24 . 
         [0046]    A housing  64  may be disposed inside the battery pack  24 . The housing  64  is positioned adjacent to the battery arrays  60  and could be mounted to one or more of the walls of the enclosure  62 . The specific arrangement of the housing  64  and the battery arrays  60  shown in  FIG. 2  is but one non-limiting example of how the various components of the battery pack  24  could be arranged and is not intended to limit this disclosure. In one non-limiting embodiment, the housing  64  is a fuse box or junction box that acts as the electrical center of the battery pack  24 . In another non-limiting embodiment, the housing  64  is a stand-alone fuse holder. 
         [0047]    One or more fuses  66  may be received by the housing  64 . A portion of the housing  64  is shown removed in  FIG. 2  to better illustrate the fuses  66 . Each fuse  66  is designed to open when an abnormality occurs within the electrical system, here the battery pack  24 . For example, the fuses  66  may act as sacrificial devices for interrupting a circuit to prevent damage to the electrical system during circuit overload conditions. 
         [0048]    An exemplary fuse  66  that could be employed for use within the battery pack  24  of  FIG. 2  or any other electrical system is illustrated in  FIG. 3 . In one non-limiting embodiment, the fuse  66  is a cylindrical, plug-in type fuse. However, other types of fuses could also benefit from the teachings of this disclosure. In another non-limiting embodiment, the fuse  66  is part of a high voltage load circuit (e.g., voltage rating of 250-600V). 
         [0049]    The fuse  66  includes a body  68 , end caps  70  disposed on opposing sides of the body  68 , and terminals  72  that extend from the end caps  70 . The body  68  of the fuse  66  may be made of a non-conductive material, such as plastic or glass, for example. The body  68  houses a fuse element (not shown) configured to open the circuit (e.g., blow) during current overload conditions. The terminals  72  may or may not be electrically connected to the end caps  70 . 
         [0050]    The end caps  70  are made of conductive materials, such as copper, aluminum, etc., and therefore include conductive surfaces  74 . In one non-limiting embodiment, current flows across the terminals  72  and over the conductive surfaces  74  of the end caps  70  as it passes through the fuse  66 . A relatively high voltage can be applied to the conductive surfaces  74  during certain conditions. It may be therefore be desirable to prevent human exposure to the conductive surfaces  74 , such as during a servicing event of the battery pack  24 . The remaining portion of this disclosure describe various retention devices that are configured to both retain the fuse  66  within the housing  64  and cover the conductive surfaces  74  or any other surfaces of the fuse  66  that may be subject to high voltages to prevent high voltage contact. 
         [0051]      FIGS. 4A and 4B  illustrate a fuse assembly  76  for use within the battery pack  24  or any other electrical system. The fuse assembly  76  includes a fuse  66  and a housing  64 . The housing  64  includes a receptacle  78  for receiving the fuse  66 . The receptacle  78  may be circumscribed by vertical walls  80  that protrude upwardly from the housing  64 . The terminals  72  of the fuse  66  are received within mating terminals  82  that are mounted within the receptacle  78 . 
         [0052]    The fuse assembly  76  may additionally include one or more retention devices  84  for retaining the fuse  66  within the receptacle  78 . The retention devices  84  could be an integral part of the housing  64  or could alternatively be separate devices that are mechanically mounted to the housing  64 . The retention devices  84  protrude upwardly from the housing  64  and may be disposed at a location between the vertical walls  80 . 
         [0053]    In one non-limiting embodiment, the retention devices  84  include pairs of retention fingers  88 A,  88 B located near opposing ends  85  of the receptacle  78 . However, the retention fingers  88 A,  88 B could be disposed along any portion of the receptacle  78 . The housing  64  may include four retention fingers, or two pairs of the retention fingers  88 A,  88 B. The retention fingers  88 A,  88 B are positioned on opposite sides of the fuse  66  once it is connected to the mating terminals  82  (see  FIG. 4A ). A relatively small gap  87  may optionally extend between the retention fingers  88 A,  88 B. The gap  87  is small enough to make it very difficult for a human finger  90  or other similarly sized object to make contact with the fuse  66  between the retention fingers  88 A,  88 B. 
         [0054]    The retention devices  84  of the fuse assembly  76  serve a dual purpose. First, the retention devices  84  retain the fuse  66  within the receptacle  78  and prevent the fuse  66  from backing out of the mating terminals  82 . Second, the retention devices  84  substantially cover the conductive surfaces  74  of the end caps  70  and terminals  72  of the fuse  66  or any other surface of the fuse  66  that may have high voltage on it. For example, in one non-limiting embodiment, the retention fingers  88 A,  88 B are configured to cover the conductive surfaces  74  once the fuse  66  is received within the receptacle  78  and the terminals  72  are connected to the mating terminal  82 . The retention fingers  88 A,  88 B therefore prevent a human finger  90  from coming into contact with the conductive surfaces  74  of the fuse  66 . 
         [0055]      FIGS. 5A-5D  schematically illustrate an exemplary method for inserting the fuse  66  into the receptacle  78  of the housing  64 . Referring first to  FIG. 5A , the fuse  66  is positioned above the receptacle  78  of the housing  64 . The fuse  66  is then moved toward the mating terminals  82  until the end caps  70  contact the retention fingers  88 A,  88 B, as shown in  FIG. 5B .  FIGS. 5A and 5B  both shown the retention fingers  88 A,  88 B positioned proximate to one another in a first position X. 
         [0056]    The retention fingers  88 A,  88 B are flexible and may include lead-in ramps  92  that help guide the fuse  66  into the receptacle  78 . For example, as shown in  FIG. 5C , the retention fingers  88 A,  88 B spread apart from one another as the end caps  70  (or fuse body  68 ) are guided along the lead-in ramps  92 . As the fuse  66  moves further toward the mating terminals  82 , the retention fingers  88 A,  88 B spread further apart to a second position X′ to permit the end caps  70  and/or the fuse body  68  of the fuse  66  to pass between the retention fingers  88 A,  88 B. Finally, as shown in  FIG. 5D , the spring fingers  88 A,  88 B may move back toward one another (i.e., move back to the first position X) to cover the conductive surfaces  74  of the fuse  66  once the terminals  72  of the fuse  66  have engaged the mating terminals  82 . 
         [0057]      FIGS. 6A and 6B  illustrate another exemplary fuse assembly  176 . The fuse assembly  176  is similar to the fuse assembly  76  of  FIGS. 4A and 4B  but additionally includes a pull tab  94  for selectively removing the fuse  66  from the receptacle  78  of the housing  64 . In one non-limiting embodiment, the pull tab  94  is a piece of tape with sufficient strength for disengaging the terminals  72  from the mating terminals  82  and removing the fuse  66  from between the retention fingers  88 A,  88 B. The pull tab  94  may include a body  96  that is wrapped around the body  68  of the fuse  66  (see  FIG. 6B ) and an extension  98  that extends from the body  96  and which may be tugged in a direction D 1  to remove the fuse  66 . 
         [0058]    In another non-limiting embodiment, the retention fingers  88 A,  88 B include beveled surfaces  99  (see  FIG. 6A ) that act as ramps to spread the retention fingers  88 A,  88 B apart as the pull tab  94  is used to remove the fuse  66  from the receptacle  78 . The beveled surfaces  99  may be located on an underside of a head  97  of each retention finger  88 A,  88 B. The beveled surfaces  99  may generally match the curvature of the end caps  70  or fuse body  68  of the fuse  66 , in one non-limiting embodiment. 
         [0059]    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. 
         [0060]    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. 
         [0061]    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.