Abstract:
An example electric vehicle component includes a current sensor shield that blocks magnetic fields of a contactor from influencing a current sensor. An example method of improving current sensor measurements includes blocking magnetic fields moving from a contactor toward the current sensor.

Description:
BACKGROUND 
       [0001]    This disclosure relates generally to shielding components of an electrified vehicle and, more particularly, shielding a sensor, such as a current sensor. 
         [0002]    Example vehicles include hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). Generally, hybrid vehicles differ from conventional motor vehicles because hybrid vehicles are selectively driven using a battery-powered electric machine. Conventional motor vehicles, by contrast, rely exclusively on an internal combustion engine to drive the vehicle. 
         [0003]    Electric vehicles often include various sensors. One such sensor, a current sensor, measures current. Current measurements from the current sensor can be used to, for example, help determine a state of charge for a battery of the electric vehicle. Inaccurate sensor measurements are undesirable. 
       SUMMARY 
       [0004]    An electric vehicle component according to an exemplary aspect of the present disclosure includes, among other things, a current sensor shield that blocks magnetic fields of a contactor from influencing a current sensor. 
         [0005]    In a further non-limiting embodiment of the foregoing component, the current sensor shield extends directly from a bus bar that electrically connects a first component of an electric vehicle to a second component of the electric vehicle. 
         [0006]    In a further non-limiting embodiment of any of the foregoing components, the current sensor shield and the bus bar are portions of a common continuous structure. 
         [0007]    In a further non-limiting embodiment of any of the foregoing components, the current sensor shield is a flange of the bus bar. 
         [0008]    In a further non-limiting embodiment of any of the foregoing components, the flange extends transversely from a primary portion of the bus bar. 
         [0009]    In a further non-limiting embodiment of any of the foregoing components, the flange is spaced apart from both the contactor and the current sensor. 
         [0010]    In a further non-limiting embodiment of any of the foregoing components, the flange is a folded portion of the bus bar. 
         [0011]    In a further non-limiting embodiment of any of the foregoing components, the flange and the bus bar comprise copper. 
         [0012]    In a further non-limiting embodiment of any of the foregoing components, the current sensor shield is housed within the contactor. 
         [0013]    In a further non-limiting embodiment of any of the foregoing components, the current sensor shield is disposed about at least three distinct sides of a coil of the contactor. 
         [0014]    An electric vehicle assembly according to another exemplary aspect of the present disclosure includes a contactor, a bus bar electrically connected to the contactor, a current sensor to measure current on the bus bar, and a current sensor shield. The contactor generates magnetic fields and the current sensor shield blocks at least a portion of the magnetic fields from reaching the contactor. 
         [0015]    In a further non-limiting embodiment of the foregoing assembly, a magnetic field emanates from the contactor toward the current sensor along a path, and the current sensor shield is disposed within the path. 
         [0016]    In a further non-limiting embodiment of any of the foregoing assemblies, the path is a linear path. 
         [0017]    In a further non-limiting embodiment of any of the foregoing assemblies, the contactor, bus bar, current sensor, and current sensor shield are housed within a bussed electric center (BEC). 
         [0018]    In a further non-limiting embodiment of any of the foregoing assemblies, the contactor selectively breaks an electrical connection between a load and a high voltage battery of an electric vehicle. 
         [0019]    In a further non-limiting embodiment of any of the foregoing assemblies, the current sensor shield is a flange extending directly from the bus bar. 
         [0020]    In a further non-limiting embodiment of any of the foregoing assemblies, the current sensor shield is housed within the contactor. 
         [0021]    A method of improving current sensor measurements according to yet another example aspect of the present disclosure includes, among other things, blocking magnetic fields moving from a coil of a contactor toward the current sensor. 
         [0022]    In a further non-limiting embodiment of the foregoing method, the method includes blocking using a flange of a bus bar that is spaced from both the contactor and the current sensor. 
         [0023]    In a further non-limiting embodiment of any of the foregoing methods, the method includes blocking by covering at least three sides of a coil within the contactor with a metallic plate. 
         [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. 
     
    
     
       DESCRIPTION OF THE FIGURES 
         [0025]    The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description. The figures that accompany the detailed description can be briefly described as follows: 
           [0026]      FIG. 1  shows a highly schematic view of an example hybrid powertrain for an electric vehicle. 
           [0027]      FIG. 2  shows a top view of a portion of a bussed electrical center of the powertrain of  FIG. 1 . 
           [0028]      FIG. 3  shows a side view of the portion of  FIG. 2 . 
           [0029]      FIG. 4  shows another example current sensor shield. 
           [0030]      FIG. 5  shows yet another example current sensor shield. 
           [0031]      FIG. 6A  shows a top view of yet another example sensor shield prior to folding. 
           [0032]      FIG. 6B  shows the sensor shield of  FIG. 6A  after folding. 
           [0033]      FIG. 7  shows a perspective view of yet another example current sensor shield. 
           [0034]      FIG. 8  shows the current sensor shield of  FIG. 6  incorporated into a contactor. 
       
    
    
     DETAILED DESCRIPTION 
       [0035]    Referring to  FIG. 1 , an example hybrid powertrain  10  for an electric vehicle includes a battery  14 , an electric machine  18 , and an internal combustion engine  22 . The example powertrain  10  is incorporated into a hybrid electric vehicle (HEV). It should be understood, however, that the concepts described herein are not limited to HEVs and could extend to other vehicles including, but not limited to, plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), etc. The battery  14  is a relatively high voltage battery in this example. 
         [0036]    In an example embodiment, the powertrain  10  employs a first drive system and a second drive system. The first drive system includes a combination of at least the electric machine  18  and the battery  14 . The first drive system can thus be considered an electric drive system of the powertrain  10 . The second drive system includes a combination of the internal combustion engine  22  and the electric machine  18 . 
         [0037]    The first and second drive systems generate torque to drive one or more sets of vehicle drive wheels  26  through a transmission gearbox  30 . When the first drive system is employed, a disconnect clutch (not shown) may operably disconnect the internal combustion engine  22  from the remaining portions of the powertrain  10 . When the second drive system is employed, the disconnect clutch engages to operably connect the internal combustion engine  22  to the remaining portions of the powertrain  10 . The disconnect clutch could remain engaged when the first or second drive system is employed to permit the internal combustion engine  22  to drive the electric machine  18  to charge the battery  14 . 
         [0038]    The electric machine  18  is a combined motor-generator in this example. In other examples, the electric machine includes a motor and a generator that is separate from the motor. 
         [0039]    The powertrain  10  includes a bussed electrical center (BEC)  34  includes at least one contactor  38  and a current sensor  42 . The contactor  38  is essentially a relay having a coil. The contactor  38  can be used to selectively break an electrical connection between the battery  14  and electrical loads associated with other portions of the powertrain  10 . The contactor  38  could be a precharge contactor or one (of two or more) primary contactors within the BEC  34 . The contactor could also be a charger contactor. 
         [0040]    The current sensor  42  is used to measures current within the BEC  34 . The current measurements from the current sensor  42  may be used to determine a state of charge of the battery  14 , for example. The current sensor  42  continually senses current during operation. 
         [0041]    The example contactor  38  generates magnetic fields. Measurements taken by the sensor  42  can be influenced by magnetic fields. Essentially, the current driving the contactor  38  can be sensed by the current sensor  42 , which creates an offset or other type of error in the measured current. 
         [0042]    The example BEC  34  includes a shield  46  to block at least some of the magnetic fields propagating toward the sensor  42  from the contactor  38  from reaching the sensor  42 . The shield  46  lessens errors in the readings of the current sensor  42  without compromising packaging. 
         [0043]    Referring now to  FIGS. 2 and 3  with continued reference to  FIG. 1 , the BEC  34  includes a bus bar  50  utilized to carry current. In this example, the bus bar  50  carries current between a first electrical component  52  and a second electrical component  52 . Examples of the first electrical component  52  include a traction battery, safety disconnect, or fuse. Examples of the second component include a charger, fan, or a pump, and/or A/C Compressor driven by the HV Battery. Vehicle applications, and thus electrical components, can vary. 
         [0044]    The bus bar  50  mounts to a floor  54  of the BEC  34 . The contactor  38  and the current sensor  42  are both electrically connected to the bus bar  50 . 
         [0045]    As shown, the current sensor  42  is in relatively close proximity to the contactor  38 . The example current sensor  42  receives a tab  56  extending upwardly from the bus bar  50 . The current sensor  42  includes an aperture that receives the tab  56 . During operation, the current sensor  42  senses current on the tab  56  and thus the current on the bus bar  50 . The current sensor  42  has a ferrous core and hall effect sensors to sense current. 
         [0046]    Magnetic fields F emanate from the contactor  38  during operation. Some of the magnetic fields F move directly toward the contactor  38  along a linear path. Magnetic fields F can undesirably influence measurements taken by the current sensor  42 . The measurements taken by the current sensor  42  may have an offset or some other type of error in the measured current, for example. 
         [0047]    The shield  46  blocks at least some of the magnetic fields F from reaching the sensor  42 . The shield  46  significantly impedes the capability of the magnetic field F to pass from the contactor  38  to the current sensor  42 . 
         [0048]    In this example, the shield  46  is an upwardly extending flange disposed between the contactor  38  and the sensor  42 , and spaced apart from both the contactor  38  and the sensor  42 . The example shield  46  extends upwardly from a primary portion  58  of the bus bar  50 . The primary portion  58  of the bus bar  50  is a planar portion of the bus bar  50  interfacing directly with the floor  54  or housing of the BEC  34 . 
         [0049]    In this example, the shield  46  and the bus bar  50  are portions of the same continuous structure. That is, the shield  46  is formed together with the bus bar  50 . 
         [0050]    The bus bar  50  and the shield  46  both comprises copper in this example. Copper facilitates carrying current. 
         [0051]    In another example, the bus bar  50 , the shield  46 , or both, could be an alloy or a multilayer material including a layer of aluminum, for example, covered by a layer of another material. In a multilayer example, multiple sheets of various materials could be connected or bonded. The multilayer example of the bus bar  50  may include a copper sheet and sheets of other alloys or metals and aluminum. The copper sheet could be a plating of copper on another material. 
         [0052]    Referring now to  FIG. 4 , an example shield  46   a  is a folded portion of a bus bar  50   a  formed from a planar sheet of material that has been is folded over itself. Since the shield  46   a  is essentially the bus bar  50   a  folded a single time, a thickness 2T of the shield  46   a  is about twice a thickness T of the bus bar  50   a . Other shields may be folded more than once. 
         [0053]    One of many types of manufacturing processes may be used to fold the bus bar  50 A to form the shield  46 A to protect the current sensor  42 . 
         [0054]    Referring now to  FIG. 5  with continued reference to  FIG. 4 , another example shield  46   b  includes a flange  60  extending directly from a primary portion  58   b  of the bus bar  50   b . A second flange  64  extends from the flange  60  to cover a surface  68  of the sensor  42  facing upwards and away from the primary portion  58   b  of a bus bar  50   b . Since the flange  60  extends across the surface  68  to wrap around the current sensor  42 , the shield  46   b  may impede the magnetic field F more effectively than the shield  46   a.    
         [0055]    The shield  46   b  could be folded in a manner similar to the shield  46   a . Alternatively, the shield  46   b  could be formed separately from the primary portion of the bus bar  50   b  and secured to the bus bar  50   b  with a weld, for example, or another fold. 
         [0056]    The extension E could be an extrusion, such as a deep draw extrusion, from the bus bar  50   c  in some examples. 
         [0057]    Referring now to  FIGS. 6A and 6B , another example shield  46   c  of a bus bar  50   c  is formed from an extension off of a side of the bus bar  50   c . The extension E is folded along fold lines L 1  and L 2 . The folds are ninety degree folds in this example. The extension E is sliced off of the bus bar  50   c  in some examples. 
         [0058]    The bus bar  50   c  may further include a stabilization tab  68  to help secure the sensor (not shown in this example). 
         [0059]    Referring now to  FIGS. 7 and 8 , yet another example shield  46   d  is utilized more closely to a contactor  38   a  than the shields  46 - 46   c . In this example, the shield  46   d  is housed within the contactor  38   a  between a housing  70  and a coil  74 . The shield  46   d  could also be outside the housing  70  in some examples. The magnetic fields propagate from the coil  74 . This positioning of the shield  46   d  thus provides shielding. 
         [0060]    The shield  46   d  covers at least three distinct outwardly facing sides S 1 , S 2 , S 3 , of the coil  74  within the contactor  38   a . Side S 1  faces in an opposite direction from side S 2 . The shield  46   c  extends continuously from side S 1  to side S 2  to side S 3 . 
         [0061]    The housing  70  holds the shield  46   d  in position. The housing  70  may be a plastic housing that is welded. 
         [0062]    In the prior art, contactors have included metallic structures, like steel frames, within a housing, yet these metallic structures have not provided significant and appropriate shielding of magnetic fields F emanating from the coils  74  of the contactor  38 . The shield  46   d  can be, in some examples, a continuation of steel frame within the housing  70  that provides desirable shielding by covering at least three sides of the coil  74 . 
         [0063]    Any of the above-described example shields could be made thinner to reduce weight and conserve material. The shields could also include apertures to reduce weight. The apertures could be sized such that the shields still appropriately block the fields F. 
         [0064]    The above-described example shields could also be encased in an insulating cover or coating to protect against shorting against portions of the BEC. 
         [0065]    The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. Thus, the scope of legal protection given to this disclosure can only be determined by studying the following claims.