Abstract:
A method and apparatus provide an electrical splice between different high-voltage components in a high-voltage propelled vehicle (HVPV), which enables a daisy-chain or series connection of the components. The method includes connecting a first end of a cable to a first component, a second end of the cable to a high-voltage bus bar within a second component to form a splice, and using the outer housings of the components to provide an environmental seal and electromagnetic capability (EMC) shield for the splice, rather than providing such a splice within a dedicated or shared power distribution box. A ring terminal connects to an end of a cable by a press-fitting process or a soldering process. The components can be an energy storage system (ESS), a power inverter module (PIM), an air conditioning control module (ACCM), an auxiliary power module (APM), a power steering controller, and an electrical motor/generator.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a method for electrically connecting or splicing a pair of high-voltage cables within a high-voltage vehicle component aboard a vehicle. 
       BACKGROUND OF THE INVENTION 
       [0002]    In a high-voltage propelled vehicle (HVPV), such as a hybrid-electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a fuel cell electric vehicle (FCEV), or a purely electric vehicle (EV), a relatively high-voltage power supply or energy storage system (ESS), for example a battery pack or other electrochemical energy storage device, provides a source of at least a portion of the electrical power required for propelling the vehicle. An engine or fuel cell can shut off or selectively power down when the vehicle is idling or at a standstill in order to further conserve fuel, and/or the vehicle can run entirely on electrical power provided by the ESS, depending on the particular design of the vehicle. 
         [0003]    To provide sufficient electrical power for partially or fully propelling the vehicle, as well as to energize various high-voltage components connected to the ESS aboard the vehicle, the ESS contains or stores a relatively high potential energy or voltage, typically on the order of 60 to 300 volts or more. Common high-voltage components used aboard an HVPV can include, for example, one or more electric motor/generators, as well as an air conditioning control module (ACCM), a power steering controller, a power inverter module (PIM), an auxiliary power module (APM), and/or other relatively high-voltage devices. 
         [0004]    The ESS delivers electrical currents of approximately 75 to 100 amps or more, which are conducted, transmitted, or routed through a dedicated high-voltage circuit using a high-voltage bus having a positively charged rail and a negatively charged rail. A separate power distribution box (PDB), or alternately a PDB that is integrally constructed with one of the various high-voltage components, is ordinarily used to provide high-voltage power distribution functionality aboard the vehicle, as effective direct high-voltage cable splicing methods, such as are commonly used to splice low-voltage cables or wires such as within a 12V system aboard a vehicle, are generally impracticable. By integrating the PDB function and structure with that of one of the high-voltage components, the total number of components may be reduced. However, such an integrated component has additional complexity and limited interchangeability across different vehicle models and platforms. 
         [0005]    Within the high-voltage component having PDB functionality, the electrical connection is ordinarily made using standard electrical cables and a bus bar having a relatively complex and geometrically offset configuration. Other high-voltage components receive dedicated power lines or cables from the high-voltage component having the integral PDB. While such designs provide certain advantages, they may be less than optimal for various manufacturing, cost-related, and packaging purposes. 
       SUMMARY OF THE INVENTION 
       [0006]    Accordingly, a method is provided for splicing high-voltage electrical cables within a high-voltage component of a vehicle. An outer housing of each of the interconnected components provides both an environmental seal and an electromagnetic capability (EMC) shield protecting the splice. The method includes connecting a first electrical cable from a first high-voltage component to a high-voltage bus bar of a second high-voltage component. 
         [0007]    When more than two components are used, the method includes connecting each of the components in series, using the outer housings of each component to provide the necessary environmental seals and EMC shielding of the splices contained within each of the outer housings. The connection to the bus bar is, in one embodiment, made using a ring terminal, which can be press-fitted or soldered to a conductor portion of the cable. 
         [0008]    A high-voltage power distribution network for a vehicle includes an energy storage system (ESS), a first and a second high-voltage component each having an outer housing and a high-voltage bus bar positioned within the respective housing, and a pair of cables. A first cable connects the ESS to the bus bar of the first component, and a second cable connects the bus bar of the first component to the bus bar of the second component. Each of the outer housings provide an environmental seal and an EMC shield to the electrical connection or splice contained within. The high-voltage components can be, but are not limited to, a power inverter module (PIM), an air conditioning control module (ACCM), an auxiliary power module (APM), a power steering controller, and/or a motor/generator. 
         [0009]    The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a schematic illustration of a prior art power distribution network aboard a vehicle; 
           [0011]      FIG. 2  is a schematic illustration of another prior art power distribution network; 
           [0012]      FIG. 3  is a schematic illustration of a series or daisy-chained power distribution network in accordance with the invention; 
           [0013]      FIG. 4A  is a cross sectional side view of a representative high-voltage cable assembly usable with the power distribution network of  FIG. 3 ; 
           [0014]      FIG. 4B  is a cross-sectional side view of a high-voltage cable usable with the power distribution network of  FIG. 3  and the cable assemblies of  FIGS. 4A ,  5 , and  6 ; 
           [0015]      FIG. 5  is a cross-sectional side view of the high-voltage cable assembly shown in  FIG. 4  when connected to a high-voltage vehicle component; and 
           [0016]      FIG. 6  is cross-sectional side view of another embodiment of the high-voltage cable assembly shown in  FIG. 5 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]    Referring to the drawings, wherein like reference numbers refer to like components, and beginning with the prior art  FIG. 1 , a representative power distribution network  10  is typically configured for supplying high-voltage electrical energy to various components  16 ,  16 A, and/or  16 B aboard a vehicle (not shown) using a dedicated power distribution box (DB)  14 , as described above. The network  10  includes an energy storage system (ESS)  12  which is electrically connected to the components  16 ,  16 A, and  16 B (also labeled A, B, and C, respectively) via suitable lengths of high-voltage cable  11  (see  FIG. 4B ). 
         [0018]    The ESS  12  can be configured as one or more batteries, such as nickel cadmium, lithium ion, or other suitable rechargeable battery device, although other electrical and/or electrochemical devices having the ability to alternately store and deliver electrical power to the components  16 ,  16 A, and/or  16 B as needed may also be used within the scope of the invention. The ESS  12  can be sized based on the required functions which the ESS  12  is expected to energize or support, including any regenerative braking requirements or propulsion requirements. The ESS  12  supplies high-voltage electrical power of approximately 60 to 300 volts, or more, ordinarily as a direct current voltage (VDC), although those of ordinary skill in the art will recognize that an alternating current voltage (VAC) may also be used. The electrical current delivered within the network  10  is generally approximately 75 to 100 amps, although other amperages may be used within the scope of the invention depending on the particular design of the vehicle (not shown) and network  10 . 
         [0019]    In the exemplary prior art network  10  of  FIG. 1 , the distribution box  14  is a separate component, with a cable  11  from the ESS  12  being electrically connected to a high-voltage bus bar (not shown) positioned within the distribution box  14 . Cables  11  then connect the distribution box  14  to each of the various components  16 ,  16 A, and  16 B separately. That is, each of the components  16 ,  16 A, and  16 B has a separate connection or input into the distribution box  14 . Use of a dedicated distribution box  14  may be less than optimal for various operational and economic reasons. Therefore, in accordance with the present invention as shown in  FIGS. 3-6  described below, the distribution box  14  shown in the prior art configuration of  FIG. 1  can be eliminated by splicing the cables  11  within the components  16 ,  16 A, and  16 B, in order to achieve a simplified series or daisy-chain power distribution configuration (see  FIG. 3 ), and to therefore provide a more optimally distributed electrical power within the vehicle (not shown). 
         [0020]    The high-voltage component  16 , or component A, is typically configured as a power inverter module or PIM, which is operable for receiving DC voltage from the ESS  12  and for providing AC current to one or more motor/generators, which could be either or both of the components  16 A and/or  16 B (component B and C, respectively) in  FIG. 2 . The component  16  can also be configured to include motor control logic needed to control the motor/generators, if either of the components  16 A and  16 B is so configured. When configured as an electrical motor, the components  16 A or  16 B can draw electrical energy from the ESS  12 , and when operating as an electrical generator, the components  16 A or  16 B can generate electrical energy for storage within the ESS  12 . 
         [0021]    Referring to  FIG. 2 , a representative network  10 A shows another prior-art configuration in which the distribution box  14  combines with one of the components  16 ,  16 A, or  16 B, into a common or integrated distribution/component  116 . Cables  11  leading from the common distribution/component  116  feed into each of the components  16 A and/or  16 B separately, or additional high-voltage components (not shown), as needed. However, the respective configurations of  FIGS. 1 and 2  include a distribution box  14  ( FIG. 1 ) or a common distribution/component  116  ( FIG. 2 ), which still requires separate connections to each of the components  16 A,  16 B connected thereto. As will now be explained with reference to the remaining figures, the distribution box  14  or common distribution/component  116  can be eliminated using a daisy-chain configuration enabled by the present invention, as will now be explained with reference to  FIG. 3 . 
         [0022]    Referring to  FIG. 3 , and in accordance with the invention, a network  10 B is provided in which the components  16 ,  16 A, and/or  16 B each have a single inlet port and a single outlet port are connected in series or “daisy-chained” using various lengths of the cables  11 . In this manner, the housings  40  (see  FIGS. 5 and 6 ) of the various components provide the environmental or weather seal as well as the electromagnetic compatibility (EMC) shield required for protecting the high-voltage electrical connection or splice within each of the housings  40 , as will now be described with reference to  FIGS. 4A through 6 . 
         [0023]    Referring to  FIG. 4A , a wiring harness or an electrical cable assembly  20  has a pair of cables  11 . As shown in  FIG. 4B , each cable  11  contains a conductive wire or stranded wires, referred to hereinafter simply as the conductor  28 , which is enclosed or contained within a dielectric inner insulating coating or insulator  29 B, such as polyethylene, rubber, fluorocarbon, or another suitable dielectric or insulating material. A jacket or shield  27 , such as woven nylon or other suitable material, is disposed between the insulator  29 B and an outer insulator  29 A. In  FIG. 4A , one of the cables  11  can be an inlet cable routed from the ESS  12  (see  FIGS. 1 ,  2 , and  3 ) or from another of the high-voltage components  16 ,  16 A, or  16 B, while the other cable  11  can be an outlet cable routed in series to a different one of the components  16 ,  16 A, or  16 B (see  FIG. 3 ). 
         [0024]    Each of the cables  11  contains a conductor  28 , as explained above with reference to  FIG. 4A , with the shield  27  and the conductor  28  being inserted through an opening  41  formed or otherwise provided in a shield plate  26 . The shield plate  26  is constructed of aluminum or another suitable material. Each of the wires  28  are connected to a respective one of a pair of terminals  30  and  30 A, such as ring terminals or other electrical terminals, depending on the position of the cable  11  to which the wire is connected. The terminals  30 ,  30 A, which can be a single stamped piece of tin-plated steel or other suitable material shaped, sized, or otherwise configured as needed depending on the number of cables  11  connected thereto, connect to a high-voltage bus bar  48  (see  FIGS. 5 and 6 ) within the component  16  (see  FIGS. 5 and 6 ), as will be discussed below with reference to  FIGS. 5 and 6 . 
         [0025]    Referring to  FIG. 5 , the shield plate  26  of the cable assembly  20  is constructed of aluminum or other suitable material providing sufficient electromagnetic compatibility (EMC) shielding capability to the component  16 . The shield plate  26  is shaped and/or sized as needed depending on the size of an opening  50  formed or provided in a housing  40  of the component  16 . The housing  40  can be constructed of a rigid but lightweight material such as cast aluminum, with the shield plate  26  being rigidly or positively connected to the housing  40  to thereby cover the opening  50 . In this manner, the shield plate  26  provides an additional or supplemental environmental seal to the component  16  by sealing the opening  50 , with the housing  40  (see  FIGS. 5 and 6 ) providing the main environmental sealing and EMC shielding required for the electrical splice or connection within the housing  40 . The shield plate  26  can be connected to the housing using any suitable device or method, such as by using threaded fasteners  36  in the embodiment shown in  FIG. 5 . 
         [0026]    An adaptor  24 , such as metal, copper, or aluminum, circumscribes the shield  27  (see  FIG. 4B ) and is positioned adjacent to the shield plate  26  to further provide a sufficient environmental seal between the shield  27  and the shield plate  26 . The terminals  30  and/or  30 A, which can be a single part or a single terminal  30  as shown in  FIG. 6 , are directly connected to the conductors  28 , such as by using a press-fit and/or a soldering process, or other suitable method, that ensures sufficient electrical conductivity, strength, and durability of the electrical connection. To further retain the cables  11  to the shield plate  26  prior to installation or connection to a component  16 , a metal boss (not shown) may be used on one side of the shield plate  26 , which can be squeezed or compressed against the cables  11  to connect or retain a perimeter or circumference of the cables  11  and hold the cables  11  in place. Alternately, plastic or adhesive (not shown) may be used between the cables  11  and the shield plate  26 , or heat-shrink tubing (not shown) may be used, in order to ensure that the cable assembly  20  remains intact as a single assembly or part number during transit, as well as during the vehicle manufacturing process. Once so attached, the terminals  30 ,  30 A are electrically connected to the bus bar  48  using a screw, bolt, or other fastener  35 . 
         [0027]    Referring to  FIG. 6 , an embodiment of the cable assembly  20  of  FIGS. 4 and 5  is shown as a cable assembly  120 , with the cable assembly  120  providing an end of the daisy-chain configuration shown in  FIG. 3 . A single terminal  30 A is used to connect the cable  11  to the bus bar  48  as described above. Such a configuration might be used when, for example, the ESS  12  (see  FIGS. 1 ,  2 , and  3 ) is connected to a single component  16 , which is not then electrically connected with another component  16 A or  16 B (see  FIG. 3 ), or when the component  16  is the last component in a series of interconnected or spliced components. 
         [0028]    In accordance with the description set forth hereinabove, and referring to  FIGS. 3-6 , a method is provided for forming an electrical splice between a first high-voltage component, such as a high-voltage energy storage system (ESS) or one of the various high-voltage components  16 ,  16 A, or  16 B discussed above, and a bus bar  48  positioned within each of the components  16 ,  16 A, and  16 B. To provide such a splice, a first end of a cable  11  is connected to the ESS  12  (see  FIG. 1 ), and then the other end of the cable  11  is inserted or passed through the opening  50  (see  FIGS. 5 and 6 ) of the housing  40 . The cable  11  is then electrically connected to the bus bar  48  within the housing  40 , and the shield plate  26  is connected to the housing  50 , thus closing out the opening  50 . The housing  40 , and to a lesser extent the shield plate  26 , provide the required environmental and EMC shielding capability for the splice. As discussed above, a terminal  30 A (see  FIG. 6 ) or  30 A,  30 B (see  FIGS. 4A and 5 ) can be used to connect the cable  11  to the bus bar  48 . 
         [0029]    In this manner, some level of design complexity is transferred to the cable harness or cable assembly  20  from the relatively expensive high-voltage components  16 ,  16 A, and  16 B. Doing so potentially increases the opportunity to reuse the components  16 ,  16 A, and/or  16 B across different vehicle platforms without having to redesign any major components. Additionally, by transferring the complexity of the electrical connection from the bus bar  48  located within the component  16  to the cable assembly  20 , any required clearance within the housing  40  is thereby reduced, thus saving valuable packaging space. The transfer of complexity to the cable assembly  20  is not expected to pose a significant obstacle in terms of additional pieces or required part numbers, as at least some features of the cabling used within various vehicles, such as length of the cables  11 , is frequently different across the different vehicle platforms, thus already requiring unique part numbering. 
         [0030]    While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.