Abstract:
In an electrical connector for an electric vehicle, the spring latch is not sealed; instead, the connector body has holes allowing water entering the spring latch mechanism to drain harmlessly out of the connector. A forward-facing LED or other light source acts as a flashlight. Once the connector is connected, the forward-facing LED is switched off, and a rear-facing LED or other light source is switched on to confirm that the connector is connected and capable of charging the vehicle. The connector is produced by overmolding in a three-layer configuration, where each layer is formed of a material having advantageous materials for that layer&#39;s position in the connector.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of U.S. Provisional Patent Application No. 61/430,456, filed Jan. 6, 2011, and U.S. Provisional Patent Application No. 61/482,459, filed May 4, 2011. The present application is also a continuation-in-part of U.S. Design patent application No. 29/382,230, filed Dec. 30, 2010, currently pending. The disclosures of the above-referenced applications are hereby incorporated by reference in their entireties into the present application. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is directed to an electrical connector for supplying power to an electric vehicle and more particularly to such a connector having improved resistance to water in the environment and improved user-friendliness. 
       DESCRIPTION OF RELATED ART 
       [0003]    Electric vehicles are increasingly receiving attention. These include plug-in hybrid vehicles such as the Chevrolet Volt and purely electric vehicles such as the Nissan Leaf. 
         [0004]    Electrical connectors for recharging the batteries of electric vehicles are standardized in North America by Society of Automotive Engineers (SAE) standard SAE J1772. Other applications, such as forklifts and industrial equipment, may also adopt that standard. 
         [0005]    According to that standard, the front of the connector has a standardized shape and five pins in a standardized layout, so that all connectors work with all electric vehicles. The five pins are two AC power pins, a ground pin, a proximity detection pin and a control pilot pin. Regarding the rest of the connector, the manufacturer of each connector has some discretion. Known connectors typically use spring latches to secure the connector to the vehicle during charging. 
         [0006]    Since such connectors are typically used outdoors, environmental considerations, such as water, must be taken into account. For example, water may get into the mechanism of the spring latch and cause corrosion or other degradation. The usual way to prevent such degradation is to use a rubber seal to protect the spring latch. However, seals fail. 
         [0007]    There are also the problems of using the connector at night, when the motorist may not be able to see properly, and of letting the motorist know when the connector has been fully and properly inserted. 
         [0008]    Moreover, known connectors are typically manufactured from multiple parts. As a consequence, they can be expensive to manufacture and prone to failure. 
         [0009]    To date, all solutions currently available in the Electric Vehicle (EV) market space are constructed from two halves (or clamshells) which are mechanically assembled with tamper-resistant fasteners such as Torx™ screws. The old or current SAE J1772 mechanically assembled connectors currently allow water to enter the handle assembly, leading an opportunity for ice and debris to become trapped. Additionally, the clamshells add a bulky appearance at the handle and overall body, which is driven by the additional mechanical features required to resist vehicle roll-over and crush requirements, as stated in UL 2251. These current devices are suitable for garage and indoor applications. When used outdoors, these clam-shell designs may exhibit shorter life cycles due to exposure to the elements. 
       SUMMARY OF THE INVENTION 
       [0010]    It is therefore an object of the invention to address the above concerns. 
         [0011]    It is another object of the invention to provide a low-cost, attractive, ergonomic and adaptable solution. 
         [0012]    To achieve the above and other objects, the present invention is directed to a connector having at least one of the following features. 
         [0013]    The spring latch is not sealed; instead, the connector body has holes allowing water entering the spring latch mechanism to drain harmlessly out of the connector. A forward-facing LED or other light source acts as a flashlight. Once the connector is connected, the forward-facing LED is switched off, and a rear-facing LED or other light source is switched on to confirm that the connector is connected and capable of charging the vehicle. 
         [0014]    The connector is produced by overmolding. For example, the connector can be produced in a three-layer configuration, with potting material, a premold, and a one-piece overmold. Each of the layers can be formed of a different material that gives it the properties needed for its location in the connector. The modular design allows for faster product updates and a common platform for product diversification. 
         [0015]    The above features can be combined in any way. 
         [0016]    The problem being solved by this invention is offering the EV (electric vehicle) market space (such as Original Equipment Manufacturers (OEM) and Electric Vehicle Supply Equipment (EVSE) manufacturers) a ruggedized and integrated overmolded SAE J1772 connector and cable assembly solution that offers reduced life-cycle costs and improved product reliability, and that also reduces the risks of tampering and vandalism associated with mechanical locking features and hardware (such as Torx™ Screws). This over-molded solution offers exceptional environmental protection from the extreme environmental elements which may include: water, ice, dust, ultra-violet rays, oils and automotive fluids. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    A preferred embodiment will be set forth in detail with reference to the drawings, in which: 
           [0018]      FIGS. 1-8  are various views of the connector according to the preferred embodiment and of various components thereof; and 
           [0019]      FIGS. 9A-21  are views showing steps in the production of the connector of  FIGS. 1-8 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0020]    A preferred embodiment will be set forth in detail with reference to the drawings, in which like reference numerals refer to like elements throughout. 
         [0021]    As shown in  FIGS. 1-8 , the connector  100  according to the preferred embodiment includes a connector front piece  102  with a plurality of pins  104 ,  106 ,  108 ,  110 ,  112 . In the preferred embodiment, the connector front piece  102  and the pins  104 - 112  follow the standard SAE J1772. The pins  104 - 112  are electrically connected to a cable  114  at a location which is sealed inside of the connector front piece  102  with potting  116 . A connector body  118  is formed over the connector front piece  102  and the cable  114  by a premold  120  and an overmold  122 . The premold  120  and the overmold  122  are formed with ridges  124 ,  126  to increase the strength of the connector body  118 . The connector body has a latch area  128  with a spring latch  130  having a pin  132  and a spring  134 . 
         [0022]    A first LED or other light  136  can be provided to act as a flashlight, so that the user can use the connector at night in situations of poor lighting. A second LED or other light  138  can be provided on the back to indicate when the proper electrical connection between the connector and the vehicle is achieved, at which time the first LED is switched off. Circuitry  140 , such as a printed circuit (PC) board to be described below, is provided for controlling the LED&#39;s. 
         [0023]    The latch area  128  does not have to be sealed against water. Instead, water entering the latch area  128  exits through holes  142 . As shown, there are three holes  142  on either side of the latch area  128 , extending through the overmold  122  and into the latch area  128 . The holes  142  are open to the latch area  128  at a bottom surface  144  of the latch area  128  so that there will be no places for the water to accumulate. However, any suitable number and configuration of holes can be used instead of, or in addition to, the holes shown. 
         [0024]    For example, in use in a rainy situation, rain water incident on the connector  100  enters the latch area  128  by flowing around the spring latch  130 . Instead of accumulating in the latch area  128 , the water exits the latch area  128  through the holes  142 . As noted above, the holes  142  are positioned relative to the bottom surface  144  of the latch area  128  so that all of the water drains out of the latch area  128  rather than forming puddles below the holes  142 . 
         [0025]    The holes  142  are shown as extending horizontally to facilitate overmolding. The left and right components of the mold used in the overmolding can have projections corresponding to the holes  142  and thus form the holes  142 . After the overmolding process, the left and right components are pulled off in a horizontal direction to pull the projections out of the holes  142  thus formed. However, the configuration of the holes  142  can be varied in accordance with various manufacturing techniques. For example, in different manufacturing techniques, the holes  142  could slope downwardly from the latch area  128  or even extend vertically downwardly from the latch area  128 . Moreover, holes  142  can be formed in any other suitable manner, e.g., by drilling. 
         [0026]    Still other configurations are possible. For example, the latch area  128  could have a bottom surface  144  that is flat or that is crowned to urge water out through the holes  142 . Also, while the holes  142  are shown as elongated, they could have any suitable shape, e.g., round. 
         [0027]    The preferred embodiment provides an overmolded, ruggedized, and robust high-amperage SAE J1772 connector assembly. The production of the preferred embodiment begins with an insert molded SAE J1772 10 amp through 90 amp connector, shown in  FIGS. 9A and 9B  as  146 , made of a polycarbonate material with a UL94 V-0 flame rating with an environmental (f1) ultra-violet rating and a relative thermal index (RTI) equal to or exceeding 100 for electrical and physical impact and strength characteristics, as specified by the standard UL 2251. 
         [0028]    The SAE J1772 connector body architecture  146  is that of a rigid body design, which incorporates mechanical features promoting cross-linking adhesion and/or enabling mechanical bonding and mechanical locking features with the premold  120  and the overmold  122 . These mechanical features may include flow-through channels, pierced holes, raised joggles or ridgelines. 
         [0029]    The connector body contains five 353½ hard brass contacts  104 ,  106 ,  108 ,  110 ,  112 , as described above, which can be silver or gold plated. The two Size 8 power contacts  104 ,  112  incorporate elliptically wound high amperage and low insertion force internal helical springs  148  to enable higher amperage with reduced opportunities for heating due to micro-arcing, as well as offering additional opportunities of success for reverse compatibility to vehicle inlets (IAW SAE J 1772) manufactured by other manufacturers. These internal helical springs  148  also aid in accommodating the natural tendencies of process shift over time. The springs  148  can be configured as a plurality of toroidal springs, as shown, e.g., in U.S. Pat. No. 4,810,213 to Chabot, whose disclosure is hereby incorporated by reference in its entirety into the present disclosure. 
         [0030]    The insert molded SAE J1772 connector body  146  also incorporates a flame retardant (FR) UL listed closed cell gasket  150  on the mating face to aid in the prevention of attack on the contacts from corrosive gases such as carbon dioxide, sulfur dioxide, and hydrogen sulfide. 
         [0031]    The connector body  146  is then assembled to an FFSO UL listed cable  114 , shown by itself in  FIG. 10 , by means of a soldering operation to accommodate the pin-out diagram as specified in SAE J1772, as shown in  FIG. 11 . The soldered contacts of the insert molded SAE J1772 allow for improved cable retention of the overall assembly as well as reduced opportunities for micro-arcing and stray strands, which could lead to risks of shorts and ground faults, reducing the life cycle of the product. Additionally, soldered contacts provide for an additional level of defense to deter the wicking and capillary effect of moisture absorption at the exposed contacts. Water and moisture absorption, or wicking, accelerates copper corrosion and reduces the product life cycle, which may result in higher amperage draw from the branch circuit resulting in excessive heat and customer dissatisfaction. 
         [0032]    An environmentally sealed micro-switch sub assembly  152  is soldered to an FR-4 PC UL listed PC board  154 , which incorporates one 150 Ohm ½ watt resistor  156  and one 300 Ohm ½ watt resistor  158 , to implement the circuitry  140  described above as a micro-switch assembly. A grommet, shown in  FIGS. 13A and 13B  as  164 , is then added to the micro-switch sub-assembly  140  and assembled into position, as shown in  FIG. 14 . The grommet is manufactured from a polymeric molding compound which is UL94 V-1 flame rating with an environmental (f1) ultra-violet rating and a relative thermal index (RTI) equal to or exceeding 90 for electrical and physical impact and strength characteristics, as specified by UL 2251. The assembly  152  and board  154  are attached to the connector body  146 , as shown in  FIG. 15 , by means of soldering the two flying leads (proximity and ground)  160 ,  162  to the proximity and ground pin contacts  106 ,  108 , enabling the DC pulse signals required by the SAE J1772 Standard. This PC board  154  also provides for the silver path provisions to incorporate LED signals for charge and flashlight requirements that may be activated or required by the EV SE. 
         [0033]    When the soldering operation has been completed, the connector body  146 , PC board assembly  154 , and cable  114  are environmentally and dielectrically potted, as shown in  FIGS. 16A and 16B , with a two-part potting compound  166  that has a UL94 HB or V-0 flame rating and a relative thermal index (RTI) equal to or greater than 90 for electrical, physical impact and strength characteristics, as specified by UL 2251, to form the potting  116 . This potting compound  166  will then be cured either by overnight stall, or with a heat assist manufacturing aid. The FFSO electric vehicle cable jacket, insulated conductors and soldered connections will be encapsulated with this two part potting compound. 
         [0034]    This potting compound  166  provides for the first level of defense to deter the wicking and capillary effect of moisture absorption at the exposed contacts. Copper stranding can, over time, enable a capillary effect in which moisture wicks from the exposed contact area into the copper stranding which accelerates copper corrosion and reduces the product life cycle, which may result in higher amperage draw from the branch circuit resulting in excessive heat and customer dissatisfaction. The potting compound  166  also offers dielectric properties, further insulating the assembly from potential in air arcing between the power contacts and ground. This potting compound  166  is the foundation in which the additional polymeric materials will use for additional structure and support within the design. 
         [0035]    After the two-part environmentally and dielectrically potted compound  166  has cured and outgassed completely to form the potting  116 , a pre-mold  120  will then be molded over the sub-assembly that includes the connector body  146 , the FFSO electric vehicle cable  114 , and the potted contact, as shown in  FIG. 17 . The pre-mold is a high impact Polyamide (PA6 or PA66) based material with a UL94 V-0 flame rating and a relative thermal index (RTI) equal to or greater than 100. Other specially engineered compounds, such as glass filled polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), thermoplastic elastomer (TPE), thermoplastic vucanizate (TPV), or high impact polypropylene (HIPP), can be used. The pre-mold  120  encapsulates the subassembly, providing for the ‘backbone’ of the architecture, as well as adding additional environmental and dielectric properties to the overall SAE J1772 molded connector assembly system. The pre-mold  120  includes holes  168  corresponding to the holes  142  of the finished product. 
         [0036]    The pre-mold architecture is that of a rigid body design, which incorporates mechanical features promoting either cross-linking adhesion and/or enabling mechanical bonding and mechanical locking features of an outer ‘over-mold skin’ layer. These mechanical features may include flow-through channels, raised joggles or ridgelines, or depressed valleys and flow-through T-channels. 
         [0037]    The over-mold or skin, shown in  FIG. 18  as  122 , is for user interface, impact energy absorption, abrasion resistance, fluid and gasoline resistance and overall ultra-violet (UV) protection of the overall SAE J1772 molded connector assembly system. The overmold material of the SAE J1772 Connector Assembly has a UL94 HB or V-1 flame rating and a relative thermal index (RTI) equal to or greater than 90 for electrical, physical impact and strength characteristics, as specified by UL 2251. Alternate thermoset materials, such as EPT, EPDM, and silicone or liquid silicone injection, may also be incorporated to accommodate the physical and performance requirements of the outer skin. 
         [0038]    Once the system is completely molded, a latch arm  130  manufactured from a polymeric material such as polycarbonate (PC) with a UL94 V-0 flame rating, an environmental (f1) ultra-violet rating and a relative thermal index (RTI) equal to or exceeding 100 for electrical and physical impact and strength characteristics, as specified by UL 2251, is attached. This latch arm is attached by means of a molded or stainless steel (300 Series) pin. The latch provides for the mechanical interlock to the SAE J1772 vehicle inlet as well as the mechanical lever activating the micro-switch sub-assembly prior to commencing charging as well as upon completion of charging. The steps of attaching the latch arm include inserting the latch spring  134  into the latch area  128 , as shown in  FIG. 19 ; inserting the latch arm  130  over the spring  134  into the latch area  128 , as shown in  FIG. 20 ; and inserting the latch pin  132 , as shown in  FIG. 21 . 
         [0039]    Additionally, the market currently only offers 30 AMP and 75 AMP listed assemblies, which are mostly governed by the cable and contact size. The technologies implemented in the preferred embodiment allow a higher current rated (higher amperage) cable assembly to future proof the design for any DC fast charge requirements. 
         [0040]    The preferred embodiment provides a ruggedized and robust SAE J1772 overmolded connector assembly incorporating dielectric and environmental potting compounds, with an integrated polymeric substrate and overmolded polymeric skin offering protection from extreme and harsh environmental conditions. The preferred embodiment combines an overmolded integrated polymeric (laminated) approach and an integrated PC board with micro-switch and provisions for LED lights for a charge indicator and a flashlight. The solution offers reduced life-cycle costs, improved product reliability, and a reduced risk of tampering and vandalism associated with mechanical locking features and hardware (such as Torx™ screws). This over-molded solution offers exceptional environmental protection from the extreme environmental elements which may include: water, ice, dust, ultra-violet rays, oils and automotive fluids. 
         [0041]    While a preferred embodiment has been set forth above, those skilled in the art who have reviewed the present disclosure will readily appreciate that other embodiments can be realized within the scope of the invention. For example, any suitable latching mechanism can be used, as can any suitable materials. Also, the connector can be adapted to any standard or proprietary layout. Therefore, the present invention should be construed as limited only by the appended claims.