Patent Abstract:
An apparatus for connection of a rapid charging system to an electric vehicle includes a connector plug that is attached to an electrical cable at one end that is, in turn, connected to a charging system at the remaining end of the cable. The connector plug is adapted to fit into a mating receptacle that is attached to the electric vehicle. A pair of cavities in the connector plug are adapted to receive any combination of modules that include switches, lights, or blank filler plugs. The connector plug is preferably molded from rubber. Various contacts are described having high current, or signal, or pilot functions and which mate with various length pins in the mating receptacle so as to sequence the order in which electrical conductivity is attained. Temperature sensing of the connector and shutdown subsequent to an over-temperature condition is described and allows for the use of smaller sized electrical connectors.

Full Description:
[0001]    This application claims the benefit of priority of Provisional Patent Application SN 60/221613 that was filed on Jul. 28, 2000. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention, in general relates to electrical connectors and, more particularly, to high current (200-600 amperes) connectors that are intended to rapidly charge the batteries of an electric vehicle (i.e., a vehicle that obtains at least some of its motive power from an electric motor).  
           [0004]    As electrically powered and hybrid types of electric and gasoline vehicles continue to grow in design and in popularity, so too does the need to better support these types of vehicles.  
           [0005]    Certain of these types of vehicles are driven on the street while others are used in specific areas, such as in airports for the towing of airplanes, baggage, or for other purposes, for example, as fork lifts.  
           [0006]    Another group of electrical vehicles that may benefit from rapid recharging is classified, generally, as “Neighborhood Electric Vehicles”. These vehicles, while street legal, are limited to speeds under 30 mph and are becoming increasingly popular for use in retirement communities.  
           [0007]    As used throughout this specification, the term “electric vehicle” is intended to include any type of an electrically powered vehicle.  
           [0008]    Regardless of where they are used, the need to rapidly recharge the batteries of an electric vehicle exists. As this technology continues to advance, new types of batteries and new types of charging systems are being designed. It is desirable, in general, to be able to charge an electric vehicle as rapidly as possible. Rapid charging minimizes downtime.  
           [0009]    Various standards for recharging electric vehicle batteries presently exist and new ones are likely to be developed. For example, according to SAE J1772 “Society of Automotive Engineers Specification”, a “level 3” charge method utilizes 400 amperes maximum charge current and allows a discharged battery to be charged to approximately 80% of its capacity in a short period of time. Clearly, a very large amount of current must be supplied to accomplish recharging within the allotted time frame. (The verbs “charge” and “recharge” or “charging” and “recharging” are used interchangeably herein.)  
           [0010]    By way of comparison, a “level 1” rate of charging involves only twelve amperes maximum charge current and requires from six to twelve hours to reach the same battery capacity.  
           [0011]    In order to accommodate high current flows, large connectors are used but these then result in high insertion and removal forces which make it difficult for users to connect the charging system plug to the electric vehicle or remove it therefrom.  
           [0012]    It has generally been accepted that a hazardous voltage is 48 volts or higher when conditions are dry and 30 volts or higher when conditions are wet.  
           [0013]    At airports, electric vehicles operate at from 48 to 150 volts DC. Accordingly, protection from electrical hazard is required for those who handle the electrical connectors that recharge these vehicles.  
           [0014]    Also, there are other functions and indications that are desirable on a connector (i.e., a plug) for connection to an electric vehicle but which are currently unavailable. For example, an on/off switch to control operation of the recharging system (i.e., the application of electrical power for recharging the electric vehicle&#39;s battery through the connector) is desirable.  
           [0015]    As electric vehicle recharging systems grow in sophistication, there may arise a desire to control any of a variety of other functions as well. The use of indicator lights may also be desirable at times and they may used to indicate any condition, such as proper connection of the plug to the mating receptacle, proper or improper rate of charging, power “on” or “off”, etc . . . .  
           [0016]    Accordingly, there exists today a need for an electric vehicle battery rapid charging connector that has a lower insertion and removal force, incorporates safeguards, and which provides for additional functionality.  
           [0017]    2. Description of Prior Art  
           [0018]    High current electrical connectors are, in general, known. While the structural arrangements of the above described devices, at first appearance, may have similarities with the present invention, they differ in material respects. These differences, which will be described in more detail hereinafter, are essential for the effective use of the invention and which admit of the advantages that are not available with the prior devices.  
         OBJECTS AND SUMMARY OF THE INVENTION  
         [0019]    It is an object of the present invention to provide an electric vehicle battery rapid charging connector that has a lower insertion force than similar capacity types of prior art electrical connectors.  
           [0020]    It is also an important object of the invention to provide an electric vehicle battery rapid charging connector that is versatile.  
           [0021]    Another object of the invention is to provide an electric vehicle battery rapid charging connector that is adapted to permit temperature sensing of the battery that is being charged or, alternately, of the connector itself, or both.  
           [0022]    Still another object of the invention is to provide an electric vehicle battery rapid charging connector that is adapted to supply a signal to a charging system whereby the charging system can respond to an over-temperature condition by shutting down or otherwise limiting its operation.  
           [0023]    Still yet another object of the invention is to provide an electric vehicle battery rapid charging connector that includes a cavity that is adapted to accept either one or a plurality of modules, the modules including any combination of indicator lights and/or switches or a blank cover that is adapted to block access to the cavity.  
           [0024]    Yet another important object of the invention is to provide an electric vehicle battery rapid charging connector that includes smaller sized contacts (i.e., socket and pin) than other similar capacity types of electrical connectors.  
           [0025]    Still yet another important object of the invention is to provide an electric vehicle battery rapid charging connector that embodies safeguards for use.  
           [0026]    Still yet one further object of the invention is to provide an electric vehicle battery rapid charging connector that is durable and rugged.  
           [0027]    Still yet one further important object of the invention is to provide an electric vehicle battery rapid charging connector that has a lower insertion force for inserting a plug into a mating receptacle than other types of similar capacity connectors.  
           [0028]    Briefly, an electric vehicle battery rapid charging connector that is constructed in accordance with the principles of the present invention has a rubber or plastic molded body that includes a predetermined size and shape. The connector includes two large DC power contacts and 1 large grounding contact and six smaller signal contacts. The smaller signal contacts may be used for functions such as battery or connector temperature sensing, voltage sensing, pilot, and other functions, as desired. Preferably, silver plated copper socket contacts that are crimped onto conductors that are contained in an electrical cable are used. The connector may include two cavities that can each accept either a module or a rubber blank. Each module may include any combination of on/off switches or indicator lights, as desired. When mating occurs (i.e. when the connector plug is inserted into a mating receptacle that is attached to the electric vehicle), connection of electrical ground is accomplished first, followed by the positive and negative high current contacts, followed by five of six control signals making contact, followed lastly by a pilot pin making contact which enables current flow to occur after all of the other connections are first ensured. Sequenced electrical connectivity is accomplished by controlling the length of the pins in the mating receptacle. Removal of the connector plug from the mating receptacle reverses the order of disconnection and ensures that current flow has ceased prior to disconnection of the power contacts. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0029]    [0029]FIG. 1 is view in perspective an electric vehicle battery rapid charging connector with a plurality of modules inserted therein. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]    Referring to FIG. 1 is shown, a plug half of an electric vehicle battery rapid charging connector, identified in general by the reference numeral  10  that includes a predetermined size and shape, the shape being generally as shown.  
         [0031]    A cable  12  which contains the necessary electrical conductors enters into t he back of the connector  10 .  
         [0032]    A body, identified in general by the reference numeral  14 , is rubber or plastic molded and includes a first and second cavity  16 ,  18  (shown in dashed lines) that are formed therein.  
         [0033]    A ground socket  20 , a positive charging socket  22 , and a negative charging socket  24  are included in a distal end of the connector  10  that is opposite the back and are large enough to carry the maximum required charging current for a predetermined period of time, as is described in greater detail hereinafter.  
         [0034]    Six smaller signal contact sockets  26 ,  28 ,  30 ,  32 ,  34 ,  36  are also provided in the distal end proximate the ground socket  20 , the positive and negative charging sockets  22 ,  24  which are used for temperature sensing, voltage sensing, pilot connection, and for other purposes, as desired.  
         [0035]    When the connector  10  is inserted into a mating receptacle  37  that is attached to an electric vehicle  37   a  (Only a small portion of a mounting bracket is shown, the mounting bracket being attached to and therefore part of the electric vehicle  37   a. ), the various electrical connections are made at different times as insertion progresses.  
         [0036]    This is accomplished by controlling the length of the pins (not shown) that are in the receptacle  37 . The longest pin is a ground pin and it makes electrical contact with the ground socket  20  before any other connection is made.  
         [0037]    The second longest set of pins are a positive pin and a negative pin that mate with the positive charging socket  22  and the negative charging socket  24 .  
         [0038]    Five signal pins are the third longest set of pins that are included in the receptacle  37  and they are shorter than the second longest set of pins. The five signal pins mate with five of the six smaller signal contact sockets  26 ,  28 ,  30 ,  32 ,  34  and are used for temperature or voltage sensing (of a battery or batteries in the electric vehicle) and to control other functions, as desired.  
         [0039]    A sixth signal pin is the shortest of all of the pins in the receptacle  37  and is therefore last to make electrical connection with the sixth signal contact socket  36  of the connector  10 . The sixth signal contact socket  36  is preferably used to complete a pilot connection.  
         [0040]    For example, the circuit may be completed through the receptacle  37  and back through one of the other signal pins through the corresponding signal contact socket ( 26 ,  28 ,  30 ,  32 , or  34 ) and back through the cable  12  to a charging system (not shown).  
         [0041]    When the pilot connection is complete, the charging system is then able to determine that the connector  10  has been fully inserted into the receptacle  37  and that the charging system may now, if desired, begin to apply rapid charging current through the positive and negative sockets  22 ,  24  and, if desired, to sense other parameters being monitored and, if desired, to control other functions, as is described in greater detail hereinafter.  
         [0042]    Any or all of the sockets  20 ,  22 ,  24 ,  26 ,  28 ,  30 ,  32 ,  34 ,  36  are preferably silver plated copper socket contacts that are crimped onto conductors that are contained in the electrical cable  12 .  
         [0043]    To minimize the amount of insertion force that is required to insert the connector  10  into the receptacle  37 , any of the sockets  20 ,  22 ,  24 ,  26 ,  28 ,  30 ,  32 ,  34 ,  36  preferably may include a split tine type of a socket as is described in Provisional Patent Application, SN 60/221,612 filed on Jul. 28, 2000 by the same inventor, and which is included by reference herein.  
         [0044]    While according to the above description, the sixth signal pin is the shortest and mates with the sixth signal contact socket  36 , it is of course possible to have the shortest sixth signal pin mate disposed elsewhere in the receptacle  37  so that it mates with any of the six smaller signal contact sockets  26 ,  28 ,  30 ,  32 ,  34 ,  36 , as may be desired.  
         [0045]    It is also possible to vary the length of any of the pins so as to modify the sequence that electrical connections are made when the connector  10  is inserted in the receptacle  37 .  
         [0046]    It is also possible to change the location of the pins and sockets so that sockets are disposed in a modified receptacle and pins are disposed in a modified connector.  
         [0047]    When the connector  10  is pulled from the receptacle  37 , electrical connection is broken in reverse order, namely the last socket(s) to make connection during insertion is the first to lose it during removal.  
         [0048]    A first module  38  is shown disposed above the first cavity  16  for purposes of clarity and also in the first cavity  16  where it belongs so that its top is approximately flush with the top surface of the body  14  at that area. The first module  38  contains an “on” switch  38   a  and an “off” switch  38   b  that can be depressed to turn “on” or “off” any desired function.  
         [0049]    For example, the “on” switch  38   a  of the first module  38  can be used to turn “on” charging power when either of a pair of indicator lights  40 ,  42  of a second module  44  indicate that all conditions for doing so have been satisfied. This can be done in lieu of, or in conjunction with the pilot connection, depending upon the degree of safeguards that are desired.  
         [0050]    The second module  44 , as shown, is disposed above the body  14  (for clarity) and also in the second cavity  18  where it is normally disposed.  
         [0051]    A third module  46  is a rubber blank and it can be inserted to fill (i.e., block) either the first cavity  16 , or the second cavity  18 , or both, as desired when a pair of the third modules  46  are used.  
         [0052]    The modules  38 ,  44 ,  46  are secured in place in the cavities  16 ,  18  as desired. One possible way is by screws  47  passing through a pair of openings  48  in each of the modules  38 ,  44 ,  46  and making contact with the body  14  proximate the cavities  16 ,  18  sufficient to retain the modules  38 ,  44 ,  46  therein.  
         [0053]    Sensing of the temperature and/or voltage of the battery can be accomplished by the charging system (via the six smaller signal contact sockets  26 ,  28 ,  30 ,  32 ,  34 ,  36 ) to verify that a proper recharging cycle is taking place. If an anomaly is detected, the charging system can shut down and abort the recharging cycle. If desired, one of the indicator lights  40 ,  42  can then be illuminated to indicate that this (i.e., a fault condition) has occurred.  
         [0054]    Prior art connector design (not shown) requires that the pins and sockets must be large enough to carry the intended current load and to do so indefinitely. This is because in other prior art applications the duty cycle may be expected to vary from zero anywhere up to 100% and therefore, the maximum current may have to be delivered constantly. Therefore, the pins and sockets must be able to handle this load indefinitely and so they are made large enough to do so. Those skilled in prior art connector design routinely design the pins and sockets so that they can indefinitely handle the greatest current that they will normally experience by using larger types of connector pins and sockets. Larger connector mating (i.e., pins and sockets) is disadvantageous because it requires greater insertion (and withdrawal) force for mating and un-mating to occur. It also results in physically larger and heavier connectors.  
         [0055]    However, rapid battery charging of electric vehicle batteries does not maintain maximum current flow throughout the entire charging (recharging) cycle. Rather, the rate of charging (i.e., current flow) decreases as the battery or batteries become more fully charged. Accordingly, the pins and sockets that carry the charging load (and ground) of the instant invention  20 ,  22 ,  24  may be made smaller than what would be required to sustain a continuous maximum load, provided that other safety controls to limit the current flow either over time or upon the occurrence and detection of other abnormal conditions are also provided.  
         [0056]    During a normal charging cycle, a very high rate of current flow will initially occur and this rate will decrease over time. The battery temperature and voltage sensing capabilities discussed above can be used by the charging system to detect improper operation (in the electric vehicle  37   a ) which, if detected, could then result in a cessation of charging current flow through the connector  10 .  
         [0057]    An increase in the temperature of the connector  10  itself is another condition that can be caused by several factors, including an excessively high rate of charge that exceeds the current carrying capacity of the connector  10 , a protracted rate of a maximally permissible current flow that exceeds the maximum permissible time, or a failure in any of the positive, negative, or ground contact sockets  20 ,  22 ,  24 . Any of these conditions will result in an increase (i.e., a rise) in the temperature of the connector  10 .  
         [0058]    A failure, for example, in the contact sockets  20 ,  22 ,  24  could be of the form of an increase in the electrical resistance between the socket  20 ,  22 ,  24  and its mating pin, such as from dirt or insufficient contact pressure. An increase in electrical resistance would cause an increase in power consumption in the connector  10  to occur, which would then cause a rise in temperature to occur.  
         [0059]    If this were to continue undetected the potential for damage is great. The battery or batteries in the electric vehicle  37   a  may be damaged, or the electric vehicle  37   a  might suffer damage resulting from great heat. Similarly, the connector  10  itself could become damaged.  
         [0060]    Any of the six smaller signal contact sockets  26 ,  28 ,  30 ,  32 ,  34 ,  36  can, if desired, be connected to a resistance temperature detector  49  (hereinafter as “the RTO 49”) (i.e., a method or device for sensing or otherwise determining the temperature of the connector  10 , such as a thermocouple). The resistance of the RTO 49 changes with temperature and so it is used to provide an electrical signal that is proportionate to the temperature of the connector  10  and this signal is monitored by the charging system.  
         [0061]    If a maximum threshold temperature is exceeded, it can be assumed that either a failure has occurred or that some other improper and potentially unsafe condition has arisen.  
         [0062]    Accordingly, the charging system would then either reduce or interrupt the charging current once the maximum permissible operating temperature of the connector  10  was exceeded.  
         [0063]    Alternatively, this functionality may also be achieved by the use of a temperature sensing switch attached to the connector  10  which would interrupt the pilot circuit when a predetermined temperature is exceeded.  
         [0064]    This provides a method for determining and for monitoring the temperature of the connector  10 . This, in turn, provides a more reliable mechanism whereby smaller contacts may be used in high current applications that would otherwise be impossible because current flow through the smaller contacts (i.e., sockets) can be stopped (or lessened) if any type of a fault condition causes a dangerous temperature rise to occur in the connector  10 .  
         [0065]    A signal indicating the temperature of the connector  10  is supplied to the charging system which then controls current flow through the connector  10 . Other signals indicating the temperature and voltage of the electric vehicles battery or batteries (or any other desired parameter) are also supplied to the charging system. All component parts, therefore, cooperate together so as to provide a system for ensuring the controlled and rapid charging of the electric vehicle&#39;s  37   a  battery or batteries.  
         [0066]    As rapid charging systems continue to develop, they will deliver very large amounts of current (i.e., power) in increasingly shorter periods of time. The need to monitor system parameters to prevent damage from occurring is therefore also increasing. The connector  10  provides the versatility and improved functionality to permit such monitoring to occur.  
         [0067]    To facilitate use, three raised ridges  50  are provided on the outside edges and intermediate the two cavities  16 ,  18  of the connector  10  that extend longitudinally the length of the cavities  16 ,  18 . The ridges  50  help ensure that the fingers of a user can readily find the desired switches and they also protect the modules from damage.  
         [0068]    The invention has been shown, described, and illustrated in substantial detail with reference to the presently preferred embodiment. It will be understood by those skilled in this art that other and further changes and modifications may be made without departing from the spirit and scope of the invention which is defined by the claims appended hereto.

Technology Classification (CPC): 8