Patent Publication Number: US-2020282851-A1

Title: Liquid cooled charging cable and connector

Description:
BACKGROUND 
     Technical Field 
     The present invention relates to electric vehicles; and more particularly to a liquid-cooled charging cable and charger for charging of electric vehicles. 
     Description of Related Art 
     The advancement of electric vehicles has created an increased need for charging equipment that delivers electric power. Some such applications (e.g., certain fast-charging vehicle chargers) are designed to work with continuous currents of 100 Amps or more. With the advancement of larger electric vehicles, such as semi-tractor electric vehicles, charging duties have increased. Resultantly, charging cables may be required to service charging at 2,000 Amps or more. Higher current flow in a charging cable results in the generation of more heat, which must be removed to prevent overheating and damage to the charging cable. As a result, the conductors of the charging cables have traditionally been sized larger to match higher current draws, resulting in greater bulk, cost, and difficulty in handling. 
     SUMMARY 
     Various non-limiting aspects of the present disclosure will now be provided to illustrate features of the disclosed apparatus and methods. 
     In one embodiment, a charging system for an electric vehicle is disclosed. The charging system can include a power supply, a charging cable, and a connector. The charging cable can have a first end and a second end, the first end attached to the power supply. The charging cable can include a jacket along a length of the charging cable; a charging conductor within the jacket; a cooling conduit within the jacket; and a coolant return path within the jacket, but not within a conduit, that at least partially surrounds the charging conductor. The connector can be attached to the second end of the charging cable. The connector can include a chamber for communicating with the coolant conduit, wherein the charging conductor is exposed within the chamber. 
     In one embodiment, a charging cable for electric car is disclosed. The charging cable can include a conductor having an outer surface; a conduit configured to transport coolant through the charging cable; a jacket encasing the conductor and the conduit; a coolant return path, the coolant return path being defined by the free space within the jacket between the conductor and the conduit; a cable connector configured to connect the charging cable to an electric car; and a coolant return disposed within the cable connector and connected to the conduit, the coolant return having an opening to the coolant return path such that the conduit, coolant return path, and the coolant return are in fluid communication. In various embodiments, the outer surface of the conductor is at least partially exposed in the coolant return path and coolant flowing through the coolant return path contacts at least a part of the outer surface of the conductor. 
     In one embodiment, a connector for a charging cable for an electric vehicle is disclosed. The charging cable can include a conductor; a charging connector connected to the conductor, the charging connector configured to mate with a charging port; a chamber surrounding at least a part of the charging connector, the chamber having a first opening and a second opening; a conduit configured to transport a fluid, the conduit connected to the first opening such that the chamber and the conduit are in fluid communication; and a structure encasing the chamber, the conduit, the conductor and at least a part of the charging connector, the structure forming a pathway that is defined by the free space between the chamber, the conduit, the conductor, and at least a part of the charging connector, the pathway being connected to the second opening such that the chamber, the conduit, and the pathway are in fluid communication. In various embodiments, fluid flowing within the chamber can contact at least a part of the charging connector. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  illustrates the basic components of a battery powered electric vehicle. 
         FIG. 2  illustrates the basic components of a charging system according to a described embodiment. 
         FIG. 3  is a cross-sectional diagrammatic view of a charging cable according to a described embodiment. 
         FIG. 4  is a cross-sectional diagrammatic view of a connector according to a described embodiment. 
         FIG. 5  is a diagrammatic perspective view of a charging cable and connector according to a described embodiment. 
         FIG. 6  is a first diagrammatic perspective cut-away view of a charging cable and connector according to a described embodiment. 
         FIG. 7  is a second diagrammatic perspective cut-away view of a charging cable and connector according to a described embodiment. 
         FIG. 8  is an end view of a connector according to a described embodiment. 
         FIG. 9  is a diagrammatic perspective view of a charging cable and connector in a near mating position with a charging port according to a described embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     The present disclosure describes examples of systems and techniques for cooling charging cables. A charging cable is a cable that can be used to transport or deliver electric power from one system to another. For example, a charging cable can be used to deliver electric power from a charging station to an electric vehicle such as a car or semi-truck. When the charging system delivers electric power at a high current (e.g. 100 Amps or more), the current flow within the charging cable can generate high amounts of heat. In some situations, this heat can cause several issues. For example, the heat can damage components of the charging system or cable and can make handling the heated cable very difficult or dangerous for a user. In charging systems that deliver power at even higher currents (e.g. 1000 Amps or more), removing the heat from the charging cables can be vital to the safety of the operators and to the lifespan of the components involved in the charging system. 
     To remove heat from the charging cable, a cooling system can be implemented into the charging process. For example, a charging cable for an electric vehicle can be cooled by a liquid cooled system. Using liquid cooling to remove heat from a charging cable can provide several advantages. For example, using liquid cooling can allow for a higher current to be fed through the charging cable, as the effects of the heat are removed or greatly reduced. Additionally, using liquid cooling can allow for a more convenient cable design. With the effects of the heat being removed or greatly reduced, bulky and large cables are no longer needed to protect the equipment and user from the generated heat. Thus, the charging cable can be a lighter cable, thinner cable, and/or a more flexible cable. 
     One embodiment is an electric vehicle charging cable that includes a non-conductive liquid heat transfer medium. The charging cable may include a cooling conduit for transferring the coolant or liquid heat transfer media from a cooling system near a charging base to a connector which interfaces with a charging port on the electric vehicle. In this embodiment the connector includes an internal chamber adjacent the terminal ends of a pair of charging conductors which carry the electric current through the charging cable. In use, the non-conductive liquid heat transfer media exits the cooling conduit near the internal chamber and then contacts one or both charging conductors to remove heat from those terminal ends of the conductors within the chamber. The size and the dimensions of the internal chamber are designed to have a fairly small hydrodynamic diameter such that a relatively rapid flow of the liquid heat transfer media will interact with the charging conductors. 
     In one embodiment, the charging cable comprises an outer jacket or shell that is impermeable to liquid and acts to contain the liquid heat transfer media as it exits the internal chamber and flows back towards the cooling system and charging base. As the media flows along the internal spaces within the charging cable and jacket, the media can remove additional heat from the conductors that traverse the charging cable from the base to the connectors. In this embodiment, the media does not flow within a conduit as it returns to the charging base, but instead flows along all the internal spaces within the outer jacket of the charging cable. 
       FIG. 1  illustrates the basic components of a battery powered electric vehicle (e.g. electric vehicle)  100 . The electric vehicle  100  includes at least one drive motor (e.g. traction motor)  102 A,  102 B and/or  102 C, at least one gear box  104 A,  104 B, and/or  104 C coupled to a corresponding drive motor  102 A,  102 B, and/or  102 C, a battery  106  and electronics  108 . Generally, the battery  106  provides electricity to the electronics  108  of the electric vehicle  100  and to the drive motors  102 A,  102 B and/or  102 C to propel the electric vehicle  100  using the drive motors  102 A,  102 B and/or  102 C. The electric vehicle can include a charging port  118 , which can be used to receive energy to charge/recharge the battery  106 . In some embodiments, the electric vehicle  100  includes a number of other components that are not described herein. While the construct of the electric vehicle  100  of  FIG. 1  is shown to have ten wheels, differing electric vehicles may have fewer or more than ten wheels. Further, differing types of electric vehicles  100  may incorporate the concepts described herein. 
       FIG. 2  illustrates a schematic of the basic components of a charging system according to a described embodiment. The charging system  200  includes a power supply  202 , a coolant system  204 , a charging cable  206  and a connector  208 . The charging cable  206  has a first end and a second end, the first end attached to the power supply  202 . In some embodiments, the charging cable  206  can include a j acket, charging conductors within the jacket, a pair of signaling conductors within the jacket, a cooling conduit within the jacket, and a coolant return path within the jacket. In some embodiments, the coolant return path within the jack can at least partially surround the charging conductors, the pair of signaling conductors, and the cooling conduit. The connector  208  attaches to the second end of the charging cable  206 . In some embodiments, the connector  208  can include a support structure, charging connectors within the support structure that electrically couple to the charging conductors, a pair of signaling connectors within the support structure that electrically couple to the signaling conductors, and a coolant return within the support structure that couples between the cooling conduit and the coolant return path. 
     The coolant system  204  provides coolant to the charging cable  206  and receives heated coolant from the charging cable  206 . The coolant system  204  disperses heat within the received coolant by dispersing heat to the ambient via a radiator, a refrigerator system or process, or a combination of both. In other embodiments, the coolant system  204  can disperse the heat of the coolant through other means. The coolant can be any coolant that resists electrical shortages while still providing beneficial heat transfer and thermal properties. For example, the coolant can be a dielectric oil, which is non-conductive and can resist electrical shorts while providing beneficial thermal properties. In various embodiments, a pump can be connected with the coolant system  204 . The pump can be directly connected to the charging cable  206  (e.g. with no intervening parts), or it can be indirectly connected to the charging cable  206  (e.g. with at least one part between the charging cable  206  and the pump). The pump can be used to pump coolant through the system. In some embodiments, the charging system  200  provides in excess of 2000 Amps of charge at 1500 Volts, for example, to support both as long-haul applications where DC fast charging is required (1-2 MW) as well as overnight DC charging (100 kW). 
       FIG. 3  is a cross-sectional diagrammatic view of a charging cable according to a described embodiment. The charging cable  206  includes a jacket  300 , charging conductors  302  and  304  within the jacket, a pair of signaling conductors  306  and  308  within the jacket, a cooling conduit  310  within the jacket  300 , and a coolant return path  312  within the jacket  300 . In various embodiments, the jacket  300  can be made from a material that is impermeable to a coolant and can resist corrosion from a coolant. In some embodiments, the jacket  300  can be made from rubber, a rubber substitute, plastic, a separate material, or a combination of materials. In some embodiments, the coolant return path  312  is not a separate conduit within the jacket  300 , but is instead the free space within the jacket  300 . The free space in the jacket  300  can be defined as the space between the charging conductors  302 ,  304 , the signaling conductors,  306 ,  308 , the cooling conduit  310 , and within the jacket  300 . The coolant return path  312  can at least partially surround the charging conductors  302  and  304 , the pair of signaling conductors  306  and  308 , and the cooling conduit  310 . In some embodiments, coolant flowing within the coolant return path  312  can freely flow within the jacket  300 . 
     In various embodiments, the charging conductors  302 ,  304 , the signaling conductors  306 ,  308 , and the cooling conduit  310  are spaced apart from each other within the jacket  300 . Spacing apart these components within the jacket  300  creates free space that between these components within the jacket  300 . In some embodiments, coolant originates from the cooling system  204  and flows through the cooling conduit  310 . This coolant can flow out of the cooling conduit  310  through a coolant return and flow into the coolant return path  312 . The coolant flowing through the coolant return path  312  can return to the coolant system  204  where the coolant can disperse its captured heat and be returned back through the coolant conduit  310 . In various embodiments, a pump is used to pump the coolant through the cooling conduit  310 , the coolant return path  312 , and the coolant system  204 . In some embodiments, the charging conductors  302 ,  304  and the signaling conductors,  306 ,  308  do not have a thermal barrier so the coolant within the coolant return path  312  can directly contact the charging conductors  302 ,  304  and the signaling conductors,  306 ,  308 . In some embodiments, the coolant can contact the outer surface of the charging conductors  302 ,  304  and the signaling conductors  306 ,  308 . 
       FIG. 4  is a cross-sectional diagrammatic view of a connector according to a described embodiment. The connector  208  attaches to the second end of the charging cable  206  and includes a support structure  400 , charging connectors  402  and  404  within the support structure  400  that electrically couple to the charging conductors  302  and  304 , and a pair of signaling connectors  406  and  408  within the support structure  400  that electrically couple to the signaling conductors  306  and  308 . In some embodiments, the connector  208  can include a coolant return (as shown in  FIGS. 6 and 7 ) within the support structure  400  that couples between the cooling conduit  310  and the coolant return path  312 . The connector  208  can mate with a charging port  118  of an electric vehicle. For example, the substantially triangular cross section of the connector can be used to mate with a similarly shaped female charging port  118  on the electric vehicle  100 . 
     Referring to both  FIGS. 3 and 4 , the charging conductors  302  and  304  and the charging connectors  402  and  404  are constructed of a conductive metal with insulative surroundings. The conductive material may be copper, aluminum, an alloy, or another metal. The charging conductors  302  and  304  as well as the charging connectors  402  and  404  have sufficient sizing to carry 2000 amps of direct current or more. Because of the coolant flowing through the charging cable  200 , the charging conductors  302 ,  304  and the charging connectors  402 ,  404  are actively cooled. This active cooling leads to the connector  208  to not overheat, which allows for the support structure  400  to maintain a safe handling temperature. As a result, the connector  208  may be handled easily without injury to the handler. 
       FIG. 5  is a diagrammatic perspective view of a charging cable and connector according to a described embodiment. Shown are the charging cable  206  and the connector  208 , including the support structure  400 , the charging connectors  402  and  404 , and signaling connectors  406  and  408 . 
       FIG. 6  is a first diagrammatic perspective cut-away view of a charging cable and connector according to a described embodiment. Identified in  FIG. 6  is the coolant return  602  that receives coolant from the cooling conduit  310 . The coolant return  602  can connect with the cooling conduit  310  and be in fluid communication with cooling conduit  310  (e.g. the fluid can flow from the cooling conduit  310  into the coolant return  602 ). The coolant return  602  circulates the coolant about the charging connectors  402  and  404  and supports the return of the coolant via the coolant return path  312  of the cable  206 . In some embodiments, the coolant return  602  can form an open ended chamber that partially surrounds charging connectors  402 ,  404 . In various embodiments, the coolant return  602  forms a chamber that partially surrounds the charging connectors  402 ,  404  and the charging conductors  302 ,  304 . In other embodiments, the coolant return  602  forms a chamber that partially surrounds the charging conductors  302 ,  304 . The chamber can have a front wall, a top wall, a back wall, a bottom wall, and sidewalls. The front wall can prevent the coolant from escaping out of the front end the connector  208 . The walls of the chamber can direct or route the coolant to flow over and around the charging conductors  302 ,  304  or the charging connectors  402 ,  404 . In some embodiments, the size and shape of the chamber can determine the flow characteristics of coolant flowing into the chamber. For example, a chamber with a small hydrodynamic diameter (e.g. a diameter that is about half or smaller than half of the diameter of the jacket  300  or connector  208 ) can have a faster flow rate of coolant than chamber with a large hydrodynamic diameter (e.g. a diameter that is larger than about half the diameter of the jacket  300  or connector  208 ). The hydrodynamic diameter of the chamber can be a variety of sizes. For example, the chamber can have a hydrodynamic diameter that is about one-third, one-fourth, one-sixth, one-eighth, or one-tenth the diameter of the jacket  300 . In other embodiments, the chamber can have a hydrodynamic diameter that is about one-third, one-fourth, one-sixth, one-eighth, or one-tenth the diameter of the connector  208 . The chamber can have an open end near the back or sides of the chamber. In various embodiments, the open end can be located at other portions of the coolant return  602  and along multiple locations of the coolant return  602 . This open end can connect with the coolant return path  312  and form a pathway that opens into the coolant return path  312  so the coolant return  602  can be in fluid communication with the coolant return path  312 . In some embodiments, the chamber of the coolant return can have a first opening that is in communication with the coolant conduit  310  and a second opening that is in communication with the coolant return path. In various embodiments, coolant flowing into the coolant return  612  from the coolant conduit  310  can flow over the charging conductors  302 ,  304  or charging connectors  402 ,  404  and exit the coolant return  612  into the coolant return path  312 . In some embodiments, the coolant return  602  is sized and shaped to prevent coolant from flowing over the signaling connectors  406 ,  408 . In other embodiments, the coolant return is sized and shaped so as to allow coolant to flow over at least a part of the signaling connectors  406 ,  408 . In some embodiments, the pathway formed in part by the open end of the coolant return  602  can also include the free space between the chamber, the cooling conduit  310 , the charging connectors  402 ,  404 , the signaling connectors  406 ,  408 , the charging conductors  302 ,  304 , and the signaling conductors  306 ,  308  within the support structure  400 . In some embodiments, the coolant return  602  can dump coolant directly over charging conductors  302 ,  304  and the charging connectors  402 ,  404 . The charging conductors  302 ,  304  and the charging connectors  402 ,  404  can be exposed so there is no thermal barrier between the coolant, the charging conductors  302 ,  304 , and the charging connectors  402 ,  404 . 
       FIG. 7  is a second diagrammatic perspective cut-away view of a charging cable and connector according to a described embodiment. The coolant return  602  is showing its relationship to the charging connectors  402  and  404  and the charging conductors  302  and  304 . As shown in  FIG. 7 , the coolant return  602  can partially be positioned in between the charging connectors  402  and  404 . The coolant return  602  can also have sidewalls that are positioned outside of the charging connectors  402  and  404 . The coolant return  602  can have an open end that opens to coolant return path  312  of the charging cable. With the structure of the described embodiment, the charging connectors  402  and  404  may have a 50 degree C. rise in temperature while the connector  208  only has a 5 degree C. external rise in temperature and the charging cable  206  only has a 10 degree C. external rise in temperature. The relatively low temperature rise of the connector  208  and the charging cable  206  allows for handling when still heated after charging a vehicle. Using advanced plastics and/or active cooling, which is achieved by pumping coolant through the cable  206 , connector  208 , and a cooling system  204 , allows for higher internal socket temperatures. 
     The connector  208  is constructed such that the signaling connectors  406  and  408  disengage from a charging port  118  prior to the charging connectors  402  and  404  disengaging from the charging port  118 . This structure can be achieved by utilizing signaling connectors  406 ,  408  that are longer than the charging connectors  402 ,  404 . In some embodiments, the signaling connectors  406 ,  408  may extend further out from the connector  208  than the charging connectors  402 ,  404 . In various embodiments, the design of the charging port  118  will permit the signaling connectors  406 ,  408  to disengage from the charging port  118  prior to the charging connectors  402 ,  404  from disengaging. With this structure, the charging system  200  may cut off power based upon detected loss of signaling prior to disengagement of the charging connectors  402  and  404  from the charging port  118 . A CPU can be connected to the charging system  200 . The CPU can determine when a loss of signaling is present and send a command to cut off the power. By having only two signaling connectors  406  and  408  (as well as only two signal conductors  306  and  308  of the charging cable  206 ), the signaling connectors  406  and  408  occupy less of the cross sectional area of the connector  208  and charging cable  206 . 
       FIG. 8  is an end view of a connector  208  according to a described embodiment. The end view  800  of  FIG. 8  is similar to the view of  FIG. 3  and shows the support structure  400 , the charging connectors  402  and  404  within the support structure  400 , and a pair of signaling connectors  406  and  408  within the support structure  400 . 
       FIG. 9  is a diagrammatic perspective view of a charging cable and connector in a near mating position with a charging port according to a described embodiment. The charging port  118  has a structure complementary to the connector  208  to receive the components thereof (as shown in  FIG. 8 ). Thus, the charging port  118  has a form factor complimentary to the form factor of the connector  208 . 
     An example method of using the charging will now be described. A user can connect a charging system  200  to an electric vehicle  100 . The user can connect the charging system  200  to the electric vehicle  100  by connecting the connector  208  of the charging cable  206  to the electric vehicle&#39;s  100  charging port  118 . When the connector  208  is connected to the charging port  118 , the signaling connectors  406 ,  408  electrically connect with the complimentary signaling receivers on the charging port  118 . Additionally, the charging connectors  402 ,  404  electrically connect with the complimentary charging receivers on the charging port  118 . Once the connector  208  is connected to the charging port  118 , data can be sent from the electric vehicle to the charging system through the signaling connectors  406 ,  408  and signaling conductors  306 ,  308 . Additionally, electric power can be sent from the power supply  202  of the charging system  200  to the electric vehicle  100  by sending the power through the charging conductors  302 ,  304  and the charging connectors  402 ,  404 . As the power supply  202  charges the battery  106  of the electric vehicle  100 , coolant from the coolant system  204  can be pumped through the charging cable  206  and connector  208 . The coolant can enter into the charging cable  206  through the coolant conduit  310 . The coolant conduit  310  can transport the coolant from one end of the charging cable  206  to the connector  208 . The coolant conduit  310  can be connected to and in fluid communication with the coolant return  602 . As coolant enters into the coolant return  602 , the coolant is routed over the charging connectors  402 ,  404  by the coolant return  602 . After the coolant is routed over the charging connectors  402 ,  404 , the coolant exits the coolant return  602  and flows into the coolant return path  312 . The coolant can fill the free space within the jacket  300  created by the spacing between the charging conductors  302 ,  304 , the signaling conductors  306 ,  308 , and the coolant conduit  310 . The coolant within the coolant return path  312  can travel back to coolant system  204 , where heated is removed from the coolant. The heat can be removed from the coolant through a radiator, a refrigeration process, or other heat removal process. Once heat is removed from the coolant, the coolant can be pumped back through the coolant conduit  310 . The coolant can be cycled through the coolant system  204 , charging cable  206 , and connector  208  repeatedly and throughout the duration of the charging process. Once the user disconnects the connector  208  from the charging port  118 , the charging system  200  can detect a loss of signal from the signaling conductors  306 ,  308  and the signaling connectors  406 ,  408 . 
     In the foregoing specification, the disclosure has been described with reference to specific embodiments. However, as one skilled in the art will appreciate, various embodiments disclosed herein can be modified or otherwise implemented in various other ways without departing from the spirit and scope of the disclosure. Accordingly, this description is to be considered as illustrative and is for the purpose of teaching those skilled in the art the manner of making and using various embodiments of the disclosed system, method, and computer program product. It is to be understood that the forms of disclosure herein shown and described are to be taken as representative embodiments. Equivalent elements, materials, processes or steps may be substituted for those representatively illustrated and described herein. Moreover, certain features of the disclosure may be utilized independently of the use of other features, all as would be apparent toone skilled in the art after having the benefit of this description of the disclosure. 
     Routines, methods, steps, operations, or portions thereof described herein may be implemented through electronics, e.g., one or more processors, using software and firmware instructions. A “processor” includes any hardware system, hardware mechanism or hardware component that processes data, signals or other information. A processor can include a system with a central processing unit, multiple processing units, dedicated circuitry for achieving functionality, or other systems. Some embodiments may be implemented by using software programming or code in one or more digital computers or processors, by using application specific integrated circuits (ASICs), programmable logic devices, field programmable gate arrays (FPGAs), optical, chemical, biological, quantum or nano-engineered systems, components and mechanisms. Based on the disclosure and teachings representatively provided herein, a person skilled in the art will appreciate other ways or methods to implement the invention. 
     As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any contextual variants thereof, are intended to cover a non-exclusive inclusion. For example, a process, product, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements, but may include other elements not expressly listed or inherent to such process, product, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition “A or B” is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B is true (or present). 
     Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”, “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount. As another example, in certain embodiments, the terms “generally parallel” and “substantially parallel” refer to a value, amount, or characteristic that departs from exactly parallel by less than or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree, or 0.1 degree. 
     Although the steps, operations, or computations may be presented in a specific order, this order may be changed in different embodiments. In some embodiments, to the extent multiple steps are shown as sequential in this specification, some combination of such steps in alternative embodiments may be performed at the same time. The sequence of operations described herein can be interrupted, suspended, reversed, or otherwise controlled by another process. 
     It will also be appreciated that one or more of the elements depicted m the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application. Additionally, any signal arrows in the drawings/figures should be considered only as exemplary, and not limiting, unless otherwise specifically noted.