Patent Publication Number: US-2023135040-A1

Title: Systems and methods for efficient dc fast charging

Description:
INTRODUCTION 
     The present disclosure relates to battery charging. The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     Reducing total energy consumption and waste during a charge session for a battery may be a consideration for cost or environmental reasons. Some users may want to charge a battery with total energy consumption as a consideration. 
     BRIEF SUMMARY 
     Various disclosed embodiments include illustrative direct current (DC) fast charger (DCFC) controller units, DCFC systems, and methods. 
     In an illustrative embodiment, a direct current (DC) fast charger (DCFC) controller unit includes a controller. The controller includes a processor and computer-readable media. The computer-readable media is configured to store computer-executable instructions configured to cause the processor to: receive a maximum charge time duration to charge at least one battery to a desired state of charge responsive to an increased efficiency charge mode being enabled; determine an amount of energy used in a plurality of charge cycles for charging the at least one battery to the desired state of charge with charge time durations no longer than the maximum charge time duration; select a charge cycle for charging the at least one battery to the desired state of charge with a lowest amount of energy used; and cause the at least one battery to be charged with the selected charge cycle. 
     In another illustrative embodiment, a DCFC system includes an electrical power converter configured to convert alternating current (AC) electrical power to DC electrical power. The electrical power converter includes a controller including a processor and computer-readable media. The computer-readable media is configured to store computer-executable instructions configured to cause the processor to: receive a maximum charge time duration to charge at least one battery to a desired state of charge responsive to an increased efficiency charge mode being enabled; determine an amount of energy used in a plurality of charge cycles for charging the at least one battery to the desired state of charge with charge time durations no longer than the maximum charge time duration; select a charge cycle for charging the at least one battery to the desired state of charge with a lowest amount of energy used; and cause the at least one battery to be charged with the selected charge cycle. At least one electrical power dispenser assembly is electrically couplable to the electrical power converter and configured to dispense DC electrical power to at least one battery. 
     In another illustrative embodiment, a method includes: receiving a maximum charge time duration to charge at least one battery to a desired state of charge responsive to an increased efficiency charge mode being enabled; determining an amount of energy used in a plurality of charge cycles for charging the at least one battery to the desired state of charge with charge time durations no longer than the maximum charge time duration; selecting a charge cycle for charging the at least one battery to the desired state of charge with a lowest amount of energy used; and causing the at least one battery to be charged with the selected charge cycle. 
     The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Illustrative embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive. 
         FIG.  1    is a block diagram of an illustrative DCFC system. 
         FIG.  2 A  is a block diagram of an illustrative electrical power converter of the DCFC system of  FIG.  1   . 
         FIG.  2 B  is a block diagram of another illustrative electrical power converter of the DCFC system of  FIG.  1   . 
         FIG.  2 C  is a block diagram of another illustrative power converter and another illustrative electrical power dispenser assembly. 
         FIG.  3    is a block diagram of an illustrative electrical power dispenser assembly of the DCFC system of  FIG.  1   . 
         FIG.  4    is a block diagram of an illustrative electric vehicle. 
         FIG.  5    is a graph of charger efficiency versus charger load. 
         FIG.  6    is a graph of charging efficiency of an electric vehicle. 
         FIGS.  7 A and  7 B  are graphs of charge efficiency versus battery charge current and time to charge versus battery charge current, respectively, for an illustrative battery charging application. 
         FIGS.  7 C and  7 D  are graphs of charge efficiency versus battery charge current and time to charge versus battery charge current, respectively, for another illustrative battery charging application. 
         FIGS.  7 E and  7 F  are graphs of charge efficiency versus battery charge current and time to charge versus battery charge current, respectively, for another illustrative battery charging application. 
         FIGS.  7 G and  7 H  are graphs of charge efficiency versus battery charge current and time to charge versus battery charge current, respectively, for another illustrative battery charging application. 
         FIG.  8    is a flow chart of an illustrative method of charging a battery. 
     
    
    
     Like reference symbols in the various drawings generally indicate like elements. 
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. 
     Various disclosed embodiments include illustrative direct current (DC) fast charger (DCFC) controller units, DCFC systems, and methods. 
     By way of nonlimiting overview and referring to  FIG.  1   , in various embodiments an illustrative DCFC system  10  includes an electrical power converter  12  configured to convert alternating current (AC) electrical power to DC electrical power. The electrical power converter  12  includes a controller  14  including a processor  16  and computer-readable media  18 . The computer-readable media  18  is configured to store computer-executable instructions configured to cause the processor  16  to: receive a maximum charge time duration to charge at least one battery  57  ( FIG.  4   ), such as without limitation in an electric vehicle  20 , to a desired state of charge responsive to an increased efficiency charge mode being enabled; determine an amount of energy used in a plurality of charge cycles for charging the at least one battery  57  to the desired state of charge with charge time durations no longer than the maximum charge time duration; select a charge cycle for charging the at least one battery  57  to the desired state of charge with a lowest amount of energy used; and cause the at least one battery  57  to be charged with the selected charge cycle. At least one electrical power dispenser assembly  22  is electrically couplable to the electrical power converter  12  and configured to dispense DC electrical power to at least one battery  57 . 
     Still by way nonlimiting overview, it will be appreciated that, according to time available for charging the at least one battery  57 , various embodiments can charge the at least one battery  57  to full charge using an amount of energy that is less than the amount of energy that would have been used by charging at peak charge current. Thus, it will be appreciated that various embodiments can take advantage of situations in which time available for charging the at least one battery  57  to full charge may be longer than that using a peak charge current capability of the DCFC system  10 —thereby helping to avoid wasting energy by completing a charge sooner than is necessary. 
     Still by way of nonlimiting overview, although various embodiments are described herein in terms of an electric vehicle, vehicle load, state of charge, losses, and the like, it will be appreciated that various embodiments can apply to any battery, such as for example and without imitation, any residential or commercial electrical energy storage systems with a battery or with one or more banks of batteries and are not limited to electric vehicles. 
     Illustrative details of the DCFC system  10  and the electric vehicle  20  will be explained first by way of nonlimiting examples given by way of illustration only and not of limitation. Illustrative details regarding charging the at least one electric vehicle  20  to full charge using an amount of energy that is less than the amount of energy that would have been used at maximum charging power will be explained next by way of illustration only and not of limitation. It is again emphasized that a rechargeable battery load is given by way of illustration and not of limitation as the electric vehicle  20  and that disclosed subject matter encompasses any battery, such as for example and without imitation, any residential or commercial electrical energy storage systems with a battery or with one or more banks of batteries. 
     Still referring to  FIG.  1   , in various embodiments the DCFC system  10  includes Electric Vehicle Supply Equipment (EVSE)—a standard used for vehicle charging equipment. In such embodiments and as discussed above, the DCFC system includes the electrical power converter  12  (sometimes referred to as a power cabinet) that receives alternating current (AC) electrical power from the grid and converts the grid AC electrical power to DC electrical power. The electrical power converter  12  provides the DC electrical power to the at least one electrical power dispenser assembly  22 . Each electrical power dispenser assembly  22  includes a charge coupler  24  that is electrically connected to the electrical power dispenser assembly  22  and that is electrically connectable to the battery  57  to dispense DC electrical power to the battery  57 . 
     Referring additionally to  FIG.  2 A , in various embodiments the processor  16  may include a computer processing unit (CPU), a general purpose processor, a digital signal processor, a field programmable gate array, or the like, and/or any combination thereof. Processors are well known and further description of their construction and operation are not necessary for an understanding by a person of skill in the art of disclosed subject matter. 
     In various embodiments the computer-readable media  18  may include any suitable computer memory configured to store computer-executable instructions configured to cause the processor  16  to perform functions described herein. Given by way of non-limiting examples, the computer-readable media  18  may include any suitable volatile memory elements, such as without limitation random access memory (RAM), such as dynamic RAM (DRAM), static RAM (SRAM), static-dynamic RAM (SDRAM), and the like, nonvolatile memory elements such as without limitation read-only-memory (ROM), hard drive, tape, compact-disc ROM (CDROM), and the like, and combinations thereof. Moreover, the computer-readable media  18  may incorporate electronic, magnetic, optical, and/or other types of storage media as desired. 
     In various embodiments the electrical power converter  12  includes the controller  14  that is coupled to a communications hub  26 . In various embodiments the communications hub  26  may be configured to provide a controller  38  of the electrical power dispenser assembly  22  with signals from the controller  14 . The communications hub  26  may also be configured with a communications network connection which may be wired or wireless. Each of the electrical power dispenser assemblies  22  may be individually addressed by the communications hub  26 . 
     At least one DC power module  28  converts AC electrical power (from an AC electrical power input  30  which passes through a main breaker  32  before being sent to the DC power modules  28 ) to DC electrical power and a dispenser power module  34  (which provides working power to various electronics in the at least one electrical power dispenser assembly  22 ). 
     In various embodiments, the electrical power converter  12  may include up to five (5) or more DC power modules  28  as desired. However, it will be appreciated that each electrical power converter  12  may include any number of DC power modules  28  as desired for a particular application. In various embodiments, an output conduit  15  electrically connects each DC power module  28  to an associated electrical power dispenser assembly  22  that is configured to provide electrical power to an associated battery  57 . It will be appreciated that, in such embodiments, only one DC power module  28  is connectable to any one vehicle  20  at a time. 
     In various embodiments the controller  14  is configured to control the power output of each of the DC power modules  28 . In various embodiments, the electrical power converter  12  may use isolated power modules  28  that combine to achieve peak power outputs in excess of 300 kW. In such embodiments, the electrical power converter  12  has the capability to charge over 20 vehicles in an overnight dwell scenario. 
     Referring additionally to  FIG.  2 B , in various embodiments the DCFC system  10  is configured to electrically connect multiple DC power modules  28  in parallel to a single vehicle  20  to help permit the vehicle  20  to be charged at higher power. As shown in  FIG.  2 B , in such embodiments the DCFC system  10  includes the electrical power converter  12  and at least one electrical power dispenser assembly  22 , each of which includes a charge coupler  24 . As shown in  FIG.  2 B , in some embodiments each electrical power dispenser assembly  22  may include its own dispenser power module  34  that is configured to convert AC electrical power to low voltage DC electrical power. The electrical power converter  12  includes the main breaker  32 , the controller  14 , the processor  16 , the computer-readable media  18 , the communications hub  26 , and the DC power modules  28 , all as described above. If desired, in some other embodiments the electrical power converter  12  may include the dispenser power module  34  (instead of each electrical power dispenser assembly  22  including its own dispenser power module  34 ). 
     In such embodiments the DCFC system  10  includes any number of the DC power modules  28  and the electrical power dispenser assemblies  22  as desired. For example and given by way of illustration only and not of limitation, as shown in  FIG.  2 A  the DCFC system  10  may include six DC power modules  28  and three electrical power dispenser assemblies  22 . However, it is emphasized that the DCFC system  10  can include any number whatsoever of the DC power modules  28  and the electrical power dispenser assemblies  22  as desired for a particular application. No limitation to any number of the DC power modules  28  and the electrical power dispenser assemblies  22  is intended and no limitation to any number of the DC power modules  28  and the electrical power dispenser assemblies  22  is to be inferred. 
     In such embodiments, the electrical power converter  12  includes a switching matrix  35 . The switching matrix  35  is electrically interposed between the DC power modules  28  and the electrical power dispenser assemblies  22 . In some embodiments the switching matrix  35  may be coupled to receive a control signal  37  from the controller  14  (such as, for example, via the communications hub  26 ) to control connection of various DC power converters  28  to various electrical power dispenser assemblies  22 . In some other embodiments, the DC power modules  28  may control the switching matrix  35 . Regardless of method of controlling the switch matrix  35 , in various embodiments, any number of the DC power modules  28  (from one of the DC power modules  28  to all of the DC power modules  28 ) can be electrically connected to any of the electrical power dispenser assemblies  22 . In various such embodiments, the switching matrix  35  suitably may include any suitable switches that are controllable (by the controller  14 ) to connect the selected DC power converter(s)  28  to a selected electrical power dispenser assembly  22 . In some embodiments the switching matrix  35  may include separate single pole switches for positive terminals and separate single pole switches for negative terminals. In some other embodiments, if desired the switching matrix  35  may include double-pole, single-throw (DPST) switches for positive and negative terminals. 
     In such embodiments, any number of the DC power modules  28  as desired can be electrically connected in parallel to any one of the electrical power dispenser assemblies  22  by the switching matrix  35 . It will be appreciated that any number of the DC power modules  28  as desired can be selected to be electrically connected to the selected electrical power dispenser assembly  22  by the switching matrix  35 . In some instances there may be an upper limit to the number of DC power modules  28  that are available (that is, that are free for use and that can be used to charge the vehicle  20  via the selected electrical power dispenser assembly  22 ). It will be appreciated that the available DC power modules  28  may be enabled or disabled as desired for achieving a desired charging efficiency. 
     Referring additionally to  FIG.  2 C  and given by way of other non-limiting example, in various other embodiments the DCFC system  10  may include more than one electrical power dispenser assembly  22  electrically connected in series. That is, as shown in  FIG.  2 C , the electrical power dispenser assemblies  22  may be “daisy-chained” in serial electrical connection. Thus, in various embodiments, the at least one electrical power dispenser assembly  22  may include more than one electrical power dispenser assembly  22  and the at least one battery  57  may include more than one battery  57 . Given by way of non-limiting example and as shown in  FIG.  2 C , in various embodiments the DCFC system  10  may include more than one electrical power dispenser assembly  22  electrically connected in series. As such, in a fleet application, the DCFC system  10  has the capability to chain several electrical power dispenser assemblies  22  in series fashion. For example, in such embodiments the DCFC system  10  can perform a similar calculation for the entire chain of electric vehicles  20 . As such, it will be appreciated that all of the vehicles  20  may be fully charged within the allocated charge time while consuming a reduced amount of energy. 
     Referring additionally to  FIG.  3   , in various embodiments the electrical power dispenser assembly  22  includes a conduit input  36 , a controller  38 , a power supply  40 , the charge coupler  24 , and a switching unit  42 . In various embodiments, a human-machine interface (HMI)  43  (such as, without limitation, a touch screen display or the like) is coupled to the controller  38 . The switching unit  42  includes a switch  42 A. The switching unit  42  may be controlled by the controller  38 . The controller  38  and the switching unit  42  are configured to control the provision of electrical power to the charge coupler  24  via the switch  42 A. In such embodiments the switch  42 A may include any suitable switch as desired. For example, in some embodiments the switch  42 A may include a double-pole, single throw (DPST) switch for positive and negative terminals. As another example, the switch  42 A may be implemented as separate single pole switches (that is, a separate single pole switch for positive terminals and a separate single pole switch for negative terminals). In various embodiments the charge coupler  24  suitably may include a combined charging system (CCS) Type 1 and/or Type 2 coupler, a CHAdeMo coupler, a GB/T coupler, a Tesla connector, and/or the like. 
     In various embodiments the controller  14  may be configured to generate control signals  44 A,  44 B,  44 C,  44 D, and  44 E ( FIG.  2   ) for the controller  38  of associated dispensers  16  and thereby control the power output to each of the dispensers  16 . Again, while five control signals are illustrated in this non-limiting example, it will be appreciated that any number of dispensers  16  and associated control signals may be used as desired for a particular application. The communications hub  26  may be configured to provide the controllers  38  with the control signals  44 A,  44 B,  44 C,  44 D, and  44 E from the controller  14 . 
     In various embodiments the charge coupler  24  is electrically connected to the electrical power dispenser assembly  22  via a cable  47 . It will be appreciated that in various embodiments the cable  47  is a cable bundle that includes wiring that provides control signals to and from the charge coupler  24  and cabling that provides DC electrical power to the charge coupler  24 . 
     The communications hub  26  may also be configured with a communications network connection ( FIG.  1   ) which may be wired or wireless. Each of the electrical power dispenser assemblies  22  may be individually addressed by the communications hub  26 . Each of the electrical power dispenser assemblies  22  may also have dispenser identifiers associated therewith to facilitate communications (such as, without limitation, information regarding time available for charging the at least one battery  57 ) between the controller  38  ( FIG.  2   ) and the communications hub  26 . 
     In various embodiments and as shown in  FIG.  1   , the communications hub  26  may be connected to and communicate with at least one server  45  via a communications network  46  such as but not limited to the Internet. In various embodiments the communications hub  26  may include a radio transceiver (not shown) and a radio frequency antenna  48  that is electrically connected to the radio transceiver. The radio transceiver may be configured to send and receive via various communication protocols including but not limited to Wi-Fi, Bluetooth, Bluetooth Low Energy (BLE), and the like. In some embodiments, the vehicle  20  may include a BLE transceiver  50  configured to communicate a vehicle identifier and any other information (such as, without limitation, identification of owner of a vehicle or identification of a user who is performing the charging operation) with the communications hub  26  via a BLE link  52 . Further, the communications hub  26  may also communicate over a Wi-Fi link  54  with a Wi-Fi access point  56  that, in turn, communicates with one or more computer processors or one or more of the computer servers  45  over the communications network  46 . 
     Referring additionally to  FIG.  4   , in various embodiments the at least one electric vehicle  20  includes a battery  57 . In various embodiments the battery  57  includes a high-voltage DC electrical battery. In such embodiments, the battery  57  is configured to provide high-voltage DC electrical power, such as on the order of around 450 volts or so. In various embodiments the battery  57  may include a lithium-ion battery. However, it will be appreciated that the battery  57  may include any suitable battery as desired and that further description of the battery  57  is not necessary for a person of skill in the art to understand disclosed subject matter. 
     It is again emphasized that the rechargeable load is given by way of illustration and not of limitation as the electric vehicle  20  and that disclosed subject matter encompasses any battery, such as for example and without imitation, any residential or commercial electrical energy storage systems with a battery or with one or more banks of batteries. 
     In various embodiments the at least one electric vehicle  20  includes an electronics control unit (ECU)  58  that controls operations of various components via a peer-to-peer network bus  60  such as a controller area network (CAN) bus. Other peer-to-peer network buses, such as a local area network (LAN), a wide area network (WAN), or a value-added network (VAN), may also be used for enabling communication between the ECU  58  and the components connected to the peer-to-peer network bus  60 . In various embodiments the ECU  58  communicates via the peer-to-peer network bus  60  with a human-machine interface (HMI)  62 , a battery management unit (BMU)  64 , and one or more drive units  66 . 
     In various embodiments and given by way of example only and not of limitation, the HMI  62  may include mechanical buttons or switches or may include selectable graphical user interface features presented on a vehicle display device(s). 
     In various embodiments and given by way of example only and not of limitation, the BMU  64  communicates with the battery  57  to generate battery status information, which is sent to the ECU  58  via the peer-to-peer network bus  60 . The BMU  64  receives battery information from the battery  57  and/or from any sensors (not shown for purposes of clarity) associated with or included in the battery  57 . The battery information may include state of charge (SOC), temperature, voltage of battery cells, input/output current, coolant flow, or other values related to battery operations. The BMU  64  uses the battery information to control battery recharging and battery thermal management and to communicate with other components of the vehicle  20  via the peer-to-peer network bus  60  or with external components, such as without limitation the DCFC system  10  or other systems or devices. 
     In various embodiments the drive unit  66  may include one or more inverters  68 , one or more position sensors  70  such as a resolver, and one or more electric motors  72 , such as without limitation brushless direct current (BLDC) motors, alternating current induction motors (ACIM), permanent magnet (PM) synchronous motors (PMSM), interior PM motors (IPMM), PM switch reluctance motors (PMSRM), or any suitable electrical motors whatsoever as desired. A drive member  74  is rotatably coupled to the electric motor  72 . At least one propulsion device  76  is coupled to the drive member  74 . 
     In various embodiments the ECU  58  may include a data processor and computer-readable media configured to store computer-executable instructions configured to cause the data processor to perform various functions. For example, in various embodiments the computer-executable instructions are configured to cause the data processor to generate vehicle status information from data received from the HMI  62 , the BMU  64 , the drive unit  66 , or other devices and to provide the vehicle status information via the charge coupler  24  and/or the BLE transceiver  50 . 
     In response to the generation of the vehicle status information, the computer-executable instructions are configured to cause the data processor of the ECU  58  to generate control signals for the various other vehicle components, such as the BMU  64 , the drive unit  66 , or the like to perform various functions. In various embodiments, control signals for controlling the drive unit(s)  66  may, in turn, be executed by a controller (not shown) within the drive unit  66  and having a processor directly connected to the inverter(s)  68  and the position sensor(s)  70 . In such embodiments, the controller included within the drive unit  66  may include computer-readable media configured to store computer-executable instructions configured to cause the processor included within the drive unit  66  to perform some or all of the functions described herein. The controller included within the drive unit  66  may communicate with the ECU  58  and other components via the peer-to-peer network bus  60 . 
     In various embodiments and given by way of example only and not of limitation, the vehicle  20  includes a DC fast charging connector  78 . In such embodiments the DC fast charging connector  78  may apply DC electrical power from an external DC fast charging unit (such as, for example, the DCFC system  10 ) via the charge coupler  24  to the battery  57  in response to communication with the BMU  64  and may apply applicable control signals via the charge coupler  24  to various components connected to the peer-to-peer network bus  60 . 
     It will be appreciated that the vehicle  20  can be any type of vehicle whatsoever as desired without limitation. Given by way of non-limiting example, in various embodiments the vehicle  20  may be an electric vehicle (that is, an all-electrically driven vehicle) or a hybrid vehicle. For example and given by way of non-limiting examples, in various embodiments the vehicle  20  may include a motor vehicle driven by wheels and/or tracks, such as, without limitation, an automobile, a truck, a sport utility vehicle (SUV), a van, an all-terrain vehicle (ATV), a motorcycle, an electric bicycle, a tractor, a lawn mower such as without limitation a riding lawn mower, a snowmobile, and the like. Given by way of further non-limiting examples, in various embodiments the vehicle  20  may include a marine vessel such as, without limitation, a boat, a ship, a submarine, a submersible, an autonomous underwater vehicle (AUV), and the like. Given by way of further non-limiting examples, in various embodiments the vehicle  20  may include an aircraft such as, without limitation, a fixed wing aircraft, a rotary wing aircraft, and a lighter-than-air (LTA) craft. 
     In various embodiments the electric motor (or motors)  72  is configured to drive the vehicle  20 . That is, in various embodiments the electric motor (or motors)  72  may drive any drive member  74  that drives any propulsion device  76 , such as without limitation a wheel or wheels, a track or tracks, a propellor or propellors, a propulsor or propulsors, a rotor or rotors, or the like, associated with the vehicle  20 . 
     For example, in some embodiments in a motor vehicle one electric motor  72  may be configured to drive one drive member  74  such as an axle or a chain ring that drives one wheel or track, in some other embodiments in a motor vehicle one electric motor  72  may be configured to drive an axle that rotates two wheels or two tracks, and in some other embodiments in a motor vehicle one electric motor  72  may be configured to drive an axle that rotates one wheel or one track and another motor configured to drive another axle that rotates another wheel or another track. 
     Similarly, in some embodiments in a marine vessel one electric motor  72  may be configured to drive one propeller or propulsor, in some other embodiments in a marine vessel one electric motor  72  may be configured to drive a shaft that rotates two propellers or two propulsors, and in some other embodiments in a marine vessel one electric motor  72  may be configured to drive a shaft that rotates one propeller or propulsor and another electric motor  72  may be configured to drive another shaft that rotates another propeller or propulsor. 
     Likewise, in some embodiments in an aircraft one electric motor  72  may be configured to drive one propeller or rotor, in some other embodiments in an aircraft one electric motor  72  may be configured to drive a shaft that rotates two propellers or two rotors, and in some other embodiments in an aircraft one electric motor  72  may be configured to drive a shaft that rotates one propeller or rotor and another electric motor  72  may be configured to drive another shaft that rotates another propeller or rotor. 
     Now that illustrative, non-limiting embodiments of the DCFC system  10  and the electric vehicle  20  have been explained by way of nonlimiting examples given by way of illustration only and not of limitation, illustrative details regarding charging the at least one battery  57  to full charge using an amount of energy that is less than the amount of energy that would have been used at maximum charging power will be explained next by way of illustration only and not of limitation. 
     Referring additionally to  FIG.  5   , an example curve  80  plots efficiency of the DCFC system  10  along a y axis versus load (that is, charge power) of the DCFC system  10 . As shown in  FIG.  5   , efficiency of the DCFC system  10  rapidly increases to around ninety-six percent as load percentage increases up to around ten percent or so. As shown in  FIG.  5   , efficiency of the DCFC system  10  levels off at a maximum efficiency of around ninety-seven percent or so at a load percentage of around twenty-five percent to thirty percent and gradually decreases in a substantially linear manner to an efficiency of ninety-five percent or so at one hundred percent load (that is, peak charge current). Thus, it will be appreciated that the DCFC system  10  is not operating at maximum efficiency at peak charging current. Instead, it will be appreciated that the DCFC system  10  is operating at maximum efficiency at a load percentage of around twenty-five percent to thirty percent (that is, at a charge current of around twenty-five percent to thirty percent of peak charge current). As shown in  FIG.  5   , the DCFC system  10  is about two percent less efficient at peak charge current that at a charge current of around twenty-five percent to thirty percent of peak charge current. Thus, in various embodiments the DCFC system  10  can charge the at least one battery  57  at a charge current less than peak charge current when sufficient time is available. As a result, in various embodiments the DCFC system  10  can charge the at least one battery  57  at a higher efficiency than that at peak charge current. Thus, in various embodiments the DCFC system  10  can use less electrical power to charge the at least one battery  57  than would be used to charge the at least one battery  57  using peak charge current. 
     Still referring to  FIGS.  1 ,  2 A,  2 B, and  3 - 5    and in view of gains in efficiency of the DCFC system  10  at charge current less than peak charge current, various embodiments can operate as follows. 
     In various embodiments, a user can enable or disable an increased efficiency charge mode. In such embodiments, an increased efficiency charge mode is a charge mode that charges the battery  57  to a desired state-of-charge (SOC) with charge current less than peak charge current in a time longer than time to charge the battery  57  to the desired SOC using peak charge current. 
     At commencement of a charging operation, in various embodiments the instructions may cause the processor  16  to cause the controller  38  to cause a user to be prompted to enter a desired SOC. For example, in some embodiments the instructions may cause the processor  16  to cause the controller  38  to cause the HMI  43  of the electrical power dispenser assembly  22  to prompt a user to enter a desired SOC. In some other embodiments the instructions may cause the processor  16  to cause (via the electrical power dispenser assembly  22 , the ECU  58 , and the peer-to-peer network bus  60 ) the HMI  62  of the electric vehicle  20  to prompt a user to enter a desired SOC. It will be appreciated that the desired SOC may be entered in any format as desired, such as without limitation percentage of charge for the battery  57 , usable time of the battery  57 , distance travelable, or the like. 
     In some embodiments the instructions may cause the processor  16  to cause the controller  38  to cause the HMI  43  of the electrical power dispenser assembly  22  to present to a user an option to enable an increased efficiency charge mode or to disable an increased efficiency charge mode. As another example, in some other embodiments the instructions may cause the processor  16  to cause (via the electrical power dispenser assembly  22  and the peer-to-peer network bus  60 ) the HMI  62  of the electric vehicle  20  to present to a user an option to enable increased efficiency charge mode or to disable increased efficiency charge mode. 
     In such embodiments, when an increased efficiency charge mode is disabled the instructions cause the processor  16  to cause the DCFC system  10  to charge the at least one battery  57  to the desired SOC using peak charge current—that is, at a maximum charging rate within system limits. Further description is not necessary for a person of skill in the art to understand charging the at least one battery  57  using peak charge current. 
     In various embodiments, with an increased efficiency charge mode enabled, the instructions cause the processor  16  to perform functions as set forth below. 
     In various embodiments, when an increased efficiency charge mode is enabled, a user may be prompted to enter a maximum charge time duration. For example, in some such embodiments the instructions may cause the processor  16  to cause the controller  38  to cause the HMI  43  of the electrical power dispenser assembly  22  to prompt a user to enter a maximum charge time duration. In some other such embodiments the instructions may cause the processor  16  to cause (via the electrical power dispenser assembly  22  and the peer-to-peer network bus  60 ) the HMI  62  of the electric vehicle  20  to prompt a user to enter a maximum charge time duration. Regardless, in such embodiments the user enters a maximum charge time duration via the HMI  43  of the electrical power dispenser assembly  22  or the HMI  62  of the electric vehicle  20 , as appropriate. Given by way of non-limiting examples, the maximum charge time duration may be entered in any suitable format, such as without limitation hours (with any number of decimal points as desired), hours and minutes, minutes, or the like, as desired. 
     It will be appreciated that, in some embodiments, a maximum charge time duration may be provided by an automated system (such as, without limitation, the processor  16 ) based upon factors such as time entailed in charging the battery  57  to the desired SOC, for example, based on a maximum charging rate within the limitations of the DCFC system  10 . For example, in some embodiments the maximum charge time duration may be based on the maximum time available to charge the at least one battery  57  vehicle before a user desires to drive the electric vehicle  20  or before an automated system (such as, without limitation, the processor  16 ) determines that the DCFC system  10  is unavailable. 
     With a desired (or otherwise) SOC entered, an increased efficiency charge mode enabled, and a maximum charge time duration entered, in various embodiments the instructions may cause the processor  16  to perform further functions as set forth below. 
     In view of the desired SOC entered, an increased efficiency charge mode being enabled, and a maximum charge time duration entered, in various embodiments the processor  16  may determine an amount of energy used in charge cycles for charging the at least one battery  57  to the desired state of charge with charge time durations no longer than the maximum charge time duration. 
     In some such embodiments, the processor  16  may determine an amount of energy used in charge cycles for charging the at least one battery  57  to the desired state of charge with charge time durations no longer than the maximum charge time duration responsive to efficiency of the DCFC system  10 , efficiency of the at least one battery  57 , and maximum charge time duration. 
     For example, efficiency of the DCFC system  10  may be determined responsive to electrical power losses within the DCFC system  10 —such as, without limitation, electrical power conversion losses, bias and housekeeping power usage—that is ancillary power entailed to perform charging with the DCFC system  10  such as without limitation power for contactor coils, protection devices, gate drivers, and the like, cooling pump power usage, cooling fan power usage, controller power usage, display power usage, and/or the like. As such, in various embodiments the DCFC system  10  already knows its own efficiency characteristics. Thus, these efficiency characteristics are accounted for in the efficiency calculation of the DCFC system  10 . In addition, in various embodiments the processor  16  may cause a cooling pump and/or a cooling fan to operate at a reduced speed. 
     In addition, data regarding efficiency of the at least one battery  57  may be provided in a data format such as an efficiency curve and effective charge resistance. For example and referring additionally to  FIG.  6   , in various embodiments, the vehicle  20  may provide charge cycle efficiency data to the DCFC system  10 . As shown in  FIG.  6   , in various embodiments an illustrative vehicle charging efficiency curve is plotted as a function of charge rate (that is, charge current divided by a battery&#39;s capacity to store an electrical charge (“C-rate”)) and initial state of charge (SOC). The charge rate is shown on an x-axis and the charge cycle efficiency is plotted on a y-axis. As shown in  FIG.  6   , vehicle charging efficiency generally decreases as the charge rate is increased. It will be appreciated that in various embodiments the vehicle charging efficiency curve may incorporate information regarding on-vehicle parasitic loads, such as without limitation pumps and fans, which can help improve accuracy and fidelity of predicted vehicle efficiency. 
     In some other embodiments, the vehicle  20  may provide information in a simplified form, such as an equivalent charge resistance. In such embodiments, the DCFC system  10  can compute the vehicle side losses as the square of the charging current times the effective charging resistance. 
     Referring additionally to  FIGS.  7 A- 7 H , in various embodiments the processor  16  determines charge cycles that can charge the at least one battery  57  to the desired SOC within the maximum charge time duration. As discussed above, such charge cycles can entail charging at less than the maximum charge rate of the DCFC system  10  and, thus, can use less electrical power to charge the at least one vehicle  20  to the desired SOC. 
     As will be explained below with reference to  FIGS.  7 A- 7 H , in various embodiments the processor  16  may determine an amount of energy used in charge cycles in charging the at least one vehicle  20  to the desired SOC within the maximum charge time duration. The processor  16  may select a charge cycle for charging the at least one battery  57  to the desired state of charge with a lowest amount of energy used and may cause the at least one battery  57  to be charged with the selected charge cycle. 
     In some instances, the charge cycle selected for charging the at least one battery  57  to the desired state of charge with a lowest amount of energy used can include a charge cycle performed using less than a maximum charge power capability of the DCFC system  10 . In such instances, the processor  16  has determined that the battery  57  can be charged to the desired state of charge within the maximum charge time duration. 
     In some other instances, the charge cycle selected for charging the at least one battery  57  to the desired state of charge with a lowest amount of energy used may include a charge cycle performed using the maximum charge power capability of the DCFC system  10 . That is, in such instances, the processor  16  has determined that the at least one battery  57  can be charged to the desired state of charge within the maximum charge time duration only by charging with the maximum charge power capability of the DCFC system  10 . 
     Several non-limiting scenarios will now be explained by way of non-limiting examples set forth by way of illustration only and not of limitation. 
     Given by way of non-limiting example and as shown in  FIGS.  7 A and  7 B , in a first scenario a SOC charge request of 20-100 percent has been entered and a maximum charge time duration of one hour has been entered. Up to six DC power modules  28  are available for charging, and maximum charging current is limited by a charging cable. 
     As shown in  FIG.  7 A , charging efficiency is plotted along a y-axis for a number N of DC power modules  28  electrically connected in parallel versus battery charge current (normalized to maximum charging current) along an x-axis. 
     As shown in  FIG.  7 B , the charge current entailed in completing the charge in one hour is determined to be 0.6 maximum charge current (normalized). 
     As shown in  FIG.  7 A , with battery charge current at 0.6 maximum charge current (normalized), three or more DC power modules  28  electrically connected in parallel are entailed in completing the charge to the target SOC within the maximum charge time duration of one hour (that is, N is greater than or equal to 3). In this scenario and as shown in  FIG.  7 A , less than three DC power modules  28  (that is, one or two DC power modules  28 ) are not able to complete the charge to the target SOC within the maximum charge time duration of one hour. 
     As shown in  FIG.  7 A , six DC power modules  28  electrically connected in parallel result in a maximized charge efficiency and six DC power modules  28  electrically connected in parallel are selected to perform the charge. In various embodiments, the processor  16  causes the switching matrix  35  to electrically connect the six DC power modules  28  to the selected electrical power dispenser assembly  22 . The processor  16  sets total charge current to 0.6 times maximum charge current and sets current per DC power module to ⅙ the total charge current. It will be appreciated that, as shown in  FIG.  7 A , charge efficiency in this scenario is around 94.8 percent. 
     Given by way of non-limiting example and as shown in  FIGS.  7 C and  7 D , in a second scenario a SOC charge request of 20-100 percent has been entered and a maximum charge time duration of two hours has been entered. Up to six DC power modules  28  are available for charging, and maximum charging current is limited by a charging cable. 
     As shown in  FIG.  7 C , charging efficiency is plotted along a y-axis for a number N of DC power modules  28  electrically connected in parallel versus battery charge current (normalized to maximum charging current) along an x-axis. 
     As shown in  FIG.  7 D , the charge current entailed in completing the charge in two hours is determined to be 0.3 maximum charge current (normalized). 
     As shown in  FIG.  7 C , with battery charge current at 0.3 maximum charge current (normalized), two or more DC power modules  28  electrically connected in parallel are entailed in completing the charge to the target SOC within the maximum charge time duration of two hours (that is, N is greater than or equal to 2). In this scenario and as shown in  FIG.  7 C , less than two DC power modules  28  (that is, one DC power module  28 ) is not able to complete the charge to the target SOC within the maximum charge time duration of two hours. 
     As shown in  FIG.  7 C , four or five or six DC power modules  28  electrically connected in parallel can result in about a substantially similar maximized charge efficiency and four DC power modules  28  electrically connected in parallel are selected to perform the charge. In various embodiments, the processor  16  causes the switching matrix  35  to electrically connect the four DC power modules  28  to the selected electrical power dispenser assembly  22 . The processor  16  sets total charge current to 0.3 times maximum charge current and sets current per DC power module to ¼ the total charge current. It will be appreciated that, as shown in  FIG.  7 C , charge efficiency in this scenario is around 96 percent. 
     Given by way of non-limiting example and as shown in  FIGS.  7 E and  7 F , in a third scenario a SOC charge request of 20-100 percent has been entered and a maximum charge time duration of six hours has been entered. Up to six DC power modules  28  are available for charging, and maximum charging current is limited by a charging cable. 
     As shown in  FIG.  7 E , charging efficiency is plotted along a y-axis for a number N of DC power modules  28  electrically connected in parallel versus battery charge current (normalized to maximum charging current) along an x-axis. 
     As shown in  FIG.  7 F , the charge current entailed in completing the charge in six hours is determined to be 0.1 maximum charge current (normalized). 
     As shown in  FIG.  7 E , with battery charge current at 0.1 maximum charge current (normalized), any number of the DC power modules  28  electrically connected in parallel can complete the charge to the target SOC within the maximum charge time duration of six hours (that is, N is greater than or equal to 1). 
     As shown in  FIG.  7 E , two DC power modules  28  electrically connected in parallel can result in a maximized charge efficiency and two DC power modules  28  electrically connected in parallel are selected to perform the charge. In various embodiments, the processor  16  causes the switching matrix  35  to electrically connect the two DC power modules  28  to the selected electrical power dispenser assembly  22 . The processor  16  sets total charge current to 0.1 times maximum charge current and sets current per DC power module to ½ the total charge current. It will be appreciated that, as shown in  FIG.  7 E , charge efficiency in this scenario is around 96.5 percent. 
     Given by way of non-limiting example and as shown in  FIGS.  7 G and  7 H , in a fourth scenario a SOC charge request of 20-100 percent has been entered and a maximum charge time duration of four hours has been entered. Only one DC power module  28  is available for charging. 
     As shown in  FIG.  7 G , charging efficiency is plotted along a y-axis for one DC power module  28  versus battery charge current (normalized to maximum charging current) along an x-axis. 
     As shown in  FIG.  7 H , the charge current entailed in completing the charge in four hours is determined to be 0.36 maximum charge current (normalized). 
     As shown in  FIG.  7 G , with battery charge current at 0.36 maximum charge current (normalized), one of the DC power modules  28  can complete the charge to the target SOC within the maximum charge time duration of four hours. 
     As shown in  FIG.  7 G , one of the DC power modules  28  can result in a maximized charge efficiency and one of the DC power modules  28  is selected to perform the charge. In various embodiments, the processor  16  causes the switching matrix  35  to electrically connect the one selected DC power module  28  to the selected electrical power dispenser assembly  22 . The processor  16  sets total charge current to 0.36 times maximum charge current and sets current per the one selected DC power module to the total charge current. It will be appreciated that, as shown in  FIG.  7 G , charge efficiency in this scenario is around 96.3 percent (as opposed to charging efficiency at maximum charging current, which would yield only 93.5 percent efficiency). It will be appreciated that allowing a longer charge time can help improve efficiency. 
     Referring additionally to  FIG.  8   , in various embodiments a method  800  starts at a block  802 . At a block  804  a desired state of charge is received. At a block  806  a determination is made whether an increased efficiency charge mode is enabled. At a block  808 , at least one battery is charged at a maximum charging rate responsive to an increased efficiency charge mode not being enabled, and the method  800  ends at a block  810 . At a block  812  a maximum charge time duration to charge at least one battery to a desired state of charge is received responsive to an increased efficiency charge mode being enabled. At a block  814  an amount of energy used in a plurality of charge cycles for charging the at least one battery to the desired state of charge with charge time durations no longer than the maximum charge time duration is determined. At a block  816  a charge cycle for charging the at least one battery to the desired state of charge with a lowest amount of energy used is selected. At a block  818  the at least one battery is caused to be charged with the selected charge cycle, and the method  800  ends at a block  910 . 
     In various embodiments selecting a charge cycle for charging the at least one battery to the desired state of charge with a lowest amount of energy used at the block  816  may include selecting a charge cycle performed using less than a maximum charge power capability of a charging system. 
     In various embodiments selecting a charge cycle for charging the at least one battery to the desired state of charge with a lowest amount of energy used at the block  816  may include selecting a charge cycle performed using a maximum charge power capability of a charging system. 
     In some instances, one or more components may be referred to herein as “configured to,” “configured by,” “configurable to,” “operable/operative to,” “adapted/adaptable,” “able to,” “conformable/conformed to,” etc. Those skilled in the art will recognize that such terms (for example “configured to”) generally encompass active-state components and/or inactive-state components and/or standby-state components, unless context requires otherwise. 
     While particular aspects of the present subject matter described herein have been shown and described, it will be apparent to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from the subject matter described herein and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of the subject matter described herein. It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (for example, bodies of the appended claims) are generally intended as “open” terms (for example, the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to claims containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (for example, “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (for example, the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (for example, “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that typically a disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms unless context dictates otherwise. For example, the phrase “A or B” will be typically understood to include the possibilities of “A” or “B” or “A and B.” 
     The foregoing detailed description has set forth various embodiments of the devices and/or processes via the use of block diagrams, flowcharts, and/or examples. Insofar as such block diagrams, flowcharts, and/or examples contain one or more functions and/or operations, it will be understood by those within the art that each function and/or operation within such block diagrams, flowcharts, or examples can be implemented, individually and/or collectively, by a wide range of hardware. 
     With respect to the appended claims, those skilled in the art will appreciate that recited operations therein may generally be performed in any order. Also, although various operational flows are presented in a sequence(s), it should be understood that the various operations may be performed in other orders than those which are illustrated or may be performed concurrently. Examples of such alternate orderings may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, supplemental, simultaneous, reverse, or other variant orderings, unless context dictates otherwise. Furthermore, terms like “responsive to,” “related to,” or other past-tense adjectives are generally not intended to exclude such variants, unless context dictates otherwise. 
     While the disclosed subject matter has been described in terms of illustrative embodiments, it will be understood by those skilled in the art that various modifications can be made thereto without departing from the scope of the claimed subject matter as set forth in the claims.