WO2025254993A1

WO2025254993A1 - Bi-directional charging and discharging of a battery electric machine

Info

Publication number: WO2025254993A1
Application number: PCT/US2025/031864
Authority: WO
Inventors: Dustin C. Selvey; Amara Ashfaq; Sindhu KARNATI; Swadi SUNDARESAN; Gayatri MACHA; Adam K. BENEDICT; Basheer Qattum; Gabriel F. COTO; Julianna DELGADO
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2024-06-08
Filing date: 2025-06-02
Publication date: 2025-12-11
Anticipated expiration: 2026-12-08

Abstract

An energy storage system for a battery electric machine (BEM) includes a battery system; a charging path connecting a charging cable receptacle of the BEM and the battery system; a discharging path connecting the charging cable receptacle of the BEM and the battery system; and a charger interface controller (CIC) operatively coupled to the battery system. The CIC is configured to send a request to another controller for charging the BEM; enable the charging path in response to a charging confirmation message received from the other controller; send a request to the other controller for discharging the BEM; and enable the discharging path in response to a discharging confirmation message received from the other controller.

Description

BI-DIRECTIONAL CHARGING AND DISCHARGING OF A BATTERY ELECTRIC MACHINE

Technical Field

This document relates to electric powered work machines and in particular to a Megawatt class charging system for charging the energy source of battery electric machines.

Background

Powering a large moving work machine (e.g., a wheel loader, a mining truck, etc.) with one or more electric motors requires a large mobile electric energy source that can provide current of thousands of Amperes (Amps). An example of a mobile energy source is a battery system containing multiple strings of high-capacity batteries. The batteries in each string are connected in series, and the strings of batteries are connected in parallel to provide the high output power needed by the electric work machines. The mobile energy source needs to be recharged when the energy source nears depletion. Different battery electric machines may have different power needs and charging needs.

Summary of the Invention

Electric powered large moving work machines use large capacity battery systems that need charging, and it is desirable to provide the charging at a remote job site. However, the machines at the job site may have different charging needs. It would be advantageous for a single charging system to meet the different charging needs of the different types of machines, and to meet discharging needs of the different types of machines.

An example bi-directional charging system for a battery electric machine (BEM) includes a battery system; at least one contactor connecting a charging cable receptacle of the BEM and the battery system; and a charger interface controller (CIC) operatively coupled to the battery system. The CIC configured to send a request to another controller for charging the BEM; enable charging of the battery system via the charging cable receptacle in response to a charging confirmation message received from the other controller; send a request to the other controller for discharging the BEM; and enable discharging of the battery system via the charging cable receptacle in response to a discharging confirmation message received from the other controller.

An example method of operating a charging system for a BEM includes charging a battery system of the BEM using charge energy from at least one charger device of the charging system; and discharging the battery system of the BEM by sending discharge energy from the battery system of the BEM to the at least one charger device. The discharging includes the at least one charger device regulating the discharge energy according to a maximum discharge current.

An example charge dispenser device to charge a BEM includes multiple charger input receptacles, a cable connector to connect to a charging cable for the BEM, and a dispenser controller. The charger input receptacles are configured to receive electrical energy from a plurality of charger devices that are each configured to provide energy to charge the BEM. The dispenser controller is configured to receive a charging request from a charger interface controller (CIC) of the BEM, wherein the charging request includes charging information for the BEM; send a charging confirmation message to the CIC; receive a discharging request from the CIC of the BEM; and send a discharging confirmation message to the CIC wherein the charging confirmation message includes a value of maximum discharge current.

Brief Description of the Drawings

FIG. 1 is an elevation view depicting an example work machine in accordance with this disclosure.

FIG. 2 illustrates an example of a bi-directional charging system for battery electric machines in accordance with this disclosure.

FIG. 3 is a block diagram of the example of the bi-directional charging system of FIG. 2 in accordance with this disclosure. FIG. 4 is a flow diagram of an example of a method of operating a bi-directional charging system for a BEM in accordance with this disclosure.

FIG. 5 is a flow diagram of an example of a method of operating a bi-directional charging system for a BEM in accordance with this disclosure.

FIG. 6 illustrates another example of a bi-directional charging system for battery electric machines in accordance with this disclosure.

FIG. 7 is a block diagram of portions of the example of the bidirectional charging system of FIG. 6 in accordance with this disclosure.

FIG. 8 is a diagram of an example of communication networks for charger devices and a charge dispenser of a charging system in accordance with this disclosure.

FIG. 9 is a flow diagram of another example of a method of operating a bi-directional charge dispenser in accordance with this disclosure.

Detailed Description

Examples according to this disclosure are directed to methods and devices that improve charging and discharging of a rechargeable energy source of a battery electric work machine.

FIG. 1 depicts an example machine 100 in accordance with this disclosure. In FIG. 1, machine 100 includes frame 102, wheels 104, implement 106, and a speed control system implemented in one or more on-board electronic devices like, for example, an electronic control unit or ECU. Example machine 100 is a material hauler that is a large mining truck. In other examples, however, the machine may be other types of machines related to various industries, including, as examples, construction, agriculture, forestry, transportation, material handling, waste management, marine, stationary power, and so on. Accordingly, although some examples are described with reference to a material hauler machine, examples according to this disclosure are also applicable to other types of machines.

Machine 100 includes frame 102 mounted on four wheels 104, although, in other examples, the machine could have more than four wheels. Frame 102 is configured to support and/or mount one or more components of machine 100. For example, machine 100 can house, among other components, an electric motor to propel the machine over various terrain via wheels 104. In some examples, multiple electric motors are included in multiple enclosures at multiple locations of the machine 100.

Machine 100 includes implement 106 coupled to the frame 102 through linkage assembly 110, which is configured to be actuated to articulate bucket 112. Bucket 112 may be configured to transfer material such as, soil, ore, or debris, from one location to another. Linkage assembly 110 can include one or more cylinders configured to be actuated hydraulically or pneumatically, for example, to articulate bucket 112. For example, linkage assembly 110 can be actuated by cylinders to raise and lower bucket 112 relative to frame 102 of machine 100.

Machine 100 also includes an operator cabin 118, which can be open or enclosed and may be accessed. Operator cabin 118 may include one or more control devices (not shown) such as, a joystick, a steering wheel, pedals, levers, buttons, switches, among other examples. The control devices are configured to enable the operator to control machine 100 and/or the bucket 112. Operator cabin 118 may also include an operator interface such as, a display device, a sound source, a light source, or a combination thereof.

Machine 100 can be used in a variety of industrial, construction, commercial or other applications. Machine 100 can be operated by an operator in operator cabin 118. The operator can, for example, drive machine 100 to and from various locations on a work site and can also pick up and deposit loads of material using bucket 112. By further way of example, both operation by a remotely located operator and autonomous or robotic operation are contemplated. Machine 100 can include a battery compartment connected to frame 102 and include a battery system 120. Battery system 120 is electrically coupled to the one or more electric motors of the work machine 100.

FIG. 2 is an illustration of a battery electric machine (BEM) 100 and a charger device 226. The charger device 226 provides charging energy to the BEM 100 using charging cable 232. The charger device 226 includes power converter circuitry (not shown) to produce the charge energy. The transfer of energy between the BEM 100 and the charger device 226 may be bi-directional and the battery system 120 of the BEM 100 may discharge energy to the charger device 226.

FIG. 3 is a block diagram of the BEM 100 and the charger device 226. The charger device 226 includes a charger controller 350 and the BEM 100 includes a charger interface controller (CIC) 352. A controller includes processing circuitry that includes one or more processors (e.g., microprocessors, digital signal processors (DSP), application specific integrated circuits (ASICs), a programmable gate arrays (PGAs), or equivalent discrete or integrated logic circuitry. A controller can include memory to store instructions performable by the processing circuitry. The instructions may be software or firmware instructions and the instructions configure the processing circuitry to perform the functions described for the specific controller. The CIC 352 interfaces with the battery system 120 of the BEM 100 and the charger device 226. The CIC 352 and the charger controller 350 perform a handshaking protocol to configure the interface for charging or discharging.

FIG. 4 is a flow diagram of an example of a method 400 of operating a bi-directional charging system for a BEM 100. The method 400 relates to charging the battery system 120 of the BEM 100 and may be performed using the charging system of FIG. 3. At block 405, the charge device 226 is disabled. When a charging session is to be started, at blocks 410 and 415, the CIC 352 performs a handshaking protocol with the charger device 226 to connect the charger device 226. The handshaking protocol may include the CIC 352 sending a request for charging of the BEM 100 to the charger controller 350. The request may include information regarding one or more of the power, voltage, and current requirements for charging the battery system 120 of the BEM 100. The charger controller 350 sends a charging confirmation message to the CIC 352 in response to the request. The CIC 352 brings the battery system 120 online for charging. The CIC 352 may then determine initialization status regarding the charger device 226 and the charging cable 232. The initialization status includes information regarding the connections state of the charging cable 232 and the health of the charger device 226.

The CIC 352 may perform a charging cable interlock process. At block 420, the CIC 352 locks one or more connectors of the charging cable 232, and at block 425, the CIC 352 performs a cable check to determine a connection status of the charging cable 232. The CIC 352 monitors the connections and disconnections of the connectors of the charging cable. The charging cable 232 includes control actuators to lock and unlock the cable connector. The CIC 352 controls the actuators to lock and unlock the charging cable connectors on all sides of the connectors for positive charging engagement and safe disconnection. The CIC 352 may record the cable connector mating cycles to determine connector life cycle and perform prognostic alerts based on the number of connector mating cycles.

The charging cable 232 may include multiple voltage sensors and current sensors. The CIC 352 monitors the voltage sensors, current sensors, connector connection voltages, and charging states to determine when to activate or deactivate the charging cable locks. The CIC 352 may monitor and command local voltages at the charge port to communicate with the charge device 226 so as to onboard (activate) a healthy charger device 226 and offboard (deactivate) a faulty charger device 226.

At block 430, at any time during the charging process, the CIC 352 monitors for a fault in the charging cable 232 or the charger device 226, or for a stop command received from a user or a fleet management system. In the event of a fault, a fault reset request is generated and a fault reset is performed at block 435.

At block 440, the charger controller 350 communicates the precharge status to the CIC 352 as part of the initialization status. The pre-charge status may include information that the charger device 226 has completed precharge and will meet the power, voltage, and current requirements for charging the battery system 120 of the BEM 100. The power converter circuitry of the charger device 226 may be configurable to adjust one or more of the power, voltage, and current output from the charger device 226.

At block 445, the CIC 352 sends a command to the charger controller 350 to close the contactors of the charging path to charge the battery system in response to the initialization status. The charger controller 350 closes the contactors and any other switches included in the charging path in response to the command from the CIC 352 and charging energy is delivered to the battery system 120 from the charger device 226. When charging is complete at block 450, the CIC 352 may send a command to the charger controller 350 to open the contactors and disable the charger device 226.

FIG. 5 is a flow diagram of another example of a method 500 of operating a charging system for a BEM 100. The method 500 relates to discharging energy from the battery system 120 of the BEM 100 into the charger device 226.

At block 505, the charge device 226 is disabled. To start the discharging session, at blocks 510 and 515, the CIC 352 performs a handshaking protocol with the charger device 226 to connect the charger device 226. The handshaking protocol includes the CIC 352 sending a request for discharging battery system 120 to the charger controller 350. At blocks 520 and 525 the CIC 352 performs checks with the charger device 226. At block 540, the CIC 352 waits for the charger device 226 to setup for negative current acceptance, such as by receiving a discharge confirmation message from the charger controller 350 for example. The CIC 352 calculates the discharge current and sets the maximum discharge current according to the charger device 226 connected to the charging cable 232.

At block 550, when the checks and calculations are complete and the discharge confirmation message is received, the CIC 352 sends a command to the charger controller 350 to close contactors of the discharge path of the charger device 226 and the CIC 352 closes contactors of the battery system 120 to discharge energy to the charger device 226. The charger device 226 includes power converter circuitry to regulate the discharge energy according to the maximum discharge current. When the discharging is complete at block 550, the CIC 352 sends a command to the charger controller 350 to open the contactors of the charger device 226 and the CIC 352 disables the charger device 226. At block 530, the CIC checks for a fault or a stop command at any point in the discharging process.

FIG. 6 is a diagram of another example of a bi-directional charging system 200 for a battery electric machine 100. The system 600 includes multiple charger devices 226. Each charger device 226 is configured to provide high- capacity charge energy for charging a BEM 100. Each of the charger devices 226 can be coupled to one or more switch devices 628 that connect the charger device 226 to a grid, a generator set device, etc. The charging system 600 also includes at least one charge dispenser device 630. Multiple charger devices 226 are connected to one charge dispenser device 630 to provide charging energy in parallel to the charge dispenser device 630. The example system of FIG. 6 includes two charge dispenser devices 630 and one to six charger devices 226 can be connected to each charge dispenser device 630 in the example.

The charge dispenser device 630 is connected to the BEM 100 by a charging cable 232 and cable connector. The charging cable 232 may be air-cooled or liquid-cooled depending on the capacity of the charging cable 232. A charge dispenser device 630 aggregates the charging energy from the charger devices 226 connected to it to provide the aggregated charging energy to the BEM 100 through the charging cable 232. This makes the charging system 600 modular and the charging energy produced from any of one to six chargers can be received in parallel and aggregated in the example system of FIG. 6. In some examples, more than six charger devices 226 can be connected to one charge dispenser device 630 and the charge from more than six charger devices can be aggregated by the charge dispenser device 630.

The BEMs 100 being charged may be automated and may operate without a human operator. Operation of the BEMs may be through a fleet management system 634. The fleet management system 634 may be implemented through one or more servers located at the remote site, or the one or more servers may be cloud-based. The fleet management system 634 manages the displacements of the automated BEMs 100 at the job site. The fleet management system 634 may communicate with the BEMs 100 and charge dispenser device 630 wirelessly (e.g., wireless WiFi). The fleet management system 634 sends specific instructions to the BEMs 100 to move them on specific lanes across the job site. When the fleet management system 634 determines that a BEM 100 needs charging, the fleet management system 634 may match a BEM 100 to a charge dispenser device 630 based on the charge dispenser’s location, availability, and capacity. Upon connection to the BEM 100, the charge dispenser device 630 or the CIC 352 of the BEM will automatically start a charging session. On completion, the charge dispenser device 630 may notify the fleet management system 634 that the BEM 100 can leave. All these operations can be executed without the help of a human operator on site.

The transfer of energy between the BEM 100 and the charge dispenser device 630 may be bi-directional and the battery system 120 of the BEM 100 may discharge energy to the charger device 226. Upon connection to the BEM 100, the charge dispenser device 630 or the CIC 352 of the BEM will automatically start a discharging session.

FIG. 7 is a block diagram of an example of portions of a charge dispenser device 630. The charge dispenser device 630 includes multiple charger input receptacles 740 to simultaneously receive electrical energy from multiple charger devices 226 in parallel. Each of the charger devices 226 can provide energy to charge a BEM 100. The charger devices 226 can include power converters to produce the charge energy. The charger devices 226 are connected to the charger input receptacles 740 by charger device cables 748. The charge dispenser device 630 may send commands to the charger devices 226 to set the output of the power converters to a voltage and current appropriate for the type of BEM 100 being charged. The charge dispenser device 630 includes a cable output connector 742 to connect to the charging cable 232 that is connectable to the battery system 120 of the BEM 100. The charge dispenser device 630 can include a dispenser bus 744 that provides accumulated charger energy to the cable output connector 742. In some examples, the charge dispenser device 630 includes more than one output connector 724. The multiple output connectors 742 may be used to send charging energy to multiple battery systems 120 of a BEM 100 or to the battery systems 120 of more than one BEM 100.

The charge dispenser device 630 also includes a dispenser controller 746 and the charger devices 226 each include a charger controller 350. The dispenser controller 746 includes a communication port 754 to communicate information with the charger controllers 350 of the charger devices 226. The dispenser controller 746 and the charger controllers 350 may communicate using a communication network such as an Ethernet network. The dispenser controller 746 may include another communication port 752 to communicate with the CIC 352. The communication port 752 and the CIC 352 may be connected through dedicated conductors of the charging cable 232. The dispenser controller 746 may include a wireless communication port (not shown) to communicate wirelessly with the fleet management system 634.

FIG. 8 is a diagram of an example of communication networks for the charger devices 226 and charge dispenser device 630 of a charging system 600. The dispenser controller 746 communicates with the charger controllers 350 using a 4-wire Ethernet network. The charger devices 226 and the charge dispenser device 630 may include interior sub-networks, such as a 2-wire Ethernet network (e.g., multi -drop network) and one or more controller area networks (CANs). The interior sub-networks are for communication among devices within the charger devices 226 and within the charge dispenser device 630.

Returning to FIG. 7, the dispenser controller 746 communicates with the CIC 352 of the BEM 100 to perform charging sessions and discharging sessions. Aggregating the output of multiple charger devices 226 provides higher capacity charging than approaches that use one charger device 226. The aggregating techniques described are modular and the number of chargers that can be brought onboard is flexible to allow charging of different types of BEMs 100. Discharging sessions allow the stored energy of the battery system 120 to be bled off. Typically, the charge dispenser device 630 will distribute the received discharging current equally among the onboard charger devices 226. Industrial Applicability

FIG. 9 is a flow diagram of an example of another method 900 of operating a bi-directional charging system for a BEM 100. The energy transfer between the charger devices 226 and the BEM 100 is bidirectional and the charge dispenser device 630 both charges the battery system 120 of the BEM 100 by aggregating charge energy of multiple charger devices 226 and distributes discharge energy from the battery system 120 to multiple charger devices 226.

At block 905, the multiple charger devices 226 connected to a charge dispenser device 630 are initially disabled by the dispenser controller 746 of the charge dispenser device 630. At block 910, the dispenser controller 746 and the CIC 352 of the BEM 100 automatically detect connection. The connection may be detected by the dispenser controller 746 through the connection of the charging cable 232 using communication port 752.

When connected, the dispenser controller 746 and the CIC 352 may perform either a charging session or a discharging session. For a charging session, the dispenser controller 746 and the CIC 352 may communicate using a handshaking protocol similar to the communication flow in the example of FIG. 4. For instance, at block 915 the charging session may begin with the CIC 352 sending a request for charging of the BEM 100 to the dispenser controller 746. The request can include charging requirements for the battery system 120 of the BEM 100. The charging requirements can include one or more of power, voltage, and current for the charging provided to the battery system 120 via the charging cable 232.

In response to the request, at block 920 the dispenser controller 746 uses the charging information to send one or more activation messages to the charger controllers 350 to activate or bring onboard multiple charger devices 226. The dispenser controller 746 may activate or bring onboard all the charger devices 226 for the charging session or activate a multiple number of chargers less than all the charger devices 226.

At block 925, the CIC 352 may wait to receive initialization status for the charging session. The initialization status may include a cable check by the CIC 352. Either of the CIC 352 and the dispenser controller 746 may perform the charging cable interlock process described previously herein. In the charging cable interlock process, the connections and disconnections of the connectors of the charging cable 232 are monitored. The actuators are activated and deactivated to lock and unlock the charging cable connectors on all sides of the connectors for positive charging engagement and safe disconnection. The cable connector mating cycles to determine connector life cycle and perform prognostic alerts. If there are multiple output connectors 742 on the charge dispenser device 630, the connector mating cycles for each output connector 742 may be monitored independently. The initialization status may include an indication from the dispenser controller 746 that pre-charge of the charger devices 226 is completed. In some examples, the dispenser controller 746 performs a cable check in addition to, or as an alternative, to the cable check by the CIC 352 and sends cable connection status to the CIC 352.

At block 930, in response to the initialization status indicating all checks are complete, the CIC 352 sends a command to the dispenser controller 746 to close contactors of the charger devices 226 and the CIC 352 closes contactors of the battery system 120. The charging energy is provided to the battery system from the activated charger devices 226 when the contactors and any other switches of the charging path are closed.

The charge dispenser device 630 receives the charging energy from the activated or onboard charger devices 226 and delivers the charging energy to the BEM 100 via the charging cable 232 during the charging session. The dispenser controller 746 may adjust the charging energy output of one or more of the activated charger devices 226 during the charging session to balance the load among the onboard charger devices 226. Balancing the load during a charging session may be useful to extend the operating life of the charger devices 226.

The CIC 352 and the dispenser controller 746 check for faults or a stop command during the charging. When the dispenser controller 746 detects a fault in one or more charger devices 226, the dispenser controller 746 may one or more deactivation and activation messages to deactivate the defective charger devices 226 and activate replacement charger devices 226. The dispenser controller 346 may detect a change (e.g., a decrease) in charge capability of one or more charger devices 226 and send one or more activation messages to change (e.g., increase) the number of active charger devices 226 in response to the detection.

At block 935, the CIC 352 and dispenser controller 746 wait for the charging of the battery system 120 to complete. When charging is completed, the CIC 352 may send a communication to the dispenser controller 746 that charging is complete or a communication that includes a command for the dispenser controller 746 to open the contactors and disable the charger devices 226. At block 940, the dispenser controller 746 opens the contactors and disables the charger devices 226 in response to the communication from the CIC 352.

The energy transfer between the charger devices 226 and the BEM 100 is bi-directional and the charge dispenser device 630 both charges the battery system 120 of the BEM 100 by aggregating charge energy of multiple charger devices 226 and distributes discharge energy from the battery system 120 to multiple charger devices 226.

For a discharging session, the dispenser controller 746 and the CIC 352 may communicate using a handshaking protocol similar to the communication flow in the example of FIG. 5. At block 945, a discharging session may begin with the CIC 352 sending a request for discharging the battery system 120 to the dispenser controller 746. In response to the discharging request, the dispenser controller 746 configures the charge dispenser device 630 and charger devices 226 for acceptance of the negative discharge current. The dispenser controller 746 determines the number of charger devices 226 to activate to receive the discharging energy and calculates the amount of discharge current that will be provided to each onboard charger device 226. The dispenser controller 746 calculates the combined discharge capability of the charger devices 226 to determine a value of the maximum discharge current for the discharging session.

At block 950, the dispenser controller 746 sends a discharging confirmation message to the CIC 352. The discharging confirmation message may include the value of the maximum discharge current for the discharging session. At block 955, the CIC 352 may wait to receive initialization status for the charging session, or the initialization status may be included with the discharging confirmation message. The initialization status may include a cable check by one or both of the CIC 352 and the dispenser control 746, and the status may include a cable check and the cable interlock process described previously herein. Either of the CIC 352 and the dispenser controller 746 may perform the charging cable interlock process. The connections and disconnections of the connectors of the charging cable 232 are monitored. The actuators are activated and deactivated to lock and unlock the charging cable connectors on all sides of the connectors for positive charging engagement and safe disconnection. The cable connector mating cycles are monitored to determine connector life cycle and perform prognostic alerts. If there are multiple output connectors 742 on the charge dispenser device 630, the connector mating cycles for each output connector 742 may be monitored independently. The dispenser controller 746 may also perform a pre-discharge initialization to prepare to close contactors and switches corresponding to a discharge path of the charge dispenser device 630 and charger devices 226.

At block 960, when system checks are complete, the CIC 352 sends a command to the dispenser controller 746 to close the contactors of the discharge path of the charge dispenser device 630 and the CIC 352 closes the contactors of the discharge path of the BEM 100. The dispenser controller 746 closes the contactors and any switches of discharge path of the charge dispenser device 630 and distributes received discharge current to the onboard charger devices 226. The charger devices 226 receive the discharge current when the contactors are closed. All the contactors in the charger devices 226 are switched closed except for AC contactors when the charger devices 226 are in the current sink mode. The charger devices 226 perform power electronics regulation to maintain and not exceed the maximum current bleed off to not damage the power electronics.

At block 965, the CIC 352 and dispenser controller 746 wait for the discharging of the battery system 120 to complete. When discharging is completed, the CIC 352 may send a communication to the dispenser controller 746 that discharging is complete or a communication that includes a command for the dispenser controller 746 to open the contactors and disable the charger devices 226. At block 970, the dispenser controller 746 opens the contactors and disables the charger devices 226 in response to the communication from the CIC 352.

The CIC 352 and the dispenser controller 746 check for faults or a stop command during the discharging session. When the dispenser controller 746 detects a fault in one or more charger devices 226, the dispenser controller 746 may deactivate the defective charger devices 226 and activate replacement charger devices 226.

The charging system is bi-directional and modular in that any number of charger devices 226 can be included in the charging session or the discharging session. The charging system is flexible for different types of BEMs. The charge dispenser device 630 configures the charger devices 226 according to the requirements of charging or discharging the BEM 100.

Unless explicitly excluded, the use of the singular to describe a component, structure, or operation does not exclude the use of plural such components, structures, or operations or their equivalents. The use of the terms “a” and “an” and “the” and “at least one” or the term “one or more,” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B” or one or more of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B; A, A and B; A, B and B), unless otherwise indicated herein or clearly contradicted by context. Similarly, as used herein, the word "or" refers to any possible permutation of a set of items. For example, the phrase "A, B, or C" refers to at least one of A, B, C, or any combination thereof, such as any of: A; B; C; A and B; A and C; B and C; A, B, and C; or multiple of any item such as A and A; B, B, and C; A, A, B, C, and C; etc. The above detailed description is intended to be illustrative, and not restrictive. The scope of the disclosure should, therefore, be determined with references to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

1. A bi-directional charging system for a battery electric machine (BEM), the charging system comprising: a battery system 120; at least one contactor connecting a charging cable receptacle of the BEM (100) and the battery system; and a charger interface controller (CIC) 352 operatively coupled to the battery system and configured to: send a request to another controller for charging the BEM; enable charging of the battery system via the charging cable receptacle in response to a charging confirmation message received from the other controller; send a request to the other controller for discharging the BEM; and enable discharging of the battery system via the charging cable receptacle in response to a discharging confirmation message received from the other controller.

2. The charging system of claim 1, wherein the CIC is configured to: perform a cable check to determine connection status of the charging cable (232) in response to receiving the charging confirmation message; and close the at least one contactor according to the connection status and the charging confirmation message.

3. The charging system of claim 1 or claim 2, wherein the CIC is configured to: perform a cable check to determine connection status of the charging cable in response to receiving the discharging confirmation message; and close the at least one contactor according to the connection status and the discharging confirmation message.

4. The charging system of any one of claims 1-3, wherein the CIC is configured to: send the request for charging to a charger controller (350) of a charger device (226) to provide charging energy to charge the battery system; receive an indication of pre-charge status from the charger controller; and send a command to the charger controller to close one or more contactors of the charger device.

5. The charging system of any one of claims 1-4, wherein the CIC is configured to: send the request for discharging to a charger controller of a charger device to receive discharging energy from the battery system; receive the discharging confirmation message from the charger controller; and send a command to the charger controller to close one or more contactors of the charger device.

6. The charging system of any one of claims 1-5, wherein the CIC is configured to: send the request for charging to a dispenser controller (746) of a charge dispenser (630) that aggregates charge energy from multiple charger devices, wherein the request for charging includes charging requirements for the BEM; and send a command to the dispenser controller to close contactors of the multiple charger devices in response to the charge confirmation message.

7. The charging system of any one of claims 1-6, wherein the CIC is configured to: send the request for discharging to a dispenser controller of a charge dispenser that aggregates charge energy from multiple charger devices, wherein the request for charging includes charging requirements for the BEM; receive the discharging confirmation message from the dispenser controller, wherein the discharging confirmation message includes a maximum discharge current for the BEM battery system; and send a command to the dispenser controller to close contactors of the multiple charger devices in response to the discharging confirmation message.

8. The charging system of any one of claims 1-7, wherein the CIC is configured to: perform a cable check to determine connection status of the charging cable in response to receiving the charging confirmation message; lock connectors of the charging cable according to the determined connection status; and unlock the connectors of the charging cable when charging is complete.

9. A method of operating a charging system for a battery electric machine (BEM), the method comprising: charging a battery system (120) of the BEM (100) using charge energy from at least one charger device (226) of the charging system; and discharging the battery system of the BEM by sending discharge energy from the battery system of the BEM to the at least one charger device, wherein the discharging includes the at least one charger device regulating the discharge energy according to a maximum discharge current.

10. The method of claim 9, wherein the charging the battery system includes: sending by a charger interface controller (CIC) (352) a request for charging of the BEM to a charger controller (350) of the at least one charger device; determining, by the CIC, initialization status regarding the at least one charger device and a charging cable (232) used to provide the charging energy from the at least one charger device; and sending a command from the CIC to the charger controller to close contactors of the charger device and the CIC closing contactors of the battery system to charge the battery system in response to the initialization status.

11. The method of claim 10, wherein the determining the initialization status includes: performing, by the CIC, a cable check to determine a connection status of the charging cable; and receiving from the at least one charger device, a pre-charge status of the at least one charger device.

12. The method of claim 10 or claim 11, including: automatically detecting, by the CIC, a connection of the charging cable to the at least one charger device; and performing, by the CIC, a charging cable interlock process in response to the detecting, the charging cable interlock process including activating actuators of the charging cable to lock cable connectors of all sides of the charging cable.

13. The method of any one of claims 9-12, wherein the discharging the battery system includes: sending by a charger interface controller (CIC) a request for discharging of the BEM to a charger controller of the at least one charger device; receiving, by the CIC, a discharge confirmation message of acceptance of discharge energy by the charger device; and sending a command from the CIC to the charger controller to close contactors of the charger device and the CIC closing contactors of the battery system to discharge the battery system in response to the receiving the discharge confirmation message.

14. The method of any one of claims 9-13, wherein the charging the battery system includes: aggregating charge energy produced by multiple charger devices using a charge dispenser (630) of the charging system; and charging the battery system using the aggregated charge energy; and wherein discharging the battery system includes: sending discharge energy from the battery system of the BEM to the charge dispenser; and distributing, by the charge dispenser, the discharge energy to the multiple charger devices.

15. The method of claim 14, wherein the charging the battery system includes: sending by a charger interface controller (CIC) a request for charging of the BEM to a dispenser controller (746) of the charge dispenser, wherein the request includes charging requirements for the BEM; activating a multiple number of charger devices included in a plurality of available charger devices according to the charging requirements; receiving, by the CIC, initialization status from the charge dispenser regarding the multiple charger devices and a charging cable used to provide the charging energy from the charge dispenser; and sending a command from the CIC to the charge dispenser to close contactors of the charger devices and the CIC closing contactors of the battery system to charge the battery system in response to the initialization status.