GB2624462A

GB2624462A - Energy storage charging system for a vehicle

Info

Publication number: GB2624462A
Application number: GB2217382.7A
Authority: GB
Inventors: Shiluveru Kharan; Sa Satyam; Keshari Shuvam
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2022-11-21
Filing date: 2022-11-21
Publication date: 2024-05-22
Also published as: WO2024110198A1; GB202217382D0

Abstract

An energy storage charging system 10 for a vehicle 1 includes: an alternating current (AC) charging interface 100; a direct current (DC) charging interface 102; an energy storage interface 104; an AC charging circuit 108 electrically connected to the AC interface and including a DC/DC voltage converter 112; and a branch switcher 124. In a first configuration, the branch switcher selectively couples the DC interface to an input of the DC/DC converter of the AC charging circuit to create a DC charging path from the DC interface to the energy storage interface. A first branch 114 connects the AC interface to the energy storage interface via the AC charging circuit. A second branch 116 connects the DC interface to the energy storage interface, by-passing the DC/DC converter when the branch switcher is in a second configuration. In the first configuration, a third branch 120 connects to the first branch, between an AC/DC converter 110 and the DC/DC converter. The branch switcher may comprise: a switch in each of the second and third branches (figure 4B); or a single switch having a first output connected to the second branch and a second output connected to the third branch (figure 4C).

Description

ENERGY STORAGE CHARGING SYSTEM FORA VEHICLE

TECHNICAL FIELD

The present disclosure relates to an energy storage charging system for a vehicle, a method of using the energy storage charging system, and computer software for implementing the method. In particular, but not exclusively it relates to an energy storage charging system with AC and DC charging circuits that can be interconnected by a branch.

BACKGROUND

A challenge facing the widespread adoption of Electric Vehicles (EVs) is the last mile connectivity issue. There is a chance that the user/rider may become stranded without EV charge and no EV charging stations nearby. A V2V (Vehicle to Vehicle) charging technique allows charge transfer between two EVs (donor vehicle and acceptor vehicle) off the electrical grid. It may be desirable to modify or adapt a vehicle onboard energy storage charging system to become V2V compatible.

SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide a vehicle, an energy storage charging system for the vehicle, a method of using the energy storage charging system, and computer software for implementing the method, as claimed in the appended claims.

According to an aspect of the invention there is provided an energy storage charging system for a vehicle, the energy storage charging system comprising: an alternating current (AC) charging interface; a direct current (DC) charging interface; an energy storage interface; an AC charging circuit electrically connected to the AC charging interface, wherein the AC charging circuit includes a DC-DC voltage converter; and a branch switcher configurable in a first configuration to selectively couple the DC charging interface to an input of the DC-DC voltage converter of the AC charging circuit to create a DC charging path from the DC charging interface to the energy storage interface.

An advantage of the branch switcher is that the charging system can be unidirectional (having a unidirectional DC-DC converter) and V2V charging compatible. This is because the vehicle's DC charging interface can be connected internally to the input of the DC-DC converter of the AC charging circuit, to V2V charging with current flowing in the normal direction manner through the DC-DC converter. Alternatively, when acting as a donor vehicle, the vehicle's DC charging interface may be connected directly to the energy storage interface, bypassing the DC-DC converter, so that electrical power is not required to flow backwards through the DC-DC converter.

In some examples, the AC charging circuit comprises a first branch configured to electrically connect the AC charging interface to the energy storage interface of the vehicle, wherein a second branch is configured to electrically connect the DC charging interface to the energy storage interface when the branch switcher is in a second configuration, and wherein a third branch is configured to electrically connect the second branch to the first branch when the branch switcher is in the first configuration.

In some examples, the third branch electrically connects to the first branch between an AC-DC voltage converter of the AC charging circuit and the DC-DC voltage converter of the AC charging circuit.

In some examples, the branch switcher comprises a first electrical switch in the second branch and a second electrical switch in the third branch. Alternatively, the branch switcher comprises a single electrical switch having a first output electrically connected to the second branch and a second output electrically connected to the third branch. The branch switcher may be an electromechanical branch switcher or a semiconductor branch switcher.

In some examples, the second branch is configured to electrically connect the DC charging interface to the energy storage interface to provide a substantially constant-voltage transmission path between the DC charging interface and an electrical energy storage means.

In some examples, the second branch is configured to electrically connect the DC charging interface directly to the energy storage interface to provide the substantially constant-voltage transmission path.

In some examples, the DC-DC voltage converter of the AC charging circuit is a unidirectional DC-DC voltage converter. An advantage is obviating the need for complex or coordinated control of semiconductor switches within the DC-DC voltage converter.

In some examples, the energy storage charging system comprises an inrush current limiter between the branch switcher and the DC-DC voltage converter. An advantage is improved durability.

In some examples, energy storage charging system comprises a control system, the control system comprising one or more controllers, the control system configured to: receive a signal indicative of whether the vehicle charging system is to be operated in an acceptor mode or a donor mode, wherein the acceptor mode is for accepting DC electrical power via the DC charging interface from a second vehicle, and wherein the donor mode is for donating electrical power via the DC charging interface to the second vehicle; and control the branch switcher in dependence on the signal.

In some examples, controlling the branch switcher in dependence on the signal comprises: controlling the branch switcher to engage the second branch, in dependence on the signal indicating that the vehicle charging system is to be operated in the donor mode; and controlling the branch switcher to engage the third branch, in dependence on the signal indicating that the vehicle charging system is to be operated in the acceptor mode.

In some examples, the signal is indicative of which one of the donor mode and the acceptor mode has been user-selected via a human-machine interface.

In some examples, the control of the branch switcher is dependent on a user-specified limit of how much state of charge can be donated and/or accepted. In some examples, the control of the branch switcher is dependent on a state of charge difference between the vehicle and the second vehicle.

In some examples, the control system is configured to determine, through arbitration via communication with a control system of the second vehicle, a rate of power transfer in a selected one of the donor mode and the acceptor mode.

According to another aspect of the invention there is provided a vehicle comprising the energy storage charging system of any preceding claim.

According to a further aspect of the invention there is provided a method of controlling an energy storage charging system for a vehicle, the method comprising: controlling a branch switcher to a first configuration to selectively couple a DC charging interface of the vehicle to an input of a DC-DC voltage converter of an AC charging circuit of the vehicle, wherein the AC charging circuit is electrically connected to an AC charging interface of the vehicle, wherein the branch switcher in the first configuration creates a DC charging path from the DC charging interface to an energy storage interface of the vehicle.

According to a further aspect of the invention there is provided computer software that, when executed, is arranged to perform any one or more of the methods described herein. According to a further aspect of the invention there is provided a non-transitory computer readable medium comprising computer readable instructions that, when executed by one or more electronic processors, causes the one or more electronic processors to carry out any one or more of the methods described herein.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination that falls within the scope of the appended claims. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination that falls within the scope of the appended claims, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIG. 1 illustrates an example of a vehicle; FIG. 2 illustrates an example of a control system; FIG. 3 illustrates an example of a non-transitory computer-readable storage medium; FIG. 4A illustrates an example of a previous energy storage charging system; FIG. 4B illustrates a first example implementation of a new energy storage charging system; FIG. 4C illustrates a second example implementation of the new energy storage charging system; FIG. 5A illustrates an example vehicle-to-vehicle charging system during pre-charging; FIG. 5B illustrates the vehicle-to-vehicle charging system during charging; FIG. 6 is a flowchart illustrating an example of a method that relates to the implementation of V2V charging.

DETAILED DESCRIPTION

FIG. 1 illustrates an example of a vehicle 1 in which embodiments of the invention can be implemented. In some, but not necessarily all examples, the vehicle 1 is a passenger vehicle, also referred to as a passenger car or as an automobile. In other examples, embodiments of the invention can be implemented for other applications, such as commercial vehicles.

FIG. 2 illustrates an example control system 200 configured to implement one or more aspects of the invention. The control system 200 of FIG. 2 comprises a controller 201. In other examples, the control system 200 may comprise a plurality of controllers on-board and/or off-board the vehicle 1.

The controller 201 of FIG. 2 includes at least one processor 204; and at least one memory device 206 electrically coupled to the electronic processor 204 and having instructions (e.g. a computer program 208) stored therein, the at least one memory device 206 and the instructions configured to, with the at least one processor 204, cause any one or more of the methods described herein to be performed. The controller 201 may have an interface 202 comprising an electrical input/output I/O 210, 212, or an electrical input 210, or an electrical output 212, for receiving information and interacting with external components.

FIG. 3 illustrates a non-transitory computer-readable storage medium 300 comprising the instructions (cornputer software).

FIG. 4A illustrates a previous design of an energy storage charging system 10 (system') for an electrical energy storage means of the vehicle 1. The electrical energy storage means can comprise a traction battery 106 (battery). The battery 106 may comprise rechargeable electrical cells such as lithium ion cells or solid state cells, and may alternatively or additionally comprise capacitors or supercapacitors. The vehicle 1 can be an electric vehicle in the form of a hybrid electric vehicle (HEV), or a full (battery) electric vehicle (BEV). A HEV incorporates a second torque source such as an internal combustion engine. By contrast, a BEV is only capable of electrical propulsion.

The battery 106 of the vehicle 1 at full charge can provide a nominal electrical power in the order of at least tens of kilowatts, to enable electric-only driving or at least the provision of assistive tractive torque. An electric machine for driving the vehicle is not shown. A nominal voltage of the battery 106 can be in the order of hundreds of volts, in an example.

The system 10 illustrated in FIG. 4A and the other figures is configured for both alternating current (AC) charging and direct current (DC) charging of the battery 106.

The system 10 comprises an AC charging interface 100 and a separate DC charging interface 102. The AC charging interface 100 comprises a charging socket for an AC charging plug.

The DC charging interface 102 comprises a charging socket for a DC charging plug. The designs of said plugs and sockets are generally governed by international standards.

In some examples, one or both of the AC and DC charging interfaces 100, 102 can comprise a different type of interface such as an inductive coil for wireless inductive charging.

The AC charging interface 100 is electrically connected to an energy storage interface 104, such as a battery pack terminal, by an AC charging circuit 108.

The AC charging circuit 108 comprises a first electrically conductive branch (first branch') 114 electrically connecting the AC charging interface 100 to the energy storage interface 104. The AC charging circuit 108 comprises an AC-DC voltage converter 110 and a DC-DC voltage converter 112 in series along the first branch 114.

The AC-DC converter 110 is configured to convert AC power from the AC charging interface 100 to DC power on the battery side for charging the battery 106. The AC-DC converter 110 can comprise any appropriate rectifier circuitry. The AC-DC converter 110 can comprise a power factor correction (PFC) stage.

The DC-DC converter 112 is configured to control the voltage at the battery side (output side), and has an output voltage magnitude that can be greater than or less than the input voltage magnitude to the DC-DC converter.

The input of the DC-DC converter 112 is electrically connected in series to the output of the AC-DC converter 110. The DC-DC converter 112 is therefore to the battery side of the first branch 114 whereas the AC-DC converter 110 is to the AC charging interface side of the first branch 114.

The first branch 114 can comprise a first contactor (electrical switch) Cl between the AC charging interface 100 and the energy storage interface 104 for the battery 106, to electrically isolate the battery 106 from the AC charging interface 100. The first contactor Cl can be located between the DC-DC converter 112 and the energy storage interface 104, as shown, or can be located elsewhere.

In FIG. 4A, the DC charging interface 102 is electrically connected to the energy storage interface 104 for the battery 106 by a separate DC charging circuit 109. The DC charging circuit 109 comprises a second electrically conductive branch ('second branch') 116 electrically connecting the DC charging interface 102 to the energy storage interface 104. The DC charging interface 102 receives suitable DC power for charging. Wien the vehicle 1 is plugged into a charging station, the DC power has already been converted to DC offboard the vehicle 1.

The second branch 116 electrically connects the DC charging interface 102 to the energy storage interface 104 for the battery 106, without passing through the AC-DC converter 110 and without passing through the DC-DC converter 112.

The second branch 116 can comprise a second contactor (electrical switch) C2 between the DC charging interface 102 and the energy storage interface 104 for the battery 106, to electrically isolate the battery 106 from the DC charging interface 102. Wien the second contactor C2 is closed, the electrical connection between the DC charging interface 102 and the battery 106 may be direct. The connection/path is direct at least in the sense that the voltage at the energy storage interface 104 is substantially the same as the voltage at the DC charging interface 102, i.e., there is no onboard voltage conversion.

Vehicle-to-vehicle (V2V) charging schemes have been developed to enable vehicles to act as chargers, such as to rescue a stranded electric vehicle. In previous schemes, the AC-DC and DC-DC converters 110, 112 of the donor vehicle (the vehicle donating electrical power) have been of bidirectional design. A bidirectional DC-DC converter 112 enables electrical power flow in opposite directions and therefore enables the system 10 to act as a charger for the acceptor vehicle (e.g., the stranded vehicle).

A bidirectional converter differs from a unidirectional converter in several ways. For example, converting a unidirectional DC-DC converter 112 of PSFB (phase shift full bridge) design to a bidirectional circuit would involve swapping diodes for semiconductor switches. The semiconductor switches would be connected to gate driver circuitry. The gate driver circuitry would be connected to a phase shift controller. Sophisticated control schemes are required to ensure robust control when the battery 106 is supplying power (reverse power flow direction).

Previous implementations would cause the bidirectional DC-DC converters 112 of each vehicle to be electrically connected in series. Some implementations involve four modules in series: DC-DC, DC-AC, AC-DC, DC-DC. Some implementations involve an external offboard DC-DC converter. In this condition, stable control of power transfer would require the controllers of each bidirectional converter to communicate continuously to decide/negotiate each operating point.

The complexity involved makes V2V (vehicle-to-vehicle) charging challenging to implement.

Aspects and examples of the present invention provide new circuit topologies to enable V2V charging via the use of a single unidirectional DC-DC converter at the acceptor vehicle end, thereby avoiding the control complexity associated with serially interconnected bidirectional converters. As shown in the following figures and described below, the new circuit topologies involve a branch switcher.

FIG. 4B illustrates a first example of the new circuit topology of the system 10. The circuit topology is the same as FIG. 4A except for the stated differences. The difference is that a branch switcher is provided to selectively electrically couple the first branch 114 and the second branch 116. The branch switcher of FIG. 4B comprises a pair of contactors C2, C3 and a third electrically conductive branch ('third branch') 120 electrically interconnecting the second branch 116 and the first branch 114. The second contactor C2 is within the second branch 116 and the third contactor C3 is within the third branch 120.

The third branch 120 is electrically connected at one end to a node of the second branch 116 and at the other end to a node of the first branch 114. The node of the first branch 114 is between the output of the AC-DC converter 110 and the input of the DC-DC converter 112. The node of the second branch 116 is between the DC charging interface 102 and the second contactor C2.

FIG. 5B demonstrates the circuit of FIG. 4B in use for V2V charging. A charging cable 200 is connected to the DC charging interfaces 102 of the donor and acceptor vehicles 1A, 1B. The acceptor vehicle 1B has the circuit of FIG. 4B (or alternatively FIG. 4C explained later). The donor vehicle 1A can have the circuit of any of FIGS. 4A to 4C.

In order for the battery 106 of the donor vehicle 1A to charge the battery 106 of the acceptor vehicle 18, the second contactor C2 of the donor vehicle 1A is closed to permit electrical power flow therethrough. The second contactor C2 of the acceptor vehicle 1B is open to inhibit/prevent electrical power flow therethrough, and the first and third contactors Cl, C3 of the acceptor vehicle 1B are closed to permit electrical power flow therethrough. This is a first configuration of the branch switcher (C2, C3).

The contactors C1-C3 of the acceptor vehicle 1B in their above-described states ensure that the DC charging power received at the DC charging interface 102 of the acceptor vehicle 1B is directed through the third branch 120 to the first branch 114 and through the DC-DC converter 112 of the acceptor vehicle 1B. The DC-DC converter 112 outputs a controlled voltage for charging the battery 106 of the acceptor vehicle 1B. The first contactor Cl of the acceptor vehicle 1B would also be closed, so that the output from the DC-DC converter 112 reaches the energy storage interface 106.

The DC-DC converter 112 of the donor vehicle 1A is bypassed. The contactors Cl and C3 of the donor vehicle may be open. Therefore, only the DC-DC converter 112 of the acceptor vehicle 1B is used. Both DC-DC converters 112 (and AC-DC converters 110) can therefore be unidirectional in design, only permitting power transfer to their respective batteries 106 and not away from their respective batteries 106. Unidirectional DC-DC converters 112 obviate the need for complex or coordinated control of semiconductor switches, associated with bidirectional converters.

In an infrastructure DC charging situation in which a DC charging power for the acceptor vehicle 1B comes from a suitable charging station, there is no need to utilise the DC-DC converter 112 of the acceptor vehicle 1B. Therefore, the second contactor 02 of the acceptor vehicle 1B can be closed and the third contactor C3 of the acceptor vehicle 1B can be open. This is the second configuration of the branch switcher (C2, C3).

The contactors Cl, 02, C3 can be electromechanical or semiconductor-based, depending on the implementation. They may be automatically controlled, that is without user intervention.

FIG. 4C illustrates a second example circuit topology that provides equivalent functionality to that shown in FIG. 4B.

The difference of the second circuit topology of FIG. 4C is that the separate contactors C2, C3 are replaced with a single electrical switch 124 having an input electrically connected to the DC charging interface 102, a first output electrically connected to the second branch 116, and a second output electrically connected to the third branch 120. The branch switcher now comprises the third branch 120 and the single electrical switch 124.

The single electrical switch 124 can be a single pole dual throw (SPDT) switch, for example. The single electrical switch 124 can be electromechanical or semiconductor-based, depending on the implementation. It may be automatically controlled, that is without user intervention.

For V2V charging, the single electrical switch 124 of FIG. 40 may be controlled to connect its input to its second output electrically connected to the third branch 120, to bring the DC-DC converter 112 into the circuit. For infrastructure DC charging via a regular charging station, the single electrical switch 124 may be controlled to connect its input to its first output electrically connected to the second branch 116, to bypass the DC-DC converter 112 and connect directly to the energy storage interface 104.

FIGS. 5A-5B further illustrate additional circuit components/detail not shown in FIGS. 4A-4C.

These are described below.

Firstly, FIGS. 5A-5B illustrate the AC charging circuit 108 comprising a pair of parallel DC electrical lines DC+ and DC-connecting the AC-DC converter 110 to the energy storage interface 104.

Secondly, FIGS. 5A-5B illustrate the DC charging circuit 109 comprising a corresponding pair of parallel DC electrical lines DC+ and DC-, connecting the DC charging interface 102 to the energy storage interface 104.

The third branch 120 can connect the DC+ lines of the AC and DC charging circuits 108, 109 to each other, and simultaneously connect the DC-lines of the AC and DC charging circuits 108, 109 to each other. As shown, each contactor C1-C3 acts on both of the electrical lines DC+ and DC-.

Thirdly, FIGS. 5A-5B illustrate an inrush current limiter along the third branch 120, to reduce the maximum instantaneous electrical current drawn when charging is initiated. The inrush current limiter is in the form of an inrush-limiting electrical resistor 128. As shown, the inrush-limiting electrical resistor 128 can be connected or connectable to a DC+ line of the third branch 120. Alternatively, the inrush-limiting electrical resistor 128 can be connected or connectable elsewhere.

As shown in FIGS. 5A-5B, the third branch 120 can split into two parallel sub-branches, one comprising the inrush-limiting electrical resistor 128 and the other sub-branch comprising a contactor (electrical switch) C4.

FIG. 5A illustrates a pre-charging condition in which the contactor C4 is open so that all electrical current passes through the inrush-limiting electrical resistor 128. This limits inrush current whilst enabling the voltages on either side of the contactor C4 to be substantially equalised prior to closing contactor C4.

FIG. 5B illustrates charging in a steady state charging condition, wherein the contactor C4 is closed so that most or all charging current passes through the lower-resistance sub-branch comprising the contactor C4. The contactor C4 may only be open (FIG. 5A) for the order of milliseconds before being closed automatically (FIG. 5B), to minimise resistive losses during charging.

FIG. 6 is a flowchart illustrating an example of a method 600. The method 600 may be implemented by the above-described control system 200 of the vehicle 1, i.e., a computer-implemented method. The blocks may be performed in any order unless stated otherwise.

Some blocks may be omitted unless stated to be essential.

The method 600 relates to the implementation of V2V charging using any of the new circuit topologies described above.

Block 602 of the method 600 comprises determining that an electrical connection has been made to the DC charging interface 102 of the vehicle 1. For example, a charging cable 200 may be plugged into the DC charging interface 102. This determination can be made via existing vehicle onboard communication protocols.

Block 604 of the method 600 comprises determining a charging mode of the vehicle 1. The charging mode may be one of a plurality of charging modes. The charging modes may include V2V charging modes. The V2V charging modes may comprise a donor mode. The V2V charging modes may comprise an acceptor mode (requires circuitry as shown in FIG. 4B or 4C). If neither of these modes is selected, the vehicle 1 may be set up for charging by a charging station, by default. That is, the vehicle operates by default in the donor mode when connected to a charging station to receive controlled charge whether via the AC or DC charging interfaces 100, 102.

The donor mode causes the vehicle 1 to be operated as a donor vehicle 1A as defined earlier for V2V charging, to donate (provide) DC electrical power from the battery 106 for charging a battery 106 of a second (acceptor) vehicle. With reference to the existing circuit of FIG. 4A, this means that the second contactor 02 of the acceptor vehicle is closed. C1 Of present) may be open. With reference the circuit of FIG. 4B, C2 of the donor vehicle is closed, and Cl and C3 are open are open. Or, with reference to the circuit of FIG. 4C, the first output of the single electrical switch 124 of FIG. 4C is selected to directly connect the energy storage interface 104 to the DC charging interface 102, via the second branch 116.

The acceptor mode causes the vehicle 1 to be operated as a V2V acceptor vehicle 1B as defined earlier for V2V charging, to accept (receive) DC electrical power from a second (donor) vehicle 1, which may or may not be a vehicle according to the present invention. This mode is not available when the vehicle 1 has the circuit of FIG. 4A. With reference to the circuit of FIG. 48, this means that C2 is open and 03 is closed, to connect the DC charging interface 102 to the DC-DC converter 112 via the third branch 120. Or, with reference to the circuit of FIG. 4C, this means that the second output of the single electrical switch 124 is selected, to direct power through the third branch 120 to the DC-DC converter 112. Cl (if present) is closed.

When the vehicle 1 is DC-charged by a charging station rather than a donor vehicle 1A, C2 is closed to directly connect the DC charging interface 102 to the energy storage interface 104 via the second branch 116. Cl and C3 Of present) may be open. Or, with reference to the circuit of FIG. 40, this means that the first output of the single electrical switch 124 is selected.

Cl Of present) may be open.

The mode selection can be made automatically or manually. The control system 200 may receive a signal indicative of which one of the charging modes the system 10 is to be operated in, and control the branch switcher in dependence thereon.

If the mode selection is manual, the signal may be from a human-machine interface (HMI) 214. The signal may be indicative of which one of the modes has been selected via the HMI 214. The HMI 214 may be part of the vehicle 1 or a user's own mobile equipment (e.g., smartphone or the like) operably connected to the control system 200.

A manual selection ensures that user consent/control is given before V2V DC charging can commence. In some examples, a user may specify an amount or limit of how much state of charge can be donated and/or accepted. The control system 200 will ensure that V2V charging only occurs up to the specified amount or limit, before terminating V2V charging.

In another implementation, the control system outputs (e.g., causes display of) a prompt via an HMI 214, requesting the user to manually confirm which charging mode is to be used. The prompt may be initiated in dependence on detection of the connection as described in block 30 602.

In a further implementation, the mode selection is automatic via V2V communication between the donor and acceptor vehicles 1A, 1B such as through the charging cable 200. An automatic mode selection can be dependent on a state of charge difference between the vehicles 1A, 1B, to cause the vehicle having more charge to donate charge to the vehicle with less charge.

Block 606 of the method 600 comprises determining whether communication with the second vehicle 1 (donor or acceptor) has been established. In examples, this can comprise detecting whether the charging cable 200 is connected to both the donor vehicle 1A and the acceptor vehicle 1B.

If communication with the second vehicle has not been established, the method 600 may loop back to 604 or 602, and/or V2V DC charging may be disabled. If communication with the second vehicle has been established, the method 600 may proceed.

Block 608 comprises determining, through arbitration via communication with a control system 200 of the second vehicle 1, a rate of power transfer in a selected one of the donor mode and the acceptor mode. Circuitry to monitor and control voltage, current and power transfer are not illustrated or described herein as they are known by persons skilled in the art.

For example, the donor vehicle 1A may indicate a value(s) of how much voltage, current and/or electrical power for charging is available or permitted from the donor vehicle 1A. The acceptor vehicle 1B may reply with an acceptance of the indicated value(s) or requesting a modified (lower) version of the indicated value(s).

Block 610 of the method 600 comprises commencing V2V charging, assuming that a V2V charging mode has been selected. As described earlier in relation to FIGS. 5A-5B, an inrush current limiting strategy can be employed first.

It is to be understood that the or each controller 200 can comprise a control unit or computational device having one or more electronic processors (e.g., a microprocessor, a microcontroller, an application specific integrated circuit (ASIC), etc.), and may comprise a single control unit or computational device, or alternatively different functions of the or each controller 200 may be embodied in, or hosted in, different control units or computational devices. As used herein, the term "controller," "control unit," or "computational device" will be understood to include a single controller, control unit, or computational device, and a plurality of controllers, control units, or computational devices collectively operating to provide the required control functionality. A set of instructions could be provided which, when executed, cause the controller 200 to implement the control techniques described herein (including some or all of the functionality required for the method 600 described herein). The set of instructions could be embedded in said one or more electronic processors of the controller 200; or alternatively, the set of instructions could be provided as software to be executed in the controller 200. A first controller or control unit may be implemented in software run on one or more processors. One or more other controllers or control units may be implemented in software run on one or more processors, optionally the same one or more processors as the first controller or control unit. Other arrangements are also useful.

In the example illustrated in Figure 2, the or each controller 200 comprises at least one electronic processor 204 having one or more electrical input(s) 210 for receiving the signal as described earlier, and one or more electrical output(s) 212 for outputting one or more output signals to the system 10 to control the branch switcher in the manner described herein. The or each controller 200 further comprises at least one memory device 206 electrically coupled to the at least one electronic processor 204 and having instructions 208 stored therein. The at least one electronic processor 204 is configured to access the at least one memory device 206 and execute the instructions 208 thereon so as to perform processing steps such as determining the charging mode.

The, or each, electronic processor 204 may comprise any suitable electronic processor (e.g., a microprocessor, a microcontroller, an ASIC, etc.) that is configured to execute electronic instructions. The, or each, electronic memory device 206 may comprise any suitable memory device and may store a variety of data, information, threshold value(s), lookup tables or other data structures, and/or instructions therein or thereon. In an embodiment, the memory device 206 has information and instructions for software, firmware, programs, algorithms, scripts, applications, etc. stored therein or thereon that may govern all or part of the methodology described herein. The processor, or each, electronic processor 204 may access the memory device 206 and execute and/or use that or those instructions and information to carry out or perform some or all of the functionality and methodology describe herein.

The at least one memory device 206 may comprise a computer-readable storage medium (e.g. a non-transitory or non-transient storage medium) that may comprise any mechanism for storing information in a form readable by a machine or electronic processors/computational devices, including, without limitation: a magnetic storage medium (e.g. floppy diskette); optical storage medium (e.g. CD-ROM); magneto optical storage medium; read only memory (ROM); random access memory (RAM); erasable programmable memory (e.g. EPROM ad EEPROM); flash memory; or electrical or other types of medium for storing such information/instructions.

Example controllers 200 have been described comprising at least one electronic processor 204 configured to execute electronic instructions stored within at least one memory device 206, which when executed causes the electronic processor(s) 204 to carry out the method as hereinbefore described. However, it will be appreciated that embodiments of the present invention can be realised in any suitable form of hardware, software or a combination of hardware and software. For example, it is contemplated that the present invention is not limited to being implemented by way of programmable processing devices, and that at least some of, and in some embodiments all of, the functionality and or method steps of the present invention may equally be implemented by way of non-programmable hardware, such as by way of non-programmable ASIC, Boolean logic circuitry, etc. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

The blocks illustrated in FIG. 6. may represent steps in a method and/or sections of code in the computer program 208. The illustration of a particular order to the blocks does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the block may be varied. Furthermore, it may be possible for some steps to be omitted.

Although embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as claimed.

Features described in the preceding description may be used in combinations other than the combinations explicitly described.

Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

CLAIMS1. An energy storage charging system for a vehicle, the energy storage charging system comprising: an alternating current (AC) charging interface; a direct current (DC) charging interface; an energy storage interface; an AC charging circuit electrically connected to the AC charging interface, wherein the AC charging circuit includes a DC-DC voltage converter; and a branch switcher configurable in a first configuration to selectively couple the DC charging interface to an input of the DC-DC voltage converter of the AC charging circuit to create a DC charging path from the DC charging interface to the energy storage interface.
2. The energy storage charging system of claim 1further comprising a first branch configured to electrically connect the AC charging circuit to the energy storage interface of the vehicle, and a second branch configured to electrically connect the DC charging interface to the energy storage interface by-passing the DC-DC voltage converter when the branch switcher is in a second configuration, wherein a third branch is configured to electrically connect the second branch to the first branch when the branch switcher is in the first configuration
3. The energy storage charging system of claim 2, wherein the third branch electrically connects to the first branch between an AC-DC voltage converter of the AC charging circuit and the DC-DC voltage converter of the AC charging circuit.
4. The energy storage charging system of claim 2 or 3, wherein the branch switcher comprises a first electrical switch in the second branch and a second electrical switch in the third branch.
5. The energy storage charging system of claim 2 or 3, wherein the branch switcher comprises a single electrical switch having a first output electrically connected to the second branch and a second output electrically connected to the third branch.
6. The energy storage charging system of any one of claims 2 to 5, wherein the second branch is configured to electrically connect the DC charging interface to the energy storage interface to provide a substantially constant-voltage transmission path between the DC charging interface and an electrical energy storage means.
7. The energy storage charging system of any preceding claim, wherein the DC-DC voltage converter of the AC charging circuit is a unidirectional DC-DC voltage converter.
8. The energy storage charging system of any preceding claim, comprising an inrush current limiter between the branch switcher and the DC-DC voltage converter.
9. The energy storage charging system of any preceding claim, comprising a control system, the control system comprising one or more controllers, the control system configured to: receive a signal indicative of whether the vehicle charging system is to be operated in an acceptor mode, wherein the acceptor mode is for accepting DC electrical power via the DC charging interface from a second vehicle; and control the branch switcher in dependence on the signal.
10. The energy storage charging system of claim 9, when dependent on claim 2, wherein controlling the branch switcher in dependence on the signal comprises: controlling the branch switcher to engage the second branch, in dependence on the signal indicating that the vehicle charging system is not to be operated in the acceptor mode; and controlling the branch switcher to engage the third branch, in dependence on the signal indicating that the vehicle charging system is to be operated in the acceptor mode.
11. The energy storage charging system of claim 9 or 10, wherein the signal is indicative that the acceptor mode has been user-selected via a human-machine interface 30
12. The energy storage charging system of claim 9, 10, or 11, wherein the signal indicative of whether the vehicle charging system is to be operated in an acceptor mode may alternatively indicate that the vehicle charging system is to be operated in a donor mode, wherein the donor mode is for donating electrical power via the DC charging interface to the second vehicle, and wherein the control system is configured to determine, through arbitration via communication with a control system of the second vehicle, a rate of power transfer in a selected one of the donor mode and the acceptor mode.
13. A vehicle comprising the energy storage charging system of any preceding claim. 5
14. A method of controlling an energy storage charging system for a vehicle, the method comprising: controlling a branch switcher to a first configuration to selectively couple a DC charging interface of the vehicle to an input of a DC-DC voltage converter of an AC charging circuit of the vehicle, wherein the AC charging circuit is electrically connected to an AC charging interface of the vehicle, wherein the branch switcher in the first configuration creates a DC charging path from the DC charging interface to an energy storage interface of the vehicle.
15. Computer software that, when executed, is arranged to perform a method according to claim 14.