Battery integrated electric vehicle charger

Abstract

A battery integrated electric vehicle charger (BIEVC) 100 provides a scalable architecture for battery integrated / buffered charging of an electric vehicle (EV), and comprises: a plurality of charger u

Description

Field of the Invention The present invention relates to an EV charging system, and more particularly, although not exclusively, to a battery-integrated EV charger. Background Electric vehicle (EV) chargers charge EVs by supplying them with electrical power from a power grid. Recently, a new type of EV charging systems has emerged: battery-integrated EV chargers (BIEVC). BIEVCs integrate energy storage systems, such as large-scale batteries, into conventional EV charging architecture. BIEVCs can store electricity, such as excess electricity, or electricity obtained from the grid during off-peak hours at a reduced cost, and release it during EV charging e.g. in addition to or instead of electricity from the grid. For this reason, BIEVCs are sometimes referred to as battery-buffered EV chargers (BBEVCs). Integrating batteries into EV charging systems in this way can increase the overall charging capacity of the system, enable faster, more reliable and / or cheaper EV charging, as well as improve grid stability with minimal infrastructure upgrades. Some BIEVCs can also exchange electricity with the grid bi-directionally and can be used to return stored electricity back to the grid, thereby stabilising it. Typically, electricity from the grid is supplied in the form of alternating current (AC), while EV batteries require a direct current (DC) in order to be charged. For this reason, conventional EV charging systems including BIEVCs comprise AC / DC converters (uni- or bi-directional respectively) to enable exchange of electricity with the grid and the EVs. There is a need for improved BIEVCs, which are cheaper and more scalable, have improved, more granular controllability, and do not require upgrades to existing local grid infrastructure. The present invention has been devised in light of the above considerations. Summary of the Invention In a first aspect, there is provided a battery integrated electric vehicle charger, BIEVC, for charging an electric vehicle, the BIEVC comprising: a plurality of charger units electrically connected to one another in parallel, each charger unit comprising: a plurality of sub-units each comprising a battery module and a local controller electrically connected thereto, wherein the local controllers of the plurality of sub-units are electrically connected to one another in series to form a modular multilevel converter, MMC; the BIEVC further comprising: a master controller communicatively coupled to the plurality of local controllers to control an output of one or more of the sub-units; and a master power distribution unit, PDU, electrically connectable to a power grid, and to an electric vehicle for charging, wherein the master PDU is further electrically connectable to the plurality of charger units. Using MMC architecture in combination with the battery modules in each charger unit ensures granular controllability of the overall output of the charger unit. This is because each battery module is electrically connected to its respective local controller and thus the output from the battery module is fed into its local controller where it can be adjusted / modulated to control the overall output of the respective sub-unit. For example, each local controller can control the voltage output of its respective sub-unit by performing voltage control on the output of the respective battery module. Due to the series connection between the local controllers, the overall voltage output from each charger unit is the sum of the voltage outputs from the plurality of sub-units. As such, individual control of the voltage output from the sub-units can achieve accurate and precise control of the voltage and / or waveform (e.g. AC, DC, or arbitrary) of the overall output from the respective charger unit. Furthermore, the present BIEVC provides a scalable architecture for battery integrated / buffered charging. Specifically, by electrically connecting the charger units in parallel to one another, it can be ensured that the output current from the BIEVC (e.g. DC for EV charging) can be easily scaled up or down respectively with the addition or removal of charger units. Each battery module comprises a plurality of battery cells. The charger units can act as energy storage and buffering units for the BIEVC. Each battery module may be in direct physical contact with its local controller. Alternatively, each battery module may be spaced from its local controller. Optionally, each local controller may be a printed circuit board (PCB). The / each local controller may be a commercially available STM32 controller, such as an STM32F0 controller. Optionally, each local controller may comprise a local communication unit communicatively coupled to the master controller. Each local controller / communication unit may be communicatively coupled to the master controller directly or indirectly, e.g. via a local power distribution unit PDU, or an intermediate controller of the local PDU, as described in more detail below. Direct / indirect communicative coupling may be achieved for example via a bus and / or a data transfer cable such as a fibre optics cable. Each local controller may receive power control instructions and / or cell information from the master controller, for example via the respective local communication unit. The cell information may comprise information about neighbouring battery modules such as voltage and / or temperature of the respective battery module(s), and / or current through the local controller(s), and / or temperature of the local controller(s) and / or state of charge of the battery module(s) and / or health of the battery module(s). In this way, the operation of the battery module(s) can be adjusted based on the performance / operation of other battery module(s) (in the series string within the same charger unit, or in a different charger unit), for example, to compensate for anomalies in the performance of the battery modules. This adjustment in operation based on cell information may be determined and / or performed by the local controllers. Thus, the battery module(s) can proactively decide howto balance themselves based on the state / performance of other battery module(s). Optionally, each local controller may comprise an output control module configured to selectively modify an output of the respective battery module to control the output of the respective sub-unit. The output control module may be configured to perform one or more of the following: modify the output of the respective battery module to a positive or negative voltage, and / or control the duty cycle of the output of the respective battery module, or transmit the output of the respective battery module as the output of the respective sub-unit without modification, or electrically disconnect the respective battery module from its respective local controller; or electrically disconnect the respective local controller from the MMC. Electrically disconnecting a battery module from its respective local controller in effect bypasses the battery module while allowing its respective local controller to remain in the circuit. This type of bypass control can allow the MMC to retain its series string without any current flow to / from the disconnected battery module. This can be advantageous as often not all battery modules are needed, unless a high voltage is required. The output control module may be configured to pulse-width modulate (PWM) the output of the respective battery module, for example to switch between positive voltage output, negative voltage output, and bypass where the battery module is electrically disconnected from its respective local controller. Electrically disconnecting the respective local controller from the MMC achieves a passive control where the sub-unit is in effect removed from the circuit, thereby breaking the series string providing the MMC. This can be useful for shutting down the system with lots of redundancy. Alternatively, or in addition to the actions discussed above, the output control module may be configured to control the timing of the output of the sub-unit, e.g. such that the outputs from all sub-units are synchronised in time. Each output control module may comprise an electrical circuit configured to perform the actions discussed above. Optionally, each output control module may comprise a half-bridge (H-bridge) circuit. Each half-bridge (H-bridge) circuit may comprise a plurality of switches, e.g. MOSFETs. The MMCs may have any one of a single star topology such as a cascaded H-bridge (CHB) single star topology, a double star topology, or a flying capacitor topology, where the capacitors are replaced with the batteries. Each local controller may have a respective local power supply. Each local power supply may be configured to supply power to components of the local controller. Each local power supply may supply respective different amounts of power to respective different components of the local controller. In some examples, the local power supply maybe configured to supply 3V to a microcontroller of the local controller, 5V to the local communication unit, and 12V to the H-bridge and / or a gate drive circuit. The local power supply may receive its power (e.g. 12V) via a shared power rail (bus) shared between all the local controllers in the BIEVC. Optionally, each local controller may be further configured to monitor one or more parameters associated with performance of the respective sub-unit. To this end, each local controller may comprise a monitoring unit. Each local controller may be configured to monitor any one or any combination of: voltage of the respective battery module, temperature of the respective battery module, current through the local controller, temperature of the local controller. Monitoring the voltage of the battery module may include monitoring the voltage of each battery cell within the battery module. Similarly, monitoring the temperature of the battery module may include monitoring the temperature of each battery cell within the battery module. Monitoring may be continuous or discrete (e.g. periodic). In some examples, the local controller may be configured to obtain one or more instantaneous temperature / voltage values (points) over time. Each local controller may be further configured to determine a state of charge and / or health of its respective battery module based on some or all of the monitored parameters. The monitored parameters and / or the state of charge and / or health of the battery module may be transmitted to the master controller. The monitored parameter(s) and / or the state of charge and / or health of the battery module may be used as feedback data. The feedback data may be used in selecting how / whether to modify the output of the battery module. For example, each local controller may be configured to send the monitored parameter(s) and / or the state of charge and / or health of the battery module to the master controller (e.g. via the local PDU as discussed below). The master controller may be configured to then determine whether or how the output of each battery module should be modified, and communicate instructions to the local controllers accordingly. Thus, in some examples, each local controller may be configured both to control the output of its respective battery module / sub-unit, and to monitor parameters associated with performance of the respective sub-unit. Optionally, each charger unit may further comprise a local power distribution unit, PDU. Each local PDU may be a printed circuit board (PCB). Each local PDU may be directly or indirectly electrically connectable, e.g. in series, to some or all of the sub-units in the charger unit. More specifically, each local PDU may be directly or indirectly electrically connectable to some or all of the local controllers in the subunits. For example, each local PDU may be electrically connectable to the sub-unit(s) / local controller(s) in the respective charger unit via an RS485 interface. In some examples, each local PDU may be electrically connected in series to its respective neighbouring sub-module in the series of sub-modules. As discussed above, the output control module of each local controller may be used to electrically disconnect selected local controllers from the series string, and thus the local PDU may be in effect electrically connected to a sub-unit which is not its nearest neighbouring sub-unit in the series string. Each local PDU may comprise a respective local power inlet and a respective local power outlet. The local power inlets and local power outlets are used to connect the charger units in parallel to each other and / or to the master PDU, e.g. via a shared power rail. Optionally, each local PDU may further comprise an intermediate controller configured to control an output of the respective charger unit. Each intermediate controller may be configured to use a closed-loop control to keep the voltage / current produced by its respective MMC within limits specified by the master controller. This may involve measuring the voltage / current produced by the charger unit, checking against a predetermined condition such as demand, and altering control commands sent to some or all of the local controllers, to implement the desired voltage / current changes. Each local controller may be communicatively coupled to the master controller via the local PDU (e.g. via the local PDU’s intermediate controller) in the respective charger unit. In this way, the local PDU (e.g. the intermediate controller) can receive communications (e.g. in the form of digital signals) from the master controller, and transmit the communications to each local controller (e.g. to its local communication unit) so as to control the output of each sub-unit. Each local PDU (e.g. each intermediate controller) may be communicatively coupled to the master controller and / or to each local controller via a bus and / or a data transfer cable such as a fibre optics cable, a CAN cable, or a RS485 cable. Each intermediate controller may monitor parameters associated with performance of the respective charger unit. For example, each intermediate controller may be configured to monitor any one or any combination of: voltage of the respective MMC, current through the intermediate controller, and / or temperature of the intermediate controller. The monitored parameters may be transmitted to the master controller. The monitored parameter(s) may be used as feedback data. The feedback data may be used in selecting whether / how to control the output of the charger unit. For example, each intermediate controller may be configured to send the monitored parameters) to the master controller. The master controller may be configured to then determine whether or how the output of each battery module should be modified, and communicate instructions to the intermediate controllers accordingly. Optionally, the charger units may be electrically connected in parallel to one another via a shared power rail, and the charger units are further electrically connectable to the master PDU via the shared power rail. The master PDU may be electrically connectable to the grid using a CCS2 interface, which is universally compatible with a broad range of EVs. The output of the MMCs may be directly connected to the CCS2 DC output, allowing demand for specific voltage / current to dictated by the EV itself. Optionally, the BIEVC may be configured to exchange electrical energy with the grid bi-directionally. To this end, the master power outlet may be electrically connectable to the power grid. The bi-directional exchange of electrical energy may be achieved by controlling power transfer with the grid as a positive or negative value. The bi-directional transfer of electrical energy may be at least partially controlled using a computer program executed by one or more of the controllers of the BIEVC, such as one or more of the local controllers and / or one or more of the intermediate controllers. Optionally, the master PDU may be further electrically connectable to a renewable energy source. In this way, the BIEVC can receive electricity from a renewable energy source, instead of, or in addition to electricity from the grid. For example, the renewable energy source may be a solar energy source. The master PDU may comprise a renewable energy module communicatively and / or electrically connectable to the renewable energy source. The master PDU may comprise an EV charge module communicatively and / or electrically connectable to an EV. The master PDU may comprise the master controller. The master controller may be a circuit board. The master controller may comprise a power control module. The power control module may be communicatively coupled to the EV charge module and / or the renewable energy module and / or to the local PDUs to communicate power information, such as power control instructions during EV charge. The master controller, e.g. the power control module, may be configured to transmit communications (e.g. in the form of digital signals) to the local controllers, e.g. via the intermediate controllers of the local PDUs. The communications may comprise power control instructions for execution by the local controllers. In some examples, the power control module may communicate with the EV to determine charging requirements, and based on this, transmit power control instructions (e.g. in the form of digital signals) to the local controllers, e.g. via the intermediate controllers, to ensure that the desired currents / voltages are produced by the charger units to meet the EV’s charging requirements. Additionally, or alternatively, the master controller may be configured to determine power control instructions based on information obtained from the renewable energy source e.g. via the renewable energy module. The power control module may be coupled to the EV charge module via an Ethernet connection, or a CAN connection. The power control module may be coupled to the local PDUs via a CAN connection or an RS485 connection. The power control module may be a commercially available STM32H745 microcontroller. The master controller may further comprise a connectivity control module. The power control module may be coupled to the connectivity control module via an RS485 connection or an Ethernet connection. The connectivity control module may be configured to connect to external systems, such as the grid, e.g. via WiFi or LoRa, or Ethernet. For example, the connectivity control module may be configured to obtain grid data (such as meter / prices data) from the grid, e.g. in real time. Based on this information, power control instructions may be generated. The power control instructions may for example specify whether the BIEVC should be discharging or charging. The power control instructions may be executable by the charger units, or by the local controllers of the BIEVC. The generation of the power control instructions may be performed by one of the BIEVC’s controllers, such as the master controller, and more specifically, by the power control module. That is, in some examples, the connectivity control module may be configured to obtain grid data, and the power control module may be configured to use the obtained grid data as input, and to output power control instructions generated based on the input grid data (i.e. based on the obtained grid data that has been provided as input into the power control module). The connectivity control module may be communicatively coupled to the power control module, e.g. to transmit the obtained grid data to the power control module. Alternatively, the generation of the power control instructions may be performed by a user. In this case, the connectivity control module may receive commands from the user that specify behaviours (i.e. power control instructions) that the BIEVC should employ / implement. The connectivity control module may be programmable controller such as a Raspberry Pi or a Linux controller. The master controller, e.g. the power control module, may be configured to determine control instructions for execution by the local controllers based on information obtained from the grid e.g. via the connectivity control module. Optionally, the BIEVC may comprise a heat management system. The heat management system may comprise one or more heat management elements, e.g. one or more fans. Alternatively, or additionally, the heat management system may be a liquid cooling system. The heat management system may be electrically powered by an electrical power source, e.g. the grid, or by a battery comprised by the BIEVC. In a second aspect, there is provided a charger unit for use with the BIEVC of the first aspect, the charger unit comprising a plurality of sub-units each comprising a battery module and a local controller electrically connected thereto, wherein the local controllers of the plurality of sub-units are electrically connected to one another in series to form a modular multilevel converter, MMC. The charger unit of the second aspect may include any one or any combination of the features described with reference to the first aspect except where such a combination is clearly impermissible or expressly avoided. More broadly, the invention includes the combination of the aspects and preferred features described except where such a combination is clearly impermissible or expressly avoided. Summary of the Figures Embodiments and experiments illustrating the principles of the invention will now be discussed with reference to the accompanying figures in which: Figure 1 schematically shows examples of a battery-integrated electric vehicle charger described herein. Figure 2 schematically shows examples of a battery-integrated electric vehicle charger described herein. Figure 3 schematically shows an example of a sub-unit for use in the battery-integrated electric vehicle charger described herein. Figure 4 schematically shows an example of a local power distribution unit for use in the battery-integrated electric vehicle charger described herein. Figure 5 schematically shows an example of a master controller for use in the battery-integrated electric vehicle charger described herein. Figure 6 schematically shows example connections between components of an EV charging system. Detailed Description of the Invention Aspects and embodiments of the present invention will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned in this text are incorporated herein by reference. The present disclosure provides a battery-integrated electric vehicle charger (BlEVC) 100 for charging an electric vehicle. Briefly, the BIEVC 100 is configured to facilitate rapid charging of EVs through a Combined Charging System 2 (CCS2) output, drawing power from a power grid connection. An example implementation of the BIEVC 100 is described below with reference to Figures 1 and 2. The BIEVC 100 comprises a plurality of charger units 20 electrically connected to one another in parallel, a master controller 60, and a master power distribution unit (PDU) 50. In this example, the master PDU 50 comprises the master controller 60. The master PDU 50 is electrically connected to the plurality of charger units 20 in parallel. The master PDU 50 is electrically connectable to the power grid 80 through a CCS2 interface, via the AC connection shown in Figure 1. The master PDU is electrically connectable to the power grid 80 in a bi-directional manner such that the BIEVC 100 can selectively receive electricity from and supply electricity to the grid. The master PDU 50 is further electrically connectable to an electric vehicle for charging, via a DC charge cable. Specifically, in this example, the master PDU 50 comprises an EV charge module 52 couplable to an EV for charging. The EV charge module 52 may be electrically, and optionally communicatively couplable to the EV. The master PDU 50 is also electrically connectable to a renewable energy source. Specifically, in this example, the master PDU 50 comprises a renewable energy module 54 couplable to the renewable energy source. The renewable energy module 54 may be electrically, and optionally communicatively couplable to the renewable energy source. In this example, the renewable energy source is a solar energy source. Each charger unit 20 comprises a plurality of sub-units 10. Each sub-unit 10 comprises a respective battery module 22 and a local controller 21 electrically connected thereto. Each local controller is a PCB such as commercially available STM32 controller, e.g. an STM32F0 controller. Each battery module 22 may comprise a plurality of battery cells (not shown). The local controllers 21 of the plurality of sub-units 10 in each charger unit 20 are electrically connected to one another in series to form a modular multilevel converter, MMC 30. The output of each MMC is directly connected to the CCS2 DC output. In this example, each MMC 30 has a cascaded H-bridge (CHB), single star topology. The CHB topology ensures high efficiency in energy conversion, providing flexibility in managing various charging rates and adapting to different EV specifications. Each charger unit 20 further comprises a respective local power distribution unit (PDU) 40. Each local PDU 40 is electrically connected in series to the plurality of sub-units 10 in its respective charger unit 20. Specifically, as shown in Figure 2, each local PDU 40 is electrically connected in series to its respective neighbouring sub-module 10 in the series of electrically connected sub-modules. Each local PDU 40 can be implemented as a commercially available STM32F407 component. The charger units 20 are electrically connected in parallel to each other via their local PDUs 40, and more specifically, via local power inlets 31 and local power outlets 32 of the local PDUs 40. The master controller 60 is communicatively coupled to the plurality of local controllers 21 via the local PDUs to control an output of one or more of the sub-units 10. As shown in Figure 2, the charger units 20 are electrically connected to one another, and to the master controller 60 via a shared power rail 67. Thus, the BIEVC 100 disclosed herein provides a scalable architecture for battery integrated / buffered charging. Specifically, by electrically connecting the charger units 20 in parallel to one another, it can be ensured that the output current from the BIEVC (e.g. DC for EV charging) can be easily scaled up or down respectively with the addition or removal of charger units 20 and / or sub-units 10, as indicated by the two-dimensional arrows in Figures 1 and 2. The BIEVC described herein also comprises a heat management system comprising a plurality of fans 29. Each charger unit 20 includes a respective fan 29, as shown in Figure 1. The fans are powered by an electrical power source, e.g. the grid 80. Example implementations of components suitable for use with the BIEVC disclosed herein are discussed with reference to Figures 3, 4, and 5. Specifically, Figure 3 schematically shows an example of a sub-unit 10 for use in the BIEVC 100 of Figure 1 or 2. The battery module 22 is in direct physical contact with its local controller 21. The local controller 21 is a printed circuit board (PCB). The local controller 21 comprises a local communication unit 25 communicatively coupled to the master controller 60. The local communication unit 25 is communicatively coupled to the master controller 60 indirectly via an intermediate controller 41 of the local PDU 40 of the respective charger unit 20, as described in more detail below with reference to Figure 4. Direct / indirect communicative coupling may be achieved for example via a bus and / or a data transfer cable such as a fibre optics cable. The local controller 21 also comprises an output control module 28 configured to selectively modify an output of the battery module 22 to control the output of the sub-unit 10. Specifically, the output control module 28 is configured to perform one or more of the following: modify the output of the battery module 22 to a positive or negative voltage, and / or control the duty cycle of the output of the battery module 22, or transmit the output of the respective battery module 22 as the output of the sub-unit 10 without modification, or electrically disconnect the battery module 22 from the local controller 21; or electrically disconnect the local controller 21 from the MMC 30. The output control module 28 is configured to pulse-width modulate (PWM) the output of the battery module 22, for example to switch between positive voltage output, negative voltage output, and bypass where the battery module 22 is electrically disconnected from the local controller 21. Optionally, the output control module 28 can also control the timing of the output of the sub-unit 10, e.g. such that the outputs from all sub-units 10 are synchronised in time. The output control module 28 comprises a half-bridge (H-bridge) circuit configured to perform the actions discussed above. The half-bridge (H-bridge) circuit comprises a plurality of MOSFET switches. The H-bridge circuit 28 is driven by a gate drive 27. The local controller 21 has a monitoring unit 24 configured to monitor parameters including battery cell voltages of the cells in the battery module 22, temperature of the battery cells, voltage of the battery module 22, current through the local controller 21, and temperature of the local controller 21. Monitoring can be continuous or discrete (e.g. periodic). The monitoring unit 24 is configured to calculate the voltage of the battery module based on the individual battery cell voltages, for example, by adding up the individual battery cell voltages. In this example, the terminals of the battery module 22 connect directly to the H-bridge for high current output. In this example, the local controller 21, and more specifically its microcontroller 26, is configured to determine a state of charge and / or health of the battery module 22 based on some or all of the monitored parameters described above. The local controller 21 is configured to send the monitored parameters, the state of charge and / or health of the battery module 22 as feedback data to the master controller 60 via the intermediate controller 41 of the local PDU 40 as discussed below). The master controller 60 is configured to then determine whether or how the output of the battery module 22 should be modified, and communicate instructions to the local controller 21 accordingly. The local controller 21 is communicatively coupled to the intermediate controller 41 and thus to the master controller 60 via its local communication unit 25. The local controller 21 can thus receive power control instructions and cell information from the master controller via the local communication unit 25. In this example, the cell information comprises information about neighbouring battery modules 22 such as voltage and / or temperature of the respective battery module(s), and / or current through the local controller(s) 21, and / or temperature of the local controller(s) and / or state of charge of the battery module(s) and / or health of the battery module(s). In this way, the operation of the battery module(s) 22 can be adjusted based on the performance / operation of other battery module(s) 22, for example, to compensate for anomalies in the performance of the battery modules. This adjustment in operation based on cell information may be determined and / or performed by the local controllers 21. Thus, the battery module(s) 22 can proactively decide how to balance themselves based on the state of other battery module(s). The local controller 21 has a local power supply 23. The local power supply 23 is configured to supply power to components of the local controller (PCB) 21. The local power supply 23 can supply different amounts of power to respective different components of the local controller. Specifically, in this example, the local power supply 23 is configured to supply 3V to the microcontroller 26, 5V to a local communication unit 25, and 12V to the H-bridge 28 and gate drive 27 circuits. The local power supply receives its power (e.g. 12V) from the shared power rail 67 (bus) shared between all the local controllers 21 in the BIEVC 100. Next, Figure 4 schematically shows an example of a local PDU 40 for use in the BIEVC of Figures 1 and 2. The local PDU 40 is a printed circuit board (PCB). The local PDU is electrically connectable to the series string of local controllers 21 in the charger unit 20 via an RS485 interface. The local PDU 40 further comprises an intermediate controller 41 configured to control an output of the charger unit 20. The intermediate controller 41 is configured to use a closed-loop control to keep the voltage / current produced by the respective MMC 30 within limits specified by the master controller 60. This involves measuring the voltage / current produced by the charger unit 20, checking against a predetermined condition such as demand, and altering control commands sent to some or all of the local controllers 21, to implement the desired voltage / current changes. As mentioned above, each local controller 21 is communicatively coupled to the master controller 60 via the intermediate controller 41 of the local PDU 40 in the respective charger unit 20. In this way, the intermediate controller 41 can receive communications (e.g. in the form of digital signals) from the master controller 60, and transmit the communications to the local communication unit 25 of each local controller 21 so as to control the output of each sub-unit 10. Each intermediate controller 41 is communicatively coupled to the master controller 60 and / or to each local controller 21 via a bus and / or a data transfer cable such as a fibre optics cable, a CAN cable, or a RS485 cable. The intermediate controller 41 is configured to monitor parameters associated with performance of the respective charger unit 20. Specifically, the intermediate controller 41 is configured to monitor any one or any combination of: voltage of the respective MMC 30, current through the intermediate controller 41, and / or temperature of the intermediate controller 41. To this end, the local PDU 40 comprises current sensors 43, voltage sensors 42 and a temperature sensor 44. The intermediate controller 41 is configured to send the monitored parameter(s) to the master controller 60 as feedback data. The master controller 60 is configured to then determine whether or how the output of each battery module 22 in the respective charger unit 20 should be modified, and communicate power control instructions to the intermediate controllers 21 accordingly. The intermediate controller 41 is configured to send power control instructions to the local controllers 21 via a universal asynchronous receiver / transmitter (UART) protocol. The intermediate controller 41 is configured to receive monitored parameters, such as cell data, from the local controllers 21 via an isoSPI communication interface. The local PDU 40 of Figure 4 further comprises a 250pH / 75A inductor coil 47, a fuse 46, a contactor on the AC line, and a contactor drive for driving the contactor. Finally, the intermediate controller can also receive input voltage, e.g. around 12V, for powering auxiliary components in the BIEVC such as a fan(s) of a heat management system, as shown in Figure 4. Next, Figure 5 schematically shows an example of a master controller 60 for use in the BIEVC of Figures 1 and 2. The master controller 60 is a circuit board. The master controller 60 comprises a power control module 71 and a connectivity control module 70. The power control module 71 is communicatively coupled to the EV charge module 52, the renewable energy module 54, and the local PDUs 40 to communicate power information, such as power control instructions during EV charge. For example, the power control module 71 may communicate with the EV to determine charging requirements, and based on this, transmit power control instructions (e.g. in the form of digital signals) to the local controllers 21, e.g. via the intermediate controllers 41, to ensure that the desired currents / voltages are produced by the charger units 20 to meet the EV’s charging requirements. The power control module 71 may be coupled to the EV charge module 52 via an Ethernet connection, or a CAN connection. The power control module 71 may be coupled to the local PDUs 40 via a CAN connection or an RS485 connection. The power control module 71 may be coupled to the connectivity control module 70 via an RS485 connection or an Ethernet connection. The power control module 71 may be a commercially available STM32H745 microcontroller. The connectivity control module 70 is configured to connect to the grid 80, e.g. via WiFi or LoRa, or Ethernet. The connectivity control module 70 is configured to obtain grid data (such as meter / prices data) from the grid 80, e.g. in real time. Based on this information, power control instructions may be generated. The power control instructions may for example specify whether the BIEVC 100 should be discharging or charging. The power control instructions may be executable by the charger units 20, or by the local controllers 21 of the BIEVC 100. In some examples, the generation of the power control instructions is performed by one of the BIEVC’s controllers, such as the power control module 71. That is, in some examples, the connectivity control module 70 is configured to obtain grid data, and the power control module is configured to use the obtained grid data as input, and to output power control instructions generated based on the input grid data. To this end, the connectivity control module 70 is communicatively coupled to the power control module 70. Alternatively, the generation of the power control instructions can be performed by a user. In this case, the connectivity control module 70 is configured commands from the user that specify behaviours (i.e. power control instructions) that the BIEVC 100 should employ / implement. The connectivity control module may be programmable controller such as a Raspberry Pi or a Linux controller. The circuit board providing the master controller 60 also comprises electrical connections to the shared power rail 67, to the EV charge module 52 (“DC charge” in Figure 5 which is a DC output that connects directly to an EV charging port), to the grid and the renewable energy module 54 (which may be a permanent AC connection to the grid and / or renewable energy module, e.g. to charge the BIEVC itself), and to a 3-pin plug. The electrical connection to the 3-pin plug is an optional output, allowing a user to plug any standard appliance into the system as a simple power outlet. The master controller 60 also comprises temperature sensors 63 for sensing the temperature of the circuit board, current sensors 62, various voltage sensors 16 including a main voltage sensor 61a (pre-and post- contactor 64), DC voltage sensors 61b (pre- and post- contactor 64), voltage sensors 61c (pre-and post- contactor 64b), and grid voltage sensors 61 d (pre- and post- contactor 64b). The master controller 60 also comprises contactors including pos contactor 64a, live contactors 64b, and a neutral contactor 64c. The master controller 60 also comprises fuses 66, RCDs (residual current drives) 65, DC isolation monitoring 68, an isolated supply 69, and an inductor coil 73. Finally, Figure 6 schematically shows example connections between components of an EV charging system, which have already been discussed above with reference to the previous figures. The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof. While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention. For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations. Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described. Throughout this specification, including the claims which follow, unless the context requires otherwise, the word “comprise” and “include”, and variations such as “comprises”, “comprising”, and “including” will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment. The term “about” in relation to a numerical value is optional and means for example + / -10%.

Claims

1. A battery integrated electric vehicle charger, BIEVC, for charging an electric vehicle, the BIEVC comprising:a plurality of charger units electrically connected to one another in parallel, each charger unit comprising:a plurality of sub-units each comprising a battery module and a local controller electrically connected thereto, wherein the local controllers of the plurality of sub-units are electrically connected to one another in series to form a modular multilevel converter, MMC;the BIEVC further comprising:a master controller communicatively coupled to the plurality of local controllers to control an output of one or more of the sub-units; anda master power distribution unit, PDU, electrically connectable to a power grid, and to an electric vehicle for charging, wherein the master PDU is further electrically connectable to the plurality of charger units.

2. The Bl EVC of claim 1, wherein each local controller comprises an output control module configured to selectively modify an output of the respective battery module to control the output of the respective sub-unit.

3. The Bl EVC of claim 2, wherein the output control module is configured to perform one or more of the following:modify the output of the respective battery module to a positive or negative voltage, and / or control the duty cycle of the output of the respective battery module, ortransmit the output of the respective battery module as the output of the respective sub-unit without modification, orelectrically disconnect the respective battery module from its respective local controller; or electrically disconnect the respective local controller from the MMC.

4. The BIEVC of claim 2 or 3, wherein each output control module comprises a half-bridge circuit.

5. The BI EVC of any one of the preceding claims, wherein each local controller is configured to monitor one or more parameters associated with performance of the respective sub-unit.

6. The BBEVC of claim 5, wherein each local controller is configured to monitor any one or any combination of: voltage of the respective battery module, temperature of the respective battery module, current through the local controller, temperature of the local controller.

7. The BI EVC of any one of the preceding claims, wherein each charger unit further comprises a local power distribution unit, PDU, wherein each local PDU comprises a respective local power inlet and a respective local power outlet, and each local PDU is electrically connectable to each submodule in the charger unit.

8. The BIEVC of claim 7 wherein each local PDU further comprises an intermediate controller configured to control an output of the respective charger unit, wherein the master controller is communicatively coupled to the plurality of local controllers via the intermediate controllers.

9. The BI EVC of any one of the preceding claims, wherein the charger units are electrically connected in parallel to one another via a shared power rail, and the charger units are further electrically connectable to the master PDU via the shared power rail.

10. The BI EVC of any one of the preceding claims, wherein the master controller comprises a power control module and a connectivity control module, wherein the connectivity control module is configured to obtain grid data, and the power control module is configured to use the obtained grid data as input, and to output power control instructions generated based on the input grid data.

11. The BIEVC of claim 10 wherein the power control module is configured to determine and / or transmit control instructions for execution by the local controllers based on information obtained from the grid and / or the EV.

12. The BIEVC of any one of the preceding claims wherein the master PDU is further electrically connectable to a renewable energy source.

13. The BI EVC of any one of the preceding claims wherein the BIEVC is configured to exchange electrical energy with the grid bi-directionally.

14. A charger unit for use with the Bl EVC of any one of the preceding claims, the charger unit comprising a plurality of sub-units each comprising a battery module and a local controller electrically connected thereto, wherein the local controllers of the plurality of sub-units are electrically connected to one another in series to form a modular multilevel converter, MMC.03 07 25AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS:-Claims:

1. A battery integrated electric vehicle charger, BIEVC, for charging an electric vehicle, the BIEVC comprising:a plurality of charger units electrically connected to one another in parallel, each charger unit5 comprising:a plurality of sub-units each comprising a battery module and a local controller electrically connected to the battery module, wherein the local controllers of the plurality of sub-units are electrically connected to one another in series to form a modular multilevel converter, MMC;the BIEVC further comprising:10 a master controller communicatively coupled to the plurality of local controllers to control an output of one or more of the sub-units; anda master power distribution unit, PDU, electrically connectable to a power grid, and to an electric vehicle for charging, wherein the master PDU is further electrically connectable to the plurality of charger units;15 wherein:each charger unit further comprises a local power distribution unit, PDU, wherein each local PDU comprises a respective local power inlet and a respective local power outlet, and each local PDU is electrically connectable to each sub-module in the charger unit;each local PDU further comprises an intermediate controller configured to control an output of the20 respective charger unit, wherein the master controller is communicatively coupled to the plurality of local controllers via the intermediate controllers.the master controller comprises a power control module and a connectivity control module, wherein the connectivity control module is configured to obtain grid data, and the power control module is configured to use the obtained grid data as input, and to output power control instructions generated 25 based on the input grid data; andthe power control module is configured to determine and / or transmit control instructions for execution by the local controllers based on information obtained from the grid and / or the EV.

2. The Bl EVC of claim 1, wherein each local controller comprises an output control module30 configured to selectively modify an output of the respective battery module to control the output of the respective sub-unit.

3. The Bl EVC of claim 2, wherein the output control module is configured to perform one or more of the following:35 modify the output of the respective battery module to a positive or negative voltage, and / orcontrol the duty cycle of the output of the respective battery module, ortransmit the output of the respective battery module as the output of the respective sub-unit without modification, orelectrically disconnect the respective battery module from its respective local controller; or40 electrically disconnect the respective local controller from the MMC.07 254. The BIEVC of claim 2 or 3, wherein each output control module comprises a half-bridge circuit.

5. The BI EVC of any one of the preceding claims, wherein each local controller is configured to monitor one or more parameters associated with performance of the respective sub-unit.

56. The BI EVC of claim 5, wherein each local controller is configured to monitor any one or any combination of: voltage of the respective battery module, temperature of the respective battery module, current through the local controller, temperature of the local controller.10 7. The BI EVC of any one of the preceding claims, wherein the charger units are electricallyconnected in parallel to one another via a shared power rail, and the charger units are further electrically connectable to the master PDU via the shared power rail.

8. The BI EVC of any one of the preceding claims wherein the master PDU is further electrically 15 connectable to a renewable energy source.

9. The BI EVC of any one of the preceding claims wherein the BIEVC is configured to exchange electrical energy with the grid bi-directionally.20 10. A charger unit for use with the Bl EVC of any one of the preceding claims, the charger unitcomprising a plurality of sub-units each comprising a battery module and a local controller electrically connected thereto, wherein the local controllers of the plurality of sub-units are electrically connected to one another in series to form a modular multilevel converter, MMC.

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