Off-grid high power (level 2-4) DC (direct current) charging system connectable directly to renewable energy sources, and method for charging an electric or hybrid vehicle

Abstract

A high-power charging system and a method for charging electric vehicles EVs and / or plug-in hybrid vehicles PHEVs are described that allow for versatile charging one or more vehicles, subsequently or at the same time, with a simplified logistics, eventually in a modular way, and minimum set up work and while operating off-grid, i.e. without being connected to an AC electrical network. The system is an off-grid, integrated and prefabricated apparatus comprising plugs or connectors for vehicles, and means for connecting with sources of electricity from renewable energy, like photovoltaic panels and wind turbines organized in isles. The system also comprises a storage unit, provided with batteries and / or capacitors, a DC power unit supplying direct current DC to the plugs or connectors. The DC power unit is provided with one or more DC-DC converters that serve to adjust the voltage provided at said plugs or connectors. An internal distribution grid directly connects the sources of electricity from renewables to a charging controller that itself supplies the storage unit and the DC power unit. The storage unit instantly supplies the power necessary to meet the demand when the sources of electricity from renewables are insufficient. The system can support DC power charging levels two, three and four.

Description

[0001] Off-grid high power (level 2-4) DC (direct current) charging system connectable directly to renewable energy sources, and method for charging an electric or hybrid vehicle ***

[0002] DESCRIPTION

[0003] Field of the Invention

[0004] The present invention refers to an off-grid high power DC (direct current) charging system connectable directly to renewable energy sources, in particular high power at levels 2 to 4, and a method for charging an electric or a plug-in hybrid vehicle.

[0005] State of the art

[0006] An electric vehicle is often referred to using initials EV; similarly, a plug-in hybrid vehicle is referred to using the initials PHEV. In the following, both initials and full names of the vehicles will be used, interchangeably, together with the generic word vehicle.

[0007] As known, an electric vehicle EV is a vehicle that uses one or more electric motors for propulsion. Nowadays road and marine vehicles are available that are equipped with an onboard battery pack to supply power to the electric motor(s). Among common electric vehicles there are, for instance, electric bicycles, automobiles, motorbikes, trucks, trains, vans and buses. Recently, also electric airplanes are being tested.

[0008] The battery pack of an electric vehicle constitutes an onboard storage of chemical energy that is converted into electricity to achieve propulsion; therefore, a battery pack must be periodically recharged to guarantee a given range for the vehicle.

[0009] Most electric vehicles EVs use lithium-ion batteries (Li-Ions or LIBs). Lithium-ion batteries have higher energy density, longer life span and higher power density than most other practical batteries. In the past, nickel-metal hydride batteries were used, but they are now technologically outdated.

[0010] Charging the battery pack of an electric vehicle is normally achieved by connecting the battery pack to a power source, with a cable, when the vehicle is parked.

[0011] A plug-in hybrid electric vehicle PHEV is a hybrid electric vehicle, featuring both an electric motor and an internal combustion engine, whose battery pack can be recharged internally, by a generator powered by the internal combustion engine, and / or by plugging a charging cable into an external electric power source. Most PHEVs are passenger cars, but there are also PHEV versions of sports cars, commercial vehicles and vans, utility trucks, buses, trains, motorcycles, mopeds, and even military vehicles.

[0012] In a nutshell, both EVs and PHEVs feature a battery pack that has to be charged by plugging a charging cable into an external dedicated power source that is referred in the following as charging station.

[0013] Two main types of charging stations are known: AC (alternate current) charging stations and DC (direct current) charging stations. Both types are usually manufactured as stand-alone columns, wherein a single column powers a single vehicle at each time. Usually, stand-alone charging stations are placed in the nearby of one stall for the vehicle, meaning that one stall and the corresponding charging station define a charging bay that can be used by one user at the time. Public charging bays are typically found street-side or at retail shopping centers, and in other parking areas. Private charging bays are typically found at residences, workplaces, shops and hotels.

[0014] Batteries can only be charged with direct current DC electric power, while most electricity is delivered from the power grid as alternating current AC. For this reason, most electric vehicles have a built-in AC-to-DC converter, commonly known as "onboard charger". Thanks to the built-in AC / DC converter, most EVs can accept both AC and DC power.

[0015] At an AC charging station, AC power from the grid is supplied to the built- in AC / DC converter of the vehicle, which produces DC power to charge the battery.

[0016] DC charging stations facilitate higher power charging by supplying DC power to the vehicle directly, bypassing the onboard built-in AC / DC converter.

[0017] The present application refers to DC charging of vehicles. DC charging stations provide connectors that conform to a variety of international standards. In particular, DC charging stations are commonly equipped with multiple connectors to be able to charge a wide variety of vehicles that utilize competing standards. The charging cable is plugged into the DC charging station and into the EV or PHEV.

[0018] It has to be noted that the charging time of EVs and PHEVs can vary depending on a number of factors like, for example, the capacity of the battery pack, the temperature of the battery pack, the level of charge of the battery pack when DC charging starts, the type of DC charging station, etc.

[0019] The following ranges of power level are known for DC charging:

[0020] - power level up to 43 kW, referred to as level two',

[0021] - power level comprised in the range 50 kW- 350 kWand voltage included in the range 400 V- 800 V, referred to as level three',

[0022] - power level above 1 .000 kW and voltage included in the range 800 V - 1 .000 V, referred to as level four.

[0023] Each level two, three or four provides different charging performance.

[0024] A drawback of the present technology is that, often, in rural areas, national parks, touristic areas touristic nautical centers, remote parking spaces, etc., AC electric networks are not available, or there is a limitation of power availability, while power levels two, three and four described above can only be achieved when the DC charging station is connected to medium voltage or low voltage AC electrical network, that is the electric grid normally available in urban areas.

[0025] On another side, extending a medium / low voltage AC electrical network to such areas involves high costs and it is not attractive, due to the authorizations required and the heavy equipment, the staff and the execution time that are necessary for completing this task.

[0026] In other words, known solutions do not allow to quickly set up a DC charging station without prior providing the AC electric network, while in some situations there is the need to have a DC charging station available even without connection to an AC electric network, meaning that there is the need to have off- grid DC charging stations.

[0027] Another drawback of the known solutions lies in their lack of versatility: often the need arises of setting up a temporary DC charging station in short time, like during a social event in an open field, or in the nearby of a temporary working site, etc., that can be then dismantled without affecting the environment. Known DC charging stations imply alteration of the environment, due to the construction of cabinets and charging bays, the deployment of the electrical AC network, etc..

[0028] Known DC charging stations are not easily scalable: if the need arises of expanding the capability of the charging station, by increasing the number of charging bays or spots, this can be achieved only by building new DC charging stations, with the complications described above.

[0029] Summary of the invention

[0030] The object of the present invention is to provide a DC charging system and a method for DC charging EVs and / or PHEVs that overcome the drawbacks described above, in a simply and relatively inexpensive way.

[0031] In particular, a first object of the present invention is to provide an off-grid DC charging system and a method for off-grid DC charging EVs and / or PHEVs that allow for charging one or more vehicles without being connected to an AC electrical network as the main source of power.

[0032] A second object of the present invention is to provide a DC charging system and a method for DC charging EVs and / or PHEVs that allow for charging one or more vehicles with a simplified logistics, in a modular and scalable way, and minimum set up work.

[0033] Therefore, a first aspect of the present invention concerns the DC charging system according to claim 1 for charging road, nautical or aerial electric vehicles EVs and / or plug-in hybrid vehicles PHEVs.

[0034] The system is designed to operate off-grid, meaning that it is designed to operate without being connected to an electric network, like the AC medium voltage or low voltage electric grid normally available in urban areas. Instead, the system is connectable directly to one or more sources of electricity from renewables, wherein the term renewables indicates sources of renewable energy like, for instance, photovoltaic panels or wind turbines.

[0035] The system is manufactured as an off-grid integrated and prefabricated apparatus comprising:

[0036] - one or more plugs or connectors for direct current DC charging of EVs and / or PH EVs;

[0037] - a DC power unit that supplies direct current DC to the plugs or connectors and comprises one or more DC-DC converters to adjust the voltage provided at the plugs or connectors;

[0038] - a storage unit, provided with batteries and / or capacitors, that may be arranged as independent units or according to an interlaced hybrid scheme;

[0039] - a charging controller connected to the renewable energy sources;

[0040] - an internal distribution grid, that connects the above units and components.

[0041] In particular, the internal distribution grid connects the sources of electricity from renewables to the charging controller and from charging controller to the storage unit and to the DC power unit. In a particular embodiment, the charging controller is directly connected to the renewable energy sources.

[0042] The charging controller manage the power flows provided by the sources of electricity from renewables through the system, by directing the energy to the DC power unit or to the storage unit. If the power provided by the sources of electricity from renewables equals the demand from charging vehicles through the DC power unit, the charging controller direct the power to the DC power unit. If the power provided by the sources is higher than the demand from charging vehicles through the DC power unit, the charging controller direct the excess power to charge the storage unit. If the power provided by the sources of electricity from renewables is lower than the demand from charging vehicles through the DC power unit, the charging controller direct the needed power by discharging the storage unit.

[0043] Also the charging controller protect the storage unit from overcharging, overload, overcurrent and over-discharge.

[0044] The term off-grid, as anticipated above, indicates that the system is designed to operate without being connected to an electric network, like the AC medium voltage or low voltage electric grid normally available in urban areas, but it is intended to be connected to sources of renewable energy like, for example, photovoltaic plants or wind turbines arranged as isolated isles.

[0045] The term integrated indicates that the system comprises all the components described above and does not need further components to be made available on site for starting operating.

[0046] The term prefabricated indicates that the system is built as an apparatus enclosed in a structure that is easily transportable on site, and all components are correctly preassembled in the structure, without need for further mounting, wiring, and the like.

[0047] The storage unit stores electricity to make it available to the DC power unit when the power provided by the sources of electricity from renewables is not sufficient to cover the demand by the vehicles being charged. The system automatically adjusts the supply of power by the storage unit to compensate for the instant power not provided by the external sources.

[0048] The proposed solution brings several advantages over prior art.

[0049] The system, which is prefabricated, can be easily transported and installed at the final destination, that can also be a rural area not served by an electric grid. The installation is reduced to electrical cables connection to the renewable energy source and execution of the earthing of the system. The prefabricated configuration also simplifies maintenance of the system, given that maintenance can be done on site, or at the factory when the system is recovered, but technicians will always work on a same configuration, i.e. all delivered systems have a same internal layout and components. Certifications of the installation are no longer an issue, given that the prefabricated system is factory-tested and already provided by the manufacturer with all the necessary legal certifications required in the area wherein the system is intended to be put in place.

[0050] Connecting to renewable energy sources eliminates the need for the expensive deployment of a new branch of an electrical medium voltage or low voltage network. Relying on renewables contributes to meeting the global carbon footprint objectives.

[0051] The system is scalable and customizable, due to its design described above, that may be defined modular, as it will be explained later.

[0052] The system can connect to multiple renewable energy sources and can supply multiple types of EVs and PHEVs at the same time, or at different times.

[0053] Since the system operates without connection to medium voltage or low voltage electricity distribution networks, in off-grid mode, DC charging of vehicles is ensured also when frequent interruptions in the supply of electricity occur, due defects in the medium and low voltage distribution network.

[0054] Construction works are not needed for installing the system, which is manufactured as a prefabricated and integrated unit, compact, that can be transported on site and simply lodged on the ground. The system is relatively light and integrates a reduced number of components, as it will become clearer in the following. Costs associated to maintenance are, thus, minimized.

[0055] The sources of electricity from renewables provide either direct current DC power, or alternate current AC power. For example, photovoltaic panels provide DC current, unless they are provided with a rectifier, and wind turbines provide AC current.

[0056] In one embodiment, the system is designed to operate with sources of electricity from renewables in DC current. The internal distribution grid connects the sources of electricity to the DC power unit, meaning that the power made available by the renewable sources is provided to the DC power unit and its plugs or connectors. The internal distribution grid comprises a charging controller and connects the sources of electricity to the storage unit by means of the charging controller; this assures that, when needed, at least part of the power made available by the renewable sources is stored in the storage unit, meaning that the batteries and / or the capacitors are recharged.

[0057] In another embodiment, or in the same embodiment just described above, the system is designed to operate also with sources of electricity from renewables in AC current. The internal distribution grid comprises at least one AC / DC converter to convert alternate current AC into direct current DC. The internal distribution grid connects the sources of electricity from renewables to the storage unit by means of the charging controller. This configuration allows for charging the storage unit from an AC current source.

[0058] If the power provided by the sources of electricity from renewables equals the demand from charging vehicles the storage unit is not discharged, otherwise the storage unit provides the remaining power to meet such demand. If the power provided by the sources is higher than the demand from charging vehicles, the excess power can be used to charge the storage unit.

[0059] In the preferred embodiment, at least one plug or connector connects a corresponding EV or PHEV vehicle to a DC-DC converter of the DC power unit, for DC current charging at a power level chosen between:

[0060] - power level up to 43 kW, referred to as level two;

[0061] - power level comprised in the range 50 kW- 350 kWand voltage included in the range 400 V- 800 V, referred to as level three;

[0062] - power level above 1 .000 kW and voltage included in the range 800 V - 1 .000 V, referred to as level four.

[0063] DC-DC converters convert DC voltage from the voltage level provided by the renewable energy source, or by the storage unit, to the level required for charging EVs or PHEVs, thus eliminating the need to use power rectifiers.

[0064] Said DC-DC converters are connected to one plug or connector, for providing fast and even ultra-fast direct current DC charging EVs or PHEVs.

[0065] Providing charging of EVs and PHEVs at power levels two, three and four, as described above, will promote switching from traditional endothermic engine vehicles to electric vehicles, and will facilitate reaching the penetration targets set at European and international level.

[0066] Preferably at least one plug or connector is connected by the internal distribution grid directly to the sources of electricity from renewables, through the charging controller by-passing the storage unit.

[0067] Preferably the storage unit comprises a bidirectional DC-DC converter connected to the capacitors on one side, and to the charging controller at another side. The bidirectional DC-DC converter permits to charge and discharge the capacitors according to the needs, at any given moment in time.

[0068] The internal distribution grid comprises a distribution switchboard for connecting to external sources of electricity from renewables. During installation, operators simply have to wire the sources of renewable energy to the distribution switchboard. Because the charging system is designed as an integrated and prefabricated structure or apparatus, the distribution switchboard is arranged within the structure or apparatus, protected from the external environment, and remains accessible only to authorized operators.

[0069] Preferably the system comprises a control unit with an interface for wired / wireless connection to an internet network, and at least one payment interface for users. The control unit allows for remote management of the charging system, technical monitoring, managing payments and authorizations, etc. For example, a 4G / 5G GSM connection can be established with a remote control center.

[0070] Preferably, the charging system is built as a transportable structure or apparatus provided with earthing means. This design allows for quickly and easily setting up charging systems in any area, even rural areas, being sufficient to have a road for transporting the structure and a nearby source of renewable energy. This solution permits to cover in short time, for example, social events organized in open fields where it would not be possible to set up in short time traditional charging columns that require urbanization work. In a nutshell, this solution makes it possible to transport the apparatus / structure to destination, over a truck, unload the apparatus / structure, set up the electrical earthing and connecting the distribution switchboard to a nearby station of photovoltaic panels or a wind turbine, through cables. At this stage the charging system is ready to run for charging vehicles connected to its connectors.

[0071] Clearly, a company running a fleet of these apparatuses / structures may arrange a plurality of them to set up charging isles according to the need. For example, a car manufacturer that organizes the presentation of new models of EVs or PHEVs, with tens cars available to journalists for testing, may set up charging isles using a plurality of apparatuses / structures, also in areas where no other charging services are available, as long as at least one source of renewable energy is available. Clearly, the same easiness of setting up one or more charging isles occurs when the isles are taken back, at the end of the event: dismantling simply requires disconnecting from the source of renewable electrical energy, undoing the earthing, and loading the structures on trucks.

[0072] This can be described as versatility in terms of logistics.

[0073] Even more preferably the charging system is built as a shipping apparatus or structure, isolated from the external environment, having standard dimensions for international freight shipment. This choice simplifies the logistics.

[0074] According to a preferred embodiment, the charging system is modular. Modularity is obtained by providing the system with means for connecting to another charging system according to the present invention, to achieve a given layout of charging bays. In particular, in the charging system of this embodiment the internal electrical distribution grid may power one or more plugs or connectors of one or more other charging systems. Alternatively, or optionally, the charging system comprises means to share the DC / DC converters according to a desired electrical scheme, in a modular way, with other charging systems.

[0075] Modularity allows for even higher versatility.

[0076] Preferably, plugs or connectors are arranged on the external walls of the structure, or are placed at distance from the apparatus / structure, being wired to it. This solution permits to charge vehicles at a distance from the apparatus / structure, so to adapt the layout of the charging bay to the environment.

[0077] In a nutshell, the charging system described above can be used for DC charging the battery pack of one or more road, nautical or aerial electric vehicles EVs or plug-in hybrid vehicles PHEVs, in different moments or at the same time, at a power level chosen between:

[0078] - power level up to 43 kW, referred to as level two;

[0079] - power level comprised in the range 50 kW- 350 kWand voltage included in the range 400 V- 800 V, referred to as level three;

[0080] - power level above 1 .000 kW and voltage included in the range 800 V - 1 .000 V, referred to as level four, while operating off-grid, i.e. without being connected to an AC electrical network. In particular, vehicles can be charged on direct current DC, fast-charged and ultra-fast (high power) charged.

[0081] A second aspect of the present invention relates to the method of claim 17 for DC charging EVs and / or PHEVs.

[0082] The method is implementable by providing a charging system as described above, and by:

[0083] - connecting, through the internal distribution grid, the sources of electricity from renewables to the said charging controller;

[0084] - connecting, through the internal distribution grid, the charging controller to said storage unit;

[0085] - connecting, through the internal distribution grid, the charging controller to said DC power unit;

[0086] - connecting one or more electric vehicles EVs and plug-in hybrid vehicles PHEVs, in different moments or at the same time, to a corresponding one plug or connector.

[0087] The advantages provided by this method are the same described for the charging system, especially when the charging system is manufactured as a transportable integrated and prefabricated apparatus or structure, isolated from the external environment and provided with earthing means.

[0088] Brief list of the figures

[0089] Further characteristics and advantages of the invention will be more evident by the review of the following specification of a preferred, but not exclusive, embodiment, which is depicted for illustration purposes only and without limitation, with the aid of the attached drawings, in which:

[0090] - figure 1 is a schematic view, and an electrical scheme, of a charging system according to the present invention.

[0091] Detailed description of the invention

[0092] Referring to figure 1 , with reference 1 a charging system according to the present invention is shown in a schematic way. The charging system 1 is preassembled and enclosed in a structure 2, that is also referred to as apparatus 2. Having the system 1 preassembled in a structure 2 makes the system prefabricated.

[0093] The structure or apparatus 2 is electrically isolated from the ground but the system 1 is itself grounded when is set up for running. Moreover, the structure 2 is physically protected from the external environment in order to prevent short- circuits caused by rain.

[0094] Within the structure 2 an internal distribution grid 3 is arranged, which is connected to a distribution switchboard 4 that, in turn, is connectable to a source of renewable electrical energy, through cables 5. In the figures, two sources of renewable electrical energy are shown: photovoltaic panels 20, that provide DC current power, and a wind turbine 21 , that provides AC current power.

[0095] The structure 2 is intended to operate off-grid, meaning that it is not intended to be connected to an AC electrical network, like a city network or a network usually available in urban areas, but it is intended to be connected to sources of renewable energy arranged as isles, like remote photovoltaic plants or single wind turbines, even private ones arranged in rural areas. The distribution switchboards 4 are integrated within the structure 2, in order to stay protected from the environment outside the structure 2. During installation, an operator authorized to access the structure 2 plugs cables 5 into the switchboards 4 to power the system 1 .

[0096] The internal distribution grid 3 distributes the power from the distribution switchboards 4 to the components integrated in the system 1 .

[0097] The system 1 also comprises, within the structure 2, a storage unit 6 and a DC power unit 7. The storage unit 6 has the function of storing the excess power provided by sources 20, 21 , that is the instant power not absorbed by charging vehicles connected the system 1 . The energy stored in the storage unit 6 is made available at any time to the DC power unit, whenever it is necessary to meet the demand by the charging vehicles and the power supplied by sources 20 and 21 is not sufficient.

[0098] Storage unit 6 comprises batteries 8 and / or capacitors 9, in particular ultracapacitors. Batteries 8 and capacitors 9 may be interconnected to define a hybrid storage unit 6.

[0099] A first branch 12 of the internal distribution grid 3 connects the distribution switchboard 4 and the DC current source, that is the photovoltaic panels 20, to the charging controller 10.

[0100] The charging controller 10 fulfils a dual function:

[0101] It controls the power flows provided by the sources of electricity from renewables 20, 21 through the system 1 , by directing the energy to the DC power unit 7 or to the storage unit 6. If the power provided by the sources of electricity from renewables 20, 21 equals the demand from charging vehicles through the DC power unit 7, the charging controller 10 direct the power to the DC power unit 7. If the power provided by the sources 20, 21 is higher than the demand from charging vehicles through the DC power unit 7, the charging controller 10 direct the excess power to charge the storage unit 6. If the power provided by the sources of electricity from renewables 20, 21 is lower than the demand from charging vehicles through the DC power unit 7, the charging controller 10 direct the needed power by discharging the storage unit 6.

[0102] Protect the storage unit 6 from overcharging by regulating the voltage and current coming from the sources of electricity from renewables 20, 21 to the storage unit 6. The charge controller 10 acts as an intelligent protector by stopping battery 8 from the storage unit 6 charging when the voltage level reaches the pre-set threshold. Also the charging controller 10 has the function of overload and overcurrent protection. When running vehicles charging directly from storage unit 6 through the charging controller 10, it monitors the current demand and stops if it exceeds a certain limit to prevent storage unit 6 damage. At the same time provides over-discharge protection and protect the storage unit 6 from being discharged completely.

[0103] A second branch 13 of the internal distribution grid 3 connects the distribution switchboard 4 and the AC current source, that is the wind turbine 21 to the charging controller 10. Along this second branch an AC to DC converter 11 is arranged, having the function of converting the AC current provided by wind turbine 21 into DC current that is supplied to the charging controller 10.

[0104] A third branch 14 of the internal distribution grid 3 connects the charging controller 10 to storage unit 6.

[0105] A fourth branch 15 of the internal distribution grid 3 connects the charging controller 10 to DC power unit 7.

[0106] As it will become clearer in the following, given the different nature of sources 20 and 21 , branches 12 and 13 of the internal distribution grid 3 supply power to the charging controller 10 with different characteristics, branch 14 connects the charging controller 10 with the storage unit 6 and, in the end, branch 15 supplies the DC power unit 7 and, thus, different plugs / connectors 23-24-25.

[0107] DC power unit 7 receives power through branch 15 of the internal distribution grid 3, from the charging controller 10. DC power unit 7 is the unit that comprises, or is connected to, a plurality of plugs / connectors 23-24-25 to which EVs and PHEVs vehicles are connected for DC charging. Fast charging and ultra-fast charging are obtained by equipping the DC power unit 7 with a plurality of DC-DC converters 17 that serve one plug or connector 23-24-25.

[0108] The system includes an internal services unit 16 equipped with DC / AC invertor and used for communication services, lighting etc..

[0109] The system also includes a control unit 19 that integrate program means programmed to automatically configure the electric scheme between the DC-DC converters 17 so to obtain the best charging performance for the specific EVs and PHEVs connected to plugs or connectors 23-24-25 at a given time.

[0110] In particular, control unit 19 instantly sets the connections between the DC- DC converters 17 so to provide a given power level at plugs or connectors 23-24- 25, the power level being chosen between:

[0111] - power level up to 43 kW, referred to as level two;

[0112] - power level comprised in the range 50 kW- 350 kWand voltage included in the range 400 V- 800 V, referred to as level three;

[0113] - power level above 1 .000 kW and voltage included in the range 800 V - 1 .000 V, referred to as level four.

[0114] Also, the control unit 19 allows to connect two or more systems 1 , one with another, to achieve modularity, while always while operating off-grid, i.e. without being connected to an AC electrical network.

[0115] This can be done, for example, by connecting more systems 1 in series or in parallel, or in series-parallel, to expand the number of charging bays.

[0116] Control unit 19 also instantly adjusts the operating mode of system 1 , in order to optimize the charge / discharge time of batteries 8 and the number of charge-discharge cycles of ultra-capacitors 9; in this way, the control unit 19 obtains the best performances from the storage unit 6.

[0117] As explained above, the electrical configuration of system 1 permits to charge a variety of EVs and / or PHEVs, those that have their own AC / DC converter and those that have not.

[0118] By having a plurality of plugs / connectors 23-24-25 supplied with DC current at different power levels, the system 1 allows for charging vehicles, one after another or at the same time, at regular speed, or fast speed or ultra-fast speed, being therefore highly versatile.

[0119] With reference to figures 1 , the system 1 is integrated since all the components needed to operate the system are prearranged in the structure 2. Moreover, the system 1 is also prefabricated, meaning that all the components described above are also correctly connected and arranged one with respect to another in the structure 2 so that the operator does not have to work out connections, wiring and tests once the system 1 has been delivered to destination.

[0120] Certifications required by law can be obtained for the system 1 once built at the factory, and kept after transportation, without necessity to obtain new certifications.

[0121] Since the structure 2 has standard dimensions, it can be transported on trucks, ships and even helicopters. Once delivered, the operator achieves earthing and connection to a source 20, 21 of electricity from renewable energy, like a photovoltaic isle 20, or one or more wind turbines 21. Then, management is achieved remotely and wireless, through the electronic control unit 19.

[0122] Logistics and operation are, therefore, extremely simple and setting up of the system 1 can be obtained with little staff and only one skilled person.

[0123] Modularity is achieved by the system 1 since it can be interconnected with similar systems 1 to obtain the desired layout of charging bays. The system 1 according to a modular embodiment is provided with supplementary cables or lines to allow connection of DC power unit 7 of one system 1 to connectors 23- 24-25 or DC Power unit 7 of another system 1 . Moreover, a modular system 1 may use its internal distribution grid 3 to power connectors 23-24-25 of another system 1 . This modular configuration can also be used to provide some backups.

[0124] The structure 2 may be built with dimensions compatible with international standards for intermodal transportation. On one side of the structure 2 a panel may be provided carrying the plugs or connectors 23-24-25 and providing the electronic control unit 19, preferably with a user interface to manage payments, selective activation of the plugs / connectors 23-24-25, remote control for maintenance through a wireless data network, etc. Earthing means 26 are provided: when the structure 2 is shipped to destination, an operator proceeds to electrically ground the system 1 by trenching earthing means 26 and by connecting cables 5 to the distribution switchboard 4.

[0125] The system 1 is integrated, since all the components needed to operate the system are prearranged in the structure 2. Moreover, the system 1 is also prefabricated, meaning that all the components described above are also correctly connected and arranged one with respect to another in the structure 2 so that the operator does not have to work out connections, wiring and tests once the system 1 has been delivered to destination.

[0126] Certifications required by law can be obtained for the system 1 once built at the factory, and kept after transportation, without necessity to obtain new certifications.

[0127] Since the structure 2 can be built having standard dimensions, it can be transported on trucks, ships and even helicopters. Once delivered, the operator achieves earthing and connection to a source 20, 21 of electricity from renewable energy, like a photovoltaic isle 20, or one or more wind turbines 21. Then, management is achieved remotely and wireless, through the electronic control unit 19. Logistics and operation are, therefore, extremely simple and setting up of the system 1 can be obtained with little staff and only one skilled person.

[0128] Modularity is achieved by the system 1 since it can be interconnected with similar systems 1 to obtain the desired layout of charging bays. The system 1 according to a modular embodiment is provided with supplementary cables or lines to allow connection of DC power unit 7 of one system 1 to connectors 23- 24-25 or DC Power unit 7 of another system 1 . Moreover, a modular system 1 may use its internal distribution grid 3 to power connectors 23-24-25 of another system 1 . This modular configuration can also be used to provide some backups.

Claims

CLAIMS1. A system (1 ) for charging electric vehicles EVs and / or plug-in hybrid vehicles PHEVs, the system (1 ) being connectable directly to one or more sources (20, 21 ) of electricity from renewables, and providing direct current DC charging of EVs and / or PHEVs through one or more plugs or connectors (23-24- 25), wherein the system (1 ) is an off-grid integrated and prefabricated apparatus comprising:- said one or more plugs or connectors (23-24-25);- a DC power unit (7) supplying direct current DC to said one or more plugs or connectors (23-24-25) and provided with one or more DC-DC converters (17) to adjust the voltage provided at said one or more plugs or connectors (23-24- 25);- a storage unit (6), provided with batteries (8) and / or capacitors (9),- a charging controller (10);- an internal distribution grid (3) connecting:- said one or more sources (20, 21 ) of electricity from renewables to said charging controller (10);- said charging controller (10) to said storage unit (6)- said charging controller (10) to said DC power unit (7).

2. The charging system (1 ) according to claim 1 , wherein said sources (20) of electricity from renewables provide direct current DC, and wherein said internal distribution grid (3) connects said sources (20) of electricity from renewables to said DC power unit (7) by means of said charging controller (10), and wherein said internal distribution grid (3) connects said sources (20) of electricity from renewables to said storage unit (6) by means of said charging controller (10).

3. The charging system (1 ) according to claim 1 or claim 2, wherein said sources (21 ) of electricity from renewables provide alternate current AC, and said internal distribution grid (3) comprises at least one AC / DC converter (11 ) to convert alternate current AC into direct current DC, and wherein said internaldistribution grid (3) connects said sources (21 ) of electricity from renewables to said storage unit (6) by means of said at least one AC / DC converter (11 ) and by said charging controller (10).

4. The charging system (1 ) according to any previous claim, wherein at least one plug or connector (23-24-25) connects a corresponding EV or PHEV vehicle to a DC-DC converter (17) of said DC power unit (7), for DC current charging at a power level chosen between:- power level up to 43 kW, referred to as level two',- power level comprised in the range 50 kW- 350 kWand voltage included in the range 400 V- 800 V, referred to as level three',- power level above 1 .000 kW and voltage included in the range 800 V - 1 .000 V, referred to as level four.

5. The charging system (1 ) according to claim 4, wherein at least one or more DC-DC converters (17) are connected to at least one plug or connector (23- 24-25), for fast or ultra-fast direct current DC charging EVs or PHEVs.

6. The charging system (1 ) according to any previous claim, wherein the one or more plugs or connectors (23-24-25) are connected by said internal distribution grid (3) to at least one of said sources (20, 21 ) of electricity from renewables and said storage unit (6) through said charging controller (10).

7. The charging system (1 ) according to any previous claim, wherein at least one plug or connector (23-24-25) is connected by said internal distribution grid (3) and said one or more DC / DC converters (17) directly to said sources (21 ) of electricity from renewables, through an AC / DC converter (11 ) and said charging controller (10), by-passing said storage unit (6).

8. The charging system (1 ) according to any previous claim, wherein at least one plug or connector (23-34-25) is connected by said internal distribution grid (3) and said one or more DC / DC converters (17) directly to said sources (20) of electricity from renewables, through the charging controller (10), by-passing said storage unit (6).

9. The charging system (1 ) according to any previous claim, wherein saidstorage unit (6) comprises a bidirectional DC-DC converter (18) connected to said capacitors (9), and to said charging controller (10).

10. The charging system (1 ) according to any previous claim, wherein said internal distribution grid (3) comprises distribution switchboard(s) (4) for connecting to external sources (20, 21 ) of electricity from renewables.

11. The charging system (1 ) according to any previous claim, comprising a control unit (19) with an interface for wired / wireless connection to an internet network, and at least one payment interface for users.

12. The charging system (1 ) according to any previous claim, being built as a transportable structure (2) provided with earthing means (26).

13. The charging system (1 ) according to claim 12, wherein said one or more plugs or connectors (23-24-25) are arranged on the external walls of the transportable structure (2) or are placed at distance from the transportable structure (2), being wired to it.

14. The charging system (1 ) according to any previous claim, being built as a prefabricated integral or modular structure isolated from the external environment.

15. The charging system (1 ) according to any previous claim, comprising means for connecting to another one or more charging systems (1 ) according to any previous claim, wherein the internal distribution grid (3) of one charging system (1 ) directly powers said one or more plugs or connectors (23-24-25) of one or more other charging systems (1 ) or the DC power unit (7) of one or more other charging systems (1 ).

16. Use of the charging system (1 ) according to any previous claim to charge the battery pack of one or more road, nautical or aerial electric vehicles EVs or plug-in hybrid vehicles PHEVs, in different moments or at the same time, at a power level chosen between:- power level up to 43 kW, referred to as level two',- power level comprised in the range 50 kW- 350 kWand voltage included in the range 400 V- 800 V, referred to as level three',- power level above 1 .000 kW and voltage included in the range 800 V - 1 .000 V, referred to as level four.

17. A method for off-grid charging electric vehicles EVs and plug-in hybrid vehicles PHEVs, characterizing by providing a system (1 ) built as an off-grid, integrated and prefabricated apparatus, comprising:- one or more plugs or connectors (23-24-25);- a DC power unit (7) supplying direct current DC to said one or more plugs or connectors (23-24-25) and provided with one or more DC / DC converters (17) to adjust the voltage provided at said one or more plugs or connectors (23-24- 25);- a storage unit (6), provided with batteries (8) and / or capacitors (9),- a charging controller (10),- an internal distribution grid (3), the method comprising:- connecting, through said internal distribution grid (3), said one or more sources (20, 21 ) of electricity from renewables to said charging controller (10);- connecting, through said internal distribution grid (3), said charging controller (10) to said storage unit (6);- connecting, through said internal distribution grid (3), said charging controller (10) to said DC power unit (7);- connecting one or more electric vehicles EVs and plug-in hybrid vehicles PHEVs, in different moments or at the same time, to a corresponding one of said plugs or connectors (23-24-25).

18. The method according to claim 17, wherein said charging system (1 ) is manufactured as a transportable integrated and prefabricated apparatus, isolated from the external environment and provided with earthing means (26).

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