DE102018204057A1 - Charging station for electric vehicles with at least two charging stations - Google Patents

Abstract

The invention relates to a charging station (10) for electric vehicles with at least two charging stations (12) to each of which an electric vehicle can be charged at the same time, and with an electrical energy storage device (14) electrical energy store (14) has at least two electrically separate storage units (16) that the charging station (10) for each memory unit (16) has a separate bidirectional charge controller (18) that each memory unit (16) is associated with at least one charging station (12) which can be supplied with electrical energy via the memory unit (16), and that in each case a memory unit (16) of the associated bidirectional charge controller (18) and the at least one associated charging station (12) form a storage string (30).

Description

The invention relates to a charging station for electric vehicles with at least two charging stations, to each of which an electric vehicle can be charged at the same time, and with an electrical energy storage.

To increase the comfort for drivers of electric vehicles, it is generally desired to achieve a high range in electric vehicles. At the same time a fast charging should be possible, in which the energy storage can be replenished in the shortest possible time. However, this leads to the fact that very high charging power is necessary, which may not be provided by the power grid operator. Mains connections with approx. 450 kW of power are usually easy to provide. However, even a single vehicle in fast charge mode requires up to 350 kW. From this it is easy to see the problem that when more than two vehicles are to be charged, the power of the power grid connection is insufficient. Therefore, it can be provided to provide an electrical energy storage at the charging station, which can compensate for the lack of power if necessary, and in times in which a few cars are charged, for example, at night, which is replenished.

As expected, such an energy store must undergo very many charge cycles during operation, so that the life of the energy store is not particularly high, and the maintenance intervals are short. However, replacement of the energy storage means that the charging station is not available during this time. Especially in electric vehicles, which in principle have a shorter range than vehicles that are driven by internal combustion engines, it can lead to problems when a charging station is unexpectedly not in operation.

The invention has for its object to provide an improved or at least other embodiment of a charging station for electric vehicles, which is characterized in particular by an improved interchangeability of the energy storage.

This object is achieved by the subject of the independent claim. Advantageous developments are the subject of the dependent claims.

The invention is based on the basic idea to provide more than one energy storage for the charging station, so that during maintenance, the energy storage can be exchanged one after the other, so that the rest of each not in exchange energy storage can continue to operate the charging station. According to the invention, it is provided that the electrical energy store has at least two electrically separate storage units, that the charging station has a separate bidirectional charge controller for each storage unit, that each storage unit is assigned at least one charging station, which can be supplied with electrical energy via the storage unit, and in each case one memory unit of the associated bidirectional charge controller and the at least one associated charging station form a memory string. By separating the energy store into a plurality of separate, electrically separate storage units, the storage units can be exchanged one after the other, so that the respective non-exchanged storage units enable further operation of the charging station. The use of bidirectional charge controllers allows a memory unit of one memory string to provide power to a memory unit of another memory string, or even to supply the necessary electrical power to a memory string in which the memory unit is swapped.

In the description and the appended claims, electric vehicles are understood to mean vehicles which are at least partially driven by an electric motor and have an electrical energy store, for example a rechargeable battery.

In the description and the appended claims, a bidirectional charge controller is understood to be a charge controller which can derive power both from a voltage source in order to charge an energy store and also to remove energy from the energy store and return it to the power source.

In the description and the appended claims, a storage unit is understood to mean, in particular, an energy storage unit for electrical energy.

A favorable possibility provides that the memory strings have a charging operating mode in which the memory unit of the memory string is loaded. Such a charging operation mode is activated, for example, when the requested at the charging stations of electric vehicles electric power is less than the electric power supply made available by the electrical power supply and the corresponding storage unit of the storage string is not full. As a result, although the low power of the grid connection, which is constantly available, can be exploited in order to provide sufficient power at peak times in which a high charging power is required.

Another favorable possibility provides that the memory strings have a power operating mode in which one or more of the associated charging columns additional electrical energy is supplied. If several electric vehicles are charged at the same time at the charging stations, it may happen that the total electrical power requested by the electric vehicles is greater than the electrical power that can be provided by the grid connection. In this case, the missing electrical power is taken from the storage units so that the desired charging power is available for all electric vehicles connected to the charging station.

Another particularly favorable possibility provides that the memory strings have a support mode in which electrical energy is provided via the bidirectional charge controller in order to supply electrical energy to at least one other memory string. This may be necessary, for example, if the storage unit is empty or the charge level falls below a limit at which the lifetime of the storage unit is impaired and at the same time an electric vehicle is connected to the associated charging station and requires power and, in addition, the total charging capacity is greater than that electrical power provided by the grid connection. In this case, another memory string having a filled memory unit, or at least a memory unit having a state of charge that is greater than a second limit, can provide energy and supply it to the memory string, which can no longer take energy from its memory unit ,

An advantageous solution provides that the charging station has a control device, which performs an energy management, and that the control device controls the memory strings in such a way that loading strokes of the memory units are reduced. Due to the different modes of the memory strings can be achieved that the memory units of the memory strings usually have approximately the same state of charge. As a result, overall the maximum loading stroke that can occur on individual storage units is reduced, so that the service life of the storage units can be increased.

An alternative objective of energy management can be to draw as constant a power as possible from the grid connection.

Usually, some charging stations are preferred by motor vehicle drivers who, for example, have a shorter route to a shop or are easier to approach. Therefore, the memory units associated with these charging columns would be more heavily loaded than other storage units. Energy management can compensate for this inequality burden.

A further advantageous solution provides that according to the energy management, if the power available from the grid connection is greater than the total power requested at the charging stations, the excess power is used to charge the storage units, with the storage units having the lowest charge level being preferentially charged , The power available from the grid connection can be individually distributed to the individual memory strings, so that the memory strings that have an already fully charged memory unit, no power is supplied while the memory line, which has the storage unit, with the lowest battery level the most electrical Power is supplied to the store.

In the description and the appended claims, a requested power at the charging stations means the power with which the electric vehicles are to be charged.

A further particularly advantageous solution provides that according to the energy management, if the power available from the grid connection is less than the total power requested at the charging stations, electrical power is provided from the storage units, the additional power being preferably provided by the storage units, whose charging stations are active. In these cases, the electrical energy taken from the storage units need not be transformed back through the bidirectional charge controller. As a result, the occurring conversion losses can be reduced.

In the description and the appended claims, an active charging station is understood to mean a charging station to which an electric vehicle is connected and charged.

An expedient variant provides that, according to the energy management, if the power available from the grid connection is less than the total power requested at the charging stations, and if the charging state of one of the storage units having at least one charging station is below a first limiting value, at least one memory unit of one of the other memory strings provides the missing electrical power. This can avoid that the storage unit in question falls into a state of charge, which affects the life of the storage unit. Furthermore, it can be avoided that the memory unit empties completely. This can be avoided in most cases that the Charging power at the relevant charging station must be reduced.

Providing the additional electrical power from one of the memory strings can be achieved, for example, by using the support mode of one of the memory strings.

Another particularly expedient variant provides that, according to the energy management, when the charge levels of two storage units differ from each other by more than a predetermined limit, electric power is supplied from the storage unit having the higher charge level to the storage unit having the lower charge level to load. As a result, an alignment of the charging states of the individual storage units can be achieved. Overall, thus, the loading stroke of the individual storage units can be reduced, whereby the life of the storage units and thus the energy storage can be increased.

Another particularly expedient variant envisages that if one of the storage units is replaced, if the power available from the grid connection is less than the total power requested at the charging stations, at least one storage strand provides energy to provide the missing power.

An advantageous possibility provides that the charging station for each charging station has a motor vehicle controller, that each such motor controller has a galvanic isolation. This electrical isolation can increase safety for the driver who charges his electric vehicle at the charging station. Due to the high performance otherwise unwanted potential could build up, which could endanger the drivers of the electric vehicles.

A further advantageous possibility provides that the charging station has a mains connection circuit with galvanic isolation. By galvanic isolation to the mains connection, the ground potentials can be secured to the storage units, so that the safety of the entire charging station is increased. In conjunction with car charge controllers with a galvanic isolation, so a double electrical isolation between the electric vehicle and the power supply or the power grid is given, so that a particularly high level of operational reliability is possible.

A further advantageous possibility provides that the mains connection circuit has a rectifier with power factor correction. Typically, network operators provide the grid connection as an AC grid connection. Therefore, it is advantageous if the charging station has a rectifier. The power factor correction can be used to avoid reactive power, which would cause unnecessary costs.

A favorable solution provides that the charging station per charging station has at least one such storage unit.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components.

• 1 ein Blockschaltbild einer erfindungsgemäßen Ladestation,
• 2 ein Blockschaltbild der Ladestation aus 1, wobei Leistungsflüsse durch Pfeile symbolisiert sind, bei einer ersten möglichen Situation,
• 3 ein Blockschaltbild der Ladestation aus 1, wobei Leistungsflüsse durch Pfeile symbolisiert sind, bei einer zweiten möglichen Situation,
• 4 ein Blockschaltbild der Ladestation aus 1, wobei Leistungsflüsse durch Pfeile symbolisiert sind, bei einer dritten möglichen Situation, und
• 5 ein Blockschaltbild der Ladestation aus 1, wobei Leistungsflüsse durch Pfeile symbolisiert sind, bei einer vierten möglichen Situation.

It show, each schematically

• 1 a block diagram of a charging station according to the invention,
• 2 a block diagram of the charging station 1 , where power flows are symbolized by arrows, in a first possible situation,
• 3 a block diagram of the charging station 1 , where power flows are symbolized by arrows, in a second possible situation,
• 4 a block diagram of the charging station 1 , where power flows are symbolized by arrows, in a third possible situation, and
• 5 a block diagram of the charging station 1 , where power flows are symbolized by arrows, in a fourth possible situation.

One in the 1 to 5 illustrated charging station 10 has several, for example, three charging stations 12 to each of which an electric vehicle can be charged, and an energy storage 14 on. The energy storage 14 has several, for example, three storage units 16 on, each storage unit 16 at least one charging station 12 associated with which is the storage unit 16 can supply directly with energy, in particular electrical energy.

Each storage unit 16 is a bidirectional charge controller 18 assigned over which the storage unit 16 can be charged and over which energy can be removed from the storage unit. In addition, each storage unit is a separate car charge controller 20 provided, which can be connected via the charging stations with electric vehicles to charge them.

Finally, there is a power connection circuit 22 provided via which a mains connection 24 with the charging station 10 can be connected.

The power connection circuit 22 preferably has three rectifiers with galvanic isolation and power factor correction. The three rectifiers 26 give electrical power to a primary voltage level 28 from. With this primary voltage level 28 are the bidirectional charge controllers 18 the storage units 16 connected so that via the bidirectional charge controller energy from the primary voltage level 28 to the storage units 16 led and from the storage units 16 to the primary voltage level 28 can be transferred.

The bidirectional charge controller 18 are designed such that over these both the memory units 16 can be charged as well as energy from the storage units 16 can be removed.

The storage units 16 are preferably electric battery storage, for example based on a lithium-ion technology.

The car charge controller 20 preferably also have a galvanic isolation. This is due both to the mains connection circuit 22 as well as the vehicle charge controllers 20 provided a galvanic isolation. Due to this double galvanic isolation, a very high level of operational reliability can be achieved. Each associated bidirectional charge controller 18 , Storage units 16 , Car charge controller 20 and charging stations 12 together form a so-called storage strand 30 , The charging station 10 thus has several, preferably three storage strands 30 on. It is understood that each memory strand 30 also more than a charging station 12 can have. Further, it is understood that the charging station 10 more than three memory strings 30 can have. The charging station 10 is therefore scalable.

Each storage thread 30 has several modes of operation. For example, a loading mode in which the respective storage unit 16 of the storage thread 30 is loaded. This charging mode is used when, for example, at any of the charging stations 12 an electric vehicle is connected and thus the from the mains connection 24 available electrical power is not required for charging electric vehicles. Such a situation is exemplary in 2 shown. The entire electrical power that the grid connection 24 can be taken on the three storage units 16 split up to charge these. The occurring power flow is indicated by the arrows 32 symbolizes, with a thicker arrow means a higher power flow.

Furthermore, the memory strings 30 a power mode of operation. In the power mode of operation, the associated memory units become 16 taken from electrical energy and the vehicle charge controllers 20 the charging stations 12 fed. The power mode of operation of the storage strings is then used when the whole at the charging stations 12 Requested electrical power is greater than that from the electrical mains connection 24 available electrical power. The performance gap is then passed through the storage units 16 refilled. Such a situation is for example in 3 shown. The from the mains connection 24 provided power is initially evenly across the three memory strings 30 divided up. Each storage unit 16 the three memory strings 30 now increases this power, which the car charge controllers 20 is supplied to provide the power required for charging the electric vehicles.

As a result, a quick charging of the electric vehicles can be achieved, even if the total charging power is greater than that of the grid connection 24 available electrical power.

Another operating mode of the memory strings is the so-called support mode. This energy is from the storage unit 16 via the bidirectional charge controller 18 the primary voltage level 28 returned, leaving them in another storage thread 30 can be used. This support mode is used, for example, when a storage unit 16 in one of the storage strings 30 is empty or the charge level is below a specified limit. Required is this support mode, when at the charging stations 12 requested total electrical power is greater than that of the electrical mains connection 24 available electrical power and to the storage string 30 at which the storage unit 16 is empty or has a state of charge that is below a specified limit, an electric vehicle at the charging station 12 hangs. In this case, this storage unit 16 do not provide the missing electrical power. This can then be done by the storage thread 30 , which is operated in the support mode, be compensated. Such a situation is for example in 4 shown. The upper memory string 30 has a storage unit 16 which is empty or whose charge level is below a threshold value. Because in all three charging stations 12 when a load is in progress, the memory units must be at the middle and lower memory strings 16 completely apply the charging power. In addition, some power is also in the primary voltage level 28 led, so that at the upper storage strand 30 both over the charging station 12 an electric vehicle can be charged, as well as the storage unit 16 can be replenished.

At an in 5 shown situation is connected to only two charging stations an electric vehicle. The lower memory string 30 to which no electric vehicle is connected, the whole of the memory unit 16 taken energy of the primary voltage level 28 make available, so that the memory unit of the upper memory strand 30 can be charged even faster.

Overall, a control device 34 provided the charging station 10 monitors and controls. The control device 34 pursues an energy management, through which the loading strokes of the storage units 16 can be reduced. In that by means of the support modes of the memory strings 30 electrical energy between the storage strings 30 can be replaced, the maximum occurring loading strokes in the storage units 16 be reduced.

In the event that due to the operating time of one of the storage units 16 must be replaced, the operation of the charging station with all charging stations 12 continue to take place as the storage units 16 the remaining memory strings 30 the missing capacity of the storage unit to be replaced 16 can bridge.

Claims (11)

Charging station (10) for electric vehicles with at least two charging stations (12) to each of which an electric vehicle can be charged at the same time, and with an electrical energy store (14), characterized in that the electrical energy store (14) at least two electrically isolated storage units (16 ), that the charging station (10) for each memory unit (16) has a separate bidirectional charge controller (18) that each memory unit (16) is associated with at least one charging station (12) which supplies via the memory unit (16) with electrical energy can be, and that in each case a memory unit (16) of the associated bidirectional charge controller (18) and the at least one associated charging station (12) form a storage string (30). Charging station after Claim 1 characterized in that the memory strings (30) comprise a charging mode of operation in which the memory unit (16) of the memory string (30) is charged, and / or - the memory strings (30) have a power mode of operation in which one or more of the memory strings electrical power is supplied to associated charging columns (12), and / or - that the memory strings (30) have a support mode in which electrical energy is provided via the bidirectional charge controller (18) to supply electrical energy to at least one other storage string (30) , Charging station after Claim 1 or 2 , characterized in that - the charging station (10) has a control device (34) which carries out an energy management, and - that the control device (34) controls the storage strands (30) in such a way that loading strokes of the storage units (16) are reduced. Charging station after Claim 3 characterized in that according to power management, when a power available from a power supply (24) is greater than a total power requested at the charging columns (12), the excess power is used to charge the storage units (16); 16) with the lowest charge level is preferably loaded. Charging station after Claim 3 or 4 characterized in that according to power management, when power available from the power supply (24) is less than a total power requested at the charging posts (12), electric power is provided from the storage units (16), the additional power being preferably from the storage units (16) is provided, the charging stations are active. Charging station after one of the Claims 3 to 5 , characterized in that according to the energy management, when a power available from the power supply (24) is less than a total requested power to the charging columns, and when a charge of one of the storage units (16), the at least one charging station (12) is active , is below a first threshold, at least one memory unit (16) of the other Memory strings (30) provides the missing electrical power. Charging station after one of the Claims 3 to 6 , characterized in that according to the energy management, when the charge levels of two memory units (16) differ from each other by more than a predetermined limit, electric power is supplied from the memory unit (16) having the higher charge level to the memory unit (16). to charge with the lower charge level. Charging station after one of the Claims 1 to 7 characterized in that, when replacing one of the memory units (16), if the power available from the power supply (24) is less than the total power requested at the charging columns (12), at least one storage string (16) provides power to the power supply to provide missing power. Charging station after one of the Claims 1 to 8th , characterized in that the charging station (10) for each charging station (12) has a car charge controller (20) that each such car charge controller (20) has a galvanic isolation. Charging station after one of the Claims 1 to 9 , characterized in that the charging station (10) has a mains connection circuit (22) with galvanic isolation. Charging station after one of the Claims 1 to 10 , characterized in that the charging station (10) per charging station (12) has at least one such storage unit (16).

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