Charging system, charging device and procedure for charging an electric vehicle

Abstract

A charging system for an electric vehicle (10) is described. The charging system comprises a ground unit (1) with a primary coil (11), the primary coil (11) being configured to generate an alternating electromagnetic field. The charging system also includes a receiver unit (2) located outside the electric vehicle (10) with a secondary coil (12), the secondary coil (12) being configured to receive the alternating electromagnetic field of the primary coil (11) for the inductive transfer of electrical energy from the ground unit (1) to the receiver unit (2). A charging cable (5) is connected to the receiver unit (2) for the conductive transfer of electrical energy from the receiver unit (2) to an electrical energy storage device (6) of the electric vehicle (10), the charging cable (5) having a charging plug (4) for connection to a charging socket (3) of the electric vehicle (10).Furthermore, a charging device and a method for charging an electric vehicle are described.

Description

[0001] The invention relates to a charging system and a charging device for an electric vehicle as well as a method for charging an electric vehicle.

[0002] Charging systems for electric vehicles can be implemented conductively or inductively. With conductive charging, electrical energy is transferred from the charging infrastructure to the electric vehicle via a cable. With inductive charging, electrical energy is transferred from a coil on the infrastructure side to a coil on the vehicle side via a magnetic field.

[0003] Conventional conductive charging in public spaces involves charging stations that are quite large, thus taking up valuable space in parking lots or on sidewalks (in the case of on-street charging at the roadside). Furthermore, charging stations make cleaning parking lots and sidewalks more difficult, and the cables between the charging station and the vehicle obstruct passage and can pose a tripping hazard. Charging stations are also increasingly becoming targets of vandalism.

[0004] Inductive charging in public spaces is not yet widespread, as the number of vehicles equipped with this complex technology is increasing only slowly. With inductive charging, the charging efficiency decreases if the air gap between the two coils increases or if the receiver coil is not positioned precisely above the transmitter coil. This necessitates very precise alignment of the vehicle before the charging process.

[0005] In inductive charging, the charging efficiency is significantly influenced by the horizontal and vertical alignment of the infrastructure-side primary coil relative to the vehicle-side secondary coil. For example, German patent DE 10 2014 222 000 A1 discloses a method for inductively charging electric vehicles in which energy is transferred from a primary coil located in a ground unit to a secondary coil located in the vehicle. A movable primary coil in the ground unit is described to optimize the coupling between the primary and secondary coils. Furthermore, German patent DE 10 2012 217 779 A1 discloses that the transferable charging power in inductive charging is highly dependent on the distance between the charging station-side and vehicle-side coil systems. It is proposed to optimize this distance using a chassis control unit.

[0006] It is an object of the invention to provide an improved charging system, a charging device, and a method for charging an electric vehicle. The charging system, the charging device, and the method are intended, in particular, to overcome the disadvantages of conductive and inductive charging described above.

[0007] This problem is solved by a charging system, a charging device, and a method for charging an electric vehicle according to the independent claims. Advantageous embodiments and further developments of the invention are described in the dependent claims.

[0008] According to one embodiment, the charging system for an electric vehicle comprises a ground unit with a primary coil, the primary coil being configured to generate an alternating electromagnetic field. For the purposes of this text, an electric vehicle is understood to be a motor vehicle that is at least partially electrically powered, for example, a battery electric vehicle (BEV) or a plug-in hybrid electric vehicle (PHEV). The term "electric vehicle" does not preclude the possibility that the electric vehicle may also have an internal combustion engine in addition to an electric motor. The alternating electromagnetic field generated by the primary coil of the ground unit can advantageously have a frequency that corresponds to a cross-manufacturer standard for the inductive charging of electric vehicles, so that the charging system is applicable to electric vehicles from various manufacturers. For example, the alternating electromagnetic field can have a frequency of approximately 85 kHz.

[0009] Furthermore, the charging system features a receiver unit with a secondary coil located outside the electric vehicle. The secondary coil is configured to receive the alternating electromagnetic field of the primary coil for the inductive transfer of electrical energy from the ground unit to the receiver unit. The receiver unit is not an integral part of the electric vehicle, nor is it permanently attached to it. Rather, the receiver unit is portable and can, for example, be carried in the electric vehicle by its user for use outside the vehicle when needed.

[0010] Furthermore, the charging system includes a charging cable connected to the receiver unit for the conductive transfer of electrical energy from the receiver unit to the electric vehicle's electrical energy storage device. The electrical energy storage device is, in particular, a high-voltage battery, which, for example, has a voltage of approximately 400 V or 800 V. The electrical energy storage device could, for instance, be a lithium-ion battery containing a large number of lithium-ion battery cells. The charging cable has a charging plug for connection to the electric vehicle's charging socket. Advantageously, the charging plug and the charging socket conform to an international, national, or regional standard, allowing the receiver unit to be connected to electric vehicles from various manufacturers via the charging cable.For example, the charging plug and socket can conform to the CCS (Combined Charging System) standard widely used in Europe or be designed according to another country-specific standard. In the charging system described here, the transfer of electrical energy from the receiving unit to the electric vehicle's electrical energy storage system is conductive via the charging cable.

[0011] The invention is based in particular on the considerations set out below: In the charging system described here, the charging energy is supplied from a ground-level unit, which can be located entirely below the surface of a traffic area such as a road, a sidewalk, or a parking lot. A charging point for the electric vehicle can therefore be free of a charging station, which would otherwise require space in the public traffic area and could be an obstacle, especially for pedestrians, cyclists, or snow removal vehicles. This facilitates the cleaning of parking lots or sidewalks. Since the receiving unit can advantageously be connected to a charging socket of the electric vehicle via a charging cable, the possibility of inductive charging can be made available for existing vehicles that do not have an integrated secondary coil for inductive charging.The receiver unit with the charging cable can be advantageously offered as an accessory for conventional electric vehicles that are equipped for conductive charging via a charging socket.

[0012] In one embodiment, the ground unit is installed flush with the surface of a traffic area, which could be, for example, a street, a sidewalk, or a parking lot. In other words, the ground unit does not protrude above the surface of the traffic area and therefore does not pose an obstacle to road users. Advantageously, the receiving unit is only temporarily positioned on the ground unit during the charging process, so that the traffic area remains freely available otherwise.

[0013] With this charging system, the receiver unit can advantageously be positioned directly on the base unit. This advantage arises particularly from the fact that the receiver unit is not permanently installed in the electric vehicle and can be positioned directly on the base unit by the user. This makes it possible, in particular, to eliminate any air gap or maintain a defined, advantageous air gap between the primary and secondary coils. This increases charging efficiency and eliminates the risk of living beings being present between the primary and secondary coils during the charging process.

[0014] According to one embodiment, the base unit and / or the receiver unit have a magnetic or mechanical fixing device for alignment on the base unit. For example, mechanical fixing can be achieved by an easily detachable connection such as a bayonet fitting. It is also possible that the base unit and the receiver unit each have magnets that can align and fix the receiver unit in a predetermined position on the base unit.

[0015] In one embodiment, the receiving unit includes an electrical converter for generating a charging current. The electrical converter can, in particular, be an AC / DC converter that converts an alternating current inductively generated in the secondary coil into a direct current, which is transmitted to the electric vehicle via the charging cable.

[0016] The invention further relates to a charging device for an electric vehicle, comprising the receiver unit described above and the charging cable connected to the receiver unit. The receiver unit includes a secondary coil configured to receive the alternating electromagnetic field of a primary coil for the inductive transfer of electrical energy from a ground unit to the receiver unit. The charging cable includes a charging plug for connecting to a charging socket of the electric vehicle in order to conductively transfer electrical energy from the receiver unit to an electrical energy storage device of the electric vehicle. The charging cable can, in particular, be permanently connected to the receiver unit. The charging device comprising the receiver unit and the charging cable can be an accessory for the electric vehicle that can be purchased separately from the vehicle.

[0017] According to one embodiment, the charging device is configured to transmit an electrical power of at least 3 kW, particularly in the range of 3 kW up to and including 11 kW, or even up to and including 22 kW. For example, the charging device can be configured to transmit an electrical power of approximately 3.7 kW, approximately 7.4 kW, or approximately 11 kW. This corresponds to the typical electrical powers achieved with conventional single-phase, two-phase, or three-phase conductive AC charging at a current of approximately 16 A. The charging device described here thus represents, in terms of its potential charging power, a significant alternative to conventional conductive AC charging. Since the achievable charging power scales with the size and weight of the secondary coil, a compromise between charging power and weight is advantageously sought, ensuring that the receiving unit is easy for the user to handle.

[0018] The invention further relates to a method for charging an electric vehicle, in which an alternating electromagnetic field is generated in a primary coil of a ground unit, wherein the alternating electromagnetic field of the primary coil is received by a secondary coil in a receiving unit for the transmission of electrical energy from the ground unit to the receiving unit, the receiving unit being arranged outside the electric vehicle. The electrical energy is transmitted by means of a charging cable which has a charging plug for connection to a charging socket of the electric vehicle.

[0019] In this method, the receiving unit is advantageously positioned directly on the base unit, so that, in particular, no air gap remains. The receiving unit is, for example, carried in the electric vehicle by the user and placed on the base unit before charging. The receiving unit, including the secondary coil, can weigh, for example, between approximately 3 kg and 8 kg and can therefore be easily removed from the vehicle by the user and positioned on a base unit, for example, directly next to the vehicle. Precise positioning of the receiving unit on the base unit can be facilitated for the user by a previously described mechanical or magnetic fixing device.

[0020] The optional configurations described in connection with the charging system, the charging device and the method apply across the board to the charging system, the charging device and the method.

[0021] The following describes an embodiment of the invention with reference to the accompanying drawings. Further details, preferred embodiments, and further developments of the invention will be derived from these drawings. Specifically, the drawings schematically illustrate... Fig. 1 a charging system for an electric vehicle according to an exemplary embodiment, and Fig. 2 a charging device for an electric vehicle according to an initial example.

[0022] Identical or similarly functioning components are marked with the same reference symbols in the figures. The depicted components and their relative sizes are not to scale; rather, individual components, such as the ground unit and receiving unit, are exaggerated for clarity.

[0023] In Fig. Figure 1 shows an electric vehicle 10 during a charging process. The electric vehicle 10 can be, in particular, a battery electric vehicle (BEV) or a plug-in hybrid electric vehicle (PHEV). The electric vehicle 10 has an electrical energy storage device 6, which is, in particular, a so-called high-voltage battery. The high-voltage battery can, for example, have a voltage of approximately 400 V or approximately 800 V. In particular, the electrical energy storage device 6 can be a lithium-ion battery comprising a plurality of lithium-ion battery cells. The electrical energy storage device 6 is intended to provide energy for driving an electric motor of the electric vehicle 10; that is, the electrical energy storage device 6 is a traction battery of the electric vehicle 10.

[0024] For charging the electrical energy storage device 6, the electric vehicle 10 has a charging socket 3. In the charging process shown, a charging cable 5 with a charging plug 4 is connected to the charging socket 3. The charging cable 5 is enclosed in a receiving unit 2 located outside the electric vehicle 10, which receives electrical energy from a ground unit 1 by inductive energy transfer to generate the charging current.

[0025] The ground unit 1 is preferably arranged flush with the surface of a traffic area 15, wherein the traffic area 15 is, for example, a parking lot or a sidewalk located next to a road or parking lot. Since the ground unit 1 is advantageously arranged flush with the surface of the traffic area 15, no traffic space is lost when the ground unit 1 is not in use, unlike, for example, a charging station. The ground unit 1 contains a primary coil 11 for generating an alternating electromagnetic field. The ground unit 1 can be supplied with power, for example, by underground cables.

[0026] The receiving unit 2 contains a secondary coil 12, which receives the alternating electromagnetic field of the primary coil 11 for inductive energy transfer from the base unit 1 to the receiving unit 2. The receiving unit 2 is a mobile unit that is not permanently installed on the electric vehicle 10 and is, for example, placed on the base unit 1 by the user of the electric vehicle 10 before the charging process. The receiving unit 2 is placed directly on the base unit 1, preferably so that no air gap remains between the base unit 1 and the receiving unit 2. In this way, the distance between the primary coil 11 and the secondary coil 12 can be kept small during inductive energy transfer, thus achieving high efficiency of the inductive energy transfer.To facilitate optimal positioning of the receiver unit 2 on the base unit 1 and to secure the receiver unit 2 to the base unit 1 during the charging process, the base unit 1 and the receiver unit 2 can each have a magnetic and / or mechanical fixing device 13, 14. For example, the base unit 1 has magnets 13 and the receiver unit 2 has corresponding opposite-polarity magnets 14, which allow a user to easily position and fix the receiver unit 2 to the base unit 1. Alternatively or additionally, mechanical devices can be provided that, for example, cause the receiver unit 2 to snap into the correct position on the base unit 2.

[0027] The receiving unit 2 can contain an electrical converter 7 to generate a charging current from the received electrical energy. The electrical converter 7 can, in particular, be an AC / DC converter that generates a direct current, which is transmitted to the electric vehicle 10 via the charging cable 5 and the charging plug 4. The charging plug 4 and the corresponding charging socket 3 are advantageously configured to transmit a direct current. For example, the charging plug 4 and the charging socket 3 can be designed according to the CCS (Combined Charging System) standard and are therefore suitable for transmitting both alternating current and direct current. Alternatively, the charging socket 3 and the charging plug 4 can also be designed according to other standards, in particular regional or country-specific standards.

[0028] The ground unit 1 can accommodate a control unit 8, which can advantageously communicate with a control unit 9 of the electric vehicle 10, in particular via WLAN or another data communication technology. The data communication can, in particular, include the exchange of vehicle and / or user data to authorize and / or bill the charging process. The ground unit 1 can, for example, be installed in a public space and operated by a charging network operator, similar to a charging station.

[0029] In Fig.Figure 2 shows a charging device for an electric vehicle, which is formed by the previously described receiver unit 2 comprising the secondary coil 12, the electrical converter 7, and an optional fixing device 14, as well as the charging cable 5 and the charging plug 4. Such a charging device can, for example, be offered as a separate accessory for the electric vehicle 10 and can, for example, be carried by the user in the electric vehicle 10 for use when needed. When used for a charging process, the receiver unit 2 is placed on a suitable base 1 and connected to the charging socket 3 of the electric vehicle 10 via the charging cable 5 and the charging plug 4. This charging device makes it possible to apply the principle of inductive charging even to electric vehicles 10 that are not equipped with a secondary coil installed in the electric vehicle 10.This will also enable existing vehicles to use charging points designed for inductive charging.

[0030] Although the invention has been illustrated and described in detail with reference to exemplary embodiments, the invention is not limited by these embodiments. Rather, other variations of the invention can be derived by a person skilled in the art without departing from the scope of protection of the invention as defined by the claims. Reference symbol list 1 floor unit 2 receiver units 3 charging sockets 4 charging plugs 5 charging cables 6 electrical energy storage 7 AC / DC converters 8 Control unit in the floor unit 9 Control unit in the vehicle 10 electric vehicles 11 Primary coil 12 Secondary coil 13 Fixing device 14 Fixing device 15 traffic area QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2014 222 000 A1

[0005] DE 10 2012 217 779 A1

[0005]

Claims

[1] Charging system for an electric vehicle (10), comprising - a ground unit (1) with a primary coil (11), wherein the primary coil (11) is configured to generate an alternating electromagnetic field, - a receiving unit (2) arranged outside the electric vehicle (10) with a secondary coil (12), wherein the secondary coil (12) is configured to receive the alternating electromagnetic field of the primary coil (11) for inductive transfer of electrical energy from the ground unit (1) to the receiving unit (2), and - a charging cable (5) connected to the receiving unit (2) for the conductive transfer of electrical energy from the receiving unit (2) to an electrical energy storage device (6) of the electric vehicle (10), wherein the charging cable (5) has a charging plug (4) for connection to a charging socket (3) of the electric vehicle (10). [2] Charging system according to claim 1, wherein the floor unit (1) is installed flush with a traffic area (15). [3] Charging system according to one of the preceding claims, wherein the receiving unit (2) can be arranged directly on the ground unit (1). [4] Charging system according to one of the preceding claims, wherein the base unit (1) and / or the receiving unit (2) have a magnetic or mechanical fixing device (13, 14). [5] Charging system according to one of the preceding claims, wherein the receiving unit (2) comprises an electrical converter (7) for generating a charging current. [6] Charging device for an electric vehicle, comprising - a receiving unit (2) with a secondary coil (12), wherein the secondary coil (12) is configured to receive the alternating electromagnetic field of a primary coil (11) for inductive transmission of electrical energy, and - a charging cable (5) connected to the receiving unit (2), which has a charging plug (4) for connection to a charging socket (3) of the electric vehicle (10), for conductive transmission of electrical energy from the receiving unit (2) to an electrical energy storage device (6) of the electric vehicle (10). [7] Charging device according to claim 6, wherein the charging device is configured to transmit an electrical power of at least 3 kW. [8] Method for charging an electric vehicle (10), comprising the steps - Generating an alternating electromagnetic field in a primary coil (11) of a ground unit (1), - Receiving the alternating electromagnetic field of the primary coil (11) with a secondary coil (12) in a receiving unit (2) for the transmission of electrical energy from the ground unit (1) to the receiving unit (2), wherein the receiving unit (2) is arranged outside the electric vehicle (2), and - conductive transmission of electrical energy from the receiving unit (2) to an electrical energy storage device of the electric vehicle (10) using a charging cable (5) which has a charging plug (4) for connection to a charging socket (3) of the electric vehicle (10). [9] Method according to claim 8, wherein the receiving unit (2) is arranged directly on the ground unit (1). [10] Method according to one of claims 8 or 9, wherein the receiving unit (2) is aligned on the ground unit (1) by a magnetic or mechanical fixing device (13, 14).

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