DE102013217713A1 - Inductive power transmission coil, charging station, method of positioning an inductive power transmission device, and method of detecting a foreign object between a transmission coil and a reception coil - Google Patents

Abstract

The present invention provides a transmitting coil for inductive power transmission to a receiving coil spaced from the transmitting coil, having one or more coil windings arranged in a coil plane; and a pattern plate which is disposed in a plane above the coil plane and on which an optical contrast pattern is applied. The invention further provides methods of positioning an inductive power transfer device and detecting a foreign object between a transmitting coil and a receiving coil of an inductive power transmitting device, each of which makes use of such a transmitting coil.

Description

The present invention relates to a transmitting coil for inductive energy transmission from the transmitting coil to a receiving coil spaced from the transmitting coil, a charging station with such a transmitting coil, a method for positioning an inductive energy transfer device, in particular for positioning a receiving coil with respect to a transmitting coil of an inductive energy transfer device, and a method of detecting a foreign object between a transmitting coil and a receiving coil.

State of the art

Electric vehicles usually have an electrical energy storage, such as a traction battery that provides the electrical energy for propulsion. If this electrical energy store is completely or partially discharged, then the electric vehicle has to control a charging station, at which the energy store can be recharged. So far, it is customary for this purpose that the electric vehicle is connected to the charging station by means of a cable connection at such a charging station. This connection must usually be made manually by a user. It is also necessary that charging station and electric vehicle have a mutually corresponding connection system.

There are also known wireless charging systems for electric vehicles. For this purpose, an electric vehicle is placed over a coil. This coil emits a magnetic alternating field. The alternating magnetic field is absorbed by a receiving coil within the vehicle and converted into electrical energy. By means of this electrical energy, a traction battery of the vehicle can then be charged. The publication DE 10 2011 010 049 A1 discloses such a system for charging a vehicle battery, in which the energy is transmitted inductively.

Often the receiving coils are in electric vehicles for reasons of improved accident safety and the increased protection against the weather in the underbody of the vehicle. When wirelessly charging a battery of the electric vehicle is therefore located between the recessed in the bottom of a charging station transmitting coil of the charging station and the receiving coil in the vehicle, an air gap. Due to the required ground clearance of motor vehicles, this air gap is a few centimeters. Air gaps in the size of 15-25 cm are very common, unless an ideal small air gap is achieved by measures such as lowering the vehicle-fixed coil, the entire vehicle or lifting the stationary coil or a combination of these measures. Due to the strong magnetic fields, however, it is not desirable for objects such as contaminants or animals to be in the air gap during the charging process.

In addition, the efficiency of the energy transfer between the transmitting coil and the receiving coil depends strongly on the relative position of the (mobile) receiving coil in the vehicle with respect to the (fixedly mounted) transmitting coil in a charging station. The efficiency depends on the coupling factor of the coils with each other or on the size of the magnetic stray field.

The publication WO 2012/058466 A1 discloses a coil positioning of a vehicle-mounted power transmission device by a mechanical positioning device in the base of the vehicle. The publication JP 2011 217 452 A discloses a positioning of receiver coils of an inductive power transmission device in the license plate area of vehicles. The publication CN 201 966 671 U discloses a positioning of receiver coils of an inductive power transmission device on the vehicle roof. The publication US 2012/0098483 A1 discloses a position determination and an automatic parking function using in-vehicle antennas for navigating the vehicle to a loading position with respect to an inductive power transmission device. The pamphlets DE 10 2010 053 058 A1 . JP 2012 005 308 . DE 10 2009 033 239 A1 and DE 10 2009 033 237 A1 each disclose additional positioning coils in vehicles to increase the positioning tolerance to inductive power transmission devices.

However, there is a need for solutions for inductive energy transfer, on the one hand reliably detect an object in the transmission range of the inductive energy transmission path and on the other hand can improve the positioning of the transmitting and receiving coil relative to each other.

Disclosure of the invention

The present invention provides, in one aspect, a transmit coil for inductive power transfer to a receive coil spaced from the transmit coil, having one or more coil windings disposed in a coil plane; and a pattern plate which is disposed in a plane above the coil plane and on which an optical contrast pattern is applied.

According to a further aspect, the present invention provides a charging station for inductive energy transmission to a motor vehicle, with a transmitting coil according to the invention, the coil plane is arranged horizontally in the bottom of the charging station, and a coil control device which is connectable to a power network, and which is designed to Supplying coil with electric current.

In yet another aspect, the present invention provides a method of positioning an inductive energy transfer device, comprising the steps of detecting an optical contrast pattern applied to a pattern plate in a plane above the coil plane of a stationary transmit coil of an inductive energy transfer device using at least one optical detector of a vehicle having a receiving coil for inductive energy transmission from the transmitting coil, the driving of an automatic parking assistance system of the vehicle on the basis of one of the detected optical contrast pattern dependent detection signal of the at least one optical detection device, and the automatic parking of the vehicle using the automatic parking assistance system, so that the receiving coil is positioned for inductive energy transmission relative to the transmitting coil.

In yet another aspect, the present invention provides a method of detecting a foreign object between a transmitting coil and a receiving coil of an inductive power transmitting device, comprising the steps of detecting a contrast optical pattern formed on a pattern plate in a plane above the coil plane of a stationary transmitting coil of an inductive power transmitting device is applied, by means of at least one optical detection device of a vehicle having a receiving coil for inductive energy transmission from the transmitting coil, comparing the detected optical contrast pattern with a reference pattern, and determining that a foreign object between the transmitting coil and the receiving coil is located, if detected optical contrast pattern relative to the reference pattern has a deviation lying above a detection threshold.

It is an idea of the present invention to provide a transmission coil with an optically detectable pattern, so that optical detection devices of a vehicle can perform an automatic vehicle positioning via pattern recognition. Moreover, after positioning, the optically detectable pattern can be used to detect foreign objects above the transmitting coil, which completely or partially shield the pattern from cameras of the vehicle, so that foreign objects can be detected by comparison with a reference pattern.

An essential advantage of the present invention is that the positioning of the transmitting and receiving coils relative to each other can be significantly improved without having to provide additional elements or components in the vehicle. For example, already existing systems such as parking assistance systems with associated parking assistance cameras of the vehicle can be used to perform the coil positioning can. This enables a very cost-effective implementation of a positioning system for inductive power transmission devices in vehicles.

In addition, the comfort for the vehicle driver is increased, which can save time by the accelerated parking operation and on the other hand costs by the improved charging efficiency by the automatic positioning of the vehicle over the transmitting coil on the one hand.

Additional sensor systems can also be saved, which eliminates additional disturbing influences on the electromagnetic compatibility of the inductive energy transfer device. In addition, the positioning and foreign object detection methods are reliable, fast and efficient.

According to an embodiment of the transmit coil, the optical contrast pattern may comprise a periodic tile pattern of brightness contrasted geometric shapes. Alternatively or additionally, the optical contrast pattern may comprise a periodic lattice structure of lines contrasted in brightness. In this case, according to a further embodiment, it may be provided that the optical contrast pattern has lines or shapes of different thickness or extent. Depending on the parking situation of the charging station, the different types and types of contrast patterns can be made differently fine or coarse in order to optimize the positioning accuracy of the vehicle.

According to an embodiment of the charging station, the charging station may further comprise a communication device which is coupled to the coil control device and which is designed to transmit a position and / or identification radio signal wirelessly. In this case, according to a further embodiment, the communication device can furthermore be designed to emit a reference radio signal via the geometric nature of the optical contrast pattern of the sample plate. This allows it in a simple way to tell the vehicle in advance information about the positioning of the vehicle on the special charging station, without the vehicle needs to know the details of the charging station and in particular the pattern on the transmitting coil in advance.

Further features and advantages of embodiments of the invention will become apparent from the following description with reference to the accompanying drawings.

Brief description of the drawings

Show it:

1 a schematic representation of a plan view of a vehicle with an inductive power transmission device in the vicinity of a charging station according to an embodiment of the invention;

2 a schematic representation of a cross-sectional view of an inductive power transmission device according to another embodiment of the invention;

3 a schematic representation of a transmitting coil with a pattern plate according to another embodiment of the invention;

4 a schematic representation of another transmitting coil with a pattern plate according to another embodiment of the invention;

5 a schematic representation of yet another transmitting coil with a pattern plate according to another embodiment of the invention;

6 a schematic representation of an optical monitoring of a transmitting coil according to another embodiment of the invention;

7 a schematic representation of a method for positioning an inductive power transmission device according to another embodiment of the invention; and

8th a schematic representation of a method for detecting a foreign object between a transmitting coil and a receiving coil of an inductive power transmission device according to another embodiment of the invention.

The drawings shown in the figures are partly perspective views of elements that are not necessarily drawn to scale for the sake of clarity. Like reference numerals generally designate like or equivalent components.

1 shows a vehicle 20 that over an inductive charging station 100 can be turned off or should. The vehicle 20 may in particular be an electrically operable vehicle, such as an electric car, a hybrid vehicle or other vehicle with an electric and rechargeable energy storage. The vehicle 20 includes a receiver coil 21 which, for example, in an underbody of the vehicle 20 is arranged so that the coil plane is parallel to the ground or driving surface.

The vehicle 20 is for inductive energy transfer via a transmitting coil 10 the charging station 100 so turn off the receiver coil 21 of the vehicle 20 above the transmitting coil 10 is arranged. When the transmission coil 10 in the bottom of the charging station 100 is arranged, it is due to the required ground clearance of the vehicle 20 required that between the transmitter coil 10 and the bottom of the vehicle 20 in which the receiver coil 21 is located, a gap with an air gap.

After the vehicle 20 so turned off that the receiving coil 21 in the vehicle 20 above the transmitter coil 10 can, charging the electrical energy storage of the vehicle 20 , For example, a traction battery begin. For this purpose, the transmission coil generates 10 a magnetic alternating field. This alternating magnetic field is from the receiving coil 21 absorbed and converted into electrical energy. The electrical energy is then via a suitable circuit for charging the electrical energy storage of the vehicle 20 to disposal.

For a return of electrical energy from the vehicle 20 in a power supply network can also reverse the coil 21 in the vehicle 20 serve as a transmitting coil that generates a magnetic field. The sink 10 in the charging station 100 then operates as a receiving coil, which receives the energy of the magnetic field and converts it into electrical energy, which can then be fed into a power grid.

Is now the vehicle 20 with the receiver coil 21 at the charging station 100 above the transmitting coil 10 turned off, so the charging of the electrical energy storage can be started. For this purpose, if necessary, initially a data connection between the vehicle 20 and the charging station 100 built up. Such a data connection may preferably be a wireless connection. For example, the connection can be made optically, for example on the basis of infrared light, by means of a radio connection, such as WLAN, GSM, Bluetooth, etc., or by means of an inductive connection between the vehicle 20 and charging station 100 , By such a data connection can first an authorization of the vehicle 20 and / or the driver. Furthermore, the exchange of vehicle-specific parameters and the transmission of parameters for a later billing of the costs are possible.

Exemplary is in 1 this one of the charging station 100 associated communication device 12 shown communicating via radio communication with a vehicle communication device 23 can communicate and thereby position and / or identification radio signals RF to the vehicle communication device 23 can transmit. For example, the position and / or identification radio signals RF may serve to extend beyond a threshold distance D, for example 2 meters to 10 meters, from the charging station 100 remote vehicle 20 about the location of the charging station 100 to inform so that the driver of the vehicle 20 is able to move to the charging station by manual driving 100 to approach.

When the vehicle 20 closer than the threshold distance D to the charging station 100 It is envisaged that optical detection devices 22 of the vehicle, for example parking assist cameras (so-called "near real cameras", NRCs), can be used to drive the vehicle 20 automatically park using a parking assistance system. It can be like in 1 shown, six optical detection devices 22 around the body of the vehicle 20 be arranged around. It should be understood, however, that the number and position of the optical detectors 22 at the vehicle 20 can vary. The optical detection devices 22 For example, parking marks 16 the charging station 100 use, for example, on the floor applied colored or different colored lines or borders, to provide the parking assistance system with drive signals. This can be done by triangulation via corresponding distance or angle measurements M of different detection devices 22 opposite the respective parking markings 16 respectively. The parking assistance system can also be equipped with steering wheel and speed control of the vehicle 20 be connected to appropriate steering and driving operations on the vehicle 20 to be able to make automatically. The parking assistance system can be the driver of the vehicle 20 inform about a possible automatic positioning, which the driver can initiate with a corresponding control command.

The optical detection devices 22 Furthermore, an optical contrast pattern, which on a pattern plate of the transmitting coil 10 is applied, record and evaluate.

A detailed view of the inductive energy transfer device with the in the vehicle floor 24 arranged receiving coil 21 as well as arranged in the bottom of the charging station transmitting coil 10 is in 2 shown. The vehicle floor 24 can in particular a as in 1 illustrated vehicle 20 and the transmitting coil 10 especially one like in 1 illustrated charging station 100 be assigned.

The transmitting coil 10 is via a control circuit 14 with a power supply network 15a . 15b coupled. The control circuit 14 is for communication with the vehicle with the communication device 12 connected. The communication device 12 also has an antenna 13 for wireless communication with the vehicle communication device 23 on, in turn, a corresponding antenna 27 having.

The receiver coil 21 is in turn with a charging circuit 25 in the vehicle 20 connected to the vehicle communication device 23 is coupled. The charging circuit 25 can also have a suitable control device, the charging processes and the energy transfer between the transmitting coil 10 and the receiving coil 21 monitors and controls.

Optimal positioning of the receiver coil 21 above the transmitting coil 10 requires a relatively accurate positioning in a positioning region R, in which the electrical coil parameters such as inductance, quality, resistance, resonance frequency ensure the highest possible coupling factor between the coils. In order to achieve the positioning region R as accurately as possible, is on the transmission coil 10 a sample plate 11 applied. The transmitting coil 10 itself may have one or more coil windings, which are arranged in a coil plane. The pattern plate 11 can then be arranged in a plane above the coil plane. The pattern plate 11 For example, it may comprise a transparent plate, a plastic adhesive sheet, or other suitable cover for the transmitting coil windings.

On the pattern plate 11 is applied an optical contrast pattern. Exemplary embodiments for the optical contrast pattern are in the 3 to 5 illustrated. The sample plates 11 For example, each may have a coarse contrast pattern with coarse or thick lines surrounding the transmitting coil surfaces. In addition, the coarse line structure may have a positioning cross, which may mark a center of the transmitting coil surface.

Furthermore, the optical contrast pattern can be finer beyond the coarse contrast pattern Have contrasting patterns of finer lines or shapes. For example, the optical contrast pattern may have a periodic lattice structure of lines contrasted in brightness. This lattice structure may have different lattice directions, as with the pattern examples 11a and 11b indicated. In addition, the optical contrast pattern can also be a periodic tile pattern 11c having contrasted in the form of geometric shapes. Overall, the optical contrast pattern may comprise lines or shapes of varying thickness or extent, wherein the lines or shapes of line width or shape extent above a particular first threshold may be attributed to the coarse contrast pattern and lines or shapes of line width or shape extent below a particular second threshold value to the fine contrast pattern ,

The rough contrast pattern can, for example, for the approach of the vehicle 20 to the transmitting coil 10 be used because the rough lines of the detection devices 22 could be recognized and resolved at a greater distance. The fine contrast patterns can then on the one hand for a fine adjustment of the vehicle position on the transmission coil 10 be used when the receiving coil 21 already near the ideal positioning range R is located. On the other hand, the fine contrast pattern can also be used for a Fremdobjekterkennung, as in connection with the 6 and 8th explained in more detail below.

The communication device 12 For example, it may be configured to provide a reference radio signal on the geometric nature of the optical contrast pattern of the respective pattern plate used in the loading station 11 so that the charging station approaching vehicles are informed about the type of optical contrast pattern and the detection devices 22 or configure the parking assistance system accordingly.

7 shows a schematic representation of a method 30 for positioning an inductive energy transfer device, such as in connection with the 1 to 5 explained. The procedure 30 includes as a first step 31 detecting a contrast optical pattern 11a . 11b . 11c which is on a pattern plate 11 in a plane above the coil plane of a stationary transmission coil 10 the inductive energy transmission device is applied, using at least one optical detection device 22 of a vehicle 20 which is a receiving coil 21 for inductive energy transfer from the transmitting coil 10 having. As a second step 32 can be an automatic parking assistance system of the vehicle 20 based on one of the detected optical contrast pattern 11a . 11b . 11c dependent detection signal of the at least one optical detection device 22 be controlled, so that in one step 33 an automatic parking of the vehicle 20 can be done using the automatic parking assistance system. This allows the receiver coil 21 for inductive energy transmission relative to the transmitting coil 10 be optimally positioned.

For optimal positioning, it may additionally be provided to measure or evaluate additional electrical coil parameters such as inductance, quality, resistance or resonance frequency during the parking process and to incorporate them into the adjustment of the parking assistance system. This can be done in particular by the fact that the charging station 100 at the approach of the vehicle 20 via a corresponding approach signal, which via the vehicle communication device 23 to the communication device 14 the charging station 100 is transferred, is placed in a standby mode, in which by the transmitting coil 10 For example, a magnetic field of lesser strength is generated. By measuring this magnetic field and the corresponding evaluation of the coil parameters of the receiver coil 21 in the vehicle 20 can be positioning over the captured optical contrast pattern 11a . 11b . 11c get supported.

The size of the gap between a transmitter coil 10 and a receiving coil 21 an inductive energy transfer device, as in connection with the 1 to 5 shown, can be several centimeters. In typical vehicle types today, air gaps between 15 and 25 cm are to be expected. But other sizes for the space between the charging station floor and vehicle underside are also possible. This gap is usually freely accessible. Therefore, there is a possibility that living things or objects may invade at any time in this space. For example, animals, such as cats or mice, can invade. Further, there is also the danger that due to external influences objects, such as dirt, debris, leaves or the like, can penetrate into this space. In particular, flammable, metal-containing objects pose a great danger during the inductive charging process, since these objects heat up strongly and can then ignite if necessary.

To during the inductive energy transfer from the transmitting coil 10 to the receiving coil 21 To ensure that there are no unwanted objects in the gap, this gap is from an optical detection device 26 monitored, for example, in the subsoil 24 of the vehicle 20 be attached can, as related to 6 exemplified. The optical detection device 26 may be, for example, a camera or an optical sensor.

In the present case, an inductive energy transfer from a charging station 100 to an electric vehicle 20 are the elements of the optical detection device 26 very strongly exposed to environmental influences. Therefore, for example, dust or whirled up dirt may cause contamination of the optical detection device 26 come. In this case would be a reliable monitoring of the gap between the transmitting coil 10 and receiver coil 21 not possible anymore. Therefore, furthermore, a cleaning device may be provided which comprises the elements of the optical detection device 26 cleans and thus freed of impurities. For example, such a cleaning device, the elements of the optical detection device 26 clean with a water jet. For this purpose, the cleaning device may have one or more nozzles, from which water is emitted with a suitable pressure. Such a cleaning device may comprise, for example, a tank for a cleaning liquid, such as water, a pump and one or more nozzles. Further possibilities for cleaning the optical detection device 26 such as mechanical wiper blades, air jets or other suitable means are also possible.

For cleaning the optical monitoring device, it is possible, for example, that the optical detection device 26 at the vehicle 20 already cleaned while driving. Thus stands the optical detection device 26 when parking the vehicle 20 immediately available and can be used immediately. Alternatively, it is also possible to use the optical detection device 26 only when parking the vehicle 20 , or to clean only when initiating the charging process.

By the optical detection device 26 can be checked before charging, whether the space between the transmitter coil 10 and receiver coil 21 is free of foreign objects. Detects the optical detection device 26 doing so that there is an undesirable object or animal in the space, so the charging process is not started.

Will during this charging by the optical detection device 26 detected that a foreign object in the space between the transmitter coil 10 and receiver coil 21 penetrates, so the optical detection device 26 first give a warning signal. If the intermediate space is subsequently freed from the detected object within a predetermined time, the charging process is continued without interruption. For example, it is therefore conceivable that an invaded animal is frightened by the warning signal and then leaves the gap again. Another possibility is, for example, that a nearby user can immediately remove the penetrating object when the warning signal sounds, before major damage occurs.

If, on the other hand, the detected object is not removed from the intermediate space within a predetermined period of time, then the charging process is interrupted by the transmission coil 10 is deactivated. Thus it can be prevented that caused by the penetrated object greater damage.

Alternatively, it is also possible, in the detection of a penetrating object immediately the transmitting coil 10 to disable and stop the charging process. Also with the immediate shutdown of the charging process and the deactivation of the transmitting coil 10 Optionally, a suitable warning signal can be output.

Furthermore, the optical detection device 26 also be coupled with an additional notification device (not shown) which sends a notification to a user upon detection of an object in the space. For example, this may be a notification of the user via a mobile telephone connection or the sending of a message via a suitable further radio connection. Thus, even then, the user can know about the intrusion of an object in the gap detection device 26 be informed if he is not in the immediate vicinity of the vehicle 20 staying. Since the charging process of an electric vehicle can usually take several hours, it is possible that the user is also at a remote location during this time. By means of a previously described notification by means of a radio signal, the user can also be formed in these cases via an occurring fault. The user can then come to his vehicle, eliminate the fault and then resume charging.

8th shows a schematic representation of a method 40 for detecting a foreign object F between a transmitting coil 10 and a receiving coil 21 an inductive energy transfer device. In a first step, an optical contrast pattern, which is on a pattern plate 11 in a plane above the coil plane of a stationary transmission coil 10 an inductive energy transfer device is applied, using at least one optical detection device 26 of a vehicle 20 which is a receiving coil 21 for inductive energy transfer from the transmitting coil 10 has to be detected. Here, for example, in connection with the 1 to 5 illustrated transmission coil 10 be used.

In a second step, the detected optical contrast pattern is compared with a reference pattern, which is for example in the optical detection device 26 can be stored. In a third step 43 can then be found that a foreign object F between the transmitting coil 10 and the receiving coil 21 is located, if the detected optical contrast pattern with respect to the reference pattern has a deviation lying above a detection threshold.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102011010049 A1 [0003]
• WO 2012/058466 A1 [0006]
• JP 2011217452 [0006]
• CN 201966671 U [0006]
• US 2012/0098483 A1 [0006]
• DE 102010053058 A1 [0006]
• JP 2012005308 [0006]
• DE 102009033239 A1 [0006]
• DE 102009033237 A1 [0006]

Claims (9)

Transmitting coil ( 10 ) for inductive energy transmission to one of the transmitting coil ( 10 ) spaced receiving coil ( 21 ), comprising: one or more coil windings arranged in a coil plane; and a pattern plate ( 11 ), which is arranged in a plane above the coil plane, and on which an optical contrast pattern ( 11a ; 11b ; 11c ) is applied. Transmitting coil ( 10 ) according to claim 1, wherein the optical contrast pattern ( 11a ; 11b ; 11c ) has a periodic tile pattern of brightness contrasted geometric shapes. Transmitting coil ( 10 ) according to claim 1, wherein the optical contrast pattern ( 11a ; 11b ; 11c ) has a periodic lattice structure of lines contrasted in brightness. Transmitting coil ( 10 ) according to one of claims 1 to 3, wherein the optical contrast pattern ( 11a ; 11b ; 11c ) Has lines or shapes of different thickness or extension. Charging station ( 100 ) for inductive energy transmission to a motor vehicle ( 20 ), comprising: a transmitting coil ( 10 ) according to one of claims 1 to 4, the coil plane horizontally in the bottom of the charging station ( 100 ) is arranged; and a coil control device ( 14 ), which are connected to a power grid ( 15a ; 15b ) is connectable, and which is adapted to the transmitting coil ( 10 ) to supply with electric current. Charging station ( 100 ) according to claim 5, further comprising: a communication device ( 12 ), which with the coil control device ( 14 ) and which is adapted to wirelessly transmit a position and / or identification radio signal (RF). Charging station ( 100 ) according to claim 6, wherein the communication device ( 12 ) is further adapted to provide a reference radio signal on the geometric nature of the optical contrast pattern ( 11a ; 11b ; 11c ) of the sample plate ( 11 ). Procedure ( 30 ) for positioning an inductive power transmission device, comprising the steps of: detecting ( 31 ) of an optical contrast pattern ( 11a ; 11b ; 11c ), which is mounted on a sample plate ( 11 ) in a plane above the coil plane of a stationary transmitting coil ( 10 ) is applied to an inductive energy transmission device, by means of at least one optical detection device ( 22 ) of a vehicle ( 20 ), which is a receiving coil ( 21 ) for inductive energy transmission from the transmitting coil ( 10 ) having; Drive ( 32 ) of an automatic parking assistance system of the vehicle ( 20 ) based on one of the detected optical contrast patterns ( 11a ; 11b ; 11c ) dependent detection signal of the at least one optical detection device ( 22 ); and automatic parking ( 33 ) of the vehicle using the automatic parking assistance system, so that the receiving coil ( 21 ) for inductive energy transmission relative to the transmitting coil ( 10 ) is positioned. Procedure ( 40 ) for detecting a foreign object (F) between a transmitting coil ( 10 ) and a receiving coil ( 21 ) of an inductive energy transmission device, comprising the steps of: detecting ( 41 ) of an optical contrast pattern ( 11a ; 11b ; 11c ), which is mounted on a sample plate ( 11 ) in a plane above the coil plane of a stationary transmitting coil ( 10 ) is applied to an inductive energy transmission device, by means of at least one optical detection device ( 26 ) of a vehicle ( 20 ), which is a receiving coil ( 21 ) for inductive energy transmission from the transmitting coil ( 10 ) having; To compare ( 42 ) of the detected optical contrast pattern ( 11a ; 11b ; 11c ) with a reference pattern; and determining ( 43 ) that a foreign object (F) between the transmitting coil ( 10 ) and the receiving coil ( 21 ) is located, if the detected optical contrast pattern ( 11a ; 11b ; 11c ) has a deviation above the detection threshold with respect to the reference pattern.

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