DE102014216358A1 - Charging station, charging system and method for inductive charging of a motor vehicle energy storage - Google Patents

Abstract

A charging station (100, 200, 300), a charging system and a method for inductively charging a motor vehicle energy storage are described. The charging station (100, 200, 300) has a generator unit (110) arranged to provide an alternating current, and a primary coil arrangement (120, 220, 320) which is energetically coupled to the generator unit (110) such that the primary coil arrangement (110) 120, 220, 320) is excitable by the alternating current. The primary coil assembly (120, 220, 320) comprises (a) a longitudinal axis extending along a z-direction, (b) a first dimension along an x-direction which is perpendicular to the z-direction, and (c ) has a second dimension along a y-direction which is perpendicular to the z-direction and perpendicular to the x-direction. The first dimension of the primary coil arrangement (120, 220, 320) is larger by at least a factor 1, 2 than the size of a secondary coil (190) of the electromobile motor vehicle along the x direction, with which secondary coil (190) the primary coil arrangement can be inductively coupled.

Description

The present invention generally relates to the technical field of inductive transmission of energy from a primary coil to a secondary coil. The present invention relates in particular to a charging station, a charging system and a method for inductively charging an electrical energy store of an electromobile motor vehicle.

As electromobile motor vehicles are generally referred to motor vehicles that are wholly or partially powered by electrical energy. Electromobile motor vehicles may be, for example, motor vehicles with a hybrid drive or pure electric vehicles. In addition to an electric drive machine, a hybrid drive additionally comprises a conventional internal combustion engine, in order in particular to increase the range of the electromobile motor vehicle. Electromobile motor vehicles, which in addition to an electric drive machine still have an internal combustion engine, are referred to as hybrid motor vehicle. A pure electric vehicle has as a drive machine only one or more electric drive machines or electric motors.

Electric energy storage of electromobile motor vehicles can be charged wired or wirelessly via an inductive energy transfer in a corresponding charging station.

When inductive charging of electromobile motor vehicles or their energy storage is an optimal alignment of (a) of the charging station associated primary coil and (b) of the electromobile motor vehicle associated secondary coil is crucial for a safe and effective power transmission. The efficiency of an inductive charging process is at a suitable compensation of the resonant circuits, which are associated with the primary coil and the secondary coil, then maximum when both coils are aligned exactly to each other or the centers of the two coils are superimposed. A certain offset between both coils results in reduced efficiency.

If, for example, an offset of only a few percent in relation to the diameter of the coils occurs in each case with a round coil geometry of the primary and secondary coils, then the efficiency of the inductive energy transmission is influenced only to a limited extent. At a relative offset of, for example, 10%, this efficiency drops noticeably.

Since both the secondary coil in the vehicle, as well as the primary coil of the loading space when parking for the driver of an electrified motor vehicle to be charged are not visible, must always be expected with a horizontal offset of both coils each other. Therefore, in order to optimize the efficiency of the inductive energy transfer, the driver must be actively and / or passively supported during a parking process in a charging station.

Such support of the driver can for example take place via a satellite-based positioning system, which, however, can only be used for a spatially very large positioning due to the limited resolution. A comparatively fine positioning can be made possible by the use of additional sensors. For example, the driver of the relevant electromobile motor vehicle can be supported by a graphic display. However, this also has certain disadvantages. On the one hand, it can be assumed that the costs of a sensor-based positioning system increase with increasing resolution. On the other hand, such a precise parking process will be associated with a certain maneuvering, since the driver can not steer his vehicle, despite highly accurate positioning system, as arbitrary as possible. In this case, a correct positioning transverse to the parking direction is more difficult to achieve than the orientation of the vehicle or the secondary coil with respect to the primary coil along the direction of parking.

The invention has for its object to improve the inductive transmission of energy from the primary coil of a charging station to the secondary coil of an electromobile motor vehicle, in particular with regard to a non-optimal relative positioning between the secondary and primary coil.

This object is solved by the subject matters of the independent claims. Advantageous embodiments, further features and details of the present invention will become apparent from the dependent claims, the description and the drawings. In this case, features and details that are described in connection with the charging device or the charging system are of course also in connection with the method, and in each case vice versa, so that with respect to the disclosure of this invention to the individual aspects of the invention always reciprocal reference can be made.

According to a first aspect of the invention, a charging station for inductively charging an energy store of an electromobile motor vehicle is described. The charging station described points to a generator unit, set up for Providing an alternating current, and a primary coil assembly, which is energetically coupled to the generator unit such that the primary coil assembly is excitable by the alternating current. The primary coil assembly comprises (a) a longitudinal axis extending along a z-direction, (b) a first dimension along an x-direction which is perpendicular to the z-direction, and (c) a second dimension along a y Direction, which is perpendicular to the z-direction and perpendicular to the x-direction. According to the invention, the first dimension of the primary coil arrangement is at least a factor of 1.2 greater than the size of a secondary coil of the electromobile motor vehicle along the x-direction, with which secondary coil the primary coil arrangement can be inductively coupled.

The inductive charging station described is based on the finding that when the primary coil arrangement along the x-direction is consciously dimensioned larger than the secondary coil, an inductive energy transfer from the primary coil arrangement to the secondary coil can be achieved with high efficiency or with high efficiency when the secondary coil is offset along the x-direction with respect to a center of the primary coil assembly. When retracting an electromobile motor vehicle with a rechargeable energy storage in the described charging station, the x-direction can then be aligned perpendicular to the retraction, so that a lateral offset when retracting the motor vehicle in the described charging station no or at least no major impact on the effectiveness of the inductive Energy transfer and thus on the efficiency of the inductive charging has.

Taking into account the fact already explained above that a correct positioning of the electromobile motor vehicle along the retraction direction can be achieved very easily, a high efficiency of the inductive energy transfer can also be achieved with the charging station described here if during a charging process the positioning of the motor vehicle resp the secondary coil of the motor vehicle in the charging station along the x-direction is inaccurate.

The term longitudinal axis of the primary coil arrangement is to be understood in this document as the axis around which the current-carrying coil wire is wound. In a plane of symmetry of the primary coil arrangement, the direction of the magnetic field can therefore be in a known manner at least approximately parallel to the longitudinal axis.

According to an embodiment of the invention, the first dimension of the primary coil assembly is at least a factor of 1.5 and preferably at least a factor of 2.0 greater than the size of the secondary coil along the x-direction.

The greater the difference between the x-dimension (ie the dimension along the x-direction) of the primary coil assembly and the x-size (ie, the size of the secondary coil along the x-direction), the less sensitive is the inductive energy transfer efficiency the primary coil assembly and the secondary coil in a mispositioning of the electromobile motor vehicle or the secondary coil of the electromobile motor vehicle along the x-direction.

According to a further embodiment of the invention, the first dimension is at least a factor of 1.5, preferably at least a factor of 2, more preferably at least a factor of 2.5, and most preferably at least a factor of 3 larger than the second dimension.

By a deliberately unequal dimensioning of the primary coil assembly in different directions, which are each oriented perpendicular to the longitudinal axis of the primary coil assembly, the efficiency of an inductive energy transfer from the primary coil assembly to a secondary coil is typically initially reduced. However, for a given size of the cross-sectional area of the primary coil arrangement, it can be improved in a simple manner, at least in the case when the secondary coil assigned to the energy store to be charged has a certain spatial offset along the x-direction with respect to the primary coil arrangement. If, as already described above, the x-axis within the charging station is aligned at least approximately perpendicular to a retraction direction of the relevant motor vehicle with the primary coil and the energy storage to be charged (the y-direction is then at least approximately the retraction direction), then leads to an offset the entire vehicle perpendicular to its direction of retraction to no or only a very small reduction in the efficiency of the inductive energy transfer.

Illustrated clearly, the eccentricity of the primary coil arrangement described here can advantageously contribute to a particularly high independence of the inductive energy transfer efficiency from the exact position of the motor vehicle or secondary coil of the motor vehicle along the x-axis direction.

According to a further embodiment of the invention, the first dimension is greater than 40 cm, preferably greater than 60 cm, more preferably greater than 80 cm and even more preferably greater than 100 cm.

The larger the first dimension of the primary coil arrangement along the x-direction, the lower the dependence of the efficiency of the inductive energy transfer in a mispositioning of the secondary coil with respect to the center of the primary coil arrangement of the described charging station.

According to a further exemplary embodiment of the invention, the charging station further has an insertion track which extends along the x-direction. The Einfahrspur is designed such that a motor vehicle with a charged energy storage along the Einfahrspur is retractable into the charging station.

The described Einfahrspur can be any physical structure, which is designed or at least suitable to determine the direction along which the electromobile vehicle with the charged energy storage in the charging station for the purpose of inductive charging must be retracted or at least retracted. In a particularly simple case, the insertion lane may also simply be a suitable marking which indicates to a driver of the relevant electromobile motor vehicle along which direction he should drive into the charging station described.

Of course, the drive-in lane can also help to reliably drive the motor vehicle out of the charging station after a hopefully successful charging of the energy store.

According to a further exemplary embodiment of the invention, the primary coil arrangement has a single coil with at least one winding whose enclosed area has the first dimension along the x-direction and the second dimension along the y-direction.

The realization of the primary coil arrangement with only one coil has the advantage that the primary coil arrangement can be realized in a particularly simple manner. It is only necessary to choose the cross section so that it has a larger dimension along the x-direction than along the y-direction.

According to a further embodiment of the invention, the single coil is a round coil having an eccentricity with respect to the x-direction and the y-direction.

The coil described with this embodiment can be produced in a simple manner, for example, by winding a suitable coil wire around a core having a certain eccentricity. In this case, for example, the core may have an elliptical cross-sectional shape perpendicular to the z-direction.

The cross-sectional shape or the cross-sectional area of the round coil preferably has an axis symmetry with respect to the y-direction. This means that a long major axis of the eccentric cross-sectional area of the coil is parallel to the x-direction and a short major axis of the eccentric cross-sectional area is parallel to the y-direction.

According to a further embodiment of the invention, the single coil is a polygonal coil having different dimensions with respect to the x-direction and the y-direction.

The square coil may have any polygon as a cross-sectional area. However, here too, the shape of the polygon preferably has an axis symmetry with respect to the y-direction.

Such axial symmetry of the cross-sectional area of the polygonal coil can be realized in a special way, that this cross-sectional area has the shape of a rectangle. The longer side of the rectangle may run parallel to the x-direction and the shorter side of the rectangle parallel to the y-direction.

However, an axis symmetry of the cross-sectional area with respect to the y-direction can also be realized with other polygonal shapes such as a trapezoid or a rhombus. In the case of a rhombus, the longer major axis of the rhombus, which connects two opposing vertices, runs parallel to the y-direction.

According to a further embodiment of the invention, the primary coil arrangement has a plurality of individual coils, which are arranged next to one another in a xy plane spanned by the x-direction and the y-direction.

The primary coil assembly can thus be constructed in a simple manner with a plurality of smaller individual coils, which can be dimensioned in each case in a suitable manner. When using individual coils of the same type, the described primary coil assembly can be modular with a suitable dimensioning, which in turn leads to a great advantage in terms of the manufacturing cost of the charging station described.

In accordance with the basic principle of the present invention, along the x-direction, the number of individual coils arranged side by side is so large that the size of the entirety of the individual coils along the x-direction is larger than the size of the secondary coil along the x-direction.

According to a further embodiment of the invention, the individual coils are arranged within the xy plane in an array.

Depending on the specific application, the described array (a) may be one-dimensional, i. the individual coils are arranged along one direction and in particular along the x-direction, or (b) be two-dimensional.

The described arrangement of the individual coils in an array may mean, in particular, that the individual coils are arranged at predetermined positions within the described xy plane, so that each individual coil is equidistant from at least one adjacent individual coil at least along the x direction.

According to a further embodiment of the invention, the generator unit is designed such that the individual coils are each selectively activatable.

By a selective activation of the various individual coils can be achieved in an advantageous manner that only those individual coils are involved in the inductive energy transfer, which have an overlap with the secondary coil with respect to the xy plane.

It should be noted that for a suitable selective activation of the individual coils it is of course necessary to know the current position of the secondary coil mounted on the electromobile motor vehicle. This can be done with a precise knowledge of the position of the secondary coil in relation to a chassis of the motor vehicle in a simple manner by suitable sensors which measure after retraction of the motor vehicle in the described charging station, the exact position of the motor vehicle. The resulting position data of the motor vehicle can then be transferred to a control unit, which ensures activation of only those individual coils having the above-described overlap with the secondary coil.

In the event that the second dimension of the array of individual coils is greater than the size of the secondary coil along the y-direction, then by an appropriate selective activation of individual coils and an offset between the primary coil assembly and the secondary coil along the y-axis compensated thereby be that preferably only those individual coils are used for the inductive energy transfer, which overlap individual coils at least partially at least along the y-direction with the secondary coil.

According to a further exemplary embodiment of the invention, the dimension of each individual coil is smaller than the size of the secondary coil along the x-direction along the x-direction by at least a factor 2, preferably by at least a factor 4 and more preferably by at least a factor 8. This can in particular have the advantage that the shape or the size of the active part of the primary coil arrangement can be adapted to the shape or the size of the secondary coil with high accuracy. As a result, it can be reliably achieved that, for the inductive energy transmission, the cross-sectional area of the secondary coil is utilized as completely as possible by the respective activated individual coils. Furthermore, it can be prevented in a simple manner that those individual coils, which have no or only a partial overlap with the secondary coil with respect to the xy plane, are activated and thus an advantageous generation of non-usable magnetic field components is prevented.

It should be noted that the dimension of each individual coil can also be smaller than the size of the secondary coil along the y-direction by at least a factor 2, preferably by at least a factor 4 and more preferably by at least a factor 8, along the y-direction , In this way, the position of the activated part of the primary coil assembly can be adapted with high accuracy to the current position of the secondary coil along the y-direction.

According to a further aspect of the invention, a charging system for inductively charging an electrical energy store of an electromobile electric vehicle is described. The described charging system comprises (a) a charging station of the type described above and (b) the secondary coil.

The inductive charging system described is based on the finding that the charging station described above can magnetically interact with the secondary coil of the electromobile motor vehicle in such a way that an inductive energy transfer with high efficiency is ensured even if the position of the secondary coil is inadvertently offset relative to a center of the primary coil arrangement can be.

According to a further aspect of the invention, a method for inductively charging an energy store of an electromobile motor vehicle described. The described method comprises (a) retracting the electromobile motor vehicle into a charging station of the type described above, such that a secondary coil overlaps the armature with respect to a plane spanned by the x-direction and the y-direction (B) providing an alternating current with the generator unit of the charging station, and (c) energizing the primary coil arrangement with the provided alternating current.

The inductive charging method described is also based on the knowledge that when the x-dimension (ie the dimension along the x-direction) of the primary coil arrangement is deliberately greater than the x-size (ie the size along the x-direction) of the secondary coil , Even with an offset of the secondary coil with respect to a center of the primary coil assembly, an inductive energy transfer from the primary coil assembly to the secondary coil can be achieved with high efficiency or with a high efficiency.

Further advantages and features of the present invention will become apparent from the following exemplary description of presently preferred embodiments. The individual figures of the drawing of this application are merely to be regarded as schematic and not to scale.

1a shows a charging system for inductively charging an electrical energy storage device of a motor vehicle, the charging system having a charging station with an oval primary coil and a motor vehicle associated with the round secondary coil which overlaps with the center of the oval primary coil.

1b shows the charging system of 1a in a state where the round secondary coil is in an eccentric position relative to the oval primary coil but still completely overlaps with the oval primary coil.

2a shows a charging system for inductively charging an electrical energy storage device of a motor vehicle, wherein the charging system has a charging station with a rectangular primary coil and a motor vehicle associated square secondary coil, which overlaps with the center of the rectangular primary coil.

2 B shows the charging system of 2a in a state where the square secondary coil is in an eccentric position with respect to the rectangular primary coil but still completely overlaps with the rectangular primary coil.

3 shows a charging system for inductive charging of an electrical energy storage device of a motor vehicle with a charging station, which has a primary coil assembly with a plurality of arranged in an array individually activatable individual coils.

It should be noted that in the drawing features or components of different embodiments, which are the same or at least functionally identical with the corresponding features or components of the embodiment, are provided with the same reference numerals or with other reference numerals, which are only in their first digit from the reference number of a (functionally) corresponding feature or a (functionally) corresponding component. In order to avoid unnecessary repetitions, features or components already explained on the basis of a previously described embodiment will not be explained in detail later.

It should also be noted that the embodiments described below represent only a limited selection of possible embodiments of the invention. In particular, it is possible to suitably combine the features of individual embodiments with one another, so that a multiplicity of different embodiments are to be regarded as obviously disclosed to the person skilled in the art with the embodiment variants explicitly illustrated here.

The 1a and 1b each show a charging system for inductive charging of an electric energy storage, not shown, of an electric motor vehicle, also not shown. The charging system has a charging station 100 with a generator unit 110 and one as an oval primary coil 120 formed primary coil assembly 120 on which of the generator unit 110 can be energized with an alternating electric current. The charging system further comprises a motor vehicle associated round secondary coil 190 on.

In 1a fall in an xy plane, which is spanned by the illustrated x-direction and the y-direction shown, the centers of the two coils 120 and 190 together. An inductive coupling between both coils 120 and 190 is somewhat weaker than with two equal sized coils with a complete overlap. Taking into account the two different geometries of the two coils 120 and 190 This inductive coupling and thus the efficiency of an inductive energy transfer between the two offset arranged coils 120 and 190 at least with a suitable compensation of Resonant frequencies of the resonant circuits, the two coils 120 and 190 are assigned to be maximum.

In 1b is located in a projection on the xy plane along a direction perpendicular to the x-direction and to the y-direction z-direction round secondary coil 190 although within the cross-sectional area of the oval primary coil 120 However, the two coils are arranged eccentrically to each other. The inductive coupling between both coils 120 and 190 is weaker than the concentric in 1a However, it is much stronger than two coils that do not overlap or only very slightly overlap.

Like from the 1a and 1b can be seen, points the charging station 100 another lane 130 which extends along the y-direction. The entry lane 130 is formed such that the electromobile motor vehicle along the Einfahrspur 130 is retractable into the charging station. As already explained above, the Einfahrspur 130 be any structure or marking which is suitable to determine the direction along which the electromobile motor vehicle in the charging station 100 must be retracted for the purpose of inductive charging of an electrical energy storage or at least to be retracted.

2a shows a charging system 200 for inductively charging an electrical energy store of a motor vehicle. The charging system largely corresponds to the charging system, which in the 1a and 1b is shown. The only differences between the two charging systems are that the primary coil assembly 220 is formed as a rectangular primary coil and that the secondary coil 290 has an at least approximately square cross-section.

In 2a fall the centers of the two coils 220 and 290 in the xy-plane together. With suitable compensation, the best possible efficiency of an inductive energy transmission between the two coils of different size results.

In 2 B is the square secondary coil 290 in relation to the rectangular primary coil 220 in an eccentric position. In accordance with 1b This results in a somewhat reduced efficiency of the inductive energy transfer, which is still significantly greater than with two coils that do not overlap or only very slightly.

To put it clearly, in the embodiments of the invention described above, the tolerance for a coil offset is minimized by changing the coil shape and / or the size ratio between the two coils in comparison to a charging system with two identically designed coils. Namely, if the primary coil is not round, but is made, for example, oval or rectangular, then the tolerance to offset in one direction (here, the x direction) can be increased. The more field lines of a primary field generated by the primary coil pass through the secondary coil, the more energy is also transmitted to the secondary side.

In this connection it is obvious that an optimal penetration of magnetic field lines is given when the two coils overlap 1: 1. Furthermore, it is obvious that in the charging system described here, the inductive energy transfer efficiency without offset (see 1a and 2a ) greater than that with offset (see 1b and 2 B ). The larger the primary coil compared to the secondary coil, the worse is the maximum achievable efficiency, since the secondary coil is penetrated in this case, only a part of the magnetic field generated by the primary coil. The tolerance to an offset between the two coils, however, increases, since the secondary coil is interspersed in this case, even at different offsets of the same field strength.

If you want to minimize the dependence of the efficiency of a spatial offset between the two coils, then this can be achieved according to the embodiments described above by a larger primary coil. Of course, the secondary coil can not be arbitrarily small in this case. By a corresponding shaping of the primary coil, moreover, the tolerance in a certain direction can be minimized.

However, due to the typically limited maneuverability of a motor vehicle transversely to its driving or parking direction and the resulting difficulty in correctly aligning the motor vehicle, it may be of great advantage to tolerate a coil offset at least transversely to the direction of travel at the expense of somewhat reduced efficiency improve. If the primary coil is therefore designed not circular but oval or rectangular, this tolerance can be improved at least with respect to one direction.

It should be noted that also an increase of the secondary coil compared to the primary coil would have similar advantages. Of course, the shape of the secondary coil can of course be adapted to the parking situation of the motor vehicle in the charging station as described above. In this case, on the one hand increases the tolerance for a horizontal offset and on the other hand, the overall efficiency of the inductive charging increases. The reason for this is that in a larger secondary coil this is also interspersed by stray fields. This increases both the efficiency and the tolerance against horizontal offset. A disadvantage of this variant, however, is the higher weight of the secondary side of the charging system, which leads to an increased total weight of the electromobile motor vehicle.

3 shows a charging system for inductive charging of an electrical energy storage device of a motor vehicle with a charging station 300 which is a primary coil arrangement 320 with a plurality of individually activatable individual coils arranged in an array 322 . 324 having.

According to the embodiment shown here, depending on the position of the secondary coil exactly those individual coils 324 activated or with alternating current from the generator unit 110 which are in the xy plane within the range of the secondary coil 190 are located. Thus, an at least approximately optimal overlap at least approximately the same size between the secondary coil and the active primary coil arrangement and thus a particularly high efficiency of an inductive energy transfer can be ensured.

Illustratively, according to the embodiment shown here, instead of a single primary coil, an entire array of smaller individual coils 322 . 324 for the charging station 300 used. The parking process of a motor vehicle with a charged energy storage in the charging station 300 must in this case no longer have the required accuracy, if only those single coils 324 which are activated in the area of the secondary coil 190 fall.

The exact position of the secondary coil 190 inside the charging station 300 can be determined for example by means of an inductive measuring principle. Because only those single coils 324 be energized, over which the secondary coil 190 a unique even relatively imprecise parking operation can be sufficient to still ensure an at least approximately optimal efficiency of the inductive energy transfer.

An advantage of the invention described in this document or of all embodiments of the invention is i.a. a nearly constant effectiveness of an inductive energy transfer with short maneuvering times until a suitable and largely optimal vehicle position within the charging station is achieved. It may be ensured by (a) suitably shaping a coil and / or (b) by selectively selectively activating one or more individual coils so that adequate charge efficiency is always achieved despite non-ideally aligned coils.

LIST OF REFERENCE NUMBERS

100

 charging station

110

 generator unit

120

 Primary Coil Assembly / Primary Coil (Oval)

130

 drive-in

190

 Secondary coil (round)

200

 charging station

220

 Primary Coil Assembly / Primary Coil (Rectangular)

290

 Secondary coil (square)

300

 charging station

320

 Primary coil arrangement

322

 Single coils (deactivated)

324

 Single coils (activated)

Claims (14)

Charging station for inductive charging of an energy storage device of an electromobile motor vehicle, the charging station ( 100 . 200 . 300 ) comprising a generator unit ( 110 ) arranged to provide an alternating current, and a primary coil arrangement ( 120 . 220 . 320 ) connected to the generator unit ( 110 ) is energetically coupled in such a way that the primary coil arrangement ( 120 . 220 . 320 ) is excitable by the alternating current, wherein the primary coil arrangement ( 120 . 220 . 320 ) has (a) a longitudinal axis extending along a z-direction, (b) a first dimension along an x-direction which is perpendicular to the z-direction, and (c) a second dimension along a y-direction which is perpendicular to the z-direction and perpendicular to the x-direction, wherein the first dimension of the primary coil arrangement ( 120 . 220 . 320 ) is at least a factor 1.2 greater than the size of a secondary coil ( 190 ) of the electromobile motor vehicle along the x-direction, with which secondary coil ( 190 ) The primary coil assembly is inductively coupled. Charging station according to the preceding claim, wherein the first dimension of the primary coil arrangement ( 120 . 220 . 320 ) is at least a factor of 1.5 and preferably at least a factor of 2.0 greater than the size of the secondary coil ( 190 ) along the x-direction. Charging station according to one of the preceding claims, wherein the first dimension of the primary coil arrangement ( 120 . 220 . 320 ) by at least a factor of 1.5, preferably by at least a factor of 2, more preferably by at least a factor of 2.5 and most preferably at least a factor of 3 greater than the second dimension of the primary coil assembly ( 120 . 220 . 320 ). Charging station according to one of the preceding claims, wherein the first dimension of the primary coil arrangement ( 120 . 220 . 320 ) is greater than 40 cm, preferably greater than 60 cm, more preferably greater than 80 cm and even more preferably greater than 100 cm. Charging station according to one of the preceding claims, further comprising a Einfahrspur ( 130 ), which extends along the y-direction, along which a motor vehicle with a rechargeable energy storage in the charging station ( 100 . 200 . 300 ) is retractable. Charging station according to one of the preceding claims 1 to 5, wherein the primary coil arrangement comprises a single coil ( 120 . 220 ) having at least one winding whose trapped surface has the first dimension along the x direction and the second dimension along the y direction. Charging station according to the preceding claim 6, wherein the single coil is a round coil ( 120 ) which has an eccentricity with respect to the x-direction and the y-direction. Charging station according to the preceding claim 6, wherein the single coil is a polygonal coil ( 220 ) which has different dimensions with respect to the x-direction and the y-direction. Charging station according to one of the preceding claims 1 to 5, wherein the primary coil arrangement comprises a plurality of individual coils ( 322 . 324 ), which are arranged side by side in an xy-plane spanned by the x-direction and the y-direction. Charging station according to the preceding claim, wherein the individual coils ( 322 . 324 ) are arranged within the xy plane in an array. Charging station according to one of the two preceding claims, wherein the generator unit ( 110 ) is formed such that the individual coils ( 322 . 324 ) are each selectively activated. Charging station according to one of the three preceding claims, wherein along the x-direction the dimension of each individual coil ( 322 . 324 ) is smaller by at least a factor 2, preferably by at least a factor 4 and more preferably by at least a factor 8, than the size of the secondary coil ( 190 ) along the x-direction. Charging system for inductive charging of an electrical energy store of an electromobile electric vehicle, the charging system having a charging station ( 100 . 200 . 300 ) according to one of the preceding claims, and the secondary coil ( 190 ). Method for inductively charging an energy store of an electromobile motor vehicle, the method comprising driving the electromobile motor vehicle into a charging station ( 100 . 200 . 300 ) according to one of claims 1 to 12 along the y-direction, so that a secondary coil ( 190 ) with respect to a plane which is spanned by the x-direction and by the y-direction, an overlap with the primary coil arrangement ( 120 . 220 . 320 ) of the charging station ( 100 . 200 . 300 ), providing an alternating current with the generator unit ( 190 ) of the charging station ( 100 . 200 . 300 ), and energizing the primary coil assembly ( 120 . 220 . 320 ) with the provided AC.

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