Device with secondary coil for inductive charge transfer

Abstract

Device for installation in a vehicle for inductive electrical charging or discharging of the vehicle by means of a primary coil (1'), wherein the device has an underbody panel (4), wherein the device has a secondary coil (1), wherein the secondary coil (1) is electrically connected to a power unit (2) of the vehicle via a reversibly connectable electrical connection (3), wherein the secondary coil (1) is mounted on the upper side of the underbody panel (4), characterized in that the secondary coil (1) is printed on the underbody panel (4).

Description

[0001] The present invention relates to a device for installation in a vehicle, comprising a secondary coil, for an inductive electrical charge transfer between a primary coil and the secondary coil.

[0002] As part of environmental protection efforts, more and more vehicle owners are opting for electric vehicles or plug-in hybrid vehicles. Charging these vehicles usually takes place at a charging station using a plug connection between the charging station and the vehicle. However, this is inconvenient. Firstly, plugging in the vehicle requires an additional step for the driver. Secondly, the multitude of different plug systems means that a correspondingly large number of plug adapters must be carried in the vehicle.

[0003] Furthermore, constantly moving components, such as the cable from the charging station to the vehicle or the plug of the charging station, are subject to wear and tear and the risk of damage.

[0004] Inductive electrical charge transfer to vehicles is known from the prior art. Publication WO 2014 / 206661 A1 discloses an inductive charging device for charging an electric vehicle, in which energy is transferred from a primary coil to a secondary coil. Publication DE 10 2013 214311 A1 discloses a receiver coil for the inductive electrical charging of an electric vehicle, which is integrated into a transmission oil pan. Publication DE 10 2011 108544 A1 discloses secondary coils which are mounted on the underbody of a vehicle. Publication DE 10 2017 011388 A1 discloses cooling a secondary coil with a shielding element equipped with cooling fins. The secondary coil is screwed in place. The publication DE 10 2009 033 235 A1 discloses a power supply unit comprising a secondary coil for land vehicles with a connecting piece for connecting the power supply unit to the vehicle's electrical system.German patent application DE 10 2015 216 157 A1 discloses a device for inductively charging a vehicle, wherein this device has a ferrite layer on the upper side of the vehicle's underbody paneling. German patent application DE 10 2016 015 255 A1 discloses a device for wirelessly charging an electrical energy storage device of a vehicle, comprising a coil that is movable along the longitudinal, transverse, and vertical directions of the vehicle.

[0005] A disadvantage of the current state of the art is that either elaborate coil housings have to be installed to accommodate the secondary coils, or that the secondary coils are not easily replaceable, but are usually permanently connected to the vehicle, especially to a power unit of the vehicle.

[0006] It is therefore an object of the present invention to provide a device and a method which, compared to the prior art, offer the savings of a coil housing, the saving of installation space in the vehicle, the possible integration into a component of the vehicle and easy interchangeability.

[0007] This problem is solved by a device according to claim 1. In this way, a device is provided which is suitable for the inductive electrical energy transfer from the primary coil to the secondary coil. The primary coil is located outside the vehicle and connected to a power grid. It acts as a transmitter during the energy transfer process. The secondary coil is electrically connected to the vehicle and acts as a receiver during the energy transfer process. The primary and secondary coils are preferably designed as circular coils or as double-D coils. The secondary coil is reversibly connected to power electronics, for example, an AC / DC converter. This can be achieved, for example, via a plug connection, a screw connection, or a magnetic contact. The connection is detachable, so that the device can be easily attached to or detached from the vehicle.The device may additionally include control elements for controlling an external charging device or identification elements for identifying a vehicle during a charging process. The underbody panel of the device may be part of the vehicle's underbody panel. According to the invention, the device is preferably designed for installation on the underside of a vehicle.

[0008] Advantageous embodiments and further developments of the invention can be found in the dependent claims and in the description with reference to the drawings.

[0009] According to a preferred embodiment of the invention, the device has a ferrite layer at least partially attached to the underbody panel on an upper side which, when the device is installed in the vehicle, faces away from the ground. This advantageously shields the secondary coil from interfering influences from the direction of the vehicle. The ferrite layer can be screwed, glued, or clipped onto the underbody panel. Alternatively, the ferrite layer could be attached directly to the underside of the vehicle rather than to the underbody panel. The latter would facilitate easier replacement of parts of the device.

[0010] According to the invention, the secondary coil is mounted on the upper side of the underbody panel. This advantageously protects the secondary coil from mechanical damage, such as that caused by stone chips, by the underbody panel. Preferably, the underbody panel is made of plastic. This enables energy transfer from the primary coil to the secondary coil while reducing losses due to damping or stray fluxes.

[0011] In a further preferred embodiment of the present invention, the secondary coil is mounted in the vehicle's underbody paneling. Preferably, the underbody paneling is made of a plastic whose dielectric properties do not affect the energy transfer from the primary coil to the secondary coil. Mounting the secondary coil in the underbody paneling provides good protection against mechanical damage to the secondary coil. Furthermore, this reduces the distance between the primary and secondary coils, which in turn increases the efficiency of the energy transfer.

[0012] According to a further preferred embodiment of the invention, the underbody panel is made at least partially from a ferrite-plastic composite. This enables the shielding of electromagnetic fields that could disrupt energy transfer. The ferrite-plastic composite design still allows for simple shaping of the underbody panel during the production process, as well as high robustness. For example, it is conceivable to install the secondary coil within the underbody panel and to manufacture only those areas of the underbody panel from a ferrite-plastic composite that are not located in a volume through which the majority of the field lines between the primary and secondary coils pass during energy transfer. This would make it possible to shield the secondary coil in a directionally targeted manner. Simultaneously, the shape of the ferrite determines the direction of the magnetic field.This offers the advantage that, in addition to the shielding provided by the ferrite, the shape and orientation of the magnetic field can be determined.

[0013] In a further preferred embodiment of the present invention, the secondary coil is mounted on the underbody panel on a lower side which, when the device is installed in the vehicle, faces the ground. This would make it possible to minimize the distance between the secondary and primary coils. Furthermore, this enables energy transfer between the primary and secondary coils without materials between the two coils that could significantly attenuate the electromagnetic field. It is conceivable that the underbody panel is made at least partially of a ferrite-plastic composite. It is also conceivable that the secondary coil is coated with a protective layer that protects it from mechanical damage, such as from stone chips, or from chemical damage, such as from corrosion.

[0014] According to a further preferred embodiment of the invention, the underbody panel, together with the secondary coil, can be reversibly unscrewed, unclipped, or disconnected from the vehicle. This allows for easy replacement of the secondary coil should it become damaged. The electrical connection between the secondary coil and the vehicle's power unit can be implemented as a clip-on connection or as a screw connection for attaching the underbody panel to the vehicle. This advantageously allows the underbody panel, including the secondary coil, to be installed and removed, and in the same operation, the electrical connection between the secondary coil and the vehicle's power electronics can be established.

[0015] According to the invention, the secondary coil is bonded to the underbody panel. This allows for a simple manufacturing process for the device, eliminating the need for complex manufacturing steps such as screwing or welding. Furthermore, this method makes it possible to precisely adapt the shape of the secondary coil to the specific shape of the underbody panel. For example, spacers could be printed between the underbody panel and the secondary coil. This would allow the shape along the main plane of extension of the secondary coil to be chosen independently of the shape of the underbody panel.

[0016] According to a further preferred embodiment of the invention, the device includes a tracking unit for spatially locating the primary coil. This enables the precise positioning of the secondary coil relative to the primary coil, thus preventing energy transfer losses. It is conceivable that the primary coil is located and that the driver is signaled, based on the information from the primary coil's location, where to drive. Alternatively, the driver could roughly steer the vehicle in the direction of the primary coil, and an autonomous driving program could then handle the precise control of the primary coil.

[0017] Furthermore, it is preferably provided that the device is movable along its main plane of extension relative to the vehicle. This makes it possible, within a framework defined by the vehicle's geometry, to position the secondary coil for energy transfer optimally relative to the primary coil without having to move the vehicle itself. It is conceivable that the device is driven by motors controlled by a control unit based on information from the location of the primary coil obtained from the locating unit.

[0018] A further aspect of the invention is a method for electrical charge transfer to a vehicle using a device according to one of the preceding claims, wherein, in a first step, the vehicle is positioned such that the transmission distance between the secondary coil and the primary coil is so small that inductive energy transfer from the primary coil to the secondary coil is possible; in a second step, an alternating current is induced in the secondary coil by an alternating magnetic field generated by the primary coil; and in a third step, the alternating current induced in the secondary coil is directed to the power unit. This enables the simple charging of a vehicle without complicated handling of cables and plugs. It is conceivable that the energy transfer process is controlled by control elements for controlling an external charging device.Furthermore, it is conceivable that identification elements for identifying a vehicle could identify the vehicle during energy transfer, thus enabling, for example, the control of authorizations to use the primary coil or the billing of transferred energy.

[0019] According to a further preferred embodiment of the invention, the device is the device according to claim 9, wherein, during the first step, the locating unit locates the primary coil and the vehicle is positioned based on this location so that stray flux during inductive energy transfer is minimized. This could be achieved by displaying the correct position to the driver, who then drives to that position. Alternatively, the driver could roughly drive the vehicle in the direction of the primary coil, and an autonomous driving program could then position the vehicle so that the primary and secondary coils are optimally positioned relative to each other.

[0020] In a further preferred embodiment of the present invention, the device is the device according to claim 10, wherein during the first step the locating unit locates the primary coil and the vehicle is positioned based on this location such that stray flux during inductive energy transfer is reduced, and between the first and second steps the device is positioned relative to the vehicle based on this location so that stray flux during inductive energy transfer is minimized. This advantageously allows the secondary coil to be optimally positioned relative to the primary coil without having to ensure that the vehicle itself is in an optimal position. The precise adjustment of the secondary coil relative to the primary coil is achieved by moving the device relative to the vehicle.It is conceivable that the device is driven by motors which are controlled by a control unit based on information from the location of the primary coil with the locating unit.

[0021] Further details, features, and advantages of the invention will become apparent from the drawings and from the following description of preferred embodiments with reference to the drawings. The drawings merely illustrate exemplary embodiments of the invention, which do not limit the inventive concept. Fig. Figure 1 shows a schematic sectional view of the device according to the invention in a preferred embodiment. Fig. Figure 2 shows a schematic sectional view of the device according to the invention in a further preferred embodiment. Fig. Figure 3 shows a schematic sectional view of the device according to the invention in a further preferred embodiment.

[0022] In Fig. Figure 1 shows a schematic cross-sectional view of the device according to the invention in a preferred embodiment. The primary coil 1' is located below the underbody panel 4. The secondary coil 1 is bonded to the side of the underbody panel 4 facing away from the ground. This protects the secondary coil from mechanical damage, such as impacts from stones. The secondary coil 1 is shielded against interference by a ferrite layer. The secondary coil 1 is electrically connected to the vehicle's power unit 2 via the reversibly connectable connection 3. An alternating current in the primary coil 1' generates an alternating magnetic field, which induces an alternating current in the secondary coil 1. This induced alternating current is used to charge the vehicle via the connection 3.

[0023] In Fig. Figure 2 shows a schematic sectional view of the device according to a further preferred embodiment. The primary coil 1' is located below the underbody panel 4. The secondary coil 1 is installed in the underbody panel 4. Thus, the secondary coil is protected from mechanical influences, for example, from stone impacts, while the distance from the primary coil 1' to the secondary coil 1 is smaller compared to the corresponding distance in the Fig. The design shown in Figure 1 is reduced. Above the underbody panel 4 is the ferrite layer 5, which shields the secondary coil 1 against interference. The secondary coil 1 is connected to the vehicle's power unit 2 via the reversibly connectable connection 3, which consists of a clip and a corresponding counterpart. An alternating current in the primary coil 1' generates an alternating magnetic field, which induces an alternating current in the secondary coil 1. This induced alternating current charges the vehicle via the connection 3. The secondary coil 1, together with the underbody panel 4, is clipped to the vehicle and can be reversibly removed as a component.

[0024] In Fig.Figure 3 shows a schematic sectional view of the device according to a further preferred embodiment of the invention. The primary coil 1' is located below the underbody panel 4. The secondary coil 1 is located between the primary coil 1' and the underbody panel 4. The secondary coil 1 is printed onto the underbody panel 4. The underbody panel 4 is made of a ferrite-plastic composite. The secondary coil 1 is connected to the vehicle's power unit 2 via the reversibly connectable connection 3 in the form of a plug and a corresponding socket. An alternating current in the primary coil 1' generates an alternating magnetic field, which induces an alternating current in the secondary coil 1. The vehicle is charged via the connection 3 using this induced alternating current.

Claims

[1] Device for installation in a vehicle for inductive electrical charging or discharging of the vehicle by means of a primary coil (1'), wherein the device comprises an underbody panel (4), wherein the device comprises a secondary coil (1), wherein the secondary coil (1) is electrically connected to a power unit (2) of the vehicle via a reversibly connectable electrical connection (3), wherein the secondary coil (1) is attached to the upper side of the underbody panel (4), characterized by that the secondary coil (1) is printed on the underbody panel (4). [2] Device according to claim 1, wherein the device has at least partially a ferrite layer (5) on an upper side of the underbody paneling (4), which side faces away from the ground when the device is installed in the vehicle. [3] Device according to one of the preceding claims, wherein the secondary coil (1) is mounted in the underbody panel (4) of the vehicle. [4] Device according to one of claims 1, 2 or 3, wherein the underbody panel (4) is at least partially made of a ferrite-plastic mixture. [5] Device according to claim 4, wherein the secondary coil (1) is attached to the underbody panel (4) on a lower side, which faces the ground in a state of the device installed in the vehicle, of the underbody panel (4). [6] Device according to one of claims 2, 3 or 5, wherein the underbody panel (4) together with the secondary coil (1) can be reversibly unscrewed, unclipped or unplugged from the vehicle. [7] Device according to one of the preceding claims, wherein the device comprises a locating unit (6) for spatially locating the primary coil (1'). [8] Device according to claim 7, wherein the device is movable along its main extension plane relative to the vehicle. [9] Method for an electrical charge transfer to a vehicle with a device according to one of the preceding claims, wherein in a first step the vehicle is positioned such that a transmission path between the secondary coil (1) and the primary coil is so small that an inductive energy transfer from the primary coil (1') to the secondary coil (1) is possible; in a second step, an alternating current is induced in the secondary coil (1) by means of an alternating magnetic field generated by the primary coil (1') and in a third step, the alternating current induced in the secondary coil (1) is passed to the power unit (2). [10] Method according to claim 9, wherein the device is the device according to claim 9, wherein during the first step the locating unit (9) locates the primary coil (1') and the vehicle is positioned based on the locating so that a stray flux in the inductive energy transfer is minimized. [11] Method according to claim 9, wherein the device is the device according to claim 10, wherein during the first step the locating unit (9) locates the primary coil (1') and the vehicle is positioned based on the locating such that a stray flux in the inductive energy transfer is reduced and between the first step and the second step the device is positioned based on the locating relative to the vehicle such that a stray flux in the inductive energy transfer is minimized.

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