NL2023693B1

NL2023693B1 - Automatic connection device

Info

Publication number: NL2023693B1
Application number: NL2023693A
Authority: NL
Inventors: Cornelis Snijders Tom; Joseph Meessen Koen; Hendrikus Albertus Johannes Venema Stefanus
Original assignee: Prodrive Tech Bv
Priority date: 2019-08-23
Filing date: 2019-08-23
Publication date: 2021-05-04

Abstract

Automatic connection device 5 Automatic connection device for charging an electric vehicle comprising: an interface for providing electrical energy to a contra-interface, a planar motion stage comprising a ﬁrst moving member, which first moving member is conﬁgured for moving the interface within a plane, a linear actuator conﬁgured for moving the interface in a direction essentially orthogonal to the plane, wherein the ﬁrst moving member is conﬁgured to rotate the interface about a ﬁrst axis essentially parallel to the direction, and 10 wherein the linear actuator comprises a threaded member for converting a rotational motion to a linear motion.

Description

Automatic connection device Technical field

[0001] The present invention is related to an automatic connection device. The present invention is further related to a charging station comprising an automatic connection device and a use of an automatic connection device. A possible application of such automatic connection device is for charging an electric vehicle through conductive or wireless power transfer.

Background art

[0002] Electric vehicle (EV) charging is typically accomplished by a wired connection between a charging station and the vehicle. To this end, the electric vehicle comprises a socket that can be mated with a plug of a charging cable that is removably attached to the charging station. Nowadays, several types of sockets are readily available. However, the disadvantage of all of these regular sockets is that they require manually mating the plug and socket.

[0003] Automated connection systems are known. EP0788212 discloses a system for connecting a groundside power supply to the underside of a vehicle. This system comprises a set of orthogonally arranged moving means for moving a connector in the x-y plane and a pantograph mechanism for moving the connector in the z direction. The main disadvantage of such a system is that the force and speed with which the connector is moved in the z direction is typically not constant without providing additional technical measures. Furthermore, such an automated connection device typically has a relatively large build height, requires a large amount of moving parts, is susceptible to malfunction due to pollutants and is difficult to shield from external influences such as debris or water.

Summary of the invention

[0004] It is an object of the present invention to provide an automated connection system that solves one or preferably all of the disadvantages associated with embodiments according to the prior art.

[0005] According to a first aspect of the invention the object is achieved by providing an automated connection device according to the appended claims.

[0006] The automatic connection device (ACD) is used to realize a charging path to charge a battery powered vehicle. Preferably, embodiments according to the invention are suitable for charging electric vehicles with an alternating current of at least 10 ampere, for instance single phase power at 13 A, 16 A or 32 A respectively providing about 3 kW, 4 kW or

7 kW of power, or three phase power at 16 A, 32 A, 60 A per phase respectively providing about 11 kW, 22 kW or 43 kW. Alternatively, embodiments according to the invention are preferably suitable for charging electric vehicles with a direct current providing for instance between 50 kW and 350 kW (e.g. 120 kW). The ACD comprises an interface (e.g. a connector such as a plug) and a planar motion stage to realize an xy-movement of the interface with respect to a contra-interface (e.g. a connector such as a socket) of the battery powered vehicle. A linear actuator of the ACD is used to bring the interface and contra-interface together to allow charging. To this end an automatic connection device for charging an electric vehicle according to the present invention comprises an electrical interface, a planar motion stage comprising a first moving member, which first moving member is configured for moving the interface within a plane, a linear actuator configured for moving the interface in a direction essentially orthogonal to the plane, wherein the first moving member is configured to rotate the interface about a first axis essentially parallel to the direction and wherein the linear actuator comprises a threaded member for converting a rotational motion to a linear motion.

Such an arrangement has the advantage that the force and speed with which the connector is moved in the z direction is constant. Furthermore, it allows a low build height with a limited amount of moving parts. Additionally, a rotatable first moving member and a linear actuator comprising a threaded member for converting a rotational motion to a linear motion is not susceptible to malfunction due to pollutants and can easily be shielded from external influences such as debris or water.

[0007] Advantageously, a center of the interface is arranged at a first eccentric position from the first axis, because such an arrangement allows the translation of the interface within the plane when the first moving member is rotated. Preferably, the center is the geometrical center of the interface.

[0008] In a preferred embodiment, the planar motion stage comprises a second moving member configured to rotate the first moving member about a second axis essentially parallel to the direction. Two moving members nested offer more freedom with respect to available locations and/or orientations of the interface. In situations where the first axis is located at a second eccentric position from the second axis, the first moving member will be translated and rotated when the second moving member rotates. Alternatively, in situations where the first axis and the second axis coincide, the first moving member will only be rotated when the second moving member rotates.

[0009] Preferably, a first distance between the first axis and the first eccentric position is the same or smaller (e.g. half} than a second distance between the first axis and the second axis. Such an arrangement typically allows the smallest dimensions of the automatic connection device for reaching a defined range of locations for the electrical interface. Furthermore, it may be beneficial that the first distance and the second distance are at least the same or larger, because this allows a full circular area to be covered by the interface instead of an annular area.

[0010] Advantageously, the first moving member has a rotation angle about the first axis of at least 180 degrees and wherein the second moving member has a rotation angle about the second axis of at least 360 degrees to allow a full circular or annular area to be reached by the interface.

[0011] It may be beneficial that the first moving member comprises a first limiter for limiting the rotation of the first moving member and that the second moving member comprises a second limiter for limiting the rotation of the second moving member to prevent undue twisting or turning, and thereby enhance lifetime a power conduit (e.g. cable) of the automatic connection device that is connected to the interface. Preferably, the first limiter limits the rotation to essentially 180 degrees and the second limiter limits the rotation to essentially 360 degrees to allow a full circular or annular area to be reached by the interface.

[0012] In a preferred embodiment of an automatic connection device according to the invention, the linear actuator is arranged between the first moving member and the interface, and is configured to move the interface relative to the first moving member along the direction. Such an arrangement allows a lower amount of mass to be displaced compared to other embodiments according to the invention wherein the order in which features are connected is different. As a consequence, this reduces the actuation force requirements of the linear actuator. Additionally, it facilitates incorporating actuators (e.g. motors and gearings) in a part of the automatic connection device that is not displaced by the linear actuator along the direction. An additional advantage is that a smaller surface area of the displaced part comprising the interface reduces the requirements on the surface geometries surrounding the contra-interface.

[0013] To simplify shielding the inner parts of the automatic connection device from external influences (e.g. water, debris) it is generally preferred that each moving member has a surface with an essentially circular circumference, preferably such surface is disc shaped.

[0014] The treaded member may have various shapes and sizes. Preferably, it is hollow to accommodate a power conduit (e.g. cable). A resilient threaded member has the benefit that it can be compressed when the automatic charging device is not in use to reduce the build height and extended for mating the interface with a counterpart located for instance under a vehicle.

[0015] Advantageously, the threaded member is a hollow resilient member, such as a helical spring. The windings of such helical spring may form the treads of the treaded member. In situations where the helical spring has an essentially constant radius or an essentially constant winding diameter the treaded member be compressed such that adjacent windings abut one another, forming a tubular structure.

[0016] Alternatively, the helical spring may be tapered, wherein the diameter of the windings of the helical spring may be chosen such that the inner surface of a windings is larger than the outer surface of an adjacent winding (e.g. the inner surface of a winding abuts the outer surface of an adjacent winding) .

[0017] For shield the inner parts of the automatic connection device from external influences (e.g. water, debris) the helical spring may be equipped with a skirt attached to its windings and arranged coaxially with a longitudinal axis of the helical spring. Preferably, such skirt spans the area between adjacent windings when the helical spring is in an extended state.

[0018] The linear actuator may further comprise an annular member for engaging the treaded member (e.g. the windings of a helical spring), which is configured for rotating relative to the threaded member and converting the rotational motion to the linear motion. The benefit of using an annular member is that the void can then be used to allow passage of a power conduit, such as a cable. Alternatively, any other means such as a protruding member may be used for rotating relative to the threaded member.

[0019] To allow multiple vehicle models to be charged with an automatic connection device according to the present invention it is beneficial that the automatic connection device connects the interface with a contra-interface located at a well defined location of a vehicle, such as the underside of the vehicle, which is typically a relatively flat essentially horizontal surface. For mating such a contra-connector, the direction in which the interface is moved at least has a vertical directional component and preferably is essentially vertical.

[0020] It may be beneficial for the automatic connection device to further comprise a sensor for determining a misalignment within the plane between the interface and a contra-interface. Such misalignment information can be used for controlling the planar motion stage. It may also be used for informing the vehicle and controlling vehicle positioning.

[0021] Alternatively or additionally, the interface may comprise alignment features. For instance the interface may comprise a surface for mating a contra-interface having an alignment geometry for displacing the interface to allow mating connectors of the interface with connectors of a contra-interface. Examples of such geometries are conical, tapered, convex ar concave. The benefit of an interface comprising such alignment features is that the (final) alignment does not have to be actively controlled.

[0022] The automatic connection device may also comprise a further sensor for determining a third distance between the interface and a contra-interface along the direction. The third distance can be used for controlling the linear actuator. It may for instance be used as a safety feature to ensure that the interface or contra-interface are exposed to unnecessary loads. It may also be used to accelerate the process of making an automated connection, by allowing a faster movement for a larger third distance and slowing the movement down for a shorter third distance.

5 [0023] According to a second aspect of the invention the object is achieved by providing a charging station comprising an automated connection device according to the appended claims. Beneficially such charging station further comprises means for positioning a vehicle at the charging position.

[0024] According to a third aspect of the inventions the object is achieved by a use of an automated connection device according to the appended claims.

Brief description of the figures

[0025] Aspects of the invention will now be described in more detail with reference to the appended drawings, wherein same reference numerals illustrate same features and wherein:

[0026] Fig. 1 shows a cross-sectional view of an automated connection device according to an embodiment of the invention.

[0027] Fig. 2 shows a cross-sectional view along line A of structural elements of the automated connection device shown in Fig. 1.

[0028] Fig. 3A shows a sideview of an embodiment of a linear actuator in a contracted state for use in an automated connection device according to an embodiment of the invention.

[0029] Fig. 3B shows a sideview of an embodiment of a linear actuator in an extended state for use in an automated connection device according to an embodiment of the invention.

[0030] Fig. 4 shows schematic representations of the movement of planar motion stages in an automated connection device according to an embodiment of the invention.

[0031] Fig. 5 shows schematic representations of various positions of planar motion stages in an automated connection device according to an embodiment of the invention.

Description of embodiments

[0032] Referring to Fig. 1, the invention is related to an automated connection device 10. The device 10 comprises a first moving member 13 (e.g. an inner disk), a second moving member 12 (e.g. an outer disk), an electrical interface 11 (e.g. a connector) arranged on a base 14. The disks 12, 13 are arranged such that they can move the connector 11 in the x,y plane underneath a vehicle. The required position of the connector 11 is exactly underneath the counterpart in the vehicle such that preferably only a z-movement by means of a linear actuator is needed to mate the two connector parts. After mating the vehicle can be charged, for instance through a conductive path or via induction.

[0033] Both disks 12, 13 in the device 10 can preferably rotate independently of one another and independent of the base 14. The two disks 12, 13 can be actuated by any usual means, such as electric motors, which preferably drive the disks by a rack and pinion gear transmission.

[0034] For the outer disk 12 the gear rack 16 is connected to the outer disk 12 and the gear wheel 17 is connected to a motor 18 that is fixed to the base 14. This configuration eliminates the need of moving cables for controlling the outer disk rotation.

[0035] The inner disk 13 is actuated vice versa; the motor 19 with the gear wheel 20 is fixed to the inner disk 13 and the gear rack 21 is attached to the outer disk 12. As a result the inner disk 13 can rotate itself with respect to the outer disk 12. If the inner disk motor 19 is not powered the inner disk 13 follows the rotation of the outer disk 12. By attaching the motor 19 of the inner disk to the inner disk 13, all cables can be led from the base 14 to inner disk 13 directly without a connection to the moving outer disk 12. The inner disk 13 can comprise a control unit 22, e.g. a printed circuit board for the control of the motor 19, e.g. through PWM.

This local control and local PWM generation for the motor 19 eliminates the need of a long motor cable that might require shielding for EMC shielding purposes. Furthermore, other sensors and actuators close to the motor 19 might be needed, for example to open the connector cover.

[0036] The base 14 comprises a main control board 23 configured to control the current through the motors 18, 19 and can comprise a sensor interface to measure the position of the disks. Optionally, the main control board integrates the electronics for the electrical vehicle supply equipment. The latter would eliminate the need for an external wall box for safety and protection purposes. As a result, the system could be directly connected to the grid.

[0037] The base 14 can contain a system to detect the position of the vehicle.

Sensors 15 (e.g. transmitters, receivers) for this position estimation system can be placed at the corners of the base 14 to enable accurate position estimation by maximizing the distance between the sensors. The position estimation system can be based on various signals such as ultrasound signals or magnetic signals. These systems determine the position based on the difference between the received signals sensed by different sensors 15, or transmitted by different sensors. Hence, the distance between individual receivers, individual transmitters, or both result in a better position estimation. An additional position sensor 15 can be placed close to the connector 11 to reduce the effect of tolerances on the position device 10 itself.

[0038] Power transfer via the interface 11 can be realized by different means. An inductive coupling device can be realized with a very small airgap to enable a high efficiency power transfer. The advantage of this inductive coupling is that the cleanliness requirements for the connector are not strict. Compared to traditional inductive power transfer to charge a vehicle this system is more compact with a better defined magnetic path. However, the preferred power transfer method for this system is by means of a conductive path between ground station and vehicle. This conductive path improves the efficiency to almost 100%, is better scalable for higher charging power and is more reliable once the connector is mated.

[0039] The complexity of the positioning device 10 will be lower when the connector 11 has circular symmetry (not shown), i.e. orientation independent. This type of connector reduces the required number of degrees of freedom of the automatic connection device because the connector 11 does not have to be rotated. The connector 11 can be based on conductive rings at one side and conductive contactors at the contra-connector. By realizing a sliding contact when the connectors are mated, the connector 11 cleans itself and guarantees a proper conductive path. A mechanical (conical) self-centering feature can be added to the connector 11 to relieve the requirements on the connector positioning accuracy.

[0040] According to the invention, the x,y-movement, like the movement in a plane parallel to floor level, is realized by means of an inner disc 13 and an outer circular disc 12 with non-coinciding axes. That is, the inner disc 13 is placed eccentric relative to the outer disc 12. The connector or socket 11 is mounted off-center the inner disc 13. The inner disc 13 and the outer disc 12 can be rotated with respect to each other and both can be rotated relative to ground. By rotating both discs 12, 13 the connection point 11 can be moved in the xy-plane. More specifically, the inner disc 13 can turn about a first axis, as indicated by the arrows in Fig. 2A, to move the connector 11 in the x,y plane. The outer disk 12 can turn about a second axis, as indicated by the arrows in Fig. 2B, to move the inner disk 13 and the connector 11 in the x,y plane. By combining movement of the inner disc 13 and the outer disc 12 (as shown in Fig. 2C) the centre of the connector 11 can be positioned at any location inside circular area

27.

[0041] Referring to Fig. 3, the device according to the invention comprises an element 28 to move the connector 11 up towards the underside of a vehicle. A beneficial embodiment uses a linear actuator 28 for turning a rotational movement into a linear movement, preferably a spiral lift. Such linear actuators are very compact and allow a large stroke. The actuation system comprises a threaded member 30 for realizing a resilient tubular member 32 that is formed of continuous windings (see Fig. 3B), with the turns of each winding lying flat against each other in the retracted position of the tube 31 in its folded situation (see Fig. 3A).

[0042] The actuation system is actuated by means of an annular member 29 that engages the threaded member 30 and which is configured to be rotated relative to the threaded member 30. This relative rotation, for instance driven by a rotary motor that drives the gear wheel at the bottom of the device, results in a contraction 31 or extension 32 of the threaded member.

[0043] Using such a linear actuator in an automatic connection device equipped with planar motion stages 12, 13 (e.g. discs), for displacing the interface 11 orthogonal to the plane has some major advantages. The compact folded state makes it very suitable for this system to serve a wide range of vehicles having different ground clearances. It can provide a high force which makes mating of the connector 11 and its connector counterpart in the vehicle easy. Furthermore, the resilient member 30 can ensure that the mating force and the connection is maintained during charging, even when the height of the vehicle may change for instance due to passengers entering or leaving the car. In addition, the cylindrical column 32 that is realized between the device and the vehicle is a robust solution that can house the charging cable carrying the power for charging the electric vehicle. Such a charging cable may for instance be placed in a helical form inside the actuator 28. Such a helical cable can be extended when the actuator is extended 32 and be folded inside the actuation system when the actuator contracts to its folded state 31.

[0044] Beneficially, the threaded member comprises windings made from a strip that forms a continuous shield in the extended state 32 to keep the internals of the column clean and free of dirt and pollution such as leaves. Beneficially, the automatic connection device, comprises discs 12, 13 as planar motion stages and such a linear actuation system 28 with a circular shape that can easily be integrated in the disks and has the capability to carry a circular connector 11. Such a combination results in an automatic connection device 10 that can move a connector in x, y and z that is not sensitive to pollution. Alternatively, one or more planar motion stages, such as disk 13 or both disks 12 and 13 are placed on top of the linear actuator 28, and the connector may be provided on disk 13.

[0045] Fig. 4 shows for various positions of the planar motion stages 12, 13 the cabling in the device from the base 14 to the interface 11 that provides the electrical power required for charging the vehicle, driving the planar motion stages 12, 13 and driving the linear actuator 28. Such cabling can be realized by means of a flexible cable as illustrated by the dotted line in Fig 4. At one end this cable is attached to a first interconnection 24 to the base 14 and at the other end it is attached to a second interconnection 25 to the inner disk 13. The flexible cable has a loop 26 that rolls and unrolls at half the speed of the outer disk. This loop contains the over-length of the cable in order to make sure that all rotations of the disks 12, 13 can be covered. The inner disk 13 can rotate for instance between 0 and 180 degrees which is sufficient to cover all positions as long as the outer disk 12 can rotate between -180 and 180 degrees. The flexible cable is bend around the inner disk 13. When the inner disk 13 rotates clockwise the cable unrolls from this disk 13 and the loop 26 moves clockwise along the circumference of the outer disk 12.

[0046] The advantage of realizing a cable in this manner is the reduced number of dynamic bends and small bending radii of the cable; the cable only bends dynamically at the loop 26. The first interconnection 24 and the second interconnection 25 have a fixed bending radius. This is advantageous because the dynamic bends and the bending radius have impact on the lifetime of the cable.

[0047] Beneficially, the cable can be placed in a cable chain to protect the conductors of the cable and to realize a proper guiding inside the disks 12, 13. Another option is to mount the conductors on a simple plastic guide to realize a flat cable that is formed to follow the bends as illustrated in Fig. 4. The outer disk 12 may contain some kind of guide in the bottom and the cover to help guiding the cable/cable chain towards the edge of the disk.

Claims

Conclusions

An automatic connection device for charging an electric vehicle comprising: an electrical interface, a plane movement motion table comprising a first moving member, the first moving member being configured to move the interface in a plane, a linear actuator being configured for moving the interface in a direction substantially orthogonal to the plane, the first moving member configured to rotate the interface about a first axis substantially parallel to the direction, characterized in that the linear actuator has a a threaded member for converting a rotational motion to a linear motion.

Automatic connection device according to claim 1, wherein a center of the interface is placed at a first eccentric position with respect to the first axis, preferably the center is a geometric center of the interface.

The automatic connection device of claim 1 or 2 wherein the planar motion motion table comprises a second moving member configured to rotate the first moving member about a second axis substantially parallel to the direction.

The automatic connecting device of claim 3, wherein the first axis is located at a second eccentric position with respect to the second axis.

Automatic connecting device according to claim 3 or 4, wherein a first distance between the first axis and the first eccentric position is substantially equal to a second distance between the first axis and the second axis.

An automatic connector according to any of claims 3 to 8, wherein the linear actuator is disposed between the first moving member and the interface, and is configured to move the interface relative to the first moving member along the direction.

An automatic connector according to any one of the preceding claims, wherein each moving member has a surface with an essentially circular circumference, preferably the surface is disk-shaped.

An automatic connector according to any of the preceding claims, wherein the threaded member is a hollow resilient member, preferably a helical spring, more preferably a helical spring having a substantially constant radius.

An automatic connector according to any preceding claim, wherein the linear actuator comprises an annular member for engaging the threaded member configured to rotate relative to the threaded member and rotate the rotational movement toward the linear movement. to shape.

An automatic connector according to any of the preceding claims, wherein the direction has a vertical direction component and is preferably essentially vertical.

An automatic connector according to any of the preceding claims, further comprising a sensor for determining an in-plane misalignment between the interface and a counter-interface.

An automatic connection device according to any of the preceding claims, further comprising a further sensor for determining a third distance between the interface and a counter interface along the direction.

An automatic connector according to any one of the preceding claims, wherein the interface comprises a surface for coupling a counter interface with an alignment geometry for displacing the interface to allow coupling of connectors of the interface with connectors of a counter interface. preferably the geometry is conical, tapered, convex or concave.

Charging station for charging an electric vehicle, comprising an automatic connection device according to any one of the preceding claims.

Use of an automatic connection device or charging station according to any one of the preceding claims.