Charging infrastructure, vehicle contact unit, system and method for producing a conductive connection

Abstract

The invention relates to a charging infrastructure (12) for producing a conductive connection with a vehicle contact unit (16). The charging infrastructure (12) has a ground contact unit (18), which has a plate-type main body (26) and multiple contacts (30), which are arranged on a charging surface (28) of the main body (26), with which the vehicle contact unit (16) can come into contact. The multiple contacts (30) comprise at least one protective conductor contact (36), power contacts (32) and at least one control contact (40) for detecting a contacting. The at least one protective conductor contact (36) is hard wired. The power contacts (32) are associated with at least one potential layer (34). The at least one control contact (40) is formed separately from the power contacts (32) and separately from the at least one protective conductor contact (36). The invention also relates to a vehicle contact unit (16), a system (10) and a method for producing a conductive connection.

Description

[0001] Charging infrastructure, vehicle contact unit, system and method for establishing a conductive connection

[0002] The invention relates to a charging infrastructure for establishing a conductive connection with a vehicle contact unit. Furthermore, the invention relates to a vehicle contact unit for establishing a conductive connection with a ground contact unit. Furthermore, the invention relates to a system for establishing a conductive connection. Furthermore, the invention relates to a method for establishing a conductive connection between a ground contact unit and a vehicle contact unit.

[0003] In vehicles that are at least partially electrically powered, such as plug-in hybrid vehicles and fully electric vehicles, the batteries must be charged regularly, preferably after every trip. To do this, the vehicle is connected to a suitable power source, typically using a plug, such as a Type 2 plug, which must be manually inserted into a corresponding socket on the vehicle by a person. This also ensures that the plug is guided so that contact is made in a defined manner.

[0004] Ground contact units for vehicle battery charging systems, which are provided on the ground, are also known from the prior art, for example, WO 2019 / 052962 A1. The ground contact units can automatically establish a conductive connection with a corresponding vehicle contact unit provided on the vehicle to be charged in order to charge the vehicle. The vehicle contact unit can be provided on the underbody of the vehicle, where it moves downwards to establish electrical contact with the ground contact unit.

[0005] For example, the ground contact unit is designed as a so-called matrix charging pad, as shown in WO 2019 / 052962 A1. For this purpose, the ground contact unit comprises a plurality of contacts arranged in a matrix, wherein the contacts can be contacted by means of the vehicle contact unit to establish an electrical connection between the ground contact unit and the vehicle contact unit.

[0006] It can be provided that the vehicle contact unit is precisely aligned with the ground contact unit before a connector of the vehicle contact unit contacts the ground contact unit at a defined location. Alternatively, it can be provided that no guidance for the vehicle contact unit and / or no precise contact is provided, in which case a contact point of the connector of the vehicle contact unit on the ground contact unit must be detected. Depending on the contact point, the correspondingly assigned contacts of the ground contact unit are switched on to establish the electrical connection via these contacts.

[0007] However, the methods known to date for detecting the touchdown point are complicated and / or associated with high costs.

[0008] In this respect, the object of the invention is to provide a cost-effective way of detecting contact.

[0009] The object is achieved according to the invention by a charging infrastructure for establishing a conductive connection with a vehicle contact unit. The charging infrastructure comprises a ground contact unit having a plate-shaped base body and a plurality of contacts arranged on a charging surface of the base body against which the vehicle contact unit can come into contact. The plurality of contacts comprise at least one protective conductor contact, power contacts, and at least one control contact for detecting contact. The at least one protective conductor contact is hard-wired. The power contacts are assigned to at least one potential layer. The at least one control contact is formed separately from the power contacts and separately from the at least one protective conductor contact.

[0010] Furthermore, the object is achieved according to the invention by a vehicle contact unit for establishing a conductive connection with a ground contact unit. The vehicle contact unit has a plurality of contacts that can come into contact with a loading area of ​​the ground contact unit. The vehicle contact unit is movable translationally and / or rotationally in a plane parallel to the loading area. The plurality of contacts comprise at least one protective conductor contact, power contacts, and at least one control contact for detecting contact. The at least one protective conductor contact is hard-wired. The power contacts are assigned to at least one potential layer. The at least one control contact is designed separately from the power contacts and separately from the at least one protective conductor contact.

[0011] The basic idea of ​​the invention is to detect contact between the ground contact unit or the vehicle contact unit when the conductive connection is established by providing a separately designed control contact via which a control signal can be transmitted, thereby determining whether contact has been made between the vehicle contact unit and the ground contact unit, i.e., whether a conductive connection has been established. The control contact is designed separately from the power contacts and separately from the at least one protective conductor contact, so that a dedicated control signal can be used to detect the corresponding contact. In other words, the control signal is not a modulation or a high-frequency property of a signal that is provided and evaluated via one of the power contacts, but rather a dedicated control signal.However, it is conceivable that the control signal is a signal that is related to the protective earth (PE), i.e. PE-related.

[0012] In principle, at least one protective conductor contact is hard-wired, meaning that the corresponding protective conductor contact always serves as the protective conductor. It is therefore not possible for the protective conductor contact to be connected to a potential level intended for charging the vehicle, which could cause the protective conductor contact to function as a power contact.

[0013] It can be provided that the respective power contacts of the at least one potential level are assigned via at least one contact switch, which makes it possible to switch the individual power contacts to potential-free status. This is the case, for example, if not all power contacts contribute to the conductive connection when contact is established. The corresponding power contacts that contribute to more than just a conductive connection can therefore be switched to potential-free status via the contact switches.

[0014] One aspect provides that at least two power contacts are assigned to the same potential level. In this respect, more than one power contact is provided per potential level. The multiple power contacts connected to a potential level therefore represent a power contact level. The respective power contacts of a power contact level can be connected in groups to different potential levels by providing a corresponding switching unit. The switching unit can be configured to selectively connect power contacts of a first power contact level to a first potential level or to a second potential level. In this respect, all power contacts of a power contact level can be connected to a selected potential level via the switching unit. However, it is not possible to connect individual power contacts of an assigned power contact level to different potential levels.Furthermore, it can also be provided that power contacts of different power contact levels are not connected to a common potential level.

[0015] In particular, multiple potential levels are provided, with at least two power contacts assigned to each potential level. For example, two potential levels or four potential levels are provided. This depends on whether the application is a direct current (DC application) or an alternating current (AC application), in particular a three-phase application. With four potential levels, these can be formed by a neutral position (N) and three phase positions (L1, L2, L3).

[0016] A further aspect provides that the charging infrastructure comprises a monitoring circuit which is configured to monitor the contacting of the at least one control contact. In particular, the monitoring circuit can be configured to determine a touchdown position of the vehicle contact unit. The detection of the contacting merely ensures that there is contact with the vehicle contact unit somewhere on the charging surface of the ground contact unit, which can be determined accordingly by the monitoring circuit, which for this purpose recognizes the control signal running via the control contact. In a simple manner, all control contacts are supplied with a control signal, wherein a continuous connection via one of the control contacts is recognized upon contacting. However, it is not yet possible to determine the touchdown position, i.e. where the vehicle contact unit contacts the ground contact unit.

[0017] However, the monitoring circuit can also be configured to determine the placement position of the vehicle contact unit on the loading area of ​​the ground contact unit. This means that the position on the ground contact unit, in particular the loading area, at which the vehicle contact unit contacts the loading area can be determined. This is possible, for example, by applying the control signal to the control contacts individually or in groups in order to initially determine a rough area on the loading area of ​​the ground contact unit. Theoretically, the control contacts could also be applied with different control signals, with an evaluation of the control signal of the continuous connection then allowing a conclusion to be drawn about the placement position of the vehicle contact unit.

[0018] When monitoring by means of the monitoring circuit, it can also be determined whether a displacement of the vehicle contact unit relative to the ground contact unit and / or a rotation about an axis perpendicular thereto occurs, which results in a break in a control contact connection, i.e. the connection via the at least one control contact.

[0019] In particular, the at least one control contact and the power contacts are designed such that the connection via the at least one control contact is first broken before the connection via the power contacts is broken. This makes it possible for the monitoring circuit, which detects the breaking of the connection via the control contact, to trigger a shutdown device so that the corresponding power contacts are switched to a potential-free state before the connection via the power contacts is broken. This effectively prevents arcing or other avoidable effects.

[0020] The breaking of the conductive connection can be detected, in particular, in a direction perpendicular to the contact direction, i.e., in the plane in which the contact is made. It is determined whether the vehicle contact unit slips or shifts relative to the ground contact unit, which could cause the connection via the at least one control contact to break.

[0021] The shutdown device may comprise a main switch, such as a contactor. The main switch can then be opened to establish galvanic isolation. Alternatively or additionally, the shutdown device may comprise an electronic power control that reduces the applied potential to a non-critical value.

[0022] In other words, activating the shutdown device is equivalent to fault protection, as the state of the contact switches is checked. In the event of a fault, the main switch is opened to isolate the contacts and / or the applied potential is reduced. Alternatively or additionally, this is done if the existing contact is suddenly interrupted or is not terminated in a controlled manner.

[0023] In principle, the monitoring circuit can be provided as part of the charging infrastructure or in the vehicle, so that the corresponding monitoring can also be carried out on the vehicle side.

[0024] For example, the at least one control contact has a smaller surface area than the at least one protective conductor contact and / or than one of the power contacts, in particular than each of the power contacts. This ensures that, in the event of a relative displacement of the vehicle contact unit to the ground contact unit, the connection established via the at least one control contact is first broken before the connection via the power contacts and / or the connection via the protective conductor contact is broken. In this respect, the power contacts can be actively switched to potential-free mode before their connection is broken and / or an arc is generated.

[0025] According to a further aspect, the plurality of contacts comprise at least two control contacts, such that the charging infrastructure is configured to detect a contact orientation of the vehicle contact unit on the charging surface by means of the at least two control contacts. In particular, the plurality of contacts comprise two categories of control contacts that differ with regard to the control signals used, which are transmitted via the control contacts. For example, the control signals are inverted relative to one another and / or have different signal shapes, such that they can be differentiated from one another. Electrical faults such as short circuits or shunts can thus be reliably detected. It can also be provided that the corresponding control signals, which pass via the at least two different control contacts, are generated at different times from one another, whereby no valid signal would be generated in the event of any short circuits or shunts.In principle, the at least two control contacts located in a contacting area formed when the conductive connection between the vehicle contact unit and the ground contact unit is established ensure that the relative orientation of the vehicle contact unit to the ground contact unit can be determined. Based on the determined orientation, the power contacts can then be connected to corresponding potential levels to provide a wiring of the power contacts that is coordinated with respect to the determined relative orientation.

[0026] Furthermore, the at least one protective conductor contact can be formed by a continuous surface that provides a protective conductor plane that is penetrated by the power contacts and / or the at least one control contact. The corresponding protective conductor plane is also referred to as a PE plane (“PE plane”). In other words, a connection surface, for example a charging surface of the ground contact unit, can be largely formed by the protective conductor contact, wherein the corresponding power contacts are arranged in the plane formed by the protective conductor contact, in particular with an annular insulating region in order to electrically insulate the power contacts from the protective conductor contact, i.e. the corresponding protective conductor plane. Likewise, the control contact can be electrically insulated from the protective conductor plane by an annular insulating region.

[0027] One aspect provides that the contacts are designed such that the at least one control contact loses contact with the ground contact unit earlier than the power contacts and / or the at least one protective conductor contact during a relative movement of the vehicle contact unit to the ground contact unit. Alternatively or additionally, the at least one protective conductor contact can lose contact with the ground contact unit later than the power contacts during a relative movement of the vehicle contact unit to the ground contact unit. For example, the at least one control contact is smaller and / or shorter or has a smaller spring travel than the power contacts and / or the at least one protective conductor contact. Furthermore, it can be provided that the at least one control contact is smaller and / or shorter or has a smaller spring travel than the power contacts.This ensures that a connection established via the at least one control contact is broken first, before a connection at the power contacts or at the at least one protective conductor contact would be broken.

[0028] In the case of the vehicle contact unit, it can be provided in particular that the corresponding contacts are designed to be resilient, wherein the corresponding spring travels are different in order to ensure that the corresponding connections are broken at different times during a relative movement of the vehicle contact unit to the ground contact unit.

[0029] In principle, it can be provided that the at least one protective conductor contact is the last to lose contact during a relative movement of the vehicle contact unit to the ground contact unit. In other words, the contact via the at least one protective conductor contact is the last to be broken. For this purpose, it can be provided, among other things, that the at least one protective conductor contact is larger than the at least one control contact and / or the power contacts.

[0030] It can also be provided that the at least one protective conductor contact of the vehicle contact unit, in particular the center of the at least one protective conductor contact, is arranged on a circular line with a radius that is greater than a radius of a circular line on which the at least one protective conductor contact of the ground contact unit is arranged, in particular the center of the at least one protective conductor contact. Alternatively, it can be provided that the at least one protective conductor contact of the ground contact unit, in particular the center of the at least one protective conductor contact, is arranged on a circular line with a radius that is greater than a radius of a circular line on which the at least one protective conductor contact of the vehicle contact unit is arranged, in particular the center of the at least one protective conductor contact.This means that the connection via the protective conductor contacts is ultimately broken when the vehicle contact unit moves relative to the ground contact unit.

[0031] In principle, the respective protective conductor contact can be arranged on a circular line that has a different radius than neighboring power contacts and / or control contacts.

[0032] The object is further achieved according to the invention by a system for establishing a conductive connection, wherein the system has a vehicle contact unit with a plurality of contacts which comprise at least one protective conductor contact, power contacts and at least one control contact for detecting contact. The system further has a ground contact unit with a plate-shaped base body and a plurality of contacts which are arranged on a loading area of ​​the base body and comprise at least one protective conductor contact, power contacts and at least one control contact for detecting contact. The at least one protective conductor contact is hard-wired in each case, i.e. that of the vehicle contact unit and that of the ground contact unit. The respective power contacts, i.e. that of the vehicle contact unit and that of the ground contact unit, are assigned to at least one potential layer.The respective at least one control contact, i.e., that of the vehicle contact unit and that of the ground contact unit, is designed separately from the power contacts and separately from the at least one protective conductor contact. The vehicle contact unit is movable translationally and / or rotationally in a plane parallel to the loading area. The system comprises a monitoring circuit and a signal generator. Furthermore, the system is configured to apply a control signal to at least one control contact of the ground contact unit or the vehicle contact unit using the signal generator.The system is also configured to detect contact with the ground contact unit by means of the monitoring circuit, which is configured to receive and evaluate the control signal generated by the signal generator, which, in the contacted state, travels via the at least one control contact of the vehicle contact unit and / or the at least one control contact of the ground contact unit. With the corresponding system, it can therefore be determined, once a conductive connection has been established, whether the corresponding contact is present, particularly with regard to position and orientation, by passing the corresponding control signal via at least one of the control contacts and evaluating it accordingly.

[0033] One aspect provides that the contacts of the ground contact unit and the contacts of the vehicle contact unit are configured such that a connection via the protective conductor contact of the ground contact unit and the protective conductor contact of the vehicle contact unit remains intact even if the connections via the power contacts have already been broken due to a relative movement of the vehicle contact unit to the ground contact unit, in particular due to a relative movement of the vehicle contact unit to the ground contact unit. In particular, a relative displacement of the vehicle contact unit to the ground contact unit that is perpendicular to the contact direction is detected, provided this results in the connection established via the protective conductor contact being broken.

[0034] A further aspect provides that the at least one control contact of the ground contact unit and / or the at least one control contact of the vehicle contact unit are or are designed in such a way that a connection via the control contact of the ground contact unit and the control contact of the vehicle contact unit is broken upon a relative movement of the vehicle contact unit to the ground contact unit, before the connections via the power contacts are broken. For this purpose, the corresponding control contact can, for example, be designed to be smaller in area than the other contacts. In any case, it is ensured that the monitoring circuit first detects that the connection running via the control contact is no longer present, whereby the monitoring circuit can accordingly control a shutdown device which, for example, switches the power contacts to a potential-free state.

[0035] Furthermore, the object is achieved according to the invention by a method for establishing a conductive connection between a ground contact unit and a vehicle contact unit. The vehicle contact unit has a plurality of contacts, which comprise at least one protective conductor contact, power contacts, and at least one control contact for detecting contact. The ground contact unit has a plate-shaped base body and a plurality of contacts, which are arranged on a loading surface of the base body and comprise at least one protective conductor contact, power contacts, and at least one control contact for detecting contact. The at least one protective conductor contact is hard-wired in each case. The respective power contacts are assigned to at least one potential layer, wherein the respective at least one control contact is formed separately from the power contacts and separately from the at least one protective conductor contact.The vehicle contact unit is movable translationally and / or rotationally in a plane parallel to the loading area. The method comprises the following steps:

[0036] - applying a control signal to the at least one control contact of the ground contact unit or the vehicle contact unit and

[0037] Measuring whether the control signal is transmitted via a continuous connection comprising at least the control contact of the ground contact unit and / or the control contact of the vehicle contact unit.

[0038] In particular, the continuous connection can be provided between the control contact of the ground contact unit and the control contact of the vehicle contact unit. Alternatively, however, it can also be provided that, for example, the control contact of the ground contact unit forms a continuous connection with the protective conductor contact of the vehicle contact unit, whereby a continuous connection is also established. In a specific embodiment, this positioning also represents a desired contact of the ground contact unit, in which a charging current can be released, which can flow via the corresponding power contacts to charge the vehicle's battery.

[0039] One aspect provides that a contact area of ​​the vehicle contact unit is identified on the ground contact unit by rotating the vehicle contact unit relative to the ground contact unit and / or by connecting multiple control contacts of the ground contact unit individually and / or in groups. Multiple control contacts can be provided on the ground contact unit, which are connected individually or in groups, for example, to determine whether a conductive connection exists via one of the control contacts, which are connected accordingly. This initially allows a rough determination of the position of the vehicle contact unit on the ground contact unit.A further aspect provides that an orientation of the vehicle contact unit relative to the ground contact unit is identified by applying different control signals to at least two control contacts of the ground contact unit or the vehicle contact unit. Once a corresponding contact with the ground contact unit by the vehicle contact unit has been identified, in particular also the position of the contact area, the relative orientation can be determined. For this purpose, two different control signals are applied to two control contacts located in the contact area. This then makes it possible to determine the corresponding orientation of the vehicle contact unit relative to the ground contact unit. Based on the detected orientation, the corresponding power contacts can then be connected to specific potential levels in order to ensure an optimal charging process.

[0040] Furthermore, a cleaning check can be performed by applying a low-voltage protection voltage to at least one control contact of the ground contact unit, whereby an insulation check is performed between two contacts of the ground contact unit. This can determine whether the insulation distance between two contacts is maintained, i.e., whether there is any contamination that would prevent this.

[0041] In principle, touch protection monitoring can be implemented to ensure that unintentional contact with accessible contacts is possible. Touch protection monitoring is performed continuously during conductive charging. However, it can also be configured to be performed immediately before the charging process.

[0042] For this purpose, for example, it is provided that, during continuous contact protection monitoring, the respective switching positions of the contact switches assigned to the power contacts that are not contacted are monitored. These are the power contacts that do not belong to a subset of the contacted contacts, which is why they are accessible from the outside. The subset of the contacted contacts corresponds to the contact area. The subset of the multiple contacts is therefore assigned to a contact area of ​​the loading area, which is covered by a component of the vehicle contact unit when a conductive connection is established between the ground contact unit and the vehicle contact unit.The corresponding subset, i.e. the number of multiple contacts located in the contacting area, depends on the size of the ground contact unit and / or the size of the corresponding component of the vehicle contact unit, which interacts with the contacts of the ground contact unit for the conductive connection, for example a connector of the vehicle contact unit.

[0043] The accessible contacts can also be referred to as exposed contacts because they are not covered by the vehicle contact unit when the conductive connection is established. Touch protection monitoring via the switch positions of the contact switches checks whether the corresponding power contacts are switched to potential-free mode, as intended for exposed power contacts—i.e., the power contacts that do not form a conductive connection with the vehicle contact unit.

[0044] Alternatively or additionally, continuous touch protection monitoring can consist of continuously monitoring whether the previously established conductive connection is maintained or whether the established conductive connection has been broken. For this purpose, it may be sufficient to check at least one of the contacts in the subset, since this was previously contacted. In principle, the at least one contact in the subset used for continuous touch protection monitoring can be the control contact through which the control signal is transmitted, which is monitored accordingly.

[0045] The contact protection monitoring can be carried out using the monitoring circuit, which monitors the switching position of the contact switches and / or the continuous contacting of the corresponding contact of the subset, i.e. the control contact.

[0046] In an extreme example, it may be intended that all contacts of the ground contact unit are occupied, meaning that there are no exposed contacts in the contacted state. Accordingly, the subset of the multiple contacts can correspond to all contacts of the ground contact unit. Typically, however, the ground contact unit has more contacts than the contacts required for the conductive connection between the ground contact unit and the vehicle contact unit. This ensures, among other things, that the vehicle does not have to come to a stop precisely over a specific area of ​​the ground contact unit, thus providing greater flexibility.The component of the vehicle contact unit that covers the contact area can be a movable part of the vehicle contact unit, for example, a movable charging nozzle or similar, which is moved from the underbody of the vehicle toward the ground contact unit to establish the conductive connection. The movable part of the vehicle contact unit can also be generally referred to as a connector.

[0047] In principle, a defined control signal can be fed in via the at least one control contact of the vehicle contact unit or the ground contact unit, which interacts with an associated contact of the other unit, for example a control contact, thereby closing an electrical circuit in which the corresponding control signal can be evaluated.

[0048] If two control contacts are provided on the vehicle contact unit and / or the ground contact unit, which are also supplied with different control signals, the orientation of the vehicle contact unit relative to the ground contact unit can be determined if the conductive connection is present, i.e., the contact orientation. Regardless, two control contacts make it possible to create two channels, thus creating corresponding redundancy.

[0049] The control signal can be a safety extra-low voltage.

[0050] In particular, the contacts are designed and arranged in such a way that in a contacting area at least two control contacts of the vehicle contact unit and / or two control contacts of the ground contact unit are always part of the contacted contacts.

[0051] Furthermore, the respective contacts are arranged and dimensioned in such a way that no short circuit occurs when contact is established. This also applies if the vehicle contact unit shifts relative to the ground contact unit, particularly in the contact plane. Further advantages and features of the invention will become apparent from the following descriptions and drawings, to which reference is made. The drawings show:

[0052] Figure 1 shows a schematic overview of a system according to the invention with a charging infrastructure according to the invention and a vehicle contact unit according to the invention,

[0053] Figure 2 is a schematic plan view of a ground contact unit of a charging infrastructure according to the invention according to an embodiment,

[0054] Figure 3 is a schematic plan view of a floor contact unit of a charging infrastructure according to the invention according to a second embodiment,

[0055] Figure 4 is a schematic representation of the electrical connection of the power contacts in a charging infrastructure according to the invention, and

[0056] Figure 5 is a schematic overview of a sequence illustrating a method according to the invention for establishing a conductive connection between a ground contact unit and a vehicle contact unit.

[0057] Figure 1 shows a system 10 comprising an electric charging infrastructure 12 and an at least partially electrically powered vehicle 14. The system 10 may also be referred to as a vehicle battery charging system.

[0058] The vehicle 14 has a vehicle contact unit 16, which can establish a conductive connection with a ground contact unit 18 of the electrical charging infrastructure 12 in order to charge a battery of the vehicle 14 (not shown in detail here).

[0059] The electrical charging infrastructure 12 has a monitoring circuit 20 and a shutdown device 22, which can be fully integrated into the ground contact unit 18. Alternatively, the monitoring circuit 20 can be arranged partially in the ground contact unit 18 and partially in a monitoring unit 24 that is designed separately from the ground contact unit 18. Furthermore, it can be provided that the monitoring circuit 20 and the shutdown device 22 are both arranged entirely in the separately designed monitoring unit 24.

[0060] The separately designed monitoring unit 24 is therefore optional, which is why it is shown in dashed lines in Figure 1. Likewise, the monitoring circuit 20 and the shutdown device 22 are shown in dashed lines, as their respective positions may vary depending on the design. In any case, the separately designed monitoring unit 24 would be electrically connected to the ground contact unit 18, as indicated in Figure 1.

[0061] Alternatively, it can also be provided that the monitoring circuit 20 and / or the shutdown device 22 are or are provided on the vehicle side.

[0062] In Figure 2, the ground contact unit 18 of the charging infrastructure 12 is shown in a plan view according to one embodiment.

[0063] The ground contact unit 18 comprises a plate-shaped base body 26 having a loading surface 28 that is exposed prior to establishing the conductive connection. The loading surface 28 is an exposed loading surface when contact is established between the ground contact unit 18 and the vehicle contact unit 16.

[0064] However, the loading area 28 can generally be covered by a cover (not shown here) when not in use, so that the loading area 28 is protected from environmental influences, among other things. The corresponding cover can be removed manually or automatically, making the loading area 28 freely accessible.

[0065] On the loading surface 28, several contacts 30 are provided, which are different contact types.

[0066] In any case, the contacts 30 include, among other things, a plurality of power contacts 32, which are used for charging the battery of the vehicle 14. When charging the vehicle 14, in particular when charging the battery of the vehicle 14, a charging current flows through at least some of the power contacts 32. For this purpose, the corresponding power contacts 32 are generally assigned to at least one potential layer 34, as will be explained below.

[0067] In the illustrated embodiment, the ground contact unit 18 is designed as a three-phase ground contact unit 18, which means that the individual power contacts 32 can be assigned to four different potential positions 34, namely the neutral position N and the phase positions L1, L2, and L3. The neutral position N is also referred to as the neutral conductor. These are therefore the corresponding potential positions N, P1, P2, and P3.

[0068] As can be seen from Figure 2, a corresponding three-phase connection 35 is therefore provided, in particular at the ground contact unit 18.

[0069] The power contacts 32 are therefore divided into power contact levels P1, P2, P3, P4 or assigned to the power contact levels, which are also referred to as “pin layers”.

[0070] In this respect, there are four types of power contacts 32: first power contacts 32-1, which are assigned to the first power contact level P1, second power contacts 32-2, which are assigned to the second power contact level P2, third power contacts 32-3, which are assigned to the third power contact level P3, and fourth power contacts 32-4, which are assigned to the fourth power contact level P4. This is clearly shown in Figure 4, which will be referred to below when describing the interconnection of the power contacts 32.

[0071] It is already clear from Figure 2 that the four types of power contacts 32 are arranged in a rectangle, in particular in a rectangle on the loading surface 28.

[0072] In the exemplary embodiment shown, the first power contact 32-1 is provided in an upper right corner of the rectangle, whereas the second power contact 32-2 is provided in the lower right corner of the rectangle. The third power contact 32-3 is provided in a lower left corner of the rectangle, whereas the fourth power contact 32-4 is provided in an upper left corner of the rectangle. In this respect, the four types of power contacts 32 together form the rectangle in the corresponding plane. In addition to the power contacts 32, the contacts 30 also comprise at least one protective conductor contact 36, i.e. a PE contact. In the embodiment shown in Figure 2, a plurality of protective conductor contacts 36 are provided, which are arranged separately and insulated from the power contacts 32 on the charging surface 28.

[0073] Furthermore, it can be seen from the embodiment shown in Figure 2 that the protective conductor contacts 36 are each arranged in the center of the rectangles.

[0074] The rectangles are designed, in particular, as squares, so that the protective conductor contact 36 arranged in the center has the same distance from each of the power contacts 32. In this respect, a centered square pattern is provided in Figure 2 with regard to the power contacts 32 and the protective conductor contacts 36.

[0075] As an alternative to the embodiment shown in Figure 2, the ground contact unit 18 can have a continuous protective conductor plane 38, which accordingly essentially corresponds to the area of ​​the base body 26 or the base area of ​​the loading area 28, as shown in Figure 3.

[0076] The individual power contacts 32 then break through the corresponding protective conductor level 38, wherein the power contacts 32 are each arranged insulated from the protective conductor level 38, for example by annular insulating sections 39 which insulate the power contacts 32 from the protective conductor level 38.

[0077] In addition, the contacts 30 can in principle comprise at least one control contact 40, which is used to carry out a contact check, i.e. to determine whether the vehicle contact unit 16 contacts the ground contact unit 18, which will be discussed below.

[0078] In the embodiments shown in Figures 2 and 3, several control contacts 40 are provided.

[0079] In principle, the control contacts 40 and / or the protective conductor contacts 36 can be designed as magnetic contacts 41, i.e., they can be magnetizable. This makes it possible for the conductive connection established to occur only in a defined manner, namely such that at least one magnetic contact 41 of the vehicle contact unit 16 couples with a magnetic contact 41 of the ground contact unit 18.

[0080] The defined connection is ensured because the magnetic contacts 41 are each arranged centrally in an associated rectangle, in particular a square, in whose corners a type of power contact 32 is provided, i.e., a first power contact 32-1, a second power contact 32-2, a third power contact 32-3, and a fourth power contact 32-4. Consequently, either a protective conductor contact 36 or a control contact 40 can be provided in the center of the respective rectangle.

[0081] In particular, the contacts 30 are generally distributed on the loading surface 28 and arranged relative to one another in such a way that at least two control contacts 40 are located in a contact area A of the loading surface 28, which is covered by the vehicle contact unit 16 when the conductive connection is established. The orientation in which the ground contact unit 18 has been contacted can then be determined via the two control contacts 40 in the contact area A.

[0082] By knowing the geometry of the vehicle contact unit 16, it is also possible to determine which contacts 30 have been contacted, i.e. which of the contacts 30 belong to the subset of the contacted contacts 30 that are located in the contact area A of the loading area 28.

[0083] Based on this information, the corresponding power contacts 32 can then be switched in order to assign or connect a specific potential position 34 to the different power contact levels P1 to P4.

[0084] Figure 4 shows, using an example embodiment, how the power contacts 32 are connected. This generally applies to the connection of the power contacts 32 of the vehicle contact unit 16 as well as to the connection of the power contacts 32 of the ground contact unit 18.

[0085] The individual power contacts 32 can each be connected to a corresponding power contact level P1 to P4 via contact switches 42, so that the individual power contacts 32 can be switched on or off via the contact switches 42. This makes it possible to only switch on the power contacts 32 of a corresponding potential level 34 that are located in contact area A, so that exposed power contacts 32 are potential-free.

[0086] Figure 4 further shows that the respective contact switches 42 are designed as mirror contacts, so that the contact switches 42 have a main contact 44 and a monitoring contact 46. Due to the mirror contact design, it is ensured that the main contact 44, which functions as a relay, is mechanically coupled to the monitoring contact 46, so that the respective switching positions of the main contact 44 and the monitoring contact 46 are mutually dependent or interdependent. However, the main contact 44 and the monitoring contact 46 are galvanically isolated from one another, so that both contacts 44, 46 are not assigned to a common circuit. Rather, both contacts 44, 46 are assigned to different circuits that are independent of one another and also galvanically isolated from one another.

[0087] In this respect, there is no switching position of the contact switch 42 in which a closed circuit is formed in which both the main contact 44 and the monitoring contact 46 are integrated, so that a current could flow through both contacts 44, 46 of the contact switch 42. The main contact 44 is, as shown in Figure 4, designed as a normally open contact, i.e., an NO contact, whereas the monitoring contact 46 is designed as a normally closed contact, i.e., an NC contact.

[0088] Figure 4 therefore shows the initial position of the contact switches 42, since the contact switches 42 are each in a corresponding switching position in which the main contacts 44 are open, so that no current flow to the power contacts 32 is possible. In other words, the power contacts 32 are not connected to any potential layer 34, thus ensuring contact protection.

[0089] The corresponding contact protection can be monitored by the monitoring circuit 20, among other things, monitoring the respective switching position of the monitoring contacts 46 of the corresponding contact switches 42. Monitoring takes place at least for the contact switches 42 that are assigned to power contacts 32 that are not contacted when the conductive connection between the ground contact unit 18 and the vehicle contact unit 16 is present, i.e., for power contacts 32 that are not part of the subset of the multiple contacts 30 of the ground contact unit 18 that are contacted.

[0090] The monitoring circuit 20 controls the shutdown device 22 if the monitoring circuit 20 detects that an incorrect switching position is present at one of the monitoring contacts 46, which results in one of the main contacts 44 also having an incorrect switching position, since the monitoring contacts 46 and the main contacts 44 are mechanically coupled to one another.

[0091] The incorrect switching position corresponds to an open switching position of the monitoring contact 46, which is accompanied by a closed switching position of the associated main contact 44, which would mean that a freely accessible power contact 32 would be assigned to a potential position 34, although this is not desired since the corresponding power contact 32 is exposed.

[0092] The shutdown device 22 changes its state due to the control by the monitoring circuit 20, which can be accompanied by a complete shutdown or complete disconnection. In other words, the shutdown device 22 can be designed such that a galvanic isolation of all power contacts 32 is performed, whereby all power contacts 32 would be switched to a potential-free state.

[0093] In this respect, the shutdown device 22 can comprise a main switch 46 or a contactor, which carries out the corresponding galvanic isolation.

[0094] Alternatively, the shutdown device 22 can comprise an electronic power control 50, which is provided to reduce the voltage associated with the potential layer 34 accordingly, so that the applied voltage is limited to a non-critical value, thereby ensuring contact protection. In other words, the voltage applied to the respective power contact 32, which is coupled to the incorrectly closed main contact 44 of the contact switch 42, is so low that no danger exists. Furthermore, Figure 4 shows that an input interface 52 is provided, which is associated with the terminal 35 and the potential layers 34.

[0095] Furthermore, an output interface 54 is provided which is connected to the power contacts 32, in particular the power contact levels P1 to P4.

[0096] In addition, a switching unit 56 is provided, which is provided between the input interface 52 and the output interface 54.

[0097] The switching unit 56 has a plurality of switches 58 which are basically designed to selectively switch the power contacts 32, each belonging to a power contact level P1 to P4, together between a first potential position 34 and a second potential position 34, for example between the neutral position N and the first phase L1.

[0098] This occurs in particular depending on the orientation of the vehicle contact unit 16 to the ground contact unit 18 determined via the control contacts 40.

[0099] The switching unit 56 ensures, for example, that at least the first power contacts 32-1, i.e. the power contacts 32 assigned to the first power contact level P1, can be connected optionally to the first potential position 34 (neutral position N) or to the second potential position 34 (first phase position L1).

[0100] In the embodiment shown in Figure 4, the switching unit 56 is designed such that all power contact levels P1 to P4, i.e. the respective power contacts 32 in groups, can be selectively connected to each of the existing potential levels 34, so that maximum flexibility is ensured.

[0101] The section shown in Figure 4 shows the four different types of power contacts 32, i.e., a first power contact 32-1, a second power contact 32-2, a third power contact 32-3, and a fourth power contact 32-4. In other words, power contacts 32 are shown that are assigned to the first power contact level P1, the second power contact level P2, the third power contact level P3, and the fourth power contact level P4, or are connected to them via the corresponding contact switches 42.

[0102] In principle, the switches 58 - like the contact switches 42 - can also be designed as mirror contacts, so that the switches 58 have a main contact 60 and a monitoring contact 62.

[0103] In contrast to the power contacts 32, the at least one protective conductor contact 36 is hard-wired, which means that the at least one protective conductor contact 36 or the protective conductor level 38 is fixed, i.e. cannot be connected to one of the potential layers 34.

[0104] This also applies to the control contacts 40, which are also hard-wired.

[0105] As already explained above, the at least one control contact 40 is provided to carry out a contact check, i.e. to determine whether the vehicle contact unit 16 has contacted the ground contact unit 18.

[0106] In particular, the contacts 30 are generally distributed, dimensioned and / or arranged relative to one another in such a way that at least two control contacts 40 are located in the contacting area A, which is covered by the vehicle contact unit 16 when the conductive connection is established, as can be seen from Figures 2 and 3.

[0107] Figure 5 shows a sequence of steps that are performed to initiate and terminate a charging process.

[0108] To prepare for the charging process, a self-test of the power contacts 32 can first be performed to ensure that the contact switches 42 of all power contacts 32 are open. This can be performed at the beginning to ensure that the ground contact unit 18 and / or the vehicle contact unit 16 are fundamentally in a state to be able to carry out a charging process. For this purpose, the positions of the contact switches 42, in particular the monitoring contacts 46, can be monitored using the monitoring circuit 20.

[0109] Furthermore, the preparation phase may include a compatibility check, during which communication takes place between the ground contact unit 18 and the vehicle contact unit 16 of the vehicle to determine whether the two contact units 16, 18 can even perform a charging process with each other. Corresponding signals are exchanged to determine whether the contact units 16, 18 are compatible with each other.

[0110] Subsequently, during the preparation phase, positioning can occur, in which the vehicle 14 is positioned via the ground contact unit 18 or relative thereto by emitting appropriate signals so that, for example, a driver of the vehicle 14 parks the vehicle 14 as precisely as possible via the ground contact unit 18, thereby establishing a conductive connection. The signals can be optical and / or acoustic signals. In an at least partially autonomously operated vehicle, positioning can also occur automatically. In any case, this makes it possible to minimize the size of the ground contact unit 18.

[0111] The vehicle 14 or the vehicle contact unit 16 will then send a charging request to the electrical charging infrastructure 12, in particular the ground contact unit 18. The electrical charging infrastructure 12 processes the charging request accordingly. If the result is positive, this is communicated to the vehicle 14 or the vehicle contact unit 16, whereupon the charging process can be initiated.

[0112] For this purpose, the conductive connection between the vehicle contact unit 16 and the ground contact unit 18 is first established by moving at least one component of the vehicle contact unit 16, for example a connector, toward the ground contact unit 18, whereby it comes into contact with the loading surface 28 of the ground contact unit 18 in some areas, so that at least a subset of the plurality of contacts 30 of the ground contact unit 18 is contacted. To determine this, a contact check is performed to determine whether contacts 30 of the ground contact unit 18 are contacted.

[0113] The contact check is performed via the control contacts 40. For this purpose, at least one control signal, for example a low-voltage protection voltage, is applied to the control contacts 40, in particular to at least one of the control contacts 40. The control signal can be generated by a signal generator 64, which is provided, for example, on the vehicle side, for example as part of the vehicle contact unit 16. Alternatively, the signal generator 64 can be provided on the infrastructure side, for example as part of the charging infrastructure 12.

[0114] In addition, it is measured whether the control signal is transmitted via a continuous connection that includes at least the control contact 40 of the ground contact unit 18 and / or the control contact 40 of the vehicle contact unit 16 to which the control signal has been applied. The monitoring circuit 20 can be used accordingly for this purpose.

[0115] In addition, it can be determined which of the corresponding contacts 30 are connected by switching the control contacts 40 individually and / or in groups. If it is determined that a continuous connection exists at one of the control contacts 40, it has been determined that the corresponding control contact 40 is connected.

[0116] By selectively switching the control contacts 40, the contact area A of the vehicle contact unit 16 on the ground contact unit 18 can be identified.

[0117] Subsequently, the environment of the determined control contact 40 can also be switched on in order to check which (neighboring) control contacts 40 are contacted.

[0118] This ensures that a landing position of the vehicle contact unit 16 is determined, since knowledge of the contacted control contacts 40 also allows the determination of which other contacts 30 are contacted. This takes advantage of the fact that the magnetic contacts 41 are provided, whereby the vehicle contact unit 16 contacts the ground contact unit 18 only in a defined manner, namely such that a coupling via two magnetic contacts 41 is present, which is also referred to as "snap-in."

[0119] The control contacts 40 can also carry different control signals, which can additionally determine the contact orientation of the vehicle contact unit 16 with respect to the ground contact unit 18. This can also be done using the monitoring circuit 20.

[0120] The charging infrastructure 12 and / or the vehicle contact unit 16 are or are accordingly configured to detect a contact orientation of the vehicle contact unit 16 on the charging surface 28 by means of the at least two control contacts 40.

[0121] Depending on the contact check carried out and the contact position determined thereby, i.e. the contact position, as well as the optionally determined contact orientation, the contacted power contacts 32 could then be connected to certain potential levels 34, in particular via the corresponding switching unit 56.

[0122] However, during the testing phase, a protective conductor test may still be carried out, in which a test current is passed through at least one contact 30 of the plurality of contacts 30 in order to determine a contact quality of the existing conductive connection between the vehicle contact unit 16 and the ground contact unit 18.

[0123] For this purpose, the vehicle 14 can comprise a current generator or a signal generator which provides the test current which is conducted via one of the contacts of the vehicle contact unit 16 to a contact 30 of the contacts 30 of the ground contact unit 18 coupled thereto.

[0124] For example, one of the power contacts 32 can be used, which is coupled to a corresponding power contact 32 of the vehicle contact unit 16, wherein the corresponding power contact 32 of the ground contact unit 18 has been switched to the protective conductor level, which corresponds to the level of the protective conductor contact 36. For this purpose, a relay can be provided, via which the corresponding contact 30 is connected to the protective conductor level.

[0125] A resistance can then be measured to determine the contact quality. The measured resistance should not exceed 0.1 Ω, thus providing a protective conductor resistance threshold of 0.1 Ω. The test current used should have a current of at least 200 mA. Alternatively, the test current can also be provided by the ground contact unit 18.

[0126] A further step involves conducting an insulation test during the inspection to determine that there are no leakage or shunt currents or similar between contacts 30 or other areas of the ground contact unit 18. The insulation test can generally be performed between two contacts 30 by applying a test voltage and measuring an insulation resistance, which is compared to a predetermined insulation resistance threshold. For example, the test voltage is at least 500 V. The insulation resistance threshold is, for example, 0.25 MΩ.

[0127] The two contacts 30 used for the insulation test can be adjacent contacts on the charging surface 28, in particular two contacts 30 of the subset of contacts 30 that are contacted when the conductive connection is present. An (unintentional) conductive connection is most likely to occur between adjacent contacts 30, for example, via an object, dirt, or moisture. In particular, the insulation test is performed between two power contacts 32. Alternatively or additionally, it can be provided that the insulation test is performed between at least one line contact 32 and the at least one protective conductor contact 36. The insulation test can also be performed between at least one line contact 32 and the control contact 40.

[0128] During the insulation test, the insulation can also be measured from a contact 30 of the subset to a point on the loading surface 28 of the base body 26. In principle, the insulation test can only be performed if it has previously been determined that at least a subset of the multiple contacts 30 is actually contacted, i.e., that a conductive connection exists.

[0129] Furthermore, the protective conductor test can also only be performed if it has previously been determined that a conductive connection exists, i.e., at least a subset of the multiple contacts 30 is contacted. Furthermore, the protective conductor test can also only be performed if the insulation test has previously been successfully performed.

[0130] The insulation test can also be considered part of a cleaning test, in which a low-voltage protection voltage is applied to at least one control contact 40 of the ground contact unit 18. The insulation test is then performed between two contacts 30 of the ground contact unit 18.

[0131] Once the verification has been performed and all verification steps have been successfully completed, the charging process can begin.

[0132] As previously explained, the power contacts 32, which do not belong to the subset of the contacted contacts 30, have already been switched to potential-free via the contact switches 42, which was also checked during the self-test during preparation.

[0133] In this respect, only the power contacts 32 of the corresponding potential level 34 are connected, which belong to the subset of the contacted contacts 30.

[0134] This process relies on the information obtained during the contact verification, since only those power contacts 32 that are actually contacted are connected to a potential level 34 via the associated contact switches 42 to ensure contact protection. This information is obtained based on the recorded contact position. The respective potential level 34 is also selected based on the contact orientation determined during the contact verification.

[0135] As explained above, the switching unit 56, in particular the switches 58, is configured such that the power contact levels P1, P2, P3, P4 can be connected to the different potential positions 34, for example, the neutral position N or one of the phase positions L1, L2, L3. This allows setting whether the neutral position N or one of the phase positions L1, L2, L3 is present in the upper right corner of a respective rectangle.

[0136] This can apply analogously to all corners of the rectangle, provided that the switching unit 56 is designed as shown in Figure 4. Therefore, the respective potential position of the corners of the rectangle can be adjusted based on the detected contact orientation.

[0137] In particular, the power contact levels P1, P2, P3, P4 are first connected to the different potential levels 34 before the correspondingly contacted power contacts 32 are connected to the power contact levels P1, P2, P3, P4 via the contact switches 42, i.e. are placed on a potential.

[0138] After the electrical connection between the contacted power contacts 32 and the corresponding potential layers 34 has been established, a charging current can flow from the ground contact unit 18 via the vehicle contact unit 16 into the battery of the vehicle 14, whereby the battery is charged accordingly.

[0139] During the charging process, continuous touch protection monitoring takes place, as already explained. This determines whether only the contacted power contacts 32 of a corresponding potential level 34 are actually connected.

[0140] Furthermore, it is checked whether the existing contact breaks during the charging process by continuously monitoring a contact 30 of the subset of the contacted contacts, namely the control contact 40.

[0141] Among other things, it is provided that at least one control contact

[0142] 40 has a smaller area than the at least one protective conductor contact 36 and / or than one of the power contacts 32, in particular than each of the power contacts 32. In this respect, the connection via the at least one control contact 40 would first be broken before the connections via the power contacts 32 and / or the connection via the protective conductor contact 36 are broken or are broken.

[0143] If it is determined that the contact protection is no longer guaranteed, i.e., the connection via at least one control contact 40 has been broken, the shutdown device 22 is activated by the monitoring circuit 20, whereby either the main switch 48 is opened to establish galvanic isolation, and / or the electronic power control 50 reduces the corresponding potential until a non-critical voltage value is reached. The non-critical value can be a voltage that is safe, in particular a voltage below 25 V AC, i.e., 25 V AC, or 60 V DC.

[0144] Alternatively or in addition to the smaller area of ​​the at least one control contact 40, it can also be provided that the control contacts 40 are designed with a shorter spring travel than the power contacts 32 and / or the at least one protective conductor contact 36, in particular the control contacts 40 of the vehicle contact unit 16. Likewise, the control contacts 40 can be shorter than the power contacts 32 and / or the at least one protective conductor contact 36.

[0145] In any case, this ensures that in the event of a relative displacement of the vehicle contact unit 16 to the ground contact unit 18, the connection established via the at least one control contact 40 is first broken before the connection via the power contacts 32 and / or the connection via the protective conductor contact 36 is broken. The power contacts 32 can thus be actively switched to potential-free mode or the voltage level can be actively reduced before their connection is broken and / or an arc is generated.

[0146] The breaking of the conductive connection is detected, in particular, in a direction perpendicular to the contact direction, i.e., in the plane in which the contact is established. Accordingly, it is determined whether the vehicle contact unit 16 slips or shifts relative to the ground contact unit 18, causing the connection via the at least one control contact 40 to break, particularly first. If no unwanted breaking of the conductive connection is detected, the charging process is continued to completion. The contact monitoring takes place continuously, as already explained above.

[0147] After the charging process has been completed, the conductive connection between the vehicle contact unit 16 and the ground contact unit 18 is actively separated.

[0148] For this purpose, the previously connected power contacts 32, which belong to the subset, are first switched to potential-free mode by controlling the corresponding contact switches 42.

[0149] In addition, the shutdown device 22 can also be controlled accordingly, for example, to implement galvanic isolation via the main switch 48. This creates redundancy. In addition, it can be checked again whether the power contacts 32 are all potential-free by monitoring the associated monitoring contacts 46 via the monitoring circuit 20.

[0150] The conductive connection is then released by disengaging the vehicle contact unit 16 so that there is no longer any contact with the ground contact unit 18. The vehicle 14 can then leave the electrical charging infrastructure 12.

[0151] Finally, a further self-test can be carried out by determining whether all power contacts 32 are in their potential-free state, i.e. whether the associated contact switches 42 are all in the non-current-carrying state, which occurs when the corresponding main contacts 44 are open or the monitoring contacts 46 are closed.

[0152] In principle, the self-test can of course also be performed at other times. Self-tests can therefore be performed at multiple times, for example, cyclically, to continuously check the readiness of the electric charging infrastructure 12, in particular that of the ground contact unit 18.

[0153] This ensures that the vehicle 14 can be efficiently electrically charged by establishing a conductive connection. At the same time, appropriate safety precautions are taken by checking whether the ground contact unit 18 is in a condition suitable for a charging process.

[0154] The sequence shown in Figure 5 and the associated method can in principle be carried out by the electrical charging infrastructure 12, which is set up accordingly for this purpose.

[0155] In principle, the vehicle contact unit 16 is movable translationally and / or rotationally in a plane parallel to the loading surface 28. The vehicle contact unit 16 can even be moved along the loading surface 28, i.e., parallel to it, when the vehicle contact unit 16 rests on the loading surface 28.

[0156] The translational and / or rotational relative movement of the vehicle contact unit 16 to the loading area 28 ensures that the contacts 30 of the vehicle contact unit 16 and the contacts 30 of the ground contact unit 18 can come into contact, i.e. overlap.

Claims

Patent claims 1. Charging infrastructure (12) for establishing a conductive connection with a vehicle contact unit (16), wherein the charging infrastructure (12) comprises a ground contact unit (18) having a plate-shaped base body (26) and several contacts (30) arranged on a loading surface (28) of the base body (26) against which the vehicle contact unit (16) can be placed, wherein the several contacts (30) comprise at least one protective conductor contact (36), power contacts (32) and at least one control contact (40) for detecting contact, wherein the at least one protective conductor contact (36) is permanently wired, wherein the power contacts (32) are assigned to at least one potential level (34), wherein the at least one control contact (40) is designed separately from the power contacts (32) and separately from the at least one protective conductor contact (36).

2. Charging infrastructure (12) according to claim 1, characterized in that at least two power contacts (32) are assigned to the same potential level (34), in particular wherein several potential levels (34) are provided, wherein at least two power contacts (32) are assigned to each potential level (34).

3. Charging infrastructure (12) according to claim 1 or 2, characterized in that the charging infrastructure (12) comprises a monitoring circuit (20) which is configured to monitor the contacting of the at least one control contact (40), in particular wherein the monitoring circuit (20) is configured to determine a contact position of the vehicle contact unit.

4. Charging infrastructure (12) according to one of the preceding claims, characterized in that the at least one control contact (40) has a smaller area than the at least one protective conductor contact (36) and / or than one of the power contacts (32), in particular than each of the power contacts (32).

5. Charging infrastructure (12) according to one of the preceding claims, characterized in that the multiple contacts (30) comprise at least two control contacts (40) such that the charging infrastructure (12) is configured to detect a contacting orientation of the vehicle contact unit (16) on the charging surface (28) by means of the at least two control contacts (40), in particular wherein the multiple contacts (30) comprise two categories of control contacts (40) which differ in terms of the control signals used which are passed through the control contacts (40).

6. Charging infrastructure (12) according to one of the preceding claims, characterized in that the at least one protective conductor contact (36) is formed by a continuous surface which provides a protective conductor level (38) which is interrupted by the power contacts (32) and / or the at least one control contact (40).

7. Vehicle contact unit (16) for establishing a conductive connection with a ground contact unit (18), wherein the vehicle contact unit (16) has several contacts (30) that can come into contact with a loading surface (28) of the ground contact unit (18), wherein the vehicle contact unit (16) is movable translationally and / or rotationally in a plane parallel to the loading surface (28), wherein the several contacts (30) comprise at least one protective conductor contact (36), power contacts (32) and at least one control contact (40) for detecting contact, wherein the at least one protective conductor contact (36) is permanently wired, wherein the power contacts (32) are assigned to at least one potential level (34), wherein the at least one control contact (40) is designed separately from the power contacts (32) and separately from the at least one protective conductor contact (36).

8. Vehicle contact unit (16) according to claim 7, characterized in that the contacts (30) are designed such that the at least one control contact (40) loses contact with the ground contact unit (18) earlier than the power contacts (32) and / or the at least one protective conductor contact (36) during a relative movement of the vehicle contact unit (16) to the ground contact unit (18), and / or that the at least one protective conductor contact (36) loses contact with the ground contact unit (18) later than the power contacts (32) during a relative movement of the vehicle contact unit (16) to the ground contact unit (18).

9. System (10) for establishing a conductive connection, wherein the system (10) comprises a vehicle contact unit (16) with multiple contacts (30) comprising at least one protective conductor contact (36), power contacts (32) and at least one control contact (40) for detecting contact, wherein the system (10) has a ground contact unit (18) with a plate-shaped base body (26) and several contacts (30) arranged on a loading surface (28) of the base body (26) and comprising at least one protective conductor contact (36), power contacts (32) and at least one control contact (40) for detecting contact, wherein the at least one protective conductor contact (36) is permanently wired, wherein the respective power contacts (32) are assigned to at least one potential level (34), wherein the respective at least one control contact (40) is designed separately from the power contacts (32) and separately from the at least one protective conductor contact (36), wherein the vehicle contact unit (16) is movable translationally and / or rotationally in a plane parallel to the loading surface (28),wherein the system (10) comprises a monitoring circuit (20) and a signal generator (64), wherein the system (10) is configured to apply a control signal by means of the signal generator (64) to at least one control contact (40) of the ground contact unit (18) or the vehicle contact unit (16), and wherein the system (10) is configured to detect contacting the ground contact unit (18) by means of the monitoring circuit (20), which is configured to receive and evaluate the control signal generated by the signal generator (64), which, in the contacted state, passes through the at least one control contact (40) of the vehicle contact unit (16) and / or the at least one control contact (40) of the ground contact unit (18).

10. System (10) according to claim 9, characterized in that the contacts (30) of the ground contact unit (18) and the contacts (30) of the vehicle contact unit (16) are designed such that a connection via the protective conductor contact (36) of the ground contact unit (18) and the protective conductor contact (36) of the vehicle contact unit (16) remains in place when the connections via the power contacts (32) have already been broken off during a relative movement of the vehicle contact unit (16) to the ground contact unit (18), in particular due to a relative movement of the vehicle contact unit (16) to the ground contact unit (18).

11. System (10) according to claim 9 or 10, characterized in that the at least one control contact (40) of the ground contact unit (18) and / or the at least one control contact (40) of the vehicle contact unit (16) is designed such that a connection via the control contact (40) of the ground contact unit (18) and the control contact (40) of the vehicle contact unit (16) breaks down during a relative movement of the vehicle contact unit (16) to the ground contact unit (18) before the connections via the power contacts (32) break down.

12. Method for establishing a conductive connection between a ground contact unit (18) and a vehicle contact unit (16), wherein the vehicle contact unit (16) has several contacts (30) comprising at least one protective conductor contact (36), power contacts (32) and at least one control contact (40) for detecting contact, wherein the ground contact unit (18) has a plate-shaped base body (26) and several contacts (30) arranged on a loading surface (28) of the base body (26) and comprising at least one protective conductor contact (36), power contacts (32) and at least one control contact (40) for detecting contact, wherein the at least one protective conductor contact (36) is permanently wired, and wherein the respective power contacts (32) are assigned to at least one potential level (34).wherein the respective at least one control contact (40) is designed separately from the power contacts (32) and separately from the at least one protective conductor contact (36), wherein the vehicle contact unit (16) is movable translationally and / or rotationally in a plane parallel to the loading platform (28), wherein the method comprises the following steps: - Applying a control signal to at least one control contact (40) of the ground contact unit (18) or the vehicle contact unit (16), and Measure whether the control signal is transmitted via a continuous connection that includes at least the control contact (40) of the ground contact unit (18) and / or the control contact (40) of the vehicle contact unit (16).

13. Method according to claim 12, characterized in that a contacting area (A) of the vehicle contact unit (16) on the ground contact unit (18) is identified by rotating the vehicle contact unit (16) relative to the ground contact unit (18) and / or several control contacts (40) of the The ground contact unit (18) can be switched through individually and / or in groups.

14. Method according to claim 12 or 13, characterized in that an orientation of the vehicle contact unit (16) relative to the ground contact unit (18) is identified by applying different control signals to at least two control contacts (40) of the ground contact unit (18) or the vehicle contact unit (16).

15. Method according to one of claims 12 to 14, characterized in that a cleaning check is carried out by applying a low-level protection voltage to the at least one control contact (40) of the ground contact unit (18), wherein an insulation check is carried out between two contacts (30) of the ground contact unit (18).

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