Ground contact unit for a vehicle battery charging system and method for switching the contact area of the ground contact unit

Abstract

A ground contact unit for a vehicle battery charging system has: a substrate; at least one potential (24); a plurality of contact areas (20); a plurality of switching units (26); and a plurality of switching lines (44, 46) by means of which the switching units (26) can be actuated, wherein a plurality of switching units (26) are provided on each of the switching lines (44, 46). The switching lines (44, 46) are divided into at least two groups, and each switching unit (26) is provided at at least two switching lines (44, 46) in at least two different groups such that the switching state of the switching unit (26) is related to the signal state at the associated switching lines (44, 46). Each switching unit (26) is coupled to at least one contact area (20) such that the switching unit (26) can electrically connect and disconnect the corresponding at least one contact area (20) from at least one potential (24) associated with the contact area (20). Furthermore, a method for switching contact areas is shown.

Description

Field of the Invention

[0001] In the case of electrically driven vehicles such as plug-in hybrid vehicles and battery electric vehicles, the vehicle's battery must be charged regularly, preferably after each trip. For this purpose, the vehicle is connected to a current source, such as the local power grid, by means of a vehicle coupling system. Here, a plug connector, such as a type 2 plug connector, can be used, which must be manually inserted by a person into the corresponding socket of the vehicle. Background Art

[0002] Known, for example, is a vehicle coupling system for a vehicle battery charging system, which has a contact unit for current terminals arranged on the ground. The ground contact unit arranged on the ground is physically contacted by a movable vehicle contact unit, which can move downwards from the underside of the vehicle. In this way, an electrical connection between the vehicle and the local power grid can be achieved.

[0003] Here, it is necessary that the electrodes arranged on the vehicle contact unit physically contact the contact surfaces of the ground contact unit. For this purpose, the vehicle contact unit must not only be positioned above the ground contact unit when the vehicle is parked, but also the correct electrodes of the vehicle contact unit must be located on the corresponding contact surfaces of the ground contact unit and switched accordingly, since the electrodes or contact surfaces have different functions. It is important here that only the contact surfaces of the ground contact unit located in the area of the vehicle contact unit are energized, so that there are no exposed, energized contact surfaces. Summary of the Invention

[0004] Accordingly, it is an object of the present invention to provide a simple and low-cost ground contact unit for an automatic vehicle battery charging system and a method for switching the contact areas of the ground contact unit, by means of which a physical electrical connection between the vehicle contact unit and the ground contact unit can be achieved in an automatic manner and incorrect contact is excluded.

[0005] The object is achieved by a ground contact unit for a vehicle battery charging system, which is used for an automatic, conductive connection between the ground contact unit and the vehicle contact unit, the ground contact unit having: a plate-shaped base body; at least one potential; a plurality of contact areas arranged on the exposed loading surface of the base body and associated with at least one potential; a plurality of switching units; and a plurality of switching lines by means of which the switching units can be actuated, wherein a plurality of switching units are provided on each switching line.

[0006] The switching circuit is divided into at least two groups, each of which has a plurality of switching circuits, and each of the switching units is provided at at least two switching circuits in at least two different groups, in particular at one switching circuit in each group, such that the switching state of the switching unit is related to the signal state at the associated switching circuit.

[0007] Each of the switching units is coupled to at least one in the contact area such that the switching unit can electrically connect and disconnect the corresponding at least one contact area and at least one potential associated with the contact area.

[0008] The exposed loading area of the substrate is configured such that the vehicle contact unit can abut or lean against the loading surface.

[0009] Since the switching circuit is divided into several groups and the switching units are connected to the switching circuits of different groups, it is possible to dispense with: for each switching unit having at least one own output of its own electrical control switch or control unit (microcontroller), a ground contact unit with its own direct cable laying. More precisely, now only one electrical control switch is required for each switching circuit, whereby the number of required electrical control switches and cable laying can be significantly reduced without suffering a loss of function of the ground contact unit. In other words, with the present invention, it is not necessary for each switching unit to have at least one output of two lines and a microcontroller of the ground contact unit. Therefore, the ground contact unit can be manufactured simply and at low cost.

[0010] The switching unit can include an electromechanical switch - such as a relay -, an electronic switch - such as a field effect transistor (e.g., MOSFET) or TRIAC (triode for alternating current) - and / or other logic switches.

[0011] If the switching unit includes an electronic switch, such as a TRIAC or a field effect transistor, then the switching unit can also have a pre-circuit each, and the electronic switch is connected to the switching circuit via the pre-circuit.

[0012] The pre-circuit generates an output signal at the electronic switch, for example, based on the signal of the switching circuit, and the output signal switches the corresponding electronic switch. The pre-circuit is, for example, an AND gate or a NAND gate.

[0013] In order to use the contact area flexibly, at least one potential can be connected to the ground potential, neutral conductor, external conductor or current source, especially the phase, positive or negative pole of the local power grid, in particular where for the ground potential, the neutral conductor, external conductor or current source has its own potential for the phase, positive and / or negative pole respectively.

[0014] In the context of the present invention, for the sake of simplicity, the outdated term "phase" is used for the external conductor.

[0015] Furthermore, for the sake of simplicity, the potential connected to the external conductor or phase is referred to as the potential voltage, although the potential does not have a constant potential, but its potential changes periodically with the potential of the corresponding external conductor.

[0016] Preferably, the switching lines can be loaded with voltage and / or current separately from each other, whereby the switching unit can be switched in a targeted and effective manner.

[0017] For example, the ground contact unit has at least one PE potential, wherein the switching unit is configured such that the switching unit can electrically connect the associated contact area to the associated potential voltage or at least one PE potential. In this way, it is ensured that if the corresponding contact area or the entire ground contact unit is not used, there is no current-carrying and / or voltage-carrying contact area. In particular, the PE potential is at the ground potential.

[0018] Alternatively or additionally, the ground contact unit can have a PE contact area that is permanently connected to at least one PE potential.

[0019] Preferably, exactly one switching unit is provided for each contact area, especially for a contact area that is not a PE contact area, thereby achieving a particularly flexible and low-cost structure.

[0020] In order to simply change the potential of the contact area, if the switching line associated with the switching unit is switched appropriately, especially switched with the correct polarity in a common electrical circuit, the switching element of the switching unit can electrically connect the corresponding at least one contact area to the associated potential voltage.

[0021] Preferably, the switching line on which one of the switching units is provided is different from the switching line on which another switching unit of the switching units is provided in at least one switching line. In this way, the switching unit can be clearly controlled.

[0022] In other words, the control of each switching unit is carried out by means of a combination of at least two switching lines, wherein each switching unit can be manipulated by a specific combination of switching lines, or each combination of switching units is associated with only one switching unit.

[0023] For example, for each switching unit, only one switching line is provided for each group and is coupled to the switching line.

[0024] In a design of the present invention, a set of switching lines extends substantially in the same direction, especially parallelly, and / or the switching lines form a grid, and the switching lines of different sets intersect at the intersections of the grid, where switching units are respectively arranged at the intersections. Preferably, the switching units can only be switched on their switching lines at different potentials. In this way, a compact layout of the contact areas of the base plate can be achieved.

[0025] Preferably, the directions of different sets form an angle with each other, especially where the angle between different sets is 90° and / or of the same size, so that a feasible overall structure is achieved.

[0026] For example, the switching lines of different sets extend perpendicular to each other, such that the switching lines of one of the sets form several rows, while the switching lines of the other set form several columns. Here, in particular, each combination formed by a specific row and a specific column is associated with exactly one switching unit.

[0027] The switching lines of at least one of the sets can extend in a zigzag shape to enable a more complex geometry.

[0028] In an implementation variant, each of the switching units has two switching contacts, which are connected to the switching lines, so that the switching units can be simply integrated into the electrical circuit.

[0029] For example, one of the switching contacts is connected to the switching lines of a set via at least one diode, while the other switching contact of the switching contacts is connected to the switching lines of another set, thereby improving the operating safety.

[0030] In order to reliably switch the contact area, the switching unit can be configured such that if there is at least a predetermined voltage difference between the switching contacts, then the switching unit electrically connects the contact area associated with it to the potential associated with it.

[0031] In another design of the present invention, the ground contact unit has at least one control line, and the switching unit has a double-way switch as a switching element, especially a relay, where the double-way switch is configured such that the control line is only electrically connected to a specific potential, especially the PE potential, when the contact area is also connected to a specific potential. In this way, the number of contact areas connected to the PE potential can be determined.

[0032] The query of the number can be carried out via voltage measurement on all control lines or alternately on each control line by means of a multiplexer.

[0033] For example, the two-way switch is configured such that one of the switches in the two-way switch can electrically connect the control line to the contact area, and only when the control line is also electrically connected to the contact area, can the other switch of the two-way switch electrically connect the contact area to a specific potential, in particular the PE potential. Thus, it can be recognized that if the control line is also at the ground potential, then the contact area is at the ground potential.

[0034] Here, the two-way switch can be forced to guide such that the contact area is connected to the control line and the PE potential, or the contact area is only connected to the potential associated with it.

[0035] For example, the contact area on the loading surface and / or its contact surface is arranged in the form of a grid of a two-dimensional Bravais lattice. This grid is also called the main grid.

[0036] In a design of the present invention, the ground contact unit has a first potential, a second potential, and a third potential. The contact area associated with the first potential forms a first contact area, the contact area associated with the second potential forms a second contact area, and the contact area associated with the third potential forms a third contact area. The first contact area is arranged as a first sub-grid in the form of a two-dimensional Bravais lattice, the second contact area is arranged as a second sub-grid in the form of a two-dimensional Bravais lattice, and the third contact area is arranged as a third sub-grid in the form of a two-dimensional Bravais lattice. The first sub-grid, the second sub-grid, and the third sub-grid are nested with each other here, and in the direction of at least one basis vector in the basis vectors of the main grid formed by the contact area, the first contact area, the second contact area, and the third contact area appear alternately. In this way, a high-performance ground contact unit with contact areas that can be switched to different potentials can be realized. By being arranged in the grid, the potentials of the contact areas with different potentials relative to each other are always known and fixed, so that sub-regions of the loading surface have different contact areas with different potentials.

[0037] Furthermore, the object is achieved by a method for switching the contact area of the ground contact unit according to the present invention to a desired potential, the method having the following steps:

[0038] a) Applying a predetermined voltage with a predetermined polarity to the switch line, the switch unit associated with the contact area to be switched abuts against the switch line, whereby the switch unit is manipulated such that the contact area is electrically connected to at least one potential associated with it, and

[0039] b) Applying the desired potential to at least one potential associated with the contact area to be switched, in particular via a main disconnector or a disconnector provided in the substrate and / or upstream of the contact area.

[0040] In this way, the electrical position of the contact area can be placed at the desired potential very simply and effectively. The predetermined voltage here is the voltage required to manipulate the switching unit.

[0041] The main disconnect switch and / or the disconnect switch are, for example, charging protectors.

[0042] For example, a positive voltage, in particular +12V or +6V, is applied to the switching line of one of the groups, while a negative voltage, in particular -12V or -6V, is applied to the switching line in the other group, thereby generating a defined voltage drop at exactly one switching unit in particular.

[0043] To check the switching state of a plurality of switching units and / or the potential of a plurality of contact areas, a voltage can be determined on the control line, and the number of switched and / or unswitched contact areas can be inferred from the magnitude of the voltage.

[0044] In an embodiment variant, the current flowing through the energized switching line in the switching line is limited such that only a specific number of switching units can be switched via this switching line. In this way, inadvertent incorrect switching can be prevented.

[0045] Furthermore, the object can be achieved by a vehicle battery charging system for automatically conductively connecting a ground contact unit and a vehicle contact unit to the ground contact unit and to the main electrical terminals for a current source or the power grid,

[0046] wherein the ground contact unit has a plate-shaped base body, a plurality of potential levels and a plurality of contact areas, the ground contact unit is arranged on the exposed loading surface of the base body, and the vehicle contact unit can abut against the loading surface and is associated with at least one potential level,

[0047] wherein the vehicle battery charging system has: a main disconnect switch, for example a main charging protector; and a plurality of disconnect switches, for example charging protectors or relays, wherein the main disconnect switch is configured to disconnect a plurality of, in particular all, potential levels from the main terminal current,

[0048] Each of the plurality of disconnect switches is associated with one of the plurality of potential levels, and the disconnect switches are configured to disconnect the potential level associated therewith from the main terminal current. In this way, a dual current disconnection of the contact surface is possible - via the main disconnect switch or the main charging protector and the plurality of disconnect switches or charging protectors - and at the same time the potential level can be selectively set to a desired potential via the respective disconnect switch. This dual function of the plurality of disconnect switches enables component savings. In addition, the switching unit in the contact area does not have to be switched in the energized state.

[0049] In one embodiment variant, the plurality of disconnect switches are configured to selectively connect the potential level associated therewith to at least two, in particular at least three, ground terminals. Thereby, the potential of the respective potential level can be selectively selected.

[0050] For example, the vehicle battery charging system has a switch cabinet having a main terminal, a main disconnect switch (such as a main charging protector) and / or a plurality of disconnect switches (such as charging protectors). Thereby, the ground contact unit can be formed at low cost without a plurality of components.

[0051] The main disconnect switch and / or the plurality of disconnect switches can also be provided in the ground contact unit. For example, the main disconnect switch is located in the switch cabinet, while the plurality of disconnect switches are located in the ground contact unit. In this way, the vehicle charging system can be adapted to different situations providing different spaces.

[0052] Obviously, all features of the above-described ground contact unit according to the invention can also be provided in a vehicle battery charging system, and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Other features and advantages of the invention result from the following description and the appended drawings. Shown in the drawings are:

[0054] Figure 1 A vehicle coupling system is schematically shown having a vehicle contact unit and a ground contact unit according to the invention;

[0055] Figure 2 a shows a top view of a first embodiment of the ground contact unit according to the invention;

[0056] Figure 2 b schematically shows according to Figure 2 a a simplified cross-sectional view of a part of the ground contact unit;

[0057] Figure 3 Schematically shows the arrangement of different contact areas of the ground contact unit according to Figure 2 a;

[0058] Figure 4 Shows an equivalent circuit diagram of the electrical arrangement of four contact areas of a ground contact unit according to Figure 2 a;

[0059] Figure 5 Shows an equivalent circuit diagram of the electrical arrangement of four contact areas of a ground contact unit according to Figure 2 a;

[0060] Figure 6 Shows a simplified embodiment of a ground contact unit according to the present invention;

[0061] Figure 7 Shows a top view of a part of a ground contact unit according to Figure 2 a in contact with a shown vehicle contact unit;

[0062] Figure 8 Shows a top view of a part of a second embodiment of a ground contact unit according to the present invention in contact with a shown vehicle contact unit;

[0063] Figure 9 Shows a top view of a part of a third embodiment of a ground contact unit according to the present invention in contact with a shown vehicle contact unit;

[0064] Figure 10 Shows a part of an equivalent circuit diagram of a ground contact unit according to Figure 9 ;

[0065] Figure 11 Shows a schematic structure of the ground side part of a vehicle battery charging system according to the present invention;

[0066] Figure 12 Shows an equivalent circuit diagram of the electrical arrangement of two control lines of a ground contact unit according to Figure 2 a;

[0067] Figure 13 Shows an equivalent circuit diagram of the electrical arrangement of the contact areas of a ground contact unit for another embodiment according to the present invention. DETAILED DESCRIPTION

[0068] In Figure 1 is shown a vehicle 10, such as a battery-powered vehicle or a plug-in hybrid vehicle, parked on or above a ground contact unit 12 for charging a battery.

[0069] A vehicle connection device having a vehicle contact unit 14 is fixed to the underside of the vehicle 10, and the vehicle contact unit is capable of electrically connecting the vehicle 10 to the ground contact unit 12.

[0070] The ground contact unit 12 and the vehicle connection device 14 are part of an automatic vehicle coupling system 15, which in turn is part of a vehicle battery charging system.

[0071] In Figure 2 a top view shows the ground contact unit 12.

[0072] The ground contact unit 12 has a plate-shaped base body 16, on the upper side of which a loading surface 18 is provided.

[0073] The loading surface 18 is exposed on the upper side of the ground contact unit 12, that is, on the side facing the vehicle 10 and the vehicle contact unit 14.

[0074] In the loading surface 18, a plurality of different contact areas 20 are provided, each of which has at least one contact surface.

[0075] The contact areas 20 are each closed surfaces having a hexagonal, in particular regular hexagonal, contour. If necessary, the corners of the hexagon can have a radius.

[0076] The contact areas 20 and / or the contact surfaces can be in a plane, for example, the loading surface 18 is this plane.

[0077] The contact areas 20 are arranged in a main pattern. In the illustrated embodiment, the main pattern is a two-dimensional Bravais lattice, more precisely a hexagonal lattice. Thus, the main pattern is a main grid G H with two basis vectors h1, h2 of the same length, which form an angle of 120° with each other.

[0078] The main pattern or main grid G H extends over the entire loading surface 18.

[0079] In addition, the ground contact unit 12 has a plurality of ground terminals 22, three ground terminals in the illustrated embodiment, namely a first ground terminal 22.1, a second ground terminal 22.2 and a third ground terminal 22.3, which are connected to corresponding terminals of a local power grid (not shown) at the location of the ground contact unit 12 via a main terminal 23. Each of the ground terminals 22 provides a different potential.

[0080] As shown in Figure 2 b, at least one potential 24 is provided for each potential of the ground terminal 22 in the ground contact unit 12. Thus, in the illustrated embodiment, there are a first potential 24.1, a second potential 24.2 and a third potential 24.3.

[0081] However, for example, there are three potential levels 24, and other numbers of potential levels 24 are also feasible. In the illustrated embodiment, the potential levels 24 are substantially continuous or full-surface layers in the ground contact unit 12 made of a conductive material. The potential levels 24 extend at least over the entire area of the loading surface 18. Different potential levels 24 are insulated from each other.

[0082] For example, the potential levels 24 are conductive layers of a printed circuit board.

[0083] Obviously, the potential levels 24 do not have to be complete or flat layers. In addition, the potential levels 24 can also be constituted by laying corresponding cables.

[0084] For example, the first ground terminal 22.1 is electrically connected to a phase or an external conductor of the local power grid via the main terminal 23, the second ground terminal 22.2 is electrically connected to the neutral conductor of the local power grid via the main terminal 23, and the third ground terminal 22.3 is electrically connected to the protective conductor of the local power grid via the main terminal 23.

[0085] Correspondingly, the potential levels 24.1, 24.2, and 24.3 associated with the ground terminals 22.1, 22.2, and 22.3 can be placed at the potential of the external conductor, the neutral conductor, or the protective conductor (ground potential; PE). Therefore, the third potential level 24.3 is also referred to as the PE potential.

[0086] To electrically connect the ground terminal 22 to the corresponding potential level 24, a disconnection switch 27 ( Figure 11 ) is provided for each of the potential levels 24, such as a charging protector or a relay. In the case of the PE potential, the disconnection switch 27 can be omitted.

[0087] The disconnection switch 27 can be arranged in the base body 16 and connected upstream of the contact area 20, that is, arranged between the ground terminal 22 or the main terminal 23 and the contact area 20 or the switch unit 26.

[0088] It is also conceivable that the disconnection switch 27 is arranged in the switch cabinet 70 outside the ground contact unit 12 of the vehicle battery charging system.

[0089] The disconnection switch 27 can disconnect the potential level 24 associated therewith, for example, from the ground terminal 22 associated with the potential level 24, or connect it to the PE terminal of the ground terminal 22.

[0090] It is also feasible that the disconnection switch 27 connects the potential level 24 associated therewith to one of the three (or more) of the ground terminals 22 so as to be able to change the potential of the potential level 24. This is shown by the dotted line in Figure 11

[0091] ​In an alternative embodiment, the disconnect switch 27 is not provided because the contact area 20 can also be disconnected from the ground terminal 22 associated with the respective potential 24 by means of the switch unit 26. For this purpose, the contact area 20 is connected to the PE terminal of the ground terminal 22.

[0092] Furthermore, a main disconnect switch 29 is provided, which is configured as a main charging protector in the illustrated embodiment. In the illustrated embodiment, the main disconnect switch 29 is provided in the switch cabinet 70.

[0093] Obviously, other switches, such as relays, can be used as charging protectors, either as the main disconnect switch 29 or as the disconnect switch 27.

[0094] The main disconnect switch 29 is provided between the main terminal 23 and the disconnect switch 27.

[0095] In the case of DC charging, the first and second ground terminals 22.1, 22.2 are connected to the positive and negative poles of the DC power supply for charging.

[0096] Each of the contact areas 20 is connected or connectable to one of the potentials 24. The electrical connection can be permanent, but can also be switchable. In the case of the switchable contact area 20, the electrical connection can be switched back and forth between two potentials 24, or the electrical connection to the potential can be interrupted.

[0097] When the contact area 20 is contacted by the vehicle contact unit 14, each contact area 20 is associated with a potential 24, and the contact area 20 is electrically connected to this potential.

[0098] For example, two-thirds of the contact areas 20 are switchable, while the other one-third of the contact areas 20 are non-switchable.

[0099] In the first embodiment, three different types of contact areas 20 are provided, wherein the first contact area 20.1 is associated with the first potential 24.1, the second contact area 20.2 is associated with the second potential 24.2, and the third contact area 20.3 is associated with the third potential 24.3.

[0100] The first contact area 20.1 and the second contact area 20.2 are switchable. The first contact area and the second contact area can be switchably connected to the first potential 24.1 or the second potential 24.2 by means of the arrangement shown in Figure 4 can be switchably connected to the first potential 24.1 or the second potential 24.2.

[0101] In the illustrated embodiment, the third contact region 20.2 is permanently electrically connected to the third potential 24.3, i.e., the PE potential. Thus, the third contact region 20.3 is the PE contact region 25.

[0102] In Figure 3 is locally shown the main grid G formed by the contact regions 20 or 20.1, 20.2, 20.3 H . For simplicity, the contact region 20 is shown as circular.

[0103] The first contact region 20.1, the second contact region 20.2, and the third contact region 20.3 or the PE contact region 25 are each provided in their own sub-pattern, here in the form of a two-dimensional Bravais grid, i.e., a sub-grid.

[0104] The first contact region 20.1 is provided in a first sub-grid G i,1 with basis vectors u i,2 and u U1 . The first sub-grid G U1 is also a hexagonal grid, such that the two basis vectors u i,1 and u i,2 have the same magnitude and form an angle of 120° with each other.

[0105] Similarly, the second contact region 20.2 is provided in a second sub-grid G 2,1 with basis vectors U 2,2 and U U2 , the basis vectors likewise having the same magnitude and forming an angle of 120°.

[0106] The third contact region 20.3 or the PE contact region 25 is also located on a hexagonal third sub-grid G 3,1 with basis vectors U 3,2 and U U3 of the same length, the basis vectors forming an angle of 120°.

[0107] The three sub-grids G U1 and G U2 and G U3 are arranged nested with each other, such that the three different contact regions 20.1, 20.2, 20.3 or 25 appear continuously alternating along one of the basis vectors h1, h2 of the main grid G H .

[0108] In other words, the contact region 20.1, 20.2, 20.3 or 25 that is closest adjacent to any considered contact region 20.1, 20.2, 20.3 or 25 always has a different type than the considered contact region 20.1, 20.2, 20.3 or 25 itself.

[0109] The contact areas 20.1, 20.2, 20.3 or 25 or the contact surfaces are thus arranged rotationally symmetrically about a rotational axis perpendicular to the loading surface 18. The entire ground contact unit 12 can also be configured to be rotationally symmetric, meaning that at least the visible and the components required for connection to the vehicle contact unit 14 are arranged in a rotationally symmetric manner.

[0110] In Figure 4 a partial view of the equivalent circuit diagram of the ground contact unit 12 is shown, which shows the electrical arrangement for the switchable contact area 20.

[0111] By means of the electrical arrangement, the switchable contact area 20 can be connected to different potentials 24.

[0112] The contact area 20 is located at the Figure 4 center, and the potential 24 associated with the contact area 20 is shown as the uppermost line in Figure 4 .

[0113] Furthermore, for each switchable contact area 20, a switch unit 26, a control line 28, and a ground 30 are provided.

[0114] The ground 30 can be configured to be permanently connected to the potential 24 at ground potential, i.e., permanently connected to the PE potential.

[0115] The switch unit 26 has an actuating element 32 and a switching element 34 and is configured as an electromechanical switch in the illustrated embodiment, specifically as a relay, where the relay switch serves as the switching element 34 and the relay coil serves as the actuating element 32.

[0116] In the illustrated embodiment, the switching element 34 is a two-way switch 36 having a first switch 38 and a second switch 40.

[0117] The first switch 38 and the second switch 40 each form a switching contact, which is always connected to the contact area 20.

[0118] In Figure 4 the upper part shown, the first switch 38 can electrically connect the contact area 20 to the control line 28 or the potential 24.

[0119] The second switch 40 shown below can connect the contact area 20 to the ground 30 or the potential 24.

[0120] The two-way switch 36 can be actuated by the actuating element 32, where the first switch 38 and the second switch 40 are actuated simultaneously.

[0121] The first switch 38 and the second switch 40, i.e., the two-way switch 36, are configured such that the contact area 20 is connected to the ground 30 and the control line 28 via the two-way switch, or the contact area 20 is only electrically connected to the potential 24.

[0122] In other words, the switches 38 and 40 or the two-way switch 36 are forced-guided.

[0123] By means of the switch unit 26, the contact area 20 can thus be electrically connected to the associated potential 24 or disconnected from the potential 24, i.e., interrupted.

[0124] For electrically actuating or switching the switch unit 26, an electrical circuit 42 is provided, which has a first switch line 44 extending vertically (i.e., from top to bottom) in Figure 4 and a second switch line 46 extending horizontally (i.e., from left to right) in Figure 4 The first switch line 44 and the second switch line 46 can be separately energized or voltage-supplied via respective electrical control switches 52. The electrical control switches 52 are actuated, for example, by the control unit 54 of the ground contact unit 12.

[0125] The first switch line 44 and the second switch line 46 are connected to the switch unit 26, more precisely, to the actuating element 32.

[0126] For this purpose, the switch unit 26 or the actuating element 32 has two switch contacts 48. One of the two switch contacts 48 is electrically connected to the two switch lines 44, 46 via diodes 50, 51, respectively. The cathodes of the diodes 50, 51 face the actuating element 32 here, for example.

[0127] The diode 50 between the switch contact 48 and the switch line 44 has a switching function, while the diode 51 between the switch contact 48 and the switch line 46 is a protection diode, which protects the actuating element 32 from overvoltage when switched off.

[0128] The diode 50 between the switch contact 48 and the switch line 44 has a switching function, while the diode 51 between the switch contact 48 and the switch line 46 is a protection diode, which protects the actuating element 32 from overvoltage when switched off.

[0129] The other switch contact 48 is only electrically connected to one of the second switch lines 46 in the illustrated embodiment.

[0130] In the non-actuated state of the switch unit 26, i.e., when no voltage is applied between the switch contacts 48, the two-way switch 36 is in the position shown in Figure 4 i.e., the contact area 20 is electrically connected to the ground 30 and the control line 28.

[0131] In order to be able to switch the switch unit 26 and thus electrically connect the contact area 20 to the associated potential 24, a voltage must be generated via the switch contact 48, for example a voltage of 24 V or 12 V.

[0132] For this purpose, a positive voltage, for example a voltage of +12 V or +6 V, is applied to the first switch line 44, and a negative voltage, for example a voltage of -12 V or -6 V, is applied to the second switch line 46.

[0133] Since the diode 50 of the first switch line 44 now applies a voltage in the switching direction, a voltage of 24 V or 12 V is applied between the switch contacts 48 and thus to the actuating element 32, whereby the switching element 34, i.e. the two-way switch 36, is switched.

[0134] If only one of the switch lines 44, 46 is loaded with a voltage or is loaded with a voltage of the opposite polarity, no potential difference or voltage is generated by the diode 50 at the switch contacts 48 and the actuating element 32, so that the two-way switch 36 returns to its initial position.

[0135] Thus, the switching state of the switch unit 26 is related to the signal states on the switch lines 44, 46, i.e. whether a voltage is applied to the switch lines 44, 46 and with what polarity.

[0136] The contact area 20 can thus be electrically connected to the potential 24 associated with it and is thus activated.

[0137] In Figure 4 The arrangement shown is used for all switchable contact areas 20, i.e. for example for the first contact area 20.1 and the second contact area 20.2.

[0138] In Figure 5 An equivalent circuit diagram of six adjacent contact areas 20 is shown.

[0139] The contact areas 20 shown are Figure 3 exemplarily enclosed by a dashed line in

[0140] It can be clearly seen that the first and second contact areas 20.1, 20.2 are switchable contact areas 20.

[0141] Obviously, instead of Figure 3 the usual potential 24, only two potentials 24 are shown, more precisely the first potential 24.1 and the second potential 24.2.

[0142] The third potential 24.3 or the PE potential is not shown continuously, but the electrical connection thereto is represented as a ground symbol.

[0143] Each switchable contact area 20.1, 20.2 has a switch unit 26 associated therewith.

[0144] The first contact area 20.1 can be electrically connected to the first potential 24.1 via the switch unit 26 associated therewith, while the second contact area 20.2 can be electrically connected to the second potential 24.2 via the switch unit 26 associated therewith.

[0145] In Figure 5 it can be clearly seen that the switchable contact areas 20.1 and 20.2 are arranged in rows and columns with respect to the cable laying of their electrical circuit 42.

[0146] In Figure 5 for example, columns (n) and (n + 1) and rows (m) and (m + 1) are partially shown. In Figure 5 the contact area 20.1 shown in the upper right corner, for example, is present in column (n + 1) and row (m).

[0147] Each row and column has exactly one switch line 44, 46. In other words, each column or row is defined by the corresponding switch line 44, 46.

[0148] For example, each column is formed by the vertical first switch line 44, while each row is formed by the horizontally extending second switch line 46.

[0149] Therefore, the first switch line 44 belongs to the first group of switch lines representing columns, while the second switch line 46 belongs to the second group of switch lines representing rows.

[0150] In Figure 5 the (n)th and (n + 1)th first switch lines 46 and the (m)th and (m + 1)th second switch lines 46 are shown.

[0151] The (n)th first switch line 44 is connected to the switch unit 26, more precisely, to the actuating element 32, which is associated with and switches the contact area 20 of the (n)th column. The same applies to the (n + 1)th first switch line 44.

[0152] In a similar manner, the (m)th second switch line 46 is electrically connected to the switch unit 26, more precisely, to the actuating element 32 with respect to the contact area 20 of the (m)th column. The same applies to the (m + 1)th second switch line 46.

[0153] For illustration purposes, in Figure 6The ground contact unit 12 in another simplified embodiment is shown, where the contact area 20 or the contact surface is square and arranged in a square Bravais lattice.

[0154] The first switching line 44 and the second switching line 46 are shown by dashed lines or dotted lines. In this embodiment, the physical geometric arrangement of the switchable contact area 20 also corresponds to the electrical arrangement of the switchable contact area 20, making it more obvious to divide the contact area into rows and columns.

[0155] In this simplified embodiment, the first switching lines 44 are arranged parallel to each other, however perpendicular to the second switching lines 46, and the second switching lines also extend parallel to each other.

[0156] The switching lines 44, 46 thus form a grid, where each intersection is associated with a switch unit 26 or a switchable contact area 20.

[0157] Therefore, each switchable contact area 20 or its switch unit 26 is associated with exactly one combination of the first switching line 44 and the second switching line 46, and the switch unit 26 is switched by means of this combination.

[0158] Another switch unit 26 is different from any arbitrary switch unit 26 in that at least another first or second switching line 44, 46 is electrically connected thereto.

[0159] In particular, for each switch unit 26, there is provided only one switching line 44 or 46 in each group.

[0160] For example, in the first embodiment according to Figure 5 now, to connect the contact area 20.1 in column (n + 1) and row (m) to the potential 24.1, as already described with respect to Figure 4 a positive voltage is applied to the (n + 1) first switching lines 44, while a negative voltage is applied to the nth second switching line 46. The remaining first and second switching lines 44, 46 remain without current or voltage.

[0161] If the switchable contact area 20.2 in the (n + 1)th column and the (m + 1)th row should additionally be electrically connected to its associated potential 24.2, then a negative voltage is additionally applied to the (m + 1)th second switching line 46.

[0162] Therefore, a positive voltage is applied to one of the switch lines 44 of the first group of switch lines, while a negative voltage is applied to the two second switch lines 46 of the second group. Accordingly, the switch unit 26 associated with the contact areas 20 of column (n + 1) and rows (m) and (m + 1) is actuated, and the contact areas 20.1 and 20.2 are electrically connected to the associated potential differences 24.1 and 24.2.

[0163] At the same time, the current via the first switch line 44 of the (n + 1)-th column is restricted in order to prevent more than two switch units 26 from being actuated.

[0164] For this purpose, the current is restricted to a value sufficient to actuate approximately two switch units 26. Although in this case one or two switch units 26 may be switched too much at the same time, the current restriction can prevent significantly more switch units, such as 10 or 30 switch units 26, from being switched too much.

[0165] In the illustrated embodiment, a control line 28 is provided for each row, which branches if necessary in order to enable contact via the double-throw switch 36.

[0166] On each control line 28, a voltage source 62 is provided for each row.

[0167] In order to check whether all switchable contact areas 20 of the respective row are at ground potential, i.e., not activated, the voltage between the control line 28 and the ground potential or the PE potential is measured.

[0168] The measured voltage depends on how many parts of the control line 28 are connected to the ground 30, such that it is possible to check whether all switch units 26 are in the non-actuated state.

[0169] By way of example, Figure 12 an equivalent circuit diagram is shown therefor, in which the control line 28 for two contact areas 20 of one row is shown. A variable voltage divider with multiple arms is implemented by the switch units 26, which divides the voltage generated by the voltage source 62. Each switch unit 26 represents an arm.

[0170] The voltmeter 63 measures the voltage with respect to the ground potential via the arm of the voltage divider. The more switch units 26 connect the control line 28 to the respective ground 30, the lower the voltage measured by the voltmeter 63. Based on the measured value of the voltage, the number of non-actuated switch units 26 can be determined - and thus also the number of actuated switch units 26.

[0171] In this way, it is possible to identify the switch unit 26 that remains in the actuated state. This can be carried out, for example, by actuating the switch unit 26 during the application of a high potential to the respective potential 24. Then, during the switching process, an electric arc is generated, which welds the switching element 34 at the respective mating part. In particular, the forced-guided switching element 34 can thus be monitored with a high degree of safety.

[0172] It is also conceivable to use a multiplexer 72 in order to be able to measure the voltage between one of the control lines 28 and the ground potential alternately over time. In Figure 12 the multiplexer is shown in dashed lines.

[0173] In Figure 7 according to Figure 2 and Figure 4 a part of the loading surface 18 of the ground contact unit 12 in the first embodiment form is shown enlarged, in which the first switching line 44 and the second switching line 46 are also drawn nearby.

[0174] Furthermore, the contact area of the vehicle contact unit 14 is represented by a circle, which encloses the contact area 20 contacted by the vehicle contact unit 14.

[0175] Six switchable contact areas 20 are provided around the central PE contact area 20. The contact areas are also referred to as the first ring.

[0176] It is conceivable to provide six potential differences 24 for these six switchable contact areas 20, where each of these six contact areas 20 is associated with one potential difference 24.

[0177] It is also conceivable to provide two potential differences 24 for these six switchable contact areas 20. The potential differences can be loaded with a positive potential or a negative potential for charging with direct current. In the case of alternating current, the potential differences can represent the neutral conductor and the phase.

[0178] It is also conceivable to provide four potential differences 24 for these six switchable contact areas 20, i.e., three potential differences for the phase and one potential difference for the neutral conductor during alternating current charging.

[0179] It is also conceivable to provide six potential differences 24 for these six switchable contact areas 20, i.e., three potential differences for the phase and three potential differences for the neutral conductor during alternating current charging.

[0180] The PE potential 25 represents the seventh potential difference here.

[0181] In this case, seven sub-grids are generated because the sub-grid G U1and G U2 They are then divided into three sub-grids respectively. The sub-grids have basis vectors that form an angle of, for example, 120°. A pair of such basis vectors u’1 and u’2 are shown by dashed lines in Figure 3 .

[0182] It is conceivable that three potential differences 24 are provided for the six switchable contact areas 20, and these three potential differences represent three phases for charging with alternating current.

[0183] As also in the simplified embodiment according to Figure 6 in the first embodiment, there is a first set of first switching lines 44 extending vertically in Figure 7 and a second set of second switching lines 46 extending horizontally in Figure 7 .

[0184] Due to the hexagonal shape of the contact area 20 or the contact surface, these columns do not extend in a straight line but in a zigzag. However, despite this, the direction of the columns is still basically vertical and forms an angle of, for example, 90° with the rows.

[0185] Therefore, the first switching lines 44 of the first set connect the contact areas 20 or their switching units 26 arranged slightly staggered from each other, such that it can be said that the first switching lines 44 also extend in a zigzag.

[0186] In Figure 7 it is also clearly seen that the columns extend such that there are no PE contact areas 25 in the columns.

[0187] In Figure 7 in the example shown, the PE contact area 25 and the contact areas 20 of columns (n) and (n + 1) and rows (m), (m + 1) and (m + 1) are located in the part of the loading surface 18 contacted by the vehicle contact unit.

[0188] Once the switchable contact area 20 and the PE contact area 25 are electrically contacted by the corresponding electrodes (not shown) of the vehicle contact unit 14, the corresponding switchable contact area 20 is activated.

[0189] For this purpose, as described with respect to Figure 5 the first switching lines 44 of columns (n) and (n + 1) and the second switching lines 46 of rows (m), (m + 1) and (m + 2) are loaded with a predetermined positive or negative voltage to switch the switching units 26 such that the six switchable contact areas 20 are connected to the associated potential differences 24.1 and 24.2.

[0190] Now, the desired contact area 20 is connected to the associated potential 24.1 or 24.2, and the potentials 24.1 and 24.2 can now in turn be electrically connected to the corresponding ground terminals 22 so that the desired potential can be applied to the potentials 24.1, 24.2. To this end, the disconnect switches 27 for the potentials 24.1 and 24.2 are closed.

[0191] It is also conceivable that the disconnect switch 27 for switching the contact area 20 remains closed (or there is no disconnect switch 27), and for this purpose the main disconnect switch 29, here the main charging protector, is opened so that the contact area 20 or the potential 24 is DC-disconnected from the main terminal 23 for switching. In this case, the main disconnect switch 29 is now closed.

[0192] Then, the respective desired potentials are applied to the potential 24 and thus to the contact areas 20 of columns (n) and (n + 1) and rows (m), (m + 1) and (m + 2). Now, the vehicle 10 can be charged via the vehicle contact unit 14.

[0193] After the charging process is completed, the potentials 24.1 and 24.2 are disconnected from the associated ground terminals 22.

[0194] Subsequently, the respective contact areas 20 are disabled by removing the voltage on the first and second switch lines 44, 46.

[0195] The respective switch units 26 are switched to their unoperated state, thereby interrupting the electrical connection between the contact area 20 and the corresponding potential 24. At the same time, the respective contact areas 20 and the control lines 28 are electrically connected to ground 30 via protective resistors.

[0196] Then, it can be checked via the control line 28 whether the contact area 20 has been completely disconnected from its associated potential 24.1 or 24.2.

[0197] In this way, a functional ground contact unit 12 with a large number of mechanical switch units 26 can be realized, and thus a contact area 20 with a smaller number of electrically controlled switches 52 can be realized, and it can be realized with line savings.

[0198] In the embodiment under discussion, for example, for the arrangement of the contact areas 20 with x columns and y rows, i.e., a certain amount of x - y mechanical switch units 26 only require x + y electrically controlled switches 52.

[0199] This results in a significant simplification of the ground contact unit 12.

[0200] Other embodiments of the ground contact unit 12 according to the invention are described below, which embodiments essentially correspond to the first embodiment. Therefore, only the differences are studied, and identical and functionally identical components are provided with the same reference signs.

[0201] In Figure 8 a ground contact unit 12 is shown which is to be connected to a vehicle contact unit 14, which vehicle contact unit is larger than the vehicle contact unit 14 according to Figure 7 . More precisely, not only are six switchable contact areas 20 used around the central PE contact area 25 (first ring), but also switchable contact areas 20 are used in the next ring around the central PE contact area 25.

[0202] Then, the control of the contact areas via only two groups of switching lines is no longer possible, since in this case switchable contact areas 20 that are not located below the vehicle contact unit 14 are activated. This represents a safety risk and should be avoided. For the sake of illustration, the switchable contact areas 20 are additionally provided with the reference sign 64.

[0203] In order to be able to achieve a more targeted control of the switchable contact areas 20, a third group of switching lines, namely a third switching line 66, is used.

[0204] In addition to the already existing rows and the already existing columns, the third switching line 66 also defines another type of column.

[0205] The rows or the two types of columns extend respectively perpendicular to the sides of the hexagonal contact area 20, such that an angle of 60° is respectively formed between a row and a column or between two columns. The rows and the two columns are shown by lines in Figure 8 .

[0206] The switching units 26 of the contact areas 20 are thus respectively connected to three switching lines 44, 46, 66, and the respective switching elements are only actuated when the switching lines 44, 46, 66 provide voltage in a specific manner. For this purpose, for example, a suitable logic circuit (AND, NAND) and / or transistor circuit is formed.

[0207] Also in this embodiment, it is possible to provide a control line 28 for each row, by means of which it is possible to check whether the respective contact area 20 is disabled, i.e., at ground potential.

[0208] In Figure 9 and Figure 10 a third embodiment of the ground contact unit 12 is shown, which embodiment, like the embodiment according to Figure 8 , should also be suitable for a larger vehicle contact unit 14.

[0209] In this third embodiment, there are four sets of switching lines, namely a first switching line 44, a second switching line 46, a third switching line 66, and a fourth switching line 68.

[0210] As in the previous embodiments, the second switching line 46 forms the rows of the arrangement. However, in the third embodiment, there is only one type of column, which is defined by the remaining three sets of switching lines, namely the first switching line 44, the third switching line 66, and the fourth switching line 68. Therefore, the columns correspond to the columns of the first embodiment.

[0211] However, different from the first embodiment, not every switchable contact area 20 or its associated switch unit 26 is electrically connected to each of the first switching line 44, the third switching line 66, and the fourth switching line 68, but only to one of them.

[0212] For example, the first contact area 20 of a column is electrically connected to the first switching line 44, the second contact area of the column is electrically connected to the third switching line 66, the third contact area 20 of the column is electrically connected to the fourth switching line 68, and then the fourth contact area 20 of the column is electrically connected to the first switching line 44 again, and so on.

[0213] In other words, the first column is divided by the three sets of switching lines 44, 66, 68. Therefore, each column has the three sets of switching lines 44, 66, 68.

[0214] This can be seen particularly clearly in Figure 10 which shows the equivalent circuit diagram again.

[0215] In order to be able to activate, for example, the switchable contact area 20 marked with a solid dot in Figure 9 the second switching lines 46 of rows (m), (m + 1), (m + 2), (m + 3), and (m + 4) are loaded with a negative voltage, where the contact area is contacted by the vehicle contact unit 14.

[0216] In column (n), only one of the switching lines 44, 46, 66, here the first switching line 44, is loaded with a positive voltage. In columns (n + 1) and (n + 2), all three switching lines 44, 46, 66 are loaded with a positive voltage, and in column (n + 3), only one of the switching lines 44, 46, 66, here again the first switching line 44, is loaded with a positive voltage.

[0217] It is also achieved in this way that only those contact areas 20 contacted by the vehicle contact unit 14 are activated and thus electrically connected to the associated potential 24.

[0218] InFigure 13 Another embodiment of the ground contact unit 12 is shown.

[0219] In this embodiment, the switching unit 26 has an electronic switch 56 and a pre-circuit 58, where the electronic switch 56 serves as the switching element 34 and the pre-circuit 58 serves as the actuating element 32.

[0220] The electronic switch 56 is, for example, a MOSFET or a TRIAC.

[0221] The pre-circuit 58 is a logic circuit, such as an AND gate or a NAND gate, which has a switching contact 48 as an input. Thus, the pre-circuit 58 is electrically connected to the switching lines 44, 46 and thus, if necessary, also to the switching lines 66, 68.

[0222] The pre-circuit 58 is also electrically connected to the electronic switch 56 in order to control the electronic switch.

[0223] For this purpose, the pre-circuit 58 outputs a voltage to the electronic switch 56, where when the voltage output by the pre-circuit 58 exceeds a threshold value, the electronic switch 56 connects the contact area 20 to the associated potential 24.

[0224] The voltage output by the pre-circuit 58 is here related to the signals of the switching lines 44, 46 and, for example, only exceeds the threshold value when signals are applied to both switching lines 44, 46 simultaneously.

[0225] Thus, the mode of operation of the switching unit 26 composed of the electronic switch 56 and the pre-circuit 58 is the same as that of the switching unit 26 in the previous embodiment.

[0226] In this embodiment, it is also possible to check via the control line 28 whether the contact area 20 is connected to the associated potential 24. For example, whether this is done via voltage measurement or in some other way. It is also possible to use a multiplexer.

[0227] It is also conceivable that the electronic switch 56 switches the contact area 20 between the associated potential 24 and the PE potential 25.

[0228] However, it is also possible to dispense with the control line 28 because the electronic switch 56 does not have any movable parts.

[0229] Furthermore, in this embodiment, the diode 51 can be dispensed with.

[0230] Obviously, the features of the described embodiments can be combined with one another arbitrarily.

[0231] In other words, the embodiments of the invention can be described as follows:

[0232] In particular, row and column manipulation is used to release contact portions (hereinafter: contact areas) that are usually exposed on the upper side of the substrate. The reason for this is that this method saves circuitry and at the same time increases safety.

[0233] The control of the contact areas on the substrate is described below.

[0234] Figure 4 A circuit for relay control and a sensing line for a single contact area 20 are shown. By switching the disconnect switch 27 or the main disconnect switch 29, L1, L2, L3 or N is applied to the corresponding line. In order to also bring the phase or N conductor into actual contact with the contact portion, the relay must be switched. The control lines (also called switch lines) of the corresponding rows and columns are used to switch the relay.

[0235] Relays of 24V or 12V are preferably used. The 24V or 12V is achieved by applying +12V or +6V to the columns and -12V or -6V to the rows. Other relays can also be used. What is decisive is that the required switching voltage is obtained by switching the rows and columns, and thus safety is increased because two elements must be switched and thus an "AND" link is formed.

[0236] In order to detect whether the relay is actually switched, a sensing line (also called control line 28) is used. For this purpose, a test voltage is applied to the sensing line and the measured value changes according to the number of relays switched in each row. In this way, the number of relays switched in each row can be determined. If the relay "gets stuck" in this way (for example, due to the switching process at high voltage and subsequent welding due to arcing), then this can be detected with the help of the sensing line, and each row has its own sensing line.

[0237] Figure 5 A circuit diagram for 4 switchable contact portions and a non-switchable PE contact portion between them is shown.

[0238] Instead of a relay, any arbitrary switching unit, in particular a Triac, can also be used.

[0239] As a further safety function, the maximum number of switchable relays in each row and column is limited by the current limit in each row and column. This ensures that only the required number can be switched in each row and column.

[0240] Figure 7Shows the rows and columns required to switch the six currently required contact parts (to form a grid). The rows and columns are formed by corresponding switching lines. The black circles contain six contact parts, and the contact parts can be switched by three blue rows and two red columns without switching another contact part on the pad.

[0241] Control contact surface area

[0242] To switch the relay, an "AND condition" is required. If a larger connector (i.e., the interface of the vehicle contact unit) is to be used (as shown by the black circles in Figure 8 ), then this can be achieved in multiple ways. One possibility is to also add a second "AND condition". As shown in Figure 8 , this can be achieved by adding a second "AND condition" through another control line and only switching those contact parts / relays where the three control lines intersect. Figure 4 The circuit in

[0243] For Figure 4 One possibility to switch on a larger connector with the circuit in Figure 9 is to supplement each column with two control lines, thereby generating three control line groups per column, and connecting the column lines alternately to the relays in the corresponding column (see Figure 10 ). The wiring for this system is shown in

[0244] In a plate-shaped substrate, a plurality of potential differences, also called layers, are provided below the contact area. The potential differences are particularly configured as layers in a printed circuit board.

[0245] In the substrate of the switchgear or outside the substrate, a so-called charging protector can be provided, and then the high current is switched on by means of the charging protector. This means that usually, before switching on, the corresponding switch unit is pre-set to a so-called switching state through the charging protection, and then the high charging current is switched on via the charging protector.

[0246] There are usually seven potential differences, by means of which charging can be carried out via three-phase current, alternating current or direct current. As can be seen in Figure 7 , as the smallest unit on the contact area, there is a PE contact part and six contact areas arranged in a hexagon around it, that is, a total of seven contact areas including the PE contact area. Each of these contact areas has its own potential difference. In accordance with Figure 9In an implementation form, the rows and columns formed by the control circuit can also be interchanged. Shown are three switching circuits per column. Since generally one transistor is provided for each switching circuit, it is possible to reduce the electronic components by interchanging the rows and columns. It would make sense to interchange the rows and columns in accordance with the pad size (geometry) and thus the number of rows and columns in order to save components.

Claims

1. A ground contact unit for a vehicle battery charging system, the ground contact unit being for automatically conducting a connection between the ground contact unit (12) and a vehicle contact unit (14), the ground contact unit having: a plate-shaped base body (16); at least one potential (24); a plurality of contact areas (20) provided on the exposed loading surface (18) of the base body (16) and associated with at least one potential (24); a plurality of switching units (26); and a plurality of switching lines (44, 46, 66, 68), the vehicle contact unit (14) being able to abut against the loading surface, and the switching units (26) being able to be actuated by means of the switching lines, wherein a plurality of switching units (26) are provided on each of the switching lines (44, 46, 66, 68). Wherein the switching lines (44, 46, 66, 68) are divided into at least two groups, each of the two groups having a plurality of switching lines (44, 46, 66, 68), and each switching unit (26) is provided at at least two switching lines (44, 46, 66, 68) in at least two different groups, such that the switching state of the switching unit (26) depends on the signal state at the switching lines (44, 46, 66, 68) associated therewith. Wherein each switching unit (26) is coupled to at least one of the contact areas (20), such that the switching unit (26) can electrically connect and disconnect the corresponding at least one contact area (20) from at least one potential (24) associated with the contact area (20).

2. The ground contact unit according to claim 1, wherein, At least one of the potentials (24) can be connected to the ground potential, can be connected to the neutral conductor of a current source, the outer conductor of a current source or a phase of a current source, or can be connected to the positive or negative pole of a current source.

3. The ground contact unit according to claim 1 or 2, characterized in that, The switching lines (44, 46, 66, 68) can be loaded with voltage and / or current separately from one another.

4. The ground contact unit according to claim 1 or 2, characterized in that, The ground contact unit (12) has at least one PE potential, wherein the switching unit (26) is configured such that the switching unit can electrically connect the contact area (20) associated therewith to the potential (24.1, 24.2) associated therewith or to at least one PE potential.

5. The ground contact unit according to claim 1 or 2, characterized in that Just one of the switching units (26) is provided for each contact area (20).

6. The ground contact unit according to claim 1 or 2, characterized in that, If the switching lines (44, 46, 66, 68) associated with the switching unit (26) are switched appropriately, then the switching element (34) of the switching unit (26) can electrically connect the corresponding at least one contact area (20) to the potential (24) associated therewith.

7. The ground contact unit according to claim 1 or 2, characterized in that, The switching line (44, 46, 66, 68) on which one of the switching units (26) is provided is different from the switching line (44, 46, 66, 68) on which another of the switching units (26) is provided in terms of at least one switching line (44, 46, 66, 68).

8. The ground contact unit according to claim 1 or 2, characterized in that, A set of switching lines (44, 46, 66, 68) extends substantially in the same direction, and / or the switching lines (44, 46, 66, 68) form a grid, and different sets of switching lines (44, 46, 66, 68) intersect at the intersections of the grid, where switching units (26) are respectively provided at the intersections.

9. The ground contact unit according to claim 8, characterized in that, The directions of different sets form angles with each other.

10. The ground contact unit according to claim 1 or 2, characterized in that, The switching units (26) each have two switching contacts (48), and the switching contacts are connected to the switching lines (44, 46, 66, 68).

11. The ground contact unit according to claim 10, characterized in that, There are two sets of switching lines (44, 46), where one of the switching contacts (48) is connected to one set of switching lines (44) via at least one diode (50), and the other of the switching contacts (48) is connected to the other set of switching lines (46).

12. The ground contact unit according to claim 11, wherein, The switching unit (26) is configured such that if there is at least a predetermined voltage difference between the switching contacts (48), then the switching unit electrically connects the contact area (20) associated with it to the potential (24) associated with it.

13. The ground contact unit according to claim 1 or 2, characterized in that, The ground contact unit (12) has at least one control line (28), and the switching unit (26) has a double - pole switch (36) as a switching element (34), where the double - pole switch (36) is configured such that the control line (28) is electrically connected to a specific potential (24) only when the contact area (20) is connected to the specific potential (24).

14. The ground contact unit according to claim 13, characterized in that, The double - pole switch (36) is configured such that one of the switches (40) in the double - pole switch (36) can electrically connect the control line (28) to the contact area (20), and only when the control line (28) is electrically connected to the contact area (20), the other switch (40) of the double - pole switch (36) electrically connects the contact area (20) to a specific potential (24).

15. The ground contact unit according to claim 1 or 2, characterized in that, The ground contact unit (12) has a first potential (24.1), a second potential (24.2) and a third potential (24.3), where the contact area (20.1) associated with the first potential (24.1) forms a first contact area (20.1), where the contact area (20.2) associated with the second potential (24.2) forms a second contact area (20.2), where the contact area (20.3) associated with the third potential (24.3) forms a third contact area (20.3), wherein the first contact region (20.1) is arranged as a first sub-grid (G U1 ) in the form of a two-dimensional Bravais lattice, the second contact region (20.2) is arranged as a second sub-grid (G U2 ) in the form of a two-dimensional Bravais lattice, and the third contact region (20.3) is arranged as a third sub-grid (G U3 ), wherein the first sub-grid (G U1 ), the second sub-grid (G U2 ), and the third sub-grid (G U3 ) are nested with each other, and wherein the first contact region (20.1), the second contact region (20.2) and the third contact region (20.3) appear alternately in the direction of at least one of the basis vectors of the main grid (G H ) formed through the contact region (20).

16. The ground contact unit according to claim 1, characterized in that, Each of the switching units (26) is respectively provided at each set of switching lines (44, 46, 66).

17. The ground contact unit according to claim 2, characterized in that, The current source is the local power grid.

18. The ground contact unit according to claim 2, characterized in that, For the ground potential, the neutral conductor, the outer conductor, the phase or the positive and / or negative poles of the current source respectively have their own potential (24).

19. The ground contact unit according to claim 5, characterized in that, The contact area (20) is not a PE contact area (25).

20. The ground contact unit according to claim 6, characterized in that, If the switching lines (44, 46, 66, 68) associated with the switching unit (26) are switched in the correct polarity in a common electrical circuit (42), the switching element (34) of the switching unit (26) can electrically connect the corresponding at least one contact area (20) to the potential (24) associated therewith.

21. The ground contact unit according to claim 8, characterized in that, A group of switching lines (44, 46, 66, 68) extends in parallel.

22. The ground contact unit according to claim 8, wherein, The switching unit (26) can be switched only at different potentials on its switching lines (44, 46, 66, 68).

23. The ground contact unit according to claim 9, characterized in that, The angle between the different groups is 90°.

24. The ground contact unit according to claim 9, characterized in that, The angles between the different groups are of the same magnitude.

25. The ground contact unit according to claim 13, characterized in that, The switching unit (26) has a relay.

26. The ground contact unit according to claim 13, characterized in that, The two-way switch (36) is configured such that the control line (28) is electrically connected to the PE potential only when the contact area (20) is connected to a specific potential (24).

27. The ground contact unit according to claim 13, characterized in that, The two-way switch (36) is configured such that one of the switches (40) in the two-way switch (36) can electrically connect the control line (28) to the contact area (20), and only when the control line (28) is electrically connected to the contact area (20), the other switch (40) of the two-way switch (36) connects the contact area (20) to the PE potential.

28. A method for switching the contact area (20) of the ground contact unit (12) according to any one of claims 1 to 27 to a desired potential, the method having the following steps: a) Applying a predetermined voltage with a predetermined corresponding polarity to the switching lines (44, 46, 66, 68), the switching unit (26) associated with the contact area (20) to be switched being applied to the switching lines, whereby the switching unit (26) is actuated such that the contact area (20) is electrically connected to at least one potential (24) associated with the contact area (20), and b) Applying the desired potential to at least one potential (24) associated with the contact area (20) to be switched.

29. The method according to claim 28, wherein A positive voltage is applied to the switching lines (44, 66, 68) of one of the groups, while a negative voltage is applied to the switching lines (46) of the other group.

30. The method according to claim 28 or 29, characterized in that, Determining the voltage on the control line (28), wherein the number of switched and / or unswitched contact areas (20) is inferred from the magnitude of the voltage.

31. The method according to claim 28 or 29, characterized in that Limiting the current of one of the switching lines (44, 46, 66, 68) to which the voltage has been applied such that only a specific number of switching units (26) can be switched via the switching lines (44, 46, 66, 68).

32. The method according to claim 28, having the following step: b) Applying the desired potential via the main disconnect switch (29) or a disconnect switch (27) provided in the base body (16) and / or upstream of the contact area (20) to at least one potential (24) associated with the contact area (20) to be switched.

33. The method according to claim 29, wherein The positive voltage is +12V or +6V.

34. The method according to claim 29, wherein The negative voltage is -12V or -6V.

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