Ground Connection Unit for Vehicle Battery Charging System

Abstract

A ground connection unit (10) for a vehicle battery charging system, comprising a ground-side base (30) and an upper outer wall (12), a receiving space for disposing at least one printed circuit board (28) between the base (30) and the outer wall (12), and a plurality of connection points (14) provided on an outer side of the outer wall (12) for connection to mating connection points on a vehicle side, A ground connection unit (10) in which the connection points (14) are conductively connected to a printed circuit board (28) by electrical wiring, the electrical wiring being formed, at least in part, by a flexible, freely extending connection point bridge (34) configured to spring-like flex toward a base (30).

Description

[Technical field]

[0001] The present invention relates to a ground connection unit for a vehicle battery charging system. [Background technology]

[0002] For electric vehicles, conductive charging systems are known in which electrical wiring is established in an automated manner between a component on the vehicle side (also called a vehicle connection unit) and a component stationary on the ground (also called a ground connection unit).

[0003] For this purpose, electrical connection points are usually provided on the underbody of the vehicle and can be brought into contact with corresponding connection surfaces of the ground connection unit, if required. Summary of the Invention [Problem to be solved by the invention]

[0004] Such a ground connection unit is disclosed, for example, in WO2019 / 052962A1. This ground connection unit has a ground-side base and an upper outer wall, between which a receiving space is formed in which an electronic device is received. At least one printed circuit board is provided, and this printed circuit board is electrically connected to connection points provided on the outside of the outer wall. These connection points approach the vehicle-side connector for electrical coupling when the vehicle needs charging. A large number of these connection points are provided on the upper outer wall, and two or more of them (e.g., among the connection points that connect to the mating connection points) send a charging current when the connector is coupled. The distribution of multiple connection points on the outer wall means that the vehicle does not need to be optimally oriented with respect to the ground connection unit. Only the connection points or a part of them that optimally connect with the mating connection points on the vehicle's connector are finally connected to pass the current.

[0005] As already mentioned, the connection point on the outer wall is electrically connected to a printed circuit board, usually by means of a pin provided at the connection point on its rear side.

[0006] Since the ground connection units are driven, i.e. can be subjected to considerable weight loads, possibly of several tons, these ground connection units need to be constructed robustly so as to function safely for many years, while it must now be ensured that the internal electrical connections of the ground connection units remain intact despite the external mechanical loads. [Means for solving the problem]

[0007] This object is achieved by a ground connection unit for a vehicle battery charging system, comprising a ground base and an upper outer wall, a receiving space in which at least one printed circuit board is arranged being formed between the base and the outer wall, a number of connection points provided on the outside of the outer wall for connection to mating vehicle-side connection points, the connection points being conductively connected to the printed circuit board by electrical wiring, the electrical wiring being formed at least in part by a flexible and freely extending connection point bridge, which is configured to be spring-like deflectable towards the base.

[0008] The flexible and freely extending connection point bridges in the electrical wiring route between the respective connection points on the outer wall and the printed circuit board allow the outer wall to yield itself somewhat elastically when loaded, which does not adversely affect the fatigue strength of the electrical wiring components and their fixing points. The previously considered solution of soldering pins to the printed circuit board and providing a highly stable outer wall is replaced by the present invention, i.e. elasticity is deliberately chosen instead of the rigidity of the system.

[0009] The printed circuit board is preferably accommodated in the receiving space so as to be suspended, and the connection point bridges are attached to one of the upper and lower sides of the printed circuit board. In particular, the connection point bridges are initiated from the printed circuit board, since the connection to the respective elastic connection point bridges can be relatively easily performed in an automated manner. Due to the positioning on the upper or lower side, the respective fastening points on the printed circuit board are mainly subjected to tensile loads from points vertically away from the printed circuit board, and problematic shear loads are not so much generated.

[0010] In a side or top view of the ground connection unit, the connection point bridges may describe at least one circular arc, which changes shape when the respective associated connection points are moved perpendicularly to the upper exterior wall, the connection point bridges being elastically deformed. This arrangement ensures that the connection point bridges themselves are hardly stressed and at the same time act as optimal interference mitigation means between adjacent parts of the electrical wiring. Preferably, the circular arcs are open to the side or top, i.e. include a sideways or upright "U" formed by the connection point bridges. The free ends of the legs form transitions for connecting to adjacent components, e.g. printed circuit boards or pins, or for connecting directly to connection points on the exterior wall.

[0011] A further problem is the secure attachment of the connection point bridges to the adjacent parts of the electrical wiring. According to one variant, the invention provides that the connection point bridges are fixed at their ends to the respective adjacent components by wire bonding, welding or soldering. Alternatively, the connection point bridges can be fixed at their ends to the respective adjacent components by pressing, crimping, clamping or screwing. In wire bonding, a wire, usually made of aluminum, is used and fixed directly to the adjacent components by applying vibration and heat. The wire forms the connection point bridge. This method is characterized by a high long-term stability and the possibility of automation, which is cost-effective. So-called laser bonding can also be applied.

[0012] As already indicated, pins can be provided inside the connection points of the outer wall, which extend towards the associated printed circuit board and constitute part of the respective electrical wiring. The pins can be formed here as separate parts, i.e. not integrally continuing to the connection points. Alternatively, however, the pins can be formed integrally with the connection points on their rear side and integrally continuing thereto by projecting therefrom. At least one respective connection point bridge is provided between the pins and the printed circuit board, which can be elastically deflected as a spring in the longitudinal direction of the pin and electrically connects the pin to the printed circuit board. The pins preferably project vertically from the rear side of the associated contact so as to be displaced vertically when a load is applied to the outer wall.

[0013] If the pins extend beyond the associated printed circuit board, i.e. laterally across its outer wall or through a recess or opening, the connection point bridge can, for example, be very simply attached to the underside of the pin and then extend in the shape of an arc, for example in the shape of an upright U, to the underside of the printed circuit board. This orientation of the connection point bridge has been found to be very advantageous in terms of long-term stability.

[0014] To reduce cycle times in fully automated manufacturing, multiple connection point bridges may be jointly glued or welded or soldered to at least one printed circuit board and / or associated pins.

[0015] The connection point bridge may also be integral with the associated printed circuit board, i.e. the printed circuit board has a type of elastic conductive extension which forms the connection point bridge and whose free end is fixed to the associated pin, so that no separate part is needed to provide the connection point bridge.

[0016] Considering the possibility of a connection bridge failing, providing multiple connection bridges per pin provides additional safety in terms of long-term stability.

[0017] To ensure the positioning of the connection point bridges in the receiving space, at least some, preferably all, of the connection point bridges may be received in a mounting holder accommodated in the receiving space. This mounting holder positions the connection point bridges relative to the at least one printed circuit board and, if present, relative to the pins. In particular, this mounting holder provides an optimal orientation of the connection point bridges in terms of fatigue strength. For example, the U-shaped connection point bridges already mentioned several times above are oriented such that the "U" is, for example, positioned exactly horizontally or vertically. Also, in order to prevent friction between the connection point bridges, the connection point bridges are prevented from connecting with other connection point bridges.

[0018] The pins can be welded to the connection points of the outer wall, in particular by contact welding. If desired, the materials of the connection points and the pins can be different, but this does not necessarily have to be the case.

[0019] The lateral option guides for each pin also provide a constant optimized line orientation for a given bend under load.

[0020] The lateral guides may consist of a retaining plate having a sleeve integrally formed therewith or inserted therein through which the pin extends.

[0021] The printed circuit board may be mounted, for example, by a holder spaced from the base and fixed to an exterior wall to limit relative movement of the electrical wiring when mechanical load is applied to the ground connection unit. The holder may also consist of a retaining plate and a sleeve, but this is optional.

[0022] For this purpose, a pressure plate can be fixed to the outer wall on the one hand and to the at least one printed circuit board on the other hand in order to hold the printed circuit board in a suspended state.

[0023] In general, without being limited to the combination of the above-mentioned features, it is preferred that the printed circuit board is supported floatingly in the receiving space in order to move loads as far away from it as possible. For this purpose, the printed circuit board may be installed, for example, so as to be suspended, possibly with selective support from below, so that the printed circuit board is still movable.

[0024] In a further variant of the invention, the pressure plate and the outer wall are positioned laterally relative to one another by projections which engage in recesses, meaning that a mechanical connection is provided.

[0025] Furthermore, between the outer wall and the base, there may be support parts for vertically supporting the outer wall on the base, the support parts, or in some cases a single support part, being for ensuring the mechanical stability of the outer wall relative to the base, in order to prevent the outer wall from being overly springy when a vehicle is driven over it.

[0026] The support component may be integrally formed with the base and may have a pin-like configuration.

[0027] A conductive intermediate plate may be provided on the rear side of the exterior wall to electrically couple multiple protective earth connection points on the rear side of the exterior wall. These line sections are connected to the associated protective earth connection points on the one hand and to the printed circuit board by a shared connection point bridge on the other hand. This allows the number of connection point bridges to be reduced.

[0028] Further features and advantages of the present invention will become apparent from the following drawings and the following description taken in conjunction with the following drawings. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a schematic top view of a ground connection unit according to the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional side view of a ground connection unit according to the present invention. [Diagram 3]FIG. 3 is a schematic cross-sectional view of a ground connection unit according to a first embodiment of the present invention. [Figure 4] FIG. 4 is a schematic cross-sectional view of a ground connection unit according to a second embodiment of the present invention. [Diagram 5] FIG. 5 is a schematic cross-sectional view of a ground connection unit according to a third embodiment of the present invention. [Figure 6] FIG. 6 is a schematic cross-sectional view of a ground connection unit according to a fourth embodiment of the present invention. [Figure 7] FIG. 7 is a top view of a portion of the ground connection unit according to FIG. 6, including the connection points, the underlying connection point bridge and the printed circuit board. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] 1 shows a ground connection unit 10 for a vehicle battery charging system. The ground connection unit 10 is placed on the ground or laid at ground level on private or public land and has a plate-like shape with a relatively low height.

[0031] In simple terms, charging a battery works like this: A hybrid or electric vehicle moves over a ground unit. Then a vehicle connection unit, which has a number of connection points protruding downward, moves downward relative to the ground connection unit. The ground connection unit determines which of the many connection points exposed on its top surface are flush with mating connection points on the vehicle. Power is activated to some of these connection points so that the charging process can begin.

[0032] Some details of the ground connection unit 10 are described below.

[0033] The ground connection unit 10 has an upper outer wall 12 on which are disposed a number of connection points 14 arranged in a matrix. The connection points 14 are arranged in a pattern, which in the illustrated embodiment is arranged in the form of a two-dimensional Bravais lattice, or more precisely a hexagonal lattice.

[0034] In the illustrated example, the ground connection unit 10 comprises three ground connections 16, 18, 20 which are connected to respective connections of a local power grid. Each of the ground connections 16, 18, 20 provides a different electrical potential.

[0035] The ground connection unit 10 is provided with potential levels 22, 24, 26 for each potential (see FIG. 2). Although only three potential levels are depicted, a different number of potential levels can also be provided. Of course, the potential levels are isolated from each other.

[0036] In the illustrated exemplary embodiment, the potential levels 22-26 are, for example, conductive layers of a printed circuit board 28 illustrated in Fig. 3. The printed circuit board 28 is disposed in the interior space of the ground connection unit 10.

[0037] This receiving space is bounded towards the ground by a so-called ground-side base 30, either the base 30 having a side wall, the outer wall 12 having a side wall towards the base 30, or a separate side wall is provided connecting the outer wall 12 and the base 30 and providing a liquid-tight receiving space inside the ground connection unit 10.

[0038] When the vehicle connection unit moves over the ground connection unit 10, multiple connection points of the vehicle connection unit connect with several connection points 14 of the ground connection unit 10. The corresponding paired connection points are detected, some of these connection points are activated by respective circuits of the ground connection unit 10, while other connection points remain disconnected, and the charging process can begin.

[0039] The internal structure of the ground connection unit 10, particularly its mechanical and electrical structure, will now be described in more detail.

[0040] The outer wall 12 has a number of depressions in the region of the connection points 14 which are bonded to the rear surface of the outer wall 12 in the region of the bottom of each depression and are flush with the upper surface of the outer wall 12 .

[0041] The connection points 14 are, for example, small stainless steel plates. An electrical wiring starting from the rear side of the connection points 14 consists in this case of several parts which lead to corresponding connection points on the printed circuit board 28. One part of this electrical wiring is, for each connection point 14, a brass or steel pin 32 which has a plate-like end which is fixed to the rear side of the connection point 14, for example by soldering, welding or gluing. In the area of ​​the plate-like expansion of the pin 32, the pin 32 is further held and sealed to the outer wall 12 by a potting compound 36.

[0042] The pins 32 extend toward the base 30, preferably perpendicular to the upper surface of the outer wall 12, and preferably extend a distance beyond the printed circuit board 28 (either laterally beyond or through a recess or opening in the printed circuit board 28).

[0043] The underside of the printed circuit board 28 is provided with one or more flexible, freely extending connection point bridges 34 that extend to the underside of the printed circuit board 28 and electrically connect each pin 32 with a corresponding connection point on the printed circuit board 28. Without the connection point bridge 34 or bridges 34, the pins 32 would not make electrical contact with the printed circuit board 28.

[0044] As explained, the connection point bridge 34 or bridge 34 is made to extend freely and flex freely like a spring towards the base 30. This means that the connection point bridge 34 compensates for the changing distance between the lower end wall of the pin 32 and the underside of the printed circuit board 28 when the vehicle is positioned on the ground connection unit 10 and the outer wall 12 flexes minimally like a spring, moving the corresponding pin 32 downward.

[0045] The connection point bridge 34 has an arc shape, in particular a U-shape. In this example, the "U" is an upright U-shape with the open side facing upwards. Alternatively, it may be a lying U-shape.

[0046] The connection point bridge 34 is attached to the pin 32 by welding or soldering, but preferably by adhesive bonding, here in particular by wire bonding.

[0047] The connection point bridge is attached to the printed circuit board using the same types of attachment methods.

[0048] As an alternative to the embodiment shown in FIG. 3, the pins 32 could, of course, terminate in the area of ​​or short of the top side of the printed circuit board 28, so that the connection point bridges 34 extend from the underside of each pin 32 to the top side of the printed circuit board 28 in an arc, again as a "U."

[0049] A holder 40 is provided, which has a pressure plate 42 and a sleeve-like integrally formed lateral guide 38. The pin 32 on the left side of FIG. 3 extends through the sleeve-like lateral guide 38 of the holder 40. The pressure plate 42 contacts the underside of the outer wall 12. An extension 44 formed integrally with the pressure plate 42 extends from the pressure plate 42 to the printed circuit board 28, which is fixed to the extension 44. In this way, the printed circuit board 28 is connected in a hanging manner to the outer wall 12 via the holder 40, and the holder 40 is fixed to the outer wall 12 by a fastening element 46.

[0050] A shield plate 48 may be attached to the holder 40 below the retaining plate 42. As can be seen in FIG.

[0051] The holder 40 is positioned laterally relative to the outer wall 12 by a recess, more specifically a projection 50 which projects into a complementary recess (in this case the recess of the plate 42).

[0052] In order to obtain mechanical support for the exterior wall 12 when loaded by the vehicle, a number of support parts 52 are provided. The support parts 52 extend from the upper surface of the base 30 to the exterior wall 12 or, if the holder 40 and / or the shielding plate 48 are provided below the exterior wall 12, as in the embodiment according to Fig. 3, to the lower surface of the corresponding plate or plates. In this way, a mechanical bridge between the base 30 and the exterior wall 12 is achieved.

[0053] 3, the support parts 52 may be integrally or multiply connected to one another by a connecting part 54, such as a plate. Alternatively, the connecting part 54 may be integrally connected to the base 30, in which case the support parts 52 integrally protrude upwardly from the base 30.

[0054] In the illustrated embodiment, the right pin 32 is made of steel. The pin 32 extends through an anchor cone 60 housed in a conical recess in the outer wall 12. Adjacent to the underside of the anchor cone 60 is a ferrite sleeve 62 which is housed in a bush-like enlargement 64 of the lateral guide 38.

[0055] Again, the connection point bridge 34 resides under the pin 32. The ferrite sleeve 62 and anchor cone conduct the magnetic field used to position and align the vehicle connection unit.

[0056] In the illustrated embodiment, one or more relays 70 are mounted on an upper surface of the printed circuit board 28 .

[0057] The embodiment according to Fig. 4 differs from the embodiment according to Fig. 3 with respect to the following features, so that only the differences are described and identical or functionally identical parts are given the previous reference numerals: In contrast to the embodiment according to Fig. 3, no pins are provided here, but rather flexible and freely extending connection point bridges 34 extend from the underside of each connection point 14 to the printed circuit board 28. The attachment to the respective connection points 14 and to the printed circuit board 28 is effected by any of the methods previously described.

[0058] In the variant according to FIG. 4, the connection point bridge 34 is fixed to the upper side of the printed circuit board 28 .

[0059] In this case, the printed circuit board 28 is located relatively close to the exterior wall 12, but spaced from the exterior wall 12 so that the relay 70 or other bulky electronic components are mounted on the underside of the printed circuit board 28.

[0060] Again, of course, each flexible, freely extending connection point bridge 34 is configured in an arc shape to accommodate as much movement as possible without placing a tensile load on the connection point bridges 34. The connection point bridges 34 are here in the shape of a sideways "U".

[0061] In this example, only one node bridge 34 is shown per node 14, but it would be easy to provide more than one node bridge 34 per node 14.

[0062] According to FIG. 4, support parts are not shown, but can of course be present.

[0063] Furthermore, a mounting holder may be provided which, so to speak, receives all or a number of groups of connection point bridges 34 and positions them relative to the printed circuit board 28 or the connection points 14, so that soldering, welding or bonding can be performed automatically, preferably also with multiple simultaneous tools, for jointly attaching all or a number of connection point bridges to the printed circuit board and / or the connection points 14 and / or the pins 32. The mounting holder can remain in the receiving space for positioning the connection point bridges 34 relative to one another during operation.

[0064] As further shown in FIG. 4, the support component 52 may be integrally formed with the base 30 .

[0065] In the embodiment shown in Figure 5, an electrically conductive intermediate plate 148 is fixed to the rear side of the exterior wall 12. This intermediate plate 148 is in electrical connection with a number of protective earth connection points, also called PE connection points.

[0066] The intermediate plate 148 is connected to the pins 32, for example by means of fastening screws 150, and may at the same time be used for electrical connections. One connection point bridge 34 is sufficient to electrically connect all protective earth connection points to the printed circuit board 28.

[0067] Parts and portions already described are labeled with the reference numerals already described and need not be described separately.

[0068] In the embodiment according to Figures 6 and 7, the connection point bridge 34 is "U" shaped in top view rather than in side view (see Figure 7), and is therefore a horizontal "U".

[0069] Here too - although this should not be understood in a limiting sense - a connection bridge 34, which may be a pressed part, is screwed under the pin 32. Here, optionally, the pin 32 may merge integrally into the contact 14 and project from it at the rear. Of course, other contact connections between one connection point bridge 34 and an adjacent part, i.e., pin 32 or printed circuit board 28, can also be provided in general, without being limited to any embodiment, for example a pressing or crimping as symbolized by line 152 in FIG. 7, or a clamp between the connection points 14 or pins 32 of the two parts.

Claims

1. An on - ground connection unit (10) for a vehicle battery charging system, comprising an upper - side base (30) and an upper outer wall (12), with a receiving space for arranging at least one printed circuit board (28) formed between the base (30) and the outer wall (12), and comprising a plurality of connection points (14) provided outside the outer wall (12) for connecting to counterpart connection points on the vehicle side. The connection points (14) are conductively connected to the printed circuit board (28) by electrical wiring, and the electrical wiring is formed by a flexible freely - extending connection - point bridge (34) configured to be at least partially elastically bent in a spring - like manner towards the base (30). The on - ground connection unit (10) is characterized by this.

2. The on - ground connection unit (10) according to claim 1, wherein the connection - point bridge (34) is attached to one of the upper - surface side and the lower - surface side of the associated printed circuit board (28).

3. In a side view or a top view of the on - ground connection unit (10), the connection - point bridge (34) is elastically deformed respectively to draw at least one arc whose shape changes when the associated connection point moves perpendicularly to the upper outer wall (12). The on - ground connection unit (10) according to claim 1 or 2 is characterized by this.

4. The on - ground connection unit (10) according to claim 1 or 2, wherein the connection - point bridge (34) has its ends fixed to adjacent components respectively by wire bonding, welding, soldering, pressing, crimping, clamping, or screwing.

5. Pins (32) are provided inside the connection points (14) on the outer wall (12). The pins (32) are formed as separate parts or integrally formed on the back - surface side of the connection points (14) and protrude from the connection points (14). The pins (32) extend towards the associated printed circuit board (28) and form part of each electrical wiring. At least one respective connection - point bridge (34) extends between the pin (32) and the printed circuit board (28). The connection - point bridge (34) can be elastically bent in a spring - like manner in the longitudinal direction of the pin (32) to electrically connect the pin (32) to the printed circuit board (28). The on - ground connection unit (10) according to claim 1 is characterized by this.

6. The ground connection unit (10) according to claim 5, characterized in that the pin (32) extends beyond the associated printed circuit board (28).

7. The ground connection unit (10) according to claim 5 or 6, characterized in that a plurality of connection point bridges (34) are jointly adhered or welded or soldered to at least one printed circuit board (28) and / or the associated pins (32).

8. The ground connection unit (10) according to claim 5 or 6, characterized in that the connection point bridge (34) is integrally formed on the associated printed circuit board (28) and is fixed to the associated pin (32) by its respective free end.

9. The ground connection unit (10) according to claim 5 or 6, characterized in that a plurality of connection point bridges (34) are provided for each pin (32).

10. The ground connection unit (10) according to claim 5 or 6, characterized in that at least some, preferably all, of the connection point bridges (34) are received in a receiving space and received by a mounting holder, the mounting holder positioning the connection point bridges (34) relative to at least one printed circuit board (28) and the pins (32).

11. The ground connection unit (10) according to claim 5 or 6, characterized in that the pin (32) is welded to the connection point (14) of the outer wall (12), in particular by contact welding.

12. The ground connection unit (10) according to claim 5 or 6, characterized in that a lateral guide (38) is provided for each pin (32).

13. The ground connection unit (10) according to claim 12, characterized in that the lateral guide (38) is attached to a holding plate (42) or formed by a sleeve integrally formed with the holding plate (42), and the pin (32) extends into the sleeve.

14. The ground connection unit (10) according to claim 13, characterized in that the pressing plate (42) is fixed on the one hand to the outer wall (12) and on the other hand to at least one printed circuit board (28) in order to hold the printed circuit board (28).

15. The ground connection unit (10) according to claim 13, characterized in that the pressing plate (42) and the outer wall (12) are positioned laterally relative to each other by a projection (50) engaging in a recess.

16. The above-ground connection unit (10) according to claim 1 or 2, characterized in that a support component (52) for supporting the outer wall (12) vertically on the base (30) extends between the outer wall (12) and the base (30).

17. The above-ground connection unit (10) according to claim 16, characterized in that the support component (52) is integrally formed with the base (30).

18. The above-ground connection unit (10) according to claim 1 or 2, characterized in that a conductive intermediate plate is attached to the back side of the outer wall (12), a plurality of connection points (14) which are protective earth connection points are electrically coupled to the intermediate plate, and the intermediate plate is connected to the printed circuit board (28) by a connection point bridge (34).

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