Ground contact unit for a vehicle battery charging system

Abstract

The invention relates to a ground contact unit (10) for a vehicle battery charging system, having a base (14) on the ground side, a front wall (16) arranged thereabove, electronics (22) that are arranged between the base (14) and the front wall (16) in a receiving space (18), and a plurality of contacts (20) provided on the outside of the front wall (16) for making contact with mating contacts on the vehicle side. The front wall (16) has a contact receiving field (24) in which the contacts (20) are arranged, and a housing section (26) which lies outside the contact receiving field (24). The contact receiving field (24) is designed as a separate part from the housing section (26) and forms an electrical insulation part between the contacts (20) and the housing section (26).

Description

[0001] Ground contact unit for vehicle battery charging system

[0002] The invention relates to a ground contact unit for a vehicle battery charging system.

[0003] For electrically powered vehicles, conductive charging systems are known in which an electrical connection is automatically established between a vehicle-side part (also called vehicle contact unit) and a stationary part lying on the ground (called ground contact unit).

[0004] For this purpose, electrical contacts are usually present on the underbody of the vehicle, which can be brought into contact with the corresponding contact surfaces of the ground contact unit when required.

[0005] Such a ground contact unit is known, for example, from WO 2019 / 052962 A 1. This ground contact unit has a base at the bottom and a front panel positioned above it, between which a compartment is formed to house the electronics. At least one circuit board is provided, which is electrically connected to contacts located on the outside of the front panel. A vehicle-side connector then moves to these contacts to connect electrically when the vehicle needs to be charged. Numerous such contacts are provided on the front panel; two, three, or more of these contacts (i.e., those contacts that make contact with mating contacts) then transmit the charging current when the connector is connected. The multiple contacts distributed across the front panel mean that the vehicle does not need to be optimally aligned with the ground contact unit.Only those contacts, or some of those contacts, that are in sufficiently good contact with the counterpart contacts on the vehicle's connector will eventually be switched to conduct current.

[0006] As mentioned, the contacts on the front panel are electrically connected to the circuit board, usually via pins located on the back of the contacts. Since the ground contact unit may be installed outdoors and thus exposed to environmental influences, there is a need to design these ground contact units in such a way that they function reliably for many years and can be supplied cost-effectively.

[0007] The problem is solved by a ground contact unit for a vehicle battery charging system, comprising a base on the ground and a front panel positioned above it, forming the top of the ground contact unit. A recess is formed between the base and the front panel, in which electronics, including at least one printed circuit board, are positioned. The ground contact unit also has several contacts on the outside of the front panel for connecting to corresponding contacts on the vehicle. These contacts are electrically connected to the printed circuit board. The front panel has a contact area in which the contacts are arranged and a housing section located outside the contact area. The contact area is designed as a separate part from the housing section and forms an electrical insulation element between the contacts and the housing section.Furthermore, the contact area is made of a contact area material and the housing section is made of a housing material.

[0008] It was found according to the invention that a short circuit between the contacts and the housing section is reliably prevented by means of the contact area, which is designed as an electrical insulating element. Since the contact area is designed separately from the housing section, both the contact area and the housing section can be more easily and individually adapted to different requirements. Furthermore, this design has the advantage that, unlike the prior art, where the entire front panel always has to be replaced in the event of damage, the contact area and the housing section can be replaced or recycled independently of each other with minimal effort if necessary. In this way, the base contact unit can be manufactured, repaired, and recycled cost-effectively.Furthermore, the base contact unit is designed to be so robust that the internal electronics are permanently protected from environmental influences, thus ensuring a long service life. The contacts can be made of an electrically conductive material that exhibits stronger adhesion to the contact surface material than to the housing material, particularly when the contact surface material is directly adjacent to the contact material. Because the contact surface material adheres better to the contacts than to the housing material, a particularly high sealing effect is achieved, especially independent of thermal stress or expansion of the front panel. This effect is particularly effective when the coefficient of thermal expansion of the contact surface material is closer to that of the contacts and / or the circuit board than to that of the housing material.

[0009] In one embodiment, the contacts are tightly embedded in the contact reception area, in particular wherein the contact reception area completely encloses each contact in a circumferential direction. This results in a particularly tight connection between the contacts and the contact reception area, and provides particularly good protection for the internal electronics.

[0010] In this configuration, the contact field material can at least partially abut one side of the contacts facing the base. This ensures that the contact is embedded circumferentially and at one end face within the contact field material, resulting in a particularly secure and tight seal. In one embodiment, the contact field material differs from the housing material. This allows the materials to be selected according to their specific requirements. In particular, the housing material can be a material with exceptionally high strength and resistance, while the contact field material offers a higher degree of sealing. Additionally or alternatively, the housing material can have a lower tracking resistance than the contact field material. This design results in a particularly robust base contact unit and provides lasting protection for the internal electronics against environmental influences.The contact field material is a thermoset, e.g., an epoxy resin, a thermoplastic polymer, or a ceramic, which permanently provides a reliable connection between the contacts and the contact field.

[0011] Furthermore, the contacts may be made of an electrically conductive material in the form of a metal alloy, making them particularly robust and durable. In particular, the electrically conductive material differs from the housing material.

[0012] According to one embodiment, the housing material is a metal alloy, a thermoplastic, or a fiber-reinforced plastic, in particular fiber-reinforced polybutylene terephthalate or fiber-reinforced polyamide. In this way, the housing section can be manufactured cost-effectively and robustly.

[0013] In an alternative embodiment, the contact field material and the housing material are identical, making the front panel particularly cost-effective to manufacture.

[0014] Furthermore, the contact area can be tightly connected to the housing section, in particular by material, form and / or force-fit, so that the electronics in the receiving space are reliably protected from environmental influences such as moisture and dust.

[0015] Furthermore, the contact area can be designed to be separable from the housing section without damage. In particular, the contact area and contacts can be designed as a module. This allows the contact area and the housing section to be replaced or recycled independently of each other with minimal effort, if necessary.

[0016] According to one embodiment, the contact plate is a plate-shaped body. In particular, the housing section has an opening into which the contact plate is inserted, thus closing the opening. This makes the base contact unit particularly compact and flat. According to another embodiment, the electronics comprise contact electronics and charging electronics. Specifically, the contact electronics are arranged between the contact plate and the base, while the charging electronics are arranged between the housing section and the base. By arranging the charging electronics laterally offset from the contact electronics under the housing section, the distance between the contact plate and the base can be reduced, thereby making the base contact unit flatter.

[0017] In this case, the contact electronics can be connected to the charging electronics via a multiplexer for signal transmission.

[0018] Furthermore, the contact electronics can include relays for switching the individual contacts.

[0019] The charging electronics may include or incorporate safety and control electronics.

[0020] According to one embodiment, the charging electronics includes an electronic device for protective conductor testing, insulation testing, current and voltage measurement, as a communication interface and / or for a residual current protection circuit.

[0021] In an embodiment not covered by the present invention, which represents a further invention, the ground contact unit for a vehicle battery charging system has a base at the bottom and a front wall arranged above it, forming a top surface. A receiving space is formed between the base and the front wall, in which electronics with at least one printed circuit board are positioned. The ground contact unit also has several contacts provided on the outside of the front wall for connecting to corresponding contacts on the vehicle side. The contacts are electrically connected to the printed circuit board. The front wall has a contact receiving area in which the contacts are arranged and a housing section located outside the contact receiving area. The contact receiving area forms an electrical insulating element between the contacts and the housing section.Furthermore, the contact area is formed from the same contact area material, and the housing section is formed from the same housing material. The contact area and the housing section are integrally integrated, with the contact area material being identical to the housing material. By forming the contact area and housing section as a single unit, the front panel is particularly simple and cost-effective. This also results in a high degree of sealing. Additionally, the contact area, which acts as an electrical insulator, reliably prevents short circuits between the contacts and the housing section.This embodiment can have the same features as the embodiment according to the invention with the advantages described above, provided that the corresponding feature does not necessarily require a separate design of the contact field and the housing section.

[0022] Further advantages and features will become apparent from the following description and the accompanying drawings. These show:

[0023] - Figure 1 shows a schematic exploded view of a ground contact unit according to the invention,

[0024] - Figure 2 shows the ground contact unit in a perspective view

[0025] Figure 1,

[0026] - Figure 3 shows a section of the ground contact unit in a sectional view along the plane A - A in Figure 2,

[0027] - Figure 4 shows a perspective view of another embodiment of the ground contact unit, which illustrates a further invention, and

[0028] - Figure 5 shows a section of the ground contact unit in a sectional view along plane B - B in Figure 4.

[0029] The detailed description below, in conjunction with the accompanying drawings, in which identical numbers refer to identical elements, is intended to describe various embodiments of the disclosed subject matter and is not meant to represent the only embodiments. Each embodiment described in this disclosure serves only as an example or illustration and should not be construed as preferable or advantageous over other embodiments.

[0030] All features disclosed below with reference to the exemplary embodiments and / or the accompanying figures can be combined alone or in any subcombination with features of the aspects of the present disclosure, including features of preferred embodiments, provided that the resulting combination of features is meaningful to a person skilled in the art.

[0031] Figure 1 shows a ground contact unit 10 for a vehicle battery charging system. This ground contact unit 10 (see Figure 2) is placed on the ground or laid flush with the ground on private or public property and has a plate-like shape with a relatively low profile. In short, charging a battery works as follows: The hybrid or electric vehicle is driven over the ground contact unit. A vehicle contact unit with several counter-contacts projecting from the underside is then moved downwards against the ground contact unit. The ground contact unit determines which of its numerous exposed contacts on the top side have optimal contact with the corresponding vehicle contacts. The power supply to some of these contacts is then activated, allowing the charging process to begin.

[0032] The structure of the ground contact unit 10 is explained in more detail below.

[0033] The floor contact unit 10 has a housing 12 with a base 14 on the bottom and a front wall 16 forming a top 52 of the floor contact unit 10, between which a receiving space 18 is formed inside the housing 12, several contacts 20 and electronics 22 which are arranged in the receiving space 18.

[0034] Furthermore, the ground contact unit 10 has a power connection (not shown) via which it is connected to a local power grid during operation.

[0035] The upper front wall 16 is formed in multiple parts and has a contact receiving field 24 in which the contacts 20 are arranged in a pattern, and a housing section 26 which adjoins the contact receiving field 24 and accommodates it in the illustrated embodiment.

[0036] The contact field 24 is formed from a contact field material which in the present embodiment is a thermoset.

[0037] In an alternative embodiment, the contact field material is an epoxy resin, a thermoplastic polymer, or a ceramic.

[0038] In principle, the contact field 24 can be made of any electrically insulating material.

[0039] The housing section 26 is formed from a housing material which in the present embodiment is a fiber-reinforced plastic, for example fiber-reinforced polybutylene terephthalate or fiber-reinforced polyamide.

[0040] In principle, the housing section 26 can be made of any material, in particular a metal alloy or a thermoplastic material.

[0041] The contact plate material and the housing material are fire-resistant. In particular, the contact plate material and the housing material have a fire resistance rating of V-0 according to UL 94, preferably at least V-2, and / or a glow wire resistance of 800°C.

[0042] The housing section 26 has a first, continuous part 28 and a frame part 30 extending from it, defining an opening 32, which surrounds the contact receiving field 24, which is inserted into the opening 32 and closes it.

[0043] In the present embodiment, the contact receiving field 24 is formed separately from the housing section 26 and is arranged in the opening 32 in the frame part 30, which is designed to be complementary to the contact receiving field 24. Thus, the contact receiving field 24 fits snugly in the opening 32 and essentially closes it completely (see Figure 2).

[0044] The contact field 24 is plate-shaped and has a circumferential flange 34, on which the contact field 24 rests on the inside of the frame part 30, so that the opening 32 is tightly closed.

[0045] To ensure a particularly high level of tightness, a seal can be arranged between the frame part 30 and the contact area 24, in particular the circumferential flange 34.

[0046] The seal can be a cord profile seal, a sealing tape (for example made of butyl), a sealing ring or a wet seal (for example polyurethane foam).

[0047] The contact field 24 is attached to the housing section 26, in particular to the frame part 30, by means of fastening means such as screws.

[0048] In this way, the housing section 26 and the contact field 24 can be separated from each other without damage.

[0049] Preferably, the contact field 24 and the contacts 20 are designed as a module to simplify assembly and disassembly.

[0050] In another embodiment, the contact receiving field 24 and the housing section 26 are additionally or alternatively connected to each other by means of a material bond, for example by means of an adhesive bond or a welding bond.

[0051] The contact plate material may differ from the housing material.

[0052] In an alternative embodiment, the contact receiving field 24 and the housing section 26 are made of the same material, i.e., the contact receiving field material and the housing material are identical.

[0053] In all embodiments, the electrical contacts 20 are arranged externally in the upper front wall 16, so that they can be contacted by the vehicle-side mating contacts during a charging process. In this context, the electronics 22 (see Figure 1) has contact electronics 36 and charging electronics 38, which are connected to the contact electronics 36 via a multiplexer 40 for signal transmission.

[0054] In the illustrated embodiment, the contact electronics 36 are completely separated from the charging electronics 38 by the multiplexer 40, i.e., all signals exchanged between the contact electronics 36 and the charging electronics 38 pass through the multiplexer 40.

[0055] In an alternative embodiment, the contact electronics 36 and the charging electronics 38 can be additionally connected to the multiplexer 40 for signal transmission, so that the multiplexer 40 only partially separates the contact electronics 36 and the charging electronics 38.

[0056] In the illustrated embodiment, the contact electronics 36, the charging electronics 38 and the multiplexer 40 are arranged on a common circuit board 42.

[0057] Of course, in an alternative embodiment, the contact electronics 36, the charging electronics 38 and the multiplexer 40 can be arranged on several circuit boards 42, in particular on one or more circuit boards 42 which are individually assigned to the respective components 36, 38, 40.

[0058] The contact electronics 36 has several relays 44 which are configured to switch the contacts 20 individually, in particular between a current-conducting state and a non-current-conducting state.

[0059] The charging electronics 38 has an electronic device 46, which is set up here for insulation testing.

[0060] Additionally or alternatively, the electronic device 46 can be configured for parts of the protective conductor testing, for current and voltage measurement, as a communication interface and / or for a residual current protection circuit.

[0061] In principle, the electronic device 46 can include any safety and control electronics configured for one or more safety and control functions of the ground contact unit 10. For example, the charging electronics 38 include at least some components similar to those found in wall-mounted charging stations for charging a vehicle battery.

[0062] The contact electronics 36 are arranged in the Z direction between the socket 14 and the contact receiving field 24, while the charging electronics 38 are arranged in the Z direction between the socket 14 and the continuous part 28 of the housing section 26. More precisely, the charging electronics 38 are not arranged in the Z direction between the socket 14 and the contact receiving field 24, but laterally offset from it.

[0063] In this context, the contacts 20 are electrically connected to the circuit board 42 via electrical conductors.

[0064] In the present embodiment, the electrical conductors have pins 48 (see Figure 3) which each extend in the direction Z towards a contact 20.

[0065] The pins 48 are connected to the circuit board 42, for example, via flexible, free-running contact bridges (not shown), which are designed to be springable in the opposite direction Z, i.e. towards the base 14, and form a further part of the electrical lines.

[0066] In an alternative embodiment, the contacts 20 can be connected at least partially directly to each other, i.e. without connection to the circuit board 42.

[0067] The pins 48, for example, are made of a copper alloy.

[0068] The contacts 20 can be made of corrosion-resistant steel, nickel-plated bronze or nickel-plated brass.

[0069] In an alternative embodiment, the contacts 20 can be made of any electrically conductive material.

[0070] Preferably the contacts 20 are made of a metal alloy, for example stainless steel or nickel-plated brass.

[0071] Furthermore, in another embodiment, the contacts 20 can have a ceramic layer on their circumference. In the present embodiment, the contacts 20 are formed by circular plates (see Figure 3), each of which is received in a complementarily shaped recess 50 in the contact receiving field 24.

[0072] Of course, in an alternative embodiment, the contacts 20 can each be designed as desired.

[0073] Each contact 20 is positively embedded in the contact receiving field 24 and completely enclosed in the circumferential direction U (see Figure 2) by the contact receiving field material, so that the recess 50 on the top 52 is completely closed by the corresponding contact 20 and the contact receiving field 24 and thus the front wall 16 is sealed.

[0074] The outer surfaces 54 of the contacts 20 are exposed and flush with the top surface 52.

[0075] In the present embodiment, the inner surfaces 56 of the contacts 20 facing the base 14 and a section of the pins 48 are also enclosed by the contact receiving field material.

[0076] In this context, the contact field material is an electrical insulator and preferably has a tracking resistance with a CTI value of 600 for DC voltages in the range of 1000 V and a minimum CTI value of 400 for AC voltages of 230 / 400 V.

[0077] Thus, the contact receiving field 24 forms an electrical insulation part 58 between the contacts 20 and the housing section 26, which electrically insulates the contacts 20 from the housing section 26.

[0078] Furthermore, the contact area 24 and the housing section 26 are fire-resistant. In particular, the contact area 24 and the housing section 26 have a fire resistance rating of V-0 according to UL 94, preferably at least V-2, and / or a glow wire resistance of 800°C.

[0079] The contacts 20 can be bonded to the contact receiving field 24 by means of a material bond, for example by potting. However, the receiving space 18 always has a cavity for the electronics 22, i.e., the receiving space 18 is not completely filled.

[0080] In the present embodiment, the contact field material is directly adjacent to the contacts 20 and the housing.

[0081] The materials can be chosen such that the adhesion between the contact field material and the contact material is greater than the adhesion between the contact material and the housing material.

[0082] This ensures that the contacts 20 are effectively fixed in the recesses 50 and that the front wall 16 is reliably and permanently sealed.

[0083] In this way, a ground contact unit 10 is provided for a vehicle battery charging system that is robust and cost-effective to manufacture.

[0084] Furthermore, the multi-part design of the front wall 16 ensures that the contact field 24 and the housing section 26 can be replaced or recycled independently of each other with minimal effort.

[0085] With reference to Figures 4 and 5, a ground contact unit 10 according to a further embodiment is now described. The same reference numerals are used for the components known from the embodiment above, and reference is made to the preceding explanations in this respect.

[0086] In contrast to the embodiment shown in Figures 1 to 3, the contact receiving field 24 in the present embodiment is integrally formed with the housing section 26, i.e., the contact receiving field 24 merges seamlessly into the housing section 26 or the frame part 30. The section of the upper front wall 16 that forms the contact receiving field 24 is indicated in Figure 4 by a dashed frame.

[0087] Apart from the one-piece design of the upper front wall 16, the embodiment shown in Figures 1 to 3 and the embodiment shown in Figures 4 to 5 are identical in design. This applies in particular to the internal structure, such as the electronics 22, which is only shown in Figure 1.

[0088] In Figure 5, which shows the upper front wall 16 in a one-piece embodiment, the course of the housing section 26 and the contact receiving field 24 with flange 34 are indicated by a dashed line.

[0089] Of course, in embodiments with a one-piece upper front wall 16, the flange 34 can be omitted.

[0090] In this way, a ground contact unit 10 is provided for a vehicle battery charging system that is robust and, due to the one-piece design of the front wall 16, can be manufactured cost-effectively and is particularly dense.

Claims

1. Patent claims 1. Ground contact unit (10) for a vehicle battery charging system, comprising a base (14) on the ground and a front wall (16) arranged above it, forming a top (52), wherein a receiving space (18) is formed between the base (14) and the front wall (16), in which an electronics unit (22) with at least one printed circuit board (42) is positioned, and with several contacts (20) provided on the outside of the front wall (16) for contacting vehicle-side mating contacts, wherein the contacts (20) are electrically connected to the printed circuit board (42), wherein the front wall (16) has a contact receiving field (24) in which the contacts (20) are arranged, and a housing section (26) which lies outside the contact receiving field (24), characterized in that the contact receiving field (24) is designed as a part separate from the housing section (26) and an electrical insulation part (58) is provided between the contacts (20) and the housing section. (26) forms,wherein the contact receiving field (24) is made of a contact receiving field material and the housing section (26) is made of a housing material.

2. Ground contact unit (10) according to claim 1, characterized in that the contacts (20) are formed from an electrically conductive material, wherein the electrically conductive material has a stronger adhesion with the contact receiving field material than with the housing material, in particular wherein the contact receiving field material is directly adjacent to the contact material.

3. Ground contact unit (10) according to one of the preceding claims, characterized in that the contacts (20) are tightly embedded in the contact receiving field (24), in particular wherein the contact receiving field (24) completely encloses each contact (20) in a circumferential direction (U).

4. Ground contact unit (10) according to claim 3, characterized in that the contact receiving field material borders at least sectionally on a side (56) of the contacts (20) which faces the base (14).

5. Ground contact unit (10) according to one of the preceding claims, characterized in that the contact field material is an epoxy resin, a thermoset, a thermoplastic polymer or a ceramic.

6. Ground contact unit (10) according to one of the preceding claims, characterized in that the contacts (20) are formed from an electrically conductive material, wherein the electrically conductive material is a metal alloy, in particular wherein it differs from the housing material.

7. Ground contact unit (10) according to one of the preceding claims, characterized in that the housing material is a metal alloy, a thermoplastic polymer or a fiber-reinforced polymer, in particular fiber-reinforced polybutylene terephthalate or fiber-reinforced polyamide.

8. Ground contact unit (10) according to one of the preceding claims, characterized in that the contact receiving field material differs from the housing material.

9. Ground contact unit (10) according to one of the preceding claims, characterized in that the contact receiving field (24) is tightly connected to the housing section (26), in particular by material, form and / or force connection.

10. Ground contact unit (10) according to one of the preceding claims, characterized in that the contact receiving field (24) can be separated from the housing section (26) without damage, in particular wherein the contact receiving field (24) is designed as a module with the contacts (20).

11. Ground contact unit (10) according to one of the preceding claims, characterized in that the contact receiving field (24) is a plate-shaped body, in particular wherein the housing section (26) has an opening (32) into which the contact receiving field (24) is inserted and the opening (32) is closed.

12. Ground contact unit (10) according to one of the preceding claims, characterized in that the electronics (22) comprise contact electronics (36) and charging electronics, in particular wherein the contact electronics (36) are arranged between the contact receiving field (24) and the base (14), while the charging electronics (38) are arranged between the housing section (26) and the base (14).

13. Ground contact unit (10) according to claim 12, characterized in that the contact electronics (36) is connected to the charging electronics (38) via a multiplexer (40) for signal transmission.

14. Ground contact unit (10) according to claim 12 or 13, characterized in that the contact electronics (36) has relays (44) for switching the individual contacts (20).

15. Ground contact unit (10) according to one of claims 12 to 14, characterized in that the charging electronics (38) includes an electronic device (46) for It features protective conductor testing, insulation testing, current and voltage measurement, a communication interface and / or a residual current protection circuit.

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