Stationary inductive charging device

Abstract

The present invention relates to a stationary inductive charging device (1) for an inductive vehicle charging system for charging the battery of a battery-powered vehicle, comprising a coil (2) for generating an alternating electromagnetic field, the coil (2) extending in a coil plane (7) perpendicular to the height direction (Z) of the inductive charging device (1) and formed by at least one electrical conductor (8), and a metal bottom plate (3) for mounting the inductive charging device (1) on a base (4), the bottom plate plane (9) extending parallel to the coil plane (7). The present invention relates to an inductive charging device (1) comprising a bottom plate (3), a plastic cover (5) extending in a cover plane (12) parallel to the coil plane (7) and supported on the bottom plate (3) via side walls (13) extending all around the periphery, and a plurality of magnetically conductive conductive plates (6) made of a soft magnetic material, each extending between each coil (2) and the bottom plate (3) in a conductive plate plane (16) parallel to the coil plane (7). A simplified structure is obtained when the inductive charging device (1) is formed as a passively cooled stationary inductive charging device (1), the inductive charging device (1) has a plurality of heat conducting elements (17), each of which supports at least one of the plurality of conductive plates (6) on the bottom plate (3) and is heat conductingly connected to the bottom plate (3), and the coil (2) is directly or indirectly heat conductingly connected to the cover (5).

Description

[Technical Field]

[0001] The present invention relates to a stationary inductive charging device for an inductive vehicle charging system for charging the batteries of battery-powered vehicles according to the preamble of claim 1 .

[0002] Such an inductive vehicle charging system comprises a stationary inductive charging device, sometimes called a ground assembly or a ground assembly, which is generally located in a fixed position, for example, in a vehicle parking lot, and connected to a power grid; and a mobile inductive charging device, sometimes called a vehicle assembly or a vehicle assembly, which is located on each vehicle, particularly on the vehicle underfloor. The mobile inductive charging device is then appropriately connected to the vehicle's battery, for example, via a corresponding vehicle charging device. To charge the battery, the vehicle is positioned with its mobile inductive charging device relative to the stationary inductive charging device, so that electrical energy can be transferred from the stationary inductive charging device to the mobile inductive charging device by induction, i.e., via an alternating electromagnetic field. The inductive vehicle charging system eliminates the need for a charging plug that must be inserted into a vehicle charging socket.

[0003] The stationary inductive charging device described above is known, for example, from U.S. Patent Application Publication No. 2018 / 0374624, and includes at least one coil for generating an alternating electromagnetic field, the coil extending substantially in a coil plane perpendicular to the height of the inductive charging device and formed by at least one electrical conductor. The stationary inductive charging device also includes a metal bottom plate for mounting the inductive charging device on a base, the bottom plate extending in a bottom plate plane parallel to the coil plane. The stationary inductive charging device also includes a plastic cover, the cover extending in a cover plane parallel to the coil plane and supported on the bottom plate via a circumferential side wall, the cover having a lower cover surface facing each coil and a front cover surface opposite each coil. Furthermore, the stationary inductive charging device has a plurality of magnetically conductive conductive plates made of soft magnetic material, each extending between each coil and the bottom plate in a conductive plate plane that extends parallel to the coil plane.

[0004] During operation of such a stationary inductive charging device, a relatively large amount of waste heat is generated, mainly in each coil and conductive plate, due to the high power. The high temperatures usually pose problems for electronic components, such as power electronics or control devices, housed in the stationary inductive charging device for its operation. In order to achieve the longest possible life for these temperature-sensitive components and to avoid overheating of these components, the heat generated during operation of the inductive charging device must be dissipated.

[0005] The aforementioned U.S. Patent Application Publication No. 2018 / 0374624 discloses a stationary inductive charging device configured as an actively cooled stationary inductive charging device. For this purpose, the stationary inductive charging device has a heat exchanger that is arranged vertically between a bottom plate and a conductive plate and is circulated by a coolant. For this purpose, the heat exchanger is integrated into the cooling circuit. The structural cost of integrating such a heat exchanger is relatively large.

[0006] The problem addressed by the present invention is to provide an improved embodiment or at least one alternative embodiment of the stationary inductive charging device of the type described above, which is particularly advantageous in that sufficient heat dissipation can be achieved with relatively low expenditure in terms of material, assembly and costs.

[0007] This problem is solved according to the invention by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0008] The present invention is based on the general idea of ​​configuring the stationary inductive charging device as a passively cooled stationary inductive charging device, thereby completely eliminating the structural expenditure required for active cooling. To achieve sufficient passive cooling, the present invention proposes providing substantially or substantially separate heat conduction paths within the stationary inductive charging device for cooling or heat dissipation of each coil and for cooling or heat dissipation of the conductive plate. By discharging the heat from both main heat sources separately via separate heat conduction paths, it is possible to avoid, in particular, the accumulation of heat from both heat sources within the stationary inductive charging device. The present invention proposes discharging the heat generated by each coil to the surrounding environment via the cover, while discharging the heat generated by the conductive plate via the bottom plate to the foundation on which the bottom plate rests. Specifically, the present invention proposes that the inductive charging device includes a plurality of heat-conducting elements, each of which supports at least one of the plurality of heat-conducting plates on the bottom plate and is thermally connected to the bottom plate. This provides a heat-conducting path from the heat-conducting plate to the bottom plate, allowing heat from the heat-conducting plate to be conducted from the bottom plate to the foundation on which the bottom plate is placed. Furthermore, each coil is directly or indirectly thermally connected to the cover, providing a heat-conducting path from each coil to the cover, allowing heat to be conducted from the cover to the surrounding environment.

[0009] The base on which the bottom plate or stationary inductive charging device rests may be flush with or coplanar with the ground on which a vehicle with a compatible mobile inductive charging device can rest or travel. The base may also be sunk, elevated, or raised relative to the ground. For example, the base may be sunk below the ground level of a vehicle parking lot until the cover of the stationary inductive charging device is flush with the ground.

[0010] In this specification, "configuration" is synonymous with "design." Therefore, the expression "configured to" is synonymous with the expression "designed to."

[0011] The heat conducting element may be glued to the bottom plate and to the conducting plate, in which case a heat conducting adhesive is especially used.

[0012] Advantageously, it may be specified that each heat conducting element is in indirect contact with each conducting plate via a heat conducting layer and / or a heat conducting adhesive or in direct contact, thereby achieving improved heat transfer.

[0013] According to an advantageous embodiment, the cover is supported on the bottom plate via side walls extending all around the periphery, which may optionally be formed directly on the cover, so that the cover together with the side walls form a hood which defines the interior of the device in height and transversely to this height direction. This gives the cover an additional function. Furthermore, by this measure, the surface area of ​​the cover exposed to the surrounding environment is increased by the surface area of ​​the side walls located on the outside, thereby improving the heat transfer of the cover to the surrounding environment.

[0014] In another embodiment, it may be specified that the side wall has a flange extending all around, by which the side wall is fixed and supported to the bottom plate. That is, the bottom plate is formed separately from the side wall and does not have any part of the side wall. In relation to the above-mentioned embodiment, this means that the side wall is completely formed on the cover and is provided on the cover for heat radiation to the surrounding environment. Optionally, it may also be specified that the flange has a groove extending all around, in which a seal extending all around is arranged. This allows the interior of the device to be sealed against the surrounding environment. Insofar as the side wall is integrally formed on the cover, it may also be made of plastic.

[0015] Particularly advantageous is an embodiment in which the inductive charging device includes a reinforcing plate for reinforcing the cover, the reinforcing plate extending in a reinforcing plate plane parallel to the plane of the coil, having an upper reinforcing plate surface facing the cover and a lower reinforcing plate surface opposite the cover, made of a dielectric casting compound, and heat-conductively connected to each conductor formed as a strand. Furthermore, it is specified that the upper reinforcing plate surface is heat-conductively connected to the lower surface of the cover, thereby heat-conductively connecting the coil to the cover via the reinforcing plate. At the same time, the reinforcing plate significantly reinforces the cover, allowing high vertical loads, such as when a battery-powered vehicle to be charged by the stationary inductive charging device drives over the stationary inductive charging device, to be introduced into the cover without impairing the integrity of the device's interior space formed by the cover and the bottom plate. Furthermore, the reinforcing plate allows the cover to be manufactured with a reduced wall thickness, which significantly reduces the mass and, therefore, the thermal inertia of the cover. For example, the cover may be made of glass fiber reinforced plastic with a wall thickness of 2 to 5 mm. Advantageously, the reinforcing plate has a higher thermal conductivity than the cover, thereby improving heat transfer from each coil to the cover. To this end, the material for the reinforcing plate or the casting compound may be selected appropriately to achieve the desired thermal conductivity. The conductor formed as a strand comprises a plurality of conductive wires.

[0016] In an advantageous embodiment, it may be specified that a reinforcing plate is arranged between the cover and the coil in the height direction, which helps to divide the heat dissipation into two different paths.

[0017] Additionally or alternatively, it may be provided that the reinforcing plate plane extends in the height direction between the cover plane and the coil plane, which also assists in dividing the heat dissipation into the two different paths.

[0018] In another advantageous embodiment, it may be specified that the reinforcement plate is in indirect contact with the cover via a heat-conducting layer and / or a heat-conducting adhesive or in direct contact with the cover, by which means the heat transfer is improved.

[0019] Furthermore, in this embodiment, the inductive charging device may optionally have multiple support elements, each supported on the reinforcing plate on the one hand and on the bottom plate and / or one of the multiple conductive plates on the other hand. The support elements support the load of the reinforcing plate against the bottom plate directly or indirectly via the conductive plates. This unloads the side walls, which can also be realized with reduced thickness.

[0020] According to an advantageous embodiment, the casting material of the reinforcing plate has a plastic matrix in which dielectric reinforcing fibers and / or dielectric heat-conducting particles can be embedded. The reinforcing fibers significantly improve the mechanical stability of the reinforcing plate. The heat-conducting particles significantly improve the thermal conductivity of the reinforcing plate. The casting material can be a plastic, synthetic resin, or hydraulic binder. The reinforcing fibers can be, for example, glass fibers, aramid fibers, or ceramic fibers. The heat-conducting particles can be, for example, ceramics, in particular aluminum oxide, aluminum nitrite, or silicon nitrite.

[0021] Dielectric, as used herein, means poorly or non-conductive or electrically insulating.

[0022] In an advantageous embodiment, the reinforcing plate has at least one reinforcing element made of a fiber structure, which extends in a plane parallel to the plane of the reinforcing plate and is embedded in the casting compound. The fiber structure may be, for example, a woven fabric, warp knitted fabric, weft knitted fabric, or spun fabric in the form of a sheet or strands of fiber. The fibers may be configured as short or long fibers. In addition to dielectric fibers, conductive fibers, such as carbon fibers, may also be used as the fibers, as long as the reinforcing element itself does not form a conductive structure that would impair the alternating electromagnetic field of the respective coil.

[0023] In another embodiment, the reinforcing plate may have a plurality of plate openings penetrating the reinforcing plate in the height direction, and these plate openings may be filled with a dielectric heat-conducting material that is in direct contact with the underside of the cover and in direct or indirect contact with each strand. The plate openings, in combination with the heat-conducting material, significantly improve heat conduction from each coil to the cover. A suitable heat-conducting material may be, for example, a heat-conducting paste.

[0024] According to another embodiment, each strand may contact and / or be fixed to the underside of the reinforcing plate at least partially via a strand holder. In this case, the strand holder may be shaped so as to be in surface contact with each strand and with the underside of the reinforcing plate. In this case, the strand holder is in contact with the heat-conducting material in the area of ​​the aforementioned plate openings. The surface contact of the strand holder with the reinforcing plate on the one hand and with each strand on the other hand improves heat transfer between the strand and the reinforcing plate. For the surface contact with the strands, the strand holder is shaped complementarily to the outer contour of each strand. The contact of the strand holder with the heat-conducting material located in the aforementioned plate openings also improves heat transfer to the cover.

[0025] Advantageously, the wire holder may be made of a thermally conductive material, which improves heat transfer from the coil toward the cover. Additionally or alternatively, the wire holder may be attached to the underside of the reinforcing plate and / or to each wire by a thermally conductive adhesive. The thermally conductive adhesive also improves heat transfer at the joint, thereby simultaneously fulfilling the retention function. Such a thermally conductive adhesive has a good thermal conductivity, for example, of at least 0.5 W / m·K, i.e., watts per meter per degree Kelvin, and preferably at least 1.0 W / m·K.

[0026] In another embodiment, it may be specified that the entire strand holder is made of thermally conductive adhesive, i.e., each strand is fixed to the underside of the reinforcing plate by thermally conductive adhesive, with enough thermally conductive adhesive to provide surface contact between the underside of the reinforcing plate and each strand.

[0027] A further function of the wire holder is obtained from the arrangement of openings for accommodating the wires, which makes it particularly easy, when the wire holder is arranged, to hold and fix the wires in a flat coil shape that is particularly suitable for the construction of a particularly effective alternating electromagnetic field.

[0028] According to another embodiment, a dielectric heat-conducting material may be arranged between the cover and the reinforcing plate, the heat-conducting material being in contact with the underside of the cover and the upper side of the reinforcing plate, improving heat transfer between the reinforcing plate and the cover. The heat-conducting material preferably has a thermal conductivity greater than or at least equal to that of the cover and the reinforcing plate.

[0029] In an advantageous embodiment, the dielectric heat-conducting material may be liquid at normal ambient temperatures and the operating temperature of the inductive charging device. In this case, the heat-conducting material is correspondingly a heat-conducting liquid, such as an oil, in particular an insulating oil. When a liquid heat-conducting material is used, it is clear that a sufficient seal is provided between the reinforcing plate and the cover or side wall to prevent the heat-conducting material from flowing into the device interior.

[0030] In another embodiment, the underside of the cover can have a three-dimensional underside structure on its surface, while the upper side of the reinforcing plate can have a three-dimensional upper side structure on its surface. The underside and upper side structures can then be complementary to each other and thus form-fittingly engage with each other. The three-dimensional structuring significantly increases the surface area on each side, thereby improving heat transfer between the reinforcing plate and the cover.

[0031] According to an advantageous embodiment, the reinforcing plate can be attached directly to the cover by means of a casting compound, in particular by directly fastening the reinforcing plate to the cover by casting the compound, which results in a particularly strong bond between the reinforcing plate and the cover.

[0032] Alternatively, the reinforcing plate can be manufactured separately from the cover and placed on the cover or side wall, and in particular fixed to the cover or side wall. For example, a separately manufactured reinforcing plate can be fixed to or supported on the side wall via corresponding supports formed on the side wall. In this case, the aforementioned heat-conducting liquid can be used, in particular, between the upper side of the reinforcing plate and the underside of the cover. Alternatively, a separately manufactured reinforcing plate can be bonded to the cover with a heat-conducting adhesive, and then this heat-conducting adhesive can be applied to the underside of the cover and the upper side of the reinforcing plate. This also improves heat transfer between the cover and the reinforcing plate.

[0033] In another embodiment, each strand may be in direct contact with the underside of the reinforcing plate, at least in the region of each coil, which allows for high heat transfer.

[0034] Advantageously, the underside of the reinforcing plate has a wire receiving structure that is shaped complementary to the wires, and in this wire receiving structure each wire extends partially into the reinforcing plate in the height direction and can be in surface contact with the underside of the reinforcing plate. The surface contact between the reinforcing plate and the wires significantly improves heat transfer.

[0035] It may further be specified that the reinforcing plate is attached to each strand by means of a thermally conductive adhesive, in particular that the adhesive is pressed into the structure of the strand, which significantly increases the contact surface area and correspondingly improves heat transfer.

[0036] According to another embodiment, at least in the region of each coil, each strand can be arranged partially recessed in the height direction in the reinforcing plate, and the reinforcing plate can be directly attached to each strand by the casting compound. This can be achieved by the casting compound of the reinforcing plate being fixed to each strand by casting. For this purpose, the strands can be placed, for example, as inserts in a casting mold for producing the reinforcing plate. This also allows the casting compound to be pressed at least superficially into the structure of the strands, which increases the contact surface area and improves heat transfer.

[0037] In another embodiment, at least in the region of each coil, each strand can be arranged so as to be sufficiently recessed in the height direction in the stiffening plate, so that the casting compound coats each strand in a closed manner in the circumferential direction of the strand. This can be achieved in particular by positioning the strands in a casting mold for producing the stiffening plate, so that the casting compound can then coat the strands in the circumferential direction. This allows any heat emitted by each strand to be directly introduced into the stiffening plate.

[0038] In another embodiment, the inductive charging device includes at least one coil support, which holds each strand of each coil, and which extends in a coil support plane parallel to the coil plane and between the reinforcing plate and the conductive plate in the height direction. The coil support simplifies assembly of the inductive charging device.

[0039] In another embodiment, it may be specified that at least one of the support elements supports the reinforcing plate to one of the conductive plates and is arranged coaxially with the heat conducting element that supports the conductive plate to the bottom plate. A force transmission path is thus provided between the reinforcing plate and the bottom plate, extending through the support element, the conductive plate, and the heat conducting element. In this case, it is clear that the heat conducting element is constructed sufficiently stably, which is possible without difficulty, since metallic materials can be used for the conductive plate's surfaces opposite the respective coils and for the central area magnetically shielded by the conductive plate itself.

[0040] The heat conducting element may be made from aluminum, which is particularly associated with a high thermal conductivity, with a thermal conductivity of more than 180 W / m·K, for improved load carrying capacity.

[0041] In another embodiment, at least one of the support elements supports the reinforcing plate directly on the bottom plate and is routed between adjacent conductive plates transversely to the height direction. In principle, this embodiment can be combined with the previously described embodiments. However, it is preferred that all support elements are supported on one of the conductive plates or on the bottom plate.

[0042] The heat conducting element has a relatively high thermal conductivity, for example at least 100 W / m·K. For example, the heat conducting element may be made of aluminum nitrite. In particular, the heat conducting element has a higher thermal conductivity than the conducting plate and / or the bottom plate.

[0043] The support element may preferably be made of a dielectric material and may be glued to the reinforcing plate and / or the conductive or bottom plate.

[0044] Each support element has a central longitudinal axis extending parallel to the height direction, which extends parallel to the central longitudinal axis of each heat conduction element, which also extends parallel to the height direction. In one case, the central longitudinal axes are coaxial and coincident with one another. In another case, the central longitudinal axes are spaced apart transversely to the height direction.

[0045] According to another advantageous embodiment, the inductive charging device may have a thermally conductive layer arranged between the bottom plate and the foundation in the height direction, whereby the bottom plate is supported on the foundation via the thermally conductive layer. The thermally conductive layer can compensate for irregularities on the bottom plate's lower surface facing the foundation and / or on the upper surface of the foundation facing the bottom plate, thereby significantly improving heat transfer between the bottom plate and the foundation. A so-called thermal interface material (TIM for short) may be used as the thermally conductive layer, which has a high thermal conductivity of, for example, more than 1 W / m·K, preferably at least 5 W / m·K. In this case, the thermally conductive layer may be relatively thin, for example, less than 5 mm, preferably less than 2 mm. In this case, the thermally conductive layer may be made of a relatively hard material, such as hard rubber, screed, another hydraulic binder, a curable resin, or an adhesive.

[0046] Advantageously, the inductive charging device may be characterized in that the total thermal resistance between each conductive plate and the bottom plate is less than 6 K / W, preferably less than 4 K / W. Optionally, furthermore, the total thermal resistance between the bottom plate and the base may be specified to be less than 0.4 K / W, preferably less than 0.2 K / W.

[0047] Additionally or alternatively, the inductive charging device may be characterized in that the total thermal resistance between each strand and the cover or between each strand and the surrounding environment, in particular air, is less than 1 K / W, preferably less than 0.8 K / W, in particular less than 0.7 K / W.

[0048] The conductive plates preferably consist of a magnetically soft and preferably electrically insulating or only slightly conductive, i.e., dielectric, material. The relative permeability μ is preferably μ > 2, in particular μ > 1000. A suitable material is, for example, ferrite, and therefore the conductive plates are often also called ferrite plates.

[0049] Further important features and advantages of the invention emerge from the dependent claims, the drawings and the corresponding description of the drawings based on the drawings.

[0050] Naturally, the features mentioned above and those further described below can be used not only in the combinations mentioned respectively, but also in other combinations or alone, without departing from the scope of the invention as defined by the claims. The separately named components mentioned above and further described below of a superordinate unit, e.g., mechanism, device or assembly, may form separate components or elements of the unit in question, or may be integral regions or sections of the unit, even if shown differently in the drawings.

[0051] Preferred embodiments of the present invention are illustrated in the drawings and explained in detail in the following description, wherein like reference numerals refer to identical or similar or functionally identical components. [Brief explanation of the drawings]

[0052] [Figure 1] 1 is a highly simplified schematic cross-sectional view of a stationary inductive charging device in one embodiment; [Figure 2] 1 is a highly simplified schematic cross-sectional view of a stationary inductive charging device in one embodiment; [Figure 3] 1 is a highly simplified schematic cross-sectional view of a stationary inductive charging device in one embodiment; [Figure 4] 1 is a highly simplified schematic cross-sectional view of a stationary inductive charging device in one embodiment;

[0053] 1 to 4, a stationary inductive charging device 1, which is a component of an inductive vehicle charging system for charging the battery of a battery-electric vehicle, comprises at least one coil 2 for generating an alternating electromagnetic field, a metal bottom plate 3 for mounting the inductive charging device 1 on a base 4, a plastic cover 5, and a plurality of magnetically conductive plates 6 made of a soft magnetic material. The inductive charging device 1 has a flat structure defining a height direction Z that extends vertically in the cross-sectional views of FIGS. 1 to 4. Each coil 2 extends in a coil plane 7 that extends perpendicular to the height direction Z. Each coil 2 is formed by at least one electrical conductor embodied as a strand 8. The bottom plate 3 extends in a bottom plate plane 9 that extends parallel to the coil plane 7, i.e., also perpendicular to the height direction Z. The bottom plate 3 thereby has a bottom plate upper surface 10 facing each coil 2 and a bottom plate lower surface 11 opposite each coil 2 and used for placing on the foundation 4. The cover 5 extends in a cover plane 12 extending parallel to the coil plane 7, and therefore this cover plane 12 also extends perpendicular to the height direction Z. The cover 5 is supported on the bottom plate 3 via side walls 13 extending all around, and has a cover lower surface 14 facing each coil 2 and a cover upper surface 15 opposite each coil 2. The conductive plate 6 extends in a conductive plate plane 16 extending parallel to the coil plane 7, and this conductive plate plane 16 also extends perpendicular to the height direction Z. In this case, the conductive plate plane 16 is located between each coil plane 7 and the bottom plate plane 9 in the height direction Z.

[0054] The inductive charging device 1 proposed in this specification is configured as a passively cooled stationary inductive charging device 1.

[0055] For this purpose, the inductive charging device 1 has a plurality of heat-conducting elements 17, each of which supports at least one of the plurality of conductive plates 6 on the bottom plate 3 and is thermally connected to the bottom plate 3. Furthermore, each of the coils 2 is directly or indirectly thermally connected to the cover 5.

[0056] In the embodiment shown in the drawings, the side walls 13 are formed directly on the cover 5, so that the cover 5 forms a hood together with the side walls 13. The hood defines an interior chamber 18 of the device in the height direction Z and transversely to the height direction Z. The side walls 13 are supported by the bottom plate 3, so that the interior chamber 18 is further defined in the height direction Z by the bottom plate 3. The respective coils 2, the conductive plate 6 and the heat conducting element 17 are arranged inside the interior chamber 18 of the device.

[0057] In all embodiments shown in the drawings, the side wall 13 has a circumferential flange 19 by means of which the side wall 13 is fixed and supported on the bottom plate 3. Corresponding fixing elements, such as screws, are not shown in the drawings. In all examples, the flange 19 has a circumferential groove 20 in which a circumferential seal 21 is arranged.

[0058] 1 to 4, the inductive charging device 1 shown in these figures further comprises a reinforcing plate 22, which serves to reinforce the cover 5 and extends in a reinforcing plate plane 23 that runs parallel to the coil plane 7 and thus perpendicular to the height direction Z. The reinforcing plate 22 reinforces or strengthens the thin cover 5 to an extent that each vehicle can overcome the inductive charging device 1. The reinforcing plate 22 has an upper reinforcing plate surface 24 that contacts the lower cover surface 14 and a lower reinforcing plate surface 25 opposite the cover 5. The reinforcing plate 22 is made of a dielectric casting compound 26 and is thermally connected to each of the wires 8. Furthermore, the upper reinforcing plate surface 24 is thermally connected to the lower cover surface 14. In the simplest case, this can be achieved by direct contact or abutment between the reinforcing plate 22 and the cover 5.

[0059] Furthermore, the inductive charging device 1 shown in the figures has a plurality of support elements 27, each of which is supported on the one hand by the reinforcing plate 22 and, depending on the embodiment, on the other hand by the bottom plate 3 and / or by one of the plurality of conductive plates 6. In the examples of Figures 1, 2 and 4, all of the illustrated support elements 27 are supported on one of the plurality of conductive plates 6. In the example of Figure 3, all of the illustrated support elements 27 are supported on the bottom plate 3. The support elements 27 are preferably designed to be dielectric, i.e. are made of a particularly dielectric material.

[0060] The casting compound 26 may have a plastic matrix in which dielectric reinforcing fibers and / or dielectric heat-conducting particles are embedded, thereby achieving the highest possible rigidity and stability as well as the highest possible thermal conductivity for the reinforcing plate 22. In the example of FIG. 1, the reinforcing plate 22 further comprises a reinforcing element 28, which consists of at least one fiber structure and extends in a reinforcing element plane 29 that runs parallel to the reinforcing element plane 23 and thus also perpendicular to the height direction Z. The reinforcing element 28 is completely embedded in the casting compound 26. For this purpose, the reinforcing element 28 can be inserted into a casting mold during the casting of the casting compound. The fiber structure can advantageously be a planar woven fiber fabric. In the illustrated configuration, dielectric fibers are preferably used.

[0061] 4, the reinforcing plate 22 may have a plurality of plate openings 30, each of which passes completely through the reinforcing plate 22 in the height direction Z. Advantageously, the plate openings 30 are filled with a heat-conducting material 31. In this case, the positioning of the plate openings 30 is selected so that the heat-conducting material 31 is in direct contact with the cover underside 14 on the one hand and in direct or indirect contact with each of the strands 8.

[0062] According to FIG. 4, at least one wire holder 32 may be provided for positioning and holding each strand 8, which wire holder 32 is at least partially in contact with and / or fixed to the underside 25 of the reinforcing plate. The wire holder 32 is shaped so that it is in surface contact with each strand 8, on the one hand, and with the underside 24 of the reinforcing plate, on the other hand. In particular, the wire holder 32 may be adapted to the rounded, in particular circular, cross-section of the strands 8 shown in the drawing. The aforementioned plate openings 30 are advantageously positioned within the reinforcing plate 22 so that the wire holder 32 is in contact with the heat-conducting material 31 in the area of ​​the plate openings 30. The wire holder 32 itself may consist of a heat-conducting material. It is also possible to attach the wire holder 32 to the underside 24 of the reinforcing plate and / or to each strand 8 by means of a heat-conducting adhesive. Alternatively, the strand holder 32 can be fabricated directly from a thermally conductive adhesive, which is then applied to the reinforcing plate 22 and each strand 8 .

[0063] 2 and 3 show an embodiment in which the cover lower surface 14 has a three-dimensional lower surface structure 33 on its surface, while the reinforcing plate upper surface 24 has a three-dimensional upper surface structure 34 on its surface. In this case, the lower surface structure 33 and the upper surface structure 34 are formed complementary to each other so that they form-fit with each other. This significantly increases the contact area between the cover 5 and the reinforcing plate 22.

[0064] In the embodiment shown in Figure 3, a dielectric heat-conducting material 35 is disposed between the cover 5 and the reinforcing plate 22, and the heat-conducting material 35 is in contact with the cover lower surface 14 and the reinforcing plate upper surface 24. The heat-conducting material 35 may be, for example, a thermally conductive adhesive. However, it is particularly advantageous if the dielectric heat-conducting material 35 is formed as a dielectric heat-conducting liquid that is liquid at least at normal ambient temperatures and the operating temperature of the inductive charging device 1. The heat-conducting material 35 displaces air between the cover lower surface 14 and the reinforcing plate upper surface 24, thereby improving heat transfer.

[0065] 1 and 2, the reinforcing plate 22 is directly attached to the cover 5 by the potting compound 26 itself. In particular, for this purpose, the potting compound 26 is fixed to the cover 5 by casting. In this case, in this embodiment, no heat-conducting material 35 is present between the cover 5 and the reinforcing plate 22.

[0066] 3 and 4, the reinforcing plate 22 may be manufactured separately from the cover 5 and then inserted into the cover 5 and fixed thereto and / or to the side wall 13. In FIG. 4, purely by way of example, the side wall 13 is formed with a plurality of supports 36 via which the reinforcing plate 22 is supported on the side wall 13 and thereby positioned on the cover 5. Additionally or alternatively, the reinforcing plate 22 may be adhered to the cover 5 by means of a thermally conductive adhesive 37, which in this case is attached to the cover lower surface 14 and the reinforcing plate upper surface 24.

[0067] 1 and 2, each wire 8 is in direct contact with the underside 25 of the reinforcing plate. For this purpose, the underside 25 of the reinforcing plate may have a wire receiving structure 38 that is complementary to each wire 8, in which each wire 8 partially penetrates the reinforcing plate 22 in the height direction Z and is in surface contact with the underside 25 of the reinforcing plate. It is clear that in this case, a longer wire section is always in surface contact with the underside 25 of the reinforcing plate inside the wire receiving structure 38. In particular, the wire receiving structure 38 may also be configured helically if the wires 8 extend helically. In the embodiment shown in FIG. 2, each wire 8 penetrates deeper into the reinforcing plate 22 than in the embodiment shown in FIG. 1.

[0068] In principle, the reinforcing plate 22 may be attached to each strand 8 by means of a heat-conducting adhesive (not shown). This may be achieved, for example, in the embodiment shown in Figure 1. Alternatively, it is also possible to pour a potting compound 26 which is then fixed to each strand 8, so that the reinforcing plate 22 is attached directly to each strand 8 by the potting compound 26 itself. This may be the case, for example, in the embodiment shown in Figure 2.

[0069] In the embodiment shown in Fig. 3, each of the wires 8 is disposed so as to be fully recessed in the height direction Z within the reinforcing plate 22. As a result, the casting material 26 closes or fully covers each of the wires 8 in the circumferential direction U. In Fig. 3, the circumferential direction U is representatively indicated only in the rightmost section of the wire 8.

[0070] Even in this sunken arrangement, it is clear that each strand 8 is led out from the reinforcing plate 22 at an appropriate point, thereby forming each coil 2 or electrically connecting each coil 2.

[0071] 1 and 4, the inductive charging device 1 further comprises a coil support 39, on which each strand 8 of each coil 2 is held. In this case, the coil support 39 extends in a coil support plane 40, which extends parallel to the coil plane 7 and, in particular according to FIG. 1, may coincide with the coil plane 7. In this case, the coil support 39 extends in the height direction Z between the reinforcing plate 22 and the conductive plate 6.

[0072] 1, 2 and 4, all of the illustrated support elements 27 are supported by one respective conductive plate 6 and are arranged coaxially with respect to the heat conducting elements 17 which support this conductive plate 6 on the bottom plate 3. This results in the reinforcing plate 22 being supported indirectly on the bottom plate 3 via the support elements 27, i.e. via the conductive plate 6 and the heat conducting elements 17.

[0073] 3 shows an example in which all the support elements 27 are supported on the bottom plate 3. For this purpose, the support elements 27 extend transversely to the height direction Z between adjacent conductive plates 6. In this configuration, the support elements 27 support the reinforcing plate 22 directly on the bottom plate 3.

[0074] In the embodiment of Figures 1 and 3, the bottom plate 3 rests directly on the foundation 4 with its bottom plate lower surface 11. In contrast to this, Figures 2 and 4 show an embodiment in which a thermally conductive layer 41 is arranged between the bottom plate 3 and the foundation 4 in the height direction Z. As a result, the bottom plate 3 is supported on the foundation 4 via this thermally conductive layer 41. It is clear that other embodiments may also be provided with such a thermally conductive layer 41.

[0075] The heat transfer between the bottom plate 3 and the foundation 4 can additionally be improved by further measures. For example, the bottom plate 3 can be screwed to the foundation 4. This allows for an improved pressing of the bottom plate 3 to the foundation 4, which in turn promotes heat transfer, regardless of whether the heat-conducting layer 41 is present or not. Furthermore, the screw connection itself can be readily designed in advance to contribute to the heat transfer. For example, metal plugs can be used.

[0076] Furthermore, the bottom plate 3 can also be extended laterally beyond the side wall 13 on at least one side of the inductive charging device 1 transversely to the height direction Z, thereby providing an additional surface, on the one hand, for heat transfer to the base 41 and, on the other hand, for heat radiation to the surrounding environment 42. In particular, it is also possible for at least one cooling body to be mounted on the bottom plate 3 outside the device chamber 18, which allows additional heat radiation to the surrounding environment 42 via a large surface area.

[0077] The stationary inductive charging device 1 proposed herein is characterized in that the inductive charging device 1 is configured to be passively cooled, which is achieved by providing two separate heat transfer paths within the inductive charging device 1. One heat transfer path conducts heat from each coil 2 to the cover 5, which radiates the heat to the surrounding environment 42. The other heat transfer path conducts heat from the conduction plate 6 to the bottom plate 3, which then introduces the heat into the base 4.

Claims

1. A stationary inductive charging device (1) for an inductive vehicle charging system for charging the battery of a battery-electric vehicle, comprising: at least one coil (2) for generating an alternating electromagnetic field, the coil (2) defining a coil plane (7) extending perpendicular to a height direction (Z) of the inductive charging device (1) and formed by at least one electrical conductor (8); a bottom plate (3) made of metal and extending in a bottom plate plane (9) parallel to the coil plane (7); a cover (5) made of plastic, extending in a cover plane (12) parallel to the coil plane (7), and having a cover lower surface (14) facing each of the coils (2) and a cover upper surface (15) opposite each of the coils (2); a plurality of magnetically conductive conductive plates (6) made of soft magnetic material, each extending between each of the coils (2) and the bottom plate (3) in a conductive plate plane (16) extending parallel to the coil plane (7); In an inductive charging device (1), The inductive charging device (1) is formed as a passively cooled stationary inductive charging device (1), The inductive charging device (1) has a plurality of heat conducting elements (17), each of which supports at least one of the plurality of conductive plates (6) on the bottom plate (3) and is thermally connected to the bottom plate (3); Each of the coils (2) is directly or indirectly thermally connected to the cover (5). An inductive charging device (1).

2. 2. The inductive charging device (1) according to claim 1, characterized in that each of the heat conducting elements (17) is in indirect contact with each of the conductive plates (6) via a heat conducting layer (41) and / or a heat conducting adhesive (37) or in direct contact with each of the conductive plates (6).

3. The cover (5) is supported on the bottom plate (3) via a side wall (13) extending all around the periphery, The side walls (13) are formed directly on the cover (5), so that the cover (5) and the side walls (13) form a hood, which defines the interior chamber (18) of the device in the height direction (Z) and transversely to the height direction (Z).

3. An inductive charging device (1) according to claim 1 or 2, characterized in that it is

4. The inductive charging device (1) has a reinforcing plate (22) for reinforcing the cover (5), the reinforcing plate (22) extending in a reinforcing plate plane (23) extending parallel to the coil plane (7), having a reinforcing plate upper surface (24) facing the cover (5) and a reinforcing plate lower surface (25) opposite the cover (5), made of a dielectric casting material (26) and thermally connected to each of the conductors formed as strands (8); The upper surface (24) of the reinforcing plate is thermally connected to the lower surface (14) of the cover; The inductive charging device (1) may in particular have a plurality of support elements (27), each of which is supported on the one hand by the reinforcing plate (22) and on the other hand by the bottom plate (3) and / or one of the plurality of conductive plates (6). Inductive charging device (1) according to any one of claims 1 to 3, characterized in that it is

5. 5. The inductive charging device (1) according to claim 4, characterized in that the reinforcing plate (22) is arranged between the cover (5) and the coil (2) in the height direction (Z).

6. 6. An inductive charging device (1) according to claim 4 or 5, characterized in that the reinforcing plate plane (23) extends in the height direction (Z) between the cover plane (12) and the coil plane (7).

7. 7. The inductive charging device (1) according to claim 4, wherein the reinforcing plate (22) is in indirect contact with the cover (5) via a thermally conductive layer (41) and / or a thermally conductive adhesive (37) or is in direct contact with the cover (5).

8. 8. The inductive charging device (1) according to claim 4, wherein the potting material (26) of the reinforcing plate (22) has a plastic matrix in which dielectric reinforcing fibers and / or dielectric heat-conducting particles are embedded.

9. 9. The inductive charging device (1) according to claim 4, wherein the reinforcing plate (22) has at least one reinforcing body (28) made of a fiber structure, the reinforcing body (28) extending in a reinforcing body plane (29) extending parallel to the reinforcing plate plane (23) and embedded in the casting compound (26).

10. 10. The inductive charging device (1) according to any one of claims 4 to 9, characterized in that the reinforcing plate (22) has a plurality of plate openings (30) penetrating the reinforcing plate (22) in the height direction (Z), the plate openings (30) being filled with a dielectric heat-conducting material (31), the heat-conducting material (31) being in direct contact with the underside of the cover (14) and in direct or indirect contact with each of the wires (8).

11. Each of the strands (8) is in contact with and / or fixed to the lower surface (25) of the reinforcing plate at least partially via a strand holder (32); The wire holder (32) is formed so as to be in surface contact with each of the wires (8) and the lower surface (25) of the reinforcing plate, The wire holder (32) is in contact with the heat conducting material (31) in the area of ​​the plate opening (30). Inductive charging device (1) according to claim 10, characterized in that

12. The cover lower surface (14) has a three-dimensional lower surface structure (33) on its surface, The upper surface (24) of the reinforcing plate has a three-dimensional upper surface structure (34) on its surface, The lower surface structure (33) and the upper surface structure (34) are formed complementary to each other and thus form-fittingly engage with each other. Inductive charging device (1) according to any one of claims 4 to 11, characterized in that it is

13. a dielectric heat-conducting material (35) disposed between the cover (5) and the reinforcing plate (22), the heat-conducting material (35) being in contact with the cover lower surface (14) and the reinforcing plate upper surface (24); In particular, it may be specified that the dielectric heat conducting material (35) is in liquid form. Inductive charging device (1) according to any one of claims 4 to 12, characterized in that it is

14. 14. The inductive charging device (1) according to any one of claims 4 to 13, characterized in that the reinforcing plate (22) is directly attached to the cover (5) by the potting compound (26).

15. 14. The inductive charging device (1) according to claim 4, wherein the reinforcing plate (22) is manufactured separately from the cover (5) and is fixed to the cover (5) and / or the side wall (13).

16. The inductive charging device (1) according to any one of claims 4 to 13 and claim 15, characterized in that the reinforcing plate (22) is adhered to the cover (5) by a thermally conductive adhesive (37), the thermally conductive adhesive (37) being attached to the lower surface (14) of the cover and the upper surface (24) of the reinforcing plate.

17. 17. An inductive charging device (1) according to any one of claims 4 to 16, characterized in that, at least in the region of each of the coils (2), each of the wires (8) is in direct contact with the underside (25) of the reinforcing plate.

18. 18. The inductive charging device (1) according to claim 17, characterized in that the underside (25) of the reinforcing plate (22) has a wire receiving structure (38) that is shaped complementarily to each of the wires (8), and in the wire receiving structure (38), each of the wires (8) partially extends into the reinforcing plate (22) in the height direction (Z) and is in surface contact with the underside (25) of the reinforcing plate (22).

19. At least in the region of each of the coils (2), each of the wires (8) is arranged to be partially sunk in the height direction (Z) within the reinforcing plate (22), The reinforcing plate (22) is directly attached to each of the strands (8) by the casting material (26). Inductive charging device (1) according to claim 17 or 18, characterized in that

20. 17. An inductive charging device (1) according to any one of claims 4 to 16, characterized in that, at least in the region of each of the coils (2), each of the wires (8) is arranged so as to be sufficiently sunk in the height direction (Z) within the reinforcing plate (22), whereby the casting material (26) covers each of the wires (8) in a closed state in the circumferential direction (U) of each of the wires (8).

21. 21. The inductive charging device (1) according to claim 4, wherein at least one of the plurality of support elements (27) supports the reinforcing plate (22) on one of the plurality of conductive plates (6) and is arranged coaxially with the heat conducting element (17) supporting the conductive plate (6) on the bottom plate (3).

22. 22. The inductive charging device (1) according to claim 4, wherein at least one of the support elements (27) supports the reinforcing plate (22) on the bottom plate (3) and is routed between adjacent conductive plates (6) transversely to the height direction (Z).

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