Shading device with a current drain system

Description

[0001] The invention relates to a shading device having a plurality of slats with photovoltaic elements for power generation and with a power discharge system.

[0002] Venetian blinds with slats mounted with photovoltaic elements (also called photovoltaic cells) are already known from the state of the art. Reference is made, for example, to documents DE 10 2007 031 236 A1 or DE 10 2014 200 359 A1.

[0003] Furthermore, it is known from the publication DE 21 2019 000 358 U1 to connect the slats with a conductor wire for current conduction. However, this conductor wire is visually unsightly and adversely affects the handling and functionality of the venetian blind.

[0004] A current conduction system with busbars extending through cutouts in the lamellas is known from the publication CN 201071671 Y. The electrical contact between the busbars is established via an electrically conductive ring, which forms the cutout and is arranged around the busbar, as well as several wires or a type of electrically conductive brush, which establish contact between the ring and the busbar.

[0005] Further prior art is provided by the publications DE 15 09 995 A, EP 3690176 A1, WO 2021 / 204358 A1, and WO 2020 / 078548 A1. It is therefore an object of the invention to provide an alternative power supply for a shading device with photovoltaic slats and a shading device therefor.

[0006] This problem is solved by the features of independent claim 1.

[0007] Advantageous developments of the invention are the subject of subordinate claims.

[0008] The inventors have recognized that there is an alternative way to transfer the electrical energy generated in the photovoltaic elements on the movable slats of a Venetian blind or Venetian blind to a power grid or power storage device and to avoid the disadvantages of the prior art.

[0009] The invention therefore describes the possibility of conducting current via an electrically conductive rod that runs through the recesses in the slats. The recesses contain electrically conductive sliding contacts that are electrically connected to the photovoltaic elements. Complex wiring of the individual slats is thus no longer necessary.

[0010] In a cable-guided venetian blind, the guide cable can be designed as an electrical conductor or busbar. Sliding contacts can be positioned on the slats around or in the two recesses or punched holes for the guide cable. One side represents the live conductor (+) and the other side the 0V conductor (-).

[0011] As an example, the current can be conducted via a copper rod, which is guided vertically through a cutout in the slats. Preferably, one copper rod is installed on each side of the venetian blind to correspond to the cable layout of the cells (positive and negative poles). The copper rod can also be installed in a split form, consisting of two half-round rods joined together with an insulator. Brass is also a suitable material for the round rod.

[0012] A current collector rubs against the round rod, establishing electrical contact. This collector can be designed in the form of a brush, a stranded wire, a bracket, or a ring. If the rod is constructed from two insulated semicircular rods, the collector will only make contact with one of the two semicircular rods at a time. Alternatively, it can be made in duplicate, but only one of these two versions is used. This concept maintains symmetry and can be beneficial for the robustness of the structure.

[0013] The grinder's mounting is best made flexible, allowing for rotations and vertical and horizontal shifts of the blades. A ring can be attached to the recess using four elastic threads, each positioned at 90° intervals.

[0014] In the following, a variant with two busbars designed as semicircular bars and a sliding contact with two sliding pads is described.

[0015] An electrical insulator is located between the two semicircular rods. The semicircular rods can each be glued to one side of the insulator, with the insulator either flush with the edges of the semicircular rods or slightly protruding. This design ensures galvanic insulation between the two semicircular rods.

[0016] The semicircular rods are secured above and below the curtain. This is achieved using brackets that can either be made of a non-conductive material or with an insulating insert that also ensures galvanic isolation of the semicircular rods. The insert can extend slightly beyond the bracket, ensuring insulation even if a layer of water forms on the bracket.

[0017] The power supply to a consumer, for example an inverter, a power storage device or similar, can be achieved primarily via the upper bracket, for example by fixing and contacting cables by soldering.

[0018] The sliding contact comprises a sleeve-like, ring-shaped wiper body, lateral guide or fixing pins, at least one abrasive pad, at least one contact spring, and a retaining clip. The contact springs and the abrasive pads are inserted into the wiper body.

[0019] The guide pins of the grinder body can be clipped into the retaining clips attached to the blade. This design allows for the blade to pivot and lateral displacement. Each grinding pad can be soldered to a cable connected to the photovoltaic elements.

[0020] Different photovoltaic elements can be used on the slats. The various photovoltaic slat concepts can be divided according to the different technologies of the photovoltaic elements used. First-generation photovoltaic elements (wafer-based photovoltaic elements) and second-generation photovoltaic elements are characterized by the fact that they do not exceed the Shockley-Queisser (SQ) limit for single-band-section devices. Third-generation photovoltaic elements, on the other hand, have an efficiency potential above the SQ limit. The SQ limit describes the maximum achievable conversion efficiency of solar energy for a specific material. The limit is the benchmark against which new photovoltaic technologies are compared. A specific material has a specific band gap, which is responsible for the fact that only certain spectra of light can be absorbed.The remaining spectra cannot be absorbed and therefore cannot be used to convert them into electrical current (first- and second-generation photovoltaic elements). Third-generation photovoltaic elements, for example, circumvent this fact by using so-called tandem photovoltaic elements, in which several materials are used in different layers to also absorb the remaining spectra of light and convert them into electrical current.

[0021] Conventional first-generation photovoltaic elements: First-generation photovoltaic elements, i.e., wafer-based photovoltaic elements, are used here. This technology is advantageous because, thanks to many years of research and its large market share, it offers a particularly high degree of long-term testing, a very good price-performance ratio, and very high efficiency. A major disadvantage, however, is that mass-produced photovoltaic modules using this technology are only available in sizes that cannot be applied to the slats. Therefore, slats equipped with conventional photovoltaic elements must be manufactured in such a way that the photovoltaic elements are interconnected and laminated onto the raw slats themselves to form a module. Since individual standard photovoltaic elements are too large for the slats, they must be cut through.

[0022] Second- and third-generation photovoltaic elements: These photovoltaic elements have the advantage that, partly due to different manufacturing processes, they can be manufactured in almost any size with significantly fewer modifications to the production process. This allows the existing surface of the slats to be used more efficiently and without any gaps. A crucial disadvantage, however, is that second- and third-generation photovoltaic elements, based on the current state of the art, often cannot yet compete with first-generation photovoltaic elements in terms of efficiency. Some manufacturing processes allow the thin-film photovoltaic cell layer to be vapor-deposited directly onto the slats, which then act as a substrate. For this purpose, it may be beneficial to coat the slats in advance so that they have more suitable properties for their role as a substrate.The techniques used during the manufacturing process include thermal evaporation, sputter deposition, laser deposition and metal-organic vapor phase epitaxy.

[0023] Adhesive second- and third-generation photovoltaic elements: These also use second- and third-generation photovoltaic elements, but instead of being manufactured on the slats themselves, they are instead manufactured on a film and then glued onto the slats. This concept offers the crucial advantage of allowing for a spatial separation between the production of the slats and the production of the photovoltaic elements. The photovoltaic film can be manufactured by the meter and stored in the correct width and cut to size.

[0024] In addition, different slats can also be used. The use of slats that are less curved in the application area of ​​the photovoltaic elements, such as flat slats, can have positive effects. Firstly, the photovoltaic elements only have to adapt to a less pronounced bend, which simplifies the production process and reduces the demands on the photovoltaic elements themselves. Secondly, the photovoltaic elements can be more easily protected from external influences. It is crucial that the encapsulation of the photovoltaic cell layer adheres sufficiently strongly and reliably to the edges of the slats so that it can exert its encapsulating effect. Since expansion or contraction of the slats can lead to detachment at weak points, such as the edges, it is advisable to take special precautions here.For example, the encapsulation can be folded over one or more outer edges of the slats, allowing the film to adhere to the underside of the slat. Since the flat slat has no outer edges, folding over the film is possible without any problems. With a slat with a folded edge, the film would not be easy to fold over and laminate, and the package height would increase further, as the film would extend over the edge, thus further thickening the thickest part of the slat. The film can then be particularly firmly secured to the underside using other possible methods, such as gluing.

[0025] Accordingly, the inventors propose to improve a shading device, in particular a Venetian blind or Venetian blind, having a plurality of slats with photovoltaic elements for power generation and having a power conduction system, with at least two busbars which run through recesses in the slats and electrically connect them to one another in order to conduct the power generated in the photovoltaic elements, wherein sliding contacts are arranged in the recesses of the slats, which are electrically connected to the photovoltaic elements and which establish an electrical connection of the photovoltaic elements (7a) to the busbars, wherein the sliding contacts are each designed as a sleeve-like, annular sliding body which encloses the respective busbar(s) and in which at least one sliding coating is present which is electrically connected to the photovoltaic elements of the slat,that the grinder body is mounted on the respective lamella so that it can move in the longitudinal direction of the lamella.

[0026] The power collection system serves to feed the electricity generated in the photovoltaic elements of the slats into a power grid or a power storage unit. Depending on the design of the power collection system, an inverter is advantageously also provided. The shading device is preferably a Venetian blind or a Venetian blind, in particular a Venetian blind canopy. The invention is described below using a shading device designed as a Venetian blind.

[0027] As with conventional venetian blinds, the slats of the external venetian blind are movably mounted in lateral guide rails by means of guide pins attached to the short longitudinal ends. When the slats are raised and lowered or tilted, the guide pins move in the guide rails. Furthermore, the shading device, in particular the external venetian blind, has at least one tension element for moving the slats. Advantageously, two tension elements in the form of pull cables, cords, or straps are provided, which are preferably arranged near the two longitudinal ends of the slats. Using the tension straps, the slats can be moved up and down as well as tilted around their longitudinal axis.

[0028] The current discharge via busbars running through the slats can of course be combined with other ways of discharging the current generated in the photovoltaic elements, for example by means of busbars in the guide rails.

[0029] In a particularly simple design, exactly two busbars run through each slat, which are electrically connected to the photovoltaic elements. However, more busbars can also run through the slats, although not every slat has an electrical connection. This allows different types of series connection of the slats to increase the voltage. For example, a busbar is electrically connected alternately to the slats, or the slats are insulated from the busbar. According to the invention, however, the busbars run through all slats, even if there is not electrical contact with every slat. In an embodiment with only two busbars, these are advantageously at the same potential.

[0030] The busbars are preferably stationary. To allow the busbars to pass through the laminations, the laminations each have cutouts, openings, or holes through which the busbars are guided. The cutouts are preferably located near the longitudinal ends of the laminations. The cutouts can either provide electrical contacts to the busbars or be insulated from the busbars to prevent electrical contact.

[0031] A simple embodiment provides that the lamellae each have two recesses through which a busbar runs, whereby the two busbars are at different potentials.

[0032] In principle, it is also possible for more than one busbar to run through a recess, with the individual busbars being contacted differently and, for example, also being at different potentials. Another embodiment therefore provides for two busbars to run through a recess, each at a different potential. In this case, for example, there can be an electrical connection to one busbar, while the other busbar is electrically insulated in this section.

[0033] In a particularly preferred embodiment, the busbars are designed as elongated rods or bars. The rods are preferably round, but can also be square. A further embodiment provides for the busbars to be designed as rods with half a cross-section. Such rods or busbars are referred to below as half-rods. A half-rod is preferably semi-circular or square with only half the cross-section compared to a simple rod. Two semi-circular half-rods are preferably formed, the flat sides of which are oriented towards one another, resulting in a two-part round rod. The half-rods can either be at the same potential or at two different potentials. If the half-rods are at different potentials, an insulator is advantageously arranged between the two halves or half-rods.The half-rods, for example, are glued flat to the insulator.

[0034] The busbars are generally made of a material with the best possible conductivity. A preferred embodiment is a metal or alloy, such as copper, brass, or aluminum.

[0035] To dissipate the current generated in the photovoltaic elements, sliding contacts are arranged in the recesses of the slats and are electrically connected to the photovoltaic elements. The sliding contacts move with the slats along the busbar(s) as they are pulled up and down. The electrical contact between the movable slats or sliding contacts and the stationary busbar(s) is advantageously maintained when the slats are tilted or rotated.

[0036] In an embodiment with only one busbar in a recess, the busbars are advantageously contacted from at least two opposite sides. This enables better and more reliable contact with even pressure from two opposite sides. It is also advantageous if the sliding contacts are spring-loaded.

[0037] The embodiment of a sliding contact according to the invention provides for a sleeve-like, annular wiper body which encloses the busbars and in which at least one sliding coating is present, which is electrically connected to the photovoltaic elements of the lamella. The wiper body is advantageously designed to be electrically insulating. There can be one sliding coating per wiper body if there is a busbar in the recess. Or there can be two sliding coatings per wiper body if two busbars are guided through the recess, each of which is at a different potential and is therefore contacted separately by the sliding coatings. The sliding coatings can be soldered to the photovoltaic elements, for example by means of cables. In addition, springs can be provided in the wiper body, which press the sliding coatings against the busbars.

[0038] The sleeve-like wiper body is movably mounted. According to the invention, the wiper body is movably mounted in the longitudinal direction of the lamella. The movable mounting advantageously compensates for or enables lateral movements of the lamellas, temperature-related length changes, and pivoting movements of the lamellas around their longitudinal axis. For example, the wiper body has guide pins aligned along the lamella's longitudinal axis, which are pivotably mounted in clip-like holders attached to the lamellas.

[0039] Alternative designs for the sliding contacts are also possible. For example, the sliding contacts can also be designed as a brush, stranded wire, bracket, or ring.

[0040] Depending on the number of busbars and their interconnection, not every busbar is electrically connected in a recess. Therefore, an electrically insulating insert can be formed in the recesses so that the respective lamella has no contact with a busbar, or only with a specific busbar among several busbars.

[0041] The different design of the recesses, with or without sliding contact, or with or without insulation, makes it possible to implement more than two busbars or busbars that are at the same potential. Furthermore, the laminations can be connected to the busbars in various series circuits; for example, two or three laminations can be connected in series.

[0042] For power distribution, the busbars are connected to a power grid or a power storage unit. The busbars are advantageously fixed at their ends in brackets, with one of the brackets serving as the power distribution point. Wiring is preferably attached to an upper bracket. The lower bracket is advantageously insulated, particularly water-resistant.

[0043] Furthermore, the power conduction system is advantageously protected from weather influences such as rain, sunlight, etc. in order to ensure the longest possible service life with minimal wear.

[0044] One embodiment of the current conduction system therefore provides for rubber seals and / or brush seals to be inserted into at least some of the longitudinal openings of the guide rails. These seals do not completely close the longitudinal opening, but allow the guide pins to slide up and down through the seals.

[0045] The advantages of brush seals, for example made of nylon or Perlon, are: Easy implementation thanks to prefabricated strips that can be applied along the longitudinal openings; brush seals are weather- and water-resistant; the replacement of slats is not affected; and protection in all slat positions.

[0046] However, individual bristles can become loose and contaminate the busbars. Furthermore, a brush seal does not provide complete protection against the ingress of moisture and dust.

[0047] The advantages of rubber seals, for example made of silicone rubber, are: Protection against splash water and dirt; easy installation; does not affect the replacement of slats; protection in all slat positions.

[0048] However, the material of the rubber seals must meet stringent requirements, as they must be permanently elastic and not become brittle. The friction between the guide pins and the seal is significantly greater with a rubber seal than with a brush seal.

[0049] Another embodiment of the current conduction system provides for a fabric insert to be arranged between the guide pins of adjacent slats. This insert is stretched when the slats are lowered and at least partially covers the openings of the guide rails. The fabric used is advantageously as flexible as possible, weather-resistant and breathable, as well as waterproof and UV-resistant.

[0050] The advantages of fabric inserts are: The longitudinal openings are covered to make them dust- and watertight; installation is possible with moderate effort; and any moisture that penetrates can evaporate.

[0051] However, a fabric insert only protects the longitudinal opening when the slats are lowered. Depending on the material, the individual fabric sections can fray at the sides. Replacing individual slats is made more difficult by the fabric inserts attached to the slats.

[0052] In an advantageous embodiment of the shading device according to the invention with a plurality of slats with photovoltaic elements, it is proposed that at least two slats are electrically connected to one another in series to form a slat set, wherein the connection points between the two slats of a slat set are electrically coupled to one another in parallel via a respective busbar.

[0053] If several sets of slats are used in the shading device, each consisting of two slats connected in series, this can be achieved by having exactly two slats connected in series per set of slats, whereby: The potential-equal connection points between the first slat and the second slat of a slat set are electrically connected via a busbar on a first side of the shading device, and each slat set is electrically connected to a positive and a negative busbar on the second side of the shading device opposite the first side. This results in the slats being arranged alternating in polarity from top to bottom.

[0054] If several sets of slats are used in the shading device, each consisting of three slats connected in series, this can be achieved by designing a current discharge system in such a way that each set of slats has exactly three slats connected in series, whereby: the potential-equal connection points between the respective first slats and the second slats are electrically connected via a first busbar on a first side of the shading device, the potential-equal connection points between the respective second slats and the third slats are electrically connected via a second busbar on a second side of the shading device opposite the first side, and each set of slats is electrically connected to a positive busbar and a negative busbar on one side of the shading device.

[0055] The invention also relates to a shading device, in particular a Venetian blind or a Venetian blind, at least comprising a curtain with a plurality of slats with photovoltaic elements for generating electricity, wherein a power discharge system as described above is provided for discharging the generated electricity.

[0056] The shading device is preferably a Venetian blind or a Venetian blind, in particular a Venetian blind canopy. The invention is further described with reference to a shading device designed as a Venetian blind.

[0057] The structure of the Venetian blind is similar to that of a conventional Venetian blind. Photovoltaic elements for electricity generation are mounted on the slats, either as a complete coating of the slats or as individual sections of the slats. Both conventional first-generation photovoltaic elements and second- or third-generation photovoltaic elements can be used.

[0058] One embodiment of the shading device, in particular a Venetian blind, provides that the blind comprises at least a first slat pack and a second slat pack, wherein the slat packs are tilted differently around the respective longitudinal axes of the slats. This type of blind is generally referred to as a two-part blind. Preferably, an upper slat pack is rotatable or tiltable separately from the remaining slats. For example, a lower section of the blind can be completely closed to generate electricity, while an upper section remains open or at least partially open to allow daylight to enter a room.

[0059] In the following, the invention is described in more detail using the preferred embodiments with the aid of the figures, wherein only the features necessary for understanding the invention are shown.

[0060] They show in detail: FIG 1: a schematic perspective view of a longitudinal end of a lamella with a current conduction system FIG 2: a schematic perspective view of the sliding contact according to the Figure 1 , FIG 3: a schematic cross-sectional view through the sliding contact according to the Figure 2 with two busbars, FIG 4: a schematic exploded view of the sliding contact according to the Figure 2 without wiper body, FIG 5: a schematic perspective view of two busbars with holders at the ends, FIG 6: a schematic representation of a Venetian blind with current conduction system and a first series connection of the slats, FIG 7: schematically simplified representation of the electrical series connection of the Venetian blind according to Figure 6 FIG 8: a schematic representation of a Venetian blind with power conduction system and a further series connection of the slats, and FIG 9: schematically simplified representation of the electrical series connection of the Venetian blind according to the Figure 8 .

[0061] In the Figure 1A schematic perspective view of a longitudinal end of a slat 7 with a power conduction system is shown. The slat 7 is part of a shading device designed as a Venetian blind. For clarity, the guide pin at the longitudinal end of the slat and the other components of the Venetian blind are not shown. The photovoltaic element arranged on the slat 7, which generates the electricity, is also not shown here. In the region of the longitudinal end, the slat 7 has a recess through which the busbars are guided. In this exemplary embodiment, there are two busbars designed as semicircular half-bars 4a, 4b, with each half-bar 4a or 4b being at a different potential. An insulator is arranged between the two half-bars 4a, 4b. The power conduction system also comprises a sliding contact 10, which is arranged around the two half-bars 4a, 4b in the recess 2.The sliding contact 10 encloses the two half-rods 4a, 4b and establishes a separate electrical connection of the photovoltaic element to the half-rods 4a, 4b.

[0062] In the Figure 2 is a schematic perspective view of the sliding contact 10 according to the Figure 1 The sliding contact 10 comprises a central, sleeve-like sliding contact body 11, which has an opening through which the two half-rods 4a, 4b extend. The sliding contact body 11 is made of an electrically insulating material. Two flat sliding pads 14 are arranged in the opening of the sliding contact body 11, with each sliding pad 14 contacting a half-rod 4a, 4b. The sliding pads 14 are spring-loaded. Furthermore, the sliding pads 14 are electrically connected to the electrical connection 6 to the photovoltaic elements via conductor pins 15.

[0063] The grinder body 11 has two oppositely positioned guide pins 12 on its outer side, which are movably mounted in clip holders 13. The guide pins 12 run in the longitudinal direction of the slat 7 and can be moved in this direction within the clip holders 13. A thickening is provided at the free ends of the guide pins 12 so that they cannot be pushed out of the clip holders 13. The clip holders 13 are attached to the slat 7, for example, by adhesive.

[0064] In the Figure 3 is a schematic cross-sectional view through the sliding contact 10 according to the Figure 2with two semicircular busbars. The busbars are designed as half-bars 4a, 4b with a semicircular cross-section. An insulator is glued between the half-bars 4a, 4b. The half-bars 4a, 4b can thus be at different potentials. Each half-bar 4a, 4b is contacted by a sliding coating 14, which creates an electrical connection to the photovoltaic elements via a conductor pin 15.

[0065] In the Figure 4 is a schematic exploded view of the sliding contact 20 according to the Figure 2 Shown without the wiper body 11. The springs 16, which press the sliding pads 14 in the opening of the wiper body 11 against the half-rods 4a, 4b, are visible. Also visible are the conductor pins 15, which protrude from the sliding pads 14 through the wiper body 11.

[0066] In the Figure 5A schematic perspective view of two busbars designed as half-bars 4a, 4b with holders 20 at the ends is shown. The holders 20 are each designed as two half-shells 21, 22 that enclose the ends of the half-bars 4a, 4b. The upper holder 20 is open at the top, so that a cable is connected to each end of the two half-bars 4a, 4b to conduct the generated current. The lower holder 20 completely encloses the ends of the half-bars 4a, 4b, insulating and protecting them.

[0067] The Figure 6shows an embodiment of the upper part of a Venetian blind with a slat box 8 and a curtain, the slats 7.1 and 7.2 of which are provided with photovoltaic elements, which are connected in series in sets to one another and each form a slat set 7. Here, photovoltaic elements of the slats are connected in sets to the busbars 4+ and 4- for current discharge, whereby a connection of the photovoltaic elements to the busbar 4.z is established for each set in such a way that a total of one serial connection is created between the photovoltaic elements of the two slats 7.1 and 7.2 for each slat set 7, and thus the voltages U1 and U2 generated by the photovoltaic elements are added to a total voltage Uges and, ideally, doubled. As can be seen from the Figure 6As can be seen, the busbar for the intermediate potential 4z runs on one side in one guide rail 1, while the two current discharge rails 4+ and 4- run in the right guide rail 1.

[0068] For a clearer illustration, the schematic electrical circuit of the photovoltaic elements mounted on the slats 7.1 and 7.1 is shown in the Figure 6 again in the Figure 7shown. On the left is the negative or earthed busbar 4-, from which leads lead to the first slat 7.1 of a slat set 7. The first and second slats 7.1 and 7.2 are connected together with reversed polarity to the busbar 4.z, where a common intermediate potential of the voltage U1 is present between the first and second slats 7.1 and 7.2. The second slats 7.2 are then connected with the positive side of their photovoltaic elements with their voltage U2 to the busbar 4+, whereby a total voltage Uges = U1 + U2 is generated between the busbars 4- and 4+. The two busbars 4+ and 4- serve to discharge current with the potential of the total voltage Uges and combine the entire current output of the venetian blind according to the invention.

[0069] The Venetian blind therefore consists of a plurality of slat sets 7 connected in parallel, comprising serially connected slats 7.1 and 7.2, whereby the intermediate potential between all first slats 7.1 and all second slats 7.2 is interconnected.

[0070] Another embodiment of the Venetian blind provides that three slats 7.1, 7.2 and 7.3 of a slat set 7 are connected in series and the slat sets 7 of the entire Venetian blind are connected in parallel and the first, second and third slats 7.1, 7.2 and 7.3 are connected in parallel. Such an embodiment is exemplified in the Figure 8This shows the upper part of a Venetian blind with a slat box 8 with laterally arranged guide rails 1 and three slat sets 7. Each slat set 7 contains a first, second and third slat 7.1, 7.2 and 7.3, each with a photovoltaic element arranged on it. A busbar 4+ and 4- is arranged on the right and left in the guide rails, which on the one hand is connected to an external power connection and on the other hand electrically connects the slat sets 7. In addition, a busbar 4.z is arranged in each of the lateral guide rails 1, which connects the individual slats 7.1 with 7.2 and 7.2 with 7.3 in series and at the same time connects all first slats 7.1, all second slats 7.2 and all third slats 7.3 in parallel.

[0071] A schematic representation of this electrical circuit from the Figure 8 is in the Figure 9shown. There are four slat sets 7, each consisting of the three slats 7.1 to 7.3. These three slats 7.1, 7.2 and 7.3 are connected in series to each other within each slat set 7. At the same time, the slat sets are each connected in parallel via busbars 4- and 4+. In addition, there is also a parallel connection to the same intermediate potentials of the individual slats 7.1 and 7.2 via the two busbars 4.z, whereby these busbars 4.z are each insulated from the outside. In this way, the achieved operating voltage Utotal can be increased to the sum of the individual voltages U1+U2+U3 of the first, second and third slats 7.1, 7.2 and 7.3 in order to keep transmission losses as low as possible. At the same time, the current output of the slat sets 7 is summed up according to their number in the venetian blind. List of reference symbols

[0072] 1Guide rail 2Recess 4Busbar / rod 4+positive busbar 4-negative busbar 4.zBusbar for intermediate potential 5Insulator 6Connection between sliding contact and photovoltaic element 7Slats with photovoltaic elements 7.1First slat with photovoltaic element of a serial slat set 7.2Second slat with photovoltaic element of a serial slat set 7.3Third slat with photovoltaic element of a serial slat set 8Slat box 9+positive busbar 9-negative busbar 10Sliding contact 11Slider body 12Guide pin 13Clip holder 14Sliding pad 15Conductor pin 16Spring 20Holder 21First half-shell 22Second half-shell 23Cable

Claims

1. Shading device, in particular a Venetian blind or slatted blind, having a plurality of slats (7) with photovoltaic elements for power generation, and having a current discharge system with at least two busbars (4a, 4b, 4+, 4-, 4.z) which run through recesses (2) in the slats (7) and connect them to one another in an electrically conductive manner, in order to conduct the electricity generated in the photovoltaic elements, wherein sliding contacts are arranged in the recesses (2) of the slats (7), said sliding contacts being connected to the photovoltaic elements (7a) in an electrically conductive manner and establishing an electrical connection of the photovoltaic elements (7a) to the busbars (4a, 4b, 4+, 4-, 4.z), wherein the sliding contacts are each designed as a cuff-like, annular sliding body (11) which surrounds the respective busbar(s) and in which at least one sliding coating (14) is present, which is electrically connected to the photovoltaic elements of the slat (7), characterized in that the sliding body (11) is movably mounted on the respective slat (7) in the longitudinal direction of the slat (7).

2. Shading device according to the preceding Claim 1, characterized in that exactly two busbars (4) run through each slat (7) and are electrically connected to the photovoltaic elements.

3. Shading device according to any one of the preceding claims, characterized in that the slats (7) each have two recesses (2), through each of which a busbar (4) runs, wherein the two busbars (4) are at different potentials.

4. Shading device according to any one of the preceding claims, characterized in that two busbars (4) run through a recess (2), each busbar being at a different potential.

5. Shading device according to any one of the preceding claims, characterized in that the sliding contacts (10) are spring-mounted.

6. Shading device according to any one of the preceding claims, characterized in that an electrically insulating insert is formed in the recesses (2).

7. Shading device according to any one of the preceding claims, characterized in that the busbars (4) are fixed at their ends in holders (20), wherein the current discharge takes place at one of the holders (20) .

8. Shading device according to any one of the preceding claims, characterized in that multiple sets of at least two slats (7.1, 7.2, 7.3) are electrically connected in series to form a set of slats (7) in each case, wherein the connection points (9) between the slats (7.1 with 7.2 and 7.2 with 7.3) are electrically coupled in parallel to one another via a respective busbar (4.z).

9. Shading device according to the preceding Claim 8, characterized in that each set of slats (7) comprises exactly two serially connected slats (7.1, 7.2), wherein: - the equipotential connection points (9) between the first slat (7.1) and the second slat (7.2) are electrically connected via a busbar (4.z) on a first side of the shading device, and - each set of slats (7) is electrically connected to the positive and negative busbars (4+, 4-) on the second side of the shading device opposite the first side, wherein the polarity (+, -) of the slats in the shading device alternates from top to bottom.

10. Shading device according to the preceding Claim 8, characterized in that each set of slats (7) comprises exactly three serially connected slats (7.1, 7.2, 7.3), wherein: - the equipotential connection points (9) between the first slat (7.1) and the second slat (7.2) are electrically connected via a first busbar (4.z) on a first side of the shading device, - the equipotential connection points (9) between the second slat (7.2) and the third slat (7.3) are electrically connected via a second busbar (4.z) on a second side opposite the first side of the shading device, - each set of slats (7) is electrically connected to a positive busbar (4+) and a negative busbar (4-) on each side of the shading device.

11. Shading device according to any one of the preceding claims, wherein the slats (7) form a cover, characterized in that the cover comprises at least a first package of slats and a second package of slats, wherein the packages of slats are tilted differently about the respective longitudinal axes of the slats.