TECHNICAL FIELD

The present invention relates to a solar panel. In addition, the invention relates to a method for manufacturing a solar panel.

PRIOR ART

A solar panel in the form of a flat plate solar concentrator is a type of solar panel provided with a flat transparent plate. In the prior art, this transparent plate can be provided with a fluorescent substance. Photovoltaic elements (solar cells) are attached to the side edges of the plate. The solar cells and plate are fixed to one another by means of glued connection, adhesive tape, contact lubricant or a mechanical connection. For protection, a glass plate is often attached above and below the plate. During use, sunlight falls on a surface of the transparent plate. The sunlight is guided in the transparent plate, which functions as a waveguide, to the solar cells via a process of diffusion and total internal reflection of the incident light within the plate. The fluorescent substance, if present, serves to absorb the incident light and subsequently to emit it in all directions, a portion remaining trapped in the plate as a result of total internal reflection. Mirrors can also be attached to one or more side edges and/or the underside of the plate in a similar manner as the solar cells.

A drawback of the solar concentrator according to the prior art is the fact that the construction of the system is fragile. Further steps are necessary in this regard to arrive at a usable solar panel.

It may be the case that a plurality of plates with solar cell(s) and/or mirror(s) should be attached next to one another within a solar panel. A drawback of this is the fact that mechanical stresses can be formed during the assembly of a plurality of panels. In addition, interconnection material will also have to be attached; this increases the risk of damage. A further drawback is the fact that air and/or moisture may be present between the plate and the solar cell (or between a plurality of plates); this can adversely affect durability.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a solar panel and a method for the manufacture thereof that eliminate or else reduce the aforementioned drawback of the prior art.

The object is achieved by a solar panel according to Claim 1. The invention relates to a solar panel comprising a plate-shaped body and at least one solar cell, wherein the plate-shaped body is made of a transparent material, the plate-shaped body has at least one surface for capturing incident light, the solar cell has at least at one side a light- receiving surface and the solar cell is embedded in the transparent material, the light- receiving surface of the solar cell being positioned substantially perpendicularly to the surface for capturing the incident light of the plate-shaped body.

In an advantageous manner, the invention allows the solar cells to be secured within the solar panel. As a result, the disadvantageous and fragile placing of solar cells at the edges of the plate-shaped body is dispensed with.

The invention also relates to a method for manufacturing a solar panel comprising a plate-shaped body and at least one solar cell, wherein the plate-shaped body is made of a transparent material, the plate-shaped body has at least one surface for catching incident light, the solar cell has at least at one side a light-receiving surface; including: placing the at least one solar cell in a mould; filling the mould with a liquid precursor of the transparent material, the at least one solar cell being embedded; transferring in solid form the precursor to the transparent material.

In an advantageous manner, the invention allows the waveguide to be formed and the solar cells to be attached in a single processing operation.

In one embodiment, a solar panel is provided, wherein the at least one solar cell has a light-receiving surface at a second side. Within the solar concentrator, both sides of the solar cell can in an advantageous manner be used for converting sunlight into electrical energy.

In a fiirther embodiment, the number of solar cells is greater than one, and the solar cells are mutually positioned by means of one or more spacers, the one or more spacers being embedded in the transparent material. In an advantageous manner, this allows a number of solar cells to be placed in mutual arrangement within the plate-shaped body.

In a further embodiment, the one or more solar cells are provided with electrical wire connections, the wire connections being embedded in the transparent material.

In one embodiment, the solar cells are provided with electrical connections, the connections being accommodated in the spacers embedded in the transparent material. In an advantageous manner, the need for wires between solar cells is eliminated and the coupling between solar cells is thereby simplified.

In one embodiment, a number of the solar cells are positioned with their light-receiving surface parallel to one another.

In one embodiment, an intermediate distance between solar cells positioned next to one another is equal to or greater than two times a thickness of the plate-shaped body. The concentrator principle is advantageously satisfied, the solar cell surface area being smaller than the surface area of the plate on which the light is incident.

In one embodiment, the solar panel fiirther comprises a further optical element, and the further optical element is embedded in the transparent material. The use of further optical elements advantageously increases the transmission of incident light to the at least one solar cell.

In one embodiment, the further optical element is selected from a group comprising a mirror or reflector, a grating, a light difluser and a prism. In one embodiment, the transparent material has the property that a liquid precursor is available that can change to a form which is solid and transparent to sunlight. In an advantageous manner, the transparent material allows solar cells and possibly also further optical elements to be embedded in the transparent material.

In one embodiment, the transparent material is selected from a group of materials comprising: polymethyl methacrylate, polycarbonate, polyurethane, epoxy, or sol-gel material.

In one embodiment, a fluorescent material and/or a diffusing material and/or a refractive index-increasing material is accommodated in the transparent material. The transmission of incident light from the plate-shaped body is improved in an advantageous manner.

Further embodiments according to the present invention are described in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be commented on hereinafter in greater detail with reference to a few drawings representing exemplary embodiments thereof. The drawings are intended solely to illustrate the objectives of the invention and not to restrict the inventive concept which is defined by the appended claims.

In the drawings:

Figure 1 is a schematic plan view of a solar panel in a first embodiment;

Figure 2 is a schematic side view of the solar panel;

Figure 3 is a perspective view of the solar panel;

Figure 4 is a side view of a solar panel according to the invention; and Figure 5 is a flow chart of a method according to the invention.

DESCRIPTION OF EMBODIMENTS

Figure 1 is a schematic plan view of a solar panel in the form of a solar concentrator 1 according to the invention. The solar concentrator 1 comprises a plate-shaped body 5 and a number of (at least one) solar cells 8. The plate-shaped body 5 is made of a transparent material. The solar cells 8 are embedded in the plate-shaped body 5.

In one embodiment, a light-receiving surface of each of the solar cells is positioned perpendicularly to the upper face 2 shown.

In an alternative embodiment, a light-receiving surface of one or more of the solar cells may be parallel to the upper face 2 shown. This may be advantageous if relatively more direct sunlight can in this way be caught.

The solar cells can be provided at just one surface with a light-receiving surface, but it is also possible for the solar cells to be provided at both surfaces with a light-receiving surface (what is known as a bifacial solar cell).

In one embodiment, the solar cells are mutually positioned by means of spacers 9.

Furthermore, the solar cells 8 are mutually electrically connected via wire connections (not shown), for example. Figure 2 is a cross section of the solar concentrator along the line IMI.

In one embodiment, the wire connections are part of the spacers.

Figure 2 is a schematic side view of the solar concentrator. Elements having the same reference numeral as in Figure 1 refer to identical or similar elements.

In the embodiment shown, the plate-shaped body has a thickness D which is greater than or is equal to the height of the spacers 9.

A direction L is indicated schematically for the inciding of light during use in a light- capturing surface (for example the upper face 2) of the solar concentrator. The direction of incidence L is substantially directed transversely to the plate surface 2. After incidence in the plate-shaped body 5, the incided light will, as a result of the fact that the body 5 functions as a solar concentrator, propagate substantially in the horizontal plane (i.e. perpendicularly to the direction Z) of the plate-shaped body 5. The light- receiving surface of the solar cells 8 extends substantially vertically in a direction Z, and therefore has a normal substantially perpendicular to direction Z.

Figure 3 is a perspective view of the solar concentrator. Elements having the same reference numeral as in the preceding figures refer to identical or similar elements. The solar cells 8 are positioned with the normal of the light-receiving surface perpendicular to the thickness direction Z of the plate-shaped body 5.

Figure 4 is a side view of a solar concentrator in an embodiment of the invention.

A plurality of solar cells 8 can be placed with their light-receiving surface parallel to one another in the plate-shaped body 5 in one direction.

An intermediate distance W between parallel solar cells placed next to one another is equal to or preferably greater than two times the (local) thickness D of the plate-shaped body.

It is also possible to implement an arrangement of this type in two mutually perpendicular directions so that a uniformly arranged network of solar cells is provided, that is to say in each of the two directions having a uniform intermediate distance W equal to or greater than two times the thickness D of the plate-shaped body 5. It is also possible to form a network having a triangular or hexagonal structure.

In an alternative embodiment, the normal of the surface of one or more placed solar cells may be not per se perpendicular with respect to that of the plate. The cell can also be placed at an angle. As a result, the cell can convert more direct sunlight, which propagates, after retraction, substantially parallel to the normal of the plate, into electricity. If the solar cells form an angle with respect to the plate, they will also be positioned mutually at an angle.

Figure 4 is a diagram for a method 100 for manufacturing a solar concentrator according to the invention.

The method includes a first step 101 in which the solar cells are prepared. In this step, the electrical connections between the solar cells can be formed, thus producing a network of mutually connected solar cells. During the connecting, the length of the electrical connections is selected in such a way as to allow the solar cells to be placed in a desired manner within the plate-shaped body 5 to be formed. In a following step

102, the network of solar cells is placed in a mould. The solar cells are brought with their light-receiving surface into a desired position with respect to the position of the plate-shaped body 5 to be formed. If necessary, the solar cells are also arranged at predefined positions in the mould.

Subsequently, in a step 103, the transparent material is introduced into the mould in liquid form. The solar cells are in this case embedded.

In one embodiment, a fluorescent material is dissolved in the liquid.

Alternatively or additionally, it is possible to dissolve particles, the purpose of which is to improve the optical properties of the plate to be formed, such as refractive index- increasing particles.

It will be clear to the person skilled in the art that both a vertical pouring mould and a horizontal pouring mould can be used in the pouring of the liquid transparent material.

Finally, the method includes a step 104 in which the liquid transparent material is made solid. This step can take place by carrying out one of various types of reactions including solidifying, hardening, and polymerizing, depending on the type of transparent material.

The pouring and solidifying of the transparent plate can also take place in a plurality of steps, the transparent plate being constructed during the steps. For example: A layer of precursor is firstly poured into a horizontal mould. The precursor is treated over a period of time so as to thicken/harden into a liquid having a relatively high viscosity or into a solid substance.

Subsequently, the frame of solar cells, connecting pieces and metal connections is placed on this first layer. If the layer is still in the liquid phase, the liquid should be sufficiently viscous to prevent the frame from falling to the bottom of the mould.

Subsequently, a second liquid precursor is poured onto the first transparent layer to a height such that the frame of solar cells, connecting pieces and metal connections is located fully below the surface of the precursor. Afterwards, the overall entity can harden, thus producing a transparent plate with embedded solar cells.

In an arrangement of this type, the plate-shaped body is constructed in a plurality of steps by alternately in each case further filling the mould with the liquid precursor of the transparent material and having the viscosity of the precursor increase over a period of time in the in each case further filled mould.

In this method, the number of steps of the filling of the mould with the precursor may be two or more.

The product obtained is a plate-shaped body 5 in which the solar cells are accommodated in an embedded manner. The electrical connections of the solar cells are also embedded in the body 5. In one embodiment, the electrical connections are formed by contacts and connections in the spacers 9.

The electrical connections comprise at least two electrical outputs extending to outside the plate-shaped body for providing electrical terminals in order to be able to utilize current generated during operation. In an embodiment, in step 102 of placing the solar cells in the mould, one or more mirrors are also placed in the mould, so that the one or more mirrors are embedded in the plate-shaped body 5. In addition to mirrors, other optical elements, such as a reflecting material, grating, holographic mirror, or refractive index-increasing particles, can also be embedded in the plate-shaped body 5. The embedding of the solar cells, mirrors and other optical elements advantageously provides high mechanical stability compared to a solar concentrator according to the prior art.

In the product obtained, the mirrors and other optical elements serve to direct incident light to the solar cells, allowing an improved yield to be obtained.

The transparent material has the property that a liquid precursor is available that can change to a form which is solid and transparent to sunlight.

The transparent material may consist of one selected from a group comprising: polymethyl methacrylate, polycarbonate, polyurethane, epoxy, sol-gel materials.

One or more fluorescent materials, for example an (organic) dye or quantum dots, can be accommodated in the transparent material. As a further addition or alternative addition, refractive index-increasing particles, such as metal oxide particles, can be added or a diffusing material in the form of metal or metal oxide particles, for example, such as flakes, platelets or bars, can be accommodated in the transparent material.

The plate-shaped material can assume the form of a flat plate, but it is also possible for the plate-shaped material 5 to have a curved shape.

Furthermore, a coating layer (for example silicon oxide or glass) can be attached to one or more surfaces of the plate-shaped body so as to protect the plate from external (weather) influences, such as hail, rain and ultraviolet radiation.

In one embodiment, the solar cells in the plate-shaped material are positioned with their light-receiving surface substantially perpendicular with respect to the local surface of the plate. The one or more mirrors can be positioned either with the surface normal perpendicular to the normal of the local plate surface and/or with the surface normal parallel to the normal of the local surface.

Because the solar cells and optical elements are completely encapsulated in a simple plate-shaped body, the use of glass plates to mechanically strengthen the plate may be dispensed with in the solar concentrator according to the invention. This advantageously provides a reduction in the weight of the solar concentrator with respect to the prior art. In addition, manufacturing and material costs are saved.

On account of its relatively low weight, the solar concentrator according to the invention is suitable for a number of constructional uses such as, for example, facade covering, roof covering, (semipermeable) windows and flooring tiles. Freedom of shape, as far as the plate-shaped body is concerned, also allows applications for equipment wherein solar cells (and further optical elements) are embedded in the plastics material casing of said equipment.

Alternatives and equivalent embodiments of the present invention are conceivable within the inventive idea, as will be clear to the person skilled in the art in the technical field. The inventive idea is restricted merely by the appended claims.