solar panel

Abstract

The invention relates to a solar module comprising - a front element (1) and a rear element (5), - a front embedding material (2) that abuts the front side element (1), - a rear embedding material (4) that abuts the rear element (5), - a plurality of electrically interconnected solar cells (3) arranged between the front embedding material (2) and the rear embedding material (4) and encapsulated in a weatherproof manner in an encapsulation volume by means of the front element (1), the rear element (5) and the front embedding material (2) and rear embedding material (4) surrounding the solar cells (3), - wherein an additional layer (8) is formed between the rear embedding material (4) and the back side element (5), which reflects wavelengths of 800 nm or longer wavelengths and - wherein the rear embedding material (4) comprises an additive (6) and / or the additive layer (8) comprises an additive (6) on its side facing the rear embedding material (4), wherein the additive (6) is transparent at wavelengths of 800 nm or longer and is configured to absorb at wavelengths below 800 nm and wherein there is sufficient additive (6) to cause areas of the solar module laminate to appear dark to the human eye in sunlight.

Description

[0001] The invention relates to a solar module. In particular, the invention relates to a solar module comprising a front element, a rear element, a front encapsulating material adjacent to the front element, a rear encapsulating material adjacent to the rear element, and a plurality of electrically interconnected solar cells arranged between the front encapsulating material and the rear encapsulating material. The solar cells are weather-resistantly encapsulated in an encapsulation volume by means of the front element, the rear element, and the front encapsulating material and rear encapsulating material enclosing the solar cells in the form of a laminate.

[0002] The front element is arranged on a light-incident side of the solar module, and the back element is arranged on a solar module back opposite the light-incident side. The front element and the front encapsulant each comprise materials that are transparent to the spectrum of sunlight that can be converted into electrical energy by the solar cells, i.e., have a transmittance of over 80%. Therefore, the appearance and / or color of a solar module seen during use and / or operation is largely determined by the color of the solar cells, the back encapsulant, and the back element of the solar module. Solar cells have a dark appearance because they absorb the visible light spectrum across a broad band. Therefore, the cells themselves typically have a dark blue or black color appearance.To provide the entire solar module with an aesthetically consistent appearance, it is desirable for the areas between the electrically interconnected solar cells to appear darker to the human eye than the solar cells themselves. There are several ways to produce such a solar module with a uniform, dark color appearance.

[0003] By applying a black-colored backside grid to the inside or outside of the backside element in the area between the interconnected solar cells, or by using a fully optically black rear embedding material, the overall appearance can take on the desired uniform, dark, black color. The dark color can be achieved using pigments such as carbon black or similarly broadband absorbing pigments. When carbon black is used, sunlight, including its infrared component, is almost completely absorbed. However, this has a negative impact on the performance of the solar module, particularly due to the associated heating of the solar module.

[0004] A solar module that appears completely black to the human eye according to the state of the art is Fig. 1. It has a front side element 1 and a rear side element 5, each of which is plate-shaped. The front embedding material 2 lies against the front side element 1, and the rear embedding material 4 lies against the rear side element 5. The front embedding material 2 is optically transparent. The rear embedding material 4 has an additive 6, such as carbon black, which gives it a black appearance. The plurality of electrically interconnected solar cells 3 are arranged between the front embedding material 2 and the rear embedding material 4 and are encapsulated in a weather-resistant laminate in an encapsulation volume by means of the front side element 1, the rear side element 5 and the front embedding material 2 and rear embedding material 4 enclosing the solar cells 3.Due to the black color appearance of the rear embedding material 4 and the dark color appearance of the solar cells 3, the solar module has a consistently black color appearance to the human eye when viewed from above onto the front element 1 and thus an aesthetically pleasing uniform appearance.

[0005] A variant of this solar module is in Fig. 2. The Fig. The solar module shown in 2 corresponds to the one in Fig. 1, with the difference that the rear embedding material 4 is optically transparent and contains no additive, and that a rear-side grid 7 is arranged between the rear embedding material 4 and the rear-side element. This grid contains an additive 6 that imparts the desired dark color appearance in the areas between the electrically interconnected solar cells 3. This solar module also has a black color appearance when viewed from above onto the front-side element 1.

[0006] It is an object of the invention to provide a solar module with an aesthetic appearance that is sufficiently uniform to the human eye and has an increased power output.

[0007] This object is achieved by a solar module having the features of claim 1. Advantageous further developments and modifications are specified in the subclaims.

[0008] According to the invention, an additional layer is formed between the rear embedding material and the rear side element, which additional layer reflects light with wavelengths of 800 nm or longer wavelengths, and the rear embedding material comprises an additive and / or the additional layer comprises an additive on its side facing the rear embedding material, wherein the additive is transparent to light with wavelengths of 800 nm or longer infrared wavelengths and is designed to absorb light with wavelengths below 800 nm, and wherein sufficient additive is present that regions of the solar module laminate provided with the additive appear dark to the human eye in sunlight. As a result, the additional layer reflects infrared light that was not previously absorbed by the additive.By largely absorbing the visible spectral range, a color that appears black to the human eye is combined with a high degree of reflection of infrared radiation outside the visible wavelength range. This increases the efficiency of the solar module while maintaining the same aesthetic appearance.

[0009] The invention is therefore based on a combination of a material that acts as an absorber only for visible light wavelengths up to 800 nm, with a broadband reflective material arranged behind it. When light hits the front of the solar module, the visible spectral range of the light is absorbed by the additive, so that not only the solar cells but also the intercellular spaces exhibit the desired dark color appearance, while infrared radiation above 800 nm is not absorbed by the additive and is reflected back. Through multiple reflections, the infrared radiation, particularly when incident at an angle, can thus contribute to an increase in the electrical energy yield of the solar module. The properties of the additive are thus used both to color the overall appearance of the solar module and to selectively transmit infrared radiation, which is reflected back by the additional layer.The infrared light transmitted through the additive is thus reflected back towards the solar cells.

[0010] The term "black color appearance" is intended to describe a dark color that, in addition to black, also includes dark blue, dark green, or dark red. If the additive appears black to the human eye, the solar module presents a uniform black appearance to the human eye when viewed from the front, so that the solar cells of the solar module are no longer distinguishable from the spaces between them and the electrical interconnections to the human eye, at least at distances of several meters or more.

[0011] There are some color systems, such as Pantone, HSK, and RAL, that define each color according to a classification. Materials, at least in areas where the additive is integrated, preferably have a color that corresponds to RAL 5004, RAL 7016, RAL 7021, RAL 8002, RAL 9004, RAL 9005, RAL 9011, or RAL 9017 according to the RAL classification of the RAL German Institute for Quality Assurance and Labeling (Bonn, Germany).

[0012] In a preferred embodiment, the additional layer contains a white dye. This achieves the desired broadband reflection.

[0013] The additional layer can be arranged over the entire surface in or on the rear element. The additional layer is preferably segmented. To achieve the performance improvement of the solar module, it is sufficient for the additional layer to be arranged at least between the solar cells, i.e., in the intercellular spaces, when viewed from above. The additional layer is preferably arranged in a grid-like or strip-like manner in or on the rear element, so that the additional layer is arranged in regions that, when viewed from above, are arranged between the solar cells, i.e., in the intercellular spaces.

[0014] The phrase "when viewed from above, the solar module is arranged at least between the solar cells, i.e., in the intercellular spaces," means that either the front or back side is viewed, and all materials except the solar cells and the additional layer are considered optically transparent, although this need not be the case in reality. The front-side element and the front embedding material are optically transparent, while the rear embedding material and the rear element can be independently transparent or colored, i.e., at least partially absorbent.

[0015] In a preferred embodiment, the additive is added to the rear embedding material in such a way that the rear embedding material has a black color appearance in the visible spectral range over its entire surface. This ensures that, when viewed from above, the front of the solar module appears black to the human eye.

[0016] Alternatively, the additive is preferably arranged in areas of the rear embedding material or in areas of the additional layer that are located between the solar cells in a plan view of the solar module. To achieve increased electrical power output and aesthetic appearance, it is sufficient for the intercellular spaces to contain the additive.

[0017] Preferably, the backing element is printed, laminated, and / or coated with the additional layer. In a preferred embodiment, the additional layer is printed, laminated, and / or coated with the additive if the additive is not integrated into the backing embedding material. This ensures that the additive and the additional layer interact and are fixed in a defined spatial position relative to one another.

[0018] The additive is preferably selected from the group consisting of molecular dyes and pigments. More preferably, the additive is at least one pigment, more preferably at least one absorbing pigment. Metallic and non-metallic color pigment mixtures that are absorbing in the visible light wavelength range are preferably used. In contrast, the color pigments used exhibit high transparency in the infrared wavelength range.

[0019] The additional layer preferably contains a white pigment, preferably TiO2. TiO2 is inexpensive and compatible with many materials.

[0020] In a preferred embodiment, the solar module is designed as a bifacial solar module. This allows the light transmitted by the additional layer to act on both sides of the cell.

[0021] The majority of solar cells preferably comprise tandem solar cells or TopCon (Tunnel Oxide Passivated Contact) solar cells or bifacial solar cells. Tandem solar cells combine solar cells made from multiple material systems, each with optimal band gaps for individual spectral ranges, thus maximizing the conversion of incident radiation. This enables higher efficiency to be achieved. TopCon solar cells also exhibit comparatively high efficiency and low degradation over their lifetime. In bifacial solar cells, a full-surface rear electrode is generally replaced by a grid, e.g., an aluminum grid. This grid is highly transparent, allowing indirect light from the rear of the solar cell to be absorbed. Indirect light can therefore be absorbed by both sides of the solar cell.

[0022] In a preferred embodiment, the front element and the rear element are each formed as a thin glass pane. The front encapsulating material and the rear encapsulating material can each be formed as an EVA (ethylene vinyl acetate) layer, an EPE (expanded polyethylene film, e.g., EVA-PE (polyethylene)-EVA extruded film), a POE (polyolefin elastomer) layer, e.g., cross-linked PE (polyethylene) or modified PE (polyethylene), or a TPO (thermoplastic polyolefin) layer, e.g., non-cross-linked PE (polyethylene) or modified PE (polyethylene).

[0023] The invention is explained in more detail with reference to the following description of two preferred embodiments. The figures are purely schematic and not drawn to scale.

[0024] It shows: Fig. 1 a cross-sectional view of a solar module according to the prior art; Fig. 2 a cross-sectional view of another solar module according to the prior art; Fig. 3 a cross-sectional view of a solar module according to a first embodiment; and Fig. 4 a cross-sectional view of a solar module according to a second embodiment.

[0025] Fig. 1 and Fig. 2 each show a cross-sectional view of various solar modules according to the state of the art. To describe the Fig. 1 and Fig. 2, please refer to the introduction to the description.

[0026] Fig. 3 shows a cross-sectional view of a solar module according to a first preferred embodiment. Fig. 3 solar module corresponds to the one in Fig. 1, with the difference that it still has the additional layer 8. The additional layer 8 has a segmented shape and is arranged in a grid-like or strip-like manner in or on the rear-side element 5. This grid structure is spatially positioned such that the additional layer 8 extends into all areas in or on the rear-side element 5 that lie between the solar cells 3 in a vertical view of the solar module. Thus, the additional layer 8 reflects infrared radiation that passes through the rear embedding material 4, which is optically darkened by the additive 6, and can still be absorbed by one of the solar cells 3 upon oblique reflection and / or scattering.

[0027] Fig. 4 shows a cross-sectional view of a solar module according to a second preferred embodiment. Fig. 4 solar module corresponds to the one in Fig.2, with the difference that the additional layer 8 is arranged between the back grid 7, which contains the additive 6, and the back element 5. Both the back grid 7 and the additional layer 8 are arranged between the solar cells 3, i.e. in the intercellular spaces, in a plan view of the solar module. The back grid 7 can be wider than the intercellular spaces. In the plan view of the solar module, a spatial overlap of the additional layer 8 with the back grid located thereon in relation to the solar cells 3 has the advantage that positioning tolerances between the solar cells 3 and the back element 5 are compensated for and the overall visual appearance of the solar module always appears uniformly dark. List of reference symbols: 1 front panel element 2 front embedding material 3 solar cells 4 rear embedding material 5 Rear element 6 Additive 7 rear grilles 8 additional shift

Claims

[1] Solar module, comprising - a front element (1) and a rear element (5), - a front embedding material (2) which rests against the front element (1), - a rear embedding material (4) which rests against the rear element (5), - a plurality of electrically interconnected solar cells (3) which are arranged between the front embedding material (2) and the rear embedding material (4) and are weather-resistantly encapsulated in an encapsulation volume by means of the front element (1), the rear element (5) and the front embedding material (2) and rear embedding material (4) enclosing the solar cells (3) in the form of a laminate, - wherein an additional layer (8) is formed between the rear embedding material (4) and the rear element (5), which additional layer reflects wavelengths of 800 nm or longer wavelengths and - wherein the rear embedding material (4) comprises an additive (6) and / or the additional layer (8) comprises an additive (6) on its side facing the rear embedding material (4), wherein the additive (6) is transparent at wavelengths of 800 nm or longer wavelengths and is designed to absorb at wavelengths below 800 nm and wherein so much additive (6) is present that areas of the solar module laminate provided with the additive appear dark-colored to the human eye in sunlight. [2] Solar module according to claim 1, characterized by that the additional layer (8) contains a white dye. [3] Solar module according to claim 1 or 2, characterized by that the additional layer (8) is arranged in or on the rear side element (5) in a grid-like or strip-like manner, so that the additional layer (8) is arranged in regions which, in a plan view of the solar module, are arranged between the solar cells (3). [4] Solar module according to one of the preceding claims, characterized by that the additive (6) is added to the rear embedding material (4) in such a way that the rear embedding material (4) has a black color appearance over its entire surface in the visible spectral range. [5] Solar module according to one of the preceding claims 1 to 3, characterized by that the additive (6) is arranged in regions of the rear embedding material (4) or in regions of the additional layer (8) which are arranged between the solar cells (3) in a plan view of the solar module. [6] Solar module according to one of the preceding claims, characterized by that the back element (5) is printed, laminated and / or coated with the additional layer (8). [7] Solar module according to one of the preceding claims, characterized by that the additive (6) is at least one pigment. [8] Solar module according to one of the preceding claims, characterized bythat the additional layer (8) contains TiO2. [9] Solar module according to one of the preceding claims, characterized by that the solar module is designed as a bifacial solar module. [10] Solar module according to one of the preceding claims, characterized by that the majority of solar cells (3) are tandem solar cells or TopCon solar cells or solar cells with bifaciality.

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