Improved Tandem Solar Module

Abstract

Solar module, particularly of the photovoltaic type, comprising a first module (1) composed of thin-film photovoltaic cells, particularly perovskite-based, connected together in series and / or parallel, and a second module (2) composed of silicon-based photovoltaic cells connected together in series and / or parallel. This module is special in that an air gap (3) is arranged between the first and second modules, so as to allow air to circulate between them. Figure 1

Description

Title of the invention: Improved tandem solar module

[0001] The present invention relates to the field of energy production. It concerns a solar module, in particular of the photovoltaic type.

[0002] Photovoltaic modules are composed of silicon cells, generally square in shape with one side measuring between 125 and 217 mm. These cells are electrically connected to each other by series and / or parallel arrangements.

[0003] In the context of efforts to reduce greenhouse gas emissions, photovoltaic electricity production offers promising solutions for the future. Many stakeholders are seeking to improve its performance.

[0004] In particular, cells with two distinct and superimposed active layers have recently appeared; a first layer based on perovskite capable of converting short-wavelength light, and which allows through what it does not convert; and a second layer based on silicon, located beneath the first layer, capable of converting longer-wavelength light. However, such two-layer cells connected in series are limited by the current produced in the layer that produces the least current. And when one wishes to make a solar panel from such cells, optimization is complicated, notably because the solar spectrum is not the same between sunset or sunrise, and midday sun. In addition, hot spot phenomena produced on the silicon cells risk damaging the perovskite cells.

[0005] An object of the present invention is to provide a solar panel that makes it possible to produce electricity in a more efficient, simpler and less expensive way.

[0006] Another object of the present invention is to provide a solar panel with improved surface efficiency and lifespan.

[0007] The present invention aims to address, at least in part, the aforementioned objectives by providing a solar panel, particularly a photovoltaic panel, comprising: - a first module composed of thin-film photovoltaic cells, in particular perovskite-based, connected together in series and / or in parallel; - a second module composed of silicon-based photovoltaic cells connected together in series and / or in parallel.

[0008] characterized in that an air gap is arranged between the first and second modules, so as to allow air to circulate between the first and second modules.

[0009] Thanks to these provisions, the operating conditions of the cells are improved, and their lifespan is extended.

[0010] According to other characteristics: - said air gap may have an average thickness of between 1 and 10 mm, preferably between 5 and 10 mm, allowing for efficient cooling while limiting the increase in thickness, - said panel may be rectangular, and the air gap may open onto both long sides of said solar panel, so that air can enter through one of the long sides and exit through the other long sides, thus allowing natural convection; such an arrangement is particularly advantageous for a panel installed in "landscape" orientation. - said panel may be rectangular and the air gap may open onto both short sides of said solar panel so that air can enter through one of the short sides and exit through the other, thus allowing natural convection; such an arrangement is particularly advantageous for a panel installed in "portrait" orientation. - The electrical currents of each of the two modules can be connected to the same input and output contact, thus simplifying panel management. - said panel may include a third module composed of thin-film photovoltaic cells, in particular perovskite-based, connected together in series and / or in parallel, and the second module may be composed of bifacial cells, and be arranged between the first and third modules, thus allowing the advantages of the invention to be benefited from, whether the sun comes from one side or the other of the panel,

[0011] The present invention also relates to a method for manufacturing a solar panel according to the invention, comprising the following steps: - manufacturing of a first perovskite-based module, comprising the following steps: - installation of a glass panel, - application of a layer of transparent conductive oxide onto the glass plate, - application of a first selective layer of fillers - application of a layer or superposition of layers of absorbers, for example made of perovskites, on the first charge-selective layer, - placement of a second selective charge layer, the charges of the second selective charge layer being in the opposite direction to those of the first selective charge layer - cutting the resulting panel to obtain a plurality of transverse strips, with a length equal to the width of the panel, and a width between 5 and 100 mm, - installation of insulation between the said strips, - machining a longitudinal groove in each strip, to reach the oxide transparent conductor deposited on the glass - Installation of a transparent rear conductor, forming a layer, and fitting into the longitudinal grooves, - longitudinal cut of the rear conductor at the level of each strip, to form one conductive strip per transverse strip, - Module completion steps - manufacturing a second module composed of silicon-based photovoltaic cells connected in series and / or parallel - assembly of the two modules, in such a way as to leave an air gap between the two modules,

[0012] thus enabling the production of a panel according to the invention with reduced costs.

[0013] According to other characteristics: - the panel can be rectangular, and before assembling the two modules, battens can be placed parallel to the short side of the panel on the surface of one of the modules, then the other module can be placed on these battens, allowing natural convection, particularly for panels installed in "landscape" orientation. - the panel is rectangular, and before assembling the two modules, battens parallel to the long side of the panel are placed on the surface of one of the modules, then the other module is placed on these battens, allowing natural convection, especially for panels placed in "portrait" orientation. - before assembling the two modules, pads can be placed on the surface of one of the modules according to a grid parallel to the sides of the panel, then the other module can be placed on these pads, allowing natural convection regardless of the direction in which the panel is placed.

[0014] The present invention will be better understood upon reading the following detailed description, with reference to the accompanying figures in which:

[0015] [Fig-1] is a cross-sectional view of a solar panel according to the invention.

[0016] [Fig.2] is a cross-sectional view of a solar panel according to a particular method of realization implementation of the invention.

[0017] The solar panel according to the invention comprises a first module 1 composed of thin-film cells, for example perovskite-based cells, a second module 2 composed of silicon-based cells, and an air gap 3 between the two; the cells of a module are connected to each other in series and / or in parallel, according to known arrangements. An example is described in document FR2002583 in which about twenty cells are connected in series forming chains, and at least three such chains are connected in parallel.

[0018] In the following, unless otherwise specified, the invention will be described using the example of Perovskite-based thin-film cells. This material is preferred and most commonly used for the invention. However, this does not exclude other possible materials for the thin-film cells, as explained later.

[0019] The second module 2 is composed of silicon-based bifacial cells, capable of absorbing light from each of its faces and transforming it into current.

[0020] According to the invention, the two modules are connected in parallel, so that each of the modules can contribute efficiently with all the amount of electricity that it is capable of producing.

[0021] The two-module panel according to the invention is thus configured so that solar radiation arriving from one side of the panel will first arrive on a layer of perovskite, which will transform part of the radiation into electricity, in particular the part close to the ultraviolet, at short wavelengths; the radiation not absorbed by the perovskite layer passes through it, and arrives at the silicon-based layer, which transforms another part of the received radiation into electricity.

[0022] This combination of two layers allows overall higher conversion efficiencies, up to more than 30%; whereas a single silicon-based layer allows a conversion efficiency of between 22 and 27%.

[0023] Perovskites are materials of general formula ABX3 in which: - A is a cation of methyl ammonium CH3NH3+, formamidinium CH(NH2)2+ or cesium Cs+ - B is a cation of tin Sn2+ or lead PB2+, and - X is a halide anion I-, Br- or Cl-.

[0024] Lead methyl ammonium halides CH3NH3PbX3 are the most commonly used perovskites, preferably lead methyl ammonium triiodide CH3NH3PbI3, with a band gap of 1.75 + / - 0.5 eV; these can be used in combination with a silicon-based panel, having a band gap of about 1.1 eV.

[0025] As an alternative to perovskites, so-called III-V products can also be used, such as Gallium (III) Arsenide (V).

[0026] Cadmium tellurides, or copper gallium or indium selenides, can also be used.

[0027] The panels typically have a length of 2 m and a width of 1 m

[0028] The thickness of the panel composed of the two modules is typically 10 to 20 mm.

[0029] An air gap 3 is arranged between the first module 1 and the second module 2. The Air circulation between the modules allows for cooling of the cells, and therefore an extension of their lifespan.

[0030] Indeed, when a solar panel is in operation and exposed to sunlight, some points may heat up more than others; particularly in the case of shading. Partial damage to certain cells can cause them to develop "hot spots" where the temperature can rise to over 150°C. The cells can then degrade very rapidly.

[0031] According to the invention, the air blade 3 cools the cells, reduces hot spots, and thus allows for an extension of the lifespan of the cells, and therefore of the solar panel.

[0032]

[0033]

[0034]

[0035] According to a preferred embodiment of the invention, the fabrication of a first module 1 composed of thin-film cells, particularly perovskite-based cells, can be carried out according to the following steps: • placement of a glass plate, • application of a layer of transparent conductive oxide onto the glass plate, • application of a first selective layer of fillers • placement of a layer or superposition of layers of absorbers, for example made of perovskite, on the first charge-selective layer, • placement of a second selective charge layer, the charges of the second selective charge layer being in the opposite direction to those of the first selective charge layer • cutting the resulting panel to obtain a plurality of transverse strips, with a length equal to the width of the panel, and a width between 5 and 100 mm, • installation of insulation between the aforementioned strips, • Machining a longitudinal groove in each strip to reach the transparent conductive oxide deposited on the glass, • Installation of a transparent rear conductor, forming a layer, and fitting into the longitudinal grooves, • Longitudinal cut of the rear conductor at each strip, to form one conductive strip per transverse strip, • Module completion steps The two modules are then assembled as follows: • placement on a support of a perovskite-based module, • application of a layer of glass or transparent polymer, • Installation of 4 wedges, • placement of a silicon-based module encapsulated and surrounded on both sides by a layer of glass or transparent polymer. According to a preferred embodiment of the invention, a layer of glass can be chosen for the two external faces of the panel, and a layer of transparent polymer for the internal faces. According to one embodiment of the invention, the shims 4 take the form of blocks distributed according to a grid parallel to the sides of the panel, so as to leave continuous passages in the direction of two adjacent sides of the panel.

[0036] According to another embodiment of the invention, the wedges 4 take the form of cleats all parallel to one side of the panel, so as to leave air passages in the direction of said side of the panel.

[0037] With layers of glass or transparent polymer that are very rigid and mechanically resistant, the studs 4 can be four studs arranged at the four corners of the panel, or the cleats 4 can be two cleats arranged on the two opposite edges of the panel.

[0038] With less rigid layers of glass or transparent polymer, it is possible to provide for more numerous and closer together blocks or cleats 4.

[0039] The cleats 4 can extend over the entire length separating two opposite edges.

[0040] For example, for panels intended to be installed in a "landscape" orientation, their sides Since the longer modules are horizontal, four battens can be placed parallel to the opposite edges of the shorter modules. This allows air to enter from below between the modules and between the battens, and exit from above, creating natural convection.

[0041] For example, for panels intended to be installed in "portrait" orientation, with their longest sides vertical, four battens can be provided parallel to the opposite longest edges. This allows air to enter from below between the modules and between the battens, and to exit from above, creating natural convection.

[0042] The pads 4, or blocks 4, can be made of silicone, or even epoxy, possibly reinforced by one or more glass beads or a rigid polymer. They can also be made of transparent PET, bonded using, for example, silicone or epoxy.

[0043] The thickness of the shims 4 can, for example, be at least 5 mm, to allow air circulation in the layer of air thus formed.

[0044] Depending on the circumstances, a thickness of at least 2 mm may also be suitable, or even a reduced thickness of 1 mm.

[0045] According to a particular embodiment of the invention, a third module 1 composed of thin-film cells, for example based on perovskite, is added, so as to have a module composed of thin-film cells 1 on either side of the silicon-based module 2; the silicon-based module 2 is then configured in bifacial, allowing it to receive solar radiation from both sides.

[0046] A thickness of approximately 15 to 30 mm can then typically be obtained.

[0047] Although the above description is based on particular embodiments, it is in no way limiting of the scope of the invention, and modifications may be made, in particular by substitution of technical equivalents or by different combination of all or part of the features developed above, to arrive at the whole of what is claimed in the following set of claims.

Claims

Claims

1. Solar panel, in particular of the photovoltaic type, comprising - a first module (1) composed of thin-film photovoltaic cells, in particular based on perovskite, connected together in series and / or in parallel - a second module (2) composed of silicon-based photovoltaic cells connected together in series and / or in parallel, characterized in that an air gap (3) is arranged between the first and second modules, so as to allow air to circulate between the first and second modules.

2. Solar panel according to the preceding claim, in which said air blade (3) has an average thickness of between 1 and 10 mm, preferably between 5 and 10 mm.

3. Solar panel according to one of the preceding claims, said panel being rectangular, and the air blade (3) opens onto the two large sides of said solar panel, so that the air can enter through one of the large sides and exit through the other of the large sides.

4. Solar panel according to one of claims 1 or 2, said panel being rectangular, and the air blade (3) opens onto the two short sides of said solar panel so that the air can enter through one of the short sides and exit through the other of the short sides.

5. Solar panel according to the preceding claim, in which the electric currents of each of the two modules are connected to the same input and output contact.

6. Solar panel according to one of the preceding claims, comprising a third module (1) composed of thin-film photovoltaic cells, in particular based on perovskite, connected together in series and / or in parallel, and the second module (2) is composed of bifacial cells, and arranged between the first and third modules (1).

7. Method of manufacturing a solar panel according to claim 1, comprising the following steps: • manufacturing a first module (1) based on perovskite, comprising the following steps: - laying a glass plate, - laying a layer of transparent conductive oxide on the glass plate, - laying a first charge-selective layer - laying a layer or superposition of layers of absorbers, for example made of perovskite, on the first charge-selective layer, - laying a second charge-selective layer, the charges of the second charge-selective layer being in the opposite direction to those of the first charge-selective layer - cutting the panel obtained to obtain a plurality of transverse strips, of length the width of the panel, and of width between 5 and 100 mm, - laying an insulator between said strips, - machining a longitudinal groove in each strip, to reach the transparent conductive oxide deposited on the glass, - laying a transparent rear conductor, forming a layer, and inserting into the longitudinal grooves, - longitudinal cutting of the rear conductor at the level of each strip,to form a conductive strip per transverse strip, - module finishing steps • manufacturing of a second module (2) composed of silicon-based photovoltaic cells connected together in series and / or in parallel • assembly of the two modules, so as to provide an air gap (3) between the two modules.,

8. Method according to the preceding claim, in which the panel is rectangular, and before assembling the two modules, cleats (4) parallel to the short side of the panel are placed on the surface of one of the modules, then the other module is placed on these cleats (4).

9. Method according to claim 7, in which the panel is rectangular, and before assembling the two modules, cleats (4) parallel to the long side of the panel are placed on the surface of one of the modules, then the other module is placed on these cleats (4).

10. Method according to the preceding claim, in which before the assembly of the two modules, we place pads (4) on the surface of one of the modules in a grid parallel to the sides of the panel, then we place the other module on these pads (4).

Images