MODULE PHOTOVOLTAIQUE BIFACIAL

Abstract

A bifacial photovoltaic module (100) comprises at least three photovoltaic junctions that are successively offset along a direction of radiation penetration through the module. Lateral junctions (1, 2) of the module have bandgap values ​​that are greater than the bandgap value of a medial junction (3) of said module. In addition, the module has a configuration with at least two pairs of electrical connection terminals (B1, B1', B2, B2', B3, B3'), and achieves voltage matching between junction branches that are electrically connected in parallel. The module is thus optimized to produce a greater amount of electricity when it receives radiation (R1, R2) simultaneously on two opposite faces (F1, F2) of said module. (Shortcut figure: Figure 1)

Description

Title of the invention: BIFACIAL PHOTOVOLTAIC MODULE technical field

[0001] The present description relates to a bifacial photovoltaic module, as well as a method of electricity production which uses such modules. Previous technique

[0002] The design and installation of bifacial photovoltaic panels have recently been considered for several markets, such as agrivoltaics, building-integrated photovoltaics, ground-mounted solar farms, etc. Bifacial photovoltaic panels provide access to particularly high quantities of electricity produced per unit of occupied ground area, thanks to the use of both sides of each panel to collect and convert solar radiation. Indeed, one side receives direct and diffuse solar radiation, while the other side simultaneously receives diffuse ambient daytime radiation and / or radiation that is reflected or scattered by the ground. The ground's capacity to reflect a portion of the ambient radiation is called its albedo. It depends on the nature of the surface soil, for example, vegetation, gravel, snow, etc.and helps to direct radiation towards the side of the photovoltaic panel that is not facing the Sun. The increase in electricity production thus made possible by bifacial photovoltaic panels, compared to photovoltaic panels with only one side used to collect radiation, can typically be between 5% and 30%.

[0003] Furthermore, to more efficiently convert into electricity the radiation incident on a face of a solar panel, it is known to design superpositions of several photovoltaic junctions, whose bandgap values ​​decrease in the direction of radiation propagation through the superimposed junctions. Thus, it is known to place on a substrate a first silicon-based photovoltaic junction, which is covered by a second perovskite-based photovoltaic junction, so that the radiation passes first through the perovskite-based junction and then through the silicon-based junction. The perovskite-based junction is transparent in a spectral range that corresponds to the maximum efficiency of the silicon-based junction, so that the structure, often called a tandem, is suitable for more efficiently converting radiation from the solar spectrum.

[0004] For example, the article entitled “Benefits of bifacial solar cells combined with low voltage power grids at high latitudes”, by Sami Jouttijârvi et al., Renewable Sustainable Energy Reviews 161 (2022), 112354, reports the use of tandem combinations of silicon- and perovskite-based junctions in bifacial photovoltaic panels: a lower junction is silicon-based and an upper junction is perovskite-based for each radiation incident on one of the two faces of the photovoltaic panel. The authors of this article also mention the general advantage of providing separate pairs of electrical connection terminals for each of the photovoltaic junctions, to prevent one junction from limiting the electrical current that could be produced by the other. A tandem structure thus has four connection terminals.

[0005] Finally, document WO 2016 / 198898 A1 discloses a monolithic stack of three photovoltaic junctions for a bifacial module, comprising a first perovskite-based junction, an intermediate silicon-based junction, and a second perovskite-based junction. In this way, the photovoltaic module exhibits an improved bifacial coefficient, since each direction of radiation propagation in the junction stack first passes through a junction with a larger bandgap value before the intermediate junction with a smaller bandgap value. The bifacial coefficient for a bifacial photovoltaic module is defined as the quotient of its photovoltaic conversion efficiency for radiation incident on the rear face of the module divided by its efficiency for radiation incident on the front face of the module. Technical problem

[0006] From this situation, one object of the present invention is to provide new bifacial photovoltaic panel modules, which are capable of producing quantities of electricity greater than those of the modules known in the prior art.

[0007] Another object of the invention is to provide bifacial photovoltaic panel modules for which the limitation of electric current which is caused by at least one junction on another is avoided.

[0008] Another further object of the invention is to provide bifacial photovoltaic panel modules which have high values ​​for the bifaciality coefficient. Summary of the invention

[0009] To achieve at least one of these goals or another, a first aspect of the invention proposes a bifacial photovoltaic module, arranged to produce electricity from a first radiation incident on a first face of the module and simultaneously from a second radiation which is incident on a second face of the module, parallel and opposite to the first face, during use of the module.

[0010] The module of the invention comprises at least three photovoltaic junctions, each extending parallel to its first and second faces and successively offset along a direction of penetration of the module between these first and second faces. The three junctions comprise a central junction, a first lateral junction located between the first face and the central junction, and a second lateral junction located between the central junction and the second face. In this module of the invention, the band gap of the first lateral junction and the band gap of the second lateral junction are each greater than the band gap of the central junction.

[0011] The bifacial photovoltaic module of the invention further comprises a first A pair of electrical connection terminals arranged to conduct an electric current produced by one of the photovoltaic junctions, called the first dissociated junction, along a first electric current path that is separated from at least two other junctions. It further includes at least one other pair of electrical connection terminals arranged to conduct another electric current produced by at least one of the photovoltaic junctions other than the first dissociated junction, along another electric current path that is separated from the first dissociated junction.

[0012] In other words, for a three-junction photovoltaic module, the first pair of electrical connection terminals collects the electric current produced by one of the three photovoltaic junctions without this current passing through the other two junctions. One or two other electric currents produced by these last two junctions are collected by one or two other pairs of electrical connection terminals without these other currents passing through the first junction. This is why the first junction is said to be dissociated. Thus, the electric current produced by the first dissociated junction is not likely to be limited by the electrical conductivity of one of the other junctions.Furthermore, these other junctions can themselves be dissociated, in which case the module has three pairs of electrical connection terminals, or associated, in which case the module may have only two pairs of electrical connection terminals. Thanks to such dissociation of at least one of the photovoltaic junctions of the module, this module is capable of producing greater quantities of electricity.

[0013] Such a principle of dissociation of at least one of the junctions, according to the invention, applies identically to a photovoltaic module with more than three superimposed junctions. The invention also covers, in particular, a module A photovoltaic module has four or five junctions that are superimposed between the two faces. For a five-junction photovoltaic module, the module comprises the following ordered sequence from one face to the other: first outer lateral junction, first intermediate lateral junction, middle junction, second intermediate lateral junction, and then second outer lateral junction. Preferably, the bandwidth of the first (respectively, second) outer lateral junction is greater than that of the first (respectively, second) intermediate lateral junction, which is itself greater than that of the middle junction. For a four-junction photovoltaic module, one of the two intermediate junctions in the preceding sequence is omitted.

[0014] Furthermore, the module of the invention may have a structure that is symmetrical between the two opposite directions of radiation from one face to the other, by using junction types for the lateral junctions that are similar or have similar characteristics, and by using an electrical connection structure that is symmetrical for all the junctions of the module. In this case, the bifacial coefficient of the module can be high.

[0015] In particular, the photovoltaic module of the invention may have two or three pairs of electrical connection terminals.

[0016] When the module has three pairs of electrical connection terminals, i.e., it has six terminals, it includes second and third pairs of electrical connection terminals in addition to the first pair. The second pair of electrical connection terminals is then arranged to conduct a second electric current produced by a second photovoltaic junction, called the second dissociated junction and distinct from the first dissociated junction, according to a second electric current flow path that is separate from the first electric current flow path.The third pair of electrical connection terminals is arranged to conduct a third electric current produced by a third of the photovoltaic junctions, called the third dissociated junction and distinct from each of the first and second dissociated junctions, according to a third electric current flow path that is separate from the first and second electric current flow paths.

[0017] For such a configuration with three pairs of electrical connection terminals, the module can comprise three distinct substrates: a first substrate which supports the first dissociated junction and the first pair of electrical connection terminals, a second substrate which supports the second dissociated junction and the second pair of electrical connection terminals, and a third substrate which supports the third dissociated junction and the third pair of electrical connection terminals.

[0018] According to an improvement of the invention for a configuration with three pairs of electrical connection terminals, each of the junctions among the middle junction, the first lateral junction, and the second lateral junction can be divided into a plurality of cells that are electrically connected in series to form at least one respective branch. Each branch of one of the junctions is separated from each branch of each other junction and extends between the two electrical connection terminals of the corresponding junction. The module then further comprises two electrical connection nodes, each of which is connected to one of the electrical connection terminals of each junction, so that all branches are electrically connected in parallel within the module.Furthermore, the number of cells in each branch is such that the result of multiplying the number of cells by the maximum power operating voltage value for each branch's junction is essentially the same for all branches. In this case, the respective maximum power operating voltage values ​​for the first and second lateral junctions may differ, particularly to correspond to different average power values ​​of the incident radiation on the two faces of the module. These average values ​​may depend, in particular, on which of the first and second faces of the module is intended to face the Sun, and on the albedo value of the ground toward which the other face is intended to face when the photovoltaic module is used to produce electricity.The respective numbers of cells in the branches of the first and second lateral junctions are also different, resulting in approximately equal total electrical voltages across all branches. Furthermore, the dimensions of the cells in the first and second lateral junctions are such that the respective branch lengths of these first and second lateral junctions are equal to, or divisors of, the length of the central junction. The module assembly can thus be simplified while optimizing its dimensions, since the junctions then have dimensions compatible with the use of a common peripheral frame for the mechanical support of the entire module.

[0019] When the module has two pairs of electrical connection terminals, i.e., it has four terminals, the so-called other pair of electrical connection terminals is arranged so that the so-called other path of electrical current flows successively through at least two of the photovoltaic junctions other than the first disconnected junction, which are then called at least two associated junctions. Thus, these associated junctions are electrically connected to each other in a series connection mode.

[0020] For such a configuration with two pairs of electrical connection terminals, the module can comprise two distinct substrates: a first substrate which supports the first dissociated junction and the first pair of electrical connection terminals, and a second substrate which together supports the at least two associated junctions and the other pair of electrical connection terminals.

[0021] According to an improvement of the invention for a configuration with two pairs of electrical connection terminals, the first dissociated junction can be divided into a plurality of first cells that are electrically connected in series to form at least one first branch. Furthermore, the two associated junctions can also be divided into a plurality of second cells that are electrically connected in series to form at least one second branch. This second branch is separate from each first branch, but each second cell then comprises the respective cells of the two associated junctions, which are electrically combined with each other according to the series connection method within that second cell. As before, each of the first and second branches connects two electrical connection nodes of the module, such that all branches are electrically connected in parallel within the module.Furthermore, the respective numbers of first or second cells in each first or second branch are such that a result of multiplying for each first branch the number of first cells in that first branch by a value of maximum power operating voltage relative to the first dissociated junction, is substantially equal to a result of multiplying for each second branch the number of second cells in that second branch by a value of maximum power operating voltage relative to the series connection of the two associated junctions.

[0022] Possibly, the cells inside each junction branch, lateral or median, can be grouped into subsets, the cells inside each subset being connected in series, and the subsets of the same branch also being connected in series.

[0023] Possibly also, the cells of each junction, lateral or median, can be grouped into several branches for this junction, all these branches being electrically connected in parallel in the module.

[0024] Possibly, the cells of each junction branch, lateral or median, can be electrically connected to each other according to any hybrid combination of the series connection mode and the parallel connection mode.

[0025] Generally speaking, for the invention, the photovoltaic junctions of the module can advantageously be of the following types: Median injunction may be of a silicon-based type and have a band gap that is between 1.0 eV (electron-volt, 1 eV = 1.6*10 19 joule) and 1.2 eV, and each of the first and second side junctions can be of a perovskite-based type and have a band gap width that is between 1.3 eV and 1.9 eV.

[0026] Finally, a second aspect of the invention relates to a method for producing electricity which comprises placing at least one photovoltaic module conforming to the first aspect of the invention at a location on Earth, such that the faces of this module each form an angle of between 24° and 40° with respect to a direction that is horizontal at that location on Earth. Such an inclination of the photovoltaic module allows its bifacial structure to be used to produce a greater quantity of electricity. Brief description of the figures

[0027] The features and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments, with reference to the accompanying figures, among which:

[0028] [Fig. 1] is a cross-sectional view of a photovoltaic module which conforms to the invention, and which has a configuration with three pairs of electrical connection terminals;

[0029] [Fig.2] illustrates a junction breakdown of the photovoltaic module of [Fig. 1] into cells, as well as the electrical connections that link the cells;

[0030] [Fig.3] is a plan view of a silicon-based junction such as can be used in the photovoltaic module of [Fig.1];

[0031] [Fig.4a] is a plan view of a perovskite-based junction such that it can be combined with the junction of [Fig.3] in the photovoltaic module of [Fig.1];

[0032] [Fig.4b] is a plan view of another perovskite-based junction such that it can be combined with the junctions of [Fig.3] and [Fig.4a] in the photovoltaic module of [Fig.1];

[0033] [Fig.5a] is an exploded perspective view of an assembly of the junctions of the photovoltaic module of [Fig.l];

[0034] [Fig.5b] is a perspective view of the photovoltaic module of [Fig.l], after assembly;

[0035] [Fig.6] corresponds to [Fig.1] for another photovoltaic module which is also in accordance with the invention, but which has a configuration with two pairs of electrical connection terminals;

[0036] [Fig.7] corresponds to [Fig.2] for the other photovoltaic module of [Fig.6]; and

[0037] [Fig. 8] illustrates the installation conditions of a photovoltaic module which is in accordance with the invention. Detailed description of the invention

[0038] For clarity, the dimensions of the elements shown in these figures do not correspond to actual dimensions or ratios of actual dimensions. Furthermore, some of these elements are represented only symbolically, and identical reference numerals shown in different figures designate identical elements or elements with identical functions.

[0039] The embodiments of the invention described below all correspond to a sequence of photovoltaic junctions of the following type: a first perovskite-based lateral junction, a silicon-based medial junction, and a second perovskite-based lateral junction. The band gap value for a silicon-based junction is on the order of 1.12 eV, and that for a perovskite-based junction is on the order of 1.6 eV. These two types of photovoltaic junctions are well known to those skilled in the art, and reference may be made to one of the many available publications that describe them, in particular the article entitled "Multi-junction solar cells paving the way for super high-efficiency", by M. Yamaguchi et al., Journal of Applied Physics, 129, 240901 (2021).However, each perovskite junction can be replaced by a junction of another type with a band gap greater than that of the central junction. For example, each perovskite junction can be replaced by a type III / V junction, such as a GalnP (gallium-indium-phosphorus) junction, an organic photovoltaic system, or a dye-sensitized photovoltaic cell. The silicon junction, which constitutes the central junction, can be of any design, including those designated by the acronyms IBC (Interdigitated Back Contact), PERC (Passivated Emitter and Rear Cell), TOPCON (Tunnel Oxide Passivated Contact), or HJT (HeteroJonction Technology). It can also be replaced for this application by a junction of another type with a band gap less than that of each side junction.For example, the mid-junction can alternatively be of the CdTe (cadmium telluride) or CIGS (copper, indium, and gallium selenide) type.

[0040] The three junctions are arranged parallel to each other inside a photovoltaic module and parallel to the faces of this module. The middle junction is located between the first and second lateral junctions, regardless of the positions of transparent substrates that may be used to support these junctions and may be located at any level relative to the junction sequence. The two opposite faces of the photovoltaic module are equally transparent, so that solar radiation, reflected radiation, and / or diffuse radiation enter the panel through these faces and then incident on the junctions. By convention, the front face of the module, called the first face, is intended to be oriented The module's rear face, called the second face, is designed to be oriented primarily away from the Sun during operation, receiving both direct solar radiation and diffuse daylight radiation. The module's rear face, referred to as the second face, is intended to be oriented primarily away from the Sun during operation, receiving both diffuse daylight radiation and radiation reflected by the ground according to its ground surface albedo value.

[0041] According to [Fig. 1], the photovoltaic module designated by reference numeral 100 and conforming to the invention may comprise: - a first transparent substrate 10, for example made of glass, which supports a first lateral photovoltaic junction 1 of the perovskite type. The junction 1 may comprise from the substrate 10: a first electrically conductive transparent electrode 11, for example based on fluorine-doped tin oxide (SnO2:F) or tin-doped indium oxide (ITO), an electronic transport layer 12, denoted ETL, a perovskite-based active layer 13, denoted PKT, a hole transport layer 14, denoted HTL, and a second electrically conductive transparent electrode 15, for example based on tin-doped indium oxide; - a silicon-based substrate that supports or incorporates a silicon-type photovoltaic junction 3, denoted Si, for example of type IBC, PERC, TOPCON or HJT; and - a second transparent substrate 20, for example of glass, that supports a second lateral perovskite-type photovoltaic junction 2. The junction 2 may comprise, from the substrate 20: another first electrically conductive transparent electrode 21, for example based on fluorine-doped tin oxide or tin-doped indium oxide, another electronic transport layer 22, denoted ETL, another perovskite-based active layer 23, denoted PKT, another hole transport layer 24, denoted HTL, and another second electrically conductive transparent electrode 25, for example based on tin-doped indium oxide.

[0042] Advantageously, the sequence of materials with their thicknesses that constitutes junction 2 can be identical to that of junction 1, just as substrates 10 and 20 can be identical. Junction 3 is intermediate between junctions 1 and 2 and constitutes the medial junction. Substrates 10 and 20 are preferably close to that of junction 3, on either side of it, with each of junctions 1 and 2 facing the substrate of junction 3. An encapsulation sheet 40 is intercalated between junctions 1 and 3, and another encapsulation sheet 50 is intercalated between junctions 2 and 3. The encapsulation sheets 40 and 50 can be identical, made of a transparent and electrically insulating material such as polyolefin, for example.For such a configuration of module 100, substrate 10 can constitute its front face, denoted Fl and intended to be turned towards the Sun when using module 100 to produce electricity. Substrate 20 then constitutes the rear face. of module 100, labeled F2 and intended to be oriented away from the Sun, towards the ground. In [Fig. 1], RI generally designates the radiation that reaches the front face Fl of module 100, and R2 generally designates the radiation that reaches its rear face F2.

[0043] The junction 1, based on perovskite, is provided with two electrical connection terminals: terminal B1 which is in electrical contact with electrode 11, and terminal B1' which is in electrical contact with electrode 15. Similarly, the junction 2, also based on perovskite, is provided with two other electrical connection terminals: terminal B2 which is in electrical contact with electrode 21, and terminal B2' which is in electrical contact with electrode 25. Finally, the junction 3, based on silicon, also has two electrical connection terminals: B3 which is positive and B3' which is negative. When using panel 100 to produce electrical current, terminals Bl, B2 and B3 are electrical current output terminals from junctions 1, 2 and 3, respectively, and terminals Bl', B2' and B3' are electrical current return terminals to the respective junctions.Each of the photovoltaic junctions 1, 2, and 3 has a dedicated pair of terminals, resulting in a total of three pairs of electrical connection terminals. To connect module 100 to an external electrical circuit, terminals B1, B2, and B3 must be connected together on one hand, and B1', B2', and B3' on the other. In other words, the three junctions 1, 2, and 3 are to be electrically connected to each other in a parallel configuration between nodes N and N', as symbolically represented in [Fig. 1]. Thus, each junction can produce an individual electrical current, without this individual current passing through either of the other two junctions. As defined in the general part of this description, each of the three junctions 1, 2, and 3 is independent of each of the other two.Therefore, it is not necessary to match the junctions to each other with regard to their respective capacity to conduct an external electric current. This results in a simplification of the entire module 100, as well as the removal of a limitation on the electrical power supplied.

[0044] However, such a module 100 with a parallel electrical connection for junctions 1, 2, and 3 operates optimally when the electrical voltages across these junctions, taken separately from one another, are substantially equal. To achieve this, according to an improvement of the invention, each junction 1, 2, or 3 can be divided into a plurality of cells that are electrically connected in series within each junction, so as to constitute a respective branch of the parallel connection. Thus, the perovskite-based junction 1 is divided into identical NPKti cells that are connected in series on the substrate 10. Similarly, the perovskite-based junction 2 is divided into two identical NPKt cells that are connected in series on the substrate 20. A person skilled in the art knows how to create such junction cell divisions, which are supported by the same substrate and electrically connected in series, for example, by means of etched patterns and conductive connections commonly designated as P1, P2, and P3. Junction 3 can be in the form of identical NSi cells connected in series, for example, by reusing a commercially available silicon-based photovoltaic module. The voltage matching condition to be satisfied for optimal operation of the module 100 is then: Npkti*VPk ti = Npkt 2*VPk t2 = Nsi*Vsi, where VPkt u Vpk T2 and Vsi denote the respective output voltage values ​​of junction cell 1, junction cell 2, and junction cell 3. [Fig. 2] schematically shows the electrical configuration resulting from such divisions and connection methods for the module 100.C1 denotes each cell of junction 1, C2 each cell of junction 2, and C3 each cell of junction 3. Possibly, each of junctions 1 and 2 may further exhibit an additional cut (not shown in [Fig.2]), for example as commonly designated by engraving pattern P4, so that this junction consists of several identical branches which are electrically connected in parallel.

[0045] It is then possible to optimize the module 100 in a further measure to obtain maximum electricity production. For this, each cell output voltage value VPKti, VPKt2 and VSi can be taken equal to the maximum power operating voltage value for that cell, i.e. equal to Vmpp_PKTi, Vmpp_pkt2 and Vmpp_si respectively, the abbreviation mpp meaning maximum power point.

[0046] In addition, so that junctions 1, 2 and 3 can be easily superimposed within the same peripheral mechanical retaining frame, and in a way that is optimized for the amount of electricity produced per unit area of ​​module 100, an individual cell size can be adopted for all cells of the same junction, such that all junction branches have peripheral dimensions that coincide.

[0047] For example, lighting conditions intended for module 100 may be the following: - average power of the RI radiation incident on the front face Fl of module 100: 1000 W / m2 (watts per square meter), including direct solar radiation and diffuse daytime radiation; and - average power of the R2 radiation which is incident on the rear face F2 of module 100: 80 W / m2 (watt per square meter), including diffuse daytime radiation and radiation which is reflected by the ground behind module 100. These illumination conditions are met, in particular, when the 100 module is installed in the Marseille region of France, with a 32° (degree) tilt relative to the ground surface, oriented in azimuth towards the south, within a row of solar panels typically at least 7 m (meter) from another parallel row, and for a soil type with an average albedo value between 0.2 and 0.8. Such installation parameters are illustrated in [Fig. 8]. In this figure, S represents the Sun, and T the Earth's surface. Under the lighting conditions just specified, the Vmpp_si value of the maximum power operating voltage of a silicon-based junction 3 C3 cell is 0.62 V. For comparison, the open-circuit voltage value of such a silicon-based photovoltaic cell VOc_si is 0.71 V.

[0048] With a branch consisting of NSi = 72 junction cells C3 electrically connected in series, the maximum power operating voltage between the two electrical connection terminals B3 and B3' of this branch of silicon-based cells is NSi*Vmpp_si = 72 × 0.62 = 44.64 V. A commercially available silicon-based photovoltaic module with such an electrical configuration is shown in [Fig. 3]. It has a rectangular shape, with a length LSi of 1866 mm (millimeters) and a width lSi of 941 mm. In this figure, each silicon-based junction cell C3 comprises a respective substrate of 156 mm x 156 mm, which is separated from that of each other C3 cell, and reference numeral 31 designates segments of electrical connections that constitute the series combination of the 72 C3 cells within the module.The C3 cells are arranged in six rows of twelve cells each in the junction module 3 shown, and the electrical connection segments 31 form a three-way meander parallel to the direction of the length LSi. This silicon-based junction module 3, in its entirety, constitutes one branch of the parallel electrical combination that was described above in connection with [Fig.2].

[0049] For an average radiant power value of 1000 W / m² on the Fl face of module 100, a perovskite-based cell Ci of junction 1 has a maximum power operating voltage value Vmpp_PKti = 0.92 V, while its open-circuit voltage value VOc_pkti is 1.10 V. The branch of such Ci cells, which are connected in series, therefore has the following electrical voltage value between its terminals B1 and Bl': NPKTi*Vmpp_PKn. To satisfy the voltage matching condition with each branch of junction 3 as shown in [Fig. 3], the number NPKTi can be equal to NSi*Vmpp_Si / Vmpp_PKTi = 44.64 / 0.92 ≈ 48.

[0050] Similarly for junction 2, and for the average radiating power value of 80 W / m2 on face F2 of module 100, a perovskite-based cell C2 of junction 2 has the operating voltage value at maximum power Vmpp_PKt2 = 0.85 V, while its open-circuit voltage value VOc_pkt2 is 1.02 V. A branch of NPKt2 such C2 cells which are connected in series therefore has the following electrical voltage value between its terminals B2 and B2': NPKt2 = Vmpp_PKt2 * To satisfy the voltage matching condition with each branch of junction 3, the number NPKt2 is preferably equal to NSi*Vmpp_si / Vmpp_PKt2 = 44.64 / 0.85 = 52.

[0051] The output voltage value of module 100 in electricity production operation, as existing between nodes N and N', is then substantially equal to that of junction module 3 of [Fig.3], i.e. about 44.6 V. But the output current of module 100 is the sum of the individual currents which are produced by the three junctions 1-3 for their respective operations at maximum power.

[0052] Each of the substrates 10 and 20 can advantageously be rectangular with length and width dimensions that are substantially identical to those LSi and lSi of the junction modulus 3. According to a configuration proposed by the inventors, the perovskite-based junction 1 can be divided on the substrate 10, in its width equal to lSi, into four subsets, each consisting of NPKti bands, forming a total of 4*NPKu bands, all of which can have identical individual widths and all have the length LSi. These subsets are designated by lb 12, l3, and l4, respectively in [Fig. 4a], and a different cell Ci is individually constituted by each junction band 1.All the cells Ci of any given subassembly lb 12, I3, and 14 are electrically connected in series within that subassembly, and the subassemblies U, 12, I3, and 14 are electrically connected in parallel between terminals B1 and B1', thus forming separate branches in the connection mode described above. For example, the cells Ci can be connected in series within each of the subassemblies lb 12, I3, and 14 by etching patterns and conductive connections PI, P2, and P3 as already mentioned above, and the subassemblies lb 12, 13, and 14 can be separated by electrical insulation etchings of type P5. Thus, each strip that constitutes a cell Ci on the substrate 10 can have a length equal to LSi and a width lPKTi equal to lSi / (4»NPKTi) ~ 4.9 mm, or rather 4.82 mm by subtracting the thickness of the conductive connections and that of the electrical insulation etchings between adjacent sub-assemblies.

[0053] Similarly, the perovskite-based junction 2 can be divided on the substrate 20, in its width equal to lSi, into four subsets each of NPKt 2 bands, forming in total 4'NPKt 2 bands which can all have widths These subassemblies are identical and all have the length LSi. They are designated 2b 22, 23, and 24, respectively, in [Fig. 4b], and each junction strip 2 individually constitutes a cell C2. All the C2 cells within any given subassembly 2b 22, 23, and 24 are electrically connected in series within that subassembly, and the subassemblies 2b 22, 23, and 24 are electrically connected in parallel between terminals B2 and B2', thus forming separate branches. The C2 cells can also be connected in series within each of the subassemblies 2b 22, 23, and 24 by etching patterns and conductive connections PI, P2, and P3.Thus, each strip that constitutes a C2 cell on substrate 20 can have a length equal to LSi and a width 1PKt 2 equal to 1S; / (4"NPkt 2) ~ 4.5 mm, or rather 4.42 mm by further subtracting the thickness of the conductive connections and that of the electrical insulation grooves between adjacent subassemblies. With reference to the series connection mode of the Ci cells for junction 1, and of the C2 cells for junction 2, the dimension lSi / 4 has been called the branch length of junctions 1 and 2 in the general part of this description. The length of junction 3 as appearing in [Fig. 3] is LSi.

[0054] Possibly, additional cutouts by insulation etchings P4 can be added in each perovskite-based junction 1, 2, to divide each junction branch into several branches which are electrically connected in parallel on each substrate 10, 20, respectively.

[0055] Thanks to the cell dimensions given above, the substrate 10 with junction 1 as described with reference to [Fig. 4a], and that 20 with junction 2 as described with reference to [Fig. 4b], can be assembled with the junction module 3 as described with reference to [Fig. 3], according to [Fig. 1], within a common peripheral frame for mechanical retention. Within this assembly, the parallel electrical connections of all branches can be made in one of the ways known to those skilled in the art, using strips of electrically conductive paste or dedicated connector elements. [Fig.5a] and [Fig.5b] illustrate the assembly of module 100 which is thus achieved: a view of the superimposed junctions 1-3 to form module 100 with the bifacial configuration ([Fig.5a]), and the assembly of the bifacial module 100 in a peripheral mechanical retaining frame 101 ([Fig.5b]).

[0056] Another embodiment of the invention is now described, with two pairs of electrical connection terminals, i.e. four electrical connection terminals.

[0057] As shown in [Fig. 6], the perovskite-based junction 1 and the silicon-based junction 3 now together form a tandem assembly, being supported by the same substrate. This common substrate can be incorporated into the Junction 3. Alternatively, the two junctions 1 and 3 can be implemented as a stack of thin films deposited on a transparent substrate. A recombination or tunnel junction layer 60, denoted INT, is intermediated between the hole transport layer 14 of junction 1 and junction 3, in order to achieve a series connection of these two junctions 1 and 3. For this reason, junctions 1 and 3 have been referred to as connected in the general part of the description for this embodiment. Insulating encapsulation sheets 50 and 70 are arranged on each side of the tandem assembly of junctions 1 and 3, with a protective glass plate 80 placed over sheet 70 to form the front face Fl of the module 100.

[0058] The perovskite-based junction 2, which is supported by the glass substrate 20, can be identical to that described with reference to [Fig. 1]. It also constitutes a junction that is separate from junctions 1 and 3. The electrical connection terminal B2, which is in contact with the transparent conductive electrode 21, is electrically connected via node N to an electrical connection terminal B13, which is in contact with the transparent conductive electrode 11. Furthermore, the electrical connection terminal B2', which is in contact with the transparent conductive electrode 25, is electrically connected via node N' to an electrical connection terminal B13', which is in contact with a transparent conductive electrode 31 of the silicon-based junction 3. Thus, node N forms the current output terminal of module 100, and node N' forms the current return terminal of this module.For this alternative embodiment, module 100 can be oriented so that the tandem assembly of junctions 1 and 3 is on the Sun side, as opposed to junction 2, and with the perovskite-based junction 3 being closest to the Fl front face of the module.

[0059] The maximum power operating voltage value Vmpp_spkt i of the tandem assembly of junctions 1 and 3 is approximately 1.68 V for the lighting conditions mentioned above, while its open-circuit voltage value VOc_si pkt i is approximately 1.96 V. Therefore, by applying the optimization principles set forth above to module 100 of [Fig. 6], the voltage matching of at least one branch of cells Cn of the tandem assembly of junctions 1 and 3 with at least one branch of cells C2 of junction 2 is preferably based on the maximum power operating voltage values ​​Vmpp_Si pkti and Vmpp_PKT2. In other words, the agreement relationship is now: Nsi PKTi*Vmpp_ Si pkti = NpKT2*Vmpp_ pkt2, where Nsi PKTi is the number of tandem assembly Cn cells of junctions 1 and 3 that are connected in series in the corresponding branch. [Fig.Figure 7 schematically shows the electrical configuration thus obtained for module 100 of [Fig. 6]. For example, Nsppkti can be taken as equal to 72 cells and NPKt2 as equal to . 142 cells, resulting in an operating output voltage value for module 100 of approximately 121 V.

[0060] Again, to allow easy and optimal assembly with respect to the amount of electricity produced per unit area of ​​module 100, the respective sizes of the tandem assembly cells Cn of junctions 1 and 3 and of those C2 of junction 2 can be chosen so that the branches of cells connected in series have superimposable dimensions within the same peripheral frame of mechanical support.

[0061] It is understood that the invention can be reproduced by modifying secondary aspects of the embodiments described in detail above, while retaining at least some of the advantages mentioned. In particular, the following modifications can be implemented: - the invention can be applied to any number of photovoltaic junctions assembled in a single module to efficiently absorb radiation in complementary spectral ranges. In particular, five photovoltaic junctions can be superimposed, with band gap values ​​that are all the greater the closer the junction is to one of the faces of the module; - Each photovoltaic junction is divided into cells that can be connected to each other in any combination of series and parallel connections, in order to achieve voltage matching across all the photovoltaic junctions in the module; and - the types of photovoltaic junctions that are assembled together in the module, including the materials of the junctions, can be changed to others.

[0062] Finally, all the numerical values ​​that have been cited have been cited only as examples and may be changed depending on the embodiment considered.

Claims

Demands

1. Bifacial photovoltaic module (100), arranged to produce electricity from a first radiation (RI) which is incident on a first face (F1) of the module and simultaneously from a second radiation (R2) which is incident on a second face (F2) of the module, parallel and opposite to the first face, during use of the module, the module (100) comprising at least three photovoltaic junctions which each extend parallel to the first (F1) and second (F2) faces and are successively offset along a direction of passage through the module between said first and second faces, the three junctions comprising a median junction (3), a first lateral junction (1) located between the first face and the median junction, and a second lateral junction (2) located between the median junction and the second face,in which a forbidden bandwidth of the first lateral junction and a forbidden bandwidth of the second lateral junction are each greater than a forbidden bandwidth of the middle junction, the module (100) having a configuration with two or three pairs of electrical connection terminals, comprising a first pair of electrical connection terminals (B2, B2') arranged to conduct an electric current produced by one of the photovoltaic junctions (1-3), called the first dissociated junction (2), in accordance with a first electric current flow path which is separated from at least two other (1, 3) junctions, and comprising at least one other pair of electrical connection terminals (B1, Bl', B3, B3'; B13, B13') arranged to conduct another electric current produced by at least one of the photovoltaic junctions (1-3) other than said first dissociated junction,according to another electric current flow path which is separated from the first dissociated junction (2), characterized in that the respective numbers of cells in branches of the first (1) and second (2) lateral junctions are different.

2. Module (100) according to claim 1, wherein maximum power operating voltage values ​​are used to determine the respective numbers of cells in the branches of the first (1) and second (2) lateral junctions correspond to average power values ​​of the first (RI) and second (R2) radiations which are different.

3. Module (100) according to claim 1 or 2, comprising in addition to the first pair of electrical connection terminals (B2, B2'), a second (B1, B1') and a third (B3, B3') pair of electrical connection terminals, the second pair of electrical connection terminals (B1, B1') being arranged to conduct a second electric current produced by a second of the photovoltaic junctions, called the second dissociated junction (1) and distinct from the first dissociated junction (2), in accordance with a second electric current flow path which is separate from the first electric current flow path, and the third pair of electrical connection terminals (B3, B3') being arranged to conduct a third electric current produced by a third of the photovoltaic junctions, called the third dissociated junction (3) and distinct from each of the first (2) and second (1) dissociated junctions,in accordance with a third electric current flow path which is separate from the first and second electric current flow paths.

4. Module (100) according to claim 3, comprising first (20), second (10) and third distinct substrates, the first substrate supporting the first dissociated junction (2) and the first pair of electrical connection terminals (B2, B2'), the second substrate supporting the second dissociated junction (1) and the second pair of electrical connection terminals (B1, Bl'), and the third substrate supporting the third dissociated junction (3) and the third pair of electrical connection terminals (B3, B3').

5. Module (100) according to claim 3 or 4, wherein each of the junctions among the middle junction (3), the first lateral junction (2), and the second lateral junction (3) is divided into a plurality of cells (C1, C2, C3) which are electrically connected in series to form at least one respective branch which is separated from each branch of each other junction, and which extends between the two electrical connection terminals (B1, B1', B2, B2', B3, B3') of the corresponding junction, and the module further comprises two electrical connection nodes (N, N') each connected to one of the electrical connection terminals of each junction, so that all branches are electrically connected in parallel within the module, and in which the number of cells in each branch is such that a result of multiplying for each branch the number of cells by a value of maximum power operating voltage relative to the junction of said branch, is substantially equal for all branches.

6. Module (100) according to claim 5, wherein the respective values ​​of maximum power operating voltage which are relative to the first (1) and second (2) lateral junctions, are different, so that the respective numbers of cells in the branches of said first and second lateral junctions are also different, and wherein dimensions of the cells (Ci, C2) of the first and second lateral junctions are such that respective branch lengths of said first and second lateral junctions are equal to a length of the median junction (3), or are divisors of a length of the median junction.

7. Module (100) according to claim 1 or 2, wherein said other pair of electrical connection terminals (B 13, B13') is arranged such that said other path of electric current flow passes successively through at least two of the photovoltaic junctions other than said first dissociated junction (2), called at least two associated junctions (1,3), such that said at least two associated junctions are electrically combined with each other in a series connection mode.

8. Module (100) according to claim 7, comprising two separate substrates, a first (20) of said substrates supporting the first dissociated junction (2) and the first pair of electrical connection terminals (B2, B2'), and another of said substrates supporting together the at least two associated junctions (1, 3) and said other pair of electrical connection terminals (B13, B13').

9. Module (100) according to claim 7 or 8, wherein the first dissociated junction (2) is cut into a plurality of first cells (C2) which are electrically connected in series to form at least one first branch, and the two associated junctions (1,3) are cut into a plurality of second cells (Ci 3) which are electrically connected in series to form at least one second branch which is separated from each first branch, each second cell comprising a respective cell of each of the two associated junctions which are electrically combined with each other in the series connection mode within said second cell, each of the first and second branches connecting two electrical connection nodes (N, N') of the module, such that all branches are electrically connected in parallel within the module, and wherein the respective numbers of first or second cells in each first or second branch are such that a result of multiplying for each first branch the number of first cells in said first branch by a value of maximum power operating voltage relative to the first dissociated junction,that is substantially equal to the result of multiplying, for each second branch, the number of second cells in said second branch by a value of the operating voltage at maximum power relative to the series connection of the two associated junctions.

10. Module (100) according to any one of the preceding claims, wherein the middle junction (3) is of a silicon-based type and has a band gap width of between 1.0 eV and 1.2 eV, and each of the first (1) and second (2) side junctions is of a perovskite-based type and has a band gap width of between 1.3 eV and 1.9 eV.

11. Method of producing electricity comprising placing at a location on Earth at least one photovoltaic module (100) which conforms to any one of the preceding claims, such that the faces (F1, F2) of said module each form an angle which is between 24° and 40° with respect to a direction which is horizontal at said location on Earth.

12. A method according to claim 11, wherein the respective numbers of cells in the branches of the first (1) and second (2) lateral junctions are different to obtain respective total electrical voltages of all branches which are substantially equal with maximum power operating voltage values ​​for each of said first and second lateral junctions which correspond to different average values ​​of incident radiation power on the two faces (F1, F2) of the module.

13. A method according to claim 12, wherein the maximum power operating voltage values ​​used to determine the respective numbers of cells in the branches of the first (1) and second (2) lateral junctions correspond to average power values ​​of the first (RI) and second (R2) radiations which are different depending on which of the first (F1) and second (F2) faces of the module (100) is turned towards the Sun, and according to an albedo value of a ground towards which the other face of said module is turned.

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