Method for interconnecting photovoltaic cells by contact between two assemblies

Abstract

The present invention relates to a method for interconnecting photovoltaic cells (4), each comprising collecting fingers, characterized in that it comprises the following successive steps: positioning a plurality of photovoltaic cells (4), according to transverse rows in contact with first metal wires (F1) of a first front assembly (A1), or in contact with second metal wires (F2) of a second rear assembly (A2), forming transverse rows of photovoltaic cells (4) interconnected in series, the ends of the first metal wires (F1) being connected to first connecting elements (e1) and the ends of the second metal wires (F2) being connected to second connecting elements (e2);bringing into contact the first front assembly (A1) and the second rear assembly (A2) for the electrical connection of the first connector elements (e1) and the second connector elements (e2) forming longitudinal rows of photovoltaic cells (4) interconnected in parallel. Figure for the abbreviation: Figure 11;

Description

Title of the invention: Method for interconnecting photovoltaic cells by contact between two assemblies. TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to the general field of photovoltaic modules, which comprise a set of photovoltaic cells electrically connected to each other, and preferably so-called "crystalline" photovoltaic cells, that is to say, those based on monocrystalline or multicrystalline silicon.

[0002] More specifically, the invention relates to the field of interconnecting photovoltaic cells which allows the formation of chains or series (or "strings" in English) of photovoltaic cells.

[0003] The invention can be implemented for many applications, in particular for buildings such as homes or industrial premises (tertiary, commercial, ...), for example for the construction of their roofs, for the design of street furniture, for example for public lighting, road signage or even the charging of electric cars, and can also be used for mobile applications, in particular for integration on cars, buses or boats, among others.

[0004] The invention thus relates to a method for interconnecting photovoltaic cells by bringing a first front assembly into contact with a second rear assembly, as well as a method for manufacturing an associated photovoltaic module. PRIOR TECHNOLOGY

[0005] A photovoltaic module is an assembly of photovoltaic cells arranged side by side between a first transparent layer forming one face of the photovoltaic module and a second layer forming a rear face of the photovoltaic module.

[0006] The first layer forming the front face of the photovoltaic module is advantageously transparent to allow the photovoltaic cells to receive a light flux. It is traditionally made of a single sheet of glass, with a thickness typically between 2 mm and 4 mm, classically around 3 mm.

[0007] The second layer forming the back face of the photovoltaic module can be made of glass or metal, among other materials. It is often formed by a polymeric structure based on an electrically insulating polymer, for example polyethylene terephthalate (PET) or polyamide (PA), which may be protected by one or more layers based on fluorinated polymers, such as polyvinyl fluoride. (PVF) or polyvinylidene fluoride (PVDF), and having a thickness of approximately 400 pm.

[0008] Photovoltaic cells, which are in the form of thin plates approximately 180 pm thick, can be electrically connected to each other (interconnected) by front and rear electrical contact elements, called connecting conductors, and formed for example by strips (or ribbons) or wires of tinned (or sheathed) copper, in particular respectively arranged against the front faces (faces facing the front face of the photovoltaic module intended to receive a light flux) and rear faces (faces facing the rear face of the photovoltaic module) of each of the photovoltaic cells.

[0009] Furthermore, the photovoltaic cells, located between the first and second layers forming the front and rear faces of the photovoltaic module respectively, can be encapsulated. Typically, the encapsulant chosen is an elastomer (or rubber) type polymer, and may, for example, consist of two layers (or films) of poly(ethylene-vinyl acetate) (EVA) between which the photovoltaic cells and the cell connecting conductors are arranged. Each encapsulant layer can have a thickness of at least 0.2 mm and a Young's modulus typically between 2 and 400 MPa at room temperature.

[0010] A classic example of a photovoltaic module 1 comprising crystalline photovoltaic cells 4 has thus been partially and schematically represented, respectively in cross-section on [Fig.1] and in exploded view on [Fig.2].

[0011] As described previously, the photovoltaic module 1 has a front face 2, generally made of transparent tempered glass approximately 3 mm thick, and a rear face 5, for example made of a polymer sheet, opaque or transparent, single-layer or multi-layer, having a Young's modulus greater than 400 MPa at room temperature.

[0012] Between the front 2 and rear 5 faces of the photovoltaic module 1 are located the photovoltaic cells 4, electrically connected to each other by connecting conductors 6 and immersed between two front 3a and rear 3b layers of encapsulating material both forming an encapsulating assembly 3.

[0013] Furthermore, Figures 1 and 2 also show the junction box 7 of the photovoltaic module 1, designed to receive the wiring necessary for the operation of the photovoltaic module 1 and connecting the copper strips of the photovoltaic cell circuit 4. Typically, this junction box 7 is made of plastic or rubber and is completely sealed. Finally, although not shown in Figures 1 and 2, an aluminum frame is provided around all the layers described above to complete the photovoltaic module 1.

[0014] Thus, a photovoltaic module 1 comprises a multitude of identical photovoltaic cells 4 connected in series and / or parallel to provide the output voltage and / or current required to power electrical devices. The most common module format uses 60 square, or "pseudo-square," cells, 156 mm on each side, arranged in six strings or series S, as shown in [Fig. 2], also called "strings" in English, of ten cells interconnected in series. The six strings S of photovoltaic cells 4 are also interconnected in series.

[0015] The photogenerated charge carriers, which contribute to the electric current of the photovoltaic cell 4, are collected by means of an electrode array deposited on the front face of the cell. These electrodes, also called collection fingers, are narrow, typically less than 45 µm in size. They are generally formed by screen printing from a silver-containing paste. The rear face of the cell is generally covered with another electrode array (as in the case of bifacial cells). The electric current then flows from one cell to the other in the string S via interconnections.

[0016] The present invention relates to the interconnection of photovoltaic cells. Interconnection technologies are varied and generally adapted to the solar cell technologies used to create photovoltaic modules. The way in which solar cells are connected to each other can improve the performance of the photovoltaic module independently of that of the individual solar cells, and also reduce so-called CTM (Cell-To-Module) losses.

[0017] Two main techniques are classically distinguished for interconnecting photovoltaic cells in a string: ribbon interconnections and wire interconnections. These usually involve copper wires or ribbons coated with a fusible coating, for example, based on tin and lead, or tin, silver, and copper (SAC for SnAgCu). These two techniques are respectively illustrated in Figures 3 and 4.

[0018] In [Fig. 3], the interconnections between the cells 4 consist of copper strips 6a coated with a fusible alloy, typically a tin-lead alloy or a tin-silver-copper alloy. These rectangular-section strips 6a are soldered onto conductive tracks called "busbars" and formed, during the metallization step of the photovoltaic cell 4, simultaneously with the collector fingers 8 by screen printing. The busbars electrically connect the collector fingers 8 and are oriented perpendicular to the collector fingers 8.

[0019] A 156.75 mm x 156.75 mm (M2) cell generally has six 0.6 mm wide ribbons, these ribbons having a thickness of approximately 0.2 mm. Each ribbon 6a connects the front face of one cell 4 to the rear face of the next cell 4 in the chain (not shown in [Fig.3]). The series connection of the photovoltaic cells 4 using the strips 6a is carried out in a fully automated manner, in equipment called a "stringer".

[0020] For a long time, six-busbar technology (known as 6BB) was predominant on the market, but the development of multi-wire technology has led to an increase in the number of buses to nine or even more, which is now called "Multi-Busbar (MBB)". In addition to their power output on photovoltaic modules, these MBB technologies allow for better module performance in accelerated aging tests, a reduction in the amount of silver paste, and therefore a reduction in production costs.

[0021] These MBB technologies are particularly well known through the "MultiWire" technology, developed by the company "Schmid" and described in the article "Multi-busbar solar cells and modules: high efficiencies and low silver consumption," S. Braun et al., Energy Procedia, vol. 38, pp. 334-339, 2013, which increases the number of busbars deposited on the cell from three to fifteen, and welds a 200 µm diameter wire to each busbar. This technology is illustrated schematically in [Fig. 4]. The 6b wires are made of copper and coated with a thin layer of a tin-lead or tin-silver-copper alloy with a melting point above 210°C. The busbars have a discontinuous shape. They consist of 9 metallization pads, approximately 500 µm x 700 µm, which can be aligned on the collecting fingers 8 as shown here.The metallization pads 9 and the collecting fingers 8 are generally made by screen printing a silver paste. The soldering of the 6b wires to the pads 9 takes place immediately after the 6b wires are placed on the pads 9, in the same equipment, by heating these elements to a temperature above the melting point of the metal alloy coating the wires (on the order of 200°C to 240°C). This melts the alloy coating the 6b copper wires. This technology has been widely adopted worldwide and allows, for example, the soldering of 12 to 15 wires with diameters of 250 µm to 350 µm using infrared beams.This technology can also be applied to certain types of photovoltaic cells, such as silicon heterojunction (SHJ) cells which exhibit sensitivity to temperatures close to 200°C, by carrying out the soldering under restrictive conditions, in particular by selecting certain metallization pastes optimized for soldering and with a short soldering peak, for example by infrared radiation, and a coating with a bismuth-based alloy, for example SnPbBi 42 / 37 / 21 with a melting temperature between 118°C and 122°C.

[0022] The interconnection of photovoltaic cells can also be achieved by depositing a conductive polymer adhesive, called ECA for "Electrically Conductive Adhesive", directly onto the busbars or pads on both sides of the cells. Within Using a stringer, this deposition can be achieved through a dispensing process, for example by inkjet or other dispensing valve technology. Industrially, ECA deposition is performed by screen printing, which offers the advantage of being able to create localized deposits on a wide variety of cells.

[0023] Furthermore, the “SmartWire” technology, also known as SWCT®, developed by the company “Meyer Burger,” registered under DE 102 39 845 Cl and also described in the article “Smart Wire Connection Technology,” T. Söderström et al., Proceedings of the 28th European Photovoltaics Solar Energy Conference, pp. 495–499, 2013, consists of depositing a mat of 18 to 36 wires with a diameter of 200 µm or 250 µm directly onto the collector fingers. In other words, the photovoltaic cells are busbar-free. The wires are held by a polyolefin support film, for example, which is bonded to each side of the cells. The wires have a copper core and an outer coating made of a low-melting-point alloy (SnAgBi).This alloy has a melting point between 120°C and 150°C, which allows the electrical connection between the wires and the collector fingers to be made not during the cell interconnection stage (by localized heating around 100°C), but during the lamination stage of the photovoltaic modules (which is done at a higher temperature, generally around 150-160°C). This technology, by eliminating the need for screen printing on the busbars, reduces silver consumption. The use of a large number of wires, more than 18, reduces resistive and optical losses in order to increase the performance of the photovoltaic modules.

[0024] Figures 5 and 6 illustrate the principle of the "SmartWire" technology. [Fig. 5] schematically illustrates, in cross-section, the application of the support film 10 onto the silkscreen 11 of the photovoltaic cell 4, and [Fig. 6] schematically illustrates, in cross-section, the electrical interconnection obtained from the cell 4 of [Fig. 5] after application of the support film 10.

[0025] Thus, the wires 6b are held by the support film 10 which comprises a fluoropolymer layer 13, for example, and an adhesive layer 14 of acrylic, elastomer (or rubber), polyvinyl ether, ethylene-vinyl acetate (EVA) or epoxy type, on which the wires 6b are placed. As can be seen in [Fig. 5], this support film 10 is then pressed onto the screen printing 11 of the cell 4, this screen printing 11 comprising the collection fingers 8, to obtain the structure of [Fig. 6]. Furthermore, in these figures 5 and 6, we can also see that an anti-reflective layer 12 is provided between the photovoltaic cell 4 and the silkscreen 11. This anti-reflective layer 12 is typically an indium tin oxide layer (or ITO for "Indium Tin Oxide" in English) or a silicon nitride (SiN) layer.

[0026] The wire-shaped interconnections allow for a reduction in the length of the collecting fingers compared to the three-busbar configuration (see [Fig.3]), Because the number of wires is greater than the number of ribbons, this increase in the number of interconnections does not necessarily impact the shading of the photovoltaic cell due to the smaller wire size. However, it allows for a significant reduction in the amount of silver used to print the collector fingers. Since the collector fingers are shorter, their width can be reduced, or a paste with a lower silver content, and therefore lower conductivity, can be used for equivalent series resistance. Furthermore, thanks to their circular cross-section, the metallic wires have a lower effective shading effect on the photovoltaic cell than flat ribbons. Thus, for a set of interconnections with the same cross-sectional area, the shading rate on cells interconnected by wires is lower than that on cells interconnected by ribbons.

[0027] Standard interconnection using ribbons or multi-wires has drawbacks. In this method, the copper ribbons or wires are connected to the front face of the first cell and to the back face of the adjacent second cell. This type of interconnection has the disadvantage of creating mechanical stresses at the edges of the photovoltaic cells and imposing a minimum distance between the cells. A variant of this method is paving, which involves an overlap of approximately one millimeter between the cells, eliminating the space between them while retaining the interconnecting ribbons. In this case, the stresses remain, and part of the cell is shaded, resulting in a loss of active surface area and therefore power to the photovoltaic module.

[0028] Another interconnection method, known as "shingling," involves cutting the photovoltaic cells into strips and interconnecting them in a shingled fashion without the use of ribbons. More specifically, in this method, the photovoltaic cells are cut into 1 / 6 cell sizes and then assembled in a shingled fashion using a conductive adhesive. In this case, there is also an added thickness at the interconnection point, which can lead to mechanical breakage during the lamination of the photovoltaic module. Given the length of the cell metallization lines, this type of connection increases the series resistance of the modules. For example, in the case of heterojunction (HJT) cells, where the metallization lines are poorly conductive, it is necessary to increase the amount of silver deposited, for example, by more than 30% to 40% compared to interconnection using ribbons or wires. Description of the invention

[0029] The invention aims to remedy at least partially the needs mentioned above and the disadvantages relating to the achievements of the prior art.

[0030] In particular, it aims to simplify the process of interconnecting photovoltaic cells by avoiding in particular any constraint on the edges of the cells.

[0031] The invention thus relates, according to one of its aspects, to a method for interconnecting photovoltaic cells, the photovoltaic cells each being covered with a metallized grid having collecting fingers, characterized in that it comprises the following successive steps:

[0032] - the step of positioning a plurality of photovoltaic cells, according to transverse rows extending in a transverse direction, the collecting fingers being oriented in a longitudinal direction perpendicular to the transverse direction, in contact with first metal wires, oriented in the longitudinal direction, of a first front assembly, or in contact with second metal wires, oriented in the longitudinal direction, of a second rear assembly, forming transverse rows of photovoltaic cells interconnected in series, the ends of the first metal wires being connected to first connector elements and the ends of the second metal wires being connected to second connector elements,

[0033] - the step of bringing the first front assembly and the second assembly into contact rear for the electrical connection of the first connector elements and the second connector elements forming longitudinal rows of photovoltaic cells interconnected in parallel.

[0034] The interconnection method according to the invention may further comprise one or more of the following characteristics taken individually or in any possible technical combinations.

[0035] The metal grid may advantageously include a silkscreen print of the collection fingers.

[0036] Each photovoltaic cell can advantageously be devoid of a busbar type conductive track, also called a collection bus.

[0037] Furthermore, each photovoltaic cell can have a cut-out format, resulting from a cut-out into N parts, N being an integer greater than or equal to 2, in particular equal to 6, of the format of a reference photovoltaic cell, in particular a reference photovoltaic cell of type Mx or Gx where x designates an integer greater than or equal to 0, in particular between 0 and 12.

[0038] In addition, each photovoltaic cell can have a width, measured along the transverse direction, of between 156 mm and 210 mm.

[0039] The first metal wires and / or the second metal wires may be wires consisting of a core of a single metal, in particular copper, and a coating of a metal alloy, in particular of the type SnPb, SnPbBi, SnAgBi or SnAgCu.

[0040] In addition, the positioning step of the plurality of photovoltaic cells may include positioning the photovoltaic cells in juxtaposition with each other, without overlap between them, in particular with a spacing between two adjacent photovoltaic cells of between 0 and 0.5 mm.

[0041] Furthermore, the invention also relates, according to another aspect, to a method for manufacturing a photovoltaic module comprising:

[0042] - a first layer forming the front face of the photovoltaic module,

[0043] - a plurality of photovoltaic cells arranged side by side and connected electrically between them,

[0044] - an assembly encapsulating the plurality of photovoltaic cells, the assembly encapsulating material being formed by a front layer of encapsulating material and a rear layer of encapsulating material arranged on either side of the photovoltaic cells,

[0045] - a second layer forming the rear face of the photovoltaic module, the assembly encapsulating and the plurality of photovoltaic cells being located between the first and second layers, at least one of the first and second layers being transparent and intended to receive a luminous flux,

[0046] characterized in that it comprises the step of interconnecting the photovoltaic cells by means of an interconnection process as defined above.

[0047] The manufacturing process may include the step of forming a first front assembly, comprising:

[0048] - a first front frame defined by two front longitudinal uprights, parallel to the longitudinal direction, and two front transverse uprights, parallel to the transverse direction, perpendicular to the longitudinal direction,

[0049] - the first layer extending between the front longitudinal uprights and the transverse uprights at the front of the first front frame,

[0050] - the front layer of encapsulation material extending into contact with the first layer,

[0051] - a plurality of first front metal wires extending transversely between the two front transverse uprights of the first front frame in contact with the front layer of encapsulation material,

[0052] - a plurality of first connector elements arranged on the uprights longitudinally forward, the first metal wires being connected to the first connector elements.

[0053] Furthermore, the manufacturing process may include the step of forming a second rear assembly, comprising:

[0054] - a second rear frame defined by two parallel, longitudinal rear uprights to the longitudinal direction, and two rear transverse uprights, parallel to the transverse direction, perpendicular to the longitudinal direction,

[0055] - the second layer extending between the rear longitudinal uprights and the rear transverse uprights of the second rear frame,

[0056] - the rear layer of encapsulation material extending into contact with the second layer,

[0057] - a plurality of second rear metal wires extending transversely between the two rear transverse uprights of the second rear frame in contact with the rear layer of encapsulation material,

[0058] - a plurality of second connector elements arranged on the uprights rear longitudinal, the second metal wires being connected to the second connector elements.

[0059] The manufacturing process may include the step of positioning an insulating material in contact with the first connection elements and / or in contact with the second connection elements.

[0060] Furthermore, the photovoltaic cell interconnection step may include bringing the first front assembly and the second rear assembly into contact, which may be followed by a sealing step around the photovoltaic module, in particular by positioning at least one sealing joint around the photovoltaic module, in particular between the first front frame and the second rear frame, between the first front frame and the first layer and / or between the first rear frame and the second layer.

[0061] The interconnection step of the photovoltaic cells can be followed by a brazing step.

[0062] Furthermore, the manufacturing process may include a hot lamination step at a temperature greater than or equal to 90°C, in particular greater than or equal to 100°C, in particular greater than or equal to 120°C, in particular less than 180°C, in particular less than 170°C, in particular between 150°C and 180°C, or even between 160°C and 170°C, and for a lamination cycle duration of at least 10 minutes, of the constituent layers of the photovoltaic module.

[0063] The brazing step can be carried out during the hot lamination step.

[0064] In addition, the steps of the interconnection process and / or the manufacturing process can be carried out in an automated manner, in particular by means of handling robots.

[0065] It should also be noted that the term “transparent” means that the material of the first layer and / or the second layer is at least partially transparent to visible light, allowing at least about 80% of this light to pass through.

[0066] Furthermore, the term "encapsulating" should be understood to mean that the plurality of photovoltaic cells is arranged in a volume, for example, hermetically sealed against moisture, at least partially formed by at least one layer composed of a polymer material called an encapsulating material. Generally, at least two encapsulating layers are used, positioned on either side of the photovoltaic cells and joined together after assembly, particularly by lamination, to form the encapsulating assembly. Thus, initially, that is, before any assembly operation, the encapsulating assembly may consist of at least two layers of encapsulating material, called core layers, between which the plurality of photovoltaic cells is encapsulated.However, during the assembly operation, the encapsulation material(s) melt to form, after the assembly operation, only a single solidified layer (or set) in which the photovoltaic cells are embedded or encapsulated.

[0067] The encapsulating assembly can in particular be made from at least one polymer material chosen from: poly(ethylene-vinyl acetate) (EVA), ionomers, polyolefins, vinyl acetals, such as polyvinyl butyrals (PVB), polyvinyl chlorides (PVC), polydimethylsiloxanes, polyurethanes (PU) or polymethyl methacrylate (PMMA), ethylene methyl acrylate (EMA), ethylene butylacrylate (EBA), ethylene propylene (EPM / EPDM).

[0068] The first layer can be made of glass, or of at least one polymer material, such as polymethyl methacrylate (PMMA), polycarbonate (PC), impregnated glass or carbon fibers, among others. The second layer can be made of glass, metal, or of at least one polymer material such as polymethyl methacrylate (PMMA), polycarbonate (PC), impregnated glass or carbon fibers, among others.

[0069] Furthermore, the encapsulating assembly can preferably be made from two layers of poly(ethylene-vinyl acetate) (EVA) between which the photovoltaic cells are arranged.

[0070] Photovoltaic cells may be selected from: homojunction or heterojunction photovoltaic cells based on monocrystalline silicon (c-Si) and / or multicrystalline silicon (mc-Si), and / or photovoltaic cells comprising at least one material from among amorphous silicon (a-Si), microcrystalline silicon (pC-Si), cadmium telluride (CdTe), copper indium selenide (CIS), and copper indium / gallium diselenide (CIGS). Furthermore, the photovoltaic cells may have a thickness ranging from 1 to 300 µm.

[0071] The photovoltaic module may also include a junction box, intended to receive the wiring necessary for the operation of the photovoltaic module.

[0072] The interconnection method and the manufacturing method according to the invention may include any of the previously stated characteristics, taken in isolation or in any technically possible combinations with other characteristics. DESCRIPTION OF THE FIGURES

[0073] Other advantages, purposes and special features of the invention will become apparent from the following non-limiting description of at least one embodiment of the present invention, with reference to the accompanying figures, in which: • Figure [1] shows, in cross-section, a classic example of a photovoltaic module comprising crystalline photovoltaic cells, • Fig. 2 represents, in exploded view, the photovoltaic module of Fig. 1. • Figures 3 and 4 schematically represent two prior art techniques for interconnecting photovoltaic cells, • Figure 5 schematically illustrates, in cross-section, the application of an electrode to the silkscreen of a photovoltaic cell according to the "SmartWire" interconnection principle. • Figure [Fig. 6] schematically illustrates, in cross-section, the electrical interconnection obtained from the photovoltaic cell of Figure [Fig. 5] after application of the electrode, • Figure 7 schematically represents, from a view in a plane formed by the transverse and longitudinal directions, the formation of the first front assembly according to the manufacturing process according to the invention. • Figure 8 schematically represents, from a view in a plane formed by the transverse and longitudinal directions, the formation of the second rear assembly according to the manufacturing process according to the invention. • Figure 9 schematically represents the installation of the photovoltaic cells on the second rear assembly of Figure 8 according to the interconnection method according to the invention, • Figure 10 schematically represents the placement of the first front assembly of Figure 7 onto the second rear assembly of Figure 9 according to the interconnection method according to the invention, • [Fig.1 1] schematically illustrates, in longitudinal section, the contacting of the first front assembly of [Fig.7] and the second rear assembly of [Fig.9], • [Fig. 12] illustrates the final assembly obtained after contacting [Fig. 11], • Figure 13 schematically represents, in cross-section, an example of a photovoltaic module obtained after bringing the first front assembly of Figure 7 into contact with the second rear assembly of Figure 9, and • [Fig. 14] schematically represents, according to a view in a plane formed by the transverse and longitudinal directions, an example of a photovoltaic module obtained by means of a manufacturing process according to the invention.

[0074] Throughout these figures, identical references may designate identical or analogous elements.

[0075] Furthermore, the different parts shown in the figures are not necessarily to a uniform scale, in order to make the figures more legible. DETAILED DESCRIPTION OF THE INVENTION

[0076] Figures 1 to 6 have already been described previously in the section relating to the prior art and the technical context of the invention. The elements common to Figures 1 to 6 and to Figures 7 to 14 are therefore not described again.

[0077] Furthermore, it should be noted that a photovoltaic module 1 obtained by the manufacturing process according to the invention may comprise constituent layers similar to those described with reference to Figures 1 and 2, which are therefore not described again.

[0078] With reference to figures 7 to 14, we will now describe the principles of interconnection of photovoltaic cells 4 and of manufacture of a photovoltaic module 1 according to the invention.

[0079] Advantageously, the interconnection of the photovoltaic cells 4 uses metallic wires Fl, F2, described below, and in particular copper wires, which come into contact with collection fingers 8 present on the photovoltaic cells 4. Furthermore, the photovoltaic cells 4 are chosen to be without busbars or collection buses. Also, each photovoltaic cell 4 is chosen to be of type BB0. The elimination of busbars on the photovoltaic cells 4 can eliminate alignment problems and also reduce cost.

[0080] Furthermore, as with the interconnection method known as "tiling" or "shingle" described above, each photovoltaic cell 4 has a segmented format, resulting from a division into N parts, N being an integer greater than or equal to 2, of the format of a reference photovoltaic cell, in particular a reference photovoltaic cell of type Mx or Gx where x denotes an integer greater than or equal to 0, in particular between 0 and 12. Advantageously, such Cutting can be used to limit the electric current. Thus, for example here, each 4 photovoltaic cell can correspond to 1 / 6 of a reference photovoltaic cell (full cell).

[0081] Advantageously, the invention eliminates constraints on the edges of the photovoltaic cells 4 since there is no overlap of cells, nor any added thickness due to ribbons or wires. The invention allows for densification of the photovoltaic module 1, as in the cases of "shingle" or "paving" described previously, but without loss of active area. Furthermore, in the case of HJT-type cells, there is no increase in silver consumption compared to conventional interconnection.

[0082] The invention also allows for an increased throughput, reaching nearly 10,000 cells / hour, and a simplification of the interconnection process. Thus, all the steps described below can be carried out automatically, particularly with equipment including handling robots.

[0083] Figure 7 represents the formation of a first assembly before Al intended for forming a photovoltaic module 1.

[0084] This first front assembly Al includes first of all a first front frame CL Just like the second rear frame C2 described later, this first front frame Cl serves both as a support for the interconnecting wires but also as protection and stiffening of the photovoltaic module 1.

[0085] The first front frame Cl is defined by two front longitudinal uprights L1 spaced apart from each other, parallel to a longitudinal direction L, and two front transverse uprights Tl spaced apart from each other, parallel to a transverse direction T, perpendicular to the longitudinal direction L.

[0086] Furthermore, although not visible in [Fig. 7] but shown in [Fig. 13], the first assembly before Al still includes a first layer 2, here glass for example, extending between the longitudinal uprights before L1 and the transverse uprights before T1 of the first frame before CL

[0087] In addition, the first front assembly Al also includes a front layer of encapsulation material 3a extending into contact with the first layer 2, and intended to form part of the encapsulating assembly 3 of the photovoltaic module 1.

[0088] Figure 7 also represents the first metal wires before Fl which extend parallel to each other and transversely between the two transverse uprights before Tl of the first frame before Cl in contact with the front layer of encapsulation material 3a (see [Fig. 13]).

[0089] At the ends of the first metal wires before Fl are the first connector elements arranged on the longitudinal supports before LL

[0090] Furthermore, [Fig.8] represents the formation of the second rear assembly A2 intended to form the photovoltaic module 1.

[0091] Similar to the first front assembly A1, this second rear assembly A2 comprises a second rear frame C2 defined by two rear longitudinal uprights L2 spaced apart, parallel to the longitudinal direction L, and two rear transverse uprights T2 spaced apart, parallel to the transverse direction T.

[0092] In addition, the second rear assembly A2 includes a second layer 5, not shown in [Fig.8] but visible in [Fig. 13], intended to form the rear face of the photovoltaic module 1, which extends between the rear longitudinal uprights L2 and the rear transverse uprights T2 of the second rear frame C2.

[0093] The second rear assembly A2 also includes a rear layer of encapsulating material 3b extending into contact with the second layer 5, here for example made of glass, intended to form part of the encapsulating assembly 3.

[0094] Second metal wires F2 extend parallel to each other and transversely between the two rear transverse uprights T2 of the second rear frame C2 in contact with the rear layer of encapsulation material 3b.

[0095] In addition, second connector elements e2 are arranged on the rear longitudinal uprights L2 and are connected to the ends of the second metal wires F2.

[0096] To prevent any short circuit between the first metal wires before Fl and the second metal wires behind F2 when the first Al and second A2 assemblies are brought into contact, an insulating material 15 is positioned in contact with the first connecting elements e1 and / or in contact with the second connecting elements e2. Here, as shown in [Fig. 8], several insulating materials 15 are positioned in contact with the second connecting elements e2. It should be noted that the insulating material 15 may already be integrated beforehand and that this intermediate step of depositing the insulating material may be optional in this case.

[0097] Subsequently, as shown in [Fig. 9], the photovoltaic cells 4 are placed in contact with the second metal wires F2 of the second rear assembly A2. The photovoltaic cells 4 are positioned in transverse rows RT, here 6 photovoltaic cells 4 in each transverse row RT. In addition, they form longitudinal rows RL, here 6 longitudinal rows RL. It should be noted that, in this example, each photovoltaic cell 4 corresponds to 1 / 6 of a reference cell, so six transverse rows RT are equivalent to one transverse row of 6 reference cells.

[0098] During the positioning of the photovoltaic cells 4, the collecting fingers 8 are oriented along the longitudinal direction L while the second metal wires F2 are oriented along the transverse direction T.

[0099] In this way, 30 transverse RT rows of 4 interconnected photovoltaic cells are formed here. In general, it may be possible to form up to one hundred such transverse RT rows.

[0100] Furthermore, Figures 10 and 11 illustrate the step of bringing the first front assembly Al ([Fig. 7]) and the second rear assembly A2, comprising the photovoltaic cells 4 ([Fig. 9]), into contact for the electrical connection of the first connector elements e1 and the second connector elements e2, forming longitudinal rows RL of photovoltaic cells 4 interconnected in parallel. This connection is made automatically when the two frames Cl, C2 are brought into contact. [Fig. 13] also illustrates the structure obtained after the first Al and second A2 assemblies are brought into contact.

[0101] It should be noted that each photovoltaic cell can, for example, have a width, measured along the transverse direction T, of between 156 mm and 210 mm. Furthermore, the photovoltaic cells 4 can be placed side by side, without overlapping, with a spacing between two adjacent photovoltaic cells 4 of between 0 and 0.5 mm. The density in W / m² of the photovoltaic module 1 can thus be increased.

[0102] When obtaining the photovoltaic module 1 by such a manufacturing and interconnection process, sealing joints 16 may be present on the periphery of the layers 2 and 5, here made of glass, and of the frames Cl, C2 in order to ensure sealing, as seen in [Fig. 13].

[0103] Furthermore, it should be noted that the interconnection of the photovoltaic cells 4 can be followed by a brazing step. This can be carried out directly after assembly or during a lamination step depending on the type of metallic coating of the wires Fl, F2. The lamination step can be a hot lamination step, in particular at a temperature greater than or equal to 90°C, or even greater than or equal to 100°C, or even greater than or equal to 120°C, and in particular at a temperature less than or equal to 180°C, or even less than or equal to 170°C, preferably between 150°C and 180°C, or even between 160°C and 170°C, and for a lamination cycle duration of at least 10 minutes.

[0104] Furthermore, [Fig. 14] shows an example of a photovoltaic module 1 obtained by means of a manufacturing process according to the invention. Here, the module is a "60-cell equivalent" module, i.e., half of a so-called 120-cell butterfly module, with 60 transverse rows RT of six cells connected in series. 4 photovoltaic cells of type 1 / 6 of a reference cell. Such a photovoltaic module 1 then comprises 6 longitudinal rows RL.

[0105] Of course, the invention is not limited to the embodiments just described. Various modifications can be made to them by a person skilled in the art.

Claims

Demands

1. A method for interconnecting photovoltaic cells (4), the photovoltaic cells (4) each being covered with a metallized grid having collecting fingers (8), characterized in that it comprises the following successive steps: - the step of positioning a plurality of photovoltaic cells (4), in transverse rows (RT) extending in a transverse direction (T), the collecting fingers (8) being oriented in a longitudinal direction (L) perpendicular to the transverse direction (T), in contact with first metal wires (F1), oriented in the longitudinal direction (L), of a first front assembly (A1), or in contact with second metal wires (F2), oriented in the longitudinal direction (L), of a second rear assembly (A2), forming transverse rows (RT) of photovoltaic cells (4) interconnected in series,the ends of the first metal wires (F1) being connected to first connector elements (el) and the ends of the second metal wires (F2) being connected to second connector elements (e2), - the step of bringing the first front assembly (Al) and the second rear assembly (A2) into contact for the electrical connection of the first connector elements (el) and the second connector elements (e2) forming longitudinal rows (RL) of photovoltaic cells (4) interconnected in parallel.

2. Interconnection method according to claim 1, wherein each photovoltaic cell (4) is devoid of a busbar-type conductive track.

3. Interconnection method according to claim 1 or 2, wherein each photovoltaic cell (4) has a cut-out format, resulting from a cut-out into N parts, N being an integer greater than or equal to 2, in particular equal to 6, of the format of a reference photovoltaic cell, in particular a reference photovoltaic cell of type Mx or Gx where x denotes an integer greater than or equal to 0, in particular between 0 and 12.

4. An interconnection method according to any one of the preceding claims, wherein each photovoltaic cell (4) has a width, measured along the transverse direction (T), between 156 mm and 210 mm.

5. Interconnection method according to any one of the preceding claims, wherein the first metal wires (F1) and / or the second metal wires (F2) are wires consisting of a core of a single metal, in particular copper, and a coating of a metal alloy, in particular of the SnPb, SnPbBi, SnAgBi or SnAgCu type.

6. Interconnection method according to any one of the preceding claims, wherein the positioning step of the plurality of photovoltaic cells (4) comprises positioning the photovoltaic cells (4) in juxtaposition with each other, without overlap between them, in particular with a spacing between two adjacent photovoltaic cells (4) of between 0 and 0.5 mm.

7. A method for manufacturing a photovoltaic module (1) comprising: - a first layer (2) forming the front face of the photovoltaic module (1), - a plurality of photovoltaic cells (4) arranged side by side and electrically connected to each other, - an encapsulating assembly (3) for the plurality of photovoltaic cells (4), the encapsulating assembly (3) being formed by a front layer of encapsulating material (3a) and a rear layer of encapsulating material (3b) arranged on either side of the photovoltaic cells (4), - a second layer (5) forming the rear face of the photovoltaic module (1), the encapsulating assembly (3) and the plurality of photovoltaic cells (4) being located between the first (2) and second (5) layers, at least one of the first (2) and second (5) layers being transparent and intended to receive a luminous flux,characterized in that it comprises the step of interconnecting the photovoltaic cells (4) by means of an interconnection method according to any one of the preceding claims.

8. A manufacturing method according to claim 7, comprising the step of forming a first front assembly (A1), comprising: - a first front frame (C1) defined by two front longitudinal uprights (L1), parallel to the longitudinal direction (L), and two front transverse uprights (Tl), parallel to the transverse direction (T), perpendicular to the longitudinal direction (L), - the first layer (2) extending between the front longitudinal uprights (Ll) and the front transverse uprights (Tl) of the first front frame (Cl), - the front layer of encapsulation material (3a) extending into contact with the first layer (2), - a plurality of first front metal wires (Fl) extending transversely between the two front transverse uprights (Tl) of the first front frame (Cl) in contact with the front layer of encapsulation material (3a), - a plurality of first connection elements (el) arranged on the front longitudinal uprights (Ll), the first metal wires (Fl) being connected to the first connection elements (el).

9. A manufacturing method according to claim 7 or 8, comprising the step of forming a second rear assembly (A2), comprising: - a second rear frame (C2) defined by two rear longitudinal uprights (L2), parallel to the longitudinal direction (L), and two rear transverse uprights (T2), parallel to the transverse direction (T), perpendicular to the longitudinal direction (L), - the second layer (5) extending between the rear longitudinal uprights (L2) and the rear transverse uprights (T2) of the second rear frame (C2), - the rear layer of encapsulation material (3b) extending into contact with the second layer (5), - a plurality of second rear metal wires (F2) extending transversely between the two rear transverse uprights (T2) of the second rear frame (C2) in contact with the rear layer of encapsulation material (3b), - a plurality of second connector elements (e2) arranged on the rear longitudinal supports (L2), the second metal wires (F2) being connected to the second connector elements (e2).

10. A manufacturing method according to claim 8 or 9, comprising the step of positioning an insulating material (15) in contact with the first connection elements (el) and / or in contact with the second connection elements (e2).

11. A manufacturing method according to claims 8 and 9, wherein the interconnection step of the photovoltaic cells (4) comprises bringing the first front assembly (A1) and the second rear assembly (A2) into contact, which is followed by a sealing step around the photovoltaic module (1), in particular by positioning at least one sealing joint (16) around the perimeter of the photovoltaic module (1), in particular between the first front frame (C1) and second rear frame (C2), between the first front frame (C1) and the first layer (2) and / or between the first rear frame (C2) and the second layer (5).

12. A manufacturing method according to any one of claims 7 to 11, wherein the interconnection step of the photovoltaic cells (4) is followed by a brazing step.

13. A manufacturing method according to any one of claims 7 to 12, comprising a hot lamination step at a temperature greater than or equal to 90°C, in particular greater than or equal to 100°C, in particular greater than or equal to 120°C, in particular less than 180°C, in particular less than 170°C, in particular between 150°C and 180°C, in particular between 160°C and 170°C, and for a lamination cycle duration of at least 10 minutes, of the constituent layers of the photovoltaic module (1).

14. A manufacturing method according to claims 12 and 13, wherein the brazing step is carried out during the hot lamination step.

15. A method according to any one of the preceding claims, wherein the steps are carried out automatically, in particular by means of manipulation robots.

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