Increasing the Compression of Solar Modules by Maximized Superposed Connection

Abstract

Photovoltaic device comprising an assembly of several strings (20A, 20B) of cells (101, 102), each of said strings being formed of a plurality of cells aligned in a first direction y, the strings being aligned in a second direction x making a non-zero angle with the first direction and typically orthogonal or substantially orthogonal to the first direction, the cell assembly comprising a first string (20A) laterally overlapped by a second string (20B) of the plurality of strings, such that a peripheral portion (22') of the second string covers a peripheral portion of the first string, the first string (20A) and the second string (20B) being electrically isolated by means of an insulating region (31) interposed between the respective peripheral portions of the first and second strings.

Description

TECHNICAL FIELD AND PRIOR ART

[0001] This application relates to the field of producing photovoltaic modules and provides for an improved assembly of several chains of interconnected solar or photovoltaic cells and in particular photovoltaic cells based on crystalline silicon.

[0002] A conventional solar module is typically made up of several chains of juxtaposed cells commonly called “strings” in Anglo-Saxon terminology.

[0003] A chain or "string" of cells comprises a succession of several cells electrically connected to each other and generally aligned in a given first direction. The connection between cells of the same chain can be made by means of ribbons or conductive wires which extend in the first direction and successively come into contact with at least one upper or lower face of each cell.

[0004] A module generally comprises, in a direction orthogonal to the first direction, several chains of cells parallel to each other.

[0005] To improve the surface power of a photovoltaic module, we can seek to increase the efficiency of the cells and / or seek to densify the active surface of the modules.

[0006] It is known to achieve densification of modules by reducing the inter-cell spaces within the same chain of cells, or even by making the cells of the same chain overlap each other.

[0007] Document US2021202784 describes, for example, a particular way of assembling the cells of a chain of cells in which the cells overlap each other in a shingle-type arrangement, commonly called a "shingle," or, except for the end cells of a chain, each cell overlaps a previous neighboring cell and is overlapped by a next neighboring cell in the succession of cells forming the chain. A structure of the type called "paving" uses a similar arrangement but with ribbons or conductive wires to make the connection between the cells.

[0008] Another type of arrangement provides, except for the end cells of a chain, that each cell is either overlapped by its previous and next neighboring cells, or overlaps its previous and next neighboring cells in the succession of cells.

[0009] The problem arises of finding a new way to improve the surface power of a photovoltaic module. STATEMENT OF THE INVENTION

[0010] The present invention relates in particular to a photovoltaic device comprising an assembly of several strings of cells, this assembly comprising at least a first string laterally overlapped by a second string of cells, the first string and the second string being electrically isolated from each other by means of an insulating region interposed between a peripheral portion of the first string and a peripheral portion of the second string of cells.

[0011] Such an arrangement allows for improved surface density. Electrical continuity between adjacent cells is also achieved while avoiding short circuits.

[0012] Such an arrangement allows for the same number of cells and cell size compared to a conventional arrangement module, to have reduced encapsulation.

[0013] According to one embodiment, the present application relates to a photovoltaic device comprising an assembly of several strings of cells, each of the strings being formed of a plurality of cells aligned in a first direction y, the strings being aligned in a second direction x making a non-zero angle with the first direction and typically orthogonal or substantially orthogonal to the first direction, the assembly of cells comprising at least a first string laterally overlapped by a second string of the plurality of strings, so that a peripheral portion of the second string covers a peripheral portion of the first string, the first string and the second string being electrically insulated by means of an insulating region interposed between the respective peripheral portions of the first string and the second string.

[0014] “Substantially parallel” means here that which makes an angle less than 5° and “substantially orthogonal” means here that which makes an angle greater than 85°.

[0015] Advantageously, the second chain of cells is juxtaposed and laterally overlaps or is laterally overlapped by a third chain of cells.

[0016] The first string of cells may be coated with one or more first conductive track(s) which extend(s) parallel or substantially parallel to the first direction y, the second string of cells being coated with one or more second conductive track(s) which extend(s) parallel or substantially parallel to the first direction y, the first conductive track(s) being connected to the second conductive track(s) via a conductive interconnection zone arranged on a first side of the assembly at a first end of the first string and at a first end of the second string.

[0017] According to a particular embodiment, the second chain of cells is juxtaposed and laterally overlaps or is laterally overlapped by a third chain of cells, the third chain of cells being coated with one or more third conductive track(s) which extend(s) in particular parallel or substantially parallel to the first direction, the third chain of cells being juxtaposed and laterally overlaps or is laterally overlapped by a fourth chain of cells, the fourth chain of cells being coated with one or more fourth conductive track(s) which extend(s) in particular parallel or substantially parallel to the first direction, the first chain, the second chain, the third chain, the fourth chain having a first end located on the first side of the assembly and a second end located on a second side of the assembly opposite the first side of the assembly,the third conductive track(s) being connected to the fourth conductive track(s) via another conductive interconnection zone arranged on the second side of the assembly.,

[0018] Advantageously, the first end and the second end of the first chain are offset relative to, respectively, the first end and the second end of the second chain.

[0019] According to an advantageous embodiment, the cells are of the pseudo-square type, with beveled edges, the cells of the first chain overlapping so that a longitudinal edge of a first cell is arranged opposite the beveled edges of a second cell neighboring the first cell.

[0020] Advantageously, the insulating region is made of or comprises a material having adhesive properties.

[0021] According to one possible implementation, the insulating region can be formed from a material transparent to photons at a wavelength between 200 nm and 1200 nm, in particular between 400 and 800 nm.

[0022] According to one embodiment, the insulating region may be formed from a thermoplastic or thermoset material.

[0023] According to another embodiment, the insulating region may be formed of an inorganic material.

[0024] Advantageously, the insulating region may be formed from a material having a dielectric strength greater than the maximum voltage value (Voc) present between two juxtaposed strings of cells. The insulating region may in particular be formed from a material having a dielectric strength of between 15 and 30 V.

[0025] According to another aspect, the present invention relates to a method of manufacturing a photovoltaic device as defined above.

[0026] According to one embodiment, the method comprises the following steps: assembling a set of solar cells so as to form at least the first string of cells and passivating opposite peripheral portions of the cells of the set of cells and located along lateral edges of the cells, to form the insulating region, then, assembling the first string of cells and the second string of cells by carrying out the lateral overlap of the second string on the first string of cells, the second string of cells being arranged in contact with the insulating region.

[0027] Passivation of the peripheral portions can be performed after a cell assembly step to form the first cell chain.

[0028] Advantageously, the method may comprise the formation of conductive tracks on the first chain and at least one conductive interconnection zone with conductive tracks of a second chain of cells adjacent to the first chain, the conductive interconnection zone being produced after passivation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be better understood on the basis of the following description and the attached drawings in which: There figure 1 illustrates a string of solar cells arranged in a tiling or paving configuration. The figure 2 illustrates an arrangement according to the invention of parallel solar cell strings with lateral overlap between adjacent solar cell strings. The figure 3 illustrates a variant of lateral overlap between adjacent solar cell chains. The figure 4illustrates an intermediate insulating region between adjacent solar cell strings that overlap laterally. The Figure 5 illustrates a first type of arrangement of laterally overlapping solar cell chains. The figure 6 illustrates another type of arrangement of laterally overlapping solar cell strings. Figures 7A , 7B And 7C illustrate a first example of the implementation of the passivation of lateral edges of laterally overlapping cell chains. The Figures 8A, 8B And 8C illustrate an example of carrying out the passivation of lateral edges of cell chains in which the passivation is carried out after the assembly of the cells into cell chains. The Figures 9A, 9B And 9C illustrate an example of carrying out the passivation of lateral edges of cell chains in which the passivation is carried out before assembling the cells into cell chains. The figure 10 illustrates an example of a particular arrangement of adjacent cell chains with adjacent chain ends offset from each other;=.

[0030] Identical, similar or equivalent parts of different figures bear the same numerical references so as to facilitate the transition from one figure to another.

[0031] The different parts represented in the figures are not necessarily on a uniform scale, to make the figures more readable. DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0032] An example of arrangement of a chain 20A (“string” according to English terminology) of solar cells 10 1 ,...,10 12 capable of being integrated into a photovoltaic module as implemented according to the invention is illustrated in the figure 1 .

[0033] The cells 10 1 ,...,10 12 are, in this example, of the pseudo-square or pseudo-rectangular type, with edges 2c beveled obliquely relative to the so-called “lateral” edges 2b and “longitudinal” edges 2a of the cell.

[0034] The lateral edges 2b are those which extend in a first direction, typically parallel or substantially parallel to that of an axis y (of an orthogonal reference frame [O;°x;°y;°z] on the figure 1 ) which here corresponds to the direction in which the chain 20A of cells 10 1 ,...,10 12 extends.

[0035] The longitudinal edges 2a are here those which extend in a second direction in which the chains of the module are distributed. The second direction is typically substantially orthogonal or orthogonal to the first direction, in other words parallel or substantially parallel to that of an axis x of the orthogonal reference frame [O;°x;°y;°z].

[0036] The arrangement of the cells within the chain 20A is here such that from one end to the other of the chain of cells 10 1 ,..., 10 12 , each cell overlaps or is overlapped by an adjacent cell of the succession of cells 10 1 ,...,10 12 forming the chain. Thus, each cell is provided with a longitudinal edge 2a, which is covered by a portion of a neighboring cell or is located at the end of a portion which protrudes opposite the neighboring cell.

[0037] In the illustrated example, each cell 10 1 ,...,10 12 extends in particular in a plane distinct from that in which the other cells 10 1 ,...,10 12 extend respectively. A different arrangement within the chain 20A may however be provided. Thus, as a variant, the cells 10 1 ,...,10 12 may have an arrangement in which the successive cells are arranged alternately in a first plane or in a second plane distinct from the first plane and parallel to the latter.

[0038] The cells 10 1 ,...,10 12 are here electrically connected by means of one or more conductive elements 12 which extend over the cells in the form of conductive strips or conductive wires, for example a silver-based metallic material, and from one end to the other of the chain of cells 10 1 ,...,10 12 . The cells 10 1 ,...,10 12 can thus have an arrangement and a connection according to a tiling configuration ("paving").

[0039] In the particular embodiment illustrated, the conductive elements 12 extend over a so-called “upper” face of the chain of cells formed here by the revealed assembly of the front faces of the cells 10 1 ,...,10 12 .

[0040] The wires 12 may be crushed along the chain assembly of cells 10 1 ,..., 10 12 , in order to limit the mechanical stresses but also to increase the adhesion of the latter to the cells 10 1 ,..., 10 12 . The conductive elements 12 may be fixed by gluing, or welding, or by using a soldering paste. Alternatively, these conductive elements 12 may be arranged on, or integrated into, a layer of polymer material which is added to the cells 10 1 ,..., 10 12 .

[0041] To form a photovoltaic module, the 20A string of cells 10 1 ,..., 10 12 , of cells which has just been described is intended to be assembled with other strings of cells, which are typically connected together in series.

[0042] As a variation of the illustrated configuration example, the cells 10 1 ,...,10 12 may have a shingle configuration with a connection between neighboring cells such that a conductive interconnection area is located between an upper face of a first cell and a lower face of a second cell neighboring the first cell.

[0043] The assembly between chains of cells has the particularity of providing lateral overlap between neighboring chains of cells.

[0044] So, on the figure 2, the lateral overlap between chains of cells is such that a portion 22 of a first chain 20A of cells 10 1 , 10 2 , 10 3 is arranged on a portion (not referenced in this figure) of a second neighboring chain 20B, in other words adjacent to the first. The lateral overlap may be such that an overhang d of, for example, between 0.01 mm and 5 mm, in particular between 0.5 and 1 mm, of a chain of cells 20A on the neighboring chain 20B may be provided.

[0045] In order not to lose or to limit a loss of active zone, the value of this overshoot d (also called "coverage") can advantageously be close to that of a trimming (not shown) typically provided on the rear face of the cells. Such a trimming can correspond to an inactive peripheral zone unlike the active and central one generally coated with transparent conductive material such as ITO (For "indium tin oxide" or indium-tin oxide).

[0046] On the figure 3 , a lateral overlap is also provided between the chains 20A, 20B of cells, but this time so that a portion 22' of the second chain 20B of cells 10' 1 , 10' 2 , 10' 3 covers a portion (not referenced in this figure) of the chain 20A.

[0047] Rather than a simple juxtaposition with strings of cells spaced apart from each other, such lateral overlap contributes to a densification of the photovoltaic module, comprising for example between 2 and 20 strings of parallel cells.

[0048] To allow such lateral overlapping of a string of cells on a neighboring string while avoiding short-circuiting these adjacent strings of cells with each other, an intermediate region 31 made of electrically insulating material 32 is provided. This region 31, called insulating region 31, is thus arranged at least in the overlapping zone and on a portion of the faces of the cells of the string 20A which is overlapped and covered by the cells of the neighboring string 20B.

[0049] The material of the insulating region 31 is preferably provided with optical transparency to photons for a wavelength between 200 nm and 1200 nm.

[0050] The insulating region 31 may be in the form of a layer or a strip, for example made of thermoplastic or thermosetting material, or an insulating film. The insulating material 32 may advantageously be a polymer, for example polyethylene terephthalate (PET). The insulating material 32 may optionally be coated with an adhesive material or may itself have adhesive properties. A layer of PET with acrylic adhesive, such as for example a layer marketed under the name tesa ®< 4129, may for example be used. A layer of insulating material 32, in particular polymer, and having adhesive properties on one of its faces or on both of its faces may be used.

[0051] The insulating region 31 is provided, in terms of composition and thickness, so as to have good dielectric strength and in particular dielectric strength greater than a ratio of a maximum voltage difference in two adjacent strings 20A, 20B of cells and the thickness e T of the device (dimension measured parallel to the z axis on the figure 4 ).

[0052] In the particular case of a region 31 made of insulating material 32, for example polymer, and with an electrical rigidity of the order of 15 kV / mm, a maximum voltage of the order of 17 V between two adjacent chains 20A, 20B (corresponding for example to 12 cells per chain and a voltage of 0.7 V per cell), a thickness ei of at least 2 µm of the insulating polymer is provided in order to ensure the function. Advantageously, the region 31 made of insulating material 32 can be provided with a minimum voltage to be maintained, between 15 V and 30 V.

[0053] Also preferably, the material of the insulating region 31 is chosen so that it retains its dielectric strength properties up to a temperature, for example of the order of 200°C, to which it is likely to be subjected during the module manufacturing process.

[0054] The distribution of the insulating region 31 is not limited to that illustrated in the figure 4 It may eventually extend beyond the intercalated zone between cells of distinct chains.

[0055] Apart from the electrical insulation between adjacent cell chains, the insulating region 31 can have a role of mechanical strength of the assembly between adjacent cell chains. Thus, this insulating region 31 can participate in the integral maintenance of the neighboring cell chains, in particular during the manufacture of the module. In particular during a commonly used lamination step and during which the assembly is subjected to pressure, the insulating region 31 makes it possible to prevent the cell chains from moving relative to each other.

[0056] As with cells within a chain, chains of cells can be arranged together in an arrangement such as in the Figure 5 or an arrangement like on the figure 6 .

[0057] In the first type of arrangement, each chain 20A or 20B or 20C is located in a plane distinct from those in which the other chains 20A, 20B, 20C extend respectively.

[0058] In the second type of arrangement, the chains 20A, 20B, 20C are located alternately in a first plane and in a second plane distinct from the first plane.

[0059] Lateral overlapping assembly of cell strings can be integrated into a conventional module manufacturing process while limiting the addition of additional steps.

[0060] An additional step of passivation of lateral portions of cell chain on which a neighboring chain is intended to rest can be provided.

[0061] Thus, in the example of realization illustrated on the Figures 7A-7B , we first form several chains 20A, 20B, 20C, 20D, 20E, 20F, of cells ( Figure 7A ).

[0062] The chains of cells are then each provided with conductive elements of the ribbon type or conductive wires 12 which extend in the main direction of the chain (in other words the direction in which all the cells of this chain extend).

[0063] Then it is coated with insulating material 32 ( Figure 7B ) peripheral portions 22a, 22b of the cells located along their respective lateral edges 2b, to form the insulating region(s) 31.

[0064] A localized deposition of insulating material directly onto the cell chain, in particular using a liquid phase deposition technique or an inkjet printing technique, or liquid spraying, or dipping, or stamping, can be carried out.

[0065] This passivation step can be carried out using existing equipment and / or equipment adapted to carry out other steps. A chain production machine (a "stringer" in English terminology) or a chain installation machine, or equipment dedicated to the production of chains as well as their assembly can be modified and adapted to carry out such a step.

[0066] A particular technique for depositing the insulating material uses an ink containing a polymer material, preferably thermosetting, and for example based on Epoxy, or silicone, or polyurethane, or acrylic, or acrylate. Baking or crosslinking of the polymer(s) deposited by liquid means can then be carried out conventionally by UV irradiation, or by heating with a suitable variable thermal profile, or directly in air.

[0067] Afterwards ( Figure 7C), connection zones are formed at the ends of the chains of cells 20A, 20B, 20C, 20D, 20E on either side of the assembly, in particular interconnection zones 51 between adjacent cells.

[0068] The implementation of lateral overlapping makes it possible to reduce the quantity of materials used, particularly for encapsulation. The process can be integrated into a photovoltaic module production line without introducing additional costs.

[0069] Passivation of the chain edges may alternatively be carried out before the formation of the 12 parallel conductive lines formed along each chain.

[0070] Thus, in the example of the manufacturing process illustrated in the Figures 8A-8C , we first realize ( Figure 8A ), an assembly of cells in a 20A chain (“string”) of cells 10 1 ,...,10 6 .

[0071] Then ( Figure 8B), an insulating region 31 is formed on the peripheral portions 22a, 22b at the level of the lateral edges 2a of the cells of this chain 20A.

[0072] Then, this 20A chain of cells is assembled with an adjacent chain or a set of chains already assembled, by carrying out a lateral overlap as described previously.

[0073] Thus, a first string 20A of cells is coated with first conductive tracks 12a while the second string 20B of cells is coated with second conductive tracks 12b, the first conductive tracks 12a being connected to the second conductive tracks 12b via an electrically conductive interconnection zone 51A arranged on a first side of the assembly at a first end of said first string 20A and the second string 20B. The second string 20B of cells which is laterally overlapped or laterally overlaps a third string 20C of cells is coated with third conductive tracks 12c. The third string of cells is laterally overlapped or overlaps a fourth string 20D of cells, itself coated with fourth conductive tracks 12d.The third conductive tracks 12c being connected to the fourth conductive tracks 12d via another electrically conductive interconnection zone 51B arranged on a second side of the assembly opposite the first side of the assembly where the interconnection zone 51A of the first and second conductive tracks 12a, 12b is located.

[0074] According to another embodiment variant illustrated on the Figures 9A-9C , we first realize ( Figure 9A ) a passivation zone made of insulating material 32 on peripheral portions 22a, 22b of at least one face, in particular the front face, of a solar cell 10 1.

[0075] We then assemble ( Figure 9B ) this cell 10 1 with other cells in order to constitute a chain 20A of cells, each of the cells 10 1 , 10 2 , 10 3 , 10 4 , 10 5 of this chain being preferably coated with passivation zones made of insulating material 32 on peripheral portions 22a, 22b.

[0076] The chain of cells thus formed is provided with lateral portions with an insulating region 31 here formed by all of the individual passivation zones of the cells of the chain.

[0077] Then, the assembly between chains of cells is carried out by performing a lateral overlap as described previously.

[0078] Afterwards ( Figure 9C ), connecting the cells within each chain and interconnection zones 51A, 51B in neighboring chains.

[0079] In either of the embodiments described above, all of the cell chains are distributed in such a way that the cell chains are typically of the same length and arranged parallel to each other, with their respective ends therefore aligned. This is the case, for example, on the Figure 7C .

[0080] Alternatively, we can provide as in the figure 10, an offset Δ between the respective ends 29A, 29B of adjacent chains 20A, 20B of cells. Such an offset can be envisaged in particular when an overlap of the cells is provided within the same chain. In this case, the formation of crossing points in four distinct cells and having, at these singular points, four cell thicknesses are avoided. According to a particular embodiment of such a variant, a staggered distribution of the ends of the chains of cells can be provided.

[0081] An offset typically between 1 mm and a length of the order of half the cell size can be expected.

[0082] The particular arrangement described above of laterally overlapping strings has been illustrated previously in combination with a particular arrangement of cells within a string of cells in which the cells overlap each other two by two, for example in a paving or shingle arrangement.

[0083] However, the adjacent chains with lateral overflow may alternatively be chains in which a conventional arrangement of cells is provided. Thus, the lateral overlap of the chains of cells can also be implemented with a succession of cells arranged one after the other without overlapping of the cells between them within the same chain.

[0084] The lateral overlap of cell chains described above applies to different cell types, for example also to interdigitated back contact (IBC) cells.

[0085] Lateral overlapping of chains also applies to different cell chain manufacturing technologies, for example also to that implementing a particular SWCT™ type interconnection.

[0086] A solar module with lateral overlap of cell strings as described above has various applications. For example, it can be integrated into a solar farm or a roof terrace, into a solar vehicle, or even find applications in the space sector.

Claims

1. Photovoltaic device comprising an assembly of several strings (20A, 20B, 20C, 20D, 20E, 20F) of photovoltaic cells (101,...,10 12), each of said chains being formed of a plurality of photovoltaic cells aligned in a first direction (y), said chains being aligned in a second direction (x) making a non-zero angle with the first direction and typically orthogonal or substantially orthogonal to the first direction, said assembly comprising at least a first chain (20A) laterally overlapped by a second chain (20B) of said plurality of chains, so that a peripheral portion (22') of said second chain covers a peripheral portion of said first chain, said first chain (20A) and said second chain (20B) being electrically insulated by means of an insulating region (31) interposed between said respective peripheral portions of the first chain and the second chain.

2. A photovoltaic device according to claim 1, wherein said second string (20B) of cells is juxtaposed and laterally overlaps or is laterally overlapped by a third string (20C) of cells.

3. Photovoltaic device according to one of claims 1 or 2, wherein in said first string (20A) of cells is coated with one or more first conductive track(s) (12a) which extend(s) parallel or substantially parallel to the first direction (y), said second string of cells being coated with one or more second conductive track(s) (12b) which extend(s) parallel or substantially parallel to the first direction (y), the first conductive track(s) (12a) being connected to the second conductive track(s) (12b via an electrically conductive interconnection zone (51) arranged on a first side of the assembly at a first end of said first string (20A) and at a first end of said second string (20B).

4. Photovoltaic device according to claim 3, wherein the second string (20B) of cells is juxtaposed and laterally overlaps or is laterally overlapped by a third string (20C) of cells, the third string of cells being coated with one or more third conductive track(s) (12) which extend(s) in particular parallel or substantially parallel to the first direction, the third string of cells being juxtaposed and laterally overlaps or is laterally overlapped by a fourth string (20D) of cells, said fourth string of cells being coated with one or more fourth conductive track(s) (12) which extend(s) in particular parallel or substantially parallel to the first direction, the first string (20A), the second string (20B), the third string (20C),the fourth chain (20D) having a first end located on the first side of the assembly and a second end located on a second side of the assembly opposite said first side of the assembly, the third conductive track(s) being electrically connected to said fourth conductive track(s) via another electrically conductive interconnection zone (51) arranged on said second side of the assembly., 5. Photovoltaic device according to one of claims 3 or 4, in which the first end and the second end of the first string (20A) are offset relative to, respectively, the first end and the second end of the second string (20B).

6. Photovoltaic device according to one of claims 1 to 5, wherein said cells are of the pseudo-square type, with beveled edges (2c), the cells of the first chain (20A) overlapping so that a longitudinal edge (2a) of a first cell (101) is arranged opposite said beveled edges of a second cell (10z) adjacent to said first cell (101).

7. Photovoltaic device according to one of claims 1 to 6, wherein the insulating region (31) is made of or comprises a material (32) having adhesive properties.

8. Photovoltaic device according to one of claims 1 to 6, the insulating region (31) being formed from a material (32) transparent to photons at a wavelength between 200 nm and 1200 nm, advantageously between 400 and 800 nm.

9. Photovoltaic device according to one of claims 1 to 8, the insulating region (31) being formed from a thermoplastic or thermosetting material.

10. Photovoltaic device according to one of claims 1 to 9, the insulating region being formed from a material (32) having a dielectric strength of between 15 and 30 V.

11. A method of manufacturing a photovoltaic device according to one of claims 1 to 10, comprising the following steps: - assembling a set of photovoltaic cells (101, 102, 103, 104, 105, 106) so as to form at least the first string (20A) of cells and passivating opposite peripheral portions (22a, 22b) of the cells of said set of cells and located along lateral edges of said cells, to form said insulating region (31), then, - assembling the first string (20A) of cells and the second string (20B) of cells by making the lateral overlap of the second string on the first string of cells, the second string of cells being arranged in contact with said insulating region (31).

12. Method according to claim 11, wherein the passivation of the peripheral portions (22a, 22b) is carried out after a step of assembling cells to form said first chain of cells.

13. Method according to one of claims 11 or 12, further comprising the formation of conductive tracks on said first chain (20A) and at least one conductive zone (51) for interconnection with conductive tracks of a second chain of cells adjacent to the first chain (20A), said conductive interconnection zone (51) being produced after said passivation.