IMPROVED INTERCONNECTION AND ASSEMBLY STRUCTURE OF OVERLAPPING SOLAR CELLS

Abstract

Solar cell assembly provided with a connection structure (40) arranged opposite and between a peripheral zone of a first solar cell and a second peripheral zone of a second solar cell, said connection structure providing increased mechanical flexibility and comprising: - an oblong conductive portion (41), - a set of conductive blocks (42, 43) distributed over said oblong conductive portion, alternately over a first region (41A) of oblong conductive portion (41) and over a second region (41B) of said oblong conductive portion (41) opposite said first region (41A). Figure for abstract: figure 3.

Description

Title of the invention: IMPROVED INTERCONNECTION AND ASSEMBLY STRUCTURE OF OVERLAPPING SOLAR CELLS Technical field

[0001] The present application relates to the field of photovoltaic (PV) cells, also called solar cells, and more particularly to that of their assembly and interconnection.

[0002] It relates to an assembly of solar cells provided with a particular interconnection structure, to the production of such an assembly as well as to a photovoltaic module comprising such an assembly. STATE OF THE PRIOR ART

[0003] A conventional technique for interconnecting solar cells is based on the use of an electrically conductive metal ribbon which provides the electrical connection between one cell and the next cell.

[0004] Such a type of interconnection is illustrated in [Fig. 1 A] in the particular case of cells 11, 12, 13 with rear face contact (RCC), the metal strip 4 here connecting an electrode 3a arranged on the rear face 2B of a cell 1b, 12 and an electrode 3b arranged on the rear face of another cell 12, 13.

[0005] According to a variant, illustrated in [Fig. 1B], the metal strip 4 here connects an electrode 3a arranged on the front face 2A of a cell 1b and an electrode 3b arranged on the rear face 2B of another cell 12.

[0006] In this case, the cells are generally arranged next to each other and this results in a surface 5 which is lost between the cells, which increases the size of the assembly and which is consequently referred to as a “dead zone”.

[0007] Another assembly technique called "Shingle" (in French tiling), makes it possible to limit the size and consists of superimposing the edges of cells 1b 12, on a small surface. The interconnection between a conductive zone 7 on the front face 2A of a cell 11 and a conductive zone 8 on the rear face 2B of another cell 12 is then carried out by means of a conductive material 9, of the solder material type added at the level of an overlap zone between the cells or conductive glue of the ECA type (for Electro Conductive Adhesive) based on Acrylate or Epoxy. This interconnection structure has the advantage of not creating a dead zone between cells 11, 12. However, it results in a rigid mechanical structure which can be fragile when it undergoes significant thermomechanical stresses.

[0008] The document "Materials Challenge for shingled cells interconnection" by Beaucarne et al., 6th workshop on metallization and interconnection for crystalline Silicon solar cells, 2016, proposes a Shingle-type assembly using an ECA type glue (ECA for "Electrically Conductive Adhesive") with a silicone base (more mechanically flexible than acrylate or Epoxy) in order to make the final assembly more flexible. However, such a structure allows little deformation in the plane of the cells.

[0009] The problem arises of finding a new interconnection technique which is improved in view of the drawbacks stated above. Statement of the invention

[0010] One embodiment provides a solar cell assembly comprising: - a first solar cell connected to a second solar cell, the second solar cell being arranged such that a peripheral area of ​​a rear face of the first cell called "first peripheral area" overlaps a peripheral area of ​​the front face of the second cell called "second peripheral area", the assembly further comprising:

[0011] - a connection structure arranged opposite and between said first zone peripheral and said second peripheral zone,

[0012] said connection structure being formed:

[0013] - at least one oblong conductive portion,

[0014] - a succession of conductive blocks arranged against and in contact with said oblong conductive portion and in an overlapping zone between said first peripheral zone and said peripheral zone, said conductive blocks being alternately distributed on a first region (typically a first face) of oblong conductive portion and on a second region (typically a second face opposite the first face) of said oblong conductive portion opposite said first region, one or more first blocks among said first conductive blocks being in contact with said first peripheral zone, one or more second conductive blocks being in contact with said second peripheral zone.

[0015] Such a structure makes it possible to achieve mechanical decoupling between the cells and to give the assembly increased flexibility which makes it more resistant to thermomechanical stresses.

[0016] Preferably, the set of said one or more second conductive blocks is offset relative to the set of said one or more first conductive blocks, which allows better deformation in a plane parallel to the cells and contributes to making the assembly more flexible and therefore resistant to certain thermomechanical stresses.

[0017] Advantageously, one or more or each of said one or more first conductive blocks may be opposite an empty space and / or an area of ​​insulating material disposed between said second region of said oblong conductive portion and said second peripheral area.

[0018] Advantageously, one or more second conductive blocks or each of the second conductive blocks may be arranged opposite an empty space and / or an area of ​​insulating material arranged between said first region of said oblong conductive portion and said first peripheral area.

[0019] According to one possible implementation, this insulating material may be a polymer material. Such a type of material has the advantage of having a low Young's modulus, which promotes the flexibility of the assembly.

[0020] According to a particular embodiment, at least one of said one or more first conductive blocks may be surrounded by an insulating passivation zone arranged between said first oblong conductive portion region and said first peripheral zone of the first cell.

[0021] According to a particular embodiment, at least one of said one or more second conductive blocks may be surrounded by an insulating passivation zone arranged between said second region of said oblong conductive portion and said first peripheral zone of the first cell.

[0022] The oblong conductive portion may advantageously be in the form of at least one conductive wire, or of several separate juxtaposed conductive wires or even of a conductive strip, in particular a flat strip.

[0023] A particular embodiment provides said conductive blocks in the form of conductive glue dots, in particular a glue made of polymer material loaded with conductive particles, such as an ECA type glue. In this case, the flexibility of the assembly can be promoted.

[0024] Alternatively, said conductive blocks may be areas of solder material. In this case, a connection structure having a lower electrical contact resistance can be obtained.

[0025] According to a particular embodiment, said conductive blocks have a substantially rectangular or substantially parallelepiped shape with rounded corners. Such a shape of the conductive blocks can also make it possible to obtain increased flexibility of the structure.

[0026] According to another aspect, the invention relates to a solar module provided with an assembly as defined above.

[0027] According to another aspect, the invention relates to a method of producing an assembly as defined above. Brief description of the drawings

[0028] The present invention will be better understood on reading the description of exemplary embodiments given, for purely indicative and non-limiting purposes, with reference to the appended drawings in which:

[0029] [Fig.lA]

[0030] [Fig. 1B] serve to illustrate a conventional technique for assembling and interconnecting solar cells using a conductive tape;

[0031] [Fig.2] serves to illustrate another assembly and interconnection technique of solar cells according to the prior art, in which the solar cells overlap and are connected by means of a solder material or an ECA material;

[0032] [Fig.3]

[0033] [Fig.4]

[0034] [Fig.5]

[0035] [Fig.6] are used to illustrate a solar cell interconnection and assembly structure according to an embodiment of the present invention, the assembly being carried out without dead zones and having increased flexibility;

[0036] [Fig.7] serves to illustrate the behavior of the interconnection structure when it undergoes thermal and / or mechanical stress;

[0037] [Fig.8] serve to illustrate differences in performance in terms of average energy density accumulated in a connection structure according to the invention compared to a conventional connection structure;

[0038] [Fig.9A]

[0039] [Fig.9B] are used to illustrate different densities of contact conductor blocks in a solar cell interconnection structure as implemented according to the invention;

[0040] [Fig. 10] serves to illustrate differences in electrical performance between an interconnect structure and an interconnect structure as implemented according to the present invention;

[0041] [Fig. 11]

[0042] [Fig. 12]

[0043] [Fig. 13]

[0044] [Fig. 14] are used to illustrate an alternative solar cell interconnection structure with several separate parallel conductive wires;

[0045] [Fig. 15]

[0046] [Fig. 16] serve to illustrate another alternative solar cell interconnection structure;

[0047] [Fig.l7A]

[0048] [Fig.l7B]

[0049] [Fig.l7C]

[0050] [Fig. 17D] serve to illustrate steps of an exemplary method of assembling and interconnecting solar cells as implemented according to an embodiment of the present invention;

[0051] [Fig. 18 A]

[0052] [Fig.l8B]

[0053] [Fig.l8C]

[0054] [Fig. 18D] serve to illustrate another example of a method of assembling and interconnecting solar cells as implemented according to an embodiment of the present invention;

[0055] Identical, similar or equivalent parts of the different figures bear the same numerical references so as to facilitate the transition from one figure to another.

[0056] The different parts represented in the figures are not necessarily on a uniform scale, in order to make the figures more readable.

[0057] Furthermore, in the following description, terms which depend on the orientation of the structure such as "front", "upper", "rear", "lower", "lateral", "central", "peripheral" apply considering that the structure is oriented in the manner illustrated in the figures.

[0058] DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

[0059] Reference is now made to [Fig. 3] showing (by means of an exploded view) an assembly of solar cells 10i, 102 as implemented according to an embodiment of the present invention.

[0060] The solar cells 10i, 102 are formed from a semiconductor substrate, which may be polycrystalline or monocrystalline and in particular based on polycrystalline or monocrystalline silicon. Each of the cells 10i, 102 is provided with at least one face 2A called the “front face”, which receives light and is intended to be exposed to solar radiation, and a face 2B called the “rear face”, opposite the front face 2A. The rear face 2B may optionally also be intended to be exposed to solar radiation. In this particular case, the cell is called “bifacial”.

[0061] At least one first solar cell 10i of this assembly is provided with contacts distributed on the rear face 2B, including one or more contacts (not shown) with respectively one or more N-type doped zones (in other words having a doping producing an excess of electrons) and one or more contacts (not shown in this figure) with respectively one or more P-type doped zones. (in other words according to a doping consisting of producing a deficit of electrons), the N-type zone(s) associated with the P-type zone(s) forming at least one junction.

[0062] The assembly is such that a peripheral zone 23B located on the rear face 2B of the first cell 10i is arranged opposite a peripheral zone 22A of the front face 2A of a second cell 102.

[0063] The solar cells 10i, 102 are thus assembled here according to an assembly of the type called “shingle”, in other words so as to partially overlap, which in particular makes it possible to achieve a compact assembly. The overlap can be provided over a distance typically of at least 0.2 mm and which can be, for example, between 0.5 mm and several millimeters.

[0064] In addition to the assembly, the connection of the cells 10i, 102 to each other is carried out here using a particular connection structure 40 which is arranged between the cells 10i, 102, and is preferably confined at a region where they overlap.

[0065] This connection structure 40 is formed of an oblong conductive portion 41 which, in the particular embodiment illustrated in [Fig. 3], is in the form of a conductive strip. On and in contact with the external surface of this oblong conductive portion 41, projecting conductive blocks 42, 43 are provided to be brought into contact respectively with the solar cells 10i, 102 and to allow an electrical connection to be ensured from one cell to the other.

[0066] The conductive blocks 42, 43 are distributed alternately over a first region 41A of said conductive portion 41 placed opposite the peripheral zone 23B of the first cell 10i and over a second region 41B, opposite the first region, of said conductive portion 41, the second region being arranged opposite the peripheral zone 22A of the second cell 102. In the case where the oblong conductive portion 41 is in the form of a conductive strip of planar shape, the first region 41A and the second region 41B are respectively a first face 41A and a second face 41B opposite the first face 41A.

[0067] The connection structure 40 thus comprises one or more first conductive blocks 42 on the first face 41A and one or more second conductive blocks 43 on the face 41B opposite the first face 41A.

[0068] Confining the connection structure 40 and the conductive blocks 42, 43 at the level of the overlapping region of the cells 10i, 102 makes it possible not to obstruct parts, including the rear face 2B, which one might want to expose to solar radiation.

[0069] In order to provide flexibility to the assembly, the blocks 42, 43 are here distributed along an axis AA', alternately on the first face 41A and on the second face 41B, with, preferably, an offset provided from one conductive block 42 to the other 43. along this axis AA'. The entire block(s) 42 formed on the first face 41A is thus offset from the entire block(s) 43 located on the second face 41B.

[0070] Thus, in the succession of conductive blocks 42, 43, along the axis AA' each conductive block 43 is offset from the following block 42.

[0071] Thus, as shown in Figures 4, 5, 6 (giving sectional views of the assembly respectively along an axis AA', an axis BB', an axis CC' given in [Fig. 3]), the conductive blocks 42 and the conductive blocks 43 are misaligned so that a conductive block 42 located on the first face 41A of the conductive strip 41 and in contact with the first cell 10i is not arranged opposite or entirely opposite a second conductive block 43 of the second face 41B but rather at least one space 36 provided between the second face 41B and the second cell 102. Similarly, a conductive block 43 located on the second face 41B of the conductive strip 41 and in contact with the second cell 102 is not arranged opposite or entirely opposite a first conductive block 42 located on the first face 41A but of at least one space 38 provided between the second face 41B and the first cell 10i.

[0072] This arrangement implies that the electrical connection between the two cells 10i and 102 is not established along a vertical conduction path (axis parallel to the vector z of the orthogonal reference frame [O; x; y; z]), but along an 'S' path. Such an arrangement makes it possible to promote mechanical decoupling between the cells 10i, 102 and allows deformation of the cells 10i, 102 following thermomechanical stress or following manipulation of the assembly of cells 10i, 102.

[0073] The oblong conductive portion 41, when in the form of a strip, may be provided with a width W (smallest dimension measured in a plane parallel to the cells and to the plane [O; x; y]) of, for example, between 0.1 and several millimeters, and advantageously between 0.2 mm and 1 mm. Typically, the width W of the strip corresponds to the overlap width between the cells 10i, 102, for example of the order of 1 mm. The strip may also be provided with a thickness e (dimension measured parallel to the z axis) of, for example, between 10 μm and 500 μm, for example of the order of 50 μm. The strip may optionally extend over the entire length of a cell.

[0074] The conductive blocks 42, 43 may be provided with a thickness of, for example, between 5 μm and 200 μm, for example of the order of 50 μm. This thickness is adapted in particular as a function of the number of blocks, their surface area and their distribution pitch on the oblong conductive portion 41.

[0075] As regards the composition of the structure, the oblong conductive portion 41 may be formed from one or more metallic material(s) such as, for example, copper or silver or tinned copper. A particular embodiment provides a conductive portion 41 formed from a core of conductive material, in particular a metallic material such as copper or silver, coated with areas of insulating material forming a discontinuous insulating sheath around the conductive blocks. The insulating material may be a polymer, for example a polyimide such as Kapton™.

[0076] The conductive blocks 42, 43 are typically made of a material different from that of the oblong conductive portion 41 and may in particular be attached to this oblong conductive portion 41 typically in the form of conductive glue dots or areas of solder material.

[0077] For example, when the conductive blocks 42, 43 are brazing areas, they may be formed from a tin-silver-copper (SnAgCu, also known as SAC) metal alloy which is a lead-free alloy. In particular, an alloy of the "SAC305" type composed of more than 95% tin, of the order of 3.0% silver and of the order of 0.5% copper may be used.

[0078] When the conductive blocks 42, 43 are conductive glue points, an ECA (for “Electrically Conductive Adhesive”) glue can be used. Such an adhesive is formed from a polymer matrix, typically of the epoxy, acrylate or silicone type, loaded with conductive particles. For example, a silver epoxy glue of the EPO-TEK® H20E, Loctite® 8282 or Loctite® 8311 type can be used in particular.

[0079] Thus, with such a connection structure 40, the conductive blocks 42, 43 ensure both mechanical and electrical contact on the cells 10i, 102, while the oblong portion 41 makes it possible to ensure mechanical decoupling between the cells and for the assembly to resist thermal and / or mechanical stresses.

[0080] As shown in [Fig.7], such decoupling can allow the connection structure 40 (shown in top view) to deform when it is subjected to thermal and / or mechanical stress, without however damaging the cells, the latter being typically made of a material having significant rigidity such as silicon.

[0081] In the embodiment illustrated in Figures 3, 4, 5, 6, empty spaces 38, 36 are provided between the connection structure and the cells 10i, 102. Alternatively and as suggested previously, these spaces may be at least partially filled by at least one insulating passivation material, for example a material with a low Young's modulus, in particular a polymer such as, for example, Kapton™.

[0082] Numerical stress simulations using the Ansys® tool were carried out to enable a connection structure as described above to be compared with a conventional connection structure using implements a simple conductive strip between two overlapping cells. Results of such a simulation are given by the graph in [Fig.8].

[0083] For the conventional structure, the interconnection consists of a continuous bead of ECA type glue 50 pm thick and 156 mm long, corresponding to an M2 format of solar cells. The glue material is considered to have a Young's modulus of 1000 μm.

[0084] At the same time, a connection structure as implemented according to the invention is considered, with at least three conductive blocks (two on one face, one on another face) on a conductive copper strip of length 156 mm with a Young's modulus for copper of 124 GPa.

[0085] The number of conductive blocks is varied from 3 to 50 to assess the evolution of the deformation capacities of the structure according to the invention.

[0086] For each of the established simulation models, an arbitrary deformation of 1 pm is applied.

[0087] Since the simulated geometries and materials are not identical between the two structures, mechanical stress levels are not compared. The output data chosen for comparison here is an average elastic energy density accumulated in the complete interconnection following a deformation of 1 pm. This data can be likened to the inverse of mechanical flexibility. The results are represented by the C40 curve normalized with respect to the conventional interconnection (Cconv).

[0088] On the one hand, it is observed that the average density of elastic energy accumulated in the connection structure according to the invention always has a lower value than the reference structure. As regards the influence of the number of conductive protuberances, even considering 50 protuberances (which, in the present case, is equivalent to one electrical connection point every 1.5 mm), the level of accumulated energy is 5 times lower than that present in the case of a conventional connection structure.

[0089] Figures 9A and 9B show the cells 10i, 102 before assembly, with different densities of conductive blocks 42, 43 at the areas 23B, 22A.

[0090] [Fig.9A] illustrates a first case of a small number n of conductive blocks, for example equal to 3, along each cell. In this case, in order to distribute the current in all the conductive fingers 47 on the cell surface, it is possible to provide a greater thickness of the conductive zones 46 on which they are in contact and which are produced for example by screen printing with silver paste.

[0091] In a second case ([Fig.9B]) of a large number of conductive blocks along the cells to be connected (n=50), the conductive zone 46 can be provided with a thickness of a conventional Shingle assembly.

[0092] The geometric optimum of the connection structure and in particular the number, size and density of the conductive blocks 42, 43 depends on a compromise between necessary mechanical flexibility while guaranteeing sufficient electrical performance of the interconnection.

[0093] [Fig. 10] illustrates the result of a comparison between the series resistance of a first connection structure according to the invention (curve Ci) and that of a second connection structure according to the invention (curve C2).

[0094] The first connection structure according to the invention (curve Ci) is here formed of a copper strip with dimensions thickness*length*width of 0.05*156*1mm and conductive blocks projecting from the strip and formed of a brazing material of type SAC305. The brazing zones have dimensions of 0.05*1*1mm (thickness*length*width).

[0095] The series resistance of a second interconnection as implemented according to the invention with ECA type glue dots is also illustrated (curve C2).

[0096] The comparison is carried out using an analytical calculation (R=(Rho*L) / S), with R the electrical resistance of the material, Rho the resistivity of the material, L the length and S its section, considering resistivities for Copper of 17e-9 ohm.m, for SAC305 brazing: 1.3e-6 ohm.m, for ECA glue of 4e-2 ohm.m.

[0097] The results presented in the form of curves Ci, C2 as a function of the number n of glue points or soldering zones along the overlap zone between cells.

[0098] The structure according to the invention makes it possible to use a solder-type material for the connections on the cells. It is observed in fact that the interconnection proposed in this invention always has a theoretical electrical resistance lower than that of a conventional structure.

[0099] Another example of an interconnection structure between cells 10i, 102 is given in FIGS. 11 to 14, giving respectively an exploded view, a sectional view AA', a cross-sectional view BB', and another sectional view CC' along another cross-sectional plane). The oblong portion of the connection structure this time takes the form of conductive wires 81, 91 juxtaposed and preferably arranged one parallel to the other.

[0100] The conductive blocks 42, 43 (not shown in [Fig. 1 1] for the sake of simplification) distributed respectively on the conductive wires 81, 91 and under the conductive wires 81, 91 may have an arrangement similar to that described previously. The structure here comprises passivation zones 54, 55 distributed respectively on the conductive wires 81, 91, and under the conductive wires 81, 91. Thus, one or more passivation zones 54 are arranged between the first cell 101 and an upper face of the conductive wires 81, 91, while one or more other passivation zones 55 are arranged between the second cell 102 and a lower face of the conductive wires 81, 91 opposite the upper face. Each passivation zone 54 (resp. 55) may be provided between two conductive blocks 42 (resp. 43).

[0101] The passivation zones 54, 55 may be in the form of a film or a layer of insulating material, for example a polymer material such as Kapton™, and transparent in the case where the film is wider than the overlapping area of ​​the cells and which is attached to the conductive wires 81, 91.

[0102] As can be seen in Figures 13 and 14, the thickness of the passivation zones can be less than that of the conductive blocks 42, 43. An empty space 56 (resp. 58) can thus be provided between a passivation zone 55 (resp. 54) and the cell 102 (resp. 102) opposite which this passivation zone is located.

[0103] An alternative embodiment with this time a single conductive wire 81 to make the connection between conductive blocks 42 connected to the cell 101 and conductive blocks 42 connected to the cell 101 is given in the cross-sectional views of figures 15 and 16.

[0104] The conductive wire 81a in the illustrated example has a parallelepiped shape. A cylindrical wire can also be used.

[0105] As regards its manufacture, a connection structure 40 as described previously can be produced in several ways.

[0106] A first possibility consists of functionalizing the oblong portion 41 and then carrying out the assembly with the cells. Thus, the conductive blocks 42, 43 are formed on the oblong portion 41, for example on an upper face and on a lower face of a conductive strip, then the interconnection structure is arranged so that it is interposed in the overlapping zone between the cells 10i, 102. The assembly is then carried out.

[0107] For example, one can start from a conductive strip on which one or more conductive blocks are made, for example in the form of conductive glue dots on a first face. The conductive blocks can be made, for example, by screen printing using a masking, possibly temporary, arranged on the first face and comprising one or more openings revealing the first face of the conductive strip.

[0108] Then, one or more conductive blocks are formed on a second face, for example conductive glue dots on a second face opposite the first face. Similarly, conductive blocks can be produced on the second face, for example by screen printing, using for example the same masking or another masking, possibly temporary, arranged on the second face and comprising one or more openings revealing the second face of the conductive strip.

[0109] A variant illustrated in Figures 17A-17D, provides for producing passivation zones 55, for example in polymer on one face or on one side of the oblong portion ([Fig.l7A]), here formed of juxtaposed conductive wires 81, 91, and other passivation zones 54 on the opposite face or on the opposite side. Then, the structure thus obtained is assembled with a cell 102 on which conductive blocks 43 in the form of glue dots or solder zones are arranged ([Fig.l7C]). Then, other conductive blocks 42 can be added in the form of glue dots or solder zones on the other cell 10 which is then assembled with the structure previously obtained ([Fig.l7D]).

[0110] As a variant of this step, the other conductive blocks can be added in the form of glue dots or solder zones on the conductive wires 81, 91 and the assembly with the other cell is then carried out.

[0111] According to another variant illustrated in Figures 18A-18D, it is possible to first provide for producing one or more conductive blocks 43, for example glue or solder points on a peripheral zone of a solar cell 102 ([Fig.l8A]). Then, the oblong conductive portion 41 is placed on these conductive blocks 43 ([Fig.l8B]).

[0112] Then ([Fig.l8C]), we form in another set of conductive blocks 42 on the oblong conductive portion for example glue or solder points. Then ([Fig.l8D]) we place the other cell 10i on this other set of blocks 42.

[0113] Such a variant is particularly suitable when the blocks are in the form of solder drops (soldering paste).

[0114] According to another variant, one or more conductive blocks can also be produced on each cell and then each cell equipped with the conductive blocks can be attached to one of the faces of the conductive strip.

[0115] A particular embodiment provides for distributing the material of the conductive blocks simultaneously at several points on the conductive strip, for example by means of a plurality of dispensing needles delivering drops of glue, in particular an ECA glue.

Claims

Claims

1. A method of producing a solar cell assembly, said assembly comprising a first cell (10i) connected to a second cell (102), said second cell being arranged so that a peripheral zone (23B) of a rear face (2B) of the first cell, called the "first peripheral zone", overlaps a peripheral zone (22A) of the front face (2A) of the second cell, called the "second peripheral zone", the method comprising steps of: - producing a connection structure (40) formed: of at least one oblong conductive portion (41), and of a succession of conductive blocks (42, 43), said conductive blocks (42, 43) projecting from the oblong portion and being conductive glue points, said conductive blocks being arranged alternately on a first region (41A) of the oblong conductive portion (41, 81,91) and on a second region (41 B) of said oblong conductive portion (41) opposite said first region (41A), then, - assembling the connection structure with the first cell and the second cell, the connection structure being arranged opposite and between said first peripheral zone (23B) and said second peripheral zone (22A), in an overlapping zone between said first peripheral zone and said peripheral zone, one or more first blocks (42) among said first conductive blocks being in contact with said first peripheral zone (23B), one or more second conductive blocks (43) being in contact with said second peripheral zone (22A), all of said one or more second conductive blocks (43) being offset relative to all of said one or more first conductive blocks (42).,

2. A method according to claim 1, wherein each of said one or more first conductive blocks (42) is arranged opposite an empty space (36) and / or an area of ​​insulating material disposed between said second region (41B) of said oblong conductive portion (41) and said second peripheral area (22A) and / or, wherein each of said one or more second conductive blocks (43) is arranged opposite an empty space (38) and / or an area of ​​insulating material (54) disposed between said first region (41A) of said oblong conductive portion (41) and said first peripheral zone (23B) of the first cell (10i).

3. The method of claim 2, wherein said insulating material is a polymeric material.

4. Method according to one of claims 1 to 3, at least one of said one or more first conductive blocks (42) being surrounded by an insulating passivation zone (55) arranged between said first region (41 A) of oblong conductive portion (41) and said first peripheral zone (23B).

5. Method according to one of claims 1 to 4, at least one of said one or more second conductive blocks (43) being surrounded by an insulating passivation zone (54) arranged between said second region (41B) of said oblong conductive portion (41) and said second peripheral zone (22A).

6. Method according to one of claims 1 to 5, in which said oblong conductive portion (41, 81, 91) is formed of at least one conductive wire (81), or of several distinct juxtaposed conductive wires (81, 91) or of a conductive strip (41).

7. A method according to one of claims 1 to 6, wherein said conductive blocks (42, 43) are provided with rounded corners.

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