EP4158693A1

EP4158693A1 - Photovoltaic chain and associated methods

Info

Publication number: EP4158693A1
Application number: EP21727486.9A
Authority: EP
Inventors: Armand Bettinelli
Original assignee: Commissariat a lEnergie Atomique CEA; Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Current assignee: Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Priority date: 2020-05-27
Filing date: 2021-05-26
Publication date: 2023-04-05
Also published as: FR3111030B1; FR3111030A1; US20230178669A1; WO2021239782A1

Abstract

An aspect of the invention relates to a photovoltaic chain (101) comprising a plurality of photovoltaic tiles (1, 2, 3', 3") and a metal connector (31); the tiles (1, 2, 3', 3") being glued together in pairs, forming a plurality of covering surfaces (V1, V2, V3), each covering surface (V1, V2, V3) having a covering width (Z1, Z2, Z3), the metal connector ( 31) being glued or welded to an end tile (1), forming a transfer surface (P1), the transfer surface (P1) having a transfer width (R1) greater than or equal to each of the covering widths (Z1), Z2, Z3), the active surface (Sa1) of the end tile preferably being greater than or equal to the active surface of an intermediate tile (Sa3', Sa3").

Description

DESCRIPTION

TITLE: Photovoltaic chain and associated processes

TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of chains of photovoltaic cells and in particular the connection of said chains to a metal connector.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

A photovoltaic chain is produced by the series interconnection of a plurality of photovoltaic cells forming a string of photovoltaic cells, each end of the string of photovoltaic cells being connected to a metal connector. Thus formed, the photovoltaic chain can be connected within an electrical network and supply electrical energy to the electrical network. The method commonly used for the formation of photovoltaic chains is the welding or gluing of ribbons or wires on collection electrodes on the front face of a first photovoltaic cell and on collection electrodes on the rear face of a second. adjacent photovoltaic cell. The first and second photovoltaic cells are separated by a few millimeters, approximately 3 mm, so that the ribbon or wire can change plan and pass from the front face of the first photovoltaic cell to the rear face of the second photovoltaic cell. The spacing between the photovoltaic cells increases the surface area of the photovoltaic chain thus formed.

There is a technique of interconnection of photovoltaic cells called "shingle" (translation of "shingle" or "tile" in English) which does not use ribbons or electric wires, making it possible to provide an answer to the problem. increase in the surface area of the photovoltaic chain. The “shingle” interconnection technique is for example described in the article [“Materials challenge for shingled cells interconnection”, G. Beaucarne, Energy Procedia 98, pp.115-124, 2016] The photovoltaic cells forming the photovoltaic garland are superimposed on top of each other, a lower PV cell being partially covered by an adjacent upper PV cell, in the same way that tiles cover a roof. The interconnection between two adjacent photovoltaic cells is made in the overlap area. The front face of the lower photovoltaic cell and the rear face of the upper photovoltaic cell each comprise an array of collection electrodes connected to an interconnection track, extending along one edge. During the interconnection of the photovoltaic garland, the two interconnection tracks are electrically and mechanically connected by welding or gluing. The interconnected shingle photovoltaic daisy chain thus eliminates the separation between the photovoltaic cells, offering a continuous active surface over the entire surface of the photovoltaic chain.

The photovoltaic garland is also electrically and mechanically connected to the metal connectors by transferring one of the metal connectors to each end photovoltaic cell of the photovoltaic garland. Current interconnection technologies, especially those that implement bonding using an electrically conductive adhesive, have made the interconnection between photovoltaic cells more reliable while reducing the overlap areas between two consecutive cells. The interconnections between cells are then able to withstand the stresses of seasonal thermal expansion.

On the other hand, the connections of the metal connectors with the end photovoltaic cells of the photovoltaic garland pose reliability problems.

SUMMARY OF THE INVENTION

[0006] The aim of the invention is to make the electrical and mechanical connection of the metal connectors more reliable within a photovoltaic chain.

A first aspect of the invention relates to a photovoltaic chain comprising: a first photovoltaic cell called the first end tile; a second photovoltaic cell called the second end tile; a plurality of third photovoltaic cells called intermediate tiles, arranged between the first and second end tiles; and a first metallic connector; each of the first, second and third photovoltaic cells comprising a front face and a rear face opposite the front face, the first end tile, the intermediate tiles and the second end tile being interconnected by means of a first adhesive electrically conductive, the first end tile being interconnected to a first intermediate tile, the rear face of the first end tile covering a surface of the front face of the first intermediate tile, called the first covering surface, the first covering surface having a first overlap width, the second end tile being interconnected with a second intermediate tile, the rear face of the second intermediate tile covering a surface of the front face of the second end tile, referred to as the second overlap surface, the second covering surface having a second covering width, the first metal connector ic being connected to the first end tile by means of a second electrically conductive adhesive, the first metal connector covering a surface of the front face of the first end tile, called the first transfer surface, the first transfer surface having a first carry width greater than each of the first and second lap widths.

[0008] Thus, the increase in the transfer width of the connectors makes it possible to make the mechanical, and therefore electrical, connection of the photovoltaic chain more reliable while retaining a unique adhesion technology, by bonding.

[0009] In addition to the characteristics which have just been mentioned in the previous paragraph, the photovoltaic chain according to the first aspect of the invention may have one or more additional characteristics among the following, considered individually or in any technically possible combination.

Advantageously, the intermediate tiles are interconnected two by two, for each intermediate tiles interconnected two by two, the rear face of a first intermediate tile covers the front face of a second intermediate tile, covering a surface of the second tile intermediate.

Preferably, the short-circuit current on the front face of the first end tile when the first transfer surface is masked is greater than or equal to the short-circuit current on the front face of an intermediate tile when its covering surface is masked.

Advantageously, the short-circuit current on the front face of the first end tile when its front face is fully exposed is greater than the short-circuit current on the front face of the intermediate tile when its front face is fully exposed .

Advantageously, the active surface on the front face of the first end tile is greater than or equal to the active surface on the front face of the intermediate tile.

Advantageously, the width of the first end tile is greater than the width of the intermediate tile.

Advantageously, the front face of the first end tile comprises a conductive interconnection track extending into the first transfer surface, the conductive interconnection track comprising a plurality of conductive patterns with closed contour spaced apart from one another. others, each closed-contour conductive pattern comprising a closed contour surrounding a portion of the front face, at least part of the closed-contour conductive patterns each containing a portion of the second electrically conductive adhesive adhering to the front face portion and to the first metal connector.

Advantageously, the conductive interconnection track comprises a conductive line electrically connecting two conductive patterns with consecutive closed contour.

Advantageously, the first metal connector comprises a plurality of disjoint portions, connected to the first end tile, each portion of the first metal connector covering a surface of the front face of the first end tile, said portion of the first transfer surface, each portion of the first transfer surface having a transfer width greater than each of the first and second cover widths.

Advantageously, the photovoltaic chain further comprises: a second metal connector; the second metal connector being connected to the second end tile by means of the second electrically conductive adhesive, the second metal connector covering a surface of the rear face of the second end tile, called the second transfer surface, the second surface of carryover having a second carryover width greater than each of the first and second carryover widths.

Advantageously, the short-circuit current on the rear face of the second end tile when the second transfer surface is masked is greater than or equal to the short-circuit current on the rear face of an intermediate tile when its surface overlap is hidden.

A second aspect of the invention relates to a method of manufacturing a photovoltaic chain comprising the following steps: providing a first photovoltaic cell called first end tile, a second photovoltaic cell called second end tile a plurality of third photovoltaic cells called intermediate tiles and a first metal connector, each of the first, second and third photovoltaic cells comprising a front face and a rear face opposite the front face; interconnecting the first end tile to a first intermediate tile by means of a first electrically conductive adhesive, the rear face of the first end tile covering a surface of the front face of the first intermediate tile, referred to as the first covering surface , the first overlap surface having a first overlap width; interconnecting a second intermediate tile to the second end tile by means of the first electrically conductive adhesive, the rear face of the second intermediate tile covering a surface of the front face of the second end tile, called the second covering surface, the second overlap surface having a second overlap width; connect the first metal connector to the first end tile by means of a second electrically conductive adhesive, the first metallic connector covering a surface of the front face of the first end tile, called the first transfer surface, the first transfer surface having a first transfer width greater than each of the first and second covering widths.

A third aspect of the invention relates to a photovoltaic chain comprising: a first photovoltaic cell called the first end tile; a second photovoltaic cell called the second end tile; a plurality of third photovoltaic cells called intermediate tiles, arranged between the first and second end tiles; and a first metallic connector; each of the first, second and third photovoltaic cells comprising a front face and a rear face opposite the front face, the first end tile, the intermediate tiles and the second end tile being interconnected by means of a first adhesive electrically conductive, the first end tile being interconnected to a first intermediate tile, the rear face of the first end tile covering a surface of the front face of the first intermediate tile, called the first covering surface, the first covering surface having a first overlap width, the second end tile being interconnected with a second intermediate tile, the rear face of the second intermediate tile covering a surface of the front face of the second end tile, referred to as the second overlap surface, the second covering surface having a second covering width, the first metal connector ic being connected to the first end tile, the first metal connector covering a surface of the front face of the first end tile, called the first transfer surface, the first metal connector being welded to the first end tile.

[0022] Welding thus makes it possible to limit the first and second transfer widths with respect to the connections by means of the second adhesive while making the connections within the photovoltaic chain more reliable. Maintaining a bond at the level of the interconnections of the intermediate tiles, which is more ductile than a weld, allows to absorb the deformations imposed by the expansion of the tiles. The reliability of the photovoltaic chain with regard to daily and seasonal expansions is thus improved.

[0023] In addition to the characteristics which have just been mentioned in the previous paragraph, the photovoltaic chain according to the third aspect of the invention may have one or more additional characteristics among the following, considered individually or in any technically possible combination.

Advantageously, the first transfer surface has a first transfer width substantially equal to the first and second cover widths.

Advantageously, the front face of the first end tile comprises a conductive interconnection track extending over the first transfer surface, the first metal connector being welded to the conductive interconnection track. Advantageously, the conductive interconnection track is continuous.

Advantageously, the conductive interconnection track comprises a plurality of disjoint portions, each portion being welded to the first metal connector.

Advantageously, the conductive interconnection track comprises a conductive line electrically connecting two consecutive portions of the conductive interconnection track.

Advantageously, the active surface on the front face of the first end tile is greater than or equal to the active surface on the front face of an intermediate tile. Advantageously, the first metal connector comprises a plurality of disjoint portions welded to the first end tile, each portion of the first metal connector covering a surface of the front face of the first end tile, called the first surface portion of postponement.

Advantageously, each portion of the first transfer surface has a transfer width greater than each of the first and second cover widths. Advantageously, the photovoltaic chain further comprises: a second metal connector; the second metal connector being welded to the second end tile, the second metal connector covering a surface of the rear face of the second end tile, called the second transfer surface, the second metal connector being welded to the second tile d 'end.

Advantageously, the second transfer surface having a second transfer width substantially equal to the second cover width.

A fourth aspect of the invention relates to a method of manufacturing a photovoltaic chain comprising the following steps: providing a first photovoltaic cell called the first end tile, a second photovoltaic cell called the second end tile, a plurality third photovoltaic cells called intermediate tiles, and a first metal connector, each of the first, second and third photovoltaic cells comprising a front face and a rear face opposite the front face; interconnecting the first end tile to a first intermediate tile by means of a first electrically conductive adhesive, the rear face of the first end tile covering a first surface of the front face of the first intermediate tile, referred to as the first surface of covering, the first covering surface having a first covering width; interconnecting a second intermediate tile to the second end tile by means of the first electrically conductive adhesive, the rear face of the second intermediate tile covering a surface of the front face of the second end tile, called the second covering surface, the second overlap surface having a second overlap width; welding the first metal connector to the first end tile, the first metal connector covering a surface of the front face of the first end tile, called the first transfer surface. A fifth aspect of the invention relates to a photovoltaic chain comprising: a first photovoltaic cell called the first end tile; a second photovoltaic cell called the second end tile; a plurality of third photovoltaic cells called intermediate tiles, arranged between the first and second end tiles; and a first metallic connector comprising a plurality of disjoint portions; each of the first, second and third photovoltaic cells comprising a front face and a rear face opposite the front face, the first end tile, the intermediate tiles and the second end tile being interconnected by means of a first adhesive electrically conductive, the first end tile being interconnected to a first intermediate tile, the rear face of the first end tile covering a surface of the front face of the first intermediate tile, called the first covering surface, the first covering surface having a first overlap width, the second end tile being interconnected with a second intermediate tile, the rear face of the second intermediate tile covering a surface of the front face of the second end tile, referred to as the second overlap surface, the second overlap surface having a second overlap width, each disjunct portion of the first metal connector being connected to the first end tile, each disjoint portion of the first metal connector covering a surface of the front face of the first end tile, called the portion of the first transfer surface, each portion of the first transfer surface having a carry width greater than each of the first and second lap widths.

The invention and its various applications will be better understood on reading the following description and on examining the accompanying figures.

BRIEF DESCRIPTION OF THE FIGURES

The figures are presented as an indication and in no way limit the invention. [0038] [Fig. 1] schematically shows, in side view and top view, a first embodiment of a photovoltaic chain according to the first aspect of the invention.

[0039] [Fig. 2] schematically shows, in bottom view, a second embodiment of the photovoltaic chain according to the first aspect of the invention.

[0040] [Fig. 3] schematically shows a first end tile of the photovoltaic chain according to a third embodiment, the first end tile being connected to a first metal connector.

[0041] [Fig. 4] schematically represents the first end tile of the photovoltaic chain according to the third embodiment, without the first metal connector.

[0042] [Fig. 5] schematically represents the first end tile of the photovoltaic chain according to the third embodiment, the figure being centered on two conductive patterns with closed contour. [0043] [Fig. 6] schematically represents the first end tile of the photovoltaic chain according to a fourth embodiment, the figure being centered on two conductive patterns with closed contour.

[0044] [Fig. 7] schematically represents the photovoltaic chain according to a fifth embodiment. [0045] [Fig. 8] schematically represents a manufacturing method according to the second aspect of the invention, of the photovoltaic chain according to the first aspect of the invention.

[0046] [Fig. 9] schematically shows in side view and top view, a first embodiment of a photovoltaic chain according to the third aspect of the invention.

[0047] [Fig. 10] schematically represents a second embodiment of the photovoltaic chain according to the third aspect of the invention, the figure being centered on a first end tile.

[0048] [Fig. 11] schematically shows a third embodiment of the photovoltaic chain according to the third aspect of the invention, the figure being centered on a first end tile. [0049] [Fig. 12] schematically represents a manufacturing method according to the fourth aspect of the invention, of the photovoltaic chain according to the third aspect of the invention.

DETAILED DESCRIPTION

The figures are presented as an indication and in no way limit the invention. Unless otherwise specified, the same element appearing in different figures has a single reference.

Glued photovoltaic chain

FIG. 1 schematically represents a first embodiment of a photovoltaic chain 101 according to a first aspect of the invention.

The photovoltaic chain 101 comprises: a first photovoltaic cell 1 called the first end tile; a second photovoltaic cell 2 called the second end tile; two third photovoltaic cells 3 ', 3 "called intermediate tiles; a first metal connector 31; and a second metal connector 32.

The photovoltaic chain 101 comprises two intermediate tiles 3 ', 3 ", however the photovoltaic chain 101 preferably comprises more than two intermediate tiles 3', 3", for example about thirty.

The first and second end tiles 1, 2 and the third intermediate photovoltaic tiles 3 ', 3 "are made from semiconductor substrates, for example made of silicon, making it possible to convert light radiation, for example solar, into electrical energy. The substrates implement so-called homojunction or heterojunction technologies. The surfaces of the tiles 1, 2, 3 ', 3 "preferably comprise an insulating layer, for example made of SiN, or a transparent conductive oxide layer, also called Transparent Conductive Oxide or TCO in English, for example indium-tin oxide.

The tiles 1, 2, 3 ', 3 "can have a square shape, for example of length 156 mm and width 156 mm, or preferably a rectangular shape, for example of length 156 mm and width 31, 2 mm or length 156 mm and width 26 mm. All the tiles 1, 2, 3 ', 3 "within a photovoltaic chain 101 preferably have the same shape and the same length W.

Each of the first and second end tiles 1, 2 and of the third intermediate photovoltaic tiles 3 ', 3 "comprises a front face and a rear face opposite the front face. The front face comprises: a conductive track of interconnection, and a plurality of collecting electrodes called "collecting fingers".

The collection fingers are intended to collect the electric currents produced by each photovoltaic cell 1, 2, 3 ', 3 ". The collection fingers extend parallel to each other along the front face and are preferably uniformly distributed over the front face. In order to transport the electric currents in the photovoltaic chain 101, the collection fingers are electrically connected to the conductive interconnection track. Each conductive interconnection track preferably extends parallel to an edge, in the vicinity from this edge, for example less than 1.5 mm from the edge or preferably less than 1.0 mm from the edge.

The rear face of each tile 1, 2, 3 ', 3 "further comprises one or more conductive elements also allowing the collection of electric currents. It may be a metallization covering the entire surface of the face. or else collecting fingers similar to the collecting fingers 5 of the front face The bifacial tiles, that is to say tiles capable of picking up electromagnetic radiation via the rear face, preferably comprise collection fingers.

The rear face of each tile 1, 2, 3 ', 3 "also comprises a conductive interconnection track allowing the interconnection of the tiles 1, 2, 3', 3" between them. It may for example be metallized tracks extending along an edge of the rear face, in the vicinity of this edge.

The first and second end tiles 1, 2 and the intermediate tiles 3 ', 3 "are interconnected in series, that is to say by electrically connecting the rear face of one of said tiles 1, 2, 3' , 3 "with the front face of a consecutive tile 1, 2, 3 ', 3". The intermediate tiles 3', 3 "are arranged between the first and second end tiles 1, 2. The interconnection between two consecutive tiles is made using a first electrically conductive adhesive. The first adhesive electrically conductive makes the electrical connection of consecutive tiles as well as the mechanical connection between said tiles.

The first end tile 1 is interconnected to a first intermediate tile 3 ', by electrically connecting the rear face of the first end tile 1 with the front face of the first intermediate tile 3'. The electrical connection is made without wire or tape, by connecting directly using the first electrically conductive adhesive the conductive interconnection track of the front face and the conductive interconnection track (or full plate metallization) of the rear face. According to this mode of interconnection called shingle in English, the rear face of the first end tile 1 covers a surface V1 of the front face of the first intermediate tile 3 ', called the first covering surface.

Because of the covering by the first end tile 1, the first covering surface V1 is not exposed to light radiation. In FIG. 1, the first covering surface V1 has a rectangular shape, extending along an edge covered with the first intermediate tile 3 ', preferably over the entire length of this edge. The first covering surface V1 extends over a first covering width Z1, measured perpendicular to said edge covered with the first intermediate tile 3 '.

Likewise, the second end tile 2 is interconnected with a second intermediate tile 3 ", by electrically connecting the front face of the second end tile 2 with the rear face of the second intermediate tile 3" . The electrical connection is also made by directly connecting by means of the first electrically conductive adhesive the conductive interconnection track of the front face and the conductive interconnection track (or the full plate metallization) of the rear face. The rear face of the second intermediate tile 3 "covers a surface V2 of the front face of the second end tile 2, called the second covering surface.

Like the first covering surface V1, the second covering surface V2 has a rectangular shape, extending along an edge covered with the second end tile 2 and preferably over the entire length of this covered edge. The second covering surface V2 extends over a second overlap width Z2, measured perpendicular to said covered edge of the second end tile 2.

The intermediate tiles 3 ', 3 "are interconnected with each other and are arranged between the first and second end tiles 1, 2. In Figure 1 where only two intermediate tiles 3', 3" are shown, the first intermediate tile 3 'is interconnected with the second intermediate tile 3 ", electrically connecting the rear face of the first intermediate tile 3' with the front face of the second intermediate tile 3". The electrical connection is also made by directly connecting the conductive interconnection tracks of each of the front and rear faces with the first electrically conductive adhesive. The rear face of the first intermediate tile 3 'covers a surface V3 of the front face of the second intermediate tile 3 ", called the third covering surface. The third covering surface V3 extends along a covered edge of the second intermediate tile 3 "and preferably over the entire length of this covered edge and over a third covering width Z3, measured perpendicular to said covered edge.

Preferably, the tiles 1, 2, 3 ', 3 "are aligned so that the covering surfaces V1, V2, V3 extend over the entire length of each tile 1, 2, 3', 3".

Preferably the first, second and third covering surfaces V1, V2, V3 are substantially equal. By "substantially equal" is meant areas where the difference does not exceed 5% (V1 = V2 ± 5% = V3 ± 5%). This difference corresponds, for example, to the alignment error of the tiles. The first, second and third covering surfaces V1, V2, V3 preferably extending over the entire length of the covered edges of the intermediate tiles 3 ', 3 "and of the second end tile 2, the first, second and third Coverage widths Z1, Z2, Z3 are preferably substantially equal (Z1 = Z2 ± 5% = Z3 ± 5%).

The photovoltaic chain 101 preferably comprises more than two intermediate tiles, for example more than thirty intermediate tiles. According to this variant, all the intermediate tiles are interconnected in series two by two. For each pair of interconnected intermediate tiles, the rear face of a first intermediate tile is electrically connected with the front face of a second intermediate tile using the first electrically conductive adhesive. The rear face of the first intermediate tile covers a surface V3 of the front face of the second intermediate tile, called the third covering surface. The series interconnection of a plurality of intermediate tiles thus forms a plurality of third covering surfaces V3. Each third covering surface V3 extends along a covered edge of each second intermediate tile and preferably over the entire length of this covered edge and over a third covering width Z3, measured perpendicular to said covered edge. Preferably, all of the third covering surfaces V3 are substantially equal and even more preferably, all of the third covering widths Z3 are substantially equal.

The mechanical reliability of the photovoltaic chain 101 strongly depends on the quality of the interconnection between each tiles 1, 2, 3 ', 3 ". The photovoltaic chain 101 undergoes, for example, successive expansions, due to daily variations and seasonal temperature The successive expansions stress the interconnections.

The first electrically conductive adhesive preferably comprises an organic material capable of crosslinking during a heat treatment of a few seconds to a few minutes at a temperature between 120 ° C and 200 ° C, such as epoxy, of acrylate or silicone. The organic material is loaded with a conductive material such as a powder of metallic or metallized particles on the surface. The copper-based metal particles are not chemically stable enough and are at least coated with a silver coating to stabilize them. Metal particles based on nickel or silver give the best performance.

The first electrically conductive adhesive advantageously comprises a rate of metallic or metallized particles of between 50% and 90%, in order to achieve a low resistive interconnection, in particular when the metallized elements of each tile 1, 2, 3 ', 3 " have low surface areas A metal particle content of between 50% and 60% provides sufficient electrical conductivity while keeping the cost of the adhesive low. The first electrically conductive adhesive is in particular more ductile than a weld, thus it makes it possible to absorb the deformations imposed by the expansion of the tiles 1, 2, 3 ', 3 ". The reliability of the photovoltaic chain 101 with regard to the daily and seasonal dilations is thus improved.

In order to provide the electric current due to the conversion of solar radiation within an electrical network, the end tiles 1, 2 and the intermediate tiles 3 ', 3 ", interconnected in series, are electrically connected to the first and second metal connectors 31, 32. The first and second metal connectors 31, 32 make it possible to easily connect the photovoltaic chain 101 in an electrical assembly.

The first and second metal connectors 31, 32 are respectively connected to the first and second end tiles 1, 2 by means of a second electrically conductive adhesive. The first metal connector 31 is connected to the front face of the first end tile 1. The first metal connector 31 covers a surface P1 of the front face of the first end tile 1, called the first transfer surface. The second metal connector 32 is connected to the rear face of the second end tile 2. The second metal connector 32 covers a surface P2 of the rear face of the second end tile 2, called the second transfer surface. The connections are preferably made by directly connecting the first and second connectors 31, 32 respectively to the conductive interconnection track of each of the first and second end tiles 1, 2 with the second electrically conductive adhesive.

The first and second transfer surfaces P1, P2 each have a rectangular shape. They extend over a length W respectively along an edge covered with the first end tile 1 and along an edge covered with the second end tile 2. The first transfer surface P1 has a first transfer width R1 measured perpendicular to said edge. The second transfer surface has a second width R2 measured perpendicular to said edge.

The second electrically conductive adhesive may be of the same nature as the first electrically conductive adhesive, that is to say comprise a resin and metallic or metallized particles. The second electrically conductive adhesive may be the same as the first electrically conductive adhesive. However, the second electrically conductive adhesive preferably comprises anti-corrosion agents allowing reliable contact with the metal connectors 31, 32, the latter generally being copper-based and coated with an alloy layer, for example tin. lead-silver. The first electrically conductive adhesive does not necessarily contain an anti-corrosion agent because the metallizations extending on the surfaces of the tiles 1, 2, 3 ', 3 ", containing for example silver, do not corrode. resin can be different in order to promote adhesion to metal surfaces. It can for example be more rigid because the need for ductility at the level of the tile / connector connection is less great than at the tile / tile level. The resin can be epoxy or acrylate based, exhibiting an adhesion to the substrate two to three times greater than the adhesion to a metallized zone.

On the other hand, unlike adhesion to the substrate, the second electrically conductive adhesive has limited adhesion to metal surfaces, such as the first and second metal connectors 31, 32. The connection of the first and second metal connectors 31, 32 therefore present a risk of detachment or tearing, called peeling in English.

In order to reduce the risk of detachment and thus make the adhesion of the first metal connector 31 to the first end tile 1 more reliable, the first transfer width R1 is greater than each of the first and second overlap widths Z1, Z2 and preferably also greater than each of the third cover widths Z3. Thus the contact width of the second electrically conductive adhesive between the first end tile 1 and the first metal connector 31 is increased.

Likewise, in order to make the adhesion of the second metal connector 32 to the second end tile 2 more reliable, the second transfer width R2 is advantageously greater than each of the first and second overlap widths Z1, Z2 and preferably also greater than each of the third cover widths Z3. For example, for overlap widths Z1, Z2, Z3 equal to 0.5 mm within the photovoltaic chain 101, the first and second transfer widths R1, R2 making it possible to connect the first and second metal connectors 31 , 32 are advantageously equal to 0.9 mm.

[0081] Thus, the increase in the transfer width of the connectors makes it possible to make the mechanical connection, and therefore electrical, of the photovoltaic chain 101 more reliable while retaining a unique adhesion technology, by bonding.

In order to reduce the risk of detachment and make the adhesion of the first metal connector 31 to the first end tile 1 more reliable, the first transfer surface P1 can be greater than each of the first and second covering surfaces V1, V2 , providing a larger bonding surface and thus improving adhesion.

The overlap widths Z1, Z2, Z3 and transfer R1, R2 are preferably less than 10 mm and still more preferably less than 3 mm and more preferably less than 1.5 mm.

Short-circuit currents and active surfaces

The short-circuit current on the front face of a photovoltaic cell is defined as the maximum current generated by said photovoltaic cell when its front face is oriented towards a source of illumination and its rear face is masked. The short-circuit currents on the front face of the end tiles 1, 2 and intermediate 3 ', 3 "determine the maximum current that the photovoltaic chain 101 can produce, including the front face of each tile 1, 2, 3', 3 "is exposed to a source of illumination 50. The end tiles 1, 2 and intermediate 3 ', 3" are electrically connected in series. Therefore, the maximum current of the photovoltaic chain 101 is limited by the tile producing the lower current.

The short-circuit current depends on several factors such as the conversion efficiency of the photovoltaic cell or the surface exposed to the source of illumination, which is called the active surface. The larger the active area, the greater the short-circuit current. The first and second end tiles 1, 2 and the first and second intermediate tiles 3 ', 3 "respectively have, on their front faces, first, second, third and fourth active surfaces Sa1, Sa2, Sa3', Sa3" . The first, second, third and fourth active surfaces Sa1, Sa2, Sa3 ′, Sa3 ″ occupy only a portion of each front face, reduced by the transfer surfaces P1 and overlap V1, V2, V3.

The first active surface Sa1 extends over the front face of the first end tile 1, over the entire length W of the tile 1 and over a first exposed width A1. When the first transfer surface P1 extends over the entire length of the first end tile 1, the first exposed width A1 is equal to the width of the first end tile L1 minus the first transfer width R1. In the same way: the second active surface Sa2 extends over the front face of the second end tile 2, over the entire length W of the tile 2 and over a second exposed width A2 equal to L2 - Z2. the third active surface Sa3 'extends over the front face of the first intermediate tile 3', over the entire length W of the tile 3 'and over a third exposed width A3' equal to L3 '- Z1. the fourth active surface Sa3 "extends over the front face of the second intermediate tile 3", over the entire length W of the tile 3 "and over a third exposed width A3" equal to L3 "- Z3.

Compared to the covering surfaces V1, V2, V3 of the other tiles 2, 3 ', 3 ", the first active surface Sa1 is reduced compared to the other active surfaces Sa2, Sa3', Sa3" by an equal area at P1 - max (V1, V2, V3). The short-circuit current of the first end tile 1 is therefore lower than the short-circuit currents of the other tiles 2, 3 ', 3 ", thus limiting the maximum current of the photovoltaic chain 101.

The invention proposes three technical solutions to prevent the first end tile 1 from limiting the maximum current of the photovoltaic chain. The three technical solutions increase the short-circuit current on the front face of the first end tile 1 when the first transfer surface P1 is masked so that it is greater than or equal to the lower of the short-circuit currents on the face. before the intermediate tiles 3 ', 3 "when their covering surfaces V1, V3 are masked. In this way, one of the intermediate tiles 3', 3" becomes the tile limiting the maximum current of the photovoltaic chain 101. It can be s' act from the first intermediate tile 3 ', from the second intermediate tile 3 "or from another tile intermediate. Since the intermediate tiles 3 ', 3 "are preferably selected to generate short-circuit currents on the front face that are substantially equal, ie to within 5%, the current generated by the photovoltaic chain 101 is nominal.

For this, according to a first variant, provision is made for the short-circuit current on the front face of the first end tile 1, when the front face is entirely exposed to the radiation source 50, is greater than the current. short-circuit on the front face of an intermediate tile 3 ', 3 "when its front face is fully exposed to the radiation source 50. The first end tile 1 can have a photoelectric conversion efficiency greater than the intermediate tile 3 ', 3 ", compensating for example the reduction of the first active surface Sa1 compared to the third and fourth surfaces Sa3', Sa3". In this way, when the first transfer surface P1 is masked by the first metal connector 31, the first end tile 1 does not limit the maximum current of the photovoltaic chain 101.

In order to maintain the same conversion yields for all the tiles 1, 2, 3 ', 3 ", a second variant embodiment of the photovoltaic chain 101 provides that the active surface Sa1 on the front face of the first tile of end 1 is greater than or equal to the active surface Sa3 ', Sa3 "on the front face of the intermediate tile 3', 3". In this way, with equal conversion efficiency, the short-circuit current on the front face generated by the first end tile 1 is at least equal to the current generated by the intermediate tile 3 ', 3 ".

In order to increase the first active surface Sa1, the width L1 of the first end tile 1 can be greater than the width L3 ', L3 "of the intermediate tile 3', 3". For example, if the carryover width R1 is fixed, then increasing the width L1 of the first tile makes it possible to increase the exposed width A1. Thus, if all the tiles 1, 2, 3 ', 3 "have the same length W, then the active surface Sa1 is greater than or equal to the active surface Sa3', Sa3" on the front face of the intermediate tile 3 ', 3 ". Tiles of identical length W facilitate the integration of the photovoltaic chain, which is why it is preferable to vary the width of the tiles. For example, the overlap widths Z1, Z2, Z3 can be equal to 0, 5 mm for tiles with widths L2, L3 ', L3 "of 26 mm and the first transfer width R1 may be equal to 0.9 mm for a first end tile of width L1 equal to 31.2 mm.

Discontinuous metal connector

In order to increase the active surface Sa1 of the front face of the first end tile 1, the length W of the first transfer surface P1 can be reduced while keeping the first transfer width R1 identical. For this, the first metal connector 31 extends along the covered edge of the first end tile 1, over a length W, as illustrated in FIG. 1. For example, the length W of the first transfer surface P1 can be equal to W / 2.

Reducing the length W of the first transfer surface P1 can also allow an increase in the first transfer width R1 in order to improve the reliability of the connection. For example, the length W may be less than W / 2 and the first carry width R1 may be greater than Z1 and less than twice Z1. Thus, the first transfer width R1 is increased, making the connection more reliable, while reducing the first transfer surface P1. The first active surface Sa1 is thus increased.

In order to provide a larger first active surface Sa1, one embodiment of the photovoltaic chain 101, illustrated by FIG. 7, provides for the first metal connector 31 to include a plurality of separate portions 31 ', 31 ". Each portion of the first metal connector 31 ', 31 "is connected to the front face of the first end tile 1, covering a portion of the first transfer surface P 1', P1". Each portion of the first transfer surface P1 ' , P1 ″ has a transfer width R1 ′, R1 ″, the two transfer widths R1 ′, R1 ″ preferably being equal to R1. In this way, the transfer widths R1 ′, R1 ″ can be increased while making it possible to reduce the surface area covered by the portions of the first transfer surface P1 ′, P1 ″. The transfer widths R1 ′, R1 ″ can be greater than each of the first and second cover widths Z1, Z2, making the connection more reliable while increasing the first active surface Sa1.

Each separate portion 31 ', 31 "of the first metal connector 31 also has a restricted width relative to the width W of the first end tile 1. Thus, during the thermal expansion of the photovoltaic chain 101, the overlap widths between copper and silicon being reduced, the Differential thermal expansion, also called the bimetal effect, is limited. Thus, the camber of the photovoltaic chain 101 is limited.

The first metal connector 31 comprises, for example, six disjoint portions 31 ', 31 "each having a length of 11 mm, occupying a total length W of 66 mm relative to the 156 mm of the first tile 1, or approximately 42% of 156 mm. The first metal connector 31 may alternatively comprise twelve disjoint portions 31 ', 31 "each having a length of 5 mm, occupying a total length W of 60 mm, ie approximately 38% of 156 mm.

The shading caused by the metallizations running through the front face between the portions 31 ’, 31” of the first metal connector 31 is advantageously taken into account in the calculation of the first active surface Sa1. The conductive interconnection track 4 is preferably located in the first transfer surface. In the case where the first metal connector 31 comprises several separate portions 31 ', 31 ", the interconnection track 4 preferably extends into each portion of the first transfer surface P 1', P1". However, the conductive line 9, connecting conductive elements of the interconnection track 4, can extend outside the portions of the first transfer surface PT, P1 "thus creating an additional shading to be taken into account in the calculation of the first. active surface Sa1. Likewise, one or more collection fingers connected to the conductive line 9 extend outside the portions of the first transfer surface PT, P1 ". They also create additional shading to be taken into account in the calculation of the first active area Sa1.

Tile distribution

The photovoltaic chain 101 has, for example, a length of the order of one meter. The photovoltaic chain 101 can then comprise thirty-six tiles having a width of 26 mm or thirty tiles having a width of 31.2 mm. The 26 mm tiles are, for example, obtained by cutting into six portions of a 156 mm by 156 mm substrate and the 31.2 mm tiles are obtained by cutting into five portions of the 156 mm by 156 mm substrate. It is also conceivable to cut tiles whose width is, for example, 27 mm. The latter tile can be obtained by cutting the substrate into five portions of 156 mm by 156 mm, however generating a drop of 21 mm. The advantage of a tile having a width of 31.2 mm is to avoid the generation of scrap during cutting. The drawback is to increase the total length of the photovoltaic chain 101 without increasing the maximum current generated because it is limited by one of the intermediate tiles 3 ′, 3 ". In an exemplary embodiment, the photovoltaic chain 101 can comprise thirty-five tiles. 26 mm wide and a first end tile 1 27 mm wide.

Whether using a 27 mm wide tile or a 31.2 mm wide tile to form the photovoltaic chain 101, in both cases it is necessary to have substrates having different metallizations, a first batch made up of substrates dedicated to cutting 26 mm tiles and a second batch consisting of substrates dedicated to cutting 27 mm or 31.2 mm tiles.

In order to optimize the use of the substrates by providing only one type of substrate, each substrate can have two types of metallization making it possible to cut five tiles of 25.9 mm and one tile of 26.5 mm, Thus, the photovoltaic chain 101 can comprise thirty 25.9 mm wide tiles and six 26.5 mm wide tiles, at least one 26.5 mm wide tile of which is placed in place of the first tile. end 1. The remaining five 26.5 mm tiles act as intermediate tiles and are distributed within the photovoltaic chain 101. Each 26.5 mm intermediate tile has an active area greater than each of the active areas of the intermediate 25 tiles. 9 mm, so the 26.5 mm intermediate tiles do not limit the maximum current of the photovoltaic chain 101.

More generally, the photovoltaic chain 101 can include, in addition to the first end tile, one or more intermediate tiles of greater width (and therefore of greater active surface) than the other intermediate useful , in order to optimize the use of photovoltaic cell substrates (in other words full size photovoltaic cells).

Bifacial tiles

The end and intermediate tiles 1, 2, 3 ', 3 "can be bifacial, that is to say that their front and rear faces are capable of picking up the electromagnetic radiation 50 to transform it into electric current. short-circuit current at the rear of a photovoltaic cell is defined as the maximum current generated by said photovoltaic cell when its rear face is oriented towards a source of illumination and its front face is hidden. Thus, the maximum current of the photovoltaic chain 101 comprising bifacial tiles 1, 2, 3 ', 3 ", is determined by the short-circuit current on the front face and rear face of each tile 1, 2, 3', 3 ".

In a second embodiment illustrated by Figure 2, the end and intermediate tiles 1, 2, 3 ', 3 "respectively comprise, on their rear faces, fifth, sixth, seventh and eighth active surfaces Sb1 , Sb2, Sb3 ', Sb3 ". The fifth, sixth, seventh and eighth active surfaces Sb1, Sb2, Sa3 ', Sb3 "occupy only a portion of each rear face, reduced by the second transfer surface P2 and the overlap surfaces V1, V2, V3: the fifth active surface Sb1 extends over the rear face of the first end tile 1, over the entire length W of the tile 1 and over a fifth exposed width B1. The fifth exposed width B1 is equal to the width L1 of the first end tile 1 minus the first overlap width Z1; the sixth active surface Sb2 extends over the rear face of the second end tile 2, over the entire length W of tile 2 and over a sixth width exposed B2 equal to L2 - R2. the seventh active surface Sb3 'extends over the rear face of the first intermediate tile 3', over the entire length W of tile 3 'and over a seventh exposed width B3' equal to L3 '- Z3. The eighth active surface Sa3 "extends over the rear face of the second intermediate tile 3 ", over the entire length W of tile 3" and over an eighth exposed width B3 "equal to L3" - Z2.

So that the maximum current of the photovoltaic chain 101 is not limited by the second end tile 2, the short-circuit current on the rear face of the second end tile 2 when the second transfer surface P2 is masked is advantageously greater than or equal to the short-circuit current on the rear face of an intermediate tile 3 ', 3 "when its covering surface is masked. The intermediate tile 3', 3" thus becomes the tile limiting the current of the photovoltaic chain 101. The limiting tile can be the first intermediate tile 3 ′, the second intermediate tile 3 ″ or another intermediate tile. An alternative embodiment of the photovoltaic chain 101 provides that the width L2 of the second end tile 2 is greater than the width L3 ', L3 "of the intermediate tile 3', 3". In this way, the sixth exposed length B2 is increased and the active surface Sb2 of the rear face of the second end tile 2 is greater than or equal to the active surface Sb3 ', Sb3 "of the rear face of the intermediate tile 3 ', 3 ". In this way, the second end tile 2 does not limit the maximum current of the photovoltaic chain 101 when the tiles 1, 2, 3 ', 3 "are bifacial.

Conductive interconnection track for bonding

Figures 3 to 6 schematically show several embodiments of the photovoltaic chain 101 and more particularly different ways of gluing the first metal connector 31 on the first interconnection tile 1. However, the teachings presented below can be transposed to the second interconnection tile 2 and to the second metal connector 32. In this case: by "first end tile 1", it should read "second end tile 2 by" front face ", it should read" rear face "by" first metal connector 31 ", it should read" second metal connector 32 ".

In the embodiment of Figure 3, also referring to Figure 4, the interconnection track 4 of the front face of the first end tile 1 comprises a plurality of conductive patterns with closed contour 6 spaced from each other, each closed-contour conductive pattern 6 comprising a closed contour 7 surrounding a portion of the front face 10.

The conductive patterns with closed contour 6 belonging to the conductive interconnection track 4 of the front face of the first end tile 1 are intended to accommodate portions of the second electrically conductive adhesive making it possible to bond the first connector 31 on the first end tile 1. The closed contours 7 make it possible to retain and locate the second electrically conductive adhesive when the first metal connector 31 is pressed, during the manufacture of the photovoltaic chain 101, against the front face of the first end tile 1. At least part of the closed-contour conductive patterns 6 each contain a portion of the second electrically conductive adhesive adhering to the front face portion 10 and to the first metal connector 31. For each portion of the second electrically conductive adhesive, a first part of the second electrically conductive adhesive is in contact with the metallized closed contour 7, while a second part of the second electrically conductive adhesive 7 is directly in contact with the substrate. Since the second electrically conductive adhesive has two to three times the adhesion to the substrate, the level of adhesion of the connection of the first metal connector 31 is thus improved. In addition, each portion of the second electrically conductive adhesive retained by the closed contour 7 is in contact with said closed contour 7 thus establishing electrical contact.

Preferably, each of the conductive patterns with closed contour 6 contains a portion of the second electrically conductive adhesive, making it possible to ensure better adhesion and better electrical connection.

The spacing between the conductive patterns with closed contour 6 has the effect of reducing the amount of conductive paste necessary for the realization of the conductive interconnection track 4.

The conductive interconnection track 4 preferably extends into the first transfer surface P1. Since each closed-contour conductor pattern 6 participates in the connection of the first metal connector 31, the closed-contour conductor patterns 6 are advantageously located in the first transfer surface P1 or are advantageously located in the portions of the first transfer surface P1 ′, P1 ".

Preferably, one or more conductive patterns with closed contour 6 are electrically connected to one or more collection fingers 5 each. For example, each conductive pattern with closed contour 6 can be electrically connected to a collection finger 5. The electrical connection is preferably made by a direct connection of each conductive pattern 6 with the collection finger 5. When the conductive patterns with closed contour 6 each include a conductive pad 8, the collecting finger 5 is preferably connected to each closed-contour conductive pattern 6, in the extension of the conductive pad 8. Closed contour

FIG. 5 schematically shows the conductive interconnection track 4 of the front face of the first end tile 1. FIG. 5 is in particular enlarged on two conductive patterns with closed contour 6. Each closed contour 7 may have a rectangular shape formed by four contiguous retention lines, connected to each other and arranged opposite in pairs. The retention lines are advantageously arranged perpendicular or parallel to the edge 11. Also, the term “retention line parallel to the edge 11” or “retention line perpendicular to the edge 11” will be called the lines being preferably arranged parallel or perpendicular to the edge 11. The rectangular shape of the closed contours 7 makes it possible to easily optimize the width of the conductive patterns with a closed contour 6 while keeping a surface of the portion of the first face 10 constant.

Each closed contour 7 has an outer width D, measured perpendicular to the edge 11 and an outer length G, measured parallel to the edge 11. The outer width and length D, G are preferably identical for all the closed contours 7 of the interconnection track 4. In order to limit the first transfer width R1, the outer width D is preferably between 400 μm and 1100 μm. Thus the first transfer width R1 can be between 0.8 mm and 1.5 mm. Since the closed contours 7 are disposed within the first transfer zone P1, the outer length G may be greater than the outer width, in order to optimize the front surface portion in contact with the second electrically conductive adhesive. For example, the outer length G can be between 700 µm and 2000 µm.

Each closed contour 7 also has an interior width C, measured perpendicular to the edge 11, and an interior length F, measured parallel to the edge 11. The interior width and length C, F are preferably identical for all the closed contours 7 of the interconnection track 4. The internal width C is preferably between 200 μm and 1000 μm. The internal length F is preferably between 500 μm and 1900 μm. The area of the front face portion 10 is equal to the product of the interior width C times the interior length F, and is preferably between 0.1 mm ² and 2.9 mm ² . The width Q of the retention lines parallel to the edge 11 is preferably less than twice the width N of a collecting finger 5. The retention lines parallel to the edge 11 do not need to be very wide. since it contributes little to mechanical adhesion. The primary role of the retention lines parallel to the edge 11 is to limit the creep of the second electrically conductive adhesive in a direction perpendicular to the edge 11. Thus, making retention lines parallel to the narrow edge 11 for the same external width D of closed contours 7 makes it possible to increase the internal width C and therefore the area of the front face portions 10 surrounded by the closed contours 7. When the width N of the collection fingers 5 is for example 50 μm, the retention lines parallel to the edge 11 advantageously have a width Q of less than 100 μm. For example, for a first transfer width R1 equal to 0.9 mm, the retention lines each have a width Q equal to 60 μm.

In the embodiment of Figure 6, at least part of the conductive patterns 6 each include a conductive pad 8, located inside the closed contour 7 and connected to the closed contour 7. Preferably, each of the patterns conductors 6 of the interconnection track 4 comprises a conductive pad 8. The conductive pad 8 makes it possible to reduce the resistive losses within the conductive interconnection track 4. During the interconnection, the portion of the second electrically conductive adhesive which is deposited on the conductive pattern 6 is in contact with a part of the closed contour 7. In the presence of the conductive pad 8, the surface of the conductive pad 8 is covered by the portion of the second adhesive thus establishing an additional electrical contact.

The conductive pad 8 is preferably oriented perpendicular to the edge 11, crossing the front face portion 10 on either side. The conductive pad 8 thus divides the portion of the front face 10 into two sub-portions of the front face. Preferably, the surfaces of the two front face sub-portions are equal.

The conductive pad 8 has a width K, measured parallel to the edge 11, greater than 1.5 times the width N of a collecting finger 5. When the width N of a collecting finger 5 is for example 50 μm, the conductive pad 8 has a width greater than 75 μm. However, in order to further reduce the resistive losses within the interconnection track 4, the conductive pad 8 may have a width K greater than or equal to twice the width N of a collecting finger 5. As a 'example, when the width n of a collecting finger 5 is equal to 50 μm, the conductive pad 8 has a width K equal to 120 μm, ie 2.4 times the width of a collecting finger.

When a collection finger 5 is connected to a conductive pattern 6 as illustrated in Figure 6, the conductive pad 8 is preferably located in the extension of the collection finger 5, in order to reduce the path traveled by the electric current from the collection finger 5 to the portion of the second electrically conductive adhesive.

When the conductive pad 8 has a width K less than twice the width N of a collecting finger 5, or when there is no conductive pad 8, the retention lines perpendicular to the edge 11 can advantageously have a width E, measured parallel to the edge 11, greater than 1.5 times the width N of a collecting finger 5. According to this configuration, said retention lines each have a surface making it possible to increase adhesion and d 'improve the electrical conductivity, compensating for the absence of the conductive pad 8 or a narrow conductive pad 8. During the interconnection of the first end tile 1, care will also be taken to cover said wide retention lines with a layer of the second electrically conductive adhesive in order to make an electrical contact. Again advantageously, the retention lines perpendicular to the edge 11 may have a width E equal to 2.4 times the width N of a collecting finger 5, making it possible to further improve the adhesion of said retention lines and the conductivity. electric. When the width N of the collection fingers 5 is for example 50 μm, the retention lines perpendicular to the edge 11 have a width greater than 100 μm, preferably equal to 120 μm.

When the conductive pad 8 has a width K equal to 2.4 times the width N of a collecting finger 5, the retention lines perpendicular to the edge 11 advantageously have a width E less than greater than 2 times the width N of a collecting finger 5. In this way said retention lines limit the creep of the second adhesive parallel to the edge 11 while increasing the area of the front face portion 10 surrounded by the closed contour 7. When the width N of the fingers collection is for example 50 μm, the retention lines perpendicular to the edge 11 may have a width E of between 50 μm and 100 μm. Conductive line

In the embodiment of Figure 6, the conductive interconnection track 4 comprises a conductive line 9 electrically connecting two conductive patterns with closed contour 6 consecutive. The conductive line 9 more particularly connects the closed contour 7 of a first pattern 6 with the closed contour 7 of a second pattern 6.

Preferably, the conductive line 9 is a broken line electrically connecting two by two all the conductive patterns 6 with closed contour. It comprises several portions, each portion of the first conductive line 9 connecting two consecutive conductive patterns 6. By virtue of the conductive line 9, the conductive interconnection track 4 is continuous, facilitating the measurement of electrical characteristics l (V) of the first end tile 1. In the case of a discontinuous interconnection track 4, it It is necessary to use a specific so-called "busbarless" material connecting each conductor pattern 6. [00127] In order to limit the number of conductive patterns with closed contour 6 and thus reduce the quantity of conductive paste necessary for their manufacture, the conductive line 9 is advantageously connected to one or more collecting fingers 5. In this way it is possible to connect collecting fingers 5 without increasing the number of conductive patterns 6. The electric current coming from a collecting finger 5 flows towards the conductive patterns 6 closest via the conductive line 9.

The conductive patterns with closed contour 6 of the conductive interconnection track 4 are preferably arranged within the first transfer surface portions R1 ′, P1 ″ in order to reduce the masking of the active face Sa1. conductive line 9 can extend outside the transfer surfaces R1 ′, P1 ″, allowing the connection of at least one collection finger 5 while limiting the masking on the first active surface Sa1.

Manufacturing process of the glued photovoltaic chain

[00129] FIG. 8 schematically represents an embodiment of a method for manufacturing a photovoltaic chain 210 according to a second aspect of the invention. The method 210 makes it possible to manufacture the photovoltaic chain 101 according to the first aspect of the invention. The method 210 comprises a supply step 211 of: the first end tile 1; the second end tile 2; the first and second intermediate tiles 3 ', 3 "; and the first metal connector 31.

[00131] The supply step 211 may in itself include the steps of manufacturing end tiles 1, 2 and intermediate tiles 3 ', 3 "from a semiconductor substrate. For example, the end tiles 1, 2 and the intermediate tiles 3 ', 3 "can come from a larger photovoltaic cell, called a full-size or full-plate photovoltaic cell, for example 156 mm by 156 mm, cut in the at least 4 portions, for example 5 portions of 31.5 mm by 156 mm or even 6 portions of 26 mm by 156 mm or else of different lengths.

The supply step 211 may include the screen printing of the conductive elements of each of the faces of the end tiles 1, 2 and of the intermediate tiles 3 ', 3 ", comprising in particular the conductive interconnection tracks 4 and the fingers collection 5. The conductive elements have a metallic character and are screen-printed from a conductive paste containing metallic particles, for example silver. electrical conduction and mechanical adhesion.

When the screen printing of the conductive interconnection track 4 uses a screen printing screen, the direction of the wires of which the component is parallel to the collection fingers 5, also known under the name of 0 ° screen screen printing or "knotless" printing "in English, it is not possible to screen print elements perpendicular to the collecting fingers 5. On the other hand, the form of broken line is achievable thanks to this technology. Thus, when the knotless screen printing is implemented for the screen printing of the conductive interconnection track 4, care will be taken to screen print a track having the shape of a broken line (or zig-zag), comprising short segments, of the around 100 μm long, inclined at an angle α with respect to the edge 11 of between 10 ° and 30 ° and preferably between 10 ° and 15 °. The method 210 comprises a first step of interconnection 212 of the first end tile 1 to the first intermediate tile 3 '. For this, at least a first portion of the first electrically conductive adhesive is deposited on the front face of the first intermediate tile 3 'and preferably on the conductive interconnection track 4 of the first intermediate tile 3'. The first portion of the first electrically conductive adhesive is advantageously deposited over the entire length of the conductive interconnection track 4. When it is a plurality of first portions of the first electrically conductive adhesive, the first portions of the first adhesive are distributed evenly over the entire length of the conductive interconnection track. In this way, the adhesion is uniformly distributed between the conductive interconnection track 4 and the first end tile 1. When the conductive interconnection track 4 of the first intermediate tile 3 'comprises a plurality of conductive patterns with contours closed 6, the first portions of the first electrically conductive adhesive are advantageously deposited on at least part of said conductive patterns with closed contours 6 and preferably on all the conductive patterns with closed contours 6. The first electrically conductive adhesive is preferably deposited by screen printing, printing. inkjet or dispensing in English.

The rear face of the first end tile 1 is pressed against the first portion or portions of the first electrically conductive adhesive in order to achieve the mechanical and electrical contact. Advantageously, when the rear face of the first end tile 1 comprises a conductive interconnection track 4, the latter is placed opposite the conductive interconnection track 4 of the front face of the first intermediate tile 3 'and pressed. against the first portion or portions of the first electrically conductive adhesive, thus ensuring good electrical contact. When the interconnecting conductive track 4 of the rear face of the first end tile 1 also comprises a plurality of closed-contour conductive patterns 6, the closed-contour conductive patterns 6 of the front face of the first intermediate tile 3 ' are advantageously aligned with the conductive patterns with closed contour 6 of the rear face of the first end tile 1, thus ensuring good mechanical contact. During the first interconnection step 212, the rear face of the first end tile 1 covers the first covering surface V1 of the front face of the first tile intermediate 3 ', the first covering surface V1 extending from the covered edge of the front face of the first intermediate tile 3' over a first covering width Z1.

The method 210 comprises a second interconnection step 213 of the second intermediate tile 3 "with the second end tile 2 performed in the same way as the first interconnection step 212. At least a second portion of the first electrically conductive adhesive is deposited on the front face of the second end tile 2 and preferably on the conductive interconnection track 4 and more preferably on at least part of the conductive patterns with closed contours 6 when the conductive track d interconnection 4 includes them.

The rear face of the second intermediate tile 3 "is pressed against the second portion or portions of the first electrically conductive adhesive. The rear face of the second intermediate tile 3" covers the second covering surface V2 of the front face of the second end tile 2, the second covering surface V2 extending from the covered edge of the front face of the second intermediate tile 3 "over a second covering width Z2.

The method 210 comprises a third step of connection 214 of the first metal connector 31 on the first end tile 1. For this, at least a third portion of the second electrically conductive adhesive is disposed on the first metal connector 31. The nature of the second electrically conductive adhesive, if it is different from the first electrically conductive adhesive used during the preceding steps, is preferably compatible with the nature of the first metallic connector 31. For example, the first connector 31 may be covered with a tin-lead alloy which may oxidize on contact with certain electrically conductive adhesives. The third portion of the second electrically conductive adhesive is advantageously deposited over the entire width W of the first metal connector 31, even when the conductive interconnection track 4 of the front face of the first end tile 1 comprises a plurality of conductive patterns at closed contour 6. In this way, the adhesion is uniformly distributed over the conductive interconnection track 4 of the front face of the first end tile 1. The first metal connector 31 is pressed against the front face of the first end tile 1 so that the third portion of the second electrically conductive adhesive is pressed against the front face of the first end tile 1. In this way the mechanical and electrical contact is made between the first end tile 1 and the first metal connector 31. The first metal connector 31 covers the first transfer surface P1 of the front face of the first end tile 1. The first transfer surface P1 extends from the covered edge of the front face of the first end tile 1, over the first transfer width R1. In order to guarantee the reliability of the photovoltaic chain 101 thus produced, it will be ensured that the first transfer width R1 is greater than each of the first and second covering widths Z1, Z2.

Preferably, care will also be taken to ensure that the first transfer surface P1 is greater than each of the first and second covering surfaces V1, V2.

The photovoltaic chain 101 undergoes a heat treatment of a few seconds to a few minutes at a temperature between 120 ° C and 160 ° C in order to crosslink the portions of the first and second electrically conductive adhesives.

Welded photovoltaic chain

FIG. 9 schematically represents a photovoltaic chain 102 according to a third aspect of the invention. This largely comprises the characteristics of the photovoltaic chain 101 according to the first aspect of the invention (illustrated by FIG. 1).

The difference with the photovoltaic chain 101 according to the first aspect of the invention lies in the connection technology of the first and second metal connectors 31, 32 on, respectively, the first and second end tiles 1, 2. According to the first aspect of the invention, the connections of the first and second metal connectors 31, 32 are made by means of the second electrically conductive adhesive, making it possible to maintain the same connection technology throughout the photovoltaic chain 101. According to the second aspect of the invention, the connections of the first and second metal connectors 31, 32 are made by directly soldering the first and second respectively connectors 31, 32 on each of the first and second end tiles 1, 2. The first metal connector 31 is welded to the first end tile 1 and preferably welded to the conductive interconnection track 4 of the front face of the first end tile 1. The first metal connector 31 covers the first transfer surface P1 of the front face of the first end tile 1, extending over the first transfer width R1 from the covered edge of the first end tile 1. The second metal connector 32 is welded to the second end tile 2 and preferably welded to the conductive interconnection track 4 or the metallization of the rear face of the second end tile 2. The second metal connector 32 covers the second surface transfer P2 from the rear face of the second end tile 2, extending over the second transfer width R2 from the covered edge of the second end tile 2. The welding of metallized surfaces, such as for example the first and second metal connectors 31, 32, has the advantage of providing better adhesion than the bonding of metallized surfaces by means of the second electrically conductive adhesive.

Welding thus makes it possible to limit the first and second transfer widths R1, R2 relative to the connections by means of the second adhesive while making the connections within the photovoltaic chain 102 more reliable. A first transfer width will preferably be chosen. R1 less than or equal to the largest of the first, second and third covering widths Z1, Z2, Z3 and more preferably substantially equal to the smallest of the covering widths Z1, Z2, Z3. Thus, the first active surface Sa1 of the first end tile 1 is not reduced compared to the second, third and fourth active surfaces Sa2, Sa3 ', Sa3 "and the first end tile 1 does not limit the current. maximum of the photovoltaic chain 102.

When the tiles 1, 2, 3 ', 3 "are bifacial, that is to say when the rear faces are capable of capturing the electromagnetic radiation to transform it into current, a second transfer width R2 will preferably be chosen less than or equal to the largest of the first, second and third overlap widths Z1, Z2, Z3 and more preferably substantially equal to the smallest of the overlap widths, Z1, Z2, Z3. Thus, the fifth active surface Sb1 of the first end tile 1 is not reduced compared to the sixth, seventh and eighth active surfaces Sb2, Sb3 ', Sb3 "and the second end tile 2 does not limit the maximum current of the photovoltaic chain 102.

Even more preferably, the first and second transfer surfaces P1, P2 are each less than or equal to the largest of the first, second and third covering surfaces V1, V2, V3.

The disjoint portions 31 ', 31 "of the first metal connector 31 make it possible to increase the first active surface Sa1 of the first end tile 1 by reducing the surface covered by the portions of the first transfer surface P1' and P1 ". So that the first end tile 1 does not limit the current of the photovoltaic chain 102, the transfer length and width of each of the disjoint portions 31 ', 31 "can be chosen such that the first active surface Sa1 is greater than or equal to to the active surface Sa3 ', Sa3 "on the front face of one of the intermediate tiles 3', 3". For the same first active surface Sa1, reducing the length of each separate portion 31 ', 31 "makes it possible to increase the transfer widths R1 ′, R1 ″ of each separate portion 31 ′, 31 ″ such that it is greater than each of the first and second cover widths Z1, Z2. In this way, the reliability of the connection is enhanced.

Conductive interconnection track for welding

The welding of the first and second connectors 31 requires the implementation of a filler alloy. The filler alloy, when it is molten, only wets the metallized areas, such as the conductive interconnection tracks 4 or the collection fingers 5. The conductive interconnection track 4 preferably extends into the first transfer surface P1 in order to be contacted by the filler alloy.

The conductive interconnection track 4 may be continuous and preferably does not have a conductive pattern with a closed contour, thus offering a large metallized surface to facilitate wetting of the filler alloy. The conductive interconnection track 4 can extend along the covered edge, over the entire length Wdu edge. However, in order to limit the differential thermal expansion, it is preferable that the first metal connector 31 comprises the plurality of separate portions 3T, 31 ", each portion 3T, 31" being soldered to the conductive interconnection track 4. In the embodiment of Figure 10, the conductive interconnection track 4 may comprise a plurality of discontinuous portions extending in the first transfer surface P1, parallel to the covered edge of the first end tile 1 Thus, even when the conductive interconnection track 4 is soldered to the first metal connector 31, the differential thermal expansion is reduced. For example, the conductive interconnection track 4 may have six discontinuous portions 24.5 mm wide or else fifteen discontinuous portions 10 mm wide. The differential expansion can be further reduced when the first metallic connector 31 comprises the plurality of disjoint portions 31 ', 31 ". Preferably, the disjoint portions of the first metallic connector 31', 31" each connect at least one of the discontinuous portions. of the interconnection track 4, as illustrated in FIG. 11. For example, the first metal connector 31 may comprise six disjoint portions 31 ', 31 "of 11 mm long, spaced 17.5 mm apart, or even twelve portions disjoint 31 ', 31 "5 mm long spaced 8.5 mm apart.

In the embodiment of Figure 11, the conductive interconnection track 4 comprises the conductive line 9 electrically connecting two consecutive discontinuous portions of the conductive interconnection track 4. The conductive line 9 also allows to electrically connect a collection finger located outside the portions of the first transfer surface P1 ′, P1 ". Preferably, the conductive interconnection track 4 comprises several portions electrically connecting all the discontinuous portions of the conductive interconnection track 4. Thus, the track interconnection conductor is continuous, facilitating the measurement of electrical characteristics l (V) of the first end tile 1. In the case of a discontinuous interconnection track 4, it is necessary to use a specific material called " busbarless ".

Double printing

Two types of conductive paste make it possible to screen print the conductive elements on the front face of the first end tile 1. The so-called high temperature conductive pastes are mainly used on homojunction type substrates. The high temperature conductive pastes are heated to a temperature above 700 ° C, allowing the fusion of a vitreous phase allowing adhesion. So-called low temperature conductive pastes are mainly used on heterojunction type substrates. The low-temperature conductive pastes have a crosslinking temperature of the order of 250 ° C. They do not contain a vitreous phase and adhesion is obtained by the resin contained in the paste.

In order to obtain a solder of the first metal connector 31 having good resistance to tearing for a homojunction substrate, the high temperature conductive paste making it possible to produce the conductive interconnection track 4 will advantageously have a high silver content , greater than 70% and preferably greater than 80%.

In order to obtain a solder of the first metal connector 31 having good resistance to tearing for a heterojunction substrate, the conductive interconnection track 4, made from a low temperature conductive paste, will have a height greater than 15 μm and preferably greater than or equal to 25 μm.

Bonding / welding

A certain type of electrically conductive adhesive is charged with so-called fusible metal particles, ie capable of melting. It is for example a resin or a polymer comprising tin-lead alloy particles. This type of electrically conductive adhesive exhibits good adhesion to the substrate and can be heated in order to weld metal surfaces. In order to achieve a weld having good resistance to tearing, it is necessary to have sufficiently large metallized surfaces. The conductive interconnection track 4 can for example comprise twelve disjoint portions of dimension 0.3 mm by 11.5 mm on which the welding is carried out, the twelve portions being spaced 1.5 mm apart within which the electrically conductive adhesive will join.

Manufacturing process of the welded photovoltaic chain

[00156] FIG. 12 schematically represents a method 220 for manufacturing a photovoltaic chain according to a fourth aspect of the invention. The method 220 makes it possible to manufacture the photovoltaic chain 102 according to the third aspect of the invention. This method 220 comprises the same steps as the manufacturing method 210 according to the second aspect of the invention except the step of connecting 214 the first metal connector 31 to the first end tile 1. According to the second aspect of the invention, the connection is made by means of a third portion of the second electrically conductive adhesive. The connection of the first connector 31 to the first end tile 1 according to the fourth aspect of the invention is carried out by a welding step 224.

During the welding step 224, the first connector element 31 is covered with a fusible alloy which will play a role of filler metal. The fusible alloy is typically a tin-lead alloy or a tin-lead-silver alloy. The first metal connector 31 is brought into contact with the front face of the first end tile 1, covering the first transfer surface P1, and the assembly is then brought to a temperature of the order of 200 ° C, making melt the fusible alloy. During cooling, the fusible alloy solidifies making the electrical and mechanical connection with the first end tile 1. Preferably, the first metal connector 31 is brought into contact with the conductive interconnection track 4 of the front face of the first tile. end 1. In fact, when the fusible alloy is melted, it only wets on metallized elements such as the conductive interconnection track 4. In order not to degrade the first electrically conductive adhesive placed within the other interconnections , localized heating will be preferred, for example carried out by means of a thermal probe, also called a thermode.

In order not to resort to localized heating equipment such as the thermode, a first alternative of the welding step 224 provides for the use of a so-called low temperature fusible alloy, comprising a tin-bismuth-silver alloy, of which the melting temperature is of the order of 150 ° C., corresponding to the crosslinking temperature of the first electrically conductive adhesive.

A second alternative of the welding step 224 provides for the use of a solder paste deposited on the conductive interconnection track 4. The solder paste is deposited on the first metal connector 31, advantageously over the entire width W of the first metal connector 31. In this way, the adhesion is uniformly distributed over the conductive interconnection track 4 of the first end tile 1. Secondly, the first metal connector 31 is pressed against the front face of the first end tile 1 and in particular against the conductive interconnection track 4. The solder paste is heated locally in order to melt the solder paste and perform the soldering.

During the step of providing 211 end and intermediate tiles according to the fourth aspect of the invention, the screen printing of the conductive elements on the front face of the first end tile 1, such as the conductive track interconnection 4 or the collection fingers, is advantageously made from a conductive paste formulated both to allow the production of collection fingers 5 and the conductive interconnection track 4, for example for a heterojunction substrate, one of Kyoto Elex ™ L359 ™ or Q119 ™ conductive pastes. However, two different conductive pastes will preferably be used to make the collection fingers 5 on the one hand, and the conductive interconnection track 4 on the other hand. The screen printing of the collection fingers 5 and of the conductive interconnection track 4 is carried out twice, also called dual print in English. The conductive paste making it possible to make the collection fingers 5, such as for example the M931 ™ conductive paste from Kyoto Elex ™, has a low resistivity and allows the printing of narrow conductors, less than 50 μm. The conductive paste making it possible to produce the conductive interconnection track 4, such as for example the conductive paste R101 ™ from Kyoto Elex ™, exhibits high adhesion and compatibility with the soldering process.

In order to avoid the dissolution of the silver contained in the collection fingers 5 during the welding step 224, the screen printing of the conductive paste making it possible to produce the conductive interconnection track 4 will slightly overlap each finger of collection 5. This precaution is particularly advantageous when the collection fingers 5 are made from a low-temperature conductive paste, particularly suitable for dissolving silver. The screen printing of the collection fingers 5 can be carried out in two stages in order to reduce their resistivity, also called double printing or double print in English. Double printing allows the use of two different conductive pastes, each optimized for a function. Thus during the first screen printing, the collection fingers 5 and the interconnection track 4 are for example screen printed from a conductive paste compatible with the welding process, such as the conductive paste R103 ™ from Kyoto Elex ™. The second screen printing makes it possible to increase the thickness of the conductive interconnection track 4, covering a part of each collecting fingers 5. For this, a low resistive conductive paste will be used, such as for example M931 ™ conductive paste from Kyoto Elex ™.

Claims

[Claim 1] Photovoltaic chain (101) comprising:

- a first photovoltaic cell (1) called the first end tile;

- a second photovoltaic cell (2) called the second end tile;

- a plurality of third photovoltaic cells (3 ', 3 ") called intermediate tiles, arranged between the first and second end tiles (1, 2); and

- a first metal connector (31); each of the first, second and third photovoltaic cells (1, 2, 3 ', 3 ") comprising a front face and a rear face opposite the front face, the first end tile (1), the intermediate tiles (3' , 3 ") and the second end tile (2) being interconnected by means of a first electrically conductive adhesive, the first end tile (1) being interconnected with a first intermediate tile (3 '), the rear face of the first end tile (1) covering a surface (V1) of the front face of the first intermediate tile (3 '), called the first covering surface, the first covering surface (V1) having a first covering width (Z1), the second end tile (2) being interconnected with a second intermediate tile (3 "), the rear face of the second intermediate tile (3") covering a surface (V2) of the front face of the second end tile (2), called the second covering surface, the second surface cover (V2) having a second cover width (Z2), the first metal connector (31) being connected to the first end tile (1) by means of a second electrically conductive adhesive, the first metal connector (31) ) covering a surface (P1) of the front face of the first end tile (1), called the first transfer surface, the first transfer surface (P1) having a first transfer width (R1) greater than each of the first and second overlap widths (Z1, Z2).

[Claim 2] Photovoltaic chain (101) according to the preceding claim, in which the short-circuit current on the front face of the first end tile (1) when the first transfer surface (P1) is masked is greater than or equal to the short-circuit current on the front face of an intermediate tile (3 ', 3 ") when its covering surface (V1, V3) is masked. [Claim s] Photovoltaic chain (101) according to the preceding claim, wherein the short circuit current on the front face of the first end tile (1) when its front face is fully exposed is greater than the short circuit current on the front face of the intermediate tile (3 ',

3 ") when its front face is fully exposed.

[Claim 4] Photovoltaic chain (101) according to one of claims 2 and 3, in which the active surface (Sa1) on the front face of the first end tile (1) is greater than or equal to the active surface (Sa3 ', Sa3 ") on the front face of the intermediate tile (3', 3").

[Claim s] Photovoltaic chain (101) according to any one of claims 2 to 4, wherein the width (L1) of the first end tile (1) is greater than the width (L3 ', L3 ") of the intermediate tile (3 ', 3 ").

[Claim 6] A photovoltaic string (101) according to any preceding claim, wherein the front face of the first end tile (1) comprises an interconnecting conductive track (4) extending into the first surface. transfer (P1), the interconnecting conductive track (4) comprising a plurality of closed-contour conductor patterns (6) spaced apart from each other, each closed-contour conductor pattern (6) comprising a closed contour (7) surrounding a portion of the front face (10), at least a part of the closed-contour conductive patterns (6) each containing a portion of the second electrically conductive adhesive adhering to the portion of the front face (10) and to the first metal connector (31 ).

[Claim 7] Photovoltaic chain (101) according to the preceding claim, in which the conductive interconnection track (4) comprises a conductive line (9) electrically connecting two conductive patterns with closed contour (6) consecutive.

[Claim s] Photovoltaic string (101) according to any one of the preceding claims, wherein the first metal connector (31) comprises a plurality of disjoint portions (31 ', 31 "), connected to the first end tile ( 1), each portion (31 ', 31 ") of the first metal connector (31) covering a surface (R1', P1") of the front face of the first end tile (1), said portion of the first surface of carry over, each portion of first transfer surface (P1 ', P1 ") having a transfer width (R1 R1") greater than each of the first and second cover widths (Z1, Z2).

[Claim 9] A photovoltaic chain (101) according to any one of the preceding claims, further comprising:

- a second metal connector (32); the second metal connector (32) being connected to the second end tile (2) by means of the second electrically conductive adhesive, the second metal connector (32) covering a surface (P2) of the rear face of the second tile of end (2), called the second transfer surface, the second transfer surface (P2) having a second transfer width (R2) greater than each of the first and second covering widths (Z1, Z2).

[Claim 10] Photovoltaic chain (101) according to the preceding claim, in which the short-circuit current on the rear face of the second end tile (2) when the second transfer surface (P2) is masked is greater than or equal to the short-circuit current on the rear face of an intermediate tile (3 ', 3 ") when its covering surface (V2, V3) is masked.

[Claim 11] A method (201) for manufacturing a photovoltaic chain comprising the following steps:

- providing (211) a first photovoltaic cell (1) called first end tile, a second photovoltaic cell (2) called second end tile, a plurality of third photovoltaic cells (3 ', 3 ") called intermediate tiles and a first metal connector (31), each of the first, second and third photovoltaic cells (1, 2, 3 ', 3 ") comprising a front face and a rear face opposite to the front face;

- interconnect (212) the first end tile (1) to a first intermediate tile (3 ') by means of a first electrically conductive adhesive, the rear face of the first end tile (1) covering a surface ( V1) of the front face of the first intermediate tile (3 '), called the first covering surface, the first covering surface (V1) having a first covering width (Z1);

- interconnect (213) a second intermediate tile (3 ") to the second end tile (2) by means of the first electrically adhesive conductive, the rear face of the second intermediate tile (3 ") covering a surface (V2) of the front face of the second end tile (2), called the second covering surface, the second covering surface (V2) having a second overlap width (Z2);

- connect (214) the first metal connector (31) to the first end tile (1) by means of a second electrically conductive adhesive, the first metal connector (31) covering a surface (P1) of the front face of the first end tile (1), called the first transfer surface, the first transfer surface (P1) having a first transfer width (R1) greater than each of the first and second cover widths (Z1. Z2).

[Claim 12] Photovoltaic chain (102) comprising:

- a first photovoltaic cell (1) called the first end tile;

- a second photovoltaic cell (2) called the second end tile;

- a plurality of third photovoltaic cells (3) called intermediate tiles, arranged between the first and second end tiles (1, 2); and

- a first metal connector (31); each of the first, second and third photovoltaic cells (1, 2, 3 ', 3 ") comprising a front face and a rear face opposite the front face, the first end tile (1), the intermediate tiles (3' , 3 ") and the second end tile (2) being interconnected by means of a first electrically conductive adhesive, the first end tile (1) being interconnected with a first intermediate tile (3 '), the rear face of the first end tile (1) covering a surface (V1) of the front face of the first intermediate tile (3 '), called the first covering surface, the first covering surface (V1) having a first covering width (Z1), the second end tile (2) being interconnected with a second intermediate tile (3 "), the rear face of the second intermediate tile (3") covering a surface (V2) of the front face of the second end tile (2), called the second covering surface, the second surface cover (V2) having a second cover width (Z2), the first metal connector (31) being connected to the first end tile (1), the first metal connector (31) covering a surface (P1) of the front face of the first end tile (1), called the first transfer surface, the first metal connector (31) being welded to the first end tile (1), the active surface ( Sa1) on the front face of the first end tile (1) being greater than or equal to the active surface (Sa3 ', Sa3 ") on the front face of an intermediate tile (3', 3").

[Claim 13] A photovoltaic chain (102) according to claim 12, wherein the front face of the first end tile comprises an interconnecting conductive track (4) extending over the first transfer surface (P1), the first metal connector (31) being soldered to the conductive interconnection track (4).

[Claim 14] A photovoltaic chain (102) according to claim 13, wherein the interconnecting conductive track (4) is continuous.

[Claim 15] A photovoltaic chain (102) according to claim 14, wherein the conductive interconnection track (4) comprises a plurality of disjoint portions, each portion being soldered to the first metal connector (31).

[Claim 16] Photovoltaic chain (102) according to the preceding claim, in which the conductive interconnection track (4) comprises a conductive line (9) electrically connecting two consecutive portions of the conductive interconnection track (4).

[Claim 17] A photovoltaic string (102) according to any one of claims 12 to 16, wherein the first metal connector (31) comprises a plurality of disjoint portions (31 ', 31 ") welded to the first end tile (1), each portion (31 ', 31 ") of the first metal connector (31) covering a surface (P1', P1") of the front face of the first end tile (1), called the first surface portion of postponement.

[Claim 18] Photovoltaic chain (102) according to claim 17, in which each portion of the first transfer surface (R1 ', P1 ") has a transfer width (R1', R1") greater than each of the first and second widths. overlap (Z1, Z2).

[Claim 19] Photovoltaic chain (102) according to any one of claims 12 to 17, in which the first transfer surface (P1) has a first transfer width (R1) substantially equal to the first and second cover widths (Z1, 72).

[Claim 20] A photovoltaic chain (102) according to any one of claims 12 to 19, further comprising:

- a second metal connector (32); the second metal connector (32) being welded to the second end tile (2), the second metal connector (32) covering a surface (P2) of the rear face of the second end tile (2), called second transfer surface, the second metal connector (32) being welded to the second end tile (2).

[Claim 21] A method (220) for manufacturing a photovoltaic chain comprising the following steps:

- providing (221) a first photovoltaic cell (1) called first end tile, a second photovoltaic cell (2) called second end tile, a plurality of third photovoltaic cells (3 ', 3 ") called intermediate tiles, and a first metallic connector (31), each of the first, second and third photovoltaic cells (1, 2, 3 ', 3 ") comprising a front face and a rear face opposite to the front face;

- interconnect (222) the first end tile (1) to a first intermediate tile (3 ') by means of a first electrically conductive adhesive, the rear face of the first end tile (1) covering a first surface (V1) of the front face of the first intermediate tile (3 '), called the first covering surface, the first covering surface (V1) having a first covering width (Z1);

- interconnect (223) a second intermediate tile (3 ") to the second end tile (2) by means of the first electrically conductive adhesive, the rear face of the second intermediate tile (3") covering a surface (V2) of the front face of the second end tile (2), called the second covering surface, the second covering surface (V2) having a second covering width (Z2);

- soldering (224) the first metal connector (31) to the first end tile (1), the first metal connector (1) covering a surface (P1) of the front face of the first end tile (1), called the first transfer surface.