EP4348718A1

EP4348718A1 - Photovoltaic strings and cells

Info

Publication number: EP4348718A1
Application number: EP22730908.5A
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: 2021-06-04
Filing date: 2022-05-31
Publication date: 2024-04-10
Also published as: US20240290892A1; FR3123761A1; FR3123761B1; WO2022253813A1

Abstract

One aspect of the invention relates to a photovoltaic cell (CELL) comprising a distribution track (DIS1) extending parallel to one edge (BA) and a plurality of collection fingers (COL), the photovoltaic cell being noteworthy in that the width (WDIS1) of the distribution track (DIS1) is larger than the width (WCOL) of each collection finger (COL); and in that a plurality of interconnect conductors (INT) are electrically connected to the distribution track (DIS1) and extend between said edge (BA) and the distribution track (DIS1); and in that it comprises at least one free segment (LC) of its face (AV), bounded at least partially by the distribution track (DIS1), the edge (BA) and two consecutive interconnect conductors (INT).

Description

DESCRIPTION

TITLE: PHOTOVOLTAIC CELLS AND STRINGS

TECHNICAL FIELD OF THE INVENTION

The technical field of the invention is that of photovoltaic cells electrically connected and partially overlapping. The present invention relates more particularly to the architecture of metallizations on at least one face of a photovoltaic cell. The invention also relates to the connection of a plurality of photovoltaic cells according to the invention.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] The photovoltaic modules are produced by placing a plurality of photovoltaic cells in series, forming a photovoltaic chain, followed by the encapsulation of the latter so as to form a photovoltaic module. The process commonly used for the formation of photovoltaic chains is the welding or gluing of ribbons or wires on the collection fingers of the front face of a first cell and on the collection fingers of the rear face of a second cell. . The first and second cells are separated by a few millimeters, about 3 mm, so that the ribbon or wire can change plane and pass from the front face of the first cell to the back face of the second cell. The spacing between the two cells increases the surface of the chain thus formed and therefore that of the final module.

There is a technique for interconnecting photovoltaic cells called "shingle" (translation of "shingle" or "tile" in English) which does not use ribbons or electric wires, making it possible to provide a response to the increase in the active surface of the module. 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 chain are superimposed on top of each other, a lower cell being partially covered by the adjacent upper cell, in the same way that tiles cover a roof. The interconnection between two adjacent cells is made in the overlap zone. The front face of the lower cell and the rear face of the upper cell each have an array of collection fingers connected to a wide metallic track extending along one edge. During the interconnection of the chain, the two metallized tracks are electrically and mechanically connected by welding or by means of an electrically conductive adhesive placed between the two metallized tracks. The photovoltaic chains thus make it possible to eliminate the separation between the cells, offering a continuous active surface over the entire surface of the photovoltaic chain.

[0004] However, photovoltaic chains interconnected in shingles pose new problems. Firstly, the electrical and mechanical reliability of the photovoltaic module imposes a large overlapping area between the adjacent cells within the photovoltaic chain. A part of each cell, having undergone the entire functionalization process, is not illuminated by solar radiation and is therefore not used. Today, the manufacturing processes for photovoltaic chains require an overlapping area of the order of 1.5 mm for photovoltaic cells of 156 mm×156 mm, which corresponds to an unused photovoltaic cell surface of about 1%. There is therefore a need to reduce the overlap zone between the adjacent cells to reduce the unused surface of each photovoltaic cell while maintaining good electrical and mechanical reliability.

[0005] A first document, published under the reference FR 3 094570, discloses a photovoltaic chain comprising first and second photovoltaic cells, the front face of the first photovoltaic cell being intended to be exposed to incident radiation and the rear face of the second photovoltaic cell being interconnected to the front face of the first photovoltaic cell. The first document discloses in particular that the front face of the first photovoltaic cell has a plurality of collection fingers and an interconnection conductive track extending parallel to an edge of the photovoltaic cell less than 2 mm from said edge. The interconnection between the two photovoltaic cells is then ensured by an electrically conductive adhesive in contact with the conductive interconnection track of the first photovoltaic cell and the rear face of the second photovoltaic cell. The conductive interconnection track can be made from so-called “high temperature” metallizations. High temperature metallizations include a glass matrix and metallic particles. The glass matrix imparts, when heat-treated at a temperature of around 800°C, high adhesion to these metallizations on the surface of the cell. The interconnection is then carried out by depositing a portion of crosslinking adhesive at low temperature on the interconnection track of the front face of the first photovoltaic cell. A crosslinking heat treatment of the electrically conductive adhesive at a temperature of the order of 200° C. thus makes it possible to produce the thermal and mechanical connection between the two photovoltaic cells.

[0006] This type of interconnection shows good mechanical reliability. On the other hand, the treatment temperature of the high temperature metallizations is not compatible with certain types of photovoltaic cells such as heterojunction photovoltaic cells. Indeed, the latter can be damaged when the temperature exceeds 250°C for a few minutes. The interconnection conductive track can therefore be made using a so-called "low temperature" metallization ink. Said ink notably comprises a resin and metallic particles. The adhesion of these low temperature metallizations, which do not contain glass, is not as high as that of high temperature metallizations, reducing the reliability of the interconnection between the cells. On the other hand, a heat treatment at a temperature of the order of 200° C. is sufficient to achieve the thermal and mechanical connection of the first interconnection track on the face of the first photovoltaic cell. Reliability is however also reduced by the electrically conductive adhesive, comprising for example epoxy or acrylate, exhibiting poor adhesion to low temperature metallizations.

[0007] A second document, published under the reference WO 2020/109408, discloses a photovoltaic cell making it possible to improve the interconnection between said cell and a metallic interconnecting tape when it is produced with a low-temperature adhesive. The disclosed cell includes metallizations forming a plurality of closed conductive contours surrounding a portion of the substrate. In order to make the interconnection, the low temperature adhesive is deposited on each closed conductive contour so as to adhere both to the metallizations and to the substrate. The low temperature adhesive indeed shows a higher adhesion with the substrate than with the metallizations. Thus, the closed contours offer a metallized area making it possible to provide a good electrical connection and offer a portion of the substrate making it possible to improve the adhesion compared to a deposition only on a metallized area. On the other hand, the surface of the substrate in contact with the adhesive by relative to the quantity of adhesive used remains low and does not make it possible to significantly improve the mechanical robustness of the interconnection while maintaining a good quality of electrical contact.

[0008] There is therefore a need to further improve the interconnection between photovoltaic cells interconnected in shingles, in particular when the interconnection uses a low-temperature adhesive.

SUMMARY OF THE INVENTION

The invention offers a solution to the problems mentioned above, by making it possible to significantly increase the quantity of adhesive participating in the mechanical connection between two photovoltaic cells. The invention also makes it possible to increase the level of adhesion of the adhesive to at least one of the photovoltaic cells. In this way, the robustness of the interconnection is improved.

For this, the invention relates to a photovoltaic cell comprising a first face, said first face comprising: a first edge; a first dispensing track extending parallel to the first edge and less than 5 mm from the first edge, preferably less than 4 mm and even more preferably less than 3 mm; a plurality of collection fingers extending parallel to each other, said collection fingers being electrically connected to the first distribution track.

[0011] The photovoltaic cell is remarkable in that: the width of the first distribution track is strictly greater than the width of each collection finger; and in that the first face also comprises: a plurality of first interconnect conductors, said first interconnect conductors being electrically connected to the first distribution track and extending perpendicular to the first edge between said first edge and the first track distribution, the first interconnection conductors being spaced apart in pairs; and at least a first central free portion of the first face delimited at least in part by the first distribution track, the first edge and two first consecutive interconnection conductors.

[0012] The term "collection finger" means a conductive track intended to collect the electric currents produced by the photovoltaic cell.

[0013] The term "distribution track" means a conductive track configured to achieve the concentration of the electric currents collected by the collection fingers and the distribution of these electric currents to the first interconnection conductors.

[0014] The arrangement of the first distribution track and of the collection fingers makes it possible, on the one hand, to collect and concentrate the electric currents produced in the vicinity of the first edge. The distribution track also makes it possible to distribute the electric currents collected between the first interconnecting conductors. In this way, the photovoltaic cell makes it possible to ensure good electrical interconnection when it is interconnected within a photovoltaic chain.

On the other hand, the arrangement of the first distribution track and the first interconnection conductors on the first face also makes it possible to delimit a portion of the first face devoid of metallization, in order to be able to deposit a portion of 'adhesive. This portion of adhesive then does not adhere to any metallization and therefore offers, for a given quantity of adhesive, optimum adhesion.

[0016] In addition to the characteristics which have just been mentioned in the preceding paragraphs, the photovoltaic cell according to the invention may have one or more additional characteristics from among the following, considered individually or according to all technically possible combinations: the collection fingers s extend parallel to the first edge and the collection fingers are electrically connected to the first distribution track by means of connection elements in the form of wires or ribbons extending perpendicular to the first edge, each connection element being preferably arranged in extending each first interconnect conductor; the width of each first central free portion is greater than the pitch separating the collection fingers; the width of the first dispensing track is greater than or equal to twice the width of each collection finger; the width of each first interconnect conductor is greater than or equal to the width of the first distribution track; the first interconnect conductors each include an interconnect pattern; the first face comprises a second distribution track extending parallel to the first edge between the first distribution track and the collection fingers, the second distribution track being electrically connected to the first distribution track and preferably by means of a plurality connecting conductors each extending perpendicularly to the first edge, the width of the second distribution track being greater than the width of each collection finger and preferably equal to the width of the first distribution track; the photovoltaic cell comprises a second face opposite the first face, said second face comprising a second edge, opposite the first edge; a third dispensing track extending parallel to the second edge; a plurality of second first interconnection conductors being electrically connected to the third distribution track and extending perpendicular to the second edge between said second edge and the third distribution track, the second interconnection conductors being spaced apart in pairs; and at least a second central free portion delimited in part by the third distribution track, the second edge and two second consecutive interconnection conductors; the width of each second central free portion is equal to the width of each first central free portion; each second central free portion is opposite a first central free portion; and the photovoltaic cell comprises a semiconductor stack, said semiconductor stack preferably being heterojunction.

The invention also relates to a method of manufacturing a photovoltaic cell according to the invention, comprising the following steps: forming on a first face of a substrate, a first distribution track extending parallel to a first edge and less than 5 mm from the first edge and a plurality of collection fingers extending parallel to each other, said collection fingers being electrically connected to the first distribution track, the width of the first distribution track being strictly greater than the width of each collection finger; and forming on the first side of the substrate a plurality of first interconnect conductors, said first interconnect conductors being electrically connected to the first distribution track and extending perpendicular to the first edge between said first edge and the first distribution track. distribution, the first interconnection conductors being spaced apart in pairs and at least a first central free portion of the first face being delimited at least in part by the first distribution track, the first edge and two consecutive first interconnection conductors.

Another aspect of the invention relates to a photovoltaic chain comprising: a first photovoltaic cell according to the invention; a second photovoltaic cell; and at least a first portion of adhesive.

Said second photovoltaic cell is linked to the first photovoltaic cell by means of each first portion of adhesive, one face of the second photovoltaic cell partially covering the first face of the first photovoltaic cell, each first portion of adhesive adhering to a first central free portion of the first face of the first photovoltaic cell and to the face of the second photovoltaic cell. [0020] In addition to the characteristics which have just been mentioned in the preceding paragraphs, the photovoltaic chain according to the invention may have one or more additional characteristics from among the following, considered individually or according to all the technically possible combinations: each first portion of adhesive is remote from each first interconnection conductor of the first face of the first photovoltaic cell; each first portion of adhesive is separated by at least 1 mm from each first interconnection conductor of the first face of the first photovoltaic cell; a plurality of first portions of adhesive adhere to the first central free portion of the first face of the first photovoltaic cell and to the face of the second photovoltaic cell; the sum of the lengths of each first portion of adhesive is less than the width of the first central free portion; the face of the second photovoltaic cell comprises an edge plumb with the first face of the first photovoltaic cell, each first portion of adhesive being spaced from the first edge of the first face of the first photovoltaic cell and from the edge of the face the second photovoltaic cell; each first portion of adhesive is at least 0.05 mm from the first edge of the first face of the first photovoltaic cell and from the edge of the face of the second photovoltaic cell; the face of the second photovoltaic cell covers the first edge and partially the first face of the first photovoltaic cell over an overlapping distance from the first edge, the width of each first portion of adhesive being less than the length of the overlap; the photovoltaic string comprises a plurality of second portions of electrically conductive adhesive, each second portion of adhesive electrically connecting a first interconnecting conductor of the first face of the first photovoltaic cell to the face of the second photovoltaic cell the length of each first portion of adhesive is greater than the length of each second portion of adhesive; the width of each first portion of adhesive is greater than the width of each second portion of adhesive; and the face of the second photovoltaic cell includes a plurality of discrete electrodes spaced from each first interconnect conductor of the first face of the first photovoltaic cell, each second portion of adhesive connecting a first interconnect conductor to a discrete electrode .

Finally, a last aspect of the invention relates to a method for manufacturing a photovoltaic chain comprising the following steps: providing a first photovoltaic cell according to the invention, a second photovoltaic cell and at least a first portion of adhesive ; depositing each first portion of adhesive on a first central free portion of the first face of the first photovoltaic cell; and bonding the second photovoltaic cell to the first photovoltaic cell by means of each first portion of adhesive, one side of the second photovoltaic cell partially covering the first side of the first photovoltaic cell, each first portion of adhesive adhering to a first portion central free of the first face of the first photovoltaic cell and to the face of the second photovoltaic cell.

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

BRIEF DESCRIPTION OF FIGURES

The figures are presented for information only and in no way limit the invention. [0024] [Fig. 1], [Fig. 2], [Fig. 3], [Fig. 4], [Fig. 5], [Fig. 6] schematically represent first, second, third, fourth, fifth, sixth embodiments of a photovoltaic cell according to the invention.

[0025] [Fig. 7] schematically represents an embodiment of a method of manufacturing a photovoltaic cell according to the invention.

[0026] [Fig. 8], [Fig. 9], [Fig. 10], [Fig. 11], [Fig. 12], [Fig. 13] schematically represent first, second, third, fourth, fifth, sixth embodiments of a photovoltaic chain according to the invention.

[0027] [Fig. 14] schematically represents an embodiment of a method for manufacturing a photovoltaic chain according to the invention

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

DETAILED DESCRIPTION [0029] The [Figs. 1] to [Fig. 6] illustrate different embodiments of a photovoltaic cell CELL according to the invention. The CELL photovoltaic cell, which can also simply be called a CELL cell, offers a means of improving the interconnection with another photovoltaic cell in a "shingle" type photovoltaic chain, also called a "shingle" in English. By "shingle" is meant a stack of cells partially overlapping in the same way that the tiles of a roof overlap, a zone of the rear face of an upper cell being electrically and mechanically connected to a zone of the face front of a lower cell. The cell CELL according to the invention makes it possible in particular to improve the robustness of the mechanical connection with at least one other cell of a photovoltaic chain.

The CELL cell according to the invention offers a particular advantage when it comprises metallizations produced from a so-called "low temperature" paste and when the mechanical interconnection between the cells is carried out by means of an adhesive called "low temperature". The low temperature paste and the low temperature adhesive comprise for example an epoxy or acrylate based resin. For this, the CELL cell is advantageously made from a homojunction or heterojunction semiconductor stack. In the latter case, the semiconductor stack can advantageously comprise a conductive transparent oxide layer making it possible to carry out part of the collection of the electric currents generated by the finished CELL cell. This conductive transparent oxide layer also offers good adhesion with epoxy or acrylate based resins that can be found in a low temperature adhesive. In fact, resins of this type adhere two to three times better to a conductive transparent oxide surface than to a metallized surface made from a low-temperature paste.

[0032] Commonly to the embodiments illustrated by [Fig. 1] to [Fig. 5], the cell CELL comprises a first face AV advantageously extending over a surface of the semiconductor stack. The cell CELL also advantageously comprises a second face AR, extending over another surface of the semiconductor stack and opposite the first face AV. The first face AV advantageously constitutes a front face of the cell, that is to say a face intended to receive light radiation. Of course, the first and second faces AV, AR can be swapped, the second face AR possibly being the face intended to receive light radiation.

[0033] The first face AV is advantageously rectangular or pseudo-rectangular and comprises at least a first edge BA. The first edge BA is advantageously the edge covered by an upper cell when the cell CELL is interconnected in a photovoltaic chain of the shingle type. The upper cell then covers a zone of the first AV face called the “covering zone”. The mechanical and electrical interconnection of the cells of the photovoltaic chain is moreover advantageously carried out in the overlap zone. The overlap zone thus extends parallel to the first edge BA less than one overlap length from the first edge BA. In order to reduce the shading caused by the upper cell, the overlap length is advantageously small, that is to say less than or equal to 2 mm, or even less than or equal to 1.5 mm. The improvement in the mechanical interconnection permitted by the cell CELL according to the invention makes it possible in particular to envisage an even shorter overlap length, for example equal to 0.5 mm. [0034] Said first face AV comprises metallizations, also called "conductive tracks" or "discrete electrodes" and described below, the arrangement of which is configured to ensure the collection and routing of the electric currents generated by the cell CELL . The arrangement of said metallizations makes it possible in particular to ensure a robust mechanical connection between the cells of a chain and low resistive losses. However, the arrangement can also be configured to minimize the amount of paste used to make the metallizations. Indeed, the metallizations described below can be produced by screen printing using a low-temperature paste containing, for example, a resin loaded with silver particles. The manufacturing cost of a cell then depends in part on the quantity of low temperature paste used. Also, a judicious arrangement of the metallizations then makes it possible to optimize the quantity of paste used and therefore to lower the manufacturing cost of a CELL cell.

Thus, the first front face AV comprises a first distribution track DIS1, one of whose functions is to centralize the currents collected by means of collection fingers COL (described below) and distribute them to first interconnection conductors INT (also described below). In this sense, the first distribution track is not a collection finger. On the other hand, it can contribute to the collection of electric current in the vicinity of the overlap zone. The first distribution track DIS1 extends parallel to the first edge BA. The first distribution track DIS1 moreover extends over a substantial distance from the first face AV, for example greater than 75% of the length of the first edge BA, or even greater than the length of the first edge BA itself, in particular when the first AV face has a pseudo-rectangular shape. In which case, the length of the first interconnection track DIS1, extending from one side edge to the other of the first face AV, may be greater than the length of said first edge BA. The first distribution track DIS1 can be produced by screen printing a low temperature paste as described previously.

The first distribution track DIS1 extends less than 5 mm from the first edge BA. Preferably, the first track DIS1 extends to less than 4 mm, or even to less than 3 mm. Thus, when the cell CELL is interconnected in a photovoltaic chain, the first distribution track DIS1 can be positioned in the vicinity of the overlap zone. Thus, the necessary length of the first INT interconnect conductors to reach the overlap area can be reduced, notably reducing the amount of conductive ink used.

[0037] The first face AV also comprises a plurality of collection fingers COL ensuring the collection of the electric currents generated by the cell CELL. For this, the collection fingers COL extend parallel to each other and preferentially occupy a large part of the first face AV. In order to allow the routing of electric currents when the cell CELL is interconnected within a chain, the collection fingers COL are electrically connected to the first distribution track DIS1. Thus, the electric currents collected can be distributed to the first interconnection conductors INT by means of the first distribution track DIS1. COL collection fingers can also be made by screen printing a low temperature paste.

The first distribution track DIS1 is responsible for concentrating the electric currents collected by the collection fingers COL and redistributing them to the first interconnection conductors INT. For this, the cell CELL is remarkable in that the width WDIS1 of the first distribution track DIS1 is strictly greater than the width WCOL of each collection finger COL. Thus, the first distribution track DIS1 makes it possible to transport a greater current density than each collection finger COL. The width WCOL of each collection finger COL is advantageously measured perpendicular to the direction in which they extend. The width WDIS1 of the first distribution track DIS1 is advantageously measured perpendicular to the first edge BA. The collection fingers COL can have a width WCOL of between 30 μm and 50 μm. The first distribution track DIS1 can then have a width WDIS1 of between 60 μm and 100 μm.

The cell CELL is also remarkable in that the first face AV also comprises a plurality of first interconnection conductors INT. The first interconnecting conductors INT can advantageously convey the electrical currents collected towards the overlap zone when the cell CELL is interconnected in a chain. They thus make it possible to ensure a reliable electrical interconnection with a superior cell when necessary. For this, said first interconnection conductors INT extend perpendicular to the first edge BA between said first edge BA and the first distribution track DIS1. Each first interconnection conductor INT may moreover have one end disposed less than 2 mm from the first edge BA, or even disposed less than 0.5 mm from the first edge BA, or even disposed on the first edge BA. The more the first interconnection conductors INT extend in the direction of the first edge BA, the easier it is to connect them electrically with an upper cell during an interconnection within a chain. Said first interconnection conductors INT are moreover also electrically connected to the first distribution track DIS1 in order to be able to convey the electric currents.

The first interconnection conductors INT are spaced apart in pairs. Thanks to this, at least a first central free portion LC of the first face AV is delimited at least in part by the first distribution track DIS1, the first edge BA and two first consecutive interconnection conductors INT. Each first central free portion LC is therefore devoid of metallization. As a reminder, the constituent resins or polymers of the so-called "low temperature" adhesives show poor adhesion to the metallizations made from a low temperature paste. Thus, during the interconnection of the CELL cell in a photovoltaic chain, all of the adhesive which is deposited on a first free central portion LC adheres to said first free central portion LC with a high level of adhesion. Adhesion is moreover advantageously improved when the cell CELL comprises a heterojunction semiconductor stack comprising in particular a conductive transparent oxide surface. Indeed, low temperature adhesives show an adhesion two to three times higher on a transparent conductive oxide surface than on a surface metallized with a low temperature paste.

Each first central free portion LC extending between the first edge BA and the first distribution track DIS1, extends at least partly in the overlap zone when the cell CELL is interconnected. Thus, each first central free portion LC can receive a portion of adhesive and participate in the interconnection of the cells within a photovoltaic chain.

[0042] By "at least partially delimited", it is meant that the perimeter of each first central free portion LC comprises at least a portion of the first distribution track DIS1, at least a portion of the first edge BA and two first conductors of consecutive INT interconnection. In other words, every first central free portion LC is arranged between the first distribution track DIS1 and the first edge BA and between two first consecutive interconnection conductors INT.

In order to benefit from a large surface in the overlap zone for each first free central portion LC, it is preferable that the first distribution track DIS1 be placed on the surface of the cell CELL in such a way that it is located outside the overlap zone when the CELL cell is interconnected.

[0044] Commonly to the embodiments illustrated by [Fig. 1], [Fig. 3], [Fig. 4] and [Fig. 5], the collection fingers COL can extend parallel to the first edge BA and therefore parallel to the first distribution track DIS1. In this case, the electrical connection between collection fingers COL and the first distribution track DIS1 can advantageously be made by means of connection elements CONN. The connection elements CONN have the form of wires or ribbons and extend perpendicular to the collection fingers COL and to the first distribution track DIS1. Each connection element CONN is advantageously connected to each collection finger COL, for example by means of a weld located at the intersection between the connection element CONN and a collection finger COL. The connection elements CONN are also transferred to the first distribution track DIS1 to which they can also be connected by means of a localized solder. Thus, the electric currents collected by the collection fingers COL can be routed to the first distribution track DIS1. The CONN connection elements advantageously extend over the first AV face, outside a zone intended to be covered by an upper cell during an interconnection, that is to say more than the covering length of the first edge BA. In fact, in order to reduce the resistive losses, the interconnection elements CONN can have a thickness which can harm the mechanical robustness of the interconnection when the latter are arranged in the overlap zone. In addition, limiting the length of the interconnection elements CONN makes it possible to reduce the consumption of raw materials used in the manufacture of photovoltaic cells, such as copper or silver.

Each connection element CONN is advantageously arranged in the extension of each electrical interconnection conductor INT. In this way, the path traveled by the electric currents from the collection fingers COL up to the INT interconnect conductor is low. Each connection element CONN is advantageously aligned with an interconnection conductor INT.

[0046] According to an embodiment illustrated by [Fig. 2], the collection fingers COL can extend perpendicular to the first edge BA. Thus, it is not necessary to resort to the implementation of connection elements. Indeed, the collection fingers COL are extended as far as the first distribution track DIS1 so as to be connected directly to said first distribution track DIS1. The manufacturing steps are simplified since it is no longer necessary to align and solder the connection elements. On the other hand, this makes it necessary to have collection conductors COL which are not very resistive and therefore require the use of a greater quantity of low temperature paste to carry out the metallization of the cell CELL.

[0047] Commonly to the embodiments illustrated by [Fig. 1] to [Fig. 4], the width WLC of each first central free portion LC is advantageously greater than the pitch PCOL separating the collection fingers COL. The pitch PCOL is advantageously measured between two consecutive collection fingers COL, perpendicular to the direction in which the collection fingers COL extend. The width WLC of each first central free portion LC is advantageously measured parallel to the first edge BA. It corresponds in particular to the gap between the first interconnection conductors INT, the latter being spaced apart two by two. Thus, the greater the width WLC of each first central free portion LC, the more the first central free portion LC can receive adhesive during an interconnection. The mechanical connection with an upper cell is further improved as the dimensions of the adhesive portions increase.

In order to provide wide central free portions LC, the width WLC of each first central free portion LC is advantageously greater than 3 mm and preferably greater than 4.5 mm. The width WLC of each first central free portion LC can for example be equal to 6 mm or 8 mm.

The greater the width WLC of each first central free portion LC, that is to say the greater the gap between the first interconnection conductors INT, and the more the number of first interconnection conductors INT is reduced. with respect to the number of collection fingers COL. In order to reduce the resistive losses due to the lower number of first interconnection conductors INT, it is advantageous to size the width WINT of each interconnection conductor INT so that it can allow circulation without loss of the currents collected by the COL collection fingers.

The widths WDIS1, WINT of the first distribution track DIS1 and of each first interconnection conductor INT advantageously depend on the number of first interconnection conductors INT. When the number of collection fingers COL is much greater than the number of first interconnection conductors INT, there is a high concentration of electric currents in the first distribution track DIS1. Moreover, the electric currents concentrated in the first distribution track DIS1 circulate over greater distances. The first distribution track DIS1 and the first interconnection conductors INT therefore preferably have widths WDIS1, WINT strictly greater than the width WCOL of each collection finger COL. The widths WDIS1, WINT of the first distribution track DIS1 and of the first interconnection conductors INT can advantageously depend on a ratio between the number of collection fingers COL and the number of first interconnection conductors INT. The higher this ratio (to the benefit of the collection fingers) the higher said widths WIDS1, WINT are. The widths WDIS1, WINT of the first distribution track DIS1 and of the first interconnection conductors INT can also depend on the thicknesses of the conductors. Indeed, the collection fingers COL, which are thinner, may have a small thickness which may be slightly less than about ten micrometers. On the other hand, the first distribution track DIS1 and the first interconnection conductors INT, which are wider, may have a greater thickness than the collection fingers COL.

Thus, the first distribution track DIS1 advantageously has a width WDIS1 greater than or equal to twice the width WCOL of each collection finger COL. For example, for a width WCOL of collection fingers COL of between 30 μm and 50 μm, for example 40 μm, the first distribution track DIS1 advantageously has a width WDIS1 of between 60 μm and 100 μm, for example of approximately 80 p.m. Similarly, the width WINT of each first interconnection conductor INT is advantageously greater than or equal to the width WDIS1 of the distribution track DIS1. For example, for a width WDIS1 of the first distribution track DIS1 of between 60 μm and 100 μm, for example 80 μm, each first interconnection conductor INT has a width WINT of between 80 μm and 120 μm, for example 100 μm .

[0053] Commonly to the embodiments illustrated by [Fig. 2] and [Fig. 4], each first interconnect conductor INT comprises an interconnect pattern MOT. The interconnection patterns MOT increase the conductive surface of each first interconnection conductor INT allowing for example to improve the electrical conduction when the cell CELL is interconnected in a chain. For this, the interconnection patterns MOT are preferably arranged on each first interconnection conductor INT, close to the first edge BA, for example less than 1 mm from the first edge BA.

[0054] The interconnection patterns MOT can be solid, as illustrated by [FIG. 2] They thus provide a larger electrical conduction area and reduce the resistivity between the interconnected cells. The MOT interconnect patterns may also comprise a closed contour surrounding a portion of the first face AV, as illustrated by [FIG. 4] They thus provide a larger conduction area compared to the first interconnect conductors INT not comprising a pattern. They also make it possible, thanks to the closed outline, to retain the flow of an uncured portion of adhesive, thus reducing the occurrence of shading due to adhesive drippings on the front and rear faces of the CELL cell. The width WMOT of the interconnection patterns MOT, measured parallel to the first edge BA is greater than the width WINT of the first interconnection conductors INT and preferably greater than twice the width WINT of the first interconnection conductors INT. For example, when a first interconnection conductor INT has a width WINT of 100 μm, the associated pattern MOT may have a width WMOT of 200 μm.

[0055] Commonly to the embodiments of [Fig. 3] and [Fig. 4], the first AV face comprises a second distribution track DIS2 instead of a single and unique first track DIS1 as illustrated by [Figs. 1], [Fig. 2] and [Fig. 5] The first and second distribution tracks DIS1, DIS2 run parallel at the first edge BA. The second distribution track DIS2 preferentially extends between the collection fingers COL and the first distribution track DIS1. In the same way as the first distribution track DIS1, the second distribution track DIS2 extends over a substantial distance from the front face BA, for example greater than 75% of the length of the first edge BA. The two distribution tracks DIS1, DIS2 are moreover preferentially spaced from each other by a distance equal to the pitch PCOL separating the collection fingers COL.

One of the functions of the second distribution track DIS2 is also to achieve the concentration of the electric currents collected so that they can be transmitted to the first interconnection conductors INT. Thus, the collection fingers COL are preferably at least electrically connected to the second distribution track DIS2, the latter being positioned closer to said collection fingers than the first track DIS1. The collection fingers COL can moreover be electrically connected by means of connection elements CONN, stretching perpendicular to the first edge BA and connecting between them the collection fingers COL and the second distribution track DIS2. The first interconnection conductors INT are preferably electrically connected to the first distribution track DIS1, the latter being closer to the first edge BA than the second track DIS2.

So that the collected electric currents can flow from the collection fingers COL to the first interconnection conductors INT, the first and second distribution tracks DIS1, DIS2 are electrically interconnected. The electrical connection between the two tracks DIS1, DIS2 can be made by means of the connection elements CONN then stretching from the first distribution track DIS1 to the collection fingers COL, by connecting the second distribution track DIS2. However, in order to limit the technical complexity of aligning and connecting CONN connection elements, it may be preferable to make the electrical connection between the two distribution tracks by means of a plurality of connecting conductors LIS , as illustrated by [Figs. 3] and [Fig. 4] The LIS connecting conductors extend for example perpendicular to the first edge BA. Moreover, in order to reduce the path traveled by the electric currents in the distribution tracks DIS1, DIS2 and thus reduce the resistive losses, connecting conductors LIS can be arranged in the extension of the first interconnecting conductors INT. It is advantageous for the CONN connection elements to extend at least in part over the LIS connection conductors, as illustrated by [Fig. 3] Thus, the path traveled by the electric currents collected to the first interconnection conductors INT is reduced. The connection elements CONN can then extend over part of an LIS link conductor or over the entire LIS link conductor as far as the first distribution track DIS1.

The LIS connecting conductors can have a width WLIS, measured parallel to the first edge BA, of between 40 μm and 120 μm. The connecting conductors LIS in the extension of the first interconnection conductors INT advantageously have a width WLIS of between 60 μm and 120 μm. The connection conductors LIS remote from the first interconnection conductors INT advantageously have a width WLIS of between 40 μm and 60 μm.

For the same reasons as the first distribution track DIS 1, the second distribution track DIS2 has a width WDIS2, measured perpendicular to the first edge BA, strictly greater than the width WCOL of each collection finger COL. Preferably, the widths WDIS1, WDIS2 of the first and second distribution tracks DIS1, DIS2s are preferably equal. [0061] Whether the first AV face includes one or two distribution tracks

DIS1, DIS2, the central free portions remain delimited by the first distribution track DIS1, the first edge BA and two first consecutive interconnection conductors INT.

The cell CELL advantageously comprises a second face AR, opposite the first face AV. The first face AV may correspond to a front face of the cell CELL, likely to be exposed to solar radiation so that the cell CELL can supply electrical energy. According to another example, the second face AR can correspond to a front face and be directly exposed to solar radiation or correspond to a rear face and be exposed to solar radiation by reflection of the radiation on a surface having a high albedo. According to this last example, the second face AR can also have metallizations allowing the radiation to reach the surface of the cell CELL and collect the electric currents generated. The second face AR then advantageously comprises metallizations of the same nature as the first face AV, making it possible in particular to improve the mechanical connection of said cell CELL when the latter is interconnected in a chain.

For this, the second rear face, an embodiment of which is illustrated by [Fig. 6], advantageously comprises a second edge BR, opposite the first edge BA. For the sake of clarity and unless otherwise stated, the thickness of the cell CELL, measured perpendicularly to the first and second faces AV, AR is neglected in the description and the associated figures. Also the edges of the first AV face coincide with the edges of the second AR face.

The second face AR advantageously comprises a third distribution track DISR extending parallel to the second edge BR.

The second face AR also advantageously comprises a plurality of second interconnection conductors INTR being electrically connected to the third distribution track DISR. Each second interconnection conductor INTR extends perpendicular to the second edge BR, between said second edge BR and the third distribution track DISR. In the same way as the first distribution track DIS1, the third conductive track DISR ensures the concentration of the electric currents collected at the level of the second face AR by collection fingers and the distribution of said currents towards the second interconnection conductors INTR. For this, the width of the third conductive track DISR is advantageously equal to the width WDIS1 of the first distribution track DIS1.

The third distribution track DISR, the second edge BR and two second consecutive interconnection conductors INTR thus make it possible to delimit at least a second free central portion LCR of the second face AR. Each second central free portion LCR is thus devoid of metallizations, in the same way as each first free central portion LC, making it possible to offer improved adhesion with a low-temperature adhesive when the cell CELL is interconnected in a chain. The second interconnection conductors INTR are also advantageously spaced apart in pairs. The distance between the second interconnection conductors INTR two by two is preferably greater than the pitch separating the collection fingers extending on the second face AR. Said distance separating the collection fingers can for example be 0.7 mm, in which case the distance between the second interconnection conductors INTR two by two is advantageously greater than 0.7 mm, for example equal to 3 mm. In order to facilitate the interconnection between two cells CELL according to the invention, it is advantageous for the distance separating the second interconnection conductors INTR two by two to be identical to the distance separating the first interconnection conductors INT two by two. Thus, the width of each second free central portion LCR, measured parallel to the second edge BR, is equal to the width WLC of each first free central portion LCR, measured parallel to the first edge BA. In this way, the connection of the first face of a first cell CELL according to the invention and of the second face of a second cell CELL according to this example makes it possible to take maximum advantage of the first and second central free portions LC, LCR . The adhesion of a portion of adhesive to a central free portion will not be limited by the size of the other central free portion. In addition, it is advantageous that each second interconnect conductor INTR is aligned with a first interconnect conductor INT. In this way, the first and second central free portions LC, LCR are aligned and opposed to each other. Thus, it is possible to position two CELL cells according to the invention partially overlapping so that their first and second central free portions LC, LCR face each other.

[0069] According to an embodiment illustrated by [Fig. 5], the first face AV comprises a side edge BL extending from the first edge BA. The side edge BL can be straight or curved. In the first case, when the side edge BL is straight, it can form a rectangular cell edge. In the second case, when the lateral edge BL is curved, it can form a pseudo-rectangular cell edge called “pseudo-square” in English. It is in particular this second case which is illustrated by [FIG. 5] In this case, the side edge BL describes an arc starting from the first edge BA. The side edge BL may correspond to an edge of an ingot in which the photovoltaic cell is cut. A lateral free portion LL can be delimited in part by the first distribution track DIS1, the first edge BA and the lateral edge BL and a first consecutive interconnecting conductor INT of the side edge BL. The lateral free portion LL can thus accommodate a portion of adhesive in order to contribute to the mechanical connection with an upper cell in a photovoltaic chain. The lateral free portion LL thus has a width WLL, measured parallel to the first edge BA, equal to the distance between the first consecutive interconnection conductor INT of the lateral edge BL and said lateral edge BL. The distance is measured from the end of the first consecutive edge BA of the side edge BL and the first interconnecting conductor INT.

[0070] The [Fig. 7] illustrates an embodiment of a method of manufacturing 10 of a cell according to the invention. The manufacture 10 of the cell comprises a first step 11 of forming on a first face of a substrate: a first distribution track extending parallel to a first edge and less than 5 mm from the first edge; and a plurality of collection fingers extending parallel to each other, said collection fingers being electrically connected to the first distribution track, the width of the first distribution track being strictly greater than the width of each collection finger.

[0071] The first distribution track and the collection fingers can be screen-printed using a paste comprising a resin and metallic particles.

The manufacture 10 of the cell also comprises a second step 12 of forming on the first face of the substrate: a plurality of first interconnection conductors, said first interconnection conductors being electrically connected to the first distribution track and extending perpendicular to the first edge between said first edge and the first distribution track, the first interconnection conductors being spaced apart in pairs; and at least a first central free portion of the first face being delimited at least in part by the first distribution track, the first edge and two first consecutive interconnection conductors. The first interconnection conductors can also be screen-printed using a paste comprising a resin and metal particles.

The first and second forming steps 11, 12 are advantageously carried out simultaneously.

[0075] The [Figs. 8] to [Fig. 13] illustrate different embodiments of an STR photovoltaic chain according to the invention. The photovoltaic chain 30, which will also be simply called STR chain, is an assembly of photovoltaic cells interconnected two by two so as to create an electrical and mechanical connection. The STR chain is of the "shingle" or "shingle" type, i.e. the cells partially overlap two by two, a zone of the rear face of an upper cell being electrically and mechanically connected to a zone of the front face of a lower cell. The robustness of the STR chain is notably improved thanks to the implementation of a cell according to the invention.

For this, in common to the embodiments of [Fig. 8] to [Fig. 13], the STR chain is remarkable in that it comprises: a first photovoltaic cell CELL1 according to the invention as described previously; a second photovoltaic cell CELL2, which can be a cell according to the invention or a cell according to the prior art; and at least a first portion of ADH adhesive.

The first and second cells CELL1, CELL2 are interconnected with one another in a shingle, an AR' face of the second cell CELL2 partially covering the first AV face of the first photovoltaic cell CELL1. The second cell CELL2 is therefore the upper cell of the shingle and the first cell CELL1 is therefore the lower cell of the shingle. The dotted lines in [Fig. 8] and [Fig. 12] represent elements hidden by the second cell CELL2.

The second cell CELL2 is linked to the first cell CELL1 by means of each first portion of adhesive ADH. Each first portion of adhesive ADH adheres to a first central free portion LC of the first AV face of the first photovoltaic cell CELL1 and to the face AR' of the second photovoltaic cell CELL2.

[0079] By the term “linked”, it is meant that the first and second cells are mechanically connected in a rigid manner.

So that the shading of one cell over the other is minimal, the second cell CELL2 covers the first cell CELL1 by preferentially covering the first edge BA of the first face AV of the first cell CELL1. The second cell CELL2 then covers a zone of the first AV face called the “covering zone”. The overlap zone therefore extends over the first face AV from the first edge BA to an overlap length REC from the first edge BA. The mechanical and electrical interconnection of the cells CELL1, CELL2 is moreover advantageously made in the overlap zone, that is to say at less than the overlap length REC of the first edge BA.

The face AR' of the second cell CELL2 comprises an edge BR' located directly above the first cell CELL1 when the two cells CELL1, CELL2 are interconnected. The overlap zone then extends between the first edge BA of the first face AV of the first cell CELL1 and the edge BR' of the face AR' of the second cell CELL2. The edge BR' of the face AR' of the second cell CELL2 preferentially extends parallel to the first edge BA of the first face AV of the first cell CELL1.

The shading of the second cell CELL2 on the first cell CELL1 is lower the lower the overlap length REC. The overlap length REC is moreover less than 2 mm, or even less than 1.5 mm. On the other hand, it may be more difficult to manufacture a robust chain with an REC lap length of less than 1 mm. Indeed, the lap length of a shingle type chain is mainly limited by the robustness of the mechanical connection between the cells. The chains can be subjected to high mechanical stresses, for example during their manufacture, tending to arch them. The forces applied to the chain are therefore transferred to the level of the interconnections between the cells, where the mechanical connection is the weakest. The improvement in the robustness of the mechanical connection made possible by the cell CELL1 according to the invention makes it possible to reduce the overlap length REC, by example less than 1 mm, or even less than or equal to 0.5 mm, while ensuring good mechanical reliability of the STR chain.

[0083] In order to minimize the shading and therefore the overlap length REC, each first portion of adhesive ADH is advantageously placed on a first central free portion LC of the first face AV, less than the overlap length REC of the first edge BA. Thus, the amount of adhesive used is limited and participates fully in the mechanical connection. The level of mechanical connection greatly depends on the dimensions of each first portion of adhesive ADH used and more particularly their length LADH, measured parallel to the first edge BA, and their width WADH, measured perpendicular to the first edge BA. When each first portion of adhesive ADH adheres over the entire region of each central free portion LC extending less than the length of overlap REC of the first edge BA, then the solidity of the connection between the cells is maximum. In other words, each first portion of adhesive ADH can extend at most over the width WLC of a first central free portion LC. In the same way, each first portion of adhesive ADH can extend at most over the entire length of covering REC.

However, it may be advantageous to reduce the length and/or the width of the first portion of adhesive in order to reduce the amount of adhesive used. It is also advantageous for each first portion of adhesive ADH to be in contact only with the surface of the first cell CELL1 and not with metallized surfaces. It is therefore preferable for the length LADH of each first portion of adhesive ADH to be strictly less than the width WLC of the first free portion over which it extends.

Furthermore, the first face AV of the first cell CELL1 can also comprise a plurality of second portions of adhesive ECA making it possible to make the electrical connection between the first interconnection conductors INT and the second cell CELL2. It is therefore advantageous to further reduce the length of the first portions of adhesive ADH to make it possible to position the second portions of adhesive ECA. This approach is moreover preferred when the first portions of ADH adhesive are electrically non-conductive. It is then advantageous that the first and second portions of adhesive ADH, ECA do not mix so as not to reduce the electrical conductivity between the first and second cells CELL1, CELL2.

Preferably, each first portion of adhesive ADH is remote from each first interconnection conductor INT. In this way, the quantity of adhesive implemented for each first portion of adhesive ADH is then entirely in contact with a surface free of metallization. Adhesion is therefore optimal. In addition, the space between the first portion of adhesive ADH and each first interconnection conductor INT makes it possible to contain the creep of the portion ADH when the second cell CELL2 is pressed against said portion ADH.

The distance W between each first portion of adhesive ADH and each first interconnection conductor INT is advantageously measured parallel to the first edge BA, as illustrated by [Figs. 9] and [Fig. 10]

Each first portion of adhesive ADH is advantageously at least 0.5 mm from each first interconnection conductor INT. Thus, the second portions of adhesive ECA can be positioned on each first interconnection conductor INT without being in contact with a first portion of adhesive ADH. For example, for a width WLC of first central free portion LC of 4.5 mm, the length LADH of each first portion of adhesive ADH is then advantageously less than or equal to 3.5 mm. For a width WLC of first central free portion LC of 8 mm, the length LADH of each first portion of adhesive ADH is then advantageously less than or equal to 7 mm.

It may be advantageous to increase the distance between each first portion of adhesive ADH and each first interconnection conductor INT in order to improve the positioning margins of the first and second portions of adhesive ADH, ECA. Each first portion of adhesive ADH can be separated by at least 2 mm from each first interconnection conductor INT. In this way, for a width WLC of first central free portion LC of 8 mm, the length LADH of each first portion of adhesive ADH is then advantageously less than or equal to 4 mm.

When the first cell CELL1 has a dimension of 156 mm by 26 mm, it can comprise for example respectively 19 and 17 first central free portions LC of 8 mm along the longest edge, depending on whether it is rectangular or pseudo-rectangular. The STR chain can show improved reliability thanks to a first portion of adhesive ADH having a length LADH of 4 mm on each first free central portion LC.

When the first cell CELL1 has a dimension of 156 mm by 26 mm, it can comprise for example respectively 51 and 45 first central free portions LC of 3 mm along the longest edge, depending on whether it is rectangular or pseudo -rectangular. The STR chain can show improved reliability thanks to a first portion of adhesive ADH having a length LADH of 1 mm on each first free central portion LC.

In order to further reduce the quantity of adhesive used, it is also advantageous to reduce the width WADH of each first portion of adhesive ADH. The width WADH of each first portion of adhesive ADH is advantageously less than the overlap length REC. In this way, adhesion is optimal. However, a flow of the non-crosslinked adhesive can extend outside the overlapping zone, for example on the exposed surface of the first cell CELL1. When the adhesive is transparent, the impact on the performance of the STR chain is small. On the other hand, when the adhesive is opaque, the drop in yield of the STR chain can be substantial. When the adhesive is electrically conductive, it can cause a short-circuit of one of the two cells CELL1, CELL2.

It is then advantageous for each first portion of adhesive ADH to be distant from each edge of the first and second cells CELL1, CELL2. Each first portion of adhesive ADH being placed at the level of the overlap zone, it is then advantageous for each first portion of adhesive ADH to be distant from the first edge BA of the first photovoltaic cell CELL1 and from the edge BR' of the second cell photovoltaic CELL2. Thus, each first portion of adhesive ADH is placed in the overlap zone and has a space with the edges BA, BR' of the first and second cells CELL1, CELL2 making it possible to contain a flow of adhesive.

It is advantageous for the distance between each first portion of adhesive ADH and each edge BA, BR' to depend on the tolerances achievable by screen printing. Screen printing equipment offers a positioning tolerance of the studs of adhesive in the order of 0.05 mm. It is then advantageous for each first portion of adhesive ADH to be at least 0.05 mm from each edge BA, BR' of the first and second cells CELL1, CELL2.

Thus, for an overlapping length REC of 0.5 mm, each first portion of adhesive ADH may have a width WADH less than or equal to 0.4 mm, for example equal to 0.35 mm. In the latter case, the positioning tolerance between the first edge BA of the first cell CELL1 and the edge BR' of the second cell CELL2 is 0.075 mm on either side of each first portion of adhesive ADH.

Thus, thanks to the invention, the overlap length REC and the associated shading can be greatly reduced while providing a robust mechanical connection of the chain STR.

[0097] Advantageously, the STR chain, illustrated by [Fig. 10], comprises a plurality of first portions of adhesive ADH adhering to a first central free portion LC. Thus, and for the reasons presented previously, the length LADH of each first portion of adhesive ADH placed on a first central free portion LC is preferably chosen so that each first portion of adhesive ADH is distant from each first interconnection conductor INT.

The adhesive used to form each first ADH portion preferably comprises an epoxy- or acrylate-based resin. On the other hand, it is not necessary for this adhesive to comprise metallic particles in order to make it conductive. Indeed, the first portions of ADH adhesive do not participate in electrical conduction, it is then advantageous, in particular in terms of manufacturing cost and saving of raw materials, that each first portion of ADH adhesive is non-conductive. electrically, i.e. electrically insulating. However, in order to simplify the manufacturing steps of the STR chain, it can also be envisaged to use the same adhesive to make the mechanical and electrical connection (described below). In which case, the adhesive can be electrically conductive and each first portion of ADH adhesive can then be electrically conductive.

[0099] Commonly to the embodiments illustrated by [Fig. 9] to [Fig. 13], the STR chain comprises a plurality of second portions of ECA adhesive, each second portion of adhesive ECA adheres to a zone of each first interconnection conductor INT of the first face AV of the first cell CELL1. Each second portion of adhesive ECA also adheres to the face AR' of the second cell CELL2. The second portions of adhesive ECA participate in the electrical interconnection of the chain STR, for this they are electrically conductive. They can for example be made using an electrically conductive adhesive, comprising for example a resin loaded with metal particles, such as silver particles.

[00100] The second portions of adhesive ECA are advantageously positioned in the overlap zone, that is to say less than the overlap length REC of the first edge BA. In this way, all of the electrically conductive adhesive, implemented to form the second portions of adhesive ECA, participates in the electrical interconnection of the chain STR. In order to reduce the resistive losses at the level of the overlap zone, it is advantageous for the second portions of adhesive ECA to extend over interconnection patterns MOT, as illustrated by [Figs. 10] and [Fig. 11] In fact, the MOT interconnection patterns offer a larger metallized surface making it possible to improve the electrical connection.

[00101] The second portions of adhesive ECA participate only slightly, or even not at all, in the mechanical connection with the second cell CELL2, it is therefore not necessary for them to have a large surface area. Each second portion of adhesive ECA advantageously covers the width WINT of a first interconnection conductor INT and preferably the width WMOT of an interconnection pattern MOT. For this, each second portion of ECA adhesive may have an LECA length of between 0.9 mm and 2 mm. Thus, the length LECA of each second portion of adhesive ECA, measured parallel to the first edge BA, is advantageously less than the length LADH of each first portion of adhesive ADH. In this way, the amount of electrically conductive adhesive used is reduced.

[00102] In order to limit the risk of mixing between the first and second ADH and ECA adhesives, each first portion of ADH adhesive is separated from each second portion of ECA adhesive. Thus, each first and second portions of adhesive ADH, ECA are separated by a safety space providing a positioning tolerance and making it possible to contain any flow of adhesive. It is advantageous to size the LADH length of each first potion of ADH adhesive according to the LECA length of each second portion of ECA adhesive and vice versa. For example, each first portion of ADH adhesive is spaced at least 0.1 mm from each second portion of ECA adhesive. In the example illustrated by [Fig. 10], the first cell CELL1 may comprise a first central free portion LC having a width of 8 mm, first interconnection conductors INT comprising interconnection patterns MOT having a width of 0.5 mm. Said cell CELL1 can advantageously comprise second portions of adhesive ECA having a length LECA of 0.9 mm and a first portion of adhesive ADH having a length LADH of 6 mm.

[00103] In order to further reduce the quantity of raw material used during the interconnection of the STR chain, the WECA width of each second portion of ECA adhesive, illustrated by [FIG. 9], can advantageously be less than the width WADH of each first portion of adhesive ADH. It advantageously depends on the overlap length REC. When the lap length REC is equal to 0.5 mm, the width WECA of each second portion of adhesive ECA can be between 0.15 mm and 0.3 mm.

[00104] On the other hand, to reduce the resistive losses at the level of the interconnection, it is advantageous for each second portion of adhesive ECA then to extend over a large part of each first interconnection conductor INT positioned in the zone of recovery. However, in order to avoid a flow of electrically conductive adhesive out of the overlap zone, it is advantageous for each second portion of adhesive ECA to be distant from the edges of each cell CELL1, CELL2, for example by at least 0, 05 mm and preferably at least 0.1 mm. Thus, when the lap length REC is equal to 0.5 mm, the width WECA of each second portion of adhesive ECA is advantageously between 0.15 mm and 0.4 mm, advantageously between 0.15 mm and 0 .3mm. For example, the width WADH of a first portion of adhesive ADH can be equal to 0.350 mm and the width WECA of a second portion of adhesive ECA can be equal to 0.250 mm.

The second cell CELL2 can be a cell according to the prior art or according to the invention. For example, when the second cell CELL2 is a cell according to the prior art, it can comprise metallizations on the face AR' covering the first cell CELL1. It can be a full plate metallization, covering the entirety of its face AR' or of a discrete electrode arranged at the level of the overlap zone. These metallizations ensure electrical continuity when the first and second cells CELL1, CELL2 are interconnected. However, in order to improve the robustness of the mechanical connection between the two cells, it is advantageous for the second cell CELL2 to be able to offer a free portion of its face AR' making it possible to increase the level of adhesion of the first portions of adhesive ADH with said face AR'. Thus, the second cell CELL2 can advantageously be a cell according to the invention offering a central free portion. The face AR' of the second cell CELL2 can correspond to its rear face, so it is particularly advantageous for the second cell CELL2 to include metallizations as described by [FIG. 6] Thus, the second cell CELL2 then comprises at least a second central free portion LCR to contact with a first portion of adhesive ADH placed on a first free central portion LC of the first cell CELL1.

[00106] However, without necessarily being a cell according to the invention, the second cell CELL2 can comprise a plurality of discrete electrodes ED preferably extending perpendicularly to the first edge BA of the first cell CELL1. When the second cell CELL2 is a cell according to the invention, it can then be the second interconnection conductors INTR extending on the face AR'. When the second cell CELL2 is a cell according to the prior art, it may be conductive tracks, such as collection fingers, extending on the face AR' and at least partly in the overlap zone. In order to provide robust adhesion, the discrete electrodes ED are advantageously spaced apart two by two by a distance equal to the width WLC of the first central free portion LC of the first cell CELL1. In this way, no metallization significantly reduces the free surface of any metallization of the first central free portion LC, and therefore no metallization reduces the level of adhesion of each first portion of adhesive ADH on the face AR ' of the second cell CELL2. The discrete electrodes ED can be aligned with the first interconnection conductors INT, in this way the dimensions of the second portions of adhesive ECA can be reduced, the distance between an interconnection conductor INT and the associated electrode ED being reduced. By the term "aligned" is meant that each discrete electrode ED can be superimposed on a first interconnection conductor INT when the tiles are superimposed.

[00107] However, the alignment of the discrete electrodes ED with the first interconnection conductors INT tends to increase the space Z between the first face AV of the first cell CELL1 and the face AR' of the second cell CELL2. Indeed, the discrete electrodes ED and the first interconnection conductors INT have a thickness that can be between 10 μm and 20 μm. The space Z between the two faces AV, AR', measured perpendicular to said faces, can then be between 20 μm and 40 μm. The quantity of adhesive to be used to produce each first portion of adhesive ADH is greater the greater the space Z between the faces AV, AR'. In order to reduce the quantity of adhesive used, the discrete electrodes ED are advantageously misaligned with respect to each first interconnection conductor INT as illustrated by [FIG. 13] By the term “misaligned”, it is meant that each discrete electrode ED does not overlap on a first interconnection conductor INT. In other words, each discrete electrode ED is spaced from each first interconnect conductor INT. The pitch between the first interconnection conductors INT can be equal to the pitch between the discrete electrodes ED, on the other hand the discrete electrodes ED are preferentially translated parallel to the first edge BA by a distance comprised between 50 μm and 300 μm. Each discrete electrode ED is thus at least 50 μm to 300 μm from a first interconnection conductor INT. In this way, the discrete electrodes ED are not facing the first interconnection conductors INT and the space Z between the faces AV, AR' can be reduced. The quantity of adhesive necessary to form the first portions of adhesive ADH can then be reduced, for example by half. The length LECA of each second portion of adhesive ECA is, on the other hand, advantageously increased to make it possible to connect a first interconnection conductor INT with a discrete electrode ED. The length of each second portion of ECA adhesive can for example be between 500 μm and 1500 μm.

[00108] The [Fig. 11] illustrates an embodiment of the STR chain comprising a first cell CELL1 having a shape of the pseudo-rectangle type. That is to say that the first face AV includes a side edge BL from the first edge BA. The first front face illustrated by [Fig. 11] notably comprises a free portion lateral LL, described in more detail by [Fig. 5] In order to reinforce the mechanical connection between the first and second cells CELL1, CELL2, a first portion of adhesive ADH is advantageously placed at the level of the lateral free portion LL, adhering to the lateral free portion LL and to the face AR' of the second CELL2 photovoltaic cell. For the same reasons as explained above, the first portion of ADH adhesive used is preferably electrically non-conductive.

[00109] The first portion of adhesive ADH deposited at the free side portion LL is advantageously distant from the first consecutive interconnection conductor INT of the lateral edge BL and is also advantageously distant from the lateral edge BL. The length LADH of the first portion of adhesive ADH is in this case less than the width WLL of the lateral free portion LL. In order to simplify the production of the first portions of adhesive ADH, each portion of adhesive advantageously has the same width WADH, whether it is deposited at a first free central portion LC or at the free lateral portion LL.

[00110] The [Fig. 14] illustrates one mode of implementation of a method of manufacturing a chain according to the invention.

[00111] The manufacture 20 of the chain firstly comprises the provision 21 of a first cell according to the invention, a second cell and at least a first portion of adhesive.

Next, the manufacture 20 of the chain then comprises the deposition 22 of each first portion of adhesive on a first central free portion of the first face of the first photovoltaic cell. Each first portion of adhesive can be screen printed from an epoxy or acrylate based resin. In order to facilitate the production of the deposit 22, the adhesive used advantageously has a rheology allowing it to be screen printed in a well-defined pattern with a limited enlargement vis-à-vis the open pattern in the screen printing screen, for example exhibiting an enlargement less than or equal to 50 μm.

[00113] An alternative implementation of the deposition 22 comprises the deposition of the first and second portions of adhesive simultaneously. When the first portions of adhesive are non-conductive, it may be difficult to screen-print them simultaneously. For this, the first portions of adhesive can be deposited on the first face of the first cell while the second portions of electrically conductive adhesive are deposited on the second face of the second cell. This imposes a reversal of the second cell between the two deposits and the use of a grooved screen printing table to avoid contact of a first portion of adhesive with a second portion of adhesive. Another alternative implementation comprises the deposition of adhesives without contact, for example by depositing each first portion of adhesive by inkjet.

[00114] Finally, the manufacture 20 of the chain comprises the connection 23 of the second cell to the first cell by means of each first portion of adhesive, one face of the second cell partially covering the first face of the first cell, each first portion of adhesive adhering to a first central free portion of the first face of the first cell and to the face of the second cell.

Claims

[Claim 1] Photovoltaic cell (CELL) comprising a first face (AV), said first face (AV) comprising:

- a first edge (BA);

- a first dispensing track (DIS1) extending parallel to the first edge (BA) and less than 5 mm from the first edge (BA);

- a plurality of collection fingers (COL) extending parallel to each other, said collection fingers (COL) being electrically connected to the first distribution track (DIS1); the photovoltaic cell being characterized in that:

- the width (WDIS1) of the first distribution track (DIS1) is strictly greater than the width (WCOL) of each collection finger (COL); and in that

- the first side (AV) also includes:

- a plurality of first interconnect conductors (INT), said first interconnect conductors (INT) being electrically connected to the first distribution track (DIS1) and extending perpendicular to the first edge (BA) between said first edge ( BA) and the first distribution track (DIS1), the first interconnection conductors (INT) being spaced apart in pairs; and

- at least a first central free portion (LC) of the first face (AV) delimited at least in part by the first distribution track (DIS1), the first edge (BA) and two first consecutive interconnection conductors (INT) .

[Claim 2] Photovoltaic cell (CELL) according to the preceding claim, characterized in that the collection fingers (COL) extending parallel to the first edge (BA) and in that the collection fingers (COL) are electrically connected to the first distribution track (DIS1) by means of connection elements (CONN) in the form of wires or strips extending perpendicularly to the first edge (BA), each connection element (CONN) being preferably arranged in the extension of each first interconnect conductor (INT).

[Claim 3] Photovoltaic cell (CELL) according to one of the preceding claims, characterized in that the width (WLC) of each first central free portion (LC) is greater than the pitch (PCOL) separating the collection fingers (COL) .

[Claim 4] Photovoltaic cell (CELL) according to one of the preceding claims, characterized in that the width (WDIS1) of the first distribution track (DIS1) is greater than or equal to twice the width (WCOL) of each finger of collection (COL).

[Claim 5] Photovoltaic cell (CELL) according to one of the preceding claims, characterized in that the width (WINT) of each first interconnection conductor (INT) is greater than or equal to the width (WDIS1) of the first track distributor (DIS1 ).

[Claim 6] Photovoltaic cell (CELL) according to one of the preceding claims, characterized in that the first interconnection conductors (INT) each comprise an interconnection pattern (MOT).

[Claim 7] Photovoltaic cell (CELL) according to one of the preceding claims, characterized in that the first face (AV) comprises a second distribution track (DIS2) extending parallel to the first edge (BA) between the first track distribution (DIS1) and the collection fingers (COL), the second distribution track (DIS2) being electrically connected to the first distribution track (DIS1) and preferably by means of a plurality of connecting conductors (LIS) s each extending perpendicularly to the first edge (BA), the width (WDIS2) of the second distribution track (DIS2) being greater than the width (WCOL) of each collection finger (COL) and preferably equal to the width (WDIS1) of the first distribution track (DIS1 ).

[Claim 8] Photovoltaic cell (CELL) according to one of the preceding claims, characterized in that it comprises a second face (AR) opposite the first face (AV), said second face (AR) comprising:

- a second edge (BR), opposite the first edge (BA);

- a third distribution track (DISR) extending parallel to the second edge (BR);

- a plurality of second interconnecting first conductors (INTR) being electrically connected to the third distribution track (DISR) and extending perpendicular to the second edge (BR) between said second edge (BR) and the third distribution track (DISR), the second interconnection conductors (INTR) being spaced apart in pairs; and

- at least a second central free portion (LCR) delimited in part by the third distribution track (DISR), the second edge (BR) and two consecutive second interconnection conductors (INTR).

[Claim 9] Photovoltaic cell (CELL) according to one of the preceding claims, characterized in that it comprises a semiconductor stack, said semiconductor stack preferably being heterojunction.

[Claim 10] Photovoltaic chain (STR) characterized in that it comprises:

- a first photovoltaic cell (CELL1) according to one of the preceding claims;

- a second photovoltaic cell (CELL2); and

- at least a first portion of adhesive (ADH), said second photovoltaic cell (CELL2) being linked to the first photovoltaic cell (CELL1) by means of each first portion of adhesive (ADH), one face (AR ¹ ) of the second photovoltaic cell (CELL2) partially covering the first face (AV) of the first photovoltaic cell (CELL1), each first portion of adhesive (ADH) adhering to a first central free portion (LC) of the first face (AV) of the first photovoltaic cell (CELL1) and to the face (AR ¹ ) of the second photovoltaic cell (CELL2).

[Claim 11] Photovoltaic chain (STR) according to the preceding claim, characterized in that each first portion of adhesive (ADH) is remote from each first interconnection conductor (INT) of the first face (AV) of the first cell photovoltaic (CELL1) and preferably at least 0.5 mm apart from each first interconnection conductor (INT) of the first face (AV) of the first photovoltaic cell (CELL1).

[Claim 12] Photovoltaic chain (STR) according to one of the two preceding claims, characterized in that a plurality of first portions of adhesive (ADH) adhere to the first central free portion (LC) of the first face (AV ) of the first photovoltaic cell (CELL) and to the face (AR ¹ ) of the second photovoltaic cell (CELL2).

[Claim 13] Photovoltaic chain (STR) according to one of the three preceding claims, characterized in that the face (AR ¹ ) of the second photovoltaic cell (CELL2) comprises an edge (BR ¹ ) plumb with the first face (AV) of the first photovoltaic cell (CELL1), each first portion of adhesive (ADH) being remote from the first edge (BA) of the first face (AV) of the first photovoltaic cell (CELL1) and from the edge (BR ¹ ) from the face (AR ¹ ) of the second photovoltaic cell (CELL2) and preferably at least 0.05 mm from the first edge (BA) of the first face (AV) of the first photovoltaic cell (CELL1) and from the edge (BR ¹ ) of the face (AR ¹ ) of the second photovoltaic cell (CELL2).

[Claim 14] Photovoltaic chain (STR) according to one of the four preceding claims, characterized in that it comprises a plurality of second portions of electrically conductive adhesive (ECA), each second portion of adhesive (ECA) electrically connecting a first interconnection conductor (INT) from the first face (AV) of the first photovoltaic cell (CELL1) to the face (AR ¹ ) of the second photovoltaic cell (CELL2).

[Claim 15] Photovoltaic chain (STR) according to the preceding claim, characterized in that the length (LADH) of each first portion of adhesive (ADH) is greater than the length (LECA) of each second portion of adhesive (ECA ).

[Claim 16] Photovoltaic chain (STR) according to one of the two preceding claims, characterized in that the width (WADH) of each first portion of adhesive (ADH) is greater than the width (WECA) of each second portion of adhesive (ECA).

[Claim 17] Photovoltaic chain (STR) according to one of the three preceding claims, characterized in that the face (AR ¹ ) of the second photovoltaic cell (CELL2) comprises a plurality of discrete electrodes (ED) spaced from each first interconnection conductor (INT) of the first face (AV) of the first photovoltaic cell (CELL1), each second portion of adhesive (ECA) connecting a first interconnection conductor (INT) to a discrete electrode (ED).