WO2025068563A1 - Photovoltaic module with a flexible interconnection structure - Google Patents

Abstract

The invention relates to a photovoltaic module, and to a method for producing same, comprising a step of producing a flexible interconnection structure (8) according to the following steps: - producing a routing film comprising a structural film (11), at least one conductive routing track (9A) on one face of the structural film (11), and at least one other conductive routing track (9B) on the other face of the structural film (11); - forming at least two connection regions (14) on a portion of a conductive routing track (9A, 9B); - for each connection region (14), creating a fold adjacent to the connection region (14), wherein the operations for placing the rear face layers further comprise the following steps: - positioning the flexible interconnection structure (8) on the rear face of the photovoltaic cells (4); - electrically connecting the connection regions (14).

Description

DESCRIPTION

Title: Photovoltaic module with flexible interconnection structure

TECHNICAL FIELD

The invention relates to the field of photovoltaic energy. More specifically, the invention relates to the fields of research on the electrical architecture of photovoltaic modules, such as solar panels, on the arrangement of cells within these photovoltaic modules, and on the associated manufacturing processes.

EARLIER ART

Photovoltaic modules, such as currently available solar panels, are generally produced by implementing encapsulation of an array of photovoltaic cells through front-side layer and back-side layer placement operations.

In fact, a photovoltaic module comprises a skeleton of cells in which the cells are connected to each other according to a predetermined electrical architecture, and this skeleton of cells is associated with:

- front face layers, which generally comprise various layers of encapsulating materials as well as, for example, tempered glass forming the external surface of the photovoltaic module on its front face;

- rear face layers which also include layers of encapsulating materials, in particular to electrically and mechanically insulate the photovoltaic cells from the exterior and protect the rear face of the photovoltaic module.

One of the major areas of research in the field of photovoltaic modules is increasing their efficiency, and in particular the management of behavior under partial shading. Current electrical architectures of photovoltaic modules tend to become more complex to improve resilience to current imbalances between cells, due to partial shading or degradation phenomena. These complex electrical cell architectures may require appropriate cell arrangements, for example staggered cell arrangements, or arrangements providing offsets between adjacent cells by a certain pitch. These arrangements can increase the cost of photovoltaic modules and degrade their cell density.

Another major area of research in the field of photovoltaic modules is the integration of these modules into multiple applications, particularly embedded applications. For example, the design of photovoltaic modules intended for applications such as automobiles faces significant integration constraints, given the shapes and spaces available on bodywork.

STATEMENT OF THE INVENTION

The invention aims to improve the photovoltaic modules of the prior art by improving both the integration capabilities and the performances under shading.

To this end, the invention relates to a method for producing a photovoltaic module, implementing an encapsulation of a network of photovoltaic cells by operations of placing front face layers and rear face layers. In this method, the operations of placing rear face layers comprise the production of a flexible interconnection structure according to the following steps:

- producing a routing film comprising: a structural film which is electrically insulating and has a predetermined area covering a predetermined interconnection pattern of the photovoltaic cells; at least one conductive routing track formed from a layer of conductive material on one of the faces of the structural film; and at least one conductive routing track formed from a layer of conductive material on the other face of the structural film;

- forming at least two connection zones for each conductive routing track, by making through-cuts in the routing film, each through-cut delimiting a connection zone on a portion of a conductive routing track;

- for each connection area, make a fold adjacent to the connection area so that the connection area is facing in the same direction as the corresponding conductive routing track, and in an opposite direction. The operations of placing back face layers also include the following steps:

- install said flexible interconnection structure on the rear face of the photovoltaic cells;

- electrically connecting the connection areas of the flexible interconnection structure to the photovoltaic cells, following the predetermined photovoltaic cell interconnection pattern.

According to another object, the invention relates to a photovoltaic module comprising an array of photovoltaic cells encapsulated between front face layers and rear face layers. This photovoltaic module comprises a flexible interconnection structure arranged on the rear face of the photovoltaic cells, and comprising:

- a structural film which is electrically insulating and has a predetermined area covering a predetermined pattern of interconnection of the photovoltaic cells;

- at least one conductive routing track formed from a layer of conductive material on one of the faces of the structural film;

- at least one conductive routing track formed from a layer of conductive material on the other face of the structural film;

- at least two connection areas for each conductive routing track, delimited by through-cuts of the routing film and a fold adjacent to the connection area so that the connection area faces in the same direction as the corresponding conductive routing track, and in an opposite direction.

In addition, the connection areas of the flexible interconnection structure are electrically connected to the photovoltaic cells, following the predetermined interconnection pattern of the photovoltaic cells.

The front face of the photovoltaic module here refers to the face which is intended to be turned towards the light, while the rear face refers to the opposite face of the photovoltaic module.

The invention allows the production of a photovoltaic module even with strong integration constraints influencing the arrangement of the photovoltaic cells, while offering great freedom of electrical architecture for the cells. Complex electrical architectures, efficient in terms of shadow management, can thus be implemented even for integrations requiring an unfavorable physical arrangement of the cells, without requiring the implementation of non-standardizable solutions such as those requiring the use of half-cells, or complex physical arrangements of the cells.

The invention allows, for example, in the automotive field, the production of solar roofs respecting all the integration constraints specific to this type of application (need to distribute the cells over different zones, inhomogeneous surfaces, presence of spaces devoid of cells, etc.), without negative influence on the possibilities of cell interconnections, and therefore on the performance of the electrical architecture.

The invention provides a solution for interconnecting photovoltaic cells, as a single interconnection mode, or as a complement to another interconnection mode, at lower cost and with a level of reliability compatible with large-scale industrial applications.

The method according to the invention may include the following additional characteristics, alone or in combination:

- in the step of producing a routing film, the structural film is coated with a layer of conductive material, and the conductive routing track is formed by selectively removing portions of conductive material, without passing through the structural film, following the predetermined pattern of interconnection of the photovoltaic cells;

- the selective removal of portions of conductive material is carried out by etching the layer of conductive material;

- the selective removal of portions of conductive material, to form the conductive routing tracks, and the through-cuts of the routing film are carried out together by the same process;

- in the step of producing a routing film, the conductive routing track is directly deposited on the structural film, following the predetermined interconnection pattern of the photovoltaic cells; - the fold adjacent to the connection zone comprises a first substantially orthogonal fold between the conductive routing track and a through portion in the thickness of the structural film, and a second substantially orthogonal fold between this through portion and the connection zone;

- the through cuts are made along a contour surrounding the connection zone, this contour being interrupted by a folding section for carrying out said folding adjacent to the connection zone;

- during the step of forming at least two connection zones, the through cuts are made on end portions of the conductive routing track;

- the step of electrically connecting the connection areas of the flexible interconnection structure to the photovoltaic cells is carried out by a step of laminating all of the rear face layers;

- said back face layers comprise layers of encapsulating materials, the structural film and the layers of encapsulating materials being made of the same material;

- at least two of said connection zones are formed on two conductive routing tracks which are on two opposite faces of the structural film, these two connection zones being opposite each other;

- the same through cutout delimits the said connection zones opposite each other;

- said folding is adjacent to the two connection zones, and further comprises a bridging zone, beyond the connection zone, by which the two conductive routing tracks are electrically connected to each other;

- the fold adjacent to the connection zone comprises: a first substantially orthogonal fold between the conductive routing track and a through portion in the thickness of the structural film; a second substantially orthogonal fold between this through portion and the connection zone; a third substantially orthogonal fold between the connection zone and a transverse portion; a fourth fold substantially orthogonal between this transverse portion and the bridging zone.

- the bridging area comprises a bridging conductor connecting the connection area and one of the conductive routing tracks;

- the photovoltaic cells are connected by junction conductors, and at least one connection area is connected to a junction conductor.

PRESENTATION OF FIGURES

Other characteristics and advantages of the invention will emerge from the non-limiting description which follows, with reference to the appended drawings in which:

- figure 1 is a schematic top view of a solar roof for a motor vehicle;

- Figure 2 illustrates a network of photovoltaic cells suitable for implementation in the solar roof of Figure 1;

- figure 3 illustrates a step of the method according to the invention, in which a flexible interconnection structure is arranged on the network of photovoltaic cells of figure 2;

- figure 4 illustrates an example of a predetermined diagram for interconnecting photovoltaic cells which can be implemented with the method according to the invention;

- figure 5 illustrates a routing film suitable for producing the flexible interconnection structure implemented in the method according to the invention;

- figure 6, figure 7, figure 8 and figure 9 illustrate a first embodiment of the method according to the invention;

- figure 10, figure 11, figure 12 and figure 13 are additional illustrations of the first embodiment of the method according to the invention;

- figure 14, figure 15 and figure 16 illustrate a second embodiment of the method according to the invention; - Figure 17, Figure 18, Figure 19 and Figure 20 are additional illustrations of the second embodiment of the method according to the invention.

Elements similar and common to the various embodiments bear the same reference numbers in the figures.

DETAILED DESCRIPTION

Figure 1 illustrates an example of integration for a photovoltaic module produced according to the invention. Figure 1 is a schematic top view of a solar roof 1 intended for an automotive application. This solar roof 1 here represents an example of restrictive integration for a photovoltaic module.

In this illustrative example, the solar roof 1 has a window 2 in which a transparent wall or an opening roof is installed, which makes it a space necessarily devoid of photovoltaic cells.

A photovoltaic module designed like this solar roof 1 has a photovoltaic cell integration area which is located between the perimeter 3 of the solar roof 1 and the window 2. Areas of heterogeneous surface and restrictive passages (narrow areas, offsets, etc.) are present on this photovoltaic cell integration area. The surface of the solar roof 1 is also not necessarily flat over its entire extent.

Figure 2 is an example of arrangement of a photovoltaic cell array 4, in the area of the solar roof 1 which is available, according to the illustrated example.

According to the invention, the arrangement of the cells 4 within the available area in the photovoltaic module, in view of the integration constraints relating to this example of a solar roof, can be completely decoupled from the cell interconnection issues. The cells 4 can thus be physically arranged in the most efficient manner, essentially taking into account the geometric positioning constraints.

Figure 2 illustrates a simplified example in which cells 4 are arranged in the available area, all around window 2. In the illustrated example, the cells 4 are first interconnected in a conventional manner, each cell 4 being connected to the neighboring cell by any known means, such as glued or soldered conductive strips running along the rear face or the front face of the photovoltaic module.

In the example shown, the photovoltaic module uses two strings of 4 cells, connected in parallel. In each string, the 4 cells are in series.

According to this example given for illustration purposes, the photovoltaic module comprises a first connection conductor 5, which forms a first polarity of the module, and which connects to two adjacent cells 4A and 4B.

The first chain of cells includes cell 4A then all adjacent cells up to cell 4D, connected closely together using junction conductors 6. The second chain of cells includes cell 4B then all adjacent cells up to cell 4C, connected closely together using junction conductors 6.

The 4D and 4C cells are both connected to a second connection conductor 7 which forms the other polarity of the photovoltaic module.

The method for producing a photovoltaic module of this example implements the encapsulation of the cell network 4 by operations of placing front face layers and back face layers.

The front-face layering operations consist of installing various encapsulating materials, as well as a tempered glass that will form the front face of the module. The front-face layering operations are carried out in a known manner and will not be described in further detail here.

According to the invention, the placement of rear face layers comprises a step of placing a flexible interconnection structure on the rear face of the photovoltaic cells 4. The expression “on the rear face of the photovoltaic cells” encompasses both the placement of the flexible interconnection structure directly against the rear face of the cells 4, and the placement of the flexible interconnection structure with one or more layers intermediate between the cells 4 and the flexible interconnection structure, for example an electrically insulating layer.

Figure 3 illustrates the installation of this flexible interconnection structure 8 directly on the rear face of the cells 4.

The flexible interconnection structure 8 has a contour adapted to cover a predetermined area, so as to cover a predetermined interconnection pattern of the photovoltaic cells 4. The flexible interconnection structure 8 can have any type of contour depending on the application. The flexible interconnection structure 8 can cover the entire surface of the solar roof 1, with a contour corresponding for example to the perimeter 3 of the solar roof 1. The flexible interconnection structure can also, as in the example illustrated, cover only a portion of the surface occupied by the cell skeleton 4, if the predetermined interconnection pattern only concerns a part of the cells 4. The flexible interconnection structure can also cover a larger area than the area occupied by all of the cells 4, and can therefore, for example, comprise connection conductors running around the cell skeleton 4.

The flexible interconnection structure 8 comprises conductive routing tracks 9 making it possible to complete the interconnection of the network of photovoltaic cells 4. The flexible interconnection structure 8 is suitable, for example, for forming pairs of cells 4 placed at the same potential, regardless of the distance separating these cells 4. Independently of the physical integration constraints, any electrical architecture can thus be implemented for the photovoltaic module, and in particular architectures with high resilience in the face of partial shading problems.

Figure 4 is an example of a high-performance electrical architecture that is difficult to implement in a module with high integration constraints, and which can be easily implemented using the method according to the invention. The example of Figure 4 is independent of the examples illustrated in the other figures and illustrates a type of electrical architecture that can be implemented using the invention. In the architecture illustrated in Figure 4, six chains 10 comprising cells 4 implemented in series, are connected in parallel by junction conductors 6. At the same time, conductive routing tracks 9 allow isopotential connections.

In the schematic view of Figure 3, another example of a predetermined interconnection scheme is illustrated in more detail, with its isopotential connections of cells 4. In Figure 3, each end of the conductive routing track 9 is electrically connected to the cell 4 opposite it. Each conductive routing track 9 runs from one of its ends to the other of its ends, being electrically insulated from the cells 4, apart from the two cells that it connects. Each conductive routing track 9 thus makes it possible to put two cells 4, even distant ones, at the same potential.

The installation of the flexible interconnection structure 8 on the rear face of the cells 4 is followed by a step of electrical connection of each end of the conductive routing track 9 to the corresponding cell 4, following the predetermined interconnection diagram.

This step is followed by other standard steps relating to the operations of placing back-face layers. These include, for example, the placement of electrically insulating encapsulants, a back-face structural plate, etc. These other operations of placing back-face layers are standard and will not be described in further detail here.

Figures 5 to 20 illustrate process steps for producing the flexible interconnect structure 8.

According to a first embodiment relating to figures 5 to 13, the flexible interconnection structure 8 comprises a single layer of conductive routing tracks 9.

Figure 5 illustrates a first step in producing this flexible single-layer interconnection structure 8. This first step consists of associating a structural film 11 with a conductive layer 12.

The structural film 11 is formed from a sheet of electrically insulating material. In a particularly advantageous embodiment, the structural film 11 is made from a material conventionally used as an encapsulant in photovoltaic technologies, such as EVA, POE, or even kapton (registered trademark), etc.

The conductive layer 12 can advantageously be produced by metallization of the structural film 11, or by any other means such as lamination, bonding, etc.

The conductive layer 12 is intended to form the conductive routing tracks 9, independently of the structural film 11. According to the illustrative example of FIG. 5, the structural film 11 is first metallized over its entire surface, then etching operations make it possible to form the conductive routing tracks 9.

Figure 6 illustrates a step subsequent to the step of Figure 5, leading to the production of a routing film comprising the structural film 11 and one or more conductive routing tracks 9. In this step, one of the conductive routing tracks 9 is delimited by selective removal of the metallization, sparing the structural film 11, for example by etching (chemical, laser, etc.). In Figures 6 to 8, hatchings of different orientation illustrate the surfaces on which the metallization is present, and the surfaces on which it has been removed, revealing the structural film 11 located underneath.

In this simplified example for illustrative purposes, the etching delimits a conductive routing track 9 by removing a contour of the conductive layer 12. The structural film 11 retains its integrity.

The conductive routing tracks 9 can also be produced directly by selective metallization of the structural film 11.

Figure 7 illustrates the subsequent operation: a through cut 15 is made along a contour delimiting a connection zone 14 on a portion of the conductive layer 12. This through cut can be made by through etching of the structural film 11.

The through-cut 15 can be made after the etching delimiting a conductive routing track 9. Alternatively, the etching delimiting the conductive routing track 9 and the through-cut 15 can advantageously be made together by the same method. For example, the etching delimiting the conductive routing track 9 and the through-cut 15 can be made by the same laser engraving process, by adapting the laser power, and/or by making several passes of the laser.

The through-cut 15 thus delimits a connection zone on a portion of the conductive routing track 9. This portion of the conductive routing track 9 can be located at any point at which an electrical connection is desired, in accordance with the predetermined interconnection diagram. In the present example, the portion of the conductive routing track 9 on which the through-cut 15 is made, delimiting the connection zone 14, is an end portion.

To achieve the interconnection of the cells 4 using the flexible interconnection structure 8, at least one conductive routing track 9 is necessary with, on two of its portions (for example at each of its ends), a connection zone 14 delimited by the corresponding through-cut 15.

Figures 6 to 9 are figures, simplified for educational purposes, representing a single conductive routing track 9 with a single connection area 14 at one of its ends. In practice, the flexible interconnection structure 8 may comprise a large number of conductive routing tracks 9 produced in the same way, each of which may comprise several connection areas 14.

Figure 8 illustrates the next step in which a bend adjacent to the connection area 14 is made. Figure 9 is a sectional view of Figure 8 and illustrates the result of the bending.

The through-cut 15 is made along a contour surrounding the connection area 14, this contour being interrupted by a folding section for carrying out the folding adjacent to the connection area 14, this folding section being illustrated in dotted lines in Figure 7. The folding is carried out so that the connection area 14 is turned in the same direction D as the conductive routing track 9, but in an opposite direction. This means that the normal to the connection area 14 is oriented substantially in the same direction as the normal to the plane in which the conductive routing track 9 extends, and that the surface of the connection area 14, after carrying out the folding, is turned in a first direction 17 (downwards in the figure) while the surface of the conductive routing track 9 is facing in an opposite direction 16 (upwards in the figure).

More precisely, the fold adjacent to the connection zone comprises: - a first fold 23A substantially orthogonal (i.e. a fold approximately at a right angle), between the conductive routing track and a through portion 24 in the thickness of the structural film 11;

- and a second fold 23B substantially orthogonal (i.e. a fold approximately at a right angle) between this through portion 24 and the connection zone 14.

The steps described allow the production of a flexible interconnection structure 8 with conductive routing tracks 9 provided with connection areas 14 for each of the cells 4 to be interconnected according to the predetermined interconnection scheme.

The flexible interconnection structure 8 is placed on the cells 4 so that each connection area 14 comes against a corresponding connection area on the cell 4. Each connection area 14 of the flexible interconnection structure 8 is then electrically connected to the corresponding connection area on the cell 4, by any known means such as soldering, gluing, or even pressure contact.

Each cell 4 therefore has for this purpose a complementary connection zone, on its rear face or a junction conductor 6, against which the connection zone 14 of the flexible interconnection structure 8 is arranged, by virtue of the predetermined interconnection diagram. After this installation and this electrical connection of the flexible interconnection structure 8, the other conventional operations of installation of rear face layers can then be implemented.

Figures 10 to 13 are another illustration of this first embodiment in which the flexible interconnection structure 8 comprises a single layer of conductive routing tracks 9.

Figure 10 is a view of the rear face of three cells 4 connected in series. Figure 11 illustrates the next step of the method according to the invention, in which a flexible interconnection structure 8 is placed on the rear face of the cells 4.

The flexible interconnection structure 8 of this example also illustrates the possibility of directly depositing the conductive routing tracks 9 on the structural film 11, during the production of the routing film (rather than etching conductive tracks from a metallized surface).

The flexible interconnection structure 8 comprises conductive routing tracks 9 provided with different connection zones 14, as well as the through-cutouts 15 mentioned above, and the corresponding folds.

Figure 12 is a sectional view along section XII-XII of Figure 11 illustrating the composition of the module in thicknesses, with the front face layers 21, the cells 4, and the rear face layers which include the flexible interconnection structure 8. The conductive routing tracks 9 appear above the structural film 11 (in Figure 12) and thus route, in accordance with the predetermined interconnection diagram, while being electrically insulated from the cells 4 by the structural film 11.

Figure 13 is a view along section XIII-XIII of figure 11 and illustrates an interconnection of two of the cells 4 using a conductive routing track 9 and its two connection zones 14.

In Figure 13, the conductive routing track 9 is facing upwards (i.e. away from the rear face of the cells 4), while the two connection areas 14 are facing downwards, i.e. facing the rear face of the cells 4.

According to the predetermined interconnection diagram of this simplified example, the flexible interconnection structure 8 allows contact to be reestablished at two points where the junction conductors 6 are connected: points 18A and 18B. The two points 18A, 18B are thus brought to the same electrical potential thanks to the flexible interconnection structure 8. Figures 14 to 20 illustrate a second embodiment of the method according to the invention in which the flexible interconnection structure 8 comprises a double layer of conductive routing tracks 9.

Figure 14 is a sectional view similar to Figure 9, for this second embodiment.

According to this second embodiment, the flexible interconnection structure 8 is produced from a structural film 11 comprising a conductive layer on each of its faces. As for the first embodiment, the double conductive layer can be produced either by metallization of the entire two faces of the structural film 11 then etching the tracks, or by direct deposition of the conductive routing tracks 9 on each of the faces of the structural film 11.

The flexible interconnection structure 8 thus comprises conductive routing tracks 9A on one of its faces and conductive routing tracks 9B on the other of its faces.

The conductive routing tracks 9A and 9B each run independently on its respective face of the structural film 11, thus increasing the possibilities of interconnection trajectories, with possibilities of crossing tracks within the flexible interconnection structure 8. This second embodiment thus makes it possible to implement more complex predetermined interconnection schemes, by exploiting the two faces of the structural film 11.

Figure 14 illustrates a variant of the second embodiment, which is particularly advantageous. According to this variant, conductive routing tracks 9A, 9B each located on one face of the structural film 11 are both set to the same potential and connected to the connection zone 14 by means of a double fold so that these conductive routing tracks 9A, 9B come into contact at a bridging zone 19.

More specifically, the folding adjacent to the connection zone 14 comprises:

- a first fold 23A substantially orthogonal between the conductive routing track 9 and a through portion 24 in the thickness of the structural film 11;

- a second fold 23B substantially orthogonal between this through portion 24 and the connection zone 14; - a third fold 23C substantially orthogonal between the connection zone 14 and a transverse portion 25;

- a fourth substantially orthogonal fold between this transverse portion 25 and the bridging zone 19.

Thus, according to this variant of the second embodiment, the connection zone 14 (electrically connected to a cell 4) is the starting point of two conductive routing tracks 9A, 9B, which are therefore connected to the same point on the cell 4.

These two conductive routing tracks 9 can both be connected, moreover, by their other end, to another single cell 4, by another double fold identical to that described, located at the other end of the conductive routing tracks 9A, 9B. In other words, the two conductive routing tracks 9A, 9B can interconnect two cells by a parallel or different path. This makes it possible, for example, to double the cross-section of the conductor for certain interconnections between cells 4.

These two conductive routing tracks 9 can also route differently and connect, by their other end, to two different cells 4. A double fold such as that illustrated in figure 14 allows in this case two conductive routing tracks 9A, 9B to be connected to the same cell 4 by one of their ends, and to two different cells 4 by their other respective end.

Figure 15 illustrates another variant of this second embodiment, in which a simple bend and a bridging conductor 20 electrically connect the conductive routing tracks 9A and 9B. Any electrical interconnection technology can be envisaged for the bridging conductor 20 (soldering, welding, gluing, etc.).

According to these variants, at least two of the connection zones 14 are formed on two conductive routing tracks 9 which are on two opposite faces of the structural film 11, these two connection zones 14 being opposite each other. The same through cutout 15 delimits the two connection zones 14 opposite each other.

Figure 16 illustrates another variant of this second embodiment, particularly advantageous, in which, after the structure has been put in place flexible interconnection 8 and the installation of the other rear face layers in a conventional manner, the assembly is laminated so that this laminating operation results in:

- the electrical connection of the connection zones 14 of the flexible interconnection structure 8 to the corresponding cells 4;

- the leveling (flattening) of the flexible interconnection structure 8, by compression at the connection zones 14.

Advantageously, the leveling (flattening) of the flexible interconnection structure 8 will be facilitated by a thermal input making it possible to soften the structural film 11.

The flexible interconnection structure 8 thus obtained then has a single thickness, with connection operations which are carried out jointly with the rolling operations planned for the other rear face layers, thus reducing the number of steps required for the process. All of the rear face layers are thus arranged and electrically connected in a single rolling operation.

Preferably, according to this variant, the structural film 11 is made of the same material as the other encapsulant layers implemented in the other rear face layers. The lamination thus results in a homogeneous behavior of the different encapsulant layers, both for the structural film 11 of the flexible interconnection structure 8 and for the other layers, notably promoting the quality of the connections.

This variant with homogeneous rolling operation can also be applied to the first embodiment.

Figures 17 to 20 are another illustration of this second embodiment in which the flexible interconnection structure 8 comprises a double layer of conductive routing tracks 9A, 9B.

Figure 17 is a view of the rear face of three cells 4 connected in series. Figure 18 illustrates the next step of the method according to the invention, in which a flexible interconnection structure 8 is placed on the rear face of the cells 4. The flexible interconnection structure 8 comprises conductive routing tracks 9A, 9B provided with different connection zones 14, as well as the through-cutouts 15 mentioned previously, and the corresponding folds.

Figure 19 is a sectional view along section XIX-XIX of Figure 18. The conductive routing tracks 9A, 9B appear above and below the structural film 11 (in Figure 19) and thus run, in accordance with the predetermined interconnection pattern, while being electrically insulated from each other by the structural film 11.

Figure 20 is a view along section XX-XX of Figure 18 and illustrates an interconnection of two of the cells 4 by means of a conductive routing track 9A, located on the upper face of the structural film 11, and its two connection areas 14. Another conductive routing track 9B, located below the structural film 11, runs independently to connect other cells 4. In Figure 20, the upper conductive routing track 9A is facing upwards (i.e. opposite the rear face of the cells 4), while its two connection areas 14 are facing downwards, i.e. facing the rear face of the cells 4.

In the simplified example of Figures 18 to 20, the contact area 14 of the upper conductive routing track 9A is connected to the cells 4 via tracks 9C which extend against the rear face of the cells 4 and which are each electrically connected at several points on the rear face of a cell 4.

Furthermore, the conductive routing track 9B connects different connection points of a cell to an upper connection zone 22 adapted to be connected to any other interconnection device.

The examples described are simplified examples reflecting the interconnection possibilities permitted by the conductive routing tracks 9 and their connection zones 14, it being understood that any other predetermined interconnection scheme is possible.

Alternative embodiments may be envisaged. In particular, the connection zones may be located at any point on a conductive routing track 9: at the end of a routing track 9, as in the examples described, but also at any other more central point. Furthermore, a flexible interconnection structure 8 can be provided with several thicknesses, and would then comprise several structural films 11 provided with conductive routing tracks 9.

The flexible interconnection structure 8 can be implemented regardless of the technology of the cells 4 with respect to their connection mode, both with front-face contact cells and rear-face contact cells. The connections between the cells 4 and the connection areas 14 can be made both on the junction conductors 6 and directly on the rear-face contact cells.

The flexible interconnection structure(s) 8 may be provided in one or more parts. They may act as a complement to another interconnection mode, as in the examples described where the flexible interconnection structure comes in addition to the connections made by the junction conductors 6. They may also act as the sole interconnection mode, ensuring all the interconnections required in the chosen electrical architecture, up to the external connections of the module.

Claims

1. Method for producing a photovoltaic module, implementing an encapsulation of a network of photovoltaic cells (4) by operations of placing front face layers and rear face layers, this method being characterized in that the operations of placing rear face layers comprise the production of a flexible interconnection structure (8) according to the following steps: - producing a routing film comprising: a structural film (11) which is electrically insulating and has a predetermined area covering a predetermined interconnection pattern of the photovoltaic cells; at least one conductive routing track (9A) formed of a layer of conductive material on one of the faces of the structural film (11); and at least one conductive routing track (9B) formed of a layer of conductive material on the other face of the structural film (11); - forming at least two connection zones (14) for each conductive routing track (9A, 9B), by making through-cuts (15) of the routing film, each through-cut (15) delimiting a connection zone (14) on a portion of a conductive routing track (9A, 9B); - for each connection area (14), carry out a fold adjacent to the connection area (14) so that the connection area (14) is turned in the same direction as the corresponding conductive routing track (9), and in an opposite direction; and in that the operations of placing rear face layers further comprise the following steps: - placing said flexible interconnection structure (8) on the rear face of the photovoltaic cells (4); - electrically connecting the connection areas (14) of the flexible interconnection structure (8) to the photovoltaic cells (4), following the predetermined interconnection pattern of the photovoltaic cells. 2. Method according to claim 1, characterized in that, in the step of producing a routing film, the structural film (11) is coated with a layer of conductive material (12), and the conductive routing track (9) is formed by shrinkage. selectively portions of conductive material, without crossing the structural film (11), following the predetermined interconnection pattern of the photovoltaic cells. 3. Method according to claim 2, characterized in that the selective removal of portions of conductive material is carried out by etching the layer of conductive material (12). 4. Method according to one of claims 2 or 3, characterized in that the selective removal of portions of conductive material, to form the conductive routing tracks (9), and the through-cuts (15) of the routing film are carried out together by the same method. 5. Method according to claim 1, characterized in that, in the step of producing a routing film, the conductive routing track (9) is directly deposited on the structural film (11), following the predetermined interconnection pattern of the photovoltaic cells. 6. Method according to one of the preceding claims, characterized in that the folding adjacent to the connection zone (14) comprises a first fold (23A) substantially orthogonal between the conductive routing track (9) and a through portion (24) in the thickness of the structural film (11), and a second fold (23B) substantially orthogonal between this through portion (24) and the connection zone (14). 7. Method according to one of the preceding claims, characterized in that the through cuts (15) are made along a contour surrounding the connection zone (14), this contour being interrupted by a folding section for carrying out said folding adjacent to the connection zone (14). 8. Method according to one of the preceding claims, characterized in that, during the step of forming at least two connection zones (14), the through cutouts (15) are made on end portions of the conductive routing track (9). 9. Method according to one of the preceding claims, characterized in that the step of electrically connecting the connection zones (14) of the flexible interconnection structure (8) to the photovoltaic cells (4), is carried out by a step of laminating all of the rear face layers. 10. Method according to one of the preceding claims, characterized in that said rear face layers comprise layers of encapsulating materials, and in that the structural film (11) and the layers of encapsulating materials are made of the same material. 11. Method according to one of the preceding claims, characterized in that at least two of said connection zones (14) are formed on two conductive routing tracks (9) which are on two opposite faces of the structural film (11), these two connection zones (14) being opposite each other. 12. Method according to claim 11, characterized in that the same through cutout (15) delimits said connection zones (14) opposite each other. 13. Method according to one of the preceding claims, characterized in that said folding is adjacent to the two connection zones (14), and further comprises a bridging zone (19), beyond the connection zone (14), by which the two conductive routing tracks (9A, 9B) are electrically connected to each other. 14. Method according to claim 13, characterized in that the folding adjacent to the connection zone (14) comprises: - a first fold (23A) substantially orthogonal between the conductive routing track (9) and a through portion (24) in the thickness of the structural film (11); - a second fold (23B) substantially orthogonal between this through portion (24) and the connection zone (14); - a third fold (23C) substantially orthogonal between the connection zone (14) and a transverse portion (25); - a fourth substantially orthogonal fold between this transverse portion (25) and the bridging zone (19). 15. Method according to claim 13, characterized in that the bridging zone (19) comprises a bridging conductor (20) connecting the connection zone (14) and one of the conductive routing tracks (9). 16. Method according to one of the preceding claims, characterized in that the photovoltaic cells (4) are connected by junction conductors (6), and in that at least one connection zone (14) is connected to a junction conductor (6). 17. Photovoltaic module comprising an array of photovoltaic cells (4) encapsulated between front face layers and rear face layers, characterized in that it comprises a flexible interconnection structure (8) arranged on the rear face of the photovoltaic cells (4), and comprising: - a structural film (11) which is electrically insulating and has a predetermined area covering a predetermined pattern of interconnection of the photovoltaic cells; - at least one conductive routing track (9A) formed from a layer of conductive material on one of the faces of the structural film (11); - at least one conductive routing track (9B) formed from a layer of conductive material on the other face of the structural film (11); - at least two connection zones (14) for each conductive routing track (9A, 9B), delimited by through-cuts (15) of the routing film and a fold adjacent to the connection zone (14) so that the connection zone (14) is turned in the same direction as the corresponding conductive routing track (9A, 9B), and in an opposite direction; the connection zones (14) of the flexible interconnection structure (8) being electrically connected to the photovoltaic cells (4), according to the predetermined interconnection pattern of the photovoltaic cells.