FR3073981A1 - SEMI-TRANSPARENT MULTI-CELL PHOTOVOLTAIC MODULE SUBJECTED TO RECURRENT PERIPHERAL SHADING - Google Patents

Abstract

The invention relates to a semi-transparent photovoltaic module consisting of a plurality of photovoltaic cells electrically connected in series, said cells being composed of: - active areas (2) photovoltaic contained in crowns called active crowns, said photovoltaic active areas of the same active ring being separated by isolation zones (4); - vacant space (3) forming areas of transparency in transparent crowns; two adjacent crowns being separated by a transparent crown (3) and two active adjacent photovoltaic active area (2) belonging to the same cell being connected by at least one conductive interconnection bridge (8). Said module is characterized in that the adjacent isolation zones (4) are not facing each other.

Description

SEMI-TRANSPARENT MULTI-CELL PHOTOVOLTAIC MODULE SUBJECT TO RECURRENT PERIPHERAL SHADING

The present invention relates to the field of semi-transparent thin-film photovoltaic modules having a multi-cell architecture and subjected to peripheral shading effects intrinsic to the device with which it is associated. These modules are intended to produce electrical energy and / or to function as photovoltaic sensors or transducers.

STATE OF THE ART

A thin-film photovoltaic cell is composed of at least one substrate, a first transparent electrode, a second generally metallic electrode and a layer of absorber. By thin layers is meant photovoltaic layers of any kind (organic, inorganic), the thickness of the absorber does not exceed ten micrometers.

A thin-film photovoltaic module is made up of a multitude of thin-film photovoltaic cells. Generally, it is made up of several photovoltaic cells connected in series in order to increase the electrical voltage across the module. There are known methods for placing photovoltaic cells in series by successive stages of isolation and interconnection of the different layers which make up the thin-film photovoltaic module as described in document EP0500451-B1.

A thin-film photovoltaic cell semi-transparent to visible light may include a plurality of opaque active photovoltaic zones separated by transparency zones. The photovoltaic zones can be of any shape and of dimensions such that the human eye does not distinguish them. To do this, the width of the photovoltaic zones is preferably less than 200 micrometers. In a known embodiment, the active photovoltaic zones and the transparency zones are organized into networks of elementary, linear, circular or polygonal geometric structures. The transparency of the photovoltaic cell is a function of the surface fraction occupied by the opaque active photovoltaic zones. Patent WO2014 / 188092-A1 presents an embodiment of a semi-transparent photovoltaic mono-cell in thin layers. In an advantageous embodiment, the transparency zones are arranged in the transparent electrode in addition to the metal electrode and the absorber in order to increase the light transmission at the level of the transparency zones, since by reducing the number of interfaces, the optical phenomena of reflections at the interfaces are minimized.

It is known to those skilled in the art that the electric power generated by a photovoltaic module can be greatly reduced compared to optimal conditions for energy production, in particular during the partial or total shading of all or part of the photovoltaic cells composing a photovoltaic module. . Semi-transparent photovoltaic modules are subject to the same type of stress. In particular, shading a part of a semi-transparent photovoltaic module whose semi-transparent cells are all connected in series has a drastic impact on the power-voltage curve, even if a very small part of the module or of the cell is shaded. Indeed, in a serial architecture, the current is the same in all cells. For example, if a single cell is shaded and it experiences a 25% current loss, then the current generated by the module also suffers the same loss.

The standardization of the integration of photovoltaic modules generates new problems. In the case of the integration of semi-transparent modules in watches, it is advantageous to use the same module design whatever the configuration of the watch flange (in order to reduce the production costs of said modules). The flange which forms the junction between the dial and the watch glass, depending on its design, may be more or less wide, more or less transparent, which generates different shading effects according to said design. In the remainder of this document, the term recurring enhancement means any device which causes a permanent shading effect on the semi-transparent photovoltaic module integrated in a system such as a watch.

In order to minimize the impact of the shading effects of the flange on a semi-transparent photovoltaic module with serial architecture, it is necessary to distribute this shading evenly, otherwise one or more cells would be more shaded and would drastically affect the module performance. The patent US6372977-B1 proposes a particular embodiment which solves this problem. The architecture of one of the semi-transparent photovoltaic modules proposed is made up of 4 cells connected in series with equivalent surfaces. Photovoltaic zones are arcs of circles connected by interconnection bridges. However, in this type of architecture, the insulation lines are straight lines which are visible to the eye because they create a disturbance in the circular symmetry of the architecture of the photovoltaic zones.

The object of the invention is to make the cell separations more commonly called lines of isolation invisible to the naked eye, even for modules with circular geometry, particularly suitable in particular for the manufacture of solar watches.

PURPOSE OF THE INVENTION

The object of the invention is to propose a semitransparent photovoltaic module composed of a multitude of cells in semitransparent thin layers connected in series and having an improvement in the visual quality of the cells when they are subjected to recurrent or even permanent shading effects. .

OBJECTS OF THE INVENTION

The subject of the invention is a new semi-transparent photovoltaic module composed of a multitude of cells in semi-transparent thin layers connected in series and subjected to recurring or even permanent shading effects, including the active zones, the transparency zones. , and the interconnection bridges between active zones are placed so that the isolation lines and the interconnection bridges are less visible, or even invisible to the naked eye for an observer placed a few centimeters from the photovoltaic surface .

The invention also relates to a watch provided with such a photovoltaic module, and a glazing provided with such a photovoltaic module.

The invention also relates to a method of designing such a photovoltaic module.

In the rest of the document, the term “crown” refers to a continuous zone of defined thickness, constant or not, forming a closed line around a central point. By way of example, a ring is a crown with circular symmetry.

A crown is characterized by:

- its inner line defined as the smallest closed line composing it;

- its outer line defined as the largest closed line composing it;

- its central point;

- its width defined at a point as the smallest distance between the inner line and the outer line.

A ring is therefore defined by its central point which is the center C, its inner line corresponding to the minimum radius R _m in and its outer line corresponding to the maximum radius R _ma x · In the case of a ring, the width is constant, it is defined as the smallest distance separating the minimum radius Rmin from the maximum radius R _ma x of the ring.

A crown is formed from one or more materials. According to the invention, a crown consists mainly of active materials forming active zones, advantageously active photovoltaic zones. Spaces which are not active areas will be designated by the term vacant space. These vacant spaces have the particularity of not being electrically conductive.

An area of insulation is defined as a space forming an electrical discontinuity within the active surfaces belonging to the same ring. This isolation zone electrically isolates the adjacent active zones.

A crown portion defines a continuous portion of said crown. This crown arc is defined for example by its center, its interior line, its exterior line, its starting angle dd and its stopping angle aa relative to a reference position. For example, a ring arc is therefore defined by its center, its radius Rmin, its radius R _ma x, its start angle dd and its stop angle Âa.

In the rest of the document, we will consider semi-transparent photovoltaic modules. The vacant spaces correspond to the transparency zones.

According to the invention, a semi-transparent photovoltaic module consists of a plurality of photovoltaic cells electrically connected in series. Said cells are composed:

- active photovoltaic areas contained in rings called active rings, said active photovoltaic areas of the same active ring being separated by isolation areas;

- vacant spaces forming areas of transparency according to transparent crowns;

two adjacent active rings being separated by a transparent ring and two active photovoltaic areas of adjacent active rings belonging to the same cell being connected by at least one conductive interconnection bridge.

Said cells are characterized in that the portions of adjacent isolation zones are not facing each other.

Advantageously, the conductive interconnection bridges are also not facing each other.

In order to increase transparency, the portions of insulation zones are transparent.

Preferably, the active crowns are all of the same geometrical nature.

For example, for applications using a semitransparent photovoltaic module integrated in electronic devices with circular geometry such as watches, it is recommended that the active crowns and transparent crowns be concentric rings. In order to solve the problem of the heightening of watches generating partial shading of the photovoltaic module, it is desirable that the active crowns are spaced radially by a pitch P _a constant and that they have a constant width.

Advantageously, the ring is only composed of active photovoltaic zones.

Advantageously, the active photovoltaic zones are the same width as the active rings and have a constant width CD. So that these active areas are imperceptible to the eye, the width of the active areas will ideally be between 10 nm and 50 μm. Advantageously, the active photovoltaic zones are included in the active rings, but the active ring can be composed of active zones and non-active zones.

In order to minimize the addition of material and to make the interconnection bridges invisible, it is desirable that the length of the interconnection bridges is equal to P _a - CD. In order not to create visual disturbance between the network of concentric rings and the network of interconnection bridges, it is necessary that the width of the concentric rings and the width of the interconnection bridges are of the same order of magnitude. Advantageously, said widths are equal. Furthermore, in order not to create an ordered network of interconnection bridges which would be detectable with the naked eye, the interconnection bridges are distributed randomly between two active photovoltaic zones of adjacent active rings belonging to the same cell.

Advantageously, the total area of all the interconnection bridges does not exceed 10% of the total area of all the active areas of the photovoltaic module.

In order to increase the efficiency of the photovoltaic module, the interconnection bridges are formed of thin layers identical to the active photovoltaic zones so that said bridges are not only conductive but also convert the light energy received.

In order to realize the architecture of such a photovoltaic module, the process for designing the semi-transparent photovoltaic module comprises the following steps:

1. Create a working file or image;

2. Choose the initial parameters;

3. Calculate the length of the crown arcs;

4. Calculate the departure angles;

5. Calculate stopping angles;

6. Draw the crown arcs from the pre-calculated parameters;

7. Determine the placement terminals of the interconnection bridges;

8. Choose the placement of the interconnection bridges;

9. Draw the interconnection bridges.

- A crown arc of index (i, R _k ) is defined by its mean radius (R | <), its width (CD), its starting angle (Âdi, _{R k} ) and its arc length (Larc_k ).

- The angle didi, _Rk is an angle measured in radians whose value is chosen random between 0 and 2 n / N.

For any integer k ranging from 1 to the total number (NB) of crowns, the condition (Âdi, _R _ _k Φ Âdi, _Rk -i) and (Âdi, _{R k} Φ Âd _{t / R} _ _{k +} i) for k> 1 is verified, for any integer k going from 1 to NB and all integer i going from 1 to N, the stopping angle of the drawing of the arc of a circle of index (i, Ri <) is calculated according to: Âai , _R _ _k = Âd _{i +} i, _{R k} - ü _k where ü _k corresponds to the angle measured in radian associated with the inter-arc length and associated with the ring of average radius R _k . This angle is defined by the relation: ü _k = L _in ter_arc / Rk-

- the choice of terminals delimiting the placement of the interconnection bridges is defined according to the following sub-steps:

o Define the interval Ii by h = [Âdi, _{R k +} i, Âai, _R _ _{k +} i] o Find the two values among the Âdi, _Rk and Âaj, _{R k} for i varying from 1 to N which belong to the interval Ii, where  _min is the smaller of these two values and  _ma x is the larger.

If Amin and  _max have the same index, they are the two limits delimiting the placement of the interconnection bridges.

Otherwise, we search for the index i of the arc of radius R _k and the two limits of the maximum difference Âdiff such that Âdiff = Max ((Âmin - Âdi, _R _k + i), (Âai, _R _k ₊ i -  _max )). This index i therefore defines the crown arc of radius R _k which optimizes the maximum of interconnection bridges between the crown arc of radius Rk + i and of index 1 and the crown arc of radius R _k and of index i. The two limits of the difference, either  _m in and Âdi, _R _ _k + i or Âai, R_ _k + i and Âmax are the two limits delimiting the placement of the interconnection bridges.

Advantageously, the placement of the interconnection bridges is random within the terminals delimiting the placement of said interconnection bridges.

The photovoltaic module according to the invention, in particular in its circular geometry form, adapts perfectly in electronic devices such as watches without being drastically affected by their heightened energy.

This type of photovoltaic module according to the invention can also be integrated into any semi-transparent support such as for example a glazing.

DETAILED DESCRIPTION

The invention is now described in more detail using the description of Figures 1 to 4.

Figure IA is a diagram showing a flower-shaped crown. Figure IB is a diagram showing a ring-shaped crown.

Figure IC is a diagram representing a ring-shaped crown split into two arcs of crowns by two zones of insulation.

FIG. 2A is a diagram representing a semitransparent photovoltaic module intended to be integrated in a watch of circular geometry. The case of a watch having a recurring flange generating permanent shading at the periphery of the photovoltaic module is explained in FIG. 2B.

FIG. 3A is an example of a semi-transparent photovoltaic module composed of a single cell whose circular photovoltaic active zones are electrically connected to each other by interconnection bridges.

Figures 3B and 3C schematize a semi-transparent photovoltaic module based on the same architecture as Figure 3A to which we added isolation zones (placed in straight or curved lines) to form 4 cells whose active surfaces are equal.

Figures 4A, 4B are the same block diagram showing the 4 arcs of circles of the first and second radius of the structure according to the invention.

In all of the figures, two axes (X) and (Y) forming an orthonormal reference frame are shown in order to facilitate the geometric description of these.

Figure IA is a diagram showing a crown (1) in the shape of a flower. The crown is defined by:

- its inner line (11) defined as the smallest closed line composing it;

- its outer line (12) defined as the largest closed line composing it;

- its central point (13) which is the center of symmetry of the geometric figure, and which also materializes the origin of the orthonormal coordinate system (X; Y) ·

In this particular case, the crown does not have a constant width.

FIG. 1B is a diagram representing a ring-shaped crown (1) defined by:

- its inner line (11) corresponding to a circle of minimum radius R _m in;

- its outer line (12) corresponding to a circle of maximum radius R _ma x;

- Its central point (13) corresponding to the center of the circles of radii R _m in θί Rmax ·

Unlike the case of Figure IA, the crown has a constant width. The crown (1) is formed from one or more materials. According to the invention, all or part of a ring (1) consists of active materials forming active zones (2), advantageously active photovoltaic zones. When the crown is not exclusively constituted by the active zones (2), it has vacant spaces (3) which are electrically non-conductive zones which may or may not be transparent.

FIG. 1C is a diagram representing a ring-shaped crown split into two crown arcs (14) by two isolation zones (4). Isolation zone (4) defines a space forming an electrical discontinuity within the active zones belonging to the same ring. This isolation zone electrically isolates said active zones from the crown. In the case shown, the crown arcs (14) are ring arcs. A ring arc is characterized by its center (13), its circular arc of radius R _min (11), its circular arc of radius R _max (12), its starting angle (15) and its angle of stop (16). Its starting angle dd (15) is defined as the angle counted positively (according to the convention of trigonometry) going from the axis of (X) to the starting half-line (15A) which originates from the center ( 13) and which intercepts the first end (15B) of the crown arch (14). Its angle of arrival Âa (16) is defined as the angle counted positively going from the axis of (X) to the half-line of arrival (16A) which originates from the center (13) and which intercepts the second end of the arc (16B).

FIG. 2A is a diagram representing a semitransparent photovoltaic module (5) intended to be integrated in a watch of circular geometry. The front (6A) and rear (6B) contact buses are arranged at the end of the semi-transparent active areas. The case of a watch having a recurring flange generating permanent shading (7) on the periphery of the photovoltaic module is shown in FIG. 2B.

In order to simplify FIGS. 3A, 3B, 3C, the front and rear contact buses are not shown. Only the location (6) of these buses is materialized at the end of the modules. Those skilled in the art will know how to place them suitably according to the architecture of the modules.

FIG. 3A is an example of architecture known from the state of the art of a single photovoltaic cell with circular geometry and whose active photovoltaic zones (2), in the form of concentric rings, are electrically connected to each other by a plurality of interconnection bridges (8). The interconnection bridges (8) are conductive elements allowing the charges (electrons and holes) to flow between the active rings (2) to be collected at the level of the buses (6). When they are not transparent, the interconnection bridges (8) are preferably made of the same materials as those making up the rings (2) to generate current by photovoltaic effect.

The active photovoltaic zones (2) are separated by vacant spaces (3) which are zones of transparency also in the form of rings. These transparency zones are openings arranged at least in the non-transparent materials constituting the active zones (metal electrode and absorber) to allow maximum light to pass through. Advantageously, these openings are also arranged in the transparent electrode. In this example, the active photovoltaic zones (2) are of the same dimensions as the active rings (1) shown in FIG. 1B.

In this example, the width CD (acronym of the English term "critical dimension" or critical dimension) of the active photovoltaic zones (2) is defined as the difference between the radius R _ma x of the circle (12) and the radius R _m i _n of the circle (11). Advantageously, this width is constant within the same ring. Preferably, all the active photovoltaic zones (2) have the same width. The latter is advantageously between 10 nm and 50 pm, which allows the network of active crowns to be imperceptible by the human eye. We define the line (R12) equidistant from the interior (12) and exterior (11) lines. In the case of a ring, this line (R12) materializes the circle of mean radius R of the ring, such that R = (R _max + R _m in) / 2. The pitch P _a of the ring network is defined as the minimum distance between two mean radii R of adjacent rings. The pitch P _a of active crowns can be different from the pitch P _t of the transparent crowns, in particular when the width CD is not constant. In the case of FIG. 3A, P _a = P _t . The length L of the interconnection bridges (8) is defined as the length of the segment separating the circle of radius R _max from one ring from the circle of radius R _min from its largest adjacent ring. Advantageously, said length L is the minimum length which separates them, satisfying the following relationship: L = P _a CD. The interconnection bridges (8) have widths preferably equivalent to the width CD of the photovoltaic active zones (2) and are distributed randomly between two adjacent active rings. Advantageously, the distance d between two bridges connecting two adjacent active rings is between 200 and 1000 μm in order to optimize the electrical conductivity within the photovoltaic cell.

From this single cell, it is possible to manufacture photovoltaic modules composed of several cells connected in series in order to increase the voltage across the photovoltaic module. It is then necessary to create isolation zones within the architecture described in FIG. 3A.

FIG. 3B is an example of such a photovoltaic module architecture known in the state of the art. Insulation lines (41) have been added to the diagram in FIG. 3A to form 4 photovoltaic cells whose active surfaces are equal. In this example, the insulation lines (41) are straight lines which are perceptible to the eye because they create a disturbance in the circular symmetry of the architecture of the photovoltaic active areas. All photovoltaic active rings (2) are cut by isolation zones (4) into 4 arcs of active rings (14) with the same active surface, therefore of the same length. Thus, between two adjacent active rings (2), all the insulation zones (4) are facing one another in a radial direction to form the 4 clearly visible lines of insulation (41), which is problematic.

FIG. 3C is a diagram of a photovoltaic module architecture according to the invention, containing aligned insulation lines (42) making it possible to create 4 photovoltaic cells whose active surfaces are equal. Compared to FIG. 3B, the invention therefore consists in modifying the placement of the isolation zones (4) so that two isolation zones (4) belonging to two adjacent active rings (2) are never in look at each other. A possible example of isolation lines has been shown by the dotted path (42). In this type of architecture, the non-linear insulation lines (42) are no longer perceptible, while maintaining 4 photovoltaic cells connected in series.

Such an architecture can be obtained by the arrangement method explained below. Said method for arranging active photovoltaic zones and their interconnections is described for a semi-transparent module of 4 cells connected in series. In this process, the cells are formed by arcs of rings interconnected by bridges. Each cell is therefore a succession of arcs of rings whose mean radius R varies according to a constant pitch P _a . For a given radius, the 4 arcs of rings of the same average radius R have the same surface (equal arc lengths and constant CD width).

The steps of the algorithm for designing a possible structure of the photovoltaic module according to the invention are described below.

To simplify their reading, the architectures shown diagrammatically in FIGS. 4A and 4B are exactly the same. Only what is annotated there differs from one figure to another.

FIG. 4C shows a different arrangement of the crown arcs in comparison with FIGS. 4A and 4B.

Parameter definition:

- image resolution (DU);

- the mean radius (Ri <), k being the index of the radius, k = l corresponding to the smallest radius considered;

- the total number of rings (NB);

- the constant width (CD) of the rings;

- the total number of cells (N);

- the constant inter-arc length (Lmter-arc);

- the length of the arc of radius Ri <(La _rc _k);

- the length of the arc of radius R _k between cells (L _in ter-ceiLk);

- the number of cell i, such that the first cell has an index i = l;

- the starting angle (Âdj, R _k ) of the arc of index (i, Rk);

- the stopping angle (Âaj, _{R k} ) of the arc of index (i, R _k );

- the pitch of the network (P _a , _k ): P _a , k = Rk + i - R _k , k> 1 considered here as constant and of value (P _a );

- the minimum distance between two interconnection bridges (d).

By convention, the angles are measured according to the trigonometry convention.

Step 0: Creation of a working file or image.

Step 1: Choice of initial parameters:

- image resolution (DU);

- the smallest dimension of the photovoltaic active zones, corresponding to the width of the arcs of rings (CD);

- the number of cells (N);

- the number of rings (NB);

- the inter-arc length defined as the length of the insulating arcs (L _in terarc) 'i

- the average radius (Ri) of the active crown of index 1;

- the average radius (R _N b) of the active crown of index NB;

- the pitch of the network (P _a ) of the ring network;

- the minimum distance between two interconnection bridges (d).

Step 2: Calculation of the length of the arcs for any integer k going from 1 to NB.

An arc of index (i, Rk) is defined by its mean radius (R _k ), its width (CD), its starting angle (Âdj, _{R k} ), its arc length (L _arc _k) arc length is calculated according to the formula: L _ar c_k ⁼ Ljnter-cell_k Ljnter- _a rc ⁼ (2πΡι </ Ν) - Linter-arc In this particular case, the arcs of circle of the same mean radius have the same length.

By convention, in the rest of the document, for a given mean radius R, the index i = l is reserved for the ring arc whose starting angle dd has the smallest value. The index i = 2 is reserved for the ring arc which has the second smallest starting angle value. The process will be repeated to assign the following indices in the same manner. For example, within FIG. 4A are represented:

- the arc (141) of index (l, Ri) of the active crown of medium radius Ri;

- the arc (142) of index (2, R _X ) of the active crown of medium radius Ri;

- the arc (14Γ) of index (1, R ₂ ) of the active crown of medium radius R ₂ ;

- the arc (142 ') of index (2, R ₂ ) of the active crown of medium radius R ₂ .

In this particular example, the arc (141) of index (1, Ri) is opposite the arc (141 ^ of index (1, R ₂ ).

Step 3: Calculation of the starting angles dj, _{R k} for any integer k ranging from 1 to NB and all integer i ranging from 1 to N.

Âdi, R_k is an angle whose value is chosen random between 0 and 2π / Ν characterized in that (Âdi, _R _ _k * Âdi, _R _ _k -i) and (Âdi, _R _ _k * Âdi, _R _ _{k +} i) for k> 1. We call secondary arcs the arcs of rings from the starting angles dj + i, _{R k} such that i> l. The starting angles of the secondary arcs are calculated according to:

Âdj, _R _ _k = Âdj-i _{/ R} _ _k + (2π / Ν) * (ΐ-1) for i> 1.

In FIG. 4B is shown the starting angle didi, i (15 ′) of the arc (141) of index (1, Ri).

Step 4: Calculation of stopping angles Âaj, _{R k} for any integer k ranging from 1 to NB and all integer i ranging from 1 to N.

Let ü _{k be} the angle associated with the inter-arc length associated with the ring of average radius R _k . This angle is defined by the relation: ü _k = Linter_ ^ arc / Rk. The stopping angle of the drawing of the arc of index (i, Ri <) is calculated according to the formula: Âaj, _{R k} = Âd _{i +} i, _{R k} - ü _k .

An example of an inter-arc angle Π ₂ (9) of mean radius R ₂ is shown in FIG. 4A, while the stopping angle aiai, _R _i (16 ′) of the arc (141) ′ index (l, Ri) is shown in Figure 4B.

Step 5: Plots of the ring arcs for any integer k going from 1 to NB and all integer i going from 1 to N.

The plots of the ring arcs of index (i, R _k ) are carried out by considering the mean radius R | <as well as the width CD of the rings. The route begins, for example, from the starting angle Âdi, _{R k} and ends by considering the stopping angle Âa _izR _ _k . Those skilled in the art will be able to trace these ring arcs by other methods using the parameters described above (starting angle, stop angle, length of arcs, mean radius, maximum radius, minimum radius). All the tracks are therefore not described here.

Step 6: Determination of the placement terminals of the interconnection bridges.

To form a cell, it is necessary to connect step by step an arc of crown of average radius R _k to an arc of crown of average radius Ri < ₊ i, for k going from 1 to NB. In order to electrically optimize the cell, it is imperative to maximize the number of interconnection bridges. In order to achieve this condition, the choice of crown arcs to be connected must be optimized. For example, the crown arc of average radius Rk and of index 1 can be connected to the arc of a circle of radius Rk + i but of index 2. To seek this optimization, a solution consists in:

- Define the interval Ii by I _x = [Âdi, _Rk + i, Âai, _R _k + i]

- Search among the Âdi, _{R k} and Âai, _R _ _k (for i varying from 1 to N) all the values which belong to the interval Ii. We denote by _min the smallest of these values and by _ma x the largest.

O If Amin and Âmax have the same index i, they are the two limits delimiting the placement of the interconnection bridges.

o Otherwise, we search for the index i of the arc of radius Rk and the two limits of the maximum difference Âdiff such that Âdifr = max ((Â _m in - Âdi, _R _k + i), (Âai, _R _k + i - Âmax)) This index i therefore defines the circular arc of radius Rk which optimizes the maximum of interconnection bridges between the circular arc of radius Rk + i and of index 1, and the circular arc with radius R _k and index i. The two terminals of the difference (Â _m în and Âdi, _R _k + i) or (Âai, _R _k + i and Âmax) are the two terminals delimiting the placement of the interconnection bridges.

To illustrate this step, a first example is given below based on the diagrams of FIGS. 4A and 4B.

- The interval Ii is defined by the starting angles Âdi, _R 2 and stopping Âai, _R 2 (not shown) of the arc (141 ^, such that Ii = [Âdi, _{R 2} , Âai, _R _ ₂ ].

- One searches, among the starting and stopping angles of radii Ri, the values of the starting and stopping angles as they belong to the interval Ii.  _m in corresponds to the starting angle Âdi, _R _i (159 and  _ma x corresponds to the stopping angle Âai, _R _i (16 ⁷ ). Âmin and  _ma x belong to the same arc of circle index (l, Ri). They therefore correspond to the two terminals delimiting the placement area (81) of the interconnection bridges.

Alternatively, a second example is described from the diagram in Figure 4C. In this figure, only the values of interest are represented, to improve readability.

- The interval Ii is defined by the angles of departure Âdi, _R _ ₂ (not shown) and stop Âai, _{R 2} (16) of the arc (141) such that Ii = [Âdi, _R _ ₂ , Âax, _R _ ₂ ].

- One again searches, among the starting and stopping angles of radii Ri, the values of the starting and stopping angles as they belong to the interval Ιχ.  _min corresponds to the stopping angle Âai, _R i (not shown) and Âmax corresponds to the starting angle Âd _{2 / R} _x (15).  _m in belongs to the arc of index 1, R_1 and  _max belongs to the arc of index 2, R_1.  _m in and  _ma x do not therefore belong to the same arc.

- In this case, we seek the index i of the arc of radius such that Âdifr = max ((Â _min - Âdi, R_ ₂ ), (Âai, R_ ₂ - Âmax)) = (Âax, _R _ ₂ - Âd ₂ , _R _x). The index i is the index 2. The placement area (81) is delimited by the angles IAA, _{R 2} _ (16) and AD _2, R_i (15). In order to optimize the number and placement of the interconnection bridges, cell 1 will be made up of the arc (141) of index (2, Ri) and the arc (1429 of index (1, R ₂₎ We repeat this operation between all the ring arcs to find the locations of each batch of interconnect bridges.

Step 8: Placement of the interconnection bridges.

The interconnection bridges of width CD are placed between the terminals defined in step 7 so that the distance d between two interconnection bridges is at least equal to the pitch P _a . Advantageously, so that the density of bridges is not visible, the inter-bridge distance (d) is at least equal to ten times the value of the step P _a .

In particular, it is advantageous to place these bridges randomly. To do this, we randomly search for an angle Âa _L x between the two terminals defined in step 7, and we place the first interconnection bridge between the two arcs of circles defined by said terminals. We can repeat the step of finding a random angle from one of the bounds and the angle Aai_x previously calculated. If the angle sought verifies the condition of inter-bridge distance (d), the interconnection bridge is placed at this angle. The operation is repeated and it stops when it is no longer possible to place bridges.

Nomenclature used for the description of all the figures:

1 Crowned 11 Inner line of the crown 12 Outer line of the crown R12 Line equidistant from the inside and outside line 13 Central point 14 Crown arch 141, 14Γ, 141 Crown arch with index i = l 142, 142 ', 142 Crown arch with index i = 2 15, 15 ', 15 Departure angle Âd 15A Half starting line 15B First end of the crown arch 16, 16 ', 16 Angle of arrival Âd 16A Arrival half right 16B Second end of the crown arch 2 Active area 3 Vacant space 4 Isolation area 41 Linear insulation line 42 Non-linear insulation line 5 Semi-transparent module 6 Bus location 6A Front contact bus 6B Rear contact bus 7 Shading linked to a watch flange 8 Interconnection bridge 81 Interconnection bridge placement area 9 Inter-arc angle

EXAMPLE OF IMPLEMENTATION

The process which is the subject of the invention can be implemented by considering a photovoltaic module based on amorphous silicon deposited on a glass substrate. The electrodes consist of a transparent conductive oxide on the front side and of aluminum on the rear side. The stack of thin layers composing said photovoltaic module is protected by a transparent encapsulation material. Semi-transparency is achieved either by local and selective laser ablation of the material or by standard photolithography processes. Here are the initial parameters for the design:

- The resolution of the image is fixed at 1 nm;

- The photovoltaic width of the arcs of circles is 20 pm;

- The number of cells is 4;

- The number of circles is 373;

- The inter-arc length is 10 pm;

- The smallest radius is 100 pm;

- The largest radius is 15 mm;

- The network pitch is 40 pm;

- The minimum distance between two interconnection bridges is 1000 pm.

Claims (24)

1 - Semi-transparent photovoltaic module consisting of a plurality of photovoltaic cells electrically connected in series, said cells being composed: - active photovoltaic zones (2) contained in arcs of crowns (14) of active crowns, said active photovoltaic zones of the same active crown being separated by isolation zones (4); - vacant spaces (3) forming transparency zones between active zones (2) and arranged in transparent crowns; - two adjacent active rings in a radial direction being separated by a transparent ring (3) and two photovoltaic active areas (2) of adjacent active rings in a radial direction belonging to the same cell being connected by at least one interconnection bridge ( 8) driver; - characterized in that the isolation zones (4) of the same adjacent photovoltaic cell in a radial direction are not located opposite one another. 2 - semi-transparent photovoltaic module according to claim 1, characterized in that the interconnection bridges (8) conductors are not located opposite each other. 3 - semi-transparent photovoltaic module according to any one of the preceding claims, characterized in that the insulation zones (4) are transparent. 4 - Semi-transparent photovoltaic module according to any one of the preceding claims, characterized in that the active rings have all the same geometric shape. 5 - semi-transparent photovoltaic module according to any one of the preceding claims, characterized in that the active rings and the transparent rings are concentric rings. 6 - semi-transparent photovoltaic module according to any one of the preceding claims, characterized in that the active rings are spaced radially by a pitch P _a constant. 7 - Semi-transparent photovoltaic module according to any one of the preceding claims, characterized in that the active rings have a constant width. 8 - semi-transparent photovoltaic module according to any one of the preceding claims, characterized in that the active photovoltaic zones (2) have a constant width CD. 9 - semi-transparent photovoltaic module according to any one of the preceding claims, characterized in that the width of the active photovoltaic zones (2) is between 10 nm and 50 μm. 10 - semi-transparent photovoltaic module according to claim 8, characterized in that the interconnection bridges (8) have a length equal to P _a - CD. 11 - Semi-transparent photovoltaic module according to any one of the preceding claims, characterized in that the width of the concentric rings and the width of the interconnection bridges (8) are of the same order of magnitude. 12 - Semi-transparent photovoltaic module according to any one of the preceding claims, characterized in that the active photovoltaic zones (2) are of the same width as the active rings. 13 - Semi-transparent photovoltaic module according to any one of the preceding claims, characterized in that the interconnection bridges (8) are randomly distributed between two active areas (2) photovoltaic of adjacent active rings radially belonging to the same cell, so that the succession of interconnection bridges does not produce an optical effect visible to the naked eye. 14 - Semi-transparent photovoltaic module according to any one of the preceding claims, characterized in that the total area of all the interconnection bridges (8) does not exceed 10% of the total area of the active areas (2 ) photovoltaic. 15 - semi-transparent photovoltaic module according to any one of the preceding claims, characterized in that the interconnection bridges (8) are formed of thin layers identical to the thin layers of the active areas (2) photovoltaic so that said bridges are not only conductive but also convert the received light energy. 16 - Method for designing the semi-transparent photovoltaic module according to any one of claims 1 to 15 characterized in that it comprises the following steps: 10. Create a working file or image; 11. Choose the initial parameters; 12. Calculate the length of the crown arcs; 13. Calculate the starting angles of the crown arcs (15, 15 ', 15); 14. Calculate the stopping angles of the crown arcs (16, 16 ', 16); 15. Draw the crown arcs from the pre-calculated parameters; 16. Determine the limits of the placement intervals of the interconnection bridges (8); 17. Choose the placement of the interconnection bridges within the intervals; 18. Draw the interconnection bridges (8). 17 - Design method according to claim 16, characterized in that an arc of crowns of index (i, Rk) is defined by its mean radius (R _k ), the width (CD), its starting angle (Âdj , _Rk ) (15,15 ', 15) and its arc length (Larc_k). 18 - Design method according to claim 16 or 17, characterized in that the angle di, _R _k (15, 15 ', 15) is an angle whose value is chosen random between 0 and 2 π / Ν. 19 - Design method according to claim 18, characterized in that for any integer k ranging from 1 to the total number (NB) of crowns, the condition (Âdi, _R _ _k * Âdi, _R _ _k -i) and (Âdi , _R _ _k * Âdi, _R _ _{k +} i) for k> 1 is verified. 20 - Design method according to claim 19, characterized in that for any integer k ranging from 1 to NB and all integer i ranging from 1 to N, the stopping angle (16, 16 ', 16'9 of the layout of the crown arc of index (i, Ri <) is calculated according to: Âa _{i / R} _k = Λ __ Adj + i, _R _k - Qk- 21 - Design method according to claim 20, characterized in that the choice of terminals delimiting the placement interval of the interconnection bridges (8) is defined according to the following substeps: - Define the angular interval Ii by h = [Âdi, _R k + i, Âai, _R _k + i] - Search for the two values among the Âd _{i / R} k and Âa _izR _ _k for i varying from 1 to N which belong to the interval Ii, where  _m in is the smaller of these two values and  _max the larger . O If Amin and  _max have the same index, they are the two limits of the interval delimiting the placement of the interconnection bridges. o Otherwise, we search for the index i of the arc of radius R _k and the two limits of the maximum difference Âdifr such that Âdifr = Max (( _m in - Âdi, _R _k + i), (Aai, _R _k + l Amax)) 22 - Design method according to claim 21, characterized in that the placement of the interconnection bridges (8) is random within the intervals defined by the placement terminals of said interconnection bridges. 23 - Watch, characterized in that it comprises a photovoltaic module according to any one of claims 1 to 15. 24 - Glazing, characterized in that it comprises a photovoltaic module according to any one of claims 1 to 15.