CN216450658U

CN216450658U - Photovoltaic device and assembly

Info

Publication number: CN216450658U
Application number: CN201990001289.5U
Authority: CN
Inventors: 阿兰·斯特拉博尼
Original assignee: Stile
Current assignee: Stile
Priority date: 2018-11-07
Filing date: 2019-11-06
Publication date: 2022-05-06
Anticipated expiration: 2029-11-06
Also published as: EP3878019A1; FR3088140A1; WO2020094980A1; FR3088140B1

Abstract

The utility model relates to a photovoltaic device and an assembly, wherein the photovoltaic device (300) comprises a juxtaposition of elementary cells (302) connected in series by a permeable conductive mesh (304). An assembly comprises a plurality of photovoltaic devices such as defined above connected in parallel between a first terminal and a second terminal of the assembly, wherein each conductive mesh of two adjacent cells connected to the same conductive photovoltaic device one to the other is common to all photovoltaic devices of the assembly.

Description

Photovoltaic device and assembly

RELATED APPLICATIONS

The present patent application claims the benefit of priority from French patent application FR18/71388, which is incorporated herein by reference.

Technical Field

The present disclosure relates to the field of photovoltaic devices, and more particularly to photovoltaic devices including a plurality of interconnected photovoltaic cells.

Background

The present application has provided in french patent application No.16/54518 filed on 20/5/2016 a photovoltaic device comprising a plurality of interconnected elementary photovoltaic cells.

However, it is desirable to at least partially improve certain aspects of known photovoltaic devices.

SUMMERY OF THE UTILITY MODEL

Embodiments therefore provide a photovoltaic device comprising a juxtaposition of elementary cells connected in series by an open-grid conductive web.

According to an embodiment, each conductive mesh has the shape of a grid.

According to an embodiment, each conductive mesh is formed by a plurality of braided conductive wires forming a grid or an integral grid.

According to an embodiment, each conductive mesh is in contact with a first current collecting structure (collector structure) on the front side of a first cell on the one hand, and with a second current collecting structure on the back side of a second adjacent cell of the first cell on the other hand, by its front side.

According to an embodiment, the conductive mesh is not attached to the first and second current collecting structures.

According to an embodiment, each conductive mesh is attached to the first current collecting structure by its edge furthest from the second cell and to the second current collecting structure by its edge furthest from the first cell.

According to an embodiment, the first current collecting structure is a discontinuous conductive pattern formed in a metal layer arranged on top of and in contact with the semiconductor plate of the first cell.

According to an embodiment, adjacent cells are arranged side by side on the same plane.

According to an embodiment, adjacent cells overlap.

According to an embodiment, the width of each web is substantially equal to the width of the elementary cells.

According to an embodiment, the length of each mesh is in the range of one quarter to three quarters of the length of the elementary cells.

According to an embodiment, the elementary cells and the conductive mesh are arranged between a transparent front protective plate and a rear protective plate.

According to an embodiment, the device has the shape of a curved or corrugated plate.

Another embodiment provides an assembly comprising a plurality of photovoltaic devices such as defined above connected in parallel between a first terminal and a second terminal of the assembly, wherein each conductive mesh of two adjacent cells connected to the same conductive photovoltaic device one to the other is common to all photovoltaic devices of the assembly.

Drawings

The foregoing and other features and advantages will be discussed in detail in the following non-limiting description of specific embodiments, taken in conjunction with the accompanying drawings, wherein:

fig. 1A and 1B schematically show an example of an assembly of photovoltaic cells;

FIG. 2 illustrates an embodiment of a current collection structure and connection pads of the photovoltaic cells of the assembly of FIGS. 1A and 1B;

fig. 3A and 3B schematically show an example of an assembly of photovoltaic cells according to a first embodiment;

figure 4 schematically shows an alternative embodiment of an assembly of photovoltaic cells according to the first embodiment;

fig. 5 schematically shows another alternative embodiment of an assembly of photovoltaic cells according to the first embodiment;

fig. 6 schematically shows another example of an assembly of photovoltaic cells according to the first embodiment;

figure 7 schematically shows an alternative embodiment of the connected conductive elements of the assembly of photovoltaic cells according to the first embodiment;

figures 8A and 8B schematically show another alternative embodiment of the connected conductive elements of the assembly of photovoltaic cells according to the first embodiment;

fig. 9 schematically shows an example of an assembly of photovoltaic cells according to a second embodiment;

fig. 10 shows an example of a current collection structure of a photovoltaic cell according to a third embodiment; and is

Fig. 11A and 11B schematically show an example of a photovoltaic device according to a fourth embodiment.

Detailed Description

Like features have been designated by like reference numerals in the various drawings. In particular, structural and/or functional features that are common among the various embodiments may have the same reference numerals and may be arranged with the same structural, dimensional, and material characteristics.

For clarity, only steps and elements useful for understanding the embodiments described herein are shown and described in detail. In particular, the formation of the basic photovoltaic cells forming the described assembly is not described in detail, such cell formation being within the abilities of one skilled in the art based on the indications of the present specification.

Unless otherwise stated, when two elements are referred to as being connected together, this means there is no direct connection of any intervening elements other than conductors, and when two elements are referred to as being coupled together, this means that the two elements may be connected or they may be coupled via one or more other elements.

In the following description, when referring to terms defining absolute position, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or terms defining relative position, such as the terms "above", "below", etc., or terms defining direction, such as the terms "horizontal", "vertical", etc., it is understood that in practice the described device may be oriented differently, unless otherwise specified, with reference to the orientation of the drawings.

Unless otherwise indicated, the expressions "about", "approximately", "substantially" and "approximately" mean within 10%, preferably within 5%, or within 10 °, preferably within 5 °, when they refer to angular orientation or the like.

Fig. 1A and 1B schematically show an example of an assembly 100 of photovoltaic cells 102 of a photovoltaic panel. FIG. 1A is a partial cross-sectional view of the assembly 100 taken along plane A-A of FIG. 1B. Fig. 1B is a perspective view of the back of the assembly 100.

The photovoltaic cells 102 of the assembly 100 are, for example, the same as in the manufacturing dispersion. In the example of fig. 1A and 1B, the cells 102 have the shape of rectangular plates, and are arranged side by side on the same plane. The large sides of adjacent cells are substantially parallel and opposite, and their small sides are aligned.

Hereinafter, the term "length" of a photovoltaic cell of an assembly of cells will designate the dimension of that cell in the direction of alignment of the cells of the assembly, and the term "width" of a cell will designate its dimension in the direction orthogonal to the cell alignment direction. In other words, in the example of fig. 1A and 1B, the length of the battery corresponds to the size of its small side, and the width of the battery corresponds to the size of its large side.

In the example of fig. 1A and 1B, the cell width may be in the range of 51mm (approximately 2 inches) to 210mm (approximately 8 inches), for example, approximately 156mm (approximately 6 inches). The cell length is for example in the range from one tenth of its width to its width.

Each cell 102 comprises a P-doped semiconductor plate 104, which P-doped semiconductor plate 104 comprises an N-doped layer 106 on its front side (i.e. its upper surface in the orientation of fig. 1A). The semiconductor board 104 is made of, for example, silicon. The semiconductor board 104 may be monocrystalline or polycrystalline. The thickness of the plate 104 is, for example, in the range of 100 to 300 μm. The layer 106 extends vertically from the front face of the plate 104, for example across a thickness in the range of 0.05 to 0.1 μm. In a top view, the layer 106 extends over substantially the entire surface of the semiconductor plate 104, for example. The layer 106 may be configured on its front side to capture sunlight. Layer 106 may be further covered with an antireflective layer (not shown).

Each cell 102 also includes an electrically conductive

current collection structure

108 and 110 disposed on top of and in contact with the front side of the semiconductor board 104 and below and in contact with the back side of the semiconductor board 104, respectively. In fig. 1A and 1B, the

current collection structures

108 and 110 are not described in detail. The front side current collecting structure 108 may be a metal layer, for example made of aluminum or silver, which is open to the sun to reach the front side of the semiconductor board 104. As an example, in top view, the surface area of the semiconductor plate 104 covered with the metal layer forming the collecting structure 108 is less than 10% and preferably less than 5% of the total surface area of the semiconductor plate 104, so that a large part of the incident solar radiation reaches the surface of the semiconductor plate 104. As an example, in top view, the current collection structure 108 has the shape of a comb, the teeth of which form electrical contacts with the front face of the layer 106, which electrical contacts are regularly distributed over the entire front face of the layer 106. As a variant, the front side current collection structure 108 is a layer of transparent conductive material (e.g. indium tin oxide) that extends continuously over substantially the entire front side of the semiconductor board 104.

The backside collection structure 110 may be a metal layer, for example made of aluminum or silver, which extends continuously over substantially the entire backside of the semiconductor board 104. If desired, the backside collection structure 110 may be a layer of open metal or transparent conductive material if it is desired that the backside of the photovoltaic cell also collect light, for example by reflection on a surface disposed at the backside of the panel. In this case, the semiconductor plate 104 may comprise on its back surface a doped layer (not shown) having a conductivity type opposite to that of the plate 104, i.e. N-type in this example, for example extending over the entire surface of the plate 104. It is then referred to as a bifacial photovoltaic cell.

In the example of fig. 1A and 1B, the semiconductor plate 104 includes a P-type doped region 112 on its back surface that has a doping level greater than that of the plate 104. The backside current collection structure 110 is in contact with the plate 104 via the region 112. By way of example, structure 110 is an aluminum structure and region 112 is created as a result of aluminum diffusion into plate 104.

In the case of a bifacial photovoltaic cell, the current collection structure 110 is made of silver, for example.

In the example of fig. 1A and 1B, each cell 102 includes a plurality of connection pads 114 disposed on and in contact with the top of the front side current collection structure 108 and a plurality of connection pads 116 disposed on and in contact with the top of the back side current collection structure 110. The

connection pads

114 and 116 are for example based on silver and/or tin. Pads 114, on the one hand, and pads 116, on the other hand, are aligned with the same direction of width in the cell.

The lateral dimensions of the

connection pads

114 and 116 are small compared to the lateral dimensions of the battery. By way of example,

connection pads

114 and 116 each have a length less than half the cell length and a width less than 10% of the cell length. The length and width of the

pads

114 and 116 are less than 3mm, for example.

The cells of the assembly of fig. 1A and 1B are coupled in series by elongated conductive elements 120, such as conductive strips or wires (e.g., made of copper). Each conductive element 120 extends longitudinally in the cell in the same direction as the length. Each conductive element 120 has one end electrically coupled and preferably connected (e.g., soldered) to a pad 116 on the back side of the cell, and the other end soldered to a pad 114 on the front side of an adjacent cell. Where the conductive element 120 is a tape, the width of the tape may be in the range of 0.5 to 3 mm. The thickness of the conductive tape is, for example, in the range of 50 to 200 μm. In the case where the conductive element 120 is a wire, the wire diameter may be in the range of 50 to 500 μm. In the example shown, each cell 102 includes three front side connection pads 114 regularly aligned and regularly distributed with the width co-current in the cell and three back side connection pads 116 regularly aligned and regularly distributed with the width co-current in the cell. Two adjacent cells are then coupled by three parallel conductive elements 120, which are regularly co-distributed with the width in the cell. However, the number of pads 114/116 for each cell and the number of conductive elements 120 coupling two adjacent cells together may be different than three. As an example, each cell 102 includes seven front side connection pads 114 regularly aligned in the cell and regularly distributed with the wide co-direction, and seven back side connection pads 116 regularly aligned in the cell and distributed with the wide co-direction. Two adjacent cells are then coupled by a plurality of parallel conductive elements 120 regularly distributed with a wide codirectional distribution in the cells.

The back side connection pads 116 of each cell are arranged close to the edge furthest from the adjacent cell to which they are connected by conductive elements 120. Thus, the pads 116 of each cell are located in the half of the cell furthest from the adjacent cell connected to those pads. As an example, each pad 116 of a cell 102 is located entirely within 10% of the cell 102 furthest from the adjacent cell connected to the pad. The pads 114 are, for example, vertically arranged in line with the pads 116.

Due to this arrangement of the pads, each conductive element 120 has a free, unsoldered, horizontal portion 124 having a length greater than half the length of the cell, for example about the length of the cell, in addition to an inclined portion 122 coupling the front side of the cell to the back side of an adjacent cell.

At the ends of the cell repeat (not shown), the conductive connecting element 120 may be coupled to other similar components connected in series or parallel to the assembly 100, or to an electronic device such as a power converter.

In operation, when the cells are exposed to sunlight, the current generated by each cell is collected at the front side by the current collection structure 108 and, in the case of a double-sided structure, at the back side by the current collection structure 110. The collected current converges toward the pad 114 and flows through the conductive element 120 toward the pad 116 of the adjacent cell.

Fig. 2 is a top view of the basic photovoltaic cell 102 of the assembly 100 of fig. 1A and 1B, showing an embodiment of the front side current collection structure 108 and the front side connection pads 114 of the cell in further detail.

The current collection structure 108 of fig. 2 has a comb shape comprising a plurality of teeth 203, which teeth 203 are coupled together by continuous or discontinuous collector bars 201, which collector bars 201 extend parallel to the large sides (width) of the cells near the edges of the cells. The width of the collector rail 201 is, for example, in the range of 50 to 200 μm. The teeth 203 of the comb are formed by conductive strips perpendicular to the strip 201 which extend from the strip 201 to the large side of the cell (in the direction of the cell length) opposite the strip 201. The teeth 203 are regularly distributed across the width of the battery. Each tooth 203 has a width in the range of 10 to 100 μm, for example, and preferably in the range of 20 to 50 μm. The repetition pitch of the teeth 203 is, for example, in the range of 1 to 3 mm. The current collection structure 108 of fig. 2 is made of, for example, silver or aluminum. The thickness of the structure 108 is, for example, in the range of 5 to 30 μm. Portions of the protective layer and the antireflective layer (not shown) may be present on the front side of layer 106 between the teeth of the comb. In the example of fig. 2, the battery comprises seven front connection pads 114 arranged along the main strip 201 of the comb, these connection pads 114 being regularly distributed along the strip 201. Each pad 114 is partially located on a strip 201.

More generally, the front side current collection structure 108 may have any other shape suitable for uniformly collecting charge carriers generated in the semiconductor board 104 of the cell and causing them to converge toward the front side connection pads 114 of the cell.

A limitation of the assembly described in connection with fig. 1A and 1B and fig. 2 is that it is relatively complex to form. In fact, soldering the conductive element 120 to the

connection pads

114 and 116 of the elementary cell 102 requires expensive and cumbersome equipment and relatively long execution times.

Furthermore, the soldering of the conductive element 120 to the

connection pads

114 and 116 establishes a rigid mechanical connection between the conductive element 120 and the battery, which may lead to degradation in case of deformation of the photovoltaic panel, for example due to the effect of temperature variations, wind or snow weight.

Furthermore, in the case of a basic cell comprising a current collection structure formed by a metal structure of the open type, for example with respect to a current collection structure of the type described in fig. 2, the conductive pattern of the current collection structure must be chosen so as to be able to cause the collected charge carriers to converge towards the corresponding connection pads of the cell. This imposes limitations on pattern selection that are not necessarily compatible with the need to minimize the surface area of the semiconductor wafer 104 that is hidden by the current collection structure.

In addition, the presence of relatively thick conductive bands or wires 120 at the surface of the battery can detract from the appearance of the assembly.

Furthermore, the surface area of the electrical contact area between the conductive element 120 and the current collection structure and the number of contact points between the conductive element 120 and the current collection structure are relatively small. Therefore, the risk of interruption of the electrical continuity between the conductive element 120 and the current collection structure and, consequently, of loss of efficiency of the assembly is relatively high.

Fig. 3A and 3B schematically show an example of an assembly 300 of photovoltaic cells 302 of a photovoltaic panel according to a first embodiment. Fig. 3A is a partial cross-sectional view of the assembly 300 along the plane a-a of fig. 3B. Fig. 3B is a partial top view of the assembly 300.

The assembly 300 and base cell 302 of fig. 3A and 3B include common elements with the assembly 100 and base cell 102 of fig. 1A and 1B. These common elements will not be described in detail. Hereinafter, only differences with respect to the example described with respect to fig. 1A and 1B and fig. 2 will be highlighted.

The primary cell 302 of fig. 3A and 3B differs from the primary cell 102 of fig. 1A and 1B primarily in that they do not include connection pads 114 on their front side current collection structures 108 and do not include connection pads 116 on their back side current collection structures 110.

In the assembly 300 of fig. 3A and 3B, the cells 302 are connected in series by a permeable conductive mesh 304, for example made of copper, preferably tin-plated copper (i.e. covered with a tin-based alloy). Each conductive mesh 304 extends over a portion of the front side of a cell and under a portion of the back side of an adjacent cell. More specifically, each conductive mesh 304 includes: a portion 304a with its back side in contact with a portion of the front side current collection structure 108 of a cell, and a portion 304b with its front side in contact with a portion of the back side current collection structure 110 of an adjacent cell. Each web 304 also includes, between the

portions

304a and 304b, an inclined portion 304c extending between the opposite large sides of the two adjacent cells to which it connects. Each web 304 extends across substantially the entire width of the cells connected thereto in the same direction as the width in the assembly. As a variant, the width of the web may be limited to only a portion of the cell width. Preferably, the width of the web is at least equal to 90% of the width of the cell. As an example, in each web 304, starting from the large side of the cell closest to the adjacent cell connected to the same web 304, each of the

web portions

304a and 304b extends in the direction of the assembly length over a distance in the range of one quarter to three quarters of the cell length.

It should be noted that for simplicity, in FIG. 3B, only the central web 304 of the component part of FIG. 3A is shown.

Here, the open type conductive mesh means: each mesh 304 includes through-holes that are capable of letting most of the incident sunlight towards the semiconductor board 104. By way of example, each mesh 304 is formed of intersecting conductive wires that form a grid. By way of example, each mesh 304 is formed from braided (non-welded) conductive wires that form a grid. Alternatively, each mesh 304 is formed from a unitary conductive grid. Due to the relatively large dimension of the mesh 304 in the width direction of the assembly, the thickness of the conductive wires forming the mesh 304 may be small, which has the advantage of providing a large flexibility to the mesh 304. As an example, the thickness of the conductive wires forming the mesh 304 is in the range of 10 to 500 μm, for example 50 to 100 μm.

In the example of fig. 3A and 3B, the conductive mesh 304 is in mechanical and electrical contact with the

current collecting structures

108 and 110 of the battery 302, but is not directly attached to the

current collecting structures

108 and 110. In particular, the mesh 304 is not welded or attached to the

current collection structures

108 and 110. Thus, in the event of deformation of the photovoltaic panel, for example under the influence of temperature variations or due to weather, each mesh 304 may slide along the front and/or back of the cells to which it is connected, which enables the electrical connection between the cells to be maintained without mechanical stresses that may damage the cells.

In the example of fig. 3A and 3B, the assembly 300 is protected on its front side by a transparent protective layer 306, for example made of glass or plexiglass, and on its back side by an opaque or transparent protective plate 308. The upper protective layer 306 is not shown in fig. 3B for simplicity. For example, the photovoltaic cell 302 and the connecting mesh 304 are held in compression (compressed) between the

protective plates

306 and 308 to maintain electrical contact between the connecting mesh 304 and the cell 302. As an example, the

protective sheets

306 and 308 may be attached to each other and to the assembly of the photovoltaic cell 302 and the connecting mesh 304 by a lamination process. The use of a lamination process in particular enables the establishment of a uniform residual compressive stress that is typically maintained over a long period of time from several years to several decades. More generally, any other attachment means that enables keeping the battery 302 and the net 304 compressed between the

protective plates

306 and 308 may be used.

An advantage of the assembly of fig. 3A and 3B is that it is easier to form than an assembly based on soldered conductive strips or wires of the type described in connection with fig. 1A and 1B. Indeed, in the embodiment of fig. 3A and 3B, the base battery 302 and the conductive mesh 304 may be positioned using conventional pick and place equipment. It should also be noted that because of the relatively large size of the mesh 304, the relative positioning of the conductive mesh 304 with respect to the battery 302 does not require a high degree of precision.

Furthermore, in the embodiment of fig. 3A and 3B, each conductive mesh 304 is formed with the

current collection structures

108 and 110 of the cells with its connection to electrical contacts regularly distributed along the entire cell width. Therefore, in the case of a current collecting structure formed of a through-hole type metal layer in contact with the front or back surface of the semiconductor board 104, the conductive elements of the current collecting structure do not have to converge toward a small number of connection pads. This is illustrated by fig. 3B, where the front side current collecting structure 108 of the battery has a shape similar to that of fig. 2, but where the main rods 201 of the comb have been removed, the teeth 203 of the comb extending from one large side of the battery to the other. In other words, in the embodiment of fig. 3A and 3B, each current collection structure may be formed by a plurality of patterns regularly distributed over the surface of the semiconductor plate 104 of the battery, wherein the patterns do not have to be connected together without the mesh 304. This enables an increase in the surface area of the semiconductor board 104 that is not masked by the

current collecting structure

108 or 110, and thus improves the cell efficiency.

Another advantage of the embodiment of fig. 3A and 3B is that the conductive webs 304 may be relatively discrete, or even invisible, even at relatively short distances, because they are formed from very thin conductive wires. This enables to improve the appearance of the assembly with respect to solutions based on conductive strips or wires of the type described in relation to fig. 1A and 1B.

Another advantage is that the number of contact points and the effective surface area of contact between the conductive mesh 304 and the current collection structure is very large in terms of electrical reliability. This enables the risk of interruption of electrical continuity within the assembly to be greatly reduced, or even suppressed.

It should be noted that the first embodiment is not limited to assemblies comprising only cells connected in series, but may be more generally applied to any assembly comprising at least two photovoltaic cells connected in series to each other.

Fig. 4 schematically shows an embodiment of an assembly 300 as a variant, the assembly 300 comprising a plurality of elementary cells 302 connected in parallel or in series. More specifically, in this example, the batteries 302 are grouped in a pair of two adjacent batteries connected in parallel, the pair of batteries being connected to each other in series. More specifically, in each pair of adjacent cells connected in parallel, the upper conductive mesh 304 connects the front side of the first cell to the front side of the second cell, and the lower conductive mesh 304 connects the back side of the first cell to the back side of the second cell. Two adjacent pairs are coupled in series by a conductive mesh 304 connecting the front side of the second battery of a first pair with the back side of the first battery of a second pair.

Fig. 5 is a partial simplified top view of another example of an assembly of photovoltaic cells according to the first embodiment.

The assembly of fig. 5 includes M strings 300_ 1.. 300_ M, each string including N series-connected photovoltaic cells 302, M and N being integers greater than or equal to 2. M strings 300_ i (i being an integer ranging from 1 to M) are connected in parallel between the main terminals P + and P-of the assembly. In the example shown, the assembly includes M-4 strings 300_1, 300_2, 300_3, and 300_4, each string including N-8 batteries 302. The described embodiments are of course not limited to this particular case.

In a top view, the photovoltaic cells are arranged in an array of M rows and N columns. Each row of the array corresponds to a string 300-i. Each column of the array includes all cells of the same rank j (j is an integer in the range 1 to N) in the M strings.

Each of the strings 300_ i corresponds to a component that is the same as or similar to the component 300 of fig. 3A and 3B.

However, in the assembly of fig. 5, each conductive mesh 304 of two adjacent cells connected to each other in the same string is common to the M strings 300_ i of the assembly. In other words, each conductive web 304 extends continuously along substantially the entire height of the assembly in the array column direction.

Thus, considering two columns of ranks j and j +1 of the array, the same open conductive mesh 304 extends over a portion of the front side of each cell of rank j of the array and extends under a portion of the front side of each cell of rank j +1 of the array. Thus, the front sides of the M cells of rank j of the assembly are connected together by the same conductive mesh 304 and to the back sides of the M cells of rank j +1 of the assembly.

An advantage of the assembly of fig. 5 is that the parallel electrical connection of the M strings 300_ i is performed not only at the ends of the strings but also at the level of each elementary photovoltaic cell of each string within the array, which enables a better distribution of the collected current.

Another advantage of the assembly of fig. 5 is that it is relatively easy to form. As an example, batteries of the same rank j may be picked and placed simultaneously by a robot, after which a permeable mesh extending continuously along the entire height of the assembly may be positioned, and so on until the assembly is fully molded. It should be particularly noted that the number of conductive meshes 304 to be manipulated is divided by M relative to the assembly of M strings in parallel, where the conductive meshes 304 will not be common to the different strings.

Fig. 6 is a partial sectional view schematically showing another example of an assembly 400 of photovoltaic cells 302 according to the first embodiment. The assembly 400 of fig. 6 includes common elements with the assembly 300 of fig. 3A and 3B. These elements will not be described in detail hereinafter. Thereafter, only the differences between the two components will be highlighted.

In the example of fig. 6, adjacent cells overlap rather than having the cells arranged side-by-side on the same plane. As an example, the size of the overlapping area between two adjacent cells ranges from 1% to 10% of the cell length in the same direction as the length of the assembly. As in the example of fig. 3A and 3B, adjacent cells are connected via a permeable conductive mesh 304, the conductive mesh 304 having: a first portion 304a, the first portion 304a being in contact with a portion of a surface of the front side current collection structure 108 of the cell through a back side thereof; and a second portion 304b, the second portion 304b contacting, through its front surface, a portion of the surface of the back side current collection structure 110 of an adjacent cell. As in the example of fig. 6, each mesh 304 also includes a portion 304c between the

portions

304a and 304b in the overlap or footprint between the two cells it connects, the portion 304c being in contact with the current collection structure 108 of the first cell by its back side and in contact with the current collection structure 110 of the second cell by its front side.

It should be noted that the embodiments of fig. 5 and 6 may of course be combined.

Fig. 7 shows an alternative embodiment of the electrically conductive connecting mesh 304 of the assembly of photovoltaic cells according to the first embodiment. In particular, the connecting network 304 of fig. 7 may be used in assemblies of the type described above in connection with fig. 3A and 3B through 6.

In the example of fig. 7, the mesh 304 includes, in its portion 304a, a conductive adhesive strip 351 along the edge of the mesh furthest from the second cell connected to the mesh (not shown in fig. 7), facing the first cell connected to the mesh (not shown in fig. 7), and, in its portion 304b, a conductive adhesive strip 353 along the edge of the mesh furthest from the first cell connected to the mesh, facing the second cell connected to the mesh.

The conductive

adhesive strips

351 and 353 are, for example, metal strips made of copper, coated with a metal alloy suitable for melting and mixing with the metal of the

current collecting structures

108 and 110 during lamination of the

protective plates

306 and 308.

The advantage of the variant of fig. 7 is that it enables a further reduction in the risk of interruption of the electrical continuity within the assembly, by gluing the conductive connection mesh 304 to the current collection structure of the photovoltaic cell. Due to the placement of the conductive adhesive strips along both edges of the web parallel to the width of the assembly, a portion of portion 304a of web 304 remains freely displaced with respect to the first cell, and a portion of portion 304b of web 304 remains freely displaced with respect to the second cell. Thus, the advantages of flexibility of the assembly and relative mobility of the batteries with respect to each other within the assembly (particularly in the same direction as the length in the battery) are retained. As an example, the width of each of the conductive adhesive stripes 351 and 353 (i.e. in the cell length direction) is less than 20% of the total dimension of the web in that direction. Furthermore, although the

strips

351 and 353 are shown in fig. 7 as solid conductive strips, the embodiments described are not limited to this particular case. As a variation, each of the conductive

adhesive stripes

351 and 353 may correspond to a through-air portion of the mesh 304. In other words, each open-type conductive mesh 304 may include:

in the left part of the mesh, a first open mesh part coated with a metal alloy suitable for melting and mixing with the metal current collecting

structures

108 and 110 during lamination of the

protective plates

306 and 308;

-in the right-hand part of the mesh, a second open mesh part coated with a metal alloy; and

-in the central part of the mesh, a third open mesh part not coated with a metal alloy.

Fig. 8A and 8B show another alternative embodiment of the electrically conductive connection network 304 of the assembly of photovoltaic cells according to the first embodiment. Unlike the previously described example in which the conductive mesh 304 has a substantially rectangular shape in plan view, in the example of fig. 8A and 8B, the

portions

304a and 304c of the mesh 304 have a toothed or saw-toothed shape.

More specifically, in this example, the portion 340a of the mesh 304 includes a plurality of teeth or serrations 305a extending in the cell length direction, e.g., regularly distributed along the width of the mesh, on the side of the mesh furthest from the second cell (not shown in fig. 8A and 8B) connected to the mesh. Furthermore, in this example, the portion 304c of the mesh 304 comprises a plurality of teeth or serrations 305c extending in the cell length direction, e.g. regularly distributed along the width of the mesh, on the side of the mesh edge furthest from the first cell (not shown in fig. 8A and 8B) connected to the mesh. Between two adjacent teeth 305a of the mesh 304, the upper surface of the first battery connected to the mesh 304 is not covered by the mesh. Further, between two adjacent teeth 305c of the mesh 304, the lower surface of the second battery connected to the mesh is not covered by the mesh.

The conductive patterns of the front and back side collection structures of the elementary cells are chosen such that each conductive element of the pattern is connected to at least one tooth 305a or 305b of the mesh 304. For example, such a serrated conductive mesh is well suited for connection of a battery provided with a current collecting structure of the type described below with respect to fig. 10.

As shown in fig. 8A, for example,

teeth

305a and 305c each extend substantially entirely along the length of

web portions

304a, 304c, respectively. As a variant, as shown in fig. 8B, the

teeth

305a and 305c each extend along a length less than the length of the

portions

304a, 304c of the mesh, respectively.

In the example shown in fig. 8A and 8B, both

portions

304a and 304c of the mesh are provided with teeth or serrations. As a variant, only one of the two

portions

304a and 304c of the net may be provided with teeth or serrations.

An advantage of the variant of fig. 8A and 8B is that it enables to increase the surface area of the cell not covered by the mesh 304 and thus to increase the efficiency of the cell. In addition, this variation enables conductive material savings in forming the mesh 304.

Fig. 9 is a sectional view schematically and partially showing an embodiment of an assembly 600 of photovoltaic cells 302 of a photovoltaic panel according to a second embodiment. The assembly 600 of fig. 9 includes common elements with the assembly 400 of fig. 6. These common elements will not be described again hereinafter. Hereafter, only the differences with respect to the components of fig. 6 will be highlighted.

In the same manner as in the assembly 400 of fig. 6, adjacent elementary cells 302 in the assembly 600 of fig. 9 overlap. In contrast to assembly 400, however, assembly 600 does not include a conductive mesh coupling adjacent cells in series two by two.

In the embodiment of fig. 9, the front side current collection structure of a cell is in direct mechanical and electrical contact with the back side current collection structure of an adjacent cell in the region of overlap between two cells. This enables the series connection of the cells of the assembly to be ensured directly without intermediate connecting elements between the cells.

In assembly 600, the contact between the front and back side current collection structures of the cells in the overlap region between adjacent cells is a sliding contact. In other words, the front side of the lower cell is not attached to the back side of the upper cell in the overlap region between two adjacent cells. In particular, the front side current collection structure 108 of the lower cell is not welded or glued to the back side conductive structure 110 of the upper cell.

The assembly 600 is therefore advantageous in that, in the event of deformation of the photovoltaic panel, for example during manufacture and in particular during the lamination phase of the protective sheet of the panel, under the influence of temperature variations, or due to weather, each cell 302 can slide along the front and/or rear face of the adjacent cell to which it is connected, which enables the electrical connection between the cells to be maintained without mechanical stresses that could damage the cells.

Another advantage of the assembly of fig. 9 is that it is particularly simple to manufacture, since there are no intermediate connecting elements between the cells and no welds, conductive glues or conductive adhesives. Automated and fast battery mounting equipment, such as pick and place equipment, can thus be used simply and easily.

In addition, elimination of ribbon or conductive wire bonding on the cell as a source of defects results in better cell conversion efficiency, and better aging behavior.

Furthermore, because there are no conductive strips or wires and connection pads, a significant amount of conductive material can be saved, which reduces the cost of the battery and the carbon footprint associated with battery manufacturing. The screen printing step typically provided in the manufacture of batteries of the type described in relation to fig. 1A and 1B to form the

connection pads

114, 116 may be further avoided.

As in the examples of fig. 3A and 3B to fig. 8A and 8B, the elementary cells 302 of the assembly 600 may be held by any mechanical support suitable to avoid too large displacements of the cells with respect to each other, to ensure that the electrical connection between the cells is maintained. As in the examples of fig. 3A and 3B through 8A and 8B, the primary cells 302 of the assembly 600 are held in compression, for example, between the front protective plate 306 and the back protective plate 308.

In the embodiment of fig. 9, the front side current collection structure 108 and the back side current collection structure 110 of the cells are selected such that all conductive elements of the front side current collection structure 108 of each cell are connected to the back side current collection structure of an upper adjacent cell in the overlap region between the two cells, and such that all conductive elements of the back side current collection structure 110 of each cell are connected to the front side current collection structure of a lower adjacent cell in the overlap region between the two cells. Preferably, the back side current collecting structure 110 of each cell 302 is a metal layer, e.g., made of silver, tin, or aluminum, that extends continuously over substantially the entire back side of the cell. The front side current collecting structure 108 of each cell is, for example, a metal mesh of open type, for example made of silver or aluminum, so that all elements of the conductive pattern of the structure extend up to the overlapping area of the cell with the upper adjacent cell. For example, the conductive pattern of the front side current collection structure 108 of the base cell 302 may be a pattern of the type described above with respect to fig. 2 or fig. 3A and 3B, or may also be a lobed pattern of the type described with respect to fig. 4 of the above-mentioned french patent application N ° 16/54518.

Fig. 10 is a top view of a basic photovoltaic cell 602 of an assembly of photovoltaic cells according to a third embodiment. The base battery 602 of fig. 10 includes a common battery with the

base batteries

102 and 302 previously described. These common cells will not be described further below. Thereafter, only the differences with respect to the

basic cells

102 and 302 will be highlighted.

The primary difference between the cell 602 of fig. 10 and the

cells

102 and 302 described previously is the shape of its front side current collection structure 108.

The front side current collecting structure 108 of the cell 602 is formed of a permeable metal layer, for example made of silver or aluminum, which is in contact with the front side of the semiconductor layer 106 of the cell.

The current collection structure 108 of the cell 602 is formed by one or more occurrences of the basic conductive pattern 610, which in top view comprises:

a straight main conductive strip 614 extending longitudinally in the cell from the edge of the cell, along approximately half of the cell length, co-directionally with the length; and

a plurality of secondary conductive strips 616, having a width less than the width of the main strips 614, extending from the periphery of the strips 614.

In the example shown, the current collection structure 108 of the cell 602 includes 5 occurrences of the basic conductive pattern 610, which are regularly distributed along the width of the entire cell. The differently appearing primary conductive bars 614 of the primary pattern 610 all begin from the same edge of the cell (the right edge in the orientation of fig. 10). The adjacent occurrences of the primary pattern 610 have secondary conductive strips that meet such that the conductive pattern of the current collecting structure 108 is continuous.

As an example, the width of the main conductive stripe 614 of the basic pattern 610 is in the range of 0.2 to 1 mm. The width of each secondary conductive strip 616 of the basic pattern is, for example, in the range of 10 to 100 μm. The width of the secondary conductive strips is for example in the range of 10 to 50 μm. The thickness of the structure 108 is, for example, in the range of 10 to 30 μm.

In this example, each primary conductive pattern 610 is inscribed within a rectangle 612 in top view, the rectangle 612 having two

sides

612a and 612b substantially parallel to the cell length, the length of which is substantially equal to the cell length, and two

sides

612c and 612d substantially parallel to the cell width, the length of which is substantially equal to the cell width or a divisor of the cell width. Main conductive strip 614 extends from the center of side 612c (orthogonal to side 612c) along approximately half the length of

sides

612a and 612b toward side 612 d. The secondary conductive strip 616 extends from the longitudinal edge of the primary strip 614 and from the end of the primary strip 614 opposite the side 612c all the way to the

sides

612a, 612b, and 612d of the rectangle 612. The ends of the secondary conductive strip 616 are opposite the primary conductive strip 614, regularly distributed along the

sides

612a, 612b, and 612d of the rectangle 612. The conductive pattern 610 is, for example, symmetrical with respect to a central longitudinal axis of the main conductive bar 614. In this example, the conductive pattern 610 includes a plurality of bent secondary conductive strips 616, the secondary conductive strips 616 extending from the end of the strip 614 opposite the edge 612c to the edge 612d and half of the

edges

612a and 612b furthest from the edge 612c and forming a pattern with the main strip 614 in the shape of a dandelion seed. The conductive pattern 610 of fig. 10 further includes a plurality of secondary rectilinear conductive strips 616 substantially orthogonal to the main strips, extending at regular intervals on either side of the main strip 614 from the longitudinal edges of the main strip 614 to the

sides

612a and 612b of the rectangle 612. The lengths of the secondary conductive strips 616 of the pattern 610 are all of the same order of magnitude. As an example, the length of the secondary conductive strips 616 of the pattern are all equal to or more or less within 30%.

Thus, an advantage of the primary conductive pattern 610 of fig. 10 is that all of the charge collected by the secondary conductive strip 616 at the periphery of the rectangle 612 travels substantially the same distance via the secondary conductive strip 616 before reaching the primary conductive strip 614. This results in a particularly efficient collection of charge carriers generated by the light at the cell surface and a particularly uniform distribution of the collected current, which enables an increase in the cell efficiency.

A current collection structure that is the same as or similar to the structure 108 of fig. 10 may also be used as the back side current collection structure 110 of the photovoltaic cell.

The photovoltaic cell 602 of fig. 10 can be used in any type of photovoltaic cell assembly. As an example, the battery 602 may be used in an assembly of the type described with respect to fig. 1A and 1B, in which case the connection pads 114 may be arranged on top of and in contact with the upper surface of the main conductive strip 614 of each primary conductive pattern 610 of the current collection structure 108, for example near the edge 612c of the pattern. As a variant, the battery 602 may be used in an assembly of the type described in relation to fig. 3A and 3B or fig. 4, or also in an assembly of the type described in relation to fig. 9, in which case the connection pads 114 may be omitted.

Fig. 11A and 11B show an example of a photovoltaic device 700 according to a fourth embodiment. Fig. 11A is a simplified perspective view of the front of the device, and fig. 11B is an enlarged partial cross-sectional view of the device taken along plane B-B of fig. 11A.

The device 700 of fig. 11A and 11B has the shape of a corrugated plate and includes a plurality of elementary cells 702 connected in series. The primary battery 702 of the device 700 is, for example, the same or similar battery as the battery 102, which is connected in series by conductive elements similar to those described with respect to fig. 1A and 1B. As a variant, the elementary cells 702 of the device 700 are the same or similar cells as the cells 302, connected in series by a permeable conductive mesh, similar to that described with reference to fig. 3A and 3B to fig. 8A and 8B. The primary battery 702 of the device 700 may also be the same or similar battery as the battery 602 of fig. 10, connected in series by conductive straps or by a permeable conductive mesh.

In the example of fig. 11A and 11B, the corrugation direction of the device 700 is parallel to the length of the battery assembly 702. In other words, the base cell 702 is slightly curved co-directionally with the length to follow the curvature of the device, but not co-directionally with the width.

Preferably, the length of each cell is relatively small compared to the minimum radius of curvature of the device, for example, for a cell thickness of about 200 μm, the minimum radius of curvature of the plate is in the range of one tenth to one twentieth. Thus, the curvature of the battery 702 remains limited. However, it is possible to provide for the use of thinner batteries, for example, having a thickness in the range of 80 to 120 μm, to enable an increase in the length thereof. As an example, for a cell having a thickness of about 80 μm, the cell length may be in the range of one third to one fifth of the minimum radius of curvature of the plate.

In the example of fig. 11A and 11B, the device comprises a transparent corrugated front protective sheet 704 (e.g. made of glass or perspex) and a transparent or opaque corrugated back protective sheet 706. At least one of the

protective sheets

704 and 706 is a rigid sheet to obtain a photovoltaic panel in the shape of a rigid corrugated sheet.

As an example, the

protective sheets

704 and 706 may be attached to each other and to the components of the photovoltaic cell 702 by a lamination process. More generally, any other suitable method may be used. An adhesive and/or filler material, not shown, may be provided between the

protective plates

704 and 706, particularly at the periphery of the assembly, to ensure the hermeticity of the assembly.

In fig. 11B, electrical connectors 708 coupling the front side of each cell to the back side of an adjacent cell have been schematically illustrated. As indicated above, it will be understood that these connectors may correspond to conductive elements such as described with respect to fig. 1A and 1B, or to conductive meshes such as described with respect to fig. 3A and 3B to fig. 8A and 8B.

An advantage of the device 700 of fig. 11A and 11B is that it can be used directly as a roof element, for example, to replace conventional tiles or slates. Preferably, the height and spacing of the corrugations is compatible with conventional roofing elements, such as tiles, to enable the use of panels 700 in combination with such conventional roofing elements. As an example, the height (or amplitude) of the corrugations is in the range of 5 to 15cm, and the pitch (or period) of the corrugations is in the range of 15 to 30 cm.

As a variant, the device 700 may have the shape of a curved plate, for example, having the shape of a simple brick (i.e. comprising a single corrugation period).

Various embodiments and modifications have been described. Those skilled in the art will appreciate that certain features of these embodiments may be combined, and that other variations will readily occur to those skilled in the art. In particular, the described embodiments are not limited to the examples of dimensions and materials mentioned in the present disclosure.

Furthermore, although the photovoltaic cells described each comprise a P-doped semiconductor plate 104, but provided with an N-doped layer on its front side, each cell may alternatively comprise an N-doped semiconductor plate provided with a P-doped layer on its front side.

Claims

1. A photovoltaic device (300; 400) comprising a juxtaposition of elementary cells (302) connected in series by a permeable conductive mesh (304),

wherein each conductive mesh (304) is formed of intersecting conductive wires forming a grid;

wherein each conductive web (304) is in contact with a first front side current collecting structure (108) of a first cell by its back side on the one hand and with a second back side current collecting structure (110) of a second cell adjacent to the first cell by its front side on the other hand, and

wherein in each conductive mesh (304), a portion (304a) of the mesh in contact with the first front side current collecting structure (108) extends over a distance in the range of one quarter to three quarters of the length of a first cell in the direction of the length of the assembly, and a portion (304c) of the mesh in contact with the second back side current collecting structure (110) extends over a distance in the range of one quarter to three quarters of the length of an adjacent second cell in the direction of the length of the assembly.

2. The device (300; 400) according to claim 1, wherein each conductive mesh (304) has the shape of a grid.

3. The device (300; 400) according to claim 2, characterized in that each conductive mesh (304) is constituted by a plurality of braided conductive wires forming a grid or by an integral grid.

4. The apparatus (300; 400) of claim 1, wherein the conductive mesh (304) is not attached to the first and second current collecting structures (108, 110).

5. The device (300; 400) of claim 1, wherein each conductive mesh (304) is attached to the first current collecting structure (108) by its edge furthest from the second cell and to the second current collecting structure (110) by its edge furthest from the first cell.

6. The device (300; 400) according to any of claims 1 to 5, wherein the first current collecting structure (108) is a discontinuous conductive pattern formed in a metal layer arranged on and in contact with a front side of a semiconductor plate (104) of the first cell.

7. The device (300) according to any one of claims 1 to 5, wherein adjacent cells (302) are arranged side by side on the same plane.

8. The device (400) of any of claims 1 to 5, wherein adjacent cells (302) overlap.

9. The device (300; 400) according to any one of claims 1 to 5, characterized in that the width of each mesh (304) is substantially equal to the width of the elementary cells (302).

10. The device (300; 400) according to any one of claims 1 to 5, characterized in that the length of each mesh (304) is in the range of one quarter to three quarters of the length of the elementary cells (302).

11. The device (300; 400) according to any one of claims 1 to 5, wherein the elementary cells (302) and the conductive mesh (304) are arranged between a transparent front protective plate (306) and a rear protective plate (308).

12. The device (700) according to any of claims 1 to 5, wherein the device is in the shape of a curved or corrugated plate.

13. An assembly characterized in that it comprises a plurality of photovoltaic devices (300_1, 300_2, 300_3, 300_4) according to any one of claims 1 to 5 connected in parallel between a first terminal (P +) and a second terminal (P-) of the assembly, wherein each conductive net (304) connecting two adjacent cells (302) of the same photovoltaic device (300_ i) to each other is common to all photovoltaic devices (300_ i) of the assembly.