photovoltaic cell element, photovoltaic cell and manufacturing processes for such elements and cells

Abstract

Title: Photovoltaic cell element, photovoltaic cell and manufacturing processes for such elements and cell. Photovoltaic cell element, comprising a photovoltaic cell substrate (4) configured to generate electrons upon receipt of light radiation, an outer contour and an inner contour delimiting the substrate (4), the element being devoid of material outside the outer contour and inside the inner contour, the substrate (4) comprising a starter trench (12) formed at least partially on a surface (5) of the substrate (4). Figure for the abstract: Fig. 9

Description

Title of the invention: photovoltaic cell element, photovoltaic cell and methods of manufacturing such element and cell Technical field

[0001] The present invention relates to the field of photovoltaic cells. It finds a particularly advantageous application for the production of photovoltaic cells having unconventional geometric shapes such as shapes having a hollowed-out internal part, for example rings. STATE OF THE ART

[0002] Generally, a photovoltaic cell converts a portion of light radiation into electrical energy. A photovoltaic cell comprises a substrate configured to generate electrons upon receipt of light radiation, a first electrically conductive structure on a first surface of the substrate and a second electrically conductive structure on a second surface of the substrate, opposite the first surface. Each surface layer generally allows the preferred collection of a type of carrier (electrons or holes). The substrate mainly used comprises silicon.

[0003] Mention may be made of certain very high-efficiency photovoltaic cells, for example HET type cells (i.e. heterojunction type) and TOPCon type cells (Tunnel Oxide Passivated Contact). In particular, a HET type cell is a cell comprising a layer of a crystalline substrate and at least one layer of hydrogenated amorphous silicon in contact with the crystalline substrate layer.

[0004] There are a great many devices incorporating photovoltaic cells, and they require photovoltaic cells of very variable sizes and also very variable shapes.

[0005] There is therefore a general need to produce photovoltaic cells of unconventional shapes. Conventional photovoltaic cell shapes are generally discs or squares, with protruding or rounded edges.

[0006] It may also be necessary to use photovoltaic cells for various devices, such as roller shutters or connected objects, in particular for small devices, such as calculators, etc.

[0007] There are a number of industrial solutions for cutting photovoltaic cells. The most widely used technology is still the use of a laser to create a trench in the silicon, followed by cutting with mechanical cleavage, i.e. a physical separation of the two parts of the cell.

[0008] However, cutting causes electrical losses, which are relatively significant for high-efficiency cells. This is even more true for small cells, where the effect of the cut edge becomes very significant relative to the total surface area of ​​the cell. Indeed, it is observed that the smaller the size of a cell obtained by cutting, the more the electrical losses increase. Furthermore, the greater the incident energy of the laser used for cutting, the more the final performance of the cell is degraded. Indeed, the impact of the temperature generated by the laser is significant, and the use of a high-power laser, necessary to ensure good cutting, does not make it possible to obtain cells with sufficient electrical performance. Optimizing the cutting may consist of using successive passes to reduce the impact of each laser shot.However, a final degradation is observed, all the more significant as the trench to be generated for a clean cut must be deep.

[0009] An object of the invention is to provide means for providing a photovoltaic cell element having satisfactory performance.

[0010] Another object is to provide means for providing a photovoltaic cell element suitable for integration within a small-sized device. SUMMARY

[0011] To achieve these objectives, a method of manufacturing at least one photovoltaic cell element is proposed, comprising: - a supply of a photovoltaic cell substrate configured to generate electrons upon receipt of light radiation; and - a generation of a so-called external trench on a surface of the substrate to form an external contour delimiting a first part of the substrate outside the external contour.

[0012] The method further comprises: - generation of a so-called internal trench on the surface of the substrate to form an internal contour delimiting a second part of the substrate inside the internal contour and a third part of the substrate between the external and internal contours; - generating a primer trench on the surface of the substrate, the primer trench being formed at least partially in at least one portion of the substrate among the second and third portions of the substrate; and - a so-called internal separation comprising a mechanical separation of the second part with the third part so as to obtain at least one photovoltaic cell element from the third part of the substrate.

[0013] Thus, a method is provided that is particularly suitable for obtaining photovoltaic cell elements having complex shapes, in particular geo shapes. unconventional metrics, such as round, triangle, ring, hexagon, etc. In addition, such a method makes it possible to obtain elements having a hollowed-out part of material, for example at the heart of the element. The proposed method makes it possible to obtain a possibly complex shape, for example hollowed-out, with a considerably reduced risk of breakage. Furthermore, this method including a starter trench facilitates in particular the mechanical separation of the second and third part, and therefore allows a significant reduction in the trench depth necessary for the separation of the different parts of the substrate. As a result, the incident laser power necessary to produce the internal and / or external trench(es) is also greatly reduced. The proposed method thus makes it possible to reduce the degradation of the substrate caused by the laser power.Ultimately, the proposed process thus makes it possible to improve performance, in particular the efficiency of photovoltaic cells with complex shapes.

[0014] According to another aspect, there is provided a method of manufacturing a photovoltaic cell, comprising a manufacturing of at least one photovoltaic cell element as defined above and at least one metallization, carried out before or after the internal separation, the metallization comprising a formation of a first electrically conductive structure on a first surface of the substrate and of a second electrically conductive structure on a second surface of the substrate, opposite the first surface.

[0015] According to another aspect, there is provided a photovoltaic cell element, comprising a photovoltaic cell substrate configured to generate electrons upon receipt of light radiation, an outer contour and an inner contour delimiting the substrate, the element being devoid of material outside the outer contour and inside the inner contour and the substrate comprises a seed trench formed at least partially on a surface of the substrate.

[0016] According to another aspect, there is provided a photovoltaic cell, comprising a photovoltaic cell element as defined above, and a first electrically conductive structure located on a first surface of the substrate and a second electrically conductive structure located on a second surface of the substrate, opposite the first surface. BRIEF DESCRIPTION OF THE FIGURES

[0017] The aims, objects, as well as the characteristics and advantages of the invention will emerge more clearly from the detailed description of embodiments and implementations thereof, illustrated by the following accompanying drawings in which:

[0018] [Fig.l]

[0019] [Fig.2]

[0020] [Fig.3]

[0021] [Fig.4]

[0022] [Fig.5]

[0023] [Fig.6]

[0024] [Fig.7]

[0025] [Fig.8]

[0026] [Fig.9] Figures 1 to 9 schematically illustrate the main stages of a method of implementing a method of manufacturing a photovoltaic cell element; and

[0027] [Fig. 10]

[0028] [Fig. 11]

[0029] [Fig. 12]

[0030] [Fig. 13]

[0031] [Fig. 14]

[0032] [Fig. 15]

[0033] [Fig. 16]

[0034] [Fig. 17]

[0035] [Fig. 18] Figures 10 to 18 schematically illustrate other methods of placing implementation of a method for manufacturing a photovoltaic cell element.

[0036] The drawings are given as examples and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily on the scale of practical applications. DETAILED DESCRIPTION

[0037] Before beginning a detailed review of embodiments of the invention, optional features which may possibly be used in combination or alternatively are set out below: - According to one example, the initiator trench opens into a main zone of the internal trench and the internal separation includes generation of a crack that propagates along the initiator trench and along the internal trench. - According to one example, the primer trench extends into the third part of the substrate, opening into the external trench. - According to one example, the primer trench is formed partially in the second and third parts of the substrate. - According to one example, the primer trench extends into the second part of the substrate from the main area to a secondary area of ​​the trench internal, the starter trench also opening into the secondary zone. In one example, the primer trench extends into the second and third portions of the substrate from a first area of ​​the outer trench to a second area of ​​the outer trench, the primer trench further opening into the first and second areas. According to one example, the internal separation comprises a mechanical separation of the third part of the substrate into at least two distinct portions of the substrate so as to obtain at least two photovoltaic cell elements from respectively said at least two distinct portions of the substrate. According to one example, the method comprises a connection between at least two distinct portions of the substrate to provide a same photovoltaic cell element. In one example, the initiator trench is formed partially in the third portion of the substrate by opening into the outer trench and the internal separation includes generation of a crack that propagates along the inner trench. According to one example, at least one of the outer, inner, and primer trenches is a trench made in a non-through manner within the substrate. In one example, the generation of the internal trench forms a closed internal contour. In one example, the generation of the external trench forms a closed external contour. In one example, the generation of the seed trench creates a partly straight seed trench. According to one example, the method comprises, after the generation of the external trench and before the generation of the seed trench, a so-called external separation, comprising a mechanical separation of the first part with the third part. According to one example, the method comprises, after the internal separation, a so-called external separation, comprising a mechanical separation of the first part with the third part. According to one example, the method comprises, before the external separation, generating an initial trench on the surface of the substrate, in the first portion of the substrate and opening into the external trench. According to one example, the method comprises, after providing the substrate and before the internal separation, generating an additional trench on the surface of the substrate and in the second portion of the substrate to form an additional contour delimiting a fourth portion of the substrate within the additional contour, and mechanically separating the fourth portion from the second portion. - According to one example, the starter trench opens into the internal trench and into the additional trench.

[0038] Figures 1 to 18 show the main steps of a method for manufacturing at least one photovoltaic cell element 1 to 3. A cell element 1 to 3 is intended to manufacture a photovoltaic cell 30, in particular a very high-efficiency cell of the HET or TOPCon type. Generally, the method comprises providing a photovoltaic cell substrate 4 configured to generate electrons upon receipt of light radiation, illustrated in [Fig. 1]. The dimensions of the substrate 4, in length along an X axis, and in width along a Y axis perpendicular to the X axis, are at least greater than those of the elements 1 to 3 to be manufactured. The substrate 4 may come from a “wafer”, in English, that is to say a slice or plate of a monocrystalline semiconductor material, preferably silicon, used to manufacture microelectronic components.After a cleaning step, layers of amorphous silicon can be deposited on each surface of the wafer. For example, the thickness of the substrate 4, along a Z axis perpendicular to the X and Y axes, is between 70 and 200 pm.

[0039] Furthermore, the method comprises a generation of a so-called external trench 10 and a generation of a so-called internal trench 11, as illustrated in [Fig.2].

[0040] The external trench 10 is made on a first surface 5 of the substrate 4 to form an external contour delimiting a first part 20 of the substrate 4 outside the external contour. The internal trench 11 is made on the first surface 5 of the substrate 4 to form an internal contour delimiting a second part 21 of the substrate 4 inside the internal contour and a third part 22 of the substrate 4 between the external and internal contours. The internal trench 11 can be made after, or before, the making of the external trench 10.

[0041] In [Fig.2], an example is shown in which several internal trenches 11 and several external trenches 10 are generated, so as to generate several third parts 22 from the same substrate 4.

[0042] More particularly, the method comprises generating a primer trench 12 on the first surface 5 of the substrate 4, as illustrated in FIGS. 8 and 10 to 15, the primer trench 12 being formed at least partially in at least one portion of the substrate 4 among the second and third portions 21, 22 of the substrate 4. The primer trench 12 may be made before or after making the external trenches 10 and internal 11, or after one of the external 10 or internal 11 trenches.

[0043] The method further comprises a so-called internal separation SI, as illustrated in [Fig.9]. The internal separation SI comprises a mechanical separation of the second part 21 with the third part 22 so as to obtain at least one photovoltaic cell element 1 to 3 from the third part 22 of the substrate 4. In general, the internal separation SI comprises a generation of a crack which propagates at least along the internal trench 11 and causes the physical separation of the second part 21 with the third part 22.

[0044] The starter trench 12 makes it possible to facilitate the internal separation SL. More particularly, the starter trench 12 makes it possible to limit the formation of cracks at the level of the third part 22, also noted active part, that is to say the part of the substrate 4 intended to manufacture the photovoltaic cell element 1 to 3. A crack corresponds to an untimely cracking on the surface of the substrate 4, can significantly reduce the capacities of the third part 22 or break the photovoltaic cell 1 to 3 in the case where the cracks are too significant. Indeed, during the internal separation SI and in the absence of the starter trench 12, cracks can propagate at the level of the third part 22. The starter trench 12 thus makes it possible to limit the rate of breakage of the third part 22 during the internal separation SL.

[0045] Thus, an element 1 to 3 is obtained which may have an unconventional geometric shape, such as a round, triangle, ring, hexagon, etc., as illustrated in [Fig. 18]. A conventional geometric shape of a photovoltaic cell is understood to mean a quadrilateral shape, such as a square, a rectangle or a rhombus. In addition, an element having a hollowed-out portion, i.e. a free space devoid of material, at the heart of the element 1 to 3 can easily be obtained.

[0046] Generally, at least one trench among the external 10, internal 11 and primer 12 trenches is a trench made in a non-through manner within the substrate 4. Preferably, the trenches 10 to 12 are non-through within the substrate 4. By non-through trench is meant a trench having a depth within the substrate 4, along the Z axis, of between 1 / 3 and ¾ of the thickness of the substrate 4, preferably of between ¾ and ¾ of the thickness of the substrate 4. For example, a width of a trench 10 to 12, taken along the X axis, may be between 5 μm and 50 μm, preferably between 10 μm and 25 μm.Furthermore, the starter trench 12 makes it possible to avoid making internal and external trenches 10, 11 through, or more generally makes it possible to reduce the depth of the internal and external trenches 10 and 11 necessary for easy separation of the second and third parts 21 and 22 while minimizing the generation of cracks or untimely breakages and the degradation of the performance of the photovoltaic cells by the generation process. trenches. For example, trenches 10 to 12 are made using a laser. The seed trench 12 therefore makes it possible to reduce the energy of the laser used to make trenches 10 to 12 and limit the associated degradation. According to one embodiment, the internal and external trenches 10, 11 are made using a laser whose wavelength is green, for example the wavelength is equal to 532 nm, the speed is between 10 and 25 mm / s and the power is between 2.2 and 2.8 W. Advantageously, the external and internal trenches 10, 11 are generated using four to eight successive passes of the laser. To make the starter trench 12, a laser with a green wavelength can be used, for example the wavelength is equal to 532 nm, the speed is between 20 and 25 mm / s, the power is between 2.9 and 3.1 W, with two to three successive passes of the laser.Furthermore, the starter trench 12 makes it possible to limit the number of passes of the laser to produce the trenches 10 to 12 to limit untimely damage to the substrate 4. For example, it will be possible to use laser powers greater than 3 W. The generation of the starter trench 12 also makes it possible to reduce the depth of the external 10 and internal 11 trenches, and also of the starter trench 12 itself, and therefore to reduce the energy of the laser used by reducing the number of passes. The starter trench 12 therefore makes it possible to reduce the energy of the laser used, in particular by reducing the number of passes and by increasing the speed of passes, while preserving the electrical performance of the third part 22.

[0047] For example, the generation of the internal trench 11 forms a closed internal contour. Advantageously, the generation of the external trench 10 forms a closed external contour. According to one embodiment, the generation of the primer trench 12 creates a partly rectilinear primer trench 12. Preferably, the primer trench 12 is rectilinear. Thus, it is not necessary to stop firing the laser to change direction.

[0048] In Figures 8 and 11 to 15, different embodiments of a starter trench 12 are shown, in which the starter trench 12 opens into a main zone 13 of the internal trench 11 and the internal separation SI comprises a generation of a crack which propagates along the starter trench 12 and along the internal trench 11. In general, the generation of the starter trench 12 can be carried out between the step of generating several third parts 22 from the same substrate 4, as illustrated in [Fig. 2], and the step of the so-called external separation, illustrated in [Fig. 7].

[0049] In [Fig. 8], an embodiment is shown in which the primer trench 12 extends into the third part 22 of the substrate 4, opening into the external trench 10.

[0050] In [Fig. 11], the starter trench 12 is partially formed in the second and third parts 21, 22 of substrate 4.

[0051] In [Fig. 12], the primer trench 12 extends in the second part of the substrate from the main zone 13 towards a secondary zone 14 of the internal trench 11, the primer trench 12 furthermore opening into the secondary zone 14.

[0052] According to another embodiment, shown in [Fig. 10], the initiator trench 12 is partially formed in the third part 22 of the substrate 4 by opening into the external trench 10 and the internal separation SI comprises a generation of a crack which propagates along the internal trench 11.

[0053] In Figures 15 to 17, an embodiment of the method is shown in which the primer trench 12 extends in the second and third parts 21, 22 of the substrate from a first zone 15 of the external trench 10 to a second zone 16 of the external trench 10, the primer trench 12 also opening into the first and second zones 15, 16.

[0054] Furthermore, the internal separation SI comprises a mechanical separation of the third part 22 of the substrate 4 into at least two distinct portions 23, 24 of the substrate 4 so as to obtain at least two photovoltaic cell elements 2, 3 from respectively said at least two distinct portions 23, 24 of the substrate 4.

[0055] The method may further comprise a connection S3 between at least two distinct portions 23, 24 of the substrate 4 to provide the same photovoltaic cell element 1.

[0056] In [Fig. 7], a so-called external separation S2 is shown, comprising a mechanical separation of the first part 20 with the third part 22. Generally, the external separation S2 comprises a generation of a crack which propagates at least along the external trench 10 and causes the physical separation of the first part 20 with the third part 22. The external separation S2 is carried out after the generation of the external trench 11. Preferably, the external separation S2 is carried out before the generation of the initiator trench 12. In order to facilitate the physical separation of the first part 20 with the third part 22, the method may comprise, before the external separation S2, a generation of an initial trench 17 on the first surface 5 of the substrate 4, in the first part 20 of the substrate 4 and opening into the external trench 11, as illustrated in FIGS. 3 and 18.The initial trench 17 provides a local fracture initiation to facilitate the propagation of the crack along the initial trench 17. The initial trench 17 therefore facilitates the physical separation of the first portion 20 of substrate 4, for example to obtain a sample comprising a substrate 4, several internal trenches 11 and several external trenches 10, as illustrated in [Fig. 4]. The generation of the initial trench 17 can be carried out before, or after, the generation of the internal trench 11. Preferably, the generation of the internal trench 11 is carried out after the separation. external S2. In fact, this limits the propagation of untimely cracks and facilitates internal separation SI.

[0057] In [Fig. 5], an embodiment is shown, in which the method comprises a generation of additional trenches 60 to facilitate the separation of the substrate 4 into several devices, each device comprising at least a third part 22.

[0058] Preferably, the generation of the seed trench 12 is carried out during the step of obtaining a sample, as illustrated in [Fig. 4], or during the step of generating additional trenches 60, illustrated in [Fig. 5].

[0059] Figures 13 and 14 also show other embodiments, in which the method comprises, after providing the substrate 4 and before generating the initiator trench 12, generating an additional trench 18 on the surface 5 of the substrate 4 and in the second part 21 of the substrate 4 to form an additional contour delimiting a fourth part 25 of the substrate 4 inside the additional contour, and mechanical separation S4 of the fourth part 25 with the second part 21. Thus, during the internal separation S1, the crack can propagate inside the free space left after the removal of the fourth part 25. The formation of untimely cracks within the third part 22 is further prevented. Preferably, the initiator trench 12 opens into the internal trench 11 and into the additional trench 18, as illustrated in [Fig. 14].This encourages the propagation of the crack in the free space which does not correspond to an area of ​​interest for manufacturing a photovoltaic cell element 1 to 3.

[0060] The method for manufacturing a photovoltaic cell element 1 to 3 makes it possible to manufacture an element 1 to 3 comprising a photovoltaic cell substrate 4 configured to generate electrons upon receipt of light radiation, an external contour and an internal contour delimiting the substrate 4, such that the element 1 to 3 is devoid of material outside the external contour and inside the internal contour and that the substrate comprises a starter trench 12 formed at least partially on a surface 5 of the substrate.

[0061] Such an element 1 to 3 makes it possible to provide a method for manufacturing a photovoltaic cell 30. The method for manufacturing the cell 30 comprises manufacturing at least one photovoltaic cell element 1 to 3 and metallization, after providing the substrate 4, the metallization comprising forming a first electrically conductive structure on a first surface 5 of the substrate 4 and a second electrically conductive structure on a second surface 50 of the substrate 4, opposite the first surface 5. The first and second electrically conductive structures are not shown for the purpose of simplification. The metallization can be carried out before generating the internal 11 and external 10 trenches, or after the manufacture of the photovoltaic cell element 1 to 3. For example, the first electrically conductive structure may be made from silver, printed on the first surface 5, by screen printing. The second electrically conductive structure may be a transparent conductive layer on the second surface 50.

[0062] The means which have just been described make it possible to manufacture photovoltaic cell elements having unconventional shapes, in particular hollowed out. Such elements are particularly suitable for manufacturing photovoltaic cells, in particular with very high efficiencies, intended to be integrated into small devices, such as smart mobile phones, etc.

Claims

Claims

1. A method of manufacturing at least one photovoltaic cell element, comprising: - providing a photovoltaic cell substrate (4) configured to generate electrons upon receipt of light radiation; and - generating a so-called external trench (10) on a surface (5) of the substrate (4) to form a closed external contour delimiting a first portion (20) of the substrate (4) outside the external contour; characterized in that it comprises: - generating a so-called internal trench (11) on the surface (5) of the substrate (4) to form a closed internal contour delimiting a second portion (21) of the substrate (4) inside the internal contour and a third portion (22) of the substrate (4) between the external and internal contours;- a generation of a seed trench (12) on the surface (5) of the substrate (4), the seed trench (12) being formed at least partially in at least one part of the substrate (4) among the second and third parts (21, 22) of the substrate (4) to facilitate a mechanical separation of the second and third parts (21, 22); and - a so-called internal separation (SI) comprising a mechanical separation resulting in a physical separation of the second part (21) with the third part (22) so as to obtain at least one photovoltaic cell element from the third part (22) of the substrate (4).;

2. Method according to claim 1, in which the initiator trench (12) opens into a main zone (13) of the internal trench (11) and the internal separation (SI) comprises a generation of a crack which propagates along the initiator trench (12) and along the internal trench (11).

3. A method according to claim 2, wherein the primer trench (12) extends into the third portion (22) of the substrate (4) opening into the external trench (10).

4. A method according to claim 2, wherein the primer trench (12) is formed partially in the second and third portions (21, 22) of the substrate (4).

5. Method according to claim 2, in which the primer trench (12) extends in the second part (21) of the substrate (4) from the main zone (13) towards a secondary zone (14) of the internal trench (11), the primer trench (12) furthermore opening into the secondary zone (14).

6. A method according to claim 1, wherein the primer trench (12) extends into the second and third (21, 22) portions of the substrate (4) from a first area (15) of the outer trench (10) to a second area (16) of the outer trench (10), the primer trench (12) further opening into the first and second areas (15, 16).

7. Method according to the preceding claim, in which the internal separation (SI) comprises a mechanical separation resulting in a physical separation of the third part (22) of the substrate (4) into at least two distinct portions (23, 24) of the substrate (4) so ​​as to obtain at least two photovoltaic cell elements from respectively said at least two distinct portions (23, 24) of the substrate (4).

8. Method according to the preceding claim, comprising a connection (S3) between at least two distinct portions (23, 24) of the substrate (4) to provide the same photovoltaic cell element.

9. Method according to claim 1, in which the initiator trench (12) is partially formed in the third part (22) of the substrate (4) by opening into the external trench (10) and the internal separation (SI) comprises a generation of a crack which propagates along the internal trench (11).

10. A method according to any preceding claim, wherein at least one of the outer (10), inner (11) and primer (12) trenches is a trench made in a non-through manner within the substrate (4).

11. A method according to any preceding claim, wherein generating the seed trench (12) creates a partly straight seed trench (12).

12. Method according to one of the preceding claims, comprising, after the generation of the external trench (10) and before the generation of the starter trench (12), a so-called external separation (S2), comprising a mechanical separation causing a physical separation of the first part (20) with the third part (22).

13. Method according to one of claims 1 to 11, comprising, after the internal separation (SI), a so-called external separation (S2), comprising a mechanical separation resulting in a physical separation of the first part (20) with the third part (22).

14. Method according to claim 12 or 13, comprising, before the external separation (S2), a generation of an initial trench (17) on the surface (5) of the substrate (4), in the first part (20) of the substrate (4) and opening into the external trench (10).

15. A method according to any preceding claim, comprising, after providing the substrate (4) and before the internal separation (SI), generating an additional trench (18) on the surface (5) of the substrate (4) and in the second portion (21) of the substrate (4) to form an additional contour delimiting a fourth portion (25) of the substrate (4) within the additional contour, and mechanical separation resulting in physical separation of the fourth portion (25) from the second portion (22).

16. Method according to the preceding claim, in which the starter trench (12) opens into the internal trench (11) and into the additional trench (18).

17. A method of manufacturing a photovoltaic cell, comprising manufacturing at least one photovoltaic cell element according to one of claims 1 to 16 and at least one metallization, before or after the internal separation (SI), the metallization comprising forming a first electrically conductive structure on a first surface (5) of the substrate (4) and a second electrically conductive structure on a second surface (50) of the substrate (4), opposite the first surface (5).

18. Photovoltaic cell element, comprising: a photovoltaic cell substrate (4) configured to generate electrons upon receipt of light radiation, characterized in that the element comprises an external contour and an internal contour delimiting a surface (5) of the substrate (4), in that the element is devoid of material outside the external contour and inside the internal contour and in that the substrate (4) comprises a starter trench (12) formed at least partially on the surface (5) of the substrate (4).

19. Photovoltaic cell, comprising a photocell element voltaic according to claim 18, and a first electrically conductive structure located on a first surface (5) of the substrate (4) and a second electrically conductive structure located on a second surface (50) of the substrate (4), opposite the first surface (5).

Images