System and method for manufacturing a photovoltaic cell element

Abstract

The invention relates to a system for manufacturing a photovoltaic cell element (2, 3), the element (2, 3) comprising a substrate (4) configured to generate electrons upon receipt of light radiation, the substrate (4) comprising a main surface (5), a secondary surface (6) and a cut (7) in the main surface (5) for forming an inner contour delimiting a part (8) to be hollowed out and a part (9) to be preserved, the system comprising a first piece (10) provided with a first hole (13), a second piece provided with a second hole (14), the first and second pieces being configured to co-operate such that the element (2, 3) is in contact with the first and second pieces (10, 11), and a stamper (12) capable of being inserted into at least one hole so as to be brought into contact with the part (8) to be hollowed out in order to separate it from the part (9) to be preserved.

Description

[0001] “system and method for manufacturing a photovoltaic cell element”

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The present invention relates to the manufacture of a photovoltaic cell element, and more particularly to the production of photovoltaic cells having unconventional geometric shapes such as shapes having a hollowed-out internal part, for example rings.

[0004] STATE OF THE ART

[0005] Generally speaking, 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 for the preferred collection of one type of carrier (electrons or holes). The substrate primarily used comprises silicon.

[0006] Currently, there are industrial solutions for cutting photovoltaic cells. Typically, cell cutting is used to obtain cells of reduced size and variable shape for various uses. For example, small cells can be used to integrate them into electronic devices such as calculators or smart phones. The most commonly used solution is irradiation with a laser beam, followed by a mechanical cleavage step. Irradiation involves firing a laser at a photovoltaic cell to form a trench in the substrate to facilitate the separation of the cell into two elements. Cleaving involves physically and manually separating two parts of the same cell to obtain two distinct, reduced-size photovoltaic cell elements.But cleavage is a delicate operation, because the silicon substrate is fragile, i.e. brittle. The cleavage step can therefore cause the cell to break into numerous elements with unwanted random shapes. In addition, irradiation emits strong heat at the point of impact, both on the surface and deep within. The heat emission, which can lead to silicon melting, significantly degrades cell performance.

[0007] For example, patent documents CN202058753, JP2022006823, US2019 / 163137, EP1708282, WO2019 / 076468, JP2005236017 and WO2022 / 074651 can be cited.

[0008] To limit this significant degradation, the laser power must be reduced and in this case it no longer allows efficient cleavage. Indeed, with reduced laser power, cleavage becomes difficult and random, which causes high breakage rates.

[0009] There is therefore a general need to produce photovoltaic cells in unconventional shapes. Conventional photovoltaic cell shapes are generally discs or squares, with protruding or rounded edges.

[0010] Photovoltaic cells may also be used for various devices, such as roller shutters or connected objects, particularly for small devices, such as calculators, etc.

[0011] An object of the invention is to provide means for providing a photovoltaic cell element having various shapes with satisfactory performance.

[0012] Another object is to provide means of manufacturing photovoltaic cell elements suitable for limiting the breakage rate.

[0013] Another object is to provide means for providing a photovoltaic cell element suitable for integration within a small-sized device.

[0014] SUMMARY OF THE INVENTION

[0015] To achieve this objective, a system is provided for manufacturing a photovoltaic cell element, the element comprising a photovoltaic cell substrate configured to generate electrons upon receipt of light radiation, the substrate comprising a main surface and a secondary surface opposite the main surface as well as a trench on the main surface to form an internal contour delimiting a portion to be hollowed out inside the internal contour and a portion to be retained outside the internal contour.

[0016] The system including:

[0017] - a first part provided with a first orifice,

[0018] - a second part provided with a second orifice, the first and second parts being configured to cooperate in such a way that one of the first and second parts is in contact with the main surface of the substrate and the other of the first and second parts is in contact with the secondary surface of the substrate, and

[0019] - a stamper capable of being introduced into at least one orifice among the first and second orifices so as to be brought into contact with the part to be hollowed out to separate it from the part to be preserved.

[0020] It turns out that this system allows for a completely unexpected reduction in the breakage rate, particularly at the delicate stage of hollowing out the central part of the photovoltaic cell element. Such a system is particularly suitable for manufacturing hollowed-out photovoltaic cell elements, i.e. without material in their center. The system allows separation of the part to be hollowed out without breaking the part to be preserved.

[0021] According to another aspect, there is provided an assembly, comprising a photovoltaic cell element provided with a photovoltaic cell substrate configured to generate electrons upon receipt of light radiation, the substrate comprising a main surface and a secondary surface opposite the main surface as well as a trench on the main surface to form an internal contour delimiting a portion to be hollowed out inside the internal contour and a portion to be kept outside the internal contour, the assembly comprising a system as defined above.

[0022] According to another aspect, there is provided a method of manufacturing a photovoltaic cell element using a system as defined above, the method comprising an initialization comprising a cooperation of the first and second parts of the system so that one of the first and second parts is in contact with the main surface of the substrate of the photovoltaic cell element and the other of the first and second parts is in contact with the secondary surface of the substrate, and a stamping comprising an introduction of the stamper of the system into at least one orifice among the first and second orifices of the first and second parts so as to put the stamper in contact with the part of the substrate to be hollowed out to separate it from the part of the substrate to be preserved.

[0023] BRIEF DESCRIPTION OF THE FIGURES

[0024] 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: Figure 1, schematically illustrates an exploded perspective view of an embodiment of a system for manufacturing a photovoltaic cell element; Figure 2, schematically illustrates a top view of an embodiment of a photovoltaic cell element; Figures 3 to 5, schematically illustrate the main steps of another embodiment of a method for manufacturing a photovoltaic cell element; Figures 6 and 7, schematically illustrate sectional views of other embodiments of a system for manufacturing a photovoltaic cell element;Figures 8 to 11 schematically illustrate the main steps of another embodiment of a method for manufacturing a photovoltaic cell element; Figure 12 schematically illustrates other embodiments of a photovoltaic cell element.;

[0025] The drawings are given by way of example 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 to the scale of practical applications.

[0026] DETAILED DESCRIPTION OF THE INVENTION

[0027] Before commencing a detailed review of embodiments of the invention, optional features which may optionally be used in combination or alternatively are set out below.

[0028] - According to one example, an imprint of the element is formed on one of the first and second parts.

[0029] - According to one example, one of the first and second parts is configured to be removably mounted on the other of the first and second parts.

[0030] - According to one example, one of the first and second parts is configured to be screwed onto the other of the first and second parts.

[0031] - According to one example, one of the first and second parts is a single piece.

[0032] - According to one example, the system comprises an intermediate part shaped to be brought into contact with one of the main and secondary surfaces, the intermediate part being mounted with a degree of freedom, or fixedly, on one of the first and second parts.

[0033] - According to one example, one of the first and second parts is shaped to form a guide configured to cooperate with the stamper so as to guide the stamper during its introduction into said at least one orifice.

[0034] - According to one example, the first and second parts grip the substrate during stamping.

[0035] - According to one example, the stamping comprises placing the main surface of the substrate opposite the stamper.

[0036] - According to one example, the initialization comprises bringing the main surface of the substrate into contact with the first part and in which the first part carries the substrate.

[0037] - According to one example, the initialization comprises removably mounting one of the first and second parts onto the other of the first and second parts.

[0038] - According to one example, the method comprises, before initialization, a step of generating the trench on the main surface of the substrate.

[0039] In Figures 1 and 3 to 7, a system 1 for manufacturing a photovoltaic cell element 2, 3 is shown. In particular, in Figures 3 to 5, the main steps of a method for manufacturing a photovoltaic cell element 2, 3 are also shown.

[0040] A cell element 2, 3 is intended to manufacture a photovoltaic cell.

[0041] The element 2, 3 comprises a photovoltaic cell substrate 4. The substrate 4 is configured to generate electrons upon receipt of light radiation. The substrate 4 comprises a main surface 5 and a secondary surface 6 opposite the main surface 5. The substrate 4 further comprises a trench 7 on the main surface 5 to form an internal contour delimiting a portion to be hollowed out 8 inside the internal contour and a portion to be retained 9 outside the internal contour.

[0042] Generally, a cell element 2, 3 is said to be functional, that is to say that the cell element preferably comprises a substrate 4 based on crystalline silicon. Preferably, the cell element 2, 3 is of the heterojunction type, that is to say comprising a layer of a crystalline substrate and at least one layer of hydrogenated amorphous silicon in contact with the layer of crystalline substrate. More particularly, the cell element 2, 3 is a functional cell comprising a hollowed-out portion 8. The cell element 2, 3 may have different shapes, for example an annular shape, as illustrated in FIG. 2.

[0043] Generally, the cell element 2, 3 is obtained by cutting from a conventional cell, as illustrated in Figure 8. The conventional cell before cutting comprises metallization patterns, for example made by screen printing. The patterns can be adapted to suit the desired final annular functional cells. Thus, the final functional cell 3 is based on a substrate 4, preferably made of crystalline silicon, and its main 5 and secondary 6 surfaces are provided with a metallization pattern, for example based on silver.

[0044] Generally, the trench 7 is made using a laser. Preferably, the trench 7 is made in a non-through manner within the substrate 4.

[0045] The system 1 comprises first and second parts 10, 11, and a stamper 12.

[0046] The first part 10 is provided with a first orifice 13.

[0047] The second part 11 is provided with a second orifice 14.

[0048] In particular, the first and second parts 10, 11 are configured to cooperate in such a way that one of the first and second parts 10, 11 is in contact with the main surface 5 of the substrate 4 and the other of the first and second parts 10, 11 is in contact with the secondary surface 6 of the substrate 4.

[0049] Furthermore, the stamper 12 is capable of being introduced into at least one orifice 13, 14 among the first and second orifices so as to be brought into contact with the part to be hollowed out 8 to separate it from the part to be preserved 9. One of the first and second orifices 13, 14 intended to receive the stamper 12 has a section greater than or equal to the section of the body of the stamper 12. Furthermore, the other of the first and second orifices 13, 14 has a section greater than or equal to the section of the part to be hollowed out 8 so that the part to be hollowed out 8 can be housed, after separation, in said orifice. Thus, the other of the first and second orifices 13, 14 has a section configured so as not to block the part to be hollowed out 8 during stamping. Preferably, the orifice 13, 14 intended to receive the part to be hollowed out 8 has a cylindrical or conical shape widening towards the base of the part.One of the first and second orifices 13, 14 is preferably through, so as to allow the introduction of the stamper 12 so that it comes into contact with the element 2, 3, and more particularly with the part to be hollowed out 8 of the element 2, 3. The other of the first and second orifices 13, 14 may be through or blind. In particular, the other of the first and second orifices 13, 14 has a depth Pg which is greater than or equal to the thickness of the element 2, 3, so as to receive the hollowed out part 8 when it is separated from the part to be preserved. After the physical separation of the part to be hollowed out 8, the part to be preserved 9 remains in contact with the first and second parts 10, 11. The first and second parts 10, 11 are then separated to obtain the hollowed-out element 3, as illustrated in FIG. 2, i.e. the element 2, 3 devoid of material in its central part.

[0050] Thus, an element 2, 3 is obtained which may have an unconventional geometric shape, such as a round, elliptical, triangular, ring, hexagon, etc., as illustrated in Figure 12. 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 2, 3 can easily be obtained. For example, the element 3 is of a round geometric shape, with a hollowed-out portion 8 which is also round, so as to form a ring, as illustrated in Figure 2.

[0051] The system 1 and the photovoltaic cell element 2, 3 form an assembly 100.

[0052] Generally, one of the first and second parts 10, 11 receives the element 2, 3 and is called the support part. The other of the first and second parts 10, 11 comes into contact with the element 2, 3 and is called the flange. In the example illustrated in Figure 1, the first part 10 corresponds to the support part and the second part 11 corresponds to the flange. In particular, the flange is shaped so as not to crush the element 2, 3 when the flange is in contact with the element 2, 3. For example, a mechanical stop, with or without locking, can be provided on the support part against which the flange comes into contact so as to be in contact with the element 2, 3 without crushing it. Alternatively, positioning of the flange can be provided using a robot which precisely adjusts the positioning of the flange relative to the element 2, 3.According to another embodiment, illustrated in Figure 7, the system 1 may comprise an elastic member 60, for example a spring, preferably a compression spring, for applying a force to the flange so as to ensure contact between the flange and the element 2, 3. The elastic member 60 may be mounted on the flange and configured to cooperate with the stamper 12, so that when the stamper 12 is introduced into the orifice of the flange, the stamper 12 applies a force to the elastic member 60 which transmits it to the flange. Alternatively, the elastic member 60 may be mounted on the stamper 12.

[0053] Advantageously, the flange has a face intended to be in contact with one of the main and secondary surfaces 5, 6 of the element 2, 3, configured to be parallel to said surface 5, 6 of the element 2, 3, when the flange is in contact with the element 2, 3.

[0054] Advantageously, and as illustrated in Figure 3, an imprint 20 of the element 2, 3 is formed on one of the first and second parts 10, 11. In the example illustrated in Figure 1, the imprint 20 is formed on the first part 10, i.e. the support part. The part 10, 11 provided with the imprint 20 is also called the guide support part. The guide support part makes it possible to receive and maintain the element 2, 3 in position. Furthermore, the imprint 20 makes it possible to center the element 2, 3 relative to the guide support part, and more particularly relative to the longitudinal axis A which passes through the center of the element 2, 3. The imprint 20 has a shape which approaches the outer edge of the element 2, 3. Preferably, the imprint 20 has a shape complementary to that of the element 2, 3 so as to serve as a housing for it. Advantageously, the imprint 20 is shaped to be in contact with the outer edge of the element 2, 3.For example, the depth Pf of the imprint 20 is less than or equal to the thickness Ec of the element 2, 3.

[0055] For example, one of the first and second parts 10, 11 is configured to be removably mounted on the other of the first and second parts

[0056] 10, 11. According to one embodiment, one of the first and second parts 10, 11 is configured to be screwed onto the other of the first and second parts 10,

[0057] 11. For example, as shown in Figure 3, the flange is configured to be screwed onto the support part. That is to say that one of the first and second parts 10, 11 may comprise an internal screw thread 40 intended to cooperate with a complementary external screw thread 41 formed on the other of the first and second parts 10, 11. Alternatively, one of the first and second parts 10, 11 may comprise a longitudinal internal groove extending parallel to the longitudinal axis A, intended to cooperate with an external longitudinal lug formed on the other of the first and second parts 10, 11. Thus, the screw thread 40, or the longitudinal internal groove of one of the first and second parts 10, 11 makes it possible to guide said part 10, 11 so that the face of said part is parallel to the surface 5, 6 of the element 2, 3, in contact of said part 10, 11 with the element 2, 3.The screw thread 40 or the longitudinal internal groove makes it possible to maintain the element 2, 3 in contact with the first and second parts 10, 11. Preferably, the first and second parts 10, 11 are configured so that when they are in contact with the element 2, 3, the element 2, 3 is stationary relative to the first and second parts 10, 11.

[0058] Preferably, one of the first and second parts 10, 11 is a single-piece part. A single-piece part is understood to mean a part consisting of a single part. Alternatively, the system comprises an intermediate part 30 shaped to be placed in contact with one of the main 5 and secondary 6 surfaces. The intermediate part 30 can be mounted on one of the first and second parts 10, 11 with a degree of freedom, for example with a translation along an axis parallel to the longitudinal axis A. Alternatively, the intermediate part 30 can be mounted in a fixed manner, on one of the first and second parts 10, 11. The intermediate part 30 makes it possible to wedge the element 2 to keep it immobile in order to further promote the separation of the part to be hollowed out 8 from the part to be preserved 9. For example, the intermediate part 30 can be made of elastomer.

[0059] Advantageously, one of the first and second parts 10, 11 is shaped to form a guide configured to cooperate with the stamper 12 so as to guide the stamper 12 during its introduction into at least one orifice 13, 14 among the first and second orifices. In the example illustrated in FIG. 3, the support part is configured to cooperate with the stamper 12, and also with the flange. For example, the guide may be a screw thread or a longitudinal groove. One of the first and second parts 10, 11 may comprise an additional internal screw thread 50 intended to cooperate with a complementary external screw thread 51 formed on the stamper 12. Alternatively, one of the first and second parts 10, 11 may comprise an additional internal longitudinal groove extending parallel to the longitudinal axis A, intended to cooperate with an external longitudinal lug formed on the stamper 12.The guide makes it possible to center the stamper 12 relative to the element 2, 3. The guide formed on one of the first and second parts 10, 11 makes it possible to gradually approach the stamper 12 towards the element 2, 3. Thus, the guide makes it possible to press the part to be hollowed out 8 evenly and limits the breakage rates. The stamper 12 has a body comprising a base 70, a support head 71 and a cylindrical trunk 72 connecting the support head 71 to the base 70. Preferably, the support head 71 has a section having a shape similar to that of the portion to be hollowed out 8 of the element 2, 3. For example, as illustrated in FIGS. 4 and 5, during the stamping step, the support head 71 comes to bear against the portion to be hollowed out 8 which, thanks to the trench 7 generated on the main surface 5, detaches from the portion of the substrate to be preserved 9. In particular, the method for manufacturing a photovoltaic cell element 2, 3 uses the manufacturing system 1 as defined above.

[0060] In particular, the method comprises initialization and stamping. The initialization makes it possible to position the element 2, 3 relative to the first and second parts 10, 11 so as to facilitate the removal of the part to be hollowed out 8. The stamping makes it possible to physically separate the part to be hollowed out 8 from the part to be retained 9. More particularly, the initialization comprises bringing the first and second parts 10, 11 of the system into cooperation, so that one of the first and second parts is in contact with the main surface of the substrate of the photovoltaic cell element and the other of the first and second parts is in contact with the secondary surface of the substrate. For example, bringing the surfaces 5, 6 into contact with the first and second parts 10, 11 can be carried out simultaneously.Alternatively, the initialization involves bringing the main surface of the substrate into contact with the first part and wherein the first part carries the substrate. In other words, the surface is in contact, then the part is moved relative to the other so that the opposite surface is in contact with the moved part.

[0061] The stamping comprises an introduction of the stamper of the system into at least one orifice among the first and second orifices of the first and second parts so as to bring the stamper into contact with the part of the substrate to be hollowed out to separate it from the part of the substrate to be preserved. The first and second parts grip the substrate 4 of the element 2, 3 during the stamping. The stamping may comprise a placement of the main surface of the substrate opposite the stamper.

[0062] The initialization may include removably mounting one of the first and second parts onto the other of the first and second parts.

[0063] Advantageously, the manufacturing method comprises, before initialization, a supply of a photovoltaic cell element 2, called initial element. By initial element, we mean an element 2, 3 in which the substrate 4 comprises the part to be hollowed out 8 and the part to be kept 9. In Figures 8 to 10, another embodiment of the manufacturing method has been shown. According to this other embodiment, the method comprises, before initialization, a step of generating the trench 7 on the main surface 5 of the substrate 4. More particularly, in Figure 8, a functional photovoltaic cell has been shown. In Figure 9, several trenches 7 have been produced on the main surface 5 of the substrate 4 in order to obtain several photovoltaic cell elements 2. In particular, several additional trenches 110, called external trenches, are produced, surrounding the trenches 7. The additional external trenches 110 are preferably produced by laser.In other words, each trench 7 is made inside an additional external trench 110. The additional external trenches 110 make it possible to separate the elements 2 of the photovoltaic cell, for example by mechanical cleavage. Several cell elements 2 are thus obtained, as illustrated in Figures 10 and 11. Depending on the shapes of the additional external trenches 110, photovoltaic cell elements 2 are obtained which may have different shapes. For example, in Figure 10, an element 2 is shown having a round shape. In Figure 11, three elements 2 are shown having respectively square, rectangular and triangular shapes. In Figure 12, three elements 3 are shown obtained from respectively the three elements 2 illustrated in Figure 11, after separation, for each of the three elements, of the part to be hollowed out 8 with the part to be kept 9.

Claims

DEMANDS 1. System for manufacturing a photovoltaic cell element (2, 3), the element (2, 3) comprising a photovoltaic cell substrate (4) configured to generate electrons upon receipt of light radiation, the substrate (4) comprising a main surface (5) and a secondary surface (6) opposite the main surface (5) and a trench (7) on the main surface (5) to form an internal contour delimiting a portion to be hollowed out (8) inside the internal contour and a portion to be retained (9) outside the internal contour, the system comprising: • a first part (10) provided with a first opening (13), • a second part (11) provided with a second orifice (14), the first and second parts (10, 11) being configured to cooperate such that one of the first and second parts (10, 11) is in contact with the main surface (5) of the substrate (4) and the other of the first and second parts (10, 11) is in contact with the secondary surface (6) of the substrate (4), and • a stamper (12) suitable for being introduced into at least one orifice (13, 14) among the first and second orifices (13, 14) so ​​as to be brought into contact with the part to be hollowed out (8) in order to separate it from the part to be retained (9).

2. System according to the preceding claim, wherein one of the first and second parts (10, 11) is configured to be removably mounted on the other of the first and second parts (10, 11).

3. System according to any one of the preceding claims, wherein one of the first and second parts (10, 11) is configured to be screwed onto the other of the first and second parts (10, 11).

4. System according to any one of the preceding claims, wherein one of the first and second parts (10, 11) is monobloc.

5. System according to any one of claims 1 to 3, comprising an intermediate piece (30) shaped to be in contact with one of the principal and secondary surfaces (5, 6), the intermediate piece (30) being mounted with one degree of freedom, or in a fixed manner, on one of the first and second pieces (10, 11).

6. A system according to any one of the preceding claims, wherein one of the first and second parts (10, 11) is shaped to form a guide (35) configured to cooperate with the stamper (12) so as to guide the stamper (12) during its introduction into said at least one orifice (13, 14).

7. System according to any one of the preceding claims, wherein an imprint (20) of the element (2, 3) is formed on one of the first and second parts (10, 11).

8. Assembly, comprising a photovoltaic cell element (2, 3) equipped with a photovoltaic cell substrate (4) configured to generate electrons upon receipt of light radiation, the substrate (4) comprising a main surface (5) and a secondary surface (6) opposite the main surface (5) and a trench (7) on the main surface (5) to form an internal contour delimiting a portion to be hollowed out (8) inside the internal contour and a portion to be retained (9) outside the internal contour, the assembly comprising a system according to any one of claims 1 to 7.

9. A method for manufacturing a photovoltaic cell element using a system according to any one of claims 1 to 7, the method comprising: • an initialization comprising a cooperation of the first and second parts (10, 11) of the system such that one of the first and second parts (10, 11) is in contact with the main surface (5) of the substrate (4) of the element (2, 3) of photovoltaic cell and that the other of the first and second parts (10, 11) is in contact with the secondary surface (6) of the substrate (4), • and a stamping comprising an introduction of the stamper (12) of the system into at least one orifice (13, 14) among the first and second orifices (13, 14) of the first and second parts (10, 11) so as to bring the stamper (12) into contact with the part of the substrate to be hollowed out (8) in order to separate it from the part of the substrate to be retained (9).

10. Method according to the preceding claim, wherein the first and second parts (10, 11) enclose the substrate (4) during stamping.

11. A method according to any one of claims 9 to 10, wherein the stamping comprises a placement of the principal surface (5) of the substrate opposite the stamper (12).

12. A method according to any one of claims 9 to 11, wherein the initialization comprises bringing the main surface (5) of the substrate (4) into contact with the first part (10) and wherein the first part (10) carries the substrate (4).

13. Method according to any one of claims 9 to 12, wherein the initialization comprises a removably mounting of one of the first and second parts (10, 11) onto the other of the first and second parts (10, 11).

14. A method according to any one of claims 9 to 13, comprising, prior to initialization, a step of generating the trench (7) on the main surface (5) of the substrate (4).

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