Method and device for applying an adhesive backing sheet to the rear face of a photovoltaic panel

Abstract

The invention relates to a method and device for applying an adhesive backing sheet to the rear face of a photovoltaic panel. The backing sheet is a critical element for the reliability of a photovoltaic panel. Made of thermoplastic materials, it ensures the sealing and insulation of the panel's electrical components. Being exposed to solar radiation during the day and humidity at night, it tends to crack and powder. After a few years, it loses its sealing properties, allowing moisture to penetrate the panel and causing electrical and thermal defects that can be irreversible. To repair this sealing, the new method consists of moving the panel (1) longitudinally between the surface of a drum (2) equipped with a new adhesive backing sheet (3) and a pressure roller (6) which simultaneously drives the panel (1) and applies the backing sheet (3).The surface of the drum (2) used is delimited by a first fixed notch (4) into which the front cross profile is inserted and a second notch (5) adjustable over an arc (dL), a function of the difference in length (L) of the panels, into which the rear cross profile is engaged. The method and device find their main application in the on-site repair of photovoltaic panels in power plants. Figure for the abstract: FIG 1.

Description

Title of the invention: Method and device for applying an adhesive backing sheet to the rear face of a photovoltaic panel

[0001] The present invention relates to a method and device for applying an adhesive backing sheet to the back face of a photovoltaic panel.

[0002] The backsheet is a critical element for the reliability of a photovoltaic panel. Made of thermoplastic materials, it ensures the sealing and insulation of the panel's electrical components. Being exposed to solar radiation during the day and humidity at night, it tends to degrade through decomposition and powdering of the material, and then to crack. After a few years, it loses its sealing and insulating properties, allowing moisture to penetrate the panel and causing electrical and thermal defects that can be irreversible.

[0003] Photovoltaic power plants can contain more than one million panels, which are normally designed to last 25 years. However, for reasons of cost and competitiveness, some panel manufacturers use substandard components, leading to premature degradation of panel performance. It is estimated that approximately 16% of the total number of panels used in power plants have cracked backing sheets and are at risk of irreversible defects in the short term. This mainly concerns backing sheets made of polyamide, but not exclusively.

[0004] Producers, not yet having the option of repairing these defective panels, are forced to dismantle them, take them to recycling centers, and install new ones. This has a cost for the energy producer, the community, and the environment.

[0005] There are some repair methods, however, but currently, probably for technical and economic reasons, none has become widespread.

[0006] Some use adhesive patches stuck onto the damaged parts. But in general, the cracks in the backing sheet extend over the entire surface of the panel.

[0007] Others use a partial or total coating of liquid silicone.

[0008] Others, such as the one proposed in patent EP4040509A1, propose covering the damaged backing sheet with a new sheet using a complex process involving a cutting table to first shape the new backing sheet, then a drum that is lowered and moved above the table to position the said shape by suction, and then raised to allow the panel to pass upside down onto the table, then be lowered back down to be applied and moved onto the bottom of the panel.

[0009] The repair method used also consists of covering the defective backing sheet with a new, high-quality adhesive backing sheet in order to restore a durable seal and a service life of 25 years. We will explain below why the technical problem is difficult, how it was solved, and we will appreciate the simplicity of the solutions found and their novel and inventive characteristics.

[0010] The technical problem to be solved presents several major difficulties.

[0011] The first difficulty is that the peripheral profiles of the rectangular frame, which provides rigidity to the panel, protrude both in depth and width relative to the flat rectangular shape of the panel to be treated. This makes it impossible to apply the backing sheet using a conventional application method. Indeed, the new adhesive backing sheet must be able to be applied right up to the inside of the profiles, most of which are U-shaped with a lower flange that obstructs the passage of the new backing sheet. It is clear that this problem is more difficult to solve than that of the initial application, which was carried out on a flat panel before the protruding frame profiles were installed and glued in place.

[0012] The second difficulty is that the application device must be adjustable to accommodate the extremely varied dimensions and arrangement of the panel components. Production panels are formed from an assembly of cells ranging in size from 156 x 156 mm (M1 type cells) to 166 x 166 mm (M6 type cells), and the number of these cells can vary from 60 (6 wide and 10 long) to 72 (6 wide and 12 long). The junction boxes used protrude from the panel's base and vary in size and arrangement. Finally, the aluminum profiles used differ in both height and width.

[0013] The new method of the invention consists of moving the panel longitudinally and in the right position on a drum equipped with an adhesive backing sheet installed between two transverse and adjustable notches, by means of a pressure roller which ensures both the drive of the panel by friction and the application of the backing sheet.

[0014] The transverse and adjustable notches on the surface of the drum are the solution to the salient nature of the transverse profiles and the different lengths of the panels to be processed.

[0015] The width of the drum must obviously be less than the internal width of the frame in order to pass between the longitudinal profiles, but it must also be greater than a certain value to solve the problem of the automatic insertion of the edges of the base sheet under each of the flanges of the longitudinal profiles. This The value is calculated based on the panel width and profile dimensions. If the drum's side face is too close to the profile flange, the backing sheet may wrinkle during insertion; if the drum's side face is too far away, the backing sheet will not automatically insert under the profile flange, requiring subsequent manual intervention.

[0016] The invention and its embodiment variants will be better understood upon view of the attached drawings:

[0017] Figure 1 shows a general view of the application process

[0018] Figure 2 represents the lateral insertion geometry of the margin

[0019] Figure 3 shows a general view of the application device

[0020] Figure 4 shows a view of the adjustment device for the second notch.

[0021] Figure 5 represents a variant of the second notch adjustment device.

[0022] Figure 6 shows the development of the base sheet on the ferrule.

[0023] Figure 7 shows a detailed view of the first notch fitted with the rail

[0024] Figure 8 shows a detailed view of the second notch fitted with the rail

[0025] Fig. 9 represents particular arrangements of the device, to improve its ergonomics.

[0026] Fig. 1 represents a general view of the method of the invention. The method consists of moving the panel (1) with its junction box and cables longitudinally and in the correct position on a drum (2) equipped with an adhesive backing sheet (3) installed between two transverse notches (4) and (5), by means of a pressure roller (6) which ensures both the movement of the panel (1) by friction and the application of the backing sheet (3).

[0027] The surface of the drum (2) used for the application is delimited by the first notch (4) which has a shape adapter depending on the front transverse profile inserted therein and by the second notch (5) which is adjustable over an arc (dL) depending on the difference in length (L) of the panels to be treated.

[0028] Figure 2 shows the lateral insertion geometry of the margin of width (m) under the pressing action of the drum (2). If we consider a panel (1) of width (Wp) and a drum (2) of width (Wt), it is clear from the figure that the insertion condition of the margin is that its width (m) be less than the oblique distance (d) between the edge of the drum and the end of the flange of the profile.

[0029] Let m < d, or m2 < a2 + p2 with (a) distance from the wing tip to the lateral face of the drum and (p) insertion depth of the drum relative to the wing face.

[0030] Or m = a +1 - r with (1) width of the wing and (r) margin retraction as a function of the thickness of the profile and its glue joint.

[0031] If we substitute (m) in the first expression with its value from the second expression, we find a < (p2 - (1 - r)2) / 2(1 - r), or Wt > Wp - 21 - 2a, or: Wt > Wp - 21 - (p2 - (1 - r)2) / (1 - r)

[0032] For example, for a panel of width Wp = 1000 mm and an aluminium profile of total height 40 mm with a flange (1) of 20 mm and a depth (p) of 30 mm, if the desired setback (r) is 15 mm, then Wt must be between 785 mm and 960 mm.

[0033] Fig. 3 represents a general view of the device for implementing the process, here represented as roller (6) raised awaiting the introduction of panel (1).

[0034] The chassis (7) carries two longitudinal slides (8) which are adjustable according to the width (Wp) of the panel (1).

[0035] It carries the drum (2) equipped with its two notches (4) and (5). The first notch (4) is fixed and equipped with a shape adapter for the precise insertion of the front cross profile of the panel (1). The second notch (5) is adjustable to receive, at the end of the application of the base sheet (3), the rear cross profile of the panel (1) of variable length (L).

[0036] The pressure roller (6) mounted on an articulated arm (9) is raised to allow the introduction of the front profile of the panel, lowered during the pressing of the base sheet (3) and then raised again at the end of the application to allow the rear profile to be released from its notch (5).

[0037] The chassis finally carries the spool (10) of base sheet (3) and its braking compass.

[0038] The longitudinal slides (8) are adjustable by means of lights (oblong holes) (adjustment) transverse struts whose stroke is half the difference between the maximum and minimum panel widths considered. In theory, for a drum of a given width (Wt), this difference cannot exceed the insertion conditions calculated above.

[0039] The height of the axis (11) of the drum (2) is adjustable by means of a screw whose stroke corresponds to the height difference (p) of the profiles used on the panels.

[0040] Preferably, a retractable indexing finger (12) is provided to immobilize the drum at the beginning, during or at the end of rotation, for example to facilitate the placement of the base sheet (3) or the insertion or removal of the panel profiles (1).

[0041] Preferably the necessary pressing force of approximately 1 daN per centimeter is ensured by the self-weight of the roller (6) and that of its articulation arm (9).

[0042] Preferably the drive force is provided by a crank and the grip by rubber bands mounted in grooves of the roller (6).

[0043] Figure 4 shows a view of the support device for the notch (5). The notch (5) is cut, according to the length (L) of the panel to be processed, on a sector The interchangeable sector (13) is mounted on the flange (14) of the drum (2). The drum (2) is equipped with a fixed ferrule section (15), while the interchangeable sector is equipped with an additional ferrule section (16) in which the junction box clearance (17) is formed, which is also specific to the panel model being processed. Therefore, there is one interchangeable sector (13) equipped with its additional ferrule (17) for each panel model.

[0044] Figure 5 shows a variant of the notch adjustment device (5). Here, the interchangeable sector (13) can be moved continuously along the slots machined on the flange (14) of the drum (2). The result is that there is only one sector for all panel designs. Figure 5 shows, as an example, a possible 90° travel of the sector, which corresponds to a displacement (dL) of 565 mm around the periphery of the drum with a diameter of 720 mm. This is more than the difference (dL) in length (L) between the 60-cell and 72-cell panels. To accommodate this movement, the junction between the supplementary ferrule (16) and the fixed ferrule (15), instead of being straight as in the device of Figure 4, can advantageously be V-shaped so as to ensure continuity during the passage of the pressure roller (6).

[0045] We have just seen the arrangements that allow a background sheet (3) to be applied to a panel (1) of variable dimensions. In what follows, we will discover the arrangements that allow the background sheet (3) to be formatted directly on the drum (2).

[0046] For this purpose, two rails (18) and (19) are temporarily mounted at the first notch (4) and the second notch (5) to position, place, and cut the backing sheet (3) to the length (L-2r) corresponding to the length (L) of the panel. A cutting stencil (20) corresponding to the clearance (17) required for the junction box is mounted on the additional ferrule (16).

[0047] Figure 6 shows the backing sheet (3) unfolded onto the drum ferrule (2), with the means used to shape it. The backing sheet (3) from the reel (10) is positioned on the ferrule by aligning the corners of its end with the stops (21) adjusted according to its width and centered on the rail (19). The backing sheet (3) is held in place by two double-sided adhesive patches (22) attached to the complementary ferrule (16). The cutout (17) for the junction box can then be made using a cutter along the interchangeable cutting template (20). The drum (2) is then rotated manually to continue positioning the backing sheet (3) up to the notch (4). The backing sheet (3) is held in place by two further double-sided adhesive patches (22). The rail (18) has a slot (23) intended to guide a cutter for cutting the background sheet (3).The methods described above made it possible to format the sheet of . melts directly onto the drum. Now, as is known, the protective film of the adhesive can be removed by hand.

[0048] Figure 7 shows a detailed view of the first notch (4) fitted with the rail (18) having the cutting slot (23) for the base sheet (3) shown cut to length (L-2r). The rail (18) can be temporarily mounted in the notch (4) by means of a ball locking device (24) integral with the rail (18). The shape adapter (25) described previously is also shown.

[0049] Figure 8 shows a detailed view of the second notch (5) equipped with the rail (19). Unlike the rail (18), it does not have a cutting groove but adjustable positioning stops (21). This eliminates a cutting operation. However, it is equipped with a hinge (25) and clamping device (26) to apply an upper cutting stencil (27) against the lower cutting stencil (20). The advantage is that the base sheet is held firmly so that it does not slip under the cutting force, and, above all, the movement of the cutter along the stencil can be visualized.

[0050] Fig. 9 represents particular arrangements of the device to improve its ergonomics. The first arrangement is that the chassis is completely open on the side where the operator (28) intervenes to facilitate the placement of the rails, to take the end (29) of the base sheet (3) stored on the reel (10), to adjust its end (29) at the level of the notch (5), to fix it at the level of the patches (22) and to cut the passage (17) of the junction box and finally to turn by hand the drum in order to place the base sheet (3) up to the level of the notch (4) and finally to cut the base sheet on the rail (18) temporarily mounted in the notch (4).

[0051] The second arrangement is to install a slack take-up device (30) to tension the backing sheet (3) during its cutting on the rail (18) and to automatically take up its end (29) after the cut. This arrangement prevents the end (29) of the backing sheet (3) from falling as shown in [Fig. 3], but from remaining at the operator's hand level during the processing of the next panel. The slack take-up device (30) is a simple weighted tube (31) guided at its ends on two vertical rods (32) by means of large holes. The advantage of this compliant assembly is that it allows precise positioning of the backing sheet (3) on the drum (2), even in the event of a lack of parallelism between the axes of the reel (10) and the drum (2) or a lack of cylindricity of the reel (10).

[0052] The method and device, which are the subject of the invention, find their main application in the on-site repair of photovoltaic panels in power plants. They can also be used in the application of adhesive sheets to flat panels that also have a frame formed by protruding profiles.

Claims

Demands

1. Method of applying an adhesive backing sheet (3) under a rectangular photovoltaic panel (1) of width (Wp) and length (L), comprising transverse and longitudinal peripheral profiles projecting in height (p) as in width (1), characterized in that the panel (1) is moved longitudinally and in the right place on a drum (2) equipped with an adhesive backing sheet (3) installed between two transverse notches (4) and (5), by means of a pressure roller (6) which ensures both the drive of the panel (1) by friction and the application of the backing sheet (3).

2. The method according to claim 1 characterized in that the first notch (4) comprises a shape adapter (25) that is a function of the front transverse profile inserted therein, and that the second notch (5) is adjustable over an arc (dL) that is a function of the difference in length L of the panels to be treated,

3. A method according to claim 1 and 2 in which the edge of the base sheet (3) is applied with a retraction (r) under the wing of the width profile (1) characterized in that the width (Wt) of the drum (2) is greater than the value Wp-21-(p2-(1-r)2) / (1-r) and less than the value Wp-21 in a known manner.

4. A device for implementing the method according to claims 1 to 3, characterized in that it comprises: - A frame (7) carrying two longitudinal slides (8) for receiving the panel. - A drum (2) equipped with a fixed notch (4) and an adjustable notch (5). - A pressure roller (6) mounted on an articulated arm (9). - And a support (10) for the reel on which the backing sheet (3) is stored.

5. Device according to claim 4 characterized in that the longitudinal slides (8) are adjustable by means of transverse slots whose maximum stroke is, for a drum (2) of given width (Wt), half the value (p2 - (1 - r)2) / (1 - r).

6. Device according to claim 4 characterized in that the axis (11) of the drum (2) is adjustable over a stroke corresponding to the height difference (p) of the profiles used on the panels.

7. Device according to claims 4 and 6 characterized in that the drum (2) can be indexed at the end of its stroke by a retractable indexing finger (12).

8. Device according to claim 4 characterized in that the notch (5) adjustable according to the length (L) of the panel is cut in a removable and interchangeable sector (13) mounted on the flange (14) of the drum (2).

9. Device according to claim 4 characterized in that the notch (5) adjustable according to the length (L) of the panel is cut in a sector (13) which can be moved continuously along the slots made in the flange (14) of the drum (2).

10. Device according to any one of claims 4, 8 and 9 characterized in that the drum (2) is equipped with a fixed ferrule portion (15) mounted on the flanges (14) of the drum and a complementary ferrule portion (16) mounted on the interchangeable or adjustable sector (13).

11. Device according to claim 10 characterized in that the additional ferrule portion (16) carries the clearance (17) necessary for the passage of the junction box and the panel cables.

12. Device according to claim 10 characterized in that the junction between the fixed ferrule (15) and the complementary ferrule (16) is V-shaped.

13. Device according to claim 4 characterized in that the pressing force is ensured by the self-weight of the roller (6) and that of its articulation arm (9).

14. Device according to claims 4 and 13 characterized in that the pressure roller (6) is driven in rotation by a crank.

15. Device according to any one of claims 4, 13 and 14 characterized in that the adhesion between the pressure roller (6) and the panel (1) is achieved by means of rubber bands mounted in grooves of the roller.

16. Device according to claim 4 characterized in that the fixed notch (4) can be temporarily equipped with a cutting rail (18) equipped with a cutting slot (23).

17. Device according to claim 4 characterized in that the adjustable notch (5) can be temporarily equipped with a positioning rail (19) equipped with adjustable stops (21).

18. 9 Device according to claim 17 characterized in that the positioning rail (19) is equipped with an articulated cutting stencil (27) clamping the base sheet (3) against the interchangeable cutting stencil (20) which carries the clearance (17) of the junction box.

19. Device according to claim 4 characterized in that a slack swallower (30) is disposed on the frame (7) between the reel (10) and the drum (2).

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