Backsheet and a method for insulating the back of a photovoltaic module

Abstract

Photovoltaic module with a multitude of photovoltaic cells and a front side defining a light-incidence side, and an opposite rear side defining a mounting side or connection side, with the following features: at least two connecting bands (50) which have a folding section (53) between an outer section (51) and an inner section (52); a backsheet formed on the back of the photovoltaic module and comprising the following: a foil substrate (110); at least one opening (120) with a connecting side (121) and a fixing side (122) in the film substrate (110) for passing through the at least two connecting strips (50); and at least one flap (130) which has a hinge connection on the connecting side (121) of the at least one opening (120) with the film substrate (110) and is movable between a closed position (I1) and an open position (I2), wherein the at least one opening (120) in the film substrate (110) is freely accessible in the open position (I2) for passing through the at least two connecting strips and in the closed position (I1) the flap (130) holds the at least two connecting strips (50) at the fixing side (122) of the opening (120), wherein the flap (130) of the back film is in the closed position (I1) to fix the outer section (51) to the fixing side (122), wherein the inner section (52) extends along a longitudinal extent of the back film to electrically contact various photovoltaic cells.

Description

[0001] The present invention relates to a photovoltaic module and a method for the rear insulation of a photovoltaic module and in particular to hinged openings in the backsheet for threading connecting strips. background

[0002] Photovoltaic modules with a large number of photovoltaic cells are typically electrically contacted from the back via junction boxes. Since high voltages can be generated in these modules (e.g., up to 1500 V), stringent insulation requirements must be ensured. For example, minimum distances to the side boundaries of the photovoltaic module or its frame must be maintained at the backside contacts. A backsheet is used for insulation on the back side, through which connection contacts are routed to electrically connect the photovoltaic cells. These connection contacts are, for example, designed as connection strips.

[0003] Aside from ensuring reliable insulation, it is often desirable to automate the application of the backsheet, including the insertion of the connecting strips. However, the automated threading of the connecting strips into the corresponding openings in the backsheet must guarantee that consistent insulation distances are maintained without significant tolerance variations.

[0004] Conventional backsheets currently use either slots or holes as openings for routing connecting strips. Both options have advantages and disadvantages. While slots allow for a precisely defined safety distance, the connecting strips can only be threaded manually. An automated process cannot accurately determine the position of the slots. Since holes offer a certain tolerance range, existing holes allow for automated threading of connecting strips. However, they do not ensure a fixed insulation distance to the exemplary edge area (e.g., an edge boundary) and require more material. For example, US 2013 / 0032199 A1 discloses such a retaining structure. Another backsheet retaining structure for connection contacts is described in US 2011 / 0083734 A1.Furthermore, DE 10 2004 012 885 A1, US 2013 / 074919A1 and US 2010 / 70229918A1 disclose further conventional contacting methods for photovoltaic modules.

[0005] Since reliable insulation must be ensured at voltages of up to 1500 volts or higher (to reliably prevent short circuits, sparking, or at least leakage currents), the back insulation of photovoltaic modules is currently often achieved by manually threading the connection straps through the backsheet (e.g., using the aforementioned slots). Alternatively, the junction boxes on the back are currently oversized to ensure compliance with edge and insulation clearances.

[0006] Furthermore, the back insulation, which can withstand voltages of 1500 volts, is often very thick compared to standard materials and therefore not very flexible. This makes manually threading the connecting straps through the slot openings difficult, which in turn often leads to damage to the cells in the connection area. For this reason as well, automated threading of the connecting straps would be desirable.

[0007] In order to further increase the efficiency of production while minimizing resource consumption, there is therefore a need for photovoltaic modules with a backsheet that enables automated threading of the connection strips and simultaneously ensures reliable rear insulation. Summary

[0008] The present invention solves the aforementioned technical problem by means of a photovoltaic module according to claim 1 and a method for back-side insulation of photovoltaic modules according to claim 9. The dependent claims relate to further advantageous embodiments of the subject matter of the independent claims.

[0009] The present invention relates to a photovoltaic module with a backsheet, wherein the photovoltaic module can be electrically contacted by means of at least two connection strips. The backsheet comprises a film substrate with at least one opening in the film substrate for leading out the at least two connection strips and a flap, wherein the opening(s) have a connection side and a fixing side. The flap has a hinge connection at the connection side of the opening with the film substrate and is movable between a closed position and an open position. In the open position, the opening in the film substrate is freely accessible for leading through the at least two connection strips, and in the closed position, the flap holds the at least two connection strips at the fixing side of the opening.The fixing side, for example, is long enough to secure at least two connection strips simultaneously. This reduces the number of required openings or allows them to be reduced to a minimum. Furthermore, the connection strips can make contact with different parts of the photovoltaic module.

[0010] Within the scope of the present invention, a flap is understood to be any element suitable for fixing the at least two connecting strips on the fixing side. In particular, the flap should be producible by any punching of the film substrate and thus be able to have any geometric shape that can be produced by punching. Fixing, within the scope of the present invention, does not necessarily mean that the at least two connecting strips are firmly attached to the film substrate, but merely that the at least two connecting strips cannot be moved in at least one direction due to the fixing, wherein one direction is the insulation direction in which a minimum distance is to be ensured (for example, to prevent sparking due to the potentially high voltages on the connecting strip).

[0011] The term "film substrate" as used in the present invention is to be interpreted broadly and is limited only by the fact that it is an (electrically) insulating material that exhibits a certain degree of flexibility, although this flexibility need not be very high. Therefore, in further embodiments, the hinge connection is formed by partial punching (e.g., as a perforated line) along the connection side. This is advantageous because the back insulation, which can withstand voltages of 1500 volts, is often very thick and correspondingly inflexible compared to standard materials. The partial punching or perforation facilitates the threading of the connecting strips through the openings.

[0012] The present invention solves the aforementioned technical problem by using openings with flaps which, in an open position, enable automated threading and, in a closed position, ensure the precisely defined insulation distance from an edge boundary for the connecting strips. A further advantage of exemplary embodiments is that automated manufacturing allows for cost reduction. Furthermore, forming the openings by means of a simple punch enables material-saving and rapid production.

[0013] Optionally, the fixing side of the opening can be located opposite the connecting side and have a straight section. However, the exact orientation of the fixing side relative to the connecting side is not necessarily prescribed by the present invention. In particular, it is possible for the fixing side and the connecting side to be perpendicular to each other. For example, the flap can be rectangular, defining a fixing side along its long side and connected to the film substrate along its short side to define the hinge connection. It is also possible for several flaps to be formed within an opening, which, in the open position, expose the opening and, in the closed position, provide a fixing for the at least two connecting strips.For example, the opening could be triangular, with two hinged triangular flaps exposing the triangular opening, and closing the two triangular flaps securing at least two connecting straps. Optionally, the opening can also be any n-gon, where the securing side and the connecting side can be, for example, adjacent or opposite sides of the n-gon. The flap(s) can, in particular, form a cover that at least partially closes the opening after the at least two connecting straps have been passed through. Therefore, in further embodiments, the shape of the at least one opening is one of the following: oval, trapezoidal, rectangular, triangular, or square, whereby, if several openings are present, not all openings need to have the same shape, but they can.

[0014] In further embodiments, the film substrate includes an edge boundary, and the fixing side is formed at a predetermined distance from the edge boundary. This predetermined distance can be selected to ensure sufficient insulation from the at least two protruding connection strips. The edge boundary does not necessarily refer to an edge of the film substrate but can also refer to an edge or frame of the photovoltaic module. For example, the frame can laterally overlap the photovoltaic module, so that the distance from the opening to the frame is less than the distance to the edge of the photovoltaic module (which may extend into the frame). Therefore, an edge boundary is understood to be any structure that can define a predetermined minimum distance.

[0015] The term "predetermined distance" should also be interpreted broadly. It need only be a minimum distance, but can also be larger than required for insulation. The fixing side and the edge boundary can, for example, be parallel, straight structures, allowing for a clear definition of the distance. However, if the fixing side and the edge boundary are not parallel or not straight, the predetermined distance can be defined as a minimum distance. Such a minimum distance can already ensure that no sparking can occur between the connecting strip and any structure at the edge boundary.

[0016] In further embodiments, the at least one opening comprises several openings and the fixing sides of the several openings are aligned parallel to the edge boundary.

[0017] The present invention also relates to a photovoltaic module with a backsheet formed on the rear side of the photovoltaic module. The rear side can be defined as the side facing the direction of light incidence (front side). Furthermore, the photovoltaic module comprises at least two connecting strips extending through the at least one opening in the film substrate. The flap of the backsheet is, for example, configured in a closed position to press the connecting strip against the fixing side.

[0018] A photovoltaic module is a photo-optical component that can be composed of numerous photovoltaic cells. Therefore, not only can one connection strip be inserted and secured through each opening, but multiple connection strips can be routed through simultaneously. These multiple connection strips can, for example, electrically connect different areas along the photovoltaic module in different directions. For instance, two strips can be routed through each opening, with the two strips on the back of the photovoltaic module extending in opposite directions. Optionally, the at least two connection strips on the side facing the photovoltaic module can be double-layered in certain sections.Furthermore, the opening can have a predetermined length in a direction parallel to the edge boundary, and the predetermined length is adapted to the shape of the at least two connecting strips.

[0019] In further embodiments, the photovoltaic module further comprises a rear lamination, wherein the lamination holds the flap in the closed position and thereby fixes the at least two connecting straps in the predetermined position.

[0020] The present invention also relates to a method for the rear insulation of the photovoltaic module. The method comprises providing at least one photovoltaic module, at least two connection strips, and one of the aforementioned backsheets. The method further comprises arranging the at least two connection strips such that the at least two connection strips extend through the at least one opening when the backsheet is applied to a rear side of the at least one photovoltaic cell, and closing the flap, thereby fixing the at least two connection strips to a side edge (fixing side) of the at least one opening.

[0021] In further embodiments, the method includes a further step of lamination, so that the flap remains fixed in the closed position. Brief description of the characters

[0022] The embodiments of the present invention are better understood from the following detailed description and the accompanying drawings of the different embodiments. Fig. Figure 1 shows a backsheet according to an embodiment of the present invention. Fig. Figure 2 shows an embodiment for a flap die-cutting of a backsheet film. Fig. Figures 3A and 3B show further details of the connection tape feed-through through an opening flap in a foil substrate. Fig. Figure 4 shows another embodiment for forming the opening. Fig. Figures 5A and 5B show an embodiment in which two connecting straps were passed through each opening. Fig. Figure 6 shows a flowchart for a method for the rear insulation of a photovoltaic module according to a further embodiment. Detailed description

[0023] Fig. Figure 1 shows a cross-sectional view through a backsheet according to an embodiment of a photovoltaic module, which can be electrically contacted by at least two connection strips (not shown). The backsheet comprises a film substrate 110 with at least one opening 120 in the film substrate 110 for leading out the connection strips, and a flap 130. The flap 130 is connected to the film substrate 110 at a connecting side 121 of the opening 120 via a hinge connection and is movable between a closed position I1 and an open position I2.

[0024] The hinge connection does not require any further structures – at least not as long as the film substrate 110 is sufficiently flexible to allow the flap 130 to open. Optionally, however, an incomplete die-cut, embossing, or other structure can be formed along the connection side 121 to facilitate opening and closing the flap 130. In the open position I2, the opening 120 in the film substrate 110 is freely accessible for the insertion of the connecting strips, and in the closed position I1, the flap 130 holds the connecting strips 50 against a fixing side 122 of the opening 120.

[0025] Fig. Figure 2 shows a further embodiment of the backsheet with an edge boundary 105, with a cross-sectional view shown on the right and a top view on the left. In the illustrated embodiment, the backsheet has a film substrate 110 with three openings 120a, 120b, 120c, each of which can be closed by a flap 130a, 130b, 130c. The openings 120 can be created, for example, by a die-cutting process in which the flaps 130 are not (completely) separated from the film substrate 110 at a connecting side 121a,b,c, but remain hinged to the film substrate 110 along the connecting side 121. The openings 120 are, for example, oval in shape, with one side opposite the connecting side 121 having a predefined distance d from the edge boundary 105.This distance d can be chosen such that sufficient insulation to an edge structure is ensured after the passage of connecting strips (not in the . Fig. 2 shown) is ensured.

[0026] Optionally, the openings 120 are equally spaced from each other and arranged along the edge boundary 105. They can have a longitudinal extension (e.g., along the edge boundary 105) that allows one or more connecting strips to be guided through the respective opening 120 and simultaneously fixed to the fixing side 122, so that they cannot be displaced perpendicular to the edge boundary 105 (in the top view).

[0027] In the cross-sectional view (right) it can be seen that the film substrate 110 has the flap 130 at the position of the opening 120, which is connected to the film substrate 110 in a way that is bendable or rotatable perpendicular to a surface extension of the film substrate 110, so that in the open position I2 the connecting strip 50 can be placed through the opening 120 and in the closed position I1 the connecting strip 50 is fixed to the fixing side 122.

[0028] The Fig. Figures 3A and 3B show further details of the passage of a connecting strip 50 (of at least two connecting strips) through the opening 120 with the flap 130. The connecting strip 50 comprises an outer section 51, an inner section 52, and a folded section 53, wherein the outer section protrudes from the insulated photovoltaic module in the installed state, and the inner section 52 is arranged between the backsheet and the photovoltaic module. The folded section 53 forms a connecting section between the outer section 51 and the inner section 52. In general, the connecting strip 50 is designed to be flexible (for example, as a rail). The details shown in the Fig. The opening shown in 3A, B is, for example, one of the openings 120a, 120b, 120c, as shown in the Fig. 2 are shown.

[0029] In the Fig. 3A shows the foil substrate 110 again in a cross-sectional view, the cross-section being placed through an opening 120 which is located in the Fig. 3A was closed by flap 130. Furthermore, in the exemplary embodiment of the Fig. 3A The connecting strap 50 has already been placed through the opening 120, which is fixed to the fixing side 122 after the flap 130 is closed. The connecting strap 50 can be attached to a side facing the photovoltaic module (at the bottom of the Fig. 3A) be folded multiple times (folding section 53) and extend parallel along a longitudinal dimension of the film substrate 110 (perpendicular to the plane of the drawing) Fig. 3A). Furthermore, when threading the connecting strip 50 through the foil substrate 110, the connecting strip 50 can be on the side facing away from the photovoltaic module (top in Fig. 3A) should initially also be bent parallel to the foil substrate 110 (see position A1). In this state, the flap 130 can be closed. Subsequently, the outer section 51 of the connecting strip 50 can be erected, i.e., moved from position A1 via positions A2 and A3 to the upright position A4.

[0030] The flap 130 should remain closed after the photovoltaic module has been insulated on the back using the backsheet. This can be achieved, for example, by lamination after the backsheet has been applied to the back of the photovoltaic module. The lamination can be carried out before the outer section 51 is erected (i.e., in position A1) or afterward (i.e., in position A4). After back-side lamination, flap 130 can no longer be opened.

[0031] The Fig. Figure 3B shows a top view of the foil substrate 110 (e.g., the top side of the Fig. 3A). In the top view, the exemplary oval shape of the opening 120 is visible, with the flap 130 remaining connected to the film substrate 110 along the unpunched side (connection side 121). As shown in the Fig. As shown in Figure 3B, the inner section 52 extends along a longitudinal dimension of the backsheet 110 to electrically contact various photovoltaic cells. Furthermore, the upright outer section 51 is fixed to the fixing side 122. Since the flap 130 remains closed after lamination and cannot be reopened, the connecting strip 50 is also fixed at the position of the fixing side 122 and cannot be moved. In addition, the fixing side 122 defines a fixed distance d to a side boundary 105, with virtually no tolerance, which provides a high degree of insulation reliability.

[0032] The Fig. Figure 4 shows an example of a connecting band 50 and another embodiment for the opening 120.

[0033] First, in the Fig. Figure 4(A) shows the connection strip 50 with the outer section 51, the inner section 52, and the fold 53. The outer section 51 serves for the external contacting of the connection strip 50, for example, by a junction box (not shown). The inner section 52 serves for the electrical contacting of the individual photovoltaic cells in the photovoltaic module (or of other connection structures to the photovoltaic cells). The fold 53 connects the inner section 52 to the outer section 51 and is shaped (i.e., folded) such that, depending on the orientation of the inner section 52, the inner section 52 of the strip extends parallel to the photovoltaic module or a rear face of the photovoltaic module, while the outer section 51 is perpendicular to the surface of the photovoltaic module.

[0034] Fig. Figure 4(B) shows how an opening 120 is formed in the film substrate 110 by a punching. In the illustrated embodiment, the punching creates a trapezoidal flap 130 with two parallel, opposite straight sides 121, 122, one side (e.g., the shorter one) forming the fixing side 122 and the opposite side (e.g., the longer one) forming the connecting side 121. The resulting flap 130 is movably connected to the film substrate 110 along the connecting side 121.

[0035] The Fig. Figure 4(C) shows the flap 130 being opened to access the connecting strap 50, as shown in the Fig. 4(A) can be seen, to guide the connecting strip 50 through the opening 120. When the connecting strip 50 is guided through, the outer section 51 protrudes through the opening 120. The process of guiding the connecting strip 50 through is shown in the Fig. 4(D) continued.

[0036] The Fig. Figure 4(E) shows the fixing of the connecting strip 50 (or its outer section 51) after the outer section 51 has been completely inserted through the opening 120, by closing the flap 130. Lamination can then be carried out, which prevents the flap 130 from being opened subsequently (in the Fig. 4 not shown).

[0037] Optionally, several connecting straps 50 can also be placed through the opening 120. For example, it is possible to insert a second connecting strap (in the Fig. (4 not shown) to be fixed to another section of the fixing side 122 by means of the flap 130. If the flap 130 or the opening 120 is dimensioned sufficiently large, in principle any number of connecting straps can be placed through one opening 120 and fixed with one flap 130.

[0038] The Fig. 5A and Fig. Figure 5B shows an embodiment in which two connecting strips are placed through each opening. The two connecting strips can be electrically contacted by individual electrical contacts or by a common electrical contact.

[0039] In the Fig. 5A shows the same situation as described above. Fig. Figure 3 shows a cross-sectional view through the opening 120. In the example shown, two connecting strips 50 have now been placed through the opening 120, and the cross-section was taken through one of the two connecting strips 50. The outer section 51 points upwards, and the inner section with the fold 53 is located on the opposite, inner side of the film substrate 110. Furthermore, the Fig. 5A the side boundary 105, which may, for example, represent an outer edge of the photovoltaic module or any other edge to which a sufficient insulation distance d from the connecting strip 50 is to be ensured.

[0040] In the Fig. Figure 5A below shows a top view of the film substrate 110, showing only a section of the film substrate 110 with just one opening 120 and one flap 130. In the part of the film substrate 110 not shown, further openings / flaps 120, 130 may (but do not need to) be formed. Furthermore, the two outer sections 51a, 51b of the two connecting strips along the fixing side 122 are fixed by the closed flap 130. Along the exemplary oval opening 120, a first connecting strip with a first inner section 52a and the first outer section 51a is shown at a round end section. On the opposite oval section (along the oval longitudinal extent), the second connecting strip with the inner section 52b and the outer section 51b is shown.

[0041] The shape of the opening 120 is freely selectable within the scope of the present invention and is only limited in that it should ensure a clear, largely tolerance-free fixation of the connecting strip 50 for position changes perpendicular to the fixing side 122 (in the surface area of ​​the film substrate 110). For example, the opening can be trapezoidal, rectangular, square, triangular, oval, or any other geometric shape that achieves the aforementioned fixation.

[0042] The Fig. Figure 5B shows an embodiment with a plurality of openings 120 along a direction, which have the specified minimum distance d to the edge boundary 105. In detail, a first opening 120a, a second opening 120b, and a third opening 120c are shown. The first opening 120a is closed by a first flap 130a, the second opening 120b by a second flap 130b, and the third opening 120c by a third flap 130c. The first to third flaps 130a ... 130c are rotatably connected to the film substrate 120 along connecting sides 121. Opposite the connecting side 121, the openings 120 again have fixing edges 122.

[0043] In the closed position I1 of the flaps 130, four contact strips are fixed in the illustrated embodiment. For example, in the first opening 120a, a first connecting strip with the inner section 52a and the outer section 51a is fixed on the left side of the oval opening 120. Furthermore, in the first opening 120a, on the right side of the oval longitudinal extension, a second connecting strip with an inner section 52b and a first outer section 51b is fixed by the first flap 130a. A second outer section 51e at the opposite end of the second connecting strip is fixed by the second flap 130b in the second opening 120b at the second fixing edge 122b. The second opening 120b also fixes another connecting strip with a first outer section 51d and a second outer section 51e.The first outer section 51d projects through the second opening 120b and the second outer section 51e projects through the third opening 120c. Likewise, two contact strips are again passed through the third opening 120c, one of which is the second connecting strip, which also projects through the second opening 120b, and the other connecting strip is in the exemplary embodiment of the . Fig. 5B is only partially shown, but it also has a first outer section 51d that protrudes through the third opening 120c and is held there. Thus, it is possible for all connecting strips to be connected to each other in any way (e.g., in series or parallel).

[0044] Fig.Figure 6 shows a flowchart for a method for back-side insulation of a photovoltaic module according to a further embodiment. The method comprises providing S110 at least one photovoltaic module, a connection strip 50, and one of the backsheets described above. The method further comprises electrically contacting S120 the photovoltaic module with the connection strip 50 and aligning S130 the connection strip 50 and the backsheet relative to each other such that the connection strip 50 extends through the at least one opening 120 when the backsheet is applied to a back side of the at least one photovoltaic module. Finally, the method comprises closing S140 the flap 130, thereby pressing the connection strip 50 against the fixing side 122 of the at least one opening 130.When closing S140, the connecting strip 50 may shift, thereby setting the desired insulation distance d to the edge boundary 105.

[0045] In the inventive method, all previously described functional features can also be implemented as additional process steps.

[0046] The present invention thus combines the possibility of automated threading of the connecting strips with the adherence to defined insulation distances and therefore combines both advantages of conventional backsheet films.

[0047] The features of the invention disclosed in the description, claims and figures may be essential for the realization of the invention, either individually or in any combination. Reference symbol list 50 connecting strap 51 outer section of the connecting strip 52 inner section of the connecting band 53 Folding section of the connecting tape 105 Edge limit 110 film substrate 120 opening 121 Connection page 122 Fixation page 130 flap I1 closed position I2 open position d insulation distance A1, A2, A3, A4 Position when erecting the outer section 51

Claims

[1] Photovoltaic module comprising a plurality of photovoltaic cells and a front side defining a light-incidence side and an opposite rear side defining a mounting side or connection side, comprising the following features: at least two connecting bands (50) which have a folding section (53) between an outer section (51) and an inner section (52); a backsheet formed on the back of the photovoltaic module and comprising the following: a foil substrate (110); at least one opening (120) with a connecting side (121) and a fixing side (122) in the film substrate (110) for passing through the at least two connecting strips (50); and at least one flap (130) which has a hinge connection on the connecting side (121) of the at least one opening (120) with the film substrate (110) and is movable between a closed position (I1) and an open position (I2), wherein the at least one opening (120) in the film substrate (110) is freely accessible in the open position (I2) for passing through the at least two connecting strips and in the closed position (I1) the flap (130) holds the at least two connecting strips (50) at the fixing side (122) of the opening (120), wherein the flap (130) of the back film is in the closed position (I1) to fix the outer section (51) to the fixing side (122), wherein the inner section (52) extends along a longitudinal extent of the back film to electrically contact various photovoltaic cells. [2] Photovoltaic module according to claim 1, wherein the fixing side (122) is formed in the at least one opening (120) opposite the connecting side (121) and has a straight section. [3] Photovoltaic module according to claim 1 or claim 2, wherein the film substrate (110) has an edge boundary (105) and the fixing side (122) is formed at a predetermined distance (d) from the edge boundary (105), wherein the predetermined distance (d) is selected such that sufficient insulation of outward-exposed connection strips is ensured. [4] Photovoltaic module according to claim 3, wherein the at least one opening (120) comprises several openings (120a, 120b, ...) and the fixing sides (122a, 122b, ...) of the several openings (120a, 120b, ...) are aligned parallel to the edge boundary (105). [5] Photovoltaic module according to one of the preceding claims, wherein the hinge connection is formed by partial punching or perforation along the connection side (121). [6] Photovoltaic module according to one of the preceding claims, wherein the shape of the at least one opening (120) has one of the following shapes: oval, trapezoidal, rectangular, triangular, square. [7] Photovoltaic module according to one of the preceding claims, wherein the at least two connecting strips (50) extend through the backsheet and between the plurality of photovoltaic cells and the backsheet and are formed in sections as double layers. [8] Photovoltaic module according to one of claims 1 to 7, which further comprises a rear lamination, wherein the lamination holds the flap (130) in the closed position (I1) and thereby fixes the at least two connecting straps (50) in a predetermined position. [9] Method for back-side insulation of a photovoltaic module comprising the following steps: Providing (S110) at least one photovoltaic module with a plurality of photovoltaic cells, at least two connecting strips (50) and a backsheet, wherein the backsheet has a film substrate (110) and at least one opening (120) with a connecting side (121) and a fixing side (122) in the film substrate (110) for passing through the at least two connecting strips (50); electrical contact (S120) of the photovoltaic module with the at least two connection straps (50); multiple folding of the at least two connecting straps (50) to allow threading of the at least two connecting straps (50); Aligning (S130) the at least two connecting strips (50) and the backsheet relative to each other, such that the at least two connecting strips (50) extend through the at least one opening (120) when the backsheet is applied to a rear side of the at least one photovoltaic module; and Closing (S140) of the flap (130), thereby pressing the at least two connecting straps (50) against the fixing side (122) of the at least one opening (120). [10] Method according to claim 9, which further comprises a lamination step and the lamination step is carried out such that the flap (130) is held in the closed position (I1).

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