Photovoltaic cell having specific arrangement of energy collectors and method for producing such cell

Abstract

The invention relates to a photovoltaic cell (1). The photovoltaic cell (1) comprises a first front collector layer (4), an amorphous silicon layer (6) on the first layer (4), and a second conductive layer (8) on the amorphous silicon layer (6). An electrical connection from the second electrically conductive layer (8) to the first layer (4) is made through the amorphous silicon layer (6). The electrical connection of the second electrically conductive layer (8) to the first layer (4) is made at the periphery of the photovoltaic cell through the amorphous silicon layer (6), the electrically conductive layer (8) comprising a positive peripheral bus (8 ') connected to the TCO first layer (4) and at least one positive connection terminal at one end of the positive peripheral bus, and a negative peripheral bus connected to a negative connection terminal, the positive peripheral bus (8') being connected to the TCO first layer (4) and at least one negative connection terminal at one end of the positive peripheral bus. And the positive peripheral bus bar and the negative peripheral bus bar are asymmetric with respect to each other, wherein the positive peripheral bus bar is longer than the negative peripheral bus bar.

Description

Technical Field

[0001] The invention relates to a photovoltaic cell having a specific arrangement of collectors for collecting energy in the form of electric current and to a method for producing such a photovoltaic cell.

[0002] Thus, the present invention consists in optimizing the efficiency of a photovoltaic cell for use in a portable electronic object such as a wristwatch. Background Art

[0003] Each photovoltaic cell has a general shape that matches the shape of the portable object that houses it. Typically, it can be a cylindrical cell that is arranged on the inner surface of the glass of the portable object that houses it, or on a dial surface that is visible from the outside of the portable object.

[0004] This photovoltaic cell is produced with the help of a set of layers, in particular a first front layer transparent to ambient light, called the front collector, which can be produced with the help of a layer of zinc oxide doped with aluminum (ZnO:Al or AZO). This first layer can be arranged on the inner surface of the glass of the portable object, facing the dial, and on which is generally deposited a pin-type sequence (p-doped, intrinsic i, n-doped) of a thin layer of amorphous silicon (a-Si), called the absorber, which converts the absorbed light radiation into positive charge carriers (holes) and negative charge carriers (electrons). The structure usually terminates with a second conductive layer (for example aluminum or another metal combination), called the rear collector.

[0005] In this configuration, positive charge carriers drift toward the front collector, where they are neutralized by electrons from the external circuit. Negative charge carriers drift toward the rear collector, where they donate electrons to the external circuit and form a negative charge current between the rear collector and the front collector. By convention, this involves a (positive) current flowing between the positive and negative electrodes, so in the configuration just described, the charge current is negative.

[0006] Initially, for a technology using only one metal layer, an embodiment for producing a photovoltaic cell has been proposed according to the prior art, such as Figure 1 In this embodiment, the current collector or peripheral bus is proposed in a symmetrical design, i.e., with peripheral busbars of more or less the same length, width and thickness, forming two semicircles or arcs around the circumference of the circular cell. Generally speaking, the busbar must be as long as possible in order to promote the most homogeneous distribution of the current in the front collector of the photovoltaic cell, which reduces the resistance losses.

[0007] In the case of homogeneous photovoltaic cells (called single-stage cells), if Figure 1 As shown, it can be seen that the current lines follow approximately straight and parallel paths between the two peripheral busbars. With current transparent conductive layer technology used to form the front collector, it should be noted that the layer resistance is at least one to two orders of magnitude greater than the resistance of the thin layer deposited at the rear of the cell to form the rear collector.

[0008] When current flows through the front and rear collectors, this difference in layer resistance results in a significantly higher potential gradient in the front collector than in the rear collector, and an increase in power losses as the current value increases. Summary of the invention

[0009] The present invention thus proposes a photovoltaic cell with a specific arrangement of current collectors or peripheral busbars that significantly reduces the voltage drop in the front collector caused by the current generated by the absorber layer after the capture of light.

[0010] To this end, the invention relates to a photovoltaic cell arranged to significantly reduce the voltage drop across the front collector, as defined in independent claim 1 .

[0011] Particular embodiments of the photovoltaic cell are defined in dependent claims 2 to 8 .

[0012] In order to provide electrical contact on only one side of the photovoltaic cell, a part of the rear collector is usually separated by chemical etching or another method so that it can be used as a positive terminal. This positive terminal is electrically connected to the front collector by means of a metal busbar deposited in an opening previously made through the sequence of thin amorphous silicon layers (absorber). The front collector is transparent and conductive (TCO) and can be made using a layer of zinc oxide doped with aluminum (ZnO:Al or AZO), which has a much lower conductivity than the rear collector, which can be a metal layer made of aluminum, for example. This difference in conductivity is about 30 times worse.

[0013] Under these conditions, according to the invention, at least one metal peripheral busbar connected to the front collector is provided, which busbar is much longer than the length of the metal peripheral busbar provided in the rear collector. Preferably, the length of the front peripheral busbar should be at least 10 times the length of the rear peripheral busbar. This asymmetry in length between peripheral busbars, for example having the same width and the same thickness, makes it possible to limit or reduce the potential drop within the front collector to less than 100 mV. This represents a gain of almost 50 mV compared to the potential drop observed in a photovoltaic cell with a symmetrical peripheral busbar. The potential drop within the front collector can be less than 100 mV, which makes it possible to limit the power losses of photovoltaic cells that generate a voltage of no more than 600 mV to 700 mV before being processed in the electronic module of the portable object.

[0014] Advantageously, the connection from the front collector to a portion of the rear collector, preferably the aluminium metal layer on opposite faces, may be provided with two busbars of asymmetrical length connecting the front collector on one hand and the aluminium metal layer defining the negative terminal on the other hand.

[0015] Furthermore, two peripheral busbar sections may be provided from the connection point of the aluminum layer to the front collector, which are connected to the positive terminal, thereby describing a defined angle on either side of the connection point of the front collector. The angle described by the peripheral busbars of the positive front collector is much greater than the angle of the negative terminal of the aluminum layer. For the peripheral busbars connected to the front collector, 330° of coverage is expected, while for the negative terminal portion of the aluminum layer, the angle may be less than 30°.

[0016] Advantageously, each free end of the positive peripheral busbar connected to the front collector comprises a connection end in order to further reduce the current flowing through the metallic peripheral busbar. Thus, the two positive terminals connected to the peripheral busbar connected to the front collector are intended to be connected in parallel by means of a flexible connector, for example, to an electronic data processing module. Thus, the value of the current flowing to each end of the metallic peripheral busbar is half the value of the total current flowing to the negative terminals. This also means that there are two positive end terminals and one negative end terminal connected to the electronic module, which is mainly located under the dial of the portable object.

[0017] To this end, the invention further relates to a method for producing a photovoltaic cell as defined in independent claim 9 . BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The objects, advantages and features of a photovoltaic cell with a particular arrangement of energy collectors, as well as those of a method for producing such a photovoltaic cell, will become more apparent in the following non-limiting description given with reference to the accompanying drawings, in which: Figure 1 A bottom view of a photovoltaic cell according to the prior art is shown, the photovoltaic cell having symmetrical peripheral busbars for negative and positive terminals.

[0019] Figure 2 shows a bottom view of a photovoltaic cell according to the invention having asymmetric peripheral busbars of different lengths for connecting the front collector to the positive terminal and the rear collector to the negative terminal, these busbars being made of a metal layer already used to form the rear collector, Figure 3a , 3b , 3c and 3d show cross-sections of four steps of the method for producing a photovoltaic cell in the first embodiment, which retains an area of ​​the conductive layer without an openwork portion in the central reading area of ​​the photovoltaic cell, while clearly defining the boundary between the positive area and the negative area.

[0020] Figure 4 It is shown that according to the present invention Figure 3d A bottom view of a photovoltaic cell of a first alternative embodiment shown in cross section in FIG. 1 , the photovoltaic cell having asymmetric peripheral busbars, ie having different lengths relative to the peripheral busbars of the negative region, Figure 5a , 5b 5c and 5d show cross-sections of four steps of a method for producing a photovoltaic cell according to a second alternative embodiment of a photovoltaic cell, and Figure 6a , 6b , 6c and 6d show cross sections of four steps of a method for producing a photovoltaic cell according to a third alternative embodiment of a photovoltaic cell. DETAILED DESCRIPTION

[0021] The following description primarily describes a single-segment photovoltaic cell having a particular arrangement of current collectors including asymmetric peripheral busbars or collectors to reduce voltage drop between at least one positive terminal and one negative terminal of the photovoltaic cell.

[0022] The single-segment photovoltaic cell consists essentially of a first front layer transparent to ambient light, called the front collector, which can be made with the help of a layer of zinc oxide doped with aluminum (ZnO:Al or AZO). This first layer can be arranged on the inner surface of the glass of the portable object, facing the dial, and on it, a pin-type sequence (p-doped, impurity-free i, n-doped) of thin layers of amorphous silicon (a-Si) is usually deposited, called the absorber, which generates positive charge carriers (holes) and negative charge carriers (electrons) under illumination. The structure usually terminates with a second conductive layer, which can be a metallic layer, for example made of aluminum or another metal combination, called the rear collector.

[0023] The single-segment photovoltaic cell may include a substrate formed thereon. One of the faces of the glass of a portable object, or a portion of the dial of a portable object may be used as the substrate of the photovoltaic cell. In the remainder of this description, preference will be given to producing a complete photovoltaic cell on the inner surface of the glass.

[0024] Compared with existing technology Figure 1 In comparison, it can be noted that Figure 2 A relatively generalized embodiment is shown with an asymmetric peripheral busbar or collector, allowing the positive peripheral busbar 8' connected to defined positive terminals 8'a and 8'b to fix a quasi-constant potential over the largest part of the periphery of the photovoltaic cell front layer to which it is connected.

[0025] This modification - the purpose of which is to maintain an almost constant potential over a larger part of the periphery of the front layer of the photovoltaic cell - makes it possible to force a quasi-radial configuration of the current lines, e.g. Figure 2 as shown, and thereby reducing the potential difference between the highest value at the center and the lowest value at the periphery.

[0026] The rear collector connected to the defined negative terminal 8 consists of a metal layer of low resistivity. This limits the potential difference between the terminal 8 and its diametrical end to negligible values ​​compared to the front collector, despite the unfavourable geometry of the rear collector.

[0027] The photovoltaic cell 1 is usually in the form of a cylinder. This part of the cylinder may be intended to be fastened under the glass of a portable object, or above the dial of a portable object. For example, the portable object may be a watch.

[0028] exist Figure 2 In this configuration shown, the positive peripheral busbar 8' connected to the front collector of the photovoltaic cell describes a portion of an arc having an angle of at least 330°. On the other hand, the arc of the negative peripheral busbar 8 describes an angle of about 30° or less. For the positive peripheral busbar, even an arc of almost 350° can be envisaged, and for the negative peripheral busbar 8, an arc of less than 10° can be envisaged.

[0029] The positive peripheral busbar 8' is connected to the front collector (not shown) over the largest part of its length, and preferably over its entire length. Figure 2). This means that the positive peripheral busbar ends in a first positive terminal 8'a and, opposite thereto, in a second positive terminal 8'b, so as to be able to connect them subsequently and via a specific connector to an electronic module located under the dial of the portable object. The negative terminal of the negative peripheral busbar will also be connected subsequently and via a specific connector to the electronic module. The two positive terminals 8'a and 8'b of the positive peripheral busbar 8' make it possible to reduce the voltage drop on the positive peripheral busbar by three quarters by placing two sectors of this busbar in parallel, subsequently connected to the electronic module, dividing the collected current by two on the one hand and the distance that needs to be covered by two on the other hand.

[0030] Figure 3a , 3b 3c and 3d show the various steps of the method for producing a photovoltaic cell according to the first embodiment. Figure 3a As can be seen in FIG. 1 , there is a base layer 2 which is a glass layer and in this case forms part of the actual photovoltaic cell. However, multiple layers one above the other may be used as base layer 2, and these layers may consist of at least one glass layer on or below which one or more layers of transparent material are placed, or a sapphire layer is deposited on one or more glass layers at the end of the method.

[0031] More typically, the photovoltaic cell 1 comprises as base layer a first front collector layer 4, which at the end of the production method is defined as the front collector. A pin-type sequence of thin layers of amorphous silicon (a-Si) (p-doped, pure i, n-doped) - called absorber or defined as amorphous silicon layer 6 - is deposited on the first front collector layer, and a second conductive layer 8, preferably a metal layer such as an aluminum layer, is added to the amorphous silicon layer 6.

[0032] All the steps involved in producing and patterning the photovoltaic cell 1 are described below using the glass 2 of a portable object acting as a substrate and on which the three successive layers mentioned above, namely the first front collector layer 4, the amorphous silicon layer 6 and the second conductive layer 8 are produced and patterned.

[0033] This means that the photovoltaic cell 1 may comprise both the glass layer 2 and the three layers specified above, or only the three layers specified above.

[0034] It should also be noted that the photovoltaic cell 1 can also be mounted or fastened on the dial of a portable object. In this case, however, the front collector layer 8 is used directly as a base layer, since, at the end of the method for producing a single-segment photovoltaic cell 1, the latter is mounted or fastened on the dial of a portable object on the side of the second conductive layer (rear collector), which can be a metal layer. This first layer of the front collector can advantageously be a layer of zinc oxide ZnO, or a layer of zinc oxide doped with aluminum (ZnO:Al or AZO).

[0035] Since a glass layer, or a layer of glass and sapphire is usually used as the glass 2 of the portable object, the various subsequent steps are performed on the inner surface of the glass 2 of the portable object. The glass layer 2 is shown as a base layer on which the various other layers of the single-segment photovoltaic cell 1 are deposited.

[0036] Figure 3a It is shown that on one face of the glass layer 2, a weakly conductive first front collector layer 4 is first deposited. This can be a first front layer 4, which is zinc oxide ZnO or a first zinc oxide layer doped with aluminum (ZnO:Al or AZO). Above this first front layer 4, a pin-type sequence of thin layers of amorphous silicon (a-Si) is provided (p-doped, pure i, n-doped), called the placed absorber or deposited amorphous silicon layer 6, which serves to capture electromagnetic waves, i.e., for example light, in order to convert it into electrical energy by the layers arranged above and below this amorphous silicon layer 6. The general shape of the front layer 4 and the amorphous silicon layer 6 depends mainly on the general shape of the glass on which they are produced or deposited. Mainly in the embodiment shown, the base layer of the glass 2 as a portable object (such as a watch) can be generally circular in shape when viewed from above, or form part of a glass bell to close the watch case. Therefore, the first front layer 4 adopts the general shape of a cylinder in order to be deposited or fastened on the inner surface of the watch glass 2. Similarly, a thin amorphous silicon layer 6 is arranged or deposited on the first front layer 4 and is similar in shape to the first front layer 4 .

[0037] Figure 3b The second step of the method shown is to make openings 12, usually in a peripheral position of the photovoltaic cell 1, through a pin (p-doped, i-free, n-doped) sequence of thin layers of amorphous silicon (a-Si), defined as the amorphous silicon layer 6, which show the access to the first front layer. Each opening 12 made to connect the first front collector layer can be made using a laser or other etching techniques as used in microelectronics. Then, in Figure 3c In the third step of the method for producing a photovoltaic cell 1 shown, a second conductive layer 8 is deposited on top of the amorphous silicon layer 6. The second conductive layer 8 is preferably a metal layer, such as an aluminum layer. The metal layer is preferably made of aluminum. Figure 3b The opening 12 produced in the method step shown allows contact with the first front layer 4 .

[0038] at last, Figure 3d The last step of the manufacturing method shown consists in separating the second conductive layer 8, which can be a metal layer 8 made of aluminum, for example, so as to contact the TCO front layer 4 on the one hand and the metal layer connected to the portion of at least one negative terminal of the photovoltaic cell on the other hand. For this purpose, an opening 12' is made in and through the conductive layer 8, which can be an aluminum layer 8 and is formed in such a way that the aluminum metal layer 8', for example connected to the first front layer 4, is separated from the aluminum metal layer 8 connected to the negative terminal of the photovoltaic cell 1.

[0039] exist Figure 3d At the end of the method of this first alternative embodiment of the photovoltaic cell 1 shown, the photovoltaic cell 1 can capture a beam or light 10. As will be explained below, the photovoltaic cell 1 is intended to be connected to an electronic module, usually located under the dial of a portable object, in order to convert the light into electrical energy.

[0040] Figure 4 A view from below is shown at the end of the manufacturing method to illustrate the separation of the second metal layer (for example made of aluminum) in order to connect the front collector layer on the one hand and the negative terminal of the photovoltaic cell 1 on the other hand. Figure 4 The asymmetric peripheral busbars of the invention are clearly shown, namely the positive peripheral busbar connected to the front collector layer, and the negative peripheral busbar connected to the negative connection terminal of the photovoltaic cell.

[0041] One or more openings made in the second conductive layer 8 (such as an aluminum layer) allow the creation of a positive peripheral busbar 8' for subsequent connection to an electronic module under the dial of the portable object. By making these openings, the amorphous silicon layer 6 under the conductive layer (which is the aluminum layer 8) can be seen.

[0042] Each positive peripheral busbar from the connection with the first front collector layer terminates on a first side in a first positive terminal 8'a and on a second side in a second positive terminal 8'b. The two peripheral busbar sectors together describe a total circular arc defined over at least 330°. The negative peripheral busbar of the aluminum layer is represented only by the negative terminal 8 facing the two positive terminals 8'a and 8'b. The negative peripheral busbar has an arc of less than 30°, which shows the asymmetry of the positive and negative peripheral busbars sought by the present invention.

[0043] The two positive peripheral busbar sectors 8' together are approximately 10 times larger than the negative peripheral busbar 8, which provides the advantage of reduced voltage drop as described above, particularly at higher illumination levels which result in higher currents.

[0044] Furthermore, in this first alternative embodiment, the negative terminal 8 is directly connected to the remainder of the metal layer 8 , which does not have a hollowed-out portion and is surrounded by the two positive peripheral busbar sectors 8 ′.

[0045] Figure 5a , 5b , 5c and 5d show cross sections of four steps in a method for producing a photovoltaic cell according to a second alternative embodiment for producing a photovoltaic cell. Figure 6a , 6b , 6c and 6d show cross sections of four steps in a method for producing a photovoltaic cell according to a third alternative embodiment of a photovoltaic cell.

[0046] It should be noted that all steps in the method for producing these second and third alternative embodiments of the method will not be repeated because they are substantially similar to those of the reference Figure 3a , 3b , 3c and 3d described.

[0047] In a second alternative embodiment of the method for producing a photovoltaic cell 1, Figure 5d In the fourth step shown, chemical etching is performed to etch both the conductive layer 8 (such as the metal layer 8) and the amorphous silicon layer 6 so as to obtain openings which are given reference numerals 12' and which define the hollowed-out portions.

[0048] Similarly, for the third alternative embodiment of the method for producing a photovoltaic cell 1, Figure 6d In the fourth step shown, chemical etching is performed to etch both the conductive layer 8 (such as a metal layer 8) and the amorphous silicon layer 6, as well as the first front layer 4 over the base layer, which may be the glass 2 of the portable object.

[0049] If the cutouts are used to make the photovoltaic cell semi-transparent, the cutaway can be chosen between 75% and 95%, i.e. at most 25% PV coverage (which becomes too visible) and at least 5% PV coverage (which becomes difficult to design because the cell power becomes too low).

[0050] However, as indicated at the beginning of the detailed description, the method for producing a photovoltaic cell can start directly with a first front collector layer 4 constituting a base layer. From this base layer, the other layers are arranged successively from one face of this first front collector layer 4. This first front collector layer 4 can advantageously consist of a layer of zinc oxide ZnO or of a first layer of zinc oxide doped with aluminum (ZnO:Al or AZO).

[0051] In the above case, the photovoltaic cell 1 produced is not bonded to the glass of the portable object or is not directly located on the dial of the portable object. In the case of a photovoltaic cell 1 consisting only of the three layers described above, it must be possible to subsequently connect the connection terminals of the positive and negative peripheral busbars to an electronic module usually located under the dial of the portable object in order to manage the signals received via its connection terminals with the positive and negative peripheral busbars.

[0052] It should be noted that in order to connect these positive and negative peripheral busbar connection terminals to the electronic module of the portable object, a flexible connection of the FPC (Flexible Printed Circuit) type bonded to an ACF (Anisotropic Conductive Film) can be used, or a connector with spring bars, also known as pogo, or even a Zebra type connector (elastic blocks containing regularly spaced conductive areas). However, the connection of the photovoltaic cell to the electronic module of the portable object will not be described in more detail, since the invention is mainly based on the difference in length of the positive and negative peripheral busbars in order to optimize the efficiency of such a photovoltaic cell. In this case, thanks to the specific arrangement of the positive and negative peripheral busbars, there is a reduction in the potential drop in the connection to the low-conductivity TCO layer compared to the photovoltaic cell in the prior art.

[0053] Various other forms of photovoltaic cells may be envisaged by those skilled in the art without departing from the scope of the invention as defined by the claims.

Claims

1. A photovoltaic cell (1) intended to be arranged on the inner surface of a transparent glass or on the dial of a portable object, the photovoltaic cell (1) comprising a first transparent conductive layer (TCO) constituting a front collector (4), an amorphous silicon layer (6) on the first front collector layer (4), and a conductive layer (8) on the amorphous silicon layer (6), the conductive layer (8) constituting a rear collector, the electrical connection from the conductive layer (8) to the first front collector layer (4) being made through the amorphous silicon layer (6), It is characterized in that The electrical connection of the second conductive layer (8) to the first front collector layer (4) is made through the amorphous silicon layer (6) at the periphery of the photovoltaic cell, and the conductive layer (8) includes a positive peripheral busbar (8') and a negative peripheral busbar, the positive peripheral busbar (8') is connected to the first front collector layer (4) and at least one positive connection terminal (8'a, 8'b) at one end of the positive peripheral busbar, the negative peripheral busbar is connected to the negative connection terminal, and the positive peripheral busbar and the negative peripheral busbar are asymmetric relative to each other, wherein the length of the positive peripheral busbar is greater than the length of the negative peripheral busbar.

2. The photovoltaic cell (1) according to claim 1, characterized in that: The thickness and width of the positive peripheral bus bar are substantially the same as the thickness and width of the negative peripheral bus bar, and the length of the positive peripheral bus bar is at least 10 times longer than the length of the negative peripheral bus bar.

3. Photovoltaic cell (1) according to one of the preceding claims, characterized in that The electrical connection of the conductive layer (8) to the first TCO layer (4) is made through the amorphous silicon layer (6) over the entire length of the positive peripheral busbar to be produced on the second conductive layer (8), which is a second metal layer.

4. The photovoltaic cell (1) according to claim 3, characterized in that: The metal layer is an aluminum layer.

5. The photovoltaic cell (1) according to claim 3, wherein the photovoltaic cell is a cylinder in a plan view, characterized in that: The positive peripheral busbar describes a total arc of 330°, the total arc of 330° having a peripheral electrical connection to the TCO first layer (4) over the entire length of the positive peripheral busbar, the positive peripheral busbar terminating at a first positive connection terminal (8'a) on a first side and at a second positive connection terminal (8'b) on a second opposite side, and the negative peripheral busbar including the negative connection terminal follows an arc of less than 30°, the arc of less than 30° having the first positive connection terminal (8'a) of the positive peripheral busbar and the second positive connection terminal (8'b) of the positive peripheral busbar on each side.

6. The photovoltaic cell (1) according to claim 3, wherein the photovoltaic cell is a cylinder in a plan view, characterized in that: The positive peripheral busbar describes a total arc of 350°, the total arc of 350° having a peripheral electrical connection to the TCO first layer (4) over the entire length of the positive peripheral busbar, the positive peripheral busbar terminating on a first side with a first positive connection terminal (8'a) and on a second opposite side with a second positive connection terminal (8'b), and the negative peripheral busbar including the negative connection terminal follows an arc of less than 10°, the arc of less than 10° having on each side the first positive connection terminal (8'a) of the positive peripheral busbar and the second positive connection terminal (8'b) of the positive peripheral busbar.

7. Photovoltaic cell (1) according to one of the preceding claims, characterized in that Various subsequent layers starting from a first front TCO layer (4) are produced on the inner surface of the glass of the portable object so as to form a single-segment photovoltaic cell assembly together with the glass (2) of the portable object, the glass (2) of the portable object forming part of the photovoltaic cell.

8. Photovoltaic cell (1) according to one of the preceding claims, characterized in that The conductive layer (8) is a metal layer, which includes a hollow portion in the central portion of the negative terminal connected to the negative peripheral busbar so as to make the photovoltaic cell semi-transparent.

9. A method for producing a photovoltaic cell (1) according to one of claims 1 to 6, wherein the method comprises the following steps: - depositing an amorphous silicon layer (6) on the TCO first layer (4), - making an opening (12) through the amorphous silicon layer (6) to give access to the first layer (4) of TCO, - depositing a conductive layer (8) on the amorphous silicon layer (6), wherein a portion of the conductive layer (8) contacts the TCO first layer (4), the method being characterized by the following steps: - making openings through the amorphous silicon layer (6) located in the peripheral region of the photovoltaic cell (1), - separating the conductive layer (8) by creating an opening (12') through the conductive layer (8) in order to contact the TCO front layer (4) on the one hand and create a positive peripheral busbar (8'), and on the other hand contact the metal layer connected to the part of the negative peripheral busbar connected to the negative terminal (8) of the photovoltaic cell.

10. The method according to claim 9, wherein the conductive layer (8) is a metal layer, such as an aluminum layer. 11 . The method according to claim 9 , wherein a hollow portion is produced in a central portion of the metal layer connected to the negative connection terminal.

12. The method according to claim 9, characterized in that All steps for producing the photovoltaic cell (1) are carried out on a substrate, which is the glass (2) of a portable object, the glass (2) of the portable object forming part of the photovoltaic cell.

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