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

Abstract

To provide a photovoltaic cell with a specific arrangement of current collectors or peripheral buses for substantially reducing a voltage drop in a front collector.SOLUTION: A photovoltaic cell 1 includes: a first front collector layer; an amorphous silicon layer 6 on a first layer; and a second conductive layer 8 on the amorphous silicon layer 6. An electric connection part from the second conductive layer 8 to the first layer is manufactured so as to penetrate the amorphous silicon layer 6. The electric connection part from the second conductive layer 8 to the first layer is manufactured so as to penetrate the amorphous silicon layer 6 in a periphery of the photovoltaic cell. The conductive layer 8 includes a positive peripheral bus 8' and a negative peripheral bus. The positive peripheral bus 8' is connected with a TCO first layer and at least one positive connection terminal in one end of the positive peripheral bus, and the negative peripheral bus is connected to a negative connection terminal. The positive peripheral bus and the negative peripheral bus are asymmetric to each other in a state where the positive peripheral bus is longer than the negative peripheral bus.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a photovoltaic cell having a particular arrangement of collectors that collects energy in the form of electrical current, and to a method for making such a photovoltaic cell.

[0002] That is, the present invention consists in optimizing the efficiency of photovoltaic cells for use in portable electronic objects such as watches. [Background technology]

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

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

[0005] In this configuration, the positive charge carriers drift towards the front collector, where they are neutralised by electrons from the external electric circuit. The negative charge carriers drift towards the rear collector, where they donate electrons to the external circuit, forming a negative charge current between the rear collector and the front collector. By convention, this refers to a (positive) current flowing between the positive and negative electrodes, so in the previous configuration the charge current is negative.

[0006] Initially, as a technique using only one metal level, an embodiment shown in Figure 1 has been proposed for the manufacture of photovoltaic cells according to the prior art. In this embodiment, the current collectors or peripheral buses form two semi-rings or semi-circular arcs around the circumference of the circular cell with a symmetrical design, i.e. with peripheral buses of approximately the same length, width and thickness. Typically, these buses should be as long as possible to promote the most uniform possible distribution of the current in the front collector of the photovoltaic cell, thus reducing resistive losses.

[0007] In the case of a uniform photovoltaic cell, referred to as a single segment cell, shown in Figure 1, it can be seen that the current lines follow approximately straight and parallel paths between the two peripheral buses. It should be noted that with the current transparent conductive layer technology used to form the front current collector, its layer resistance is at least one to two orders of magnitude greater than the layer resistance of the thin layer deposited on the rear surface of the cell to form the rear collector.

[0008] This difference in layer resistance causes the front collector to experience a much higher potential gradient than the rear collector when current is passed, along with increasing power losses as the current value increases. Summary of the Invention

[0009] Therefore, the present invention proposes a photovoltaic cell with a specific arrangement of current collectors or peripheral buses that substantially reduces the voltage drop in the front collector, which is induced by the current generated by the absorbing layer after light capture.

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

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

[0012] To provide electrical contact to only one side of a photovoltaic cell, typically a portion of the back collector is separated by chemical etching or other methods so that it can be used as the positive terminal. This positive terminal is electrically connected to the front collector by a metal bus deposited in an opening previously made through a series of thin amorphous silicon layers (the absorber). The front collector, which may be formed using a transparent and conductive (TCO) layer of aluminum-doped zinc oxide (ZnO:Al or AZO), has a much lower conductivity than the back collector, which may be a metal layer made from 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 bus is provided, connected to the front collector, which is much longer than the length of the metal peripheral bus provided on the rear collector. Preferably, the length of the front peripheral bus should be at least 10 times greater than the length of the rear peripheral bus. For example, the asymmetry in length between peripheral buses having the same width and thickness can limit or reduce the potential drop in the front collector to less than 100 mV. This corresponds to a gain of approximately 50 mV compared to the potential drop observed in a photovoltaic cell with a symmetrical peripheral bus. Since the potential drop in the front collector can be less than 100 mV, this makes it possible to limit the power losses in a photovoltaic cell that generates a voltage not exceeding 600 to 700 mV before processing in the electronic module of the portable object.

[0014] Advantageously, two buses of asymmetric length may be provided from the connection of the front collector to a part of the rear collector, preferably an aluminum metal layer on the opposite side, on the one hand connected to the front collector and on the other hand connected to the aluminum metal layer defining the negative terminal.

[0015] Furthermore, two peripheral bus sections may be provided from the connection of the aluminum layer to the front collector. These bus sections are connected to positive terminals on both sides of the connection point with the front collector, which terminals exhibit a defined angle. The angle defined by the peripheral bus of the positive front collector is much larger than that of the negative terminal of the aluminum layer. A coverage of 330° can be expected for the peripheral bus connected to the front collector, while for the negative terminal part of the aluminum layer this angle can be less than 30°.

[0016] Advantageously, each free end of the positive peripheral bus connected to the front collector comprises a connection terminal for further reducing the current flowing through this metal peripheral bus, i.e. the two positive terminals linked to this peripheral bus connected to the front collector are intended to be connected in parallel, for example to an electronic data processing module, by means of a flexible connector. The value of the current flowing to each end of the metal peripheral bus is thus half the value of the total current flowing to the negative terminal. This also means that there are two positive terminals and one negative terminal connected to an electronic module located mainly below 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 having a particular arrangement of energy collectors, as well as the objects, advantages and features of a method for manufacturing such a photovoltaic cell, will become apparent in the following non-limiting description, given with reference to the drawings.

[0019] [Figure 1]FIG. 1 shows a bottom view of a photovoltaic cell having symmetrical peripheral bussing for the negative and positive terminals according to the prior art. [Diagram 2] FIG. 1 shows a bottom view of a photovoltaic cell with asymmetric peripheral buses of different lengths for connecting the front collector to the positive terminal and the rear collector to the negative terminal, the buses being made from the metal layer already used to form the rear collector according to the present invention. [Figure 3a-3d] Figures 3a, 3b, 3c and 3d show cross-sectional views of four steps of a method for manufacturing a photovoltaic cell in a first embodiment. In the central reading area of ​​the photovoltaic cell, an area of ​​the conductive layer without openwork is maintained, but the positive area is clearly separated from the negative area. [Figure 4] FIG. 3d shows a bottom view of a photovoltaic cell according to a first alternative embodiment of the invention shown in cross section in FIG. 3d, with asymmetric peripheral buses, i.e. different lengths for the peripheral buses of the negative areas. [Figure 5a-5d] 5a, 5b, 5c and 5d show cross-sectional views of four steps of a method for manufacturing a photovoltaic cell according to a second alternative embodiment of the photovoltaic cell. [Figure 6a-6d] 6a, 6b, 6c and 6d show cross-sectional views of four steps of a method for manufacturing a photovoltaic cell according to a third alternative embodiment of the photovoltaic cell. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The following description primarily describes a single segment photovoltaic cell having a particular arrangement of current collectors, including asymmetric peripheral buses or collectors, to reduce the voltage drop between at least one positive terminal and one negative terminal of the photovoltaic cell.

[0021] A single-segment photovoltaic cell mainly comprises a first front layer, called the front collector, transparent to ambient light. This front collector may be made by a layer of aluminum-doped zinc oxide (ZnO:Al or AZO). This first layer may be arranged on the inner surface of the glass of the portable object facing the dial, on which is typically deposited a pin-type sequence (p-doped, intrinsic i, n-doped) of amorphous silicon (a-Si) thin layers, called the absorber. The absorber generates positive charge carriers (holes) and negative charge carriers (electrons) under light illumination. The structure typically ends with a second conductive layer, which may be a metal layer (for example made of aluminum or a combination of other metals), called the rear collector.

[0022] The single segment photovoltaic cell may include a base layer formed thereon. One of the two sides of the glass of the portable object, or even a portion of the dial of the portable object, may serve as the base layer of the photovoltaic cell. In the remainder of the description, preference is given to fabricating the complete photovoltaic cell on the inner surface of the glass.

[0023] It is noted, in comparison with prior art Figure 1, that Figure 2 shows a relatively condensed embodiment having an asymmetric peripheral bus or collector: a positive peripheral bus 8' is allowed to be connected to positive defined terminals 8'a and 8'b to fix a quasi-constant potential over most of the periphery of the front layer of the connected photovoltaic cells.

[0024] This modification, aimed at maintaining a substantially constant potential over most of the periphery of the front layer of the photovoltaic cell, makes it possible to enforce a quasi-radial configuration of the current lines, as shown in FIG. 2, thereby reducing the potential difference between the maximum at the center and the minimum at the periphery.

[0025] The rear collector, connected to the defined negative terminal 8, is constructed from a metal layer of low electrical resistance, which limits the potential difference between the terminal 8 and its diameter end to a negligible value compared to the front collector, despite the unfavourable geometry.

[0026] The photovoltaic cell 1 is typically in the form of a cylinder. This part of the cylinder may be intended to be fixed under the glass of a portable object or above the dial of a portable object. The portable object may for example be a clock.

[0027] In this configuration shown in Figure 2, the positive peripheral bus 8' connected to the front collector of the photovoltaic cells presents a portion of a circular arc having an angle of at least 330°. On the other hand, the arc of the negative peripheral bus 8 presents an angle of the order of 30° or less. A circular arc of approximately 350° may be envisaged for the positive peripheral bus, and even an arc of less than 10° may be envisaged for the negative peripheral bus 8.

[0028] The positive peripheral bus 8' is connected over the greatest part of its length, preferably over its entire length, to a front collector, not shown in this FIG. 2. This means that this positive peripheral bus is terminated at a first positive terminal 8'a and at the other end at a second positive terminal 8'b, which terminals are then connectable via a specific connector to an electronic module located below the dial of the portable object. The negative terminal of the negative peripheral bus is also then connected via a specific connector to the electronic module. These two positive terminals 8'a and 8'b of the positive peripheral bus 8' make it possible to reduce the voltage drop in the positive peripheral bus by 3 / 4. This is due to the arrangement of two sectors of this bus in parallel and their subsequent connection to the electronic module, dividing by two the collected current on the one hand and the distance covered on the other hand.

[0029] Figures 3a, 3b, 3c and 3d show the various steps of a method for manufacturing a photovoltaic cell according to a first embodiment. As can be seen in the first figure 3a, there is a base layer 2, which is a glass layer, which in this case forms part of the actual photovoltaic cell. However, several layers may be used as base layer 2, one layer on top of the other, these layers consisting of at least one glass layer, on or under which one or more layers of transparent material are placed, or even at the end of the method a sapphire layer may be deposited on the one or more glass layers.

[0030] More typically, the photovoltaic cell 1 comprises as base layer a first front collector layer 4, which is defined as the front collector at the end of the manufacturing method. A pin-type sequence of amorphous silicon (a-Si) thin layers (p-doped, intrinsic 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 aluminium layer, is applied to this amorphous silicon layer 6.

[0031] All steps involved in the fabrication and patterning of the photovoltaic cell 1 are described below using the glass 2 of the portable object acting as a base layer on which the three successive layers mentioned above (i.e. the first front collector layer 4, the amorphous silicon layer 6 and the second conductive layer 8) are fabricated and patterned.

[0032] This means that the photovoltaic cell 1 may comprise both the glass layer 2 and the above three layers, or only the above three layers.

[0033] It should also be noted that the photovoltaic cell 1 can also be mounted or fixed to the dial of a portable object. In this case, however, it is the front collector layer 8 that directly serves as the base layer, since this front collector layer 8 is mounted or fixed to said dial of the portable object on the side of the second conductive layer (rear collector), which can be a metal layer, at the end of the manufacturing method of the single-segment photovoltaic cell 1. This first layer of the front collector can advantageously be a layer of zinc oxide ZnO or a layer of aluminum-doped zinc oxide (ZnO:Al or AZO).

[0034] Typically a glass layer or a layer of glass and sapphire is used as the glass of the portable object 2, so that the various subsequent steps are carried out 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.

[0035] FIG. 3a shows that on one side of the glass layer 2, a first front collector layer 4, having weak electrical conductivity, is first deposited. This may be a first front layer 4 of zinc oxide ZnO or a first zinc oxide doped with aluminum (ZnO:Al or AZO) layer. Above this first front layer 4, a thin amorphous silicon (a-Si) layer of pin-type sequence (p-doped, intrinsic i, n-doped) is provided. This is called the deposited absorber or deposited amorphous silicon layer 6, which is used to capture electromagnetic waves (i.e., for example, light) and convert them into electrical energy through layers arranged above and below the amorphous silicon layer 6. The general shape of the front layer 4 and the amorphous silicon layer 6 mainly depends on the general shape of the glass on which they are manufactured or deposited. The base layer, which in this illustrated embodiment is primarily the glass 2 of a portable object such as a watch, is typically circular in shape when viewed from above, or may form part of a glass bell for closing the watch case. That is to say, the first front layer 4 assumes a generally cylindrical shape as it is deposited or fixed to the inner surface of the watch crystal 2. Similarly, a thin amorphous silicon layer 6 is arranged or deposited on the first front layer 4 and is of a similar shape to this first front layer 4.

[0036] The second step of the method shown in FIG. 3b is to make openings 12, typically at the periphery of the photovoltaic cell 1. These openings 12 show access to the first front layer through a thin layer of amorphous silicon (a-Si) of pin (p-doped, i-intrinsic, n-doped) sequence defined as amorphous silicon layer 6. Each opening 12 made to connect the first front collector layer is made using a laser or other etching techniques used in microelectronics. Then, in the third step of the method of manufacturing a photovoltaic cell 1 shown in FIG. 3c, a second conductive layer 8 is deposited on top of the amorphous silicon layer 6. This second conductive layer 8 is preferably a metal layer, such as an aluminum layer. This metal layer is preferably made of aluminum and contacts the first front layer 4 through the openings 12 made in the method step shown in FIG. 3b.

[0037] Finally, the final step of the manufacturing method, illustrated in Fig. 3d, consists in separating the second conductive layer 8, which may for example be a metal layer made of aluminium 8, in order to contact, on the one hand, the TCO front layer 4 and, on the other hand, a metal layer connected to parts of at least one negative terminal of the photovoltaic cell. For this purpose, an opening 12' is made in the conductive layer, passing through the conductive layer 8, which may for example be an aluminium layer 8. This opening 12' is formed so as to separate, for example, the aluminium metal layer 8' connected to the first front layer 4 from the aluminium metal layer 8 connected to the negative terminal of the photovoltaic cell 1.

[0038] At the end of the method of this first alternative embodiment of the photovoltaic cell 1 in Fig. 3d, a light beam or light 10 can be captured by the photovoltaic cell 1. As will be explained below, the photovoltaic cell 1 is intended to be connected to an electronic module, typically placed under the dial of a portable object, in order to convert the light into electrical energy.

[0039] Figure 4 shows a bottom view at the end of the manufacturing method, showing the separation of the second metal layer, for example made of aluminium, which is connected on the one hand to the front collector layer and on the other hand to the negative terminal of the photovoltaic cell 1. In figure 4 the asymmetric peripheral bus of the invention is clearly shown, i.e. the positive peripheral bus connected to the front collector layer and the negative peripheral bus connected to the negative connection terminal of the photovoltaic cell.

[0040] One or more openings made in a second conductive layer 8, such as an aluminium layer, allow to create a positive peripheral bus 8' intended for a subsequent connection with an electronic module underneath the dial of the portable object. By making these openings, it is possible to see the amorphous silicon layer 6 underneath this conductive layer (i.e. the aluminium layer 8).

[0041] The positive peripheral buses from the connection with the first front collector layer each terminate 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 bus sectors together present a total arc defined over at least 330°. The negative peripheral bus of the aluminum layer is represented only by the negative terminal 8 opposite the two positive terminals 8'a and 8'b. The negative peripheral bus has an arc of less than 30°. This shows the asymmetry of the positive and negative peripheral buses that the invention seeks.

[0042] The two positive periphery bus sectors 8' taken together are approximately ten times longer than the negative periphery bus 8. This has the advantage of reducing the voltage drops mentioned above, especially at high illumination intensities generating high currents.

[0043] Moreover, in this first alternative embodiment, the negative terminal 8 is directly connected to the remainder of the metal layer 8. This metal layer 8 does not have any openwork portions and is surrounded by two positive peripheral bus sectors 8'.

[0044] Figures 5a, 5b, 5c and 5d show cross sections of four steps in a method for manufacturing a photovoltaic cell according to a second alternative embodiment of the method for manufacturing a photovoltaic cell, and Figures 6a, 6b, 6c and 6d show cross sections of four steps in a method for manufacturing a photovoltaic cell according to a third alternative embodiment of the method for manufacturing a photovoltaic cell.

[0045] It should be noted that all steps in the method of manufacturing these second and third alternative embodiments of the method are substantially similar to the steps described with reference to Figures 3a, 3b, 3c and 3d and therefore will not be repeated.

[0046] In a second alternative embodiment of the method for manufacturing a photovoltaic cell 1, in a fourth step shown in FIG. 5d, a chemical etching is performed to etch both the conductive layer 8, such as the metal layer 8, and the amorphous silicon layer 6, obtaining an opening given the reference number 12′ to define the openwork portion.

[0047] Similarly for the third alternative embodiment of the method for manufacturing a photovoltaic cell 1, in a fourth step shown in FIG. 6d, chemical etching is performed to etch both the conductive layer 8, such as a metal layer 8, and the amorphous silicon layer 6 together with the first front layer 4 on top of the base layer, which may be glass 2 of the portable object.

[0048] If fretwork is used to make the photovoltaic cells semi-transparent, the cutout may be chosen between 75 and 95%; it is difficult to design since a maximum PV coverage of 25% would be too visible and a minimum of 5% would result in too low cell power.

[0049] However, as indicated at the beginning of the detailed description, the method for manufacturing a photovoltaic cell may start directly from a first front collector layer 4 constituting a base layer, from which other layers are arranged in turn on one side of this first front collector layer 4. This first front collector layer 4 may advantageously consist of a layer of zinc oxide ZnO or a first layer of aluminium doped zinc oxide (ZnO:Al or AZO).

[0050] In the above case, the manufactured photovoltaic cell 1 is not combined with the glass of the portable object or placed directly on the dial of the portable object. With a photovoltaic cell 1 consisting of only three layers as described above, it is necessary to make it possible to connect the connection terminals of the positive and negative peripheral buses to an electronic module that is typically located under the dial of the portable object in order to manage the signals received by and through said connection terminals of the positive and negative peripheral buses.

[0051] It should be noted that the connection of these positive and negative peripheral bus connection terminals with the electronic module of the portable object can be made using flexible connections of the FPC (flexible printed circuit) type bonded to ACF (anisotropic conductive film), or spring bar connectors also called pogos, or zebra type connectors (elastic blocks containing a number of regularly spaced conductive areas). However, the connection of the photovoltaic cell with 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 buses to optimize the efficiency of such photovoltaic cells. In this case, thanks to the specific arrangement of the positive and negative peripheral buses, the potential drop in the connection with the low conductive TCO layer is reduced compared to the photovoltaic cells of the prior art.

[0052] Numerous other configurations of photovoltaic cells may be envisioned 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 of a portable object or on a dial, said photovoltaic cell (1) comprising a first transparent conductive (TCO) layer constituting a front collector (4), an amorphous silicon layer (6) on said first front collector layer (4), a conductive layer (8) constituting a rear collector on said amorphous silicon layer (6), and an electrical connection from said conductive layer (8) to said first front collector layer (4) made to pass through said amorphous silicon layer (6), Features: the electrical connection from the second conductive layer (8) to the first front collector layer (4) is made to pass through the amorphous silicon layer (6) at the periphery of the photovoltaic cell; the conductive layer (8) includes a positive peripheral bus (8') and a negative peripheral bus, the positive peripheral bus (8') being connected at one end of the positive peripheral bus to the first front collector layer (4) and at least one positive connection terminal (8'a, 8'b), and the negative peripheral bus being connected to a negative connection terminal; the positive peripheral bus and the negative peripheral bus are asymmetric with respect to one another, with the positive peripheral bus having a greater length than the negative peripheral bus; Photovoltaic cell (1).

2. the thickness and width of said positive peripheral bus is substantially the same as the thickness and width of said negative peripheral bus; The length of the positive peripheral bus is at least 10 times greater than the length of the negative peripheral bus.

2. Photovoltaic cell (1) according to claim 1, characterized in that

3. 2. Photovoltaic cell (1) according to claim 1, characterized in that the electrical connection between the conductive layer (8) and the TCO first layer (4) is made penetrating the amorphous silicon layer (6) over the entire length of the positive peripheral bus which is manufactured in a second conductive layer (8) which is a second metal layer.

4. 4. Photovoltaic cell (1) according to claim 3, characterized in that the metal layer is a layer of aluminium.

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

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

7. 2. The photovoltaic cell (1) according to claim 1, characterized in that various successive layers from the TCO first front layer (4) are manufactured on the inner surface of the glass of the portable object (2) to form a single segment photovoltaic cell assembly with the glass of the portable object (2) forming part of the photovoltaic cell.

8. 2. The photovoltaic cell (1) according to claim 1, characterized in that the conductive layer (8) is a metal layer containing an openwork portion which makes the photovoltaic cell translucent in its central portion connected to the negative terminal of the negative peripheral bus.

9. A method for manufacturing a photovoltaic cell (1) according to claim 1, comprising the steps of: Depositing an amorphous silicon layer (6) on the TCO first layer (4); creating an opening (12) through said amorphous silicon layer (6) to give access to said TCO first layer (4); depositing a conductive layer (8) on said amorphous silicon layer (6) with a portion of said conductive layer (8) in contact with said TCO first layer (4); Including, The method comprises: making said openings through said amorphous silicon layer (6) located in the peripheral area of ​​said photovoltaic cell (1); separating said conductive layer (8) by producing openings (12') in said conductive layer so as to penetrate said conductive layer (8) on the one hand in contact with said TCO front layer (4) to produce said positive peripheral bus (8') and on the other hand so that said metal layer is connected to the parts of said negative peripheral bus connected to the negative terminal (8) of said photovoltaic cell; A method comprising:

10. The method according to claim 9, wherein the conductive layer (8) is a metal layer, such as a layer of aluminium.

11. 10. The method according to claim 9, wherein an openwork portion is produced in a central portion of the metal layer connected to the negative connection terminal.

12. 10. Method according to claim 9, characterized in that all the steps of manufacturing the photovoltaic cell (1) are carried out on a base layer, the glass (2) of the portable object which forms part of the photovoltaic cell.

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