Photovoltaic cell having a specific arrangement of energy collectors and method for manufacturing 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 specific arrangement of collectors that collect energy in the form of current, and a method for manufacturing such a photovoltaic cell.

[0002] That is, the present invention is configured to optimize 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 conforms to the shape of the portable object that receives it. Typically, this photovoltaic cell can be a cylindrical battery arranged on the inner surface of the glass of the portable object that receives it or on the surface of the visible dial from the outside of the portable object.

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

[0005] In this configuration, positive charge carriers drift toward the front collector. At the front collector, the positive charge carriers are neutralized by electrons from the external electrical circuit. Negative charge carriers drift toward the rear collector. At the rear collector, the negative charge carriers supply electrons to the external circuit, forming a negative charge current between the rear and front collectors. By convention, this refers to a (positive) current flowing between the positive and negative electrodes, so in the configuration just described, the charge current is negative.

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

[0007] In the case of a uniform photovoltaic cell, referred to as a single-segment battery, as shown in Figure 1, the current lines can be seen to follow approximately linear and parallel paths between the two peripheral buses. It should be noted that, according to current transparent conductive layer techniques 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 of the battery to form the rear current collector.

[0008] This difference in layer resistance results in a significantly higher potential gradient across the front collector than across the rear collector when current flows, along with power loss that increases as the current value increases. [Overview of the project]

[0009] Accordingly, the present invention proposes a photovoltaic cell having a specific arrangement of current collectors or peripheral buses that substantially reduces the voltage drop within the front collector. This voltage drop is induced by the current generated by the absorption layer after light capture.

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

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

[0012] To provide an electrical contact on only one side of a photovoltaic cell, typically, a portion of the rear collector is separated by chemical etching or other means so that it can be used as a positive terminal. This positive terminal is electrically connected to the front collector by a metal bus deposited in a pre-made opening that penetrates a series of thin amorphous silicon layers (absorbers). The front collector, which may be formed using a transparent and conductive (TCO) aluminum-doped zinc oxide (ZnO:Al or AZO) layer, has much lower conductivity than the rear collector, which may be a metal layer made of aluminum, for example. This difference in conductivity is about 30 times worse.

[0013] Under these conditions, the present invention provides at least one metal peripheral bus connected to the front collector, the length of 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 voltage drop within the front collector to less than 100 mV. This corresponds to a gain of approximately 50 mV compared to the voltage drop observed in a photovoltaic cell with symmetrical peripheral buses. Since the voltage drop within the front collector can be less than 100 mV, this makes it possible to limit power loss in a photovoltaic cell that generates a voltage not exceeding 600 to 700 mV before processing in the electronic module of a portable object.

[0014] Advantageously, two buses of asymmetrical length may be provided, extending from the connection point of the front collector to a portion of the rear collector, which is preferably an aluminum metal layer on the opposite side. These buses are connected to the front collector on one side and to an aluminum metal layer defining the negative terminal on the other.

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

[0016] Advantageously, each free end of the positive peripheral bus connected to the front collector includes a connecting terminal to further reduce the current flowing through this metal peripheral bus. That is, the two positive terminals linked to this peripheral bus connected to the front collector are intended to be connected in parallel to, for example, an electronic data processing module by a flexible connector. Thus, the value of the current flowing to each end of the metal peripheral bus is 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 present invention further relates to a method for manufacturing a photovoltaic cell as defined in independent claim 9. [Brief explanation of the drawing]

[0018] The purpose, advantages, and features of a photovoltaic cell having a specific arrangement of energy collectors, as well as the purpose, 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]This shows a bottom view of a photovoltaic cell having symmetrical peripheral buses for negative and positive terminals according to prior art. [Figure 2] The bottom view of a photovoltaic cell is shown, which has asymmetrical peripheral buses of different lengths for connecting a front collector to the positive terminal and a rear collector to the negative terminal. These buses consist of metal layers already used to form the rear collector according to the present invention. [Figures 3a-3d] Figures 3a, 3b, 3c, and 3d show cross-sectional views of the four steps of a method for manufacturing a photovoltaic cell in the first embodiment. In the central reading area of ​​the photovoltaic cell, an area of ​​conductive layer without perforations is maintained, but the positive area is clearly separated from the negative area. [Figure 4] Figure 3d shows a bottom view of a photovoltaic cell having an asymmetrical peripheral bus, i.e., a peripheral bus of different lengths in the negative area, according to a first alternative embodiment of the present invention shown in the cross-sectional view. [Figures 5a-5d] Figures 5a, 5b, 5c, and 5d show cross-sectional views of four steps in a method for manufacturing a photovoltaic cell according to a second alternative embodiment of the photovoltaic cell. [Figures 6a-6d] Figures 6a, 6b, 6c, and 6d show cross-sectional views of four steps in a method for manufacturing a photovoltaic cell according to a third alternative embodiment of the photovoltaic cell. [Modes for carrying out the invention]

[0020] The following description primarily concerns a single-segment photovoltaic cell having a specific arrangement of current collectors. These current collectors include an asymmetrical peripheral bus or collector 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 includes a first front layer called a front collector, which is transparent to ambient light. This front collector can be manufactured 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 a portable object facing the dial, and typically, a p-i-n type sequence (p-doped, intrinsic i, n-doped) of an amorphous silicon (a-Si) thin layer called an absorber is deposited thereon. The absorber generates positive charge carriers (holes) and negative charge carriers (electrons) under light irradiation. The structure typically ends with a second conductive layer, which can be a metal layer called a rear collector (made from, for example, aluminum or a combination of other metals).

[0022] The single-segment photovoltaic cell may include a base layer formed thereon. Either one of the two sides of the glass of the portable object or a part of the dial of the portable object can also function as the base layer of the photovoltaic cell. In the remaining part of the description, it is preferred to manufacture a complete photovoltaic cell on the inner surface of the glass.

[0023] It should be noted in comparison with Figure 1 of the prior art that Figure 2 shows a relatively summarized embodiment with 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 photovoltaic cell to which it is connected.

[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 Figure ②, thus reducing the potential difference between the maximum value at the center and the minimum value at the periphery.

[0025] The rear collector connected to the defined negative terminal 8 is composed of a metal layer with low electrical resistance. Thereby, despite the unfavorable geometry, the potential difference between the terminal 8 and its diametrical end is limited to a negligible value compared to the front collector.

[0026] The photovoltaic cell 1 is typically cylindrical in shape. This portion of the cylinder may be intended to be fixed below the glass of a portable object or above the dial of a portable object. The portable object may be, for example, a clock.

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

[0028] The positive peripheral bus 8' is connected to a front collector, not shown in Figure 2, over its maximum length, preferably over its entire length. This means that this positive peripheral bus terminates at a first positive terminal 8'a, and the opposite end terminates at a second positive terminal 8'b, and these terminals are subsequently 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 subsequently connected to an electronic module via a specific connector. These two positive terminals 8'a and 8'b of the positive peripheral bus 8' allow for a 3 / 4 reduction in the voltage drop across the positive peripheral bus. This is achieved by arranging the two sectors of this bus in parallel and subsequently connecting them to the electronic module, dividing the collected current by 2 and the covered distance by 2 on the other.

[0029] Figures 3a, 3b, 3c, and 3d illustrate various steps of a method for manufacturing a photovoltaic cell according to the first embodiment. As seen in the first Figure 3a, there is a base layer 2 which is a glass layer. This forms part of the actual photovoltaic cell in this case. However, multiple layers may be used, with one layer on top of the other layers serving as the base layer 2, and these layers consist of at least one glass layer with one or more layers of transparent material placed above or below it, or at the end of the method, a sapphire layer may be deposited on one or more glass layers.

[0030] More typically, the photovoltaic cell 1 includes a first front collector layer 4 as a base layer, which is defined as a front collector at the end of the manufacturing process. A pin-type sequence (p-doped, intrinsically i, n-doped) of amorphous silicon (a-Si) thin layers, referred to as an absorber or defined as an amorphous silicon layer 6, is deposited on the first front collector layer, and a second conductive layer 8, preferably a metallic layer such as an aluminum layer, is added to this amorphous silicon layer 6.

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

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

[0033] It should also be noted that the photovoltaic cell 1 may also be mounted or fixed to the dial of a portable object. However, in this case, the front collector layer 8 directly serves as the base layer, because this front collector layer 8 is mounted or fixed to the dial of the portable object on the side of the second conductive layer (rear collector), which may be a metal layer, at the end of the manufacturing method of the single-segment photovoltaic cell 1. The first layer of this front collector may, 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 for the portable object 2, and various subsequent steps are performed on the inner surface of the glass 2 of the portable object. The glass layer 2 is shown as the base layer on which various other layers of the single-segment photovoltaic cell 1 are deposited.

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

[0036] The second step of the method shown in Figure 3b is to create an opening 12, typically at the periphery of the photovoltaic cell 1. This opening 12 passes through a thin layer of amorphous silicon (a-Si) with a pin (p-doped, i-inherent, n-doped) sequence defined as the amorphous silicon layer 6, providing access to the first front layer. Each opening 12 created to connect the first front collector layer is made using a laser or other etching technique used in microelectronics. Next, in the third step of the method for manufacturing the photovoltaic cell 1 shown in Figure 3c, a second conductive layer 8 is deposited on top of the amorphous silicon layer 6. This second conductive layer 8 is preferably a metallic layer, such as an aluminum layer. This metallic layer is preferably made of aluminum and passes through the opening 12 created in the method step shown in Figure 3b to contact the first front layer 4.

[0037] Finally, the final step of the manufacturing method shown in Figure 3d consists of separating a second conductive layer 8, which may be a metal layer made of, for example, aluminum 8, so that it contacts the TCO front layer 4 on the one hand, and a metal layer connected to multiple portions of at least one negative terminal of the photovoltaic cell on the other hand. For this purpose, an opening 12' is made in the conductive layer so as to penetrate the conductive layer 8, which may be an aluminum layer 8. This opening 12' is formed so as to separate, for example, an aluminum metal layer 8' connected to the first front layer 4 from an aluminum metal layer 8 connected to the negative terminal of the photovoltaic cell 1.

[0038] In the final step of this first alternative embodiment of the photovoltaic cell 1 in Figure 3d, a light beam or light 10 can be captured by the photovoltaic cell 1. As will be described below, the photovoltaic cell 1 is intended to be connected to an electronic module, typically located beneath the dial of a portable object, to convert light into electrical energy.

[0039] Figure 4 shows a bottom view at the end of the manufacturing process, illustrating that a second metal layer, for example made from aluminum, is separated and connected to the front collector layer on one end and to the negative terminal of the photovoltaic cell 1 on the other. In Figure 4, the asymmetrical peripheral bus of the present invention, namely the positive peripheral bus connected to the front collector layer and the negative peripheral bus connected to the negative terminal of the photovoltaic cell, are clearly shown.

[0040] One or more openings made in the second conductive layer 8, such as the aluminum layer, are permitted to create a positive peripheral bus 8' intended for subsequent connection to an electronic module beneath the dial of the portable object. By making these openings, the amorphous silicon layer 6 beneath this conductive layer (i.e., the aluminum layer 8) can be seen.

[0041] The positive peripheral buses from the connection to the first front collector layer are each terminated at a first positive terminal 8'a on the first side and at a second positive terminal 8'b on the second side. The two peripheral bus sectors together form a total arc defined over at least 330°. The negative peripheral bus of the aluminum layer is represented only by a 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 demonstrates the asymmetry of the positive and negative peripheral buses desired by the present invention.

[0042] The two positive peripheral bus sectors 8' together are approximately 10 times longer than the negative peripheral bus 8'. This provides the advantage of reducing the voltage drop described above, especially at high light levels that generate strong currents.

[0043] Furthermore, in this first alternative embodiment, the negative terminal 8 is directly connected to the rest of the metal layer 8. This metal layer 8 has no openwork portion and is surrounded by two positive peripheral bus sectors 8'.

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

[0045] It should be noted that all steps in the method for producing these second and third alternative embodiments of the method are substantially the same as 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 the photovoltaic cell 1, in the fourth step shown in Figure 5d, chemical etching is performed to etch both the conductive layer 8, such as the metal layer 8, and the amorphous silicon layer 6, thereby obtaining an opening given reference numeral 12' and defining the filigree portion.

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

[0048] When a perforated portion is used to make a photovoltaic cell semi-transparent, the cutout can be selected between 75% and 95%. In other words, a maximum PV coverage of 25% would be too visible, while a minimum of 5% would result in too little battery power, making the design difficult.

[0049] However, as shown at the beginning of the detailed description, the method for manufacturing a photovoltaic cell may begin directly with a first front collector layer 4 that constitutes the base layer. From this base layer, the other layers are arranged sequentially from one side of this first front collector layer 4. This first front collector layer 4 can advantageously consist of a layer of zinc oxide ZnO or a first layer of aluminum-doped zinc oxide (ZnO:Al or AZO).

[0050] In the above case, the manufactured photovoltaic cell 1 is neither bonded to the glass of the portable object nor placed directly on the dial of the portable object. With the photovoltaic cell 1 consisting only of the three layers described above, it is necessary to enable the connection terminals of the positive and negative peripheral buses to be connected to a typical electronic module located beneath the dial of the portable object, which then manages the signals received through these connection terminals by the positive and negative peripheral buses.

[0051] It should be noted that these positive and negative peripheral bus connection terminals can be connected to the electronic module of the portable object using flexible connections of the FPC (flexible printed circuit) type bonded to the ACF (anisotropic conductive film), or spring bar connectors also known as pogos, or zebra connectors (elastic blocks containing multiple regularly spaced conductive areas). However, since the present invention is based primarily on the difference in length between the positive and negative peripheral buses in order to optimize the efficiency of such a photovoltaic cell, the connection between the photovoltaic cell and the electronic module of the portable object will not be described in further detail. In this case, thanks to the specific arrangement of the positive and negative peripheral buses, the potential drop at the connection to the low-conductivity TCO layer is reduced compared to prior art photovoltaic cells.

[0052] Without departing from the scope of the present invention as defined by the claims, those skilled in the art can conceive of various other forms of photovoltaic cells.

Claims

1. A photovoltaic cell (1) intended to be arranged on the inner surface of the transparent glass of a portable object (2) or on the dial, wherein the photovoltaic cell (1) is cylindrical and includes a first transparent conductive (TCO) layer (4) constituting a front collector, an amorphous silicon layer (6) on the first TCO layer (4), a second conductive layer (8) constituting a rear collector on the amorphous silicon layer (6), and an electrical connection portion from the second conductive layer (8) to the first TCO layer (4) made to penetrate the amorphous silicon layer (6). The features are, The electrical connection portion from the second conductive layer (8) to the first TCO layer (4) is made to penetrate the amorphous silicon layer (6) at the circular periphery of the photovoltaic cell (1), The second conductive layer (8) includes a positive peripheral bus (8') and a negative peripheral bus along the circular periphery, the positive peripheral bus (8') is connected at one end to the first TCO layer (4) and two positive connection terminals (8'a, 8'b), the negative peripheral bus is connected to a negative connection terminal, the positive peripheral bus (8') terminates on the first side at the first positive connection terminal (8'a) and on the second opposite side at the second positive connection terminal (8'b), Along the circular periphery, the positive peripheral bus (8') has a larger arc length than the negative peripheral bus, The thickness and width of the positive peripheral bus (8') are substantially the same as the thickness and width of the negative peripheral bus, The arc length of the positive peripheral bus (8') is at least 10 times longer than the arc length of the negative peripheral bus. A photovoltaic cell (1) located here.

2. The photovoltaic cell (1) according to claim 1, characterized in that the electrical connection between the second conductive layer (8) and the first TCO layer (4) penetrates the amorphous silicon layer (6) over the entire length of the positive peripheral bus (8').

3. The photovoltaic cell (1) according to claim 2, characterized in that the second conductive layer (8) is a layer of aluminum.

4. A photovoltaic cell (1) intended to be arranged on the inner surface of the transparent glass of a portable object (2) or on the dial, wherein the photovoltaic cell (1) is cylindrical, and the photovoltaic cell (1) includes a first transparent conductive (TCO) layer (4) constituting a front collector, an amorphous silicon layer (6) on the first TCO layer (4), a second conductive layer (8) constituting a rear collector on the amorphous silicon layer (6), and an electrical connection portion from the second conductive layer (8) to the first TCO layer (4) made to penetrate the amorphous silicon layer (6), The features are, The electrical connection portion from the second conductive layer (8) to the first TCO layer (4) is made to penetrate the amorphous silicon layer (6) at the circular periphery of the photovoltaic cell (1), The second conductive layer (8) includes a positive peripheral bus (8') and a negative peripheral bus along the circular periphery, the positive peripheral bus (8') is connected at one end to the first TCO layer (4) and two positive connection terminals (8'a, 8'b), the negative peripheral bus is connected to a negative connection terminal, the positive peripheral bus (8') terminates on the first side at the first positive connection terminal (8'a) and on the second opposite side at the second positive connection terminal (8'b), Along the circular periphery, the positive peripheral bus (8') has a larger arc length than the negative peripheral bus, The thickness and width of the positive peripheral bus (8') are substantially the same as the thickness and width of the negative peripheral bus, The positive peripheral bus (8') has the electrical connection portion with the first TCO layer (4) along its entire length, forming a total arc of 330°. A photovoltaic cell (1) located here.

5. The photovoltaic cell (1) according to claim 4, characterized in that the negative peripheral bus including the negative connection terminal follows an arc of less than 30° having the first positive connection terminal (8'a) of the positive peripheral bus (8') and the second positive connection terminal (8'b) of the positive peripheral bus (8') on each side.

6. A photovoltaic cell (1) intended to be arranged on the inner surface of the transparent glass of a portable object (2) or on the dial, wherein the photovoltaic cell (1) is cylindrical, and the photovoltaic cell (1) includes a first transparent conductive (TCO) layer (4) constituting a front collector, an amorphous silicon layer (6) on the first TCO layer (4), a second conductive layer (8) constituting a rear collector on the amorphous silicon layer (6), and an electrical connection portion from the second conductive layer (8) to the first TCO layer (4) made to penetrate the amorphous silicon layer (6), The features are, The electrical connection portion from the second conductive layer (8) to the first TCO layer (4) is made to penetrate the amorphous silicon layer (6) at the circular periphery of the photovoltaic cell (1), The second conductive layer (8) includes a positive peripheral bus (8') and a negative peripheral bus along the circular periphery, the positive peripheral bus (8') is connected at one end to the first TCO layer (4) and two positive connection terminals (8'a, 8'b), the negative peripheral bus is connected to a negative connection terminal, the positive peripheral bus (8') terminates on the first side at the first positive connection terminal (8'a) and on the second opposite side at the second positive connection terminal (8'b), Along the circular periphery, the positive peripheral bus (8') has a larger arc length than the negative peripheral bus, The thickness and width of the positive peripheral bus (8') are substantially the same as the thickness and width of the negative peripheral bus, The positive peripheral bus (8') has the electrical connection portion with the first TCO layer (4) along its entire length, forming a 350° total arc. A photovoltaic cell (1) located here.

7. The photovoltaic cell (1) according to claim 6, characterized in that the negative peripheral bus including the negative connection terminal follows an arc of less than 10° having the first positive connection terminal (8'a) of the positive peripheral bus (8') and the second positive connection terminal (8'b) of the positive peripheral bus (8') on each side.

8. The photovoltaic battery (1) according to claim 1, characterized in that various continuous layers from the first TCO layer (4) are provided on the inner surface of the transparent glass of the portable object (2) to form a single-segment photovoltaic battery assembly with the transparent glass of the portable object (2) which forms part of the photovoltaic battery (1).

9. The photovoltaic cell (1) according to claim 1, characterized in that the second conductive layer (8) is a metal layer that includes a perforated portion that makes the photovoltaic cell semi-transparent in the central portion connected to the negative connection terminal of the negative peripheral bus.

10. A method for manufacturing a photovoltaic cell (1) according to any one of claims 1 to 9, The steps include depositing the amorphous silicon layer (6) on the first TCO layer (4), The steps include creating an opening (12) through the amorphous silicon layer (6) to provide access to the first TCO layer (4), The steps include depositing the second conductive layer (8) on the amorphous silicon layer (6) such that a portion of the second conductive layer (8) is in contact with the first TCO layer (4), and Includes, The aforementioned method, The steps include creating the opening (12) so as to penetrate the amorphous silicon layer (6) located in the peripheral area of ​​the photovoltaic cell (1), The steps of separating the second conductive layer (8) by manufacturing an opening (12') in the second conductive layer (8) so as to penetrate the second conductive layer (8), on the one hand, so as to contact the first TCO layer (4) and manufacture the positive peripheral bus (8'), and on the other hand, so as to connect the second conductive layer (8) to multiple portions of the negative peripheral bus that are connected to the negative connection terminal of the photovoltaic cell (1), and A method characterized by the following.

11. The method according to claim 10, wherein the second conductive layer (8) is a metal layer including a layer of aluminum.

12. The method according to claim 11, wherein a filigree portion is manufactured in the central portion of the metal layer connected to the negative connection terminal.

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

Images