Device and method for detecting photovoltaic cell failure

Abstract

Device and method for detecting failure of a photovoltaic cell. This description relates to a photovoltaic module (Mod) comprising photovoltaic (PV) cells and comprising, for each photovoltaic cell, an electronic circuit (10) connected in parallel with the photovoltaic (PV) cell and comprising at least one light-emitting diode (LED). Figure for the abstract: Fig. 1

Description

Title of the invention: Device and method for detecting failure in a photovoltaic cell. Technical field

[0001] The present description relates in general to a device and a method for detecting a failure of a photovoltaic cell. Previous technique

[0002] A photovoltaic module comprises several photovoltaic cells connected in series. The performance of a photovoltaic cell can decrease over time, particularly due to the formation of cracks or breaks. It may then be necessary to replace the faulty photovoltaic cell in the photovoltaic module.

[0003] There are monitoring devices for a photovoltaic module that can detect a decrease in the module's performance. However, such devices do not allow for the simple and immediate determination of which photovoltaic cell in the photovoltaic module is faulty. Summary of the invention

[0004] An embodiment overcomes all or part of the drawbacks of known devices and methods for detecting failure of a photovoltaic cell of a photovoltaic module.

[0005] An object of an embodiment is that the fault detection method can be implemented at the operating site of the photovoltaic module.

[0006] One embodiment provides for a photovoltaic module comprising photovoltaic cells and comprising, for each photovoltaic cell, an electronic circuit connected in parallel with the photovoltaic cell and comprising at least one light-emitting diode.

[0007] According to one embodiment, each electronic circuit includes a resistor in series with the light-emitting diode.

[0008] According to one embodiment, for each electronic circuit, the assembly comprising the resistor in series with the light-emitting diode is connected in parallel with the photovoltaic cell to which the electronic circuit is connected.

[0009] According to one embodiment, each photovoltaic cell comprises a first cell terminal and a second cell terminal, the photovoltaic cell being configured to supply an electric current flowing from the second cell terminal to the first cell terminal when it receives light, and, for each electronic circuit, the anode of the light-emitting diode of the electronic circuit is coupled to the second cell terminal of the photovoltaic cell to which the electronic circuit is connected and the cathode of the light-emitting diode of the electronic circuit is coupled to the first cell terminal of the photovoltaic cell to which the electronic circuit is connected.

[0010] According to one embodiment, each photovoltaic cell comprises a silicon plate having first and second opposite faces. At least a portion of the electronic circuits are located along the photovoltaic cells, or between the photovoltaic cells, or on the first faces of the silicon plates, or on the second faces of the silicon plates.

[0011] According to one embodiment, each electronic circuit comprises at least two light-emitting diodes.

[0012] One embodiment also provides a system comprising a photovoltaic module as defined above, in which the photovoltaic module includes a first module terminal and a second module terminal, the photovoltaic module being configured to provide an electric current flowing from the second module terminal to the first module terminal when the photovoltaic cells receive light, the system further comprising a voltage generator configured to apply a negative voltage between the first module terminal and the second module terminal.

[0013] According to one embodiment, the voltage generator is a device separate from the photovoltaic module configured to be manually connected to the photovoltaic module.

[0014] An embodiment also provides a method for detecting photovoltaic cell failures in a photovoltaic module as defined above, the photovoltaic module comprising a first module terminal and a second module terminal, the method comprising the following steps: - apply a negative voltage between the first module terminal and the second module terminal; and - determine if the amount of light emitted by at least one of the light-emitting diodes is less than the amount of light emitted by other light-emitting diodes among the light-emitting diodes.

[0015] According to one embodiment, the negative voltage applied between the first module terminal and the second module terminal is variable.

[0016] According to one embodiment, the process further comprises the following steps, in order: a) measure a first leakage current of a defect-free photovoltaic cell identical to the photovoltaic cells of the photovoltaic module; b) measure the electrical power supplied by the photovoltaic cell under illumination; c) create a defect in the photovoltaic cell and measure the electrical power supplied by the photovoltaic cell with the defect under said illumination; d) repeat step c) until the measured electrical power falls below a threshold; e) measure a second leakage current from the defective photovoltaic cell; and f) determine the characteristics of the light-emitting diode of each electronic circuit from the first leakage current and the second leakage current. Brief description of the drawings

[0017] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments, given by way of non-limiting example, in relation to the accompanying figures, among which:

[0018] [Fig.1] is a partial electrical diagram of an embodiment of a photovoltaic module comprising a photovoltaic cell failure detection device;

[0019] [Fig.2] illustrates an equivalent electrical diagram of the photovoltaic module shown in [Fig.1];

[0020] [Fig.3] represents evolution curves of leakage currents of photovoltaic cells of different technologies;

[0021] [Fig.4] represents the current-voltage characteristic of a light-emitting diode;

[0022] [Fig.5] represents a curve of evolution of the relative luminous intensity of the radiation emitted by a light-emitting diode as a function of the current through the light-emitting diode;

[0023] Fig. 6 and Fig. 7 illustrate an embodiment of a method for detecting the failure of each photovoltaic cell of a photovoltaic module;

[0024] [Fig.8] is a figure analogous to [Fig.7] and illustrates another embodiment of a method for detecting failure of each photovoltaic cell of a photovoltaic module;

[0025] [Fig.9] is a block diagram of an embodiment of a method for determining the properties of a light-emitting diode for a fault detection device;

[0026] [Fig. 10] is a partial electrical diagram of another embodiment of a photovoltaic module comprising a photovoltaic cell failure detection device;

[0027] [Fig.1 1] illustrates an equivalent electrical diagram of the photovoltaic module shown in [Fig. 10];

[0028] [Fig.12], [Fig.13], and [Fig.14] each represent the evolution curves of the leakage current of a photovoltaic cell as a function of a negative voltage across its terminals for several photovoltaic cell technologies;

[0029] Figures 15, 16, 17, and 18 illustrate embodiments of photovoltaic modules showing several arrangements of the photovoltaic cell failure detection device; and

[0030] [Fig. 19] and [Fig. 20] are partial electrical diagrams of other embodiments of a photovoltaic module comprising a photovoltaic cell failure detection device. Description of the implementation methods

[0031] The same elements have been designated by the same reference numerals in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same reference numerals and may have identical structural, dimensional and material properties.

[0032] For the sake of clarity, only the steps and elements necessary for understanding the described embodiments have been shown and are detailed. In particular, the internal structure and operation of a photovoltaic cell and a photovoltaic module are known to those skilled in the art and are not described.

[0033] Unless otherwise specified, when referring to two elements connected together, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") together, this means that these two elements can be connected or linked through one or more other elements.

[0034] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "superior", "inferior", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made, unless otherwise specified, to the orientation of the figures or to a photovoltaic module in a normal operating position.

[0035] Unless otherwise specified, the expressions "approximately", "roughly", and "on the order of" mean to within 10% or 10°, preferably to within 5% or 5°.

[0036] Figure 1 is a partial electrical diagram of an embodiment of a photovoltaic module Mod, also called a photovoltaic panel. The photovoltaic module Mod comprises photovoltaic PV cells connected in series. between a positive terminal M+ of the photovoltaic module Mod and a negative terminal M- of the photovoltaic module Mod. The voltage UM corresponds to the voltage between the positive terminal M+ and the negative terminal M-, that is to say the difference between the potential at the positive terminal M+ and the potential at the negative terminal M-.

[0037] By way of example, in [Fig. 1], the photovoltaic module Mod is shown comprising three photovoltaic PV cells. Generally, the photovoltaic module Mod can comprise from 1 to 144 photovoltaic PV cells. Each photovoltaic PV cell comprises a positive cell terminal C+ and a negative cell terminal C-. This means that when the photovoltaic PV cell receives light, it supplies a current that flows from the positive cell terminal C+ to the negative cell terminal C-. The voltage UC corresponds, for each photovoltaic PV cell, to the voltage between the positive cell terminal C+ and the negative cell terminal C-, that is, to the difference between the potential of the positive cell terminal C+ and the potential of the negative cell terminal C-.

[0038] For the PV photovoltaic cell connected to the positive terminal M+ of the photovoltaic module Mod, the positive terminal C+ of the PV photovoltaic cell is connected to the positive terminal M+ of the photovoltaic module Mod. For the PV photovoltaic cell connected to the negative terminal M- of the photovoltaic module Mod, the negative terminal C- of the PV photovoltaic cell is connected to the negative terminal M- of the photovoltaic module Mod. For each third PV photovoltaic cell connected between the first and second PV photovoltaic cells, the positive terminal C+ of the third PV photovoltaic cell is connected to the negative terminal C- of the first PV photovoltaic cell, and the negative terminal C- of the third PV photovoltaic cell is connected to the positive terminal C+ of the second PV photovoltaic cell.

[0039] The photovoltaic module Mod can include, for each PV photovoltaic cell, an electrical load 12, for example an electronic circuit, connected in parallel with the PV photovoltaic cell.

[0040] In this embodiment, the photovoltaic module Mod includes a status indicator device 5 for the photovoltaic PV cells. The status indicator device 5 for the photovoltaic PV cells includes a status indicator circuit 10 for each photovoltaic PV cell. The status indicator circuit 10 is configured to provide a visual signal indicating the operating state of the photovoltaic cell PC to which it is associated. In one embodiment, each status indicator circuit 10 is connected in parallel with the photovoltaic PV cell to which it is associated. In one embodiment, each status indicator circuit 10 includes a light-emitting diode (LED). V, pn is denoted as the voltage between the anode and cathode of the LED. In one embodiment of In this implementation, each status indicator circuit 10 comprises only a light-emitting diode (LED) connected in parallel with the photovoltaic (PV) cell to which the status indicator circuit 10 is associated. The voltage V,m is then equal to the negative of the voltage UC. The anode of the LED is connected to the negative terminal C- of the PV cell, and the cathode of the LED is connected to the positive terminal C+ of the PV cell.

[0041] Figure 2 illustrates an equivalent electrical circuit of the photovoltaic module Mod shown in Figure 1. Each PV photovoltaic cell is equivalent to an electrical circuit comprising a current source 14, a diode 16, a first resistor Rsh, and a second resistor Rs. The current source 14, the first resistor Rsh, and the diode 16 are connected in parallel. The second resistor Rs is connected in series between the positive cell terminal C+ of the PV photovoltaic cell and the anode of the diode 16. The cathode of the light-emitting diode LED is connected to the negative cell terminal C- of the PV photovoltaic cell. The current source 14 supplies a current that flows from the negative cell terminal C- to the positive cell terminal C+ when the PV photovoltaic cell is illuminated.

[0042] Generally, a photovoltaic installation can include one photovoltaic module, two photovoltaic modules, or more than two photovoltaic modules connected to each other in series and / or in parallel.

[0043] During operation, when the Mod photovoltaic module receives light, a current flows from the negative terminal M- to the positive terminal M+, and the voltage UM between the positive terminal M+ and the negative terminal M- is positive. Each LED is then reverse-biased and therefore blocked. The presence of the LEDs thus does not significantly alter the normal operation of the Mod photovoltaic module.

[0044] The resistance values ​​Rs and Rsh of each PV photovoltaic cell depend, in particular, on the health of the PV photovoltaic cell. Specifically, when the PV photovoltaic cell deteriorates, the resistance Rsh decreases and the resistance Rs increases. In one embodiment, the resistances Rs of the defect-free PV photovoltaic cells of the photovoltaic module Mod are substantially equal. In another embodiment, the resistances Rsh of the defect-free PV photovoltaic cells of the photovoltaic module Mod are substantially equal.

[0045] When the photovoltaic PV cell does not receive light, when the voltage UC between the positive terminal of cell C+ and the negative terminal of cell C- is negative, a leakage current Iieak can flow from the negative terminal of cell C- to the positive terminal of cell C+ and a current ILED can flow in the light-emitting diode LED connected to the PV photovoltaic cell from the negative terminal of cell C- to the positive terminal of cell C+

[0046] Figure 3 shows the evolution curves C1, C2, C3, C4, C5, C6 of the leakage current ILeak flowing between the negative terminal C- and the positive terminal C+ of a defect-free photovoltaic PV cell in the absence of illumination, at 25 °C, as a function of the voltage UC when the voltage UC applied between the positive terminal C+ and the negative terminal C- is negative, for different types of photovoltaic cells. The inset at the bottom right corresponds to an enlargement at low voltages UC.

[0047] Figure 4 represents the evolution curve of the current L,fb flowing through the Figure 5 shows the relative luminous intensity (RLI) of the LED as a function of the voltage (UC) across the LED at 25 °C, and Figure 4 shows the relative luminous intensity (RLI) of the radiation emitted by the LED as a function of the current (I,pn) flowing through the LED at 25 °C. Figure 4 shows, as an example, an operating point (PF), i.e., the pair L,fb and Vi,fb, of the LED when the photovoltaic cell (PV), to which the status indicator circuit (10) is connected, is fault-free.

[0048] Figures 6 and 7 illustrate an embodiment of a method for detecting the failure of each PV photovoltaic cell of the photovoltaic module Mod. In Figures 6 and 7, the loads 12 are not shown. Each PV photovoltaic cell is schematically represented in top view by a square with rounded edges, and the rectangles located on either side of each PV photovoltaic cell represent the connection elements of the PV photovoltaic cells.

[0049] The method for detecting the failure of each photovoltaic cell is implemented while the photovoltaic module Mod is placed in a location with no or low illumination. A negative voltage UM is applied between the positive terminal M+ and the negative terminal M- by means of a voltage generator 20 which is connected to the positive terminal M+ and the negative terminal M- of the photovoltaic module Mod. Since the photovoltaic module Mod is placed in a location with no or low illumination and a forced operating point due to the application of the negative voltage UM, the current generator 14, shown in [Fig. 2], of each PV photovoltaic cell supplies a substantially zero current. The diode 16, shown in [Fig. 2], of each PV photovoltaic cell is then reverse-biased and is therefore blocked.

[0050] According to one embodiment, the voltage generator 20 used to apply the negative voltage UM is a device separate from the photovoltaic installation containing The photovoltaic module Mod is temporarily connected by an operator to the positive terminal M+ and the negative terminal M- of the photovoltaic module Mod. According to another embodiment, the voltage generator 20 used to apply the negative voltage UM is part of the photovoltaic installation containing the photovoltaic module Mod. The photovoltaic installation then further includes a switching circuit, not shown, actuable by an operator and configured to connect the voltage generator 20 to the positive terminal M+ and the negative terminal M- of the photovoltaic module Mod for the implementation of the fault detection method and to disconnect the voltage generator 20 from the positive terminal M+ and the negative terminal M- of the photovoltaic module Mod for the normal operation of the photovoltaic module Mod.

[0051] When the voltage generator 20 applies the negative voltage UM between the positive terminal M+ and the negative terminal M- of the photovoltaic module Mod, each LED is forward-biased. For each PV cell, the current Ifb flowing through the LED connected to the PV cell depends on the values ​​of the resistances Rsh and Rs, shown in [Fig. 2], of the PV cell. In one embodiment, the characteristics of the LED are chosen so that, when the PV cell is free of defects, the current Lfb flowing through the LED is sufficient for the LED to emit light. In one embodiment, the LEDs are substantially identical.

[0052] In [Fig.6], all the PV photovoltaic cells are defect-free, so that the intensities of the currents I, ,fb flowing in the LEDs are substantially equal and the quantities of light (flashes 18) emitted by the LEDs are substantially equal.

[0053] In [Fig. 7], by way of example, the photovoltaic PV cell located in the middle of the photovoltaic PV cells exhibits a defect. The resistance Rsh of this photovoltaic PV cell is therefore lower than the resistance Rsh of the other two photovoltaic PV cells. The current Lfb flowing in the LED connected to the photovoltaic PV cell exhibiting a defect is lower than the currents Ifb flowing in the LEDs connected to the other photovoltaic PV cells. The quantity of light emitted by the LED connected to the photovoltaic PV cell exhibiting a defect is therefore less than the quantity of light (flashes 18) emitted by each of the other LEDs.

[0054] In general, the amount of light emitted by each LED connected to a PV photovoltaic cell with a defect is less than the amount of light (flashes 18) emitted by LEDs connected to PV photovoltaic cells without defects.

[0055] According to one embodiment, the decrease in the amount of light emitted by each LED connected to a defective photovoltaic cell is visually detectable by an operator implementing the fault detection method. Through simple visual inspection, the operator can therefore observe which PV photovoltaic cell is defective and may require replacement.

[0056] According to one embodiment, in order for the decrease in the quantity of light emitted by each LED, connected to a photovoltaic cell with a defect, to be visually detectable by an operator, the intensity of the current I,m flowing in the LED and the intensity of the leakage current ILeak flowing in a PV photovoltaic cell without a defect are of the same order of magnitude, which means that the intensity of the current I,m flowing in the LED is between 0.8 times the intensity of the leakage current ILeak flowing in a PV photovoltaic cell without a defect and 1.2 times the intensity of the leakage current ILeak flowing in a PV photovoltaic cell without a defect.Furthermore, the operating point PF, i.e. the pair I,m and V,pn, of the LED connected to the PV photovoltaic cell is chosen so that the amount of light emitted by the LED decreases by at least 30% when the PV photovoltaic cell, to which the LED is connected, is faulty compared to the amount of light emitted by the LED when the PV photovoltaic cell, to which the LED is connected, is without fault.

[0057] Figure 8 is analogous to Figure 7 and illustrates another embodiment of a method for detecting a failure in each photovoltaic PV cell of the photovoltaic module Mod. The method further includes the use of a detection device 30 configured to detect whether the amount of light emitted by each LED is less than the amount of light emitted by an LED connected to a fault-free photovoltaic PV cell. The detection device 30 may include a photodetector. The detection device 30 may be moved in front of each LED. The detection device 30 may include several photodetectors that can be placed simultaneously in front of several LEDs. The decrease in the amount of light emitted by each LED connected to a photovoltaic cell with a defect may not be visually detectable by an operator.

[0058] In the embodiments of a fault detection method described above in relation to [Fig. 6], [Fig. 7], and [Fig. 8], the voltage UM applied by the voltage generator 20 is constant. According to another embodiment, the voltage UM applied by the voltage generator 20 is variable, and for example, varies monotonically between an initial voltage and a final voltage. This embodiment allows, at each step of the voltage UM, the LEDs to be illuminated one after the other or together, but in any case with a controlled and non-blinding brightness, more easily distinguishable for the user. This advantageously allows for better visualization of the luminance contrasts between the LEDs.

[0059] The [Fig.9] is a block diagram of an embodiment of a method for determining the characteristics of the light-emitting diode LED of the state indication circuit 10 connected to the photovoltaic cell PV.

[0060] In step 50, at the beginning of the process, the defect-free photovoltaic PV cell, intended to equip the photovoltaic module Mod, is placed in a location without illumination, and the leakage current ILeak of the photovoltaic PV cell is measured. For this purpose, according to one embodiment, a negative reference voltage UC is applied between the positive terminal C+ and the negative terminal C- of the photovoltaic PV cell, and the current ILeak flowing out of the positive terminal C+ is measured. The defect-free photovoltaic PV cell is further placed in a location with controlled illumination, and the electrical power Pinit supplied by the defect-free photovoltaic PV cell is measured. The process continues in step 51.

[0061] In step 51, a defect is created on the photovoltaic PV cell. For example, an impact is applied to the photovoltaic PV cell. For example, a break is created on the photovoltaic PV cell. The process continues in step 52.

[0062] In step 52, the damaged PV photovoltaic cell is placed in a location with controlled illumination, and the electrical power Pdef supplied by the damaged PV photovoltaic cell is measured. The defect created in step 51 results in a decrease in the efficiency of the damaged PV photovoltaic cell and therefore a decrease in the electrical power Pdef supplied by the damaged PV photovoltaic cell. Furthermore, the decrease in the electrical power Pdef supplied by the damaged PV photovoltaic cell, relative to the electrical power Pinit of the PV photovoltaic cell in the absence of the defect, is determined. The process continues in step 53.

[0063] In step 53, it is determined whether the decrease in electrical power is acceptable, i.e., whether the damaged PV photovoltaic cell can be The process continues to be used, or if the decrease in electrical power is unacceptable, meaning the damaged photovoltaic (PV) cell must be replaced. This can be determined by comparing the decrease in electrical power to a threshold. If the decrease in electrical power is less than the threshold, this means the decrease is acceptable and the damaged PV cell can still be used. If the decrease in electrical power is greater than the threshold, this means the decrease is unacceptable and the damaged PV cell must be replaced. If the decrease in electrical power is acceptable, the process continues to step 51, where an additional defect is created on the PV cell. If the decrease in electrical power is unacceptable, the process continues to step 54.

[0064] In step 54, the damaged PV photovoltaic cell is placed in a location without illumination and the leakage current ILeak of the PV photovoltaic cell is measured for which the reduction in electrical power is not acceptable, for example by applying the negative reference voltage UC as in step 50. The characteristics of the LED adapted to the value of the leakage current ILeak in the absence of a defect measured in step 50 and to the value of the leakage current ILeak measured in step 54 are then determined.

[0065] Figure 10 represents another embodiment of the photovoltaic module Mod. The photovoltaic module Mod shown in Figure 10 comprises all the elements of the photovoltaic module Mod shown in Figure 1, plus the status indicator circuit 10 associated with each PV photovoltaic cell, which further comprises a resistor R,p in series with the LED associated with the PV photovoltaic cell. The assembly comprising the LED and the resistor R,pB is coupled, preferably connected between the C- terminal and the C+ terminal of the PV photovoltaic cell. In one embodiment, the status indicator circuit 10 comprises only the LED and the resistor R,pn. Vrled is denoted by the voltage across the resistor R,Fp oriented such that the sum of the voltage V,pn and the voltage V^pn is equal to the negative of the voltage UC.

[0066] Fig. 11 represents a model of one of the PV photovoltaic cells of the photovoltaic module Mod of Fig. 10 with the associated status indication circuit 10 comprising the light-emitting diode LED and the resistor R, Fp in series.

[0067] In the embodiment described above, in which the current ILeak flowing through the photovoltaic cell PV is of the same order of magnitude as the current I,pn flowing through the light-emitting diode LED, the presence of the resistance Ri p,n facilitates the selection of the light-emitting diode LED. As For example, when the leakage current intensity IL eak is equal to 10 mA and the LED has the characteristic curve shown in [Fig.4] and must be biased at the operating point PF, this means that the voltage V, pd across the LED is equal to 1.8 V. In the case where the voltage UC is equal to -3.6 V, this leads to choosing a resistance R, pp equal to 80 ohms.

[0068] Figure 12 shows logarithmic curves of the I0PERC and I1PERC leakage current intensity ILeak of a photovoltaic PV cell as a function of the voltage -UC. The photovoltaic PV cell is of heterojunction technology, also known as PERC (Passivated Emitter and Rear Cell). The I0PERC curve was obtained with the photovoltaic PV cell in its undamaged state. The I1PERC curve was obtained after the photovoltaic PV cell was damaged by creating a break. Figure 12 shows a sharp increase in the leakage current intensity ILeak after the photovoltaic PV cell was damaged over a wide voltage range.In particular, for -UC of the order of 3.6 V, the intensity of the leakage current ILeak for the photovoltaic PV cell without defect is on the order of 10 mA while the intensity of the leakage current ILeak for the photovoltaic PV cell after deterioration is on the order of 90 mA.

[0069] Figure 13 shows logarithmic curves of the leakage current intensity ILeak of a photovoltaic PV cell as a function of the voltage -UC. The photovoltaic PV cell is of the passivated emitter and back-cell technology, also known as HET (Heterojunction). The I0HET curve was obtained with the photovoltaic PV cell in its free state. The IIHET curve was obtained after the photovoltaic PV cell was damaged by creating a break. Figure 13 shows a sharp increase in the leakage current intensity ILeak during the deterioration of the photovoltaic PV cell over a wide voltage range.In particular, for -UC of the order of 3.6 V, the intensity of the leakage current ILeak for the photovoltaic PV cell without defect is on the order of 2 mA while the intensity of the leakage current ILeak for the photovoltaic PV cell after deterioration is on the order of 20 mA.

[0070] Figure 14 shows the evolution curves I0IBC, I1IBC, I2IBC, I3IBC, I4IBC, and I5IBC of the leakage current intensity ILeak, on a logarithmic scale, of a photovoltaic PV cell as a function of the voltage -UC. The photovoltaic PV cell is of interdigitated back contact technology, also known as IBC (Interdigitated Back Contact). The I0IBC curve was obtained with the photovoltaic PV cell without defects. The I1IBC, I2IBC, I3IBC, I4IBC, and I5IBC curves were obtained after deterioration of the photovoltaic PV cell by formation respectively, one break, two breaks, three breaks, four breaks, and five breaks. Figure 14 shows an increase in the leakage current intensity ILeak during the deterioration of the photovoltaic PV cell, particularly over a voltage range of 0.4 V to 1.8 V. Specifically, for -UC on the order of 1 V, the leakage current intensity ILeak for the defect-free photovoltaic PV cell is on the order of 20 mA, while the leakage current intensity ILeak for the photovoltaic PV cell after deterioration is on the order of 100 mA after five breaks.

[0071] By using commercially available electronic components, the surface area required to manufacture the status indicator circuit 10, comprising the LED and the resistor R,m on a substrate, can be between 1 mm² and 5 mm². This means that the surface area occupied by the status indicator circuit 10 is significantly less than the surface area occupied by the PV photovoltaic cell.

[0072] Figures 15, 16, and 17 illustrate embodiments of photovoltaic modules Mod showing arrangements of PV photovoltaic cells and status indicator circuits 10. By way of example, in Figures 15, 16, and 17, only two PV photovoltaic cells are shown arranged in a row. In the embodiments illustrated in Figures 15, 16, and 17, each PV photovoltaic cell comprises a silicon wafer which, viewed from above, has an oval shape inscribed in a rectangle and has a front face receiving light and a rear face opposite the front face. Furthermore, in Figures 15, 16, and 17, for each PV photovoltaic cell, the status indicator circuit 10 connected to the PV photovoltaic cell is represented by a black disk.

[0073] In the embodiment illustrated in [Fig.15], the status indication circuits 10 are located on the side of the row of PV photovoltaic cells, at a distance from the PV photovoltaic cells.

[0074] In the embodiment illustrated in [Fig.16], for each PV photovoltaic cell, the state indication circuit 10 is located next to the silicon wafer in the rectangle in which the silicon wafer is inscribed in top view.

[0075] In the embodiment illustrated in [Fig.17], for each PV photovoltaic cell, the state indication circuit 10 is located on the silicon plate, either on the front face or on the rear face.

[0076] Figure 18 is a partial, schematic view of the rear face of the semiconductor plate 60 of a PV photovoltaic cell according to IBC technology, on which two interdigitated electrodes 61 and 62 of the PV photovoltaic cell are shown. In one embodiment, the status indicator circuit 10, represented by a black rectangle, is located on the rear face of the semiconductor plate 60 between the electrodes 61 and 62.

[0077] Fig. 19 represents another embodiment of the photovoltaic module Mod. The photovoltaic module Mod shown in Fig. 19 comprises all the elements of the photovoltaic module Mod shown in Fig. 10, the status indication circuit 10 associated with each PV photovoltaic cell including, in addition, an additional LED' in series with the LED and the resistor R,m associated with the PV photovoltaic cell, the assembly including the LED, the additional LED' and the resistor R,pd being coupled, preferably connected, between the C- terminal and the C+ terminal of the PV photovoltaic cell.

[0078] In one embodiment, the LEDs LED and LED' are sufficiently far apart to be visually distinguishable by an observer. The LEDs LED and LED' then form a two-point indicator light. The characteristics of the LEDs LED and LED' may differ so that the variation in the amount of light emitted by LED differs from the variation in the amount of light emitted by LED' as a function of the health status of the associated photovoltaic PV cell. This advantageously allows for a more precise assessment of the health status of the photovoltaic PV cell. In one embodiment, each electronic circuit 10 may include more than two LEDs to obtain a multi-point indicator light.

[0079] Fig. 20 represents another embodiment of the photovoltaic module Mod. The photovoltaic module Mod shown in Fig. 20 comprises all the elements of the photovoltaic module Mod shown in Fig. 1, the status indication circuit 10 associated with each PV photovoltaic cell including at least the LED and other electronic components, not shown, for example transistors.

[0080] According to one embodiment, each electronic circuit 10 may include more than two light-emitting diodes arranged sufficiently close to each other so that an observer perceives only a single beam of light. In particular, each electronic circuit 10 may include an RGB light-emitting diode, which may comprise three LEDs, for example, a first LED emitting red light, a second LED emitting green light, and a third LED emitting blue light. The status indicator circuit 10 may further include a control circuit for the RGB LED so that the color of the light emitted by the RGB LED varies according to the leakage current of the associated photovoltaic cell (PV).

[0081] Various embodiments and variations have been described. A person skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will become apparent to a person skilled in the art.

[0082] Finally, the practical implementation of the embodiments and variants described is within the reach of a person skilled in the art, based on the functional indications given above.

Claims

Demands

1. Photovoltaic module (Mod) comprising photovoltaic (PV) cells and comprising, for each photovoltaic cell, an electronic circuit (10) connected in parallel with the photovoltaic (PV) cell and comprising at least one light-emitting diode (LED).

2. Photovoltaic module according to claim 1, wherein each electronic circuit (10) includes a resistor (R, m) in series with the light-emitting diode (LED).

3. Photovoltaic module according to claim 2, wherein, for each electronic circuit (10), the assembly comprising the resistor (R, pn) in series with the light-emitting diode (LED) is connected in parallel with the photovoltaic (PV) cell to which the electronic circuit (10) is connected.

4. Photovoltaic module according to any one of claims 1 to 3, wherein each photovoltaic (PV) cell comprises a first cell terminal (C+) and a second cell terminal (C-), the photovoltaic (PV) cell being configured to supply an electric current flowing from the second cell terminal (C-) to the first cell terminal (C+) when it receives light, and wherein, for each electronic circuit (10), the anode of the light-emitting diode (LED) of the electronic circuit (10) is coupled to the second cell terminal (C-) of the photovoltaic (PV) cell to which the electronic circuit (10) is connected and the cathode of the light-emitting diode (LED) of the electronic circuit (10) is coupled to the first cell terminal (C+) of the photovoltaic (PV) cell to which the electronic circuit (10) is connected.

5. Photovoltaic module according to any one of claims 1 to 4, wherein each photovoltaic (PV) cell comprises a silicon plate (60) having first and second opposite faces, and wherein at least a portion of the electronic circuits (10) are located along the photovoltaic (PV) cells, or between the photovoltaic (PV) cells, or on the first faces of the silicon plates (60) or on the second faces of the silicon plates (60).

6. Photovoltaic module any one of claims 1 to 5, wherein each electronic circuit (10) comprises at least two light-emitting diodes (LED, LED').

7. A system comprising a photovoltaic module according to any one of claims 1 to 6, wherein the photovoltaic module (Mod) comprises a first module terminal (M+) and a second module terminal (M-), the photovoltaic module (Mod) being configured to provide an electric current flowing from the second module terminal (M-) to the first module terminal (M+) when the photovoltaic (PV) cells receive light, the system further comprising a voltage generator (20) configured to apply a negative voltage (UM) between the first module terminal (M+) and the second module terminal (M-).

8. System according to claim 7, wherein the voltage generator (20) is a device separate from the photovoltaic module (Mod) configured to be manually connected to the photovoltaic module (Mod).

9. A method for detecting photovoltaic (PV) cell failures in a photovoltaic module (Mod) according to any one of claims 1 to 6, the photovoltaic module (Mod) comprising a first module terminal (M+) and a second module terminal (M-), the method comprising the following steps: - applying a negative voltage (UM) between the first module terminal (M+) and the second module terminal (M-); and - determining whether the amount of light emitted by at least one of the light-emitting diodes (LEDs) is less than the amount of light emitted by other LEDs among the LEDs.

10. A fault detection method according to claim 9, wherein the negative voltage (UM) applied between the first module terminal (M+) and the second module terminal (M-) is variable.

11. A method for detecting faults according to claim 9 or 10, further comprising the following steps, in order: a) measuring a first leakage current of a fault-free photovoltaic (PV) cell identical to the photovoltaic (PV) cells of the photovoltaic module (Mod); b) measure the electrical power supplied by the photovoltaic (PV) cell under illumination; c) create a defect in the photovoltaic (PV) cell and measure the electrical power supplied by the photovoltaic (PV) cell with the defect under said illumination; d) repeat step c) until the measured electrical power falls below a threshold; e) measure a second leakage current from the defective photovoltaic (PV) cell; and f) determine the characteristics of the light-emitting diode (LED) of each electronic circuit (10) from the first leakage current and the second leakage current.

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