Automated method and system for solar panel repair

Abstract

The invention relates to an automated method and system for solar panel repair, wherein the method comprises: a) detecting, using at least one detection means, at least one defective cell in at least one solar panel; b) making at least one incision, using at least one cutting means, in the rear face of at the least one solar panel to expose the contacts of the at least one defective cell; c) printing on the rear face of the at least one solar panel, using at least one direct writing means with ink, at least one marking comprising at least one compound containing at least one metallic element with a load of at least 80%, following a random pattern to short-circuit the at least one defective cell; d) sintering the at least one marking, using at least one energy application means, thereby transforming the marking into at least one metallic circuit; and e) encapsulating the at least one printed circuit, using at least one encapsulating means, which applies at least one insulating element.

Description

An automated method and system for solar panel recovery DESCRIPTIVE MEMORANDUM

[0001] The present invention relates to an automated method and system for recovering solar panels, intended for industries or applications where solar panels are used extensively, such as the power generation sector, or any sector or industry that bases part or all of its energy consumption on photovoltaic generation. The method and system of the invention prevents defective solar panels, whose generation capacity has been reduced by the failure of one or more cells, from being removed or discarded, allowing them to be reintegrated into the generation process or used in less critical generation processes.

[0002] In this sense, the method and system of the invention proposes to introduce a permanent bypass in the internal circuit of defective solar panels using additive manufacturing techniques to recover most of their energy generation capabilities.

[0003] Specifically, the method of the invention essentially comprises the steps of: detecting, by means of at least one detecting means, at least one defective cell in at least one solar panel; making at least one incision, by means of at least one cutting means, on the back face of at least one solar panel to expose the contacts of the at least one defective cell; printing on the back face of the at least one solar panel, by means of at least one direct ink writing means, at least one trace comprising at least one compound with at least one metallized element with a charge of at least 80% metallic particles, following an arbitrary pattern to short-circuit the at least one defective cell; sintering the at least one trace, by means of at least one energy application means, transforming it into at least one metallic circuit; and encapsulating the at least one printed circuit, by means of at least one encapsulating means, which applies at least one insulating element.

[0004] Furthermore, the system of the invention essentially comprises at least one detection means for detecting at least one defective cell in at least one solar panel; at least one cutting means for making at least one incision on the back face of at least one solar panel to expose the contacts of the at least one defective cell; at least one direct ink writing means for printing on the back face of the at least one solar panel at least one trace comprising at least one compound with at least one metallized element with a charge of at least 80%, following an arbitrary pattern to short-circuit the at least one defective cell; at least one energy application means for sintering the at least one trace, transforming it into at least one metallic circuit; and at least one encapsulating means for encapsulating the at least one printed circuit by applying at least one insulating element.

[0005] Based on the method and system of the invention, it is possible to reincorporate into the electricity generation chain photovoltaic modules that, under current conditions, would be discarded, thus contributing to technological reuse without significantly affecting the operating and generation conditions, and with the consequent contribution to the environment. BACKGROUND

[0006] In the electricity generation industry, the installed capacity of solar power plants, which operate with photovoltaic modules, has increased exponentially in recent years. This has led to the management of waste generated from defective photovoltaic modules becoming a significant challenge that the renewable energy sector needs to address if it aspires to be sustainable.

[0007] Photovoltaic modules can be removed from power plants. On the one hand, some modules will obviously be removed because they are defective. On the other hand, however, modules may be disconnected and replaced to maximize the plant's yield ratio, or because the plant is undergoing a major renovation to better utilize the available solar irradiance at the site. In that case, many of the modules to be disconnected, although degraded, may still be operational. Therefore, modules removed from power plants can be classified into one of the following two groups: 1) The module is partially degraded, but still within the limits of the linear performance guarantee; or 2) The module is defective and does not meet its linear performance guarantee.

[0008] The modules in group 2) can be further subdivided into those that can be repaired based on information gathered by the scientific community, and those that cannot be repaired for technical or economic reasons. Of course, all photovoltaic modules will eventually fail to a degree where repair is not technically or economically viable. They will then have to be transported to recycling facilities or landfills. However, some of them can be repaired. In this respect, the scientific community agrees that module reuse generates the highest revenue with the fewest processing steps (including energy and materials), while material extraction leads to the lowest revenue with the most processing steps. Therefore, reusing photovoltaic modules represents an opportunity, given that it allows: 1) Alleviate the growing demands for landfill space; 2) To recover part of the economic value of defective photovoltaic modules, contributing to the emergence of a second-life module market; and 3) Promote the development of value-added services for the photovoltaic industry.

[0009] Not all failures can be repaired using a single method. In other words, the repair method for a module depends on the type of failure it experiences, and the occurrence of any failure subsequently depends on a long list of factors: solar irradiance and local climate, module connection within the plant, operation and maintenance history, module and cell architecture, etc.

[0010] The present invention teaches a method that allows the recovery of most of the generating capacity of the module if it experiences one or more failures in its cells, produced, for example, by discoloration of the internal circuit, increase in series resistance, solder failure, hot spots or fractured cells, among other failures that could occur in the module, in order to change the state of the module from "defective" to "operational".

[0011] At this point, it is crucial to distinguish between repair and recovery or reconditioning. In a repair, a device is returned to its original state, as if it came from the assembly line. However, in the photovoltaic industry, performing such a procedure on a defective module is economically unfeasible. Thus, the opportunity arises only if the methodology recovers some of the module's energy generation capabilities with minimal processing. This is why the present invention proposes reconditioning or recovery instead of repairing modules.

[0012] In the state of the art, there are solutions that aim at the repair or reconditioning of photovoltaic modules.

[0013] For example, US patent 10763383B2 relates to a method of electrically connecting first and second conductive elements, comprising inserting a nanometallic material between the first and second conductive elements; and heating the nanometallic material to a melting temperature to form the electrical connection between the first and second conductive elements. The nanometallic material may comprise a nanometallic paste or ink composed of one or more nanoparticles of gold (Au), copper (Cu), silver (Ag), and / or aluminum (Al) that melt or fuse into a solid to form the electrical connection, at a melting temperature of around 150–250°C, and more preferably around 175–225°C.The electrical connection can be formed between a solar cell and a substrate by creating a via in the solar cell between a front and rear side of the solar cell, wherein the via is connected to a contact on the front side of the solar cell and a trace in the substrate.

[0014] According to this document, it can be observed that it generically addresses some of the characteristics of the present invention, such as the connection of photovoltaic cells using traces incorporating metallic nanoparticles or the metallization of said traces through a heat treatment. However, this document does not achieve the technical effect of the present invention through the proposed reconditioning methodology, which aims to keep commercial panels with defective cells operational, with an encapsulation and hermeticity standard very close to that of the other, unmodified panels. Among the differences between patent US10763383B2 and the present invention are They may mention: the automation of the drilling process on the back of the photovoltaic module to access the internal circuit; the automated printing of the traces or circuits that allow a bypass between the cells in good condition; the synthesis of the traces, transforming them into a metallic circuit by applying thermal energy, acid vapors or others; and the encapsulation of the printed circuit by applying an insulating resin, minimizing any potential exposure of the cells to the environment.

[0015] Furthermore, US patent 10075128B2 describes a solar module and a method for manufacturing a solar module, wherein the solar module comprises at least one solar cell; at least two connection elements for establishing an electrical connection with the at least one solar cell; a shunt component connected to the connection elements; and a junction box in which the shunt component is provided, wherein the junction box comprises an encapsulation material that at least partially covers the shunt component. According to the invention, the junction box comprises at least one connection area that is free of encapsulation material, in which a shunt component and / or another electronic component can be connected to the connection elements, using the connection area. The invention also relates to a method for repairing and / or adapting a solar module.

[0016] Upon reviewing the description in US patent 10075128B2, it is observed that there are some elements that could be considered by an expert attempting to reproduce the present invention, such as the use of the clamp-type connection disclosed therein. However, that document neither describes nor suggests the specific steps for reconditioning a photovoltaic module, nor the automation of that methodology.

[0017] The significance of the present invention stems from the various positive externalities created and promoted by the proposed method and system. On the one hand, it provides an incentive to enhance current capabilities related to the maintenance of photovoltaic modules. Since the method is based on a combination of additive manufacturing techniques, its development creates an environment where new insulating resins, novel solutions of advanced or specially adapted metallic nanoparticles, and customized laser cutting and sintering techniques flourish, thus driving the development of applied science. Furthermore, the invention stimulates and encourages the development of applied research on the degradation of photovoltaic modules, identifying changes from their initial state, both on the surface and in the volume of the solar cells.

[0018] Therefore, it is necessary to have a method and system that is not only capable of reconditioning one or more modules in an automated way, with the consequent increase in productivity, but also requires a solution that uses reconditioning techniques that manage to provide a reconditioned module with high durability and operational capacity, compared to modules without defects.

[0019] This and other advantages associated with other aspects of the technology are described in more detail below. DESCRIPTION OF THE INVENTION

[0020] The invention relates to an automated method and system for recovering solar panels that prevents defective solar panels, in which their generation capacity has been reduced by the failure in one or more cells, from being discarded, allowing them to be reincorporated into the generation process in which they were found, or to be used in less critical generation processes.

[0021] According to a first preferred embodiment of the invention, the automated method for recovering solar panels comprises the steps of: a) detecting, by means of at least one detecting means, at least one defective cell in at least one solar panel; b) making at least one incision, by means of at least one cutting means, on the back face of at least one solar panel to expose the contacts of the at least one defective cell; c) printing on the back face of the at least one solar panel, by means of at least one direct writing means with ink, at least one trace comprising at least one compound with at least one metallized element with a charge of at least 80%, following an arbitrary pattern to short-circuit the at least one defective cell; d) sintering the at least one trace, by means of at least one energy application means, transforming it into at least one metallic circuit;(e) encapsulate at least one printed circuit board, by means of at least one encapsulating medium, which applies at least one electrical insulating element that also constitutes a mechanical barrier to prevent the exposure of the internal circuitry to external agents of degradation, such as humidity, dust, etc.;

[0022] According to another embodiment of the invention, the method further comprises, prior to step a), positioning the at least one detector medium on the at least one solar panel, by means of at least one unmanned aerial vehicle (UAV), or another method that gives controlled mobility to the at least one detector medium.

[0023] According to another embodiment of the invention, step a) further comprises performing electrical tests under standard conditions and / or optoelectronic tests on at least one solar panel to determine the location of defects and the magnitude of power loss. Preferably, the electrical tests correspond to the current-voltage characteristic curve or similar tests, and the optoelectronic tests correspond to the measurement of luminescence or thermography.

[0024] According to another embodiment of the invention, the method further comprises, prior to step b), positioning the at least one panel with its back face upwards within the at least one cutting means.

[0025] According to another embodiment of the invention, in step b) at least one incision has a circular or polygonal shape.

[0026] According to another embodiment of the invention, step b) further comprises adjusting the power of the at least one cutter means in a range between 20 W and 40 W, which is distributed homogeneously in a circle of radius between 0.05 mm and 0.15 mm if the at least one cutter means corresponds to a laser cutting equipment.

[0027] According to another embodiment of the invention, step b) further comprises adjusting the cutting time of the at least one cutter half in a range between 30 s and 120 s, when the at least one cutter half makes incisions at a speed in a range between 120 mm / s and 180 mm / s.

[0028] According to another embodiment of the invention, in step d) the applied energy is thermal energy, where the trace temperature is adjusted to a value between 120 °C and 200 °C, for a time in the range between 10 minutes and 60 minutes.

[0029] According to another embodiment of the invention, step d) further comprises applying at least one type of acid vapor, such as hydrochloric acid vapor.

[0030] Furthermore, according to a second preferred embodiment of the invention, an automated solar panel recovery system is also described, comprising: at least one detector means for detecting at least one defective cell in at least one solar panel; at least one cutting means for making at least one incision on the back face of at least one solar panel to expose the contacts of the at least one defective cell; at least one direct ink writing means for printing on the back face of the at least one solar panel at least one trace comprising at least one compound with at least one metallized element with a charge of at least 80%, following an arbitrary pattern to short-circuit the at least one defective cell; at least one energy application means for sintering the at least one trace, transforming it into at least one metallic circuit;and at least one encapsulating means, to encapsulate at least one printed circuit board by applying at least one insulating element.;

[0031] According to another embodiment of the invention, the system further comprises at least one unmanned aerial vehicle or other equipment that provides controlled mobility to the at least one detector medium, which allows positioning the at least one detector medium on the at least one solar panel.

[0032] According to another embodiment of the invention, the at least one detector means is at least one infrared camera.

[0033] According to another embodiment of the invention, the at least one cutting means is at least one laser cutting equipment.

[0034] According to another embodiment of the invention, the at least one means of direct ink writing is a printed circuit board (PCB) printer.

[0035] According to another embodiment of the invention, the shape of at least one metallized element corresponds to at least one of the metallized nanoparticles, sequins and / or flakes.

[0036] According to another embodiment of the invention, the at least one metallized element corresponds to at least one of silver, copper, or a combination of these.

[0037] According to another embodiment of the invention, the at least one means of applying energy corresponds to at least one of a heat gun, a heating plate, and a laser.

[0038] According to another embodiment of the invention, the at least one encapsulating means corresponds to at least one sprayer.

[0039] According to another embodiment of the invention, the at least one insulating element corresponds to at least one resin. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

[0040] The following section describes a preferred embodiment of the invention, in accordance with the characteristics set forth for the method and the automated system

[0041] The described method and system can address many of the photovoltaic module failures reported in the literature. To achieve this, the invention describes creating a short circuit in the defective cells of a monofacial photovoltaic module, effectively bypassing them within the module's electrical circuit. To understand what this means, a brief description of the main components of a photovoltaic module and their arrangement is necessary.

[0042] A photovoltaic module is a power generation device composed of several subunits called cells. These cells can be connected in series or in parallel, such that the module's main electrical parameters—VOC, ISC, FF, and PMax—are, except for connection losses, a direct combination of each cell's capacitance. Typical arrangements involve 60 or 72 full cells, or 120 or 144 half cells. In the first case, the full cells are connected in series, while in the second, 60 or 72 half cells are connected in series, forming two groups, which are then connected in parallel.

[0043] A photovoltaic module that exposes only one side to sunlight is called "monofacial," while one that exposes both sides is called "bifacial." Monofacial photovoltaic modules encapsulate their cells with a semi-transparent thermoplastic layer, often made of materials such as ethylene vinyl acetate (or 'EVA'), polyolefins (POE), or another combination of organic materials. On the side exposed to sunlight, these modules typically incorporate tempered glass approximately 3 mm thick coated with an anti-reflective coating, while on the opaque side, the encapsulant is covered with a film made from a combination of thermoplastics such as polyethylene terephthalate, polyvinylidene fluoride, and others. This is known as the "backsheet."

[0044] Bifacial modules, on the other hand, expose both sides to light, and therefore their manufacture requires combining a semi-transparent encapsulant with glass on both sides, or a semi-transparent plastic backsheet on the back face.

[0045] In this sense, most of the modules installed and operating in solar plants are surrounded by a metallic structure, typically made of aluminum, which provides support to the device.

[0046] Finally, commercial photovoltaic modules, whether monofacial or bifacial, typically incorporate a junction box, which allows the positive and negative terminals of the cells to be connected to the copper wire, enabling energy extraction from the device. This box incorporates three bypass diodes connected in parallel with three cell regions within the entire cell array. In this way, if a fault creates an open circuit in any of the cells, instead of disabling the energy generation capacity of the entire module, only one region will be short-circuited: the region associated with the bypass diode connected in parallel.

[0047] The present invention attempts to address this problem. Faults, such as discoloration of the internal circuitry and increased series resistance, internal circuit failure, solder failure, hot spots, and fractured cells, can be traced to one or more cells. If these cells fail, they can limit the current generated by the device under sunlight, or, if they completely interrupt the circuit, activate the corresponding bypass diode. Thus, the method and system of the invention addresses this problem by adding an electrical circuit that bypasses each faulty cell. This is accomplished by creating a short circuit between the cells adjacent to the faulty cell, thereby restoring the flow of direct current in the module, deactivating the bypass diode, and allowing the power generation capacity of the cells that were originally operational but bypassed by the bypass diode to be restored.This explains why the invention is able to address various types of cell failures.

[0048] As stated and discussed above, the method and system involves combining several additive manufacturing techniques to maximize reproducibility and maintain compatibility between individual prototypes and industrial-scale manufacturing.

[0049] Specifically, the method involves five steps. The first stage can be carried out using an infrared camera that detects the electroluminescence of the module, thus allowing the identification of the defective cell or cells.

[0050] The second stage involves making automated incisions in the backsheet of the monofacial photovoltaic module to be repaired. These incisions can be made using a laser cutter and are part of the process to expose the busbars that electrically connect the cells. Exposing the busbars is key to accessing the internal circuitry and bypassing the faulty cell. The number of incisions will vary depending on the number of busbars in the cell, with four incisions being the preferred number. The number of incisions will change depending on whether the module has fewer or more busbars.

[0051] The third stage involves printing a paste containing metallic nanoparticles, flakes, or other forms, so that the printed trace can later become electrically conductive. This can be done using commercial pastes containing silver nanoparticles with a charge of 80% or higher. However, whatever material is used, the key is being able to print it using direct ink writing techniques or similar methods, as these are compatible with both prototyping and industrial manufacturing.

[0052] The fourth stage involves sintering the trace, that is, transforming it into a metallic circuit by applying thermal energy, acid vapors, or another form of energy or mass. In this regard, silver nanoparticles can be manufactured for sintering at temperatures below 200 °C.

[0053] Finally, the fourth step involves encapsulating the printed circuit board and any exposed incisions by applying an insulating and protective resin. The purpose of this step is to reduce the exposure of the cells within the module, as well as the newly fabricated electrical circuit, to environmental degradation agents. In addition to various resins and solvents, several coating techniques can be used. These include direct ink application, as well as knife coating and spray coating—all compatible with industrial-scale manufacturing.

Claims

CLAIMS 1. An automated method for recovering solar panels, CHARACTERIZED in that it comprises: a) detecting, by means of at least one detection means, at least one defective cell in at least one solar panel; b) making at least one incision, by means of at least one cutting means, in the back face of at least one solar panel to expose the contacts of the at least one defective cell; c) printing on the back face of the at least one solar panel, by means of at least one direct ink writing means, at least one trace comprising at least one compound with at least one metallized element with a charge of at least 80%, following an arbitrary pattern to short-circuit the at least one defective cell; d) sintering the at least one trace, by means of at least one energy application means, transforming it into at least one metallic circuit; and e) encapsulating the at least one printed circuit, by means of at least one encapsulating means, which applies at least one insulating element.

2. The method according to claim 1, CHARACTERIZED in that it further comprises, prior to step a), positioning the at least one detector means on the at least one solar panel, by means of at least one unmanned aerial vehicle (UAV), or another method that gives controlled mobility to the at least one detector means.

3. The method according to claim 1, CHARACTERIZED in that step a) further comprises performing, on at least one solar panel, electrical tests under standard conditions and / or optoelectronic tests, to determine the location of the defects and the magnitude of the lost power.

4. The method according to claim 3, CHARACTERIZED in that the electrical tests correspond to the current-voltage characteristic curve or similar ones, and the optoelectronic tests correspond to the measurement of luminescence or thermography.

5. The method according to any of claims 1-4, CHARACTERIZED in that it further comprises, prior to step b), positioning the at least one panel with its rear face upwards within the at least one cutting means.

6. The method according to any of claims 1-5, CHARACTERIZED in that in step b) the at least one incision is circular in shape.

7. The method according to any of claims 1-5, CHARACTERIZED in that in step b) the at least one incision has a polygonal shape.

8. The method according to any of claims 1-7, CHARACTERIZED in that step b) further comprises adjusting the power of the at least one cutter means in a range between 20 W and 40 W, which is distributed homogeneously in a circle of radius between 0.05 mm and 0.15 mm if the at least one cutter means corresponds to a laser cutting equipment.

9. The method according to any of claims 1-8, CHARACTERIZED in that step b) further comprises adjusting the cutting time of the at least one cutter half in a range between 30 s and 120 s, when the at least one cutter half makes incisions at a speed in a range between 120 mm / s and 180 mm / s.

10. The method according to any of claims 1-9, CHARACTERIZED in that in step d) the applied energy is thermal energy, wherein the trace temperature is adjusted to a value between 120 °C and 200 °C, for a time in the range of 10 minutes to 60 minutes.

11. The method according to any of claims 1-10, CHARACTERIZED in that step d) further comprises applying at least one type of acid vapor, such as hydrochloric acid vapor.

12. An automated solar panel recovery system according to the method of claims 1-11, CHARACTERIZED in that it comprises: - at least one detection means, for detecting at least one defective cell in at least one solar panel; at least one cutting means, for making at least one incision on the back face of at least one solar panel, to expose the contacts of the at least one defective cell; at least one direct ink writing means, for printing on the back face of the at least one solar panel at least one trace comprising at least one compound with at least one metallized element with a charge of at least 80%, following an arbitrary pattern to short-circuit the at least one defective cell; at least one means of applying energy, to sinter the at least one trace, transforming it into at least one metallic circuit; and at least one encapsulating means, to encapsulate the at least one printed circuit by applying at least one insulating element.

13. The system according to claim 12, CHARACTERIZED in that it further comprises at least one unmanned aerial vehicle or other equipment that gives controlled mobility to the at least one detector means, which allows the at least one detector means to be positioned on the at least one solar panel.

14. The system according to any of claims 12-13, CHARACTERIZED in that the at least one detector means is at least one infrared camera.

15. The system according to any of claims 12-14, CHARACTERIZED in that the at least one cutting means is at least one laser cutting equipment.

16. The system according to any of claims 12-15, CHARACTERIZED in that the at least one direct ink writing means is a printed circuit board (PCB) printer.

17. The system according to any of claims 12-16, CHARACTERIZED in that the shape of at least one metallized element corresponds to at least one of metallized nanoparticles, sequins and / or flakes.

18. The system according to any of claims 12-17, CHARACTERIZED in that the at least one metallized element corresponds to at least one of silver, copper, or a combination of these.

19. The system according to any of claims 12-18, CHARACTERIZED in that the at least one energy application means corresponds to at least one of a heat gun, a heating plate, and a laser.

20. The system according to any of claims 12-19, CHARACTERIZED in that the at least one encapsulating means corresponds to at least one sprayer.

21. The system according to any of claims 12-20, CHARACTERIZED in that the at least one insulating element corresponds to at least one resin.