AUTOMATED ASSEMBLY AND MOUNTING OF SOLAR CELLS ON SPACE PANELS

Description

BACKGROUND OF THE INVENTION

[01] 1. Scope of the invention

[02] The present invention relates to the field of photovoltaic solar networks, and more specifically manufacturing processes using, for example, multi-junction solar cells based on type III-V semiconductor compounds prepared as interconnected assemblies of the cell-interconnect-cover glass (CIC) type and mounted on a support or substrate by automated processes.

[03] 2. Description of the related technique

[04] Solar energy derived from photovoltaic cells, also known as cells Solar power has been supplied primarily by silicon-based semiconductor technology. In recent years, however, the large-scale manufacturing of III-V compound semiconductor multijunction solar cells for space applications has accelerated the development of this technology, not only for use in space but also for terrestrial solar power applications. Compared to silicon, III-V compound semiconductor multijunction devices exhibit higher energy conversion efficiencies and, generally, greater resistance to radiation, although they tend to be more complex to manufacture.Typical commercial III-V compound semiconductor multijunction solar cells have energy efficiencies exceeding 27% under atmospheric mass 0 (AMO) solar illumination, whereas the most efficient silicon technologies typically achieve only about 18% efficiency under comparable conditions. Under high solar concentration (e.g., 500X), commercially available III-V compound semiconductor multijunction solar cells in terrestrial applications (at AM1.5D) have energy efficiencies exceeding 37%. The highest conversion efficiency of semiconductor solar cells... III-V compound by comparison to silicon solar cells is based in part on the ability to achieve spectral cleavage of incident radiation by using a series of photovoltaic regions with different band gap energies, and the accumulation of current from each of the regions.

[05] In satellites and other space applications, the size, mass and costs of a A satellite's power system depends on the power and energy conversion efficiency of the solar cells used. In other words, the size of the payload and the availability of onboard services are proportional to the amount of energy supplied. Thus, as the payload becomes more sophisticated, the power-to-weight ratio of a solar cell becomes increasingly important, and there is a growing interest in lower weight, with thin-film solar cells offering both high efficiency and low mass.

[06] Space applications frequently use highly efficient solar cells, Specifically, multijunction solar cells based on III-V compound semiconductors. Typical III-V compound semiconductor solar cells are manufactured on a semiconductor wafer in vertical multijunction structures. Individual solar cells or wafers are then arranged in horizontal arrays, with individual solar cells connected to each other in a series and / or parallel electrical circuit. The shape and structure of an array, as well as the number of cells it contains, are determined in part by the desired output voltage and current.

[07] Conventional space-based solar panels are currently composed of the most These solar arrays often consist of a relatively dense arrangement of large solar cells made of III-V compound semiconductor devices, mounted on a rigid support panel and operating without lenses for optically concentrating sunlight. A typical space-based solar array panel might include a support, space-based solar cells arranged on the support, interconnecting components to link the solar cells, and bypass diodes also connected to the solar cells.

[08] Solar panels are generally formed by combining a large number of solar cells on a grid. Individual solar cells, frequently rectangular or square in shape and sometimes with cut corners, are Three solar cells are connected in series to form a strip of solar cells, where the number of solar cells used in the strip determines the output voltage. Solar cells or strips of solar cells can also be interconnected in parallel to increase the output current. In space applications, individual solar cells are fitted with interconnects and a cover glass to form so-called CIC (cell-interconnect-cover glass) assemblies, which are then combined to form an array. Traditionally, these large solar cells were mounted on a support and interconnected using a significant amount of manual labor. For example, early individual CICs were produced with each interconnect individually soldered to each cell and each cover glass mounted individually.Next, these ICs are connected in series to form strips, usually in a substantially manual manner, including welding or brazing steps. Then, these strips are applied to a panel or substrate and interconnected, in a process that includes the application of an adhesive, the laying of wires, and other assembly steps.

[09] A compact arrangement of large solar cells on the grid panel Space solar power is challenging due to the requirement to interconnect solar cells to form a series circuit and to implement and interconnect bypass diodes. An additional challenge can sometimes arise from the need to interconnect a series of series-connected solar cell strips in parallel. All of this has usually been done manually, which is very time-consuming.

[10] There is a continuing need for improved manufacturing and assembly processes of photovoltaic solar networks, which can result in cost reductions and / or performance increases. SUMMARY OF THE INVENTION

[11] 1. Objects of the invention

[12] An object of the present invention consists of an automated method for the production of solar cell panels for space applications.

[13] Another object of the present invention is an automated assembly tool for the production of solar cell panels for space applications.

[14] An object of the invention consists of a power supply cassette comprising a series of series-connected solar cell assemblies, which can be used in an automated process of forming a solar array by automatic placement and adhesion of said solar cell assemblies onto the support.

[15] Another object of the invention is a method for manufacturing a panel solar cells.

[16] Another object of the invention consists of a structure and a method of assembly, which facilitates the automation of at least some steps in the manufacturing process of solar cell assemblies or CICs and interconnected CIC panels.

[17] Certain implementations of the present invention may include or use some of the aspects and characteristics mentioned in the previous items.

[18] 2. Characteristics of the invention

[19] Briefly and in general terms, the present invention relates to a method of manufacturing a solar cell panel using an automated process. For example, a manufacturing process for a multijunction solar cell array is hereby described, comprising one or more of the following steps: manufacturing a wafer using a metal-organic precursor chemical vapor deposition (MOCVD) reactor; metallizing the back side of the wafer, creating a pattern by lithography and deposition of metal on the front side of the wafer; forming a mesa on the front side of the wafer by lithography and etching; deposition of an antireflective coating (RAR) on the wafer; cutting one or more solar cells from the wafer; testing the functionality of the solar cell(s); attaching the interconnects to the solar cell(s); attaching a cover glass to each solar cell to form a cell-interconnect-cover glass (CIC);formation of a CIC strip configuration; interconnection of CIC strip configurations; linking of strip configurations or interconnected strip configurations on a substrate; panel circuit configuration and wiring; configuration of a blocking diode; wiring of a first and second terminal; first and second polarity terminals, respectively, for the solar cell panel; and testing the functionality of the solar cell panel; where at least one of the steps of the process is carried out by an automated process.

[20] In some embodiments, solar cells are solar cells III-V compound semiconductor-based multijunctions and wafer fabrication includes: the provision of a metal-organic precursor chemical vapor deposition (MOCVD) system, configured to independently control the flow rate of source gases for gallium, indium-aluminum and arsenic; the selection of a reaction time and temperature as well as a flow rate for each source gas to form the continuously graded interlayer disposed on the bottom subcell, where the source gas for indium is trimethyl-indium (InMej), the source gas for gallium is trimethyl-gallium (GaMes), the source gas for arsenic is arsine (AsHa), and the source gas for aluminum is trimethyl-aluminum (Al2Me6).

[21] In other embodiments, the making of a galette includes: the preparation of disposition of a first substrate; deposition on the first substrate of a series of layers of semiconductor material to form at least a first, a second and a third solar cell; formation of a dimming interlayer on said first, second and / or third solar cells; deposition on said dimming interlayer of a second series of layers of semiconductor material to form a fourth solar cell, the array of the fourth solar cell being offset with respect to the third solar cell; mounting and application of a substrate substitute on top of the series of layers, and removal of the first substrate, wherein the formation of the dimming interlayer comprises: sampling of an interlayer composed of InGaAlAs using a computer program to identify a series of compositions of the formula (InxGai.x)yAli.yAs defined by specific values ​​of x and y, where 0 < x < 1 and 0 < y < 1, each composition having a constant band gap; identify a lattice constant for one face of the gradation interlayer, which corresponds to the middle subcell and a lattice constant for an opposite face of the gradation interlayer, which corresponds to the bottom subcell, and identify a subset of compositions of the formula (InxGai.x)yAli.yAs having the constant band gap, which are defined by specific values ​​of x and y, where 0 < x < 1 and 0 < y < 1, and where the subset of compositions has constants of . 6 network going from the identified network constant, which corresponds to the adjacent sub-cell, to the identified network constant, which corresponds to the bottom sub-cell.

[22] In another embodiment, the present invention relates to a method of manufacturing a multijunction solar cell array on a substrate using one or more automated processes, the process comprising: providing a first multijunction solar cell comprising a first contact pad and a second contact pad, arranged adjacently on the upper surface of the multijunction solar cell along a first peripheral edge thereof; attaching a first electrical interconnection to the first contact pad of said first multijunction solar cell; attaching a second electrical interconnection to the second contact pad of the first multijunction solar cell; positioning said first multijunction solar cell on an adhesive region of a permanent substrate using an automated machine / vision device;the mounting of a cover glass on said first multijunction solar cell, and the bonding of said first multijunction solar cell to said adhesive region using pressure and / or heat.

[23] In certain embodiments of the invention, the support is a layer KAPTON® is a polyimide film coating. KAPTON® is a trademark of E.I. du Pont de Nemours and Company. The chemical name of KAPTON® is poly(4,4'-oxydiphenylene-pyromellitimide). Other polyimide film sheets or coatings may also be used.

[24] In some embodiments, the support has a thickness ranging from 25 to 100 microns, or from 1 mil (25.4 pm) to 4 mil (101.6 pm).

[25] In some embodiments, the support has a thickness ranging from 10 to 25 microns.

[26] In some embodiments, a metallic layer is attached to the layer of adhesive-free support, to limit outgassing during use in space.

[27] In some embodiments, the support is mounted on a honeycomb structure metallic.

[28] The substrate can be a rigid substrate, such as an aluminum honeycomb substrate with a carbon composite face sheet, or it can be a flexible substrate, such as a polyimide film.

[29] In some embodiments, after preparing the linking connection, at at least two solar cell devices are automatically interconnected using a "pick and place" process to position the interconnectors, followed by automatic parallel capillary welding.

[30] In some embodiments, the contact pads are established by a automated metal plating process.

[31] In some embodiments, the at least two solar cell devices are electrically connected, automatically, for example by wiring, the at least two solar cell devices having coplanar electrical contacts facing each other.

[32] In another aspect, the present invention relates to a space vehicle and its manufacturing process, comprising: a payload disposed on or in the space vehicle and a power source for the payload, comprising an array of solar cell assemblies mounted on a panel, at least one solar cell panel or solar cell assembly being of the type described herein.

[33] Certain implementations of the present invention may include or use some of the aspects and characteristics noted in the previous summaries.

[34] Aspects, additional advantages and new features of the The present invention will be obvious to a person skilled in the art upon reading this description, including the following detailed description, and by carrying out the invention. Although the invention is described below with reference to preferred embodiments, it should be understood that the invention is not limited to them. A person skilled in the art, having access to these descriptions, will discover additional applications, modifications, and embodiments in other fields that fall within the scope of the invention as described and claimed herein and in relation to which the invention may be useful. BRIEF DESCRIPTION OF THE DRAWINGS

[35] To complete the invention and to provide a better understanding thereof Herein, a series of drawings is provided. These drawings form an integral part of the description and illustrate embodiments of the invention, which should not be interpreted as limiting the scope of the invention, but only as examples of how the invention can be implemented. The drawings include the following figures:

[36] Figure IA is a top view of a disc with two solar cells placed in artwork ;

[37] Figure IB is a top view of a disc with a solar cell placed in artwork ;

[38] Figure 2A is a top view of part of a solar cell according to the present invention;

[39] Figure 2B is a cross-sectional view of a multijunction solar cell, along the plane 2B-2B of the solar cell in Figure 2A;

[40] Figure 2C is a cross-sectional view of a solar cell of Figure 2A along the plane 2C-2C of figure 2A;

[41] Figure 2D is a plan view of part of a solar cell with cut corners and interconnection elements;

[42] Figure 2E is a perspective view of part of a solar cell with corners cut from figure 2A, representing more specifically the interconnection elements;

[43] Figure 2F is a cross-sectional view of the solar cell of Figure 2A along the plane 2C-2C shown in Figure 2A after connection of an interconnecting element;

[44] Figure 2G is a top view of the solar cell of Figure 2A after fixation of a cover glass to thus form a cell-interconnection-cover glass (CIC);

[45] Figure 2H is a cross-sectional view of the cell-interconnect-cover glass (CIC) of figure 2G according to the 2H-2H plane shown in figure 2A;

[46] Figure 21 is a cross-sectional view of part of the solar cell of Figure 2A, which was interconnected to an adjacent solar cell using the interconnecting element shown in Figure 2F;

[47] Figure 3 is a flowchart representing a process according to a form of realization of the present invention;

[48] ​​Figure 4 is a perspective view of a metallic honeycomb structure, which may to be used to mount a bracket;

[49] Figure 5 is a cross-sectional view of an aluminium honeycomb structure with foil front made of carbon composite, and

[50] Figure 6 is a cross-sectional view of an aluminium honeycomb structure with foil front made of carbon composite and co-crosslinked polyimide substrate. DESCRIPTION OF ILLUSTRATIVE FORMS OF REALIZATION

[51] Details of the present invention will now be described, including aspects Examples and embodiments thereof. With reference to the drawings and the following description, identical reference numbers are used to identify identical elements or elements of similar functionality and are intended to illustrate major features of exemplary embodiments in highly simplified diagrams. Furthermore, the drawings are not intended to represent every feature of the embodiment in question, nor the relative dimensions of the elements shown; they are not drawn to scale.

[52] The present invention can be adapted to multijunction solar cells such as described in the related applications, which may include three, four, five or six subcells, with forbidden bands in the range of 1.8 to 2.2 eV (or more) for the top subcell; 1.3 to 1.8 eV and 0.9 to 1.2 eV for the middle subcells, and 0.6 to 0.8 eV for the bottom subcell.

[53] The present invention relates to an apparatus and methods for automating several of the processes and handling steps associated with the manufacturing and assembly of a covered interconnected cell or "CIC" using cells multijunction solar cells, and the mounting of such CICs on a solar panel or support. More specifically, the present invention relates to a relatively simple and reproducible technique, suitable for use in high-volume production, where different semiconductor layers are deposited in a MOCVD reactor, and subsequent processing steps are defined and selected to minimize any physical damage to the solar cell and the quality of the semiconductor devices, thus ensuring a relatively high yield of functional solar cells meeting specifications at the end of the manufacturing processes.

[54] Figure 1A is a top view of a disc with two solar cells (cell 1 and cell 2) implementations.

[55] Figure IB is a top view of a disc with a single solar cell (cell 3).

[56] Figure 2A is a top view of part of a 900 solar cell according to the present invention, representing the metallic grid layers 940 and the metallic contact pad 952 adjacent to the peripheral edge regions 950 and 951 of the solar cell 900.

[57] Figure 2B is a cross-sectional view of a multijunction solar cell along the plane 2B-2B of the solar cell in Figure 2A, which can be used as an example in which the processes presented by the present invention can be implemented. In Figure 2B, each dashed line indicates the active region junction between a base layer and the emitter layer of a subcell.

[58] As shown in the example illustrated in Figure 2B, the bottom subcell 901 includes a substrate 912 made of p-type germanium (“Ge”), which also serves as the base layer. A contact pad 911 can be formed on the bottom of the base layer 912 to produce electrical contact with the multijunction solar cell 303. The bottom subcell 901 further includes, for example, a heavily doped n-type Ge emitter-forming layer 914, and an n-type indium gallium arseide (“InGaAS”) nucleation layer 916. The nucleation layer is deposited on the base layer 912, and the emitter-forming layer is formed in the substrate by diffusion of Ge deposits into the substrate, thus forming the n-type Ge layer 914. The tunneling junction layers 918, 917 are made of heavily doped p-type indium gallium arseide. 11 doped (“AlGaAs”) and heavily doped n-type gallium arseide (“GaAs”) can be deposited on the nucleation layer 916 to give a low-resistance path between the bottom and central subcells.

[59] In the example illustrated in Figure 2B, the central subcell 902 comprises a The back surface field (BSF) layer 920 consists of heavily doped p-type gallium aluminum arseide (“AlGaAs”), a p-type InGaAs base layer 922, a heavily doped n-type gallium indium phosphide (“InGaP2”) emitter-forming layer 924, and a heavily doped n-type aluminum indium phosphide (“AlInP2”) window layer 926. The InGaAs base layer 922 of the central subcell 902 may contain, for example, about 1.5% In. Other compositions may also be used. The base layer 922 is formed on the BSF layer 920 after the latter has been deposited on the tunneling junction layers 918 of the bottom subcell 901.

[60] The BSF 920 layer is applied to reduce recombination loss in the Central subcell 902. The BSF layer 920 carries minority charges from a heavily doped region near the back face to minimize recombination loss. Thus, the BSF layer 920 reduces recombination loss on the back face of the solar cell and thereby reduces recombination at the base layer / BSF layer interface. The window layer 926 is deposited on the emitter-forming layer 924 of the central subcell 902. The window layer 926 in the central subcell 902 also helps reduce recombination loss and improves the passivation of the cell surface at the underlying junctions. Before depositing the top cell layers 903, tunneling junction layers 927, 928 made of heavily doped n-type InGaP and p-type AlGaAs can be deposited on the central subcell 902.

[61] In the illustrated example, the top subcell 909 includes a BSF 930 layer in heavily doped p-type indium gallium aluminum phosphide (“InGaAlP”), a p-type InGaP2 base layer 932, a heavily doped n-type InGaP2 emitter-forming layer 934, and a heavily doped n-type InAlP2 window layer 936. The base layer 932 of the top cell 903 is deposited on the BSF layer 930 after having formed the latter on the tunneling junction layers 928 of the central subcell 902. The window layer 936 is deposited on the emitter-forming layer 934 of the The top subcell, after forming the emitter-forming layer 934 on the base layer 932, is then deposited. A cover or contact layer 938 can be deposited with patterns in separate contact regions on the window layer 936 of the top subcell 903. The cover or contact layer 938 serves as an electrical contact between the top subcell 903 and the metal grid layer 940. The doped cover or contact layer 938 can be a semiconductor layer, such as a GaAs or InGaAs layer.

[62] After depositing the cover or contact layer 938, the grid lines 940 are formed. The grid lines 940 are deposited by evaporation, then the pattern is created by lithography and deposited on a cover or contact layer 938. The mask is then moved to form the finished metallic grid lines 940 as shown in Figure 2B, and the part of the cover layer that has not been metallized is removed, to expose the surface of the window layer 936.

[63] In some embodiments, a trench or a canal 971 represented at the Figure 2C, or part of the semiconductor structure, is also etched around each of the solar cells. These 971 channels define a peripheral boundary between the solar cell (to be traced later from the wafer) and the rest of the wafer, and leave a mesa structure (or a series of mesas, in the case of more than one solar cell per wafer), which define and constitute the solar cells to be traced and cut from the wafer.

[64] As described in US Patent Application Publication No. 2010 / 0012175 Al (Varghese et al.), the 940 grid lines are preferably composed of Ti / Au / Ag / Au, although other suitable materials can also be used.

[65] During the formation of the metallic contact layer 940 deposited on the layer of semiconductor contact p+ 938, and during the subsequent stages of the process, the semiconductor body and its associated metallic layers and related structures will undergo various heating and cooling processes, which can subject the surface of the semiconductor body to stress. Thus, it is desirable to carefully match the coefficient of thermal expansion of the associated layers or structures to that of the semiconductor body, while maintaining appropriate electrical conductivity and structural properties of the layers or structures. Thus, in some embodiments, the metallic layer The 940 contact layer is chosen to have a coefficient of thermal expansion (CTE) substantially similar to that of the adjacent semiconductor material. In relative terms, the CTE can differ from that of the adjacent semiconductor material by 0 to 15 ppm per Kelvin. For the specific semiconductor materials described above, in absolute terms, a suitable coefficient of thermal expansion for the 940 layer will be in the range of 5 to 7 ppm per Kelvin. A variety of metallic compositions and multilayer structures containing molybdenum will meet these criteria.In certain embodiments, layer 940 will preferably comprise the sequence of metallic layers Ti / Au / Mo / Ag / Au, Ti / Au / Mo / Ag, or Ti / Mo / Ag, where the thickness ratios of each layer in the sequence are adjusted to minimize the shift of the CTEs to GaAs. Other suitable sequences and compositions may be used instead of those described above.

[66] In certain embodiments, the chosen metallic contact scheme is that which has a planar interface with the semiconductor, after heat treatment to activate ohmic contact. This is achieved so that (i) a dielectric layer separating the metal from the semiconductor does not need to be deposited and is selectively etched in the metal contact areas; and (ii) the contact layer exhibits specular reflection over the range of wavelengths of interest.

[67] The grid lines are used as a mask to etch the surface of the layer window 936 using a citric acid / peroxide etching mixture.

[68] A layer of anti-reflective dielectric coating (ARC) 942 is applied across the entire surface on the "top" side of the pancake with the 940 grid lines.

[69] Figure 2C is a highly simplified cross-sectional view of the solar cell of the Figure 2A is similar to that of Figure 2B, but shown in a longitudinal view along a grid line. The cross-sectional view of the solar cell in Figure 2A is taken along the 2C-2C plane. A contact pad 952 electrically connected to the grid line metal 940 is shown.

[70] Figure 2D is a top view of part of a 900 solar cell with corners cut out 991 and 992 near a peripheral edge 900 of the solar cell 900. The Figure 14 2D also represents interconnection elements 962 and 972, and metallic grid layers 940.

[71] Figure 2E is a perspective view of part of a 900 solar cell with The cut-out corners of Figure 2A represent, more specifically, the interconnecting element 962 having elements 315 and 316 connected to the metal contact pad 952. Figure 2E also represents the metal grid layers 940 of the solar cell 900.

[72] Figure 2F shows the attachment of an interconnecting element 960 to the pad of metallic contact 952. The interconnecting element 960 is a rectangular clamp having a first flat end 961 welded to the metallic contact 952, a second part 962 connected to the first end 961 and extending over the surface of the solar cell, and a third part 963 connected to the second part 962 and of sinuous shape, the second end 964 extending under the bottom of the solar cell and is designed and oriented so that its flat upper surface can be welded to the bottom of the metallic contact 911 of an adjacent solar cell 800, as shown in Figure 21.

[73] Figure 2G is a top view of the solar cell of Figure 2A, after fixation of a cover glass 981 on top of the solar cell 900, thus forming a cell-interconnect-cover glass (CIC). Figure 2G also shows the interconnecting elements 962 and 972.

[74] Figure 2H is a cross-sectional view of the solar cell in Figure 2F, after the The process of attaching a 981 cover glass to the top of the solar cell using an adhesive 980. The 981 cover glass typically has a thickness of approximately 4 mils. While the use of a cover glass is desirable for various environmental conditions and applications, it is not necessary for all implementations, and additional layers or structures can also be used to provide extra support or environmental protection for the solar cell.

[75] Figure 21 is a cross-sectional view of the solar cell in Figure 2H, which is at present designated cell 300, after the next step of alignment with the edge of an adjacent similar solar cell 800, in the process of manufacturing a panel or 15 of an interconnected strip of solar cells. The similar solar cell 800 comprises layers 811, 812 to 836, 838 and 840 similar to layers 911, 912, ... to 936, 938 and 940, respectively, of the solar cell 300. A cover glass 881 is fixed by an adhesive 880 to the solar cell 800, in a similar manner to the solar cell 300.

[76] Figure 3 is a flowchart showing a process according to one embodiment of the present invention. Certain embodiments of the invention may include one or more of the steps of wafer fabrication (101), back face metallization (102), front face lithography and metal deposition (103), mesa lithography and etching (104), anti-reflective coating (ARC) deposition (105), cell cutting from wafer (106), cell testing (107), interconnect fixing and configuration and fixing of bypass diodes (108), fixing of cover glass to form a CIC (109), strip configuration formation (110), strip interconnect formation (111), CIC strip bonding to substrate (112), panel circuit configuration and wiring (113), diode configuration locking (114), terminal wiring (115) and functional testing (116).

[77] In certain embodiments of the present invention, one or more of the The aforementioned steps of the process can be carried out by an automated process. Exemplary automated processes for some of the steps are discussed in more detail below. However, the present invention may include alternative automated processes known in the art for each step of the process. Furthermore, the exemplary automated processes discussed here for carrying out one step of the process can be used to carry out other steps not explicitly discussed here. In some embodiments, a series of the described process steps can be carried out using one or more automated processes. In some embodiments, all of the aforementioned process steps can be carried out using one or more automated processes.

[78] In some embodiments, the automated process may use a robot (e.g. pick and place assembly tools) to perform a classic manual process.

[79] In certain embodiments, a laser cable welding machine can can be used to fix interconnections to one or more solar cells.

[80] In certain embodiments, the automated process or processes may use Machine vision. Machine vision can encompass image-based automated inspection and analysis for applications such as automated inspection, process control, and robot guidance. While conventional (2D visible light) imaging is most commonly used for machine vision, alternatives include imaging of various infrared bands, line scanning imaging, 3D surface imaging, and X-ray imaging. The most widely used 3D imaging technique is triangulation-based scanning, which utilizes the motion of the product or image during the imaging process. Other 3D techniques used for machine vision include time-of-flight, grid-based, and stereoscopic imaging.

[81] For computer vision, the imaging device (e.g., a camera) can be The image processing unit can be separate from, or combined with, the main image processing unit, in which case the combined unit might be a smart camera or a smart sensor. If separate, the connection can be made using specialized intermediate hardware such as a data acquisition card via a standardized or common interface. Computer vision can also utilize digital cameras capable of direct connections (without a data acquisition card) to a computer.

[82] Although the vast majority of computer vision applications use imaging In contrast to two-dimensional applications, computer vision using 3D imaging represents a growing alternative. One method uses grid-based systems employing a pseudo-statistical light system. Another method for generating a 3D image involves laser triangulation, where a laser beam is projected onto the surfaces of an object, and the resulting deviation is used to calculate its shape. In computer vision, this is achieved through scanning, either by moving the workpiece or by moving the camera and laser imaging system. Stereoscopic vision can be used in special cases involving unique features present in both views from a pair of cameras.

[83] Solar cell wafers can be prepared by automated processes of deposition of III-V compound semiconductor layers and other layers (by For example, an anti-reflective coating (ARC) can be applied to a substrate to create a wafer. These processes, which can be easily automated, include, for example, metal-organic precursor chemical vapor deposition (MOCVD), which is well-established in the field. Metallization of the back side of a cell can be achieved, for example, by evaporation or electrodeposition onto a polyimide layer (e.g., a KAPTON® layer).

[84] The features of such grid lines and mesas can be formed on the front faces of the discs using classic techniques such as lithography, metal deposition and engraving techniques, all of which can be easily automated using, for example, machine vision.

[85] Particularly suitable solar cell configurations for assembly with automated processes include those described in US patent applications No. 14 / 592 519, filed January 8, 2015; 14 / 719 911, filed May 21, 2015; 14 / 729 412, filed June 3, 2015; and 14 / 729 422, filed June 3, 2015.

[86] One or more solar cells can be formed from a wafer in using conventional techniques such as cutting or tracing. The size and shape of the solar cells can vary as required for specific applications, as described, for example, in US patent application No. 14 / 592 519, filed on January 8, 2015. Cutting or tracing solar cells from a wafer can be automated, particularly using machine vision.

[87] The functionality of one or more solar cells can be tested by a conventional automated testing equipment.

[88] The interconnections can be attached to one or more solar cells in using, for example, automated brazing or laser welding equipment.

[89] In some embodiments, one end of the interconnections may have parallel openings, and interconnections can be connected, for example, by using a parallel capillary welding tool.

[90] In some embodiments, all the electrical components of the panel of solar cells can be encapsulated with CV-grade silicone, which can be It is used to mount multi-cell cover glass, or as a surface for applying advanced coatings such as cover glass replacement (CGR) or radiation-resistant coatings. This approach can produce a panel that is electrically isolated, can mitigate high-voltage arcing problems, can eliminate cracking, and appears to minimize the need for expensive inter-cell filling, and can provide electrostatic cleanliness.

[91] The application of silicone to the solar cells and to the cover glass has Typically, this has been achieved using a pattern screen printing process or squeegeeing approaches. These processes require additional materials and a process associated with matrix design and production, as well as the uneconomical nature of manual mixing and application. These processes are inherently uneconomical and labor-intensive, resulting in high costs and low throughput. The approach described here concerns the low-cost, high-precision application of a silicone adhesive to solar cell assemblies with standardized substrates.

[92] In some embodiments, silicone can be applied to the cell solar energy using, for example, an automated Asymtek machine with visual recognition for maximum accuracy.

[93] A cover glass can be attached to each solar cell to form a Cell-interconnect-cover glass (CIC) assembly can be performed using automated processes. For example, in some embodiments, the CIC assembly process can be carried out by implementing automated assembly and lamination. After large-area or precision operations, a temporary support can be attached in a component placement machine. Through computer visual recognition of placement points, a digitally controlled component placement machine can pick up the large-area solar cell cover glass from a stack, place it onto the uncrosslinked silicone applied in the previous step, which can then be crosslinked to form the CIC.

[94] In some embodiments, a similar component placement step can be implemented to load a wiring machine and perform the final placement of sub-modules onto any suitable number of solar panel substrates, such as flexible membrane or rigid composite panels. Such automated processes 19 can reduce or eliminate manual and time-consuming process operations.

[95] The CICs can be positioned and placed on a support in an automated manner, for example by a pick and place assembly tool to form a strip conformation of CIC as described for example, in US patent applications No. 14 / 719 911, filed on May 21, 2015, and 14 / 729 412, filed on June 3, 2015. Bypass and blocking diodes can be configured by similar methods.

[96] The solar cell in a strip can be interconnected using, for example, a standard automated equipment for wiring such as an automated thermosonic wiring machine and also, as described for example in US patent application No. 14 / 719 911, filed on May 21, 2015. -

[97] Band configurations or interconnected band configurations of the Solar cells are positioned and placed on a support in an automated manner, for example by a pick and place assembly tool as described, for example, in US patent applications No. 14 / 719 911, filed on May 21, 2015, and 14 / 729 412, filed on June 3, 2015. In some embodiments, strip configurations or interconnected strip configurations of solar cells may be bonded to the substrate by the automatic application of pressure and / or heat and interconnected in a manner similar to that discussed above.

[98] The configuration and wiring of a panel circuit and terminals can be carried out using conventional automated wiring equipment.

[99] The functionality test of the solar cell panel can be carried out by Automated processes similar to those discussed above are used for testing individual solar cells. For example, 5-cell submodules have been fabricated using the processes described here. Submodule testing includes electrical continuity, grounding, and insulation testing. The submodules are subjected to a thermal cycle from -120°C to +120°C to represent typical LEO (Low Earth Orbit) conditions; from -180°C to +180°C to represent typical GEO (Geostationary Earth Orbit) conditions; and, in a related program, to high-voltage plasma environments as initial qualification for low Earth orbit environments. 20 All tests show good performance and reliability for the solar cell strips before and after exposure to these environments.

[100] An economic analysis of the benefits of linking processes and engineering Automated assembly is performed to quantify the benefits in reducing the costs of sub-modular blocks of solar cell strips. The data in Table 1 demonstrate the significant reduction in integration costs. The results, summarized in Table 1, are comparative only and do not necessarily represent a specific absolute price for a photovoltaic array or panel in a particular quantity. Labor cost estimates were made based on all labor-related costs, including hypothetical overhead, but do not take into account team structures and potential alternative cell manufacturing. Labor costs do not account for the lower level of expertise that can be implemented with fully automated equipment compared to the high level of expertise often required for manual or semi-automated assembly.

[101] TABLE 1: Cost projections for an automated approach versus a traditional approach

[102]

[103] Material and production cost Traditional integration Automated integration THINS Material $ / Watt Material $ / Watt Cell 250.00 Cell 250.00 Interconnect film 20.73 Gold cable 0.48 Individual cover glass 5.12 Large area cover glass 6.11 Adhesive 3.70 Adhesive 1.55 Diode 12.50 Diode 12.50 Cable 1.00 Terminal strip 12.72 Consumables, template, etc. 3.00 Flexible Harness 1.96 Total Materials: 296.05 Total Materials: 285.32 Integration Process $ / Watt Integration Process $ / Watt Additional Cost for a Senior Technician 25% Additional Cost for a Senior Technician 0% Interconnect Soldering to Pick and Place Cells, Diode Cells and Terminal Strips Interconnect Soldering between j 5 Wiring and Soldering 3 Automated Interconnect Cells Individual Silicone 7 Automated Encapsulation 4 Individual Cover Glass 8 Application of Cover Glass or CGR 3 Mask and Silicone Applicationj 12 Automated silicone application 3 Transfer tool 5 Automated "Pick and Place" of sub-module i 3 Sheet tiling 5 Press curing in a vacuum bag 3 Material deposition 8 Cleaning (clean process by precise application) 0 Bagging and curing 8 Cleaning 18 Panel wiring 12 Automated solder placement 5 Soldering 5 Solder reflux in oven 3 Sealing: 25 Sealing (multi-cell glass requires less) 10 Documentation and inspection 35 Documentation and inspection 15 Labor cost $ / Watt: 160 Labor cost $ / Watt: 160 Yield: 85% Yield: 97.5% Integrated cost $ / Watt: 537 Integrated cost $ / Watt: 350 *Costs are related, charged at a borrowed overhead rate, and do not take into account production quantities and skill level potentially lower required for the operation of automated equipment. Figure 4 is a perspective view of a 200 metal honeycomb structure, which can be used for mounting a support.

[104] Figure 5 is a cross-sectional view of an aluminum 200 honeycomb substrate with a carbon composite sheet 201 attached to it. In some embodiments, a double-sided adhesive film can be positioned on the upper surface of the face sheet, and the lower surface of the adhesive film can be bonded to the upper surface of the face sheet, for example, by co-crosslinking. In some embodiments, a series of layers of carbon composite sheets can be embedded in a matrix of a cyanate ester adhesive. The polyimide can then be placed on top, and the entire stack is co-crosslinked.

[105] In some embodiments, a sequence of solar cell assemblies can be positioned on the upper surface of the adhesive film, and each solar cell assembly in the sequence can be sequentially bonded to a predefined region of the upper surface of the adhesive film, for example, by automatically applying pressure and / or heat. In some embodiments, the predefined region contains a self-adhesive layer, and there is no adhesive on the other regions of the upper surface of the facing sheet.

[106] Figure 6 is a cross-sectional view of an aluminium 200 honeycomb substrate with carbon composite face sheet 201 fixed to the aluminum honeycomb substrate 200, and the co-crosslinked polyimide substrate 202 fixed to the carbon composite face sheet 201.

Claims

Demands 1. A method for manufacturing a multi-junction solar cell panel, comprising one or more of the following steps: provision of a wafer using a metal-organic precursor chemical vapor deposition (MOCVD) reactor; fixing the interconnections (962, 972) to the solar cell(s) (900); fixing a cover glass (980) on each solar cell in order to form a cell-interconnect-cover glass (CIC); formation of a CIC band configuration; interconnection of CIC band configurations; link of strip configurations or interconnected strip configurations on a substrate (912); panel circuit configuration and wiring; configuration of a blocking diode; wiring of a first terminal and a second terminal of first and second polarities, respectively, for the solar cell panel; and testing the functionality of the solar cell panel; where at least one of the steps of the process is carried out by an automated process; and where the process includes one or more of the following characteristics: (i) at least one of the automated processes uses a pick and place assembly tool; a wiring machine or a laser welding machine to fix the interconnections (962, 972) onto one or more solar cells (900); automatic vapor deposition equipment; automatic metal plating equipment; automatic lithography techniques; automatic engraving techniques; automatic cutting techniques; automatic testing equipment; automatic brazing or laser welding equipment; automatic application equipment; automatic wiring equipment; and / or an automatic application of pressure and / or heat; ii) the solar cells (900) each have a surface area of ​​less than 5 cm²; and / or iii) Solar cells (900) are III-V compound semiconductor multijunction solar cells prepared from manufactured wafers, and the manufacture of the wafers comprises: the provision of a metal-organic precursor chemical vapor deposition (MOCVD) system configured to independently control the flow rate of source gases for gallium, indium, aluminium and arsenic; the selection of a reaction time and temperature and a flow rate for each source gas to form a continuously graded interlayer arranged on the lower subcell, where the source gas for indium is trimethylindium (InMes), the source gas for gallium is trimethylgallium (GaMes), the source gas for arsenic is arsine (AsHa), and the source gas for aluminum is trimethylaluminum (AbMee); and / or iv) the panel is flexible and is composed of a poly(4,4'-oxydiphenylene-pyromellitimide) material.

2. A method according to claim 1, wherein the method comprises one or more of the following steps, carried out in particular using an automated process: metallization of the back face of the disc; creation of a pattern by lithography and deposition of metal on the front face of the disc; formation of a mesa on the front face of the disc by lithography and engraving; application of an anti-reflective coating (RAR) on the disc; cutting one or more solar cells (900) from the wafer; testing the functionality of the solar cell(s) (900).

3. A method according to any one of the preceding claims, wherein the automated process uses machine vision.

4. A method according to any one of the preceding claims, wherein at least one of the automated processes uses a robot.

5. A method according to any one of the preceding claims, wherein the panel is flexible and is composed of a poly(4,4'-oxydiphenylene-pyromellitimide) material.

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