Visual inspection method for photovoltaic modules

Abstract

This application relates to the field of photovoltaic detection technologies, and particularly to a visual detection method for photovoltaic modules. The photovoltaic module includes solar cells and a film strip, and the length of the film strip is less than the cell gap of the solar cells or the string gap length of the cell string; the visual detection method includes: turning on the first light source above, and the image collector records the first coordinate and the second coordinate of the intersection point of the end edges of the film strip; turning on the second light source below, and recording the third coordinate and the fourth coordinate of the overlapping points of the solar cells, the end of the film strip, and the cell gap or the string gap; analyzing the differences between the first coordinate and the third coordinate, and between the second coordinate and the fourth coordinate, and the difference is the overlapping distance. In the visual detection method of this application, the setting of the shortened film strip, in cooperation with the first light source and the second light source, can respectively collect the edge coordinates of the solar cells and the film strip, and then obtain the overlapping distance, and photovoltaic modules with a smaller overlapping distance or where both sides of the film strip do not completely cover the cell gap or the string gap can be selected for renovation.

Description

Technical Field

[0001] This application relates to the field of photovoltaic detection technology, and particularly to a visual detection method for photovoltaic modules.

Background Art

[0002] In recent years, researchers have been committed to the efficient conversion of solar energy into electrical energy based on the photovoltaic effect. Currently, in order to make full use of the effective usage area in photovoltaic modules, people have conducted detailed analysis and research on the non-cell area in photovoltaic modules, and found that most of the light incident on the gaps between cells in the photovoltaic module undergoes specular reflection, is reflected outside the module, or passes through the module to reach the ground. The gaps between cells and between cell strings essentially occupy a part of the surface area of the photovoltaic module, and the gaps cannot participate in energy conversion, resulting in the waste of sunlight received by this part of the surface area and reducing the photoelectric conversion efficiency of the photovoltaic module.

[0003] To solve this problem, a reflective film strip can be attached to the photovoltaic backplane, which is disposed opposite to the gaps between cells and between cell strings. In the prior art, there are mainly two film-attaching designs for the gap film-attaching assembly: one is that the film strip lengths between all strings / sheets can completely cover the entire string / sheet gap; the other is that the film strip length between sheets is complete, while the film strips between strings are all set in the form of being half a cell short. For these two design methods, it is impossible to observe the width of the overlapping part between the cell and the film strip at any site through conventional visual recognition methods, which easily causes problems such as too small an overlapping distance between the film strip and the cell or light leakage, reducing the lamination yield of the photovoltaic module.

Summary of the Invention

[0004] In view of this, this application provides a visual detection method for photovoltaic modules. By setting the two ends of the film strip to be shorter relative to the sheet gap between cells or the string gap between cell strings, and cooperating with the first light source and the second light source arranged up and down, photovoltaic modules with a relatively small overlapping distance between the two or light leakage caused by the two sides of the film strip not completely covering the sheet gap or string gap can be selected for renovation, improving the lamination yield of the photovoltaic module.

[0005] In a first aspect, this application provides a visual detection method for photovoltaic modules. The photovoltaic module includes a plurality of cells and a plurality of film strips; the film strips are disposed opposite to the sheet gaps formed between the cells or the string gaps formed between cell strings, and the length of the film strip is less than the length of the sheet gap or the string gap; the visual detection method includes the following steps:

[0006] The first light source located above the photovoltaic module is turned on, and the image collector records the first coordinate and the second coordinate of the intersection of the end edges of the film strip.

[0007] The second light source located below the photovoltaic module is turned on, and the image collector records the third coordinate and the fourth coordinate of the overlapping points of the edge of the battery cell, the end of the film strip, and the sheet gap or the string gap.

[0008] The image collector analyzes the differences between the first coordinate and the third coordinate, and between the second coordinate and the fourth coordinate in the width direction of the sheet gap or the string gap. Among them, the difference is the overlapping distance between the film strip and the battery cell.

[0009] In a feasible embodiment, the vertical distance between the first light source and the film strip is 50 mm to 500 mm.

[0010] In a feasible embodiment, the luminous intensity of the first light source is 1000 Lm to 20000 Lm.

[0011] In a feasible embodiment, the vertical distance between the second light source and the battery cell is 1 mm to 200 mm.

[0012] In a feasible embodiment, the luminous intensity of the second light source is 1000 Lm to 20000 Lm.

[0013] In a feasible embodiment, the length of the end of the sheet gap or the string gap not covered by the film strip is 0.5 mm to 200 mm.

[0014] In a feasible embodiment, the vertical distance from the image collector to the battery cell is 100 mm to 600 mm.

[0015] In a feasible embodiment, the photovoltaic module includes a photovoltaic backplane; a plurality of film strips are provided on the photovoltaic backplane, and the sheet gaps formed between the film strips and the battery cells or the string gaps formed between the battery strings are arranged oppositely; the width of the film strip is greater than the width of the sheet gap or the string gap, and at least part of both ends of the film strip does not cover the sheet gap or the string gap along the length direction of the sheet gap or the string gap.

[0016] In a feasible embodiment, the width ratio of the film strip to the sheet gap or the string gap is (2.5 to 3.5):1.

[0017] In a feasible embodiment, along the width direction of the sheet gap or the string gap, the overlapping distance between the film strip and the battery cell is 0.01 mm to 10 mm.

[0018] After adopting the above technical solutions, the beneficial effects are:

[0019] The visual detection method provided by this application, through the setting that the distance between the two ends of the film strip on the photovoltaic module is shortened relative to the gap between the cells or the gap between the cell strings, and in cooperation with the first light source and the second light source arranged up and down, the image collector can respectively collect the coordinates of the intersection points of the end edges of the film strip, and the overlapping point coordinates of the edge of the cell, the end of the film strip, and the cell gap or string gap. Furthermore, the stacking distance between the cell and the light-emitting film strip can be calculated, so as to select the photovoltaic modules with a relatively small overlapping distance between the two or light leakage caused by the incomplete coverage of the gap on both sides of the film strip for renovation, thereby improving the lamination yield of the photovoltaic module.

Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions of the embodiments of this application, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a schematic structural diagram of the photovoltaic module provided by this application;

[0022] Figure 2 It is a schematic structural diagram of the film strip covering the cell gap or string gap of the photovoltaic module provided by this application;

[0023] Figure 3 It is a flowchart of the visual detection method provided by this application;

[0024] Figure 4 is Figure 2 an enlarged schematic diagram of A in

[0025] Figure 5 is Figure 2 an enlarged schematic diagram of B in

[0026] Reference numerals:

[0027] 1 - Photovoltaic glass;

[0028] 2 - First encapsulant film;

[0029] 3 - Cell;

[0030] 311 - Cell gap; 312 - String gap; 32 - Third coordinate; 33 - Fourth coordinate; 34 - Second edge position information;

[0031] 4 - Second encapsulant film;

[0032] 5 - Photovoltaic backsheet;

[0033] 51 - Film strip; 511 - First coordinate; 512 - Second coordinate; 513 - First edge position information.

Specific Embodiments

[0034] For a better understanding of the technical solution of the present application, the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0035] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0036] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms of "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0037] It should be understood that the term " / and" used herein is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0038] In recent years, researchers have been committed to the efficient conversion of solar energy into electrical energy based on the photovoltaic effect. At present, in order to make full use of the effective use area in the photovoltaic module, people have made a detailed analysis and research on the non-cell area in the photovoltaic module, and found that most of the light incident on the gaps between the cells in the photovoltaic module undergoes positive reflection, is reflected outside the module, or passes through the module to reach the ground. The gaps between the cells and between the cell strings substantially occupy a part of the surface area of the photovoltaic module, and the gaps cannot participate in energy conversion, resulting in the waste of the sunlight received by this part of the surface area and reducing the photoelectric conversion efficiency of the photovoltaic module.

[0039] To solve this problem, a reflective film strip can be attached to the photovoltaic backplane and disposed opposite to the gaps between the cells and between the cell strings. In the prior art, there are mainly two film pasting designs for the gap film pasting assembly: one is that the film strip lengths between all strings / sheets can completely cover the entire string / sheet gap; the other is that the film strip length between sheets is complete, while the film strips between strings are all set in the form of being half a cell shorter. For these two design methods, it is impossible to observe the width of the overlapping part of the cell and the film strip at any site through the conventional visual recognition method, which is likely to cause the problem of too small overlapping distance between the film strip and the cell or light leakage, reducing the lamination yield of the photovoltaic module.

[0040] In view of this, the present application provides a visual inspection method for a photovoltaic module. Figure 1The structural schematic diagram of the photovoltaic module provided by this application is as follows Figure 1 As shown, the photovoltaic module includes a plurality of cell sheets 3 and a plurality of film strips 51; the film strips 51 are disposed opposite to the sheet gaps 311 between the cell sheets 3 or the string gaps 312 between the cell strings formed between the cell sheets 3, and the length of the film strip 51 is less than the length of the sheet gap 311 or the string gap 312; the visual inspection method includes the following steps:

[0041] The first light source located above the photovoltaic module is turned on, and the image collector records the first coordinate 511 and the second coordinate 512 of the end edge intersection points of the film strip 51;

[0042] The second light source located below the photovoltaic module is turned on, and the image collector records the third coordinate 32 and the fourth coordinate 33 of the overlapping points of the edge of the cell sheet 3, the end of the film strip 51, and the sheet gap 311 or the string gap 312;

[0043] The image collector analyzes the differences between the first coordinate 511 and the third coordinate 32, and between the second coordinate 512 and the fourth coordinate 33 in the width direction of the sheet gap 311 or the string gap 312. Among them, the difference is the overlapping distance between the film strip 51 and the cell sheet 3.

[0044] In the above solution, the visual inspection method is set by shortening the film strip 51 at both ends of the photovoltaic module relative to the sheet gap 311 between the cell sheets 3 or the string gap 312 between the cell strings, and cooperating with the first light source and the second light source arranged up and down. The image collector can respectively collect the coordinates of the end edge intersection points of the film strip 51, and the overlapping point coordinates of the edge of the cell sheet 3, the end of the film strip 51, and the sheet gap 311 or the string gap 312, and then calculate the stacking distance between the cell sheet 3 and the light-emitting film strip, so as to select the photovoltaic modules with a smaller overlapping distance between the two or light leakage caused by the incomplete coverage of the gaps on both sides of the film strip 51 for renovation, and improve the lamination yield of the photovoltaic module.

[0045] In some embodiments, the photovoltaic module components detected by the visual inspection method include a photovoltaic glass 1, a first encapsulant film 2, multiple groups of solar cell strings, a second encapsulant film 4, and a photovoltaic backsheet 5. The solar cell strings include a plurality of cell sheets 3 connected in series. The photovoltaic glass 1, the first encapsulant film 2, multiple groups of solar cell strings, the second encapsulant film 4, and the photovoltaic backsheet 5 are laminated to obtain the photovoltaic module.

[0046] Specifically, multiple groups of solar cell strings in the photovoltaic module are arranged at intervals, and a string gap 312 is formed between adjacent solar cell strings. Among them, the solar cell string includes a plurality of solar cells 3, and adjacent solar cells 3 are connected in series through a conductive connecting member (such as a welding wire or a welding tape). One end of the conductive connecting member is welded to the back electrode of one of the solar cells 3, and the other end of the conductive connecting member is welded to the front electrode of another solar cell 3, so that a cell gap 311 is formed between adjacent solar cells 3.

[0047] It should be noted that the solar cell 3 used in this application can be a single-sided light conversion solar cell or a double-sided light conversion solar cell. Single-sided light conversion means that the solar cell 3 can only receive light from one side and convert the light into electric power; the double-sided solar cell 3 means that the solar cell 3 can receive light from both sides and convert the light into electric power, that is, the solar cell 3 can not only receive direct sunlight from the front to convert it into electric power, but also receive light such as reflected light or scattered light from the ground from the back, thereby improving the power generation efficiency of the photovoltaic module. It can also be a solar cell 3 in other light conversion areas, and the type of the solar cell 3 can be selected according to actual needs, which is not limited here.

[0048] Since the solar cell 3 is very fragile and is easily damaged when pressed, the photovoltaic glass 1 and the photovoltaic backplane 5 cannot be directly attached to it. Therefore, the first adhesive film 2 and the second adhesive film 4 need to play a bonding role in the middle. In actual use, the first adhesive film 2 and the second adhesive film 4 are used to encapsulate the solar cell strings arranged at intervals. Specifically, the first adhesive film 2, the solar cell strings and the second adhesive film 4 are stacked to obtain a composite body, and then the composite body is heated to a certain temperature so that the first adhesive film 2 and the second adhesive film 4 are melted and bonded to the solar cell 3.

[0049] It should be noted that the first adhesive film 2 and the second adhesive film 4 used in this application can be ethylene-vinyl acetate copolymer (EVA) adhesive film, polyethylene octene co-elastic body (POE) adhesive film or polyethylene terephthalate (PET) adhesive film respectively. It can also be other types of adhesive films, which can be selected according to actual needs and are not limited here. Preferably, the first adhesive film 2 and the second adhesive film 4 used in this application are EVA adhesive films. The EVA adhesive film has no viscosity at room temperature, has good flexibility, transparency and surface gloss, stable chemical properties, good anti-aging and ozone resistance, is non-toxic, and undergoes melting bonding and cross-linking curing under certain conditions of hot pressing. The cured adhesive film has excellent light transmittance, bonding strength, thermal stability, airtightness and anti-aging performance, and will not affect the light conversion performance of the photovoltaic module when encapsulating multiple groups of solar cell strings.

[0050] The photovoltaic glass 1 is disposed on the side of the first adhesive film 2 away from the solar cell 3. The photovoltaic glass 1 is also called "photoelectric glass" and has good light transmittance and high hardness. After covering the first adhesive film 2, it can adapt to a large day-night temperature difference and harsh weather environment, playing a protective role for the solar cell 3. The photovoltaic glass 1 used in this application can be ultra-white embossed photovoltaic glass, ultra-white processed float glass, TCO glass, etc., or other types of photovoltaic glass 1, which can be selected according to actual needs and are not limited herein.

[0051] The photovoltaic backplane 5 is disposed on the side of the second adhesive film 4 away from the solar cell 3. The photovoltaic backplane 5 also plays a role in protecting and supporting the solar cell 3, and has good weather resistance, water resistance, corrosion resistance, insulation, etc. It can not only isolate the photovoltaic module from the surrounding photovoltaic environment, but also effectively protect and support the solar cell 3, thereby increasing the impact resistance of the photovoltaic module. The photovoltaic backplane 5 used in this application can be a double-sided fluorine film backplane, a single-sided fluorine film backplane, a fluorine-free backplane, etc., which can be selected according to actual needs and are not limited herein.

[0052] In order to improve the utilization rate of sunlight by the photovoltaic module, a plurality of film strips 51 are further provided on the photovoltaic backplane 5. Figure 2 It is a schematic structural diagram of the film strip covering gap or string gap of the photovoltaic module provided by this application. As Figure 2 shown, the sheet gap 311 formed between the film strip 51 and the solar cell 3 or the string gap 312 formed between the solar cell strings are arranged opposite to each other, and can be used to reflect the sunlight incident on the backplane back to the solar cell 3. Specifically, after multiple groups of solar cell strings are arranged, a plurality of sheet gaps 311 arranged longitudinally are formed between the solar cells 3, and a plurality of string gaps 312 arranged transversely are formed between the solar cell strings. The sheet gaps 311 or string gaps 312 of the photovoltaic module obtained after the final lamination process are in a grid shape, that is, the film strips 51 on the photovoltaic backplane 5 are also arranged in a grid shape, so that the sheet gaps 311 or string gaps 312 can still participate in the conversion of sunlight energy.

[0053] Further, the width ratio of the film strip 51 to the sheet gap 311 or the string gap 312 is (2.5 to 3.5):1. Optionally, the width ratio of the film strip 51 to the sheet gap 311 or the string gap 312 can specifically be 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3.0:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, etc., or other values within the range, which can be selected according to actual needs and are not limited herein. If the width ratio of the film strip 51 to the sheet gap 311 or the string gap 312 is too small, that is, the film strip 51 cannot effectively cover the sunlight irradiation area passing through the sheet gap 311 or the string gap 312, the utilization rate of sunlight is low, and the light conversion efficiency of the photovoltaic module is low; if the width ratio of the film strip 51 to the sheet gap 311 or the string gap 312 is too large, that is, the film strip 51 has a large coverage area and the utilization rate of sunlight is high, but the manufacturing cost of the photovoltaic module increases.

[0054] During actual use, the laminated photovoltaic glass 1, the first adhesive film 2, multiple groups of solar cell strings, the second adhesive film 4, and the photovoltaic backplane 5 are placed in a laminator. The air inside the module is pumped out through vacuuming, and then heated to melt the first adhesive film 2 and the second adhesive film 4 to bond the battery, the glass, and the photovoltaic backplane 5 together to obtain a photovoltaic module.

[0055] It should be noted that since sunlight passes through the sheet gap 311 or the string gap 312 from all directions, the area of sunlight irradiated on the backplane is larger than the area of the gap. In order to make better use of the sunlight passing through the sheet gap 311 or the string gap 312, the width of the film strip 51 used in this application is greater than the width of the sheet gap 311 or the string gap 312 of the photovoltaic module. Therefore, during the lamination process, it is necessary to detect the overlapping distance between the film strip 51 and the battery cell 3 along the width direction, and select the photovoltaic modules with a smaller overlapping distance between the two or those with light leakage caused by the two sides of the film strip 51 not completely covering the sheet gap 311 or the string gap 312 for renovation to improve the lamination yield of the photovoltaic module.

[0056] Further, in order to enable the visual inspection process to proceed normally, the length of the film strip 51 used in this application is less than the length of the sheet gap 311 or the string gap 312 of the photovoltaic module, that is, at least part of the two ends of the film strip 51 does not cover the sheet gap 311 or the string gap 312. During use, the film strip 51 covers the grid-shaped sheet gap 311 or the string gap 312 of the photovoltaic module along the width direction, and the two ends of the film strip 51 along the length direction do not completely cover the grid-shaped sheet gap 311 or the string gap 312, that is, the side length of the grid structure formed by the film strip 51 finally is less than the side length of the grid structure formed by the sheet gap 311 or the string gap 312 of the photovoltaic module.

[0057] Figure 3 This is the flowchart of the visual inspection method provided by this application, asFigure 3 As shown in the figure, the visual inspection method includes the following steps:

[0058] Step S10: The photovoltaic backplane 5 of the photovoltaic module is placed face up on the workbench, the first light source located above the photovoltaic module is turned on, and the image collector records the first coordinate 511 and the second coordinate 512 of the intersection of the end edges of the film strip 51.

[0059] Step S20: The second light source located below the photovoltaic module is turned on, and the image collector (CMOS) records the third coordinate 32 and the fourth coordinate 33 of the overlapping points of the edge of the battery cell 3, the end of the film strip 51, and the cell gap 311 or the string gap 312.

[0060] Step S30: The image collector analyzes the differences between the first coordinate 511 and the third coordinate 32, and between the second coordinate 512 and the fourth coordinate 33 in the width direction of the cell gap 311 or the string gap 312. Here, the difference is the overlapping distance between the film strip 51 and the battery cell 3.

[0061] In step S10, the photovoltaic backplane 5 of the photovoltaic module is face up, that is, during the detection process, Figure 4 is Figure 2 The enlarged schematic diagram of A in, as Figure 4As shown, the film tape 51 is located above the battery cell 3. When the first light source above the workbench is turned on, the first light source can reveal the end edges of the film tape 51 in the width direction. During the irradiation process, the vertical distance between the first light source and the film tape 51 is 50 mm to 500 mm, and the luminous intensity of the first light source is 1000 Lm to 20000 Lm. Optionally, the vertical distance between the first light source and the film tape 51 can specifically be 50 mm, 100 mm, 150 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, 450 mm, 500 mm, etc., and the luminous intensity of the first light source can specifically be 1000 Lm, 3000 Lm, 5000 Lm, 7000 Lm, 9000 Lm, 11000 Lm, 13000 Lm, 15000 Lm, 17000 Lm, 20000 Lm, etc., or other values within the range, which can be selected according to actual needs and are not limited here. If the vertical distance between the first light source and the film tape 51 is too small or the luminous intensity of the first light source is too large, the brightness on the film tape 51 is too high, and during the irradiation process, the light is likely to penetrate the film tape 51 and then irradiate on the battery cell 3, causing the edge of the film tape 51 to coincide with the battery cell 3, which affects the acquisition process of the first coordinate 511 and the second coordinate 512 of the intersection of the end edge of the film tape 51 by the image collector; if the vertical distance between the first light source and the film tape 51 is too large or the luminous intensity of the first light source is too small, the brightness on the film tape 51 is too low, the edge of the film tape 51 is not obvious, and the image collector cannot acquire the correct first coordinate 511 and the second coordinate 512 of the intersection of the end edge of the film tape 51.

[0062] In step S20, when the second light source under the workbench is turned on, the edge of the battery cell 3 can be revealed by the second light source. During the irradiation process, the vertical distance between the second light source and the battery cell 3 is 1 mm to 200 mm, and the luminous intensity of the second light source is 1000 Lm to 20000 Lm. Optionally, the vertical distance between the second light source and the battery cell 3 can specifically be 1 mm, 20 mm, 40 mm, 60 mm, 80 mm, 100 mm, 120 mm, 140 mm, 160 mm, 180 mm, 200 mm, etc., and the luminous intensity of the second light source can specifically be 1000 Lm, 3000 Lm, 5000 Lm, 7000 Lm, 9000 Lm, 12000 Lm, 14000 Lm, 16000 Lm, 18000 Lm, 20000 Lm, etc., or other values within the range, which can be selected according to actual needs and are not limited herein. If the vertical distance between the second light source and the battery cell 3 is too small or the luminous intensity of the second light source is too large, the brightness on the battery cell 3 is too high, and the light passes through the chip gap 311 or the string gap 312 and then irradiates onto the image collector, affecting the position acquisition process of the image collector, resulting in inaccurate acquisition results of the third coordinate 32 and the fourth coordinate 33 of the overlapping point of the edge of the battery cell 3, the end of the film strip 51, and the chip gap 311 or the string gap 312; if the vertical distance between the second light source and the battery cell 3 is too large or the luminous intensity of the second light source is too small, the brightness of the battery cell 3 is too low, the edge of the battery cell 3 is not obvious, and the image collector cannot acquire the correct third coordinate 32 and fourth coordinate 33 of the overlapping point of the edge of the battery cell 3, the end of the film strip 51, and the chip gap 311 or the string gap 312.

[0063] In step S30, how does the image collector analyze the differences between the first coordinate 511 and the third coordinate 32, and between the second coordinate 512 and the fourth coordinate 33 in the width direction of the chip gap 311 or the string gap 312?

[0064] In a photovoltaic module with a lamination yield meeting the production requirements, along the length direction of the chip gap 311 or the string gap 312, the overlapping distance between the film strip 51 and the battery cell 3 is 0.01 mm to 10 mm. Optionally, the overlapping distance between the film strip 51 and the battery cell 3 can specifically be 0.01 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc., or other values within the range, which can be selected according to actual needs and are not limited herein. If the overlapping distance between the film strip 51 and the battery cell 3 is too large, the utilization rate of sunlight is high, but the preparation cost of the photovoltaic module increases; if the overlapping distance between the film strip 51 and the battery cell 3 is too small, the utilization rate of sunlight is low, and the light conversion efficiency of the photovoltaic module is low.

[0065] The above visual detection method, by setting the relative film gap 311 or string gap 312 at both ends of the film strip 51 to be shortened, and cooperating with the first light source and the second light source arranged up and down, the image collector can respectively collect the coordinates of the intersection points of the end edges of the film strip 51, and the overlapping point coordinates of the edge of the battery cell 3, the end of the film strip 51, and the film gap 311 or string gap 312, and then calculate the stacking distance between the battery cell 3 and the light-emitting film strip. In another alternative technical solution, the visual detection method provided in this application can also locate the edge of the battery cell 3 by visually identifying the welding strip between the battery cells 3, that is, it is not necessary to use the second light source under the workbench for the lighting process.

[0066] Figure 5 For Figure 2 The enlarged schematic diagram of B in, as Figure 5 shown, during the series welding process of the battery cell 3, the centers of the main grid line of the photovoltaic module, the welding strip between the battery cells 3, and the film strip 51 coincide. The position of the welding strip can be clearly observed through the film strip 51; and, since the overall size of the battery cell 3 is a fixed value, such as the length and width of the battery cell 3, the position of the main grid line, the width of the welding strip, etc., after identifying the edge of the welding strip by the visual detection method, the edge position information of the battery cell 3 can be calculated, and then compared with the edge position information of the film strip 51, and the overlapping distance between the film strip 51 and the battery cell 3 can be obtained. The recognition process includes the following steps:

[0067] Step S40, the photovoltaic backplane 5 of the photovoltaic module is placed face up on the workbench, the first light source above the photovoltaic module is turned on, and the image collector records the first edge position information 513 of the film strip 51 in the width direction;

[0068] Step S50, after the image collector identifies the position of the welding strip through the film strip 51, the second edge position information 34 of the battery cell 3 is obtained;

[0069] Step S60, the image collector analyzes the first edge position information 513 and the second edge position information 34, and obtains the difference between the two in the horizontal direction, where the difference is the overlapping distance between the film strip 51 and the battery cell 3.

[0070] Exemplarily, in step S50, the distance from the center line of the outermost main grid line of the photovoltaic module to the edge of the battery cell 3 is 10 mm, the width of the welding strip with the center coinciding with the center of the main grid line is 0.26 mm, and the distance from the edge of the welding strip to the edge of the battery cell 3 is 10 - 0.26 / 2 = 9.87 mm. Then, by the image collector identifying the position information of the welding strip, the edge of the battery cell 3 at 9.87 mm from the edge of the welding strip can be obtained.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A visual inspection method for photovoltaic modules, characterized in that, The photovoltaic module includes a plurality of solar cells and a photovoltaic backplane, and a plurality of film strips are provided on the photovoltaic backplane; the photovoltaic module further includes a plurality of groups of solar cell strings, the solar cell strings include a plurality of the solar cells connected in series, the film strip is disposed opposite to the sheet gap formed between the solar cells or the string gap formed between the solar cell strings, and the length of the film strip is less than the length of the sheet gap or the string gap; the visual inspection method includes the following steps: The first light source located above the photovoltaic module is turned on, and the image collector records the first coordinate and the second coordinate of the intersection of the end edges of the film strip. The second light source located below the photovoltaic module is turned on, and the image collector records the third coordinate and the fourth coordinate of the overlapping points of the edge of the solar cell, the end of the film strip, and the sheet gap or the string gap. The image collector analyzes the differences between the first coordinate and the third coordinate, and between the second coordinate and the fourth coordinate in the width direction of the sheet gap or the string gap, where the differences are the overlapping distances between the film strip and the solar cell. The width of the film strip is greater than the width of the sheet gap or the string gap, and at least a part of both ends of the film strip does not cover the sheet gap or the string gap along the length direction of the sheet gap or the string gap.

2. The visual inspection method according to claim 1, wherein The vertical distance between the first light source and the film strip is 50 mm to 500 mm.

3. The visual inspection method according to claim 1, wherein The luminous intensity of the first light source is 1000 Lm to 20000 Lm.

4. The visual inspection method according to claim 1, wherein The vertical distance between the second light source and the solar cell is 1 mm to 200 mm.

5. The visual inspection method according to claim 1, characterized in that The luminous intensity of the second light source is 1000 Lm to 20000 Lm.

6. The visual inspection method according to claim 1, wherein The length of the end of the sheet gap or the string gap not covered by the film strip is 0.5 mm to 200 mm.

7. The visual inspection method according to claim 1, wherein The vertical distance from the image collector to the solar cell is 100 mm to 600 mm.

8. The visual detection method according to claim 1, characterized in that, The width ratio of the film strip to the sheet gap or the string gap is (2.5 to 3.5):

1.

9. The visual inspection method according to claim 1, wherein Along the width direction of the sheet gap or the string gap, the overlapping distance between the film strip and the solar cell is 0.01 mm to 10 mm.

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