Device for sorting light and dark pieces of back contact solar cell

Abstract

The utility model discloses a device for sorting light and dark sheets of a back contact solar cell, which comprises a manipulator, a CCD (Charge Coupled Device) testing mechanism, a testing device platform and EL (Electroluminescence) testing equipment, the testing device platform comprises a first buffer layer, a sectional type connecting wire, an air suction hole, an end bus line, a second buffer layer, a supporting frame and a vacuum adsorption device, a matched transparent lower pressing plate is arranged above the testing device platform, a substrate of the transparent lower pressing plate is a hard transparent layer, a third buffer layer is arranged below the hard transparent layer, and the third buffer layer is arranged below the third buffer layer. The EL test equipment comprises a voltage-stabilized power supply connected with the input end of the sectional type connecting wire, a high-resolution infrared camera arranged above the transparent lower pressing plate and a sorting system capable of distinguishing light, shade and defects through gray scale identification. A solar cell electroluminescence principle is utilized, multiple solar cells are detected at the same time, the problem that light and dark pieces exist in a back contact cell packaging photovoltaic module is solved, and the efficiency of the photovoltaic module is improved.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic equipment, and in particular to a device for sorting back-contact solar cell light and dark sheets. Background Technology

[0002] A photovoltaic (PV) module is composed of several PV cells encapsulated in series and parallel. Based on basic circuit principles, we know that in a series circuit, if one cell has a lower current, the current of the entire series circuit will depend on the current of that single cell. This is because the current is the same everywhere in a series circuit; that is, the current in a series circuit flows through each cell, and the magnitude of the current is determined by the cell with the lowest current. Before being encapsulated into a module, PV cells undergo IV (Inductively Coupled) testing and sorting to group cells with similar current values ​​together. Further sorting is done by voltage, grouping cells with similar voltage values ​​together. After these multiple sorting stages, cells of the same grade are encapsulated into modules. Theoretically, PV cells sorted through IV testing are the most efficient. However, before being delivered to the module for encapsulation, many problems remain. For example, cells may be scratched during stacking and packaging, or their performance may degrade during resting. These issues can lead to inconsistencies among cells encapsulated in the same module, resulting in low module efficiency and the need for repairs. The current solution to this problem is to test the electroluminescence (EL) after the solar cells are wired together, and then remove the cells with large light-dark contrast for repair. This solution is very troublesome, and during the repair process, it is easy to damage other solar cells, causing the battery efficiency to decrease further.

[0003] Of course, some solutions propose further testing and sorting of cells before module encapsulation using PL (photoluminescence) technology to identify cells with inconsistent PL grayscale. However, this screening method has a major drawback: whether screening single cells or multiple cells together, it can only identify some severely abnormal cells and cannot compare the bright and dark cells within the same module. Utility Model Content

[0004] To address the aforementioned problems and overcome the shortcomings of existing technologies, this invention provides a device for sorting the bright and dark sheets of a back-contact solar cell, based on the characteristic that all electrodes of the back-contact solar cell are arranged on the back side of the cell.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: a device for sorting back-contact solar cell light and dark sheets, including a robotic arm, a CCD testing mechanism, a testing device platform, and an EL testing device. The CCD testing mechanism consists of a CCD camera and a CCD testing platform. The testing device platform includes a first buffer layer, segmented connecting wires, an air intake, an end busbar, a second buffer layer, a support frame, and a vacuum adsorption device. The second buffer layer is arranged above the support frame, and the segmented connecting wires are arranged above the second buffer layer. The first buffer layer wraps around the segmented connecting wires and leaves space around them. The segmented connecting wires are arranged at a height lower than the first buffer layer. The two sides of the segmented connecting wires are connected by end busbars. The vacuum adsorption device is a segmented adsorption device that adsorbs individual battery cells through suction holes arranged on the first buffer layer. A matching transparent pressure plate is provided above the test device platform. The substrate of the transparent pressure plate is a hard transparent layer. A third buffer layer is arranged below the hard transparent layer. The EL test equipment includes a regulated power supply connected to the input end of the segmented connecting wires, a high-resolution infrared camera above the transparent pressure plate, and a sorting system that can distinguish between light and dark areas and defects by grayscale identification.

[0006] Furthermore, the first buffer layer is a non-conductive, highly elastic rubber sheet.

[0007] Furthermore, the second buffer layer is a non-conductive, low-elasticity rubber sheet.

[0008] Furthermore, the segmented connecting wire is a flat copper wire or a probe array.

[0009] Furthermore, the first buffer layer surrounds the segmented connecting wires with a gap greater than 0.5 mm around its perimeter.

[0010] Furthermore, the rigid transparent layer is made of highly transparent glass or acrylic sheet.

[0011] Furthermore, the third buffer layer is made of laminated soft EVA and POE, with a thickness of 0.3~1mm.

[0012] Furthermore, the regulated power supply of the EL testing equipment is connected to the end busbar via test leads.

[0013] As can be seen from the above description of the structure of this utility model, compared with the prior art, this utility model has the following advantages:

[0014] This invention fully utilizes the electroluminescence (EL) principle of solar cells to simultaneously detect multiple solar cells. By using a high-resolution camera with low-current injection (0.2A ~ 1A), the brightness and defects of the cells can be simultaneously displayed. Then, a sorting system is used to sort the corresponding cells by their grayscale values, thereby achieving the purpose of filtering out cells with bright and dark areas. This ensures that the sorting conditions for all back-contact solar cells are consistent, effectively solving the problem of bright and dark areas in back-contact solar modules. Furthermore, after electroluminescence, not only can bright and dark areas be distinguished, but also some defective cells such as broken or scratched cells from the transportation process can be screened out, thereby further improving the efficiency of the photovoltaic module. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0016] Figure 1 This is a schematic diagram of the main structure of the device for sorting back-contact solar cell light and dark plates according to this utility model;

[0017] Figure 2 This is a schematic diagram of the back-contact solar cell structure in Example 1;

[0018] Figure 3 This is a schematic diagram of the back structure of the back contact solar cell after cutting in Example 1;

[0019] Figure 4 This is a schematic diagram of the structure of the test device platform of this utility model covered with battery cells;

[0020] Figure 5 for Figure 1 A magnified view of the M region;

[0021] Figure 6 for Figure 4 A magnified schematic diagram of the N region;

[0022] Figure 7 for Figure 4 A schematic diagram of a partial cross-section of region AA;

[0023] Figure 8 This is a structural diagram showing the layer relationship after the transparent pressure plate of this utility model is pressed down. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0025] refer to Figures 1-7 A device for sorting back-contact solar cells includes a robotic arm 10, a CCD testing mechanism 20, a testing platform 30, and an EL testing device 50. The robotic arm 10, in conjunction with the CCD testing mechanism 20, grips the back-contact solar cells onto the testing platform 30, and the platform 30 uses a built-in vacuum adsorption device to hold the cells on the platform. The robotic arm 10 can grip single cells or entire groups of cells. The CCD testing mechanism 20 consists of a CCD camera 21 and a CCD testing platform 22. The testing platform 30 includes a first buffer layer 31, segmented connecting wires 32, an air intake 33, an end busbar 34, a second buffer layer 35, a support frame 36, and a vacuum adsorption device 37. The second buffer layer 35 is positioned above the support frame 36, and the segmented connecting wires 32 are positioned above the second buffer layer 35. Layer 31 wraps around segmented connecting wires 32 with gaps around the perimeter greater than 0.5mm. The height of the segmented connecting wires 32 is lower than that of the first buffer layer 31. The two sides of the segmented connecting wires 32 are connected by end busbars 34. The vacuum adsorption device 37 is a segmented adsorption device that adsorbs single battery cells through suction holes arranged on the first buffer layer 31. A matching transparent pressure plate 40 is provided above the test device platform 30. The substrate of the transparent pressure plate is a rigid transparent layer 42. A third buffer layer 41 is arranged below the rigid transparent layer. The EL test equipment 50 includes a regulated power supply 51 connected to the input end of the segmented connecting wires, a high-resolution infrared camera 52 above the transparent pressure plate, and a sorting system that can distinguish between light and dark and defects by grayscale identification. The regulated power supply 51 of the EL test equipment is connected to the end busbars 34 through test lines 53.

[0026] The first buffer layer 31 is a non-conductive high-elastic rubber sheet with a smooth surface. The battery cell is placed on top and can be fixed by vacuum adsorption. After compression, the high-elastic rubber sheet will sink like a sponge. The second buffer layer 35 is a non-conductive low-elastic rubber sheet, which serves to fix the segmented connecting wires and provide buffering.

[0027] The segmented connecting wire 32 is a flat copper wire or probe array, selected according to the battery electrodes.

[0028] The rigid transparent layer 42 is made of highly transparent glass or acrylic sheet.

[0029] The third buffer layer 41 is made of laminated soft EVA and POE, with a thickness of 0.3~1mm.

[0030] When all the back-contact solar cells are arranged on the test platform 30, the transparent pressure plate 40 presses down on the back-contact solar cells, making contact and squeezing them through the third buffer layer 41 and the first buffer layer 31. When the first buffer layer 31 is flush with the segmented connecting wire 32, the segmented connecting wire 32 contacts the back electrode of the back-contact solar cell and forms a series circuit with the EL test equipment 50. A low current (0.2A ~ 1A) is injected through the regulated power supply 51 of the EL test equipment, and the back-contact solar cells are captured by the high-resolution infrared camera 52 arranged above the transparent pressure plate 40. The solar cells are further sorted by grayscale value, and those with differences in brightness are screened out and rejected. The selected solar cells flow into the next process for string bonding and encapsulation into modules.

[0031] Example 1

[0032] like Figure 2 , Figure 3 As shown, a conventional back-contact solar cell 100 has no grid lines on the front before cutting, and has a positive electrode area 110, a negative electrode area 120, and a fine grid connection area 130 between the positive and negative electrodes on the back. In order to reduce the current of the photovoltaic module, the cell is cut in half. After cutting, we will find that if the two cells are facing the same direction, the back cell partitions show opposite polarities. For example, the positive electrode area 110 of solar cell 101 is the first one at the top, and the second one is the negative electrode area 120, while the positive electrode area 110 of solar cell 102 is the second one, and the first one at the top is the negative electrode area 120. This wiring feature is beneficial for connecting the cells in series on the back by wires.

[0033] like Figure 1 As shown, an apparatus for sorting back-contact solar cells utilizes the inherent characteristics of the solar cells and sets up a dedicated testing platform 30 to test and sort the cells. A robotic arm 10 grasps the front-facing back-contact solar cells placed on the testing platform 22 of the CCD testing mechanism 20, and accurately places the cells into the designated area on the testing platform 30 according to the recognition system of the CCD camera 21. The testing platform 30 is provided with a first buffer layer 31, segmented connecting wires 32, air intake holes 33, and end busbars 34. Solar cells 101 and 102 are placed alternately on the first buffer layer 310, and the placement area completely covers the air intake holes 330 in some areas. The vacuum adsorption device 37 forms a good adsorption for individual cells, ensuring that the electrode grid lines of the solar cells correspond to the segmented connecting wires 32.

[0034] like Figure 4 As shown, solar cells 101 and 102 are arranged alternately in the sorting area according to their electrode characteristics. A transparent pressure plate 40 is pressed down, and the third buffer layer 41 on the transparent pressure plate 40 presses down the solar cells 101 and 102, making good contact between their back electrodes and the segmented connecting wires 32. At this time, all the solar cells to be sorted form a series circuit. The test line 53 of the regulated power supply 51 of the EL test equipment is connected to the end bus line 34, and a current of 0.5A is injected. The high-resolution infrared camera arranged above the transparent pressure plate acquires EL images of the back contact cells, and the cells are further sorted by the gray values ​​between them.

[0035] To better illustrate the structure of the test device platform 30 and its relationship with the solar cells, such as Figure 5 As shown, Figure 1 The M region is magnified, and solar cells 101 and 102 are rendered with a transparent view. Three solar cells 101, 102, and 101 are arranged sequentially from left to right. The negative electrode 120 of the first cell 101 is connected to the positive electrode 110 of the second cell 102 via a segmented connecting wire 32. The negative electrode 120 of the second cell 102 is then connected to the positive electrode 110 of the third cell 101 via the same segmented connecting wire 32, thus forming a series circuit. Each solar cell 101, 102, and 101 has a set of suction holes 33 with individual adsorption force below it, ensuring that each cell can be individually adsorbed onto the first buffer layer 31.

[0036] like Figure 6 As shown, further Figure 4 Enlarging the N region, the positive electrode 110 and negative electrode 120 of the solar cell 101 correspond to the segmented connecting wire 32. To ensure good contact, the segmented connecting wire 32 completely covers the positive electrode 110 and negative electrode 120 regions. The first buffer layer 31 and the segmented connecting wire 32 are surrounded by gaps with a gap width L of 1 mm.

[0037] like Figure 7 As shown, in order to further understand the structural layer relationships of the test device platform 30, the following will be discussed: Figure 5 The AA region is cut. Solar cells 101 and 102 are arranged on the first buffer layer 31, and are not in contact with the segmented connecting wire 32 at this time. The segmented connecting wire 32 is fixed above the second buffer layer 35, which is fixed above the rigid support frame 36, and the support frame 36 is equipped with a vacuum adsorption device 37. When the transparent pressure plate is pressed down, [the following can be obtained] Figure 8A schematic diagram is shown. A rigid transparent layer 42 and a third buffer layer 41 are disposed on the transparent pressure plate 40. Driven by the rigid transparent layer 420, the third buffer layer 41 makes contact with the front surfaces of solar cells 101 and 102. As the downward pressure increases, the first buffer layer 31 sinks, allowing the back surfaces of solar cells 101 and 102 to form good contact with the segmented connecting wires 32. At this time, to ensure good electrode contact, both the third buffer layer 41 and the second buffer layer 35 are in a compressed state. Under injected current, a high-resolution infrared camera 52 positioned above the transparent pressure plate 40 acquires EL images of solar cells 101 and 102. The cells are further sorted based on their grayscale values. A sorting system removes bright and dark cells, and the sorted cells flow into the module encapsulation and lamination process.

[0038] Example 2

[0039] Unlike Embodiment 1, the segmented connecting wires 32 in Embodiment 2 are arranged using a probe array, changing the original line contact to point contact for current merging. All other settings are the same as in Embodiment 1.

[0040] This embodiment is mainly for testing and sorting solar cells without a main grid back contact and some irregularly arranged electrodes, and can solve the problem of the non-concentrated electrode testing area of ​​the battery.

[0041] This invention fully utilizes the electroluminescence (EL) principle of solar cells to simultaneously detect multiple solar cells. By using a high-resolution camera with low-current injection (0.2A ~ 1A), the brightness and defects of the cells can be simultaneously displayed. Then, a sorting system is used to sort the corresponding cells by their grayscale values, thereby achieving the purpose of filtering out cells with bright and dark areas. This ensures that the sorting conditions for all back-contact solar cells are consistent, effectively solving the problem of bright and dark areas in back-contact solar modules. Furthermore, after electroluminescence, not only can bright and dark areas be distinguished, but also some defective cells such as broken or scratched cells from the transportation process can be screened out, thereby further improving the efficiency of the photovoltaic module.

[0042] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A device for sorting back-contact solar cell light and dark plates, characterized in that: The system includes a robotic arm, a CCD testing mechanism, a testing platform, and an EL testing device. The CCD testing mechanism consists of a CCD camera and a CCD testing platform. The testing platform includes a first buffer layer, segmented connecting wires, suction holes, end busbars, a second buffer layer, a support frame, and a vacuum adsorption device. The second buffer layer is positioned above the support frame, and the segmented connecting wires are positioned above the second buffer layer. The first buffer layer wraps around the segmented connecting wires with gaps around them. The height of the segmented connecting wires is lower than that of the first buffer layer. The two sides of the segmented connecting wires are connected by end busbars. The vacuum adsorption device is a segmented adsorption device that adsorbs individual solar cells through suction holes arranged on the first buffer layer. A matching transparent pressure plate is provided above the testing platform. The substrate of the transparent pressure plate is a rigid transparent layer, and a third buffer layer is arranged below the rigid transparent layer. The EL testing device includes a regulated power supply connected to the input end of the segmented connecting wires, a high-resolution infrared camera above the transparent pressure plate, and a sorting system that can distinguish between light and dark areas and defects through grayscale identification.

2. The apparatus for sorting back-contact solar cell light and dark plates according to claim 1, characterized in that: The first buffer layer is a non-conductive, highly elastic rubber sheet.

3. The apparatus for sorting back-contact solar cell light and dark plates according to claim 1, characterized in that: The second buffer layer is a non-conductive, low-elasticity rubber sheet.

4. The apparatus for sorting back-contact solar cell light and dark plates according to claim 1, characterized in that: The segmented connecting wires are flat copper wires or probe arrays.

5. The apparatus for sorting back-contact solar cell light and dark plates according to claim 1, characterized in that: The first buffer layer surrounds the segmented connecting wires with a gap greater than 0.5 mm around its perimeter.

6. The apparatus for sorting back-contact solar cell light and dark plates according to claim 1, characterized in that: The rigid transparent layer is made of highly transparent glass or acrylic sheet.

7. The apparatus for sorting back-contact solar cell light and dark plates according to claim 1, characterized in that: The third buffer layer is made of laminated soft EVA and POE, with a thickness of 0.3~1mm.

8. The apparatus for sorting back-contact solar cell light and dark plates according to claim 1, characterized in that: The regulated power supply of the EL testing equipment is connected to the end busbar via test leads.

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