Device for sorting light and dark pieces of back contact solar cell
By using EL testing equipment and a high-resolution infrared camera in the solar cell sorting device, and combining the sorting system to sort the light and dark sheets with back contact solar cells, the problem of difficulty in effectively sorting the light and dark sheets in the prior art is solved, and a more efficient photovoltaic module packaging is achieved.
Patent Information
- Application Number
- CN202510368561.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-27
- Publication Date
- 2025-06-20
AI Technical Summary
The prior art is difficult to effectively sort the light and dark sheets of the back contact solar cells, resulting in low efficiency of the module during packaging and requires re-repair. The re-repair process is prone to destroy other battery cells, resulting in further reduction in efficiency.
A device that sorts back contacts the light and dark sheet of solar cell, including a robot, a CCD testing mechanism, a test device platform and an EL testing equipment, is used to inject low current through the EL testing equipment, and uses a high-resolution infrared camera to collect electroluminescent images, and combines the sorting system to sort the grayscale value of the cell.
It realizes the detection of the light and darkness degree and defects of multiple solar cells simultaneously, ensures the consistent sorting conditions, effectively solves the problem of light and darkness in the back contact battery packaging, and can screen out the fragments or scratches during transportation, improving the efficiency of photovoltaic modules.
Smart Images
Figure CN120169700A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of photovoltaic devices, and particularly to a device for sorting bright and dark wafers of back-contact solar cells. Background Art
[0002] A photovoltaic module is composed of a number of photovoltaic cells encapsulated in series and parallel. Based on the basic principles of circuits, we know that in the case of series-connected cells, if the current of one cell is smaller, the current of the entire series circuit will depend on the current of that cell. This is because the current is the same everywhere in a series circuit, that is, the current in the series circuit passes through each cell, and the magnitude of the current is determined by the cell with the smallest current. Before encapsulating into a module, IV testing and sorting of photovoltaic cells are preferably carried out first. The cells with closer current values are sorted together into one grade, and then further sorting is carried out on the voltage. The cells with closer voltage values are sorted together into one grade. After the above hierarchical sorting, the cells of the same grade are encapsulated into a module. The solar cells after IV testing and sorting are theoretically the most reasonable. However, there are still many problems before the cells are transferred to module encapsulation. For example, the cells are scratched after being stacked in packaging, and the cells decay during the standing process, etc. Such problems will cause the cells encapsulated in the same module to still have inconsistent problems, resulting in low module efficiency and the need for repair, etc. Currently, the main solution to such problems is to test EL after the cells are string-soldered, and then remove the cells with a large contrast between bright and dark for repair. This solution is very troublesome, and during the repair process, it is extremely easy to damage other cells, resulting in a further decrease in cell efficiency.
[0003] Of course, some solutions have proposed to further test and sort through PL (photoluminescence) technology before module encapsulation to screen out the cells with inconsistent PL grayscale. However, there is a major drawback to this screening solution. Whether it is single-piece screening or multi-piece screening, it can only screen out some relatively serious abnormal wafers, and it is not possible to compare the bright and dark wafers in the same module. Summary of the Invention
[0004] In view of the above problems, in order to overcome the defects of the prior art, based on the characteristic that all the electrodes of the back-contact solar cell are arranged on the back of the cell, the present invention provides a device for sorting bright and dark wafers of back-contact solar cells.
[0005] To solve the above technical problems, the technical solution adopted by the present invention is: a device for sorting bright and dark wafers of back-contact solar cells, comprising a manipulator, 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, suction holes, end busbars, 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 the segmented connecting wires and has gaps around. The height of the segmented connecting wires is slightly 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 segmented adsorption, and single-piece wafers are adsorbed through the suction holes arranged on the first buffer layer. A matching transparent lower pressing plate is arranged above the testing device platform. The substrate of the transparent lower pressing plate is a hard transparent layer, and a third buffer layer is arranged below the hard 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 lower pressing plate, and a sorting system that can distinguish bright and dark and defects through gray-scale recognition.
[0006] Further, the first buffer layer is a non-conductive high-elastic rubber plate.
[0007] Further, the second buffer layer is a non-conductive low-elastic rubber plate.
[0008] Further, the segmented connecting wires are flat copper wires or probe rows.
[0009] Further, the gap around the first buffer layer wrapping the segmented connecting wires is greater than 0.5 mm.
[0010] Further, the hard transparent layer is made of high-transparency glass or acrylic plate.
[0011] Further, the third buffer layer is made of laminated soft EVA or POE as the buffer layer, and its thickness is 0.3 - 1 mm.
[0012] Further, the regulated power supply of the EL testing device is connected to the end busbar through a test wire.
[0013] From the above description of the structure of the present invention, compared with the prior art, the present invention has the following advantages:
[0014] The present invention makes full use of the principle of electroluminescence (EL) of solar cells to simultaneously detect multiple solar cells. With the cooperation of a high-resolution camera and low-current (0.2A - 1A) injection, the brightness and defects of the above-mentioned battery cells can be simultaneously displayed. Then, a sorting system is used to sort the gray values of the corresponding battery cells, so as to achieve the purpose of screening out bright and dark pieces. It can ensure that the sorting conditions for all back-contact solar cells are consistent, effectively solving the problem of bright and dark pieces in the packaging of back-contact batteries in photovoltaic modules in the prior art. Moreover, after electroluminescence, not only can bright and dark be distinguished, but also some defective battery cells such as broken pieces and scratches during transportation can be screened out together, thereby further improving the efficiency of photovoltaic modules. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:
[0016] Figure 1 is a schematic diagram of the main structure of the device for sorting bright and dark back-contact solar cells of the present invention;
[0017] Figure 2 is a schematic diagram of the structure of the back-contact solar cell in Embodiment 1;
[0018] Figure 3 is a schematic diagram of the back structure of the back-contact solar cell after cutting in Embodiment 1;
[0019] Figure 4 is a schematic diagram of the structure of the device platform of the present invention covered with battery cells;
[0020] Figure 5 is Figure 1 a partially enlarged schematic diagram of the M area of;
[0021] Figure 6 is Figure 4 a partially enlarged schematic diagram of the N area of;
[0022] Figure 7 is Figure 4 a partially sectional schematic diagram of the A-A area of;
[0023] Figure 8 is a structural diagram of the layer relationship after the transparent lower pressing plate of the present invention is pressed down. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.
[0025] refer to Figures 1 - 7 A device for sorting light and dark sheets of back-contact solar cells, comprising a manipulator 10, a CCD testing mechanism 20, a testing device platform 30 and an EL testing device 50. The manipulator 10 cooperates with the CCD testing mechanism 20 to grab the back-contact solar cell onto the testing device platform 30 and adsorbs the cell onto the platform through the vacuum adsorption device of the testing device platform 30. The manipulator 10 can grab a single cell or a whole group of cells. The CCD testing mechanism 20 is composed of a CCD camera 21 and a CCD testing platform 22. The testing device platform 30 includes a first buffer layer 31, a segmented connecting wire 32, an air suction hole 33, an end bus bar 34, a second buffer layer 35, a support frame 36 and a vacuum adsorption device 37. The second buffer layer 35 is arranged above the support frame 36, the segmented connecting wire 32 is arranged above the second buffer layer 35, and the first buffer layer 31 wraps the segmented connecting wire 32 and leaves a gap around it, the gap is greater than 0.5mm, the segmented connecting wire 32 is arranged slightly lower than the first buffer layer 31, the two sides of the segmented connecting wire 32 are connected by the end bus bar 34, the vacuum adsorption device 37 is a segmented adsorption, and the single-chip battery sheet is adsorbed through the suction holes arranged on the first buffer layer 31, and a matching transparent lower pressing plate 40 is arranged above the test device platform 30, the substrate of the transparent lower pressing plate is a hard transparent layer 42, and a third buffer layer 41 is arranged below the hard transparent layer, the EL test equipment 50 includes a regulated power supply 51 connected to the input end of the segmented connecting wire, a high-resolution infrared camera 52 above the transparent lower pressing plate and a sorting system that can distinguish between light and dark and defects through grayscale recognition, and the regulated power supply 51 of the EL test equipment is connected to the end bus bar 34 through a test line 53.
[0026] The first buffer layer 31 is a non-conductive high-elastic rubber sheet with a smooth surface. The battery cells are placed on top and can be fixed by vacuum adsorption. The high-elastic rubber sheet will sink like a sponge after compression. The second buffer layer 35 is a non-conductive low-elastic rubber sheet, which plays a role in fixing the segmented connecting wires and buffering.
[0027] The segmented connecting wire 32 is a flat copper wire or a probe row, which is selected according to the battery electrodes.
[0028] The hard transparent layer 42 is made of highly transparent glass or acrylic plate.
[0029] The third buffer layer 41 uses laminated soft EVA and POE as the buffer layer, and its thickness is 0.3 - 1 mm.
[0030] When all the back-contact solar cells are arranged on the test device platform 30, the transparent lower pressing plate 40 presses down on the back-contact solar cells, contacts and squeezes through the third buffer layer 41 and the first buffer layer 31. When the first buffer layer 31 sinks to be flush with the segmented connecting wire 32, at this time, the segmented connecting wire 32 contacts the back electrode of the back-contact solar cell and forms a series circuit with the EL test device 50. A low current (0.2 A - 1 A) is injected through the regulated power supply 51 of the EL test device, and an EL image of the back-contact solar cell is collected by a high-resolution infrared camera 52 arranged above the transparent lower pressing plate 40. Further, the solar cells are sorted by the gray value, and the solar cells with brightness differences are screened out and removed. The selected solar cells flow into the next process for string welding and encapsulation into modules.
[0031] Example 1
[0032] As Figure 2 , Figure 3 shown, before the conventional back-contact solar cell 100 is cut, there is no grid line arrangement on the front side, and a positive electrode region 110, a negative electrode region 120, and a fine grid connection region 130 between the positive and negative electrodes are arranged on the back side; in order to reduce the current of the photovoltaic module, the battery is cut in half. After cutting, we will find that when the two solar cells face the same direction, the back battery partitions show opposite polarities. For example, the positive electrode region 110 of the solar cell 101 is the uppermost first one, and the second one is the negative electrode region 120, while the positive electrode region 110 of the solar cell 102 is the second one, and the uppermost first one is the negative electrode region 120. This wiring feature is beneficial for us to connect the solar cells in series on the back side through wires.
[0033] As Figure 1 shown, a device for sorting bright and dark back-contact solar cells uses the above-mentioned self-features of the solar cells, and sets up a special test device platform 30 to test and sort the solar cells. The manipulator 10 grabs the back-contact solar cell with the front side up placed on the test platform 22 of the CCD test mechanism 20, and accurately places the solar cell into the area arranged on the test device platform 30 according to the recognition system of the CCD camera 21. The test device platform 30 is provided with a first buffer layer 31, a segmented connecting wire 32, an air suction hole 33, and an end bus bar 34. The solar cell 101 and the solar cell 102 are placed alternately on the first buffer layer 310, and the placed area will completely cover the local air suction holes 330. The vacuum adsorption device 37 will form a good adsorption on a single solar cell to ensure that the electrode grid lines of the solar cell form a corresponding relationship with the segmented connecting wire 32.
[0034] like Figure 4 As shown, the solar cells 101 and 102 are staggered in the sorting area according to the electrode characteristics, and the transparent lower pressing plate 40 is pressed down. The third buffer layer 41 on the transparent lower pressing plate 40 presses the solar cells 101 and 102 down and makes the back electrodes form good contact with the segmented connecting wires 32. At this time, the solar cells to be sorted form a series loop, which is connected to the end bus bar 34 through the test line 53 of the voltage-stabilized power supply 51 of the EL testing equipment, and a current of 0.5A is injected. The EL image of the back contact cell is collected by a high-resolution infrared camera arranged above the transparent lower pressing plate, and the cell is further sorted according to the grayscale value between the cell.
[0035] In order to better explain the structure of the test device platform 30 and its arrangement relationship with the battery cells, as shown in FIG. Figure 5 As shown, Figure 1 The M region is enlarged, and the solar cell 101 and the solar cell 102 are perspectively processed. From left to right, three solar cells 101, 102, and 101 are arranged in sequence. The negative electrode 120 of the first cell 101 is connected to the positive electrode 110 of the second cell 102 through a segmented connecting wire 32, and the negative electrode 120 of the second cell 102 is connected to the positive electrode 110 of the third cell 101 through a segmented connecting wire 32, thereby repeatedly forming a series circuit. There is a group of suction holes 33 with independent adsorption force under the solar cells 101, 102, and 101 to ensure that each cell can be independently adsorbed on the first buffer layer 31.
[0036] like Figure 6 As shown, further Figure 4 The N region of the solar cell 101 is enlarged, and the positive electrode 110 and the negative electrode 120 of the solar cell 101 are in a corresponding relationship with the segmented connecting wire 32. In order to ensure good contact, the segmented connecting wire 32 completely covers the positive electrode 110 and the negative electrode 120. A gap is arranged around the first buffer layer 31 and the segmented connecting wire 32, and the gap width L is 1 mm.
[0037] like Figure 7 As shown, in order to further understand the structural layer relationship of the test device platform 30, Figure 5 The solar cells 101 and 102 are arranged on the first buffer layer 31, and are not in contact with the segmented connecting wires 32. The segmented connecting wires 32 are fixed on the second buffer layer 35. The second buffer layer 35 is fixed on the hard support frame 36, and the support frame 36 is provided with a vacuum adsorption device 37. When the transparent lower pressing plate is pressed down, Figure 8Schematic diagram. A hard transparent layer 42 and a third buffer layer 41 are provided on the transparent lower pressing plate 40. Driven by the hard transparent layer 420, the third buffer layer 41 is in positive contact with the solar cells 101 and 102. As the downward pressure increases, the first buffer layer 31 will sink, and then the backs of the solar cells 101 and 102 will form good contact with the segmented connecting wire 32. At this time, to ensure good contact of the electrodes, both the third buffer layer 41 and the second buffer layer 35 are in a compressed state. When injecting current, a high-resolution infrared camera 52 arranged above the transparent lower pressing plate 40 collects EL images of the solar cells 101 and 102, further sorts the cells through the gray values between the cells, eliminates the bright and dark pieces through the sorting system, and allows the sorted cells to flow into the component encapsulation lamination process.
[0038] Embodiment 2
[0039] Different from Embodiment 1, the segmented connecting wire 32 in Embodiment 2 is arranged in the form of a probe row, changing from the original line contact to point contact for current collection. The other settings are the same as those in Embodiment 1.
[0040] This embodiment is mainly aimed at the test sorting of back-contact solar cells without main grids and some solar cells with special electrode arrangements, and can solve the problem that the test areas of the electrodes of these cells are not concentrated.
[0041] The present invention makes full use of the principle of electroluminescence (EL) of solar cells to simultaneously detect multiple solar cells. With the cooperation of a high-resolution camera and low-current (0.2A - 1A) injection, the brightness and defects of the above-mentioned cells can be simultaneously displayed. Then, the sorting system is used to sort the gray values of the corresponding cells, so as to achieve the purpose of screening out bright and dark pieces, ensuring that the sorting conditions for all back-contact solar cells are consistent, effectively solving the problem of bright and dark pieces in the back-contact battery-packaged photovoltaic modules in the prior art. Moreover, after electroluminescence, not only can bright and dark be distinguished, but also some defective cells such as broken pieces and scratched pieces during transportation can be screened out, further improving the efficiency of the photovoltaic module.
[0042] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A device for sorting the bright and dark sheets of a back contact solar cell, characterized in that: It includes a manipulator, a CCD test mechanism, a test device platform and an EL test device. The CCD test mechanism is composed of a CCD camera and a CCD test platform. The test device platform includes a first buffer layer, a segmented connecting wire, an air suction hole, an end bus bar, a second buffer layer, a support frame and a vacuum adsorption device. The second buffer layer is arranged above the support frame, the segmented connecting wire is arranged above the second buffer layer, the first buffer layer wraps the segmented connecting wire and leaves a gap around it, the segmented connecting wire is arranged slightly lower than the first buffer layer, the two sides of the segmented connecting wire are connected by the end bus bar, the vacuum adsorption device is a segmented adsorption, and the single-chip battery sheet is adsorbed through the air suction hole arranged on the first buffer layer. A matching transparent lower pressing plate is arranged above the test device platform, the substrate of the transparent lower pressing plate is a hard transparent layer, and a third buffer layer is arranged below the hard transparent layer. The EL test device includes a voltage-stabilized power supply connected to the input end of the segmented connecting wire, a high-resolution infrared camera above the transparent lower pressing plate, and a sorting system that can distinguish light and dark and defects through grayscale recognition.
2. The device for sorting the bright and dark sheets of a back contact solar cell according to claim 1, characterized in that: The first buffer layer is a non-conductive high-elastic rubber sheet.
3. The device for sorting the bright and dark sheets of back contact solar cells according to claim 1, characterized in that: The second buffer layer is a non-conductive low-elastic rubber sheet.
4. The device for sorting the bright and dark sheets of a back contact solar cell according to claim 1, characterized in that: The segmented connecting wire is a flat copper wire or a probe row.
5. The device for sorting the bright and dark sheets of a back contact solar cell according to claim 1, characterized in that: The first buffer layer wraps around the segmented connecting wire with a gap greater than 0.5 mm.
6. The device for sorting the bright and dark sheets of a back contact solar cell according to claim 1, characterized in that: The hard transparent layer is made of highly transparent glass or acrylic plate.
7. The device for sorting the bright and dark sheets of a back contact solar cell according to claim 1, characterized in that: The third buffer layer is made of laminated soft EVA and POE, and its thickness is 0.3-1 mm.
8. The device for sorting the bright and dark sheets of a back contact solar cell according to claim 1, characterized in that: The voltage-stabilized power supply of the EL test equipment is connected to the end bus bar through a test line.