Method for optimizing number of probe rows in EL test and EL test machine

Abstract

The invention provides a method for optimizing the number of probe rows in an EL test and an EL test machine. The method for optimizing the number of the probe rows in the EL test can effectively prevent abnormal battery pieces from flowing into an assembly end, and comprises the following steps: gradually reducing the number of the probe rows, and carrying out the multi-dimensional EL test on the battery pieces by adopting a probe assembly after the probe rows are reduced every time, if the battery piece test result of each dimension in the multi-dimensional battery piece EL test accords with the corresponding preset value, continuing to reduce the number of the current probe rows of the probe assembly until the battery piece test result of at least one dimension in the multi-dimensional battery piece EL test does not accord with the corresponding preset value, and recording the number of the current probe rows as N, the number of the probe rows in the last multi-dimensional cell EL test is recorded as N ', the optimized numerical value Y of the number of the probe rows is determined in a numerical value interval with N and N' as endpoints, and the multi-dimensional cell EL test comprises manual static EL test, automatic dynamic EL test, GRamp, R test and comparison EL test before and after the number of the probe rows is reduced.

Description

Technical Field

[0001] This application relates to the field of solar cell testing, and in particular to a method for selecting the number of probe arrays and an EL testing machine for solar cell EL testing. Background Technology

[0002] In the field of solar cell manufacturing, abnormal cell appearance and EL defects are unavoidable problems in the cell manufacturing industry. In addition to continuous improvement of the process within the workshop, identification and control through EL testing equipment is also an indispensable part. As the last link in the entire workshop, preventing abnormal products from leaving and controlling them is the top priority of the packaging workshop's responsibilities within the company.

[0003] Currently, the main problems encountered by solar cells on EL testing machines include: black spots, irregular black patches, corner black spots, poor printing, broken EL grids, cloudy black spots, and graphite boat marks, etc. During EL testing, when the probe array presses down on the solar cell, it makes contact with the main grid position. Due to the influence of probe array obstruction in the EL testing device, many types of solar cells exhibiting abnormal blackening during EL testing cannot be effectively identified and controlled. Examples of abnormal blackening include: blackening at the main grid position during EL testing, slight black edges on cells parallel to the main grid edge, and slight grid breaks. This can easily lead to defective products entering the module assembly, causing customer complaints, affecting the quality of photovoltaic modules, and increasing compensation losses. Summary of the Invention

[0004] The first aspect of this application provides a method for optimizing the number of probe rows in EL testing. Based on the conventionally set number of probe rows M in the original probe assembly of the EL testing machine, the number of probe rows is gradually reduced. Multi-dimensional EL testing of solar cells is performed using the probe assembly after each reduction in probe rows. If the test results for each dimension of the solar cell meet the corresponding preset values ​​in the multi-dimensional EL testing, the current number of probe rows in the probe assembly is further reduced.

[0005] The test continues until at least one dimension of the cell EL test fails to meet the corresponding preset value. Then, the current number of probe arrays is recorded as N, and the number of probe arrays in the previous multi-dimensional cell EL test is recorded as N', where N and N' are both natural numbers.

[0006] If the difference between N and N' is 1, then N' is the optimized value Y for the number of probe rows; if the difference between N and N' is greater than 1, then the optimized value Y for the number of probe rows is determined in the numerical range with N and N' as endpoints. The determination condition is: in the multi-dimensional EL test of the battery cell using Y probe rows, the test results of each dimension of the battery cell meet the corresponding preset value; in the multi-dimensional EL test of the battery cell using Y-1 probe rows, the test results of at least one dimension of the battery cell do not meet the corresponding preset value.

[0007] Multi-dimensional EL testing of solar cells includes: manual static EL testing of solar cells on an EL testing machine, automatic dynamic EL testing of solar cells on an EL testing machine, GR&R testing of EL testing machines after the number of probe rows is reduced, and comparative EL testing before and after the reduction of the number of probe rows.

[0008] In some optional embodiments of the first aspect of this application, manual static EL testing of the solar cells on an EL testing machine includes:

[0009] The first cell that passed the EL test on the production line is placed on the EL testing machine under the probe assembly. The probe assembly is manually pressed down onto the first cell and then left to stand still. All the probe rows in the probe assembly are electrically connected to the multiple main grids of the first cell. In the standing state, 'a' EL tests are performed on the first cell continuously to obtain the cell conversion efficiency for each EL test.

[0010] Calculate the first overall battery conversion efficiency range in a EL test. When the first overall battery conversion efficiency range is less than the preset value of the first battery conversion efficiency range, it is determined that the cell test result in this dimension meets the corresponding preset value.

[0011] In some optional embodiments of the first aspect of this application, the preset value for the first battery conversion efficiency range is 0.02%.

[0012] In some optional embodiments of the first aspect of this application, the value of a ranges from 10 to 15.

[0013] In some optional embodiments of the first aspect of this application, the automatic dynamic EL testing of the solar cells on an EL testing machine includes:

[0014] Select the second cell that has passed the EL test on the production line, set the EL test machine to automatic detection mode, repeat the automatic EL test b times and calculate the range of conversion efficiency of the second overall cell in the b automatic EL test. When the range of conversion efficiency of the second overall cell is less than the preset value of the range of conversion efficiency of the second cell, it is determined that the cell test result in this dimension meets the corresponding preset value.

[0015] An automated EL test includes: the second solar cell is automatically fed into the EL testing machine, the probe assembly is automatically controlled to press down on the second solar cell, and all the probe rows in the probe assembly are electrically connected to the multiple main grids of the second solar cell one by one to perform EL testing on the second solar cell.

[0016] In some optional embodiments of the first aspect of this application, the preset value for the second battery conversion efficiency range is 0.04%.

[0017] In some optional embodiments of the first aspect of this application, the value of b ranges from 10 to 15.

[0018] In some optional embodiments of the first aspect of this application, the GR&R test for an EL testing machine with a reduced number of probe arrays includes:

[0019] Prepare c mainstream performance test chips;

[0020] d operators will be randomly selected;

[0021] Each operator performs e rounds of automatic continuous EL testing on c mainstream efficiency test chips. The total amount of EL test efficiency data I obtained is the product of d, c, and e.

[0022] Based on the EL test efficiency data volume I, calculate the EL testing machine variation (EV) reflecting repeatability and the evaluator variation (AV) reflecting reproducibility, according to R&R. 2 =EV 2 +AV 2 The calculated GR&R value is used to determine when the GR&R value is less than the preset tolerance value of the cell test data specification.

[0023] If the test results of the battery cells in this dimension are found to meet the corresponding preset values, then it is determined that the test results meet the preset values.

[0024] In some optional embodiments of the first aspect of this application, the preset value of the tolerance for the battery cell test data specification is 10%. In some optional embodiments of the first aspect of this application, the value of c ranges from 10 to 20, the value of d ranges from 3 to 5, and the value of e ranges from 3 to 10.

[0025] In some optional embodiments of the first aspect of this application, in each automatic continuous EL test, the EL testing machine is set to an automatic detection state, and an operator feeds c efficiency mainstream test pieces in sequence and automatically transfers them into the EL testing machine. The probe assembly is automatically controlled to press down on the efficiency mainstream test pieces, and all probe rows in the probe assembly are electrically connected to the multiple main grids of the efficiency mainstream test pieces one-to-one, so as to perform EL testing on the efficiency mainstream test pieces.

[0026] In some optional embodiments of the first aspect of this application, the comparative EL test before and after the reduction of the number of probe rows includes:

[0027] The EL testing machine with the original M probe rows is calibrated using a standard sheet to ensure that the calibration value is within the range required by the standard sheet. Then, f third cells that have passed the EL test on the production line are selected and EL tested on the EL testing machine with the original M probe rows respectively. The first average value X1 of the cell conversion efficiency of the f third cells is calculated.

[0028] The standard sheet is used to calibrate the EL tester with M' probe rows. f third cells that have passed the EL test on the production line are taken and EL tested on the EL tester with M' probe rows respectively. The second average value X2 of the cell conversion efficiency of the f third cells is calculated. M' is the number of probe rows in the current probe assembly after each reduction of probe rows.

[0029] When the absolute value of the difference between the first average value X1 and the second average value X2 is less than a preset value, the test result of the battery cell in that dimension is determined to meet the corresponding preset value.

[0030] In some optional embodiments of the first aspect of this application, the preset value of the absolute value is 0.05%.

[0031] In some optional embodiments of the first aspect of this application, gradually reducing the number of probe arrays includes:

[0032] Reduce the number of probe rows closest to the edge of the solar cell;

[0033] Furthermore, when the total number of reduced probe rows is greater than 1, at least two of the reduced probe rows are spaced apart on the original set of M probe rows.

[0034] In some optional embodiments of the first aspect of this application,

[0035] When the total number of reduced probe rows is greater than 1, all reduced probe rows are evenly spaced apart from the original set of M probe rows.

[0036] The second aspect of this application provides an EL testing machine, which has a probe assembly including multiple probe rows. During the EL testing process, the probe rows are positioned above the solar cell, and all probe rows in the probe assembly are electrically connected to multiple main grids on the solar cell in a one-to-one correspondence. The ratio of the number of probe rows in the probe assembly to the number of main grid lines on the solar cell tested by the EL testing machine is 0.3 to 0.6.

[0037] In some optional embodiments of the second aspect of this application, the probe rows in the probe assembly are evenly spaced in the multiple probe row arrangement directions, and there is at least one main grid line between every two adjacent probe rows.

[0038] In some optional embodiments of the second aspect of this application, in the multiple probe array arrangement direction, the outermost probe array is spaced apart from the corresponding edge of the battery cell by at least one main grid line.

[0039] Beneficial effects:

[0040] The method for optimizing the number of probe rows in EL testing provided in the first aspect of this application reduces and optimizes the number of probe rows in the probe assembly of the existing EL testing machine. While ensuring the quality of EL testing, it can effectively avoid the problem of probe row obstruction caused by the original large number of probe rows, which leads to the failure to effectively identify blackened and broken grids on the cells during EL testing. It effectively controls blackened and abnormal cells during the EL testing of cells, preventing actual blackened and abnormal cells from flowing into the subsequent photovoltaic module end, ensuring the quality of downstream photovoltaic module products and reducing customer complaint rate.

[0041] The EL testing machine provided in the second aspect of this application optimizes the number of probe rows in the EL testing using the method for optimizing the number of probe rows in the first aspect of this application. While ensuring high-quality and effective EL testing, it effectively controls solar cells that fail to be effectively identified due to blackening abnormalities during EL testing caused by probe row obstruction. It also reduces the number of probe row replacements required for solar cells, saves production costs, and improves the quality control of finished solar cells. This is conducive to further improving the quality of photovoltaic modules and enhancing customer satisfaction. Attached Figure Description

[0042] Figure 1 This is a schematic diagram showing the blackening of the main busbar after the solar cells that underwent EL testing before the number of probe arrays was optimized are welded into modules.

[0043] Figure 2 This is a schematic diagram of the GR&R data entry table format;

[0044] Figure 3 This is a schematic diagram of the GR&R analysis report form format;

[0045] Figure 4 This is a comparison diagram of an embodiment of the second aspect of this application before and after the optimization and reduction of the main gate.

[0046] Explanation of reference numerals in the attached figures:

[0047] 1-Probe array; 2-Solar cell; 21-Main busbar. Detailed Implementation

[0048] The following will be combined with the appendix Figures 1 to 4 The technical solution of this application is described in detail.

[0049] The first aspect of this application provides a method for optimizing the number of probe rows in EL testing. This method uses the conventionally set number of probe rows M in the original probe assembly of the EL testing machine as a base, gradually reducing the number of probe rows. Multi-dimensional EL testing of solar cells is performed using the probe assembly after each reduction in probe rows. If the test results for each dimension of the solar cell meet the corresponding preset values ​​in the multi-dimensional EL testing, the current number of probe rows in the probe assembly is further reduced.

[0050] The test continues until at least one dimension of the cell EL test fails to meet the corresponding preset value. Then, the current number of probe arrays is recorded as N, and the number of probe arrays in the previous multi-dimensional cell EL test is recorded as N', where N and N' are both natural numbers.

[0051] If the difference between N and N' is 1, then N' is the optimized value Y for the number of probe rows; if the difference between N and N' is greater than 1, then the optimized value Y for the number of probe rows is determined in the numerical range with N and N' as endpoints. The determination condition is: the test results of each dimension of the battery cell in the multi-dimensional battery cell EL test using Y probe rows meet the corresponding preset value, and the test results of at least one dimension of the battery cell in the multi-dimensional battery cell EL test using Y-1 probe rows do not meet the corresponding preset value.

[0052] Multi-dimensional EL testing of solar cells includes: manual static EL testing of solar cells on an EL testing machine, automatic dynamic EL testing of solar cells on an EL testing machine, GR&R testing of EL testing machines after the number of probe rows is reduced, and comparative EL testing before and after the reduction of the number of probe rows.

[0053] The method for optimizing the number of probe rows in EL testing provided in the first aspect of this application reduces and optimizes the number of probe rows in existing EL testing equipment. While ensuring EL testing quality, it effectively avoids the problem of probe row obstruction caused by a large number of probe rows, which could lead to issues such as blackened main grids and minor grid breaks on the solar cells not being effectively identified during EL testing. This effectively controls blackened abnormal cells during the EL testing process, preventing them from flowing into subsequent photovoltaic module production, thus ensuring the quality of downstream photovoltaic module products and reducing customer complaints. Figure 1 As shown, due to Figure 1 Left small Figure 1 Before optimization of the probe array number in the EL testing process, the number of probe arrays was large, and the number of probe arrays basically corresponded one-to-one with the number of main gate lines. This obscured the main gate, making it impossible to identify the blackening problem of the main gate. Figure 1 right small Figure 1As shown in b, the defective solar cells flowed into the module, causing blackening at the main busbar after the solar cells were welded to form the photovoltaic module. This resulted in a significant drop in the quality of the photovoltaic module and could easily lead to customer complaints.

[0054] In some embodiments of the first aspect of this application, the number of probe rows reduced each time can be consistent or variable. For example, initially, to improve optimization efficiency, the value n for reducing the number of probe rows can be set relatively large, such as 2 or 3, and later n can be adjusted to 1. Alternatively, n can be set to 1 from the beginning, and one probe row can be subtracted each time the number of probe rows is reduced.

[0055] In one example, the method for optimizing the number of probe rows in EL testing: The probe assembly of the EL testing machine originally has 11 probe rows, including:

[0056] S10: Reset the number of probe rows in the EL tester, reduce the current number of probe rows by 1, and the remaining number of probe rows in the probe assembly is M', that is, M' is the number of probe rows in the current probe assembly after each reduction of probe rows;

[0057] S20: Perform multi-dimensional EL testing on the solar cell using a probe assembly with M' probe rows. If the test results of each dimension of the solar cell meet the corresponding preset values ​​in the multi-dimensional EL testing, then return to step S10.

[0058] After six complete optimization cycles consisting of step S10 (with n set to 1 each time step S10 is executed) and step S20, in the seventh optimization cycle, the number of remaining probe rows in the probe assembly in step S10 is M' = 4. However, after performing multi-dimensional cell EL testing in step S20, the cell test results of at least one dimension in the multi-dimensional cell EL test do not meet the corresponding preset value. Therefore, the current number of probe rows of 4 is recorded as N, and the number of probe rows in the previous multi-dimensional cell EL test is recorded as N', N' = 5.

[0059] Since when the number of probe rows is reduced from 5 to 4, and a probe assembly with 4 probe rows is used to perform multi-dimensional cell EL testing, the first occurrence is that the cell test result of at least one dimension in the multi-dimensional cell EL test does not meet the corresponding preset value. Therefore, the optimized value Y for the number of probe rows is determined to be 5 in the interval [4, 5].

[0060] In another specific example, the method for optimizing the number of probe rows in EL testing: The probe assembly of the EL testing machine originally has 11 probe rows, including:

[0061] First optimization loop:

[0062] S10: Reset the number of probe rows in the EL tester, reducing the current number of probe rows by 4, and the remaining number of probe rows in the probe assembly is M' = 7;

[0063] S20: Perform multi-dimensional EL testing on the solar cell using a probe assembly with M' = 7 probe rows. If the test results for each dimension of the solar cell meet the corresponding preset values, then return to step S10 (enter the second optimization loop).

[0064] Second optimization loop:

[0065] S10: Reset the number of probe rows in the EL tester, reducing the current number of probe rows by 2, and the remaining number of probe rows in the probe assembly is M' = 5;

[0066] S20: Perform multi-dimensional EL testing on the solar cell using a probe assembly with M' probe rows. If the test results of each dimension of the solar cell meet the corresponding preset values, then return to step S10 (enter the third optimization loop).

[0067] The third optimization loop:

[0068] S10: Reset the number of probe rows in the EL tester, reducing the current number of probe rows by 2, and the remaining number of probe rows in the probe assembly is M' = 3;

[0069] S20: Multi-dimensional solar cell EL testing is performed using a probe assembly with M' probe rows. In the multi-dimensional solar cell EL test, the test results of each dimension of the solar cell do not all meet the corresponding preset values. The current number of probe rows is recorded as N, N=3. The number of probe rows in the previous multi-dimensional solar cell EL test is 5 and recorded as N'. The optimized value Y of the number of probe rows is determined in the numerical interval [3, 5] with N and N' as endpoints.

[0070] Further optimization:

[0071] S10': Reset the number of probe rows in the EL tester. Select 4 from the value range [3, 5] with N and N' as endpoints to set the current number of probe rows. The number of remaining probe rows in the probe assembly is 4.

[0072] S20': Multi-dimensional EL testing of solar cells is performed using a probe assembly with four probe rows. During the multi-dimensional EL testing, the test results for each dimension of the solar cell do not all conform to the corresponding preset values. That is, when the number of probe rows decreases from N'=5 to 4, and the multi-dimensional EL testing is performed using the probe assembly with four probe rows, the first instance occurs where the test result for at least one dimension of the solar cell does not conform to the corresponding preset value. That is, Y=5.

[0073] In some optional embodiments of the first aspect of this application, manual static EL testing of the solar cells on an EL testing machine includes:

[0074] The first cell that passed the EL test on the production line is placed on the EL testing machine under the probe assembly. The probe assembly is manually pressed down onto the first cell and then left to stand still. All the probe rows in the probe assembly are electrically connected to the multiple main grids of the first cell. In the standing state, 'a' EL tests are performed on the first cell continuously to obtain the cell conversion efficiency for each EL test.

[0075] Calculate the first overall battery conversion efficiency range in a EL test. When the first overall battery conversion efficiency range is less than the preset value of the first battery conversion efficiency range, it is determined that the cell test result in this dimension meets the corresponding preset value.

[0076] In some optional embodiments of the first aspect of this application, the preset value for the first battery conversion efficiency range is 0.02%.

[0077] In some optional embodiments of the first aspect of this application, the value of a ranges from 10 to 15.

[0078] In some optional embodiments of the first aspect of this application, a is 10.

[0079] In these embodiments, the first cell that passes the EL test on the production line is a cell that has passed all tests and is packaged.

[0080] In some embodiments, the probe array number optimization method in EL testing involves an EL testing machine with an original configuration of 11 probe arrays in the probe assembly and 11 main grid lines on the solar cell corresponding to the probe arrays.

[0081] In other embodiments, the number of main grid lines on the solar cell is not exactly the same as the number of probe rows, but only similar.

[0082] In some optional embodiments of the first aspect of this application, the automatic dynamic EL testing of the solar cells on an EL testing machine includes:

[0083] Select the second cell that has passed the EL test on the production line, set the EL test machine to automatic detection mode, repeat the automatic EL test b times and calculate the range of conversion efficiency of the second overall cell in the b automatic EL test. When the range of conversion efficiency of the second overall cell is less than the preset value of the range of conversion efficiency of the second cell, it is determined that the cell test result in this dimension meets the corresponding preset value.

[0084] An automated EL test includes: the second solar cell is automatically fed into the EL testing machine, the probe assembly is automatically controlled to press down on the second solar cell, and all the probe rows in the probe assembly are electrically connected to the multiple main grids of the second solar cell one by one to perform EL testing on the second solar cell.

[0085] In these embodiments, the battery cell loading process can be carried out by an operator placing the battery cells on the loading box. Then, the battery cells in the loading box are automatically transferred to the EL testing machine for EL testing via an assembly line.

[0086] In some optional embodiments of the first aspect of this application, the preset value for the second battery conversion efficiency range is 0.04%. This dimension of battery cell testing can reflect the stability of the electrical data tested by the EL testing machine.

[0087] In some optional embodiments of the first aspect of this application, the value of b ranges from 10 to 15.

[0088] In some alternative embodiments of the first aspect of this application, b is 10.

[0089] In some optional embodiments of the first aspect of this application, the GR&R test for an EL testing machine with a reduced number of probe arrays includes:

[0090] Prepare c mainstream performance test chips, where the value of c ranges from 10 to 20, such as c = 10;

[0091] Randomly select d operators, where the value of d ranges from 3 to 5, such as d = 3;

[0092] Each operator performs e rounds (e is 3 to 10, e=3) of automatic continuous EL testing on c mainstream efficiency test chips. The total amount of EL test efficiency data I obtained is the product of d, c and e, that is, the amount of EL test efficiency data I is 90.

[0093] like Figure 2 and Figure 3 As shown, copy the EL test efficiency data volume I to the GR&R data entry table, and calculate the EL testing machine variation EV, which reflects repeatability, and the evaluator variation AV, which reflects reproducibility, according to R&R. 2 =EV 2 +AV 2 The GR&R value is calculated and written into the GR&R analysis report table. When the GR&R value is less than 10% of the tolerance of the cell test data specification, the cell test result under this dimension is determined to meet the corresponding preset value.

[0094] The EL test efficiency data volume I is 90.

[0095] In some cases, the term "mainstream efficiency test cell" refers to a cell in a batch that has a relatively high proportion of cells with a certain efficiency, exceeding a predetermined percentage. This cell is considered a mainstream efficiency test cell. Specifically, if the proportion of cells with an efficiency of X% ± 0.2% in the same production batch is 30% to 70%, then these cells with an efficiency of X% ± 0.2% are considered mainstream efficiency test cells.

[0096] GR&R is an abbreviation for Gauge Repeatability and Reproducibility, meaning the repeatability and reproducibility of a measurement system. Under the same zeroing conditions and with data acquired within a short time, GR&R is used to evaluate the accuracy and reliability of a measurement system and process. Specifically, repeatability refers to the consistency of results obtained by the same operator measuring the same object multiple times under identical conditions; reproducibility refers to the consistency of results obtained by different operators using the same measuring equipment to measure the same object. The formula for calculating GR&R values ​​is relatively common and can also be calculated using software such as Minitab. For example, after copying data from the system repeatability and reproducibility analysis data table to Minitab, the calculation can be performed using the path: Statistics - Quality Tools - Gauge Study - Gauge R&R Study. This method demonstrates the ability to determine the deviation of the measurement system and the repeatability and reproducibility of the measurement results, thereby guiding how to improve and optimize the pressure probe.

[0097] In some optional embodiments of the first aspect of this application, in each automatic continuous EL test, the EL testing machine is set to an automatic detection state, and an operator feeds c efficiency mainstream test pieces in sequence and automatically transfers them into the EL testing machine. The probe assembly is automatically controlled to press down on the efficiency mainstream test pieces, and all probe rows in the probe assembly are electrically connected to the multiple main grids of the efficiency mainstream test pieces one-to-one, so as to perform EL testing on the efficiency mainstream test pieces.

[0098] In some optional embodiments of the first aspect of this application, the comparative EL test before and after the reduction of the number of probe rows includes:

[0099] The EL testing machine with the original M probe rows is calibrated using a standard sheet to ensure that the calibration value is within the range required by the standard sheet. Then, f third cells that have passed the EL test on the production line are selected and EL tested on the EL testing machine with the original M probe rows respectively. The first average value X1 of the cell conversion efficiency of the f third cells is calculated.

[0100] The standard sheet is used to calibrate the EL tester with M' probe rows. f third cells that have passed the EL test on the production line are taken and EL tested on the EL tester with M' probe rows respectively. The second average value X2 of the cell conversion efficiency of the f third cells is calculated.

[0101] The absolute value of the difference between the first average value X1 and the second average value X2 is less than 0.05%.

[0102] In these embodiments, when the absolute value of the difference between the first average value X1 and the second average value X2 is less than 0.05%, it indicates that the difference between the original number of probe rows and the optimized number of probe rows has little impact on the efficiency difference, thus verifying the authenticity of the test data.

[0103] In one specific example of these embodiments, firstly, the test equipment with 11 main grids is calibrated using a standard sheet. The calibration value is within the required range of the standard sheet. Then, 20 sheets are selected for testing on this equipment, and the first average value X1 of the 20 sheets is summarized. Secondly, following the same method, the test equipment with 5 main grids is calibrated using a standard sheet. The calibration value is also within the required range of the standard sheet. The 20 sheets are then selected for testing on the 5 main grids test equipment, and the second average value X2 of the 20 sheets is summarized. The absolute value of the difference between the first average value X1 and the second average value X2 is less than 0.05%.

[0104] In some optional embodiments of the first aspect of this application, gradually reducing the number of probe arrays includes:

[0105] Reduce the number of probe rows closest to the edge of the cell, and when the total number of reduced probe rows is greater than 1, at least two of the reduced probe rows are spaced apart on the original set of M probe rows.

[0106] In these embodiments, the original setup of multiple probe rows caused the main grid position to darken due to obstruction. Reducing the number of probe rows can reduce the overall problem of the probe rows obstructing the cells, which leads to the failure of EL testing to effectively identify cell abnormalities. Reducing the number of probe rows closest to the edge of the cell can specifically prevent the slight black edge of the cell parallel to the edge of the main grid from being obstructed by the probe rows.

[0107] In some optional embodiments of the first aspect of this application,

[0108] When the total number of reduced probe rows is greater than 1, all reduced probe rows are evenly spaced apart from the original set of M probe rows.

[0109] In these embodiments, the uniform spacing between all probe rows in the optimized probe assembly helps to ensure a stable voltage is applied to the solar cell during EL testing. This allows non-equilibrium carriers injected into the solar cell to be emitted as photons. The photon detector can capture the photons well, obtaining a visual image that fully reflects the defects and faults of the solar cell. This enables more effective and accurate identification of issues such as slight black edges, slight grid breaks, and blackening at the grid position on the parallel main grid edge of the solar cell, preventing problematic solar cells from flowing into the module.

[0110] like Figure 4 As shown, in some examples, the number of probes in row 1 before optimization is 11. Figure 4 Left small Figure 4 As shown in a, the number of probes in row 1 after optimization is 5. Figure 4 right small Figure 4 As shown in Figure b, a main grid line 21 is spaced apart between every two probe rows 1, and no corresponding probe row 1 is set on the main grid line 21 closest to the edge of the cell 2. In this example, the occlusion of the probe rows 1 on the main grid is reduced during EL testing, while ensuring better EL testing to identify and control the quality of the cell.

[0111] In EL testing, probe row 1 is sometimes specified to be replaced every 60 days. Reducing the number of probe row 1s can save on the consumption of probe row 1s on the production line and reduce production costs.

[0112] Taking a solar cell with 11 main busbars on the production line as an example, at the solar cell production end, after optimizing the number of probe bars on the EL testing machine using the probe bar number optimization method in the first aspect of this application, the proportion of broken grids inside the solar cell detected by EL testing increased from 0.37% to 0.39%, proving that more abnormal solar cells with blackened broken grids were detected. Meanwhile, the proportion of broken grids at the module end decreased from 0.02% to 0.01%, effectively demonstrating that this optimization method effectively prevents abnormal solar cells from flowing into the module end, greatly reducing the customer complaint rate and reducing compensation losses at the external module end.

[0113] The second aspect of this application provides an EL testing machine, which has a probe assembly including multiple probe rows. The probe rows are positioned above the solar cell during the EL test, and all probe rows in the probe assembly are electrically connected to multiple main grids on the solar cell in a one-to-one correspondence. The ratio of the number of probe rows in the probe assembly to the number of main grid lines on the solar cell tested by the EL testing machine is 0.3 to 0.6.

[0114] In some cases, the number of probe rows in the probe assembly of the EL testing machine is reduced after optimization using the probe row number optimization method in the EL testing of the first aspect of this application.

[0115] In some optional embodiments of the second aspect of this application, the probe rows in the probe assembly are evenly spaced in the multiple probe row arrangement directions, and there is at least one main grid line between every two adjacent probe rows.

[0116] In these embodiments, the probe arrays are spaced apart to avoid severe concentrated shading of a certain area of ​​the solar cell, and to ensure high-quality contact between the solar cell and the probe assembly during the EL test, thereby ensuring smooth electrical signal transmission during the EL test and thus guaranteeing the accuracy and reliability of the test results.

[0117] In some optional embodiments of the second aspect of this application, in the arrangement direction of the multiple probe rows, the outermost row of probe rows is spaced apart from the edge of the corresponding cell by at least one main grid line. In these embodiments, not having a probe row corresponding to the main grid line closest to the edge of the cell can specifically avoid the slight black edge of the cell parallel to the edge of the main grid being obscured by the probe row, allowing for better observation of the slight black edge of the cell during EL testing.

[0118] In some optional embodiments of the second aspect of this application, the probe assembly is provided with 4 to 10 probe rows. The probe assembly is provided with 4, 5, 6, 7, 8, 9, or 10 probe rows. Through optimization, it has been found that, for example, when performing EL testing on a solar cell with 11 main busbars, a probe row count of 5 can effectively identify and control various abnormal solar cells such as blackening and broken grids during EL testing, ensuring that high-quality solar cells flow into the module production end.

[0119] The EL testing machine provided in the second aspect of this application optimizes the number of probe rows in the EL testing using the method for optimizing the number of probe rows in the first aspect of this application. While ensuring high-quality and effective EL testing, it effectively controls solar cells that fail to be effectively identified due to blackening abnormalities during EL testing caused by probe row obstruction. It also reduces the number of probe row replacements required for solar cells, saves production costs, and improves the quality control of finished solar cells. This is conducive to further improving the quality of photovoltaic modules and enhancing customer satisfaction.

[0120] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for optimizing the number of probe rows in EL testing, characterized in that, include: Based on the conventionally set number of probe rows M in the original probe assembly of the EL testing machine, the number of probe rows is gradually reduced. Multi-dimensional EL testing of solar cells is performed using the probe assembly after each reduction in probe rows. If the test results for each dimension of the solar cell meet the corresponding preset values, the current number of probe rows in the probe assembly is further reduced. The test continues until at least one dimension of the multi-dimensional solar cell EL test fails to meet the corresponding preset value. Then, the current number of probe arrays is recorded as N, and the number of probe arrays in the previous multi-dimensional solar cell EL test is recorded as N', where N and N' are both natural numbers. If the difference between N and N' is 1, then N' is the optimized value Y for the number of probe rows; if the difference between N and N' is greater than 1, then the optimized value Y for the number of probe rows is determined in the numerical range with N and N' as endpoints. The determination condition is: the test results of each dimension of the battery cell in the multi-dimensional battery cell EL test using Y probe rows meet the corresponding preset value, and the test results of at least one dimension of the battery cell in the multi-dimensional battery cell EL test using Y-1 probe rows do not meet the corresponding preset value. The multi-dimensional EL testing of solar cells includes: manual static EL testing of solar cells on an EL testing machine, automatic dynamic EL testing of solar cells on an EL testing machine, GR&R testing of EL testing machines after the number of probe rows is reduced, and comparative EL testing before and after the number of probe rows is reduced.

2. The method for optimizing the number of probe arrays in EL testing according to claim 1, characterized in that, The manual static EL test of the solar cells on the EL testing machine includes: The first battery cell that passed the EL test on the production line is placed on the EL testing machine under the probe assembly. The probe assembly is manually pressed down onto the first battery cell and then left to stand still. All the probe rows in the probe assembly are electrically connected to the multiple main grids of the first battery cell. In the standing state, 'a' EL tests are performed on the first battery cell continuously to obtain the battery conversion efficiency for each EL test. Calculate the first overall battery conversion efficiency range in a EL test. When the first overall battery conversion efficiency range is less than the preset value of the first battery conversion efficiency range, it is determined that the cell test result in this dimension meets the corresponding preset value. Preferably, the preset value for the conversion efficiency range of the first battery is 0.02%; Preferably, the value of a ranges from 10 to 15.

3. The method for optimizing the number of probe arrays in EL testing according to claim 1, characterized in that, The automatic dynamic EL testing of the solar cells on the EL testing machine includes: Select the second battery cell that has passed the EL test on the production line, set the EL test machine to automatic detection state, repeat the automatic EL test b times and calculate the range of conversion efficiency of the second overall battery in the b automatic EL test. When the range of conversion efficiency of the second overall battery is less than the preset value of the range of conversion efficiency of the second battery, it is determined that the battery cell test result in this dimension meets the corresponding preset value. An automated EL test includes: the second solar cell is automatically fed into the EL testing machine, the probe assembly is automatically controlled to press down on the second solar cell, and all the probe rows in the probe assembly are electrically connected to the multiple main grids of the second solar cell one by one to perform EL testing on the second solar cell; Preferably, the preset value for the conversion efficiency range of the second battery is 0.04%; Preferably, the value of b is in the range of 10 to 15.

4. The method for optimizing the number of probe arrays in EL testing according to claim 1, characterized in that, The GR&R test for the EL testing machine after the reduction of the number of probe rows includes: Prepare c mainstream performance test chips; d operators will be randomly selected; Each operator performs e rounds of automatic continuous EL testing on the c mainstream efficiency test pieces. The total amount of EL test efficiency data I obtained is the product of d, c, and e. Based on the EL test efficiency data volume I, calculate the EL testing machine variation (EV) reflecting repeatability and the evaluator variation (AV) reflecting reproducibility, according to R&R. 2 =EV 2 +AV 2 The GR&R value is calculated. When the GR&R value is less than the preset value of the tolerance of the battery cell test data specification, it is determined that the battery cell test result in this dimension meets the corresponding preset value. Preferably, the preset value for the tolerance of the battery cell test data specification is 10%; Preferably, the value of c ranges from 10 to 20, the value of d ranges from 3 to 5, and the value of e ranges from 3 to 10; Preferably, in each round of the automatic continuous EL test, the EL testing machine is set to an automatic detection state, and an operator feeds c efficiency mainstream test pieces in sequence and automatically transfers them into the EL testing machine. The probe assembly is automatically controlled to press down on the efficiency mainstream test pieces, and all the probe rows in the probe assembly are electrically connected to the multiple main grids of the efficiency mainstream test pieces in a one-to-one correspondence, so as to perform EL testing on the efficiency mainstream test pieces.

5. The method for optimizing the number of probe arrays in EL testing according to claim 1, characterized in that, The comparative EL tests before and after reducing the number of probe rows include: The EL testing machine with the original M probe arrays is calibrated using a standard sheet to ensure that the calibration value is within the required range of the standard sheet. Then, f third cells that have passed the EL test on the production line are selected and subjected to EL test on the EL testing machine with the original M probe arrays. The first average value X1 of the cell conversion efficiency of the f third cells is calculated. The EL testing machine with M' probe rows is calibrated using a standard sheet. The f third cells that have passed the EL test on the production line are then subjected to EL tests on the EL testing machine with M' probe rows, and the second average value X2 of the cell conversion efficiency of the f third cells is calculated. M' is the number of probe rows in the current probe assembly after each reduction of probe rows. When the absolute value of the difference between the first average value X1 and the second average value X2 is less than a preset value, it is determined that the battery cell test result in this dimension meets the corresponding preset value. Preferably, the preset value of the absolute value is 0.05%.

6. The method for optimizing the number of probe arrays in EL testing according to claim 1, characterized in that, The gradual reduction in the number of probe rows includes: Reduce the number of probe rows closest to the edge of the battery cell; Furthermore, when the total number of reduced probe rows is greater than 1, at least two of the reduced probe rows are spaced apart on the original set of M probe rows.

7. The method for optimizing the number of probe arrays in EL testing according to claim 6, characterized in that, When the total number of reduced probe rows is greater than 1, all the reduced probe rows are evenly spaced among the original M probe rows.

8. An EL testing machine, characterized in that, The EL testing machine has a probe assembly, which includes multiple probe rows. During the EL testing process, the probe rows are positioned above the solar cell, and all the probe rows in the probe assembly are electrically connected to multiple main grids on the solar cell in a one-to-one correspondence. The ratio of the number of probe rows in the probe assembly to the number of main grid lines on the solar cell tested by the EL testing machine is 0.3 to 0.

6.

9. The EL testing machine according to claim 8, characterized in that, In the direction of the arrangement of the multiple probe rows, the probe rows in the probe assembly are evenly spaced, and there is at least one main grid line between every two adjacent probe rows.

10. The EL testing machine according to claim 8 or 9, characterized in that, In the arrangement direction of the multiple probe rows, the outermost probe row is spaced apart from the edge of the corresponding battery cell by at least one main grid line.

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