Method for evaluating quality of photovoltaic module

Abstract

The invention discloses a method for evaluating the quality of a photovoltaic module. The evaluation method comprises the following steps: before a sequence aging test, heating a to-be-tested photovoltaic module, and performing a power test on the to-be-tested photovoltaic module to obtain a first power test result; after the sequence aging test, performing EL test and power test on the to-be-tested photovoltaic module under a T98% temperature condition to obtain a first EL test result and a second power test result; the defect percentage is calculated according to a second EL test result and the first EL test result of the photovoltaic module to be tested under the STC, and the second EL test result is obtained before the sequence aging test; calculating the power attenuation of the to-be-tested photovoltaic module under the T98% temperature condition by using the first power test result and the second power test result; and evaluating the quality of the photovoltaic module to be tested by using the defect percentage and the power attenuation. The evaluation method can effectively improve the accuracy and integrity of quality evaluation of the photovoltaic module.

Description

Technical Field

[0001] The present invention relates to a method for evaluating the quality of photovoltaic modules. Background Art

[0002] For photovoltaic modules, currently, the IEC standard is generally used to test performances such as power, insulation, wet leakage current, aging or light stability, etc., and the quality of photovoltaic modules is evaluated based on the test results. The IEC standard is a series of international standards designated and issued by the International Electrotechnical Commission (IEC).

[0003] Specifically, the test process of the IEC standard: initial appearance inspection → initial light stability → power and electroluminescence (EL) tests under standard test conditions (STC, where STC usually refers to a light intensity of 1000 W / m 2 , a spectral distribution of AM (air mass) 1.5, and a module temperature of 25°C) → insulation test → wet leakage current test → sequential aging test → final light temperature → power and EL tests under STC → insulation test → wet leakage current test. That is to say, one of the main means of the existing IEC standard to evaluate the quality and health of photovoltaic modules is completed through the power and EL tests under STC before the sequential aging test and the power and EL tests under STC after the sequential aging test. The power and EL tests under STC after the sequential aging test are completed at a module temperature of 25°C, which cannot truly reflect the power and EL of photovoltaic modules at the aging temperature, resulting in room for improvement in the accuracy and integrity of the quality evaluation of photovoltaic modules. Summary of the Invention

[0004] In view of this, the present invention provides a method for evaluating the quality of photovoltaic modules, which can effectively improve the accuracy and integrity of the quality evaluation of photovoltaic modules.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] A method for evaluating the quality of photovoltaic modules, comprising:

[0007] Step 1: Before the sequential aging test, heat up the photovoltaic module to be tested, and perform a power test on the photovoltaic module to be tested during the heating process to obtain the first power test result of the photovoltaic module to be tested;

[0008] Step 2: After the sequence aging test, under the T98% temperature condition, perform EL test and power test on the photovoltaic module to be tested after the aging test to obtain the first EL test result and the second power test result of the photovoltaic module to be tested. Herein, the T98% temperature condition means that under the measurement working condition, the temperature of at least 98% of the temperature measurement position points among multiple temperature measurement position points is not lower than the set temperature threshold;

[0009] Step 3: Use the second EL test result and the first EL test result of the photovoltaic module to be tested under STC to calculate the defect percentage of the photovoltaic module to be tested. Herein, the second EL test result is obtained before the sequence aging test;

[0010] Step 4: Use the first power test result and the second power test result to calculate the power attenuation of the photovoltaic module to be tested under the T98% temperature condition;

[0011] Step 5: Use the defect percentage and the power attenuation of the photovoltaic module to be tested to evaluate the quality of the photovoltaic module to be tested.

[0012] The technical solution of the first aspect of the above invention has the following advantages or beneficial effects:

[0013] In the technical solution provided by the embodiment of the present invention, before the sequence aging test, add the step of performing power test on the photovoltaic module to be tested during the heating process to obtain the first power test result of the photovoltaic module to be tested. After the sequence aging test, add the steps of performing EL test and power test on the photovoltaic module to be tested after the aging test under the T98% temperature condition to obtain the first EL test result and the second power test result of the photovoltaic module to be tested. Calculate the defect percentage of the photovoltaic module to be tested through the first EL test result and the second EL test result of the photovoltaic module to be tested under STC, calculate the power attenuation of the photovoltaic module to be tested under the T98% temperature condition by using the first power test result and the second power test result, and use the defect percentage and the power attenuation under the T98% temperature condition to evaluate the quality of the photovoltaic module to be tested. Performing power test on the photovoltaic module to be tested during the heating process and performing EL test and power test on the photovoltaic module to be tested after the aging test under the T98% temperature condition can more truly reflect the performance of the photovoltaic module at the working temperature. Based on this, evaluating the photovoltaic module can effectively improve the accuracy and integrity of the quality evaluation of the photovoltaic module. Description of the Drawings

[0014] Figure 1 is a main process schematic diagram of the method for evaluating the quality of a photovoltaic module according to an embodiment of the present invention;

[0015] Figure 2 It is a schematic diagram of the main process for calculating the defect percentage of a photovoltaic module to be tested according to an embodiment of the present invention;

[0016] Figure 3 It is a schematic diagram of the EL image of a photovoltaic module for the EL test of the photovoltaic module at 25°C according to an embodiment of the present invention;

[0017] Figure 4 It is a schematic diagram of the EL image of a photovoltaic module for the EL test of the photovoltaic module at T98% according to an embodiment of the present invention;

[0018] Figure 5 It is a schematic diagram of the main process for calculating the power attenuation of a photovoltaic module to be tested under the temperature condition of T98% according to an embodiment of the present invention;

[0019] Figure 6 It is a schematic diagram of the main process for an evaluation method of the quality of a photovoltaic module according to another embodiment of the present invention. Detailed implementation manners

[0020] Photovoltaic modules with excellent weather resistance and reliability are the basic requirements of photovoltaic power stations for photovoltaic modules. Based on this, a series of environmental reliability tests need to be carried out on photovoltaic modules to evaluate and determine whether the photovoltaic modules meet the requirements of photovoltaic power stations. As described in the background art, currently, a series of international standards specified and issued by the International Electrotechnical Commission (IEC) are mainly adopted for the environmental reliability tests of photovoltaic modules. Specifically, the series of current tests for photovoltaic modules: initial appearance inspection → initial light stability → standard test condition (STC, this STC usually refers to the light intensity of 1000W / m 2, under the conditions of spectral distribution being AM (Air Mass) 1.5 and module temperature being 25°C, power and EL tests → insulation test → wet leakage current test → sequential aging test → final light temperature → power and EL tests under STC → insulation test → wet leakage current test. In particular, currently, for the sequential aging test, after a series of aging treatments such as ultraviolet light irradiation and temperature rise aging on the photovoltaic module, the power and / or EL tests are carried out after the temperature of the photovoltaic module drops to room temperature. That is, it can be seen from the existing IEC standard test process that these test results are basically the test results under room temperature environment (25°C). Although aging tests are carried out on the photovoltaic module, the power test and EL test after the aging test are still completed under room temperature environment (25°C), which cannot truly reflect the performance (power and EL) of the photovoltaic module at the working temperature (generally, the working temperature of the photovoltaic module is higher than 25°C, such as 60°C, 70°C, 80°C or 90°C, etc.). Therefore, the existing test results do not test the performance of the photovoltaic module at the working temperature, resulting in room for improvement in the accuracy and reliability of the test results.

[0021] The sequential aging test involved in the embodiments of the present invention refers to performing relevant sequential aging tests on the photovoltaic module in accordance with the IEC61215 standard, including hot spot tests under sunlight exposure and tests of placing the photovoltaic module in high and low temperature environments, etc., to evaluate the performance of the photovoltaic module in its working environment.

[0022] The T98% temperature condition involved in the embodiments of the present invention means that under the measurement conditions, the temperature of at least 98% of the temperature measurement position points among multiple temperature measurement position points is not lower than the set temperature threshold. That is to say, under the measurement conditions, a temperature threshold is set for multiple temperature measurement position points of the photovoltaic module, and among them, the temperature of at least 98% of the temperature measurement position points is not lower than the set temperature threshold. Generally speaking, when the temperature of at least 98% of the temperature measurement position points is not lower than the set temperature threshold, the temperature of this at least 98% of the temperature measurement position points is basically near the temperature threshold. Therefore, this T98% temperature condition can also be considered that the temperature of 98% of the temperature measurement position points reaches the temperature threshold, which can be used to characterize that the temperature of the photovoltaic module reaches this temperature threshold. For example, when measuring the temperature of 100 temperature measurement position points of the photovoltaic module, and the temperature of 98 temperature measurement position points is not lower than the set temperature threshold, then the photovoltaic module is under the T98% temperature condition, and it can also be considered that the temperature of 98% of the temperature measurement position points reaches the temperature threshold; another example is when measuring the temperature of 50 temperature measurement position points of the photovoltaic module, and the temperature of 49 temperature measurement position points is not lower than the set temperature threshold, then the photovoltaic module is under the T98% temperature condition, and it can also be considered that the temperature of 98% of the temperature measurement position points reaches the temperature threshold.

[0023] It should be noted that the temperature threshold can be set flexibly. For example, according to actual requirements, the temperature thresholds for different processing stages can be set. For example, the temperature threshold corresponding to the T98% temperature condition used after the sequence aging test can be set, and the temperature thresholds for each T98% temperature condition corresponding to multiple heating gradients before the sequence aging test, etc. In addition, for the same batch of photovoltaic modules, the temperature threshold corresponding to the same processing stage or processing step is generally relatively fixed. For different batches of photovoltaic modules, the temperature threshold can be adjusted.

[0024] In addition, multiple temperature measurement position points are generally the position points selected for the photovoltaic module to measure the temperature. The number of temperature measurement position points selected for the photovoltaic module can be determined according to the size and measurement requirements of the photovoltaic module. Here, the number of temperature measurement position points is not limited.

[0025] The power test involved in the embodiments of the present invention refers to performing a current-voltage characteristic test on a photovoltaic module at an arbitrarily set temperature. Specifically, the photovoltaic module is irradiated with a solar simulator under a set light intensity and a set irradiation intensity, and after the temperature of the photovoltaic module reaches the set temperature (the set temperature can be normal temperature such as 25°C or the operating temperature), the maximum power of the photovoltaic module is measured.

[0026] The electroluminescent (EL) test involved in the embodiments of the present invention is to apply a certain voltage across the two ends of the photovoltaic module to excite electrons inside the photovoltaic module to emit visible light. The intensity and distribution of these visible lights can be reflected in the gray-scale changes of the image of the photovoltaic module captured by the camera. In the technical solution provided by the embodiments of the present invention, an image of the photovoltaic module at any operating temperature can be captured. The EL test uses the gray scale of each position of the image of the photovoltaic module captured at 25°C as the test reference or uses a pre-set image gray scale value or image brightness value as the reference.

[0027] Next, the method for evaluating the quality of the photovoltaic module provided by the embodiments of the present invention will be described in detail. As Figure 1 shown, the method for evaluating the quality of the photovoltaic module may include the following steps:

[0028] Step S101: Before the sequence aging test, heat up the photovoltaic module to be tested, and perform a power test on the photovoltaic module to be tested during the heating process to obtain the first power test result of the photovoltaic module to be tested.

[0029] Among them, the photovoltaic module to be tested refers to the photovoltaic module produced by the photovoltaic module production process and requires a series of performance tests before being applied to a photovoltaic power station.

[0030] Heating the photovoltaic module to be tested and performing a power test on the photovoltaic module to be tested during the heating process means that under the irradiation of the light emitted by the solar simulator, the photovoltaic module to be tested is heated, and during the heating process of the photovoltaic module, the maximum power of the photovoltaic module under the test standard spectral conditions (the standard spectral conditions generally refer to the light intensity of 1000W / m 2 , and the spectral distribution is AM (Air Mass) 1.5) is measured.

[0031] In the process of performing a power test on the photovoltaic module to be tested during the heating process as described above, the first power test result includes the maximum power of the photovoltaic module under the standard spectral conditions measured at multiple heating temperatures during the heating process of the photovoltaic module. Among them, the maximum power of the photovoltaic module under the standard spectral conditions is completed by existing test equipment and will not be elaborated here.

[0032] Furthermore, for the method of evaluating the quality of the photovoltaic module, before this step S101, it may also include: sequentially performing an appearance inspection, an initial light stability test, a power test under STC conditions, and an EL test on the photovoltaic module to be tested. The appearance inspection, the initial light stability test, the power test under STC conditions, and the EL test can all be realized by existing test means and will not be elaborated here.

[0033] By performing a power test on the photovoltaic module to be tested during the heating process before the sequential aging, the test is carried out at the working temperature of the photovoltaic module to be tested, so that the first power test result can more truly reflect the real situation of the photovoltaic module to be tested at the working temperature.

[0034] Step S102: After the sequential aging test, under the T98% temperature condition, perform an EL test and a power test on the photovoltaic module to be tested after the aging test to obtain the first EL test result and the second power test result of the photovoltaic module to be tested. Among them, the T98% temperature condition means that under the measurement working condition, the temperature of at least 98% of the temperature measurement position points among multiple temperature measurement position points is not lower than the set temperature threshold.

[0035] This step is to perform an EL test and a power test on the photovoltaic module to be tested after the aging test under the T98% temperature condition. Compared with the test at room temperature (25°C), the photovoltaic module to be tested under the T98% temperature condition can more truly reflect the real working condition of the photovoltaic module to be tested after aging, and improve the accuracy and reliability of the subsequent evaluation of the quality of the photovoltaic module to be tested.

[0036] The first EL test result and the second power test result are obtained under the T98% temperature condition, which can more truly reflect the working condition of the photovoltaic module to be tested.

[0037] Among them, the set temperature threshold corresponding to the above T98% temperature condition can be set by the user according to experience for the photovoltaic module to be tested, or it can be the temperature threshold that can be satisfied by 98% or more of the position points statistically obtained based on the test results of multiple temperature tests at multiple position points on the photovoltaic module to be tested.

[0038] The first EL test result includes an image or grayscale image containing the photovoltaic module to be tested obtained by photographing the photovoltaic module to be tested after the aging test under the T98% temperature condition.

[0039] Among them, the second power test result includes the maximum power of the photovoltaic module based on the photovoltaic module to be tested under the T98% temperature condition and the standard spectral condition.

[0040] Step S103: Calculate the defect percentage of the photovoltaic module to be tested by using the first EL test result and the second EL test result of the photovoltaic module to be tested under the STC condition, where the second EL test result is obtained before the sequential aging test.

[0041] Among them, the second EL test result includes an image or grayscale image containing the photovoltaic module to be tested obtained by photographing the photovoltaic module to be tested before the aging test under the STC condition.

[0042] The defect percentage of the photovoltaic module to be tested calculated in this step, due to the introduction of the first EL test result obtained under the T98% temperature condition, enables the defect percentage of the photovoltaic module to be tested to more truly reflect the defects under the working state of the photovoltaic module to be tested.

[0043] Step S104: Calculate the power attenuation of the photovoltaic module to be tested under the T98% temperature condition by using the first power test result and the second power test result.

[0044] What this step calculates is the power attenuation of the photovoltaic module to be tested under the T98% temperature condition, that is, it reflects the power attenuation of the photovoltaic module to be tested under the working environment, and it can more accurately and truly reflect the working condition of the photovoltaic module to be tested.

[0045] Step S105: Evaluate the quality of the photovoltaic module to be tested by comprehensively considering the defect percentage and power attenuation of the photovoltaic module to be tested.

[0046] Since the defect percentage of the photovoltaic module to be tested can more truly reflect the defects under the working state of the photovoltaic module to be tested, and the power attenuation of the photovoltaic module to be tested reflects the power attenuation of the photovoltaic module to be tested under the working environment, by comprehensively considering the defect percentage and power attenuation, the working condition of the photovoltaic module to be tested can be better evaluated, making the evaluation result more accurate.

[0047] In summary, for Figure 1 the provided technical solution, before the sequence aging test, a step of performing a power test on the photovoltaic module to be tested during the heating process is added to obtain the first power test result of the photovoltaic module to be tested. After the sequence aging test, steps of performing an EL test and a power test on the photovoltaic module to be tested after the aging test under the T98% temperature condition are added to obtain the first EL test result and the second power test result of the photovoltaic module to be tested. The defect percentage of the photovoltaic module to be tested is calculated through the first EL test result and the second EL test result of the photovoltaic module to be tested under STC. The power attenuation of the photovoltaic module to be tested under the T98% temperature condition is calculated using the first power test result and the second power test result. The quality of the photovoltaic module to be tested is evaluated using the defect percentage and the power attenuation under the T98% temperature condition. Performing a power test on the photovoltaic module to be tested during the heating process and performing an EL test and a power test on the photovoltaic module to be tested after the aging test under the T98% temperature condition can more truly reflect the performance of the photovoltaic module at the working temperature. Evaluating the photovoltaic module based on this can effectively improve the accuracy and integrity of the quality evaluation of the photovoltaic module.

[0048] In addition, the technical solution provided in the embodiment of the present invention can more fully evaluate the performance of the photovoltaic module, can additionally identify problems such as defects in photovoltaic modules that are qualified under conventional IEC tests at high temperatures and unqualified actual power generation, and avoid problems such as excessive power attenuation in the subsequent actual application of the photovoltaic module.

[0049] The above steps S101, S103, S104, and S105 will be described in detail below.

[0050] There are two specific implementation manners for the above step S101 to perform a power test on the photovoltaic module to be tested during the heating process.

[0051] Specifically, the first specific implementation manner of the above step S101 to perform a power test on the photovoltaic module to be tested during the heating process: perform a power test on the photovoltaic module to be tested under the T98% temperature condition. Among them, the first power test result is the first power of the photovoltaic module to be tested under the T98% temperature condition, that is, the maximum power of the photovoltaic module under the T98% temperature condition and the standard spectral condition. Among them, the T98% temperature condition can be 60°C, 70°C, 80°C, or 90°C, etc. Compared with performing a power test on the photovoltaic module to be tested at multiple heating temperatures, performing a power test on the photovoltaic module to be tested under the T98% temperature condition is convenient for operation.

[0052] The second specific implementation manner of step S101 for performing a power test on a photovoltaic module to be tested during the heating process: perform a power test on the photovoltaic module to be tested at multiple heating temperatures. Among them, the first power test result is the third power of the photovoltaic module to be tested at each heating temperature. Among them, the multiple heating temperatures are heating based on 25°C, and the heating temperature can be controlled by a computer program. The heating temperature can be 40°C, 45°C, 50°C, 60°C, 65°C, 70°C, 75°C, 80°C, or 90°C, etc. The third power at each heating temperature is the power corresponding to 40°C, the power corresponding to 45°C, the power corresponding to 50°C, the power corresponding to 60°C, the power corresponding to 65°C, the power corresponding to 70°C, the power corresponding to 75°C, the power corresponding to 80°C, or the power corresponding to 90°C, etc.

[0053] Regarding performing a power test on the photovoltaic module to be tested at multiple heating temperatures, preferably, the photovoltaic module to be tested is heated from 25°C to 105°C according to a preset heating gradient, and at each preset heating gradient, a power test is performed on the photovoltaic module to be tested. There can be multiple preset heating gradients. More preferably, the multiple preset heating gradients may include: at least 98% of the temperature measurement position points are heated from 25°C to the first temperature range, the minimum value of the first temperature range is greater than 25°C and the maximum value of the first temperature range does not exceed 70°C (exemplarily, the first temperature range can be 30°C - 70°C, 30°C - 40°C, or 50°C - 70°C, etc.); at least 98% of the temperature measurement position points are heated from the first temperature range to the second temperature range, the minimum value of the second temperature range is greater than 70°C and the maximum value of the second temperature range does not exceed 80°C (exemplarily, the second temperature range can be 75°C - 80°C, 71°C - 78°C, or 74°C - 80°C, etc.); at least 98% of the temperature measurement position points are heated from the second temperature range to the third temperature range, the minimum value of the third temperature range is greater than 80°C and the maximum value of the third temperature range does not exceed 90°C (exemplarily, the third temperature range can be 84°C - 90°C, 81°C - 88°C, or 85°C - 90°C, etc.); at least 98% of the temperature measurement position points are heated from the third temperature range to the fourth temperature range, the minimum value of the fourth temperature range is greater than 90°C and the maximum value of the third temperature range does not exceed 105°C (exemplarily, the fourth temperature range can be 92°C - 105°C, 95°C - 100°C, or 98°C - 105°C, etc.). Compared with the third power at the temperature points (such as 70°C, 75°C, 80°C, or 90°C, etc.) of each heating temperature above, by following multiple preset heating gradients and each preset heating gradient being a temperature range, the test difficulty can be reduced, the test operability can be improved, and the accuracy of subsequent evaluation can be ensured.

[0054] Further, as Figure 2 shown, the specific implementation manner of step S103 above may include the following steps:

[0055] Step S1031: Calculate the newly added defect amount of the photovoltaic module to be tested under the T98% temperature condition by using the second EL test result and the first EL test result.

[0056] Specifically, in this step, the area where the brightness change value exceeds 5 is determined as the defect area through the HSL (Hue, Saturation, Lightness) color recognition method. Among them, the brightness change value is calculated based on the image included in the second EL test result of the photovoltaic module to be tested under STC or the preset basic brightness value, and the brightness change value of the image included in the first EL test result of the photovoltaic module to be tested obtained under the T98% temperature condition is calculated, that is, the brightness value of a specific position or specific area in the image included in the first EL test result of the photovoltaic module to be tested obtained under the T98% temperature condition is subtracted from the brightness value of the same specific position or specific area in the image included in the second EL test result of the photovoltaic module to be tested under STC to obtain the brightness change value, or the brightness value of a specific position or specific area in the image included in the first EL test result of the photovoltaic module to be tested obtained under the T98% temperature condition is subtracted from the basic brightness value to obtain the brightness change value.

[0057] Among them, the brightness value of a specific position or specific area in the image can be directly determined based on the HSL of the image, or can be determined based on the value after correcting the HSL of the specific position or specific area in the image through a trained model. Among them, the specific position or specific area can be multiple positions or areas divided by the user according to needs in the image, and does not specifically refer to a fixed position or a fixed area.

[0058] Specifically, there are two specific implementation methods for the above step S1031.

[0059] The first specific implementation method of the above step S1031 may include the following steps:

[0060] Step S1031-1: Divide the photovoltaic module to be tested into grids.

[0061] As Figure 3 shown in the image of the photovoltaic module to be tested included in the second EL test result under STC and Figure 4 shown in the image of the photovoltaic module to be tested included in the first EL test result under the T98% temperature condition. The image is cut into each grid, and the grid size can be set according to needs.

[0062] Step S1031-2: Use the HSL color recognition method to respectively identify the number of the first grids containing defects in the first EL test result and the number of the second grids containing defects in the second EL test result.

[0063] Among them, the number of the first defective grids is determined based on a preset basic brightness value. That is, if the difference between the brightness value of a grid in the first EL test result and the basic brightness value exceeds 5, it is determined that the grid contains a defect. The number of grids in the first EL test result whose brightness value and the basic brightness value difference exceeds 5 is the number of the first defective grids in the first EL test result. The number of the second defective grids in the second EL test result is also determined based on a preset basic brightness value. That is, if the difference between the brightness value of a grid in the second EL test result and the basic brightness value exceeds 5, it is determined that the grid contains a defect. The number of grids in the second EL test result whose brightness value and the basic brightness value difference exceeds 5 is the number of the second defective grids in the second EL test result. Among them, the basic brightness value is obtained by statistically analyzing a large number of photovoltaic modules.

[0064] Step S1031-3: Calculate the number of newly added defective grids by using the number of the first grids and the number of the second grids.

[0065] That is, the number of the first grids minus the number of the second grids is the number of newly added defective grids.

[0066] In addition, it is also possible to directly use the brightness value of each grid in the second EL test result as a reference, and count the number of grids in the first EL test result whose difference between the brightness value of each grid and the brightness value of the corresponding grid in the second EL test result exceeds 5, which is the number of newly added defective grids. For example, Figure 4 the brightness value of the first grid in the first row of the shown image minus Figure 3 the brightness value of the first grid in the first row of the shown image. If the difference exceeds 5, then mark the first grid in the first row as a defective grid number; Figure 4 the brightness value of the second grid in the first row of the shown image minus Figure 3 the brightness value of the second grid in the first row of the shown image. If the difference is less than 5, then ignore it; and so on, Figure 4 the brightness value of the third grid in the first row of the shown image minus Figure 3 the brightness value of the third grid in the first row of the shown image, Figure 4 the brightness value of the fourth grid in the first row of the shown image minus Figure 3 the brightness value of the fourth grid in the first row of the shown image, ……, Figure 4 the brightness value of the tenth grid in the tenth row of the shown image minus Figure 3 the brightness value of the tenth grid in the tenth row of the shown image, etc. It should be noted that the calculation of the difference between the brightness values of each corresponding grid is generally carried out through multi-thread synchronization to effectively improve the calculation efficiency.

[0067] The second specific implementation manner of step S1031 may include the following steps:

[0068] Step S1031-1': Use the HSL color recognition method to respectively identify the second defect area of the second EL test result and the first defect area of the first EL test result.

[0069] Among them, the first defect area and the second defect area can be calculated based on the above-mentioned first grid number and second grid number and the area of the grid, or can be calculated based on the size of the defect area. Calculating the defect area through the size of the defect area can be obtained through existing area calculation formulas and will not be elaborated here.

[0070] Step S1031-2': Use the first defect area and the second defect area to calculate the new defect area of the photovoltaic module to be tested under the T98% temperature condition.

[0071] The new defect area is the value obtained by subtracting the second defect area from the first defect area.

[0072] Step S1032: Use the new defect amount of the photovoltaic module to be tested under the T98% temperature condition and the basic data of the photovoltaic module to be tested to calculate the defect percentage of the photovoltaic module to be tested. The basic data includes the area of the main surface of the photovoltaic module to be tested or the number of grids divided on the main surface of the photovoltaic module to be tested.

[0073] Based on the first specific implementation manner of the above step S1031, the specific implementation manner of step S1032 may include: for the case where the new defect amount is the number of new defect grids, use the number of new defect grids and the number of basic grids divided by the photovoltaic module to be tested to calculate the defect percentage of the photovoltaic module to be tested. That is, the number of new defect grids under the T98% temperature condition divided by the number of basic grids divided is the defect percentage of the photovoltaic module to be tested.

[0074] Based on the second specific implementation manner of this step S1031, the specific implementation manner of step S1032 may include: for the case where the new defect amount is the new defect area, use the new defect area of the photovoltaic module to be tested under the T98% temperature condition and the area of the photovoltaic module to be tested to calculate the defect percentage of the photovoltaic module to be tested. That is, the new defect area under the T98% temperature condition divided by the area of the photovoltaic module to be tested is the defect percentage of the photovoltaic module to be tested.

[0075] By calculating the defect percentage of the photovoltaic module to be tested as above, the condition of the photovoltaic module to be tested under the T98% temperature condition is considered, effectively improving the accuracy and reliability of the test result.

[0076] Further, for the above-mentioned step S104, there are also two specific implementation manners.

[0077] Specifically, the first specific implementation manner of step S104 may include: calculating the power attenuation by using the second power of the photovoltaic module to be tested under the T98% temperature condition in the first power and second power test results of the photovoltaic module to be tested under the T98% temperature condition.

[0078] That is, the power attenuation can be calculated by using the following calculation formula (1).

[0079]

[0080] Wherein, PL iv-T98％ represents the power attenuation calculated by the calculation formula (1); P 1iv-T98％ represents the first power of the photovoltaic module to be tested under the T98% temperature condition in the first power test result obtained before the sequence aging test; P 2iv-T98％ represents the second power of the photovoltaic module to be tested under the T98% temperature condition in the second power test result obtained under the T98% temperature condition after the sequence aging test.

[0081] Compared with the power at normal temperature (such as 25°C), through this process, the power attenuation of the photovoltaic module to be tested under the working environment (such as 60°C, 70°C, 80°C or 90°C, etc.) after the sequence aging test is realized, which can more truly reflect the working condition of the photovoltaic module to be tested.

[0082] It should be noted that the set temperature threshold corresponding to the T98% temperature condition corresponding to the first power in the first power test result is the same as the set temperature threshold corresponding to the T98% temperature condition corresponding to the second power in the second power test result, and the set temperature threshold corresponding to the T98% temperature condition can be 50°C, 60°C, 70°C, 80°C or 90°C, etc.

[0083] Such as Figure 5 shown, the second specific implementation manner of this step S104 may include the following steps:

[0084] Step S1041: Calculate the temperature coefficient change value of the photovoltaic module to be tested from the STC to the T98% temperature condition by using each heating temperature and the third power at each heating temperature.

[0085] The temperature increase is generally not less than two temperature fixed values or not less than two temperature increase gradients. Through each temperature increase (such as 30°C, 40°C, 45°C, 50°C, 60°C, 70°C, etc.) (or each temperature increase gradient) and the third power at each temperature increase (such as the third power at 30°C, the third power at 40°C, the third power at 45°C, the third power at 50°C, the third power at 60°C, the third power at 70°C, etc.) (or and the third power corresponding to the temperature reached by not less than 98% of the temperature measurement position points at each temperature increase gradient, and the temperature reached by the not less than 98% of the temperature measurement position points is within the temperature range corresponding to the corresponding temperature increase gradient), the curve relationship between temperature and the third power can be constructed. According to this curve relationship, the temperature coefficient change value of the photovoltaic module to be tested from the STC to the T98% temperature condition can be calculated.

[0086] Step S1042: Calculate the power attenuation by using the STC power attenuation, temperature coefficient change value, T98% temperature condition and the temperature corresponding to the STC of the photovoltaic module to be tested, where the STC power attenuation of the photovoltaic module to be tested is calculated based on the power of the photovoltaic module to be tested at STC before the sequential aging test and the power of the photovoltaic module to be tested at STC after the sequential aging test.

[0087] This step calculates the power attenuation by using the following calculation formula (2).

[0088] PL iv-T98％ ′ = PL iv-25℃ + Δδ × (T98% - 25°C) (2)

[0089] Among them, PL iv-T98％ ′ represents the power attenuation calculated by the calculation formula (2); PL iv-25℃ represents the STC power attenuation of the photovoltaic module to be tested; Δδ represents the temperature coefficient change value; T98% represents the T98% temperature condition (that is, the set operating temperature satisfied by not less than 98% of the test position points).

[0090] Among them, PL iv-25℃ can be calculated by the following calculation formula (3).

[0091]

[0092] Among them, PL iv-25℃ represents the STC power attenuation of the photovoltaic module to be tested calculated by the calculation formula (3); P 1iv-25℃ represents the STC power of the photovoltaic module to be tested obtained before the sequential aging test; P 2iv-25℃ represents the STC power of the photovoltaic module to be tested obtained after the sequential aging test.

[0093] Understandably, this Figure 5 second specific implementation manner of step S104 shown is completed based on the second specific implementation manner of the above step S101.

[0094] Specifically, for the above step S1041 of calculating the temperature coefficient change value of the photovoltaic module to be tested from the STC to the T98% temperature condition, its specific implementation manner may include the following steps:

[0095] Step S1041-1: Use each heating temperature and the third power at each heating temperature to calculate the first temperature coefficient of the photovoltaic module to be tested under STC and the second temperature coefficient of the photovoltaic module to be tested under the T98% temperature condition respectively.

[0096] Specifically, use each heating temperature and the third power at each heating temperature to construct a temperature-power correlation curve, and determine the first tangent line at the position point corresponding to STC (i.e., temperature 25°C) and its corresponding third power in this temperature-power correlation curve. The slope corresponding to this first tangent line is the first temperature coefficient under STC; the second tangent line at the position point corresponding to the T98% temperature condition and the third power under this T98% temperature condition in the temperature-power correlation curve. The slope corresponding to this second tangent line is the second temperature coefficient under the T98% temperature condition.

[0097] In addition, each heating temperature can be replaced with the temperature range corresponding to the heating gradient. Correspondingly, the third power at each heating temperature is the third power corresponding to the temperature range corresponding to each heating gradient. For the temperature range corresponding to the heating gradient, construct a temperature-power correlation curve with the temperature reached by no less than 98% of the temperature measurement points within this temperature range corresponding to the heating gradient and the third power of the photovoltaic module to be tested measured at this temperature. The determination of the first temperature coefficient under STC and the second temperature coefficient under the T98% temperature condition is the same as the determination process of the temperature-power correlation curve constructed using each heating temperature and the third power at each heating temperature, and will not be elaborated here.

[0098] Step S1041-2: Use the first temperature coefficient and the second temperature coefficient to calculate the temperature coefficient change value.

[0099] This calculated temperature coefficient change value is the second temperature coefficient minus the first temperature coefficient.

[0100] Further, the specific implementation of the above step S105 may include: when the defect percentage is less than or equal to 5% and the power attenuation is less than or equal to 5%, it is determined that the photovoltaic module to be tested is qualified in quality. That is to say, when the defect percentage is greater than 5%, or the power attenuation is greater than 5%, it is determined that the photovoltaic module to be tested is unqualified in quality.

[0101] Further, another embodiment of the present invention also provides a method for evaluating the quality of a photovoltaic module. As Figure 6 shown, the evaluation method may include the following steps:

[0102] Step S601: Conduct an appearance inspection on the photovoltaic module to be tested.

[0103] Step S602: After the appearance inspection in step S601 is qualified, conduct an initial light stability test on the photovoltaic module to be tested.

[0104] Step S603: After the initial light stability test in step S602 is qualified, conduct a power test and an EL test on the photovoltaic module to be tested under STC conditions to obtain the second EL test result of the photovoltaic module to be tested under STC.

[0105] Step S604: After the power test and the EL test in step S603 are qualified, heat up the photovoltaic module to be tested, and conduct a power test on the photovoltaic module to be tested during the heating process to obtain the first power test result of the photovoltaic module to be tested.

[0106] Step S605: Conduct a sequential aging test on the photovoltaic module to be tested.

[0107] Step S606: Under the T98% temperature condition, conduct an EL test and a power test on the photovoltaic module to be tested after the aging test to obtain the first EL test result and the second power test result of the photovoltaic module to be tested.

[0108] Step S607: Use the first EL test result and the second EL test result of the photovoltaic module to be tested under STC to calculate the defect percentage of the photovoltaic module to be tested.

[0109] Step S608: Use the first power test result and the second power test result to calculate the power attenuation of the photovoltaic module to be tested under the T98% temperature condition.

[0110] Step S609: Comprehensively evaluate the quality of the photovoltaic module to be tested based on the defect percentage and the power attenuation of the photovoltaic module to be tested.

[0111] Among them, the above steps S601 to S603 and step S605 can be tested by existing testing methods. Steps S604 and steps S606 to S609 can be implemented by the technical means provided in the above embodiments, and will not be elaborated here.

[0112] The second EL test result of the photovoltaic module to be tested under STC obtained in step S603, the first power test result of the photovoltaic module to be tested obtained in step S604, the first EL test result and the second power test result of the photovoltaic module to be tested obtained in step S606, calculating the defect percentage of the photovoltaic module to be tested in step S607, calculating the power attenuation of the photovoltaic module to be tested under the T98% temperature condition in step S608, and evaluating the quality of the photovoltaic module to be tested in step S609 can all be completed by a computer program, reducing manual operations and effectively improving the evaluation efficiency of the quality of the photovoltaic module to be tested.

[0113] Furthermore, an embodiment of the present invention provides an electronic device, which may include:

[0114] One or more processors;

[0115] A storage device for storing one or more programs,

[0116] When the one or more programs are executed by the one or more processors, the one or more processors implement the method for evaluating the quality of a photovoltaic module provided in any of the above embodiments.

[0117] Furthermore, an embodiment of the present invention provides a computer-readable medium, on which a computer program is stored, and when the program is executed by a processor, it implements the method for evaluating the quality of a photovoltaic module provided in any of the above embodiments.

[0118] In particular, according to the embodiments disclosed in the present invention, the processes described above with reference to the flowcharts (such as obtaining the second EL test result of the photovoltaic module to be tested under STC conditions in step S603, obtaining the first power test result of the photovoltaic module to be tested in step S604, obtaining the first EL test result and the second power test result of the photovoltaic module to be tested in step S606, calculating the defect percentage of the photovoltaic module to be tested in step S607, calculating the power attenuation of the photovoltaic module to be tested under the T98% temperature condition in step S608, and evaluating the quality of the photovoltaic module to be tested in step S609) can all be implemented as computer software programs, reducing manual operations and effectively improving the evaluation efficiency of the quality of the photovoltaic module to be tested. For example, the embodiments disclosed in the present invention include a computer program product that includes a computer program carried on a computer-readable medium, and the computer program contains program codes for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication part and / or installed from a removable medium. When the computer program is executed by a central processing unit (CPU), the above functions defined in the system of the present invention are executed.

[0119] It should be noted that the computer-readable medium shown in the present invention can be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of a computer-readable storage medium can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, a computer-readable storage medium can be any tangible medium that contains or stores a program, which can be used by or in conjunction with an instruction execution system, apparatus, or device. In the present invention, a computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, which carries computer-readable program code. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on a computer-readable medium can be transmitted using any appropriate medium, including but not limited to: wireless, wire, optical cable, RF, etc., or any suitable combination of the above.

[0120] The following uses a specific example of a main-gridless photovoltaic module (hereinafter referred to as a main-gridless module) for illustration.

[0121] Embodiment 1

[0122] For a main-gridless component, the conventional IEC61215 sequence test and the technical solution provided by the embodiment of the present invention are respectively used. The temperature threshold corresponding to the T98% temperature condition is set to 70°C. Under the T98% temperature condition, after power testing and aging sequence testing of the main-gridless component, EL testing and power testing of the main-gridless component under the T98% temperature condition are designed, and the defect percentage of the main-gridless component and the power attenuation under the T98% temperature condition are calculated respectively. As shown in Table 1 below, the power attenuation of the main-gridless component at 25°C in the conventional IEC61215 sequence test is 2%, and it meets the standard according to the conventional IEC61215 test results. However, based on the temperature threshold of 70°C corresponding to the T98% temperature condition for the main-gridless component, EL testing under the T98% temperature condition reveals that there is obvious EL blackening in the component, indicating obvious poor contact in the component, and this risk is not identified by the conventional IEC61215 test evaluation. Tested according to the method of the present invention, as shown in Table 1 below, the defect percentage of the component is 9%; the power attenuation of the component under the T98% temperature condition is 8%, both exceeding the standard range, and the component is determined to be failed. In addition, tested according to the method of the present invention, the temperature coefficient change value of the component is also given as 0.17%. Therefore, the embodiment of the present invention can identify the defects of non-welded components and provide data support for the evaluation of new technology components by designing to add EL testing and power testing of components under high temperature conditions before and after sequence aging.

[0123] Table 1

[0124] Test Items Test Conditions Test Results Test Conclusions Conventional IEC61215 Test: Module Power Decay PL - 25°C 25℃ 2％ Qualified Module Power Decay PL - T 98% (70°C) 70℃ 8％ Failed Module Temperature Coefficient Variation Value Δδ 25℃ / 70℃ 0.17％ / Ratio of New EL Defect Area of Module PEL 25℃ / 70℃ 9％ Failed

[0125] The introduction provided in the above steps is only used to help understand the structure, method and core idea of the present invention. For those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for evaluating the quality of a photovoltaic module, characterized in that: include: Step 1: before the sequential aging test, the temperature of the photovoltaic module to be tested is increased, and a power test is performed on the photovoltaic module to be tested in the temperature increase process to obtain a first power test result of the photovoltaic module to be tested; Step 2, after the sequence aging test, under the T98% temperature condition, perform an EL test and a power test on the photovoltaic module to be tested after the aging test to obtain a first EL test result and a second power test result of the photovoltaic module to be tested, wherein the T98% temperature condition means that under the measurement condition, the temperature of at least 98% of the temperature measurement position points among the multiple temperature measurement position points is not lower than the set temperature threshold; Step 3, calculating the defect percentage of the photovoltaic assembly to be tested by using the first EL test result and the second EL test result of the photovoltaic assembly to be tested under STC, wherein the second EL test result is obtained before the sequence aging test; Step 4: Calculate the power attenuation of the photovoltaic module to be tested under the temperature condition of T98% by using the first power test result and the second power test result; Step 5: Comprehensively evaluating the defect percentage and the power attenuation of the photovoltaic module to be tested to evaluate the quality of the photovoltaic module to be tested.

2. The method for evaluating the quality of photovoltaic modules according to claim 1, characterized in that: The power test of the photovoltaic module to be tested in the heating process in step 1 includes: Under the temperature condition of T98%, a power test is performed on the photovoltaic assembly to be tested, wherein the first power test result includes the first power of the photovoltaic assembly to be tested under the temperature condition of T98%.

3. The method for evaluating the quality of photovoltaic modules according to claim 1, characterized in that: The power test of the photovoltaic module to be tested in the heating process in step 1 includes: Performing a power test on the photovoltaic module to be tested at multiple heating temperatures, wherein the first power test result includes a third power of the photovoltaic module to be tested at each of the heating temperatures, wherein the multiple heating temperatures are based on 25° C.; Preferably, the photovoltaic module to be tested is heated from 25° C. to 105° C. according to a preset temperature increase gradient, and a power test is performed on the photovoltaic module to be tested under each of the preset temperature increase gradients; More preferably, the plurality of preset temperature rising gradients include: at least 98% of the temperature measurement positions are heated from 25°C to a first temperature range, the minimum value of the first temperature range is greater than 25°C and the maximum value of the first temperature range is not more than 70°C; at least 98% of the temperature measurement positions are heated from the first temperature range to a second temperature range, the minimum value of the second temperature range is greater than 70°C and the maximum value of the second temperature range is not more than 80°C; at least 98% of the temperature measurement positions are heated from the second temperature range to a third temperature range, the minimum value of the third temperature range is greater than 80°C and the maximum value of the third temperature range is not more than 90°C; at least 98% of the temperature measurement positions are heated from the third temperature range to a fourth temperature range, the minimum value of the fourth temperature range is greater than 90°C and the maximum value of the third temperature range is not more than 105°C.

4. The method for evaluating the quality of a photovoltaic module according to any one of claims 1 to 3, characterized in that: Step 3 includes: Step 31, using the second EL test result and the first EL test result, calculating the amount of new defects of the photovoltaic module to be tested under the temperature condition of T98%; Step 32: Calculate the defect percentage of the photovoltaic module to be tested by using the newly added defect amount of the photovoltaic module to be tested under the temperature condition of T98% and the basic data of the photovoltaic module to be tested, wherein the basic data includes the area of ​​the main surface of the photovoltaic module to be tested or the number of grids divided by the main surface of the photovoltaic module to be tested.

5. The method for evaluating the quality of photovoltaic modules according to claim 4, characterized in that: Step 31 includes: Step 311, gridding the photovoltaic module to be tested; Step 312, using an HSL color recognition method to respectively identify the number of first grids containing defects in the first EL test result and the number of second grids containing defects in the second EL test result; Step 313, using the first number of grids and the second number of grids, calculate the number of newly added defective grids; or, Step 311', using an HSL color recognition method to respectively identify the second defect area of ​​the second EL test result and the first defect area of ​​the first EL test result; Step 312 ′: using the first defect area and the second defect area, calculate the newly added defect area of ​​the photovoltaic module to be tested under the temperature condition of T98%.

6. The method for evaluating the quality of photovoltaic modules according to claim 5, characterized in that: The HSL color recognition method includes determining that an area with a brightness change value exceeding 5 is a defective area; Step 32 includes: In case that the newly added defect amount is the number of newly added defective grids, the defect percentage of the photovoltaic assembly to be tested is calculated using the number of newly added defective grids and the number of basic grids divided by the photovoltaic assembly to be tested; or, In case that the newly added defect amount is the newly added defect area, the defect percentage of the photovoltaic module to be tested is calculated using the newly added defect area of ​​the photovoltaic module to be tested under the temperature condition of T98% and the area of ​​the photovoltaic module to be tested.

7. The method for evaluating the quality of photovoltaic modules according to claim 2, characterized in that: Step 4 includes: The power attenuation is calculated according to the following first calculation formula using the first power of the photovoltaic module to be tested under the temperature condition of T98% and the second power of the photovoltaic module to be tested under the temperature condition of T98% in the second power test result; The first calculation formula: PL iv-T98％ ′=PL iv-25℃ +Δδ×(T98%-25℃) Among them, PL iv-T98％ ′ represents the power attenuation calculated by the first calculation formula; PL iv-25℃ Indicates the STC power attenuation of the photovoltaic module to be tested; Δδ indicates the temperature coefficient change value; T98% indicates the T98% temperature condition; Among them, PL iv-25℃ Calculated by the following second calculation formula: The second calculation formula: Among them, PL iv-25℃ represents the STC power attenuation of the photovoltaic module to be tested calculated by the second calculation formula; P 1iv-25℃ It represents the STC power of the PV module to be tested obtained before the sequential aging test; P 2iv-25℃ It represents the STC power of the PV module under test obtained after the sequential aging test.

8. The method for evaluating the quality of photovoltaic modules according to claim 3, characterized in that: Step 4 includes: Step 41, using each of the heating temperatures and the third power at each of the heating temperatures, calculating the temperature coefficient change value of the photovoltaic module to be tested from the STC to T98% temperature conditions; Step 42, using the STC power attenuation of the photovoltaic component to be tested, the temperature coefficient change value, the T98% temperature condition and the temperature corresponding to the STC, the power attenuation is calculated, wherein the STC power attenuation of the photovoltaic component to be tested is calculated based on the power of the photovoltaic component to be tested under the STC before the serial aging test and the power of the photovoltaic component to be tested under the STC after the serial aging test.

9. The method for evaluating the quality of photovoltaic modules according to claim 8, characterized in that: Step 41 includes: Step 411, using each of the heating temperatures and the third power at each of the heating temperatures, respectively calculate the first temperature coefficient of the photovoltaic assembly to be tested under STC and the second temperature coefficient of the photovoltaic assembly to be tested under T98% temperature condition; Step 412: Calculate a temperature coefficient change value using the first temperature coefficient and the second temperature coefficient.

10. The method for evaluating the quality of a photovoltaic module according to any one of claims 1 to 3 and 5 to 9, characterized in that: Step 5 includes: when the defect percentage is less than or equal to 5% and the power attenuation is less than or equal to 5%, determining that the photovoltaic module to be tested is of qualified quality; and / or, The evaluation method further comprises, before step 1: The photovoltaic modules to be tested are sequentially subjected to visual inspection, initial light stability test, power test and EL test under STC conditions.

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