Testing methods and devices for solar modules

Abstract

This application relates to a testing method and apparatus for solar modules, belonging to the field of photovoltaic technology. The testing method utilizes the synergistic effect of ultraviolet light and test current on the module under test (DUT) to induce and accelerate the diffusion of easily migratable metal elements, resulting in electrical performance and material degradation. By measuring the power degradation rate of the DUT, the correlation between the migration of easily migratable metal elements and the risk of power degradation is quantitatively analyzed. This provides experimental data support for material selection, process optimization, and product life prediction of the DUT, and is crucial for evaluating the reliability of modules using multiple metal materials. The testing method of this application fills the gap in existing testing systems where electrical participation is insufficient. It can simulate the working state of the DUT under years of outdoor aging, detecting potential long-term reliability problems of the DUT in a short time, greatly improving testing efficiency.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a method and apparatus for testing solar modules. Background Technology

[0002] The reliability of solar modules is a key factor determining their power generation efficiency and return on investment. To assess and ensure the durability of solar modules, the performance degradation and premature failure caused by environmental factors during outdoor service are becoming increasingly prominent. To evaluate module durability, the photovoltaic industry has established testing standards including ultraviolet aging (UV) testing, damp heat aging (DH) testing, thermal cycling (TC) testing, and wet freeze (HF) testing.

[0003] However, with the development of photovoltaic technology, the existing testing system still has limitations. Summary of the Invention

[0004] Therefore, it is necessary to provide a testing method and device for solar modules to address the problems in the existing technology.

[0005] In a first aspect, this application provides a method for testing solar modules, comprising the following steps:

[0006] The component under test is placed in an ultraviolet aging test environment and irradiated with ultraviolet light.

[0007] A constant detection current is continuously applied to the component under test. The detection current is used to drive the directional migration of easily migratable metal elements in the component under test. The detection current and ultraviolet light work together to accelerate the migration of the easily migratable metal elements in the component under test.

[0008] The power attenuation rate of the component under test is detected to assess the correlation between the migration of the easily migratable metal element and the power attenuation.

[0009] In one embodiment, the ratio of the current value of the detected current to the current value of the short-circuit current of the component under test is 1:(1-1.65).

[0010] In one embodiment, the detection current simulates the current direction of the component under test during power generation operation.

[0011] In one embodiment, the detection process is performed under 280nm-400nm ultraviolet light irradiation, and the cumulative ultraviolet irradiation during the detection process is 30kWh / m². 2 -220kWh / m 2 .

[0012] In one embodiment, the short-circuit current of the component under test is used as the detection current, and the cumulative ultraviolet irradiance during the detection process is 60 kWh / m². 2 -180kWh / m 2 .

[0013] In one embodiment, detecting the power attenuation rate of the component under test to assess the correlation between the migration of easily migratable metal elements and power attenuation includes:

[0014] Once the cumulative ultraviolet irradiation during the detection process reaches the target irradiation, the ultraviolet light irradiation to the component under test is stopped, and the detection current applied to the component under test is also stopped.

[0015] After the component under test is left to stand for a set period of time, the power attenuation rate of the component under test is detected.

[0016] Identify the target power attenuation threshold corresponding to the target irradiance, and compare the power attenuation rate of the component under test with the target power attenuation threshold. If the power attenuation rate of the component under test is greater than the target power attenuation threshold, it is determined that the migration of the easily migrated metal element caused the power attenuation of the component under test.

[0017] In one embodiment, the easily migratable metal element originates from the metal electrode of the component under test, and the metal electrode is made of a composite metal paste.

[0018] In one embodiment, detecting the power attenuation rate of the component under test to assess the correlation between the migration of easily migratable metal elements and power attenuation further includes:

[0019] Acquire an electroluminescence image of the component under test before detection, and extract the initial grayscale difference between the dark and bright areas in the image;

[0020] Acquire an electroluminescence image of the component under test after detection, and extract the grayscale difference between the dark and bright areas in the image after detection;

[0021] The grayscale difference after detection is compared with the initial grayscale difference. If the difference between the grayscale difference after detection and the initial grayscale difference is greater than a first preset value, it is determined that the power attenuation of the component under test is caused by the precipitation and oxidation of easily migratable metal elements in the metal electrode.

[0022] In one embodiment, after determining that the migration of the easily migratable metal element caused the power attenuation of the component under test, the following steps were also performed:

[0023] The metal electrodes of a solar module are made by replacing the original electrode material with a new electrode material; the proportion of the easily migratable metal element in the new electrode material is less than the proportion of the easily migratable metal element in the original electrode material.

[0024] In one embodiment, after determining that the migration of the easily migratable metal element caused the power attenuation of the component under test, the following steps were also performed:

[0025] An antioxidant layer is formed on the surface of the metal electrode, and / or the solar module is encapsulated with an antioxidant encapsulating film; the antioxidant encapsulating film contains at least one of an ultraviolet light cut-off agent or a light transfer agent.

[0026] Secondly, this application provides a testing apparatus for solar modules, used to perform the testing method for solar modules as described in the first aspect, the testing apparatus for solar modules comprising:

[0027] An ultraviolet testing chamber is provided, which includes a support plate and an ultraviolet irradiation module. The support plate is used to support the component under test, and the ultraviolet irradiation module is positioned facing the support plate to irradiate the component under test with ultraviolet light.

[0028] A current loading module is connected to the ultraviolet test chamber. The current loading module is used to continuously apply a constant detection current to the component under test. The detection current is used to drive the directional migration of easily migratable metal elements in the component under test. The detection current and ultraviolet light work together on the component under test to accelerate the migration of the easily migratable metal elements.

[0029] A detection module is used to detect the power attenuation rate of the component under test;

[0030] An analysis module is connected to the detection module for data analysis. The analysis module evaluates the correlation between the migration of easily migratable metal elements and power attenuation based on the power attenuation rate of the component under test.

[0031] The solar module testing method and apparatus of this application utilize the synergistic effect of ultraviolet light and test current on the module under test to induce and accelerate the diffusion of easily migratable metal elements, resulting in electrical performance and material degradation. By measuring the power degradation rate of the module under test, the correlation between the migration of easily migratable metal elements and the risk of power degradation can be quantitatively analyzed. This provides experimental data support for material selection, process optimization, and product life prediction of the module under test, and is crucial for evaluating the reliability of modules using multiple metal materials. The testing method of this application fills the gap in the existing testing system where electrical participation is insufficient. It can simulate the working state of the module under test after many years of outdoor aging, detect potential long-term reliability problems of the module under test in a short time, and greatly improve the testing efficiency. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart of a method for detecting solar modules provided in one embodiment;

[0034] Figure 2 This is a flowchart for evaluating the correlation between the migration of easily migratable metal elements and power attenuation, provided in another embodiment.

[0035] Figure 3 This is a schematic diagram of the structure of a solar module detection device provided in another embodiment.

[0036] Figure label:

[0037] 201. Ultraviolet testing chamber; 204. Current loading module; 205. Detection module; 206. Analysis module; 1. Power cable; 2. Protective cover; 4. Ultraviolet irradiation module; 3. Status light; 5. Door hinge; 6. Interaction unit; 7. Observation window; 8. First sealed protective door; 9. Chamber; 10. Horizontal adjustment feet; 11. Support plate; 12. Component under test; 13. Door handle; 14. Constant current cable; 15. Power cabinet; 16. Second sealed protective door; 17. Controller. Detailed Implementation

[0038] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate preferred embodiments of the application. However, this application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0040] The reliability testing system for solar modules mainly simulates the impact of the natural environment on the modules. However, with the development of solar modules, especially the mixed application of various metal materials (such as copper, silver, tin-based solders and new low-silver or silver-free pastes) in cell grids, interconnect solder strips and busbars, the existing testing system has revealed certain limitations.

[0041] Currently, most existing testing systems apply environmental stresses individually or sequentially. For example, UV aging tests are only conducted under "no-load" conditions with no bias voltage and no current. This is significantly different from the state in which solar modules are constantly exposed to sunlight, heated, and simultaneously generating and outputting current when working outdoors. In fact, it cannot simulate the real working state of solar modules, making it impossible to effectively assess and quantify the electrochemical reliability risks inside the modules under the combined effects of UV irradiation, heat, and operating current.

[0042] In particular, when solar modules are simultaneously under operating bias, a strong electric field is generated inside the module. This field drives the directional migration of ions generated by ultraviolet light, leading to ion enrichment at the contact interfaces of different metals. This results in severe electrochemical corrosion and metal migration. This can cause increased contact resistance of cell grid lines and solder joints, or even open circuits, manifesting as nonlinear power decay of the module and ultimately causing early failure. Existing testing systems lack effective detection and risk assessment capabilities for potential failure mechanisms induced by current diffusion, especially those involving multi-metal hybrid systems under the synergistic effects of ultraviolet light and bias.

[0043] According to an exemplary embodiment, this embodiment provides a method for testing solar modules, including the following steps:

[0044] Step S101: Place the component under test in the ultraviolet aging test environment and irradiate the component under test with ultraviolet light.

[0045] In this embodiment, the component under test (DUT) is placed in an ultraviolet (UV) testing chamber, and the testing conditions of the UV testing chamber are adjusted to simulate UV testing conditions, irradiating the DUT with UV light. Specifically, the temperature of the UV testing chamber is adjusted to 50°C-70°C to simulate the outdoor operating temperature of the DUT; for example, the temperature can be set to 50°C, 55°C, 60°C, 65°C, or 70°C. Preferably, the temperature can be set to 55°C-65°C.

[0046] By simulating and enhancing the ultraviolet radiation from outdoor sunlight using an ultraviolet test chamber, the component under test is irradiated with ultraviolet light. This degrades the polymer encapsulation material of the component under test, causing its molecular chains to break and generating and releasing mobile active ions. At the same time, it reduces the volume resistivity of the encapsulation material, creating conditions for the subsequent accelerated migration of easily migrating metal elements.

[0047] In this embodiment, the UVB content in the ultraviolet light irradiating the component under test accounts for 3%-5% of the total ultraviolet irradiance, and the irradiation uniformity is <10%. A UVB content of 3%-5% can more quickly damage the passivation and insulation properties of the component under test's encapsulation, accelerate the yellowing, powdering, and decomposition of the encapsulation material, and generate a large number of mobile active ions in a short period of time, providing reactants for subsequent electrochemical corrosion.

[0048] Step S102: A constant detection current is continuously applied to the component under test. The detection current is used to drive the directional migration of easily migratable metal elements in the component under test. The detection current and ultraviolet light work together to accelerate the migration of easily migratable metal elements in the component under test.

[0049] In this embodiment, while step S101 is being performed, a constant detection current can be applied to the component under test by an external power source to form an electric field inside the component under test. The electric field drives the directional migration of easily migrated metal elements in the component under test. The easily migrated metal elements will accumulate at the interface (such as the surface of the metal electrode) and undergo electrochemical reactions, such as oxidation.

[0050] In step S101, the mobile ions generated by ultraviolet irradiation in the encapsulation material also undergo directional migration. After these ions migrate to the metallized areas of the solar cell (such as grid lines, solder ribbons, etc.), they accumulate at the interfaces of different metals. These ions weaken the protective capability of the insulating material in the metallized areas and also make easily migratable metal elements more susceptible to oxidation at the interfaces, contributing to the aging of the module under test. This more accurately reproduces the failure process caused by the outdoor aging of the module under test.

[0051] Step S103: Detect the power attenuation rate of the component under test to assess the correlation between the migration of easily migratable metal elements and power attenuation.

[0052] In this embodiment, after the component under test has undergone ultraviolet irradiation and current detection for a preset duration, or after the accumulated ultraviolet irradiation reaches a set value, the ultraviolet light irradiation to the component under test is stopped, and the detection current is also stopped.

[0053] In this embodiment, after the component under test is left to stand for a period of time, the maximum output power P of the component under test after the test is measured. max 1. The component under test (P) before reaching its maximum output power during testing. max The system compares and calculates the power attenuation rate ΔP% of the component under test (SUT). Based on this ΔP%, the impact of easily migratable metal element migration on the SUT's reliability is analyzed and quantified, providing experimental data support and improvement directions for material selection, process optimization, and product life prediction. In this embodiment, a power meter can be used to measure the maximum output power of the SUT.

[0054] The solar module testing method described above utilizes the synergistic effect of ultraviolet light and test current on the module under test (DUT) to induce and accelerate the diffusion of easily migratable metal elements, resulting in electrical performance and material degradation. By measuring the power degradation rate of the DUT, the correlation between the migration of easily migratable metal elements and the risk of power degradation can be quantitatively analyzed. This provides experimental data support for material selection, process optimization, and product life prediction of the DUT, and is crucial for evaluating the reliability of modules using multiple metal materials. The testing method of this application fills the gap in the existing testing system where electrical participation is insufficient. It can simulate the working state of the DUT under years of outdoor aging and detect potential long-term reliability problems of the DUT in a short time, greatly improving the testing efficiency.

[0055] In some embodiments, the ratio of the detected current value to the short-circuit current value of the component under test is 1:(1-1.65). For example, if the short-circuit current of the component under test is 15.6A, the range of the detected current value is 15.6A-25.35A.

[0056] Furthermore, the ratio of the detected current value to the short-circuit current value of the component under test can be 1:(1-1.55); further, the ratio of the detected current value to the short-circuit current value of the component under test can be 1:(1-1.4); further, the ratio of the detected current value to the short-circuit current value of the component under test can be 1:(1-1.25).

[0057] It should be noted that the short-circuit current Isc refers to the maximum current that a solar module can generate when it is in a short-circuit state, that is, when the load resistance is zero. The magnitude of the short-circuit current directly affects the output power of the solar module.

[0058] The output current of the solar module when working outdoors is between 0 and the short-circuit current (Isc). In this embodiment, the ratio of the detected current value to the short-circuit current value of the module under test is set to 1:(1-1.65), which can quickly simulate the working state of the solar cell and has high reference value for testing the reliability of the solar module in the actual power station.

[0059] If the detection current is too small (e.g., much smaller than the cell's maximum power point current Impp), it cannot generate a strong electric field within the module to drive ion migration and induce electrochemical reactions, resulting in inaccurate test results. If the current is too high (e.g., much larger than the short-circuit current), it may introduce problems such as hot spot effects, making it impossible to effectively assess and quantify the electrochemical reliability risks within the module under the combined influence of UV irradiation, heat, and operating current.

[0060] In this embodiment, by applying a detection current close to the actual operating current to the solar module, an electric field sufficient to drive the migration of easily migratable metal elements can be established within the module. This is crucial for detecting the migration and oxidation of easily migratable metal elements (such as copper and aluminum) under the influence of potential difference.

[0061] For example, the ratio of the detected current value to the short-circuit current value of the component under test can be 1:1, 1:125, 1:15, 1:175, 1:1.2, 1:1.225, 1:1.25, 1:1.275, 1:1.3, 1:1.325, 1:1.35, 1:1.375, 1:1.4, 1:425, 1:45, 1:475, 1:1.5, 1:1.525, 1:1.55, 1:1575, 1:1.6, 1:1.625, or 1:1.65.

[0062] In some embodiments, the detected current simulates the current direction of the component under test during power generation operation.

[0063] It is understandable that when a solar module generates electricity outdoors, the current flows from the N-type region of the cells inside the module to the P-type region (positive terminal). In other words, in the external circuit, the current flows out from the positive terminal of the module and into the negative terminal.

[0064] In this embodiment, when applying a detection current using an external power source, the positive terminal of the external power source is connected to the positive terminal of the component under test (SUT), and the negative terminal of the external power source is connected to the negative terminal of the SUT. This allows for the simulation of the actual operating state of the solar panel to be maximized.

[0065] In some embodiments, the detection process is performed under ultraviolet light irradiation of 280nm-400nm. For example, the wavelength of the ultraviolet light can be 280nm, 290nm, 300nm, 310nm, 320nm, 330nm, 340nm, 350nm, 360nm, 370nm, 380nm, 390nm or 400nm.

[0066] In some embodiments, the cumulative ultraviolet irradiation during the detection process is 30 kWh / m². 2 -220kWh / m 2 That is, in this embodiment, the condition for termination of detection is the cumulative ultraviolet irradiation.

[0067] In this embodiment, the solar modules under test can be divided into multiple groups for testing with different cumulative ultraviolet irradiance levels, based on their operating area and expected operating duration. This allows for comparison of multiple test results, further analysis of the correlation between the migration of easily migrating metal elements and module reliability, and a more accurate estimation of the lifespan of the modules under test based on the test results with different cumulative ultraviolet irradiance levels.

[0068] In one example, the cumulative UV irradiation during the detection process was 30 kWh / m². 2 -40kWh / m 2 It is used to simulate the ultraviolet dose of the component under test when it is operated outdoors in areas with strong ultraviolet light (such as high altitudes) for 3-6 months.

[0069] In one example, the cumulative UV irradiation during the detection process was 60 kWh / m². 2 -120kWh / m 2 It is used to simulate the ultraviolet dose of the component under test when it is operating outdoors for 1-2 years.

[0070] In one example, the cumulative ultraviolet irradiation during the detection process was 1800 kWh / m². 2 -220kWh / m 2 It is used for the ultimate life test of the component under test.

[0071] In other embodiments, the cumulative ultraviolet irradiance during the detection process can be set according to the type of solar cells in the solar module.

[0072] In some embodiments, the short-circuit current of the component under test is used as the detection current, that is, a detection current with the same value as the short-circuit current is applied to the component under test, and the cumulative ultraviolet irradiation during the detection process is 60 kWh / m². 2 -180kWh / m 2 For example, if the short-circuit current of the component under test is 15.6A, then the magnitude of the detection current is 15.6A.

[0073] In some embodiments, step S103 detects the power attenuation rate of the component under test to assess the correlation between the migration of easily migratable metal elements and power attenuation, including:

[0074] Step S1031: After the cumulative ultraviolet irradiation during the detection process reaches the target irradiation, stop irradiating the component under test with ultraviolet light and stop applying the detection current to the component under test.

[0075] In this embodiment, after the cumulative ultraviolet irradiation reaches the target irradiation, the ultraviolet light source is turned off, the ultraviolet light irradiation to the component under test is stopped, the external power supply is turned off, the detection current applied to the component under test is stopped, and the temperature of the ultraviolet test chamber is reduced to room temperature, or the component under test is transferred to a room temperature environment and left to stand.

[0076] Step S1032: After the component under test has been left to stand for a set time, the power attenuation rate of the component under test is detected.

[0077] In this embodiment, the component under test is placed in an environment with a temperature of (23±5)℃ and a relative humidity of ≤75%, and the component under test is left to stand for a set time, for example, 2-4 hours.

[0078] It is understandable that after undergoing testing with high temperatures, strong light, and detection circuitry, the component under test (DUT) may exhibit temporary and recoverable degradation defects. Allowing the DUT to rest can eliminate these temporary and recoverable degradation effects on the test results, ensuring that the measured power attenuation rate is due to permanent and irreversible material degradation, thereby improving the accuracy of the test results.

[0079] After allowing the device under test to stand for a set time, the maximum output power P of the device under test is measured using a power meter. max 1. The component under test (P) before reaching its maximum output power during testing. max Compare with 0 and calculate the power attenuation rate ΔP of the component under test.

[0080] Step S1033: Identify the target power attenuation threshold corresponding to the target irradiance, and compare the power attenuation rate of the component under test with the target power attenuation threshold. If the power attenuation rate of the component under test is greater than the target power attenuation threshold, it is determined that the power attenuation of the component under test is caused by the migration of easily migratable metal elements.

[0081] In this embodiment, the power decay rate of the component under test (SUT) is compared with the target power decay threshold corresponding to the target irradiance. If the power decay rate of the SUT is greater than the target power decay threshold, it is determined that the failure of the component is mainly caused by the migration of easily migratable metal elements (and the oxidation they induce). If the power decay rate of the SUT is less than or equal to the threshold, it indicates that its power decay is within an acceptable range, and the migration of easily migratable metal elements is within an acceptable range for the reliability of the SUT.

[0082] It should be noted that the target power degradation threshold is not a fixed value. The target power degradation threshold is determined by conducting this test on a large number of known high-performance, technologically mature solar modules, and statistically analyzing the parameters taken when the tested module reaches the target irradiance (e.g., 120 kWh / m²). 2 The power attenuation rate after testing is used as the average power attenuation rate of a large number of components under test as the target power attenuation threshold corresponding to the target irradiance.

[0083] Table 1 provides the target power attenuation thresholds for different target irradiance levels when a detection current of 15.6A is applied to the module under test with the short-circuit current Isc.

[0084] Table 1. Correspondence between target irradiance and target power attenuation threshold

[0085]

[0086] Alternatively, in some other embodiments, when performing this test on the component under test, a reference component can be used as a control group. The reference component and the component under test are solar modules manufactured from the same batch. An ultraviolet aging test is performed on the reference component. The only difference between the ultraviolet aging test and this test is that no detection current is applied to the reference component; all other test conditions are the same as in this test.

[0087] After the test, the power attenuation rate of the component under test (DUT) and the power attenuation rate of the reference component were measured. The increase in power attenuation of the DUT relative to the reference component is the attenuation induced by current diffusion. The increase in power attenuation of the DUT relative to the reference component can be directly used for product quality testing (such as batch sampling inspection), new material system testing, and process optimization testing.

[0088] In some embodiments, the easily migratable metal element originates from the metal electrode of the component under test, and the metal electrode is made of a composite metal paste.

[0089] It is understandable that the development of metallization in solar modules uses non-silver materials to replace some or all of the silver materials in the production of metal grid electrodes. The main alternative materials used, such as copper and aluminum, are prone to migration and oxidation in humid, hot, biased, and ion-containing environments, forming a high-resistivity metal oxide layer on the surface of the metal electrode. This leads to a sharp increase in the resistance of the metal electrode or even an open circuit, thereby causing power attenuation.

[0090] The detection method of this embodiment is applied to solar modules with metal electrodes made of composite metal paste, such as silver-copper paste, silver-coated copper paste, or silver-aluminum paste, etc., and can assess whether the migration of copper and / or aluminum elements affects the reliability of the solar module. This embodiment does not constitute a limitation on easily migratable metal elements.

[0091] In some embodiments, step S103 detects the power attenuation rate of the component under test to assess the correlation between the migration of easily migratable metal elements and power attenuation, such as... Figure 2 As shown, it also includes:

[0092] Step S103-a: Obtain the electroluminescence image of the component under test before detection, and extract the initial grayscale difference between the dark and bright areas in the image.

[0093] In this embodiment, before conducting accelerated aging tests, an electroluminescence imager is used to perform electroluminescence (EL) imaging on the component under test, acquiring its electroluminescence image. The terminal divides the pre-detection electroluminescence image into multiple uniform initial regions through an image processing program, identifies and extracts the darkest and brightest regions, and calculates the grayscale difference between the average grayscale value of the darkest region and the average grayscale value of the brightest region as the initial grayscale difference value.

[0094] Step S103-b: Obtain the electroluminescence image of the component under test after detection, and extract the grayscale difference between the dark and bright areas in the image after detection.

[0095] It is understandable that if the metal electrode oxidizes, carriers in that region will not be effectively injected or will undergo non-radiative recombination, thus suppressing electroluminescence. Therefore, after accelerated aging testing of the device under test, these regions where carrier injection or recombination is hindered will appear as darker areas in the electroluminescence image. Specific morphologies of the dark areas include, but are not limited to: dark lines distributed along the edge or direction of the metal electrode, irregularly shaped black spots, or dark areas that highly overlap with the metal electrode grid pattern.

[0096] The terminal analyzes the electroluminescence image after detection using the same image processing algorithm and region segmentation rules as the pre-detection electroluminescence image. Based on the image grayscale histogram or a preset grayscale threshold, the terminal automatically identifies abnormal dark areas in the post-detection electroluminescence image. Simultaneously, it identifies normal bright areas in unaffected regions. The terminal calculates the difference between the average grayscale value of the abnormal dark areas and the average grayscale value of the normal bright areas as the post-detection grayscale difference value.

[0097] Step S103-c: Compare the grayscale difference after detection with the initial grayscale difference. If the difference between the grayscale difference after detection and the initial grayscale difference is greater than the first preset value, it is determined that the power attenuation of the component under test is caused by the precipitation and oxidation of easily migratable metal elements in the metal electrode.

[0098] In this embodiment, the terminal calculates the difference between the grayscale difference after detection and the initial grayscale difference, and compares it with a first preset value. The first preset value is obtained after statistical analysis and calibration of test data from a large number of known high-performance solar modules and known modules with metal migration failures.

[0099] If the difference between the grayscale difference and the initial grayscale difference is greater than a first preset value, it is judged as abnormal. After testing, the internal current distribution and carrier recombination of the component under test conform to the failure mode caused by metal migration. The terminal determines that the power decay of the component under test is mainly due to the precipitation, migration and subsequent oxidation of easily migratable metal elements (such as copper) in the metal electrode. The terminal determines and outputs this determination result. In this embodiment, the first preset value is 50%.

[0100] Furthermore, in this embodiment, the tolerance for the precipitation of easily migrating metal elements can be determined according to the type of the component under test, thereby determining the magnitude of the first preset value. For example, for solar modules using back-contact cells or solar modules using ultra-fine grid lines, the tolerance of the metal electrodes for the precipitation of easily migrating metal elements is small, so the first preset value can be set smaller, such as 30%; for components with larger tolerances, the first preset value can be set larger, such as 65%.

[0101] In some embodiments, the degree of damage to the component can also be assessed based on the difference between the detected grayscale difference and the initial grayscale difference. For example, if the difference between the detected grayscale difference and the initial grayscale difference is less than 50%, the component under test is assessed as not having failed; if the difference between the detected grayscale difference and the initial grayscale difference is 50%-65%, the component under test is assessed as having a first-level failure; if the difference between the detected grayscale difference and the initial grayscale difference is greater than 65%, the component under test is assessed as having a second-level failure.

[0102] In some embodiments, after determining in step S103 that the migration of easily migratable metal elements causes power attenuation of the component under test, the following steps are also performed:

[0103] Step S104: Replace the original electrode material with a new electrode material to make the metal electrode of the solar module; the proportion of easily migratable metal elements in the new electrode material is less than the proportion of easily migratable metal elements in the original electrode material.

[0104] In this embodiment, after the detection result indicates that the power attenuation of the tested module is caused by the migration of easily migratable metal elements, the manufacturing process of the solar module is improved based on the determination result to optimize the performance of the solar module and make it meet the testing requirements. In this embodiment, the failure probability can be reduced by decreasing the mass or volume percentage of copper in the new electrode material forming the metal electrode, thereby reducing the absolute number of easily migratable sources.

[0105] For example, new electrode materials include silver-coated copper core-shell structure materials, which include a silver-coated copper core structure and a silver shell layer covering the silver-coated copper core structure.

[0106] The silver-clad copper core-shell structure material includes a silver-clad copper core structure and a silver layer structure. The silver-clad copper core structure consists of silver-clad copper particles, while the silver shell layer consists only of silver particles. The dense silver shell layer completely isolates the silver-clad copper particles from the external environment, fundamentally preventing direct contact between copper and the external environment, thereby avoiding copper oxidation.

[0107] In some embodiments, the silver-coated copper core structure includes copper particles and a silver particle layer covering the copper particles. The mass ratio of silver in the silver-coated copper particles is 30%-40%. The silver particle layer completely covers the copper particle layer, and the porosity of the silver particle layer is less than 0.5%. The porosity of the silver shell layer is less than 0.3%.

[0108] In some embodiments, the silver shell layer is formed by at least three electroless plating processes.

[0109] In this embodiment, after executing step S104, the detection method of this embodiment can be used to iteratively verify the reproduced solar modules to complete the closed-loop process of reliability analysis, attribution and location, scheme improvement and iterative verification of solar cells. Based on the detection results, this embodiment can directly and quickly guide the research and development and production of new products and new materials, which is conducive to shortening the research and development cycle and production cost of new materials (such as silver-coated copper paste).

[0110] It should be noted that if, after testing, obvious oxidation and discoloration appear on the surface of the metal electrode of the component under test, or if the abnormal dark area in the electroluminescence image of the component under test after testing is manifested as a dark line or dark spot that is obviously distributed along the electrode, it can be directly determined that the power attenuation of the component under test is caused by the precipitation and oxidation of easily migratable metal elements in the metal electrode.

[0111] In some embodiments, after determining in step S103 that the migration of easily migratable metal elements causes power attenuation of the component under test, the following steps are also performed:

[0112] Step S105: Form an antioxidant layer on the surface of the metal electrode.

[0113] It is understandable that although the combined effect of ultraviolet irradiation and detection current can promote the diffusion of easily migratable metal elements and is the main influencing factor of metal oxidation, the decrease in the passivation effect of the passivation layer destroys the protective barrier, causing easily migratable metal elements that have migrated to the surface of the metal electrode to come into contact with water and oxygen, which is another influencing factor of metal oxidation.

[0114] In this embodiment, after the detection results indicate that the migration of easily migratable metal elements has caused the power attenuation of the component under test, passivation can be strengthened based on the detection results to prevent copper elements from directly contacting the external environment, thereby avoiding copper oxidation.

[0115] In this embodiment, after performing step S104, step S105 can be performed to form an antioxidant layer on the surface of the metal electrode. The antioxidant layer may include aluminum oxide (Al2O3) or silicon nitride (SiN). x Inorganic films made of materials such as titanium dioxide (TiO2) can be used to prevent water vapor and oxygen from penetrating into the metal electrode, thereby protecting the metal (especially copper) from corrosion.

[0116] And / or, after determining in step S103 that the migration of easily migratable metal elements caused the power attenuation of the component under test, the following steps were also performed:

[0117] Step S106: Encapsulate the solar module with an antioxidant encapsulating film; the antioxidant encapsulating film contains at least one of an ultraviolet light cut-off agent or a light transfer agent.

[0118] The antioxidant encapsulating film can be made of ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), or co-extruded composite film thereof, and at least one of ultraviolet light blocking agent and / or light transfer agent is uniformly dispersed in the antioxidant encapsulating film.

[0119] Ultraviolet (UV) light blocking agents absorb or reflect UV light, preventing it from penetrating the encapsulating film and reaching the metal electrode, thereby reducing the induction of easily migrating metal elements through oxidation. UV light blocking agents can be selected from organic UV absorbers, such as benzotriazoles or benzophenones.

[0120] Light conversion agents can absorb some ultraviolet light and emit lower-energy, longer-wavelength visible or near-infrared light through a down-conversion mechanism. Converting ultraviolet light into visible or near-infrared light, which is beneficial for module power generation, helps increase the module's short-circuit current (Isc) and power output. Inorganic rare-earth-doped fluorescent materials can be selected as light conversion agents.

[0121] According to an exemplary embodiment, this embodiment provides a solar module testing apparatus for performing the solar module testing method of the above embodiment, such as... Figure 3 As shown, the testing device for solar modules includes an ultraviolet testing chamber 201, a current loading module 204, a detection module 205, and an analysis module 206.

[0122] like Figure 3 As shown, the ultraviolet test chamber 201 includes a chamber 9, inside which a support plate 11 and an ultraviolet irradiation module 4 are provided. The support plate 11 is used to support the component under test 12. The support plate 11 is made of an insulating material that is resistant to ultraviolet radiation and high temperature (such as anodized aluminum or Teflon coating) to electrically isolate the component under test 12 from the chamber 9.

[0123] like Figure 3As shown, the ultraviolet irradiation module 4 is disposed on the top of the housing 9 and faces the support plate 11. The ultraviolet irradiation module 4 is used to irradiate the component under test 12 with ultraviolet light. The ultraviolet irradiation module 4 may include multiple ultraviolet lamp groups, each group comprising multiple ultraviolet lamps with set wavelengths, used to emit ultraviolet light with wavelengths in the range of 280nm to 400nm. The ultraviolet lamps are covered by protective covers 2 to protect the lamps. The ultraviolet irradiation module 4 may also include an irradiation sensor (not shown in the figure), which is used to monitor and provide feedback on the ultraviolet irradiance irradiated onto the surface of the component under test 12 in real time.

[0124] The chamber 9 is also equipped with a temperature control module (not shown in the figure). The temperature control module may include a heater and a temperature sensor. The temperature control module is used to adjust the temperature inside the chamber 9.

[0125] like Figure 3 As shown, the enclosure 9 includes a first sealed protective door 8 and a second sealed protective door 16. Both the first sealed protective door 8 and the second sealed protective door 16 are equipped with door hinges 5 and door handles 13. During the testing process, the first sealed protective door 8 and the second sealed protective door 16 are closed to form a sealed testing environment inside the enclosure 9, which isolates the external environment and prevents ultraviolet light leakage.

[0126] like Figure 3 As shown, the chamber 9 is also equipped with an observation window 7, which is embedded in the first sealed protective door 8. The observation window 7 is transparent, allowing observation of the state of the sample to be tested inside the chamber 9 during the testing process without interrupting the test or exposing the operator to ultraviolet radiation. Figure 3 As shown, the bottom of the housing 9 is also equipped with leveling feet 10 to adjust the level and stability of the entire device.

[0127] like Figure 3 As shown, a status light 3 is also provided on the top of the enclosure 9. The status light 3 displays the corresponding color (such as green, yellow, red) according to the operating status of the enclosure 9, so as to intuitively display the current operating status of the equipment (such as normal operation, standby, alarm / fault, etc.).

[0128] like Figure 3As shown, the current loading module 204 is connected to the ultraviolet test chamber 201. The current loading module 204 continuously applies a constant detection current to the component under test 12, which drives the directional migration of easily migratable metal elements in the component under test 12. The detection current and ultraviolet light work together to accelerate the migration of easily migratable metal elements in the component under test 12. The current loading module 204 includes a power cable 1, a constant current cable 14, and a power cabinet 15. The power cabinet 15 integrates a high-precision programmable DC power supply with constant current (CC) and constant voltage (CV) modes. The power cabinet 15 is introduced into the chamber 9 through the interface on the side wall of the chamber 9 via the constant current cable 14 to apply the detection current to the component under test 12 during testing. The power cabinet 15 provides power input to the entire device through the power cable 1.

[0129] like Figure 3 As shown, the detection module 205 is used to detect the power attenuation rate of the component under test 12. The detection module 205 includes at least a power detector, which is located outside the ultraviolet testing chamber 201. The power detector is used to detect the power attenuation value of the component under test 12 before and after testing. The detection module 205 may also include an electroluminescence imager: used to capture electroluminescence images of the component under test 12 before and after testing, visually displaying defects caused by metal migration, oxidation, etc., in the component under test 12.

[0130] like Figure 3 As shown, the analysis module 206 is connected to the detection module 205. The analysis module 206 evaluates the correlation between the migration of easily migratable metal elements and power attenuation based on the power attenuation rate of the component under test 12.

[0131] like Figure 3 As shown, the analysis module 206 is data-connected to the detection module 205, and is also controllably connected to the ultraviolet irradiation module 4 and the current loading module 204. The analysis module 206 can serve as a terminal. The analysis module 206 includes a controller 17 and an interaction unit 6. The interaction unit 6 is used to set test parameters (temperature, ultraviolet light intensity, detection current, test time), start / stop the test, and display all operating parameters and curves in real time. After setting the test parameters, the interaction unit 6 sends instructions to the controller 17. The controller 17 controls the ultraviolet irradiation module 4 and the current loading module 204 to execute the instructions issued by the interaction unit 6, precisely controlling the irradiation parameters of the ultraviolet irradiation module 4 and the parameters of the current loading module 204, etc.

[0132] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0133] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method of detecting a solar module, characterized by, The method comprises the following steps: placing a to-be-tested component in an ultraviolet aging test environment, irradiating the to-be-tested component with ultraviolet light, the to-be-tested component having a metal electrode; continuously applying a constant detection current to the to-be-tested component, the ultraviolet light being used to degrade encapsulating materials and generate movable ions, the detection current forming an electric field inside the component to drive directional migration of easily-migrating metal elements in the to-be-tested component, the detection current and the ultraviolet light being used to induce and accelerate electrochemical migration of the easily-migrating metal elements; detecting a power attenuation rate of the to-be-tested component to evaluate the correlation between migration of the easily-migrating metal elements and power attenuation; wherein the irradiation of the to-be-tested component with ultraviolet light is stopped and the application of the detection current to the to-be-tested component is stopped after the cumulative ultraviolet irradiation amount of the detection process reaches a target irradiation amount; after the to-be-tested component is left to stand for a set period of time, detecting a power attenuation rate of the to-be-tested component; identifying a target power attenuation threshold corresponding to the target irradiation amount, and comparing the power attenuation rate of the to-be-tested component with the target power attenuation threshold, if the power attenuation rate of the to-be-tested component is greater than the target power attenuation threshold, it is determined that the migration of the easily-migrating metal elements causes power attenuation of the to-be-tested component; obtaining electroluminescence images of the to-be-tested component before and after detection, and extracting initial gray scale difference values and detection gray scale difference values of dark areas and bright areas in the images respectively; if the difference between the detection gray scale difference value and the initial gray scale difference value is greater than a first preset value, it is determined that the power attenuation of the to-be-tested component is caused by the precipitation and oxidation of the easily-migrating metal elements in the metal electrode.

2. The method of claim 1, wherein The ratio of the current value of the detection current to the current value of the short-circuit current of the to-be-tested component is 1: (1-1.65).

3. The method of claim 1, wherein The detection current simulates the current direction of the to-be-tested component in a power generation operating state.

4. The method of claim 1, wherein The detection process is carried out under 280nm-400nm ultraviolet light irradiation, and the cumulative ultraviolet radiation of the detection process is 30kWh / m 2 -220kWh / m 2 .

5. The method of claim 4, wherein The short-circuit current of the component to be tested is taken as the detection current, and the cumulative ultraviolet radiation of the detection process is 60 kWh / m 2 -180 kWh / m 2 .

6. The method of claim 1, wherein The easily-migrating metal elements are derived from the metal electrode of the to-be-tested component, and the metal electrode is made of a composite metal paste.

7. The method of claim 6, wherein the step of detecting the solar module comprises the steps of: detecting a voltage of the solar module; and determining whether the voltage is within a predetermined range. After it is determined that the migration of the easily-migrating metal elements causes power attenuation of the to-be-tested component, the following steps are further performed: a metal electrode of a solar component is made of a new electrode material to replace an original electrode material, and the proportion of the easily-migrating metal elements in the new electrode material is less than the proportion of the easily-migrating metal elements in the original electrode material.

8. The method of claim 6, wherein the step of detecting the solar module comprises the steps of: detecting a voltage of the solar module; and determining whether the voltage is within a predetermined range. After it is determined that the migration of the easily-migrating metal elements causes power attenuation of the to-be-tested component, the following steps are further performed: an oxidation-resistant layer is formed on the surface of the metal electrode, and / or an oxidation-resistant encapsulating adhesive film is used to encapsulate the solar component, and at least one of an ultraviolet light cut-off agent or a light conversion agent is added to the oxidation-resistant encapsulating adhesive film.

9. A solar module inspection apparatus for performing the solar module inspection method according to any one of claims 1 to 8, characterized by, The detection device of the solar component comprises: an ultraviolet test box, the ultraviolet test box being provided with a bearing plate and an ultraviolet irradiation module, the bearing plate being used to bear a to-be-tested component, and the ultraviolet irradiation module being arranged towards the bearing plate to irradiate the to-be-tested component with ultraviolet light; A current loading module is connected with the ultraviolet test box, and is used for continuously applying a constant detection current to the component to be tested, the detection current is used for driving the easy-to-migrate metal elements in the component to be tested to migrate directionally, and the detection current cooperates with the ultraviolet light to act on the component to be tested, and accelerates the migration of the easy-to-migrate metal elements. A detection module is used for detecting the power attenuation rate of the component to be tested. An analysis module is connected with the detection module in data, and the analysis module evaluates the correlation between the migration of the easy-to-migrate metal elements and the power attenuation according to the power attenuation rate of the component to be tested.

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