Method for testing photovoltaic modules

Abstract

The embodiment of the present application relates to the field of photovoltaic, and provides a kind of photovoltaic module testing method.The grid line material of the photovoltaic module to be measured includes multiple metals, and the method comprises: the performance test is carried out to the photovoltaic module to be measured, and first test result is obtained;In the test environment with temperature range of 73-92 ℃ and relative humidity range of 70-95%RH, predetermined current 800-2000 hours is continuously input to the photovoltaic module to be measured, to carry out aging test to the photovoltaic module to be measured, predetermined current is greater than or equal to the maximum power point current of the photovoltaic module to be measured, and less than or equal to the short-circuit current of the photovoltaic module to be measured;The performance test is carried out to the photovoltaic module to be measured after aging test, and second test result is obtained;According to first test result and second test result, the performance of grid line material is determined.The present application at least solves the problem that the aging test of existing photovoltaic module cannot detect the reliability of grid line material.

Description

Technical Field

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

[0002] A photovoltaic (PV) cell is a photoelectric conversion device that uses semiconductor materials to absorb photons and generate an electric current. It converts solar radiation energy into electrical energy, thus providing humanity with a clean and renewable energy source. In recent years, with the increasing severity of the global energy crisis and environmental pollution, photovoltaic power generation technology has developed rapidly and been widely applied. However, the lifespan and stability of PV modules are key factors affecting their long-term reliability.

[0003] Currently, the photovoltaic industry commonly uses aging tests to evaluate the performance and durability of photovoltaic modules, simulating the aging effects and risk quantification of solar cell modules under environmental humidity and high / low temperature shocks. However, existing aging test methods typically only focus on the overall performance of photovoltaic modules, neglecting the performance evaluation of the grid line materials. Summary of the Invention

[0004] This application provides a testing method for photovoltaic modules, which at least solves the problem that existing aging tests for photovoltaic modules cannot detect the reliability of grid line materials.

[0005] According to some embodiments of this application, one aspect of this application provides a testing method for a photovoltaic module. The grid wire material of the photovoltaic module under test includes various metals. The method includes: performing a performance test on the photovoltaic module under test to obtain a first test result; continuously applying a predetermined current to the photovoltaic module under test for 800 to 2000 hours in a test environment with a temperature range of 73 to 92°C and a relative humidity range of 70 to 95% RH to perform an aging test on the photovoltaic module under test, wherein the predetermined current is greater than or equal to the maximum power point current of the photovoltaic module under test and less than or equal to the short-circuit current of the photovoltaic module under test; performing the performance test on the photovoltaic module under test after the aging test to obtain a second test result; and determining the performance of the grid wire material based on the first test result and the second test result.

[0006] In some embodiments, in a test environment with a temperature range of 73–92°C and a relative humidity range of 70–95%RH, a predetermined current is continuously supplied to the photovoltaic module under test for 800–2000 hours to perform an aging test on the photovoltaic module under test. This includes: electrically connecting the photovoltaic module under test to a constant current source and placing the photovoltaic module under test in an environmental chamber; setting the operating temperature of the environmental chamber to a target temperature value and the operating humidity to a target relative humidity value, and turning on the environmental chamber; when the temperature in the environmental chamber is stable within a first range corresponding to the target temperature value and the relative humidity is stable within a second range corresponding to the target relative humidity value, setting the output current of the constant current source to the predetermined current and turning on the switch of the constant current source to continuously supply the short-circuit current to the photovoltaic module under test through the constant current source, and controlling the supply time to a target duration value, wherein the target temperature value and the first range are both within the temperature range, the target relative humidity value and the second range are both within the relative humidity range, and the target duration value is within the range of 800–2000 hours.

[0007] In some embodiments, when the target temperature is 90°C and the target relative humidity is 90%RH, the first range is 88–92°C, the second range is 85–95%RH, the predetermined current is the short-circuit current, and the target duration is 800 hours.

[0008] In some embodiments, when the target temperature is 85°C and the target relative humidity is 85%RH, the first range is 83-87°C, the second range is 80-90%RH, the predetermined current is the short-circuit current, and the target duration is 1000 hours.

[0009] In some embodiments, when the target temperature is 80°C and the target relative humidity is 80%RH, the first range is 78–82°C, the second range is 75–85%RH, the predetermined current is the maximum power point current, and the target duration is 1500 hours.

[0010] In some embodiments, when the target temperature is 75°C and the target relative humidity is 75%RH, the first range is 73-77°C, the second range is 70-80%RH, the predetermined current is the maximum power point current, and the target duration is 2000 hours.

[0011] In some embodiments, before connecting the photovoltaic module under test to a constant current source and placing the photovoltaic module under test in an environmental chamber, the testing method for the photovoltaic module further includes: acquiring the target temperature value and the target relative humidity value; determining the target duration value and the value of the predetermined current based on the target temperature value, the target relative humidity value, and a predetermined relationship, wherein the predetermined relationship characterizes the correspondence between temperature, relative humidity, duration, and current, and in the predetermined relationship, the duration corresponding to a first temperature and a first relative humidity is greater than the duration corresponding to a second temperature and a second relative humidity, the current corresponding to the first temperature and the first relative humidity is less than or equal to the current corresponding to the second temperature and the second relative humidity, the first temperature is less than the second temperature, and the first relative humidity is less than the second relative humidity.

[0012] In some embodiments, when the performance of the grid line material is determined to be unqualified, the testing method for the photovoltaic module further includes: acquiring internal metal ion distribution data of the unqualified photovoltaic module before and after the aging test; determining the diffusion path of metal ions based on the internal metal ion distribution data; and adjusting at least one of the following based on the diffusion path: the composition ratio of the metal in the grid line material and the type of metal in the grid line material.

[0013] In some embodiments, the performance test includes a power test, and the performance of the gate wire material is determined based on the first test result and the second test result, including: determining a power attenuation value based on the power test value in the first test result and the functional test value in the second test result; and determining whether the performance of the gate wire material is qualified based at least on the power attenuation value.

[0014] In some embodiments, the performance test further includes an electroluminescence test, which determines whether the performance of the grid line material is qualified based at least on the power decay value. This includes: comparing the electroluminescence test image in the first test result with the electroluminescence test image in the second test result to determine the electroluminescence test result, wherein the electroluminescence test result includes parameter difference data of the photovoltaic module under test before and after the aging test, and newly added defect data of the photovoltaic module under test after the aging test; if the power decay value is less than 5% and the electroluminescence test result meets the electroluminescence test standard, the performance of the grid line material is determined to be qualified; if the power decay value is greater than or equal to 5% and the electroluminescence test result does not meet the electroluminescence test standard, the performance of the grid line material is determined to be unqualified.

[0015] The technical solution provided in this application embodiment has at least the following advantages: In the photovoltaic module testing method, before conducting an aging test on the photovoltaic module under test whose grid line material includes multiple metals, a performance test is first performed to obtain a first test result; then, an aging test is conducted on the photovoltaic module under test under test conditions of a test temperature of 73-92°C, a relative humidity of 70-95%RH, and a predetermined current continuously applied for 800-2000 hours, wherein the predetermined current is not less than the maximum power point current of the photovoltaic module under test and not greater than the short-circuit current; then, a performance test is performed on the photovoltaic module under test after the aging test to obtain a second test result; finally, based on the two test results, the performance of the grid line material in the photovoltaic module under test is determined. This application provides a continuous current of no less than the maximum power point current and no greater than the short-circuit current to the photovoltaic module under test under high temperature and high humidity conditions to accelerate the migration speed of metallic inorganic matter in the grid line material (also known as battery paste) of the photovoltaic module. This can simulate the electrical performance degradation of the photovoltaic module under humid and hot conditions and current diffusion-induced conditions. By comparing the performance test results before and after aging, the changes in the performance of the grid line material are quantified, and an effective evaluation of the grid line material performance is achieved. This provides a quantitative method for the reliability risk of new grid line materials and solves the problem that the aging test of existing photovoltaic modules cannot detect the reliability of the grid line material. Attached Figure Description

[0016] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the drawings in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional art, the drawings used in the embodiments 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.

[0017] Figure 1 This is a schematic flowchart of a testing method for a photovoltaic module provided in one embodiment of this application;

[0018] Figure 2 This is a schematic diagram of the structure of a photovoltaic module testing device provided in one embodiment of this application.

[0019] The above figures include the following reference numerals:

[0020] 1. Sealed protective door; 2. Status observation window; 3. Door handle; 4. Connecting hinge; 5. Horizontal adjustment bracket; 6. Inner door seal; 7. Portable casters; 8. Photovoltaic module under test; 9. Equipment control console; 10. Constant current source control box; 11. Connecting cables; 12. Display control panel; 13. Cold shrink tubing for wire ends; 14. Module protective frame; 15. Enclosure seal; 16. Cooling water piping. Detailed Implementation

[0021] As described in the background section, in the prior art, aging tests of photovoltaic modules cannot detect the reliability of grid line materials. To solve the above problems, embodiments of this application provide a testing method for photovoltaic modules.

[0022] The grid wire material of the photovoltaic module under test includes various metals. The testing method for the photovoltaic module includes: performing a performance test on the photovoltaic module under test to obtain a first test result; continuously applying a predetermined current to the photovoltaic module under test for 800 to 2000 hours in a test environment with a temperature range of 73 to 92°C and a relative humidity range of 70 to 95% RH to perform an aging test on the photovoltaic module under test, wherein the predetermined current is greater than or equal to the maximum power point current of the photovoltaic module under test and less than or equal to the short-circuit current of the photovoltaic module under test; performing the performance test on the photovoltaic module under test after the aging test to obtain a second test result; and determining the performance of the grid wire material based on the first test result and the second test result.

[0023] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0024] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0026] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0027] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0028] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the terms in the embodiments of this application can be understood according to the specific circumstances.

[0029] In the accompanying drawings corresponding to the embodiments of this application, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0030] In the description of the embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and other components may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or it can have another component present in between. Moreover, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located in between.

[0031] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "part" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0032] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0033] This embodiment provides a testing method for photovoltaic modules that run on a mobile terminal, computer terminal, or similar computing device. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Also, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0034] Figure 1 This is a flowchart of a testing method for a photovoltaic module according to an embodiment of this application. The grid line material of the photovoltaic module under test includes various metals, such as... Figure 1 As shown, the method includes the following steps:

[0035] Step S201: Perform performance testing on the photovoltaic module under test to obtain the first test result;

[0036] In some embodiments, the performance test includes testing the electrical performance parameters of the photovoltaic module, and the test items include, but are not limited to, power testing and electroluminescence testing.

[0037] Step S202: In a test environment with a temperature range of 73 to 92°C and a relative humidity range of 70 to 95%RH, a predetermined current is continuously applied to the photovoltaic module under test for 800 to 2000 hours to perform an aging test on the photovoltaic module under test. The predetermined current is greater than or equal to the maximum power point current of the photovoltaic module under test and less than or equal to the short-circuit current of the photovoltaic module under test.

[0038] Specifically, the maximum power point current (Imp) is the current when the photovoltaic module's output power reaches its maximum value. The short-circuit current (Isc) is the maximum current generated by the photovoltaic module when its output terminal is short-circuited, i.e., the voltage between the two terminals is zero. For photovoltaic modules, both the maximum power point current (Imp) and the short-circuit current (Isc) are fixed values.

[0039] Step S203: Perform the performance test on the photovoltaic module under test after the aging test to obtain the second test result;

[0040] In some embodiments, the performance test items for the photovoltaic module under test are the same before and after the aging test.

[0041] Step S204: Determine the performance of the gate wire material based on the first test result and the second test result.

[0042] In the above embodiment, before conducting aging tests on photovoltaic modules whose grid line materials include various metals, performance tests are first performed to obtain a first test result. Then, an aging test is conducted on the photovoltaic modules under test under test conditions of a test temperature of 73-92°C, a relative humidity of 70-95%RH, and a predetermined current continuously applied for 800-2000 hours. The predetermined current meets the requirement of being no less than the maximum power point current of the photovoltaic modules under test and no greater than the short-circuit current. The performance of the photovoltaic modules under test after the aging test is then tested to obtain a second test result. Finally, based on the two test results, the performance of the grid line material in the photovoltaic modules under test is determined. This application provides a continuous current of no less than the maximum power point current and no greater than the short-circuit current to the photovoltaic module under test under high temperature and high humidity conditions to accelerate the migration speed of metallic inorganic matter in the grid line material (also known as battery paste) of the photovoltaic module. This can simulate the electrical performance degradation of the photovoltaic module under humid and hot conditions and current diffusion-induced conditions. By comparing the performance test results before and after aging, the changes in the performance of the grid line material are quantified, and an effective evaluation of the grid line material performance is achieved. This provides a quantitative method for the reliability risk of new grid line materials and solves the problem that the aging test of existing photovoltaic modules cannot detect the reliability of the grid line material.

[0043] The inventors discovered that existing reliability testing schemes for photovoltaic modules have relatively lenient testing conditions. The current supplied to the photovoltaic module is only used to monitor its current continuity and ensure no open circuit occurs during the test, without contributing to accelerated aging such as current diffusion induction. In contrast, the method described in this application continuously provides a predetermined current to the photovoltaic module under test in a high-temperature and high-humidity environment to simulate the electrical performance degradation of the photovoltaic module under current diffusion-induced aging conditions of damp heat, thus achieving the goal of quantifying the risk of the gate material.

[0044] In specific applications, the grid line material of the photovoltaic module under test can be silver-clad copper or other mixed metal materials.

[0045] In addition to the performance test, the method of this application can also perform appearance inspection on the photovoltaic module under test before and after the aging test to obtain two appearance inspection results, which can help determine the performance of the photovoltaic module under test.

[0046] In one exemplary embodiment, in a test environment with a temperature range of 73–92°C and a relative humidity range of 70–95%RH, a predetermined current is continuously supplied to the photovoltaic module under test for 800–2000 hours to perform an aging test on the photovoltaic module under test. This includes: electrically connecting the photovoltaic module under test to a constant current source and placing the photovoltaic module under test in an environmental chamber; setting the operating temperature of the environmental chamber to a target temperature value and the operating humidity to a target relative humidity value, and turning on the environmental chamber; when the temperature in the environmental chamber is stable within a first range corresponding to the target temperature value and the relative humidity is stable within a second range corresponding to the target relative humidity value, setting the output current of the constant current source to the predetermined current and turning on the switch of the constant current source, so as to continuously supply the short-circuit current to the photovoltaic module under test through the constant current source, and controlling the supply duration to a target duration value, wherein the target temperature value and the first range are both within the temperature range, the target relative humidity value and the second range are both within the relative humidity range, and the target duration value is within the range of 800–2000 hours.

[0047] In the aforementioned embodiment, the photovoltaic module under test is placed in an environmental chamber. By precisely controlling the temperature and humidity within the chamber, the environmental conditions for the aging test are ensured to be accurate and controllable. A constant current source continuously provides a stable, predetermined current to the photovoltaic module under test, simulating its actual operating state under extreme climatic conditions. By controlling the three key variables of temperature, humidity, and current, the reliability risks of novel grid line materials under extreme environmental conditions can be accurately quantified in a short time, revealing potential electrochemical reactions and metal diffusion problems. This helps to identify and resolve issues that may affect the long-term performance and lifespan of the module at an early stage, thereby improving product quality and user satisfaction. Furthermore, by using current-driven diffusion steps to accelerate the diffusion process of metal ions (such as silver and copper) within the cell, the time required to test the long-term reliability of the photovoltaic module can be significantly shortened, which is beneficial for improving testing efficiency and R&D cycle.

[0048] According to other embodiments of this application, when the target temperature is 90°C and the target relative humidity is 90%RH, the first range is 88–92°C, the second range is 85–95%RH, the predetermined current is the short-circuit current, and the target duration is 800 hours. In this embodiment, applying a short-circuit current under the set maximum temperature and humidity conditions to perform an aging test on the photovoltaic module under test can accelerate the chemical reaction of the grid material (such as the oxidation or corrosion process of metals) to the maximum extent, and simulate extreme electrical fault conditions. This dual-stress test helps to discover the performance limits of materials under extreme environments.

[0049] In some embodiments, with the target temperature value of 85°C and the target relative humidity value of 85%RH, the first range is 83–87°C, the second range is 80–90%RH, the predetermined current value is the short-circuit current, and the target duration is 1000 hours. In this embodiment, applying a short-circuit current to the photovoltaic module under test at temperatures and humidity slightly below the maximum conditions allows for a more detailed evaluation of the performance of the grid wire material under relatively common but still harsh environmental conditions. It also allows for a more precise determination of the changing trend of the grid wire material under long-term exposure to high temperature, high humidity, and extreme electrical fault environments, which is beneficial for predicting the reliability of the grid wire material performance.

[0050] In other embodiments, when the target temperature is 80°C and the target relative humidity is 80%RH, the first range is 78–82°C, the second range is 75–85%RH, the predetermined current is the maximum power point current, and the target duration is 1500 hours. In this embodiment, applying the maximum power point current to the photovoltaic module under test in a temperature and humidity environment of 80°C and 80%RH allows for a more accurate evaluation of the performance of the grid wire material in a relatively mild high-temperature and high-humidity environment.

[0051] In some embodiments, when the target temperature is 75°C and the target relative humidity is 75%RH, the first range is 73–77°C, the second range is 70–80%RH, the predetermined current is the maximum power point current, and the target duration is 2000 hours. In this embodiment, applying the maximum power point current to the photovoltaic module under test in a mild high-temperature and high-humidity environment for a long-term aging test can evaluate the performance stability of the grid line material under relatively mild but long-term environmental stress.

[0052] Specifically, the first range is determined based on the target temperature value and the temperature tolerance of the environmental chamber, while the second range is determined based on the target relative humidity value and the humidity tolerance of the environmental chamber.

[0053] According to some alternative embodiments of this application, before connecting the photovoltaic module under test to a constant current source and placing the photovoltaic module under test in an environmental chamber, the testing method for the photovoltaic module further includes: acquiring the target temperature value and the target relative humidity value; determining the target duration value and the value of the predetermined current based on the target temperature value, the target relative humidity value, and a predetermined relationship, wherein the predetermined relationship characterizes the correspondence between temperature, relative humidity, duration of operation, and current flow, and in the predetermined relationship, the duration of operation corresponding to a first temperature and a first relative humidity is greater than the duration of operation corresponding to a second temperature and a second relative humidity, the current flow corresponding to the first temperature and the first relative humidity is less than or equal to the current flow corresponding to the second temperature and the second relative humidity, the first temperature is less than the second temperature, and the first relative humidity is less than the second relative humidity.

[0054] In the embodiments described above, by using a predefined relationship between temperature, relative humidity, operating time, and current, the performance of different gate wire materials under different environmental conditions can be systematically evaluated, thereby achieving an effective evaluation of the performance of gate wire materials and further realizing the goal of providing a reliability quantification method for novel gate wire materials.

[0055] In some embodiments of this application, when the performance of the grid wire material is determined to be substandard, the testing method for the photovoltaic module further includes: acquiring internal metal ion distribution data of the substandard photovoltaic module before and after the aging test; determining the diffusion path of metal ions based on the internal metal ion distribution data; and adjusting at least one of the following based on the diffusion path: the proportion of the metal component in the grid wire material and the type of metal in the grid wire material. When the grid wire material is found to be substandard, this solution can understand the diffusion path of metal ions within the material by analyzing the internal metal ion distribution data, thereby helping researchers accurately identify the cause of the material performance degradation—whether it is due to improper selection of metal components or an unreasonable proportion of components. Based on these analysis results, the proportion or type of metal component in the grid wire material can be adjusted in a targeted manner, thereby optimizing the chemical stability and mechanical strength of the material and improving the overall performance and service life of the photovoltaic module.

[0056] For example, the specific process of determining the diffusion path of metal ions based on the internal metal ion distribution data may include: using a precision cutting tool such as a diamond wire saw to cut the EL performance abnormal area containing the battery cell, EVA / POE film, and glass / backsheet interface into small samples; embedding the small samples with a material such as epoxy resin to maintain the structural integrity of the small samples during subsequent slicing; slicing the embedded small samples using ion beam cutting technology (such as FIB-focused ion beam) or polishing technology to prepare a cross-sectional sample perpendicular to the surface of the battery cell, the cross-sectional sample including the area from the front side (grid lines, anti-reflection layer) to the back side (back field, back electrode) of the battery cell, and the cross-sectional sample may also include the grid line edges and PN junction area; performing depth profiling and surface distribution analysis of the cross-sectional sample using time-of-flight secondary ion mass spectrometry (TOF-SIMS) or dynamic secondary ion mass spectrometry (D-SIMS), and determining the metal ion diffusion path according to the distribution concentration of metal ions from high to low.

[0057] The gate wire material includes base metals (such as copper) and noble metals (such as silver). For example, adjusting the proportion of the metals in the gate wire material according to the diffusion path may include the following steps: comparing the ion concentrations at locations on the gate wire, between gate wires, and at the PN junction, identifying the point of maximum concentration of metal ions in the depth direction, i.e., the location of the ion concentration peak; if the location of the ion concentration peak is located at the PN junction, adjusting the ratio of base metals and noble metals in the gate wire material to mitigate the bulk recombination caused by metal ion diffusion.

[0058] In some embodiments, the performance test includes a power test, and determining the performance of the gate line material according to the first test result and the second test result includes: determining a power attenuation value according to the power test value in the first test result and the function test value in the second test result; determining whether the performance of the gate line material is qualified at least according to the power attenuation value. By comparing the power test values before and after aging, the power attenuation value can be determined, and then the performance stability of the gate line material can be evaluated.

[0059] For example, determining whether the performance of the gate line material is qualified at least according to the power attenuation value may include: if the power attenuation value is less than 5%, determining that the performance of the gate line material is qualified; if the power attenuation value is greater than or equal to 5%, determining that the performance of the gate line material is unqualified.

[0060] In some other embodiments, the performance test further includes an electroluminescence test, and determining whether the performance of the gate line material is qualified at least according to the power attenuation value includes: comparing the electroluminescence test image in the first test result with the electroluminescence test image in the second test result to determine an electroluminescence test result, where the electroluminescence test result includes parameter difference data of the photovoltaic module to be tested before and after the aging test and new defect data of the photovoltaic module to be tested after the aging test; if the power attenuation value is less than 5% and the electroluminescence test result meets the electroluminescence test standard, determining that the performance of the gate line material is qualified; if the power attenuation value is greater than or equal to 5% and the electroluminescence test result does not meet the electroluminescence test standard, determining that the performance of the gate line material is unqualified. By comparing the electroluminescence test images before and after aging, the degree of influence of the aging test on the performance of the photovoltaic module, such as the power attenuation situation and new defect data, can be determined; the combination of the electroluminescence test and the power test can comprehensively evaluate the performance stability of the gate line material, ensure that a relatively accurate performance of the photovoltaic module under extreme environmental conditions is obtained, and provide an intuitive defect analysis basis for material selection and design optimization of the photovoltaic module.

[0061] Specifically, the power test is one of the key methods for evaluating the performance of photovoltaic modules, and it directly reflects the electrical efficiency of the photovoltaic modules. The electroluminescence test is a non-destructive detection method, which can visually display the defect distribution inside the photovoltaic module, such as the fracture or corrosion of the gate line material.

[0062] In some embodiments, before performing the performance test on the photovoltaic module under test after the aging test to obtain the second test result, the testing method for the photovoltaic module further includes: stopping the power supply to the photovoltaic module under test when the predetermined current transmission time reaches the target time value; and placing the photovoltaic module under test with the power supply stopped in an environment with a temperature of 18-28°C and a relative humidity of less than or equal to 75%RH for 2-4 hours. In this scheme, placing the photovoltaic module under test in an environment with a temperature of 18-28°C and a relative humidity of less than or equal to 75%RH after the aging test ensures that the internal temperature and humidity of the photovoltaic module return to the normal range before subsequent performance testing, avoiding the influence of high temperature and high humidity on the test results; by allowing it to stand after the test, the interference of environmental factors on the test results can be effectively reduced, ensuring the scientificity and reliability of the test results; this processing method can ensure the accuracy of performance testing and provide reliable data support for the material selection and design optimization of photovoltaic modules.

[0063] In some embodiments, multiple photovoltaic modules under test are included in the same batch, and these modules are placed at intervals in the environmental chamber. The testing method for the photovoltaic modules further includes determining that the performance of multiple photovoltaic modules under test in the same batch is qualified if the proportion of photovoltaic modules with qualified grid line material is greater than or equal to 95%. By evaluating the grid line material performance of multiple photovoltaic modules under test in the same batch, the mass production quality of photovoltaic modules and the performance consistency of photovoltaic modules in mass production can be ensured, providing a batch evaluation basis for the material selection and design optimization of photovoltaic module grid lines.

[0064] In other exemplary embodiments, the predetermined current may further include a plurality of test current values ​​that increase sequentially, wherein the smallest test current is equal to the maximum power point current and the largest test current value is equal to the short-circuit current. In a test environment with a temperature range of 73–92°C and a relative humidity range of 70–95%RH, a predetermined current is continuously supplied to the photovoltaic module under test for 800–2000 hours to perform an aging test on the photovoltaic module under test, including: in the test environment with a temperature range of 73–92°C and a relative humidity range of 70–95%RH, a plurality of currents corresponding to the successively increasing test current values ​​are sequentially supplied to the photovoltaic module under test, such that the continuous power supply time of the photovoltaic module under test reaches 800–2000 hours.

[0065] To enable those skilled in the art to better understand the technical solution of this application, the implementation process of the photovoltaic module testing method of this application will be described in detail below with reference to specific embodiments.

[0066] This embodiment relates to a specific testing device for photovoltaic modules, including an environmental chamber and a constant current source control box 10, such as... Figure 2 As shown, the environmental enclosure includes a sealed protective door 1, a status observation window 2, a door handle 3, a connecting hinge 4, a leveling bracket 5, an inner door seal 6, portable casters 7, an equipment control console 9, a display control panel 12, wire end cold shrink tubing 13, a component protective frame 14, an enclosure seal 15, and cooling water pipes 16. A constant current source control box 10 is electrically connected to the environmental enclosure via a connecting cable 11. Figure 2 The image also shows a partially enlarged view of the cold-shrink tubing 13 at the lead wire tip of the environmental chamber. The testing method for the photovoltaic module may specifically include the following steps:

[0067] Step S1: Use a power tester to test the power and EL (Electroluminescence) of the photovoltaic module 8 under test, and continue to step S2;

[0068] Step S2: Check if the cooling water pipe 16 of the environmental chamber is blocked. If it is confirmed that the cooling water pipe 16 is not blocked, continue to step S3.

[0069] Step S3: Open the sealed protective door 1 of the environmental chamber, fix the photovoltaic module 8 to be tested on the module protective frame 14 of the environmental chamber, and continue to step S4;

[0070] Step S4: Pass the connecting cable 11 of the constant current source control box 10 through the test hole on the side wall of the environmental chamber and connect it with the component connecting cable using a male and female connector, and put on the wire head cold shrink tubing 13, then continue to step S5.

[0071] Step S5: Close the sealed protective door 1 of the environmental chamber, turn on the power of the environmental chamber, set the temperature of the environmental chamber to 85℃ and the relative humidity to 85%RH, and continue to step S6;

[0072] Step S6: After the environmental chamber has been running for 2 hours, determine whether the temperature and humidity inside the environmental chamber have reached the set temperature and humidity according to the temperature and humidity display control screen 12 of the environmental chamber. After the set temperature and humidity have been reached and the temperature and humidity display on the control screen 12 is stable, turn on the constant current source control box 10 switch, adjust the DC current to the short circuit current Isc value marked on the nameplate of the photovoltaic module 8 under test, and continue to step S7.

[0073] Step S7: After 1000 hours of testing, the test will automatically stop. Place the photovoltaic module 8 under test in an environment with a temperature of (23±5)℃ and a relative humidity of ≤75% for 2-4 hours, and then continue to step S8.

[0074] Step S8: Use a power tester to test the power of the photovoltaic module 8 under test and perform EL testing. Calculate the power degradation value before and after aging. The judgment criterion is that the degradation value is <5%.

[0075] As can be seen from the above description, the embodiments described in this application achieve the following technical effects:

[0076] In the testing method for photovoltaic modules, before conducting aging tests on photovoltaic modules whose grid line materials include various metals, performance tests are first performed to obtain the first test result. Then, an aging test is conducted on the photovoltaic modules under test under test conditions of a test temperature of 73-92℃, a relative humidity of 70-95%RH, and a predetermined current continuously applied for 800-2000 hours. The predetermined current is not less than the maximum power point current of the photovoltaic modules under test and not greater than the short-circuit current. The photovoltaic modules under test after the aging test are then subjected to performance tests to obtain the second test result. Finally, based on the two test results, the performance of the grid line material in the photovoltaic modules under test is determined. This application provides a continuous current of no less than the maximum power point current and no greater than the short-circuit current to the photovoltaic module under test under high temperature and high humidity conditions to accelerate the migration speed of metallic inorganic matter in the grid line material (also known as battery paste) of the photovoltaic module. This can simulate the electrical performance degradation of the photovoltaic module under humid and hot conditions and current diffusion-induced conditions. By comparing the performance test results before and after aging, the changes in the performance of the grid line material are quantified, and an effective evaluation of the grid line material performance is achieved. This provides a quantitative method for the reliability risk of new grid line materials and solves the problem that the aging test of existing photovoltaic modules cannot detect the reliability of the grid line material.

[0077] Those skilled in the art will understand that the various embodiments described are specific examples of implementing this application, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A testing method for photovoltaic modules, characterized in that, The grid wire material of the photovoltaic module under test includes various metals, and the method includes: The photovoltaic module under test was subjected to performance testing to obtain the first test result; In a test environment with a temperature range of 73~92℃ and a relative humidity range of 70~95%RH, a predetermined current is continuously applied to the photovoltaic module under test for 800~2000 hours to conduct an aging test on the photovoltaic module under test. The predetermined current is greater than or equal to the maximum power point current of the photovoltaic module under test and less than or equal to the short circuit current of the photovoltaic module under test. The performance test is performed on the photovoltaic module under test after the aging test to obtain the second test result; The performance of the gate wire material is determined based on the first test results and the second test results; In a test environment with a temperature range of 73~92℃ and a relative humidity range of 70~95%RH, a predetermined current is continuously supplied to the photovoltaic module under test for 800~2000 hours to perform an aging test on the photovoltaic module under test. The test includes: electrically connecting the photovoltaic module under test to a constant current source and placing the photovoltaic module under test in an environmental chamber; setting the operating temperature of the environmental chamber to a target temperature value and the operating humidity to a target relative humidity value, and turning on the environmental chamber; when the temperature in the environmental chamber is stable within a first range corresponding to the target temperature value and the relative humidity is stable within a second range corresponding to the target relative humidity value, setting the output current of the constant current source to the predetermined current and turning on the switch of the constant current source, so as to continuously supply the short-circuit current to the photovoltaic module under test through the constant current source, and controlling the supply time to a target duration value, wherein the target temperature value and the first range are both within the temperature range, the target relative humidity value and the second range are both within the relative humidity range, and the target duration value is within the range of 800~2000 hours. Before connecting the photovoltaic module under test to a constant current source and placing it in an environmental chamber, the testing method for the photovoltaic module further includes: acquiring the target temperature value and the target relative humidity value; determining the target duration value and the value of the predetermined current based on the target temperature value, the target relative humidity value, and a predetermined relationship, wherein the predetermined relationship characterizes the correspondence between temperature, relative humidity, duration, and current, and in the predetermined relationship, the duration corresponding to the first temperature and the first relative humidity is greater than the duration corresponding to the second temperature and the second relative humidity, the current corresponding to the first temperature and the first relative humidity is less than or equal to the current corresponding to the second temperature and the second relative humidity, the first temperature is less than the second temperature, and the first relative humidity is less than the second relative humidity; The performance test includes a power test. Based on the first test result and the second test result, the performance of the gate wire material is determined, including: determining a power attenuation value based on the power test value in the first test result and the functional test value in the second test result; and determining whether the performance of the gate wire material is qualified based at least on the power attenuation value. The performance test also includes an electroluminescence test, which determines whether the performance of the grid line material is qualified based at least on the power decay value. This includes: comparing the electroluminescence test images in the first test result and the electroluminescence test images in the second test result to determine the electroluminescence test result. The electroluminescence test result includes parameter difference data of the photovoltaic module under test before and after the aging test, as well as new defect data of the photovoltaic module under test after the aging test. If the power decay value is less than 5% and the electroluminescence test result meets the electroluminescence test standard, the performance of the grid line material is determined to be qualified. If the power decay value is greater than or equal to 5% and the electroluminescence test result does not meet the electroluminescence test standard, the performance of the grid line material is determined to be unqualified. Before performing the performance test on the photovoltaic module under test after the aging test and obtaining the second test result, the test method for the photovoltaic module further includes: stopping the power supply to the photovoltaic module under test when the transmission time of the predetermined current reaches the target time value; and placing the photovoltaic module under test with the power supply stopped in an environment with a temperature of 18~28℃ and a relative humidity of less than or equal to 75%RH for 2~4 hours.

2. The testing method for photovoltaic modules according to claim 1, characterized in that, With the target temperature value being 90℃ and the target relative humidity value being 90%RH, the first range is 88~92℃, the second range is 85~95%RH, the predetermined current value is the short-circuit current, and the target duration value is 800 hours.

3. The testing method for photovoltaic modules according to claim 1, characterized in that, With the target temperature value being 85℃ and the target relative humidity value being 85%RH, the first range is 83~87℃, the second range is 80~90%RH, the predetermined current value is the short-circuit current, and the target duration value is 1000 hours.

4. The testing method for photovoltaic modules according to claim 1, characterized in that, With the target temperature value being 80℃ and the target relative humidity value being 80%RH, the first range is 78~82℃, the second range is 75~85%RH, the predetermined current value is the maximum power point current, and the target duration value is 1500 hours.

5. The testing method for photovoltaic modules according to claim 1, characterized in that, With the target temperature value of 75°C and the target relative humidity value of 75%RH, the first range is 73~77°C, the second range is 70~80%RH, the predetermined current value is the maximum power point current, and the target duration value is 2000 hours.

6. The testing method for photovoltaic modules according to claim 1, characterized in that, If the performance of the grid wire material is determined to be substandard, the testing method for the photovoltaic module further includes: Obtain internal metal ion distribution data of the photovoltaic module under test that fails to meet performance standards before and after the aging test; Based on the internal metal ion distribution data, the diffusion path of the metal ions is determined; Based on the diffusion path, at least one of the following is adjusted: the composition ratio of the metal in the gate wire material, and the type of the metal in the gate wire material.

Images