Method and device for testing reliability of photovoltaic junction box

Abstract

The invention discloses a method and a device for testing the reliability of a photovoltaic junction box, and belongs to the field of photovoltaic technologies. The photovoltaic junction box reliability test method comprises the steps that electrical performance test is carried out on a test sample to obtain a first test result, and the test sample comprises a plurality of photovoltaic junction boxes which are connected in sequence; immersing the test sample in a test liquid in a test environment, and carrying out an aging test on the test sample; performing an electrical performance test on the test sample after the aging test to obtain a second test result; and determining the reliability of the photovoltaic junction box according to the first test result and the second test result. According to the invention, the long-term working reliability of the photovoltaic junction box in the water immersion environment can be evaluated, and the evaluation accuracy is improved.

Description

Technical Field

[0001] The present application belongs to the field of photovoltaic technology, and in particular relates to a method and device for testing the reliability of a photovoltaic junction box. Background Art

[0002] In recent years, the photovoltaic industry has developed rapidly. As the main body of solar power generation, the safety and reliability of photovoltaic modules are becoming increasingly important. The photovoltaic junction box is a key part of the photovoltaic module, responsible for transmitting the current generated by the photovoltaic module cells. Photovoltaic modules and photovoltaic junction boxes are installed outdoors, so the photovoltaic junction box needs to be tested for reliability to ensure its long-term normal operation.

[0003] Most PV junction boxes are designed for ground-based power stations and rooftop distributed PV. Currently, the reliability test of PV junction boxes only conducts strict aging tests for conventional working environments. For working environments such as offshore PV, there is a risk of long-term immersion in water for PV junction boxes, and there is currently no corresponding reliability test method. Summary of the invention

[0004] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a photovoltaic junction box reliability test method and device, which can evaluate the reliability of the photovoltaic junction box working for a long time in a water-immersed environment and improve the evaluation accuracy.

[0005] In a first aspect, the present application provides a photovoltaic junction box reliability testing method, comprising:

[0006] Performing an electrical performance test on a test sample to obtain a first test result, wherein the test sample includes a plurality of photovoltaic junction boxes connected in sequence;

[0007] Immersing the test sample in a test liquid in a test environment, and performing an aging test on the test sample;

[0008] Performing an electrical performance test on the test sample after the aging test to obtain a second test result;

[0009] The reliability of the photovoltaic junction box is determined according to the first test result and the second test result.

[0010] According to the photovoltaic junction box reliability test method of the present application, a test sample of the photovoltaic junction box is provided, and the test sample is immersed in a test liquid in a test environment to simulate the actual working environment of the photovoltaic junction box. An aging test is performed on the test sample, and an electrical performance test is performed on the test sample before and after the aging test. Based on the results of the two electrical performance tests, the reliability of the photovoltaic junction box in long-term operation in a water immersion environment is evaluated, and the accuracy of the evaluation is effectively improved.

[0011] According to one embodiment of the present application, the temperature in the test environment is constant at a first temperature, or the temperature in the test environment changes cyclically between a second temperature and a third temperature, the first temperature and the second temperature are both greater than or equal to the highest temperature in the actual working environment of the photovoltaic junction box, and the third temperature is less than or equal to the lowest temperature in the actual working environment of the photovoltaic junction box;

[0012] The boiling point of the test liquid under the pressure in the test environment is greater than the highest temperature in the test environment, the humidity in the test environment is greater than or equal to the maximum humidity in the actual working environment of the photovoltaic junction box, and the test liquid is seawater or salt water of target concentration.

[0013] According to an embodiment of the present application, the electrical performance test includes a contact resistance test, the first test result includes a first contact resistance, and the second test result includes a second contact resistance;

[0014] Determining the reliability of the photovoltaic junction box according to the first test result and the second test result includes:

[0015] calculating a resistance ratio of the second contact resistance to the first contact resistance;

[0016] Comparing the resistance ratio with a target resistance ratio to obtain a resistance comparison result;

[0017] The reliability of the photovoltaic junction box is determined according to the resistance comparison result.

[0018] According to an embodiment of the present application, the test sample further includes two test ends, and the two test ends are respectively connected to two ends of the circuit formed by the multiple photovoltaic junction boxes;

[0019] The first contact resistance and the second contact resistance both include resistances between two ends of the circuit and corresponding test ends respectively.

[0020] According to one embodiment of the present application, the photovoltaic junction box includes a diode, the electrical performance test further includes a forward voltage drop test, a reverse voltage test and / or a reverse leakage current test of the diode, the first test result includes first diode test data, and the second test result includes second diode test data;

[0021] The determining the reliability of the photovoltaic junction box according to the first test result and the second test result further includes:

[0022] Calculating a data change rate according to the first diode test data and the second diode test data;

[0023] Comparing the data change rate with the target change rate to obtain a change rate comparison result;

[0024] The reliability of the photovoltaic junction box is determined according to the change rate comparison result.

[0025] According to one embodiment of the present application, performing an aging test on the test sample includes:

[0026] Applying a forward rated current of a first target duration to the test sample to perform an aging test on the test sample; or,

[0027] applying a reverse voltage of a second target duration to the test sample to perform an aging test on the test sample; or,

[0028] A forward rated current of a third target duration and a reverse voltage of a fourth target duration are cyclically applied to the test sample to perform an aging test on the test sample.

[0029] According to one embodiment of the present application, after performing an electrical performance test on the test sample and before immersing the test sample in a test liquid in a test environment, the method further includes:

[0030] Performing glue filling and sealing on the test sample;

[0031] After performing an aging test on the test sample and before performing an electrical performance test on the test sample after the aging test, the method further includes:

[0032] The test sample after the aging test is subjected to a glue removal treatment.

[0033] According to an embodiment of the present application, the test sample further includes two test ends, the two test ends are respectively connected to two ends of the circuit formed by the multiple photovoltaic junction boxes; the photovoltaic junction box includes a diode, and the diode is short-circuited;

[0034] The first contact resistance and the second contact resistance each include a resistance between the two test terminals.

[0035] According to one embodiment of the present application, performing an aging test on the test sample includes:

[0036] A forward rated current of a first target duration is applied to the test sample to perform an aging test on the test sample.

[0037] According to one embodiment of the present application, before performing an electrical performance test on the test sample, the method further includes:

[0038] Performing glue filling and sealing on the test sample;

[0039] After performing an electrical performance test on the test sample after the aging test, the method further includes:

[0040] The test sample after the aging test is subjected to a glue removal treatment.

[0041] According to one embodiment of the present application, the test liquid is a dyed liquid;

[0042] After performing the glue removal process on the test sample after the aging test, the method further includes:

[0043] inspecting the color of the interior of the test sample;

[0044] The reliability of the photovoltaic junction box is determined based on the color inside the test sample.

[0045] According to one embodiment of the present application, before and / or after immersing the test sample in a test liquid in a test environment and performing an aging test on the test sample, the method further includes:

[0046] Performing a visual inspection on the test sample to obtain a visual inspection result;

[0047] Performing a wet leakage test on the test sample to obtain a wet leakage test result;

[0048] The reliability of the photovoltaic junction box is determined according to the appearance inspection result and the wet leakage test result.

[0049] In a second aspect, the present application provides a photovoltaic junction box reliability testing device, comprising:

[0050] A first test module, used to perform an electrical performance test on a test sample to obtain a first test result, wherein the test sample includes a plurality of photovoltaic junction boxes connected in sequence;

[0051] An aging test module, used for immersing the test sample in a test liquid in a test environment and performing an aging test on the test sample;

[0052] A second testing module is used to perform an electrical performance test on the test sample after the aging test to obtain a second test result;

[0053] A determination module is used to determine the reliability of the photovoltaic junction box according to the first test result and the second test result.

[0054] The above one or more technical solutions in the embodiments of the present application have at least one of the following technical effects:

[0055] By providing test samples of photovoltaic junction boxes, the test samples are immersed in test liquid in a test environment to simulate the real working environment of the photovoltaic junction box, and an aging test is performed on the test samples. The electrical performance tests are performed on the test samples before and after the aging test. Based on the results of the two electrical performance tests, the long-term working reliability of the photovoltaic junction box in a water immersion environment is evaluated, and the evaluation accuracy is effectively improved.

[0056] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0058] Figure 1 This is one of the flow charts of the photovoltaic junction box reliability testing method provided in the embodiment of the present application;

[0059] Figure 2 is a schematic diagram of the structure of the test sample provided in the embodiment of the present application;

[0060] Figure 3 This is the second flow chart of the photovoltaic junction box reliability testing method provided in the embodiment of the present application;

[0061] Figure 4 It is a structural schematic diagram of a photovoltaic junction box reliability testing device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0062] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0063] The following describes the photovoltaic junction box reliability testing method and device provided in the embodiments of the present application with reference to the accompanying drawings.

[0064] Among them, the photovoltaic junction box reliability test method can be applied to the terminal, and can be specifically executed by the hardware or software in the terminal. The photovoltaic junction box reliability test in this embodiment includes at least one of the electrical performance test before and after the photovoltaic junction box aging test (such as contact resistance test, etc.), the electrical performance test of the diode in the photovoltaic junction box (such as forward voltage drop test, reverse voltage test and / or reverse leakage current test), appearance inspection and wet leakage test. According to the test results before and after the aging test of the photovoltaic junction box, the reliability of the photovoltaic junction box is determined. If the test results before and after the aging test of the photovoltaic junction box meet the test requirements, it is determined that the reliability of the photovoltaic junction box is high; if any test result before and after the aging test of the photovoltaic junction box does not meet the test requirements, it is determined that the reliability of the photovoltaic junction box is low.

[0065] Figure 1 A schematic flow chart of a photovoltaic junction box reliability testing method provided in an embodiment of the present application.

[0066] like Figure 1 As shown, the photovoltaic junction box reliability testing method provided in the embodiment of the present application includes step 110, step 120, step 130 and step 140.

[0067] Step 110: Perform an electrical performance test on a test sample to obtain a first test result, where the test sample includes a plurality of photovoltaic junction boxes connected in sequence.

[0068] The photovoltaic junction box is a key part of the photovoltaic module, responsible for transmitting the current generated by the photovoltaic module cells. The photovoltaic junction box can be located on the back of the photovoltaic module or on the front of the photovoltaic module. One or more bypass diodes can be set in the photovoltaic junction box to prevent the photovoltaic module from having a hot spot effect, resulting in a loss of power generation efficiency and causing module safety risks.

[0069] According to the actual application of the photovoltaic junction box, a test sample can be prepared. In this embodiment, the test sample includes a plurality of photovoltaic junction boxes connected in sequence, that is, a plurality of photovoltaic junction boxes are used in combination in actual application. A plurality of photovoltaic junction boxes can be bonded to the test board in sequence, and a bus bar is used to connect the plurality of photovoltaic junction boxes in sequence, and the surface of the bus bar can be covered with silicone to fix and seal. The photovoltaic junction box includes a diode, and the diodes in the plurality of photovoltaic junction boxes are connected in sequence.

[0070] A plurality of photovoltaic junction boxes connected in sequence may constitute a circuit, and the test sample may further include two test terminals, the two test terminals are respectively connected to the two ends of the circuit, that is, the first photovoltaic junction box in the circuit is connected to one test terminal, and the last photovoltaic junction box in the circuit is connected to the other test terminal. For example, the photovoltaic junction box has two welding points, one welding point of the first photovoltaic junction box in the circuit is connected to one test terminal, one welding point of the last photovoltaic junction box in the circuit is connected to the other test terminal, and two welding points of other photovoltaic junction boxes in the circuit are respectively connected to one welding point of the previous photovoltaic junction box and one welding point of the next junction box.

[0071] like Figure 2 As shown, the plurality of photovoltaic junction boxes may include a positive junction box 1, an intermediate junction box 2, and a negative junction box 3. The positive junction box 1, the intermediate junction box 2, and the negative junction box 3 are sequentially bonded to the test board 4, and a bus bar is used to connect one welding point of the positive junction box 1 to one welding point of the intermediate junction box 2, and a bus bar is used to connect another welding point of the intermediate junction box 2 to one welding point of the negative junction box 3. The two test terminals include a positive test terminal 5 and a negative test terminal 6. A connecting wire is used to connect the positive test terminal 5 to another welding point of the positive junction box 1, and a connecting wire is used to connect the negative test terminal 6 to another welding point of the negative junction box 1, thereby completing the preparation of the test sample.

[0072] The electrical performance test may include contact resistance test and electrical performance test of diodes in photovoltaic junction boxes, etc., to ensure the electrical performance and safety of photovoltaic junction boxes. Before the aging test is performed on the test samples, the electrical performance test is performed on the test samples, and the results of the electrical performance test (i.e., the first test results) are recorded and saved as the basis for subsequent comparative analysis.

[0073] In some embodiments, the electrical performance test includes a contact resistance test, and the first test result includes a first contact resistance. Performing an electrical performance test on the test sample to obtain a first test result in step 110 includes: performing a contact resistance test on the test sample to obtain a first contact resistance.

[0074] The first contact resistance includes the resistance between the two ends of the circuit and the corresponding test end. Figure 2 As shown, the first contact resistance includes the resistance of the connection line between the positive electrode test terminal 5 and the positive electrode junction box 1 and the resistance of the connection line between the negative electrode test terminal 6 and the negative electrode junction box 3 .

[0075] Before the aging test, a contact resistance tester (such as a multimeter) is used to measure the resistance between the two ends of the circuit formed by multiple photovoltaic junction boxes and the corresponding test ends (such as the resistance of the connection line between the positive electrode test end and the positive electrode junction box and the resistance of the connection line between the negative electrode test end and the negative electrode junction box) to obtain the first contact resistance, and the first contact resistances R11 and R12 are recorded and saved. By performing a contact resistance test on the test sample, the electrical connection quality of the photovoltaic junction box can be detected.

[0076] In some embodiments, the electrical performance test includes a forward voltage drop test, a reverse voltage test, and / or a reverse leakage current test of a diode, and the first test result includes first diode test data. Performing an electrical performance test on the test sample in step 110 to obtain a first test result includes: performing a forward voltage drop test, a reverse voltage test, and / or a reverse leakage current test on each diode in the test sample to obtain first diode test data.

[0077] Before the aging test, a forward voltage drop test is performed on each diode to obtain a first forward voltage drop of each diode. A reverse voltage test is performed on each diode to obtain a first reverse voltage of each diode. A reverse leakage current test is performed on each diode to obtain a first reverse leakage current of each diode. The first diode test data is recorded and saved, and the first diode test data includes a first forward voltage drop VF1, a first reverse voltage VB1 and / or a first reverse leakage current IR1.

[0078] It should be noted that, since the reverse leakage current test of the diode is sensitive to temperature, the test sample can be left to stand for 10 hours at 25°C before the electrical performance test of each diode in the test sample is performed to ensure the accuracy of the test.

[0079] In some embodiments, the electrical performance test includes a contact resistance test and a forward voltage drop test, a reverse voltage test, and / or a reverse leakage current test of a diode, and the first test result includes first contact resistance and first diode test data. It should be noted that the order of the contact resistance test and the diode electrical performance test is not specifically limited.

[0080] In some embodiments, after performing an electrical performance test on the test sample in step 110, the photovoltaic junction box reliability test method further includes: performing glue filling and sealing on the test sample.

[0081] For example, after the contact resistance test and the diode forward voltage drop test, reverse voltage test and reverse leakage current test are performed on the test sample, the test sample is filled with glue, and after curing at room temperature for 14 days, the box cover is closed, leaving only the two test ends of the test sample exposed, so that the test sample can be tested later. Glue sealing can protect the components in the test sample from the influence of the external environment.

[0082] In some embodiments, before the aging test, the photovoltaic junction box reliability test method further includes:

[0083] Performing a visual inspection on the test sample to obtain a visual inspection result;

[0084] Performing a wet leakage test on the test sample to obtain a wet leakage test result;

[0085] Determine the reliability of the PV junction box based on the appearance inspection results and wet leakage test results.

[0086] For example, before the aging test and after the test sample is sealed with glue, the test sample may also be subjected to an appearance inspection and a wet leakage test, etc. The order of the appearance inspection and the wet leakage test is not specifically limited.

[0087] Appearance inspection refers to visual inspection of the appearance of the test sample to check whether the appearance is abnormal, such as checking whether the surface of the test sample has defects such as damage, cracks, stains, rust, etc. that may affect the electrical performance and durability of the photovoltaic junction box. If the appearance of the test sample is abnormal, it means that the appearance inspection of the test sample is unqualified, that is, the appearance inspection does not meet the test requirements, and it is determined that the reliability of the photovoltaic junction box is poor. The subsequent test of the test sample can be stopped, and the photovoltaic junction box reliability test can be repeated after the test sample is replaced; if the appearance of the test sample is normal, it means that the appearance inspection of the test sample is qualified, that is, the appearance inspection meets the test requirements, and the subsequent test of the test sample can continue.

[0088] The wet leakage test is to test the electrical performance and safety of the photovoltaic junction box in a humid environment. The wet leakage test is carried out on the test sample in accordance with IEC 62790. Among them, IEC 62790 is a technical standard for photovoltaic junction boxes formulated by the International Electrotechnical Commission (IEC) to ensure the safety, reliability and performance stability of photovoltaic junction boxes in all aspects such as design, manufacturing and use.

[0089] Immerse the test part of the test sample after glue sealing (i.e. the glue sealing part) in a solution with a resistivity that meets the requirements, and expose the two test ends of the test sample to the solution. Apply a certain voltage to the test sample, which can be 1000V, 1500V or 2000V according to the product model. Use an insulation resistance tester to measure the resistance between the test sample and the solution, i.e. the first insulation resistance.

[0090] Compare the measured first insulation resistance with the target insulation resistance (such as 2000MΩ). The target insulation resistance can be the minimum resistance value specified in the standard. If the measured first insulation resistance is greater than the target insulation resistance, it indicates that the wet leakage test of the test sample is qualified, that is, the wet leakage test meets the test requirements, and the test sample can continue to be tested; if the measured first insulation resistance is less than or equal to the target insulation resistance, it indicates that the wet leakage test of the test sample is unqualified, and it is determined that the reliability of the photovoltaic junction box is poor, that is, the wet leakage test does not meet the test requirements, and the subsequent testing of the test sample can be stopped, and the photovoltaic junction box reliability test can be repeated after the test sample is replaced.

[0091] When it is determined that the test sample has passed the appearance inspection and the wet leakage test, the test sample is subjected to subsequent aging test.

[0092] Step 120: Immerse the test sample in a test liquid in a test environment, and perform an aging test on the test sample.

[0093] According to the actual working environment of the photovoltaic junction box, such as temperature, humidity, light intensity and ultraviolet radiation, the test environment can be simulated to ensure that the test environment can accurately reflect the various conditions that the photovoltaic junction box may encounter in long-term use. This embodiment can simulate the test environment based on humid, rainy, water, offshore and other working environments.

[0094] In the test environment, the test sample after glue sealing is immersed in a test liquid of a certain depth. It should be noted that the two test ends of the test sample are located outside the test liquid, that is, the two test ends of the test sample extend a certain distance out of the test liquid, and the test part of the test sample (glue sealing part) is immersed in the test liquid. The test liquid matches the liquid immersed in the actual working environment of the photovoltaic junction box. For example, for offshore photovoltaic working environments, the test liquid can be seawater, or salt water with a target concentration can be used to simulate seawater. Among them, the target concentration of salt water means that the NaCl concentration in the salt water is the target concentration. For example, the target concentration is 10 to 50 g / L.

[0095] In some embodiments, the temperature in the test environment is constant at a first temperature, or the temperature in the test environment changes cyclically between a second temperature and a third temperature, the first temperature and the second temperature are both greater than or equal to the highest temperature in the real working environment of the photovoltaic junction box, and the third temperature is less than or equal to the lowest temperature in the real working environment of the photovoltaic junction box. The boiling point of the test liquid under the pressure in the test environment is greater than the highest temperature in the test environment. The humidity in the test environment is greater than or equal to the maximum humidity in the real working environment of the photovoltaic junction box, and the test liquid is seawater or salt water of target concentration.

[0096] The temperature in the test environment may be the temperature in the actual working environment of the photovoltaic junction box, and the humidity in the test environment may be the humidity in the actual working environment of the photovoltaic junction box, so as to simulate the actual working environment of the photovoltaic junction box being immersed outdoors, with high temperature and high humidity.

[0097] In order to obtain reliable test results in a short time, the temperature and humidity in the test environment can be increased, that is, the temperature in the test environment is constant at a first temperature, and the first temperature is greater than or equal to the highest temperature in the actual working environment of the photovoltaic junction box, and the humidity in the test environment is greater than or equal to the maximum humidity in the actual working environment of the photovoltaic junction box, so as to achieve the experimental effect of accelerated aging.

[0098] For example, the temperature in the test environment can be constant at 121°C, that is, the first temperature can be 121°C. The humidity in the test environment can be 100% RH (RH is relative humidity). Under standard atmospheric pressure, the temperature in the test environment is 121°C, and the water in the test liquid will boil. At this time, the operability and safety of the experiment cannot be met, so the pressure in the test environment can be increased to avoid water boiling at 121°C. For example, the test environment provides 3 standard atmospheric pressures, that is, the pressure in the test environment can be 303.975 kPa. The boiling point of water at 3 standard atmospheric pressures is 132.9°C, so water will not boil under this test environment.

[0099] The temperature in some working environments of the photovoltaic junction box varies greatly, so the temperature in the test environment can be changed cyclically to better simulate the real working environment of the photovoltaic junction box. The temperature in the test environment changes cyclically between the second temperature and the third temperature, the second temperature is greater than or equal to the highest temperature in the real working environment of the photovoltaic junction box, and the third temperature is less than or equal to the lowest temperature in the real working environment of the photovoltaic junction box.

[0100] For example, the second temperature is 121°C and the third temperature is -35°C. The temperature in the test environment is cycled for 2 hours for 365 cycles, i.e. 30 days, which can simulate a one-year outdoor cycle. In one cycle, the temperature in the test environment is first at -35°C and maintained for 50 minutes. Then, the temperature in the test environment is quickly heated to 121°C within 20 minutes and maintained for 50 minutes. The humidity in the test environment can be 100% RH, and the pressure in the test environment can be 303.975 kPa.

[0101] The temperature cycle changes in the test environment can examine the continuous release of stress in the photovoltaic junction box materials under the influence of temperature cycles (the photovoltaic junction box is composed of a variety of materials, and different materials have different thermal expansion coefficients. When the temperature changes, the expansion or contraction degree of each material is different, which may cause gaps between different materials or deformation of a certain material), and whether the sealing and waterproof performance of the photovoltaic junction box is stable. In addition, the temperature changes in the test environment are more severe, that is, the temperature change range in the test environment is greater than the temperature change range in the actual working environment of the photovoltaic junction box, achieving the experimental effect of accelerated aging.

[0102] In the test environment, with the test sample immersed in the test liquid, an aging test is performed on the test sample.

[0103] In some embodiments, performing an aging test on the test sample in step 120 includes:

[0104] Applying a forward rated current for a first target duration to the test sample to perform an aging test on the test sample; or,

[0105] applying a reverse voltage of a second target duration to the test sample to perform an aging test on the test sample; or,

[0106] A forward rated current of a third target duration and a reverse voltage of a fourth target duration are cyclically applied to the test sample to perform an aging test on the test sample.

[0107] There are three aging test methods, namely, always passing rated current in the forward direction, always loading reverse voltage, and cyclically passing rated current in the forward direction and loading reverse voltage to simulate different working conditions of the photovoltaic junction box. You can choose one of the methods to perform aging test on the test sample.

[0108] The rated current is always applied in the forward direction, that is, during the aging test, the forward rated current is always applied to the test sample. The duration of the aging test can be 350 hours, that is, the first target duration can be 350 hours. The rated current is always applied in the forward direction to simulate the state of the photovoltaic junction box working in the forward direction for a long time when the photovoltaic module has a hot spot.

[0109] Always load the reverse voltage, that is, during the aging test, always apply the reverse voltage to the test sample. The duration of the aging test can be 350 hours, that is, the second target duration can be 350 hours. The reverse voltage can be 3 times the maximum reverse withstand voltage of the photovoltaic junction box. Always loading the reverse voltage can simulate the photovoltaic junction box being in a reverse bias state for a long time when the photovoltaic module is working normally.

[0110] Cycle the forward rated current and load the reverse voltage, that is, during the aging test, first apply the forward rated current to the test sample and maintain it for the third target time, then switch to apply the reverse voltage to the test sample within the fifth target time and maintain it for the fourth target time, and cycle this action. Among them, the third target time can be 5 minutes, the fourth target time can be 1 minute, and the fifth target time can be 10ms, that is, first pass the forward rated current for 5 minutes, then switch to load the reverse voltage within 10ms, and then cycle this action after 1 minute. The duration of the aging test is 350 hours. Cycling the forward rated current and loading the reverse voltage can simulate the sudden disappearance of the obstruction when the photovoltaic module is in a hot spot state and resumes normal working state. The diode is subjected to reverse withstand voltage at high temperature, and there may be a risk of reverse breakdown.

[0111] The test environment uses 350 hours as a single test, and the single test can also be tightened according to actual conditions. Through the Arrhenius equation (Accelerated Factor) simulation calculation, a single test in the test environment in this embodiment can be equivalent to the actual outdoor working years:

[0112] AF=(RHs / RHu) 3 ×e (E / K)(1 / Tu-1 / Ts) .

[0113] Among them, RHs is the humidity in the test environment, Rhu is the humidity in the actual working environment of the photovoltaic junction box, Ts is the temperature in the test environment, Tu is the temperature in the actual working environment of the photovoltaic junction box, and AF is the acceleration factor. When RHs is 100% RH, Rhu is 80% RH, Ts is 121℃, and Tu is 45℃, it can be calculated that AF is 269.5. It can be seen that the aging test for 350 hours is equivalent to the photovoltaic junction box working for 10.76 years at 45℃, 80% RH, and a water immersion depth (salt water, sea water, etc.) of 0.1-4m.

[0114] Step 130: Perform an electrical performance test on the test sample after the aging test to obtain a second test result.

[0115] After the aging test is performed on the test sample, the electrical performance test is performed on the test sample again, and the result of the electrical performance test, i.e., the second test result, is recorded and saved. The electrical performance test of the test sample after the aging test is the same as the electrical performance test of the test sample before the aging test, so that the electrical performance test results before and after the aging test can be compared and analyzed.

[0116] In some embodiments, the electrical property test includes a contact resistance test, and the second test result includes a second contact resistance. Performing an electrical property test on the test sample after the aging test to obtain a second test result in step 130 includes: performing a contact resistance test on the test sample after the aging test to obtain a second contact resistance.

[0117] The second contact resistance includes the resistance between the two ends of the line and the corresponding test end. Figure 2 As shown, the first contact resistance includes the resistance of the connection line between the positive electrode test terminal 5 and the positive electrode junction box 1 and the resistance of the connection line between the negative electrode test terminal 6 and the negative electrode junction box 3 .

[0118] Before the aging test, a contact resistance tester (such as a multimeter) is used to measure the resistance between the two ends of the circuit formed by multiple photovoltaic junction boxes and the corresponding test ends (such as the resistance of the connecting line between the positive test end and the positive junction box and the resistance of the connecting line between the negative test end and the negative junction box) to obtain the second contact resistance, and the second contact resistances R21 and R22 are recorded and saved.

[0119] During the aging test, the test samples are affected by the test environment such as temperature and humidity, which leads to an increase in contact resistance. However, excessive contact resistance may lead to problems such as poor contact, heating, and even short circuit of the photovoltaic junction box. Therefore, it is necessary to compare and analyze the contact resistance of the test samples before and after the aging test.

[0120] In some embodiments, the electrical performance test includes a forward voltage drop test, a reverse voltage test, and / or a reverse leakage current test of a diode, and the second test result includes second diode test data. Performing an electrical performance test on the test sample after the aging test in step 130 to obtain the second test result includes: performing a forward voltage drop test, a reverse voltage test, and / or a reverse leakage current test on each diode in the test sample after the aging test to obtain the second diode test data.

[0121] After the aging test, a forward voltage drop test is performed on each diode to obtain a second forward voltage drop of each diode. A reverse voltage test is performed on each diode to obtain a second reverse voltage of each diode. A reverse leakage current test is performed on each diode to obtain a second reverse leakage current of each diode. Second diode test data is recorded and saved, and the second diode test data includes a second forward voltage drop VF2, a second reverse voltage VB2, and / or a second reverse leakage current IR2.

[0122] It should be noted that, since the reverse leakage current test of the diode is sensitive to temperature, the test sample can be left to stand for 10 hours at 25°C before the electrical performance test of each diode in the test sample is performed to ensure the accuracy of the test.

[0123] In some embodiments, the electrical performance test includes a contact resistance test and a forward voltage drop test, a reverse voltage test and / or a reverse leakage current test of a diode, and the second test result includes second contact resistance and second diode test data.

[0124] It should be noted that the order of the contact resistance test and the diode electrical performance test is not specifically limited. The electrical performance test may also include other types of tests, which are set and adjusted according to actual needs and are not specifically limited here.

[0125] Step 140: Determine the reliability of the photovoltaic junction box according to the first test result and the second test result.

[0126] The second test result is compared and analyzed with the first test result to evaluate the performance change of the photovoltaic junction box during the aging process. According to the performance change of the photovoltaic junction box during the aging process, the reliability of the photovoltaic junction box is evaluated and the evaluation accuracy is improved.

[0127] In some embodiments, the electrical performance test includes a contact resistance test, the first test result includes a first contact resistance, and the second test result includes a second contact resistance. Determining the reliability of the photovoltaic junction box according to the first test result and the second test result in step 140 includes:

[0128] calculating a resistance ratio of the second contact resistance to the first contact resistance;

[0129] Comparing the resistance ratio with the target resistance ratio to obtain a resistance comparison result;

[0130] Based on the resistance comparison results, the reliability of the photovoltaic junction box is determined.

[0131] The contact resistance of the test sample after the aging test becomes larger, but the change cannot be too large. Obtain the first contact resistance before the aging test and the second contact resistance after the aging test, and calculate the resistance ratio of the second contact resistance to the first contact resistance. Among them, the first contact resistance includes the resistances R11 and R12 between the two ends of the circuit formed by multiple photovoltaic junction boxes and the corresponding test ends, and the second contact resistance includes the resistances R21 and R22 between the two ends of the circuit formed by multiple photovoltaic junction boxes and the corresponding test ends. Calculate the resistance ratio R12 / R11 between the resistor R12 and the resistor R11 and the resistance ratio R22 / R21 between the resistor R22 and the resistor R21 respectively.

[0132] The resistance ratio R12 / R11 and the resistance ratio R22 / R21 are compared with the target resistance ratio (such as 1.5) respectively. If the resistance ratio R12 / R11 is less than or equal to the target resistance ratio, and the resistance ratio R22 / R21 is less than or equal to the target resistance ratio, such as R12 / R11≤1.5 and R22 / R21≤1.5, then the resistance comparison result is determined to be that the contact resistance test of the test sample is qualified, that is, the contact resistance test meets the test requirements; if the resistance ratio R12 / R11 is greater than the target resistance ratio, or the resistance ratio R22 / R21 is greater than the target resistance ratio, such as R22 / R21>1.5 or R22 / R21>1.5, then the resistance comparison result is determined to be that the contact resistance test of the test sample is unqualified, that is, the contact resistance test does not meet the test requirements.

[0133] In the case where the electrical performance test includes a contact resistance test, if the contact resistance test meets the test requirements, the photovoltaic junction box can be evaluated to have good reliability; if the contact resistance test does not meet the test requirements, the photovoltaic junction box can be evaluated to have poor reliability.

[0134] In some embodiments, the electrical performance test includes a forward voltage drop test, a reverse voltage test, and / or a reverse leakage current test of a diode, the first test result includes first diode test data, and the second test result includes second diode test data. Determining the reliability of the photovoltaic junction box according to the first test result and the second test result in step 140 also includes:

[0135] Calculating a data change rate according to the first diode test data and the second diode test data;

[0136] Compare the data change rate with the target change rate to obtain a change rate comparison result;

[0137] The reliability of the PV junction box is determined based on the change rate comparison results.

[0138] The diode test data in the test sample after the aging test changes, but the change cannot be too large. Obtain the first diode test data before the aging test and the second diode test data after the aging test, calculate the difference between the second diode test data and the first diode test data, and then calculate the ratio of the difference to the first diode test data. The ratio is the data change rate.

[0139] For example, the first diode test data includes the first forward voltage drop VF1, the first reverse voltage VB1 and the first reverse leakage current IR1, and the second diode test data includes the second forward voltage drop VF2, the second reverse voltage VB2 and the second reverse leakage current IR2. The data change rate includes the forward voltage drop change rate, the reverse voltage change rate and the reverse leakage current change rate. The forward voltage drop change rate (VF2-VF1) / VF1, the reverse voltage change rate (VB2-VB1) / VB1 and the reverse leakage current change rate (IR2-IR1) / IR1 are calculated respectively.

[0140] Compare the forward voltage drop change rate (VF2-VF1) / VF1, the reverse voltage change rate (VB2-VB1) / VB1 and the reverse leakage current change rate (IR2-IR1) / IR1 with the target change rate (such as 2%) respectively. If the forward voltage drop change rate (VF2-VF1) / VF1, the reverse voltage change rate (VB2-VB1) / VB1 and the reverse leakage current change rate (IR2-IR1) / IR1 are all less than or equal to the target change rate, such as (VF2-VF1) / VF1≤2%, (VB2-VB1) / VB1≤2% and (IR2-IR1) / IR1≤2%, then determine The change rate comparison result is that the electrical performance test of the diode in the test sample is qualified, that is, the electrical performance test of the diode meets the test requirements; if the forward voltage drop change rate (VF2-VF1) / VF1, the reverse voltage change rate (VB2-VB1) / VB1 or the reverse leakage current change rate (IR2-IR1) / IR1 is greater than the target change rate (such as 2%), such as (VF2-VF1) / VF1>2%, (VB2-VB1) / VB1>2% and (IR2-IR1) / IR1>2%, then it is determined that the change rate comparison result is that the electrical performance test of the diode in the test sample is unqualified, that is, the electrical performance test of the diode does not meet the test requirements.

[0141] In the case where the electrical performance test includes a diode electrical performance test, if the diode electrical performance test meets the test requirements, the photovoltaic junction box can be evaluated to have good reliability; if the diode electrical performance test does not meet the test requirements, the photovoltaic junction box can be evaluated to have poor reliability.

[0142] In some embodiments, the electrical performance test includes a contact resistance test and a forward voltage drop test, a reverse voltage test, and / or a reverse leakage current test of a diode, the first test result includes a first contact resistance and a first diode test data, and the second test result includes a second contact resistance and a second diode test data. Determining the reliability of the photovoltaic junction box according to the first test result and the second test result in step 140 includes:

[0143] calculating a resistance ratio of the second contact resistance to the first contact resistance;

[0144] Comparing the resistance ratio with the target resistance ratio to obtain a resistance comparison result;

[0145] Calculating a data change rate according to the first diode test data and the second diode test data;

[0146] Compare the data change rate with the target change rate to obtain a change rate comparison result;

[0147] The reliability of the photovoltaic junction box is determined based on the resistance comparison results and the change rate comparison results.

[0148] When it is determined that the resistance comparison result is that the contact resistance test of the test sample is qualified, and the change rate comparison result is that the diode electrical performance test in the test sample is qualified, both the contact resistance test and the diode electrical performance test meet the test requirements, and the photovoltaic junction box can be evaluated as having good reliability; when it is determined that the resistance comparison result is that the contact resistance test of the test sample is unqualified, or the change rate comparison result is that the diode electrical performance test in the test sample is unqualified, the contact resistance test or the diode electrical performance test does not meet the test requirements, and the photovoltaic junction box can be evaluated as having poor reliability.

[0149] For the test samples after glue sealing, it is necessary to remove the glue before conducting electrical performance test. The glue removal process refers to removing the colloid formed on the test sample during glue sealing to expose each photovoltaic junction box in the test sample.

[0150] In some embodiments, after performing an aging test on the test sample in step 120 and before performing an electrical performance test on the test sample after the aging test in step 130, the photovoltaic junction box reliability testing method further includes: performing a glue removal process on the test sample after the aging test.

[0151] First, clean the test sample after the glue is sealed and make its surface dry. Then, dig out the glue from the test sample to expose each photovoltaic junction box in the test sample so as to conduct electrical performance tests on the test sample, such as contact resistance test, diode forward voltage drop test, reverse voltage test and / or reverse leakage current test, etc.

[0152] In some embodiments, the test liquid is a dyed liquid, for example, 1% red ink is added to salt water or seawater to make the test liquid a red liquid. It should be noted that the test liquid can also be a liquid of other colors, as long as it is different from the color of the photovoltaic junction box and the glue. After the step of digging out the glue from the test sample after the aging test, the photovoltaic junction box reliability test method also includes:

[0153] Check the color inside the test sample;

[0154] Determine the reliability of the photovoltaic junction box based on the color inside the test sample.

[0155] During the aging test, the test sample sealed with glue is immersed in the test liquid. After the aging test and the glue removal of the test sample, check the color inside the test sample, such as the color of the diode conductive sheet and the welding point, to detect whether there is water vapor intrusion into the test sample sealed with glue. If there are staining marks inside the test sample, such as red marks, it indicates that water vapor has intruded into the test sample sealed with glue, and it is determined that the reliability of the photovoltaic junction box is poor; if there are no staining marks inside the test sample, such as red marks, it indicates that no water vapor has intruded into the test sample sealed with glue, and the test sample can continue to be tested, such as electrical performance testing of the test sample.

[0156] In some embodiments, after performing an aging test on the test sample, the photovoltaic junction box reliability test method further includes:

[0157] Performing a visual inspection on the test sample to obtain a visual inspection result;

[0158] Performing a wet leakage test on the test sample to obtain a wet leakage test result;

[0159] Determine the reliability of the PV junction box based on the appearance inspection results and wet leakage test results.

[0160] For example, after the aging test and before the test sample is subjected to the glue removal process, the test sample may be subjected to an appearance inspection and a wet leakage test, etc. The order of the appearance inspection and the wet leakage test is not specifically limited.

[0161] The appearance inspection method after the aging test can be the same as the appearance inspection method before the aging test, and will not be described in detail here. Perform an appearance inspection on the test sample after the aging test. If the appearance of the test sample after the aging test is detected to be abnormal, it indicates that the appearance inspection of the test sample after the aging test is unqualified, that is, the appearance inspection does not meet the test requirements, and it is determined that the reliability of the photovoltaic junction box is poor. Subsequent testing of the test sample can be stopped, and the photovoltaic junction box reliability test can be repeated after the test sample is replaced; if the appearance of the test sample after the aging test is normal, it indicates that the appearance inspection of the test sample after the aging test is qualified, that is, the appearance inspection meets the test requirements, and subsequent testing of the test sample can continue.

[0162] The wet leakage test method after the aging test can be the same as the wet leakage test method before the aging test, and will not be described in detail here. Perform a wet leakage test on the test sample after the aging test to obtain a second insulation resistance. Compare the second insulation resistance with the target insulation resistance (such as 2000MΩ). If the second insulation resistance is greater than the target insulation resistance, it is determined that the wet leakage test of the test sample after the aging test is qualified, that is, the wet leakage test meets the test requirements, and the test sample can continue to be tested subsequently; if the second insulation resistance is less than or equal to the target insulation resistance, it indicates that the wet leakage test of the test sample after the aging test is unqualified, that is, the wet leakage test does not meet the test requirements, and it is determined that the reliability of the photovoltaic junction box is poor, and the subsequent testing of the test sample can be stopped. After replacing the test sample, the reliability test of the photovoltaic junction box can be re-performed.

[0163] It should be noted that, based on the reliability assessment of the photovoltaic junction box, improvement measures can be proposed for the design, production, and use of the photovoltaic junction box to optimize the reliability and performance of the photovoltaic junction box.

[0164] In some embodiments, the test sample includes a plurality of photovoltaic junction boxes connected in sequence, the photovoltaic junction boxes include diodes, and the diodes are short-circuited. The test sample also includes two test terminals, and the two test terminals are respectively connected to the two ends of the circuit formed by the plurality of photovoltaic junction boxes. Among them, the diodes in each photovoltaic junction box in the test sample are short-circuited by a bus bar.

[0165] Perform an electrical performance test on the test sample to obtain a first test result. In some embodiments, the electrical performance test may include a contact resistance test, and the first test result may include a first contact resistance. The first contact resistance includes the resistance between the two test terminals, and the first contact resistance R1 is recorded and saved. It should be noted that in the case where the diode in the test sample is short-circuited, there is no need to perform electrical performance tests such as a forward voltage drop test, a reverse voltage test, and a reverse leakage current test on the diode in the test sample.

[0166] In some embodiments, before the step of performing an electrical performance test on the test sample, the photovoltaic junction box reliability test method further includes: sealing the test sample with glue. After the test sample is filled with glue, it is cured at room temperature for 14 days, and the box cover is closed, leaving only two test ends of the test sample exposed, so as to perform an electrical performance test on the test sample.

[0167] After the test sample is sealed with glue, the test sample can also be subjected to appearance inspection and wet leakage test. The appearance inspection and wet leakage test in this embodiment are the same as those in the above embodiment, and will not be described in detail here. The order of appearance inspection, wet leakage test and contact resistance test before aging test is not specifically limited.

[0168] The test sample is immersed in the test liquid in the test environment, and an aging test is performed on the test sample. The test environment in this embodiment is the same as the test environment in the above embodiment, and will not be described in detail here.

[0169] In some embodiments, the step of performing an aging test on the test sample includes: applying a forward rated current of a first target duration to the test sample to perform an aging test on the test sample. During the aging test, the forward rated current is always applied to the test sample. The duration of the aging test can be 350 hours, that is, the first target duration can be 350 hours. Always passing the rated current in the forward direction can simulate the situation where the photovoltaic junction box works in the forward direction for a long time when the photovoltaic module has a hot spot.

[0170] Perform an electrical performance test on the test sample after the aging test to obtain a second test result. In some embodiments, the electrical performance test may include a contact resistance test, and the second test result may include a second contact resistance. The second contact resistance includes the resistance between the two test ends, and the second contact resistance R2 is recorded and saved. It should be noted that in the case where the diode in the test sample is short-circuited, there is no need to perform electrical performance tests such as forward voltage drop test, reverse voltage test and reverse leakage current test on the diode in the test sample after the aging test.

[0171] In some embodiments, after the step of performing an electrical performance test on the test sample after the aging test, the photovoltaic junction box reliability test method further includes: performing a glue digging process on the test sample after the aging test. During the aging test, the test liquid immersed in the test sample can be a dyed liquid. After the test sample is subjected to the glue digging process, the color inside the test sample is checked to detect whether there is water vapor intrusion in the test sample after the glue is sealed.

[0172] Before the test sample is subjected to the glue removal treatment, the test sample after the aging test may also be subjected to an appearance inspection and a wet leakage test. The appearance inspection and the wet leakage test in this embodiment are the same as those in the above-mentioned embodiment, and will not be described in detail here. The order of the appearance inspection after the aging test, the wet leakage test, and the contact resistance test is not specifically limited.

[0173] The reliability of the photovoltaic junction box is determined according to the first test result and the second test result. The first test result includes the first contact resistance R1, and the second test result includes the second contact resistance R2. The resistance ratio R2 / R1 between the second contact resistance R2 and the first contact resistance R1 is calculated, and the resistance ratio R2 / R1 is compared with the target resistance ratio (such as 1.5). If the resistance ratio R2 / R1 is less than or equal to the target resistance ratio, such as R2 / R1≤1.5, it is determined that the contact resistance test of the test sample is qualified, that is, the contact resistance test meets the test requirements; if the resistance ratio R2 / R1 is greater than the target resistance ratio, such as R2 / R1>1.5, it is determined that the contact resistance test of the test sample is unqualified, that is, the contact resistance test does not meet the test requirements.

[0174] In the case where the electrical performance test includes a contact resistance test, if the contact resistance test meets the test requirements, the photovoltaic junction box can be evaluated to have good reliability; if the contact resistance test does not meet the test requirements, the photovoltaic junction box can be evaluated to have poor reliability.

[0175] like Figure 3 As shown, the embodiment of the present application also provides a photovoltaic junction box reliability testing method, including steps 210 to 370.

[0176] Step 210: Provide a test sample, where the test sample includes a plurality of photovoltaic junction boxes connected in sequence, and the photovoltaic junction boxes include diodes.

[0177] For example, the test sample includes a positive electrode terminal box, an intermediate terminal box, and a negative electrode terminal box which are connected in sequence.

[0178] Step 220: Perform a contact resistance test on the test sample to obtain a first contact resistance.

[0179] For example, the test sample further includes two test terminals, and the two test terminals are respectively connected to the two ends of the circuit formed by the plurality of photovoltaic junction boxes. The first contact resistance includes the resistance between the two ends of the circuit and the corresponding test terminals. The first contact resistance is recorded and saved as R11=1.8Ω and R12=1.9Ω.

[0180] Step 220: Perform an electrical performance test on the diode in the test sample to obtain first diode test data.

[0181] For example, after standing for 10 hours at 25°C, the diode in the test sample is subjected to an electrical performance test, which includes a forward voltage drop test, a reverse voltage test, and a reverse leakage current test. The first diode test data is recorded and saved, including the first forward voltage drop VF1=490mV, the first reverse voltage VB1=51V, and the first direction leakage current IR1=20uA.

[0182] Step 240: Fill the test sample with glue and seal it.

[0183] For example, the test sample is filled with glue, cured at room temperature for 14 days, and then the box lid is closed.

[0184] Step 250: Perform a visual inspection on the test sample and determine whether the appearance inspection is qualified.

[0185] For example, a visual inspection is performed on the appearance of the test sample, and if there is no abnormality in the appearance, it is determined that the appearance inspection is qualified.

[0186] Step 260: Perform a wet leakage test on the test sample and determine whether the wet leakage test is qualified.

[0187] For example, a voltage of 1500V is applied to the test sample, and it is detected that the insulation resistance is greater than 2000MΩ, which determines that the wet leakage test is qualified.

[0188] Step 270: Immerse the test sample in the dyed test liquid under the test environment, and perform an aging test on the test sample.

[0189] For example, the temperature in the test environment is 121°C, the humidity is 100% RH (100% humidity), the pressure is 303.975 kPa, the test liquid is salt water (NaCl concentration is 40g / L), and the salt water is doped with 1% red ink, and the test liquid is red. In the test environment, the test sample is immersed in the dyed test liquid at a depth of 1m, and the forward rated current is passed through the test sample for 350 hours.

[0190] Step 280: Perform an appearance inspection on the test sample after the aging test, and determine whether the appearance inspection is qualified.

[0191] For example, a visual inspection is performed on the appearance of the test sample after the aging test, and if there is no abnormality in the appearance, it is determined that the appearance inspection is qualified.

[0192] Step 290: Perform a wet leakage test on the test sample after the aging test, and determine whether the wet leakage test is qualified.

[0193] For example, a voltage of 1500V is applied to the test sample after the aging test, and the insulation resistance is detected to be greater than 2000MΩ, which determines that the wet leakage test is qualified.

[0194] Step 310: Perform glue removal processing on the test sample.

[0195] For example, clean the test sample, dry its surface, and perform glue removal on the test sample.

[0196] Step 320: Check whether the interior of the test sample is stained.

[0197] For example, no red marks were found when observing the inside and bottom of the test sample, as well as the diode conductive sheet and welding points.

[0198] Step 330: Perform a contact resistance test on the test sample to obtain a second contact resistance.

[0199] For example, the second contact resistance includes the resistance between the two ends of the circuit formed by the plurality of photovoltaic junction boxes and the corresponding test ends, respectively. The second contact resistance is recorded and saved as R21=2Ω and R22=2.05Ω.

[0200] Step 340: Determine whether the contact resistance test is qualified according to the first contact resistance and the second contact resistance.

[0201] For example, the ratio of the second contact resistance to the first contact resistance is calculated to be R12 / R11≤1.5 and R22 / R21≤1.5, and it is determined that the contact resistance test is qualified.

[0202] Step 350: Perform an electrical performance test on the diode in the test sample to obtain second diode test data.

[0203] For example, after standing for 10 hours at 25°C, the diode in the test sample is tested for electrical performance again, and the electrical performance test includes forward voltage drop test, reverse voltage test and reverse leakage current test. The second diode test data is recorded and saved, including the second forward voltage drop VF2 = 492mV, the second reverse voltage VB2 = 51V, and the second direction leakage current IR2 = 23uA.

[0204] Step 360: Determine whether the electrical performance test of the diode is qualified based on the first diode test data and the second diode test data.

[0205] For example, compared with the first forward voltage drop VF1, the first reverse voltage VB1 and the first direction leakage current IR1, the change rate of the second forward voltage drop VF2, the second reverse voltage VB2 and the second direction leakage current IR2 is within 2%, and it is determined that the electrical performance test of the diode is qualified.

[0206] Step 370: If the appearance inspection, wet leakage test, contact resistance test and diode electrical performance test are all qualified, it is determined that the photovoltaic junction box has high reliability; otherwise, it is determined that the photovoltaic junction box has low reliability.

[0207] Through the reliability test of photovoltaic junction boxes, it can be ensured that the photovoltaic junction boxes maintain stable performance and a long service life in a complex and changeable working environment, providing a strong guarantee for the safe and stable operation of the photovoltaic power generation system.

[0208] According to the photovoltaic junction box reliability test method provided in the embodiment of the present application, a test sample of the photovoltaic junction box is provided, and the test sample is immersed in a test liquid in a test environment to simulate the actual working environment of the photovoltaic junction box. An aging test is performed on the test sample, and an electrical performance test is performed on the test sample before and after the aging test. Based on the results of the two electrical performance tests, the reliability of the photovoltaic junction box in long-term operation in a water immersion environment is evaluated, and the accuracy of the evaluation is effectively improved.

[0209] The photovoltaic junction box reliability test method provided in the embodiment of the present application can be executed by a photovoltaic junction box reliability test device. In the embodiment of the present application, the photovoltaic junction box reliability test method is executed by a photovoltaic junction box reliability test device as an example to illustrate the photovoltaic junction box reliability test device provided in the embodiment of the present application.

[0210] like Figure 4 As shown, the photovoltaic junction box reliability testing device provided in the embodiment of the present application includes a first testing module 410 , an aging testing module 420 , a second testing module 430 and a determination module 440 .

[0211] A first test module 410 is used to perform an electrical performance test on a test sample to obtain a first test result, wherein the test sample includes a plurality of photovoltaic junction boxes connected in sequence;

[0212] An aging test module 420, used to immerse the test sample in a test liquid in a test environment and perform an aging test on the test sample;

[0213] The second test module 430 is used to perform an electrical performance test on the test sample after the aging test to obtain a second test result;

[0214] The determination module 440 is used to determine the reliability of the photovoltaic junction box according to the first test result and the second test result.

[0215] According to the photovoltaic junction box reliability testing device provided in the embodiment of the present application, a test sample of the photovoltaic junction box is provided, and the test sample is immersed in a test liquid in a test environment to simulate the actual working environment of the photovoltaic junction box. An aging test is performed on the test sample, and an electrical performance test is performed on the test sample before and after the aging test. Based on the results of the two electrical performance tests, the reliability of the photovoltaic junction box in long-term operation in a water immersion environment is evaluated, and the accuracy of the evaluation is effectively improved.

[0216] In some embodiments, the temperature in the test environment is constant at a first temperature, or the temperature in the test environment changes cyclically between a second temperature and a third temperature, the first temperature and the second temperature are both greater than or equal to the highest temperature in the actual working environment of the photovoltaic junction box, and the third temperature is less than or equal to the lowest temperature in the actual working environment of the photovoltaic junction box;

[0217] The boiling point of the test liquid under the pressure in the test environment is greater than the highest temperature in the test environment, the humidity in the test environment is greater than or equal to the maximum humidity in the actual working environment of the photovoltaic junction box, and the test liquid is seawater or salt water of target concentration.

[0218] In some embodiments, the electrical performance test includes a contact resistance test, the first test result includes a first contact resistance, and the second test result includes a second contact resistance. The determination module 440 is further configured to:

[0219] calculating a resistance ratio of the second contact resistance to the first contact resistance;

[0220] Comparing the resistance ratio with a target resistance ratio to obtain a resistance comparison result;

[0221] The reliability of the photovoltaic junction box is determined according to the resistance comparison result.

[0222] In some embodiments, the test sample further includes two test ends, and the two test ends are respectively connected to two ends of the circuit formed by the plurality of photovoltaic junction boxes;

[0223] The first contact resistance and the second contact resistance both include resistances between two ends of the circuit and corresponding test ends respectively.

[0224] In some embodiments, the photovoltaic junction box includes a diode, the electrical performance test also includes a forward voltage drop test, a reverse voltage test and / or a reverse leakage current test of the diode, the first test result includes first diode test data, and the second test result includes second diode test data. The determination module 440 is also used to:

[0225] Calculating a data change rate according to the first diode test data and the second diode test data;

[0226] Comparing the data change rate with the target change rate to obtain a change rate comparison result;

[0227] The reliability of the photovoltaic junction box is determined according to the change rate comparison result.

[0228] In some embodiments, the aging test module 420 is further configured to:

[0229] Applying a forward rated current of a first target duration to the test sample to perform an aging test on the test sample; or,

[0230] applying a reverse voltage of a second target duration to the test sample to perform an aging test on the test sample; or,

[0231] A forward rated current of a third target duration and a reverse voltage of a fourth target duration are cyclically applied to the test sample to perform an aging test on the test sample.

[0232] In some embodiments, the device further includes a glue pouring module, and the glue pouring module is used to:

[0233] The test sample is sealed by glue filling.

[0234] In some embodiments, the device further includes a glue digging module, and the glue digging module is used to:

[0235] The test sample after the aging test is subjected to a glue removal treatment.

[0236] In some embodiments, the test sample further includes two test ends, the two test ends are respectively connected to two ends of the circuit formed by the plurality of photovoltaic junction boxes; the photovoltaic junction box includes a diode, and the diode is short-circuited;

[0237] The first contact resistance and the second contact resistance each include a resistance between the two test terminals.

[0238] In some embodiments, the aging test module 420 is further configured to:

[0239] A forward rated current of a first target duration is applied to the test sample to perform an aging test on the test sample.

[0240] In some embodiments, the test liquid is a dyed liquid. The device also includes a color inspection module, which is used to:

[0241] inspecting the color of the interior of the test sample;

[0242] The reliability of the photovoltaic junction box is determined based on the color inside the test sample.

[0243] In some embodiments, the device further comprises a checking module, the checking module being configured to:

[0244] Performing a visual inspection on the test sample to obtain a visual inspection result;

[0245] Performing a wet leakage test on the test sample to obtain a wet leakage test result;

[0246] The reliability of the photovoltaic junction box is determined according to the appearance inspection result and the wet leakage test result.

[0247] An embodiment of the present application also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the various processes of the above-mentioned photovoltaic junction box reliability testing method embodiment are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0248] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory ROM, a random access memory RAM, a magnetic disk or an optical disk.

[0249] An embodiment of the present application also provides a computer program product, including a computer program, which implements the above-mentioned photovoltaic junction box reliability testing method when executed by a processor.

[0250] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory ROM, a random access memory RAM, a magnetic disk or an optical disk.

[0251] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned photovoltaic junction box reliability test method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0252] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0253] The terms "first", "second", etc. in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more.

[0254] In the description of the present application, “plurality” means two or more.

[0255] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0256] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A photovoltaic junction box reliability testing method, characterized in that: include: Performing an electrical performance test on a test sample to obtain a first test result, wherein the test sample includes a plurality of photovoltaic junction boxes connected in sequence; Immersing the test sample in a test liquid in a test environment, and performing an aging test on the test sample; Performing an electrical performance test on the test sample after the aging test to obtain a second test result; The reliability of the photovoltaic junction box is determined according to the first test result and the second test result.

2. The photovoltaic junction box reliability testing method according to claim 1, characterized in that: The temperature in the test environment is constant at a first temperature, or the temperature in the test environment changes cyclically between a second temperature and a third temperature, the first temperature and the second temperature are both greater than or equal to the highest temperature in the actual working environment of the photovoltaic junction box, and the third temperature is less than or equal to the lowest temperature in the actual working environment of the photovoltaic junction box; The boiling point of the test liquid under the pressure in the test environment is greater than the highest temperature in the test environment, the humidity in the test environment is greater than or equal to the maximum humidity in the actual working environment of the photovoltaic junction box, and the test liquid is seawater or salt water of target concentration.

3. The photovoltaic junction box reliability testing method according to claim 1, characterized in that: The electrical performance test includes a contact resistance test, the first test result includes a first contact resistance, and the second test result includes a second contact resistance; Determining the reliability of the photovoltaic junction box according to the first test result and the second test result includes: calculating a resistance ratio of the second contact resistance to the first contact resistance; Comparing the resistance ratio with a target resistance ratio to obtain a resistance comparison result; The reliability of the photovoltaic junction box is determined according to the resistance comparison result.

4. The photovoltaic junction box reliability testing method according to claim 3, characterized in that: The test sample further includes two test ends, and the two test ends are respectively connected to two ends of the circuit formed by the plurality of photovoltaic junction boxes; The first contact resistance and the second contact resistance both include resistances between two ends of the circuit and corresponding test ends respectively.

5. The photovoltaic junction box reliability testing method according to claim 4, characterized in that: The photovoltaic junction box includes a diode, the electrical performance test further includes a forward voltage drop test, a reverse voltage test and / or a reverse leakage current test of the diode, the first test result includes first diode test data, and the second test result includes second diode test data; The determining the reliability of the photovoltaic junction box according to the first test result and the second test result further includes: Calculating a data change rate according to the first diode test data and the second diode test data; Comparing the data change rate with the target change rate to obtain a change rate comparison result; The reliability of the photovoltaic junction box is determined according to the change rate comparison result.

6. The photovoltaic junction box reliability testing method according to claim 5, characterized in that: The step of performing an aging test on the test sample comprises: Applying a forward rated current of a first target duration to the test sample to perform an aging test on the test sample; or, applying a reverse voltage of a second target duration to the test sample to perform an aging test on the test sample; or, A forward rated current of a third target duration and a reverse voltage of a fourth target duration are cyclically applied to the test sample to perform an aging test on the test sample.

7. The photovoltaic junction box reliability testing method according to claim 5, characterized in that: After performing the electrical performance test on the test sample and before immersing the test sample in the test liquid in the test environment, the method further includes: Performing glue filling and sealing on the test sample; After performing an aging test on the test sample and before performing an electrical performance test on the test sample after the aging test, the method further includes: The test sample after the aging test is subjected to a glue removal treatment.

8. The photovoltaic junction box reliability testing method according to claim 3, characterized in that: The test sample further includes two test ends, and the two test ends are respectively connected to two ends of the circuit formed by the plurality of photovoltaic junction boxes; the photovoltaic junction box includes a diode, and the diode is short-circuited; The first contact resistance and the second contact resistance each include a resistance between the two test terminals.

9. The photovoltaic junction box reliability testing method according to claim 8, characterized in that: The step of performing an aging test on the test sample comprises: A forward rated current of a first target duration is applied to the test sample to perform an aging test on the test sample.

10. The photovoltaic junction box reliability testing method according to claim 8, characterized in that: Before performing an electrical performance test on the test sample, the method further comprises: Performing glue filling and sealing on the test sample; After performing an electrical performance test on the test sample after the aging test, the method further includes: The test sample after the aging test is subjected to a glue removal treatment.

11. The photovoltaic junction box reliability testing method according to claim 7 or 10, characterized in that: The test liquid is a dyeing liquid; After performing the glue removal process on the test sample after the aging test, the method further includes: inspecting the color of the interior of the test sample; The reliability of the photovoltaic junction box is determined based on the color inside the test sample.

12. The photovoltaic junction box reliability testing method according to claim 1, characterized in that: Before and / or after immersing the test sample in a test liquid in a test environment and performing an aging test on the test sample, the method further comprises: Performing a visual inspection on the test sample to obtain a visual inspection result; Performing a wet leakage test on the test sample to obtain a wet leakage test result; The reliability of the photovoltaic junction box is determined according to the appearance inspection result and the wet leakage test result.

13. A photovoltaic junction box reliability testing device, characterized in that: include: A first test module, used to perform an electrical performance test on a test sample to obtain a first test result, wherein the test sample includes a plurality of photovoltaic junction boxes connected in sequence; An aging test module, used for immersing the test sample in a test liquid in a test environment and performing an aging test on the test sample; A second testing module is used to perform an electrical performance test on the test sample after the aging test to obtain a second test result; A determination module is used to determine the reliability of the photovoltaic junction box according to the first test result and the second test result.

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