Method for testing temperature coefficient of photovoltaic module

Abstract

The application discloses a photovoltaic module temperature coefficient test method, comprising the following steps: S11, determining the position of a temperature test point on a photovoltaic module to be tested, and keeping the temperature of the position of the temperature test point of the photovoltaic module; S12, placing the obtained photovoltaic module in an environmental test chamber for heating; S13, taking the photovoltaic module out of the environmental test chamber, stopping the keeping of the temperature of the infrared temperature probe test point, placing the infrared temperature probe at the infrared probe temperature test point, continuing to keep the temperature of the thermocouple temperature test point, and placing the thermocouple at the thermocouple temperature test point; S14, when the difference between the temperatures displayed by the infrared temperature probe and the thermocouple is less than a preset value, stopping the keeping of the temperature of the thermocouple temperature test point; and with the decrease of the temperature of the photovoltaic module, testing the I-V characteristic value of the photovoltaic module at a preset temperature interval; the effect that the temperature span is greater than or equal to 30 DEG C required under the condition that the uniformity of the temperatures of all the test points is ± 2 DEG C can be realized.

Description

Technical Field

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

[0002] A solar cell is a device that uses the photoelectric conversion principle to convert solar radiation into electrical energy through semiconductor materials. Its main component, silicon, is the most abundant element on Earth. In addition, solar energy is inexhaustible, so solar cells are a green new energy source with broad development prospects.

[0003] Currently, multiple solar cells require a series of welding and encapsulation processes to be manufactured into photovoltaic modules in order to generate electricity effectively. Before being put on the market, photovoltaic modules need to undergo a series of tests to prove their reliability or obtain relevant product certifications. For example, photovoltaic module reliability testing includes performance testing, environmental testing, mechanical testing, safety testing, etc. This invention relates to a method for testing the temperature coefficient of photovoltaic modules.

[0004] According to Clause 4.4 of ICE 60891:2009, the temperature coefficient test of photovoltaic modules requires a test temperature span greater than or equal to 30°C, and a temperature uniformity of ±2°C at each test point. However, existing test methods, while meeting the requirement of ±2°C temperature uniformity at each test point, cannot meet the requirement of a test temperature span greater than or equal to 30°C. Summary of the Invention

[0005] The purpose of this application is to provide a method for testing the temperature coefficient of photovoltaic modules, which can achieve the effect of testing a temperature range greater than or equal to 30℃ while meeting the requirement that the temperature uniformity at each test point is ±2℃.

[0006] To achieve the above objectives, this application provides the following technical solution: a method for testing the temperature coefficient of a photovoltaic module, comprising the following steps: Step S11, determining the location of a temperature test point on the photovoltaic module to be tested, and insulating the location of the temperature test point on the photovoltaic module, wherein the temperature test point includes at least one infrared temperature probe test point and at least one thermocouple temperature test point; Step S12, placing the photovoltaic module obtained in Step S11 in an environmental test chamber for heating, so that the temperature of the photovoltaic module reaches the target temperature; Step S13, removing the photovoltaic module from the environmental test chamber, stopping the insulation of the infrared temperature probe test point, and placing the infrared temperature probe at the infrared temperature test point; continuing to insulate the thermocouple temperature test point, and placing the thermocouple at the thermocouple temperature test point; Step S14, when the temperature difference displayed by the infrared temperature probe and the thermocouple is less than a preset value, stopping the insulation of the thermocouple temperature test point; thereafter, as the temperature of the photovoltaic module decreases, testing the IV characteristic value of the photovoltaic module at a preset temperature interval.

[0007] As an optional approach, step S15 is also included: performing least squares fitting on the test data obtained in step S14 to obtain the relationship between the electrical performance parameters of the photovoltaic module and temperature.

[0008] As an optional solution, the infrared temperature probe has one test point, and the thermocouple temperature test point has three test points.

[0009] As an optional solution, the insulation of the temperature test point of the photovoltaic module in step S11 includes covering the temperature test point with insulation cotton.

[0010] As an optional solution, step S13 includes: step S131, selecting an infrared temperature probe and three thermocouples to perform temperature tests on their respective temperature test points; step S132, removing the insulation cotton from the temperature test point corresponding to the infrared temperature probe, and placing the three thermocouples under the insulation cotton at their respective temperature test points.

[0011] As an optional solution, when the temperature difference between the infrared temperature probe and the thermocouple is less than 2°C, the insulation cotton covering the three thermocouples is removed.

[0012] As an optional solution, in step S14, the flash test is stopped when the temperature of the photovoltaic module drops to 30°C.

[0013] As an optional option, the preset temperature interval is 5°C.

[0014] As an optional measure, the target temperature in step S12 is set to 80-90℃.

[0015] As an optional solution, in step S12, the photovoltaic module is kept heated for 50-60 minutes in an environment where the target temperature is set to 80-90℃.

[0016] Compared with the prior art, the embodiments of this disclosure have at least the following advantages:

[0017] In photovoltaic (PV) module temperature coefficient (TCC) testing, infrared temperature probes and thermocouples are used to detect the temperature at different test points. Based on the characteristics of these probes and thermocouples, after determining their locations, these test points are insulated. The PV module is then placed in an environmental test chamber and heated to a preset temperature. After removing the PV module from the chamber, the insulation of the infrared temperature probe test points is stopped, and the infrared temperature probe is placed at the infrared temperature probe test point. The insulation of the thermocouple test points continues, and the thermocouple is placed at the thermocouple temperature test point. Because of the insulation measures taken for the thermocouples, they can quickly display the actual temperature of the PV module even when the module temperature is high. This means that at higher temperatures, the temperature difference between the various test points measured by the infrared temperature probe and thermocouples meets the standard requirements. Therefore, IV characteristic numerical testing can begin when the PV module temperature is high, thus meeting the requirement of a 30°C test temperature range.

[0018] The testing method provided in this disclosure does not require all temperature probes to be infrared temperature probes, which can reduce testing costs. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or in the conventional technology, 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.

[0020] Figure 1 This is a flowchart illustrating a method for testing the temperature coefficient of a photovoltaic module in an embodiment of this application. Figure 1 ;

[0021] Figure 2 This is a schematic diagram showing the location of temperature test points as specified in the ICE 60891 standard specification in the existing technology;

[0022] Figure 3 This is a schematic diagram of the photovoltaic module covered with insulation cotton in an embodiment of this application;

[0023] Figure 4 This is a schematic diagram showing the arrangement of infrared temperature probes and thermocouples at corresponding temperature test points on the back of the photovoltaic module in an embodiment of this application;

[0024] Figure 5 This is a flowchart illustrating step S13 in an embodiment of this application;

[0025] Figure 6 These are the temperature values ​​at various temperature test points when the photovoltaic module is cooled to one of the temperatures described in this application embodiment;

[0026] Figure 7 This refers to the temperature difference values ​​between various temperature test points in the insulated area and the uninsulated area shown in the embodiments of this application. Attached image description:

[0028] 1. Photovoltaic modules; 2. Insulation cotton; 3. Adhesive tape; 4. Thermocouples; 5. Infrared temperature probes. Detailed Implementation

[0029] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0030] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when used in this specification, the words “comprising” and / or “including” indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the various 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. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0032] Before photovoltaic modules can be put into the market, they need to undergo a series of tests to prove their reliability. The reliability test items are divided into three categories: electronic characteristic test, environmental test and mechanical test. The embodiments of the present invention are mainly for a method for testing the temperature coefficient of photovoltaic modules.

[0033] As is well known, the industry currently generally adopts the test of the temperature coefficient of photovoltaic modules with reference to clause 4.4 of ICE 60891:2009 standard. The test requires that the test temperature span be ≥30℃ and the temperature uniformity of the four points be ±2℃. However, the existing test methods in the industry cannot meet the requirement of a test temperature span greater than or equal to 30℃ while meeting the condition that the temperature uniformity of each test point is ±2℃.

[0034] Therefore, based on this situation, the present disclosure provides a method for testing the temperature coefficient of photovoltaic modules to solve the above-mentioned problems.

[0035] Reference Figure 1 As shown below, a method for testing the temperature coefficient of a photovoltaic module according to an embodiment of this disclosure will be described in detail below, including the following steps:

[0036] Step S11: Determine the location of the temperature test point on the photovoltaic module 1 to be tested, and keep the location of the temperature test point on the photovoltaic module 1 warm. The temperature test point includes at least one infrared temperature probe test point and at least one thermocouple temperature test point.

[0037] Step S12: Place the photovoltaic module 1 obtained in step S11 in an environmental test chamber for heating until the temperature of the photovoltaic module reaches the target temperature;

[0038] Step S13: Remove the photovoltaic module 1 from the environmental test chamber, stop the heat preservation of the infrared temperature probe test point, and place the infrared temperature probe 5 at the infrared temperature test point; continue to preserve the temperature of the thermocouple temperature test point, and place the thermocouple 4 at the thermocouple temperature test point.

[0039] Step S14: When the temperature difference between the infrared temperature probe 5 and the thermocouple 4 is less than the preset value, stop keeping the thermocouple temperature test point warm; then, as the temperature of the photovoltaic module 1 decreases, test the IV characteristic value of the photovoltaic module 1 at the preset temperature interval.

[0040] Before placing the photovoltaic module 1 under test into the environmental test chamber, the location of the temperature test points on the photovoltaic module 1 is determined according to the requirements of the standard specifications and based on the characteristics of the infrared temperature probe 5 and thermocouple 4. The temperature test points of the photovoltaic module 1 are then insulated to ensure that the photovoltaic module 1 does not cool down too quickly after being heated in the environmental test chamber for a period of time, thus maintaining a relatively high initial temperature. After removing the photovoltaic module 1 from the environmental test chamber, the insulation of the infrared temperature probe test points is stopped, and the infrared temperature probe 5 is placed at the infrared temperature test point. The insulation of the thermocouple temperature test points continues, and the thermocouple 4 is placed at the thermocouple temperature test point. Due to the insulation measures taken for the thermocouple 4, the thermocouple 4 can quickly display the actual temperature of the photovoltaic module 1 when the temperature is high. That is, at a high temperature, the temperature difference between the various test points measured by the infrared temperature probe 5 and the thermocouple 4 can meet the standard requirements. Therefore, IV characteristic numerical testing can begin when the photovoltaic module 1 is at a high temperature, thus meeting the requirement that the test temperature range reach 30℃.

[0041] Each step is explained in detail below:

[0042] Please continue to refer to Figure 1 , Figure 2 As shown, in step S11, the location of the temperature test point on the photovoltaic module 1 to be tested is determined, and the location of the temperature test point on the photovoltaic module 1 is kept warm. The temperature test point includes at least one infrared temperature probe test point and at least one thermocouple temperature test point.

[0043] In this embodiment, it should be noted that the ICE 60891:2009 standard specifies that temperature coefficient testing is divided into heating method and cooling method. The commonly used method in the industry is the cooling method, which involves placing the photovoltaic module 1 in an environmental test chamber and heating it to a constant temperature for a period of time before moving the photovoltaic module 1 to a maximum power tester to test the electrical performance parameters (Isc / Voc / Pmp). The temperature of the temperature test points on the back of the photovoltaic module 1 is monitored. The temperature test points include at least one infrared temperature probe test point and at least one thermocouple temperature test point. In this embodiment, one infrared temperature probe test point and three thermocouple temperature test points are used as an example for illustration. The positions of the four test points are as follows: Figure 2 As shown, the relationship between the electrical performance parameters of photovoltaic module 1 and temperature—the temperature coefficient—is finally obtained.

[0044] Please continue to refer to Figure 3As shown, in this embodiment, according to the requirements of ICE 60891:2009 standard, insulation is first performed at the four temperature test points of the photovoltaic module 1 under test. Preferably, insulation cotton 2 is covered at the temperature test points for insulation. The insulation cotton 2 is fixed to the back of the photovoltaic module 1 by adhesive tape 3. The insulation cotton 2 can be EVA foam, which has good heat insulation function.

[0045] Please continue to refer to Figure 1 As shown, in step S12, the photovoltaic module 1 obtained in step S11 is placed in an environmental test chamber and heated to bring the temperature of the photovoltaic module to the target temperature.

[0046] In this embodiment, it should be noted that the photovoltaic module 1, after heat preservation treatment, is placed in an environmental test chamber. A heating device is then used to heat the environmental test chamber until the temperature reaches the target temperature, and this temperature is maintained for a period of time. Preferably, the target temperature is set to 80-90℃, and the photovoltaic module 1 is kept at 80-90℃ for 50-60 minutes to achieve thermal equilibrium.

[0047] In one example, the heating device in this embodiment can be an electric heater or a light heater. This embodiment does not limit which form is used.

[0048] Please continue to refer to Figure 1 , Figure 5 As shown, in step S13, the photovoltaic module 1 is removed from the environmental test chamber, the heat preservation of the infrared temperature probe test point is stopped, and the infrared temperature probe 5 is placed at the infrared temperature test point; the heat preservation of the thermocouple temperature test point is continued, and the thermocouple 4 is placed at the thermocouple temperature test point.

[0049] Including step S131, selecting an infrared temperature probe 5 and three thermocouples 4 to perform temperature tests on their respective temperature test points;

[0050] Reference Figure 3 , Figure 4 As shown in this embodiment, it should be noted that after the photovoltaic module 1, which has undergone heat treatment, is heated, it is removed and placed on a maximum power tester. At this time, an infrared temperature probe 5 and three thermocouples 4 are selected to test the temperature at their respective test points.

[0051] Step S132: Remove the insulation cotton 2 from the temperature test point corresponding to the infrared temperature probe 5, and place the three thermocouples 4 under the insulation cotton 2 at their respective temperature test points.

[0052] Reference Figure 3 , Figure 4As shown in this embodiment, it should be noted that during the test, the photovoltaic module 1 is removed from the environmental test chamber, and the insulation of the infrared temperature probe test point is stopped. That is, the insulation cotton 2 at the temperature test point corresponding to the infrared temperature probe 5 is removed, and the infrared temperature probe 5 is used to test the temperature of the temperature test point. At this time, the temperature measured by the infrared temperature probe 5 is the actual temperature of the photovoltaic module 1. The insulation of the thermocouple temperature test point continues, and then the three thermocouples 4 are placed under the insulation cotton 2 at their respective temperature test points to conduct temperature tests.

[0053] Step S14: When the temperature difference between the infrared temperature probe 5 and the thermocouple 4 is less than the preset value, stop keeping the thermocouple temperature test point warm; then, as the temperature of the photovoltaic module 1 decreases, test the IV characteristic value of the photovoltaic module 1 at the preset temperature interval.

[0054] Reference Figure 3 , Figure 4 As shown in this embodiment, it should be noted that after the infrared temperature probe 5 and the three thermocouples 4 measure the temperature at their respective test points, the temperature deviations between them are compared. If the measured temperature deviation is less than a preset value, the insulation of the thermocouple temperature test points is stopped, that is, the remaining three pieces of insulation cotton 2 are also removed, and the flash test begins. Subsequently, as the temperature of the photovoltaic module 1 decreases, the IV characteristic values ​​of the photovoltaic module 1 are tested at preset temperature intervals. Furthermore, during this process, if the temperature difference of the four temperature probes meets the requirements and the formal test begins, it is no longer required to apply the insulation cotton 2.

[0055] Preferably, the preset value is set to 2℃. When the temperature difference between the infrared temperature probe 5 and the thermocouple 4 is less than 2℃, the insulation cotton 2 covering the three thermocouples 4 is removed.

[0056] In this embodiment, it should also be noted that the temperature range for the photovoltaic module 1 during the flash test using the cooling method is set to 30-60℃, and the preset temperature interval is set to 5℃. Specifically, the photovoltaic module 1 is subjected to a flash test once at each of the following temperatures: 60℃, 55℃, 50℃, 45℃, 40℃, 35℃, and 30℃, thereby obtaining test data at seven different temperatures. The flash test is stopped when the temperature of the photovoltaic module 1 drops to 30℃.

[0057] Reference Figure 1 As shown, the photovoltaic module temperature coefficient test method also includes step S15, performing least squares fitting on the test data obtained in step S14 to obtain the relationship between the electrical performance parameters of photovoltaic module 1 and temperature.

[0058] In this embodiment, it should be noted that the test data of photovoltaic module 1 measured by the cooling method is fitted by the least squares method, which can yield the relationship between the electrical performance parameters of photovoltaic module 1 and temperature, i.e., the temperature coefficient.

[0059] The implementation principle of this embodiment is as follows: In this embodiment, the insulation cotton 2 is covered on the thermocouple 4 mainly because the photovoltaic module 1 will start to cool down after being taken out of the environmental test chamber. Since the thermocouple 4 conducts heat slowly, the temperature displayed when it first comes into contact with the photovoltaic module 1 is not the actual temperature of the photovoltaic module 1. The infrared temperature probe 5 can test the actual temperature of the photovoltaic module 1 in real time. Therefore, if the temperature difference between the infrared temperature probe 5 and the thermocouple 4 is within 2°C according to the standard specifications, the temperature of the photovoltaic module 1 is already relatively low, and it is impossible to collect the maximum power data of the photovoltaic module 1 when the temperature is high.

[0060] When insulation cotton 2 is covered on thermocouple 4, thermocouple 4 can be heated up quickly. In a short time, the temperature difference between infrared temperature probe 5 and thermocouple 4 can be reduced to within 2°C. That is, when the temperature of photovoltaic module 1 is still high, the temperature difference between infrared temperature probe 5 and thermocouple 4 can be reduced to within 2°C to meet the standard requirements. Thus, IV characteristic numerical testing can be started when the temperature of photovoltaic module 1 is high, thereby meeting the requirement that the test temperature range should reach 30°C.

[0061] like Figure 6 As shown, when the test temperature of photovoltaic module 1 drops to 52.1℃, temperature tests are conducted on four temperature test points using thermocouple 4 and infrared temperature probe 5. It is found that after the photovoltaic module 1 adopts the local heat preservation treatment of this embodiment and adjusts the heat preservation removal order of infrared temperature probe test points and thermocouple temperature test points, the temperature deviation of each test point can be within 2℃.

[0062] After the photovoltaic module 1 is removed from the environmental test chamber, the insulation of the infrared temperature probe test point is stopped, that is, the insulation cotton 2 at the temperature test point of the infrared temperature probe 5 is removed. The temperature measured by the infrared temperature probe 5 is the actual temperature of the photovoltaic module 1. The insulation of the thermocouple temperature test point continues, and the thermocouple 4 is placed at the thermocouple temperature test point. Therefore, the thermocouple 4 can test a temperature close to that of the infrared temperature probe 5 when covered with insulation cotton 2.

[0063] Please refer to Figure 3 , Figure 7 As shown, since this embodiment only provides localized insulation for the temperature test point, the temperature of the locally insulated area and the uninsulated area may differ during testing. Therefore, this embodiment also uses actual experiments to further verify the temperature difference between the locally insulated area and the uninsulated area. Figure 7The data in the table also shows that the temperature difference between the partially insulated area and the uninsulated area was small during the test, and the extreme temperature values ​​of the three temperature test points and their surroundings were all less than 2℃, which meets the standard requirements.

[0064] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of this application and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of this application should be included within the protection scope of this application. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A method for testing the temperature coefficient of a photovoltaic module, characterized in that, Includes the following steps: Step S11: Determine the location of the temperature test point on the photovoltaic module (1) to be tested, and cover the location of the temperature test point of the photovoltaic module (1) with insulation cotton (2) for insulation. The temperature test point includes at least one infrared temperature probe test point and at least three thermocouple temperature test points. Step S12: Place the photovoltaic module (1) obtained in step S11 in an environmental test chamber for heating, so that the temperature of the photovoltaic module (1) reaches the target temperature of 80-90℃, and the photovoltaic module (1) is kept heated for 50-60 minutes in the environment of the target temperature of 80-90℃. Step S13: Remove the photovoltaic module (1) from the environmental test chamber, select an infrared temperature probe (5) and three thermocouples (4) to test the temperature at their respective temperature test points; remove the insulation cotton (2) at the infrared temperature probe test point corresponding to the infrared temperature probe (5) to stop the insulation of the infrared temperature probe test point, and place the infrared temperature probe (5) at the infrared temperature probe test point; continue to insulate the thermocouple temperature test point, and place the three thermocouples (4) under the insulation cotton (2) at their respective thermocouple temperature test points; Step S14: When the temperature difference between the infrared temperature probe (5) and the thermocouple (4) is less than the preset value of 2°C, remove the insulation cotton (2) covering the three thermocouples (4) and stop the insulation of the thermocouple temperature test points; then, as the temperature of the photovoltaic module (1) decreases, test the IV characteristic value of the photovoltaic module (1) at the preset temperature interval.

2. The method for testing the temperature coefficient of photovoltaic modules according to claim 1, characterized in that, It also includes step S15, which involves performing least squares fitting on the test data obtained in step S14 to determine the relationship between the electrical performance parameters of the photovoltaic module (1) and the temperature.

3. The method for testing the temperature coefficient of photovoltaic modules according to claim 1, characterized in that, In step S14, the flash test is stopped when the temperature of the photovoltaic module (1) drops to 30°C.

4. The method for testing the temperature coefficient of photovoltaic modules according to claim 3, characterized in that, The preset temperature interval is 5°C.

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