Method for evaluating mechanical performance of photovoltaic module

Abstract

The invention provides a method for evaluating the mechanical performance of a photovoltaic module, and belongs to the technical field of photovoltaic cell testing, and the method comprises the steps: measuring the initial thickness of the position where each frame installation hole is located, and sequentially recording the initial thickness as H1, H2,... Hn; carrying out a mechanical performance load test on the photovoltaic module; measuring the thickness of the deformed position of each frame mounting hole after the test, and recording the thickness as h1, h2,..., hn in sequence; after the test, if the thickness of each frame mounting hole meets the condition that h is less than or equal to 1.5 H, the mechanical property of the frame mounting hole is evaluated to meet 1.5 times of the test load; if the thickness of each frame mounting hole satisfies 1.5 H < h < = 2H, evaluating that the mechanical property of the frame mounting hole satisfies one time of the test load; and if the thickness of each frame mounting hole meets the condition that h is greater than 2H, the mechanical performance of the frame mounting hole is evaluated to have failure risk. The reliability and the service life of the frame mounting hole under the working condition of ultimate load are evaluated by carrying out mechanical performance test on the position of the frame mounting hole.

Description

Technical Field

[0001] The invention belongs to the technical field of photovoltaic cell testing, and in particular relates to a method for evaluating the mechanical properties of a photovoltaic module. Background Art

[0002] The photovoltaic industry has developed rapidly, and photovoltaic power generation has been widely used. Various quality problems have occurred during use, causing serious economic losses. The load capacity of photovoltaic modules has become one of the key factors affecting the quality of modules. The purpose of mechanical performance verification is to determine the ability of modules to withstand external stress. It is used to verify the ability of modules to withstand wind, snow or ice loads at different installation angles, which is crucial to the reliability, power attenuation and service life of modules outdoors.

[0003] At present, in order to improve the utilization efficiency of solar energy, increase power generation, and reduce the operating cost of solar power generation, a photovoltaic power generation method that controls the rotation of the panel has been proposed, namely, a single-axis and dual-axis tracking system; the single-axis means that the panel assembly has only one degree of rotational freedom, tracking the sun in azimuth (east-west direction), and the dual-axis tracking system means tracking the movement of the sun in both azimuth and altitude. Due to the different installation methods of the single-axis and dual-axis tracking systems, the components deform greatly after being loaded. The mechanical performance limit test of conventional load testing equipment mainly tests the damage of the laminated parts of the components, and cannot effectively predict the mechanical performance limit of the frame mounting holes of photovoltaic components. Summary of the invention

[0004] The embodiment of the present invention provides a photovoltaic module mechanical performance evaluation method, which aims to evaluate the mechanical performance limit of the frame mounting hole after the photovoltaic module is installed, so as to ensure the reliability of the photovoltaic module frame after installation.

[0005] To achieve the above object, the technical solution adopted by the present invention is: to provide a method for evaluating the mechanical properties of a photovoltaic module, the method comprising the following steps: Initial data acquisition: According to the installation position of the photovoltaic module, determine the position of the frame installation hole and record it in sequence as K1, K2, ... Kn, where n is a positive integer; Measure the initial thickness of each frame mounting hole and record them as H1, H2, ... Hn; Mechanical properties test: Each frame mounting hole is bolted to fix the photovoltaic module; the photovoltaic module is subjected to mechanical performance load test; Measure the thickness of each frame mounting hole after deformation at the location after the test, and record them as h1, h2, .... hn in sequence; Mechanical performance evaluation: After the test, if the thickness of each frame mounting hole satisfies h≤1.5H, it is assessed that the mechanical properties of the frame mounting hole meet 1.5 times the test load; After the test, if the thickness of each frame mounting hole satisfies 1.5H<h≤2H, it is assessed that the mechanical properties of the frame mounting hole meet 1 times the test load; After the test, if the thickness of each frame mounting hole satisfies h>2H, it is assessed that the mechanical properties of the frame mounting hole have a risk of failure.

[0006] In one achievable manner, the method further includes evaluating the hardness of the frame mounting hole position after the load test: Measure the hardness of the profile at the location of each frame mounting hole, and record the initial hardness values ​​as Y1, Y2, ..., Yn in sequence; After the static mechanical load test, the hardness of the deformed profile at the location of each frame mounting hole is measured, and the hardness is recorded as y1, y2, ...yn in sequence; After the test, if the hardness of each frame mounting hole position satisfies y≤1.1Y, it is assessed that the mechanical properties meet 1.5 times the test load; After the test, if the hardness of each frame mounting hole position satisfies 1.1Y<y≤1.2Y, it is evaluated that the mechanical properties can meet 1 times the test load; After the test, if the hardness of each frame mounting hole position satisfies y>1.2Y, it is assessed that the mechanical performance has a risk of failure.

[0007] In one achievable manner, when measuring the initial thickness at the location of each frame mounting hole, three points are selected for each frame mounting hole for measurement and an average value is obtained, and the average value of the initial thickness of each frame mounting hole is recorded as H1, H2, ..., Hn in sequence; The position where the deformation of each frame mounting hole is the most serious is selected as the thickness measurement point, and the measurement is repeated three times to obtain the average thickness after deformation, which is recorded as h1, h2, ....hn in sequence.

[0008] In one achievable method, when measuring the initial hardness value, the initial hardness measurement is performed at a position within 5 cm around each frame mounting hole, and the average value is taken at three different points. The initial hardness values ​​are recorded as Y1, Y2, ..., Yn in sequence; After the load test, the hardness of each frame mounting hole after deformation is measured. The hardness of the position within 5 cm around each frame mounting hole is also measured. The average value is selected from three different points, and the hardness after deformation is recorded as y1, y2, ...yn in sequence.

[0009] In one achievable manner, the mechanical properties testing process is as follows: The photovoltaic modules are subjected to mechanical performance tests at 1.5 times the design load, including mechanical performance tests on the front and back of the modules.

[0010] In one achievable manner, the mechanical property test includes a static mechanical load test, and the photovoltaic module is subjected to a static mechanical load test of 5400 MPa on the front and 2400 MPa on the back. The front and back load tests last for 1 hour each and are repeated 3 times.

[0011] In one achievable manner, the mechanical property test further includes a dynamic mechanical load test, in which the front and back sides of the photovoltaic module are subjected to a dynamic mechanical load test of 1000 MPa and 1000 cycles, respectively, with a cycle frequency of 3-7 times / minute.

[0012] In one achievable manner, the mechanical property test further includes a voltage failure test: During the load test, the current continuity inside the photovoltaic module was monitored, 0.5A current was passed, and the voltage change was observed; When the voltage fluctuation is greater than ±0.5V or the voltage is short-circuited, it is evaluated as a failure.

[0013] In one achievable manner, the method further includes: evaluating whether a mounting hole of a component frame is torn or near torn.

[0014] The photovoltaic module mechanical performance evaluation method provided by the present invention has the following beneficial effects compared with the prior art: the purpose of the present invention is to evaluate the reliability and service life of the frame mounting holes under extreme load conditions by performing mechanical performance tests on the frame mounting hole positions, thereby providing a test basis for the working reliability of photovoltaic modules under different installation methods. DETAILED DESCRIPTION

[0015] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0016] The photovoltaic module mechanical performance evaluation method provided by the present invention is now described. The photovoltaic module mechanical performance evaluation method of the present invention includes initial data acquisition, mechanical performance testing, and mechanical performance evaluation.

[0017] Initial data acquisition, sample preparation: Step 1: According to the requirements of the photovoltaic module installation position, determine the positions of the frame mounting holes and record them in sequence as K1, K2, ... Kn, where n is a positive integer and is the total number of frame mounting holes on each photovoltaic module.

[0018] Step 2: Use a measuring tool to measure the initial thickness of the profile of each frame mounting hole. Select the left and right edges and the middle position of each frame mounting hole for initial thickness measurement. The average value is the initial thickness of the frame mounting hole, which is recorded as H1, H2...Hn in sequence.

[0019] Step three: Use a measuring tool to measure the hardness of the profile within 5 cm around each frame mounting hole. Take three different points on each frame mounting hole, measure three times and take the average value as the initial hardness of the frame mounting hole, recorded as Y1, Y2, ..., Yn.

[0020] Mechanical performance test: Step 4: Install the photovoltaic modules using bolts and gaskets.

[0021] The photovoltaic modules are subjected to mechanical performance tests at 1.5 times the design load, including mechanical performance tests on the front and back of the modules. During the test, the current continuity inside the module is monitored, 0.5A current is passed, and the voltage change is observed.

[0022] Step 5: Conduct static mechanical load tests on the photovoltaic module at 5400 MPa on the front and 2400 MPa on the back, each lasting 1 hour and repeated 3 times.

[0023] Step six, subjecting the photovoltaic module to a dynamic mechanical load test of 1000 MPa, 1000 cycles, and a cycle frequency of 3-7 times / minute.

[0024] After the mechanical properties are completed, the components are removed from the test equipment.

[0025] Step seven, record the appearance of the photovoltaic module, including the appearance of the module laminate, the appearance of the module frame, and the changes in the module frame mounting holes.

[0026] Step 8: Test the mechanical properties of the components. Measure the deformation of all frame mounting holes and select the location with the most severe deformation around the frame mounting holes. Use a measuring tool to measure and repeat the test three times at the location with the maximum deformation. The average value is the test value and is recorded as h1, h2, ....hn.

[0027] Step nine, use a measuring tool to measure the hardness of the profile within 5 cm around each frame mounting hole. Measure each frame mounting hole three times and take the average value, which is the hardness of the frame mounting hole after deformation and is recorded as y1, y2, ....yn.

[0028] Mechanical performance evaluation: Step 10: Monitor the current continuity inside the photovoltaic module. If the voltage fluctuation is greater than ±0.5V or the voltage is short-circuited, it is considered a failure.

[0029] Step 11, appearance evaluation: The photovoltaic module failure is caused by damage to the laminate and detachment from the frame.

[0030] A tear or near tear at the frame mounting hole is considered a failure.

[0031] Step 12, load test evaluation: After the test, if the thickness of each frame mounting hole satisfies h≤1.5H, it is assessed that the mechanical properties of the frame mounting hole meet 1.5 times the test load; After the test, if the thickness of each frame mounting hole satisfies 1.5H<h≤2H, it is assessed that the mechanical properties of the frame mounting hole meet 1 times the test load; After the test, if the thickness of each frame mounting hole satisfies h>2H, it is assessed that the mechanical properties of the frame mounting hole have a risk of failure. The load test data table is shown in Table 1.

[0032] Table 1 Load test data table

[0033] Step 13, hardness assessment: After the test, if the hardness of each frame mounting hole position satisfies y≤1.1Y, it is assessed that the mechanical properties meet 1.5 times the test load; After the test, if the hardness of each frame mounting hole position satisfies 1.1Y<y≤1.2Y, it is evaluated that the mechanical properties can meet 1 times the test load; After the test, if the hardness of each frame mounting hole position satisfies y>1.2Y, it is assessed that the mechanical performance has a risk of failure. The hardness test data table is shown in Table 2.

[0034] Table 2 Hardness test data table

[0035] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for evaluating the mechanical properties of a photovoltaic module, characterized in that: The method comprises the following steps: Initial data acquisition: According to the installation position of the photovoltaic module, determine the position of the frame installation hole and record it in sequence as K1, K2, ... Kn, where n is a positive integer; Measure the initial thickness of each frame mounting hole and record them as H1, H2, ... Hn; Mechanical properties test: Each frame mounting hole is bolted to fix the photovoltaic module; the photovoltaic module is subjected to mechanical performance load test; Measure the thickness of each frame mounting hole after deformation at the location after the test, and record them as h1, h2, .... hn in sequence; Mechanical performance evaluation: After the test, if the thickness of each frame mounting hole satisfies h≤1.5H, it is assessed that the mechanical properties of the frame mounting hole meet 1.5 times the test load; After the test, if the thickness of each frame mounting hole satisfies 1.5H<h≤2H, it is assessed that the mechanical properties of the frame mounting hole meet 1 times the test load; After the test, if the thickness of each frame mounting hole satisfies h>2H, it is assessed that the mechanical properties of the frame mounting hole have a risk of failure.

2. The photovoltaic module mechanical performance evaluation method according to claim 1, characterized in that: The method also includes a hardness assessment of the frame mounting hole location after the load test: Measure the hardness of the profile at the location of each frame mounting hole, and record the initial hardness values ​​as Y1, Y2, ..., Yn in sequence; After the static mechanical load test, the hardness of the deformed profile at the location of each frame mounting hole is measured, and the hardness is recorded as y1, y2, ...yn in sequence; After the test, if the hardness of each frame mounting hole position satisfies y≤1.1Y, it is assessed that the mechanical properties meet 1.5 times the test load; After the test, if the hardness of each frame mounting hole position satisfies 1.1Y<y≤1.2Y, it is evaluated that the mechanical properties can meet 1 times the test load; After the test, if the hardness of each frame mounting hole position satisfies y>1.2Y, it is assessed that the mechanical performance has a risk of failure.

3. The photovoltaic module mechanical performance evaluation method according to claim 2, characterized in that: When measuring the initial thickness at the location of each frame mounting hole, three points are selected for each frame mounting hole to measure and obtain the average value, and the average value of the initial thickness of each frame mounting hole is recorded as H1, H2, ..., Hn in sequence; The position where the deformation of each frame mounting hole is the most serious is selected as the thickness measurement point, and the measurement is repeated three times to obtain the average thickness after deformation, which is recorded as h1, h2, ....hn in sequence.

4. The photovoltaic module mechanical performance evaluation method according to claim 2, characterized in that: When measuring the initial hardness value, perform initial hardness measurement on the position within 5 cm around each frame mounting hole, select three different points to take the average value, and record the initial hardness values ​​as Y1, Y2, ... Yn in sequence; After the load test, the hardness of each frame mounting hole after deformation is measured. The hardness of the position within 5 cm around each frame mounting hole is also measured. The average value is selected from three different points, and the hardness after deformation is recorded as y1, y2, ...yn in sequence.

5. The photovoltaic module mechanical performance evaluation method according to claim 2, characterized in that: The mechanical properties test process is as follows: The photovoltaic modules are subjected to mechanical performance tests at 1.5 times the design load, including mechanical performance tests on the front and back of the modules.

6. The photovoltaic module mechanical performance evaluation method according to claim 5, characterized in that: The mechanical property test includes a static mechanical load test, in which the photovoltaic module is subjected to a static mechanical load test of 5400 MPa on the front and 2400 MPa on the back. The front and back load tests last for 1 hour each and are repeated 3 times.

7. The photovoltaic module mechanical performance evaluation method according to claim 6, characterized in that: The mechanical property test also includes a dynamic mechanical load test, in which the front and back sides of the photovoltaic module are subjected to a dynamic mechanical load test of 1000 MPa and 1000 cycles, respectively, with a cycle frequency of 3-7 times / minute.

8. The photovoltaic module mechanical performance evaluation method according to claim 1, characterized in that: The mechanical performance test also includes voltage failure test: During the load test, a 0.5A current was passed to monitor the current continuity inside the photovoltaic module and observe the voltage changes; When the voltage fluctuation is greater than ±0.5V or the voltage is short-circuited, it is evaluated as a failure.

9. The photovoltaic module mechanical performance evaluation method according to claim 1, characterized in that: The method further includes: component frame mounting hole tear or near tear assessment.

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