Test method and test system for rapidly detecting PID reliability of solar cell

Abstract

The invention provides a test method and a test system for rapidly detecting PID reliability of a solar cell, the test system comprises a constant temperature environment box body, a sealed container and a power supply, the sealed container and the power supply are respectively arranged inside and outside the constant temperature environment box body, a cell bearing platform is arranged in the sealed container, the solar cell to be tested is externally connected with the power supply, and a fan is also arranged in the sealed container. An acetic acid solution is injected into the bottom of the sealed container, and the front and back surfaces of the solar cell to be detected are infiltrated with a NaCl solution. Certain temperature is simulated through the constant-temperature environment box body, certain humidity is simulated through cooperation of the sealed container, the acetic acid solution, the NaCl solution and the fan, bias voltage is simulated through an external reverse direct-current power supply, the solar cell piece is made to be in a certain negative voltage condition, and finally the output power of the solar cell piece is tested. And calculating the attenuation degree of the output power of the solar cell before and after the PID test so as to judge whether the solar cell has the anti-PID effect capability or not.

Description

Technical Field

[0001] The invention relates to the technical field of solar cell production, and specifically, it shows a test method and a test system for quickly detecting the reliability of PID of solar cell sheets. Background Art

[0002] A solar cell is a photoelectric semiconductor wafer that uses sunlight to generate electricity directly. As long as a certain light intensity is met, it can output voltage and generate current in the presence of a circuit. Simply put, a solar cell is a device that directly converts light energy into electrical energy through the photoelectric effect.

[0003] Solar cells have excellent photoelectric properties. They are also a renewable and environmentally friendly way to generate electricity. They do not produce greenhouse gases such as carbon dioxide during the power generation process and do not pollute the environment. Therefore, solar cells are currently widely used around the world.

[0004] PID (Potential Induced Degradation) refers to the phenomenon that the power of solar cells decays when they are subjected to a certain external voltage for a long time.

[0005] During the operation of outdoor power stations, lightning protection measures must be considered, so the frame of the module is grounded, which will cause a negative bias to form between the module and the frame. During the negative bias process, the frame is positively charged, so the Na + Migration will be carried out. + Under the action of the electric field, it passes through the glass and film, gathers in the film layer on the surface of the battery cell, and then diffuses into the defects (dislocations) of the silicon crystal, passes through the PN junction, and forms a leakage current channel at both ends of the PN junction.

[0006] PID is one of the important factors that cause the electrical performance of solar modules to degrade during long-term operation. Solar cells need to undergo PID testing before they can be used. Traditional battery-side PID reliability testing equipment, such as the Freiberg Instrument PIDcon tester, often requires the use of a stacking structure of glass, EVA film (Ethylene-vinyl Acetate Copolymer, EVA, ethylene-vinyl acetate copolymer) and cells. The high temperature during the preparation process will cause the EVA to melt, and the glass and cells will be bonded together and cannot be easily separated without loss. This results in only a single test after the PID test, which is not conducive to the characterization and analysis of solar cells. In addition, the solar cell modules used for testing are scrapped after the test, resulting in increased costs.

[0007] Therefore, finding a test method that can quickly detect the reliability of solar cell PID is an urgent problem to be solved. Summary of the invention

[0008] One of the purposes of the present invention is to address the deficiencies of the prior art and to provide a test method for quickly detecting the PID reliability of solar cells which is simple, time-saving and low-cost.

[0009] The second purpose of the present invention is to provide a test system for quickly detecting the PID reliability of solar cells in view of the deficiencies of the prior art.

[0010] Based on this, the present invention discloses a test method for quickly detecting the reliability of solar cell PID, comprising the following steps:

[0011] Step 1: Sample preparation:

[0012] Take a solar cell to be tested, weld the welding strips on the front and back of the solar cell to be tested, respectively, and connect the welded welding strips on the front and back of the solar cell to be tested to a bus bar respectively. The preparation of the solar cell to be tested is completed, and the initial power of the sample is tested by IV tester, which is recorded as P0;

[0013] Step 2: Prepare the solution:

[0014] Prepare solution a, i.e. acetic acid solution; prepare solution b, i.e. NaCl solution;

[0015] Step 3: Test environment preparation:

[0016] A constant temperature environment box is prepared, a sealed container is placed in the constant temperature environment box, a battery cell support platform is arranged in the middle of the sealed container, a fan is arranged on one side of the sealed container, and a power supply is arranged outside the constant temperature environment box;

[0017] Step 4: Testing:

[0018] First, pour solution a into a sealed container; then completely soak the front and back of the solar cell to be tested in solution b, and place it on the cell support platform, so that the front and back of the solar cell to be tested are exposed to the outside, and the two bus bars on the solar cell to be tested are respectively connected to the positive and negative poles of the external power supply; then, set the temperature of the constant temperature environment box to 85±5℃, turn on the fan, and start the power supply;

[0019] The test time is 8 hours. When the test time is up, turn off the power supply and the fan, and let it stand for 15 to 30 minutes. Then take out the solar cell to be tested and use the IV tester to test the attenuation power of the sample, which is recorded as P 衰 ;

[0020] The calculation formula of attenuation data η is:

[0021]

[0022] The testing work is completed.

[0023] Preferably, in step 1: a plurality of array-arranged welding strips are welded to the front and back sides of the solar cell to be tested, one side of the welding strips is aligned, and the welding strips on the same side are welded together to a bus bar, one end of which extends outward.

[0024] Preferably, in step 2: 10 L of acetic acid solution is prepared with a concentration of 0.3% to 0.5%, and the concentration of NaCl solution is a saturated solution at room temperature and pressure.

[0025] Preferably, in step three: the wind direction of the fan is to blow air from top to bottom in a vertical direction.

[0026] Preferably, in step 4: a certain distance is left between the bottom end of the battery cell supporting platform and the liquid surface of the solution a in the sealed container.

[0027] Further preferably, there are two battery cell supporting platforms vertically arranged in the sealed container in a parallel and spaced manner, and a placing platform portion is provided in the middle of the inner wall of the battery cell supporting platform protruding inwardly horizontally.

[0028] Further preferably, the battery cell support platform is made of corrosion-resistant material and is integrally formed.

[0029] The present invention also discloses a test system for rapidly detecting the PID reliability of solar cell sheets. The test system comprises: a constant temperature environment box, a sealed container, and a power supply. The sealed container is arranged inside the constant temperature environment box, and the power supply is arranged outside the constant temperature environment box. A cell support platform for placing the solar cell sheet to be tested is arranged in the middle position of the sealed container, and the solar cell sheet to be tested is connected to an external power supply. A fan is arranged at a side position of the sealed container, an acetic acid solution is injected into the bottom of the sealed container, and the front and back sides of the solar cell sheet to be tested are soaked with a NaCl solution.

[0030] Compared with the prior art, the invention has the following beneficial effects: the constant temperature environment box is used to simulate the test conditions at a certain temperature, and the sealed container, acetic acid solution, NaCl solution and fan are used to simulate the test conditions at a certain humidity, that is, the NaCl solution is used to simulate the NaCl in PID. +Corrosion, acetic acid solution is used to simulate the acid produced by the hydrolysis of the film on the solar cell, and the fan can improve the air circulation in the sealed container to avoid excessive airflow concentration in a local space in the sealed container. The bias voltage is simulated by an external reverse DC power supply to put the solar cell in a certain negative voltage condition. Finally, the output power of the solar cell is tested, and the attenuation degree of the output power of the solar cell before and after the PID test is calculated to determine whether the solar cell has the ability to resist the PID effect. If the attenuation ratio of the output power of the solar cell before and after the PID effect test is less than 25%, it is considered that the relevant process for manufacturing the solar cell has met the anti-PID ability standard, and vice versa.

[0031] The test system proposed in the present invention can save a lot of time, has a small size, is easy to transport, and greatly reduces the cost of PID detection; the test method proposed in the present invention does not require high-temperature lamination, and the test system is easy to disassemble after the test, which is beneficial to the subsequent characterization and analysis of the solar cell used in the test, and improves the timeliness and accuracy of the judgment of the solar cell PID performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of a test system for quickly detecting the PID reliability of a solar cell sheet according to the present invention;

[0033] Figure 2 is a schematic diagram of how to prepare a sample according to an embodiment of the present invention;

[0034] Relevant marks in the attached drawings: 1-constant temperature environment box, 2-sealed container, 3-power supply, 4-cell support platform, 41-shelf part, 5-fan, 6-solar cell to be tested, 61-soldering strip, 62-bus bar. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0036] See also Figure 1 and Figure 2As shown. A test system for rapidly detecting the PID reliability of a solar cell in this embodiment comprises a constant temperature environment box 1, a sealed container 2, and a power supply 3. The sealed container 2 is arranged in the constant temperature environment box 1. The sealed container is not a completely closed container. Here, it means that it has good sealing performance. The sealed container can be opened. The constant temperature environment box is a conventional constant temperature box, and the temperature can be set. The power supply 3 is arranged outside the constant temperature environment box 1 and is a DC power supply. A cell support platform 4 for placing a solar cell 6 to be tested is arranged in the middle position of the sealed container 2. The solar cell 6 to be tested is externally connected to the power supply 3. A fan 5 is arranged at the side position of the sealed container 2. Acetic acid solution a is injected into the bottom of the sealed container 2, and the front and back sides of the solar cell 6 to be tested are soaked with NaCl solution b.

[0037] The test conditions of PID in the prior art are: 85℃ relative temperature, 85% relative humidity, negative loading voltage. The existing test method is: first cut the solar cell in half, then weld it into strings, lay the string of cells flat on the back film (below is the back glass / backboard), cover the front film and front glass in turn, and then perform high-temperature lamination; the laminated components are formed, and then use silicone to seal the frame and junction box. After sealing, let it stand for a period of time before performing PID testing.

[0038] First, test component IV to obtain the initial power P0 while retaining the EL image; then connect the component to a 1500V power supply, connect the component frame to the positive pole of the power supply, and connect the positive pole of the component to the negative pole of the power supply. Place the component in an environment with a temperature of 85°C and a humidity of 85%. The test time is 96h / time, and there are two tests in total. Each time, test components IV and EL to obtain P96 and P192 respectively.

[0039]

[0040] The above data of PID96 and PID192 are obtained, the test is completed, and the component is scrapped.

[0041] In this embodiment, the constant temperature environment box is used to simulate the test conditions at a certain temperature, and the NaCl solution is used to simulate the Na in the PID. + The solar cell is corroded by using acetic acid solution to simulate the acid produced by the hydrolysis of the film on the solar cell. The fan can improve the air circulation in the sealed container to avoid excessive air flow concentration in a certain local space in the sealed container. The bias voltage is simulated by an external reverse DC power supply to put the solar cell under a certain negative voltage condition.

[0042] Among them, a number of array-arranged welding strips 61 are welded on the front and back sides of the solar cell 6 to be tested, one side of the several welding strips 61 is aligned, and the several welding strips 61 on the same side are welded together on a bus bar 62, one end of the bus bar 62 extends outward, and the bus bar is used to concentrate and transmit the electric energy generated by the solar cell, which is convenient for external power supply.

[0043] The acetic acid solution a is prepared in 10 L with a concentration of 0.3% to 0.5%, and the NaCl solution b is prepared as a saturated solution at room temperature and pressure.

[0044] The wind direction of the fan 5 is to blow air from top to bottom in the vertical direction to form an internal circulation inside the sealed container 2.

[0045] The method for making the front and back sides of the solar cell sheet 6 to be tested soaked with the NaCl solution b is to completely soak the front and back sides of the solar cell sheet 6 to be tested in the NaCl solution b.

[0046] There is a certain distance between the bottom of the cell support platform 4 and the liquid surface of the solution a in the sealed container 2 to prevent the bottom of the cell support platform from being corroded by being immersed in the acetic acid solution for a long time.

[0047] Among them, there are two battery cell supporting platforms 4 vertically arranged in the sealed container 2 in the form of parallel intervals. The battery cell supporting platforms 4 can be hung on the side wall of the sealed container 2. In short, it is sufficient to ensure that the bottom of the battery cell supporting platform does not contact the liquid surface of the acetic acid solution, and a placing platform 41 is horizontally protruded inwardly in the middle of the inner wall of the battery cell supporting platform 4. The two ends of the solar cell 6 to be tested are respectively placed on the placing platform 41 of the two battery cell supporting platforms 4, which can make the front and back sides of the solar cell 6 to be tested fully exposed to the environment of the sealed container 2.

[0048] The cell support platform 4 is made of corrosion-resistant material, such as PTFE, PVDF, etc., and is integrally formed.

[0049] The PID reliability test of the solar cell based on the above test system specifically includes the following steps:

[0050] Step 1: Sample preparation:

[0051] Take a solar cell to be tested, weld the welding strips on the front and back of the solar cell to be tested, respectively, and connect the welded welding strips on the front and back of the solar cell to be tested to a bus bar respectively. The preparation of the solar cell to be tested is completed, and the initial power of the sample is tested by IV tester, which is recorded as P0;

[0052] Step 2: Prepare the solution:

[0053] Prepare solution a, i.e. acetic acid solution; prepare solution b, i.e. NaCl solution;

[0054] Step 3: Test environment preparation:

[0055] A constant temperature environment box is prepared, a sealed container is placed in the constant temperature environment box, a battery cell support platform is arranged in the middle of the sealed container, a fan is arranged on one side of the sealed container, and a power supply is arranged outside the constant temperature environment box;

[0056] Step 4: Testing:

[0057] First, pour solution a into a sealed container; then completely soak the front and back of the solar cell to be tested in solution b, and place it on the cell support platform, so that the front and back of the solar cell to be tested are exposed to the outside, and the two bus bars on the solar cell to be tested are respectively connected to the positive and negative poles of the external power supply; then, set the temperature of the constant temperature environment box to 85±5℃, turn on the fan, and start the power supply;

[0058] The test time is 8 hours. When the test time is up, turn off the fan and power, and let it stand for 15 to 30 minutes. Then take out the solar cell to be tested and use the IV tester to test the attenuation power of the sample, which is recorded as P 衰 ;

[0059] The calculation formula of attenuation data η is:

[0060]

[0061] The testing work is completed.

[0062] If the attenuation ratio of the output power of the solar cell before and after the PID effect test is less than 25%, it is considered that the anti-PID capability of the relevant process for manufacturing the solar cell has met the standard, and vice versa.

[0063] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A test method for quickly detecting the reliability of solar cell PID, characterized in that: The steps include: Step 1: Sample preparation: Take a solar cell sheet (6) to be tested, weld a welding strip (61) on the front and back sides of the solar cell sheet (6), respectively, connect the welding strips (61) welded on the front and back sides of the solar cell sheet (6) to be tested to a bus bar (62), respectively, and the preparation of the solar cell sheet (6) to be tested is completed. Use an IV tester to test the initial power of the sample, which is recorded as P0; Step 2: Prepare the solution: Prepare solution a, i.e. acetic acid solution; prepare solution b, i.e. NaCl solution; Step 3: Test environment preparation: A constant temperature environment box (1) is prepared, a sealed container (2) is placed in the constant temperature environment box (1), a battery cell support platform (4) is arranged in the middle of the sealed container (2), a fan (5) is arranged on one side of the interior of the sealed container (2), and a power source (3) is arranged outside the constant temperature environment box (1); Step 4: Testing: First, pour solution a into a sealed container (2); then completely immerse the front and back sides of the solar cell (6) to be tested in solution b and place it on a cell support platform (4), so that the front and back sides of the solar cell (6) to be tested are exposed to the outside, and two bus bars (62) on the solar cell (6) to be tested are respectively connected to the positive and negative electrodes of an external power source (3); then, set the temperature of the constant temperature environment box (1) to 85±5°C, turn on the fan (5), and start the power source (3); The test time is 8 hours. When the test time is up, turn off the power supply (3), turn off the fan (5), and let it stand for 15 to 30 minutes. Then take out the solar cell to be tested (6) and use an IV tester to test the attenuation power of the sample, which is recorded as P 衰 ; The calculation formula of attenuation data η is: The testing work is completed.

2. A method for rapidly detecting the reliability of solar cell PID according to claim 1, characterized in that: In the step 1, a plurality of array-arranged welding strips (61) are respectively welded on the front and back sides of the solar cell sheet (6) to be tested, one side edge of the plurality of welding strips (61) is aligned, and the plurality of welding strips (61) on the same side are welded together on a bus bar (62), one end of the bus bar (62) extending outward.

3. A method for rapidly detecting the reliability of solar cell PID according to claim 1, characterized in that: In the step 2, 10 L of acetic acid solution is prepared with a concentration of 0.3% to 0.5%, and the NaCl solution is prepared as a saturated solution at room temperature and pressure.

4. A method for rapidly detecting the reliability of solar cell PID according to claim 1, characterized in that: In step three: the wind direction of the fan (5) is to blow air from top to bottom in the vertical direction.

5. A method for rapidly detecting the reliability of solar cell PID according to claim 1, characterized in that: In the step 4: a certain distance is left between the bottom end of the cell support platform (4) and the liquid surface of the solution a in the sealed container (2).

6. A method for rapidly detecting the reliability of solar cell PID according to claim 5, characterized in that: A total of two battery cell support platforms (4) are vertically arranged in a parallel and spaced manner in the sealed container (2), and a placing platform portion (41) is provided in the middle of the inner wall of the battery cell support platform (4) protruding inwardly horizontally.

7. A method for rapidly detecting the reliability of solar cell PID according to claim 6, characterized in that: The battery cell support platform (4) is made of corrosion-resistant material and is integrally formed.

8. A test system for rapidly detecting the reliability of solar cell PID according to any test method of claims 1 to 7, characterized in that: The test system comprises: a constant temperature environment box (1), a sealed container (2), and a power source (3); the sealed container (2) is arranged in the constant temperature environment box (1); the power source (3) is arranged outside the constant temperature environment box (1); a cell support platform (4) for placing a solar cell (6) to be tested is arranged in the middle position of the sealed container (2); the solar cell (6) to be tested is connected to an external power source; a fan (5) is arranged at a side position of the sealed container (2); an acetic acid solution is injected into the bottom of the sealed container (2); and a NaCl solution is soaked on the front and back sides of the solar cell (6) to be tested.

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